NIST Tech Beat - Sept. 14, 2006

Researchers from the National Institute of Standards and Technology (NIST) and North Carolina State University (NCSW) have demonstrated that a commonly prescribed antidepressant can interfere with the reproductive cycle of freshwater mussels—at least in a controlled setting. The research, presented this week at the national meeting of the American Chemical Society*, was conducted to better understand the environmental impact of pharmaceuticals in waste water.

More and more studies are turning up evidence of common drugs and their breakdown products in the nation’s waterways (see NIST Tech Beat, www.nist.gov/public_affairs/techbeat/tb2005_1222.htm#drugs), raising concerns about potential health impacts for both humans and animals from low-level but continuous exposure to the chemicals. NIST and NCSU researchers at the Hollings Marine Laboratory (Charleston, S.C.) examined the effect of fluoxetine, a selective serotonin reuptake inhibitor (SSRI) on a native freshwater mussel (Elliptio complanata). Fluoxetine, sold under the trade name Prozac™, is one of the most heavily prescribed antidepressants in the United States. In humans, it acts to increase the levels of serotonin at nerve synapses, relieving depression and associated illnesses. But for a number of aquatic species, serotonin moderates the reproductive system—and has been used to artificially induce spawning in bivalves.

At laboratory test concentrations, they found, fluoxetine caused female mussels carrying larvae to release them prematurely, and often, before they were viable, disrupting their reproductive cycle. Approximately 70 percent of the almost 300 species of North American freshwater mussels are considered vulnerable to extinction or already extinct.

The finding also raises questions about the effect of fluoxetine on other aquatic species that share similar endocrine mechanisms. The research team currently is gathering environmental samples from local waters and sediments to compare environmental concentrations with their findings.

*R. Heltsley, W.G. Cope, R. Bringolf, C. Eads and D. Shea. Prozac elicits spawning in native freshwater mussels. Presented at the 232nd ACS National Meeting, San Francisco, Calif., Sept. 13, 2006.

The National Institute of Standards and Technology (NIST) has issued three new reference materials to support researchers studying the properties of commercially important zeolites.

First described in the 18^th century, zeolites have seen increasing use in industry and commerce from cat litter to industrial catalysts and “molecular sieves.” Zeolites belong to class of materials called alumino-silicates whose crystal structures form highly porous, nanoscale “cages” that can filter and trap small molecules. Naturally occurring zeolites are mined and widely used as absorbents in products such as cat litter. Tailored synthetic zeolites have a wide variety of more specialized applications, such as in laundry detergents (where they replace pollution-causing phosphates), and as catalysts in oil refineries. Because they can be designed with pores that pass only molecules of a certain size and shape, zeolites have excited considerable interest as molecular sieves for chemical separations—they are used in oxygen generation systems for medical oxygen, for example.

It is often extremely difficult to make precision measurements of key chemical characteristics for zeolites because they are ferociously hygroscopic. Humidity must be precisely controlled—and specified—to make meaningful measurements of the elemental content, for example. This has made it difficult to compare experimental results between different labs.

To provide a common basis for research on three widely used industrial zeolites, NIST has issued reference materials for Zeolite Y (RM 8850), Zeolite A (RM 8851) and Ammonium ZSM-5 Zeolite (RM 8852). While these materials do not come with the certified property values and uncertainty estimates furnished with NIST Standard Reference Materials (SRMs), these RMs do provide a common source of zeolite materials for measurement comparisons. Reference and information values are provided for major and trace element content, key atomic ratios, enthalpy of formation, unit cell parameters and particle size distributions.

The National Institute of Standards and Technology (NIST), in cooperation with the External RNA Controls Consortium (ERCC), has awarded a contract to Commonwealth Biotechnologies, Inc. (CBI, Richmond, Va.) to produce suites of RNA test samples that will be evaluated in two rounds of a collaborative study through this winter. The study represents a major milestone in the ERCC’s program to develop a standard set of RNA control samples that will be used to assess the performance of gene expression experiments.

Gene expression, a measure of the activity of specific genes under various conditions, is a cornerstone of modern bioscience. Gene expression is often measured across entire genomes—measuring as many as 50,000 different chemical entities simultaneously—presenting a unique measurement challenge in assessing the validity of experimental results. The approximately 90 companies, universities and federal laboratories in the ERCC are developing materials and tools that can be used to benchmark the most widely used tools for gene expression, including quantitative, real-time reverse transcriptase polymerase chain reaction (QRT-PCR) and DNA microarrays. NIST is a founding member and host of the consortium.

NIST has assembled a sequence library of approximately 160 sequences that are intended to act as controls. Many of these are synthetic constructs that mimic mammalian genes, but which can be found in no known genome*. CBI will synthesize mixtures of these sequences as RNA for use in the collaborative study, which will establish a “reference set" of RNA controls. The eight registered testing sites represent companies that manufacture microarrays and reagents and one government laboratory that makes arrays: Affymetrix Inc. (Santa Clara, Calif.), Agilent Technologies Inc. (Santa Clara, Calif.), Applied Biosystems (Foster City, Calif.), GE Healthcare (Chalfont St. Giles, U.K.), Illumina Inc., San Diego, Calif.), the National Institute of Allergy and Infectious Diseases (NIH), Qiagen N.V. (The Netherlands) and Roche Molecular Systems (Pleasanton, Calif.)

“The ultimate goal of the collaborative study is to determine a set of sequences that will give reliable, repeatable values across a variety of gene expression assay techniques,” notes Marc Salit, NIST’s representative on the ERCC, “That will give the research community something that they’re all interested in—a solid, quantitative way to establish performance and gain confidence in their data, regardless of platform or assay.” The ERCC plans to announce the results of the collaborative study in a public meeting in September 2007.

*The sequences collected in the library to date were contributed by NIST and the Hollings Marine Laboratory (Charleston, S.C.), the National Institute of Allergy and Infectious Diseases, Stanford University, Affymetrix, Invitrogen Corporation (Carlsbad, Calif.), and Atactic Technologies Inc. (Houston, Texas).

The National Institute of Standards and Technology (NIST), the University of Maryland (UM) and the National Security Agency (NSA) announced this week the creation of a joint research institute designed to advance quantum physics research and to exploit this knowledge to transform quantum technology from an exciting promise to practical reality.

The institute will be located on the University of Maryland campus in College Park. It will have an annual budget of approximately $6 million and a staff of about 20 scientists, half from the university and half from NIST. The staff will include experts in atomic physics, condensed matter and quantum information, including William D. Phillips, the 1997 Nobel laureate in physics, who is both a NIST Fellow and a Distinguished University Professor of Physics at Maryland. Co-directors for the institute are Christopher J. Lobb, professor of physics at Maryland, and Carl J. Williams, chief of the NIST Atomic Physics Division.

The three participating institutions have a shared history of collaboration and cooperation in education, research and public service. The new institute is the latest of several major new collaborative efforts between UM and NIST initiated since the two institutions signed an agreement in 2003 to broadly expand research collaborations and professional linkages.

The JQI’s three primary scientific disciplines are: atomic, molecular and optical physics (such as ultra-cold atomic gases, matter wave optics, quantum optics and optical lattices), a major area of expertise at NIST and a growing strength at UM; condensed matter physics (such as quantum dots and superconductivity), an area of expertise at UM and the NSA’s Laboratory for Physical Sciences; and quantum information science (such as quantum measurement theory, quantum computation and quantum communication), areas of expertise at both NIST and UM.

A new design for a microwave oscillator that is smaller, simpler, and produces clearer signals at a single frequency than comparable devices has been invented at the National Institute of Standards and Technology (NIST). Applications could include homeland security (e.g., surveillance of radio traffic for anomalous signals, or high-resolution digital imaging radar on unmanned aircraft), telecommunications (e.g., maintaining separation between frequencies in high-bandwidth networks), and perhaps even consumer devices (e.g., satellite television downlinks).

A patent was issued recently* for the NIST oscillator, which is about the size of a roll of 35 mm camera film. NIST researchers have built five prototypes on test fixtures, which offer several-orders-of-magnitude reductions in various types of self-generated signal interference, or noise, compared to typical commercial oscillators, resulting in improved frequency stability, according to David Howe, one of the inventors. In addition, the simple design reduces costs and improves reliability, while consuming less power than other oscillators of comparable signal purity. The small size could be an advantage on some surveillance platforms.

Microwave oscillators are used as reference or clock signals in many high-precision technologies. Through control of temperature and other variables, the oscillators produce a desired signal at one narrowly defined frequency while suppressing random, electronically induced “noise” generated by components. In the best microwave oscillators, the signal typically is amplified inside a metal cavity containing a solid insulating material that internally sustains microwaves and radio waves with minimal loss, especially at cryogenic temperatures, an expensive and complex design. By contrast, the NIST oscillator uses an ultra-stiff ceramic manifold that supports a single frequency with either a vacuum or air as the insulating medium.

The NIST device operates at high signal power (many watts) without the noise penalty found in the conventional design just described. The technique maintains such a stable frequency that it can overcome or compensate for self-generated noise produced by components such as amplifiers that sustain oscillation. NIST researchers continue to work on improvements, hoping to make the technology more tolerant of vibrations such as those from aircraft, field radars, and even sub-audible vibrations in buildings.

*United States Patent US007075378B2. High spectral purity microwave oscillator using air-dielectric cavity, D.A. Howe, A.S. Gupta, C. Nelson, F.L. Walls, July 11, 2006.

Experts in manufacturing processes, measurement science and tools, and computational methods will meet Oct. 17-19, 2006, in Gaithersburg, Md., to set research goals and chart other next steps necessary to convert progress in nanotechnology into safe, practical products.

Organized by the federal Interagency Working Group on Manufacturing Research and Development (R&D), the Workshop on Instrumentation, Metrology, and Standards for Nanomanufacturing will feature presentations by R&D managers in a variety of industries, including electronics, aerospace, chemical and paper. Facilitated break-out sessions will be devoted to identifying key technical challenges that stand in the way of achieving safe, reliable and cost-effective manufacturing methods needed to make products envisioned for markets and applications ranging from biotechnology and health care to advanced materials and consumer electronics.

Workshop discussions will yield recommendations for future research to enable the manufacture of real-world nanotechnology products. These will help to guide the interagency working group, which was established by the National Science and Technology Council, to coordinate federal R&D efforts that respond to economic or other national needs and to help U.S. manufacturers leverage these efforts into a competitive technological advantage.

The workshop will conclude with an industry-led Nanotechnology/Nanomanufacturing Stakeholder Meeting, which will focus specifically on predictive modeling capabilities and elements of a nanotechnology design infrastructure.

Attendance is limited. The registration deadline is Oct. 1. To learn more about the workshop and to register, go to www.mel.nist.gov/nano.htm.

The workshop is sponsored by NIST, the National Science Foundation, and the Office of Naval Research.

TV shows such as "CSI: Crime Scene Investigation" have popularized the role of forensic science in solving crimes. Now, computer security experts at the National Institute of Standards and Technology have issued a guide to help organizations use similar techniques to troubleshoot operational problems, investigate computer security incidents and recover from accidental system damage.

The guide recommends a four-step process for digital forensics: (1) identify, acquire and protect data related to a specific event; (2) process the collected data and extract relevant pieces of information from it; (3) analyze the extracted data to derive additional useful information; and (4) report the results of the analysis. Lessons learned during the forensic process should be incorporated in future forensic efforts.

The guide contains eight different scenarios, including a denial of service attack and an unknown wireless access point that can be used by organizations conducting tabletop exercises. The scenarios include general questions that can be applied to most scenarios as well as additional scenario-specific questions, such as how particular types of forensic tools or techniques might be used.

Created primarily for incident response teams; system, network, and security administrators; and computer security program managers, the guide recommends that others in the organization, including legal advisors and physical security staff, also participate in digital forensic activities.

(Return to NIST News Page)

Editor: Michael Baum

Date created: 9/14/06
Date updated: 9/14/06
Contact: inquiries@nist.gov