Science blog

June 5, 2011, 8:56 PM CT

Trapping antihydrogen atoms

Trapping antihydrogen atoms
Artist's image of the ALPHA trap which captured and stored antihydrogen atoms.

Credit: Chukman So

Trapping antihydrogen atoms at the European Organization for Nuclear Research (CERN) has become so routine that physicists are confident that they can soon begin experiments on this rare antimatter equivalent of the hydrogen atom, as per scientists at the University of California, Berkeley.

"We've trapped antihydrogen atoms for as long as 1,000 seconds, which is forever" in the world of high-energy particle physics, said Joel Fajans, UC Berkeley professor of physics, faculty scientist at Lawrence Berkeley National Laboratory and a member of the ALPHA (Antihydrogen Laser Physics Apparatus) experiment at CERN in Geneva, Switzerland.

The ALPHA team is hard at work building a new antihydrogen trap with "the hope that by 2012 we will have a new trap with laser access to allow spectroscopic experiments on the antiatoms," he said.

Fajans and the ALPHA team, which includes Jonathan Wurtele, UC Berkeley professor of physics, will publish their latest successes online on June 5 in advance of print publication in the journal Nature Physics Fajans, Wurtele and their graduate students played major roles in designing the antimatter trap and other aspects of the experiment.

Their paper reports that in a series of measurements last year, the team trapped 112 antiatoms for times ranging from one-fifth of a second to 1,000 seconds, or 16 minutes and 40 seconds.........

Posted by: Nora      Read more         Source

March 31, 2011, 7:11 AM CT

Leap to whole-cell simulations

Leap to whole-cell simulations
Using data supplied by researchers at the Max Planck Institute, University of Illinois postdoctoral researcher Elijah Roberts and chemistry professor Zaida Luthey-Schulten built a computer model of a bacterial cell that accurately simulates the behavior of living cells.

Credit: L. Brian Stauffer

Scientists have built a computer model of the crowded interior of a bacterial cell that � in a test of its response to sugar in its environment � accurately simulates the behavior of living cells.

The new "in silico cells" are the result of a collaboration between experimental researchers at the Max Planck Institute of Biology in Gera number of and theoretical researchers at the University of Illinois using the newest GPU (graphics processing unit) computing technology.

Their study appears in the journal PLoS Computational Biology

"This is the first time that we're modeling entire cells with the complete contents of the cellular cytoplasm represented," said Illinois postdoctoral researcher and main author Elijah Roberts. "We're looking at the influence of the whole cellular architecture instead of modeling just a portion of the cell, as people have done previously".

University of Illinois chemistry professor Zaida Luthey-Schulten, who led the research, had done molecular dynamics simulations of individual molecules or groups of molecules involved in information processing, but never of a system as large and complex as the interior of an entire cell.

Then in 2006 she saw a paper by Wolfgang Baumeister and colleagues at Max Planck that located every one of a bacterium's ribosomes, its protein-building machines, inside the cell.........

Posted by: Nora      Read more         Source

March 28, 2011, 7:16 AM CT

Will we hear the light?

Will we hear the light?
University of Utah bioengineer Richard Rabbitt led two new studies that made a surprising discovery: an invisible wavelength of infrared light can make rat heart cells beat and cause toadfish inner-ear cells to send signals to the brain. The discovery points the way to possible development of implanted devices that can use infrared light instead of electric signals to help deaf people hear -- a new form of cochlear implant -- help blind people see and treat movement and balance disorders.

Credit: Lee Siegel, University of Utah.

University of Utah researchers used invisible infrared light to make rat heart cells contract and toadfish inner-ear cells send signals to the brain. The discovery someday might improve cochlear implants for deafness and lead to devices to restore vision, maintain balance and treat movement disorders like Parkinson's.

"We're going to talk to the brain with optical infrared pulses instead of electrical pulses," which now are used in cochlear implants to provide deaf people with limited hearing, says Richard Rabbitt, a professor of bioengineering and senior author of the heart-cell and inner-ear-cell studies published this month in The Journal of Physiology

The studies � funded by the National Institutes of Health � also raise the possibility of developing cardiac pacemakers that use optical signals rather than electrical signals to stimulate heart cells. But Rabbitt says that because electronic pacemakers work well, "I don't see a market for an optical pacemaker at the present time".

The scientific significance of the studies is the discovery that optical signals � short pulses of an invisible wavelength of infrared laser light delivered via a thin, glass optical fiber � can activate heart cells and inner-ear cells correlation to balance and hearing.........

Posted by: Nora      Read more         Source

March 26, 2011, 10:19 PM CT

More Efficient Solar Panels

More Efficient Solar Panels
Illustration of multiple-exciton generation (MEG), a theory that suggests it is possible for an electron that has absorbed light energy, called an exciton, to transfer that energy to more than one electron, resulting in more electricity from the same amount of absorbed light. The left side shows an electron promoted to a high energy state (blue) plus the "hole" vacated by the electron (red). The right side shows the original exciton (now dark green/red) and a new exciton (light green/orange) after MEG. The top image shows a conceptualized version of the idea, while the bottom shows an actual exciton and bi-exciton using the same color scheme.

Credit: Mark T. Lusk, Department of Physics, Colorado School of Mines

Studies done by Mark Lusk and his colleagues at the Colorado School of Mines could significantly improve the efficiency of solar cells. Their latest work describes how the size of light-absorbing particles--quantum dots--affects the particles' ability to transfer energy to electrons to generate electricity.

The results are reported in the recent issue of the journal ACS Nano.

The advance provides evidence to support a controversial idea, called multiple-exciton generation (MEG), which theorizes that it is possible for an electron that has absorbed light energy, called an exciton, to transfer that energy to more than one electron, resulting in more electricity from the same amount of absorbed light.

Quantum dots are man-made atoms that confine electrons to a small space. They have atomic-like behavior that results in unusual electronic properties on a nanoscale. These unique properties appears to be especially valuable in tailoring the way light interacts with matter.

Experimental verification of the link between MEG and quantum dot size is a hot topic due to a large degree of variation in previously published studies. The ability to generate an electrical current following MEG is now receiving a great deal of attention because this will be a necessary component of any commercial realization of MEG.........

Posted by: Nora      Read more         Source

March 18, 2011, 10:15 PM CT

Ecologists use 70-year-old pressed plants

Ecologists use 70-year-old pressed plants
More than half of the world's population now lives in cities, yet we know little about how urbanization affects biodiversity. In one the first studies of its kind, ecologists in Indianapolis, USA have used 70 year-old dried plant specimens to track the impact of increasing urbanization on plants. The results are published this week in the British Ecological Society's Journal of Ecology

Lead by Dr Rebecca Dolan, director of the Friesner Herbarium, Butler University, the team examined 2,800 dried plants collected around Indianapolis before 1940 and compared these with plants they and their students found at 16 field sites between 1996 and 2006.

They discovered that increasing urbanization has wrought major changes to Indianapolis's plant species. Eventhough the city supports a similar number of plant species � around 700 � today's flora has fewer native plants and more non-native species, which have been introduced from other parts of the world and are now spreading on their own.

The study observed that over the past 70 years, Indianapolis's native plants have been lost at a rate of 2.4 species per year, while over the same period 1.4 non-natives arrive each year. As per Dolan: "This study shows that our flora is becoming less distinctive".

Plants now lost to Indianapolis include Queen-of-the-prairie (Filipendula rubra), a member of the rose family with fantastic wands of pink flowers. It was last found growing in a damp spot by the Water Canal at 52nd Street in July 1935. Another loss is the Virginia bunchflower (Melanthium virginicum), a member of the lily family with striking stalks of white flowers.........

Posted by: Nora      Read more         Source

March 15, 2011, 10:36 PM CT

Tying the knot with computer-generated holograms

Tying the knot with computer-generated holograms
A laser beam is imprinted with a hologram in the input pupil of an objective lens. The hologram is projected through the objective's focal plane and comes to a focus along a 3-D curve parameterized by its arc length, s.

Credit: Optics Express

In the latest twist on optical knots, New York University (NYU) physicists have discovered a new method to create extended and knotted optical traps in three dimensions. This method, which the NYU researchers describe in the Optical Society's (OSA) open-access journal Optics Express, produces "bright" knots, where the maximum of the light intensity traces out a knotted trajectory in space, for the first time allowing microscopic objects to be trapped along the path of the knot. The method may even, one day, help enable fusion energy as a practical power source, as per the NYU team.

Optical traps can be used to confine and manipulate small objects�ranging in size from a few nanometers to several hundred micrometers�in 3-D. They work because variations in the intensity of the light produce forces that push small objects toward bright regions. The trapping of small objects is widely used for a broad range of research applications in biophysics, condensed matter physics and medical diagnostics.

Ordinary optical traps use Gaussian laser beams that focus to a spot. The beams being used to create extended optical traps focus instead to curves, much like the bright patterns on the bottom of swimming pools. And these bright curves can be tied in knots.

Knotted traps are made by imprinting a computer-generated hologram on the wavefronts of an otherwise ordinary beam of light. NYU undergraduate student Elisabeth Shanblatt and NYU physicist David Grier, the authors of the Optics Express paper, use a "liquid-crystal spatial light modulator" to project their holograms. This is essentially the first cousin of a conventional LCD television screen. The spatial light modulator imprints a calculated pattern of phase shifts onto the light. When the modified beam is brought to a focus with a high-power lens, the region of maximum intensity takes the form of a 3-D curve. This curve can cross over and through itself to trace out a knot. Moreover, the same hologram can redirect the light's radiation pressure to have a component along the curve, so that the total optical force "threads the knot".........

Posted by: Nora      Read more         Source

March 15, 2011, 7:35 AM CT

Hubble Rules Out One Alternative to Dark Energy

Hubble Rules Out One Alternative to Dark Energy
The brilliant, blue glow of young stars trace the graceful spiral arms of galaxy NGC 5584 in this Hubble Space Telescope image. Thin, dark dust lanes appear to be flowing from the yellowish core, where older stars reside. The reddish dots sprinkled throughout the image are largely background galaxies. Credit: NASA, ESA, A. Riess (STScI/JHU), L. Macri (Texas A&M University), and Hubble Heritage Team (STScI/AURA)
Astronomers using NASA's Hubble Space Telescope have ruled out an alternate theory on the nature of dark energy after recalculating the expansion rate of the universe to unprecedented accuracy.

The universe may be expanding at an increasing rate. Some think that is because the universe is filled with a dark energy that works in the opposite way of gravity. One alternative to that hypothesis is that an enormous bubble of relatively empty space eight billion light-years across surrounds our galactic neighborhood. If we lived near the center of this void, observations of galaxies being pushed away from each other at accelerating speeds would be an illusion.

This hypothesis has been invalidated because astronomers have refined their understanding of the universe's present expansion rate. Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University in Baltimore, Md., led the research. The Hubble observations were conducted by the SHOES (Supernova Ho for the Equation of State) team that works to refine the accuracy of the Hubble constant to a precision that allows for a better characterization of dark energy's behavior. The observations helped determine a figure for the universe's current expansion rate to an uncertainty of just 3.3 percent. The new measurement reduces the error margin by 30 percent over Hubble's prior best measurement of 2009. Riess' results appear in the April 1 issue of The Astrophysical Journal.........

Posted by: Edwin      Read more         Source

March 7, 2011, 7:05 AM CT

Key to immune response

Key to immune response
Dr. Axel Kallies from the Walter and Eliza Hall Institute in Melbourne, Australia, and his colleagues have used molecular signatures to identify a key cell population responsible for regulating the body's immune response.

Credit: Walter and Eliza Hall Institute

Researchers from the Walter and Eliza Hall Institute have identified the key immune cell population responsible for regulating the body's immune response.

The finding could have wide-ranging repercussions for the therapy of autoimmune diseases, organ transplantation and cancer, and change how the efficacy of newly developed drugs is measured.

The discovery was made by Dr Erika Cretney, Dr Axel Kallies and Dr Stephen Nutt from the institute's Molecular Immunology division. It centred on a population of immune cells called regulatory T cells.

Regulatory T cells (T-regs) are responsible for limiting the immune response. Disorders that decrease T-reg activity can lead to autoimmune disorders such as type 1 diabetes or coeliac disease, while increased T-reg activity can suppress the immune system when it should be actively killing malignant or infected cells.

Dr Kallies said the research team had used molecular signatures to identify which cells within the regulatory T cell population were responsible for suppressing immune responses.

"It turns out that the bulk of cells which are classified as regulatory T cells may not do much," Dr Kallies said. "In this study we have identified a distinct group of effector regulatory T cells, or 'active T-regs', which are the key drivers of immune response regulation".........

Posted by: John      Read more         Source

March 7, 2011, 7:02 AM CT

Alcoholic drinks to induce superconductivity

Alcoholic drinks to induce superconductivity
Japanese scientists have been immersing iron-based compounds in hot alcoholic beverages such as red wine, sake and shochu to induce superconductivity.

Researchers from the National Institute for Materials Science, Japan, observed that immersing pellets of an iron-based compound in heated alcoholic beverages for 24 hours greatly increase their superconducting ability.

Iron-based compounds commonly become superconductive after being exposed to air. This process however can take up to several months. This study demonstrated that superconductivity can be induced in just one day.

Due to the variety of technological applications of superconducting materials, there has been a scramble for substances that may induce and enhance superconductivity in iron-based compounds.

The alcoholic beverages used were red and white wine, beer, Japanese sake, shochu, and whisky. Samples of the iron-based compound were immersed in each beverage, heated at 70oC for 24 hours, and then analysed.

Red wine was shown to induce the best superconducting properties; however beverages with the same alcohol concentration showed a significant difference. This suggests that it may not be the alcohol contributing to the creation of superconductivity but instead another component present in the beverages.........

Posted by: John      Read more         Source

March 6, 2011, 10:03 AM CT

The Freshest laptop designs

The Freshest laptop designs
With aesthetics becoming almost as important a factor in usability and performance when it comes to buying a laptop these days, manufacturers are using teams of consultants to get the design just right for a particular market before they even start putting the parts together. Business users will be looking for something that projects a corporate image of sleek efficiency, often in matt black, whereas teenagers will be more interested in bright colours and funky originality, and there is a whole raft of different requirements in between. Laptop news covers the latest designs in innovative laptops to hit the market in recent months.

Notebooks are becoming increasingly lighter and thinner, and taking on the role of fashion accessories to project a personal image as well as sophisticated machines for processing data and keeping in touch with friends and colleagues.

Intel's Core-i technology is at the heart of the laptop revolution, with these ultra-fast and ultra-small microprocessors allowing for ever-smaller designs and increased performance. They are fitted into a whole range of electronic devices apart from laptops, from digital signs to automated machines. Fitting them into laptops allows the kit to work anywhere up to three times faster than those using the Core 2 technology of older ranges.........

Posted by: John      Read more         Source

Sun, 30 Jan 2011 17:07:03 GMT

Averrhoa bilimbi

Averrhoa bilimbi
Today"s entry was written by Claire:

3Point141@Flickr provided us with this photograph via the BPotD Flickr Pool of the fruit and flowers of Averrhoa bilimbi, a tropical tree belonging to Oxalidaceae (taken in Pinellas Park, Florida). Much appreciated 3Point141!

Oxalidaceae, or the wood sorrels, is a small family of 6 genera and 770 species distributed in temperate to tropical regions. Common to the family, and also visible with the flowers of Averrhoa bilimbi in the photograph, there are five petals and stamens in multiples of five in the whorl.

Averrhoa bilimbi (named after Averroes, a Muslim astronomer and philosopher) is a long-lived tree that produces an edible, refreshing fruit. Some common names of this species are (funnily enough) bilimbi, cucumber tree, and pickle fruit - the latter two attesting to what the fruit resembles. Averrhoa bilimbi is often compared with another popular, cultivated tree in the same genus called Averrhoa carambola, which most people know as starfruit or carambola.

The species likely originated on the Maluku Islands of Indonesia, but varieties are now commonly found throughout southeast Asia and other tropical areas worldwide. It has been cultivated in tropical regions for centuries and has accumulated a swath of local common names: Averrhoa bilimbi nomenclature via Wikipedia.

Averrhoa bilimbi can often reach heights of ten meters or higher. It can be found in gardens for ornamental purposes (as you can see, the flowers are very exotic) but it is typically grown for local production of food. The fruit is quite acidic and cannot always be eaten raw (though it is sometimes a snacking food). Fruits can also be sweet or savoury depending on the cultivated variety. Pickling, cooking, sugaring, currying, and juicing are some ways Averrhoa bilimbi is used in local cuisine.

Ecology resource link (added by Daniel): Frequent BPotD contributor, Eric in S.F., suggested a note regarding a newly-immigrated kudzu-eating bug in the southeast USA. Kudzu (Pueraria lobata), a member of the Fabaceae, is an invasive scourge in southeast USA. One would think that a kudzu-eating insect would be welcome, but it turns out that it also happily feeds on soybean and peanuts (also Fabaceae), causing a potential threat to those industries. Also, residents are concerned that the rather-smelly bugs can cause quite the odour when they congregate in the thousands. Read more via Alabama Cooperative Extension: State"s Residents Should Be on Watch for Kudzu Eating Insect.

Posted by: Daniel Mosquin      Read more     Source

January 28, 2011, 8:12 PM CT

Air laser may sniff bombs, pollutants from a distance

Air laser may sniff bombs, pollutants from a distance
Researchers at Princeton University developed a technique for generating a laser beam out of nothing but air. They focus a pump laser on a distant point in the air and another laser beam comes back. The image shows a pulse of infra-red light from this "air laser." The center region represents the highest intensity; the outer areas have lower intensity light. The technique could be used for sensing minute quantities of gas in the air from a distance.

Credit: Image courtesy Arthur Dogariu, Princeton University

Princeton University engineers have developed a new laser sensing technology that may allow soldiers to detect hidden bombs from a distance and researchers to better measure airborne environmental pollutants and greenhouse gasses.

"We are able to send a laser pulse out and get another pulse back from the air itself," said Richard Miles, a professor of mechanical and aerospace engineering at Princeton, the research group leader and co-author on the paper. "The returning beam interacts with the molecules in the air and carries their finger prints".

The new technique differs from prior remote laser-sensing methods in that the returning beam of light is not just a reflection or scattering of the outgoing beam. It is an entirely new laser beam generated by oxygen atoms whose electrons have been "excited" to high energy levels. This "air laser" is a much more powerful tool than previously existed for remote measurements of trace amounts of chemicals in the air.

The researchers, whose work is funded by the Office of Naval Research's basic research program on Sciences Addressing Asymmetric Explosive Threats, published their new method Jan. 28 in the journal Science

Miles collaborated with three other researchers: Arthur Dogariu, the main author on the paper, and James Michael of Princeton, and Marlan Scully, a professor with joint appointments at Princeton and Texas A&M University.........

Posted by: Nora      Read more         Source

January 16, 2011, 10:41 AM CT

Putting the Dead to Work

Putting the Dead to Work
Conservation paleobiologists--researchers who use the fossil record to understand the evolutionary and ecological responses of present-day species to changes in their environment--are putting the dead to work.

A new review of the research in this emerging field provides examples of how the fossil record can help assess environmental impacts, predict which species will be most vulnerable to environmental changes, and provide guidelines for restoration.

The literature review by conservation paleobiologists Gregory Dietl of the Paleontological Research Institution and Cornell University and Karl Flessa of the University of Arizona is reported in the January, 2011, issue of the journal Trends in Ecology and Evolution.

The National Science Foundation (NSF) funded the research.

"Conservation paleobiologists apply the data and tools of paleontology to today's problems in biodiversity conservation," says Dietl.

The primary sources of data are "geohistorical": the fossils, geochemistry and sediments of the geologic record.

"A conservation paleobiology perspective has the unique advantage of being able to identify phenomena beyond time scales of direct observation," Dietl says.

Such data, says Flessa, "are crucial for documenting the species we have already lost--such as the extinct birds of the Hawaiian islands--and for developing more effective conservation policies in the face of an uncertain future.".........

Posted by: Nora      Read more         Source

January 11, 2011, 6:52 AM CT

Debunking Solar Energy Efficiency Measurements

Debunking Solar Energy Efficiency Measurements
In recent years, developers have been investigating light-harvesting thin film solar panels made from nanotechnology - and promoting efficiency metrics to make the technology marketable. Now a Tel Aviv University researcher is providing new evidence to challenge recent "charge" measurements for increasing solar panel efficiency.

Offering a less expensive, smaller solution than traditional panels, Prof. Eran Rabani of Tel Aviv University's School of Chemistry at the Raymond and Beverly Sackler Faculty of Exact Sciences puts a lid on some current hype that promises to increase efficiencies in thin film panels. His research, published recently in the journals Nano Letters and Chemical Physics Letters, may bring the development of new solar energy technologies more down to earth.

Prof. Rabani combines a new theoretical approach with computer simulations. "Our theory shows that current predictions to increase efficiencies won't work. The increase in efficiencies cannot be achieved yet through Multiexciton Generation, a process by which several charge carriers (electrons and holes) are generated from one photon," he says.

Inefficient as "charged"

But both new and existing theories bode well for the development of other strategies in future solar energy technology, he points out. Newer approaches published in journals such as Science may provide means for increasing the efficiencies of solar technology, and perhaps would also be useful in storage of solar energy, Prof. Rabani and his team of scientists believe.........

Posted by: Nora      Read more         Source

Mon, 10 Jan 2011 03:30:29 GMT

Geastrum saccatum

Geastrum saccatum
Thanks once again to Robert Klips (Orthotrichum@Flickr) for sharing one of his photograph with BPotD (original via the BPotD Flickr Pool). Much appreciated!

Though these may appear to be acorns rapidly fired into small bits of cookie dough, they are actually the fruiting bodies of the rounded earthstar, Geastrum saccatum. Geastrum literally translates to earth star, and the genus has a cosmopolitan temperate and tropical distribution. Geastrum saccatum contributes to that broad range, as it is the most widespread species.

As Robert explains in his comments on Flickr, earthstars resemble puffballs when the fruiting bodies first begin to develop. As it matures, the outer skin (outer peridium) splits and peels back, forming the star pattern. In some species, the shape and length of the segments of the outer peridium are enough to elevate the inner spore sac away from the ground, but in the case of Geastrum saccatum, the fruiting body remains relatively flat and close to the ground (or as Michael Kuo describes in a linked article above, the spore case "sits directly on the arms, as though in a bowl (without a pedestal)".

Geastrum saccatum is a saprobe, gaining its nutrients from dead or decaying organic matter.

No, it"s not edible.

Posted by: Daniel Mosquin      Read more     Source

December 29, 2010, 6:11 AM CT

Protein helps parasite survive in host cells

Protein helps parasite survive in host cells
Wandy Beatty
Toxoplasma gondii and other related parasites surround themselves with a membrane to protect against factors in host cells that would otherwise kill them. Scientists at Washington University School of Medicine in St. Louis have identified a parasite protein that protects this membrane from host proteins that can rupture it. Accoding to the researchers, disabling the parasite's defensive protein could help give hosts an advantage in the battle against infection.
Scientists at Washington University School of Medicine in St. Louis have learned why changes in a single gene, ROP18, contribute substantially to dangerous forms of the parasite Toxoplasma gondii. The answer has likely moved science a step closer to new ways to beat Toxoplasma and a number of other parasites.

As per a research findings published in Cell Host & Microbe, researchers show that the ROP18 protein disables host cell proteins that would otherwise pop a protective bubble the parasite makes for itself. The parasite puts the bubble on like a spacesuit by forming a membrane around itself when it enters host cells. This protects it from the hostile environment inside the cell, which would otherwise kill it.

"If we can find therapies that block ROP18 and other parasite proteins like it, that could give the host the upper hand in the battle against infection," says first author Sarah Fentress, a graduate student in the laboratory of L. David Sibley, PhD, professor of molecular microbiology.

Infection with Toxoplasma, or toxoplasmosis, is most familiar to the general public from the recommendation that pregnant women avoid changing cat litter. Cats are usually infected with the parasite, as are some livestock and wildlife.

"The exact role of ROP18 and related proteins in human disease remains to be studied," says Sibley. "But mice are natural hosts of Toxoplasma, so studies in laboratory mice are relevant to the spread of infection".........

Posted by: Nora      Read more         Source

December 25, 2010, 10:37 AM CT

How cells running on empty trigger fuel recycling?

How cells running on empty trigger fuel recycling?
When the process of autophagy is defective, cells are unable to recycle cellular organelles such as mitochondria (shown in red) to generate molecular building blocks when needed. Cell nuclei are shown in blue.

Credit: Daniel Egan, Salk Institute for Biological Studies

Scientists at the Salk Institute for Biological Studies have discovered how AMPK, a metabolic master switch that springs into gear when cells run low on energy, revs up a cellular recycling program to free up essential molecular building blocks in times of need.

In a paper reported in the Dec. 23, 2010 edition of Science Express, a team led by Reuben Shaw, PhD., Howard Hughes Medical Institute Early Career Scientist and Hearst Endowment assistant professor in the Salk's Molecular and Cell Biology Laboratory, reports that AMPK activates a cellular recycling process known as autophagy by activating an enzyme known as ATG1, that jumpstarts the process.

The newly uncovered direct molecular correlation between AMPK and ATG1 is significant because dysfunctions in both AMPK signaling and autophagy are implicated in a plethora of aging-related diseases, including type II diabetes, cancer, and neurodegenerative diseases such Parkinson's and Alzheimers.

Despite its ominous name�derived from "self" (auto) and "eating" (phagy)�cells use autophagy to dispose of debris before it becomes toxic enough to kill a cell. "Autophagy is an ancient process that evolved to break down components cells don't need to create things they do need," says Dan Egan, a graduate student in Shaw's lab and the study's first author.........

Posted by: Nora      Read more         Source

December 24, 2010, 1:36 PM CT

Nnew cell biological mechanism

Nnew cell biological mechanism
Dr. Edward De Robertis is a researcher at University of California -- Los Angeles.

Credit: UCLA

The cell signaling pathway known as Wnt, usually activated in cancers, causes internal membranes within a healthy cell to imprison an enzyme that is vital in degrading proteins, preventing the enzyme from doing its job and affecting the stability of a number of proteins within the cell, scientists at UCLA's Jonsson Comprehensive Cancer Center have found.

The finding is important because sequestering the enzyme, Glycogen Synthase Kinase 3 (GSK3), results in the stabilization of proteins in the cell, at least one of which is known to be a key player in cancer, said Dr. Edward De Robertis, senior author of the study and a Jonsson Cancer Center scientist.

"Surprisingly, we observed that the degradation of about 20 percent of proteins in the cell is triggered by the GSK3 enzyme," said De Robertis, who also is a Howard Hughes Medical Institute investigator. "That's a great a number of proteins and one of them, beta-Catenin, is known to cause cancer. We also know that Wnt signaling is activated in about 85 percent of colorectal cancers and other forms of cancer start with mutations that activate Wnt signaling. So, this finding could have ramifications for potential new therapys for cancer".

The study, a collaboration with cell biologist Dr. David D. Sabatini of New York University, appears in the Dec. 23, 2010 issue of the peer-evaluated journal Cell........

Posted by: Nora      Read more         Source

December 21, 2010, 6:36 AM CT

Global rivers emit greenhouse gas nitrous oxide

Global rivers emit greenhouse gas nitrous oxide
The Corralles drainage ditch in Albuquerque, N.M., was one of 72 study sites in the research.

Credit: Chelsea Crenshaw

What goes in must come out, a truism that now may be applied to global river networks.

Human-caused nitrogen loading to river networks is a potentially important source of nitrous oxide emission to the atmosphere. Nitrous oxide is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction.

It happens via a microbial process called denitrification, which converts nitrogen to nitrous oxide and an inert gas called dinitrogen.

When summed across the globe, scientists report this week in the journal Proceedings of the National Academy of Sciences (PNAS), river and stream networks are the source of at least 10 percent of human-caused nitrous oxide emissions to the atmosphere.

That's three times the amount estimated by the Intergovernmental Panel on Climate Change (IPCC).

Rates of nitrous oxide production via denitrification in small streams increase with nitrate concentrations.

"Human activities, including fossil fuel combustion and intensive agriculture, have increased the availability of nitrogen in the environment," says Jake Beaulieu of the University of Notre Dame and the U.S. Environmental Protection Agency in Cincinnati, Ohio, and lead author of the PNAS paper.

"Much of this nitrogen is transported into river and stream networks," he says, "where it may be converted to nitrous oxide, a potent greenhouse gas, via the activity of microbes".........

Posted by: Nora      Read more         Source

December 16, 2010, 8:03 AM CT

Soft substrate promotes pluripotent stem cell culture

Soft substrate promotes pluripotent stem cell culture
Photo by
L. Brian Stauffer

Illinois researchers developed a soft growth medium for stem cells that allows them to culture homogenious pluripotent colonies, without expensive growth factor chemicals. The team: front row from left, graduate students Farhan Chowdhury and Yanzhen Li and visiting scholar Tamaki Yokohama-Tamaki; back row from left, graduate student Yeh Chuin Poh; Tetsuya Tanaka, professor of animal sciences; and Ning Wang, professor of mechanical science and engineering.

University of Illinois scientists have found a key to keeping stem cells in their neutral state: It takes a soft touch.

In a paper reported in the journal PLoS One, the scientists demonstrated that culturing mouse embryonic stem cells (mESCs) on a soft gel rather than on a hard plate or dish keeps them in their pluripotent state, a ground state with the ability to become any type of tissue. The soft substrate maintains homogeneous pluripotent colonies over long periods of time - without the need for expensive growth chemicals.

"This has huge applications in the future of regenerative medicine," said mechanical science and engineering professor Ning Wang, who co-led the group with animal sciences professor Tetsuya Tanaka. "It's an exciting area. There's still a lot of work to do, but our work is a step toward understanding the basic biology of stem cells".

The difficulty of maintaining mESC colonies that are homogeneously pluripotent has been one of the main obstacles in stem cell research. Pluripotent stem cells spontaneously differentiate, beginning to turn into specialized tissue types such as skin or muscle. Researchers use chemicals called growth factors to keep mESCs in their unchanged state, but even then it's not long before the culture is a mixture of cells in various stages of differentiation, with diverse gene expression and morphologies.........

Posted by: Nora      Read more         Source

December 15, 2010, 7:18 AM CT

Tiny channels carry big information

Tiny channels carry big information
Schematic of a 2-nm nanochannel device, with two microchannels, ten nanochannels and four reservoirs.

Credit: Image courtesy of Chuanhua Duan

They say it's the little things that count, and that certainly holds true for the channels in transmembrane proteins, which are small enough to allow ions or molecules of a certain size to pass through, while keeping out larger objects. Artificial fluidic nanochannels that mimic the capabilities of transmembrane proteins are highly prized for many advanced technologies. However, it has been difficult to make individual artificial channels of this size until now.

Scientists with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have been able to fabricate nanochannels that are only two nanometers (2-nm) in size, using standard semiconductor manufacturing processes. Already they've used these nanochannels to discover that fluid mechanics for passages this small are significantly different not only from bulk-sized channels, but even from channels that are merely 10 nanometers in size.

"We were able to study ion transport in our 2-nm nanochannels by measuring the time and concentration dependence of the ionic conductance," says Arun Majumdar,.

Director of DOE's Advanced Research Projects Agency Energy (ARPA-E), who led this research while still a scientist at Berkeley Lab. "We observed a much higher rate of proton and ionic mobility in our confined hydrated channels up to a fourfold increase over that in larger nanochannels (10-to-100 nm). This enhanced proton transport could explain the high throughput of protons in transmembrane channels".........

Posted by: Nora      Read more         Source

December 10, 2010, 11:34 PM CT

Deals on Electronics, Watches, Family Products

Deals on Electronics, Watches, Family Products
New York (12/10/2010)-For perpetual bargain hunters and other shoppers looking to get a great deal on the latest electronics, brand name watches, wireless accessories, jewelry and more, is the lowest-priced deal-of-the-day website offering unheard-of exclusive deals on just a single item and only for 24 hours. To keep customers coming back for more, even offers surprise free products once or twice a week.

As the largest independently-owned daily deal site in the world, leverages its tremendous buying power with major brands and retailers plus a dedicated team of competitive price-comparison experts to offer outrageous deals to more than 350,000 daily site visitors, like a Magellan Roadmate GPS, HD camcorder or 12 MP digital camera-all of which recently sold for just $39.99.

How offer such amazing prices? Rather than spend precious dollars on marketing to attract new customers, 1SaleaDay focuses on giving deep savings to customers, who then pass the word on about the great deals they've discovered at the site.

"Thousands of customers make their first web stop of the day to see what's hot and get the best deal on the products they want at a price anyone can afford," said Ben Federman CEO of "Collectors, gadget geeks and even parents and grandparents check us out first to get the best deals anywhere on the web on gifts for their kids or grandkids - or even for themselves."........

Posted by: John      Read more         Source

December 8, 2010, 7:02 AM CT

Good grades in high school lead to better health

Good grades in high school lead to better health
MADISON The "A" grades that high schoolers earn aren't just good for making the honor roll they also make them healthier as adults, too.

Studies have long shown that education is associated with better health, but new research by Pamela Herd, an associate professor of public affairs and sociology at the University of Wisconsin-Madison, shows that higher academic performance in high school plays a critical role in better health throughout life.

"How well you do in school matters," Herd says about the findings, which were reported in the recent issue of the Journal of Health and Social Behavior "We already know it matters for things like your work and your earnings, but this proves it also matters for your health."

The finding may come years or decades after someone is in a position to do something to earn better grades. But for those who are still in school, there's every reason to believe the link between academic performance and health exists for younger people, too, Herd says.

The conclusion relies on data from the Wisconsin Longitudinal Study, a groundbreaking survey that has involved more than 10,000 graduates of Wisconsin's high school class of 1957 during the last 53 years. UW-Madison scientists have gone back to the class members six times since they graduated, asking questions about work, life, family and now, as the class ages, health.........

Posted by: Nora      Read more         Source

December 7, 2010, 7:42 AM CT

Imitating Someone's Accent

Imitating Someone's Accent
In conversation, we often imitate each other's speech style and may even change our accent to fit that of the person we're talking to. A recent study in Psychological Science, a journal of the Association for Psychological Science, suggests that imitating someone who speaks with a regional or foreign accent may actually help you understand them better.

"If people are talking to each other, they tend to sort of move their speech toward each other," says Patti Adank, of the University of Manchester, who cowrote the study with Peter Hagoort and Harold Bekkering from Radboud University Nijmegen in the Netherlands. People don't only do this with speech, she says. "People have a tendency to imitate each other in body posture, for instance in the way they cross their arms." She and her colleagues devised an experiment to test the effect of imitating and accent on subsequent comprehension of sentences spoken in that accent.

In the experiment, Dutch volunteers were first tested on how well they understood sentences spoken in an unfamiliar accent of Dutch. To make sure that all listeners were unfamiliar, a new accent was invented for the study, in which all the vowels were swapped (for instance 'ball' would become 'bale'). Next, each participant listened to 100 sentences in the unfamiliar accent. But first, they were given different instructions on how to respond to the sentences. Some were told to repeat the sentence, imitating the accent. Others were told either only to listen, to repeat the sentences in their own accent, or to transcribe the accented sentences as they had heard them, complete with strange vowels. Finally, the participants were tested again on how well they could understand sentences spoken in the unfamiliar accent.........

Posted by: Nora      Read more         Source

November 8, 2010, 7:26 AM CT

Taming thermonuclear plasma with a snowflake

Taming thermonuclear plasma with a snowflake
This is a "snowflake" divertor -- a novel plasma-material interface is realized in the National Spherical Torus Experiment.

Credit: V. Soukhanovskii, Lawrence Livermore National Laboratory

Physicists working on the National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Laboratory are now one step closer to solving one of the grand challenges of magnetic fusion researchhow to reduce the effect that the hot plasma has on fusion machine walls (or how to tame the plasma-material interface). Some heat from the hot plasma core of a fusion energy device escapes the plasma and can interact with reactor vessel walls. This not only erodes the walls and other components, but also contaminates the plasmaall challenges for practical fusion. One method to protect machine walls involves divertors, chambers outside the plasma into which the plasma heat exhaust (and impurities) flow. A new divertor concept, called the "snowflake," has been shown to significantly reduce the interaction between hot plasma and the cold walls surrounding it.

Strong magnetic fields shape the hot plasma in the form of a donut in a magnetic fusion plasma reactor called a tokamak. As confined plasma particles move along magnetic field lines inside the tokamak, some particles and heat escape because of instabilities in the plasma. Surrounding the hot plasma is a colder plasma layer, the scrape-off layer, which forms the plasma-material interface. In this layer, escaped particles and heat flow along an "open" magnetic field line to a separate part of the vessel and enter a "divertor chamber." If the.........

Posted by: John      Read more         Source

October 20, 2010, 7:37 AM CT

Curving 3D nanostructures

Curving 3D nanostructures
Twisting spires are one of the 3D shapes researchers at the University of Michigan were able to develop using a new manufacturing process.
Credit: A. John Hart
Twisting spires, concentric rings, and gracefully bending petals are a few of the new three-dimensional shapes that University of Michigan engineers can make from carbon nanotubes using a new manufacturing process.

The process is called "capillary forming," and it takes advantage of capillary action, the phenomenon at work when liquids seem to defy gravity and travel up a drinking straw of their own accord.

The new miniature shapes, which are difficult if not impossible to build using any material, have the potential to harness the exceptional mechanical, thermal, electrical, and chemical properties of carbon nanotubes in a scalable fashion, said A. John Hart, an assistant professor in the Department of Mechanical Engineering and in the School of Art & Design.

They could lead to probes that can interface with individual cells and tissues, novel microfluidic devices, and new materials with a custom patchwork of surface textures and properties.

A paper on the research is reported in the October edition of Advanced Materials, and is featured on the cover.

"It's easy to make carbon nanotubes straight and vertical like buildings," Hart said. "It hasn't been possible to make them into more complex shapes. Assembling nanostructures into three-dimensional shapes is a main goals of nanotechnology. The method of capillary forming could be applied to a number of types of nanotubes and nanowires, and its scalability is very attractive for manufacturing".........

Posted by: John      Read more         Source

October 18, 2010, 7:53 AM CT

Novel approach to food safety

Novel approach to food safety
M. Murat Dundar is an assistant professor of computer & information science in the School of Science at Indiana University-Purdue University Indianapolis.

Credit: School of Science at Indiana University-Purdue University Indianapolis
Technologies for rapid detection of bacterial pathogens are crucial to maintaining a secure food supply.

Scientists from the School of Science at Indiana University-Purdue University Indianapolis (IUPUI) and the Bindley Bioscience Center at Purdue University have developed a novel approach to automated detection and classification of harmful bacteria in food. The researchers have designed and implemented a sophisticated statistical approach that allows computers to improve their ability to detect the presence of bacterial contamination in tested samples. These formulas propel machine-learning, enabling the identification of known and unknown classes of food pathogens.

The study appears in the recent issue of the journal Statistical Analysis and Data Mining

"The sheer number of existing bacterial pathogens and their high mutation rate makes it extremely difficult to automate their detection," said M. Murat Dundar, Ph.D., assistant professor of computer science in the School of Science at IUPUI and the university's principal investigator of the study. "There are thousands of different bacteria subtypes and you can't collect enough subsets to add to a computer's memory so it can identify them when it sees them in the future. Unless we enable our equipment to modify detection and identification based on what it has already seen, we may miss discovering isolated or even major outbreaks." .........

Posted by: Nora      Read more         Source

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