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Comment by Dr. Krishna Kumari Challa on February 23, 2023 at 11:07am

Discovery of massive early galaxies defies prior understanding of the universe

Six massive galaxies discovered in the early universe are upending what scientists previously understood about the origins of galaxies in the universe.

These objects are way more massive than anyone expected. Researchers expected only to find tiny, young, baby galaxies at this point in time, but they've discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe.

Using the first dataset released from NASA's James Webb Space Telescope, the international team of scientists discovered objects as mature as the Milky Way when the universe was only 3% of its current age, about 500-700 million years after the Big Bang. The telescope is equipped with infrared-sensing instruments capable of detecting light that was emitted by the most ancient stars and galaxies. Essentially, the telescope allows scientists to see back in time roughly 13.5 billion years, near the beginning of the universe as we know it.

But scientists think this is their first glimpse back this far, so it's important that they keep an open mind about what they are seeing. While the data indicates they are likely galaxies, they think there is a real possibility that a few of these objects turn out to be obscured supermassive black holes. Regardless, the amount of mass they discovered means that the known mass in stars at this period of our universe is up to 100 times greater than they had previously thought. Even if they cut the sample in half, this is still an astounding change.

In a paper published recently (Feb. 22) in Nature, the researchers show evidence that the six galaxies are far more massive than anyone expected and call into question what scientists previously understood about galaxy formation at the very beginning of the universe.

The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science. Scientists have been informally calling these objects 'universe breakers'—and they have been living up to their name so far.

 Accounting for such a high amount of mass would require either altering the models for cosmology or revising the scientific understanding of galaxy formation in the early universe—that galaxies started as small clouds of stars and dust that gradually grew larger over time. Either scenario requires a fundamental shift in our understanding of how the universe came to be.

One way to confirm the team's finding and alleviate any remaining concerns would be to take a spectrum image of the massive galaxies. That would provide the team data on the true distances, and also the gasses and other elements that made up the galaxies. The team could then use the data to model a clearer of picture of what the galaxies looked like, and how massive they truly were. A spectrum will immediately tell us whether or not these things are real. 

 Ivo Labbe, A population of red candidate massive galaxies ~600 Myr after the Big Bang, Nature (2023). DOI: 10.1038/s41586-023-05786-2. www.nature.com/articles/s41586-023-05786-2

Comment by Dr. Krishna Kumari Challa on February 22, 2023 at 11:29am

Although the effects of senescence may seem paradoxical at first sight, recent studies show that it is all a question of temporality... and context. "In the short term, the secretome is involved in recruiting immune cells to eliminate tumor cells. But in the long term, the accumulation of senescent cells can promote the destruction of the extracellular matrix—which allows the organization of cells into tissue—and the proliferation of malignant cells." The researchers wondered whether there was senescence in glioblastoma and, if so, what role it might play in the cancer progression. To do this, they investigated both an animal model of glioblastoma and tumor tissue removed from patients during surgery. The team first examined 28 patient tumors. They found, in varying proportions (0.4% to 7% of the original mass of glioblastoma), senescent cells of different cell types—tumoral, immune, or glial—located mainly in areas of malignant cell proliferation, as well as in necrosis zones. In mice, suppressing a part of the senescent tumor cells made it possible to modify the immune activity within the tumor and extend the animal's lifespan. The researchers then defined a characteristic signature of senescence based on the expression of 31 genes in mice and ensured that it was identical in humans. Researchers observed that the strong expression of this signature was associated with a poor prognosis. This shows the pro-tumor action of senescence in glioblastoma. Modulating cellular senescence could therefore constitute a new therapeutic avenue to be combined with conventional treatments—to increase their effectiveness.

Rana Salam et al, Cellular senescence in malignant cells promotes tumor progression in mouse and patient Glioblastoma, Nature Communications (2023). DOI: 10.1038/s41467-023-36124-9

Part 2

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Comment by Dr. Krishna Kumari Challa on February 22, 2023 at 11:27am

Cellular senescence plays a significant role in cerebral tumours

Glioblastomas are the most common malignant tumors of the adult brain. They resist conventional treatment, including surgery, followed by radiation therapy and chemotherapy. Despite this armamentarium, glioblastomas inexorably recur.

In a new study published in Nature Communications, researchers have shown that the elimination of senescent cells, i.e., cells that have stopped dividing, can modify the tumor ecosystem and slow its progression. These results open up new avenues for treatment.

Glioblastoma, the most common adult brain cancer, affects 2 to 5 in 100,000 individuals. While the incidence of the disease is highest in those between 55 and 85 years old, it is increasing in all age groups. This effect can't be attributed to improved diagnostic techniques alone, suggesting the influence of environmental factors hitherto unidentified.

People with the disease have a median survival of 15 months after diagnosis, as the tumor infiltrates the brain very quickly. There is an urgent need to better understand the biology of the tumor, including the diversity of cell types of which it is composed, and their role. The challenge is to find new therapeutic targets and significantly increase the lifespan of patients.

Finding the weak spot of glioblastoma is no easy task. One recent approach consists in targeting a key biological process: cellular senescence. Initially identified during the normal aging of cells, it corresponds to the loss of their ability to divide. Interruption of the cell cycle has an advantage: it prevents the uncontrolled division of malignant cells. In that case, senescence contributes to the body's anti-tumor response.

Long considered a simple marker of aging, we now know that senescence occurs throughout life, especially in response to genotoxic stress—that is, an event that disrupts or damages DNA, such as chemotherapy

When cells enter senescence, they secrete various molecules. This is called the senescence-associated secretory phenotype—or secretome. The secretome can influence the cellular environment in a beneficial or detrimental way. For example, it can activate the immune system or, conversely, induce the formation of blood vessels that contribute to the irrigation of the cancerous tissue. It all depends on the molecules secreted.

Part 1

Comment by Dr. Krishna Kumari Challa on February 22, 2023 at 11:09am

Physicists create new model of ringing black holes

When two black holes collide into each other to form a new bigger black hole, they violently roil spacetime around them, sending ripples, called gravitational waves, outward in all directions. Previous studies of black hole collisions modeled the behavior of the gravitational waves using what is known as linear math, which means that the gravitational waves rippling outward did not influence, or interact, with each other. Now, a new analysis has modeled the same collisions in more detail and revealed so-called nonlinear effects.

Nonlinear effects are what happens when waves on the beach crest and crash. The waves interact and influence each other rather than ride along by themselves. With something as violent as a black hole merger, researchers expected these effects but had not seen them in their models until now. New methods for extracting the waveforms from their simulations have made it possible to see the nonlinearities.

In the future, the new model can be used to learn more about the actual black hole collisions that have been routinely observed by LIGO (Laser Interferometer Gravitational-wave Observatory) ever since it made history in 2015 with the first direct detection of gravitational waves from space. LIGO will turn back on later this year after getting a set of upgrades that will make the detectors even more sensitive to gravitational waves. Supercomputers are needed to carry out an accurate calculation of the entire signal: the inspiral of the two orbiting black holes, their merger, and the settling down to a single quiescent remnant black hole.

Keefe Mitman et al, Nonlinearities in black hole ringdowns, Physical Review Letters (2023). Accepted for publication: journals.aps.org/prl/accepted/ … 5c5aaa672c0e199adcff. On Arxiv: DOI: 10.48550/arxiv.2208.07380

Comment by Dr. Krishna Kumari Challa on February 21, 2023 at 11:39am

Indian women face fieldwork challenges

Female researchers face challenges participating in fieldwork in India — from trained local residents refusing to work with women to objections from family members over travel, prejudices surrounding the type of work considered appropriate for women, and a lack of role models. Although the extent of the effect is hard to measure, women in the country are under-represented in fields that require extensive fieldwork such as geology, evolutionary biology and environmental studies. “Changing that image of what a scientist and a field researcher should look like, should be the first step. Let’s start there,” says evolutionary biologist Ashwini Mohan.

https://www.rukhmabai.com/despite-progress-fieldwork-remains-a-stum...

Comment by Dr. Krishna Kumari Challa on February 21, 2023 at 10:49am

Scientists make stunning discovery, find new protein activity in telomeres

Once thought incapable of encoding proteins due to their simple monotonous repetitions of DNA, tiny telomeres at the tips of our chromosomes seem to hold a potent biological function that's potentially relevant to our understanding of cancer and aging.

Reporting in the Proceedings of the National Academy of Sciences

researchers made the stunning discovery that telomeres contain genetic information to produce two small proteins, one of which they found is elevated in some human cancer cells, as well as cells from patients suffering from telomere-related defects.

Based on this research, they think simple blood tests for these proteins could provide a valuable screen for certain cancers and other human diseases. These tests also could provide a measure of 'telomere health,' because we know telomeres shorten with age.

Telomeres contain a unique DNA sequence consisting of endless repeats of TTAGGG bases that somehow inhibit chromosomes from sticking to each other. Two decades ago, researchers showed that the end of a telomere's DNA loops back on itself to form a tiny circle, thus hiding the end and blocking chromosome-to-chromosome fusions. When cells divide, telomeres shorten, eventually becoming so short that the cell can no longer divide properly, leading to cell death.

Scientist first identified telomeres about 80 years ago, and because of their monotonous sequence, the established dogma in the field held that telomeres could not encode for any proteins, let alone ones with potent biological function.

Researchers now conducted experiments—as described in the PNAS paper—to show how telomeric DNA can instruct the cell to produce signaling proteins they termed VR (valine-arginine) and GL (glycine-leucine). Signaling proteins are essentially chemicals that trigger a chain reaction of other proteins inside cells that then lead to a biological function important for health or disease.

They then chemically synthesized VR and GL to examine their properties using powerful electron and confocal microscopes along with state-of-the-art biological methods, revealing that the VR protein is present in elevated amounts in some human cancer cells, as well as cells from patients suffering from diseases resulting from defective telomeres.

It is it's possible that as we age, the amount of VR and GL in our blood will steadily rise, potentially providing a new biomarker for biological age as contrasted to chronological age. Scientists think inflammation may also trigger the production of these proteins.

 Al-Turki, Taghreed M. et al, Mammalian telomeric RNA (TERRA) can be translated to produce valine–arginine and glycine–leucine dipeptide repeat proteins, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2221529120

Comment by Dr. Krishna Kumari Challa on February 21, 2023 at 10:38am

Experts discover how zebra stripes work to thwart horsefly attacks

According to this new discovery, stark black-white distinctions and small dark patches are particularly effective in thwarting horsefly attack. These characteristics specifically eliminate the outline of large monochrome dark patches that are attractive to horseflies at close distances.

 A team of researchers theorized that the thin back stripes serve to minimize the size of local features on a zebra that are appealing to the biting flies.

We knew that horseflies are averse to landing on striped objects—a number of studies have now shown this, but it is not clear which aspects of stripes they find aversive. Is it the thinness of the stripes? The contrast of black and white? The polarized signal that can be given off objects? So researchers  set out to explore these issues using different patterned cloths draped over horses and filmed incoming horseflies. 

The team found that tabanid horseflies are attracted to large dark objects in their environment but less to dark broken patterns. All-gray coats were associated with by far the most landings, followed by coats with large black triangles placed in different positions, then small checkerboard patterns in no particular order. In another experiment, they found contrasting stripes attracted few flies whereas more homogeneous stripes were more attractive.

This suggests that any hoofed animal that reduces its overall dark outline against the sky will benefit in terms of reduced ectoparasite attack.

Tim Caro et al, Why don't horseflies land on zebras?, Journal of Experimental Biology (2023). DOI: 10.1242/jeb.244778

Comment by Dr. Krishna Kumari Challa on February 21, 2023 at 10:21am

Weaponizing part of the SARS-CoV-2 spike protein against itself to prevent infection

The virus that causes COVID-19, called SARS-CoV-2, uses its spike protein in order to stick to and infect our cells. The final step for the virus to enter our cells is for part of its spike protein to act like a twist tie, forcing the host cell's outer membrane to fuse with the virus.

Now researchers have generated a molecule based on the twisted part of the spike protein (called HR2), which sticks itself onto the virus and prevents the spike protein from twisting. The reason the longHR2_42 inhibitor may work against an evolving virus is that it is based on part of the spike protein that hasn't changed even as other parts have.

Kailu Yang et al, Nanomolar inhibition of SARS-CoV-2 infection by an unmodified peptide targeting the prehairpin intermediate of the spike protein, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2210990119

Conference: www.biophysics.org/2023meeting#/

Comment by Dr. Krishna Kumari Challa on February 21, 2023 at 10:17am

A robot that can help firefighters during indoor emergencies

Robots could be valuable assistants for most first responders, as they could help them to remotely monitor or intervene in areas that are inaccessible or life-threatening for humans. Firefighters, who are at high risk of getting injured during their missions, would undoubtedly benefit from the assistance of reliable mobile robots.

Researchers recently created an autonomous ground robot that could assist firefighters when they are tackling emergencies in indoor environments. Their system, introduced in the Journal of Field Robotics, could allow agents responding to fire emergencies to plan their interventions better, clearing safe paths for them to access affected areas and supporting them during evacuations.

This work is part of a project called HelpResponder, which aims to reduce the accident rates and mission times of intervention teams This is achieved using fixed beacons, drones, and ground robots. This new robot can monitor its surrounding environment, sharing the data it collects with human agents. This is achieved using various sensors that can measure the temperature, humidity and air quality in an indoor setting, as well as its position and the position of other objects. This data is then saved in a database that can be remotely accessed by firefighters through a smartphone application. 

N. Fernández Talavera et al, An autonomous ground robot to support firefighters' interventions in indoor emergencies, Journal of Field Robotics (2023). DOI: 10.1002/rob.22150

M. Cristina Rodriguez-Sanchez et al, HelpResponder—System for the Security of First Responder Interventions, Sensors (2021). DOI: 10.3390/s21082614

Fernández Talavera, Sistema de navegación autónomo en entornos reales y simulados para situaciones de emergencia, BURJC Digital (2021). hdl.handle.net/10115/18048

Survey of fire victims in Spain. Fundacion MAPFRE(2021). www.fundacionmapfre.org/en/pub … -fire-in-spain-2014/

Juan Jesús Roldán-Gómez et al, A Survey on Robotic Technologies for Forest Firefighting: Applying Drone Swarms to Improve Firefighters' Efficiency and Safety, Applied Sciences (2021). DOI: 10.3390/app11010363

Comment by Dr. Krishna Kumari Challa on February 20, 2023 at 11:14am

This old pic of evolution  is  misleading and incomplete. The problem with this old image is that first,  it suggests a linear progression. The second is that it suggests that we are descendants of chimpanzees. And the third is that early Homo sapiens were not white – it’s actually a pretty recent phenomenon, around 7,500–8,500 BCE in Europe.

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