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Tech Beat - May 20, 2014

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Editor: Michael Baum
Date created: May 20, 2014
Date Modified: May 20, 2014 
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JILA Study Finds Crowding Has Big Effects on Biomolecules

Crowding has notoriously negative effects at large size scales, blamed for everything from human disease and depression to community resource shortages. But relatively little is known about the influence of crowding at the cellular level. A new JILA study shows that a crowded environment has dramatic effects on individual biomolecules.

RNA molecule
Artist's conception of an RNA molecule (large purplish ladder) in the process of folding as it is crowded by a common polymer, polyethylene glycol (turquoise strands). RNA folds more frequently--that is, the branch on the left folds upward--when it is crowded.
Credit: Baxley/JILA and Talbott/NIST
high resolution image

In the first data on the underlying dynamics (or kinetics)of crowded single biomolecules , reported in Proceedings of the National Academy of Sciences,* JILA researchers found that crowding leads to a 35-fold increase in the folding rate of RNA (ribonucleic acid), while the unfolding rate remains relatively stable.

RNA is a long chain-like molecule that contains genetic information, makes proteins and catalyzes biological reactions. It must fold into the correct 3D shape to function properly. The new results show that while RNA usually spends most of its time unfolded, in a crowded situation it folds much more often, although it remains folded for the usual period of time during each round.

"Cells are 25 to 35 percent filled with 'stuff'—proteins, nucleic acids, lipids, etc.—and the effect of crowding on simple reactions like folding of nucleic acids and proteins is not well understood," JILA/NIST Fellow David Nesbitt says. "Almost all detailed kinetic data comes from in vitro studies, that is, not in a living cell.

"But our work at the single-molecule level suggests that the rates and equilibrium constants (where folding and unfolding rates are equal) for simple nucleic acid folding processes may be shifted by up to 400,000 percent or more from what one might expect from such uncrowded solution studies."

Nesbitt's group used a specialized microscope to study RNA folding over time in solutions containing various concentrations of a large common polymer, PEG.** The size of the PEG molecule constrains the 3D space around the RNA, mimicking the contents of crowded cells better than the typical dilute solutions used in test-tube studies.

Although PEG was previously known to encourage the compactor folded states of biomolecules, the JILA results are the first to determine the underlying processes. The results were not obvious, in that crowding might seem likely to suppress RNA unfolding. JILA researchers suggest that instead, the opposite process is at work: Crowding lowers the energy required for RNA to achieve the transition state for folding, making it easier to fold.

The JILA study also analyzed temperature-related data to show that the boost in the RNA folding rate constant is largely due to the disorder (or entropy) of the mixture, rather than simply the tendency for RNA to stabilize in the shape with the lowest energy.

In addition to collecting experimental data, JILA researchers used a simple particle model to estimate what would happen in the extremely crowded environment of the cell. The results suggest that the RNA folding equilibrium constant could potentially increase more than 4,000-fold—resulting in a dramatically different biochemical composition—while the folding rate could increase more than 1,000-fold. JILA researchers speculate that such extreme effects could profoundly influence both the rates and preferred directions of complex biochemical pathways in cells. Further studies are needed to determine whether the model can be extended to other cell contents and other RNA structures.

The research was funded by the National Science Foundation and NIST.

*N.F. Dupuis, E.D. Holmstrom and D.J. Nesbitt. Molecular crowding effects on single molecule RNA folding/unfolding thermodynamics and kinetics. Proceedings of the National Academy of Sciences. Published online in Early Edition, May 21, 2014. doi:10.1073/pnas.1316039111
**Specifically, hmwPEG: high molecular weight polyethyleneglycol.

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

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From Separation to Transformation: Metal-Organic Framework Shows New Talent

This gift from science just keeps on giving. Measurements taken at the National Institute of Standards and Technology (NIST) show why a material already known to be good at separating components of natural gas also can do something trickier: help convert one chemical to another, a process called catalysis. The discovery is a rare example of a laboratory-made material easily performing a task that biology usually requires a complex series of steps to accomplish.

ethanol framework
This iron-based metal-organic framework (large structure) can catalyze a reaction that transforms ethane (gray and light blue molecules) into pure ethanol (light blue, red and gray). Scientists think the framework could help reveal ways to mimic other biological functions.
Credit: NIST
high resolution image

The material is a metal-organic framework (MOF), one of a class of substances whose porosity, high surface area and tunable properties make them promising for applications such as gas storage and drug delivery. This particular iron-based MOF, which the research team refers to as Fe-MOF-74,was built in the lab of Jeffrey Long, a professor of chemistry at the University of California Berkeley, who also has patented it.*

Having learned two years ago** that Fe-MOF-74 could effectively separate closely related components of natural gas from one another, this time Long's collaborators at the NIST Center for Neutron Research (NCNR) looked at its power to catalyze reactions—that is, accelerate or enable the chemical reaction of two other materials. In this case, they turned ethane,a component of natural gas, into ethanol, a component of vodka. The research team knew that the iron in the MOF could change from possessing one number of electrons to another, which raised interesting questions.

"One of the big long-term goals of biochemistry is to build things with specific functions from the ground up," says the NCNR's Craig Brown. "It's hard to simply make things like nature does, because she often converts one material into another in a fiendishly complex way. But with a MOF that can mimic nature's effect, we might be able to make the same thing, but right in the lab and far more easily."

While the MOF was great at catalyzing the reaction, the team wasn't sure why. The search for understanding led to two (fairly technical)discoveries at the NCNR: the importance of the MOF's iron for catalysis, and the reason the oxidizer worked so well.

Iron being able to change its number of electrons is the key to creating a high-yield catalytic process. When the team substituted magnesium for 10 percent of the iron in the MOF, the reaction produced 40 percent less ethanol than before. The NCNR's neutron diffractometer helped clarify why, and they also showed that the oxidizer—nitrous oxide, a lopsided molecule with oxygen at one end and two nitrogen atoms at the other—must connect its oxygen end to the iron in the MOF for catalysis to occur.

Brown says exploring the catalytic behavior in this material may reveal other ways to use MOFs to mimic what biology can do. "We hope to get more insights into the reactivity of this material and possibly the design, synthesis and catalytic activities of other MOFs," he says.

*D.J. Xiao, E.D. Bloch, J.A. Mason, W.L. Queen, M.R. Hudson, N. Planas, J. Borycz, A.L. Dzubak, P. Verma, K. Lee, F. Bonino, V. Crocellá, J. Yano, S. Bordiga, D.G. Truhlar, L. Gagliardi, C.M. Brown, J.R. Long. Oxidation of ethane to ethanol by N2O in a metal–organic framework with coordinatively unsaturated iron(II) sites. Nature Chemistry, DOI 10.1038/nchem.1956,May 18, 2014.
**See the April 2012 NIST Tech Beat story, "Novel Filter Material Could Cut Natural Gas Refining Costs" at www.nist.gov/public_affairs/tech-beat/tb20120403.cfm#filter.

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

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Don't Blink! NIST Studies Why Quantum Dots Suffer from 'Fluorescence Intermittency'

Researchers at the National Institute of Standards and Technology (NIST), working in collaboration with the Naval Research Laboratory, have found that a particular species of quantum dots that weren't commonly thought to blink, do.

14CNST002_Blinking_Quantum_Dot_Figure_LR
Experimental apparatus used to investigate quantum dot blinking. A quantum dot is optically excited using a laser and its fluorescence is collected and split into two paths, each equipped with a single photon avalanche diode (SPAD). A time correlator is used to record the arrival times of the photons on each SPAD, from which the photon autocorrelation function is determined. SEM images of the quantum dot devices studied include a circular grating 'bullseye' optical cavity (b) and a microdisk optical cavity (c).
Credit: NIST
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So what? Well, although the blinks are short—on the order of nanoseconds to milliseconds—even brief fluctuations can result in efficiency losses that could cause trouble for using quantum dots to generate photons that move information around inside a quantum computer or between nodes of a future high-security internet based on quantum telecommunications.

Beyond demonstrating that the dots are blinking, the team also suggests a possible culprit.*

Scientists have regarded indium arsenide and gallium arsenide (InAs/GaAs) quantum dots to be promising as single photon sources foruse in different future computing and communication systems based on quantum technologies. Compared to other systems, researchers have preferred these quantum dots because they appeared to not blink and because they can be fabricated directly into the types of semiconductor optoelectronics that have been developing over the past few decades.

The NIST research team also thought these quantum dots were emitting steady light perfectly, until they came upon one that was obviously blinking (or was "fluorescently intermittent," in technical terms). They decided to see if they could find others that were blinking in a less obvious way.

While most previous experiments surveyed the dots in bulk, the team tested these dots as they would be used in an actual device. Using an extremely sensitive photon autocorrelation technique to uncover subtle signatures of blinking, they found that the dots blink over timescales rangingfrom tens of nanoseconds to hundreds of milliseconds. Their results suggest that building photonic structures around the quantum dots—something you'd have to do to make many applications viable—may make them significantly less stable as a light source.

"Most of the previous experimental studies of blinking inInAs/GaAs quantum dots looked at their behavior after the dots have been grown but before the surrounding devices have been fabricated," says Kartik Srinivasan, one of the authors of the study. "However, there is no guarantee that a quantum dot will remain non-blinking after the nanofabrication of a surrounding structure, which introduces surfaces and potential defects within 100 nanometers of the quantum dot. We estimate the radiative efficiency of the quantum dots to be between about 50 and 80 percent after the photonic structures are fabricated, significantly less than the 100 percent efficiency that future applications will require."

According to Marcelo Davanço, another author of the study, future work will focus on measuring dots both before and after device fabrication to better assess whether the fabrication is indeed a source of the defects thought to cause the blinking. Ultimately, the authors hope to understand what types of device geometries will avoid blinking while still efficiently funneling the emitted photons into a useful transmission channel, such as an optical fiber.

The NIST Center for Nanoscale Science and Technology (CNST) is a national nanotechnology user facility that enables innovation by providing rapid access to the tools needed to make and measure nanostructures. Researchers interested in accessing the techniques described here or in collaborating on their future development should contact Kartik Srinivasan.

*M. Davanço, C. Stephen Hellberg, S. Ates, A. Badolato and K. Srinivasan. Multiple time scale blinking in InAs quantum dot single-photon sources. Phys. Rev. B 89, 161303(R) – Published 16 April 2014.

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

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Spartanburg, S.C., Fire Experiments Will Test New Firefighting Tactics

Spartanburg fire test setup
NIST engineer works with a member of the South Carolina Fire Training Academy staff to conduct a pressure test on one of the instrumented structures that will be burned in tests of fire-fighting tactics later this week.
Credit: Madrzykowski/NIST
high resolution image

Fire researchers at the National Institute of Standards and Technology (NIST) will return to Spartanburg, S.C., on May 15-21, 2014, as part of a collaborative effort on a series of controlled-burn experiments in detached single-family homes slated for demolition.

Measurements of temperature, total heat flux and other ground truth data gathered during the live fire experiments will help the NIST team and its partners to further assess the effectiveness of new fire-suppression tactics known as transitional fire attack. Likened to the military concept of "softening the target," a transitional fire attack begins by applying water as soon as possible from the exterior of a burning house—before firefighters enter the structure—and then proceeds into the interior.

In contrast, the conventional "offensive attack" begins inside, requiring entry into the burning structure before any water is directed onto the fire.

NIST is collaborating with the International Society of Fire Service Instructors (ISFSI), the State of South Carolina Fire Training Academy and City of Spartanburg Fire Department. NIST helped to design the fire experiments and will provide measurement instruments and other equipment for recording conditions in the burning houses. The fires also will be recorded with videos and thermal imagers.

This is the second year that NIST will be collaborating with ISFSI and the South Carolina team.* ISFSI already has incorporated results and lessons learned from last year's experiments into its training programs for firefighters across the country.

The experiments will again be conducted in abandoned wood-frame, single-family houses near the site of an old textile mill, an area that is the site of a neighborhood redevelopment program.

The research project is supported by the Federal Emergency Management Agency's Assistance to Firefighters Grant Program. To learn more about NIST's firefighting technology research program, go to www.nist.gov/el/fire_research/firetech/index.cfm.

*See the January, 2013, NIST Tech Beat story, "'Live Burns' in Spartanburg, S.C., Will Benefit Research and Firefighter Training"at www.nist.gov/public_affairs/tech-beat/tb20130124.cfm#fire.

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

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World Metrology Day 2014: Measurements and the Global Energy Challenge

Take a tour of NIST's Net Zero Energy House in this video, "Nothing Lost is Everyone's Gain."

Credit: NIST

The theme of this year's World Metrology Day, "Measurements and the Global Energy Challenge," speaks to one of the defining issues of our time. One that is as far-reaching as any challenge we have ever faced. Keeping pace with our ever-growing energy needs while protecting our environment will require a host of new technologies, and those technologies depend on a robust system of measurement and calibration if they are to be built and used economically and maintained in good working order.

With more than 100 projects covering nearly every aspect of energy from generation (by conventional and alternative means) to transmission, metering, conservation and sustainability, the National Institute of Standards and Technology (NIST) is doing all it can to help solve the energy challenge.

Standards for the Smart Grid, energy-efficient lighting, photovoltaics, net-zero-energy buildings, and software for "smart" building are but a few of the many areas where NIST measurement research is having an impact.

For instance, the Nisters, the virtual family inhabiting NIST's Net-Zero Energy Residential Test Facility (NZERTF), earned about $40 by exporting 328 kilowatt hours of electricity to the local grid while meeting all of their varied energy needs during their first six months of occupancy.

NIST researchers' survival-of-the-fittest computer simulation uncovered a more efficient design for rooftop air-conditioning systems. The 3 percent improvement could be enough for a manufacturer to achieve compliance with increasingly stringent energy efficiency standards. The efficiency increase could also translate into material savings—a reduction in the amount of costly copper tubing in a heat exchanger without sacrificing performance.

A NIST spectroscopy innovation could improve the detection of greenhouse gases in the atmosphere. The high speed of the technique allows for very accurate measurements of atmospheric gases at rates that are faster than atmospheric changes in temperature and pressure due to turbulence and could potentially be used on a vehicle, aircraft or satellite.

And NIST will continue to work to address the pressing measurement and calibration needs of today while anticipating the needs of tomorrow.

World Metrology Day celebrates the signing of the Treaty of the Meter on May 20, 1875. By signing the treaty, representatives from 17nations, including the United States, recognized the importance of worldwide uniformity of measurements and established a collaborative global framework for the advancement of measurement science.

Each year, World Metrology Day is organized and celebrated jointly by the International Bureau of Weights and Measures (BIPM), which serves as the hub of national metrology institutes such as the National Institute of Standards and Technology (NIST), and the International Organization of Legal Metrology (OIML), an intergovernmental treaty organization that promotes harmony in legal metrology.

From all of us at NIST, have a great World Metrology Day!

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

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Capillary Device Significantly Improves Manufacture of Quality Liposomes

When the English author Sir Francis Bacon wrote "The world's a bubble" in 1629, it's a safe bet he wasn't thinking about microfluidics. However, for a research team led by scientists at the National Institute of Standards and Technology (NIST), Bacon's words could not be truer. Since 2004, their world has revolved around the development of increasingly sophisticated microfluidic devices to produce liquid-filled "bubbles" called liposomes for potential use as vehicles to deliver drugs directly to cancers and other diseased cells within the body.

3D Liposome Formation Device
Schematic of the NIST/University of Maryland 3D-microfluidic hydrodynamic focusing device for manufacturing vesicles known as liposomes. Phospholipids dissolved in alcohol flowing through the center capillary (red) mix with a water-based buffer solution added through the six surrounding tubes. Liposomes are created downstream from the convergence point.
Credit: NIST
high resolution image

Liposomes are spheres made of a double layer of phospholipids, the fat complexes that are the building blocks for animal cell membranes. They resemble simple cells with the "guts" removed. Widespread application of manufactured liposomes as artificial drug carriers has been hindered by a number of limiting factors such as inconsistency in size, structural instability and high production costs.

In a new article in the journal Lab on a Chip,* the team from NIST and the University of Maryland (UM) describes a new approach for overcoming these obstacles. The group's novel system is made up of bundled capillary tubes, costs less than a $1 to make and requires no special fabrication technology or expertise, yet consistently yields large quantities of uniform and sturdy vesicles.

Previous NIST/UM microfluidic liposome-generating devices were two-dimensional designs incorporating tiny channels etched into a silicon wafer with the same techniques used for making integrated circuits. Phospholipid molecules dissolved in isopropyl alcohol were fed via a central inlet channel into a "mixer" channel and focused into a fluid jet by a water-based solution added through two side channels. The components blended together as they mixed at the interfaces of the flowing fluid streams, directing the phospholipid molecules to self-assemble into nanoscale vesicles of controlled size.

In the latest NIST/UM advance, the planar structure has been replaced by a three-dimensional microfluidic device. The new liposome generator consists of a 3-millimeter-diameter glass cylinder containing a bundle of seven tiny glass capillary tubes—each a millimeter across, or about the diameter of a pinhead—with one in the center and six surrounding it. A micro-sized plastic capillary (about 500 micrometers in diameter, or the length of an amoeba) is fed through the center tube and extended just beyond the end of the capillary bundle. All of the materials are commercially available at pennies per unit.

The water-based solution (known as PBS) flows through the outer six capillaries while the center channel carries the phospholipid dissolved in alcohol (in production, the PBS would carry a drug or other cargo for the vesicles). A standard glass pipette attached to the end of the microfluidic device improves mixing by concentrating the ratio of water to lipid/alcohol.

"With our 3D capillary device, we can increase production of high-quality liposomes threefold from what our 2D planar system can do in the same amount of time," says NIST research chemical engineer Wyatt Vreeland, one of the authors on the Lab on a Chip paper.

*R. Hood, D. DeVoe, J. Atencia, W. Vreeland and D. Omiatek. A Facile Route to the Synthesis of Monodisperse Nanoscale Liposomes Using 3D Microfluidic Hydrodynamic Focusing in a Concentric Capillary Array. Lab on a Chip, May 2014. DOI:10.1039/C4LC00334A

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

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NCNR Neutrons Highlight Possible Battery Candidate

Analysis of a manganese-based crystal by scientists at the National Institute of Standards and Technology (NIST) and the Massachusetts Institute of Technology (MIT) has produced the first clear picture of its molecular structure. The findings could help explain the magnetic and electronic behavior of the whole family of crystals, many of which have potential for use in batteries.

crystal layers
At top of this image a, sodium fills in layers of the crystal, represented by one bright yellow dot followed by three darker ones; at bottom, the layers’ magnetic ordering is shown as green and purple dots representing magnesium at two different charge states, with the green-in-purple dots representing a mixture of the two charge states. Artwork generated from a scanning tunneling microscope image.
Credit: NIST
high resolution image

The family of crystals it belongs to has no formal name, but it has three branches, each of which is built around manganese, cobalt or iron—transition metals that can have different magnetic and charge properties. But regardless of family branch, its members share a common characteristic: They all store chemical energy in the form of sodium, atoms of which can easily flow into and out of the layers of the crystal when electric current is applied, a talent potentially useful in rechargeable batteries.

Other members of this family can do a lot of things in addition to energy storage that interest manufacturers: Some are low-temperature superconductors, while others can convert heat into electricity. The trouble is that all of them are, on the molecular level, messy. Their structures are so convoluted that scientists can't easily figure out why they do what they do, making it hard for a manufacturer to improve their performance.

Fortunately, this particular manganese crystal is an exception. "It's the one stable compound we know of in the manganese branch that has a perfect crystal lattice structure," says Jeff Lynn of the NIST Center for Neutron Research (NCNR). "That perfection means we can isolate all its internal electronic and magnetic interactions and see them clearly. So now, we can start exploring how to make those sodium atoms more movable."

Team members from MIT made the material and performed analysis using state-of-the-art lab techniques such as electron microscopy, but they needed help from the NCNR's neutron beams to tease out the interactions between its individual atoms. The effort showed that the crystal was unusual for reasons beyond its structural perfection. Its layers absorb sodium in a fashion rarely seen in nature: In each layer, one "stripe" of atoms fills up completely with sodium, then the next three stripes fill up only halfway before another full stripe appears. Lynn says the pattern is caused by different charges and magnetic moments that manganese atoms possess in different parts of the crystal, a feature revealed by analysis of the NCNR data.

"This particular crystal is probably not the one you'd use in a battery or some other application, it just permits us to understand what's happening with its internal structure and magnetism for the first time," Lynn says. "Now we have a basis for tailoring the properties of these materials by changing up the transition metals and changing the sodium content. We no longer have to hunt around in the dark and hope."

*X. Li, X. Ma, D. Su, L. Liu, R. Chisnell, S.P. Ong, H. Chen, A. Toumar, J-C. Idrobo, Y. Lei, J. Bai, F. Wang, J.W. Lynn, Y.S. Lee and G. Ceder. Direct Visualization of the Jahn-Teller Effect Coupled to Na Ordering in Na5/8MnO2. Nature Materials, DOI:10.1038/nmat3964, May 18, 2014.

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

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NIST Improves Performance, Capabilities of Its Computer Fire Modeling Tools

Sample analysis by NIST's Fire Dynamics Simulator predicts the evolution of an oxygen-starved heptane pool fire. Results are shown with NIST's Smokeview visualization software. Heptane is a colorless, flammable liquid and used as a solvent.

Credit: NIST

National Institute of Standards and Technology (NIST) scientists and engineers recently enhanced the capabilities of NIST's computer fire modeling software, a powerful suite of tools used worldwide in research, arson investigations, firefighter training, and development of fire-protection designs and standards.

The just-released sixth version of the NIST Fire Dynamics Simulator (FDS) features new algorithms and other problem-solving routines, more accurate methods for predicting smoke concentrations and soot deposition, a new turbulence model, and other significant improvements. NIST also added features to its Smokeview program for visualizing fire behavior and phenomena predicted by FDS.

Together, the fire modeling tools help to unravel the complex physics and chemistry of fire. Since they were first issued for public use in 2000, FDS and Smokeview have proved to be one of the most important advances in the field of fire protection research and engineering in the last decade.

FDS "has become the tool of choice by both the fire research and fire engineering communities," according to the International Forum of Fire Research Directors, an organization that promotes international cooperation in fire safety research. As a result, the forum says, "many new insights have emerged, further extending our understanding of the behavior of fire phenomena."

And as NIST and collaborators continue to improve the software tools' capabilities for predicting the spread, growth, and suppression of fire, use is spreading to a growing number of nations. Volunteer translation services for FDS and Smokeview support and documentation are offered in at least 15 languages.

The tools were essential to the NIST study that determined the factors that led to the collapse of the World Trade Center towers in the aftermath of the terrorist attacks on Sept. 11, 2001. The software also has aided reconstructions and experimental studies of fires in houses and high-rises, mines, aircraft cabins, nuclear facilities, road tunnels, movie theaters, parking garages, subway stations and more. In addition, FDS and Smokeview have been used to investigate circumstances in line-of-duty deaths of firefighters, and architects and engineers employ the tools when designing fire-protections systems for buildings and other structures.

FDS and Smokeview also are contributing to efforts to strengthen the scientific underpinnings of modern firefighting tactics and training. For example, the combination of fire experiments and computer modeling has greatly increased knowledge of how air flow influences the behavior of building fires. This understanding is leading to new tactics that improve the occupants' likelihood of survival and reduces hazards for first responders.

"Our aim is to bridge the gap between basic research and practical application, while maintaining the highest standards of scientific rigor," says Kevin McGrattan, the mathematician who is one of the leaders of the NIST fire modeling project. "At the same time, we are working to make the tools more accessible and useful to the entire fire-safety community."

To learn more about FDS and Smokeview, go to http://www.nist.gov/el/fire_research/fds_smokeview.cfm

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

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NIST Chip Produces and Detects Specialized Gas for Biomedical Analysis

A chip-scale device that both produces and detects a specialized gas used in biomedical analysis and medical imaging has been built and demonstrated at the National Institute of Standards and Technology (NIST). Described in Nature Communications,* the new microfluidic chip produces polarized (or magnetized) xenon gas and then detects even the faintest magnetic signals from the gas.

xenon chip
Illustration of NIST chip that makes polarized xenon gas. Xenon atoms (green) are loaded into the chamber on the left. The xenon flows into the next chamber, where the atoms are polarized through collisions with rubidium atoms (red) that are illuminated with circularly polarized light. Then the xenon flows into the smaller chamber, where its polarization is measured, using the rubidium atoms in the same chamber as magnetometers. Atoms exit the chip from the chamber on the far right.
Credit: NIST
high resolution image

Polarized xenon—with the atoms' nuclear "spins" aligned like bar magnets in the same direction—can be dissolved in liquids and used to detect the presence of certain molecules. A chemical interaction with target molecules subtly alters the magnetic signal from the xenon; by detecting this change researchers can identify the molecules in a complex mixture. Polarized xenon is also used as a contrast agent to enhance images in experimental magnetic resonance imaging (MRI) of human lungs, but conventional systems for producing and using this gas can be as big as a car.

Researchers from NIST and three other institutions developed the new chip, which might be used to reduce the size and cost of some instruments that, like MRI, rely on nuclear magnetic resonance (NMR). The chip's sensitive internal detector boosts the response of microfluidic NMR on small samples and eliminates the need for the powerful magnets associated with larger NMR devices such as those used in MRI. The microfabricated chip could be mass produced and integrated easily with existing microfluidic systems.

"We envision this device being an element in a more complex microfluidic NMR system, maybe for medical diagnostics," NIST physicist and co-author John Kitching says.

The new device is related to NIST's chip-scale magnetometer** but has additional capabilities and different applications, Kitching notes. Like the older NIST device, the new chip uses rubidium atoms as magnetometers to detect the xenon polarization, but they also multitask. The novel design also uses the rubidium atoms to polarize the xenon atoms, boosting their NMR response, and mixes the two types of atoms in the same chamber at the detection stage, which enhances the signal strength 500-fold.

The device is housed in a silicon and glass chip about 3centimeters long with four small chambers connected by microchannels. In one chamber, circularly polarized light transfers angular momentum to the rubidium atoms' electrons. The rubidium atoms then exchange spin with the nuclei of the xenon atoms, enhancing their polarization and hence the NMR signal.

The polarized xenon and rubidium atoms then flow into a detection chamber. Thanks to the atoms' magnetic interactions the sensor can detect weak signals corresponding to fewer than 1 trillion polarized xenon atoms, a result competitive with low-field optical magnetometry.

The combination of a xenon polarizer and detector in the same device, together with the extraordinary sensitivity of the chip device, could help make polarized xenon technology portable and less expensive for biomedical and other applications outside research laboratories.

The new chip was fabricated and demonstrated at NIST. Co-authors from Lawrence Berkeley National Laboratory, the University of California at Berkeley and Bar-Ilan University in Israel collaborated on the project, which was supported in part by the U.S. Department of Energy.

*R. Jiménez-Martínez, D.J. Kennedy, M. Rosenbluh, E.A. Donley, S. Knappe, S.J. Seltzer, H.L. Ring, V.S. Bajaj and J. Kitching. Optical hyperpolarization and NMR detection of 129Xe on a microfluidic chip. 2014. Nature Communications. Published online May 20.
**See 2012 NIST Tech Beat article, "NIST Mini-sensor Measures Magnetic Activity in Human Brain," at www.nist.gov/pml/div688/brain-041912.cfm.

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

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22 Organizations Seek the 2014 Baldrige Award

Twenty-two top-level candidates are lining up for a shot at being named one of America's best examples of performance excellence and innovation via the 2014 Malcolm Baldrige National Quality Award. This year's applicants include two service businesses, two educational organizations, 12 health care organizations and six nonprofits.

Once again in 2014, Baldrige-driven performance excellence proves to be popular within the health care sector. At least one health care organization in the United States has received a Baldrige Award annually since 2002. Also notable this year is the return of applicants in the service business category, an unbroken string in education (there have been applicants in this category each year since its start in 1999) and the continued strong showing for nonprofits (second only to health care among sectors represented in recent years).

Based on a change in eligibility requirements enacted in 2012, Baldrige Award applicants must first receive a performance excellence award from a state/local or sector-specific Baldrige-based program before seeking the national honor.

Working in teams over the summer, members of the volunteer board of Baldrige examiners will evaluate applicant organizations against the seven categories of the 2013–2014 Baldrige Criteria for Performance Excellence: leadership; strategic planning; customer focus; measurement, analysis and knowledge management; workforce focus; operations focus; and results. Examiners provide each applicant with 300 to 1,000 hours of review and a detailed report on the organization's strengths and opportunities for improvement.

In late August, the Baldrige Performance Excellence Program (BPEP)'s Panel of Judges will determine which organizations will receive site visits by examiner teams to verify information in the application and clarify questions that come up during the review. From those site-visited organizations, the 2014 Baldrige Award recipients will be selected in late November 2014.

BPEP is managed by the National Institute of Standards and Technology (NIST) in cooperation with the private sector. The program raises awareness about the importance of performance excellence in driving the U.S. and global economy; provides organizational assessment tools and criteria; develops and educates leaders in all types of organizations about the practices of national role models (in fact, BPEP recently ranked first among U.S. government and military organizations for leadership training*); and recognizes them with the Baldrige Award in six categories: manufacturing, service, small business, health care, education and nonprofit.

Thousands of organizations worldwide use the Baldrige Criteria to guide their operations, improve performance and get sustainable results. This proven improvement and innovation framework offers organizations an integrated approach to key management areas. The criteria are regularly updated to reflect the leading edge of validated management practice.

The Baldrige Award is not given for specific products or services. Since 1988, 101 awards have been presented to 95 organizations (with six repeat honorees). For more information on the Baldrige Program, go to www.nist.gov/baldrige.

*See"Baldrige Program Named Top Leadership Developer in Government," NIST Tech Beat, April 14, 2014.

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

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Automated Guided Vehicles Ripe for Standardized Performance Tests

Automated guided vehicles—or AGVs—are robotic versions of draft animals, hauling heavy loads and navigating their way in factories, distribution centers, ports and other facilities. These modern beasts of burden are evolving so rapidly in capabilities and electronic intelligence that the need for the equivalent of standardized performance testing has become apriority for the fast-growing AGV industry and its customers.

NIST storeroom AGV
Operating autonomously, the NIST AGV is removes a crate from an industrial rack. AGV is used in the development of safety and performance metrics and test methods for the manufacturing applications.
Credit: Bostelman/NIST
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Responding to that need is precisely the aim of a new ASTM International standards committee chaired by Roger Bostelman, a National Institute of Standards and Technology (NIST) electronics engineer who specializes in intelligent control systems technologies. Bostelman has been a strong advocate for developing voluntary, industry-consensus standards for measuring—and comparing—what AGVs can do.

He spent the last two years discussing the merits of common methods for assessing performance with AGV manufacturers, component suppliers and users of the technology. In those exchanges and in a "white paper,"Bostelman made it clear that standard test methods are industry-shared tools for evaluating and comparing performance—and not specifications dictating the design or manufacture of AGVs.

Standards, metrics, and test methods will be driven by requirements articulated by end-users and AGV manufacturers, Bostelman says.

"There are many benefits to be gained," he explains. "Prospective customers would be able to compare how well AGV products fit their manufacturing and distribution needs. This reduces the risk of investing in and implementing a new technology. So performance standards can help to expand the market. The standards also will allow AGV manufacturers to report the results of performance tests as a marketing tool."

AGV safety standards are already well in hand, thanks to the work of a committee formed by the American National Standards Institute and the Industrial Truck Standards Development Foundation. But Bostelman, who serves on the committee, says the committee's safety standards do not directly address task performance and intelligence. As examples of potential performance standards, he lists tests for measuring how well an AGV navigates around obstacles and docks at a series of specified stops and metrics for evaluating how vehicles perform under different environmental conditions such as rough or smooth surfaces and variations in temperature and lighting.

After a series of meetings, key stakeholders became convinced of the value of standard tests. And in late April 2014, ASTM's board of directors approved the creation of ASTM Committee F45 on Driverless Automatic Guided Industrial Vehicles. The new committee will focus on developing common terminology, recommended practices, guides, tests and performance standards.

A U.S. invention, AGVs have been used since the 1950s, but adoption has been gradual. More than 3,000 of these driverless systems—ranging from one vehicle to more than 100—are estimated to have been installed in the United States over the last 50 years. But the market is beginning to take off. Inc. magazine included AGVs on its list of best industries for starting a business in 2014.

A burst of innovation over the last decade has spawned a growing variety of AGVs, from towing carts and forklift-like vehicles to small shelf-moving robots and haulers of massive loads. Computer-controlled and, usually, battery powered, AGVs negotiate their way using flexible, easy-to-reconfigure guidance technologies that include optical sensors, lasers, surface-mounted magnetic tape, and inertial guidance.

To learn more about the new standards committee, read "Steering a New Course" in ASTM International's Standardization News at: www.astm.org/standardization-news/features/steering-a-new-course-mj14.html.

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

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NIST Awards 19 Advanced Manufacturing Technology Planning Grants

The National Institute of Standards and Technology (NIST) today awarded 19 advanced manufacturing technology planning grants totaling $9 million to new or existing industry-driven consortia to develop technology roadmaps aimed at strengthening U.S. manufacturing and innovation performance across industries.

amtech photo composite
Awarded to 19 industry-driven partnerships, NIST advanced manufacturing technology planning grants will support technology roadmapping efforts across a wide spectrum of industries and processes. The images provide a sampling. Starting clockwise, from top left: welding, simulation of a blast furnace used in steel manufacturing, direct metal laser sintering, and additive manufacturing.
Credits: Welding: EWI; Blast furnace: University of Purdue Calumet; Sintering: EOS; Additive manufacturing: Young/NIST
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The grants, awarded to universities and other nonprofit organizations, are the first conferred by NIST's new Advanced Manufacturing Technology Consortia (AMTech) Program. They range from $378,900 to $540,000 for a period of up to two years.

The funded projects will identify and rank research and development goals, define workforce needs, and initiate other steps toward speeding technology development and transfer and improving manufacturing capabilities. Project collaborations span a wide variety of industries and technologies, from flexible-electronics manufacturing to biomanufacturing and from pulp-and-paper manufacturing to forming and joining technologies.

"The AMTech awards provide incentives for partnerships to tackle the important jobs of planning, setting strategic manufacturing technology goals, and developing a shared vision of how to work collaboratively to get there," said NIST Director Patrick Gallagher. "These are essential first steps toward building the research infrastructure necessary to sustain a healthy, innovative advanced manufacturing sector—one that invents, demonstrates, prototypes and produces here, in the U.S."

Technology roadmapping is a key component of all funded projects. Each consortium will engage manufacturers of all sizes, university researchers, trade associations and other stakeholders in an interactive process to identify and prioritize research projects that reduce shared barriers to the growth of advanced manufacturing in the United States.

In conjunction with developing technology roadmaps, the projects will undertake related tasks such as defining challenges specific to building robust domestic supply chains and establishing skill-set requirements for an advanced manufacturing workforce.

Established in 2013, the AMTech program aims to catalyze partnerships between U.S. industry, academia, and government that will support efforts to meet the long-term research needs of U.S. industry. A specific objective is to enable new—or to strengthen existing—industry-led technology consortia for the purpose of identifying and prioritizing research projects that reduce barriers to the growth of advanced manufacturing.

On July 24, 2013, the program announced its inaugural competition for planning grants. It received 82 applications seeking a total of $37.4 million in funding. Of the 19 consortia that received grants, 11 are new efforts that will be launched with AMTech funding. Applications for these projects included letters of commitment from companies and other prospective partners.

To read summaries of the AMTech-funded projects and to see maps showing the locations of the projects' lead organizations and their funded partners, go to www.nist.gov/amo/fundedawards.cfm.

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

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New NIST Guidelines Aim to Help IT System Developers Build Security In From the Ground Up — Public Comments Welcomed

A new initiative by computer security experts at the National Institute of Standards and Technology (NIST) seeks to bring widely recognized systems and software engineering principles to bear on the problem of information system security.

The goal, according to computer scientist Ron Ross, a NIST Fellow, is to help establish processes that build security into IT systems from the beginning using sound design principles, rather than trying to tack it on at the end. “We need to have the same confidence in the trustworthiness of our IT products and systems that we have in the bridges we drive across or the airplanes we fly in,” says Ross.

Civil engineers employ the principles of physics and engineering to build reliable structures, Ross says. Similarly, systems security engineering processes, supported by the fields of mathematics, computer science and systems/software engineering, can provide the discipline and structure needed to produce IT components and systems that enjoy the same level of trust and confidence.

NIST has launched a four-stage process to develop detailed guidelines for “systems security engineering,” adapting a set of widely used international standards for systems and software engineering* to the specific needs of security engineering. The agency has released the first set of those guidelines for public comment in a new draft document, Systems Security Engineering: An Integrated Approach to Building Trustworthy Resilient Systems.**

The NIST engineering-driven guidelines are meant to be broadly applicable to systems design in both the public and private sectors, for small and large systems, and for many different types of applications including general-purpose financial systems, defense systems and the industrial control systems used in power plants and manufacturing.

The current draft—and the first stage of the planned process—describes the fundamentals of systems security engineering, elements and concepts and covers 11 core technical processes in systems and software development. Later public drafts will add material in supporting appendices, for example, on principles of security, trustworthiness and system resilience; use case scenarios; and important nontechnical processes such as risk management and quality control procedures. NIST expects to publish the final, complete version of the engineering guidelines by December 2014.

The initial public draft of Systems Security Engineering: An Integrated Approach to Building Trustworthy Resilient Systems is available at http://csrc.nist.gov/publications/PubsDrafts.html#800-160. Public comments on the current draft are requested by July 11, 2014, and should be sent to sec-cert@nist.gov.

*International Organization for Standardization (ISO), the International Electrotechnical Commission (IEC), and the Institute of Electrical and Electronic Engineers (IEEE) standard 15288:2008, Systems and software engineering — System life cycle processes.
**R. Ross, J.C. Oren and M. McEvilley. Systems Security Engineering: An Integrated Approach to Building Trustworthy Resilient Systems. NIST Special Publication 800-160. Initial Public Draft. May 2014.

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

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NIST Seeks Comments on Major Revision to Industrial Control Systems Security Guide

The National Institute of Standards and Technology (NIST) has issued for public review and comment a proposed major update to its Guide to Industrial Control Systems (ICS) Security.*

manufacturing worker
Credit: ©Minerva Studio-Fotolia_com

Most industrial control systems began as proprietary, stand-alone collections of hardware and software that were separated from the rest of the world and isolated from most external threats. Today, widely available software applications, Internet-enabled devices, and other IT offerings have been integrated into many systems, and the data produced in ICS operations are increasingly used to support business decisions. This connectivity has delivered many benefits, but it also has increased the vulnerability of these systems to malicious attacks, equipment failures and many other threats.

Downloaded more than 2.5 million times since its initial release in 2006, the NIST guide advises on how to reduce the vulnerability of computer-controlled industrial systems used by industrial plants, public utilities and other major infrastructure operations to malicious attacks, equipment failures, errors, inadequate malware protection and other software-related threats.

The new draft—the second revision of the guide—includes updates to sections on ICS threats and vulnerabilities, risk management, recommended practices, security architectures, and security capabilities and tools for ICS.

Due to their unique performance, reliability and safety requirements, securing industrial control systems often requires adaptations and extensions to security controls and processes commonly used in traditional IT systems. Recognizing this, a significant addition to the draft is a new appendix offering tailored guidance on how to adapt and apply security controls and control enhancements detailed in the 2013 comprehensive update of Security and Privacy Controls for Federal Information Systems and Organizations (NIST Special Publication 800-53, revision 4) to ICS. SP 800-53 contains a baseline set of security controls that can be tailored for specific needs according to an organization's mission, operational environment, and the technologies used. The new draft Guide to Industrial Control Systems (ICS) Security includes an ICS overlay that adapts and refines that baseline to address the specialized security needs of utilities, chemical companies, food manufacturers, automakers and other users of industrial control systems.

The Guide to Industrial Control System (ICS) Security, Revision2 Initial Public Draft (NIST SP 800-82) can be downloaded from the NIST Computer Security Resource Center at: http://csrc.nist.gov/publications/drafts/800-82r2/sp800_82_r2_draft.pdf. The public comment period runs from May 14 through July 18, 2014. Comments may be submitted by mail to: National Institute of Standards and Technology; Attn: Computer Security Division, Information Technology Laboratory; 100 Bureau Drive (Mail Stop 8930) Gaithersburg, MD 20899-8930; or by email to: nist800-82rev2comments@nist.gov

*K. Stouffer, S. Lightman, V. Pillitteri, M. Abrams and A. Hahn. Guide to Industrial Control Systems (ICS) Security. NIST Special Publication 800-82 Revision 2, Initial Public Draft. May 2014.

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

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