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Tech Beat - February 24, 2009

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Editor: Michael Baum
Date created: April 7, 2011
Date Modified: April 7, 2011 
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Probing and Controlling ‘Molecular Rattling’ May Mean Better Preservatives

For centuries, people have preserved fruit by mixing it with sugar, making thick jams that last for months without spoiling. Now scientists at the National Institute of Standards and Technology (NIST) have discovered* a fundamental property of mixture behavior that might help extend the life of many things including vaccines, food and library books—and save money while doing it.

illustration of preservatives

Preservatives like sugar surround and protect complex molecules (foreground), but varying degrees of movement within the preservative—symbolized by the different colors in the background—are a major contributor to spoilage. Recent NIST findings concerning the fundamental behavior of mixtures (such as the combination above) could dramatically extend the shelf lives of vaccines and other biological materials.

Credit: NIST
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In addition to jams, sugars are often used to preserve pharmaceuticals and similar biological materials. There are a number of mechanisms involved, but recently the local stiffening of the preservative was identified as a factor that can increase shelf life. Basically, stiffening the preservative decreases the ‘rattling’ of the fluid’s molecules and stabilizes the product, presumably because these rattling motions are intimately involved in spoiling—for instance, in the protein degradation processes that lead to the loss of biological function. Several years ago, the NIST team discovered the practical importance of high-frequency molecular rattling for protein preservation.**

But while sugars and other preservatives such as salts have been used since ancient times, the prediction of how well a preservative works for a specific material has remained more an art than a science. Now, however, the NIST team has developed a relatively accessible measurement method for precisely quantifying the slowing down (or enhancement) of the local rattling motions in preservative formulations and have introduced a general mathematical framework for describing these changes. “This should remove much of the guesswork in determining the best way to protect a particular commodity,” says Jack Douglas of Polymers Division of NIST.

In the new paper, the team reveals a general pattern of behavior in the change in the rattling motions in mixtures that appears to apply to a variety of materials; these findings promise to be very helpful in the future development of preservatives. The paper also focuses on understanding the fundamental origin of high-frequency rattling’s effects, and it addresses enhancements in measurement and analysis that should allow researchers to optimize the preservation process.

“There’s a real regularity with which these changes occur, and we found a simple mathematical model that encapsulates these changes,” Douglas says. “The value here is that this mathematical framework allows you to consider this problem for many different materials.”

Douglas speculates that the discovery could help to extend the shelf life of vaccines significantly and also could be applied to preserving other biological materials such as seeds and prepared foods. The insight gained could even help to preserve library books. “These measurements can help determine the rate at which the changes occur, and that would help you predict how using more or less preservative might affect things, or how one substance stacks up against another,” Douglas says. “It could hasten discovery of the optimal additive for achieving a given end.”

* T. Psurek, C.L. Soles, K.A. Page, M.T. Cicerone and J.F. Douglas. Quantifying changes in the high-frequency dynamics of mixtures by dielectric spectroscopy. Journal of Physical Chemistry B, 2008, 112, 15980-15990.

** M.T. Cicerone and C.L. Soles. Fast dynamics and stabilization of proteins: Binary glasses of trehalose and glycerol. Biophysical Journal 2004, 86, 3836-3845.

Edited on Feb. 25, 2009 to correct figure caption.

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

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Cross-Dressing Rubidium May Reveal Clues for Exotic Computing

Neutral atoms—having no net electric charge—usually don’t act very dramatically around a magnetic field. But by “dressing them up” with light, researchers at the Joint Quantum Institute (JQI), a collaborative venture of the National Institute of Standards and Technology (NIST) and the University of Maryland at College Park, have caused ultracold rubidium atoms to undergo a startling transformation. They force neutral atoms to act like pointlike charged particles that can undergo merry-go-round-like “cyclotron” motions just as electrons do when subjected to a suitable magnetic field. This extreme makeover for ultracold atoms promises to give physicists clues on how to achieve an exotic form of computation that would rely upon special “fractionally charged” particles dancing around on a surface.

Just as good theatrical plays provide teachable insights about complex human situations, ultracold atomic gases are ideal proxies for studying complex phenomena in physics. Since it is relatively easy to manipulate the energy levels of ultracold atoms in gases and to control the interactions between them, scientists can learn important clues about physical phenomena that occur in more complicated and less controllable liquid or solid systems.

Among such complex phenomena are the quantum Hall and fractional quantum Hall effects, the subjects of the 1985 and 1998 Nobel Prizes in physics. In the latter effect, low-temperature electrons, confined to a plane and placed in high magnetic fields, can act as if they form “quasiparticles” carrying a fraction of an electric charge as well as several bundles of magnetism known as “magnetic flux quanta.” Physicists believe an as-yet-unseen configuration of such quasiparticles might provide a practical system for achieving “topological quantum computing,” in which quasiparticles on a two-dimensional surface would be able to perform powerful logic operations that obey the particular rules of quantum mechanics.

With this goal in mind, postdoc Yu-Ju Lin, physicist Ian Spielman and the rest of the JQI team have set out to make a gas of neutral atoms behave like electrically charged particles. They couldn’t simply add electric charges to the atoms, or play around with electrons themselves because their mutual electrical repulsion would cause the cloud to fly apart.

In their experiment, they cause a gas of rubidium-87 to form an ultracold state of matter known as a Bose-Einstein condensate. Then, laser light from two opposite directions bathes or “dresses” the rubidium atoms in the gas. The laser light interacts with the atoms, shifting their energy levels in a peculiar momentum-dependent manner. One nifty consequence of this is that the atoms now react to a magnetic field gradient in a way mathematically identical to the reaction of charged particles like electrons to a uniform magnetic field. “We can make our neutral atoms have the same equations of motion as charged particles do in a magnetic field,” says Spielman.

In this first experiment, Spielman and colleagues have effectively “put an electric charge” on atoms, but haven’t “turned on the field.” In subsequent experiments, they plan to introduce an effective magnetic field and watch “electrified” rubidium atoms go on their merry cyclotron ways, with the goal of revealing new insights about the fractional quantum Hall effect and topological computing. Stay tuned!

* Y.-J. Lin, R.L. Compton, A.R. Perry, W.D. Phillips, J.V. Porto and I.B. Spielman, A Bose-Einstein condensate in a uniform light-induced vector potential. Physical Review Letters (forthcoming).

Media Contact: Ben Stein, ben.stein@nist.gov, 301-975-3097

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Nanotechnologists Gain Powerful New Materials Probe

photo of MACS

Top view of the MACS multiaxis detector system (seen before being enclosed in shielding material). With more neutrons striking the sample and more detectors surrounding it, MACS will greatly extend the capabilities of neutron inelastic scattering as a materials probe technique in nanotechnology and basic science. Principal investigator Collin Broholm of the Johns Hopkins University is seen examining the alignment of one of the 20 detection channels.

Copyright: Robert Rathe
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Researchers at the National Institute of Standards and Technology (NIST) and The Johns Hopkins University have constructed a unique tool for exploring the properties of promising new materials with unprecedented sensitivity and speed—potentially allowing them to identify quickly those most useful for nanotechnology and industrial applications.

This novel instrument, called the Multi-Axis Crystal Spectrometer (MACS), is a variation on several other spectrometers at the NIST Center for Neutron Research (NCNR), where MACS is located. Like them, MACS bombards a sample of material with low-energy neutrons, which then bounce off the sample’s constituent atoms in specific directions and with specific velocities that reflect the arrangement of atoms within the material. Analyzing how neutrons scatter from a sample can tell scientists a great deal about the material’s physical properties, but older spectrometers are limited to relatively large samples and offer less range in the conditions under which they can be tested.

“These limitations are problematic in nanotechnology,” says Professor Collin Broholm of the Johns Hopkins University, “because oftentimes you grow a new material as a tiny crystal weighing only four or five milligrams, and then you want to see how it behaves under, say, an intense magnetic field.”

Not only can MACS overcome these limitations, but its unique construction allow has additional advantages. Many spectrometers provide just a single “channel” for detection, whereas MACS offers 20, forming a semicircle behind the sample—an arrangement that leads Broholm to compare MACS to a wide-angle, high-resolution lens. These improvements mean that MACS could become a favorite tool for scientists who must choose—and choose quickly—what material to grow next.

“With previous instruments for inelastic scattering from magnetic materials, 80 milligrams is about the smallest sample you can work with,” Broholm says. “But with MACS, we might be able to get detailed information about magnetic interactions even from a nano-structured thin film sample. These are the sort of interactions that nanotechnologists are trying to take advantage of when they design and shape things at the nanoscale.”

Broholm’s team is still fine-tuning MACS and expects to issue a full call for proposals to use the new spectrometer in about six months. Additional information on the NIST Center for Neutron Research http://www.ncnr.nist.gov/, a national user facility, is available on the facility’s Web site, including a list of available instruments at http://www.ncnr.nist.gov/instruments/. MACS is supported by the National Science Foundation.

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

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Updated Recommendations for Protecting Wireless, Remote Access Data

Telecommuting has freed many to work far from the confines of the office via laptop, but the price of working while sipping a latte at that sunny café is the danger that a public network will not keep the data that passes through it safe. Now, to combat the risk inherent in remote access, the National Institute of Standards and Technology (NIST) has updated its guide on maintaining data security while teleworking.

The revised guide offers advice for protecting the wide variety of private and mobile devices from threats that have appeared since the first edition appeared in August 2002. Together with the preponderance of dangerous malware on the Web, the vulnerability of wireless transmissions from mobile devices has created dramatic new security challenges.

“In terms of remote access security, everything has changed in the last few years. Many Web sites plant malware and spyware onto computers, and most networks used for remote access contain threats but aren’t secured against them,” says Karen Scarfone of NIST’s Computer Security Division. “However, even if teleworkers are using unsecured networks, the guide shows the steps organizations can take to protect their data.”

Among these steps is the recommendation that an organization’s remote access servers—the computers that allow outside hosts to gain access to internal data—be located and configured in ways that protect the organization. Another is to ensure that all mobile and home-based devices used for telework be configured with security measures so that exchanged data will maintain its confidentiality and integrity. Above all, Scarfone says, an organization’s policy should be to expect trouble and plan for it.

“You should assume external environments contain hostile threats,” she says. “This is a real philosophy shift from several years ago, when the attitude was essentially that you could trust the home networks and public networks used for telework.”

The new guide provides recommendations for organizations. A companion publication* offers advice for individual users on securing their own mobile devices.

While intended primarily for U.S. federal government agencies, the guide has been written in broad language in order to be helpful to any group that engages in telework. Formally titled Special Publication 800-46 Revision 1, Guide to Enterprise Telework and Remote Access Security, it is available at the NIST Computer Security Resource Center’s draft publication Web site: http://csrc.nist.gov/publications/PubsDrafts.html.

* SP 800-114, User’s Guide to Securing External Devices for Telework and Remote Access, http://csrc.nist.gov/publications/nistpubs/800-114/SP800-114.pdf.

Edited on Feb. 25, 2009 to insert proper document links.

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

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NIST and French Lab to Study Weathering of Advanced Composites for Bridges and Piers

SPHERE researchers

Weather SPHERE: Researchers from France's National Scientific and Technological Institute and NIST will work together to learn more about the effect of weathering on fiber-reinforced polymer composites that may be used in bridges and piers. NIST's SPHERE (Simulated Photodegradation via High Energy Radiant Emission) accelerates outdoor weathering of test materials.

Credit: NIST
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The National Institute of Standards and Technology (NIST) has signed an agreement to collaborate with the French Laboratoire Central des Ponts et Chaussées (National Scientific and Technological Institute, LCPC) to investigate further the implementation of fiber-reinforced polymer (FRP) composites in civil infrastructure. These FRP composites are of mutual interest to both countries because they could be used for high-strength applications such as wind turbines or bridges and piers.

This statement of intent to collaborate is one of the first to be signed under the auspices of the “Agreement on Science and Technology Cooperation Between The Government of the United States of America and The Government of The French Republic,” signed on Oct. 22, 2008. The partners will share facilities and research, exchange information on related research topics and researchers, and publish joint scientific and technical reports.

The first planned project is to test the long-term weathering effects on advanced composite materials using NIST’s SPHERE (Simulated Photodegradation via High Energy Radiant Emission), a source of high-intensity ultraviolet rays that accelerates outdoor weathering of polymeric materials and composites. The SPHERE provides data on long-term exposure to ultraviolet radiation, temperature and relative humidity, which enables researchers to better predict a material’s service life. For more details on the LCPC research program, see the laboratory Web site at www.lcpc.fr/en/home.dml.

Media Contact: Evelyn Brown, evelyn.brown@nist.gov, 301-975-5661

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Researchers Demonstrate Novel ‘Quantum Data Buffering’ Scheme

In a new demonstration of physicists’ growing ability to control the “spooky” quantum dynamics phenomenon called entanglement, researchers from the National Institute of Standards and Technology (NIST) and the University of Maryland (UM) have announced* that they can cache sizable amounts information in a “quantum buffer” without disturbing the fragile entanglement of quantum states at the heart of the strange world of quantum computing. Such a buffer could be used to control the data flow inside a yet-to-be-built quantum computer that theoretically could solve problems unreachable by the best conventional computers.

diagram of a setup for a quantum buffer

In this simplified representation of the experimental setup for a “quantum buffer,” a cell containing rubidium gas is used to produce a pair of information-rich entangled images. One of the images goes through a second rubidium gas cell and slows down, which is potentially useful for feeding data at properly timed intervals to future quantum computers. The delay can be controlled such that, during the time it takes one image to travel a centimeter, the other image can travel up to 8 meters. The twisted loops illustrate the entanglement between the images.

Credit: A. Marino/JQI
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“If you want to set up some sort of communications system or a quantum information-processing system, you need to control the arrival time of one data stream relative to other data streams coming in,” says Alberto Marino of the NIST/UM Joint Quantum Institute (JQI), lead author of the paper. “We can accomplish the delay in a compact setup, and we can rapidly change the delay if we want, something that would not be possible with usual laboratory apparatus such as beamsplitters and mirrors.”

This new work follows up on the researchers’ landmark creation in 2008 of pairs of multi-pixel quantum images (see “Physicists Produce Quantum-Entangled Images.”) In the JQI work, each quantum image is carried by a light beam and consists of up to 100 “pixels.” A pixel in one quantum image displays random and unpredictable changes say, in intensity, yet the corresponding pixel in the other image exhibits identical intensity fluctuations at the same time, and these fluctuations are independent from fluctuations in other pixels. This entanglement can persist even if the two images are physically disconnected from one another.

By using a gas cell to slow down one of the light beams to 500 times slower than the speed of light, the group has demonstrated that they could delay the arrival time of one of the entangled images at a detector by up to 27 nanoseconds. The correlations between the two entangled images still occur—but they are out of sync. A flicker in the first image would have a corresponding flicker in the slowed-down image up to 27 nanoseconds later.

While such “delayed entanglement” has been demonstrated before for individual photons, it has never been accomplished in information-rich quantum images. “What gives our system the potential to store lots of data is the combination of having multiple-pixel images and the possibility of each pixel containing ’continuous’ values for properties such as the intensity,” says co-author Raphael Pooser.

For more information, see “NIST/Maryland Researchers Demonstrate ’Quantum Data Buffering’ Scheme.”

* A.M. Marino, R.C. Pooser, V. Boyer and P.D. Lett. Tunable delay of Einstein-Podolsky-Rosen entanglement. Nature. Feb. 12, 2009.

Media Contact: Ben Stein, ben.stein@nist.gov, 301-975-3097

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Quicklinks

NanoFab Adds New Capbilities

The NanoFab (nanoscale fabrication facility) at the National Institute of Standards and Technology (NIST) is expanding its capabilities to serve researchers, academic institutions and businesses that specialize in developing and bringing to market nanotechnology-related products and processes. Managed by NIST’s Center for Nanoscale Science and Technology (CNST), the national user facility is placing a second high-voltage large-field electron-beam lithography system into operation in April, and also has added several other new state-of-the-art instruments for fabricating nanoscale devices and making measurements. The center recently added a Heidelberg DWL-66FS laser pattern generator for maskless lithography, an Oxford FlexALRPT for atomic layer deposition, and two new ICP reactive ion etch systems.

The CNST’s mission is to increase U.S. innovation and competitiveness in nanoscale measurement and fabrication. Its NanoFab now houses more than 50 specialized instruments that are available for use by outside organizations. For more information on the NanoFab, call (301) 975-4529 or visit the NanoFab Web pages at http://cnst.nist.gov/nanofab/nanofab.html.

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

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ComSci Fellowship Program Accepting Applications for 2009-2010

Senior federal employees who want a broader perspective on the development of the nation’s science and technology policy are invited to apply for the Commerce Science and Technology Fellowship (ComSci) Program. The ComSci program affords federal employees an opportunity to study the national and international issues that drive the development, application and management of policies that concern the nation’s science and technology research effort. Applications for the 2009-2010 class, which begins in September, are due April 8.

The competitive program, created in 1964, is open to senior level (GS-13 and above) executive branch employees, including military service members. Twenty fellowships will be awarded for the 10-month program. Through a varied schedule of activities and intensive work assignments in a federal agency or on Capitol Hill, fellows are exposed to the inner workings of the U.S. scientific establishment while simultaneously extending their professional network.

“This is the only in-depth program exclusively for federal employees that focuses on science and technology policy and leadership,” says NIST’s Marie Marques Bravo, director of the ComSci Program. “It’s also rare in that it’s government-wide. Participants get to meet people from many other agencies. There’s lots of cross-fertilization.”

Options for both full-time and part-time participation are available. Full-time participants receive a 10-month intensive and challenging work assignment in the government that is designed to provide policy-making and program management experience. Part-time participants continue working at their home agencies but commute on a weekly basis to participate in the ComSci Program seminars and site visits.

Applications are being accepted through April 8 at www.usajobs.gov, vacancy announcement ComSci-2009-0001. For more information, visit www.comsci.gov.

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

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New Report Summarizes Federal Tech Transfer Activities

Collaborative research agreements, invention licenses and several other technology transfer activities of the federal government trended upward between 2002 and 2007, according to a new, NIST-prepared summary report to the President and Congress. Over the five-year span, the number of active licenses of inventions and other intellectual property generated by research programs in the 11 agencies with internal research programs rose to 10,347, an increase of about 60 percent. Federal revenues from these licenses totaled nearly $150 million in fiscal year 2007, a jump of 54 percent. However, disclosures of new inventions and patenting activity dipped slightly over the same period. In contrast, the number of active cooperative research and development agreements, or CRADAs, increased 30 percent, to more than 7,300. This is the first year that NIST prepared the annual report on federal technology transfer activities. Previous editions were issued by the Commerce Department’s former Technology Administration. Current and past reports are available on the Web site of the NIST Office of Technology Partnerships at http://patapsco.nist.gov/ts/220/external/index.htm.

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

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Colorado Governor Ritter Honors NIST Internet Time Service

On Feb. 17, Governor Bill Ritter of Colorado presented the 2009 CO-LABS Governor’s Awards for Research Impact to scientists from five federal research laboratories, including the National Institute of Standards and Technology (NIST). In a ceremony at the governor’s mansion in Denver, the award in information technology was presented to physicist Judah Levine for his development of the NIST Internet Time Service, which allows users to synchronize computer clocks via the Internet.

Levine is a Fellow of NIST and a Fellow of JILA, a joint institute of NIST and the University of Colorado at Boulder. Since he spearheaded the development of the first automated computer time service in 1988, Levine has participated in the transformation of global timekeeping. Working with other scientists at NIST, he invented services that offer the precision of atomic-clock-based time to the public and to such high-tech systems as the nation’s electric power grid and telecommunications networks. NIST Internet Time Service now provides the exact time in response to more than 3 billion inquiries each day from clients such as the stock market and other financial institutions that rely on electronic transactions.* Time stamping of financial transactions is particularly important because some stock markets now require that time stamps be traceable to NIST. In addition, millions of people use NIST radio broadcasts to synchronize wall clocks, clock radios and wristwatches with atomic time.

Levine has worked at NIST since 1969 and previously has received several awards from NIST and the Department of Commerce.

CO-LABS is a nonprofit organization that educates about and advocates for Colorado’s 24 federal research labs. For more on the awards, see the governor’s office news release “Gov. Ritter Honors Colorado’s Federal Research Labs.”

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

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