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Comment by Dr. Krishna Kumari Challa on October 6, 2023 at 8:48am

 How Amazonian forest degradation and monsoon circulation are interlinked

A pair of concerned researchers, has developed a computer model that shows linkages between forest degradation in the Amazon River basin and monsoon circulation.

That research suggested that if deforestation continues in the Amazon River basin, it could lead to a tipping point at which a certain degree of change can cause permanent changes to an ecosystem. In the case of the Amazon, the change would be from rainforest to a drier, savanna-like climate.

Over the course of many years, many studies have been conducted to understand how the characteristics of the Amazon River basin work together to maintain such a large rainforest. Such studies have shown that regional water cycling along with moisture exaltation from the plants, together with sunlight and even dust blown over from Africa, all contribute to the unique ecosystem, the largest rainforest in the world. Such work has also suggested that disruptions to parts of the system, such as cutting down trees, could result in major changes to the ecosystem. And if such changes were to occur, other studies have suggested the region would change from a rainforest to one that featured a vast savanna-like climate. Such a possible change is of major concern to climate scientists because the rainforest produces a lot of the Earth's oxygen. Additionally, destruction of the trees would result in the release of carbon they sequester, likely into the atmosphere, contributing further to climate change.

In this new effort, the researchers attempted to create a model that ties together degradation of the rainforest and monsoon circulation to show how and why a tipping point might be reached. To create their nonlinear dynamical model, the pair used data from other models that have been built over the past 40 years to simulate conditions in the rainforest. They also added weather data for the same period, including rainfall amounts, wind speeds and direction, and degree of evapotranspiration. They then modeled the rainforest in its original state to serve as a starting point. Next, they tweaked parameters to see the effects on the entire system. The model showed that cutting down trees at current rates in the Amazon region would indeed lead to a tipping point. They conclude that ecosystems with a feedback loop, such as the Amazon River basin, are particularly sensitive to change.

Nils Bochow et al, The South American monsoon approaches a critical transition in response to deforestation, Science Advances (2023). DOI: 10.1126/sciadv.add9973

Comment by Dr. Krishna Kumari Challa on October 5, 2023 at 12:08pm

Maybe volcanoes doomed the dinosaurs

A machine-learning algorithm suggests that volcanic activity, rather than an asteroid,.... The algorithm simulated 300,000 scenarios of different amounts of volcanic gases until it found one that matched data from fossils. The gases would have started to cause dinosaur-dooming climate chaos long before the asteroid impact. “You can actually recreate the environmental conditions that could cause a dinosaur extinction solely by volcanism, as if the asteroid weren’t there,” says computational geologist and study co-author Alexander Cox. “But of course, we can't discount the fact that the asteroid definitely didn't cheer up the dinosaurs.”

https://www.science.org/doi/10.1126/science.adh3875

Comment by Dr. Krishna Kumari Challa on October 5, 2023 at 12:05pm

What is anaphylaxis?

Comment by Dr. Krishna Kumari Challa on October 5, 2023 at 11:52am

Nobel Prize in chemistry for work on quantum dots, used in electronics and medical imaging

Three scientists won the Nobel Prize in chemistry Wednesday for their work on quantum dots—tiny particles just a few nanometers in diameter that can release very bright colored light and whose applications in everyday life include electronics and medical imaging.

Moungi Bawendi of MIT, Louis Brus of Columbia University, and Alexei Ekimov of Nanocrystals Technology Inc., were honored for their work with the tiny particles that "have unique properties and now spread their light from television screens and LED lamps," according to the Royal Swedish Academy of Sciences, which announced the award in Stockholm.

Quantum dots are tiny inorganic particles that glow a range of colors from red to blue when exposed to light. The color they emit depends upon the size of the particle.

Scientists can engineer the dots from materials that include gold to graphene to cadmium, and create their color by controlling their size. The tiniest particles, in which electrons are most tightly confined, emit blue light. Slightly larger particles, in which electrons bounce around a longer wavelength, emit red light.

Chemists sometimes compare the size of the particle itself to a confining box.

The underlying "particle in a box" theory of quantum mechanics was first described nearly a century ago. But it wasn't until several decades later that scientists could manufacture quantum dots in a lab.

In the 1980s, Ekimov, 78, and Brus, 80, honed the theory and developed early laboratory techniques for creating particles that emit varying colors by adjusting sizes. In 1993, Bawendi, 62, developed new chemical methods for producing the particles quickly and uniformly—which soon enabled a variety of scalable commercial applications, including in electronics displays.

www.nobelprize.org/uploads/202 … emistryprize2023.pdf

Comment by Dr. Krishna Kumari Challa on October 4, 2023 at 12:24pm

When fire & ice combine

Comment by Dr. Krishna Kumari Challa on October 4, 2023 at 12:10pm

Research shows humans can inherit AI biases

New research by psychologists provides evidence that people can inherit artificial intelligence biases (systematic errors in AI outputs) in their decisions.

The astonishing results achieved by AI systems that can, for example, hold a conversation as a human does have given this technology an image of high reliability.

More and more professional fields are implementing AI-based tools to support the decision-making of specialists to minimize errors in their decisions. However, this technology is not without risks due to biases in AI results. We must consider that the data used to train AI models reflects past human decisions. If this data hides patterns of systematic errors, the AI algorithm will learn and reproduce these errors. Indeed, extensive evidence indicates that AI systems do inherit and amplify human biases.

The most relevant finding of this new research is that the opposite effect may also occur: that humans inherit AI biases. That is, not only would AI inherit its biases from human data, but people could also inherit those biases from AI, with the risk of getting trapped in a dangerous loop. 

The most significant finding of the research was that after interaction with the AI system, those volunteers continued to mimic its systematic error when they switched to performing the diagnosis task unaided. In other words, participants who were first assisted by the biased AI replicated its bias in a context without this support, thus showing an inherited bias. This effect was not observed for the participants in the control group, who performed the task unaided from the beginning.

These results show that biased information by an artificial intelligence model can have a perdurable negative impact on human decisions. The finding of an inheritance of AI bias effect points to the need for further psychological and multidisciplinary research on AI-human interaction.

Furthermore, evidence-based regulation is also needed to guarantee fair and ethical AI, considering not only the AI technical features but also the psychological aspects of the AI and human collaboration.

Lucía Vicente et al, Humans inherit artificial intelligence biases, Scientific Reports (2023). DOI: 10.1038/s41598-023-42384-8

Comment by Dr. Krishna Kumari Challa on October 4, 2023 at 12:03pm

Why does it get hot when you rub things together? Unraveling the mystery of dynamic friction at the atomic level

Friction, an everyday phenomenon, has perplexed scientists for centuries. Though extensively researched, our understanding remains fragmented, primarily due to the multifaceted interactions that span across varying scales. Achieving an accurate grasp of the precise contact conditions between objects has been a longstanding challenge, a feat recently made possible through advancements in scanning probe microscopy.

Yet, even with these technological breakthroughs, the intricacies of dynamic friction—the force needed to maintain the movement of a molecule—have remained elusive. While scientists can measure static friction by moving a single molecule on a surface, both the measurement and theoretical understanding of dynamic friction have yet to be fully unveiled. Now, writing in Physical Review Letters and Physical Review B, a collaborative team of scientists report their groundbreaking study that dives deep into this challenge. They meticulously examined the manipulation of a carbon monoxide (CO) molecule on a single-crystal copper surface using an atomic force microscope. Backed by ab initio calculations, their findings shed light on how the CO molecule positions change relative to the microscope tip and surface, as well as the relationship between the motion of the molecule induced by the tip, energy dissipation, and both static and dynamic friction. This research stands out for its unequivocal clarity on the friction process. Not only does it provide fresh insights into a long-studied phenomenon, but it also paves the way for future studies on energy dissipation relaxation processes.

Norio Okabayashi et al, Dynamic Friction Unraveled by Observing an Unexpected Intermediate State in Controlled Molecular Manipulation, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.148001

Norio Okabayashi et al, Energy dissipation of a carbon monoxide molecule manipulated using a metallic tip on copper surfaces, Physical Review B (2023). DOI: 10.1103/PhysRevB.108.165401

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Comment by Dr. Krishna Kumari Challa on October 4, 2023 at 11:54am

The goal before the scientists now is  to develop a highly focused method or methods for blocking STING within targeted immune cells, without disrupting its other important functions. If they  can achieve that, they may have a powerful new tool for controlling hyper-inflammation.

Hannah Meibers et al, Effector Memory T cells induce innate inflammation by triggering DNA damage and a non-canonical STING pathway in dendritic cells, Cell Reports (2023). DOI: 10.1016/j.celrep.2023.113180. www.cell.com/cell-reports/full … 2211-1247(23)01192-0

Part 3

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Comment by Dr. Krishna Kumari Challa on October 4, 2023 at 11:54am

The chain reaction appears to start when T_em cells interact with dendritic cells, which serve as the immune system's primary detector of viral and bacterial invasions. These starburst shaped cells carry a large collection of receptors to detect various types of invaders. Once they encounter a harmful visitor, dendritic cells latch on and sound an alarm that instructs the rest of the immune system's machinery to begin producing T cells that are custom designed to eliminate that type of invader.

When the immune system wins the battle, most of the custom T cells stand down. But a few guards linger in the blood and other body tissues to be ready to "effect" a rapid response should the same type on infection occur again. Hence the name effector memory T cells.

However, the research team discovered that ongoing encounters with T_em cells, such as those occurring when people have autoimmunity or live in a state of chronic inflammation, actually cause DNA strands within dendritic cells to break. This, in turn, prompts a DNA repair pathway that rapidly generates large numbers of inflammatory cytokines, including IL-1b, IL-6 and IL-12.

This flood, or storm, of cytokines causes the tissue damage that occurs in autoinflammatory diseases including type 1 diabetes, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel diseases like Crohn's disease. For some people with these conditions, ongoing inflammation also increases their risk of developing cancer.

Scientists worked for the last 10 years to examine the genetic activity and cell-to-cell communications occurring behind this process. 

The team found a surprising clue when examining the transcriptional profile of dendritic cells following their interaction with T_em cells. Specifically, they detected upregulation of expression of Tmem173, which encodes for stimulator of interferon genes (STING). The STING pathway has been described in previous research as being important to detect viral infections. But when T_em cells harm dendritic cells, the STING pathway does not follow the same route that it typically does when directly responding to viral infections.

In this situation, STING teams up with the gene TRAF6 and the transcription factor NFkB to form an "axis" of activity that drives runaway production of innate inflammatory cytokines.

The researchers further reasoned that if they could prevent STING and TRAF6 from working together, they could cut off the inflammation chain reaction at an early stage. In mice gene-edited to lack the STING pathway, that's exactly what they found. When treated with a drug known to induce an intense T cell-mediated inflammatory response, these mice did not produce a flood of innate cytokines.

The mouse study involved a whole-body elimination of STING. Attempting the same in humans would not be advisable because STING is used by a number of cell types outside the immune system in necessary ways.

Part 2

Comment by Dr. Krishna Kumari Challa on October 4, 2023 at 11:49am

Science trying to take the STING out of runaway inflammation

Cytokine storm: Everybody came to know about it during the covid-19 pandemic.  But once this dangerous form of infection-triggered runaway inflammation started claiming lives by the thousands, a legion of scientists jumped into the hunt for ways to calm these storms.

Now, a study led by immunobiology experts at Cincinnati Children's, offers important new details on how two elements of our body's immune system clash with each other to prompt a chain of reactions that can release deadly floods of cell-killing, organ-damaging cytokines. Details were published Oct. 3, 2023, in the journal Cell Reports.

These findings have implications for both autoimmunity as well as cancer. Researchers have discovered an independent cell signaling pathway that allows a type of immune cell called an effector memory T cell (T_em) to become a critical driver of innate cytokine storms.

With a pathway defined, next steps include confirming whether medications that target key points along the pathway can disrupt the inflammation cycle before it becomes uncontrollable.

Part 1

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