Chemistry News Archive December 2007

Culinary shocker: Cooking can preserve, boost nutrient content of vegetables

In a finding that defies conventional culinary wisdom, researchers in Italy report that cooking vegetables can preserve or even boost their nutritional value in comparison to their raw counterparts, depending on the cooking method used. Their study is scheduled for the Dec. 26 issue of ACS� Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Nicoletta Pellegrini and colleagues note that although many people maintain that eating raw vegetables is more nutritious than eating cooked ones, a small but growing number of studies suggest that cooking may actually increase the release of some nutrients. However, scientists are seeking more complete data on the nutritional properties of cooked vegetables, the researchers say.

In the new study, the researchers evaluated the effects of three commonly-used Italian cooking practices - boiling, steaming, and frying - on the nutritional content of carrots, zucchini and broccoli. Boiling and steaming maintained the antioxidant compounds of the vegetables, whereas frying caused a significantly higher loss of antioxidants in comparison to the water-based cooking methods, they say. For broccoli, steaming actually increased its content of glucosinolates, a group of plant compounds touted for their cancer-fighting abilities. The findings suggest that it may be possible to select a cooking method for each vegetable that can best preserve or improve its nutritional quality, the researchers say. - MTS

Journal of Agricultural and Food Chemistry : �Effects of Different Cooking Methods on Nutritional and Physicochemical Characteristics of Selected Vegetables� [PDF]

 New report challenges idea that snuff is a �safer� substitute for cigarettes

A 20-year review of scientific research on tobacco and cancer challenges the idea that moist snuff - increasingly popular in the United States - can be a safer substitute for cigarette smoking. The review, by Stephen S. Hecht, is scheduled for the Jan. 1 issue of ACS� Chemical Research in Toxicology.

The paper, which covers the broad range of research on cancer induced by tobacco, points out that smokeless tobacco, a known cause of oral cancer, is contaminated with levels of cancer-causing nitrosamines that are generally 1,000 times greater than those found in any other consumer product. Despite health warning labels on packages of smokeless tobacco and a ban on electronic advertising, sales of snuff have continued to increase, the paper states.

�In the past several years, a new concept has emerged,� the paper notes. �Responsible members of the tobacco control community support the idea of using �low nitrosamine� moist snuff as a substitute for cigarette smoking. The rationale for this is that moist snuff is demonstrably less carcinogenic in humans, and less toxic in other ways, because it lacks the combustion products.� However, moist snuff products still contain significant levels of carcinogens, and users should stop, perhaps via use of nicotine replacement therapy, rather than switch from one risky product to another, the paper advises. - MTS

Chemical Research in Toxicology: �Progress and Challenges in Selected Areas of Tobacco Carcinogenesis� [PDF]

Toward improved non-stick surfaces at the flip of a switch

Researchers in New Jersey report development of a new type of non-stick material whose ability to shed liquids like water from a duck�s back can be turned on or off simply by flipping an electrical switch. The material, called �nanonails,� offers a wide-range of potential applications including contamination-resistant and self-cleaning surfaces, reduced-drag ships, and advanced electrical batteries, they say. Their study is scheduled for the Jan. 1 issue of ACS� Langmuir, a bi-weekly publication.

For years, researchers sought to develop surfaces that repel virtually any liquid. They�ve created non-stick surfaces that repel water and certain other liquids, but have had little success with repelling common organic liquids such as oils, solvents and detergents. Tom N. Krupenkin and colleagues report that their �nanonails� have all-purpose repellency properties. The nails actually are submicroscopic silicon structures shaped like carpenter�s nails that dramatically enhance a surface�s repellency. However, the surface becomes highly wettable when electricity is applied, allowing liquid to be sucked between the nails. In laboratory demonstrations, the researchers showed that their electronic non-stick surface works effectively using virtually any liquid.

�Nanonails� also show promise for enhancing chemical microreactions, decreasing flow resistance, and facilitating liquid movement for medical diagnostic applications such as lab-on-a-chip technology, they say. - MTS

Langmuir: �Nanonails: A Simple Geometrical Approach to Electrically Tunable Superlyophobic Surfaces� [PDF]

World�s only ultrafast electron microscope takes 4-D �movies� of molecules

A unique electron microscope that can help create four-dimensional �movies� of molecules may hold the answers to research questions in a number of fields including chemistry, biology, and physics, according to an article scheduled for the Dec. 24 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

In the article, C&EN Associate Editor Rachel Petkewich notes that the microscope, located at the California Institute of Technology, is a modified transmission electron microscope interfaced with an ultrafast laser. The ultrafast microscope is the only one capable of capturing four-dimensional pictures of molecules - 3-D structural changes over time - as they form and break apart, the writer states. These reactions occur at extremely fast rates - one billionth of one millionth of a second, or a �femtosecond� - that can�t be seen directly in real-time by other instruments. In 1999, Caltech chemist Ahmed H. Zewail, the lead scientist on the new work, was awarded the Nobel Prize in Chemistry for his pioneering studies of these ultrafast reactions.

Zewail and his colleagues are now making refinements to their ultrafast microscope and plan to capture a wider variety of images, including the details of whole cells, the writer notes. Caltech is negotiating an agreement with a microscope manufacturer to commercialize the instrument and make it available to other scientists, according to the article.

Chemical & Engineering News: �In the Niche of Time�

A faster, simpler test for disease biomarkers

In an advance toward earlier diagnosis of cancer and other disorders, scientists are reporting development of a potentially fast, simple and inexpensive blood test to detect disease �biomarkers.� The study is scheduled for the Dec. 26 issue of ACS� Journal of the American Chemical Society, a weekly publication.

Cagri A. Savran and colleagues explain that serum biomarkers can reveal critical information about the onset and progression of many diseases. Several roadblocks hinder clinical use of existing biomarker tests, which will demand smaller sensors, faster detection times, and less expensive ways of analyzing samples of blood and other body fluids.

The study describes development of an integrated serum biomarker detection system for the folate receptor and testing of blood samples from patients with different types of cancer. Researchers captured the folate receptors - proteins that are biomarkers for the growth of cancer cells - with microscopic magnetic beads and assembled them to form a structure termed a �diffraction grating.� A laser beam focused on the grating yielded a pattern that could potentially be used to determine the biomarker concentration and thus the state of tumor growth.

�The same principles presented here should apply for detection of many other disease markers present in various body fluids,� the researchers stated. �Due to its simplicity and high sensitivity, we expect this method to be extremely useful both in research laboratories and in development of devices for point-of-care diagnostics.� - AD

Journal of the American Chemical Society: �Immunomagnetic Diffractometry for Detection of Diagnostic Serum Markers� [PDF]

Marijuana smoke contains higher levels of certain toxins than tobacco smoke

Here�s another reason to �keep off the grass.� Researchers in Canada report that marijuana smoke contains significantly higher levels of several toxic compounds - including ammonia and hydrogen cyanide - than tobacco smoke and may therefore pose similar health risks. Their study, termed the most comprehensive to date on the chemical content of marijuana smoke, is scheduled for the Dec. 17 issue of ACS� Chemical Research in Toxicology, a monthly journal.

David Moir and colleagues note that researchers have conducted extensive studies on the chemical composition of tobacco smoke, which contains a host of toxic substances, including about 50 that can cause cancer. However, there has been relatively little research on the chemical composition of marijuana smoke.

In this new study, researchers compared marijuana smoke to tobacco smoke, using smoking machines to simulate the smoking habits of users. The scientists found that ammonia levels were 20 times higher in the marijuana smoke than in the tobacco smoke, while hydrogen cyanide, nitric oxide and certain aromatic amines occurred at levels 3-5 times higher in the marijuana smoke, they say. The finding is �important information for public health and communication of the risk related to exposure to such materials,� say the researchers. - MTS

Chemical Research in Toxicology: �A Comparison of Mainstream and Sidestream Marijuana and Tobacco Cigarette Smoke Produced under Two Machine Smoking Conditions� [PDF]

Existing biotechnology could save energy and cut CO2 by 100 percent

A new analysis has concluded that use of existing biotechnology in the production of so-called bulk chemicals could reduce consumption of non-renewable energy and carbon emissions by 100 percent. The study appeared in the Nov. 15 issue of ACS� Environmental Science & Technology, a semi-monthly journal.

Bulk chemicals like ethylene, butanol or acrylic acid are the basic raw materials used in the production of everything from plastics and fertilizers to electronic components and medicines. Currently derived from crude oil and natural gas, bulk chemical production creates billions of tons of carbon dioxide each year. Still, the application of industrial biotechnology for the production of bulk chemicals has received much less attention than alternative fuel or biomass-derived energy production.

B. G. Hermann and colleagues analyzed current and future technology routes leading to 15 bulk chemicals using industrial biotechnology, calculating their carbon emissions and fossil energy use. With biotechnology advances in the future, the researchers suggest that worldwide CO2 savings in the range of 500-1000 million tons per year are possible. Even today, bio-based bulk chemicals �offer clear savings in non-renewable energy use and green house gas emissions with current technology compared to conventional petrochemical production.� - AD

Environmental Science & Technology: �Producing Bio-Based Bulk Chemicals Using Industrial Biotechnology Saves Energy and Combats Climate Change� [PDF]

 Special edition�s �call to arms� on antioxidant research

Consumer demand for dietary supplements containing large amounts of plant-based antioxidants has outpaced scientific knowledge on the actual health benefits, best dosages, and risks of those phytochemicals, according to an editorial in the December (current) issue of ACS� Molecular Pharmaceutics, a bi-monthly journal. It is part of a special edition of the journal devoted to research on phytochemicals, substances found in fruits and vegetables, which show promise in preventing cancer, aging, heart disease and other conditions.

Guest Editor Ming Hu issues �a call to arms� for more relevant research on antioxidants, especially in the high doses used in dietary supplements. Many past studies on the potential health benefits of these compounds have been done in animals and their exact effects in humans are uncertain, he notes, without adequate attention to bioavailability - how much of a dose actually can be used by the body - and how phytochemicals interact with prescription drugs.

Hu calls for more studies exploring how these antioxidants are utilized in the body, particularly by targeted areas such as the heart and breast tissue. He notes, for example, that millions of women in the United States are taking soy-based phytoestrogens to relieve menopausal symptoms. Recent studies, however, found that a compound in soy might stimulate the growth of breast cancer. - MTS

Molecular Pharmaceutics: �Commentary: Bioavailability of Flavonoids and Polyphenols - Call to Arms� [PDF]

Toward improving the safety of Lithium-ion batteries

After recalls and fires involving Lithium-ion batteries, battery manufacturers and scientists have launched an intensive effort to improve the safety of these rechargeable power packs found in dozens of consumer electronics products, according to an article scheduled for the Dec. 17 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

In the article, C&EN Senior Editor Mitch Jacoby points out that fires and explosions involving Lithium-ion batteries are rare, occurring in anywhere from one in 1 million to one in 10 million batteries, according to the best estimates. Still, these widely-publicized incidents have worried consumers and forced costly recalls of millions of batteries.

Researchers in industry and academia do not fully understand why Lithium-ion batteries sometimes catch fire or explode, Jacoby notes. Possible explanations include impurities that short circuit the batteries and yet unidentified reactions that underlie the problem. Nevertheless, researchers are exploring new battery materials, including components that generate less heat and reduce the risk of mishaps. Manufacturers are already selling or planning to sell safer Lithium-ion batteries for power tools and electric vehicles, with more improvements on the way, according to the article.

Chemical & Engineering News: �Lithium-Ion Battery Safety�

�Golden bullet� shows promise for killing common parasite

Researchers in Australia report development of a new type of gold nanoparticle that destroys the parasite responsible for toxoplasmosis, a potentially serious disease acquired by handling the feces of infected cats or eating undercooked meat. Their so-called �golden bullet� could provide a safer, more effective alternative for treating the disease than conventional drug therapy, they say. The study is scheduled for the Dec. issue of ACS� Nano Letters, a monthly journal.

Toxoplasma gondii, the parasite that causes the disease, infects more than 60 million people in the United States alone. Although most infected people have no symptoms, it can cause serious health problems in pregnant women and individuals such as AIDS patients or organ transplant recipients who have weakened immune systems.

In the new study, Michael Cortie and colleagues attached antibodies to the parasite onto gold nanorods that are activated by laser-light. A group of Toxoplasma-infected animal cells were isolated in cell culture dishes and subsequently exposed to these �golden bullets.� The cells were then exposed to laser-light, which heated up the �bullets� and destroyed the parasites. The treatment killed about 83 percent of the parasites containing the gold particles, the researchers say. They hope to develop a similar technique for killing the parasite in patients.

Nano Letters: �A Golden Bullet" Selective Targeting of Toxoplasma gondii Tachyzoites Using Antibody-Functionalized Gold Nanorods� [PDF]

Solving another mystery of an amazing water walker

Walking on water may seem like a miracle to humans, but it is a ho-hum for the water strider and scientists who already solved the mystery of that amazing ability. Now researchers in Korea are reporting a long-sought explanation for the water strider�s baffling ability to leap onto a liquid surface without sinking. The study is scheduled for the Dec. 18 issue of ACS� Langmuir, a bi-weekly journal.

In the new study, Ho-Young Kim and Duck-Gyu Lee note that scientists already have discovered the hydrophobic, or water-repellent, structure of the water strider�s legs and how they allowed the creatures to scoot along ponds and placid lakes. However, their ability to jump onto or �bounce� off liquid surfaces remained a lingering scientific mystery.

Kim and Lee solved it by dropping a highly water-repellent sphere onto the surface of water at different speeds, carefully tracking its motion with high-speed cameras. They found that the ball must be traveling within a narrow velocity range in order to bounce off the water�s surface. The sphere may sink if it goes too fast and won�t bounce back if too slow. �The highly improved ability of heavy hydrophobic solids to keep afloat on water even after impacting upon water with a high velocity appears to explain partially why water striders have superhydrophobic legs,� say the authors. �Application of our study can be extended to developing semi-aquatic robots that mimic such insects having the surprising mobility on water.�

Langmuir: �Impact of a Superhydrophobic Sphere onto Water� [PDF]

Toward a Rosetta Stone for Microbes� Secret Language

Scientists are on the verge of decoding the special chemical language that bacteria use to �talk� to each other, British researchers report in a commentary article that appeared in the November issue of ACS Chemical Biology, a monthly journal. That achievement could lead to new treatments for antibiotic-resistant bacteria, including so-called superbugs that infect more than 90,000 people in the United States each year, they note.

David Spring, Martin Welch, and James T. Hodgkinson explain that researchers long have known that bacteria communicate with each other. Microbes release small molecules that enable millions of individuals in a population to coordinate their behavior. Disease-causing bacteria use this language to decide when to infect a person or other host. Decoding the structure and function of compounds involved in this elaborate signaling process, known as �quorum sensing,� could lead to new medicines to block the signals and prevent infections.

The report describes development of a group of powerful compounds, called N-acylated homoserine lactone (AHL) analogues that are effective against a broad-range of bacterial types, including those that cause diseases in humans. These compounds are �some of the most potent synthetic modulators of quorum sensing� identified to date, they say. In addition to showing promise for fighting antibiotic-resistant infections, the compounds may help prevent the growth of biofilms that foul medical implants and cause tooth decay and gum disease, the scientists note.

ACS Chemical Biology: �Learning the Language of Bacteria� [PDF]

Declining water levels in the Great Lakes may signal global warming

Researchers in Michigan report new evidence that water levels in the Great Lakes, which are near record low levels, may be shrinking due to global warming. Their study, which examines water level data for Lakes Michigan and Huron over more than a century, is scheduled for the Dec. 15 issue of ACS� Environmental Science & Technology, a semi-monthly journal.

In the new study, Craig Stow and colleagues point out that water levels in the Great Lakes, which supply drinking water to more than 40 million U.S. and Canadian residents, have fluctuated over thousands of years. But recent declines in water levels have raised concern because the declines are consistent with many climate change projections, they say.

To evaluate the factors behind this decline, the scientists examined water level data for Lakes Michigan and Huron from 1860 to 2006, including precipitation, evaporation and runoff data. The results reveal an underlying gradual decline in water levels since 1973. This underlying drop may be due to an increase in evaporation levels, they say.

�We cannot be certain that the present observed water level drop is caused by factors related to global climate change, or that it portends a long-term problem,� the study states. But the ongoing decline in water levels make it �prudent to include lower lake levels in future management planning,� the researchers note.

Environmental Science & Technology: �Recent Water Level Declines in the Lake Michigan�Huron System� [PDF]

New research promises personalized dietary guidelines

Better diets for fighting diabetes, obesity and heart disease may soon be only a finger-prick away. By analyzing the unique metabolic changes in an individual�s body, researchers hope to develop more personalized dietary guidelines for improving health, according to an article scheduled for the Dec. 10 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

In the article, C&EN Assistant Editor Carmen Drahl explains that not all people respond to diet in the same way: What makes some people healthy may in fact make others worse. Metabolomics, an emerging field whose practitioners study how foods affect metabolism, may provide new tools and data for customizing today�s one-size-fits-all dietary guidelines for an individual�s own body, the article notes. For example, a routine blood test that measures hundreds of compounds or more could detect shifts in a person�s metabolic balance to predict future health problems. Physicians then could develop a customized diet designed to work with that patient�s metabolism, while follow-up blood tests could allow caregivers to track improvements in a person�s health status, the article notes.

But the field is not quite ready for prime time. Academic and industry researchers alike are hard-at-work deciphering the complex science of how foods affect metabolism with the goal of building up a framework in which sound guidance for specifying personalized diet would become possible.

Chemical & Engineering News: �Science Diet�

First identification of blood on sculptures from ancient Kingdom of Mali

Scientists in France are reporting for the first time that sculptors from the fantastically wealthy ancient Empire of Mali - once the source of almost half the world�s gold - used blood to form the beautiful patina, or coating, on their works of art. In a study scheduled for the Dec. 15 issue of ACS� Analytical Chemistry, a semi-monthly journal, Pascale Richardin and colleagues describe development of a new, noninvasive test that accurately identifies traces of blood apparently left on ancient African artifacts used in ceremonies involving animal sacrifices.

Archaeologists often had reported or suspected the presence of blood on many African artifacts, the study points out. However, accurately identifying the presence of blood was difficult because of the tiny amounts of blood remaining over the ages.

The researchers describe use of three highly sensitive tests - time-of-flight secondary ion mass spectrometry, infrared microscopy, and X-ray microfluoresence - to identify iron-bound (the chemical fingerprint of blood) on the patina from seven Dogon and Bamana sculptures from Mali. The technique, which caused virtually no damage to priceless artworks, also is suitable for identification of blood on other ancient artifacts, the study states.

Analytical Chemistry: �Identification of Ritual Blood in African Artifacts using TOF-SIMS and Synchrotron Radiation Microspectroscopies� [PDF]

�Nanohybrid� plastic may expand use of biodegradable plastic

Scientists in New York are reporting development of a new biodegradable �nanohybrid� plastic that can be engineered to decompose much faster than existing plastics used in everything from soft drink bottles to medical implants. The study is scheduled for the Nov. issue of ACS� Biomacromolecules, a bi-monthly journal.

The plastic is a modified form of polyhydroxybutyrate (PHB), a promising biodegradable plastic produced from bacteria that has been widely hailed as a �green� alternative to petroleum-based plastic for use in packaging, agricultural and biomedical applications. Although commercially available since the 1980s, PHB has seen only limited use because of its brittleness and unpredictable biodegradation rates.

In the new study, Emmanuel P. Giannelis and colleagues compared the strength and biodegradation rates of raw PHB to a modified form of PHB that contains nanoparticles of clay or �nanoclays.� The scientists found that the modified PHB was stronger and decomposed faster than regular PHB. The nanohybrid PHB decomposed almost completely after seven weeks, while its traditional counterpart showed almost no decomposition. Researchers also showed that degradation could be fine-tuned by adjusting the amount of nanoparticles added.

The study is the �first report of the biodegradation of PHB nanocomposites� and could lead to wider use of PHB plastics, the scientists say.

Biomacromolecules: "New Biodegradable Polyhydroxybutyrate/Layered Silicate Nanocomposites" [PDF]

Bioprospectors identify hot new biofuel-producing bacteria

A bioprospecting expedition to Iceland�s famed hot springs has yielded new strains of bacteria with potential of producing hydrogen and ethanol fuels from wastewater now discharged from factories that process sugar beets, potatoes and other plant material. The microbes hold potential for combining energy production with wastewater treatment, according to a report on the discovery scheduled for the Jan./Feb. issue of ACS� Energy & Fuels, a bi-monthly journal.

In the study, Perttu E. P. Koskinen and colleagues point out that ethanol and hydrogen are two leading eco-friendly candidates for supplementing world supplies of oil, coal, and other conventional fuels. Research suggests that there would be advantages in producing those fuels by fermentation with bacteria capable of withstanding higher temperatures than microbes now in use.

Knowing that thermophilic, or heat-loving, bacteria inhabit Iceland�s hot springs, the scientists �bioprospected� scalding-hot geothermal springs in different parts of the country for new ethanol and hydrogen-producing bacteria. After screening samples, including those from springs that approached the boiling point of water, the scientists enriched promising microorganisms that can produce the compounds from glucose or cellulose at high temperatures. The enrichments included those with unusually high yields of hydrogen or ethanol from carbohydrates.

Energy & Fuels: �Bioprospecting Thermophilic Microorganisms from Icelandic Hot Springs for Hydrogen and Ethanol Production� [PDF]

Methanol shows increasing promise as an alternative fuel

After grabbing headlines for years as the ultimate solution to world energy problems, the �hydrogen economy� has an emerging but lesser-known competitor called the �methanol economy,� according to an article scheduled for the Dec. 3 issue of Chemical & Engineering News, ACS� weekly newsmagazine.

In the article, C&EN Associate Editor Jyllian Kemsley describes how methanol, an alcohol like ethanol, shows increasing promise as an alternative energy source with advantages over both ethanol and hydrogen. A methanol economy - championed in a 2006 book by chemistry Nobel Laureate George Olah - would not be dependent on bumper crops of corn and could provide lower tailpipe emissions and a reduced fire hazard. Besides powering automobile engines, methanol can also be used to power fuel cells and as a fuel for operating gas turbines at electric power plants, the article notes. It also can take the place of petroleum-based feedstocks for making a range of chemicals and materials, including plastics.

China now blazes the trail toward a methanol economy, putting 1 to 2 billion gallons per year toward fuel, according to the article. Researchers worldwide are now exploring new, more efficient methods for making methanol. One of the downsides of producing methanol, however, is that carbon dioxide, the primary gas behind climate change, is a byproduct. To remove that liability, scientists are also developing processes that can convert the carbon dioxide into more methanol or other usable materials, the article states.

Chemical & Engineering News: �Methanol's Allure�