SLAC’s Ultrafast ‘Electron Camera’ Visualizes Ripples in 2-D Material

Researchers have used SLAC’s experiment for ultrafast electron diffraction (UED),

one of the world’s fastest “electron cameras,” to take snapshots of a three-atom-thick

layer of a promising material as it wrinkles in response to a laser pulse.

Understanding these dynamic ripples could provide crucial clues for the

development of next-generation solar cells, electronics and catalysts.

(SLAC National Accelerator Laboratory)

Understanding Motions of Thin Layers May Help Design Solar Cells, Electronics and Catalysts of the Future

(September 10, 2015)  New research led by scientists from the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University shows how individual atoms move in trillionths of a second to form wrinkles on a three-atom-thick material. Revealed by a brand new “electron camera,” one of the world’s speediest, this unprecedented level of detail could guide researchers in the development of efficient solar cells, fast and flexible electronics and high-performance chemical catalysts.

The breakthrough, accepted for publication Aug. 31 in Nano Letters, could take materials science to a whole new level. It was made possible with SLAC’s instrument for ultrafast electron diffraction (UED), which uses energetic electrons to take snapshots of atoms and molecules on timescales as fast as 100 quadrillionths of a second.

“This is the first published scientific result with our new instrument,” said scientist Xijie Wang, SLAC’s UED team lead. “It showcases the method’s outstanding combination of atomic resolution, speed and sensitivity.”

SLAC Director Chi-Chang Kao said, “Together with complementary data from SLAC’s X-ray laser Linac Coherent Light Source, UED creates unprecedented opportunities for ultrafast science in a broad range of disciplines, from materials science to chemistry to the biosciences.” LCLS is a DOE Office of Science User Facility.

This animation explains how researchers use high-energy electrons at SLAC to study

faster-than-ever motions of atoms and molecules relevant to important materials

properties and chemical processes.

Extraordinary Material Properties in Two Dimensions

Monolayers, or 2-D materials, contain just a single layer of molecules. In this form they can take on new and exciting properties such as superior mechanical strength and an extraordinary ability to conduct electricity and heat. But how do these monolayers acquire their unique characteristics? Until now, researchers only had a limited view of the underlying mechanisms.

Illustrations (each showing a top and two side views) of a single layer of molybdenum

disulfide (atoms shown as spheres). Top left: In a hypothetical world without motions,

the “ideal” monolayer would be flat. Top right: In reality, the monolayer is wrinkled as

shown in this room-temperature simulation. Bottom: If a laser pulse heats the monolayer up,

it sends ripples through the layer. These wrinkles, which researchers have now observed

for the first time, have large amplitudes and develop on ultrafast timescales.

(SLAC National Accelerator Laboratory)

“The functionality of 2-D materials critically depends on how their atoms move,” said SLAC and Stanford researcher Aaron Lindenberg, who led the research team. “However, no one has ever been able to study these motions on the atomic level and in real time before. Our results are an important step toward engineering next-generation devices from single-layer materials.” The research team looked at molybdenum disulfide, or MoS2, which is widely used as a lubricant but takes on a number of interesting behaviors when in single-layer form – more than 150,000 times thinner than a human hair.

For example, the monolayer form is normally an insulator, but when stretched, it can become electrically conductive. This switching behavior could be used in thin, flexible electronics and to encode information in data storage devices. Thin films of MoS2 are also under study as possible catalysts that facilitate chemical reactions. In addition, they capture light very efficiently and could be used in future solar cells.

Visualization of laser-induced motions of atoms (black and yellow spheres) in a molybdenum

disulfide monolayer: The laser pulse creates wrinkles with large amplitudes – more than

15 percent of the layer’s thickness – that develop in a trillionth of a second.

(K.-A. Duerloo/Stanford)

Because of this strong interaction with light, researchers also think they may be able to manipulate the material’s properties with light pulses.

“To engineer future devices, control them with light and create new properties through systematic modifications, we first need to understand the structural transformations of monolayers on the atomic level,” said Stanford researcher Ehren Mannebach, the study’s lead author.

Electron Camera Reveals Ultrafast Motions

Previous analyses showed that single layers of molybdenum disulfide have a wrinkled surface. However, these studies only provided a static picture. The new study reveals for the first time how surface ripples form and evolve in response to laser light.

To study ultrafast atomic motions in a single layer of molybdenum disulfide,

researchers followed a pump-probe approach: They excited motions with a laser pulse

(pump pulse, red) and probed the laser-induced structural changes with a subsequent

electron pulse (probe pulse, blue). The electrons of the probe pulse scatter off the

monolayer’s atoms (blue and yellow spheres) and form a scattering pattern on the detector

– a signal the team used to determine the monolayer structure. By recording patterns at

different time delays between the pump and probe pulses, the scientists were able to

determine how the atomic structure of the molybdenum disulfide film changed over time.

(SLAC National Accelerator Laboratory)

Researchers at SLAC placed their monolayer samples, which were prepared by Linyou Cao’s group at North Carolina State University, into a beam of very energetic electrons. The electrons, which come bundled in ultrashort pulses, scatter off the sample’s atoms and produce a signal on a detector that scientists use to determine where atoms are located in the monolayer. This technique is called ultrafast electron diffraction.

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UT RESEARCHERS GIVE NANOSHEETS LOCAL MAGNETIC PROPERTIES

Caption: EBSD image showing the local structure of a thin film. The left half of these

images shows the preferred direction of the LaSrMnO3-film perpendicular to the

growth direction, while the right half shows the directions in the plane with the contours

of the individual nanosheets clearly visible. The distance between two lines in the

pattern is a few micrometers.

(September 10, 2015)  Two-dimensional crystals are very suitable for creating high-quality magnetic thin films. This appears from two recent publications written by scientists from the University of Twente's MESA+ research institute. The researchers show that by growing the magnetic layers on various 2D crystals, better known as nanosheets, you can control the preferred direction of the magnetism very locally. In an article published in Advanced Functional Materials, they present this method to create magnetic patterns on the micrometer scale. In Angewandte Chemie, they demonstrate that you can make the nanosheets in less than a minute, while the synthesis process had been known to be very slow. The magnetic films can be deployed for many different applications, such as new generations of smartphones.

With pulsed laser deposition (PLD) you can achieve controlled growth of thin layers of certain materials. Here, a material is heated rapidly with a powerful laser beam, so that it evaporates and a plasma is created. This spreads quickly in a vacuum chamber and is deposited on a substrate where it forms a thin layer. In this way you can control the thickness of the layer and you can form smooth and thin layers, often with special properties that are interesting for use in electronics and electro-mechanics, for example. For such applications, it is however essential that you can also make patterns in the layered materials. This is not easy, especially because the substrate needs to be heated to temperatures above 500° C during the PLD process. Many of the existing methods are therefore not adapted to existing manufacturing methods for microstructures.

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Oxygen is not Definitive Evidence of Life on Habitable Extrasolar Planets

Figure. Photocatalytic Reaction of Titanium Oxide

Abiotic oxygen can be produced from water in the presence of titanium oxide and an

electron acceptor under UV light. Our report suggests that this photocatalytic reaction

can supply significant amount of abiotic oxygen on habitable extrasolar planets.

(September 10, 2015)  The Earth’s atmosphere contains oxygen because plants continuously produce it through photosynthesis. This abundant supply of oxygen allows life forms like animals to flourish. Therefore, oxygen had been thought to be an essential biomarker for life on extrasolar planets. But now, a research assistant professor Norio Narita of the Astrobiology Center of NINS, which was founded in April 2015, and an associate professor Shigeyuki Masaoka, of the Institute of Molecular Science of NINS, have presented a novel hypothesis that it could be possible for planets to have large quantities of abiotic (non-biologically produced) oxygen. This study is a good example of interdisciplinary studies that combine knowledge from different fields of science to promote astrobiology in the search for life on extrasolar planets. The study is published in Scientific Reports on Sep 10, 2015.

Until now, it had been thought that if a planet has oxygen, that must mean that some form of plants are producing it through photosynthesis. Therefore, it had been assumed that when searching for signs of life on habitable extrasolar planets, the presence of oxygen in the atmosphere could be considered a definitive biomarker. However, non-biological chemical reactions can also affect atmospheric compositions of extrasolar planets. Now, the research team led by Dr. Narita has shown that, abiotic oxygen produced by the photocatalytic reaction of titanium oxide, which is known to be abundant on the surfaces of terrestrial planets, meteorolites, and the Moon in the Solar System, cannot be discounted.

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New Species of Human Relative Discovered

A reconstruction of Homo naledi’s head by paleoartist John Gurche, who spent

some 700 hours recreating the head from bone scans. The find was announced

by the University of the Witwatersrand, the National Geographic Society and the

South African National Research Foundation and published in the journal eLife.

Photo by Mark Thiessen/National Geographic

(September 10, 2015)  An international research team, which includes NYU anthropologists Scott Williams and Myra Laird, has discovered a new species of a human relative. Homo naledi, uncovered in a cave outside of Johannesburg, South Africa, sheds light on the diversity of our genus and possibly its origin.

“This discovery is unprecedented in the sheer number of hominins collected from such a small area in the virtual absence of other animal remains,” says Williams, an assistant professor in NYU’s Department of Anthropology. “That makes this site unique. Moreover, the announcement describes only the tip of the iceberg of analyses that will come, and we hope that is also true of the cave itself and the material that it still holds.”

The team’s findings, which are published in two papers in the journal eLife, were announced by South Africa’s University of the Witwatersrand, the National Geographic Society, and the South African National Research Foundation.

The discovery also indicates that H. naledi intentionally deposited bodies of its dead in a remote cave chamber—behaviors previously thought limited to humans.

Lee Berger, a research professor in the Evolutionary Studies Institute at the University of the Witwatersrand and a National Geographic Explorer-in-Residence, led the expeditions that recovered the fossils—more than 1,500 bones belonging to at least 15 individuals.

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Squabbles at work may be due to office design

Conflict and tension appear to be generated by certain popular office design concepts,

namely combo- and flex-offices.

(September 10, 2015)  Your likelihood of squabbling with co-workers could be due to the design of your office, a new study suggests.

A recent survey of Swedish office workers shows that, particularly for women, the risk of conflict at work increases in so-called combi- and flex-offices. And what's worse, women are more bothered by noise in these types of office plans than men are.

The findings were published recently in the Journal of Environmental Psychology, by co-authors Christina Bodin Danielsson, a researcher at Stockholm's KTH Royal Institute of Technology School of Architecture & Built Environment and Stockholm University's Stress Research Institute; Töres Theorell from SU's Stress Research Institute; Lennart Bodin from Karolinska Institute; and Cornelia Wulff, from Mäldardalen University.

Increasingly popular combi- and flex-offices are activity-based designs that offer employees a choice of work environments for different activities. Flex-offices also mean no one has their own, individual workstation. Combi-offices, on the other hand, offer individual workspaces but are designed for team-based work. They're highly stressful, too, says Bodin Danielsson.

"In a combi-office, the fact that you work as a team could be a possible explanation for the environment's negative impact on conflicts, Bodin Danielsson says. "Group work itself shown to lead to conflicts."

Surprisingly perhaps, the study also found that significantly fewer conflicts arise in large open office plans, where 25 more people work. This was especially true for women, Bodin Danielsson says. "Men appear to be less sensitive to the influence of office type for workplace conflicts."

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Your stomach bacteria determines which diet is best for weight reduction

The computational algorithm allowed for calculation of micronutrient content in different foods,

and hereby it is possible to calculate how diet impacts the metabolism in the human gut microbiome.

In the study it was found that subjects with low gene counts (LGC), having a compressed gut

microbiota, respond better to dietary intervention than subjects with a high gene count (HGC),

due to differences in the metabolism of the gut microbiota in the two groups.

(September 10. 2015)  New research enables "tailored" diet advice – based on our personal gut microbiome – for persons who want to lose weight and reduce the risk of disease. Systems biologists at Chalmers University of Technology have for the first time successfully identified in detail how some of our most common intestinal bacteria interact during metabolism.

The researchers at Chalmers University of Technology have developed a mathematical calculation platform that makes it possible to predict how different patients will respond to a modified diet, depending on how their gut microbiome is composed.

Work has been conducted in cooperation in the context of the EU funded project Metacardis, coordinated by professor Karine Clement at Institute of Cardiometabolism and Nutrition (Ican, Pitié-Salpêtrière Hospital, Inserm/Sorbonne University) in Paris and also includes professor Fredrik Bäckhed at the University of Gothenburg.

"This method allows us to begin identifying each individual bacteria type's metabolism and thus get a handle on the basic mechanisms in human metabolism," says Jens Nielsen, professor of systems biology at Chalmers and head of the research team.

There can be up to 1,000 different types of bacteria and other microorganisms in the human digestive system, many of which take part in metabolism in one way or another. The composition of the human gut microbiome greatly varies between individuals, for reasons that are largely unknown. However, research over the past few years has shown that there is a connection between some diseases and the composition of the gut microbiome.

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Metal-eating microbes in African lake could solve mystery of the planet’s iron deposits

(September 10, 2015)  Tiny microbes like the ones in Kabuno Bay may have created some of the world’s largest ore deposits.

An isolated, iron-rich bay in the heart of East Africa is offering scientists a rare glimpse back into Earth’s primitive marine environment, and supports theories that tiny microbes created some of the world’s largest ore deposits billions of years ago.

According to University of British Columbia research published this week in Scientific Reports, 30 per cent of the microbes in the Democratic Republic of the Congo’s Kabuno Bay grow by a type of photosynthesis that oxidizes (rusts) iron rather than converting water into oxygen like plants and algae.

“Kabuno Bay is a time machine back to the Earth’s early history when iron-rich ocean chemistry prevailed,” said Marc Llirós of the University of Namur, first author of the paper.

“The bay is giving us real-world insight into how ancient varieties of photosynthesis may have supported Earth’s early life prior to the evolution of the oxygen producing photosynthesis that supports life today,” said UBC geomicrobiologist Sean Crowe, senior author of the study.

While iron-photosynthesizing bacteria were discovered in 1993, the new Scientific Reports study provides evidence that microorganisms could have been directly involved in depositing the Earth’s oldest iron formations.

Before 2.3 billion years ago, there was little oxygen in the atmosphere but plenty of dissolved iron and many organisms like bacteria derived energy by metabolizing the metal. Many researchers believe iron-metabolizing microbes might have turned plentiful dissolved iron into minerals, which then settled out of seawater and deposited along the ocean floor.

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Researchers shed light on potential shield from Alzheimer’s

Graduate and undergraduate students work the lab of Liqin Zhao, assistant professor

of pharmacology and toxicology at the School of Pharmacy. Image courtesy Liqin Zhao.

(September 10, 2015)  Today, more than 5.1 million Americans live with Alzheimer’s disease, a devastating type of dementia that plagues memory and thinking. That number is expected to triple in the coming decades. Moreover, according to a 2012 survey, Americans fear Alzheimer’s more than any other disease.

But studies looking into treatments for Alzheimer’s disease have been frustratingly disappointing.

“There is no cure for Alzheimer’s disease,” said Liqin Zhao, assistant professor of pharmacology and toxicology at the University of Kansas School of Pharmacy. “Five available Alzheimer’s disease drugs were all approved by FDA 10 years ago, and they provide only temporary symptomatic relief for an average of six to 12 months.”

Zhao said that over the last decade, more than 100 human trials aimed at Alzheimer’s disease treatment have been conducted with little success.

Now, she’s part of a KU team that has published a breakthrough investigation into human ApoE2, a seemingly protective “apolipoprotein” created by the ApoE gene — a gene associated with Alzheimer’s disease risk. The research appears in the Journal of Alzheimer’s Disease 48(2).

“Human ApoE is polymorphic and exists in three major alleles — ApoE2, ApoE3 and ApoE4,” Zhao said. “ApoE2 is a rare form and is considered neuroprotective. ApoE3 is the most common form and considered to play a neutral role in AD. ApoE4 is the greatest genetic risk factor for late-onset sporadic AD — ApoE4 occurs in only about 20 percent of the total population but accounts for approximately  50 percent of the Alzheimer’s disease population.”

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Science provides new way to peer into pores

The paths fluorescent particles take as they diffuse through a porous nanoscale

structure reveal the arrangement of the pores through a technique developed by

scientists at Rice University. (Credit: Landes Research Group/Rice University)

Rice University lab finds technique to characterize nanoscale spaces in porous materials 

(September 10, 2015)  Rice University scientists led a project to “see” and measure the space in porous materials, even if that space is too small or fragile for traditional microscopes.

The Rice lab of chemist Christy Landes invented a technique to characterize such nanoscale spaces, an important advance toward her group’s ongoing project to efficiently separate “proteins of interest” for drug manufacture. It should also benefit the analysis of porous materials of all kinds, like liquid crystals, hydrogels, polymers and even biological substances like cytosol, the compartmentalized fluids in cells.

The research with collaborators at the University of California, Los Angeles (UCLA) and Kansas State University appears in the American Chemical Society journal ACS Nano.

It’s easy to use a fluorescent chemical compound to tag, or “label,” a material and take a picture of it, Landes said. “But what if the thing you want a picture of is mostly nothing? That’s the problem we had to solve to understand what was going on in the separation material.”

The team aims to improve protein separation in a process called chromatography, in which solutions flow through porous material in a column. Because different materials travel at different speeds, the components separate and can be purified.

“We learned that in agarose, a porous material used to separate proteins, the clustering of charges is very important,” Landes said. While the protein project succeeded, “when we matched experimental data to our theory, there was something additional contributing to the separation that we couldn’t explain.”

The answer appeared to be with how charged particles like nanoscale ligands arranged themselves in the pores. “It was the only possible explanation,” Landes said. “So we needed a way to image the pores.”

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Pilot Study: Noninvasive Brain Stimulation Temporarily Improves Motor Symptoms in People with Parkinson’s Disease

A volunteer models the noninvasive, electrical stimulation device

used in this study. Reza Shadmehr, Johns Hopkins Medicine

FAST FACTS:

*  People with Parkinson’s disease are still capable of making quick, forceful movements even though most of their movements are slower and less intense than usual.

** Researchers measured the force that patients applied to their affected and less affected arms to achieve a combined target force in a specified direction.

*  They found that patients who received noninvasive brain stimulation split the force applied by their arms more evenly and improved motor symptoms in some patients.

(September 10, 2015)  People with Parkinson’s disease (PD) tend to slow down and decrease the intensity of their movements even though many retain the ability to move more quickly and forcefully. Now, in proof-of-concept experiments with “joysticks” that measure force, a team of Johns Hopkins scientists report evidence that the slowdown likely arises from the brain’s “cost/benefit analysis,” which gets skewed by the loss of dopamine in people with PD.

In addition, their study with a small group of 20 patients with PD demonstrated that stimulation of the cortex of the brain using external electrodes corrected some of the distortion and temporarily improved some patients’ motor symptoms. PD affects up to 1 million Americans.

“The loss of dopamine associated with Parkinson’s disease makes the effort required to move the affected side of the body seem greater, so the brain is less willing to use that arm to complete tasks,” says Reza Shadmehr, Ph.D., professor of biomedical engineering at the Johns Hopkins University School of Medicine. “Our study suggests that direct current stimulation can compensate somewhat for the loss of dopamine by decreasing the effort the brain has to put into getting its motor neurons to fire,” adds Shadmehr, the senior author of a report on the research published online in The Journal of Neuroscience on Sept. 2.

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A new factor in depression? Brain protein discovery could lead to better treatments

Study in humans & rats shows more physical changes in depressed brains

(September 9, 2015)  Low. Down. Less than normal. That’s what the word depression means, and what people with depression often feel like. But sometimes, depression can mean too much of something – as new research shows.

The discovery, about a protein called fibroblast growth factor 9 or FGF9, goes against previous findings that depressed brains often have less of key components than non-depressed brains.

In this case, people with major depression had 32 percent more of FGF9 in a key part of their brain than people without the condition. In rats, raising FGF9 levels artificially led to depression-like behavior changes, and repeated social stress caused brain FGF9 levels to rise.

Taken together, the findings provide more evidence that depression is a physical illness. If FGF9 or its effects prove to be a good target for drugs, the finding could eventually help lead to better medications for the mental health condition that affects millions of Americans.

FGF9’s role was discovered by a team from the University of Michigan Medical School and the Pritzker Neuropsychiatric Disorders Research Consortium, who report their results today in the Proceedings of the National Academy of Sciences. They made the discoveries through years of detailed comparisons of brain tissue donated by people with and without depression, and multiple studies in rats.

The green cells show where the researchers used an injected virus to block

production of FGF9 in rat brains -- and reduce anxiety-like behavior.

Because drugs that block excess production of something in the body generally cause fewer side effects than drugs aimed at increasing something, the team says their findings could hold promise for the development of a new class of antidepressants.

“Fixing depression is not easy, because it’s a disorder at the level of the circuits that connect brain cells, and many regions of the brain are involved,” says Elyse Aurbach, the neuroscience doctoral student who is the paper’s co-first author. “Still, this is the first time FGF9 has been identified as related to depression, and found to be active in a critical area of the brain for the disorder. We and others need to study it further to determine what is going on. It’s very exciting.”

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Researchers develop novel test which can tell how well a person is ageing

Image: Dreamstime

(September 8, 2015)  The findings, published today in Genome Biology, could help improve management of age-related disease by identifying people most at risk of diseases affected by age, as well as improve the way anti-ageing treatments are evaluated.

The seven-year collaborative study at King’s College London, Karolinska Institutet in Sweden and Duke University in the USA, used a process called RNA-profiling to measure and compare gene expression in thousands of human tissue samples. Rather than looking for genes associated with disease or extreme longevity, the Medical Research Council (MRC)-funded researchers discovered that the ‘activation’ of 150 genes in the blood, brain and muscle tissue were a hallmark of good health at 65 years of age. The researchers were then able to create a reproducible formula for ‘healthy ageing’, and use this to tell how well a person is ageing when compared to others born the same year.

The researchers found an extensive range in ‘biological age’ scores of people born at the same time indicating that a person’s biological age is separate and distinct to his or her chronological age.

Importantly, a low score was found to correlate with cognitive decline, implying that the molecular test could translate into a simple blood test to predict those most at risk of Alzheimer’s disease or other dementias and suitable for taking part in prevention trials.

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Nanoparticles — small but unique

A single gold plasmonic nanoantenna probes the hydrogen absorption in an adjacent

palladium nanocube. Illustration by Ella Marushchenko and Alex Tokarev.

(September 8, 2015)  Scientists at Chalmers University of Technology have developed a new way to study nanoparticles one at a time, and have discovered that individual particles that may seem identical in fact can have very different properties. The results, which may prove to be important when developing new materials or applications such as hydrogen sensors for fuel cell cars, will be published in Nature Materials.

— We were able to show that you gain deeper insights into the physics of how nanomaterials interact with molecules in their environment by looking at the individual nanoparticle as opposed to looking at many of them at the same time, which is what is usually done, says Associate Professor Christoph Langhammer, who led the project.

By applying a new experimental approach called plasmonic nanospectroscopy, the group studied hydrogen absorption into single palladium nanoparticles and found that particles with exactly the same shape and size may exhibit differences as great as 40 millibars in the pressure at which hydrogen is absorbed. The development of sensors that can detect hydrogen leaks in fuel cell powered cars is one example of where this new understanding could become valuable in the future.

— One main challenge when working on hydrogen sensors is to design materials whose response to hydrogen is as linear and reversible as possible. In that way, the gained fundamental understanding of the reasons underlying the differences between seemingly identical individual particles and how this makes the response irreversible in a certain hydrogen concentration range can be helpful, says Langhammer.

Others have looked at single nanoparticles one at a time, but the new approach introduced by the Chalmers team uses visible light with low intensity to study the particles. This means that the method is non-invasive and does not disturb the system it is investigating by, for example, heating it up.

— When studying individual nanoparticles you have to send some kind of probe to ask the particle ‘what are you doing?’. This usually means focusing a beam of high-energy electrons or photons or a mechanical probe onto a very tiny volume. You then quickly get very high energy densities, which might perturb the process you want to look at. This effect is minimized in our new approach, which is also compatible with ambient conditions, meaning that we can study nanoparticles one at a time in as close to a realistic environment as possible.

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Poison in Arctic and human cost of ‘clean’ energy

Photo by Prentiss H. Balcom

Postdoctoral fellow Amina Schartup, the paper’s first author, aboard the “What’s Happening” on Lake

Melville. In 2017, a dam will flood a large region upstream from an estuarine fjord called Lake Melville.

Hydroelectric energy may be more damaging to northern ecosystems than climate change

(September 8, 2015)  Colonial New Delhi had a cobra infestation. To get rid of it, the government offered bounties for dead cobras, inadvertently turning cobra breeding into a thriving business. When the government got wise and canceled the program, thousands of then worthless cobras were released into the city streets.

Today, the cobra effect means making a problem worse by attempting to solve it.

Arctic regions don’t have a poisonous snake problem; they have a poison problem.

The amount of methylmercury, a potent neurotoxin, is especially high in Arctic marine life but until recently, scientists haven’t been able to explain why. Now, research from the Harvard John A. Paulson School of Engineering and Applied Science (SEAS) and Harvard T.H. Chan School of Public Health suggests that high levels of methylmercury in Arctic life are a byproduct of global warming and the melting of sea-ice in Arctic and sub-Arctic regions.

View of Lake Melville from Rigolet, a Nunatsiavut community on the far eastern edge

of the lake. Photo by Prentiss H. Balcom

To mitigate global warming, many governments are turning to hydroelectric power. But, the research also suggests that methylmercury concentrations from flooding for hydroelectric development will be far greater than those expected from climate change.

The research, published in PNAS, began as a review of the environmental impact assessment for the Muskrat Falls hydroelectric dam in Labrador, Canada. In 2017, the dam will flood a large region upstream from an estuarine fjord called Lake Melville.

The communities along the shores of Lake Melville are predominantly Indigenous and rely on the lake as a primary source of food. One of these communities — and two-thirds of Lake Melville — is part of Nunatsiavut, the first autonomous region in Canada governed by Inuit. When the impact report predicted no adverse downstream effects on Lake Melville, the Nunatsiavut Government reached out to Elsie Sunderland, associate professor of environmental engineering and environmental health, for help.

“All of the methylmercury from the rivers feeding into Lake Melville (pictured) and from the

sediment at the bottom of the lake couldn’t account for the levels in the water,” said postdoctoral

fellow Amina Schartup. “There was something else going on here.” Photo by Prentiss H. Balcom

Four years later, that initial review has morphed into a multi-pronged investigation that has led to important scientific discoveries about how methylmercury accumulates in the ecosystem and how it will impact communities who rely on the ecosystem for food and resources.

What’s happening

Sunderland and her team — including lab manager Prentiss H. Balcom and postdoctoral fellow Amina Schartup, the paper’s first author — made their first trip to Happy Valley Goose Bay, along the western shores of Lake Melville, in 2012. There, they took a 10-day journey across the lake on a fishing boat to measure baseline methylmercury levels.

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Paper tubes make stiff origami structures

Georgia Tech professor Glaucio Paulino and University of Illinois graduate researcher

Evgueni Filipov developed an origami “zippered tube” folding pattern that allows them to build

structures with much greater stiffness than a single sheet of paper. They collaborated with

University of Tokyo professor Tomohiro Tachi (not pictured). Photo by Rob Felt

(September 8, 2015)  From shipping and construction to outer space, origami could put a folded twist on structural engineering.

Researchers from the University of Illinois at Urbana-Champaign, the Georgia Institute of Technology and the University of Tokyo have developed a new “zippered tube” configuration that makes paper structures that are stiff enough to hold weight yet can fold flat for easy shipping and storage. Their method could be applied to other thin materials, such as plastic or metal, to transform structures from furniture to buildings to microscopic robots.

Illinois graduate researcher Evgueni Filipov, Georgia Tech professor Glaucio Paulino and University of Tokyo professor Tomohiro Tachi published their work in the Proceedings of the National Academy of Sciences.

Origami structures would be useful in many engineering and everyday applications, such as a robotic arm that could reach out and scrunch up, a construction crane that could fold to pick up or deliver a load, or pop-up furniture. Paulino sees particular potential for quick-assembling emergency shelters, bridges and other infrastructure in the wake of a natural disaster.

“Origami became more of an objective for engineering and a science just in the last five years or so,” Filipov said. “A lot of it was driven by space exploration, to be able to launch structures compactly and deploy them in space. But we’re starting to see how it has potential for a lot of different fields of engineering. You could prefabricate something in a factory, ship it compactly and deploy it on site.”

Origami "zipper tubes," interlocking zigzag paper tubes, can be configured to build a variety

of structures that have stiffness and function, but can fold compactly for storage or shipping.

Click to see a slideshow Photo by Rob Felt

The researchers use a particular origami technique called Miura-ori folding. They make precise, zigzag-folded strips of paper, then glue two strips together to make a tube. While the single strip of paper is highly flexible, the tube is stiffer and does not fold in as many directions.

The researchers tried coupling tubes in different configurations to see if that added to the structural stiffness of the paper structures. They found that interlocking two tubes in zipper-like fashion made them much stiffer and harder to twist or bend. The structure folds up flat, yet rapidly and easily expands to the rigid tube configuration.

source >>

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Aspirin could hold the key to supercharged cancer immunotherapy

(September 6, 2015)  Giving cancer patients aspirin at the same time as immunotherapy could dramatically boost the effectiveness of the treatment, according to new research published in the journal Cell today (Thursday).

Francis Crick Institute researchers, funded by Cancer Research UK, have shown that skin, breast and bowel cancer cells often produce large amounts of prostaglandin E2 (PGE2). This molecule dampens down the immune system's normal response to attack faulty cells, which helps cancer to hide. It is a trick that allows the tumour to thrive and may explain why some immunotherapy treatments have not been as effective as hoped.

Aspirin is part of a group of molecules called COX inhibitors, which stop the production of PGE2 and help reawaken the immune system. Combining immunotherapy with aspirin or other COX inhibitors substantially slowed bowel and melanoma skin cancer growth in mice, compared to immunotherapy alone*.

Study author Professor Caetano Reis e Sousa, senior group leader at the Francis Crick Institute, said: "We've added to the growing evidence that some cancers produce PGE2 as a way of escaping the immune system. If you can take away cancer cells' ability to make PGE2 you effectively lift this protective barrier and unleash the full power of the immune system.

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Poplar trees are best bet for biofuel in UW-led research project

Poplar materials, including bark, leaves and wood, are used to make

cellulosic ethanol.Dennis Wise/University of Washington

(September 6, 2015)  Groves of poplar trees could one day fuel our vehicles and be the source of chemicals that we use in our daily lives.

The research, led by the University of Washington, will seed the world’s first wood-based cellulosic ethanol production facility. The handful of other cellulosic ethanol factories use agricultural waste to convert feedstock into sustainable transportation fuels.

The U.S. Department of Agriculture-funded project is in its final year, and the consortium of 10 academic institutions and private companies will gather at the UW Sept. 8-10 to share results and finalize research projects. They identified hybrid poplars as a beneficial feedstock because of the tree’s fast growth, year-round availability and wood that is readily broken down to fermentable sugars.

ZeaChem, a Colorado-based biofuels company and one of the industry partners in this study, is moving ahead with plans to build a commercial production facility in Boardman, Oregon, in 2016 that will produce fuel-grade ethanol and bio chemicals.

“We’ve established that poplar is a viable and sustainable feedstock for the production of fuels and bio-based chemicals,” said Rick Gustafson, a UW professor of bioresource science and engineering, who leads the project. “We’ve provided fundamental information that our industry partners can use to convince investors that production of fuels and chemicals from poplar feedstock is a great investment.”

Shannon Ewanick with the UW’s Biofuels and Bioproducts Laboratory operates

the pretreatment reactor, known as a “steam gun.”Dennis Wise/University of Washington

The research team, called Advanced Hardwood Biofuels Northwest, set up five demonstration tree farms with different varieties of poplar. None of the trees is genetically engineered, but instead researchers bred them to thrive in different environments and to grow fast. The trees can gain up to 20 feet a year, allowing for a harvest every two or three years.

“They grow like mad,” Gustafson said. “The production growth rate of these trees has just been phenomenal.”

When a poplar tree is cut, its stump naturally sprouts new shoots and the next generation of trees grow out of the parent stumps. Each tree can go through about six cycles of this regrowth before new poplars must be planted, Gustafson said.

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Earth observations show how nitrogen may be detected on exoplanets, aiding search for life

The Earth as seen by the Polychromatic Imaging Camera aboard NASA’s

Deep Space Climate Observatory satellite, July 2015.NASA

(September 6, 2015)  Observations of nitrogen in Earth’s atmosphere by a NASA spacecraft 17 million miles away are giving astronomers fresh clues to how that gas might reveal itself on faraway planets, thus aiding in the search for life.

Finding and measuring nitrogen in the atmosphere of an exoplanet — one outside our solar system — can be crucial to determining if that world might be habitable. That’s because nitrogen can provide clues to surface pressure. If nitrogen is found to be abundant in a planet’s atmosphere, that world almost certainly has the right pressure to keep liquid water stable on its surface. Liquid water is one of the prerequisites for life.

Should life truly exist on an exoplanet, detecting nitrogen as well as oxygen could help astronomers verify the oxygen’s biological origin by ruling out certain ways oxygen can be produced abiotically, or through means other than life.

The trouble is, nitrogen is hard to spot from afar. It’s often called an “invisible gas” because it has few light-altering features in visible or infrared light that would make it easy to detect. The best way to detect nitrogen in a distant atmosphere is to measure nitrogen molecules colliding with each other. The resulting, instantaneously brief “collisional pairs” create a unique and discernable spectroscopic signature.

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Fortifying Computer Chips for Space Travel

Dec. 4, 2014 — At Space Launch Complex 37 at Cape Canaveral Air Force Station in

Florida, fueling of the Delta IV Heavy rocket has been completed. The countdown continues

for launch of NASA’s Orion spacecraft.Photo credit: NASA

(September 6, 2015)  Berkeley Lab's particle accelerator blasts microprocessors with high-energy beams to toughen them up.

Space is cold, dark, and lonely. Deadly, too, if any one of a million things goes wrong on your spaceship. It’s certainly no place for a computer chip to fail, which can happen due to the abundance of radiation bombarding a craft. Worse, ever-shrinking components on microprocessors make computers more prone to damage from high-energy radiation like protons from the sun or cosmic rays from beyond our galaxy.

It’s a good thing, then, that engineers know how to make a spaceship’s microprocessors more robust. To start, they hit them with high-energy ions from particle accelerators here on Earth. It’s a radiation-testing process that finds a chip’s weak spots, highlighting when, where, and how engineers need to make the microprocessor tougher.

One of the most long-lived and active space-chip testing programs is at the U.S. Department of Energy’s Lawrence Berkeley National Lab (Berkeley Lab). Sitting just up the hill from UC Berkeley, in Berkeley Lab’s Building 88, is the 88-Inch Cyclotron, a machine that accelerates ions to high energies along a circular path.

Michael Johnson, Nuclear Science Division, in caves 4A,4B of the 88 inch Cyclotron.

Photo credit: Roy Kaltschmidt, Berkeley Lab

Since 1979, most American satellites have had one or more electronic components go through Berkeley Lab’s cyclotron, says Mike Johnson, research coordinator at the 88-Inch Cyclotron. Chips on the Mars rover Curiosity, chips on the Solar Dynamics Observatory, chips on the space shuttles, and chips on the International Space Station have all been put through the paces in the particle accelerator before launch. The goal is relatively simple, says Johnson: it’s to “piece together a curve of the likelihood that there’s going to be an error.”

Mistake-free Mars

NASA has publicly announced that it plans to send astronauts to Mars by the 2030s. A Mars trip would be a multi-year mission that will expose the crew and vessel to more radiation than any other manned mission in history. Currently, Johnson says, some electronics destined for NASA’s new Mars-bound space craft called Orion are being tested at the facility.

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Silk bio-ink could help advance tissue engineering with 3-D printers

Scientists have developed a silk-based, 3-D printer ink for use in biomedical

implants or tissue engineering. Credit: American Chemical Society

(September 5, 2015)  Advances in 3-D printing have led to new ways to make bone and some other relatively simple body parts that can be implanted in patients. But finding an ideal bio-ink has stalled progress toward printing more complex tissues with versatile functions — tissues that can be loaded with pharmaceuticals, for example. Now scientists, reporting in the journal ACS Biomaterials Science & Engineering, have developed a silk-based ink that could open up new possibilities toward that goal.

Most inks currently being developed for 3-D printing are made of thermoplastics, silicones, collagen and gelatin or alginate. But there are limits to how these inks can be used. For example, the temperatures, pH changes and crosslinking methods that may be required to toughen some of these materials can damage cells or other biological components that researchers would want to add to the inks. Additives, such as cytokines and antibiotics, are useful for directing stem cell functions and controlling infections, respectively. To address these bio-ink limitations, David L. Kaplan and colleagues turned to silk protein and developed a way to avoid these harsh processing conditions.

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Self-sweeping laser could dramatically shrink 3D mapping systems

This self-sweeping laser couples an optical field with the mechanical motion of a

high-contrast grating (HCG) mirror. The HCG mirror is supported by mechanical springs

connected to layers of semiconductor material. The red layer represents the laser’s gain

(for light amplification), and the blue layers form the system’s second mirror.

The force of the light causes the top mirror to vibrate at high speed. The vibration allows

the laser to automatically change color as it scans. (Schematic by Weijian Yang)

(September 5, 2015)  A new approach that uses light to move mirrors could usher in a new generation of laser technology for a wide range of applications, including remote sensing, self-driving car navigation and 3D biomedical imaging.

A team of UC Berkeley engineers led by Connie Chang-Hasnain, a professor of electrical engineering and computer sciences, used a novel concept to automate the way a light source changes its wavelength as it sweeps the surrounding landscape. They report their findings in the journal Scientific Reports, published Thursday, Sept. 3.

The advance could have implications for imaging technology using LIDAR, or light detection and ranging, and OCT, or optical coherence tomography.

“Our paper describes a fast, self-sweeping laser that can dramatically reduce the power consumption, size, weight and cost of LIDAR and OCT devices on the market today,” said Chang-Hasnain, chair of the Nanoscale Science and Engineering Graduate Group at UC Berkeley. “The advance could shrink components that now take up the space of a shoebox down to something compact and lightweight enough for smartphones or small UAVs [unmanned aerial vehicles].”

LIDAR works by shining a beam of light at a target and measuring the amount of time it takes to bounce back. Because the speed of light is constant, this system can then be used to calculate distance. Self-driving vehicles and remote sensing technology use LIDAR for navigation and the creation of 3D maps.

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'Hedgehog' Robots Hop, Tumble in Microgravity

While a Mars rover can't operate upside down, the Hedgehog robot can function

regardless of which side lands up. Credit: NASA/JPL-Caltech/Stanford

(September 5, 2015)  Hopping, tumbling and flipping over are not typical maneuvers you would expect from a spacecraft exploring other worlds. Traditional Mars rovers, for example, roll around on wheels, and they can't operate upside-down. But on a small body, such as an asteroid or a comet, the low-gravity conditions and rough surfaces make traditional driving all the more hazardous.

Enter Hedgehog: a new concept for a robot that is specifically designed to overcome the challenges of traversing small bodies. The project is being jointly developed by researchers at NASA's Jet Propulsion Laboratory in Pasadena, California; Stanford University in Stanford, California; and the Massachusetts Institute of Technology in Cambridge.

NASA's C-9 aircraft for microgravity research gave two Hedgehog prototypes

a ride in June 2015 to test their maneuvers. Credit: NASA

"Hedgehog is a different kind of robot that would hop and tumble on the surface instead of rolling on wheels. It is shaped like a cube and can operate no matter which side it lands on," said Issa Nesnas, leader of the JPL team.

The basic concept is a cube with spikes that moves by spinning and braking internal flywheels. The spikes protect the robot's body from the terrain and act as feet while hopping and tumbling.

"The spikes could also house instruments such as thermal probes to take the temperature of the surface as the robot tumbles," Nesnas said.

Two Hedgehog prototypes -- one from Stanford and one from JPL -- were tested aboard NASA's C-9 aircraft for microgravity research in June 2015. During 180 parabolas, over the course of four flights, these robots demonstrated several types of maneuvers that would be useful for getting around on small bodies with reduced gravity. Researchers tested these maneuvers on different materials that mimic a wide range of surfaces: sandy, rough and rocky, slippery and icy, and soft and crumbly.

"We demonstrated for the first time our Hedgehog prototypes performing controlled hopping and tumbling in comet-like environments," said Robert Reid, lead engineer on the project at JPL.

Hedgehog's simplest maneuver is a "yaw," or a turn in place. After pointing itself in the right direction, Hedgehog can either hop long distances using one or two spikes or tumble short distances by rotating from one face to another. Hedgehog typically takes large hops toward a target of interest, followed by smaller tumbles as it gets closer.

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