Chemistry News Archive February 2008

Easing concerns about pollution from manufacture of solar cells

In a finding that could help ease concerns about the potential environmental impact of manufacturing solar cells, scientists report that the manufacture of solar cells produces far fewer air pollutants than conventional fossil fuel technologies. Their report, the first comprehensive study on the pollutants produced during the manufacture of solar cells, is scheduled for the March 15 issue of the ACS' Environmental Science & Technology, a semi-monthly publication.

Solar energy has been touted for years as a safer, cleaner alternative to burning fossil fuels to meet rising energy demands. However, environmentalists and others are increasingly concerned about the potential negative impact of solar cell (photovoltaic) technology. Manufacture of photovoltaic cells requires potentially toxic metals such as lead, mercury and cadmium and produces carbon dioxide, which contributes to global warming.

In the new study, Vasilis M. Fthenakis and colleagues gathered air pollution emissions data from 13 solar cell manufacturers in Europe and the United States from 2004-2006. The solar cells include four major commercial types: multicrystalline silicon, monocrystalline silicon, ribbon silicon, and thin-film cadmium telluride. The researchers found that producing electricity from solar cells reduces air pollutants by about 90 percent in comparison to using conventional fossil fuel technologies. - MTS

Environmental Science & Technology: �Emissions from Photovoltaic Life Cycles�.

Acid-seeking �warheads� promise safer, more effective cancer weapons

Researchers in California report development of an anti-cancer �warhead� that targets the acidic signature of tumor cells in much the same way that heat-seeking missiles seek and destroy military targets that emit heat. These acid-seeking substances are not toxic to healthy cells, and represent a new class of potentially safer, more effective anti-cancer drugs, they say. Their study is scheduled for the March 6 issue of ACS� The Journal of Physical Chemistry B, a weekly publication.

For years, scientists tried to develop anti-cancer drugs based on enediynes, a powerful class of natural, tumor-fighting agents derived from soil bacteria. However, as these substances kill both cancerous and healthy cells, their effectiveness as anti-cancer drugs is limited.

In the new study, Elfi Kraka and colleagues describe making unusual substances that become highly active only in the presence of low pH levels, or acidic environments. Since cancer cells have highly acidic environments in comparison to normal cells, compounds containing these substances - called dynemicin-amidines (DADs) - target and destroy tumor cells without affecting healthy cells, the researchers say. The substances represent �the design of the first nontoxic enediyne antitumor drugs based on the DAD principle,� the report states. - MTS

The Journal of Physical Chemistry B: �Design of a New Warhead for the Natural Enediyne Dynemicin A. An Increase of Biological Activity."

Toward a healthier food for Fido: Corn provides promising fiber alternative

In addition to helping fill gasoline tanks with alcohol-based fuel, corn may have a new role in filling Fido�s bowl with more healthful food, nutritional biochemists in Illinois are reporting. They found that corn fiber shows promise as a more economical and healthier ingredient in dog food than some of the fibers now in use. Their study is scheduled for the March 26 issue of ACS� Journal of Agricultural and Food Chemistry, a bi-weekly publication.

George Fahey and colleagues point out that the fiber content of dog food varies widely and is often of inferior quality. Many dog foods use fiber from sugar beet pulp. Corn fiber - available in large amounts as a byproduct of ethanol production - is an attractive alternative. However, researchers have little information on corn fiber�s effects in dogs.

In the new study, researchers studied digestion, food intake, and fecal characteristics in dogs fed either a special food containing corn fiber or a standard food containing beet fiber. Substituting corn fiber for beet fiber �does not dramatically impact nutrient digestibility, food intake, or fecal production and characteristics,� the researchers say. Corn fiber should therefore be considered a promising fiber alternative for use in dog food, they note. Previous studies suggest that corn fiber in animal food could have beneficial effects in reducing risks of obesity and diabetes. - MTS

Journal of Agricultural and Food Chemistry: �Chemical Composition, in Vitro Fermentation Characteristics, and in Vivo Digestibility Responses by Dogs to Select Corn Fibers�

New electrodes may provide safer, more powerful lithium-ion (Li-ion) batteries

Researchers in Spain and the United Kingdom are reporting development of a new electrode material that could ease concerns about the safety of those unbiquitous lithium-ion (Li-ion) batteries, while giving Li-ion batteries a power boost, according to a new study. It is scheduled for the March 11 issue of ACS� Chemistry of Materials, a bi-weekly journal.

Li-ion batteries power an increasing number of laptop computers and portable electronic devices. They are now being eyed for motor vehicles of the future. However, recent recalls of millions of Li-ion batteries due to overheating have raised safety concerns, with researchers seeking new materials to make safer, more powerful batteries.

In the new study, M. Rosa Palac�n and colleagues compared the performance of Li-ion batteries made with electrodes composed of lithium nickel nitride (LiNiN) to conventional Li-ion batteries containing carbon electrodes. The new materials are more efficient than the conventional electrodes and less likely to overheat, the researchers suggest. They note that �further improvements can be envisaged by changing the reaction conditions and the processing of the electrode.� - MTS

Chemistry of Materials: �Towards New Negative Electrode Materials for Li-Ion Batteries: Electrochemical Properties of LiNiN�.

Deadly sugar plant blast underscores need for new regulations

The explosion at a sugar refinery in Georgia earlier this month that killed nine workers underscores the need for tougher industrial safety standards regarding production of combustible dust, according to an article scheduled for the Feb. 25 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

In the article, C&EN Senior Editor Jeff Johnson points out that hundreds of such dust explosions have occurred over the last 30 years. These explosions can occur without warning and can be triggered by a single spark. Most people do not realize that common substances such as sugar can become highly explosive after being processed into fine dust, whose tiny size requires less energy to ignite, the article notes. The risk grows as huge quantities of these tiny particles accumulate on floors, beams, ceilings and other areas.

Over the years, tighter federal regulations have already prevented combustible dust accidents at grain facilities. However, in light of the recent tragedy, experts feel that tougher, more uniform combustible dust standards and regulations should be expanded to cover all industries that produce combustible dust to prevent these disasters from occurring in the future, the article suggests. - MTS

Chemical & Engineering News: �Sugar Plant Blast Rekindles Dust Debate�.

Fighting �fat bloom� can mean a prettier look for Valentine�s Day chocolates

Chemists in England and the Netherlands have discovered a substance that could keep those boxes of Valentine�s Day chocolates, and other goodies, looking fresher and tastier. Their finding, which prevents formation of unsightly white films on the outside of chocolate, is scheduled for the March 12 issue of the ACS� Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Called �fat bloom,� white films are actually tiny particles of crystalline fat and most often appear on the surface of chocolates that contain nut-based fillings. The films often alarm consumers, who may mistakenly think good chocolates have gone bad. Although the blooms have been studied for decades, the phenomenon is poorly understood and researchers have had difficulty finding an effective method to reduce their formation.

In the new study, Kevin W. Smith and colleagues crafted a candy-size mechanical model of a chocolate bon-bon using a series of stacked, steel washers. They layered the bottom of each cylinder with different concentrations of a substance called �antibloom fat� and then filled the top of each cylinder with cocoa butter to represent a chocolate coating. The scientists showed that increasing the amount of �antibloom� used in the filling slowed the rate of crystal formation, thereby preventing fat bloom. - MTS

Journal of Agricultural and Food Chemistry: �Effect of Antibloom Fat Migration from a Nut Oil Filling on the Polymorphic Transformation of Cocoa Butter�.

A long-sought test for direct detection of disease-causing E. coli bacteria

Biochemists in Japan are reporting development of a long-sought direct test for identifying the presence E. coli bacteria that get into water and food as a result of fecal contamination. That contamination causes millions of cases of food poisoning and other gastrointestinal illness around the world each year. Their study is scheduled for the April 4 issue of ACS� Biotechnology Progress, a bi-monthly journal.

In the report, Yasunori Tanji and colleagues point out that tests now in use do not directly identify E. coli. Instead, these tests detect �coliform� bacteria that health officials use as indicators for fecal contamination. Coliforms, however, can originate from natural sources, and are not always reliable indicators of fecal contamination. Direct tests for E. coli do exist, but are too time-consuming and complex for general use.

The new study describes successful use of genetically engineered viruses that infect E. coli to identify a wide range of E. coli strains found in sewage. Researchers first engineered the viruses to be harmless to E. coli. Then they gave the viruses genes to produce green fluorescent proteins. The resulting viruses reveal the presence of E. coli by lighting up and glowing after infecting the bacteria. The test uses a fluorescent microscope to detect the glow and the presence of disease-causing bacteria, and takes only a few hours. - MTS

Biotechnology Progress: �Detection of Escherichia coli with Fluorescent Labeled Phages That Have a Broad Host Range to E. coli in Sewage Water�.

Study of �Ouzo effect� may lead to design of improved drugs, cosmetics

Scientists studying the cloudy emulsions produced by anise-flavored liquors such as Ouzo have discovered new molecular insights into their formation, findings that could lead to the design of better commercial emulsions used in making pharmaceuticals, food products, cosmetics and other materials. Their study is scheduled for the Feb. 19 issue of ACS� Langmuir, a bi-weekly publication.

Although transparent when bottled, Ouzo, Pastis, Pernod, and other popular anise-flavored alcoholic beverages form milky-white emulsions when diluted with water prior to drinking, a phenomenon commonly known as the �Ouzo effect.� These emulsions occur spontaneously and are stable for weeks and even months, a feature that is attractive to industry. However, scientists are unclear how these mixtures form and stabilize.

In the new study, Erik van der Linden and colleagues measured the stability of various emulsions prepared from commercial Pernod and compared the results to theoretical predictions of their formation. The scientists found that their experimental observations were often opposite the predicted behavior of the emulsions in the presence of various concentrations of oil, water, and alcohol components. �More knowledge of the parameters that determine the stability of these emulsions, besides interfacial tension, solubility, and density difference, might lead to better control of the emulsification process,� the study states. - MTS

Langmuir: �The Life of an Anise-Flavored Alcoholic Beverage: Does Its Stability Cloud or Confirm Theory?�.

New transportation technology for microcargoes

Scientists in Japan are reporting the discovery of a new transportation technology for moving ultra-small cargoes in the coming generation of micromachines and laboratories-on-a-chip. The report by Kenichi Yoshikawa and colleagues is scheduled for the March 6 issue of ACS� Journal of Physical Chemistry, a weekly publication.

The study describes successful delivery of a simulated microcargo of paper with chemical waves produced by a reaction that has fascinated scientists and students for 50 years. Termed the Belousov-Zhabotinsky (BZ) reaction, it produces a continuing series of waves in a water solution.

In the report, researchers describe the first use of those waves to move objects in a directed, controlled fashion. �They can be used for the transport of material objects through a desired delivery route,� the report states. �The combination of carrying and controlling waves with the proper timing of initiation allows us, in principle, to deliver freight over a chosen path, with the ability to switch the path if desired.� - MW

Journal of Physical Chemistry: �Microfreight Delivered by Chemical Waves�.

Improved polymers for lithium ion batteries pave the way for next generation of electric and hybrid cars

The next generation of electric and hybrid cars may be a step closer thanks to new and improved polymer membranes that allow the development of bigger, safer, and more powerful lithium ion batteries, according to an article scheduled for the Feb. 18 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

In the article, C&EN Senior Editor Alexander H. Tullo notes that polymer membranes are already an essential component of lithium ion batteries that power iPods, laptop computers, and other portable electronic devices. These porous, hair-thin separators control the flow of electrons through the battery. Their failure can result in overheating and even fires. Such problems have recently prompted the widespread recall of millions of lithium ion batteries.

Tullo points out that lithium ion batteries will need to be bigger, safer, and more powerful if they are to be used effectively in motor vehicles. For that purpose, improved polymer separators are needed. Recently, battery manufacturers have stepped up to this challenge by developing new polymer separators with greater porosity for improved power flow and stronger insulation materials for improved safety. At least one manufacturer is already using a new type of polymer separator in a new line of electric vehicles, while other advanced polymers are making their way through the development pipeline, according to the article. �The reality of driving to work under electric power may only be a hair away,� Tullo says.

Chemical & Engineering News: �The Power of Pores�.

�Recordable� proteins as next-generation memory storage materials

Move over, compact discs, DVDs, and hard drives. Researchers in Japan report progress toward developing a new protein-based memory device that could provide an alternative to conventional magnetic and optical storage systems, which are quickly approaching their memory storage capacities. Their study is scheduled for the March 4 issue of ACS� Langmuir, a bi-weekly journal.

Just as nature chose proteins as the memory storage medium of the brain, scientists have spent years exploring the possibility of similarly using proteins and other biological materials to build memory-based devices with the potential for processing information faster and providing greater storage capacity than existing materials. Although a few protein-based memory materials have shown promise in experimental studies, developing such materials for practical use remains a challenge.

In the new study, Tetsuro Majima and colleagues used a special fluorescent protein to etch or �record� a specific information pattern on a glass slide. Using a novel combination of light and chemicals, the researchers demonstrated that they could �read� the pattern and subsequently erase it at will. Thus, they demonstrated that the proteins could provide storage, playback, and erasure of information, the hallmarks of a successful memory device, the researchers say. In addition to conventional memory storage devices, the proteins also show promise for improved biosensors and diagnostic tests, they say. - MTS

Langmuir: �Protein Recording Material: Photorecord/Erasable Protein Array Using a UV-Eliminative Linker�

At last a machine with good taste - for espresso

Can a machine taste coffee" The question has plagued scientists studying the caffeinated beverage for decades. Fortunately, researchers in Switzerland can now answer with a resounding �yes.� The study on their coffee-tasting machine is scheduled for the March 1 issue of ACS� Analytical Chemistry, a semi-monthly journal.

For the food industry, �electronic tasters� like these could prove useful as quality control devices to monitor food production and processing. Christian Lindinger and colleagues at Nestl� Research pointed out that coffee scientists have long been searching for instrumental approaches to complement and eventually replace human sensory profiling. However, the multisensory experience from drinking a cup of coffee makes it a particular challenge for flavor scientists trying to replicate these sensations on a machine. More than 1,000 substances may contribute to the complex aroma of coffee.

The new tasting machine assessed the taste and aromatic qualities of espresso coffee nearly as accurately as a panel of trained human espresso tasters, the study reported. It analyzed gases released by a heated espresso sample, then transformed the most pertinent chemical information into taste qualities like roasted, flowery, woody, toffee and acidity. �This work represents significant progress in terms of correlation of sensory with instrumental results exemplified on coffee,� state the authors. - AD

Analytical Chemistry: �When Machine Tastes Coffee: Instrumental Approach to Predict the Sensory Profile of Espresso Coffee�

Toward �self-cleaning� wool and silk fabrics

Wool skirts and silk ties may avoid those pricey trips to the dry-cleaner in the future and clean themselves, researchers in Australia and China suggest in a study scheduled for the Feb. 26 issue of ACS� Chemistry of Materials, a bi-weekly journal. It reports development of a nanoparticle coating that could lead to �self-cleaning� wool and silk fabrics.

Wool and silk, which are composed of natural proteins called keratins, are among the most prized and widely used fabrics in the clothing industry. However, they are difficult fabrics to keep clean and are easily damaged by conventional cleaning agents. A better way to fight stains in these and other protein-based fabrics is needed, scientists say.

In the new study, Walid Daoud and colleagues prepared wool fabrics with and without a nanoparticle coating composed of anatase titanium dioxide, a substance that is known to destroy stains, dirt, and harmful microorganisms upon exposure to sunlight. The researchers then stained the fabric samples with red wine. After 20 hours of exposure to simulated sunlight, the coated fabric showed almost no signs of the red stain, whereas the untreated fabric remained deeply stained, the researchers say. The coating, which is non-toxic, can be permanently bonded to the fiber and does not alter its texture and feel, they note. - MTS

Chemistry of Materials: �Self-Cleaning Keratins�

Personalized medicine: Moving forward slowly but surely

With its promises of more effective, low-cost therapies for cancer, heart disease, Alzheimer�s and other medical conditions, personalized medicine is moving forward but at a slow pace that�s not keeping up with its high expectations, according to an article scheduled for the Feb. 11 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

In the magazine�s cover story, C&EN Senior Editor Rick Mullin notes that personalized medicine, the practice of catering medical therapies to the specific genetic and disease profiles of patients, represents a major shift from the one-size-fits-all model of traditional medicine. Despite its promise, researchers have had difficulty translating new genetic knowledge into effective therapies.

But fueled by new research tools and new genetic information, the field is silently moving forward. Notable successes include the development of Herceptin, a targeted therapy for breast cancer, and Gleevec, a treatment for lung cancer. Other targeted therapies are in the pipeline. �We are at a kind of crossroads where we have developed a large number of new agents with pharmacologically sound activities,� C&EN quotes one researcher. �But clearly, to hit the home run, you have to match the right drug to the right patient. It�s easier said than done.�

Chemical & Engineering News: �Personalized Medicine�

Iodized table salt may be low in iodine, raising health concerns

Amid concern that people in the United States are consuming inadequate amounts of iodine, scientists in Texas have found that 53 percent of iodized salt samples contained less than the U.S. Food and Drug Administration (FDA) recommended level of this key nutrient. Iodized table salt is the main source of iodine for most individuals, they note in a study scheduled for the Feb. 15 issue of ACS� Environmental Science & Technology, a semi-monthly journal.

Purnendu K. Dasgupta and colleagues point out that iodine intake has been decreasing in the United States for decades. The reasons include reduced use of iodine-based additives in livestock feed and bread, and public health warnings about salt�s role in high blood pressure. Iodine is especially important for normal brain development in newborn infants and children, they state, noting a link between iodine deficiency and attention deficit disorder or ADD that has been suggested by other researchers.

To assess the adequacy of iodine nutrition, the researchers tested 88 samples of iodized salt and found that 47 did not meet the FDA�s recommended level. In addition, amount of iodine varied in individual packages and brands of salt. The researchers expressed particular concern about the adequacy of iodine nutrition in women who are pregnant or nursing. �If salt does supply a significant portion of the iodine intake of a pregnant/lactating woman in the United States (note that a large fraction of postnatal vitamins contain no iodine), and she is unfortunate enough to pick a can of salt that is low in iodine or in which distribution is greatly uneven, there is a potential for serious harm,� the study states. - JS

Environmental Science & Technology: �Iodine Nutrition: Iodine Content of Iodized Salt in the United States�.

New test answers frustrating question: Is Tweety a boy or a girl"

Scientists in Germany are reporting development of test that can answer one of the most frustrating questions in the animal kingdom: Is that bird a boy or a girl" Their study, a potential boon to poultry farmers and bird breeders, is scheduled for the Feb. 15 issue of ACS� Analytical Chemistry, a semi-monthly journal.

Juergen Popp and colleagues point out that the boy-girl question can be difficult to answer in birds that lack distinctive, gender-related plumage. Since birds lack external genital organs, sexing a bird typically involves endoscopic examination of the animal�s gonads under general anesthesia or specific molecular biological methods. Since these methods are expensive, time-consuming, and stressful for the bird, scientists long have sought a quick, minimal-invasive sexing alternative.

In the new study, researchers describe such a test, which involves analysis of tissue pulp from birds� feathers using a highly sensitive lab instrument. The method, called ultraviolet-resonance Raman (UVRR) spectroscopy, took less than a minute, and identified the birds� sex with 95 percent accuracy, the scientists say. - MTS

Analytical Chemistry: �Minimal Invasive Gender Determination of Birds by Means of UV-Resonance Raman Spectroscopy�.

Toward an effective treatment for monkeypox

Researchers in Washington and Oregon report an advance toward developing much-needed new drugs and vaccines for monkeypox. The disease occurs mainly among rodents, monkeys, and other animals in Africa, but has been transmitted to humans resulting in high mortality rates. Although this deadly viral disease rarely occurs naturally in the United States, it is a potential bioterrorism agent.

In an article scheduled for the March issue of the ACS' Journal of Proteome Research, Richard D. Smith and colleagues note that monkeypox is caused by a virus closely-related to smallpox. Naturally occurring smallpox has been eradicated worldwide thanks to a vaccine that has occasional serious side-effects. However, no safe and proven vaccine or effective medication currently exists for monkeypox.

In their study, mass spectrometry and other sensitive lab techniques were used to compare proteins produced by both monkeypox virus (MPV) and by the vaccinia virus (VV), which is the basis for current smallpox vaccines. The researchers identified nine proteins that were specific to MPV and eight that were specific to VV. Importantly, proteins present in MPV, but absent in VV seem to be critical for the high virulence of MPV, they point out. This knowledge may be the key to the development of new medications and vaccines for preventing and treating monkeypox, as well as to the production of safer versions of more general pox-related vaccines, the researchers say.

Journal of Proteome Research: �Comparative Proteomics of human Monkeypox and Vaccinia Intracellular Mature and Extracellular Enveloped Virions�.

Fungus among us: Invisible �micropollutants� invade crops, water supply

They�re here, there, and everywhere: Toxins produced by a common fungus are spreading beyond food crops and invading the environment, including water supplies, with unknown consequences, researchers in Switzerland report. Their study, which reveals a need for stronger monitoring and control of these overlooked �micropollutants,� is scheduled for the Feb. 13 issue of ACS� Journal of Agricultural and Food Chemistry, a bi-weekly publication.

The contaminants are members of a larger family fungal-produced toxins called mycotoxins. In the report, Thomas Bucheli and colleagues note that scientists have studied two of the most common mycotoxins - deoxynivalenol and zearalenone - in food and animal feed products for decades. However, scientists know very little about the distribution of these toxins elsewhere in the environment.

In the new study, the researchers exposed a winter wheat field to Fusarium graminearum, a major fungal source of deoxynivalenol and zearalenone, and subsequently monitored these toxins in the field�s drainage water before, during and after harvest. Using high-tech lab instruments, they found that levels of these toxins increased significantly after harvest. Levels of deoxynivalenol, for instance, rose by almost 4,000-fold. Traces of these toxins were also found in a number of Swiss rivers, they note.

Journal of Agricultural and Food Chemistry: "Fusarium Mycotoxins: Overlooked Aquatic Micropollutants".

China�s new Great Leap Forward - in drug discovery

In a modern-day counterpart to Mao Zedong�s program to modernize the Chinese economy, China�s pharmaceutical industry is quietly taking its own Great Leap Forward - as a major force in drug discovery and development, according to an article scheduled for the Feb. 4 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

China already is an important source of active ingredients that large pharmaceutical companies in the United States and other countries use to make prescription and over-the-counter drugs. C&EN�s cover story, by Senior Correspondent Jean-Fran�ois Tremblay, notes that China is playing an increasingly important, yet mostly unrecognized role in drug discovery. Companies based in China that undertake research projects on behalf of foreign companies have in the past three years beefed up their range of services. From Shanghai to Beijing, new companies are being launched with research capabilities that, in terms of the time it takes to produce results, exceed those of Western pharmaceutical companies. A growing number of Chinese firms offer a full range of drug research and development services, including synthesis, process research and scale up, and animal testing, the article states. Within two years, the first drug to be mostly developed in China could begin human trials in the U.S., Tremblay says.

The growth in pharmaceutical services in China seems to be part of a major trend. �Last century, we saw the pharmaceutical industry move from Europe to the United States,� C&EN quotes a manager at one drug discovery company. �Now, it�s perhaps moving to China and India.�

Chemical & Engineering News: "China�s Pharma Leaps into Discovery".