Knowledge Update

​Washington, Dec 18 (IANS) Scientists have claimed to figured out how the world's biggest and most-valuable diamonds formed, media reported on Sunday.

In a study published this week in the US journal Science, the scientists said large gem-quality diamonds, like the world-famous Cullinan or Lesotho Promise, may be born in metallic liquid deep inside the Earth's mantle, Xinhua news agency reported.

The research team, led by Evan Smith of the Gemological Institute of America, reached the conclusion after examining so-called "offcuts" of massive diamonds, which are the pieces left over after the gem's facets are cut for maximum sparkle.

They found tiny metallic grains trapped inside in more than 30 exceptionally large stones, which are made up of a mixture of metallic iron and nickel, along with carbon, sulfur, methane, and hydrogen.

These inclusions led the researchers to conclude that these diamonds formed, like all diamonds, in the Earth's mantle, but they did so under conditions in which they were saturated by liquid metal.

Most diamonds formed at depths of 150 to 200 km under the continents and shoot to the surface in volcanic eruptions.

"Pure carbon crystallised in this mix of molten metallic liquid in Earth's deep mantle to form diamonds," the team explained in a statement.

"Small droplets of this metallic liquid were occasionally trapped within the diamonds as they grew," offering useful clues that may help "advance our understanding of Earth's deep mantle, hidden beneath tectonic plates and largely inaccessible for scientific observation," the statement added.

The findings may tell scientists about oxygen availability in different parts of the mantle.

Near the surface, the mantle chemistry is more oxidized, which scientists can tell from the presence of carbon in the form of carbon dioxide in magmas erupted in volcanoes.

"Previous experiments and theory predicted for many years that parts of the deep mantle below about 250 km depth contain small amounts of metallic iron and have limited available oxygen," Smith said.

Sydney, Dec 18 (IANS) People who leave school without a school certificate are more than twice as likely to have a heart attack as those with a university degree, researchers said.

New York, Dec 18 (IANS) Recreation activities in protected areas such as hiking impact wildlife mostly in negative ways, a study said.

Nature-based outdoor recreation is the most widespread human land use in protected areas and is permitted in more than 94 per cent of parks and reserves globally, the researchers said.

Hiking, a common form of outdoor recreation in protected areas, can create a negative impact by causing animals to flee, taking time away from feeding and expending valuable energy, the study said.

"People generally assume that recreation activities are compatible with conservation goals for protected areas," said lead author Courtney Larson from Colorado State University in the US.

"However, our review of the evidence across wildlife species and habitat types worldwide suggests otherwise," Larson noted.

Protected areas include national parks, wilderness areas, community conserved areas, nature reserves and privately-owned reserves.

The researchers reviewed 274 scientific articles published between 1981 and 2015 on the effects of recreation on a variety of animal species across all geographic areas and recreational activities.

More than 93 per cent of the articles reviewed, indicated at least one impact of recreation on animals, the majority of which or 59 per cent were negative.

Decreased species diversity, survival, and behavioural or physiological disturbance such as decreased foraging or increased stress are among the negative effects of outdoor recreation in protect areas, according to the study published in the journal PLOS ONE.

Surprisingly, studies of hiking and other non-motorised activities found negative effects on wildlife more frequently than studies of motorised activities.

However, since motorised activities generally cover a larger area, their influence on animals can also be widespread.

"They can also result in other environmental impacts, such as soil loss and vegetation disturbance," Larson said.

Toronto, Dec 18 (IANS) An international team of scientists has discovered a planetary system with a host star similar to Earth's sun, which could tell the history and connections between stars and their planets.

The team, which included researchers from the University of Chicago, said that unlike the artificial planet-destroying Death Star in the movie "Star Wars", this natural version could provide clues about how planetary systems evolve over time.

"It does not mean that the sun will 'eat' the Earth any time soon," Jacob Bean, co-author of an Astronomy and Astrophysics article on the research, said in a university statement.

"But our discovery provides an indication that violent histories may be common for planetary systems, including our own," Bean added.

Astronomers discovered the first planet orbiting a star other than the sun in 1995 and since then, more than two thousand exoplanets have been identified.

Rare among them are planets that orbit a star similar to Earth's sun. Due to their extreme similarity to the sun, these so-called solar twins are ideal targets for investigating the connections between stars and their planets.

It's tricky to draw conclusions from a single system, cautioned Megan Bedell, co-author of the research and the lead planet finder for the collaboration.

She said the team plans "to study more stars like this to see whether this is a common outcome of the planet formation process".

​London, Dec 17 (IANS) Drugs used to lower blood pressure can potentially block breast and pancreatic cancer invasion by inhibiting their cellular structures, say researchers.

The study discovered that calcium channel blockers -- currently used to treat hypertension -- can efficiently stop cancer cells move and invade surrounding tissue.

Identification of anti-hypertension drugs as potential therapeutics against breast and pancreatic cancer metastasis was a big surprise, said reseachers. 

The targets of these drugs were not known to be present in cancer cells and therefore no one had considered the possibility that these drugs might be effective against aggressive cancer types, said Johanna Ivaska at the University of Turku in Finland. 

The findings showed that aggressively spreading cancer cells express a protein called Myosin-10 which drives cancer cell motility.

Myosin-10 expressing cancers have a large number of structures called filopodia, or sticky finger-like structures the cancer cells extend to sense their environment and to navigate - imagine a walking blind spider, explained Guillaume Jacquemet, postdoctoral researcher at University of Turku. 

The calcium channel blockers target specifically these sticky fingers rendering them inactive, thus efficiently blocking cancer cell movement. This suggest that they might be effective drugs against cancer metastasis, the researchers said.

The findings were published in the journal Nature Communications.

​London, Dec 17 (IANS) Dropping cholesterol to the lowest level possible -- to levels similar to those we were born with -- may help reduce the risk of heart attack, stroke or fatal heart disease by nearly one third, a study has found.

Reducing cholesterol as low as possible is safe and more beneficial than the current normal levels -- 100 mg/dL (deci-litres) or below -- achieved with existing drugs such as statins, the study said.

However, participants in the study used a additional novel drug called alirocumab -- for patients whose cholesterol levels are not sufficiently lowered by statins.

The combined effect of the new drug and the statin therapy in the trials meant that patients reached very low cholesterol - lower than 50 mg/dL -- comparable to the levels we are born with.

For every 39 mg/dL reduction in low density lipoprotein (LDL) cholesterol -- or 'bad' cholesterol -- responsible for clogging arteries, the risk of heart attack -- stroke, angina or death from heart disease -- decreased by 24 per cent, the researchers observed.

"Experts have been uncertain whether very low cholesterol levels are harmful, or beneficial. This study suggests not only are they safe, but they also reduced risk of heart disease, heart attack and stroke," said lead author Kausik Ray, Professor at Imperial College London in Britain.

This lowest cholesterol levels is only achievable in adulthood, through medication, as well as lifestyle changes like healthy food and exercise, the researchers suggested.

For the study, published in the journal Circulation, the team analysed data from 10 trials, involving around 5,000 patients, diagnosed with high cholesterol.

​London, Dec 17 (IANS) Researchers have identified a molecule that impairs the lungs' ability to repair damages on their own after developing chronic obstructive pulmonary disease (COPD) that makes it makes it hard for sufferers to breathe.

The first indication of COPD is usually a chronic cough. As the disease progresses, the airways narrow and often pulmonary emphysema develops. This indicates irreversible expansion and damage to the alveoli, or air sacks. 

"The body is no longer able to repair the destroyed structures," explained Melanie Konigshoff from Helmholtz Zentrum Munchen -- German Research Centre for Environmental Health.

"In our current work we have been able to show that COPD results in a change in the messengers that lung cells use to communicate with one another," Konigshoff added.

In the study published Journal of Experimental Medicine, the researchers blamed the increased production of the molecule Wnt5a for this problem.

"Our working hypothesis was that the relationship between different Wnt messengers is no longer balanced in COPD," the study's first author Hoeke Baarsma from Helmholtz Zentrum Munchen.

"In both the pre-clinical model and the tissue samples from patients, we found that in COPD tissue particularly the non-canonical Wnt5a molecule is increased and occurs in a modified form," Baarsma added.

Stimuli that typically cause a reaction in COPD, such as cigarette smoke, additionally lead to increased production of Wnt5a and consequently to impaired lung regeneration, the researchers said.

The findings could lead to new therapeutic approaches to treat the disease.

​Tokyo, Dec 17 (IANS) Japanese scientists have in a breakthrough developed a new technique that can manipulate people's brain activity to boosts their self-confidence, a finding that opens the potential treatments for conditions such as post-traumatic-stress-disorder (PTSD) and phobias.

The new technique called 'Decoded Neurofeedback' identifies brain activity linked to confidence and then amplifies it to a high confidence state.

For patients with PTSD and Alzheimer's disease self confidence is an important aspect, which is often complicated by patients thinking negatively of their own capacities. 

In the study, using this technique, participants' brains were scanned to monitor and detect the occurrence of specific complex patterns of activity corresponding to high confidence states, while they performed a simple perceptual task. 

Whenever the pattern of high confidence was detected, participants received a small monetary reward.

This experiment allowed researchers to directly boost one's own confidence unconsciously, i.e. participants were unaware that such manipulation took place. 

Importantly, the effect could be reversed, as confidence could also be decreased.

"By continuously pairing the occurrence of the highly confident state with a reward - a small amount of money - in real-time, we were able to do just that: when participants had to rate their confidence in the perceptual task at the end of the training, their were consistently more confident," Aurelio Cortese from the Advanced Telecommunications Research Institute International in Kyoto, Japan. 

The study was published in the journal Nature Human Behavior.

London, Dec 17 (IANS) In a finding that could put an end to the use of medication in the treatment of social anxiety disorder, researchers have shown that structured talk therapy or cognitive alone has the potential to cure social phobia.

In treating patients with social anxiety disorder, cognitive therapy on its own has a much better effect over the long term than just drugs or a combination of the two, said the study.

"This is the most effective treatment ever for this patient group. Treatment of mental illness often isn't as effective as treating a bone fracture, but here we've shown that treatment of psychiatric disorders can be equally effective," said lead researcher Hans Nordahl, Professor at the Norwegian University of Science and Technology (NTNU).

Social anxiety is not a diagnosis, but a symptom that a lot of people struggle with. For example, talking or being funny on command in front of a large audience can trigger this symptom.

Until now, a combination of cognitive therapy and medication was thought to be the most effective treatment for these patients. 

In this study involving over 100 patients -- published in the journal Psychotherapy and Psychosomatics -- nearly 85 per cent of the study participants significantly improved or became completely healthy using only cognitive therapy.

"A lot of doctors and hospitals combine medications - like the famous "happy pill" - with talk therapy when they treat this patient group. It works well in patients with depressive disorders, but it actually has the opposite effect in individuals with social anxiety disorders. Not many health care professionals are aware of this," Nordahl noted.

"Happy pills," like selective serotonin reuptake inhibitors (SSRIs), may have strong physical side effects. 

The researchers noted that when patients have been on medications for some time and want to reduce them, the bodily feelings associated with social phobia, like shivering, flushing and dizziness in social situations tend to return. 

Patients often end up in a state of acute social anxiety again.

"The medication camouflages a very important patient discovery: that by learning effective techniques, they have the ability to handle their anxiety themselves," Nordahl said.

​New York, Dec 17 (IANS) Antiretroviral drugs have been life-changing therapies for HIV patients, but they can have significant side effects including neuronal degeneration, which can be manifested as forgetfulness, confusion and behavioural and motor changes, says a study.

Certain protease inhibitors, among the most effective HIV drugs, lead to the production of the peptide beta amyloid, often associated with Alzheimer's disease, the study found.

"Protease inhibitors are very effective antiviral therapies, but they do have inherent toxicities," said senior author on the study Kelly Jordan-Sciutto, Professor at University of Pennsylvania School of Dental Medicine in the US.

The drugs prompt an increase in levels of the enzyme that cleaves the amyloid precursor protein, APP, to produce beta amyloid, which is responsible for the damage to neurons.

Notably, inhibiting that enzyme, called BACE1, protected human and rodent brain cells from harm, suggesting that targetting this mechanism with a new drug could minimise damage to neurons in patients on antiretroviral therapies.

"Our findings may cause us to rethink how we're using these drugs and even consider developing an adjunctive therapy to reduce some of these negative effects," Jordan-Sciutto noted.

To determine whether and how neuronal damage arises from drug treatment and to ascertain the enzyme BACE1's role, the team investigated the effects of protease inhibitors in two animal models, then probed the mechanism of action in cells in culture.

The findings appeared in the American Journal of Pathology.