In This Issue: Arrest Free Radicals and Help Put the Cuffs on Aging NIST Helps Make Benefits of Flat-Panel Displays Crystal Clear Don't Just Fight Tooth Decay ... Reverse It! Turning Tragedy into a Better Understanding of Radiation Effects Party at Midnight on New Year's Eve . Again! December Milestones Lined the Path to Closed Captioning on TV Tech Trivia
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Arrest Free Radicals and Help Put the Cuffs on Aging
Every living cell produces free radicalsmolecules containing oxygenas part of its normal metabolism. This natural process, however, has a dark side as people age. Free radicals are known to cause damage to the structure of DNA and have been associated with numerous age-related diseases such as cancer, atherosclerosis, Parkinsons and Alzheimers. Free radicals can take over as the bodys antioxidant defense mechanisms weaken, a condition referred to as oxidative stress. Additionally, external sources of free radicalsair pollution, radiation, ultraviolet light and certain drugscan tip the balance in the wrong direction.
NIST has developed groundbreaking methodologies for detecting and accurately measuring DNA that has been modified by free radicals to assist in the early diagnosis of age-related diseases.
To defend itself against DNA damage, the body naturally produces a number of repair enzymes. NIST is working with industry and the international research community to identify these enzymes and understand their functions. With this information, the pharmaceutical industry can develop drugs that mimic the enzymes to help the body fight disease. NIST also plans to develop standard reference materials that will provide benchmark measures for evaluating the level of oxidative damage in DNA samples for use by industry, clinical labs and academic researchers.
Pamela Houghtaling, (301) 975-5745
NIST Helps Make Benefits of Flat-Panel Displays Crystal Clear
Everyone loves flat-panel displays. Put your television flush against the wall and leave tons of space for the new sectional sofa. Carry your new laptop computer inside your briefcase with room to spare. But did you know that many of the measurements pivotal to making flat-panel technology workfor properties such as contrast ratio, reflection and colorimetrywere developed by the National Institute of Standards and Technology?
NISTs Electronics and Electrical Engineering Laboratory, in conjunction with the video electronics industry, has created an international flat-panel display measurement standard, which, in turn, has become the basis for how flat-panel
measurements are made worldwide. Benefiting are manufacturers, suppliers and consumers of the technology.
In one case, the standard was used by the Mayo Clinic Scottsdale (Ariz.) to spe-cify the purchase of 1,000 flat-panel displays for radiology. This allowed the clinic to migrate from printed X-rays to digital images viewed on flat-panel displays, a move that saves the clinic at least $1.5 million per year.
The health industry is not the only group that finds NISTs work on flat-panel display measurements extremely valuable. Aircraft manufacturers, such as Boeing, are incorporating flat-panel displays into state-of-the-art cockpit designs for safety as well as quality and cost considerations. For example, building a display screen to the accepted standard for contrast ratio ensures that a pilot will be able to clearly read critical data in all situations.
Philip Bulman, (301) 975-5661
Don't Just Fight Tooth Decay ... Reverse It!
While cavities may not become a thing of the past, it may be possible to stop the damage dead in its tracks. When a dentist sees the beginning of tooth decay, theres usually not much that can be done other than repair the damage. Some cavities, surprisingly, can reverse themselves in the early stages. New dental materials under development soon may be able to come to the rescue.
By understanding how tooth enamel forms and dental caries occurs, researchers at the Paffenbarger Research Center in Gaithersburg, Md., a collaboration between the American Dental Association Health Foundation and the National Institute of Standards and Technology are developing remineralization therapiesa form of tissue engineeringto help teeth regenerate. Teeth are constantly in motion, dissolving and rebuilding themselves with the calcium phosphate that is naturally present in saliva. One possibility now undergoing clinical trial is adding calcium phosphate to toothpaste, chewing gums and mouth rinses.
Researchers also are looking into the development of a smart material for fillings that could prevent cavities from recurring. When decay-producing acid starts to build up around the tooth or filling, cavity-fighting ingredients would be released to neutralize it. New materials also could reduce the need for root canals. Placing a sticky remineralizing material on the exposed pulp could speed up the natural repair process.
Pamela Houghtaling, (301) 975-5745
Turning Tragedy into a Better Understanding of Radiation Effects
In one of the worlds worst radiation accidents, the first Russian industrial nuclear facility, Mayak, poured about 80 million cubic meters (3 billion cubic feet) of liquid radioactive waste into the Techa River between 1949 and 1956. The residents of the villages along the river were exposed to both external irradiation (from contaminated river water, sediments and soils) and internal irradiation from the ingestion of contaminated foods.
Although tragic in its toll on life and health, the Mayak incident does offer one potentially positive outcome. Studies of the Techa River population could help medical researchers better define the health effects of radiation exposure. However, one critical unknown factor in this research has been getting an accurate measurement of the external radiation dose that the villagers received. Thats where the National Institute of Standards and Technology is lending a hand.
The most reliable method of performing the needed measurement is to examine teeth from exposed persons with electron paramagnetic resonance spectrometry. The EPR method can reconstruct the total (internal plus external) radiation dose accumulated and from this data, the separate external dose can be derived. Dental tissues from Techa River villagers have been archived and are being sent to the Ionizing Radiation Division of NISTs Physics Laboratory for EPR spectrometry analysis.
The NIST study should provide an independent source of data that can be used to validate this large-scale epidemiological study. These data also will be used
to validate current radiation protection standards and practices.
Michael Baum, (301) 975-2763
Party at Midnight on New Year's Eve . Again!
When the ball came down in New Yorks Times Square at midnight on last New Years Eve, most Americans thought they were celebrating the beginning of both the 21st century and a new millennium. However, the time and frequency experts at the National Institute of Standards and Technologykeepers of the official time standard for the United States, the NIST-F1 cesium fountain atomic clocksay think again.
Although there is no world or U.S. body with the authority to rule officially on this matter, the NIST timekeepers believe that the third millennium begins this Jan. 1. The first millennium, they say, started with the Year One and finished at the end of the year 1000. The second millennium then began at the start of the year 1001 and will conclude on Dec. 31 of this year. Therefore, the third millennium technically begins with the year 2001.
So, if you put away those party favors and dancing shoes after last Januarys blowout, get them out for another millennium welcome bash!
One thing about New Years Day thats official is determining the exact stroke of midnight. Get the precise time in any U.S. time zone on the Internet web site www.time.gov. Maintained by NIST and the U.S. Naval Observatory, the site provides a time reading accurate to within one second of the atomic time.
Collier Smith (Boulder), (303) 497-3198
The National Institute of Standards and Technology's 100th year of service to America began on March 3, 2000, and will culminate with our centennial anniversary one year later. For each month during this period, NIST Tech Beat will recall a significant event that occurred in the past century.
December Milestones Lined the Path to Closed Captioning on TV
Millions of Americans found television virtually meaningless until Dec. 10, 1976. On that date, the Federal Communications Commission voted to allow broadcasters to use closed captioning on a permanent basis for the deaf or severely hearing impaired. Perhaps the proudest people in the country that day were in Boulder, Colo.the researchers in NISTs Time and Frequency Division who pioneered the captioning technology.
The NIST system, called TvTime by its developers, was originally designed to allow TV networks to send encoded time and frequency data and text messages within their broadcast signal to affiliates. Transmissions were sent along an unused portion of the TV signal and only monitors with special decoders could reveal them.
At the suggestion of ABC-TV, the Boulder researchers decided to try using TvTime to carry captions for the deaf. The new system was first demonstrated in December 1971 with a test captioning of an episode of ABC-TVs The Mod Squad. In December 1972, the Secretary of Commerce petitioned the FCC to approve closed captioning on broadcast TV. Although defeated, the petition caught the attention of PBS engineers who asked NIST staff to join them in refining the technology.
Three years of work resulted in an improved and easier-to-use captioning system, the one approved by the FCC in December 1976. Four years later, the technology was honored with an Emmy Award.
Michael E. Newman, (301) 975-3025
The International Geophysical Year (1957-1958) coincided with a period of maximum sunspot activity, so researchers worldwide were keeping the Sun under continual visual and radio observation. All of the data were sent to the now-defunct World Warning Agency for processing to maintain a constant account of the state of the Sun. During periods of unusual solar behavior, NIST sent out alerts to scientists in 67 nations.
During the late 1940s and throughout the 1950s, NIST examined a number of natural polymers-such as cellulose, collagen and cotton-and the products derived from them-such as paper, leather and cloth-to determine their durability under various conditions. Included were tests on the fold endurance of paper, the water permeability of leathers and the abrasion resistance of textiles.
A precise measurement of the wavelength of the green spectral line for mercury-198 was proposed by NIST in 1951 as the "ultimate standard of length" to replace the platinum-iridium meter bar, the official standard since 1889. It was not accepted. Today, the meter is defined as the length of the path traveled by light in vacuum during a time interval of 1/299,792,458 of a second.