Knowledge Update

New York, June 21 (IANS) High blood sugar for long periods can cause serious health problems but surprisingly it can have a protective effect against one type of brain tumour that is not cancerous, says a new study.

"It's so unexpected. Usually diabetes and high blood sugar raises the risk of cancer, and it's the opposite here," said lead researcher Judith Schwartzbaum, Associate Professor at Ohio State University. 

The discovery could shed light on the development of meningiomas -- tumours arising from the brain and spinal cord that are usually not cancerous but that can require risky surgery and affect a patient's quality of life.

When the researchers compared blood tests in a group of more than 41,000 Swedes with meningioma diagnoses, they found that high blood sugar, particularly in women, actually meant the person was less likely to face a brain tumour diagnosis.

"It should lead to a better understanding of what's causing these tumors and what can be done to prevent them," Schwartzbaum noted.

Though meningiomas are rarely cancerous, they behave in a similar way, leading scientists to wonder if some relationships between possible risk factors and tumour development would be similar, Schwartzbaum said.

The researchers, looking at data collected from 1985 to 2012, identified 296 cases of meningioma, more than 61 percent of them in women.

Women with the highest fasting blood sugar were less than half as likely as those with the lowest readings to develop a tumour.

The study was published in the British Journal of Cancer.

Possible explanations for the relationship could be found by closer examination of the role of sex hormones and the interplay between glucose levels and those hormones, Schwartzbaum said. 

It's also possible that sugar levels dip during early tumour development because the tumour is using glucose to grow, she said.

A diabetes diagnosis before meningioma also appeared to decrease the risk of this tumour, although Schwartzbaum said the data likely had incomplete information on diabetes.​

​New York, June 21 (IANS) DNA tests have confirmed that the earliest population to settle in the high valleys of the Himalayas were indeed East Asians of high altitude origin.

The genetic make-up of high-altitude Himalayan populations has remained remarkably stable despite cultural transitions and exposure to outside populations through trade, the findings showed.

"In this study, we demonstrate that the Himalayan mountain region was colonised by East Asians of high altitude origin, followed by millennia of genetic stability despite marked changes in material culture and mortuary behaviour," said senior author of the study Christina Warinner, Professor at the University of Oklahoma in the US.

The study was published in the journal Proceedings of the National Academy of Sciences.

The high altitude transverse valleys of the Himalayas were among the last habitable places permanently colonised by prehistoric humans due to the challenges of resource scarcity, cold stress and hypoxia.

The modern populations of these valleys, who share cultural and linguistic affinities with peoples found today on the Tibetan plateau, were commonly assumed to be the descendants of the earliest inhabitants of the Himalayan arc. 

However, this assumption had been challenged by archaeological and osteological evidence suggesting these valleys may have been originally populated from areas other than the Tibetan plateau, including those at low elevation.

To address the problem, Warinner and colleagues sequenced the nuclear and mitochondrial genomes of eight high-altitude Himalayan individuals dating to three distinct cultural periods spanning 3,150 to 1,250 years before present. 

The authors compared these ancient DNA sequences to genetic data from diverse modern humans, including four Sherpa and two Tibetans from Nepal.

All eight prehistoric individuals across the three time periods were most closely related to contemporary highland East Asian populations -- the Sherpas and Tibetans.

The findings strengthen the evidence that the diverse material culture of prehistoric Himalayan populations is the result of acculturation or culture diffusion rather than large-scale gene flow or population replacement from outside highland East Asia.​

​New York, June 20 (IANS) Babies who are born through Caesarean, exposed to antibiotics and are fed on formula milk are likely to have a slow growth as well as a decline in the diversity of microbes throughout the first year of life, finds a new study.

The findings showed that such children were at an increased risk of developing asthma, autoimmune diseases and obesity. 

Compared to vaginally born infants, those delivered by C-section showed significantly greater diversity of species in the weeks after birth. 

However, these measures declined in cesarean-born infants during their first month, after which they displayed lower diversity up to two years of age. 

"Our results provide evidence that modern practices have changed a baby's microbial communities in ways that last through the first year," said Martin Blaser, Professor at New York University.

"The change in birth mode interrupted the natural interplay between diversity and dominance," Blaser added.

Further, antibiotic treatment also significantly diminished diversity of bacterial species immediately following birth. 

Children fed on formula milk showed a decrease in the diversity of species during the second year of life also.

The study, published in the journal Science Translational Medicine, focused on the microbiome, the mix of bacterial species that live on human skin and in our guts and that co-evolved with humans to play roles in digestion, metabolism and immunity.

The team assessed the effects of modern practices on intestinal microbiota development in 43 US children of these 24 of were born by vaginal delivery and 19 by C-section.

They then used genomic and statistical techniques to analyse the millions of pieces of bacterial DNA in the samples.​

New York, June 20 (IANS) People who tend to put things off are more likely to develop insomnia -- a sleep disorder characterised by difficulty in falling or staying asleep, says a study.

The researchers said the link between procrastination and trouble falling asleep seemed to be explained by people worrying about things that they wanted to get done before going to bed, Live Science reported.

At bedtime "people who procrastinate are ruminating about the things they need to do and haven't done" and that makes it difficult for them to go to sleep, study author Ilana Hairston from Academic College of Tel Aviv in Israel was quoted as saying.

The study involved nearly 600 people. Through online questionnaires, the researchers examined their tendencies to procrastinate, along with their sleep problems and emotional states. 

The researchers found that trouble sleeping in participants could be an outcome of procrastination.

The results of the study will be published in a forthcoming issue of the journal Personality and Individual Differences.

Another important dimension that the researchers uncovered in the study was hat morning people -- those who wake up early in the morning and go to be early in the evening -- reported lower levels of procrastination and fewer sleep problems, compared to those who go to sleep late at night and wake up late -- the evening people.

The finding that evening people tend to procrastinate more than morning people is consistent with previous research, the researchers said.​

​London, June 20 (IANS) Scientists have discovered unexpectedly high number of giant exoplanets in a cluster of stars called Messier 67 that is about the same age as the Sun -- indicating that our solar system might have arisen in a similarly dense environment.

The team used several telescopes and instruments, including the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph at European Southern Observatory's La Silla centre in Chile, to collect high-precision measurements of 88 stars in Messier 67. 

"We want to use an open star cluster as laboratory to explore the properties of exoplanets and theories of planet formation", said Roberto Saglia from the Max Planck Institutes in Germany who led the team. 

"Here we have not only many stars possibly hosting planets, but also a dense environment, in which they must have formed," Saglia added.

The study, published in the journal Astronomy and Astrophysics, found that hot Jupiters were more common around stars in Messier 67 than is the case for stars outside of clusters.

A hot Jupiter is a giant exoplanet with a mass of more than about a third of Jupiter's mass. They are "hot" because they orbit close to their parent stars, as indicated by an orbital period (their "year") that is less than 10 days in duration. 

"This is really a striking result," said Anna Brucalassi, who carried out the analysis. 

"The new results mean that there are hot Jupiters around some 5 per cent of the Messier 67 stars studied -- far more than in comparable studies of stars not in clusters, where the rate is more like 1 per cent," Brucalassi added.

​Tokyo, June 20 (IANS) In a first, an international team of astronomers has found firm evidence of the presence of oxygen in the early universe -- only 700 million years after the Big Bang.

Using the Atacama Large Millimetre/submillimetre Array (ALMA) telescope in Chile, the team including scientists from Japan, Sweden, Britain and European Southern Observatory found light from ionised oxygen in the SXDF-NB1006-2 galaxy -- making it the most distant unambiguous detection of oxygen ever obtained.

SXDF-NB1006-2 lies at a redshift of 7.2, meaning that we see it only 700 million years after the Big Bang.

Oxygen in SXDF-NB1006-2 was found to be 10 times less abundant than it is in the Sun, according to the study published recently in the journal Science. 

"The small abundance is expected because the universe was still young and had a short history of star formation at that time," said study co-author Naoki Yoshida from the University of Tokyo. 

"Our simulation actually predicted an abundance 10 times smaller than the Sun. But we have another, unexpected, result: a very small amount of dust," he added.

The detection of ionised oxygen indicates that many very brilliant stars, several dozen times more massive than the Sun, have formed in the galaxy and are emitting the intense ultraviolet light needed to ionise the oxygen atoms.

In the time before objects formed in the universe, it was filled with electrically neutral gas. But when the first objects began to shine, a few hundred million years after the Big Bang, they emitted powerful radiation that started to break up those neutral atoms -- to ionise the gas.

During this phase -- known as cosmic reionisation -- the whole universe changed dramatically. But there is much debate about exactly what kind of objects caused the reionisation. Studying the conditions in very distant galaxies can help to answer this question.

"SXDF-NB1006-2 would be a prototype of the light sources responsible for the cosmic reionisation," said lead author Akio Inoue from Osaka Sangyo University in Japan​

New York, June 20 (IANS) Vocal cords are able to produce a wide range of sound frequencies because of the larynx's ability to stretch vocal cords and the cords' molecular composition, finds a new research.

The larynx's ability to stretch vocal cords and the cords' molecular composition, show how these two characteristics of various species' larynxes can closely predict the range of frequencies each species can produce. 

The findings showed that larger animals had larger larynxes, and body size correlated well with the average frequency an animal could produce.

The mean pitch can be correlated with size with the amount of length change possible in the vocal cord, or how far it could stretch and a factor measuring the stiffness of the cord due to the fibre structures within, the study said.

At birth, vocal cords are composed of a uniform, gel-like material. As the vocal cords mature, fibres develop within the gel, eventually forming a multilayered, laminated string. 

The muscles in the larynx further modulate the sound the cords produce, lengthening and shortening the cords to change the pitch.

For the study, published in PLOS Computational Biology, the team compiled measurements of larynx characteristics for 16 species, including humans and animals ranging from mice to elephants. 

The results may help surgeons repair damaged vocal cords. 

Because both cord stretchiness and stiffness factor into range, doctors may have more options to design treatments to restore much of a patient's range, said Ingo Titze, scientists at the University of Utah in the US. 

The findings also have implications for vocal training, and suggest that singers can increase their ranges by either stretching their vocal cords or by engaging in exercises that affect fiber spacing and cord stiffness.​

​London, June 20 (IANS) The same asteroid that killed the dinosaurs in the Cretaceous period 66 million years ago also wiped out over 90 per cent of mammal species, significantly more than previously thought, new research has found.

Following the asteroid hit, most of the plants and animals would have died, so the survivors probably fed on insects eating dead plants and animals. 

With so little food, only small species survived. The biggest animals to survive on land would have been no larger than a cat, the study said.

For the study, the researchers reviewed all mammal species known from the end of the Cretaceous period in North America. 

Their results showed that over 93 per cent became extinct across the Cretaceous-Paleogene (K-Pg) boundary, but that they also recovered far more quickly than previously thought.

The scientists analysed the published fossil record from western North America from two million years before the Cretaceous-Paleogene boundary, until 300,000 years after the asteroid hit. 

They compared species diversity before and after this extinction event to estimate the severity of the event and how quickly the mammals recovered. 

"The species that are most vulnerable to extinction are the rare ones, and because they are rare, their fossils are less likely to be found. The species that tend to survive are more common, so we tend to find them,” said one of the researchers Nick Longrich from Milner Centre for Evolution in University of Bath in England.

"The fossil record is biased in favour of the species that survived. As bad as things looked before, including more data shows the extinction was more severe than previously believed," Longrich noted.

The researchers said this explains why the severity of the extinction event was previously underestimated. 

The study was published in the Journal of Evolutionary Biology.

​New York, June 18 (IANS) Scientists have identified a single gene pathway that can disrupt Zika and similar viruses from spreading in the body and also act as a potential drug target for such deadly diseases.

The findings showed that disabling SPCS1 -- in both human and insect cells -- reduces viral infection and does not negatively affect the cells themselves.

"We wanted to find out if we could identify genes present in the host cells that are absolutely required by the virus for infection," said Michael Diamond, Professor at Washington University.

While the absence of SPCS1 gene shut down the spread of flaviviruses, eliminating the gene had no detrimental effect on other types of viruses, including alphaviruses, bunyaviruses and rhabdoviruses, the researchers said.

"In these viruses, without SPCS1 gene the chain reaction doesn't happen and the virus can't spread. So this gene can act as a potential drug target because it disrupts the virus but not the host," Diamond added.

Viruses hijack host cells to replicate and spread, making them dependent upon the genetic material of the organisms they infect. 

If a cell lacks a gene that the virus requires for infection, the virus will have to stop in its tracks and will enable the cells to survive. Thus the missing gene becomes vital to spread of the virus.

"Flaviviruses appear to be uniquely dependent particularly on SPCS1 gene to release the viral particle," Diamond noted. 

For the study, published in the journal Nature, the team first conducted experiments on West Nile virus and then found that the same results held true for other Flaviviridae family members, including Zika, dengue, yellow fever, Japanese encephalitis and hepatitis C viruses.

Using gene-editing technology called CRISPR that is capable of selectively shutting down individual genes, the researchers identified only nine key genes that the virus relies on for infection or to spread. ​

​New York, June 19 (IANS) Consuming high-quality plant-based diet such as whole grains, fruits, vegetables, nuts, seeds and legumes, can substantially lower the risk of developing Type 2 diabetes, says a new study led by an Indian-origin scientist.

The findings showed that eating a healthy version of such diet was linked with a 34 per cent lower diabetes risk, while a less healthy version -- including foods such as refined grains, potatoes, and sugar-sweetened beverages -- was linked with a 16 per cent increased risk.

Such diets are high in fibre, antioxidants, unsaturated fatty acids, and micronutrients such as magnesium and are low in saturated fat.

"The study highlights that even moderate dietary changes in the direction of a healthful plant-based diet can play a significant role in the prevention of type 2 diabetes," said Ambika Satija, professor at the Harvard T.H. Chan School of Public Health in Boston.

Adherence to a plant-based diet was found low in animal foods, with a 20 per cent reduced risk of Type 2 diabetes.

Healthy plant foods may also be contributing to a healthy gut microbiome, the authors said.

"A shift to dietary pattern marking higher plant-based foods and lower in animal-based foods, especially red and processed meats, can confer substantial health benefits in reducing risk of type 2 diabetes," added Frank Hu, Professor at Harvard Chan School.

The study, published in an online journal named PLOS Medicine, was the first to make distinctions between healthy plant-based diets and less healthy ones that include things like sweetened foods and beverages, and some animal foods, which may be detrimental for health.

The researchers conducted a 20 years survey of more than 200,000 male and female health professionals, and questioned them on their diet, lifestyle, medical history, and new disease diagnoses.

The diets of the participants were evaluated using a plant-based diet index, in which they assigned plant-derived foods in higher scores than animal-derived foods.

"These findings provide further evidence to support current dietary recommendations for chronic disease prevention," Satija suggested.​