Tamiflu not working for some H1N1 patients

November 24, 2009

Four patients at Duke University Medical Center in Durham, N.C., and at least five in an unidentified hospital in Wales have become infected with H1N1 viruses that no longer respond to treatment with Tamiflu. Flu viruses swap genes as part of their normal evolution; that means resistant viruses could quickly spread worldwide, says Duke’s Daniel Sexton.

Read more:  http://www.usatoday.com/news/health/2009-11-23-swinefluupdate23_ST_N.htm

Prepare yourself for H1N1 using safety products from Cole-Parmer

Snippet compliments of Steve Sternberg, USA TODAY.

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Barbie and Disney toys still have high levels of lead

November 23, 2009

By JENNIFER C. KERR, Associated Press Writer Jennifer C. Kerr, Associated Press Writer

WASHINGTON – Children’s toys carrying the Barbie and Disney logos have turned up with high levels of lead in them, according to a California-based advocacy group — a finding that may give consumers pause as they shop for the holiday season.

The Center for Environmental Health tested about 250 children’s products bought at major retailers and found lead levels that exceeded federal limits in seven of them. Lead can cause irreversible brain damage.

Among those with high lead levels: a Barbie Bike Flair Accessory Kit and a Disney Tinkerbell Water Lily necklace. The group said it also found excessive lead in a Dora the Explorer Activity Tote, two pairs of children’s shoes, a boys belt and a kids’ poncho.

California Attorney General Jerry Brown has sent letters to Target, Wal-Mart and the other retailers who sold the seven products, warning that children’s goods on their store shelves were found to contain illegal levels of lead and should be pulled immediately.

The findings released Tuesday come about a year after a product safety law that ushered in strict limits on the amounts of lead and chemicals allowed in products made for children 12 years and younger. Congress passed the law after a slew of recalls of lead-tainted toys in 2007, including several Mattel-related recalls that involved more than 2 million toys.

Mattel said it licensed the Barbie name to Bell Sports for the bike accessory kit found with high lead, but did not make or sell it. Bell said the kit was an older product that passed safety tests in 2007, but the company didn’t know it was still on store shelves.

Disney said the Tinkerbell necklace was tested by its licensee, Playmates Toys, before being distributed — and that it complied with all federal and state consumer safety regulations.

The Center for Environmental Health in Oakland, Calif., said the Barbie toy was bought at Tuesday Morning and the Tinkerbell jewelry was purchased at Walgreens. The other products the center said had high lead came from TJ Maxx, Sears, Wal-Mart and Target.

The center’s executive director, Michael Green, said parents “need to know that there are still some lead problems on store shelves.”

The center did an initial round of testing on products and sent the ones singled out as having high lead to an independent laboratory for additional testing and confirmation.

The Consumer Product Safety Commission, which regulates toys and thousands of other products, is looking into the matter.

Commission Chairman Inez Tenenbaum held a meeting with parents and consumers Tuesday in New York to praise the new safety protections provided in the consumer law, known as CPSIA. She said lead recalls are down this year and that CPSIA should give consumers greater confidence while shopping for toys during the holiday season.

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Why is Juan Valdez so bitter? It’s not the caffeine.

November 16, 2009

Published with permission. Initially published in the IFT Weekly Newsletter, August 22, 2007

What makes coffee so bitter, aside from being constantly cast as a wake-up caller? Two classes of compounds have been ID’d as the perpetrators, according to chemists in Germany and the United States who say they have identified the chemicals that appear to be largely responsible for java’s bitterness, a finding that could one day lead to a better tasting brew. Their study, one of the most detailed chemical analyses of coffee bitterness to date, was presented Tuesday at the American Chemical Society national meeting in Boston.

Research by others over the past few years has identified an estimated 25 to 30 compounds that could contribute to the perceived bitterness of coffee. But the main cause of coffee bitterness has remained largely unexplored until now, the researchers say.

“Everybody thinks that caffeine is the main bitter compound in coffee, but that’s definitely not the case,” said study leader Thomas Hofmann, Ph.D., a professor of food chemistry and molecular sensory science at the Technical University of Munich in Germany. Only 15 percent of java’s perceived bitterness is due to caffeine, he estimates, noting that caffeinated and decaffeinated coffee both have similar bitterness qualities.

Roasting is the key factor driving bitter taste in coffee beans. “So the stronger you roast the coffee, the more harsh it tends to get,” Hofmann says, adding that prolonged roasting triggers a cascade of chemical reactions that lead to the formation of the most intense bitter compounds.

Using advanced chromatography techniques and a human sensory panel trained to detect coffee bitterness, Hofmann and his associates found that coffee bitterness is due to two main classes of compounds: chlorogenic acid lactones and phenylindanes, both of which are antioxidants found in roasted coffee beans. The compounds are not present in green (raw) beans, the researchers note. Ironically, the lactones and the phenylindanes are derived from chlorogenic acid, which is not itself bitter.

Chlorogenic acid lactones, which include about 10 different chemicals in coffee, are the dominant source of bitterness in light to medium roast brews. Phenylindanes, which are the chemical breakdown products of chlorogenic acid lactones, are found at higher levels in dark roasted coffee, including espresso. These chemicals exhibit a more lingering, harsh taste than their precursors, which helps explain why dark-roasted coffees are generally more bitter, Hofmann says.

Perception of bitterness can also be influenced by how the coffee is brewed.. Espresso-type coffee, which is made using high pressure combined with high temperatures, tends to produce the highest levels of bitter compounds. While home-brewed coffee and standard coffee shop brews are relatively similar in their preparation methods, their perceived bitterness can vary considerably depending on the roasting degree of the beans, the amount of coffee used, and the variety of beans used.

Some instant coffees are actually less bitter than regular coffee, Hofmann says. This is because their method of preparation, namely pressure extraction, degrades some of the bitter compounds. In some cases, as much as 30 to 40 percent fewer chlorogenic acid lactones are produced, leading to a reduced perception of bitterness, he says.

“Now that we’ve clarified how the bitter compounds are formed, we’re trying to find ways to reduce them,” Hofmann says. He and his associates are currently exploring ways to specially process the raw beans after harvesting to reduce their potential for producing bitterness. They are also experimenting with different bean varieties in an effort to improve taste. But so far, none of these approaches—details of which are being kept confidential by the researchers—is ready for commercialization, he notes.

What makes coffee bitter?
Oral Presentation, August 21, 2007
American Chemical Society National Meeting
Boston, Mass.

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Using Your Nose

November 13, 2009

Written by:  Ben Wilbert, Product Manager, Cole-Parmer
While most scientists who study human brain evolution tend to regard something people do very well, such as language, Dr. Tyler Lorig, Ph.D. at Washington & Lee University studies one of the least understood senses and something people tend not to do so well: smell. With an interest in brain evolution and a background in EEG analysis, he studies the olfactory (a.k.a. sense of smell) system in his lab, specifically how the brain responds to an odor. Often a neglected and under-served field of science, and past research often fraught with loose control methods, Dr. Lorig decided to develop his own olfactometer. Since an olfactometer isn’t exactly the type of device you’d find on the shelf of the hardware store—or even in a specialty catalog—Dr. Lorig built his olfactometer by using many quality products from the Cole-Parmer catalog, starting with solenoid valves. The one he devised proved to be much less expensive than one valued at $100,000 on the market, yet served all the needs of his research.

One of the challenges to studying the sense of smell is being able to appropriately regulate the amount of the stimulus. It’s difficult to determine how much of an odor you’ve delivered to a test subject. While you may try and “dose” the amount of smell, there are many factors affecting the distribution of airborne molecules that provide an odor. In studying the body’s other natural senses, it’s comparatively easy to gauge precisely how much of a stimulus is applied to a subject. Light, sound, electricity, and even flavors—although taste is a field of study filled with ambiguity itself—can be regulated to keep tight controls over a scientific test. But in testing the olfactory response, even the weight of the molecule, for instance, will affect how fast it disperses, and hence sensed by someone. Lighter molecules move quicker, so if you’ve decided to expose the test subject to five seconds of a particular odor, you will get a different result than a heavier molecule that only gets a fraction of the activity in the air within the same time frame. This means lightweight molecules will invade the nose, migrate through the mucous membrane at the top of the nasal cavity, and be sensed more so than heavier molecules. To top it all off, there is even remarkable inter-subject variability, whereby one person may sense an odor sooner or later than another person.

To minimize the effects of the inherent differences in the physical nature of odors and test subjects themselves, the equipment used has to be of such design and quality that the experiment is not compromised. All parts of Dr. Lorig’s olfactometer that could contaminate smells are high purity, hence minimizing any residual odor that would affect the experiment results. Lorig admits to first coming to Cole-Parmer while looking for some high-quality solenoid valves. He sought PTFE (wetted parts) valves because of PTFEs quality to stay clean, and not absorb errant odors. In his paper “A computer-controlled olfactometer for fMRI and electrophysiological studies of olfaction”, originally published in Behavior Research Methods, Instruments, and Computers, Lorig describes the design for an inexpensive and reliable olfactometer that he pieced together and constructed from off-the-shelf chromatography parts that required little modification. Since he would be using the olfactometer near an fMRI, the olfactometer had to obviously be free of ferrous metals, which will wreak havoc near the magnet. Overall, the instrument needed essentially seven features: (1) computer control; (2) effective delivery of a variety of odors, in series or randomly; (3) production of an odor stimulus of selectable and reliable duration in a constant airstream, without any additional type of ancillary stimulation (e.g., tactile, auditory); (4) resistance to contamination; (5) durability; (6) ease of operation, refilling, and cleaning; and (7) low cost (Lorig et al. 1999).

Following the drawing above, air from a compressor is passed through a charcoal filter to remove odors and then through particulate filters to prevent charcoal dust from being administered to test subject. After passing through the particulate filters the flow is divided and metered through variable-area flowmeters. One of the lines is always open and provides a constant low-volume air stream. The other flowmeter provides the air that will be passed over the odors. This stream is also divided and passed to two solenoid valves. Valve A is a single valve that is normally open. The other valve is a multi-port valve that can have from 1 to 6 individual normally closed solenoid valves (B1-6). To send an odor to a subject, the computer turns on valve A (stopping airflow in that line) and turns on valve Bn commencing airflow in that line. The syringe filter connected to line Bn contains odor, and the air now passes over the filter and through the manifold to the subject. Turning the valve off stops airflow over the filter paper and stops the blockage cause by actuating valve A. To avoid any increases in air flow, one non-odorized line is stopped during odor stimulation making the net change in air zero. Because the switching in the valves lead to very brief airflow changes (around 20 milliseconds) the constant flow line acts as a buffer for the airflow change, thereby reducing any extraneous sensory stimulation to the test subject.

“Some of the research done shows we are exquisitely sensitive to smells, contrary to our expectation.” states Lorig.

In relatively normal test subjects, Lorig finds people have measurable brain activity induced by odors, even when the test subject reports not smelling anything! Even when more than one chemical is blindly switched—neither reported as smelled—they render different brain responses. While brain patterns related to particular smells may evoke similar and predictable brain responses, Lorig is careful not to jump too far in his conclusions, for example, they will not indicate emotions such as fear or joy.

Lorig notes that when it comes to the extreme smells, people tend to agree across cultural boundaries as to what smells bad and what smells good. On the bad end of the spectrum, odors such as feces and cadavers evoke similar negative responses from people, and on the pleasant end, vanilla ranks universally high as a positive response from people. But in the vast midsection of the odor continuum, there is a wide variance regarding what is pleasant versus not-so-pleasant odors. Other interests include why some people find certain odors pleasant or at least tolerable, while others find them absolutely repugnant.

“Since I’ve talked to so many people about smell, they will sort of confess, ‘Oh, I really like skunk smell.’ ”

While much of the current olfaction study takes place in a research setting, Lorig states he would like to see olfaction analysis become simplified and used more in clinical applications. There’s now understanding of the connection between olfaction and certain health problems. Current research examines the relationship between olfaction and maladies such as Parkinson’s Disease, Huntington’s Disease, Korsakoff’s Syndrome, Schizophrenia, Depression, and Alzheimer’s Disease (AD). Recent evidence suggests that areas in the central nervous system processing olfactory information are affected at the early stages of AD, even before the onset of cognitive decline, and that olfactory dysfunction might be an early indicator of AD (Murphy, 1999). The smell threshold is much higher for those who suffer from AD.

Aside from aiding pathological diagnosis, Lorig’s current and future toils include researching how the brain is organized, the pathways the brain uses to process odors, and the many relationships between smelling and the other senses. Cole-Parmer continues to provide scientific instruments used by these professionals to support the overall advancement of science. We thank Dr. Lorig for his time and efforts in providing valuable feedback about our products and wish him well in his future endeavors.

References
Lorig TS, Elmes DG, Zald DH, Pardo JV (1999) A computer-controlled olfactomenter for fMRI and electrophysiological studies of olfaction. Behav Res Methods Instrum Comput 31: 370-375.

Murphy, C., 1999. Loss of olfactory function in dementing disease. Physiol. Behav. 66 (2), 177-182.

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Attention all wannabe mad scientists! A brief history of the Van de Graaff generator and tips on how to build your own.

October 30, 2009
Van de Graaff electrostatic generator October 2009 marks the 80th anniversary of the Van de Graaff electrostatic generator. While this machine is widely recognized for its loud sparks and hair-lifting demonstrations, more importantly it represents a significant benchmark in the production of static electricity at high voltages.

Dr. Robert J. Van de Graaff developed the electrostatic generator in 1929 while he was a research fellow at Princeton University. He moved to the Massachusetts Institute of Technology where, between the years of 1931 and 1933, he crafted a larger generator that produced significantly higher voltages. While at MIT, he developed the world’s largest Van de Graaff generator which is currently displayed at the Boston Museum of Science.

The Van de Graaff generator is sometimes mistaken for the Tesla coil because of similarities in appearance. However, Nikola Tesla’s invention—which predates the Van de Graaff generator by nearly 40 years—has a completely different function. The Van de Graaff generator creates static electricity, while the Tesla coil creates high-voltage current electricity that is transferrable through the air into other objects (e.g. a light bulb). Nevertheless, Tesla recognized the generator’s potential in the 1934 article titled “Possibilities of Electrostatic Generators,” when he referred to the Van de Graaff generator as a “remarkable device,” agreeing with the assertion “with which wonders will be achieved.” †

Tesla’s statement would prove to be correct. Because of its use of a power supply to a produce continuous static electricity, the Van de Graaff generator quickly eclipsed previous electrostatic models.

Basic principles of the Van de Graaff generator

They come in many sizes, but each Van de Graaff generator is comprised of three central components: the terminal, a belt and pulley system, and a motor. The terminal is the insulated hollow metal sphere elevated at the highest point of the machine where the current is expelled.

basic priciples of the Van de Graaf generator

The belt and pulley system features an insulating belt which transfers charges to the terminal. The belt creates static through friction with a metal electrode, also known as a needle or comb. There are two pulleys—each with a corresponding electrode—in place: one at the bottom of the machine, connected to the motor, and another positioned within the base of the terminal. One side of the belt carries a positive charge, while the opposite carries a negative charge. Both pulleys are contained in a hollow cylinder that is connected to the sphere.

Lastly, at the base, a switch-operated motor powers the generator.

The mother of all science fair projects

Constructing your own Van de Graaff can be a fairly straightforward process. Moreover, it is a safe, cheap, and fun way to demonstrate the properties of static electricity. To commemorate the Van de Graaff generator’s 80th birthday—and to help you stay on the cutting edge of the 20th century—here are few pointers to consider when building your generator:

  1. The most crucial part of the generator is the terminal. As such, to achieve the greatest charge, you should only use a round hollow sphere made of stainless-steel or aluminum. To test the effectiveness of the generator, you can place a negatively charged metal object close to sphere to make a spark. Even more illustrative, place your hands on the sphere and in an instant the hairs on your head will stand up.
  2. The belt is also very important. To create the most static, use a belt made of vinyl or silk. Be sure that the belt is bound tightly to the pulleys so it is unable to move laterally. (Also, bear in mind, the belt and terminal are the most difficult pieces to replace.)
  3. To ensure your machine stays intact, use a strong adhesive to firmly attach the metal sphere to cylinder—PVC piping is highly recommended—surrounding the belt.
  4. The electrodes are also pivotal in the performance of your generator. For both pulleys, position the ends of electrodes close to the belt without touching it.
  5. Lastly, make sure your surrounding conditions are not damp or humid. The generator may not work in such conditions.
If you would like assistance in building your own Van de Graaff generator, talk to a Cole-Parmer Application Specialist. These experts enjoy walking through all types of projects—be it challenging, mundane, or fun! Cole-Parmer also offers Custom Ordering Solutions to meet any desired product modifications.

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Attention all Meat Packers (and other packers), Modified Atmosphere Packaging extends shelf life without requiring chemical preservatives or stabilizers

October 26, 2009
Meat, Veggies and Cheese

Meat, Veggies and Cheese - Modified Atmosphere Packed

Modified Atmosphere Packaging – A fresh and wholesome presentation
Protective Atmosphere enables fresh and minimally processed packaged food products to maintain visual, textural and nutritional appeal. The controlled MAP environment enables food packaging to provide an extended shelf life without requiring the addition of chemical preservatives or stabilisers.

Processors and marketers of food products rely on Modified Atmosphere Packaging to assure fresh and flavourful products that continually meet the consumer’s expectation for brand quality, consistency, freshness and in-stock availability.

More information is also avalible on www.modifiedatmospherepackaging.com

What is Modified Atmosphere Packaging?
Modified Atmosphere Packaging is an optimal blend of pure oxygen, carbon dioxide and nitrogen within a high barrier or permeable package. A finely adjusted and carefully controlled gas blend is developed to meet the specific respiration needs for each packaged food product.

Plastic films, foils and other packaging materials that demonstrate specified gas permeability properties and/or water vapour permeability properties are selected for use. These high barrier substrates become MAP Packages after they are formed into trays, lid stock or bags and filled with a select blend of oxygen, carbon dioxide and nitrogen environmental gasses.

Packaging films are selected to match the characteristics and needs of the food product. Film permeability, water vapour transmission rates and sealing characteristics need to be measured and tested at film selection and again at package converting and product fill stages, since the ability of a film to handle MAP performance characteristics may vary within each stage.

How does Modified Atmosphere Packaging work?
The Modified Atmosphere Package environment is formed from a finely balanced mix of normal atmospheric gases. The finely balanced MAP gas mix slows down the product aging process to reduce colour loss, odour and off-taste resulting from product deterioration, spoilage and rancidity caused by mold and other anaerobic organisms.

A carefully controlled Modified Atmosphere Package achieves and maintains an optimal respiration rate to preserve the fresh colour, taste and nutrient content of red meat, seafood, minimally processed fruits and vegetables, pasta, prepared foods, cheese, baked goods, cured meats and dried foods throughout an extended shelf life.

Modified Atmosphere Packaging offers supply chain efficiencies
Longer shelf life MAP packages allow food processors, food manufacturers, food distributors and food retailers to better control product quality, availability and costs.

Longer freshness cycles permit grocers to eliminate frequent product rotation, removal and restocking; thereby reducing labour and waste disposal costs.

Distributors can extend distribution territories or offer a greater variety of product lines to the retailer, since less frequent product replacement requirements permits growth in other areas.

Food manufacturers are able to take advantage of extended replacement cycles to reduce production replacement demands. Manufacturing capacity can be more profitably utilised by developing and offering new products.

Testing assures Modified Atmosphere Packaging integrity
Performance characteristics of Modified Atmosphere Packages are easily tested to assure that packages meet quality standards. Convenient, reliable and easy-to-use gas analysers, gas mixers, gas control solutions, permeability testers and package leak detectors are available. MAP package testers evaluate, measure, adjust, control and test the modified atmosphere package environment.

Random package testing
Spot testing instruments can check, measure and analyse the amount of “head-space” air between the product and the package substrate within a random sampling of packages. Random MAP testing is typically done at pre-set intervals throughout the packaging operation to assure consistency. Spot testers, which rely on built-in air collection pumps to prevent atmospheric air from entering the package, offer immediate readings.

Hand-held headspace gas analysers offer a fast check on oxygen or oxygen and carbon dioxide gas combinations within representative package samples.

Gas analysers automatically measure and record in a seamless process that provide uniform, traceable data reports. Measurements are displayed on a screen, stored in the computer and may be simultaneously sent to a printer, when a paper record is desired.

On-line quality control
Regular, systematic in-line testing of every package provides total output assurance to measure package integrity and management of the MAP gas blend. When installed onto a flow-wrapping machine, a single test unit interfaces with each package to measure its on-line gas composition and evaluate the targeted oxygen level.

Automatic flow control enables a packaging machine operator to adjust filling speeds without impacting the oxygen level. When combined with an automated gas flushing system, the operator is able to gain greater control over both gas mix and package filling speeds.

A fully automated in-line, all-in-one package testing and gas mix blending controller is available to measure, evaluate and adjust the MAP gas mix for each package. Greater control over each package assures that each package has an optimum gas mix. In addition to providing package-to-package uniformity, the seamless package measurement and precision gas adjustment process assures a more efficient gas usage with a corresponding cost savings.

MAP testing options for thermoformed packages
On-line gas monitoring equipment tests two critical areas for assuring quality in MAP packages. In the first analysis, measurement is made to check the actual oxygen or oxygen and carbon dioxide gas blend put into thermoformed packages and tray sealers. Secondly, the reading reveals air leaks within each package. These leaks are typically caused by faulty maintenance or misalignment of dies or sealing heads on thermoforming and tray sealing machinery.

MAP package measurement tests are performed on-line during both the vacuum and injection process without causing disruption or delay.

Protection against leaks
Finished modified atmosphere package leak testing and package stress testing equipment is used to verify package integrity and seal strength. Unlike messy, manual old-fashioned water testing, new non-destructive testing technology uses carbon dioxide CO2 as a trace gas in a fast, easy, user-independent test.

As part of an overall quality check, leak testing can be conducted in a closed, airtight chamber at each stage within the package forming process and during final package output.

Annual calibration offers one-time setup for maximum reliability
Advances in gas analyser technology requires less frequent instrument calibration. Once a year calibration is now available to offer greater reliability and faster set-up. Checking of recorded calibration data should be made using certified gases.

MAP package quality assurance
Although Modified Atmosphere Packaging is a well-established process, it is a good practice to maintain tight quality control through package testing. Incorrect oxygen levels, empty gas tanks and bad sealing bars can cause imprecise gas blends and poor package seals that can result in product spoilage. Routine package testing with gas analysers assures package quality, uniformity and brand consistency.

Complete Selection of CheckMate II O2 and O2/CO2 Analyzers
Complete Selection of CheckPoint O2 and CO2/O2 Analyzers

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