Tech

New technology developed at UCL is, for the first time, enabling cancer scientists to analyse the individual behaviour of millions of different cells living inside lab-grown tumours - a breakthrough which could lead to new personalised cancer treatments.

The research, published in Nature Methods, provides new insight into how mutated cancer cells "mimic the growth signals" normally expressed by healthy cells - which allows cancer cells to grow unchecked.

Corresponding author, Dr Chris Tape (UCL Cancer Institute), said: "Our new technology allows us to simultaneously measure the behaviour of cancer cells, healthy cells, and immune cells from mini-tumours.

"This new technique revealed that mutations in cancer cells mimic the growth signals normally provided by cells in the healthy tissue microenvironment.

"In healthy tissues, signals from the environment are tightly controlled so the tissue doesn't grow too fast. Unfortunately in cancer, mutations that mimic microenvironment signals are constantly switched on - allowing the cancer to grow unchecked.

"The new technology developed at UCL enabled scientists to observe this phenomenon in minute detail."

Globally, researchers can now study cancer using mini-tumours, known as 'organoids', which are grown by embedding cancer stem cells in collagen in the lab.

The 3D mini-tumours contain lots of different cells and more accurately represent a patient's cancer, compared to more traditional research, which looks at a collection of identical cells grown in 2D. This development means cancer can be studied in more detail than ever before.

However, to this point, most methods used to study mini-tumours have involved grinding up all the cells and analysing it as a mixture. This limits scientists' ability to assess how individual cells behave or how tumours collaborate with other healthy and immune cells known to influence cancer outcomes.

To overcome this, researchers at UCL Cancer Institute, have developed a new mass spectrometry platform to measure communication signals in millions of single cells from bowel cancer mini-tumours.

Specifically, researchers at UCL have developed a new technique to prepare cells for analysis on a mass spectrometer. At the subcellular level, heavy metal-tagged antibodies are attached to individual proteins (known as PTMs): these PTMs are found within all the different cell types (stem, immune, etc).

The different weight of each heavy metal allows the mass spectrometer to differentiate the different proteins and analyse their behaviours and signalling activity within and between the different cell types. More than 40 types of PTM were tagged in this process, enabling researchers to build detailed 'circuits' that describe how the cancer cells are working.

This technological breakthrough means that, for the first time, scientists can now study how cancer cells interact with any cell type using mini-tumour models.

Moving forward, UCL scientists plan to use this technology to study how tumours from individual patients can uniquely communicate with healthy cells and the immune system.

"By understanding how mini-tumours function at the single-cell level, this new technology will enable researchers to identify new ways to treat an individual's cancer," said Dr Tape.

"We expect that in the future an individual patient will have mini-tumours grown as 'living biopsies' alongside their clinical treatment.

"We will be able to test drugs on the mini-tumours and use that to inform how the patient's individual tumour should be treated.

"Unlike old approaches, our new method can also be used to study immunotherapies - not just chemotherapies - because it can measure lots of different cell types at once. Old methods could really only look at one cell type at a time."

Over half of our genomes are made of repeating elements within DNA. In rare cases, these repeats can become unstable and grow in size. These repeat "expansions" cause neurodegenerative diseases such as ALS and dementia as well as learning disorders and autism in Fragile X syndrome.

Research to date has focused on how these expanded repeats cause disease, but little attention has been given to the repeats themselves and whether they might have normal functions in genes.

By focusing on the biology of healthy nerve cells, a Michigan Medicine team found that repeats in the gene that causes Fragile X Syndrome normally regulate how and when proteins are made in neurons. This process may be important for learning and memory in these nerve cells and potentially in people.

"The repeats function like a switch, slowing down protein production and then quickly turning things back on," explains principal investigator Peter Todd, M.D., Ph.D., associate professor of neurology at Michigan Medicine.

This study first used rodents and then created human neurons from patient stem cells. The scientists found that the repeat and its translation in the beginning of the Fragile X gene slow down production of the Fragile X protein, which is important in learning and memory. However, when neurons are stimulated, this repeat translation goes away and the Fragile X protein levels increase at synapses (the connections between nerve cells), suggesting that the repeat and its translation regulate this local protein production.

Armed with this discovery about how the repeat functions normally, the team worked with Ionis Pharmaceuticals to develop an antisense oligonucleotide (ASO), a short strand of modified DNA that can specifically target the transcripts of a defective gene to correct an abnormality. Ionis' ASOs are designed to bind precisely with RNA, halting the process of creating a disease-causing protein which could block translation of expanded Fragile X repeats that are toxic to neurons and cause human disease.

This ASO has produced two remarkable results. First, it decreased the toxicity that these repeats caused in rodent and human neurons. Second, this blockade of repeat translation triggered a big increase in the Fragile X protein, whose loss causes Fragile X syndrome. "The results suggest that we have simultaneously corrected two of the big problems that happen in Fragile X-associated disorders," Todd says.

This research offers a novel pathway forward to treatments in this class of neurological diseases.

"To develop a new treatment strategy, we really needed to understand the native biology of how these repeats work and why they are there in the first place," says Todd. "The study was done in dishes, and so there is still a long way before it can be tried in patients, but advancing our understanding of normal nerve cell biology is a crucial step to find cures."

NEW YORK, NY (Feb. 17, 2020)--Women who sleep poorly tend to overeat and consume a lower-quality diet, according to a new study from researchers at Columbia University Irving Medical Center. The findings provide new insight into how poor sleep quality can increase the risk of heart disease and obesity and points to possible interventions for improving women's heart health.

Previous studies have shown that people who get less sleep are more likely to develop obesity, type 2 diabetes, and heart disease--and that the relationship may be partially explained by diet. But these studies were narrowly focused on specific foods or nutrients (such as fish, sweets, or saturated fat) or only measured sleep duration, not sleep quality.

The new study was designed to get a more comprehensive picture in women by examining associations between overall diet quality and multiple aspects of sleep quality.

"Women are particularly prone to sleep disturbances across the life span, because they often shoulder the responsibilities of caring for children and family and, later, because of menopausal hormones," says Brooke Aggarwal, EdD, assistant professor of medical sciences at Columbia University Vagelos College of Physicians and Surgeons and senior author of the study.

The study of nearly 500 women was published online today in the Journal of the American Heart Association.

The researchers analyzed the sleep and eating habits of an ethnically diverse group of 495 women, ages 20 to 76. The study looked at sleep quality, the time it took to fall asleep, and insomnia. The women also reported on the types and amounts of foods they typically eat throughout the year, allowing researchers to measure their typical dietary patterns.

Similar to previous studies of sleep and diet, the study found that those with worse overall sleep quality consumed more of the added sugars associated with obesity and diabetes.

Women who took longer to fall asleep had higher caloric intake and ate more food by weight.

And women with more severe insomnia symptoms consumed more food by weight and fewer unsaturated fats than women with milder insomnia.

"Our interpretation is that women with poor-quality sleep could be overeating during subsequent meals and making more unhealthy food choices," says Aggarwal.

The question remains: How might poor sleep contribute to poor eating?

"Poor sleep quality may lead to excessive food and calorie intake by stimulating hunger signals or suppressing signals of fullness," says Faris Zuraikat, PhD, postdoctoral fellow at Columbia University Vagelos College of Physicians and Surgeons and lead author of the study. "Fullness is largely affected by the weight or volume of food consumed, and it could be that women with insomnia consume a greater amount of food in an effort to feel full.

"However, it's also possible that poor diet has a negative impact on women's sleep quality," adds Zuraikat. "Eating more could also cause gastrointestinal discomfort, for instance, making it harder to fall asleep or remain asleep."

"Given that poor diet and overeating may lead to obesity--a well-established risk factor for heart disease--future studies should test whether therapies that improve sleep quality can promote cardiometabolic health in women," says Aggarwal.

ANN ARBOR, Mich. -- Parents from lower-income families are less likely to describe their home tap water as safe, say their water has been tested or feel confident in the quality of drinking fountain water at their child's school compared with higher income peers, a new national poll suggests.

Two-thirds of parents from households earning over $100,000 report that both home tap water and school drinking fountains are safe for their child to drink, compared to only half of those earning under $50,000 per year, according to the C.S. Mott Children's Hospital National Poll on Children's Health at the University of Michigan.

The nationally-representative report is based on responses from 1,940 parents who had at least one child age 2-18 years.

"Water plays a vital role in children's health and development, Unfortunately, not all U.S. children have access to safe drinking water," says Mott Poll co-director Sarah Clark, M.P.H.

"Only three quarters of parents polled said their home tap water is safe to drink, with substantial differences by household income. Disparities in access to safe drinking water for children is a significant public health issue that warrants attention."

Overall, three in four parents say their home tap water is safe for their child to drink, but another 13% say their tap water is not safe and 11% are unsure. This feedback was consistent regardless of whether the home water source was a city water system, a rural water system or well water.

Sixteen percent of parents say they would know if their water is unsafe by its taste and smell. This is incorrect, says Clark, noting that some contaminants, such as lead, have no taste or color or odor.

Parents may also judge water discolored by iron as unsafe, when this is an aesthetic issue rather than a sign of unsafe water.

"There is no substitute for testing water for safety," Clark says.

One third of parents also believe the city or county would notify them if there was a problem with their home water supply.

"Parents may not know how their city or county communicates the results of water testing," Clark says. "Rather than assume, parents should seek out water safety information through their local government website or their community's water treatment plant."

Higher-income parents were substantially more likely than those from lower-income households to say their home tap water has been tested and is safe (80% versus 62%.) Clark points to several potential factors, including that lower-priced housing may have old water lines and plumbing, and because poorer communities may have limited funding for water system upgrades.

State and federal regulations establish specific requirements for water testing, but in many cases, parents may not have thought to look for this information, Clark says. Even when parents seek out information about water safety, parents may not know where test results are posted or may not understand the technical language used in water testing reports.

Clark also notes that testing of the public water supply tests might not detect contamination that occurs within the home, such as from lead pipes, so some parents choose to do additional testing. Families relying on residential well water also should do additional testing, she says.

A common question for parents is also whether they need a home water treatment system. Clark says parents should think carefully about their family's needs and the functionality and effectiveness of the water treatment systems under consideration.

In homes where the water has tested as unsafe, a filter attached to the faucet may be sufficient to remove a contaminant like lead, she says. In cases where home tap water meets water quality standards, parents may use a water filter to improve taste.

However, some home treatment systems remove elements from water that actually improve public health and safety.

"Parents don't want to make a decision that offers little benefit, and the possibility of reduced health and safety," Clark says.

Water safety has been in the spotlight over recent years after news of the Flint water crisis in Flint, Mich. that started in 2014 and exposed residents, including children, to lead in the water.

Since then, reports have found that children in other communities may also be exposed to lead in drinking water from lead pipes, faucets, and plumbing fixtures. Certain pipes that carry drinking water from the water source to the home may also contain lead.

When children are at school or preschool, 68% of parents polled believe it is safe for them to use the drinking fountain, while 5% of parents say the drinking fountains are unsafe, and 27% are unsure. The majority of parents also say their child has access to bottled water at school.

The U.S. Environmental Protection Agency recommends that schools test their drinking water for lead to confirm it is safe for students, but there aren't any universal requirements to do so.

In the absence of testing, bottled water can also be a solution, Clark says.

"The bottom line for parents is this: Your children need clean water to drink every day," she says. "If you have any concerns about the safety of the water at home or at school, it's very important to gather information, talk with experts, and take whatever action you think is necessary."

Think of the Amazon, and you probably think of jaguars, monkeys, or parrots. But many of the rainforest's secrets can be found hidden in its watery depths, from the fish swimming around its rivers and lakes And because these animals live in a river network that spans the South American continent, studying them helps conservationists understand why connected ecosystems are healthy ecosystems. Scientists from the Field Museum investigated fish populations in the South American country of Guyana, which helped to show why aquatic corridors matter in conservation.Their study, which they published in Frontiers in Forests and Global Change, makes an important case that protecting one tiny corner of the Guiana Shield can help protect rivers and biodiversity across the Amazon.

"I want to make a case for why this area should be protected, and I can tell that story using fish," says Dr. Lesley de Souza, conservation ecologist at the Field Museum. "We found over 450 species of fish in an area smaller than Connecticut. The entire Mississippi River basin has fewer than 200 species. We're talking about a pretty small area that has a ton of diversity."

In this study, de Souza focused on the lakes, rivers, and streams in the Rupununi region of central Guyana in northeastern South America. The area is inspiration for Pixar's balloon adventure, Up. For this study, De Souza traversed the same rocky outcroppings, breathtaking waterfalls, and lush jungles as the movie's characters, looking for fish. "We made several expeditions to the region and collected fish in a variety of habitats to better understand where they live, and further assess the habitats' conservation value, de Souza says. "We were taking fish out of rocks and caves, fish that live in woody debris in the water, sticking our hands in holes and hollow logs and finding fish. Anywhere there might be a fish, we checked."

What de Souza's team found was a wild variety of underwater life. They collected fish that looked like little silver knives. They pulled up their nets and found fish camouflaged as dead leaves. They found Arapaima, a ten-foot-long fish that gulps air at the water's surface in addition to breathing underwater with gills. Her team brought their specimens back to natural history museums (including the Field Museum) and completed the arduous task of identifying each one. The scientists then analyzed the fishes' habitats, and realized that the incredible diversity emerged from the unique environments of the Rupununi Portal.

De Souza calls this region a "portal" because when river levels rise in the rainy season, two river systems that remain separate during the rest of the year are connected by floodwaters, and fish can travel from the Guiana Shield to the heart of the Amazon. As the water recedes, the savannas and wetlands reemerge and the fish separate into their respective river systems again--until the next rainy season.

Conservation programs often overlook freshwater environments, focusing on land habitats instead. If you visited the dry Rupununi savannas outside of rainy season, you'd likely make the same mistake. De Souza's analysis helps show how conservation requires healthy watersheds, too--especially connected ones. "As the water goes up and down," de Souza explains, "the Rupununi acts like a heartbeat that pumps this incredible fish diversity throughout the country. If we don't protect it, that heartbeat stops." Better information about the fish species living in the area can provide evidence for why it needs to be protected.

And by protecting the lakes and rivers where the fish live, we can help the planet overall. The forests growing around these bodies of water are crucial in absorbing the carbon emissions that have created climate change. Conserving the Rupununi portal will yield long-term benefits for the entire planet.

Conserving the Rupununi portal will yield long-term benefits for the entire Amazon, but de Souza emphasizes the immediate local need for protection. "I focus on fish in this area because they're so important for the people," de Souza says. "Indigenous communities are the primary inhabitants of this region, and they are intimately connected to the forest, the savanna, and the wetlands. Their primary source of protein is fish. In order to maintain fish reproductive cycles and people's livelihoods, the entire system needs to stay intact."

Through this research, de Souza's team discovered a previously unknown portal farther south of the Rupununi portal. De Souza is excited to see what else researchers might discover there: "I have always been intrigued by the mystery of what is below the surface. Fish communities are an indicator of forest health, and they can tell us things we just can't learn on land."

Australia's first plant foods - eaten by early populations 65,000 years ago - have been discovered in Arnhem Land.

Preserved as pieces of charcoal, the morsels were recovered from the debris of ancient cooking hearths at the Madjedbebe archaeological site, on Mirarr country in northern Australia.

University of Queensland archaeobotanist Anna Florin said a team of archaeologists and Traditional Owners identified 10 plant foods, including several types of fruits and nuts, underground storage organs ('roots and tubers'), and palm stem.

"By working with Elders and co-authors May Nango and Djaykuk Djandjomerr, the team was also able to explain how the plants were likely used at Madjedbebe," Ms Florin said.

"Many of these plant foods required processing to make them edible and this evidence was complemented by grinding stone technology also used during early occupation at the site."

"The First Australians had a great deal of botanical knowledge and this was one of the things that allowed them to adapt to and thrive in this new environment.

"They were able to guarantee access to carbohydrates, fat and even protein by applying this knowledge, as well as technological innovation and labour, to the gathering and processing of Australian plant foods."

Madjedbebe is a sandstone rock shelter at the base of the Arnhem Land escarpment, and is Australia's oldest documented site.

Excavation director Professor Chris Clarkson from UQ's School of Social Science said he was surprised and delighted by the quantity of archaeobotanical evidence recovered from the site.

"Madjedbebe continues to provide startling insights into the complex and dynamic lifestyle of the earliest Australian Aboriginal people," Professor Clarkson said.

The oldest occupation layer at Madjedbebe also holds evidence for the oldest edge ground stone axes in the world, the earliest grindstone technology outside Africa, the early shaping of stone spearheads, many kilograms of ground ochre, and the first recorded use of reflective pigments in the world.

"The site is an important cultural place to Mirarr people today who strive to protect their heritage from numerous threats, including mining," Ms Florin said.

Justin O'Brien, CEO of Gundjeihmi Aboriginal Corporation which represents the Mirarr Traditional Owners, said that research on country - working in meaningful partnership with Traditional Owners - was a powerful way to share Mirarr's enduring culture with a broader audience.

The study is published in Nature Communications (DOI: 10.1038/s41467-020-14723-0).

The Swedish team responsible for uterine transplantation research has, for the first time, transplanted a uterus from a deceased donor. The operation proceeded without complications and the recipient is doing well.

The transplant was done in December 2019 under the supervision of Mats Brannström, consultant physician and professor of obstetrics and gynecology at the University of Gothenburg. The research team plan to carry out another five transplants of a deceased donor's uterus in the course of 2020 and 2021.

To date, three babies in the world have been born after transplantation of the uterus of a deceased donor: one in Brazil, followed by two in the U.S. The first such birth in Sweden may take place in 2021 at the earliest.

"It feels good to have started. Now we've also been able to tell the other study participants on the waiting list that the first transplant's been done," Mats Brannström says.

Every previous uterine transplant in Sweden has involved a living donor -- often the recipient's mother, and in some cases a close friend. The purpose of trying out the new method is to expand the range of options ahead of the possible establishment of uterine transplantation as a treatment.

The number of potential donors would then increase. Even a woman with no suitable donor close to her could be considered for transplantation. Moreover, there is no need for a living donor to undergo anesthesia and surgery.

The donor in the present case was a woman who had previously given birth, and was of fertile age at the time of her sudden death. Her survivors were asked about her attitude toward organ donation, as always when a potential donor is not listed in the donation register.

"They were also asked specifically about her uterus, since it's a new organ in this context. Under the research ethics permit for the study, special mention of the uterus must be made," Brannström explains.

The 30-year-old woman uterus recipient was called to Sahlgrenska University Hospital for her operation at short notice. She was able to go home after five days, and is now being monitored and receiving care in the same way as every other woman with a transplanted uterus in Sweden.

The plan is this fall, ten months after surgery, to initiate attempts to make the woman pregnant. This will be done by inserting into her transplanted uterus an embryo that has come into being through in vitro fertilization (IVF) before the transplantation.

Since the 2014 Swedish breakthrough, when the first birth worldwide from a transplanted uterus took place, another eight babies -- including three sibling pairs -- have been born in "Study 1." The latest birth in this study took place in January 2020.

In 2019, a baby was born in the robot project, "Study 2." This study involved new technology, with a robot-assisted keyhole technique enabling less invasive surgery on the donor. The latest of the eight operations in this study was performed in November 2019. One pregnancy is underway.

Some participants in Studies 1 and 2 were approved for transplants and underwent IVF but, for various reasons, have been unable to complete the study. Either because it was shown, late in the investigation, that the vessels of the donor's uterus were not of good quality, or because an already surgically inserted uterus needed to be removed. These are the women included in the trials involving transplantation of a deceased donor's uterus.

Numerical simulations, generally based on equations that describe a given model and on initial data, are being applied in an ever-expanding range of scientific disciplines to approximate processes at given points in time and space. With so-called inverse problems, this critical data is missing--researchers must reconstruct approximations of the input data or of the model underlying observable data in order to generate the desired predictions.

While techniques for doing so already exist, they are ill-defined, unable to assign unique interpretations or values to a given point. As an example, in the most commonly used method for solving such problems, the so-called maximum entropy (MaxEnt) approach, prior knowledge is added by specifying a default distribution that corresponds to expected results in the absence of data. The algorithm iteratively searches for a distribution that maximizes entropy with respect to this default distribution while also generating a function close to existing data. The approach includes a parameter used to weigh the relative importance between the entropy and the error terms. There are several methods for fixing it that often yield different results when applied in practice.

In the paper Artificial Neural Network Approach to the Analytic Continuation Problem, QuanSheng Wu, a scientist and Romain Fournier, a master's student at EPFL's C3MP, led by Professor Oleg Yazyev, and colleague Professor Lei Wang at the institute of Physics of the Chinese Academy of Sciences present a supervised learning approach to the problem. Based on an artificial neural network (ANN)--highly versatile thanks to an ability to approximate continuous functions under mild assumptions and because of powerful libraries allowing for the efficient implementation of different ANN architectures that can be tailored to take advantage of data structures--the new method appears to be as accurate as MaxEnt and considerably cheaper computationally.

In a first test of the ANN framework, the researchers chose to examine a system that has an analytical solution, but is difficult to solve using MaxEnt--namely, the time-correlation function of the position operator for a harmonic oscillator linearly coupled to an ideal environment. The Hamiltonian, or operator generally corresponding to the total energy of the system, is known in this case, and the data of interest--the imaginary-time correlation function--can be generated by quantum Monte Carlo (QMC) simulations.

The analytic solution gives the relation of the power spectrum to an imaginary-time correlation function and as such provided physically relevant training data for the ANN model. The researchers trained the ANN with the generated data and then tested it by obtaining the imaginary-time correlation function calculated in the earlier step by QMC. The model trained on the entire dataset showed almost perfect agreement with the analytic solution. MaxEnt failed to give accurate results, though the researchers noted that better results would likely have been obtained by computing the correlation function on a larger number of points.

To further test the model in a practical way, the researchers looked to recover the electron single-particle spectral density in the real frequency domain from a Green's function in the imaginary time domain. While both the ANN and the MaxEnt models were able to predict starting spectral functions accurately for the lowest level of noise, MaxEnt tended to suppress peaks in the predicted spectral function with increasing noise in the system. These results show that the ANN model is versatile and robust against noisy data.

The new method is also computationally more efficient. ANN allowed direct mapping between Green's functions and the spectral densities and can in that sense solves the problem directly. MaxEnt on the other hand is iterative and generates trial functions until convergence is reached. With the computational set-up used in the paper, the time required for converting a given number of pairs at a given level of noise was 5 seconds in the case of ANN compared with the 51 minutes that MaxEnt would have needed using the same setup.

The researchers said that such ANNs are likely to be able to solve other inverse problems, provided that relevant datasets--derived, for instance, using available experimental results combined with data augmentation techniques--can be constructed. The trained models resulting from the work can be obtained from a public repository at GitHub here: https://github.com/rmnfournier/ACANN.

An organic semiconductor photocatalyst that significantly enhances the generation of hydrogen gas could lead to more efficient energy storage technologies.

The combustion of fossil fuels is leading to dangerous climate change, driving the search for cleaner renewable energy sources. Solar energy is by far the most abundant renewable energy source, but unlocking its potential requires a way to store it for later use.

A standard method for storing solar energy is in the chemical bonds of molecular hydrogen using hydrogen evolution photocatalysts (HEPs). Currently, most HEPs are made from single-component inorganic semiconductors. These can only absorb light at ultraviolet wavelengths, which limits their ability to produce hydrogen.

A team led by Iain McCulloch from the KAUST Solar Center, in partnership with researchers from the United States and the United Kingdom, has now developed HEPs made from two different semiconducting materials. They incorporated these materials into organic nanoparticles that can be tuned to absorb more of the visible light spectrum.

"Traditionally, inorganic semiconductors have been used for photocatalytic applications," says Jan Kosco, first author of the study. "However, these materials absorb primarily UV light, which comprises less than five percent of the solar spectrum. Therefore, their efficiency is limited."

The team first used a method called miniemulsion, in which a solution of the organic semiconductors is emulsified in water with the aid of a stabilizing surfactant. Next, they heated the emulsion to drive off the solvent, leaving behind surfactant-stabilized organic semiconductor nanoparticles.

By varying the surfactant, they were able to control the structure of the nanoparticles, transforming them from a core-shell structure to a mixed donor/acceptor structure. The blended structure allowed them to introduce a heterojunction between the layers of the donor polymer and nonfullerene acceptor.

"Both structures absorb light at the same rate," explains Kosco, "but in the core-shell structure, only photogenerated holes reach the surface; however, in the mixed structure, both holes and electrons reach the surface of the nanoparticles, resulting in enhanced generation of hydrogen.

The HEPs exhibited hydrogen evolution rates an order of magnitude beyond what is currently achievable with single-component inorganic HEPs. This lays the foundations for next-generation energy storage technologies.

"We are currently studying the performance of nanoparticles formed from different blends of semiconductors to better understand their structure-activity relationships," says McCulloch. "We are looking to design nanoparticle photocatalysts for other photocatalytic reactions, such as oxygen evolution or carbon dioxide reduction."

In the recent article published in Science Bulletin, the researchers develop an effective organic-cation intercalation strategy to manipulate the interlayer coupling of layered materials, and obtain a class of organic-inorganic hybrid crystals with tailored topological properties and enhanced superconductivities.

Reducing dimensionality is a direct pathway to manipulate interlayer coupling of layered materials for inducing exotic properties. For instance, WTe2, which is a non-superconducting Weyl semimetal in the bulk, could host quantum spin Hall effect with superconducting transition temperature Tc ~ 0.82 K when the thickness is decreased to monolayer. However, reducing dimensionality requires complex growth or exfoliation and the monolayer samples are often unstable in ambient conditions. Developing an effective and facile method to manipulate interlayer coupling to achieve tailored properties is therefore highly desirable.

Recently, researchers led by Shuyun Zhou and Pu Yu from Tsinghua University co-developed an organic-cation intercalation strategy for layered materials. They start form Weyl semimetals MoTe2 and WTe2, and the intercalated samples exhibit tailored topological properties, enhanced superconductivities and good sample stabilities. The intercalated MoTe2 shows Tc of 7.0 K as compared to Tc of 0.25 K in its bulk counterpart, and is comparable to monolayer flake. More importantly, the intercalated WTe2 exhibits enhanced Tc of 2.3 K, which is 2.8 times of Tc ~ 0.82 K in the monolayer sample, suggesting that the intercalation method is very effective in boosting the superconductivity. Such manipulation of both band topology and superconductivity in intercalated MoTe2 and WTe2 provides a promising platform to realize topological superconductivity and Majorana zero-mode.

The impact of the intercalation methodology developed in this work on future engineering of other layered materials is also far-reaching. As highlighted by Xianfeng Duan from UCLA in the News & Views published in the same issue, "The molecular intercalation approach offers a versatile strategy to tailor the dimensionality and topological nature of the layered crystals, and defines an entirely new class of organic-inorganic superlattice structures for elaborately engineering the electronic states and complex band-structure topology to enable exotic properties and devices."

A University of Kent study has found that cultivated foods offer chimpanzees in West Africa more energetic benefits than wild foods available in the region.

The findings have made a significant development for our further understanding into human-primate coexistence and can help to inform conservation efforts for future improvement, particularly in locations where agricultural expansion is encroaching on tropical forests.

Dr Nicola Bryson-Morrison and Dr Tatyana Humle of Kent's Durrell Institute of Conservation and Ecology, examined the macronutrient content of 24 wild and 11 crop foods consumed by chimpanzees in Bossou, Guinea, West Africa.

It was found that cultivated fruits were higher in easily digestible carbohydrates and lower in insoluble fibre than wild fruits, while wild fruits were higher in protein. Higher easily digestible carbohydrates provide more energy.

Oil palm food parts were relatively rich in carbohydrates, protein, lipids, and fermentable fibre, adding nutritional support for the importance of the oil palm for West African chimpanzees inhabiting human-dominated environments.

When compared with published macronutrient measures of crops from Bulindi, Uganda, East Africa, the composition of wild fruits, leaves, and pith were consistent with previous reports for primate diets. Furthermore, no differences were found in the composition of cultivated fruits, suggesting macronutrient content alone does not explain differences in primates' crop selection. This confirms the idea that food-crop selection in chimpanzees is partly cultural.

Dr Bryson-Morrison said: 'Our research has built on the current understanding of chimpanzee feeding ecology within forest?agricultural mosaics. By providing further validation that nutritionally dense crops offer primates energetic benefits over wild foods, this study has widened scope for more research into human-primate interactions in relation to shared resources and species-specific dietary needs.'

Exploiting a vulnerability in the mobile communication standard LTE, also known as 4G, researchers at Ruhr-Universität Bochum can impersonate mobile phone users. Consequently, they can book fee-based services in their name that are paid for via the mobile phone bill - for example, a subscription to streaming services.

"An attacker can book services, for example stream shows, but the owner of the attacked phone would have to pay for them," illustrates Professor Thorsten Holz from Horst Görtz Institute for IT Security, who discovered the vulnerability together with David Rupprecht, Dr. Katharina Kohls and Professor Christina Pöpper. The team from Bochum will present the results on 25 February 2020 at the Network Distributed System Security Symposium, NDSS for short, in San Diego, USA. Details of the attacks are also available on the website http://www.imp4gt-attacks.net.

According to the researcher, the vulnerability may also affect investigations of law enforcement agencies because attackers can not only make purchases in the victim's name, but can also access websites using the victim's identity. For example, an attacker can upload secret company documents and to network operators or law enforcement authorities, it would look as if the victim is the perpetrator.

Almost all mobile phones and tablets at risk

The discovered vulnerability affects all devices that communicate with LTE, i.e. virtually all mobile phones, tablets, and some connected household appliances. Only changing the hardware design would mitigate the threat. The Bochum-based team is attempting to close the security gap in the latest mobile communication standard 5G, which is currently rolled out. "For a technical perspective this is possible," explains David Rupprecht. "However, mobile network operators would have to accept higher costs, as the additional protection generates more data during the transmission. In addition, all mobile phones would have to be replaced and the base station expanded. That is something that will not happen in the near future."

As early as 2018, the group had already drawn attention to security gaps in LTE, through which attackers can redirect users to fake websites and retrieve their passwords (https://news.rub.de/english/press-releases/2018-06-28-it-engineering-security-gaps-identified-lte-mobile-telephony-standard).

Attacker has to be nearby

The problem is the lack of integrity protection: data packets are transmitted encrypted between the mobile phone and the base station, which protects the data against eavesdropping. However, it is possible to modify the exchanged data packets. "We don't know what is where in the data packet, but we can trigger errors by changing bits from 0 to 1 or from 1 to 0," as David Rupprecht elaborates. By provoking such errors in the encrypted data packets, the researchers can make a mobile phone and the base station decrypt or encrypt messages. They not only can convert the encrypted data traffic between the mobile phone and the base station into plain text, they can also send commands to the mobile phone, which are then encrypted and forwarded to the provider - such as a purchase command for a subscription.

The researchers from Bochum use so-called software-defined radios for the attacks. These devices enable them to relay the communication between mobile phone and base station. Thus, they trick the mobile phone to assume that the software-defined radio is the benign base station; to the real network, in turn, it looks as if the software-defined radio was the mobile phone. For a successful attack, the attacker must be in the vicinity of the victim's mobile phone.

Face blindness (prosopagnosia) is the inability to recognise faces. Much as people with dyslexia find it difficult to distinguish letters, people with face blindness are unable to "read" the special features that make faces unique, and which enable those without the condition to distinguish between people and recognise those we have met before.

Approximately 2% of the population have severe problems in recognising faces. Nobody knows why, and the researchers set out to identify what is different about the brains of this particular group. A Danish-Norwegian team of researchers scanned 15 adult Danes with face blindness and 33 control subjects while they looked at pictures of faces, objects, buildings or words, and compared the two groups' brain activity. The surprising findings are described in an article in the scientific journal Brain Communications (Oxford University Press)

Human beings process different visual impressions in different parts of the brain. The research team expected that activity in a particular area on the right-hand side of the brain (the "fusiform face area") would be different in people with face blindness, as this is a key part of the brain network we use when looking at faces.

This turned out not to be the case. Brain activity in this area was the not different betweenthe groups.

To their surprise, the scientists instead noted a reduced level of activity in a corresponding area in the left side of the brain in those with face blindness compared to the control subjects.

However, when the two groups looked at pictures of buildings or words instead of faces, there was no difference in brain activity. In fact, activity in the "visual word form area" was completely normal in those with face blindness, although this is situated right next to where the researchers found differences when participants looked at faces. In other words, reduced activity was observed in a very specific area while the subjects wwere performing a very specific action.

"It seems that we have been looking in the wrong half of the brain to identify what is different in people with face blindness. However, we are now closer to pinpointing the coordinates for face blindness in the brain," says Randi Starrfelt, professor in neuropsychology, University of Copenhagen.

Face blindness as a result of brain damage was first documented in 1947. The condition has since been observed in a number of people after stroke or some other form of brain injury. Congenital face blindness was first described in 1977, but it is only recently that researchers have discovered how common this condition is.

In the last decade or so, researchers have been searching for anomalies in the brains of people with face blindness. Randi Starrfelt and her colleagues sought out previous research that identified this less active part of the left side of the brain, which she and her research team have now mapped. The team found several mentions of the phenomenon in previous studies.

"While other researchers have noted this difference, most didn't seem to think it was particularly important. It has received surprisingly little attention," she says.

The team do not yet know the cause of face blindness, only that it is partially hereditary and probably arises due to a developmental disorder while the brain is being formed. At that stage of life, a "neural migration" takes place in the brain, during which neurons move to their final position. It may be an abnormality in this process that causes the condition.

"We know so little about face blindness, so just being able to pinpoint which areas in the brain are affected is a step towards hopefully one day helping those with the condition," she says.

Life can be quite difficult for people with face blindness, many of whom are unable to recognise family members and friends. Some even find it difficult to recognise themselves in photographs or in the mirror.

"Some people with face blindness don't recognise you if you pop out the door and come back in again. Many become quite adept at identifying people via secondary characteristics such as voice, patterns of movement, jewellery, glasses and hair, but many live with the condition for years before it is diagnosed. They - and the people closest to them - may think that they are unable to concentrate or that they are forgetful, arrogant and dismissive even, or that they suffer from a psychological development disorder such as autism. The reality is that with face blindness they are unable to recognise people, especially if they bump into them unexpectedly," says Starrfelt, who is often contacted by people who have had the condition for a long time without realising it.

Marine sediments cover more than two thirds of our planet's surface. Nevertheless, they are scarcely explored, especially in the deeper regions of the oceans. For their nutrition, the bacteria in the deep ocean are almost entirely dependent on remnants of organisms that trickle down from the upper water layers. Depending on how they process this material, it either remains in the depths of the ocean for a long time or moves back to the surface as carbon dioxide. Thus, sea-floor bacteria play an important role in the global carbon cycle, which makes them an exciting and important research object.

Global players at the seafloor

The research team around Christina Bienhold and Katy Hoffmann from the Max Planck Institute in Bremen and Pierre Offre, who now works at the NIOZ on the island of Texel, has now identified and characterised a particularly dominant group of microbes. "Although these bacteria have been known in the literature for some time," Bienhold explains, "nobody has paid much attention to them until now." While the team focused on the role of this group in the deep sea, other researchers at the Max Planck Institute for Marine Microbiology investigated its importance in coastal sediments. "Only now does it become clear how numerous and widespread members of Woeseiales are," Bienhold continues. An impressive 40 million cells inhabit each millilitre of deep-sea floor - together with a billion other bacteria. In a thimble full of sediment, there are thus about 120 million cells of Woeseiales. "We know of no other group of bacteria that occurs in the ocean floor at such high abundances." Extrapolated to the entire deep-sea floor, the worldwide population of Woeseiales would amount to 5 x 1026 cells, the authors estimate. "Considering that these estimates include neither the coastal sediments nor the deep biosphere, these bacteria may be one of the most common groups of microorganisms on Earth," explains Bienhold.

A group with varied ecological roles

In their study, the authors present an ecological synthesis summarising current knowledge about the diversity and environmental distribution of these bacteria. The synthesis was built upon DNA sequence data, which were deposited in public databases over the last two decades, but also included new data, some of which was generated from arctic deep-sea sediments collected at the AWI-maintained long-term observatory HAUSGARTEN. "The analyses reveal that Woeseiales accommodate a myriad of organisms with varied ecologies," explains Pierre Offre, lead author of the study. "For example, different species of Woeseiales co-exist together at any location of the seabed, where they probably fulfil different ecological functions. Our study provides a first ecological guide to these fascinating organisms."

Moreover, the data now available indicate that members of Woeseiales could feed on so-called proteinaceous matter, such as the remains of cell walls and membranes or other leftovers of dead organisms. Considering that proteins are a major source of nitrogen ¬- a fundamental nutrient for all life forms - in marine seafloor sediments, the potential ability of Woeseiales bacteria for protein degradation, may be ecologically important for the re-cycling of nitrogen in benthic ecosystems." I am convinced that further studies of these bacteria will provide new insights into the carbon and nitrogen cycles in marine sediments," concludes Offre, who continues investigating these microorganisms to understand the secret of their ecological success, together with his research team at NIOZ.

Combining experiment and theory, researchers from the Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI) and the Max Planck Institute of Microstructure Physics have disentangled how laser pulses can manipulate magnetization via ultrafast transfer of electrons between different atoms.

Few nanometer-thin films of magnetic materials are ideal test objects to study fundamental problems in magnetism. Furthermore, such thin magnetic films have important technological applications. For example, they are used in magnetic mass data storage devices, e.g., in the magnetic hard drives used in cloud data storage centers. While in current technology the magnetization in these thin films is manipulated via magnetic fields, it is also possible to influence the magnetization using laser pulses. When exposed to ultrashort light pulses of only a few tens of femtosecond duration (1 femtosecond = 1 millionth of one billionth of a second), it is observed that the magnetization below the laser spot changes. In simple systems, this change often corresponds to a simple decrease in the magnetization magnitude. In more complex material systems, however, the light pulse can also permanently reverse the magnetization. In such cases, one speaks of all-optical magnetization switching, with obvious potential for application. The remarkable speed of this switching process is not yet understood. For this reason, research groups around the world are investigating the microscopic processes underlying "femtomagnetism".

Researchers from the Max Born Institute in Berlin and the Max Planck Institute for Microstructure Physics in Halle, combining experimental and theoretical work, have now witnessed a new microscopic process "at work", which was predicted only recently. The process, called optical intersite spin transport (OISTR), can occur when suitable atoms of different types are adjacent in a solid. Under suitable conditions, a light pulse triggers a displacement of electrons from one atom to its neighbor. Importantly, this happens predominantly with electrons of a particular spin orientation and thus influences the local magnetization. This process takes place during optical excitation and does not depend on secondary mechanisms. It is, therefore, the fastest process imaginable leading to a light-induced change in magnetism.

An atom in a solid that is magnetized can be pictured as having separate reservoirs of spin-up and spin-down electrons, which are filled to a different extent. For a Cobalt (Co) and Platinum (Pt) atom which are neighbors of each other in a CoPt alloy, this is sketched in Figure 1. The difference in the number of spin-up and spin-down electrons (drawn in red and blue) determines the amount of magnetization of the atom. If the magnetization is reduced, the number of the two spin types has to equalize. A well-known process to level both reservoirs at one atom is a spin-flip, in which, for example, a spin-down electron turns into a spin-up electron - represented by a jump from the blue bucket into the red bucket in Figure 1. These spin-flips predominantly occur at heavy atoms like Pt, where the spin reacts particularly sensitive on the motion of the electron - physicists speak of a large spin-orbit coupling. The angular momentum emitted in this spin-flip process is absorbed by the entire array of atoms in the solid.

In the present study, published in the journal Nature Communications, the researchers have investigated two model systems, a pure Co layer and a CoPt alloy. The team monitored the absorption of ultrashort pulses of soft x-rays with controlled wavelength and polarization after a laser pulse excitation and compared their experimental findings to theoretical calculations as shown in Figure 2. In this way, the changes in the numbers of electrons with spin-up and spin-down triggered by the initial laser pulse could be studied separately for the Co and Pt atoms.

The comparison between the simple system containing exclusively Co atoms (left panels in Figure 2) and the alloy, containing both Co and Pt atoms (right panels) shows pronounced differences in the absorption behavior, which are independently predicted by the theoretical calculations. These differences come about as in the CoPt alloy an additional process can take place in which electrons are transferred between the different types of neighboring atoms.

Due to the laser pulse, electrons within the solid are transferred from the Pt atoms to the Co atoms. It turns out that these are preferentially spin-down electrons because many empty states for spin-down electrons are available at the receiving Co site. At the Co atom, the transferred electrons, thus, increase the level of the spin-down electrons (red in Figure 2), making it more similar to the spin-up reservoir and hence reducing the magnetic moment of the Co atom. This OISTR process between Pt and Co is accompanied by a leveling of the electron reservoirs locally at the Pt atoms via spin flips. This spin-flip happens efficiently at the heavy Pt atoms exhibiting large spin-orbit-coupling and only to a much lesser extent at the lighter Co atoms.

The detailed results of the study show that the ability to optically manipulate magnetization via optical intersite spin transport depends crucially on the available states for spin-up and spin-down electrons of the atoms involved. These states can be tailored by bringing the right types of atoms together in novel materials. The understanding of the microscopic mechanisms involved in the optical manipulation of the magnetization, thus, paves the road to a rational design of new functional magnetic materials, allowing for ultrafast control of magnetization via laser pulses.