#Inexpensive new carbon-based catalysts can be tuned fine Researchers at MIT and Lawrence Berkeley National Laboratory have developed a new type of catalyst that can be tuned to promote desired chemical reactions,
potentially enabling the replacement of expensive and rare metals in fuel cells. The new catalyst is based carbon,
made of graphite with additional compounds bonded to the edges of two-dimensional sheets of graphene that make up the material.
the Journal of the American Chemical Society("Graphite-Conjugated Pyrazines as Molecularly Tunable Heterogeneous Electrocatalysts"),by MIT assistant professor of chemistry Yogesh Surendranath and three collaborators.
Catalysts enhance the rate of a chemical reaction but are consumed not in the process. As a result, the repeated action of very small amounts of a catalyst can have large and long-lasting effects.
which are crucial for enabling reactions in devices such as fuel cells or electrolyzers. Molecular electrocatalysts have the advantage of being relatively easy to tune by chemical treatment
His team was able to accomplish that by taking graphite and finding a way to chemically modify its surface to give it the desired tunability.
which is he universal electrode materialin batteries and fuel cells, Surendranath says. By finding a way to make this material tunable in the same ways as molecular catalysts
the researchers are providing an opening to a new approach to the design of such materials,
In addition to their possible uses in fuel cells, such new catalysts could also be useful for enhancing chemical reactions,
This could reduce emissions of a principal greenhouse gas that fosters climate change, and transform it into a useful, renewable fuel.
One frequent barrier to taking systems that work in the laboratory and making them into practical, marketable products is the ability to scale up the production process. ou need to be able to scale efficiently,
for commodities like paint and rubber, should make scaling up their process relatively straightforward, he says:
#Nanocapsule able to protect nutrients in beverages and food supplements Researchers at the National University of Mexico (UNAM) developed a nanostructured system capable of protecting the active compounds of juices and nutritional supplements from high temperatures during the pasteurization process,
in order to retain their nutritional properties. Maria de la Luz Zambrano Zaragoza, researcher at the Nanotechnology area, explained that the benefits of the development called"Nanostructured systems as thermal protectors of functional ingredients in foods"are maintaining the natural compounds,
"and what you read on the label is really present during the storage time of the product before its expiration date."
a pigment found in plants, fruits and vegetables that can be used as an antioxidant.""The aim was to analyze
if by placing a protective layer surrounding the beta-carotene, it lost less nutritional properties during pasteurization;
so we designed nanocapsules measuring less than 500 nanometers, and made a gum-like model that has a liquid center.
In our case the gum wall is a biodegradable polymer that protects the liquid center:
beta carotene,"said the responsible for the academic research. These nanocapsules would be added to the commercial drink.
The consumption of the system designed in the Laboratory of Transformation and Emerging Technologies in Food has no contraindications,
Besides being composed of a biodegradable polymer, it becomes a lactic acid and can easily be discarded.""We tested it in orange, strawberry and watermelon juice at 70 and 90 Degree celsius,
"said the university academic. In addition to improving retention of betacarotene in thermal processes, the use of nanocapsules can be applied to other antioxidants in processes such as sterilization or UHT.
The research received the second place in the award of the"Programme for the Promotion of Patenting and Innovation"(PROFOPI 2014-2015) in Mexico
which aims to promote the culture of industrial property in the university. This scientific development is in the process of patenting.
The benefit obtained by using the nanostructured food system is less addition of active substances usually required during production,
Scientists at the U s. Department of energy (DOE)' s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have devised an ultra-thin invisibility"skin"cloak that can conform to the shape
Working with brick-like blocks of gold nanoantennas, the Berkeley researchers fashioned a"skin cloak"barely 80 nanometers in thickness,
that was wrapped around a three-dimensional object about the size of a few biological cells and arbitrarily shaped with multiple bumps and dents.
director of Berkeley Lab's Materials sciences Division and a world authority on metamaterials-artificial nanostructures engineered with electromagnetic properties not found in nature."
and is a member of the Kavli Energy Nanosciences Institute at Berkeley (Kavli ENSI), is the corresponding author of a paper describing this research in Science("An ultrathin invisibility skin cloak for visible light").
"It is the scattering of light-be infrared it visible , X-ray, etc.,-from its interaction with matter that enables us to detect
The rules that govern these interactions in natural materials can be circumvented in metamaterials whose optical properties arise from their physical structure rather than their chemical composition.
For the past ten years, Zhang and his research group have been pushing the boundaries of how light interacts with metamaterials,
In the past, their metamaterial-based optical carpet cloaks were bulky and hard to scale up and entailed a phase difference between the cloaked region
"Creating a carpet cloak that works in air was so difficult we had embed to it in a dielectric prism that introduced an additional phase in the reflected light,
a recent member of Zhang's research group who is now an assistant professor at Penn State university."
however, allow us to manipulate the phase of a propagating wave directly through the use of subwavelength-sized elements that locally tailor the electromagnetic response at the nanoscale,
300 square microns in area that was wrapped conformally in the gold nanoantenna skin cloak, the light reflected off the surface of the skin cloak was identical to light reflected off a flat mirror,
"or"off"simply by switching the polarization of the nanoantennas.""A phase shift provided by each individual nanoantenna fully restores both the wavefront
and the phase of the scattered light so that the object remains perfectly hidden, "says co-lead author Zi Jing Wong, also a member of Zhang's research group.
and metamaterials offers tantalizing future prospects for technologies such as high resolution optical microscopes and superfast optical computers.
invisibility cloaks could prove useful for 3d displays s
#Physicists discover spiral vortex patterns from electron waves In their new study("Electron Vortices in Photoionization by Circularly Polarized Attosecond Pulses),
By firing two time-delayed, ultrashort laser pulses at a helium atom, the researchers found that the distribution of momentum values for these intersecting electron waves can take the form of a two-armed vortex that resembles a spiral galaxy.
a George Holmes University Professor of physics. ou don have to do this on the fly. aving a way to know what youe inputting into an unknown situation is important.
If youe a doctor (examining) a patient you have to know the properties of (your instruments)
Like all light, laser pulses feature electric fields that normally point in many directions. Polarizing a laser pulse aligns these fields along one direction,
research assistant professor of physics. sing attosecond pulses, the pattern is clearly visible. Offering their peers new tools,
#3d printed guide helps regrow complex nerves after injury A team of researchers has developed a first-of-its-kind,
3d printed guide that helps regrow both the sensory and motor functions of complex nerves after injury.
The groundbreaking research has the potential to help more than 200,000 people annually who experience nerve injuries or disease.
Collaborators on the project are from the University of Minnesota, Virginia Tech, University of Maryland, Princeton university, and Johns hopkins university.
Because of this complexity, regrowth of nerves after injury or disease is very rare according to the Mayo Clinic.
Nerve damage is often permanent. Advanced 3d printing methods may now be the solution. This is a 3-D printed nerve regeneration pathway implanted in a rat helped to improve walking in 10 to 12 weeks after implantation.
University of Minnesota College of Science and Engineering) In a new study, published today in the journal Advanced Functional Materials("3d printed Anatomical Nerve Regeneration Pathways),
and 3d printing techniques to create a custom silicone guide implanted with biochemical cues to help nerve regeneration.
"This represents an important proof of concept of the 3d printing of custom nerve guides for the regeneration of complex nerve injuries,
"said University of Minnesota mechanical engineering professor Michael Mcalpine, the study's lead researcher.""Someday we hope that we could have a 3d scanner
and printer right at the hospital to create custom nerve guides right on site to restore nerve function."
or cadavers that hospitals could use to create closely matched 3d printed guides for patients s
#Darwin on a chip Researchers of the MESA+Institute for Nanotechnology and the CTIT Institute for ICT Research at the University of Twente in The netherlands have demonstrated working electronic circuits that have been produced in a radically new way,
The findings promise a new generation of powerful, energy-efficient electronics, and have been published in the leading British journal Nature Nanotechnology("Evolution of a Designless Nanoparticle Network into Reconfigurable Boolean logic").
"Learning from Nature One of the greatest successes of the 20th century has been the development of digital computers.
During the last decades these computers have become more and more powerful by integrating ever smaller components on silicon chips.
However, it is becoming increasingly hard and extremely expensive to continue this miniaturisation. Current transistors consist of only a handful of atoms.
It is a major challenge to produce chips in which the millions of transistors have the same characteristics,
and thus to make the chips operate properly. Another drawback is that their energy consumption is reaching unacceptable levels.
It is obvious that one has to look for alternative directions and it is interesting to see what we can learn from nature.
Natural evolution has led to powerful omputerslike the human brain, which can solve complex problems in an energy-efficient way.
Nature exploits complex networks that can execute many tasks in parallel. Moving away from designed circuits The approach of the researchers at the University of Twente is based on methods that resemble those found in Nature.
They have used networks of gold nanoparticles for the execution of essential computational tasks. Contrary to conventional electronics, they have moved away from designed circuits.
By using'designless'systems costly design mistakes are avoided. The computational power of their networks is enabled by applying artificial evolution.
This evolution takes less than an hour, rather than millions of years. By applying electrical signals,
one and the same network can be configured into 16 different logical gates. The evolutionary approach works around-or can even take advantage of-possible material defects that can be fatal in conventional electronics.
Powerful and energy-efficient It is the first time that scientists have succeeded in this way in realizing robust electronics with dimensions that can compete with commercial technology.
According to prof. Wilfred van der Wiel the realized circuits currently still have limited computing power. ut with this research we have delivered proof of principle:
demonstrated that our approach works in practice. By scaling up the system, real added value will be produced in the future.
Take for example the efforts to recognize patterns, such as with face recognition. This is very difficult for a regular computer,
while humans and possibly also our circuits can do this much better.""Another important advantage may be that this type of circuitry uses much less energy, both in the production,
and during use. The researchers anticipate a wide range of applications, for example in portable electronics and in the medical world l
#Proteins assemble and disassemble on command Scientists have deciphered the genetic code that instructs proteins to either self-assemble
or disassemble in response to environmental stimuli, such as changes in temperature, salinity or acidity. The discovery provides a new platform for drug delivery systems and an entirely different view of cellular functions.
The advance was made by researchers at Duke university and is the first time that scientists have reported the ability to create biological structures that are programmed readily to assemble
and disassemble. With this knowledge in hand, researchers have opened a new world for designer proteins and investigations into nanotechnology
biotechnology and medical treatments. The study appears September 21 in Nature Materials("Sequence Heuristics To Encode Phase Behaviour In Intrinsically Disordered Protein Polymers"."
""The very simple design rules that we have discovered provide a powerful engineering tool for many biomedical
and biotechnology applications,"said Ashutosh Chilkoti, chair of the Department of Biomedical engineering at Duke.""We can now,
with a flick of a switch and a temperature jump, make a huge range of biological molecules that either assemble or disassemble."
"The study investigated several triggers that can cause protein structures to assemble or break apart, but it primarily focused on heat.
Protein-based structures that self-assemble when heated and remain stable inside of the bloodstream have long been used in a variety of applications.
The opposite behavior, however, has eluded long researchers, especially outside of the carefully controlled environment of a chemistry lab."
"Nobody has been able to make these kinds of materials with the degree of complexity that we have demonstrated now,
"said Felipe Garcia Quiroz, a former graduate student in Chilkoti's laboratory and first author of the new study.
Chilkoti's lab has designed self-assembling proteins for drug delivery systems for several years. Simply by adding heat
however, drugs could be encapsulated in protein cages that accumulate inside of a tumor and dissolve once heated.
they could break down into additional therapeutic agents. We can now design two things into one."
Because the laboratory identified the genetic sequences that encode this behavior, they were able to point out a long list of human proteins that likely exhibit it."
"These findings will be exciting to both the materials science and the biochemistry communities,"said Quiroz.""They'll be able to push the limits of what we know about these kinds of materials
and then go back to explore how biology is already making use of them
#A thermal invisibility cloak actively redirects heat Light, sound, and now, heat--just as optical invisibility cloaks can bend
and diffract light to shield an object from sight, and specially fabricated acoustic metamaterials can hide an object from sound waves,
a recently developed thermal cloak can render an object thermally invisible by actively redirecting incident heat.
The system, designed by by scientists at the Nanyang Technological University (NTU) in Singapore, has the potential to fine-tune temperature distribution
and heat flow in electronic and semiconductor systems. It has application in devices with high requirements for efficient dissipation and homogenous thermal expansion
such as high-power engines, magnetic resonance imaging (MRI) instruments, and thermal sensors.""Because of its shape flexibility, the active thermal cloak might also be applied in human garments for effective cooling and warming,
which makes a lot of sense in tropical areas such as Singapore, "said Prof. Baile Zhang of NTU.
Zhang and colleagues had been experimenting with metamaterials, artificial composites that exhibit properties not found in naturally occurring substances.
They had designed previously a metamaterial thermal cloak that passively guided conductive heat around a hidden object.
That device lacked an on/off switch and could not be adapted to objects of varying geometries."
whether we can control thermal cloaking electrically, not by guiding heat around the hidden object passively with traditional metamaterials,
which are controlled semiconductor heat pumps by an external input voltage, around a 62-millimeter diameter air hole in a carbon steel plate just 5 mm thick.
that can be used to shield sensitive electronic components from heat dissipation. Additionally, the researchers found that their active thermal cloaking was limited not by the shape of the object being hidden.
Looking ahead, Zhang and his colleagues plan to apply the thermal cloaks in electronic systems, improving the efficiency of heat transfer,
#Protein-based sensor could detect viral infection or kill cancer cells MIT biological engineers have developed a modular system of proteins that can detect a particular DNA sequence in a cell
and then trigger a specific response, such as cell death. This system can be customized to detect any DNA sequence in a mammalian cell
says James Collins, the Termeer Professor of Medical Engineering and Science in MIT Department of Biological engineering and Institute of Medical Engineering and Science (IMES).
To achieve this, the researchers could program the system to produce proteins that alert immune cells to fight the infection,
a professor of biotechnology and bioengineering at The swiss Federal Institute of technology in Zurich, described this experiment as an legant proof of conceptthat could lead to greatly improved treatments for viral infection. entinel designer cells engineered with the DNA sense
This would represent a quantum leap in antiviral therapy, says Fussenegger, who was involved not in the study.
While treating diseases using this system is likely many years away, it could be used much sooner as a research tool,
whether genetic material has been delivered successfully to cells that scientists are trying to genetically alter. Cells that did not receive the new gene could be induced to undergo cell death,
or to study the 3-D structure of normal chromosomes by testing whether two genes located far from each other on a chromosome fold in such a way that they end up next to each other,
the researchers say
#New frontiers in 3d printing Three dimensional printing is revolutionizing the production of new devices and structures, including soft robots,
flexible electronics and engineered tissue replacements, but advances have been challenged by the inherent complexity of integrating multiple materials.
Now, breaching the next frontier in 3d printing, Jennifer A. Lewis, Sc. D.,has designed new systems to actively mix
for the first time, allow for the simultaneous control of composition and geometry during printing. Lewis is a Core Faculty member at the Wyss Institute for Biologically Inspired Engineering at Harvard university and the Hansjörg Wyss Professor of Biologically Inspired Engineering at the Harvard John A. Paulson School of engineering and Applied sciences (SEAS.
The goal of integrating different material and structural properties within printed objects has demanded the invention of new, flexible printing platforms.
For example, to print a functional"wearable device including its electronic components, a 3d printer would need to seamlessly transition from the flexible material that moves with the wearer joints to the rigid material that holds the electronic components.
It would also need to embed electrical circuitry with multiple inks of varying conductivity and resistivity,
precisely switching between them. And, it would be ideal to do all of this inside one continuous print job with active mixing of complex fluids.
This method works well with thin, flowing fluids with low-viscosity, but is ineffective with thicker, high-viscosity fluids like gels, especially in small volumes over short periods of time.
Lewis and her team designed a new multimaterial printhead based on active mixing, Her team included Thomas Ober, former Postdoctoral Research Scholar at the Wyss Institute and SEAS;
The work was published September 21 in The Proceedings of the National Academy of Sciences (PNAS.""Passive mixtures don guarantee perfectly mixed materials,
These structures may find potential application in flexible electronics, wearable devices, and soft robotics. They also printed reactive materials,
. who is the Judah Folkman Professor of Vascular Biology at Harvard Medical school and Boston Children's Hospital as well as Professor of Bioengineering AT SEAS."
In addition to Hardin, the work included Ober, former SEAS Postdoctoral Research Fellow and current Wyss Staff Scientist Alexander Valentine,
This is a crucial step in creating a new generation of foldable electronics-think a flat-screen television that can be rolled up for easy portability-and implantable medical devices.
The work, published Monday in the Proceedings of the National Academy of Sciences("Fatigue-free, superstretchable, transparent,
and biocompatible metal electrodes"),pairs gold nanomesh with a stretchable substrate made with polydimethylsiloxane, or PDMS.
The substrate is stretched before the gold nanomesh is placed on it-a process known as"prestretching "-and the material showed no sign of fatigue
The gold nanomesh also proved conducive to cell growth, indicating it is a good material for implantable medical devices.
Fatigue is a common problem for researchers trying to develop a flexible, transparent conductor, making many materials that have good electrical conductivity,
flexibility and transparency-all three are needed for foldable electronics-wear out too quickly to be practical,
said Zhifeng Ren, a physicist at the University of Houston and principal investigator at the Texas Center for Superconductivity,
who was the lead author for the paper. The new material, produced by grain boundary lithography,
In materials science,"fatigue"is used to describe the structural damage to a material caused by repeated movement or pressure, known as"strain cycling."
That means the materials aren't durable enough for consumer electronics or biomedical devices.""Metallic materials often exhibit high cycle fatigue,
and fatigue has been a deadly disease for metals, "the researchers wrote.""We weaken the constraint of the substrate by making the interface between the Au (gold) nanomesh and PDMS slippery,
and expect the Au nanomesh to achieve superstretchability and high fatigue resistance, "they wrote in the paper."
"Free of fatigue here means that both the structure and the resistance do not change or have little change after many strain cycles."
"the Au nanomesh does not exhibit strain fatigue when it is stretched to 50 percent for 10,000 cycles."
The researchers used mouse embryonic fibroblast cells to determine biocompatibility; that, along with the fact that the stretchability of gold nanomesh on a slippery substrate resembles the bioenvironment of tissue
or organ surfaces, suggest the nanomesh"might be implanted in the body as a pacemaker electrode,
a connection to nerve endings or the central nervous system, a beating heart, and so on, "they wrote. Ren's lab reported the mechanics of making a new transparent and stretchable electric material,
using gold nanomesh, in a paper published in Nature Communications in January 2014. This work expands on that,
producing the material in a different way to allow it to remain fatigue-free through thousands of cycles s
#Physicists determine the three-dimensional positions of individual atoms for the first time Atoms are the building blocks of all matter On earth,
a UCLA professor of physics and astronomy and a member of UCLA California Nanosystems Institute, is published Sept. 21 in the online edition of the journal Nature Materials("Three-dimensional coordinates of individual atoms
in materials revealed by electron tomography")."For more than 100 years, researchers have inferred how atoms are arranged in three-dimensional space using a technique called X-ray crystallography,
which involves measuring how light waves scatter off of a crystal. However, X-ray crystallography only yields information about the average positions of many billions of atoms in the crystal,
and not about individual atomsprecise coordinates. t like taking an average of people On earth, Miao said. ost people have a head, two eyes, a nose and two ears.
But an image of the average person will still look different from you and me.
Because X-ray crystallography doesn reveal the structure of a material on a per-atom basis
when the materials are components of machines like jet engines. oint defects are very important to modern science and technology,
scanning transmission electron microscopes only produce two-dimensional images. So creating a 3-D picture requires scientists to scan the sample once,
and re-scan it repeating the process until the desired spatial resolution is achieved before combining the data from each scan using a computer algorithm.
Using a scanning transmission electron microscope at the Lawrence Berkeley National Laboratory Molecular Foundry, Miao and his colleagues analyzed a small piece of tungsten,
said Peter Ercius, a staff scientist at Lawrence Berkeley National Laboratory and an author of the paper.
thanks to the electron beam energy being kept below the radiation damage threshold of tungsten. Miao and his team showed that the atoms in the tip of the tungsten sample were arranged in nine layers, the sixth
which will help inform our understanding of the properties of these important materials at the most fundamental scale. think this work will create a paradigm shift in how materials are characterized in the 21st century,
and are discussed in many physics and materials science textbooks. Our results are the first experimental determination of a point defect inside a material in three dimensions. f
#Permanent data storage with light The first all-optical permanent on-chip memory has been developed by scientists of Karlsruhe Institute of technology (KIT) and the universities of Münster, Oxford, and Exeter.
This is an important step on the way towards optical computers. Phase change materials that change their optical properties depending on the arrangement of the atoms allow for the storage of several bits in a single cell.
With optical elements, computers can work more rapidly and more efficiently. Optical fibers have long since been used for the transmission of data with light.
But on a computer, data are processed still and stored electronically. Electronic exchange of data between processors and the memory limits the speed of modern computers.
To overcome this so-called Von neumann bottleneck, it is not sufficient to optically connect memory and processor,
as the optical signals have to be converted into electric signals again. Scientists, hence, look for methods to carry out calculations and data storage in a purely optical manner.
Scientists of KIT the University of Münster, Oxford university, and Exeter University have developed now the first all-optical,
nonvolatile on-chip memory. ptical bits can be written at frequencies of up to a gigahertz. This allows for extremely quick data storage by our all-photonic memory,
Professor Wolfram Pernice explains. Pernice headed a working group of the KIT Institute of Nanotechnology (INT)
and recently moved to the University of Münster. he memory is compatible not only with conventional optical fiber data transmission,
but also with latest processors, Professor Harish Bhaskaran of Oxford university adds. The new memory can store data for decades even
when the power is removed. Its capacity to store many bits in a single cell of a billionth of a meter in size multilevel memory) also is highly attractive.
Instead of the usual information values of 0 and 1, several states can be stored in an element
and even autonomous calculations can be made. This is due to so-called phase change materials, novel materials that change their optical properties depending on the arrangement of the atoms:
Within shortest periods of time, they can change between crystalline (regular) and amorphous (irregular) states.
For the memory, the scientists used the phase change material Ge2sb2te5 (GST. The change from crystalline to amorphous (storing data) and from amorphous to crystalline (erasing data) is initiated by ultrashort light pulses.
For reading out the data, weak light pulses are used. Permanent all-optical on-chip memories might considerably increase future performance of computers
and reduce their energy consumption. Together with all-optical connections, they might reduce latencies. Energy-intensive conversion of optical signals into electronic signals and vice versa would no longer be required
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