Comment

Comment by Dr. Krishna Kumari Challa on September 19, 2023 at 10:30am

Study finds significant chemical exposures in women with cancer

In a sign that exposure to certain endocrine-disrupting chemicals may be playing a role in cancers of the breast, ovary, skin and uterus, researchers have found that people who developed those cancers have significantly higher levels of these chemicals in their bodies.

While it does not prove that exposure to chemicals like PFAS (per- and poly-fluoroalkyl substances) and phenols (including BPA) led to these cancer diagnoses, it is a strong signal that they may be playing a role and should be studied further.

The study showed that particularly for women, higher exposure to PFDE, a long-chained PFAS compound, had double the odds of a previous melanoma diagnosis; women with higher exposure to two other long-chained PFAS compounds, PFNA and PFUA, had nearly double the odds of a prior melanoma diagnosis.

The study showed a link between PFNA and a prior diagnosis of uterine cancer; and women with higher exposure to phenols, such as BPA (used in plastics) and 2,5-dichlorophenol (a chemical used in dyes and found as a by-product in wastewater treatment), had higher odds of prior ovarian cancer diagnoses.

The study concludes that Since PFAS make up thousands of chemicals, one way to reduce exposures is for EPA to regulate PFAS as a class of chemicals, rather than one at a time.

Cathey, A.L et al, Exploratory profiles of phenols, parabens, and per- and poly-fluoralkyl substances among NHANES study participants in association with previous cancer diagnoses, Journal of Exposure Science & Environmental Epidemiology (2023). DOI: 10.1038/s41370-023-00601-6

Comment by Dr. Krishna Kumari Challa on September 19, 2023 at 10:02am

Q: Why are the climate activists vandalizing art and museums?

Answer: "How do you feel when you see something beautiful and priceless art work apparently being destroyed before your eyes? Do you feel outraged? Good. Where is that feeling when you see the planet being destroyed?"

• A statement by a Just Stop Oil activist, who had taken part in vandalizing a work by Vermeer in The Hague

Lily Kinyon et al, When, where, and which climate activists have vandalized museums, npj Climate Action (2023). DOI: 10.1038/s44168-023-00054-5

Comment by Dr. Krishna Kumari Challa on September 19, 2023 at 9:54am

 The energy costs of information processing in biological systems

The behaviors, physiology and existence of living organisms is supported by countless biological processes, which entail the communication between cells and other molecular components. These molecular components are known to transmit information to each other in various ways, for instance via processes know as diffusion and electrical depolarization or by exchanging mechanical waves.

Researchers recently carried out a study aimed at calculating the energetic cost of this transfer of information between cells and molecular components. Their paper, published in Physical Review Letters, introduces a new tool that could be used to study cellular networks and better understand their function.

 They had tried to experimentally determine how much energy neurons spend when sending information. They  found that this energy expenditure ranged between 10⁴-10⁷ K_BT/bit depending on details, which is far higher than the 'fundamental' bound of ~ K_BT/bit, sometimes called the the Landauer bound which must be paid to erase a bit of information.

A further objective of the recent study was to determine whether optimizing these energetic costs could shed light on the reasons why molecular systems communicate with each other using distinct physical mechanisms in different situations. For instance, while neurons typically communicate with each other via electrical signals, other types of tells can communicate via the diffusion of chemicals.

They wanted to understand in what regime each of these (and others) would be best in terms of an energy cost per bit.

 Samuel J. Bryant et al, Physical Constraints in Intracellular Signaling: The Cost of Sending a Bit, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.068401

Comment by Dr. Krishna Kumari Challa on September 19, 2023 at 9:39am

Can a vitamin transform natural killer cells into a cancer therapy? Scientists think the answer is yes

Cancer patients appeared to benefit from natural killer cells obtained from donors in an experimental method of treating cancer that involved an aggressive army of immune system fighters endowed with the ability to home in on malignant cells and destroy them.

The natural killer cells were pre-treated with nicotinamide, a compound widely known to most people as niacin, or vitamin B₃. It's a substance with a special affinity for natural killer cells, enhancing their capacity to annihilate cancers. Once primed in the laboratory, these natural killers are ready to be unleashed against formidable targets. The evolving methodology has shown promise in a preliminary study aimed at forcing hard-to-treat cancers of the blood into remission.

Prior to the new research, which is published in Science Translational Medicine, attempts by other teams to use natural killer cell infusions as a therapeutic for leukemias, lymphomas and other blood malignancies, weren't always effective. Doctors were confronted with a problem: some people simply didn't respond to the investigational treatment, which was offered after standard therapy failed.

Now, in a unique take on this emerging form of cancer treatment, medical scientists have devised a way to boost the effectiveness of natural killer cells, enhancing their role as a therapeutic. The innovative approach boosted the impact of natural killer cells and brought about remissions in patients with otherwise recalcitrant cancers.

The combination of nicotinamide-enhanced natural killer cells and monoclonal antibody treatment was safe in 30 patients, including 20 with relapsed or difficult-to-treat non-Hodgkin lymphoma. Among 19 patients with non-Hodgkin lymphoma, 11 demonstrated a complete response and three had a partial response within 28 days of treatment. Nicotinamide appears to protect the natural killer cells from oxidative stress, while enhancing their ability to home in on lymph nodes, the scientists found.

Frank Cichocki et al, Nicotinamide enhances natural killer cell function and yields remissions in patients with non-Hodgkin lymphoma, Science Translational Medicine (2023). DOI: 10.1126/scitranslmed.ade3341

Comment by Dr. Krishna Kumari Challa on September 18, 2023 at 10:01am

Researchers took a fresh look at the flat ΛCDM concordance cosmology model as a potential source of mistaken assumptions. If cosmology was a game of chess, this would be the board and pieces as laid out on general relativity's tiles, moved by dark energy's push, and aligned by dark matter's gravitational influences.

Rewinding the chess pieces we see today, we can effectively see how the game began, from a momentary blink of rapid inflation to a time where the first stars collapse, to the formation of galaxies and their eventual emergence into gargantuan, interconnected threads.
If for some reason this process deviated from what's predicted by the concordance model, impeding the growth of the Universe's large-scale structure, the tension between the different measures of the Universe's accelerating expansion would vanish.

The researchers used a combination of measurements involving ripples in the cosmic web, gravitational lensing events, and details in the cosmic microwave background to come to a statistically convincing conclusion that the cosmic web is growing slower than the flat ΛCDM concordance cosmology model predicts.

"The difference in these growth rates that we have potentially discovered becomes more prominent as we approach the present day," says Nguyen.

"These different probes individually and collectively indicate a growth suppression. Either we are missing some systematic errors in each of these probes, or we are missing some new, late-time physics in our standard model."

While there are no obvious contenders for what might put the brakes on the growth of the cosmic web, future measurements of the Universe's large scale structure might at least hint at whether there's a need to explore the idea further.
The Universe has taken 13.7 billion years to look this good. We can stand to wait a few more years to work out the secrets to such fine looking cosmological wrinkles.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.111001

Part 2

**

Comment by Dr. Krishna Kumari Challa on September 18, 2023 at 9:57am

Something Is Suppressing The Growth of The Universe, Physicists Say

Seen through a giant's eyes, our Universe's galaxies cling like foam to the surface of an eternal ocean, drawing into clumps and strings around inky voids. This sparkling web has taken eons to come together, congealing gradually under gravity's guidance out of what was, billions of years ago, an evenly-spread fog of white-hot particles fresh out of the Big Bang's oven.

Slow as this growth seems to us mere mortals, University of Michigan physicists Nhat-Minh Nguyen, Dragan Huterer, and Yuewei Wen want to slow it down even further, fixing one of science's most vexing problems in the process.
Their suggested tweak to the model that currently best describes our Universe could resolve a significant conflict in observations of space's expanding waistline.

Complain as you might that you can't get something for nothing these days, there's more empty space up there today than there was yesterday. Something is causing nothingness to grow, squeezing its way into the gaps between galaxies to gently push the large scale structure of the Universe apart at an ever increasing rate.
Since we don't know what is behind this mysterious shoving, we refer to it as dark energy.

"If gravity acts like an amplifier enhancing matter perturbations to grow into large-scale structure, then dark energy acts like an attenuator damping these perturbations and slowing the growth of structure," says Nguyen, the lead author of an investigation into the large-scale structure's growth.

"By examining how cosmic structure has been clustering and growing, we can try to understand the nature of gravity and dark energy."

The precise rate of expansion, known as the Hubble constant (H0), isn't at all clear. Measure the way certain kinds of exploding stars retreat into the distance, you might get an acceleration of 74 kilometers per second per megparsec. Using the 'light echo' of stretched radiation still bouncing about after the Big Bang – the cosmic microwave background (CMB) – H0 is closer to around 67 kilometers per second.

That might not seem like much of a difference, but the discrepancy has persisted through enough investigations that it can no longer be dismissed as some trivial error.
part1

Comment by Dr. Krishna Kumari Challa on September 18, 2023 at 9:26am

Matter found to comprise 31% of the total amount of matter and energy in the universe

One of the most interesting and important questions in cosmology is, "How much matter exists in the universe?" An international team of scientists has now succeeded in measuring the total amount of matter for the second time. Reporting in The Astrophysical Journal, the team determined that matter makes up 31% of the total amount of matter and energy in the universe, with the remainder consisting of dark energy.

Cosmologists think that only about 20% of the total matter is made of regular or 'baryonic' matter, which includes stars, galaxies, atoms, and life. About 80% is made of dark matter, whose mysterious nature is not yet known but may consist of some as-yet-undiscovered subatomic particles.

The team used a well-proven technique to determine the total amount of matter in the universe, which is to compare the observed number and mass of galaxy clusters per unit volume with predictions from numerical simulations.

The number of clusters observed at the present time, the so-called 'cluster abundance,' is very sensitive to cosmological conditions and, in particular, the total amount of matter. A higher percentage of the total matter in the universe would result in more clusters being formed. But it is difficult to measure the mass of any galaxy cluster accurately as most of the matter is dark, and we cannot see it directly with telescopes.

To overcome this difficulty, the team was forced to use an indirect tracer of cluster mass. They relied upon the fact that more massive clusters contain more galaxies than less massive clusters (mass richness relation: MRR). Because galaxies consist of luminous stars, the number of galaxies in each cluster can be utilized as a way of indirectly determining its total mass.

By measuring the number of galaxies in each cluster in their sample from the Sloan Digital Sky Survey, the team was able to estimate the total mass of each of the clusters. They were then able to compare the observed number and mass of galaxy clusters per unit volume against predictions from numerical simulations.

The best-fit match between observations and simulations was with a universe consisting of 31% of the total matter, a value that was in excellent agreement with that obtained using cosmic microwave background (CMB) observations from the Planck satellite. Notably, CMB is a completely independent technique.

They have succeeded in making the first measurement of matter density using the MRR, which is in excellent agreement with that obtained by the Planck team using the CMB method.

This work further demonstrates that cluster abundance is a competitive technique for constraining cosmological parameters and complementary to non-cluster techniques such as CMB anisotropies, baryon acoustic oscillations, Type Ia supernovae, or gravitational lensing.

 Mohamed H. Abdullah et al, Constraining Cosmological Parameters Using the Cluster Mass–Richness Relation, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/ace773

Comment by Dr. Krishna Kumari Challa on September 17, 2023 at 12:45pm

World falling dangerously short of climate goals: UN

A world facing catastrophic climate change is perilously off course in meeting goals for slashing carbon pollution and boosting finance for the developing world, according to the UN's first official progress report out Friday.

The 2015 Paris treaty has successfully driven climate action, but "much more is needed now on all fronts," said the report, which will underpin a crucial climate summit in Dubai at the end of the year.

"The world is not on track to meet the long-term goals of the Paris Agreement," including capping global warming at 1.5 degrees Celsius above mid-19th century levels, the report said.

Achieving net zero carbon emissions by 2050—another Paris goal—will also require phasing out the burning of all fossil fuels whose emissions cannot be captured or compensated.

The stocktake report also says that clean power must be dramatically ramped up, according to the first UN scorecard of the world's progress in meeting Paris Agreement climate goals.

"Scaling up renewable energy and phasing out all unabated fossil fuels are indispensable elements of just energy transitions to net zero emissions," it said.

"Unabated" refers to the absence of any technology that removes carbon emissions, either at the source or from the atmosphere.

Emissions have already peaked in developed and a few developing countries, but are continuing to rise in many of the world's largest economies.

The global stocktake report is a call for radical and immediate action to meet the goals of the Paris Agreement. 

The stocktake also highlights the need to rapidly and radically scale up financial support to developing nations so they can adapt to climate amplified weather disasters that are already eating away at their economies.

Source: News Agencies

Comment by Dr. Krishna Kumari Challa on September 17, 2023 at 12:29pm

Why bats carry viruses that have higher fatality rates in humans than those from other mammals

A small team of biologists and evolutionists reports why bats carry viruses that cause higher fatality rates when jumping to humans than those that come from any other mammal. In their study, reported on the open-access site PLOS Biology, the group used data from past research efforts to model the growth of viruses within bat populations as well as their spread to other animals.

Prior research has shown that when a virus jumps from bats to humans, the results can be deadlier for humans than when viruses jump from other mammals. The reason has been a matter of debate.

In this new effort, the team used data from prior research efforts, along with mathematics and modeling, to show that it is due to an innate tolerance for inflammation in bats, which, the researchers suggest, arose with their ability to fly.

To come to this conclusion, the research team first obtained data from other studies about the impact of several viruses on the immune systems of bats that had also jumped to humans. They then used that data in a mathematical model to show how a virus optimizes its chances of survival (by spreading from host to host before a host dies) by balancing transmission gains with degree of virulence. They found that a key feature of bat physiology—its ability to fly—was related to its tolerance for inflammation. This was pertinent because it made the bat more tolerant of viruses when infected. That allowed for a high growth rate of viruses in bats. And that, the researchers point out, is why the same virus would be more deadly in humans—we have a lower tolerance for inflammation. A lower tolerance, they note, leads to more grave symptoms, such as lungs that are no longer able to process enough air.

The research team extended their study to include 19 other mammals as a way to predict viral growth and the likely impact of a jump to humans in a general sense. They found reason to think that there is a low probability of a lethal virus that spreads easily from bats or other mammals to humans.

 Cara E. Brook et al, Reservoir host immunology and life history shape virulence evolution in zoonotic viruses, PLOS Biology (2023). DOI: 10.1371/journal.pbio.3002268

Comment by Dr. Krishna Kumari Challa on September 16, 2023 at 9:54am

Notorious fungus Aspergillus fumigatus completely scrambles its genome after just one bout of sex

 Researchers have found that Aspergillus fumigatus produces more meiotic crossovers than any other organism. This means that the fungus can establish its complex resistance mechanism after just one cycle of sexual reproduction. The discovery uncovers a possible cause of the rapid spread of hard-to-treat fungal infections.

It also makes it difficult to identify the source of an infection with a resistant fungus. 

Aspergillus fumigatus is naturally widespread in our environment. In fact, we inhale the spores of this fungus every day. For healthy people, this causes no problems. But it can be dangerous for seriously ill patients.

For example, it's risky for people who are in the ICU, or receiving chemotherapy, or those who have undergone an organ transplant. Infections caused by Aspergillus fumigatus are therefore treated medically with azoles, which are antifungal agents. The problem is that the fungus is increasingly resistant to this treatment, and this can be fatal to patients.

One of the causes of the resistance mechanism in the fungus is believed to be the frequent use of azoles in agriculture. Farmers and horticulturists may not use azoles specifically to combat Aspergillus fumigatus, but they do use them to tackle other fungi. Exposure to azoles has enabled Aspergillus fumigatus to develop a resistance mechanism. Compost heaps, where the fungus naturally thrives, are particular hotspots for resistance selection. And that eventually works its way into hospitals. Even patients who have never been treated with an azole can already be carrying an azole-resistant fungus.

There are isolates that have many  genetic differences to those of the fungus at the farm, but also many similarities. This may be due to the sexual reproduction of the fungus, which the researchers looked at in their PLoS Biology study.

The researchers  focused on the number of crossovers per chromosome. In humans, that would be three to four on average. This results in combinations of genes from either parent remaining strongly linked. But in Aspergillus fumigatus, they detected up to 30 crossovers. That's the highest number ever found in an organism.

This means that a single act of sexual reproduction leads to a 'complete reshuffling' of the genome—the genetic makeup of the organism. "This causes enormous variation in the population, even within a relatively limited environment.

It makes it very difficult to identify the transmission route of an infection, from the environment to a patient. The fungus can also efficiently reproduce asexually as well as sexually. So you could simultaneously find the fungus with identical genomes in isolates located thousands of kilometers apart. That makes it very challenging to figure out the transmission of this fungus.

Ben Auxier et al, The human fungal pathogen Aspergillus fumigatus can produce the highest known number of meiotic crossovers, PLOS Biology (2023). DOI: 10.1371/journal.pbio.3002278

• ‹ Previous
• 1
• …
• 283
• 284
• 285
• 286
• 287
• …
• 1027
• Next ›
• Page