Tech

AMES, Iowa - Just like a chameleon changes its skin color in response to its environment, engineers have found a way for liquid metal - and potentially solid metal - to change its surface structure in response to heat.

Treating particles of liquid metal alloys with heat causes them to roughen their surfaces with tiny spheres or nanowires, Iowa State University engineers reported in a paper featured on the cover of the Jan. 2 issue of the journal Angewandte Chemie.

Control the heat and you can control the surface patterns, said Martin Thuo, an Iowa State assistant professor of materials science and engineering, a co-founder of Ames startup SAFI-Tech Inc. and lead author of the paper.

And what could that tunable surface patterning lead to?

The technology could "inspire design of 'smart' alloy systems that evolve the surface patterns and their composition with temperature (or analogous stimuli) for applications ranging from sensing to catalysis," Thuo and his research team wrote in their paper.

The paper's co-authors are Andrew Martin and Winnie Kiarie, Iowa State doctoral students in materials science and engineering; and Boyce Chang, a postdoctoral fellow at the University of California, Berkeley, who earned his doctoral degree at Iowa State.

The research team started with a liquid metal alloy of gallium, indium and tin synthesized into particles covered with a smooth oxide shell that has been chemically stabilized. As the particles are heated, the surface thickens and stiffens and begins to behave more like a solid.

Eventually the surface breaks, allowing the liquid metal inside to come to the surface. The most reactive, gallium, breaks through first. More heat brings indium to the surface. And the highest heat - about 1,600 degrees Fahrenheit - brings out florets of tin.

This movement from the under-layer to the surface allows a liquid metal particle to "continuously invert its composition under thermal stimuli," the researchers wrote in the paper.

"The particles are responding to a certain level of heat and releasing a specific element based on temperature, just as a chameleon responds to the color of its environment," Thuo said. "That's why we say they're chameleon metals - but responding to heat, not to color as the reptile does."

Kiarie said the metal particles are responding to a very controlled environment - time, temperature and oxygen levels are carefully controlled by the researchers.

That allows the researchers to predict and program the exact surface texture of the particles.

Martin said the technology could be used to fine-tune a metal's performance as a catalyst or its ability to absorb compounds.

The researchers also say the technology will work with other metal alloys.

"This is not unique to these materials," Thuo said. "This is a behavior of metals in general. Other metals subject to the same treatment should do this. This is a universal property of metals."

That could make chameleon metals a very interesting and useful technology: "When you talk about smart materials, polymers come to mind," Thuo said. "But metals can do this, too. But it's a big beast - you just need to know how to tame it."

Tokyo, Japan - A scientist from Tokyo Metropolitan University and coworkers have discovered that a specific insulin-like peptide called ILP2 regulates the size of "weapons" in Gnatocerus cornutus beetles in different nutritional environments. They found diminished mandible size when expression of the peptide was suppressed, and that it was specifically expressed in the "fat body", where beetles store nutrients. This has important implications for understanding how striking growth occurs in different environments for different organisms.

From deer antlers to beetle horns, the animal kingdom is full of examples of exaggerated ornaments and weapons which derive from sexual selection. Their growth and size may vary significantly from one specimen to another and give rise to distinct mating tactics like fighting, sneaking, or dispersing to areas with less competition. This variation is often correlated with body size or "condition" in a relationship known as positive allometry. Despite the importance of condition dependent growth of these features, the mechanism behind how the environment affects the complex development of these observable features remains poorly understood.

Insulin-like peptides (ILPs) and growth factors (IGFs) are found in a wide range of both invertebrates and vertebrates, like humans, and are thought to play common roles related to growth and metabolism. Recent work into the genetics of insects has revealed a wide variety of ILPs playing different functional roles. Examples include fruit flies which have 8, pea aphids with 10 and silkworms with over 40. Yet, despite some understanding of what ILPs do in model organisms like fruit flies, we know little about their function outside of the lab, in particular, how their molecular function contributes to phenotypic complexity, or the diversification of traits in a particular natural environment.

Thus, a team led by Yasukazu Okada from Tokyo Metropolitan University examined the broad-horned flour beetle, G. cornutus. Found in grain stores and factories, male flour beetles have exaggerated mandibles for male-male combat; large beetles have larger mandibles, and past work has found it is linked to better nutrition as a larva. This makes it ideal for studying the molecular basis for conditional growth. The team examined the beetle's genome, and found five different ILP genes, labeled GcorILP1 to 5, all encoding for a different ILP (ILP1 to 5). Firstly, they found that sufficiently fed larger larvae showed an elevated expression of ILP2 at the pre-pupa stage, while "poorly" fed smaller larvae did not. They also found that the same peptide was specifically expressed in the fat body; smaller larvae expressed less of the peptide as a consequence of having less fat. Furthermore, by using a technique known as RNA interference to impede the expression of ILP2, they found a direct correlation between so-called GcorILP2 "knock-down" (KD) and diminished mandible size, not to mention less of a correlation with how well the larvae were fed.

This is the first discovery of how a specific ILP is connected to sexually selected exaggerated traits under different conditions. It clearly demonstrates how the functional diversity of ILPs has led to particular peptides playing very specific roles and is an important step in elucidating how the whole insulin/insulin-like growth factor signaling pathway affects complex development mechanisms and evolution.

English and Italian speakers with dementia-related language impairment experience distinct kinds of speech and reading difficulties based on features of their native languages, according to new research by scientists at the UC San Francisco Memory and Aging Center and colleagues at the Neuroimaging Research Unit and Neurology Unit at the San Raffaele Scientific Institute in Milan.

Neurologists had long assumed that brain diseases that impact language abilities would manifest in essentially the same way in patients around the world. But recent discoveries have begun to question that assumption. For instance, Italian speakers with dyslexia tend to have less severe reading impairment than English or French speakers due to Italian's simpler and more phonetic spelling.

"Clinical criteria for diagnosing disorders that affect behavior and language are still mainly based on studies of English speakers and Western cultures, which could lead to misdiagnosis if people who speak different languages or come from another cultural background express symptoms differently," said study senior author Maria Luisa Gorno-Tempini, MD, PhD, a professor of neurology and psychiatry and the Charles Schwab Distinguished Professor in Dyslexia and Neurodevelopment at the UCSF Memory and Aging Center. "It is critical going forward that studies take language and cultural differences into account when studying brain disorders that affect higher cognitive functions -- which we know are greatly impacted by culture, environment, and experience."

The new study, published January 10, 2020 in Neurology, the medical journal of the American Academy of Neurology, focused on patients with primary progressive aphasia (PPA), a neurodegenerative disorder that affects language areas in the brain, a condition often associated with Alzheimer's disease, frontotemporal lobar degeneration, and other dementia disorders.

The researchers recruited 20 English-speaking PPA patients from the UCSF Memory and Aging Center and 18 Italian-speaking PPA patients from San Raffaele Hospital, all of whom shared a variant of PPA characterized by difficulty producing or pronouncing words -- so-called non-fluent PPA.

"We wanted to study patients with PPA to understand whether people from different language backgrounds actually experienced the disease differently, and what that might mean for how we try to help patients remain resilient to the disease," said study lead author Elisa Canu, PhD, a neuropsychologist and researcher in the San Raffaele Scientific Institute's Neuroimaging Research Unit, which is led by co-author Massimo Filippi, MD, full professor of neurology at the affiliated Vita-Salute San Raffaele University, and director of the neurology and neurophysiology units at the San Raffaele Hospital.

Cognitive tests and MRI brain scans revealed similar cognitive function and comparable levels of brain degeneration in the two groups. But when the researchers compared their performance on a battery of linguistic tests, they observed a key difference.

English speakers had more trouble pronouncing words -- the traditional hallmark of nonfluent PPA -- and tended to speak less than usual. In contrast, Italian speakers with the same disorder had fewer pronunciation difficulties but tended to produce much shorter and grammatically simpler sentences. For example, when asked to describe a drawing of a family at a lake house picnicking and flying a kite, Italian speakers with non-fluent PPA might respond (in Italian): "The man and the woman and the dog"; "Boat in the water"; "Family have picnic"; "There is a kite".

"We think this is specifically because the consonant clusters that are so common in English pose a challenge for a degenerating speech-planning system," said Gorno-Tempini, who directs the language neurobiology laboratory at the UCSF Memory and Aging Center, and is co-director of the UCSF Dyslexia Center and the recently launched UCSF-UC Berkeley Schwab Dyslexia and Cognitive Diversity Center. "In contrast, Italian is easier to pronounce, but has much more complex grammar, and this is how Italian speakers with PPA tend to run into trouble."

The results are important for efforts to ensure accurate diagnoses for patients with PPA across different cultures: in the current study the Italian speakers do not match the established diagnostic criteria for nonfluent PPA as closely as the English speakers, since the criteria are based on studies of English-speaking patients.

"This means that there are probably many people around the world -- including non-native English speakers in the U.S. -- who are not getting the right diagnosis because their symptoms don't match what is described in clinical manuals based on studies of native English speakers," said Gorno-Tempini.

The researchers acknowledge that this is a small study and cannot completely exclude the possibility that differences in dementia severity, undetected anatomical differences and differences in education level between Italian and English participants could be confounding factors in the results.

Future studies in partnership with the Global Brain Health Institute (GBHI), a joint effort of UCSF and Trinity College Dublin to reduce the impact of dementia around the world, will attempt to replicate the findings in larger groups of patients, and look for further differences between speakers of even more diverse, non-Western languages, such as Chinese and Arabic.

"We hope that such studies will advance our understanding of the brain science underlying language and language disorders, raise awareness of health disparities in dementia treatment, and ultimately improve care for all patients," Gorno-Tempini said.

HOUSTON -- (Jan. 10, 2020) -- Rice University engineers have created a light-powered nanoparticle that could shrink the carbon footprint of a major segment of the chemical industry.

The particle, tiny spheres of copper dotted with single atoms of ruthenium, is the key component in a green process for making syngas, or synthesis gas, valuable chemical feedstock that's used to make fuels, fertilizer and many other products. Researchers from Rice, UCLA and the University of California, Santa Barbara (UCSB), describe the low-energy, low-temperature syngas production process this week in Nature Energy.

"Syngas can be made in many ways, but one of those, methane dry reforming, is increasingly important because the chemical inputs are methane and carbon dioxide, two potent and problematic greenhouse gases," said Rice chemist and engineer Naomi Halas, a co-corresponding author on the paper.

Syngas is a mix of carbon monoxide and hydrogen gas that can be made from coal, biomass, natural gas and other sources. It's produced at hundreds of gasification plants worldwide and is used to make fuels and chemicals worth more than $46 billion per year, according to a 2017 analysis by BCC Research.

Catalysts, materials that spur reactions between other chemicals, are critical for gasification. Gasification plants typically use steam and catalysts to break apart hydrocarbons. The hydrogen atoms pair up to form hydrogen gas, and the carbon atoms combine with oxygen in the form of carbon monoxide. In dry reforming, the oxygen atoms come from carbon dioxide rather than steam. But dry reforming hasn't been attractive to industry because it typically requires even higher temperatures and more energy than steam-based methods, said study first author Linan Zhou, a postdoctoral researcher at Rice's Laboratory for Nanophotonics (LANP).

Halas, who directs LANP, has worked for years to create light-activated nanoparticles that insert energy into chemical reactions with surgical precision. In 2011, her team showed it could boost the amount of short-lived, high-energy electrons called "hot carriers" that are created when light strikes metal, and in 2016 they unveiled the first of several "antenna reactors" that use hot carriers to drive catalysis.

One of these, a copper and ruthenium antenna reactor for making hydrogen from ammonia, was the subject of a 2018 Science paper by Halas, Zhou and colleagues. Zhou said the syngas catalyst uses a similar design. In each, a copper sphere about 5-10 nanometers in diameter is dotted with ruthenium islands. For the ammonia catalysts, each island contained a few dozen atoms of ruthenium, but Zhou had to shrink these to a single atom for the dry reforming catalyst.

"High efficiency is important for this reaction, but stability is even more important," Zhou said. "If you tell a person in industry that you have a really efficient catalyst they are going to ask, 'How long can it last?'"

Zhou said the question is important for producers, because most gasification catalysts are prone to "coking," a buildup of surface carbon that eventually renders them useless.

"They cannot change the catalyst every day," Zhou said. "They want something that can last."

By isolating the active ruthenium sites where carbon is dissociated from hydrogen, Zhou reduced the chances of carbon atoms reacting with one another to form coke and increased the likelihood of them reacting with oxygen to form carbon monoxide.

"But single-atom islands are not enough," he said. "For stability, you need both single atoms and hot electrons."

Zhou said the team's experimental and theoretical investigations point to hot carriers driving hydrogen away from the reactor surface.

"When hydrogen leaves the surface quickly, it's more likely to form molecular hydrogen," he said. "It also decreases the possibility of a reaction between hydrogen and oxygen, and leaves the oxygen to react with carbon. That's how you can control with the hot electron to make sure it doesn't form coke."

Halas said the research could pave the way "for sustainable, light-driven, low-temperature, methane-reforming reactions for production of hydrogen on demand."

"Beyond syngas, the single-atom, antenna-reactor design could be useful in designing energy-efficient catalysts for other applications," she said.

The technology has been licensed by Syzygy Plasmonics, a Houston-based startup whose co-founders include Halas and study co-author Peter Nordlander.

Halas is Rice's Stanley C. Moore Professor of Electrical and Computer Engineering and professor of chemistry, bioengineering, physics and astronomy, and materials science and nanoengineering. Nordlander is the Wiess Chair and Professor of Physics and Astronomy, and professor of electrical and computer engineering, and materials science and nanoengineering.

Additional co-authors include Chao Zhang, Dayne Swearer, Shu Tian, Hossein Robatjazi, Minhan Lou, Liangliang Dong and Luke Henderson, all of Rice; John Mark Martirez and Emily Carter, both of UCLA; and Jordan Finzel and Phillip Christopher of UCSB.

Curtis Menyuk, professor of computer science and electrical engineering at the University of Maryland, Baltimore County (UMBC), has collaborated with a team directed by Philip Russell at the Max-Planck Institute for the Science of Light (MPI) in Erlangen, Germany, to gain insight into naturally-occurring molecular systems using optical solitons in lasers. Optical solitons are packets of light that are bound together and move at a constant speed without changing shape. This work, published in Nature Communications, was initiated while Menyuk was a Humboldt Senior Research Fellow in the Russell Division at MPI.

Solitons are ubiquitous in nature, and a tsunami wave is an example of a naturally-occuring soliton. Optical solitons in lasers have numerous applications and are used to measure frequencies with unprecedented accuracy. In particular, they have been used to measure time, enhance GPS technology, and detect distant planets.

Optical solitons can be tightly bound to each other in lasers to make soliton molecules that are analogous to natural molecules, which consist of covalently-bound atoms. Menyuk and his MPI colleagues have demonstrated experimentally that this concept can be extended to create optical supramolecules.

Optical supramolecules are large, complex arrays of weakly bound optical molecules that are similar to naturally-occurring supramolecules, which are weakly bound by non-covalent bonds. Naturally-occurring supramolecules are used to chemically store and manipulate information that biological systems need to function. These supramolecules are known to play a fundamental role in biochemistry, particularly in "host-guest" chemistry, which describes two or more molecules that are held together structurally by forces other than covalent bonds.

The work of Menyuk and his collaborators brought together these two strands of seemingly unrelated thought: optical solitons and supramolecules. The research team showed that it is possible to store and manipulate information that is encoded in the configuration of solitons that make up an optical supramolecule.

"Bringing together ideas from two apparently unrelated areas of science is one of the most powerful tools that engineers have for making progress," Menyuk says.

Optical analogs to other physical and naturally-occurring systems have played an important role in enhancing our understanding of these systems, and this understanding can lead to new applications. By mimicking the processes that biological systems use in a large-scale laser system that can be manipulated and understood with relative ease, Menyuk and his colleagues hope to gain a better understanding of those systems and open the door to new biomimetic applications.

Researchers at University of California San Diego School of Medicine have discovered how a new immune system works to protect bacteria from bacteriophages (phages), viruses that specifically infect bacteria. This new system is unusual in that it works by abortive infection -- the infected bacterial cell self-destructs to keep the infection from spreading to other cells.

The pair of papers, published January 10, 2020 by Molecular Cell, provides new information that could be employed to improve treatment of multidrug-resistant bacterial infections by refining phage therapy or even purposefully triggering bacterial self-destruction.

"Abortive infection is an old concept, but it's still controversial -- a bacterial cell essentially takes one for the team, killing itself rather than being used to produce more phages," said senior author Kevin Corbett, PhD, associate professor of cellular and molecular medicine at UC San Diego School of Medicine.

"It's been debated whether or not it's logical, from an evolutionary standpoint, for single-celled organisms to do this. But if we think of bacteria as a cooperative community, a biofilm, rather than as individual cells, it makes sense."

Corbett's lab wasn't always focused on bacteria. They typically study how mammalian cells divide to give rise to sperm and eggs, a process called meiosis. One aspect of meiosis that particularly interests them is how a specific protein family, called HORMA proteins, help maintain the stability of the genome during this specialized cell division. But when a 2015 study published by National Institutes of Health bioinformaticians predicted that some bacteria might also produce HORMA proteins, and that these proteins might be involved in a new kind of immune system, Corbett was intrigued.

"I'm a basic scientist, and I'm particularly interested in evolutionary connections between proteins and pathways that you would never expect to be related," said Corbett, who is also a visiting scientist at the San Diego Branch of the Ludwig Institute for Cancer Research. "So I wondered, what could these proteins be doing in bacteria?"

Almost 75,000 different bacteria have had their genomes sequenced. Of those, Corbett said this new defense system is found in approximately 10 percent. His team cloned the system, now called CBASS, into a laboratory strain of E. coli that is usually sensitive to phage infection. "We were thrilled to find that CBASS provided nearly absolute immunity to phages," Corbett said.

Digging deeper, the team went on to unravel a number of biochemical and structural details about the CBASS defense system, which contains several proteins. They found that the HORMA proteins sense the infection, then stimulate a second protein to synthesize a second messenger molecule. This molecule in turn activates a nuclease enzyme that destroys the bacterium's own genome, killing the cell and also keeping the phage from replicating and infecting other cells.

After falling out of favor a century ago, phages are once again being explored as a therapy for multidrug-resistant bacterial infections. According to Corbett, researchers including those at the UC San Diego Center for Innovative Phage Applications and Therapeutics might be able to use this new mechanistic information on bacterial immune systems to fine-tune phages to evade these systems, making phage therapies more effective.

"On the other hand, if we can find a way to activate this system with a drug, we might be able to get CBASS-containing bacteria to kill themselves," he said. "Doing something like that really requires that we have a clear understanding of the detailed mechanisms at play."

But first, Corbett said, the biggest question is understanding the sheer variety of CBASS systems.

"We've studied just one of more than 6,000 distinct CBASS systems, each of which encodes a different set of infection sensors, signaling proteins and effector proteins like the nuclease in our system. Understanding how these different sets of parts work together, and how bacteria have mixed and matched them as they've evolved, will give us a more complete picture of how it all works, and how we might best intervene."

Human behaviour is influenced by many things, most of which remain unconscious to us. One of these is a phenomenon known among perception psychologists as "pseudo-neglect". This refers to the observation that healthy people prefer their left visual field to their right and therefore devide a line regularly left of centre.

A study published on Friday, January 10, in the online magazine PLOS ONE now shows for the first time what effect this inconspicuous deviation had in the prehistoric past. A Slovak-German research team has investigated the alignment of early Neolithic houses in Central and Eastern Europe. Scientists of the Collaborative Research Centre (CRC) "Scales of Transformation" of Kiel University (CAU) and the Slovakian Academy of Sciences were able to prove that the orientation of newly built houses deviated by a small amount from that of existing buildings and that this deviation was regularly counterclockwise.

Archaeologist Dr. Nils Müller-Scheeßel, who coordinated the study within the CRC, says: "Researchers have long assumed that early Neolithic houses stood for about a generation, i.e. 30 to 40 years, and that new houses had to be built next to existing ones at regular intervals. By means of age determination using the radiocarbon method, we can now show that the new construction was associated with a barely perceptible rotation of the house axis counterclockwise. We see "Pseudoneglect" as the most likely cause of this."

This insight was made possible by the interpretation of one of the fastest growing archaeological data sets at present, namely the results of geophysical magnetics measurements. Differences in the earth's magnetic field are used to visualise archaeological features lying underground. Early Neolithic house ground plans belong to the best identifiable types of features.

"In recent years, we have discovered hundreds of Early Neolithic houses in our field of work in southwestern Slovakia using geophysical prospection methods. Excavating all these houses is neither possible nor desirable for reasons of monument conservation. The possibility of using "Pseudoneglect" to bring the houses into a relative sequence without excavation and thus to break down the settlement activity of an entire small region raises our research to a completely new level", says Mister Müller-Scheeßel enthusiastically. "Absolute dating using scientific methods must of course confirm the basic trend in every case".

The study also refers to comparable archaeological observations at other places and times, which show that similar changes in orientation also seem to apply to more recent prehistoric periods. The significance of "Pseudoneglect" thus extends far beyond the dating of early Neolithic houses.

Diabetic patients need to measure their blood-sugar level by drawing blood before and after a meal and it is easy to develop complications due to diabetes. Recently, a research team from POSTECH developed technology that allows diagnosis of diabetes and treatment of diabetic retinopathy just by wearing 'Smart Light-emitting diode (LED) Contact Lens.' With this technology, it is anticipated that development of wearable diagnostic and therapeutic devices for diabetes will be vitalized.

Professor Sei Kwang Hahn and his research team including his PhD student, Geon-Hui Lee, invented a smart photonic contact lens and a wearable medical device which can diagnose diabetes and treat diabetic retinopathy. Their new research results on photonic diagnosis and photonic therapy of diabetes are published on-line in the world's renowned journal, Nature Reviews Materials, as of January 7th in collaboration with the research group led by Zhenan Bao from Department of Chemical Engineering at Stanford University and David Myung from Stanford Medicine Ophthalmology.

The research team successfully developed a smart contact lens with integrated micro LED and photodetector which can measure glucose concentration in the conjunctival blood vessels by analyzing the NIR light. With this development, they succeeded in diabetic diagnosis.

Furthermore, they put their new smart LED contact lenses on rabbit eyes with diabetic retinopathy disease and irradiated light repeatedly for a month. As a result, they confirmed that there was significant reduction of angiogenesis (production of new blood vessels) in retina and verified clinical feasibility of the smart LED contact lens for the diabetic retinopathy therapy.

This newly developed device will not only let diabetic patients monitor their blood-sugar level in real-time but also enable medical treatment for retinopathy which is caused by diabetic complications.

Meanwhile, Professor Hahn and his research team have gained great attention from the academics by developing a smart contact lens that can diagnose diabetes by analyzing the glucose concentration in tears and deliver drugs to treat diabetic retinopathy for first time in the world. Preliminary clinical tests for the developers are expected to be done in the first half of this year.

On the basis of these results, recently, they also developed a smart wearable medical device that can do highly sensitive analysis on the glucose concentration in sweat and they verified that it could be clinically feasible for diabetic diagnosis. Also, with PHI Biomed company, they developed a blue-tooth system that can send data wirelessly allowing patients to check their diabetic diagnosis results on their mobile phones.

Professor Hahn who led the research mentioned about his future plan in his interview, "We developed a smart LED contact lens that can diagnose diabetes and treat diabetic retinopathy with light for the first time in the world. We are planning to commercialize these smart contact lenses and smart wearable medical devices in collaboration with Stanford Medicine."

Chemists have found a new use for the waste product of nuclear power - transforming an unused stockpile into a versatile compound which could be used to create valuable commodity chemicals as well as new energy sources.

Depleted uranium (DU) is a radioactive by-product from the process used to create nuclear energy. Many fear the health risks from DU, as it is either stored in expensive facilities or used to manufacture controversial armour-piercing missiles.

But, in a paper published in the Journal of the American Chemical Society, Professor Geoff Cloke, Professor Richard Layfield and Dr Nikolaos Tsoureas, all at the University of Sussex, have revealed that DU could, in fact, be more useful than we might think.

By using a catalyst which contains depleted uranium, the researchers have managed to convert ethylene (an alkene used to make plastic) into ethane (an alkane used to produce a number of other compounds including ethanol).

Their work is a breakthrough that could help reduce the heavy burden of large-scale storage of DU, and lead to the transformation of more complicated alkenes.

Prof Layfield said: "The ability to convert alkenes into alkanes is an important chemical reaction that means we may be able to take simple molecules and upgrade them into valuable commodity chemicals, like hydrogenated oils and petrochemicals which can be used as an energy source.

"The fact that we can use depleted uranium to do this provides proof that we don't need to be afraid of it as it might actually be very useful for us."

Working in collaboration with researchers at Université de Toulouse and Humboldt-Universität zu Berlin, the Sussex team discovered that an organometallic molecule based on depleted uranium could catalyse the addition of a molecule of hydrogen to the carbon-carbon double bond in ethylene - the simplest member of alkene family - to create ethane.

Prof. Cloke said: "Nobody has thought to use DU in this way before. While converting ethylene into ethane is nothing new, the use or uranium is a key milestone.

"The key to the reactivity were two fused pentagonal rings of carbon, known as pentalene, which help the uranium to inject electrons into ethylene and activate it towards addition of hydrogen."

Lovers of gold watches and heavy jewellery will be thrilled. The objects of their desire may someday become much lighter, but without losing any of their glitter. Especially with watches, a small amount of weight can make all the difference. No one wants to wear a heavy watch on their wrist, even if it's made of real gold. After a time, it becomes uncomfortable and annoying.

Formerly a postdoc in the ETH lab headed by Raffaele Mezzenga, Professor of Food and Soft Materials, Leonie van 't Hag set to create a new form of gold that weighs about five to ten times less than traditional 18-carat gold. The conventional mixture is usually three-quarters gold and one-quarter copper, with a density of about 15 g/cm3.

That's not true for this new lightweight gold: its density is just 1.7 g/cm3. And nonetheless it is still 18-carat gold. How was this miraculous lightness achieved Instead of a metal alloy element, van 't Hag, Mezzenga and colleagues used protein fibres and a polymer latex to form a matrix in which they embedded thin discs of gold nanocrystals. In addition, the lightweight gold contains countless tiny air pockets invisible to the eye. The researchers' study on this process has just been published in the journal Advanced Functional Materials.

Gold platelets and plastic melt into a material that can be easily processed mechanically.

Here's how the researchers create the new lightweight gold: first, they add the ingredients to water and create a dispersion. After adding salt to turn the dispersion into a gel, next they replace the water in it with alcohol.

Then they place the alcohol gel into a pressure chamber, where high pressures and a supercritical CO2 atmosphere enables miscibility of the alcohol and the CO2 gas; when the pressure is released, everything turns it into a homogeneous gossamer-like aerogel. Heat can be further applied afterwards to anneal the plastic polymers, thus transforming the material and compacting into the final desired shape, yet preserving the 18 carat composition.

Properties of a plastic workpiece

"This gold has the material properties of a plastic," Mezzenga says. If a piece of it falls onto a hard surface, it sounds like plastic. But it glimmers like metallic gold, and can be polished and worked into the desired form.

The researchers can even adjust the hardness of the material by changing the composition of the gold. They can also replace the latex in the matrix with other plastics, such as polypropylene. Since polypropylene liquifies at some specific temperature, "plastic gold" made with it can mimic the gold melting process, yet at much lower temperatures. Furthermore, the shape of the gold nanoparticle can change the material's colour: "nanoplatelets" produce gold's typical shimmer, while spherical nanoparticles of gold lend the material a violet hue.

"As a general rule, our approach lets us create almost any kind of gold we choose, in line with the desired properties," Mezzenga says.

Gold for watchmaking and electronics

Mezzenga points out that, while the plastic gold will be in particular demand in the manufacture of watches and jewellery, it is also suitable for chemical catalysis, electronics applications or radiation shielding. The researchers have applied for patents for both the process and the material.

Cancers are often made up of many cells which vary genetically to each other. These genetic differences mean the cancer may be particularly susceptible or resistant to a given treatment. As a result, identifying these variations can help clinicians decide which treatment is most likely to be successful for a specific patient.

Because simple clinical methods to test for genetic variation are vulnerable to missing a lot of cell-to-cell variability, recent computer tools have been developed to predict and characterise genetic diversity within clinical tumour samples. However, there is no existing common benchmarking approach to determine the most accurate computational methods.

The study, published in Nature Biotechnology, developed open-source software that can be used to judge the accuracy of computer predictions and establish this benchmark.

The team developed a simulation framework and scoring system to determine how accurately each algorithm predicted various measures of genetic diversity. These included: the proportion of cancerous cells in the tumour sample; the number of genetically different groups of cancerous cells in the tumour sample; the proportion of cells within each of these groups; which genetic mutations were in each group; and the genetic relationship between the groups.

"Our new framework provides a foundation which, over time as it is run against more tumours, will hopefully become a much-needed, unbiased, gold-standard benchmarking tool for assessing models that aim to characterise a tumour's genetic diversity," says joint-lead author Maxime Tarabichi, postdoc in the Cancer Genomics Laboratory at the Crick.

The researchers built upon an existing computer software to generate and analyse the 580 predictions in this research, adding new features to the software to create more realistic tumours. This tumour-simulation software and the marking framework are publicly available for other researchers to use either directly or to help develop their own scoring framework.

"Computer simulations in cancer genomics are helping us develop more accurate tools, as we understand where these tools perform well, and where they need improvement," says author Peter Van Loo, group leader in the Cancer Genomics Laboratory at the Crick. "Further developing these tools, so they more closely match real-life tumours, should ultimately help clinicians better match patients with personalised medicines."

In addition, the contributions of the various sources of total aluminium intake by the population were compared with one another. A high intake of aluminium compounds can cause, among other things, neurotoxic developmental disorders as well as damage the kidneys, liver and bones.

The BfR bases its assessment of the population's aluminium intake from food on the latest consumption and concentration data. Consumption data are collected through consumer surveys and provide information on which foods and how much of them are eaten by different consumer groups. The concentration data used show the average aluminium concentrations in the different food categories. For non-food products, such as cosmetics or packaging, the exposure assessment is also based on data regarding aluminium contents in the
products. Furthermore, typical application forms and quantities are taken into account.

For the risk assessment of aluminium intake, the BfR uses the tolerable weekly intake (TWI) derived from the European Food Safety Authority (EFSA) of 1 milligram aluminium per kilogram body weight.

The BfR's assessment shows that aluminium intake from food is lower compared to previous studies. Food is still a relevant, but no longer the population's main source of intake. If other relevant sources of aluminium intake are taken into account, such as aluminium containing
cosmetic products and uncoated food contact materials, the total intake can exhaust or even exceed the TWI for all age groups.

Consumers can influence their aluminium intake. Those who want to reduce their aluminium intake should use aluminium containing antiperspirants and toothpaste sparingly. When it comes to food, the BfR recommends a varied diet as well as alternating products and
brands. This can contribute to reducing the risk of permanently high aluminium intake caused by individual highly contaminated products. T
he BfR recommends, also for other reasons, exclusively breastfeeding infants in the first six months of life, if possible. The BfR generally
advises against the preparation and storage of, in particular, acidic and salty foods in uncoated aluminium articles or aluminium foil. If the aforementioned and avoidable sources of intake are reduced, most consumers are not expected to suffer any adverse health effects.

The BfR recommends that manufacturers take appropriate measures to reduce the amount of aluminium in food. These may include, for example, using raw materials with low aluminium content or coated materials for processing and packaging food.

There is still a high level of uncertainty in aluminium risk assessment because important data is still missing or can be interpreted differently. This concerns, for example, the question of how much aluminium is actually absorbed through the skin as well as the possible occurrence of certain long-term consequences of chronic exposure to aluminium.

January 10, 2020 - For the many men diagnosed with testosterone deficiency, losing weight can help increase testosterone levels. But certain diets - specifically a low-fat diet - may be associated with a small but significant reduction in testosterone, suggests a study in The Journal of Urology®, Official Journal of the American Urological Association (AUA). The Journal is published in the Lippincott portfolio by Wolters Kluwer.

"We found that men who adhered to a fat restrictive diet had lower serum testosterone than men on a nonrestrictive diet," according to the report by Jake Fantus, MD, of the Section of Urology, Department of Surgery, University of Chicago Medicine and colleagues from the Department of Urology, Northwestern University Feinberg School of Medicine, and the Department of Surgery, NorthShore University Health System. "However," the researchers add, "the clinical significance of small differences in serum T across diets is unclear."

Best Diet for Low Testosterone? No Single Right Answer Yet

Dr. Fantus and colleagues analyzed data on more than 3,100 men from a nationwide health study (the National Health and Nutrition Examination Survey, or NHANES). All participants had available data on diet and serum testosterone level.

Based on two-day diet history, 14.6 percent of men met criteria for a low-fat diet, as defined by the American Heart Association (AHA). Another 24.4 percent of men followed a Mediterranean diet high in fruits, vegetables, and whole grains but low in animal protein and dairy products. Only a few men met criteria for the AHA low-carbohydrate diet, so this group was excluded from the analysis.

The average serum testosterone level was 435.5 ng/dL (nanograms per deciliter). Serum testosterone was lower in men on the two restrictive diets: average 411 ng/dL for those on a low-fat diet and 413 ng/dL for those on the Mediterranean diet.

The associations were adjusted for other factors that can affect testosterone, including age, body mass index, physical activity, and medical conditions. After adjustment, the low-fat diet was significantly associated with reduced serum testosterone, although the Mediterranean diet was not.

Overall, 26.8 percent of men had testosterone levels less than 300 ng/dL. Despite the difference in average testosterone levels, the proportion of men with low testosterone was similar across all diet groups.

Low testosterone is highly prevalent in the United States, as approximately 500,000 men are diagnosed with testosterone deficiency each year. Testosterone deficiency can lead to problems, including decreased energy and libido, along with physiological alterations, including increased body fat and reduced bone mineral density.

In addition to medications, treatment for low testosterone often includes lifestyle modifications, such as exercise and weight loss. But the effects of diet on testosterone levels have been unclear. Because testosterone is a steroid hormone derived from cholesterol, changes in fat intake could alter testosterone levels. This new analysis of how diet affects serum testosterone provides evidence that a low-fat diet is associated with lower testosterone levels, compared to an unrestricted diet.

So what diet is best for men with testosterone deficiency? The answer remains unknown, according to the authors. In overweight or obese men, the health benefits of a low-fat diet likely far exceed the small reduction in serum testosterone. In contrast, for men who are not overweight, avoiding a low-fat diet "may be a reasonable component" of a multifaceted approach to increasing serum testosterone.

Dr. Fantus and coauthors note that further studies will be needed to corroborate their findings, and to clarify the mechanism by which restrictive diets reduce testosterone. But due to the difficulties of large-scale dietary studies, definitive trials are unlikely to be performed. "Therefore, our data represent a valuable approach towards answering this important question," the authors conclude.

Physicists in the Laboratory for Attosecond Physics at Ludwig-Maximilians-Universitaet (LMU) in Munich and at the Max Planck Institute for Quantum Optics (MPQ) have developed a novel type of detector that enables the oscillation profile of light waves to be precisely determined.

Light is hard to get a hold on. Light waves propagate with a velocity of almost 300,000 km per second, and the wavefront oscillates several hundred trillion times in that same interval. In the case of visible light, the physical distance between successive peaks of the light wave is less than 1 micrometer, and peaks are separated in time by less than 3 millionths of a billionth of a second (

Such pulses, which encompass only a few oscillations of the wave, can be used to investigate the behaviour of molecules and their constituent atoms, and the new detector is a very valuable tool in this context. Ultrashort laser pulses allow scientists to study dynamic processes at molecular and even subatomic levels. Using trains of these pulses, it is possible first to excite the target particles and then to film their responses in real time. In intense light fields, however, it is crucial to know the precise waveform of the pulses. Since the peak of the oscillating (carrier) light field and that of the pulse envelope can shift with respect to each other between different laser pulses, it is important to know the precise waveform of each pulse.

The team at LAP, which was led by Dr. Boris Bergues and Professor Matthias Kling, head of the Ultrafast Imaging and Nanophotonics Group, has now made a decisive breakthrough in the characterization of light waves. Their new detector allows them to determine the 'phase', i.e. the precise positions of the peaks of the few oscillation cycles within each and every pulse, at repetition rates of 10,000 pulses per second. To do so, the group generated circularly polarized laser pulses in which the orientation of the propagating optical field rotates like a clock hand, and then focused the rotating pulse in ambient air. The interaction between the pulse and molecules in the air results in a short burst of electric current, whose direction depends on the position of the peak of the light wave. By analyzing the exact direction of the current pulse, the researchers were able to retrieve the phase of the „carrier-envelope offset", and thus reconstruct the form of the light wave. Unlike the method conventionally employed for phase determination, which requires the use of a complex vacuum apparatus, the new technique works in ambient air and the measurements require very few extra components. „The simplicity of the setup is likely to ensure that it will become a standard tool in laser technology", explains Matthias Kling.

„We believe that this technique can also be applied to lasers with much higher repetition rates and in different spectral regions," says Boris Bergues. „Our methodology is of particular interest in the context of the characterization of extremely short laser pulses with high repetition rates, such as those generated at Europe's Extreme Light Infrastructure (ELI)," adds Prof. Matthias Kling. When applied to the latest sources of ultrashort laser pulses, this new method of waveform analysis could pave the way to technological breakthroughs, as well as permitting new insights into the behaviour of elementary particles 'in the fast lane'.

BOSTON -- A team of surgeons and specialists at Massachusetts General Hospital (MGH) is announcing an achievement in transplant surgery today, having recently performed the largest number of adult heart transplants in the country using what are known as Donation after Circulatory Death (DCD) donor hearts. The five transplants also include the first surgery of this kind for the New England region.

For decades, heart transplant cases in the U.S. have been dependent solely upon organs donated after brain death or irreversible loss of brain function. A DCD donor has brain function incompatible with life, but doesn't meet all criteria for brain death. Life support is removed and if the donor's heart stops beating within a certain window of time, death is declared and the organ is removed. Outside the body, blood circulation is re-established in the heart using a machine pump while it is being transferred to the recipient.

"This is a significant moment not only for MGH, but hopefully for transplant centers around the the country," said David D'Alessandro, MD, surgical director for Heart Transplantation at MGH. "Patients die each day while waiting for transplants, due to a major shortage of suitable organs. This is one way we can work toward addressing that gap."

The first adult DCD heart transplant in the U.S. was performed at Duke University Hospital last month. Duke and MGH are among five centers taking part in a clinical trial for DCD heart transplants, involving the use of the Organ Care System (OCS) designed by Massachusetts-based Transmedics. The portable OCS, often referred to as "heart in a box," restores the donor organ with warm, oxygenated blood, re-animating it until it can be safely transplanted. OCS was also used during the world's first DCD heart transplant in Australia in 2014 and in England's first DCD heart transplant in 2015.

"Recent studies have shown outcomes among DCD heart transplant patients overseas have been favorable," said James Markmann, MD, PhD, chief of the Division of Transplant Surgery at MGH. "I'm confident we will continue to see this program grow at MGH."

The DCD heart transplant trial is expected to run through August of 2021.