Notice: Undefined property: JObject::$description in /home/www/sreeharree.org/components/com_k2/templates/default/user.php on line 59
Scientists have for the first time discovered tiny magnetic particles from air pollution lodged in human brains - which could be a possible cause of Alzheimer's disease.
Researchers at Lancaster University in the UK found abundant magnetite nanoparticles in the brain tissue from 37 individuals aged three to 92-years-old who lived in Mexico City and Manchester.
This strongly magnetic mineral is toxic and has been implicated in the production of reactive oxygen species (free radicals) in the human brain, which are associated with neurodegenerative diseases including Alzheimer's disease.
Professor Barbara Maher, from Lancaster Environment Centre, used spectroscopic analysis to identify the particles as magnetite.
Unlike angular magnetite particles that are believed to form naturally within the brain, most of the observed particles were spherical, with diameters up to 150 nanometres (nm), some with fused surfaces, pointing to high-temperature formation - such as from vehicle engines or open fires.
The spherical particles are often accompanied by nanoparticles containing other metals, such as platinum, nickel, and cobalt.
"The particles we found are strikingly similar to the magnetite nanospheres that are abundant in the airborne pollution found in urban settings, especially next to busy roads, and which are formed by combustion or frictional heating from vehicle engines or brakes," said Maher.
Other sources of magnetite nanoparticles include open fires and poorly sealed stoves within homes.
Particles smaller than 200 nm are small enough to enter the brain directly through the olfactory nerve after breathing air pollution through the nose.
"Our results indicate that magnetite nanoparticles in the atmosphere can enter the human brain, where they might pose a risk to human health, including conditions such as Alzheimer's disease," said Maher.
"This finding opens up a whole new avenue for research into a possible environmental risk factor for a range of different brain diseases," said David Allsop, of Lancaster University's Faculty of Health and Medicine.The findings were published in the journal PNAS.
Courtesy – Deccan Herald
The reddish polar region on Pluto's largest moon, Charon, is an effect of methane gas escaping from the icy dwarf planet's atmosphere, say scientists who solved the mystery behind the coloured region first spotted by NASA's New Horizons spacecraft last year.
Methane gas escapes from Pluto's atmosphere, becomes "trapped" by the moon's gravity and freezes to the cold, icy surface at Charon's pole, researchers said.
This is followed by chemical processing by ultraviolet light from the Sun that transforms the methane into heavier hydrocarbons and eventually into reddish organic materials called tholins, they said.
"Who would have thought that Pluto is a graffiti artist, spray-painting its companion with a reddish stain that covers an area the size of New Mexico?" said Will Grundy, a New Horizons co-investigator from Lowell Observatory in the US.
"Nature is amazingly inventive in using the basic laws of physics and chemistry to create spectacular landscapes," Grundy said.
The team combined analyses from detailed Charon images obtained by New Horizons with computer models of how ice evolves on Charon's poles.
Mission scientists had previously speculated that methane from Pluto's atmosphere was trapped in Charon's north pole and slowly converted into the reddish material, but had no models to support that theory.
Researchers dug into the data to determine whether conditions on the moon (with a diameter of 1,212 kilometres) could allow the capture and processing of methane gas.
The models using Pluto and Charon's 248-year orbit around the Sun show some extreme weather at Charon's poles, where 100 years of continuous sunlight alternate with another century of continuous darkness.
Surface temperatures during these long winters dip to minus 257 degrees Celsius, cold enough to freeze methane gas into a solid.
"The methane molecules bounce around on Charon's surface until they either escape back into space or land on the cold pole, where they freeze solid, forming a thin coating of methane ice that lasts until sunlight comes back in the spring," Grundy said.
But while the methane ice quickly sublimates away, the heavier hydrocarbons created from it remain on the surface.
The models also suggested that in Charon's springtime the returning sunlight triggers conversion of the frozen methane back into gas.
However, while the methane ice quickly sublimates away, the heavier hydrocarbons created from this evaporative process remain on the surface.
Sunlight further irradiates those leftovers into reddish material - called tholins - that has slowly accumulated on Charon's poles over millions of years.
New Horizons' observations of Charon's other pole, currently in winter darkness - and seen by New Horizons only by light reflecting from Pluto, or "Pluto-shine" - confirmed that the same activity was occurring at both poles.
Courtesy – Deccan Herald
Pregnant women may be up to 1.5 times more likely to develop gestational diabetes during the summer months, a new study has found.
Seasonality in the onset of type-1 diabetes is well documented, with some studies showing higher winter incidence associated with higher circulating virus levels and lower vitamin D status.
However, less is known about the seasonality in the diagnosis of type-2 and gestational diabetes (GDM).
Researchers at Lund University and Skane University Hospital in Sweden examined seasonal patterns in glucose tolerance and in the diagnosis of GDM.
A total of 11,538 women who had agreed to take part underwent a universally applied standard 75-gramme oral glucose tolerance test (OGTT) in the 28th week of pregnancy during 2003-2005 in southern Sweden.
OGTT results from a three-year study period were grouped together into months and seasons.
Statistical modelling was used to calculate differences in GDM across months and seasons, and to examine whether month or season were associated with the diagnosis of GDM.
Information on mean monthly temperatures during the study period was obtained from the Swedish Meteorological and Hydrological Institute.
A total of 487 women (4.2 per cent) were diagnosed with GDM during the study period. The monthly frequency of GDM ranged from 2.9 per cent in March to 5.8 per cent in June.
The seasonal frequency ranged from 3.3 per cent in spring to 5.5 per cent in summer. The differences were statistically significant for both month and season.
Mean monthly temperature ranged from minus 0.6 degrees Celsius in the winter to 17.7 degrees Celsius in the summer.
When adjusted for age, the data showed that the summer months (June-August) were associated with an increased glucose level and a 51 per cent (or 1.5 times) increased frequency of GDM compared with the other seasons.
These associations were no longer apparent when also adjusting for mean monthly temperature, suggesting that temperature could be part of the reason for the differences.
"Our findings suggest seasonal variations in the glucose concentration and in the proportion of women diagnosed with GDM with a peak in the summer. A positive association with the ambient temperature was demonstrated," researchers said.
They add that a potential mechanism for this relationship is that hypothetically, temperature-induced changes in peripheral blood flow may affect the composition of capillary blood, representing a mixture of arterial and venous blood, explaining the increased glucose levels during the warmer summer months.
Courtesy – Deccan Herald
Hard, oxygen-poor tumours trigger a biological switch that causes cancer stem cells to invade other tissues, and could offer a promising treatment target to stop the disease from spreading, scientists have found.
Scientists from Princeton University and the Mayo Clinic Cancer Centre in the US suggests that the biological switch is critical to a tumour's ability to invade other tissue, a process called metastasis.
"Our study suggests that to combat cancer, we should be developing treatments that target the stiff, hypoxic regions of tumours," said lead author Celeste Nelson, professor at Princeton.
"We were surprised to see just how important these two properties in the tumour microenvironment - stiffness and hypoxia - were for regulating cancer stem cells," Nelson said.
The specific cells triggered by stiffness and hypoxia are called cancer stem cells. These cells represent only a small proportion of the total cells in a tumour, but researchers believe they play a key role in spreading the disease.
As normal stem cells help form an embryo, or aid in repairing muscles, cancer stem cells specialise in generating new malignant cells.
In addition to spreading cancer, just 10 to 100 leftover cancer stem cells are needed to regenerate a tumour after it has been removed.
Using cultures of human breast-cancer cells and mouse mammary-cancer cells, researchers discovered an association between a protein called integrin-linked kinase and the creation of cancer stem cells.
Normally, integrin-linked kinase assists cells with a variety of important cellular tasks. But in dense, oxygen-poor tumours, the protein's function goes awry.
Researchers created a range of human and mouse breast-cancer cultures reflecting different tissue conditions.
They showed that stiff hypoxic cultures did indeed promote cancer stem cells.
However, when they eliminated the integrin-linked kinase from those samples, they found that the cancer stem cells stopped forming.
Conversely, when they forced abnormal levels of integrin-linked kinase in samples containing softer or less hypoxic tissue, cancer stem cells formed.
They also confirmed a significant association between tumour stiffness, integrin-linked kinase and cancer stem cell presence in samples from human breast-cancer patients.
The findings suggest that stiffness and hypoxia cause integrin-linked kinase to behave abnormally, which in turn triggers cancer stem-cell formation.
There are likely other features in tumours that cause cancer stem cells to form, but the findings indicate that stiff, hypoxic conditions and their effects on integrin-linked kinase are two of the most prominent ones.The study appears in the journal Cancer Research
Courtesy – Deccan Herald
Neuroscientists have identified two key regions in our brain which merge fleeting views of our surroundings into a seamless, 360-degree panorama.
"Our understanding of our environment is largely shaped by our memory for what's currently out of sight," said Caroline Robertson, a postdoc at Massachusetts Institute of Technology (MIT) in the US.
"What we were looking for are hubs in the brain where your memories for the panoramic environment are integrated with your current field of view," said Robertson.
As we look at a scene, visual information flows from our retinas into the brain, which has regions that are responsible for processing different elements of what we see, such as faces or objects.
The team suspected that areas involved in processing scenes - the occipital place area (OPA), the retrosplenial complex (RSC), and parahippocampal place area (PPA) - might also be involved in generating panoramic memories of a place such as a street corner.
If this were true, when you saw two images of houses that you knew were across the street from each other, they would evoke similar patterns of activity in these specialised brain regions. Two houses from different streets would not induce similar patterns.
"Our hypothesis was that as we begin to build memory of the environment around us, there would be certain regions of the brain where the representation of a single image would start to overlap with representations of other views from the same scene," Robertson said.
The researchers explored this hypothesis using immersive virtual reality headsets, which allowed them to show people many different panoramic scenes.
In this study, the researchers showed participants images from 40 street corners in Boston's Beacon Hill neighborhood.
The images were presented in two ways: Half the time, participants saw a 100-degree stretch of a 360-degree scene, but the other half of the time, they saw two noncontinuous stretches of a 360-degree scene.
After showing participants these panoramic environments, the researchers then showed them 40 pairs of images and asked if they came from the same street corner.
Participants were much better able to determine if pairs came from the same corner if they had seen the two scenes linked in the 100-degree image than if they had seen them unlinked.
Brain scans showed that when participants saw two images that they knew were linked, the response patterns in the RSC and OPA regions were similar.
However, this was not the case for image pairs that the participants had not seen as linked. This suggests that the RSC and OPA, but not the PPA, are involved in building panoramic memories of our surroundings, researchers said.
The study appears in the journal Current Biology.
Courtesy – Deccan Herald
The US space agency launched its first mission to collect dust from an asteroid, the kind of cosmic body that may have delivered life-giving materials to Earth billions of years ago.
The unmanned spacecraft, known as OSIRIS-REx, blasted off at 7:05 pm (local time) atop an Atlas V rocket in Cape Canaveral, Florida.
The USD 800 million mission will travel for two years on a journey to Bennu, a near-Earth asteroid about the size of a small mountain.
Bennu was chosen from the some 500,000 asteroids in the solar system because it orbits close to Earth's path around the sun, it is the right size for scientific study, and it is one of the oldest asteroids known to NASA.
"For primitive, carbon-rich asteroids like Bennu, materials are preserved from over four and a half billion years ago," explained Christina Richey, OSIRIS-REx deputy program scientist at NASA.
These "may be the precursors to life in Earth or elsewhere in our solar system." OSIRIS-REx's main goal is to gather dirt and debris from the surface of the asteroid and return it to Earth by 2023 for further study.
Learning more about the origins of life and the beginning of the solar system are key objectives for the SUV-sized OSIRIS-REx, which stands for Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer.
The mission should also shed light on how to find precious resources such as water and metals in asteroids, a field that has generated increasing interest worldwide.
"We are going to map this brand-new world that we have never seen before," said Dante Lauretta, OSIRIS-REx principal investigator and professor at the University of Arizona, Tucson.
Using a suite of cameras, lasers and spectrometers, "we are really going to understand the distribution of materials across the surface of that asteroid," he added.
"We are a trailblazer for that kind of activity because our science requires it." The spacecraft is expected to reach Bennu in August 2018 and spend two years studying it before it begins the sample collection attempt in July 2020.
NASA hopes the solar-powered OSIRIS-REx will bring back the largest payload of space samples since the Apollo era of the 1960s and 1970s, when American explorers collected and carried back to Earth some 800 pounds (360 kilogrammes) of moon rocks.
The collection device, known as the Touch-and-Go Sample Acquisition Mechanism (TAGSAM), should pick up about two ounces (60 grams) from the asteroid, but in tests so far it has generally picked up five times that amount.
TAGSAM contains a type of reverse-vacuum mechanism that was invented by a Lockheed Martin engineer who tested the concept a decade ago using a red plastic Solo cup in his driveway.
Courtesy – Deccan Herald
The release of methane from the seafloor was much slower than previously thought during a rapid global warming event 56 million years ago that caused the extinction of many species, a new study has found.
The study led by researchers at the University of Southampton in the UK could allow scientists to better understand the potential effects of rising ocean temperatures worldwide on current and future climate change.
Around 56 million years ago, during the Paleocene-Eocene Thermal Maximum (PETM), temperatures in the deep ocean rose by about five degrees Celsius and sea surface temperatures increased by up to nine degrees Celsius.
The PETM period lasted for about 100,000 years and caused the extinction of many species.
Based on evidence from tiny fossils deposited in sediments at the bottom of the ocean, which record information about the chemical composition of the ocean in their shells, current theories suggest that at the same time as the warming there was a massive release of methane gas from the solid earth into the ocean and atmosphere.
A large proportion of the Earth's methane is stored beneath the oceans in the form of an ice-like material called hydrate.
This hydrate can melt if the ocean above warms, and melting of hydrate provides a widely accepted mechanism for the methane outburst.
However, the research from the University of Southampton and the National Oceanography Centre casts doubt on this mechanism.
Using computer models of the warming process, the researchers simulated the effects of PETM ocean warming on sediments that may have contained methane hydrate and tracked how methane transport mechanisms would have affected its release into seawater.
"Our results show that hydrate melting can indeed be triggered by ocean temperature change, but the result is not necessarily a rapid outburst of methane," said lead author of the study, Tim Minshull, Professor at Southampton.
"This is because the methane gas formed by hydrate melting below the sea floor takes time to travel up to the seabed, and on the way it can refreeze or dissolve and then be consumed by microbes that live below the seabed," Minshull said.
"Only a fraction of the methane may escape into the ocean and the part that does escape may take thousands of years to do so," he said.
"To explain the geological observations by melting of hydrate, much more hydrate must have been present globally than is perhaps reasonable for such a warm late Palaeocene Ocean," said Professor Paul Wilson from Southampton.
"And special transport routes would have been needed - perhaps cracks and fissures - to allow the methane to rise to the seabed quickly," he added.
The study appears in the journal Geophysical Research Letters.
Courtesy – Deccan Herald
In a step towards extending the lifespan of pet dogs, scientists have found that a drug used in humans with kidney transplants significantly improved the heart health of canines.
The anti-rejection medicine rapamycin, which is given to patients who have undergone kidney transplants, has been shown to extend the life of mice by more than 25 per cent.
If found to have a similar impact in canines, it could help dogs live for an extra four years, researchers said.
Scientists at the University of Washington in the US, have been conducting phase 1 trials to see if rapamycin could ward off death.
Some dogs have been known to survive until they are 29, and in the wild they live longer than household pets, so scientists are confident that animals have it in them to stay healthy for longer than they do presently.
"There were statistically significant improvements in heart function in the dogs that received rapamycin relative to those that received the placebo," Dr Matt Kaeberlein, professor at University of Washington.
The first trials have been conducted on 24 middle-aged golden retrievers, Labradors and German shepherd dogs to see if the adding low doses of rapamycin to their food could improve health and slow down ageing, 'The Telegraph' reported.
The initial phase was intended to simply show that the drug was safe to be administered, without side effects. However, scientists have seen heart improvements.
"The key findings are that there were no significant side effects associated with the rapamycin treatment, and there were statistically significant improvements in heart function in the dogs that received rapamycin relative to those that received the placebo, similar to what has been observed in older laboratory mice," said Kaeberlein.
Courtesy – Deccan Herald
Climate change is making the life of the soldiers posted in the world's highest and arduous battlefield - Siachen Glacier - not just tough but also dangerous, as temperature rises and the snow melts faster.
Siachen, which has the dubious distinction of having seen more soldiers dying due to extreme weather (temperatures at times drop below -50 degree celcius) than the enemy bullet, is feeling the heat of global warming.
The death of 10 soldiers earlier this year in an avalanche in the critical Sonam post, located close to the Line of Control with Pakistan, was due to global warming.
"The entire incident (at Sonam) was because of climate change only. Because, we generally don't have ice avalanches. Avalanches are generally snow avalanches.
"What happened in Sonam was that a hanging glacier, which was stuck to the ice wall had fallen off. That was just because in the last 15 or 20 days (prior to the accident), the temperature had been rising," Lt Col S Sengupta, Commandant of the Siachen Battle School told PTI.
Lance Naik Hanumanthappa, who was rescued after being buried 30 feet below snow for six days at the Sonam Post, located at about 19,600 feet, could not be saved.
Sengupta said that climate change actually makes the glacier break, due to which a lot of crevasses, one of the deadliest enemies of the soldier in Siachen, keep coming up.
"It (rising temperature) is making life tough," he said. The Army has now taken some precautionary measures and even moved some of the posts a little.
Keeping ice avalanches in mind, the Army is buying special radars that can detect humans buried under ice, unlike the earlier ones which could detect only through the snow.
The Army is also equipping its men with Avalanche Buoyance Systems - air bags that can be triggered remotely - which prevent burial in an avalanche by providing extra buoyancy.
The effect of the climate change is such that the snout of the Siachen Glacier has actually receded back by about 800 metres in the last one decade or so.
Over 41 soldiers have lost their lives on the Siachen Glacier since 2013, even though not a single shot has been fired since the ceasefire between India and Pakistan in 2003.
At least 1,013 Indian soldiers have lost their lives in Siachen since 1984.
The studies carried out by ISRO, Wadia Institute of Himalayan Geology (WIGH) Dehradun and other institutions have revealed that majority of the glaciers in India are retreating (melting) at varying rates from 5-20 metre per year.
The situation is such that at this time of the year, more than the pristine white snow, what you find more is black snow (often called moraine).
The river Nubra, which flows through the Base Camp, is actually black in colour rather than blue it was once.
"Global warming is definitely having its side effects on the glacier but things are different during summers. During the winters, the pristine white snow will be back and the waters will again become blue," a senior officer said.
Explaining the impact of climate change in Siachen, officers said that over a decade ago, rains were never seen here. However, the area now witnesses light drizzle in between over the past few years.
"Earlier one could not see any greenery over 12,000 feet. Now one can even see some green at even 15,000 feet which shows how temperatures have risen over the years," another officer said.
Courtesy – Deccan Herald
Not just the Sun, but the light travelling from galaxies across the universe for billions of years is also responsible for our suntans, scientists say.
We are constantly bombarded by about 10 billion photons per second from intergalactic space when we are outside, day and night, a new study has found.
When we lie on the beach, our bodies are bombarded by about sextillion photons of light per second, researchers said.
Most of these photons, or small packets of energy, originate from the Sun but a very small fraction have travelled across the universe for billions of years before ending their existence when they collide with your skin, they said.
Astronomers accurately measured the light hitting Earth from outside our galaxy over a very broad wavelength range.
The research looked at photons whose wavelengths vary from a fraction of a micron (damaging) to millimetres (harmless).
However, radiation from outside the galaxy constitutes only ten trillionths of your suntan, so there is no immediate need for alarm, researchers said.
"Most of the photons of light hitting us originate from the Sun, whether directly, scattered by the sky, or reflected off dust in the Solar System," said Simon Driver, Professor at the International Centre for Radio Astronomy Research (ICRAR), who led the study.
"However, we're also bathed in radiation from beyond our galaxy, called the extra-galactic background light," Driver said.
"These photons are minted in the cores of stars in distant galaxies, and from matter as it spirals into supermassive black holes," he added.
Driver, who is based at the University of Western Australia, measured this ambient radiation from the Universe, from a wide range of wavelengths by combining deep images from a flotilla of space telescopes.
While 10 billion photons a second might sound like a lot, Professor Driver said we would have to bask in it for trillions of years before it caused any long-lasting damage.
Rogier Windhorst, from Arizona State University, said the Universe also comes with its own inbuilt protection as about half the energy coming from the ultraviolet light of galaxies is converted into a less damaging wavelength by dust grains.
"The galaxies themselves provide us with a natural suntan lotion with an SPF of about two," he said. The study was published in the Astrophysical Journal.
Courtesy – Deccan Herald