immortality

Transcription

immortality

Journal of Youths in Science
VOLUME 5
ISSUE 2
carbon nanotubes
the gateway to nanotechnology
rebuilding the bruised brain
AUGMENTED REALITY
the harbinger of sixth sense
the quest for
immortality
art by haiwa wu
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contents
SPRING 2013
Volume 5 Issue 2
CHEMISTRY
4 Carbon Nanotubes |AUSTIN SU
6 The Workings of Methylmercury| MARIA GINZBURG
8 Plastics: A Blessing and a Curse | NILAY SHAH
10 High-Temperature Superconductors| LILIA TANG
4
BIOLOGY
The Quest for Immortality|VARUN BHAVE 11
Neuroplasticity: I Can See With My Tongue | HARSHITA NADIMPALLI13
Rebuilding the Bruised Brain| MAXINDER S. KANWAL 14
Advances in Personalized Medicine | COLLIN DILLINGHAM 16
Controlled Release Using an Oral MATTIE MOUTON-JOHNSTON, 18
Drug Delivery System DIANE C. FORBES
16
Imagining Numbers and Space: Synesthesia|LILIA TANG 21
PHYSICS
23 The Mathematics of Drafting|FABIAN BOEMER
24 High Speed Rail|ERIC CHEN
24
31
MATHEMATICS & COMPUTER SCIENCE
Applications of Fourier Series & Transforms| PETER MANOHAR 26
Surgical Applications of a MATLAB-based VEDANT SINGH 28
Electroencephalography Program RUJUTA PATIL
Augmented Reality| ANJANA SRINIVAS 31
SPRING 2013 | JOURNYS | 3
CARBON NANOTUBES:
The
by Austin Su
Gateway
to
edited by Johnathan Xia
The entire concept of nanotechnology seems farfetched. From science
fiction to pop culture, you probably recognize nanotechnology as fleets
of microscopic machines zooming in to fix—or exacerbate—some aspect
of humanity. In actuality, nanotechnology is just a set of tools and devices
that allows us to manipulate things on a scale of less than 100 nanometers. In this strange nano-realm, regular physics goes right out the window; gravity becomes irrelevant and quantum physics kicks in, leading
to new types of materials with unexpected and sometimes revolutionary
properties. Nevertheless, these unexpected properties consequently may
generate unforeseen difficulties in developing this new technology. We
have barely scratched the surface on what nanotechnology can accomplish; however, a certain type of molecule, the carbon nanotube, has the
potential to advance nanotechnology dramatically. Through their unique
properties and myriad of uses, carbon nanotubes are poised to become
the building blocks of the technology of tomorrow.
Nanotubes have a highly unique structure. They are formed from
a graphite-like material called grapheme, thin sheets of carbon atoms
bonded together with alternating single and double bonds, rolled at
specific angles. The rolling angle and radius of the tubes control their
electronic and magnetic properties1. There are three main types of tubes.
The first, called zigzag nanotubes, has carbon atoms bonded in a zigzag
pattern. The blue line shown below traces the zigzag pattern of a string of
carbon atoms running the circumference of the nanotube2:
The second type, armchair nanotubes, forms when the string of carbon atoms running the circumference of the nanotube forms lines that
trace out a pattern resembling the front view of an armchair, as outlined
with the red line in the image below. These tubes are the only types that
behave as metals rather than semiconductors2.
The third type, chiral nanotubes, twists along the cylinder axis, like a
screw. The image below highlights hexagons of carbon atoms that form
an adjacent pattern and twist along the nanotube axis in a right-handed
screw2.
Nanotechnology?
reviewed by Dr. Michael J. Sailor
Carbon nanotubes were discovered back in the 1950s, but there is
much left to learn about their myriad properties and practical applications. Firstly, nanotubes are extremely strong, due to the carbon-carbon
double bonds that stitch them together. Skinny tubes can even be slipped
into fatter tubes, creating extremely strong double-walled nanotubes2.
These complex nanostructures, less than 1/50,000th the width of a human hair, can have a strength one hundred times greater than that of
steel3, leading to applications in automobile, bridge, and aircraft structures, where high strength-to-weight ratios are critically needed. Longer-term prospects for these materials include heavy-duty body armor,
bendable computers and televisions, and even a space elevator3. However,
there remain major drawbacks to using nanotubes as structural components, one being price. A single gram of carbon nanotubes costs over one
hundred dollars3. Until methods are developed to manufacture longer
carbon nanotubes more cheaply, the structural applications will only be
practical in a very limited set of systems.
The unique electrical properties of carbon nanotubes hold promise
for many interesting electronics applications. When the nanotubes are
configured in certain ways, their electrical behavior can act as a switch
between conducting and semiconducting2. A computer chip’s processing
power depends on the number of transistors it has, and transistors made
of carbon nanotubes can be packed over one hundred times more densely
than conventional silicon transistors3, thus offering a wealth of potential for the computer industry. The use of carbon nanotubes in current
technology is limited by the Schottky barrier, which limits the electron
flow between a conductor (i.e. a metal) and a semiconductor2. However,
recent research has proven that the type of metal used in conjunction
with carbon nanotubes greatly affects contact conductivity2. Another
limiting factor resides in manufacture. Manufacturing nanotubes into
these transistors often results in many problems; no one has figured out
how to place the nanotubes in specific orientations onto a high-density
device structure. If this problem can be solved for, carbon nanotubes will
become a keystone of the computer industry
KRISTINA RHIM / GRAPHIC
Carbon nanotubes also have implications for the fields of energy harvesting and energy storage. Today, most photovoltaic solar panels use
the semiconductor silicon to convert the sun’s energy into electricity.
These panels are currently too expensive to be competitive with fossil
fuels. Ongoing research is trying to replace silicon in photovoltaic cells
with carbon nanotubes, with the hope that the cost of the devices can be
reduced significantly4. Once we have all this energy, though, how are we
going to store it so we can use it when the sun isn’t out? The answer may
also lie in carbon nanotubes, which make very good capacitors. A capacitor is a device that stores and releases energy repeatedly, much like a rechargeable battery. Capacitors can be charged and discharged millions of
times, whereas rechargeable batteries degrade after only a few thousand
cycles. This greater cycle life and their faster charging span make capacitors an attractive alternative for energy storage. However, they have two
serious drawbacks. First, they lose their charge quickly, even when not in
use. Second, for a given amount of energy, they are not as lightweight as
rechargeable batteries. A capacitor consists of dual layers of conducting
materials with an insulator placed between them5. The conductors are
typically metal foils, while the storage capacity of a capacitor is directly
related to the amount of electric charge that can be stored on the surface of the metal foil layers. Because carbon nanotubes are so small, as
a whole they haverelatively large surface areas. When incorporated into
metal foils, the resulting increased surface area yields a capacitor with a
much greater charge storage competence5, which translates to a lighter
device. More importantly, research has shown that a nanotube capacitor loses charge at a significantly slower rate than that of a conventional
capacitor, and can be charged more quickly than a rechargeable battery.
These factors have generated a great deal of hope that carbon nanotube
“supercapacitors” will someday replace batteries, leading to instantly rechargeable electronics, electric vehicles with greater range and performance, and more reliable renewable energy systems3.
How about the nanobot, popularly mentioned in sci-fi novels and
movies? These carbon-based microscopic robots could perform all sorts
of manufacturing jobs from the atomic level upward, creating high quality goods at a lower price. They could even be used to perform complicated surgical procedures at the microscopic level. Carbon nanotubes have
a role in making nanobots a reality, as they can create motors. Researchers have already made nanotube “muscles,” relying on the nanotubes’
unique electrical properties6. Picture a twisted rope of nanotubes. When
this yarn is soaked in an electrolyte (any solution with ions in it—for example, salt water) and attached to a battery, the individual tubes expand
and the yarn spins, producing great torque; this makeshift motor is able
to spin objects two thousand times heavier than itself at speeds of almost
six hundred rotations per second6. Another motor formed by nanotubes
is much simpler, consisting of a gold rotor mounted on a nanotube shaft;
because the nanotube is nearly frictionless, the rotor can potentially
reach the frequency of microwaves7. This motor has a multitudeof applications, from stirring solutions to acting as oscillators for cell phones7.
These motors prove that carbon nanotubes are not simply chemical curiosities sitting in test tubes; they can be assembled into useful structures
beneficial to the technology of tomorrow.
Nanotechnology has always seemed light years away; however, even
with the technological barriers of today, carbon nanotubes have much
potential. Who knows, in the foreseeable future carbon nanotubes might
truly permeate every facet of the human race, from the food we eat to the
energy we use. With carbon nanotubes, the possibilities are truly endless.
REFERENCES
1. Kibis, Oleg V. Electron Properties of Chiral Carbon Nanotubes. International Max Planck Research School. Max Planck Society, n.d. Web.
2. Yildrim, Tanner. “Interlinking, Band Gap Engineering, Tunable Adsorption and Functionalization of CarbonNanotubes.” Ncnr.nist.gov. N.p., n.d. Web. 17 Dec. 2012.
3. Perlman, Ben. “10 Uses for Carbon Nanotubes.” Discovery Channel. Discovery Communications, n.d. Web. 17 Dec. 2012.
4. Klinger, Colin. Carbon Nanotube Solar Cells. Plos One. N.p., n.d. Web. 17 Dec. 2012.
5. Stauffer, Nancy. “Saying Goodbye to Batteries.” MIT Energy Research Council : Research Spotlight. Ford-MIT Alliance, n.d. Web. 17 Dec. 2012.
6. Spinks, Geoff. “Show Us Your (carbon Nanotube Artificial) Muscles!” The Conversation. N.p., 14 Oct. 2011. Web. 17 Dec. 2012.
7. Sanders, Robert. “Physicists Build World’s Smallest Motor Using Nanotubes and Etched Silicon.” UC Berkely News. UC Berkeley, 23 July 2003. Web. 17 Dec. 2012.
the workings of
Methylmercury
By Maria Ginzburg
Edited by Ahmad Abbasi
Reviewed by DR. Kathleen Matthews & DR. Saswati Hazra
The ancient Chinese believed
in the body. Mercury simply bonds with these compounds and thus
that mercury
could heal various maladies and
“jumps” from protein to protein and from organ to organ [4, 6].
grant eternal life. China’s first emperor, Qin Shi Huang, was killed after
Most research done on mercury’s effect on the human body has
ingesting mercury pills thought to guarantee immortality, and was then
concerned the compound methylmercury [4]. Methylmercury is a
buried surrounded by a moat of liquid mercury along with his famous
rather toxic mercury compound found in the environment, known
terracotta warriors [1]. During the 15th to 18th centuries, men and
for its neurodevelopmental toxicity in both animals and humans [9].
women plastered themselves, whitened themselves, and, unfortunately,
Because methylmercury is an organic compound, its absorption rate
hurt themselves using various poisons such as arsenic, lead, and, of
and long-term retention are higher than inorganic forms of mercury
course, mercury [2]. Nowadays, mercury is still an important topic for
or elemental mercury, accounting for its ability to cause brain and
many — controversies now circle around mercury in anything from
liver damage upon introduction into the bloodstream [7, 8]. Since
dental amalgams and cosmetics, to tap water and fish [3].
the primary source of methylmercury in humans is through the
Today we know what previous generations did not —
consumption of seafood, the FDA and EPA advise pregnant and
mercury is a toxic metal. Decades of research
nursing women, as well as small children, to limit their
have proven that almost all known forms
consumption of fish [10].
of mercury are dangerous neurotoxins,
Understanding the transport of methylmercury
capable of causing acute and even
requires exploring the role of glutathione in
chronic poisoning [4]. Mercury
the process. Glutathione is the primary
poisoning primarily affects the
intracellular antioxidant designed to protect
kidneys, gastrointestinal tract,
cells from damage, but methylmercury
liver, and central nervous
has an affinity to both glutathione and
system, and is able to easily
some of its components, which include
cross the blood-brain
cysteine residues that contain thiols
barrier [4, 5]. This toxin is
[8]. Upon ingestion of contaminated
also known to have caused
food, the body is introduced to
respiratory, immune,
methylmercury in the form of the
and developmental
toxin bonded to a thiol, usually
complications in humans
the amino acid cysteine [5]. The
and can stop antioxidative
methylmercury is then absorbed into
processes in the body [4, 6].
the bloodstream, which distributes
For these reasons, mercury
approximately 95% of the ingested
has fallen out of favor. Now, it is
amount to the body’s tissues, leaving 5%
quite customary to avoid contact
of the toxin to circulate in the blood [4].
with mercury at all costs; many
According to research, the 95% of the remaining
concerned parents and health-conscious
methylmercury is then deposited in the brain and
C
PHI
BOFA
A
individuals make a habit of avoiding
hair.
Thankfully, hair is a natural excretion route, so the
R
N CHEN/G
purchase or use of any item that contains mercury.
toxin excreted through the hair is not a danger [11]. Overall,
However, what many individuals do not know is why mercury
the mercury concentration of the hair on the scalp ends up to be about
should be avoided. We are aware of the ill effects that might be wrought,
50 times that of the brain, which still ends up with a methylmercury
but why is it that such a simple substance is so dangerously toxic? How
concentration of about five times that of the blood [4]. However,
is it transported throughout the body? Why doesn’t it leave the body
methylmercury does not travel only to the brain and hair or remain in
easily?
the bloodstream; the blood transports methylmercury to the liver as
Here is a basic overview:
well, where a new path begins.
Unfortunately, the human body cannot significantly impede mercury’s
Inside the liver, methylmercury bonds with reduced glutathione to
transport due to loopholes in its physiology and chemical construction.
form a methylmercury-glutathione complex. That complex is then
Mercury has a high affinity to sulfur compounds, which are found in
transported out of the liver into the intestines [4]. There, extracellular
most human organs and proteins, so can be transported very easily
enzymes break the glutathione down into several
PH
IC
amino
acids, including cysteine,
which houses the active site for the methylmercury bond. The methylmercury-glutathione complex
is now a methylmercury-cysteine complex [6]. This new complex is
then mistakenly recognized by the body as the amino acid methionine and
remains undetected. The gallbladder transports the complex back into the blood,
and the complex cycles back to the tissues, mostly entering the neural complex and then
the brain [4]. The processes of exiting through the glutathione pathway and then entering
cells as a cysteine complex explain methylmercury’s continued mobility in the body. While most
methylmercury stays in the body, some excretion of the compound occurs through the feces, albeit in a
minimal amount [4, 6].
The substantial health risk of exposure to methylmercury begs the question: is it possible to increase excretion of this toxic compound? A partial solution is provided by chelation, a process by which certain
chemical agents remove heavy metals from the body, allowing mercury to be drawn out the body in the same way
that it is drawn in [12]. Recall how mercury can travel through the body using the sulfur contained in the body’s
proteins and organs. In the same way, sulfurous chelating agents such as dimercaptosuccinic acid (DMSA) can form
compounds with mercury to be excreted by the body [13]. DMSA is currently one of the most common chelating
agents and is the US Standard of Care for the treatment of various heavy metal
poisonings.
Though some alternative practitioners claim chelation is effective in
treating
various conditions like heart disease and autism, these uses of
the
technique are not largely recognized by the scientific community; it is currently only applicable in the field of heavy
metal toxicity [14].
Methylmercury is highly toxic and unfortunately
much too accessible in today’s modern world.
Even in an industrialized society like that of the
United States, methylmercury poisoning is still
a possibility; the threat is even worse in less
industrialized societies. However, continued research on such toxins ensures
that incidents like the 1951 Minamata
poisoning in Japan and the 1971 Iraq
poison grain disaster will not happen again. Research, awareness,
and action are the only things
that will eradicate future
mercury poisoning. A
R
/G
G
N
TA
REFERENCES
IC
ER
[1] Moscowitz, C. “The Secret Tomb of China’s 1st Emperor: Will We Ever See Inside?” http://www.livescience.com/22454-ancient-chinese-tomb-terracottawarriors.html (2012).
[2] Mapes, D. “Suffering for Beauty Has Ancient Roots.” http://www.nbcnews.com/id/22546056/ns/health/t/suffering-beauty-has-ancient-roots/ (2008).
[3] Mercury in the Environment.” http://www.usgs.gov/themes/factsheet/146-00/ (2000).
[4] Clarkson, T. W., & Magos, L. The toxicology of mercury and its chemical compounds. Critical Reviews in Toxicology 36, http://informahealthcare.com/doi/abs/
10.1080/10408440600845619?journalCode=txc (2006).
[5] Schaefer, J. K., & Morel, F. M.M. High methylation rates of mercury bound to cysteine by Geobacter Sulfurreducens. Nature Geoscience 2, http://www.nature.
com/ngeo/journal/v2/n2/full/ngeo412.html (2009).
[6] Nordberg, G. F., Fowler, B. A., Nordberg, M., & Friberg, L. T. Handbook on the Toxicology of Metals. (Elsevier Inc., 2007).
[7] Kershaw, T. G., Clarkson, T. W., & Dhahir, P.H. The relationship between blood levels and dose of methylmercury in man. Arch. Environ. Health 35, http://www.
ncbi.nlm.nih.gov/pubmed/7189107 (1980).
[8] U.S. Environmental Protection Agency. “Mercury.” http://www.epa.gov/hg/effects.htm.
[9] Carvalho, M. C., Nazari, E. M., Farina, M. & Muller, Y.M.R. Behavioral, morphological, and biochemical changes after in ovo exposure to methylmercury in chicks.
Toxicological Sciences 106, http://www.ncbi.nlm.nih.gov/pubmed/18684774 (2008).
[10] “’Seeing’ Mercury Methylation in Progress.” http://www.ssrl.slac.stanford.edu/research/highlights_archive/hg_methylation.html (2009).
[11] “Excretion.” http://www.forcon.ca/learning/excretion.html.
[12] Flora, S. J.S., & Pachauri, V. Chelation in Metal Intoxication. Int. J. Environ. Res. Public Health 7, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2922724/
(2007).
[13] Miller, A. L. Dimercaptosuccinic acid (DMSA), a non-toxic, water-soluble treatment for heavy metal toxicity. Altern. Med. Rev. 3, http://www.ncbi.nlm.nih.gov/
pubmed/9630737 (1998).
[14] Rasnake, Jarrod. “Chelation Therapy.” http://faculty.virginia.edu/metals/cases/rasnake1.html.
P
lastics:
AB
C
lessing and a
By: Nilay Shah, Edited By: Kenny Xu
urse
Reviewed By: Dr. Hari Khatuya, Dr. Simpson Joseph, Dr. Gang Chen, Dr. Haim Weizman
Boeing’s new 787 Dreamliner…
Nylon clothing…
Quick-dry Paint…
Bubble-gum…[1]
What do these seemingly incongruous items have in common?
Plastic! All are composed of plastic polymers. Plastic’s popularity is due to its strength, durability, resistance to corrosion, and lightweight character. That’s not all; it can imitate and replace metal, wood,
glass, china, stone, cloth, rubber, jewels, glue, cardboard, varnish,
and leather. Plastics are found everywhere, from mundane objects
such as clothing, car parts, electrical insulation, and heating insulation to more exclusive articles like the combat helmets used in the
military. It has even become instrumental in space exploration [2].
Let’s start with the basics. Plastics are made of polymers, large molecules that can consist of hundreds of thousands of atoms, distinguishing plastics from other materials. Monomers, single molecules, join
together to construct a polymer chain in a process known as polymerization. Then, the chains connect to form networks — chains linked
to each other at various spots — in a complex, mesh-like structure [3].
Plastic has a very long history, breaching all seven continents of the
world and creating multibillion-dollar corporations. Hundreds of years
before the first synthetic plastics were developed, natural substances such
as tree saps and animal horns were used as plastic materials. In 1869, John
Wesley Hyatt revolutionized the world with the invention of celluloid, the
first synthetic plastic. He stumbled upon celluloid while searching for an
inexpensive substitute for the ivory in billiard balls. It consisted of cellulose nitrate “plasticized,” or softened, by camphor. Versatility of this new
creation led to its use not only in billiard balls but also in eyeglass frames,
combs, shirt collars, buttons, dentures, and photographic film. For forty
years, celluloid remained the only prominent invention in the plastic
industry. However, improving upon recently developed techniques in
the field, American chemist Leo Hendrik Baekeland developed phenolformaldehyde, dubbing it Bakelite, in 1909. It was the first plastic to be
made entirely of synthetic ingredients. Baekeland’s invention “marked
the true beginning of the plastic industry” known today [2]. 8 | JOURNYS | SPRING 2013
LINH LUONG/GRAPHIC
The word “plastic” comes from the Greek word “plastikos,” meaning “able to be molded” — a suitable derivation since plastics’ defining
characteristic is that they “can be molded into desired forms, drawn into
fibers (threads), stretched, and/or bent” (Goodstein). Plastics are made
from petroleum (crude oil and natural gas), and can be divided into two
categories, thermosets, and thermoplastics. Thermosets are highly infusible and initially soften when heated. However, if heat is applied for an
extended period, they will set, or harden. Once done, these plastics can
withstand temperatures of up to 500° F (260° C) before singeing. This
is due to cross-linking, in which the molecules link together between
chains. On the other hand, thermoplastics harden only when they are
cooled and do not undergo cross-linking. As a result, they will soften
or even melt at temperatures around 200° F (93° C). Most types of plastics also contain additives, which are added to attain a certain characteristic in the final product. These additives can make plastics can be
used to make plastics more malleable or flame retardant [2]. Now that we have discussed the popularity of plastics, I would like
you to imagine this: A wandering albatross soars over the calm ocean
waves, oblivious to the danger that lurks beneath. After many miles, she
spots a squid and dives down into the water. Snapping it up, she begins
the long journey back to her nest; little knowing that the “food” she
carries in her mouth will lead to the death of her chick. This scene is
one of many that take place due to the twenty billion pounds of plastic that is deposited in our oceans annually, resulting in the death
of over 1,000,000 seabirds and 100,000 marine animals every year.
However, this only affects animals in the ocean, right? Why should
humans care? In reality, this negatively affects the entire global ecosystem due to biomagnification. This dilemma arises at the bottom of the
food chain. Zooplankton have been known to consume microscopic fragments of plastics, which can leach harmful chemicals like styrene trimer
and bisphenol A into their bodies. Moreover, petroleum-based plastics
LINH LUONG/GRAPHIC
concentrate other hydrophobic chemicals like PCBs and DDT, having
levels up to one million times higher than the surrounding seawater because they are normally diluted in the ocean. As these chemicals travel
up the food chain they become increasingly concentrated because animals’ digestive systems are not capable of breaking them down (figure 1).
Consequently, this affects humans, who are at the top of the food chain.
Even in light of these problems, plastics are used so prevalently because there are many desirable characteristics of petroleum-based plastics. Firstly, they are recyclable — but this comes at a high cost. Also,
Plastics can be burned, with the possibility of harnessing the energy to
generate electricity. However, this releases toxic fumes into the environment. Durability is another two-sided coin. While plastics can handle
the wear and tear of daily use, and will not disintegrate under various
weather conditions, once discarded they will stay in the environment
for hundreds to thousands of years; they make up 20% of the volume
in today’s landfills! Lastly, oil prices are constantly on the rise and this
correlates to higher manufacturing costs for petroleum-based plastics.
This problem seems too vast to solve. Plastics are saturated in our lives; therefore, eradicating them is not a viable solution. For that reason, many researchers have engaged in finding suitable alternatives to petroleum-based plastics: eco-plastics.
Most eco-plastics can be categorized as either degradable, biodegradable, or compostable. In degradable plastics, the chemical structure changes because of particular environmental conditions including heat, moisture, and/or UV exposure. Large scraps of plastic are
broken into smaller fragments, often microscopic, but can still have a
drastic impact on the environment. On the other hand, microorganisms naturally break down the molecular components of biodegradable plastics. However, there isn’t a set time for biodegradation, and
toxic chemicals may be produced from this process. Lastly, compostable
plastics are also biodegradable, further generating carbon dioxide, water, inorganic compounds, and biomass at the same rate as cellulose
(paper). In the final product, a compostable plastic should have completely disintegrated without any production of toxic chemicals [4].
The first type of eco-plastic is bio-plastic. Bio plastics are made up
of biodegradable plastics and bio-based plastics. Biodegradable plastics,
such as Petroleum-based Oxo-biodegradable plastics, are made from fossils fuels, which microorganisms will decompose. They contain a “prodegradant” additive, which can activate and quicken the degradation
process. These plastics undergo a reaction with oxygen via daylight, heat,
and/or mechanical stress and break down into microscopic fragments.
Then, these smaller oxidized molecules undergo biodegradation. Alternatively, bio-based plastics are made from biomass or renewable resources and may or may not be decomposable. Plant-based hydro-biodegradable plastics are plastics that are both bio-based and biodegradable [5].
Additionally, some companies that are said to be eco-friendly are devising new types of plastics. ECM Biofilms is developing petroleum-based plastics containing “microbe-attracting pellets” that will result in a faster degradation time at the landfills.
Novomer is developing a plastic using carbon dioxide and carbon
Figure 1[7]
monoxide (reacted with liquid metal) that would not only eradicate detrimental gases from the air but also be biodegradable [6].
The ubiquitous plastic presents a serious threat to the globe, and scientists have just begun understanding its effects. Developing eco-plastics
is a new area in science in which new discoveries are being made every
day — one day, the conventional plastic may be no more. Perhaps, after reading this article you decide to take the first step and revolutionize your lifestyle, vowing never to use a plastic product again. If not, at
least you will have become more conscious of the world around you.
REFERENCES:
[1] O’Brien, K. “In Praise of Plastic.” http://www.boston.com/bostonglobe/ magazine/articles/2008/09/28/in_praise_of_plastic (2008).
[2] Abdullah, M. G. et al. Plastics. Compton’s by Britannica 6, http://www.britannica.com/
EBchecked/topic/591750/thermosetting-plastic(2009).
[3] Goodstein, M. Plastics and Polymers Science Fair Projects (Enslow Publishers, Inc.,
Berkeley Heights, 2004).
[4] “Degradable & Biodegradable Bags.” http://www.packagingknowledge.com/ degradable_biodegradable_bags.asp (2009).
[5] Tokiwa, Y., Calabia, B. P., Ugwu, C. U., & Aiba, S. Biodegradability of Plastics. Int. J. Mol.
Sci. 10, http://dx.doi.org/ 10.3390/ijms10093722 (2009).
[6] Layton, J. “What are eco-plastics?” http://science.howstuffworks.com/environmental/
green-tech/sustainable/eco-plastic.htm (2009).
[7] “E-Learning, E-Tutoring, School Education Support & Online Education, Digital Learning, Smart Learning.” http://www.extramarks.com (2012).
HIGH TEMPERATURE SUPERCONDUCTORS
by Lilia Tang
edited by Kevin Li
reviewed by Dr. Benjamin Grinstein and Dr. Aneesh Manohar
Imagine a computer that never has to be re-charged. The computer
would never turn off randomly, and no one would ever have to worry
about losing work from a low battery. At most, one would only have to
plug the computer in once in a while and it would be ready to run for
eternity. Is it possible for an electrical current to flow forever? This is a
property of superconductors: to have current flow with zero resistance.
Dutch physicist Heike Kamerlingh Onnes was working with mercury at
extremely low temperatures when he discovered that at 4.2 K, all resistance disappeared. The temperature at which the resistance disappears
is known as the superconducting or critical temperature Tc. However,
because they operate only at such low temperatures, superconductors
do not have many everyday uses [1]. Currently, physicists working with
superconductors are trying to develop alloys of metals with higher superconducting temperatures, the highest being 135 K so far, under normal
pressure.
KATHERINE LUO / GRAPHIC
But why do superconductors only work at extremely low temperatures? The Bardeen-Cooper-Schrieffer (BCS) theory explains how superconductivity works. Resistance in metals occurs because the electrons
passing through them are scattered due to imperfections [2]. Electrons
passing through the lattice, or the structure of the superconductor, overcome repulsion to pair up and pass through the material without creating resistance. Quasi-particles called phonons, which are excited elastic
organizations of atoms in solids and are also known as lattice vibrations,
are necessary for this to work.
One may wonder how the electrons can overcome this repulsion. The
main reason is that they are a part of a lattice of positive atoms. When
the electrons pass through, the atoms are shifted slightly towards the
electron, so when another electron comes by, its trajectory will change
because of this shift, leading to each electron pulling towards each other.
This pairing up of electrons is called a Cooper pair [3].
These Cooper pairs have different properties than single electrons.
Single electrons are fermions, which have half-integer spins, and must
follow the Pauli Exclusion Principle, which implies that two electrons in
a single atom cannot have the same quantum numbers [4]. Cooper pairs,
on the other hand, are regarded as composite bosons, have integer spins,
and are able to condense into the same energy level [3][5]. They have
slightly less energy than two free electrons and create an energy gap. Cooper pair collision can create slight resistance. But when the temperature is
lower than the energy gap, the resistance decreases to zero.
However, BCS theory does not explain how high-temperature superconductors work. This is because generally at temperatures over 30 K,
the electrons cannot pair up because the entropy (disorganization) is too
high in the lattice. People still do not completely understand how hightemperature superconductors work. There are many theories, but none
of them are entirely correct. Many of the materials used to superconduct at high temperatures are not metals, but ceramics. Because different
compounds of ceramics tend to function differently, there is no universal
theory of how they work. However, scientists have found theories on how
particular types of high-temperature superconductors work [3]. For example, copper oxides are known as a class of superconductors.
Copper is known to be an effective conductor, so why not try
to use copper alloy, or a cuprate, as a superconductor? Yttrium barium
copper oxide (YBCO) was the first superconductor to maintain superconductivity at a higher temperature than nitrogen’s boiling point (77 K),
with a Tc of 90 K, making it a high-temperature superconductor. It has
the chemical formula YBa2Cu3O7−x and is created by heating metal carbonates to 1000 K to 1300 K. The reaction is represented by the following
chemical formula:
As seen in Figure 1, YBCO is a crystalline structure with copper oxide planes and chains, and layers of BaCuO3 and YCuO3. The copper oxide planes and chains, however, have
empty spots in the lattice that would
be for oxygen, allowing for the oxidization of the copper oxide, which enables the compound to superconduct
[6].
However, yttrium is not that easy
to obtain. The main source of yttrium is from a type of clay reserve in
China, combined with other heavy
rare earth metals. Since it is found
impure, people must use expensive
processes to extract the yttrium.
Bismuth strontium calcium copper
oxide (BSCCO) is more commonly
used for electromagnets and motors
because it is more accessible and has
Figure 1
a higher Tc[7].
Another recently found superconductor is magnesium diboride (MgB2), which has a Tc of 39 K. Although it may seem extremely
cold compared to other superconductors like YBCO, its ingredients are
more readily available than YBCO’s. Like YBCO, MgB2 is a crystalline
structure with hexagonal layers of boron atoms between layers of magnesium atoms, with each magnesium atom being between the centers of the
hexagons, as shown in Figure 2. This is actually quite similar to the simple
structure of graphite, shown in Figure 3.
Figure 2
Figure 3
REFERENCES
[1] Whittingham, M. S. “Preparation, Structure, and Properties of a High-Temperature
Superconductor.” http://imr.chem.binghamton.edu/labs/super/superc.html (1995).
[2] Eck, J. “Superconductivity Explained.” http://www.superconductors.org/oxtheory.htm
[3] Orzel, C. “How Do Superconductors Work.” http://scienceblogs.com/
principles/2010/08/03/how-do-superconductors-work/ (2010).
[4] Nave, R. “Pauli Exclusion Principle Applications.” http://hyperphysics.phy-astr.gsu.edu/
hbase/pauli.html#c2
[5] Nave, R. “BCS Theory of Superconductivity.” http://hyperphysics.phy-astr.gsu.edu/
hbase/solids/bcs.html#c1
[6] “Yttrium Barium Copper Oxide - YBCO.” http://www.ch.ic.ac.uk/rzepa/mim/century/
html/ybco_text.htm
[7] “BSCCO.” http://www.magnet.fsu.edu/magnettechnology/research/asc/research/
bscco.html (2012).
[8] Preuss, P. “A Most Unusual Superconductor and How It Works: First-principles
calculation explains the strange behavior of magnesium diboride.” http://www.lbl.
gov/Science-Articles/Archive/MSD-superconductor-Cohen-Louie.html (2002).
The Quest for
Immortality
edited by Eric Chen
/ GR
AP
H
IC
by Varun Bhave
SARAH EKAIREB
MgB2 superconductivity is
not completely explained by
BCS theory, but it is strongly
related. MgB2 is commonly considered as a high-temperature
superconductor because it has
the highest Tc of a BCS superconductor. BCS theory assumes
that the coupling of the lattice for the pairing of electrons
should be equal to the coupling
of a single electron emitting and
re-absorbing a phonon [8]. In
MgB2, these values are different,
so how does it work? This can be
explained by the type of sigma
and pi bonds in the structure.
In some covalent bonds, the
electron density is symmetrical
about the axis line connecting
the nuclei (internuclear axis).
This means that the internuclear
axis goes through the region of
the electrons’ orbitals. These
CHRISTINA BAEK/ GRAPHIC
bonds are called sigma (σ)
bonds. When orbitals are perpendicular to the internuclear axis, it is a
pi (π) bond. MgB2 and graphite have strong σ bonds in the planes and
weaker π bonds between the planes. However, unlike graphite, MgB2 has
boron, which does not have as many valence electrons as carbon. Not all
the sigma bonds are filled in the boron layers, so lattice vibrations are
stronger because the structure of the lattice is weaker, which results in
stronger electron pairs in the planes [8].
Because there are many different types, high-temperature superconductors still remain much of a mystery. We do not have a universal
theory for them, because they generally are made up of layers of different
atoms, each of which has its own properties. For example, YBCO’s superconductivity is based on the interesting oxidization of the copper oxides,
but this is only relevant to the specific structure of YBCO. The materials
used in high-temperature superconductors are generally hard to obtain
since many of them require lanthanides, which are difficult to extract
and purify. Even today, the critical temperature is still too low for general purposes, since high-temperature superconductors still have to be
refrigerated with liquid nitrogen. Hopefully someday inexpensive roomtemperature superconductors will be developed, which will increase the
efficiency of many circuits and electrical appliances.
The New York Times reported on May 5, 1933 the death
of Li-Ching Yun, a Chinese herbalist and military instructor [1]. Li
claimed to have been born in 1736, theoretically making him 197
years old; he attributed his longevity to maintaining mental tranquility and “sit[ting] like a tortoise, walk[ing] sprightly like a pigeon,
and sleep[ing] like a dog” [2]. Several years earlier, a professor at
Minkuo University had allegedly found records indicating, even more
startlingly, that Li was born in 1677 and had been sent messages of
congratulations from the Chinese government on his 150th and 200th
birthdays. Many of the oldest men in Li’s neighborhood asserted
their grandfathers knew him as children and that he was, even then, a
grown man. Numerous other Chinese military and medical references
seemingly corroborate Li’s existence, career, and longevity.
Today, many discount Li’s claim as ludicrous; the oldest
confirmed human being was Jeanne Calment, a French woman who
was 122 when she died in 1997 [3]. However, particularly in industrialized nations, better scientific understanding of the human body and
medicine, improved diets, and higher quality of life have contributed
to a dramatic increase in human life expectancy. Indeed, a 2009 study
in The Lancet journal estimated that half of babies born today in developed nations will live to be 100 years old. The study also analyzed past
life expectancy trends; researchers concluded that life expectancy had
been rising since the 1840s and showed no signs of maxing out. In fact,
the likelihood of surviving past 80 years old has doubled in both sexes
since 1950 [4]. The continuous rise in life expectancy has introduced
into scientific discourse the possibility of functionally immortal humans who, absent unnatural death, could survive forever. This article
specifically examines the innovative possibilities of life-extension substances, cryonics, and the more science fiction-like theories of mind
uploading and advanced gene therapy.
Apart from basic and well-known life extension mechanisms, including caloric restriction, specific diets, and certain drug
supplements, enzymes like telomerase and the chemical resveratrol
have been considered as possible life-extenders. Resveratrol, a substance produced by several plants in response to pathogens, has been
shown to significantly retard the aging process in mice [5]. Telomerase,
an enzyme that helps maintain protective caps on the ends of chromosomes, is the more promising of the two. Normally, cells will divide
until they reach the Hayflick limit, at which point division stops. This
is because the telomeres paired with each cell’s DNA shorten with each
division until they reach the critical length. With artificially increased
amounts of the enzyme, any cell can undergo mitosis unbounded, preventing numerous health problems arising from the death of cells. However, telomerase also has the potential to promote the tumorigenesis at
the root of cancer, which is likewise caused by the unchecked division of
cells [6].
Furthermore, growth hormone therapy has been found to improve muscle mass composition, heart health, and bone density without
major side effects in animals [7]. While all of these developments have
the potential to slow aging, they do not truly ensure biological immortality.
The arguably most developed field in theoretically ensuring immortality is cryonics, the expensive preservation of medically
dead humans (either just the brain or the entire cadaver) at extremely
low temperatures based upon the premise that healing or revival may
be possible later. While current technology cannot resuscitate such
individuals, recovery will theoretically be possible from some advanced
future technology that will change the current medical definition of
death. While the largest cryonics institution today is the ALCOR Life
Extension Foundation, it has only administered the procedure on 115
people to date [8].
Cryonics is based on an accepted assumption, that much
of a person’s memory, identity, and personality is stored in parts of
the brain that do not require continuous brain activity to survive and
can be revived after the cessation of neural activity (i.e. legal death)
[9]. Skeptics of cryonics rather highlight the infeasibility of actually
restoring brain activity into a form of meaningful expression in a living
human being. Numerous unavoidable factors, like cell damage from
whole-body freezing and lack of oxygen from blood circulation between
“death” and a cryonics procedure, make revival impossible with current
medical knowledge. Proponents of cryonics hope that advanced tissue
regeneration and oxygen-debt, freezing, and past cryoprotectant toxicity
reversals may be possible, especially through millions of nanorobots
that would restore healthy cell structure and chemistry [10]. More futuristic revivals of cryonic brains would incorporate some sort of “mind
transfer,” whereby the brains would be scanned by a computer and their
information integrated with an entirely new body.
There are several even more far-fetched possibilities for immortality, which become increasingly abstract and hypothetical. The
first is mind uploading, a hypothetical process of copying and transferring a brain to a non-biological entity, perhaps a computer or, as
recently proposed by Russian scientists, a humanoid robot [11]. Such
uploading would both “back up” the brain if the body suffered injury
and allow “humans” to exist within a significantly more resilient robotic
or virtual reality form. This would theoretically detach the human existence from the limitations of the body, potentially allowing for increased
computational capacity and lower the risks of physically dangerous
activities like space travel. However, copying supercomputers would
have to ensure a perfect mimicry with the functions of the real brain
being transferred. Some research is being done in this field; the brain
structures of a fruit fly and roundworm species have been simulated to
some degree [12]. In addition, IBM and a Swiss university launched the
“Blue Brain” initiative in 2005, which aims to simulate parts of mammalian brains; the program has had some success in modeling rat neural
pathways [13].
The final theory of immortality discussed here is gene modification, which has already been studied extensively for its application
in replacing mutated or deficient genes with normal ones. However, it
has been proposed that ageing could be theoretically almost entirely
stopped by preventing the activation of genes that manifest themselves
later in life and chemically advance the ageing process. This would ide14 | JOURNYS | SPRING 2013
ally “fool” the body into believing itself younger than it actually is [14].
To succeed in the quest for immortality (or something very
close to it) would be the crowning achievement of medicine. The science today is rudimentary at best, but developing human biological
immortality would help assuage the deeply rooted human desire to
avoid dying. However, the exponential extension of human existence
could lead to overpopulation and economic repercussions. Ultimately,
philosophers and religious figures will debate the mind-body separation, the ethics of resurrection, and the assumption that death is to be
feared. However, scientists and the public, even 500 years after Spanish
explorer Ponce de Leon searched for the “Fountain of Youth,” continue
to be fascinated by the idea that death can be conquered.
REFERENCES:
[1] “Li Ching-Yun Dead; Gave His Age As 197.” The New York Times. 6 May 1933. Web.
http://select.nytimes.com/gst/abstract.html?res=FA0915FE3E5C16738DDDAF0894
DD405B838FF1D3
[2] “Tortoise-Pigeon-Dog.” TIME. 15 May 1933. Web. http://www.time.com/time/magazine/article/0,9171,745510,00.html
[3] Whitney, Craig. “Jeanne Calment, World’s Elder, Dies at 122.” 5 August 1997. New York
Times. Web. http://www.nytimes.com/1997/08/05/world/jeanne-calment-world-selder-dies-at-122.html
[4] “Half of babies ‘will live to 100.’” BBC News. 2 Oct. 2009. Web. http://news.bbc.co.uk/2/
hi/health/8284574.stm
[5] Baur et al. “Resveratrol improves health and survival of mice on a high-calorie diet.”
Nature, Nov. 2006. Web. http://www.ncbi.nlm.nih.gov/pubmed/17086191
[6] De Magalhães, João Pedro and Olivier Toussaint. Rejuvenation Research. July 2004. pgs 126-133. Web. http://online.liebertpub.com/doi/
abs/10.1089/1549168041553044
[7] Gustad, Thomas and David Khansari. “Effects of long-term, low-dose growth hormone
therapy on immune function and life expectancy of mice.” Mechanisms of Ageing
and Development (Vol. 57, Issue 1), Jan. 1991. Web. http://www.sciencedirect.com/
science/article/pii/004763749190026V
[8] ALCOR Life Extension Foundation. Web. http://www.alcor.org/cases.html
[9] Guyton, Arthur. “The Cerebral Cortex and Intellectual Functions of the Brain.” Textbook
of Medical Physiology (7th ed.). W. B. Saunders Company, 1986. pg. 658
[10] Freitas, Robert and Ralph Merkel. “A cryopreservation revival scenario using
MNT.” Cryonics (ALCOR Life Extension Foundation), 2008. Web. http://www.alcor.
org/cryonics/cryonics0804.pdf
[11] O’Neil, Lauren. “Human immortality could be possible by 2045, say Russian scientists.”
CBC News, 31 July 2012. Web. http://www.cbc.ca/news/2012/07/human-immortality-could-be-possible-by-2045-say-russian-scientists.html
[12] Erdos, Paul and Ernst Niebur. “Theory of the locomotion of nematodes: Control of
the somatic motor neurons by interneurons.” Mathematical Biosciences, Nov. 1993.
Web. http://www.ncbi.nlm.nih.gov/pubmed/8260760
[13] Herper, Matthew. “IBM Aims To Simulate A Brain.” Forbes. 6 June 2005. Web. http://
www.forbes.com/technology/sciences/2005/06/06/cx_mh_0606ibm.html
[14] Dawkins, Richard The Selfish Gene. New York: Oxford University Press, 2006.
pgs. 41–42.
i can
SEE
By: Harshita Nadimpalli with My
TONGUE
Edited By: Emily Sun
There is a multitude of individuals in the world who are born
without vision, and countless others are met with terrible accidents
that leave them blind. Over time, these people learn to live their lives
again as they recover from the trauma and depend on their newly
heightened senses of smell, hearing, or touch. They learn to read
their favorite books by using Braille, learn to know what their dinner
is through the nuances of the odors of the various ingredients in their
meals, and learn to cross busy intersections using the subtleties of
footsteps and the sounds of revving car engines. All of this is possible
due to the brain’s incredible ability to form new neural connections
after being damaged and to develop its own system of reorganization
in order to recover [1]. This phenomenon is known as neuroplasticity.
Neuroplasticity is thought to be an evolutionary mechanism
that compensates for a lost sense by increasing the acuteness of others.
In the 1960s scientists began testing alternate methods that would enable
people to become independent of their eyes for visual input [2]. Then, a
scientist named Paul Bach-y-Rita developed the idea of using the tongue
as a surface to transmit visual information to the brain. Inspired by a
stroke that his father had suffered, Bach-y-Rita constructed a primitive
version of the technology that he would later develop. He began with
a 20-by-20 array of metal rods in the back of an old dentist’s chair that
allowed people who sat in the chair to see images when the rods, which
transmitted electrical impulses, were touched to their backs [3]. This
experiment yielded results of great accuracy, proving that the sense of
touch could indeed be used to substitute for the function of the eye.
Bach-y-Rita then decided to make a switch that would prove to be
groundbreaking; he began to focus on stimulation of touch receptors on
the tongue instead of stimulation of those on the skin. Although Bach-yRita died in 2006, his team of researchers at the University of Wisconsin
continues to work on and further the legacy he left behind. The latest
equipment they have developed is a small mouthpiece that is placed
against the tongue, which allows a person to see without their eyes [4].
So how exactly does this system work? The tongue-stimulation
device, called the Tongue Display Unit, or TDU, has a camera attached
to it which functions as the surrogate seeing-eye of the device. The
system then translates the images detected by the camera, which may
include colors or movements, into a series of electrical impulses
through the small square of 144 electrodes that is placed against the
tongue. These electrical impulses trigger the sensitive touch receptors
on the tongue, and are then conveyed to the nervous system as neural
impulses [4]. These neural impulses are finally perceived as sensory
information by the brain and converted to images as a substitute for
vision, and the person is able to “see” the figures and pictures that the
camera is seeing. The whole process works in a very similar manner to
the process through which people with regular vision see; the tongue,
rather than the optic nerve in the eye, receives energy in the form of
an electrical impulse, and taste receptors on the tongue, rather than
photoreceptors in the eye, eventually transmit information to the brain.
Although more than enough electrical impulses are applied to
the tongue, they do not contain nearly enough voltage to harm a person.
Researchers have found that about 50 hours of practice with the TDU are
needed for a person to become familiar and comfortable with the device [5].
It is important to understand why the tongue is a superior
receptor to other options, such as the skin on a person’s fingertips, in
terms of providing an interface for visual input. First, the tongue consists
of an extremely high density of nerve fibers, receptors, and sensors that
are incredibly sensitive to touch and far more closely packed together
than those on the surface of the skin. Second, each individual taste
bud has a pore that opens out to the surface of the tongue and enables
molecules and ions (from the electrical currents of the TDU, in this
case) taken into the mouth to reach the receptor cells inside. Third,
the tongue is coated in saliva, a highly conductive fluid that is ideal
for electrical impulses to be carried in, which greatly contributes to
the efficiency of the TDU. Furthermore, inside the brain, large parts
of the cerebral cortex, which plays a crucial role in sensory input and
perception, are devoted to the sensory perception of the tongue so
humans can taste their foods and distinguish between edible foods
and potentially harmful or spoiled foods that could cause them harm
[5]. Also, electrical stimulation of the tongue is easier to detect than
the electrical stimulation of a fingertip; only 3% of the voltage needed
for the fingertip is needed for the tongue [6]. As a result, the tongue
is an ideal candidate for the transmission of visual input to the brain.
The use of TDU and similar methods are, of course, extremely
beneficial to individuals whose vision is impaired, as it allows them to
see in a manner that that they probably never thought was possible.
However, this technology can also be very useful in many professional
fields. For example, Navy SEALS worked with Dr. Bach-y-Rita to
create a system based on the TDU that would allow the SEALS to see
infrared images though their tongues in dark or clouded conditions
underwater. Bach-y-Rita also worked with NASA to create sensors for
astronauts to feel things outside of space suits while in orbit, and also
with the air industry to create technology that could alert pilots to other
planes or incoming missiles before their eyes register the threat [7].
The TDU has evolved since its conception. The Minnesota-based
company Wicab Inc., founded by Bach-y-Rita in 1998, has created a vision
device called the BrainPort, which is based on the TDU prototype. Sale of
the BrainPort V100 has been recently approved in the European Union
in March 2013, and Wicab has been trying to make the device available
for those who cannot afford it. However, the FDA has not yet approved
the device, and thus it is not being sold in the United States. The practical
functions of this new sensory substitution technology, including its ability
to help compensate for the loss of normal eyesight and to aid certain
professions, make it a valuable tool in a constantly advancing society.
REFERENCES
[1] Bach-y-Rita, P., Kercel, S.W. Sensory substitution and the human-machine
interface. Trends in Cognitive Sciences 7, 541-546 (2003).
[2] Bach-y-Rita, P., Danilov, Y., Tyler, M. & Grimm, R. J. Late human brain
plasticity: vestibular substitution with a tongue BrainPort humanmachine interface. Plasticidad y Restauración Neurológica 4, http://www.
medigraphic.com/pdfs/plasticidad/prn-2005/prn051_2f.pdf (2005).
[3] Bains, S. “Mixed Feelings.” Wired 15, http://www.wired.com/wired/
archive/15.04/esp.html?pg=2&topic=esp&topic_set= (2007).
[4] Weiss, P. “The Seeing Tongue.” ScienceNews 160, 140 (2001).
[5] Phillips, J. “The Brain: The Real Secret of Alternate Sensory Technology.”
Proquest Discovery Guides, http://www.csa.com/discoveryguides/
sensory/review.pdf (2011).
[6] Bach-y-Rita, P., Kaczmarek, K.A., Tyler, M.E. & Garcia-Lara, J. “Form
perception with a 49-point electrotactile stimulus array on the tongue: A
technical note.” Journal of Rehabilitation Research and Development 35,
427-430 (1998).
[7] Abrams, M. “Can You See With Your Tongue?” Discover Magazine, http://
discovermagazine.com/2003/jun/feattongue/article_view?b_start:int=2
(2003).
REBUILDING the BRUISED BRAIN
Discovery of a Novel Biomaterial in Nanomedicine
A
by MAXINDER S. KANWAL
edited by JENNY LI
group of soldiers clad in camouflaged uniforms prepare to hit
Despite costing the U.S. an estimated $76.5 billion per year in direct
the road for yet another grueling day in the field. Their mission: track and indirect medical costs [4], treatments for TBIs are largely ineffective
down the terrorists who pose a constant threat to the local population. and lead to complications such as secondary injuries via necrosis.
A dispatch for the 1st Platoon arrives and the soldiers quickly mount Presently, doctors cannot help a patient recover fully from TBI. Surgeons
their equipment, salute the commanding officer, and board the armored can only attempt to reduce further damage by releasing the pressure that
vehicle. Moments after they disappear into a cloud of dust, a loud builds up inside the skull through surgery and drainage of excess fluid
explosion thunders through the air. As the dust begins to settle, the when the injury is still fresh, as they did for Congresswoman Gabby
aftermath of a powerful improvised explosive device (IED) fills the scene. Giffords after she was shot in the head [5]. The most appalling fact about
A few human bodies squirm in pain while others lie motionless on the TBI is that, to this day, the Food and Drug Administration has yet to
bloody dirt road. One unconscious soldier, with a dreadful injury to his approve a drug that can effectively treat the ailment [3].
head, is rushed to the nearest hospital. The staff in the emergency ward
So, what are potential remedies currently available to treat TBI? One
knows he will never lead a normal life again; he is the victim of an all adopted therapeutic approach by doctors is to use stem cells to replenish
too common traumatic brain injury (TBI). Sadly, every five seconds, the loss of neurons in the brain. Over the past decade, there has been a
someone in the world is affected by TBI, an occurrence that exceeds the dramatic surge in stem cell research. Stem cells can morph into almost any
combined frequency of HIV/AIDS infections, spinal cord injuries, and type of cell in the human body (neurons, blood cells, muscle cells, etc.)
multiple sclerosis and breast cancer diagnoses [1].
and provide the first hope for recovery from TBI. Unfortunately, even
The brain is one of the most important human organs consisting of though stem cells can replace individual cells perfectly, the brain is not
an interconnected cellular network (figure
simply “individual cells.” All brain cells
1A). However, injury to this complex structure
or “neurons” are intricately connected
different from that occurring in other parts
with each other via specialized structures
of the body. For example, unlike dying skin
called “synapses”. When neurons die, the
cells that are continuously replaced, damaged
multitudes of connections associated
brain tissue deteriorates further (figure 1B).
with those neurons are also lost. With
Typically, the human brain can maintain
the loss of connections there is a loss
normal function throughout an individual’s
of communication; with a loss of
life. However, if the cells die prematurely by
communication there is a loss of brain
external injury, in a process known as necrosis,
function. For stem cells to replenish lost
they cannot grow back. A month to one year
neurons, the connections of the surviving
later, this deterioration continues to worsen.
neurons need to grow across a vast fluidSoon the site of even mild brain injury expands,
filled chasm in the brain and make new
leaving a gaping, fluid-filled hole in the head of
connections, or synapses. However, they
an otherwise normal-looking individual (figure
can never fully replace the connections
1C) [2].
belonging to those lost neurons.
The human brain consists of some 100
Therefore, there is still a need to conduct
billion cells called neurons that are interdecade’s worth of research to figure out
connected by crisscrossing “highways” on
various specifications that go along with
CAROLYN CHU/GRAPHIC
which electrical signals travel. These signals
the use of stem cells to treat TBI. For
code for every action and thought we experience. In TBI, neurons die, example, what types of precautions must be taken to prevent the onset
often due to edema (swelling of the brain) or ischemia (reduction in of an autoimmune response that kills all of the cells foreign to the body.
blood flow to the brain). Permanent brain damage from such an injury A safe and efficacious remedy for TBI continues to elude today’s medical
leads to an impairment of numerous vital functions, such as muscle community [6].
control and memory [3]. To get a sense of the damage caused by TBI,
After years of research, Jiasong Guo and Ka Kit Leung, at the
imagine a vast island, like Manhattan, buzzing with activity to create University of Hong Kong may have crafted a solution to this dire
unique products that can be exported to other parts of the world. The problem. Peering into the brain at a molecular scale, they have affected
city is analogous to a region of the brain, as both contain units (people change on a macroscopic scale. Through the domain of nanomedicine –
or neurons), each responsible for performing a certain function. The a new, promising approach to cure diseases – these two scientists have
occurrence of a severe brain injury is the equivalent to the effects of a fabricated a new biomaterial that may present a solution for TBI. Termed
magnitude 9 earthquake on the Richter scale. At the epicenter and for “self-assembling peptide nanofiber scaffold,” or SAPNS for short, their
many miles beyond, buildings crumble, highways tear apart, and bridges newly developed nanobiomaterial assists neurons in recovering after TBI
lead to the sea instead of land. Most of the infrastructure on the island is and prevents the formation of a permanent scar in the brain [7].
lost and the people are stranded with no means of communication. The
If this approach is successful, a victim suffering from TBI can get an
site of brain injury and the surviving cells of a TBI victim suffer a similar injection of SAPNS soon after injury at the locus of brain damage. After
dilemma.
the injection, nanofibers would spontaneously create the equivalent
of scaffolding onto which glia, “support cells,” can migrate and build the foundation for a
permanent bridge. Once bridges are re-created, the scaffolding would disappear, leaving newly
formed channels of communication. SAPNS helps surviving neurons get through to the area
with damaged tissue and form new connections that adapt to the new microenvironment in
the damaged region of the brain. As the surviving brain cells begin to regrow, paralyzed body
parts can regain their functionality [8].
SAPNS is not the only nanomedicine that helps in the treatment of lesions; however, it is by
far the best to date. The novel biomaterial has five helpful amalgamated properties that are not
found in other types of nanomedicine. First, SAPNS has a minimal risk of carrying a biological
contaminant present in animal-derived biomaterials, due to its composition of naturally
occurring amino acids. Furthermore, SAPNS provides a true three-dimensional structure in
which the neurons can grow and migrate to fill the lesion. The use of SAPNS is safe because the
body has no autoimmune or tissue inflammatory response to the newly introduced substance.
The biomaterial also has immediate hemostatic properties that prevent internal bleeding in
the brain. Lastly, an important feature is that SAPNS can be injected into the brain in a liquid
form. This makes it compatible with any shaped lesion cavity, whereas most other biomaterials
used to repair the central nervous system are either solids or gelatins. Using older biomaterials
makes getting the appropriate size and shape problematic, and as a result increases the risk of
secondary injuries during transplantation due to improper shape [7].
Although notoriously known to be irreparable after sustaining damage, brain cells can
actually regenerate to a limited extent [9]. Drs. Guo and Leung (2009) together with their
colleagues capitalized on this ability using SAPNS to promote growth shortly after the trauma
(figure 1D). To test the effectiveness of SAPNS on TBI, the researchers created similar lesions
in two groups of adult laboratory rats and then treated one group with SAPNS and the other
with a standard saline solution (control group). Comparing the brains after several weeks
of rehabilitation, the researchers reported “saline treatment in the control animals resulted
in a large cavity in the injured brain, whereas no cavity of any significant size was found in
the SAPNS-treated animals.” They quantified how well SAPNS treated the injury by looking
for macrophages, a type of white blood cell. By counting the number of macrophages, the
researchers, in essence, obtained an estimate of how extensive the neuronal injury due to TBI
was. Macrophages can be thought of as cells that “bury the dead.” When Guo and Leung
found fewer amounts of macrophages at the damage site in the SAPNS- versus saline-treated
rats, they concluded that there were fewer dead cells to “bury” in the SAPNS-treated brains.
The nearly complete recovery (figure 1E) showed that the new nanobiomaterial promoted
quick healing of brain tissue after TBI [7]. One highly favorable solution is to combine this
technology with stem cell therapy, which has potential for providing a complete recovery [6].
By creating a permissive environment for neurons to migrate across and form new adaptive
connections, SAPNS shows great promise in eliminating the number one cause of death in
people under the age of 45 [10]. The finding may be as great a triumph as landing on the Moon.
Enabling re-creation of just a piece of the most complex matter in the universe translates into a
small step forward for the TBI patient, but a giant leap for mankind.
REFERENCES
[1] Centers for Disease Control and Prevention (CDC). (2010). How many people have TBI?. Retrieved from http://
www.cdc.gov/traumaticbraininjury/statistics.html.
[2] Morris, R. & Fillenz, M. (2003). Neuroscience: Science of the brain. The British Neuroscience Association.
[3] Society for Neuroscience. (2008). Brain facts: A primer on the brain and nervous system.
[4] Rockswold, G. (2012). Traumatic brain injury. The Minneapolis Medical Research Foundation. Retrieved from
http://www.mmrf.org/research/tbi.html
[5] Cho, Y. & Borgens, R. B. (2011). Polymer and nano-technology applications for repair and reconstruction of the
central nervous system. Experimental Neurology, 233, 126-44.
[6] Brodhun, M., Bauer, R., & Patt. S. (2004). Potential stem cell therapy and application in neurotrauma. Experimental
and Toxicologic Pathology, 56, 103-12.
[7] Guo, J., Leung, K. K. G., Su, H., Yuan, Q., Wang, L., Chu, T.-H., Zhang, W., Pu, J. K. S., Ng, G. K. P. & Wong, W.M. (2009). Selfassembling peptide nanofiber scaffold promotes the reconstruction of acutely injured brain. Nanomedicine:
Nanotechnology, Biology and Medicine, 5, 345-51.
[8] Ellis-Behnke, R. G., Liang, Y.-X., You, S.-W., Tay, D. K. C., Zhang, S., So, K.-F., & Schneider, G. E. (2006). Nano neuro
knitting: peptide nanofiber scaffold for brain repair and axon regeneration with functional return of vision.
PNAS, 103, 5054-59.
[9] Liang, Y.-X., Cheung, S. W. H., Chan K. C. W., Wu, E. X., Tay, D. K. C., & Ellis-Behnke, R. G. (2010). CNS regeneration after
chronic injury using a self-assembled nanomaterial and MEMRI for real-time in vivo monitoring. Nanomedicine:
Nanotechnology, Biology and Medicine, 7, 351-59.
[10] Langlois, J. A., Rutland-Brown, W., & Wald, M. M. (2006). The epidemiology and impact of traumatic brain injury:
a brief overview. Journal of Head Trauma and Rehabilitation, 21, 375-78.
MAXINDER S. KANWAL/GRAPHIC
Figure 1. Schematic representation
of TBI and SAPNS-based treatment.
(A) Neural network showing cell bodies
(filled circles) and their connections.
(B) Primary injury due to traumatic
brain injury (TBI). (C) Secondary injury
around the periphery of the primary
injury. (D) Self-assembling peptide
nanofiber scaffold (SAPNS) injected
at the site of injury. (E) Newly formed
connections (red lines) after injection of
SAPNS.
Advances in
Personalized Medicine
by Collin Dillingham
edited by Mina Askar
reviewed by Dr. Rudolph Kirchmair
On one episode of the hit TV show “House”, Dr. Gregory House diagnoses a patient with Von Hippel–Lindau disease. This uncommon illness
confuses the victim’s senses, but after a few days of paying careful attention, he saves the patient’s life. Sadly, doctors like him do not exist in real
life. However, breakthroughs in the medical field are helping doctors and
researchers to pinpoint specific diseases and administer the appropriate
treatment more accurately than ever before.
Thousands of medical professionals and researchers across the globe
work together to expand our collective knowledge of the human body
and all of its possible ailments, as well as to develop and utilize many new
methods and drugs for curing those in need. Unfortunately, our progress
in the medical field is paralleled by an increasingly diversified scope of
known diseases. With so many new diseases, the hundreds of different
variations of cancer being just one example, medicine must become more
personalized to the individual patient in order to be effective.
Medical research commonly utilizes lab animals, namely mice, to test
new drugs and prepare them before being implemented in humans. A
new form of animal testing has recently made its way into the medical
society, and scientists are calling it “Avatar” testing. No, contrary to popular belief, it does not involve putting patients into the minds of large blue
creatures. The purpose of avatar testing is to take the diseased cells of a
patient and implant them into a mouse. The tumor, or whatever culture is
being observed, is then grown, extracted again, cut up and re-implanted
into multiple mice until many mice are living with the same tumor [1].
Test mice are commonly bred with weak immune systems for two
reasons: to allowdiseases to take hold in them more readily and so that
thetumor implanted into them will cause them to take on a medical state
very similar to their human patient. After the batch of mice with the patient’s specific tumor is ready, researchers are able to test numerous different variations and combinations of drugs and treatments in order to find
the one that might be the most effective in the human patient.
Avatar testing, although it allows doctors to assign prescriptions that
may have been overlooked before, does have its drawbacks. For instance,
the process is lengthy, typically taking two to four months to prepare the
mice and longer for analysis1. On top of the time, something which patients may not have enough of, the process is expensive. For one New
Jersey patient who opted for avatar testing to find a treatment for his lung
cancer, the testing cost over $25,000 [1].
The financial and time concerns are only part of the risk; animal testing has always been executed knowing that certain treatments that work
in animals may not work in humans. The avatar testing process usually
gives doctors a better insight into what may help their patient, but the
results are not always foolproof. If the process is streamlined and made
available to the public, however, it has the potential to open up a whole
new industry within the medical field; entire laboratories and companies could be devoted to growing the avatars custom-fit for every patient,
bringing greater accuracy into the science of diagnostics.
Personalized approaches to modern medicine are not restricted to
drugs and medications; researchers such as Dr. Steven Badylak have been
pioneering the field of muscle regeneration for decades and have devised
a new way to completely regrow damaged muscle tissue utilizing certain
structures found in the organs of pigs [2]. These structures are called “extracellular matrices”, and serve as a roadmap for cell generation within
the bodies of living things. The extracellular matrices look like webs that
outline the tissues of our organs, and researchers have found that their
purpose is to act as a scaffold for cells to grow on, while at the same time
only allowing specific types of cells to grow. In essence, the matrix is a
road map or blueprint for the cells to follow during growth
Seeing the potential in a flexible, cell-growing membrane, Dr. Badylak discovered that by ridding the matrix of all living tissues and adhering it to damaged muscle, the matrices have the capabilities to guide cell
growth and literally rebuild the same muscles that have been damaged
[3]. The procedure has been tested and proven to regrow not just ordinary muscles, but also the complex smooth tissues of internal organs,
such as the linings of our intestines and arteries [2]. For patients, this
means that there is little chance of their bodies rejecting the new tissue
because the majority of the new cells are their own.
MAHIMA AVANTI / GRAPHIC
If ordinary and comparatively simple muscles can be regrown using
these matrices, it is logical to assume that the procedure can be extended
to the more complex organs and systems in our bodies as well. This is
exactly the direction scientists such as Paolo Macchiarini, a doctor at the
Karolinska Institute in Sweden, want to take this field of research. The
process that he and other bioengineers have developed is extremely similar to that of Dr. Badylak, using the same types of scaffolds to encourage
growth, but the procedure required to form a whole organ is a bit more
involved. The most significant difference between the two procedures is
that building an artificial organ requires a scaffold for that organ in particular, yet the purpose of the procedure is to create an organ without
sacrificing any living tissue. In order to circumvent this problem, Macchiarini had an artificial scaffold created out of porous plastic that could
absorb cells and serve the same purpose as an organic one [4]. This plastic
structure, while expensive, can be recreated many times without sacrificing living organs. Once the scaffold is created, it is then laced with a
solution containing stem cells taken from the patient’s bone marrow and
suspended in a nutrient solution. Amazingly, the cells will multiply and
the organ can be fully formed in a matter of just days [4].
While expensive, as such is the case with most experimental procedures, the benefits of having an organ grown practically from scratch and
tailor-made specifically from the patient’s own cells are astronomical;
the months that some patients are forced to wait on waiting lists will be
drastically reduced if and when this process is streamlined enough to be
affordable for the average patient. On top of that, there is little to know
risk of the organ failing due to the body rejecting it.
Using these new technologies, many promising advancements have
been made that will almost surely carry the medical community into a
new era of surgery within the coming decades. Speculative research has
even been done by surgeons such as Dr. Tracy Grikscheit who believe
that the next step of scaffold-based tissue engineering is to actually grow
the organs inside the patient [5]. She believes that, theoretically, a tiny
“seed” scaffold can be placed inside a patient’s abdomen where it can
grow off of the natural blood supply and eventually be extracted and put
in place of the failing organ or tissue. This idea is only in its early stages
of development, though; simple pieces of organs such as intestines have
been grown in mice, but there has been very little testing beyond that5.
With many new research projects under way around the world, doctors and researchers are constantly improving their ability to diagnose
and treat patients based on their specific needs and ailments. Trials and
experimentation may take years and some techniques may not be approved for use in humans any time soon. Nevertheless, more progress is
being made and more lives are being saved.
REFERENCES
[1] Pollack, A. “Seeking Cures, Patients Enlist Mice Stand-Ins”.
[2] Fountain, H. “Human Muscle, Regrown on Animal Scaffolding”.
[3] Chan, B. P., Leong, K.W. “Scaffolding in tissue engineering: general approaches and
tissue-specific considerations”.
[4] Fountain, H. “A First: Organs Tailor-Made with Body’s Own Cells”.
[5] Fountain, H. “One Day, Growing Spare Parts Inside the Body”.
Controlled Release Using an Oral Drug Delivery System
Designed to Improve Treatment of Conditions such as Multiple Sclerosis
BY: Madeline Mouton-Johnston1, Diane C. Forbes2
EDITED BY: Joy Li
ABSTRACT
ORIGINAL RESEARCH
A controlled release drug delivery system suitable for oral administration of a range of desirable therapeutic agents was developed. The drug carrier
was prepared from alginate beads made by adding an alginic acid solution dropwise into a calcium chloride solution. The resulting carrier spheres were
loaded with a model drug and the release behavior was investigated. Such a system could have utility for the treatment of diseases such as multiple
sclerosis that would benefit from improved oral delivery therapeutics.
1. INTRODUCTION:
Multiple sclerosis is one of the most commonly diagnosed
neurological disorders in young adults [1], and it affects approximately
250,000 to 350,000 people in the United States [2]. Multiple sclerosis is
a debilitating disease that primarily damages the myelin around axons
(nerves) and creates irreversible scarring in the central nervous system.
The principal role of myelin is to quickly and efficiently transmit nerve
signals throughout the body. Consequently, the destruction of the
myelin and the damage to the central nervous system obstructs the
transmission of electric signals in the body and can significantly impair
motor functions [1]. The damage to the central nervous system caused
by multiple sclerosis leads to a number of symptoms including fatigue,
memory loss, and gastrointestinal problems, such as bowel problems and
bladder dysfunction [3].
There are treatments available to slow the progression of multiple
sclerosis, but there is no cure [1]. Most available treatments, such as
interferon β-1a (Avonex® or Rebif ®), use subcutaneous or intramuscular
injections [4]. The newest treatment Natalizumab (Tysabri®) requires
intravenous injection [5]. The benefits of the treatments are not without
cost to the patient’s quality of life; the injections are painful and most
patients experience flu-like symptoms and general discomfort for almost
a full day after taking the injection [6]. Dosing frequency typically
ranges from daily to weekly, depending on the drug [7]. Other routes of
administration could alleviate some of the patient discomfort; indeed, an
orally delivered therapeutic would eliminate the pain associated with the
injection [8].
Fingolimod is the first orally administered multiple sclerosis drug
[7]; however, the therapeutic is associated with potentially fatal side
effects, including a decrease in heart rate [9]. As a result, patients must
remain at the doctor’s office for the first six hours following their first
dose. A controlled release system may reduce the side effects immediately
post-administration of fingolimod and eliminate the need for medical
observation for six hours, thus improving the quality of patients’ lives.
2. PURPOSE
The purpose of this study was to investigate the release behavior
associated with the use of alginate beads as carriers in a controlled
delivery system. A significant challenge of oral delivery is preventing the
drug from disintegrating in the stomach so that it can be fully released
into the upper small intestine. The stomach is very acidic and has a
pH around 2 while the upper small intestine has a pH around 7.4. The
development of alginate beads as a drug delivery technique is promising
because the material is insoluble at low pH values, remaining intact to
provide protection to the therapeutic, while dissolving to release the drug
at neutral pH values. The alginate contains anionic sites, which allow the
interaction between the alginate anion and the calcium cation to crosslink
the chain to form a gel network [10] (see Fig. 1). The crosslinks connect
the linear chain to form a well-defined structure. The advantage of using
alginate in an oral delivery system is that alginate is biocompatible and
biodegradable [11].
Fig. 1: Linear alginate chains (a) are joined by divalent calcium cations (b),
and the chains stack to form a regular physical network (c).
3. METHODS
The following products were purchased from Sigma-Aldrich (St.
Louis, MO): alginic acid sodium salt from brown algae, Tartrazine, and
Erioglaucine. The calcium chloride dihydrate was purchased from EMD
Chemicals Inc (Gibbstown, NJ). All water used in the study was ultrapure grade. The microplate reader (Synergy HT) was purchased from
BioTek Instruments Inc. (Winooski, VT).
The synthesis method was adapted from reports in the literature
using calcium chloride crosslinking to form alginate beads [12]. A 2%
w/v solution of alginic acid in distilled water was prepared by combining
0.4 g of alginic acid in 20 ml of water and mixing overnight to dissolve.
A 500 ml sample of 2% w/v calcium chloride solution was then prepared
by dissolving 10 g of calcium chloride in 500 ml of ultra-pure water.
The alginate beads were then created by pushing 5 ml of the alginate
solution through 18G, 20G, and 30G needles with a syringe into the
calcium chloride solution. The purpose of the different sized beads was
to compare release behavior for the different size beads and types of dyes.
The beads were recovered by filtration. Typical beads can be seen in Fig.
2. A 10 mg/ml solution of dye (Eriogluacine or Tartrazine) was prepared
and 20 beads of each sized bead were added with 5 ml dye solution to
soak for 3 days. During this time, the beads where loaded with the dye,
which serves as the model drug.
Tartrazine and Erioglaucine were selected as two model agents to
aid in studying the possible behavior of Fingolimod due to their water
solubility and similar molecular weights.
Tartrazine is an azo dye
primarily used in food coloring. It has a molecular weight of 534.3 g/mol
and is used in various lemon-flavored products. Erioglaucine is also a
colorant with a molecular weight of 792.85 g/mol. Both compounds are
water soluble as is Fingolimod which has a molecular weight of 307.5 g/
mol.
Fig. 2: Alginate beads following synthesis,
prior to loading with dye. Left to right:
18G, 20G, and 30G needles used to make
beads.
1. St. Stephen’s Episcopal High School, Austin, TX
2. Dept. of Chemical Engineering, University of Texas at Austin
Immediately prior to the release study, the particles were recovered
with filtration (see Fig. 3) and rinsed with approximately 500 ml of ultrapure water, until the rinse water was colorless, to eliminate extra dye on
the outside of the particles. Each of the 6 sets of particles (2 colors with
3 sizes each) was then placed into 150 ml of ultra-pure water and stirred.
200 µl samples were taken at designated times of 1, 2, 3, 5, 7, 10, 15, 20,
25, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 minutes.
Fig. 3: Alginate beads following loading with
dye, prior to rinsing. The yellow dye (on the left)
is Tartrazine and the blue dye (on the right) is
Erioglaucine.
4. RESULTS AND DISCUSSION
The alginate microspheres prepared by this method were uniform,
spherical and of substantially good quality. The alginate beads could be
contained in a gelatin capsule that would dissolve in the stomach in order
to aid in oral administration for patients. To investigate the release of the
model compounds from the alginate spheres, we obtained the spectra of
these compounds. The spectra (see Fig. 4) display the absorbance over a
range of wavelengths. Using the wavelength at maximum absorbance to
calculate the concentration enables the most accurate determination at
low concentrations.
Dye
Fig. 5: Calibration curve to calculate
the concentration as a function of
absorbance.
Calibration curves were used to relate the concentration to the absorbance
of the dye with a linear equation in slope/intercept form. The slope/
intercept equation could be found by adding a linear trendline to the data
on the graph as shown in Fig. 5 for Erioglaucine and Tartrazine; the slope
and intercept values are shown in Table 1. The absorbance values on the
calibration curve are found by scanning different dilutions of the dye at
the wavelength of maximum absorbance determined from the spectrum
graph. Absorbance values greater than 2 cannot be measured accurately,
so the most accurate determination of concentration requires dilutions
Intercept
Tartrazine
0.0381
-0.0014
Erioglaucine
0.0139
-0.0017
Table 1: Slope and intercepts of
calibration curves calculated using linear regression. Slope and
intercept have units of mg/ml
and the absorbance is unitless.
Both calibration curves show increased absorbance with increased
concentration. This result is predicted by Beer’s Law (see Eqn. 1), which
states that the concentration and the absorbance of a solution are directly
proportional to each other [13, 14].
A = ε l c
Eqn.1: Beer’s Law
Where A is absorbance, ε is absorptivity, l is length, and c is concentration.
For concentration units of g/ml, the absorptivity ε has units of cm2/g, the
length l has units of cm, and the absorbance A is unitless.
The release study graphs (Fig. 6 and Fig. 7) show the dye concentration
over the duration of the experiment. The concentration was found by
using the slope/intercept equation from the calibration curves of the dyes.
The results from the release studies indicate that the concentration of the
solution increases over a period of time until a certain point when the
concentration level plateaus. The plateau is associated with the maximum
release of dye (model drug) by the carrier. The plateau is achieved after
approximately an hour, with most of the release in the first 45 minutes.
The 18G beads have the highest final concentration of all of the bead
sizes.
Fig. 6: Concentration of Tartrazine
yellow dye in the release solution
following release from the alginate
beads.
Fig. 4: Spectra for Tartrazine and Erioglaucine, yellow and blue dyes,
respectively. Data is normalized (scaled to a maximum of 1) using the
maximum absorbance.
Slope
Fig. 7: Concentration of Erioglaucine blue dye in the release solution
following release from the alginate
beads.
The initial release rate is estimated from the slope of the plot of
concentration versus time at early times as shown in Table 2. The initial
rate of release for each dye is comparable for all the bead sizes. However,
the larger beads released more dye. The bigger beads have the advantage
of holding more dye per bead, but the smaller beads have the advantage
that they can be more easily packaged in a gelatin capsule for oral
administration.
18G
20G
30G
Tartrazine
1.33 x 10-4
1.48 x 10-5
1.17 x 10-4
Erioglaucine
1.57 x 10-4
1.57 x 10-4
6.57 x 10-5
Table 2: Initial release rate of dye estimated from slope of concentration
versus time for the first 20 minutes, reported in units of mg/(ml min).
ORIGINAL RESEARCH
The wavelength of maximum absorbance was determined by scanning
a sample of dissolved dye across the full range of wavelengths for visible
light. A plate reader (Synergy HT, BioTek Instruments Inc.) was used to
measure the absorbency values; the Erioglaucine samples were scanned
at 630 nm and the Tartrazine samples were scanned at 410 nm.
Dilutions of each dye were prepared to make a calibration curve. The
10 mg/ml dye was diluted 1:10 to make a 1 mg/ml solution. Another 1:10
dilution was then made to create a 0.1 mg/ml solution. The 0.1 mg/ml
dilution of each dye was used to prepare dilutions of 0.1, 0.05, 0.04, 0.03,
0.025, 0.02, 0.015, 0.01, and 0.005 mg/ml.
that will have absorbance values less than 2.
5. CONCLUSIONS:
This study demonstrates that alginate beads may be an effective controlled
release drug delivery system suitable for oral administration. Our
alginate beads release dye over 45 minutes and would provide a more
delayed release than dye (or drug) alone. The size of the beads had a more
significant impact on the total dye loaded than on the initial release rate.
For future studies, it would be valuable to look at the effect of rinsing and
storage on the release kinetics of the alginate beads as well as the effect of
changing pH conditions.
ORIGINAL RESEARCH
Acknowledgements:
This work was performed in the Graduate Research in High School Hands
(GRiH2) Program of the Laboratory of Biomaterials, Drug Delivery and
Bionanotechnology of the Departments of Chemical and Biomedical
Engineering of the University of Texas at Austin. This program was
established in June 2011 by Cody Schoener and William Liechty. Special
thanks are expressed to Prof. Nicholas A. Peppas for providing laboratory
space, materials, and equipment. This research was supported in part by
a grant from the National Science Foundation (CBET-1033746). D.C.F
acknowledges support from the National Science Foundation Graduate
Research Fellowship Program (DGE-1110007).
REFERENCES:
[1] “What is Multiple Sclerosis?”. http://www.msassociation.org/about%5Fmultiple% 5Fsclerosis/whatisms/ (2012).
[2] “Multiple Sclerosis: Hope Through Research”. http://www.ninds.nih.gov/disorders/ multiple_sclerosis/detail_multiple_sclerosis.htm#203893215 (2012).
[3] “What are the Symptoms of MS?”. http://www.msassociation.org/ about%5Fmultiple%5Fsclerosis/symptoms/ (2012).
[4] “Interferon beta-1a Subcutaneous Injection”. http://www.ncbi.nlm.nih.gov/ pubmedhealth/PMH0000249/ (2012).
[5] “Natalizumab Injection”. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000289/ (2012).
[6] “MS Injections”. www.msactivesource.com/ms-injections.xml (2012).
[7] “Treatments for Multiple Sclerosis (MS)”. http://www.msassociation.org/ about%5Fmultiple%5Fsclerosis/treating/ (2012).
[8] N. Kamei, M. Morishita, H. Chiba, N.J. Kavimandan, N.A. Peppas, and K. Takayama, “Complexation Hydrogels for Intestinal Delivery of Interferon beta and Calcitonin”, J. Controlled
Release, 134, 98-102 (2009).
[9] “Fingolimod”. http://www.nationalmssociety.org/about-multiple-sclerosis/what-we-know-about-ms/treatments/medications/fingolimod/index.aspx (2012).
[10] A. Augst, H. Kong, and D. Mooney, “Alginate hydrogels as biomaterials.” Macromol. Biosci., 6, 623-633 (2006).
[11] H. Tønnesen, and J. Karlsen, “Alginate in drug delivery systems.” Drug. Dev. Ind. Pharm., 28, 621-630 (2002).
[12] S. R. Marek, W. L. Liechty, and J. W. Tunnell. “Controlled Drug Delivery from Alginate Spheres in Design-Based Learning Course.” 2012 ASEE Annual Conference, 11 June 2012.
[13] Potts, G.E. “Beer’s Law”. http://spinner.cofc.edu/genchemlab/ beers.htm?referrer=webcluster& (2001).
[14] Blauch, D. N. “Spectrophotometry: Beer’s Law”. http://www.chm.davidson.edu/vce/ spectrophotometry/beerslaw.html (2009).
Imagining NUMBERS and SPACE
By: Annie Xu Edited By: An Nguyen
Reviewed By: Dr. Jon Lindstrom
The World of Number-form and Spatial-sequence Synesthesia
“The [picture] never seems on the flat but in a thick, dark grey atmosphere deepening in certain parts, especially where 1 emerges, and about
20.”
“The track is organized around the academic year. The short ends
are the summer and Christmas holidays – the summer holiday is slightly
longer.”
“The figures are about a quarter of an inch in length, and in ordinary
type. They are black on a white ground… the picture is invariable.” [1]
W
ithout context, these might seem like descriptions of printed
images, but they are all products of the mind. They are experiences of
number-form synesthetes, people who involuntarily visualize a map
of numerals in precise locations in space when thinking about numbers, and spatial-sequence synesthetes, people who perceive any sort
of sequence, such as numbers or letters, in visual sequences similar to
number forms.
Synesthesia is a general term describing the condition in which
stimulation of a sense or idea triggers stimulation in another part of the
brain. Resulting experiences include seeing colors when hearing certain
sounds (sound-color), perceiving numbers or letters as having colors
(grapheme-color), experiencing a taste upon hearing particular words
(lexical-gustatory), and imagining letters, numbers, months, or days of
the week as having personalities (ordinal linguistic personification) [2].
The perceptions of synesthetes are distinctive for each individual and
usually remain constant throughout one’s lifetime. These experiences
seem so intrinsic that many synesthetes go through life unaware that
they have a unique condition. As a result, the prevalence of synesthesia
often remains unclear; estimates have ranged from 1 in 25,000 to 1 in
20, though a widely accepted statistic is 1 in 2,000 [2]. It has also been
estimated that females are about 6 times more likely to have synesthesia than males, and researchers have suggested that synesthesia is
more common than previously thought, with connections between
time, numbers, and space being the more prevalent forms.The relation
between perceptions of numbers and space was first documented in the
1880s by English scientist, Sir Francis Galton in his articles “Visualized Numerals” and “The Visions of Sane Persons.” While many people
visualize numbers in a one-dimensional mental number line, with
zero or negative infinity at one end and infinity at the other, numberform synesthetes see the number “line” with twists and curves, usually
unrestricted to a single plane, with each number included occupying a
definite position [1]. Another distinguishing characteristic of numberform synesthesia is that synesthetes do not merely imagine a mental
arrangement of numbers; the mention or thought of a number induces
a vision of the number form, so that the individual actually sees his
number form in the space before him.
Spatial-sequence synesthesia involves the mental placement
of items in a sequence, including numbers, letters, days of the week,
months, and years, in explicit locations in space. A closely related form
of this condition, time-space synesthesia, occurs when individuals perceive units of time as relative to their own body. For example, a patient
with time-space synesthesia has described her perception of the months
as a large 7-shaped figure extending around her waist about a meter
from her body [8]. Depending on what time of day or year a time-space
synesthete is thinking about, his or her viewpoint of the “mental calendar” will often shift, giving a particular direction or area represented by
the past, present, and future [4]. A synesthete describes her visualization
of the months as an “oval with myself at the very bottom, Christmas day
to be precise… As I move through the year, I am very aware of my place
on the oval at the current time, and the direction I am moving in” [8].
These links between cognition of time, space, and vision are sometimes
even connected to other sensory qualities, such as color or texture,
creating a seemingly surreal multi-sensory synesthetic experience.
A variety of theories exist which seek to explain the neuroscience
behind synesthesia. One theory claims that a synesthetic brain contains
no anatomical differences from a non-synesthetic one, and that a functional difference is responsible for the mingling of senses. The theory
proposed that the inhibition of signals to an area of the brain which
processes information from multiple senses is impaired in synesthetes,
so that a neural signal may activate two senses together [2].
However, a second and more widely accepted theory holds that
synesthesia arises from abnormal connections between sensory regions
of the cerebral cortex, so that stimulation in one area will also cause
stimulation in another [5]. The regions of the brain that share a connected activation are usually close in proximity. In the case of numberform and spatial-sequence synesthesia, the cross-activation is thought
to occur between the parietal lobe, which is responsible for numerical
cognition, and the angular gyrus, which controls spatial cognition [6].
RHEA BAE/GRAPHIC
Synesthesia is a mental condition that causes different senses and cognitive processes to be connected.
An example of how a synesthete might perceive the months of the
year in colors and spatial arrangements.
Source: BBC [4], based on an illustration by Carol Steen
Fig. 1-4 (L-R): Number-form synesthetes see a specific arrangement of numerals when thinking about numbers. These arrangements sometimes include
other visual or sensory details, as approximated in these representations of number forms. Sir Francis Galton was one of the first scientists to document
this phenomenon. [2]
Other researchers have proposed that these types of synesthesia arise
from the proximity of regions in the temporal (instead of the parietal)
lobe, which plays roles in sequence coding and the representation of
visual objects [7]. It has been suggested that all humans are born with
these unusual links in the brain, but that the links are usually pruned
away during infancy. A single gene mutation in the X-chromosome
prevents such pruning from occurring and is thought to be responsible
for causing synesthesia [2].
These distinctions in the brains of synesthetes seem to have no effect
on other areas of cognition or perception. There are, however, advantages and disadvantages to the mixing of cognition associated with
spatial-sequence and number-form synesthesia. Research has suggested
a link between spatial-sequence synesthesia and a heightened ability to
form memories dealing with dates and time, and that a strong association exists between spatial-sequence synesthesia and hyperthymesia,
a condition in which an individual can successfully recall events and
times in his own life with extraordinary clarity [8].
People with time-space synesthesia are generally considered to be
more adept at remembering the dates of historical events and often plan
events in their own lives using their visualized “calendar”. There has also
been speculation about a possible connection between number forms
and superior abilities to calculate found in individuals with autistic
savant syndrome. Daniel Tammet, a savant who holds the European
MANY SYNESTHETES EXPERIENCE
FRUSTRATION WHEN DEALING WITH
PROBLEMS THAT DON’T MATCH THEIR
VISUALIZATION OF NUMBERS
record for reciting the most digits of pi and can mentally conduct
enormous mathematical operations in mere seconds, describes his
calculations as arising from the visualization of numbers in his head [3].
Although this mental visualization isn’t exactly number-form synesthesia, it indicates significant implications for the use of synesthetic
perceptions as mnemonic devices and mathematical aids. Despite these
apparent mental advantages, however, some people with the condition
feel an impaired ability to think clearly. Many synesthetes experience
frustration when dealing with problems that don’t match their visualizations of numbers. Hyperthymesia causes excessive details about one’s
life to constantly flood one’s mind, and the visions of numerals associated with these types of synesthesia can be equally distracting. Nevertheless, the world of synesthesia provides a promising field
of study in the brain and the mind. Among the studies at the forefront
of research about number-form and spatial-sequence synesthesia are
those comparing the effects of these mental experiences to those of nonsynesthetes. For example, a simple demonstration of the connection
between numbers and space in the human mind is the spatial-numeral
association of response codes (SNARC) effect [7]. Numerous studies
have shown that when subjects are asked to classify numbers as even or
odd using a button, the responses to larger numbers are quicker when
using the right hand, whereas responses to smaller numbers are quicker
when they are made on the left. This association of numbers and space
is actually reversed for some groups of people such as Palestinians, who
use writing and number systems that run from right to left. Similarly,
when number-form and spatial-sequence synesthetes are given a task
involving numbers or sequences, they respond faster when the numbers
are presented in a manner corresponding to their visualization [8]. It
is unclear what these findings may indicate for more advanced tasks
such as calculations, but the experiences of synesthetes are undoubtedly
deeply rooted in the basic way they comprehend numbers and space. As
a result, further study on these correlations may provide valuable insight
into the fundamental workings of human cognition and perception. It
is unquestionable that aside from providing synesthetes with a unique
and intriguing relationship with abstract concepts, number forms and
spatial perceptions make up an informative and captivating world with
much in store for scientists to uncover.
REFERENCES
[1] Galton, F. Visualised Numerals. J. Anthropol. Inst. 10, 85-102 (1880).
[2] Jensen, A. Synesthesia. Lethbridge Undergraduate Research Journal 2,
http://www.lurj.org/article.php/vol2n1/synesthesia.xml (2007).
[3] Kuchment, O. “A Mind That Touches the Past”. http://news.sciencemag.org/
sciencenow/2009/12/14-02.html (2009).
[4] Gill, V. “Can you see time?” http://news.bbc.co.uk/2/hi/8248589.stm (2009).
[5] “The Neuropsychology of Synaesthesia”. http://scienceblogs.com/neurophilosophy/2007/09/04/the-neuropsychology-of-synaest/ (2007)
[6] Hubbard, E. M., Piazza, M., Pinel, P. & Dehaene, S. Interactions between
number and space in parietal cortex. Nat. Rev. Neurosci. 6, 435-448
(2005).
[7] Eagleman, D. M. The objectification of overlearned sequences: a new view
of spatial sequence synesthesia. Cortex 45, http://www.ncbi.nlm.nih.
gov/pubmed/19665114 (2009).
[8] “The Cognitive Benefits of Time-Space Synaesthesia”. http://scienceblogs.
com/neurophilosophy/2009/11/19/the-cognitive-benefits-of-timespace-synaesthesia (2009).
The Mathematics of Drafting
By Fabian Boemer
Breathtaking speed, utter exhaustion, a final exertion, the last
kilometer of a cycling race is a thrilling prospect. Dozens of riders in
contention for the victory seemingly give up, slow down, and coast to
the finish. Dozens others, meanwhile, drastically accelerate to finish
within tenths of a second from each other. Reaching speeds up to 67
kilometers per hour or 42 miles per hour, the riders are held back, quite
literally, only by air resistance. The ultimate winner must time his or her
final sprint to perfection, making use of a common technique, drafting.
Drafting, also known as slipstreaming, is employed in high-velocity
sports such as car racing, bicycle racing, speedskating, and lowervelocity sports which include swimming and running. The concept
of drafting is for groups of moving objects, in this case, competitors
in sports, to reduce the overall effect of drag, which is the air or fluid
resistance forces acting to reduce the velocity of an object. Drafting
is essential in sports to reduce the average energy expenditure of
the objects, whether they be a running pack or a cycling paceline.
While any competitive athlete will espouse the benefits
of drafting, to understand the scientific basis, we must first
understand drag. Drag force is given by the drag equation:
where FD is the force of drag, is the density of the fluid, v is the
velocity of the object relative to the fluid, Cd is the drag coefficient,
and A is the reference area [2]. Inserting values for , v, and Cd, it is
possible to solve for the drag force experienced by any object. We will
consider the drag of a world-class cyclist, a racecar driver, and a runner.
First in our analyses is the 2012 Tour de France winner, Bradley
Wiggins, who covered the 3496.9 km course in 87 hours, 34 minutes, and
47 seconds, at an average of 39.9 kilometers per hour. [3]. Air, the fluid
cyclists travel through, has a density of approximately 1.225 kg/m3 [4].
Finally, a racing bike, with crouched rider and tight clothing, has a drag
coefficient of 0.52, with a frontal area of 0.55 m2 [5]. Inserting these values
into the drag equation, we calculate the drag force to equal 280 Newtons.
Next, we consider the 2012 Daytona 500 winner, Matt Kenseth,
who covered the 200 lap course at an average velocity of 140.256
miles per hour or 224.41 kilometers per hour [6]. Kenseth’s car, a
Ford Fusion, has a drag coefficient of 0.33 [7], and high-end race
cars have frontal areas of about 1.8 m2 [8]. Again, air has a density of
1.225 kg/m3. These values result in a drag force of 15,000 Newtons.
Lastly, we focus on 2012 Olympic 1500m winner, Taoufik Makhlaoufi,
who covered the distance in 3 minutes and 34.08 seconds, at an average
speed of 25.22 kilometers per hour [9]. The drag coefficient of a runner is
approximately 0.9, and a frontal area of 0.478 m2 [10]. Air, still, has a density
of 1.225 kg/m3. The drag equation yields a drag force of 170 Newtons.
The optimal runner, rider, or driver, will orient him- or herself to
minimize the air resistance force. Air resistance reduction in drafting
Edited by Kenneth Xu
riders has been measured at 44%, in drafting runners at 89% [11], and
in racing vehicles at 25% [12]. A 44% air resistance reduction will reduce
the force Bradley Wiggins exerts against air by 130 Newtons. Likewise,an
89% air resistance reduction will reduce the force Taoufik Makhlaoufi
exerts against air by 150 Newtons. A 25% reduction in air resistance
will result in a 3750 Newton air resistance reduction for Matt Kenseth.
Now we consider the effects of these forces in each competitor’s
respective race. Bradley Wiggins, on bike, can be estimated to
weigh 80 kilograms or about 175 pounds. By Newton’s Second Law,
Wiggins’ acceleration by reduced air resistance will be 1.54 m/
s2. If Wiggins were able to draft optimally for half of his race one
second at a time, the additional distance he covers is given by:
where we set initial velocity to 0. Inserting a = 1.54m/s2, each
one-second drafting period gains .768 meters. Over the course
of a 3,158,287 second race, we find Wiggins would travel
1,212 kilometers further, an entire 35% of the race course.
Matt Kenseth’s car weights at least 3400 pounds, 7480 kilograms,
by NASCAR requirements. A 3750 Newton force will accelerate
7480 kilograms at 0.5 m/s2. Assuming, again, Kenseth drafts one
second at a time for half the race duration of 3.56 hours, we find
Kenseth would travel 1600 meters further, .2% of the race distance.
Finally, Taoufik Makhlaoufi, an average 70kg runner,
will accelerate at 2.13 m/s2. One-second drafts over half the
race duration of 214.08 seconds, would result in Makhlaoufi
traveling 114 meters further, a full 7% of the race distance.
Thus, our rough calculations find initially large benefits to drafting
in running and cycling. While drafting in automotive racing is found
to be less effective than in other sports, actual race practices suggest
automotive drafting is among the most important race strategies.
Likewise, though drafting has been downplayed in running, it shows
significant potential in our preliminary glance. Nevertheless, even
considering the rough assumptions, we have been able to apply
mathematical definitions and physics equations to a commonplace
sports phenomena. In certainty, the underlying physical principles are
intriguing past the point of enduring hours of running, cycling, or driving.
The principles of drafting, aerodynamics, and air resistance have
immeasurable potential to the fields of aircraft, automobiles, renewable
energy, and sailing. Successfully understanding and applying these
principles can improve gasoline mileage, generate wind power, and ensure
structures are able to cope with wind loads. Heating, ventilation, piping,
and urban pollution are just some extensions of fluid dynamics along with
one of the most popular diversions: sports. Indeed, the final thrilling sprint
finish employs the concepts of air flow to entertain billions worldwide.
REFERENCES
[1] “2012 Tour De France.” 2012 Tour De France. Training Peaks, 2012. Web. 18 Jan. 2013.
[2] Benson, Tom. “The Drag Equation.” The Drag Equation. NASA, 10 Aug. 2010. Web. 18 Apr. 2013. <http://www.grc.nasa.gov/WWW/k-12/airplane/drageq.html>.
[3] Westemeyer, Susan. “Tour De France 2012.” RSS. Cycling News, 22 July 2012. Web. 18 Jan. 2013. <http://www.cyclingnews.com/races/tour-de-france-2012
stage-20/results>.
[4] “Density of some common gases.” http://www.avlandesign.com/density_gas.htm
[5] Kulju, S. “Aerodynamics of Cycling. “ www.enterprise.mtu.edu/velovations/aerodynamics.ppt
[6] “Daytona 500.” Daytona 500. NASCAR, 2012. Web. 18 Jan. 2013. <http://www.nascar.com/races/cup/2012/1/data/results_official.html%20>.
[7] “Automobile Drag Coefficient.” Wikipedia. Wikimedia Foundation, 17 Apr. 2012. Web. 18 Jan. 2013. <http://en.wikipedia.org/wiki/Automobile_drag_
coefficient>.
[8] “Ford.” http://www.mayfco.com/ford.htm (2004).
[9] Fazackerley, Karen. “Taoufik Makhloufi Wins Men’s 1500m Gold for Algeria.” BBC News. BBC, 7 Aug. 2012. Web. 18 Jan. 2013. <http://www.bbc.co.uk/sport/0/
olympics/18903628>.
[10] Pugh, L. “The Influence of Wind Resistance in Running,” jp.physoc.org/content/213/2/255.full.pdf (1970).
[11] Olds, T. “The mathematics of breaking away and chasing in cycling” <danpat.net/docs/brekaway.pdf>.
[12] Browand, F. “Reducing Aerodynamic Drag and Fuel Consumption.” Global Climate and Energy Project (2011).
High Speed Rail
The Future of
American Transportation
by Eric Chen
edited by Frank Pan
Whether by foot, by boat, or by horse, humans have always pursued
ways to get around and about. Because humans are social creatures, the
ability to go around to different places is an integral part of daily life.
With different forms of transportation come trade, economic growth,
and the sharing of ideas. In 1804, the invention of the steam train proved
the human intellect’s ability to innovate and design new methods for ageold necessities1. Recently, a new transportation method has been developed that has the potential to completely change the future of American
transportation, again.
High Speed Rail (HSR) is a type of passenger transport that operates at extremely high speeds, as indicated by its name. HSR refers to a
complex system of modern rail technologies that allows trains to reach
higher velocities than standard commercial trains can. These technologies include advanced signaling techniques, dedicated railways, and innovative maintenance, all of which contribute to the overall effectiveness
of the system. The minimum speed limit to qualify as HSR was set by
the European Union, which “ofﬁcially adopted Directive 96/48, which
deﬁnes high-speed rail as trains capable of reaching speeds of 155 mph
on dedicated, high-speed tracks or 125 mph on conventional tracks”2.
The maximum speed recorded was in Shanghai, with trains reaching an
official top speed of 260 mph. This technology is currently being used in
countries such as France, China, and Japan, but as of now, it has not yet
reached the United States. With so many countries using the opportunity
to develop hi-tech transportation systems, it is important to consider, if
the US desires to keep up with the pace. This
appealing technology has many benefits, but
it also has potential consequences that leave
many uncertain as to whether or not this
would actually be good for the US.
Many advocates for HSR posit that the
development of the system is essential to
jumpstart the current stagnant and fragile
economy. Analysts assert that the American economy is shifting to what is called a
post-industrial knowledge economy, or an
economy based on the creativity and innovative capabilities instead of manual factory
labor3. However, the government has not
been doing enough to follow this economic
trend. Richard Florida, professor at George
Mason University, states that the economy
is not going to be solved by fiscal or monetary policies, but rather by deep structural
reforms through programs like HSR3.
Implementation of an HSR system
would boost the economy in three main
ways: Direct job creation, expanded tourism, and spatial agglomeration2. The first
benefit is in regards to short-term economic
recovery. The development of HSR would
require people to develop, design, and con24| JOURNYS | SPRING 2013
reviewed by Mr. Andrew Corman
struct—all of whom would be employed through the government. China
employed over 100,000 workers in its construction of a high speed rail
from Beijing to Shanghai2. Another benefit would be the attraction of
tourists and business travelers. Just as airports bring in visitors and their
spending of money, HSR would pull travelers in and benefit the local
economy. A study conducted by the U.S. Conference of Mayors reported
that annual revenue would be increased by $360 million in metropolitan
Los Angeles, $50 million in the Chicago area, and $100 million in Greater
Albany2. The third benefit, spatial agglomeration, is the linking of business locations by shrinking distances. Greater proximity between major
business locations, also called mega-regions, would decrease transit times
and increase productivity. Mega-regions produce 2/3 of the economic
output in the status quo, so linking these regions together in a cheaper
and more efficient way has the potential to increase the economic output
even further4. The HSR system would also drastically reduce US oil usage, because of its primary reliance on electricity. The benefit to less oil
used is that the US also becomes less oil dependent. With less foreign oil
imported, the US would gain greater economic benefit stemming from
independence5.
Another advantage for the United States is that the HSR system would
drastically reduce air pollution. According to the World Health Organization, air pollution causes early death in 70,000 people per year in the
US alone and 3 million worldwide5. The electrically powered HSR is a
clean form of transportation that would help take cars off the road, and
CRYSTAL LI / GRAPHIC
AMY CHEN / GRAPHIC
airplanes from the sky. Although HSR could potentially reduce the automobile and airline industry and thus add on to the unemployed population, the long term economic gains through spatial agglomeration would
outweigh the short-term shocks. With people taking this new transit system, the carbon emission from idle cars in traffic and fuel guzzling planes
in the sky would be reduced by 6.1 billion pounds6. Because of the high
fatality rate, any attempt to reduce air pollution is highly beneficial to the
nation.
As attractive as this transportation system seems, it comes with some
drawbacks. The critics of the HSR system say it will be too expensive and
problematic. Currently, the economy is fragile, and it can be tipped either
way by beneficial or fiscally irresponsible spending. Because of the fragility of the economy, many experts are reluctant to jump into the development of a major infrastructure plan. Walter Mead, Professor of Foreign
Affairs and Humanities at Bard College, states that the HSR system is
too expensive, and will plunge the economy into an even deeper recession7. He claims that the benefits of the plan are not sufficient to justify
the expenses. Considering the current state of the economy, fiscal irresponsibility is not an option. If the economy collapses, the US will lose
its economic and military hegemony. A major cause for concern is that
periods of major economic and hegemonic decline have been empirically
linked to war8. Economic crises cause a redistribution of world power,
and would lead to global uncertainty and miscalculation. Periods of weak
economic performance are also statistically linked to increased use of
force and terrorism. Bad economic times have been empirically paired
with wars, from the American Revolution to the Cold War8. With these
potential impacts in mind, the reluctance of some individuals becomes
quite understandable.
The national development of a high speed rail system has the potential
to either jumpstart the economy or send it into a downward spiral. The
advocates for the plan are extremely enthusiastic, claiming that it is the
solution for air pollution, the economy, and much more. On the other
hand, many are skeptical about the implementation of this plan. But with
the dreaded impacts of economic collapse in mind, their claims also seem
justified. Both sides are extremely well warranted, but no matter what
decision policymakers make has the potential to drastically change the
future of America.
REFERENCES
[1] "When Was The Steam Train Invented?" Blurtit. N.p., n.d. Web. 08 Dec. 2012.
[2] Todorovich, P, Schned, D, & Lane, R High-Speed Rail (2011)
[3] “The Roadmap to a High-Speed Recovery”. (2010)
[4] High-speed rail, the knowledge economy and the next growth wave. Journal of Transport Geography 22, 284-285 (2012)
[5] “Air Pollution Fatalities Now Exceed Traffic Fatalities by 3 to 1.” (2002)
[6] Dutzik, T. Why Intercity Passenger Rail? (2010)
[7] “The American Interest” (2012)
[8] Economic Integration, Economic Signaling and the Problem of Economic
Crises (Emerald Group Publishing, England, 2010)
Applications of
Fourier Series and
Transforms
By Peter Manohar For many years Joseph Fourier had tried to develop a function to
model the distribution of heat in a metal object in order to solve the
heat equation. In 1822, he succeeded and published his research in
his Théorie Analytique de la Chaleur, or Analytic Theory of Heat.
In this book he showed his method for developing a function that
described the distribution of heat throughout a metal plate at any
time. He claimed that any periodic function of a single variable could
be expressed in a series of sines and cosines of that variable, and used
this type of trigonometric series to solve the heat equation. This type
of series that he developed was later named Fourier series in his honor.
A
Fourier
series
of
any
integrable
periodic
function gives a precise representation of the function as an
infinite sum of sines and cosines. The Fourier series of an
integrable periodic function with a period of 2L is defined as
where
and
The substitution replacing nx with πnx/L in the trigonometric
function generalizes the series for functions of any period, not just
periods of 2π. Also, the values of the constants an and bn can be
derived by multiplying both sides of the first equation by cos(mx) or
sin(mx) and integrating from -L to L [1]. For example, the square wave
is a periodic function that has the shape of a square. It is defined as
Edited by Selena Chen
and is periodic on 2L. Simply by looking at the graph of the function
(above), it seems impossible that it could be represented only by using
sines and cosines. However, by evaluating the integrals for the constants
using the function f(x), the values of the constants can be found.
The value of an = 0, while the value of bn = 4/πn when n is odd, or 0
when n is even. Therefore the Fourier series for the function S(x) is
Graphing the Fourier series alongside the original function S(x),
it is clear that the Fourier series is just another way of expressing the
same function. Like other infinite series representations of functions,
Fourier series can also approximate the value of a function using partial
sums. The nth partial sum of a series is the sum of the first n terms of
the series. The Fourier series approximation of a function becomes
more accurate as n increases and more partial sums are taken. The
picture above contains the first five partial sums for the square wave S(x)
[2]. From the picture it is clear that the approximation is much more
accurate at the 5th partial sum (purple) than the first partial sum (red).
Generally, Fourier series are used to model periodic functions
occurring in nature that cannot be expressed as the sum of a finite
number of cosine and sine terms. A Fourier series of a periodic function
is used to find its Fourier transform. Fourier transforms are functions
that have been redefined to be a function of frequency instead of time,
yielding the amplitude of the wave of the function at any frequency.
The graph of a Fourier transform yields the frequency spectrum of a
function, with the amplitude of the waves plotted against the frequency.
The sum of all the waves described by the Fourier transform (from the
frequency and amplitude) is the Fourier series of the original function. Essentially, the Fourier
transform of a wave splits it into the individual waves that make up its Fourier series. Fourier transforms
are typically used to analyze sound and produce the frequency spectrum in spectroscopy.
Fourier transforms are used constantly in sound analysis. The human voice emits many sound waves of different
frequencies when words are spoken. A microphone takes this noise and converts it into an electric signal that is
recorded. However, the recording cannot be analyzed because it is impossible to identify the frequencies of the individual
waves and the intensity of the waves in the sound being emitted. Fourier transforms become especially useful in that they allow
us to interpret the unreadable data into data that can be used. The picture below contains two graphs. The one on the left shows the
raw recording of a sound from a microphone, and the one on the right is its Fourier transform. The Fourier transform makes it easier
to see the many different sound intensities (loudness) and frequencies (pitches) contained within the original recording [3].
In spectroscopy, Fourier transforms are used to decompose a ray of light containing many wavelengths into individual
waves. This can be used to measure the intensity of the waves at a certain frequency without having to measure the intensity of
the entire ray at that particular frequency. In the above diagram, the sound that is being recorded includes all of the frequencies,
and the Fourier transform allows the intensity (amplitude) of each individual wave at a particular frequency to be measured. This
is important because the sound can be broken down into the many waves that it contains, without any extra measurements needed.
Digital sound is also generated using Fourier series and transforms. Speakers generate sound by emitting waves of different
frequencies and amplitudes. In order for the speaker to generate the sound described by the left image, it would create all of the waves
with frequencies and amplitudes described by the Fourier transform in the right image, as the effect created by the many waves will
reproduce the original sound. Essentially, the speaker is emitting all the Fourier series of the original wave to reproduce the sound [4].
Moreover, dubstep music is created using a synthesizer that modifies different types of waves. The synthesizer used by the dubstep artist
generates waves using Fourier series that are then emitted through a speaker. The waves can be modified by variations of synthesis using Fourier
transforms. Three types of synthesis generally used are additive, subtractive, and granular synthesis. Additive synthesis blends together multiple waves
at different frequencies to create a sound. Subtractive synthesis removes different harmonic tones and frequencies from sound prior to its emission from
the speaker. Granular synthesis divides a segment of sound into multiple partitions and rearranges them or removes them. The synthesizer is used to
vary the length of the partitions and the arrangement. This creates either larger or smaller breaks in the sound that listeners often hear in dubstep music.
Other more complex types of synthesis are also used to modify sound and create computerized effects within the music, giving it a digital quality [5].
Fourier series and transforms have a myriad of applications in the world. They play an influential role in numerous fields of
society; common computer applications such as producing sound from a speaker. Even the qualities of dubstep music that make it so
unique, have a basis in Fourier series. Without it, many of the world’s greatest technological advancements may not have been possible.
REFERENCES
[1] Kaplan, W. Advanced Calculus (Addison-Wesley Press, Cambridge, Massachusetts, 1952).
[2] Weisstein, E. W. “Fourier Series--Square Wave.” http://mathworld.wolfram.com/FourierSeriesSquareWave.html (2012).
[3] K, B. “Voice waveform and spectrum.” (2005).
[4] Alm, J., Walker, J., Time-Frequency Analysis of Musical Instruments 44, www.uwec.edu/walkerjs/media/38228%5B1%5D.pdf (2002).
[5] Price, S.”Granular Synthesis.” http://www.soundonsound.com/sos/dec05/articles/granularworkshop.htm (2005).
SPRING
FALL 2013
2012 || JOURNYS
JOURNYS || 27
27
Surgical Applications of a MATLAB Based Electroencephalography
Analysis Program in the Treatment of Various Forms of Epilepsy
by VEDANT SINGH, RUJUTA R. PATIL
under the guidance of ROXANA A. STEFANSCU, R.G. SHIVAKESHAVAN, SACHIN S. TALATHI
edited by RUOCHEN HUANG
ABSTRACT
The central nervous system is prone to a multitude of neurological diseases, with epilepsy being one of the most common neurodegenerative conditions in children and adult populations. Epilepsy is marked by recurrent seizures caused
by overactive neural activity in multiple regions of the brain. Research was conducted in order to develop a Graphics
User Interface (GUI) using the programming language MATLAB that assists in analysis of electroencephalograms.
The application was aimed to assist scientists and surgeons to visualize and analyze the EEG seizure data. In order to
produce such a program, several well-known functions such as fread and uigetfile have been employed. The program
was functional and accomplished its goal. The significance of this research is that it can help doctors in determining
the appropriate surgical treatment for their patients with epilepsy and therefore expedite and improve the status of
those afflicted.
ORIGINAL RESEARCH
INTRODUCTION
The brain, an organ of the central nervous system, is prone to disease. One
of these diseases is epilepsy, an enigmatic and recondite disease. Common neurological signals for epilepsy include recurrent seizures, which
are caused by several factors such as genetics and head trauma. There are
several types of epilepsy, but all of them have a similar neurological process of how the seizures originate. Seizures are caused by synchronized
hyperactive neural activity and can be classified into two categories: focal
and generalized. Focal seizures are marked by uncontrolled neuron firings
that begin in a network on a hemisphere and remain in that hemisphere,
whereas generalized seizures are marked by the neuron firings that originate from one hemisphere and network out into the other hemisphere. [7]
Epileptic seizures are classified as tonic-clonic generalized seizures
or as focal seizures because the neural activity can spread from one
region of the brain to others, thereby changing the classification
of the seizure from focal to generalized. The tonic-clonic generalized seizures are known for their abruptness and begin with the tonic
phase, during which the muscles and the larynx contract, heart rate
increases, blood pressure increases, and pupil dilation occurs. The
tonic-clonic seizures end with the arrival of the clonic phase, during which respiration problems, unresponsiveness, and loss of bowel
control occur. Confusion, headaches, fatigue, and muscle aches ensue.
For focal seizures, the neural activity is concentrated in region of the
brain. [7] Focal epilepsies, which target a region, have a high probability of causing permanent memory loss or extended memory loss if the
targeted region is the temporal lobe. This type of epilepsy is known as
Mesial Temporal Lobe Epilepsy and is the focus of the current laboratory
research. An origin of this epilepsy syndrome can be from head trauma,
because the head trauma can change the normal neural network, thereby
rendering it extremely excitable to epileptogenesis. Epileptogenesis is the
chemical or cellular means by which neurons propagate impulses in an
irregular pattern. The capturing of the neural activity is done by an electroencephalogram, which places 30 electrodes underneath the skull to
detect electrical activity in the cortex. This data is then used to diagnose
the type of seizure, location of initiation of seizure, the episode length,
and the strength of the seizure. It can also be used to predict future seizures by analysis of interictal spikes [7]. The aim of this project was to
create a MATLAB based program that could assist researchers and neurologists analyze electroencephalograms (EEGs). The main challenge was
creating a program that was partially automated so that the user could
input the file by a simple file select feature, analyze EEGs, and save the
time periods during which irregular neural activity occurred into an easily readable text file. In order to address the problem, the program must
be coded through the use of GUIDE, a GUI maker within MATLAB,
with complex callback functions to analyze the input data and to store
the analyzed data, and if this program were to be coded correctly, then
the program would allow for easier viewing and analysis of EEGs. [1,4,7]
METHODS:
In order to assess the hypothesis, research was done to create a program
in the programming language of MATLAB and the GUIDE GUI maker,
which is a part of the MATLAB software. The first component that was
coded was a drop down menu for time options of 30 seconds, 1 minute,
5 minute, 30 minutes, 1 hour, 3 hours, and 7 hours. After coding the time
options in the drop down menu, the update button was coded by connecting the “popupmenu1_sel_index” function to the set function, which
changed the x-axis to the selected time option. A code was then created
by using the xlimits functions to set the time options’ values. After the
time option was selected, the “XLim” was set to the selected time option.
In order to import data into the axes, a menu bar with a drop down “Import Data…” option was created, and the code for selecting the file upon
clicking the “Import Data…” menu selection was the function “uigetfile”,
which selects and stores the name of the file to be opened. The function
“fid” was then set equal to the function “fopen”, which opened the file
previously selected in “uigetfile”. After the pathname and filename were
classified with fid and opened by “fopen”, the code used the accompanying function “fread”, which allowed for evaluation of the selected file,
and set the parameters that enabled the program to read the selected file.
The code also set the “fread” function to a value. The value was subsequently graphed using the function plot. The viewing panel that displays
the graph did not have any coding as there was only one viewing display. Therefore, there were no conflicting displays that the code had to
distinguish between. To code for the scrollbar, the GUI was coded so
that it could view the selected time options and scroll through the time
at one-second intervals. Using the slider button maker from GUIDE,
the slider was created and coded using the switch function and several
case functions. The slider was then coded so that the initial position was
equal to zero and the final position was equal to the value of the time
from the drop down menu options. For example, when the interval at
30 seconds was selected, the final position of the slider would be 30 seconds. The final position was denoted by the function “xmax”, and the
slider’s motion was coded using the “set”, “gca”, “gcbo”, and “get” functions. The “set” function was used to posit the current axes, “gca”, to the
“XLim” defined in the drop down menu, to scroll at the interval of the
previous scrollbar position, “gcbo”, and to calculate the change of position. The function “xincrements” was used to define the increments
between the x-axis values of the time option selected. In the case of 30
seconds, the increments were one second and for 7 hours there were
10-minute increments. Finally, to speed up the GUI experience, the
GUI was coded so that “CTRL-F” emulated the menu option “Import
Data…” and “CTRL-I” launched a popup window that gave instructions.
RESULTS/CONCLUSION
The overall nature of the program improved from a basic presenter
of EEG data, to a more complex and intuitive program that allows for
axes changes and viewing options. Then the drop down menus are
an effective and are functional in changing axes. But the most important aspect of the completion of this coding is the fact that the program does not have glitches in the startup or use, and this is indicative
of the well written and structured coding put into the GUI program.
DISCUSSION
As the results show, the GUI application was coded correctly and functional in viewing EEG signals, but the GUI was not able to analyze the
data as intended. The GUI, as stated in the (problem?, introduction?),
has the capability of assisting scientists and medical professionals in
their respective fields by allowing easy viewing of EEG data. Medically,
the GUI will likely provide an advantage by increasing the rates of success of pre-surgical and postsurgical procedures.
In relation to pre-surgical operations, the GUI may allow the opportunity to meticulously review the recordings before surgical operations are
considered. The common pre-surgical procedures allow for the identification of the functional and structural characteristics of the epileptic focus. Currently, video monitoring of EEGs allows for real time evaluation
of the anatomic location of the epileptic focus, as well as the physical
manifestations of abnormal neural activity. Neuro-electrophysiological
methods that use implanted electrodes to record he neural activity in
combination with neuroimaging techniques, such as MRI scans, have
allowed for structural analysis of the lesions that cause the overactive
activity of certain neural networks involved in the epileptic seizures. The
GUI may enable future EEG data analysis for the pre-surgical operation
of determining the location and severity of lesion. Once these analyses
of pre-surgical EEGs are completed, surgeons can excise the lesion more
accurately. This critical analysis may help surgeons better delimitate the
lesion and thereby providing more effective and precise care.
For post-surgical operations, the GUI may allow for a more accurate
However, the GUI is not the most intuitive and complete program to
analyze EEGs. The GUI is limited by the number of time options currently available; additional time options such as 2 minutes, 3 minutes, 4
minutes, 10 minutes, 15 minutes, 45 minutes, 2 hours, 6 hours, 7 hours,
8 hours, 9 hours 10 hours, and 12 hours may allow for further EEG data
investigations. Also the GUI does not have pause, fast forward, or rewind buttons; if these were to be implemented, then the GUI will allow
for more manual user control and thereby may lead to further critical
analysis of EEG recordings. Also, our GUI application does not have
an automatic feature detection component for isolating the abnormal
neural activity in the EEG signal. Our attempts so far to develop such
a component in the GUI application has not led to reliable results. An
additional limitation is that scrollbar does not allow for the inspection
of EEG data outside of the time interval selected initially. Finally, if this
program were to be combined with other software packages designed to
monitor other aspects of medical importance, such as heart rate, blood
pressure, pulse oximetry, and respiration movements, it could provide
powerful tools to analyze and diagnose various medical conditions. This
suite of medical monitoring may allow for further analysis and more
comprehensive treatment of patients before and after surgery.
In conclusion, this research has provided a strong foundation for
expansion to a more inclusive and intuitive GUI that could be used to
analyze EEG data. Currently, the GUI allows the user to view the EEG
recordings in a simple manner and to analyze them with basic tools
the progression of the EEG over time; however, if the improvements
mentioned previously were to be implemented, the GUI could be more
comprehensive and analytical.
APPENDIX A
Fig.1: Proper opening of GUI
SPRING 2013| JOURNYS | 29
ORIGINAL RESEARCH
As Appendix A shows, the GUI opened and displayed all the components that were coded for. Appendix B shows that the select file component the function “uigetfile” from the code worked. Appendix C
shows that the “fopen”, “fid”, “fread” and “plot” functions all worked
by correctly displaying the graph on the axes in the GUI. In Appendix D, the GUI was functional by displaying all the possible time options. Appendix E displays the GUI’s capability of changing the x-axis
values to the options in the drop down menu while still displaying
the graph created in Appendix C. Finally, Appendix F, shows that
the scrollbar is functionally able to move the graph left and right.
assessment of surgical operations and their efficacy in a long term. Specifically, the most common post-surgical operation is to determine if the
correct excision was made and how effective the excision was in treating
the hyperactive neuron networks. Another possible post-surgical application of the GUI may be assisting in the determination of possible side
effects arising from the surgery.
APPENDIX B
APPENDIX E
Fig.5: Axes change to selected time option
Fig.2: Select File window functional in GUI
ORIGINAL RESEARCH
APPENDIX C
Fig.3: GUI graphs previously selected data in best fit lines
APPENDIX D
Fig.4: GUI displays all possible time options for axes
REFERENCES
[1] Bluemcke, I., Coras, R., Miyata, H., & Ozkara, C. (2012). Defining clinico-neuropathological subtypes of mesial temporal lobe epilepsy with hippocampal sclerosis.
Brain Pathology, 22(3), 402-411. Retrieved from http://dx.doi.org/10.1111/j.17503639.2012.00583.x.
[2] Engman, E., & Malmgren, K. (2012). A longitudinal study of psychological features
in patients before and two years after epilepsy surgery. Epilepsy & Behavior,
24(2), 221-226. Retrieved from http://www.sciencedirect.com/science/article/pii/
S1525505012001771.
[3] Ferrari-Marinho, T., Caboclo, L. O. S. F., Marinho, M. M., Centeno, R. S., Neves, R. S. C.,
Santana, M. T. C. G., . . . Yacubian, E. M. T. (2012). Auras in temporal lobe epilepsy
with hippocampal sclerosis: Relation to seizure focus laterality and post surgical
outcome. Epilepsy & Behavior, 24(1), 120-125. Retrieved from http://www.sciencedirect.com/science/article/pii/S1525505012001308.
[4] Guerreiro, C. A. M. (2012). Surgery for refractory mesial temporal lobe epilepsy: Prognostic factors and early, rather than late, intervention. Arquivos De Neuro-Psiquiatria, 70(5), 315-315. Retrieved from http://www.scielo.br/scielo.php?script=sci_
arttext&pid=S0004-282X2012000500001&lng=en&nrm=iso.
[5] Jardim, A. P., da Costa Neves, R. S., Sales Ferreira Caboclo, L. O., Penteado Lancellotti,
C. L., Marinho, M. M., Centeno, R. S., . . . Targas Yacubian, E. M. (2012). Temporal lobe
epilepsy with mesial temporal sclerosis: Hippocampal neuronal loss as a predictor
of surgical outcome. Arquivos De Neuro-Psiquiatria, 70(5), 319-324. Retrieved from
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0004-282X20120005000
03&lng=en&nrm=iso.
[6] Koorenhof, L., Baxendale, S., Smith, N., & Thompson, P. (2012). Memory rehabilitation and brain training for surgical temporal lobe epilepsy patients: A preliminary
report. Seizure-European Journal of Epilepsy,21(3), 178-182. Retrieved from http://
www.sciencedirect.com/science/article/pii/S1059131111002986.
[7] Lowenstein D.H. (2012). Chapter 369. Seizures and Epilepsy. In D.L. Longo, A.S. Fauci,
D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison’s Principles of
Internal Medicine, 18e. Retrieved from http://www.accessmedicine.com/content.
aspx?aID=9145219.
[8] Polat, M., Gokben, S., Tosun, A., Serdaroglu, G., & Tekgul, H. (2012). Neurocognitive
evaluation in children with occipital lobe epilepsy. Seizure-European Journal of
Epilepsy, 21(4), 241-244. Retrieved from http://www.sciencedirect.com/science/
article/pii/S1059131112000027.
[9] Stretton, J., Winston, G., Sidhu, M., Centeno, M., Vollmar, C., Ili, S. B., . . . Thompson, P. J.
(2012). Neural correlates of working memory in temporal lobe epilepsy - an fMRI
study. NeuroImage, 60(3), 1696-1703. Retrieved from http://www.sciencedirect.
com/science/article/pii/S105381191200153X.
[10] Tsai, M., Hsu, S., Huang, C., Chang, C., & Chuand, Y. (2010, June 19). Transient attenuation of visual evoked potentials during focal status epilepticus in a patient
with occipital lobe epilepsy.. Retrieved from http://www.ncbi.nlm.nih.gov/
pubmed/20714965
Augmented Reality
The Harbinger of the Sixth Sense
By: Anjana Srinivas
I
magine you are on a trip to Paris, intently gazing at the wondrou-s architecture of the Eiffel Tower. Without even taking out
your phone, you frame the structure with a hand gesture to take a
quick photo of the building, and then receive a guided tour of the
attraction on the palm of your hand. Or picture going to a clothing
store, where you find a new shirt that you want to buy. In a frenzied
excitement, you rush to the fitting rooms to try it on, only to find
that all the rooms are occupied. No worries, you immediately take
out your smart phone to scan the shirt, and see a superimposed image of yourself wearing it. Does this sound like a scene from one of
those futuristic science fiction movies? Definitely not; this is reality
— augmented reality!
Augmented reality, or AR, is a technology used to add
information or meaning to real objects and places.AR takes the view
as seen by the user and enhances it with computer generated digital
graphics and imagery. It helps one see beyond what he sees, simulating the possession of a sixth sense. AR technology gives direct or
indirect views of a physical, real-world environment, the elements of
which are augmented by computer-generated sensory inputs. These
sensory inputs, which include sound, video, graphics, or GPS data,
Edited by: Jessica Yu
reviewed by: dr. john Allen
HAIWA WU/GRAPHIC
serve to enhance one’s perception of reality.
AR traces its origin to military applications
introduced in the early nineties through the heads-up display devices
(HUDs) used by jet fighters and helicopters to project night vision
and target information. Later, it was used at the Boeing factory to
assist maintenance engineers by overlaying schematics of the wiring
mesh and maintenance instructions on top of the parts being repaired
[1]. From its modest beginnings, in which only big companies have
been able to afford the technology, AR has broken the wall of unfeasibility and inaccessibility. It has now found its way into consumer
devices that are in daily use.
Consumer devices such as smart phones and tablets contain processors, sensors, and display and input devices that project
data into the user’s field of vision, corresponding with the real object
or space the user is observing. These devices contain elements which
often include cameras and sensors such as accelerometers, GPS,
and solid state compass, making them suitable AR platforms. The
user interface in an AR system is usually speech input or gestures
from the user’s body movements as well as external devices such as a
styluses, pointers, or wands [2].
SPRING 2013| JOURNYS | 31
KALEIGH FLEISCHMANN/GRAPHIC
superimposing graphics and text on realworld objects, as researchers at MIT have
demonstrated through their “sixth sense”
wearable AR device [5]. This application
provides exciting possibilities for AR as it
brings the digital information out of the
confines of an electronic gadget to the
tangible world, allowing interaction with
information using natural hand gestures.
The possibilities of AR are
enormous — from being able to get instant
information on landmarks, to more serious
applications in the medical field. An example of the former would be a tourist pointing his or her camera at the White House
and almost instantly receiving historic and
current information about it. Applications
in the medical field could enable a doctor
to examine a patient and display a patient’s
vital signs like heartbeat, blood pressure,
and medical history on special AR goggles.
AR also has immense potential in revolutionizing teaching methods and making
learning more informative and interactive.
The ability to visualize objects in 3D and
manipulate them in real time is a compelling feature that can deliver sophisticated
teaching applications. Reading a book,
especially for young children, can be made
an immersive experience by augmenting
text with background sights and sounds.
Graphically transporting the reader and
engaging him as a real observer in the
scene would make reading an even more
enjoyable experience for both children and
adults.
Future AR applications will
require increased processing power in
microprocessors that can deliver high performance at low power and cost. Powerful
image recognition and graphics technology
are also at the heart of enabling seamless
and smooth AR applications. Augmented
reality becoming a reality and living up
to its lofty promises are predicated on
the advancements in high-speed wireless
broadband connections that will enable
larger amounts of data to be transferred
with lowest latency.
Since
modern
smart
phones
and
Today’s AR applications use cameras,
Miniaturization of electronic
GPS location services, motion sensors, graphics, tablets are popular today and contain sensors
that are necessary for AR technology, many AR components, cameras, and sensors could
application processors, and high-speed wireless connectivity that are found on most smart applications will use the smart phone or tablet make it possible to embed an entire AR sysscreen as the rendering element. However, the tem into an eye lens. This could perhaps be
phones [4]. Even though several AR-related
the holy grail of AR, heralding the arrival of
future AR rendering system will depend on
applications are available for smart phones
the future man-machine. AR has the potenAR-enabled sunglasses that are lightweight,
today, none of them provide the desired user
tial to change the way we view and interact
comfortable,
and
visually
appealing.
While
AR
experience and, more importantly, don’t pass
with the world around us, forever changing
technology
currently
involves
superimposing
the “wow!” test.
the nature of our interpersonal interactions
graphics and textual content on live images
Therefore, AR is still in its infancy,
and perception of reality.
viewed through cameras on smart phone
waiting for a killer application that will propel
it to the heights that its proponents claim it will screens, future AR application will involve
reach.
REFERENCES:
[1] Obst, Benjamin. “Augmented Reality.” informatik.hu-berlin.de
(2009).
[2] Mullins, Robert. “The Next Smart Phone App: Augmented Reality.”
http://www.examiner.com/article/the-next-smartphone-appaugmented-reality (2011).
[3] Yuen, S., Yaoyuneyong, G. & Johnson, E. Augmented reality: An
overview and five directions for AR in education. Journal of Educational Technology Development and Exchange 4, http://www.
sicet.org/journals/jetde/jetde11/11-10-steve.pdf (2011).
[4] Mistry, P., Maes, P. “SixthSense – A Wearable Gestural Interface.”
http://www.pranavmistry.com/projects/sixthsense/ (2009).
[5] Mistry, P., Maes, P. “Unveiling the Sixth Sense.” http://www.ted.
com/talks/pattie_maes_demos_the_sixth_sense.html (2009).
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CHAPTER PRESIDENTS Anunay Kulshrestha (Delhi Public
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Venkatasubramaniam (Palo Alto), Sharon Liou (Westview),
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STAFF ADVISOR Mr. Brinn Belyea
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Daniel Hyke, Ms. Valeria Draper
SCIENTIST REVIEW BOARD Dr. Aaron Beeler, Dr. Akiva
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Pal, Dr. Erika Holzbaur, Dr. Gang Chen, Dr. Gautam Narayan
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Martin, Dr. Todd Lamitina, Dr. Toshinori Hoshi, Ms. Tracy
McCabe, Ms. Trish Hovey, Dr. Xin Chen
SCIENTIST REVIEW BOARD COORDINATOR Sumana
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CONTRIBUTING AUTHORS Anjana Srinivas, Annie Xu,
Austin Su, Colin Dillingham, Diane Forbes, Eric Chen, Fabian
Boemer, Harshita Nadimpalli, Jessica Yu, Lilia Tang, Maria
Ginzburg, Mattie Mouton-Johnston, Maxinder S. Kanwal,
Nilay Shah, Peter Manohar, Rujuta Patil, Varun Bhave, Vedant
Singh
CONTRIBUTING EDITORS Ahmad Abbasi, An Nguyen,
Emily Sun, Eric Chen, Frank Pan, Ivan Dang, Jenny Li, Jessica
Yu, Jonathan Xia, Joy Li, Kenneth Xu, Kevin Li, Mina Askar,
Ruochen Huang, Selena Chen
DESIGN EDITORS Apoorva Mylavarapu, Christina Baek,
Grace Chen, James Lee, Stephanie Hu
GRAPHICS EDITOR Wenyi (Wendy) Zhang
ASSISTANT GRAPHICS EDITOR Crystal Li
CONTRIBUTING GRAPHIC DESIGNERS Aisiri
Murulidhar, Amy Chen, Angela Wu, Bofan Chen, Carolyn
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Luong, Mahima Avanti, Meejin Choi, Rebecca Wang, Rhea
Bae
2009
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