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Displaying 201 - 225 of 2028

Study of the Reactions of OH with HCl, HBr, and HI between 298 K and 460 K.

November 24, 2020
Author(s)
Vladimir L. Orkin, Victor Khamaganov, Igor Larin
The reactions between OH radicals and hydrogen halides (HCl, HBr, HI) have been studied between 298 K to 460 K by using a discharge flow – electron paramagnetic resonance technique. The rate constants at room temperature were found to be kHCl(298 K) = (7.9

Lessons From the NIST Micronutrients Quality Assurance Program for Vitamin C, 1993 to 2015: Sample Stability, Assay Reproducibility, and Use of Controls to Improve Comparability

November 11, 2020
Author(s)
David L. Duewer, Jeanice M. Brown Thomas, Katherine E. Sharpless, S A. Margolis
Vitamin C is a necessary micronutrient that is involved in many biological processes. In preserved human plasma and serum, vitamin C is most meaningfully analyzed as total ascorbic acid (TAA). From 1993 through 2015, the National Institute of Standards and

Conformational gating, dynamics and allostery in human monoacylglycerol lipase

October 28, 2020
Author(s)
Sergiy Tyukhtenko, Girija Rajarshi, Ioannis Karageorgos, Nikolai Zvonok, Kiran Vemuri, Jeffrey W. Hudgens, Xiaoyu Ma, Mahmoud L. Nasr, Alexandros Makriyannis, Kyle Anderson, Jason J. Guo, Gerhard Wagner
Inhibition of human Monoacylglycerol Lipase (hMGL) offers a novel approach for treating neurological diseases. The design of inhibitors, targeting active-inactive conformational transitions of the enzyme, can be aided by understanding the interplay between

Development of a pregnancy-specific reference material for thyroid biomarkers, vitamin D, and nutritional trace elements in serum

October 24, 2020
Author(s)
Ashley Russell, Lisa Kilpatrick, Carolyn Burdette, Denise S. Tevis, Zachary A. Fultz, Michael Nelson, Jeff M. Jarrett, Stephen A. Wise, Brittany Kassim, Stephen E. Long
Background Concentrations of critical metabolites, hormones, and nutritional elements change significantly throughout pregnancy. Therefore, increased matrix complexity is a challenge for the measurement of these biomarkers. To provide a quality assurance

Certification of Standard Reference Material(R) 955d, Toxic Elements and Metabolites in Frozen Human Blood

October 15, 2020
Author(s)
Lee L. Yu, Karen E. Murphy, Colleen E. Bryan Sallee, Thomas W. Vetter, Robert C. Hagwood, George C. Caceres, Stephen E. Long, J M. Jarrett, M A. Franklin, J Castro Georgi, D M. Jones, Robert Jones, Z Li, Y L. Sommer, D S. Tevis, K Wallon, C D. Ward, M Maras, S Erdahl, C Gilmer, M Wermers, H Woldeysus, K F. Mehigan, M Morrissette, Christopher D. Palmer, Patrick J. Parsons
Standard Reference Material (SRM) 955d is intended for use in validating analytical methods for measuring toxic elements and mercury species in human blood, and in value assigning locally produced control materials analyzed using the validated methods. A

NIST/NIH Vitamin D Metabolites Quality Assurance Program (VitDQAP): Final Report

September 16, 2020
Author(s)
Katrice A. Lippa, Mary Bedner, Susan Tai, Carolyn Q. Burdette
The National Institute of Standards and Technology (NIST) established a Vitamin D Metabolites Quality Assurance Program (VitDQAP) in collaboration with the National Institutes of Health Office of Dietary Supplements (NIH-ODS) in 2009. The VitDQAP at NIST

Method development in interaction polymer chromatography

September 1, 2020
Author(s)
Andre M. Striegel
Interaction polymer chromatography (IPC) is an umbrella term covering a large variety of primarily enthalpically-dominated macromolecular separation methods. These include temperature- gradient interaction chromatography, interactive gradient polymer

Proposal: Let's Develop a Community Consensus K-ratio Database

August 30, 2020
Author(s)
Nicholas Ritchie, Dale E. Newbury, John Fournelle, Aurelien Moy, Heather Lowers, Anette von der Handt, Paul Carpenter, Emma Bullock, John Donovan
The electron excited microanalysis community is increasingly running into the limitations of its ability to derive accurate an composition from measured x-ray intensities. Many of these limitations could be mitigated if the standard matrix correction

Polycyclic Aromatic Hydrocarbon Structure Index

August 12, 2020
Author(s)
Lane C. Sander, Stephen A. Wise
NIST Special Publication (SP) 922 is an aid in the identification of the chemical structures of polycyclic aromatic hydrocarbons (PAHs). The Structure Index consists of two parts: (1) a cross index of named PAHs listed in alphabetical order and (2)

An untargeted approach to determine the authenticity of Ginkgo biloba L. plant materials and dried leaf extracts by liquid chromatography-mass spectrometry (LC-HRMS) and chemometrics.

August 5, 2020
Author(s)
Meryl B. Cruz, Benjamin Place, Laura J. Wood, Aaron A. Urbas, Werickson Rocha, Andrzej Wasik
The lack of stringent regulations regarding raw materials for herbal supplements used for medicinal purposes has been a constant challenge in the industry. Ginkgo biloba L. leaf extracts attract consumers because of the supposed positive effect on mental

The Art in Science of MicroTAS 2019†

July 28, 2020
Author(s)
Gregory A. Cooksey
The 2019 MicroTAS conference (the 23rd International Conference of Miniaturized Systems for Chemistry and Life Sciences) held in Basel, Switzerland, brought great opportunities to viewinspiring microscale compositions. Many of the best images were

Increasing the Coverage of a Mass Spectral Library of Milk Oligosaccharides Using a Hybrid- Search-Based Bootstrapping Method and Milks from a Wide Variety of Mammals

July 8, 2020
Author(s)
Concepcion A. Remoroza, Tytus D. Mak, Yuri A. Mirokhin, Sergey L. Sheetlin, Xiaoyu Yang, Stephen E. Stein, Power L. Michael, San Andres V. Joice, Yuxue Liang
This study significantly expands both the scope and method of identification for construction of a previously reported tandem mass spectral library of 74 human milk oligosaccharides (HMOs) derived from results of LC-MS/MS experiments. In the present work

Determination of molecular mass 302 polycyclic aromatic hydrocarbons in Standard Reference Material 1597a by reversed-phase liquid chromatography and constant energy synchronous fluorescence spectroscopy

July 3, 2020
Author(s)
Hugh V. Hayes, Walter B. Wilson, Anthony M. Santana, Andres D. Campiglia, Lane C. Sander, Stephen A. Wise
High-performance liquid chromatography with fluorescence detection is often used for the analysis of polycyclic aromatic hydrocarbons (PAH) in environmental extracts. Since fluorescence chromatograms are usually recorded at a single set of excitation and
Displaying 201 - 225 of 2028