Knowledge Update

New York, Sep 16 (IANS) In a first study of its magnitude, researchers in the US aim to infuse an antibody into human immunodeficiency virus (HIV)-negative men and transgender individuals to determine whether it will prevent the infection from developing.

The Antibody Meditated Prevention (AMP) study -- led by an Indian-origin scientist -- aims to recruit a combined 2,700 HIV-negative men and transgender individuals whose sexual partners are men -- the highest-risk demographic for HIV infection -- to test the efficacy of antibody VRC01 in the large clinical trial. 

"It is the first study of this magnitude to see whether an antibody infusion can help prevent new HIV infections. If it proves effective, it could potentially pave a way for developing a vaccine for HIV infection," said Shobha Swaminathan, an infectious disease specialist from Rutgers University in New Jersey, US.

The VRC01 antibody was initially detected in an individual who was able to successfully control HIV infection without taking any medications for HIV.

Further, in laboratory tests, VRC01 antibody has shown to be effective against 90 per cent of HIV-1 isolates that were tested, the researchers said. 

Those enrolled will either be given intravenous infusions of VRC01 or a placebo every eight weeks for a total of 10 infusions.

Participants will be closely monitored for approximately 22 months for safety and also to determine whether they have remained HIV-negative.

HIV continues to be a major global public health issue, though the rate of infection has fallen significantly in recent years. 

In 2014, gay and bisexual men accounted for an estimated 83 per cent of all new HIV infections among men in the US, according to the Centers for Disease Control (CDC).

Though the number of new HIV diagnoses fell 19 per cent from 2005 to 2014, certain demographic groups showed increases in the infection, CDC noted. 

"According to CDC estimates, only about 25 per cent of people who are HIV-positive have it under control," says Swaminathan.

​New York, Sep 16 (IANS) Researchers at Harvard Medical School have found how certain tumours develop a taste for fat over sugar and that one way to kill them could be starving them of their life-sustaining fuel.

The findings showed how a mechanism that normally keeps fat burning in check goes awry in some cancers, revving up fat consumption and fuelling tumour growth.

"This really represents a new frontier in looking at the metabolism of cancer," said senior author of the study Marcia Haigis, Associate Professor of Cell Biology.

"Understanding the molecular handle of this pathway is the first step toward translating the basic work into therapy," Haigis said.

Specifically, the study, published in the journal Molecular Cell, found that a protein called prolyl hydroxylase 3 (PHD3) appears to be a key regulator of the delicate balance inside cells that dampens fat burning. 

That protein, the research showed, is abnormally low in certain forms of cancer - a finding that can help lay the ground for development of therapies that work by starving tumours of their fuel.

Two forms of cancer -- acute myeloid leukemia and prostate cancer -- had by far the lowest PHD3 levels, the analysis showed.

To test their hypothesis that these particular cancers needed fats to survive and that PHD3 was a key regulator in the fat-burning process fuelling tumour growth, the researchers restored to normal the levels of PHD3 in a line of cancer cells and in mice. 

The tumours not only stopped growing, they died.

"That was really exciting," Haigis said. 

"We've altered a lot of metabolic pathways in cancer, and this is one of the few pathways we've modulated where we really see the tumours die. They are so dependent on fat oxidation that they die," Haigis noted.

Before this discovery can move ahead to the clinic, she said, more basic research needs to be done, both in animal models and in cancer cells taken from patients, to understand why certain tumours depend on fat.

New York, Sep 16 (IANS) A team of researchers in the US has developed a new inverter that -- despite being smaller and lighter -- improves the fuel-efficiency and range of hybrid and electric vehicles.

Electric and hybrid vehicles rely on inverter components, which are made of the semiconductor material silicon, to ensure that enough electricity is conveyed from the battery to the motor during vehicle operation.

Now researchers at the Future Renewable Electric Energy Distribution and Management (FREEDM) Systems Centre at North Carolina State University have developed an inverter using components made of the wide-bandgap semiconductor material silicon carbide (SiC).

"Our silicon carbide prototype inverter can transfer 99 per cent of energy to the motor, which is about two per cent higher than the best silicon-based inverters under normal conditions," said Iqbal Husain, ABB Distinguished Professor of Electrical and Computer Engineering.

The new SiC-based inverter is able to convey 12.1 kilowatts of power per liter (kW/L) -- close to the US Department of Energy's goal of developing inverters that can achieve 13.4 kW/L by 2020. By way of comparison, a 2010 electric vehicle could achieve only 4.1 kW/L.

"Conventional, silicon-based inverters have likely improved since 2010 but they are still nowhere near 12.1 kW/L," Husain noted in a statement provided by the university.

According to the researchers, they can make an air-cooled inverter up to 35 kW using the new module, for use in motorcycles, hybrid vehicles and scooters.

"The silicon carbide inverters can be smaller and lighter than their silicon counterparts, further improving the range of electric vehicles. And new advances we have made in inverter components should allow us to make the inverters even smaller still," added Husain, who is also the director of the FREEDM Centre. 

The current SiC inverter prototype was designed to go up to 55 kW -- the sort of power you would see in a hybrid vehicle. 

The researchers are now in the process of scaling it up to 100 kW -- akin to what would see in a fully electric vehicle -- using off-the-shelf components, the research paper, to be presented at the IEEE Energy Conversion Congress and Exposition (ECCE), being held from September 18-22 in Milwaukee, US said.

New York, Sep 16 (IANS) It is an immediate, intrinsic response of the hepatitis A virus (HAV)-infected cell that results in liver inflammation, researchers at University of North Carolina at Chapel Hill have discovered.

HAV does not cause chronic liver disease like hepatitis B and C viruses. But in rare cases, it can cause acute liver failure, which is often fatal.

The new findings, published in the journal Science, could lead to new response to control the infection as hepatitis researchers earlier thought that immune cells sent by the body to attack virus-infected cells in the liver cause the acute liver injury.

"The virus evokes a response in the infected cell that activates a pre-programmed cell death pathway," said one of the study authors Stanley Lemon, Professor of Medicine.

"In effect, the cell commits suicide, sacrificing itself along with the virus in an effort to save the host. This results in inflammation within the liver that we recognise as hepatitis," Lemon explained.

Hepatitis A virus is a vaccine preventable form of infectious hepatitis. HAV is found worldwide and is transmitted through ingestion of food and water that is contaminated with the feces of an infected person. 

Symptoms of hepatitis A include nausea, stomach pain, fever, sore throat, headache and diarrhea. 

People infected with HAV may not experience any symptoms, but shed the virus for two to four weeks. During this period, an infected person can pass the virus to others.

​London, Sep 17 (IANS) The memory of a heart attack gets stored in genes through epigenetic changes -- chemical modifications of DNA that turns our genes on or off, a study has found.

Cardiovascular diseases (CVDs) which are the leading causes of death worldwide are influenced by both heredity and environmental factors. 

CVD includes all the diseases of the heart and circulation including coronary heart disease, angina, heart attack, congenital heart disease and stroke. 

The study examined epigenetic changes -- that can lead to the development of various diseases -- in people who have had a previous heart attack.

"During a heart attack the body signals by activating certain genes. This mechanism protects the tissue during the acute phase of the disease, and restores the body after the heart attack. It is therefore likely that epigenetic changes are also associated a heart attack", said Asa Johansson, researcher at the Uppsala University in Sweden.

The results of the study showed that there are many epigenetic changes in individuals who had experienced a heart attack. 

Several of these changes are in genes that are linked to cardiovascular disease. 

However, it was not possible to determine whether these differences had contributed to the development of the disease, or if they live on as a memory of gene activation associated with the heart attack, the researchers said.

"We hope that our new results should contribute to increasing the knowledge of the importance of epigenetic in the clinical picture of a heart attack, which in the long run could lead to better drugs and treatments", Johansson added.

For the study, the team took blood samples from the northern Sweden population health study. Individuals with a history of a CVD were identified in the cohort. It included individuals with hypertension, myocardial infarction, stroke, thrombosis and cardiac arrhythmia. 

The results were published in the journal Human Molecular Genetics.

​New York, Sep 17 (IANS) Using NASA's Hubble space telescope, astronomers have captured the sharpest, most detailed observations of a comet breaking apart 108 million kilometres from Earth.

In a series of images taken over three days in January 2016, Hubble showed 25 fragments consisting of a mixture of ice and dust that are drifting away from the comet at a pace equivalent to the walking speed of an adult, said lead researcher David Jewitt from University of California, Los Angeles.

The images suggest that the roughly 4.5-billion-year-old comet, named 332P/Ikeya-Murakami, or comet 332P, may be spinning so fast that material is ejected from its surface.

The resulting debris is now scattered along a 4,828-km-long trail, said the study published online in Astrophysical Journal Letters.

These observations provide insight into the volatile behaviour of comets as they approach the sun and begin to vaporise, unleashing powerful forces.

"We know that comets sometimes disintegrate, but we don't know much about why or how," Jewitt said. 

"The trouble is that it happens quickly and without warning, so we don't have much chance to get useful data. With Hubble's fantastic resolution, not only do we see really tiny, faint bits of the comet, but we can watch them change from day to day. That has allowed us to make the best measurements ever obtained on such an object," Jewitt noted.

The three-day observations show that the comet shards brighten and dim as icy patches on their surfaces rotate into and out of sunlight. 

Their shapes change, too, as they break apart. The icy relics comprise about four percent of the parent comet and range in size from roughly 65 feet wide to 200 feet wide. 

They are separating at only a few kilometres per hour as they orbit the sun at more than 80,467 kms per hour.

The Hubble images show that the parent comet changes brightness frequently, completing a rotation every two to four hours. A visitor to the comet would see the sun rise and set in as little as an hour, Jewitt said.

The comet is much smaller than astronomers thought, measuring only 1,600 feet across, about the length of five football fields.

Comet 332P was discovered in November 2010, after it surged in brightness and was spotted by two Japanese astronomers.

London, Sep 16 (IANS) Children who engage in fantasy play are likely to score higher in creative thinking, a study has found.

The study found that it is possible that children who enjoy fantasy play are subsequently more creative, and it's equally possible that children who are more creative subsequently engage in more fantasy play. 

"This is because, theoretically, playing in make-believe worlds requires imagination to conceive of the world differently to its current reality, which is also necessary to think creatively," said lead researcher Louise Bunce from the Oxford Brookes University in Britian. 

The children's fantasy play involved pretending that mirrored real-life (e.g. having a tea party or pretending to be a teacher), events that were improbable in reality (e.g. fighting a lion and being unharmed or going to school in a helicopter) or impossible events (e.g. going to wizarding school or playing with an elf), the researchers said.

For the study, the team interviewed 70 children aged 4-8 years old to assess the extent to which their fantasy play involved.

The children also completed three creativity tasks. In the first task children had to think of as many things as possible that were red, in the second task they had to demonstrate as many ways as possible of moving across the room from A-B, then the third task asked them to draw a real and pretend person. 

In the first two tasks children received points for the number of responses they gave and how unique those responses were. Their drawings were rated for their level of creativity according to two judges.

Children who reported higher levels of fantasy play also received higher creativity scores across all three tasks.

"The results provide evidence that engaging in play that involves imagining increasingly unrealistic scenarios is associated with thinking more creatively, although at the moment we don't know the direction of this relationship," Bunce noted. 

"Parents and teachers could consider encouraging children to engage in fantasy play as one way to develop their creative thinking skills," the researchers suggested.

The findings were presented at the annual conference of the British Psychological Society's Developmental Psychology Section in Belfast, recently.

​Washington, Sep 16 (IANS) Lakes and snowmelt-fed streams on Mars formed much later than previously thought possible, new research has found.

The recently discovered lakes and streams appeared roughly a billion years after a well-documented, earlier era of wet conditions on ancient Mars, the study said. 

These results provide insight into the climate history of the Red Planet and suggest the surface conditions at this later time may also have been suitable for microbial life.

"We discovered valleys that carried water into lake basins," said Sharon Wilson of the Smithsonian Institution, Washington, and the University of Virginia, Charlottesville. 

"Several lake basins filled and overflowed, indicating there was a considerable amount of water on the landscape during this time," Wilson noted.

Wilson and colleagues found evidence of these features in Mars' northern Arabia Terra region by analysing images from the Context Camera and High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter and additional data from NASA's Mars Global Surveyor and the European Space Agency's Mars Express.

To bracket the time period when the fresh shallow valleys in Arabia Terra formed, scientists started with age estimates for 22 impact craters in the area. 

They assessed whether or not the valleys carved into the blankets of surrounding debris ejected from the craters, as an indicator of whether the valleys are older or younger than the craters. 

They concluded that this fairly wet period on Mars likely occurred between two and three billion years ago, long after it is generally thought that most of Mars' original atmosphere had been lost and most of the remaining water on the planet had frozen.

"A key goal for Mars exploration is to understand when and where liquid water was present in sufficient volume to alter the Martian surface and perhaps provide habitable environments," Mars Reconnaissance Orbiter Project Scientist Rich Zurek of NASA's Jet Propulsion Laboratory, Pasadena, California, said.

"This paper presents evidence for episodes of water modifying the surface on early Mars for possibly several hundred million years later than previously thought, with some implication that the water was emplaced by snow, not rain," Zurek said.

The findings were reported in the Journal of Geophysical Research, Planets.

New York, Sep 16 (IANS) Children differ substantially in their mathematical abilities. But, some may remain persistently bad at addition or subtraction as a result of abnormalities in the brain areas supporting procedural memory, a study that developed a theory of how developmental "math disability" occurs has revealed.

Procedural memory is a learning and memory system that is crucial for the automatisation of non-conscious skills, such as driving or grammar and depends on a network of brain structures, including the basal ganglia and regions in the frontal and parietal lobes, the study said.

"Various domains, including math, reading, and language, seems to depend on both procedural as well as declarative memory -- where conscious knowledge is learned," said Michael T. Ullman, Professor at the Georgetown University in the US.

"However, for some children with math disability, procedural memory may be dysfunctioned, so math skills may not get automatised," added lead author Tanya M. Evans, postdoctoral student at the Stanford University in the US. 

In fact, the aspects of math that tend to be automatised, such as arithmetic, are more problematic in children with math disability. 

Evidence suggests that when procedural memory is impaired, children may have math disability, dyslexia, or developmental language disorder, though declarative memory -- where conscious knowledge is learned -- often compensates to some extent," Ullman said.

The researchers said that their theory, called the procedural deficit hypothesis of math disability, "offers a powerful, brain-based approach for understanding the disorder, and could help guide future research." 

"We believe that understanding the role of memory systems in these disorders should lead to diagnostic advances and possible targets for interventions," Ullman noted, in the paper published in the journal Frontiers in Psychology. 

London, Sep 16 (IANS) Leaders often believe that they should show anger to make subordinates more compliant. Though angry leaders are perceived by others to wield more power, followers warm up more easily to those showing more vulnerable emotions, such as sadness, a study has found.

Emphasising that leaders should consciously reflect on the emotions they display, the study revealed that though angry leaders are considered to be more powerful than sad leaders, they still score lower on their leadership report cards.

"Subordinates form impressions of their leaders when they view their displays of emotion in negative work situations", said Tanja Schwarzmuller from the Technical University of Munich in Germany.

Although leaders might benefit from stressing their legitimate power, displays of anger could backfire as they cause subordinates to infer that their "boss" has strong coercive power but weak referent power -- the ability of a leader to influence followers by making them identify and sympathise with him or her. 

This referent power is also a crucial prerequisite for ensuring followers' loyalty and commitment, the study said.

"Although angry leaders might be considered more powerful in general, their resulting power seems to rest upon a weak foundation", Schwarzmuller observed.

For the study, the team conducted three sets of experiments. In the first two, groups of students or working adults assessed videos depicting angry and sad leaders. In the third, an online survey was conducted where the participants were shown relevant photographs.

As expected, angry leaders were viewed as having higher levels of different types of position power. This includes being legitimately instated over others, having the right to give or withhold rewards and coercive power to punish others.

Followers hence seem to think that leaders displaying anger, in comparison to leaders showing sadness, more strongly stress their legitimate position within the hierarchy of an organisation and the control over punishment and reward that is available to them. 

However, when it comes to personal power, leaders displaying sadness seem to appeal to followers more strongly, the researchers stated.

On the other hand, showing sadness too may prove to be problematic, as it often reduces a leader's legitimate power to punish - a power base that negatively affects leadership outcomes, the researchers concluded in the paper, published in the Journal of Business and Psychology.