Study directly links high insulin levels to pancreatic cancer

A new study from researchers reveals a direct link between high insulin levels, common among patients with obesity and type 2 diabetes, and pancreatic cancer.

The study, published in Cell Metabolism, provides the first detailed explanation of why people with obesity and type 2 diabetes are at an increased risk of pancreatic cancer. The research demonstrates that excessive insulin levels overstimulate pancreatic acinar cells, which produce digestive juices. This overstimulation leads to inflammation that converts these cells into precancerous cells.

While obesity and type 2 diabetes had previously been established as risk factors for pancreatic cancer, the exact mechanisms by which this occurred remained unclear. This new study sheds light on the role of insulin and its receptors in this process.

Hyperinsulinemia acts via acinar insulin receptors to initiate pancreatic cancer by increasing digestive enzyme production and inflammation, Cell Metabolism (2023). DOI: 10.1016/j.cmet.2023.10.003. www.cell.com/cell-metabolism/f … 1550-4131(23)00372-8

Star fishes are just heads!

For centuries, naturalists have puzzled over what might constitute the head of a sea star, commonly called a "starfish." When looking at a worm, or a fish, it's clear which end is the head and which is the tail. But with their five identical arms—any of which can take the lead in propelling sea stars across the seabed—it's been anybody's guess how to determine the front end of the organism from the back. This unusual body plan has led many to conclude that sea stars perhaps don't have a head at all.

Researchers now have published a study finding that the truth is closer to the absolute reverse. In short, while the team detected gene signatures associated with head development just about everywhere in juvenile sea stars, expression of genes that code for an animal's torso and tail sections were largely missing.

Researchers used a variety of high-tech molecular and genomic techniques to understand where different genes were expressed during the development and growth of sea stars. A team  used micro-CT scanning to understand the shape and structure of the animal in unprecedented detail.

In another surprising finding, molecular signatures typically associated with the front-most portion of the head were localized to the middle of each of the sea star's arms, with these signatures becoming progressively more posterior moving out towards the arms' edges.

The research, published Nov. 1 in Nature, suggests that, far from being headless, over evolutionary time sea stars lost their bodies to become only heads.

It's as if the sea star is completely missing a trunk, and is best described as just a head crawling along the seafloor.

Almost all animals, including humans, are bilaterally symmetrical, meaning they can be split into two mirrored halves along a single axis extending from their head to their tail.

But the body plan of sea stars has long confounded scientists' understanding of animal evolution. Instead of displaying bilateral symmetry, adult sea stars—and related echinoderms, such as sea urchins and sea cucumbers—have a five-fold axis of symmetry without a clear head or tail.

 Laurent Formery, Molecular evidence of anteroposterior patterning in adult echinoderms, Nature (2023). DOI: 10.1038/s41586-023-06669-2. www.nature.com/articles/s41586-023-06669-2

New insights into the India–Asia collision in the Western Himalayas dating back to circa 55 million years

New Sangdanlin Section Data Suggests a Large Greater India

Human emissions have increased mercury in the atmosphere sevenfold: Study

Humans have increased the concentration of potentially toxic mercury in the atmosphere sevenfold since the beginning of the modern era around 1500 C.E., according to new research .

Researchers developed a new method to accurately estimate how much mercury is emitted annually from volcanos, the largest single natural emitter of mercury. The team used that estimate—along with a computer model—to reconstruct pre-anthropogenic atmospheric mercury levels. The researchers estimated that before humans started pumping mercury into the atmosphere, it contained on average about 580 megagrams of mercury. However, in 2015, independent research that looked at all available atmospheric measurements estimated the atmospheric mercury reservoir was about 4,000 Mg—nearly 7 times larger than the natural condition estimated in this study. Human emissions of mercury from coal-fired power plants, waste-incineration, industry and mining make up the difference. 

Methylmercury is a potent neurotoxicant that bioaccumulates in fish and other organisms—including us.

 Benjamin M. Geyman et al, Impacts of Volcanic Emissions on the Global Biogeochemical Mercury Cycle: Insights From Satellite Observations and Chemical Transport Modeling, Geophysical Research Letters (2023). DOI: 10.1029/2023GL104667

Double gravitational lenses?!

How cool is it that the very universe we are trying to explore is actually providing us with telescopes to probe the darkest corners of space and time?

The alignment of large clusters of galaxies is the usual culprit whose gravity bends distant light to give us nature's own telescopes, but now our own Quora  physicist Viktor T Toth poses the question, "Can there be multiple gravitational lenses lined up and can they provide a 'communication bridge' to allow civilizations to communicate?"

 Albert Einstein in his general theory of relativity,  describes how the presence of matter can distort space around them. The famous analogy of placing a bowling ball at the center of a large rubber sheet causes a dip centered around the mass of the bowling ball. Any object rolling past the ball would find itself traveling through "curved space" and, therefore, find its path to be altered. This very concept is used successfully by space mission planners to adjust the trajectory of spacecraft exploring the solar system.

The same concept applies to light as it passes by massive objects like galaxy clusters and is the principle behind the gravitational lense. The first evidence of light being deflected by a massive object was performed in 1919 by Arthur Eddington and Frank Watson Dyson during a total solar eclipse. Gravitational lenses entered the scene 60 years later when they were first observed in 1979 by Dennis Walsh, Bob Carswell, and Ray Weymann using the 2.1m telescope at the Kitt Peak National Observatory.

Part 1

In a fascinating paper authored by Toth and posted to the arXiv preprint server, he explores the possibility that multiple gravitational lenses might provide extra amplification of light to provide a communication bridge between distant civilizations.

In a conventional gravitational lens, a large mass—such as a cluster of galaxies—sits between a more distant object and the Earth. As the light travels from the distant object, it is bent around the galaxy cluster, providing a lensing effect to astronomers on Earth, allowing them to a) study the distribution of matter in the lensing cluster but also to observe the more distant object a little more easily. Toth proposes that, just like a conventional telescope that uses multiple lenses, a multiple gravitational lens could provide even more amplification than a single system.

Toth explores combinations of multiple gravitational lenses using a variety of methods but focuses (sorry) attention on a two-lens system (so-called gravitational lens bridge), which is aligned along the central axis of the system, but found no advantages and no additional signal amplification over the results from a single lens system. In addition, photon mapping techniques were applied with the same outcome; a double-lens system offers no advantage over a single-lens system.

Applying the wave theory of light to the same two-lens system revealed the same results, but using computer graphics to perform ray tracing (which cannot be used to estimate amplification) can help to highlight visual features other techniques would be unable to produce. Using this approach, it suggested a two-lens system would produce two concentric Einstein rings; however, they would be very difficult to detect in real-world scenarios. In summary, then, a fascinating concept, especially the possibility of using a lens bridge for communication with distant civilizations, but the results are less than promising. Yes, there may well be double gravitational lenses, but as this paper shows, it is unlikely we will be able to detect them for now and sadly I suspect the idea of using them as a long-distance cosmic telephone will for now remain science fiction.

 Viktor T. Toth, Non-coplanar gravitational lenses and the "communication bridge", arXiv (2023). DOI: 10.48550/arxiv.2310.15957

Part 2

How Could a Piece of the Moon Become a Near-Earth Asteroid? Researchers Have an Answer

A team of astronomers has found a new clue that a recently discovered near-Earth asteroid, Kamo`oalewa, might be a chunk of the moon. They hypothesized that the asteroid was ejected from the lunar surface during a meteorite strike–and they found that a rare pathway could have allowed Kamo`oalewa to get into orbit around the sun while remaining close to the orbits of the Earth and the Moon.

Scientists Just Discovered a New Human Sense of Touch

A new study reveals a previously undiscovered way that we can feel light touches: directly through our hair follicles. Before now, it was thought that only nerve endings in the skin and around the hair follicles could transmit the sensation.

Researchers used an RNA sequencing process to find that cells in part of the hair follicle called the outer root sheath (ORS) had a higher percentage of touch-sensitive receptors than equivalent cells in the skin.

Touch-sensing nerve cells are known as mechanoreceptors. They're the reason we can feel everything from a light breeze to a firm press. In this case, the hair follicle cells were interacting specifically with low-threshold mechanoreceptors (LTMRs), capable of feeling gentle touches.

https://www.science.org/doi/10.1126/sciadv.adh3273

Biomimetic melanin heals skin injuries from sunburn and chemical burns

Melanin in humans and animals provides pigmentation to the skin, eyes and hair. The substance protects your cells from sun damage with increased pigmentation in response to sunlight—a process commonly referred to as tanning. That same pigment in your skin also naturally scavenges free radicals in response to damaging environmental pollution from industrial sources and automobile exhaust fumes.

Imagine a skin cream that heals damage occurring throughout the day when your skin is exposed to sunlight or environmental toxins. That's the potential of a synthetic, biomimetic melanin developed by scientists.

In a new study,  scientists show that their synthetic melanin, mimicking the natural melanin in human skin, can be applied topically to injured skin, where it accelerates wound healing. These effects occur both in the skin itself and systemically in the body. When applied in a cream, the synthetic melanin can protect skin from sun exposure and heals skin injured by sun damage or chemical burns, the scientists said.

The technology works by scavenging free radicals, which are produced by injured skin such as a sunburn. Left unchecked, free radical activity damages cells and ultimately may result in skin aging and skin cancer.

Topical Application of Synthetic Melanin Promotes Tissue Repair, npj Regenerative Medicine (2023).

Research shows one sleepless night can rapidly reverse depression for several days

Most people who have pulled an all-nighter are all too familiar with that "tired and wired" feeling. Although the body is physically exhausted, the brain feels slap-happy, loopy and almost giddy.

Now neurobiologists are the first to uncover what produces this punch-drunk effect. In a new study, researchers induced mild, acute sleep deprivation in mice and then examined their behaviors and brain activity. Not only did dopamine release increase during the acute sleep loss period, synaptic plasticity also was enhanced—literally rewiring the brain to maintain the bubbly mood for the next few days.

These new findings could help researchers better understand how mood states transition naturally. It also could lead to a more complete understanding of how fast-acting antidepressants (like ketamine) work and help researchers identify previously unknown targets for new antidepressant medications.

Chronic sleep loss is well studied, and it's uniformly detrimental effects are widely documented and it is not good.Scientists long have known that acute perturbations in sleep are associated with altered mental states and behaviors. Alterations of sleep and circadian rhythms in patients, for example, can trigger mania or occasionally reverse depressive episodes.

 But brief sleep loss—like the equivalent of a student pulling an all-nighter before an exam—is less understood. Now researchers found that sleep loss induces a potent antidepressant effect and rewires the brain. This is an important reminder of how our casual activities, such as a sleepless night, can fundamentally alter the brain in as little as a few hours.

Mingzheng Wu et al, Dopamine pathways mediating affective state transitions after sleep loss, Neuron (2023). DOI: 10.1016/j.neuron.2023.10.002. www.cell.com/neuron/fulltext/S0896-6273(23)00758-4

**

Wildfire plumes deposit ash on seawater, fueling growth of phytoplankton

A team of marine biologists has found that large wildfires can deposit large amounts of ash on seawater, fueling the growth of phytoplankton. In their study, reported in the journal Proceedings of the Royal Society B: Biological Sciences, the group tested the impact of ash from a major wildfire on seawater samples in their lab.

Prior research has shown that large forest fires and wildfires produce a large amount of ash that remains in the air for a period of time before falling. Prior research has also found that when ash falls onto land, the result is usually positive—the ash serves as a form of fertilizer. Unfortunately, the same cannot be said for rivers and lakes—the sudden infusion of large amounts of toxic metals can kill fish and other aquatic creatures such as mollusks. For larger bodies of water, it can lead to algal blooms that remove oxygen from the water, resulting in dead zones. For this new study, the research team tracked wildfire plumes over the ocean. They collected samples of ash generated by the Thomas Fire in 2017 and brought them back to their lab for testing. The team mixed samples with fresh seawater in a jar. After a few days, they found that the ash/water solution contained high levels of dissolved nutrients, such as nitrogen and silicic acid. They found it also contained high levels of metals. The researchers then added more seawater to their ash/water solution that also contained microorganisms native to the ocean. They found that after several days, the number of microorganisms was twice as high as it was in a control sample of seawater. They also noted that they did not find any evidence that the ash had a toxic impact on the sea microorganisms. They suggest their work implies that wildfire plumes that settle on the ocean surface can lead to growth of phytoplankton communities.

T. M. Ladd et al, Food for all? Wildfire ash fuels growth of diverse eukaryotic plankton, Proceedings of the Royal Society B: Biological Sciences (2023). DOI: 10.1098/rspb.2023.1817

.

Mysteries of fainting revealed Experiments in mice have identified a specific group of sensory neurons that is responsible for syncope, the brief loss of consciousness during fainting. The cells — called NPY2R vagal sensory neurons — are found in the vagus nerve, which connects the brain to the heart and other organs. Scientists activated these cells in mice that were roaming about, which then fainted within a few seconds. Their pupils dilated, their eyes rolled back and their heart rate, blood pressure and breathing rate all dipped. The team also found that a region of the brain’s hypothalamus is responsible for recovery from fainting.
Part 1

What causes fainting? Scientists finally have an answer

Neurons in the brain stop working very quickly if you deprive them of oxygen or glucose. If you add oxygen again, they’ll simply resume their work and do so just as quickly.

To better understand what happens inside the brain during syncope, the researchers used electrodes to record the activity of thousands of neurons from various brain regions in mice as the animals fainted. Activity decreased in all areas of the brain, except one specific region of the hypothalamus known as the periventricular zone (PVZ).

The authors then blocked the activity of the periventricular zone, and the mice experienced longer fainting episodes. Stimulating the region caused the animals to wake up and start moving again. The team suggests that a coordinated neural network that includes NPY2R VSNs and the PVZ regulates fainting and recovery.

Lovelace, J. W. et al. Nature https://doi.org/10.1038/s41586-023-06680-7 (2023).

https://www.nature.com/articles/s41586-023-06680-7.epdf?sharing_tok...

Part 3

**

Wearable devices may prevent astronauts getting 'lost' in space

Taking space  flight is dangerous. In leaving the Earth's surface, we lose many of the cues we need to orient ourselves, and that spatial disorientation can be deadly. Astronauts normally need intensive training to protect against it. But scientists have now found that wearable devices which vibrate to give orientation cues may boost the efficacy of this training significantly, making spaceflight slightly safer.

Long-duration spaceflight will cause many physiological and psychological stressors, which will make astronauts very susceptible to spatial disorientation. When disoriented, an astronaut will no longer be able to rely on their own internal sensors, which they have depended on for their whole lives.
Part 1

The researchers used sensory deprivation and a multi-axis rotation device to test their vibrotactors in simulated spaceflight, so the senses participants would normally rely on were useless. Could the vibrotactors correct the misleading cues the participants would receive from their vestibular systems, and could participants be trained to trust them?

In total, 30 participants were recruited, of whom 10 received training to balance in the rotation device, 10 received the vibrotactors, and the remaining 10 received both. All participants were shown a video of the rotation device and told how it worked: moving like an inverted pendulum until it reached a crash boundary, unless it was stabilized by a person sitting in the device controlling it with a joystick.

Additional training, for the participants who received it, included tasks that taught participants to disengage from their vestibular sense and rely on the vibrotactors instead of their natural gravitational cues. These tasks involved searching for hidden non-upright balance points, which meant participants had to ignore their desire to align to upright and focus on the vibrotactors.

All participants were given a blindfold, earplugs, and white noise to listen to. Those with vibrotactors had four strapped to each arm, which would buzz when they moved away from the balance point. Each participant took part in 40 trials, aiming to keep the rotation device as close to the balance point as possible.

For half the trials, the rotation device operated on a vertical roll plane. This was considered an Earth analog because participants could use their natural gravitational cues for orientation. During the second half, which acted as a spaceflight analog, the rotation device operated on a horizontal roll plane where those gravitational cues could no longer help.

After each block of trials, participants were asked to rate how disoriented they felt and how much they trusted the vibrotactors. The scientists measured their success by looking at how often they crashed and how well they controlled their balance.
All the groups were initially disoriented in the spaceflight analog. The scientists expected this, because participants could not rely on the natural gravitational cues that they usually use. Nearly all participants reported that they trusted the vibrotactors, but they also reported confusion from conflicts between their internal cues and the vibrotactors.

The participants wearing vibrotactors still performed better than those who only received training. The training-only group crashed more frequently, moved around the balance point more, and accidentally destabilized themselves more often. Receiving the training did help, though. As the trials continued, the group who received both training and vibrotactors performed best.

However, even with training, the participants didn't perform as well as they did in the Earth analog. They may have needed more time to integrate cues from the vibrotactors, or the buzzing from the vibrotactors may not have given a strong enough danger signal.

"A pilot's cognitive trust in this external device will most likely not be enough" . "Instead, the trust has to be at a deeper—almost sub-cognitive—level. To achieve this, specialized training will be required."
Part 2

If the sensors succeed in more extensive trials, the scientists said, the possible applications for spaceflight are many—from helping astronauts land safely on the surface of a planet, to supporting them as they move outside a vehicle in space.

Vibrotactile Feedback as a Countermeasure for Spatial Disorientation, Frontiers in Physiology (2023). DOI: 10.3389/fphys.2023.1249962
Part 3
**

Researchers find evidence of mpox circulating in humans since 2016

A large international team of medical researchers and epidemiologists has found evidence that monkeypox (mpox) has been circulating in humans since 2016. In their study, reported in the journal Science, the group used Bayesian evolutionary analysis of the mpox virus to show that its genomic history includes years of change due to human infections.

Mpox was first identified in the 1950s after an illness struck a group of research monkeys in Denmark. Twenty years later, the first case was detected in a human in Africa. Over the following decades, several cases of the disease were seen in humans and all were attributed to the virus jumping from other mammals.

Then, in 2017, an outbreak occurred in Nigeria and by 2022, it had spread across the globe, demonstrating that the virus had evolved to jump from human to human. In this new effort, the research team took a closer look at the genome of the virus behind mpox to learn more about its evolutionary history, particularly how it relates to human infections. The researchers sequenced the genome of the mpox virus to learn more about its evolutionary history. They found that the clade IIb was the one that had spread around the world. They also noted that it looked different from other strains that had been seen before in Africa.

They found a mutation that had led to the production of an enzyme called APOBEC3, which was found to cause further mutations that alter genome base pairs. It was also found to have come about due to infections in humans. That allowed the team to trace the evolutionary history of the virus as it infected humans—they found such mutations going back to approximately 2016, which strongly suggests that the virus has been transmittable between humans since that year. The research team concludes that there is a strong likelihood of multiple cases of small mpox outbreaks that have not been recognized, allowing the virus to spread under the radar. They further suggest stronger surveillance methods be established because the virus is still mutating rapidly and could become deadlier.

Áine O'Toole et al, APOBEC3 deaminase editing in mpox virus as evidence for sustained human transmission since at least 2016, Science (2023). DOI: 10.1126/science.adg8116

Seeing the unseen: How butterflies can help scientists detect cancer

There are many creatures on our planet with more advanced senses than humans. Turtles can sense Earth's magnetic field. Mantis shrimp can detect polarized light. Elephants can hear much lower frequencies than humans can. Butterflies can perceive a broader range of colors, including ultraviolet (UV) light.

Inspired by the enhanced visual system of the Papilio xuthus butterfly, a team of researchers have developed an imaging sensor capable of "seeing" into the UV range inaccessible to human eyes. The design of the sensor uses stacked photodiodes and perovskite nanocrystals (PNCs) capable of imaging different wavelengths in the UV range. Using the spectral signatures of biomedical markers, such as amino acids, this new imaging technology is even capable of differentiating between cancer cells and normal cells with 99% confidence.

Researchers have taken inspiration from the visual system of butterflies, who are able to perceive multiple regions in the UV spectrum, and designed a camera that replicates that functionality. They did this by using novel perovskite nanocrystals, combined with silicon imaging technology, and this new camera technology can detect multiple UV regions.

UV light is electromagnetic radiation with wavelengths shorter than that of  visible light(but longer than X-rays). We are most familiar with UV radiation from the sun and the dangers it poses to human health. UV light is categorized into three different regions—UVA, UVB and UVC— based on different wavelength ranges. Because humans cannot see UV light, it is challenging to capture UV information, especially discerning the small differences between each region.

Butterflies, however, can see these small variations in the UV spectrum, like humans can see shades of blue and green.UV light is incredibly difficult to capture, it just gets absorbed by everything, and butterflies have managed to do it extremely well.

Part 1

Humans have trichromatic vision with three photoreceptors, where every color perceived can be made from a combination of red, green and blue. Butterflies, however, have compound eyes, with six (or more) photoreceptor classes with distinct spectral sensitivities. In particular, the Papilio xuthus, a yellow, Asian swallowtail butterfly, has not only blue, green and red, but also violet, ultraviolet and broadband receptors. Further, butterflies have fluorescent pigments that allow them to convert UV light into visible light which can then be easily sensed by their photoreceptors. This allows them to perceive a broader range of colors and details in their environment.

Beyond the increased number of photoreceptors, butterflies also exhibit a unique tiered structure in their photoreceptors. To replicate the UV sensing mechanism of the Papilio xuthus butterfly, the UIUC team has emulated the process by combining a thin layer of PNCs with a tiered array of silicon photodiodes.

PNCs are a class of semiconductor nanocrystals that display unique properties similar to that of quantum dots—changing the size and composition of the particle changes the absorption and emission properties of the material. In the last few years, PNCs have emerged as an interesting material for different sensing applications, such as solar cells and LEDs. PNCs are extremely good at detecting UV (and even lower) wavelengths that traditional silicon detectors are not. In the new imaging sensor, the PNC layer is able to absorb UV photons and re-emit light in the visible (green) spectrum which is then detected by the tiered silicon photodiodes. Processing of these signals allows for mapping and identification of UV signatures.

Part 2

There are various biomedical markers present in cancerous tissues at higher concentrations than in healthy tissues—amino acids (building blocks of proteins), proteins, and enzymes. When excited with UV light, these markers light up and fluoresce in the UV and part of the visible spectrum, in a process called autofluorescence. 

Because cancer and healthy cells have different concentrations of markers and therefore different spectral signatures, the two classes of cells can be differentiated based on their fluorescence in the UV spectrum. The team evaluated their imaging device on its ability to discriminate cancer-related markers and found that is capable of differentiating between cancer and healthy cells with 99% confidence.

One of the biggest challenges is knowing how much tissue to remove to ensure clear margins and such a sensor can help facilitate the decision making process when a surgeon is removing a cancerous tumor.

"This new imaging technology is enabling us to differentiate cancerous versus healthy cells and is opening up new and exciting applications beyond just health.

Cheng Chen et al, Bioinspired, vertically stacked, and perovskite nanocrystal–enhanced CMOS imaging sensors for resolving UV spectral signatures, Science Advances (2023). DOI: 10.1126/sciadv.adk3860. www.science.org/doi/10.1126/sciadv.adk3860

Part 3

How can we avoid drinking forever chemicals and arsenic?

per- and polyfluoroalkyl substances, also known as PFAS or forever chemicals, which are used to protect clothing, cookware, cosmetics, and other products from water, grease, or oil. But those chemicals can leach out of those goods to haunt our food, air, plants, and drinking water. So far, scientists have found that PFAS exposure could lead to liver and immune system damage, increased risk of kidney or testicular cancer, birth defects, and other health and environmental problems.

And one of the most common ways to ingest these chemicals is through contaminated water.

PFAS are typically present at really, really low concentrations. But they can be carcinogenic even at low concentrations.

Luckily, we can extract PFAS and other unwanted contaminants, like arsenic or calcium, from our water using a process called ion exchange. And soon, removing PFAS will not be optional. In June 2023, the Environmental Protection Agency announced its plan to require water utilities to reach near-zero levels of PFAS in drinking water. That means many water treatment facilities will need to upgrade their systems to target this insidious chemical.

And ion exchange technologies are some of the only selective separation technologies we have that can get these forever chemicals out of water.

Source: US National Renewable Energy Laboratory  

Cancer trial results show power of weaponized antibodies

A living bandage: Wound dressing uses probiotic bacteria to combat biofilms

Chronic wounds: If an injury has not healed after four weeks, there is a wound healing disorder. Sometimes, seemingly harmless tissue damage can develop into a permanent health problem or even blood poisoning.

Treatment is particularly difficult because germs that know how to protect themselves perfectly settle here. These bacteria form a biofilm, a stubborn compound of various pus pathogens. For their own protection, they produce a layer of mucus with which they attach themselves to surfaces. Antibiotics or disinfectants reach their limits because they cannot get to the dangerous germs.

A research team  is currently developing a wound dressing that uses "good" probiotic bacteria to combat biofilms. The researchers recently published a proof of concept in the journal Microbes and Infection.

They used living probiotic bacteria for the new dressing. They are found in healthy intestinal flora and play a major role in the production of foods such as yogurt and cheese. The used probiotic lactobacilli are biocompatible and create an acidic environment by producing lactic acid. 

This is intended to push the unfavourable, alkaline pH in chronic wounds in the right, i.e., acidic, direction. In the laboratory experiments, the bacteria were able to induce a strongly acidic pH of 4 in the culture medium. At the same time, the probiotics promoted the migration of human fibroblasts under the investigated conditions.

Finally, the beneficial bacteria were integrated into a dressing that protects chronic wounds from further infection. This also allowed the living lactobacilli to produce lactic acid in a protected environment. As desired, the dressing released the acidic product into the environment in a controlled and steady manner.

In laboratory tests, the dressing material with integrated probiotics was able to completely remove a typical biofilm of skin pathogens in a culture dish. The question now was: Does the dressing containing beneficial bacteria also pass the test with human skin?

The researchers created artificial wounds with a diameter of two millimeters on small tissue samples and allowed a biofilm of wound pathogen Pseudomonas aeruginosa to grow. In this three-dimensional model of a human skin infection, the probiotics-containing dressing reduced the number of pathogens by 99.999%. In addition, the researchers were able to prove that the probiotics do not harm human skin cells and triggers the production of inflammatory response of the cells.

Zhihao Li et al, Topical application of Lactobacilli successfully eradicates Pseudomonas aeruginosa biofilms and promotes wound healing in chronic wounds, Microbes and Infection (2023). DOI: 10.1016/j.micinf.2023.105176

Plastic waste in rivers may carry dangerous microbes

Plastic litter in rivers might be allowing dangerous pathogens to hitch-hike downstream, a new study published recently found.

The research, which focused on one river, found that dumped plastic, wooden sticks and the water itself were a breeding ground  for communities of microorganisms, potentially providing a reservoir for bacteria and viruses known to cause human diseases and antibiotic resistance.

These findings indicate that plastic  in freshwater bodies may contribute to the transport of potential pathogens and antibiotic resistance genes.

This could have indirect but significant implications for human health.

Rivers are the main way plastic enters the world's oceans, channeling anywhere between 3.5 thousand metric tons to 2.41 million metric tons of the manmade material to the sea annually.

When plastic ends up in water its surface is overrun within minutes by nearby microbes. The researchers submerged samples for a week in the River Sowe in Warwickshire and West Midlands England, downstream from a wastewater treatment plant. They found significant differences in the microbe communities depending on the material sampled.

Vinko Zadjelovic, Microbial hitchhikers harbouring antimicrobial‑resistance genes in the riverine plastisphere, Microbiome (2023). DOI: 10.1186/s40168-023-01662-3. www.biomedcentral.com/articles … 6/s40168-023-01662-3

 Animal-to-human diseases could kill 12 times as much by 2050: Study

Certain diseases transmitted from animals to humans could kill 12 times as many people in 2050 than they did in 2020, researchers have claimed.

Epidemics caused by zoonotic diseases—also known as spillovers—could be more frequent in the future due to climate change and deforestation, experts warned.

The team's analysis looked at historic trends for four particular viral pathogens.

These were filoviruses, which include Ebola virus and Marburg virus, SARS Coronavirus 1, Nipah virus, and Machupo virus, which causes Bolivian hemorrhagic fever.

The study did not include COVID-19, which caused the global pandemic in 2020 and is likely to have originated in bats.

It looked at more than 3,150 outbreaks between 1963 and 2019, identifying 75 spillover events in 24 countries.

The database covered epidemics reported by the World Health Organization, outbreaks occurring since 1963 that killed 50 or more people, and historically significant events including the flu pandemics of 1918 and 1957.

The events caused 17,232 deaths, with 15,771 caused by filoviruses and occurring mostly in Africa.

Researchers said epidemics have been increasing by almost 5% every year between 1963 and 2019, with deaths up by 9%.

"If these annual rates of increase continue, we would expect the analyzed pathogens to cause four times the number of spillover events and 12 times the number of deaths in 2050 than in 2020," they added.

Researchers also suggested the figures are likely to be an underestimate due to the strict inclusion criteria for the pathogens in the analysis and the exclusion of COVID-19. They said the evaluation of evidence suggests recent epidemics sparked by zoonotic spillovers "are not an aberration or random cluster" but follow "a multi-decade trend in which spillover-driven epidemics have become both larger and more frequent." The team added that "urgent action is needed to address a large and growing risk to global health" based on historical trends.

Amanda Jean Meadows et al, Historical trends demonstrate a pattern of increasingly frequent and severe spillover events of high-consequence zoonotic viruses, BMJ Global Health (2023). DOI: 10.1136/bmjgh-2023-012026

No appetite for vegetarian diet to help the planet, finds study

Social media users believe reducing and eliminating meat intake is ineffective in addressing climate change and reported low willingness to engage in either action, according to a new study.

This is despite recent global reports revealing the strong links between the animal agricultural industry and greenhouse gas emissions, as well as the idea that what people put on their plate is an important piece in confronting the climate crisis. The study, published in Sustainability, asked more than 700 Facebook account users, between the ages of 18 to 84, about their beliefs on climate change, the impact of meat consumption on the environment and meat intake.

Although past research has shown that animal agriculture contributes significantly to greenhouse gas emissions, the participants believed reducing and eliminating meat intake to be some of the least effective actions against climate change.

This study highlighted an increased awareness that meat-eating has environmental impacts, yet its impact was rated significantly less than other pro-environmental behaviors, such as using public transport, recycling, and renewable energy.

The findings of this study can help shed light on the disconnect between research and public knowledge and subsequently, how to bridge this gap. Sci-com? Yes!

 Ashley Rattenbury et al, Perceptions of the Benefits and Barriers to Vegetarian Diets and the Environmental Impact of Meat-Eating, Sustainability (2023). DOI: 10.3390/su152115522

Dose response: The basics

An implantable wireless cardiac pacemaker

Cardiac pacemakers are battery-dependent, where the pacing leads are prone to introduce valve damage and infection. In addition, complete pacemaker retrieval is necessary for battery replacement. Despite the presence of a wireless bioelectronics device to pace the epicardium, surgeons still need to implant the device via thoracotomy, an invasive surgical procedure in health care that necessitates wound healing.

A research team of scientists in bioengineering, microbiology, and cardiology devised a biocompatible wireless microelectronics device to form a microtubular pacemaker for intravascular implantation and pacing. 

The pacemaker provided effective pacing to restore cardiac contraction from a non-beating heart in a porcine animal model. The microtubular pacemaker paves the way for the minimally-invasive implantation of leadless and battery-free microelectronics for health care and cardiac pace restoration.

Shaolei Wang et al, A self-assembled implantable microtubular pacemaker for wireless cardiac electrotherapy, Science Advances (2023). DOI: 10.1126/sciadv.adj0540

The story of a teenage boy who swallowed 21 disc magnets

Doctors at Guthrie Healthcare System, in Sayre, Pennsylvania, have documented a case of a teenage boy who swallowed 21 disc magnets. In their paper published in BMJ Case Reports, the medical team describes how they found the magnets, removed them, and cared for the boy afterward.

Prior research and anecdotal evidence by doctors and other medical personnel has shown that swallowing magnets can be harmful. Their magnetic field and caustic properties can lead to damage in the digestive tract.

In this new study, the researchers report that a teenage boy was transferred to their facility from another hospital with metal objects of some kind in his stomach. When asked, the boy told the medical staff at both hospitals that he did not know how the objects could have wound up in this stomach. X-rays and a CT scan showed the presence of multiple metallic items. An initial procedure involved removing three small discs that had become embedded in the stomach wall using forceps and a surgical net. After removal, the doctors determined that the metal objects were small disc magnets. Three more of the magnets had become embedded in the walls of the large intestine—notably, there were also signs that the wound caused by the discs had led to decay of intestinal tissue. Further investigation showed that there were another 15 magnets embedded in various parts of both the large and small intestine, most of which required surgery for removal.

The surgeon noted that some of the magnets had begun to create holes in the intestinal walls. The case study team notes that the dangers of ingesting magnets are well known. Instead of passing harmlessly through the digestive tract, they become embedded in the walls of organs, causing tissue decay.

They also note that that the boy in their case study was lucky in the sense that pain caused by the magnets had brought him to the hospital before any of the magnets had time to burrow all the way through organ walls. Leakage of material from the stomach or intestines into other parts of the body can be deadly due to infection.

Simona Maksimyan et al, Clinical course and management of an unknown multiple-magnet ingestion in a teenage male, BMJ Case Reports (2023). DOI: 10.1136/bcr-2023-256418

How global warming shakes the Earth: Seismic data show ocean waves gaining strength as the planet warms

As oceans waves rise and fall, they apply forces to the sea floor below and generate seismic waves. These seismic waves are so powerful and widespread that they show up as a steady thrum on seismographs, the same instruments used to monitor and study earthquakes.

That wave signal has been getting more intense in recent decades, reflecting increasingly stormy seas and higher ocean swell. In a new study in the journal Nature Communications, researchers tracked that increase around the world over the past four decades. These global data, along with other ocean, satellite and regional seismic studies, show a decadeslong increase in wave energy that coincides with increasing storminess attributed to rising global temperatures.

 Richard C. Aster et al, Increasing ocean wave energy observed in Earth's seismic wavefield since the late 20th century, Nature Communications (2023). DOI: 10.1038/s41467-023-42673-w

The cell's 'read–write' mechanism: Researchers uncover how instructions for gene expression are relayed

The "read–write" mechanism by which cells replicate and use chemical instructions for expressing genes has been uncovered by  researchers. The quality and quantity of gene expression correlates not only with instructions by transcription factors but also with chemical modifications to the various histone proteins, which provide a scaffold for DNA in the chromosomes.

Scientists have long argued whether these modifications to histones are the epigenetic cause for activating gene expression. And, if that is the case, how they activate gene expression and are maintained during the process of mitosis, in which a cell divides into two daughter cells.

Researchers now have developed an experimental technology that allowed them to generate histones with acetylations at defined sites. They then monitored how p300/CBP interacts with and acetylates a nucleosome containing these selectively acetylated human histones.

The researchers found that p300/CBP recognizes and binds to specific acetylation marks on the H3–H4 complex. The enzyme then replicates acetylation marks to unacetylated sites of H3–H4, while also transcribing them from H3–H4 to H2B–H2A within the same nucleosome. Since this newly acetylated H2B–H2A complex is more likely to be stripped from the nucleosome, a model emerges in which it finally instructs which genes to be transcribed by the cellular transcription machinery. These results provide an unprecedented glimpse into how p300/CBP inherits acetylation marks to newly divided cells and utilizes those marks epigenetically for gene expression.

Masaki Kikuchi et al, Epigenetic mechanisms to propagate histone acetylation by p300/CBP, Nature Communications (2023). DOI: 10.1038/s41467-023-39735-4

Contraceptive Pills Have a strange Effect on The Fear-Promoting Area of The Brain

Scientists have found a possible link between using oral contraceptives and changes in parts of the brain that process fear. The findings may help explain fear-related mechanisms that disproportionately affect women. Hormonal changes during a menstrual cycle are currently understood to affect the fear circuitry in the brain. So researchers looked into the effects of combined oral contraceptive (COC) use to learn more about the relationship between sex hormones our bodies make naturally and synthetic versions of those hormones. This effect appeared to be reversible. A comparison with those who stopped using contraceptives or those who had never used contraceptives indicated this physiological change didn't seem to be lasting. To be clear, these are just associations, and there are no known negative effects linked to the change in size of certain brain regions. But the authors think it could be worth exploring further. This part of the prefrontal cortex is thought to sustain emotion regulation, such as decreasing fear signals in the context of a safe situation. The result may represent a mechanism by which combined OCs could impair emotion regulation in women. Researchers found levels of both natural and synthetic sex hormones were linked to changes in the size and thickness of the vmPFC compared to the same anatomy in men. However, only women who were currently using oral contraceptives had a thinner vmPFC than that in men. The researchers also found the structure in a fear-promoting brain region – the dorsal anterior cingulate cortex (dACC) – varied between men and women. This was noticeable regardless of COC use, emphasizing one way naturally-produced sex hormones can influence brain structure. Given the results that men have smaller dACC volume than women and thicker vmPFC than COC users, these findings may represent structural vulnerabilities to psychopathologies that predominantly affect women.

https://www.frontiersin.org/articles/10.3389/fendo.2023.1228504/full

Researchers identify brain network that is uniquely activated through injection vs. oral drug use

Understanding the brain mechanisms that underlie addiction is crucial for informing prevention interventions, developing new therapies for substance use disorders, and addressing the overdose crisis.

Results from a new clinical trial suggest that a group of brain regions known as the "salience network" is activated after a drug is taken intravenously, but not when that same drug is taken orally.

When drugs enter the brain quickly, such as through injection or smoking, they are more addictive than when they enter the brain more slowly, such as when they are taken orally. However, the brain circuits underlying these differences are not well understood. This study offers new information that helps explain what may be causing this difference.

People who smoke or inject drugs—two methods that deliver drugs to the brain quickly—often report doing so to get faster relief from withdrawal or to experience euphoria more quickly. However, drug smoking and injection are associated with developing a substance use disorder more quickly than taking drugs orally or by insufflation (e.g., snorting).

In addition, injecting drugs is also associated with higher rates of infectious diseases and overdose. To better understand how route of drug administration impacts the brain's response to the drug, researchers conducted a double-blind, randomized, counterbalanced clinical trial using simultaneous PET/fMRI imaging.

Part 1

This study showed that when participants received methylphenidate orally, the rate of dopamine increases peaked more than an hour after administration. Comparatively, when participants received an intravenous injection of methylphenidate, the rate of dopamine increases peaked much faster—within 5 to 10 minutes of the administration.

Through the fMRI, researchers observed that one brain region, the  ventromedial prefrontal cortex,  was less active after both oral and intravenous administration of the study drug. However, two brain regions, the dorsal anterior cingulate cortex and the insula, which are part of the brain's salience network, were activated only after receiving the injection of methylphenidate, the more addictive route of drug administration. These same areas of the brain were not activated after taking methylphenidate orally, the route with lower addiction potential. This finding was consistent among all 20 research participants.

The salience network attributes value to things in our environment and is important for recognizing and translating internal sensations—including the subjective effects of drugs. This research adds to a growing body of evidence documenting the important role that the salience network appears to play in substance use and addiction. For instance, studies have shown that people who experience damage to the insula, part of the brain's salience network, can have a complete remission of their addiction.

 P Manza, et al. Neural circuit selective for fast but not slow dopamine increases in drug reward, Nature Communications (2023). DOI: 10.1038/s41467-023-41972-6. www.nature.com/articles/s41467-023-41972-6

Part 2

 Willow bark extract has broad-spectrum antiviral effect

We need safe, sustainable antiviral options to treat the outbreaks of the future. Scientists  have now shown that an extract of willow bark—a plant that has already provided several medicines, including the precursor to modern aspirin—has a broad-spectrum antiviral effect in cell sample experiments.

The extract worked both on enveloped coronaviruses, which cause colds as well as COVID-19, and non-enveloped enteroviruses, which cause infections such as flu and meningitis. There are no clinically approved drugs that work against enteroviruses directly, so this extract could be a future game-changer.

The scientists had previously tested willow bark extract on enteroviruses, and found it was highly successful. In this new study, they expanded the remit of their research to look at additional kinds of virus and to try to understand the mechanism of the extract's action.

Willow (Salix spp.) bark hot extracts inhibit both enveloped and nonenveloped viruses: study on its anti-coronavirus and anti-enterovirus activities, Frontiers in Microbiology (2023). DOI: 10.3389/fmicb.2023.1249794

Cheetahs become more nocturnal on hot days. Climate change may trigger fights among predators

Changing temperatures can impact the behavior patterns of large carnivore species and also the dynamics among species.

Cheetahs are usually daytime hunters, but the speedy big cats will shift their activity toward dawn and dusk hours during warmer weather, a new study finds.

Unfortunately for endangered cheetahs, that sets them up for more potential conflicts with mostly nocturnal competing predators such as lions and leopards, say the authors of research published recently in the journal Proceedings of the Royal Society B.

While cheetahs only eat fresh meat, lions and leopards will sometimes opportunistically scavenge from smaller predators.

Lions and leopards normally kill prey themselves, but if they come across a cheetah's kill, they will try to take it. The cheetahs will not fight the larger cats, they will just leave.

Hunting at different times of the day is one long-evolved strategy to reduce encounters between the multiple predator species. But the new study found that on the hottest days, when maximum daily temperatures soared to nearly 45 degrees Celsius (113 degrees Fahrenheit), cheetahs became more nocturnal—increasing their overlapping hunting hours with rival big cats by 16%.

There's a greater chance for more unfriendly encounters and less food for the cheetahs because of global warming. 

Kasim Rafiq et al, Increasing ambient temperatures trigger shifts in activity patterns and temporal partitioning in a large carnivore guild, Proceedings of the Royal Society B: Biological Sciences (2023). DOI: 10.1098/rspb.2023.1938

Engineered 'living materials' could help clean up water pollution one day

Water pollution is a growing concern globally, with research estimating that chemical industries discharge 300–400 megatonnes (600–800 billion pounds) of industrial waste into bodies of water each year. As a team of materials scientists, we're working on an engineered "living material" that may be able to transform chemical dye pollutants from the textile industry into harmless substances.

Water pollution is both an environmental and humanitarian issue that can affect ecosystems and human health alike. We're hopeful that the materials we're developing could be one tool available to help combat this problem.
The "engineered living material" scientists have been working on contains programmed bacteria embedded in a soft hydrogel material.
The hydrogel that forms the base of the material has similar properties to Jell-O—it's soft and made mostly of water. Our particular hydrogel is made from a natural and biodegradable seaweed-based polymer called alginate, an ingredient common in some foods.

The alginate hydrogel provides a solid physical support for bacterial cells, similar to how tissues support cells in the human body. We intentionally chose this material so that the bacteria we embedded could grow and flourish.
Part 1

This is how the scientists described their work:

After we prepared the hydrogel, we embedded photosynthetic—or sunlight-capturing—bacteria called cyanobacteria into the gel.

The cyanobacteria embedded in the material still needed to take in light and carbon dioxide to perform photosynthesis, which keeps them alive. The hydrogel was porous enough to allow that, but to make the configuration as efficient as possible, we 3D-printed the gel into custom shapes—grids and honeycombs. These structures have a higher surface-to-volume ratio that allow more light, CO₂ and nutrients to come into the material.
Like all other bacteria, cyanobacteria has different genetic circuits, which tell the cells what outputs to produce. Our team genetically engineered the bacterial DNA so that the cells created a specific enzyme called laccase.

The laccase enzyme produced by the cyanobacteria works by performing a chemical reaction with a pollutant that transforms it into a form that's no longer functional. By breaking the chemical bonds, it can make a toxic pollutant nontoxic. The enzyme is regenerated at the end of the reaction, and it goes off to complete more reactions.

 Debika Datta et al, Phenotypically complex living materials containing engineered cyanobacteria, Nature Communications (2023). DOI: 10.1038/s41467-023-40265-2

Blood cancer treatment could be transformed by discovery

Engineered yeast breaks new record: a genome with over 50% synthetic DNA

Scientists have created a strain of brewer’s yeast (Saccharomyces cerevisiae) whose genome is more than half synthetic. Seven-and-a-half chromosomes were synthesized or stitched together in the laboratory. To make sure the genome was stable, biologists removed repetitive regions of DNA and sequestered all genes for transfer RNAs — essential for protein synthesis — in a single ‘neochromosome’. It’s a milestone for the Sc2.0 consortium, whose aim is to create yeast with a fully synthetic genome.

https://www.sciencedirect.com/science/article/pii/S0092867423011303...

https://www.cell.com/cell-genomics/fulltext/S2666-979X(23)00273-2?utm_source=Live+Audience&utm_campaign=3a61cb3609-briefing-dy-20231109&utm_medium=email&utm_term=0_b27a691814-3a61cb3609-50323416

Using bacteria to make lunar soil more fertile

A team of agronomists and biotechnicians  has found that adding bacteria to simulated lunar regolith increased the amount of phosphate in the soil for use by plants. In their study, published in the journal Communications Biology, the group added three types of bacteria to samples of volcanic material and then tested them for acidity and their ability to grow plants.

As several countries make plans to send humans back to the moon, they must address several issues—one of the most basic is figuring out a way to feed people working there for an extended period of time. The obvious solution is for workers to grow their own food. But that presents problems, as well, such as how to transport soil for growing edible plants from Earth to the moon.

Some have suggested that moon soil, known as lunar regolith, might be treated to make it amenable to plant growth. Last year, a team in the U.S. showed that it is possible to grow plants in lunar regolith by growing a small number of weeds called thale cress in real lunar soil samples. That test showed that lunar soil can work, but not well enough for plants to mature and produce food. In this new study, the research team found that adding microbes to lunar soil can improve its ability to host plant life. To test the possibility of using microbes such as bacteria to make lunar regolith more hospitable to plant life, the research team obtained samples of volcanic material from a mountain in China—testing showed it to be a reasonable stand-in for regolith. The researchers then added one of three types of bacteria to three test pots filled with the volcanic material: Pseudomonas fluorescens, Bacillus megaterium and Bacillus mucilaginosus. After cultivating the bacteria in the soil samples, the researchers tested the samples to see the effects. They found that the addition of all three types of bacteria had made the soil samples more acidic, which resulted in reducing the pH level of the soil. That dissolved the insoluble phosphate-containing minerals in the soil, which released phosphorus, making it available for plants.

Yitong Xia et al, Phosphorus-solubilizing bacteria improve the growth of Nicotiana benthamiana on lunar regolith simulant by dissociating insoluble inorganic phosphorus, Communications Biology (2023). DOI: 10.1038/s42003-023-05391-z

Relieving stress in insulin-producing cells protects against type 1 diabetes

Removing a gene that manages stress within insulin-producing beta cells draws helpful attention from the immune system, protecting mice predisposed to type 1 diabetes from developing the disease, a new  study shows.

The study also found that changes discovered in the modified mouse beta cells are also present in human beta cells that manage to survive the widespread beta-cell death that characterizes type 1 diabetes.

This gives the researchers hope that their findings, published in the journal Cell Metabolism, may point to a potential new treatment that could be administered very early in the development of diabetes. 

When we eat, our beta cells produce about 1 million molecules of insulin every minute to help maintain normal blood glucose levels. That is a big and stressful job, especially for a part of these beta cells called the endoplasmic reticulum.

The endoplasmic reticulum is like the cell's warehouse staff. It folds the insulin protein molecules that a beta cell produces, packing them for shipping to other parts of the body. If something goes wrong with the protein folding process, the shipping process backs up or even stops, stressing the endoplasmic reticulum. A stress-response gene called Atf6 perks up when a cell is struggling with unfolded proteins. But if Atf6 can't resolve the protein-folding problem, prolonged stress will eventually kill the cell.

Scientists bred a line of diabetes-predisposed mice without the Atf6 gene in their beta cells. Instead of meeting their typical fate, those mice were protected from diabetes. Analysis of the genes expressed by their beta cells suggested the cells entered a state called senescence far ahead of schedule.

Senescence is a period of the cell's life cycle in which it stops dividing and halts other normal cellular business. Senescing cells can cause problems for neighboring cells by releasing inflammatory messaging molecules that trigger an immune system response.

When researchers removed—knocked-out—the Atf6 gene in the beta cells in the pancreas of their mouse model of type 1 diabetes, and they did not become diabetic. Instead of dying off, these cells unexpectedly appear to go into an early senescence state that initiated a beneficial immune response and helped the cells survive an autoimmune attack.

DNA damage, stress and aging can kick off senescence, which can draw an immune system response that cleans up the senescent cells. If the immune system fails to clear these cells, they accumulate and cause chronic inflammation and disease.

The beta cells without Atf6 exhibit transient senescence and start releasing this group of proteins, including leukemia inhibitory factor, or LIF, that recruits protective immune cells called M2 macrophages.

Part 1

Even more exciting is how closely the new study's results in mice appear to be reflected in human cells.

With a blood test, doctors can identify people who are at high-risk of developing type 1 diabetes months in advance of the death of their beta cells.

That may be a perfect timeframe for a treatment based on pharmacological inhibition of Atf6 or induction of LIF and other secreted proteins. If we can get there in time to protect these cells with transient senescence, the onset of diabetes might be prevented.

Hugo Lee et al, Stress-induced β cell early senescence confers protection against type 1 diabetes, Cell Metabolism (2023). DOI: 10.1016/j.cmet.2023.10.014

Part 2

Earth's Moon: Why One Side Always Faces Us

Astronomers find dozens of massive stars fleeing the Milky Way

The Milky Way can't hold onto all of its stars. Some of them get ejected into intergalactic space and spend their lives on an uncertain journey. A team of astronomers took a closer look at the most massive of these runaway stars to see what they could find out how they get ejected.

When astronomers observe a field of stars in the Milky Way, one of the things they measure is the velocity distribution. The overall velocity distribution of the stellar population reflects the rotation of the galaxy. And when a star isn't harmonized with the galaxy's rotation, it catches astronomers' attention.

A team of astronomers working with two catalogues of massive stars found a whole bunch of stars moving differently than the galaxy. They're runaway stars that are on their way out of the galaxy.

Nobody knows how many runaway stars are on their way out of our galaxy, but astronomers keep finding more of them. Some estimates say there are 10 million runaway stars fleeing the Milky Way, but we don't know for sure. It may depend on the mechanism that drives them away, and that's something astrophysicists don't fully understand. A new study aims to shed some light on the runaway star phenomenon by looking specifically at massive stars.

A relevant fraction of massive stars are runaway stars. These stars move with a significant peculiar velocity with respect to their environment.

Massive early-type OB stars are the most luminous stars in the Milky Way. OB stars are not only massive and young, they're extremely hot. They form in loosely organized groups with one another called OB associations. Because they're young and hot, they don't last long. They're important in astronomy because they're so massive and energetic and because many of them explode as supernovae. That's why there are specific catalogues dedicated to them.

Part 1

Why do massive stars make up such a high proportion of runaway stars? There are two competing theories that attempt to explain runaway stars, and both involve massive stars. One is the dynamical ejection scenario (DES), and the other is the binary supernova scenario (BSS).

OB stars often form in binary pairs. In the BSS, one star explodes as a supernova, and the explosion kicks the other star. If the situation is right, the surviving star is given enough energy in the right direction that it can escape from its bond with its partner, which is now a neutron star or a black hole. It can also escape the gravitational pull of the Milky Way. If that happens, it begins its long journey into intergalactic space.

In the DES, there's no dramatic supernova explosion. Instead, a star in a compact, densely packed region experiences gravitational interactions with other stars. Encounters between binary and single stars can produce runaways, and so can encounters between two binary pairs. The OB associations where O-type and B-type stars tend to form are the types of dense environments that can trigger runaway stars. Since most of these stars are massive, most of the runaway stars are, too.

Scientists have been wondering about the two scenarios and debating them for decades. Both scenarios can produce stars with enough velocity to escape the galaxy. In studying their sample of 175 runaway stars, the researchers found that their data favors one explanation over the other.

The higher percentages and higher velocities found for O-type compared to Be-type runaways underline that the dynamical ejection scenario is more likely than the binary supernova scenario.

The percentages of spectral types represented in runaway stars help explain their conclusion. 25% of the O-type stars in their sample are runaways versus 5% of the Be-type. Other studies have come up with different numbers, but as the researchers point out, there is agreement in the sense that the percentage of runaway O stars is significantly higher than for B or Be stars.

Previous research shows that O-type runaway stars have higher velocities than B and Be-type stars. Previous research also shows that dynamical ejection often results in faster, more massive runaways than the binary supernova scenario. 

M. Carretero-Castrillo et al, Galactic runaway O and Be stars found using Gaia DR3, Astronomy & Astrophysics (2023). DOI: 10.1051/0004-6361/202346613. On arXiv: DOI: 10.48550/arxiv.2311.01827

Part 2

**

World's First Entire Eye Transplant

A team of surgeons in New York has performed the world's first transplant of an entire eye in a procedure widely hailed as a medical breakthrough, although it isn't yet known whether the man will ever see through the donated eye. The groundbreaking surgery involved removing part of the face and the whole left eye – including its blood supply and optic nerve – of a donor and grafting them onto a lineworker from Arkansas who survived a 7,200-volt electric shock in June 2021.

Aaron James, 46, suffered extensive injuries including the loss of his left eye, his dominant left arm above the elbow, his nose and lips, front teeth, left cheek area and chin.
He was referred to NYU Langone Health, a leading medical center for facial transplants, which carried out the procedure on May 27.

Transplanting an entire eye has long been a holy grail of medical science, and though researchers have had some success in animals – where they have restored partial vision – it's never before been performed in a living person.
The transplanted left eye appears very healthy, said retinal ophthalmologist.
It has a good blood supply, is maintaining its pressure, and is generating an electrical signal, though James is not yet able to see. But the doctors have a lot of hope.
The doctors used bone marrow-derived adult stem cells to promote nerve repair.
Source: News Agencies

How animals get their stripes and spots

Nature has no shortage of patterns, from spots on leopards to stripes on zebras and hexagons on boxfish. But a full explanation for how these patterns form has remained elusive.

Now engineers  have shown that the same physical process that helps remove dirt from laundry could play a role in how tropical fish get their colorful stripes and spots. Their findings were published Nov. 8 in the journal Science Advances.

Biologists have previously shown that many animals evolved to have coat patterns to camouflage themselves or attract mates. While genes encode pattern information like the color of a leopard’s spots, genetics alone do not explain where exactly the spots will develop, for example.

In 1952, before biologists discovered the double helix structure of DNA, Alan Turing, the mathematician who invented modern computing, proposed a bold theory of how animals got their patterns.

Turing hypothesized that as tissues develop, they produce chemical agents. These agents diffuse through tissue in a process similar to adding milk to coffee. Some of the agents react with each other, forming spots. Others inhibit the spread and reaction of the agents, forming space between spots. Turing’s theory suggested that instead of complex genetic processes, this simple reaction-diffusion model could be enough to explain the basics of biological pattern formation.

Surely Turing’s mechanism can produce patterns, but diffusion doesn’t yield sharp patterns.

Where particles  form sharply defined stripes,  the process known as diffusiophoresis plays a role in nature’s pattern formation.

Diffusiophoresis happens when a molecule moves through liquid in response to changes, such as differences in concentrations, and accelerates the movement of other types of molecules in the same environment. While it may seem like an obscure concept to non-scientists, it’s actually how laundry gets clean.

One recent study showed that rinsing soap-soaked clothes in clean water removes the dirt faster than rinsing soap-soaked clothes in soapy water. This is because when soap diffuses out of the fabric into water with lower soap concentration, the movement of soap molecules draws out the dirt. When the clothes are put in soapy water, the lack of a difference in soap concentration causes the dirt to stay in place.

The movement of molecules during diffusiophoresis, as researchers observed in their simulations, always follows a clear trajectory and gives rise to patterns with sharp outlines. To see if it may play a role in giving animals their vivid patterns, researchers ran a simulation of the purple and black hexagonal pattern seen on the ornate boxfish skin using only the Turing equations. The computer produced a picture of blurry purple dots with a faint black outline. Then the team modified the equations to incorporate diffusiophoresis. The result turned out to be much more similar to the bright and sharp bi-color hexagonal pattern seen on the fish.

The research team’s theory suggests that when chemical agents diffuse through tissue as Turing described, they also drag pigment-producing cells with them through diffusiophoresis—just like soap pulls dirt out of laundry. These pigment cells form spots and stripes with a much sharper outline.

 Benjamin Alessio et al, Diffusiophoresis-Enhanced Turing Patterns, Science Advances (2023). DOI: 10.1126/sciadv.adj2457. www.science.org/doi/10.1126/sciadv.adj2457

New antifungal molecule kills fungi without toxicity in human cells, mice

A new antifungal molecule, devised by tweaking the structure of prominent antifungal drug Amphotericin B, has the potential to harness the drug’s power against fungal infections while doing away with its toxicity, researchers  reported in the journal Nature.

Amphotericin B, a naturally occurring small molecule produced by bacteria, is a drug used as a last resort to treat fungal infections. While AmB excels at killing fungi, it is reserved as a last line of defense because it also is toxic to the human patient – particularly the kidneys.

This work is a demonstration that, by going deep into the fundamental science, you can take a billion-year head start from nature and turn it into something that hopefully is going to have a big impact on human health.

These researchers spent years exploring AmB in hopes of making a derivative that can kill fungi without harm to humans. In previous studies, they developed and leveraged a building block-based approach to molecular synthesis and teamed up with a group specializing in molecular imaging tools called solid-state nuclear magnetic resonance. They  uncovered the mechanism of the drug: AmB kills fungi by acting like a sponge to extract ergosterol from fungal cells.

The researchers also found that that AmB similarly kills human kidney cells by extracting cholesterol, the most common sterol in people. The researchers also resolved the atomic-level structure of AmB sponges when bound to both ergosterol and to cholesterol.

Using this structural information along with functional and computational studies, they achieved a significant breakthrough in understanding how AmB functions as a potent fungicidal drug. This provided the insights to modify AmB and tune its binding properties, reducing its interaction with cholesterol and thereby reducing the toxicity.

Part 1