Knowledge Update

​Beijing, Nov 11 (IANS) Scientists have discovered a dinosaur fossil -- nicknamed the 'Mud Dragon' -- that can help them better understand how the last-surviving dinosaurs were flourishing before their mass extinction.

'Mud Dragon', which meant 'muddy dragon on the road to heaven', was a bird-like species, discovered from a building site near Ganzhou in China. 

According to the study published in journal Scientific Reports, the two-legged animal belonged to a family of feathered dinosaurs called oviraptorosaurs. They were characterised by having short, toothless heads and sharp beaks.

"This new dinosaur is one of the most beautiful, but saddest, fossils. Its skeleton is one of the best examples of a dinosaur that was flourishing during those final few million years before the asteroid came down and changed the world in an instant," said Steve Brusatte of the University of Edinburgh in Scotland.

Fossil discoveries in recent decades suggest that this group of flightless animals were experiencing a numbers boost, diversifying into new species, during the 15 million years before the dinosaurs went extinct, the researchers noted. 

Further, the study showed that it was probably one of the last groups of dinosaurs to diversify before the asteroid impact 66 million years ago, which killed off all of the non-bird dinosaurs.

The fossil remains was remarkably well preserved and almost intact, lying on its front with its wings and neck outstretched.

According to scientists, the creature may have died in this pose after becoming mired in mud about 66-72 million years ago.

​New York, Nov 11 (IANS) Researchers from the University of Missouri School of Medicine has come out with a new test to check eye pressure to prevent possible vision loss.

The most common complication from cataract surgery is high eye pressure, which can cause swelling and other issues that can lead to vision loss or even blindness. 

"The current standard of care following cataract surgery is to refill the eye with a saline solution and tap on the eye with a Q-tip to observe if it is too firm, too soft or just right," said John Jarstad, Associate Professor at the University of Missouri School of Medicine in a statement.

"This Goldilocks-style guesstimate often is inaccurate, and patients might actually have higher eye fluid pressure than the surgeon believes. We use a device known as a tonometer to accurately gauge eye pressure," Jarstad added.

An electronic eye pressure monitoring device known as a tonometer often is used in a clinical setting to determine eye pressure, but the device rarely is used in a surgical setting. 

The researchers studied 170 patients who had eye pressure adjusted after cataract surgery with a tonometer and found that patients were 2.5 to 4 times less likely to develop cystoid macular edema -- cyst-like pockets of fluid in the macula of the eye.

According to the researchers, normal eye pressure should be between 16 and 21 mmHg, or millimeters of mercury.

In most cases, a high eye pressure will resolve itself in a matter of days without issue, but in cases in which the pressure is significantly high, a person can experience symptoms of nausea and pain above the eyebrow.

In these cases, it's important that the pressure be adjusted to prevent permanent damage to the eye, the study suggested.

"I recommend eye surgeons adopt this practice for the good of their patients. There is no additional cost to patients, and if it saves just one patient from going blind, it would be well worth every doctor using it in his or her surgical practice," the researcher said

New York, Nov 11 (IANS) In a major breakthrough, a team of researchers, including one of Indian origin, has identified two chemicals that can help develop heart cells that can beat harder, faster and stronger, bringing technology one step closer to regenerating damaged hearts.

Scientists from Gladstone Institute of Cardiovascular Disease, in San Francisco, US, tested 5,500 chemicals, and identified two that can potentially transform a scar tissue into healthy beating heart muscle -- a discovery that can help find new and effective treatments for heart failure. 

The two chemicals increased eightfold the number of heart cells created, as well as sped up the process of cell conversion, achieving in one week what used to take six to eight weeks, the study said.

"The study discovered that chemically inhibiting two biological pathways active in embryonic formation improves the speed, quantity, and quality of the heart cells produced from our original process," said senior author Deepak Srivastava, Director of the Gladstone Institute of Cardiovascular Disease. 

After suffering a heart attack, the connective tissues develop scar tissue, which then contribute to heart failure.

When the heart muscle gets damaged, the body is unable to repair the dead or injured cells.

According to researchers, the first chemical inhibits a growth factor that helps cells grow and divide and is important for repairing tissue after injury. 

The second chemical inhibits an important pathway that regulates heart development. 

By combining the two chemicals with the current method -- of reprogramming connective tissue cells into heart muscle cells using certain proteins -- the researchers successfully regenerated heart muscle and greatly improved heart function in mice that had suffered a heart attack.

In addition, the chemicals were also used to improve direct cardiac reprogramming of human cells, which is a more complicated process that requires additional factors, the researchers noted in the paper published in the journal Circulation.

London, Nov 10 (IANS) Scientists have for the first time used a neural prosthetic to restore walking movement directly to the legs of non-human primates.

In the study, the researchers from Brown University in Rhode Island, US, used a wireless "brain-spinal interface" to bypass spinal cord injuries in a pair of rhesus macaques, restoring intentional walking movement to a temporarily paralysed leg. 

Walking is made possible by a complex interplay among neurons in the brain and spinal cord. 

Electrical signals originating in the brain's motor cortex travel down to the lumbar region in the lower spinal cord, where they activate motor neurons that coordinate the movement of muscles responsible for extending and flexing the leg.

To calibrate the decoding of brain signals, the researchers implanted the brain sensor and wireless transmitter in healthy macaques. The signals relayed by the sensor could then be mapped onto the animals' leg movements. 

They showed that the decoder was able to accurately predict the brain states associated with extension and flexion of leg muscles.

"The system we have developed uses signals recorded from the motor cortex of the brain to trigger coordinated electrical stimulation of nerves in the spine that are responsible for locomotion," said David Borton, Assistant Professor at Brown University.

The study, published in the Journal Nature, suggests that a brain-controlled spinal stimulation system may enhance rehabilitation after a spinal cord injury.

New York, Nov 10 (IANS) Researchers have identified a gene -- previously known only to regulate bone growth and muscle metabolism in mammals -- that can also act as a promoter of brain maturation, cognition and learning in human and non-human primates.

The findings showed that osteocrin -- a gene found in the skeletal muscles of all mammals -- is completely turned off in rodent brains yet highly active in the brains of non-human primates and humans.

However, the activity of the gene was most intense in neurons of the neocortex, the topmost layer of cells covering the brain and responsible for higher-level cognition, such as long-term memory, thought and language. 

At the same time, osteocrin was noticeably absent from other parts of the brain responsible for non-cognitive functions such as spatial navigation, balance, breathing, heart rate and temperature control.

This suggests a possible role of the gene in the development of cognition -- a cardinal feature that distinguishes the brains of human and non-human primates from those of other mammals, the researchers said.

"We have uncovered what we believe is a critical clue into the evolution of the human brain, one that gives us a glimpse into the genetic mechanisms that may account for differences in cognition between mice and humans," said Michael Greenberg, Professor at the Harvard Medical School, in Boston, US.

Further analysis revealed that osteocrin's activation curbed the growth of neuronal dendrites -- branchlike projections responsible for transmitting signals from one brain cell to the next.

"Restricting dendritic growth is a precision-enhancing mechanism, essential to ensuring that neuronal wires don't get crossed and compromise signal transmission from one cell to the next," added Bulent Ataman, neurobiologist at the Harvard Medical School.

This observation suggests that osteocrin's activity may help enhance nerve cell agility and proper signal transmission to ensure robust communication across neurons, Ataman said.

For their experiments, published in the journal Nature, the team analysed RNA levels -- the molecular footprints of gene activity -- in the brain cells of mice, rats and humans. 

​New York, Nov 10 (IANS) The Indian Ocean's Agulhas Current -- one of the strongest currents in the world -- is getting wider rather than strengthening, which will have important implications for global climate change, a study says.

The findings suggest that intensifying winds in the region may be increasing the turbulence of the current, rather than increasing its flow rate.

"To find decades of broadening, rather than intensification, profoundly impacts our understanding of the Agulhas Current and its future role in climate change," said study co-author Shane Elipot of the University of Miami's Rosenstiel School of Marine and Atmospheric Science in the US.

The Agulhas Current flows along the east coast of South Africa, transporting warm, salty water away from the tropics toward the poles.

Using measurements collected during three scientific cruises to the Agulhas Current, the Indian Ocean's version of the Gulf Stream, the researchers estimated the long-term transport of the current leveraging 22 years of satellite data. 

They found the Agulhas Current has broadened, not strengthened, since the early 1990s, due to more turbulence from increased eddying and meandering.

"Increased eddying and meandering could act to decrease poleward heat transport, while increasing coastal upwelling and the exchange of pollutants and larvae across the current from the coast to the open ocean," Elipot said.

The Agulhas, which is hundreds of kilometres long and over 2,000-metres deep, transports large amounts of ocean heat and is considered to have an influence not only on the regional climate of Africa, but on global climate as part of the ocean's global overturning circulation.

"Changes in western boundary currents could exacerbate or mitigate future climate change," lead author of the study Lisa Beal, also a professor at the Rosenstiel School noted.

"Currently, western boundary current regions are warming at three times the rate of the rest of the world ocean and our research suggests this may be related to a broadening of these current systems," Beal said

London, Nov 9 (IANS) Extending the number of pregnant women given a common drug to boost thyroid hormone levels may lead to a reduced number of still-births, early caesarean sections and low-weight babies, says a new study.

"Our work raises the possibility of providing real benefits from using a safe, cheap and well established treatment by simply extending it to the number of pregnant women we treat," said lead author of the study Peter Taylor from University of Cardiff in Britain.

The thyroid gland is an organ found in the base of the neck. It produces essential hormones that control the body's metabolism -- the way we use energy. 

Thyroid hormones are also critical for foetal brain development, but babies cannot make any of their own until the second trimester and have to source all of it from their mothers.

Pregnant women with mild hypothyroidism have low levels of thyroid hormones. This can be treated with a hormone replacement drug called levothyroxine.

In this study, the researchers investigated whether pregnant women with mild hypothyroidism and their babies would also benefit from levothyroxine treatment. 

They combined data from a thyroid screening study and linked it to routinely collected clinical data to study the effect of correcting borderline thyroid function on obstetric outcomes.

The researchers analysed over 13,000 women who were 12-16 weeks pregnant, 518 of whom had mild hypothyroidism. 

Of these, 263 women received levothyroxine and the rest received no treatment. 

They assessed the women's pregnancy outcomes by measuring stillbirth rates, preterm delivery, length of stay at hospital, birth weight and the number of early caesarean sections.

They found that women with mild hypothyroidism treated with levothyroxine had a lower risk of giving birth to low weight babies and were also less likely to undergo an early caesarean.

Untreated women with mild hypothyroidism were more likely to have a stillbirth than women with normal thyroid function and no stillbirths occurred in the treated group. 

The findings were presented at the Society for Endocrinology's annual conference in Brighton, England.

​New York, Nov 9 (IANS) Neanderthal genetic material is found in only small amounts in the genomes of modern humans because, after inter-breeding, natural selection removed large numbers of weakly deleterious Neanderthal gene variants, says a study.

Humans and Neanderthals inter-bred tens of thousands of years ago, but today, Neanderthal DNA makes up only one to four per cent of the genomes of modern non-African people. 

"For a while now we have known that humans and Neanderthals hybridised. Many Europeans and Asians - along with other non-African populations - are the descendants of those hybrids," said Ivan Juric from the University of California, Davis in the US.

"Previous work has also shown that, following hybridisation, many Neanderthal gene variants were lost from the modern human population due to selection. We wanted to better understand the causes of this loss," Juric noted.

To understand how modern humans lost their Neanderthal genetic material and how humans and Neanderthals remained distinct, the researchers developed a novel method for estimating the average strength of natural selection against Neanderthal genetic material.

They found that natural selection removed many Neanderthal alleles from the genome that might have had mildly negative effects. 

The scientists estimated that these gene variations were able to persist in Neanderthals because Neanderthals had a much smaller population size than humans. 

Once transferred into the human genome, however, these alleles became subject to natural selection, which was more effective in the larger human populations and has removed these gene variants over time.

"Our results are compatible with a scenario where the Neanderthal genome accumulated many weakly deleterious variants, because selection was not effective in the small Neanderthal populations. Those variants entered the human population after hybridisation," Juric said.

"Once in the larger human population, those deleterious variants were slowly purged by natural selection," Juric noted.

These findings, published in the journal PLOS Genetics, shed new light on the role of population size on losing or maintaining Neanderthal ancestry in humans.

New York, Nov 9 (IANS) Offering a potential new tool to study respiratory diseases, researchers have transplanted lab-grown mini lungs into immunosuppressed mice where the structures were able to survive, grow and mature.

"In many ways, the transplanted mini lungs were indistinguishable from human adult tissue," said senior study author Jason Spence, Associate Professor at University of Michigan Medical School in the US.

Respiratory diseases account for nearly one in five deaths worldwide, and lung cancer survival rates remain poor despite numerous therapeutic advances during the past 30 years.

The numbers highlight the need for new, physiologically relevant models for translational lung research.

Lab-grown lungs can help because they provide a human model to screen drugs, understand gene function, generate transplantable tissue and study complex human diseases, such as asthma.

The researchers used numerous signalling pathways involved with cell growth and organ formation to coax stem cells -- the body's master cells -- to make the miniature lungs.

The findings, published in the journal eLife, suggest that scientists can now grow 3-D models of lungs from stem cells, creating new ways to study respiratory diseases.

New York, Nov 9 (IANS) Chimpanzees -- highly promiscuous species -- are good fathers and more devoted to protect their offspring than previously thought, a research has revealed.

The study led by researchers from the George Washington University showed that male chimpanzees spend time with non-mating female chimpanzees that are caring for their offspring.

They interact with their infants more than expected as well as spend time on grooming and caring them.

"This research suggests that male chimpanzees may sometimes prioritise relationships with their offspring rather than with potential mates," said Carson Murray, Assistant Professor at the George Washington University.

However, the chimpanzees spending time with nursing mothers did not increase the likelihood that they would be the father of that mother's next infant, the researchers said.

They said this finding is unexpected since the species is highly promiscuous and researchers previously questioned whether male chimpanzees could recognise their offspring.

For the study, the team examined patterns based on 17 father chimpanzees and 49 mother-infant pairs to see if the males could recognise their offspring and if the male's behaviour was different around them.

The results showed that the males associated with mothers of their offspring early in infancy and interacted with their infants more than expected.

The research was published in Royal Society Open Science.