Comment

Comment by Dr. Krishna Kumari Challa on June 27, 2023 at 9:57am

A Hole in the World
There’s a hole under the Indian Ocean. Spanning more than three million square kilometers, the gouge is centered about 1,200 km southwest of the southern tip of India. Because of a low pull of gravity there, combined with higher gravity in surrounding areas, the sea level over the hole is 106 meters lower than the global average, according to a new study.

Why this is cool: Earth is not perfectly round. Rather, it is flatter at the poles and bulges around the equator, with other irregular peaks and valleys caused by different regions’ mass exerting different gravitational pulls. The hole under the Indian Ocean is the planet's most prominent gravitational anomaly.

What the experts say: Slabs of the floor of an ancient sea called the Tethys Ocean which existed 200 million years ago sank into the mantle, creating plumes of molten rock. The hole under the Indian Ocean probably took its present shape about 20 million years ago, when the plumes started to spread within the upper mantle, says Debanjan Pal, a doctoral student at the Indian Institute of Science in Bangalore, and lead author of the new study.

https://eos.org/science-updates/seismologists-search-for-the-indian...

https://www.scientificamerican.com/article/giant-gravity-hole-in-th...

Comment by Dr. Krishna Kumari Challa on June 26, 2023 at 12:54pm

In fact, as far back as 1995, researchers were arguing that babies born with both 'true' and 'pseudo' tails should undergo neuroimaging as well as surgery to make sure their development was tracking like it should.

So why have vestigial tails been reported in case studies since as though they were innocent, undisputed consequences of our genetic heritage?

Part of the problem is that it is not yet known if a true tail is directly derived from the embryonic tail, as some scientists have suggested. There simply isn't enough research on where the congenital abnormality lies – partly because of how rare these case studies are.

Regardless of where a baby's tail came form, however, evidence strongly suggests it is the result of a congenital issue and is not a harmless vestigial trait.

For the life and health of these children, that's an important message that needs to be cleared up once and for all.

Part 3

**

https://www.sciencealert.com/some-babies-are-born-with-tails-but-no...

Comment by Dr. Krishna Kumari Challa on June 26, 2023 at 12:53pm

As it turns out, both rare appendages probably represent an incomplete fusion of the spinal column, or what's known as a spinal dysraphism. This suggests their formation is not a harmless 'regression' in the evolutionary process but a concerning disturbance in an embryo's growth most likely resulting from a mix of genetic and environmental factors.

When a human embryo reaches about five weeks of development, it sprouts a tail-like structure composed of a neural tube and notochord, which is kind of like an early spinal cord.

By the eighth week of development, this tail is typically reabsorbed back into the embryo's body. If it sticks around until birth, it could indicate the presence of a larger birth defect.

In fact, human babies that are born with tails tend to have serious associated neurological defects. In 2008, for instance, a paper argued that "true vestigial tails are not benign" because they may be associated with underlying dysraphism.

Roughly half of the cases reviewed were associated with either meningocele or spina bifida occulta.

This suggests babies born with tails need greater medical attention than a simple surgery. And it strongly disagrees with the 1985 paper that argued "the true human tail is a benign condition not associated with any underlying [spinal] cord malformation."

Part 2

Comment by Dr. Krishna Kumari Challa on June 26, 2023 at 12:52pm

Some Babies Are Born With 'Tails'

 In very rare cases, humans can be born with boneless rear-end appendages, sometimes up to 18 centimeters long. To date, official records have tallied about 40 babies born with 'true tails', consisting of soft, boneless, finger-like protrusions that are easily removed via surgery.

Nevertheless, the rare case studies tend to generate "an unusual amount of interest, excitement and anxiety", according to researchers. Often, this is because the 'tails' are conisidered to be benign, evolutionary remnants of a long lost ancestor.

As it turns out, that's based on an outdated theory that has been contentious for decades now. The reality for these children may be much darker, and they deserve medical attention, not our morbid fascination.

The appendages some babies are born with have historically been deemed 'true' or 'vestigial' tails. But that's a bit of a misnomer, as they aren't really like any other tail known in nature. They typically don't contain bones, cartilage, or a spinal cord. They just kind of hang there without a clear function.

Still, that doesn't mean these appendages are as harmless as scientists used to think.

The misunderstanding over the tail's origin starts with Charles Darwin himself. Over a century ago, Darwin proposed that human vestigial tails are evolutionary accidents, or rudimentary leftovers from a primate ancestor that was once tailed itself.

In the 1980s, scientists took this theory and ran with it. They argued that a genetic mutation, evolved by humans to erase our tails, could sometimes revert back to its ancestral state.

In 1985, a seminal paper defined two different types of 'tails' that human babies can be born with. The first, as mentioned before, is a vestigial or true tail, originally thought to be inherited from our ancestors.

But another type of outgrowth from the tailbone, which sometimes does include bone, is known as a 'pseudotail'.

Historically, the pseudotail has been the one associated with birth defects, and as such, it is not considered vestigial.

Part 1

Comment by Dr. Krishna Kumari Challa on June 26, 2023 at 12:24pm

Understanding Earth gives us the means to better protect it.

Comment by Dr. Krishna Kumari Challa on June 24, 2023 at 10:17am

All the immunity, none of the symptoms, through dietary intervention

Worldwide, more than a million deaths occur each year due to diarrheal diseases that lead to dehydration and malnutrition. Yet, no vaccine exists to fight or prevent these diseases, which are caused by bacteria like certain strains of E. coli. Instead, people with bacterial infections must rely on the body taking one of two defense strategies: kill the intruders or impair the intruders but keep them around. If the body chooses to impair the bacteria, then the disease can occur without the diarrhea, but the infection can still be transmitted—a process called asymptomatic carriage.

Now,  scientists have found that pairing specific diets with disease-causing bacteria can create lasting immunity in mice without the costs of developing sickness, revealing a new potential vaccination strategy. Their findings, published in Science Advances on June 23, 2023, pave the way for the development of new vaccines that could promote immunity for those with diarrheal diseases and possibly other infections.

They  discovered that immunization against diarrheal infections is possible if they allow the bacteria to retain some of its disease-causing behaviour.

Researchers looked at how dietary interventions can create an asymptomatic infection, which they call a cooperative relationship between bacteria and host (the person or animal that the bacteria have infected) where the host does not experience any symptoms. They discovered that an iron-rich diet enabled mice to survive a normally lethal bacterial infection without ever developing signs of sickness or disease.

The high-iron diet increased unabsorbed sugar (glucose) in the mice's intestines, which the bacteria could feast on. The excess sugar served as a "bribe" for the bacteria, keeping them full and incentivized to not attack the host.

This process produced long-term asymptomatic infection with the bacteria, leading the researchers to think that the adaptive immune system (cells and proteins that "remember" infections) may be involved.

Grischa Chen et al, Cooperation between physiological defenses and immune resistance produces asymptomatic carriage of a lethal bacterial pathogen, Science Advances (2023). DOI: 10.1126/sciadv.adg8719. www.science.org/doi/10.1126/sciadv.adg8719

Comment by Dr. Krishna Kumari Challa on June 24, 2023 at 10:00am

Global diabetes cases expected to soar from 529 million to 1.3 billion by 2050

More than half a billion people are living with diabetes worldwide, affecting men, women, and children of all ages in every country, and that number is projected to more than double to 1.3 billion people in the next 30 years, with every country seeing an increase, as published recently in The Lancet.

The latest and most comprehensive calculations show the current global prevalence rate is 6.1%, making diabetes one of the top 10 leading causes of death and disability. At the super-region level, the highest rate is 9.3% in North Africa and the Middle East, and that number is projected to jump to 16.8% by 2050. The rate in Latin America and the Caribbean is projected to increase to 11.3%.

Diabetes was especially evident in people 65 and older in every country and recorded a prevalence rate of more than 20% for that demographic worldwide. The highest rate was 24.4% for those between ages 75 and 79. Examining the data by super-region, North Africa and the Middle East had the highest rate at 39.4% in this age group, while Central Europe, Eastern Europe, and Central Asia had the lowest rate at 19.8%.

Almost all global cases (96%) are type 2 diabetes (T2D); all 16 risk factors studied were associated with T2D. High body mass index (BMI) was the primary risk for T2D—accounting for 52.2% of T2D disability and mortality—followed by dietary risks, environmental/occupational risks, tobacco use, low physical activity, and alcohol use.

Global, regional, and national burden of diabetes from 1990 to 2021, with projections of prevalence to 2050: a systematic analysis for the Global Burden of Disease Study 2021, The Lancet (2023). DOI: 10.1016/S0140-6736(23)01301-6. www.thelancet.com/journals/lan … (23)01301-6/fulltext

**

Comment by Dr. Krishna Kumari Challa on June 23, 2023 at 12:15pm

Y chromosome affects cancer risk

The Y chromosome could be the reason that colorectal and bladder cancers are more aggressive ... and others who carry the chromosome. Researchers have found that the loss of the entire Y chromosome in some cells — which occurs naturally with age — raises the risk of aggressive bladder cancer and could allow bladder tumours to evade detection by the immune system. Separately, scientists identified a Y-chromosome gene in mice that bumps up the risk of some colorectal cancers spreading to other parts of the body by weakening connections between tumour cells. When the gene was deleted, tumour cells became less invasive, and were more likely to be recognized by immune cells. Together, the studies suggest that genetic factors — not just lifestyle — are responsible for the male bias that many cancers have.'

How the Y chromosome makes some cancers more deadly for men

Two studies help to explain why colorectal and bladder tumours take a bigger toll on men than on women.

https://www.nature.com/articles/d41586-023-01987-x?utm_source=Natur...

Comment by Dr. Krishna Kumari Challa on June 23, 2023 at 11:59am

Even 'safe' air pollution levels can harm the developing brain, study finds

Air pollution is known to contribute to disease, which is why regulators such as the Environmental Protection Agency (EPA) set limits on emissions. But mounting evidence suggests that even pollution levels long thought to be safe can increase the risk of health problems, including in the brain.

Now new research  has shown that even levels of certain pollutants considered safe by the EPA are linked to changes in brain function over time. The study, just published in the journal Environment International, used brain scan data from more than 9,000 participants in the Adolescent Brain Cognitive Development (ABCD) study, the largest-ever nationwide study of youth brain health. Children exposed to more pollutants showed changes in connectivity between various brain regions. In some areas, they had more connections than normal; in other areas, they had fewer.

A deviation in any direction from a normal trajectory of brain development—whether brain networks are too connected or not connected enough—could be harmful down the line.

 

Communication between regions of the brain help us navigate virtually every moment of our day, from the way we take in information about our surroundings to how we think and feel. Many of those critical connections develop between the ages of 9 and 12 and can influence whether children experience normal or atypical cognitive and emotional development.

Air quality across the world, even though 'safe' by EPA standards, is contributing to changes in brain networks during this critical time, which may reflect an early biomarker for increased risk for cognitive and emotional problems later in life.

Devyn L. Cotter et al, Effects of ambient fine particulates, nitrogen dioxide, and ozone on maturation of functional brain networks across early adolescence, Environment International (2023). DOI: 10.1016/j.envint.2023.108001

Comment by Dr. Krishna Kumari Challa on June 23, 2023 at 11:41am

Space travel can alter gene expression in white blood cells, weakening our immune system

Evidence is mounting that astronauts are more susceptible to infections while in space. For example, astronauts on board the International Space Station (ISS) commonly suffer from skin rashes, as well as respiratory and non-respiratory diseases. Astronauts are also known to shed more live virus particles; for example, the Epstein-Barr virus, varicella-zoster responsible for shingles, herpes-simplex-1 responsible for sores, and cytomegalovirus. These observations suggest that our immune system might be weakened by space travel. But what could cause such an immune deficit?

New research work shows that the expression of many genes related to immune functions rapidly decreases when astronauts reach space, while the opposite happens when they return to Earth after six months aboard the ISS.

The researchers studied gene expression in leukocytes (white blood cells) in a cohort of 14 astronauts, including three women and 11 men, who had resided on board the ISS for between 4.5 and 6.5 months between 2015 and 2019. Leukocytes were isolated from 4 milliliters blood drawn from each astronaut at 10 time points: once pre-flight, four times in flight, and five times back on Earth.

In total, 15,410 genes were found to be differentially expressed in leukocytes. Among these genes, the researchers identified two clusters, with 247 and 29 genes respectively, which changed their expression in tandem along the studied timeline.

Genes in the first cluster were dialed down when reaching space and back up when returning to Earth, while genes in the second followed the opposite pattern. Both clusters mostly consisted of genes that code for proteins, but with a difference: Their predominant function was related to immunity for the genes in the first cluster, and to cellular structures and functions for the second.

These results suggest that when someone travels to space, these changes in gene expression cause a rapid decrease in the strength of their immune system.

A weaker immunity increases the risk of infectious diseases, limiting astronauts' ability to perform their demanding missions in space. If an infection or an immune-related condition was to evolve to a severe state requiring medical care, astronauts while in space would have limited access to care, medication, or evacuation.

But there is a silver lining to this cloud: The data showed that most genes in either cluster returned to their pre-flight level of expression within one year after return on Earth, and typically much sooner—on average, after a few weeks. These results suggest that returning astronauts run an elevated risk of infection for at least one month after landing back on Earth.

The authors hypothesized that the change in gene expression of leukocytes under microgravity is triggered by "fluid shift," where blood plasma is redistributed from the lower to the upper part of the body, including the lymphatic system. This causes a reduction in plasma volume by between 10% and 15% within the first few days in space. Fluid shift is known to be accompanied by large-scale physiological adaptations, apparently including altered gene expression.

 The transcriptome response of astronaut leukocytes to long missions aboard the International Space Station reveals immune modulation, Frontiers in Immunology (2023). DOI: 10.3389/fimmu.2023.1171103. www.frontiersin.org/articles/1 … mu.2023.1171103/full

• ‹ Previous
• 1
• …
• 363
• 364
• 365
• 366
• 367
• …
• 1080
• Next ›
• Page