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HAMILTON, ON (Nov. 19, 2019) - There has been interest in cannabis being used as a replacement drug for people with opioid use disorder, but research at McMaster University has found it doesn't work.

The research team looked at all research on the effects of cannabis use on illicit opioid use during methadone maintenance therapy, which is a common treatment for opioid use disorder, and found six studies involving more than 3,600 participants.

However, a meta-analysis of the studies found cannabis use didn't reduce illicit opioid use during treatment nor did it retain people in treatment.

The study was published today in the Canadian Medical Association Journal.

"There is limited evidence that cannabis use may reduce opioid use in pain management, and some high-profile organizations have suggested cannabis is an 'exit drug' for illicit opioid use, but we found no evidence to suggest cannabis helps patients with opioid use disorder stop using opioids," said senior author Dr. Zainab Samaan, associate professor of psychiatry and behavioural neurosciences at McMaster and a Hamilton staff psychiatrist.

Electricity supply is one of the biggest CO2 emitters globally. To keep global warming well below 2°C, several paths lead to zero emissions in the energy sector, and each has its potential environmental impacts - such as air and water pollution, land-use or water demand. Using a first-time combination of multiple modelling systems, an international team of researchers led by the Potsdam Institute for Climate Impact Research (PIK) has now quantified the actual benefits and downsides of three main roads to decarbonisation. They show that relying mainly on wind and solar would bring most co-benefits for the health of people and planet. Switching to carbon capture and storage in combination with fossil and biomass resources, in turn, is likely to convey significant environmental costs by devouring large areas at the cost of biodiversity, and by releasing pollutants to the environment.

"A main winner of decarbonisation is human health"

"When looking at the big picture - from the direct emissions of power installations, to the mining of minerals and fuels for their construction and operation, to the lands necessary for the energy supply infrastructure - we found that the best bet for both people and environment is to rely mainly on wind and solar power," Gunnar Luderer explains. He is lead author and deputy chair of PIK's research domain on transformation pathways. "A main winner of decarbonisation is human health: switching to renewables-based electricity production could cut negative health impacts by up to 80 per cent. This is mainly due to a reduction of air pollution from combusting fuels. What is more, the supply chains for wind and solar energy are much cleaner than the extraction of fossil fuels or bioenergy production."

For their study published in Nature Communications, the authors compared three scenarios of decarbonising the power sector by 2050: One focused mainly on solar and wind power, a second relying mainly on carbon capture and storage in combination with biomass and fossils, and a third route with a mixed technology portfolio. In all scenarios, land use requirements for power production will increase in the future. By far the most land-devouring method to generate electricity is bioenergy. "Per kilowatt hour of electricity from bioenergy, you need one hundred times more land than to harvest the same amount from solar panels", Alexander Popp, head of the land use management group at the Potsdam Institute, lays out. "Land is a finite resource on our planet. Given the growing world population with a hunger for both electricity and for food, pressures on the land and food systems will increase, too. Our analysis helps to get the magnitudes right when speaking of the at times much-hailed technology of bioenergy."

"Shifting from a fossil resource base to a power industry that requires more land and mineral resources"

The researchers used complex simulations sketching out the possible paths of decarbonising the electricity supply (Integrated Assessment Modelling) and combined their calculations with life cycle analyses. Anders Arvesen from the Norwegian University of Science and Technology (NTNU) says: "In combining two pairs of analytical spectacles, we were able to look at a wide range of environmental problems, from air pollution to toxicants, from finite mineral resources needed to manufacture wind turbines to the extent of lands transformed into bioenergy plantations if relying on negative emissions. This is a promising approach also to tackle other sectors, like buildings or the transport sector."

"Our study delivers even more very good arguments for a rapid transition towards a renewable energy production. However, we need to be aware that this essentially means shifting from a fossil resource base to a power industry that requires more land and mineral resources," adds Luderer. "Smart choices are key to limiting the impact of these new demands on other societal objectives, such as nature conservancy, food security, or even geopolitics."

Producing electricity in a climate-friendly brings huge benefits for our health - mainly due to a reduction of air pollution from combusting fuels.

Complications following a procedure to treat tongue-tie in babies are occurring that can result in admission to hospital, something a University of Otago paediatrician says needs to be better understood by both health practitioners and parents.

Paediatrician, Associate Professor Ben Wheeler, and his team of researchers from the New Zealand Paediatric Surveillance Unit recently undertook a survey which shows complications including breathing problems, pain, bleeding, weight loss and poor feeding occurred in babies following minor surgery for tongue-tie (ankyloglossia).

Tongue-tie is a condition in infants which can often interfere with successful breastfeeding. A simple procedure called frenotomy is used to treat the condition and is performed by a range of health practitioners including midwives, doctors and dentists. While traditionally it has been performed with scissors, there is a trend for the use of a laser.

"Many people think this is a simple and completely safe procedure, but we think families and healthcare providers considering this procedure should be fully informed that it can carry potential downsides as well as benefits," Associate Professor Wheeler explains.

"All surgery, even when minor, is not risk-free."

He is also concerned more infants are undergoing the procedure than necessary. "Potentially 10 to 20 per cent of all infants in New Zealand are having it done where, in fact, more like 3 per cent would actually benefit from it."

This is the first study internationally to report complications relating to tongue-tie procedures in babies and has just been published in the Australasian scientific journal, Journal of Paediatrics and Child Health.

Over a two year period up until July 2018, there were 23 notifications of complications relating to frenotomy in infants aged under one, from 17 paediatricians in New Zealand. Most related to poor feeding (44 per cent), respiratory events (25 per cent), bleeding and weight loss (both 19 per cent). While frenotomy rates in New Zealand are unknown, rates of up to 20 per cent of all babies born in some provinces have been reported. The researchers estimate about 20 out of every 100,000 babies born will suffer a complication related to the procedure.

Associate Professor Wheeler says the research showed complications following frenotomy are occurring that require assessment and admission by hospital-based paediatricians in New Zealand, with a significant geographical variation.

For example, one healthcare provider in Dunedin treated 414 babies (12 per cent of all babies born) in the Otago/Southland regions over one year, while in Canterbury where there are local evidence-based guidelines for referral, assessment and treatment of tongue-tie, frenotomy rates declined from 11.5 per to 3.6 per cent over a two-year period.

There is also an undue focus on a potential tongue-tie as a cause for poor feeding, which may cause undue delay in diagnosis and management of other potential causes of poor feeding, such as an underlying medical condition, Associate Professor Wheeler says.

"Respiratory complications such as apnoea (cessation of breathing) are also occurring following frenotomy in community settings that may not be equipped to deal with these."

The researchers concluded that practitioners conducting frenotomy need to be aware of the broad spectrum of potential complications that were encountered in this study, while parents and families need to be advised accordingly and steps taken to actively minise the risk of these complications occurring.

Centralised guidelines relating to referral, assessment and treatment such as those developed in Canterbury, together with specialist second opinions should be considered as the ideal model, Associate Professor Wheeler says.

The discovery of gases released from deep beneath the Earth's crust could help to explain Southern Africa's unusual landscape, a study suggests.

Scientists have long puzzled over why areas such as South Africa's Highveld region are so elevated and flat, with unexpectedly hot rocks below the surface.

Geologists have revealed that carbon dioxide-rich gases bubbling up through natural springs in South Africa originate from a column of hot, treacle-like material - called a hotspot - located deep inside the Earth.

Hotspots are known to generate volcanic activity in Hawaii, Iceland and Yellowstone National Park. In South Africa, the hotspot pushes the crust upwards, generating the distinctive landscape, which consists mostly of tablelands more than one kilometre above sea level, the researchers say.

This also explains why rocks beneath the region are hotter than expected - a property that could be harnessed to generate geothermal energy.

A team led by scientists from the University of Edinburgh analysed the chemical make-up of gas emerging from a deep crack in the Earth's crust located in KwaZulu-Natal, South Africa.

They found that variants of the elements helium and neon present in the gas match the composition of a rocky layer 1,000 kilometres below Earth's surface - called the deep mantle.

The findings provide the first physical evidence that Southern Africa lies on top of a plume of abnormally hot mantle, which had until now only been theorised using computer modelling of seismic data.

The study, published in the journal Nature Communications, was funded by the Engineering and Physical Sciences Research Council and the Natural Environment Research Council.

The research was completed with support from Scottish Carbon Capture and Storage and the UK Carbon Capture and Storage Research Centre. It also involved scientists from the Universities of Aberdeen and Strathclyde, Scottish Universities Environmental Research Centre, British Geological Survey and South Africa Council for Geoscience.

Dr Stuart Gilfillan, of the University of Edinburgh's School of GeoSciences, who led the study, said: "The high relief and hotter than expected subsurface temperatures of the rocks beneath Southern Africa had been a puzzle for geologists for many years. Our findings confirm that carbon dioxide gas at the surface is from a deep mantle plume, helping to explain the regions unusual landscape."

The South Pole-Aitken (SPA) is the largest and deepest basin on the Moon, theoretically opening a window into the lunar lower crust and likely into the upper mantle. However, compositional information of the SPA basin was mainly obtained from orbital remote sensing. Chang'E-4 landed in the SPA Basin, providing a unique chance for in situ probing the composition of the lunar interior. The landing site is located on ejecta strips radiating from Finsen crater, which lies ~135 km to the northeast. The lunar surface at the landing site consists of very homogenous regolith overlain by few scattered rocks.

A surface rock and the lunar regolith at 10 sites along the rover Yutu-2 track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission operations. In-situ spectra of the regolith have peak band positions at 1 and 2 μm, similar to the spectral data of Finsen materials from the Moon Mineralogy Mapper, which confirms that the regolith's composition of the landing area is mostly similar to that of Finsen ejecta. The estimated modal composition of the lunar regolith is dominated by agglutinates, plagioclase and pyroxenes with more low-calcium than high-calcium, inconsistent with mare basalts. Thus, the surface materials at the landing site are predominantly ejecta from neighboring craters, with little contribution from the underlying mare basalt. Our observations are also supported by topographic features.

The rock spectrum shows similar band peak positions, but stronger absorptions, suggesting relatively fresh exposure. This rock is likely representative of the original bedrock in the Mg-Pyroxene Annulus of SPA basin. This rock is >20 cm in size, sitting on the regolith surface. No grains can be unambiguously recognized on the surface based on the image with spatial resolution of 0.6mm/pixel, suggesting a fine- or medium-grain-size texture (

15-meter high waves that pushed boulders the weight of a Leopard tank inland: This is more or less how one can imagine the tsunami that hit the coast of today's Sultanate of Oman about 1,000 years ago, as concluded by a recent study by the universities of Bonn, Jena, Freiburg and RWTH Aachen. The findings also show how urgently the region needs a well-functioning early warning system. But even then, coastal residents would have a maximum of 30 minutes to get to safety in a similar catastrophe. The study will be published in the journal "Marine Geology", but is already available online.

Oman lies in the east of the Arabian Peninsula. The coasts of the Sultanate are repeatedly struck by tsunamis, most recently in 2013. Even with the most severe of these in recent times, the Makran event in 1945, the damage remained comparatively low. Back then, the tidal wave reached a height of three meters.

The scientists have now discovered evidence of a tsunami which is likely to have been much more powerful, with waves of up to 15 meters. For this purpose, the researchers from Bonn, Jena and Aachen concentrated their terrain investigations on a 200-kilometer coastal strip in northeastern Oman. "There we identified 41 large boulders, which were apparently carried inland by the force of the water," explains Dr. Gösta Hoffmann from the Institute for Geosciences at the University of Bonn.

Quartz clock in the rock

Some of the boulders were probably formed when the tsunami shattered parts of the cliffs; for one of them, the largest weighing around 100 metric tons, scientists were even able to determine the exact point at which it broke off. Others show traces of marine organisms such as mussels or oysters that cannot survive on land. "Certain methods can be used to determine their time of death," says the geologist Gösta Hoffmann. "This allowed us to establish when the boulders were washed ashore."

The quartz crystals in the rock also represent a kind of clock: They provide information about the last time they were exposed to the sun. This allowed the scientists to deduce how long the rocks had been in the place where they were found. The scientists from Freiburg are specialists in this method. "Many of these measurements gave us a value of about 1,000 years," emphasizes Hoffmann. "This corresponds well with the dating results of clay fragments we found in tsunami sediments. They originate from vessels used by coastal dwellers."

The Arabian and Eurasian tectonic plates collide in the Arabian Sea. They move towards each other at a speed of about four centimeters per year. During this process, one plate slides beneath the other. Sometimes they get stuck in this subduction zone. This can cause tensions that intensify more and more over years and decades. If they suddenly come loose with a violent jolt, the water column above the plates starts to move. This can lead to the extremely destructive waves that are characteristic of tsunamis.

"So far it has been unclear to what extent the Arabian and Eurasian plates get stuck," says Hoffmann. At the Makran event of 1945, for example, the effects were locally confined. The current findings, however, suggest that the tensions can also build up and unload on a very large scale - there is no other feasible explanation for the enormous forces at work at the time. "It is therefore extremely important that a tsunami early warning system is put in place for this region," stresses the geologist.

Nevertheless, even a smaller tsunami would have devastating consequences today: A large part of the vital infrastructure in the Sultanate of Oman has been built near the coast, such as the oil refineries and seawater desalination plants. A well-functioning warning system can, however, at least give residents some time to get to safety. Not very much though: Tsunamis move at the speed of a passenger aircraft; in the best case, the time between the alarm and the wave's impact would therefore be little more than 30 minutes.

Embryonic stem cells (ESCs) are distinguished by their dual ability to self-renew and their potential to differentiate, both of which require tight regulatory control. During the differentiation of ESCs, various cells develop into specialised cell types such as skin cells, nerve cells, muscle cells, etc. While our understanding of ES cell regulation has been dominated by transcriptional and epigenetic models, the role of post-transcriptional regulation via nuclear RNA decay has remained less explored.

Now a Danish research team has identified a disruptive relationship between excess nuclear RNA levels, regulated by the PolyA-tail eXosome Targeting' (PAXT) connection, and transcriptional control by the Polycomb Repressive Complex 2 (PRC2). The researchers propose that excess RNA hampers PRC2 function through its sequestration from DNA. Their results highlight the importance of balancing nuclear RNA levels and demonstrate the capacity of bulk RNA to regulate chromatin-associated proteins.

Previously, the Torben Heick Jensen Laboratory had identified and characterised the PAXT connection as an adaptor complex that targets polyadenylated (pA+) RNAs to the nuclear RNA exosome for decay (Read more). Upon depletion of PAXT components, including the zinc-finger protein ZFC3H1, cells stabilise and accumulate pA+ RNAs. This allows an approach to study the general effects of excess pA+ RNA in the nucleus.

Interestingly, removal of the PAXT component ZFC3H1 using CRISPR/Cas9 in mouse ESC subsequently disrupted their ability to differentiate. High throughput sequencing analysis revealed that Zfc3h1-/- knockout (KO) ES cells showed increased expression of differentiation associated RNAs that are usually silenced by the PRC2 complex. Upon further investigation, it was shown that the function and stability of the PRC2 complex was compromised due to excess binding of RNA as a consequence of Zfc3h1-/- KO. Together, this highlights the importance of maintaining a stable nuclear transcriptome through active RNA decay to prevent off-target effects as a result of RNA accumulation.

These findings are a result of a collaborative project between the laboratories of Torben Heick Jensen at the Department of Molecular Biology and Genetics, Aarhus University, and Kristian Helin at the Biotech Research and Innovation Centre, Copenhagen University, financed by the Novo Nordisk Foundation Center for Stem Cell Biology (DanStem) to investigate the role of RNA regulation in ES cell biology. The studies are primarily carried out by Will Garland from Aarhus University.

This study was published in the internationally recognised journal Cell Reports.

Researchers from McMaster University have discovered striking variation in the underlying genetic machinery that orchestrates sexual differentiation in frogs, demonstrating that evolution of this crucial biological system has moved at a dramatic pace.

A team of biologists examined more than two dozen species of Pipidae, a family of frog found in tropical South America and sub-Saharan Africa, which includes African clawed frogs, a smooth-skinned frog with webbed feet and claws on the hind legs.

They used modern techniques to study a gene known to trigger female development, dm-w, in over 20 species, each of which have both males and females, and requires sexual reproduction to breed.

Researchers discovered that the genes governing sexual selection differed radically across species.

"Sexual differentiation is fundamentally important in an evolutionary context," says Ben Evans, lead author of the study and a professor of biology at McMaster University.

"Once you have a system that works so well, one might expect that natural selection would guard against changes to that system. This is why it's so surprising that the genetic basis for sexual differentiation in fact evolved extremely rapidly in pipid frogs," he says.

The team found at least seven different systems in place for regulating sex determination across closely related species. Evans explains that three underlying mechanisms within the developmental systems are at work.

In some species, female frogs lost dm-w and use another, unknown gene to determine sex, suggesting dm-w stopped functioning over time. In other frog families, scientists were surprised to find the gene was present in both sexes, suggesting the function of gene became sidelined. In yet other species, dm-w became empowered into a potent female-specific sex determining gene.

"The results of this study," says Evans. "reminds us that evolution happens no matter how important a certain mechanism or trait might be."

Research from Florida State University is giving physicians a better understanding of ketamine, a potentially useful tool in treating depression that still has unanswered questions.

A team of researchers working in the laboratory of Mohamed Kabbaj, a professor of Biomedical Sciences and Neuroscience in the College of Medicine, showed that ketamine can decrease alcohol consumption in male rats that previously had consumed high amounts of alcohol when given unrestricted access several times a week. The neuroscience journal eNeuro published the research in its November edition.

There are no perfect treatments for alcoholism, Kabbaj said. Many patients relapse within a year after treatment.

"What makes ketamine interesting in our study is that it reduced alcohol intake, and the effect was long-lasting even after we stopped ketamine treatment," he said.

Ketamine is a promising frontier in psychiatric treatment. Existing antidepressants don't work for all patients, so scientists are looking for other effective options. Ketamine is one possibility. In March 2019, the U.S. Food and Drug Administration approved a nasal spray that includes a form of ketamine for use on patients with depression who didn't respond to other treatments.

But doctors still have questions about how ketamine works. This latest research is one piece of a larger investigation by Kabbaj's team to learn more about the drug, specifically its interactions with alcohol, the number one drug abused by depressed patients.

In this study, researchers examined how ketamine affected the rats' alcohol consumption and how that alcohol intake affected their self-administration of ketamine.

The major finding in the study was that high-alcohol intake male rats displayed a significant reduction in alcohol consumption after a regimen of ketamine compared to rats that received a saline solution. The effect lasted for at least three weeks even after stopping ketamine treatment, suggesting a long-term benefit of ketamine in reducing alcohol use.

"Three weeks is a long time in a rat's life," Kabbaj said. "If a similar thing happened in humans, one could imagine that after a short treatment with ketamine, alcoholic patients would cease alcohol intake for a couple of years. That would be a great achievement."

Ketamine didn't affect high-alcohol female rats, and interestingly, it increased drinking in low-alcohol females. Researchers said clinical studies for men and for women are needed before ketamine is used as a therapy for alcoholism in either sex.

Current cancer treatment courses often begin with tissue biopsies. Biopsies, however, which involve the physical resection of a small tissue sample, can lead to localized tissue injury, bleeding, inflammation, and stress, as well as increased risk of metastasis.

New technology developed by a team of researchers from Tel Aviv University (TAU), Herzliya Interdisciplinary (IDC), and Technion-Israel Institute of Technology may soon offer an alternative means of profiling tissues. The research finds that electroporation -- the application of high voltage pulsed electric fields to tissues -- enables minimally invasive extraction of RNA and proteins that reveal tissue-specific differential expression critical to molecular profiling.

"Our new method can enhance the information surgeons obtain from biopsy, for example," explains Prof. Alexander Golberg of TAU's Porter School of Environment and Earth Sciences, a lead author of the study. "By harvesting molecules from suspicious areas, this method enables improved diagnostics of the site and produces information pertinent to treatment decisions, including molecular biomarkers."

Research for the study was conducted by TAU graduate student Julia Sheviryov, Dr. Oz Solomon of IDC, Leon Anavy of the Technion, and Prof Zohar Yakhini from IDC and the Technion. The research was published in Scientific Reports on October 31.

By extracting tissue-specific molecules using a combination of high-voltage and short pulses applied to specific sites, the technology enables profiling RNA, proteins, or metabolites in tissue and tissue environments. This can improve the accuracy of tumor diagnostics, including the potential response to different therapies.

For the research, the scientists used electroporation to extract proteins and RNA from several normal human tissues, including liver tissues, and from a liver cancer model in mice. They then used advanced bioinformatics tools to demonstrate that tissue types can be distinguished by identifying specific molecules in the extracted samples.

"Further in vivo development of extraction methods based on electroporation can drive novel approaches to the molecular profiling of tumors and tumor environments, and thereby to related diagnosis practices," Prof. Golberg concludes. "Now we have a new method with which to sample tissue in vivo. We can sample molecules without extracting cells and without the risky excision of tissue parts."

The researchers now plan to develop a device for local extraction, thus enabling tumor heterogeneity mapping and the in vivo probing of tumor environment molecular composition.

Managing reservoirs for water quality, not just flood control, could be part of the solution to the growth of toxic algal blooms in the Great Lakes, especially Lake Erie, every summer.

In a major study involving data from Canada and the United States, researchers at the University of Waterloo identified reservoirs on streams and rivers as sources of food for algae at the worst possible time.

The culprit is dissolved phosphorus released from upstream reservoirs when warm lake water is ideal for the growth of algal blooms, which can cause illness and contaminate water supplies.

"Algae love dissolved phosphorus and when it arrives in the summer, it arrives exactly when they want it the most," said Nandita Basu, a professor of civil and environmental engineering at Waterloo.

Dissolved phosphorus, which comes primarily from fertilizer, is generally expected only at low levels in rivers and streams in summer following the peak snow-melt in spring.

But researchers found unusually high summer levels of dissolved phosphorus in areas with reservoirs, which are created by damming rivers and streams to hold water back to prevent flooding.

Basu, also a professor of earth and environmental sciences and a member of the Water Institute at Waterloo, said reservoirs store phosphorus that has been washed off farm fields in sediment.

In the warm summer months, that stored phosphorus is released from the sediment and increases dissolved phosphorus concentrations in water flowing downstream.

"Our work shows reservoirs can play a significant role," said Basu, who analyzed data from more than 200 testing locations in Great Lakes watersheds. "They take in phosphorus that is attached to soil particles and release dissolved phosphorus that encourages more algae to grow."

Basu said strategies to tackle the problem could include adding oxygen or chemicals to the water in reservoirs to prevent the conversion of phosphorus attached to soil into dissolved phosphorus.

Vehicles moving at hypersonic speeds are bombarded with ice crystals and dust particles in the surrounding atmosphere, making the surface material vulnerable to damage such as erosion and sputtering with each tiny collision. Researchers at the University of Illinois at Urbana-Champaign studied this interaction one molecule at a time to understand the processes, then scaled up the data to make it compatible with simulations that require a larger scale.

Doctoral student Neil Mehta working with Prof. Deborah Levin looked at two different materials that are commonly used on the exterior surfaces of slender bodies --a smooth graphene and a rougher quartz. In the model, these materials were attacked by aggregates composed of argon atoms and silicon and oxygen atoms to simulate ice and dust particles hitting the two surface materials. These molecular dynamics studies taught them what stuck to the surfaces, the damage done, and the length of time it took to cause the damage--all at the size of a single angstrom, which is basically the length of an atom.

Why so small? Mehta said it's important to start by looking at "first principles" to thoroughly understand the erosive effects of ice and silica to graphene and quartz surfaces. But those who simulate fluid dynamics use lengths that are several milli-meters micrometer to cm -- so scaling up the physics of the MD models was urgently needed. The excitement about this work is that it was the first to ever do so in this application.

"Unfortunately, you can't just take the results from this very tiny angstrom level and use it in aerospace engineering reentry vehicle calculations," Mehta said. "You can't directly jump from molecular dynamics to computational fluid dynamics. It takes several more steps. Applying the rigor of kinetic Monte Carlo techniques, we took details at this very tiny scale and analyzed the dominant trends so that larger simulation techniques can use them in modeling programs that simulate the evolution of surface processes that occur in hypersonic flight, such as erosion, sputtering, pitting.

"At what rate will these processes happen and with what likelihood will these types of damages happen were the key features that no other Kinetic Monte Carlo or scale bridging has used before," he said.

According to Mehta, the work is unique because it incorporated experimental observations of gas-surface interactions and molecular dynamics simulations to create a "first principles" rule that can be applied to all of these surfaces.

"For example, ice has a tendency to form flakes, ice crystals. It creates a fractal pattern because ice likes to stick to another ice, so it's more likely that the water vapor will condense next to an ice particle that is already on the surface and create a trellis-like feature. Whereas sand just scatters. It doesn't have any preference. So one rule is that ice likes to stick to other ice.

"Similarly, for degradation, the rule on graphene is that damage is more likely to occur next to pre-existing damage," Mehta said. "There are several rules, depending on what material you're using, that you can actually study what happens from an atomic level to a micrometer landscape, then use the results to implement in computational fluid dynamics or any long, large-scale simulation," Mehta said.

One application for this work is for research on how to design thermal protection systems for slender vehicles and small satellites being at altitudes near 100 km.

A UC Davis study found that the damaged gut lining (known as leaky gut) in monkeys infected with chronic simian immunodeficiency virus (SIV), an HIV-like virus, was rapidly repaired within five hours of receiving Lactobacillus plantarum bacteria.

The study, published today in the PNAS, linked chronically inflamed leaky gut to the loss of PPARα signaling (a nuclear receptor protein responsible for regulating cell metabolism) and subsequent damage to mitochondria - the cell's power house.

The researchers found that L. plantarum activated PPARα signaling and revived mitochondrial flow, repairing the gut barrier in only five hours of exposure.

The outcome lends hope that leaky gut, a common condition among HIV patients, could be effectively treated in the future.

HIV and the damage to the gut lining

The gut, home to majority of the lymphoid tissue in the body, is an early target of HIV. The virus severely damages the immune and epithelial cells in the gut's lining. This damage leads to an inflamed and leaky gut with weakened defense system and decreased nutrient absorption.

Anti-retroviral therapy (ART) for HIV has been successful in limiting the damage to the body's immune system. Yet, it has failed to consistently or completely repair the damage to the gut and its lining.

"We wanted to map the pathways that lead to sustained damage in the gut and to identify ways to intervene and support its repair," said Katti Crakes, doctoral student in the schools of Medicine and Veterinary Medicine at UC Davis and first author on the study.

The researchers found that HIV attacks the gut's epithelial cells by targeting and draining the mitochondria.

"To reverse the damage caused by HIV and to increase the efficacy of ART, it is important to restore mitochondrial function and to rapidly repair the gut epithelium and immune defense," said Satya Dandekar, professor of microbiology and immunology at UC Davis School of Medicine and senior author.

Identifying cell signaling regulators for restoring the gut barrier

The bacteria present in the gut are known to play an important role in supporting and repairing the gut functioning. The study specifically tested the impact of L. plantarum bacteria on gut epithelial barrier of SIV infected rhesus macaques.

"We challenged the capacity of L. plantarum bacteria and their metabolites to restore the gut functions in an extremely inflamed visibly disrupted gut environment," Dandekar said.

The researchers found that L. plantarum were able to survive and remain metabolically active in inflamed gut. The bacteria repaired the gut barrier by targeting and restoring the mitochondria in the intestinal epithelial cells damaged by SIV as well as HIV. These findings provide translational insights into restoring gut immunity and function, both of which are essential for successful HIV cure efforts.

Not surprisingly, parents with substance use disorders often struggle with parenting and frequently have strained relationships with their children. Moreover, research has solidly demonstrated that the children of these parents are more likely to develop behavioral problems, antisocial behavior, aggression, mood disorders, anxiety, and later use substances themselves.

For those who treat affected families, however, the findings have left a lot of questions unanswered.

First, while parents with substance use disorders are more likely to treat their children harshly, they don’t do so all the time. What are the triggers?

Second, how can substance-dependent mothers and their medical care providers predict difficulties across challenging parenting contexts?

Greater insight into these questions is critical, given the prevalence of alcohol dependency and its harmful effects on child development. Roughly one in eight children in the US lives with a parent who struggles with a substance use disorder. Specifically, alcohol dependence among mothers of childrearing age has been steadily increasing. Research has shown that the effects of alcohol are exaggerated among women, causing reduced stress tolerance and interfering with many of the complex cognitive processes needed for sensitive and supportive parenting.

The triggers of harsh parenting

A new study by a team of University of Rochester and University of Minnesota psychologists, published in the journal Development and Psychopathology, makes considerable progress towards answering both questions.

Lead author Debrielle Jacques, a Rochester doctoral student in psychology, observed mothers and their children in two contexts: during free play and during a cleanup task. Coders then rated each of the mothers’ interactions on a nine-point scale measuring the degree of harshness. (The researchers also collected observations about the child’s temperament through another set of experiments, and assessed the mother’s alcohol dependence with the help of a widely-used diagnostic interview schedule.) The study focused on mostly ethnic minority, low-income families, following a high-risk sample of 201 moms with their two-year-old children over a one-year period, observing behaviors during nine separate visits to a research laboratory.

“Over the course of a one-year period, harsh parenting among non-alcohol dependent mothers decreased by 36 percent, while it increased by about 9 percent for alcohol-dependent mothers.”

What exactly is harsh parenting? As the researchers define it, it can include nonverbal communication, such as angry or contemptuous facial expressions and menacing or threatening body postures; emotional expression, such as irritability, lack of patience and sensitivity, sarcastic comments, and curt answers; or rejection, such as actively ignoring the child, showing contempt or disgust for the child or the child’s behavior, or denying the child’s needs.

Jacques and her co-authors—Rochester psychology professors Melissa Sturge-Apple and Patrick Davies, and Dante Cicchetti, a professor and the research director at the University of Minnesota’s Institute of Child Development, found that:

Alcohol-dependent mothers act more harshly when disciplining, but not when playing with their child.
Alcohol-dependent mothers used harsher discipline when their child is highly frustrated, but not when their child is sad or fearful.
A child’s temperament plays a direct role in how mothers react: when children express intense negative emotions such as defiance and anger, or aggressive traits, mothers are more likely to react harshly.
A mother’s alcohol dependence is a significant predictor of harsh parenting over time—well above other parenting risk factors, such as mental disorders, the mother’s age, and family income. Specifically, harsh parenting among non-alcohol-dependent mothers decreased by 36 percent over the one-year study period; however, among alcohol-dependent mothers harsh parenting increased by about 9 percent during that same time.
Mothers with greater psychological-behavioral difficulties stemming from alcohol impairment—who also have children with higher levels of negative emotions, behaviors, and characteristics—show higher levels of harsh parenting over time. Mothers with alcohol-related impairments were approximately 66 percent more likely to become harsher over time compared to mothers without alcohol-related impairments.

Sturge-Apple, who serves as Jacques’ doctoral advisor and is a Rochester vice provost and University dean of graduate education, observes that alcohol dependence “may disrupt the cognitive-emotional processes that regulate a parent’s response to a child who is behaving in a challenging or difficult manner. That’s why it can be difficult for alcohol-dependent mothers to respond to angry and demanding children with noncoercive strategies.”

Jacques points out that during the cleanup task, the mother is faced with the primary goal to get the child to listen; but often children won’t listen and instead respond in their own temperamental ways.

“Now, she also has to combat the way the child is responding to her—posing an additional demand. For moms who have a lot of alcohol-related impairments, we know that they find parenting stressful anyway, which makes this a kind of triple stresser,” says Jacques.

The team hopes their study will shed light on the unique parenting challenges faced by black and Hispanic mothers who suffer from alcohol-related issues—“a particularly vulnerable group that has been missing from the research spotlight,” notes Jacques, who identifies as Latina and whose research focuses on high-risk, ethnic-minority mothers. According to Jacques these women often come to motherhood with higher levels of underlying trauma. “These women might have experienced, even from an earlier age, higher rates of sexual abuse, emotional, or physical abuse—trauma that we may not see at these rates in white women.”

Because few studies have focused on mothers from these minority backgrounds, resources have not been tailored to their specific needs and struggles as parents, the team says. That’s why the researchers see their study as a significant first step not only in understanding when and why these mothers behave harshly, but also how to help them improve interactions with their children and ultimately become better parents.

“It’s important to look at how alcohol-dependent mothers operate in different caregiving situations. Because if you are doing a caregiving intervention you need to know which specific situations to target,” says Jacques.

NASA's Aqua satellite captured an image of newly formed Tropical Storm Sebastien, located northeast of the Leeward Islands in the Atlantic Ocean.

On Nov. 19, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA's Aqua satellite provided a visible image of Sebastien. The MODIS image showed that the overall cloud pattern of the disturbance has improved since yesterday, Nov. 18, and that the low-pressure area has become well-defined.

NOAA's National Hurricane Center or NHC noted at 11 a.m. EST (1500 UTC), the center of Tropical Storm Sebastien was located near latitude 20.1 north and longitude 58.7 west. That is about 275 miles (445 km) northeast of the Leeward Islands.

Sebastien is moving toward the north-northwest near 8 mph (13 kph). A turn to the north is expected on Wednesday followed by a turn to the northeast and an increase in forward speed Wednesday night. Maximum sustained winds are near 45 mph (75 kph) with higher gusts. Some slight strengthening is possible over the next day or so. The estimated minimum central pressure is 1008 millibars.

Sebastien is expected to become absorbed by a cold front in a couple of days.

NASA's Aqua satellite is one in a fleet of NASA satellites that provide data for hurricane research.

Hurricanes are the most powerful weather event on Earth. NASA's expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

For updated forecasts, visit: https://www.nhc.noaa.gov