Scientists develop the world's thinnest balloon
Researchers in New York are reporting development of the world's thinnest balloon, made of a single layer of graphite just one atom thick. This so-called graphene sealed microchamber is impermeable to even the tiniest airborne molecules, including helium. It has a range of applications in sensors, filters, and imaging of materials at the atomic level, they say in a study scheduled for the August 13 issue of ACS' Nano Letters.
Paul L. McEuen and colleagues note that membranes are fundamental components of a wide variety of physical, chemical and biological systems, found in everything from cellular compartments to mechanical pressure sensing. Graphene, a single layer of graphite, is the upper limit: A chemically stable and electrically conducting membrane just one atom thick. The researchers wanted to answer whether such an atomic membrane would be impermeable to gas molecules and easily incorporated into other devices.
Their data showed that graphene membranes were impermeable to even the smallest gas molecules. These results show that single atomic sheets can be integrated with microfabricated structures to create a new class of atomic scale membrane-based devices. We envision many applications for these graphene sealed microchambers, says McEuen. These range from hyper-sensitive pressure, light and chemical sensors to filters able to produce ultrapure solutions.
"Impermeable Atomic membranes from Graphene Sheets"
DOWNLOAD FULL TEXT ARTICLEhttp://dx.doi.org/10.1021/nl801457b
Test to protect food chain from human form of Mad Cow DiseaseJournal of Agricultural and Food Chemistry
Scientists are reporting development of the first test for instantly detecting beef that has been contaminated with tissue from a cow's brain or spinal cord during slaughter — an advance in protecting against possible spread of the human form of Mad Cow Disease. The study is scheduled for the August 13 issue of ACS' bi-weekly Journal of Agricultural and Food Chemistry.
Jürgen A. Richt and colleagues point out that removal of brain, spinal and other central nervous tissue after slaughter is "one of the highest priority tasks to avoid contamination of the human food chain with bovine spongiform encephalopathy," better known as Mad Cow Disease. "No currently available method enables the real-time detection of possible central nervous system (CNS) tissue contamination on carcasses during slaughter," the report states.
They describe a test based on detection of the fluorescent pigment lipofuscin, a substance that appears in high concentrations in the nervous tissue of cattle. The researchers found that it was a dependable indicator for the presence of brain and spinal tissue in bovine carcasses and meat cuts. "Small quantities of bovine spinal cord were reliably detected in the presence of raw bovine skeletal muscle, fat and vertebrae. The research lays the foundation for development of a prototype device allowing real-time monitoring of CNS tissue contamination on bovine carcasses and meat cuts," the report says. It was done with colleagues from the National Animal Disease Center of the USDA-Agricultural Research Service and Iowa State University. — AD
ARTICLE #2 FOR IMMEDIATE RELEASE"Fluorescence-Based Method, Exploiting Lipofuscin, for Real-Time Detection of Central Nervous System Tissues on Bovine Carcasses"
DOWNLOAD FULL TEXT ARTICLEhttp://dx.doi.org/10.1021/jf0734368
Scientists have developed the world's thinnest balloon that is impermeable to even the smallest gas molecules. Above is a multi-layer graphene membrane that could be used in various applications, including filters and sensors.
(Photo Credit: : Jonathan Alden)
New evidence on benefits of breast feedingJournal of Proteome Research
Researchers in Switzerland and Australia are reporting identification of proteins in human breast-milk — not present in cow's milk — that may fight disease by helping remove bacteria, viruses and other dangerous pathogen's from an infant's gastrointestinal tract. Their study is scheduled for the September 5 issue of ACS' Journal of Proteome Research.
Niclas Karlsson and colleagues point out that researchers have known for years that breast milk appears to provide a variety of health benefits, including lower rates of diarrhea, rashes, allergies, and other medical problems in comparison to babies fed with cow's milk. However, the biological reasons behind this association remain unclear.
To find out, the scientists collected human and cow's milk samples and analyzed their content of milk fat. They found that fat particles in human milk are coated with particular variants of two sugar-based proteins, called MUC-1 and MUC-4. Previous studies by others have shown that these proteins can block certain receptors in the GI tract that are the main attachment sites for E. coli, Helicobacter pylori and other disease-causing microbes, thereby preventing infection. By contrast, since cow's milk lacks these protein variants, it may not offer the same disease protection, the researchers say.
ARTICLE #3 FOR IMMEDIATE RELEASE"Glycoproteomics of Milk: Differences in Sugar Epitopes on Human and Bovine Milk Fat Globule Membranes"
DOWNLOAD FULL TEXT ARTICLEhttp://dx.doi.org/10.1021/pr700793k
Scientists have identified sugar-based proteins in human breast-milk that could help fight disease.
(Photo Credit: : Niclas Karlsson)
A new look at the "biobed's" role in pesticide spillsJournal of Agricultural and Food Chemistry
Scientists in Sweden are cautioning about the need for further research as more countries embrace a popular method for preventing pesticide spills. Their review of current scientific knowledge on the so-called "biobed" is scheduled for the August 13 issue of ACS' bi-weekly Journal of Agricultural and Food Chemistry.
In the study, Maria Del Pilar Castillo and colleagues point out that pesticide spills are common when farmers transfer highly concentrated liquid preparations into spray tanks where the pesticide is diluted with water. Even if a small, few-inch wide puddle of this concentrate spilled under the tank, the nearby environment could be exposed to up to one hundred thousand times the normal pesticide dose. "The risk of contamination is obvious," says Castillo.
To remedy the problem, Swedish scientists in 1993 developed the biobed. Built from layers of grass, clay and a biomixture of straw, peat and soil approximately two feet deep, the biobed functions as an absorbent sponge for leaking concentrate from parked spray tanks.
Castillo says the effectiveness and simplicity of biobed systems help them spread worldwide. But as biobeds are modified to suit local conditions and needs, she cautions that it is important to analyze their actual performance in each specific location and evaluate the effects of changes to the biobed's composition and how local temperature and other conditions affect performance.
"Biobeds for Environmental Protection from Pesticide Use – A Review"
DOWNLOAD FULL TEXT ARTICLEhttp://dx.doi.org/10.1021/jf800844x
Toward a drug-free Olympics: Analytical chemistry takes center stageChemical & Engineering News
In the most comprehensive drug-testing effort in sports history, Olympic officials are taking unprecedented steps to make sure this year's athletes compete without the use of performance enhancing drugs. But despite improvements in drug-testing techniques, catching athletes who cheat remains difficult, according to an article scheduled for the August 11 issue of Chemical & Engineering News.
In a feature article in the magazine, C&EN Senior Correspondent Marc S. Reisch points out that Olympic officials will spend about $10 million testing athletes for performance enhancing drugs, including round-the clock monitoring of urine and blood samples. Many of these tests will focus on identifying human growth hormone (hGH) and erythropoietin (EPO), two products of recombinant DNA technology that athletes have used to boost muscle mass and increase endurance.
Although analytical instruments have become more accurate, reliable, and capable over the years, catching cheaters remains a virtual cat and mouse game. One challenge is the use of custom-synthesized "designer" drugs, which are difficult to identify and test, according to the article. But with more money and effort going into testing, athletes are likely to think twice before using performance enhancing drugs, the article suggests.
"Drugs at the starting line"
This story will be available on August 11 athttp://pubs.acs.org/cen/business/86/8632bus1.html