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April 12, 2005 - Image 5

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The Michigan Daily, 2005-04-12

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news@michig-andaily.com

tbE Aidan Baitl
SCIENCE

5

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MIMICKING OYSTERS

Nobel Laureate speaks
on ultra-cold matter

s Scientists synthesize
By Ankit Sur For the Daily
With ever-increasing demand for more
environmentally friendly technologies,
companies are searching for safer materials
with which to manufacture their products.
University researchers have recently provid-
ed manufacturers with a potential material
from an unlikely source - an oyster.
As more companies demand materials
that are biodegradable and use as few tox-
ins as possible in their production, Chemi-
cal engineering Prof. Nicholas Kotov and
his team have been able to fulfill those
objectives by emulating the process by
which oysters produce pearls.
Kotov said that nacre (pronounced nac-
er), the substance that pearls are made of,
has potential uses in fields such as aero-
space, biomedical and many others.
Nacre is secreted by oysters when irri-
tants get trapped inside their shell. Those
irritants, such as a particles of sand, become
coated - layer by layer - with nacre and
eventually form a pearl.
Kotov said he and his team are at the
forefront of this research effort and have
been able to synthesize nacre in their
lab at the G.G. Brown Building on North
Campus.
The procedure Kotov employs would
produce the same amount of nacre in 67
days as an oyster would produce in one
year by using a simple technique called
layer-by-layer electrostatic assembly.
Layer-by-layer electrostatic assembly
involves taking a charged medium, such
as glass slide used in microscopes, and
immersing it into two chemicals with oppo-
site charges.
The first solution in which the medium is
immersed would be positively charged, and
the second would be a negatively charged
solution. The process continues back and
forth, resulting in an ordered structure built

pearl-like substance for technological use

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GRAPHIC BY GERVIS MENZIES
The process University scientists are using to create artificial nacre.

by the different layers from the oppositely
charged chemicals.
The positively charged solution is
PDDA, a synthetic polymer solution that
has been shown to be biodegradable. The
negatively charged solution is sodium
montmorillonite (clay nanoplatelets),
which is a form of clay. Both substances
are similar to the materials an oyster uses
to create nacre, said Rackham chemical
engineering student Paul Podsiadlo, who
works on the team researching this.
The process of creating the nacre
first begins by taking the glass slide and
immersing it in a pyranha solution, a cor-
rosive mixture of sulfuric acid and hydro-
gen peroxide, which will clean the glass,
Podsiadlo said.
After drying the glass slide, it is immersed
in the PDDA solution for five minutes, fol-
lowed by a rinse or two minutes. Then, after
drying it, the glass slide is immersed into the
negatively charged of clay nanoplatelets for
10 minutes, followed by a rinse once again.
After repeating the cycles 50 to 200 times,
Podsiadlo said he is able to achieve a thickness
of one to four microns. In order to remove the
nacre film from the glass slide the research-
ers immerse the glass slide into hydrofluoric
acid, which dissolves the surface of the glass
slide beneath the composite, thus releasing
the nacre film, Podsiadlo said.
The result of this layer-by-layer deposi-
tion process is an ordered "brick-and mor-
tar-arrangement," due to which the film
exhibits high-strength properties. When
stress is applied to the artificial nacre, the

nacre film with 50 cycles of deposition per-
forms as well as natural nacre.
Possessing high-strength and the poten-
tial to be used in different industries
this material has a promising future.
In biomedical applications, Kotov said,
"we could fabricate implantable medical
devices coated with nacre, which would
be biocompatible."
By making medical devices more bio-
compatible with the human body, Kotov
said the devices would be safer for use and
create less strain for the patient.
Kotov's team is also working with a few
defense contractors with whom they have
different levels of collaboration.
The University research team has a close
collaboration with Nomadics Inc., a defense
contractor based in Stillwater, Okla. Togeth-
er, they are developing several Homeland
Security initiatives, which involve the use of
artificially synthesized nacre" Kotov said.
In the future, Kotov said he believes
that the artificially synthesized nacre can
be strengthened by replacing PDDA with
another polymer called Chitosan, which is
70 times stronger than PDDA.
The next step of the team's research
aims to utilize Chitosan. Also, Kotov
plans to lower the films' thermal con-
ductivity, to increase the films ability to
disperse heat, which would also increase
its potential use. Kotov said that in about
two years, we should be able to see objects
either made entirely of or coated with arti-
ficially synthesized nacre being used in
our society.

Last Thursday, a portal to one of the
coldest places in the universe was opened
at the University when a Physics Nobel
Laureate, Wolfgang Ketterle, explained
his pioneering research on ultra-cold
forms of matter.
Ketterle, a Physics professor at the Mas-
sachusetts Institutive of Technology, was
the speaker at the University's fifth annual
Ford Motor Company Distinguished Lec-
ture in Physics event. In 2001, Ketterle was
awarded the Nobel Prize in Physics for his
co-discovery and experiments involving
Bose-Einstein condensation.
The original theory for this process was
the result of the combined work of phy-
scist Satyendra Bose and Albert Einstein.
Expanding on a theory sent to him from
Bose, Einstein predicted the existence of
the Bose-Einstein Condensate. For sev-
enty years this prediction was left unveri-
fied until 1995, which was when Ketterle
observed this form matter.
"Without exaggeration these are the cold-
est matter in the universe," Ketterle said.
In Bose-Einstein condensation experi-
ments, gases are cooled to a temperature
close to absolute zero. "If you go down lower
and lower in temperature, particles slow
down and eventually lose all their energy
and that is called absolute zero," he added.
As a result of this cold environment, the
gas atoms have very little energy left and
they form a "condensate," Ketterle said. In
this type of condensate, different from the
ordinary condensation that gas undergoes
when forming a liquid, the atoms no lon-
ger vibrate independently, but rather act in
unison.
At higher temperatures, atoms can be
thought of as an unorganized platoon of
soldiers each marching to different beats.
When the temperature is lowered to form
a Bose-Einstein condensate, the atoms
behave as a platoon marching in unison.
At this point the individual soldiers - or
atoms - are indistinguishable and act like
a wave rather than individual particles.
Ketterle's Nobel Prize-winning work
included observing this wave nature by
making two Bose-Einstein condensates
overlap. When the two Bose-Einstein con-
densates overlap, they interfere to produce
a characteristic set of peaks and valleys
or "interference pattern." This is simi-
lar to what is observed when two sets of
water waves run into each other - or the

"I think the biggest
impact is that new
knowledge about
matter may allow
us to engineer new
materials, but this
is something more
in the future."
- Wolfgang Ketterle
Physics Nobel Laureate
effect seen when throwing two stones into
a pond at the same time and watching the
ripples propagate.
For decades, scientist thought that it
would be impossible to observe Bose-Ein-
stein condensate in the laboratory. Ket-
terle said, "Bose-Einstein condensation
was regarded as an illusive goal. People
mentioned that it would be wonderful to
get there, but they felt there was no way to
push laser cooling to those limits."
By combining two cooling schemes,
Ketterle was able to push these limits and
help verify the long-time theoretical pre-
diction that this form of matter existed.
This verification has advanced our basic
understanding of matter.
"I think the biggest impact is that new
knowledge about matter may allow us to
engineer new materials, but this is some-
thing more in the future," Ketterle added.
In addition, Ketterle said that studying
the interference patterns of condensates
could prove useful at measuring gravita-
tional and rotational forces, which may
find applications in navigation and geo-
logical explorations.
The lectureship was sponsored by an
endowment given to the University from
the Ford Motor Company. "This gift from
Ford ... allows the department to bring in
world-class visitors to interact with our
students and faculty as well as deliver this
public lecture," said physics department
Chair Myron Campbell at the opening of
the lecture.
Attending the public lecture were a few
hundred students, faculty and associates
of the Ford Motor Company who crowded
the University's East Hall.

COURTESY OF NICHOLAS KOTOV
Microscopic image of the synthetic nacre
University researchers created.

PAST TO PRESENT: POLIO VACCINE REMEMBERED
Continued from page 1

COUNTRIES STILL AFFLICTED BY POLIO

UCOU.TES.OFHfBENLEY sTA C I.L LIBRAuR).
U.S. Sen. Phil Hart of Michigan visits Andrea Cappaert (in Iron Lung).

and especially my mother to tell you
that you can't go swimming in the sum-
mer. 'You can't go in the pool, you might
catch polio,' she told me. I didn't know
what that meant at the time, but it was
very strictly enforced," Lichtenstein said.
"(As a child), every day someone was
worried that I was going to get polio.
From 1916 to 1955, there were an
average of 13,000 cases per year. At the
height of the polio epidemic in 1952,
more than 57,000 Americans - mostly
young children - became infected with
polio. A number that, while significant,
is "not nearly as many as the kids who
got diphtheria or pneumonia or tuber-
culosis," Markel said. These diseases,
however, did not receive nearly as much
media attention or instill as much fear in
the public as polio did.
One reason for this singling out of
polio was because of the visibility and the
general "creepiness" of the disease's most
serious symptom, paralysis, Markel said.
While the majority of those infected
exhibit no symptoms, the virus occa-
sionally leaves its victim paralyzed from
the waist down, unable to walk. Even
more rarely, victims of the disease are
paralyzed from the neck down, unable to
breath without mechanical aid.
During the polio epidemic of the first
half of the century, this meant being
confined for months in the dreaded "iron
lung" - a giant metal machine that sur-
rounds a patient and helps him breath.
Although rare, the pictures of the tiny
heads of children sticking out of these
giant metal coffins left an indelible mark
on the American public.
"It was very nightmarish," Markel
said. "There were these horrific images.

You see pictures of kids not being able to
walk (and having) iron leg braces. Then
there were kids who couldn't breath and
were trapped in iron lungs."
And the virus comes seemingly with-
out warning, preceded by symptoms that
could indicate anything from the com-
mon cold to polio, Markel said.
"Your kid complains of a sore throat
or has a low fever and goes to bed; the
next morning that kid wakes up and can't
move his legs," he said. "That's pretty
scary stuff."
MAKING THE VACCINE
In response to this crushing fear, the
medical community launched an all-out
campaign to eradicate the disease. The
effort was spearheaded by the National
Foundation for Infantile Paralysis, an
organization originally founded by

El Polio-Free
Still prevalent
A Reintroduced
into country
E Has circulated
more than 6
months

GRAPHIC BY LINDSEY UNGAR

The end of polio was now in sight, and
the crowd greeted the announcement
with a standing ovation. The next day's
papers and newsreels were filled with
what one New York Herald Tribune car-
toon triumphantly dubbed "The News
From Ann Arbor."
"People just went nuts," said Medi-
cal History Prof. Howard Markel. "This
achievement was considered by many to
be a godsend."
RELIVING THE PAST
The vaccine was a godsend, because
the virus it promised to eradicate seemed
to many Americans to be sent straight
from hell.
Polio attacks the central nervous sys-
tem, destroying nerve cells and can lead

to paralysis or death. Most of its victims
are young children, though polio's effects
can last a lifetime.
From the 1920s to the early 1950s,
polio was at the front of every parents'
mind, and fear of the disease sometimes
bordered on panic - especially in the
summer when the number of cases sky-
rocketed.
Newspapers printed weekly tallies of
polio cases, while public beaches and
pools were closed in areas that experi-
enced outbreaks.
Richard Lichtenstein, the associate
dean for academic affairs at the School
of Public Health remembers how this fear
paralyzed more than just polio's victims
during his childhood.
"It was pretty common for parents,

I

Franklin D. Roosevelt - a polio vic-
tim. The Foundation's media-heavy
approach later became the model for the
campaigns against cancer and AIDS,
said Markel. "(The Foundation) pio-
neered things like the telethon, celeb-
rity endorsements. They invented the
poster child," Markel said.
In 1948, the Foundation funded Salk
who was working in Pittsburgh at the
time. Six years and a number of smaller
studies later, Salk believed his vaccine to
be ready for a larger trial in 1954.
Using recent advances in technology,
Salk developed a vaccine based on a tech-
nique he used years earlier when working

on influenza. It relied on injecting dead,
harmless polio virus into the body, thus
allowing its immune system to adapt to
the disease and defend the body against
attack from the dangerous, live virus.
But Salk had to proceed with cau-
tion: Two earlier vaccines had noto-
riously failed, including one that
actually infected recipients with
polio rather than granting immunity
to the virus. In order to avoid a simi-
lar fiasco, an enormous trial would
need to be conducted to determine
with certainty the efficacy and safety
of the vaccine.
See POLIO, Page 7

Thomas Francis, left, and Jonas Salk at
an April 12, 1955 Press Conference.

TE- STORAeGf Eo Hu.enS
THE STORA GE CHEST

Teachers of Cofor 1ob Fair
Career Opportunities in Independent Schools
April 17, 2005
2:00 - 5:00 pm
Visit www.greenhillsschool.org/jobfair

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