Comment

Comment by Dr. Krishna Kumari Challa on January 15, 2024 at 8:34am

The Key to Creating Blood Stem Cells May Lie in Your Own Blood

The development of blood stem cells relies on a seemingly unrelated microbe-sensing protein receptor, according to a new study.

The discovery could break new ground in the ongoing quest to produce blood stem cells from a person's own blood – thereby negating the need for bone marrow transplants.

The protein receptor in question, called Nod1, is already known for its role in helping recognize bacterial infections in the body and rallying an immune response, the study's authors note.

But according to their research, Nod1 also seems to serve a different purpose much earlier in life, when an embryo's vascular system is still developing.

The study suggests this microbial sensor helps embryos force some of their vascular endothelial cells to become blood stem cells.

That could be valuable information, given its potential for shedding light on how an embryo makes blood stem cells – and perhaps how we can grow them much later in life, too.

This would eliminate the challenging task of finding compatible bone marrow transplant donors and the complications that occur after receiving a transplant, improving the lives of many leukemia, lymphoma, and anemia patients.

Blood stem cells are progenitors of all white and red cells in our blood, producing all the components of our blood in a process called hematopoiesis.

These blood stem cells, also known as hematopoietic stem cells, arise themselves in the body before birth, developing from endothelial cells within an embryo's aorta.

Part 1

Comment by Dr. Krishna Kumari Challa on January 14, 2024 at 10:42am

First prehistoric people with different syndromes identified from ancient DNA

Researchers  have developed a new technique to measure the number of chromosomes in ancient genomes more precisely, using it to identify the first prehistoric person with mosaic Turner syndrome (characterized by one X chromosome instead of two [XX]), who lived about 2,500 years ago.

As part of their research published in Communications Biology, they also identified the earliest known person with Jacob's syndrome (characterized by an extra Y chromosome—XYY) in the Early Medieval Period, three people with Klinefelter syndrome (characterized by an extra X chromosome—XXY) across a range of time periods, and an infant with Down Syndrome from the Iron Age.

Most cells in the human body have 23 pairs of DNA molecules called chromosomes, and the sex chromosomes are typically XX (female) or XY (male), although there are differences in sexual development. Aneuploidy occurs when a person's cells have an extra or missing chromosome. If this occurs in the sex chromosomes, a few differences like delayed development or changes in height can be seen around puberty.

Ancient DNA samples can erode over time and can be contaminated by DNA from other ancient samples or from people handling them. This makes it difficult to accurately capture differences in the number of sex chromosomes.

The team  of researchers developed a computational method that aims to pick up more variation in sex chromosomes. For the sex chromosomes, it involves counting the number of copies of X and Y chromosomes, and comparing the outcome to a predicted baseline (what you would expect to see).

The team used the new method to analyze ancient DNA from a large dataset of individuals collected as part of their Thousand Ancient British Genomes project across British history, identifying six individuals with aneuploidies across five sites in Somerset, Yorkshire, Oxford and Lincoln (two sites). The individuals lived across a range of time periods, from the Iron Age (2,500 years ago) up to the Post-Medieval Period (about 250 years ago).

They identified five people who had sex chromosomes that fell outside the XX or XY categories. All were buried according to their society's customs, although no possessions were found with them to shed more light on their lives.

The three individuals with Klinefelter syndrome lived across very different time periods, but they shared some similarities—all were slightly taller than average and showed signs of delayed development in puberty.

By investigating details on the bones, the research team could see that it was unlikely that the individual with Turner syndrome had gone through puberty and started menstruation, despite their estimated age of 18-22. Their syndrome was shown to be mosaic; some cells had one copy of chromosome X and some had two.

Through precisely measuring sex chromosomes, they were able to show the first prehistoric evidence of Turner syndrome 2,500 years ago, and the earliest known incidence of Jacob's syndrome around 1,200 years ago. It's hard to see a full picture of how these individuals lived and interacted with their society, as they weren't found with possessions or in unusual graves, but it can allow some insight into how perceptions of gender identity have evolved over time.

 Detection of chromosomal aneuploidy in ancient genomes. Communications Biology, 2024; 7 (1) DOI: 10.1038/s42003-023-05642-z

Comment by Dr. Krishna Kumari Challa on January 13, 2024 at 11:58am

Those types of claims need ridiculously strong evidence to back them up, replicated multiple times over. Chae's paper will no doubt be scrutinized closely by his peers. Nonetheless, it's in findings like this that we might find a way to bridge our gaps in knowledge over gravity's remaining mysteries.

"The evidence for the gravity boost in the low-acceleration regime is now clear enough," Chae writes, "although the scientific community should keep gathering further evidence from future observations."

The study has been published in The Astrophysical Journal.

Part 4

**

Comment by Dr. Krishna Kumari Challa on January 13, 2024 at 11:58am

But binary stars separated by more than 2,000 astronomical units appeared to get a velocity 'boost' at low accelerations, inconsistent with what classical mechanics predicts and regardless of whether hypothetical dark matter was included in the models.

"This gravitational anomaly implies a low-acceleration breakdown of both Newtonian dynamics and general relativity and so has immense implications for astrophysics, cosmology, and fundamental physics," Chae writes in his new paper.

"Thus, one cannot overemphasize the importance of confirming the claimed anomaly from as many independent studies as possible."

While two studies from the same researcher are light-years away from the independent verification theory-overturning results demand, Chae thinks his methods are solid. Although he does admit that theoretical interpretations of the reported anomaly are "wide open."

However, he also makes some big claims in his paper such as "the dark matter paradigm seems now doomed to be abandoned" and that "standard cosmology based on general relativity seems no longer valid, even in principle."

Part 3

Comment by Dr. Krishna Kumari Challa on January 13, 2024 at 11:57am

In a new study, astrophysicist Kyu-Hyun Chae of Sejong University in Korea has analyzed nearly 2,500 wide binary star systems observed by European Space Agency's Gaia space telescope, arriving at the conclusion that standard gravity is breaking down at certain points within them.

Chae first reported finding gravitational anomalies midway through 2023 in a study of the orbital motions of wide binaries, anomalies which he thought represented evidence of one theory of modified gravity, called modified Newtonian dynamics (MOND).

However, some physicists disagreed and instead suggested his sample had been 'contaminated' by pull of undetected close companions in the binary star systems. In other words, the larger-than-expected accelerations Chae observed in some wide binaries were more likely the effect of interlopers lurking in the shadows Chae had missed.

So the Sejong University physicist sought to test his methods again in a smaller, refined subset of 'pure' binary stars. Chae found that closely orbiting twin stars were behaving consistently with classical Newtonian dynamics, so no problems there.

part2

Comment by Dr. Krishna Kumari Challa on January 13, 2024 at 11:56am

Startling Signs of Gravity's Laws Breaking Down Detected in Twin Stars

In 1859, French astronomer and mathematician Urbain Le Verrier detected something strange: Mercury deviated in its dance around the Sun, defying the orderly precession predicted by Newtonian physics.

This odd anomaly couldn't be explained by unknown planets tugging at Mercury's orbit; only by physicist Albert Einstein's 1915 general theory of relativity, which describes how gravity creates curves in the fabric of space-time.

Einstein's general theory has held strong in the century since, but there are a few things about the Universe his mind-bending model can't explain. It breaks down in the centers of black holes and at the dawn of the Universe, for example, and doesn't fit very easily with quantum mechanics, leading some physicists to ponder alternative takes on how gravity works.

While those ideas remain fringe theories, the discovery of gravitational anomalies in widely separated twin stars at infinitesimally low acceleration is once again challenging Einstein's general theory.

Part 1

Comment by Dr. Krishna Kumari Challa on January 13, 2024 at 11:54am

Bizarre Galaxy Discovered With Seemingly No Stars Whatsoever

A newly discovered object is stretching our understanding of what constitutes a galaxy.

Called J0613+52, this massive blob of something some 270 million light-years away appears to have no stars whatsoever. At least, none that can be seen. It's just a haze made of the kind of gas that's found between stars in normal galaxies, drifting around by its lone self .

Its mass and motion appear to be normal for what we'd expect of a spiral galaxy… in fact, if you extracted the stars from a spiral galaxy like the Milky Way or Andromeda, J0613+52 is pretty much what you'd end up with.

According to a team of astronomers  it could be the first discovery of a primordial galaxy in the nearby Universe – a galaxy made up mostly of the gas that formed at the beginning of time.

The object appears to be isolated and undisturbed, having experienced no gravitational interactions over the 13.8 billion-year course that would have disrupted the gas, either tearing it apart, or pushing it into the clumps needed to trigger significant star formation. This makes J0613+52 an object unlike any other we've ever seen before.

It's a galaxy made only out of gas – it has no visible stars. Stars could be there, we just can't see them.

The discovery – one made purely by chance – has been presented at the 243rd meeting of the American Astronomical Society.

Comment by Dr. Krishna Kumari Challa on January 13, 2024 at 10:12am

To rectify this, the same research team has conducted a comprehensive analysis of age-related variations in microRNAs in mice sperm. They compared microRNAs in sperm from mice aged 3, 12, and 20 months and identified the microRNAs that had changed in quantity.

The researchers discovered significant age-associated differences in the microRNAs. Some changes were in microRNAs responsible for regulating the nervous system and genes related to autism spectrum disorder, and these altered microRNAs included those transferred to fertilized eggs.

The present study reveals the potential association between alteration in sperm microRNAs caused by paternal aging, underscoring the significance of investigating the impact of sperm microRNAs on offspring, an aspect that has been relatively overlooked in previous research.

The anticipation is that further exploration of epigenetic factors, specifically microRNAs, will not only contribute to unraveling the pathogenic mechanisms underlying neurodevelopmental disorders but will also offer insights into promoting the health and disease prevention of successive generations.

Kazusa Miyahara et al, Investigating the impact of paternal aging on murine sperm miRNA profiles and their potential link to autism spectrum disorder, Scientific Reports (2023). DOI: 10.1038/s41598-023-47878-z

Part 2

Comment by Dr. Krishna Kumari Challa on January 13, 2024 at 10:10am

Mouse study finds aging sperm affects microRNA, increasing the risk of neurodevelopmental disorders

A recent study has reported that changes in mice sperm microRNAs brought about by aging may affect the growth and development of offspring. The finding adds to the growing literature on the effects of paternal aging on offspring.

Marriages and childbearing later in life are increasingly becoming the norm. While the impacts of maternal age on offspring, such as a higher risk of miscarriage and Down syndrome, are widely understood, the impacts from the paternal side are less so. Yet this is changing.

Recent epidemiological studies have demonstrated that paternal aging exerts a more substantial influence on the heightened risk of neurodevelopmental disorders such as autism spectrum disorder.

A research team has Previously revealed* that epigenetic factors, including histone modifications in spermatogenesis and DNA methylation in mice sperm, undergo changes with age. These alterations might lead to transgenerational effects.

However, the impact of paternal aging on microRNAs (miRNAs), small, non-coding RNA molecules that play a crucial role in regulating gene expression, remains under-explored.

* Misako Tatehana et al. Comprehensive histochemical profiles of histone modification in male germline cells during meiosis and spermiogenesis: Comparison of young and aged testes in mice, PLOS ONE (2020). DOI: 10.1371/journal.pone.0230930

Part 1

Comment by Dr. Krishna Kumari Challa on January 12, 2024 at 11:46am

Even though CO₂ emissions on the whole decrease, significant differences exist between and among biomaterials, necessitating more action to achieve complete climate neutrality across the entire production chain. No material is 100% climate-neutral. Some are close, but others even emit more CO₂ than the fossil materials they replace.

Another consideration is that, despite reducing CO₂ emissions, the production of biomaterials may still cause other environmental impacts. For instance, through the use of fertilizers in the production of biomass used for biomaterials. This can lead to eutrophication: an excess of nutrients resulting in oxygen depletion in surface waters.

The researchers calculated that, on average, the production of biomaterials contributed to an increase in eutrophication impact. Reducing CO2 emissions is very important in mitigating climate change, however, we should avoid shifting the impact to other areas. Extra attention is therefore needed if we decide to transition to biomaterials on a large scale.

Emma A. R. Zuiderveen et al, The potential of emerging bio-based products to reduce environmental impacts, Nature Communications (2023). DOI: 10.1038/s41467-023-43797-9

Part 2

**

• ‹ Previous
• 1
• …
• 247
• 248
• 249
• 250
• 251
• …
• 1042
• Next ›
• Page