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Image: Albert Einstein College of Medicine
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Issue no. 26, 2011
Published: Jul 22, 2011 |
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 New fluorescent protein makes internal organs visible | | Toilet research funded by Bill Gates foundation | | Light propagates as if 'space is missing' | | Artificial leaves make fuel from sunlight | | Pure nanotubes by the kilo | | European team creates robotic octopus | | Computers understand hand-waving descriptions | | Anticensorship software to help rebels get the word out | | It's tough at the top for alpha males |
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| New fluorescent protein makes internal organs visible |
Researchers at Albert Einstein College of Medicine of Yeshiva University
have developed the first fluorescent protein that enables scientists to
clearly 'see' the internal organs of living animals without the need for
a scalpel or imaging techniques that can have side effects or increase
radiation exposure.
The new probe could prove to be a breakthrough in whole-body imaging -
allowing for example doctors to monitor the growth of tumours in order to
assess the effectiveness of anti-cancer therapies. In contrast to other
body-scanning techniques, fluorescent-protein imaging does not involve
radiation exposure or require the use of contrast agents.
For the past 20 years scientists have used a variety of coloured
fluorescent proteins, derived from jellyfish and corals, to visualize
cells and their organelles and molecules. But using fluorescent probes
to peer inside live mammals has posed a major challenge. This is because
haemoglobin effectively absorbs the blue, green, red and other
wavelengths used to stimulate standard fluorescent proteins along with
any wavelengths emitted by the proteins when they do light up.
The Yeshiva researchers engineered a fluorescent protein from a
bacterial phytochrome. This new protein, dubbed iRFP, both absorbs and
emits light in the near-infrared portion of the electromagnetic
spectrum. The researchers targeted their fluorescent protein to the
liver - an organ particularly difficult to visualize. Adenovirus
particles containing the gene for iRFP were injected into mice. Once the
viruses and their gene cargoes infected liver cells, the infected cells
expressed the gene and produced iRFP protein. The mice were then exposed
to near-infrared light and it was possible to visualize the resulting
emitted fluorescent light using a whole-body imaging device. |
| MedicalXpress / Nature Biotechnology
Jul 18, 2011 |
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| Toilet research funded by Bill Gates foundation |
Cheap, waterless toilets that can turn human waste into clean water and
fertilizer within 24 hours are being designed and built by eight
engineering teams around the world.
The goal of the Bill & Melinda Gates Foundation's USD 3m Reinventing the
Toilet Challenge is to bring affordable, sustainable human waste
treatment to the 2.6bn people in the developing world - about 40% of the
world's population - who have no access to flush toilets. That, in turn,
is expected to reduce the number of children who die each year of
diarrheal diseases - a figure reported to be around 1.5m.
The Reinventing the Toilet Challenge was announced by the Gates
Foundation Tuesday in Kigali, Kenya, at the 2011 AfricaSan Conference,
which focuses on sanitation and hygiene. It was among USD 42m in new
grants from the foundation targeting sanitation and clean water.
The toilet cannot be hooked up to water, sewage or power lines and must
cost less than five cents per user per day. It must convert urine and
faeces into clean water, mineral ash fertilizer, CO2 and energy. The
ability to treat waste within 24 hours is important because most
existing 'green' toilets rely on composting, which takes a long time.
Besides the waste processing itself, the teams also need to makes sure
the toilet is safe and robust. Developers also face cultural challenges. |
| CBC News
Jul 20, 2011 |
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| Light propagates as if 'space is missing' |
Researchers in the UK and the US have crafted an optical nanostructure
that allows light to pass through without accumulating a phase change -
as if the medium were completely missing in space. The device could find
applications in optoelectronics, they say, for instance as a way of
transporting signals without allowing information to become distorted.
Whenever light travels through a medium it experiences a phase-shift, as
individual oscillations become out of phase with each other. In certain
optics applications, including interferometers, these phase variations
can introduce an unwanted dispersion of frequencies. This effect can
lead to phase distortions, which ultimately reduce the quality of
signals. But now the team has found a way around this issue. They have
designed a way to control the dispersion of light by manufacturing a
metamaterial that has with a refractive index of zero.
The device includes photonic crystals, which are materials with a
periodic variation of the dielectric constant, resulting in a photonic
band gap. The team fabricated photonic crystals with the unusual
property of having a negative refractive index. One outcome of this
optical property - not found anywhere in nature - is that the phase of
light travelling through the photonic crystal flows in the opposite
direction to the flow of energy.
The device consists of alternating layers, roughly 2 µm thick, of these
photonic crystals along with positive index materials. The result is
that the phase of light keeps oscillating but when it emerges from the
device is has undergone zero overall phase change. |
| PhysicsWorld / Nature Photonics
Jul 18, 2011 |
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| Artificial leaves make fuel from sunlight |
Two teams of researchers in the US have taken important steps towards
the creation of commercially viable 'artificial leaf' - a hypothetical
device that can turn sunlight into electrical energy or fuel by
mimicking some aspects of photosynthesis.
Both teams made their devices from silicon wafers that are coated with
catalytic metals and protective layers. The solar cells are about the
size of a credit card and can capture sunlight and then use the energy
to split water into its constituent oxygen and hydrogen. This is
different to conventional cells, which convert light directly into
electricity. With these new devices, the ultimate plan is to recombine
the two gases in an integrated fuel cell, thus converting the chemical
energy to electrical energy. Producing fuel rather than electricity has
the advantage that the fuel can be easily stored until it is needed.
Both artificial leaves use a silicon n-p junction: a bilayer of n-type
and p-type silicon. An incident photon is absorbed to create an
electron-hole pair in the semiconductor. The electrons migrate to the
n-side and the holes to the p-side. The holes then drive the splitting
of water in a process mediated by the outermost layer of the cell, which
is a photocatalyst. Unlike some of the exotic photocatalysts used in
earlier devices, the catalyst in these new devices are made of cobalt
phosphate, which is an abundant and cheap material.
The main challenge was how to prevent the silicon from reacting with the
water. The two teams took different approaches to the problem. One group
used the catalyst itself as a protective layer, binding a thin film of
pure cobalt firmly to the silicon before converting it to the phosphate
form. The other team used a thin film of conductive indium tin oxide in
front of the p-type silicon as the protective layer. |
| PhysicsWorld
Jul 20, 2011 |
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| Pure nanotubes by the kilo |
An improved process for making large amounts of pure metallic carbon
nanotubes could hold the key to overhauling the electrical power grid
with more efficient transmission lines. Researchers at Rice University
in Houston plan to generate a large quantity of this material by the end
of summer. They'll use these nanotubes to make long and highly
conductive fibres that could be woven into more efficient electrical
transmission lines.
There are a few different classes of carbon nanotube, each with slightly
different properties and different potential uses. Unfortunately,
existing production methods result in a mixture of different nanotubes,
with varying dimensions and different electrical properties. Purely
semiconducting nanotubes, useful for future integrated circuits, are in
the mix with metallic nanotubes that could be used to make highly
conductive wires. So nanotubes have to be separated by type, a slow and
expensive process.
The Rice team has now improved on a method for making pure nanotubes
that they first developed in 2006. Called 'amplification', it should
eventually allow them to turn a nanogram of pure carbon nanotubes into a
gram, then a kilogram, then a ton. They start by separating a small
amount of pure metallic nanotubes from a mixture, and then attach a
catalyst to the tip of each tube. They then put the nanotubes into a
pressurized, temperature-controlled chamber and feed in a mixture of
gases. The nanotubes double in size, growing from the catalyst at the
tip. The existing nanotube acts as a template that dictates the
diameter, structure, and properties of the extra length of the nanotube.
The nanotubes are then cut and the process is repeated.
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| Technology Review
Jul 21, 2011 |
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| European team creates robotic octopus |
One day a giant robotic octopus might save your life. That is one of the
applications a team of European scientists thinks its robotic octopus
could have beyond navigating underwater and grasping objects. Recently
they took the first step by creating a robotic octopus arm. The arm is
part of a larger interdisciplinary European project funded by the
European Commission to create a functional full-body octopus robot.
Creating functional soft robots is an enormous challenge because most
engineering is based on rigid materials, while the technologies for
building compliant structures are not as well developed. Other
bio-inspired soft robots have locomotion, but they cannot grasp and
manipulate objects like an octopus. An octopus has a musculature that is
unusual in nature and typically found only in tongues and elephant
trunks. The European team studied the octopus' movement and found that
in order to push, the arms shorten and elongate.
Their robotic prototype is about 45cm long and modelled after a real
octopus that inhabits the Mediterranean. The waterproof arm is made from
silicone and embedded with a steel cable anchored to a set of nylon
cables. By manipulating the cable, the arm can grasp objects. There is
enough friction from the silicone exterior that sucker-like components
were not needed.
Although the Octopus Project didn't start with specific application
goals, such a robot could have a number of uses. A team of British
surgeons is interested in applying the technology to an endoscope that
turns from a soft tool into a hard one that can perform surgery. |
| MSNBC / Bioinspiration & Biomimetics
Jul 19, 2011 |
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| Computers understand hand-waving descriptions |
Describing objects is so much easier when you use your hands, the
classic being 'the fish was this big'. For humans, it's easy to
understand what is meant, but computers struggle, and existing
gesture-based interfaces only use set movements that translate into
particular instructions. Now a system called Data Miming can recognise
objects from gestures without the user having to memorise a 'vocabulary'
of specific movements.
Data Miming uses a Microsoft Kinect motion-capture camera to create a 3D
representation of a user's hand movements. Voxels, or pixels in three
dimensions, are activated when users pass their hands through the space
represented by each voxel. And when a user encircles their fingers to
indicate a table leg, say, the system can also identify that all of the
enclosed space should be included in the representation. It then
compares user-generated representations with a database of objects in
voxel form and selects the closest match.
In tests the system correctly recognised three-quarters of descriptions,
and the intended item was in the top three matches from its database 98%
of the time. The system could be incorporated into online shopping so
users could gesture to describe the type of product they want and have
the system make a suggestion. |
| New Scientist
Jul 20, 2011 |
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| Anticensorship software to help rebels get the word out |
State-backed internet censorship is the method of choice for countries
that want to crack down on citizens spreading messages of revolution
online. But now dissidents have a tool to help them fight back. Telex,
developed by computer scientists at the University of Michigan, US and
the University of Waterloo, Canada, transmits information to blocked
websites by piggybacking on uncensored connections with the aid of
friendly foreign internet service providers (ISPs).
Users install the Telex client and then make a secure connection to an
uncensored site outside of the censor's network. The connection looks
normal, but Telex tags the traffic with a secret key. Foreign ISPs in
the network between the client and destination site can look for these
tags and redirect the connection to an anonymising service such as a
proxy server. Using Telex is more robust than using such servers
directly, as censors can block access to a proxy once it is discovered.
The researchers have tested the system by watching YouTube videos in
Beijing, China, despite the site being blocked in that country, but they
say it's not yet ready for real users. One barrier might be the need for
foreign ISPs to install Telex software. 'Widespread ISP deployment might
require incentives from governments,' suggest the researchers -
something that the US government might be interested in given its plans
to provide rebels with an 'internet in a suitcase'. Telex also wouldn't
be able to help during an Egypt-style disconnect, as dissidents must at
least be able to connect to uncensored sites. |
| New Scientist
Jul 19, 2011 |
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| It's tough at the top for alpha males |
If you are feeling envious of your boss's paycheck, a new study confirms
that success comes with high stress, possibly as much as faced by those
who have to struggle to find a bite to eat. The results of nine years of
research on wild baboons suggest that despite perks like easy access to
mates and food, top-ranking males experience similar stress levels as
their lowest-rung counterparts.
Those in the middle showed lower stress than either the top or bottom
ranking males, according to measurements of testosterone and a stress
hormone known as glucocorticoid. Samples were taken from the faeces of a
wild male baboon population in Ambelosi, Kenya. While the stress levels
at the top and bottom were similar, they were likely caused by different
problems.
Alpha baboons spent lots of energy fighting to stay on top and trying to
mate with as many females as possible, while the low-ranking males
expended lots of effort searching for food. Meanwhile, there may be
perks for not reaching quite so high. The second-rate beta males
received about the same amount of attention, in the form of grooming,
from females, but did 'slightly better than predicted' at reaching their
'full reproductive potential', the study's authors write. |
| ABC New / Science
Jul 15, 2011 |
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