Friday, April 6, 2012

A capsule for removing radioactive contamination from milk, fruit juices, other beverages

In a presentation at the 243rd National Meeting & Exposition of the American Chemical Society (ACS) they said the technology could be used on a large scale by food processors or packaged into a small capsule that consumers at the home-kitchen level could pop into beverage containers to make them safe for consumption.

"We repurposed and repackaged for radioactive decontamination of water and beverages a tried-and-true process that originally was developed to mine the oceans for uranium and remove uranium and heavy metals from heavily contaminated water," said Allen Apblett, Ph.D., who led the research team. "The accident at the nuclear plant in and ongoing concerns about possible terrorist use of that may contaminate food and water led us to shift the focus of this technology."

The technology also can remove arsenic, lead, cadmium and other heavy metals from water and , Apblett said, adding that higher-than-expected levels of some of those metals have been reported in the past in certain juices. He is with Oklahoma State University in Stillwater.

Nanoparticles composed of metal oxides, various metals combined with oxygen, are the key ingredients in the process. The particles, so small that hundreds would fit on the period at the end of this sentence, react with radioactive materials and other unwanted substances and pull them out of solution. The particles can absorb all 15 of the so-called "actinide" chemical elements on the periodic table of the elements, as well as non-actinide radioactive metals (e.g., strontium), lead, arsenic and other non-radioactive elements.

The actinides all are radioactive metals, and they include some of the most dangerous substances associated with nuclear weapons and commercial nuclear power plant accidents like Fukushima. Among them are plutonium, actinium, curium and uranium.

In the simplest packaging of the technology, the metal-oxide nanoparticles would be packed inside a capsule similar to a medicine capsule, and then stirred around in a container of contaminated water or fruit juice. Radioactive metals would exit the liquid and concentrate inside the capsule. The capsule would be removed, leaving the beverage safe for consumption. In laboratory tests, it reduced the concentrations of these metals to levels that could not be detected, Apblett noted.

The technology is moving toward commercialization, with the first uses probably in purifying calcium dietary supplements to remove any traces of lead, cadmium and radiostrontium. Apblett said the capsule version could have appeal beyond protection against or nuclear accidents, among consumers in areas with in their water or food supplies, for instance.

More information: Abstract
Nuclear accidents such as the ones at the Fukushima nuclear plant in Japan and at Chernobyl along with the legacy of past use and testing of nuclear weapons have highlighted the need for technologies to decontaminate food and water that contain radionuclides. The potential for future nuclear wars and even the contamination of food and water by spent uranium penetrators further delineate the need for technologies to protect animals and the public. We have developed technologies based on nanoparticulate metal oxides that have very high capacity for radionuclides. For example, they can be used to remove radiostrontium from milk. The use of suitably-derivitized nanoporous silicas for this purpose will also be discussed.

Provided by American Chemical Society (news : web)

EMSL's novel spectroscopy device pairs visual clarity with sub-monolayer sensitivity

EMSL staff and users from the Chinese Academy of Sciences analyzed polarization-dependent SFG vibrational spectra of the monovalent -CN groups buried in the C18CN (organic cyanide) insoluble Langmuir monolayer at the air–water interface.

These one-molecule-thick layers are the model system for studying structure and interactions at confined dimensions and serve as the building block for functional materials, as well as agents in broad industrial applications.

Because of its large dipoles and a vibrational spectrum that is sensitive to inhomogeneous chemical environments, –CN often is used as the probe in materials and biological studies. HR-BB-SFG-VS analyses of the C18CN monolayer revealed two previously indistinguishable vibrational spectroscopic -CN shifts that are distinct but closely overlapping at the more hydrophobic 2244.5 cm-1 and in direct contact with water at 2251.1 cm-1.

data pinned the orientation angles for these two -CN groups as 67° and 50°, respectively.

The unprecedented structural and interaction details afforded by HR-BB-SFG-VS—especially new knowledge about buried interfaces such as solid/liquid, liquid/liquid, and solid/solid, as well as on nanoparticles and porous surfaces—can impact areas such as catalysis, biogeological chemistry, and beyond.

More information: Zhang Z, et al. 2012. “Resolving Two Closely Overlapping -CN Vibrations and Structure in the Langmuir Monolayer of the Long-Chain Nonadecanenitrile by Polarization Sum Frequency Generation Vibrational Spectroscopy.” Journal of Physical Chemistry C 116(4):2976-2987. DOI: 10.1021/jp210138s

Provided by Environmental Molecular Sciences Laboratory (news : web)

Standard test may miss food ingredients that cause milk allergy

Joseph L. Baumert, Ph.D., who headed the study, explained that thermal and non-thermal processing of foods can change the proteins responsible for in ways that make the proteins harder to detect using the standard test, termed the enzyme-linked immunosorbent assay (ELISA). Processing, however, may still leave the proteins capable of causing itchy skin, runny eyes, wheezing and other sometimes more-serious symptoms of milk allergy, despite the inability to detect the milk residue.

"The results of these studies could be utilized by commercial ELISA kit manufacturers to aid in improving ELISAs for detection of milk residue in processed food products. These improved tests can be adopted by the food industry, if necessary, to allow for reliable detection of milk residue regardless of the type of processing that is used," he said. "These improvements should not result in commercial tests that are more expensive or difficult for food processors to use."

Food processors use the ELISA to assure that that do not contain milk and processing equipment in facilities that process milk products are free of milk allergens, the substances that can trigger milk allergy.

Milk allergy is not the same as lactose intolerance, a condition in which people lack adequate amounts of the enzyme needed to digest lactose, the main sugar in milk. Lactose intolerance involves the digestive system, with symptoms like bloating, stomach cramps and diarrhea, after consuming milk or milk products. Milk allergy affects the immune system and can cause swelling of the throat, which makes it difficult to breath, and other symptoms that require immediate medical help.

Baumert explained that manufacturers and food-safety agencies use ELISAs to ensure that food-processing equipment and finished products are free of allergens or labeled with appropriate warnings. ELISAs are one of the most widely used diagnostic tests in the world today, a mainstay in everything from diagnosing pregnancy and detecting the AIDS virus in human blood to diagnosing a range of other diseases in plants and animals. The tests leverage the amazing ability of antibodies, proteins formed by the body's immune system, to attach to and mark for destruction bacteria, viruses and other foreign substances. An ELISA kit for milk proteins contains antibodies that bind to milk proteins that may be in a finished food product or on the surface of shared manufacturing equipment. If a sample taken from a finished product or from the surface of food-processing equipment contains milk residue, a color change will occur in the test, indicating a positive result for contamination with milk proteins.

Baumert, who is with the University of Nebraska-Lincoln, explained that heating and other processing of foods can make milk proteins aggregate together so it is difficult to get the milk proteins into solution, which enables them to be detected by the antibodies in ELISAs. The clumping, however, does not necessarily destroy the protein's ability to trigger an allergic reaction in sensitive people. Clumped-together proteins also would be likely to maintain their potency once they reached the human body, he added. Heating and other processing can also alter the structure of the protein, which can affect the ability of the antibody to bind to the milk proteins. Alteration in the protein structure does not necessarily mean that the milk proteins become non-allergenic for the majority of milk-allergic individuals.

His team studied and documented how ELISAs perform on several measures of accuracy when milk proteins undergo changes in foods that are boiled, baked, fried or heated in other ways. The results could help the food-processing industry and ELISA manufacturers make changes that better protect consumers with milk allergies, he said, noting that other scientists are doing similar research on foods that contain eggs and peanuts — both common causes of .

More information:
Commercial enzyme-linked immunosorbent assays (ELISAs) are commonly used by food industry for validating removal of allergenic residue from food contact surfaces and detection of allergenic residue in finished products. ELISAs are the method of choice due to their specificity, sensitivity, and ease of use in an industrial setting, however, limited validation of ELISA kits has been conducted on food matrices that have undergone thermal processing. This is important to note when selecting a commercial milk ELISA for monitoring allergenic residues as several variations in formats (qualitative and quantitative assays), specificity (detection of total milk protein, casein, or beta-lactoglobulin), sensitivity, and reporting units (NFDM, skim milk powder, casein, beta-lactoglobulin) exist. Milk proteins can be differentially affected by thermal processing thus limiting detection and affecting overall risk-assessment decisions. The effects of common processing techniques (boiling, baking, frying, retorting, and UHT) on detection of milk residue using commercial ELISAs will be discussed.

Provided by American Chemical Society (news : web)

Blocking 'oh-glick-nack' may improve long-term memory

Progress toward finding such a blocker for the sugar — with the appropriately malicious-sounding name "oh-glick-nack" — was the topic of a report here today at the 243rd National Meeting & Exposition of the American Chemical Society (ACS).

Linda Hsieh-Wilson, Ph.D., explained that the sugar is not table sugar (sucrose), but one of many other substances produced in the body's cells that qualify as sugars from a chemical standpoint. Named O-linked beta-N-acetylglucosamine — or "O-GlcNAc" — it helps in orchestrating health and disease at their origins, inside the billions of cells that make up the body. O-GlcNAc does so by attaching to proteins that allow substances to pass in and out of the nucleus of cells, for instance, and helping decide whether certain genes are turned on or off. In doing so, O-GlcNAc sends signals that may be at the basis of cancer, diabetes, Alzheimer's disease and other disorders. Research suggests, for instance, that proteins loaded up with too much O-GlcNAc can't function normally.

At the ACS meeting, Hsieh-Wilson described how research in her lab at the California Institute of Technology and Howard Hughes Medical Institute implicate O-GlcNAc in memory loss and cancer. The research emerged from Hsieh-Wilson's use of advanced lab tools for probing a body process that involves attachment of sugars like O-GlcNAc to proteins. Called glycosylation, it helps nerves and other cells communicate with each other in ways that keep the body coordinated and healthy. When O-GlcNAc is attached to a protein, that binding process is known as O-GlcNAc glycosylation.

Hsieh-Wilson's team screened the entire mammalian brain for all O-GlcNAc-glycosylated proteins, using a new process that her laboratory developed. They identified more than 200 proteins bearing O-GlcNAc attachments or tags, many for the first time. The research was done in mice, stand-ins for humans in research that cannot be done on people. Some of the proteins carrying O-GlcNAc were involved in regulating processes like drug addiction and securing long-term storage of memories.

O-GlcNAc's effects on one particular protein, CREB, got the scientists' attention. CREB is a key substance that turns on and regulates the activity of genes. Many of the genes in cells are inactive at any given moment. Substances like CREB, termed transcription factors, turn genes on. Hsieh-Wilson found that when O-GlcNAc attached to CREB, CREB's ability to turn on genes was impaired. When the researchers blocked O-GlcNAc from binding CREB, the mice developed long-term memories faster than normal mice.

Could blocking O-GlcNAc boost in humans?

"We're far from understanding what happens in humans," Hsieh-Wilson emphasized. "Completely blocking O-GlcNAc might not be desirable. Do you really want to sustain all memories long-term, even of events that are best forgotten? How would blocking the from binding to other proteins affect other body processes? There are a lot of unanswered questions. Nevertheless, this research could eventually lead to ways to improve memory."

In a related study, Hsieh-Wilson found that O-GlcNAc interacted with another protein in ways that encourage the growth of cancer cells, suggesting that blocking its attachment might protect against cancer or slow the growth of cancer. And indeed, in mouse experiments, blocking O-GlcNAc resulted in much smaller tumors.

Again, a treatment for humans based on this discovery is far in the future, but the study singles out O-GlcNAc as a potential new target for developing anti-cancer drugs.

More information: Abstract
Understanding the remarkable complexity of the brain on a molecular, cellular and systems level is one of the major challenges in science. The principles and tools of chemistry, when combined with biology, can be used to gain new insights into the molecules and interactions involved in cellular communication and memory storage. We will describe the synergistic application of chemistry and biology to explore the structure and function of carbohydrates and their impact in various biological contexts, including neuronal communication, long-term memory and cancer.

Provided by American Chemical Society (news : web)