Brighter Future for Solar Energy

The efficiency of conventional solar cells could be significantly increased, according to new research on the mechanisms of solar energy conversion led by chemist Xiaoyang Zhu at The University of Texas at Austin. Zhu and his team have discovered that it's possible to double the number of electrons harvested from one photon of sunlight using an organic plastic semiconductor material. "Plastic semiconductor solar cell production has great advantages, one of which is low cost," said Zhu, a professor of chemistry. "Combined with the vast capabilities for molecular design and synthesis, our discovery opens the door to an exciting new approach for solar energy conversion, leading to much higher efficiencies."  Zhu and his team published their groundbreaking discovery Dec. 16 inScience. The maximum theoretical efficiency of the silicon solar cell in use today is approximately 31 percent, because much of the sun's energy hitting the cell is too high to be turned into usable electricity. That energy, in the form of "hot electrons," is instead lost as heat. Capturing hot electrons could potentially increase the efficiency of solar-to-electric power conversion to as high as 66 percent.

Zhu and his team previously demonstrated that those hot electrons could be captured using semiconductor nanocrystals. They published that research in Science in 2010, but Zhu says the actual implementation of a viable technology based on that research is very challenging.

Why Almost All Multicellular Organisms Begin Life as a Single Cell

Any multicellular animal, from a blue whale to a human being, poses a special difficulty for the theory of evolution. Most of the cells in its body will die without reproducing, and only a privileged few will pass their genes to the next generation.How could the extreme degree of cooperation multicellular existence requires ever evolve? Why aren't all creatures unicellular individualists determined to pass on their own genes? Joan Strassmann, PhD, and David Queller, PhD, a husband and wife team of evolutionary biologists at Washington University in St. Louis, provide an answer in the Dec. 16 issue of the journal Science. Experiments with amoebae that usually live as individuals but must also join with others to form multicellular bodies to complete their life cycles showed that cooperation depends on kinship.

If amoebae occur in well-mixed cosmopolitan groups, then cheaters will always be able to thrive by freeloading on their cooperative neighbors. But if groups derive from a single cell, cheaters will usually occur in all-cheater groups and will have no cooperators to exploit.

The only exceptions are brand new cheater mutants in all-cooperator groups, and these could pose a problem if the mutation rate is high enough and there are many cells in the group to mutate. In fact, the scientists calculated just how many times amoebae that arose from a single cell can safely divide before cooperation degenerates into a free-for-all.

Ability to Love Takes Root in Earliest Infancy

The ability to trust, love, and resolve conflict with loved ones starts in childhood -- way earlier than you may think. That is one message of a new review of the literature inCurrent Directions in Psychological Science, a journal published by the Association for Psychological Science."Your interpersonal experiences with your mother during the first 12 to 18 months of life predict your behavior in romantic relationships 20 years later," says psychologist Jeffry A. Simpson, the author, with University of Minnesota colleagues W. Andrew Collins and Jessica E. Salvatore. "Before you can remember, before you have language to describe it, and in ways you aren't aware of, implicit attitudes get encoded into the mind," about how you'll be treated or how worthy you are of love and affection.

While those attitudes can change with new relationships, introspection, and therapy, in times of stress old patterns often reassert themselves. The mistreated infant becomes the defensive arguer; the baby whose mom was attentive and supportive works through problems, secure in the goodwill of the other person.

All It Takes Is a Smile

Does she or doesn't she . . .? Sexual cues are ambiguous, and confounding. We -- especially men -- often read them wrong. A new study hypothesizes that the men who get it wrong might be the ones that evolution has favored. "There are tons of studies showing that men think women are interested when they're not," says Williams College psychologist Carin Perilloux, who conducted the research with Judith A. Easton and David M. Buss of University of Texas at Austin. "Ours is the first to systematically examine individual differences." The findings will appear in an upcoming issue of Psychological Science, a journal published by the Association for Psychological Science.

The research involved 96 male 103 female undergraduates, who were put through a "speed-meeting" exercise -- talking for three minutes to each of five potential opposite-sex mates. Before the conversations, the participants rated themselves on their own attractiveness and were assessed for the level of their desire for a short-term sexual encounter. After each "meeting," they rated the partner on a number of measures, including physical attractiveness and sexual interest in the participant. The model had the advantage of testing the participants in multiple interactions.

The results: Men looking for a quick hookup were more likely to overestimate the women's desire for them. Men who thought they were hot also thought the women were hot for them -- but men who were actually attractive, by the women's ratings, did not make this mistake. The more attractive the woman was to the man, the more likely he was to overestimate her interest. And women tended to underestimate men's desire.

Botox Injected in Head ‘trigger Point’ Shown to Reduce Migraine Crises

Scientists at the University of Granada have confirmed that injecting a local anesthetic or botulinum toxin (botox) into certain points named "trigger points" of the pericraneal and neck muscles reduce migraine frequency among migraine sufferers. University of Granada researchers have identified the location of these trigger points -which activation results in migraine- and their relationship with the duration and severity of this condition. Headache is a universal experience. At present, there are more than 100 different types of headache and one of the most recurring ones is migraine, which affects approximately 10-12% of the population, being three times more common in women than in men. When migraine becomes chronic -occurring more than 15 days a month-, it can disrupt patients' daily life in a great degree.

This research study is one of the three studies that have been conducted by Juan Miguel García Leiva -a researcher at the University of Granada Institute for Neuroscience "Federico Oloriz" -- and coordinated by professor Elena Pita Calandre.

Why Hair Turns Gray

A new study by researchers at NYU Langone Medical Center has shown that, for the first time, Wnt signaling, already known to control many biological processes, between hair follicles and melanocyte stem cells can dictate hair pigmentation.The study was published in the June 11, 2011 issue of the journal Cell. The research was led by Mayumi Ito, PhD, assistant professor in the Ronald O. Pereleman Department of Dermatology at NYU Langone. "We have known for decades that hair follicle stem cells and pigment-producing melanocycte cells collaborate to produce colored hair, but the underlying reasons were unknown," said Dr. Ito. "We discovered Wnt signaling is essential for coordinated actions of these two stem cell lineages and critical for hair pigmentation." The study suggests the manipulation of Wnt signaling may be a novel strategy for targeting pigmentation such as graying hair. The research study also illustrates a model for tissue regeneration.

Eating Fish Reduces Risk of Alzheimer's Disease

People who eat baked or broiled fish on a weekly basis may be improving their brain health and reducing their risk of developing mild cognitive impairment (MCI) and Alzheimer's disease, according to a study presented November 30 at the annual meeting of the Radiological Society of North America (RSNA)."This is the first study to establish a direct relationship between fish consumption, brain structure and Alzheimer's risk," said Cyrus Raji, M.D., Ph.D., from the University of Pittsburgh Medical Center and the University of Pittsburgh School of Medicine. "The results showed that people who consumed baked or broiled fish at least one time per week had better preservation of gray matter volume on MRI in brain areas at risk for Alzheimer's disease."

Alzheimer's disease is an incurable, progressive brain disease that slowly destroys memory and cognitive skills. According to the National Institute on Aging, as many as 5.1 million Americans may have Alzheimer's disease. In MCI, memory loss is present but to a lesser extent than in Alzheimer's disease. People with MCI often go on to develop Alzheimer's disease.

Dreaming Takes the Sting out of Painful Memories

They say time heals all wounds, and new research from the University of California, Berkeley, indicates that time spent in dream sleep can help us overcome painful ordeals. UC Berkeley researchers have found that during the dream phase of sleep, also known as REM sleep, our stress chemistry shuts down and the brain processes emotional experiences and takes the edge off difficult memories. The findings offer a compelling explanation for why people with post-traumatic stress disorder (PTSD), such as war veterans, have a hard time recovering from distressing experiences and suffer reoccurring nightmares. They also offer clues into why we dream.

"The dream stage of sleep, based on its unique neurochemical composition, provides us with a form of overnight therapy, a soothing balm that removes the sharp edges from the prior day's emotional experiences," said Matthew Walker, associate professor of psychology and neuroscience at UC Berkeley and senior author of the study to be published on Nov. 23, in the journal Current Biology.

For people with PTSD, Walker said, this overnight therapy may not be working effectively, so when a "flashback is triggered by, say, a car backfiring, they relive the whole visceral experience once again because the emotion has not been properly stripped away from the memory during sleep."

First Planet in Habitable Zone Outside Our Solar System

NASA's Kepler mission has confirmed its first planet in the "habitable zone," the region around a star where liquid water could exist on a planet's surface. Kepler also has discovered more than 1,000 new planet candidates, nearly doubling its previously known count. Ten of these candidates are near-Earth-size and orbit in the habitable zone of their host star. Candidates require follow-up observations to verify they are actual planets. The newly confirmed planet, Kepler-22b, is the smallest yet found to orbit in the middle of the habitable zone of a star similar to our sun. The planet is about 2.4 times the radius of Earth. Scientists don't yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets.

Previous research hinted at the existence of near-Earth-size planets in habitable zones, but clear confirmation proved elusive. Two other small planets orbiting stars smaller and cooler than our sun recently were confirmed on the very edges of the habitable zone, with orbits more closely resembling those of Venus and Mars.

"This is a major milestone on the road to finding Earth's twin," said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington. "Kepler's results continue to demonstrate the importance of NASA's science missions, which aim to answer some of the biggest questions about our place in the universe."

More Weight Equals Longer Hospital Stays

Sociologists found a direct relationship between obesity and duration and frequency of hospital stays. Researchers found that, on average, obese persons stayed one and a half days longer than those with normal weight. Sociologists attribute the connection to disease--46 percent of obese adults have high blood pressure. Obesity is also linked to an increased risk of heart disease, diabetes, stroke and other illnesses. The researchers also note that the longer a person has been obese, the more likely their hospital stay is lengthened.

The numbers on our nation's scales are going up. A recent study puts Mississippi at the top of the list with the highest rate of adult obesity in the country. New research shows how extra weight is adding up to longer hospital stays.

Annette Armstead knows what it takes to stay healthy. Before she started exercising, she weighed 225 pounds.

"I was tired of people telling fat jokes," said Armstead. "I was in pain all the time. I was so heavy that my knees would give out on me, and I was always falling down."