Saturday, March 12, 2011

Australian honey proves to be a powerful anti-bacterial treatment

Honey sourced from an Australian native myrtle tree has been found to have the most powerful anti-bacterial properties of any honey in the world and could be used to treat antibiotic-resistant bacterial infections that commonly occur in hospitals and nursing homes.

A Brisbane-based research group found that Australian native myrtle has very high levels of the anti-bacterial compound, Methylglyoxal (MGO), and outperforms all medicinal honeys currently available on the market, including Manuka honeys.

Led by the Queensland Alliance for Agriculture and Food Innovation (QAAFI), which is a partnership between The University of Queensland and the Queensland Government's Department of Employment, Economic Development and Innovation (DEEDI), the research is being carried out in conjunction with The Australian Organic Honey Company & Medi Bioactive Australia.

The project to date has involved comprehensive trials with honey harvested from a native species of myrtle (leptospermum polygalifolium), which is distributed along the Australian eastern seaboard from the south coast of NSW to Cape York.

CEO of The Australian Organic Honey Company & Medi Bioactive Australia, Carolyn MacGill, said the findings had shown anti-bacterial potency levels that could allow for the development of highly effective anti-bacterial treatments.

“We have had MGO readings in excess of 1750 mg/kg in certain batches of honey. This would make this range of honeys one of the most potent in the world,” Ms MacGill said.

Honeys investigated by the research group were effective as anti-bacterial treatments when used in the range of 500 – 1750 mg/kg MGO to prevent the growth of Methicillin-Resistant staphylococcus aureus (MRSA), a common bacterial infection in hospitals and community facilities where residents are immune challenged, such as .

Chief researcher working on the project, QAAFI scientist Dr Yasmina Sultanbawa, said the potency of the honeys meant that only a small amount was required to fight infection.

“The sheer strength, due to high levels of active compounds in these honeys, has meant that we have been able to completely inhibit MRSA for example in in-vitro studies with a relatively small quantity of the honey,” Dr Sultanbawa said.

“This means potential products could maintain significant levels of anti-bacterial activity even in surface wounds where the honey is diluted in the bed of the infection.

“The presence of MRSA in a wound is a matter of concern and MRSA-colonised wounds are an increasingly urgent problem in hospitals and nursing homes. The continued emergence of strains with resistance to antibiotics or even antiseptics adds to the difficulties of treating these infections.

“Investigations into unconventional remedies that are non-toxic and unlikely to result in resistance to the treatment, such as the QAAFI research into bioactive honeys, is very promising.”

According to Ms MacGill, the potential of the honeys could ultimately result in a range of highly sought-after products.

“Our research to date has produced overwhelming results in the quest to inhibit the very common infection MRSA at very low percentage rates of application,” Ms MacGill said.

“This could provide enormous benefits for Australian and international medical fraternities and their patients.”

Provided by University of Queensland (news : web)

Hair dyeing poised for first major transformation in 150 years

Technological progress may be fast-paced in many fields, but one mundane area has been almost left in the doldrums for the last 150 years: The basic technology for permanently coloring hair. That's the conclusion of an analysis of almost 500 articles and patents on the chemistry of permanent hair dyeing, which foresees much more innovation in the years ahead, including longer lasting, more-natural-looking dyes and gene therapy to reverse the gray. The article appears in ACS's journal Chemical Reviews.

Robert Christie and Olivier Morel note that hair dye already is a multibillion dollar international industry, poised for even greater expansion in the future due to the graying of a global population yearning to cling to appearances of youth. Most permanent hair coloring technology, however, is based on a 150-year-old approach that uses p-phenylenediamine (PPD), a chemical that produces darker, browner shades when exposed to air. Concern over the safety of PPD and other hair dye ingredients, and demand for more convenient hair dyeing methods, has fostered an upswing in research on new dyes and alternative hair coloring technologies.

The scientists describe progress toward those goals. Future hair coloring techniques include nano-sized colorants, for instance. Composed of 1/5,000th the width of a human hair, they will penetrate the hair and remain trapped inside for longer-lasting hair coloration. Scientists also are developing substances that stimulate the genes to produce the melanin pigment that colors hair. These substances promise to produce a wider range of more natural-looking colors, from blond to dark brown and black, with less likelihood of raising concerns about toxicity and better prospects for more natural results. Other new technologies may stop graying of the hair or prevent its formation altogether, the scientists say.

More information: "Current Trends in the Chemistry of Permanent Hair Dyeing" Chemical Reviews.

Provided by American Chemical Society (news : web)

Why many historians no longer see alchemy as an occult practice

 lchemy is making a comeback. No, wizards have not learned how to transmute lead into gold and they haven't found any rejuvenating elixir of life. But the scholars who write the history of science and technology no longer lump alchemy in with witchcraft as a pseudo-science.Instead they see alchemy as the proper precursor to modern chemistry. The modern word "alchemy" comes from the Arabic word "al kemia," which incorporated a spectrum of knowledge of chemical properties and practices from ancient times. Chemist and historian Lawrence Principe of Johns Hopkins University in Maryland believes that the hardworking alchemists of the late Middle Ages and the Renaissance, a period stretching across the 14th to the 17th centuries, were defamed by being lumped in with charlatans of the 19th century, quacks that were often depicted wearing eccentric costumes and casting spells. "We're in an alchemical revolution," said Principe during a meeting of the American Association for the Advancement of Science in February. Principe said that just in the past 30 years articles about alchemy were being accepted into Isis, one of the leading journals devoted to the history of science. Before that a prohibition on alchemical subjects had been in place.The reason for this change is that historians are now recognizing the huge role alchemists had in producing valuable things, even if the alchemists never succeeded in turning lead into gold. By the way, making new gold was of great concern to kings since it would have interfered with the valuation of coins. This is why transmutation was considered a crime and why alchemists often had to do their research in secret. Alchemists did something more important than make new gold. They were instrumental in the development of many technologies during pre-modern times in Europe. For example, alchemists could be considered as an early form of industrial researcher. William Newman of the University of Indiana points out that alchemists "integrated a host of pursuits that can be loosely labeled 'chemical technologies' with an experimental practice that was linked to various theories about the nature and operations of minerals and metals."Newman provides plenty of examples. Alchemists, he says, were active in assaying metals, refining salts, making dyes and pigments, making glass and ceramics, artificial fertilizers, perfumes, and cosmetics. An alchemists' shop was often the place in a town where you would go for medicine. Even today in many parts of Europe you go to "the chemist," for medicine, rather than to a "drug store."Principe said that alchemists perfected the process of distillation, in which a mixed substance is boiled in such a way as to separate out one component by letting a vapor collect in a portion of the apparatus where it can be drawn off. Distillation is of course well known as the means of making spirits like whiskey. But it was also used by alchemists to make powerful acids, which in turn were important for a variety of industrial purposes, such as for separating metals from their ores. The career of Robert Boyle illustrates the new, more respectful, view of alchemy. Boyle was long considered to be the first major modern chemist, one whose quantitative and careful laboratory practice made him the supposed antithesis of alchemy. But some 17th century documents, fully interpreted by Principe for the first time, show that Boyle was an avid alchemy practitioner. So was the man often cited as the father of modern physics, Isaac Newton. Provided by Inside Science News Service (news : web)Move the slider to adjust rank threshold, so that you can hide some of the comments.

Creasing to cratering: Voltage breaks down plastic (w/ Video)


A Duke University team has seen for the first time how soft polymers, such as wire insulation, can break down under exposure to electrical current.

Researchers have known for decades that polymers, such those insulating wires, may break down due to deformation of the polymers. But the process had never been seen.

In a series of experiments, Duke University engineers have documented at the microscopic level how plastic deforms to breakdown as it is subjected to ever-increasing electric voltage. Polymers can be found almost everywhere, most commonly as an for electrical wires, cables and capacitors.

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The findings by the Duke engineers could help in developing to improve the durability and efficiency of any polymer that must come into contact with electrical currents, as well as in the emerging field of energy harvesting.

"We have long known that these polymers will eventually break down, or fail, when subjected to an increasing ," said Xuanhe Zhao, assistant professor of mechanical engineering and materials science at Duke's Pratt School of Engineering. He is the senior scientist in the series of experiments performed by a graduate student Qiming Wang and published online in the . "Now we can actually watch the process as it happens in real time."

The innovation the Duke team developed was attaching the soft polymer to another rigid polymer layer, or protective substrate, which enabled observation of the deformation process without incurring the breakdown. They then subjected this polymer-substrate unit to various electrical voltages and observed the effects under a microscope.

Creasing to cratering: Voltage breaks down plastic

Qiming Wang and Xuanhe Zhao are researchers at Duke University. Credit: Duke University Photography

"As bread dough rises in a bowl, the top surface of the dough may fold in upon itself to form creases due to compressive stresses developing in the dough," Zhao said, "Surprisingly, this phenomenon may be related to failures of electrical polymers that are widely used in energy-related applications."

"When the voltage reached a critical point, the compressive stress induced a pattern of creases, or folds, on the polymer," Zhao. "If the voltage is increased further, the creases evolved into craters or divots in the as the electrical stress pulls the creases open. Polymers usually break down electrically immediately after the creasing, which can cause failures of insulating cables and organic capacitors."

The substrate the researchers developed for the experiments not only allowed for the visualization of the creasing-to-cratering phenomenon, it could also be the foundation of a new approach to improving the ability of wires to carry electricity.

Provided by Duke University (news : web)


Silver-diamond composite offers cooling capabilities for electronics

Silver-diamond composite offers cooling capabilities for electronics


A microscope image of diamond particles. (Credit: Jason Nadler)

( -- Researchers at the Georgia Tech Research Institute (GTRI) are developing a solid composite material to help cool small, powerful microelectronics used in defense systems. The material, composed of silver and diamond, promises an exceptional degree of thermal conductivity compared to materials currently used for this application.

The research is focused on producing a silver-diamond thermal shim of unprecedented thinness – 250 microns or less. The ratio of silver to diamond in the material can be tailored to allow the shim to be bonded with low thermal-expansion stress to the high-power wide-bandgap semiconductors planned for next generation phased-array radars.

Thermal shims are needed to pull heat from these high-power semiconductors and transfer it to heat-dissipating devices such as fins, fans or heat pipes. Since the semiconductors work in very confined operating spaces, it is necessary that the shims be made from a material that packs high into a tiny structure.

Diamonds provide the bulk of thermal conductivity, while silver suspends the diamond particles within the composite and contributes to high thermal conductivity that is 25 percent better than copper. To date, tests indicate that the silver-diamond composite performs extremely well in two key areas -- thermal conductivity and thermal expansion.

'We have already observed clear performance benefits -- an estimated temperature decrease from 285 degrees Celsius to 181 degrees Celsius -- using a material of 50 percent diamond in a 250-micron shim,' said Jason Nadler, a GTRI research engineer who is leading the project.

The researchers are approaching diamond percentages that can be as high as 85 percent, in a shim less than 250 microns in thickness. These increased percentages of diamond are yielding even better performance results in prototype testing.

Nadler added that this novel approach to silver-diamond composites holds definite technology-transfer promise. No material currently available offers this combination of performance and thinness.

Natural Thermal Conductors

Diamond is the most thermally conductive natural material, with a rating of approximately 2,000 watts per meter Kelvin, which is a measure of thermal efficiency. Silver, which is among the most thermally conductive metals, has a significantly lower rating -- 400 watts per meter K.

Nadler explained that adding silver is necessary to:

- bond the loose diamond particles into a stable matrix;
- allow precise cutting of the material to form components of exact sizes;
- match thermal expansion to that of the semiconductor device being cooled;
- create a more thermally effective interface between the diamonds.

Nadler and his team use diamond particles, resembling grains of sand, that can be molded into a planar form.

The problem is, a sand-like material doesn't hold together well. A matrix of silver -- soft, ductile and sticky -- is needed to keep the diamond particles together and achieve a robust .

Silver-diamond composite offers cooling capabilities for electronics

This image shows different preparations of diamonds, ready for integration into a silver matrix. (Credit: Gary Meek)

In addition, because the malleable silver matrix completely surrounds the diamond particles, it supports cutting the composite to the precise dimensions needed to form components like thermal shims. And silver allows those components to bond readily to other surfaces, such as semiconductors.

Tailoring Thermal Expansion

As any material heats up, it expands at its own individual rate, a behavior known as its coefficient of thermal expansion (CTE).

When structures made from different materials -- such as a wide-bandgap semiconductor and a thermal shim -- are joined, it is vital that their thermal-expansion coefficients be identical. Bonded materials that expand at different rates separate readily.

Diamond has a very low coefficient of thermal expansion of about two parts per million/Kelvin (ppm/K). But the materials used to make wide-bandgap semiconductors -- such as silicon carbide or gallium nitride – have higher CTEs, generally in the range of three to five ppm/K.

By adding in just the right percentage of silver, which has a CTE of about 20 ppm/K, the GTRI team can tailor the silver-diamond composite to expand at the same rate as the semiconductor material. By matching thermal-expansion rates during heating and cooling, the researchers have enabled the two materials to maintain a strong bond.

Unlike metals, which conduct heat by moving electrons, diamond conducts heat by means of phonons, which are vibrational wave packets that travel through crystalline and other materials. Introducing silver between the diamond-particle interfaces helps phonons move from particle to particle and supports thermal efficiency.

"It's a challenge to use diamond particles to fill space in a plane with high efficiency and stability," Nadler said. "In recent years we've built image-analysis and other tools that let us perform structural morphological analyses on the material we've created. That data helps us understand what's actually happening within the composite -- including how the diamond-particle sizes are distributed and how the actually surrounds the ."

A remaining hurdle involves the need to move beyond performance testing to an in-depth analysis of the silver-diamond material's functionality. Nadler's aim is to explain the thermal conductivity of the composite from a fundamental materials standpoint, rather than relying solely on performance results.

The extremely small size of the thermal shims makes such in-depth testing difficult, because existing testing methods require larger amounts of material. However, Nadler and his team are evaluating several testbed technologies that hold promise for detailed thermal-conductivity analysis.

Multiplexed capillary isoelectric focusing increases efficiency in protein measurements

The Springer journal Analytical and Bioanalytical Chemistry (ABC) has chosen Oluwatosin O. Dada (34) as the recipient of its Best Paper Award 2010. Dada is the lead author of a paper in ABC on capillary isoelectric focusing. The award, accompanied by 1,000 euros, was created by Springer to help exceptional young scientists establish their research careers. The ABC Best Paper Award has been given since 2005.

Capillary isoelectric focusing is an interesting technique for the characterization of proteins. However, multiplexing capillary isoelectric focusing is a daunting task. Dr. Dada's significant contribution to this technology is the development of a state-of-the-art tool for high-throughput capillary isoelectric focusing. The performance of this technology is stunning: It provides the highest throughput isoelectric focusing analysis ever reported, the highest sensitivity ever reported for a high-throughput instrument, and the highest resolution separation ever reported for capillary isoelectric focusing. The technology will find wide application, including characterization of recombinant and , the diagnosis of disease, and the study of systems biology.

Dr. Dada received his BSc in industrial chemistry in 2001 from Olabisi Onabanjo University in Nigeria. He moved to the United States in 2004, where he received his PhD in from Utah State University in 2008. He then spent two years at the University of Washington in Seattle as a postdoctoral research associate. Currently, he holds a research assistant professor position at the University of Notre Dame, USA, where he continues his research on capillary electrophoresis with laser-induced fluorescence and photothermal instrumentation for bioanalysis.

Prof. Aldo Roda, Editor of , said, "There is a highly competitive effort underway in the scientific community to improve the analytical performance of isoelectric focusing (IEF) as a tool for protein separation and concentration. Several groups have investigated the miniaturization of cIEF and the integration of cIEF to a microchip format. With this paper, Dada and co-workers offer us new analytical approaches to resolving the ongoing problem of time-consuming procedures."

More information: The article "Capillary array isoelectric focusing with laser-induced fluorescence detection" is freely available online on SpringerLink at http://www.springe … 71l58435h58/

Provided by Springer