Culture

LA JOLLA--(July 29, 2020) In research that aims to illuminate the causes of human developmental disorders, Salk scientists have generated 168 new maps of chemical marks on strands of DNA--called methylation--in developing mice.

The data, published July 29, 2020, in a special edition of Nature devoted to the ENCODE Project (a public research effort aimed at identifying all functional elements in the human and mouse genomes), can help narrow down regions of the human genome that play roles in diseases such as schizophrenia and Rett Syndrome. The paper's authors are also on two additional papers in the special edition.

"This is the only available data set that looks at the methylation in a developing mouse over time, tissue by tissue," says senior author and Howard Hughes Medical Institute Investigator Joseph Ecker, a professor in Salk's Genomic Analysis Laboratory. "It's going to be a valuable resource to help in narrowing down the causal tissues of human developmental diseases."

While the sequence of DNA contained in every cell of your body is virtually identical, chemical marks on those strands of DNA give the cells their unique identities. The patterns of methylation on adult brain cells, for instance, are different than those on adult liver cells. That's in part because of short stretches in the genome called enhancers. When transcription factor proteins bind to these enhancer regions, a target gene is much more likely to be expressed. When an enhancer is methylated, however, transcription factors generally can't bind and the associated gene is less likely to be activated; these methyl marks are akin to applying the hand brake after parking a car.

Researchers know that mutations in these enhancer regions--by affecting the expression levels of a corresponding gene--can cause disease. But there are hundreds of thousands of enhancers and they can be located far from the gene they help regulate. So narrowing down which enhancer mutations may play a role in a developmental disease has been a challenge.

In the new work, Ecker and collaborators used experimental technologies and computational algorithms that they previously developed to study the DNA methylation patterns of cells in samples of a dozen types of tissues from mice over eight developmental stages.

"The breadth of samples that we applied this technology to is what's really key," says first author Yupeng He, who was previously a Salk postdoctoral research fellow and is now a senior bioinformatics scientist at Guardant Health.

They discovered more than 1.8 million regions of the mouse genome that had variations in methylation based on tissue, developmental stage or both. Early in development, those changes were mostly the loss of methylation on DNA--akin to removing the brake on gene expression and allowing developmental genes to turn on. After birth, however, most sites became highly methylated again, putting the brakes on gene expression as the mouse approaches birth.

"We think that the removal of methylation makes the whole genome more open to dynamic regulation during development," says He. "After birth, genes critical for early development need to be more stably silenced because we don't want them turned on in mature tissue, so that's when methylation comes in and helps shut down the early developmental enhancers."

In the past, many researchers have studied methylation by homing in on areas of the genome near genes called CpG islands--sections of DNA that have a lot of cytosine and guanine base pairs in them, since typical methylation occurs when a methyl is added to a cytosine that's followed by a guanine. However, in the new work, He and Ecker showed that 91.5 percent of the methylation variations they found during development far away from CpG islands.

"If you only look at those CpG island regions near genes, as many people do, you'll miss a lot of the meaningful DNA changes that could be directly related to your research questions," says He.

To show the utility of their new data set, the researchers looked at genetic variations that had been linked to 27 human diseases and disorders in previous genome-wide association studies (GWAS). They found associations between some human disease mutations and tissue-specific methylation patterns in corresponding regions of the mouse genome. For instance, mutations associated with schizophrenia were more likely to be found in suspected gene control regions in the mouse genome that undergo methylation changes in an area of the brain called the forebrain during development. Such patterns could help other researchers narrow down which mutations found in a GWAS they should focus on.

au, could offer the clearest view on Earth of the stars at night, according to new research by an international team from China, Australia and the University of British Columbia (UBC). The challenge? The location is one of the coldest and most remote places on Earth.

The findings were published today in Nature.

"A telescope located at Dome A could out-perform a similar telescope located at any other astronomical site on the planet," said UBC astronomer Paul Hickson, a co-author of the study. "The combination of high altitude, low temperature, long periods of continuous darkness, and an exceptionally stable atmosphere, makes Dome A a very attractive location for optical and infrared astronomy. A telescope located there would have sharper images and could detect fainter objects."

One of the biggest challenges in Earth-based astronomy is overcoming the effect of atmospheric turbulence on telescope image quality. This turbulence makes stars twinkle, and measurement of its impact is referred to as 'seeing'. The less turbulence (the lower the seeing number) the better.

"The thinner boundary layer at Dome A makes it less challenging to locate a telescope above it, thereby giving greater access to the free atmosphere," said UBC astronomer Bin Ma, lead author on the paper.

Currently, the highest performing observatories are located in high-altitude locations along the equator (Chile and Hawai?i) and offer seeing in the range of 0.6 to 0.8 arcseconds. In general, the Antarctic has the potential for better seeing, owing to weaker turbulence in the free atmosphere, with an estimated range of 0.23 to 0.36 arcseconds at a location called Dome C.

Ma, Hickson and colleagues in China and Australia evaluated a different location, Dome A--also referred to as Dome Argus. Dome A is located near the centre of East Antartica, 1,200 kilometres inland.

The researchers estimated the location has a thinner boundary layer (the lowest part of the atmosphere, which is influenced by friction from the Earth's surface) than Dome C. Previous measurements from Dome A have been taken in the daytime, but the authors report a median night-time seeing of 0.31 arcseconds, reaching as low as 0.13 arcseconds.

The measurements from Dome A, taken at a height of eight metres, were much better than those from the same height at Dome C and comparable to those at a height of 20 metres at Dome C.

Not surprisingly, the viewing capabilities of the researchers' equipment were also hampered by frost--overcoming this issue could improve seeing by 10 to 12 per cent. But the site has promise, according to Ma.

"Our telescope observed the sky fully automatically at an unmanned station in Antarctica for seven months, with air temperature dropping to -75C at times. In and of itself, that's a technological breakthrough."

Infidelity is one of the most common reasons that heterosexual couples break up. Researchers who have studied 160 different cultures find this to be true worldwide.

However, men and women look at different types of infidelity differently.

Men usually regard physical infidelity - when the partner has sex with another person - more seriously than women do.

Women regard emotional infidelity - when the partner initiates a close relationship with another person - as more serious.

Despite experiencing the different types of infidelity differently, men and women are about equally willing to forgive their partner. And the new findings show that the degree of forgiveness is not related to the type of infidelity.

"We're surprised that the differences between the sexes weren't greater. The mechanisms underlying forgiveness are more or less identical between genders," says Professor Leif Edward Ottesen Kennair at the Norwegian University of Science and Technology's (NTNU) Department of Psychology.

He has co-authored a new article in the Journal of Relationships Research. The article addresses infidelity and the mechanisms behind forgiveness.

A research group at NTNU recruited 92 couples for the study. These couples independently completed a questionnaire related to issues described in hypothetical scenarios where the partner had been unfaithful in various ways.

One scenario describes the partner having sex with another person, but not falling in love.

In the other scenario, the partner falls in love with another person, but does not have sex.

So how willing are people to forgive their partner? It turns out that men and women both process  their partner's infidelity almost identically.

Most people, regardless of gender and the type of infidelity, think it unlikely that they would forgive their partner's infidelity.

"Whether or not the couple breaks up depends primarily on how threatening to the relationship they perceive the infidelity to be," says first author Trond Viggo Grøntvedt, a postdoctoral fellow in the Department of Psychology.

The more threatening the infidelity feels, the worse it is for the relationship.

Whether partners believe the relationship can continue also depends on how willing they are to forgive each other, especially in terms of avoiding distancing themselves from their partner.

Of course, great individual differences exist, even within each gender. People react differently to infidelity, according to their personality and the circumstances.

"A lot of people might think that couples who have a strong relationship would be better able to tolerate infidelity, but that wasn't indicated in our study," says Professor Mons Bendixen at NTNU's Department of Psychology.

Another aspect plays a role in cases of emotional infidelity, where no sex has taken place. To what extent can the unfaithful partner be blamed for what happened?

If you willingly have sex with another person, it pretty much doesn't matter whether you feel it's your fault.

"The degree of blame attributed to the partner was linked to the willingness to forgive," says Bendixen.

The relationship is at greater risk if the partner is required to bear a big part of the responsibility for ending up in an intimate relationship with someone else.

"The blame factor doesn't come into play when the partner is physically unfaithful," Grøntvedt says.

If you voluntarily have sex with someone other than your partner, it's more or less irrelevant whether you think it was mostly your fault or not. Possible forgiveness does not depend on accepting blame.

"In this paper we show that supporting Indigenous peoples' rights is in the interest of the conservation agenda," explains Dr. Álvaro Fernández-Llamazares, the first author of the study, from the University of Helsinki. "The future of a substantial proportion of the Amazon's biodiversity depends largely on coordinated action to support and strengthen Indigenous peoples' rights across the entire region."

The authors argue that the convergence of the agendas and priorities of both wilderness-centred conservationists and Indigenous peoples is more important than ever, as some of the government in the region have started to trample over commitments towards globally agreed goals on both the environment and Indigenous peoples' rights.

"There is no doubt that the Amazon is at a crossroads in its social-ecological history," adds Dr. Fernández-Llamazares. "Rollbacks on environmental protections and Indigenous Peoples rights across the entire region are opening up vast natural areas to new external pressures."

All these macroeconomic and political forces are being felt in both wilderness areas and Indigenous Peoples territories. However, disputes on whether conserving wilderness should come at the expense of Indigenous peoples rights undermine potential for collaborative conservation.

Minimal forest loss on Indigenous territories across the Amazon

The study underscored the substantial role of Indigenous territories in buffering against deforestation through advanced geospatial analyses based on available satellite data. These lands account for less than 15% of all the forest loss occurring within the Amazon's last wilderness frontiers. This is largely evidenced throughout the southern rim of the Amazon, where Indigenous territories represent the only islands of biological and cultural diversity in the larger landscape.

"The concept of wilderness has a contentious history across much of the Global South, as it is based on the assumption that humans have inherently negative impacts on nature," highlights Prof. Eduardo S. Brondizio, a researcher from Indiana University Bloomington and senior author of the study.

"Yet, the Amazon is a classic example of how long-term interactions between Indigenous peoples and forests can be linked to positive environmental outcomes. We have known for decades that a significant portion of the region's supposedly pristine forests are in fact cultural forests,"he notes. "Indigenous peoples, and also other traditional communities, show that it is possible to successfully combine forest conservation, management and agroforestry systems."

In view of this, the authors call for a more socially inclusive notion of wilderness in order to align the agendas and priorities of both wilderness-focused conservationists and Indigenous peoples against a new wave of frontier expansion.

A new study from Trinity College Dublin highlights that fitness may be a more important clinical endpoint for improvement in patients with fatty liver diseases during exercise trials, rather than weight loss. The findings have been published today (Tuesday, 28th July 2020) in the medical journal Alimentary Pharmacology and Therapeutics.

Metabolic associated fatty liver disease (MAFLD) is a condition characterised by a build up of fat in the liver. The liver is central to a suite of vital processes in the body including digestion, blood clotting and energy production.

If left untreated, MAFLD can lead to serious complications like liver fibrosis (scarring), cirrhosis, liver failure and liver cancer, as well as cardiovascular and metabolic issues. Risk factors for developing MAFLD include type 2 diabetes and obesity. The global estimated prevalence of MAFLD is 25%, making it the leading cause of chronic liver disease worldwide, and is quickly becoming the leading cause of cirrhosis and liver cancer in liver transplant candidates in the western world.

Up to now, due to the lack of approved pharmacological interventions, treatment has been a combination of prescribed weight loss and physical activity, with a weight loss target of 7-10% being the primary treatment endpoint. There is some evidence that exercise training alone without significant weight loss can reduce liver fat content (assessed using non-invasive methodologies such as transient elastography and ultrasound) in MAFLD patients. However, the independent effects of exercise alone on biopsy-measured outcomes (the gold standard for diagnosing and assessing MAFLD) have been unknown.

This new study highlights that increased fitness, the result of aerobic exercise participation, may be a more important clinical endpoint for improvement in MAFLD patients during exercise trials, rather than weight loss.

In Ireland and worldwide, MAFLD is a silent epidemic. In Ireland, there is currently no national screening programme for the disease, so the true prevalence in Ireland is unknown. However, St James's Hospital, Dublin, where the study took place, now has over 1000 patients on their own database, with the numbers growing year on year.

The Trinity study is the first to demonstrate significant improvements in biopsy-measured liver outcomes in a MAFLD cohort following an exercise-only intervention, without clinically significant weight loss. The study also demonstrates that improvements in biopsy-measured liver outcomes were significantly related to improvements in fitness levels. The study also found however, that when patients were followed up longitudinally, none of the benefits of the exercise intervention were sustained.

The study is unique in that it used repeat biopsies in MAFLD patients during an exercise-only intervention. Only two previous studies have been conducted using repeat biopsies in exercise-only trials, but these studies had significant methodological limitations. These studies used low-intensity resistance exercise and lacked exercise supervision, which may have led to non-significant changes on liver biopsy outcomes. This study is also the first to relate improvements on liver biopsies with improvements in fitness, suggesting a potential interrelationship between the two outcomes.

Dr Philip O'Gorman, Department of Physiotherapy, Trinity College said:

"The benefits of exercise training on both liver and cardiometabolic outcomes for these patients is very clear. Our findings suggest that there is an urgent need to better transition exercise into the community setting for these patients as the benefits of exercise intervention were not sustained longitudinally. This study clearly demonstrates the clinical benefit of exercise in MAFLD in as little as 12 weeks and shows the clinical benefit of improving cardiorespiratory fitness, which is increasingly being considered a 'clinical vital sign.'

Worryingly, there is little to no exercise referral systems in place within hospital departments and beyond throughout the healthcare system in Ireland. However, as our results have shown, the lack of sustainability of the benefits of exercise in MAFLD is concerning and there is an urgent unmet need to enable patients to continually engage in exercise therapy in the community setting. A systems-based approach whereby clinicians can refer patients to exercise specialists in the community is required for long-term benefits of exercise to be sustained."

Skoltech researchers and their colleagues from Aalto University have discovered that electrochemical doping with ionic liquid can significantly enhance the optical and electrical properties of transparent conductors made of single-walled carbon nanotube films. The results were published in the journal Carbon.

A single-walled carbon nanotube (SWCNT) is a seamless rolled sheet of graphene, a list of graphite that is one atom thick. Just as other new carbon allotropes, SWCNTs demonstrate unique properties which can be employed in novel electronic devices that we use in our everyday life. One of the most promising applications is transparent conductors, which can be useful in medicine, green energy, and other fields: here, SWCNT films can replace the industrial standard indium-tin oxide (ITO). They are highly conductive, flexible, stretchable and can be easy doped due to the fact that all atoms in the nanotube are located on its surface.

Doping of SWCNTs allows to significantly increase film conductivity by eliminating the Schottky barriers between the tubes with different nature and increase the concentration of charge carriers. Moreover, the doping process leads to an increase in the transmittance of the films due to supersession of optical transitions.

While adsorption doping remains one of the most promising techniques for SWCNT modification, this method lacks uniformity and reversibility. In the new study, researchers propose a new reversible method to fine-tune the Fermi level of SWCNTs, dramatically increasing the conductivity while the optical transitions are suppressed. For this, they used electrochemical doping with an ionic liquid with a large potential window, which facilitates a high level of doping.

"We placed the SWCNT thin film into electrochemical cell and used standard three electrode scheme to apply potential to the nanotubes. With applying the negative/positive potential to the SWCNT film, an electrical double layer is formed at the SWCNT/ionic liquid interface. The latter acts as parallel plate capacitor causing positive/negative charge injection to SWCNT film surface and consequently the Fermi level shift," explains Daria Kopylova, the first author of the study and senior research scientist at Skoltech.

The scientists were able to show that their electrochemical method can help achieve extremely high doping levels, comparable to the best results for doped SWCNTs films recently published in the field.

"The process is fully reversible so that it can be used to fine-tune the electronic structure of the single-walled carbon nanotubes in real time. Operating with the gate voltage, you can drive both optical transmittance and electrical conductivity of the films. The results open new avenues for future electronics, electrochromic devices, and ionotronics," says Albert Nasibulin, head of Laboratory of Nanomaterials at the Skoltech Center for Photonics and Quantum Materials.

Coccidiosis is a kind of intestinal illness that affects different groups of animals. It inhibits the absorption of nutrients and growth so that, at times, the animal dies, thus producing financial losses in the livestock industry. In order to fight this disease, antibiotics like coccidiostats are prescribed, which are effective drugs in treating the illness but that also can cause cardiovascular diseases in human beings when concentrations are high in food products from animal sources.

The Supramolecular Analytical Chemistry reseach group at the University of Cordoba developed a new method that allows for extracting and determining these substances in food from animal sources. According to the lead researcher on the study, Soledad González, the procedure is able to simultaneously extract the whole group of ionophore antibiotics (as in, those from a natural source) from all the animal source foods that are legislated in the European Union, something "done for the first time in this research project".

Specifically, the method uses supramolecular, nontoxic solvents known as SUPRAS, which have a high capacity to improve selectivity and performance of the extractions, thus lowering production costs. As pointed out by researcher Soledad González, these kinds of solvents make it possible to simultaneously extract antibiotic residue and clean the sample in a single step. What is more, "this is a low-cost, environmentally friendly method, since it uses a lower volume of organic solvent compared to other widely and routinely used techniques in laboratories", she adds.

After applying the new methodology on different products such as eggs, milk and meat (liver, kidney, muscle and fat), the detection limits that were reached were verified to be much lower than the legal limit, proving that this procedure could be applicable in food quality control laboratories. Besides, the new method has been validated following European decision 2002/657/EC, regulating the presence of residues in animal source products, so it could be incorporated into routine controls at laboratories. Researchers Ana María Ballesteros, Soledad Rubio and Diego García-Gómez also participated in this study, with García-Gómez being from the University of Salamanca.

Buzzing by bees during flower pollination is significantly more powerful than that used for defence or flight, according to a new study from experts at the University of Stirling.

The research found that flower buzzing produced forces of more than 50G - five times that experienced by fighter jet pilots - and provides an important insight into the pollination process.

Dr David Pritchard, of the University's Faculty of Natural Sciences, led the study and believes the findings suggest that bees use specific types of buzzing vibrations for certain tasks.

Dr Pritchard said: "We know that bees use their distinctive buzzing vibrations for lots of different tasks and, for this study, we wanted to understand whether buzzes differed by task - or if variations in buzzing were caused by drag on the wings.

"We found that flower buzzes were much more powerful than those used for defence or flight - suggesting that, rather than being due to drag, bees might have evolved different types of buzzes for different tasks.

"Buzz-pollinated flowers represent some of our most important economic crops - such as potatoes, tomatoes, aubergines and blueberries - and understanding how bees buzz these flowers also provides an important insight into how these flowers coevolved with bees. This is important because it helps us better understand what these flowers need in order to be pollinated."

Previous studies have identified variations between flight buzzing and defensive buzzing. During flight buzzing, bees' wings flap, however, during defensive buzzing they do not - therefore, it was not clear whether buzzing variations were caused by flapping wings, or not.

To further understand the issue, Dr Pritchard - working with Stirling colleague Dr Mario Vallejo-Marin - looked at flower buzzing, during which the bees' wings do not flap. Flower buzzing occurs when bees vibrate flowers to shake pollen onto their bodies.

During the experiment, bees foraged on a buzz-pollinated flower, performed a tethered flight, or were encouraged to perform a defensive buzz through a gentle stroke of their body. The team used a laser to scan a reflective tag on the bees' bodies to measure the speed of movement 10,000 times per second, with the data analysed by computer.

"We wanted to understand whether defensive buzzing and flower buzzing were similar - and if buzzing variation could be attributed to wing flapping or if bees adapt depending on the task in hand," Dr Pritchard said. "We found that flower buzzes were much more powerful than buzzes used for defence or for flight - suggesting that, rather than being due to drag on the wings, bees might have evolved different types of buzzes for different tasks."

He added: "Flower buzzing is important to understand because not all bees can buzz flowers. For example, we still do not understand why honeybees do not buzz flowers. By better understanding how flower buzzes appear and differ from the other vibrations bees produce, it may shed light on the reasons why some bees buzz flowers and some do not."

A study on marine biodiversity has identified seventy-three species of sea slugs in the coasts of Barcelona, an anthropized environment due to the urban metropolis.

In this group of gastropod molluscs, the most abundant in the urban coasts are sea hares, according to the article coordinated by the tenure university lecturer Manuel Ballesteros, from the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona.

This is one of the few ecological studies on these species in port cities in the Mediterranean and it is published in the Gazette of the Catalan Institution of Natural History (BICHN, 2020), an entity from the Institute for Catalan Studies (IEC). Other coauthors of the study are the experts Àlex Parera, from the Faculty of Biology of the UB; Miquel Pontes, from the VIMAR Study Group, and Xavier Salvador, from the Catalan Opisthobranchs Research Group (GROC).

City catalogue of opisthobranchs in the Barcelona coasts

The marine invertebrates traditionally known as opisthobranchs -nowadays heterobranchia- gather a wide group of gastheropod molluscs -nudibranchs, sea hares, sacoglossa, sea butterflies, etc. - with polyphyletic origins. These are abundant in marine areas where it is easy to find their food -usually an only species of animal or algae- and show a high biodiversity in marine ecosystems with varied habitats (rocks, sandy floors, etc.).

The degradation or damage of marine habitats is a global threat for the biodiversity of heterobranchia. The highly anthropized environments, factors such as human pressure on the natural habitat and the eutrophication of the environment by urban waste usually favour the disproportionate development of a few species. In habitats with little human pressure, the natural balance turns into a higher biodiversity and the stability of biological communities over time.

Regarding the coasts of Barcelona, "this marine habitat has been transformed by human activities, construction of walls, cement dikes, reefs, harbours and sports marinas, etc. that give new survival opportunities to animal species that couldn't otherwise survive in their original place (like their predators). The human pressure affects negatively many fragile species -gorgonians, bryozoans, sponges-, which are the foo source of many organisms, and this conditions their presence in the marine environment", notes the lecturer Manuel Ballesteros, from the Department of Evolutionary Biology, Ecology and Environmental Sciences of the UB.

"In some way -he continues- we could say these sea slug species have been selected by our actions on the marine environment".

From sandy floors to harbour constructions

In general, many small-sized species and with nocturnal habitats have been found. These are associated with the fauna of habitats in rocks and reeds in the coasts of Barcelona. The most abundant ones are anaspidea -known as sea hares, they feed from algae- and cephalaspidea, which usually feed from organisms that live in the mud or sand. In the case of nudibranchs, which are mainly carnivorous, their presence in the Barcelona coast is very little and there have been only a few findings.

Many species of heterobranchia can be found in colonies of hydrozoans, gorgonians or marine sponges, that is, in places where there is a certain amount of phytoplankton and zooplankton for the nutrition of these organisms. In some cases, too much organic matter in the marine environment can cause bloom in algae and bryozoans, which is detrimental to the conservation of the biodiversity of molluscs. However, anaspidean and sacoglossa populations benefit from the growth of algae in shallow waters, conditions given in many harbour structures.

Experts identified seventy-three different species of sea slugs in the urban coast, although the ecological state of the urban waters is not good, specially in the mouths of the Besòs river and the semi-closed littoral areas like in Forum. "However, it is surprising to find many species in such an anthropized environment like beaches and the inside of the harbour and marinas of Barcelona, in a coastal line near eleven kilometres, from the Besos River to the Llobregat River", notes Miquel Pontes.

"But we should confirm -he continues- whether these results come from a lack of previous knowledge on the presence of these gastropods or whether it is a response to an efficient colonization process of the substrates that have been artificially created in the Barcelona coasts over the last decades".

According to the experts, the configuration of found species is different than those in other places which are better conserved, such as Medes Islands, where the scientific team has identified up to a hundred and eight different species since 2010.

"While in Barcelona we see a higher amount of specimens that eat algae, in the Medes islands we find mainly species that feed from sponges, cnidarian and bryozoans, the presence of which in Barcelona is merely anecdotic", note Ballesteros and Pontes, co-authors with Enric Madrenas of the book Els nudibranquis del mar català (El Brau, 2019), the first field guide dedicated to more than 150 species of nudibranchs identified so far in the marine ecosystems in Catalonia.

A more and more tropical Mediterranean

Climate change is favouring the presence of exotic marine species in the Mediterranean coming from the Red Sea -through the Suez channel- or the Atlantic after having crossed the Strait of Gibraltar. In this situation, the study identifies the presence of allochthonous species -Bursatella leachii and Polycerella emertoni- in the urban marine ecosystem of Barcelona, but its ecological impact seems to be null.

"The sea hare Bursatella leachii, with a notable size and high reproductive skills, could be a problem in case there is a lot of food. However, this is not the case ye, so this is rather an interesting finding instead of a problematic one", note the authors. According to them, this species feeds from diatoms, and does not compete against other autochthonous species of sea hares such as Aplysia punctate and Aplysia depilans, which feed from different algae species.

Another exotic species, Polycerella emertoni, is extremely small-sized and it is related to the seasonal bryozoan Amathia verticillate, an organism that usually moves the native fauna during summer, but it disappears when waters are cooler.

"In general, the Mediterranean is believed to go towards tropical conditions. If this process continues, we will have to get used to see more and more exotic species", warn Manuel Ballesteros and Miquel Pontes.

Meteorites give us insight into the early development of the solar system. Using the SAPHiR instrument at the Research Neutron Source Heinz Maier-Leibnitz (FRM II) at the Technical University of Munich (TUM), a scientific team has for the first time simulated the formation of a class of stony-iron meteorites, so-called pallasites, on a purely experimental basis.

"Pallasites are the optically most beautiful and unusual meteorites," says Dr. Nicolas Walte, the first author of the study, in an enthusiastic voice. They belong to the group of stony-iron meteorites and comprise green olivine crystals embedded in nickel and iron. Despite decades of research, their exact origins remained shrouded in mystery.

To solve this puzzle, Dr. Nicolas Walte, an instrument scientist at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, together with colleagues from the Bavarian Geoinstitute at the University of Bayreuth and the Royal Holloway University of London, investigated the pallasite formation process. In a first, they succeeded in experimentally reproducing the structures of all types of pallasites.

Deployment of the SAPHiR instrument

For its experiments, the team used the SAPHiR multi-anvil press which was set up under the lead of Prof. Hans Keppler of the Bavarian Geoinstitute at the MLZ and the similar MAVO press in Bayreuth. Although neutrons from the FRM II have not yet been fed into SAPHiR, experiments under high pressures and at high temperatures can already be performed.

"With a press force of 2400 tons, SAPHiR can exert a pressure of 15 gigapascals (GPa) on samples at over 2000 °C," explains Walte. "That is double the pressures needed to convert graphite into diamond." To simulate the collision of two celestial bodies, the research team required a pressure of merely 1 GPa at 1300 °C.

How are pallasites formed?

Until recently, pallasites were believed to form at the boundary between the metallic core and the rocky mantle of asteroids. According to an alternative scenario, pallasites form closer to the surface after the collision with another celestial body. During the impact molten iron from the core of the impactor mingles with the olivine-rich mantle of the parent body.

The experiments carried out have now confirmed this impact hypothesis. Another prerequisite for the formation of pallasites is that the iron core and rocky mantle of the asteroid have partially separated beforehand.

All this happened shortly after their formation about 4.5 billion years ago. During this phase, the asteroids heated up until the denser metallic components melted and sank to the center of the celestial bodies.

The key finding of the study is that both processes - the partial separation of core and mantle, and the subsequent impact of another celestial body - are required for pallasites to form.

Insights into the origins of the solar system

"Generally, meteorites are the oldest directly accessible constituents of our solar system. The age of the solar system and its early history are inferred primarily from the investigation of meteorites," explains Walte.

"Like many asteroids, the Earth and moon are stratified into multiple layers, consisting of core, mantle and crust," says Nicolas Walte. "In this way, complex worlds were created through the agglomeration of cosmic debris. In the case of the Earth, this ultimately laid the foundations for the emergence of life."

The high-pressure experiments and the comparison with pallasites highlight significant processes that occurred in the early solar system. The team's experiments provide new insights into the collision and material mixing of two celestial bodies and the subsequent rapid cooling down together. This will be investigated in more detail in future studies.

Introducing the newly designed 'meta-grid' of nanoparticles into the epoxy casing of light-emitting diodes (LEDs) offers a substantial improvement of their light output, besides increasing lifetime, according to the scientists who invented it. A 'meta-grid' is a specially designed, optimized two-dimensional array of metallic nanoparticles, which needs to be placed at a specific location within the epoxy casing of the LEDs.

LEDs are overwhelmingly employed in the modern world. From traffic lights to backlighting for electronic displays, smartphones, large outdoor screens, and general decorative lightings and to sensing, water purification, and decontamination of infected surfaces -- LEDs are all around us! Increasing LED light output would reduce energy needs, contributing to curbing global warming and climate change.

Over the years, the task of producing greater light output for the given input, was central for LEDs. The mainstream of research in this direction was in exploring new materials for LED chip encapsulation, mainly by using either higher refractive index glasses or nanoparticle-loaded-epoxy or epoxy materials incorporated with filler powders or engineered epoxy resins, to name a few. However, with these techniques either the LED chips become bulkier or their fabrication becomes more difficult and less economical for mass production.

In a new paper published in Light Science & Application, a team of scientists -- Dr. Debabrata Sikdar, from Indian Institute of Technology Guwahati, Department of Electronics and Electrical Engineering, along with Prof. Sir John B. Pendry and Prof. Alexei Kornyshev from Imperial College London -- reported an alternative route for improving light extraction from LEDs. It proposes increasing transmission of the light generated inside the LED chip across the LED-chip/encapsulant interface by reducing the Fresnel reflection loss at the chip/encapsulant interface within a fixed photon escape cone, while prescribing minimal changes to the manufacturing process.

The enhancement in light transmission is based on destructive interference between light reflected from the chip/epoxy interface and light reflected by the 'meta-grid'. Reducing reflection from the chip/epoxy interface can also increase the lifetime of the LED chip by eliminating heating of the chip from unwanted reflections within the chip.

These scientists summarize the operational principle and merits of their 'meta-grid' scheme for LED light enhancement below:

"A significant enhancement in light extraction from LEDs can be achieved by boosting the transmission across LED-chip/encapsulant interface, by introducing a monolayer of plasmonic nanoparticles (much smaller than the wavelength of the emitted light) on top of the LED chip which can reduce the Fresnel reflection loss at the chip/encapsulant interface, through enhanced transmission originating from the Fabry-Perot effect. A similar effect is also applicable for enhancing the trapping of light in solar cells", they said.
"Our scheme can be deployed by itself or in combination with other schemes available for increasing the LED efficiency by reducing critical angle losses. The entire original theoretical framework needed for the invention has been developed in-house and is rigorously tested against standard commercial simulation tools. We plan to fabricate a prototype device within one year and corroborate our theoretical predictions with experiments."
"Our theoretical model allows determination of the optimal conditions for the structure and properties of the nanoparticle 'meta-grid' layer: viz. the material and composition of nanoparticles, their sizes and average interparticle spacing, and the distance from the surface of the LED chip -- that could provide the maximum enhancement in light extraction from the LED chip into the encapsulating casing, over any emission spectral range of LEDs", they added.

Debabrata Sikdar further commented: "with continuous advancement in nanofabrication technology, it is becoming less difficult to fabricate the nanoparticles which are mostly monodisperse and have a very narrow spread. Still, there could always be some randomness in particle size and/or position, flatness of grid, and variation in refractive index due to fabrication error or material defects, which are unavoidable. Effects from most of these inaccuracies can be roughly estimated from our tolerance study and it has shown the robustness of the mechanism of enhanced light extraction".
"There could be different engineering solutions for the meta-grids in the LED-chips. One of them would be to use drying-mediated self-assembly of nanoparticles, e.g. made of silver or alternative less-lossy plasmonic materials capped with appropriate ligands, to form free-standing the Sikdar-Premaratne-Cheng 'plasmene' sheets. Those nanoparticle monolayer sheets could be made stretchable for precise tuning of the interparticle separation and could be stamped on the LED chip before the encapsulating casing is fabricated. The distance of the 'meta-grid' from the LED chip surface can be controlled via the thickness of the plasmene's substrate", Alexei Kornyshev further added.

The authors claimed: "In this invention, we have demonstrated the effect of the 'meta-grid' for the standard commercial LEDs, based on group III-V materials. But the proposed concept of enhancing light transmission from an emissive layer to its encapsulant casing can be extended to other types of light emitting devices containing emissive-layer/encapsulant interface. Generally, our idea of using the nanoparticle 'meta-grid' for enhanced light extraction could potentially cater to a wider range of optical gadgets, not just semiconductor LEDs".

"The simplicity of the proposed scheme and the clear physics underpinning it should make it robust and, hopefully, easily adaptable to the existing LED manufacturing process. It is obvious that with larger light extraction efficiency, LEDs will provide greater energy savings as well as longer lifetimes of the devices. This will definitely have a global impact on the versatile LED based applications and their multi-billion-dollar market worldwide", Sir John B. Pendry forecasted.

Women compose half of the entering classes of medical students, yet they are underrepresented in many of the largest surgical specialties. While some efforts are underway to recruit more women into surgical specialties, little information has been available on the rate at which the gender gap is closing. A new study led by investigators from Brigham and Women's Hospital analyzed national data available through the National Graduate Medical Education Census to determine how rates of women in surgical specialties have changed over the last 11 years and use that to project how they might change in the future. In JAMA Surgery, the team reports that, among the largest resident specialties in the U.S., little progress has been made, with most of the largest residencies demonstrating a less than 1 percent increase in women trainees per year. For many specialties, including neurosurgery and orthopaedic surgery, it will take decades to reach equal female representation if progress continues at the current pace.

"This paper shows that not all fields are created equal," said co-senior author Erika Rangel, MD, MS, a surgeon and researcher in the Division of Trauma, Burn and Surgical Critical Care. "Some fields are reaching parity or have surpassed it, but many are lagging behind."

The research team analyzed publicly available, deidentified, aggregate data from 2007 to 2018 and looked across 20 specialties with the most residents. Of the 20 programs, women were underrepresented in 13. Specialties with the lowest representation included otolaryngology, plastic surgery, urology, orthopaedic surgery and neurosurgery. The researchers then estimated how long it would take to reach gender parity at the current rate of change. They found that for orthopaedic surgery, for instance, it would require more than 100 years for female residents to be equitably represented in the specialty.

"Using the rate of change that we saw in those specialties, we did further analyses to create projections to see how long it would take the specialties with the least representation to reach levels of female representation seen among all residents overall and then that of the U.S. population," said corresponding author Christopher L. Bennett, MD, MA, a former resident in the Brigham and Women's/Massachusetts General Hospital Harvard Affiliated Emergency Medicine Residency.

The authors describe several strategies that could help to improve female student recruitment to specialties. These include recognizing and rewarding mentorship; early outreach to medical students; and implicit bias training.

"At the current pace, gender parity among many surgical specialties is still decades away," the authors write. "These data call for concerted efforts to increase the pipeline for female surgical residents."

The possibility of achieving room temperature superconductivity took a tiny step forward with a recent discovery by a team of Penn State physicists and materials scientists.

The surprising discovery involved layering a two-dimensional material called molybdenum sulfide with another material called molybdenum carbide. Molybdenum carbide is a known superconductor -- electrons can flow through the material without any resistance. Even the best of metals, such as silver or copper, lose energy through heat. This loss makes long-distance transmission of electricity more costly.

"Superconductivity occurs at very low temperatures, close to absolute zero or 0 Kelvin," said Mauricio Terrones, corresponding author on a paper in Proceedings of the National Academy of Sciences published this week. "The alpha phase of Moly carbide is superconducting at 4 Kelvin."

When layering metastable phases of molybdenum carbide with molybdenum sulfide, superconductivity occurs at 6 Kelvin, a 50% increase. Although this is not remarkable in itself -- other materials have been shown to be superconductive at temperatures as high as 150 Kelvin -- it was still an unexpected phenomenon that portends a new method to increase superconductivity at higher temperatures in other superconducting materials.

The team used modeling techniques to understand how the effect occurred experimentally.

"Calculations using quantum mechanics as implemented within density functional theory assisted in the interpretation of experimental measurements to determine the structure of the buried molybdenum carbide/molybdenum sulfide interfaces," said Susan Sinnott, professor of materials science and engineering and head of the department. "This work is a nice example of the way in which materials synthesis, characterization and modeling can come together to advance the discovery of new material systems with unique properties."

According to Terrones, "It's a fundamental discovery, but not one anyone believed would work. We are observing a phenomenon that to the best of our knowledge has never been observed before."

The team will continue experimenting with superconductive materials with the goal of someday finding materials combinations that can carry energy through the grid with zero resistance.

Air conditioning and other space cooling methods account for about 10% of all electricity consumption in the U.S., according to the U.S. Energy Information Administration. Now, researchers reporting in ACS Applied Materials & Interfaces have developed a material that cools the wearer without using any electricity. The fabric transfers heat, allows moisture to evaporate from the skin and repels water. Watch a video about the new fabric here.

Cooling off a person's body is much more efficient than cooling an entire room or building. Various clothing and textiles have been designed to do just that, but most have disadvantages, such as poor cooling capacity; large electricity consumption; complex, time-consuming manufacturing; and/or high cost. Yang Si, Bin Ding and colleagues wanted to develop a personal cooling fabric that could efficiently transfer heat away from the body, while also being breathable, water repellent and easy to make.

The researchers made the new material by electrospinning a polymer (polyurethane), a water-repelling version of the polymer (fluorinated polyurethane) and a thermally conductive filler (boron nitride nanosheets) into nanofibrous membranes. These membranes repelled water from the outside, but they had large enough pores to allow sweat to evaporate from the skin and air to circulate. The boron nitride nanosheets coated the polymer nanofibers, forming a network that conducted heat from an inside source to the outside air. In tests, the thermal conductivity was higher than that of many other conventional or high-tech fabrics. The membrane could be useful not only for personal cooling, but also for solar energy collection, seawater desalination and thermal management of electronic devices, the researchers say.

In a pilot study of people living with HIV or high levels of cholesterol, Johns Hopkins Medicine researchers found that a six-week course of a cholesterol-lowering medication improved the function of the coronary arteries that provide oxygen to the heart.

The drug used in the study, a PCSK9 inhibitor, lowers the activity of PCSK9, a protein involved in cholesterol metabolism. These levels are higher in people with HIV and in those with high cholesterol.

In a pilot study of people living with HIV or high levels of cholesterol, Johns Hopkins Medicine researchers found that a six-week course of a cholesterol-lowering medication improved the function of the coronary arteries that provide oxygen to the heart.

The drug used in the study, a PCSK9 inhibitor, lowers the activity of PCSK9, a protein involved in cholesterol metabolism. These levels are higher in people with HIV and in those with high cholesterol. Currently, people with HIV receive antiretroviral medications and rarely die from the virus itself. However, the same people have an increased risk of cardiovascular disease as a result of chronic inflammation due to the virus, and they are significantly more likely to die from cardiovascular disease than the general population.

In a study published July 17 in the Journal of the American Heart Association, the Johns Hopkins researchers suggest there may be a way to limit cardiovascular disease risk in those living with HIV and other cardiovascular risk factors, such as high cholesterol, by improving the function of blood vessels.

"We hypothesized that PCSK9 mediates an inflammatory response that impairs vascular function in addition to its effects on cholesterol metabolism, and we tested this idea with the protein's inhibitor to learn whether it could help people who have impaired blood vessel function," says lead author of the study, Thorsten M. Leucker, M.D., Ph.D., assistant professor of medicine at the Johns Hopkins University School of Medicine. "We were surprised that this worked so well, but also heartened that there may be a way we can improve blood vessel function in those with increased inflammation."

For the study, 19 people with HIV and 11 people with high blood lipids but no HIV were given the drug evolocumab, a PCSK9 inhibitor, for six weeks. At the start of the study and following the course of treatment, the team used cardiac magnetic resonance imaging (MRI) to measure the area of, and blood flow in, the right coronary artery at rest and during a hand exercise, which normally results in relaxation of the blood vessels. When healthy people perform the test, the coronary artery responds to the exercise and its area increases, enabling more blood to flow through. In people with impaired blood vessel function, such as those with HIV or high cholesterol, the artery doesn't get larger or may even constrict. Therefore, blood flow remains the same or decreases in those with impaired blood vessel function.

After the six-week treatment with the PCSK9 inhibitor, the participants living with HIV had an average 7.9% increase in coronary artery area and a 10.1% increase in blood flow during the hand grip exercise when compared to the resting value. These changes were significantly greater than the changes from rest to hand grip exercise during the baseline pre-treatment visit. Participants with high blood lipids also had improvements in coronary artery area and an increase in blood flow after six weeks of treatment.

The researchers say future studies will need to include more patients and study them over a longer time.