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Tech Beat - November 14, 2012

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Editor: Michael Baum
Date created: November 14, 2012
Date Modified: November 14, 2012 
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Silver Anniversary Baldrige Awards Honor Organizations in Four Sectors

The U.S. Commerce Department today named four U.S. organizations as recipients of the 2012 Malcolm Baldrige National Quality Award, the nation’s highest Presidential honor for performance excellence through innovation, improvement and visionary leadership. The winners in this, the 25th anniversary year of the award, represent four different sectors, one repeat recipient and a health network recognized for the same honor earned previously by its flagship hospital.

Lockheed Martin Missiles and Fire Control
Assembler Judy Betts works on the power supply for a fire control radar at 2012 Baldrige Award winner Lockheed Martin Missiles and Fire Control. For more images, go to www.nist.gov/baldrige/baldrige_recipients2012.cfm and select the company names.
Credit: Courtesy of Lockheed Martin Missiles and Fire Control

The 2012 Baldrige Award recipients—listed with their category—are:

MESA previously received a small business Baldrige Award in 2006. Another 2006 award winner, North Mississippi Medical Center in the health care category, is the primary hospital of this year’s much larger recipient, North Mississippi Health Services.

"The four organizations recognized with the 2012 Baldrige Award are leaders in the truest sense of the word and role models that others in the health care, nonprofit and business sectors worldwide will strive to emulate,” said Acting U.S. Secretary of Commerce Rebecca Blank. “They have set the bar high for innovative practices, dynamic management, financial performance, outstanding employee and customer satisfaction, and, most of all, for their unwavering commitment to excellence and proven results.”

For the first time this year, the Baldrige Performance Excellence Program (BPEP) is recognizing best practices in one or more of the Baldrige Criteria categories by organizations that are candidates for the award but are not selected as a winner.* This year, the Baldrige judges have chosen to honor the following organizations (listed with the criteria for which they are being acknowledged):

  • Maury Regional Medical Center, Columbia, Tenn. (strategic planning, workforce focus)
  • Northwest Vista College, San Antonio, Texas (leadership, customer focus)
  • PricewaterhouseCoopers Public Sector Practice, McLean, Va. (leadership, workforce focus)

The 2012 Baldrige Award recipients are expected to be presented with their awards at an April 2013 ceremony in Baltimore, Md.

The BPEP is managed by the National Institute of Standards and Technology (NIST) in cooperation with the private sector. It also is a partner in the Baldrige Enterprise, which includes the private-sector Baldrige Foundation, the Alliance for Performance Excellence—a body made up of the 33-plus state, local, regional and sector-specific Baldrige-based programs serving nearly all 50 states; and ASQ, an international organization promoting quality.

The Baldrige Award is not given for specific products or services. Since 1988, 93 organizations have received the award.

For more details, including profiles of the 2012 Baldrige Award recipients, see the Nov. 14, 2012, news announcement, “Four U.S. Organizations Honored with the 2012 Baldrige National Quality Award,” at http://www.nist.gov/baldrige/baldrige_recipients2012.cfm.

* See “Baldrige Award Applicants Can Now Receive Recognition for Best Practices” at www.nist.gov/baldrige/baldrige-062712.cfm.

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

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'Cloning' Could Make Structurally Pure Nanotubes for Nanoelectronics

Researchers from the University of Southern California (USC) and the National Institute of Standards and Technology (NIST) have demonstrated a technique for growing virtually pure samples of single-wall carbon nanotubes (SWCNTs) with identical structures, a process they liken to "cloning" the nanotubes.* If it can be suitably scaled up, their approach could solve an important materials problem in nanoelectronics: producing carbon nanotubes of a specific structure to order.

nanotube cloning
Cloning nanotubes: In this computer model, small, pre-selected nanotube "seeds" (yellow) are grown to long nanotubes of the same twist or "chirality" in a high-temperature gas of small carbon compounds.
Credit: Courtesy USC
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Single-wall carbon nanotubes are hollow cylinders of carbon atoms bound together in a hexagonal pattern, usually about a nanometer in diameter. One fascinating feature of nanotubes is that there are many ways to wrap the hexagon sheet into a cylinder, from perfectly even rows of hexagons that wrap around in a ring, to rows that wrap in spirals at various angles—"chiralities," to be technical. Even more interesting, chirality is critical to the electronic properties of carbon nanotubes. Some structures are electrical conductors—essentially a nanoscale wire—others are semiconductors.

"Experts in the electronics industry believe that single-wall carbon nanotubes are a promising option for nanoelectronics—semiconductor devices beyond today's CMOS technology," says NIST materials scientist Ming Zheng, "But for that particular application, the structure is critically important. A fundamental issue in that field is how to make single-wall nanotubes with a defined structure."

The problem is that methods for manufacturing carbon nanotubes, which often use a metal catalyst to initiate growth, usually produce a mixture of many different chiralities or twists—along with a lot of junk that's just soot. A lot of research has concentrated on schemes for "purifying" the batch to extract one particular kind of nanotube. And also you have to get rid of the catalyst.

The team led by Zheng and Professor Chongwu Zhou of USC took a different tack. NIST researchers had developed a technique for extracting nanotubes of a specific twist from a solution by using specially tailored DNA molecules that bind to one particular nanotube chirality.** The DNA trick is very selective, but unfortunately only works well with fairly short pieces of nanotube.

"That approach laid the foundation for this work," says Zheng. "We are using the short purified nanotubes to grow bigger structures of the same kind. We call it 'cloning', like cloning an organism from its DNA and a single cell, but in this case, we use a purified nanotube as a seed."

Small segments of nanotubes of identical chirality, extracted using the DNA technique, were put in a high-temperature reaction chamber at USC with methane gas, which breaks down in the heat to smaller carbon molecules that attach themselves to the ends of the nanotubes, gradually building them up—and preserving their structural chirality. "A bit like building a skyscraper," Zheng observes, though in these early experiments, the tubes are laying on a substrate.

"I think the most important thing this work shows is that from a chemistry point of view, it's entirely possible to grow nanotubes without a catalyst, and even maintain control of the structure," says Zheng, "It's a different approach, to do the separation first to obtain the 'seeds' and then do the synthesis to grow the desired nanotubes."

The research was funded in part by the Semiconductor Research Corporation's Focus Center Research Program, Functional Engineered Nano Architectonics, and the Office of Naval Research.

* J. Liu, C. Wang, X.Tu, B. Liu, L. Chen, M. Zheng and C. Zhou. Chirality-controlled synthesis of single-wall carbon nanotubes using vapor phase epitaxy. Nature Communications, 3, Article number: 1199.  doi:10.1038/ncomms2205.
** See, for example, the Aug. 2, 2011, NIST news item, "Armchair Science: DNA Strands That Select Nanotubes Are First Step to a Practical 'Quantum Wire'" at www.nist.gov/public_affairs/tech-beat/tb20110802.cfm#dna.

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

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NIST Study Suggests Carbon Nanotubes May Protect DNA from Oxidation

Researchers at the National Institute of Standards and Technology (NIST) have provided evidence in the laboratory that single-wall carbon nanotubes (SWCNTs) may help protect DNA molecules from damage by oxidation. In nature, oxidation is a common chemical process in which a reactive chemical removes electrons from DNA and may increase the chance for mutations in cells. More studies are needed to see if the in vitro protective effect of nanotubes reported in the laboratory also occurs in vivo, that is, within a living organism.

nanotubes
Scanning electron microscope image of a typical sample of the NIST single-wall carbon nanotube soot standard reference material. Recent NIST research suggests that, at least in the laboratory, carbon nanotubes may help protect DNA molecules from damage by oxidation. The image shows an area just over a micrometer wide. (Color added for clarity.)
Credit: Vladar, NIST
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"Our findings don't tell us whether carbon nanotubes are good or bad for people and the environment," says Elijah Petersen, one of the authors of the study. "However, the results do help us better understand the mechanisms by which nanotubes might interact with biomolecules."

Single-wall carbon nanotubes—tiny hollow rods that are one-atom-thick sheets of graphene rolled into cylinders 10,000 times smaller in diameter than a human hair—are prized for their extraordinary optical, mechanical, thermal and electronic properties. They are being used to produce lightweight and extremely strong materials, enhance the capabilities of devices such as sensors, and provide a novel means of delivering drugs with great specificity. However, as carbon nanotubes become increasingly incorporated into consumer and medical products, the public concern about their potential environmental, health and safety (EHS) risks has grown. Scientifically determining the level of risk associated with the carbon nanotubes has been challenging, with different studies showing conflicting results on cellular toxicity. One of the components lacking in these studies is an understanding of what physically happens at the molecular level.

In a recent paper,* NIST researchers investigated the impact of ultrasonication on a solution of DNA fragments known as oligomers in the presence and absence of carbon nanotubes. Ultrasonication is a standard laboratory technique that uses high-frequency sound waves to mix solutions, break open cells or process slurries. The process can break water molecules into highly reactive agents such as hydroxyl radicals and hydrogen peroxide that are similar to the oxidative chemicals that commonly threaten mammalian cell DNA, although the experimental levels from sonication are much greater than those found naturally within cells. "In our experiment, we were looking to see if the nanotubes enhanced or deterred oxidative damage to DNA," Petersen says.

Contrary to the expectation that carbon nanotubes will damage biomolecules they contact, the researchers found that overall levels of accumulated DNA damage were significantly reduced in the solutions with nanotubes present. "This suggests that the nanotubes may provide a protective effect against oxidative damage to DNA," Petersen says.

A possible explanation for the surprising result, Petersen says, is that the carbon nanotubes may act as scavengers, binding up the oxidative species in solution and preventing them from interacting with DNA. "We also saw a decrease in DNA damage when we did ultrasonication in the presence of dimethyl sulfoxide (DMSO), a chemical compound known to be a hydroxyl radical scavenger," Petersen says.

Petersen says that a third experiment where ultrasonication was performed in the presence of DMSO and SWCNTs at the same time produced an additive effect, reducing the DNA damage levels more significantly than either treatment alone.

This research is part of NIST's work to help characterize the potential EHS risks of nanomaterials, and develop methods for identifying and measuring them.

* E.J. Petersen, X. Tu, M. Dizdaroglu, M. Zheng and B.C. Nelson. Protective roles of single-wall carbon nanotubes in ultrasonication-induced DNA base damage. Small (2012), DOI: 10/1002/smll.201201217.

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

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