Thursday, May 19, 2011

Molecular researchers discover novel gene linked to aging hearts

Researchers at the University of Ottawa Heart Institute (UOHI) have identified a novel gene in the nucleus of muscle and brain cells that affects heart development and the aging process. Their investigation brings the promise of new treatments for an old, failing heart.

"We know that aging is the greatest predictor of and . So we have been working backward in time, looking at the fetal heart to understand changes in the process as it ages, grows frail and fails," said molecular biologist Patrick Burgon, PhD.

A research team led by Burgon discovered the gene in the cell's nucleus – the site where hereditary information or DNA is housed – suggesting that it may control the behavior of other genes important in .

The researchers, who focus on the fetal heart as it grows into an adult heart, named the gene MLIP for Muscle enriched A-type Lamin Interacting Protein. Mutations in the Lamin gene family are associated with muscular dystrophy and other degenerative heart muscle diseases.

Their findings have been reported electronically in the Journal of Biological Chemistry and are scheduled for formal publication in June. Researchers now will investigate how animal models respond when the MLIP gene is removed to gain greater knowledge into its function.

"Greater knowledge of this gene and how it works will help us understand loss of cardiac function. Our research opens up new avenues relevant to the characteristics of cardiac development," said Burgon.

At the Heart Institute, studies to identify complex cardiovascular mechanisms are part of a world-wide effort among a core of leading scientific organizations. The Heart Institute collaborates with an international consortium that has already discovered 13 new genes that increase the risk of coronary artery disease (CAD).

Heart Institute researchers previously identified gene 9p21 – the first genetic risk factor recognized for disease and the first major new cardiovascular risk factor since the discovery of cholesterol. The Institute has also located a variety of other genes influencing diseases such as atrial fibrillation and biological processes such as obesity.

More information:

Provided by University of Ottawa Heart Institute

Diminutive 3-D printers to enable home manufacturing of custom objects

A research project at the Vienna University of Technology (TU Vienna) could turn futuristic 3-D printers into affordable everyday items. Printers, which can produce three-dimensional objects have been available for years. However, at the Vienna University of Technology, a printing device has now been developed, which is much smaller, lighter and cheaper than ordinary 3-D printers. With this kind of printer, everyone could produce small, tailor-made 3-D objects at home, using building plans from the internet -- and this could save money for expensive custom-built spare parts.

Several scientific fields have to come together, to design a 3-D printer. The device was assembled by mechanical engineers in the research group of professor Jürgen Stampfl, but also the chemical research by the team of professor Robert Liska was of crucial importance: first, chemists have to determine which special kinds of synthetic material can be used for printing.

Layer for Layer

The basic principle of the 3-D printer is quite simple: The desired object is printed in a small tub filled with synthetic resin. The resin has a very special property: It hardens precisely where it is illuminated with intense beams of light. Layer for layer, the synthetic resin is irradiated at exactly the right spots. When one layer hardens, the next layer can be attached to it, until the object is completed. This method is called "additive manufacturing technology." "This way, we can even produce complicated geometrical objects with an intricate inner structure, which could never be made using casting techniques," Klaus Stadlmann explains. He developed the prototype together with Markus Hatzenbichler.

This method is not designed for large-scale production of bulk articles -- for that, there are cheaper alternatives. The great advantage of additive manufacturing is the fact that is offers the possibility to produce tailor-made, individually adjusted items. The prototype of the printer is no bigger than a carton of milk, it weighs 1.5 kilograms, and at just 1200 Euros, it was remarkably cheap. "We will continue to reduce the size of the printer, and the price will definitely decrease too, if it is produced in large quantities," Klaus Stadlmann believes.

LED-Projector for Higher Resolution

The printer's resolution is excellent: The individual layers hardened by the light beams are just a twentieth of a millimetre thick. Therefore, the printer can be used for applications which require extraordinary precision -- such as construction parts for hearing aids. Unlike previous models, the printer at TU Vienna uses light emitting diodes, with which high intensities of light can be obtained at very well-defined positions.

The research group for additive manufacturing technologies at TU Vienna is working with a variety of different 3-D techniques and materials. New materials -- such as special ceramics or polymers -- are constantly being developed for 3-D printing. 3-D objects can now even be made from eco-friendly biodegradable substances. In cooperation with biologists and physicians, the scientists could show that the artificial structures created with their 3-D printer technology are perfectly suited to serve as a scaffold that supports natural growth of bone structure in the body.

Remarkable Versatility

No matter whether it is medical parts, adjusted exactly to the patient's needs, special spare parts which otherwise would have to be shipped around half the globe, or whether it is just some kind of self-designed bling jewelery: with the versatile and cheap devices and materials developed in Vienna, highly complex 3-D objects can now be built from a variety of materials with very different mechanical, optical and thermal properties.

Story Source:

The above story is reprinted (with editorial adaptations ) from materials provided by Vienna University of Technology, TU Vienna.

Reality of 'supersolid' in helium-4 challenged

The long-held, but unproven idea that helium-4 enters into an exotic phase of matter dubbed a "supersolid" when cooled to extremely low temperatures has been challenged in a new paper published recently in Science.

Los Alamos National Laboratory researchers Alexander Balatsky and Matthias Graf joined Cornell University physicist J.C. Séamus Davis and others in describing an alternative explanation for behavior of helium-4 that led scientist to believe for nearly 40 years that the substance could hold properties of a liquid and solid at the same time when cooled to near Absolute Zero.

Helium-4 is the same gas used to fill carnival balloons. When cooled to temperatures below minus 452 degrees below zero Fahrenheit, helium-4 becomes a liquid -- and an extraordinary liquid at that. At very low temperatures, helium-4 can become a "superfluid," a liquid without viscosity that can flow unhampered by friction.

When placed under pressure at these low temperatures, helium-4 atoms arrange in an orderly lattice, or solid, which physicists nearly 40 years ago believed could behave in a similarly frictionless manner as a supersolid -- a unique theoretical state of matter in which a bulk lattice of material could move as a single frictionless object.

Physicists came to the idea that helium-4 becomes a supersolid after oscillating liquid helium-4 back and forth in a special apparatus that measured the rotational speed. When the researchers measured these motions under conditions that would induce a solid form of helium-4, they noticed that the oscillation speed increased slightly, as if some part of the mass had come loose and was uninhibited by interaction with the rest of material. This effect was interpreted as evidence of supersolidity, a phase in which some of the mass of a solid does not move with the rest of solid lattice, but rather flows freely through the lattice.

Los Alamos researchers Balatsky and Graf posited that the effect could be described by an entirely different explanation. They believed the change in oscillation speed could have arisen as the result of a gradual "freezing out" of imperfections within the helium-4 lattice. To illustrate on a very basic level, Balatsky uses a rotating egg.

A fresh egg is a mixture of yolk and albumen within a shell. When spun, the interaction of the liquid within the eggshell results in a relatively slow rotation. If the egg is frozen, however, the imperfections within the shell freeze out, and the egg spins much faster -- like the increase in oscillation speed observed in the early torsional oscillation experiments.

To test this simplified analogy, Balatsky, Davis and colleagues devised an experiment using a torsional oscillator that was 10,000 times more sensitive than the ones used in previous experiments. The researchers looked at results of varying temperature at a constant oscillation speed versus results of varying oscillation speeds at constant temperature. They compared the microscopic excitations within solid helium-4 under both conditions and found that the plotted curves were nearly identical.

Perhaps more significantly, the researchers didn't see a sudden, clearly demarked change in the relaxation of microscopic defects at some "critical temperature" during their experiments. Lack of such a sharp demarcation provides evidence against a change in phase of helium-4 to a supersolid.

Instead, it suggests that the earlier observed behavior was the result of everyday physics rather than some exotic behavior.

"While this experiment does not definitively rule out the possibility of the formation of a supersolid in helium-4, the fact that we have provided a reasonable alternative explanation for the observed behavior in earlier experiments weakens the argument that what was being seen was a phase change to a supersolid," Balatsky said.

In addition to Los Alamos researchers Balatsky and Graf, and Cornell physicist Davis, co-authors of the paper include: Ethan Pratt, formerly of Cornell, but now at the National Institute of Standards and Technology; Ben Hunt and graduate student Vikram Gadagkar at the Massachusetts Institute of Technology; and Minoru Yamashita at Kyoto University.

Story Source:

The above story is reprinted (with editorial adaptations ) from materials provided by DOE/Los Alamos National Laboratory.

Journal Reference:

E. J. Pratt, B. Hunt, V. Gadagkar, M. Yamashita, M. J. Graf, A. V. Balatsky, and J. C. Davis. Interplay of Rotational, Relaxational, and Shear Dynamics in Solid 4He. Science, 13 May 2011: Vol. 332 no. 6031 pp. 821-824 DOI: 10.1126/science.1203080

Diamond aerogel: New form of diamond is lighter than ever

ScienceDaily (May 17, 2011) — By combining high pressure with high temperature, Livermore researchers have created a nanocyrstalline diamond aerogel that could improve the optics for something as big as a telescope or as small as the lenses in eyeglasses.

Aerogels are a class of materials that exhibit the lowest density, thermal conductivity, refractive index and sound velocity of any bulk solid. Aerogels are among the most versatile materials available for technical applications due to their many exceptional properties. This material has chemists, physicists, astronomers, and materials scientists utilizing its properties in myriad applications, from a water purifier for desalinizing seawater to installation on a NASA satellite as a meteorite particle collector.

In new research appearing in the May 9-13 online edition of the Proceedings of the National Academy of Sciences, a Livermore team created a diamond aerogel from a standard carbon-based aerogel precursor using a laser-heated diamond anvil cell.

A diamond anvil cell consists of two opposing diamonds with the sample compressed between them. It can compress a small piece of material (tens of micrometers or smaller) to extreme pressures, which can exceed 3 million atmospheres. The device has been used to recreate the pressure existing deep inside planets, creating materials and phases not observed under normal conditions. Since diamonds are transparent, intense laser light also can be focused onto the sample to simultaneously heat it to thousands of degrees.

The new form of diamond has a very low density similar to that of the precursor of around 40 milligrams per cubic centimeter, which is only about 40 times denser than air.

The diamond aerogel could have applications in antireflection coatings, a type of optical coating applied to the surface of lenses and other optical devices to reduce reflection. Less light is lost, improving the efficiency of the system. It can be applied to telescopes, binoculars, eyeglasses or any other device that may require reflection reduction. It also has potential applications in enhanced or modified biocompatibility, chemical doping, thermal conduction and electrical field emission.

In creating diamond aergoels, lead researcher Peter Pauzauskie, a former Lawrence fellow now at the University of Washington, infused the pores of a standard, carbon-based aerogel with neon, preventing the entire aerogel from collapsing on itself.

At that point, the team subjected the aerogel sample to tremendous pressures and temperatures (above 200,000 atmospheres and in excess of 2,240 degrees Fahrenheit), forcing the carbon atoms within to shift their arrangement and create crystalline diamonds.

The success of this work also leads the team to speculate that additional novel forms of diamond may be obtained by exposing appropriate precursors to the right combination of high pressure and temperature.

Livermore researchers on the project include: Jonathan Crowhurst, Marcus Worsley, Ted Laurence, Yinmin "Morris" Wang, Trevor Wiley, Kenneth Visbeck, William Evans, Joseph Zaug and Joe Satcher Jr.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by DOE/Lawrence Livermore National Laboratory.

Journal Reference:

P. J. Pauzauskie, J. C. Crowhurst, M. A. Worsley, T. A. Laurence, A. L. D. Kilcoyne, Y. Wang, T. M. Willey, K. S. Visbeck, S. C. Fakra, W. J. Evans, J. M. Zaug, J. H. Satcher. Synthesis and characterization of a nanocrystalline diamond aerogel. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1010600108

Note: If no author is given, the source is cited instead.

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