Knowledge Update

​New York, March 2 (IANS) Researchers have found a way to activate the immune system's natural cancer-killing T-cells and cause tumours to shrink in mice with colon cancer.

The intervention essentially trains the immune system to recognise and attack the tumour, and to protect against additional tumour formation - a significant issue in colon cancer, said corresponding author Ajay Maker, Associate Professor at University of Illinois College of Medicine in Chicago, US.

In the study, published in the journal Cancer Research, the researchers reported that increasing expression of a chemical cytokine called LIGHT in mice with colon cancer activated the immune system's natural cancer-killing T-cells and caused primary tumours in the liver to shrink.

LIGHT is an immune-stimulating chemical messenger previously found to have low levels of expression in patients with colon cancer metastases.

"For most patients with colon cancer that has spread to the liver, current treatments are palliative and not curative," Maker said.

"And while studies have suggested that immunotherapy may be a promising approach for advanced cancers, the use of such treatments for advanced gastrointestinal metastases have not yet been very successful," Maker said.

This study is exciting because it looks at an immunotherapy intervention for a previously unresponsive gastrointestinal cancer, Maker said.

For the study, the researchers established colon cancer tumors in a mouse model, in which the animals had an intact and unedited immune system. 

Once tumours were sizable, the mice were randomised into two groups - one group had the cytokine LIGHT turned on in the tumours, and the other served as a control group for comparison.

Tumours exposed to LIGHT showed an influx of T-cells that resulted in rapid and sustained diminishment in size, even after expression of the cytokine stopped. 

In cases where the tumour spread to liver, expression of LIGHT similarly provoked a potent immune response that resulted in a significant decrease in tumour burden.

"We demonstrated that delivery of a therapeutic immune-stimulating cytokine caused T-cells to traffic to tumours and to become activated tumor-killing cells," Maker said. 

Johannesburg, March 2 (IANS) African elephants -- the largest land animal -- sleep for just an average of two hours a day and regularly survive for nearly two days without sleep, a study has found.

Previous studies of sleep in captive elephants have shown that they sleep for four to six hours per day. 

However, "in their natural habitat, wild, free-ranging elephants sleep only for two hours per day, the least amount of sleep of any mammal studied to date, but this appears to be related to their large body size," said Paul Manger from the University of Witwatersrand in South Africa. 

For the study, published in the journal PLOS ONE, the team monitored two free-roaming African elephant matriarchs in Chobe National Park in Botswana for 35 days. The elephants were implanted with an actiwatch, in the trunk to track sleep accurately and a collar with a gyroscope to track sleeping position.

The researchers found that the elephants slept an average of two hours a day -- the shortest known sleep time of any land mammal. 

On several days, the elephants were found to survive without sleep for up to 46 hours. 

They travelled long distances of around 30 km during these periods, possibly due to disturbances such as lions or poachers and were found to sleep lying down only every few nights. 

"In addition, it appears that elephants only go into REM (rapid eye movement), or dreaming, sleep every three to four days, which makes elephant sleep unique," Manger added.

Beijing, March 2 (IANS) China will launch a space station core module in 2018 as the first step in completing the country's first space outpost, Xinhua news agency reported.

The core module of the space station, named "Tianhe-1" according to previous reports, will be launched on board a new-generation Long March-5 heavyweight carrier rocket, said Bao Weimin, director with CASC and a member of the National Committee of the Chinese People's Political Consultative Conference (CPPCC).

It will be followed by a series of launches for other components of the space station, including two space labs, which will dock with the core module while in space, in the next four years or so, he said, adding that the space station will be completed around 2022.

Assembly of the core module has already been completed and tests are currently under way, said Bao, who is in Beijing for the annual session of China's top political advisory body.

Earlier reports said the new Chinese space station will initially be much smaller than the current International Space Station (ISS), which weighs 420 tonnes, but could be expanded for future scientific research and international cooperation.

With the ISS set to retire in 2024, the Chinese space station will offer a promising alternative, and China will be the only country with a permanent space station.

Bao said the Chinese outpost will function in orbit for "dozens of years", and that it had been specially designed to be able to handle space debris.

"For the big pieces (of space debris), we could conduct evasive manoeuvres, and for those measuring less than 10 cm in size, we just take the hit," Bao said, adding that all key parts of the space station will be serviceable and replaceable.

He went on to say that the next five years will see some exciting advances in China's space programme.

London, March 1 (IANS) Frogs have the unique ability to see colour even when it is so dark that we are not able to see anything at all, new research has found.

The findings, published in the journal Philosophical Transactions of the Royal Society B, suggest that the night vision of frogs and toads may be superior to that of all other animals. 

"It's amazing that these animals can actually see colour in extreme darkness, down to the absolute threshold of the visual system. These results were unexpected," said one of the study authors Almut Kelber, Professor at Lund University in Sweden.

Most vertebrates, including humans, have two types of visual cells located in the retina, namely cones and rods. 

The cones enable us to see colour, but they usually require a lot of light and, therefore, stop working when it gets dark, in which case the rods take over so that we can at least find our way home, although in black and white.

In toads and frogs, the rods are a bit special. 

It was previously known that toads and frogs are unique in having rods with two different sensitivities. 

This has not been found in other vertebrates, and it is also the reason why researchers have long suspected that frogs and toads might be able to see colour also in low-light conditions.

The new study proves this to be true, and the results exceeded all expectations.

The researchers studied to what extent frogs and toads use their colour vision when searching for a mate or hunting for food. 

The results showed that the animals stop using their colour information fairly early when it comes to finding someone with whom to mate, whereas they continue to take advantage of their colour vision to select food in such low-light conditions that humans lose their ability to see colour.

"We have previously shown moths and geckos are also able to see colour in inferior light conditions compared to humans. However, frogs apparently have a unique ability to see colour in the dark," Kelber said.

New York, March 1 (IANS) Researchers have identified 35 mosquito species, including 26 previously unsuspected ones, that could possibly transmit the deadly Zika virus.

"The biggest take-home message is that these are the species that we need to prioritise," said lead author Michelle Evans from University of Georgia in the US. 

Zika virus is currently known to be transmitted to people primarily through the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus). 

These are the same mosquitoes that spread dengue and chikungunya viruses, according to US Centers for Disease Control and Prevention.

The researchers said that targetting Zika's potential vectors -- species that can transmit the virus from one host to another -- is an urgent need, given its explosive spread and the devastating health effects associated with it.

The new predictive model, detailed in the journal eLife, could streamline the initial step of pinpointing Zika vectors.

"What we've done is to draw up a list of potential vector candidates based on the associations with viruses that they've had in the past as well as other traits that are specific to that species," study co-author Courtney Murdock, Assistant Professor at University of Georgia, said.

"That allows us to have a predictive framework to effectively get a list of candidate species without having to search blindly," Murdock said.

The researchers developed their model using machine learning, a form of artificial intelligence that is particularly useful for finding patterns in large, complicated data sets. 

Data used in the model consisted of information about the traits of flaviviruses -- the family that includes Zika, yellow fever and dengue -- and all the mosquito species that have ever been associated with them.

​Washington, March 1 (IANS) A trip past the sun may have selectively altered the production of one form of water in a comet known as Lovejoy -- an effect not seen by astronomers before, a new NASA study suggests.

The findings could shed new light on how much comets might have contributed to Earth's water compared to asteroids.

"Comets can be quite active and sometimes quite dynamic, especially when they are in the inner solar system, closer to the sun," said co-author of the study Michael Mumma, Director of NASA's Goddard Center for Astrobiology. 

NASA scientists observed the Oort cloud comet C/2014 Q2, also called Lovejoy, when it passed near Earth in early 2015. 

Through NASA's partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed the comet at infrared wavelengths a few days after Lovejoy passed its perihelion - or closest point to the sun.

The team focused on Lovejoy's water, simultaneously measuring the release of H2O along with production of a heavier form of water, HDO. 

Water molecules consist of two hydrogen atoms and one oxygen atom. A hydrogen atom has one proton, but when it also includes a neutron, that heavier hydrogen isotope is called deuterium, or the "D" in HDO. 

From these measurements, the researchers calculated the D-to-H ratio -- a chemical fingerprint that provides clues about exactly where comets (or asteroids) formed within the cloud of material that surrounded the young sun in the early days of the solar system.

Researchers also use the D-to-H value to try to understand how much of Earth's water may have come from comets versus asteroids.

The scientists compared their findings from the Keck observations with another team's observations made before the comet reached perihelion, using both space- and ground-based telescopes, and found an unexpected difference.

After perihelion, the output of HDO was two to three times higher, while the output of H2O remained essentially constant, showed the findings published online in the Astrophysical Journal Letters.

This meant that the D-to-H ratio was two to three times higher than the values reported earlier.

"If the D-to-H value changes with time, it would be misleading to assume that comets contributed only a small fraction of Earth's water compared to asteroids," lead author of the study Lucas Paganini, a researcher with the Goddard Center for Astrobiology, said.

New York, Feb 28 (IANS) Exoplanets with hydrogen pouring from volcanic sources may have a warmer surface and provide a better target for scientists to find signs of life outside our home planet, says a study.

"On frozen planets, any potential life would be buried under layers of ice, which would make it really hard to spot with telescopes," said lead author Ramses Ramirez from Cornell University in the US.

"But if the surface is warm enough -- thanks to volcanic hydrogen and atmospheric warming -- you could have life on the surface, generating a slew of detectable signatures," Ramirez said.

Combining the greenhouse warming effect from hydrogen, water and carbon dioxide on planets sprinkled throughout the cosmos, distant stars could expand their habitable zones by 30 to 60 per cent, according to this new research published in the Astrophysical Journal Letters.

"Where we thought you would only find icy wastelands, planets can be nice and warm - as long as volcanoes are in view," Lisa Kaltenegger, Professor at Cornell University, said. 

The idea that hydrogen can warm a planet is not new, but an Earth-like planet cannot hold onto its hydrogen for more than a few million years. Volcanoes change the concept. 

"You get a nice big warming effect from volcanic hydrogen, which is sustainable as long as the volcanoes are intense enough," said Ramirez, who suggested the possibility that these planets may sustain detectable life on their surface.

A very light gas, hydrogen also "puffs up" planetary atmospheres, which will likely help scientists detect signs of life. 

"Adding hydrogen to the air of an exoplanet is a good thing if you're an astronomer trying to observe potential life from a telescope or a space mission. It increases your signal, making it easier to spot the makeup of the atmosphere as compared to planets without hydrogen," Ramirez said.

In our solar system, the habitable zone extends to 1.67 times the Earth-sun distance, just beyond the orbit of Mars. 

With volcanically sourced hydrogen on planets, this could extend the solar system's habitable zone reach to 2.4 times the Earth-sun distance -- about where the asteroid belt is located between Mars and Jupiter. 

This research places a lot of planets that scientists previously thought to be too cold to support detectable life back into play.

"We just increased the width of the habitable zone by about half, adding a lot more planets to our 'search here' target list," Ramirez said.

​London, Feb 28 (IANS) If you are using a pacemaker to regulate your heartbeat, be careful about the proximity to your body of everyday household appliances and electrical tools as these may affect the functioning of the device, warns new research.

A pacemaker is a small device that is placed in the chest or abdomen to help control abnormal heart rhythms. This device uses low-energy electrical pulses to prompt the heart to beat at a normal rate and is used to treat problems relating to the rate or rhythm of the heartbeat.

The findings showed that pacemakers are susceptible to electric and magnetic fields (EMF) generated from powerlines, household appliances, electrical tools and entertainment electronics, in particular when programmed to maximum sensitivity or so-called unipolar sensing mode. 

This EMF interference, depending on factors such as the settings of the implant or strength of the field source with pacemakers, can result in bradycardia, or a slow heart rate. 

"Electromagnetic interferences with pacemakers in everyday life can cause harmful interferences," said Andreas Napp, cardiologist at RWTH Aachen University Hospital in Germany.

In many cases, holding the appliance, tool or other EMF source at a forearm's length distance -- greater than 12 inches -- limits the risk of electromagnetic interference. 

Thus, "in occupational environments, such as the manufacturing industry, an individual risk assessment for workers with a pacemaker is required due to the presence of a strong EMF," Napp added, in the paper appearing in the journal Circulation.

However, using dedicated device programming can effectively measure to reduce the individual risk of interference. For example, doctors can reprogramme pacemakers to a lower sensitivity to reduce EMF susceptibility, Napp said.

For the study, the team tested under different conditions the impacts of EMF exposure on 119 patients with pacemakers.

New York, Feb 28 (IANS) Dogs and two-year-old children show similar patterns in social intelligence, much more than one of our closest relatives -- chimpanzees, says a study.

The researchers looked at how two-year-olds, dogs and chimpanzees performed on comparable tests designed to measure various types of cognition. 

While chimpanzees performed well on tests involving their physical environment and spatial reasoning, they did not do as well when it came to tests of cooperative communication skills, such as the ability to follow a pointing finger or human gaze.

Dogs and children outperformed chimpanzees on cooperative communication tasks, and researchers observed similar patterns of variation in performance between individual dogs and between individual children.

"What we found is that there's this pattern, where dogs who are good at one of these social things tend to be good at lots of the related social things, and that's the same thing you find in kids, but you don't find it in chimpanzees," said Evan MacLean, Director of the Arizona Canine Cognition Center at the University of Arizona in the US.

The findings, published in the journal Animal Behaviour, could help scientists better understand how humans evolved socially.

One explanation for the similarities between dogs and humans is that the two species may have evolved under similar pressures that favoured "survival of the friendliest", with benefits and rewards for more cooperative social behaviour.

"Our working hypothesis is that dogs and humans probably evolved some of these skills as a result of similar evolutionary processes, so probably some things that happened in human evolution were very similar to processes that happened in dog domestication," MacLean said. 

"So, potentially, by studying dogs and domestication we can learn something about human evolution," he added.

The research could even have the potential to help researchers better understand human disabilities, such as autism, that may involve deficits in social skills, MacLean said.

New York, Feb 28 (IANS) Shortly after te Earth formed and began to cool, the planet's first outer layer was a single, solid but deformable shell which later began to fold and crack more widely, giving rise to modern plate tectonics, suggests new research.

The research is the latest salvo in a long-standing debate in the geological research community: Did plate tectonics start right away -- a theory known as uniformitarianism, or did the Earth first go through a long phase with a solid shell covering the entire planet? 

"Models for how the first continental crust formed generally fall into two groups: Those that invoke modern-style plate tectonics and those that do not," said study co-author Michael Brown, Professor at the University of Maryland in the US. 

"Our research supports the latter -- a 'stagnant lid' forming the planet's outer shell early in Earth's history," Brown said.

Today's Earth is a dynamic planet with an outer layer composed of giant plates that grind together, sliding past or dipping beneath one another, giving rise to earthquakes and volcanoes. 

Others separate at undersea mountain ridges, where molten rock spreads out from the centers of major ocean basins.

The new research, published in the journal Nature, suggests that plate tectonics began later in the Earth's history.

To reach these conclusions, Brown and his colleagues from Curtin University and the Geological Survey of Western Australia studied rocks collected from the East Pilbara Terrane, a large area of ancient granitic crust located in the state of Western Australia. 

The area is known for having some of the oldest known rocks, ranging from 3.5 to about 2.5 billion years of age. The Earth is roughly 4.5 billion years old.

The researchers specifically selected granites with a chemical composition usually associated with volcanic arcs -- a telltale sign of plate tectonic activity.

Based on their analysis, the researchers concluded that the Earth probably began with a solid outer shell.

"We conclude that a multi-stage process produced Earth's first continents in a 'stagnant lid' scenario before plate tectonics began," Brown said.