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Tech Beat - June 30, 2009

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Editor: Michael Baum
Date created: January 5, 2011
Date Modified: January 5, 2011 
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Genetically Engineered Mice Yield Clues to ‘Knocking Out’ Cancer

Deleting two genes in mice responsible for repairing DNA strands damaged by oxidation leads to several types of tumors, providing additional evidence that such stress contributes to the development of cancer. That’s the conclusion of a recent study* in DNA Repair by researchers at the National Institute of Standards and Technology (NIST), Oregon Health and Science University (OHSU) and the New York University School of Medicine (NYUSM).

section of lung tissue from a mouse

Section of lung tissue from a double knockout mouse, stained to show lung tumors. Mice lacking both the neil1 and nth1 genes were particularly prone to pulmonary and liver tumors during their second year.

Credit: Teebor, NYU
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Although all cells need oxygen to survive, the element also can be stressful to cells and their components—particularly DNA—as part of “reactive species” in the environment, such as free radicals and peroxides. The damage levied on DNA by these compounds can include lesions, breaks, cross-links and deletions—errors in our normal genetic codes that, if left unchecked, may accelerate the aging process and increase susceptibility to several disease states. In humans, DNA repair genes produce enzymes called DNA glycosylases that excise sections of DNA strands already modified by oxidative stress, and thus protect the genetic material.

One of these repair genes, neil1, was identified and characterized in 2002 by Sankar Mitra and his team at the University of Texas Medical Branch in collaboration with NIST researchers Miral Dizdaroglu and Pawel Jaruga. The gene produces a DNA repair protein, NEIL1 that is nearly identical in humans and mice. Therefore, a mouse serves a perfect model for studying the biological function of the neil1 gene in both species.

To do this, OHSU researchers under R. Stephen Lloyd genetically engineered mice without the neil1 gene (known as neil1 knockout mice). During their first 6-10 months of life, the majority of male mice developed severe obesity, dyslipidemia (abnormal levels of lipids in the blood), fatty liver disease and hyperinsulinemia (excess levels of circulating insulin in the blood). In humans, these disorders are collectively known as metabolic syndrome, a condition that affects more than 40 million persons in the United States.

In collaboration with Dr. Lloyd’s group, a second research team under George W. Teebor at NYUSM engineered mice that were missing either the neil1 or the nth1 gene (nth1 encodes for another DNA glycosylase, the NTH1 protein) or both these genes. These latter are known as neil1/nth1 double knockouts. NIST’s Dizdaroglu and guest researchers Pawel Jaruga and Güldal Kirkali found that both types of knockout mice exhibited significant accumulation of two lesions called formamidopyrimidines in the DNA of the liver, kidney and brain. This indicates that there was a lack of DNA repair in these organs.

During the second year of life, both types of mice also developed pulmonary and hepatocellular (liver cell) tumors. Double knockout mice had a higher incidence of tumors than the single knockouts.

The researchers state that their results emphasize the role of DNA repair in preventing carcinogenesis. The work may lead to the development of new measurement methods and reference materials for accurate and reproducible assessments of DNA damage and repair and contribute to understanding the role of oxidatively induced DNA damage and its repair in carcinogenesis. Future studies will focus on the role of NEIL1 in disease processes.

* M.K. Chan, M.T. Ocampo-Hafalla, V.Vartanian, P. Jaruga, G. Kirkali, K.L. Koenig, S. Brown, R. S. Lloyd, M. Dizdaroglu and G.W. Teebor. Targeted deletion of the genes encoding NTH1 and NEIL1 DNA N-glycosylases reveals the existence of novel carcinogenic oxidative damage to DNA. DNA Repair, Vol. 8, No. 7, pp. 786-794 (July 4, 2009).

Media Contact: Michael E. Newman, michael.newman@nist.gov, 301-975-3025

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NIST Develops Novel Ion Trap for Sensing Force and Light

Miniature devices for trapping ions (electrically charged atoms) are common components in atomic clocks and quantum computing research. Now, a novel ion trap geometry demonstrated at the National Institute of Standards and Technology (NIST) could usher in a new generation of applications because the device holds promise as a stylus for sensing very small forces or as an interface for efficient transfer of individual light particles for quantum communications.

NIST stylus trap

The NIST "stylus trap" can hold a single ion (electrically charged atom) above any of the three sets of concentric cylinders on the centerline. The device could be used as a stylus with a single atom "tip" for sensing very small forces or an interface for efficient transfer of individual light particles for quantum communications.

Credit: Maiwald, NIST
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The “stylus trap,” built by physicists from NIST and Germany’s University of Erlangen-Nuremberg, is described in Nature Physics.* It uses fairly standard techniques to cool ions with laser light and trap them with electromagnetic fields. But whereas in conventional ion traps, the ions are surrounded by the trapping electrodes, in the stylus trap a single ion is captured above the tip of a set of steel electrodes, forming a point-like probe. The open trap geometry allows unprecedented access to the trapped ion, and the electrodes can be maneuvered close to surfaces. The researchers theoretically modeled and then built several different versions of the trap and characterized them using single magnesium ions.

The new trap, if used to measure forces with the ion as a stylus probe tip, is about one million times more sensitive than an atomic force microscope using a cantilever as a sensor because the ion is lighter in mass and reacts more strongly to small forces. In addition, ions offer combined sensitivity to both electric and magnetic fields or other force fields, producing a more versatile sensor than, for example, neutral atoms or quantum dots. By either scanning the ion trap near a surface or moving a sample near the trap, a user could map out the near-surface electric and magnetic fields. The ion is extremely sensitive to electric fields oscillating at between approximately 100 kilohertz and 10 megahertz.

The new trap also might be placed in the focus of a parabolic (cone-shaped) mirror so that light beams could be focused directly on the ion. Under the right conditions, single photons, particles of light, could be transferred between an optical fiber and the single ion with close to 95 percent efficiency. Efficient atom-fiber interfaces are crucial in long-distance quantum key cryptography (QKD), the best method known for protecting the privacy of a communications channel. In quantum computing research, fluorescent light emitted by ions could be collected with similar efficiency as a read-out signal. The new trap also could be used to compare heating rates of different electrode surfaces, a rapid approach to investigating a long-standing problem in the design of ion-trap quantum computers.

Research on the stylus trap was supported by the Intelligence Advanced Research Projects Activity.

* R. Maiwald, D. Leibfried, J. Britton, J.C. Bergquist, G. Leuchs, and D.J. Wineland. 2009. Stylus ion trap for enhanced access and sensing. Nature Physics, published online June 28.

Media Contact: Laura Ost, laura.ost@nist.gov, 303-497-4880

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Unexpectedly Long-Range Effects in Advanced Magnetic Devices

A tiny grid pattern has led materials scientists at the National Institute of Standards and Technology (NIST) and the Institute of Solid State Physics in Russia to an unexpected finding—the surprisingly strong and long-range effects of certain electromagnetic nanostructures used in data storage. Their recently reported findings* may add new scientific challenges to the design and manufacture of future ultra-high density data storage devices.

NIST MOIF (Magneto-optic imaging film) technique

NIST MOIF (Magneto-optic imaging film) technique is unique in being able to image magnetic domains in real time while they are forming, growing and disappearing. Bright and dark regions represent stray magnetic fields as domains change. Here a series of MOIF images shows reversal of domains in a ferromagnetic film having a grid of antiferromagnetic strips on top as the external field increases to the right.

Credit: Shapiro, NIST
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The team was studying the behavior of nanoscale structures that sandwich thin layers of materials with differing magnetic properties. In the past few decades such structures have been the subjects of intense research because they can have unusual and valuable magnetic properties. The data read heads on modern high-density disk drives usually exploit a version of the giant magnetoresistance (GMR) effect, which uses such layered structures for extremely sensitive magnetic field detectors. Arrays of nanoscale sandwiches of a similar type might be used in future data storage devices that would outdo even today’s astonishingly capacious microdrives because in principle the structures could be made even smaller than the minimum practical size for the magnetic islands that record data on hard disk drives, according to NIST metallurgist Robert Shull.

The key trick is to cover a thin layer of a ferromagnetic material, in which the magnetic direction of electrons, or “spins,” tend to order themselves in the same direction, with an antiferromagnetic layer in which the spins tend to orient in opposite directions. By itself, the ferromagnetic layer will tend to magnetize in the direction of an externally imposed magnetic field—and just as easily magnetize in the opposite direction if the external field is reversed. For reasons that are still debated, the presence of the antiferromagnetic layer changes this. It biases the ferromagnet in one preferred direction, essentially pinning its field in that orientation. In a magnetoresistance read head, for example, this pinned layer serves as a reference direction that the sensor uses in detecting changing field directions on the disk that it is “reading.”.

Researchers have long understood this pinning effect to be a short-range phenomenon. The influence of the antiferromagnetic layer is felt only a few tens of nanometers down into the ferromagnetic layer—verticallly. But what about sideways? To find out, the NIST/ISSP team started with a thin ferromagnetic film covering a silicon wafer and then added on top a grid of antiferromagnetic strips about 10 nanometers thick and 10 micrometers wide, separated by gaps of about 100 micrometers. Using an instrument that provided real-time images of the magnetization within grid the structure, the team watched the grid structure as they increased and decreased the magnetic field surrounding it.

What they found surprised them.

As expected, the ferromagnetic material directly under the grid lines showed the pinning effect, but, quite unexpectedly, so did the uncovered material in regions between the grid lines far removed from the antiferromagnetic material. “This pinning effect extends for maybe tens of nanometers down into the ferromagnet right underneath,” explains Shull, “so you might expect that there could be some residual effect maybe tens of nanometers away from it to the sides. But you wouldn’t expect it to extend 10 micrometers away—that’s 10 thousand nanometers.” In fact, the effect extends to regions 50 micrometers away from the closest antiferromagnetic strip, at least 1,000 times further than was previously known to be possible.

The ramifications, says Shull, are that engineers planning to build dense arrays of these structures onto a chip for high-performance memory or sensor devices will find interesting new scientific issues for investigation in optimizing how closely they can be packed without interfering with each other.

* Y.P. Kabanov, V.I. Nikitenko, O.A. Tikhomirov, W.F. Egelhoff, A.J. Shapiro and R.D. Shull. Unexpectedly long-range influence on thin-film magnetization reversal of a ferromagnet by a rectangular array of FeMn pinning films. Physical Review B 79, 144435, 2009. DOI: 10.1103/PhysRevB.79.144435.

Media Contact: Michael Baum, michael.baum@nist.gov, 301-975-2763

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NIST Summer School Passes the Neutron Science Torch

What do the mystery of how proteins fold, the unexpected behavior of nanoparticles, and the key to making hydrogen fuel cells have in common? All can be investigated with beams of slow-moving neutrons—and scientists at the National Institute of Standards and Technology (NIST) took a week this summer to teach the next generation of scientists how to use these beams to explore innovative materials.

summer students at NIST explore the NCNR

Khiza Mazwi, a student from the University of Southern California, replaces a sample in the spin echo spectrometer while other participants in the NCNR summer school look on.

Credit: Boutin, NIST
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Thirty-six students came to NIST’s Center for Neutron Research (NCNR) to cut their teeth on some of the world’s finest tools for probing the intricacies of small, valuable materials. The NCNR Summer School, now in its 15th year, provides undergraduate and graduate students from the United States and abroad with hands-on experiences with the NCNR’s sensing equipment, which harnesses cold, or slow, neutrons to illuminate the inner workings of objects just a few nanometers across—from proteins important since life began to the latest creations of nanotechnology. Jointly funded by NIST and the National Science Foundation, the school’s organizers aim to inspire as much as enlighten.

“We want future scientists to see what these tools can do for their research, whatever field they happen to be in,” says the NCNR’s Dan Neumann, “and it works. More than 70 percent come back to do experiments at NIST, both before and after they earn their doctorates.”

The school alternates between two different courses: this year introduces students to inelastic scattering tools that reveal how very small objects move, and next year will concentrate on low angle scattering, which is useful for exploring the structure of larger objects from 1 to more than 1,000 nanometers wide. Neumann says the alternation helps students focus on their interests.

“We have lots of different instruments, and we want our students to experience what’s useful for their own research,” Neumann says. “They each get several hours of hands-on instruction on three instruments best suited to their research interest.”

Many of this year’s attendees, who are primarily budding engineers and materials scientists, say that the amalgam of inspiration and training on novel equipment has encouraged them to incorporate neutron scattering into their own future efforts. Adam Holferty, who studies chemical engineering at the University of Missouri, says he hopes to use his new knowledge this fall.

“I’m working on ways to deliver drugs by using nanoparticles that break open when you put a magnetic field on them,” he says. “I’m betting neutron beams will be useful in exploring the particles’ properties, and now I might be able to get in on some scattering experiments back at the MU’s research reactor. It’s one thing knowing theory, but knowing how to apply it in practice is a big help.”

Media Contact: Chad Boutin, boutin@nist.gov, 301-975-4261

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NIST Issues Human Milk and Blood Serum SRMs for Contaminant Measurements

Responding to scientists' need to measure organic contaminants in human body fluids, the National Institute of Standards and Technology (NIST) has recently made four new Standard Reference Materials (SRMs) available for purchase. Developed in collaboration with the Centers for Disease Control and Prevention (CDC), the human milk and serum SRMs have certified levels of contaminants, including flame retardants and pesticides, commonly found in the U.S. population. Scientists at the CDC and other laboratories will use the SRMs as controls in their experiments to ensure their methods are providing trustworthy results.

photo of SRM bottles

The new NIST Standard Reference Materials for organic contaminants in human body fluids reflect changes in contaminant levels since the last materials were issued in 2000—levels of PCBs, pesticides, dioxins/furans and other contaminants have decreased by 50 percent while the levels of brominated flame retardants have been on the rise.

Credit: NIST
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NIST first released its first serum-based SRM (SRM 1589 Polychlorinated Biphenyls in Human Serum) in 1985 to aid with the detection of polychlorinated biphenyls (PCBs), a toxic mixture of compounds used in transformer oils that was banned in the U.S. in the 1970s. Since NIST researchers last updated the SRM in 2000, the levels of PCBs, pesticides, dioxins/furans and other contaminants have decreased by 50 percent while the levels of brominated flame retardants, chemicals found in carpeting and upholstery, have been on the rise. NIST researchers created the new SRMs to reflect these changes.

The first of their kind, the milk SRMs contain similar contaminants as the serum materials.

To prepare these SRMs, scientists collected 200 liters of blood serum and 100 liters of milk from banks across the United States and divided the sample pools in half. (Note that the milk that was used to prepare the SRM was not suitable for feeding babies because the donors may have taken medications such as acetaminophen or the milk had reached its expiration date.) Researchers packaged half of each material as received, containing the natural (unfortified) level of contaminants, and treated (fortified) the other halves with a solution containing 172 selected contaminants. The fortified samples contain a concentration of those contaminants at levels five to 10 times higher than the median concentrations found in the U.S. population.

NIST SRMs have been rigorously tested and certified as having specific properties that researchers can trust as accurate within stated levels of uncertainty. The values stated on the certificates for these SRMs were measured by NIST and the CDC using a number of different methods including gas and liquid chromatography with mass spectrometry detection.

For more information, see:

 

Contact NIST Technology Services at (301) 975-2200.

Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735

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NIST Extends Deadline for 2009 Technology Innovation Program Competition

The National Institute of Standards and Technology (NIST) announced today that it is extending the deadline for submitting proposals to its Technology Innovation Program competition to 3 p.m. Eastern Time, Tuesday, July 7, 2009. The original deadline was on June 23, 2009, but technical difficulties at the Web site that accepted electronic submissions prevented some applications from being filed before the deadline.

During the extended time period, NIST will accept only paper submissions, which must be received by the new deadline. Proposals should be sent to the National Institute of Standards and Technology, 100 Bureau Drive, Stop 4750, Gaithersburg, MD 20899-4701.

The TIP competition, originally announced on March 26, 2009, offers multiyear, cost-shared research funding in two major areas of national interest, civil infrastructure and advanced materials in manufacturing. See “2009 Technology R&D Competition to Address Civil Infrastructure, Manufacturing.”

For more details on the 2009 TIP competition, see the competition Web page at www.nist.gov/tip/comp_09/comp09_home.html. A copy of the Federal Register notice announcing the deadline extension is available at www.nist.gov/tip/2009_tip_frn_extension_final.pdf. For more details, contact Thomas Wiggins at thomas.wiggins@nist.gov or by telephone (301) 975-5416.

Media Contact: Michael Baum, michael.baum@nist.gov, 301-975-2763

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NIST Seeks Comments on Smart Grid Report

The National Institute of Standards and Technology (NIST) is requesting public comment on a draft report* that identifies issues and proposes priorities for developing interoperability standards for a “smart” electric power grid.

In a Federal Register notice** published on June 30, NIST formally announced the availability the nearly 300-page report, prepared, under contract, by the Electric Power Research Institute (EPRI).*

Under the Energy Independence and Security Act (EISA) of 2007, NIST has “primary responsibility to coordinate development of a framework that includes protocols and model standards for information management to achieve interoperability of smart grid devices and systems …” NIST is working closely with the Department of Energy, the lead agency in the federal Smart Grid effort.

NIST will use the EPRI report in drafting the NIST Smart Grid Interoperability Standards Framework. The NIST document will describe a high-level architecture, identify an initial set of key standards, and provide a roadmap for developing new or revised standards needed to realize the Smart Grid. The first release of NIST-prepared framework is planned to be available in September.

Comments should reference the Federal Register notice and must be received on or before July 30, 2009. Written comments may be sent to: George Arnold, 100 Bureau Drive, Stop 8100, NIST, Gaithersburg, MD 20899-8100. Electronic comments may be sent to: smartgridcomments@nist.gov

* Report to NIST on the Smart Grid Interoperability Standards Roadmap (Contract No. SB1341-09-CN-0031—Deliverable 7) Prepared by the Electric Power Research Institute (EPRI), June 17, 2009. Available at: www.nist.gov/smartgrid/

** Request for Comments on “Report to NIST on the Smart Grid Interoperability Standards Roadmap” Federal Register, June 30, 2009, Volume 74, Number 124, p 31254, Docket Number: 0906181063-91064-01.

Media Contact: Mark Bello, mark.bello@nist.gov, 301-975-3776

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Baldrige Recipients to Share Strategies at Upcoming Regional Conferences

Senior leaders from the three organizations selected for the 2008 Malcolm Baldrige National Quality Award, as well as representatives from past Award recipients, will share their best practices and results at one-day regional conferences on Sept. 15, 2009, in Milwaukee, Wisc., and Oct. 2, 2009, in Cambridge, Mass. Participants can network with the recipients and gather valuable tips on applying the Baldrige Criteria for Performance Excellence.

The 2008 Baldrige Award recipients—listed with their category—are:

  • Cargill Corn Milling North America, Wayzata, Minn. (manufacturing)
  • Poudre Valley Health System, Fort Collins, Colo. (health care)
  • Iredell-Statesville Schools, Statesville, N.C. (education)


The Baldrige Program promotes excellence and innovation in organizational performance, recognizes the achievements and results of U.S. organizations, and publicizes successful performance strategies. The Award is not given for specific products or services. Since 1988, 75 organizations have received Baldrige Awards.

To register online for the conferences, go to www.maccinc.com/brc09/. A discounted advanced registration fee is available for the Milwaukee conference until Aug. 24, 2009 and for the Cambridge conference until Sept. 10, 2009.

For more information on the regional conferences, go to www.baldrige.nist.gov/2009_Regionals/Regionals.htm. You also may contact the Baldrige Program at (301) 975-2036 or baldrige@nist.gov.

The day after the Milwaukee conference, Sept. 16, 2009, Mercy Health System, a 2007 Baldrige Award recipient, will sponsor a Sharing Day. Details will be available soon on the regional conference Web page listed in the preceding paragraph.

The 2009 Regional Conferences are co-sponsored by MassExcellence, the Wisconsin Forward Award, the Alliance for Performance Excellence and the Foundation for the Malcolm Baldrige National Quality Award in conjunction with the National Institute of Standards and Technology (NIST).

Media Contact: Michael E. Newman, michael.newman@nist.gov, 301-975-3025

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Workshop to Aim for Security, Accessibility in Future Voting Systems

Creating voting machines that are both trustworthy and easy to use is the goal of the End-to-End Voting Systems Workshop, which should interest anyone concerned with ensuring that elections are run fairly, smoothly and with verifiable results.

The idea behind “end-to-end” systems is that voting machines generate proof that all votes cast in an election were properly counted, according to Andrew Regenscheid of the National Institute of Standards and Technology (NIST).

The workshop, organized by NIST, will be held Oct. 13 and 14 at George Washington University’s Cloyd Heck Marvin Center in Washington, D.C. According to Regenscheid, the gathering is intended to encourage future research in the field of voting system design—with an emphasis on making end-to-end voting systems accessible to voters and poll workers.

“Many end-to-end voting systems have been designed, but the few working prototypes are often difficult to use and understand,” says Regenscheid, who is part of the voting team within NIST’s Computer Security Division. “We expect many experts from the cryptography and computer security communities, but we’re trying to get usability and accessibility experts involved as well.”

Regenscheid added that end-to-end systems have been used in small-scale elections, and the city of Takoma Park, Md., is planning to use one such system in their 2009 municipal election.

Key issues concerning end-to-end systems, such as how security and usability will interact, will be discussed by presenters, who are invited to submit papers by Aug. 2, 2009 at e2e@nist.gov. Speakers will be selected by Aug. 30. Further information about the workshop can be found at www.csrc.nist.gov/groups/ST/e2evoting/index.html.

Media Contact: Chad Boutin, boutin@nist.gov, 301-975-4261

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Quicklinks

NIST YouTube Channel Features Ultraprecise Measurement with Lasers

screenshot of lidar videoThe latest addition to the growing selection of videos on the National Institute of Standards and Technology (NIST) YouTube Channel (www.youtube.com/usnistgov) is a look at the agency's new super-accurate method of measurement--using lasers to quickly pinpoint the absolute distance between multiple objects to within a few nanometers, even when the objects are tens of kilometers or more apart. Incorporating novel precision laser systems called frequency combs, NIST's LIDAR (light detection and ranging) system could prove to be useful in formation flying of satellites.

For more information on the LIDAR system, see “NIST’s LIDAR May Offer Peerless Precision in Remote Measurements,” (NIST Tech Beat, June 2, 2009).

Media Contact: Michael E. Newman, michael.newman@nist.gov, 301-957-3025

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NIST Physicist, Chemist Receive Federal Public Service Award

Physicist Sae Woo Nam and chemist Stephan Stranick of the National Institute of Standards and Technology (NIST) are among 12 federal employees who were presented with the Arthur S. Flemming Award in ceremonies held June 1, 2009, at George Washington University. Established in 1948, the Flemming Awards honor those with three to 15 years of public service for extraordinary contributions to the federal government.

Nam was recognized for his “pioneering contributions and leadership in the field of single photonics.” The award citation notes that Nam is “known worldwide for the invention and application of groundbreaking single photon detection systems, which are furthering some of the world’s most challenging endeavors, including quantum cryptography, quantum computing, the examination of fundamental assumptions of quantum mechanics, and the ultimate traceability of optical power.

Stranick received his award for “innovations in chemical imaging microscopy techniques below the diffraction limit of light.” Strancik’s citation notes that his “design and demonstration of novel near-field optical microscopy platforms have resulted in dramatic spatial resolution improvements in the visible, infrared and microwave wavelength regimes. His innovations led to marked increases in sensitivity and throughput, allowing for far greater applicability of spectroscopic techniques such as Raman to industrially relevant chemical systems.”

For more information see the Arthur S. Flemming Awards Web page at www.gwu.edu/~flemming/ .

Media Contact: Michael E. Newman, michael.newman@nist.gov, 301-975-3025

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