Comment

Comment by Dr. Krishna Kumari Challa on August 4, 2023 at 10:12am

Geostationary satellite reveals widespread midday depression in dryland photosynthesis during 2020 heat wave

We are facing unprecedented heat waves . These conditions have resulted in severe consequences for both human and nature systems, including dire water shortages, rampant wildfires, substantial agricultural losses, and increased human mortality.

The places where these heat waves occur, ecosystems face exacerbated water stress due to more frequent and protracted droughts and heat waves, which can profoundly impair ecosystem photosynthesis and carbon uptake, in turn affecting the global carbon cycle.

Investigating vegetation photosynthesis at various time scales provides valuable insights into vegetation growth, carbon uptake, and environmental interactions. Traditional polar-orbiting satellite observations have aided in monitoring gross primary production (GPP) at longer scales (e.g., monthly, annual), but they are limited in capturing diurnal variations. Fortunately, in recent years, emerging new-generation geostationary satellites with sub-daily sampling capability, provide unique opportunities to study diurnal variations of vegetation photosynthesis and their responses to environmental conditions over the course of day at large spatial scales.

In a recent study, scientists estimated hourly GPP across the Conterminous U.S. based on observations from Geostationary Operational Environmental Satellite-R (GOES-R), and then investigated how the diurnal cycle of photosynthesis responded to the severe late-summer heat wave of 2020. The work is published in the journal Science Advances.

The study provides an exploration of heat wave impacts on the diurnal dynamics of photosynthesis at a continental scale, revealing a widespread midday and afternoon depression of photosynthesis in dryland ecosystems during the heat wave. In the study the researchers examine the environmental regulation of diurnal photosynthesis dynamics across diverse ecosystems, and illustrate how current radiation-based methods for upscaling polar-orbiting satellite snapshots to daily means may under- or overestimate daily GPP.

They found a widespread midday and afternoon depression in ecosystem photosynthesis during the heat wave .

The diurnal metrics exhibit divergent responses to the heat wave across vegetation types and along aridity gradients. Overall, shrubland and grassland are more sensitive to the heat wave than the other vegetation types.

The impact of the heat wave on the diurnal cycle of photosynthesis is predominantly observed in arid and semiarid regions with an aridity index (AI) below 0.6. They found that the largest GPP loss occurred at noon or during the afternoon for the majority of western regions, later than the GPP peak hour during the heat wave year, further substantiating the asymmetric influence of heat waves on diurnal photosynthesis fluctuations.

 Xing Li et al, New-generation geostationary satellite reveals widespread midday depression in dryland photosynthesis during 2020 western U.S. heatwave, Science Advances (2023). DOI: 10.1126/sciadv.adi0775

Comment by Dr. Krishna Kumari Challa on August 4, 2023 at 9:31am

Study shows people experience emotions with computer-generated art

Computers and artificial intelligence (AI) are becoming increasingly important in the art world. AI-generated artworks fetch millions at auction, and artists routinely use algorithms to create aesthetic content.

Now, a team of researchers  has conducted experiments showing that, contrary to popular intuition, people perceive emotions and intentions when viewing art, even when they know the work was generated by a computer. The study was published in the journal Computer in Human Behavior.

Jason Allen’s A.I.-generated work, “Théâtre D’opéra Spatial,” ( Source: nytimes)

Researchers investigated whether people respond emotionally to, or perceive intentionality in, art that they believe was generated by a computer.

The researchers presented participants with abstract black-and-white artworks, explaining that the artworks were either randomly generated by a computer or intentionally created by a person to evoke emotion.

Before viewing each artwork, participants were told whether it was supposedly created by a computer or a person; this information was true in half of the cases. The participants were then asked to rate the artworks based on several dimensions. In addition, they were asked to indicate the emotions they personally experienced while viewing the artworks, the emotions they believed the artworks were intended to evoke in viewers, and the emotions, if any, they believed the artists themselves felt while creating the artworks.

The results showed that participants almost always experienced some emotion and perceived some level of intentionality.

The study thereby provides new empirical evidence that people can form emotional attachments to computer-generated art. So contrary to common assumptions, people seem to perceive emotions and intentions even when they know that something was created by a computer. However, they reported stronger emotions and rated the artwork more positively if it had actually been created by a person—even when they got the wrong information that the art was computer-generated.

Thus, the results also show that a subtle but significant difference in emotional impact remains between human and artificial art. This could point to specific characteristics in man-made art that are perceived by viewers.

Overall, the results raise new questions for human-computer interaction and the growing role of AI as a creative entity in art, design, and entertainment.

 Theresa Rahel Demmer et al, Does an emotional connection to art really require a human artist? Emotion and intentionality responses to AI- versus human-created art and impact on aesthetic experience., Computers in Human Behavior (2023). DOI: 10.1016/j.chb.2023.107875

Comment by Dr. Krishna Kumari Challa on August 4, 2023 at 9:22am

Study reveals unexpected importance of the thymus in adults

The thymus gland—which produces immune T cells before birth and during childhood— is often regarded as nonfunctional in adults, and it's sometimes removed during cardiac surgery for easier access to the heart and major blood vessels.

New research  by investigators and  published in the New England Journal of Medicine has uncovered evidence that the thymus is in fact critical for adult health generally and for preventing cancer and perhaps autoimmune disease.

To determine whether the thymus provides health benefits to adults, the team evaluated the risk of death, cancer, and autoimmune disease among 1,146 adults who had their thymus removed during surgery and among 1,146 demographically matched patients who underwent similar cardiothoracic surgery without thymectomy. The scientists also measured T cell production and blood levels of immune-related molecules in a subgroup of patients.

Five years after surgery, 8.1% of patients who had a thymectomy died compared with 2.8% of those who did not have their thymus removed, equating to a 2.9-times higher risk of death. Also during that time, 7.4% of patients in the thymectomy group developed cancer compared with 3.7% of patients in the control group, for a 2.0-times higher risk.

The thymus is absolutely required for health. If it isn't there, people's risk of dying and risk of cancer is at least double. This indicates that the consequences of thymus removal should be carefully considered when contemplating thymectomy.

In an additional analysis involving all patients in the thymectomy group with more than five years of follow-up, the overall mortality rate was higher in the thymectomy group than in the general U.S. population (9.0% vs. 5.2%), as was mortality due to cancer (2.3% vs. 1.5%).

Kameron A. Kooshesh et al, Health Consequences of Thymus Removal in Adults, New England Journal of Medicine (2023). DOI: 10.1056/NEJMoa2302892

Comment by Dr. Krishna Kumari Challa on August 4, 2023 at 9:15am

A new discovery in a cause of inner-ear bone loss

Chronic inflammation of the middle ear can cause several problems and complications that can affect a person's hearing and balance. One such problem is the formation of a cholesteatoma, which is an abnormal collection of cells in the ear that can cause bone erosion if left untreated. In turn, this can cause symptoms such as hearing loss, dizziness, facial paralysis, and even a brain infection.

In a study published recently in Nature Communications, researchers have revealed the cause of cholesteatomas, which may help in developing new therapies for patients who are suffering from this disease.

Cholesteatomas are made up of cysts or bumps in the ear that consist of skin, collagen fibers, skin cells, fibroblasts, keratin, and dead tissue. There are many theories on how these cholesteatomas can cause bone erosion, including the activation of cells responsible for the breakdown of the minerals and matrix of the bone, the presence of inflammatory markers and enzymes, and the accumulation and pressure from dead cells and tissues in the ear. However, the exact mechanism for the creation of cholesteatomas remains unknown.

A cholesteatoma can still return or happen again even after its surgical removal, so it is important to know what is actually causing it.

To investigate this, researchers looked at human cholesteatoma tissues that were surgically removed from patients. A process called single-cell RNA sequencing analysis was employed to identify cells responsible for triggering bone erosion; these were called osteoclastogenic fibroblasts. This study demonstrated how these fibroblasts expressed an abundant amount of activin A, a molecule that regulates different physiologic functions of the body. The presence of activin A is said to cause bone erosion through a process in which specialized cells initiate bone resorption through a process wherein the minerals and matrix of the bones are broken down and absorbed by the body. 

The researchers were successful in showing the relationship between activin A and bone erosion in cholesteatoma.

Currently in clinical settings, the only effective treatment for cholesteatomas is complete surgical removal. However, the discovery of how a cholesteatoma can cause bone erosion in this study offers new hope for developing novel medical treatments as first-line management for cholesteatomas.

Single-cell transcriptomics of human cholesteatoma identifies an activin A-producing osteoclastogenic fibroblast subset inducing bone destruction, Nature Communications (2023). DOI: 10.1038/s41467-023-40094-3

Comment by Dr. Krishna Kumari Challa on August 4, 2023 at 9:02am

Genetic predisposition to atrial fibrillation accelerated by air pollution, research suggests

Research has connected the effects of air pollutants on the risk of atrial fibrillation (AF). In a paper, "Air pollution, genetic susceptibility, and the risk of atrial fibrillation: A large prospective cohort study," published in PNAS, researchers find long-term exposure to air pollutants increases the risk of AF, particularly among individuals with high genetic susceptibility.

Air pollutants have long been associated with cardiovascular diseases. Recent studies have linked short-term exposure to these pollutants with acute exacerbations of AF. Studies on twins suggest that genetic susceptibility plays a big part in the risk of AF, but these risk factors explain only about half of AF cases.

The current study focuses on the cumulative damage caused by long-term exposure to these pollutants, revealing an association between increased concentrations of particulate matter with aerodynamic diameters smaller than 2.5 μm (PM_2.5), particulate matter with diameters of 10 μm (PM₁₀), nitrogen dioxide (NO₂), and nitrogen oxide and the underlying genetic risk of AF.

Despite the visible haze that can come with smoke, dust or vehicle emissions, particle pollution is comprised of tiny non-visible elements under 10 μm, and these can travel deep into the lungs. For reference, the average width of human hair is around 70 μm.

The particles can be hundreds of different chemicals depending on their source. Direct emissions from agricultural, automotive, industrial, fire or construction sites will reflect what is coming from those sources. In the atmosphere, more environmentally complex sources like those emitted from power plants, heavy industries and automobile emissions can undergo reactions to produce chemicals like sulfur dioxide and nitrogen oxides.

When combining genetic susceptibility with high air pollutant levels, participants exposed to high air pollutants with high genetic risk had approximately 149–182% higher risk of AF than individuals with low genetic risk factors.

The study also found a significant additive risk interaction between PM₁₀ and NO₂ and genetic risk, with approximately 16.4–35.1% of cases attributable to the joint effects of these pollutants and genetic predisposition.

The combined effects of  air pollutants and genetic risk showed a dose-response manner, such that exposure to high air pollutant levels and having high genetic risk resulted in high AF chances.

Yudiyang Ma et al, Air pollution, genetic susceptibility, and the risk of atrial fibrillation: A large prospective cohort study, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2302708120

Comment by Dr. Krishna Kumari Challa on August 3, 2023 at 12:59pm

Zap these cells for insulin
Genetically engineered human cells that produce insulin when stimulated by a small electric current could one day be used to develop insulin implants for people with type 1 diabetes. Reactive oxygen species — unstable oxygen-containing radicals that are produced when a current is applied — are involved in a chain that switches on a gene needed to make insulin. Researchers implanted the cells into mice with high blood sugar and used acupuncture needles to apply a current — which triggered the cells to release insulin.

https://www.nature.com/articles/s42255-023-00850-7.epdf?sharing_tok...

---

Chatbots are coming to science search Scopus, Dimensions and Web of Science are introducing conversational search using large language models (LLMs). Scopus AI is intended to be a light, playful tool to help researchers quickly get summaries of topics that they’re unfamiliar with. The bot uses a version of GPT-3.5 to return a fluent summary paragraph, together with references and further questions to explore. The Dimensions chatbot first uses a search engine to retrieve relevant articles and then an Open AI GPT model to generate a summary paragraph around the top-ranked abstracts. Both tools will probably be released widely by the end of this year or the beginning of the next. It’s unclear when Web of Science’s LLM-powered search will become available.

https://www.nature.com/articles/d41586-023-02470-3?utm_source=Natur...

Comment by Dr. Krishna Kumari Challa on August 3, 2023 at 11:42am

The membranes surrounding viruses are made of different molecules than the virus itself, as lipids are acquired from the host to form membranes. One such lipid, phosphatidylserine, is present in the membrane on the outside of viruses, but is sequestered towards the interior of human cells under normal conditions.

Because phosphatidylserine is found on the exterior of viruses, it can be a specific target for peptoids to recognize viruses, but not recognize—and therefore spare—our own cells. Moreover, because viruses acquire lipids from the host rather than encoding from their own genomes, they have better potential to avoid antiviral resistance.

The researchers tested seven peptoids against the four viruses. They found that the peptoids inactivated all three enveloped viruses—Zika, Rift Valley fever, and chikungunya—by disrupting the virus membrane, but did not disrupt coxsackievirus B3, the only virus without a membrane.

Moreover, chikungunya virus containing higher levels of phosphatidylserine in its membrane was more susceptible to the peptoids. In contrast, a membrane formed exclusively with a different lipid named phosphatidylcholine was not disrupted by the peptoids, suggesting that phosphatidylserine is crucial in order for peptoids to reduce viral activity.

The researchers are continuing pre-clinical studies to evaluate the potential of these molecules in fighting viruses and to understand if they can overcome the development of resistance. Their peptoid-focused approach may hold promise for treating a wide range of viruses with membranes that can be difficult to treat, including Ebola, SARS-CoV-2, and herpes.

 Peptidomimetic Oligomers Targeting Membrane Phosphatidylserine Exhibit Broad Antiviral Activity, ACS Infectious Diseases (2023). DOI: 10.1021/acsinfecdis.3c00063 , pubs.acs.org/doi/abs/10.1021/acsinfecdis.3c00063

Part 2

Comment by Dr. Krishna Kumari Challa on August 3, 2023 at 11:40am

Novel molecules fight viruses by bursting their bubble-like membranes

Antiviral therapies are notoriously difficult to develop, as viruses can quickly mutate to become resistant to drugs. Viruses have different proteins on their surfaces that are often the targets of therapeutics like monoclonal antibodies and vaccines. But targeting these proteins has limitations, as viruses can quickly evolve, changing the properties of the proteins and making treatments less effective. These limitations were on display when new SARS-CoV-2 variants emerged that evaded both the drugs and the vaccines developed against the original virus.

But what if a new generation of antivirals ignores the fast-mutating proteins on the surface of viruses and instead disrupts their protective layers?

Scientists found an Achilles heel of many viruses: their bubble-like membranes. Exploiting this vulnerability and disrupting the membrane is a promising mechanism of action for developing new antivirals.

In a new study published Aug. 2 in the journal ACS Infectious Diseases, the researchers show how a group of novel molecules inspired by our own immune system inactivates several viruses, including Zika and chikungunya. Their approach may not only lead to drugs that can be used against many viruses, but could also help overcome antiviral resistance.

Drawing inspiration from our immune system is the new mantra. Our innate immune system combats pathogens by producing antimicrobial peptides, the body's first line of defense against bacteria, fungi, and viruses. Most viruses that cause disease are encapsulated in membranes made of lipids, and antimicrobial peptides work by disrupting or even bursting these membranes. While antimicrobial peptides can be synthesized in the lab, they are rarely used to treat infectious diseases in humans because they break down easily and can be toxic to healthy cells. Instead, scientists have developed synthetic materials called peptoids, which have similar chemical backbones to peptides but are better able to break through virus membranes and are less likely to degrade. 

Part 1

Comment by Dr. Krishna Kumari Challa on August 2, 2023 at 1:09pm

Conjunctivitis is the swelling or inflammation of the conjunctiva, the thin, transparent layer of tissue that lines the inner surface of the eyelid and covers the white part of the eye. Causes may or may not be infectious. Allergic Conjunctivitis  ( seasonal allergies) Infectious Conjunctivitis  ( Bacterial, Viral ) Chemical Conjunctivitis ( air pollution, chlorine in water ) Ippudu ee season lo sadharanam ga vachedi viral or bacterial conjunctivitis. There are Eye drops or ointments  for Bacterial con. There are  Antibiotics too. But no drops or ointments can treat viral conjunctivitis. Antibiotics will not cure a viral infection. The virus has to run its course, which may take up to two or three weeks.  In case you have to deal with infectious people,  frequent hand washing and keeping hands away from eyes can make a difference. Don't use Common towels, soaps .Be Careful. If you feel  pain and irritation  please visit a doctor . Self medication is not good.

Comment by Dr. Krishna Kumari Challa on August 2, 2023 at 12:47pm

You shouldn't declaw tigers or other big cats

Declawing house cats to keep them from scratching people and furniture is controversial – and even banned in some countries  – but the practice is not limited to house cats. In a new study, researchers looked at the effects of declawing on larger cat species and found that declawing disproportionately impacts their muscular capabilities as compared to their smaller brethren.

Declawing is still done on large cats like lions and tigers, often in an effort to allow cubs to more safely be handled in photo opportunities or for entertainment purposes.

What people might not realize is that declawing a cat is not like trimming our fingernails; rather, it is removing part or all of the last bone of each digit. Like us, each cat finger has three bones, and declawing is literally cutting that third bone off at the joint.

The researchers looked at the muscular anatomy of over a dozen exotic cats – from smaller species including bobcats, servals and ocelots, to lions and tigers – to determine the effect of declawing on their forelimb musculature.

They measured muscle density and mass, and also examined muscle fibers from both clawed and declawed exotic cats. They found that for the larger species declawing resulted in 73% lighter musculature in the forearm’s digital flexors. These muscles are involved in unsheathing the claws. They also found that overall, forelimb strength decreased by 46% to 66%, depending on the size of the animal, and that other muscles in the forelimb did not compensate for these reductions.

With big cats, there’s more force being put through the paws. So if you alter them, it is likely that the effects will be more extreme.

This is because paw size and body mass don’t scale up at a 1:1 ratio. Paw area increases at a slower rate than does body mass (which is proportional to volume), so larger cats have smaller feet relative to their body size, and their paws must withstand more pressure.

Additionally, big cats are more reliant on their forelimbs – they bear most of the weight, and these bigger cats use their forelimbs to grapple because they hunt much larger prey. So biomechanically speaking, declawing has a more anatomically devastating effect in larger species.

Lara L. Martens et al, The Effects of Onychectomy (Declawing) on Antebrachial Myology across the Full Body Size Range of Exotic Species of Felidae, Animals (2023). DOI: 10.3390/ani13152462

• ‹ Previous
• 1
• …
• 126
• 127
• 128
• 129
• 130
• …
• 855
• Next ›
• Page