Tech

A new momentum microscopy experimental station for photoelectron spectroscopy resolved in 3D momentum space with a microscopic field of view has been built at BL6U of UVSOR*, Institute for Molecular Science. The momentum microscope opens the door to direct observation of the Fermi surface and band structure of µm-sized targets such as surface atomic sites, thin films and interfaces, molecular adsorbates, and polycrystals, which was difficult with conventional electron energy analyzers.

Understanding based on the atomic level characterization methods is becoming increasingly important in elucidating new quantum phenomena and developing functional materials and devices. In photoelectron spectroscopy (PES), the photoelectrons emitted from the sample surface irradiated with X-rays are measured to clarify the composition and electronic structure of the sample. So far, high-resolution electron analyzers have been developed to measure the valence band dispersion of crystalline samples, but they average information over a wide field of view. However, the most interesting materials and useful devices are often micrometer-scale polycrystalline or highly integrated structures. Therefore, a high-specification electron energy and momentum analysis apparatus that also has microscope functions was desired. The momentum microscope, a combination of projection-type electron analyzer and photoelectron microscope, simultaneously realizes a microscope function for magnifying and observing minute parts of complicated-structured samples with element selectivity and a spectroscopy function for visualizing electron behavior (momentum) that determines the electronic properties of a sample. Now we have introduced the latest momentum microscope at the undulator-based soft X-ray beamline of UVSOR providing the optimal energy light for valence bands and core levels of various elements. A spatial resolution of 50 nm for microscopy measurement were achieved. PES measurement with a momentum resolution of 0.01 Å-1 and an energy resolution of 20 meV were successfully demonstrated. The smallest field of view for PES is 2 µm in diameter. In addition to the features of momentum microscope, the sample temperature can be freely changed from 9 K (-264 °C) to 400 K (127 °C), which enables in-situ observation of phase transition in the materials. One can investigate how the composition, structure, and electronic state of materials are related to electronic properties and functions.

The momentum-resolved micro-photoelectron spectroscopy realized by this device is an important method for developing nanomaterial science and quantum device engineering through electronic structure analysis. It enables electronic property and function analysis from a new point of view, such as direct observation of structure and electronic state changes where superconductivity and catalytic activity are occurring. In addition to contributing to basic science and applied research, we aim to make this new pioneering analyzer and analysis method a precursor to measurement technology innovation. This work was published online in Japanese Journal of Applied Physics on May 21.

* UVSOR Synchrotron Facility:

UVSOR is a synchrotron radiation facility at Institute for Molecular Science, Japan with the world's highest performance in the extreme ultraviolet energy range and is widely used by domestic and overseas researchers. The extreme ultraviolet energy range is suitable for observing behavior of electrons which are responsible for properties of molecules and solids. Synchrotron radiation emitted from an electron storage ring with a circumference of about 50 meter is introduced into more than a dozen experimental stations in which a wide variety of researches on bioscience, environmental and energy sciences as well as physical and chemical sciences are conducted. Although it is the second oldest synchrotron radiation facility in Japan since the first light was observed in 1983, it successfully keeps state-of-the-art performance with undergoing intensive upgrades twice.

Before water produced during hydraulic fracturing is disposed of in waterways or reused in agriculture and other industries, chemists at The University of Toledo are zeroing in on water quality and environmental concerns of fracking wastewater to determine if it is safe for reuse.

The research scientists of the new Dr. Nina McClelland Laboratory for Water Chemistry and Environmental Analysis at UToledo created a new method that simultaneously identified 201 chemical compounds in fracking wastewater, called produced water.

The research, which is published in the Journal of Separation Science and was carried out in collaboration with scientists at The University of Texas at Arlington, shows that many of the chemicals found in produced water are carcinogens, solvents and petroleum distillates that can directly contaminate drinking water sources.

"The issue with produced water is that this is a very new and overlooked source of pollution, and disposal and purification practices are not yet fully optimized to guarantee total removal of environmental pollutants," said Dr. Emanuela Gionfriddo, assistant professor of analytical chemistry in the UToledo Department of Chemistry and Biochemistry and the School of Green Chemistry and Engineering. "Our work aimed to provide a new, simple and cost-effective method for the comprehensive characterization of chemicals and fill the gap of knowledge currently existing about the chemical composition of this waste product of the oil and natural gas industry."

Scientists and natural gas companies are seeking creative ways to use produced water because current treatment processes to remove salts and radioactive substances - processes that include reverse osmosis and distillation - are expensive.

"Current methods for chemical characterization of produced water can give an estimate of the total amount of contamination but do not give information about what type of contamination is present," Gionfriddo said. "It could be that a molecule can be still very toxic even if present at very low concentration, or it has the potential to accumulate in the body over time, so the point is to know exactly what is in produced water, not only how much."

Gionfriddo's research outlines how the chemists developed and optimized a thin-film, solid-phase microextraction approach to characterize the organic compounds in the produced water.

The team identified many chemicals, including a pesticide called atrazine; 1,4-dioxane, an organic compound that is irritating to the eyes and respiratory tract; toluene, which at low exposure has health effects like confusion, weakness, and loss of vision and hearing; and polycyclic aromatic hydrocarbons, which have been linked to skin, lung, bladder, liver and stomach cancers.

"There are many chemicals that still need to be identified at this time," said Ronald Emmons, UToledo Ph.D. candidate. "More research also is needed to test the uptake of these chemicals in crops when produced water is recycled for agriculture. We need to study if and how these chemicals from the produced water can accumulate in the soil watered with produced water and if these chemicals can transfer from the soil to the crops."

The collaborative research between UToledo and UT Arlington will continue using the new method for screening the presence of toxic molecules in produced water samples from various sampling sites in Texas.

UToledo scientists also are developing new methods for the extraction of heavy metals and rare earth elements that will aid the full characterization of produced water samples.

Due to the difficult accessibility and the high risk of collapse or explosion, the imaging of active volcanoes has so far been a great challenge in volcanology. Researchers around Edgar Zorn from the German Research Centre for Geosciences GFZ in Potsdam are now presenting the results of a series of repeated survey flights with optical and thermal imaging cameras at the Santa Maria volcano in Guatemala. Drones were used to observe the lava dome, a viscous plug of lava. The researchers were able to show that the lava dome shows movements on two different time scales: slow expansion and growth of the dome and fast extrusion of viscous lava. The study was published in the journal "Scientific Reports".

"We have equipped a drone with different cameras", says Edgar Zorn from GFZ, the first author of the study. "We then flew the drone over the crater at various intervals, measuring the movements of lava flow and a lava dome using a specific type of stereo photography with a precision never seen before." By comparing the data from the drone, we were able to determine the flow velocity, movement patterns and surface temperature of the volcano. These parameters are important for predicting the danger of explosive volcanoes. The researchers also succeeded in deriving the flow properties of the lava from these data.

"We have shown that the use of drones can help to completely re-measure even the most dangerous and active volcanoes on Earth from a safe distance," continues Edgar Zorn. "A regular and systematic survey of dangerous volcanoes with drones seems to be almost within one's grasp", says Thomas Walter, volcanologist at GFZ, who was also involved in the study.

The two cameras of the drone used on the Caliente volcanic cone of the Santa Maria volcano were able to take high-resolution photos on the one hand and thermal imaging on the other. Using a special computer algorithm, the researchers were able to create complete and detailed 3D models from these images. They obtained a 3D topography and temperature model of the volcano with a resolution of only a few centimetres.

Drone missions considerably reduce the risk for volcanologists, as the cameras can be flown directly to the dangerous spots without the scientists having to go near them themselves. Instead, the greatest challenge lies in the post-processing and calculation of the models. "The 3D models of the various flights must be positioned exactly so that they can be compared. This requires painstaking detail work, but the effort is worth it because even minimal movements become immediately visible," says Edgar Zorn. "In the study, we presented some new possibilities for the representation and measurement of certain ground movements, which could be very useful in future projects".

MADISON -- When most people think of ceramics, they might envision their favorite mug or a flowerpot. But modern technology is full of advanced ceramics, from silicon solar panels to ceramic superconductors and biomedical implants.

Many of those advanced polycrystalline ceramics are combinations of crystalline grains which, at the microscopic level, resemble a stone fence held together with limestone mortar. Like that fence, the strength of the ceramic is determined by the strength of the mortar--which in ceramics is the grain boundary, or the areas where the different grains meet.

Previously, most researchers believed the chemistry of these grain boundaries in ceramics was very stable. But a new study by materials science engineers at the University of Wisconsin-Madison shows that's not the case. In fact, in the important ceramic material silicon carbide, carbon atoms collect at those grain boundaries when the material is exposed to radiation. The finding could help engineers better understand the properties of ceramics and could aid in fine-tuning a new generation of ceramic materials.

The details of the study appear today in the journal Nature Materials.

Since the 1970s, researchers have been aware of similar radiation-induced segregation in metal alloys. Because metal atoms share electrons freely, they are able to mix and unmix easily. When they are bombarded by ion radiation, some of the atoms in the metals will pop out of place and move toward the grain boundaries, and if different types of atoms move at different rates, the chemistry of the alloy can be altered.

Atoms in ceramics are very selective about which neighbors they bond with and the bonds are much stronger than in metals. That's why researchers believed these atoms weren't subject to the same type of segregation. But when Izabela Szlufarska, a professor of materials science and engineering at UW-Madison, began looking closely at the grain boundaries of silicon carbide, that's not what she found.

"In silicon carbide, the silicon and carbon really want to be paired together; they want to be 50 percent carbon and 50 percent silicon," she says.

However, when her team ran simulations and also imaged the grain boundaries, the carbon concentration was only 45 percent at the boundaries. "The chemistry was just really off," she says. "That was the first surprise, since this material really wants to have ordered atoms."

This suggested that silicon carbide might also be susceptible to radiation-induced segregation. So Szlufarska and her team bombarded the substance with ion radiation, finding that between 300 degrees Celsius and 600 degrees Celsius, the grain boundaries experienced carbon enrichment.

At those energy levels, the radiation causes some carbon atoms to pop out of place, creating a pair of defects in the silicon carbide including an empty spot called a vacancy and a loose carbon atom called an interstitial. Those unattached interstitial atoms migrate to the grain boundaries where they accumulate, affecting the material's chemistry.

Besides the fact that researchers simply didn't believe this type of segregation could take place in ceramics, Szlufarska says that, until recently, they also lacked the tools to even investigate the phenomenon. After painstaking fabrication and preparation of the silicon carbide bi-crystals, state-of-the-art scanning transmission electron microscopy conducted at UW-Madison and Oak Ridge National Laboratory allowed the team to resolve the chemical composition along the grain boundaries.

The team believes the phenomenon is likely to occur in other polycrystalline ceramics as well. The process is a double-edged sword: On the one hand, radiation-induced segregation means ceramics are subject to the same types of damage and deterioration at their grain boundaries as metal alloys, though at different temperatures. On the other hand, the segregation could be useful in materials engineering to produce specialized versions of ceramics like silicon carbide, which is used in nuclear energy, jet engines and other high-tech applications.

"Maybe the radiation can be used as a tool to fine tune grain boundary chemistry," says Xing Wang, study co-author and a professor at Pennsylvania State University who worked on the research while earning his doctorate at UW-Madison. "That could be useful to us in the future."

An international team of scientists have identified candidate resistance genes that could protect ash trees from the Emerald Ash Borer (EAB), a deadly pest that is expected to kill billions of trees worldwide.

In the new study, published today in Nature Ecology & Evolution, researchers from Queen Mary University of London and the Royal Botanic Gardens, Kew, sequenced the genomes of 22 species of ash tree (Fraxinus) from around the world and used this information to analyse how the different species are related to each other.

Meanwhile, collaborators from the United States Department of Agriculture Forest Service in Ohio tested resistance of over 20 ash tree species to EAB by hatching eggs attached to the bark of trees, and following the fate of the beetle larvae. Resistant ash trees generally killed the larvae when they burrowed into their stems, but susceptible ones did not.

The research team observed that several of the resistant species were more closely related to susceptible species than to other resistant species. This meant the UK-based genome scientists were able to find resistance genes, by looking for places within the DNA where the resistant species were similar, but showed differences from their susceptible relatives.

Using this novel approach, the scientists revealed 53 candidate resistance genes, several of which are involved in making chemicals that are likely to be harmful to insects.

The findings suggest that breeding or gene editing could be used to place these resistance genes into ash species currently affected by EAB.

EAB has killed hundreds of millions of ash trees in North America over the last 10 years. Whilst individual ash trees can be protected by using insecticides, the only long-term solution for saving American ash populations is to breed trees with resistance to EAB.

The beetle is also a threat to European ash populations. It was discovered near Moscow around 15 years ago and has now spread into Ukraine.

In the study, the US researchers found that European ash was more resistant to EAB than the North American species. However, European ash trees are already affected by an epidemic of the fungal disease, ash dieback, and experts are yet to understand how the two threats might interact.

The study also involved colleagues from the United States Department of Agriculture's Agricultural Research Service and the Teagasc Forestry Development Department, Dublin, Republic of Ireland.

Dr Laura Kelly, an academic visitor at Queen Mary, Research Leader in Plant Health at the Royal Botanic Gardens, Kew and first author of the study, said: "Ash trees are key components of temperate forest ecosystems and the damage caused by EAB also puts at risk the many benefits that these forests provide. Our findings suggest that it may be possible to increase resistance in susceptible species of ash via hybrid breeding with their resistant relatives or through gene editing. Knowledge of genes involved in resistance will also help efforts to identify trees that are able to survive the ongoing threat from EAB, and in turn, could facilitate restoration of ash woodlands in areas which have already been invaded."

Professor Richard Buggs, Professor of Evolutionary Genomics at Queen Mary and Senior Research Leader in Plant Health at the Royal Botanic Gardens, Kew, said: "The emerald ash borer has killed hundreds of millions of ash trees in North America since it was accidentally imported to Detroit from Asia in wooden packaging. The beetle is now spreading across Europe, where we don't yet know how it will interact with the invasive fungal pathogen causing the ash dieback epidemic. We need to be prepared to take decisive action to stop the spread of pests and pathogens that damage trees and the natural environment, as well as pathogens that attack humans."

Dr Jennifer Koch, Research Biologist with the United States Department of Agriculture Forest Service, said: "These candidate resistance genes, once validated, have the potential to greatly expedite the breeding process and the production of improved planting stock for restoration of forests and landscapes decimated by EAB."

Professor Melanie Welham, BBSRC's Executive Chair, said: "These significant research findings demonstrate the importance of international collaboration to further fundamental knowledge of pathogen biology. By having a better understanding of the implications of tree diseases globally we are able to ensure appropriate approaches to their management."

Even though the deeper layers of the ocean are warming at a slower pace than the surface, animals living in the deep ocean are more exposed to climate warming and will face increasing challenges to maintain their preferred thermal habitats in the future.

Reporting in the journal Nature Climate Change, an international team of scientists, led by the University of Queensland in Australia and involving Hokkaido University, analyzed contemporary and future global patterns of the velocity of climate change across the depths of the ocean. Their metric describes the temporal rate and direction of temperature changes, as a proxy for potential shifts of marine biota in response to climate warming.

Despite rapid surface warming, the team found that global mean climate velocities in the deepest layers of the ocean (>1,000 m) have been 2 to nearly 4-fold faster than at surface over the second half of the 20th century. The authors point to the greater thermal homogeneity of the deep ocean environment as responsible for these larger velocities. Moreover, while climate velocities are projected to slow down under scenarios contemplating strong mitigation of greenhouse gas emissions (RCP2.6), they will continue to accelerate in the deep ocean.

"Our results suggest that deep sea biodiversity is likely to be at greater risk because they are adapted to much more stable thermal environments," says Jorge Garci?a Molinos, a climate ecologist at Hokkaido University's Arctic Research Center, who contributed to the study. "The acceleration of climate velocity for the deep ocean is consistent through all tested greenhouse gas concentration scenarios. This provides strong motivation to consider the future impacts of ocean warming to deep ocean biodiversity, which remains worryingly understudied."

Climate velocities in the mesopelagic layer of the ocean (200-1000 m) are projected to be between 4 to 11 times higher than current velocities at the surface by the end of this century. Marine life in the mesopelagic layer includes great abundance of small fish that are food for larger animals, including tuna and squid. This could present additional challenges for commercial fisheries if predators and their prey further down the water column do not follow similar range shifts.

The authors also compared resulting spatial patterns of contemporary climate velocity with those of marine biodiversity for over 20,000 marine species to show potential areas of risk, where high biodiversity and velocity overlap. They found that, while risk areas for surface and intermediate layers dominate in tropical and subtropical latitudes, those of the deepest layers are widespread across all latitudes except for polar regions.

The scientists caution that while uncertainty of the results increases with depth, life in the deep ocean is also limited by many factors other than temperature, such as pressure, light or oxygen concentrations. "Without knowing if and how well deep ocean species can adapt to these changes, we recommend to follow a precautionary approach that limits the negative effects from other human activities such as deep-sea mining and fishing, as well as planning for climate-smart networks of large Marine Protected Areas for the deeper ocean," says Garci?a Molinos.

Lyme disease can have unusual presentations. Physicians and the public should be aware of its different manifestations, as people spend more time outside in the warmer weather and as the areas in Canada where the black legged tick is found expand. Three articles in CMAJ (Canadian Medical Association Journal), whichdescribe a fatal case in a 37-year-old man, atypical skin lesions and heart abnormalities in a 56-year-old woman and severe neurological symptoms in a 4-year-old boy, illustrate the diversity in clinical presentations of Lyme disease.

Lyme disease can affect the heart (known as Lyme carditis), which can result in serious heart rhythm abnormalities in a small group of people. Clinicians should be aware of the possibility of Lyme carditis in people presenting with atrioventricular heart block, especially in areas where Lyme disease is endemic. Patients may have had a rash. Early treatment with antibiotics is recommended to avoid complications, even before a diagnosis is confirmed.

A fatal case of Lyme disease in a previously healthy 37-year-old man illustrates the challenges of diagnosing Lyme disease in the absence of classic symptoms. http://www.cmaj.ca/lookup/doi/10.1503/cmaj.191194

The patient originally presented to his family doctor with flu-like symptoms, including fever, sore throat, nasal congestion and migratory joint pain. Several weeks earlier, he had been in contact with ticks but didn't recall removing one. His physician suspected a viral infection, and the patient's symptoms resolved.

Weeks later, he developed heart palpitations, shortness of breath and chest discomfort for which he was sent to the emergency department. Lyme disease was suspected as electrocardiography (ECG) showed complete heart block. He was admitted to hospital and started on treatment for Lyme carditis, but his condition worsened quickly. Clinicians were unable to reverse the course of illness and he died. Serology results confirmed Lyme disease, and an autopsy showed signs of Lyme carditis.

"The diagnosis of Lyme carditis is based on clinical suspicion and serology consistent with acute Lyme disease," writes Dr. Milena Semproni, Infectious Diseases fellow at the University of Manitoba and Winnipeg Regional Health Authority, Winnipeg, Manitoba, with coauthors. "Unfortunately, diagnosis can be delayed while serology is being processed, and clinical suspicion should guide empiric treatment. Given that the early diagnosis is clinical, cases may be overlooked by clinicians, especially as Lyme disease moves into new geographic areas."

In suspected cases of Lyme carditis, patients should have an urgent ECG performed and be started on antibiotics without waiting for serologic confirmation.

The authors note that serious heart rhythm abnormalities and sudden cardiac death can occur in a small group of patients, although it is uncommon. In the 10 other North American cases of sudden cardiac death attributed to Lyme carditis described in the literature, 8 patients were male, and the cases occurred between June and November, when ticks are active.

A reflection written by the man's sister, with a video testimonial, https://youtu.be/lz7e29CewE8, describes the family's initial concern that this was Lyme disease, the heartbreak caused by his death and their hope for increased awareness and understanding of the disease.

Read a related article about a patient with a large red rash (erythema migrans), aches and chills who, after a second visit for heart palpitations, was found to have Lyme carditis. The patient recovered with antibiotic treatment. http://www.cmaj.ca/lookup/doi/10.1503/cmaj.191660

"Given that most conduction abnormalities caused by Lyme carditis resolve with appropriate antibiotic therapy, recognition of atypical dermatologic presentations in the context of Lyme carditis prevents unnecessary permanent pacemaker implantation in these young and otherwise healthy individuals," writes Dr. Adrian Baranchuk, Department of Medicine, Queen's University, Kingston, with coauthors.

While the bull's eye rash is usually considered a feature of Lyme disease, in some cases, the rash doesn't follow the usual pattern.

A third article describes a 4-year-old boy who presented to hospital with fever, vomiting, malaise, ataxia and aphasia. The article describes the differential diagnosis and investigations, which eventually led to a diagnosis of Lyme disease (neuroborreliosis). The boy recovered fully with antibiotic treatment. http://www.cmaj.ca/lookup/doi/10.1503/cmaj.191279

A new species proposed to be classified as Critically Endangered of miniaturised stump-toed frog of the genus Stumpffia, found in Madagascar, is named Stumpffia froschaueri after "the man from the floodplain full of frogs", Christoph Froschauer. The namesake of the new frog is famous for being the first, and European wide renowned, printer from Zürich, famous for printing "Historia animalium" and the "Zürich Bible".

Christoph Froschauer's (ca. 1490 - April 1564) family name means "the man from the floodplain full of frogs", and the printer used to sign his books with a woodcut, showing frogs under a tree in a landscape. Amongst his publications are works by Zwingli, Bullinger, Gessner, Erasmus von Rotterdam and Luther, and as a gift for his art, the printer was given citizenship in Zürich in 1519. Now, scientists have also honoured Froschauer's great contributions by naming a new frog species after him.

The discovery, made by an international team of scientists from CIBIO (Research Centre in Biodiversity and Genetic Resources) of the University of Porto, Zoological Society of London, University of Lisbon, University of Brighton, University of Bristol, University of Antananarivo and Museo Regionale di Scienze Naturali, is published in the open-access peer-reviewed journal ZooKeys.

The new species is reliably known only from a few specimens collected in three forest patches of the Sahamalaza region, an area severely threatened by fire, drought and high levels of forest clearance.

"In Anketsakely and Ankarafa this species has been found only in areas with relatively undisturbed forest, and active individuals were found during the day within the leaf-litter on the forest floor, where discreet calling males were also detected", shares lead author Dr. Angelica Crottini from CIBIO.

Even though two out of the three forest patches where Stumpffia froschaueri occurs are now part of a UNESCO Biosphere Reserve, there is a lack in forest border patrols and the area remains under strong pressure from slash-and-burn activities and timber harvesting. Habitat loss and fragmentation are likely to represent a huge threat to the species' survival and cause population declines, unless remedial actions to enforce the protection of these habitats are taken. The scientists suggest to classify Stumpffia froschaueri as a Critically Endangered species according to criteria of the IUCN Red List.

"We here reiterate the need to continue with field survey activities, giving particular attention to small and marginal areas, where several microendemic candidate species are likely waiting to be discovered and formally described. This description confirms the Sahamalaza Peninsula as an important hotspot of amphibian diversity, with several threatened species relying almost entirely on the persistence of these residual forest fragments", concludes Dr. Crottini.

In complex surgery, is there a correlation between the volume of services provided per hospital and the quality of treatment results? This is the question addressed in eight commissions on minimum volumes that the Federal Joint Committee (G-BA) awarded to the Institute of Quality and Efficiency in Health Care (IQWiG). The IQWiG report is now available for the fifth intervention to be tested, kidney transplantations.

According to the findings, for kidney transplantations there is a correlation between the volume of services and the quality of treatment results: In hospitals with larger case volumes, the survival probabilities are higher up to one year after transplantation. No correlation between the volume of services and the quality of treatment results can be inferred for the outcome "transplant failure".

The most common organ transplantation in Germany

In chronic kidney failure, which is mostly caused by diabetes or high blood pressure, kidney transplantation is the only treatment option besides dialysis. The organ is donated either as a post-mortem donation or as a living donation from direct relatives or people very close to the patient. Five years after transplantation, 78 percent of post-mortem kidney donations and 87 percent of living kidney donations still function in the new body (figures for Europe). Kidney transplantation is the most common organ transplantation in Germany: In 2018, doctors in Germany transplanted 1671 kidneys after post-mortem organ donation and 638 kidneys after living donation. The waiting list for a donor kidney included more than 7500 patients in the same year. The average waiting time for a kidney transplant is currently more than 8 years.

Currently, a minimum of 25 procedures per hospital location and year is required for kidney transplantations (including living donations) in Germany. In contrast to the regulation on the annual minimum volume for liver transplantations, organ removals are not counted as part of the number of procedures required to achieve the minimum volumes.

Positive correlation between volume of services and survival probability

The question as to whether hospitals with larger case volumes achieve better treatment results for kidney transplantations than hospitals with smaller case volumes can be answered affirmatively by IQWiG for the survival probabilities of patients on the basis of a short-term observation period: For all-cause mortality up to 12 months after transplantation, two of the three studies assessed in this context show a lower probability of dying with a higher volume of services, although the informative value of the results is low. The IQWiG researchers cannot infer such a correlation for medium-term all-cause mortality after 36 months, for which a US study had collected data. After analysing the data from two relevant studies, the Institute also sees no correlation overall between the volume of services and the quality of treatment results for the outcome "transplant failure". No usable data were available for the outcomes "adverse effects of treatment", "health-related quality of life" and "length of hospital stay", so that no conclusions can be drawn here.

Since none of the included studies considered the individual volumes of services of the surgeons, it is also not possible to assess whether greater routine in kidney transplantations leads to better treatment results.

There are no studies on the effects of specific minimum case volumes introduced into the health care system for kidney transplantations. IQWiG can therefore draw no conclusions here either.

Process of report production

In February 2019, the G-BA commissioned IQWiG to prepare the report on the correlation between the volume of services and the quality of treatment results for kidney transplantations in an accelerated procedure as a so-called rapid report. Interim products were therefore not published or made available for a hearing. The work on the project started in August 2019. This rapid report was sent to the contracting agency, the G-BA, in April 2020.

An English extract of this rapid report will be available soon. If you would like to be informed when it is published, please contact info@iqwig.de

Based on previously released data and their own investigations, researchers at the St Petersburg University Laboratory of Macroecology and Biogeography of Invertebrates have assessed the diversity of freshwater molluscs in the Circumpolar region of the World. In total, they registered 104 species of these invertebrates living in waters within the Arctic Circle. Their hermaphroditism, their ability to freeze in ice and their 'friendship' with birds have all helped them to enter the Arctic and to survive under its harsh conditions.

The list of species compiled by the scientists reflects all of the information available on this question, including that which they themselves obtained during many expeditions into both Asian and American parts of the Circumpolar area. The last such list was published in Sweden in 1887, and now it is utterly outdated.

According to the authors, less than 2% of the world's freshwater molluscs have managed to find their way to the Arctic. Due to the peculiar life conditions in this region, the number of different species of snails and bivalves living there is small. Having analysed the biology and ecology of Arctic molluscs, the scientists speculated as to which biological traits helped these invertebrates make it to the Arctic Circle and survive there.

'Above all, it is their hermaphroditism, thanks to which any one of them can, when their numbers are limited, mate with any other member of the population, or even to fertilize oneself' said Maxim Vinarski, the head of the Laboratory of Macroecology and Biogeography of Invertebrates at St Petersburg University. 'Another useful trait is that they can travel by air, for example with birds being attached to their feathers or legs. Beyond that, the short life cycle of Arctic molluscs helps them to breed quickly and form sustainable populations in northern waters. It should also be pointed out that these invertebrates can overwinter being frozen into ice. It would seem that this combination of biological traits is the "entry ticket" to the Arctic for molluscs, allowing them to pass through an invisible filter created by the environment.'

A genetic and biogeographical analysis showed that no species of Arctic freahwater molluscs is endemic to this region; all species also occur elsewhere. It turns out that all freshwater molluscs that live in this circumpolar region came from lower latitudes. In 2017, Professor Vinarski and Ivan Nekhaev, a senior research associate in the Department of Applied Ecology at St Petersburg University, came up with similar findings for Greenland, and now their conclusions can be extended to cover the entire Arctic region. These scientists suggest that the absence of endemic molluscs north of the Arctic Circle is due to the geological youth of this region, which has comparatively recently shed its glacial covering.

The biologists also compared the species richness of freshwater molluscs in separate sub-regions of the Arctic: the European polar region, the far north of Siberia, Beringia and North America. It turns out that Siberia is the most diverse region, with 57 of the 104 species they described living there. The least diverse fauna is in North America, where only 39 species of freshwater molluscs occur. Such a disparity cannot be explained by an insufficient knowledge of North American molluscs, which have been under study for more than 200 years.

These scientists took a separate look at the Arctic and the subarctic geothermal waterbodies, which they believe could have served as a potential refuge for molluscs during the Pleistocene glacial epochs. Unlike most aquatic habitats of the northern polar region, whose thermal regime is determined to a great extent by seasonal changes of temperature, geothermal springs maintain high water temperature (more than 20 degrees Celsius, sometimes up to 40 degrees) year-round. Most freshwater snails and bivalves do not survive in such extreme conditions, but the University biologists established that no fewer than five species of the subclass Pulmonata (lung-breathing snails) are capable of overcoming the thermal shock after settling in geothermal springs and of forming viable populations there.

Although Arctic biota on the whole is extremely vulnerable to global changes and human impact, only three molluscs from those on the list have received international conservation status: Margaritifera margaritifera (a freshwater pearl mussel), Euglesa hinzi and Valvata mergella. Most Arctic species are abundant and quite widespread, but, according to the University biologists, this does not mean there is no need to protect them. In addition to the intense economic development of the Arctic, leading to the degradation of freshwater ecosystems, global climate changes have also had a negative impact.

'Because of warming in the Arctic, animal species that used to live in less harsh conditions have begun to filter into the region. And, with the global climate changes, we can already conclude that at least three species of snails and bivalves will be able to extend their habitats into the Extreme North. This might have an unpredictable effect on the indigenous ecosystems - it could, for instance, oust the native species of molluscs. It is also possible that the foci of parasitic diseases will move to the north, and many aboriginal freshwater molluscs will become the intermediate hosts of parasitic worms. Up until now, the effect of alien species on the Arctic freshwater communities has been minimal, but in the next few decades the situation could change,' Professor Vinarski cautioned.

Skoltech and MIPT scientists have predicted and then experimentally confirmed the existence of exotic hexagonal thin films of NaCl on a diamond surface. These films may be useful as gate dielectrics for field effect transistors in electric vehicles and telecommunication equipment.

As graphene, the famous two-dimensional carbon, was experimentally prepared and characterized in 2004 by future Nobel laureates Andre Geim and Konstantin Novoselov, scientists started looking into other 2D materials with interesting properties. Among these are silicene, stanene and borophene -- monolayers of silicon, tin, and boron, respectively -- as well as 2D layers of MoS2, CuO, and other compounds.

Skoltech PhD student Kseniya Tikhomirova, Dr. Alexander Kvashnin of Skoltech and Professor Artem R. Oganov of Skoltech and MIPT together with their colleagues built upon earlier studies of NaCl thin films to hypothesize the existence of an unusual nanometer-thick hexagonal NaCl film on the (110) surface of diamond.

"Initially we decided to perform only a computational study of the formation of new 2D structures on different substrates, driven by the hypothesis that if a substrate interacts strongly with the NaCl thin film, one can expect major changes in the structure of the thin film. Indeed, we obtained very interesting results and predicted the formation of a hexagonal NaCl film on the diamond substrate, and decided to perform experiments. Thanks to our colleagues who performed the experiments, we synthesized this hexagonal NaCl, which proves our theory," says Kseniya Tikhomirova, the first author of the paper.

Researchers first used USPEX, the evolutionary algorithm developed by Oganov and his students, to predict structures with the lowest energy based on just the chemical elements involved. After predicting the hexagonal NaCl film, they confirmed its existence by performing experimental synthesis and characterization by XRD (X-ray diffraction) and SAED (selected area electron diffraction) measurements. The average thickness of the NaCl film was about 6 nanometers -- a thicker film would revert from hexagonal to cubic structure, typical for the table salt we know.

Scientists believe that due to strong binding to the diamond substrate and a wide bandgap, hexagonal NaCl can work well as a gate dielectric in diamond FETs -- field-effect transistors that show potential for use in electric vehicles, radars, and telecommunication equipment. Now these FETs typically use hexagonal boron nitride, which has similar bandgap but much weaker binding to the substrate.

"Our results show that the field of 2D materials is still very young, and scientists have discovered only a small portion of possible materials with intriguing properties. We have a long-standing story starting in 2014 when we described the way cubic NaCl thin films can be split into hexagonal graphene-like layers. This shows that this simple and common compound, seemingly well-studied, hides many interesting phenomena, especially in nanoscale. This work is our first step towards the search for new materials like NaCl but having better stability (lower solubility, higher thermal stability, and so on) which then can be effectively used in many applications in electronics," notes Alexander Kvashnin, senior research scientist at Skoltech.

This work brings us closer to understanding how to control the appearance and, as a consequence, the properties of two-dimensional materials using a substrate. The research also opens the door to more 2D materials with potential applications in electronics and beyond.

This type of TNBC tumor does not express any of the receptors involved in most breast cancers (estrogen, progesterone and HER2), so the most common treatments, such as the hormone therapy, are not viable in these patients.

This new study is led by Mar Orzáez, principal researcher at the Laboratory of Peptide and Protein Chemistry at CIPF, and Ramón Martínez Máñez, member of the CIPF-UPV Joint Research Unit of Diseases Mechanisms and Nanomedicine, and research at the Interuniversity Research Institute for Molecular Recognition and Technological Development (IDM) of the UPV and at the Centro de Investigación Biomédica en Red (CIBER) in the subject area of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN). The study proves that a combined treatment of a senescence inducer and a senolytic nanoparticle selectively removes senescent cells, delays tumor growth and reduces metastasis in a model of aggressive breast cancer.

The application of senescence inducers has represented a successful strategy for treating breast cancer patients thus far, although the accumulation of senescent cells in the body can favor relapse of the tumor.

Senescence or cell aging occurs both in physiological and pathological situations. When a cell enters into senescence, it stops dividing and releases substances that cause inflammation.

When an uncontrolled accumulation of those senescent cells happens, the excess of inflammatory factors can eventually damage healthy cells, thus favoring aging and the appearance of disorders such as diabetes and neurodegenerative diseases, as well as fostering the developing of tumors and causing metastasis.

With this new approach, after inducing senescence, cells are removed through the treatment with a senolytic nanoparticle. This opens a new therapeutic opportunity to improve results with breast cancer patients and establishes a new combined treatment that can be significant for other senescence-inducing chemotherapy drugs.

The results, published in the Journal of Controlled Release (JCR), provide new therapeutic methodologies to be developed in subsequent stages and clinical trials. Moreover, they can address several types of tumor.

Orzáez and Máñez have explained that "the senescence induction in tumors represents an advance in cancer treatment, which may be even greater in combination with this type of senolytic treatments that remove senescent cells and help to reduce metastasis."

Using biologically inspired robotic swarms consisting of large groups of robots that have been programmed to operate cooperatively, much like individuals in an ant or bee colony, scientists from the University of Colorado demonstrate that the locally observed distribution of robots can be correlated to the location of environmental features, such as exits in office-like environments. The study's findings were published in IEEE/CAA Journal of Automatica Sinica.

According to Megan Emmons from Colorado State University, USA, this is an important study to establish the feasibility of using local observations of a swarm's distribution -- observing how individual robots in a swarm cluster together in certain areas -- to infer global environmental features such as building exits. "There is a wide variety of potential real-world applications once the proposed approach is developed further but the focus of our work is to assist rescue workers in navigating disaster sites safely and robustly," said Emmons.

Individual robots within a swarm are programmed with simplistic individual behaviors, lack the ability to communicate, relying solely on random motion to explore their surroundings. But as they interact with the environment and other robots in the swarm, more complex swarm behaviors start to emerge -- a phenomenon known as emergent swarm behaviors.

This "swarm" behavior can include traits such as group consensus, task allocation, and localization -- the process of determining where a robot is located with respect to its environment, enabling it to make decisions regarding future actions -- all of which have applications in environmental exploration. But for this study, the authors focused on the local distribution of the robots and show how these observations can be correlated to environmental features of the surroundings being explored. This in turn can help identify obstructions or openings in environments such as office buildings to help trapped office workers navigate their way out of a collapsed building, for example.

Currently, robotic exploration poses various challenges when used in disaster situations due to unreliable communication, limited sensing, and high failure rates of robots. The method used in this baseline feasibility study overcomes these limitations and confirms that a minimally equipped robotic swarm that lacks communication or sensors can still provide important information regarding environmental features in a simulated disaster scenario. One only needs to locally observe robot density in order to predict environmental features.

"Swarms offer an incredible increase in robustness," said Emmons. "From this work, we demonstrate that even in a worst-case scenario where you lose 9 out of 10 robots, have zero communication, and the robots are limited to purely random motion - an environment can still be classified with better-than-random accuracy."

"Future work will focus on extending this work more rigorously into domains where existing robotic solutions are known to fail," said Emmons.

Researchers in the US and Korea reported the first efficient flexible light-emitting diodes with a two-dimensional titanium carbide MXene as a flexible and transparent electrode. This MXene-based light-emitting diodes (MX-LED) with high efficiency and flexibility have been achieved via precise interface engineering from the synthesis of the material to the application (Advanced Materials,2020, 2000919).

Flexible displays have been developing with a high pace and the global flexible display market has been expanding quickly over the years. Development of flexible transparent conducting electrodes (TCEs) with outstanding flexibility and electrical conductivity is one of the key requirements for the next-generation displays because indium tin oxide (ITO), the conventional TCE, is brittle. Diverse materials such as graphene, conducting polymers and metal nanowires have been suggested but their insufficient electrical conductivity, low work function and complicated electrode fabrication limited their practical use.

MXenes, a new family of two-dimensional materials

MXenes, a new class of two-dimensional materials discovered at Drexel University in 2011, consist of few-atoms-thick layers of transition metal carbides or nitrides. They have shown impressive properties such as metal-like electrical conductivity and tunable surface and electronic properties, offering new possibilities to the various fields of technology. Since their discovery, their use has been explored in a number of areas, such as metal ion batteries, sensors, gas and electrochemical storage, energy devices, catalysts and medicine. MXenes have exhibited potential as flexible electrodes because of their superior flexibility. However, exploration of MXenes in flexible electrodes of optoelectronic devices just started recently because the conventional MXene films do not meet the requirements of work function and conductivity in LEDs and solar cells and can degrade when they are exposed to the acidic water-based hole injection layer (HIL).

MXene for flexible LED application

An international team of scientists from Seoul National University and Drexel University, led by Tae-Woo Lee and Yury Gogotsi focused on the surface and interface modulation of the solution-processed MXene films to make an ideal MXene/HIL system. They tuned the surface of the MXene film to have high work function (WF) by low-temperature vacuum annealing and the HIL is designed to be pH-neutral and be diluted with alcohol, preventing detrimental surface oxidation and degradation of the electrode film. The MXene/HIL system suggested by the team provides advantages to the device efficiency due to efficient injection of holes to the emitting layer by forming a nearly ideal Ohmic contact.

Using the MXene/HIL system, the team fabricated high-efficiency green organic LEDs (OLEDs) exceeding 100 cd/A, which agrees well with the theoretical maximum values and is quite comparable with that of the conventional ITO-based devices. Finally, flexible MXene-LEDs on a plastic substrate show outstanding bending stability while the ITO-LEDs could not stand the bending stress. It is the first report that demonstrates highly efficient OLEDs using a single layer of 2D titanium carbide MXene as a flexible electrode.

This progressive research is published in the prominent journal 'Advanced Materials' (IF: 25.809). The authors explain further: "The results of interface engineered MXene film and the MXene electrode-based flexible organic LEDs show the strong potential of the solution-processed MXene TCE for use in next-generation optoelectronic devices that can be manufactured using a low-cost solution-processing technology."

Most people at high risk of overdose in Vancouver's Downtown Eastside who use cannabis do so for pain relief and other therapeutic reasons--and they may be at lower risk of overdosing on opioids as a result, suggests new research published in the peer-reviewed journal PLOS ONE.

"We're seeing more and more in our research that people are using cannabis for therapeutic reasons," says Stephanie Lake, a doctoral candidate at UBC's School of Population and Public Health and the lead author of the study. "We're also seeing that, for some individuals in our study, this therapeutic use corresponds with either less use of illicit opioids or a reduced risk of overdose."

Researchers from the BC Centre on Substance Use (BCCSU) and the University of British Columbia (UBC) conducted more than 2,500 interviews with 897 people who use illicit drugs in Vancouver's downtown and Downtown Eastside who reported using cannabis between 2016 and 2018. They asked study participants to describe all the reasons why they used cannabis--for example, to relieve pain, improve sleep, address nausea, or intoxication--and built a statistical model to categorize those responses into discrete groups. Three of the four groups--encompassing almost three-quarters of study interviews--were characterized by therapeutic reasons for cannabis use.

Additionally, cannabis users in the group characterized by using cannabis for pain relief had lower odds of experiencing a recent non-fatal opioid overdose and injecting heroin every day in comparison to other groups. Previous research from the BCCSU found that many people at risk of overdose, particularly those living with pain, may be using cannabis to reduce their reliance on illicit opioids, a key driver of the opioid overdose public health emergency.

Another key finding of the study was that therapeutic cannabis users rely on the unregulated market to supply their cannabis use--and that access to legal cannabis for all people who use cannabis in the study remains a challenge. Participants in the current study reported that illegal dispensaries were the most important source of cannabis in approximately half of all study interviews; legal sources of cannabis (i.e., through the medical cannabis system or recreational cannabis stores) accounted for less than one per cent.

These findings are consistent with a study published earlier this month in the International Journal on Drug Policy, which found that illegal dispensaries are the primary source of cannabis in the community.

"The mounting evidence related to the motivations behind people's cannabis use strongly suggests that improving access to cannabis for therapeutic purposes could help reduce overdose risk associated with illicit opioid use," says Dr. M-J Milloy, a research scientist at BCCSU, the Canopy Growth professor of cannabis science at UBC and the senior author of the study. "Unfortunately, our results also tell us that medical cannabis users from the Downtown Eastside do not have equitable access to legal sources of cannabis, either through the medical cannabis system or the new recreational market. Authorities should pause their efforts to close unregulated sources of cannabis and eliminate the illicit market until barriers to legal cannabis are addressed, especially during the overdose crisis."

Milloy is supported by funding from the United States' National Institutes of Health, the Canadian Institutes of Health Research and the Michael Smith Foundation for Health Research, and National Green Biomed Ltd., a private firm seeking a licence to produce cannabis.

The Canopy Growth professorship in cannabis science at UBC was established through arms' length gifts from Canopy Growth, a licensed producer of cannabis, and the Government of British Columbia's Ministry of Mental Health and Addictions.