Blood group may affect woman's fertility

Researchers from Yale University and the Albert Einstein College of Medicine in New York studied over 560 women with an average age of 35, all of whom were undergoing fertility treatment in two different clinics. Blood samples were taken from each of the women and analyzed for blood group and the levels of the follicle stimulating hormone (FSH).

FSH is a known marker of fertility, with lower levels (less than 10) suggesting a woman will have better chances of conceiving than one with higher levels. High levels of FSH indicate a diminished ovarian reserve, which means egg quality is poor and the quantity of eggs remaining may be low. The ovarian reserve declines naturally from the middle to late 30s.

The results of the study showed that among women seeking fertility treatment, those with blood group O had double the likelihood of having an FSH level over 10 than women with any other blood type. This result remained true when the results were adjusted to take into account the woman’s age and other factors such as body mass index (BMI), and was true for women from both clinics. Women with blood group A were significantly less likely to have FSH levels over 10.

Leader of the research team, Dr. Edward Nejat from the Albert Einstein College of Medicine’s department of obstetrics and gynecology, said women with blood type A and the much less common AB — both of which have the A blood group gene — were protected in some way from a diminished ovarian reserve. He said the study included "a good mix of patients ethnically and racially."

Dr. Nejat said baseline FSH levels "gives us an idea of the quality and quantity of a woman's eggs," but they were only one marker of fertility. He said more studies were needed to see if blood group affects other hormone levels, and to see if the same effects were seen in the general population and not just women who were already seeking treatment for fertility problems. Nejat added that the woman’s age remained the most important factor in fertility.

The results of the research will be presented in Denver at the annual conference of the American Society for Reproductive Medicine (ASRM). President of the ASRM, Dr. William Gibbons, said studies such as this were needed to help us to better understand the "complexities of the human reproductive system."

Scientists develop method for detecting microRNA from living cells

Probe-microRNA duplexes translocate through thin nanopores. (Artwork: Robert Johnson)

MicroRNAs, or miRNAs, were initially identified in roundworms in 1993. Since then, biologists have discovered that microRNAs control gene expression, and therefore there is immense interest in these molecules as potential therapeutics for silencing cancer and disease-related genes.

The problem with microRNA detection is that the number of copies of microRNA in cells is so small that detection is quite challenging. The team developed a method to fabricate nanopores in the thinnest silicon nitride membranes reported to date, about 6 nm thick.

First, the team showed that these nanopores increase the signal resolution from reading DNA molecules as they pass through the pores. After demonstrating the enhanced sensitivity, the Penn team needed a method to isolate a specific microRNA from cells.

They teamed with a group headed by Larry McReynolds of New England Biolabs.

“Larry and co-workers had a neat trick: they use a viral protein called p19 to tightly bind duplex RNA molecules of the exact dimensions of microRNAs,” Meni Wanunu, a research associate at Penn, said. “So we devised a plan that uses this protein to isolate very small amounts of specific microRNAs that we can then quantify using our pores.”

The team focused on detecting miR122a, a liver-specific microRNA in mammals.

They first demonstrated that their nanopores are reliable enough to quantify the concentrations of these tiny molecules that are only 22 bases long, or 6 nm in length. After having made ultrathin membranes by locally etching silicon nitride, the group used electron beams to drill the nanopores in the thinned portion of the silicon nitride membranes.

“Using 3 nm diameter pores, these duplex RNA molecules just squeeze through the pores and in doing so, each molecule produces a nice electronic signal,” Wanunu said. “We were delighted, things worked out really nice. These are the smallest synthetic pores in all dimensions, and it is surprising how stable and robust they are. We now use them routinely for various investigations; they are our new state-of-the-art.”

The article, featured on the cover of the November 2010 issue of Nature Nanotechnology, shows a duplex microRNA molecule passing through a very thin nanopore made at Penn.

“It is wonderful to see the expected improvements in signal to noise ratios using these thin nanopores,” Marija Drndić, an associate professor of physics and the group leader on the project, said. “In spite of their being thin, they are quite robust, and they seem to function every time because they do not tend to trap hydrophobic contaminants and they allow unimpeded flow through them. All this makes them ideal candidates for various biophysical applications.”

The Penn team is now working on specific methods for detecting other smallmolecules, as well as integrating these nanopores with fluidic systems to improve sensitivity.

The research was conducted by Wanunu, Drndić Tali Dadosh and Vishva Ray of Penn, and Jingmin Jin and McReynolds of New England Biolabs.

Brain Regions Can Switch Functions in Young

A new paper from MIT neuroscientists, in collaboration with Alvaro Pascual-Leone at Beth Israel Deaconess Medical Center, offers evidence that it is easier to rewire the brain early in life. The researchers found that a small part of the brain's visual cortex that processes motion became reorganized only in the brains of subjects who had been born blind, not those who became blind later in life.

Scientists offer evidence that it is easier to rewire the 
brain early in life. Researchers found that a small part 
of the brain's visual cortex that processes motion became
reorganized only in the brains of subjects who had been 
born blind, not those who became blind later in life.
(Credit: iStockphoto/Vasiliy Yakobchuk)

The new findings, described in the Oct. 14 issue of the journal Current Biology, shed light on how the brain wires itself during the first few years of life, and could help scientists understand how to optimize the brain's ability to be rewired later in life. That could become increasingly important as medical advances make it possible for congenitally blind people to have their sight restored, said MIT postdoctoral associate Marina Bedny, lead author of the paper.

In the 1950s and '60s, scientists began to think that certain brain functions develop normally only if an individual is exposed to relevant information, such as language or visual information, within a specific time period early in life. After that, they theorized, the brain loses the ability to change in response to new input.

Animal studies supported this theory. For example, cats blindfolded during the first months of life are unable to see normally after the blindfolds are removed. Similar periods of blindfolding in adulthood have no effect on vision.

However, there have been indications in recent years that there is more wiggle room than previously thought, said Bedny, who works in the laboratory of MIT assistant professor Rebecca Saxe, also an author of the Current Biology paper. Many neuroscientists now support the idea of a period early in life after which it is difficult, but not impossible, to rewire the brain.

Bedny, Saxe and their colleagues wanted to determine if a part of the brain known as the middle temporal complex (MT/MST) can be rewired at any time or only early in life. They chose to study MT/MST in part because it is one of the most studied visual areas. In sighted people, the MT region is specialized for motion vision.

In the few rare cases where patients have lost MT function in both hemispheres of the brain, they were unable to sense motion in a visual scene. For example, if someone poured water into a glass, they would see only a standing, frozen stream of water.

Previous studies have shown that in blind people, MT is taken over by sound processing, but those studies didn't distinguish between people who became blind early and late in life.

In the new MIT study, the researchers studied three groups of subjects -- sighted, congenitally blind, and those who became blind later in life (age nine or older). Using functional magnetic resonance imaging (fMRI), they tested whether MT in these subjects responded to moving sounds -- for example, approaching footsteps.

The results were clear, said Bedny. MT reacted to moving sounds in congenitally blind people, but not in sighted people or people who became blind at a later age.

This suggests that in late-blind individuals, the visual input they received in early years allowed the MT complex to develop its typical visual function, and it couldn't be remade to process sound after the person lost sight. Congenitally blind people never received any visual input, so the region was taken over by auditory input after birth.

"We need to think of early life as a window of opportunity to shape how the brain works," said Bedny. "That's not to say that later experience can't alter things, but it's easier to get organized early on."

Bedny believes that by better understanding how the brain is wired early in life, scientists may be able to learn how to rewire it later in life. There are now very few cases of sight restoration, but if it becomes more common, scientists will need to figure out how to retrain the patient's brain so it can process the new visual input.

"The unresolved question is whether the brain can relearn, and how that learning differs in an adult brain versus a child's brain," said Bedny.

Bedny hopes to study the behavioral consequences of the MT switch in future studies. Those would include whether blind people have an advantage over sighted people in auditory motion processing, and if they have a disadvantage if sight is restored.

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

Research Shows: Risk of Marijuana’s ‘gateway effect’ Overblown

     New research from the University of New Hampshire shows that the “gateway effect” of marijuana – that teenagers who use marijuana are more likely to move on to harder illicit drugs as young adults – is overblown.

Whether teenagers who smoked pot will use other illicit drugs as young adults has more to do with life factors such as employment status and stress, according to the new research. In fact, the strongest predictor of whether someone will use other illicit drugs is their race/ethnicity, not whether they ever used marijuana.

Conducted by UNH associate professors of sociology Karen Van Gundy and Cesar Rebellon, the research appears in the September 2010, issue of the Journal of Health and Social Behavior in the article, “A Life-course Perspective on the ‘Gateway Hypothesis.’ “

“In light of these findings, we urge U.S. drug control policymakers to consider stress and life-course approaches in their pursuit of solutions to the ‘drug problem,’ ” Van Gundy and Rebellon say.

The researchers used survey data from 1,286 young adults who attended Miami-Dade public schools in the 1990s. Within the final sample, 26 percent of the respondents are African American, 44 percent are Hispanic, and 30 percent are non-Hispanic white.

The researchers found that young adults who did not graduate from high school or attend college were more likely to have used marijuana as teenagers and other illicit substances in young adulthood. In addition, those who used marijuana as teenagers and were unemployed following high school were more likely to use other illicit drugs.

However, the association between teenage marijuana use and other illicit drug abuse by young adults fades once stresses, such as unemployment, diminish.

“Employment in young adulthood can protect people by ‘closing’ the marijuana gateway, so over-criminalizing youth marijuana use might create more serious problems if it interferes with later employment opportunities,” Van Gundy says.

In addition, once young adults reach age 21, the gateway effect subsides entirely.

“While marijuana use may serve as a gateway to other illicit drug use in adolescence, our results indicate that the effect may be short-lived, subsiding by age 21. Interestingly, age emerges as a protective status above and beyond the other life statuses and conditions considered here. We find that respondents ‘age out’ of marijuana’s gateway effect regardless of early teen stress exposure or education, work, or family statuses,” the researchers say.

The researchers found that the strongest predictor of other illicit drug use appears to be race-ethnicity, not prior use of marijuana. Non-Hispanic whites show the greatest odds of other illicit substance use, followed by Hispanics, and then by African Americans.

New Artificial “Skin” Can Sense Pressure

    New artificial “skin” fashioned out of flexible semiconductor materials can sense touch, making it possible to create robots with a grip delicate enough to hold an egg, yet strong enough to grasp the frying pan, U.S. researchers said on Sunday.

Scientists have long struggled with a way to make robotic devices capable of adjusting the amount of force needed to hold and use different objects. The pressure-sensitive materials are designed to overcome that challenge.

“Humans generally know how to hold a fragile egg without breaking it,” said Ali Javey, an electrical engineer at theUniversity of California Berkeley, who led one of two teams reporting on artificial skin discoveries in the journal Nature Materials.

“If we ever wanted a robot that could unload the dishes, for instance, we’d want to make sure it doesn’t break the wine glasses in the process. But we’d also want the robot to be able to grip a stock pot without dropping it,” Javey said in a statement.

Javey’s team found a way to make ultra tiny “nanowires” from an alloy of silicon and germanium. Wires of this material were formed on the outside of a cylindrical drum, which was then rolled onto a sticky film, depositing the wires in a uniform pattern.

Sheets of this semiconductor film were then coated with a layer of pressure-sensitive rubber. Tests of the material showed it was able to detect a range of force, from typing on a keyboard to holding an object.

A second team led by Zhenan Bao, a chemical engineer at Stanford University in California, used a different approach, making a material so sensitive it can detect the weight of a butterfly resting on it.

Bao’s sensors were made by sandwiching a precisely molded, highly elastic rubber layer between two electrodes in a regular grid of tiny pyramids.

“We molded it into some kind of microstructure to incorporate some air pockets,” Bao said in a telephone interview. “If we introduce air pockets, then these rubber pieces can bounce back.”

When this material is stretched, the artificial skin measures the change in electrical activity. “The change in the thickness of the material is converted into an electrical signal,” she said.

Eventually, the teams hope artificial skin could be used to restore the sense of touch in people with prosthetic limbs, but scientists will first need a better understanding of how to integrate the system’s sensors with the human nervous system.

Javey’s artificial skin is the latest application of new ways of processing brittle, inorganic semiconductor materials such as silicon, into flexible electronics and sensors.

Earlier this year, a team at the California Institute of Technology in Pasadena devised a way to make flexible solar cells with silicon wires that are thin enough to be used in clothing.

Printed Origami Offers New Technique for Complex Structues

Although it looks small and unassuming, the tiny origami crane sitting in a sample dish in University of Illinois professor Jennifer Lewis’ lab heralds a new method for creating complex three-dimensional structures for biocompatible devices, microscaffolding and other microsystems. The penny-sized titanium bird began as a printed sheet of titanium hydride ink.

    The team will publish their novel technique in the April 14 online edition of the journal Advanced Materials.

Small, intricate shapes made of metals, ceramics or polymers have a variety of applications, from biomedical devices to electronics to rapid prototyping. One method of fabricating such structures is by direct-write assembly, which the Lewis group helped pioneer. In this approach, a large printer deposits inks containing metallic, ceramic or plastic particles to assemble a structure layer by layer. Then, the structure is annealed at a high temperature to evaporate the liquid in the ink and bond the particles, leaving a solid object.

However, as more layers are added, the lower layers tend to sag or collapse under their own weight – a problem postdoctoral researcher Bok Yeop Ahn encountered while trying to manufacture titanium scaffolds for tissue engineering. He decided to try a different approach: Print a flat sheet, then roll it up into a spiral – or even fold it into an assortment of shapes.

Folding the printed sheets is not as easy as it would first seem.

    “Most of our inks are based on aqueous formulations, so they dry quickly. They become very stiff and can crack when folded,” said Lewis, the Thurnauer Professor of Materials Science and Engineering and the director of the university’s Frederick Seitz Materials Research Laboratory. The challenge, then, was to find a solution that would render the printed sheets pliable enough to manipulate yet firm enough to retain their shape after folding and during annealing.

    Lewis, Ahn and their research team solved the problem by mimicking wet-folding origami, in which paper is partially wetted to enhance its foldability. By using a mixture of fast-drying and slow-drying solvents in the ink, the sheet dries partway but stays flexible enough to fold through multiple steps – 15, in the case of the crane.

    The U. of I. researchers worked with professor David Dunand, the James and Margie Krebs Professor of Materials Science at Northwestern University, who initially approached Lewis with the possibility of titanium hydride inks. “I knew how to transform hydride into metallic titanium without contamination from the ink, based on prior research in my lab,” said Dunand, who focused on annealing the soft, titanium hydride origami structures into strong, metallic titanium objects.

                          

                                                   

The marriage of printing and origami techniques allows for greater structural complexity – such as the crane’s overhanging wings, a feature not producible by direct printing methods alone. In addition, Lewis’ team can print sheets with a variety of patterns, adding yet another level of architectural detail.

“By combining these methods, you can rapidly assemble very complex structures that simply cannot be made by conventional fabrication methods,” Lewis said.

Next, the team hopes to expand its origami repertoire to include much larger and much smaller structures, with an expanding array of inks. For example, the method can be extended to a variety of other ceramics and metals ranging from steels to nickel- and cobalt-based alloys to refractory and noble metals, according to Dunand.

The researchers also plan to explore possible applications including lightweight structures, biomedical devices, sensors and more.

“We’ve really just begun to unleash the power of this approach,” Lewis said.

Satellites Unlock Secret To Northern India's Vanishing Water

Using satellite data, UC Irvine and NASA hydrologists have found that groundwater beneath northern India has been receding by as much as 1 foot per year over the past decade – and they believe human consumption is almost entirely to blame.

The map shows groundwater changes in India during 2002-08, with losses in red and gains in blue, based on GRACE satellite observations. The estimated rate of depletion of groundwater in northwestern India is 4.0 centimeters of water per year, equivalent to a water table decline of 33 centimeters per year. Increases in groundwater in southern India are due to recent above-average rainfall, whereas rain in northwestern India was close to normal during the study period. (Credit: I. Velicogna/UC Irvine)

     More than 109 cubic kilometers (26 cubic miles) of groundwater disappeared from the region's aquifers between 2002 and 2008 – double the capacity of India's largest surface-water reservoir, the Upper Wainganga, and triple that of Lake Mead, the largest manmade reservoir in the U.S.

     People are pumping northern India's underground water, mostly to irrigate cropland, faster than natural processes can replenish it, said Jay Famiglietti and Isabella Velicogna, UCI Earthsystem scientists, and Matt Rodell of NASA's Goddard Space Flight Center.

     "If measures are not soon taken to ensure sustainable groundwater usage, consequences for the 114 million residents of the region may include a collapse of agricultural output, severe shortages of potable water, conflict and suffering," said Rodell, lead author of the study and former doctoral student of Famiglietti's at the University of Texas at Austin.

Study results will be published online Aug. 12 in the journal Nature.

     Groundwater comes from the percolation of precipitation and other surface waters down through Earth's soil and rock, accumulating in aquifers – cavities and layers of porous rock, gravel, sand or clay. In some subterranean reservoirs, the water may be thousands to millions of years old; in others, water levels decline and rise again naturally each year.

     Groundwater levels do not respond to changes in weather as rapidly as lakes, streams and rivers do. So when groundwater is pumped for irrigation or other uses, restoration of original levels can take months or years.

     "Groundwater mining – that is when withdrawals exceed replenishment rates – is a rapidly growing problem in many of the world's large aquifers," Famiglietti said. "Since groundwater provides nearly 80 percent of the water required for irrigated agriculture, diminishing groundwater reserves pose a serious threat to global food security."

     Data provided by India's Ministry of Water Resources had suggested that groundwater use across the nation was exceeding natural replenishment, but the regional rate of depletion had been unknown.

     In the new study, the hydrologists analyzed six years of monthly data for northern India from twin satellites called GRACE – NASA's Gravity Recovery and Climate Experiment – to produce a chronology of underground water storage changes.

     GRACE detects differences in gravity brought about by fluctuations in water mass, including water below the Earth's surface. As the satellites orbit 300 miles above Earth, their positions change – relative to each other – in response to variations in the pull of gravity. They fly about 137 miles apart, and microwave ranging systems measure every microscopic variance in the distance between the two.

     "With GRACE, we can monitor water storage changes everywhere in the world from our desk," said Velicogna, also with NASA's Jet Propulsion Laboratory. "The satellites allow us to observe how water storage evolves from one month to the next in critical areas of the world."

     Groundwater loss in northern India is particularly alarming because there were no unusual trends in rainfall – in fact, it was slightly above normal during the study period. The researchers also examined data on soil moisture, lake and surface reservoir storage, vegetation and glaciers in the nearby Himalayas to confirm that the apparent groundwater trend was real. The only influence they couldn't rule out was human.

     "For the first time, we can observe water use on land with no additional ground-based data collection," Famiglietti said. "This is critical because in many developing countries, where hydrological data are both sparse and hard to access, space-based methods provide perhaps the only opportunity to assess changes in freshwater availability across large regions."

     About GRACE: The Gravity Recovery and Climate Experiment is a partnership between NASA and the German Aerospace Center. The University of Texas Center for Space Research, Austin, has overall mission responsibility. NASA's Jet Propulsion Laboratory developed the twin satellites. The German Aerospace Center provided the launch, and GeoForschungsZentrum Potsdam, Germany, operates GRACE.

Crackling with Solar Flares

     Fast-growing sunspot 1112 is crackling with solar flares. So far, none of the blasts has hurled a substantial CME, or coronal mass ejection, toward Earth. In addition, a vast filament of magnetism is cutting across the sun's southern hemisphere. This filament is so large it spans a distance greater than the separation of Earth and the moon. A bright 'hot spot' just north of the filament's midpoint is UV radiation from sunspot 1112. The proximity is no coincidence; the filament appears to be rooted in the sunspot below. If the sunspot flares, it could cause the entire structure to erupt. Thus far, none of the flares has destabilized the filament. 

Human Brain Can 'See' Shapes With Sound

       Scientists at The Montreal Neurological Institute and Hospital -- The Neuro, McGill University have discovered that our brains have the ability to determine the shape of an object simply by processing specially-coded sounds, without any visual or tactile input. Not only does this new research tell us about the plasticity of the brain and how it perceives the world around us, it also provides important new possibilities for aiding those who are blind or with impaired vision.

New research shows that the human brain is able to 
determine the shape of an object simply by processing 
specially-coded sounds, without any visual or tactile input. 
(Credit: iStockphoto/Sergey Chushkin)

          Shape is an inherent property of objects existing in both vision and touch but not sound. Researchers at The Neuro posed the question 'can shape be represented by sound artificially?' "The fact that a property of sound such as frequency can be used to convey shape information suggests that as long as the spatial relation is coded in a systematic way, shape can be preserved and made accessible -- even if the medium via which space is coded is not spatial in its physical nature," says Jung-Kyong Kim, PhD student in Dr. Robert Zatorre's lab at The Neuro and lead investigator in the study.

       In other words, similar to our ocean-dwelling dolphin cousins who use echolocation to explore their surroundings, our brains can be trained to recognize shapes represented by sound and the hope is that those with impaired vision could be trained to use this as a tool. In the study, blindfolded sighted participants were trained to recognize tactile spatial information using sounds mapped from abstract shapes. Following training, the individuals were able to match auditory input to tactually discerned shapes and showed generalization to new auditory-tactile or sound-touch pairings.

      "We live in a world where we perceive objects using information available from multiple sensory inputs," says Dr. Zatorre, neuroscientist at The Neuro and co-director of the International Laboratory for Brain Music and Sound Research. "On one hand, this organization leads to unique sense-specific percepts, such as colour in vision or pitch in hearing. On the other hand our perceptual system can integrate information present across different senses and generate a unified representation of an object. We can perceive a multisensory object as a single entity because we can detect equivalent attributes or patterns across different senses." Neuroimaging studies have identified brain areas that integrate information coming from different senses -- combining input from across the senses to create a complete and comprehensive picture.

       The results from The Neuro study strengthen the hypothesis that our perception of a coherent object or event ultimately occurs at an abstract level beyond the sensory input modes in which it is presented. This research provides important new insight into how our brains process the world as well as new possibilities for those with impaired senses.

         The study was published in the journal Experimental Brain Research. The research was supported by grants from the Canadian Institutes of Health Research and the Natural Sciences and Engineering Research Council of Canada.

Start Your Car With Your Fingerprint

    Paranoid about getting your car stolen or just generally hate using keys? Well now, you can get this biometric vehicle starter that will start your car after reading your fingerprint. Maybe it’s overkill, but come on, if you can’t get girls with a biometric car starter then you’ve got bigger problems.

     When your fingerprint is identified by the system it then looks for pulse, blood pressure, and body temperature. Finally it scans the capillary patterns under the skin. The entire process only takes milliseconds to complete, and the system has verified the input was made by an actual living person. Advanced features of the Fingerprint Starter include Access Control, Ignition Interrupt, Computer Override, and Fuel Pump Cut-Off. Only those drivers with enrolled fingerprints can start the engine or enable/disable system features.