Tech

Commercial fast-charging stations subject electric car batteries to high temperatures and high resistance that can cause them to crack, leak, and lose their storage capacity, write engineers at the University of California, Riverside in a new study published in Energy Storage. To remedy this, the researchers have developed a method for charging at lower temperatures with less risk of catastrophic damage and loss of storage capacity.

Mihri Ozkan, a professor of electrical and computer engineering and Cengiz Ozkan, a professor of mechanical engineering in the Marlan and Rosemary Bourns College of Engineering, led a group that charged one set of discharged Panasonic NCR 18650B cylindrical lithium-ion batteries, found in Tesla cars, using the same industry fast-charging method as fast chargers found along freeways.

They also charged a set using a new fast-charging algorithm based on the battery's internal resistance, which interferes with the flow of electrons. The internal resistance of a battery fluctuates according to temperature, charge state, battery age, and other factors. High internal resistance can cause problems during charging.

The UC Riverside Battery Team charging method is an adaptive system that learns from the battery by checking the battery's internal resistance during charging. It rests when internal resistance kicks in to eliminate loss of charge capacity.

For the first 13 charging cycles, the battery storage capacities for both charging techniques remained similar. After that, however, the industry fast-charging technique caused capacity to fade much faster-- after 40 charging cycles the batteries kept only 60% of their storage capacity. Batteries charged using the internal resistance charging method retained more than 80% capacity after the 40th cycle.

At 80% capacity, rechargeable lithium-ion batteries have reached the end of their use life for most purposes. Batteries charged using the industry fast-charging method reached this point after 25 charging cycles, while internal resistance method batteries were good for 36 cycles.

"Industrial fast-charging affects the lifespan of lithium-ion batteries adversely because of the increase in the internal resistance of the batteries, which in turn results in heat generation," doctoral student and co-author Tanner Zerrin said.

Worse, after 60 charging cycles, the industry method battery cases cracked, exposing the electrodes and electrolyte to air and increasing the risk of fire or explosion. High temperatures of 60 degrees Celsius/140 degrees Fahrenheit accelerated both the damage and risk.

"Capacity loss, internal chemical and mechanical damage, and the high heat for each battery are major safety concerns, especially considering there are 7,104 lithium-ion batteries in a Tesla Model S and 4,416 in a Tesla Model 3," Mihri Ozkan said.

Internal resistance charging resulted in much lower temperatures and no damage.

"Our alternative adaptive fast charging algorithm reduced capacity fade and eliminated fractures and changes in composition in the commercial battery cells," Cengiz Ozkan said.

"The proposed adaptive fast charging provides a novel perspective for the design of fast charging technology for electric vehicles with better safety performance and longer battery lifespan," Bo Dong, a doctoral student and paper co-author said.

The researchers have applied for a patent on the adaptive internal resistance fast-charging algorithm that could be licensed by battery and car manufacturers. In the meantime, the UCR Battery Team recommends minimizing the use of commercial fast chargers, recharging before the battery is completely drained, and preventing overcharging.

A room-temperature bonding technique for integrating wide bandgap materials such as gallium nitride (GaN) with thermally-conducting materials such as diamond could boost the cooling effect on GaN devices and facilitate better performance through higher power levels, longer device lifetime, improved reliability and reduced manufacturing costs. The technique could have applications for wireless transmitters, radars, satellite equipment and other high-power and high-frequency electronic devices.

The technique, called surface-activated bonding, uses an ion source in a high vacuum environment to first clean the surfaces of the GaN and diamond, which activates the surfaces by creating dangling bonds. Introducing small amounts of silicon into the ion beams facilitates forming strong atomic bonds at room temperature, allowing the direct bonding of the GaN and single-crystal diamond that allows the fabrication of high-electron-mobility transistors (HEMTs).

The resulting interface layer from GaN to single-crystal diamond is just four nanometers thick, allowing heat dissipation up to two times more efficient than in the state-of-the-art GaN-on-diamond HEMTs by eliminating the low-quality diamond left over from nanocrystalline diamond growth. Diamond is currently integrated with GaN using crystalline growth techniques that produce a thicker interface layer and low-quality nanocrystalline diamond near the interface. Additionally, the new process can be done at room temperature using surface-activated bonding techniques, reducing the thermal stress applied to the devices.

"This technique allows us to place high thermal conductivity materials much closer to the active device regions in gallium nitride," said Samuel Graham, the Eugene C. Gwaltney, Jr. School Chair and Professor in Georgia Tech's George W. Woodruff School of Mechanical Engineering. "The performance allows us to maximize the performance for gallium nitride on diamond systems. This will allow engineers to custom design future semiconductors for better multifunctional operation."

The research, conducted in collaboration with scientists from Meisei University and Waseda University in Japan, was reported February 19 in the journal ACS Applied Materials and Interfaces. The work was supported by a multidisciplinary university research initiative (MURI) project from the U.S. Office of Naval Research (ONR).

For high-power electronic applications using materials such as GaN in miniaturized devices, heat dissipation can be a limiting factor in power densities imposed on the devices. By adding a layer of diamond, which conducts heat five times better than copper, engineers have tried to spread and dissipate the thermal energy.

However, when diamond films are grown on GaN, they must be seeded with nanocrystalline particles around 30 nanometers in diameter, and this layer of nanocrystalline diamond has low thermal conductivity - which adds resistance to the flow of heat into the bulk diamond film. In addition, the growth takes place at high temperatures, which can create stress-producing cracks in the resulting transistors.

"In the currently used growth technique, you don't really reach the high thermal conductivity properties of the microcrystalline diamond layer until you are a few microns away from the interface," Graham said. "The materials near the interface just don't have good thermal properties. This bonding technique allows us to start with ultra-high thermal conductivity diamond right at the interface."

By creating a thinner interface, the surface-activated bonding technique moves the thermal dissipation closer to the GaN heat source.

"Our bonding technique brings high thermal conductivity single crystal diamond closer to the hot spots in the GaN devices, which has the potential to reshape the way these devices are cooled," said Zhe Cheng, a recent Georgia Tech Ph.D. graduate who is the paper's first author. "And because the bonding takes place near room temperature, we can avoid thermal stresses that can damage the devices."

That reduction in thermal stress can be significant, going from as much as 900 megapascals (MPa) to less than 100 MPa with the room temperature technique. "This low stress bonding allows for thick layers of diamond to be integrated with the GaN and provides a method for diamond integration with other semiconductor materials," Graham said.

Beyond the GaN and diamond, the technique can be used with other semiconductors, such as gallium oxide, and other thermal conductors, such as silicon carbide. Graham said the technique has broad applications to bond electronic materials where thin interfacial layers are advantageous.

"This new pathway gives us the ability to mix and match materials," he said. "This can provide us with great electrical properties, but the clear advantage is a vastly superior thermal interface. We believe this will prove to be the best technology available so far for integrating wide bandgap materials with thermally-conducting substrates."

In future work, the researchers plan to study other ion sources and evaluate other materials that could be integrated using the technique.

"We have the ability to choose processing conditions as well as the substrate and semiconductor material to engineer heterogenous substrates for wide bandgap devices," Graham said. "That allows us to choose the materials and integrate them to maximize electrical, thermal and mechanical properties."

HOUSTON - (March 12, 2020) - It's not enough to take antibiotic-resistant bacteria out of wastewater to eliminate the risks they pose to society. The bits they leave behind have to be destroyed as well.

Researchers at Rice University's Brown School of Engineering have a new strategy for "trapping and zapping" antibiotic resistant genes, the pieces of bacteria that, even though theirs hosts are dead, can find their way into and boost the resistance of other bacteria.

The team led by Rice environmental engineer Pedro Alvarez is using molecular-imprinted graphitic carbon nitride nanosheets to absorb and degrade these genetic remnants in sewage system wastewater before they have the chance to invade and infect other bacteria.

The researchers targeted plasmid-encoded antibiotic-resistant genes (ARG) coding for New Delhi metallo-beta-lactamase 1 (NDM1), known to resist multiple drugs. When mixed in solution with the ARGs and exposed to ultraviolet light, the treated nanosheets proved 37 times better at destroying the genes than graphitic carbon nitride alone.

The work done under the auspices of the Rice-based Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT) is detailed in the American Chemical Society journal Environmental Science and Technology.

"This study addresses a growing concern, the emergence of multidrug resistant bacteria known as superbugs," said Alvarez, director of the NEWT Center. "They are projected to cause 10 million annual deaths by 2050.

"As an environmental engineer, I worry that some water infrastructure may harbor superbugs," he said. "For example, a wastewater treatment plant in Tianjin that we've studied is a breeding ground, discharging five NDM1-positive strains for each one coming in. The aeration tank is like a luxury hotel where all bacteria grow.

"Unfortunately, some superbugs resist chlorination, and resistant bacteria that die release extracellular ARGs that get stabilized by clay in receiving environments and transform indigenous bacteria, becoming resistome reservoirs. This underscores the need for technological innovation, to prevent the discharge of extracellular ARGs.

"In this paper, we discuss a trap-and-zap strategy to destroy extracellular ARGs. Our strategy is to use molecularly imprinted coatings that enhance selectivity and minimize interference by background organic compounds."

Molecular imprinting is like making a lock that attracts a key, not unlike natural enzymes with binding sites that only fit molecules of the right shape. For this project, graphitic carbon nitride molecules are the lock, or photocatalyst, customized to absorb and then destroy NDM1.

To make the catalyst, the researchers first coated the nanosheet edges with a polymer, methacrylic acid, and embedded guanine. "Guanine is the most readily oxidized DNA base," Alvarez said. "The guanine is then washed with hydrochloric acid, which leaves behind its imprint. This serves as a selective adsorption site for environmental DNA (eDNA)."

Rice graduate student Danning Zhang, co-lead author of the paper, said carbon nitride was chosen for the base nanosheets because it is nonmetallic and is thus safer to use, and for its easy availability.

Alvarez noted all catalysts are efficient at removing ARGs from distilled water, but not nearly as effective in secondary effluent, a product of sewage treatment plants after solids and organic compounds are removed.

"In secondary effluent, you have reactive oxygen species scavengers and other inhibitory compounds," Alvarez said. "This trap-and-zap strategy significantly enhances removal of the eDNA gene, clearly outperforming commercial photocatalysts."

The researchers wrote that conventional disinfection processes used at wastewater treatment plants, including chlorination and ultraviolet radiation, are moderately effective in removing antibiotic-resistant bacteria but relatively ineffective at removing ARGs.

They hope their strategy can be adapted on an industrial scale.

Zhang said the lab has not yet run extensive tests on other ARGs. "Since guanine is a common constituent of DNA, and thus ARGs, this approach should also efficiently degrade other eARGs," he said.

There is room to improve the current process, despite its extraordinary initial success. "We have not yet attempted to optimize the photocatalytic material or the treatment process," Zhang said. "Our objective is to offer proof-of-concept that molecular imprinting can enhance the selectivity and efficacy of photocatalytic processes to target eARGs."

Qingbin Yuan of Nanjing Tech University, China, is co-lead author of the paper. Co-authors are Rice graduate students Ruonan Sun and Hassan Javed, and Gang Wu, an assistant professor of hematology at The University of Texas Health Science Center at Houston's McGovern Medical School. Pingfeng Yu, a postdoctoral researcher at Rice, is co-corresponding author. Alvarez is the George R. Brown Professor of Civil and Environmental Engineering and a professor of chemistry and of chemical and biomolecular engineering.

The membrane surrounding cells acts as a selective barrier, cradling and protecting the cell's contents from the external surroundings and choosing which substances to allow in or out of the cell. Scientists have therefore struggled to engineer efficient methods of delivering nanomaterials, such as DNA, proteins and drugs, into cells.

Now, researchers from Korea University, in collaboration with the Okinawa Institute of Science and Technology Graduate University (OIST), have developed a rapid and efficient delivery method that uses the power of a tiny fluid vortex to deform the cell membranes. Their findings were recently published in the journal, ACS Nano.

"Current methods suffer from numerous limitations, including issues with scalability, cost, low efficiency and cytotoxicity," said Professor Aram Chung from the School of Biomedical Engineering at Korea University, who led the study. "Our aim was to use microfluidics, where we exploited the behavior of tiny currents of water, to develop a powerful new solution for intracellular delivery."

The new device - a microfluidic chip called a 'spiral hydroporator' - can deliver nanomaterials into around one million cells each minute, with up to 96% efficiency. Moreover, the entire process is achieved without irreversibly damaging the cells, with up to 94% of the cells surviving the process.

"The chips are really affordable to make and simple to use," said Professor Chung. "You just pump a fluid containing the cells and nanomaterials in two ends, and the cells - now containing the nanomaterial - flow out of the other two ends. The entire process takes only one minute."

Going with the flow

To create the device, the scientists designed the channels in the microfluidic chip in a specific configuration, with a cross-junction at the center of the chip and two T-junctions above and below.

When the scientists from Korea University first studied how different channel geometries and flow rates affected the cells, one specific scenario - a cross-junction where moderately flowing streams of fluid collided from opposite directions - stood out as peculiar.

"We saw a really interesting behavior exhibited by the cells, where they danced around in the center of the cross-channel," said Professor Chung.

By adding a fluorescent dye into one of the fluid streams, the researchers discovered that a spiral vortex had formed.

"We wanted to fully understand the fluid mechanics causing this effect, and the Micro/Bio/Nanofluids Unit led by Professor Amy Shen at OIST was already working on the problem," Professor Chung added.

The two groups of scientists therefore teamed up. Using the OIST supercomputer, the OIST unit developed and ran simulations of how the opposing fluid streams interacted at the cross-junction, at different rates of flow.

"At a low flow rate, we found that the two impinging streams of fluid parted symmetrically and flowed away from the cross-junction, as documented in the literature," said OIST scientist, Dr. Simon Haward. "However, as we increased the flow rate, we saw instabilities arise which caused multiple vortices to form, eventually merging into one large spiral vortex."

"Our simulation explained the unusual phenomena that Chung's group had observed and showed exactly how certain parameters, such as flow rate, affected vortex formation," added OIST postdoctoral researcher, Dr. Daniel Carlson.

The formation of the vortex is key to the rapid and effective delivery of nanomaterials into the cells. As each cell passes into the center of the cross-junction, the force of the spiral vortex deforms the cell, causing tiny nanoholes to arise in the membrane. The nanomaterials in the fluid are then able to move into the cell through these nanoholes. The cells are then swept away from the cross-junction and collide with the walls of the T-junctions, which causes further deformation of the cell membrane and increases the efficiency of delivery. After deformation, the nanoholes in the membrane reseal themselves and the membrane is repaired.

Boosting cell biology research

Using spiral hydroporation, the team at Korea University were able to deliver specific nanomaterials into cells, including RNA and gold nanoparticles.

More efficient and low-cost delivery of DNA, RNA and proteins such as CRISPR-Cas9 into large numbers of cells could assist research into topics including gene therapy, cancer immunotherapy and stem cells, Chung said.

Gold nanoparticles can also be used for delivering drugs, imaging molecules and organelles within cells, and for diagnosing disease.

"Overall, there are a vast array of applications for spiral hydroporation and interest in the chip has been very high," said Professor Chung. "Researchers need a more efficient, simple, rapid and low-cost means of intracellular delivery - our chip is a great new avenue for achieving that goal."

"Rock-chair" Li-ion battery (LIB) was discovered in the late 1970s and commercialized in 1991 by Sony, which has become the priority way we store portable energy today. To honor the contribution for "creating a rechargeable world", the 2019 Nobel Prize in chemistry was awarded to three famous scientists (John B. Goodenough, M. Stanley Whittingham, Akira Yoshino) who made the most important contributions to the discovery of LIBs. However, this technology is nearing its practical performance limits and extensive efforts are underway to replace LIBs with new electrochemical storage solutions, which are safe, stable, low cost and with higher energy density to power long-range electric vehicles and long-lasting portable electronics.

Replacing the traditional graphite-based anodes with Li metal, a "holy" anode with a high theoretical capacity of 3860 mAh/g, shows it a promising approach. At present, Li metal anode suffers from poor cycling efficiency and infinite volume change, raising operational safety concerns. Effective efforts include functional electrolyte additive, artificial solid-electrolyte interface and using host scaffolds to buffer the volume expansion have been taken to tackle its disadvantages. Among these, the method of using scaffolds continues to see rapid development.

Graphite, a classic Li anode, shows a great promising as an effective host scaffold, which possesses a low density and high electron conductivity. However, it is generally accepted that Li metal wets graphite poorly, causing its spreading and infiltration difficult. Previous methods to transforming graphite from lithiophobicity to lithiophilicity include surface coating with Si, Ag or metal oxide (lithiophobic indicates a large contact angle, while lithiophilic indicates a low contact angle between molten lithium and solid surface). However, such a change in liquid spreading behavior is due to the replacement of graphite by reactive coating. Consequently, it might be asked whether graphite is intrinsically lithiophobic or lithiophilic.

Herein, the wetting behavior of molten Li on different kinds of graphite-based carbon materials were systematically studied. Firstly, the highly oriented pyrolytic graphite (HOPG) was used as the test sample (Figure a). It is observed that HOPG substrate immediately allows an contact angle (CA) of 73° with Li metal (Figure b, c). To check this experiment against theory, ab initio molecular dynamics simulation was performed with a molten Li droplet (54 Li atoms)/graphite (432 C atoms, two-layered graphene) setup to prove that a clean (002) surface of graphite is intrinsically lithiophilic at 500K and the results also confirmed that lithium and graphite have good affinity.

However, the CA of Li metal on porous carbon paper (PCP, Figure d) is as high as 142°, which indicates PCP is lithiophobic (Figure e and f). This result which contradicted with previous conclusion that graphite is intrinsically lithiophilic prompted researchers to gain further understanding of the effect of surface chemistry to the wetting performance of Li metal and graphite. Compared with HOPG, it is found that PCP surface has a large number of oxygen-containing functional groups. These surface impurities will play a key role in pinning the contact line between Li metal and PCP, resulting in a lager apparent contact angle.

In order to demonstrate this assumption, the PCP was first lithiated by decreasing its electrochemical potential with molten Li metal (Figure g). During this process, the surface impurities of PCP will be eliminated as well. The following experiment shows that lithiated PCP exhibited a small CA of ~52°, which indicated a successful transition from lithiophobicity to lithiophilicity. Due to its porous structure of lithiated PCP, the Li metal rapid diffused through (Figure h and i). The DFT simulation revealed that lithiated graphite and graphite possessed similar wetting performance, demonstrating the elimination of the surface impurities would be the key reason for this transition of wetting performance from PCP to lithiated PCP. The graphite powder is further used to test its wettability with Li metal. After continue mixing, the graphite powder could be uniformly dispersed in the Li metal matrix, further confirming a lithiophilic property of graphite. Taking advantage of this discovery, a novel Li metal-graphite compositing method was proposed and Li-graphite composite anode with large area can be produced in a large scale.

This work not only systematically studies the wettability of Li metal and graphite-based carbon materials, but also provides a novel idea for the construction of Li-carbon composite anode materials, which is helpful for the development of high-energy Li metal batteries.

Researchers at the Netherlands Institute for Neuroscience (NIN) have shown that specialized aggregates of molecules enwrapping nerve cells in the brain, the perineuronal nets, are crucial for regulating the connections between nerve cells that control motor memories. The discovery, published in the Proceedings of the National Academy of Sciences (PNAS), provide novel insight into how memories are formed and stored in the brain.

PERINEURONAL NETS INFLUENCE LEARNING

As the brain becomes older, the contacts between nerve cells (synapses) become less flexible, because they are encased in a meshwork of proteins and carbohydrates called a perineuronal net. In the current study, researchers of the NIN (Verhaagen group and De Zeeuw group), in collaboration with the University of Turin and the University of Cambridge, induced a remarkable remodeling of cerebral synapses. They improved the learning abilities of mice by using a powerful molecular tool to degrade the perineuronal nets. However, the capability of the mice to remember what they had learned was disturbed, indicating that the storage of acquired information requires intact perineuronal nets. "This is the first time that it has been shown that changes in perineuronal nets are instrumental for motor learning and memory", says Daniela Carulli, researcher at the NIN and first author of this study.

CHANGING OF PERINEURONAL NETS

Children have the capability to learn much better than adults, from mastering a new language to playing a musical instrument. This is possible thanks to the flexibility (or "plasticity") of the connections between nerve cells in young brains. Plasticity also allows a faster recovery from brain injury. "We discovered that perineuronal nets exert tight control on learning and memory in the adult brain", explains Carulli. The researchers investigated a well-characterized type of learning, called eyeblink conditioning, that depends on the cerebellum, a brain region involved in motor functions. "Our results indicate that perineuronal nets are diminished during the learning phase of eyeblink conditioning, but are restored at later stages, when memories are consolidated", Carulli continues.

Much still needs to be known as to how exactly perineuronal nets regulate plasticity, and, thereby cognitive functions. This is crucial in view of finding therapeutic strategies to tackle cognitive decline in the elderly or in patients with neurological disorders.

Wild, treeless landscapes are becoming more wooded as climate change leads to warming temperatures and wetter weather, research suggests.

Trees and shrubs are spreading across the tundra and the savanna, transforming these vast, open areas that contain unique biodiversity, researchers say.

The dramatic changes to these regions - which account for some 40 per cent of the world's land - could alter the global carbon balance and climate system, scientists say. This is because woody plants store carbon, provide fuel for fires and influence how much of the sun's heat is reflected back into space.

As well as affecting the climate, increasing woody plant cover could alter the unique biodiversity of areas home to diverse species including caribou in the tundra and elephants in the savanna, researchers say.

Rapid warming in the Arctic tundra - spanning northern parts of Canada, the US, Greenland, northern Europe and Russia - has increased shrub plant cover there by 20 per cent over the past 50 years, the study found.

Expanding shrub cover could raise soil temperatures in the tundra, leading to thawing of the permafrost - frozen ground that contains nearly half of the world's soil carbon.

Scientists found that shrub and tree cover in savannas - which include Africa's plains, Australia's outback and drylands of South America - rose by 30 per cent during the same period, as rainfall increased.

A team led by University of Edinburgh researchers carried out the largest global woody cover change study of its kind to date. They compared temperature and rainfall data with more than 1000 records of plant cover change from almost 900 sites across six continents.

They also found that other factors - including wild fires and animal grazing patterns - affect shrub and tree cover, revealing that variables shaping the future of the tundra and the savanna are more complex than previously thought.

The study, published in the journal Global Ecology and Biogeography, was funded by the Natural Environment Research Council and the University of Edinburgh.

Mariana García Criado, of the University of Edinburgh's School of GeoSciences, who led the study, said: "This research indicates the far-reaching effects of climate change across the planet. Uncovering the ways in which different landscapes are responding requires collaboration among scientists, and cooperation with local peoples to better understand the changes we're seeing and their impacts from different perspectives."

Researchers of Sechenov University together with their colleagues from Australia used the microfluidics technology to develop a device able to isolate cancer cells from urine of patients with prostate cancer. The study showed high sensitivity and specificity of the new method in diagnosing prostate cancer. The results obtained were published in Cancers.

Prostate cancer is the second most common type of cancer among men: in 2018 about 1.27 million new cases were registered, almost 360,000 patients died. It's not easy to gain a significant decrease of mortality rate because there is no practical or accurate enough method of diagnosis able to detect the disease in its early stage.

Nowadays two methods are usually used to prove the diagnosis: the prostate-speci?c antigen (PSA) blood test and the tissue biopsy - taking the tissue samples for analysis. Both of these methods have significant drawbacks. Blood test is not speci?c enough and can produce false positive results since the PSA level rises not only in case of prostate cancer but also during other diseases of the prostate gland. Tissue biopsy is an invasive examination that can cause adverse side e?ects such as local bleeding and infections. Also, as previous studies have shown, the sensitivity of liquid blood biopsy (isolating cancer cells) is rather poor because of the low level of the cells in blood. So, scientists suggest an alternative that is a liquid urine biopsy: the prostate gland is closely connected with the urethra and cancer cells are washed out during urination.

"As we have shown, while testing this technique we managed to collect 85 (±6) % of the total number of prostate cancer cells as well as to isolate cells from the urine of 86% of patients with localised cancer in the early stage. Now we are trying to optimise the method to improve its efficacy, specificity and sensitivity while the technology itself is going through the patent process," said Alexey Rzhevskiy, research associate in the Institute of Molecular Medicine, Sechenov University.

To isolate cells from the liquid, researchers developed a micro?uidic chip - a device made from polymer with a thin spiral channel, forked on one end, and three holes: one for urine intake and two for cell separation. The chip is so designed that cancer cells which are larger than others shift to the inner wall of the channel and leave it through one of the holes while smaller and lighter cells gather along the outer wall and come out through the other hole. This effect is caused by the joint action of several centrifugal forces.

Scientists labelled the collected cells with ?uorescent antibodies - molecules able to glow while absorbing light of a certain wavelength. Researchers examined cancer cells with the antibodies under a fuorescence microscope and measured the intensity of the light emitted: if it exceeded the calculated threshold, scientists concluded that these cells were cancerous.

The authors tested the device using saline with the known number of cells (in pilot studies) and the samples of urine of healthy volunteers and patients with the prostate cancer. During the pilot experiments the chip isolated from 80 to 90% of cancer cells. Tests with the urine samples were rather successful too: they detected the disease in 12 out of 14 patients with cancer and confirmed the health of 11 out of 14 healthy volunteers.

Bone marrow plasma cells produce antibodies. These comprise two long and two short protein chains. The pathological proliferation of plasma cells can lead to an overproduction of the short chains. These associate to fibrils and deposit in organs. The result is fatal organ failure. A research team from the Technical University of Munich (TUM) and Heidelberg University has now identified the mutation behind the disease in a patient.

Antibodies are vital for the survival of human beings. They typically consist of two longer and thus heavier amino acid chains and two lighter ones. In rare cases, the plasma cells multiply excessively, flooding the body with light antibody chains.

In people suffering from light chain amyloidosis (AL amyloidosis), these light chains are deposited as extremely fine fibers, so-called amyloid fibrils, in tissue or in organs. The disease is often recognized only after the deposits already compromise the function of organs. In many cases AL amyloidosis is fatal.

"To date, little was known about the exact cause of this amyloidosis," says Johannes Buchner, professor of biotechnology at the Technical University of Munich. "Depending on the organ affected, the symptoms vary considerably. Furthermore, each patient produces different types of antibodies. The disease is thus difficult to diagnose at an early stage."

A mutation triggers the deadly disease

Using various analytical and database-supported methods, the team of scientists succeeded in identifying eleven mutations caused by the disease in the antibodies of a patient with advanced AL amyloidosis.

Further investigations showed that exactly one mutation was responsible for the destabilization and formation of the disease-causing amyloid fibrils. This mutation causes the unstable light chain to lose its structure after breaking into fragments, which then form the deadly amyloid fibrils.

"Our study shows that mutations that lead to unstable light chains are an important factor in the occurrence of amyloidosis," says Pamina Kazman, who carried out the majority of the measurements. "In the long term, we hope that these and other studies will lead to new, earlier diagnostic methods and possibly even new treatment options."

Many surveys of American adults have revealed that they worry about political issues and are concerned for the future of the United States. But what about children and teenagers?

A new psychological study, published in the journal Child Psychiatry and Human Development, is believed to be the first to examine youths' worry about political issues, and it suggests that children and teens are worried too. The study also found that the worries experienced by children and teenagers reflect many sides of a political issue; the findings pertain to youth across the political spectrum. It's unclear that children's and teens' worry is a cause for concern, or that it is interfering with their mental health functioning.

Typically, worry about political issues has not been on psychologists' radars when assessing mental health. Since the 2016 presidential election in the United States, however, Americans' anxiety about political issues have come into focus. More adults are reporting to therapists feelings of anxiety about political issues, and even before the 2016 contest, the American Psychological Association surveyed Americans and found political issues to be a "significant source of stress" for both Republicans and Democrats.

Until now, there has been little, if any, attention paid to youths' worry about political issues. Realizing this, American University Assistant Professor of Psychology Nicole Caporino devised a psychological measure to gauge how frequently youth are worrying, if at all, and which political issues they are worrying about most. A child clinical psychologist who specializes in child anxiety and obsessive-compulsive disorder, Caporino leads the Clinic for Youth Anxiety and Related Disorders at AU. The clinic provides assessment and therapy for children and adolescents ages 4 through 17 years old. Caporino supervises a staff of clinical psychology doctoral students who work with the youth and provide these services.

Over time, Caporino has seen her young patients express worry about political issues, from the possibility of deportation (regardless of citizenship status), to peers being bullied or victimized due to Muslim worship, to the possibility of being "kidnapped" by a political party and separated from family.

"I was interested in finding out if worry about political issues extends to kids beyond those with anxiety disorders," she said. "It turns out that it does. In our study, it was common for caregivers to report that their children have worried about political issues. However, it's not clear from these data that the worry experienced by the average kid is harmful. It may not be a problem that kids are worrying. We know that anxiety and worry, to a certain degree, are helpful because they motivate us to take action to improve what is troubling us."

The study surveyed caregivers of children and teenagers from across the United States. More than 370 caregivers of youth 6 to 17 years old participated. Caregivers identified as independents, Republicans or Democrats. Selecting from a number of worries related to 15 voting issues, caregivers rated the frequency of their child's anxiety. For the majority of voting issues, more than half of caregivers indicated that their child experienced at least one relevant worry. Worries about the environment and gun violence were most common, followed by worry related to the economy, treatment of racial/ethnic minorities, foreign policy and terrorism.

While the study found that both caregivers who self-identified as Republicans and Democrats reported worry, the caregivers of Republicans reported that their children experienced more frequent worry about political issues.

"Youth are worrying about a wide range of issues, and especially those that disproportionately affect their generation," Caporino said. "Although this worry is not frequent, on average, it appears to be widespread, regardless of caregivers' political party affiliation."

About a quarter of the caregivers surveyed indicated that their child had clinical levels of anxiety. Based on Caporino's analysis, these youth have significantly greater worry about political issues and may be at greater risk for harmful mental health effects from following the news. This was not surprising, Caporino said. One of the hallmarks of generalized anxiety disorder, or GAD, is frequent worry about many issues or events. Nonetheless, it should signal to parents of children with anxiety disorders that worry about political issues could be an additional stressor.

Therapists will want to take this into consideration and assess for worry about political issues in clinical settings, so that they can help youth manage any worry that is excessive.

For children and youth, generally, Caporino recommends that caregivers talk to their children.

"Talk to your kids to make sure that the information they're getting is accurate, and that they're not worrying unnecessarily because they're making assumptions about political issues they don't understand very well due to their developmental level," Caporino said.

Future studies should survey diverse samples of youth directly about their anxiety about political issues. Studies should also identify strategies for mitigating the negative impact of political news on youth with anxiety disorders.

Sometimes in a glass of wine, liquid can appear to climb the side of the glass, forming "tears" that slide back down into the wine. Now, researchers have created a new hydrodynamic model to better account for wine tears' fluid dynamics. The model shows that a combination of fluid physics, including gravity, surface tension, and changes in surface tension induced by alcohol evaporation, can lead to complex fluid structures resulting in wine tears.

Theory for undercompressive shocks in tears of wine

by Yonatan Dukler, Hangjie Ji, Claudia Falcon, and Andrea L. Bertozzi

A team of researchers from the University of Georgia and San Diego State University has found that the practice of feeding wildlife could be more detrimental to animals than previously thought.

In a paper published recently in Nature Scientific Reports, researchers found that feeding wildlife can disrupt the social lives of animal communities, which they discovered by observing and documenting the behavior of moor macaque monkeys along a wooded roadway on the island of Sulawesi in eastern Indonesia.

Monkeys gather along this heavily traveled roadway to accept food from passing motorists, and the researchers wanted to know what factors made some monkeys more inclined to interact with humans and how those interactions affected the group as a whole.

In particular, the researchers wanted to know whether social relationships influenced the amount of time some monkeys spent along the road and how traits like age and sex contributed to those decisions.

"It's a bit like the old saying that goes, 'If your friends jumped off a cliff, would you do it too?'" said Kristen Morrow, a doctoral student in anthropology at UGA and lead author of the study. "Yes, there is a food reward associated with humans, but this is risky behavior, and wild monkeys like these are generally very cautious around humans. So, we wanted to know how this behavior impacts their community."

In general, the researchers found that male macaques were more likely to take the risk of approaching humans, who commonly offered the monkeys bread, fruit, potato chips and other processed foods.

They also found that macaques who have greater influence within the community of monkeys would visit the roadside more frequently.

While this regular proximity to humans may have resulted in a food reward, it also disrupted normal social behaviors that are typical of these macaques in the forest farther away from humans.

"When the monkeys were along the road there were fewer social connections between individuals. This change can reduce the opportunities for positive interactions, such as grooming one another or resting nearby one another," Morrow said. "These are important behaviors, because they serve as a foundation for social learning and relationship building that lead to a strong, cohesive community."

Disruption of these social bonds could be detrimental to the monkeys' health, life span, reproductive success and infant survival, according to the study.

In total, the macaques spent about 20% of their time along the road and 80% in the forest. But their behavior along the road was often in stark contrast to their behaviors in the forest, where they spend most of their time foraging for wild fruit away from the noise and distractions of the busy roadway.

Over time, it's possible that these regular interactions with humans could fundamentally change the social structures of this and other communities of monkeys, Morrow said.

This is important information to have as people try to address conservation issues related to loss of habitat or where animals are more likely to interact with humans, Morrow said.

"Our results suggest that moor macaques are attracted to the road because they perceive that the benefit of receiving food provisions outweighs any risks associated with being in close proximity to people and moving vehicles," said Erin Riley, professor of anthropology at San Diego State University and the senior author on the paper. "This finding suggests that a macaque-focused approach to managing this interface may be ineffective. Instead, efforts are likely better focused on changing people's behavior by expanding their knowledge of the negative effects of feeding the macaques and why protecting them is important."

The researchers collected their data six hours per day, six days a week from August 2016 to January 2017. Every 30 minutes, the researchers would scan the group and record each individual macaque's location and their behaviors, which could include rest, feeding, play or aggression.

They followed the study group for about 565 hours, during which they completed more than 1,200 scan samples of the monkeys.

"While this study tells us a lot about the potential impacts of human interactions with this community of macaques, we need to do more research to understand how these behaviors affect wildlife," Morrow said. "Humans and animals are crossing paths more frequently, and we need to understand the effects of these interactions to build effective conservation practices."

Researchers at UC have discovered a previously unknown mechanism that could explain the reason behind decreased immune function in cancer patients and could be a new therapeutic target for immunotherapy for those with head and neck cancers.

The authors share these findings in an article published in the journal Frontiers in Pharmacology.

Immunotherapy is a type of cancer treatment that boosts the body's natural defenses to fight cancer.

Led by Laura Conforti, professor in the Department of Nephrology and Hypertension at the UC College of Medicine, the team discovered that a reduced interaction between a molecule called calmodulin and an ion channel (KCa3.1) in the immune cells of cancer patients plays an important role in the reduced function of these cells. The team performed experiments on white blood cells called cytotoxic T-cells taken from the blood of patients with head and neck cancer.

"Cytotoxic T-cells are like the soldiers of our immune system and are our body's first line of defense against cancerous tumors," says first author Ameet Chimote, research scientist in Conforti's laboratory. "Just like how soldiers on the frontlines penetrate the enemy's defense and launch a massive attack, these cytotoxic T-cells are expected to penetrate the solid tumors by migrating within the tumor mass and then secreting chemicals called cytokines to kill these tumor cells. Sadly, for some reason, these cells do not function properly in patients with cancer, and they do not penetrate the tumors and attack the tumor cells, causing the cancerous tumors to grow uncontrollably."

"Identifying the mechanism of this underlying dysfunction can help us identify molecules that we can target with drugs and ultimately restore the ability of these cells to enter and kill the tumors," says Conforti. She says that molecules, known as ion channels, are present in the T-cell membranes and are essential for T-cell function.

"In this study, we were able to show that the function of these channels in T-cells from cancer patients is decreased which results in a decreased T-cell accumulation in solid tumors," Conforti says.

These types of channels require a signaling molecule called calmodulin to bind to them in order to function to their full capacity; this is needed even more in cancer T-cells.

Using several intricate microscopy imaging techniques on T-cells isolated from the blood of cancer patients, the team found out that, as compared to T-cells from healthy individuals, the cancer T-cells have fewer calmodulin molecules in their membranes.

"This would mean that there is less calmodulin binding to the channels in the T-cells from cancer patients," Conforti says. "As previously stated, the channels do not function if the calmodulin does not bind to them. Thus, the decreased calmodulin binding in T-cells from cancer patients results in decreased function and leads to reduced tumor infiltration and killing of the cancer cells."

"So back to our soldiers: If they were present at a battlefield, but none of them have any weaponry, this will hinder their ability to infiltrate the enemy lines. Now, if we arm each soldier adequately, we would boost their function. They can do their job. Similarly, we observed that if we increase the function of these channels by drugs that enhance their activity, the cancer patients' T-cells can penetrate the tumors better and also produce increased cytokines which can kill tumor cells," Chimote says. "These are exciting findings that could lead to additional treatments for patients with cancer."

"These findings strengthen the therapeutic potentials of [these] activators, which could restore cytotoxic T-cell functionality and can ultimately lead to additional immunotherapeutic options for patients with cancer," Conforti adds.

The natural coastal defenses provided by mangrove forests reduce annual flooding significantly in critical hotspots around the world. Without mangroves, flood damages would increase by more than $65 billion annually, and 15 million more people would be flooded, according to a new study published March 10 in Scientific Reports.

"Mangroves provide incredibly effective natural defenses, reducing flood risk and damages," said Pelayo Menéndez, a postdoctoral fellow in the Institute of Marine Sciences at UC Santa Cruz and first author of the paper.

Climate change is increasing the risk of coastal flooding through its effects on sea level rise and the intensity of hurricanes. According to the study's authors, conservation and restoration of natural defenses such as mangroves offers cost-effective ways to mitigate and adapt to these changes.

The researchers provided high-resolution estimates of the economic value of mangrove forests for flood risk reduction across more than 700,000 kilometers of coastlines worldwide. They combined engineering and economic models to provide the best analyses of coastal flood risk and mangrove benefits. Their results show when, where, and how mangroves reduce flooding, and they identified innovative ways to fund mangrove protection using economic incentives, insurance, and climate risk financing.

"Now that we can value these flood protection benefits, it opens all kinds of new opportunities to fund mangrove conservation and restoration with savings for insurance premiums, storm rebuilding, climate adaptation, and community development," said coauthor Michael Beck, research professor in the Institute of Marine Sciences at UC Santa Cruz.

Mangrove forests occur in more than 100 countries globally. But many mangroves have been lost to aquaculture and coastal development, including the construction of public infrastructure such as ports and airports. In the early 1900s, vast areas of mangroves were filled throughout Florida, and whole developments were created where there once were islands and mangrove forests.

The loss of mangrove forests leads to increased coastal flooding, but these forests can be easily restored to make people and property safer, Beck said. Mangroves are resilient, and scientists know how to restore them--projects across Vietnam, Philippines, and Guyana have restored 100,000 hectares of mangroves.

"Mangroves are resilient and can grow like weeds, even around cities, if we give them half a chance," Beck said.

The new study rigorously valued the social and economic coastal protection benefits provided by mangroves globally. Many 20-kilometer coastal stretches, particularly those near cities, receive more than $250 million annually in flood protection benefits from mangroves.

The researchers are working with insurance companies, the World Bank, and conservation groups to use these results for risk reduction and conservation.

The study used the "expected damage function" approach, commonly used in engineering and insurance sectors to assess flooding. Hydrodynamic models were used to calculate the flooding that occurs globally under current and no-mangrove scenarios. By identifying the places where mangroves provide the greatest flood reduction benefits, this study informs policies for adaptation, sustainable development, and environmental restoration.

"We have combined rigorous tools from engineering and economics to show that mangroves really work for flood risk reduction," said coauthor Íñigo Losada, chief scientist at IH Cantabria.

With the spread of electric vehicles, interest in "high capacity batteries" is high. Lithium metal batteries, which use lithium metal on their anodes, are also drawing attention in this context. However, the problem is that the stability of the lithium metal is too large and the stability is low. The technology that solved this by the "electrolyte" in battery came out.

A joint research team, led by Professor Nam-Soon Choi and Professor Sang Kyu Kwak in the School of Energy and Chemical Engineering at UNIST has developed an ion concentrate electrolyte using a solvent containing fluorine atoms. The electrolyte evenly formed a protective film on the negative electrode and the positive electrode of the lithium metal battery, increasing the lifespan and output of the entire battery.

The charging and discharging of a lithium metal battery or a lithium ion battery occurs when a lithium ion moves between a positive electrode and a negative electrode. At this time, the passage through which lithium ions pass is the 'electrolyte', and the electrolyte itself reacts on the surface of the electrode (cathode / anode) to form a protective film. However, when this protective film is formed nonuniformly, a problem arises. Lithium metal sharply rises on the negative electrode, causing a short circuit, or modifying the positive electrode to reduce battery performance. Therefore, it is important to make an ideal type of protective film, and the electrolyte components must be effectively controlled for this purpose.

Professor Nam's research team developed a new composition containing fluorine (F) to protect both the negative and positive electrodes at the same time and increase the battery output. Fluorine reacted with lithium to form a protective film on the surface of the lithium electrode, and also repaired when the protective film was partially destroyed.

"The fluorine-containing electrolyte formed a protective film on the anode, and the electrolyte was decomposed at a high voltage of 4V or more and the adhesion to the anode was solved," says Yongwon Lee (Department of Energy Engineering at UNIST), a senior researcher at the R&D center of LG Chemical Co., Ltd. "This allows the implementation of high-voltage, long-life lithium metal batteries that was not available in the electrolytes of conventional lithium-ion batteries."

Professor Kwak's team used theoretical calculations to identify reaction trends and reaction mechanisms for fluorine-containing solvents. In particular, the fluorinated ether solvent, which has a reduction reaction more easily than conventional fluorine, has a property of easily emitting fluorine, thereby promoting the formation of a protective film (fluorinated interface) on the cathode. Kwak said, "This calculation principle will contribute to the development of functional electrolyte materials and additives for the high performance of lithium metal batteries."

"The electrode interfacial stabilization mechanism will be used to design the electrolyte system for high energy density cell development," says Professor Kwak. "It is expected to be of great help in improving the electrochemical performance of next generation high energy density batteries, including lithium ion batteries using the same positive electrode as lithium metal batteries."