Astronomers to release most accurate data ever for nearly two billion stars

 On 3 December an international team of astronomers will announce the most detailed ever catalogue of the stars in a huge swathe of our Milky Way galaxy. The measurements of stellar positions, movement, brightness and colours are in the third early data release from the European Space Agency's Gaia space observatory and will be publicly available. Initial findings include the first optical measurement of the acceleration of the Solar system. The data set, and early scientific discoveries, will be presented at a special briefing hosted by the Royal Astronomical Society.

Launched in 2013, Gaia operates in an orbit around the so-called Lagrange 2 (L2) point, located 1.5 million kilometres behind the Earth in the direction away from the Sun. At L2 the gravitational forces between the Earth and Sun are balanced, so the spacecraft stays in a stable position, allowing long-term essentially unobstructed views of the sky.

The primary objective of Gaia is measure stellar distances using the parallax method. In this case astronomers use the observatory to continuously scan the sky, measuring the apparent change in the positions of stars over time, resulting from the Earth's movement around the Sun.

Knowing that tiny shift in the positions of stars allows their distances to be calculated. On Earth this is made more difficult by the blurring of the Earth's atmosphere, but in space the measurements are only limited by the optics of the telescope.

Two previous releases included the positions of 1.6 billion stars. This release brings the total to just under 2 billion stars, whose positions are significantly more accurate than in the earlier data. Gaia also tracks the changing brightness and positions of the stars over time across the line of sight (their so-called proper motion), and by splitting their light into spectra, measures how fast they are moving towards or away from the Sun and assesses their chemical composition.

The new data include exceptionally accurate measurements of the 300,000 stars within the closest 326 light years to the Sun. The researchers use these data to predict how the star background will change in the next 1.6 million years. They also confirm that the Solar system is accelerating in its orbit around the Galaxy.

This acceleration is gentle, and is what would be expected from a system in a circular orbit. Over a year the Sun accelerates towards the centre of the Galaxy by 7 mm per second, compared with its speed along its orbit of about 230 kilometres a second.

Gaia data additionally deconstruct the two largest companion galaxies to the Milky Way, the Small and Large Magellanic Clouds, allowing researchers to see their different stellar populations. A dramatic visualisation shows these subsets, and the bridge of stars between the two systems.

Dr Floor van Leeuwen of the Institute of Astronomy at the University of Cambridge, and UK Gaia DPAC Project Manager, comments: "Gaia is measuring the distances of hundreds of millions of objects that are many thousands of light years away, at an accuracy equivalent to measuring the thickness of hair at a distance of more than 2000 kilometres. These data are one of the backbones of astrophysics, allowing us to forensically analyse our stellar neighbourhood, and tackle crucial questions about the origin and future of our Galaxy."

Read more at Science Daily

Scientists peer into the 3D structure of the Milky Way

 Scientists from Cardiff University have helped produce a brand-new, three-dimensional survey of our galaxy, allowing them to peer into the inner structure and observe its star-forming processes in unprecedented detail.

The large-scale survey, called SEDIGISM (Structure, Excitation and Dynamics of the Inner Galactic Interstellar Medium), has revealed a wide range of structures within the Milky Way, from individual star-forming clumps to giant molecular clouds and complexes, that will allow astronomers to start pushing the boundaries of what we know about the structure of our galaxy.

SEDIGISM has been unveiled today through the publication of three separate papers in the Monthly Notices of the Royal Astronomical Society, authored by an international team of over 50 astronomers.

"With the publication of this unprecedentedly detailed map of cold clouds in our Milky Way, a huge observational effort comes to fruition," says Frederic Schuller from the Max Planck Institute for Radio Astronomy (MPIfR), lead author of one of the three publications, presenting the data release.

Dr Ana Duarte Cabral, a Royal Society University Research Fellow from Cardiff University's School of Physics and Astronomy, was lead author on one of the papers and has provided a catalogue of over 10,000 clouds of molecular gas in our Milky Way.

The Milky Way, named after its hazy appearance from Earth, is a spiral galaxy with an estimated diameter between 170,000 and 200,000 light-years which contains between 100-400 billion stars.

The Milky Way consists of a core region that is surrounded by a warped disk of gas and dust that provides the raw materials from which new stars are formed.

For Dr Duarte Cabral, the new catalogue of gas clouds will allow scientists to probe exactly how the spiral structure of our own Milky Way affects the life cycle of clouds, their properties, and ultimately the star formation that goes on within them.

"What is most exciting about this survey is that it can really help pin down the global galactic structure of the Milky Way, providing an astounding 3D view of the inner galaxy," she said.

"With this survey we really have the ability to start pushing the boundaries of what we know about the global effects of the galactic structures and dynamics, in the distribution of molecular gas and star formation, because of the improved sensitivity, resolution, and the 3D view."

The catalogue of molecular gas clouds was created by measuring the rare isotope of the carbon monoxide molecule, 13CO, using the extremely sensitive 12-metre Atacama Pathfinder Experiment telescope on the Chajnantor plateau in Chile.

This allowed the team to produce more precise estimates of the mass of the gas clouds and discern information about their velocity, therefore providing a truly three-dimensional picture of the galaxy.

Dr Duarte Cabral and colleagues are already beginning to tease out information from the vast amount of data at their disposal.

"The survey revealed that only a small proportion, roughly 10%, of these clouds have dense gas with ongoing star formation," said James Urquhart from the University of Kent, the lead author of the third publication.

Similarly, the results from the work led by Dr Duarte Cabral suggest that the structure of the Milky Way is not that well defined and that the spiral arms are not that clear.

They have also shown that the properties of clouds do not seem to be dependent on whether a cloud is located in a spiral arm or an inter-arm region, where they expected very different physics to be playing a role.

"Our results are already showing us that the Milky Way may not be a strong grand design type of spiral galaxy as we thought, but perhaps more flocculent in nature," Dr Duarte Cabral continued.

Read more at Science Daily

Patients with heart rhythm disorder warned against heavy alcohol consumption

 Fourteen drinks a week is linked with a higher risk of health problems including stroke and embolism in patients with atrial fibrillation, according to research published in EP Europace, a journal of the European Society of Cardiology (ESC).

"Our study suggests that atrial fibrillation patients should avoid heavy alcohol consumption to prevent stroke and other complications," said author Dr. Boyoung Joung of Yonsei University College of Medicine, Seoul, Republic of Korea.

The study included 9,411 patients with atrial fibrillation from 18 tertiary hospitals covering all geographical regions of South Korea. Patients were categorised into four groups according to their weekly alcohol consumption (one drink contains 14 grams of alcohol): abstainer/rare (0 grams/less than one drink), light (less than 100 grams/7 drinks), moderate (100-200 grams/7-14 drinks), and heavy (200 grams/14 drinks or more).

A total of 7,455 (79.2%) patients were classified as abstainer/rare, 795 (8.4%) as light, 345 (3.7%) as moderate, and 816 (8.7%) as heavy alcohol consumption.

Patients were followed-up for a median of 17.4 months for adverse events, which included stroke, transient ischaemic attack, systemic embolism (a blood clot in a limb or organ), and hospitalisation for rate or rhythm control of atrial fibrillation or for heart failure management. The researchers recorded how many patients experienced any of these events and calculated the incident rate (number of events per 100 person-years). Incident rates were 6.73, 5.77, 6.44, and 9.65 in the abstainer/rare, light, moderate, and heavy drinkers, respectively.

The researchers compared the risk of adverse events in the light, moderate, and heavy drinkers to the abstainer/rare group. Heavy drinking was associated with a 32% increased risk compared with the abstainers and rare drinkers. No significant association was observed for light or moderate alcohol consumption.

Dr. Joung said: "Our study did not find any significant association between light or moderate drinking and complications. A significant deleterious relationship with heavy drinking was identified, suggesting that heavy alcohol consumption should be avoided."

Subgroup analyses showed that the impact of heavy drinking was more pronounced in patients with low stroke risk2 compared to those at moderate or high stroke risk. Similarly, heavy drinking was associated with a greater likelihood of unfavourable outcomes in patients without high blood pressure compared to those with high blood pressure. Higher risks were also observed in patients not using beta-blockers or antiplatelet medications compared to those taking the drugs.

Dr. Joung said: "The findings indicate that heavy drinking is particularly detrimental for atrial fibrillation patients who are considered less vulnerable to complications. Clinicians should ask patients about their alcohol consumption and take it into account when calculating their stroke risk."

Read more at Science Daily

The tree of cortical cell types describes the diversity of neurons in the brain

The tree of life describes the evolution of life and seeks to define the relationships between species. Likewise, the tree of cell types aims to organize cells in the brain into groups and describe their relationships to each other.

Scientists have long pondered just what the brain's tree of cell types looks like. Now, an international collaboration led by Dr. Andreas Tolias from Baylor College of Medicine, Dr. Philipp Berens from the University of Tübingen in Germany and Dr. Rickard Sandberg from the Karolinska Institute in Stockholm, Sweden, has published an article in Nature that provides one of the most detailed and complete characterizations of the diversity of neural types in the brain so far.

Uncovering the shape of the tree of cortical cell types with Patch-seq

Neuroscientists mostly use three fundamental features to describe neurons: their anatomy, or how they look under a microscope; their physiology, or how they respond when stimulated; and, more recently, the genes they express, which are known as their transcriptome.

For this study, the research team used an experimentally challenging technique that they developed several years ago, called Patch-seq. This technique allowed them to collect a large multimodal database including genetic, anatomical and physiological information from single cells in the mouse motor cortex.

"Gathering all these three fundamental features from the same set of neurons was the key that enabled us to get a much deeper understanding of how neurons in the motor cortex are related to each other and a clearer view of how the tree of cell types looks like," said co-first author Dr. Federico Scala, postdoctoral associate in Tolias lab at Baylor.

Dr. Dmitry Kobak, also co-first author and a research scientist in Berens lab, described that while the broad genetic families of neurons had distinct anatomical and physiological properties, within each family the neurons exhibited extensive anatomical and physiological diversity. Importantly, all the three basic neuronal characteristics (anatomy, physiology and transcriptome) were correlated, which enabled the team to find interesting links between them.

"Our data supports the view that the tree of cortical cell types may look more like a banana tree with few big leaves rather than an olive tree with many small ones. This view provides a simpler model to describe the diversity of neurons we find in the brain. We believe that this simpler view will lead to a more principled understanding of why we have so many cell types in the brain to begin with and what they are used for," said Tolias, Brown Foundation Endowed Chair of Neuroscience and director of the Center for Neuroscience and Artificial Intelligence at Baylor.

Read more at Science Daily

Greenland ice sheet faces irreversible melting

 

Illustration of northern Canada and Greenland from space.

In a study published this week in The Cryosphere, researchers from the National Centre for Atmospheric Science and University of Reading demonstrate how climate change could lead to irreversible sea level rise as temperatures continue to rise and the Greenland ice sheet continues to decline.

The massive ice sheet faces a point of no return, beyond which it will no longer fully regrow, permanently changing sea levels around the world.

The Greenland ice sheet is seven times the area of the UK, and stores a large amount of the Earth's frozen water. At current rates of melting, it contributes almost 1mm to sea level per year, and accounts for around a quarter of total sea level rise.

Since 2003, despite seasonal periods of growth, Greenland's ice sheet has lost three and a half trillion tonnes of ice.

Rising sea levels are one of the most severe effects of climate change, threatening coastal areas around the world, and putting millions of people who live in low-lying areas at risk. Bangladesh, Florida, and eastern England are among many areas known to be particularly vulnerable.

Under scenarios in which global warming goes beyond 2°C, the Paris Agreement target, we should expect significant ice loss and several metres of global sea level rise to persist for tens of thousands of years, according to the new research. The warmer the climate, the greater the sea-level rise.

In addition, even if temperatures later return to current levels, scientists have shown that the Greenland ice sheet will never fully regrow once it melts beyond a critical point. After that point, sea levels would permanently remain two meters higher than now, regardless of other factors contributing to sea level rise.

This is because the ice sheet is so large that it has a substantial impact on its local climate, and as it declines, Greenland would experience warmer temperatures and less snowfall.

Once the ice-sheet retreats from the Northern part of the island, the area would remain ice-free.

To avoid the irreversible sea level rise the melting would cause, scientists say that climate change must be reversed before the ice sheet has declined to the threshold mass, which would be reached in about 600 years at the highest rate of mass loss within the likely range of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

Professor Jonathan Gregory, Climate Scientist from the National Centre for Atmospheric Science and University of Reading, said: "Our experiments underline the importance of mitigating global temperature rise. To avoid partially irreversible loss of the ice sheet, climate change must be reversed -- not just stabilised -- before we reach the critical point where the ice sheet has declined too far."

To study the ice-sheet, scientists from the National Centre for Atmospheric Science simulated the effects of Greenland ice sheet melting under a range of possible temperature rises, ranging from minimal warming to worst-case scenarios.

Under all future climates like the present or warmer, the ice-sheet declined in size and contributed to some degree of sea-level rise.

Importantly, there were scenarios in which the ice sheet melting could be reversed. But, they rely on actions to counteract global warming before it's too late.

Read more at Science Daily

A hint of new physics in polarized radiation from the early universe

 

Milky Way galaxy in the night sky.

Using Planck data from the cosmic microwave background radiation, an international team of researchers has observed a hint of new physics. The team developed a new method to measure the polarization angle of the ancient light by calibrating it with dust emission from our own Milky Way.

While the signal is not detected with enough precision to draw definite conclusions, it may suggest that dark matter or dark energy causes a violation of the so-called "parity symmetry."

The laws of physics governing the Universe are thought not to change when flipped around in a mirror. For example, electromagnetism works the same regardless of whether you are in the original system, or in a mirrored system in which all spatial coordinates have been flipped.

If this symmetry, called "parity," is violated, it may hold the key to understanding the elusive nature of dark matter and dark energy, which occupy 25 and 70 percent of the energy budget of the Universe today, respectively. While both dark, these two components have opposite effects on the evolution of the Universe: dark matter attracts, while dark energy causes the Universe to expand ever faster.

A new study, including researchers from the Institute of Particle and Nuclear Studies (IPNS) at the High Energy Accelerator Research Organization (KEK), the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) of the University of Tokyo, and the Max Planck Institute for Astrophysics (MPA), reports on a tantalizing hint of new physics -- with 99.2 percent confidence level -- which violates parity symmetry.

Their findings were published in the journal Physical Review Letters on November 23, 2020.

The hint to a violation of parity symmetry was found in the cosmic microwave background radiation, the remnant light of the Big Bang. The key is the polarized light of the cosmic microwave background. Light is a propagating electromagnetic wave. When it consists of waves oscillating in a preferred direction, physicists call it "polarized." The polarization arises when the light is scattered.

Sunlight, for instance, consists of waves with all possible oscillating directions; thus, it is not polarized. The light of a rainbow, meanwhile, is polarized because the sunlight is scattered by water droplets in the atmosphere. Similarly, the light of the cosmic microwave background initially became polarized when scattered by electrons 400,000 years after the Big Bang. As this light traveled through the Universe for 13.8 billion years, the interaction of the cosmic microwave background with dark matter or dark energy could cause the plane of polarization to rotate by an angle.

"If dark matter or dark energy interact with the light of the cosmic microwave background in a way that violates parity symmetry, we can find its signature in the polarization data," points out Yuto Minami, a postdoctoral fellow at IPNS, KEK.

To measure the rotation angle, the scientists needed polarization-sensitive detectors, such as those onboard the Planck satellite of the European Space Agency (ESA). And they needed to know how the polarization-sensitive detectors are oriented relative to the sky. If this information was not known with sufficient precision, the measured polarization plane would appear to be rotated artificially, creating a false signal.

In the past, uncertainties over the artificial rotation introduced by the detectors themselves limited the measurement accuracy of the cosmic polarization angle.

"We developed a new method to determine the artificial rotation using the polarized light emitted by dust in our Milky Way," said Minami. "With this method, we have achieved a precision that is twice that of the previous work, and are finally able to measure the (polarization angle)."

The distance traveled by the light from dust within the Milky Way is much shorter than that of the cosmic microwave background. This means that the dust emission is not affected by dark matter or dark energy, i.e. (the polarization angle) is present only in the light of the cosmic microwave background, while the artificial rotation affects both. The difference in the measured polarization angle between both sources of light can thus be used to measure (the angle).

The research team applied the new method to measure (the angle) from the polarization data taken by the Planck satellite. They found a hint for violation of parity symmetry with 99.2 percent confidence level. To claim a discovery of new physics, much greater statistical significance, or a confidence level of 99.99995 percent, is required.

Eiichiro Komatsu, director at the MPA and Principal Investigator at the Kavli IPMU, said: "It is clear that we have not found definitive evidence for new physics yet; higher statistical significance is needed to confirm this signal. But we are excited because our new method finally allowed us to make this 'impossible' measurement, which may point to new physics."

Read more at Science Daily

Fingerprints' moisture-regulating mechanism strengthens human touch

 

Fingerprint ridges close-up.

Human fingerprints have a self-regulating moisture mechanism that not only helps us to avoid dropping our smartphone, but could help scientists to develop better prosthetic limbs, robotic equipment and virtual reality environments, a new study reveals.

Primates -- including humans, monkeys and apes -- have evolved epidermal ridges on their hands and feet with a higher density of sweat glands than elsewhere on their bodies. This allows precise regulation of skin moisture to give greater levels of grip when manipulating objects.

Fingerprints help to increase friction when in contact with smooth surfaces, boost grip on rough surfaces and enhance tactile sensitivity. Their moisture-regulating mechanism ensures the best possible hydration of the skin's keratin layer to maximise friction.

Researchers at the University of Birmingham worked with partners at research institutions in South Korea, including Seoul National University and Yonsei University -- publishing their findings today in Proceedings of the National Academy of Sciences (PNAS).

Co-author Mike Adams, Professor in Product Engineering and Manufacturing, at the University of Birmingham commented: "Primates have evolved epidermal ridges on their hands and feet. During contact with solid objects, fingerprint ridges are important for grip and precision manipulation. They regulate moisture levels from external sources or the sweat pores so that friction is maximised and we avoid 'catastrophic' slip and keep hold of that smartphone."

"Understanding the influence of finger pad friction will help us to develop more realistic tactile sensors -- for example, applications in robotics and prosthetics and haptic feedback systems for touch screens and virtual reality environments."

Ultrasonic lubrication is commonly used in touch screen displays that provide sensory 'haptic' feedback, but its effectiveness is reduced when a user has dry compared with moist finger pads. Moreover, being able to distinguish between fine-textured surfaces, such as textiles, by touch relies on the induced lateral vibrations but the absence of sliding friction inhibits our ability to identify what we are actually touching.

Fingerprints are unique to primates and koalas -- appearing to have the dual function of enhancing evaporation of excess moisture whist providing a reservoir of moisture at their bases that enables grip to be maximised.

The researchers have discovered that, when finger pads are in contact with impermeable surfaces, the sweat from pores in the ridges makes the skin softer and thus dramatically increases friction. However, the resulting increase in the compliance of the ridges causes the sweat pores eventually to become blocked and hence prevents excessive moisture that would reduce our ability to grip objects.

Using hi-tech laser-based imaging technology, the scientists found that moisture regulation could be explained by the combination of this sweat pore blocking and the accelerated evaporation of excessive moisture from external wetting as a result of the specific cross-sectional shape of the epidermal furrows when in contact with an object.

These two functions result in maintaining the optimum amount of moisture in the fingerprint ridges that maximises friction whether the finger pad is initially wet or dry.

Read more at Science Daily

Researchers determine how the SARS-CoV-2 virus hijacks and rapidly causes damage to human lung cells

 

Illustration of SARS-CoV-2 viruses infecting human lung cells.

In a multi-group collaborative involving the National Emerging Infectious Disease Laboratories (NEIDL), the Center for Regenerative Medicine (CReM), and the Center for Network Systems Biology (CNSB), scientists have reported the first map of the molecular responses of human lung cells to infection by SARS-CoV-2. By combining bioengineered human alveolar cells with sophisticated, highly precise mass spectrometry technology, Boston University School of Medicine (BUSM) researchers have identified host proteins and pathways in lung cells whose levels change upon infection by the SARS-CoV-2, providing insights into disease pathology and new therapeutic targets to block COVID-19.

They found a crucial type of protein modification called "phosphorylation" becomes aberrant in these infected lung cells. Phosphorylation of proteins play a major role in regulating protein function inside the cells of an organism and both protein abundance and protein phosphorylation are typically highly controlled processes in the case of normal/healthy cells. However, they discovered that SARS-CoV-2 throws the lung cells into disarray, causing abnormal changes in protein amounts and frequency of protein phosphorylation inside these cells. These abnormal changes help the virus to multiply eventually destroy the cells. The destruction of infected cells may result in widespread lung injury.

According to the researchers, as soon as the SARS-CoV-2 enters the lung cells, it rapidly begins to exploit the cell's core resources, which are otherwise required for the cell's normal growth and function. "The virus uses these resources to proliferate while evading attack by the body's immune system. In this way new viruses form which subsequently exit the exhausted and brutally damaged lung cell, leaving them to self-destruct. These new viruses then infect other cells, where the same cycle is repeated," explains corresponding author Andrew Emili, PhD, professor of biochemistry at BUSM.

The researchers examined lung alveolar cells from one to 24 hours after infection with SARS-CoV-2 to understand what changes occur in lung cells immediately (at one, three and six hours after infection by SARS-CoV-2) and what changes occur later (at 24 hours after infection). These changes were then compared to uninfected cells. All proteins from infected and uninfected alveolar cells, corresponding to the different time-points were extracted and labelled with unique barcoding tags called "tandem mass tag." These tags, which can be accurately detected only by a mass spectrometer, permit robust quantification of protein and phosphorylation abundance in cells.

"Our results showed that in comparison to normal/uninfected lung cells, SARS-CoV-2 infected lung cells showed dramatic changes in the abundance of thousands of proteins and phosphorylation events," said Darrell Kotton, MD, professor of pathology & laboratory medicine at BUSM and director of the CReM.

"Moreover, our data also showed that the SARS-CoV-2 virus induces a significant number of these changes as early as one hour post infection and lays the foundation for a complete hijack of the host lung cells," adds Elke M?hlberger, PhD, associate professor of microbiology and principal investigator at the NEIDL.

"There are important biological features specific to lung cells that are not reproduced by other cell types commonly used to study viral infection," said Andrew Wilson, MD, associate professor of medicine at BUSM and CReM investigator. "Studying the virus in the context of the cell type that is most damaged in patients is likely to yield insights that we wouldn't be able to see in other model systems."

The researchers also analyzed their data to identify prospective opportunities for COVID-19 treatment and found that at least 18 pre-existing clinically approved drugs (developed originally for other medical conditions/diseases) can be potentially re-purposed for use towards COVID-19 therapy. These drugs have shown exceptional promise to block the proliferation of the SARS-CoV-2 in lung cells.

The researchers believe this information is invaluable and paves the way for newer, potentially promising and more importantly, a cost-effective and time-saving therapeutic strategy to combat COVID-19.

Read more at Science Daily

Experiments unravelling the mystery of Mars' moon Phobos

 Of course, there is no weather in our sense of the word in space -- nevertheless, soil can also "weather" in the vacuum of space if it is constantly bombarded by high-energy particles, such as those emitted by the sun. The Martian moon Phobos is affected by a special situation: it is so close to Mars that not only the solar wind but also the irradiation by particles from Mars plays a decisive role there. A research team from TU Wien has now been able to measure this in laboratory experiments. In just a few years, a Japanese space mission will take soil samples from Phobos and bring them back to Earth.

Billions of years of particle irradiation

"There are different theories of how the Mars moon Phobos could have formed," says Paul Szabo, who is working on his PhD thesis in the research group of Prof. Friedrich Aumayr at the Institute of Applied Physics at TU Wien. "It is possible that Phobos was originally an asteroid that was then captured by Mars, but it could also have been created by a collision of Mars with another large object."

When investigating such celestial bodies, one must always bear in mind that their surfaces have been completely changed over billions of years by cosmic particle bombardment. The surface of the Earth remains unaffected by this, because our atmosphere shields the particles. However, the geology of celestial bodies without atmospheres, such as our Moon or Phobos, can only be understood if it is possible to correctly assess "space weathering."

Therefore, elaborate experiments were conducted at TU Wien: "We used a mineral like it is found on Phobos and bombarded it in vacuum chambers with different charged particles," explains Paul Szabo. "Using an extremely precise balance, we can measure how much material is removed in the process and how much each particle affects the surface.

The special properties of the moon Phobos must be taken into account: Its distance from the surface of Mars is less than 6000 km -- not even two percent of the distance between our Moon and the Earth. Just like our Moon, it is in a tidally locked rotation around its planet: The same side always faces Mars.

"Because of the extremely small distance between Mars and Phobos, not only particles emitted from the Sun play a role on the surface of Phobos, but also particles from Mars," says Paul Szabo. The Martian atmosphere consists mainly of carbon dioxide. But in the outer regions of the atmosphere there are also larger amounts of oxygen. When particles from the solar wind penetrate there, oxygen ions can be created, which then hit Phobos at high speed and change the surface material.

Data for 2024 space mission

"With our measuring methods we were able to estimate the erosion of Phobos much more accurately than was previously possible," says Friedrich Aumayr. "Our results show that the effect of oxygen ions from the Martian atmosphere cannot be neglected. It is also important to distinguish between the two sides of Phobos: While the solar wind causes the weathering on the side facing away from Mars, the bombardment from the Martian atmosphere dominates on the other side, when the Sun is shielded from Mars.

Read more at Science Daily

Breaking the rules of chemistry unlocks new reaction

 Scientists have broken the rules of enzyme engineering to unlock a new method for creating chemical reactions that could unlock a wide range of new applications -- from creating new drugs to food production.

In their paper published today in Nature Catalysis, Professor Francesca Paradisi and Dr. Martina Contente of the University of Nottingham and the University of Bern show a new method to produce chemical molecules more efficiently through a new one step reaction in the enzyme.

Professor Paradis is Professor of Biocatalysis in the School of Chemistry in Nottingham and Professor of Pharmaceutical Chemistry at the University of Bern, she explains: "We have demonstrated how a very simple mutation in one of the key residues of a useful enzyme has dramatically expanded its synthetic scope, enabling the use of the mutant variant in the preparation of challenging chemical molecules, as well as natural metabolites that are vital in many biological processes in the body."

Any textbook on enzymes will report on how the catalytic amino acids in any given enzyme family are highly conserved, they are in fact a signature of the type of chemistry an enzyme can do. Variations do occur and in some cases, if the replacing amino acid is similar, both can be found in significant proportion in Nature, but others can be much less common and are found only in a limited number of species.

"In this study we have explored an untouched area of enzyme engineering and modified the a key catalytic residue in the active site of an enzyme" adds Professor Paradisi, "Previously it was thought that doing this would cause a loss of activity of the enzyme but we have found this is not the case when this biocatalyst is used in a synthetic direction and in fact challenging but very useful molecules can now be made under mild conditions which could be easily scaled up and replicated commercially for use in a wide range of products."

To change the substrate scope of an enzyme the approach has generally been to mutate the residues involved in substrate recognition, whether through rational design or directed evolution, leaving always untouched the catalytic ones.

The mutant variant of an acyl transferase enzyme was rapidly created and while the native biocatalyst would work with alcohols and linear amines, the mutant work with thiols and much more complex amines too. The research demonstrated that indeed the new variant has lost the ability to hydrolyse esters, but for synthetic applications, where an ester or other functional groups need to be made (thioesters and amides) and not cleaved, this is in fact a major advantage.

Read more at Science Daily