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Quasiperiodic structures, which are ordered but are not strictly periodic, are the source of extraordinary beauty in nature, art, and science. For physicists, quasiperiodic order is both aesthetically and intellectually appealing. Numerous physical processes that are well described in periodic structures fundamentally change their character when they happen in quasiperiodic systems. Add quantum mechanics, and striking new phenomena can emerge that remain not fully understood. Writing in Nature Physics, an international team led by Oded Zilberberg of the Institute of Theoretical Physics at ETH Zurich and by CNRS physics researchers Jacqueline Bloch of the Université Paris-Saclay and Alberto Amo of Lille University, now describes combined theoretical and experimental work in which they establish versatile tools for exploring the behaviour of quantum systems in a diverse range of one-dimensional quasiperiodic settings -- and demonstrate the strength of their approach to uncover new physical mechanisms.

Intricate beauty

The essence, and beauty, of quasiperiodic structures can be grasped by considering floor plates. A floor can be readily tiled without gaps using identical pieces of, for example, triangular, square or hexagonal shape, repeating a simple pattern. But a plane surface can also be fully covered in non-repeating patterns, and that by using just two types of rhomboid tiles, as the English physicist and mathematician Roger Penrose has famously shown (see the figure). In that case, even if local configurations appear in different places, the overall pattern cannot be superimposed with itself by translation and rotation. As such, these systems occupy some sort of middle ground between periodic and randomly disordered structures.

On that middle ground, there is intriguing physics to be explored. Take a perfectly ordered crystal. There, the periodicity permits wavelike propagation of electrons through the material, for instance in a metal. If the crystalline perfection is perturbed by introducing disorder, the behaviour changes. For low levels of disorder, the material still conducts, but less well. At some level of disorder though, the electrons stop propagating and become collectively localized, in a process known as Anderson localisation. For periodic lattices, this effect has first been described in 1958 (by 1977 Physics Nobel laureate Philip Anderson, who passed away on 29 March this year). But how such processes play out in quasiperiodic structures continues to be an area of active research.

Insightful interpolation

A wide range of unconventional physical phenomena have been described for quasiperiodic systems, but there exists no overarching framework for dealing with wave propagation in quasiperiodic structures. There are, however, various models that make it possible to study specific aspects of transport and localization. Two paradigmatic examples of such models are the Aubry-André and the Fibonacci models, each of which describes different physical phenomena, not least when it comes to localization properties.

In the Aubry-André model, there are two distinct parameter regions in which the particles can be in either 'extended' or localized states (in the same sense as electrons can either propagate through a material or be stuck in an insulating state). By contrast, in the Fibonacci model there is not one specific critical point separating the two regimes, but for any parameter the system is in such a critical state between localized and extended. Despite their sharply contrasting behaviours, the two models are connected to one another, and one can be continuously transformed into one another. This is something Zilberberg, then working at the Weizmann Institute of Science in Israel, had shown in breakthrough work with his colleague Yaacov Kraus in 2012. The question that remained was how the two so different localization behaviours are connected.

Piling up new insight

To answer that question, Zilberberg with his PhD student Antonio Štrkalj and his former postdoc Jose Lado (now at Aalto University) teamed up with CNRS experimentalists Jacqueline Bloch and Alberto Amo and their PhD student Valentin Goblot (now at the company STMicroelectronics). The French physicists had perfected a photonic platform -- so-called cavity-polariton lattices -- in which light can be guided through semiconductor nanostructures while experiencing interactions similar to those acting on electrons moving through a crystal. Importantly, they found ways to generate quasiperiodic modulations in their photonic wires that enabled them to implement experimentally, for the first time in any system, the Kraus-Zilberberg model. Optical spectroscopy experiments performed locally on these photonic quasi-crystals offer the exquisite possibility of directly imaging light localization in the systems.

By combining their theoretical and experimental tools, the researchers were able to trace how the Aubry-André model evolves to become fully critical in the limit of the Fibonacci model. Counter naïve expectation, the team showed that this does not happen in a smooth way, but through a cascade of localization-delocalization transitions. Starting, for example, from the region of the Aubry-André model where particles are localized, at each step of the cascade process energy bands merge in a phase transition, during which particles are passing through the material. At the other side of the cascaded transition, the localization roughly doubles, sending the states of Aubry-André model gradually towards full criticality as it morphs into the Fibonacci model.

The situation bears some resemblance to what happens to a pile of rice as grains are added one by one. For some time, newly added grains will just sit where they landed. But once the slope at the landing site exceeds a critical steepness, a local avalanche is induced, leading to a rearrangement of parts of the pile surface. Repeating the process eventually leads to a stationary pile where one additional grain can trigger an avalanche on any of the relevant size scales -- a 'critical' state. In the quasiperiodic systems, the situation is more complex because of the quantum nature of the particles involved, which means that these do not move like particles, but interfere like waves do. But in this setting as well, the evolution towards an overall critical state happens, as in the rice pile, through a cascade of discrete transitions.

With the theoretical description and experimental observation of this cascade to criticality, the teams have successfully connected quantum phenomena on two paradigmatic models of quasiperiodic chains, adding unique insight into the emergence of criticality. Moreover, they developed a flexible experimental platform for further explorations. The significance of these experiments goes firmly beyond light properties. The behaviour of electrons, atoms and other quantum entities is governed by the same physics, which could inspire new ways of quantum control in devices. Just as the appeal of quasiperiodic patterns transcends disciplines, the potential to inspire scientific and eventually technological advances seems similarly boundless.

Man's best friend may also be man's best bet for figuring out how environmental chemicals could impact our health. Researchers from North Carolina State University and Duke University's Nicholas School of the Environment used silicone dog tags as passive environmental samplers to collect information about everyday chemical exposures, and found that dogs could be an important sentinel species for the long term effects of environmental chemicals.

"Silicone monitoring devices are still relatively new, but they represent an inexpensive and effective way to measure exposure to the chemicals we encounter in daily life - from pesticides to flame retardants," says Catherine Wise, Ph.D. candidate at NC State and lead author of a paper describing the work. "And we know that many human diseases caused by environmental exposure are similar clinically and biologically to those found in dogs."

Wise and researchers from NC State and Duke recruited 30 dogs and their owners to wear silicone monitors for a five-day period in July 2018. Humans wore wristbands, while the dogs wore tags on their collars.

The researchers analyzed the wristbands and tags for exposures to chemicals within three classes of environmental toxicants that are often found in human blood and urine: pesticides, flame retardants, and phthalates, which are found in plastic food packaging and personal care products. They found high correlations between exposure levels for owners and their pets. Urinalysis also revealed the presence of organophosphate esters (found in some flame retardants) in both owners and dogs.

"What was remarkable about these results were the similar patterns of exposure between people and their pets," says Heather Stapleton, Ronie-Richelle Garcia-Johnson Distinguished Professor, director of the Duke Environmental Analysis Laboratory at the Nicholas School and co-author of the research. "It's quite clear that the home environment contributes strongly to our daily exposure to chemical contaminants."

However, while dogs and humans may share similar exposures, the health effects do not follow similar timelines - a fact that could aid researchers in teasing out relationships between chemical exposure and human health. "Dogs are special when it comes to linking exposures and disease outcomes because effects that may take decades to show up in humans can occur in one to two years in a dog," Wise says.

"Humans spend incredible amounts of time with their dogs - that's especially true right now," says Matthew Breen, Oscar J. Fletcher Distinguished Professor of Comparative Oncology Genetics at NC State and corresponding author of the paper. "If we develop ways to correlate dog disease with their exposures over time, it may give human-health professionals the opportunity to mitigate these exposures for both species. Dogs are a powerful biological sentinel species for human disease."

PULLMAN, Wash. - Washington State University (WSU) and Pacific Northwest National Laboratory (PNNL) researchers have created a sodium-ion battery that holds as much energy and works as well as some commercial lithium-ion battery chemistries, making for a potentially viable battery technology out of abundant and cheap materials.

The team reports one of the best results to date for a sodium-ion battery. It is able to deliver a capacity similar to some lithium-ion batteries and to recharge successfully, keeping more than 80 percent of its charge after 1,000 cycles. The research, led by Yuehe Lin, professor in WSU's School of Mechanical and Materials Engineering, and Xiaolin Li, a senior research scientist at PNNL is published in the journal, ACS Energy Letters.

"This is a major development for sodium-ion batteries," said Dr. Imre Gyuk, director of Energy Storage for the Department of Energy's Office of Electricity who supported this work at PNNL. "There is great interest around the potential for replacing Li-ion batteries with Na-ion in many applications."

Lithium-ion batteries are ubiquitous, used in numerous applications such as cell phones, laptops, and electric vehicles. But they are made from materials, such as cobalt and lithium, that are rare, expensive, and found mostly outside the US. As demand for electric vehicles and electricity storage rises, these materials will become harder to get and possibly more expensive. Lithium-based batteries would also be problematic in meeting the tremendous growing demand for power grid energy storage.

On the other hand, sodium-ion batteries, made from cheap, abundant, and sustainable sodium from the earth's oceans or crust, could make a good candidate for large-scale energy storage. Unfortunately, they don't hold as much energy as lithium batteries.

They also have trouble being recharged as would be required for effective energy storage. A key problem for some of the most promising cathode materials is that a layer of inactive sodium crystals builds up at the surface of the cathode, stopping the flow of sodium ions and, consequently, killing the battery.

"The key challenge is for the battery to have both high energy density and a good cycle life," said Junhua Song, lead author on the paper and a WSU PhD graduate who is now at Lawrence Berkeley National Laboratory.

As part of the work, the research team created a layered metal oxide cathode and a liquid electrolyte that included extra sodium ions, creating a saltier soup that had a better interaction with their cathode. Their cathode design and electrolyte system allowed for continued movement of sodium ions, preventing inactive surface crystal build-up and allowing for unimpeded electricity generation.

"Our research revealed the essential correlation between cathode structure evolution and surface interaction with the electrolyte," Lin said. "These are the best results ever reported for a sodium-ion battery with a layered cathode, showing that this is a viable technology that can be comparable to lithium-ion batteries."

The researchers are now working to better understand the important interaction between their electrolyte and the cathode, so they can work with different materials for improved battery design. They also want to design a battery that doesn't use cobalt, another relatively expensive and rare metal.

"This work paves the way toward practical sodium-ion batteries, and the fundamental insights we gained about the cathode-electrolyte interaction shed light on how we might develop future cobalt-free or low cobalt cathode materials in sodium-ion batteries as well as in other types of battery chemistries," Song said. "If we can find viable alternatives to both lithium and cobalt, the sodium-ion battery could truly be competitive with lithium-ion batteries.

"And, that would be a game changer," he added.

The authors recommend a needs-based system focusing on patient well-being and quality assurance, rather than a primarily profit-oriented approach. It should appreciate all employees and integrate innovations as well as digital solutions. The aim is an adaptive healthcare system where the public health service and the ambulatory and stationary sectors work together well, and research results are promptly integrated into clinical practice.

In the past weeks, the coronavirus pandemic has posed extraordinary challenges to the German healthcare system. According to the ad-hoc-statement, the confrontation with a new viral disease has shown the great importance of a publicly funded healthcare system and of an interconnected and research-based healthcare. Due to precautionary measures against infection with the largely unknown SARS-CoV-2 virus as well as the rearrangement of the system to be able to handle a potentially large number of severely ill COVID-19 patients, ambulatory and stationary care for patients with other illnesses has, however, faded into the background. Even important preventive measures and research activities had to be interrupted. Now, needs-based preventive, diagnostic and therapeutic measures for all patients need to be resumed promptly and, whenever possible, to their full extent.

The authors consider the following short- and medium-term framework conditions necessary to ensure healthcare for all patients in times of an ongoing pandemic threat:

provision of sufficient stationary, ambulatory, and post-stationary capacities and securing personnel, rooms and technical reserves for the treatment of COVID-19 patients when required

establishment of a regional and in-hospital early warning system for SARS-CoV-2 infections

implementation of science-based targeted testing strategies

strengthening public confidence in a safe and patient-oriented medical treatment

high-quality care and health services for all patients by promptly integrating new research developments

It is the responsibility of the state to ensure healthcare in times of crisis and a quality-assured and science-based medical treatment for the population. The working group of the German National Academy of Sciences Leopoldina recommends taking the following general aspects into account for the long-term development of the healthcare system:

ensuring high-quality, science-based and ethically responsible care for all patients

determining defined and differentiated areas of responsibility for each healthcare provider in a region according to the level of care expertise with a special function for university medicine

providing adequate numbers of qualified medical and care staff

guaranteeing comprehensive digitisation and structured cross-sectoral connectivity of all hospitals and of ambulatory care

ensuring the realisation of healthcare tasks, for example by supplementing the current diagnosis related groups (DRG) reimbursement with structural components while avoiding false incentives

social appreciation, appropriate remuneration, attractive and needs-based training as well as favourable working conditions for medical and non-medical personnel

With this statement, the German National Academy of Sciences Leopoldina publishes the fourth ad-hoc-statement on the coronavirus pandemic in Germany. The publication is available at: http://www.leopoldina.org/en/coronavirus

The first three statements focused on acute healthcare policy measures in dealing with the pandemic, and on psychological, social, legal, educational, and economic measures that may contribute to a gradual return to societal normality. The corresponding documents can also be downloaded at: http://www.leopoldina.org/en/coronavirus

The Press and Public Relations Department will gladly provide suitable contacts. Please direct any enquiries to the e-mail address press@leopoldina.org or call +49 (0)345 / 472 39-800.

Urbanization could cause 26 percent more rain to fall over Jeddah city than over the surrounding desert during storms.

The coastal city of Jeddah, located on the Red Sea, has a population of around 4 million and is the commercial center of Saudi Arabia. Its main weather threat is winter storms that bring heavy rains, strong winds and flash flooding. In 2009, a severe storm in the city claimed 161 lives and caused 1 billion USD worth of damage; however, these potentially devastating storms are also an important source of water for the arid region.

"Saudi Arabia has a national plan to double rainfall harvesting by 2030 to address the water resource challenge," says Thang Luong, postdoctoral fellow from KAUST. Understanding how storms evolve over Jeddah could help the city better forecast future events, reduce damage and support the country's plans to collect the precious rainwater.

Like many cities, Jeddah experiences an urban heat island effect, whereby daytime heat absorbed by buildings and roads is slowly released at night. This can affect local weather, but it is not clear how or if Jeddah's heat island effect affects winter thunderstorms--although it appears that they occur mainly in the early morning.

Earth Science and Engineering Professor Ibrahim Hoteit, working with Luong and his team at KAUST, combined atmospheric and land surface models to simulate rainfall during 10 severe storms over Jeddah under urbanized and presettlement scenarios. In the urban scenario, they applied an urban canopy model to account for heat fluxes from rooftops, walls and roads as well as the wind-altering effect of streets and buildings. In the desert scenario, land cover was considered as barren or sparsely vegetated.

Jeddah experienced heavier and more prolonged rainfall under the urban scenario, suggesting that something was enhancing the storm's energy and blocking its passage. Heavy rainfall events brought about 26 percent more rainfall in the urbanized scenario than in the desert scenario. "We found that surplus energy stored in the urban surface early in the day can be released and make storms stronger at night," says Luong. The models showed rainfall decrease immediately downwind from the city, likely due to buildings disrupting airflow.

The well-documented 2009 flood provided an ideal test case, and the team found that their model accurately reproduced the observed precipitation. "These modeling capabilities are valuable tools for forecasting flash floods in Jeddah," says Hoteit, "and will help policy and planning for mitigating further damages from severe weather events."

A few unanswered questions remain. "We want to find out which elements of urban physics are the most critical in driving rainfall," says Luong, "and investigate what would happen to storm evolution if the urban area spread along the Red Sea coast."

The anaesthetic drug ketamine has been shown, in low doses, to have a rapid effect on difficult-to-treat depression. Researchers at Karolinska Institutet now report that they have identified a key target for the drug: specific serotonin receptors in the brain. Their findings, which are published in Translational Psychiatry, give hope of new, effective antidepressants.

Depression is the most common psychiatric diagnosis in Sweden, affecting one in ten men and one in five women at some point during their lives. Between 15 and 30 per cent of patients are not helped by the first two attempts at therapy, in which case the depression is designated difficult to treat. Studies have shown that low doses of the anaesthetic drug ketamine are rapid acting on certain sufferers, but exactly how it works is unknown. A nasal spray containing ketamine has recently been approved in the USA and EU for patients with treatment-resistant depression.

Researchers at Karolinska Institutet in Sweden have now imaged the brains of study participants using a PET (positron emission tomography) camera in connection with ketamine treatment.

"In this, the largest PET study of its kind in the world, we wanted to look at not only the magnitude of the effect but also if ketamine acts via serotonin 1B receptors," says the study's first author Mikael Tiger, researcher at the Department of Clinical Neuroscience, Karolinska Institutet. "We and another research team were previously able to show a low density of serotonin 1B receptors in the brains of people with depression."

In the first phase of the study, 30 people with difficult-to-treat depression were randomly assigned to either a ketamine-infusion group (20 individuals) or a placebo (saline) group. It was a randomised double-blind study, so neither patient nor doctor initially knew who received the active substance. The participants' brains were imaged with a PET camera before the infusion and 24-72 hours afterwards.

In the next phase, those who so wished (29 individuals) received ketamine twice a week for two weeks. The result was that over 70 per cent of those treated with ketamine responded to the drug according to a rating scale for depression.

Serotonin plays a key role in depression and low levels are thought to be linked to more serious disease. There are 14 different kinds of receptor for this neurotransmitter on the surface of neurons. For their PET imaging, the researchers used a radioactive marker that binds specifically to serotonin 1B receptors. They found that the ketamine operated via these receptors in a formerly unknown mechanism of action. Binding to this receptor reduces the release of serotonin but increases that of another neurotransmitter called dopamine. Dopamine is part of the brain's reward system and helps people to experience positive feelings about life, something that is often lacking in depression.

"We show for the first time that ketamine treatment increases the number of serotonin 1B receptors," says the study's last author Johan Lundberg, research group leader at the Department of Clinical Neuroscience, Karolinska Institutet. "Ketamine has the advantage of being very rapid-acting, but at the same time it is a narcotic-classed drug that can lead to addiction. So it'll be interesting to examine in future studies if this receptor can be a target for new, effective drugs that don't have the adverse effects of ketamine."

Scientists do not yet know if Severe Acute Respiratory Syndrome Coronavirus 2, or SARS-CoV-2 - the virus that causes COVID-19 - can be transmitted by blood transfusion. But given the unknowns around this new pathogen, researchers at Colorado State University used existing technologies to show that exposing the coronavirus to riboflavin and ultraviolet light reduces pathogens in human plasma and whole-blood products.

The study, "Pathogen reduction of SARS-CoV-2 virus in plasma and whole blood using riboflavin and UV light," was published May 29 in PLOS ONE.

Dr. Izabela Ragan, postdoctoral fellow in the Department of Biomedical Sciences at CSU, said the research team tackled one of the big questions about the novel coronavirus: If the pathogen can spread through blood or by donating blood, would it be possible to kill the virus?

"The research we conducted answers that question: yes, you can," said Ragan. "We eliminated a huge amount of virus and we could not detect the virus post-treatment."

The research team used the Mirasol Pathogen Reduction Technology System to treat nine plasma and three whole-blood products for the study.

The technology - which is owned by medical device company Terumo BCT - was invented by Ray Goodrich, senior author of the study and executive director of the Infectious Disease Research Center at CSU. He is also a professor in the Department of Microbiology, Immunology and Pathology.

Simple process

Dr. Heather Pidcoke, a co-author on the study and chief medical research officer at CSU, said the process used by the research team is quite simple.

The blood product or plasma is placed in a specially designed storage bag, riboflavin solution is added, and the mixture is then exposed to UV light. The Mirasol PRT device gently shakes the bag to circulate the blood cells, so the cells come to the surface where they are exposed to the UV light.

The authors caution that this is not an experiment to try at home. The light does not penetrate the entire bag, so it's not the same as exposing body parts to UV light.

Goodrich said the research may help to avoid what happened in the 1980s, when HIV was transmitted through blood and blood products while scientists were still trying to isolate and identify what might be causing the spread of the virus. However, he noted that the Mirasol system is currently only approved for use outside of the United States, mainly in Europe, the Middle East and Africa.

"Our research may help inform people outside the U.S who are using it," he said. "They may breathe a sigh of relief knowing that while we continue to study this, there is some potential mitigation in place just in case."

Studying transmission question

CSU researchers are currently studying whether SARS-CoV-2 is transmitted by blood. Ragan said they hope to answer that question very soon.

Advances in neuroscience research and microscopy: a collaborative project driven by researchers of the Max Perutz Labs Vienna, a joint venture of the University of Vienna and the Medical University of Vienna, and the TU Wien (Vienna) allows researchers to look deep into organs and nervous systems of animals, ranging from squids and worms to fish and salamanders.

Analyses of individual cells in the context of whole organs or tissues is becoming increasingly important in biology. A standard approach so far was to cut larger tissues into thin layers, study each of these sections, and then piece the information again together into a 3D model. However, this is a laborious process, and often yields incomplete results. For instance, the cells that make up our nervous systems possess long extensions that can reach through the entire body. Reconstructing such projections from small slices is extremely challenging.

An elegant solution to avoid this is provided by tissue clearing techniques that can render opaque tissues transparent. When applied to complex tissues, including the brain, such techniques allow to visualize individual cells and their extensions, enabling scientists to capture 3D images of cells and tissues without the need of sectioning. However, existing clearing techniques so far were not optimized to remove a variety of pigments that are present in tissues, and that limit how deeply these specimens can be imaged. Therefore, despite the power of tissue clearing approaches, they have essentially remained restricted to specific unpigmented organs like the brain, and a handful of model species that have reduced pigmentation.

In a team effort, researchers from the Max Perutz Labs, the Medical University of Vienna and the TU Wien (Vienna) and their collaborators have now developed a new method that combines tissue clearing with the removal of various pigment types as they are characteristic for most animals. This new approach - dubbed "DEEP-Clear" - has now been published in the international journal Science Advances.

A toolkit for imaging biomolecules in the nervous systems of a broad panel of species

An important observation that helped to develop the new method was that the combination of different chemical treatments had a synergistic effect, allowing for fast depigmentation and tissue clearing. "Shortening chemical processing preserves the integrity of tissues and organisms, so that the molecules and internal structures of interest are more likely to be retained", explains Marko Pende, the developer of the clearing method, from the lab of Hans-Ulrich Dodt at the TU Wien and the Center for Brain Research (CBR) of the Medical University of Vienna, and one of the first authors of the study. This way multiple organisms could be imaged from different clades ranging from mollusks to bony fish to amphibians. "These are just a few examples. We believe that the method is applicable to multiple organisms. It was just not tried yet", explains Prof. Hans Ulrich Dodt, senior author of the study.

The team then systematically explored which types of molecules could still be marked and detected in DEEP-Clear-processed samples, investigating species ranging from squids and worms to fish and salamanders. This work - largely performed by PhD student Karim Vadiwala in the lab of Florian Raible at the Max Perutz labs - showed that DEEP-Clear was compatible with the detection with a variety of important biomolecules, allowing to image specific proteins, DNA markers and RNA in intact specimens. "This versatility of DEEP-Clear makes it a highly attractive tool to explore a range of animals for which standard tissue clearing techniques currently would not be sufficient", explains Karim Vadiwala (Max Perutz Labs).

A 3D view of whole animal nervous systems to explore neural stem cell biology

Besides its compatibility with many species, another attractive feature of DEEP-Clear is that the transparency of the processed organisms allows to image samples across scales: On the one hand, the team looked into very small details such as contact points between neurons, or individual clusters of dividing cells. On the other hand, they took advantage of the latest generation of so-called light-sheet microscopes developed by the Dodt lab, in which two-dimensional laser light is used to rapidly scan a whole sample, resulting in a full three-dimensional model created on the computer. "Using a very thin light-sheet enables us to overcome a lot of optical limitations and allows us to generate such high-resolution images, even from samples that are several millimeters thick", says the designer of the microscopes, Dr. Saiedeh Saghafi (TU Wien).

The expectation of the team is that "DEEP-Clear" will serve to popularize tissue clearing, allowing researchers around the world to intensify molecular and cellular research in a variety of species that exhibit highly interesting, but poorly explored neuroscientific features. For instance, worms, fish, and salamanders can regenerate parts of their central nervous system, suggesting that they possess molecular capacities that humans and other mammals have lost. "Visualizing the responsible stem cells, and investigating their molecular make-up, or their contribution to regenerated tissue, will be greatly facilitated by DEEP-Clear", believes Dr. Florian Raible (Max Perutz Labs), who coordinated the study that also involved additional researchers in the groups of Dr. Oleg Simakov (Uni Vienna) and Dr. Elly Tanaka (Institute for Molecular Pathology).

WESTMINSTER, Colorado - MAY 29, 2020 - Scientists writing for the journal Invasive Plant Science and Management say several exotic grass species once grown in South Texas for livestock forage and erosion control have expanded from the areas where they were planted and have become invasive. They now are reducing the region's biodiversity and the habitats available for wildlife.

The problem species include King Ranch bluestem, Kleberg bluestem, Angelton bluestem, buffelgrass, guineagrass, Lehmann lovegrass, and Bermudagrass. In addition, the native grass tanglehead has begun displaying similar invasive behaviors.

The journal article explores the natural history of these grasses, their impact on diverse South Texas ecoregions and how they might be managed. Scientists say one important challenge is how to detect, assess and quantify the spread of invasive grasses growing over broad expanses.

Remote sensing technologies are playing an important role - including satellite imagery and unmanned aerial vehicles. Artificial intelligence and deep learning technologies are being used to interpret the data collected and inform more effective control practices.

"With further studies and fieldwork, we hope to have a roadmap that helps us understand the geology and ecology of invasive grasses in South Texas," says Justin P. Wied of Texas A&M University-Kingsville. "Conservationists and landowners will then have the tools they need to preserve and maintain the region's great natural landscapes."

A large international trial involving UCL and University College London Hospitals NHS Foundation Trust (UCLH) has found that pembrolizumab, a form of immunotherapy, more than doubled the 'progression free survival' time of patients with a specific subtype of advanced bowel cancer, when compared with chemotherapy.

'Progression free survival' is the length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease but it does not get worse. In a clinical trial, measuring the progression-free survival is one way to see how well a new treatment works.

As part of an interim analysis of clinical trial data, presented at the American Society of Clinical Oncology (ASCO) Annual Meeting, researchers found patients who were treated with pembrolizumab (also known as Keytruda) had 'progression-free survival' of 16.5 months (on average), compared with 8.2 months for those who were treated with chemotherapy.

In addition, 11% of patients who were treated with pembrolizumab were also found to have a 'complete response' where their disease had disappeared from scans. Furthermore, in almost half the patients who had pembrolizumab (48.3%), their disease had not progressed after two years versus only a fifth of patients who had had chemotherapy (18.6%), which means the beneficial effects are also durable.

The trial's UK Chief Investigator, Dr Kai-Keen Shiu, Honorary Associate Professor in Oncology at UCL Cancer Institute and Consultant Medical Oncologist at UCLH, said:

"This is the first randomised controlled study to show that first-line immunotherapy is significantly better than chemotherapy at shrinking metastatic bowel cancers with these specific DNA mutations, and delaying the time it takes for the cancer to progress.

"Whilst only around five per cent of advanced bowel cancer patients have these genetic mutations, they usually have a worse prognosis, and less response to chemotherapy and other targeted agents.

"The results from this trial really are game-changing and will almost certainly result in a paradigm shift in our current clinical practice."

The 'KEYNOTE-177' Phase III clinical trial, funded by Merck & Co (known as MSD in the UK), recruited 307 patients with metastatic bowel cancer, who had specific DNA mutations known as microsatellite instability high (MSI-H) or mismatch repair deficiency (dMMR).

These genetic alterations result in cells being unable to repair themselves correctly if damaged, and when this happens, errors in the DNA accumulate which may cause cancer. MSI-H/dMMR can be hereditary (also known as Lynch Syndrome) or sporadic, and affected patients usually have a poor prognosis when the disease has spread to other organs.

The randomised controlled trial recruited patients from 23 countries who were put into two equally sized groups. One group (or arm) of patients received pembrolizumab every three weeks for up to 35 cycles of treatment (up to approximately two years), while the other group received standard chemotherapy combinations with cancer targeting drugs bevacizumab or cetuximab (the chemotherapy arm) every two weeks.

Post-treatment results

For patients treated with pembrolizumab, progression-free survival was 55.3% at 12 months and 48.3% at 24 months. This compared with 37.3% and 18.6% respectively, for those on chemotherapy.

On average patients treated with pembrolizumab had a progression free survival of 16.5 months, compared with 8.2 months of chemotherapy - an improvement of 8.3 months.

11% of patients receiving pembrolizumab had a complete response (no detectable cancer), compared to 3.9% on chemotherapy.

32.7% of patients on pembrolizumab had a reduction in tumour size (partial response), compared to 29.2% on chemotherapy.

And 30.9% of patients on pembrolizumab had stable disease compared with 42.2% on chemotherapy*.

Response with pembrolizumab was also longer lasting, with 83% of patients having a response longer than 2 years, compared with 35% of patients receiving chemotherapy.

Severe treatment-related adverse events were also less common with pembrolizumab, 22%, whereas with chemotherapy this is 66%.

UCLH was one of the largest recruiters of patients for the trial with 18 participants from across England and 10 patients received pembrolizumab as first-line treatment.

Dr Shiu added: "The results of the KEYNOTE 177 trial have been keenly awaited by patients, clinicians and scientists alike. It is very encouraging that the side effects of pembrolizumab are significantly less than with chemotherapy, so not only the quantity but also the quality of life of these patients is better on immunotherapy.

"Some of my trial patients had a complete response to this therapy, are very well and have now been in remission for more than three years.

"There is ongoing collaborative research at UCL, UCLH and our research partners to further our understanding of why some patients benefit so much from immunotherapy whilst others do not."

Pembrolizumab is a type of immunotherapy known as a check-point inhibitor and helps make cancer cells more vulnerable to attack by your body's own immune system. It does this by blocking the activity of a molecule called PD-1, thereby allowing T cells (white blood cells that help your body fight disease) attack and kill tumours as they should.

Lead author Professor Thierry André, of the University of Sorbonne, France, said: "Pembrolizumab works in non-randomised studies in this group of patients with advanced disease. This randomised study demonstrates a huge benefit in first line with pembrolizumab and should be the new standard of care."

*These stability figures are accurate. Patients receiving immunotherapy usually either respond well and/or stabilise disease but then their disease does not usually progress or relapse for a long time. Patients on chemotherapy are less likely to have good responses but more disease stabilisation. However, in the majority of all cases, the effect of chemotherapy doesn't last as long unlike the durable benefits of immunotherapy.

Tree roots have multiple essential functions for their growth and survival. Acquiring nutrients and water from the soil, storing food and anchoring the plant in a substratum are what keep plants alive. In addition, root traits adapt themselves to physical limitation: they grow longer and thinner in dry soils in order to seek faraway water and they stay shorter in compact soils. Thanks to these powers, roots are an important pillar in tree survival strategy.

If root traits reflect and respond to soil characteristics, the study on variations of these traits will help to predict forest responses to global changes, including soil contamination. In search of the main tendencies in the variation of root traits, the professor at the Department of Botany, Ecology and Plant Physiology worked along with research staff at the Institute of Natural Resources and Agrobiology of Seville (part of the Spanish National Research Council) and the University of Seville. The study focused on the variation of 27 root traits (morphological, chemical and isotopic) in seven tree species planted in the Guadiamar Green Corridor in the province of Seville, an area with residual contamination from heavy metals after the accidental spill from the Aznalcóllar mines 22 years ago.

In this study, soil conditions and metal contamination affected root traits. The main tendency of the variation in root traits supports the "root economics spectrum" hypothesis, according to which trees that grow in favorable environments develop longer and lighter roots to maximize resource acquisition, while trees that grow in adverse environments develop shorter, denser roots, in order to use fewer resources. In this sense, contamination fosters the adjustment of a plant's root traits, with shorter roots being found in contaminated soils.

The study also concludes that there generally is coordination between roots and leaves. The rapid acquisition of water and nutrients via the roots is in agreement with a fast carbon capture and process via the leaves. However, a significant discrepancy between roots and leaves when processing trace elements was found (trace elements being pollutants such as arsenic, lead and cadmium).

These toxic elements get trapped in root cells and are not transferred to the leaves, becoming immobilized in the root. Thus, planting these Mediterranean species could have greater phytostabilization power, removing heavy metals from the soil they contaminate.

Toxic versions of the protein tau are believed to cause death of neurons of the brain in Alzheimer's disease. A new study published in Nature Communications shows that the spread of toxic tau in the human brain in elderly individuals may occur via connected neurons. The researchers could see that beta-amyloid facilitates the spread of toxic tau.

The present study is a collaboration between Lund University in Sweden and McGill University in Canada, and provides information on how toxic tau spreads in the human brain.

"Our research suggests that toxic tau may spread across different brain regions through direct neuronal connections, much like infectious diseases may spread to different cities through different transportation pathways. The spread is restricted during normal aging, but in Alzheimer's disease the spread may be facilitated by beta-amyloid, and likely leads to widespread neuronal death and eventually dementia," says lead author Jacob Vogel from McGill University.

"I think these findings have implications for therapies aiming at stopping the spread of tau and thereby halting the disease progression in Alzheimer's," says Oskar Hansson, professor of neurology at Lund University and co-lead investigator of the study.

There are two proteins that are known to be linked to Alzheimer's disease - beta-amyloid, which forms what is known as a plaque in the brain, and tau, which forms tangles within brain cells. Previous studies have linked the spread of toxic tau, in particular, to degeneration of the brain and symptoms such as memory impairment.

Intense research is ongoing to better understand how toxic tau spreads in the brain, in order to develop new therapies that can stop the spread and thereby stop the disease. Ongoing clinical trials are currently evaluating whether antibodies developed to bind to tau might stop the disease.

"Our findings have implications for understanding the disease, but more importantly for the development of therapies against Alzheimer's, which are directed against either beta-amyloid or tau. Specifically, the results suggest that therapies that limit uptake of tau into the neurons or transportation or excretion of tau, could limit disease progression," says Oskar Hansson.

Scientists from Far Eastern Federal University (FEFU) in collaboration with colleagues from the Institute of Chemistry FEB RAS come up with a smart technology for the synthesis of sorbent based on a "tungsten bronze" compound powder (Na2WO4) aimed to purify industrial and drinking water from hazardous radionuclides cesium (137Cs), and strontium (90Sr), as well as for effective processing of liquid radioactive waste. A related article appears in the Journal of Materials Science.

The new sorbent is appropriate when the concentration of hazardous radioactive elements is extremely higher than the acceptable level, i.e. for processing of liquid radioactive waste from nuclear plants and to eliminate the consequences of technological accidents.

The development resolves one of the pressing problems of modern radioecology, which is to completely or down to the level of regulative standards extract the hazardous radioactive elements cesium (137Cs) and strontium (90Sr) capable of accumulating in the body, replacing potassium and calcium.

The waste sorbent is supposed to convert into high-density ceramics with subsequent safe disposal.

"We propose to apply a sorbent in several ways. First, in the static version, granules based on tungsten bronze powder can simply be introduced into the volume of contaminated water bodies. Second, in a dynamic mode, porous sorbent tablets can be a component of flow filters. The high filtration efficiency registered by calculation methods determining the residual amount of radionuclides in sorbent-purified solutions, as well as the number of radionuclides retained in the sorbent body. We appreciate the Institute of Chemistry FEB RAS for the partial development of these methods in the frame of state assignment. We have studied physicochemical properties of the sorbent material via high-class Shimadzu equipment (Japan) and do believe that the operational properties of the material are up to analogs produced by more expensive technologies. Thus, we hope that our synthesis method will be recognized by the industry as most practical and technologically effective," says Arthur Drankov, a member of the creative team, postgraduate student of FEFU School of Natural Science.

The scientist points out that, if regenerated, the sorbent can serve five or more cycles. However, re-using of "tungsten bronze" sorbents is not the main idea, given that its absorbing abilities with respect to 137Cs and 90Sr radionuclides are well known.

The advantage proposed by researchers of FEFU School of Natural Science and FEB RAS is to convert waste granules or sorption tablets to high-density ceramics for further safe disposal during the half-life of hazardous radioactive elements. For cesium, this period is about 30 years, for strontium is about 29 years.

Scientists will develop a transforming-to-ceramics technology at the next stage of the work supported by a grant of the Russian Foundation for Basic Research (Grant chief is I. G. Tananaev, Director of FEFU School of Natural Science, corresponding member of the Russian Academy of Sciences).

Researchers suggest that the total outcome will be a cost-effective technology that guarantees environmental safety when dealing with radioactive waste.

Researchers at the University of Maryland, Baltimore County (UMBC) have developed a method to investigate the quality of healthcare data using a systematic approach, which is based on creating a taxonomy for data defects thorough literature review and examination of data. Using that taxonomy, the researchers developed software that automatically detects data defects effectively and efficiently.

The research is published in the Journal of the American Medical Informatics Association (JAMIA), and is led by Günes Koru, FAMIA, professor of information systems, and Yili Zhang, a former graduate student in Koru's lab who is now a postdoctoral fellow at Northwestern University. The paper stresses that the prevalence of defects in some of the existing healthcare data can be quite high. This must be addressed to better leverage the data to improve the quality of care, reduce costs, and achieve better healthcare outcomes. The team collaborated with an anonymous healthcare organization using real healthcare datasets.

Though many researchers today are involved in the analysis of healthcare data and are invested in its importance, there is very little research being done on the quality of the data being analyzed. Ultimately, this creates a far-reaching problem because important findings from the data may be less meaningful than assumed unless significant effort and money can be invested to deal with data quality problems with ad-hoc methods. For instance, much of the data that Koru's team analyzed contained errors of duplication, mismatched formatting and incorrect syntax.

Identifying these defects in healthcare data is deeply important when it comes to healthcare facilities providing essential services. Koru explains how healthcare facilities use the data collected. Healthcare organizations must "improve upon their services based on that data, and collect more data. If we can keep this cycle going, we can actually learn and improve more quickly, which is the main idea behind the concept of Learning Health Systems, and doing so is all the more important in the COVID-19 era," he says.

In the last decade, healthcare providers in the U.S. made a large leap from keeping patient records on paper to containing all patient information in computerized databases. This jump is significant because of the opportunity it provides for analysis, but researchers are still trying to learn how to effectively leverage the data as an asset.

Koru positions his team's research on data quality as being between the fields that are working to leverage data and the fields that are working to generate it. If the data itself--the bridge that connects the two fields--contains many inconsistencies and problems, then the relevant information cannot be used to provide better outcomes for patients and facilities.

In the future, Koru will continue to work with the partner facility's healthcare professionals to build a path forward. He will collaborate further to improve the quality of data and sustain an operation that bases much of its success on the data that it can gather from health services. His team will work with healthcare administration professionals when the software tools developed through this research are adopted in organizational settings to ensure the usability and usefulness of the tools.

"The taxonomy will help data stewards to identify, understand, and manage potential data quality problems in their future work," says Zhang.

Now more than ever, healthcare facilities are relying on strong data to support patients and the healthcare field as a whole. Koru and Zhang have found that collaborations between data researchers and healthcare organizations can generate effective solutions to the problem of data quality improvement.

Two University of Cincinnati students have developed an interactive dashboard which shows COVID-19 cases and deaths in Greater Cincinnati and other major U.S. cities. Known as the COVID-19 Watcher, it joins a list of options available to the public to track the novel coronavirus.

Benjamin Wissel, a student in the UC College of Medicine’s Medical Scientist Training Program, and Pieter-Jan Van Camp, MD, a doctoral student in the Biomedical Informatics Graduate program, developed their app during the spring when there were no options for tracking city data. Since then the New York Times has added this feature to their dashboard as well.

“People are connected and viruses spread through city infrastructures,” says Wissel. “Our app is especially relevant in places like Cincinnati, whose metro area is split between three different states. The public benefits from additional sources that can provide up-to-date COVID-19 data for the country, state, county and city level.”

Wissel and Van Camp published research on their dashboard recently in the Journal of the American Medical Informatics Association. Their dashboard is also listed on the Centers for Disease and Prevention Control website under the heading Cincinnati Children’s Hospital’s COVID-19 Watcher.

The COVID-19 Watcher displays data from every county and 188 metropolitan areas in the country. Features of the dashboard include ranking of the worst affected areas and auto-generating plots that depict temporal changes in testing capacity, cases and deaths. The COVID-19 Watcher can provide the public with real-time updates of outbreaks in their area.

“The New York Times has been tracking COVID-19 since January, and they released their data to the public in late March of this year,” says Wissel. “Our app pulls in their data, merges it with sources from the U.S. Census Bureau to map cases for each county to metropolitan areas, and then visualizes the data.”

Wissel says users of the dashboard can compare their city with others.

“Outbreaks started at different times in different cities, so it is insightful to compare the progression of the virus spreading in your city compared to other cities who started before you,” explains Wissel. “It is very hard to think of things in terms of exponential growth, but seeing case numbers from a city that is, for example, five days ahead of you can give you an idea of where your city might be in five days.”

Van Camp says users can explore the interactive dashboard’s possibilities.

“I think one of the dashboard’s more interesting features is the option to adjust the data by the size of the population per capita,” says Van Camp. “This way, you can compare the outbreak in different regions, regardless of high or low population, on a relative scale.”

Other co-authors on research include Michal Kouril, PhD, UC assistant professor of pediatrics and Cincinnati Children’s researcher; Chad Weis, senior systems analyst at Cincinnati Children’s; Tracy Glauser, MD, UC professor of pediatrics and associate director of the Cincinnati Children's Research Foundation; Peter White, PhD, adjunct professor of biomedical informatics at UC; Isaac Kohane, MD, PhD, chair of the Department of Biomedical Informatics Harvard Medical School; and Judith Dexheimer, PhD, UC associate professor of pediatrics and Cincinnati Children’s researcher.

Journal

Journal of the American Medical Informatics Association