Knowledge Update

New York, Feb 24 (IANS) Fructose -- simple sugar found in fruits, vegetables, table sugar, and many processed foods -- is converted in the human brain from glucose, according to a new study.

Previous studies have established that excess consumption of fructose contributes to high blood sugar and chronic diseases like obesity. But it was not known whether fructose was produced in the brain or crossed over from the bloodstream.

"In this study, we show for the first time that fructose can be produced in the human brain," said first author Janice Hwang, Assistant Professor at Yale University, in the US.

The study showed that high concentration of fructose in the brain was due to a metabolic pathway called the polyol pathway that converts glucose to fructose.

"By showing that fructose in the brain is not simply due to dietary consumption of fructose, we've shown fructose can be generated from any sugar you eat. It adds another dimension into understanding fructose's effects on the brain," Hwang added, in the paper published in the journal JCI Insight. 

Glucose in the brain sends signals of fullness, but that is not the case with fructose. The conversion of glucose to fructose in the brain also occurs in other parts of the body.

This polyol pathway may be one other mechanism by which high blood sugar can exert its adverse effects.

The finding also raises questions about fructose's effects on the brain and eating behaviour, Hwang said.

For the study, the team gave eight healthy, lean individuals infusions of glucose over a four-hour period, where the sugar concentrations in the brains and blood of the participants were assessed.

The results revealed that cerebral fructose levels rose significantly in response to a glucose infusion, with minimal changes in fructose levels in the blood

​New York, Feb 24 (IANS) Astronomers have spotted an enormous, glowing blob of gas in the distant universe, with no obvious source of power for the light it is emitting.

Called an "enormous Lyman-alpha nebula" (ELAN), it is the brightest and among the largest of these rare objects, only a handful of which have been observed, the researchers said.

The newly discovered nebula was found at a distance of 10 billion light years in the middle of a region with an extraordinary concentration of galaxies. 

Researchers found this massive overdensity of early galaxies, called a "protocluster," through a novel survey project led by Zheng Cai, Hubble postdoctoral fellow at University of California, Santa Cruz in the US.

"Our survey was not trying to find nebulae. We're looking for the most overdense environments in the early universe, the big cities where there are lots of galaxies," said Cai, who is first author of a paper on the discovery to be published in the Astrophysical Journal.

"We found this enormous nebula in the middle of the protocluster, near the peak density," Cai said.

ELANs are huge blobs of gas surrounding and extending between galaxies in the intergalactic medium. 

They are thought to be parts of the network of filaments connecting galaxies in a vast cosmic web. 

Previously discovered ELANs are likely illuminated by the intense radiation from quasars, but it is not clear what is causing the hydrogen gas in the newly discovered nebula to emit Lyman-alpha radiation (a characteristic wavelength of light absorbed and emitted by hydrogen atoms), the researchers said.

The newly discovered ELAN is known as MAMMOTH-1.

"It's a terrifically energetic phenomenon without an obvious power source," said study co-author J. Xavier Prochaska, Professor at University of California, Santa Cruz.

​London, Feb 24 (IANS) Have a sweet tooth? Beware, you may be at risk of developing Alzheimer's disease, as a study has found a specific molecular link between abnormally high blood sugar levels, or hyperglycaemia -- a key characteristic of diabetes and obesity -- and Alzheimer's disease.

The findings showed that excess glucose damages a vital enzyme involved with inflammation response to the early stages of Alzheimer's and that is the reason behind diabetes patients having an increased risk of developing the disease compared to healthy individuals.

"Excess sugar is well known to be bad for us when it comes to diabetes and obesity, but this potential link with Alzheimer's disease is yet another reason that we should be controlling sugar intake in our diets," said Omar Kassaar, from the University of Bath in Britain.

For the study, published in the journal Scientific Reports, the team studied brain samples from people with and without Alzheimer's using a sensitive technique to detect glycation -- the bonding of a sugar molecule.

The results showed that in the early stages of Alzheimer's, glycation damages an enzyme called MIF (macrophage migration inhibitory factor) which plays a role in immune response and insulin regulation.

MIF is involved in the build-up of abnormal proteins in the brain during Alzheimer's. This inhibition and reduction of MIF activity caused by glycation could be the "tipping point" in disease progression, the researchers said.

"Normally MIF would be part of the immune response to the build-up of abnormal proteins in the brain and we think that because sugar damage reduces some MIF functions and completely inhibits others that this could be a tipping point that allows Alzheimer's to develop," explained Jean van den Elsen, Professor at the University of Bath.

The study may be vital to developing a chronology of how Alzheimer's progresses and help identify those at risk of Alzheimer's and lead to new treatments or ways to prevent the disease, the researchers noted.

Sydney, Feb 24 (IANS) Sweating depends on body size, weight and not on gender, meaning that larger individuals sweat more than smaller ones during exercises in warm and tolerable conditions, a study has found, negating the conventional belief that gender influences sweat.

The body cools itself down in two main ways: Sweating and increasing circulation to the skin's surface. Body shape and size dictates which of these two is relied upon for heat loss, the researchers said. 

"Gender has long been thought to influence sweating and skin blood flow during heat stress. We found that these heat loss responses are, in fact, gender independent during exercise in conditions where the body can successfully regulate its temperature," said lead author Sean Notley from the University of Wollongong in Australia.

The study found that smaller males and females with more surface area per kg of body mass are more dependent on heat loss through increasing circulation and less dependent upon sweating.

For the study, published in the journal Experimental Physiology, the team looked at skin blood flow and sweating responses in 36 men and 24 women.

They performed two trials -- one of light exercise and the other of moderate -- at 28 degrees Celsius and 36 per cent humidity. 

These are conditions where the body is able to mitigate the additional heat produced during exercise and prevent further rises in body temperature by increasing sweating and blood flow to the skin.

The results showed that the body temperature changes were same in all participants within each trial regardless of the gender.

New York, Feb 24 (IANS) Nature's clock is running fast in the Arctic, thanks to climate change. Due to diminishing sea ice cover, spring is coming sooner to some plant species in the low Arctic of Greenland, while other species are delaying their emergence amid warming winters, says a study.

The timing of seasonal events, such as first spring growth, flower bud formation and blooming make up a plant's phenology -- the window of time it has to grow, produce offspring, and express its life history. It can be called "nature's clock."

While how early a plant emerges from its winter slumber depends on the species, the study, published in the journal Biology Letters, demonstrates that the Arctic landscape is changing rapidly. 

Such changes carry implications for the ecological structure of the region for years to come.

"The Arctic is really dynamic, and it's changing in a direction that won't be recognisable as the same Arctic to those of us who have been working there for decades," said lead author Eric Post, a polar ecologist at the University of California - Davis in the US.

"The picture is definitely being reorganised," Post said.

The study covered 12 years of observations at a West Greenland field site, about 240 km inland from the Davis Strait. 

The site is near Russell Glacier, a dynamic front protruding from the massive inland ice sheet that covers most of the island. 

Each year from early May to late June, researchers looked daily for the first signs of growth in plots enclosing individual plant species.

They found that warming winters and springs associated with declining arctic sea ice cover created a mixture of speed demons, slowpokes and those in between. 

One racehorse of a sedge species now springs out of the proverbial gate a full 26 days earlier than it did a decade ago. 

This was the greatest increase in the timing of emergence the researchers had seen on record in the Arctic.

"When we started studying this, I never would have imagined we'd be talking about a 26-day per decade rate of advance," Post said.

"That's almost an entire growing season. That's an eye-opening rate of change," Post said.

​Washington, Feb 23 (IANS) In a remarkable step towards answering the question "Are we alone in the universe", astronomers have spotted a nearby star with seven Earth-size planets which could harbour liquid water, key to life as we know it, NASA said.

At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. 

All of these seven planets could have liquid water under the right atmospheric conditions, but the chances are highest with three of the plants which are located in the habitable zone, according to the researchers.

"This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life," said Thomas Zurbuchen, Associate Administrator of NASA's Science Mission Directorate in Washington. 

Because they are located outside of our solar system, these planets are scientifically known as exoplanets.

This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. 

"The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star," said Michael Gillon, lead author of the paper and the principal investigator of the TRAPPIST exoplanet survey at the University of Liege, Belgium. 

"It is also the best target yet for studying the atmospheres of potentially habitable, Earth-size worlds," Gillon said.

In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system. 

Assisted by several ground-based telescopes, including the European Southern Observatory's Very Large Telescope, NASA's Spitzer space telescope confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.

Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them, allowing their density to be estimated.

Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky, according to the new results published on Wednesday in the journal Nature

Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surface. 

The mass of the seventh and farthest exoplanet has not yet been estimated. But scientists believe it could be an icy, "snowball-like" world, but further observations are needed.

The discovery of the seven exoplanets sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system. 

In contrast to our sun, the TRAPPIST-1 star -- classified as an ultra-cool dwarf -- is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. 

All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun.

The planets also are very close to each other. If a person was standing on one of the planet's surface, they could gaze up and potentially see geological features or clouds of neighbouring worlds, which would sometimes appear larger than the moon in the Earth's sky, NASA said.

London, Feb 23 (IANS) Would you like to know what does the future hold for you? If yes, you may have only a few company. A new study shows that given the chance to see into the future, most people would rather not know what life has in store for them -- whether it brings good things or bad.

"In Greek mythology, Cassandra, daughter of the King of Troy, had the power to foresee the future. But, she was also cursed and no one believed her prophecies," said the study's lead author Gerd Gigerenzer from Max Planck Institute for Human Development in in Berlin, Germany. 

"In our study, we've found that people would rather decline the powers that made Cassandra famous, in an effort to forgo the suffering that knowing the future may cause, avoid regret and also maintain the enjoyment of suspense that pleasurable events provide," Gigerenzer said.

The findings, published in the journal Psychological Review, are based on two studies involving more than 2,000 adults in Germany and Spain.

The study found that 85 to 90 per cent of people would not want to know about upcoming negative events, and 40 to 70 percent preferred to remain ignorant of upcoming positive events. 

Only one percent of participants consistently wanted to know what the future held. 

The researchers also found that people who prefer not to know the future are more risk averse and more frequently buy life and legal insurance than those who want to know the future. 

This suggests that those who choose to be ignorant anticipate regret, Gigerenzer said. 

The length of time until an event would occur also played a role. Deliberate ignorance was more likely the nearer the event. 

For example, older adults were less likely than younger adults to want to know when they or their partner would die, and the cause of death. 

"Not wanting to know appears counter-intuitive and may raise eyebrows, but deliberate ignorance, as we've shown here, doesn't just exist; it is a widespread state of mind," Gigerenzer said.

​London, Feb 23 (IANS) Injecting a particular weight loss drug in combination with diet and exercise may reduce risk of diabetes by 80 per cent in individuals with obesity and prediabetes, a study said.

The results of the international clinical trial showed that liraglutide promoted weight loss by interacting with the areas of the brain that control appetite and energy intake.

Published in the journal The Lancet, the results showed that three years of continuous treatment with once-daily liraglutide 3.0 mg, in combination with diet and increased physical activity, reduced the risk of developing the Type 2 diabetes.

In fact, in 60 per cent of those patients with borderline diabetes the condition was reversed, and patients returned to healthy blood sugar levels, the study showed.

"Liraglutide promotes weight loss by activating brain areas that control appetite and eating, so that people feel fuller sooner after meals and their food intake is reduced," said Carel le Roux, Professor at Imperial College London. 

"Although liraglutide's role in weight loss is well known, this is the first time it has been shown to essentially reverse prediabetes and prevent diabetes, albeit with the help of diet and exercise," le Roux added.

Of the patients who did go on to develop diabetes, those who were given liraglutide, took nearly three times longer to develop the disease. 

In addition, liraglutide also helped patients lose seven per cent body weight compared to only two per cent in the placebo group, the researchers said.

"Liraglutide 3.0 mg can provide us with a new therapeutic approach for patients with obesity and prediabetes," explained John Wilding, Professor at the University of Liverpool.

For this obesity and prediabetes trial, the team followed 2,254 adults with prediabetes at 191 research sites in 27 countries worldwide. 

The participants were randomly allocated either liraglutide 3.0 mg or a placebo delivered by injection under the skin once daily for 160 weeks. 

They were also placed on a reduced calorie diet and advised to increase their physical activity.

​Washington, Feb 23 (IANS) In a major boost to the search for alien life outside our solar system, astronomers have spotted the first known system of seven Earth-size planets around a single star, NASA said.

All of these seven planets could have liquid water -- key to life as we know it -- under the right atmospheric conditions, but the chances are highest with three of the plants which are located in the habitable zone, according to the researchers.

"This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life," said Thomas Zurbuchen, Associate Administrator of NASA's Science Mission Directorate in Washington. 

At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. 

Because they are located outside of our solar system, these planets are scientifically known as exoplanets.

This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. 

In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system. 

Assisted by several ground-based telescopes, including the European Southern Observatory's Very Large Telescope, NASA's Spitzer space telescope confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.

Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them, allowing their density to be estimated.

Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky, according to the new results published on Wednesday in the journal Nature

Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces. 

The mass of the seventh and farthest exoplanet has not yet been estimated. But scientists believe it could be an icy, "snowball-like" world, but further observations are needed.

The discovery of the seven exoplanets sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system. 

"The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star," said Michael Gillon, lead author of the paper and the principal investigator of the TRAPPIST exoplanet survey at the University of Liege, Belgium. 

"It is also the best target yet for studying the atmospheres of potentially habitable, Earth-size worlds," Gillon said.

In contrast to our sun, the TRAPPIST-1 star - classified as an ultra-cool dwarf - is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. 

All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun, the researchers said.

​Canberra, Feb 23 (IANS) Australian engineers have created an advanced microscope using a beefed-up "barcode scanner", which they believe will help doctors better analyse complex medical conditions such as cancer.

Engineers from the Australian National University (ANU) said the microscope can film moving blood cells and neurons in living animals, something which they say will help doctors and scientists to research complex blood disorders, Xinhua news agency reported.

Steve Lee, a biomedical optics engineer at the ANU, said the microscope used technology similar to retail barcode scanners and office laser printers.

"Scientists can use our new microscope to analyse complex medical problems ranging from blood disorders and cancer to neurological disorders," Lee said in a statement released on Thursday.

"The microscope can speed up or slow down to capture the slow moving cells in a blood stream or live neurons firing rapidly in the brain, making it much more flexible than other microscopes on the market."

In traditional, "supermarket-style", barcode scanners, a laser beam bounces off a spinning polygon mirror, allowing it to scan across a sample very quickly. The scanner detects the unique sequence of each barcode to identify each certain product.

Lee said the ANU microscope used a more powerful laser beam as the light source and up to 36 mirror facets to "scan the laser beam across the biological sample in a few thousandths of a second".

"We achieve the same imaging resolution of conventional scanning microscopes on the market but at double the speed," he said.

"The innovation here is that we modernised the polygon mirror microscopy system with advanced electronics and software controls to enable real-time imaging applications, with up to 800 frames per second."