Chemicals that eased one environmental problem may worsen another

Chemicals that helped solve a global environmental crisis in the 1990s - the hole in Earth's protective ozone layer - may be making another problem - acid rain - worse, scientists are reporting. Their study on the chemicals that replaced the ozone-destroying chlorofluorocarbons (CFCs) once used in aerosol spray cans, air conditioners, refrigerators, and other products, appears in ACS' Journal of Physical Chemistry A, a weekly publication.

Jeffrey Gaffney, Carrie J. Christiansen, Shakeel S. Dalal, Alexander M. Mebel and Joseph S. Francisco point out that hydrochlorofluorocarbons (HCFCs) emerged as CFC replacements because they do not damage the ozone layer. However, studies later suggested the need for a replacement for the replacements, showing that HCFCs act like super greenhouse gases, 4,500 times more potent than carbon dioxide. The new study adds to those concerns, raising the possibility that HCFCs may break down in the atmosphere to form oxalic acid, one of the culprits in acid rain.

They used a computer model to show how HCFCs could form oxalic acid via a series of chemical reactions high in the atmosphere. The model, they suggest, could have broader uses in helping to determine whether replacements for the replacements are as eco-friendly as they appear before manufacturers spend billions of dollars in marketing them.

Journal of Physical Chemistry A: "Hydroxyl Radical Substitution in Halogenated Carbonyls: Oxalic Acid Formation" [J. Phys. Chem. A, 2010, 114 (8), pp 2806–2820, DOI: 10.1021/jp9045116].

Evidence of increasing antibiotic resistance

A team of scientists in the United Kingdom and the Netherlands are reporting disturbing evidence that soil microbes have become progressively more resistant to antibiotics over the last 60 years. Surprisingly, this trend continues despite apparent more stringent rules on use of antibiotics in medicine and agriculture, and improved sewage treatment technology that broadly improves water quality in surrounding environments. Their report appears in ACS' bi-weekly journal Environmental Science and Technology.

David Graham and colleagues note that, although scientists have known for years that resistance was increasing in clinical situations, this is the first study to quantify the same problem in the natural environment over long time-scales. They express concern that increased antibiotic resistance in soils could have broad consequences to public health through potential exposure through water and food supplies. Their results "imply there may be a progressively increasing chance of encountering organisms in nature that are resistant to antimicrobial therapy."

The study involved an analysis of 18 different antibiotic resistance genes (ARGs) to four different classes of antibiotics in soil samples collected in the Netherlands from 1940 to 2008. ARGs are genes chosen to assess potential changes in resistance in microbes. Using data from sites around the Netherlands, the scientists found increasing levels in 78 percent of the ARG tested, clearly indicating increased potential for resistance over time. Because soil samples were only collected from the Netherlands, the scientists conclude their report by suggesting that further studies need be performed around the world so that the scope and possible ramifications of their results can be better understood.

Environmental Science and Technology: "Evidence of Increasing Antibiotic Resistance Gene Abundances in Archived Soils since 1940" [Environ. Sci. Technol., 2010, 44 (2), pp 580–587, DOI: 10.1021/es901221x].

Supermarket lighting enhances nutrient level of fresh spinach

Far from being a food spoiler, the fluorescent lighting in supermarkets actually can boost the nutritional value of fresh spinach, scientists are reporting. The finding could lead to improved ways of preserving and enhancing the nutritional value of spinach and perhaps other veggies, they suggest in a study in ACS' bi-weekly Journal of Agricultural and Food Chemistry.

Gene Lester, Donald J. Makus, and D. Mark Hodges note that fresh spinach is a nutritional powerhouse, packed with vitamin C, vitamin E, folate (a B vitamin), and healthful carotenoid antioxidants. Supermarkets often display fresh spinach in clear plastic containers at around 39 degrees Fahrenheit in showcases that may be exposed to fluorescent light 24 hours a day. Lester, Makus, and Hodges wondered how this continuous light exposure might affect spinach's nutritional value.

The scientists exposed fresh spinach leaves to continuous light or darkness during simulated retail storage conditions for three to nine days. Spinach stored in light for as little as three days had significantly higher levels of vitamins C, K, E, and folate. They also had higher levels of the healthful carotenoids (plant pigments) lutein and zeaxanthin. During continuous light exposure after nine days, levels of folate increased between 84 and 100 percent, for instance. Levels of vitamin K increased between 50 and 100 percent, depending on the spinach variety tested. By contrast, spinach leaves stored under continuous darkness tended to have declining or unchanged levels of nutrients, the scientists say.

Journal of Agricultural and Food Chemistry: "Relationship between Fresh-Packaged Spinach Leaves Exposed to Continuous Light or Dark and Bioactive Contents: Effects of Cultivar, Leaf Size, and Storage Duration" [J. Agric. Food Chem., 2010, 58 (5), pp 2980–2987, DOI: 10.1021/jf903596v].

Laser surgery technique gets new life in art restoration

A laser technique best known for its use to remove unwanted tattoos from the skin is finding a second life in preserving great sculptures, paintings and other works of art, according to an article in ACS' monthly journal, Accounts of Chemical Research. The technique, called laser ablation, involves removing material from a solid surface by vaporizing the material with a laser beam.

Salvatore Siano and Renzo Salimbeni point out that laser cleaning of artworks actually began about 10 years before the better known medical and industrial applications of the technique. Doctors, for example, use laser ablation in medicine to remove unwanted tattoos from the skin. In industry, the technique can remove paints, coatings and other material without damaging the underlying surface.

In the article, the scientists note that laser ablation has had an important impact in preserving the world's cultural heritage of great works of art. They describe the latest advances in laser cleaning of stone and metal statues and wall paintings, including masterpieces like Lorenzo Ghiberti's Porta del Paradiso and Donatello's David. They also discuss encouraging results of laser cleaning underwater for materials that could deteriorate if exposed to air.

Accounts of Chemical Research: "Advances in Laser Cleaning of Artwork and Objects of Historical Interest: The Optimized Pulse Duration Approach" [Acc. Chem. Res., Article ASAP, DOI: 10.1021/ar900190f].

An electrifying discovery: New material to harvest electricity from body movements

Scientists are reporting an advance toward scavenging energy from walking, breathing, and other natural body movements to power electronic devices like cell phones and heart pacemakers. In a study in ACS' monthly journal, Nano Letters, they describe development of flexible, biocompatible rubber films for use in implantable or wearable energy harvesting systems. The material could be used, for instance, to harvest energy from the motion of the lungs during breathing and use it to run pacemakers without the need for batteries that must be surgically replaced every few years.

Michael McAlpine and colleagues point out that popular hand-held consumer electronic devices are using smaller and smaller amounts of electricity. That opens the possibility of supplementing battery power with electricity harvested from body movements. So-called "piezoelectric" materials are the obvious candidates, since they generate electricity when flexed or subjected to pressure. However, manufacturing piezoelectric materials requires temperatures of more than 1,000 degrees F., making it difficult to combine them with rubber.

The scientists describe a new manufacturing method that solves this problem. It enabled them to apply nano-sized ribbons of lead zirconate titanate (PZT) - each strand about 1/50,000th the width of a human hair - to ribbons of flexible silicone rubber. PZT is one of the most efficient piezoelectric materials developed to date and can convert 80 percent of mechanical energy into electricity. The combination resulted in a super-thin film they call 'piezo-rubber' that seems to be an excellent candidate for scavenging energy from body movements.

Nano Letters: "Piezoelectric Ribbons Printed onto Rubber for Flexible Energy Conversion" [Nano Lett., 2010, 10 (2), pp 524–528, DOI: 10.1021/nl903377u].

Neutrons poised to play big role in future scientific advances

Subatomic particles called neutrons are poised to play a big role in fighting HIV, slowing global warming, and improving manufacturing processes. The reason: They are the focus of a process called neutron scattering that provides unprecedented ways to study the chemistry of a wide range of important materials, including coal and biological cells, according to a fascinating article in Chemical & Engineering News (C&EN), ACS' weekly newsmagazine.

C&EN Associate Editor Jyllian Kemsley notes that neutrons have properties useful for studying materials. Neutrons are special because they can penetrate deeper into samples than some other probes and can interact with atoms in ways that other particles can't. This gives scientists much more information about the structure and activity of materials than some current tools.

Using neutron scattering, scientists have studied how certain fluids behave under stress, which could lead to improved manufacturing processes and products. The method also has been used by scientists to study biological processes. All three of the neutron user facilities located at government labs in the United States are in various phases of expansion. "With greater knowledge of neutrons' capabilities and increased availability, scientific progress undoubtedly awaits," the article notes.

Chemical & Engineering News: "Making Use of Neutrons" [February 22, 2010 Volume 88, Number 8pp. 36-39].

New evidence that green tea may help fight glaucoma and other eye diseases

Scientists have confirmed that the healthful substances found in green tea - renowned for their powerful antioxidant and disease-fighting properties - do penetrate into tissues of the eye. Their new report, the first documenting how the lens, retina, and other eye tissues absorb these substances, raises the possibility that green tea may protect against glaucoma and other common eye diseases. It appears in ACS's bi-weekly Journal of Agricultural and Food Chemistry.

Chi Pui Pang and colleagues point out that so-called green tea "catechins" have been among a number of antioxidants thought capable of protecting the eye. Those include vitamin C, vitamin E, lutein, and zeaxanthin. Until now, however, nobody knew if the catechins in green tea actually passed from the stomach and gastrointestinal tract into the tissues of the eye.

Pang and his colleagues resolved that uncertainty in experiments with laboratory rats that drank green tea. Analysis of eye tissues showed beyond a doubt that eye structures absorbed significant amounts of individual catechins. The retina, for example, absorbed the highest levels of gallocatechin, while the aqueous humor tended to absorb epigallocatechin. The effects of green tea catechins in reducing harmful oxidative stress in the eye lasted for up to 20 hours. "Our results indicate that green tea consumption could benefit the eye against oxidative stress," the report concludes.

Journal of Agricultural and Food Chemistry: "Green Tea Catechins and Their Oxidative Protection in the Rat Eye" [J. Agric. Food Chem., 2010, 58 (3), pp 1523–1534, DOI: 10.1021/jf9032602].

Oil droplets can navigate complex maze

Call them oil droplets with a brain or even "chemo-rats." Scientists in Illinois have developed a way to make simple oil droplets "smart" enough to navigate through a complex maze almost like a trained lab rat. The finding could have a wide range of practical implications, including helping cancer drugs to reach their target and controlling the movement of futuristic nano-machines, the scientists say. Their study is in the weekly Journal of the American Chemical Society.

Bartosz Grzybowski and colleagues note that the ability to solve a maze is a common scientific test of intelligence. Animals ranging from rats to humans can master the task. Scientists would like to pass along that same ability to anti-cancer drugs, for instance, to help these medications navigate complex mazes of blood vessels and reach the tumor.

The scientists describe an advance in that direction. They developed postage-stamp-sized mazes, and infused them with an alkaline solution, and placed a gel containing a strong acid at the exit. That created a pH gradient, a difference between the acid-alkaline levels. Oil droplets containing a weak acid placed at the entrance of the mazes developed convective flows in response to pH differences and propelled themselves along the gradient toward the exit. Since cancer cells are more acidic than other body cells, the experiment may serve as a model for designing new anti-cancer drugs that move along similar acid-based gradients to target diseased cells, the scientists suggest.

Journal of the American Chemical Society: "Maze Solving by Chemotactic Droplets" [J. Am. Chem. Soc., 2010, 132 (4), pp 1198–1199, DOI: 10.1021/ja9076793].

Answering that age-old lament: Where does all this dust come from?

Where does it come from? Scientists in Arizona are reporting a surprising answer to that question, which has puzzled and perplexed generations of men and women confronted with layers of dust on furniture and floors. Most of indoor dust comes from outdoors. Their report appears in the ACS' Environmental Science & Technology, a semi-monthly journal.

In the study, David Layton and Paloma Beamer point out that household dust consists of a potpourri that includes dead skin shed by people, fibers from carpets and upholstered furniture, and tracked-in soil and airborne particles blown in from outdoors. It can include lead, arsenic and other potentially harmful substances that migrate indoors from outside air and soil. That can be a special concern for children, who consume those substances by putting dust-contaminated toys and other objects into their mouths.

The scientists describe development and use on homes in the Midwest of a computer model that can track distribution of contaminated soil and airborne particulates into residences from outdoors. They found that over 60 percent of house dust originates outdoors. They estimated that nearly 60 percent of the arsenic in floor dust could come from arsenic in the surrounding air, with the remainder derived from tracked-in soil. The researchers point out the model could be used to evaluate methods for reducing contaminants in dust and associated human exposures.

Environmental Science & Technology: "Migration of Contaminated Soil and Airborne Particulates to Indoor Dust" [Environ. Sci. Technol., 2009, 43 (21), pp 8199–8205, DOI: 10.1021/es9003735].

Stitching together 'lab-on-a-chip' devices with cotton thread and sewing needles

Scientists in Australia are reporting the first use of ordinary cotton thread and sewing needles to literally stitch together a microfluidic analytical device - microscopic technology that can transport fluids for medical tests and other purposes in a lab-on-a-chip. The chips shrink room-sized diagnostic testing equipment down to the size of a postage stamp, and promise revolutionary applications in medicine, environmental sensing, and other areas. Their study is in ACS Applied Materials & Interfaces, a monthly journal.

Wei Shen and colleagues note that the development of low-cost "lab-on-a-chip" diagnostic tests has become an attractive area of research. Existing devices require etching microscopic channels onto slivers of silicon, glass, ceramics, or metal in a costly, complicated process. The scientists set out to find an alternative, and did so with cotton thread, which wicks fluids along its tiny fibers.

They stitched thread into paper to form microfluidic sensors capable of detecting and measuring substances released in the urine of patients with several human medical conditions. "The fabrication of thread-based microfluidic devices is simple and relatively low cost because it requires only sewing needles or household sewing machines," the report said. "Our results demonstrate that thread is a suitable material for fabricating microfluidic diagnostic devices for monitoring human health, environment and food safety, especially for the population in less-industrialized areas or remote regions."

Applied Materials & Interfaces: "Thread as a Versatile Material for Low-Cost Microfluidic Diagnostics" [ppl. Mater. Interfaces, 2010, 2 (1), pp 1–6; DOI: 10.1021/am9006148].

Transforming skin cells into stem cells using a molecular toolkit

In an effort to sidestep the ethical dilemma involved in using human embryonic stem cells to treat diseases, scientists are developing non-controversial alternatives: In particular, they are looking for drug-like chemical compounds that can transform adult skin cells into the stem cells now obtained from human embryos. That's the topic of a fascinating article in Chemical & Engineering News (C&EN), ACS' weekly newsmagazine.

C&EN Associate Editor Sarah Everts notes that in 2006, researchers in Japan figured out a way to use genetic engineering to coax a skin cell to become a so-called "pluripotent" stem cell - a type of cell that can potentially morph or change into any cell of the human body. The scientists achieved the result by infecting the skin cell with a virus containing certain genes instructing the cell to change.

Now chemists are trying to reproduce this cellular alchemy with drug-like substances because gene therapies have faced trouble getting into the clinic. Scientists are looking for chemical ways to go backward in cell development - to reprogram mature cells into stem cells. Others are trying to identify substances that can morph one cell directly into other cell types - for example, from a skin cell directly into a nerve cell that might treat Parkinson's disease - without the use of stem cells at all. The ultimate goal is to be able to reprogram any cell of the body into another by means of a simple molecular kit, the article notes. But as chemists start putting together toolkits with these drug-like molecules, they face many technical hurdles as well as challenges getting acceptance from the stem cell community.

Chemical & Engineering News: "Back to the future with stem cells" [Volume 88, Number 6pp. 50 - 53, February 8, 2010 ].

Extra large carbon

Heaviest halo nucleus discovered.

An exotic form of carbon has been found to have an extra large nucleus, dwarfing even the nuclei of much heavier elements like copper and zinc, in experiments performed in a particle accelerator in Japan. The discovery is reported in the current issue of Physical Review Letters and highlighted with a Viewpoint by Kirby Kemper and Paul Cottle of Florida State University in the February 8 issue of Physics.

Carbon-22, which has a nucleus comprised of 16 neutrons and 6 protons, is the heaviest atom yet discovered to exhibit a "halo nucleus." In such atoms, some of the particles that normally reside inside the nucleus move into orbits outside the nucleus, forming a halo of subatomic particles. Because atoms like carbon-22 are packed with an excessive number of neutrons, they're unstable and rapidly break apart to form lighter atoms, but they are more stable than scientists had previously expected. The extra stability is a surprise because the three particles-– two neutrons and a nucleus-– that form a halo nucleus interact in a way that is difficult for physicists to model due to the complicated mathematics necessary to describe so-called "three body" problems.

The unexpected stability has led to such halo nucleus atoms being labeled Borromean atoms in reference to an ancient pattern depicting three rings interlocked such that the removal of any one ring would cause all three to be disconnected. Borromean rings were often used to symbolize a stable union of three parts in traditional carvings and family crests.

The detection and analysis of carbon-22 sets a new milestone in challenging nuclear physics, and hails a promising era in the investigation of heavier and even more exotic nuclei as new beam facilities and more sensitive detectors come on line over the next decade. The surprising discovery of carbon-22's halo suggests that nuclear physicists will have plenty of new ground to cover in coming years.

[Kirby W. Kemper and Paul D. Cottle: A breakthrough observation for neutron dripline physics. Physics, 3, 13, February 8, 2010; DOI 10.1103/Physics.3.13]

First discovery of the female sex hormone progesterone in a plant

In a finding that overturns conventional wisdom, scientists are reporting the first discovery of the female sex hormone progesterone in a plant. Until now, scientists thought that only animals could make progesterone. A steroid hormone secreted by the ovaries, progesterone prepares the uterus for pregnancy and maintains pregnancy. A synthetic version, progestin, is used in birth control pills and other medications. The discovery is reported in the American Chemical Society's Journal of Natural Products, a monthly publication.

"The significance of the unequivocal identification of progesterone cannot be overstated," the article by Guido F. Pauli and colleagues, states. "While the biological role of progesterone has been extensively studied in mammals, the reason for its presence in plants is less apparent." They speculate that the hormone, like other steroid hormones, might be an ancient bioregulator that evolved billions of years ago, before the appearance of modern plants and animals. The new discovery may change scientific understanding of the evolution and function of progesterone in living things.

Scientists previously identified progesterone-like substances in plants and speculated that the hormone itself could exist in plants. But researchers had not found the actual hormone in plants until now. Pauli and colleagues used two powerful laboratory techniques, nuclear magnetic resonance and mass spectroscopy, to detect progesterone in leaves of the Common Walnut, or English Walnut, tree. They also identified five new progesterone-related steroids in a plant belonging to the buttercup family.

Journal of Natural Products: "Occurrence of Progesterone and Related Animal Steroids in Two Higher Plants" [J. Nat. Prod., January 28, 2010; DOI: 10.1021/np9007415].

Toward safer plastics that lock in potentially harmful plasticizers

Scientists have published the first report on a new way of preventing potentially harmful plasticizers - the source of long-standing human health concerns - from migrating from one of the most widely used groups of plastics. The advance could lead to a new generation of polyvinyl chloride (PVC) plastics that are safer than those now used in packaging, medical tubing, toys, and other products, they say. Their study is in ACS' Macromolecules, a bi-weekly journal.

Helmut Reinecke and colleagues note that manufacturers add large amounts of plasticizers to PVC to make it flexible and durable. Plasticizers may account for more than one-third of the weight of some PVC products. Phthalates are the mainstay plasticizers. Unfortunately, they migrate to the surface of the plastic over time and escape into the environment. As a result, PVC plastics become less flexible and durable. In addition, people who come into contact with the plastics face possible health risks. The U. S. Consumer Product Safety Commission in 2009 banned use of several phthalate plasticizers for use in manufacture of toys and child care articles.

The scientists describe development of a way to make phthalate permanently bond, or chemically attach to, the internal structure of PVC so that it will not migrate. Laboratory tests showed that the method completely suppressed the migration of plasticizer to the surface of the plastic. "This approach may open new ways to the preparation of flexible PVC with permanent plasticizer effect and zero migration," the article notes.

Macromolecules: "Phthalate Plasticizers Covalently Bound to PVC: Plasticization with Suppressed Migration" [Article ASAP; DOI: 10.1021/ma902740t].

Imaging method for eye disease used to eye art forgeries

Scientists in Poland are describing how a medical imaging technique has taken on a second life in revealing forgery of an artist's signature and changes in inscriptions on paintings that are hundreds of years old. A report on the technique, called optical coherence tomography (OCT), is in ACS' Accounts of Chemical Research, a monthly journal.

Piotr Targowski notes that easel paintings prepared according to traditional techniques consist of multiple layers. The artist, for instance, first applies a glue sizing over the canvas to ensure proper adhesion of later layers. Those layers may include an outline of the painting, the painting itself, layers of semitransparent glazes, and finally transparent varnish. Art conservators and other experts resort to a variety of technologies to see below the surface and detect changes, including forged signatures and other alterations in a painting. But those approaches may damage artistic treasures or not be sensitive enough to detect finer details.

The scientists describe how OCT, used to produce three-dimensional images of the layers of the retina of the eye, overcomes those difficulties. They used OCT to analyze two oil paintings from the 18th and 19th centuries. In one, "Saint Leonard of Porto Maurizio," OCT revealed evidence that the inscription "St. Leonard" was added approximately fifty years after completion of the painting. In the other, "Portrait of an unknown woman," OCT found evidence of the possible of forgery of the artist's signature.

Accounts of Chemical Research: "Structural Examination of Easel Paintings with Optical Coherence Tomography" [Acc. Chem. Res., Article ASAP; DOI: 10.1021/ar900195d].

Enlisting a drug discovery technique in the battle against global warming

Scientists in Texas are reporting that a technique used in the search for new drugs could also be used in the quest to discover new, environmentally friendly materials for fighting global warming. Such materials could be used to capture the greenhouse gas carbon dioxide from industrial smokestacks and other fixed sources before it enters the biosphere. The new study appears in ACS' bi-monthly journal Energy & Fuels.

Michael Drummond and colleagues Angela Wilson and Tom Cundari note that greener carbon-capture technologies are a crucial component in mitigating climate change. Existing technology is expensive and can generate hazardous waste. They point out that proteins, however, can catalyze reactions with carbon dioxide, the main greenhouse gas, in an environmentally friendly way. That fact got the scientists interested in evaluating the possibility of using proteins in carbon capture technology.

In the study, they used the pharmacophore concept to probe how the 3-dimensional structure of proteins affects their ability to bind and capture carbon dioxide. The German chemist and Nobel Laureate Paul Ehrlich, who originated the concept a century ago, defined a pharmacophore as the molecular framework that carries the key features responsible for a drug's activity. The scientists concluded that the approach could point the way to the development of next-generation carbon capture technologies.

Energy & Fuels: "Toward Greener Carbon Capture Technologies: A Pharmacore-Based Approach to Predict CO2 Binding Sites in Proteins" [Article ASAP; DOI: 10.1021/ef901132v].

Older dental fillings contain form of mercury unlikely to be toxic

A new study on the surface chemistry of silver-colored, mercury-based dental fillings suggests that the surface forms of mercury may be less toxic than previously thought. It appears online in ACS' journal Chemical Research in Toxicology.

In the study, Graham George and colleagues note that mercury-based fillings, also called amalgams, have been used by dentists to repair teeth for well-over a century. In recent decades their use has become controversial because of concerns about exposure to potentially toxic mercury. However, mercury can potentially exist in several different chemical forms, each with a different toxicity. Prior to this report, little was known about how the chemical forms of mercury in dental amalgam might change over time.

Using a special X-ray technique, the scientists analyzed the surface of freshly prepared metal fillings and compared these with the surface of aged fillings (about 20 years old) from a dental clinic. Fresh fillings contained metallic mercury, which can be toxic. Aged fillings, however, typically contain a form of mercury, called beta-mercuric sulfide or metacinnabar, which is unlikely to be toxic in the body. The scientists found that the surfaces of metal fillings seem to lose up to 95 percent of their mercury over time. Loss of potentially toxic mercury from amalgam may be due to evaporation, exposure to some kinds of dental hygiene products, exposure to certain foods, or other factors. The scientists caution that "human exposure to mercury lost from fillings is still of concern."

Chemical Research in Toxicology: "The Chemical Forms of Mercury in Aged and Fresh Dental Amalgam Surfaces" [Chem. Res. Toxicol., 2009, 22 (11), pp 1761–1764; DOI: 10.1021/tx900309c].

Ginkgo herbal medicines may increase seizures in people with epilepsy

Restrictions should be placed on the use of Ginkgo biloba (G. biloba) - a top-selling herbal remedy - because of growing scientific evidence that Ginkgo may increase the risk of seizures in people with epilepsy and could reduce the effectiveness of anti-seizure drugs, a new report concludes. The article appears in ACS' monthly Journal of Natural Products. It also suggests that Ginkgo may have harmful effects in other people after eating raw or roasted Ginkgo seed or drinking tea prepared from Ginkgo leaves.

Eckhard Leistner and Christel Drewke note that consumers use pills, teas, and other products prepared from leaves of the Ginkgo tree to treat a wide array of health problems. Those include Alzheimer's disease and other memory loss, clinical depression, headache, irritable bladder, alcohol abuse, blockages in blood vessels, poor concentration, and dizziness. Scientific concern focuses mainly on one chemical compound in the herb. It is a potentially toxic material known as ginkgotoxin.

They reviewed scientific research on Ginkgo, and found 10 reports indicating that patients with epilepsy who take Ginkgo products face an increased risk of seizures. They note that laboratory studies explain how Ginkgo could have that unwanted effect. Ginkgotoxin seems to alter a chemical signaling pathway in ways that may trigger epileptic seizures. Further evidence showed that Ginkgo can interact with anti-seizure medications and reduce their effectiveness. "Contrary to our own previous assumption, we are now convinced, however, that G. biloba medications and other products can have a detrimental effect on a person's health condition," the report concludes. "It is therefore important that the large number of G. biloba product users and their health care providers be made aware of these risks, in order to enable them to make informed decisions about the use of these preparations."

Journal of Natural Products: "Ginkgo biloba and Ginkgotoxin" [J. Nat. Prod., 2010, 73 (1), pp 86–92; DOI: 10.1021/np9005019].

The secret life of smoke in fostering rebirth and renewal of burned landscape

The innermost secrets of fire's role in the rebirth and renewal of forests and grasslands are being revealed in research that has identified plant growth promoters and inhibitors in smoke. In the latest discovery about smoke's secret life, an international team of scientists are reporting discovery of a plant growth inhibitor in smoke. The study appears in ACS's Journal of Natural Products, a monthly publication.

"Smoke plays an intriguing role in promoting the germination of seeds of many species following a fire," Johannes Van Staden and colleagues point out in the report. They previously discovered a chemical compound in smoke from burning plants that promotes seed germination. Such seeds, which remain in the undercover on forest and meadow floors after fires have been extinguished, are responsible for the surprisingly rapid regrowth of fire-devastated landscapes.

In their new research, the scientists report discovery of an inhibitor compound that may block the action of the stimulator, preventing germination of seeds. They suspect that the compounds may be part of a carefully crafted natural regulatory system for repopulating fire-ravaged landscapes. Interaction of these and other compounds may ensure that seeds remain dormant until environmental conditions are best for germination. The inhibitor thus may delay germination of seeds until moisture and temperature are right, and then take a back seat to the germination promoter in smoke.

Journal of Natural Products: "Butenolides from Plant-Derived Smoke: Natural Plant-Growth Regulators with Antagonistic Actions on Seed Germination" [J. Nat. Prod., Article ASAP; DOI: 10.1021/np900630w].

The fungus among us: An eco-friendly way of decomposing BPA-containing plastic

Just as cooking helps people digest food, pretreating polycarbonate plastic - source of a huge environmental headache because of its bisphenol A (BPA) content - may be the key to disposing of the waste in an eco-friendly way, scientists have found. Their new study is in ACS' Biomacromolecules, a monthly journal.

Mukesh Doble and Trishul Artham note that manufacturers produce about 2.7 million tons of plastic containing BPA each year. Polycarbonate is an extremely recalcitrant plastic, used in everything from screwdriver handles to eyeglass lenses, DVDs, and CDs. Some studies have suggested that the BPA may have a range of adverse health effects, sparking the search for an environmentally safe way of disposing of waste plastic to avoid release of BPA.

The scientists pretreated polycarbonate with ultraviolet light and heat and exposed it to three kinds of fungi - including the fabled white-rot fungus, used commercially for environmental remediation of the toughest pollutants. The scientists found that fungi grew better on pretreated plastic, using its BPA and other ingredients as a source of energy and breaking down the plastic. After 12 months, there was almost no decomposition of the untreated plastic, compared to substantial decomposition of the pretreated plastic, with no release of BPA.

Biomacromolecules: "Biodegradation of Physiochemically Treated Polycarbonate by Fungi" [2010, 11 (1), pp 20–28; DOI: 10.1021/bm9008099].

Consumers over age 50 should consider steps to cut copper and iron intake

With scientific evidence linking high levels of copper and iron to Alzheimer's disease, heart disease, and other age-related disorders, a new report in ACS' Chemical Research in Toxicology suggests specific steps that older consumers can take to avoid build up of unhealthy amounts of these metals in their bodies. "This story of copper and iron toxicity, which I think is reaching the level of public health significance, is virtually unknown to the general medical community, to say nothing of complete unawareness of the public," George Brewer states in the report.

The article points out that copper and iron are essential nutrients for life, with high levels actually beneficial to the reproductive health of younger people. After age 50, however, high levels of these metals can damage cells in ways that may contribute to a range of age-related diseases.

"It seems clear that large segments of the population are at risk for toxicities from free copper and free iron, and to me, it seems clear that preventive steps should begin now." The article details those steps for people over age 50, including avoiding vitamin and mineral pills that contain cooper and iron; lowering meat intake: avoiding drinking water from copper pipes; donating blood regularly to reduce iron levels; and taking zinc supplements to lower copper levels.

Chemical Research in Toxicology: "Risks of Copper and Iron Toxicity during Aging in Humans" [Chem. Res. Toxicol., Article ASAP; December 7, 2009; DOI: 10.1021/tx900338d].

First evidence that blueberry juice improves memory in older adults

Scientists are reporting the first evidence from human research that blueberries - one of the richest sources of healthful antioxidants and other so-called phytochemicals - improve memory. They said the study establishes a basis for comprehensive human clinical trials to determine whether blueberries really deserve their growing reputation as a memory enhancer. A report on the study appears in ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Robert Krikorian and colleagues point out that previous studies in laboratory animals suggest that eating blueberries may help boost memory in the aged. Until now, however, there had been little scientific work aimed at testing the effect of blueberry supplementation on memory in people.

In the study, one group of volunteers in their 70s with early memory decline drank the equivalent of 2-2 l/2 cups of a commercially available blueberry juice every day for two months. A control group drank a beverage without blueberry juice. The blueberry juice group showed significant improvement on learning and memory tests, the scientists say. "These preliminary memory findings are encouraging and suggest that consistent supplementation with blueberries may offer an approach to forestall or mitigate neurodegeneration," said the report. The research involved scientists from the University of Cincinnati, the U.S. Department of Agriculture, and the Canadian department of agriculture.

Journal of Agricultural and Food Chemistry: "Blueberry Supplementation Improves Memory in Older Adults" [J. Agric. Food Chem., Article ASAP, January 4, 2010; DOI: 10.1021/jf9029332].

An electrifying advance toward tomorrow's power suits

Could powering an iPod or cell phone become as easy as plugging it into your tee shirt or jeans, and then recharging the clothing overnight? Scientists in California are reporting an advance in that direction with an easier way of changing ordinary cotton and polyester into "conductive energy textiles" - e-Textiles that double as a rechargeable battery. Their report on the research appears in ACS' Nano Letters, a monthly journal.

"Wearable electronics represent a developing new class of materials with an array of novel functionalities, such as flexibility, stretchability, and lightweight, which allow for many applications and designs previously impossible with traditional electronics technology," Yi Cui and colleagues note. "High-performance sportswear, wearable displays, new classes of portable power, and embedded health monitoring systems are examples of these novel applications."

The report describes a new process for making E-textiles that uses "ink" made from single-walled carbon nanotubes - electrically conductive carbon fibers barely 1/50,000 the width of a human hair. When applied to cotton and polyester fabrics, the ink produced e-Textiles with an excellent ability to store electricity. The fabrics retained flexibility and stretchability of regular cotton and polyester, and kept their new e-properties under conditions that simulated repeated laundering.

Nano Letters: "Stretchable, Porous, and Conductive Energy Textiles" [Nano Lett., Article ASAP; January 5, 2010; DOI: 10.1021/nl903949m].

School classroom air may be more polluted with ultrafine particles than outdoor air

The air in some school classrooms may contain higher levels of extremely small particles of pollutants - easily inhaled deep into the lungs - than polluted outdoor air, scientists in Australia and Germany are reporting in an article in ACS' semi-monthly journal Environmental Science & Technology.

Lidia Morawska and colleagues note increasing concern in recent years over the health effects of airborne ultrafine particles. Evidence suggests that they can be toxic when inhaled into the lungs. Much of the scientific research, however, has focused on outdoor sources of these invisible particles, particularly vehicle emissions. Little research has been done, however, on indoor sources, and even less on ultrafine particles in school classrooms.

In an effort to fill those gaps in knowledge, the scientists studied levels of ultrafine particles in 3 elementary school classrooms in Brisbane, Australia. They found that on numerous occasions ultrafine particle levels in the classrooms were significantly higher than outdoors. The highest levels occurred during art activities such as gluing, painting and drawing when indoor levels were several times higher than outdoor levels. There also were significant increases in ultrafine particle levels when detergents were used for cleaning.

Environmental Science & Technology: "Ultrafine Particles in Indoor Air of a School: Possible Role of Secondary Organic Aerosols" [Environ. Sci. Technol., 2009, 43 (24), pp 9103–9109; DOI: 10.1021/es902471a].

Toward a less expensive version of the anti-flu drug Tamiflu

Scientists have developed an alternative method for producing the active ingredient in Tamiflu®, the mainstay for fighting H1N1 and other forms of influenza. The new process could expand availability of the drug by reducing its cost, which now retails for as about $8 per dose. Their study is in ACS' Organic Letters, a bi-weekly journal.

Anqi Chen, Christina Chai and colleagues note that the global pandemic of H1N1 has resulted in millions of infected cases worldwide and nearly 10,000 deaths to date. Tamiflu®, also known as oseltamivir phosphate, remains the most widely used antiviral drug for the prevention and treatment of H1N1 infections as well as bird flu and seasonal influenzas. But growing demand for the drug has put pressure on the supply of shikimic acid, the raw material now used in making the drug. "As a result, chemists worldwide including ourselves have explored the possibility of using other alternative raw materials for the synthesis of the drug" said Chen and Chai, who led the research.

The scientists describe a new process for making the drug that does not use shikimic acid. They found that D-ribose, a naturally-occurring sugar produced by fermentation in large scales, potentially provides an inexpensive and abundant source of starting material for making the drug. D-ribose costs only about one-sixth as much as shikimic acid. In lab studies, the scientists demonstrated the potential use of D-ribose as an alternative source for the synthesis of Tamiflu®.

Organic Letters: "Efficient Formal Synthesis of Oseltamivir Phosphate (Tamiflu) with Inexpensive D-Ribose as the Starting Material" [Org. Lett., 2010, 12 (1), pp 60–63; DOI: 10.1021/ol9024716].

Unlocking the mystery of the duck-billed platypus' venom

Abandon any notion that the duck-billed platypus is a soft and cuddly creature - maybe like Perry the Platypus in the Phineas and Ferb cartoon. This platypus, renowned as one of the few mammals that lay eggs, also is one of only a few venomous mammals. The males can deliver a mega-sting that causes immediate, excruciating pain, like hundreds of hornet stings, leaving victims incapacitated for weeks. Now scientists are reporting an advance toward deciphering the chemical composition of the venom, with the first identification of a dozen protein building blocks. Their study is in the Journal of the American Chemical Society, a weekly publication.

Masaki Kita, Daisuke Uemura, and colleagues note that spurs in the hind limb of the male platypus can deliver the venom, a cocktail of substances that cause excruciating pain. The scientists previously showed that the venom triggers certain chemical changes in cultured human nerve cells that can lead to the sensation of pain. Until now, however, scientists did not know the exact components of the venom responsible for this effect.

To unlock its secrets, the scientists collected samples of platypus venom and used high-tech analytical instruments to separate and characterize its components. They identified 11 new peptides, or protein subunits, in the venom. Studies using nerve cells suggest that one of these substances, called Heptapeptide 1, is the main agent responsible for triggering pain. The substance appears to work by interacting with certain receptors in the nerve cells, they suggest.

Journal of the American Chemical Society: "Duck-Billed Platypus Venom Peptides Induce Ca²⁺ Influx in Neuroblastoma Cells" [J. Am. Chem. Soc., 2009, 131 (50), pp 18038–18039; DOI: 10.1021/ja908148z].

New biomarkers for predicting the spread of colon cancer

Scientists in China are reporting discovery of two proteins present in the blood, of people with colon cancer that may serve as the potential biomarkers for accurately predicting whether the disease will spread. Their study is in ACS' Journal of Proteome Research, a monthly publication.

Maode Lai and colleagues note that in 2008, 150,000 new cases of colon cancer and over 50,000 deaths from the disease occurred in the United States alone. Surgery is the main method of treating the disease. However, half of colon cancer patients undergoing surgery develop a recurrence of the disease within 5 years due to its spread, or metastasis, to other parts of the body. The spread of colon cancer can be difficult to detect and there are currently no reliable chemical markers in the body for predicting its spread, the scientists say.

In an effort to identify useful biomarkers for tracking the spread of colon cancer, the scientists compared proteins produced by primary, or original, tumor cells to those of metastasized cells came from a single individual with colon cancer. They identified two proteins that occurred at significantly higher levels in the metastatic cells than in the primary cancer cells. The two proteins could serve as potential biomarkers in a blood test for predicting the spread of colon cancer, allowing earlier intervention and treatment, the scientists say.

Journal of Proteome Research: "Identification of serum biomarkers for colorectal cancer metastasis using a differential secretome approach" [J. Proteome Res., 2010, 9 (1), pp 545–555; DOI: 10.1021/pr9008817].

China stakes claim as global center for scientific research

Contrary to popular belief, China is doing much more than exporting clothing, toys, electronics, and other popular consumer goods. The country is on a scientific roll, to the point where it could conceivably be regarded as the emerging global center for scientific research, a new report indicates. It describes an amazing growth in chemical patenting and publishing that could bring new and innovative products to the world market ranging from pharmaceuticals to microchips, according to an article in the current issue of Chemical & Engineering News, (C&EN) ACS' weekly newsmagazine.

C&EN Senior Editor Sophie L. Rovner reports that China in 2009 became the world leader in the number of chemistry patent applications published annually. China published 67,000 patent applications in 2009, compared to 52,000 for Japan and 41,000 for the United States. Publication of scientific papers originating in China increased faster than any other nation during the last 10 years. The output of papers with Chinese authors more than quadrupled - from 20,000 papers in 1998 to more than 112,000 in 2008. The publication of U.S. scientific papers rose by barely 30 percent during that period.

In achieving this growth, scientists in China are embracing collaborators in the U.S. and other countries. It is becoming increasingly clear that the country is changing the "world map of research," with China conceivably at its center, the article suggests.

Chemical & Engineering News: "China Ascendant" [Volume 88, Number 2pp. 35-37].

'Nanodragster' races toward the future of molecular machines

Scientists in Texas are reporting the development of a "nanodragster" that may speed the course toward development of a new generation of futuristic molecular machines. The vehicle - only 1/50,000th the width of a human hair - resembles a hot-rod in shape and can outperform previous nano-sized vehicles. Their report is in ACS' Organic Letters, a bi-weekly journal.

James Tour, Kevin Kelly and colleagues note that the ability to control the motion of small molecules is essential for building much-anticipated molecular machines. Some of these machines may find use in manufacturing computer circuits and other electronic components in the future. Scientists have already made strides by designing nano-sized vehicles, including a "nanocar" with wheels made of buckyballs - spheres of carbon containing 60 atoms apiece. The car can scoot around a gold surface when exposed to heat or an electric field gradient. But control of its movement is limited. These drawbacks prevent its widespread use. But the most limiting factor is the nanoscopic resolution tools available for studying their range of motions and capabilities.

The new vehicle addresses some of these problems. The front end has a smaller axle and wheels made of special materials that roll easier. The rear wheels sport a longer axle but are still made of buckyballs, which provide strong surface grip. These changes result in a "nanodragster" that can operate at lower temperatures than a regular nanocar and possibly has has better agility, paving the way for better molecular machines, the scientists say.

Organic Letters: "Molecular Machinery: Synthesis of a Nanodragster" [Org. Lett., 2009, 11 (24), pp 5602–5605; DOI: 10.1021/ol902312m].

Nitric oxide-releasing wrap for donor organs and cloth for therapeutic socks

Scientists in Texas are reporting development of a first-of-its-kind cloth that releases nitric oxide gas - an advance toward making therapeutic socks for people with diabetes and a wrap to help preserve organs harvested for transplantation. The study is in ACS' Chemistry of Materials, a bi-weekly journal.

Kenneth Balkus and Harvey Liu note in the new study that nitric oxide (NO) helps increase blood flow and regulates a range of other body functions. Scientists have tried for years to find practical ways to store and deliver NO for use in medicine. However, they have had difficulty finding a suitable material that allows controlled delivery of NO. Recent studies suggested that zeolites could work. These porous materials soak up and store large amounts of gases like NO.

The scientists describe development of a new bandage composed of nitric oxide-absorbing zeolites embedded in a special water-repellant polymer. In experiments with laboratory rats, the bandage slowly released nitric oxide and increased blood flow. "The bandage could be used to wrap a donor organ ensuring intimate contact and direct delivery of nitric oxide," the report states. "Additionally, these interwoven fabrics could also find applications in smart textiles such as NO-releasing socks for diabetic patients, who have been shown to produce less nitric oxide than healthy patients."

Chemistry of Materials: "Novel Delivery System for the Bioregulatory Agent Nitric Oxide" [Chem. Mater., 2009, 21 (21), pp 5032–5041; DOI: 10.1021/cm901358z].

Coal from mass extinction era linked to lung cancer mystery

The volcanic eruptions thought responsible for Earth's largest mass extinction - which killed more than 70 percent of plants and animals 250 million years ago - is still taking lives today. That's the conclusion of a new study showing, for the first time, that the high silica content of coal in one region of China may be interacting with volatile substances in the coal to cause unusually high rates of lung cancer. The study, which helps solve this cancer mystery, appears in ACS' Environmental Science & Technology, a semi-monthly publication.

David Large and colleagues note that parts of China's Xuan Wei County in Yunnan Province have the world's highest incidence of lung cancer in nonsmoking women - 20 times higher than the rest of China. Women in the region heat their homes and cook on open coal-burning stoves that are not vented to the outside. Scientists believe that indoor emissions from burning coal cause cancer, but are unclear why the lung cancer rates in this region are so much higher than other areas. Earlier studies show a strong link between certain volatile substances, called PAHs, in coal smoke and lung cancer in the region.

The scientists found that coal used in parts of Xuan Wei County had about 10 times more silica, a suspected carcinogen, than U.S. coal. Silica may work in conjunction with PAHs to make the coal more carcinogenic, they indicate. The scientists also found that this high-silica coal was formed 250 million years ago, at a time when massive volcanic eruptions worked to deposit silica in the peat that formed Xuan Wei's coal.

Environmental Science & Technology: "Silica-Volatile Interaction and the Geological Cause of the Xuan Wei Lung Cancer Epidemic" [Environ. Sci. Technol., 2009, 43 (23), pp 9016–9021; DOI: 10.1021/es902033j].

More evidence on benefits of high blood pressure drugs in diabetic eye disease

Scientists in Massachusetts are reporting new evidence that certain high blood pressure drugs may be useful in preventing and treating diabetic retinopathy, the leading cause of vision loss in people with diabetes. The study, the largest to date on proteins in the retina, could lead to new ways to prevent or treat the sight-threatening disease, they say. The findings are in ACS' Journal of Proteome Research, a monthly publication.

Edward Feener and colleagues point out that diabetic retinopathy is a common complication of diabetes, which affects millions of people worldwide. It involves damage to blood vessels in the retina, the light sensitive tissue in the back of the eye. Previous studies suggested that drugs used to treat high blood pressure, including ACE inhibitors and angiotensin receptor blockers (ARBs), may help prevent the condition.

The scientists analyzed proteins from the retinas laboratory mice with normal blood pressure and diabetes and compared them to those of non-diabetic mice. They identified 65 abnormal proteins in the diabetic mice out of more than 1,700 proteins in the study. Treatment with the ARB medication, candesartan, prevented the abnormal changes in more than 70 percent of the proteins.

Journal of Proteome Research: "Angiotensin AT1 receptor antagonism ameliorates murine retinal proteome changes induced by diabetes" [J. Proteome Res., 2009, 8 (12), pp 5541–5549; DOI: 10.1021/pr9006415].