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Comment by Dr. Krishna Kumari Challa on August 12, 2016 at 9:42am

For the first time scientists can see where molecular tags known as epigenetic marks are placed in the brain.

These chemical tags — which flag DNA or its protein associates, known as histones —don’t change the genes, but can change gene activity. Abnormal epigenetic marks have been associated with brain disorders such as Alzheimer’s disease, schizophrenia, depression and addiction.

Researchers at Massachusetts General Hospital in Boston devised a tracer molecule that latches onto a protein that makes one type of epigenetic mark, known as histone acetylation.

The scientists then used PET scans to detect where a radioactive version of the tracer marked the brains of eight healthy young adult men and women, the researchers report August 10 in Science Translational Medicine. Further studies could show that the marks change as people grow older or develop a disease. The team studied only healthy young volunteers so can’t yet say whether epigenetic marking changes with age or disease.

Comment by Dr. Krishna Kumari Challa on August 10, 2016 at 8:39am

The mighty monsoon winds that periodically bring rains that drench India first billowed around 12.9 million years ago, new research shows. The work provides the best look yet at the conditions that fostered the modern monsoon.

By examining sediments piled up around Indian Ocean islands, researchers uncovered a geologic history of the South Asian monsoon stretching back tens of millions of years. The monsoon winds began abruptly, researchers report online July 20 in Scientific Reports. That speedy start-up suggests that factors such as global cooling were at play in addition to the rise of the Himalayan mountain range, which scientists typically blame for the monsoon’s inception.

Rainfall during the summer monsoon season accounts for more than 70 percent of India’s annual precipitation. The temperature difference between the continent and the adjacent Indian Ocean drives the winds. During winter, warm air over the ocean rises and draws in cool air from the land to the north. In summer, the land becomes warmer and the winds flip direction.

The snow and high elevation of the Himalayas drive the temperature difference between the land and sea. But the mountains grew over tens of millions of years, making it difficult to determine exactly when conditions favorable to the monsoon began. Previous estimates ranged from around 28.7 million to 7 million years ago.

Monsoon winds drive currents in the ocean, which in turn carry ocean sediments across the sea. Sediment accumulates in mounds similar to snowdrifts when currents are strong. The strong currents also pull nutrients from the seafloor toward the surface, boosting biological activity that in turn draws oxygen from the water. That lower oxygen supply leaves a chemical trace in the sediments.

The researchers drilled around 500 meters into the seafloor and extracted sediments dating back roughly 25 million years. A weaker precursor to the modern monsoon existed roughly 25 million years ago, the sediment data suggest. Around 12.9 million years ago, however, the winds revved up to their modern strength over the course of about 300,000 years, a relatively short time compared with the formation of the Himalayas.

The strengthening of the monsoon lines up with a period of global cooling and the growth of the polar ice caps. That climate shift may have boosted the temperature difference between the land and sea, supercharging the winds, the researchers propose.

http://www.nature.com/articles/srep29838

Comment by Dr. Krishna Kumari Challa on August 7, 2016 at 1:27pm

The stimulation hypothesis

Comment by Dr. Krishna Kumari Challa on August 6, 2016 at 5:13am

Carbon Nanotubes: Ultrabreathable and Protective Membranes with Sub-5 nm Carbon Nanotube Pores 

to protect soldiers from biological and chemical threats, a team of Lawrence Livermore National Laboratory scientists has created a material that is highly breathable yet protective from biological agents.

This material is the first key component of futuristic smart uniforms that also will respond to and protect from environmental chemical hazards. The research appears in the July 27 edition of the journal,Advanced Materials 

The LLNL team fabricated flexible polymeric membranes with aligned carbon nanotube (CNT) channels as moisture conductive pores. The size of these pores (less than 5 nanometers, nm) is 5,000 times smaller than the width of a human hair.

To provide high breathability, the new composite material takes advantage of the unique transport properties of carbon nanotube pores. By quantifying the membrane permeability to water vapor, the team found for the first time that, when a concentration gradient is used as a driving force, CNT nanochannels can sustain gas-transport rates exceeding that of a well-known diffusion theory by more than one order of magnitude.

These membranes also provide protection from biological agents due to their very small pore size — less than 5 nanometers (nm) wide. Biological threats like bacteria or viruses are much larger and typically more than 10-nm in size. 

http://onlinelibrary.wiley.com/doi/10.1002/adma.201670197/full

Comment by Dr. Krishna Kumari Challa on August 5, 2016 at 9:13am

Transfer of mitochondria from astrocytes to neurons after stroke

Under duress, nerve cells get a little help from their friends. Brain cells called astrocytes send their own energy-producing mitochondria to struggling nerve cells. Those gifts may help the neurons rebound after injuries such as strokes, scientists propose in the July 28 Nature.

It was known that astrocytes — star-shaped glial cells that, among other jobs, support neurons — take in and dispose of neurons’ discarded mitochondria. Now it turns out that mitochondria can move the other way, too. This astrocyte-to-neuron transfer is surprising.
Mitochondria produce the energy that powers cells in the body. Scientists have spotted the organelles moving into damaged cells in other parts of the body, including the lungs, heart and liver. The new study turns up signs of this mitochondrial generosity in the brain.

Not only do the mitochondria make it into neurons, they actually help. Neurons with donated mitochondria better survived their starvation diet. When grown in dishes without extra mitochondria floating around, neurons were less able to weather the poor conditions, the researchers found.

Further experiments suggest that the transfer happens not just in lab dishes, but in the brains of mice. A day after mice received a strokelike injury, astrocyte-produced mitochondria showed up inside their neurons. The gift giving seems to depend on a protein called CD38, which sits on the outside of astrocytes and may detect distress signals. When CD38 wasn’t functioning, the mice had fewer mitochondria in their neurons. What’s more, the mice were worse at balancing on wires than mice with normal CD38 behavior, a deficit that may be linked to having too few mitochondria in neurons.

The results bolster the idea that mitochondria donations between cells may have tremendous therapeutic potential

http://www.nature.com/nature/journal/v535/n7613/full/nature18928.html

Comment by Dr. Krishna Kumari Challa on August 5, 2016 at 9:00am

Neonicotinoid insecticides become inadvertent insect contraceptives!

Over the last year, beekeepers in some parts of the world  lost nearly half of their honeybee hives. And there are a lot of suspected culprits for this so-called beepocalypse—from parasitic mites, to viruses, to simple land use changes. But a recent study pointed to another possibility: poor sperm quality among the drone bees, leading to colony crashes. And now another group of researchers may have found a reason for the subpar sperm: neonicotinoid pesticides. These substances contain chemicals similar to nicotine and affect insect nervous systems. 

"So for the drones that were exposed to pesticides during development, it appears there were more dead sperm in their reproductive tracts." 

Williams and his colleagues studied the effects of two neonicotinoid pesticides on honeybee drones, genetically assigned to mate with queens. 

But in 20 honeybee hives Williams and his collaborators found that those drones exposed to standard environmental levels of the pesticides were shorter-lived, thus having fewer opportunities to mate. And even if the drones did survive, they had nearly 40 percent fewer living sperm than did control bees—meaning the pesticides were acting like honeybee contraceptives. 

http://rspb.royalsocietypublishing.org/content/283/1835/20160506

Comment by Dr. Krishna Kumari Challa on August 5, 2016 at 8:32am

Io’s Atmosphere Collapses
Jupiter's shadow makes this volcanic moon's atmosphere freeze solid once per day
Jupiter's active moon Io has a collapsible atmosphere: New views show the satellite's shroud of sulfur dioxide freezing when Io enters its planet's shadow each day and converting back to gas when the moon emerges.
Io, Jupiter's fifth moon, is the solar system's most volcanically active body; plumes of the sulfur dioxide gas bursts from multiple active volcanoes, reaching up to 300 miles (480 kilometers) above the moon's surface at a scalding 3,000 degrees Fahrenheit (1,650 degrees Celsius). The Jupiter moon's surface, on the other hand, is frigidly cold, and gets even colder when Jupiter blocks out the sun—which prompts the atmospheric collapse.

Io's atmosphere is in a constant state of collapse and repair, and shows that a large fraction of the atmosphere is supported by sublimation of sulfur dioxide ice

Comment by Dr. Krishna Kumari Challa on August 3, 2016 at 9:27am

What factors affect contact lens discomfort? Optometry and Vision Science presents research update.

up to 50 percent of contact lens wearers experience dryness or discomfort at least occasionally. New research aimed at understanding and managing this common and complex problem is presented in the special August issue of Optometry and Vision Science, official journal of the American Academy of Optometry. The journal is published by Wolters Kluwer.

http://www.eurekalert.org/pub_releases/2016-08/wkh-wfa080116.php

Comment by Dr. Krishna Kumari Challa on August 2, 2016 at 7:46am

Comment by Dr. Krishna Kumari Challa on July 30, 2016 at 5:04am

Graphene-based sheets make dirty water drinkable simply and cheaply!
Engineers at the Washington University in St. Louis (WUSTL) have developed graphene-based biofoam sheets that can be laid on dirty or salty dams and ponds to produce clean drinking water, using the power of the sun. This new technique could be a cheap and simple way to help provide fresh water in countries where large areas of water are contaminated with suspended particles of dirt and other floating matter.

The biofilm is created as a two-layered structure consisting of two nanocellulose layers produced by bacteria. The lower layer contains pristine cellulose, while the top layer also contains graphene oxide, which absorbs sunlight and produces heat. The system works by drawing up water from underneath like a sponge where it then evaporates in the topmost layer, leaving behind any suspended particulates or salts. Fresh water then condenses on the top, where it can be drawn off and used.

The results of this research were recently published in the journal Advanced Materials.

Source: Washington University in St.Louis

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