Tech

Multicolour electrochromic displays are one of the most versatile applications because they can retain their coloured states without the need to supply electrical power. However, the simultaneous colouration of the counter layer when operating a conventional electrochromic display restricts the colour overlay effects. Additionally, the operation of conventional electrochromic displays requires external voltages to trigger the colouration/bleaching processes, which makes the conventional electrochromic displays far from a net-zero energy consumption technology.

In a new paper published in Light Science & Application, a team of scientists, led by Professor Abdulhakem Y. Elezzabi and Dr. Haizeng Li from Ultrafast Optics and Nanophotonics Laboratory, Department of Electrical and Computer Engineering, University of Alberta, Canada, and co-workers have developed a novel concept for transparent multicolour electrochromic displays by employing sodium ion stabilized vanadium oxide (SVO) nanorods as the electrochromic material. The SVO nanorods are compatible with a simple bar-coating method for fabricating electrochromic films when mixed with cellulose (Fig. 1a). Due to the oxidation nature of SVO, the added cellulose can be fully decomposed under a low temperature (200 °C) to prevent its influence on the conductivity.

The SVO film exhibits reversible multicolour switching (orange ? yellow ? green) during the Zn2+ insertion (self-colouring/discharging) and extraction (bleaching/charging). By taking advantage of the three-colour (orange ? yellow ? green) electrochromic response of the SVO film, an electrochromic display was constructed by sandwiching zinc foil between two SVO electrodes (Fig. 1b). This display enables independent operation of top and bottom electrochromic electrodes, thus providing additional configuration flexibility of the devices through the utilization of dual electrochromic layers under the same or different colour states (Fig. 1c). As such, the colour overlay effect can greatly broaden the colour palette. Using the colour overlay effect, the constructed Zn-SVO electrochromic display shows switching between the multiple colours (orange, amber, yellow, brown, chartreuse and green) while maintaining semitransparency of >30% (Fig. 1d).

More interestingly, the Zn-SVO electrochromic display possesses an open-circuit potential (OCP) of 1.56 V (Fig. 1e), which enables a self-colouration behaviour and energy retrieval functionality. This OCP stems from the redox potential difference between the zinc foil and the SVO electrode, which provides the driving force that activates oxidation of Zn (i.e., stripping of Zn into the electrolyte) and reduction of the SVO film (i.e., intercalation of Zn2+ into SVO). Thus, the built-in voltage allows the display to switch its colour from orange to green (including the four intermediate colours) due to the reduction of the SVO film while powering an LED (Figs. 1f, g).

These key properties mark a significant improvement over reported electrochromic displays, making the Zn-SVO electrochromic displays promising for switchable optical filters, electrochromic tuneable micro-optics, and transparent displays. This study represents a new paradigm in electrochromic displays that can potentially facilitate new opportunities for the development of high transparency, high energy efficiency, and large-area multicolour displays.

Cuba's successful containment of COVID-19 through door-to-door screening of every home in the country, shows how 'shoe-leather' epidemiology could have averted the dramatic failure of the UK's response to the pandemic. In Cuba there have been 2,173 confirmed cases and 83 deaths, with no reported deaths throughout the first week in June.

The term 'shoe leather' epidemiology, where much of the work is carried out on foot in the community, was first demonstrated during the Soho cholera epidemic in 1854.

Writing in the Journal of the Royal Society of Medicine, Professor John Ashton describes how, when China first reported the emerging epidemic in Wuhan in January 2020, Cuba promptly drew up a cross-government contingency plan. When the first cases of the virus were confirmed in the country among three tourists from Italy on 11 March, the plan was immediately put into action.

Screening was carried out in Cuba by tens of thousands of family doctors, nurses and medical students on foot, with testing, tracing and quarantining of suspected cases in state-run isolation centres for 14 days.

Prof Ashton said: "Cuba has long been renowned for its ability to turn in world beating health statistics while continuing to struggle economically. With a health system grounded in public health and primary care, the country invests heavily in producing health workers who are primarily trained to work in the community. Their efforts with COVID-19 have been outstanding."

He added: "Cuba was one of the first countries to send health workers to support the control of the epidemic in Wuhan, back in January, just one example of its unrivalled commitment to international solidarity in humanitarian disasters."

An increase of 20 to 30 per cent of invasive non-native (alien) species would lead to dramatic future biodiversity loss worldwide. This is the conclusion of a study by an international team of researchers led by Franz Essl and Bernd Lenzner from the University of Vienna. It has been published in the journal Global Change Biology.

Human activities intentionally and unintentionally introduce more and more plant and animal species to new regions of the world - for example, via commodity transport or tourism.

Some of these alien species have negative consequences for biodiversity and humans well-being, for example by displacing native species or transmitting diseases. However, while we have relatively good information on the historical spread of alien species, there is still little knowledge about their future development.

"At the moment it is not yet possible to generate precise predictions based on computer models as to how the spread and impact of alien species will change in the future. Therefore, expert assessments via standardised surveys are an important tool to obtain a better understanding of the causes and consequences of the spread and impact of alien species for the coming decades," says Franz Essl.

The study shows that an increase of 20 to 30 per cent in the number of newly introduced alien species is considered sufficient to cause massive global biodiversity loss - a value that is likely to be reached soon, as the number of introduced species is constantly increasing.

Climate change and trade drive increase

Furthermore, humans are the main driver of the future spread of alien species. The experts identify three main reasons, primarily the increasing global transport of goods, followed by climate change and then the impacts of economic development such as energy consumption and land use. The study also shows that the spread of alien species can be greatly slowed down by ambitious countermeasures.

The researchers additionally investigated the influence of the increase of alien species on different regions of the world: For example, tourism is a major driver of biological invasions in tropical and subtropical regions, while climate change favours the survival and establishment of alien species in the future, especially in polar and temperate regions.

"Our study illustrates the option space we currently have to reduce the future impacts of alien species," says Bernd Lenzner.

"The results form an important scientific basis for the further development of international agreements such as the Sustainable Development Goals or the Convention on Biological Diversity. This way we will be able to reduce the negative impacts of alien species on global biodiversity and our society."

The study involved 38 researchers from across Europe, North and South America, New Zealand and South Africa.

Helen Roy of the UK Centre for Ecology & Hydrology, one of the co-authors, says: "There has been a rapid escalation in the number of non-native species being transported and introduced by humans around the world; the adverse effects of some of these so called invasive non-native species on biodiversity and ecosystems has been extensively documented.

"It is now critical that we work collaboratively to predict future patterns so that we can inform appropriate action going forward - such as improved biosecurity to prevent further introductions of the most damaging invasive non-native species."

An interdisciplinary team of scientists studying thousands of oyster shells along the Georgia coast, some as old as 4,500 years, has published new insights into how Native Americans sustained oyster harvests for thousands of years, observations that may lead to better management practices of oyster reefs today.

Their study, led by University of Georgia archaeologist Victor Thompson, was published July 10 in the journal Science Advances.

The new research argues that understanding the long-term stability of coastal ecosystems requires documenting past and present conditions of such environments, as well as considering their future. The findings highlight a remarkable stability of oyster reefs prior to the 20th century and have implications for oyster-reef restoration by serving as a guide for the selection of suitable oyster restoration sites in the future.

Shellfish, such as oysters, have long been a food staple for human populations around the world, including Native American communities along the coast of the southeastern United States. The eastern oyster Crassostrea virginica is a species studied frequently by biologists and marine ecologists because of the central role the species plays in coastal ecosystems.

Oyster reefs are a keystone species that provide critical habitats for other estuarine organisms. Oyster populations, however, have dramatically declined worldwide over the last 100 years due to overexploitation, climate change and habitat degradation.

"Oyster reefs were an integral part of the Native American landscape and our study shows that their sustainability over long periods of time was likely due to the sophisticated cultural systems that governed harvesting practices," said Thompson, professor of anthropology in the Franklin College of Arts and Sciences and director of the UGA Laboratory of Archaeology.

According to Thompson, prior models used by archaeologists have not adequately accounted for the role Indigenous people had not only sustaining ecosystems, but also enhancing biodiversity.

"Our research shows that harvesting was done likely with an aim towards sustainability by Native American communities," he said. "Work here along the Georgia coast, along with colleagues working in the Pacific and in Amazonia, indicates that Indigenous peoples had a wealth of traditional ecological knowledge regarding these landscapes and actively managed them for thousands of years."

Changes in oyster shell size and abundance is widely used to examine human population pressures and the health of oyster reefs. The researchers measured nearly 40,000 oyster shells from 15 Late Archaic (4500 - 3500 years Before Present) through Mississippian (1150 - 370 years BP) period archaeological sites situated along the South Atlantic coast of the United States to provide a long-term record of oyster harvesting practices and to document oyster abundance and size across time.

The new findings show an increase in oyster size throughout time and a nonrandom pattern in their distributions across archaeological sites up and down the coastline that the authors believe is related to the varying environmental conditions found in different areas.

When the researchers compared their work to maps of the 19th-century oyster reef distributions, they found that the two were highly correlated. All of the data on oyster size and reef size suggested there was considerable stability in oyster productivity over time, even if some reefs were not quite as productive as others. This overall productivity changed, however, in the early 1900s when industrial oyster canning devastated the reefs, leaving only a small percent of the reefs viable today.

"This work, which was partially supported by the Georgia Coastal Ecosystems Long Term Ecological Research project, demonstrates the importance of understanding the role that humans play in shaping the landscape, and that is something that is not always appreciated in ecological studies," said Merryl Alber, professor and director of the UGA Marine Institute on Sapelo Island, a site of excavations for this study.

Aromatic esters are chemicals that contain an aromatic ring consisting of functional groups called esters. These organic compounds are widely used as chemical feedstock in industries like food and beverages, pharmaceuticals, and cosmetics. Thus, finding efficient reactions for their synthesis is an important area of research in organic chemistry. In the petroleum industry, chemists use a unique reaction called aromatic isomerization for the synthesis of aromatic compounds, in which the functional group (mainly hydrocarbon) on the carbon atom in the starting material migrates to another carbon atom on the aromatic ring. But, this reaction requires harsh conditions, and thus, there are considerable doubts regarding its sustainability.

To overcome this limitation, researchers at Waseda University, Japan, led by Professor Junichiro Yamaguchi, attempted to produce fine-grade aromatic esters using milder reactions, in a study published in Science Advances. The scientists derived their inspiration from another reaction, called the halogen dance reaction, in which a halogen substituent is translocated to another carbon atom on the aromatic ring and is often used in total synthesis of complex natural products. They wanted to find out if a similar reaction could be developed for esters too. But, this was no mean feat, as it is not easy to make the ester group change its position from one ring carbon to another under mild conditions. Luckily, the researchers' previous experiments with ester transformation reactions had revealed that this was possible, although this reaction was not yet optimized. Yamaguchi says, "During our recent efforts in the development of decarbonylative transformations of aromatic esters, we unexpectedly discovered an aromatic compound with ester translocated from one carbon to another carbon. After optimizing the conditions, we were able to develop a new reaction, which we discovered by chance."

The trick to developing this new reaction was a palladium catalyst consisting an easy-to-handle diphosphine ligand called dcypt, developed by the scientists. When the scientists tested this new catalyst, they were surprised by the reaction, which resulted in the ester group successfully being translocated on the aromatic ring--a finding that was unprecedented. The researchers named the process as "ester dance reaction," owing to the ability of ester groups to "dance" around the aromatic ring. Discussing their achievement, Yamaguchi says, "In one of our experiments involving transformations of aromatic esters, we found that our 'home-made' catalyst can enable a difficult conversion reaction. This was an exciting new discovery.''

The researchers then went on to optimize the conditions for this reaction, in an effort to make it as efficient as possible. At first, the product was obtained at a low yield. But the researchers did not give up. Their experiments found appropriate concentrations of a palladium salt, dcypt, and a chemical reagent called potassium carbonate under optimal conditions, which resulted in a product yield as high as 85%. They also found that these three reagents were critical for the reaction to occur. With these optimized reaction conditions, the scientists explored this new ester dance reaction in other aromatic substances, such as phenyl benzoates, heteroarenes, and other aromatics. They found that combining this reaction with other ester-transforming reactions, such as arylation, amination, and etherification, produced compounds with an array of different substitution patterns. Interestingly, some derivatives of the products were much costlier than the starting material, meaning that this was an overall cost-efficient process. Furthermore, they successfully obtained a 1,3-translocation product to demonstrate a combination of the
double ester dance and decarbonylation.

With the novel catalyst developed by the researchers and the optimized catalytic reaction, synthesizing aromatic compounds sustainably can now become easier. Yamaguchi concludes, "We believe that our unconventional yet predictable approach of using the 'ester dance reaction' will help the organic chemist synthesize aromatic compounds that are usually difficult and expensive to create.''

Cell phone batteries often heat up and, at times, can burst into flames. In most cases, the culprit behind such incidents can be traced back to lithium batteries. Despite providing long-lasting electric currents that can keep devices powered up, lithium batteries can internally short circuit, heating up the device.

Researchers at Texas A&M University have invented a technology that can prevent lithium batteries from heating and failing. Their carbon nanotube design for the battery's conductive plate, called the anode, enables the safe storage of a large quantity of lithium ions, thereby reducing the risk of fire. Further, they said that their new anode architecture will help lithium batteries charge faster than current ¬¬commercially available batteries.

"We have designed the next generation of anodes for lithium batteries that are efficient at producing large and sustained currents needed to quickly charge devices," said Juran Noh, a material sciences graduate student in Dr. Choongho Yu's laboratory in the J. Mike Walker '66 Department of Mechanical Engineering. "Also, this new architecture prevents lithium from accumulating outside the anode, which over time can cause unintended contact between the contents of the battery's two compartments, which is one of the major causes of device explosions."

Their results are published in the March issue of the journal Nano Letters.

When lithium batteries are in use, charged particles move between the battery's two compartments. Electrons given up by lithium atoms move from one side of the battery to the other. On the other hand, lithium ions travel the other direction. When charging the battery, lithium ions and electrons go back to their original compartments.

Hence, the property of the anode, or the electrical conductor that houses lithium ions within the battery, plays a decisive role in the battery's properties. A commonly used anode material is graphite. In these anodes, lithium ions are inserted between layers of graphite. However, Noh said this design limits the amount of lithium ions that can be stored within the anode and even requires more energy to pull the ions out of the graphite during charging.

These batteries also have a more insidious problem. Sometimes lithium ions do not evenly deposit on the anode. Instead, they accumulate on the anode's surface in chunks, forming tree-like structures, called dendrites. Over time, the dendrites grow and eventually pierce through the material that separates the battery's two compartments. This breach causes the battery to short circuit and can set the device ablaze. Growing dendrites also affect the battery's performance by consuming lithium ions, rendering them unavailable for generating a current.

Noh said another anode design involves using pure lithium metal instead of graphite. Compared to graphite anodes, those with lithium metal have a much higher energy content per unit mass or energy density. But they too can fail in the same catastrophic way due to the formation of dendrites.

To address this problem, Noh and her teammates designed anodes using highly conductive, lightweight materials called carbon nanotubes. These carbon nanotube scaffolds contain spaces or pores for lithium ions to enter and deposit. However, these structures do not bind to lithium ions favorably.

Hence, they made two other carbon nanotube anodes with slightly different surface chemistry -- one laced with an abundance of molecular groups that can bind to lithium ions and another that had the same molecular groups but in a smaller quantity. With these anodes, they built batteries to test the propensity to form dendrites.

As expected, the researchers found that scaffolds made with just carbon nanotubes did not bind to lithium ions well. Consequently, there was almost no dendrite formation, but the battery's ability to produce large currents was also compromised. On the other hand, scaffolds with an excess of binding molecules formed many dendrites, shortening the battery's lifetime.

However, the carbon nanotube anodes with an optimum quantity of the binding molecules prevented the formation of dendrites. In addition, a vast quantity of lithium ions could bind and spread along the scaffold's surface, thereby boosting the battery's ability to produce large, sustained currents.

"When the binding molecular groups are abundant, lithium metal clusters made from lithium ions end up just clogging the pores on the scaffolds," said Noh. "But when we had just the right amount of these binding molecules, we could 'unzip' the carbon nanotube scaffolds at just certain places, allowing lithium ions to come through and bind on to the entire surface of the scaffolds rather than accumulate on the outer surface of the anode and form dendrites."

Noh said that their top-performing anodes handle currents five times more than commercially-available lithium batteries. She noted this feature is particularly useful for large-scale batteries, such as those used in electric cars, that require quick charging.

"Building lithium metal anodes that are safe and have long lifetimes has been a scientific challenge for many decades," said Noh. "The anodes we have developed overcome these hurdles and are an important, initial step toward commercial applications of lithium metal batteries."

How should one design porous carbon materials for advanced Li-S batteries cathodes? What electrolytes are extensively studied for high-safety Li-S batteries? In a paper published in NANO, a group of researchers from Qingdao, China have reviewed the recent progresses in sulfur/carbon cathode materials and high safety electrolytes towards advanced Li-S batteries. Some potential issues and possible developmental directions are also discussed.

Lithium-sulfur (Li-S) battery is one of the most promising secondary batteries for its high energy density, high natural abundance and environment-friendly nature of sulfur. However, the commercial application of Li-S battery faces some technical obstacles, such as low cycling stability resulted from the shuttle effect of polysulfides, low electrical conductivity of sulfur, and volume expansion during charge/discharge process. Furthermore, due to the flammability of organic solvents in liquid electrolytes, the continuous formation of lithium dendrites and the low ignition temperature of carbon-sulfur mixtures, the safety of Li-S batteries has become another critical issue to be solved.

In recent years, many different strategies have been put forward to improve the electrochemical performance and safety of Li-S batteries, containing the development of carbon/sulfur composite cathodes, design of flame retardant electrolytes and protection of negative electrodes. In this review, the challenges and trends of Li-S batteries are first discussed. The recent progress of sulfur/carbon composite cathode materials for Li-S battery is then introduced in detail. Then the evaluation methods and latest development of high-safety electrolytes towards advanced Li-S batteries are summarized. Finally, the development trends of Li-S battery are forecasted. Although some issues in Li-S batteries are still unknown or contradictory, its mysterious veil will be gradually revealed with further in-depth research.

Additional co-authors of the paper are Chen-Liu and Yue Gao from the SINOPEC Safety Engineering Institute, Jin-Mei Zhang and Ya-Qin Wang from the National Registration Center for Chemicals, Ministry of Emergency Management of the People's Republic of China.

For more insight into the research described, readers are invited to access the paper on NANO.

When a bicycle gets wet in the rain, the frame and chain become corroded or rusty which shorten the life of the bike. Oil needs to be regularly applied to prevent this from happening. Battery cells are devices that create electrical energy through moving electrons by triggering oxidation and reduction reactions separately. But they also corrode when exposed to oxygen. Can these cells also be greased to prevent rusting?

A research team led by Professor Yong-Tae Kim and doctoral student Sang Moon Jung of Materials Science and Engineering at POSTECH used a catalyst (Pt/HxWO3) that combines platinum and hydrogen tungsten bronze to solve the corrosion in fuel cells that occur when hydrogen cars are shut down. The catalyst, recently introduced in Nature Catalysis - a sister journal of Nature - has been shown to promote hydrogen oxidation and selectively suppress oxygen reduction reactions (ORR).

As eco-friendly hydrogen cars become more common, the race for research and development for improving fuel cell performance - the heart of hydrogen cars - is getting fierce around the world. The performance of automotive fuel cells are severely low owing to their intermittent shut-downs compared to power-generating fuel cells that do not stop once started. This is because when ignition is turned off, the ORR occurs as air is temporarily introduced into the anode, and corrosion of the cathodic components accelerates as the potential of cathod surges instantaneously.

The research team focused on the Metal Insulator Transition (MIT) phenomenon, which can selectively change the conductivity of materials depending on the surrounding environment, to solve the problem of durability degradation in automotive fuel cells.

n particular, the research team focused on the tungsten oxide (WO3) that has traditionally been used as an electrical discoloration material since it greatly changes conductivity via the insertion and reduction of protons. Applying the MIT phenomenon of WO3 in normal operation results in an electrode reaction while maintaining the H-WO3 (conductor) state with the insertion of a proton. In contrast, when ignition is shut-down, mixed air is drawn in which increases the oxygen pressure and changes it into WO3 (subconductor) which stops the electrode reaction, thus solving the issue of cathodic corrosion.

The Pt/HxWO3 selective hydrogen oxidation reaction (HOR) catalysts imparted by the metal-insulator transition phenomenon showed more than twice the durability of conventional commercial Pt/C catalyst materials in shut-down conditions in the MEA evaluation of automotive fuel cells.

Professor Yong-Tae Kim who led the research commented, "This research has dramatically improved the durability of automotive fuel cells." He added, "It is anticipated that the commercialization of hydrogen cars may be further facilitated through these findings."

The collaborators are Kazan Federal University, Vereschagin Institute of High Pressure Physics (Russian Academy of Sciences), Queen Mary University of London, Imperial College London, Rutherford Appleton Laboratory, Wuhan University of Technology, and Sichuan University.

Co-author, Chair of the Department of Computational Physics of Kazan Federal University Anatolii Mokshin explains, "The key difference between the liquid state of matter and the solid state is the presence of shear stiffness in solids. In other words, solids can retain their shape in contrast to liquids and gases, which take the shape of the vessels in which they are placed. Together with our foreign colleagues, we found out that such an understanding is not entirely correct. We were able to obtain experimental confirmation of the presence of shear stiffness in a liquid. And this means that on a spatial scale comparable to the size of molecules and atoms, a liquid exhibits elasticity and rigidity, like a solid. This is very surprising. In particular, a liquid at these extremely small scales will respond to external deformation influences like an ordinary solid. The results are obtained for the case of gallium melt. However, they are true for any fluid."

The uniqueness of this work, according to the interviewee, is that for the first time a comprehensive study was carried out, including experiments on inelastic neutron scattering, large-scale molecular dynamics calculations performed by the Kazan University computer cluster and the supercomputer of the Interdepartmental Supercomputer Center of the Russian Academy of Sciences, and a theoretical explanation in the framework of the original self-consistent relaxation theory of the liquid state.

"New data are important for understanding a number of fundamental scientific questions related to liquid state physics. They must be taken into account when designing nanodevices, nanostructures and metamaterials. Firstly, it is now possible to more accurately evaluate the physical parameters of liquids near the solidification temperature and the conditions (temperature and pressure) under which nanostructures can be constructed. Secondly, new possibilities have appeared for controlling liquids confined by nanometer-sized structures. One of the branches of modern physics, nanofluidics, is studying these issues," concludes Mokshin.

Researchers have developed a new pair of agents that show exceptional effectiveness for precision diagnosis and treatment of prostate cancer in preclinical studies. The agents, which target prostate-specific membrane antigen (PSMA), can be easily and economically synthesized without specialized equipment. This research was presented at the Society of Nuclear Medicine and Molecular Imaging's 2020 Annual Meeting on July 11-14.

PSMA is highly overexpressed in both primary and metastatic prostate cancer, making it a leading target for the development of radiopharmaceuticals. Iodine has several easily available isotopes with long half-life that can be used for single-photon emission computed tomography (SPECT), positron emission tomography (PET) or therapy. However, currently available radioiodinated PSMA-targeting radiopharmaceuticals require multiple steps for production, which reduces their yield and poses significant challenges for producing therapeutic doses.

To address this issue, researchers at Memorial Sloan Kettering Cancer Center (MSK) in New York, New York, developed the novel radioiodinated PSMA-targeting radiopharmaceutical 124/131I-MSK-PSMA1. "We were motivated by the fact that 131I is widely available, economical, can be used for diagnostic imaging and has demonstrated efficacy as a therapeutic agent. Our goal was to develop a radiopharmaceutical that can be produced very easily in high yields and high purity without requiring specialized equipment," said Dr. Kishore Pillarsetty, a radiochemist at MSK and senior author on the research. "124/131I-MSK-PSMA1 is the result of this search."

To demonstrate its efficacy, researchers synthesized 124/131I-MSK-PSMA1 and performed in vitro and in vivo studies. In vitro saturation binding assays were performed in prostate cancer cells, which were later harvested and counted for radioactivity using a gamma counter. In vivo PET imaging and biodistribution studies were performed on mice bearing prostate cancer xenografts.

The study indicates that 124/131I-MSK-PSMA1 can be produced in high yields without generating volatile byproducts, eliminating the need for high-pressure liquid chromatography purification. The in vitro and in vivo studies in prostate cancer cell and tumor xenograft models indicate high specificity, favorable pharmacokinetics and rapid clearance from non-target tissue.

"The exceptional tumor targeting and clearance from non-PSMA-expressing tissues make 124I-MSK-PSMA1 an excellent PET imaging agent and the corresponding 131I-MSK-PSMA1 a highly potent radiotherapeutic agent," said lead author Teja Muralidar Kalidindi, a senior research technician at MSK . "Because the diagnostic and therapeutic isotopes are chemically identical, we can precisely estimate the dose delivered to the tumor and other organs and personalize the dose to achieve the goals of precision medicine. We believe that 124/131I-MSK-PSMA1 has the potential to become part of the armamentarium available to the nuclear medicine and molecular imaging community for the diagnosis and treatment of metastatic castration-resistant prostate cancer patients."

Researchers are currently working with nuclear medicine clinicians to translate these findings into the first-in-human clinical trial for 124/131I-MSK-PSMA1. Additionally, the team plans to develop a kit formulation that will facilitate on-demand, onsite production to ensure that the radiopharmaceutical is available to the worldwide research community.

A new approach to functional bone imaging has established that bone metabolism is abnormally elevated in patients with knee osteoarthritis. This physiological information provides a new functional measure to help assess degeneration of the knee joint. The research was presented at the Society of Nuclear Medicine and Molecular Imaging 2020 Virtual Annual Meeting, July 11-14.

Osteoarthritis, the most common joint disorder in the United States, affects more than 32.5 million adults. It is marked by degradation and loss of soft tissues, such as cartilage, and development of bone marrow lesions and osteophytes. Osteoarthritis occurs most frequently in the hands, hips and knees and results in reduced productivity and quality of life.

"Osteoarthritis is not well understood, in part because we lack the tools to objectively evaluate early and reversible changes in key tissues," noted Lauren Watkins, MS, a researcher at the Stanford University Imaging of Musculoskeletal Function Group in Stanford, California. "While many MRI methods have been developed for assessment of early degenerative changes in cartilage, functional imaging of bone in the joint remains a major challenge."

To evaluate the relationship between structural and physiological changes in knee osteoarthritis, researchers utilized positron emission tomography (PET)/MRI with 18F NaF to image both knees of 12 subjects. Five subjects were scanned twice, with at least five days between visits, to assess repeatability of the technique. MRI Osteoarthritis Knee Score (MOAKS) assessment of each knee was performed by a trained musculoskeletal radiologist, and dynamic PET data were used to calculate the rates of bone perfusion, tissue clearance and mineralization, as well as tracer extraction fraction and total bone uptake rate. Kinetic modeling was performed for regions of interest representing the subchondral bone of the patella, medial and lateral tibia, and anterior, central, and posterior regions of the medial and lateral femur.

The knees with MOAKS findings were divided into regions of cartilage loss, bone marrow lesions and osteophytes and were analyzed along with the kinetic parameters derived from PET data. Abnormal bone metabolism in regions with bone marrow lesions, osteophytes, and adjacent cartilage lesions was found to be strongly associated with greater bone perfusion rates as compared to bone that appeared normal on MRI. Additionally, strong spatial relationships between bone metabolic abnormalities and changes in overlying cartilage were noted.

"These findings show the utility and potential of PET imaging to study the role of bone physiology in degenerative joint disease," said Watkins. "This knowledge may help us understand the order of events leading to structural and functional degeneration of the knee. Further, this will help us to develop and quickly evaluate new interventions that target specific metabolic pathways to give us the best chance to slow or arrest the onset and progression of osteoarthritis."

Whole body positron emission tomography (PET) has, for the first time, illustrated the existence of inter-organ communication between the heart and kidneys via the immune system following acute myocardial infarction, or heart attack. According to research presented at the Society of Nuclear Medicine and Molecular Imaging's 2020 Annual Meeting, the identification of a systemic inflammatory response to myocardial infarction has the potential to assist physicians in identifying patients most at risk of disease progression and most likely to respond to therapy.

Patients with acute myocardial infarction often develop impaired kidney function, thought to be mediated by the activation and mobilization of immune cells, or inflammation. While inflammation is necessary for effective healing, uncontrolled inflammatory cell activity can be detrimental for both the heart and the kidneys. To further understand the mechanics of this bidirectional interaction, researchers conducted a preclinical analysis of a novel imaging agent that targets inflammatory cells after myocardial infarction.

Using serial whole-body CXCR4-targeted 68Ga-pentixafor PET, researchers imaged 65 mice after surgically-induced myocardial infarction or sham surgery at one day, three days, seven days and six weeks. Tracer retention was determined in the kidneys and compared to infarct signal and cardiac function, as measured independently by magnetic resonance.

Cardiac CXCR4 signal was significantly elevated on the first day of imaging and returned to sham level after seven days. Renal CXCR4 signal was unchanged on the first day of imaging, but was reduced after seven days as compared to sham levels. Cardiac and renal signal were directly correlated, suggesting an inflammatory link between the heart and the kidneys. Ex-vivo autoradiography confirmed a significant correlation between tracer retention in the myocardial infarction region and the kidneys.

"This study provides a foundation for simultaneous examination of heart and kidneys after myocardial infarction by using molecular imaging," noted Rudolf Werner, MD, PhD, resident in the department of nuclear medicine at Hannover Medical School in Hannover, Germany. "It provides an impetus for the pursuit of systems-based multi-organ imaging to investigate systemic response to focal injury."

He continued, "Assessment of inflammation after myocardial infarction is beginning to be evaluated in clinical populations. With the growth of long-bore cameras with larger fields of view, the concept of multi-organ imaging will expand substantially in the next years.

In the future, nuclear medicine techniques may identify the optimal patient and time point for anti-inflammatory therapy, and identify the added risk to off-target organs after primary injury."

Ever smaller and ever more compact - this is the direction in which computer chips are developing, driven by industry. This is why so-called 2D materials are considered to be the great hope: they are as thin as a material can possibly be, in extreme cases they consist of only one single layer of atoms. This makes it possible to produce novel electronic components with tiny dimensions, high speed and optimal efficiency.

However, there is one problem: electronic components always consist of more than one material. 2D materials can only be used effectively if they can be combined with suitable material systems - such as special insulating crystals. If this is not considered, the advantage that 2D materials are supposed to offer is nullified. A team from the Faculty of Electrical Engineering at the TU Wien (Vienna) is now presenting these findings in the journal Nature Communications.

Reaching the End of the Line on the Atomic Scale

"The semiconductor industry today uses silicon and silicon oxide," says Prof. Tibor Grasser from the Institute of Microelectronics at the TU Wien. "These are materials with very good electronic properties. For a long time, ever thinner layers of these materials were used to miniaturize electronic components. This worked well for a long time - but at some point we reach a natural limit".

When the silicon layer is only a few nanometers thick, so that it only consists of a few atomic layers, then the electronic properties of the material deteriorate very significantly. "The surface of a material behaves differently from the bulk of the material - and if the entire object is practically only made up of surfaces and no longer has a bulk at all, it can have completely different material properties."

Therefore, one has to switch to other materials in order to create ultra-thin electronic components. And this is where the so-called 2D materials come into play: they combine excellent electronic properties with minimal thickness.

Thin layers need Thin Insulators

"As it turns out, however, these 2D materials are only the first half of the story," says Tibor Grasser. "The materials have to be placed on the appropriate substrate, and an insulator layer is also needed on top of it - and this insulator also hast to be extremely thin and of extremely good quality, otherwise you have gained nothing from the 2D materials. It's like driving a Ferrari on muddy ground and wondering why you don't set a speed record."

A team at the TU Wien around Tibor Grasser and Yury Illarionov has therefore analysed how to solve this problem. "Silicon dioxide, which is normally used in industry as an insulator, is not suitable in this case," says Tibor Grasser. "It has a very disordered surface and many free, unsaturated bonds that interfere with the electronic properties in the 2D material."

It is better to look for a well-ordered structure: The team has already achieved excellent results with special crystals containing fluorine atoms. A transistor prototype with a calcium fluoride insulator has already provided convincing data, and other materials are still being analysed.

"New 2D materials are currently being discovered. That's nice, but with our results we want to show that this alone is not enough," says Tibor Grasser. "These new electrically conductive 2D materials must also be combined with new types of insulators. Only then can we really succeed in producing a new generation of efficient and powerful electronic components in miniature format".

Microplastics (MPs), i.e., tiny plastic particles less than 5 millimeters in length, can now be found throughout the ocean and other aquatic ecosystems, and even in our seafood and salt. As MPs have become ubiquitous, scientists have become concerned about the transfer of MPs from the environment to the food chain and the potential impact of MPs on human health.

Scientists from the Chinese Academy of Sciences (CAS) recently found that microplastics are indeed contaminating edible plants, including vegetables we eat. The study was published in Nature Sustainability on July 13.

The study was led by LUO Yongming, a professor both at the Yantai Institute of Coastal Zone Research (YIC) and the Nanjing Institute of Soil Science of CAS.

Most MPs are emitted to the terrestrial environment and accumulate in large amounts in soil. In addition, secondary particles are formed by the degradation of plastics. Wastewater, an important source of water for agricultural irrigation, also contains small-sized MPs.

Despite the prevalence of MPs throughout the environment, the matter of MP uptake by crop plants has not received much attention.

For decades, scientists believed that plastic particles were simply too large to pass through the physical barriers of intact plant tissue. But this new study disproves this assumption.

"Cracks at the emerging sites of new lateral roots of lettuce and wheat crops can take in MPs from the surrounding soil and water. Those MPs can then be transferred from the roots up to the edible parts of the crop," said Prof. LUO.

Scientists already knew that particles as tiny as 50 nanometers in size could penetrate plant roots. But Prof. LUO's group revealed that particles about 40 times that size can get into plants as well.

The MPs identified in this study were spherical plastic particles up to 2 micrometers in size with a small degree of mechanical flexibility. These features allowed the MPs to squeeze into the small apoplastic space of plant root cells.

"Another mechanism is that at the lateral root emergence sites there are small cracks, and then the particles go through those cracks and enter the xylem vessels. Thus it is even possible that particles larger than the ones we studied might also be taken up by plants," said Dr. LI Lianzhen, first author of the study.

These findings shed new light on the possibility of food chain transfer of MPs. If MPs are getting into our crop plants, they are also getting into our meat and dairy. This raises obvious concerns about growing crops on fields contaminated with wastewater treatment discharge or sewage sludge, a process that could introduce MPs into the food chain. It also raises the key question of how MPs affect human health, a question for which there is as yet no clear answer.

Aside from the possible health impact, MPs in crops is also undesirable from the standpoint of agricultural sustainability.

A team, led by Dr. Jung-hoon Lee of the Computational Science Research Center of the Korea Institute of Science and Technology (KIST), recently collaborated with a team, led by Professor Jeffrey B. Neaton from the UC Berkeley Department of Physics, to develop a theoretical explanation for the structural changes and metallization that take place when hybrid (organic metal halide) Perovskite solar cells are exposed to external pressure. The explanation announced by the two teams is attracting much attention from related academic and industrial circles

Today, solar cells are not only used in our everyday lives, but are also used in extreme conditions such as atmospheric, space, desert, and maritime environments. Hybrid Perovskite solar cells (comprised of organic metals, halide (I) and lead (Pb): (CH3NH3)PbI3) are highly efficient and involve low production costs. These cells are promising, next-generation solar cells that can potentially be used to replace costly conventional silicon solar cells. Recognizing this potential, many researchers have been trying to engineer highly efficient hybrid Perovskite solar cell materials that are able to operate normally even in extreme conditions.

However, phase transition, from the *orthorhombic to **cubic structures, has been reported in hybrid Perovskite solar cells, when the cells are exposed to high external pressure. Metallization has also been reported, wherein electricity flows within the element and renders it unable to function properly. These changes under pressure have been major hurdles to the commercialization of the hybrid Perovskite solar cells. Hybrid Perovskite solar cells with modified structures and characteristics are unable to convert solar radiation into electric energy. This indicates that external pressure substantially deteriorates the performance of the solar cells. However, prior to this study, the cause of the deterioration, had not yet been clearly identified.

* Orthorhombic structure: In a rectangular prism, the three axes all have different lengths.
** Cubic structure: In a rectangular prism, the lengths of all three axes are the same.

The joint KIST-UC Berkeley research team used a supercomputer and quantum mechanical theory (***Density Functional Theory) to theoretically explain the pressure-induced structural changes (phase transition) and metallization in the hybrid Perovskite solar cells. By accurately predicting the phase transition pressure, the research team found that the cubic structure becomes more favorable for organic molecules than the original orthorhombic structure under high pressure, leading to the pressure-induced phase transition. Further, the research team theoretically demonstrated that the lead atoms in the hybrid Perovskite cells interact under high pressure, leading to metallization, which turns the solar cells into conductors and causes electricity to flow through them.

***Density Functional Theory: A quantum mechanical methodology used to calculate stable electron distributions and energies in materials.

The KIST-UC Berkeley is the first research team that has been able to identify the cause of the performance deterioration in hybrid Perovskite solar cells under external pressure. Dr. Jung-hoon Lee of the KIST is currently following up on the research by developing materials optimized for hybrid Perovskite solar cells. In particular, Dr. Lee is researching organic molecules that their stabilities are insensitive to different inorganic structures, and is looking for a replacement for the lead used in the cells, which is both the cause of the metallization and a major contributor to environmental destruction. Lee's research is expected to spur the development of next-generation solar cells that will eventually replace silicon solar cells.

"We expect that our study will provide new theoretical guidelines for the future development and optimization of high-performance hybrid Perovskite solar cells," stated Dr. Jung-Hoon Lee of the KIST. "We hope our results contribute to establishing hybrid Perovskite solar cells as a next-generation solar cell to replace silicon solar cells."