How Do Greenhouse Gases Actually Work?

Chandra X-ray Observatory identifies new stellar danger to planets

Astronomers using data from NASA's Chandra X-ray Observatory and other telescopes have identified a new threat to life on planets like Earth: a phase during which intense X-rays from exploded stars can affect planets over 100 light-years away. This result has implication for the study of exoplanets and their habitability.

This newly found threat comes from a supernova's blast wave striking dense gas surrounding the exploded star. When this impact occurs it can produce a large dose of X-rays that reaches an Earth-like planet months to years after the explosion and may last for decades. Such intense exposure may trigger an extinction event on the planet.

A new study reporting this threat is based on X-ray observations of 31 supernovae and their aftermath—mostly from NASA's Chandra X-ray Observatory, Swift and NuSTAR missions, and ESA's XMM-Newton—show that planets can be subjected to lethal doses of radiation located as much as about 160 light-years away. Four of the supernovae in the study (SN 1979C, SN 1987A, SN 2010jl, and SN 1994I) are shown in composite images containing Chandra data in the supplemental image.

If a torrent of X-rays sweeps over a nearby planet, the radiation could severely alter the planet's atmospheric chemistry. For an Earth-like planet, this process could wipe out a significant portion of ozone, which ultimately protects life from the dangerous ultraviolet radiation of its host star. It could also lead to the demise of a wide range of organisms, especially marine ones at the foundation of the food chain, leading to an extinction event.

 Ian R. Brunton et al, X-Ray-luminous Supernovae: Threats to Terrestrial Biospheres, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/acc728

How electricity can heal wounds three times faster

Chronic wounds are a major health problem for diabetic patients and the elderly—in extreme cases they can even lead to amputation. Using electric stimulation, researchers have developed a method that speeds up the healing process, making wounds heal three times faster.

For most people, a small wound does not lead to any serious complications, but many common diagnoses make wound healing far more difficult. People with diabetes, spinal injuries or poor blood circulation have impaired wound healing ability. This means a greater risk of infection and chronic wounds—which in the long run can lead to such serious consequences as amputation.

Electric guidance of cells for faster healing
The researchers worked from an old hypothesis that electric stimulation of damaged skin can be used to heal wounds. The idea is that skin cells are electrotactic, which means that they directionally "migrate" in electric fields. This means that if an electric field is placed in a petri dish with skin cells, the cells stop moving randomly and start moving in the same direction.

The researchers investigated how this principle can be used to electrically guide the cells in order to make wounds heal faster. Using a tiny engineered chip, the researchers were able to compare wound healing in artificial skin, stimulating one wound with electricity and letting one heal without electricity. The differences were striking.

Researchers were able to show that the old hypothesis about electric stimulation can be used to make wounds heal significantly faster. In order to study exactly how this works for wounds, they developed a kind of biochip on which they cultured skin cells, which they then made tiny wounds in. Then they stimulated one wound with an electric field, which clearly led to it healing three times as fast as the wound that healed without electric stimulation.

In the study, the researchers also focused on wound healing in connection with diabetes, a growing health problem worldwide. One in 11 adults today has some form of diabetes according to the World Health Organization (WHO) and the International Diabetes Federation.

The researchers have also looked at diabetes models of wounds and investigated whether this method could be effective even in those cases. They saw that when they mimicked diabetes in the cells, the wounds on the chip healed very slowly. However, with electric stimulation they could increase the speed of healing so that the diabetes-affected cells almost corresponded to healthy skin cells.

Sebastian Shaner, Anna Savelyeva, Anja Kvartuh, Nicole Jedrusik, Lukas Matter, José Leal, Maria Asplund. Bioelectronic microfluidic wound healing: a platform for investigating direct current stimulation of injured cell collectives. Lab on a Chip, 2023; 23 (6): 1531 DOI: 10.1039/D2LC01045C

Mosquito Saliva Can Actually Suppress Our Immune System, Study Finds

We know mosquitoes are a serious threat to our health as human beings– in fact, they're the world's deadliest animal, with mosquito-borne diseases responsible for more than a million deaths a year.

And it's not just their bites that we need to worry about. New research shows how the saliva of a mosquito carrying the  dengue virus is loaded with a substance that may suppress our immune system response and increase the risk of infection.

Through three separate analysis methods, scientists identified a specific type of viral RNA, or chemical messenger, called sfRNA in the infected mosquito saliva. It essentially blocks the defense mechanisms the human body puts up against infection.

It's incredible that the virus can hijack these molecules so that their co-delivery at the mosquito bite site gives it an advantage in establishing an infection.

These findings provide new perspectives on how we can counteract dengue virus infections from the very first bite of the mosquito.

The sfRNA is loaded in membrane compartments called extracellular vesicles, ready for delivery. The dengue virus appears to "subvert mosquito biology", in the words of the researchers, to give it a better chance of spreading. In tests on immortalized cell lines, the team confirmed that this sfRNA payload did indeed increase virus infection levels – laying the groundwork so that the human body isn't quite so well prepared for attack. These sfRNAs have been spotted before in insect-borne viruses, including Zika and yellow fever. Their role, more generally, seems to be to get in the way of the chemical signaling used by the body as the virus replicates.

Right now, there's no way of treating the virus, only methods for managing the symptoms. While we're still some way from a drug to treat dengue, understanding more about it and how it spreads is essential in fighting it.

https://journals.plos.org/plospathogens/article?id=10.1371/journal....

A First-of-Its-Kind Signal Has Been Detected in The Human Brain

Scientists have recently identified a unique form of cell messaging occurring in the human brain that's not been seen before.

Excitingly, the discovery hints that our brains might be even more powerful units of computation than we realized.

In 2020, researchers  reported a mechanism in the brain's outer cortical cells that produces a novel 'graded' signal all on its own, one that could provide individual neurons with another way to carry out their logical functions.

By measuring the electrical activity in sections of tissue removed during surgery on epileptic patients and analyzing their structure using fluorescent microscopy, the neurologists found individual cells in the cortex used not just the usual sodium ions to 'fire', but calcium as well.

This combination of positively charged ions kicked off waves of voltage that had never been seen before, referred to as a calcium-mediated dendritic action potentials, or dCaAPs.

Brains – especially those of the human variety – are often compared to computers. The analogy has its limits, but on some levels they perform tasks in similar ways.

Both use the power of an electrical voltage to carry out various operations. In computers it's in the form of a rather simple flow of electrons through intersections called transistors.

In neurons, the signal is in the form of a wave of opening and closing channels that exchange charged particles such as sodium, chloride, and potassium. This pulse of flowing ions is called an action potential.

Instead of transistors, neurons manage these messages chemically at the end of branches called dendrites.

"The dendrites are central to understanding the brain because they are at the core of what determines the computational power of single neurons.

Part 1

Dendrites are the traffic lights of our nervous system. If an action potential is significant enough, it can be passed on to other nerves, which can block or pass on the message.

This is the logical underpinnings of our brain – ripples of voltage that can be communicated collectively in two forms: either an AND message (if x and y are triggered, the message is passed on); or an OR message (if x or y is triggered, the message is passed on).

Arguably, nowhere is this more complex than in the dense, wrinkled outer section of the human central nervous system; the cerebral cortex. The deeper second and third layers are especially thick, packed with branches that carry out high order functions we associate with sensation, thought, and motor control.

It was tissues from these layers that the researchers took a close look at, hooking up cells to a device called a somatodendritic patch clamp to send active potentials up and down each neuron, recording their signals.

There was a 'eureka' moment when  scientists saw the dendritic action potentials for the first time.

To ensure any discoveries weren't unique to people with epilepsy, they double checked their results in a handful of samples taken from brain tumors.

While the team had carried out similar experiments on rats, the kinds of signals they observed buzzing through the human cells were very different.

More importantly, when they dosed the cells with a sodium channel blocker called tetrodotoxin, they still found a signal. Only by blocking calcium did all fall quiet.

Finding an action-potential mediated by calcium is interesting enough. But modelling the way this sensitive new kind of signal worked in the cortex revealed a surprise.

In addition to the logical AND and OR-type functions, these individual neurons could act as 'exclusive' OR (XOR) intersections, which only permit a signal when another signal is graded in a particular fashion.

More work needs to be done to see how dCaAPs behave across entire neurons, and in a living system. Not to mention whether it's a human-thing, or if similar mechanisms have evolved elsewhere in the animal kingdom.

https://www.science.org/doi/10.1126/science.aax6239

Part 2

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Stuck stem cells cause grey hair

Hair turns grey when melanocyte stem cells in the hair follicle fail to mature into thei... — at least that’s true in mice, and humans have similar cells. Scientists had thought that hair greys because the follicle runs out of melanocytes. A team tracked individual cells in mice over two years, which revealed that melanocytes travel up and down the hair follicle and switch back and forth between mature and young states. When the cells become stuck and stop making this journey, they stop receiving the signal to produce pigment.

Unlike embryonic stem cells, which develop into all sorts of different organs, adult stem cells have a more set path. The melanocyte stem cells in our hair follicles are responsible for producing and maintaining the pigment in our hair.

Each hair follicle keeps immature melanocyte stem cells in storage. When they’re needed, those cells travel from one part of the follicle to another, where proteins spur them to mature into pigment-producing cells, giving hair its hue.

Scientists assumed that gray hair was the result of that pool of melanocyte stem cells running dry. However, previous studies with mice made  scientists wonder if hair could lose its pigment even when stem cells are still present.

To learn more about stem cell behavior throughout different phases of hair growth, the researchers spent two years tracking and imaging individual cells in mouse fur. To their amazement, the stem cells traveled back and forth within the hair follicle, transitioning into their mature, pigment-producing state and then out of it again.

But as time wore on, the melanocyte cells couldn’t keep up the double act. A hair falling out and growing back takes a toll on the follicle, and eventually, the stem cells stopped making their journey, and thus, stopped receiving protein signals to make pigment. From then on, the new hair growth didn’t get its dose of melanin.

The researchers further explored this effect by plucking hairs from mice, simulating a faster hair growth cycle. This “forced aging” led to a buildup of melanocyte stem cells stuck in their storage place, no longer producing melanin. The mice’s fur went from dark brown to salt-and-pepper.

While the study was conducted with rodents, the researchers say their findings should be relevant to how human hair gets and loses its color. What’s more, they hope their findings could be a step toward preventing or reversing the graying process.

https://www.nature.com/articles/s41586-023-05960-6.epdf?sharing_tok...

eHighway - solution for electrified road freight transport

It's not as difficult as you think to shout upwind, shows study

For years, people have been wondering why it feels so difficult to shout upwind. The sensation is common enough to have found its way into an idiom about not being understood. But a scientific explanation for the phenomenon is  - there wasn't been one!

A research team showed that our common sense understanding of this situation is wrong. It isn't harder to shout into the wind; it's just harder to hear yourself.

In fact, acousticians have long known that sound carries better within the first 100 meters upwind. Many people have noticed that a siren sounds louder as it approaches and then quieter as it moves away. The mechanics behind this is similar to the Doppler effect, in which a sound changes frequency as it moves.

Research had confirmed that wind doesn't affect the emanation pattern of speech, so there was no reason why shouting into the wind would be difficult.

Their results were surprising but simple: it's harder for people to hear themselves when shouting upwind.

When someone shouts upwind, their ears are situated downwind from their mouth, which means that their ears receive less sound—it's harder from them to hear their shout than when there's no wind.

The same thing happens when someone is moving quickly even if there's no wind blowing—if you're cycling, for example. As a person bikes, their motion generates a wind around their head even in stationary air, and they end up shouting because they can't hear their own voice well.

So be careful what you shout upwind, for others might hear you just fine, even if you don't. This information is particularly useful for people who work with sound, such as musicians.

Ville Pulkki et al, Perceived difficulty of upwind shouting is a misconception explained by convective attenuation effect, Scientific Reports (2023). DOI: 10.1038/s41598-023-32306-z

Using superconductors to move people, cargo and energy through one combined system

The promise of superconductivity for electrical power transmission and transportation has long been held back by high costs. Now researchers  have demonstrated a way to cut the cost and upend both the transit and energy transport sectors by using superconductors to move people, cargo and energy along existing highway infrastructure.

The combined system would not only lower the cost of operating each system but would also provide a way to store and transport liquified hydrogen, an important future source of clean energy. The liquified hydrogen would be used to cool the superconductor guideway as it is stored and transported, reducing the need for a separate specialized pipeline system capable of cooling the fuel to 20 degrees Kelvin, or minus 424 Fahrenheit. The concept, described in a paper published on April 24, 2023 in the journal APL Energy, suggests a future in which air travel and traditional freight transport could become obsolete, replaced by a "super system" allowing personal and commercial vehicles to travel at speeds up to 400 miles an hour—maybe even twice that fast.

Researchers built a model to demonstrate the key technical aspect of the concept—levitating a magnet above a superconductor guideway. Liquified nitrogen was used to cool the superconductors in the model; Researchers say future models will use hydrogen.

Vehicles with magnetized undercarriages—trains, cargo trucks, even personal vehicles—would enter the superconductor guideway, levitating and moving at high speed to reach their destinations. After leaving the guideway, vehicles would continue their trips powered by traditional electric or internal combustion motors.

People would be able to travel at their own convenience while enjoying the time-saving benefits of high-speed trains and air travel.

Fuel or electrical power consumption would drop dramatically while the car or truck was on the superconductor guideway, reducing both the cost and the environmental footprint.

Oleksii Vakaliuk et al, A multifunctional highway system incorporating superconductor levitated vehicles and liquefied hydrogen, APL Energy (2023). DOI: 10.1063/5.0139834. pubs.aip.org/aip/ape/article/1/1/016107/2884934

Population growth is the main driver of increased carbon emissions, study finds

The richest countries emit more carbon dioxide than the rest of the world combined, while population is only growing in the poorest countries. These are two widespread notions that argue for focusing on reducing emissions per capita in order to mitigate climate change. But this is not entirely true on the light of data from the last 30 years, new research published in the journal Sustainability shows.

A dominant narrative in the climate change debate is that addressing population is not relevant for mitigation. This is because the population is only growing in the poorest countries, whose contribution to global carbon emissions is negligible, the reasoning goes. The largest emissions come instead from rich countries where the population no longer grows.

"This way of reasoning is not correct. Our thorough analysis suggests that climate change mitigation strategies should address population along with per capita consumption and technological innovation. A comprehensive approach to the problem is needed," says Giangiacomo Bravo, professor at Linnaeus University.

Part 1

The World Bank's four income groups

The World Bank has four classifications of income for the world's countries: low, lower-middle, upper-middle and high income. These are based on the respective country's gross national income (GNI) per capita.

The current figures apply to the year 2021, when 28 countries are defined as low-income countries, 54 as lower-middle, 54 as upper-middle and 81 as high-income countries.

Analysis of 30 years of emission data

The basis for Giangiacomo Bravo's statement is the analysis of 30 years of emission data for all the world's countries that he and two research colleagues have carried out. By splitting the countries into four income groups according to the World Bank's standard classification, the researchers were able to confirm that the contribution of low-income countries to emission increase is indeed limited. However, they also found that:

• Population is growing in all four income groups.
• The largest contribution to global carbon emissions comes from the upper-middle group.
• Population growth is the main driver of increased emissions in all income groups except the upper-middle one.
• The successful reduction in per capita emissions that occurred in high-income countries was nullified by the parallel increase in population in the same group.

Part 2

"Our analysis does not support the widespread belief that increased affluence is the main driver of increased carbon emissions at the global level. It is definitely an important factor, but neglecting population growth leads to a skewed and misleading vision of reality."

"Developed nations with stable or declining populations should hence quit fighting these trends and instead embrace them. Just as a small population growth in rich countries can drive big emission increases, a population decrease in rich countries could have big emission-related benefits going forward," says Giangiacomo Bravo.

Study examines the potential of edible cutlery

Plastic waste is an increasing problem the world over, with food packaging and single-use items such as plastic knives and forks representing a significant component of the waste stream. There have been efforts to replace disposable cutlery with implements crafted from wood or bamboo, but work in the International Journal of Mathematical Modelling and Numerical Optimisation has looked at a radical alternative—edible cutlery.

Researchers think that creating edible cutlery from millet is one possibility. However, as they explain the production of such items from this unusual source material requires a lengthy step-by-step process.

the researchers recognized that such step-by-step processes lend themselves to being defined by a scientific queuing model that can be solved using supplementary variable queuing technology. They have thus developed a conceptual approach to queue theory that might be implemented in the creation of edible cutley and is displayed through a numerical and complex visual analysis.

Millet is a nutritious, gluten-free, and easily cultivable crop that is widely grown in many parts of the world, particularly in Africa and Asia. It is a general term for are small-grained, annual, warm-weather cereals in the grass family of crops. These plants are fast-growing and highly drought-tolerant. They could therefore be useful as a sustainable and accessible source material in the developing world.

If such edible cutlery were to become a sustainable alternative to plastic or wooden products, then there is a cradle-to-grave assessment to be made of energy and resource costs as well as a need for health and safety considerations. The team has surveyed potential users and found the concept largely acceptable. All that said, chewing and swallowing a millet knife and fork at the end of one's meal may not be to everyone's taste.

Mitochondrial DNA: Are some mutations more equal than others?

The team studied eight different tissues – ranging from the kidney, to the brain and the heart – in young and old mice which were 4.5 and 26 months old. This resulted in an unprecedently large dataset consisting of around 80,000 somatic mtDNA mutations, showing that the rate of accumulation and the composition of mutations vary between different tissues. The highest accumulation rate was in the kidney, where mutations reached the level of one in five mtDNA molecules.

In agreement with previous studies, Sanchez-Contreras et al. observed a high proportion of transition mutations, in which purine (adenine and guanine) and pyrimidine (thymine and cytosine) nucleotide bases are only exchanged for other purines or pyrimidines, respectively. An unusually high proportion of transversion mutations – where a purine changes to a pyrimidine, or vice versa – were also detected. However, unlike the transition mutations, these transversions did not clonally expand and did not accumulate with age in any of the tissues studied. Because new transversions are constantly being generated (mostly through damage caused by reactive oxygen species), lack of accumulation with age implies that these mutations are excluded from being propogated in somatic cells.

Intriguingly, another study also found a high proportion of transversion mutations in the mtDNA of mouse egg cells , which was surprising given that the proportion of inherited mutations that are transversions is usually very low. This suggests that transversion mutations are excluded from being propagated in germ cells as well.

Part 2

Why do transversions not expand and accumulate with age? And why do transversion and transition mutations behave differently?

Despite using a duplex sequencing approach, it is possible that the transversions they detect might have been potentially generated in vitro from real in vivo DNA damage.

The researchers built a model to understand this: there are two broad classes of mtDNA molecules (Figure 1): a ‘stem subpopulation’ of actively replicating mtDNAs which are responsible for renewing the mtDNA pool, and a ‘worker subpopulation’ which are located in actively respiring mitochondria. ‘Stem’ mtDNAs reside in mitochondria that respire less and are therefore protected from reactive oxygen species. Consequently, transversions primarily occur on ‘worker’ mtDNA molecules which rarely replicate, which prevents these mutations from being able to clonally expand and accumulate with age. 

https://elifesciences.org/articles/87194?utm_source=content_alert&a...

Part 3

HOW Does Carbon Dioxide Trap Heat?

Networks of Silver Nanowires Appear to Learn And Remember Like The Human Brain

New research explores non-biological systems that are more like human brains. In a new study published in Science Advances, researchers found self-organizing networks of tiny silver wires appear to learn and remember in much the same way as the thinking hardware in our heads.

This is a part of a field of research called neuromorphics, which aims to replicate the structure and functionality of biological neurons and synapses in non-biological systems.

The work focuses on a system that uses a network of "nanowires" to mimic the neurons and synapses in the brain.

These nanowires are tiny wires about one thousandth the width of a human hair. They are made of a highly conductive metal, such as silver, typically coated in an insulating material like plastic.

Nanowires self-assemble to form a network structure similar to a biological neural network. Like neurons, which have an insulating membrane, each metal nanowire is coated with a thin insulating layer.

When we stimulate nanowires with electrical signals, ions migrate across the insulating layer and into a neighboring nanowire (much like neurotransmitters across synapses). As a result, we observe synapse-like electrical signaling in nanowire networks.

Part 1

New work uses this nanowire system to explore the question of human-like intelligence. Central to the investigation are two features indicative of high-order cognitive function: learning and memory.

This study demonstrates we can selectively strengthen (and weaken) synaptic pathways in nanowire networks. This is similar to "supervised learning" in the brain.

In this process, the output of synapses is compared to a desired result. Then the synapses are strengthened (if their output is close to the desired result) or pruned (if their output is not close to the desired result).

Researchers expanded on this result by showing they could increase the amount of strengthening by "rewarding" or "punishing" the network. This process is inspired by "reinforcement learning" in the brain.

Part 2

The network "remembered" previous signals for at least seven steps. Curiously, seven is often regarded as the average number of items humans can keep in working memory at one time.

When researchers used reinforcement learning, they saw dramatic improvements in the network's memory performance.

In tehir nanowire networks, they found the formation of synaptic pathways depends on how those synapses have been activated in the past. This is also the case for synapses in the brain, where neuroscientists call it "metaplasticity".

Synthetic intelligence

Human intelligence is still likely a long way from being replicated.

Nonetheless, this research on neuromorphic nanowire networks shows it is possible to implement features essential for intelligence – such as learning and memory – in non-biological, physical hardware.

Nanowire networks are different from the artificial neural networks used in AI. Still, they may lead to so-called "synthetic intelligence".

Perhaps a neuromorphic nanowire network could one day learn to have conversations that are more human-like than ChatGPT, and remember them.

https://www.science.org/doi/10.1126/sciadv.adg3289

https://theconversation.com/networks-of-silver-nanowires-seem-to-le...

Part 3

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Two-component system could offer a new way to halt internal bleeding

Blood loss from traumatic events such as car crashes contributes to more than 2.5 million deaths per year worldwide. This kind of blunt trauma can cause internal bleeding from organs such as the liver, which is difficult to detect and treat. In such cases, it's critical to stop the bleeding as soon as possible, until a patient can be transported to the hospital for further treatment. Finding ways to prevent internal bleeding could have an especially significant impact in the armed services, where delayed treatment for internal hemorrhage is one of the largest causes of preventable death.

Engineers have now designed a two-component system that can be injected into the body and help form blood clots at the sites of internal injury. These materials, which mimic the way that the body naturally forms clots, could offer a way to keep people with severe internal injuries alive until they can reach a hospital.

When internal injuries occur, platelets are attracted to the site and initiate the blood clotting cascade, which eventually forms a sticky plug of platelets and clotting proteins, including fibrinogen. However, if patients are losing a lot of blood, they don't have enough platelets or fibrinogen to form clots. The engineer team wanted to create an artificial system that could help save people's lives by replacing both of those clotting components.

In a mouse model of internal injury, the researchers showed that these components—a nanoparticle and a polymer—performed significantly better than hemostatic nanoparticles that were developed earlier.

What was especially remarkable about these results was the level of recovery from severe injury they saw in the animal studies.

Unlike previously developed hemostatic systems, the new technology mimics the actions of both platelets—the cells that initiate blood clotting—and fibrinogen, a protein that helps forms clots. The idea of using two components allows selective gelation of the hemostatic system as the concentration is enhanced in the wound, mimicking the end effect of the natural clotting cascade.

What researchers in this area have been doing in the past is trying to either recapture the therapeutic effects of platelets or recapture the function of fibrinogen. This new one tried to capture the way they interact with each other.

To achieve that, the researchers created a system with two types of materials: a nanoparticle that recruits platelets and a polymer that mimics fibrinogen.

Part 1

For this paper, the researchers modified those particles by adding a chemical group that would react with a tag placed on the second component in the system, which they call the crosslinker. Those crosslinkers, made of either PEG or PEG-PLGA, bind to the targeting particles that have accumulated at a wound site and form clumps that mimic blood clots. 

The idea is that with both of these components circulating inside the bloodstream, if there is a wound site, the targeting component will start accumulating at the wound site and also bind the crosslinker. When both components are at high concentration, you get more cross-linking, and they begin forming that glue and helping the clotting process.

To test the system, the researchers used a mouse model of internal injury. They found that after being injected into the body, the two-component system was highly effective at stopping bleeding, and it worked about twice as well as the targeting particle on its own.

Another important advantage of the clots is that they don't degrade as fast as naturally occurring clots do. When patients lose a lot of blood, they are usually given saline intravenously to keep up their blood pressure, but this saline also dilutes the existing platelets and fibrinogen, leading to weaker clots and faster degradation. However, the artificial clots are not as susceptible to this kind of degradation, the researchers found.

The researchers also found that their nanoparticles did not induce any significant immune reaction in the mice compared to a glucose control. They now plan to test the system in a larger animal model.

Celestine Hong et al, Engineering a Two‐Component Hemostat for the Treatment of Internal Bleeding through Wound‐Targeted Crosslinking, Advanced Healthcare Materials (2023). DOI: 10.1002/adhm.202202756

Part 2

Earliest animal likely used chemical signaling to evolve into multicellular organism

The earliest animal likely used chemical signaling to evolve from a single cell to a multicellular organism, according to a study by scientists. The findings provide new information about how one of the biggest transitions in the history of life on Earth likely occurred.

The general view is that animals evolved from a unicellular organism, and this research helps explain how that may have happened and how those cells chose whether to be together or on their own.

The study focused on one of the closest living relatives of animals, Capsaspora owczarzaki, which lives in snails. Capsaspora can form multicellular aggregates—cells that cluster together and adhere to each other—in a way that is similar to sponges or hydra.

To conduct their study, researchers systematically added and removed components of a liquid growth media to Capsaspora to determine which components regulated the cells adhering together. They discovered that calcium ions and lipids spurred multicellular aggregation. They also found that the process was reversible, and that when lipoproteins decreased, the cells separated.

The transition from being a single cell to a multicellular organism is a really big step. We now have a better understanding of how the ancestors of animals could have made that change using chemical cues.

Researchers are working on additional studies involving Capsaspora. The snail that Capsaspora resides in transmits a parasitic disease, and Capsaspora can kill the worm that causes the disease. If researchers can determine how the organism does that, there could be future medical applications.

Part 1

The ongoing research aligns with the mission  where chemists are trying to discover the chemical "languages" of micro-organisms. Microbes use chemicals to communicate with each other, and then they use other chemicals to cooperate with or compete with each other. The researchers are applying chemical tools like

mass spectrometry and nuclear magnetic resonance spectroscopy  to decipher which molecules trigger cooperative and competitive responses in microbes.

Ultimately, they hope to use this knowledge to devise new approaches to defeat pathogens and promote the microbiomes that help humans.

 Núria Ros-Rocher et al, Chemical factors induce aggregative multicellularity in a close unicellular relative of animals, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2216668120

Part 2

How to land on a planet safely using a computational model

Understanding the interaction between the rocket plume and the surface is important for the safety and success of space missions in terms of contamination and erosion, landing accuracy, planetary protection, and engineering design, as well as for scientific understanding and future exploration.

When a lander descends toward the moon—or a rocky planet, asteroid, or comet—the exhaust plume of the rocket interacts with the surface, causing erosion and kicking up regolith particles. The resulting blanket of dusty debris can create a dangerous brownout effect, limiting visibility and potentially damaging the spacecraft or nearby equipment.

Researchers developed a model to describe the interaction between a rocket plume and the surface of a planetary body in near-vacuum conditions. The results can be used to evaluate the safety and feasibility of a proposed landing site and to optimize the design of spacecraft and rocket engines for planetary landings.

The computational framework takes in information about the rocket, its engines, and the surface composition and topography, as well as the atmospheric conditions and gravitational forces at the landing site.

By considering the interaction of the gas with solid particles as a system of equations, the simulation estimates the shape and size of the plume, the temperature and pressure of the plume and surface, and the amount of material eroded or displaced. It does so in a way that is more computationally efficient than previous methods.

In the model, small regolith particles reached high altitudes and caused severe brownout effects during ascent and descent. In contrast, larger particles with increased bed height led to a more favorable brownout status.

The insights gained from this study of the effects of different parameters on plume-surface interaction can inform the development of more effective and efficient landing technologies.

The researchers plan to improve the capabilities of the framework to include more complex physics, such as chemical reactions and solid particle collisions. They think the model can be applied to other physics scenarios including needle-free drug delivery systems.

Omid Ejtehadi et al, Full continuum approach for simulating plume-surface interaction in planetary landings, Physics of Fluids (2023). DOI: 10.1063/5.0143398

 How NASA is planning to protect Earth from asteroids and comets

NASA just released a new planetary defense strategy and action plan, describing its efforts to find and identify potentially hazardous objects to provide an advanced warning, and then even push them off an impact trajectory.

This 10-year strategy looks to advance efforts to protect the Earth from a devastating encounter with a Near Earth asteroid or comet.

The 46-page "NASA Planetary Defense Strategy and Action Plan" (pdf document) was released on April 18, 2023 and follows another document that was put out on April 3 by the White House Office of Science and Technology Policy, "National Preparedness Strategy and Action Plan for Near-Earth Object Hazards and Planetary Defense" (pdf document).

Each of the reports focuses on enhancing the detection, characterization and responses to impact threats as well as improving international cooperation for coordinating strategies among government agencies.

NASA wants to focus on six key areas for planetary defense over the next decade:

• Improving NEO survey, detection, and characterization efforts to work toward a completed catalog of all NEOs that might pose an impact hazard to Earth
• Developing and demonstrating NEO mitigation technologies similar to the agency's Double Asteroid Redirection Test (DART) mission, the world's first planetary defense test mission, which successfully demonstrated one method of asteroid deflection using a kinetic impactor spacecraft
• Fostering international collaboration related to NEO surveying and mitigation to leverage international capabilities
• Strengthening interagency coordination between NASA and other U.S. government agencies to enhance and streamline U.S. government NEO preparedness and response planning
• Review the agency's internal planning to maximize the benefits obtained from limited resources
• Better integrate messaging regarding planetary defense work with the agency's strategic communications

Each of the strategy objectives are defined into short-term, medium-term, long-term, and ongoing timelines with the goal of meeting all objectives within the next 10 years.

https://www.nasa.gov/feature/nasa-releases-agency-strategy-for-plan...

https://www.universetoday.com/161058/heres-how-nasa-is-planning-to-...

Earpiece that speeds up recovery after a stroke

Astronomers solve the 60-year mystery of quasars, the most powerful objects in the universe

Scientists have unlocked one of the biggest mysteries of quasars—the brightest, most powerful objects in the universe—by discovering that they are ignited by galaxies colliding.

First discovered 60 years ago, quasars can shine as brightly as a trillion stars packed into a volume the size of our solar system. In the decades since they were first observed, what could trigger such powerful activity has remained a mystery. New work by scientists has now revealed that it is a consequence of galaxies crashing together.

The collisions were discovered when researchers, using deep imaging observations from the Isaac Newton Telescope in La Palma, observed the presence of distorted structures in the outer regions of the galaxies that are home to quasars.

Most galaxies have supermassive black holes at their centers. They also contain substantial amounts of gas—but most of the time this gas is orbiting at large distances from the galaxy centers, out of reach of the black holes. Collisions between galaxies drive the gas towards the black hole at the galaxy center; just before the gas is consumed by the black hole, it releases extraordinary amounts of energy in the form of radiation, resulting in the characteristic quasar brilliance.

The ignition of a quasar can have dramatic consequences for entire galaxies—it can drive the rest of the gas out of the galaxy, which prevents it from forming new stars for billions of years into the future.

This is the first time that a sample of quasars of this size has been imaged with this level of sensitivity. By comparing observations of 48 quasars and their host galaxies with images of over 100 non-quasar galaxies, researchers concluded that galaxies hosting quasars are approximately three times as likely to be interacting or colliding with other galaxies.

J C S Pierce et al, Galaxy interactions are the dominant trigger for local type 2 quasars, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad455

Do volcanoes add more carbon than they take away?

In a new study published in the Journal of Geophysical Research: Biogeosciences, researchers discovered that a volcano in northeast China emits a small net amount of carbon each year. Over geological timescales, that could have a significant impact on our planet's carbon cycle.

Volcanic areas continue to emit carbon dioxide long after eruptions are over. Conversely, atmospheric carbon dioxide (CO₂) is constantly locked away into minerals on Earth's surface through a process called silicate weathering. Whether volcanoes release more CO₂ through degassing or capture more CO₂ through silicate weathering is an open question.

The authors of the new study investigated whether the Changbaishan volcanic area in northeast China is a net source or sink of atmospheric carbon. The region has been active for at least 2.7 million years, but it has not erupted since 1903, making the area a prime spot for analyzing long-term carbon leakage.

Part 1

Over the course of two field seasons, in 2019 and 2020, the study authors scoured the Changbaishan region for rivers and streams. They collected water samples from around two dozen sites and used radiocarbon dating to estimate the amount of "deep carbon," meaning carbon from the depths of Earth, that had seeped into the water. They compared deep carbon estimates to estimates of carbon incorporated into minerals through silicate weathering.

The researchers found that the Changbaishan region is a small net carbon source. Every year, the region releases at least 600 more tons of carbon than it incorporates—about the amount that 41 average Americans put into the atmosphere on an annual basis. That seems small, but over geological timescales, the impact could be significant.

The Changbaishan volcanic region is just one of many around the world, the researchers point out. Future work should examine wider areas to gain a full understanding of how volcanoes contribute to Earth's carbon cycle.

Newly observed effect makes atoms transparent to certain frequencies of light

A newly discovered phenomenon dubbed "collectively induced transparency" (CIT) causes groups of atoms to abruptly stop reflecting light at specific frequencies.

CIT was discovered by confining ytterbium atoms inside an optical cavity —essentially, a tiny box for light—and blasting them with a laser. Although the laser's light will bounce off the atoms up to a point, as the frequency of the light is adjusted, a transparency window appears in which the light simply passes through the cavity unimpeded.

An analysis of the transparency window points to it being the result of interactions in the cavity between groups of atoms and light. This phenomenon is akin to destructive interference, in which waves from two or more sources can cancel one another out. The groups of atoms continually absorb and re-emit light, which generally results in the reflection of the laser's light. However, at the CIT frequency, there is a balance created by the re-emitted light from each of the atoms in a group, resulting in a drop in reflection.

An ensemble of atoms strongly coupled to the same optical field can lead to unexpected results.

Through conventional quantum optics measurement techniques, researchers found that their system had reached an unexplored regime, revealing new physics.

Besides the transparency phenomenon, the researchers also observed that the collection of atoms can absorb and emit light from the laser either much faster or much slower compared to a single atom depending on the intensity of the laser. These processes, called superradiance and subradiance, and their underlying physics are still not understood properly because of the large number of interacting quantum particles.

 Mi Lei et al, Many-body cavity quantum electrodynamics with driven inhomogeneous emitters, Nature (2023). DOI: 10.1038/s41586-023-05884-1

Scientists slow aging by engineering longevity in cells

Human lifespan is related to the aging of our individual cells. Three years ago a group of  researchers deciphered essential mechanisms behind the aging process. After identifying two distinct directions that cells follow during aging, the researchers genetically manipulated these processes to extend the lifespan of cells.

As described in a new article published April 27, 2023, in Science, the team has now extended this research using synthetic biology to engineer a solution that keeps cells from reaching their normal levels of deterioration associated with aging.

Cells, including those of yeast, plants, animals and humans, all contain gene regulatory circuits that are responsible for many physiological functions, including aging. These gene circuits can operate like our home electric circuits that control devices like appliances and automobiles.

However, the researchers  uncovered that, under the control of a central gene regulatory circuit, cells don't necessarily age the same way. Imagine a car that ages either as the engine deteriorates or as the transmission wears out, but not both at the same time. They envisioned a "smart aging process" that extends cellular longevity by cycling deterioration from one aging mechanism to another.

In the new study, the researchers genetically rewired the circuit that controls cell aging. From its normal role functioning like a toggle switch, they engineered a negative feedback loop to stall the aging process. The rewired circuit operates as a clock-like device, called a gene oscillator, that drives the cell to periodically switch between two detrimental "aged" states, avoiding prolonged commitment to either, and thereby slowing the cell's degeneration.

These advances resulted in a dramatically extended cellular lifespan, setting a new record for life extension through genetic and chemical interventions.

The researchers in this study first used computer simulations of how the core aging circuit operates. This helped them design and test ideas before building or modifying the circuit in the cell. This approach has advantages in saving time and resources to identify effective pro-longevity strategies, compared to more traditional genetic strategies.

This is the first time computationally guided synthetic biology and engineering principles were used to rationally redesign gene circuits and reprogram the aging process to effectively promote longevity.

Zhen Zhou et al, Engineering longevity—Design of a synthetic gene oscillator to slow cellular aging, Science (2023). DOI: 10.1126/science.add7631. www.science.org/doi/10.1126/science.add7631

What makes the human genome unique?

Over the past 100 million years, mammals have adapted to nearly every environment on Earth.

Scientists with the Zoonomia Project have been cataloging the diversity in mammalian genomes by comparing DNA sequences from 240 species that exist today, from the aardvark and the African savanna elephant to the yellow-spotted rock hyrax and the zebu.

This week, in several papers in a special issue of Science, the Zoonomia team has demonstrated how comparative genomics can not only shed light on how certain species achieve extraordinary feats, but also help scientists better understand the parts of our genome that are functional and how they might influence health and disease.

In the new studies, the researchers identified regions of the genomes, sometimes just single letters of DNA, that are most conserved, or unchanged, across mammalian species and millions of years of evolution—regions that are likely biologically important. They also found part of the genetic basis for uncommon mammalian traits such as the ability to hibernate or sniff out faint scents from miles away. And they pinpointed species that may be particularly susceptible to extinction, as well as genetic variants that are more likely to play causal roles in rare and common human diseases.

The findings come from analyses of DNA samples collected by more than 50 different institutions worldwide which provided many genomes from species that are threatened or endangered.

Part 1

The researchers found that at least 10% of the human genome is highly conserved across species, with many of these regions occurring outside of protein-coding genes. More than 4,500 elements are almost perfectly conserved across more than 98% of the species studied

Most of the conserved regions—which have changed more slowly than random fluctuations in the genome—are involved in embryonic development and regulation of RNA expression. Regions that changed more frequently shaped an animal's interaction with its environment, such as through immune responses or the development of its skin.

The researchers also pinpointed parts of the genome linked to a few exceptional traits in the mammalian world, such as extraordinary brain size, superior sense of smell, and the ability to hibernate during the winter.

With an eye toward preserving biodiversity, the researchers found that mammals with fewer genetic changes at conserved sites in the genome were at greater risk for extinction.

They used the mammalian genomes to study human traits and diseases. They focused on some of the most conserved single-letter genomic regions uncovered in the first paper and compared them to genetic variants that scientists have previously linked to diseases such as cancer using other methods.

The team found that their annotations of the genome based on evolutionary conservation revealed more connections between genetic variants and their function than the other methods. They also identified mutations that are likely causal in both rare and common diseases including cancer, and showed that using conservation in disease studies could make it easier to find genetic changes that increase risk of disease.

Part 2

Researchers also examined more than 10,000 genetic deletions specific to humans using both Zoonomia data and experimental analysis, and linked some of them to the function of neurons.

Other Zoonomia papers published recently revealed that mammals diversified before the mass dinosaur extinction; uncovered a genetic explanation for why a famous sled dog from the 1920s named Balto was able to survive the harsh landscape of Alaska; discovered human-specific changes to genome organization; used machine learning to identify regions of the genome associated with brain size; described the evolution of regulatory sequences in the human genome; focused on sequences of DNA that move around the genome; discovered that species with smaller populations historically are at higher risk of extinction today; and compared genes between nearly 500 species of mammals.

 Sacha Vignieri, Zoonomia, Science (2023). DOI: 10.1126/science.adi1599. www.science.org/doi/10.1126/science.adi1599

Aryn P. Wilder et al, The contribution of historical processes to contemporary extinction risk in placental mammals, Science (2023). DOI: 10.1126/science.abn5856. www.science.org/doi/10.1126/science.abn5856

 Katherine L. Moon et al, Comparative genomics of Balto, a famous historic dog, captures lost diversity of 1920s sled dogs, Science (2023). DOI: 10.1126/science.abn5887. www.science.org/doi/10.1126/science.abn5887

Part 3

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Using microbes to get more out of mining waste

Researchers have developed a new mining technique which uses microbes to recover metals and store carbon in the waste produced by mining. Adopting this technique of reusing mining waste, called tailings, could transform the mining industry and create a greener and more sustainable future.

Tailings are a by-product of mining. They are the fine-grained waste materials left after extracting the target ore mineral, which are then stacked and stored. This method is called dry-stack tailing.

Over time, mining practices have evolved and become more efficient. But the climate crisis and rising demand for critical minerals require the development of new ore removal and processing technologies.

Old tailings contain higher amounts of critical minerals that can be extracted with the help of microbes through a process called bioleaching. The microbes help break down the ore, releasing any valuable metals that weren't fully recovered in an eco-friendly way that is much faster than natural biogeochemical weathering processes.

We can now take tailings that were produced in the past and recover more resources from those waste materials and, in doing so, also reduce the risk of residual metals entering into local waterways or groundwater.

In addition to improving resource recovery, the microbes capture carbon dioxide from the air and store it within the mine tailings as new minerals. This process aids in offsetting some of the emissions released while the mine was active and helps stabilize the tailings.

Microbial mineral carbonation could offset more than 30 per cent of a mine sites annual greenhouse gas emissions if applied to an entire mine. In addition, this microbial-driven technique gives value to historical mine tailings that are otherwise considered industrial waste.

Jenine McCutcheon et al, Microbially mediated carbon dioxide removal for sustainable mining, PLOS Biology (2023). DOI: 10.1371/journal.pbio.3002026

How shading crops with solar panels can improve farming, lower food...

If you have lived in a home with a trampoline in the backyard, you may have observed the unreasonably tall grass growing under it. This is because many crops, including these grasses, actually grow better when protected from the sun, to an extent.

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We need to talk about gene-therapy prices

At US$3.5 million per treatment, the haemophilia gene therapy Hemgenix is the most expensive drug in the world. Other gene therapies are expected to carry similarly eye-watering p.... This puts them out of the reach of many who need them and diminishes government funders’ willingness to pay for related research. “Researchers, especially health economists, must work urgently with industry and governments to find a more affordable funding model,” argues a Nature editorial.

Plastic Particles Found in The Brains of Mice Just Two Hours After They Ate

Thanks to their flexibility, durability, and affordability, plastics have oozed their way into just about every aspect of our lives. When these items do eventually break down, the resulting micro- and nanoplastics (MNPs) can harm wildlife, the environment, and ourselves. MNPs have been found in blood, lungs, and placenta, and we know that they can get into our bodies through the food and liquids we consume.

A new study by a team of researchers from Austria, the US, Hungary, and the Netherlands has found MNPs can reach the brain a few hours after being eaten, possibly thanks to the way other chemicals stick to their surface.

Not only is the speed alarming, the very possibility of tiny polymers sliding into our nervous system raises some serious alarm bells.

In the brain, plastic particles could increase the risk of inflammation, neurological disorders or even neurodegenerative diseases such as Alzheimer's or Parkinson's.

In the study, tiny fragments of MNPs orally administered to mice were detectable in their brains in as little as two hours. But how do MNPs get through the blood-brain barrier, which is supposed to keep the brain safe?

As a system of blood vessels and tightly packed surface tissue, the blood-brain barrier helps shield our brains from potential threats by blocking the passage of toxins and other undesirables, while permitting more useful substances across. It stands to reason that plastic particles would count as a material to keep well and truly out of the brain's sensitive tissues.

With the help of computer models, scientists discovered that a certain surface structure (biomolecular corona) was crucial in enabling plastic particles to pass into the brain.

To verify that the particles truly can enter the brain, polystyrene (a common plastic used in food packaging) MNPs in three sizes (9.5, 1.14, and 0.293 micrometers) were labeled with fluorescent markers and pretreated in a mixture similar to digestive fluid before being fed to mice.

The researchers  found specific nanometer-sized green fluorescent signals in the brain tissue of MNP-exposed mice after only two hours!

Only 0.293 micrometer sized particles were able to be taken up from the gastrointestinal tract and to penetrate the blood brain barrier.

How these tiny, blanketed plastics cross cell barriers in the body is complicated and depends on factors like particle size, charge, and cell type.

Tinier plastic particles have a higher surface area-to-volume ratio, making them more reactive and potentially more hazardous than larger microplastics. This reactivity is thought to allow the small bits of plastic to gather other molecules around them, hugging them tight with molecular forces to form a durable cloak called a corona.

Part 1

Four different plastic models were used to study the role of the plastic particle' corona. The simulations showed that particles with a protein corona couldn't enter the barrier. However, those with a cholesterol corona could cross, even if they couldn't progress deeper into brain tissue.

The results raise the possibility that plastic can be transported across the membrane and into the brain tissue with the help of the right molecular cocktail. Knowing the fundamental mechanisms is an important first step in managing their harmful effects.

https://www.mdpi.com/2079-4991/13/8/1404

A neural circuit that suppresses male aggression when an opponent is physically advantaged

For decades, neuroscientists have been trying to understand the neural mechanisms underpinning different social behaviors, including aggression. Aggressive, violent, or confrontational behaviors are common among humans and many animal species, yet the neural processes supporting or suppressing these behaviors have not been fully unveiled yet.

Researchers recently unveiled an area in the hypothalamus, brain region influencing the nervous system and the release of hormones, that suppresses aggression in male mice when they are confronting a stronger or physically "superior" opponent. Their findings, published in Nature Neuroscience, shed some new light on the neural pathways modulating aggression in animals and potentially also humans.

Previously, scientists found that VMHvl is an essential region for generating aggression.

While conducting their studies, researchers realized that rostral (i.e., frontal) and caudal (i.e., posterior) parts of the MPOA, an area of the hypothalamus, responded differently while mice were socially interacting with each other. They found that the caudal MPOA tended to be more active during interactions between two males than during interactions between male and female mice.

When they manipulated the caudal MPOA, they found that aggression is strongly suppressed. They then considered the potential situation under which male aggression towards another male could be suppressed. This led them to discover that cMPOA cell activity increases when a male encounters a stronger opponent.

To conduct their recent experiments, the researchers used a combination of optogenetic and chemogenetic techniques. They recorded calcium activity in the mice's brain using fiber photometry, an optogenetic technique, and also collected patch clamp recordings in slices of the mouse brain.

Using optogenetic techniques, they also inhibited or activated cells in the cMPOA of living male mice and observed their resulting behaviour during social interactions. Interestingly, the inhibition of these cells appeared to increase the male mice's aggression towards other males, while activating them decreased the mice's aggressive behaviours.

These findings suggest that cMPOA cells naturally suppress aggression.

Overall, the findings gathered in this study suggest that the posterior part of the MPOA can significantly influence aggressive behaviour between male mice. Specifically, this area of the hypothalamus appears to reduce aggression towards a stronger male opponent, by suppressing activity in the VMHvl.

Dongyu Wei et al, A hypothalamic pathway that suppresses aggression toward superior opponents, Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01297-5

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MRI imaging method captures brain glucose metabolism without administering radioactive substances

Metabolic disorders play a central role in many common conditions, including Alzheimer's, depression, diabetes and cancer, which call for reliable as well as non-invasive diagnostic procedures. Until now, radioactive substances have been administered as part of the process of mapping glucose metabolism in the brain.

Now, a research team has developed a completely new magnetic resonance imaging (MRI) approach. Using a harmless glucose solution, the procedure generates reliable results and—in principle—can be used with all common MRI scanners. The findings from the study have just been published in the journal Nature Biomedical Engineering.

The study looked at—and has significantly enhanced—current diagnostic procedures for mapping brain glucose metabolism. The results were generated by measuring blood glucose levels and metabolic products in healthy subjects several times during a period of around 90 minutes. In contrast to existing procedures, the subjects did not receive radio-labeled glucose but a quantity of a harmless glucose solution equivalent to a can of a fizzy drink. As this substance does not produce a direct signal for the MR imaging method used, concentrations and metabolism of glucose were measured indirectly based on the drop in signal intensity for the product concerned.

The main advantage of this indirect method is that it can be used on other MR devices without any difficulties, because no additional hardware components are required, as is the case with other, comparable approaches.

 Petr Bednarik et al, 1H magnetic resonance spectroscopic imaging of deuterated glucose and of neurotransmitter metabolism at 7 T in the human brain, Nature Biomedical Engineering (2023). DOI: 10.1038/s41551-023-01035-z

Fabian Niess et al, Noninvasive 3-Dimensional 1H-Magnetic Resonance Spectroscopic Imaging of Human Brain Glucose and Neurotransmitter Metabolism Using Deuterium Labeling at 3T, Investigative Radiology (2023). DOI: 10.1097/RLI.0000000000000953

Study finds only 6% of nations provide for citizens in a just, sustainable manner

Researchers  have developed a framework for quantifying how well countries around the world are doing at providing adequate food, energy and water to their citizens without exceeding nature's capacity to meet those needs.

They found that only 6% of 178 countries provide for all their citizens in an ecologically sustainable way in both carbon sequestration and water consumption.

The study found that while 67% of nations operate safely and sustainably in regard to water use, only 9% do so in regard to carbon sequestration, or reducing their greenhouse gas emissions.

For a country to be self-sufficient, its population needs access to food, water and energy, resources that can often only be provided by the surrounding ecosystem. Yet because human activities tend to cause unintended side effects like global warming or ozone depletion, it's imperative that experts look for ways to develop society in an ecologically sustainable manner. At the same time, in order to be socially just, countries need to secure resources to meet the basic needs of all of its citizens.

Ideally, human activities should exist between the limits of a society's ecological ceiling and its social foundation, a boundary that describes the resources necessary to avoid critical human deprivation of food, water or energy.

Part 1

If you are exceeding the ecological ceiling, then you're not sustainable from an environmental perspective. If you're below the social foundation, then you're not meeting basic human needs, and that can be frustrating from an equity point of view.

The team found that the majority of countries emit far more than their national ecosystem can handle in terms of carbon, but tend to operate close to their water supply limits.

Sometimes countries do not have much of a choice. Findings showed that 37% of countries do not have the ability to provide for their citizens in a safe and just way in terms of carbon sequestration, and 10% lack the ability to do that with regard to water.

While the socioeconomic status of countries is often related to how well they can provide for their citizens in a sustainable manner, it doesn't always work that way, the researchers said.

Despite the study's potentially bleak outlook, the researchers think their work offers a glimmer of hope in combating the environmental risks of human development. The team's results imply that many nations could secure the necessary resources they need to thrive at a much lower demand than current levels suggest.

One way to do this would be to adopt more renewable energy resources, introduce more plant-based diets into our food cycles, and change the way we produce certain goods and services to develop a sustainable circular economy instead of a linear one.

 Yazeed M. Aleissa et al, Possible but rare: Safe and just satisfaction of national human needs in terms of ecosystem services, One Earth (2023). DOI: 10.1016/j.oneear.2023.03.008

Part 2

Scientists design new bio-inspired molecules to promote bone regeneration

People's ability to regenerate bones declines with age and is further decreased by diseases such as osteoporosis. To help the aging population, researchers are looking for new therapies that improve bone regeneration.

Now, an interdisciplinary team of researchers  developed novel bio-inspired molecules that enhance bone regeneration in mice. The results were published in the journal Biomaterials.

As people age, their ability to regenerate bones decreases. Fractures take longer to heal and diseases like osteoporosis only add to it. This represents a serious health challenge to the aging population and an increasing socioeconomic burden for the society. To help combat this issue, researchers are looking for new therapeutic approaches that can improve bone regeneration.

A team of scientists  used computer modeling and simulations to design novel bio-inspired molecules to enhance bone regeneration in mice. The new molecules can be incorporated into biomaterials and applied locally to bone defects. These new molecules are based on glycosaminoglycans, which are long-chained sugars such as hyaluronic acid or heparin.

 Gloria Ruiz-Gómez et al, Rational engineering of glycosaminoglycan-based Dickkopf-1 scavengers to improve bone regeneration, Biomaterials (2023). DOI: 10.1016/j.biomaterials.2023.122105

Newly discovered electrical activity within cells could change the way researchers think about biological chemistry

The human body relies heavily on electrical charges. Lightning-like pulses of energy fly through the brain and nerves and most biological processes depend on electrical ions traveling across the membranes of each cell in our body.

These electrical signals are possible, in part, because of an imbalance in electrical charges that exists on either side of a cellular membrane. Until recently, researchers thought the membrane was an essential component to creating this imbalance. But that thought was turned on its head when researchers discovered that similar imbalanced electrical charges can exist between microdroplets of water and air.

Now, researchers have discovered that these types of electric fields also exist within and around another type of cellular structure called biological condensates. Like oil droplets floating in water, these structures exist because of differences in density. They form compartments inside the cell without needing the physical boundary of a membrane.

Inspired by previous research demonstrating that microdroplets of water interacting with air or solid surfaces create tiny electrical imbalances, the researchers decided to see if the same was true for small biological condensates. They also wanted to see if these imbalances sparked reactive oxygen, "redox," reactions like these other systems.

Appearing on April 28 in the journal Chem, their foundational discovery could change the way researchers think about biological chemistry. It could also provide a clue as to how the first life on Earth harnessed the energy needed to arise.

Yifan Dai et al, Interface of biomolecular condensates modulates redox reactions, Chem (2023). DOI: 10.1016/j.chempr.2023.04.001

Near-universal T cell immunity towards a broad range of bacteria discovered

 Typically T cells of the immune system respond to a specific feature (antigen) of a microbe, thereby generating protective immunity. As reported in the journal Immunity, an international team of scientists have discovered an exception to this rule. Namely, a group of divergent bacterial pathogens, including pneumococci, all share a small highly conserved protein sequence, which is both presented and recognized by human T cells in a conserved population-wide manner.

The study set out to understand immune mechanisms that protect against pneumococcus, a bacterial pathobiont that can reside harmlessly in the upper respiratory mucosae but can also cause infectious disease, especially in infants and older adults, which can range from middle ear and sinus infections to pneumococcal pneumonia and invasive bloodstream infections.

The researchers identified a crucial fragment of the pneumococcal toxin pneumolysin that was commonly presented by a particular class of human antigen presenting molecules and recognized by T cells from most people who naturally develop specific immunity to pneumococcal proteins.

The study further found that the uniformly presented and broadly recognized bacterial protein fragment was not unique for the pneumococcal pneumolysin but was shared by a large family of bacterial so-called cholesterol dependent cytolysins (CDCs). These are produced by divergent bacterial pathogens mostly affecting humans and cause a range of respiratory, gastro-intestinal, or vaginal infectious diseases.

Jamie Rossjohn, CD4+ T cell-mediated recognition of a conserved cholesterol-dependent cytolysin epitope generates broad antibacterial immunity, Immunity (2023). DOI: 10.1016/j.immuni.2023.03.020. www.cell.comimmunity/fulltext/ … 1074-7613(23)00140-1

A new treatment for multidrug-resistant bacteria

What makes landing on the Moon very difficult ?

Compared with Earth,  the Moon has reduced gravity, very little atmosphere and lots of dust.

To pull off a successful landing, engineers need to anticipate how a spacecraft will interact with this environment — and spend money testing how things might go wrong. Tests, tests and more tests are needed to prove out the landing system in as many scenarios as possible.And even then, nothing is guaranteed.

 In the 1960s, when the United States and the Soviet Union were racing to land there, they crashed spacecraft after spacecraft before each finally succeeded in 1966.

The government space agencies were able to learn from each landing attempt. Today, by contrast, private companies are expected to repeat these successes, without government resources and without lessons gleaned from many failed and successful missions. That’s a lot to ask of a private enterprise to get it right on the first attempt.

In 2013, China landed successfully on the Moon on its first try with its Chang’e 3 mission. China also accomplished the first-ever landing on the far side of the Moon, and brought back samples of Moon rocks. But India, for its part, crashed during its attempt to land on the Moon in 2019; it will try again later this year.

Getting a mission to the Moon, around 384,000 kilometres from Earth, is much more challenging than lofting a satellite into low-Earth orbit — and failures can occur early on, even for missions that don't plan to land. This happened with NASA’s Lunar Flashlight mission, a small spacecraft that launched in December and was supposed to map the Moon’s ice. Its propulsion system malfunctioned soon after launch and may keep it from reaching an orbit from which it can do the intended science.

Even if a lander makes it to the vicinity of the Moon, it still has to navigate its way down to the surface with no global-positioning satellites for guidance and virtually no atmosphere to help to slow it down. Once it gets within the crucial last few kilometres, its software has to deal quickly and autonomously with any last-minute challenges, such as its sensors potentially becoming confused by large amounts of dust kicked up from the surface by exhaust plumes.

Both of the 2019 landing failures probably stemmed from software and sensor issues during these final moments. And early indications suggest that this week’s ispace failure could have been caused by the lander running out of propellant just before it touched down.