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Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 9:20am

The researchers added these fast-joining RNA bases into a watery solution, provided an energy source and examined the length of the RNA molecules that formed. Their findings were sobering, as the resulting strands of up to five base pairs only survived for a matter of minutes.

The results were different, however, when the researchers started by adding short strands of pre-formed RNA. The free complementary bases quickly joined with this RNA in a process called hybridization. Double strands of three to five base pairs in length formed and remained stable for several hours.

The exciting part is that double strands lead to RNA folding, which can make the RNA catalytically active.

Double-stranded RNA therefore has two advantages: it has an extended lifespan in the primordial soup and serves as the basis for catalytically active RNA.

Another characteristic of double-stranded RNA could have helped bring about the origin of life. It is firstly important to note that RNA molecules can also form protocells. These are tiny droplets with an interior fully separated from the outside world. Yet, these protocells do not have a stable cell membrane and so easily merge with other protocells, which causes their contents to mix.

This is not conducive to evolution because it prevents individual protocells from developing a unique identity. However, if the borders of these protocells are composed of double-stranded DNA, the cells become more stable and merging is inhibited.

Christine M. E. Kriebisch et al, Template-based copying in chemically fuelled dynamic combinatorial libraries, Nature Chemistry (2024). DOI: 10.1038/s41557-024-01570-5

Part 2

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Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 9:17am

Researchers demonstrate mechanism that may have stabilized the first RNA molecules

The origins of life remain a major mystery. How were complex molecules able to form and remain intact for prolonged periods without disintegrating? A team at ORIGINS, a Munich-based Cluster of Excellence, has demonstrated a mechanism that could have enabled the first RNA molecules to stabilize in the primordial soup.

When two RNA strands combine, their stability and lifespan increase significantly. The work is published in the journal Nature Chemistry.

In all likelihood, life on Earth began in water, perhaps in a tide pool that was cut off from seawater at low tide but flooded by waves at high tide. Over billions of years, complex molecules like DNA, RNA and proteins formed in this setting before, ultimately, the first cells emerged. 

RNA is a fascinating molecule. It can store information and also catalyze biochemical reactions. Scientists therefore think that RNA must have been the first of all complex molecules to form.

The problem, however, is that active RNA molecules are composed of hundreds or even thousands of bases and are very unstable. When immersed in water, RNA strands quickly break down into their constituent parts—a process known as hydrolysis. So, how could RNA have survived in the primordial soup?

In laboratory testing, the researchers from TUM and LMU used a model system of RNA bases that join together more easily than naturally occurring bases in our cells today.

Part 1

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 8:39am

Scientists pin down the origins of the moon's tenuous atmosphere

While the moon lacks any breathable air, it does host a barely-there atmosphere. Since the 1980s, astronomers have observed a very thin layer of atoms bouncing over the moon's surface. This delicate atmosphere—technically known as an "exosphere"—is likely a product of some kind of space weathering. But exactly what those processes might be has been difficult to understand with any certainty.

Now, scientists  say they have identified the main process that formed the moon's atmosphere and continues to sustain it today. In a study appearing in Science Advances, the team reports that the lunar atmosphere is primarily a product of "impact vaporization."

In their study, the researchers analyzed samples of lunar soil collected by astronauts during NASA's Apollo missions.

Their analysis suggests that over the moon's 4.5-billion-year history its surface has been continuously bombarded, first by massive meteorites, then more recently, by smaller, dust-sized "micrometeoroids."

These constant impacts have kicked up the lunar soil, vaporizing certain atoms on contact and lofting the particles into the air. Some atoms are ejected into space, while others remain suspended over the moon, forming a tenuous atmosphere that is constantly replenished as meteorites continue to pelt the surface.

The researchers found that impact vaporization is the main process by which the moon has generated and sustained its extremely thin atmosphere over billions of years.

Nicole Nie, Lunar Soil Record of Atmosphere Loss over Eons, Science Advances (2024). DOI: 10.1126/sciadv.adm7074. www.science.org/doi/10.1126/sciadv.adm7074

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 8:26am

To examine the role of context in driving brain coupling, the team collected brain activity data and conversation transcripts from pairs of epilepsy patients during natural conversations.

The patients were undergoing intracranial monitoring using electrocorticography for unrelated clinical purposes at the New York University School of Medicine Comprehensive Epilepsy Center. Compared to less invasive methods like fMRI, electrocorticography records extremely high-resolution brain activity because electrodes are placed in direct contact with the surface of the brain.

Next, the researchers used the large language model GPT-2 to extract the context surrounding each of the words used in the conversations, and then used this information to train a model to predict how brain activity changes as information flows from speaker to listener during conversation.

Using the model, the researchers were able to observe brain activity associated with the context-specific meaning of words in the brains of both speaker and listener.

They showed that word-specific brain activity peaked in the speaker's brain around 250 ms before they spoke each word, and corresponding spikes in brain activity associated with the same words appeared in the listener's brain approximately 250 ms after they heard them.

Compared to previous work on speaker–listener brain coupling, the team's context-based approach model was better able to predict shared patterns in brain activity. This shows just how important context is, because it best explains the brain data. Large language models take all these different elements of linguistics like syntax and semantics and represent them in a single high-dimensional vector. This work shows that this type of unified model is able to outperform other hand-engineered models from linguistics.

A shared model-based linguistic space for transmitting our thoughts from brain to brain in natural conversations, Neuron (2024). DOI: 10.1016/j.neuron.2024.06.025. www.cell.com/neuron/fulltext/S0896-6273(24)00460-4

Part 2

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 8:24am

Brain activity associated with specific words is mirrored between speaker and listener during a conversation

When two people interact, their brain activity becomes synchronized, but it was unclear until now to what extent this "brain-to-brain coupling" is due to linguistic information or other factors, such as body language or tone of voice.

Researchers report August 2 in the journal Neuron that brain-to-brain coupling during conversation can be modeled by considering the words used during that conversation, and the context in which they are used.

Researchers could see linguistic content emerge word-by-word in the speaker's brain before they actually articulate what they're trying to say, and the same linguistic content rapidly reemerges in the listener's brain after they hear it.

To communicate verbally, we must agree on the definitions of different words, but these definitions can change depending on the context. For example, without context, it would be impossible to know whether the word "cold" refers to temperature, a personality trait, or a respiratory infection.

The contextual meaning of words as they occur in a particular sentence, or in a particular conversation, is really important for the way that we understand each other.

Part 1

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 6:48am

A bio-inspired vision sensor that can detect spectrally distinctive features

The ability to detect objects in settings with unfavorable lighting, for example at night, in shadowed locations or in foggy conditions, could greatly improve the reliability of autonomous vehicles and mobile robotic systems. Most widely employed computer vision methods, however, have been found to perform under poor lighting.

Researchers  recently introduced a new bio-inspired vision sensor that can adapt to the spectral features of the environments it captures, thus successfully detecting objects in a wider range of lighting conditions. This newly developed sensor, introduced in a paper published in Nature Electronics, is based on an array of photodiodes arranged back-to-back.

The primary objective of this recent work was to design a vision sensor that is better than other sensors at recognizing objects in an environment marked by strong light interference and when there is smoke or fog in the air. The sensor they planned to develop would also collect data with minimal time latency, consuming very little power.

Bangsen Ouyang et al, Bioinspired in-sensor spectral adaptation for perceiving spectrally distinctive features, Nature Electronics (2024). DOI: 10.1038/s41928-024-01208-x.

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 6:37am

Why editing the knowledge of LLMs post-training can create messy ripple effects

After the advent of ChatGPT, the readily available model developed by Open AI, large language models (LLMs) have become increasingly widespread, with many online users now accessing them daily to quickly get answers to their queries, source information or produce customized texts. Despite their striking ability to rapidly define words and generate written texts pertinent to a user's queries, the answers given by these models are not always accurate and reliable.

In addition, the knowledge available worldwide is in constant evolution. Thus, these models can sometimes report outdated information that they were fed during training, as opposed to other relevant and up-to-date information released after their training. To overcome this limitation of LLMs and increase the reliability of their answers, some computer scientists have been exploring the possibility of editing their knowledge base after they have completed their training.

These knowledge editing (KE) interventions should then influence all the content produced by an LLM, creating a ripple effect. This means that all the model's future answers about a given topic should reflect the new information it acquired about this topic after its knowledge was altered.

Unfortunately, studies suggest that these ripple effects do not always take place. In essence, this means that while a model might be able to correctly answer direct questions about altered information, it might not encompass the new knowledge it acquired in all of the answers it generates, including those that indirectly touch on the new information.

Researchers at University of Illinois Urbana-Champaign recently set out to better understand the processes underlying the successful realization of ripple effects following the editing of LLM knowledge. Their paper, published on the arXiv preprint server, could inform future efforts aimed at updating the knowledge of these widely used models, thus contributing to the improvement of these models post-training.

 Jiaxin Qin et al, Why Does New Knowledge Create Messy Ripple Effects in LLMs?, arXiv (2024). DOI: 10.48550/arxiv.2407.12828

Comment by Dr. Krishna Kumari Challa on August 2, 2024 at 12:18pm

Female participants who ate a diet rich in vitamins, minerals, and antioxidants, for instance, had cells with the 'youngest'-looking epigenetic age. Those on the Mediterranean diet were observed to have the slowest epigenetic clocks.

Still, the more added sugar a person consumed each day, the older their salivary DNA appeared to scientists, even when their meals were rich in foods that maintain and repair DNA.

This was true even when accounting for education, lifestyle factors, and the current health of participants.

On average, women in the study ate just over 60 grams of sugar a day, although some ate more than 300 grams a day.
The findings suggest that added sugar can significantly accelerate cellular aging, but it is important to note that this study is only based on food records collected over three non-consecutive days, and one salivary swab.

Previous studies have suggested that cells can appear epigenetically 'younger' or 'older' depending on when in the day their DNA was sampled, so longer term studies among both sexes are needed before further conclusions can be drawn.

https://jamanetwork.com/journals/jamanetworkopen/article-abstract/2...

Part 2

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Comment by Dr. Krishna Kumari Challa on August 2, 2024 at 12:16pm

Added Sugar in Your Diet May Speed Up Your Body's Biological Aging

Eating large amounts of food with added sugar could have a hyperactive effect on the body's ticking biological clock, even when the rest of a person's diet remains otherwise healthy.

A new study among 342 Black and White middle-aged women (please note that the sample size is very low) has found those who eat high quantities of added sugar have 'older-looking' cells.

The findings could help explain why some people seem to age faster or slower than others who have lived the same number of years. Sugar intake could be an important, overlooked factor.

Along with the occasional mutation, our DNA can accumulate less permanent edits over time. These so-called epigenetic changes often act like chemical padlocks, deactivating genes and altering how the body's genetic code is expressed for a time.
A collection of transient edits is referred to as an epigenetic clock, and can be a useful way to guess at a person's true biological age. Epigenetic changes can be read by scientists to better understand how old a cell is and what damages or stresses it has experienced.

Diet, lifestyle, genetics, and disease are all known to affect how quickly a person's epigenetic clock ticks, but this is one of the first studies to examine how sugar specifically plays a role. It also includes a diverse cohort.

The findings suggest that added sugar can alter epigenetic switches related to aging more quickly than healthier foods can turn them off, regardless of whether healthy nutrients are also present.

Part 1

Comment by Dr. Krishna Kumari Challa on August 2, 2024 at 12:12pm

Almost Half of Dementia Cases Avoidable by Addressing 14 Risk Factors, Major Study Finds

Millions of cases of dementia could be prevented or delayed by reducing a range of risk factors according to a major new study, though outside experts warn that such measures can only go so far.

The debilitating condition, which progressively robs people of their memories, cognitive abilities, language and independence, currently affects more than 55 million people across the world. Dementia is caused by a range of diseases, the most common of which is Alzheimer's.

A huge review of the available evidence published in The Lancet journal on Wednesday said that the "potential for prevention is high" in the fight against dementia.

The study follows a previous report in 2020 that also emphasised the importance of prevention.

At the time, the international team of researchers estimated that 40 percent of dementia cases were linked to 12 risk factors.

The factors included people having a lower level of education, hearing problems, high blood pressure, smoking, obesity,  depression physical inactivity,  diabetes, excessive drinking, traumatic brain injury, air pollution and social isolation.

The latest update adds two more risk factors: vision loss and high cholesterol.

"Nearly half of dementias could theoretically be prevented by eliminating these 14 risk factors," the study said.

https://www.thelancet.com/journals/lanhl/article/PIIS2666-7568(24)00117-X/fulltext

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