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Comment by Dr. Krishna Kumari Challa 7 hours ago

Brain imaging study reveals connections critical to human consciousness

In a paper titled, "Multimodal MRI reveals brainstem connections that sustain wakefulness in human consciousness," published in Science Translational Medicine, a group of researchers at Massachusetts General Hospital and Boston Children's Hospital, created a connectivity map of a brain network that they propose is critical to human consciousness.

The study involved high-resolution scans that enabled the researchers to visualize brain connections at submillimeter spatial resolution. This technical advance allowed them to identify previously unseen pathways connecting the brainstem, thalamus, hypothalamus, basal forebrain, and cerebral cortex.
Together, these pathways form a "default ascending arousal network" that sustains wakefulness in the resting, conscious human brain. The concept of a "default" network is based on the idea that specific networks within the brain are most functionally active when the brain is in a resting state of consciousness. In contrast, other networks are more active when the brain is performing goal-directed tasks.

To investigate the functional properties of this default brain network, the researchers analyzed 7 Tesla resting-state functional MRI data from the Human Connectome Project. These analyses revealed functional connections between the subcortical default ascending arousal network and the cortical default mode network that contributes to self-awareness in the resting, conscious brain.

Part 1

Comment by Dr. Krishna Kumari Challa 7 hours ago

Their findings challenge previous assumptions about the backgrounds of RA, that overlooked the antibodies' diversity and complexity. This shows that RA is not just a disease occurring due to small errors, but a big structural problem in the immune system. 

The study also revealed that these ACPAs are extensively modified with sugar molecules, known as Fab glycans. Intriguingly, some antibodies had multiple sugar molecules attached. This is much more then researchers normally observe in antibody profiles.

Having extra glycans aboard, may help the ACPA antibodies pass the filter of the immune system. The immune system uses several very strict checks during antibody production, to make sure all antibodies are correct. Wrongly produced antibodies are then detected and removed. Scientists suspect that glycans could help ACPAs trick the control system, allowing ACPAs to pass through the filter and form the onset of RA.
Current efforts to develop treatments for RA are mainly geared towards eliminating autoantibodies directly. This strategy may not be effective, say the researchers. When you realize that there is such an extreme diversity in RA-related autoantibodies, it seems virtually impossible to eliminate them. A better approach may be to intervene earlier in the disease process, by targeting the malfunctioning filtering mechanism that allows autoantibodies to pass through.

Understanding these unique proteins is important, as it could ultimately also help doctors diagnose RA better. Even though RA remains an incurable disease, with an earlier diagnosis you can take better measures to control its progression.

Eva Maria Stork et al, Antigen-specific Fab profiling achieves molecular-resolution analysis of human autoantibody repertoires in rheumatoid arthritis, Nature Communications (2024). DOI: 10.1038/s41467-024-47337-x

Part 2

Comment by Dr. Krishna Kumari Challa 7 hours ago

Patients with rheumatoid arthritis have unique and complex autoantibody patterns, study reveals

Patients with rheumatoid arthritis (RA) all have a unique and diverse set of antibodies that are involved in the development of the disease. Researchers unveiled the complexity of these antibodies using powerful lab tools capable of analyzing our immune system at molecular levels. Their discovery suggests that current assumptions about the origin of RA are too simple. Their findings may point towards improved diagnostics.

Rheumatoid arthritis is a chronic autoimmune disease that primarily affects the joints, causing pain, stiffness, and swelling. It arises when the immune system mistakenly attacks the body's own tissues, leading to inflammation in the joints and potentially other organs.

The exact cause of RA remains unknown, but a crucial role is played by antibodies, special proteins made by the immune system to help fight off infections. They recognize and attack specific targets, like viruses or bacteria. Some antibodies are wrongly produced, causing them to attack our own body. Normally, our body's immune system is equipped with a 'filter' that cleans up these so-called autoantibodies. Researchers think that this mechanism is malfunctioning in RA patients.

The extend to which this filter is malfunctioning, now appears to be much greater than expected. Research  published in Nature Communications reveals that it's not just a handful of different RA-associated autoantibodies that evade the filter. On the contrary, the researchers found an extremely broad variety of these antibodies.

The team used novel mass spectrometry tools that profile specific antibodies typically seen in the blood of RA patients, which are called anti-citrullinated protein antibodies (ACPAs). They discovered that each RA patient possesses a unique and diverse set of ACPAs.

Part 1

Comment by Dr. Krishna Kumari Challa 7 hours ago

The difficulty lies in the fact that such a "second law" for quantum entanglement would require us to show that entanglement transformations can be made reversible, just like work and heat can be interconverted in thermodynamics.

It is known that reversibility of entanglement is much more difficult to ensure than the reversibility of thermodynamic transformations, and all previous attempts at establishing any form of a reversible theory of entanglement have failed. It was even suspected that entanglement might actually be irreversible, making the quest an impossible one.
In their new work, published in Nature Communications, the authors solve this long-standing conjecture by using probabilistic entanglement transformations, which are only guaranteed to be successful some of the time, but which, in return, provide an increased power in converting quantum systems.

Under such processes, the authors show that it is indeed possible to establish a reversible framework for entanglement manipulation, thus identifying a setting in which a unique entropy of entanglement emerges and all entanglement transformations are governed by a single quantity. The methods they used could be applied more broadly, showing similar reversibility properties also for more general quantum resources.
findings mark significant progress in understanding the basic properties of entanglement, revealing fundamental connections between entanglement and thermodynamics, and crucially, providing a major simplification in the understanding of entanglement conversion processes.
This not only has immediate and direct applications in the foundations of quantum theory, but it will also help with understanding the ultimate limitations on our ability to efficiently manipulate entanglement in practice.

Bartosz Regula et al, Reversibility of quantum resources through probabilistic protocols, Nature Communications (2024). DOI: 10.1038/s41467-024-47243-2

Part 2

Comment by Dr. Krishna Kumari Challa 7 hours ago

Scientists show that there is indeed an 'entropy' of quantum entanglement

Researchers have shown, through probabilistic calculations, that there is indeed, as had been hypothesized, a rule of entropy for the phenomenon of quantum entanglement.

This finding could help drive a better understanding of quantum entanglement, which is a key resource that underlies much of the power of future quantum computers. Little is currently understood about the optimal ways to make effective use of it, despite it being the focus of research in quantum information science for decades.

The second law of thermodynamics, which says that a system can never move to a state with lower entropy, or order, is one of the most fundamental laws of nature, and lies at the very heart of physics. It is what creates the "arrow of time," and tells us the remarkable fact that the dynamics of general physical systems, even extremely complex ones such as gases or black holes, are encapsulated by a single function, its entropy.

There is a complication, however. The principle of entropy is known to apply to all classical systems. Then what about quantum world?

We are now going through a quantum revolution, and it becomes crucially important to understand how we can extract and transform the expensive and fragile quantum resources. In particular, quantum entanglement, which allows for significant advantages in communication, computation, and cryptography, is crucial, but due to its extremely complex structure, efficiently manipulating it and even understanding its basic properties is typically much more challenging than in the case of thermodynamics. Part 1

Comment by Dr. Krishna Kumari Challa yesterday

First fetus-to-fetus transplant demonstrated in rats

The tissue developed into functioning kidneys and produced urine.

Surgeons in Japan have transplanted kidney tissue from one rat fetus to another, while the recipient was still in its mother's womb. Study lead Takashi Yokoo, a nephrologist at Jikei University School of Medicine in Tokyo, says the surgery is the first step to one day transplanting fetal pig kidneys into human fetuses that develop without functioning kidneys.

Transplanting an organ before birth could allow it to grow and develop with the fetus, so that the organ is functioning at birth and has less risk of rejection.

The recipient pups were born as normal after 22 days, according to a preprint (not peer reviewed). Blood vessels from the host fetus grew inside the donated tissue, lowering the risk of rejection. 

https://www.biorxiv.org/content/10.1101/2024.04.15.589452v1

https://www.nature.com/articles/d41586-024-01152-y?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa yesterday

So what should you do if you come across a green cloth book from the 19th century? First, don't be overly concerned. You would probably have to eat the entire book before you'd suffer from severe arsenic poisoning. However, casual exposure to copper acetoarsenite, the compound in the green pigment, can irritate the eyes, nose and throat.

It is more of a concern for folks who may regularly handle these books where frequent contact could result in more serious symptoms. Therefore, anyone who suspects they might be handling a Victorian-era book with an emerald green binding is advised to wear gloves and avoid touching their face. Then clean all surfaces afterwards.

To aid with the identification of these potentially hazardous books, the Poisonous Book Project has incorporated crowd-sourced data into their research. The researchers now distribute bookmarks that feature safety warnings and showcase various shades of emerald green to aid their identification. As a result, they have now identified over 238 arsenic editions from across the globe.

https://theconversation.com/many-old-books-contain-toxic-chemicals-...

Part 3

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Comment by Dr. Krishna Kumari Challa yesterday

The harmful effects of these pigments have even been implicated in Napoleon's death from stomach cancer. Napoleon was particularly keen on the new green colors, so much so that he ordered his dwelling on St Helena, where he was exiled, be painted in his favorite color.

The theory that the arsenic in the walls contributed to his death is supported by the high levels of arsenic detected in samples of his hair. Despite the clear link between the green pigments and health issues, toxic wallpapers continued to be produced until the late 19th century.
Green isn't the only color to worry about, however. Red is also of concern. The brilliant red pigment vermilion was formed from the mineral cinnabar, also known as mercury sulfide. This was a popular source of red paint dating back thousands of years. There is even evidence that neolithic artists suffered from mercury poisoning. Vermilion red sometimes appears on the marbled patterns on the inside of book covers.

Yellow has also caught the eye of the poisonous book project. In this case, the culprit is lead chromate. The bright yellow of lead chromate was a favorite with painters, not least Vincent van Gogh, who used it extensively in his most famous series of paintings: Sunflowers. For the Victorian-era bookbinders, lead chromate allowed them to create a range of colors from greens (achieved by mixing chrome yellow with Prussian blue) to yellows, oranges and browns.

Both lead and chromium are toxic. But yellow books are less of a concern than green and red. Lead chromate is not particularly soluble, making it difficult to absorb. It is, in fact, still a widely used pigment.
Part 2

Comment by Dr. Krishna Kumari Challa yesterday

Many old books contain toxic chemicals

In our modern society, we rarely consider books to be dangerous items. However, certain books contain elements so hazardous that they require scrutiny before being placed on the shelves of public libraries, bookstores or even private homes.

The Poisonous Book Project, a collaborative research project between Winterthur Museum, Garden & Library and the University of Delaware, is dedicated to cataloging such books. Their concern is not with the content written on the pages, but with the physical components of the books themselves—specifically, the colors of the covers.
The project recently influenced the decision to remove two books from the French national library. The reason? Their vibrant green cloth covers raised suspicions of containing arsenic.

This concern is rooted in historical practices in bookbinding. During the 19th century, as books began to be mass produced, bookbinders transitioned from using expensive leather covers to more affordable cloth items. To attract readers, these cloth covers were often dyed in bright, eye-catching colours.
One popular pigment was Scheele's green, named after Carl Wilhelm Scheele, a German-Swedish chemist who in 1775 discovered that a vivid green pigment could be produced from copper and arsenic. This dye was not only cheap to make, it was also more vibrant than the copper carbonate greens that had been used for over a century.
Paris green, 's much more durable. It was quickly adopted for use in various items, including book covers, clothing, candles and wallpaper.
These pigments, however, had a significant drawback: they degraded easily, releasing poisonous and carcinogenic arsenic. The frequent reports of green candles poisoning children at Christmas parties, factory workers tasked with applying paint to ornaments convulsing and vomiting green water and warnings of poisonous ball dresses raised serious concerns about the safety of these green dyes.
Part 1

Comment by Dr. Krishna Kumari Challa on Tuesday

Physicists overcome two key operating hurdles in fusion reactions

A team of physicists has devised a way to overcome two key hurdles standing in the way of using fusion as a general power source.

In their paper published in the journal Nature, the group describes how they devised a way to raise the density of the plasma in their reactor while also keeping it stable.

Scientists at various sites around the world have been working for several years to figure out how to use fusion reactions to create electricity for general use—thereby freeing the world from using coal and gas fired power plants that spew greenhouse gases into the atmosphere. But it has been a long and difficult road.

It was just in the past couple of years that researchers were able to show that a fusion reaction could be made to sustain itself, and that more power could be produced than was input into such a system.

The next two hurdles to overcome are increasing the density of the plasma in the reactor and then containing it for extended periods of time—long enough for it to be useful for producing electricity. In this new study, the research team has devised a way to do both in a tokamak chamber.

To contain the plasma as its density was increased, the team used additional magnets and bursts of deuterium where needed. They also allowed for higher densities at the core than near the edges, helping to ensure the plasma could not escape. They held it in that state for 2.2 seconds, long enough to prove that it could be done.

They also found that during that short time span, the average density in the reactor was 20% over the Greenwald limit—a theoretical barrier that had been predicted to mark the point at which adding pressure would escape the magnetic field holding the plasma in place.

They also found that the stability of the plasma was H_98y2 above 1, which means that the experiment was successful.

The research team acknowledges that their experiment was done in a very small reactor—one with a diameter of just 1.6 meters. For such an achievement to be considered fully successful, it will have to be done in a much larger reactor, such as the one currently under construction in France, which will have a diameter of 6.2 meters.

S. Ding et al, A high-density and high-confinement tokamak plasma regime for fusion energy, Nature (2024). DOI: 10.1038/s41586-024-07313-3

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