As dengue expands beyond the global 'dengue belt,' scientists dispel conventional wisdom about the disease

Unknowns, dangers and surprises persist about dengue viral infection and now an assumption once accepted as conventional wisdom about immunity to the mosquito-borne disease may be incorrect.

Dengue is a devastating viral infection transmitted to humans through the bite of Aedes aegypti mosquitoes—flying hypodermic needles that descend prolifically during significant outbreaks. Many dengue epidemics tend to occur in urban settings, scientists say. Dengue viral infection can cause a severe headache, high fever, nausea, vomiting, swollen glands, and rash. Still, and perhaps most surprisingly, many people who are infected have no symptoms at all. In rare cases, however, dengue disease can be fatal.

New research involving epidemiological models and data from more than 4,400 people in Nicaragua suggests that it's time immunologists developed a new framework to understand population immunity to dengue. For decades, it was believed that once you were infected with dengue virus, the immunity lasted for life. The dogma persisted in the face of observational data, which found that people who were previously infected were more susceptible to severe dengue if infected again.

But an international collaborative group of researchers has now conclusively shown that immunity not only wanes, it tends to wax and wane—a discovery that reveals dengue infection to be far more complex than previously thought.

According to them, Infection with multiple dengue virus serotypes is thought to induce enduring protection against dengue disease. However, long-term antibody waning has been observed after repeated dengue infection. The waning of antibodies inevitably was followed by a boosting of antibodies when the next epidemic came along.

This discovery allowed the construction of a new model that best describes population vulnerability to dengue infection, especially amid the known periodicity—the cyclic nature—of dengue outbreaks.

When it comes to dengue, people are not permanently immune but susceptible to infection, then immune and ultimately susceptible again. Hence, the researchers  newly proposed a model: "susceptible-infected-recovered-susceptible."

Rosemary A. Aogo et al, Effects of boosting and waning in highly exposed populations on dengue epidemic dynamics, Science Translational Medicine (2023). DOI: 10.1126/scitranslmed.adi1734

New research suggests cellular stress in the placenta may be possible cause of preeclampsia

Preeclampsia is a mysterious condition that occurs in about one of 10 pregnancies without any early warning signs. After 20 weeks or more of normal blood pressure during the pregnancy, patients with preeclampsia will begin to experience elevated blood pressure and may also have increased levels of protein in their urine due to hypertension reducing the filtering power of the kidneys. Prolonged hypertension due to preeclampsia can lead to organ damage and life-threatening complications for mothers and fetuses.

There is no cure for the underlying causes of preeclampsia, so physicians focus on managing and monitoring patients' blood pressure to allow for as close to a full-term gestation as possible. With severe disease, pre-term deliveries are necessary.

For those who get it earlier on, it can be terrifying and life-changing, potentially including a long hospital stay before delivery and significant supportive care for the infant in the NICU afterwards.

Now scientists have published results on a study of one of the emerging theories for what causes preeclampsia in Science Advances.

The experiments focus on a particular layer of cells of the placenta called the syncytiotrophoblast (STB), which is a key part of the barrier between the mother and developing fetus. This blockade helps keep a mother's fully formed immune system from reacting to the fetus and potentially responding as if the fetus was a foreign threat such as a viral or bacterial invader.

The barrier also works in reverse to keep the fetus's growing immune system from reacting to its mother's cells and tissues. The study's authors investigated the hypothesis that an abnormal amount of cellular and molecular stresses to the STB can damage the placenta and lead to preeclampsia.

Part 1

By comparing "normal" placentas with placentas from pregnancies where patients suffered from preeclampsia, investigators demonstrated that preeclampsia was associated with higher levels of cellular stresses in the STB layer on the placenta. Additionally, the researchers found a hyperactive level of activity of the Gαq protein known to play a role in transmitting signals related to the levels of several hormones present in excessive amounts during preeclampsia.

So, can preeclampsia be prevented? While today the answer is no, MCW scientists now are one step closer with these experimental results. And they are continuing to work as a team to achieve this goal through additional studies.

Megan Opichka et al, Mitochondrial-Targeted Antioxidant Attenuates Preeclampsia-Like Phenotypes Induced by Syncytiotrophoblast-Specific Gαq Signaling, Science Advances (2023). DOI: 10.1126/sciadv.adg8118. www.science.org/doi/10.1126/sciadv.adg8118

Part 2

New discovery: Stunning River of Stars Flowing Through Space

A stunning river of stars has been spotted flowing through the intergalactic space in a cluster of galaxies about 300 million light years away.

Such bridges are known as stellar streams; and, at a length of 1.7 million light-years, the newly named Giant Coma Stream is the longest we've ever seen. And that's not all: the faint river is the first of its kind ever seen outside of a galaxy.

https://www.aanda.org/articles/aa/full_html/2023/11/aa46780-23/aa46...

Dolphins can detect electrical fields

Two captive bottlenose dolphins (Tursiops truncatus) have now proved to researchers at the University of Rostock and Nuremberg Zoo in Germany that they can reliably sense weak electric fields in the water with their long snouts.

The discovery hints at the possibility that some marine mammals really can sniff out the electric currents of small prey buried in the sand. They might even use the skill to sense Earth's magnetic field.

To date, only one other 'true' placental mammal on Earth has been found to possess electroreceptors. Little more than a decade ago, scientists demonstrated that the common Guiana dolphin (Sotalia guianensis) evolved its own unique system of electroreception – one that is inherently different to fish, amphibians, and monotremes, like platypuses and echidnas.

Experiments now suggest that adult bottlenose dolphins and Guiana dolphins can both do something oddly similar with a line of sensitive pores on their snouts, called vibrissal crypts. These little holes used to hold juvenile whiskers, and they are extremely sensitive.

In experiments, bottlenose dolphins were able to use these ex-whisker pits to sense very weak electric fields as low as 2.4 and 5.5 microvolts per centimeter – a detection threshold that the researchers say is "in the same order of magnitude as those in the platypus" and also similar to Guiana dolphins.

https://journals.biologists.com/jeb/article/226/22/jeb245845/334721...

Food Preserving Technique May Have Sparked Human Brain Growth: Researchers

Researchers propose that a taste for fermented morsels may have triggered a surprising jump in the growth rate of our ancestors' brains.

In fact, a shift from a raw diet to one that included food items already partially broken down by microbes may have been a crucial event in our brain's evolution, according to a perspective study by evolutionary neuroscientists.

Human brains have tripled in size over the last two million years of evolution, while human colons have shrunk by an estimated 74 percent, suggesting a reduced need to break down plant-derived food internally.
We know the timeline and extent of human brain expansion, but the mechanisms allowing energy to be directed to this expansion are more complex and somewhat debated.

The study authors lay out their "external fermentation hypothesis" which shows our ancestors' metabolic circumstances for selective brain expansion may have been set in motion by moving intestinal fermentation to an external process, perhaps even experimenting with preserved foods not unlike the wine, kimchi, yoghurt, sauerkraut, and other pickles we still eat today.
The human gut microbiome acts like a machine for internal fermentation, which boosts nutrient absorption during digestion. Organic compounds are fermented into alcohol and acids by enzymes, usually produced by the bacteria and yeasts that live in parts of our digestive system such as our colon.
Fermentation is an anaerobic process, meaning it doesn't require oxygen, so similar to the process in our guts, it can occur in a sealed container. The process produces energy in the form of adenosine triphosphate (ATP), which is an essential source of chemical energy that powers our metabolism.

The researchers argue it's possible that culturally passed-down ways of handling or storing food encouraged this function to be externalized.

Externally fermented foods are easier to digest and contain more available nutrients than their raw equivalents. And since there's less for the colon to do if the food is already fermented, the organ's size could reduce over time while still potentially leaving energy available for brain growth.
Part 1

The brain sizes of our ancestors, the Australopiths, were similar to those of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). The human lineage's brain expansion accelerated with Homo's emergence and continued through Homo sapiens and Homo neanderthalensis.

How did our ancestors, with brains about the size of chimpanzees, manage to harness the power of external fermentation?

Researchers suggest that hominids with lower cognitive abilities and smaller brains may have adapted to fermentation much earlier than proposed alternative alternative explanations for this gut-to-brain energy redirection, like animal hunting and fire-based cooking.
Fermentation has many advantages associated with cooked foods, such as softer textures, increased caloric content, improved nutrient absorption, and defense against harmful microorganisms.
The researchers emphasize the need for empirical research to support or refute their hypothesis, such as microbiological studies, comparative analyses, and genetic and genomic investigations.

https://www.nature.com/articles/s42003-023-05517-3

Part 2

**

Brain implants revive cognitive abilities long after traumatic brain injury in clinical trial

A lady in her final semester of college, planning to apply to law school, when she suffered a traumatic brain injury in a car accident. The injury so compromised her ability to focus she struggled in a job sorting mail.

She couldn't remember anything . Her left foot dropped, so she'd trip over things all the time. She was always in car accidents. And she had no filter—she'd get pissed off really easily.

Her parents learned about research being conducted at Stanford Medicine and reached out; she was accepted as a participant. In 2018, physicians surgically implanted a device deep inside her brain, then carefully calibrated the device's electrical activity to stimulate the networks the injury had subdued. The results of the clinical trial were published Dec. 4 in Nature Medicine. She noticed the difference immediately. When she was asked to list items in the produce aisle of a grocery store, she could rattle off fruits and vegetables. Then a researcher turned the device off, and she couldn't name any. Since the implant she hadn't  had any speeding tickets she said. She doesn't trip anymore. She can remember how much money is in her bank account. She  wasn't able to read earlier, but after the implant she bought a book, 'Where the Crawdads Sing,' and loved it and remembered it. And she doesn't have that quick temper." For her and four others, the experimental deep-brain-stimulation device restored, to different degrees, the cognitive abilities they had lost to brain injuries years before. The new technique, developed by Stanford Medicine researchers and collaborators from other institutions, is the first to show promise against the long-lasting impairments from moderate to severe traumatic brain injuries.

Nicholas Schiff, Thalamic deep brain stimulation in traumatic brain injury: a phase 1, randomized feasibility study, Nature Medicine (2023). DOI: 10.1038/s41591-023-02638-4. www.nature.com/articles/s41591-023-02638-4

Toxic chemicals in  whales and dolphins are exceeding safe limits

Almost half of marine mammals around the UK are being poisoned by banned chemicals.

The compounds, once used in pesticides, flame retardants and coolants, are having significant impacts on the health and reproduction of the animals.

The UK's whales and dolphins are full of toxins—and it might only get worse.

Despite many being banned almost 20 years ago, levels of persistent organic pollutants (POPs) remain high in the oceans. In fact, these chemicals may breach safe limits in as many as half of all marine mammals living around the UK, based on a new study of stranded animals.

While the researchers found that levels of six key POPs are declining, they're concerned that the chemicals currently contained in coastal landfill sites could increasingly leak out as flooding, extreme weather and coastal erosion are enhanced by climate change.

What is alarming is this can happen anywhere in the world.

Rosie S. Williams et al, Spatiotemporal Trends Spanning Three Decades Show Toxic Levels of Chemical Contaminants in Marine Mammals, Environmental Science & Technology (2023). DOI: 10.1021/acs.est.3c01881

Cracked Piece of Metal Heals Itself in Experiment 

Scientists observed a metal healing itself, something never seen before. If this process can be fully understood and controlled, we could be at the start of a whole new era of engineering.

In a study published in July, a research team  was testing the resilience of the metal, using a specialized transmission electron microscope technique to pull the ends of the metal 200 times every second. They then observed the self-healing at ultra-small scales in a 40-nanometer-thick piece of platinum suspended in a vacuum. Cracks caused by the kind of strain described above are known as fatigue damage: repeated stress and motion that causes microscopic breaks, eventually causing machines or structures to break. Amazingly, after about 40 minutes of observation, the crack in the platinum started to fuse back together and mend itself before starting again in a different direction.

https://www.nature.com/articles/s41586-023-06223-0

Eye scans can provide crucial insights into kidney health, study finds

3D eye scans can reveal vital clues about kidney health that could help to track the progression of disease, research suggests. The advance could revolutionize the monitoring of kidney disease, which often progresses without symptoms in the early stages.

Experts say the technology has the potential to support early diagnosis as current screening tests cannot detect the condition until half of the kidney function has been lost. Researchers used highly magnified images to detect changes to the retina—the layer of tissue at the back of the eye that senses light and sends signals to the brain. They found that the images offer a quick, non-invasive way to monitor kidney health.

The eye is the only part of the body where it is possible to view a key process called microvascular circulation—and this flow of blood through the body's tiniest vessels is often affected in kidney disease.

 investigated whether 3D images of the retina, taken using a technology called optical coherence tomography (OCT), could be used to identify and accurately predict the progression of kidney disease.

OCT scanners—used in most high street opticians—use  light waves to create a cross-sectional picture of the retina, displaying each individual layer, within a few minutes.

The team looked at OCT images from 204 patients at different stages of kidney disease, including transplant patients  alongside 86 healthy volunteers. They found that patients with chronic kidney disease had thinner retinas compared with healthy volunteers. The study also showed that thinning of the retina progressed as kidney function declined.

These changes were reversed when kidney function was restored following a successful transplant. Patients with the most severe form of the disease, who received a kidney transplant, experienced rapid thickening of their retinas after surgery.

This knowledge can be utilized in the future to identify the kidney ailments fast.

 Neeraj Dhaun et al, Choroidal & retinal thinning in chronic kidney disease are modifiable with treatment & independently associate with eGFR decline, Nature Communications (2023). www.nature.com/articles/s41467-023-43125-1

Harvesting water from air with solar power

More than 2.2 billion people currently live in water-stressed countries, and the United Nations estimates that 3.5 million die every year from water-related diseases. Because the areas most in need of improved drinking water are also located in some of the sunniest places in the world, there is strong interest in harnessing sunlight to help obtain clean water.

Researchers  developed a promising new solar-powered atmospheric water harvesting technology that could help provide enough drinking water for people to survive in those difficult, dryland areas.

Historically, researchers have faced challenges when injecting salt into hydrogels as the higher salt content reduced the swelling capacity of the hydrogel due to the salting-out effect. This led to salt leakage and the water absorption capacity decreased.

The researchers synthesized a super hygroscopic gel using plant derivatives and hygroscopic salts that was capable of absorbing and retaining an unparalleled amount of water. One kilogram of dry gel could adsorb 1.18 kilograms of water in arid atmospheric environments and up to 6.4 kilograms in humid atmospheric environments. This hygroscopic gel was simple and inexpensive to prepare and would consequently be suitable for large-scale preparation.

In addition, the team adopted a prototype with desorption and condensation chambers, configured in parallel. They employed a turbofan in the condensation chamber to increase the recovery of desorbed water to more than 90%.

In an outdoor prototype demonstration, the team found it released adsorbed water even in the morning or afternoon when the sun is weak. The system could also achieve simultaneous adsorption and desorption during the daytime.

The team is trying to work to achieve simultaneous adsorption and desorption using renewable energy  to maximize daily water yield per unit mass of adsorbent to further optimize the system's performance for practical applications in water generation.

Chengjie Xiang et al, Daytime air-water harvesting based on super hygroscopic porous gels with simultaneous adsorption-desorption, Applied Physics Reviews (2023). DOI: 10.1063/5.0160682

Replacing bone saws with smart lasers

Even back in 1957, when Gordon Gould coined the term "laser" (short for "Light Amplification by Stimulated Emission of Radiation"), he was already imagining the possibilities for its use in medicine. Surgeons would be able to make precise incisions without even touching the patient.

Before that could happen, however, there were—and still are—many hurdles to overcome. Manually controlled light sources have been superseded by mechanical and computer-controlled systems to reduce injuries caused by clumsy handling. Switching from continuous beams to pulsed lasers, which turn themselves rapidly on and off, has reduced the heat they produce. Technical advances allowed lasers to enter the world of ophthalmology in the early 1990s. Since then, the technology has moved on in other areas of medicine, too, but only in relatively few applications has it replaced the scalpel and the bone saw.

Safety concerns are the most important hurdle: how can we prevent injury to the surrounding tissue? How closely can the cutting depth be controlled so that deeper layers of tissue are not accidentally damaged?

Researchers  have just made an important contribution to the safe and precise use of lasers with their recent publication in the journal Lasers in Surgery and Medicine. They  developed a system that combines three functions: it cuts bone, controls the cutting depth and differentiates between different tissues.

These three functions are carried out by three lasers that are aligned to focus on the same spot. The first laser serves as a tissue sensor in that it scans the surroundings of the site where the bone is to be cut.

Pulses are sent with this laser to the surface at regular intervals, so to speak, vaporizing a tiny bit of tissue each time. The composition of this vaporized tissue is measured with a spectrometer. Each type of tissue has its own individual spectrum—its own signature. An algorithm processes this data and creates a kind of map that shows where the bones are located and where the soft tissue is.

Not until all of this has been completed does the second laser, which cuts bone, activate, and then only in places where bones rather than soft tissue are shown on the map that has just been generated. At the same time, the third laser—an optical system—measures the depth of the cut and checks that the cutting laser is not penetrating more deeply than planned. During the cutting phase, the tissue sensor also constantly monitors whether the correct tissue is being cut.

The special thing about this system is that it controls itself—without human interference.

The researchers have so far been testing their system on femur bones and tissue from pigs acquired from a local butcher. They were able to prove that their system works accurately down to fractions of a millimeter. The speed of the combined laser also approaches that of a conventional surgical procedure.

The research team is currently working on making the system smaller.

Arsham Hamidi et al, Multimodal feedback systems for smart laser osteotomy: Depth control and tissue differentiation, Lasers in Surgery and Medicine (2023). DOI: 10.1002/lsm.23732 Arsham Hamidi et al,

Towards miniaturized OCT-guided laser osteotomy: integration of fiber-coupled Er:YAG laser with OCT, Optics Continuum (2023). DOI: 10.1364/OPTCON.497483

Scientist Rebellion is composed of thousands of climate researchers, academics, and concerned citizens who are urging people to get involved in the effort to limit global overheating. As part of the COP 28 proceedings, Scientist Rebellion is urging people to sign an open letter pleading for governments to heed the climate science and take meaningful action while there is still time.

https://scientistrebellion.org/

https://cleantechnica.com/2023/12/05/1000-scientists-plead-for-publ...

**

The first ever 1,000-qubit quantum chip

IBM has unveiled the first quantum computer with 1,121 superconducting qubits (qubits are the quantum equivalent of digital bits in a classical computer). Quantum computers could outperform classical computers in certain areas by exploiting phenomena such as entanglement and superposition. However, these quantum states are notoriously fickle and prone to error, so simply having more qubits does not necessarily make a system better. IBM says it will now focus on more error-resistant systems, rather than larger ones.

https://www.nature.com/articles/d41586-023-03854-1?utm_source=Live+...

Earliest mosquito was a bloodsucking male
The discovery of the earliest known fossil mosquitoes, preserved in Lebanese amber, had a sting in the tail: the insects were bloodsucking males. Today, only female mosquitoes eat blood, with males living on nectar and plant juices. The 125-million-year-old fossils have mouthparts that look perfect for piercing skin, as well as mate-grabbing appendages that confirm their sex. The finding could turn current thinking — that blood-sucking evolved after plant-eating — on its head. “We think now that, originally, the mosquito could be bloodsucking,” says palaeontologist and study co-author Dany Azar. “With the appearance of the flowering plant, this function could be just forgotten later on.”

https://www.sciencedirect.com/science/article/pii/S0960982223014483...

Is Dementia contagious?

Could Blood Transfusions and Tissue Transplants Spread Certain Dementias?

In the last several years, scientists have begun investigating whether neurodegenerative diseases like Alzheimer’s and Parkinsons can be contagious. One misfolded protein, scientists hypothesize, might somehow ensnare other proteins and cause them to misfold, leading to plaque build-up in the brain. If a malfunctioning protein somehow finds its way into another individual, could it launch a similar accumulation of proteins?

What they've found: In 2015 researchers reported a curious buildup of the protein plaque associated with some dementias in young to middle-age adults who had received childhood injections of human growth hormone extracted from the pituitary glands of cadavers. And in 2018 doctors recorded unusual cases of cerebral amyloid angiopathy, a condition marked by amyloid buildup in cerebral blood vessels; because these young adults had brain surgery in childhood, the researchers suspect that contaminated surgical tools transferred the “seeds” of plaque accumulation to the patients’ brains.

Why this matters: Learning how prionlike diseases “spread” might launch treatments that interrupt their replication and accumulation. Early studies in mice have shown that amyloid antibodies can clear plaque build up, which aligns with recent trials of new Alzheimer’s treatments that show how removing brain amyloid can slow cognitive decline. If protein misfolding is contagious, we may have a new way to interrupt the devastation it causes.

https://www.scientificamerican.com/article/could-blood-transfusions...

Research shows mouse and primate brains mature at same pace

A new study  has revealed that short-lived mice and longer-living primates develop brain synapses on the exact same timeline, challenging assumptions about disease and aging. What does this mean for humans—and yesterday's research?

Mice typically live two years and monkeys live 25 years, but the brains of both appear to develop their synapses at the same time. This finding, the result of a recent study  has puzzled neuroscientists.

Until now, brain development was understood as happening faster in mice than in other, longer-living mammals such as primates and humans. Those studying the brain of a 2-month-old mouse, for example, assumed the brain was already finished developing because it had a shorter overall lifespan in which to develop. In contrast, the brain of a 2-month-old primate was still considered going through developmental changes. Accordingly, the 2-month-old mouse brain was not considered a good comparison model to that of a 2-month-old primate. That assumption appears to be completely wrong, which the authors think will call into question many results using young mouse brain data as the basis for research into various human conditions, including autism and other neurodevelopmental disorders.

Gregg Wildenberg et al, Isochronic development of cortical synapses in primates and mice, Nature Communications (2023). DOI: 10.1038/s41467-023-43088-3

New study concludes finding cure for malaria may be even more challenging than thought

Researchers who have studied malaria for decades, hoping to find a cure, long thought they'd identified a type of blood that seemed to defend against the disease. But a new study published in Cell Host & Microbe concludes that even some people with the protective blood type became infected. The question now is, how? "This might mean that the specific gene mutation related to this blood type doesn't completely stop malaria, or the malaria bug might have found another way to get into the blood cells," said Peter Zimmerman, a pathology professor at Case Western Reserve University School of Medicine and the study's senior author. "It's a big deal because it might change how we try to get rid of this type of malaria parasite." "This malaria parasite, called Plasmodium vivax—or P. vivax—used to be common in Northeast Ohio," said Christopher King, a study co-investigator and pathology professor. "And it was transmitted within the United States—Florida and Texas—this summer for the first time in 20 years.

"We have known," King said, "that the United States is at risk of re-introduction of malaria with climate changes and increasing immigration and traveling from malaria-endemic areas."
Study collaborators include researchers from France (Célia Dechavanne and Benoit Gamain, from the National Institute of Blood Transfusion, INSERM/Paris Diderot University); and Madagascar (Arsène Ratsimbasoa, from the University of Fianarantsoa).
Part 1

"Malaria researchers have been trying to chip away at understanding resistance and susceptibility of P. vivax infection of African people for more than 100 years," Zimmerman said. "More than 2.5 billion people may live in Africa and Southeast Asia where the parasite is found. Hundreds of thousands of people a year die from malaria. In general, malaria is one of the big three global-health infectious diseases—malaria, tuberculous and HIV/AIDS."

The team is studying a specific blood type (Fy-negative) in the blood of most people in Africa and of African origin, called "the silent Duffy blood group." Duffy-negative people have a mutation in the DNA code (GATA-1) that results in the protein not being expressed on the surface of red blood cells.

The researchers did experiments using blood cells grown in the lab and cells taken from bone marrow to study the Duffy-silent blood type.

"Surprisingly, we found that even when people are missing the GATA-1 DNA code, the Duffy protein sometimes shows up on their red blood cells," Zimmerman said. "Our findings suggest that the bone marrow and other places where blood cells are first made are important for the malaria parasite to find the red cells with the Duffy protein, to grow and cause sickness."

In other experiments in the lab, they examined the blood of people with Duffy silent blood type. They noticed the P. vivax malaria infection was often detected using a special test rather than the usual microscope test.

This means that people with Duffy-silent blood type can still have the infection, but it's not always easy to see in regular blood tests. In other words, they found that P. vivax can invade the red blood cells of people with the Duffy-silent trait. Also, if they have the infection in the bone marrow, they produce the transmissible form of the parasite. Mosquitoes can acquire it and cause infections in other people.

"This discovery raises questions about how malaria parasites cause infection and sickness, especially because some people with the infection don't show many signs in their blood," Zimmerman said. "We need to look at the blood more closely to understand better how widespread and serious this type of malaria is in people with the Duffy-silent trait."

Celia Dechavanne et al, Duffy antigen is expressed during erythropoiesis in Duffy-negative individuals, Cell Host & Microbe (2023). DOI: 10.1016/j.chom.2023.10.019

Part 2

**

Study finds sleep can improve memory retention but can also imprint false memories

A team of psychologists has found via experimentation that sleeping after studying can consolidate memories. But, as they note in their paper published in the journal Royal Society Open Science, sleep can also sometimes lead to the creation of false memories.

Recent research efforts have shown that human memory is not nearly as accurate as it may feel to someone who is recalling a memory of a thing or event—findings that have called into question eyewitness accounts at criminal trials. Such results have led to more study of memory retention and recall as a way to learn more about the ways that memory works.

For this new research, 488 volunteers studied a list of related words and then to attempt to recall those words 12 hours later. To learn about the impact of sleep on retention, some of the volunteers were allowed to sleep between the time they viewed the original list and the time of the memory retention testing.

The researchers found that those people who were allowed to sleep during the interim scored better on memory retention. But they also found that they were more likely to believe falsely that some related words were on the list. As an example, when given a list such as "nurse, hospital and surgery," people who had been allowed to sleep were more likely to falsely believe the word "doctor" had also appeared on the list.

The researchers suggest this finding shows that the purpose of memory is not necessarily to give people an accurate assessment of things that have occurred, but to give them a means for retrieving the gist of things. As humans evolved, it was important that connections and associations be made as part of the learning process in order to better prepare for future threats.

The research team also found that the time of day the volunteers were questioned about the list had an impact on recall accuracy—both groups made more errors and falsely recalled more words when questioned during the evening.

Matthew H. C. Mak et al, A registered report testing the effect of sleep on Deese-Roediger-McDermott false memory: greater lure and veridical recall but fewer intrusions after sleep, Royal Society Open Science (2023). DOI: 10.1098/rsos.220595

A possible way for early life on Earth to survive cosmic radiation

A team of biophysicists  has uncovered via experimentation the means by which early life might have been able to survive cosmic radiation. In their study, reported in the journal Nature Communications, the group conducted experiments with radiation-resistant manganese antioxidants.

Prior research has shown that the Earth was formed approximately 4.5 billion years ago, and that life arose approximately a half-billion years later. Prior research has also shown that the Earth's magnetic field did not start protecting life from cosmic radiation until approximately 3.5 billion years ago. This leads to questions about how life was able to begin and flourish in those early years.

A type of bacteria known as Deinococcus radiodurans has been shown to be capable of surviving levels of radiation that would kill most other living creatures. Study of this bacteria reveals that it is able to do so because of the amount of Mn(II) (manganese) ions in its body—it serves to protect the tiny creatures from the oxidative stress that would occur in other bacteria that do not have it. This finding has led to theories that suggest harboring of Mn(II) ions is the means by which early life survived on Earth.

To test this theory, the research team created models they describe as protocells—such "coacervates" were used to serve as stand-ins for early life protocells on Earth. The team used two types, one based on polyphosphate manganese, the other based on polyphosphate peptides. When exposed to high levels of gamma rays, the polyphosphate–manganese coacervates remained intact and viable. The polyphosphate–peptide coacervates, on the other hand, were destroyed. Prior research has shown that polyphosphate manganese has been present on Earth longer than life has existed, likely produced during volcanic activity—thus, it would have been available for use by protocells as a means of protection. The researchers suggest that early protocells on Earth were able to survive due to protection by material similar to polyphosphate manganese. Such protocells, they note, would have been able to survive long enough to develop into cyanobacteria and eventually eukaryotic cells, which would have been protected by the Earth's magnetic field and ozone layer.

Shang Dai et al, An inorganic mineral-based protocell with prebiotic radiation fitness, Nature Communications (2023). DOI: 10.1038/s41467-023-43272-5

Plant Hormone That Can Boost Plant Growth By 30%

Researchers show that an influx of water and salts propel immune cells through the body

Researchers have shown that an influx of water and ions into immune cells allows them to migrate to where they're needed in the body.

Our bodies respond to illness by sending out chemical signals called chemokines, which tell immune cells called T cells where to go to fight the infection. This process had already been associated with a protein called WNK1, which activates channels on the cell surface,  allowing ions (salts like sodium or potassium) to move into cells. Until now, it was not clear why ion influx was needed for T cells to move.

Through a study published in Nature Communications, the researchers imaged mouse T cells and observed that, following a chemokine signal, WNK1 is activated at the front of the cells, called the "leading edge." The team showed that the activation of WNK1 opens channels on the leading edge, resulting in an influx of water and ions. They propose that this flow of water causes the cells to swell on the front side, creating space for the 'actin cytoskeleton'—the scaffolding inside the cell that holds its structure—to grow into. This propels the whole cell forward and the process repeats again. The researchers used gene editing to stop mice producing WNK1, or an inhibitor to prevent WNK1's activity, observing that the T cells in these mice slowed down or stopped moving completely. Importantly, they found that they could make up for the loss of WNK1 and make the cells speed up by dropping them into a watery solution, which causes the cells to take up water and swell. This shows that the uptake of water, controlled by the WNK1 protein is key for the cells to migrate.

The researchers think that the mechanism they've discovered could be involved in lots of different cell types beyond immune cells.

Leonard L. de Boer et al, T cell migration requires ion and water influx to regulate actin polymerization, Nature Communications (2023). DOI: 10.1038/s41467-023-43423-8

Study finds climate change can cause methane to be released from the deep ocean

New research has shown that fire-ice—frozen methane which is trapped as a solid under our oceans—is vulnerable to melting due to climate change and could be released into the sea.

An international team of researchers found that as frozen methane and ice melts, methane—a potent greenhouse gas—is released and moves from the deepest parts of the continental slope to the edge of the underwater shelf. They even discovered a pocket that had moved 25 miles (40 kilometers). Publishing in the journal Nature Geoscience, the researchers say this means that much more methane could potentially be vulnerable and released into the atmosphere as a result of climate warming.

Methane hydrate, also known as fire-ice, is an ice-like structure found buried in the ocean floor that contains methane. Vast amounts of methane are stored as marine methane under oceans. It thaws when the oceans warm, releasing methane into oceans and the atmosphere—known as dissociated methane—contributing to global warming.

The scientists used advanced three-dimensional seismic imaging techniques to examine the portion of the hydrate that dissociated during climatic warming off the coast of Mauritania in Northwest Africa. They identified a specific case where dissociated methane migrated over 40 kilometers and was released through a field of underwater depressions, known as pockmarks, during past warm periods.

Long-distance migration and venting of methane after marine hydrate dissociation, Nature Geoscience (2023). DOI: 10.1038/s41561-023-01333-w. www.nature.com/articles/s41561-023-01333-w

Planet tipping points pose 'unprecedented' threat to humanity: report

Humanity faces an "unprecedented" risk from tipping points that could unleash a domino effect of irreversible catastrophes across the planet, researchers warned this week.

The most comprehensive assessment ever conducted of Earth's invisible tripwires was released as leaders meet for UN climate talks in Dubai with 2023 set to smash all heat records. While many of the 26 tipping points laid out in the report—such as melting ice sheets—are linked to global warming, other human activities like razing swathes of the Amazon rainforest could also push Earth's ecosystems to the brink. Five of these are showing signs of tipping—from melting ice sheets threatening catastrophic sea level rise, to mass die-off of tropical coral reefs—the report warned. Some may have already begun to irrecoverably transform. Once the world crosses the threshold for just one tipping point, dealing with the immediate humanitarian disaster could distract attention away from stopping the others, creating a "vicious cycle" of mass hunger, displacement and conflict, the report warned.

The risks for humanity in crossing tipping points into these unexplored states is dire, and the impact to human lives potentially horrific.

Source: News agencies

Warfare ruins the environment—and not just on the front lines

On the morning of December 6, 1917, a French cargo ship called SS Mont-Blanc collided with a Norwegian vessel in the harbor of Halifax in Nova Scotia, Canada. The SS Mont-Blanc, which was laden with 3,000 tons of high explosives destined for the battlefields of the first world war, caught fire and exploded. The resulting blast released an amount of energy equivalent to roughly 2.9 kilotons of TNT, destroying a large part of the city. Although it was far from the front lines, this explosion left a lasting imprint on Halifax in a way that many regions experience environmental change as a result of war. The attention of the media is often drawn to the destructive explosions caused by bombs, drones or missiles. And the devastation we have witnessed in cities like Aleppo, Mosul, Mariupol and now Gaza certainly serve as stark reminders of the horrific impacts of military action. However, research is increasingly uncovering broader and longer-term consequences of war that extend well beyond the battlefield. Armed conflicts leave a lasting trail of environmental damage, posing challenges for restoration after the hostilities have eased.

https://theconversation.com/warfare-ruins-the-environment-and-not-j...

Ancient stars made extraordinarily heavy elements, researchers find

How heavy can an element be? An international team of researchers has found that ancient stars were capable of producing elements with atomic masses greater than 260, heavier than any element on the periodic table found naturally on Earth. The finding deepens our understanding of element formation in stars.

We are, literally, made of star stuff. Stars are element factories, where elements constantly fuse or break apart to create other lighter or heavier elements. When we refer to light or heavy elements, we're talking about their atomic mass. Broadly speaking, atomic mass is based on the number of protons and neutrons in the nucleus of one atom of that element.
The heaviest elements are only known to be created in neutron stars via the rapid neutron capture process, or r-process. Picture a single atomic nucleus floating in a soup of neutrons. Suddenly, a bunch of those neutrons get stuck to the nucleus in a very short time period—usually in less than one second—then undergo some internal neutron-to-proton changes, and voila! A heavy element, such as gold, platinum or uranium, forms.

The heaviest elements are unstable or radioactive, meaning they decay over time. One way that they do this is by splitting, a process called fission.

The r-process is necessary if you want to make elements that are heavier than, say, lead and bismuth.
You have to add many neutrons very quickly, but the catch is that you need a lot of energy and a lot of neutrons to do so. And the best place to find both are at the birth or death of a neutron star, or when neutron stars collide and produce the raw ingredients for the process.
The team took a fresh look at the amounts of heavy elements in 42 well-studied stars in the Milky Way. The stars were known to have heavy elements formed by the r-process in earlier generations of stars. By taking a broader view of the amounts of each heavy element found in these stars collectively, rather than individually as is more common, they identified previously unrecognized patterns.
Part 1

Those patterns signaled that some elements listed near the middle of the periodic table—such as silver and rhodium—were likely the remnants of heavy element fission. The team was able to determine that the r-process can produce atoms with an atomic mass of at least 260 before they fission.

That 260 is interesting because we haven't previously detected anything that heavy in space or naturally on Earth, even in nuclear weapon tests.

 Ian U. Roederer et al, Element abundance patterns in stars indicate fission of nuclei heavier than uranium, Science (2023). DOI: 10.1126/science.adf1341. www.science.org/doi/10.1126/science.adf1341

Part 2

Physicists 'entangle' individual molecules for the first time, hastening possibilities for quantum computing

For the first time, a team of  physicists have been able to link together individual molecules into special states that are quantum mechanically "entangled." In these bizarre states, the molecules remain correlated with each other—and can interact simultaneously—even if they are miles apart, or indeed, even if they occupy opposite ends of the universe. This research was recently published in the journal Science.

This is a breakthrough in the world of molecules because of the fundamental importance of quantum entanglement. And it is also a breakthrough for practical applications because entangled molecules can be the building blocks for many future applications.

These include, for example, quantum computers that can solve certain problems much faster than conventional computers, quantum simulators that can model complex materials whose behaviors are difficult to model, and quantum sensors that can measure faster than their traditional counterparts.

To entangle the molecules, they had to make the molecule interact. By using a series of microwave pulses, they were able to make individual molecules interact with one another in a coherent fashion.

By allowing the interaction to proceed for a precise amount of time, they were able to implement a two-qubit gate that entangled two molecules. This is significant because such an entangling two-qubit gate is a building block for both universal digital quantum computing and for simulation of complex materials.

Connor M. Holland et al, On-demand entanglement of molecules in a reconfigurable optical tweezer array, Science (2023). DOI: 10.1126/science.adf4272. www.science.org/doi/10.1126/science.adf4272

Yicheng Bao et al, Dipolar spin-exchange and entanglement between molecules in an optical tweezer array, Science (2023). DOI: 10.1126/science.adf8999. www.science.org/doi/10.1126/science.adf8999

Augusto Smerzi et al, Entanglement with tweezed molecules, Science (2023). DOI: 10.1126/science.adl4179. www.science.org/doi/10.1126/science.adl4179

Scientists create 'cloaked' donor cell, tissue grafts that escape immune system rejection

Immune rejection poses a major challenge in donor cell therapy. Transplant and cell therapy patients are required to take immunosuppressive drugs – sometimes for the rest of their lives – to prevent their bodies from rejecting the transplant. The extended use of these drugs can lead to serious health issues, including recurring infections and an elevated cancer risk.

Scientists worldwide have been exploring various solutions, including creating therapeutic cells from the patient’s own cells or encapsulating donor cells in inorganic material for protection.

But these methods face challenges such as high costs, long preparation times and foreign body immune response, complicating their widespread and cost-effective application.

Researchers now have developed a technology that may one day eliminate the need for immunosuppressive drugs in transplant patients.
Through genetic modification of donor cells, the researchers successfully created transplants that persisted long-term in pre-clinical testing without the need for immune suppression.
The findings raise hope that a similar strategy could be employed in human patients, potentially making transplantation safer and more widely available.

--

Stem cells have the unique ability to divide indefinitely and give rise to specialized cells that form our organs. They make an ideal source for cell therapies as large numbers of cells can be obtained and converted into desired cell types to replace those lost to disease or injury.

But there are major safety concerns: in addition to addressing immune-matching, scientists must ensure that no unwanted dividing cells remain in the transplant that could cause cancer in the future.

Researchers  selected eight key genes that regulate how the immune system responds to threats, including foreign cells. Forced overexpression of these genes in mouse embryonic stem cells prevented the immune system from recognizing them as foreign.

The modification effectively created an immune cloak around the cells following their injection under the skin of genetically unmatched hosts.

This study demonstrates the combined potential of FailSafe and immune cloaking for the creation of a universal source of cells that could be applied to a multitude of diseases.

Uncloaked cells are typically rejected within 10 days of transplantation. In contrast, the cloaked cells persisted for more than nine months at the endpoint of the experiment. This is the first time that  scientists have been able to achieve this length of time without rejection in a fully functional immune system.

In another key finding, the researchers showed that unmodified cells can escape rejection when embedded into the tissue created by the cloaked donor cells below the skin surface. The protection extended to cells from another species, as shown by the ability of unmodified human cells to survive within a cloaked mouse graft.

This suggests that modified cells also act as an immune-privileged implantation site for unmodified cells, with implications for interspecies transplants. Researchers at other institutions are exploring the potential of pigs as donors because their organs are very similar in size and function to humans.

https://www.nature.com/articles/s41551-023-01133-y

Study reveals genes that set humans apart from other primates in cognitive ability

An international team of researchers has uncovered over 100 genes that are common to primate brains but have undergone evolutionary divergence only in humans – and which could be a source of our unique cognitive ability.

They found the genes are expressed differently in the brains of humans compared to four of our relatives – chimpanzees, gorillas, macaques and marmosets.

The findings, published in Nature Ecology & Evolution, suggest that reduced selective pressure, or tolerance to loss-of-function mutations, may have allowed the genes to take on higher-level cognitive capacity. The study is part of the Human Cell Atlas, a global initiative to map all human cells to better understand health and disease.
This research contributes to our understanding of differences in the brain between humans and other primates at the cellular level, but it has also resulted in a database that can be used to further characterize genetic similarities and differences across primates.

In all, the team found 139 genes that are common across the primate groups but highly divergent in their expression in human brains. These genes displayed a stronger ability to withstand mutations without impacting their function, suggesting they may have evolved under more relaxed selective pressure.

The genes that have diverged in humans must be tolerant to change. This manifests as tolerance to loss-of-function mutations, and seems to allow for rapid evolutionary change in the human brain.

Our higher cognitive function may have resulted from the adaptive evolution of human brain cells to a multitude of less threatening mutations over time. It’s also worth noting that around a quarter of the human-divergent genes identified in the study are associated with various brain disorders.

The divergent genes the researchers identified are found in 57 brain cell types, grouped by inhibitory neurons, excitatory neurons and non-neurons. A quarter of the genes were only expressed differently in neuronal cells, also known as grey matter, and half were only expressed differently in glial cells, which are white matter.

Grey matter in the brain consists of neurons, while white matter consists of other cell types, including those responsible for vasculature and immune function.

 Hamsini Suresh et al, Comparative single-cell transcriptomic analysis of primate brains highlights human-specific regulatory evolution, Nature Ecology & Evolution (2023). DOI: 10.1038/s41559-023-02186-7

Self-copying RNA vaccine wins approval
Japanese regulators have approved a COVID-19 vaccine constructed using a form of RNA that can make copies of itself inside cells. It’s the first ‘self-amplifying’ RNA (saRNA) vaccine platform to be granted full regulatory approval anywhere in the world. Because it could be used at a lower dose, it might have fewer side effects than other messenger RNA (mRNA) treatments have. When used as a booster in clinical testing, the newly authorized vaccine, ARCT-154 — developed by US biotechnology firm Arcturus Therapeutics and Australia-based CSL — triggered higher levels of virus-fighting antibodies that circulated the body for longer than did a standard mRNA COVID-19 vaccine.

https://www.nature.com/articles/d41586-023-03859-w?utm_source=Live+...

Electricity from electric eels may transfer genetic material to nearby animals

 The electric eel is the biggest power-making creature on Earth. It can release up to 860 volts, which is enough to run a machine. In a recent study, a research group  found electric eels can release enough electricity to genetically modify small fish larvae. They published their findings in PeerJ.

The researchers' findings add to what we know about electroporation, a gene delivery technique. Electroporation uses an electric field to create temporary pores in the cell membrane. This lets molecules, like DNA or proteins, enter the target cell.

To test this, they exposed the young fish in their laboratory to a DNA solution with a marker that glowed in the light to see if the zebrafish had taken the DNA. Then, they introduced an electric eel and prompted it to bite a feeder to discharge electricity.

Electroporation might happen in nature.  Researchers realized that electric eels in the Amazon River could well act as a power source, organisms living in the surrounding area could act as recipient cells, and environmental DNA fragments released into the water would become foreign genes, causing genetic recombination in the surrounding organisms because of electric discharge.

The researchers discovered that 5% of the larvae had markers showing gene transfer. "This indicates that the discharge from the electric eel promoted gene transfer to the cells, even though eels have different shapes of pulse and unstable voltage compared to machines usually used in electroporation. Electric eels and other organisms that generate electricity could affect genetic modification in nature.

Other studies have observed a similar phenomenon occurring with naturally occurring fields, such as lightning, affecting nematodes and soil bacteria. 

Shintaro Sakaki et al, Electric organ discharge from electric eel facilitates DNA transformation into teleost larvae in laboratory conditions, PeerJ (2023). DOI: 10.7717/peerj.16596

The zebrafish larvae and a DNA solution were put into a small container and placed inside the tank where the electric eel produces electric pulses when it is fed by the experimenter.

Part 2

Six-million-year-old groundwater pool discovered deep under Sicilian mountains

A multi-institutional team of geoscientists has discovered a deep, ancient underground pool of fresh water underneath part of the Sicilian mountains. In their study, reported in the journal Communications Earth & Environment, the group used publicly available data gathered from oil discovery efforts to study the groundwater in and around the Gela formation beneath the mountains on the island of Sicily.

The researchers analyzed maps and data from prior surveys looking for oil deposits. They discovered what they believe to be a previously unknown aquifer thousands of feet below the Hyblaean Mountains. They made 3D models of the aquifer to validate their findings and found evidence suggesting that not only is it an aquifer, but it holds approximately 17.5 cubic kilometers of water.
The team then set out to explain how so much fresh water could have come to reside, locked in, beneath a mountain range. They suggest it was trapped there during the Messinian salinity crisis millions of years ago—the 700,000-year period saw a blockage at the Strait of Gibraltar that allowed many parts of the Mediterranean Sea to dry up, exposing the seafloor to rainwater.
The research team suggests that this rainwater trickled down into the crust. Such rainwater, the researchers note, could have accumulated underground as it was soaked up by carbonate rock acting as a sponge. When sea levels returned to normal, the underground fresh water was locked in due to seawater pressure.

Lorenzo Lipparini et al, Extensive freshened groundwater resources emplaced during the Messinian sea-level drawdown in southern Sicily, Italy, Communications Earth & Environment (2023). DOI: 10.1038/s43247-023-01077-w

Genetic mutations that promote reproduction tend to shorten human lifespan, study shows

A  study based on a review of genetic and health information from more than 276,000 people finds strong support for a decades-old evolutionary theory that sought to explain aging and senescence.

In 1957, evolutionary biologist George Williams proposed that genetic mutations that contribute to aging could be favored by natural selection if they are advantageous early in life in promoting earlier reproduction or the production of more offspring.

Now known as the antagonistic pleiotropy theory of aging, remains the prevailing evolutionary explanation of senescence, the process of becoming old or aging. 

This theory was tested now. 

The researchers found reproduction and lifespan to be genetically strongly negatively correlated, meaning that genetic mutations that promote reproduction tend to shorten lifespan.

In addition, individuals carrying mutations that predispose them to relatively high reproductive rates have lower probabilities of living to age 76 than those carrying mutations that predispose them to relatively low reproductive rates, according to the study.

However, the authors caution that reproduction and lifespan are affected by both genes and the environment. And compared with environmental factors—including the impacts of contraception and abortion on reproduction and medical advances on lifespan—the genetic factors discussed in the study play a relatively minor role, according to the authors. These results provide strong support for the Williams hypothesis that aging arises as a byproduct of natural selection for earlier and more reproduction. Natural selection cares little about how long we live after the completion of reproduction, because our fitness is largely set by the end of reproduction.

Fitness is a concept biologists use to describe the degree to which an organism's characteristics increase its number of offspring.

The researchers now  found that when you control for the genetically predicted amount and timing of reproduction, having two kids corresponds to the longest lifespan. Having fewer or more kids both lower the lifespan. That result supports the findings of several previous studies.

Part 1

In genetics, the concept of pleiotropy posits that a single mutation can influence multiple traits. The idea that the same mutation can be both beneficial and harmful, depending on the situation, is known as antagonistic pleiotropy and was proposed by Williams to underlie the origin of aging in a paper titled "Pleiotropy, natural selection, and the evolution of senescence."

To a biologist, senescence refers specifically to a gradual decline of bodily functions that manifests as a decline in reproductive performance and an increase in the death rate with age.

Compared with environmental factors, genetic factors play a minor role in the human phenotypic changes studied here.

Erping Long et al, Evidence for the role of selection for reproductively advantageous alleles in human aging, Science Advances (2023). DOI: 10.1126/sciadv.adh4990. www.science.org/doi/10.1126/sciadv.adh4990

Part 2

**

Researchers discover a mechanism that controls the identity of stem cells

Researchers  discovered a mechanism that controls the identity of stem cells. When this mechanism fails, embryonic stem cells revert back in time and become totipotent (totipotent embryo cells can differentiate into a hundred different cell types specialized to form such tissues as skin, marrow, and muscle).

When a cell becomes totipotent, this rare change enables the cells to differentiate into hundreds of cell types, and then go on to form every part of our body. This contrasts with pluripotent stem cells, which can divide into various cell types but are unable to become an entire organism solely on their own.

In a dish of embryonic stem cells, the majority of stem cells are pluripotent. However, 1 out of 1,000 cells are different from the rest, and are totipotent. Totipotent cells are the only cells that have unlimited potential and can give rise to all parts of our body. Scientists now discovered the mechanism that allows this change from pluripotent to totipotent.

Denis Torre et al, Nuclear RNA catabolism controls endogenous retroviruses, gene expression asymmetry, and dedifferentiation, Molecular Cell (2023). DOI: 10.1016/j.molcel.2023.10.036

Credit: Molecular Cell (2023). DOI: 10.1016/j.molcel.2023.10.036

Rich nations need to ditch fossil fuels by 2040: scientists

Rich countries need to stop using coal by 2030 and oil and gas by 2040, with poorer nations following a decade behind, to give the world a chance of limiting warming to 1.5C, climate scientists told the UN this week.

In a note to the UN Secretary-General Antonio Guterres and UN Climate Change body, shared with AFP, climate scientists said there was very little room for anything but a total phase-out of fossil fuels.

The steep timeline they laid out comes as climate negotiators at the COP28 talks in Dubai are tussling over the future of oil, gas and coal, responsible for the lion's share of humanity's planet-heating emissions.

The UN climate negotiations are tasked with helping the world meet the Paris deal goal of limiting global warming to 1.5 degrees Celsius from pre-industrial levels, but have often been vague on how that target will be achieved.

The discussions should be around serious and fair efforts to start implementing a phase out plan: scientists

Source: AFP

---

Israel's AI can produce 100 bombing targets a day in Gaza. Is this ...

Last week, reports emerged that the Israel Defense Forces (IDF) are using an artificial intelligence (AI) system called Habsora (Hebrew for "The Gospel") to select targets in the war on Hamas in Gaza. The system has reportedly been used to find more targets for bombing, to link locations to Hamas operatives, and to estimate likely numbers of civilian deaths in advance.

https://theconversation.com/israels-ai-can-produce-100-bombing-targ...

Catalyst makes drugs inside the body to minimize side effects

A highly active catalyst capable of synthesizing drug molecules within the body has been developed by  chemists. In mice, an anticancer drug assembled near tumors using the injected catalyst suppressed tumour growth.

In conventional medicines delivered by injection or pill, the active drug molecule circulates throughout the body, flooding not only the target site but also healthy tissues. The resulting side effects can be so serious that they can cause permanent damage and force treatment to be stopped. Assembling drug molecules at target sites within the body could make them more effective while minimizing their side effects.

The direct synthesis of drugs in the body would enable drugs to treat diseases without causing side effects in healthy tissues. That's why we need a biocompatible biocatalysis system to perform drug synthesis near target sites in the body.

The team targeted drug assembly in the body using a catalytic chemical reaction called olefin metathesis. Olefin metathesis is one of the most efficient methods for constructing carbon–carbon double bonds for synthesizing drugs. If it could be worked out in the body, it should enable us to synthesize many different types of drugs.

Most chemical catalysts are rapidly deactivated by biomolecules in the bloodstream. To overcome this problem, the team wrapped a ruthenium-based olefin metathesis catalyst inside a protective protein called human serum albumin.

Tanaka's team had previously shown that a ruthenium chloride complex embedded inside human serum albumin—forming a catalytic assembly called an artificial metalloenzyme—was somewhat active in blood. Now, they have shown that switching to a ruthenium iodide complex produces a far superior artificial metalloenzyme.

At low catalyst concentrations, the new albumin-based ruthenium iodide (AlbRuI) catalyst catalyzed three types of olefin metathesis reactions in blood at high yield.

AlbRuI also showed robust stability for 24 hours in blood.This expands the biocompatibility of artificial metalloenzymes and opens the door for developing general, metal-based artificial metalloenzymes for catalytic reactions in blood.

The team also showed that a low dose of cancer-targeting AlbRuI significantly inhibited tumour growth in mice through localized synthesis of an antitumour drug.

 Igor Nasibullin et al, Catalytic olefin metathesis in blood, Chemical Science (2023). DOI: 10.1039/D3SC03785A

‘Tweezers’ hold quantum molecule
Physicists have used lasers as ‘optical tweezers’ to position molecules so precisely that the molecules can be used as qubits to process quantum information. Pairs of calcium monofluoride molecules were gingerly manoeuvred so that they became entangled and behaved as a single collective quantum system. The molecules were cooled to close to absolute zero, making them almost completely still. When their rotation was completely stopped, they represented the ‘0’ state of the qubit. Meanwhile, molecules allowed to rotate with just one quantum of rotational momentum represented the ‘1’ state. Molecules have some advantages over other qubit candidates, such as atoms. For example, molecules could be pushed into service as ‘qutrits’, which have three possible states: −1, 0 and +1.

https://www.science.org/doi/10.1126/science.adf8999

https://www.science.org/doi/10.1126/science.adf4272

The Climate Change We've Already Created Will Last 50,000 Years, Scientists Warn

The idea of an entirely new and human-created geological epoch is a sobering scenario as context for the current UN climate summit, COP28. The impact of decisions made at these and other similar conferences will be felt not just beyond our own lives and those of our children, but perhaps beyond the life of human society as we know it.

Enormous deforestation, the mushrooming of dams across the world's large rivers, overfishing, a planet's nitrogen cycle overwhelmed by fertiliser use, the rapid rise in greenhouse gases.....

As for climate change itself, well, the warning bells were ringing, certainly. Global mean surface temperatures had risen by about half a degree since the mid-20th century. But, they were still within the norm for an interglacial phase of the ice ages. Among many emerging problems, climate seemed one for the future.

A little more than two decades on, the future has arrived. By 2022, global temperature had climbed another half a degree, the past nine years being the hottest since records began. And 2023 has seen climate records being not just broken, but smashed.

With this leap in temperatures came record-breaking heatwaves, wildfires and floods, exacerbated by other local human actions. Climate has moved centre stage on an Anthropocene Earth.

To see how this might play out on a geological timescale, we need to look through the lens of the Anthropocene. A delicately balanced planetary machinery of regular, multi-millennial variations in the Earth's spin and orbit has tightly controlled patterns of warm and cold for millions of years.

Now, suddenly, this control machinery has been overridden by a trillion tons of carbon dioxide injected into the atmosphere in little more than a century.

Part 1

Modelling the effects of this pulse through the Earth System shows that this new, suddenly disrupted, climate pattern is here for at least 50,000 years and probably far longer. It's a large part of the way our planet has changed fundamentally and irreversibly, to become comparable to some of the great climate change events in deep Earth history.

So will this particular COP meeting, with fossil fuel interests so strongly represented, make a difference? The bottom line is that attaining, and stabilising carbon emissions at "net zero" is only a crucial first step.

This latest warming step has already taken the Earth into levels of climate warmth not experienced for some 120,000 years, into those of the last interglacial phase, a little warmer than the current one. There is yet more warming in the pipeline over coming centuries, as various feedbacks take effect. A recent study on the effects of this warming on Antarctica's ice suggests that "policymakers should be prepared for several metres of sea-level rise over the coming centuries" as the pulse of warmth spreads through the oceans to undermine the great polar ice-sheets.

https://theconversation.com/the-climate-change-we-caused-is-here-fo...

Part 2

Biocrusts on Great Wall of China found to be protecting it from erosion

A small international team of soil and water ecosystem conservation specialists has found that biocrusts clinging to parts of the Great Wall of China have been serving to protect the famous structure from erosion. In their paper published in the journal Science Advances (1), the group describes their study and analysis of material growing on the wall.

The Great Wall of China was built over several centuries starting approximately 221 BC—its function was to protect the people living behind it from enemies attempting to invade from the other side. Prior research has shown that different parts of the wall were made with different materials—mostly rammed earth or stone.

Rammed earth is made by mixing organic materials with inorganic materials. Because of their nature, such materials are more susceptible to erosion. That has led to questions regarding how sections of the wall made with the material have survived for so many years. In this new effort, the researchers wondered if perhaps biocrusts may have played a role.

For many years, scientists have assumed that such biocrusts, which are generally made of cyanobacteria, lichen and mosses, speed up the erosion process. To find out if that is the case, the research team collected samples of the biocrusts from several points along the wall and brought them back to a lab for study.

The researchers measured the mechanical strength and soil stability of the samples. They also tested parts of the wall directly comparing those covered in biocrusts and those that were directly exposed to the elements.

They found that the biocrusts were stronger than the rammed earth material upon which they were growing—in some cases, three times as strong. The researchers also found the strength in the biocrusts was due to secretion of tightly bound polymers.

The research team concluded that rather than speeding up erosion, the biocrusts have been slowing the process, helping to preserve the famed structure. Somewhat analogous to their findings were those by a team from the University of Granada working in Honduras that found that organic plant materials added to plasters by early Mayan people have served to reduce weathering of the stone structures they built(2). 

Footnotes:

1.Yousong Cao et al, Biocrusts protect the Great Wall of China from erosion, Science Advances (2023). DOI: 10.1126/sciadv.adk5892

2. Carlos Rodriguez-Navarro et al, Unveiling the secret of ancient Maya masons: Biomimetic lime plasters with plant extracts, Science Advances (2023). DOI: 10.1126/sciadv.adf6138

Phenomena called 'Steve' and 'picket fence' are masquerading as auroras

The shimmering green, red and purple curtains of the northern and southern lights—the auroras—may be the best-known phenomena lighting up the nighttime sky, but the most mysterious are the mauve and white streaks called Steve and their frequent companion, a glowing green "picket fence."

First recognized in 2018 as distinct from the common auroras, Steve and its associated picket fence were nevertheless thought to be caused by the same physical processes. But scientists were left scratching their heads about how these glowing emissions were produced.

Vibrant auroras and glowing phenomena such as Steve and the picket fence are becoming more common as the sun enters the active period of its 11-year cycle.

Because all these transient luminous phenomena are triggered by solar storms and coronal mass ejections from the sun, the approaching solar maximum is an ideal time to study rare events like Steve and the picket fence.

In a region of the upper atmosphere farther south than that in which auroras form, electric fields parallel to Earth's magnetic field could produce the color spectrum of the picket fence. If correct, this unusual process has implications for how physicists understand energy flow between Earth's magnetosphere, which surrounds and protects Earth from the solar wind, and the ionosphere at the edge of space.

A new  paper  showed that parallel electric fields are capable of explaining this exotic spectrum.

Part 1

The common auroras are produced when the solar wind energizes particles in Earth's magnetosphere, often at altitudes higher than 1,000 kilometers above the surface. These energized particles spiral around Earth's magnetic field lines toward the poles, where they crash into and excite oxygen and nitrogen molecules in the upper atmosphere. When those molecules relax, oxygen emits specific frequencies of green and red light, while nitrogen generates a bit of red, but primarily a blue, emission line.

The colorful, shimmering curtains that result can extend for thousands of kilometers across the northern or southern latitudes.

Steve, however, displays not individual emission lines, but a broad range of frequencies centered around purple or mauve. And unlike auroras, neither Steve nor the picket fence emit blue light, which is generated when the most energetic particles hit and ionize nitrogen. Steve and the picket fence also occur at lower latitudes than the aurora, potentially even as far south as the equator.

Some researchers proposed that Steve is caused by ion flows in the upper atmosphere, referred to as subauroral ion drift, or SAID, though there's no well accepted physical explanation for how SAID could generate the colorful emissions.

There are also other suggestions that the picket fence's emissions could be generated by low-altitude electric fields parallel to Earth's magnetic field, a situation thought to be impossible because any electric field aligned with the magnetic field should quickly short out and disappear.

One model showed that a moderate parallel electric field—around 100 millivolts per meter—at a height of about 110 km could accelerate electrons to an energy that would excite oxygen and nitrogen and generate the spectrum of light observed from the picket fence. Unusual conditions in that area, such as a lower density of charged plasma and more neutral atoms of oxygen and nitrogen, could potentially act as insulation to keep the electric field from shorting out.

If you look at the spectrum of the picket fence, it's much more green than you would expect. And there's none of the blue that's coming from the ionization of nitrogen. What that's telling us is that there's only a specific energy range of electrons that can create those colors, and they can't be coming from way out in space down into the atmosphere, because those particles have too much energy.

Instead the light from the picket fence is being created by particles that have to be energized right there in space by a parallel electric field, which is a completely different mechanism than any of the aurora that researchers have studied or known before.

They also suspect that Steve itself may be produced by related processes. Their calculations also predict the type of ultraviolet emissions that this process would produce, which can be checked to verify the new hypothesis about the picket fence.

Though some calculations don't directly address the on-off glow that makes the phenomenon look like a picket fence, it's likely due to wavelike variations in the electric field. And while the particles that are accelerated by the electric field are probably not from the sun, the scrambling of the atmosphere by solar storms  probably triggers Steve and the picket fence, as it does the common aurora.

Part 2

Scientists are trying to test this now . They are trying to   launch a rocket from Alaska through these phenomena and measure the strength and direction of the electric and magnetic fields. SSL scientists specialize in designing and building instruments that do just that. Many of these instruments are on spacecraft now orbiting Earth and the sun.

Initially, the target would be what's known as an enhanced aurora, which is a normal aurora with picket fence-like emissions embedded in it.

The enhanced aurora is basically this bright layer that's embedded in the normal aurora. The colors are similar to the picket fence in that there's not as much blue in them, and there's more green from oxygen and red from nitrogen. The hypothesis is that these are also created by parallel electric fields, but they are a lot more common than the picket fence.

The plan is not only to fly a rocket through that enhanced layer to actually measure those parallel electric fields for the first time but also to distinguish the conditions from those that cause the auroras. Eventually, researchers hope  for a rocket that will fly directly through Steve and the picket fence.

 L. Claire Gasque et al, It's Not Easy Being Green: Kinetic Modeling of the Emission Spectrum Observed in STEVE's Picket Fence, Geophysical Research Letters (2023). DOI: 10.1029/2023GL106073

Part 3

**

Corrosion at atomic level

The cost of repairing corrosion worldwide is estimated at $2.5 trillion a year, which is more than 3% of the global GDP—so developing better ways to manage oxidation would be an economic boon.

When water vapor meets metal, the resulting corrosion can lead to mechanical problems that harm a machine's performance. Through a process called passivation, it also can form a thin inert layer that acts as a barrier against further deterioration.

A technique called environmental transmission electron microscopy (TEM),  allows researchers to directly view molecules interacting on the tiniest possible scale.

Researchers  introduced water vapour to clean aluminum samples and observed the surface reactions. They discovered something that had never been observed before: In addition to the aluminum hydroxide layer that formed on the surface, a second amorphous layer developed underneath it, which indicates there is a transport mechanism that diffuses oxygen into the substrate.

Understanding how a water molecule's hydrogen and oxygen atoms break apart to interact with metals could lead to clean-energy solutions.

Xiaobo Chen et al, Atomistic mechanisms of water vapor–induced surface passivation, Science Advances (2023). DOI: 10.1126/sciadv.adh5565