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Comment by Dr. Krishna Kumari Challa 2 hours ago

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 2 hours ago

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

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Comment by Dr. Krishna Kumari Challa 2 hours ago

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 2 hours ago

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 3 hours ago

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 3 hours ago

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

Comment by Dr. Krishna Kumari Challa 4 hours ago

Weight-loss drug found to shrink heart muscle in mice and human cells

Trendy weight-loss drugs making headlines for shrinking waistlines may also be shrinking the human heart and other muscles, according to a new  study in JACC: Basic to Translational Science. The authors say the research should serve as a "cautionary tale" about possible long-term health effects of these drugs.

Researchers set out to study why a reported side-effect of the leading weight-loss drug Ozempic is the loss of skeletal muscle.

Ozempic, known medically as semaglutide, was originally designed to help adult patients with type 2 diabetes control their blood sugar. However, this drug—and a host of others in this class of medication—are also being touted for their effectiveness as an anti-obesity medication.

Using mice for the study, the researchers found that heart muscle also decreased in both obese and lean mice. The systemic effect observed in mice was then confirmed in cultured human heart cells.

 Matthew D. Martens et al, Semaglutide Reduces Cardiomyocyte Size and Cardiac Mass in Lean and Obese Mice, JACC: Basic to Translational Science (2024). DOI: 10.1016/j.jacbts.2024.07.006

Comment by Dr. Krishna Kumari Challa 4 hours ago

Scientists discover the molecular composition of potentially deadly venomous fish

New research in FEBS Open Bio reveals insights into the venom of two of the most venomous fish species on Earth: the estuarine stonefish (Synanceia horrida) and the reef stonefish (Synanceia verrucosa), which are typically found in the warm and shallow regions of the Indo-Pacific region, the Persian Gulf, and the Red Sea.

Through multiple analytical techniques, investigators discovered the presence of three neurotransmitters new to stonefish venom, namely gamma-aminobutyric acid (GABA), choline, and 0-acetylcholine.

Although these molecules have been previously found in venoms from other species, such as hornets and spiders, this is the first report of a fish venom that contains GABA, which is capable of modulating cardiovascular function with a range of effects including increased heart rate and low blood pressure.

Characterization of the specific composition of each of these fish species' venom not only provides us with a better understanding of envenomation mechanisms, which are needed for the development of targeted treatments against venom effects, but may also aid in the exploration and development of venom-derived compounds in drug discovery.

Silvia Luiza Saggiomo et al, Interrogating stonefish venom: small molecules present in envenomation caused by Synanceia spp., FEBS Open Bio (2024). DOI: 10.1002/2211-5463.13926

Comment by Dr. Krishna Kumari Challa 4 hours ago

Ethiopian wolves seen feeding on nectar of red hot poker flowers

Strange things happen in nature!

New findings, published in the journal Ecology, describe a newly documented behavior of Ethiopian wolves (Canis simensis).

Researchers observed Ethiopian wolves foraging for the nectar of the Ethiopian red hot poker (Kniphofia foliosa) flower. Some individuals would visit as many as 30 blooms in a single trip, with multiple wolves from different packs exploiting this resource. There is also some evidence of social learning, with juveniles being brought to the flower fields along with adults.

In doing so, the wolves' muzzles become covered in pollen, which they could potentially transfer from flower to flower as they feed. This novel behavior is perhaps the first known plant-pollinator interaction involving a large predator, as well as the only large meat-eating predator ever to be observed feeding on nectar.

Sandra Lai et al, Canids as pollinators? Nectar foraging by Ethiopian wolves may contribute to the pollination of Kniphofia foliosa, Ecology (2024). DOI: 10.1002/ecy.4470

Comment by Dr. Krishna Kumari Challa 4 hours ago

'Flame-Throwing' Guitar Nebula

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