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Comment by Dr. Krishna Kumari Challa on April 24, 2016 at 8:49am

Comment by Dr. Krishna Kumari Challa on April 23, 2016 at 7:14am

Ice-nucleating bacteria control the order and dynamics of interfacial water
Scientists recently have uncovered how tiny bacteria — nature’s ice machines — create ice crystals. Though the new study, published today in the journal Science Advances, doesn’t confirm whether these are rain-making bacteria, it points to how exactly they turn water into ice.

The bacteria, Pseudomonas syringae, have equipped themselves to cause the cold with proteins that create ice crystals at temperatures that don't normally freeze water. P. syringae live on agricultural crops, plants, and trees and use their ice-making abilities to cause frost damage. The ice crystals they produce basically shatter plants’ tissues so the bacteria can access the plants’ nutrients. We’ve even harnessed these organisms for our own purposes: P. syringae are routinely used to make artificial snow in ski resorts around the world.
In past decades, P. syringae have been found in the atmosphere, as well as in (real) snow from all over the world, from the US to Europe and even Antarctica. This study now study is the first one to show in an experiment how the ice-making mechanism actually works.
Pure water doesn’t freeze at 32 degrees Fahrenheit (0 degrees Celsius). It actually stays liquid until about - 40 degrees Fahrenheit (- 40 degrees Celsius). To freeze at higher temperatures, water needs a fleck of dust, soot, or sea salt — something to serve as a center that water molecules can latch onto. Most scientists believe that P. syringae are swept by wind from the ground to the sky. In the atmosphere, these high-flying, ice-making bacteria lower the freezing temperature to around 25 to 18 degrees Fahrenheit (- 4 to - 8 degrees Celsius) and form ice crystals. That creates clouds, which are basically agglomerations of water droplets and ice crystals.
To make rain, your clouds have to form first an ice crystal, even in the Sahara desert. As the ice crystals fall down, they turn into rain if it’s warm and snow if it’s cold. The theory that bacteria like P. syringae have a role in causing precipitation, however, has never been proved. "Intuitively it feels right, circumstantial evidence says yes, but that final link has not been done yet.
http://advances.sciencemag.org/content/2/4/e1501630

Comment by Dr. Krishna Kumari Challa on April 21, 2016 at 9:22am

Explosive cell lysis as a mechanism for the biogenesis of bacterial membrane vesicles and biofilms
A recent study by an international team of researchers has identified a phenomenon called explosive cell lysis as crucial to the production of membrane vesicles and biofilm formation, two processes that are key to how bacteria form and attack healthy cells. The study was published in Nature Communications. Membrane vesicles are tiny spheres that develop from bacterial membranes and contain a mixture of proteins, DNA, and RNA. They are important to bacteria’s ability to cause disease as they play vital roles in invasion, secretion, and signaling. They also contribute to the formation of biofilms, the slimy three-dimensional structures that form when bacteria adhere to moist surfaces such as teeth or wounds. Extracellular DNA (eDNA) is key to the structural organization of biofilms, yet it was not previously known how certain structural proteins or eDNA are released. To answer this question, the researchers used live cell microscopy of the pathogenic bacterium Pseudomonas aeruginosa to reveal that bacterial cells quickly changed from rod- to round-shaped, and then explode.
Using super-resolution microscopy to follow the explosions, they found a surprising observation. The membrane fragments produced by exploding bacteria curled up to form membrane vesicles that captured eDNA and other cellular components released by the explosion.
The team found that the explosions are caused by an enzyme (Lys) used by bacteria-infecting viruses (phages) and phage-like elements to disrupt the cell wall of their hosts. Using a mutant bacterial strain incapable of producing Lys, they discovered that the enzyme was needed to produce eDNA and membrane vesicles. Through a range of experiments, the team also demonstrated that exposure of cells to different forms of stress, such as antibiotics or DNA damaging agents, stimulated expression of the gene encoding Lys and induced explosive cell lysis. This shows that the bacterial ‘SOS’ response triggers explosive cell lysis in response to unfavorable environmental conditions, according to the researchers. This mechanism may enable bacteria to release important cellular factors for use by bacterial communities as public goods, and knowledge of its control could be used to interfere with biofilm formation of pathogenic bacteria.
http://www.nature.com/ncomms/2016/160414/ncomms11220/full/ncomms112...

Comment by Dr. Krishna Kumari Challa on April 21, 2016 at 8:44am

In a study published this week in Proceedings of the National Academy of Sciences, a pair of researchers at the INSERM–CEA Cognitive Neuroimaging Unit in France reported that the brain areas involved in math are different from those engaged in equally complex nonmathematical thinking.
The team used functional magnetic resonance imaging (fMRI) to scan the brains of 15 professional mathematicians and 15 nonmathematicians of the same academic standing. While in the scanner the subjects listened to a series of 72 high-level mathematical statements, divided evenly among algebra, analysis, geometry and topology, as well as 18 high-level nonmathematical (mostly historical) statements. They had four seconds to reflect on each proposition and determine whether it was true, false or meaningless.
The researchers found that in the mathematicians only, listening to math-related statements activated a network involving bilateral intraparietal, dorsal prefrontal, and inferior temporal regions of the brain. This circuitry is usually not associated with areas involved in language processing and semantics, which were activated in both mathematicians and nonmathematicians when they were presented with the nonmathematical statements. “On the contrary,” says study co-author and graduate student Marie Amalric, “our results show that high-level mathematical reflection recycles brain regions associated with an evolutionarily ancient knowledge of number and space.”
How Does a Mathematician's Brain Differ from That of a Mere Mortal?
Processing high-level math concepts uses the same neural networks as the basic math skills a child is born with

Comment by Dr. Krishna Kumari Challa on April 19, 2016 at 6:41am

These trained African Giant Pouched Rats can detect TB in a short span of time! It takes about nine months to fully train a TB detection rat, but once trained they can screen thousands of sputum samples every month. The idea was spurred by the superb sense of smell of these rats which had been used to detect land mines after the Mozambican civil war.

The rats pick up in their smell a group of chemicals collectively called volatile organic compounds (VOCs) and the rats alert an observer that there are TB-associated VOCs in a sample.

The same principle has been used to develop machines called electronic noses.

Comment by Dr. Krishna Kumari Challa on April 18, 2016 at 7:07am

Why can anyone easily shot down a helicopter?
The reason they are so prone to being shot down according to experts is two fold... they rely on the tail rotor (or boom in the case of a NOTAR design) to produce the anti-torque to counter act the torque that needs to be applied to the main rotor. Take out that tail rotor and you can no longer power or even generate lift at all from the main rotor without spinning out of control (due to induced drag of the rotor blades). This is of course not applicable to co-axial helicopters which use two main rotor blades counter spinning to counteract torque. A shrouded tail rotor is less likely to strike objects and suffer catastrophic failure but is still susceptible to bullets and other projectiles hitting it. A NOTAR design using the Coanda effect has an extremely resilient anti torque mechanism but gives up maneuverability.

Secondly, the main rotor hub is an extremely complex piece of machinery. It must control collective pitch, cyclical pitch, spin extremely fast ( typically around 5 - 10 revs per second) which causing huge forces pulling it apart and essentially hold the weight plus maneuvering load of the helicopter. A great number of things can go wrong.

Losing power to the main rotor means certain death, but it is actually fairly easy to recover from and helicopter pilots actually practice it pretty regularly. They perform what's called an autorotation in which they immediately (upon sensing engine failure) lower the collective pitch to maintain rotor momentum, which will cause the helicopter to start to descent. They then push the nose forward to gain a forward momentum and start picking out a place to land (or crash depending on the rest of how the scenario plays out). The forward momentum allows the rotor to continue generating lift and the rotational momentum of the rotor will be used as a last second flare to slow descent and hopefully land smoothly. The most dangerous thing for a helicopter to do is to hover (no horizontal movement) at a low height above ground because there will be little that can be done to recover from a loss of power to the main rotor.

Also - 

1. They can't fly that fast, or at least not as fast as airplanes. This makes it easier to engage them with all kinds of AA weapons, even including small weapon fire.
2. They have to fly low, especially when they are supposed to give ground support, unload troop, or extract them from the battlefield. Once again, this makes them vulnerable to all kinds of weapons.
3. They have to be stationary during critical moments, such as unloading and loading personnel, or once again proving air support (sometimes). Not only are they easier to shoot at, but they also have less "energy" to perform evasive maneuvers, or get out of there.

To summarise it all together, helicopters have less "energy" when they are being shot at, in the sense that they are lower in altitude, and usually slower, if not standing perfectly still. This makes them vulnerable to small weapons fire, and basically does not allow the pilot to perform any kind of evasive maneuver.

Comment by Dr. Krishna Kumari Challa on April 16, 2016 at 10:02am

A new particle?!

Comment by Dr. Krishna Kumari Challa on April 15, 2016 at 7:27am

The sugar, cyclodextrin, removed cholesterol that had built up in the arteries of mice fed a high-fat diet, researchers report April 6 in Science Translational Medicine. The sugar enhances a natural cholesterol-removal process and persuades immune cells to soothe inflammation instead of provoking it, say immunologist Eicke Latz and colleagues.

Cyclodextrin, more formally known as 2-hydroxypropyl-beta-cyclodextrin, is the active ingredient in the air freshener Febreze. It is also used in a wide variety of drugs; it helps make hormones, antifungal chemicals, steroids and other compounds soluble. If the new results hold up in human studies, the sugar may also one day be used to liquefy cholesterol that clogs arteries.

Other researchers say the approach is promising, but must be tested in clinical trials. The sweet molecule is generally considered safe, but injecting it may raise the risk of liver damage or hearing loss.
http://stm.sciencemag.org/content/8/333/333ra50

Comment by Dr. Krishna Kumari Challa on April 13, 2016 at 6:38am

Plan to Send Probes to the Nearest Star
Funded by Russian entrepreneur Yuri Milner and with the blessing of Stephen Hawking, Breakthrough Starshot aims to send probes to Alpha Centauri in a generation
For Yuri Milner, the Russian Internet entrepreneur and billionaire philanthropist who funds the world’s richest science prizes and searches for extraterrestrial intelligence, the sky is not the limit—and neither is the solar system. Flanked by physicist Stephen Hawking and other high-profile supporters today in New York, Milner announced his most ambitious investment yet: $100 million toward a research program to send robotic probes to nearby stars within a generation.
- Scientific American

Comment by Dr. Krishna Kumari Challa on April 9, 2016 at 8:19am

Scientists blast comet-like ice with radiation like that in space, creating RNA - a key building block for life!
Scientists have produced the first formation of a key sugar required for life as we know it. By creating ices similar to those detected by the European Space Agency's Rosetta mission, which made the first landing on a comet, scientists were able to produce ribose, a sugar that serves as an important ingredient in RNA, an essential ingredient for life.
Cornelia Meinert, an associate scientist at the University Nice Sophia Antipolis led experiments that dosed icy materials produced in a laboratory with radiation similar to what comets would have received in the early life of the solar system, resulting in the creation of ribose.
Meinert and her colleagues recreated ices detected by Rosetta's Philae lander when it touched down on Comet 67P in 2014. In a lab, they created interstellar ices under what Meinert called "realistic astrophysical conditions" — in other words, within a vacuum, surrounded by low temperatures. Then, they blasted the samples with radiation simulating energy from the young sun, which was far more active than today's star, along with cosmic rays from the rest of the galaxy. Some of the material from the ices evaporated, while the leftover material created an organic residue. Sampling this residue revealed not only sugars but also amino acids, alcohols and other material.

The research was published online today (April 7) in the journal Science. - 
Source: http://www.space.com

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