An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Stephen E. Long, Michael B. Ellisor, Frances Nilsen, Laura J. Wood, Karen E. Murphy, Lee L. Yu
Highly toxic metals such as arsenic, cadmium, lead and mercury are prevalent in the terrestrial and marine environments from both natural sources and anthropogenic activities. Contamination of food can often occur during agricultural production and food
Michael T. Postek, Dianne L. Poster, Andras Vladar, Mark S. Driscoll, Jay A. LaVerne, Zios Tsinas, Mohamad Al-Sheikhly
Nanocellulose is a high value material that has gained increasing attention because of its high strength, stiffness, unique photonic and piezoelectric properties, high stability and uniform structure. Through utilization of a biorefinery concept
Christopher T. Sempos, Stephen Wise, Karen W. Phinney, Susan Tai, Johanna Camara, Gary L. Myers, Ramon Durazo-Arvizu, Lu Tian, John H. Eckfeldt, Andrew N. Hoofnagle, W. Greg Miller, Lorin M. Bachmann, Ian S. Young, J Pettit, G. Caldwell, A Liu, S P. Brooks, K. Sarafin, M. Thamm, C. Scheidt-Nave, G. B. Mensink, M. Busch, M. Rabenberg, Kevin Cashman, Mairead Kiely, Michael Kinsella, K Galvan, J. Y. Zhang, K OH, S. W. Lee, C. L. Jung, L. Cox, G. Goldberg, K. Guberg, S. Meadows, A. Prentice, G. Swan, A. Tedstone, Graham D. Carter, Julia C. Jones, P. Brannon, R. M. Lucas, P. M. Crump, Glenville Jones, E. Cavalier, Joyce Merkel, J. M. Betz
The Vitamin D Standardization Program (VDSP) coordinated an interlaboratory study to assess the comparability of measurements of total 25-hydroxyvitamin D [25(OH)D] in human serum, which is the primary marker of vitamin D status. A set of 50 individual
The National Institute of Standards and Technology (NIST) has established a Vitamin D Metabolites Quality Assurance Program (VitDQAP) in collaboration with the National Institutes of Health (NIH) Office of Dietary Supplements. Participants in the twelfth
Susan Tai, Michael Nelson, Brian Lang, Karen W. Phinney, Lane C. Sander, James H. Yen, J. M. Betz, Christopher T. Sempos, Stephen Wise
The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health, Office of Dietary Supplements (NIH-ODS) and the Vitamin D Standardization Program (VDSP), has recently issued a new serum-matrix Standard
Phase equilibria of fluid mixtures are important in numerous industrial applications and are, thus, a major focus of thermophysical property research. Improved data, particularly along the dew line, are needed to improve model predictions. Here we present
Jorge O. Ona Ruales, Lane C. Sander, Walter Brent Wilson, Stephen Wise
The relationship of reversed-phase liquid chromatography retention on a polymeric C18 stationary phase and the shape of polycyclic aromatic hydrocarbons (PAHs) was investigated for three-ring to seven-ring cata-condensed isomers. We report the first
The quest for a reliable means to detect cannabis intoxication with a br eathalyzer is ongoing. In order to design such a device, it is important to understand the basic fundamental thermodynamics of the compounds of interest. Herein, the vapor pressures
Li-Hong Xu, E. M. Reid, B. Guislain, Jon T. Hougen, Eugene A. Alekseev, I. Krapivin
Quantum chemistry packages can be used to predict with reasonable accuracy spin-rotation hyperfine interaction constants for methanol, which contains one methyl-top internal rotor. In this work we used these same packages to calculate components of the
In this paper we examine the two-dimensional tunneling formalism used previously to fit the hydrogen-transfer and internal-rotation splittings in the microwave spectrum of 2 methylmalonaldehyde in an effort to determine the origin of various
Jennifer R. Verkouteren, Jeffrey A. Lawrence, Edward R. Sisco
A new approach was developed to prepare particle standards of the explosive 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) for use in quantitative wipe sampling studies. Screening activities to detect traces of explosives are heavily focused on wipe
Dublin, Ireland beheld The 20th International Conference of Miniaturized Systems for Chemistry and Life Sciences (MicroTAS 2016) from October 23 to 27, 2016. The conference not only included a great technical program, but also outreach activities, an
Chemical measurement methods are designed to promote accurate knowledge of a measurand or system and, as such, often allow elicitation of latent sources of variability and correlation in experimental data. They typically implement measurement equations
Jennifer R. Verkouteren, Jeffrey A. Lawrence, Matthew E. Staymates, Edward R. Sisco
One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common procedure for collecting traces of explosives, and standardized measurements of collection efficiency
In this article, we review the progress in the area of electrochemical technology with Lewis acidic haloaluminate room-temperature ionic liquids (RTILs), such as AlCl31-ethyl-3-methylimidazolium chloride and AlBr31-ethyl-3- methylimidazolium bromide, and
Secondary fluorescence, the final term in the familiar matrix correction triumvirate Z·A·F, is the most challenging for Monte Carlo models to simulate. In fact, only two implementations of Monte Carlo models commonly used to simulate electron probe x-ray
Recent advances in instrumentation for Secondary Ion Mass Spectrometry (SIMS) have focused on the application of polyatomic primary ions for enhancing molecular secondary ion signals of organic materials. A few studies have also noted that some polymers
Nearly fifty years ago, two landmark papers appeared that should have cured the problem of ambiguous uncertainty statements in published data. Eisenharts paper in Science called for statistically meaningful numbers, and Curries Analytical Chemistry paper
We use First-principles density functional theory total energy and linear response phonon calculations to compute the Helmholtz and Gibbs free energy as a function of temperature, pressure, and cell volume in the flexible metal-organic framework material
John Bowden, Jacqueline T. Bangma, Martin Jones, Russell H. Lowers, Frances Nilsen, Jessica L. Reiner, Thomas R. Rainwater, Stephen E. Somerville, Louis J. Guillette Jr.
This study aimed to quantify fourteen perfluoroalkyl acids (PFAAs) in the plasma of a population of alligators located at Merritt Island national Wildlife Refuge (MINWR). Male (n = 117) and female (n = 112) alligators were sampled in every month during
Stacy Schuur, Paul R. Becker, Colleen E. Bryan Sallee, Rebecca Pugh, Jared Ragland, Jessica Reiner, Jennifer Hoguet, Michele M. Schantz
The USA's Marine Environmental Specimen Bank (ESB) has archived marine wildlife collections dating back to 1976. Numerous lessons have been learned including collecting the correct species and tissues for environmental contaminant monitoring, developing
Tara Lovestead, Jessica L. Burger, Nico Schneider, Thomas J. Bruno
Commercial and military aviation is faced with challenges that include high fuel costs, emissions, and supply chain security that result from the reliance on petroleum-based feedstocks. The development of alternative gas turbine fuels from renewable