This tiny worm became temporarily paralyzed when scientists fed it a light-sensitive material, or "photoswitch," and then exposed it to ultraviolet light.
Credit: American Chemical Society
In an advance with overtones of Star Trek phasers and other sci-fi ray guns, researchers in Canada are reporting development of an internal on-off "switch" that paralyzes animals when exposed to a beam of ultraviolet light. The animals stay paralyzed even when the light is turned off. When exposed to ordinary light, the animals become unparalyzed and wake up. Their study appears in the Journal of the American Chemical Society (JACS). It reports the first demonstration of such a light-activated switch in animals.
Neil Branda and his colleagues point out that such "photoswitches" light-sensitive materials that undergo photoreactions have been available for years. Researchers use them in research. Doctors use light-sensitive materials and photoreactions in medicine in photodynamic treatment to treat certain forms of cancer. Those light-sensitive materials, however, do not have the reversibility that exists in photoswitching.
The JACS report describes development and successful testing of a photoswitch composed of the light-sensitive material, dithienylethene. The researchers grew transparent, pinhead-sized worms (C. elegans) and fed them a dithienylethene. When exposed to ultraviolet light, the worms turned blue and became paralyzed. When exposed to visible light, the dithienylethene became colorless again and the worms' paralysis ended. A number of of the worms lived through the paralyze-unparalyze cycle. Researchers were not sure how the switch causes paralysis. The study demonstrates that photoswitches may have great potential in turning photodynamic treatment on and off, and for other applications in medicine and research, they indicate.........
Synthesis of hydrogen fuel storage material may become less complicated
This image illustrates that an applied electric field polarizes hydrogen molecules and the substrate, inducing hydrogen absorption with good thermodynamics and kinetics. Image courtesy of Qian Wang, Ph.D./VCU.
An international team of scientists has identified a new theoretical approach that may one day make the synthesis of hydrogen fuel storage materials less complicated and improve the thermodynamics and reversibility of the system.
A number of scientists have their sights set on hydrogen as an alternative energy source to fossil fuels such as oil, natural gas and coal that contain carbon, pollute the environment and contribute to global warming. Known to be the most abundant element in the universe, hydrogen is considered an ideal energy carrier - not to mention that it's clean, environmentally friendly and non-toxic. However, it has been difficult to find materials that can efficiently and safely store and release it with fast kinetics under ambient temperature and pressure.
The team of scientists from Virginia Commonwealth University ; Peking University in Beijing; and the Chinese Academy of Science in Shanghai; have developed a process using an electric field that can significantly improve how hydrogen fuel is stored and released.
"Eventhough tremendous efforts have been devoted to experimental and theoretical research in the past years, the biggest challenge is that all the existing methods do not meet the Department of Energy targets for hydrogen storage materials. The breakthrough can only be achieved by exploring new mechanisms and new principles for materials design," said Qiang Sun, Ph.D., research associate professor with the VCU team, who led the study.........
Transforming lead into gold is an impossible feat, but a similar type of "alchemy" is not only possible, but cost-effective too. Three Penn State scientists have shown that certain combinations of elemental atoms have electronic signatures that mimic the electronic signatures of other elements. As per the team's leader A. Welford Castleman Jr., Eberly Distinguished Chair in Science and Evan Pugh Professor in the Departments of Chemistry and Physics, "the findings could lead to much cheaper materials for widespread applications such as new sources of energy, methods of pollution abatement, and catalysts on which industrial nations depend heavily for chemical processing".
The scientists also showed that the atoms that have been identified so far in these mimicry events can be predicted simply by looking at the periodic table. The team used advanced experimentation and theory to quantify these new and unexpected findings. "We're getting a whole new perspective of the periodic table," said Castleman. The team's findings would be reported in the 28 December 2009 early on-line issue of the journal Proceedings of the National Academy of Sciences, and at a later date in the print edition of the journal.
Castleman and his team -- which includes Samuel Peppernick, a former Penn State graduate student who now is a postdoctoral researcher at the Pacific Northwest National Laboratory, and Dasitha Gunaratne, a Penn State graduate student -- used a technique, called photoelectron imaging spectroscopy, to examine similarities between titanium monoxide and nickel, zirconium monoxide and palladium, and tungsten carbide and platinum. "Photoelectron spectroscopy measures the energy it takes to remove electrons from various electronic states of atoms or molecules, while simultaneously capturing snapshots of these electron-detachment events with a digital camera," said Castleman. "The method allows us to determine the binding energies of the electrons and also to observe directly the nature of the orbitals in which the electrons resided before they were detached. We observed that the amount of energy mandatory to remove electrons from a titanium-monoxide molecule is the same as the amount of energy mandatory to remove electrons from a nickel atom. The same is true for the systems zirconium monoxide and palladium and tungsten carbide and platinum. The key is that all of the pairs are composed of isoelectronic species, which are atoms with the same electron configuration." Castleman noted that, in this case, the term isoelectronic refers to the number of electrons present in the outer shell of an atom or molecule.........
Two Kent State University professors are part of a team of scientists who recently uncovered a way to pack tetrahedra, considered to be the simplest shaped regular solids with its four triangular sides, more densely than ever before. Peter Palffy-Muhoray, professor of chemical physics and associate director of the Liquid Crystal Institute at Kent State, and Xiaoyu Zheng, assistant professor in Kent State's Department of Mathematical Sciences, along with four colleagues at the University of Michigan and one at Case Western Reserve University, have broken a world record for packing the most tetrahedra into a given volume.
Their findings will be featured in the Dec. 10 issue of Nature, one of the leading international scientific journals, in an article co-authored by the seven researchers. The article is titled "Disordered, quasicrystalline and crystalline phases of densely packed tetrahedra".
The scientists were able to obtain the highest packing fraction of 85.03, meaning tetrahedra fill 85.03 percent of the volume of the container. This shattered the prior record of 78.2 percent set by two Princeton University scientists in August 2009.
"The question of how best to pack shapes into a volume is an age-old question," Palffy-Muhoray said. "Johannes Kepler asked how to pack spheres in the early 1600s, and it was only recently proven in 2005 that the best way is to stack them like cannonballs. It is easy to understand how cubes can entirely fill space with no voids, but the packing problem is still unsolved for the simple tetrahedron. Though it's a simple object, it can't fill space like cubes, so we wondered how hard tetrahedra would pack when you squeezed them together".........
There is more to the snowflake than its ability to delight schoolchildren and snarl traffic.
The structure of the frosty flakes also fascinate ice chemists like Purdue University's Travis Knepp, a doctoral candidate in analytical chemistry who studies the basics of snowflake structure to gain more insight into the dynamics of ground-level, or "tropospheric," ozone depletion in the Arctic.
"A lot of chemistry occurs on ice surfaces," Knepp said. "By better understanding the physical structure of the snow crystal - how it grows and why it takes a certain shape - we can get a better idea of the chemistry that occurs on that surface."
His work on snowflake shape and how temperature and humidity affect it takes place in a special laboratory chamber no larger than a small refrigerator. Knepp can "grow" snow crystals year-round on a string inside this chamber. The chamber's temperature ranges from 100-110 degrees Fahrenheit down to minus 50 degrees Fahrenheit.
Knepp, under the direction of Paul Shepson, professor and head of Purdue's Department of Chemistry, is studying snow crystals and why sharp transitions in shape occur at different temperatures. The differences he sees not only explain why no two snowflakes are identical, but also hold implications for his ozone research in the Arctic Ocean region.........
Physicists have developed a new thermometry method suitable for measuring temperatures of ultracold atoms.
Credit: Illustration: Alan Stonebraker
As physicists strive to cool atoms down to ever more frigid temperatures, they face the daunting task of developing new, reliable ways of measuring these extreme lows. Now a team of physicists has devised a thermometer that can potentially measure temperatures as low as tens of trillionths of a degree above absolute zero. Their experiment is published in the current issue of Physical Review Letters and highlighted with a Viewpoint in the December 7 issue of Physics (http://physics.aps.org.).
Physicists can currently cool atoms to a few billionths of a degree, but even this is too hot for certain applications. For example, Richard Feynman dreamed of using ultracold atoms to simulate the complex quantum mechanical behavior of electrons in certain materials. This would require the atoms to be lowered to temperatures at least a hundred times colder than what has ever been achieved. Unfortunately, thermometers that can measure temperatures of a few billionths of a degree rely on physics that doesn't apply at these extremely low temperatures.
Now a team at the MIT-Harvard Center for Ultra-Cold Atoms has developed a thermometer that can work in this unprecedentedly cold regime. The trick is to place the system in a magnetic field, and then measure the atoms' average magnetization. By determining a handful of easily-measured properties, the physicists extracted the temperature of the system from the magnetization. While they demonstrated the method on atoms cooled to one billionth of a degree, they also showed that it should work for atoms hundreds of times cooler, meaning the thermometer will be an invaluable tool for physicists pushing the cold frontier.........
WHOI chemist Scott Doney led a team that developed ocean-model simulations for estimating the historical variations in air-sea CO2 fluxes. (Tom Kleindinst, Woods Hole Oceanographic Institution)
The annual rate of increase in carbon dioxide emissions from fossil fuels has more than tripled in this decade, in comparison to the 1990s, reports an international consortium of scientists, who paint a bleak picture of the Earth's future unless "CO2 emissions [are] drastically reduced".
These CO2 emissions increased at a rate of 3.4% per year from 2000 to 2008, in contrast to 1% each year in the prior decade, researchers from the Global Carbon Project report in the current issue of Nature Geoscience. The team comprises some 30 scientists from around the world, including Scott C. Doney, senior scientist at the Woods Hole Oceanographic Institution (WHOI) and Richard A. Houghton, senior scientist and acting director of the Woods Hole Research Center (WHRC).
Since 2000, the researchers documented an overall increase of 29% in global CO2 emissions. They attributed the rise to increasing production and trade of manufactured products, especially from emerging economies, the gradual shift from oil to coal and the planet's waning capacity to absorb CO2.
Doney led a team that developed ocean-model simulations for estimating the historical variations in air-sea CO2 fluxes.
"Over the last decade, CO2 emissions have continued to climb despite efforts to control emissions," Doney said. "Preliminary evidence suggests that the land and ocean appears to be becoming less effective at removing CO2 from the atmosphere, which could accelerate future climate change".........
This schematic shows the structure of the new material, Xe(H2)7. Freely rotating hydrogen molecules (red dumbbells) surround xenon atoms (yellow).
Credit: Nature Chemistry
Researchers at the Carnegie Institution have found for the first time that high pressure can be used to make a unique hydrogen-storage material. The discovery paves the way for an entirely new way to approach the hydrogen-storage problem. The scientists observed that the normally unreactive, noble gas xenon combines with molecular hydrogen (H2) under pressure to form a previously unknown solid with unusual bonding chemistry. The experiments are the first time these elements have been combined to form a stable compound. The discovery debuts a new family of materials, which could boost new hydrogen technologies. The paper is reported in the November 22, 2009, advanced online publication of Nature Chemistry
Xenon has some intriguing properties, including its use as an anesthesia, its ability to preserve biological tissues, and its employment in lighting. Xenon is a noble gas, which means that it does not typically react with other elements.
As main author Maddury Somayazulu, research scientist at Carnegie's Geophysical Laboratory, explained: "Elements change their configuration when placed under pressure, sort of like passengers readjusting themselves as the elevator becomes full. We subjected a series of gas mixtures of xenon in combination with hydrogen to high pressures in a diamond anvil cell. At about 41,000 times the pressure at sea level (1 atmosphere), the atoms became arranged in a lattice structure dominated by hydrogen, but interspersed with layers of loosely bonded xenon pairs. When we increased pressure, like tuning a radio, the distances between the xenon pairs changedthe distances contracted to those observed in dense metallic xenon".........
Is there an easy way to memorise all 112 elements? Yes, there is. You could make up a melody, and sing them. Melody is a great mnemonic device. The idea was used by Carleton...
Visualization of helium-4 and beryllium nuclei. Image: Peter Mueller (Argonne National Lab)
A recent experiment at the Department of Energy's Thomas Jefferson National Accelerator Facility has observed that a proton's nearest neighbors in the nucleus of the atom may modify the proton's internal structure.
When comparing large nuclei to small nuclei, past measurements have shown a clear difference in how the proton's constituent particles, called quarks, are distributed. This difference is called the EMC Effect.
A number of models of the EMC Effect predict that it is caused by the mass or density of the nucleus in which the proton resides. To test these predictions, experimenters made precise new measurements of the EMC effect in a variety of light nuclei, such as isotopes of helium.
"What we found is that there is a large modification of the quark structure in helium-4, and there was a much smaller effect in helium-3. And even though they were both light nuclei, they had a very different EMC Effect," said John Arrington, a spokesperson for the experiment and a nuclear physicist at DOE's Argonne National Lab.
The results, Arrington added, rules out the idea that the size of the EMC effect scales with the mass of the nucleus.
Next, the experimenters turned their attention to density. They compared the EMC Effect in beryllium to various other nuclei. Beryllium has a mass similar to carbon but a much lower density, roughly the same as helium-3. They observed that the size of the EMC Effect in beryllium is similar to that of carbon, which is twice as dense.........
Shane Stephens-Romero built a computer model called STREET that foresees the effects of alternative transportation fuels. Photo by Daniel A. Anderson / University Communications
It's the year 2060, and 75 percent of drivers in the Greater Los Angeles area have hydrogen fuel cell vehicles that emit only water vapor.
Look into Shane Stephens-Romero's crystal ball - a computer model called STREET - and find that air quality has significantly improved. Greenhouse gas emissions are more than 60 percent lower than in 2009, and levels of microscopic soot and ozone are about 15 percent and 10 percent lower, respectively.
"For the first time, we can look at these future fuel scenarios and say how they're going to impact things like ozone and particulate matter, which have severe effects on people's lungs and quality of life," said Stephens-Romero, a UC Irvine doctoral candidate in the Advanced Power & Energy Program.
His 2060 analysis appeared online recently in Environmental Science & Technology. It's the first peer-evaluated test of the computer model, which has caught the attention of California policymakers and auto industry leaders trying to integrate alternative fuels into the transportation system.
"We're transitioning to new technologies. How do we do this while maintaining our lifestyle and keeping our economy robust?" Stephens-Romero said. "We don't know how these changes could affect the future".
The Spatially & Temporally Resolved Energy & Environment Tool, he says, can help.........
An unusual "trigonal bipyramidal coordination" of manganese compounds was used to create a new blue pigment that is safe to produce, durable and environmentally benign.
An accidental discovery in a laboratory at Oregon State University has apparently solved a quest that over thousands of years has absorbed the energies of ancient Egyptians, the Han dynasty in China, Mayan cultures and more - the creation of a near-perfect blue pigment.
Through much of recorded human history, people around the world have sought inorganic compounds that could be used to paint things blue, often with limited success. Most had environmental or durability issues. Cobalt blue, developed in France in the early 1800s, can be carcinogenic. Prussian blue can release cyanide. Other blue pigments are not stable when exposed to heat or acidic conditions.
But chemists at OSU have discovered new compounds based on manganese that should address all of those concerns. They are safer to produce, much more durable, and should lead to more environmentally non-malignant blue pigments than any being used now or in the past. They can survive at extraordinarily high temperatures and don't fade after a week in an acid bath.
The findings were just reported in the Journal of the American Chemical Society, and a patent has been applied for on the composition of the compound and the process used to create it. The research was funded by the National Science Foundation.........
Pacific Northwest National Laboratory scientist David Heldebrant demonstrates how a new process called reversible acid gas capture works to pull more than just carbon dioxide out of power plant emissions.
The Department of Energy's Pacific Northwest National Laboratory has developed a reusable organic liquid that can pull harmful gases such as carbon dioxide or sulfur dioxide out of industrial emissions from power plants. The process could directly replace current methods and allow power plants to capture double the amount of harmful gases in a way that uses no water, less energy and saves money.
"Power plants could easily retrofit to use our process as a direct replacement for existing technology," said David Heldebrant, PNNL's lead research scientist for the project.
Harmful gases such as carbon dioxide or sulfur dioxide are called "acid gases". The new scrubbing process uses acid gas-binding organic liquids that contain no water and appear similar to oily compounds. These liquids capture the acid gases near room temperature. Researchers then heat the liquid to recover and dispose of the acid gases properly.
These recyclable liquids require much less energy to heat but can hold two times more harmful gases by weight than the current leading liquid absorbent used in power plants. It is a combination of water and monoethanolamine, a basic organic molecule that grabs the carbon dioxide.
PNNL's prior work with the all-organic liquids focused on pulling only carbon dioxide out of emissions from power plants. New work will show how the process can be applied to other acid gases such as sulfur dioxide.........
This formic acid-mediated deoxygenation reaction converts glycerol and other unwanted biomass byproducts into feedstocks for commodity chemicals. It could enable biomass to serve as a renewable replacement for petrochemicals.
Credit: Graphic courtesy of Elena Arceo
In revisiting a chemical reaction that's been in the literature for several decades and adding a new wrinkle of their own, scientists with Berkeley Lab and the University of California (UC) Berkeley have discovered a mild and relatively inexpensive procedure for removing oxygen from biomass. This procedure, if it can be effectively industrialized, could allow a number of of today's petrochemical products, including plastics, to instead be made from biomass.
"We've found and optimized a selective, one-pot deoxygenation technique based on a formic acid therapy," said Robert Bergman, a co-principal investigator on this project who holds a joint appointment with Berkeley Lab's Chemical Sciences Division and the UC Berkeley Chemistry Department.
The formic acid, Bergman said, converts glycerol, a major and unwanted by-product in the manufacturing of biodiesel, into allyl alcohol, which is used as a starting material in the manufacturing of polymers, drugs, organic compounds, herbicides, pesticides and other chemical products. Allyl alcohol today is produced from the oxidation of petroleum.
Said Jonathan Ellman, a UC Berkeley chemistry professor and the other principal investigator in this research, "Right now, about five percent of the world's supply of petroleum is used to make feedstocks that are synthesized into commodity chemicals. If these feedstocks can instead be made from biomass they become renewable and their production will no longer be a detriment to the environment".........
A 3-D model of the alkaloid serratezomine A shows the molecule's complex ring structure.
Credit: Johnston Group
The club moss Lycopodium serratum is a creeping, flowerless plant used in homeopathic medicine to treat a wide variety of ailments. It contains a potent brew of alkaloids that have attracted considerable scientific and medical interest. However, the plant makes a number of of these compounds in extremely low amounts, hindering efforts to test their therapeutic value.
That is no longer a problem for what is arguably the most complex of these alkaloids, a compound called Serratezomine A: an alkaloid that could have anti-cancer properties and may combat memory loss. A team of synthetic chemists at Vanderbilt University report in the March 18 issue of the Journal of the American Chemical Society that they have created an efficient way to make this molecule from scratch.
It took six years to develop the process because the scientists had to invent some entirely new chemical methods to complete the synthesis. These methods should make it easier to synthesize other Lycopodium alkaloids as well as other natural compounds with therapeutic potential.
In addition to their therapeutic possibilities, the Vanderbilt chemists were attracted to these compounds because they are among the most intricately structured and functionally dense of all the small molecules produced by living organisms. The compounds consist of carbon and nitrogen atoms assembled in unique ring structures.........
This graphic depicts the quantum mechanical principle of super-adiabaticity
In developing a model to explain the motion of atoms in a magnetic field, researchers have overcome a decades-old obstacle to understanding a key component of magnetic resonance.
The new understanding may eventually lead to better control of magnetic resonance imaging (MRI) and higher resolution MRI diagnoses.
Collaborators at Ohio State University in Columbus and three institutions in France--the Centre National de la Recherche Scientifique, the Universit d'Orlans, and the Universit de Lyon--presented their findings in a paper that appears early online Nov. 25, 2008, in the Journal of Chemical Physics
"This is very exciting work", said Tanja Pietra, the program officer at the National Science Foundation who partially supported this project. "The fact that the scientists did not set out to work on this problem but more or less stumbled upon it and then used their ingenuity to solve it, demonstrates the importance of conducting basic research. In this case, the work may have a major impact on magnetic resonance imaging, positively affecting a number of peoples' lives." .
The key breakthrough is a new understanding of a type of physical process called adiabaticity. Adiabatic processes are what physicists and engineers routinely use to control atoms in nuclear magnetic resonance (NMR) spectroscopy, and its better known sister, MRI.........
Laboratory scientists have posited an explanation for superconductivity that may open the door to the discovery of new, unconventional forms of superconductivity.
In a November 20 Nature letter, research led by Tuson Park and Joe D. Thompson describes a new explanation for superconductivity in non-traditional materials-one that describes a potentially new state of matter in which the superconducting material behaves simultaneously as a nonmagnetic material and a magnetic material.
Superconducting materials carry a current without resistance, commonly when cooled to temperatures nearing the liquid point of helium (nearly 452 degrees below zero Fahrenheit). Superconductors are extremely important materials because they hold promise for carrying electricity from one place to another without current loss or providing indefinite electric storage capacity. However, the cost of cooling materials to such extremely low temperatures currently limits the practicality of superconductors. If superconductors could be designed to operate at temperatures closer to room temperature, the results would be revolutionary.
Traditional theories of superconductivity hold that electrons within certain nonmagnetic materials can pair up when jostled together by atomic vibrations known as phonons. In other words, phonons provide the "glue" that makes superconductivity possible.........
Another step towards quantum computing was taken when a team of scientists processed information in the electron spin (blue) and stored it in the nuclear spin (yellow) of phosphorus atoms through a combination of microwave and radio-frequency pulses. (Image by Flavio Robles, Berkeley Lab Public Affairs)
Another step towards quantum computing - the Holy Grail of data processing and storage - was achieved when an international team of researchers that included scientists with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) were able to successfully store and retrieve information using the nucleus of an atom.
In a paper entitled: "Solid-state quantum memory using the 31P nuclear spin," reported in the October 23 issue of the journal Nature, the team described an experiment in which exceptionally pure and isotopically controlled crystals of silicon were precisely doped with phosphorus atoms. Quantum information was processed in phosphorus electrons, transferred to phosphorus nuclei, then subsequently transferred back to the electrons. This is the first demonstration that a single atomic nucleus can serve as quantum computational memory.
John Morton of Oxford University was the lead author. Co-authoring the paper from Berkeley Lab were Thomas Schenkel, Eugene Haller and Joel Ager. Other co-authors were Richard Brown, Brendon Lovett and Arzhang Ardavan of Oxford University, and Alexei Tyryshkin, Shyam Shankar and Stephen Lyon, of Princeton, University.
The immediate lure of quantum computing is blinding speed: a quantum computer would be able to perform certain mathematical tasks, such as factoring, a number of billions of times faster than the most powerful supercomputers of today. Beyond that, quantum computing should make it possible to engage calculations that cannot be considered with current "classical" computing technology. The secret behind quantum computing is the weird, counterintuitive but demonstrably real properties of quantum mechanics.........
NIST scientists found that gold and silver nanostars improved the sensitivity of Surface Enhanced Raman Spectroscopy 10 to 100,000 times that of other commonly used nanoparticles. These uniquely shaped nanoparticles may one day be used in a range of applications from disease diagnostics to contraband identification. Color added for clarity.
Credit: NIST
Novel nanoparticles being tested at the National Institute of Standards and Technology (NIST) have scientists seeing stars. In a recent paper,* NIST researchers used surface-enhanced Raman spectroscopy (SERS) to demonstrate that gold nanostars exhibit optical qualities that make them superior for chemical and biological sensing and imaging. These uniquely shaped nanoparticles may one day be used in a range of applications from disease diagnostics to contraband identification.
SERS relies on metallic nanoparticles, most usually gold and silver, to amplify signals from molecules present in only trace quantities. For these types of experiments, researchers shine laser light on an aqueous solution containing the nanoparticles and the molecule of interest and monitor the scattered light. The detailed characteristics of both the molecule and the nanoparticle affect the strength of scattered light, which contains an identifying fingerprint for the molecule known as its vibrational signature. With nanoparticles amplifying the signature, it is possible to detect a very low concentration of molecules in a solution.
The NIST team tested the optical properties of the nanostars using two target molecules, 2-mercaptopyridine and crystal violet. These molecules were selected because of their structural similarity to biological molecules and their large number of delocalized electrons, a characteristic that lends itself to SERS. NIST scientists observed that the Raman signal of 2-mercaptopyridine was 100,000 stronger when nanostars were present in the solution. The stars were also shown to be especially capable of enhancing the signature of crystal violet, delivering a signal about 10 times stronger than the prior winner, nanorods. Both the nanostars and the nanorods outperformed the nanospheres usually used for Raman enhancement.........
AAlbert Einstein once quipped, "Reality is merely an illusion, albeit a very persistent one." The famous scientist might have added that the illusion of reality shifts over time. As per a new Brandeis University study in the recent issue of Psychological Science, age influences how we perceive the future. When thinking about the future, some people seem pessimistic, while others' optimism seems to border on fantasy. Whether a person is naturally a pessimist or an optimist, the study suggests there are other factors at work in determining the way people consider how satisfying their future lives may be.
Brandeis University psychology expert Margie Lachman along with Christina Rcke, University of Zurich, Christopher Rosnick, Southern Illinois University, and Carol Ryff, University of Wisconsin, wanted to see if there were differences in actual and perceived ratings of how satisfied Americans were with their lives over a nine-year period. To test this idea, the scientists conducted two surveys, the first in 1995-1996, and the second nine years later, between 2004 and 2006.
In the first survey, participants (between the ages of 24-74) completed a telephone interview and questionnaire. They were asked to rate how currently satisfied they were with their lives, how satisfied they were with their lives 10 years earlier and how satisfied they expected to be 10 years later. In 2004, the participants were asked those same questions.........
The subject of 'gas bubbles in liquids' has a number of applications in industry. Examples include separating oil from water in the oil industry, how ink drops behave in printers and the manufacture of products in the food industry, such as mayonnaise. 'This subject of course also applies to natural processes such as rainfall and boiling water,' PhD student Jok Tang adds.
Experiments
Industry benefits from knowing how a current with bubbles behaves. This knowledge enables production processes to be improved. Until now, in spite of ever more powerful computers, it has proved difficult to calculate the behaviour of currents with bubbles properly. Computers mandatory too much time to solve the corresponding mathematical equations.
To gain insight into current behaviour, researchers generally conduct small-scale experiments. 'But,' Tang says, 'these experiments are expensive and difficult to perform.'.
Quick
'We think that our method will be adopted by industry in the not too distant future. Not just because the need for this method becomes greater when calculating larger-scale problems, but mainly because it is quicker and cheaper than the methods used now,' Tang explains.........
Physicists harness effects of disorder in magnetic sensors
University of Chicago physicist Thomas Rosenbaum, with the helium dilution refrigerator in his laboratory, where he observes the quantum behavior of materials chilled to temperatures approaching absolute zero.
Credit: Dan Dry
University of Chicago researchers have discovered how to make magnetic sensors capable of operating at the high temperatures that ceramic engines in cars and aircraft of the future will require.
The key to fabricating the sensors involves slightly degrading samples of a well-known semiconductor material, called indium antimonide, which is valued for its purity. Chicago's Thomas Rosenbaum and associate Jingshi Hu, now of the Massachusetts Institute of Technology, have published their formula in the recent issue of the journal Nature Materials
Most magnetic sensors operate by detecting how a magnetic field alters the path of an electron. Conventional sensors lose this capability when subjected to temperatures reaching hundreds of degrees. Not so in the indium antimonide magnetosensors that Rosenbaum and Hu developed with support from the U.S. Department of Energy.
"This sensor would be able to function in those sorts of temperatures without any degradation," said Rosenbaum, the John T. Wilson Distinguished Service Professor in Physics.
Rosenbaum's research typically focuses on the properties of materials observed at the atomic level when subjected to temperatures near absolute zero (minus-460 degrees Fahrenheit). More than a decade ago, he led a team of researchers in experiments involving silver selenide and silver telluride, two materials that exhibited no magnetic response at low temperatures. But when the team introduced a tiny amount of silver (one part in 10,000) to the materials, their magnetic response skyrocketed.........
Iowa State University researcher Robert Jernigan believes that his research shows proteins have controlled motions.
Most biochemists traditionally believe proteins have a number of random, uncontrolled movements.
Research conducted by Jernigan, director of the L.H. Baker Center for Bioinformatics and Biological Statistics together with Guang Song, an assistant professor in computer science and graduate student Lei Yang, over a 10-year period shows that not only are protein motions more restricted, but also that these restricted, controlled motions are part of the function of the proteins.
The group's findings were recently reported in the journal "Structure".
Using as an example a protein from HIV virus, Jernigan conducted his research using a simple model and tested to see how the proteins moved. The large number of reported structures show exactly the motions that are mandatory for their function, and exactly the same motions as computed by Jernigan's model.
"This is one experimental case that is indicative, but there are a number of others," he said.
Jernigan believes this research is the first step to better understanding proteins and cell behaviors.
"There is the possibility of creating designer drugs with this newly discovered information," he said.........
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