Earth

WASHINGTON -- Scientists and researchers at the U.S. Naval Research Laboratory and National Center for Advancing Translational Sciences (NCATS), submitted their findings to ACS Nano, a monthly peer-reviewed scientific journal, on their collaboration to develop SARS-CoV-2 nanoparticle probes that are used to study fundamental interactions between SARS-CoV-2 Spike proteins and human cells.

The manuscript, accepted on Aug. 18, is titled "Quantum Dot-Conjugated SARS-CoV-2 Spike Pseudo-Virions Enable Tracking of Host Cell Surface Angiotensin Converting Enzyme 2 Binding and Endocytosis." SARS-CoV-2 is known to attach to angiotensin converting enzyme 2 (ACE2) receptors via its external 'Spike' proteins, which cover the surface, which the virus uses to bind with and enter human cells.

"We developed nanoparticle-based pseudo-virions that bind to the host cell and track themselves inside of cells without being contagious," said Eunkeu Oh, Ph.D., an NRL biophysicist. "This opens an opportunity to expand the same strategy to various other infectious diseases."

Together with researchers at NCATS, part of the National Institutes of Health (NIH), they worked to develop non-infectious probes to study SARS-CoV-2, which is the causative virus of the current COVID-19 pandemic.

"Simply put, keeping the virus out of cells prevents it from replicating, propagating, and exacerbating infection," said Mason Wolak, Ph.D., acting head of NRL's Optical Nanomaterials Section. "The ultimate goals of the collaboration are to clarify the fundamental mechanisms by which SARS-CoV-2 causes infection and to screen and identify potential drugs to inhibit these mechanisms."

One thing that fascinated the scientists was the potency of the quantum dot nanoparticles to induce translocation of ACE2 from the cell membrane to the interior of the cell through a process called endocytosis. Kirill Gorshkov, Ph.D., an NCATS research scientist, said experiments to block endocytosis prevented internalization of the quantum dot pseudovirus and ACE2 receptor complex.

"While we had some idea that this was possible, the extent to which this occurred with very low amounts of quantum dot pseudo-virions suggested we had a powerful system to track viral attachment and effects on the cell in real time, since these quantum dots are fluorescent," said Gorshkov.

The nanoparticle probes developed at NRL are comprised of multiple Spike protein subunits attached to the surface of a light-emitting quantum dot core.

"We refer to these probes as 'Pseudo-virions' because they approximate the shape of the SARS-CoV-2 virus while also mimicking their physiological interactions with human cells," said Wolak. "Light emitted from the Pseudo-virions allows spatiotemporal tracking of their interaction with human cells."

Wolak went on to say that binding to ACE2 is seen as the initial step of the virus towards cellular infection. Successful inhibition of this binding is an extremely high priority in the search for therapeutic interventions to mitigate the impact of the pandemic on military and public health.

"Protecting the health of deployed warfighters is of the utmost importance to ensure mission readiness and maintain fleet readiness," said Wolak. "Navy ships represent the ultimate 'closed system' - warfighters share close quarters where social distancing is nearly impossible to realistically enforce. This results in conditions that are ripe for rapid and extensive outbreaks, such as the one reported on the USS Theodore Roosevelt, which threaten mission success."

NRL and NCATS are currently designing and testing the feasibility of high-throughput cellular imaging tests to screen entire libraries of therapeutic agents for inhibition of Spike/ACE2 binding and internalization.

"This also opened the door for high-throughput testing of new drugs uncovered by the other approaches at NCATS, to cross-validate the compounds with our system, and to test completely new therapeutic modalities developed at NCATS and elsewhere both biochemically at NRL, and in cell-based assays at NCATS," said Gorshkov.

These tests, carried out at NCATS, would allow for screening of up to 1,536 drug targets per experiment.

"Our team at NRL brings world-class expertise in the field of quantum dot/nanoparticles for biological applications," said Oh. "Merging our resources with the NCATS team's expertise resulted in research that couldn't be done by one team on its own."

Further research is planned to investigate the mechanism that increases infectiousness of SARS-CoV-2 with mutated Spike proteins. The NRL/NCATS team also plans to explore the possibility of using the pseudo-virions for site-specific intracellular drug delivery for purposes of disrupting SARS-CoV-2 replication mechanisms.

Wolak said, "It is very important to note that the Spike-containing pseudo-virion has potential for broad application of intracellular drug delivery to combat not only COVID19, but any disease that targets cells with ACE2 receptors."

Gorshkov said, he hopes the research excites and stimulates the next generation of future researchers to embark on a journey of exploration.

"I hope this story serves to engage young minds into the realm of what is possible when people work together, both scientifically and otherwise," said Gorshkov. "By forging these strong relationships, we can synergize our efforts and come to novel solutions from completely different perspectives and viewpoints."

CALVERT ISLAND, British Columbia --- Researchers have identified an invasive blood-sucking parasite on mud shrimp in the waters of British Columbia's Calvert Island. The discovery represents the northern-most record of the parasite on the West Coast and is likely an indication of its ability to spread without human transport.

Orthione griffenis, a cough drop-sized crustacean native to Asia and Russia, has decimated mud shrimp populations in California and Washington over the past 30 years, causing the collapse of delicate mudflat ecosystems anchored by the shrimp. By the 2000s, it had reached as far as Vancouver Island. The discovery of O. griffenis at Calvert Island, described in a new study, represents a northward leap of more than 180 miles.

Scientists found the parasite during a 2017 bioblitz, organized by the Hakai Institute and the Smithsonian Institution's Marine Global Earth Observatory, in which they intensely surveyed and documented marine life.

"I was on the lookout for things that seemed out of place," said study lead author Matt Whalen, a Hakai postdoctoral researcher at the University of British Columbia who studies coastal biodiversity. "But this particular parasite wasn't initially on my radar."

Most scientists believed the parasites' expansion was exclusively mediated by human transport - O. griffenisis thought to have first arrived in North America by traveling in ships' ballast water. Their appearance at Calvert Island, 150 miles from the nearest city of more than 5,000 people, shows "clearly, they can do it on their own," said study co-author Gustav Paulay, curator of invertebrate zoology at the Florida Museum of Natural History.
 

"This is such an astonishingly spectacular part of the planet," he said. "During the bioblitz, one of the things we talked about was that there were no invasive species at all. And then we found this thing."

Whalen described the find as "a bit depressing."

"We tended to associate this parasite with places that have a lot of marine traffic and aquaculture, like California and Oregon," he said in a statement. "Finding them on Calvert Island really suggests that there's very little preventing the spread because of the parasite's life cycle."

The parasite is a bizarre crustacean called a bopyrid isopod. In the pre-adult part of its life, it hitches a ride on planktonic copepods - an intermediate host that allows the isopods to travel to new and far-flung mudflats in search of shrimp blood. As adults, the parasites attach to the gills of another crustacean host, in this case a mud shrimp, Upogebia pugettensis, and proceed to sap the life from it. Infected mud shrimp are so hard done by that they lack the required energy to reproduce.

"They're essentially castrated," Paulay said.

Mud shrimp may not be much to look at - much like crayfish with stumpier claws - but these homely crustaceans play an outsized role as environmental engineers in the mudflats of the Pacific Coast. They cycle nutrients when they filter food, pumping oxygenated water into an expansive network of tunnel dwellings, which provide housing for a suite of creatures, including gobies, worms, clams and other shrimp species. The shrimp's presence affects how the entire mudflat ecosystem functions - or doesn't.

When a parasite coevolves in the same place as its host, they often reach a sort of détente, Paulay said. After all, the parasite needs a host to survive, and killing it off at once would not make a great long-term strategy. But when a parasite is introduced from elsewhere, that armistice may never arrive.

"The infection rates on Calvert Island were higher than I would've anticipated," Whalen said. "About one in four hosts were parasitized. That's a pretty good chunk of the population."

For now, scientists are tracking the northward spread of the parasite. The parasite's prevalence on Calvert Island shows that it may only be a matter of time before it reaches the North Coast of British Columbia and moves onward to Alaska, the upper edge of the mud shrimp's range.

For Paulay, the discovery of O. griffenis also underscores how marine bioblitzes can function as early warning systems for invasions.

"Every bioblitz we do, we find invasive species," he said. "If you catch them early enough, you have a chance to do something about it."

DALLAS, September 17, 2020 -- An investigation of the Finnish Twin Cohort reaffirmed a link between smoking and subarachnoid hemorrhage (SAH), a type of bleeding stroke that occurs under the membrane that covers the brain and is frequently fatal. The new study by researchers in Finland is published today in Stroke, a journal of the American Stroke Association, a division of the American Heart Association.

In a 2010 study of nearly 80,000 twins from Denmark, Finland and Sweden, results suggested that SAH had more to do with external risk factors and very little to do with genetic influence. Twins share either all or half their genes (identical vs. fraternal) so they are valuable for studies designed to evaluate the role of genetics versus environmental factors in disease development.

In this study, researchers sought to clarify the factors involved when only one twin suffered from fatal bleeding in the brain and hypothesized that smoking - the most important environmental risk factor - could play a significant role. This study utilized health care data from the Finnish Twin Cohort, a national database of 32,564 individuals (16,282 same-sex, twin pairs in Finland) who were born before 1958 and alive in 1974, and followed for over 42 years between 1976 and 2018. Researchers identified 120 fatal bleeding stroke events among the twins, and the strongest link for a fatal brain bleed was found among smokers.

"Our study provides further evidence about the link between smoking and bleeding in the brain," said corresponding researcher Ilari Rautalin, B.M., a sixth-year medical and Ph.D. student at the University of Helsinki in Finland.

Data collected from surveys included smoking; high blood pressure (diagnosis or use of antihypertensive medications); physical activity; body mass index; education; and alcohol use. Participants were separated into two groups: smokers (occasional or current) or non-smokers (never and former). Current smokers were classified according to the number of cigarettes smoked per day: light, less than 10; moderate, 10-19; heavy, 20 or more.

The analysis of the 120 fatal bleeding events found:

Four fatalities occurred among both twins in two pairs. In the remaining 116 fatalities, one twin died of bleeding in the brain, while the other died of another cause, migrated during the follow-up or was still alive at the end of the study follow-up.

Heavy and moderate smokers had 3 times the risk of fatal bleeding in the brain, while light smokers had slightly less at 2.8 times the risk.

Median age at the fatal brain bleed was 61.4 years.

Risk factors such as high blood pressure, lower physical activity rates and being female were not found to be significant influences in this investigation, unlike prior studies. Smoking was associated with fatal bleeding in the brain consistently in both men and women and with bleeding stroke deaths within twin pairs where only one of the twins died from a SAH.

The current study did not have data on non-fatal SAH events and researchers were not able to estimate the impact of former smoking on these brain bleeds. Former smokers and never smokers were combined in the non-smoking category. Researchers were also not able to confirm the aneurysmal origin of SAHs (no patient data was available) and may have included a few non-aneurysmal SAH events.

"This long-term study in twins helps to confirm the link between subarachnoid hemorrhage and smoking," said Rose Marie Robertson, M.D., FAHA, the American Heart Association's deputy chief science and medical officer and co-director of the AHA Tobacco Center for Regulatory Science, who was not involved in the study. "Not smoking or quitting if you've already started, is an essential component of primary prevention."

As more people work temporary gigs with little protection, or fear layoffs in an unstable economy, job insecurity is on the rise. These stresses understandably contribute to poor mental health and feelings of anxiety. But given gender disparities in the workforce - women are more likely to work temporary jobs and receive lower pay - researchers were curious whether job insecurity affected men and women differently.

A study published in Frontiers in Sociology analyzed data from the European Working Conditions Survey, looking at results from 2005, 2010, and 2015. The survey asked people to what extent they thought they might lose their job in the next six months and whether they had experienced anxiety over the last 12 months. The study found that, in Europe, men and women actually reacted to job insecurity fairly similarly. Female workers reported similar rates of anxiety due to an insecure job to their male counterparts. According to Dr. Egidio Riva, a co-author of the study and researcher at the University of Milano-Bicocca in Italy, this may be due to trends towards gender egalitarianism in Europe.

But while women and men might be affected at similar rates, Riva says that job insecurity is very much still a real concern. "Public health consequences of job insecurity need to be seriously considered, given that recent changes and reforms in European labour markets, as well as the current COVID-19 crisis, are likely to result in a higher prevalence of workers, both males and females, feeling threatened by involuntary job loss," he said.

In order to analyze whether the threat of job insecurity was more pronounced in certain European countries due to socioeconomic, cultural, or political variables, Riva and his co-author, Dr. Anna Bracci of the University of Applied Sciences and Arts of Southern Switzerland, used multilevel modeling analyses. They found few cross-national differences in their results, meaning the relationship between job insecurity and anxiety did not vary between countries. The study was limited by the fact that all data was self-reported and taken at a single time point, so cause-and-effect cannot be determined.

Riva says that the findings "have practical implications for both policymakers and employers" and suggests that "generous and more effective active labour market programmes are needed" in order to address perceived job insecurity and its associated mental health challenges.

To understand the massive capabilities and complexities of the brain, neuroscientists segment it into regions based on what they appear to do--like processing what we sense or how to move. What's been lacking, however, is an ability to tie those functional maps precisely and consistently to matching distinctions of physical structure, especially in live animals while they are performing the functions of interest. In a new study, MIT researchers demonstrate a new way to do that, providing an unprecedented pairing of functional mapping in live mice with distinguishing structural information for each region all the way through the cortex into deeper tissue below.

"Our study shows for the first time that structural and functional coupling of visual areas in the mouse brain can be detected at sub-cellular resolution in vivo," wrote the authors based in the lab of Mriganka Sur, Newton Professor of Neuroscience in The Picower Institute for Learning and Memory and the Department of Brain and Cognitive Sciences at MIT.

The technique could give scientists more precise ways to distinguish the borders and contents of regions they wish to study and could help them better understand the way that structural distinctions develop within individuals in different functional regions over time. Sur's lab, for instance, is intensely interested in understanding the especially complex development of vision. Humans have 35 or so distinct functional regions that contribute to processing vision, Sur notes, and even mice have 10.

"There is something profound in the way that vision is represented and created in mammalian brains," Sur said. "Where do these areas come from, what do they mean and what do they do? It has not been easy to understand how they differ. The critical thing is to precisely map or match the functional representation of each area with its anatomical uniqueness."

Combining function and structure

To develop tools to help answer those questions, postdoc Murat Yildirim led the study published in Biomedical Optics Express. In it he describes how the research team combined a method of charting functional areas--retinotopic mapping--with deep structural information measured by a technology he has helped to pioneer--third-harmonic generation (THG) three-photon microscopy.

In retinotopic mapping, researchers can identify functional regions by engineering neurons to flash when they become electrically active (and show changes in calcium) in response to a particular stimulation. For example, scientists could show a mouse a pattern moving across a screen and mark where neurons light up, with each area showing a characteristic location and pattern of response.

Three-photon microscopy can finely resolve individual cells and their smaller substructures as deep as a millimeter or more--enough to see all the way through the cortex. THG, meanwhile, adds the capability to finely resolve both blood vessels and the fibers of a material called myelin that wrap the long, tendrilous axons of many neurons. THG does not require adding any labeling dyes or chemicals.

Crucially, THG yields an important optical measure called effective attenuation length (EAL), which is a measure of how much the light is absorbed or scattered as it moves through the tissue. In the study, Yildirim and co-authors show that EAL specifically depends on each region's unique architecture of cells, blood vessels and myelin. They measured EAL in each of six visual functional regions and showed that the EAL significantly differed among neighboring visual areas, providing a structural signature of sorts for each functional area. Their measurements were so precise, in fact, that they could show how EAL varied within functional regions, being most unique toward the middle and blending closer to the values of neighboring regions out toward the borders.

In other words, by combining the retinotopic mapping with THG three-photon microscopy, Yildirim said, scientists can identify distinct regions by both their function and structure while continuing to work with animals in live experiments. This can produce more accurate and faster results than making observations during behavior and then dissecting tissue in hopes of relocating those same exact positions in preserved brain sections later.

"We would like to combine the strength of retinotopic mapping with three-photon imaging to get more structural information," Yildirim said. "Otherwise there may be some discrepancies when you do the live imaging of brain activity but then take the tissue out, stain it and try to find the same region."

Especially as three-photon microscopy gains wider adoption and imaging speeds improve--right now imaging a millimeter deep column of cortex takes about 15 minutes, the authors acknowledge--the team expects its new method could be used not only for studies of the visual system but also in regions all around the cortex. Moreover it may help characterize disease states as well as healthy brain structure and function.

"This advance should enable similar studies of structural and functional coupling in other sensory and non-sensory cortical areas in the brains of mice and other animal models," they wrote. "We believe that the structural and functional correlation in visual areas that we describe for the first time points to crucial developmental mechanisms that set up these areas, thus our work would lead to a better fundamental understanding of brain development, and of disorders such as Alzheimer's, stroke and aging."

The calcification of the carotid artery is a sign of advanced arteriosclerosis, which may be associated with chronic coronary artery disease (CAD) and can lead to death. Such calcification can be seen in regular oral panoramic radiography.

Prior research has already shown that carotid artery calcification is detectable by panoramic radiography. Now, for the first time, researchers included coronary angiography in a study where patients were followed-up for 10 years. Furthermore, the patients' oral microbiota was examined and the quantity of antibodies to bacteria associated with oral infections was measured.

A total of 508 middle-aged patients who had been referred to coronary angiography due to cardiac symptoms in 2008-2018 were enrolled in the study.

The study was carried out collaboratively by the University of Helsinki, the University of Oulu, the University of Eastern Finland and Karolinska Institutet.

The findings have been published in the International Endodontic Journal.

"Carotid artery calcification was statistically directly linked with several stenosed arteries found in coronary angiography, as well as with chronic coronary artery disease," says Docent Pirkko Pussinen from the University of Helsinki.

Calcification detected in one-fifth of study subjects

In the study, carotid artery calcification was found in 102 patients (20.7%), with 81 (16.4%) of the cases determined as moderate and 21 (4.3%) as severe. Calcification was considered severe when the deposit was more than 10 millimetres in diameter. In statistical analyses, the patients' age, gender, smoking habits, diabetes, disturbances of lipid metabolism (or dyslipidemia) and blood pressure were taken into consideration.

"The findings indicate that calcification was directly associated with not only chronic CAD, but also with apical periodontitis, root canal therapies, alveolar bone loss, the severity of periodontal inflammation, a high level of gram-negative bacteria in dental plaque and antibodies in the saliva that bind with these bacteria. At the same time, the link between calcification and acute myocardial infarction was not statistically significant," Pussinen describes the results.

During the decade-long follow-up period, a total of 105 patients died (20.7%), with 53 deaths (10.4%) caused by cardiovascular diseases. Carotid artery calcification was diagnosed in 17.5% of the patients who were alive at the end of the follow-up period. Among the deceased patients, the prevalence of calcification was high: in patients who died of cardiovascular diseases, the percentage was 35.8%, while in patients who died of other causes it was 29.2%.

In the cases with severe carotid artery calcification detected in dental radiography, the risk of death caused by cardiovascular diseases was more than threefold.

"Oral infections are fairly common, but they are often latent and found only through radiography. Radiographs of the whole jaw conducted in conjunction with dental care can reveal a cardiovascular disease risk as an incidental finding. If carotid artery calcification is seen in the radiograph, the patient must be referred to further examinations and an assessment of the need for treatment," Docent Pussinen sums up.

SAN ANTONIO -- Sept. 16, 2020 -- A Southwest Research Institute scientist has identified stellar phosphorus as a probable marker in narrowing the search for life in the cosmos. She has developed techniques to identify stars likely to host exoplanets, based on the composition of stars known to have planets, and proposes that upcoming studies target stellar phosphorus to find systems with the greatest probability for hosting life as we know it.

"When searching for exoplanets and trying to see whether they are habitable, it's important that a planet be alive with active cycles, volcanoes and plate tectonics," said SwRI's Dr. Natalie Hinkel, a planetary astrophysicist and lead author of a new paper about this research in the Astrophysical Research Letters. "My coauthor, Dr. Hilairy Hartnett, is an oceanographer and pointed out that phosphorus is vital for all life on Earth. It is essential for the creation of DNA, cell membranes, bones and teeth in people and animals, and even the sea's microbiome of plankton."

Determining the elemental ratios for exoplanetary ecosystems is not yet possible, but it's generally assumed that planets have compositions similar to those of their host stars. Scientists can measure the abundance of elements in a star spectroscopically, studying how light interacts with the elements in a star's upper layers. Using these data, scientists can infer what a star's orbiting planets are made of, using stellar composition as a proxy for its planets.

On Earth, the key elements for biology are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfer (or CHNOPS). In today's oceans, phosphorus is considered the ultimate limiting nutrient for life as it's the least available chemical necessary for biochemical reactions.

Hinkel used the Hypatia Catalog, a publicly available stellar database she developed, to assess and compare the carbon, nitrogen, silicon, and phosphorus abundance ratios of nearby stars with those in average marine plankton, the Earth's crust, as well as bulk silicate on Earth and Mars.

"But there's so little phosphorus stellar abundance data," Hinkel said. "Phosphorus data exists for only about 1% of stars. That makes it really difficult to figure out any clear trends in between the stars, let alone the role of phosphorus in the evolution of an exoplanet."

It's not that the stars are necessarily lacking phosphorus, but it's difficult to measure the element because it's detected in a region of the light spectrum not typically observed: at the edge of the optical (or visual) wavelengths of light and infrared light. Most spectroscopic studies are not tuned to find elements in that narrow range.

"Our Sun has relatively high phosphorus and Earth biology requires a small, but noticeable, amount of phosphorus," Hinkel continued. "So, on rocky planets that form around host stars with less phosphorus, it's likely that phosphorus will be unavailable for potential life on that planet's surface. Therefore, we urge the stellar abundance community to make phosphorus observations a priority in future studies and telescope designs."

Moving forward, these findings could revolutionize target star selections for future research and clinch the role elements play in exoplanet detection, formation and habitability.

The flooding season had just ended in China. Persistent strong precipitation events in many regions of China resulted in severe flooding disasters in the just passed summer of 2020. It is of great significance to capture precursor signals of persistent strong precipitation events.

To find the signal, Prof. XIAO Ziniu and his team from The State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences, and their collaborators used a powerful analysis tool - the intraseasonal oscillation (ISO) of isentropic potential vorticity (PV) - to track precursors near the tropopause preceding persistent strong precipitation in South China.

The results were published on Sept. 2 in Climate Dynamics.

The researchers found that the early signals leading to persistent heavy rainfall in South China originate from two regions: the Arctic region and the tropical monsoon region.

"20 days before the peak rainfall, the western Tibetan Plateau and the northern side of the East Asian westerly jet near the tropopause are two transit points for the anomalous potential vorticity to strengthen and change propagating direction," said ZHAO Liang, the first author of the study. ZHAO is a senior engineer with LASG.

It is very critical for prediction to find the special early configuration of synoptic systems for the occurrence of persistent heavy rainfall events.

"We find that when the anomaly low pressure is surrounded by three anomaly high pressure systems, including South Asia high, Okhotsk Sea blocking high and the western Pacific subtropical high, this special situation is often responsible for the following persistent heavy rainfall in South China," said Prof. XIAO.

According to this study, 10 days before the peak rainfall, the joint action of the South Asia high and the Okhotsk Sea blocking high compresses the anomaly cold air between the two highs, and forms a narrow and steady cold air transport channel on the inclined isentropic surface. It enables the cold air to a lower latitude and continually meet with the warm and moist air in South China brought by the anomaly strong subtropical high, forming a persistent heavy precipitation.

"Our finding provides a new potential factor for the prediction of regional persistent heavy rainfall," said Prof. XIAO.

Building materials with a clear composition and stable structure is one of the primary challenges in chemistry and cluster science. Ongoing extensive efforts have been paid to exploring new stable clusters thus to construct new materials and to understand structural evolution bridging atoms and macroscopic matter. This is interesting yet challenging in chemistry. In the past decades, researchers have achieved significant advances, such as the discovery of fullerene C60, tetrahedral Au20, and all-boron fullerene B40, etc. In particular, a few "magic " metal clusters have unique stability, such as Al13?, surviving the reaction with oxygen. Such metal clusters often possess closed-shell electronic structure and geometric structure, which embodies the near free electron gas (NFEG) theory of metal and epitomizes the jellium model of clusters. In other cases, cluster stability could be related to aromaticity or superatom characteristics, pertaining to a large HOMO-LUMO gap, electron detachment energy and spin excitation energy. Besides, it was found that the doping of ligands, such as hydrogen or halogen, could bring forth changes to the stability of metal clusters, enabling to passivate or activate the metal clusters. This principle has been greatly embodied in understanding the stability of ligand-protected metal clusters.

In a new overview published in the Beijing-based National Science Review, scientists in Institute of Chemistry Chinese Academy of Sciences, and Peking University Shenzhen Graduate School, etc. present an interesting finding of a very stable neutral Co13O8 cluster which possess unique cubic structure akin to perovskite and exhibit cubic aromaticity. This new class of neutral oxygen passivated metal cluster is expected to be used as genetic material, and the researchers named it "metalloxocubes".

Using the home-made deep ultraviolet laser ionization mass spectrometry (DUV-LIMS) with high ionization efficiency of neutral cobalt clusters, they observed the reactions of Con (n=2-30) with oxygen. Interestingly, a particularly stable species, Co13O8, shows dominant mass abundance in the presence of a large flow rate of oxygen gas (as shown in the Figure below).

In order to study its geometric structure, authors used three independent methods to search and identify the global minimum structure of the Co13O8 clusters, and obtained a consistent result unveiling its unique stability related to the cubic structure and a large HOMO-LUMO gap (2.14 eV). Ab-initio molecular dynamics (AIMD) simulations indicate that Co13O8 has outstanding thermal stability. The thermodynamics and reaction kinetics demonstrated the structural evolution from icosahedral Co13 to cubic Co13O8 clusters.

Further, the authors found a large value of negative nuclear independent chemical shift (NICS), with NICS(0) = -54.0 ppm at the Co4O4 plane center of the cubic Co13O8 and NICS(1) = -22.0 ppm with 1.0 Å above the plane surface, indicating remarkable aromaticity of this cluster. The integrate net current of 5.14 nA/T with an external magnetic field perpendicular to the Co4O4 plane. The electronic structure and orbital analyses revealed that Co13O8 has cubic aromaticity in accordance with the '6n+2' rule of electron counting.

It is interesting and challenging in chemistry to understand the structure evolution from atoms to macroscopic matter and construct new materials with well-defined components and regular polyhedron structures. Considering the unique stability and cubic aromaticity of Co13O8, this class of neutral oxygen- passivation metal clusters is named as "metalloxocubes", expecting to become a suitable candidate for gene materials.

Philadelphia, September 16, 2020 - The risk of developing major depressive disorder (MDD) surges during adolescence-particularly for girls. Cognitive behavioral therapy (CBT) can be an effective treatment, but only about half of girls diagnosed with depression show significant improvement. Researchers at Harvard Medical School and McLean Hospital have now identified a non-invasive test of brain function that could help predict who will respond to CBT.

The article, appears in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, published by Elsevier.

"The study is very significant because it suggests that readily acquired EEG measures related to processing of rewards and losses can serve as biomarkers for predicting treatment response and tracking the effects of therapy in the brain," said Cameron Carter, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. "Future work using these measures may help clinicians determine the best treatment - for example, CBT versus medications - for a given young person suffering with depressive symptoms."

The study included 36 teenage girls with MDD and 33 healthy control adolescents. Girls with MDD were offered a 12-week course of CBT. Overall, the girls who underwent treatment saw a significant improvement in their symptoms from the "severe" to "mild" range.

At the start of the study, all participants were assessed for mental health and were given a task, much like a video game, in which they could win or lose money. The researchers used electroencephalography (EEG), which measures brain activity from outside the skull, to test participants' brain responses during the task. The girls repeated the task (and the EEG test) at the midpoint of treatment, and again after completion of treatment. Control participants, who did not receive CBT, also performed the task and EEG measurements at three corresponding times.

The researchers measured brain signals called event-related potentials (ERP), which are signature responses seen during such tasks. One type of ERP reflects the brain's immediate response to monetary rewards vs. losses; this measure did not predict who would respond to CBT. Another, longer-lasting type of ERP reflects the brain's more sustained emotional processing of rewards vs. losses.

"We found that the brain measure of sustained - but not initial - responsiveness to rewards predicted greater symptom improvement, which may help to inform which depressed adolescents are most likely to benefit from CBT," said Christian Webb, PhD, lead author of the study.

The girls with a larger ERP response showed greater improvement in symptoms.

Although the precise mechanisms that account for symptom improvement in CBT for depressed teens is not yet clear, this study also revealed that EEG responses to monetary loss changed over time with treatment. That finding, Dr. Webb said, may reflect that, "in addition to reducing depressive symptoms, successful CBT may attenuate underlying neural hypersensitivity to negative outcomes among depressed adolescent girls," ultimately leading to symptom improvement.

The concentration of mercury in the fish in Alaska's Yukon River may exceed the EPA's human health criterion by 2050 if greenhouse gas emissions that cause global warming are not constrained, according to scientific research funded in part by NASA. This first of its kind research estimates potential releases of mercury from thawing permafrost under high and low carbon emissions scenarios. The researchers predict that by 2200, the mercury emitted into both the atmosphere and water annually by thawing permafrost will compare with current global anthropogenic mercury emissions. That's because higher carbon emissions lead to faster and more
atmosphere and water, where it can accumulate in wildlife like fish. The team's results were published Sept. 16 in Nature Communications.

"If we can hit the Paris Accord target, we expect minimal impacts to mercury concentrations in fish and water. If we continue with unconstrained greenhouse gas emissions, however, it is likely that we will see large increases in mercury concentrations," said Kevin Schaefer, a scientist at the National Snow and Ice Data Center (NSIDC) and lead researcher on the project. Mercury emissions of these magnitudes could have a global impact. "What happens in the Arctic does not stay in the Arctic," said Schaefer, "The mercury emissions from thawing permafrost could persist for centuries, impacting the environment both locally and globally."

In 2018, Schaefer and several of his colleagues found that permafrost soils store nearly twice as much mercury as all other soils, the ocean and the atmosphere combined. That work was funded by NASA as part of the Arctic-Boreal Vulnerability Experiment (ABoVE), a major effort to improve understanding of how climate change is affecting Arctic ecosystems, and how those changes ultimately affect people and places in the Arctic and beyond. Now, the researchers have created a model - which relies in part on data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Terra satellite - to predict how mercury emissions from thawing Arctic permafrost will change under different global emissions scenarios.

The new paper characterizes the release of mercury from thawing permafrost for high and low carbon emissions scenarios based on two of the four Representative Concentration Pathways (RCPs) from the Intergovernmental Panel on Climate Change's Fifth Assessment Report (AR5). The high carbon emissions scenario (RCP 8.5) assumes unconstrained "business as usual" emissions, while the low carbon emissions scenario (RCP 4.5) assumes carbon emissions consistent with the Paris Agreement global target of less than 2 degrees Celsius of warming above pre-industrial levels.

The results indicate minimal impacts to mercury concentrations in water and fish for the low carbon emissions scenario and large increases for the high carbon emissions scenario. At the global level, the high carbon emissions scenario would significantly increase the amount of mercury released into the atmosphere, where it would persist in the environment for centuries. At a local level, this would result in large increases to mercury concentrations in fish and water in the Yukon River. For the high emissions scenario, mercury concentrations could double in the Yukon River by 2100. The low carbon emissions scenario shows minimal mercury releases to the atmosphere and small changes to mercury concentrations in fish and water. For the low emissions scenario, mercury concentrations would likely increase by only about 14 percent and would not exceed EPA criterion by 2300.

"The thaw of permafrost due to climate change may release mercury as well as greenhouse gases like methane. We need to comply with the Paris Accord target of 2 degrees C. Otherwise, under a high emission scenario, a significant portion of mercury will be released to the environment, and it will continue for hundreds of years," said Yasin Elshorbany, a co-author on the study from the University of South Florida St. Petersburg campus.

The Yukon River is the fifth largest drainage basin in North America and home to one of the world's longest salmon runs. It serves as an important commercial and subsistence fishery.

In everyday life, measuring temperature is pretty straightforward. But in the quantum world, which deals with the super small and the ultra-cold, determining how hot or cold something is starts to get more challenging. Now, in a collaboration between the Okinawa Institute of Science and Technology Graduate University (OIST), University College Dublin and Trinity College Dublin, researchers have described a quantum process that uses a single atom as a thermometer to sensitively measure the temperature of an ultra-cold gas.

"As quantum physicists, our ultimate goal is to create and measure systems as close as possible to absolute zero. This is the lowest temperature limit, around -273°C or zero on the Kelvin temperature scale, and it's when particles stop moving. These ultra-cold systems are important for successfully harnessing quantum technologies or reducing noise in quantum experiments," said Professor Thomas Busch, head of the Quantum Systems Unit at OIST and co-author of the study, published as an Editor's Suggestion in Physical Review Letters. "So being able to detect minute changes in temperature, at only tens of billionths of a degree above zero kelvin, is critical."

Typically at room temperature there are more than a hundred billion trillion atoms whizzing about at speeds of up to 300 - 400 meters per second. "When we measure the temperature in a room, we don't try and measure the movement of all these atoms, we just take measurements from a thermometer," said Dr. Thomás Fogarty, a scientist in the Quantum Systems Unit. "Although one could, in principle, try to measure the velocity of all the atoms in a quantum system, we wanted to design a simpler and better method that uses a quantum thermometer."

But using a thermometer to measure a quantum system isn't simple. These systems are colder than any place that exists naturally in the universe. They are also very small, containing only about 100,000 atoms in the gas. If the thermometer is too large or too warm it would heat up the gas being measured and destroy the system's quantum properties. So instead, the approach this collaboration took was to use a thermometer that was also very small and very cold - a single, super-cooled atom.

When first added into the system, this thermometer atom exists in two different energy states at the same time - a unique, counter-intuitive property of quantum systems. But as the thermometer atom interacts with the ultra-cold gas, the quantum features of this combined energy state decay. The rate at which this decay occurs is directly related to the temperature of the ultra-cold gas being probed, so as the scientists measure the state of the thermometer atom, they can accurately infer the temperature.

"This process essentially destroys the 'quantumness' of the thermometer atom through interactions with the gas, making it truly a quantum thermometer", Dr. Fogarty explained.

The researchers also reported the optimal timings for when the measurements should be taken, as well as the ideal strength of the interactions between the single atom and the gas, to get the best sensitivity and the least amount of noise. The colder the gas, the slower the decay process occurs, as the single atom interacts more slowly and less often with the gas. "Therefore, in order to measure temperature at the lowest extremes we need to wait a long time before measuring and we require weaker interactions to maximize the signal and minimize the noise," added Dr. Fogarty.

The team is now exploring numerous paths to improve the method's sensitivity, such as by using machine learning to optimize the interactions between the thermometer atom and the gas, or by introducing more thermometer atoms into the system so more complex quantum interactions can occur.

"This new method has pushed the bounds of thermometry, which has important applications for quantum technology," concluded Prof. Busch. "I expect that we are going to see it being used very soon in experiments."

A U of A biologist is part of an international team of researchers building a volunteer network of citizen scientists to help monitor the abundance of dragonflies and damselflies.

Recent studies have indicated that insect species in general are declining throughout the world and could be headed toward collapse due to intensive agricultural practices, climate change and habitat loss. For many species, however, there isn't enough baseline data to determine trends in insect abundance.

Adam Siepielski, associate professor of biology, is part of a team working on a solution -- establishing a volunteer network that will collect data on odonata, the scientific name for dragonflies and damselflies. Odonata are easy to spot, often vividly colored and an important indicator group of species reflecting environmental changes in freshwater biodiversity.

"Volunteer nature enthusiasts can greatly help to monitor the abundance of dragonflies and damselflies, iconic freshwater sentinels and one of the few nonpollinator insect groups appreciated by the public and amenable to citizen science," the scientists wrote in a paper published in the journal BioScience.

Researchers propose modeling the volunteer network on a similar collection of projects, organizations and individuals dedicated to butterflies. "The network has improved knowledge of not only butterfly geographical distributions but also their relative population sizes across years and the effects of large-scale environmental change," researchers wrote.

"We are hopeful that with similar efforts dedicated to odonata, great strides can be made in our understanding of changes in their abundances and distributions too. They really are amazing animals and fascinating to observe," said Siepielski.

An odonata network would fill in gaps from areas of the world with little information, and incorporate existing data-collection efforts. Ideally, volunteers would collect data at a fixed location for 10 to 15 years, and have a standardized portal to report their findings.

"An army of amateur naturalists may contribute far more data than a small cadre of professional observers," the researchers wrote. "Citizen science promotes biophilia while contributing enormously to understanding large-scale biodiversity loss and environmental change, especially in developing or transitioning regions."

The concentration of mercury in fish in Alaska’s Yukon River may exceed EPA mercury criterion by 2050 if greenhouse gas emissions that cause global warming are not constrained, according to new scientific research led by the National Snow and Ice Data Center’s (NSIDC) Kevin Schaefer. This first of its kind research estimates potential releases of mercury from thawing permafrost in high and low emissions scenarios. The researchers predicts that by 2200, the mercury emitted into the atmosphere annually by thawing permafrost could compare with current global anthropogenic emissions under a high emissions scenario. Their results were published on September 16 in Nature Communications.

“If we can hit the Paris Accord target, we expect minimal impacts to mercury concentrations in fish and water. If we continue with unconstrained emissions, however, it is likely that we will see large increases in mercury concentrations,” said Schaefer. Emissions of these magnitudes could have a global impact. “What happens in the Arctic does not stay in the Arctic. The mercury emissions from thawing permafrost could persist for centuries, impacting the environment both locally and globally.”

Back in 2018, Schaefer and several of his colleagues found that permafrost soils store nearly twice as much mercury as all other soils, the ocean and the atmosphere combined. That work was funded by NASA as part of the Arctic-Boreal Vulnerability Experiment (ABoVE), a major effort to improve understanding of how climate change is affecting the Arctic ecosystems, and how those changes ultimately affect people and places in the Arctic and beyond. Now, the researchers have created a model—which relies in part on data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA’s Terra satellite—to predict how mercury emissions from thawing Arctic permafrost will change under different global emissions scenarios.

The paper characterizes the release of mercury from thawing permafrost for high and low emissions scenarios based on two of the four Representative Concentration Pathways (RCPs) from the Intergovernmental Panel on Climate Change’s Fifth Assessment Report. The high emissions scenario (RCP 8.5) assumes unconstrained, ‘business as usual’ emissions, while the low emissions scenario (RCP 4.5) assumes emissions consistent with the Paris Agreement global target of two degrees Celsius of warming above pre-industrial levels.

The results indicate minimal impacts to mercury concentrations in water and fish for the low emissions scenario and large increases for the high emissions scenario. The high emissions scenario shows mercury releases to the atmosphere comparable to current anthropogenic emissions, with large increases to mercury concentrations in fish and water in the Yukon River. The low emissions scenario shows minimal releases to the atmosphere and small changes to mercury concentrations in fish and water. For the high emissions scenario, mercury concentrations could double in the Yukon River by 2100. For the low emissions scenario, mercury concentrations would likely increase by only about 14 percent and would not exceed EPA criterion by 2300.

“The thaw of permafrost due to climate change may release mercury as well as greenhouse gases like methane,” said Yasin Elshorbany of the University of South Florida St. Petersburg campus, a co-author on the study. “We need to comply with the Paris Accord target of two degrees Celsius. Otherwise, under a high emissions scenario, a significant portion of mercury will be released to the environment and it will continue for hundreds of years.”

The Yukon River is the fifth largest drainage basin in North America and home to one of the world’s longest salmon runs. It serves as an important commercial and subsistence fishery.

Along three scenic drives through Colorado's Rocky Mountains in fall, tourists will see less of a brilliant golden tree in the next 100 years, researchers from North Carolina State University projected in a new study.

Using computer modeling, researchers simulated how the distribution of quaking aspen, or Populus tremuloides, a native tree known for its brilliant yellow and orange foliage in fall and the sound of its trembling leaves, will change amid rising temperatures over the next 100 years.

They predicted quaking aspens will decline in visibility in 2120 under climate warming scenarios. Visibility will also decline along three scenic national byways in the Colorado Rockies - even if climate conditions remain at historical levels. They saw the greatest declines in the visible landscape areas.

"Aspen are sensitive to drought and warming temperatures, and empirically we are already starting to see declines," said the study's senior author Jelena Vukomanovic, assistant professor in the NC State Department of Parks, Recreation and Tourism Management. "Even if we keep current conditions, we will see declines in aspen. But under worsening climate change, the decline in aspen will be worse."

In the study, researchers modeled the distribution of quaking aspen trees visible under three scenarios: If climate does not change from historical conditions observed from 1980 to 2010; under a 4-degree temperature increase with 15 percent less precipitation; and with a 4-degree decline and 15 percent more precipitation.

For each scenario, their simulation modeled whether aspens were visible from 32,949 different vantage points along three scenic roadways in Colorado: Cache la Poudre, Trail Ridge Road and Peak-to-Peak Highway. They used a computer model of forest dynamics called the Landscape Disturbance and Succession (LANDIS-II) model to forecast where aspen will grow and used U.S. Geological Survey elevation data to model visibility along scenic roads.

In addition to factoring in changes in temperature and precipitation, they also modeled how wildfires, insects and wind events would impact aspen tree growth and distribution. These trees are intolerant of drought and shade, researchers said, but they are often the first to colonize a burned area.

Overall, they found that aspen are expected to decline in all three climate scenarios. In the two warmer scenarios, the losses were more than two times greater overall, and aspen loss was even greater in the visible areas from the scenic byways.

"We can say with good confidence that these main arteries of movement through the mountains will see a noticeable decline in visible aspen, and the loss of visible aspen is greater than the overall loss," said Vukomanovic. "It's hard to predict what people will do - build new roads, new outlooks, or create new opportunities to view the remaining stands - but there could be a negative impact to some of the communities along these routes that rely on tourism dollars from aspen viewing."

They saw that the changes in aspen varied depending on the elevation. Aspen at the lowest elevations, where they are the least abundant, saw increases under all three scenarios, but the increases were smaller with climate change. Researchers hypothesized that at these elevations, the model was capturing aspen regeneration after wildfire, but they regenerate to a lesser degree under the more extreme climate change scenarios.

"We think they are increasing at lower elevations because they're colonizing recently burned places," Vukomanovic said. "Because there's been such active fire suppression at the lower elevations where people live, when fire comes, it creates opportunities for the aspen to colonize new places. But these gains are tiny compared to losses at higher elevations."

At the middle elevations of 2,000 to 3,000 meters, where aspen are most abundant, they saw consistent decreases across all three scenarios. At the highest elevations above 3,000 meters, they saw lower declines under the climate warming scenarios. They believe this means aspen distributions will shift to higher elevations as the climate warms.

"As drought and higher temperatures at lower elevations start to increase the vulnerability of aspens to pathogens like bugs, fungi and bacteria, their suitable climate will shift upwards," said Nikki C. Inglis, a research assistant and graduate student in the Center for Geospatial Analytics at NC State and first author of the study.

Researchers said their study is important because it is evidence for how climate change will be visible to people. In addition, the aspen trees in particular are an important feature of the Colorado landscape.

"They are part of how people who live in Colorado identify themselves, and what makes this a unique landscape," Inglis said. "They draw people in from all over because the aspen trees create a sensory experience with sound and sight. And of course the color change is absolutely striking - there's nothing like it."