Tech

Materials called perovskites can be more readily incorporated into silicon-based semiconducting platforms by using a microfluidic pumping technology developed at KAUST.

The perovskites currently being explored for many applications in new technologies are diverse materials sharing the same crystalline structure as the natural mineral perovskite. These semiconducting materials show great promise in a variety of optoelectronic applications, such as light emitters, sensors and solar cells.

Compared to traditional semiconductors, perovskites are soft and unstable. "This makes it difficult to pattern them using standard lithography methods," says materials scientist Iman Roqan at KAUST.

The challenge tackled by Roqan and her colleagues was to adapt microfluidic technologies to manipulate solutions carrying perovskites to create semiconducting microscale wires.

The first step in the procedure is to create the desired pattern of microchannels in a silicon wafer using a laser interference technique. The key innovation is to pump a solution containing perovskite ions into these microchannels, where the perovskite solidifies into the network of semiconductor wires.

"We are the first researchers to achieve this," says Roqan, adding that the innovation, which has now been patented, will allow several different perovskite-based optoelectronic devices to be located on one silicon chip. For example, a single chip could embody a photodetector, transistor, light-emitting diode and a solar cell to act as the power supply.

To demonstrate the potential of the technique, the team have built a high-performance photodetector.

"Unlike other options, our fabrication method is extremely simple and cost-effective, while avoiding creating waste materials," Roqan says. Some metals used in perovskites are toxic, so avoiding their release into the environment is a significant advantage.

There remain challenges to overcome to advance from this initial proof-of-concept stage. For example, the team is working to bring the stability of the devices up to a standard suitable for large-scale industrial applications. Roqan expects that work currently in progress to achieve this is likely to lead to further patents, while also building more complex demonstration devices.

One of the most likely areas for commercial development is in the growing field of "lab on a chip" technology. This can combine processes such as sensing, signaling, microfluid manipulation and chemical separations and combinations to miniaturize many laboratory procedures used in medicine and biology. With miniaturization comes portability, potentially taking a full testing laboratory process out of the lab and into the outside world.

Results of a 2018 multirocket launch at Poker Flat Research Range north of Fairbanks, Alaska, will help scientists better understand the impact of more water vapor accumulating near the fringe of the Earth's atmosphere.

"This is the first time anyone has experimentally demonstrated that cloud formation in the mesosphere is directly linked to cooling by water vapor itself," said Irfan Azeem, space physicist at Astra LLC in Louisville, Colorado, and principal investigator of the Super Soaker mission.

The NASA-funded project, named Super Soaker, involved launching a canister containing about 50 gallons of water skyward to create an artificial polar mesospheric cloud on the night of Jan. 25-26, 2018. A ground-based laser radar (lidar) detected the cloud that formed 18 seconds after the water release 50 miles overhead.

A time-lapse photograph captures the Super Soaker launches on Jan. 25-26, 2018. Three rockets launched with the mission, two using vapor tracers to track wind movement and one releasing a water canister to seed a polar mesospheric cloud. The green laser beam visible at the top left is the LIDAR beam used to measure the artificial cloud.

Findings of the Super Soaker experiment were published this month in the Journal of Geophysical Research in a paper authored by Richard Collins, director of the University of Alaska Fairbanks Graduate School and a professor of atmospheric sciences at the Geophysical Institute, with Azeem and a team of scientists from across the United States. Geophysical Institute graduate students Jintai Li and Jennifer Alspach, who developed lidar systems for the project and participated in the experiment, were among the paper's 10 co-authors. Undergraduate student Mikayla Grunin worked with Li to develop one of the lidar systems.

The Super Soaker experiment showed that water vapor contributes to cloud formation in the upper atmosphere in two ways: by making the air more humid and by cooling the air. This moisture-driven cooling is distinct from the "greenhouse effect" warming that water vapor causes in the lowest level of the atmosphere -- the troposphere.

Increased water vapor comes from methane, which is being produced by humans in rising quantities. Methane rises into the mesosphere, where it oxidizes in sunlight to form water vapor and carbon dioxide.

Space traffic also adds to the amount of water vapor collecting in this region of the atmosphere, as water vapor is common in rocket engine exhaust, the paper notes. Increases in space traffic will result in more water being deposited in the upper atmosphere.

What are the implications of this cooling of the upper atmosphere?

"We expect that a more humid atmosphere should be cloudier, just as we see fog form over ponds on cold mornings. What we found that is new is that the water vapor appears to actively cool the atmosphere to promote cloud formation," Collins said.

"We don't believe it's going to cause a radical effect at the ground, but it helps us understand long-term climate trends in the atmosphere and the role of water vapor in the climate system," he said. "And it also allows us to understand better our weather and climate models, where a lot of times cloud formation is the acid test of whether all the parts of your weather and climate model are working."

Polar mesospheric clouds exist at the edge of space at an altitude of 47 to 53 miles. Water vapor at these altitudes freezes into ice crystals, forming the clouds. These clouds can be seen as they glow brightly after sunset when they are lit from below by sunlight against a dark sky. Polar mesospheric clouds are also called night-glowing or noctilucent clouds.

The clouds appear naturally in the Arctic or Antarctic during summer. Researchers chose to create the artificial cloud in the winter to have a controlled setting.

These clouds have long been used as indicators of climate change. First reported in the late 1800s, the clouds have been seen more often in the 20th and 21st centuries.

The Super Soaker experiment consisted of three rocket launches from Poker Flat Research Range within about 40 minutes.

The first two rockets dispersed trimethyl aluminum, which, when it reacts with oxygen, produces the harmless products of aluminum oxide, carbon dioxide and water vapor, as well as a bluish white glow. By tracking this glow, researchers can determine the winds over a wide range of altitudes, letting them see the weather conditions into which the water was released.

The third rocket, launched 90 seconds after the second rocket, carried the water canister. The canister was detonated at an altitude of 53 miles to create a small polar mesospheric cloud that was detectable only by the lidar.

Researchers are eager to conduct a second Super Soaker, one that will eject much more water.

"What we saw was very, very fine, and we'd like to get more water up there to get a thicker cloud and see if we can directly measure the cooling effect rather than inferring it from the fact that the cloud formed," Collins said, referring to data acquired from the ground-based lidar.

A new study shows that a widespread decline in abundance of emergent insects - whose immature stages develop in lakes and streams while the adults live on land - can help to explain the alarming decline in abundance and diversity of aerial insectivorous birds (i.e. preying on flying insects) across the USA. In turn, the decline in emergent insects appears to be driven by human disturbance and pollution of water bodies, especially in streams. This study, published in Frontiers in Ecology and Evolution, is one of the first to find evidence for a causal link between the decline of insectivorous birds, the decline of emergent aquatic insects, and poor water quality.

Human activities, such as urbanization and agriculture, have adverse effects on aquatic ecosystems. In the US, 46% of streams are in poor condition, while 57% of lakes suffer from strong human disturbance. The immature stages of aquatic insects, especially stoneflies, mayflies and caddisflies, are known to be highly sensitive to pollution, which is why they have often been used as biomonitors for water quality. But the authors of the present study predicted a priori that emergent insects - whose adult flying stages are important sources of food for birds, spiders, bats and reptiles - should likewise be powerful biomonitors for the health of terrestrial ecosystems. This prediction is borne out by the new results.

"The massive decline in bird fauna across the USA requires that we adopt new paradigms for conservation. Currently, most management and conservation agencies and plans are separated into aquatic and terrestrial divisions. However, aquatic and terrestrial ecosystems are inextricably linked through a suite of ecological connections," says author Dr Mažeika Sullivan, associate professor in the School of Environment and Natural Resources and Director of the Schiermeier Olentangy River Wetland Research Park at Ohio State University.

Sullivan and colleagues analyzed data from multiple open-access surveys monitoring water quality, aquatic invertebrates and 21 species of aerial insectivorous birds from the contiguous United States. "The task of putting together these big data sets, collected by different US agencies with different goals and objectives, revealed several new questions and challenges which will require interdisciplinary thinking to resolve," says corresponding author Dr David Manning, assistant professor in the Department of Biology, University of Nebraska at Omaha.

First, the authors show that water quality is a good predictor for local relative abundance of emergent insects. Then they show for the first time that water quality and the associated abundance of emergent insects explains a moderate but significant proportion of the variation in local abundance of aerial insectivorous birds in the US, including both upland and riparian (i.e. foraging on river banks) species.

Not all bird species were equally negatively impacted by declines in the abundance of emergent insects, suggesting that factors such the birds' microhabitat and foraging strategy may also play a role. The western wood pewee (Contopus sordidulus, an upland bird species), the olive-sided flycatcher (C. cooperi, which facultatively lives in riparian zones), and the Acadian flycatcher (Empidonax virescens, which almost exclusively occurs near water) depended most strongly on the local abundance of overall emergent insects. The eastern phoebe (Sayornis phoebe), violet-green swallow (Tachycineta thalassina), tree swallow (Tachycineta bicolor), eastern wood-pewee (C. virens), barn swallow (Hirundo rustica), and chimney swift (Chaetura pelagica), were specifically sensitive to the relative abundance of stoneflies, mayflies and caddisflies.

The authors emphasize the need for interdisciplinary research to develop new conservation and biomonitoring strategies focused on the effects of water quality on endangered birds and other terrestrial wildlife.

"We need a better understanding of the common mechanisms that could drive declines in both aquatic insects and many bird species. We would like to explore some of these shared mechanisms in future research, but at a much larger scale than previously. Tackling these questions will require collaboration among freshwater ecologists, ornithologists, landscape ecologists, entomologists, data scientists, and others," says Manning.

Tohoku University researchers have produced cellulose nanofiber (CNF) synthesized silk naturally through a simple tweak to silkworms' diet. Mixing CNF with commercially available food and feeding the silkworms resulted in a stronger and more tensile silk.

The results of their research were published in the journal Materials and Design on February 1, 2021.

"The idea for our research came to us when we realized the flow-focusing method by which silkworms produce silk is optimal for the nanofibril alignment of CNF," said Tohoku University materials engineer Fumio Narita and co-author of the study.

Silk is usually associated with clothes. But its usage is incredibly diverse thanks to its strength and elastic properties. Its biocompatibility makes it even safe to use inside the human body.

Because of this, researchers have been investigating ways to further strengthen silk. Processes investigated thus far, however, require the use of toxic chemicals that are harmful to humans and the environment.

Cellulose nanofibers--plant derived fibers that have been refined to the micro-level-- show promise in synthesizing low-cost, lightweight, high strength, and sustainable nanocomposites such as silk.

However, previous CNF based synthesized materials have demonstrated few mechanical improvements even with the benefit of expensive equipment due to the lack of nanofibril alignment.

In contrast, silkworms produce silk in a flow-focused method. Silk is dispersed via their salivary glands, orientating the fibrils along the flow direction and thus enabling better nanofibril alignment.

In the present study, silkworm larvae were divided into three groups and reared on food containing differing amounts of CNF content. The research group performed strength tests on the drawn silk fibers which were found to be about 2.0 times stronger than the silk from non-CNF fed silkworms.

"Our findings demonstrate an environmentally friendly way to produce sustainable biomaterials by simply using the CNF as bait," said Narita.

Converting both nitrogen (N2) and carbon dioxide (CO2) into value-added urea molecules via C-N coupling reaction is a promising method to solve the problem of excessive CO2 emissions.

Compared with huge energy consumption industrial processes, the electrochemical urea synthesis provides an appealing route under mild conditions. However, it still faces challenges of low catalytic activity and selectivity.

A research team led by Prof. ZHANG Guangjin from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences fabricated Bi-BiVO4 Mott-Schottky heterostructure catalysts for efficient urea synthesis at ambient conditions.

This work was published in Angewandte Chemie International Edition on Feb. 25.

The spontaneous charge transfer at the heterointerfaces promotes the formation of space-charge region. "The space-charge region not only facilitates the targeted adsorption and activation of CO2 and N2 molecules on the generated electrophilic/nucleophilic regions, but also effectively suppresses CO poisoning and the formation of endothermic *NNH intermediate," said Prof. ZHANG.

The adsorbed *N2 can promote CO2 reduction to form CO, and then the generated CO will further react with *N2 to produce the desirable *NCON* intermediate via electrochemical C-N coupling reaction.

"The subsequent protonation process preferentially undergoes the alternating mechanism until the formation of urea," said Prof. ZHANG.

The researchers used linear sweep voltammetry (LSV) to preliminarily evaluate the potential performance of urea electrosynthesis with Bi-BiVO4 hybrids. The results showed that Bi-BiVO4 hybrids exhibited good performance in electrocatalytic nitrogen reduction reaction (NRR) and CO2 reduction reaction (CO2RR), which ensured the electrocatalytic production of urea process.

If light is strongly concentrated in time and space, resulting in extreme photon densities, it can enable interaction with all conceivable materials. By using these ultrashort laser foci, even transparent materials can be modified, even though they ordinarily would not interact. Short, focused laser pulses can overcome this transparency and allow energy to be deposited completely contact-free. The exact response of the material to the radiation can be very diverse, ranging from marginal refractive index changes to destructive microscale explosions that evacuate entire areas.

Using the laser pulses for optical machining allows for equally diverse material modification, such as separating or joining using the same laser system. Due to the extremely short exposure time and low degree of thermal diffusion, neighboring areas remain completely unaffected, enabling true micron-scale material processing.

In "Structured light for ultrafast laser micro- and nanoprocessing" by Daniel Flamm et al., various concepts are presented for manipulating the spatial distribution of laser light at the focus in such a way that particularly efficient and, thus, industrially suitable processing strategies can be applied. For example, customized nondiffracting beams, generated by holographic axicons, can be used to modify glass sheets up to millimeter scales using single-passes and feed rates of up to a meter per second. The application of this concept to curved substrates and the development of a laser-based glass tube cutting is a groundbreaking advance. This capability has long been needed by the medical industry for the fabrication of glass items such as syringes, vials and ampoules. The machined surfaces produce excellent edge quality and are free from micro debris, to meet the demands of the consumer and medical industry.

This paper also demonstrates the potential of a newly introduced 3D-beam-splitter concept. Here, 13 identical copies of the original focus are distributed across the three-dimensional working volume using a single focusing objective, serving to increase the effective volume of a weld seam. The material's response to the pulse is directly measured using transverse pump-probe microscopy confirming a successful energy deposition with 13 individual absorption zones. The conducted experiment represents a prime example of three-dimensional parallel processing based on structured light concepts and demonstrates increased throughput scaling by exploiting the performance of high-power, ultrashort pulsed laser systems.

The broad accessibility of liquid crystal displays and their application to beam shaping using holography has also led the materials processing community to adopt structured light concepts. However, these approaches have not yet been translated into industrial processing, mainly because such displays cannot handle high optical powers and energies as well as the high programming effort required to construct digital holograms.

This paper was able to report significant progress on this front. With the presented double illumination concept, the liquid crystal display modulates both amplitude and phase of the illuminating optical field. By applying digital amplitude masks, arbitrary intensity profiles can be generated, offering benefits for formation of high spatial frequency, fine metal masks. The adapted flat-top intensity profiles depicted in the manuscript are generated without using complex Fourier coding strategies, making the concept a promising candidate for future digital optical processing heads.

The latest developments in fluorescence microscopy make it possible to image individual molecules in cells or molecular complexes with a spatial resolution of up to 20 nanometres. However, under certain circumstances, an effect occurs that falsifies the results: the laser light used can cause very reactive oxygen molecules to form in the sample. These can then damage the fluorescent dyes used to such an extent that they no longer fluoresce. Among microscopy experts, this effect is known as photobleaching.

However, various fluorescent dyes can also be transformed by photobleaching so that they absorb light of shorter wavelengths. "A previously red fluorescent dye then glows green. Its fluorescence has been shifted towards the blue range on the wavelength scale. This is why this effect is called photoblueing," explains Professor Markus Sauer, an expert in super-resolution microscopy from the Biocentre of Julius-Maximilians-Universität Würzburg (JMU) in Bavaria, Germany.

First exact description of photoblueing

Sauer's team now presents the exact molecular mechanism of photoblueing for cyanine dyes like Cy5 for the first time in the journal Nature Methods. Dr. Martin Schnermann from the Center for Cancer Research in Frederick (USA) is also involved in the publication.

"Because we understood the mechanism so precisely, we were able to prevent photoblueing by simple additives such as vitamin C or to increase it by adding a kind of catalyst," says Markus Sauer.

Preventing photoblueing can be quite important. Although the effect can only affect a few percent of the dye used, it can nevertheless lead to errors or misinterpretations of the microscopy, for example in energy transfer experiments (FRET). This is because the converted dyes are detected with the same high sensitivity as the starting products.

Simple buffers prevent photoblueing

"Our results show which dyes are affected and how photoblueing can be prevented by simple buffer additions," Sauer summarises the contents of the Nature Methods paper. "But they equally show how photoblueing can possibly be used advantageously for fluorescence imaging and for tracking single, specifically converted dye molecules."

That's exactly what Sauer's team plans to tackle next: Photoblueing is to be further developed for, among other things, the targeted tracking of individual bacterial and viral particles in infection processes.

A study by researchers at William & Mary's Virginia Institute of Marine Science suggests that continued warming of Atlantic coastal waters may enhance the spread of invasive blue catfish within the Chesapeake Bay and other estuaries along the U.S. East Coast.

The research, by Drs. Vaskar Nepal and Mary Fabrizio of VIMS, appeared in a recent issue of PLOS ONE. It builds on an earlier study by the two authors showing that blue catfish can better tolerate salinity spikes than most freshwater fishes, and thus may be able to expand their range downstream into mainstem Chesapeake waters, and from there into new Bay tributaries and even Delaware Bay. "Blue cats" were introduced to tidal freshwater stretches of the James, York, and Rappahannock rivers during the 1970s and 1980s to enhance recreational fisheries. They feed on vegetation, mollusks, and fishes, often out-competing native species such as white catfish. Their continued spread thus concerns fisheries managers.

The pair conducted their latest study to investigate the combined, long-term effects of salinity and temperature on catfish health and behavior. Nepal, now a post-doctoral research associate at VIMS, says "By manipulating both factors, we were able to address an important knowledge gap and more closely simulate real-world conditions, where salinity and temperature can and do vary over a range of time scales." East Coast estuaries are warmer and typically saltier during summer; colder and fresher during winter and spring. Their heat and salt content can also vary on shorter time-scales during rainy spells, drought, heat waves, or cold snaps.

The researchers studied the combined effects of salinity and temperature by monitoring the health and behavior of 160 juvenile blue catfish divided among two duplicate sets of eight tanks, each set with four levels of salinity (1, 4, 7 or 10 practical salinity units) and two temperature levels (54° F or 72° F). The salinity treatments represent a range from largely fresh (1 psu) to moderately brackish (10 psu) waters, as found in many Bay tributaries. The temperatures are typical of Chesapeake Bay waters occupied by blue catfish during winter and spring. All tanks and fish were monitored inside the VIMS Seawater Research Laboratory for more than three months.

Nepal and Fabrizio assessed how the eight salinity and temperature combinations affected the fish's growth, body condition, body composition, and food consumption. Their results show that warmer water temperature has a positive effect on the biology of blue catfish under salinity conditions often encountered in estuarine waters.

"At salinities up to 7 psu, mean growth rate, body condition, and consumption rates were all higher at 72 degrees than at 54 degrees," says Nepal. "We measured the highest growth and body condition at 72 degrees and 4 psu." Warmer, fresher waters--as projected by climate models in the future Bay due to increased trapping of heat and enhanced precipitation--would thus appear to favor the spread and establishment of blue cats.

The average rate at which blue cats consumed their food did decline significantly at salinities greater than 9 psu. This was not unexpected, as that is the internal salinity of most freshwater fishes. When bathed in waters saltier than their own internal tissues, fish must expend considerable energy to prevent osmosis from driving bodily fluids into the surrounding water. That extra energy expenditure decreases the fish's overall health. In Nepal and Fabrizio's experiments, blue catfish held at 10 psu showed low consumption rates, slow growth, and low body condition.

Fabrizio, a professor and chair of the Fisheries Science Department at VIMS, says "Habitats with salinities higher than 9 psu likely will not support the full life-cycle of blue catfish, but the fish may use salinities up to 10 psu for foraging, dispersal, and even growth."

"Many brackish habitats along the U.S. East Coast may thus be vulnerable to invasion by blue catfish," says Nepal, "particularly given increasing temperatures due to climate warming."

"Given these findings," he adds, "state and regional management agencies should pay close attention to habitats at these salinities, especially in areas that provide nursery habitat for native species of conservation concern."

Sea-level rise promises one bright spot for those concerned with the spread of blue catfish. "Our rising seas are projected to bring saltier waters farther up our estuaries and tributaries," says Nepal. "This salinity intrusion may serve to limit dispersal between tributaries and form discrete subpopulations of blue catfish that are only connected during periods of high freshwater flow."

A Mason Engineering researcher has discovered that artificial microswimmers accumulate where their speed is minimized, an idea that could have implications for improving the efficacy of targeted cancer therapy.

Jeff Moran, an assistant professor of mechanical engineering in the Volgenau School of Engineering, and colleagues from the University of Washington in Seattle studied self-propelled half-platinum/half-gold rods that "swim" in water using hydrogen peroxide as a fuel. The more peroxide there is, the faster the swimming; without peroxide in pure water, the rods don't swim.

In this work, they set out to understand what happens when these artificial microswimmers are placed in a fluid reservoir containing a gradient of hydrogen peroxide--lots of peroxide on one side, not much on the other side.

They found that, predictably, the microswimmers swam faster in regions with high peroxide concentration, says Moran, whose research was published in the new issue of Scientific Reports.

As others had observed, the direction of swimming varied randomly in time as the swimmers explored their surroundings. In contrast, in the low-concentration regions, the rods slowed down and accumulated in these regions over the course of a few minutes.

The results suggest a simple strategy to make microswimmers passively accumulate in specific regions, an idea that might have useful, practical applications, he says.

Swimming at the microscopic scale is a ubiquitous phenomenon in biology, Moran says. "Lots of cells and microorganisms, such as bacteria, can autonomously swim toward higher or lower concentrations of chemicals that benefit or harm the cell, respectively."

This behavior is called chemotaxis, and it's both common and important, he says. "For example, your immune cells use chemotaxis to detect and swim toward sites of injury, so they can initiate tissue repair."

Moran and colleagues, like others in the field, have long been curious whether artificial microswimmers can mimic cells by performing chemotaxis, continuously swimming toward higher chemical concentrations. Some had claimed that the platinum/gold rods, in particular, could swim autonomously toward peroxide-rich regions.

"We were skeptical of these claims since the rods aren't alive, and therefore they don't have the sensing and response capabilities that are necessary for cells to execute this behavior," he says.

"Instead, we found the opposite: the rods built up in the lower concentration regions. This is the opposite of what one would expect from chemotaxis," Moran says.

The researchers conducted computer simulations that predicted this and validated them with experiments, he says.

"We propose a simple explanation for this behavior: Wherever they are, the rods move in randomly varying directions, exploring their surroundings. When they get to a low-fuel region, they can't explore as vigorously. In a sense, they get trapped in their comfort zones," Moran says.

"Conversely, in the high-peroxide regions, they move at higher speeds and, because their direction is constantly changing, escape from these regions more often. Over time, the net result is that rods accumulate in low-concentration regions," he says. "They don't have any intelligence. They end up where their mobility is the lowest."

Moran says this research is promising from a technical standpoint because it suggests a new strategy to make chemicals accumulate in a highly acidic area.

"Due to their abnormal metabolic processes, cancer cells cause their immediate surroundings to become acidic. These are the cells that need the most drugs because the acidic environment is known to promote metastasis and confer resistance to drugs. Thus, the cells in these regions are a major target of many cancer therapies."

Moran and colleagues are now designing microswimmers that move slowly in acidic regions and fast in neutral or basic regions. Through the mechanism they discovered here, they hypothesize that acid-dependent swimmers will accumulate and release their cargo preferentially where their speeds are minimized, namely the most acidic and hypoxic regions of the tumor, where the most problematic cells reside.

There is much more research to be conducted, but "these rods may have the ability to deliver chemotherapy drugs to the cancer cells that need them the most," Moran says.

"To be clear, our study doesn't prove that chemotaxis is impossible in artificial microswimmers, period; just that these particular microswimmers don't undergo chemotaxis.

"Instead, we've identified an elegantly simple method of causing unguided microswimmers to accumulate and deliver drugs to the most problematic cancer cells, which could have implications for the treatment of many cancers, as well as other diseases like fibrosis. We're excited to see where this goes."

Heart problems cause disturbed gene activity in the brain's memory center, from which cognitive deficits arise. Researchers at the German Center for Neurodegenerative Diseases (DZNE), the University Medical Center Göttingen (UMG) and the German Center for Cardiovascular Research (DZHK) come to this conclusion based on laboratory studies. They consider that they have found a possible cause for the increased risk of dementia in people with heart problems. In mice, a specific drug which is known to affect gene activity alleviated the mental deficits. The involved experts see these results as potential approaches for therapies. The study data are published in the scientific journal "EMBO Molecular Medicine".

In Germany, about four million people are affected by what is called "heart failure": Their heart muscle is too weak to pump enough blood through the body and is therefore abnormally enlarged. Physical fitness and quality of life suffer as a result. Moreover, affected individuals have an increased risk of developing dementia. "People with cardiological problems and heart failure in particular may experience noticeable cognitive deficits and increased risk of developing Alzheimer's disease. Possible reasons include impaired blood supply to the brain and dysfunction of the hippocampus, which is the memory's control center," explained André Fischer, research group leader at the DZNE's Göttingen site and professor at the Department of Psychiatry and Psychotherapy at UMG. "Yet, there is a lack of therapies to effectively treat cognitive deficits in people with heart problems. This is because it is completely unclear which deficiencies are triggered in neurons. There was no data on this so far."

Stressed Cells

Now, a team led by Prof. André Fischer and Prof. Karl Toischer (Clinic of Cardiology and Pneumology at UMG and DZHK's Göttingen site) is presenting findings on this subject for the first time. The researchers observed in mice that impaired gene activity developed in the hippocampus as a result of heart problems. "In memory tests, mice with heart failure performed significantly worse than their healthy mates," Fischer explained. "We then examined the neurons of the hippocampus. In the mice with heart failure, we found increased cellular stress pathways and altered gene activity in neurons."

Tight Windings

The genome of a mouse - and also of humans - comprises around 20,000 genes. In any given cell, however, only a part of them is active, switched on, so to speak. This is not a mere on or off state: the activity can be strong or less strong. This depends, among other things, on how tightly the DNA (the thread-like molecule that carries the genome) is wound and how accessible the genes on it are. In both mice and humans, the DNA is more than a meter long. But in a cell, the molecule is so tightly packed that it fits into the nucleus. "Genes can only be active if they are accessible to the cell's machinery. To this end, the DNA needs to be wound a little more loosely at the relevant sites. This is similar to a ball of yarn with loops sticking out of it," said Fischer. In the current study, the DNA was found to be more tightly wound in neurons of mice with heart problems than in healthy mates. Various genes important for hippocampal function were therefore less active than in healthy mice.

A Drug Improved Memory

The scientists identified chemical changes in the histones as the cause of the tight winding. Histones are special proteins: The DNA wraps around them, much like yarn around a spool of thread. Fischer's research group has been studying histones and other players that influence gene activity for quite some time - in technical jargon they are called "epigenetic mechanisms". In this context, the researchers are also investigating drugs. In previous studies, they were able to show that the cancer drug "vorinostat" can alleviate genetically driven as well as age-related memory problems in mice. Currently, vorinostat is being investigated for the therapy of people with Alzheimer's in a clinical trial of the DZNE. In the current study, the scientists treated mice with heart failure with this drug. They found that the heart's pumping capacity did not change significantly, but memory performance improved.

Interdisciplinary Cooperation

"Vorinostat has been shown to act on histones and thus on gene activity. Our study thereby provides initial clues about the molecular processes that contribute to cognitive dysfunction following heart problems, and it indicates potential approaches for therapy," Fischer commented on the results. "Fact is, however, that we do not yet understand why, as a result of heart failure, gene activity in the hippocampus is disturbed. What is the role of the deficient blood supply to the brain? Does the troubled heart release substances that affect the histones? We intend to investigate this in patients with heart problems. As with our current study, which involved experts from neuroscience and cardiac research, we aim to address these questions in an interdisciplinary way."

HOUSTON - (Feb. 26, 2021) - Tracking the origin of synthetic genetic code has never been simple, but it can be done through bioinformatic or, increasingly, deep learning computational approaches.

Though the latter gets the lion's share of attention, new research by computer scientist Todd Treangen of Rice University's Brown School of Engineering is focused on whether sequence alignment and pan-genome-based methods can outperform recent deep learning approaches in this area.

"This is, in a sense, against the grain given that deep learning approaches have recently outperformed traditional approaches, such as BLAST," he said. "My goal with this study is to start a conversation about how to combine the expertise of both domains to achieve further improvements for this important computational challenge."

Treangen, who specializes in developing computational solutions for biosecurity and microbial forensics applications, and his team at Rice have introduced PlasmidHawk, a bioinformatics approach that analyzes DNA sequences to help identify the source of engineered plasmids of interest.

"We show that a sequence alignment-based approach can outperform a convolutional neural network (CNN) deep learning method for the specific task of lab-of-origin prediction," he said.

The researchers led by Treangen and lead author Qi Wang, a Rice graduate student, reported their results in an open-access paper in Nature Communications.

The open-source software is available here: https://gitlab.com/treangenlab/plasmidhawk.

The program may be useful not only for tracking potentially harmful engineered sequences but also for protecting intellectual property.

"The goal is either to help protect intellectual property rights of the contributors of the sequences or help trace the origin of a synthetic sequence if something bad does happen," Treangen said.

Treangen noted a recent high-profile paper describing a recurrent neural network (RNN) deep learning technique to trace the originating lab of a sequence. That method achieved 70% accuracy in predicting the single lab of origin. "Despite this important advance over the previous deep learning approach, PlasmidHawk offers improved performance over both methods," he said.

The Rice program directly aligns unknown strings of code from genome data sets and matches them to pan-genomic regions that are common or unique to synthetic biology research labs

"To predict the lab-of-origin, PlasmidHawk scores each lab based on matching regions between an unclassified sequence and the plasmid pan-genome, and then assigns the unknown sequence to a lab with the minimum score," Wang said.

In the new study, using the same dataset as one of the deep learning experiments, the researchers reported the successful prediction of "unknown sequences' depositing labs" 76% of the time. They found that 85% of the time the correct lab was in the top 10 candidates.

Unlike the deep learning approaches, they said PlasmidHawk requires reduced pre-processing of data and does not need retraining when adding new sequences to an existing project. It also differs by offering a detailed explanation for its lab-of-origin predictions in contrast to the previous deep learning approaches.

"The goal is to fill your computational toolbox with as many tools as possible," said co-author Ryan Leo Elworth, a postdoctoral researcher at Rice. "Ultimately, I believe the best results will combine machine learning, more traditional computational techniques and a deep understanding of the specific biological problem you are tackling."

TORONTO, Feb. 26, 2021 - The maternal care of offspring is one of the behavioural drivers that has led some bee species to have an ever-expanding social life over the history of evolution, new research out of York University has found.

By virtue of being in a social group, the genome itself may respond by selecting more social rather than non-social genes. The behaviour and social environment come first, setting the stage for future molecular evolution.

In addition, the researchers have found that a similar genetic evolution happened independently in different species at different times, suggesting there is a unifying principle leading to the same social trait.

"There seems to be something about sociality specifically that is driving the genome to evolve in this way. It's a very interesting finding previously reported only in ants and honeybees," says lead researcher Associate Professor Sandra Rehan of the Faculty of Science.

Rehan and her team looked at 16 different bee species across three different independent origins of eusociality - the transition from solitary to social life where bees or other species live in a multigenerational group cooperatively caring for offspring in which there is a reproductive division of labour.

They also sequenced the genome of six of the carpenter bee species - one from North America, three from Australia, one from Japan and another from Kenya - to find out how sociability effects genome evolution. They found that caring for the species' young in a group has in many cases led to the selection of social rather than non-social gene regulation.

"When we see the rise of queens and workers in complex sociality, we tend to see a rise of more complex genomic signatures, rates of evolution in the genome, but also the complexity of the structure of the genomes," says Rehan. "We know so little about how sociality evolves."
Most bees are solitary, but some, like honeybees and carpenter bees, have transitioned to being social. Overall, though, sociality is relatively rare in the animal kingdom, and in bees.

"We are trying to understand how life evolved from simple to complex. We're mostly interested in how they got there. By studying these kinds of intermediatory groups and simple societies, we really can ask that question empirically," says Rehan.

"It gives us a window into the evolution of complexity and behaviour broadly. We can study it very practically in insects and bees because they show remarkable diversity in behaviour, but it gives us insights into all animals, including ourselves."

The research was published today in the Nature journal, Communications Biology.

COLUMBIA, Mo. -- Marilyn Rantz still remembers the day she got the call that her mother, whose health had been declining, had fallen and fractured her shoulder. After rushing to the hospital, her mother told her she didn't understand how she ended up on a helicopter pad after the traumatic incident. A nearby nurse told Rantz the noise from the MRI scanning tube had caused her frightened mother to mistakenly believe she had been airlifted to the hospital on a helicopter.

Determined to prevent avoidable hospitalizations, as well as the stress and panic that often comes along with the ambulance ride, Rantz, now a Curators' professor emerita at the University of Missouri's Sinclair School of Nursing, dedicated her career to improving the quality of care in nursing homes. In a recent study, Rantz and her team evaluated the effectiveness of the Missouri Quality Improvement Initiative, a $35 million program funded by the Centers for Medicare and Medicaid that implemented advanced practice registered nurses (APRNs) full time into 16 Missouri nursing homes. They recently evaluated the program over a six-year period and found the APRNs improved the quality of care for nursing home residents which resulted in reduced avoidable hospitalizations and emergency room visits, leading to better overall health and more than $31 million in savings.

"These highly qualified nurses have either a doctoral or master's degree in nursing, and their impact on both reducing costs and improving quality of care is significant," Rantz said. "Most of the care nursing home residents need can be provided right there in the nursing home. With the APRNs' advanced training, they have been able to help the nursing home staff recognize issues early and identify declines in health status quickly so that evidence-based interventions could be implemented to help avert problems such as hospital transfers or emergency room visits."

Rantz added that dehydration tends to be an underlying cause in many avoidable hospitalizations, and the quality improvement program puts protocols in place to ensure residents are hydrated as well as active and moving to improve mobility.

"We put care systems in place to allow residents to receive additional fluids several times a day," Rantz said. "Having the APRNs teach the nursing home staff about what types of things to be alert for helped identify small issues and early signs of illness before they became bigger issues that required an avoidable hospitalization."

Given the high rates of staff turnover nursing homes often face, the implementation of APRNs working full time in the nursing homes while being guided by a support team successfully sustained the improved quality of care in the majority of nursing homes over a six-year period.

"When residents did become ill, whether it was a urinary tract infection or pneumonia, we have previously seen these types of illnesses often lead to hospital transfers or emergency room visits," said Amy Vogelsmeier, an associate professor in the Sinclair School of Nursing and corresponding author on the study. "Now, with the APRNs coaching and mentoring the nursing home staff, they can provide the right IV fluids or give antibiotics so the residents are being appropriately cared for while still being able to remain in the long-term care living facility."

Since older adults tend to lose functional mobility with age, Rantz is committed to helping avoid traumatic and stressful hospital transfers like the one her mother experienced.

"If we can intervene and manage these residents in nursing homes where they are already familiar with the staff and the routine, that is the best place for them to be," Rantz said. "This is truly why I believe I was put on this Earth. This is my life's work, to help improve the care for older adults."

"Results of the Missouri Quality Initiative in sustaining changes in nursing home care: Six-year trends of reducing hospitalizations of nursing home residents" was recently published in The Journal of Nutrition, Health & Aging. Funding for the study was provided by the Centers for Medicare and Medicaid.

The National Cancer Institute's Genomic Data Commons (GDC), launched in 2016 by then-Vice President Joseph Biden and hosted at the University of Chicago, has become one of the largest and most widely used resources in cancer genomics, with more than 3.3 petabytes of data from more than 65 projects and over 84,000 anonymized patient cases, serving more than 50,000 unique users each month.

In new papers published Feb. 22 in Nature Communications and Nature Genetics, the UChicago-based research team shares new details about the GDC, which is funded by the National Cancer Institute (NCI), via subcontract with the Frederick National Laboratory for Cancer Research, currently operated by Leidos Biomedical Research, Inc. One of the papers describes the design and operation of the GDC. The other describes the pipelines used by the GDC for the harmonization of data submitted to the GDC and the generation of datasets used by the GDC research community.

The goal of the GDC is to provide the cancer research community with a data repository of uniformly processed genomic and associated clinical data that enables data sharing and collaborative analysis in the support of precision medicine.

Data production for what would become the GDC began in June 2015 using a private cloud. After just a year, the GDC had analyzed more than 50,000 raw sequencing data inputs. The GDC includes genomic, transcriptomic, epigenomic, proteomic, clinical, and imaging data. The processing pipelines described in the Nature paper have produced more than 1,660 TB of data on more than two dozen types of primary cancers. These data are stored within the GDC Data Portal, where they are available for viewing and downloading.

Along with the data portal, the GDC also offers additional user resources, including the GDC Data Analysis, Visualization, and Exploration (DAVE) Tools for interactive exploration of data by genomic variant or specific alteration; the GDC Data Submission Portal for submitting data; the GDC Data Transfer Tool (DTT) for downloading large genomic datasets; and the GDC data harmonization system, which allows users to run data submitted to the GDC through the harmonizing processing pipelines.

"These data have a critical role to play," said Robert Grossman, PhD, principal investigator for the GDC and director of the Center for Translational Data Science at UChicago. "As data accumulates, new signals will become easier to identify as important targets for understanding cancer biology. In addition, the data-sharing infrastructure can serve to inform research studies, providing new insight into genetic variation between individuals and how it may affect cancer patient outcomes."

Scientists at UCL and the IIT -Istituto Italiano di Tecnologia (Italian Institute of Technology) have created a temporary tattoo with light-emitting technology used in TV and smartphone screens, paving the way for a new type of "smart tattoo" with a range of potential uses.

The technology, which uses organic light-emitting diodes (OLEDs), is applied in the same way as water transfer tattoos. That is, the OLEDs are fabricated on to temporary tattoo paper and transferred to a new surface by being pressed on to it and dabbed with water.

The researchers, who described the process in a new paper in the journal Advanced Electronic Materials, say it could be combined with other tattoo electronics to, for instance emit light when an athlete is dehydrated, or when we need to get out of the sun to avoid sunburn. OLEDs could be tattooed on packaging or fruit to signal when a product has passed its expiry date or will soon become inedible, or used for fashion in the form of glowing tattoos.

Professor Franco Cacialli (UCL Physics & Astronomy), senior author of the paper, said: "The tattooable OLEDs that we have demonstrated for the first time can be made at scale and very cheaply. They can be combined with other forms of tattoo electronics for a very wide range of possible uses. These could be for fashion - for instance, providing glowing tattoos and light-emitting fingernails. In sports, they could be combined with a sweat sensor to signal dehydration.

"In healthcare they could emit light when there is a change in a patient's condition - or, if the tattoo was turned the other way into the skin, they could potentially be combined with light-sensitive therapies to target cancer cells, for instance.

"Our proof-of-concept study is the first step. Future challenges will include encapsulating the OLEDs as much as possible to stop them from degrading quickly through contact with air, as well as integrating the device with a battery or supercapacitor."

The OLED device the researchers developed is 2.3 micrometres thick in total (less than one 400th of a millimetre) - about a third of the length of a single red blood cell. It consists of an electroluminescent polymer (a polymer that emits light when an electric field is applied) in between electrodes. An insulating layer is placed in between the electrodes and the commercial tattoo paper.

The light-emitting polymer is 76 nanometres thick (a nanometre is a millionth of a millimetre) and was created using a technique called spin coating, where the polymer is applied to a substrate which is spun at high speed, producing an extremely thin and even layer.

Once they had built the technology, the team applied the tattooable OLEDs, which emitted green light, on to a pane of glass, a plastic bottle, an orange, and paper packaging.

Senior author Professor Virgilio Mattoli, researcher at Italian Institute of Technology said: "Tattoo electronics is a fast-growing field of research. At the Italian Institute of Technology we have previously pioneered electrodes that we have tattooed onto people's skin that can be used to perform diagnostic tests such as electrocardiograms. The advantage of this technology is that it is low-cost, easy to apply and use, and washes off easily with soap and water."

OLEDs were first used in a flatscreen TV 20 years ago. Among the advantages of the technology are that they can be used on flexible, bendy surfaces, and that they can be made from liquid solvents. This means they are printable, providing a cheap way to create bespoke new OLED designs.