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Comment by Dr. Krishna Kumari Challa on August 25, 2022 at 12:36pm

New research on the risks of lead exposure from bullets used in big game hunting

The lead in some bullets used for hunting deer, moose, and elk is toxic to the humans who eat the harvested meat and to scavenger animals that feast on remains left in the field.

Comment by Dr. Krishna Kumari Challa on August 25, 2022 at 9:56am

Here's what a black hole sounds like, according to NASA.

Data Sonification: Black Hole at the Center of the Perseus Galaxy Cluster (X-ray)

Comment by Dr. Krishna Kumari Challa on August 25, 2022 at 9:44am

Experiment on YouTube reveals potential to 'inoculate' users against misinformation

Fact-checkers can only rebut a fraction of the falsehoods circulating online. We need to teach people to recognize the misinformation playbook, so they understand when they are being misled.

https://phys.org/news/2022-08-youtube-reveals-potential-inoculate-m...

Comment by Dr. Krishna Kumari Challa on August 24, 2022 at 12:01pm

Study shows 90% of marine species at risk of extinction by 2100 if greenhouse gas emissions are not curbed

An international team of researchers has found that approximately 90% of all marine life on Earth will be at risk of extinction by 2100 if greenhouse gas emissions are not curbed. In their paper published in the journal Nature Climate Change, the group outlines their study of thousands of marine species and how greenhouse gas emissions might impact them in the future.

Greenhouse gas emissions impact the world's climate in two ways. They raise the temperature of the atmosphere (and by extension, Earth's surfaces and bodies of water) by holding in heat, and in the case of CO₂ emissions, they make water more acidic, like carbonated soft drinks. And as emissions continue to be pumped into the atmosphere despite dire warnings from scientists around the world, more research is being conducted to learn about its possible impact. In this new effort, the researchers took a broad look at the impact of greenhouse gas emissions on ocean life.

The work involved estimating the impact of certain levels of greenhouse gas emissions on marine life in the future. They looked specifically at 25,000 species, including fish, bacteria, plants and protozoans living in the top 100 meters of the world's oceans. They found that under the worst scenario, in which emissions lead to global atmospheric temperature increases of 3 to 5 degrees Celsius, approximately 90% of all marine life will disappear. They also found that if emissions are cut to the extent outlined by the Paris Climate Agreement, which would keep global temperature increases to below 2 degrees Celsius, then the risk of extinction would be reduced by approximately 98%.

The researchers also found that larger top predators are more at risk than smaller predators, as are fish species  in areas where they are heavily fished by humans. Those at lowest risk, on the other hand, include small, short-lived species. Notably, Earth has not seen a die-off as great as these projections since the Great Dying 252 million years ago.

Daniel G. Boyce et al, A climate risk index for marine life, Nature Climate Change (2022). DOI: 10.1038/s41558-022-01437-y

Comment by Dr. Krishna Kumari Challa on August 24, 2022 at 11:58am

Your Next Wooden Chair Could Arrive Flat, Then Dry Into a 3D Shape

Comment by Dr. Krishna Kumari Challa on August 23, 2022 at 8:23am

Researchers discover a material that can learn like the brain

Researchers have discovered that Vanadium Dioxide (VO₂), a compound used in electronics, is capable of "remembering" the entire history of previous external stimuli. This is the first material to be identified as possessing this property, although there could be others.

A PhD student made a chance discovery during his research on phase transitions in Vanadium Dioxide (VO₂). VO₂ has an insulating phase when relaxed at room temperature, and undergoes a steep insulator-to-metal transition at 68 °C, where its lattice structure changes. Classically, VO₂ exhibits a volatile memory: "the material reverts back to the insulating state right after removing the excitation" . For his thesis, he set out to discover how long it takes for VO₂ to transition from one state to another. But his research led him down a different path: after taking hundreds of measurements, he observed a memory effect in the material's structure.

In his experiments, the student applied an electric current  to a sample of VO₂. The current moved across the material, following a path until it exited on the other side. As the current heated up the sample, it caused the VO₂ to change state. And once the current had passed, the material returned to its initial state.

He then applied a second current pulse to the material, and saw that the time it took to change state was directly linked to the history of the material. The VO₂ seemed to 'remember' the first phase transition and anticipate the next. The researchers didn't expect to see this kind of memory effect, and it has nothing to do with electronic states but rather with the physical structure of the material. It's a novel discovery: no other material behaves in this way.

The researchers went on to find that VO₂ is capable of remembering its most recent external stimulus for up to three hours. The memory effect could in fact persist for several days, but we don't currently have the instruments needed to measure that.

The research team's discovery is important because the memory effect they observed is an innate property of the material itself. Engineers rely on memory to perform calculations of all kinds, and materials that could enhance the calculation process by offering greater capacity, speed and miniaturization are in high demand. VO₂ ticks all three of these boxes. What's more, its continuous, structural memory sets it apart from conventional materials that store data as binary information dependent on the manipulation of electronic states.

The researchers performed a host of measurements to arrive at their findings. They also corroborated their results by applying the new method to different materials at other laboratories around the world. This discovery replicates well what happens in the brain, as VO₂ switches act just like neurons.

Mohammad Samizadeh Nikoo, Electrical control of glass-like dynamics in vanadium dioxide for data storage and processing, Nature Electronics (2022). DOI: 10.1038/s41928-022-00812-z. www.nature.com/articles/s41928-022-00812-z

Comment by Dr. Krishna Kumari Challa on August 22, 2022 at 10:13am

How Quinine Fights Malaria

Comment by Dr. Krishna Kumari Challa on August 20, 2022 at 10:14am

Non-nutritive sweeteners affect human microbiomes and can alter glycemic responses

Since the late 1800s non-nutritive sweeteners have promised to deliver all the sweetness of sugar with none of the calories. They have long been believed to have no effect on the human body, but researchers publishing in the journal Cell on August 19 challenge this notion by finding that these sugar substitutes are not inert, and, in fact, some can alter human consumers' microbiomes in a way that can change their blood sugar levels.

In 2014 researchers found that non-nutritive sweeteners affected the microbiomes of mice in ways that could impact their glycemic responses. They were interested in whether these results would also be found in humans.

To address this important question, the researchers  carefully screened over 1,300 individuals for those who strictly avoid non-nutritive sweeteners in their day-to-day lives, and identified a cohort of 120 individuals. These participants were broken into six groups: two controls and four who ingested well below the FDA daily allowances of either aspartame, saccharin, stevia, or sucralose.

In subjects consuming the non-nutritive sweeteners, scientists could identify very distinct changes in the composition and function of gut microbes, and the molecules they secret into peripheral blood. This seemed to suggest that gut microbes in the human body are rather responsive to each of these sweeteners.

When they looked at consumers of non-nutritive sweeteners as groups, they found that two of the non-nutritive sweeteners, saccharin and sucralose, significantly impacted glucose tolerance in healthy adults. Interestingly, changes in the microbes were highly correlated with the alterations noted in people's glycemic responses.

To establish causation, the researchers transferred microbial samples from the study subjects to germ-free mice—mice that have been raised in completely sterile conditions and have no microbiome of their own.

The results were quite striking. In all of the non-nutritive sweetener groups, but in none of the controls, when the researchers transferred into these sterile mice the microbiome of the top responder individuals collected at a time point in which they were consuming the respective non-nutritive sweeteners, the recipient mice developed glycemic alterations that very significantly mirrored those of the donor individuals. In contrast, the bottom responders' microbiomes were mostly unable to elicit such glycemic responses. These results suggest that the microbiome changes in response to human consumption of non-nutritive sweetener may, at times, induce glycemic changes in consumers in a highly personalized manner.

The effects of the sweeteners will vary person to person because of the incredibly unique composition of our microbiome.

 Eran Elinav, Personalized microbiome-driven effects of non-nutritive sweeteners on human glucose tolerance, Cell (2022). DOI: 10.1016/j.cell.2022.07.016. www.cell.com/cell/fulltext/S0092-8674(22)00919-9

Comment by Dr. Krishna Kumari Challa on August 20, 2022 at 8:19am

How the brain gathers threat cues and turns them into fear

Scientists have uncovered a molecular pathway that distills threatening sights, sounds and smells into a single message: Be afraid. A molecule called CGRP enables neurons in two separate areas of the brain to bundle threatening sensory cues into a unified signal, tag it as negative and convey it to the amygdala, which translates the signal into fear.

The research, published in Cell Reports on August 16, 2022, may lead to new therapies for fear-related disorders such as post-traumatic stress disorder (PTSD) or hypersensitivity disorders such as autism, migraines and fibromyalgia.

The brain pathway researchers now discovered works like a central alarm system. The CGRP neurons are activated by negative sensory cues from all five senses—sight, sound, taste, smell and touch. Identifying new threat pathways provides insights into treating fear-related disorders.

Most external threats involve multisensory cues, such as the heat, smoke and smell of a wildfire. Previous research showed that different pathways independently relay sound, sight, and touch threat cues to multiple brain areas. A single pathway that integrates all these cues would be beneficial to survival, but no one had ever found such a pathway.

Previous research also showed that the amygdala, which initiates behavioral responses and forms fear memories to environmental and emotional stimuli, receives heavy input from brain regions that are laden with a chemical associated with aversion, the neuropeptide CGRP (calcitonin gene-related peptide).

Based on these two pools of research,  researchers now proposed that CGRP neurons, found especially in subregions of the thalamus and the brainstem, relay multisensory threat information to the amygdala. These circuits may both generate appropriate behavioral responses and help form aversive memories of threat cues.

The researchers conducted several experiments to test their hypotheses. They recorded CGRP neuron activity using single-cell calcium imaging while presenting mice with multisensory threat cues, enabling the researchers to pinpoint which sensory modality involved which sets of neurons. They determined the path the signals took after leaving the thalamus and brainstem using different colored fluorescent proteins. And they conducted behavioral tests to gauge memory and fear.

Taken together, their findings show that two distinct populations of CGRP neurons—one in the thalamus, one in the brainstem—project to nonoverlapping areas of the amygdala, forming two distinct circuits. Both populations encode threatening sights, sounds, smells, tastes and touches by communicating with local brain networks. Finally, they discovered that both circuits are necessary for forming aversive memories—the kind that tell you, "Stay away."

While mice were used in this study, the same brain regions also abundantly express CGRP in humans. This suggests that the circuits reported here may also be involved in threat perception-related psychiatric disorders.

https://www.cell.com/cell-reports/fulltext/S2211-1247(22)01039-7?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2211124722010397%3Fshowall%3Dtrue

Comment by Dr. Krishna Kumari Challa on August 20, 2022 at 7:45am

Can a human with a spinal cord injury walk and run? Discovering clues with neuromorphic technology

 An international research team  has succeeded in recovering muscle movements in a model of paralyzed mice through organic artificial nerves. The result was published in Nature Biomedical Engineering.

The nerves, which are essential for life activities as well as having a significant impact on quality of life, are easily damaged by various causes such as physical injury, genetic causes, secondary complications, and aging. In addition, once nerves are damaged they are difficult to reconstruct, and some or all their bodily functions are permanently lost due to poor bio-signaling.

Among the various methods for rehabilitation in patients with neurological damage, Functional Electrical Stimulation (FES), which is currently actively used in clinical practice, uses computer-controlled signals. Through this setup, electrical stimulation is applied to muscles that are no longer arbitrarily controllable in patients with neuropathy to induce muscle contraction, resulting in functionally useful movements in the biological body even though they are confined in a specific space. However, this conventional approach has limitations that are not suitable for long-term use in patients' daily lives because they involve complex digital circuits and computers for signal processing to stimulate muscles, consuming a lot of energy and poor biocompatibility in the process.

To solve the problem, the research team succeeded in controlling the leg movement of mice only with artificial nerves without a complex and bulky external computer using stretchable, low-power organic nanowire neurormorphic devices that emulate the structure and function of bio nerve fibers. The stretchable artificial nerve consists of a strain sensor that simulates a proprioceptor which detects muscle movements, an organic artificial synapse that simulates a biological synapse, and a hydrogel electrode for transmitting signals to the leg muscles.

The researchers adjusted the movement of the mouse legs and the contraction force of the muscles according to the firing frequency of the action potential transmitted to the artificial synapse with a principle similar to that of the biological nerve, and the artificial synapse implements smoother and more natural leg movements than the usual FES.

In addition, the artificial proprioceptor detects the leg movement of the mouse and gives real-time feedback to the artificial synapse to prevent muscle damage due to excessive leg movement.

The researchers succeeded in allowing a paralyzed mouse to kick the ball or walk and run on the treadmill. Furthermore, the research team showed the applicability of artificial nerves in the future for voluntary movement by sampling pre-recorded signals from the motor cortexes of moving animals and moved the legs of mice through artificial synapses.

The researchers discovered a new application feasibility in the field of neuromorphic technology, which is attracting attention as a next-generation computing device by emulating the behavior of a biological neural network.

https://www.nature.com/articles/s41551-022-00918-x

https://www.eurekalert.org/news-releases/961673

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