Brain

Proteins often form assemblies and thereby perform sophisticated functions in cells as best exemplified by proteasomes, which are huge enzyme complexes functioning as proteolytic machines. In eukaryotes, this proteasome formation is not a spontaneous process but is assisted by several other proteins, termed proteasome-assembling chaperones. Paradoxically, archaeal genomes encode proteasome-assembling chaperone homologs, denoting a shared ancestry between genes, although archaeal proteasome formation is a spontaneous process not requiring these chaperones. Therefore, the functional roles of the archaeal chaperone-like proteins remain unknown. The collaborative groups, including researchers at Exploratory Research Center on Life and Living Systems (ExCELLS), Institute for Molecular Science (IMS), and National Institute for Physiological Sciences (NIPS) of National Institutes of Natural Sciences found that a chaperone-like protein originating from a hyperthermophilic archaeon together with another protein from the same species, whose function is also unknown, are assembled together into unique structures. The integrated biophysical data they obtained using native mass spectrometry, solution scattering, high-speed atomic force microscopy, and electron microscopy, along with atomic structure modeling, revealed that this complex forms a five-column tholos-like architecture, harboring a large central cavity, which can potentially accommodate biomolecules, such as proteins. This characteristic architecture of archaeal protein complex provides insight into the molecular evolution between archaeal and eukaryotic proteins. Furthermore, their findings offer a novel framework for designing functional protein cages as molecular warehouses or shelters that are stable in high temperatures.

It is now possible to predict who the best candidate for receiving an organ transplant is, know whether clients of a bank will return the loans they request, choose the films that best coincide with the interests of consumers or even select someone's ideal partner. Mathematical algorithms constantly analyse millions of items of data, identify patterns and make predictions about all areas of life. But in most cases, the results give little more than a closed prediction that cannot be interpreted and which is often affected by biases in the original data. Now, a team from the research group SEES:lab of the Department of Chemical Engineering of the Universitat Rovira I Virgili and ICREA has made a breakthrough with the development of a new algorithm that makes more accurate predictions and generates mathematical models that also make it possible to understand these predictions. The results of this research have just been published in the journal Science Advances.

"The aim of our study was to create what is known as a scientific robot, an algorithm that can apply the knowledge and expertise that a researcher has to interpret data," explains Marta Sales-Pardo, one of the authors of the paper. The results provided by the algorithm are characterised by the fact that they are interpretable. "It is as if someone had drawn up a law or a theory on the system that is being studied. The algorithm gives you the mathematical relations between the variables it has analysed and it does so completely independently," adds Roger Guimerà, an ICREA researcher from the same group.

When a company has an enormous amount of data that it wishes to exploit, it can do so by employing someone to try various models, propose formulas and find which one works best by carrying out experiments to validate them. This will lead to a mathematical formula that makes it possible to model the system but it involves a considerable investment in time and money. Another possibility is to find a specialist in machine learning, a scientific discipline in the field of artificial intelligence that creates systems that identify complex patterns in enormous data sets, learn automatically and produce a "black-box" model that can make predictions. However, these systems provide no other information and if the prediction fails it is impossible know where the error lies and what needs to be done to prevent it. The algorithm developed at the URV takes the best of the two cases: it processes the data automatically, quickly and reliably, as the machine learning system does, and it also produces a result that is an interpretable model.

The algorithm can be used to analyse and interpret data from any discipline in a process that is much more agile and efficient than those in existence to date. But the real added value is the information that the system provides. "In medicine, for example, if you have to take a decision based on data it is very important to understand why each decision has been taken and the risk of making a mistake," explains Guimerà. "Although the algorithm has also shown that it is highly accurate, the most important thing is that you can understand the results because you have built a machine scientist that, with no previous knowledge, can take a set of data and develop a theory that solves the problem posed," adds Ignasi Reichardt, another researcher on the team.

In this study, the algorithm has been applied to a fundamental problem of fluid physics with the collaboration of the research group Experimentation, Computation and Modelling in Fluid Mechanics and Turbulence of the URV's Department of Mechanical Engineering.

(Boston)--For the first time, researchers describe the genetic program behind primordial lung progenitors--embryonic cells that give rise to all the cells that form the lining of the respiratory system after birth. They believe this study has long-term implications for the treatment of diseases affecting the respiratory system, such as chronic obstructive pulmonary disease (COPD), alpha-1 antitrypsin deficiency and cystic fibrosis.

Diseases affecting the lungs are not easily treatable and result in significant morbidity and mortality worldwide. Specialized stem cells with the potential to self-renew have been proposed as a critical component of tissue homeostasis for many organs, including the lung. Similar cells can be engineered in vitro and used in the future in cell replacement therapies for respiratory diseases.

Using a genetically modified experimental model, researchers from the Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, were able to isolate and describe the genetic program of the earliest lung progenitor cells and understand the signals that instruct them. They then used computational methods that helped them define how similar their engineered lung cells are to the in vivo progenitors.

"Our findings define in great detail a rare, transient cell, namely the primordial lung progenitor. The knowledge generated from this study will be of great value in the derivation of human primordial lung progenitors in culture, since the equivalent stage in human lung development is not accessible," explained corresponding author Laertis Ikonomou, PhD, assistant professor of molecular and translational medicine at Boston University School of Medicine.

Respiratory system diseases, such as COPD, cystic fibrosis and lung interstitial disease severely affect quality of life. "We hope that our findings will eventually lead to more protocols for, transplantable lung epithelial cells for treatment of such diseases and for drug development," added Ikonomou.

This work is the result of close collaboration with the laboratory of Darrell N. Kotton, MD, director of the CReM (last and co-corresponding author). Other coauthors include BU investigators Michael J. Herriges, PhD; Sara L. Lewandowski, PhD; Robert Marsland III, PhD; Carlos Villacorta-Martin, PhD; Ignacio S. Caballero, MBA; Reeti M. Sanghrajka, PhD, Keri Dame, PhD; Maciej M. Ka?du?a, PhD; Julia Hicks-Berthet; Matthew L. Lawton; Constantina Christodoulou, PhD; Eric Kolaczyk, PhD; Xaralabos Varelas, PhD and Pankaj Mehta, PhD. University of Pennsylvania investigators David B. Frank, PhD and Edward E. Morrisey, PhD; John M. Shannon, PhD from Cincinnati Children's Hospital and Attila J. Fabian from Biogen.

These findings appear online in the journal Nature Communications.

DNA in preserved museum specimens can allow scientists to explore the history of species and humanities impact on the ecosystem, but samples are typically preserved in formaldehyde which can damage DNA and make very difficult to recover.

Researchers have used a vortex fluidic device (VFD) to speed up DNA extraction from an American lobster preserved in formaldehyde - with the results providing a roadmap for exploring DNA from millions of valuable and even extinct species in museums worldwide.

Flinders PHD candidate Jessica Phillips says processing the preserved tissue from museum specimens in the VFD breaks apart proteins, releasing DNA which offers important historical genetic information.

"DNA extraction is achieved by processing the preserved tissue in an enzyme solution in the VFD. This enzyme breaks apart the proteins, releasing the DNA which can be analysed. By using the VFD we are able to accelerate this process from days to hours," says Ms Phillips.

"For 150 years these samples have been preserved in formaldehyde which can damage the DNA and also make DNA difficult to recover. We used mechanical energy in a vortex fluidic device (VFD) to accelerate the extraction by processing the preserved tissue in an enzyme solution in the VFD."

This work is a collaboration between University of California, Irvine (UCI), The Department of Organismic and Evolutionary Biology at Harvard University, and Flinders University.

Researchers say the results provide a roadmap for exploring DNA from millions of historical and even extinct species in museums worldwide.

Research Chair of Clean Technology Research Professor Colin Raston says the work builds on the body of about 80 papers that his research group has published about the vortex fluidic device.

"Applications of the VFD are rapidly expanding, but this has only been possibly by internal collaboration. The DNA extraction application involved collaboration with two other research laboratories headed by Professor Greg Weiss at UCI and Professor Peter Girguis at Harvard."

"We have only scratched the surface about what is possible for this device," says Professor Raston."

During embryogenesis in the nematode Caenorhabditis elegans, the first cell division occurs transverse to the long axis of the fertilized egg. In a new study, biophysicists at Ludwig-Maximilians-Universitaet (LMU) in Munich have now shown how this axis is reliably selected.

Many fundamental processes in biology depend on the formation of patterned distributions of specific proteins within cells. Examples include the localization of the cleavage plane prior to cell division and the direction of tissue growth. One paradigmatic example of cell polarization is the first cell division during embryogenesis in the nematode worm Caenorhabditis elegans, a well-established experimental model organism in developmental biology. In this system, the location of cell division is firstly determined by the so called PAR proteins (partitioning defective proteins). Since it is essential for the subsequent course of development, this operation must be tightly controlled. LMU biophysicist Erwin Frey and his research group have now identified two crucial mechanisms that contribute to the robust orientation of the polarized pattern of the PAR proteins along the long axis of the fertilized egg. The new findings appear in the online journal Nature Communications.

The first cell division of the elongated C. elegans egg is asymmetric, and determines the future front and back side of the worm. This anterior-posterior polarity of the embryo is defined by membrane-binding PAR proteins, which can be divided in two subgroups, aPARs and pPARs, binding to the anterior and posterior, respectively. In the unfertilized egg, all PAR proteins diffuse freely and are evenly distributed throughout the cell. In principle, all of them could bind to the membrane at any point. Due to a mutual antagonism between aPARs and pPARs each group of proteins soon builds a domain on the membrane excluding the other group from the membrane. "We use mathematical models and numerical simulations to explore the mechanisms that underlie the formation of protein patterns in cells. In this study, we analyzed what determines the orientation of the aPAR-pPAR pattern, specifically, what aligns the polarized pattern with the long axis of the egg" says Raphaela Gessele, a PhD student in Frey's team and lead author of the paper.

Each group of PARs can bind to the membrane and antagonistically remove the other protein group from the membrane by phosphorylation. Among the aPARs A1 acts as a linker for A2 to collocate at the membrane. In the cytosol, the phosphorylated proteins are dephosphorylated only after some delay, enabling them to diffuse away from the detachment point before binding again. Simulations showed that the dynamics of cycling between the phosphorylated and dephosphorylated states of the aPARs and pPARs are a critical factor in the process of axis selection at patterning onset. Thus, the average duration of the delay between dissociation from the membrane and recovery of binding affinity is a vital parameter in determining the first orientation of the protein pattern along the long axis.

The study shows that the ellipsoidal geometry of the fertilized egg influences the patterning process. Owing to the difference in curvature, recently detached and freely diffusing proteins are more likely to reencounter the membrane at the poles than elsewhere in the cell. "Antagonistic proteins exclude each other proportional to their membrane concentration which stabilizes domains. Depending on the respective lifetimes of the phosphorylated forms, the protein domains localize in the midcell region or at the cell poles at first, however, the final polarization in the three dimensional embryo is always aligned with the long axis," says Gessele.

Selection of the long axis polarization in the ellipsoidal embryo is further favored by the fact that the area of the transition zone between aPAR and pPAR domains, in which the two groups of proteins mutually exclude each other from the membrane, is minimized, reducing energetic costs. Owing to the elongated geometry of the fertilized egg, this is best achieved if each domain is confined to one pole. "Cell polarization plays a crucial role in very many biological systems," Frey points out. "Our results yield new insights into the mechanisms that cells employ to regulate this fundamental process."

Drifting algae in the Austral Ocean can bring invasive species to the Antarctic coasts, according to a study published in the journal Scientific Reports. The new study describes the first scientific evidence of a potentially invasive and colonial species -the marine bryozoan Membranipora membranacea- which reaches the Antarctic latitude islands in macroalgae that drift in the marine environment.

The new study on biodiversity in the Antarctic ecosystems is led by the lecturer Conxita Àvila, from the Faculty of Biology and the Biodiversity Research Institute (IRBio), and counts on the participation of the experts from the Institute of Marine Sciences (ICM-CSIC), the British Antarctic Survey (BAS) and the University of Hull (United Kingdom).

Passengers into the cold

Tourism, maritime transport and scientific research are some human activities that favoured the expansion of non-native organisms -insects, plants, etc.- in the fragile terrestrial ecosystems of the Antarctica. In these extreme habitats, the drifting of algae and plastics driven by the wind and marine currents can be natural mechanisms that favour the arrival of exotic organisms in the marine environment.

Now, the new article in Scientific Reports describes for the first time the arrival of organisms towards Antarctic latitudes through floating macroalgae coming from distant ecosystems in the marine environment. "Although this way of natural expansion was known in other natural ecosystems in the planet, in Antarctica, this phenomenon has taken a special scientific relevance as a potential mechanism to introduce new species in the Antarctic ecosystems", notes the lecturer Conxita Àvila, from the Department of Evolutionary Biology, Ecology and Environmental Sciences and IRBio.

Bryozoans, molluscs, annelids, arthropods, echinoderms, cnidarians and sponges are some of the unexpected passengers that travelled thousands of kilometres on top of macroalgae that were driven by the wind and marine currents to the Antarctic and Subantarctic islands. With a laminated structure and large dimensions, these kelps -the species Macrocystis pyrifera and Durvillaea antarctica- build submarine forests and their ecological role is crucial in the marine ecosystems as a natural refuge for a wide range of organisms (algae, fish, molluscs, etc.).

Rafting to the South

As scientific news, the new study identified a potentially invasive species in the stranded algae in the Antarctic shore: the bryozoan Membranipora membranacea, a colonial organism believed to be from the northeast Pacific Ocean. According to researcher Blanca Figuerola (ICM-CSIC), "this species has never been previously reported from south of the Polar Front. Thus, it could have a big ecological impact on the biodiversity in Antarctica in the future. This species has a fast growth rate and could easily colonize a notable surface of kelp rafts, creating thick layers and making them more fragile. The colonies of M. membranacea limit the ability of algae to reproduce and grow and make them prone to break during storms, and this further facilitates the spread of the bryozoan".

"Moreover -continues Figuerola- the encrusting colonies can settle on other surfaces (plastics, boats, etc.), and plankton larvae can be transported by ballast water and survive during months. All these factors would affect the environmental balance should the species settle in Antarctica".

Antarctic Peninsula: a new area for biological invasions?

With global warming effects -higher temperatures and the fast ice melting in the planet- there are more and more sensitive areas to the arrival of non-native invasive species. These phenomena are especially worrying in areas such as the Antarctic Peninsula, where environmental conditions could favor the survival of the potentially invasive species.

"The Antarctic Peninsula is the most vulnerable area to the episodes of biological invasions through drifting waters. The geographical latitude, and closeness to terrestrial areas -South America, Scotia Arch islands, etc.- with potentially invasive species, the position of the coasts regarding the Antarctic Circumpolar Current, and the climate conditions are factors that would favor the arrival and colonizing success of non-native species carried by algae or plastics", notes Àvila, head of the research projects Bluebio, Distantcom, Ecoquim and Actiquim, on the ecology of marine invertebrate communities in Antarctic waters.

The risk of invasion by non-native species is high in volcanic areas -such as Deception Island- since its environmental conditions are more favorable. However, any coastal area without ice could be a potential area for algae to arrive and distribute these organisms.

"In the context of a global change, what occurs in the Antarctic Peninsula could take place as well in other areas of the White Continent. Also, some non-native and generalist species could reach the Antarctic environment and adapt to the new environmental conditions. This could have dramatic effects on the local organisms of the marine ecosystems", notes the researcher.

"The Antarctic is warming, presenting new opportunities, both caused by humans and natural, for animals and plants to enter Antarctic waters, changing the existing unique local communities forever. Our findings highlight how much easier than we previously thought it is for animals that have caused environmental damage elsewhere to reach the most extreme and remote continent on Earth. They are also a reminder that the ongoing work of scientists, in studying the biodiversity and ecology of the region, is vital in detecting these changes before these new species become established" concludes the expert Huw James Griffiths (British Antarctic Survey, BAS).

Antarctica: beyond biogeographical frontiers

Today, biogeographical frontiers that limit Antarctica are not impenetrable anymore for many organisms. Some bryozoans can get over the polar front and the Antarctic Circumpolar Current, biogeographical frontiers in extreme latitudes in the Austral Ocean, as stated in a previous study by the UB-IRBio team (Marine Environmental Research, 2017). More recent studies describe a polar scenario in which the Southern Ocean is not as isolated as thought, the biogeographical limits -winds, currents and polar fronts- are blurred and remote archipelagos -between 45º and 60º southern latitude- are key points for the expansion over the polar front.

The authors of the study warn that, in this situation of ecological and climate change, threatened by the effects of global change, research and monitoring natural ecosystems becomes more necessary to preserve biodiversity.

In a study probing the boundary between the classical and quantum worlds, researchers laser-cooled a tiny glass nanoparticle with the density of a solid object to a quantum state. The particle they cooled and manipulated, while quite small in itself, is millions of times larger and far more complex than the atomic-scale objects most often used to investigate quantum motion. The researchers' new method may allow for otherwise unachievable quantum manipulations of objects involving large masses and offers a promising new platform for studying macro-quantum physics more broadly. At quantum scales, matter behaves strangely; the physics we use to understand the physical properties of larger objects cease to be useful. Much of what we know about the quantum world has been observed in the smallest of the small - single atoms, molecules and ions, for example. The quantum control of larger, complex particles would allow unprecedented opportunities to test fundamental physics and probe the limits and boundaries between the worlds of classic and quantum mechanics. However, achieving such extreme quantum states in "macroscopic" solid-state particles presents a major challenge. Using lasers to optically levitate, ensnare and cool atoms has enabled the isolation and study of the quantum properties of individual atoms and quantum gasses. Using similar techniques, Uroš Deli? and colleagues trapped and suspended a solid-state 150-nanometer glass sphere containing 100 million atoms. Starting from room temperature, Deli? et al. laser-cooled the nanoparticle to its quantum ground state of motion - a temperature of roughly -273 degrees Celsius. According to the authors, their ability to optically levitate and control the particle facilitates a range of macroscopic quantum experiments.

Chestnut Hill, Mass. - Refugees from Bhutan and Somalia report high rates of approval for a new intervention program developed "for refugees, by refugees" to help strengthen immigrant families as they settle in the US, according to a new study by the Boston College team that developed and implemented the community-based initiative.

Members of the Massachusetts Bhutanese and Somali Bantu communities who participated in the project remained with the program at a rate of 82.5 percent, the researchers reported recently in the Journal of Adolescent Health. Among the Bhutanese and Somali Bantu caregivers supporting the new immigrants, 81.5 percent were satisfied with the initiative, known as the Family Strengthening Intervention for Refugees.

"What is important about this project is that it uses community-based, participatory research methods to identify community issues facing children and families," said Boston College School of Social Work Professor Theresa Betancourt, the lead researcher. "We worked collaboratively to adapt an evidence-based family strengthening intervention to the culture and context of Bhutanese and Somali Bantu refugees resettling in New England."

The researchers studied 80 families - half of them Bhutanese, half Somali Bantu - to assess the program, its acceptance and any trends in improving child mental health and family functioning. Nationwide, approximately 100,000 Bhutanese and approximately 10,000 Somali Bantu have settled in the U.S..

While resettlement can impact refugee mental health, there are few preventative interventions, especially when it comes to mental health and family functioning, said Betancourt, the Salem Professor in Global Practice and director of the Research Program on Children and Adversity at BC. "We set out to answer if a family-based, home-visiting, preventative intervention done for refugees, by refugees could be feasible, acceptable, and impactful on the wellbeing of youth and families."

In addition to the high rates of satisfaction and engagement, the study uncovered other important trends that bode well for its full implementation and evaluation of effectiveness. For instance, children in the study group reported less traumatic stress reactions. Parents and other caregivers reported fewer child depression symptoms, when compared to a control group of families who did not receive the intervention.

Bhutanese children reported less arguing among family members and fewer symptoms of depression. While caregivers noted improved child behavior among Somali Bantu children in the control group, they found families in the study group had fewer conduct problems compared to the control group, according to the journal article, titled Family-Based Mental Health Promotion for Somali Bantu and Bhutanese Refugees: Feasibility and Acceptability Trial.

Given the small number of participants, trends on its impact will be explored further in a planned long-term evaluation of the effectiveness of the program in a study involving 300 families.

Betancourt cautioned that until that effectiveness study is done, it is too early to draw sweeping conclusions about the intervention impact, particularly given the relatively small number of participants. But the early findings point to a program that is promising and can be successfully implemented in refugee communities by lay workers who receive strong training and ongoing supervision to support resettled families from refugee communities.

The researchers say the study results suggest the program can be used, with minor adaptations, to support immigrants from other countries.

"Overall we were very happy to see that an intervention delivered by refugees, for refugees could be acceptable and feasible even during these very difficult times when the national dialogue on refugees can be very negative," said Betancourt.

A study, led by the University of Liverpool and King's College London, has identified the reasons why UK serving and ex-serving military personnel drink, in research based on military personnel self-reporting a stress or emotional problem.

Alcohol misuse is common in the United Kingdom (UK) Armed Forces, at a higher prevalence than the general population. Alcohol has historically been used in the UK Armed Forces to encourage bonding and to deal with difficult experiences. And while alcohol use is now on the decline in both populations, alcohol misuse in the forces is still double that of the general population. To put this into perspective, about 10% of personnel in the UK Armed Forces meet the criteria for alcohol misuse, compared to just 3% of the UK general population.

Despite the high prevalence of alcohol misuse in this group, the reasons why people within the UK military drink have not been studied.

The researchers aimed to identify the reasons why UK military personnel drink and explored the characteristics of those who were drinking for different reasons. They also investigated if the context of drinking (i.e., where and who with) made them more or less likely to meet the criteria for alcohol misuse or binge drinking.

As part of the study, 707 serving and 572 ex-serving military personnel reporting a stress or mental health problem occurring in the last three years were selected from a large follow up study of UK military personnel. Researchers conducted a telephone interview to examine military personnel's mental health, alcohol use and reasons for drinking.

The majority of the sample were male (84%), with 18% of personnel meeting the criteria for alcohol misuse. When looking at how common mental health problems were, they found that 18% met the criteria for anxiety, 8% for depression and 8% for post-traumatic stress disorder (PTSD).

The reasons for drinking were categorised as either drinking to cope (such as, to escape your troubles or to forget your past) or drinking because of social pressure (such as, to fit in or to be sociable), in UK military personnel with a stress or emotional problem.

Those who met the criteria for depression, anxiety and PTSD were more likely to drink to cope, suggesting that they may be drinking to deal with the mental health symptoms.

Military personnel who reported drinking to cope were more likely to meet the criteria for alcohol misuse and binge drinking. Personnel who drink at home or alone were also more likely to meet the criteria for alcohol misuse and binge drinking.

However, the researchers state that these findings only reflect the reasons for drinking in military personnel who report having a stress or emotional problem, and may not be representative of the wider UK armed forces community.

Corresponding author, Patricia Irizar, PhD student at the University of Liverpool, said: "Amongst military personnel with a stress or emotional problem, those who drink to cope with mental disorder symptoms, in addition to those who drink at home or drink alone (rather than with friends/family), are more likely to drink excessively."

Lead author, Dr Laura Goodwin, Psychological Sciences, University of Liverpool, said: "This study identifies the need to better integrate mental health and substance use services for military personnel, who may be drinking to cope with an existing mental health problem."

Professor Nicola Fear, King's Centre for Military Health Research, King's College London, said: "These findings can inform the development of tailored alcohol interventions for this occupational group, by identifying individuals who use alcohol in a way that is more likely to become problematic."

The lens of the human eye comprises a highly concentrated protein solution, which lends the lens its great refractive power. Protective proteins prevent these proteins from clumping together throughout a lifetime. A team of scientists from the Technical University of Munich (TUM) has now uncovered the precise structure of the alpha-A-crystallin protein and, in the process, discovered an important additional function.

The refractive power of the human eye lens stems from a highly concentrated protein solution. These proteins are created during embryonic development and must then function for a whole life, as the lens has no machinery to synthesize or degrade proteins.

When lens proteins are damaged, the result is cataract - a clouding of the lens - or presbyopia. This is where protective proteins come in: They ensure that the proteins of the eye retain their form even under adverse environmental influences.

"The two protective proteins alpha-A and alpha-B-crystallin make up around 30 percent of the proteins in the human eye and are extremely important for the function of the lens," says Christoph Kaiser, first author of the publication in the journal Nature Structural and Molecular Biology.

Structure of a multifaceted protein

Attempts to determine the structure of alpha-A-crystallin were unsuccessful for over 40 years. The breakthrough came for a research team led by the TUM professors Sevil Weinkauf, professor of electron microscopy and Johannes Buchner, professor of biotechnology, by combining cryo-electron microscopy, mass spectrometry, NMR spectroscopy and molecular modeling.

"Alpha-A-crystallin is extremely multifaceted," says Sevil Weinkauf. "This makes it very difficult to determine its structure. It was only after developing a new strategy for data analysis that we were able to demonstrate that in solution it takes on different structures with 12, 16 or 20 subunits."

Protection against oxidation

The typical function of protective proteins is to help other proteins maintain their form when stressed, by high temperatures, for example. This is why they are also referred to as chaperones.

Alpha-A and alpha-B-crystallin, too, have this function. In addition, human alpha-A-crystallin has two cysteine residues. The sulfur atoms in these residues can form disulfide bridges. In-depth biochemical studies have shown that this bridging has a significant impact on various properties of the protein molecule.

"A common theory is that the disulfide bridges result from damage to the protein, for example through oxygen," says Johannes Buchner. "Our results suggest that alpha-A-crystallin might play an active role in protecting other proteins from oxidation."

Motivation for further research

The research team's investigations demonstrate that oxidized alpha-A-crystallin can even transfer the existing disulfide bridge to other proteins. "This ability corresponds to that of a protein disulfide oxidase," says Christoph Kaiser. "Alpha-A-crystallin can thus influence the redox state of other lens proteins. This function also explains why roughly half of the alpha-A-crystallins in embryos already have such disulfide bridges."

"Around 35 percent of all cases of blindness can be attributed to cataracts, says Sevil Weinkauf. "The molecular understanding of the functions of eye lens proteins forms an essential basis for developing prevention and therapy strategies. The realization that alpha-A-crystallin also plays an important role in protecting against oxidation will now spawn further research."

Graphene is a paradox. It is the thinnest material known to science, yet also one of the strongest. Now, research from University of Toronto Engineering shows that graphene is also highly resistant to fatigue -- able to withstand more than a billion cycles of high stress before it breaks.

Graphene resembles a sheet of interlocking hexagonal rings, similar to the pattern you might see in bathroom flooring tiles. At each corner is a single carbon atom bonded to its three nearest neighbours. While the sheet could extend laterally over any area, it is only one atom thick.

The intrinsic strength of graphene has been measured at more than 100 gigapascals, among the highest values recorded for any material. But materials don't always fail because the load exceeds their maximum strength. Stresses that are small but repetitive can weaken materials by causing microscopic dislocations and fractures that slowly accumulate over time, a process known as fatigue.

"To understand fatigue, imagine bending a metal spoon," says Professor Tobin Filleter, one of the senior authors of the study, which was recently published in Nature Materials. "The first time you bend it, it just deforms. But if you keep working it back and forth, eventually it's going to break in two."

The research team -- consisting of Filleter, fellow University of Toronto Engineering professors Chandra Veer Singh and Yu Sun, their students, and collaborators at Rice University -- wanted to know how graphene would stand up to repeated stresses. Their approach included both physical experiments and computer simulations.

"In our atomistic simulations, we found that cyclic loading can lead to irreversible bond reconfigurations in the graphene lattice, causing catastrophic failure on subsequent loading," says Singh, who along with postdoctoral fellow Sankha Mukherjee led the modelling portion of the study. "This is unusual behaviour in that while the bonds change, there are no obvious cracks or dislocations, which would usually form in metals, until the moment of failure."

PhD candidate Teng Cui, who is co-supervised by Filleter and Sun, used the Toronto Nanofabrication Centre to build a physical device for the experiments. The design consisted of a silicon chip etched with half a million tiny holes only a few micrometres in diameter. The graphene sheet was stretched over these holes, like the head of a tiny drum.

Using an atomic force microscope, Cui then lowered a diamond-tipped probe into the hole to push on the graphene sheet, applying anywhere from 20 to 85 per cent of the force that he knew would break the material.

"We ran the cycles at a rate of 100,000 times per second," says Cui. "Even at 70 per cent of the maximum stress, the graphene didn't break for more than three hours, which works out to over a billion cycles. At lower stress levels, some of our trials ran for more than 17 hours."

As with the simulations, the graphene didn't accumulate cracks or other tell-tale signs of stress -- it either broke or it didn't.

"Unlike metals, there is no progressive damage during fatigue loading of graphene," says Sun. "Its failure is global and catastrophic, confirming simulation results."

The team also tested a related material, graphene oxide, which has small groups of atoms such as oxygen and hydrogen bonded to both the top and bottom of the sheet. Its fatigue behaviour was more like traditional materials, in that the failure was more progressive and localized. This suggests that the simple, regular structure of graphene is a major contributor to its unique properties.

"There are no other materials that have been studied under fatigue conditions that behave the way graphene does," says Filleter. "We're still working on some new theories to try and understand this."

In terms of commercial applications, Filleter says that graphene-containing composites -- mixtures of conventional plastic and graphene -- are already being produced and used in sports equipment such as tennis rackets and skis.

In the future, such materials may begin to be used in cars or in aircraft, where the emphasis on light and strong materials is driven by the need to reduce weight, improve fuel efficiency and enhance environmental performance.

"There have been some studies to suggest that graphene-containing composites offer improved resistance to fatigue, but until now, nobody had measured the fatigue behaviour of the underlying material," he says. "Our goal in doing this was to get at that fundamental understanding so that in the future, we'll be able to design composites that work even better."

Scientists have developed new way to break down plant-based plastics into their original building blocks, potentially allowing products to be recycled repeatedly without a loss in the quality of the plastic.

Around 45% of plastic waste is recycled annually in the UK and is on the increase. However one of the problems with current plastic recycling methods is that you end up with a lower quality plastic with worse properties than the original. This means that plastic drinks bottles cannot simply be recycled into new drinks bottles continuously, but instead are used for other lower grade products such as water pipes, park benches and traffic cones.

Now scientists from the Universities of Bath and Birmingham have developed a new way of chemical recycling - converting plastics back into their constituent chemical molecules - so that they can be used to make new plastics of the same quality as the original.

The team's method, published in ChemSusChem, uses lower temperatures and more environmentally-friendly catalysts than previous methods.

Professor Matthew Jones, from the Centre for Sustainable & Circular Technologies at the University of Bath, said: "Most plastic is currently recycled using mechanical methods, where they are chipped into granules and melted down before being moulded into something new.

"The problem is, melting plastic changes its properties, and reduces the quality, which limits the range of products in which it can be used.

"Our method of chemical recycling overcomes this problem by breaking down plastic polymers into their chemical building blocks, so they can be used all over again to make virgin plastic without losing any properties."

The researchers recycled plant-based PLA, which is made from starch or crop waste instead of petrochemicals, and is used in "biodegradable" food packaging and disposable cutlery and cups. PLA isn't currently recycled because it's not used widely yet, however with growing awareness of plastic pollution, the demand from consumers for recyclable packaging is growing.

The team has also started trialling a similar process for recycling PET, which is used for drinks bottles.

First author of the paper, Dr Paul McKeown from the University of Bath, said: "PLA is being increasingly used as a sustainable alternative for single-use plastics. Whilst it's biodegradable under industrial conditions, it doesn't biodegrade with home composting, and isn't currently recycled, so at the moment it commonly ends up contributing to the tonnes of plastic waste in landfill and oceans.

"There is no single solution to the problem of plastic waste - the approach has to be a combination of reducing, reusing and recycling. Our method of chemical recycling could allow carbon to be recycled indefinitely - creating a circular economy rather than digging more up from the ground in the form of fossil fuels, or releasing it into the atmosphere as a greenhouse gas."

So far, the technology has only been demonstrated on a small scale, however collaborators at the University of Birmingham are now working to scale up the system to produce larger quantities of starting chemicals.

What if solar cells worked at night? That's no joke, according to Jeremy Munday, professor in the Department of Electrical and Computer Engineering at UC Davis. In fact, a specially designed photovoltaic cell could generate up to 50 watts of power per square meter under ideal conditions at night, about a quarter of what a conventional solar panel can generate in daytime, according to a concept paper by Munday and graduate student Tristan Deppe. The article was published in, and featured on the cover of, the January 2020 issue of ACS Photonics.

Munday, who recently joined UC Davis from the University of Maryland, is developing prototypes of these nighttime solar cells that can generate small amounts of power. The researchers hope to improve the power output and efficiency of the devices.

Munday said that the process is similar to the way a normal solar cell works, but in reverse. An object that is hot compared to its surroundings will radiate heat as infrared light. A conventional solar cell is cool compared to the sun, so it absorbs light.

Space is really, really cold, so if you have a warm object and point it at the sky, it will radiate heat toward it. People have been using this phenomenon for nighttime cooling for hundreds of years. In the last five years, Munday said, there has been a lot of interest in devices that can do this during the daytime (by filtering out sunlight or pointing away from the sun).

Generating power by radiating heat

There's another kind of device called a thermoradiative cell that generates power by radiating heat to its surroundings. Researchers have explored using them to capture waste heat from engines.

"We were thinking, what if we took one of these devices and put it in a warm area and pointed it at the sky," Munday said.

This thermoradiative cell pointed at the night sky would emit infrared light because it is warmer than outer space.

"A regular solar cell generates power by absorbing sunlight, which causes a voltage to appear across the device and for current to flow. In these new devices, light is instead emitted and the current and voltage go in the opposite direction, but you still generate power," Munday said. "You have to use different materials, but the physics is the same."

The device would work during the day as well, if you took steps to either block direct sunlight or pointed it away from the sun. Because this new type of solar cell could potentially operate around the clock, it is an intriguing option to balance the power grid over the day-night cycle.

Flow rates and time of year must be taken into account to better understand the potential risks posed by emerging organic contaminants in rivers and streams, according to Penn State researchers who studied contaminant concentrations and flow characteristics at six locations near drinking water intakes in the Susquehanna River basin.

While many studies have looked at the levels of emerging organic contaminants such as pharmaceuticals and pesticides in rivers and their effect on aquatic life, this is one of the first projects to closely correlate pollutant levels with flows, noted researcher Heather Preisendanz, associate professor of agricultural and biological engineering.

In addition, the research team documented seasonal changes in contaminant concentrations, with elevated levels of some contaminants seen in the warmer months, posing the greatest risk to fish during their spawning and early developmental stages, said Preisendanz. Her research group in the College of Agricultural Sciences has been studying emerging contaminants in surface water and groundwater since 2013.

Researchers worked with the Pennsylvania-American Water Co. to sample the drinking water sources of six treatment plants -- three in the Susquehanna River, three in reservoirs -- all in the middle section of the Susquehanna River basin in central Pennsylvania.

During the two-phase study, scientists looked for contaminants previously detected in Pennsylvania waters. In Phase I, all water samples were analyzed bimonthly for seven human pharmaceutical compounds, including four antibiotics -- ampicillin, sulfamethoxazole, ofloxacin and trimethoprim; two analgesics -- acetaminophen and naproxen; and a stimulant -- caffeine. In Phase II, they conducted an intensive sampling regime at a single river site, focusing on a broader range of emerging organic contaminants.

In Phase I, sulfamethoxazole, acetaminophen and caffeine were most frequently detected, in 54%, 42% and 35% of the samples, respectively. Trimethoprim, naproxen, ofloxacin and ampicillin were detected in less than 35% of samples. Of the most frequently detected pharmaceuticals, caffeine had the highest average concentration, while sulfamethoxazole and acetaminophen had lower average concentrations. Ampicillin was the least frequently detected compound.

In Phase II, 13 more compounds were targeted for analysis, including human and veterinary antibiotics -- chlortetracycline, tetracycline, oxytetracycline, erythromycin, sulfadiazine, sulfadimethoxine, sulfamethazine, and tylosin; an antimicrobial -- triclosan; an antihistamine -- cimetidine; an antidiabetic -- metformin; a caffeine metabolite -- theobromine; and a neonicotinoid insecticide -- thiamethoxam.

In Phase II, the most frequently detected compounds were acetaminophen and theobromine -- both in 89% of samples -- caffeine, found in 87% of samples, and metformin in 84% of samples. Thiamethoxam, naproxen and sulfamethoxazole were detected in 21%, 17%, and 16% of samples, respectively. The other six compounds were detected in less than 2% of samples.

Concentrations of emerging organic compounds were low, but they were widespread, explained lead researcher Faith Kibuye, a doctoral candidate in the Department of Agricultural and Biological Engineering when the research was conducted.

"Overall, emerging organic contaminants were present at higher concentrations in colder seasons than warmer seasons. The concentration of thiamethoxam, a neonicotinoid insecticide, increased during high-flow periods," said Kibuye.

When flows were high, the levels of contaminants from nonpoint sources, most likely from agricultural runoff, were highest, and conversely, when flows were low, the concentrations of contaminants commonly found in sewage treatment plant discharges were highest, researchers found.

"This is because large storm events, particularly in the spring months, mobilize emerging contaminants, such as pesticides, from agricultural fields," Preisendanz said. "That explains the positive relationship between neonicotinoid concentrations and flow rate."

The picture was less clear for the contaminants that have both point and nonpoint sources, Preisendanz added, because some older municipalities have combined storm and sanitary sewer systems that discharge untreated sewage during high-flow events.

Even without water quality standards to define what levels might be considered safe for various aquatic organisms and human health, the researchers calculated risk assessments for compounds found in the study using exposure limits already set by the U.S. Food and Drug Administration. Those calculations revealed that although the compounds posed medium to high risk to aquatic organisms, human health risk from drinking water or consuming fish is low. However, the study's findings, recently published in Chemosphere, did not determine the risks due to the presence of multiple contaminants in the water simultaneously.

"We do not know the effect of being exposed to a cocktail of these compounds, even at low levels, and whether they might have a synergistic effect," Preisendanz said.

Despite an ever-rising number of pedestrian and bicyclist deaths on U.S. roads each year, there's no widespread public pressure to improve road safety -- a situation influenced by how news articles about auto-pedestrian/bicyclist crashes are written, said Tara Goddard, Texas A&M assistant professor of urban planning.

"Adopting simple improvements in crash reporting offers a potentially powerful tool to shift public awareness of traffic crashes from unfortunate, isolated events to a preventable public health issue," said Goddard in a paper describing the first-of-its-kind study she led with a team of Rutgers University planning and public policy scholars.

The study gauged perceptions of subjects who read articles about crashes with slight, but significant wording changes that changed the focus of the article from the pedestrian/victim to the car/driver.

It's the first study to demonstrate that patterns in crash reporting influence readers' interpretation of what happened and who bears responsibility for the crash.

"We found that shifting from pedestrian- to driver-focused language reduced victim-blaming and increased perceived blame for the driver," said Goddard.

In the articles, for example, "A pedestrian was hit and killed by a car" was changed to "A car hit and killed a pedestrian."

Another example: "A car jumped the curb" was changed to "A driver drove over the curb."

Still another example: "A pedestrian was hit and killed" was changed to "A pedestrian was hit and killed by a car."

"Given the potential to save lives and prevent injury on a large scale, implementing more intentional writing patterns may be nothing less than an ethical imperative," said Goddard, who led the study with Rutgers colleagues Kelcie Ralph, Calvin Thigpen and Evan Iacobucci.

Goddard's research focuses on "vulnerable" road user safety such as pedestrians and bicyclists, autonomous vehicle technology and driver behavior, auto driver cognition and attention, traffic safety and crash reduction, and sustainable transportation design.