Chemistry News Archive March 2008

New triple-threat weapon needed in war between man and microbe

Mankind�s age-old battle against infectious diseases stands to rage on and on, unless scientists develop a new generation of triple-action antibiotics, according to an article scheduled for the March 28 issue of ACS� monthly Journal of Natural Products.

In the article, Lester A. Mitscher presents a �rather personalized� account of the turbulent tug-of-war between microbes and mankind, describing past tactics, lessons learned, and a cautious prediction about the road ahead.

Mitscher notes, for instance, that �miracle drugs� in the 1940s and �50s failed to live up to expectations. Though penicillin promised an end to infections worldwide in 1941, reports of resistant bacteria appeared only a year later. �Significant clinical resistance is now known for virtually all antibiotics in medical use,� the article states. �Unfortunately, the problem is getting worse since big pharma has largely withdrawn from research directed toward new antibiotic discovery.�

The review concludes that microbial resistance is inevitable pending unforeseen breakthroughs. One involves development of new antibiotics that go beyond killing or slowing the growth of disease-causing microbes. Those new medications would contain antimutagenic ingredients that discourage bacteria from mutating into resistant forms. In addition, they would pack immunostimulants that enlist the body�s own immune defense system to fight off an infection. �Continued close observation and exploitation of natural phenomena appear at present to be the wisest course for scientists to follow in trying to deal with this problem,� says Mitscher. - AD

Journal of Natural Products "Coevolution: Mankind and Microbes"

Water pollution continues at famous Russian lake

Despite widespread concerns about preserving the world�s largest body of fresh water, researchers report that pollution is continuing in Russia�s fabled Lake Baikal. The study is scheduled for the April 15 issue of ACS� Environmental Science & Technology, a semi-monthly journal.

The deepest lake in the world, Lake Baikal holds 20 percent of the world�s unfrozen freshwater and is home to more than 1,500 species found nowhere else on earth. But compared to other areas in the world such as North America and Western Europe, little is known about the regional contamination to plant and animal life from compounds called perfluorochemicals (PFCs), the article says.

In the study, Hisato Itawa and colleagues measured levels of PFCs in the livers and sera of Baikal seals - the only entirely freshwater seal species in the world - and then compared them to recorded levels in 1992. They found that several chemicals were elevated to indicate an ongoing source of contamination in the lake. �Given these results, continuous monitoring of PFCs as well as dioxin-like compounds in Baikal seals is necessary to assess potential biological effects of PFCs,� the report says. The researchers noted a commercially manufactured PFC known as perfluorononanoic acid to be highest in the Baikal seals. - JS

Environmental Science & Technology: "Contamination and Effects of Perfluorochemicals in Baikal Seal (Pusa sibirica). 1. Residue Level, Tissue Distribution, and Temporal Trend."

A chemical �keypad lock� for biomolecular computers

Researchers in New York are reporting an advance toward a new generation of ultra-powerful computers built from DNA and enzymes, rather than transistors, silicon chips, and plastic. Their report on development of a key component for these �biomolecular computers� is scheduled for the March 26 issue of ACS� Journal of the American Chemical Society, a weekly publication.

In the new study, Evgeny Katz and colleagues describe development of a chemical �keypad lock,� one of the first chemical-based security systems of its kind. The researchers note that years of effort have gone into developing biomolecular computers, which rely on chemical reactions rather than silicon chips to perform logic functions. Among their uses would be encryption of financial, military, and other confidential information. Only individuals with access to a secret �key� - a chemical key - could unlock the file and access the data.

The research by Katz and colleagues solved one part of this technological challenge: The security code. They identified a series of naturally occurring chemical reactions that act as a �keypad lock.� In laboratory studies, they demonstrated that by adding the correct series of chemicals, the lock could be opened to access the computer. On the other hand, adding the incorrect chemicals to the system acts as a wrong password and prevents access to the computer, they say.

�In addition to the biomolecular security applications, the enzyme-based implication logic networks will be extremely important for making autonomous decisions on the use of specific tools/drugs in various implantable medical systems.� - MTS

Journal of the American Chemical Society: "Biocomputing Security System: Concatenated Enzyme-Based Logic Gates Operating as a Biomolecular Keypad Lock."

CSI fact catching up with fiction as chemists develop new technology

Real-life crime scene analysis of bloodstains, fingerprints, and other evidence does not match the speed and certainty on television shows such as CSI. But thanks to advances in chemistry, fact is catching up with fiction as researchers develop faster, more sensitive forensics tools, according to an article scheduled for the March 24 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

The article, written by C&EN Senior Editor Mitch Jacoby, describes up and coming forensics tools just unveiled at Pittcon, a major laboratory science conference held earlier this month in New Orleans. These new tools include a highly-sensitive method for identifying the specific dyes used to color acrylics, cotton, nylon, and other types of fibers, a technique that could help distinguish between fibers that appear similar. Other innovative tools include a handheld spectrometer for on-site detection of explosives and illegal drug residues and a long-lasting fluorescent dye solution that allows a longer, more detailed analysis of bloodstains than do conventional dyes.

The popularization of forensics on television has also spurred a new appreciation for this science among college students and the general public, the article suggests. But instant crime-solving remains the stuff of fiction. �Real chemists can�t always come up with solutions quite that fast. But they�re working on it,� Jacoby notes in the article.

Chemical & Engineering News: "Clues at the scene of the crime."

Heart-healthy yak cheese

In a finding likely to get cheese lovers talking, researchers in Nepal and Canada report that yak cheese contains higher levels of heart-healthy fats than cheese from dairy cattle, and may be healthier. Their study is scheduled for the March 12 issue of ACS� Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Producers make the cheese from the milk of yaks. Those long-haired humped animals are fixtures in Tibet and throughout the Himalayan region of south central Asia, Mongolia, and a few other countries. Yak cheese has only recently become available in the United States and is available in select gourmet food stores. Studies by others have shown that certain types of dairy-derived fatty acids, particularly conjugated linoleic acid (CLA), may help fight heart disease, cancer and even diabetes. However, little was know about the fatty acid composition of yak cheese.

In the new study, Brian W. McBride and colleagues compared the fatty acid composition of yak cheese from Nepal with that of cheddar cheese obtained from Canada. They found that levels of CLAs were four times higher in the yak cheese than the dairy cow cheese. Levels of polyunsaturated fatty acids, which are healthy for the heart, were also significantly higher in the yak cheese, the researchers say.

Journal of Agricultural and Food Chemistry: �Fatty Acid Composition of yak (Bos grunniens) Cheese Including Conjugated Linoleic Acid and trans-18:1 Fatty Acids�

Toward the next generation of high-efficiency plastic solar cells

Researchers in the United States and Austria report an advance toward the next generation of plastic solar cells, which are widely heralded as a low cost, environmentally-friendly alternative to inorganic solar cells for meeting rising energy demands. Their study is scheduled for the March 19 issue of ACS� Journal of the American Chemical Society, a weekly publication.

Alan J. Heeger and colleagues point out that plastic solar cells, fabricated from bulk heterojunction materials comprising semiconducting polymers and fullerenes, have already demonstrated promising performance. However, researchers do not understand how to control the nano-scale morphology and are looking for ways to optimize the solar cell performance for practical use. Heeger, co-recipient of the Nobel Prize in Chemistry in 2000 for his pioneering research on conducting polymers, is widely recognized for his ongoing efforts to improve solar cell efficiencies.

In the new study, Heeger and colleagues found that adding a class of chemicals called alkanedithiols as processing additives improves both the morphology and the solar cell performance.They showed that by utilizing alkanedithiols as processing additives, the efficiency of the plastic solar cells increased from 3.4 percent to 5.1 percent, among the highest efficiencies achieved to date for this type of solar cell. �These data provide a better understanding of correlation between the nano-scale morphology of the bulk heterojunction film and the solar cell performance,� the report states.

Journal of the American Chemical Society: �Processing Additives for Improved Efficiency from Bulk Heterojunction Solar Cells�

A new industrial-scale process for making big molecules with a big future

Scientists are reporting discovery of a new method that will enable manufacturers to produce industrial-size batches of dendrimers for the first time. Dendrimers are giant molecules with tree-like branches with a range of potentially valuable commercial and industrial applications. The study is scheduled for the March 21 issue of ACS� monthly Journal of Organic Chemistry.

Dendrimers can be produced in custom-designed shapes, sizes, structures and weights suitable for specific uses. Those potential applications range from drug delivery and gene transfer to new materials, coatings, sensors, and herbicides. But because they require multiple steps to make, dendrimers are difficult to produce on an industrial scale.

In their new study, Abdellatif Chouai and Eric E. Simanek describe a practical large-scale synthesis of dendrimers that sidestep this barrier. Their method yields a so-called �uncommitted intermediate,� a dendrimer scaffolding that can be built upon in countless ways. This intermediate �can be elaborated into a wealth of diagnostic and therapeutic dendrimers - some of which are currently being explored in our laboratory,� the researchers add.

The Journal of Organic Chemistry: �Kilogram-Scale Synthesis of a Second-Generation Dendrimer Based on 1,3,5-Triazine Using Green and Industrially Compatible Methods with a Single Chromatographic Step�

New aspirin-like substances may provide safer way to fight heart disease

Researchers in Italy report development of a new group of aspirin-like substances that may be safer and as effective as conventional aspirin for fighting heart disease, the leading cause of death in the developed world. Their study is scheduled for the March 27 issue of the ACS� Journal of Medicinal Chemistry.

Physicians have known for years that daily low-doses of aspirin, or acetylsalicylic acid, reduce the risk of developing heart attacks and stroke in some people. However, prolonged use of aspirin can damage the stomach lining, causing bleeding and ulcers that can be life-threatening. A safer form of aspirin is needed, researchers say.

In the new study, Alberto Gasco and colleagues designed a new form of aspirin by attaching a special chemical structure - called a nitrooxy-acyl group - that allows the drug to resist breakdown by stomach acidity while promoting its absorption by the blood. In laboratory tests using animal models, the new �aspirin-like� substances showed anti-inflammatory activities similar to regular aspirin and caused reduced or no damage to stomach tissue in comparison to equivalent amounts of regular aspirin. Some molecules also reduced platelet aggregation and promoted artery expansion, which are hallmarks of improved heart health, the researchers note.

Journal of Medicinal Chemistry : �Searching for New NO-donor Aspirin-like Molecules: A New Class of Nitrooxy-acyl Derivatives of Salicylic Acid�

Coal reemerges as important raw material in chemical manufacturing industry

With oil prices hovering around $100 per barrel, coal is reemerging as a key raw material in the manufacture of the basic chemical materials used to make plastics, fertilizers, and hundreds of other products, according to an article scheduled for the March 17 issue of Chemical & Engineering News, ACS� weekly news magazine.

The article, written jointly by C&EN Senior Editor Alex Tullo and Hong Kong-based senior correspondent Jean-Francois Tremblay, notes that coal has been used in the chemical manufacturing industry since the 19th century. Over the years, oil and natural gas gradually eclipsed coal to become the raw materials of choice for manufacturing a wide range of high-volume chemicals. But these days, the high prices of oil and natural gas have given coal - which costs a fraction of the price of crude oil - a substantial cost advantage, the article notes.

Coal�s potential as a raw material is greatest in China, the United States, and India, the article points out. These countries have about half the world�s coal reserves. Coal can be transformed into a gas and subsequently into basic chemical ingredients like ethylene and propylene that are used in the manufacture of hundreds of products, according to the article. Coal �is a relatively cheap feedstock,� declares one expert cited in the article. �It certainly has the ability to compete in today�s world.�

Chemical & Engineering News: �The New Black�

Sniffing out uses for the �electronic nose�

Despite 25 years of research, development of an �electronic nose� even approaching the capabilities of the human sniffer remains a dream, chemists in Germany conclude in an overview on the topic. Their review of R&D on digital noses is in the current issue of ACS� monthly journal Chemical Reviews.

In the article, Udo Weimar and colleagues describe major advances that have produced olfactory sensors with a range of uses in detecting certain odors. Electronic noses excel, for instance, at picking up so-called �non-odorant volatiles� - chemicals that mammalian noses cannot pick up like carbon monoxide. Ideally, however, an electronic nose should mimic the discrimination of the mammalian olfactory system for smells - reliably identifying odors like �fruity,� �grassy� and �earthy� given off by certain chemicals. Until electronic noses become more selective, their roles probably will be limited to serving as valuable tools for tasks such as monitoring air quality and detecting explosives.

�The electronic nose has the potential to enter our daily life far away from well-equipped chemical laboratories and skilled specialists,� the article states. �Keeping its limitations in mind and adapted for a special purpose, this will be the future for the electronic nose for as long as the ability to smell odors rather than detect volatiles is still far away over the rainbow.� - AD

Chemical Reviews: "Electronic Nose: Current Status and Future Trends"

Thirsty hybrid and electric cars could triple demands on scarce water resources

Eco-minded drivers in drought-prone states take note: A new study concludes that producing electricity for hybrid and fully electric vehicles could sharply increase water consumption in the United States. It is scheduled for the June 1 issue of ACS� Environmental Science & Technology, a semi-monthly journal.

In the study, Carey W. King and Michael E. Webber note that policy makers often neglect the impact that fleets of hybrid and electric vehicles could have on already-scarce water resources. They calculated water usage, consumption, and withdrawal during petroleum refining and electricity generation in the United States. Each mile driven with electricity consumes about three times more water (0.32 versus 0.07-0.14 gallons per mile) than with gasoline, the study found.

�This is not to say that the negative impacts on water resources make such a shift undesirable,� King and Webber emphasized. �Rather this increase in water usage presents a significant potential impact on regional water resources and should be considered when planning for a plugged-in automotive economy.� - AD

Environmental Science & Technology: �The Water Intensity of the Plugged-In Automotive Economy�

Researchers develop more computer-aided drug design

Researchers in Germany report an advance toward the much awaited era in which scientists will discover and design drugs for cancer, arthritis, AIDS and other diseases almost entirely on the computer, instead of relying on the trial-and-error methods of the past. Their study is scheduled for the March 24 issue of ACS� Journal of Chemical Information and Modeling, a bi-monthly publication.

In the report, Michael C. Hutter and colleagues note that computer-aided drug design already is an important research tool. The method involves using computers to analyze the chemical structures of potential drugs and pinpoint the most promising candidates. Existing computer programs check a wide range of chemical features to help distinguish between drug-like and nondrug materials. These programs usually cannot screen for all features at the same time, an approach that risks overlooking promising drug-like substances.

In the new study, researchers describe a more gradual and efficient system. Their new program uses an initial quick screen for drug-like features followed immediately by a second, more detailed screen to identify additional drug-like features. They applied this new classification scheme to a group of about 5,000 molecules that had previously been screened for drug-like activity. The new strategy was more efficient at identifying drug-like molecules �whereby up to 92 percent of the nondrugs can be sorted out without losing considerably more drugs in the succeeding steps,� the researchers say. - MTS

Journal of Chemical Information and Modeling: �Gradual in Silico Filtering for Druglike Substances�.

Residential oil boilers raise health concerns for Northeastern U.S.

New research suggests that residential oil boilers, commonly used for home heating in the northeastern United States, should receive more attention as sources of air pollutants. The study - the first to identify certain specific air pollutants in home heating oil emissions - is scheduled for the April 1 issue of ACS� Environmental Science & Technology, a semi-monthly journal.

Homes in the New England and Central Atlantic States consume about 80 percent of the 25 billion gallons of home heating oil burned in the United States. Scientists have been aware of potential public health effects of those emissions. However, there has been little specific information about the nature of the emissions.

Michael D. Hays and colleagues tackled that knowledge gap in their new study, which aimed to obtain improved or missing pollutant information for the popular home heating source. Among the substances of concern identified in the study were fine particulate matter known to cause asthma, bronchitis, and other health problems. �The residential oil burner is a source of numerous hazardous air pollutants and ultrafine particles and, hence, may warrant more attention in the future than it has received so far,� say the authors.

The research was conducted as part of a long-term national research program designed to better characterize particulate matter and its chemical precursors. The results are used to improve source emissions inventories and support efforts to determine how specific sources contribute to pollutant concentrations measured in the atmosphere. - AD

Environmental Science & Technology: �Physical and chemical characterization of residential oil boiler emissions�.

Funding cuts jeopardize cleanup of nuclear waste sites

The Federal Government may need at least 20 years longer than previously planned - and an additional $50 billion - to clean up radioactive and hazardous wastes at nuclear weapons sites, according to an article scheduled for the March 10 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

The article, written by C&EN Senior Editor Jeff Johnson, cites a new U. S. Department of Energy (DOE) audit of its operations estimating that clean-up costs may reach $305 billion at about 25 sites where nuclear weapons materials were manufactured. That�s more than $50 billion above the Bush Administration�s earlier estimate. The audit also indicates that it may take until 2062 to finish the cleanup job, over 20 years longer than originally scheduled.

Still, the clean-up budget proposed this year by the Bush Administration is $5.5 billion, one of the lowest since the massive remediation effort began in the 1980s. The budget cuts may be particularly hard felt at large cleanup sites such as Washington State�s Hanford Nuclear Site, the most contaminated nuclear site in the country, the article suggests. Some officials fear that the cuts could delay cleanup of Hanford and other sites indefinitely.

Chemical & Engineering News: �DOE Falling Behind in Cleanups�

A nano-sensor for better detection of Mad Cow Disease agent

In an advance in food safety, researchers in New York are reporting development of a nano-sized sensor that detects record low levels of the deadly prion proteins that cause Mad Cow Disease and other so-called prion diseases. The sensor, which detects binding of prion proteins by detecting frequency changes of a micromechanical oscillator, could lead to a reliable blood test for prion diseases in both animals and humans, the researchers say. Their study is scheduled for the April 1 issue of ACS� Analytical Chemistry, a semi-monthly journal.

Prions are infectious proteins that can cause deadly nerve-damaging diseases such as Mad Cow Disease in cattle, scrapie in sheep, and a human form of Mad Cow Disease called variant Creutzfeldt-Jakob Disease. Conventional tests are designed to detect the proteins only upon autopsy and the tests are time-consuming and unreliable.

In the new study, Harold G. Craighead and colleagues describe a high-tech, nano-sized device called a nanomechanical resonator array. The device includes a silicon sensor, which resembles a tiny tuning fork, that changes vibrational resonant frequency when prions bind. Its vibration patterns are then measured by a special detector. In experimental trials, the sensor detected prions at concentrations as low as 2 nanograms per milliliter, the smallest levels measured to date, the researchers say. - MTS

Analytical Chemistry: �Prion Protein Detection Using Nanomechanical Resonator Arrays and Secondary Mass Labeling�.

The incredible, hypoallergenic egg: New process to help egg-allergy sufferers

People who suffer from egg allergies may soon be able to have their quiche and eat it too. Chemists in Germany and Switzerland report development of a new process that greatly reduces allergens in eggs and may lead to safer, more specialized food products for individuals with egg allergies. Their study is scheduled for the March 12 issue of ACS� Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Although unusual in adults, egg allergies are among the leading food allergies in infants and children. These allergies can cause severe stomach aches, and rashes. In extremely rare cases, death may occur. As a result, physicians advise those with egg allergies to avoid eggs or egg-based products. Some researchers have tried to reduce allergens in eggs, especially the pasteurized egg product (consisting of shelled eggs) widely used in the food industry. Until now, however, those efforts have been largely unsuccessful.

In the new study, Angelika Paschke and colleagues describe their process, which exposes raw eggs to a combination of high heat and enzymes to break down their main allergens. The researchers then tested their reduced-allergen egg against blood serum collected from people with egg allergies. The modified egg product was 100 times less allergenic than raw egg, the scientists say. It does not significantly affect flavor and texture when used in various products, they add. - MTS

Journal of Agricultural and Food Chemistry: �In Vitro Determination of the Allergenic Potential of Technologically Altered Hen�s Egg�.

Promising new material for capturing CO₂ from smokestacks

Scientists and engineers in Georgia and Pennsylvania are reporting development of a new, low-cost material for capturing carbon dioxide from the smokestacks of coal-fired electric power plants and other industrial sources before the notorious greenhouse gas enters the atmosphere. Their study is scheduled for the March 19 issue of the ACS� Journal of the American Chemical Society, a weekly publication.

In the new study, Christopher W. Jones and colleagues point out that existing carbon capture technology is unsuitable for wide use. Absorbent liquids, for instance, are energy intensive and expensive. Current solid adsorbents show promise, but many suffer from low absorption capacities and lack stability after extended use. Stronger, longer-lasting materials are needed, scientists say.

The scientists describe development of a new solid adsorbent coined a hyperbranched aminosilica (HAS) that avoids those problems. When compared to traditional solid adsorbents under simulated emissions from industrial smokestacks, the new material captured up to seven times more carbon dioxide than conventional solid materials, including some of the best carbon dioxide adsorbents currently available, the researchers say. The material also shows greater stability under different temperature extremes, allowing it to be recycled numerous times. - MTS

Journal of the American Chemical Society: �Designing Adsorbents for CO₂ Capture from Flue Gas-Hyperbranched Aminosilicas Capable of Capturing CO₂ Reversibly�.

Steel forges foundation for cheaper solar power

Steel forged railroads, skyscrapers and the automobile industry. Now it may help solar energy become cheaper and more widely available. In a study scheduled for the March 20 issue of ACS' weekly Journal of Physical Chemistry C, Finnish scientists report an advance in replacing the single most expensive component of a cutting-edge family of solar cells with less costly material.

These so-called �nanostructured dye solar cells (DSCs)� are a relatively new family of photovoltaic devices. Their simple manufacturing methods are hoped to lead to lower production costs compared to conventional solar cells. Traditionally, DSCs are deposited on conductively coated glass sheets which accounts for more than 30 percent of the material costs. Preparing DSCs on flexible stainless steel sheets is one way to reduce the costs and also to enhance mass production, according to Kati Miettunen and colleagues at the Helsinki University of Technology. Uncertainties existed, however, over the performance and stability of stainless steel photovoltaics.

In the new study, researchers describe construction of DSCs with stainless steel components and tests of the devices� performance. �It was shown that relatively high efficiencies can be obtained with DSC deposited on stainless steel substrate,� the study said. Subsequent work will investigate the durability of the stainless steel components and make further improvements in these promising solar devices. - AD

Journal of Physical Chemistry C: �Initial Performance of Dye Solar Cells on Stainless Steel Substrates�.

Money and creative freedom draw researchers to elite German research institution

With Germany�s Max Planck Society (MPS) establishing a biomedical research institute in the Sunshine State � a development that could help turn Florida into a Silicon Valley for biotechnology � an article scheduled for the March 3 issue of Chemical & Engineering News, ACS� weekly newsmagazine, provides readers with a behind the scenes look at this elite institution. The move represents the first time that an MPS site has been established in the United States, the reports says.

C&EN�s cover story by Associate Editor Sarah Everts notes that MPS operates a $2.5 billion annual budget to support cutting-edge, non-university research. Since its establishment in 1948, the group�s scientists have won 17 Nobel Prizes, including Gerhardt Ertl�s 2007 prize in chemistry. The Society has also funded key research into the development of improved polymers and high-tech light microscopy. Like the U.S.�s Howard Hughes Medical Institute, a wealthy nonprofit foundation that fund�s some of the nation�s top researchers, MPS has made a name for itself by giving exceptional researchers free reign to do creative and risky research.

Recently, MPS announced that it would establish a new biomedical branch in Florida. The new institute will focus on �devising non-invasive imaging methods to visualize molecular properties of biological tissue,� the article notes. Like the Sunshine State, MPS is keeping the future of research looking bright.

Chemical & Engineering News: �Max Planck Moves Stateside�.