Knowledge Update

London, March 15 (IANS) Stimulating the brain with electricity may synchronise brain waves and help improve short-term working memory that could improve treatments for people with traumatic brain injury, stroke or epilepsy, a study has found.

According to researchers, applying a weak electrical current through the scalp can align different parts of the brain, synchronising brain waves and enabling people to perform better on tasks involving working memory.

"What we observed is that people performed better when the two waves had the same rhythm and at the same time," said lead author Ines Ribeiro Violante, a neuroscientist at the Imperial College London.

"The hope is that it could eventually be used for patients with brain injury, or even those who have suffered a stroke or who have epilepsy," Violante added. 

For the study, published in the journal eLife, the team used a technique called transcranial alternating current stimulation (TACS) to manipulate the brain's regular rhythm in 10 volunteers.

Using TCAS, the researchers targeted two brain regions -- the middle frontal gyrus and the inferior parietal lobule -- known to be involved in working memory.

The findings revealed that when the brain regions were stimulated in sync, reaction times on the memory tasks improved.

Functional MRI images of the brain showed changes in activity occurring during stimulation, with the electrical current potentially modulating the flow of information.

"The results show that when the stimulation was in sync, there was an increase in activity in those regions involved in the task. When it was out of sync, the opposite effect was seen.

"The hope is that it could eventually be used for patients with brain injury, or even those who have suffered a stroke or who have epilepsy," Violante added.

​Buenos Aires, March 14 (IANS) The worlds first fluorescent frog has been discovered in the Amazon basin in Argentina, a media report said on Tuesday.

Scientists at the Bernardino Rivadavia Natural Sciences Museum in Buenos Aires made the discovery by accident while studying the pigment of polka-dot tree frogs, a species common to the rainforest, the Guardian said in the report.

In normal light the frog appears to have a dull, mottled brown-green skin with red dots, but under UV light it glows a bright fluorescent green.

Fluorescence -- the ability to absorb light at short wavelengths and re-emit it at longer wavelengths -- is uncommon in creatures that live on land.

The translucent frog was found to use a combination of lymph and glandular emissions to fluoresce.

The researchers, who published their discovery on Monday in Proceedings of the National Academy of Sciences, found that the trait enhanced the brightness of the frog by 19-29 per cent depending on the level of ambient light in its surroundings, the daily said.

The compound causing the blue-green glow of the polka-dot tree frog was not previously thought to exist in vertebrates and its discovery has excited researchers.

"This is very different from fluorophores found in other vertebrates, which are usually proteins or polyenic chains," Maria Gabriella Lagoria, a photochemist at the University of Buenos Aires and study co-author, told Chemistry World.

The discovery opens up the possibility that other amphibians may be able to fluoresce, particularly those with translucent skin similar to that of the tree frog.

Speaking to the journal Nature, which first published news of the fluorescent frog, co-author Julian Faivovich expressed his hope that the discovery would inspire interest in the phenomenon, saying he hoped scientists would "start carrying a UV flashlight to the field".

​London, March 14 (IANS) Although parenthood may have its share of woes, it could also hold the key to long life, particularly in older age, when health and capacity may start to decline, finds a new study.

The findings suggested that the risks of death were lower among those who had had at least one child than they were among those who were childless -- and more so among men than among women -- and were not affected by the sex of the child(ren).

"We started first at the age of 60 and we looked all the way up to the age of 100," Karin Modig from Karolinska Institute Sweden was quoted as saying by guardian.com.

At age 60, the difference in the one-year risk of death was 0.06 per cent among men and 0.16 per cent among women.

The one-year risk of death for an 80-year-old man with a child was 7.4 per cent, for example, compared with 8.3 per cent for a childless man of the same age.

The gap in absolute death risks between the two groups rose with increasing age, and was somewhat larger for men than it was for women.

By the age of 90, these differences had risen to 1.47 per cent among men and to 1.10 per cent among women.

Further, the difference in death risk was 1.2 per cent among unmarried men and 0.6 per cent among those who were married.

"Our finding that the association grew stronger when parents became older is further in agreement with study suggesting that childless people face support deficits only towards the end of life," the researchers noted, in the paper published online in the Journal of Epidemiology & Community Health.

For the study, the team tracked the lifespan from the age of 60 onwards of all men (704,481) and women (725,290) in Sweden.

Tokyo, March 14 (IANS) Japanese authorities sent a robot to the Fukushima nuclear plant on Tuesday to measure radiation levels inside and evaluate its condition ahead of a future dismantling of a reactor.

The self-propelled, remotely-operated robot is equipped with a video camera, thermometer as well as dosimeter -- to measure radiation -- among other sensors, said the Tokyo Electric Power Company (TEPCO), the maker of the bot, in a statement.

Using the recorded data and footage, experts will try to ascertain the presence of melted fuel that could have leaked from the reactor core and accumulated at the bottom of the containment vessel, something they have been unable to verify so far, Efe news reported.

Determining the exact conditions inside the reactor is a necessary step for drafting a plan on the future recovery of the nuclear fuel; a task that has been made difficult by fatal radiation levels at the heart of the nuclear installations.

TEPCO had introduced two bots into the reactor earlier but while the first one could not make it out of the reactor, the second one became inoperative due to extreme radiation.

Another robot that TEPCO sent was also damaged by radiation, but managed to record footage that supplied important information on conditions inside, said the company.

Reactors No. 1, 2 and 3 had suffered partial meltdowns due to an earthquake and a tsunami that hit Japan in March 2011.

The Fukushima nuclear accident is considered the world's worst since Ukraine's Chernobyl disaster in 1986. 

​New York, March 14 (IANS) Scientists have, in a monkey model of HIV, discovered that a dual-antibody therapy can boost the immune system to effectively control the infection and prevent deadly virus from returning for an extended period.

There are more than 25 drugs to control HIV, yet the virus remains one of the world's biggest health problems. 

In the study, the researchers used two drugs -- 3BNC117 and 10-1074 -- belonging to a class of molecules called broadly neutralising antibodies, where each antibody binds to a different site of the virus, preventing its damaging effects from different angles.

"This form of therapy can induce potent immunity to HIV, allowing the host to control the infection," said Michel Nussenzweig from the Howard Hughes Medical Institute -- a US-based non-profit. 

"It works by taking advantage of the immune system's natural defenses, similar to what happens in some forms of cancer immunotherapy," Nussenzweig added.

For the study, published in the journal Nature, the team analysed 13 macaque monkeys, who were inoculated with simian-human immunodeficiency virus (SHIV) and then given three intravenous infusions of the two antibodies over a two-week period. 

The treatment suppressed the virus to levels near or below the limit of detection and its effect lasted for as long as six months. 

These monkeys were also able to maintain healthy levels of key immune cells after receiving the antibody infusions.

In those, who did not regain complete control of the virus, the treatment helped them maintain extremely low viral loads and healthy levels of key immune cells for two to three years after infection.

Although this model does not precisely mimic human HIV infection, the findings suggest that immunotherapy should be explored as a way of controlling the virus and boosting an immune response that might be capable of controlling the infection in people.

London, March 14 (IANS) In a first, scientists have created the three-dimensional (3-D) structures of intact mammalian genomes from individual cells, leading to a potential advance of stem cells in medicine.

The 3-D structure shows how the DNA from all the chromosomes intricately folds to fit together inside the cell nuclei.

The new approach, detailed in the journal Nature, also enables researchers to determine the structures of active chromosomes inside the cell and how they interact with each other to form an intact genome.

"Visualising a genome in 3D at such an unprecedented level of detail is an exciting step forward in research and one that has been many years in the making. This detail will reveal some of the underlying principles that govern the organisation of our genomes - for example how chromosomes interact or how structure can influence whether genes are switched on or off," said Tom Collins from Wellcome trust -- a London-based non-profit. 

The genome's structure controls when and how strongly genes -- particular regions of the DNA -- are switched 'on' or 'off,' while playing a critical role in the development of organisms and also, when it goes awry, in disease.

The study may help study how this changes as stem cells differentiate and how decisions are made in individual developing stem cells, which may be key to realising the potential of stem cells in medicine.

"If we can apply this method to cells with abnormal genomes, such as cancer cells, we may be able to better understand what exactly goes wrong to cause disease, and how we could develop solutions to correct this," Collins said.

​New York, March 14 (IANS) US researchers have developed a new hormone-based test that can better distinguish between the symptoms of depression and schizophrenia.

Depression is thought to affect over 300 million people worldwide and schizophrenia affects as many as 51 million people. 

Clinically, it is difficult to distinguish between these two diseases in their early phases, because symptoms are non-specific and relatively mild. 

In the study, led by researchers from Yale University in Connecticut, US, the researchers infused patients with a high concentration salt solution to induce the release of the hormone arginine-vasopressin (AVP), and then measured the level of the hormone in their blood. 

The results, reported in Experimental Physiology, revealed that AVP release can distinguish schizophrenia from depression.

Depressed patients showed an increased release of the hormone, while patients with schizophrenia showed a decreased response. 

Further, the novel method will help identify people whose depression or schizophrenia involves signalling via a receptor called NMDAR, and differentiate between the two diseases. 

In patients with schizophrenia the NMDA receptor signalling may be decreased, while it might be high in those with depression. 

This hormone test may be a simple way to distinguish and identify patients with NMDA receptor malfunction in each disorder, the researchers said. 

"This is the first objective, physiological marker for two major psychiatric disorders that, once fully developed into a clinical test, can allow for earlier and more accurate diagnosis, and selection of more appropriate medications for patients," said Handan Gunduz-Bruce from Yale University.

Distinguishing this specific form of these diseases could allow for earlier and more accurate diagnoses as well as more targeted treatment, Gunduz-Bruce added.

New York, March 14 (IANS) Researchers have found evidence of a white dwarf star orbiting a likely black hole at a distance of only 961,000 km -- just about 2.5 times the distance between the Earth and the Moon.

In a tightest orbital dance ever witnessed for a black hole and a companion star, the star whips around the black hole at an astonishing speed -- about two orbits an hour, said the study published in the journal Monthly Notices of the Royal Astronomical Society.

"This white dwarf is so close to the black hole that material is being pulled away from the star and dumped onto a disk of matter around the black hole before falling in," said study lead author Arash Bahramian, affiliated with the University of Alberta in Canada and Michigan State University in the US. 

"Luckily for this star, we don't think it will follow this path into oblivion, but instead will stay in orbit," Bahramian said.

Although the white dwarf does not appear to be in danger of falling in or being torn apart by the black hole, its fate is uncertain.

The stellar system, known as X9, is located in the globular cluster 47 Tucanae, a dense cluster of stars in our galaxy about 14,800 light years away from the Earth. 

"For a long time astronomers thought that black holes were rare or totally absent in globular star clusters," study co-author Jay Strader from Michigan State University said. 

"This discovery is additional evidence that, rather than being one of the worst places to look for black holes, globular clusters might be one of the best," Strader added.

For the study, the researchers used data from the Australia Telescope Compact Array as well as NASA's Chandra X-ray Observatory and NuSTAR telescope.

Washington, March 14 (IANS) Rapid loss of Arctic sea ice in recent decades is partly driven by natural swings, not just global warming triggered by human activities, says a study.

A shift in wind patterns is responsible for about 60 per cent of sea ice loss in the Arctic Ocean since 1979, the researchers found. 

Some of this shift is related to climate change, but the study showed that 30-50 per cent of the observed sea ice loss since 1979 is due to natural variations in this large-scale atmospheric pattern.

"Anthropogenic forcing is still dominant -- it's still the key player," said the study's lead author Qinghua Ding, climate scientist at the University of California at Santa Barbara in the US.

"But we found that natural variability has helped to accelerate this melting, especially over the past 20 years," Ding said.

The paper builds on previous work that found changes in the tropical Pacific Ocean have in recent decades created a "hot spot" over Greenland and the Canadian Arctic that has boosted warming in that region.

The hot spot is a large region of higher pressure where air is squeezed together so it becomes warmer and can hold more moisture, both of which bring more heat to the sea ice below. 

The new paper, published in the journal Nature Climate Change, focuses specifically on what this atmospheric circulation means for Arctic sea ice in September, when the ocean reaches its maximum area of open water.

"This study provides the mechanism and uses a new approach to illuminate the processes that are responsible for these changes," the study's second author Axel Schweiger, a University of Washington polar scientist who tracks Arctic sea ice, said. 

"The method is really innovative, and it nails down how much of the observed sea ice trend we've seen in recent decades in the Arctic is due to natural variability and how much is due to greenhouse gases," co-author David Battisti, Professor at University of Washington, noted.

The researchers believe that teasing apart the natural and human-caused parts of sea ice decline would help to predict future sea ice conditions in Arctic summer.

New York, March 12 (IANS) Children between age 3 and 7 who do not get enough sleep are more likely to have problems with attention, emotional control and peer relationships, says a study.

"We found that children who get an insufficient amount of sleep in their pre-school and early school-age years have a higher risk of poor neuro-behavioral function at around age 7," said lead researcher Elsie Taveras from the MassGeneral Hospital for Children in the US.

"The associations between insufficient sleep and poorer functioning persisted even after adjusting for several factors that could influence the relationship," Taveras said.

As in previous studies from this group examining the role of sleep in several areas of child health, the current study analysed data from Project Viva, a long-term investigation of the health impacts of several factors during pregnancy and after birth.

Information used in this study was gathered from mothers at in-person interviews when their children were around 6 months, 3 years and 7 years old, and from questionnaires completed when the children were aged 1, 2, 4, 5 and 6 years.

In addition, mothers and teachers were sent survey instruments evaluating each child's executive function - which includes attention, working memory, reasoning and problem solving -- and behavioural issues -- including emotional symptoms and problems with conduct or peer relationships, when children were around 7.

Among 1,046 children enrolled in Project Viva, the study team determined which children were not receiving the recommended amount of sleep at specific age categories -- 12 hours or longer at ages 6 months to 2 years, 11 hours or longer at ages 3 to 4 years, and 10 hours or longer at 5 to 7 years.

The study, published online in the journal Academic Pediatrics, found significant differences in the responses of parents and teachers to surveys regarding executive function and behavioural problems in 7-year-old children depending on how much sleep they regularly got at younger ages.