Comment

Comment by Dr. Krishna Kumari Challa on November 22, 2024 at 9:09am

Survey shows millions of people hurt by others' drinking, drug use

The risks of alcohol and other drug consumption to the user are well known, but many Americans—nearly 160 million—say they've been harmed by someone else's substance use, according to a new study in the Journal of Studies on Alcohol and Drugs.

In a national survey of U.S. adults, researchers found that 34% said they'd ever suffered "secondhand harm" from someone else's alcohol use—ranging from marriage and family problems to financial fall-out to being assaulted or injured in a drunk-driving accident. Meanwhile, 14% said they'd been harmed by someone else's use of marijuana, opioids or other drugs.

In sheer numbers, that amounts to 113 million Americans who've suffered consequences from another person's drinking, and 46 million who've been hurt by others' drug use. What's more, there was plenty of "overlap" between those two groups: Of survey respondents reporting secondhand harms from alcohol, 30% said they'd also been impacted by other people's drug use. There are more harms than people think.

These habits affect families, relationships and communities.

It makes sense that risky drinking and drug use have far-reaching consequences, but it's only in recent years that research has delved into the secondhand harms of alcohol and drug use. 

 Rosen, E. M. et al.. Prevalence and correlates of alcohol and drug harms to others: Findings from the 2020 U.S. National Alcohol Survey. Journal of Studies on Alcohol and Drugs (2024). DOI: 10.15288/jsad.23-00387

Comment by Dr. Krishna Kumari Challa on November 22, 2024 at 9:02am

Study reveals RNA's unknown role in DNA damage repair

A multi-institutional team of researchers has discovered a previously unknown role for RNA. 

RNA molecules are best known as protein production messengers. They carry genetic instructions from DNA to ribosomes—the factories inside cells that turn amino acids into the proteins necessary for many cell functions. But this study found that RNA can also help cells repair a severe form of DNA damage called a double-strand break, or DSB.

A DSB means both strands of the DNA helix have been severed. Cells have the tools to make some repairs, but a DSB is significant damage—and if not properly fixed can lead to mutations, cell death, or cancer. (Interestingly, cancer treatments, like chemotherapy and radiation, can also cause DSBs.)

When a DSB happens in DNA, it's like a load-bearing beam in a building breaking. A careful, precise repair is needed to ensure the building's—or the DNA's—stability. The pieces must be rejoined accurately to prevent further damage or mutation. Repairing a damaged building requires having a reliable foreman on the job site. A DSB requires something very similar.

A key mechanism the researchers identified is that RNA can help position and hold the broken DNA ends in place, facilitating the repair process.

Specifically, they found that RNA molecules and the broken section of DNA can match up like puzzle pieces. When RNA has this kind of complementarity with the DNA break site, it acts as a scaffold, or a guide, beyond its traditional coding function, showing the cellular machinery where to make repairs. Over millennia, cells have evolved complex mechanisms to fix DSB, each of them functioning like different tools from the same toolbox.

This research work showed that RNA can influence which tools are used, depending on its complementarity to the broken DNA strands. This means that in addition to being the important protein production messenger, RNA acts as both a foreman and laborer when it comes to DNA repair.

A deeper understanding of RNA's role in DNA repair could lead to new strategies for strengthening repair mechanisms in healthy cells, potentially reducing the harmful effects of treatments like chemotherapy and radiation.

 Youngkyu Jeon et al, RNA-mediated double-strand break repair by end-joining mechanisms, Nature Communications (2024). DOI: 10.1038/s41467-024-51457-9

Comment by Dr. Krishna Kumari Challa on November 22, 2024 at 8:20am

Organic geochemical analysis revealed the presence of levoglucosan and significant amounts of retene in the structure's matrix, compounds associated with the combustion of resinous plant materials. Lipid analysis showed straight-chain n-alkanes of odd carbon numbers and n-alkanols of even carbon numbers, biomarkers indicative of fresh leaf wax from plants like rockrose.

Charcoal analysis uncovered partially vitrified remains of Cistaceae, or rockrose family plants, suggesting incomplete combustion under controlled conditions. Less than 10% of the charcoal was from conifer wood.

Palynological examination indicated the presence of abundant pollen grains within the structure, whereas surrounding sediments were free of pollen. This suggests the deliberate introduction of plant materials into the hearth by Neanderthals.

Micromorphological analysis showed no evidence of clay heating above 500°C, indicating that the structure was used for controlled low-temperature processes compatible with tar production.

Carbonate rocks within the structure appear placed intentionally, likely employed to maintain a seal composed of guano and sand. This seal would create a low-oxygen environment essential for effective tar distillation.

To test their hypothesis, the team conducted experimental archaeology by building a similar structure and using it to heat rockrose leaves under low-oxygen conditions. The experiment successfully produced tar sufficient to haft stone spearheads, using only tools and materials available to Neanderthals in the area.
Findings show Neanderthals organized complex fire-related activities by constructing specialized hearths for tar extraction. This confirms a level of cognitive complexity and cultural development previously expected based on their use of manufactured materials.

Juan Ochando et al, A Neanderthal's specialised burning structure compatible with tar obtention, Quaternary Science Reviews (2024). DOI: 10.1016/j.quascirev.2024.109025

Part 2

Comment by Dr. Krishna Kumari Challa on November 22, 2024 at 8:17am

Neanderthal adhesive manufacturing site found in Gibraltar cave

Cut into a Gibraltar cliff face overlooking the Alboran Sea, a cave opening leads back in time to one of the earliest manufacturing sites on the planet—a Neanderthal-built tar distillation oven hidden for 65,000 years.

Researchers have discovered a complex Neanderthal hearth structure in Vanguard Cave. Middle Paleolithic stone artifacts and residues suggest Neanderthals produced tar from rockrose plants (Cistaceae) here, showing off their advanced fire management and technological capabilities.

Neanderthals used fire for warmth, light, cooking, landscape clearing, and extracting adhesive tar from specific plants and trees. Evidence of their use of fire in tar extraction is based on the composition of the tar residues left on tools.
Tar was used as an adhesive for hafting stone tools to wooden handles, representing a significant advancement in tool-making, predating current modern human tar adhesive use by more than 100,000 years.

While the techniques Neanderthals used to extract tar have been previously back-engineered to suggest the use of underground fire pits, direct evidence of these pits has been missing from the record.

In the current study, "A Neanderthal's specialized burning structure compatible with tar obtention," published in Quaternary Science Reviews, researchers analyzed a hearth pit structure in Vanguard Cave, employing geochemical, mineralogical, palynological and micromorphological methods.

They identified a central fire pit with two opposite-sided trenches, revealing a crust of altered rocks and sediment due to prolonged fire use. This structure aligns with theoretical models requiring specialized heating installations for tar production under low-oxygen conditions.

Part 1

Comment by Dr. Krishna Kumari Challa on November 21, 2024 at 11:44am

Cadavers could be bone-marrow donors
A new technique for collecting bone-marrow stem cells from a cadaver’s spinal column could provide transplants for people with blood cancers. A company called Ossium Health is creating a bank of cryopreserved marrow from organ donors with diverse genetic backgrounds. Unlike solid organ donors, a bone-marrow donor must be a very close genetic match to the recipient. This presents a particular challenge when trying to find donors for people from racial minority groups, who are underrepresented in donor registries. The cadaver bank could widen the potential donor pool, although it is still unclear whether the freezing process could damage the stem cells.

https://www.wired.com/story/stem-cell-donation-deceased-ossium-bone...

Comment by Dr. Krishna Kumari Challa on November 21, 2024 at 11:16am

A clue was given in a 1905 paper, which pointed out that acetaldehyde phenylhydrazone was extremely sensitive to acid. Threlfall and his team tried exposing their samples to vapors of acid and ammonia. And they found that exposure to just a tiny bit of one or the other could reliably influence the compound's melting point. The acid acts as a catalyst to speed the shift from the Z to E isomer, lowering the melting point in the process.
If an element or compound can exist in two or more distinct crystalline forms, then each form will have different Gibbs energies and melt at its own distinct temperature.
In this case, the molecules of the crystal are in the cis geometry – of groups pointing towards each other – and melt to an identical geometry in the absence of acid at 100 degrees Celsius. However, in the presence of even a trace of acid, the molecules convert on melting to the trans geometry of groups pointing away from each other. This liquid has a smaller Gibbs energy and is more stable, so the melting point becomes 65 degrees Celsius."

It's similar to the effect salt has on water: adding salt to a pot of water raises the freezing and boiling points. Where it takes a lot of salt to invoke a significant change to water's phase transitions, it takes so little acid to alter acetaldehyde phenylhydrazone that it took more than a century – and Threlfall and his colleagues a decade – to figure it out.

This research is a real testament to human curiosity and tenacity. And it gives us hope for the future. How many more mysteries will be solved in the years stretching into a glittering future of discovery?

https://pubs.acs.org/doi/10.1021/acs.cgd.8b01459

Part 3

**

Comment by Dr. Krishna Kumari Challa on November 21, 2024 at 11:14am

The compound is made by dissolving solid acetaldehyde and adding both liquid phenylhydrazine and aqueous ethanol, and chilling until the mixture freezes and forms solid crystals. To then discover the melting point of the newly formed acetaldehyde phenylhydrazone, you have to re-melt it.

This is where the problems emerged. To understand why acetaldehyde phenylhydrazone melts at two distinct temperatures, the researchers first investigated its solid form. But the most cutting edge probes failed to turn up an answer.

All analyses, performed by Threlfall's team and other recent efforts, failed to find a single difference between acetaldehyde phenylhydrazone samples that melted at the lower temperature, and samples that melted at the higher. These techniques included X-ray diffraction, nuclear magnetic resonance, and IR spectroscopy. As far as scientists could tell, the crystals were identical.
The next step was to investigate the liquid the crystals became after melting.

And there, the researchers got a result. There was a subtle, and temporary, but distinct difference. Although the compounds had the same molecular formula, the structure of the initial melt was slightly different, depending on the temperature.

The compound contains a methyl group that is able to have two distinct configurations, known as the Z isomer and the E isomer.

In its solid phase, the material almost exclusively consists of the Z isomer.

The most stable liquid phase is a mix of about one-third Z isomer to two-thirds E isomer. The lower of the two melting points immediately produces the Z and E mix, while the higher melting point is entirely Z, before switching to part E.
Part 2

Comment by Dr. Krishna Kumari Challa on November 21, 2024 at 11:13am

This Strange Crystal Has Two Melting Points

In 1896, German chemist Emil Fischer noted something very strange about a molecule named acetaldehyde phenylhydrazone. Identical batches of the crystalline compound appeared to have wildly different melting points.

Some batches, he found, melted at temperatures of around 65 degrees Celsius (149 Fahrenheit). Others at 100 degrees Celsius. It was, in a word, utterly bizarre. No other substance was known to behave this way. Nor should it.

According to the laws of thermodynamics that describe the way the physical world behaves, such a result should be impossible.

More than 120 years after Fischer's original discovery, in 2019, an international team of researchers led by chemist Terry Threfall of the University of Southampton in the UK finally found and published the answer. Fischer (who went on to win a 1902 Nobel prize for other work, so he was clearly no quack) had observed something real; but not, as it would turn out, anything that would break thermodynamics.

The culprit? An absolutely miniscule contamination, so small that it is all but undetectable. When acetaldehyde phenylhydrazone melts, it becomes one of two liquids, based on whether the compound has been exposed to a base or an acid. The former appears at the higher melting point; and the latter at the lower.

The observation of such behavior will be exceedingly rare because it depends on the molecules in the crystal and in the liquid having different geometries, which is unusual. Furthermore, it depends also on the conversion by acid being both possible and rapid.

Part 1

Comment by Dr. Krishna Kumari Challa on November 21, 2024 at 10:13am

Healthy women have cells that resemble breast cancer, study finds

A new study from cancer researchers   finds that, in healthy women, some breast cells that otherwise appear normal may contain chromosome abnormalities typically associated with invasive breast cancer. The findings question conventional thinking on the genetic origins of breast cancer, which could influence early cancer detection methods.

The study, published recently in Nature, discovered that at least 3% of normal cells from breast tissue in 49 healthy women contain a gain or loss of chromosomes, a condition known as aneuploidy, and that they expand and accumulate with age. This poses questions for our understanding of "normal" tissues, according to principal investigator of this research.

As researchers continue to develop earlier detection methods using molecular diagnostics along with ductal carcinoma in situ (DCIS) and biopsies, these findings pose a challenge and highlight the potential risk of identifying false positives, as the cells can mistakenly be confused with invasive breast cancer.

A cancer researcher or oncologist seeing the genomic picture of these normal breast tissue cells would classify them as invasive breast cancer.

"We've always been taught that normal cells have 23 pairs of chromosomes, but that appears to be inaccurate because every healthy woman that we analyzed in our study had irregularities, bringing up the very provocative question about when cancer actually occurs", say the researchers.

The study builds upon their previous work on the Human Breast Cell Atlas, which profiled over 714,000 cells to generate a comprehensive genetic map of normal breast tissue at the cellular level.

 Yiyun Lin et al, Normal breast tissues harbour rare populations of aneuploid epithelial cells, Nature (2024). DOI: 10.1038/s41586-024-08129-x

Comment by Dr. Krishna Kumari Challa on November 21, 2024 at 10:07am

Females sleep less and awaken more frequently than males, which may have broad implications for medical research

Females sleep less, wake up more often and get less restorative sleep than males, according to a new animal study by researchers.

The findings, published in the journal Scientific Reports, shed new light on what may underlie sleep differences in men and women and could have broad implications for biomedical research, which for decades has focused primarily on males.

In humans, men and women exhibit distinct sleep patterns, often attributed to lifestyle factors and caregiving roles.  However, these new results suggest that biological factors  may play a more substantial role in driving these sleep differences than previously recognized.

Sleep research has exploded in recent years, with thousands of animal studies exploring how insufficient sleep impacts risk of diseases like diabetes, obesity, Alzheimer's and immune disorders—and how such diseases impact sleep.

But many of those results may have been skewed due to a lack of female representation, the study suggests.

The question the female researchers now ask is: Are we creating too much stress for ourselves because we don't sleep as much as our husband or partner and think our sleep is poor when actually that is a normal sleep profile for ourselves?

The authors hope their findings inspire more research into underlying biological differences. More importantly, they hope the study prompts scientists to re-evaluate how they do research and interpret the results.

Grant S. Mannino et al, The importance of including both sexes in preclinical sleep studies and analyses, Scientific Reports (2024). DOI: 10.1038/s41598-024-70996-1

• ‹ Previous
• 1
• …
• 14
• 15
• 16
• 17
• 18
• …
• 992
• Next ›
• Page