Culture

To manage Canada's emergency stockpile of medical supplies and personal protective equipement (PPE), the government could consider several approaches, including a "prime-vendor" model selling directly to health care organizations to minimize financial and equipment waste, according to an article in CMAJ (Canadian Medical Association Journal)

"Stock expiration is an important challenge with national stockpiles. Accordingly, a new long-term PPE supply-chain solution is urgently needed,"write Dr. Scott Laing, Department of Family Medicine, University of Ottawa, with Ellen Westervelt, Queensway Carleton Hospital, Ottawa, Ontario.

The National Emergency Stockpile System (NESS), established in 1952 as a result of the Cold War, had an estimated $300 million in assets in 2010, with an operating budget of $4 million and $7.7 million in warehouse leases. Many supplies have expired, leaving inadequate supplies during the current pandemic, and the NESS lacks an electronic inventory management system, which hampers its effectiveness.

"The Government of Canada is currently struggling to coordinate timely procurement of new PPE owing to long wait times for order fulfillment, which was also identified in the 2010 audit," write the authors. "The resulting PPE shortages have hindered provision of some health services, particularly in the community, where many family doctors have had limited access to essential PPE."

The United States and Australia face similar challenges with high costs due to equipment expiration and disposal expenses.

A long-term strategy for stockpiling critical supplies could include integrating the NESS with the commercial supply as a "prime vendor," perhaps modelled after shared services organizations.

The authors note that there are logistical challenges with a prime-vendor approach and, if pursued, the prime vendor should start on a small scale and expand only when ready.

Lecce, 25th June 2020 - Gold nanoparticles have been developed in the laboratory in order to reduce the cell death of neurons exposed to overexcitement. The study, is the result of an international collaboration coordinated by Roberto Fiammengo, researcher at the Center of Biomolecular Nanotechnologies of the IIT-Istituto Italiano di Tecnologia (Italian Institute of Technology) in Lecce (Italy). The international team also involves colleagues at the University of Genoa, Imperial College London, King's College London, the Center for Synaptic Neuroscience and Technology of the Istituto Italiano di Tecnologia in Genoa and the Max Planck Institute for Medical Research in Heidelberg.

Excessive stimulation of neurons by the neurotransmitter glutamate, which is usually involved in the excitatory communication among neurons, can damage nerve cells and cause their degeneration. This phenomenon, known with the term excitotoxicity, is common in many neuroinflammatory and neurodegenerative diseases, such as Alzheimer's and Huntington's disease, but also in case of epilepsy, brain trauma and stroke.

In particular, these nanoparticles were designed and prepared by the IIT team in Lecce (Italy), and are functionalized with peptides that allow selective inhibition of extrasynaptic glutamate receptors involved in the excitotoxicity. In fact, the size of the nanoparticles is 20 - 50 times larger than that of classic drugs resulting in the blockade of only the receptors located outside the synapses. In this way, correct neurotransmission is preserved while the excessive activation that leads to cell death is avoided.

The molecular mechanism underlying the neuroprotective effect of the nanoparticles has been clarified by the experimental work carried out by Pierluigi Valente at the University of Genoa, in collaboration with Fabio Benfenati's group of the Center for Synaptic Neuroscience and Technology of the IIT in Genoa (Italy).

The results of this research sets the basis for treatment of neurological diseases in which the excessive release of glutamate is at the basis of the pathology. The possibility of specifically blocking extrasynaptic receptors, mainly responsible for cell death, without interfering with synaptic transmission, opens up promising perspectives for targeted therapy without major side effects.

"We have developed nanoparticles with unique and necessary properties to answer to the indications of neurobiologists and physiologists - declares Roberto Fiammengo - Coordinating such a multidisciplinary group of researchers was an extremely stimulating task and the results obtained show that this is the winning approach."

"Even if, at the moment, the nanoparticles developed cannot be used in therapy, - concludes Pierluigi Valente of the University of Genoa, first author of the paper - this study shows how nanotechnology can provide important indications for treatment of many neuroinflammatory and neurodegenerative diseases."

The Ik, a small ethnic group in Uganda, are not incredibly selfish and mean as portrayed in a 1972 book by a prominent anthropologist, according to a Rutgers-led study.

Instead, the Ik are quite cooperative and generous with one another, and their culture features many traits that encourage generosity, according to the study in the journal Evolutionary Human Sciences.

"The Mountain People," an ethnography by anthropologist Colin M. Turnbull, made a big splash for an academic work. The New York Times and Time magazine reviewed the book, which inspired a stage play, and physician Lewis Thomas included an essay about the Ik in his bestselling book "The Lives of a Cell: Notes of a Biology Watcher."

The Ik live in the far northeast corner of Uganda, near its borders with Kenya and South Sudan. A Rutgers-led team of scientists studied them as part of The Human Generosity Project, a transdisciplinary effort to better understand generosity and other forms of cooperation among people around the world.

The scientists included the Ik in their project because of Turnbull's claim that, far from being generous, the Ik were extraordinarily selfish and mean. He attributed the selfish behaviors he witnessed to a culture of selfishness.

Lead author Cathryn Townsend, a former Rutgers post-doctoral scientist and faculty member now at Baylor University, spent 2016 with the Ik and returned briefly in 2017 and 2018.
She discovered that their culture includes many traits that encourage generosity. For example, a favorite Ik saying is tomora marang, which means "it's good to share," and many Ik believe that Earth spirits called kijawika monitor people's behavior, punish those who fail to share and reward the very generous.

Townsend also documented Ik generosity quantitatively using an experimental game, finding they're no less generous, on average, than any of the hundreds of other groups of people in the world who have played the same game.

Why, then, did Turnbull observe so much selfishness among the Ik? Although Turnbull was aware that they experienced a severe famine while he was there, he failed to appreciate the impact starvation has on human behavior. Instead, he followed a common tendency among cultural anthropologists to attribute all human behavior to culture.

"One implication of Townsend's work is that we must always consider the possibility that factors other than culture, including but not limited to starvation, can also shape human behavior," said senior author Lee Cronk, a professor in the Department of Anthropology in the School of Arts and Sciences at Rutgers University-New Brunswick. "Another implication is that we can no longer use the Ik as an example of a society that has embraced selfishness. Far from being an exception, the Ik are just as cooperative and generous as other people around the world. They do not deserve the reputation they have been given by Turnbull's book."

Townsend plans to return to the Ik to continue her studies of how they cooperate. She will be looking in particular at how they are interdependent with one another.

In recent years, the number of women who entered U.S. medical school surpassed the number of men. But gender inequities still exist in many areas of medicine. Of academic hospital medicine programs, 79% are run by men, Johns Hopkins researchers report in a new paper published March 3 in the Journal of General Internal Medicine, and male hospitalist leaders are more likely to have attained the rank of full professor than women leaders.

"Despite making a number of strides in medicine when it comes to gender bias, this is an area where we still haven't reached full equality," says Carrie Herzke, M.D., assistant professor of medicine and associate vice chair for clinical affairs in the Department of Medicine at the Johns Hopkins University School of Medicine.

Previous studies found that, in academic medicine, women comprise only 39% of full-time faculty and 22% of full-time professors. They are also significantly underrepresented in hospital leadership positions, and there are gender disparities regarding career advancement and compensation.

Hospital medicine as a dedicated medical specialty is a relatively young field. "Hospitalists" who are trained in internal medicine and focus their work on hospitalized patients rather than outpatient settings have only existed for about two decades. Due to how new the field is, some speculate it may have fewer gender imbalances than more established fields of medicine.

In collaboration with the Society of Hospital Medicine, Herzke and her colleagues conducted a survey of all U.S. academic hospital programs associated with the Association of American Medical Colleges. After identifying 135 programs, surveys were sent electronically to academic hospitalist leaders of each program. Participants were asked about the gender of the hospitalist program leader, the program's size and organization, faculty characteristics, and perceptions about promotion and faculty development.

"We had a sense that there were some gender issues when people had looked at these areas before," says Herzke. "Obviously, our hope was that we would see fewer inequities in our data."

Of the 135 programs, 80 responded to the survey, and responding programs did not differ significantly from nonresponding programs in terms of funding, region, age or type of institution. While programs reported approximately equal numbers of male and female faculty members, 79% of program directors were male. Moreover, 37% of male hospitalist leaders were full professors while no female hospitalist leaders held that rank.

"Even in this new specialty, we don't have gender parity," says Herzke. "There have been numerous studies suggesting that programs, and society in general, do better when we have more diverse teams and diverse leadership."

The ability to sequence the genome of a tumor has revolutionized cancer treatment over the last 15 years by identifying drivers of cancer at the molecular level. But understanding the genetic diversity of individual cells within a tumor and how that might impact the disease progression has remained a challenge, due to the current limitations of genomic sequencing.

Using a microfluidic droplet based single cell sequencing method, USC researchers have simultaneously sequenced the genomes of close to 1,500 single cells, revealing genetic diversity previously hidden in a well-studied melanoma cell line.

The study, just published in Nature Communications Biology, demonstrates the ability of single-cell sequencing to reveal possible evolutionary trajectories of cancer cells.

"We used this approach to examine a standard cancer cell-line, examined thousands of times by many different labs," said David Craig, PhD, co- director of the Institute of Translational Genomics at Keck School of Medicine of USC and study author. "What was really surprising here, was with this technology we uncovered complexity we did not expect. This line actually consistently became a mixture of different types of cells. Reexamining decades of prior work on this line - now with this new information - we have new insights into tumor evolution."

Getting a high-resolution view of cancer's complexity

Currently, the genetic information of a tumor is typically obtained by sequencing millions of tumor cells together, rather than individually. While this method offers a broad view of the genetic makeup of the tissue it can miss small populations of cancer cells within a tumor that are different from the majority of cells.

With other approaches that analyze the DNA of individual cells, the process is laborious, taking weeks to process just a few cells and requiring resources that most laboratories do not have.

For this study, researchers used an emerging technique called "single-cell copy number profiling." developed by 10X Genomics with novel analysis methods that integrated these results with those of historical methods.

"Instead of analyzing tissue DNA that is the average of thousands of cells, we analyzed the individual DNA of close to 1500 cells within a single experiment," said Dr. Enrique Velazquez-Villarreal, lead author and assistant professor of translational genomics at Keck School of Medicine at USC. "Studying cancer at this higher resolution, we can discover information that lower-resolution bulk sequencing misses."

Their analysis revealed at least four major sub-populations of cells, also known as clones, that are expected to have, at some point during the cancer cell line's evolution, mutated from the original cancer cell.

The ability to identify sub-clones in cancer tissue could provide important biological insights into how cancer progresses, how it spreads and why it can become resistant to treatment.

"What if there's a small population of cells in a tumor that has acquired a change that makes them resistant to therapy? If you were to take that tumor and just grind it up and sequence it, you may not see that change," said John Carpten, PhD, study author and Co-Leader of the Translational and Clinical Sciences Program at the USC Norris Comprehensive Cancer Center, Chair of the Department of Translational Genomics, Keck School of Medicine, and Co-Director of the USC Institute for Translational Genomics. "If you go to the single cell level, you not only see it, but you can see the specific population of cells that has actually acquired that change. That could provide earlier access to the molecular information that could help define treatment approaches."

The researchers plan to share their data in the hope that more cancer researchers will focus on single-cell sequencing. They are also using their technique to study genetic diversity in clinical cancer specimens as a way to better understand the early molecular changes that lead to aggressive and tough-to-treat advanced cancers.

As far as humans are concerned, bacteria can be classified as either harmful, pathogenic bacteria and harmless or beneficial non-pathogenic bacteria. To develop better treatments for diseases caused by pathogenic bacteria, we need to have a good grasp on the mechanisms that cause some bacteria to be virulent. Scientists have identified genes that cause virulence, or capability to cause disease, but they do not fully know how bacteria evolve to become pathogenic.

To find out, Professor Chikara Kaito and his team of scientists from Okayama University, Japan, used a process called experimental evolution to identify molecular mechanisms that cells develop to gain useful traits, and published their findings in PLoS Pathogens. "We're excited by this research because no one has ever looked at virulence evolution of bacteria in an animal; studies before us looked at the evolution in cells," said Prof Kaito.

The scientists decided to start with a non-pathogenic Escherichia coli (or E. coli for short) and repeatedly mutate it and use it to infect silkworms, an insect that is often used as a model for infectious diseases, and then test whether it will cause death in silkworms.

Through this experiment, the scientists created E. coli strains with a 500-fold increased virulence compared to the original bacterial strain and found that mutations in the gene that code for one specific protein, the "lipopolysaccharide transporter (LPS) transporter," was one of the reasons for the increased virulence. This protein forms a part of the bacterial cell membrane and protects the bacteria from harm. Because of this, the LPS transporter is necessary for E. coli to grow.

The mutations that increased bacterial deadliness appeared to give E. coli resistance against some antibiotics, as well as some antibacterial substances from the silkworms. The reason for this is likely a corresponding increase in the concentration of structures called outer membrane vesicles, which the bacteria release to absorb harmful compounds to prevent them from entering the bacteria and harming them.

Researchers also identified the characteristics of substances that pathogenic strains were resistant to, showing that they were "hydrophobic" (or water-repelling) and positively charged. This fit with the increased amount of outer membrane vesicles, which are hydrophobic and negatively charged, allowing them to hold onto those substances (because, of course, opposite forces attract). The scientists also showed that the mutations occurred in parts of LPS transporter that are directly on the outside of the bacterial membrane. The scientists suspect that this is because these areas are more exposed to the environment, thereby experience more natural selection, and are thereby more susceptible to mutation.

"What we've done here is identify several things about pathogenic bacteria," explains Prof Kaito. "We showed for the first time that mutations to LPS transporter can increase virulence, and we provided evidence for how that virulence actually happens--the mutant bacteria make more outer membrane vesicles." And that's not all, the team also pinpointed specific structural changes to mutated LPS transporter that could explain why virulence is different across bacteria--because each species might have a different structure.

When asked about how his work contributes to scientific understanding and to medicine, Prof Kaito elaborates, "Before our study, it wasn't very clear how bacteria actually evolved properties that made them more harmful, so our study helps clarify this. An understanding of this process means the possibility of creating drugs or other therapy that can keep bacteria from becoming pathogenic, especially if we find more proteins like LPS transporter, where mutations can have such a big effect."

Of course, further studies are needed to explore whether the mutations observed in this study will also increase virulence when the bacteria infect animals bigger than silkworms, like mammals. But this study is definitely the first step toward unraveling the mystery of differences between dangerous and harmless bacteria.

How do environmental exposures during pregnancy and childhood influence the risk of obesity in children? The Barcelona Institute for Global Health (ISGlobal), a centre supported by the "la Caixa" Foundation, and the University of Southern California led the first major study to investigate the associations between many pollutants and environmental factors --77 prenatal and 96 childhood exposures-- and the risk of childhood obesity. The findings show that air pollution, smoking and certain characteristics of the built environment--such as high population density-- may play a role in the development of obesity in children.

To date, several studies have addressed the effect of environmental pollutants, lifestyle factors, and urban environment factors on childhood obesity, but they studied each single exposure separately. The exposome concept has changed the way we investigate how environmental risks affect health. Instead of analysing the possible health consequences of, exposome studies consider many different exposures a person faces altogether. This approach takes into account many elements we are exposed to through our diet, lifestyle and the environment where we live.

The new study, which forms a part of the HELIX project and was published in Environmental Health Perspectives, used data on more than 1,300 children aged 6 to 11 years from birth cohort studies in six European countries: France, Greece, Lithuania, Norway, Spain and the United Kingdom.

The authors used data on body mass index (BMI), waist circumference, skinfold thickness and body fat mass to determine the children's overweight and obesity status. Blood and urine samples from the children and their mothers during pregnancy were also analysed. In total, 77 pregnancy and 96 childhood exposures were assessed, including air pollutants, built environment, green spaces, smoking and chemical pollutants (persistent organic pollutants, heavy metals, phthalates, phenols and pesticides).

ISGlobal researcher Martine Vrijheid, who coordinates the HELIX project and was the first author of the study, commented: "The prevalence of childhood obesity is increasing at alarming rates across the globe and may have increased even more than usual during the COVID-19 lockdown period." The findings of the study, which used data collected before anti-COVID-19 measures were introduced, were in line with global trends: the combined prevalence of overweight and obesity was 29% for the study population as a whole, with higher percentages for the cohorts from Spain (43%) and Greece (37%).

The results showed that exposure to smoking (both maternal smoking during pregnancy and second-hand smoking during childhood), air pollution (PM2.5 and PM10 particulate matter and nitrogen dioxide, indoor and outdoor) as well as certain characteristics of the built environment were associated with a higher childhood BMI. Differences in socio-economic status did not explain these findings.

Associations with chemical pollutants were less consistent, with some chemicals measured in child blood (heavy metals copper and cesium) showing higher BMI, and others (persistent organic pollutants such as PCBs and DDE pesticides) showing lower BMI. This may be explained by the fact that chemicals were measured at the same time as obesity in the children, and obesity status may have influenced chemical blood levels. Longitudinal follow-up of the cohort is needed to establish this.

Obesity and Unwalkable Cities

"The children who live in densely populated areas and go to schools in areas with few services and facilities were more likely to be obese," commented Leda Chatzi, Professor of Preventive Medicine at the University of Southern California and last author of the study. The relationship between obesity and the characteristics of the built environment "is in line with the findings of previous research and could be explained by a lack of opportunities for children to walk or engage in other outdoor physical activities," she adds.

"These findings provide further evidence that modifying environmental exposures early in life can limit the risk of obesity and associated complications," commented Martine Vrijheid. "The implications for public health are important since these results may help to identify obesity-related exposures that could be targeted for prevention and intervention early in life." 

Funding: The study received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 308333 - the HELIX Project and the National Institute of Environmental Health Sciences NIEHS R21ES029681.

What The Study Did: This randomized clinical trial evaluates the effect of treatment with colchicine on cardiac and inflammatory biomarkers and clinical outcomes in patients hospitalized with COVID-19.

Authors: Spyridon G. Deftereos, M.D., Ph.D., of the National and Kapodistrian University of Athens in Greece, is the corresponding author.

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(doi:10.1001/jamanetworkopen.2020.13136)

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What The Article Says: A man in his 60s presented with numerous pseudovesicular papules on the trunk 12 hours after the initiation of treatment for COVID-19.

Authors: Laurence Toutous Trellu, M.D., of the Geneva University Hospitals in Switzerland, is the corresponding author.

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(doi:10.1001/jamadermatol.2020.1966)

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What The Article Says: This essay describes observations of the qualities developed by hospital staff members during the COVID-19 pandemic.

Author: Megha Prasad, M.D. M.S., of the Columbia University Irving Medical Center in New York, is the corresponding author.

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Life depends on an intricate game of hide-and-seek taking place inside the cell. New research, which is now published in the journal Nature, sheds light on the mechanisms with which DNA-binding proteins search the genome for their specific binding sites.

DNA is a double-helical molecule that stores all the instructions a cell requires to sustain itself. The information is encoded within the specific sequential order of genetic letters (DNA base pair sequence). Correctly implementing the vital instructions stored in this genetic code depends on the ability of proteins to recognise and selectively bind to specific DNA sequences. Such proteins include transcription factors, which have the crucial task of switching genes on and off by binding to specific transcription factor binding sites. Failure to engage these DNA target sites at the right place and time would have disastrous consequences for cellular life - genes would not be switched on when needed, while others might never turn off.

From the perspective of a transcription factor, finding its specific binding site amounts to finding the proverbial needle (i.e., short stretch of DNA, often around a dozen genetic letters only) in a haystack (the genome, ranging from millions to billions of letters depending on the organism). This so-called search problem has been studied extensively, and many proteins utilise a process termed facilitated diffusion to accelerate their search. Here, a protein undergoes three-dimensional diffusion (Brownian motion) until it randomly bumps into a DNA molecule. If the site of collision does not correspond to the correct binding site, the protein can undergo 1D diffusion by randomly sliding back-and-forth along the DNA before unbinding and returning to 3D diffusion. Scientists have long established that the 1D sliding process accelerates the search, but the precise mechanism of 1D sliding has remained enigmatic.

In this new study, led jointly by Uppsala University researchers Sebastian Deindl and Johan Elf, the 1D sliding mechanism takes centre stage.

"The molecular mechanism of the scanning process has been poorly understood, and it has remained a great mystery how transcription factors manage to slide fast on non-specific DNA sequences, yet at the same time bind efficiently to specific targets," says PhD student and joint first author Emil Marklund.

In order to tackle these questions, the two research teams developed new fluorescence microscopy imaging approaches to observe individual transcription factor proteins sliding along the DNA in real time as they search for and bind to the correct binding site.

"It is exciting that we were able to develop new imaging approaches to directly observe, for the first time, if and how often the sliding protein fails to recognise and slides past its binding site," says Deindl.

It turns out the sliding protein is quite sloppy and frequently misses its target site. In order to better understand how the sliding protein explores the DNA surface, a new way of tracking and shooting extremely fast movies of the rapidly sliding protein had to be developed. The protein searches the DNA very fast: 10 base pairs are scanned in around 100 microseconds (one microsecond corresponds to one millionth of a second). The researchers realised they needed to carry out much faster measurements than anyone had done before to investigate how the protein explores the DNA surface on these length- and timescales.

Using this new microscopy approach, the authors could follow the sliding protein's helical path around the DNA molecule.

"It's great that we can push the dynamic observation of bimolecular interactions to the sub-millisecond time scale - this is where the chemistry of life happens," says Elf.

The sliding protein turned out not to strictly follow the track given by the helical geometry of the DNA molecule itself. Instead, it was observed to slip out of its track quite frequently by making short hops.

"By hopping, the protein trades thorough scanning for speed, so it can scan DNA faster. This is a really smart choice by the protein, since it will find the target twice as fast using this search mechanism," says Marklund.

In a new study, published in the journal Nature, an international team of scientists provide the first conclusive evidence directly linking deep Earth's water cycle and its expressions with magmatic productivity and earthquake activity.

Water (H2O) and other volatiles (e.g. CO2 and sulphur) that are cycled through the deep Earth have played a key role in the evolution of our planet, including in the formation of continents, the onset of life, the concentration of mineral resources, and the distribution of volcanoes and earthquakes.

Subduction zones, where tectonic plates converge and one plate sinks beneath another, are the most important parts of the cycle - with large volumes of water going in and coming out, mainly through volcanic eruptions. Yet, just how (and how much) water is transported via subduction, and its effect on natural hazards and the formation of natural resources, has historically been poorly understood.

Lead author of the study, Dr George Cooper, Honorary Research Fellow at the University of Bristol's School of Earth Sciences, said:
"As plates journey from where they are first made at mid-ocean ridges to subduction zones, seawater enters the rocks through cracks, faults and by binding to minerals. Upon reaching a subduction zone, the sinking plate heats up and gets squeezed, resulting in the gradual release of some or all of its water. As water is released it lowers the melting point of the surrounding rocks and generates magma. This magma is buoyant and moves upwards, ultimately leading to eruptions in the overlying volcanic arc. These eruptions are potentially explosive because of the volatiles contained in the melt. The same process can trigger earthquakes and may affect key properties such as their magnitude and whether they trigger tsunamis or not."

Exactly where and how volatiles are released and how they modify the host rock remains an area of intense research.

Most studies have focused on subduction along the Pacific Ring of Fire. However, this research focused on the Atlantic plate, and more specifically, the Lesser Antilles volcanic arc, located at the eastern edge of the Caribbean Sea.

"This is one of only two zones that currently subduct plates formed by slow spreading. We expect this to be hydrated more pervasively and heterogeneously than the fast spreading Pacific plate, and for expressions of water release to be more pronounced," said Prof. Saskia Goes, Imperial College London.

The Volatile Recycling in the Lesser Antilles (VoiLA) project brings together a large multidisciplinary team of researchers including geophysicists, geochemists and geodynamicists from Durham University, Imperial College London, University of Southampton, University of Bristol, Liverpool University, Karlsruhe Institute of Technology, the University of Leeds, The Natural History Museum, The Institute de Physique du Globe in Paris, and the University of the West Indies.

"We collected data over two marine scientific cruises on the RRS James Cook, temporary deployments of seismic stations that recorded earthquakes beneath the islands, geological fieldwork, chemical and mineral analyses of rock samples, and numerical modelling," said Dr Cooper.

To trace the influence of water along the length of the subduction zone, the scientists studied boron compositions and isotopes of melt inclusions (tiny pockets of trapped magma within volcanic crystals). Boron fingerprints revealed that the water-rich mineral serpentine, contained in the sinking plate, is a dominant supplier of water to the central region of the Lesser Antilles arc.

"By studying these micron-scale measurements it is possible to better understand large-scale processes. Our combined geochemical and geophysical data provide the clearest indication to date that the structure and amount of water of the sinking plate are directly connected to the volcanic evolution of the arc and its associated hazards," said Prof. Colin Macpherson, Durham University

"The wettest parts of the downgoing plate are where there are major cracks (or fracture zones). By making a numerical model of the history of fracture zone subduction below the islands, we found a direct link to the locations of the highest rates of small earthquakes and low shear wave velocities (which indicate fluids) in the subsurface," said Prof. Saskia Goes.

The history of subduction of water-rich fracture zones can also explain why the central islands of the arc are the largest and why, over geologic history, they have produced the most magma.

"Our study provides conclusive evidence that directly links the water-in and water-out parts of the cycle and its expressions in terms of magmatic productivity and earthquake activity. This may encourage studies at other subduction zones to find such water-bearing fault structures on the subducting plate to help understand patterns in volcanic and earthquake hazards," said Dr Cooper.

"In this research we found that variations in water correlate with the distribution of smaller earthquakes, but we would really like to know how this pattern of water release may affect the potential - and act as a warning system - for larger earthquakes and possible tsunami," said Prof. Colin Macpherson.

An exoplanet the size of Neptune has been discovered around the young star AU Microscopii, thanks in part to the work of Jonathan Gagné, a former iREx Banting postdoctoral researcher who is now a scientific advisor at the Rio Tinto Alcan Planetarium.

Astrophysicists have been searching for exoplanets in this system, a unique laboratory for studying planetary formation, for more than a decade. The breakthrough, announced today in Nature, was made possible in part by NASA's TESS and Spitzer space telescopes.

Located about 32 lightyears from Earth, AU Microscopii, or AU Mic, is a young star between 20 and 30 million years old, which is about 180 times younger than our own Sun. In the 2000s, it was found to still be surrounded by a large disc of debris, a remnant of its formation. Since then, astrophysicists have been actively searching for planets around AU Mic, since it is within such discs of dust and gas that they form.

"AU Mic is a small star, with only about 50 per cent of the Sun's mass," said Gagné, who participated in the observations and data processing. These stars generally have very strong magnetic fields, which make them very active. That explains in part why it took nearly 15 years to detect the exoplanet, called AU Mic b. The numerous spots and eruptions on the surface of AU Mic hampered its detection, which was already complicated by the presence of the disc."

A big challenge

Jonathan Gagné at the summit of Mauna Kea, where astrophysicists have been searching for a planet around AU Mic since 2010. Credit : Jonathan Gagné. In 2010, a team led by Peter Plavchan, now an assistant professor at George Mason University, began observing AU Mic from the ground using NASA's Infrared Telescope Facility (IRTF).

The telescope operates in the infrared, where the team hoped to see the signal of the planet better, since the star's activity is less intense in this type of light.

For his part, Gagné made numerous observational trips to the IRFT during his doctoral studies. That is when he became involved in the project. "A few years after I joined the team, we noticed a possible periodic variation in the radial velocity of AU Mic," he recalled.

"We were thus made aware of the plausible presence of a planet around it." As a planet orbits, its gravity tugs on its host star, which moves slightly in response. Sensitive spectrographs such as the one on the IRTF can detect the star's radial velocity, its motion to-and-fro along our line of sight.

Space telescopes to the rescue

The accuracy of the data obtained on the ground was unfortunately not sufficient to confirm without a doubt that the signal was due to an exoplanet. It's thanks to the transit m ethod, a different detection technique, that the team was finally able to confirm the presence of AU Mic b.

A transit occurs when a planet passes directly between its host star and the viewer, periodically hiding a small fraction of its light. Astronomers observed two transits of AU Mic b during NASA's Transiting Exoplanet Survey Satellite (TESS) first mission, in the summer of 2018. They then observed two more with NASA's Spitzer Space Telescope in 2019.

Since the amount of light blocked depends on the size of the exoplanet and its distance from its star, these observations allowed scientists to determine that AU Mic b is about the size of Neptune, and that it passes in front of its star every 8.5 days.

Thanks to previous ground-based observations, the team also has a partial constraint on the mass of AU Mic b. Combining IRTF's observations with data obtained at the European Southern Observatory in Chile and the W. M. Keck Observatory in Hawai'i, they concluded that its mass is less than about 3.4 times the mass of Neptune (or 58 times that of Earth).

A unique laboratory

AU Mic provides a unique laboratory to determine how exoplanets and their atmospheres form, and how they interact with the disc of debris and gas from which they are born.

Scientists are excited about their latest discovery, as very few systems like AU Mic are known. Not only is the detection of exoplanets difficult in these systems, but they are also very rare because a system's period of planetary formation is relatively short compared to the life of a star.

The AU Mic system is close to Earth and therefore appears brighter, allowing astrophysicists to observe it with a range of instruments. such as the SPIRou spectrograph.

"This instrument, with its polarimetric capabilities, will allow us to better distinguish the effects of stellar activity, which are often confused with the signal from the planets," said É tienne Artigau, a project scientist at Université de Montréal. "This will allow us to determine the mass of AU Mic b accurately and to know if this exoplanet is more like a large Earth or a Neptune twin."

Other iREx astronomers are enthusiastic about trying to detect the planet's atmosphere, and see the effect of the active star on it. These observations can also be accomplished with SPIRou.

AU Mic is part of an association of young stars that formed at about the same time in the same place. Beta Pictoris, the star that gives its name to this association, also has a disc and two known planets.

Both the star and the planets are however considerably more massive (1.75 times the mass of the Sun, and 11 and nine times the mass of Jupiter, respectively). They do not appear to have evolved in the same way as AU Mic and its planet. Studying these two systems, which have many characteristics in common, scientists can compare two very different scenarios of planetary formation.

Many surprises undoubtedly still hide within AU Mic's system, the iREX researchers believe. Will further observations of the system with TESS confirm the existence of other planets? Is the atmosphere of the planet outgassing because of the strong stellar activity? How does this system compare to others of the same age? Those are all questions for future study.

New research published today in Nature reports the discovery of a planet about the size of Neptune orbiting an especially young, nearby star. The planet, named AU Mic b, is orbiting AU Microscopii, which is relatively close to the Milky Way at 31.9 light years away. AU Microscopii is also "only" 20 or 30 million years old--at least 150 times younger than our Sun.

There are only two or three known stars that are both nearby and young, and scientists have been searching for planets orbiting them for at least a decade. This means the new finding creates a major opportunity for breakthrough research into solar system formation dynamics.

"One of the things we want to understand is, 'When do planets form, and what do they do in their early days?'" says Tom Barclay. He's an associate research scientist with UMBC's Center for Space Sciences and Technology, a partnership with the NASA Goddard Space Flight Center in Greenbelt, Maryland.

Because AU Mic b is so young, Barclay adds, "studying this planet, and hopefully others like it, can give us insight into how our own solar system formed."

Shining light on a new planet

Barclay primarily works on NASA's Transiting Exoplanet Survey Satellite (TESS) mission. TESS observes the same section of sky for weeks at a time, collecting data about the brightness of stars in its field of view every two minutes. Thanks to this constant watchfulness, TESS can help detect planets by recording when a star's brightness temporarily dims. That can sometimes signal a planet crossing in front of the star, or "transiting."

"My role is to take the brightness data for the star and use that to understand what the size and other properties of the planet are," says Barclay, who is second author on the new paper. Peter Plavchan of George Mason University leads the project. "Dips in brightness tell you about the size of the planet, and measuring how regularly spaced the transits are tells us how long it takes the planet to go around the star," Barclay explains.

TESS detected two transits of AU Mic b, but the research team needed a third to "be confident that what we'd seen wasn't something else in the data trying to fool us," Barclay says. So they called on additional data collected by NASA's Spitzer satellite and ground-based instruments in Hawaii and Chile.

Barclay analyzed the combined information and was able to confirm that AU Mic b has a mass of no more than 58 Earths and completes an orbit of AU Microscopii every 8.5 days. An orbit that short indicates that the planet is extremely close to the star.

Discovery dominoes

Next, Barclay and his colleagues want to learn more about the atmosphere of the new planet. Because it only recently formed, "it may well be losing its atmosphere at a rate that we can see," Barclay says. "It might even appear somewhat teardrop-shaped, as the planet is moving and leaving some of its atmosphere behind. So we're going to go and look for that."

In addition to the rate of atmosphere loss, careful observations can also help determine what the planet's atmosphere is made of. Determining the atmosphere's components could help the team figure out where the planet formed, because certain substances can only exist at a known distance from the star.

Knowing where the planet formed would provide clues about how it had moved since it first came into being. And knowing that would get scientists closer to understanding more generally how planets form and migrate in a new solar system.

Planet migration puzzle

AU Mic b is likely primarily comprised of gases. "This star probably hasn't had time to form small, rocky planets yet," Barclay says. "It gives us a chance to get a picture of what might have happened before our own terrestrial planets like Earth and Venus formed."

But the work is not easy. "Understanding the migration of planets is a really difficult problem. One of the fun things and one of the most frustrating things about studying stars is that we can never go to them," Barclay says. "So this discovery is just one more puzzle piece in trying to understand what's going on."

Cannabidiol, a type of medicinal cannabis, may reduce severe behavioural problems in children and adolescents with an intellectual disability a new study has found.

The pilot study, led by the Murdoch Children's Research Institute (MCRI) and published in the British Journal of Clinical Pharmacology, recorded a clinically significant change in participants' irritability, aggression, self-injury, and yelling. The intervention was also found to be safe and well-tolerated by most study participants.

The randomised controlled trial involved eight participants, aged 8-16, years who took either cannabidiol or a placebo over eight weeks. Participants were recruited from paediatric clinics from both hospital and private paediatric practices.

Although the pilot study was not large enough to make definitive statements, the early findings strongly support a larger follow-up trial. Only a large scale randomised controlled trial can produce the definitive results necessary to drive changes in prescribing and clinical care guidelines. The researchers are planning a large study to definitively test the findings.

The researchers are also seeking funding for further research into the effectiveness of medicinal cannabis in children with developmental disorders such as autism and Tourette syndrome.

Associate Professor Daryl Efron, a clinician-scientist at MCRI who led the study, said this was the first investigation of cannabidiol to manage severe behavioural problems in children and adolescents with an intellectual disability. Most of the participants also had autism.

The study found the medication was generally well-tolerated and there were no serious side effects reported. All parents reported they would recommend the study to families with children with similar problems.

Associate Professor Efron said severe behavioural problems such as irritability, aggression and self-injury in children and adolescents with an intellectual disability were a major contributor to functional impairments, missed learning opportunities and reduced quality of life.

He said conventional psychotropic medications, including anti-psychotics and anti-depressants, were prescribed by Australian paediatricians for almost half of young people with an intellectual disability, despite limited evidence of their effectiveness. Given how extremely difficult behavioural problems were to treat in these patients, new, safer interventions were needed to treat this highly vulnerable patient group, he said.

"Current medications carry a high risk of side-effects, with vulnerable people with intellectual disability being less able to report side-effects," he said. "Common side-effects of antipsychotics, such as weight gain and metabolic syndrome, have huge health effects for a patient group already at increased risk of chronic illness."

Cannabidiol is already being used increasingly to manage a range of medical and psychiatric conditions in adults and epilepsy in children.

Associate Professor Efron said there was intense interest from parents and physicians in medicinal cannabis as a treatment for severe behavioural problems in youth with an intellectual disability.

"Parents of children with an intellectual disability and severe behavioural problems are increasingly asking paediatricians whether they can access medicinal cannabis for their child and some parents have reported giving unregulated cannabis products to their children," he said.

"We are also finding many physicians feel unprepared to have these conversations with their patients."
Researchers from The Royal Children's Hospital, the University of Melbourne and Monash University also contributed to the study.