Comment

Comment by Dr. Krishna Kumari Challa on November 24, 2016 at 8:44am

Must read ... An open letter from women of science

 Women scientists' pledge...

https://500womenscientists.org/#our-pledge

Comment by Dr. Krishna Kumari Challa on November 24, 2016 at 8:05am

How what you eat effects your gut...

Mucus plays a major role in your gut. There are antimicrobial peptides and proteins that are present in the environment. Bacteria live in your gut and forage on the carbohydrates. And it's a lubricant, it helps sweep contents down the GI tract, without injuring the epithelial layer. In the colon, the mucus builds a wall: a barrier against friendly bacteria, as well as pathogens that could be transiting through. But here's the problem: your gut bacteria may chew right through that wall—if you skimp on fiber in your diet. 

In the studies conducted on mice, extreme high-fiber diet helped keep the mucus barrier intact. But in mice that had zero fiber—or the kind of soluble fiber typically added to processed foods—the fiber-eating members of the gut dwindled. Their absence opened up more space for mucus-munching bacteria, which increased in number, and tore through the protective mucus wall—leaving intestinal cells open for microbial attack. The study's published in the journal Cell. 

Your diet could predispose how you react to an enteric pathogen. Eating natural vegetables, raw vegetables, cooked veggies, whole grains, is definitely good for you. Interestingly, the mice's gut bacteria bounced back within a day to a change in diet. 

A Dietary Fiber-Deprived Gut Microbiota Degrades the Colonic Mucus Barrier and Enhances Pathogen Susceptibility

http://www.cell.com/cell/abstract/S0092-8674(16)31464-7

Comment by Dr. Krishna Kumari Challa on November 18, 2016 at 8:43am

Scientists have hacked a plant's genes to make it use sunlight more efficiently — a breakthrough that could eventually dramatically increase the amount of food grown.

Photosynthesis is how plants convert sunlight, carbon dioxide and water into food. But it's a very inefficient process, using less than 1 percent of the energy available.

By genetically modifying part of the plant's protective system, which kicks into gear when too much sunlight beams down, scientists were able to increase leaf growth between 14 and 20 percent in experiments with tobacco plants, according to a study published on 18th Nov., 2016 in the journal Science .

http://science.sciencemag.org/content/354/6314/857

Comment by Dr. Krishna Kumari Challa on November 18, 2016 at 8:31am

Popular heartburn drugs —  under investigation for possible links to dementia, kidney and heart problems — have a new health concern to add to the list. An analysis of almost 250,000 medical records in Denmark has found an association with stroke.

Researchers from the Danish Heart Foundation in Copenhagen studied patients undergoing gastric endoscopy from 1997 to 2012. About 9,500 of all patients studied suffered from ischemic strokes, which occur when a blood clot blocks a blood vessel in the brain.

Overall, the risk of stroke was 21 percent higher in patients taking a proton pump inhibitor, a drug that relieves heartburn, the researchers reported November 15 during the American Heart Association’s annual meeting. While those patients also tended to be older and sicker to start with, the level of risk was associated with dose, the researchers found. People taking the lowest drug doses (between 10 and 20 milligrams a day, depending on the drug) did not have a higher risk. At the highest doses, though, Prevacid (more than 60 mg/day) carried a 30 percent higher risk and Protonix (more than 80 mg/day) a 94 percent higher risk. For Prilosec and Nexium, stroke risk fell within that range.  

T.S. Sehested et al. Proton pump inhibitor use increases the associated risk of first-ti.... American Heart Association Scientific Sessions, New Orleans, November 15, 2016.

M. Rosen. Heartburn drugs can damage cells that line blood vessels. Science News. Vol. 189, June 11, 2016, p. 8.

V. Savarino et al. The appropriate use of proton pump inhibitors (PPIs): Need for a re.... European Journal of Internal Medicine. Published online October 23, 2016. doi: 10.1016/j.ejim.2016.10.007. 

Comment by Dr. Krishna Kumari Challa on November 18, 2016 at 7:11am

Birds and other marine animals are eating the plastic we discard into the ocean as it breaks down into small pieces.Why? 

Two scientists from the University of California, Davis think they have the answer: the birds are drawn by the smell of a dimethyl sulfide released by plastic -- the same chemical released by phytoplankton.

Some birds (which the paper describes as “procellariiform species”) have a strong sense of smell, and respond to a certain chemical, dimethyl sulfide, as a cue to find their prey. And in a study released on 16th Nov., 2016 in Science Advances, their suspicions were confirmed.

Dimethyl sulfide is released by phytoplankton as it gets eaten by a predator or breaks down in the ocean or on shore, signaling to these birds and others to come eat the phytoplankton’s predators (like krill).

Dr. Nevitt and Mr. Savoca found that the chemical is also released when tiny pieces of plastic are present in the ocean, often a result of “biofouling,” which describes the process when algae colonizes pieces of plastic, and then die or are eaten by other organisms.

In this study, the scientists used plastic beads of the type used in bottles, bags, textiles and hundreds of applications, ranging from four to six millimeters in diameter. After the microplastics had been in the ocean for about three weeks, dimethyl sulfide was found in the water and air around them in concentrations high enough that these types of birds may be able to smell, the scientists found, using tools that are otherwise meant for measuring sulfur in beer or wine.

The study suggests that the odor of dimethyl sulfide on or around marine plastic debris is “maladaptive foraging behavior” — that the birds are using their evolutionary traits to forage for food in ways that might be bad for them, causing problems like chemical toxicity or obstruction. According to the study, a recent projection model concluded that more than 99 percent of all seabird species will have eaten plastic debris by 2050.

Dr. Nevitt said that the study could have implications for other marine animals. Those that eat similar species to these birds — like baleen whales — or those that may also be attracted to dimethyl sulfide — like sea turtles — could be at risk. The researchers hope the study will help determine strategies for how to fight this growing environmental problem, as plastic pollution increases in the ocean.

http://advances.sciencemag.org/content/2/11/e1600395

Comment by Dr. Krishna Kumari Challa on November 11, 2016 at 7:40am

Why Neanderthal DNA wasn't much successful...

Neanderthals and modern humans got separated  from a common ancestor about half a million years ago.

Living in colder climes in Eurasia, Neanderthals evolved barrel chests, large skulls and strong hands. In Africa, modern humans acquired shorter faces, a prominent chin and slender limbs. Then, roughly 50,000 years ago, the two species encountered one another and interbred, as modern humans spread out of Africa.

The legacy of this interbreeding has been the subject of much scientific inquiry in the past few years. Today, up to 4 percent of the genes of non-Africans are Neanderthal in origin.. These may have influenced a diverse range of traits, including keratin production, disease risk. Where did all the other Neanderthal DNA go? Why did a Neanderthal-human hybrid not prevail?

Two recent studies converge on an explanation. They suggest the answer comes down to different population sizes between Neanderthals and modern humans, and this principle of population genetics: In small populations, natural selection is less effective.

Neanderthals have this small population over hundreds of thousands of years, presumably because they’re living in very rough conditions. As a result, Neanderthals were more inbred than modern humans and accumulated more mutations that have a slightly adverse effect, such as increasing one’s risk of disease, but do not prevent one from reproducing .

After Neanderthals started mating with humans, natural selection in the larger human population started excluding.

http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pg...

Comment by Dr. Krishna Kumari Challa on November 10, 2016 at 6:22am

New type of atomic bond

Scientists have for the first time observed a weak atomic bond – in which an electron can grab and trap an atom – that was theorised 14 years ago. Researchers at Purdue University in the US observed a butterfly Rydberg molecule, a weak pairing of two highly excitable atoms that they predicted would exist more than a decade ago.

Rydberg molecules are formed when an electron is kicked far from an atom’s nucleus. Chris Greene, Professor of Physics and Astronomy at Purdue, and colleagues theorised in 2002 that such a molecule could attract and bind to another atom.

For all normal atoms, the electrons are always just one or two angstroms away from the nucleus, but in these Rydberg atoms you can get them 100 or 1,000 times farther away. Following preliminary work in the late 1980s and early 1990s, we saw in 2002 the possibility that this distant
Rydberg electron could bind the atom to another atom at a very large distance.

This electron is like a sheepdog. Every time it whizzes past another atom, this Rydberg atom adds a little attraction and nudges it towards one spot until it captures and binds the two atoms together.

A collaboration involving Greene and his postdoctoral associate Jesus Perez-Rios at Purdue and researchers at the University of Kaiserslautern in Germany has now proven the existence of the butterfly Rydberg molecule, so named for the shape of its electron cloud.  This new binding mechanism, in which an electron can grab and trap an atom, is really new from the point of view of chemistry. It’s a whole new way an atom can be bound by another atom.

The researchers cooled Rubidium gas to a temperature of 100 nano-Kelvin, about one ten-millionth of a degree above absolute zero. Using a laser, they were able to push an electron from its nucleus, creating a Rydberg atom, and then watch it.

Whenever another atom happens to be at about the right distance, you can adjust the laser frequency to capture that group of atoms that are at a very clear internuclear separation that is predicted by our theoretical treatment.

They were able to detect the energy of binding between the two atoms based on changes in the frequency of light that the Rydberg molecule absorbed.

The findings were published in the journal Nature Communications.

http://www.nature.com/articles/ncomms12820

Comment by Dr. Krishna Kumari Challa on November 9, 2016 at 7:28am

Supersolids: strange state of matter

Two teams of scientists report the creation of supersolids, which are both liquid and solid at the same time. Supersolids have a crystalline structure like a solid, but can simultaneously flow like a superfluid, a liquid that flows without friction.

Research teams from MIT and ETH Zurich both produced supersolids in an exotic form of matter known as a Bose-Einstein condensate. Reports of the work were published online at arXiv.org on October 26 (by the MIT group) and September 28 (by the Zurich group).

Bose-Einstein condensates are created when a group of atoms, chilled to near absolute zero, huddle up into the same quantum state and begin behaving like a single entity. The scientists’ trick for creating a supersolid was to nudge the condensate, which is already a superfluid, into simultaneously behaving like a solid. To do so, the MIT and Zurich teams created regular density variations in the atoms — like the repeating crystal structure of a more typical solid — in the system. That density variation stays put, even though the fluid can still flow.

The two groups of scientists formed their supersolids in different ways. By zapping their condensate with lasers, the MIT group induced an interaction that gave some of the atoms a shove. This motion caused an interference between the pushed and the motionless atoms that’s similar to the complex patterns of ripples that can occur when waves of water meet. As a result, zebralike stripes — alternating high- and low-density regions — formed in the material,  indicating that it was a solid.

Applying a different method, the ETH Zurich team used two optical cavities — sets of mirrors between which light bounces back and forth repeatedly. The light waves inside the cavities caused atoms to interact and thereby arrange themselves into a crystalline pattern, with atoms separated by an integer number of wavelengths of light.

J. Li et al. Observation of the supersolid stripe phase in spin-orbit coupled Bo.... arXiv:1610.08194. Posted October 26, 2016.

J. Léonard et al. Supersolid formation in a quantum gas breaking continuous translati.... arXiv:1609.09053. Posted September 28, 2016.

Comment by Dr. Krishna Kumari Challa on November 5, 2016 at 7:09am

Transient Weakening of Earth’s Magnetic Shield Probed by a Cosmic Ray Burst

The GRAPES-3 muon telescope located at TIFR's Cosmic Ray Laboratory in Ooty recorded a burst of galactic cosmic rays of about 20 GeV, on 22 June 2015 lasting for two hours.

The burst occurred when a giant cloud of plasma ejected from the solar corona, and moving with a speed of about 2.5 million kilometers per hour struck our planet, causing a severe compression of Earth's magnetosphere from 11 to 4 times the radius of Earth. It triggered a severe geomagnetic storm that generated aurora borealis, and radio signal blackouts in many high latitude countries.

Earth's magnetosphere extends over a radius of a million kilometers, which acts as the first line of defence, shielding us from the continuous flow of solar and galactic cosmic rays, thus protecting life on our planet from these high intensity energetic radiations. Numerical simulations performed by the GRAPES-3 collaboration on this event indicate that the Earth's magnetic shield temporarily cracked due to the occurrence of magnetic reconnection, allowing the lower energy galactic cosmic ray particles to enter our atmosphere. Earth's magnetic field bent these particles about 180 degree, from the day-side to the night-side of the Earth where it was detected as a burst by the GRAPES-3 muon telescope around mid-night on 22 June 2015. The data was analyzed and interpreted through extensive simulation over several weeks by using the 1280-core computing farm that was built in-house by the GRAPES-3 team of physicists and engineers at the Cosmic Ray Laboratory in Ooty.

Solar storms can cause major disruption to human civilization by crippling large electrical power grids, global positioning systems (GPS), satellite operations and communications.

The GRAPES-3 muon telescope, the largest and most sensitive cosmic ray monitor operating on Earth is playing a very significant role in the study of such events. 

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.171101

Comment by Dr. Krishna Kumari Challa on November 5, 2016 at 6:26am

An interesting  similarity between human cells and neutron stars

According to new research, we share at least one similarity with the neutron stars: the geometry of the matter that makes us. 

Researchers have found that the 'crust' (or outer layers) of a neutron star has the same shape as our cellular membranes. This could mean that, despite being fundamentally different, both humans and neutron stars are constrained by the same geometry.

To understand this finding, we need to quickly dive into the weird world of nuclear matter, which researchers call 'nuclear pasta' because it looks a lot like spaghetti and lasagne. 

This nuclear pasta forms in the dense crust of a neutron star thanks to long-range repulsive forces competing with something called the strong force, which is the force that binds quarks together.

In other words, two powerful forces are working against one another, forcing the matter – which consists of various particles – to structure itself in a scaffold-like (pasta) way.

"When you have a dense collection of protons and neutrons like you do on the surface of a neutron star, the strong nuclear force and the electromagnetic forces conspire to give you phases of matter you wouldn't be able to predict if you had just looked at those forces operating on small collections of neutrons and protons."

Now, it turns out that these pasta-like structures look a lot like the structures inside biological cells, even though they are vastly different.

This odd similarity was first discovered in 2014, when Huber was studying the unique shapes on our endoplasmic reticulum (ER) – the little organelle in our cells that makes proteins and lipids.

You can see the ER structures (left) compared to the neutron stars (right) below: 

University of California, Santa Barbara

The discovery brought both of the scientists together to compare and contrast the differences between the structures, such as the conditions required for them to form

Normally, matter is characterised by a phase – sometimes called its state – such as gas, solid, liquid Different phases are usually influenced by a plethora of various conditions, like how hot the matter is, how much pressure it’s under, and how dense it is.

These factors change wildly between soft matter (the stuff inside cells) and neutron stars (nuclear matter). After all, neutron stars form after supernovae explosions, and cells form within living things. With that in mind, it’s quite easy to see that the two things are very different.

For neutron stars, the strong nuclear force and the electromagnetic force create what is fundamentally a quantum mechanical problem.

"In the interior of cells, the forces that hold together membranes are fundamentally entropic and have to do with the minimisation of the overall free energy of the system. At first glance, these couldn't be more different."

The team’s work was published in Physical Review C.

• ‹ Previous
• 1
• …
• 872
• 873
• 874
• 875
• 876
• …
• 1081
• Next ›
• Page