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Comment by Dr. Krishna Kumari Challa on June 5, 2024 at 12:29pm

Nocturnal heat exposure and stroke risk

Hot Nights Linked With Increased Risk of Stroke, Scientists Warn

The risk of suffering a stroke is significantly higher with high overnight temperatures, posing a potential health concern around the globe as the world gets warmer.

Mapping night-time temperatures against the number of stroke cases recorded in the German city of Augsburg across the course of 15 years, a research team found a statistically significant increase in stroke risk on days where extremely warm night-time temperatures were recorded, with older people and women particularly vulnerable.

Overall, the risk of stroke increased by 7 percent during nights categorized as "tropical". For the purposes of this research, a tropical night was one where the temperature remained above 14.6 °C (58.3 °F). These nights represented the hottest 5 percent of nights across the course of the study period.

There was evidence of a higher number of stroke incidents over time, too: from 2006 to 2012, hot nights were linked to two additional strokes per year, whereas from 2013 to 2020, hot nights were associated with 33 additional cases per year. That reflects increasing temperatures as the years went by.

The researchers say a variety of factors could be behind the statistics, including a greater chance of dehydration – already known to increase the likelihood of suffering a stroke. Limited access to technology such as air conditioning could also play a part.

https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurh...

"In summary, changes in underlying drivers from climatic factors, stroke risk factors, and socioeconomic conditions may contribute to the increased susceptibility to night-time heat-related stroke over time," write the researchers in their published paper.

Comment by Dr. Krishna Kumari Challa on June 5, 2024 at 11:38am

Relative entropy, which requires two states, in this case, corresponds to the universe and its partner anti-universe. Accelerated expansion seems inevitable in a universe created in pairs that respect the null energy condition. This result is quite surprising and readers familiar with Hawking's area theorem may notice some similarities. The area theorem also deals with causal horizons and requires the null energy condition to hold.

In this new model, the causal horizon corresponds to the Big Bang. The results apply equally to the partner anti-universe.

 Naman Kumar, On the Accelerated Expansion of the Universe, Gravitation and Cosmology (2024). DOI: 10.1134/S0202289324010080

Part 2

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Comment by Dr. Krishna Kumari Challa on June 5, 2024 at 11:36am

New model suggests partner anti-universe could explain accelerated expansion without the need for dark energy

The accelerated expansion of the present universe, believed to be driven by a mysterious dark energy, is one of the greatest puzzles in our understanding of the cosmos. The standard model of cosmology called Lambda-CDM, explains this expansion as a cosmological constant in Einstein's field equations. However, the cosmological constant itself lacks a complete theoretical understanding, particularly regarding its very small positive value.

To explain the accelerated expansion, physicists have proposed alternative explanations such as quintessence and modified gravity theories, including scalar-tensor-vector gravity. Additionally, explanations beyond four dimensions, like the braneworld scenarios in the Dvali-Gabadadze-Porrati (DGP) model, modify gravity at large distances due to the effect of a higher-dimensional bulk on our four-dimensional brane, and variable brane tension.

Some researchers are now proposing another model to explain the present accelerated expansion of the universe. Unlike existing models, this does not require any form of dark energy or modified gravity approaches. However, there is a price to pay: we need a partner anti-universe whose time flow is oppositely related to our universe.

There are strong arguments supporting this concept. From a quantum theory perspective, it is natural for the universe to be created in pairs. Recently, Boyle et al proposed that the universe does not spontaneously violate CPT (Charge, Parity, and Time reversal symmetry), but rather, the universe after the Big Bang is the CPT image of the universe before it, pointing towards a partner anti-universe.

In a recent paper published in Gravitation and Cosmology, researchers used key concepts from quantum theory, such as relative entropy, and from general relativity, such as the null energy condition, which corresponds to the positive energy condition. The findings suggest that the universe naturally expands in an accelerated manner.

Part 1

Comment by Dr. Krishna Kumari Challa on June 5, 2024 at 11:30am

Commonly used alcohol-based mouthwash brand may disrupt the balance of your oral microbiome, scientists say

The oral microbiome is the community of bacteria that live in the mouth. It helps us digest our food and keep our mouth healthy. Changes to the composition of the oral microbiome have been linked to periodontal diseases and some cancers.

New research, published in Journal of Medical Microbiology is a follow-up to a larger study investigating the use of mouthwash as a method to reduce the transmission of sexually transmitted diseases in men who have sex with men. Researchers wanted to explore further and investigate whether the mouthwash used had an impact on the oral microbiome of the patients.

Researchers found that two species of opportunistic bacteria were significantly more abundant in the mouth after three months of daily use of the alcohol-based mouthwash, Fusobacterium nucleatum and Streptococcus anginosus. These two bacteria have been previously linked to gum disease, esophageal and colorectal cancers. Researchers also saw a decrease in a group of bacteria called Actinobacteria, which are crucial contributors to the regulation of blood pressure.

Alcohol-based mouthwashes are widely available. The public may use them daily to tackle bad breath or prevent periodontitis, but they should be aware of the potential implications.

The effect of daily usage of Listerine Cool Mint mouthwash on the oropharyngeal microbiome: a substudy of the PReGo trial, Journal of Medical Microbiology (2024). DOI: 10.1099/jmm.0.001830

Comment by Dr. Krishna Kumari Challa on June 5, 2024 at 11:25am

Study finds maternal obesity in mice increases microRNA levels in the hypothalamus in offspring, leading to overeating

Maternal obesity impacts the eating behaviours of offspring via long-term overexpression of the microRNA miR-505-5p, according to a study publishing June 4 in the open-access journal PLOS Biology.

 Previous studies in both humans and animal models have shown that the offspring of obese mothers have a higher risk of obesity and type 2 diabetes. While this relationship is likely the result of a complex relationship between genetics and environment, emerging evidence has implicated that maternal obesity can disrupt the hypothalamus—the region of the brain responsible for nutrition sensing and energy homeostasis.

In animal models, offspring exposed to overnutrition during key periods of development eat more, but little is known about the molecular mechanisms that lead to these changes in eating behaviour.

In this new study, researchers found that mice born from obese mothers had higher levels of the microRNA miR-505-5p in their hypothalamus—from as early as the fetal stage into adulthood. The researchers found that the mice ate more and showed a preference for high-fat foods. Interestingly, the effect of maternal obesity on miR-505-5p and eating behaviours was mitigated if the mothers exercised during pregnancy.

Cell culture experiments showed that miR-505-5p expression could be induced by exposing hypothalamic neurons to long-chain fatty acids and insulin, which are both high in pregnancies complicated by obesity. The researchers identified miR-505-5p as a novel regulator of pathways involved in fatty acid uptake and metabolism, therefore, high levels of the miRNA make the offspring brain unable to sense when eating high fat foods.

Several of the genes that miR-505-5p regulates have been associated with high body mass index in human genetic studies. The study is one of the first to demonstrate the molecular mechanism linking nutritional exposure in utero to eating behaviour.

This research work helps us understand why the children of mothers living with obesity are more likely to become obese themselves, with early life exposures, genetics and current environment all being contributing factors.

Dearden L, Furigo IC, Pantaleão LC, Wong LWP, Fernandez-Twinn DS, de Almeida-Faria J, et al. Maternal obesity increases hypothalamic miR-505-5p expression in mouse offspring leading to altered fatty acid sensing and increased intake of high-fat food. PLoS Biology (2024). DOI: 10.1371/journal.pbio.3002641

Comment by Dr. Krishna Kumari Challa on June 5, 2024 at 11:05am

Some countries could meet their total electricity needs from floating solar panels, research shows

Floating solar photovoltaic panels could supply all the electricity needs of some countries, new research has shown.

The study 's aimed to calculate the global potential for deploying low-carbon floating solar arrays. The researchers calculated the daily electrical output for floating photovoltaics (FPVs) on nearly 68,000 lakes and reservoirs around the world, using available climate data for each location.

The researchers' calculations included lakes and reservoirs where floating solar technology is most likely to be installed. They were no more than 10km from a population center, not in a protected area, didn't dry up and didn't freeze for more than six months each year. The researchers calculated output based on FPVs covering just 10% of their surface area, up to a maximum of 30 km².

While output fluctuated depending on altitude, latitude and season, the potential annual electricity generation from FPVs on these lakes was 1,302 terawatt hours (TWh), around four times the total annual electricity demand of the UK.

FPVs have a number of additional advantages over land-based solar installations: they free up land for other uses and they keep panels cooler, making them more efficient.

There is some evidence for other environmental benefits, including reducing water loss through evaporation, by sheltering the lake surface from the sun and wind; and reducing algal blooms by limiting light and preventing nutrient circulation.

However, the researchers point out that we still don't know exactly how floating panels might affect the ecosystem within a natural lake, in different conditions and locations. But the potential gain in energy generation from FPVs is clear, so we need to put that research in place so this technology can be safely adopted. 

 Decarbonisation potential of floating solar photovoltaics on lakes worldwide, Nature Water (2024). DOI: 10.1038/s44221-024-00251-4. www.nature.com/articles/s44221-024-00251-4

Comment by Dr. Krishna Kumari Challa on June 5, 2024 at 10:29am

Researchers identify first step in allergic reactions, paving the way for preventative strategies

Scientists  have identified how the first domino falls after a person encounters an allergen, such as peanuts, shellfish, pollen or dust mites. Their discovery, published in the journal Nature Immunology, could herald the development of drugs to prevent these severe reactions.

It is well established that when mast cells, a type of immune cell, mistake a harmless substance, such as peanuts or dust mites, as a threat, they release an immediate first wave of bioactive chemicals against the perceived threat. When mast cells, which reside under the skin, around blood vessels and in the linings of the airways and the gastrointestinal tract, simultaneously release their pre-stored load of bioactive chemicals into the blood, instant and systemic shock can result, which can be lethal without quick intervention.

More than 10% of the global population suffers from food allergies, according to the World Health Organization (WHO). As allergy rates continue to climb, so does the incidence of food-triggered anaphylaxis and asthma worldwide.

What the researchers have now discovered is that the release of particulate mast cell granules, which contain these bioactive chemicals, is controlled by two members of an intracellular multiprotein complex called inflammasome. Until now, these inflammasome proteins were only known to spontaneously assemble within immune cells to secrete soluble chemicals to alert other parts of the immune system upon detection of an infection.

They discovered that the inflammasome components played a surprisingly crucial role in transporting particulate mast cell granules which are typically packed in the cell center to the cell surface where they are released. This surprising discovery gives us a precise target where we can intervene to prevent the cascade of events initiated in mast cells that leads to anaphylactic shock.

Andrea Mencarelli et al, Anaphylactic degranulation by mast cells requires the mobilization of inflammasome components, Nature Immunology (2024). DOI: 10.1038/s41590-024-01788-y

Comment by Dr. Krishna Kumari Challa on June 5, 2024 at 10:22am

Doctors develop minimally invasive procedure to avoid drilling a 'burr hole' in the skull to treat clot on the brain

In 2018, a New York surgeon-scientist and his team demonstrated in a proof-of-concept study that a minimally invasive procedure could effectively treat one of the world's most common conditions requiring neurosurgical intervention.

The condition is called chronic subdural hematoma, an accumulation of blood and blood breakdown products on the brain's surface just beneath the dura, the brain's protective covering. The mass is caused by damaged vessels that chronically leak blood between the brain and the dura. Risk factors for the abnormality, which can reach significant size, include older age; untreated head trauma; long-term use of blood thinning agents, such as warfarin, or extensive time on anti-inflammatory drugs, like ibuprofen.

Now doctors at Stony Brook Medicine report that not only is the new method of alleviating chronic subdural hematoma effective, it's destined to replace the invasive old-school surgery to remove the accumulation of blood.

The new method of treatment is called middle meningeal artery embolization—MMAE—which relies on an injectable fluid to plug the leakage. Studies conducted around the world show that it's safe, effective and eliminates the risks of surgery. Research at Stony Brook led to a global study of the procedure, and doctors have now demonstrated that the new method not only stops the leakage, it forces the hematoma into permanent retreat.

The standard of care for decades has been surgery, which was designed to provide drainage by drilling a burr hole into the skull or performing a craniotomy, the surgical removal of a portion of the skull to release accumulated blood. While these procedures can alleviate the mass, a chronic subdural hematoma can recur despite the highly invasive attempt to eliminate it. The recurrence rate runs as high as 20%, studies have shown.

Worse, surgery is often poorly tolerated by a broad population of patients.

Chronic subdural hematoma as an insidious condition, developing slowly, often over weeks to months. The mass can put pressure on the brain causing a range of symptoms: slurred speech, forgetfulness, impaired motor function, even coma.

The new approach uses a specialized fluid that is injected into the middle meningeal arteries through a micro-catheter. The liquid embolic agent blocks—embolizes—the abnormal blood vessels that are responsible for the chronic leakage of blood onto the brain's surface. The liquid embolic agent solidifies once it enters the vasculature. Doctors view each step of the procedure via imaging technology.

The enormous potential of a minimally invasive procedure that is safe and effective has captured the attention of neurosurgeons around the world.

David Fiorella et al, Middle meningeal artery embolization for the management of chronic subdural hematoma: what a difference a few years make, Journal of NeuroInterventional Surgery (2023). DOI: 10.1136/jnis-2023-020498

Arindam Rano Chatterjee, Invited Commentary: A New Era in the Treatment of Chronic Subdural Hematomas, RadioGraphics (2024). DOI: 10.1148/rg.240038

Comment by Dr. Krishna Kumari Challa on June 4, 2024 at 10:41am

Greener, more effective termite control: Natural compound attracts wood eaters

Scientists have discovered a highly effective, nontoxic, and less expensive way to lure hungry termites to their doom.

The method, detailed in the Journal of Economic Entomology, uses a pleasant-smelling chemical released by forest trees called pinene that reminds western drywood termites of their food. They follow the scent to a spot of insecticide injected into wood.

Researchers saw significant differences in the death rates using insecticide alone versus the insecticide plus pinene. Without pinene, they got about 70% mortality. When they added it in, it was over 95%.

Fumigation is one of the most common drywood termite control techniques. Homes are covered with tents and then bombed with gas that kills the insects.

The pest control industry is under pressure to find new methods because the chemical, sulfuryl fluoride, is both a greenhouse gas and is also toxic to humans. Additionally, fumigation is an expensive process that does not provide lasting protection against termites.

Even though it is very thorough, a home can be infested again soon after fumigation is completed. Some people fumigate every three to five years because it doesn't protect structures from future infestations.

Localized injection is an alternative strategy to control drywood termites that does not involve gas. Technicians drill holes into the infested wood to reach the termite "gallery" or lair, then inject poison into the hole to inundate the bugs.

This is a more localized treatment, and in theory, it is a better strategy when you want to control drywood termites with fewer chemicals. It's less expensive, and the treated wood may also stay protected from future infestations.

The challenge with localized injection is figuring out exactly where the bugs are hiding. Typically, this method uses a contact-based insecticide, meaning the insects must touch the poison for it to work.

Using an attractant like pinene eliminates the need to hunt for the termites. Even at low concentrations, pinene is good at attracting termites from a distance.

 Nicholas A Poulos et al, Potential use of pinenes to improve localized insecticide injections targeting the western drywood termite (Blattodea: Kalotermitidae), Journal of Economic Entomology (2024). DOI: 10.1093/jee/toae101

Comment by Dr. Krishna Kumari Challa on June 4, 2024 at 9:23am

Study sheds new light on the contribution of dopamine to reinforcement learning

The neurotransmitter dopamine has often been linked to pleasure-seeking behaviors and making stimuli paired with rewards  valuable. Nonetheless, the processes through which this key chemical messenger contributes to learning have not yet been fully elucidated.

Researchers carried out a study now aimed at better understanding how dopaminergic neurons (i.e., brain cells supporting the production of dopamine) support reward-based learning. Their findings, published in Nature Neuroscience, suggest that rather than representing the value attributed to different stimuli, these neurons contribute to the formation of new mental associations between stimuli and reward (or other neutral stimuli), which help us form cognitive maps of our environment.

This recent research has shown that firing of dopamine neurons act as the brain's teaching signal. This occurs whenever something new or salient happens, which helps us learn to associate events together to make a new memory. Critically, this work has shown that dopamine neurons do this without making things 'valuable' or 'good' in and of themselves.

This work is at odds with past studies that have defined dopamine as the neurotransmitter producing "happiness" or "pleasure." However, if dopaminergic neurons do not carry value signals, they should be unable to attribute positive or pleasurable qualities to specific experiences or actions.

The results of their experiment suggest that when dopamine neurons fire in everyday life, they're not making things valuable. Instead, they function to help us form new memories or how things in our environment are related. In a case where dopamine neurons fire more than they are supposed to (e.g., when taking drugs of abuse), this may be encoded in the brain as a rewarding event that makes us more likely to seek out drugs in future.

Overall, this recent study by researchers could greatly contribute to the understanding of dopamine and its role in reward-based (i.e., reinforcement) learning. In particular, their findings suggest that dopamine neurons do not carry value signals that attach pleasure or happiness to stimuli in the environment.

The researchers are now interested in finding how different dopamine circuits contribute to different types of learning and how this helps us to create a complex but unified representation of our environment.

Samuel J. Millard et al, Cognitive representations of intracranial self-stimulation of midbrain dopamine neurons depend on stimulation frequency, Nature Neuroscience (2024). DOI: 10.1038/s41593-024-01643-1

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