June 16, 2009, 9:42 PM CT

Extreme makeover chemistry style

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"......... Posted by: Sarah      Read more         Source

April 16, 2009, 5:05 AM CT

Chemists synthesize herbal alkaloid

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......... Posted by: Sarah      Read more         Source

November 27, 2008, 5:23 AM CT

Dancing atoms now understood

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......... Posted by: Sarah      Read more         Source

November 21, 2008, 8:35 PM CT

New Mechanism for Superconductivity

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......... Posted by: Sarah      Read more         Source

October 23, 2008, 8:49 PM CT

Scientists Store and Retrieve Data Inside an Atom

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......... Posted by: Kevin      Read more         Source

October 15, 2008, 5:19 PM CT

Gold nanostars outshine the competition

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......... Posted by: Sarah      Read more         Source

September 11, 2008, 9:15 PM CT

As good as it gets?

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......... Posted by: Sarah      Read more         Source

September 10, 2008, 8:50 PM CT

Maths aids mayonnaise production

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......... Posted by: Sarah      Read more         Source

September 9, 2008, 9:20 PM CT

Physicists harness effects of disorder in magnetic sensors

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......... Posted by: Sarah      Read more         Source

August 27, 2008, 6:44 PM CT

Proteins Have Controlled Motions

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......... Posted by: Sarah      Read more         Source

Tue, 26 Aug 2008 01:57:05 GMT

The Periodic Table Of Videos

Tables charting the chemical elements have been around since the 19th century - but this modern version has a short video about each one.

The Periodic Table Of Videos is an experiment by Professor Martyn Poliakoff of the University of Nottingham, UK. Posted by: Gerard      Read more     Source

August 20, 2008, 6:32 PM CT

Creating unconventional metals

The semiconductor silicon and the ferromagnet iron are the basis for much of mankind's technology, used in everything from computers to electric motors. In this week's issue of the journal Nature (August 21st) an international group of scientists, including academic and industrial scientists from the UK, USA and Lesotho, report that they have combined these elements with a small amount of another common metal, manganese, to create a new material which is neither a magnet nor an ordinary semiconductor. The paper goes on to show how a small magnetic field can be used to switch ordinary semiconducting behaviour (such as that seen in the electronic-grade silicon which is used to make transistors) back on.

The new material exists in a quantum halfway house between magnet and semiconductor - in the same way that much more complex materials such as ceramics which exhibit high temperature superconductivity exist in quantum halfway houses between metals and magnetic insulators. The research is of fundamental importance because it demonstrates, for the first time, a simple recipe for reaching this halfway house, whilst also suggesting new mechanisms for controlling electrical currents and magnetism in semiconductor devices.

Professor J.F. DiTusa of Louisiana State University and a co-author of the paper said: "It's amazing that something which was thought to exist theoretically in mathematical physics could actually be found in an alloy which was simply formed by melting together a few common elements"......... Posted by: Sarah      Read more         Source

July 3, 2008, 9:23 PM CT

Radicals Shake Up Molecules

Until now, it was usually thought that colliding molecules get the shakes as the result of energy transfer solely from the smashing of the molecules, but some new research adds a second means by which colliding molecules become vibrationally excited--it is being called the "Tug o' War Mechanism".

The new experiment, transforming the textbook story, waccording toformed in the lab of Richard Zare, chair of the Department of Chemistry at Stanford University. This work on energy transferring, or inelastic, collisions is featured in the July 3, 2008 issue of the journal Nature.

"How energy transfer occurs in molecular collisions is a topic of deep interest to chemists, for energy transfer is often the precursor to chemical transformations," Zare said. "This is the reason why I regard finding a new mechanism for energizing molecules through collisions to be of such potential importance".

"The work by Zare and colleagues shows an interesting and unexpected result," shared Charles Pibel, director of the Physical Chemistry Program at the National Science Foundation (NSF). "The conventional wisdom had been that most collisions between molecules excite vibrational motion through a hard impact, like a piano's hammer striking a string."

But instead of molecules impacting and deflecting backwards, the Tug o' War Mechanism stretches the molecule and then releases it, starting the molecule rattling. The effect is "more like a violinist, plucking a string, pizzicato." In the collisions studied by the Zare group, a lone hydrogen atom tugs on one end of a deuterium molecule and lets go, exciting the molecular deuterium into vibration......... Posted by: Sarah      Read more         Source

June 30, 2008, 6:47 PM CT

Physicists create millimeter-sized 'Bohr atom'

HOUSTON -- June 30, 2008 -- Nearly a century after Danish physicist Niels Bohr offered his planet-like model of the hydrogen atom, a Rice University-led team of physicists has created giant, millimeter-sized atoms that resemble it more closely than any other experimental realization yet achieved.

The research is available online in Physical Review Letters

Bohr offered the first successful theoretical model of the atom in 1913, suggesting that electrons traveled in orbits around the atom's nucleus like planets orbiting a star. Bohr's model led to a deeper understanding of both the chemical and optical properties of atoms and won him a Nobel Prize in 1922. But his notion of electrons traveling in discrete orbits was eventually displaced by quantum mechanics, which revealed that electrons don't have precise positions but are instead distributed in wave-like patterns.

"In a sufficiently large system, the quantum effects at the atomic scale can transition into the classical mechanics found in Bohr's model," said lead researcher Barry Dunning, Rice's Sam and Helen Worden Professor of Physics and Astronomy. "Using highly excited Rydberg atoms and a series of pulsed electric fields, we were able to manipulate the electron motion and create circular, planet-like states"......... Posted by: Sarah      Read more         Source

June 26, 2008, 8:43 PM CT

Quantum computing breakthrough

The odd behavior of a molecule in an experimental silicon computer chip has led to a discovery that opens the door to quantum computing in semiconductors.

In a Nature Physics journal paper currently online, the scientists describe how they have created a new, hybrid molecule in which its quantum state can be intentionally manipulated - a mandatory step in the building of quantum computers.

"Up to now large-scale quantum computing has been a dream," says Gerhard Klimeck, professor of electrical and computer engineering at Purdue University and associate director for technology for the national Network for Computational Nanotechnology.

"This development may not bring us a quantum computer 10 years faster, but our dreams about these machines are now more realistic".

The workings of traditional computers haven't changed since they were room-sized behemoths 50 years ago; they still use bits of information, 1s and 0s, to store and process information. Quantum computers would harness the strange behaviors found in quantum physics to create computers that would carry information using quantum bits, or qubits. Computers would be able to process exponentially more information.

If a traditional computer were given the task of looking up a person's phone number in a telephone book, it would look at each name in order until it found the right number. Computers can do this much faster than people, but it is still a sequential task. A quantum computer, however, could look at all of the names in the telephone book simultaneously......... Posted by: Kevin      Read more         Source

June 26, 2008, 8:22 PM CT

Much-Anticipated Online Mathematics Reference

The National Institute of Standards and Technology (NIST) has released a five-chapter preview of the much-anticipated online Digital Library of Mathematical Functions (DLMF). In development for over a decade, the DLMF is designed to be a modern successor to the 1964 "Handbook of Mathematical Functions," a reference work that is the most widely distributed NIST publication (with over a million copies in print) and one of the most cited works in the mathematical literature (still receiving over 1,600 yearly citations in the research literature). The preview of the new DLMF is a fully functional beta-level release of five of the 36 chapters.

The DLMF is designed to be the definitive reference work on the special functions of applied mathematics. Special functions are "special" because they occur very frequently in mathematical modeling of physical phenomena, from atomic physics to optics and water waves. These functions have also found applications in many other areas; for example, cryptography and signal analysis. The DLMF provides basic information needed to use these functions in practice, such as their precise definitions, alternate ways to represent them mathematically, illustrations of how the functions behave with extreme values and relationships between functions......... Posted by: Sarah      Read more         Source

June 10, 2008, 8:15 PM CT

Lost Reds In Homer Painting

More than 30 years ago, when Northwestern University chemist Richard Van Duyne developed a powerful new sensing technique, he never thought he would be using it to learn more about treasures in the Art Institute of Chicago's collection -- including a watercolor recently featured in the museum's exhibition "Watercolors by Winslow Homer: The Color of Light".

In Homer's watercolor "For to be a Farmer's Boy," painted in 1887, some of the red and yellow pigments have faded in the sky, leaving that area virtually without color. Van Duyne, Charles E. and Emma H. Morrison Professor of Chemistry in the Weinberg College of Arts and Sciences, is working with Francesca Casadio, a conservation scientist at the Art Institute, to determine what the original colors were.

To solve this mystery, they are using surface enhanced Raman spectroscopy (SERS), the analytical technique pioneered by Van Duyne in 1977. SERS uses laser light and nanoparticles of precious metals to interact with molecules to show the chemical make-up of a particular dye.

SERS is a variation of Raman spectroscopy, a widely used technique first developed in the 1920s. What sets SERS apart is its ability to analyze extremely minute samples of organic dyes; some samples are so small they cannot be seen by the naked eye......... Posted by: Sarah      Read more         Source

June 4, 2008, 10:49 PM CT

Prototype Hydrogen Storage Tank

A cryogenic pressure vessel developed and installed in an experimental hybrid vehicle by a Lawrence Livermore National Laboratory research team can hold liquid hydrogen for six days without venting any of the fuel.

Unlike conventional liquid hydrogen (LH2 tanks in prototype cars, the LLNL pressure vessel was parked for six days without venting evaporated hydrogen vapor.

The LLNL development has significantly increased the amount of time it takes to start releasing hydrogen during periods of long-term parking, as in comparison to today's liquid hydrogen tanks capable of holding hydrogen for merely two to four days.

LH2 tanks hold super-cold liquid hydrogen at around -420 Fahrenheit. Like water boiling in a tea kettle, pressure builds as heat from the environment warms the hydrogen inside. Current automotive LH2 tanks must vent evaporated hydrogen vapor after being parked three to four days, even when using the best thermal insulation available (200 times less conductive than Styrofoam insulation).

In recent testing of its prototype hydrogen tank onboard a liquid hydrogen (LH2) powered hybrid, LLNL's tank demonstrated a thermal endurance of six days and the potential for as much as 15 days, helping resolve a key challenge facing LH2 automobiles......... Posted by: Sarah      Read more         Source

May 20, 2008, 9:56 PM CT

New process could cause titanium price to tumble

Whether for stopping cars or bullets, titanium is the material of choice, but it has always been too expensive for all but the most specialized applications.

That could change, however, with a non-melt consolidation process being developed by Oak Ridge National Laboratory and industry partners. The new processing technique could reduce the amount of energy mandatory and the cost to make titanium parts from powders by up to 50 percent, making it feasible to use titanium alloys for brake rotors, artificial joint replacements and, of significant interest now, armor for military vehicles.

"We recently exhibited the new low-cost titanium alloy door made by ORNL for the Joint Light Tactical Vehicle, which is a next-generation combat vehicle," said Bill Peter, a researcher in ORNL's Materials Science and Technology Division. "By using a titanium alloy for the door, BAE Systems was able to reduce the weight of its vehicle yet at the same time decrease the threat of armor-piercing rounds."

The lightweight titanium alloy also improves the operation of the door and increases mobility of the vehicle, making it even more useful to the military.

Peter noted that the non-melt approach, which includes roll compaction for directly fabricating sheets from powder, press and sinter techniques to produce net shape components and extrusion, offers a number of advantages over traditional melt processing......... Posted by: Sarah      Read more         Source

May 18, 2008, 9:57 PM CT

Improved Ion Mobility Is Key to New Hydrogen Storage Compound

A materials scientist at the National Institute of Standards and Technology (NIST) has deciphered the structure of a new class of materials that can store relatively large quantities of hydrogen within its crystal structure for later release. The new analysis* may point to a practical hydrogen storage material for automobile fuel cells and similar applications.

The abundant element hydrogen could play a role in replacing carbon-based fuels for transportation in the future, but scientists first must develop a method to store and release large amounts of the highly flammable, odorless invisible gas economically and safely. There are materials that are known to trap relatively large quantities of hydrogen, at normal pressures, but to date they all require heating to fairly high temperatures to release the hydrogen.

Hui Wu, a research associate from the University of Maryland working in a cooperative research program at the NIST Center for Neutron Research, has been investigating a new hydrogen storage compound that mixes lithium amide with lightweight metal hydrides. Lithium amide can hold more than 10 percent of hydrogen by weight, well above the 6 percent target set by the U.S. Department of Energy as a 2010 goal for a hydrogen storage material for transportation. The material absorbs and releases hydrogen reversibly, but both absorbing and releasing the hydrogen requires high temperatures and also produces a toxic byproduct, ammonia......... Posted by: Sarah      Read more         Source