September 30, 2015

UMMS scientists identify genes that shut down HIV-1

Heinrich Gottlinger, MD, PhD

Discoveries in Luban, Gottlinger labs point to new strategies for disabling viruses

(September 30, 2015)  A pair of studies in the journal Nature, one by Jeremy Luban, MD, and colleagues in Italy and Switzerland, and the other by Heinrich Gottlinger, MD, PhD, and colleagues; have identified genes that disable HIV-1, suggesting a promising new strategy for battling the virus that causes AIDS.

The studies, published online Sept. 30, show that the host cell membrane proteins SERINC5 and SERINC3 greatly reduce the virulence of HIV-1 by blocking the ability of the virus to infect new cells. HIV-1 encodes a protein called Nef that counteracts the SERINCs. New drugs that target the HIV-1 protein Nef would permit the SERINC proteins to inactivate the virus. The papers will appear in the Oct. 8 Nature print edition.

“It’s amazing, the magnitude of the effect that these proteins have on infectivity,” said Dr. Luban, the David J. Freelander Professor in AIDS Research and professor of molecular medicine. “The SERINC proteins reduce the infectivity of HIV-1 virions by more than 100-fold.”

Jeremy Luban, MD

Dr. Gottlinger, professor of molecular, cell & cancer biology and principal investigator of one of the studies, said, “The ability of HIV to inhibit these SERINC proteins has a profound impact on its capacity to infect other cells. Disrupting this mechanism could be a very powerful strategy for treating HIV and similar viruses that express the Nef protein.”

The studies, each done independently, used different, yet complementary, methodologies to unravel the complex interaction between the HIV-1 protein Nef and the cell surface membrane proteins SERINC5 and SERINC3, both of which are expressed in the immune system’s T cells. Luban, working with former members of his lab Massimo Pizzato, PhD, now of the University of Trento in Italy, and Federico Santoni of the University of Geneva in Switzerland, performed massively parallel sequencing on 31 human cell lines that differed in terms of the magnitude of dependence on Nef for HIV-1 replication. Independently, Gottlinger approached the problem biochemically. Conducting proteomic analysis of purified virions, he was able to identify host cell proteins that Nef regulated.

journal reference (Nature/ Gottlinger) >>

Traveller Daybed

(September 30, 2015)  Is the spirit of the traveller who determines the elements and lines of the daybed Traveller, translating the resting pleasure in unknown places, the fear and at the same time the happiness of a mental journey between day memories or an abstract and imaginary journey in a dream world. Natural and honest materials, as the structure in black painted metal on which to place towels and clothes, the saddle stretched natural leather on the sides, strong but gentle to give the body a comfortable support, and finally the meshed fabric embracing the mattress and cushions, caressing them, as it is simply enough to stand among cared details, even to the other end of the world, to feel the pleasant sensation to be at home.

source >>

Sniffing out cancer with improved ‘electronic nose’ sensors

Scientists design a new way to detect signs of ovarian cancer,
in patients’ breath. Credit: American Chemical Society

(September 30, 2015)  Scientists have been exploring new ways to “smell” signs of cancer by analyzing what’s in patients’ breath. In ACS’ journal Nano Letters, one team now reports new progress toward this goal. The researchers have developed a small array of flexible sensors, which accurately detect compounds in breath samples that are specific to ovarian cancer.

Diagnosing cancer today usually involves various imaging techniques, examining tissue samples under a microscope, or testing cells for proteins or genetic material. In search of safer and less invasive ways to tell if someone has cancer, scientists have recently started analyzing breath and defining specific profiles of compounds in breath samples. But translating these exhaled disease fingerprints into a meaningful diagnosis has required a large number of sensors, which makes them impractical for clinical use. Hossam Haick and colleagues sought to address this problem.

journal reference >>

New electrode gives micro-supercapacitor macro storage capacity

© Anaïs Ferris – LAAS-CNRS
Image obtained from scanning tunneling microscopy
on a porous 3D-gold structure.

(September 30, 2015)  Micro-supercapacitors are a promising alternative to micro-batteries because of their high power and long lifetime. They have been in development for about a decade but until now they have stored considerably less energy than micro-batteries, which has limited their application. Now researchers in the Laboratoire d'analyse et d'architecture des systèmes (LAAS-CNRS)1 in Toulouse and the INRS2 in Quebec have developed an electrode material that means electrochemical capacitors produce results similar to batteries, yet retain their particular advantages. This work was published on September 30, 2015 in Advanced Materials.

With the development of on-board electronic systems3 and wireless technologies, the miniaturization of energy storage devices has become necessary. Micro-batteries are very widespread and store a large quantity of energy due to their chemical properties. However, they are affected by temperature variations and suffer from low electric power and limited lifetime (often around a few hundred charge/discharge cycles). By contrast, micro-supercapacitors have high power and theoretically infinite lifetime, but only store a low amount of energy.

Micro-supercapacitors have been the subject of an increasing amount of research over the last ten years, but no concrete applications have come from it. Their lower energy density, i.e. the amount of energy that they can store in a given volume or surface area, has meant that they were not able to power sensors or microelectronic components. Researchers in the Intégration de systèmes de gestion de l'énergie team at LAAS-CNRS, in collaboration with the INRS of Quebec, have succeeded in removing this limitation by combining the best of micro-supercapacitors and micro-batteries.

journal reference >>

Asteroids Found To Be the Moon’s Main ‘Water Supply’

(September 30, 2015)  Water reserves found on the moon are the result of asteroids acting as “delivery vehicles” and not of falling comets as was previously thought. Using computer simulation, scientists from MIPT and the RAS Geosphere Dynamics Institute have discovered that a large asteroid can deliver more water to the lunar surface than the cumulative fall of comets over a billion year period. Their research is discussed in an article recently published in the journal Planetary and Space Science.

At the beginning of the space age, during the days of the Apollo program, scientists believed the moon to be completely dry. At these earliest stages in satellite evolution, the absence of an atmosphere and the influence of solar radiation were thought enough to evaporate all volatile substances into space. However, in the1990s, scientists obtained data from the Lunar Prospector probe that shook their confidence: the neutron current from the satellite surface was indicative of a larger fraction of hydrogen at the near-surface soil of some regions of the moon, which one could interpret as a sign of the presence of water.   

In order to explain how water could be kept on the moon’s surface, scientists formulated a theory known as “cold traps.” The axis of the moon’s rotation is nearly vertical, which is why in the polar regions there are craters with floors that are never exposed to sunlight. When comets consisting mostly of water ice fall, evaporated water can gravitate into those “traps” and remain there indefinitely, as solar rays do not evaporate it.  

In recent years, lunar missions (the Indian Chandrayan probe, the American LRO, data from the Cassini probe and Deep Impact) have brought scientists two pieces new information. The first is that there are indeed considerate quantities of water and hydroxyl groups in the near-surface soil on the moon. The LCROSS experiment, in which a probe purposely crashed onto the moon resulting in the release of a cloud of gas and dust that was later studied with the use of a spectrometer, directly confirmed the existence of water and other volatile substances. The second piece of new information came when the Russian LEND apparatus mounted on board LRO generated a map of water distribution on the moon’s surface. 

 Temperature of the surface around the southern pole of the moon according to LRO data © NASA.

But this second piece has only partly proven their theory: the map of “cold traps” did not correspond to the map of water deposits. The scientists had to refine the theory, and the idea of “lunar congelation” was proposed. It allowed accepting that “survival” of water ice in the regions exposed to sunlight is possible under a soil blanket. It was also suggested that a substantial part of “water” seen by the probes is implanted solar wind: hydrogen atoms from solar wind react with oxygen atoms and form an unstable “dew” of water molecules and hydroxyl groups. Scientists left the possibility open that water could exist in a bound state, i.e. in hydrated minerals.   

journal reference >>

Invisibility Cloak Might Enhance Efficiency of Solar Cells

A special invisibility cloak (right) guides sunlight past the contacts for current removal
to the active surface area of the solar cell. (Graphics: Martin Schumann, KIT)

(September 30, 2015)  Invisibility Cloak Principle: Material Hides Contact Fingers that Extract Current from Solar Cells and Cover the Active Surface – Measurements Confirm Cloaking Effect

Success of the energy turnaround will depend decisively on the extended use of renewable energy sources. However, their efficiency partly is much smaller than that of conventional energy sources. The efficiency of commercially available photovoltaic cells, for instance, is about 20%. Scientists of Karlsruhe Institute of Technology (KIT) have now published an unconventional approach to increasing the efficiency of the panels. Optical invisibility cloaks guide sunlight around objects that cast a shadow on the solar panel, such as contacts for current extraction. DOI: 10.1364/OPTICA.2.000850.

Energy efficiency of solar panels has to be improved significantly not only for the energy turnaround, but also for enhancing economic efficiency. Modules that are presently mounted on roofs convert just one fifth of the light into electricity, which means that about 80% of the solar energy are lost. The reasons of these high losses are manifold. Up to one tenth of the surface area of solar cells, for instance, is covered by so-called contact fingers that extract the current generated. At the locations of these contact fingers, light cannot reach the active area of the solar cell and efficiency of the cell decreases.

journal reference >>

Hydrogen for all seasons

Foto: Smileus /

(September 30, 2015)  LMU chemists have developed novel porous materials called “covalent organic frameworks”, which provide a basis for the design of polymeric photocatalysts with tunable physical, chemical and electronic properties.

Chemical systems that are capable of generating hydrogen gas by light-activated scission of water molecules (often termed artificial photosynthesis) represent a promising technology for the efficient storage of solar energy. However, the systems that have been developed so far suffer from various drawbacks, and intensive efforts are underway to discover alternative procedures that are both more practical and efficacious. Chemists led by Professor Bettina Lotsch, who has dual appointments in the Department of Chemistry at LMU and the Max Planck Institute for Solid State Research in Stuttgart now introduce a new class of porous organic materials that can be used as the basis for molecularly tunable photocatalysts for light-driven production of hydrogen gas. The researchers report their findings in the new issue of the online journal Nature Communications.

Lotsch and her colleagues are interested in the properties and practical applications of so-called covalent organic frameworks. These materials are composed of layers of regular two-dimensional molecular networks synthesized from simple organic precursors, and they exhibit a number of features that facilitate photocatalytic processes. “They form crystalline and porous semiconductors, whose chemical properties can be precisely tuned for a given application,” as Bettina Lotsch explains. They are already under investigation as possible matrices for the storage of gases and for applications in sensor technology, and also have considerable potential in the field of optoelectronics.

journal reference >>

UD professors say nation has fallen behind on offshore wind power

UD professors report in the Proceedings of the National Academy of Science
that the U.S. has fallen behind on offshore wind power.

(September 30, 2015)  University of Delaware faculty from the College of Earth, Ocean, and Environment (CEOE), the College of Engineering and the Alfred Lerner School of Business and Economics say that the U.S. has fallen behind in offshore wind power.

The UD professors, who are all affiliated with UD’s Center for Carbon Free Power Integration (CCPI), reported their findings in an invited paper that appeared this week in the prestigious journal Proceedings of the National Academy of Sciences.

Titled “The Time Has Come for Offshore Wind Power in the U.S.,” the paper asserts that while offshore wind turbines have been successfully deployed in Europe since 1991, the U.S. is further from commercial-scale offshore wind deployment today than it was in 2005.

“As we celebrate the 10-year anniversary of the U.S. Energy Policy Act of 2005, it is disheartening to see that while land-based wind and solar have reached new heights, U.S. offshore wind has remained a missed opportunity,” says the paper’s lead author, Jeremy Firestone, who is a professor in CEOE’s School of Marine Science and Policy and directs CCPI.

journal reference  >>

Are American Schools Making Inequality Worse?

(September 30, 2015)  The answer appears to be yes. Schooling plays a surprisingly large role in short-changing the nation’s most economically disadvantaged students of critical math skills, according to a study published today in Educational Researcher, a peer-reviewed journal of the American Educational Research Association.

Findings from the study indicate that unequal access to rigorous mathematics content is widening the gap in performance on a prominent international math literacy test between low- and high-income students, not only in the United States but in countries worldwide.

Using data from the 2012 Programme for International Student Assessment (PISA), conducted by the Paris-based Organisation for Economic Co-operation and Development (OECD), researchers from Michigan State University and OECD confirmed not only that low-income students are more likely to be exposed to weaker math content in schools, but also that a substantial share of the gap in math performance between economically advantaged and disadvantaged students is related to those curricular inequalities.

The authors—William H. Schmidt, Nathan Burroughs, and Richard Houang, all of Michigan State University, and Pablo Zoido, of OECD—found that in almost every one of the 62 countries examined, including the United States, a significant amount was added to the social class-related performance gap because of what students studied in schools. The 2012 PISA was the first international study to include student-level indicators of exposure to math content. The authors relied on data from more than 300,000 students, who ranged in age from 15 years and 3 months to 16 years and 2 months.

“Our findings support previous research by showing that affluent students are consistently provided with greater opportunity to learn more rigorous content, and that students who are exposed to higher-level math have a better ability to apply it to addressing real-world situations of contemporary adult life, such as calculating interest, discounts, and estimating the required amount of carpeting for a room,” said Schmidt, a University Distinguished Professor of Statistics and Education at Michigan State University. “But now we know just how important content inequality is in contributing to performance gaps between privileged and underprivileged students.”

image (read also) >>

Surface of the oceans affects climate more than thought

Illumination d'eau de mer synthétique, permettant l'étude de la photochimie
à l'interface air/mer  © Ircelyon

first detected abiotic source of isoprene

(September 30, 2015)  Lyon/ Leipzig. The oceans seem to produce significantly more isoprene, and consequently affect stronger the climate than previously thought. This emerges from a study by the Institute of Catalysis and Environment in Lyon (IRCELYON, CNRS / University Lyon 1) and the Leibniz Institute for Tropospheric Research (TROPOS), which had studied samples of the surface film in the laboratory. The results underline the global significance of the chemical processes at the border between ocean and atmosphere, write the researchers in the journal Environmental Science & Technology.

Isoprene is a gas that is formed by both the vegetation and the oceans. It is very important for the climate because this gas can form particles that can become clouds and then later affect temperature and precipitation. Previously it was assumed that isoprene is primarily caused by biological processes from plankton in the sea water. The atmospheric chemists from France and Germany, however, could now show that isoprene could also be formed without biological sources in surface film of the oceans by sunlight and so explain the large discrepancy between field measurements and models. The new identified photochemical reaction is therefore important to improve the climate models.

The oceans not only take up heat and carbon dioxide from the atmosphere, they are also sources of various gaseous compounds, thereby affecting the global climate. A key role is played by the so-called surface microlayer (SML),  especially at low wind speed. In these few micrometers thin layer different organic substances such as dissolved organic matter, fat and amino acids, proteins, lipids are accumulating as well as trace metals, dust and microorganisms.

For the now published study, the research team took samples from the Norther Atlantic Ocean. The  surface film was collected in the Raunefjord near Bergen in Norway. For this purpose, a glass plate is immersed in water and then again carefully pulled from the water. The 200 micron thin film sticks to the glass and is then scraped off with a wiper. The sample thus obtained is analyzed in the laboratory later. At the Institute of Catalysis and Environment in Lyon (IRCELYON), which belongs to the French research organization CNRS and the University of Lyon 1, the team investigated its photochemical properties during which collected samples were irradiated with light and the gases were analyzed:  it became clear that isoprene was produced in magtnetudes that were previously attributed solely to plankton. "We were able for the first time trace back the production of this important aerosol precursor  to abiotic sources, so far  global calculations consider only biological sources," explains Dr. Christian George from IRCELYON.

journal reference (Nature) >>

September 29, 2015


New prosthesis aims to help people living with memory loss

(September 29, 2015)  Researchers at USC and Wake Forest Baptist Medical Center have developed a brain prosthesis that is designed to help individuals suffering from memory loss.

The prosthesis, which includes a small array of electrodes implanted into the brain, has performed well in laboratory testing in animals and is currently being evaluated in human patients.

Designed originally at USC and tested at Wake Forest Baptist, the device builds on decades of research by Ted Berger and relies on a new algorithm created by Dong Song, both of the USC Viterbi School of Engineering. The development also builds on more than a decade of collaboration with Sam Deadwyler and Robert Hampson of the Department of Physiology & Pharmacology of Wake Forest Baptist who have collected the neural data used to construct the models and algorithms.

When your brain receives the sensory input, it creates a memory in the form of a complex electrical signal that travels through multiple regions of the hippocampus, the memory center of the brain. At each region, the signal is re-encoded until it reaches the final region as a wholly different signal that is sent off for long-term storage.

If there’s damage at any region that prevents this translation, then there is the possibility that long-term memory will not be formed. That’s why an individual with hippocampal damage (for example, due to Alzheimer’s disease) can recall events from a long time ago – things that were already translated into long-term memories before the brain damage occurred – but have difficulty forming new long-term memories.

Song and Berger found a way to accurately mimic how a memory is translated from short-term memory into long-term memory, using data obtained by Deadwyler and Hampson, first from animals, and then from humans. Their prosthesis is designed to bypass a damaged hippocampal section and provide the next region with the correctly translated memory.

That’s despite the fact that there is currently no way of “reading” a memory just by looking at its electrical signal.

“It’s like being able to translate from Spanish to French without being able to understand either language,” Berger said.

read entire press  release >>

Pirouetting in the spotlight

Bild: Artenauta /

(September 29, 2015)  Molecular motors are synthetic chemical compounds that can convert externally supplied energy into mechanical motion. Such molecules, which are specifically designed to execute directional movements in response to a specific stimulus, are an essential precondition for the construction of useful nanomachines. Among the most promising types of molecular ‘engine blocks’ are substances whose three-dimensional conformation can be altered by exposure to light. “However, all the light-activated molecular motors described so far utilize UV light as a power source. But this severely restricts their potential range of application, as its high-energy photons may have deleterious effects on the nanomachinery as a whole,” explains Dr. Henry Dube, who is at LMU’s Department of Chemistry. Dube and his colleagues have now found a way around this obstacle: They have developed a novel class of molecular rotor that can be driven by visible light – which is less energetic than UV radiation and therefore less likely to compromise the operation of more complex systems. The researchers describe the compound and its properties in a paper published in Nature Communications.

The basis of the newly developed molecular motor is the molecule hemithioindigo. Hemithioindigo is a photoswitch, which is made of two organic molecules, which are connected by a carbon double bond. Exposure to light alters the structure of hemithioindigo, causing it to rotate about the central double bond. In contrast to the light-activated motors previously described, rotation of the hemithioindigo-based motor requires the less energetic visible light – and it rotates extremely fast: The researchers demonstrated that the molecule rotates – unidirectionally – about 1000 times per second at room temperature. “We ourselves were surprised that the motor works so well, for it is known that many molecular motors do not steadily rotate in one direction, but also revolve in the opposite sense to some degree,” says Dube. “Given the complexity involved in the design of such motor molecules, it is really astonishing to that we gained complete control over the direction of rotation at the first attempt.”

read entire press  release >>

Hopes of improved brain implants

What looks like a bed of nails are actually nanowires. Each outgrowing thread
has a diameter of 80 nanometres (billionths of a metre). The green things
climbing on the nanowires are neurons.

(September 29, 2015)  Neurons thrive and grow in a new type of nanowire material developed by researchers in Nanophysics and Ophthalmology at Lund University in Sweden. In time, the results might improve both neural and retinal implants, and reduce the risk of them losing their effectiveness over time, which is currently a problem.
By implanting electrodes in the brain tissue one can stimulate or capture signals from different areas of the brain. These types of brain implants, or neuro-prostheses as they are sometimes called, are used to treat Parkinson’s disease and other neurological diseases.

They are currently being tested in other areas, such as depression, severe cases of autism, obsessive-compulsive disorders and paralysis. Another research track is to determine whether retinal implants are able to replace light-sensitive cells that die in cases of Retinitis Pigmentosa and other eye diseases.

However, there are severe drawbacks associated with today’s implants. One problem is that the body interprets the implants as foreign objects, resulting in an encapsulation of the electrode, which in turn leads to loss of signal.

“Our nanowire structure prevents the cells that usually encapsulate the electrodes – glial cells – from doing so”, says Christelle Prinz, researcher in Nanophysics at Lund University in Sweden, who developed this technique together with Maria Thereza Perez, a researcher in Ophthalmology.

“I was very pleasantly surprised by these results. In previous in-vitro experiments, the glial cells usually attach strongly to the electrodes”, she says.

To avoid this, the researchers have developed a small substrate where regions of super thin nanowires are combined with flat regions. While neurons grow and extend processes on the nanowires, the glial cells primarily occupy the flat regions in between.

read entire press  release >>

Wearable Electronic Health Patches May Now Be Cheaper and Easier to Make

Assitant professor Nanshu Lu and her team have developed a faster, inexpensive method
for making epidermal electronics. Cockrell School of Engineering

(September 29, 2015)  A team of researchers in the Cockrell School of Engineering at The University of Texas at Austin has invented a method for producing inexpensive and high-performing wearable patches that can continuously monitor the body’s vital signs for human health and performance tracking, potentially outperforming traditional monitoring tools such as cardiac event monitors.

The researchers published a paper on their patent-pending process in Advanced Materials on Sept. 23.

Led by Assistant Professor Nanshu Lu, the team’s manufacturing method aims to construct disposable tattoo-like health monitoring patches for the mass production of epidermal electronics, a popular technology that Lu helped develop in 2011.

The team’s breakthrough is a repeatable “cut-and-paste” method that cuts manufacturing time from several days to only 20 minutes. The researchers believe their new method is compatible with roll-to-roll manufacturing — an existing method for creating devices in bulk using a roll of flexible plastic and a processing machine.

Reliable, ultrathin wearable electronic devices that stick to the skin like a temporary tattoo are a relatively new innovation. These devices have the ability to pick up and transmit the human body’s vital signals, tracking heart rate, hydration level, muscle movement, temperature and brain activity.

Although it is a promising invention, a lengthy, tedious and costly production process has until now hampered these wearables’ potential.

read entire press  release >>

Broadleaf trees show reduced sensitivity to global warming

The international researchers investigated the change in the sensitivity of leaf unfolding
to climate warming using observations for dominant European tree species like this beech.
(Photo: Stefanie Ederer)

The response of leaf unfolding phenology to climate warming has significantly reduced

(September 29, 2015)  The sensitivity of leaf unfolding phenology to climate warming has significantly declined since 1980s, according to a study recently published in the journal Nature by an international collaboration of scientists. Earlier spring leaf unfolding is a frequently observed response of plants to climate warming. Many deciduous tree species require cold temperatures, in other words ‘chilling’, for dormancy release, and the warming-related reductions in chilling may counteract the advance of leaf unfolding in response to warming. Empirical evidence for this, however, was very limited.

To check whether warm winters have already attenuated the advance in spring phenology, an international team of researchers from China, Belgium, France, Spain, Switzerland and Germany investigated the change in the sensitivity of leaf unfolding to climate warming using long-term observations for seven dominant European tree species at 1245 sites in Central Europe.

Their analyses show that leaf unfolding occurred, on average, four days earlier per degree Celcius increase in spring temperature between 1980 and 1994, whereas this advance dropped to 2.3 days per degree between 1999 and 2013, a decrease of over 40 percent. “This lower sensitivity of trees to climate change likely reflects the reduced cold during winter that delays dormancy release. However, we could not fully exclude photoperiod and/or insolation as co-controlling mechanisms. These two factors may also become limiting when leaf unfolding dates occur too early in spring” said Yongshuo H. Fu, the first author of this study.

read entire press  release >>

Biomimetic dental prosthesis

(September 29, 2015)  ETH material researchers are developing a procedure that allows them to mimic the complex fine structure of biological composite materials, such as teeth or seashells. They can thus create synthetic materials that are as hard and tough as their natural counterparts.

There are few tougher, more durable structures in nature than teeth or seashells. The secret of these materials lies in their unique fine structure: they are composed of different layers in which numerous micro-platelets are joined together, aligned in identical orientation in each layer.

Although methods exist that allow material scientists to imitate nacre, it was a challenge to create a material that imitates the entire seashell, with comparable properties and structural complexity.

Now a group of researchers led by André Studart, Professor of Complex Materials, has developed a new procedure that mimics the natural model almost perfectly. The scientists were able to produce a tough, multi-layered material based on the construction principle of teeth or seashells. The ETH researchers managed, for the first time, to re-create in a single complex piece the multiple layers of micro-platelets with identical orientation in each layer.

It is a procedure the ETH researchers call magnetically assisted slip casting (MASC). “The wonderful thing about our new procedure is that it builds on a 100-year-old technique and combines it with modern material research,” says Studart’s doctoral student Tobias Niebel, co-author of a study just published in the specialist journal Nature Materials.

journal reference >>

First Optical Rectenna – Combined Rectifier and Antenna – Converts Light to DC Current

Optical rectenna schematic
This schematic shows the components of the optical rectenna developed at the
Georgia Institute of Technology. (Credit: Thomas Bougher, Georgia Tech)

(September 29, 2015)  Using nanometer-scale components, researchers have demonstrated the first optical rectenna, a device that combines the functions of an antenna and a rectifier diode to convert light directly into DC current.

Based on multiwall carbon nanotubes and tiny rectifiers fabricated onto them, the optical rectennas could provide a new technology for photodetectors that would operate without the need for cooling, energy harvesters that would convert waste heat to electricity – and ultimately for a new way to efficiently capture solar energy.

In the new devices, developed by engineers at the Georgia Institute of Technology, the carbon nanotubes act as antennas to capture light from the sun or other sources. As the waves of light hit the nanotube antennas, they create an oscillating charge that moves through rectifier devices attached to them. The rectifiers switch on and off at record high petahertz speeds, creating a small direct current.

Billions of rectennas in an array can produce significant current, though the efficiency of the devices demonstrated so far remains below one percent. The researchers hope to boost that output through optimization techniques, and believe that a rectenna with commercial potential may be available within a year.

Using nanometer-scale components, researchers have demonstrated the first optical rectenna,
a device that combines the functions of an antenna and a rectifier diode
to convert light directly into DC current.

“We could ultimately make solar cells that are twice as efficient at a cost that is ten times lower, and that is to me an opportunity to change the world in a very big way” said Baratunde Cola, an associate professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech. “As a robust, high-temperature detector, these rectennas could be a completely disruptive technology if we can get to one percent efficiency. If we can get to higher efficiencies, we could apply it to energy conversion technologies and solar energy capture.”

The research, supported by the Defense Advanced Research Projects Agency (DARPA), the Space and Naval Warfare (SPAWAR) Systems Center and the Army Research Office (ARO), was reported September 28 in the journal Nature Nanotechnology.

journal reference >>

New Processes in Modern ReRAM Memory Cells Decoded

Formation of metallic Tantalum (Ta) filament within Ta/TaO(x)/Pt ReRAM memory cell.
Positively charged Ta(5+)-ions and oxygen vacancies (V(O)) contribute to the process.
Copyright: Forschungszentrum Jülich / RWTH Aachen / Pössinger

(September 29, 2015)  Resistive memory cells or ReRAMs for short are deemed to be the new super information-storage solution of the future. At present, two basic concepts are being pursued, which, up to now, were associated with different types of active ions. But this is not quite correct, as Jülich researchers working together with their Korean, Japanese and American colleagues were surprised to discover. In valence change memory (VCM) cells, not only are negatively charged oxygen ions active, but – akin to electrochemical metallization memory (ECM) cells – so too are positively charged metal ions. The effect enables switching characteristics to be modified as required and makes it possible to move back and forth from one concept to the other, as reported by the researchers in the journals Nature Nanotechnology and Advanced Materials.

ReRAM cells have a unique characteristic: their electrical resistance can be altered by applying an electric voltage. The cells behave like a magnetic material that can be magnetized and demagnetized again. In other words, they have an ON and an OFF state. This enables digital information to be stored, i.e. information that distinguishes between "1" and "0". The most important advantages of ReRAMs are that they can be switched rapidly, consume little energy, and maintain their state even after long periods of time with no external voltage.

A look into the Oxide Cluster at Forschungszentrum Jülich in which resistive cells
and other layers of material are produced and examined in an ultrahigh vacuum.
Copyright: Forschungszentrum Jülich

The memristive behaviour of ReRAMs relay on mobile ions. These ions move in a similar manner to in a battery, flowing back and forth between two electrodes in a metal oxide layer no more than a few nanometres thick. For a long time, researchers believed that VCMs and ECMs functioned very differently. In ECMs, the ON and OFF states are achieved when metal ions move and form whisker-like filaments. This happens when an electric voltage is applied, causing such filaments to grow between the two electrodes of the cell. The cell is practically short-circuited and the resistance decreases abruptly. When the process is carefully controlled, information can be stored. The switching behaviour of VCMs, in contrast, were primarily associated with the displacement of oxygen ions. Contrary to metal ions, they are negatively charged. When a voltage is applied, the ions move out of an oxygen-containing metal compound. The material abruptly becomes more conductive. In this case as well, the process needs to be more carefully controlled.

read entire press  release >>

Breakthroughs need in-depth knowledge, not just cross-collaboration, study shows

(September 29, 2015)  Most high-impact innovation happens when knowledge and people from different fields are brought together to create something new, previous research has found.

But the latest findings from the University of Toronto's Rotman School of Management show that truly new, paradigm-busting ideas with long-term potential need profound knowledge in a narrow domain.  Organizations that ignore that in favour of recombining what's already known will miss out on the greatest potential breakthroughs.

Recombining existing knowledge "is only one piece of the puzzle," says Sarah Kaplan, a Rotman professor of strategic management who has co-written a study paper on the subject with Keyvan Vakili, an assistant professor at the London Business School, who is a graduate of the Rotman PhD program.

Previous research has measured levels of innovation by looking at how frequently a patent is cited in subsequent patent registrations. That measures the idea's economic usefulness, but not how truly new the idea is, say the current study's researchers.

Instead, they looked for cases where new language and terms were brought into patent Information, signalling the introduction of completely new ideas. Creating a novelty of their own, they adapted a computer science text analysis technique called "topic modelling," for their analysis. They applied it to patents over a 20-year period in a branch of nanotechnology called “buckminsterfullerenes”.

watch video >>

September 28, 2015

A light Touch: Embedded optical sensors could make robotic hands more dexterous

Carnegie Mellon Creates Sensor-rich Robotic Hand and New Stretchable Sensor

(September 28, 2015)  Optical sensors may be uniquely suited for use in robotic hands, according to Carnegie Mellon University researchers who have developed a three-fingered soft robotic hand with multiple embedded fiber optic sensors. They also have created a new type of stretchable optical sensor.
By using fiber optics, the researchers were able to embed 14 strain sensors into each of the fingers in the robotic hand, giving it the ability to determine where its fingertips are in contact and to detect forces of less than a tenth of a newton. The new stretchable optical sensing material, not incorporated in this version of the hand, potentially could be used in a soft robotic skin to provide even more feedback.
“If you want robots to work autonomously and to react safely to unexpected forces in everyday environments, you need robotic hands that have more sensors than is typical today,” said Yong-Lae Park, assistant professor of robotics. “Human skin contains thousands of tactile sensory units only in the fingertip and a spider has hundreds of mechanoreceptors on each leg, but even a state-of-the-art humanoid such as NASA’s Robonaut has only 42 sensors in its hand and wrist.”

The new stretchable optical sensor coud be used in
a soft rotobic skin to detect contact and measure force.

Adding conventional pressure or force sensors is problematic because wiring can be complicated, prone to breaking and susceptible to interference from electric motors and other electromagnetic devices. But a single optical fiber can contain several sensors; all of the sensors in each of the fingers of the CMU hand are connected with four fibers, although, theoretically, a single fiber could do the job, Park said. And the optical sensors are impervious to electromagnetic interference.

The Carnegie Mellon researchers will discuss the robotic hand, developed together with researchers at Intelligent Fiber Optic Systems Corp., with support from NASA, Sept. 29 at the IEEE International Conference on Intelligent Robots and Systems, IROS 2015, in Hamburg, Germany. A report on the highly stretchable optical sensors will be presented Oct. 1 at the same conference.

read entire press  release >>

New Tech Automatically ‘Tunes’ Powered Prosthetics While Walking

(September 28, 2015)  When amputees receive powered prosthetic legs, the power of the prosthetic limbs needs to be tuned by a prosthetics expert so that a patient can move normally – but the prosthetic often needs repeated re-tuning. Biomedical engineering researchers at North Carolina State University and the University of North Carolina at Chapel Hill have now developed software that allows powered prosthetics to tune themselves automatically, making the devices more functionally useful and lowering the costs associated with powered prosthetic use.

“When a patient gets a powered prosthetic, it needs to be customized to account for each individual patient’s physical condition, because people are different in size and strength. And that tuning is done by a prosthetist,” says Helen Huang, lead author of a paper on the work and an associate professor in the biomedical engineering program at NC State and UNC-Chapel Hill. “In addition, people are dynamic – a patient’s physical condition may change as he or she becomes accustomed to a prosthetic leg, for example, or they may gain weight. These changes mean the prosthetic needs to be re-tuned, and working with a prosthetist takes time and money.”

To address this problem, the researchers developed an algorithm that can be incorporated into the software of any powered prosthesis to automatically tune the amount of power a prosthetic limb needs in order for a patient to walk comfortably. The algorithm would not only make it easier for patients to walk while reducing prosthetist-related costs, but would also allow a prosthesis to adjust to changing conditions. Video of the technology in action can be seen here.

“For example, the algorithm could provide more power to a prosthesis when a patient carries a heavy suitcase through an airport,” Huang says.

watch video >>

Opening up product design to the consumer through 3D printing

Speaker that grows in a piece of furniture, the shape is generated
by an algorithm to suit one’s physical space.

(September 28, 2015)  Through the use of 3D printing, product designers can enable the consumer to design their own everyday products thereby creating more meaningful products for people and more value for companies. These are some of the conclusions Guido Hermans draws in his dissertation, which he defends at Umeå Institute of Design on Tuesday 6 October.

“The two questions that I have focused on are: How will the roles of the professional designer and the layperson change when the latter engages in the design of personal products? And, how can designers develop digital-physical toolkits for the layperson to collaboratively create value and meaning?” says Guido Hermans.

Within product design there has traditionally been a gap between production and consumption, with distinct roles for the professional designer, who engages in production, and the consumer, who engages in consumption. However, this clear distinction has been blurred recently and the consumer, or layperson, is no longer involved only in consumption, but also in production.

In his research, Guido Hermans has investigated a way to open up design to the consumer and how to give this group an active role in the design of everyday products.

“This role change implies a shift for the professional designer from knowing what a future user would like to have towards knowing what a layperson would like to design, which is for most designers an unfamiliar way of thinking,” says Guido Hermans.

read entire press  release >>

Goods manufactured in China not good for the environment, study finds

A coal-fired power station in rural Zhejiang Province, China. Steven J. Davis (2015)

UCI, other researchers link products made there with higher CO2 emissions

(September 28, 2015)  In a study published today in the journal Nature Climate Change, scientists from three universities show that products made in China are associated with significantly higher carbon dioxide emissions than the same products made elsewhere.

“The amazing increase in Chinese manufacturing over the past 15 years has driven the world economy to new heights and supplied consumers in developed countries with tremendous quantities of lower-cost goods,” said co-author Steven J. Davis, an assistant professor of Earth system science at the University of California, Irvine. “But all of this has come at substantial cost to the environment.”

The researchers, also from Harvard University and the University of Maryland, attribute China’s high emissions intensity – the quantity of CO2 emitted per dollar of goods produced – to the nation’s antiquated manufacturing processes and reliance on coal.

“The CO2 emissions related to China’s exports are large not just because they export a lot of stuff or because they specialize in energy-demanding industries, but because their manufacturing technologies are less advanced and they rely primarily on coal for energy,” said co-author Klaus Hubacek, a University of Maryland professor of geographical sciences.

In an earlier study, UCI’s Davis showed that developed countries were outsourcing both jobs and the problem of industrial pollution by having products manufactured in low-wage economies like China’s. This new work goes a step further to demonstrate that consumption of Chinese-made goods by consumers in advanced economies is potentially accelerating global climate change, a problem without national borders.

read entire press  release >>

Archimedes Table

(September 28, 2015)  Patented modular table. Archimedes offers two different styles in high position and low position using an ingenious deployment system.

Able to change from one state to another in a split second and with simplified handling, it impresses with the design of its structure, noble materials as much as by its ability to respond to our evolving lifestyle.

souırce >>

A natural light switch

Color-corrected photograph of bacteria "spelling" B12, when the vitamin-B12-dependent
photoreceptor protein, CarH, senses light.
Image: Carmen Polanco and Montserrat Elías-Arnanz/University of Murcia (edited by MIT News)

MIT scientists identify and map the protein behind a light-sensing mechanism.

(September 28, 2015)  MIT scientists, working with colleagues in Spain, have discovered and mapped a light-sensing protein that uses vitamin B12 to perform key functions, including gene regulation.

The result, derived from studying proteins from the bacterium Thermus thermophilus, involves at least two findings of broad interest. First, it expands our knowledge of the biological role of vitamin B12, which was already understood to help convert fat into energy, and to be involved in brain formation, but has now been identified as a key part of photoreceptor proteins — the structures that allow organisms to sense and respond to light.

Second, the research describes a new mode of gene regulation, in which the light-sensing proteins play a key role. In so doing, the scientists observe, the bacteria have repurposed existing protein structures that use vitamin B12, and put them to work in new ways.

“Nature borrowed not just the vitamin, but really the whole enzyme unit, and modified it … and made it a light sensor,” says Catherine Drennan, a professor of chemistry and biology at MIT.

The findings are detailed this week in the journal Nature. The paper describes the photoreceptors in three different states: in the dark, bound to DNA, and after being exposed to light.
“It’s wonderful that we’ve been able to get all the series of structures, to understand how it works at each stage,” Drennan says.

The photoreceptor CarH (red) breaks apart and falls off DNA upon light exposure.
Image: David Born, Marco Jost, and Catherine Drennan/MIT (edited by MIT News)

The paper has nine co-authors, including Drennan; graduate students Percival Yang-Ting Chen, Marco Jost, and Gyunghoon Kang of MIT; Jesus Fernandez-Zapata and S. Padmanabhan of the Institute of Physical Chemistry Rocasolano, in Madrid; and Monserrat Elias-Arnanz, Juan Manuel Ortiz-Guerreo, and Maria Carmen Polanco, of the University of Murcia, in Murcia, Spain.

The researchers used a combination of X-ray crystallography techniques and in-vitro analysis to study the bacteria. Drennan, who has studied enzymes that employ vitamin B12 since she was a graduate student, emphasizes that key elements of the research were performed by all the co-authors.

read entire press  release >>