The researchers listed the principles of open wound management as follows:

Moisture balance
Infection prevention
Medical optimization of comorbidities including vascular disease and blood glucose control
They discussed the possibilities of minimizing inflammation, and progression towards active proliferation as a healing response. Several methods in the market aim to detect elevated protease activity for impaired wounds, and apply topical oxygen therapy and ultrasound therapy.
The study outcomes highlighted the need for additional strategies, including healing the chronic wounds at complex and intricate levels. Most advances in intervention target coordinated cellular processes to optimize wound care, however, such methods remain incompletely understood, requiring ongoing research innovations. Researchers described the primary aim of existing commercially available interventional biomaterials to impart fluid exudation, moisture balance, and pressure relief to prevent infection.

The advanced biomaterials in development for interventional healing can mimic extracellular matrix-inspired biophysical cues to regulate immune responses to treat and resolve inflammation. Such advances can be delivered to treat patients at the cellular level, where hydrogel influenced delivery systems can allow the sustained release of stimuli-responsive drug molecules to assist patients in adhering to new therapies. The outcomes can facilitate clinical trials of new drugs and biological products to therapeutically interfere in acute and chronic wounds.
Acute wounds arising from surgical and traumatic events can be treated with bandages to inhibit bleeding and effectively promote healing. Researchers have recently combined adhesive hydrogels with surgical meshes to demonstrate their strong adhesion and flexibility under mechanical stress. The present study described existing advanced wound therapies in the clinical pipeline for wound management, anti-infection and biological intervention. These include advanced anti-scarring and healing-promoting therapies. For example, a cell-penetrating asymmetric interfering RNA delivered as an intradermal injection can target connective tissue growth factor to combat scarring.

New peptide formulas engineered to treat venous leg ulcers and diabetic foot ulcers are currently in phase 1 and 2 clinical trials. Next-generation therapies to treat burns are also in clinical trials. For instance, commercially available NexoBrid is a topical agent made of enzymes isolated from a pineapple plant containing a few proteinases to provide selective and quick removal of damaged/dead tissues within hours of application. Phase 3 clinical trial outcomes have shown the impact of the topical agent on healing tissue areas of interest without adverse serious effects. Several cell-based therapies are also similarly under study for adequate intervention.
Part 2

In this way, the researchers in the present analysis summarized multiple methods of interventional wound care and detailed their mechanisms-of-action in preclinical and clinical environments to treat acute and chronic wounds. These methods focus on highly diverse phases of wound healing, including tight closure of the wound to establish homeostasis and modulate the immune system during inflammation, and cell proliferation alongside remodeling in the area of intervention. The bioengineers and materials scientists hope that future wound dressings may sense the unique environment of an inflicted region to deliver personalized strategies to autonomously regulate drug doses for every patient.

As a strategic plan-of-work for bioengineers, the researchers suggest developing an evidence-based target profile and patenting strategy to effectively translate new wound care products from the bench to the bedside in health care. The industrial translation of standard care requires strong clinical data for emerging methods to survive beyond the bench and positively influence the quality of life of patients.

 Benjamin R. Freedman et al, Breakthrough treatments for accelerated wound healing, Science Advances (2023). DOI: 10.1126/sciadv.ade7007

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Part 3

Ants inflict pain with neurotoxins

Researchers have shown for the first time that some of the world's most painful ant stings target nerves, like snake and scorpion venom. This research is published in Nature Communications.

Investigators discovered the ant neurotoxins while studying the Australian green ant and South American bullet ant which have stings that cause long-lasting pain.

These ant venoms target our nerve cells that send pain signals. Normally, the sodium channels in these sensory neurons open only briefly in response to a stimulus. However,  the ant toxins bind to the sodium channels and cause them to open more easily and stay open and active, which translates to a long-lasting pain signal.

Bullet ant stings can be painful for up to 12 hours and it's a deep drilling pain you feel in your bones with sweating and goosebumps, quite unlike the 10-minute impact of a typical bee sting.

The bullet ant was rated as having the most painful insect sting in the world by the late Dr. Justin Schmidt, an American entomologist who created a pain index of stinging insects.

These neurotoxins which target sodium channels are unique to ants. Ants developed their defensive neurotoxins to fend off predators during the time of the dinosaurs and have since become one of the most successful animal groups on Earth..

Samuel D. Robinson et al, Ant venoms contain vertebrate-selective pain-causing sodium channel toxins, Nature Communications (2023). DOI: 10.1038/s41467-023-38839-1

Data show no evidence that chronic disease treatment efficacies depend on number of comorbidities

Treatment efficacy for a broad range of chronic diseases does not differ depending on patients' comorbidities, according to a new study publishing June 6 in the open access journal PLOS Medicine.

There is often uncertainty about how treatments for single conditions should be applied to people who have multiple chronic conditions (multimorbidity). This confusion stems, in part, from the fact that people with multimorbidity are under-represented in randomized controlled trials, and trials rarely report whether the efficacy of treatment differs by the number of comorbidities or the presence of specific comorbidities.

In the new study, the researchers used existing data from 120 industry-sponsored randomized controlled phase 3 and 4 clinical trials carried out between 1990 and 2017. The dataset included a total of 128,331 participants and spanned 23 common long-term conditions, including asthma, diabetes, hypertension, osteoporosis, and migraine. For each trial as well as each treatment type spanning multiple trials, the team modeled whether there were any interactions between treatment efficacy and comorbidities.

Across trials, the percentage of participants with three or more comorbidities ranged from 2.3% (in allergic rhinitis trials) to 57% (in trials for systemic lupus erythematosus). Overall, the new study found no evidence of comorbidities modifying treatment efficacy across any of the 23 conditions studied. However, the authors noted that the trials were not designed to assess variation in treatment efficacy by comorbidity.

These findings suggest that for modest levels of comorbidities, this assumption is reasonable.

Hanlon P, Butterly EW, Shah AS, Hannigan LJ, Lewsey J, Mair FS, et al. Treatment effect modification due to comorbidity: Individual participant data meta-analyses of 120 randomised controlled trials, PLoS Medicine (2023). DOI: 10.1371/journal.pmed.1004176

Synthetic species created without biochemistry operate according to Darwinian evolutionary principles

Imagine the possibility of life forms on other planets that don't resemble any on Earth. What might they look like, and why would they be so different?

This may be possible and the answer may be that they developed from a different type of chemistry.

Some researchers have studied how to produce synthetic living systems—without relying on biochemistry, or the chemistry that has enabled life on Earth. They have been have been trying to build a non-biochemical system, which unaided is capable of executing the essential properties common to all natural living systems. 

  One latest study, published last month in Cell Reports Physical Science, even finds such a system engaged in what Charles Darwin called "the struggle for life.

Researchers   created two synthetic models (or "species") and observed the ensuing competition between them. They figured out how to create non-biochemical but carbon-chemistry-based systems called protocells. These are made up of self-assembling polymer vesicles that emerge from a homogenous blend of smaller synthetic chemicals with no relation to living organisms. "These systems act like biochemical cells. They are born, metabolize what they need, grow, move, reproduce, and perhaps even evolve.

Now the researchers wanted to see whether these systems would operate according to the evolutionary principle of competitive exclusion. As we know from Darwin's work, this involves the struggle for survival—with the species with the greatest competitive advantage edging out the other when vying for resources.

They created two new species of protocells for this particular study—one with the advantage of light sensitivity, the other without. When the researchers watched how these systems behaved as they shared food in an illuminated environment, they saw that the light-sensitive "species" endured while the other did not. "It's the struggle for existence where the best-suited structure survived in its environment.

With these results, these researchers are  willing to go as far as to suggest that biochemicals are not essential to the struggle for life. This shows that non-biochemical carbon chemistry can lead to the extinction of the less 'fit' protocell species. 

Could there be chemistries beyond Earth capable of implementing the fundamental properties of life?

It's possible there are materials, which once on a planetary surface somewhere with appropriate conditions, could react chemically, self-organize, and perhaps do the things that this experiment shows.

Under the right circumstances, these materials may evolve from very simple chemistry into more complicated structures.

So these scientists think we should be very open about other forms of life elsewhere in the universe, and that they may not resemble life as we recognize it now.

Sai Krishna Katla et al, Competitive exclusion principle among synthetic non-biochemical protocells, Cell Reports Physical Science (2023). DOI: 10.1016/j.xcrp.2023.101359

A documented case of a crocodile virgin birth

A team of entomologists and reptile specialists from Virginia Polytechnic Institute and State University, the Chiricahua Desert Museum, the Illinois Natural History Survey, Reptilandia Reptile Lagoon and Parque Reptilandia has documented a case of a virgin crocodile laying viable eggs. In their paper published in the journal Biology Letters, the group describes their surprise at the discovery of a clutch of eggs laid by an American crocodile who had been kept alone in an enclosure at Parque Reptilandia park in Costa Rica for 16 years prior to laying the eggs.

Prior research has found instances of "virgin birth"—a type of asexual reproduction in a species that normally reproduces sexually—in snakes, lizards, sharks and birds, but never in Crocodilia, an order that includes gharials, caimans, alligators and crocodiles. So the handlers at Parque Reptilandia were surprised to see a clutch of eggs in an enclosure hosting a single American crocodile.

Alligators are well known in North America, but crocodiles live there, too, in parts of Florida. They also live in Central and South America. They normally mate to reproduce, like most other reptiles, and lay eggs that later hatch. But now, it appears that they can reproduce asexually if need be.

The clutch of 14 eggs was discovered back in 2016. After handlers noted their arrival, they notified local specialists. The eggs were collected and taken to a lab for study, where researchers found that half of them were viable. The viable eggs were placed in an incubator with the hope of producing hatchlings.

None of the eggs produced any, unfortunately, leading the researchers to crack them open after three months to see what was going on. All of the eggs had progressed toward hatching, but only one actually resembled a fetus. A genetic study of the most advanced specimen revealed that it was nearly identical to its mother.

The research team notes that it was not surprising that none of the eggs were hatchable; eggs laid in such fashion rarely are. Now that virgin births have been documented in both birds and Crocodilia, it raises the question of whether pterosaurs and/or dinosaurs were able to do so, as well.

Remains of an extinct world of organisms discovered

Newly discovered biomarker signatures point to a whole range of previously unknown organisms that dominated complex life on Earth about a billion years ago. They differed from complex eukaryotic life as we know it, such as animals, plants and algae in their cell structure and likely metabolism, which was adapted to a world that had far less oxygen in the atmosphere than today.

An international team of  researchers now reports on this breakthrough for the field of evolutionary geobiology in the journal Nature.

The previously unknown "protosteroids" were shown to be surprisingly abundant throughout Earth's Middle Ages. The primordial molecules were produced at an earlier stage of eukaryotic complexity—extending the current record of fossil steroids beyond 800 and up to 1,600 million years ago. Eukaryotes is the term for a kingdom of life including all animals, plants and algae and set apart from bacteria by having a complex cell structure that includes a nucleus, as well as a more complex molecular machinery.

This "stem" represents the common ancestral lineage that was a precursor to all still living branches of eukaryotes. Its representatives are long extinct, yet details of their nature may shed more light on the conditions surrounding the evolution of complex life.

Although more research is needed to evaluate what percentage of protosteroids may have had a rare bacterial source, the discovery of these new molecules not only reconciles the geological record of traditional fossils with that of fossil lipid molecules, but yields a rare and unprecedented glimpse of a lost world of ancient life.

The competitive demise of stem group eukaryotes, marked by the first appearance of modern fossil steroids some 800 Million years ago, may reflect one of the most incisive events in the evolution of increasingly complex life.

How an earthquake becomes a tsunami

The movement between continental and oceanic plates at the bottom of the sea, so-called megathrust earthquakes, generates the strongest tremors and the most dangerous tsunamis. How and when they occur, however, has been poorly understood so far, since the ocean floor is difficult to access for measurements.

Thanks to new technologies, an international research team was able to take measurements to the nearest centimeter for the first time in an underwater-earthquake zone off Alaska. The researchers reported on their findings in the specialist journal Science Advances.

The Chignik earthquake on July 28, 2021, occurred 32 km below the seafloor off the coast of Alaska and, with a magnitude of 8.2, was the seventh strongest earthquake in US history. It occurred because the oceanic Pacific Plate is sliding past the continental North American Plate, thereby causing an enormous thrust.

In the sparsely populated region, the damage caused by the quake was limited. In general, however, such megathrust earthquakes have enormous destructive potential in the so-called subduction zone, i.e. the zone where oceanic and continental tectonic plates meet. In particular, tsunami waves can be generated. These are not very high at their place of origin, but hours later and many 100 or 1000 kilometers away, they can hit the coasts as a catastrophic tsunami and endanger many lives.

Researchers examined the seafloor off Alaska shortly before and about 2.5 months after the Chignik quake, using a global navigation satellite system (GNSS), an acoustic positioning system, and a robotic ship.

In the project, a key role was played by autonomous vessels , called wave gliders, that operate on the water surface.

The modern technology allowed measurements of the movements in the subduction zones to the nearest centimeter and thus a precise picture of the complicated slip processes and faults. Particular attention was paid to the shallow portions of the slip zones, as these are critical to whether or not a tsunami will occur. The measurements were taken at a water depth of 1,000 to 2,000 meters.

Benjamin A. Brooks et al, Rapid shallow megathrust afterslip from the 2021 M8.2 Chignik, Alaska earthquake revealed by seafloor geodesy, Science Advances (2023). DOI: 10.1126/sciadv.adf9299

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'AI doctor' better at predicting patient outcomes, including death

Artificial intelligence has proven itself useful in reading medical imaging and even shown it can pass doctors' licensing exams.

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Food safety: Cleaning with plasma instead of chemicals

A new method for cleaning conveyor belts in food production can replace the widely used disinfection chemicals. Plasma-treated water is effective against microbial contamination at a shorter exposure time and degrades without environmentally hazardous traces. These results were recently published in the journal Innovative Food Science and Emerging Technologies.

Science was heard’: woman who was convicted of killing her children pardoned after inquiry

Vinuesa identified mutations in a gene called calmodulin 2 in Folbigg’s genome as well as in those of her two daughters, which could have explained the girls’ deaths. But that evidence was not enough to convince the commissioner of the first inquiry, who upheld Folbigg’s convictions. So in 2019, Vinuesa contacted the Australian Academy of Science, which gathered support to petition the governor of New South Wales to grant Folbigg a pardon, based on subsequent work by Overgaard and others that showed how the mutations impaired protein function.

At that stage, every other legal avenue had been exhausted. The governor ordered a new inquiry, and its commissioner, former state chief justice Thomas Bathurst, appointed the academy to act as a scientific adviser.

In that role, the academy recommended scientific expert witnesses and advised on the scope of expertise for each witness. The academy put forward some 30 researchers, around half of whom presented evidence at the inquiry. Other experts were also called by the prosecution and defence teams. The academy’s chief executive, Anna-Maria Arabia, says the inquiry heard “the most up-to-date science from the most qualified scientists, wherever they were in the world”. The expert witnesses were independent of both the prosecution and defence, says Arabia, and available for all parties to interrogate.

Peter Schwartz, a cardiologist at the Italian Auxological Institute in Milan, Italy, and a world leader in calmodulin mutations that cause sudden death, was one of the expert witnesses. He has advised on nearly 40 medico-legal cases, mostly in the United States, and says that having independent advice from the academy helped to ensure relevant experts presented world-leading evidence to the inquiry, instead of relying on one or two local experts. “I don’t recall ever having seen that in a trial of this kind,” he says, and “it goes to the credit of the Australian justice system.”

Overgaard says that he and other experts were given time to provide the necessary background so that lawyers thoroughly understood the science. On one occasion, he spent more than five hours explaining how mutations in the calmodulin protein could impair its function. The inquiry was also put on hold at one stage so that Overgaard and his team could update their evidence with results of further experiments they ran to address another expert’s questions, he says.

Part 2

The case demonstrates how the science and justice systems can work together, and that it should prompt law reforms to create a more “science-sensitive legal system”. She and others are calling for the establishment of a criminal case review commission, similar to that in the United Kingdom, which can revisit cases when there are advances in the science and new evidence comes to light.

But despite praise for the process, researchers caution that science doesn’t necessarily make a case black and white. “When the science is really nuanced, and really new and evolving as this was, you still may not get consensus.

https://www.nature.com/articles/d41586-023-01871-8?utm_source=Natur...

Part 3

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Taurine may be a key to longer and healthier life

A deficiency of taurine—a nutrient produced in the body and found in many foods—is a driver of aging in animals, according to a new study by researchers and involving dozens of aging researchers around the world.

The same study also found that taurine supplements can slow down the aging process in worms, mice, and monkeys and can even extend the healthy lifespans of middle-aged mice by up to 12%. The study was published June 8 in Science.

Over the past two decades, efforts to identify interventions that improve health in old age have intensified as people are living longer and scientists have learned that the aging process can be manipulated.

Many studies have found that various molecules carried through the bloodstream are associated with aging. Less certain is whether these molecules actively direct the aging process or are just passengers going along for the ride. If a molecule is a driver of aging, then restoring its youthful levels would delay aging and increase healthspan, the years we spend in good health.

Researchers realized that if taurine is regulating all these processes that decline with age, maybe taurine levels in the bloodstream affect overall health and lifespan.

Part 1

Researchers looked at levels of taurine in the bloodstream of mice, monkeys, and people and found that the taurine abundance decreases substantially with age. In people, taurine levels in 60-year-old individuals were only about one-third of those found in five-year-olds.

That's when they started to ask if taurine deficiency is a driver of the aging process, and they set up a large experiment with mice.

The researchers started with close to 250 14-month-old female and male mice (about 45 years old in people terms). Every day, the researcher fed half of them a bolus of taurine or a control solution. At the end of the experiment, they found that taurine increased average lifespan by 12% in female mice and 10% in males. For the mice, that meant three to four extra months, equivalent to about seven or eight human years.

Experts measured various health parameters in mice and found that at age two (60 in human years), animals supplemented with taurine for one year were healthier in almost every way than their untreated counterparts.

The researchers found that taurine suppressed age-associated weight gain in female mice (even in "menopausal" mice), increased energy expenditure, increased bone mass, improved muscle endurance and strength, reduced depression-like and anxious behaviors, reduced insulin resistance, and promoted a younger-looking immune system, among other benefits. Not only did researchers find that the animals lived longer, they also found that they're living healthier lives.

At a cellular level, taurine improved many functions that usually decline with age: The supplement decreased the number of "zombie cells" (old cells that should die but instead linger and release harmful substances), increased survival after telomerase deficiency, increased the number of stem cells present in some tissues (which can help tissues heal after injury), improved the performance of mitochondria, reduced DNA damage, and improved the cells' ability to sense nutrients. Similar health effects of taurine supplements were seen in middle-aged rhesus monkeys, which were given daily taurine supplements for six months. Taurine prevented weight gain, reduced fasting blood glucose and markers of liver damage, increased bone density in the spine and legs, and improved the health of their immune systems.

The researchers do not know yet if taurine supplements will improve health or increase longevity in humans, but two experiments they conducted suggest taurine has potential.

Parminder Singh et al, Taurine deficiency as a driver of aging, Science (2023). DOI: 10.1126/science.abn9257. www.science.org/doi/10.1126/science.abn9257

Part 2

Long COVID can impact fatigue and quality of life worse than some cancers, finds new study

Fatigue is the symptom that most significantly impacts the daily lives of long COVID patients, and can affect quality of life more than some cancers, finds a new study by researchers.

The research, published in BMJ Open , examines the impact of long COVID on the lives of over 3,750 patients who were referred to a long COVID clinic .

Patients were asked to complete questionnaires on the app about how long COVID was affecting them—considering the impact of long COVID on their day-to-day activities, levels of fatigue, depression, anxiety, breathlessness, brain fog, and their quality of life.

The researchers found that many long COVID patients were seriously ill and on average had fatigue scores worse or similar to people with cancer-related anemia or severe kidney disease. Their health-related quality of life scores were also lower than those of people with advanced metastatic cancers, like stage IV lung cancer.

Overall, the team found that the impact of long COVID on the daily activities of patients was worse than that of stroke patients and was comparable to that of patients with Parkinson's disease.

These results have found that long COVID can have a devastating effect on the lives of patients—with fatigue having the biggest impact on everything from social activities to work, chores and maintaining close relationships."

Not only does long COVID negatively impact the lives of patients on an individual level, the researchers also think that it could have a significant economic and social impact on any country.

Henry Goodfellow et al, The impact of fatigue as the primary determinant of functional limitations amongst patients with Post-COVID syndrome: a cross-sectional observational study, BMJ Open (2023). DOI: 10.1136/bmjopen-2022-069217

US lawyer sorry after ChatGPT creates 'bogus' cases

What happened when a US lawyer used ChatGPT to prepare a court filing? The artificial intelligence program invented fake cases and rulings, leaving the attorney rather red-faced.

New York-based lawyer Steven Schwartz apologized to a judge this week for submitting a brief full of falsehoods generated by the OpenAI chatbot.

"I simply had no idea that ChatGPT was capable of fabricating entire case citations or judicial opinions, especially in a manner that appeared authentic," Schwartz wrote in a court filing.

The blunder occurred in a civil case being heard by Manhattan federal court involving a man who is suing the Colombian airline Avianca.

Roberto Mata claims he was injured when a metal serving plate hit his leg during a flight in August 2019 from El Salvador to New York.

After the airline's lawyers asked the court to dismiss the case, Schwartz filed a response that claimed to cite more than half a dozen decisions to support why the litigation should proceed.

They included Petersen v. Iran Air, Varghese v. China Southern Airlines and Shaboon v. Egyptair. The Varghese case even included dated internal citations and quotes.

There was one major problem, however: neither Avianca's attorneys nor the presiding judge, P. Kevin Castel could find the cases.

Schwartz was forced to admit that ChatGPT had made up everything.

"The court is presented with an unprecedented circumstance," judge Castel wrote last month.

"Six of the submitted cases appear to be bogus judicial decisions with bogus quotes and bogus internal citations," he added.

The judge ordered Schwartz and his law partner to appear before him to face possible sanctions.

Scientists develop artificial molecules that behave like real ones

Scientists  have developed synthetic molecules that resemble real organic molecules. A collaboration of researchers can now simulate the behaviour of real molecules by using artificial molecules. In this way, they can tweak properties of molecules in ways that are normally difficult or unrealistic, and they can understand much better how molecules change.

Researchers developed a system in which they can trap electrons. Electrons surround a molecule like a cloud, and they used those trapped electrons to build an artificial molecule. The results the team found were astonishing.  "The resemblance between what they built and real molecules was uncanny."

Using this simulator, the researchers created an artificial version of one of the basic organic molecules in chemistry, benzene. Benzene is the first component for a number of chemicals, like styrene, which is used to make polystyrene. By making benzene, they simulated a textbook organic molecule, and built a molecule that is made up of elements that are not organic. In addition, the molecules are 10 times bigger than their real counterparts, which makes them easier to work with.

E. Sierda et al, Quantum simulator to emulate lower-dimensional molecular structure, Science (2023). DOI: 10.1126/science.adf2685. www.science.org/doi/10.1126/science.adf2685

Researchers discover a new way to develop drugs without side effects

Have you ever wondered how drugs reach their targets and achieve their function within our bodies? If a drug molecule or a ligand is a message, an inbox is typically a receptor in the cell membrane. One such receptor involved in relaying molecular signals is a G protein-coupled receptor (GPCR). About one-third of existing drugs work by controlling the activation of this protein. Researchers now reveal a new way of activating GPCR by triggering shape changes in the intracellular region of the receptor. This new process can help researchers design drugs with fewer or no side effects.

If the cell membrane is like an Oreo cookie sandwich, GPCR is like a snake with seven segments traversing in and out of the cookie sandwich surface. The extracellular loops are the inbox for messages. When a message molecule binds to the extracellular side of the receptor, it triggers a shape change activating G proteins and the ß-arrestin protein attached to the intracellular side of the receptor. Like a molecular relay, the information passes downstream and affects various bodily processes. That is how we see, smell, and taste, which are sensations of light, smell, and taste messages.

Adverse side effects ensue if drugs acting on GPCRs activate multiple signaling pathways rather than a specific target pathway. That is why drug development focuses on activating specific molecular signal pathways within cells. Activating the GPCR from inside the cell rather than outside the cell could be one way to achieve specificity. But until now, there was no evidence of direct activation of only the intracellular side of GPCRs without the initiations from the extracellular side.

A team of researchers discovered a new receptor activation mode of a bone metabolism-related GPCR called human parathyroid hormone type 1 receptor (PTH1R) without signal transduction from the extracellular side.

Kazuhiro Kobayashi et al, Class B1 GPCR activation by an intracellular agonist, Nature (2023). DOI: 10.1038/s41586-023-06169-3

Older folks found to foist more moist particles into the air

Research led by the Department of Aerospace Engineering, Institute of Fluid Mechanics and Aerodynamics, Universität der Bundeswehr München, Germany, has found unexpectedly high aerosolized respiratory particle emissions from people over 60 years old.

In their paper, "Lung aerosol particle emission increases with age at rest and during exercise," published in PNAS, the researchers detail their findings after testing 80 individuals with a recently improved method of measuring respiratory aerosol particle emission.

Airborne respiratory diseases are transmitted via viruses in respiratory aerosol particles. When a person breathes out, a high-speed stream of air rushes over the surface of the wet lining of the respiratory tract, and some of this moisture is aerosolized and carried out with the exhale. Particles within the lining hitch a ride on the exiting moisture containing a mix of salts, proteins, mucus, and potential pathogens of bacteria and viruses.

Typically the emission of aerosol particles can increase by more than 100-fold from rest to peak exercise, and with the increase, the risk of infection can rise by more than 10-fold. While testing their improved measuring method, the researchers found another significant parameter affecting the amount of particle spread—age.

Subjects aged 60 to 76 years old emitted over twice as many aerosol particles at rest and during exercise and five times as much aerosol volume. This suggests that aerosol particle emission increases when the respiratory system ages.

Part 1

At rest, the expired air of older subjects (60-76) contained an average respiratory aerosol particle concentration of 310 particles/L compared to 105 particles/L in younger subjects. The study found differences between elderly men and women, with elderly men emitting 210 particles/L compared to elderly women at 500 particles/L. While the elderly women had more than twice the particle load per liter of air, the elderly men ventilated 57% more volume than elderly women making the overall difference insignificant.

The difference was more significant during exercise as the young group averaged 620 particles/L while the elderly group reached an average of 2,090 particles/L.

While age significantly affected aerosol particle emission, sex and body mass index differences were not significant. The study highlights that one size may not fit all when planning mitigation measures, especially for indoor fitness facilities or elder care facilities during heightened infection waves or future pandemics.

What Dreams May Mean
Dreams can be bizarre and disturbing, and even sometimes frightening. Do some betray a pathology? Dreams alone are not enough to diagnose a mental illness. But some characteristics of a dream may hint at disorders: for example, the frequency of nightmares is generally higher in people with a mental disorder, whether depression, anxiety or post-traumatic stress disorder (they’re particularly indicative of a person’s risk for suicide).

Why this is cool: Dreams may serve to integrate memories and lessen negative emotions around difficult life experiences; in fact, people tend to wake up happier than when they went to sleep (what I’m hearing: more naps, because SCIENCE). Those systems can get derailed in people with depression or PTSD.

What the experts say: Dreams can be useful in diagnosing some brain disorders, like differentiating between Alzheimer's and Lewy body dementia. Both involve cognitive loss, but the latter is accompanied by REM sleep behavior disorder, where the dreamer tries to physically act out what’s happening in their dream.

https://www.scientificamerican.com/article/how-dreams-reveal-brain-...

Millions wasted on reformatting papers

Scientists are spending millions of dollars’ worth of time reformatting rejected papers for submission to alternative journals. An analysis shows that, in 2021, the global price tag on all of tha... — just for biomedical journals. If current journal practices don’t change, the authors estimate that reformatting could cost about $2.5 billion between 2022 and 2030. Suggested remedies include universal journal guidelines, free-format submissions or a ‘golden middle’ solution that allows researchers to submit manuscripts that abide by minimal structural requirements, such as total word count. “The current system is not sustainable,” says study co-author Tibor Varga.

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Why didn't the Big Bang collapse in a giant black hole?

Despite the enormous densities, the early universe didn't collapse into a black hole because, simply put, there was nothing to collapse into.

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Limiting global warming to 2C is not enough—why the world must keep...

The Paris Climate agreement represented a historic step towards a safer future for humanity on Earth when it was adopted in 2015. The agreement strove to keep global heating below 2℃ above pre-industrial levels with the aim of limiting the increase to 1.5℃ if possible. It was signed by 196 parties around the world, representing the overwhelming majority of humanity.

 Amorphous Ice

Researchers discover that COVID-19 can cause brain cells to fuse

Researchers have discovered viruses such as SARS-CoV-2 can cause brain cells to fuse, initiating malfunctions that lead to chronic neurological symptoms. They have explored how viruses alter the function of the nervous system. Their research is published in Science Advances.

SARS-CoV-2, the virus that causes COVID-19, has been detected in the brains of people with "long COVID" months after their initial infection.

It's discovered now that COVID-19 causes neurons to undergo a cell fusion process, which has not been seen before.

Once fusion takes place, each switch either turns on both the kitchen and bathroom lights at the same time, or neither of them.  It's bad news for the two independent circuits.

The discovery offers a potential explanation for persistent neurological effects after a viral infection. In the current understanding of what happens when a virus enters the brain, there are two outcomes—either cell death or inflammation. But this new work has shown a third possible outcome, which is neuronal fusion.

Numerous viruses cause cell fusion in other tissues, but also infect the nervous system and could be causing the same problem there.

These viruses include HIV, rabies, Japanese encephalitis, measles, herpes simplex virus and Zika virus. This  research reveals a new mechanism for the neurological events that happen during a viral infection. This is potentially a major cause of neurological diseases and clinical symptoms that is still unexplored.

Ramón Martínez-Mármol et al, SARS-CoV-2 infection and viral fusogens cause neuronal and glial fusion that compromises neuronal activity., Science Advances (2023). DOI: 10.1126/sciadv.adg2248. www.science.org/doi/10.1126/sciadv.adg2248

Why you can’t eat or drink before a general anaesthetic

When you have a general anaesthetic, you will usually be asked not to have anything to eat or drink for a period of time before. Although you might get annoyed, this is for your won safety. 

When the general anaesthetic is used, your body’s reflexes are temporarily stopped. If your stomach has any food and drink in it, there’s a risk of vomiting or bringing up food into your throat. If this happens, the food could get into your lungs and affect your breathing, as well as causing damage. Inhaling vomited stomach contents into your lungs is called ‘aspiration’, and it can lead to a dangerous infection.

The amount of time you have to go without food or drink before you have your operation will depend on the type of operation you’re having. However, it is usually at least six hours for food, and two hours for fluids. You’ll be told how long you must not eat or drink before your operation.

Unfortunately, even chewing gum – including nicotine gum – should be avoided during this fasting period, and soups and sweets should also not be consumed. You may also be advised to avoid certain types of fluids, such as milk, or tea and coffee with milk added to them. Clear fluids, such as water, are usually allowed until two hours before.

While it might feel annoying to avoid food, you must follow the guidelines. If you eat or drink before your surgery, your operation can be postponed or even cancelled because of the risks involved.

Octopuses Can Rewire Their 'Brains' by Editing Their Own RNA on The Fly

Octopuses have found an incredible way to protect the more delicate features of their nervous system against radically changing temperatures.

When conditions fluctuate, they can rapidly recode key proteins in their nerve cells, ensuring critical neurological activities remain functional when temperatures drop dramatically.

How do they do it? By deploying a rare superpower – editing their RNA on the fly, an ability found in some species of octopuses, squids and cuttlefish.

It's an unusual strategy, but it appears to be an effective one, and scientists think that it may be widely adopted throughout the world of cephalopods.

We generally think that our genetic information is fixed, but the environment can influence how you encode proteins, and in cephalopods this happens on a massive scale.

RNA recoding gives organisms the option to express a diverse quiver of proteins when and where they choose. In cephalopods, most of the recoding is for proteins that are really important for nervous system function, so the natural question is, are they using this to acclimate to changes in their physical environment?"

Part 1

Our own genetic instructions for survival can change, but it tends to happen slowly, with generational tweaking of DNA. Variations in the genetic code determine the ultimate shape and function of individual proteins that build our bodies, including the systems and structural supports inside our brain.

DNA doesn't make the proteins directly, though. Those chemically encoded instructions remain in the nucleus of your cells, issuing templates through an intermediate molecule called messenger RNA (or mRNA), which travels from the nucleus into the surrounding goo to feed into tiny protein-building machines.

In most organisms, this is pretty straightforward; once the template is issued, no more change occurs to the RNA. In cephalopods, however, things are a little different.

In 2015, scientists found that squids, cuttlefish, and octopuses can tweak the RNA after it has left the nucleus, editing on the fly, allowing for a rapid physiological response to … what? Some scientists thought it might be the reason cephalopods are so strangely, fascinatingly smart, but the reason for it has eluded us, and baffled scientists.

Adapting to temporary environmental changes seemed like a plausible explanation. Marine organisms are subjected to a wide range of temperatures, and octopuses lack the ability to actively thermoregulate. RNA editing would offer the ability to change, and change again as conditions dictate, without the long-term implementation and relative permanence of DNA editing.

--

These findings suggest that at least one function of cephalopod RNA editing is a rapid response to conditions that might be dangerous to the animals otherwise. There are also other environmental variables that could invoke a response. These include low oxygen, pollution, and changing social conditions.

The researchers suspect that RNA editing is a fairly widespread strategy among octopuses and squids to stay alive as their environment changes, and plan to investigate how it is used in greater detail.

https://www.cell.com/cell/fulltext/S0092-8674(23)00523-8

Part 2

White Dwarf Star Enters Its Crystallization Era, Turning Into A 'Cosmic Diamond'

To us, stars may resemble cut jewels, glittering coldly against the velvet darkness of the night sky. And for some of them, that may actually be sort of true.

As a certain type of dead star cools, it gradually hardens and crystallizes. Astronomers have found one doing just that in our cosmic backyard, a white dwarf composed primarily of carbon and metallic oxygen just 104 light-years away, whose temperature-mass profile suggests that the center of the star is transforming into a dense, hard, 'cosmic diamond' made up of crystallized carbon and oxygen.

White dwarf stars are dim, but they still shine with residual heat. Over time, they cool, and are expected to evolve into something called a black dwarf stars when they lose all their heat and become a cold lump of crystallized carbon.

Calculations suggest that this process takes a very long time, about a quadrillion years (that's a million billion years); since the Universe is only about 13.8 billion years old, we don't expect to find one anytime soon.

What we can do is identify the signs of crystallization starting in the cores of the white dwarfs we see around us.

During crystallization, the carbon and oxygen atoms inside the white dwarf stop moving about freely and form bonds, arranging themselves into a crystal lattice. Energy is released during this process, which dissipates in the form of heat.

This produces a sort of plateau or slowing in the cooling of white dwarf stars, which can be observed in the color and brightness of the star, making it appear younger than it actually is.

https://arxiv.org/abs/2306.03140

The discovery is detailed in a paper accepted into the Monthly Notices of the Royal Astronomical Society and available on preprint website arXiv.

Gout strongly associated with reduced gray matter and increased neurodegenerative disease

Researchers recently conducted a study  a study into the relationship between gout and neurodegenerative disease. In the paper, "Association of gout with brain reserve and vulnerability to neurodegenerative disease," published in Nature Communications, they find remarkable links between the common arthritis joint ailment and neurodegenerative disease.

The results from a combination of observational and genetic approaches indicate that gout patients have smaller global and regional brain volumes and markers of higher brain iron. Participants with gout also had higher incidences of all-cause dementia, Parkinson's disease, and probable essential tremor, particularly in the first three years after diagnosis.

The observations suggest that lower neuroanatomic resources among gout patients may explain their higher vulnerability to multiple neurodegenerative diseases. Genetic associations mostly mirrored observational ones. Both genetically predicted gout and serum urate were significantly associated with regional gray matter volumes.

Gout is the most common inflammatory arthritis affecting ~1% to 4% of the population. Insufficient kidney filtering or overproduction of uric acid can cause a build-up and the formation of tiny sharp crystals in and around joint tissues. The clinical syndrome of gout is characterized by acute joint pain and swelling resulting from urate crystals. The brain has not been previously thought to be affected.

These results support a strong correlation between gout and neurodegenerative disease. The authors suggest that patients with gout should be monitored for cognitive and motor symptoms of neurodegenerative disease, given their increased risk, especially in the early period after diagnosis.

What microplastics might be doing to our intestines

Plastics are among the most ubiquitous manmade materials—we wear them, build with them, play with them, ship goods in them, and then we throw them into the waste stream. Ultimately, they can break down into tiny particles that get into our food supply, and we end up eating them.

In a study published in Nanomedicine: Nanotechnology, Biology and Medicine, researchers  have found potential inflammatory effects of plastic particles using human intestinal organoids—small bundles of tissue made from a mix of human cells obtained from biopsies that mimic the complexity of an actual intestinal environment.

Notably, the researchers found that higher concentrations of plastic particles triggered the secretion of inflammatory molecules linked to human inflammatory bowel disease (IBD).

Earlier clinical studies have found plastics accumulated in different tissues of living organisms, including the digestive tract, blood, liver, pancreas, heart, and even the brain. The most likely first point of entry is through the intestine. Studies on rats and other animals have found that while microplastics and nanoplastics may accumulate in the intestine and other tissues, there are conflicting results on toxic effects or inflammation, which may depend on particle size, length of exposure, and pre-existing conditions. 

We know that particulate plastic is everywhere in the environment, and it has been found in human intestines and other tissues, like blood, and even in the brain and placenta.

Different cells were found to absorb different sizes of particles. Epithelial cells that normally line the inside of the intestine would absorb the tiniest nanoparticles, while microfold or "M" cells would absorb and transport larger microparticles into the intestinal tissue. The researchers also found that damage caused by plastic particles to the model intestinal lining occurred only when M cells were present and at higher concentrations of particles. Damage to the cell layer may imply the potential for generating intestinal lesions.

Part 1

Notably, the researchers also observed that higher concentrations of plastic nanoparticles triggered the organoid layer to release inflammatory cytokines—molecules that are a part of the normal immune response, but may relate to diseases including Inflammatory Bowel Disease (IBD) when they are set off balance. This effect was also dependent on the presence of M cells, which suggests those cells play a critical role in mediating potential damage to the intestine by plastic microparticles. More research will have to be done to clarify the impact of concentration, chemistry and surface features of plastic  particles on M cell functions.

 Ying Chen et al, Biological effects of polystyrene micro- and nano-plastics on human intestinal organoid-derived epithelial tissue models without and with M cells, Nanomedicine: Nanotechnology, Biology and Medicine (2023). DOI: 10.1016/j.nano.2023.102680

Part 2

For a billion years of Earth's history our days were only 19 hours long, finds new study

Although we take the 24-hour day for granted, in Earth's deep past, days were even shorter.

Day length was shorter because the moon was closer. Over time, the moon has stolen Earth's rotational energy to boost it into a higher orbit farther from Earth.

Most models of Earth's rotation predict that day length was consistently shorter and shorter going back in time.

How do researchers measure ancient day length? In past decades, geologists used records from special sedimentary rocks preserving very fine-scale layering in tidal mud flats. Count the number of sedimentary layers per month caused by tidal fluctuations and you know the number of hours in an ancient day.

But such tidal records are rare, and those preserved are often disputed. Fortunately, there's another means of estimating day length.

Cyclostratigraphy is a geologic method that uses rhythmic sedimentary layering to detect astronomical "Milankovitch" cycles that reflect how changes in Earth's orbit and rotation affect climate. Two Milankovitch cycles, precession and obliquity, are related to the wobble and tilt of Earth's rotation axis in space. The faster rotation of early Earth can therefore be detected in shorter precession and obliquity cycles in the past.

Researchers took advantage of a recent proliferation of Milankovitch records, with over half of the data for ancient times generated in the past seven years.

Part 1

One unproven theory is that day length might have stalled at a constant value in Earth's distant past. In addition to tides in the ocean related to the pull of the moon, Earth also has solar tides related to the atmosphere heating up during daytime.

Solar atmospheric tides are not as strong as lunar oceanic tides, but this would not always have been the case. When Earth was rotating faster in the past, the tug of the moon would have been much weaker. Unlike the pull of the moon, the sun's tide instead pushes Earth. So while the moon slows Earth's rotation down, the sun speeds it up.

Because of this, if in the past these two opposite forces were to have become been equal to each other, such a tidal resonance would have caused Earth's day length to stop changing and to have remained constant for some time.

And that's exactly what the new data compilation showed.

Earth's day length appears to have stopped its long-term increase and flatlined at about 19 hours roughly between two to one billion years ago.

The timing of the stalling intriguingly lies between the two largest rises in oxygen.

The new study thus supports the idea that Earth's rise to modern oxygen levels had to wait for longer days for photosynthetic bacteria to generate more oxygen each day.

Mitchell, R.N. et al, Mid-Proterozoic day length stalled by tidal resonance, Nature Geoscience (2023). DOI: 10.1038/s41561-023-01202-6. www.nature.com/articles/s41561-023-01202-6

part 2

New study reveals how blood triggers brain disease

 In patients with neurological diseases like Alzheimer's disease and multiple sclerosis, immune cells in the brain known as microglia that normally fulfill beneficial functions become harmful to neurons, leading to cognitive dysfunction and motor impairment. These harmful immune cells may also contribute to age-related cognitive decline in people without dementia.

For some time, scientists have been trying to better understand the triggers responsible for turning good microglia bad, and their exact contribution during disease. If they could identify what makes microglia toxic, they could find new ways to treat neurological diseases.

Now, researchers  showed that exposure to blood leaking into the brain turns on harmful genes in microglia, transforming them into toxic cells that can destroy neurons.

The scientists discovered that a blood protein called fibrin—which normally aids blood clotting—is responsible for turning on the detrimental genes in microglia, both in Alzheimer's disease and multiple sclerosis. The findings, published in the journal Nature Immunology, suggest that counteracting the blood toxicity caused by fibrin can protect the brain from harmful inflammation and loss of neurons in neurological diseases.

Individuals with neurological diseases like Alzheimer's disease and multiple sclerosis have abnormalities within the vast network of blood vessels in their brain, which allow blood proteins to seep into brain areas responsible for cognitive and motor functions. Blood leaks in the brain occur early and correlate with worse prognosis in many of these diseases.

In the new study, the researchers found that different blood proteins activate distinct molecular processes in microglia. What's more, they identified that fibrin is responsible for driving unique gene and protein activities that make microglia toxic to neurons. The other blood proteins tested were not mainly responsible for these toxic effects.

https://www.nature.com/articles/s41590-023-01522-0

Using Nanoparticles to Combat Antibiotic Resistance Bacteria

People who preserve 'immune resilience' live longer and resist infections, study finds

Researchers have revealed that the capacity to resist or recover from infections and other sources of inflammatory stress—called "immune resilience"—differs widely among individuals. The researchers developed a unique set of metrics to quantify the level of immune resilience. This will aid in decisions for health care and help researchers understand differences in life span and health outcomes in persons of similar ages. 

Although age plays an important role in the body's response to infectious and other inflammatory stressors, some persons preserve and/or restore optimal immune resilience regardless of age.

Immune resilience is the capacity to maintain good immune function, called immunocompetence, and minimize inflammation while experiencing inflammatory stressors. 

Researchers found that during aging and when experiencing inflammatory stress, some persons resist degradation of immune resilience.

individuals with optimal levels of immune resilience were more likely to:

• Live longer.
• Resist HIV and influenza infections.
• Resist AIDS.
• Resist recurrence of skin cancer after kidney transplant.
• Survive COVID-19 infection.
• Survive sepsis.

Part 1

One consistent finding throughout the populations studied was that age was not the single determinant factor in a person's response to inflammatory stress. Some younger persons with poor immune resilience had the same signatures and immune health grades commonly seen in older persons. This finding suggests that the ability to restore and maintain immunocompetence at younger ages may be linked to life span. Another factor noted across the populations and species was that higher levels of optimal immune resilience were observed more often in females than males.

These assessments have utility for understanding who might be at greater risk for developing diseases that affect the immune system, how individuals are responding to treatment, and whether, as well as to what extent, they will recover.

Sunil Ahuja, Immune resilience despite inflammatory stress promotes longevity and favorable health outcomes including resistance to infection, Nature Communications (2023). DOI: 10.1038/s41467-023-38238-6. www.nature.com/articles/s41467-023-38238-6

Part 2

 How microplastics stick around in human airways

Research shows humans might inhale about 16.2 bits of microplastic every hour, which is equivalent to a credit card over an entire week. And these microplastics—tiny debris in the environment generated from the degradation of plastic products—usually contain toxic pollutants and chemicals.

Inhaled microplastics can pose serious health risks, so understanding how they travel in the respiratory system is essential for prevention and treatment of respiratory diseases.

Researchers  explored the movement of microplastics with different shapes (spherical, tetrahedral, and cylindrical) and sizes (1.6, 2.56, and 5.56 microns) and under slow and fast breathing conditions.

Microplastics tended to collect in hot spots in the nasal cavity and oropharynx, or back of the throat.

The complicated and highly asymmetric anatomical shape of the airway and complex flow behavior in the nasal cavity and oropharynx causes the microplastics to deviate from the flow pathline and deposit in those areas.

The flow speed, particle inertia, and asymmetric anatomy influence the overall deposition and increase the deposition concentration in nasal cavities and the oropharynx area.

Breathing conditions and microplastic size influenced the overall microplastic deposition rate in airways. An increased flow rate led to less deposition, and the largest (5.56 micron) microplastics were deposited in the airways more often than their smaller counterparts.

This study emphasizes the need for greater awareness of the presence and potential health impacts of microplastics in the air we breathe.

How microplastics are transported and deposited in realistic upper airways, Physics of Fluids (2023). DOI: 10.1063/5.0150703

How cells kill themselves

Researchers  artificially re-creates cell 'skeletons' using strands of DNA

Seeing Dead Flies Makes Other Flies Die Faster

There might be a weird benefit to leaving dead flies where they fall .

Research has shown that when fruit flies of the species Drosophila melanogaster are exposed to the carcasses of their dead friends, their lifespan shrinks in a significant and measurable way.

They start acting withdrawn, lose body fat, and their aging accelerates to the point that they die sooner than fruit flies that don't see their dead buddies just lying where they fall like some macabre fruit fly graveyard.

And now scientists have a better idea about why this happens. Two neuron types receptive to the neurotransmitter serotonin become activated when fruit flies perceive dead comrades, and this increased activity accelerates the flies' aging process.

Scientists have seen similar effects in other animals: necrophoresis, or the removal of dead conspecifics, in eusocial insects; vocalization and corpse inspection in elephants; or an increase in levels of regulatory hormones called glucocorticoids in nonhuman primates.

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

Right-handed building blocks of life

Scientific research may have solved the puzzle of how life became molecularly right-handed. In the paper, "Origin of biological homochirality by crystallization of an RNA precursor on a magnetic surface," published in Science Advances, the researchers explain how it all might have started with the right kind of rocks.

Molecules can be left-handed, right-handed or both. RNA and the sugars that makeup DNA are right-handed molecules. Nobody knows why or if there is a reason beyond chance that life started right-handed.

As an analogy, human hands can be left or right, and they are mirror images of each other, which means that they cannot be superimposed without one facing the wrong way. Molecules can have similar structural symmetry.

In much the same way that right-handed people have difficulty with left-handed scissors, or left-handed guitar players need to reverse strings and play the instrument the other way round, molecules do not interact the same way when they are left or right-handed. Once started, it makes sense that the building blocks of life should continue with the same handedness.

One intriguing idea is that cosmic rays with left-handed spin destroyed left-handed DNA precursors just as life started on Earth.

Ribo-amino oxazoline (RAO) is a crucial RNA precursor for two of RNA's nucleotides, cytosine and uracil. RAO also happens to form a crystalline structure that can be either right-handed or left-handed that, once the crystal starts forming, right or left, only binds with other molecules of the same handedness.

By placing RAO on magnetite (Fe₃O₄) surfaces, researchers could achieve 100% handedness of RAO crystallization, either left or right, depending on the spin-exchange interaction and degree of spin alignment (magnetization) at the active surface.

Earth's most abundant natural magnetic mineral, magnetite, would have had plenty of interaction opportunities with RAO in primordial times. However, the researchers say the effect is not likely to occur in particle solution contact like mud but rather on sedimentary rock surfaces.

Even with the current findings possibly unlocking two of the four RNA nucleotide components, two more are still missing. So far, The origin story finds that common, naturally occurring components at room temperatures can start the process. If the next two are found to have similar requirements, it would indicate that life on any Earth-like planet in the universe could have started just as easily.

S. Furkan Ozturk et al, Origin of biological homochirality by crystallization of an RNA precursor on a magnetic surface, Science Advances (2023). DOI: 10.1126/sciadv.adg8274

S. Furkan Ozturk et al, Chirality-Induced Magnetization of Magnetite by an RNA Precursor, arXiv (2023). DOI: 10.48550/arxiv.2304.09095

New research shows illusions are in the eye, not the mind's neurons

Numerous visual illusions are caused by limits in the way our eyes and visual neurons work—rather than more complex psychological processes, new research shows.

Numerous visual illusions are caused by limits in the way our eyes and visual neurons work—rather than more complex psychological processes, new research shows.

The new study suggests simple limits to neural responses—not deeper psychological processes—explain these illusions.

Our eyes send messages to the brain by making neurons fire faster or slower. However, there's a limit to how quickly they can fire, and previous research hasn't considered how the limit might affect the ways we see color.

The model combines this "limited bandwidth" with information on how humans perceive patterns at different scales, together with an assumption that our vision performs best when we are looking at natural scenes.

The model was developed by researchers from the Universities of Exeter and Sussex to predict how animals see color, but it was also found to correctly predict many visual illusions seen by humans.

Part 1

Modern high dynamic range televisions create bright white regions that are over 10,000 times brighter than their darkest black, approaching the contrast levels of natural scenes.

How our eyes and brains can handle this contrast is a puzzle because tests show that the highest contrasts we humans can see at a single spatial scale is around 200:1.

Even more confusingly, the neurons connecting our eyes to our brains can only handle contrasts of about 10:1.

This new  model shows how neurons with such limited contrast bandwidth can combine their signals to allow us to see these enormous contrasts, but the information is 'compressed'—resulting in visual illusions.

The model shows how our neurons are precisely evolved to use of every bit of capacity.

"For example, some neurons are sensitive to very tiny differences in gray levels at medium-sized scales, but are easily overwhelmed by high contrasts.

"Meanwhile, neurons coding for contrasts at larger or smaller scales are much less sensitive, but can work over a much wider range of contrasts, giving deep black-and-white differences.

"Ultimately this shows how a system with a severely limited neural bandwidth and sensitivity can perceive contrasts larger than 10,000:1."

Endometriosis could be caused by bacteria

Endometriosis could be caused by Fusobacterium. The severely painful condition, in which tissue similar to the uterus lining grows outside the uterus, affects up to 10% of women. In a study of 155 women, the bacterium was found in around 64% of those with endometriosis a.... Experiments with Fusobacterium-infected mice showed that antibiotics could reduce the size and frequency of the lesions that are associated with the disease. A clinical trial is now under way to find out whether antibiotics could relieve some endometriosis symptoms.

https://www.science.org/doi/10.1126/scitranslmed.add1531

https://www.nature.com/articles/d41586-023-01956-4?utm_source=Natur...

Study finds that the human brain reactivates mental representations of past events during new experiences

Neuroscience studies have showed that as mice and other rodents navigate a maze, their brain often "replays" relevant past events. This mental replaying of events, such as the route taken until reaching their current position, could help rodents create a mental map of the spatial environment, and understand their position in it.

Researchers  recently explored the possibility that the human brain also replays past events to make sense of evolving, non-spatial experiences. Their findings, published in Nature Neuroscience, confirms this hypothesis and suggests that the process through which the human brain reactivates these events might be far more complex than that observed in rodents.

Researchers tried to devise an experiment that might elicit the replay of past events as observed in rodents, but during non-spatial daily experiences. Ultimately, they decided to ask their participants to watch a movie or listen to audio recordings of a narrated story while recording their brain activity using a functional magnetic resonance imaging (fMRI) scanner.

Movies and stories simulate real world experiences, as they are composed of events that should be linked together to understand the overall narrative.

Interestingly, researchers  found that as participants were engaged in the narrative of a movie or story, representations of past events, which were needed to make sense of each present scene, were reactivated in their brain. Unlike in rodents, these reactivations appeared while the participants were watching the movie or listening to the story, rather than during periods of rest from the task.

They found that the same brain regions that replay spatial information in the rodent brain also replay narrative events in the human brain. In other words, replay, previously thought to mainly support spatial navigation, could also underlie the human ability to make sense of narratives.  

Overall, the recent work by this team of researchers suggests that while humans are trying to make sense of their present experiences, their brain may continuously reactivate relevant past events. 

Avital Hahamy et al, The human brain reactivates context-specific past information at event boundaries of naturalistic experiences, Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01331-6

Scientists think disorienting the malaria parasite may prevent it from causing harm

With almost 250 million cases a year, 621,000 of them fatal, malaria remains a major public health problem, particularly in sub-Saharan Africa. Malaria is a parasitic disease transmitted by mosquitoes and caused by a microbe of the genus Plasmodium. On its journey from mosquito to human, Plasmodium must adapt to the specificities of the many organs and cells it parasitizes. Microbes do not have sensory organs; instead, they have sensors made of proteins to detect molecules specific to the environments they colonize. While most living organisms share the same types of sensors, Plasmodium is an exception.

Biologists have identified a new type of sensor that enables Plasmodium to know precisely where it is and what to do. This work, published in the journal Science Advances, opens up the possibility of scrambling the signals perceived by this sensor to disorient the parasite and thus prevent its replication and transmission.

When a human is bitten by a Plasmodium-infected mosquito, the parasite enters the bloodstream and travels to the liver, where it thrives for around 10 days without causing any symptoms. After this period, Plasmodium re-enters the bloodstream, where it parasitizes red blood cells. Once inside the red blood cells, the parasites multiply in a synchronized 48-hour cycle.

At the end of each multiplication cycle, the newly-formed parasites leave their host red blood cells, destroying them and infecting new ones. It is this destruction of red blood cells that causes the waves of fever associated with malaria. Severe forms of malaria are linked to the obstruction of blood vessels by infected red blood cells.

When a mosquito bites a human whose blood is infected with Plasmodium, the parasite changes its development program to colonize the intestine of its new host. After a further period of multiplication, Plasmodium returns to the mosquito's salivary glands, ready to infect a new human.

From the warmth of the red blood cell to the depths of the mosquito's intestine via the liver, how does Plasmodium perceive changes in its environment in order to change its development program? Understanding this very specific biological mechanism is an important step towards countering the parasite.

Part 1

At each stage of its life cycle, the parasite must logically pick up signals that enable it to react correctly.

There are small molecules  absent in the blood but present in the mosquito that the parasite is able to detect. Starting from this single known element, scientists have identified a sensor that enables the parasite to detect the presence of these molecules when it is ingested by a mosquito.

This sensor is made up of five proteins. In its absence, the parasite does not realize that it has left the bloodstream for the mosquito, and is therefore unable to continue its development.

Surprisingly, this sensor is also present at other stages of the parasite lifecycle, notably when the parasite has to leave the red blood cell. Scientists then observe exactly the same mechanism: without this sensor, Plasmodium is trapped in the red blood cells, unable to continue its infection cycle.

The protein complex discovered here is absent in humans, but is found in the entire family of apicomplexan parasites to which Plasmodium belongs, as well as Toxoplasma, the agent of toxoplasmosis. By identifying this sensor, scientists can now imagine how to scramble the signals perceived by the parasite at different stages of its development, thus disorienting it and blocking its multiplication and transmission.

Ronja Kühnel et al, A Plasmodium membrane receptor platform integrates cues for egress and invasion in blood forms and activation of transmission stages, Science Advances (2023). DOI: 10.1126/sciadv.adf2161. www.science.org/doi/10.1126/sciadv.adf2161

Part 2

NASA finds key building block for life in a moon of Saturn

Scientists have discovered that phosphorus, a key building block of life, lies in the ocean beneath the icy surface of Saturn's moon Enceladus. The finding was based on a review of data collected by NASA's Cassini probe, and was published Wednesday in the prestigious journal Nature.

Cassini started exploring Saturn and its rings and moons in 2004, before burning up in the gas giant's atmosphere when its mission ended in 2017.

NASA found abundant phosphorus in plume ice samples spraying out of the subsurface ocean.

Scientists previously found other minerals and organic compounds in the ejected ice grains, but not phosphorus, which is an essential building block for DNA and RNA, and is also found in the bones and teeth of people, animals, and even ocean plankton.

Simply put, life as we know it would not be possible without phosphorus.

It's the first time this essential element has been discovered in an ocean beyond Earth.

With this finding, the ocean of Enceladus is now known to satisfy what is generally considered to be the strictest requirement for life. The next step is clear –- we need to go back to Enceladus to see if the habitable ocean is actually inhabited.

Frank Postberg, Detection of phosphates originating from Enceladus's ocean, Nature (2023). DOI: 10.1038/s41586-023-05987-9. www.nature.com/articles/s41586-023-05987-9