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Comment by Dr. Krishna Kumari Challa on December 6, 2013 at 10:01am

How mosquitoes are drawn to human skin and breath
Part 1
Female mosquitoes, which can transmit deadly diseases like malaria, dengue fever, West Nile virus and filariasis, are attracted to us by smelling the carbon dioxide we exhale, being capable of tracking us down even from a distance. But once they get close to us, they often steer away toward exposed areas such as ankles and feet, being drawn there by skin odors. Why does the mosquito change its track and fly towards skin? How does it detect our skin? What are the odors from skin that it detects? And can we block the mosquito skin odor sensors and reduce attractiveness?

Recent research done by scientists at the University of California, Riverside can now help address these questions. They report on Dec. 5 in the journal Cell that the very receptors in the mosquito's maxillary palp that detect carbon dioxide are ones that detect skin odors as well, thus explaining why mosquitoes are attracted to skin odor -- smelly socks, worn clothes, bedding -- even in the absence of CO2.
"It was a real surprise when we found that the mosquito's CO2 receptor neuron, designated cpA, is an extremely sensitive detector of several skin odorants as well, and is, in fact, far more sensitive to some of these odor molecules as compared to CO2," said Anandasankar Ray, an associate professor in the Department of Entomology and the project's principal investigator. "For many years we had primarily focused on the complex antennae of mosquitoes for our search for human-skin odor receptors, and ignored the simpler maxillary palp organs."
Until now, which mosquito olfactory neurons were required for attraction to skin odor remained a mystery. The new finding -- that the CO2-sensitive olfactory neuron is also a sensitive detector of human skin -- is critical not only for understanding the basis of the mosquito's host attraction and host preference, but also because it identifies this dual receptor of CO2 and skin-odorants as a key target that could be useful to disrupt host-seeking behavior and thus aid in the control of disease transmission.
To test whether cpA activation by human odor is important for attraction, the researchers devised a novel chemical-based strategy to shut down the activity of cpA in Aedes aegypti, the dengue-spreading mosquito. They then tested the mosquito's behavior on human foot odor -- specifically, on a dish of foot odor-laden beads placed in an experimental wind tunnel -- and found the mosquito's attraction to the odor was greatly reduced.
Next, using a chemical computational method they developed, the researchers screened nearly half a million compounds and identified thousands of predicted ligands. They then short-listed 138 compounds based on desirable characteristics such as smell, safety, cost and whether these occurred naturally. Several compounds either inhibited or activated cpA neurons of which nearly 85 percent were already approved for use as flavor, fragrance or cosmetic agents. Better still, several were pleasant-smelling, such as minty, raspberry, chocolate, etc., increasing their value for practical use in mosquito control.
The researchers then zeroed in on two compounds: ethyl pyruvate, a fruity-scented cpA inhibitor approved as a flavor agent in food; and cyclopentanone, a minty-smelling cpA activator approved as a flavor and fragrance agent. By inhibiting the cpA neuron, ethyl pyruvate was found in their experiments to substantially reduce the mosquito's attraction towards a human arm. By activating the cpA neuron, cyclopentanone served as a powerful lure, like CO2, attracting mosquitoes to a trap.
http://esciencenews.com/articles/2013/12/05/how.mosquitoes.are.draw...

Comment by Dr. Krishna Kumari Challa on December 6, 2013 at 9:57am

Study shows how water dissolves stone, molecule by molecule
http://esciencenews.com/articles/2013/12/05/study.shows.how.water.d...

Comment by Dr. Krishna Kumari Challa on December 6, 2013 at 7:09am

The Replication Myth: Shedding Light on One of Science’s Dirty Little Secrets
http://blogs.scientificamerican.com/guest-blog/2013/12/04/the-repli...

Comment by Dr. Krishna Kumari Challa on December 4, 2013 at 9:44am

Just Thinking About Light Or Dark Can Change Your Pupil Size!
Animals involuntarily constrict or dilate their pupils if they are sensing either too much or not enough light entering the eye, respectively. Now, a new study from a pair of Norwegian researchers has found that simply imagining a scene that is either too brightly or dimly lit can affect the size of your pupils.

“Visual imagery is a private and subjective experience which is not accompanied by strongly felt or visible physiological changes,” explained study author Bruno Laeng, a psychological scientist from the University of Oslo. “It is a particularly difficult topic to research, as years of controversy about the nature of mental imagery testifies.”

Along with his University of Oslo colleague Unni Sulutvedt, Laeng performed a series of experiments to determine if they could access subjective mental imagery by tracking the size of pupils. The Norwegian team started by having participants look at a display while triangles of different degrees of brightness were shown. Later, participants were asked to actively imagine those triangles.

The researchers wrote in their report in the journal Psychological Science that participants’ pupils would vary in size according to an original triangle’s brightness. For example, when imagining brighter triangles, participants’ pupils were smaller and when imagining darker triangles, participants’ pupils were dilated.

In another series of experiments, participants’ pupils also dilated or constricted when they were told to picture a dark room or a face in the sun compared with a face in the shade. Additional experiments demonstrated that the results were not due to voluntary changes in pupil size or the mental effort spent imagining scenes, the researchers said.

“Because humans cannot voluntarily constrict the eyes’ pupils, the presence of pupillary adjustments to imaginary light presents a strong case for mental imagery as a process based on brain states similar to those which arise during actual perception,” Laeng said.

The research team suggested that their findings could be applied to future studies involving the mental experiences of animals, babies, and even patients with neurological problems.

http://www.redorbit.com/news/health/1113018564/mental-imagery-affec...

Comment by Dr. Krishna Kumari Challa on December 4, 2013 at 9:42am

Study shows energy drinks 'significantly increased' heart contractions

A new study has showed that energy drinks can affect the heart beats of even healthy adults hours after consumption.
Test subjects were monitored using an MRI scanner after drinking the heavily caffeinated beverages, with researchers from the University of Bonn reporting the drinks “significantly increased” heart contraction rates.

"Until now, we haven't known exactly what effect these energy drinks have on the function of the heart," said Dr. Jonas Dörner, one of the study’s authors. “There are concerns about the products' potential adverse side effects on heart function, especially in adolescents and young adults, but there is little or no regulation of energy drink sales.”

"Usually energy drinks contain taurine and caffeine as their main pharmacological ingredients. The amount of caffeine is up to three times higher than in other caffeinated beverages like coffee or cola.”

Dörner also noted that the side-effects of consuming large amounts of caffeine could include “a rapid heart rate, palpitations, rise in blood pressure and, in the most severe cases, seizures or sudden death”.

http://www.independent.co.uk/news/science/study-shows-energy-drinks...

Comment by Dr. Krishna Kumari Challa on December 4, 2013 at 9:40am

Men And Women’s Brains Are ‘Strikingly’ Complimentary
Men and women have ‘striking’ differences in their neural wiring that might explain some of the behavioral differences between the two sexes, according to a study published Monday in the Proceedings of National Academy of Sciences.

The study was one of the largest to date to create to compare the connectomes, neural maps of the brain, of men and women.

The results revealed that men have far greater neural connectivity from front to back and within one brain hemisphere, suggesting their brains are structured to facilitate connectivity between perception and coordinated action. However, in females, this wiring goes between the left and right brain hemispheres, suggesting that women facilitate communication between the analytic and intuitive parts of the brain, the researchers said.

“These maps show us a stark difference – and complementarity – in the architecture of the human brain that helps provide a potential neural basis as to why men excel at certain tasks, and women at others,” said study leader Ragini Verma, PhD, an associate professor in the department of Radiology at the Perelman School of Medicine at the University of Pennsylvania.

For instance, on average, men are more likely better at learning and performing a single task at hand, like cycling or navigating directions, whereas women have superior memory and social cognition skills, making them better equipped for multitasking and creating solutions that work for a group. In other words, they have what’s called a mentalistic approach.

The human brain is a complex roadmap of neural pathways linking many networks that help us process information and react accordingly, with behavior controlled by several of these sub-networks working in conjunction.

Although previous research has revealed gender differences in the brain, the current study is the first to show the neural wiring connecting regions across the whole brain among a large population.

http://www.redorbit.com/news/science/1113017910/male-and-female-bra...

Comment by Dr. Krishna Kumari Challa on December 4, 2013 at 9:26am

'Science' named other word of the year for 2013 by Merriam-Webster

While Oxford University Press, the British publisher of the Oxford dictionaries, declared those little smartphone self-portraits its winner last month, the folks at Merriam-Webster announced "science" on Tuesday.

Oxford tracked a huge jump in overall usage of selfie, but Merriam-Webster stuck primarily to lookups on its website, recording a 176 per cent increase for science when compared to last year.

"The more we thought about it, the righter it seemed in that it does lurk behind a lot of big stories that we as a society are grappling with, whether it's climate change or environmental regulation or what's in our textbooks," said John Morse, president and publisher of Merriam-Webster Inc, based in Springfield, Massachusetts.

Science, he said, is connected to broad cultural oppositions - science versus faith, for instance - along with the power of observation and intuition, reason and ideology, evidence and tradition. Of particular note, to Merriam-Webster, anyway, is fallout from the October release of Malcolm Gladwell's latest book, David and Goliath: Underdogs, Misfits, and the Art of Battling Giants.

http://www.heraldsun.com.au/technology/science/science-named-other-...

Comment by Dr. Krishna Kumari Challa on December 3, 2013 at 8:42am

7 important science Stories
http://www.asianscientist.com/topnews/7-must-read-stories-november-...

Comment by Dr. Krishna Kumari Challa on December 3, 2013 at 8:34am

Sorting Good Bacteria From Bad
Arizona State University scientists have developed a microfluidic chip, which can sort good germs from bad.
Your intestines are home to about 100 trillion bacteria. That’s more than the number of cells that comprise the entire human body. Armies of bacteria sneak into our bodies the moment we are born, uninvited but necessary guests.
For the most part, these bacteria are industrious and friendly. Some of them are even beneficial, helping with digestion and producing vitamins. A few miscreants, though, will kill us if we let them stay.
Sometimes the difference between harmless and harmful is miniscule. Take E. coli for instance. Billions of E. coli organisms live in the average person’s intestines. They go about their business causing no trouble whatsoever. However, one particular strain of E. coli, O157:H7, causes about 2,000 hospitalizations and 60 deaths in the U.S. every year. The differences between this strain and others are detectable only at the molecular level. But how do we separate friend from foe? Determining whether or not bacteria are harmful usually requires growing cultures from food or infected patients. This is a time-consuming process that must be carried out in a laboratory. We stand to gain much from new technologies that can rapidly identify microorganisms.
Scientists at Arizona State University’s Department of Chemistry and Biochemistry, have developed a new device that could significantly speed up the identification process for harmful bacteria and other microorganisms. The team is led by Professor Mark A.
Identification takes place within a microscopically small channel in a chip made from glass or silicone polymer. The microchannel features saw-tooth shapes that allow researchers to sort and concentrate microbes based on their unique electrical properties.
The phenomenon that makes this work is called dielectrophoresis, which involves an applied voltage that exerts force upon the bacteria.
This force acts like a coin-sorter, causing bacteria to become trapped at different points along the channel. Where they stop, and at what voltage, depends on their molecular and electrical properties.
Using this approach, Hayes’s team has separated extremely similar bacteria—pathogenic and nonpathogenic strains within the single species, E. coli. O157:H7 is very similar in size and shape to other subtypes of the bacteria. But unlike many of the others it has the ability to produce shiga-like toxin, a protein that breaks down blood vessel walls in the digestive tract.”
Fortunately, all of these bacterial strains also possess subtle, but telltale differences in the proteins and other molecules that they express on their surface. According to Professor Hayes, dielectrophoresis is well suited to probe these phenotypic differences.
The researchers used an ordinary strain of E. coli along with two pathogenic varieties. They injected the cells into each channel and simply applied voltage to drive the cells downstream. The geometric features of the channel shape the electric field, creating regions of different intensity. This field creates the dielectrophoretic force that allows some cells to pass, while trapping others based on their phenotype.

So far, the device has only been used to test pure cultures of bacteria, but they hope soon to test complex mixtures of particles that are found in nature or the human body.

The next step is to create cheap, portable devices that would enable point-of-care or field based analysis. Such a device would require no time-consuming culturing or other tests, which would allow rapid response to disease or contamination, hopefully saving lives.
On The Net: Arizona State University
http://www.redorbit.com/news/science/1113017062/sorting-good-bacter...

Comment by Dr. Krishna Kumari Challa on December 2, 2013 at 9:37am

http://www.independent.co.uk/news/science/the-smell-of-fear-can-be-...
There is increasing evidence from a number of studies that what we inherit from out parents is very complex and that the gametes – the sperm and eggs – may be a possible mechanism of conserving as much information as possible from a previous generation,” said Kerry Ressler, professor of psychiatry at Emory School of Medicine in Atlanta, Georgia.

“The biggest interpretation of this research, if it holds up across mammals, is that it may be possible for certain traits such as the fearful experience of a parent to be transmitted to subsequent generations
The findings also lend some support to a discredited theory known as the "inheritance of acquired characteristics", promulgated by Jean-Baptiste Lamarck in the late 18th Century. Lamarck postulated that organisms can pass on physical features they developed during their lifetime to their offspring, such as the long neck of giraffes which stretched to reach the highest leaves on a tree.

Butt this idea was later supplanted by Charles Darwin's theory of natural selection, which was further supported by the discovery of genes and Mendelian inheritance. The latest study, however, shows that a kind of Lamarckism may in fact exist in nature as a result of environmental influences directly affecting epigenetic changes to an organism's DNA.
"The smell of fear can be inherited, scientists prove"

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