NIST Tech Beat - March 30, 2006

A rapid method for detecting and identifying very small numbers of diverse bacteria, from anthrax to E. coli, has been developed by scientists from the National Cancer Institute (NCI) and National Institute of Standards and Technology (NIST). Described in the March 28 issue of Proceedings of the National Academy of Sciences,* the work could lead to the development of handheld devices for accelerated identification of biological weapons and antibiotic-resistant or virulent strains of bacteria—situations where speed is essential.

Traditional ways of identifying infectious bacteria and their possible treatments can be time consuming and laborious, requiring the isolation and growth of the bacteria over many hours or even days. The new method speeds up the process by using fast-replicating viruses (called bacteriophages or phages) that infect specific bacteria of interest and are genetically engineered to bind to "quantum dots." Quantum dots are nanoscale semiconductor particles that give off stronger and more intense signals than conventional fluorescent tags and also are more stable when exposed to light. The method detects and identifies 10, or fewer, target bacterial cells per milliliter of sample in only about an hour.

The phages were genetically engineered to produce a specific protein on their surface. When these phages infect bacteria and reproduce, the bacteria burst and release many phage progeny attached to biotin (vitamin H), which is present in all living cells. The biotin-capped phages selectively attract specially treated quantum dots, which absorb light efficiently over a wide frequency range and re-emit it in a single color that depends on particle size. The resulting phage-quantum dot complexes can be detected and counted using microscopy, spectroscopy or flow cytometry, and the results used to identify the bacteria. The new method could be extended to identify multiple bacterial strains simultaneously by pairing different phages with quantum dots that have different emission colors.

The new method is more sensitive than conventional optical methods. It can count how many viruses are infecting a single bacteria cell and how many quantum dots are attached to a single virus. A provisional patent application was filed originally through NIST, and a non-provisional patent application was filed more recently through the National Institutes of Health, the parent agency of NCI. The NIST contributions to the work include experimental design and fluorescence imaging. Other authors are from NCI, NIH, SAIC-Frederick Inc. and the National Cancer Institute at Frederick.

* R. Edgar, M. McKinstry, J. Hwang, A.B. Oppenheim, R.A. Fekete, G. Giulian, C. Merril, K. Nagashima and S. Adhya. 2006. High sensitivity bacterial detection using biotin-tagged phage and quantum-dot nanocomplexes. Proceedings of the National Academy of Sciences. March 28.

Radio Frequency Identification (RFID) technology has been around for many years and is widely used to identify, track, and communicate information about items, products and even animals. An interdisciplinary team of researchers at the National Institute of Standards and Technology (NIST) is studying whether RFID technology can be used as a low cost, reliable means to track firefighters and other first responders inside buildings and help them navigate under hazardous conditions.

Typical RFID systems consist of tags, tag readers and application software. As the tagged products pass by a fixed reader they transmit data about the product and its location. The NIST researchers are looking at the “flip side.” They want to know whether inexpensive RFID tags placed inside buildings can help pinpoint the location of a first responder and provide local information to a small handheld device that includes an RFID reader and a navigation unit.

In place of GPS (Global Positioning System), which is unreliable inside most buildings, the researchers are evaluating whether inertial sensors such as accelerometers and gyroscopes can be used as part of the navigation system to help guide the first responder through the building. Navigation systems tend to “drift” over time and become increasingly inaccurate. When a first responder carrying the device encounters a tag, the system will make corrections by correlating the tag with its location. The reader’s interaction with a tag would be similar to using a “you are here” map in a shopping mall.

The research team’s plans over the next several years include defining the parameters needed to determine how many tags are needed and where they should be placed, developing a prototype RFID reader, integrating the reader and navigation hardware and software into a wireless network that can relay position information to others such as an incident commander, and testing a prototype system in a smoke-filled environment.

The NIST research team recently reported on the project at the eighth annual International Symposium on Advanced Radio Technologies. For more information, see http://www.antd.nist.gov/wctg/RFID/RFIDassist.htm.

NIST/ORNL Dedicate New Nuclear Medicine Lab

Positron Emission Tomography (PET) scan of brain with tumor

Shown above is a Positron Emission Tomography (PET) scan of a 62 year old man with a brain tumor. The irregular bright yellow and orange area in the lower left portion of the brain indicates the location of the tumor, which metabolizes glucose faster than normal cells.

View a high resolution version of this image.

Image credit: National Cancer Institute

The National Institute of Standards and Technology (NIST) is establishing a satellite facility at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tenn., to promote measurement accuracy for nuclear medicine imaging. In a dedication ceremony at the new laboratory today (March 30), NIST Director William Jeffrey and ORNL Director Jeff Wadsworth described the program, which is a pilot test for a planned series of such sites around the country.

NIST scientists will use the NIST/ORNL Nuclear Medicine Calibration Laboratory to prepare and measure radioactivity standards used for Positron Emission Tomography (PET). PET is a non-invasive technique that helps doctors diagnose diseases (such as cancer), plan medical treatment and measure the efficacy of therapies. An estimated 650,000 PET procedures were performed in 2003; the number is expected to reach as many as 2 million annually by 2010.

The procedure involves the injection of a low-dose radiopharmaceutical (such as glucose molecules with radioactive particles attached), which is metabolized in the part of the body being imaged. Specialized systems called PET scanners create an image of the location and intensity of the radiopharmaceutical in the body. A PET image can be used to differentiate between healthy and cancerous tissue. For instance, a tumor uses more glucose than normal tissue and therefore appears brighter in an image.

Prior to the injection, the amount of radioactivity is measured to ensure that the patient receives the prescribed dose. As the scanning technology has improved and image analysis has become more sophisticated, demand has grown for a more precise determination of the administered dose. The NIST/ORNL program, which is being carried out in cooperation with manufacturers of these radiopharmaceuticals, will provide direct traceability of these radioactivity measurements to national standards for the first time.

The NIST program needs to be carried out regionally because the short half-lives of most PET radiopharmaceuticals prevent shipment of standard test samples over long distances. Radioactive fluorine-18, for example, decays to half its originally produced total radioactivity in about 2 hours. Therefore, NIST is locating its satellite laboratories at key sites near manufacturers' distribution networks. The sites are selected based on location, capability, and reputation. ORNL has extensive expertise in radiation measurements; already operates a measurement traceability and testing program with NIST; and is licensed and capable of accepting, handling, and shipping radioactive materials. The NIST program will be expanded to other sites in the future.

Media Contact:
Laura Ost, laura.ost@nist.gov, (301) 975-4034

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Quality Standards Issued For Testing Herbal Products

The National Institute of Standards and Technology (NIST) has issued the first suite of Standard Reference Materials (SRMs) in a planned series of reference materials for botanical dietary supplements.

The dietary supplement industry has exploded in the past decade to about 29,000 products, with about 1,000 new products introduced each year, according to the Food and Drug Administration (FDA). In 2001 NIST began working with the FDA and the National Institutes of Health's Office of Dietary Supplements (NIH/ODS) on a series of SRMs of popular botanical dietary supplements. Manufacturers can use these materials for quality control, and researchers can use them to ensure that their laboratory analyses of supplements are accurate. Products such as botanical supplements, that have been derived from extracts of plant materials are challenging to analyze accurately because of their complex sample matrices.

The new NIST reference materials were designed primarily for quality control of supplements containing ephedra, a plant once widely used in herbal weight-loss products. Ephedra products were pulled from the market by the FDA in 2004 after being linked to cardiovascular problems, but the new test materials remain valuable both to assure that new products are not adulterated with ephedra and because they also can be used to improve several other key measurements in other botanical supplements, including concentrations of potentially toxic heavy metals.

The new reference materials represent several different forms of ephedra and include powdered plant material (SRM 3240), a ground solid oral dosage form (SRM 3243), and a protein powder (SRM 3244). The materials are certified for their concentrations of the ephedrine alkaloids and potentially toxic elements (including arsenic, cadmium, lead and mercury). SRM 3243 also provides certified values for synephrine (a compound in some of the "ephedra-free" weight-loss products) and caffeine. SRM 3244 adds values for caffeine, theobromin, theophylline, and nutrients including fat, protein, carbohydrate, individual fatty acids and amino acids, vitamins and nutritive elements.

Future dietary supplement SRMs will include: Ginkgo biloba, saw palmetto, bitter orange, carrot extract, green tea, blueberries, cranberries, bilberries and St. John's wort. For further information visit www.nist.gov/srm.

Air is a great insulator—except when it becomes a conductor. Under the right conditions, miniature lightning bolts of electricity will “arc” through the air between two electrically conducting points. Engineers can accurately predict how this happens on the macroscopic scale—when electricity from a downed power line, for example, jumps to a nearby metal object—but less is known about the process at the micro scale.

To help quantify the process, a new device and technique have been developed at the National Institute of Standards and Technology (NIST) for measuring “breakdown” voltage—the voltage required to produce electrical arcs when electrodes are 400 nanometers to 45 micrometers apart. The advance could be useful in microelectronics, such as in the design of microelectro-mechanical systems (MEMS), in which arcing could cause device failure. The NIST work may also be useful in the design of larger scale electrical systems for automobiles.

The device (a novel capacitor design), described in the March issue of Review of Scientific Instruments,* includes two horseshoe-shaped circuits that each end in two smooth rectangular electrodes. The distance between electrodes of different circuits can be varied in micrometer increments. To determine the breakdown voltage for each distance, the researchers changed the amount of voltage applied and measured the resulting current flowing between the two electrodes. For example, NIST researchers found that, at an electrode separation of 7 micrometers, the breakdown voltage is 185 volts. Conventional wisdom for electrical behavior at the macroscale says that at least 360 volts are needed.

Air insulates at low electric fields because electrons are scattered by nitrogen and oxygen atoms, thereby slowing them down. But at higher fields, the electrons gain enough energy to knock additional electrons out of the molecules in the air, and a current can form. Electrode shape is also a factor; sharp points produce electric fields that vary with position, and are therefore more likely to cause problems than blunt shapes. The NIST capacitor enables very accurate measurements because it produces nearly parallel electric fields and has very smooth electrodes made of thin films of gold only 70 nm thick (even slight surface roughness amplifies electric fields).

*E. Hourdakis, B.J. Simonds, and N.M. Zimmerman. 2006. Sub-micron gap capacitor for measurement of breakdown voltage in air. Review of Scientific Instruments. March.

Engineers and information specialists from government, industry and academia agreed this month at a National Institute of Standards and Technology (NIST) workshop* that immediate action is needed to keep vast amounts of digital knowledge from disappearing into cyberspace or becoming in 200, or even 20 years, as incomprehensible as the markings on Babylonian cuneiform tablets.

According to estimates offered at the conference, the world churns out new digital information equivalent to the entire collection of the U.S. Library of Congress every 15 minutes. Such a proliferation of information in digital format, occurring almost 100 times a day, adds up to approximately five exabytes (five quintillion bytes or five billion gigabytes) a year. Unlike information stored on paper, however, this digital information can disappear almost instantaneously. Major historical artifacts such as original homepages of breakthrough e-commerce sites are already gone. Photographic records, stored digitally on disks, are in jeopardy of decay in as short a time as five years. At the same time, the rapid pace of technological change, itself, makes it difficult to understand documents preserved in earlier formats.

Participants agreed on the need to build a business case to offer companies in areas such as manufacturing, health care, life sciences, law and defense an incentive to invest in digital archiving. Such a study would demonstrate how access to archived information is critical to trace design rationale in cases of failure, document engineering changes, support product life-cycle use, investigate accidents, defend against patent infringement, compare new works with earlier versions, facilitate mergers and acquisitions. Arguments for archiving everything from engineering discussions, e-mails, and CAD models to design and production logs and manufacturing process plans would be presented. The study would also explore the cost of not archiving such information by estimating avoidable expenses for errors, recreating the data or reverse engineering, retesting, training, education and lost business.

The workshop reviewed current digital archival techniques as well as prospects for future software and standards in the area. The conference participants also discussed the possibility of collaboration on future digital archiving research projects. A report of the workshop is expected in late spring.

*”Long Term Knowledge Retention Workshop”, March 15-16,”2006 Interoperability Week at NIST”. Gaithersburg, Md.

Physicists at Harvard University, George Mason University and the National Institute of Standards and Technology (NIST) have discovered new quantum effects in ultracold gases that may lead to improved understanding of electrical conductivity in metals.

In work presented at the March meeting of the American Physical Society* in Baltimore, Md., the researchers calculated the properties of an “artificial crystal” of ultracold atoms in a lattice formed by intersecting laser beams. The wave patterns in the laser light form the equivalent of row upon row of stadium seating for the atoms, an appropriate analogy given that the work was debuted during the height of college basketball’s "March Madness" tournament.

In metals like copper, two mutually exclusive types of effects tend to slow down the flow of electrons and reduce electrical conductivity, namely disorder in the crystal structure or blocking of electrons by other electrons that are already occupying a given space.

“In March Madness terms,” says NIST physicist Charles Clark, “fans who arrive early to an empty stadium can move relatively quickly down any row unless they encounter a railing, wall or other barrier (crystal disorder) but once the game begins a fan’s movements are constrained along rows by other fans already occupying seats (electron blocking).” Even though Phillip Anderson and Sir Neville Mott won the Nobel Prize in 1977 for explaining these phenomena in metals, it has been difficult to observe the effects in real materials.

By using equations dictated by the laws of quantum mechanics (the rules obeyed by nature’s smallest particles), the researchers were able to simulate gases in optical lattices as models for materials that haven’t been created yet. They found that under certain conditions electron blocking occurs even when the lattice would ordinarily be a good conductor. They also found that interference effects between the wave properties of ultracold atoms in the lattice form natural fractal patterns—that is, no matter how many times the pattern is magnified, new patterns of detail are revealed.

* A.M. Rey, I.I. Satija, and C.W. Clark, “Quantum coherence of hard-core bosons and fermions in one dimensional quasi-periodic potentials: superfluid, Mott, and glassy phases,” Delivered March 15, 2006 at the American Physical Society meeting, Batimore, Md.. Available at http://arxiv.org/PS_cache/cond-mat/pdf/0601/0601307.pdf (.pdf; download Acrobat Reader).

To keep current with changing technology, the National Institute of Standards and Technology (NIST) is proposing several changes to the Digital Signature Standard (DSS). First issued in 1994 and updated in 1998 and 1999, DSS is used widely by federal agencies and numerous private-sector organizations to confirm the identity of a document signer and to verify the integrity of electronic data. Currently, the standard includes three algorithms for generating digital signatures: the Digital Signature Algorithm (DSA), RSA and the Elliptic Curve Digital Signature Algorithm (ECDSA).

Digital signature algorithms require keys to generate secure signatures. With advances in technology, the size of these keys must be increased to provide adequate security. For DSA, the current version authorizes the use of key sizes of 512 to 1024 bits. Key sizes of 1024 now are considered the minimum acceptable level for security of digital signatures.

The draft Federal Information Processing Standard (FIPS) 186-3 allows the use of 1024, 2048 and 3072-bit keys for DSA and RSA, and continues to recommend the ECDSA. FIPS 186-3 also proposes allowing federal agencies to use Public Key Cryptography Standard (PKCS) 1 to generate RSA digital signatures. PKCS 1 was developed by RSA Security, Bedford, Mass.

The draft FIPS 186-3 with the proposed changes is available at http://csrc.nist.gov/publications/drafts.html. Comments should be sent by June 12 to Elaine Barker at elaine.barker@nist.gov, or mailed to Chief, Computer Security Division, Information Technology Laboratory, Attention: Comments on Draft FIPS 186-3, 100 Bureau Dr., Stop 8930, NIST, Gaithersburg, Md., 20899-8930.

Ground, aerial and aquatic emergency response robots from across the country will face real-life challenges April 4-6 in tests of their life-saving skills at Texas A&M University’s "Disaster City" in College Park, Texas.

The event, hosted by Texas A&M Engineering Extension Service and the local Federal Emergency Management Agency (FEMA) Task Force, is the second in a series of evaluation exercises conducted by the National Institute of Standards and Technology (NIST) for urban search and rescue robots. The program is sponsored by the Department of Homeland Security’s Science and Technology Directorate.

Emergency responders will have an opportunity to see urban search-and-rescue robots in action while helping robot developers refine ideas and understand real-life robot performance requirements. NIST researchers expect to use data collected at the event to help develop performance standards and usage guides, including advice on which robots are best suited for specific emergency situations.

Disaster City, adjacent to the Texas A&M campus, is a 52-acre training facility designed to deliver the full array of skills and techniques needed by urban search-and-rescue professionals, including full-scale collapsible structures that replicate community infrastructure, including a strip mall, office building, industrial complex, assembly hall/theater, single-family dwelling, train derailments and three active rubble piles.

The National Institute of Standards and Technology (NIST) will host a workshop at its headquarters in Gaithersburg, Md., on April 26 to help federal agencies comply with FISMA (Federal Information Security Management Act) through the development of uniform requirements for security assessment service providers. FISMA requires all federal agencies to develop, document and implement agency-wide information security programs including evaluation of the effectiveness of its information security policies, procedures, practices, and security controls to provide security for the information and information systems that support the operations and assets of the agency.

NIST established a three-phase project to help federal agencies implement FISMA. In Phase I, NIST developed a suite of security standards and guidelines providing baseline security requirements and controls required by FISMA. Phase II, and this workshop, will focus on developing a program for credentialing public and private sector organizations to conduct information security assessments of federal information systems based on demonstrated competence in the security standards and guidelines developed in Phase I.

For more information on the workshop, see www.nist.gov/public_affairs/confpage/060426.htm.

National Institute of Standards and Technology (NIST) Director William Jeffrey has appointed Daniel J. Chenok, a prominent leader in the information technology industry, as the new chair of the Information Security and Privacy Advisory Board. The Board advises NIST on emerging managerial, technical, administration and physical safeguard issues related to information security and privacy issues.

Chenok is vice president and director, Business Solutions and Offerings, SRA International, Inc., Fairfax, Va. Chenok is responsible for developing and managing SRA's offerings and solutions that support the company's civil, defense and command and control, and communications and intelligence sectors. Prior to assuming his current role, Chenok served as SRA’s director of policy and management strategies. In 2005, Federal Computer Week named Chenok to its list of 100 leaders who played pivotal roles in the federal information technology community during 2004.

Before joining SRA in January 2004, Chenok served in the Office of Management and Budget (OMB) and was responsible for oversight of federal policies in many IT-related areas including electronic government, computer security, and privacy.

The Information Security and Privacy Advisory Board was established by the Computer Security Act of 1987 and amended by the Federal Information Security Management Act of 2000 to advise NIST, the Secretary of Commerce and the Director of OMB on information security and privacy issues pertaining to federal information systems. The board annually reports its findings to the Secretary of Commerce, the Director of OMB, the Director of the National Security Agency and the appropriate committees of the Congress.

Collins Named to Head NIST Technology Services

Belinda L. Collins, an expert in both the technical and policy related aspects of standards development, has been promoted to director of Technology Services at the National Institute of Standards and Technology (NIST).

A research psychologist by training, Collins specialized in studies of human responses to lighting. She was instrumental in the development of national and international standards that range from specifications for visibility and understandability of exit signs and safety symbols to color-rendering standards for meat and poultry inspection. Collins has served in several managerial and policy positions during her 32-year career at NIST. In recent years, she has concentrated largely on standards issues that affect competitiveness and trade and on efforts to foster greater government use of private sector standards in regulations and for procurement.

Collins was the chair of the federal Interagency Committee on Standards Policy when the law directing federal agencies to use standards in their regulatory and procurement actions and giving NIST coordination responsibilities was passed, and she serves on the Board of Directors of the American National Standards Institute. She has received numerous awards for her work inside the government and with private sector organizations.

Since February 2004, Collins had been serving as acting director of Technology Services. The unit provides U.S. business and other organizations with measurements, tests, calibrations, technical data and other resources and services developed at NIST. She succeeds Richard Kayser, who recently was named director of the NIST Materials Science and Engineering Laboratory. For more information on Technology Services, go to: http://ts.nist.gov/