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Displaying 1201 - 1225 of 2028

Development of a Candidate Reference Measurement Procedure for the Determination of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in Human Serum Using Isotope-Dilution Liquid Chromatography/Tandem Mass Spectrometry

February 5, 2010
Author(s)
Susan S. Tai, Mary Bedner, Karen W. Phinney
Vitamin D exists in two major forms, vitamin D3 and vitamin D2. Vitamin D helps the body absorb calcium and promote optimal growth. Both forms of vitamin D are metabolized to 25-hydroxyvitamin D in the body, and the levels of 25-hydroxyvitamin D3 (25-(OH

Microsensors in Dynamic Backgrounds: Toward Real-Time Breath Monitoring

January 15, 2010
Author(s)
Kurt D. Benkstein, Baranidharan Raman, Christopher B. Montgomery, C Martinez, Stephen Semancik
We evaluated MEMS microsensor array with chemi-resistive elements for use as a non-invasive clinical diagnostic tool to detect the presence or absence of trace amounts of disease biomarkers in simulated breath samples. The microsensor environment was

Symmetry and Fourier analysis of the ab-initio-determined torsional variation of structural and Hessian-related quantities for application to vibration-torsion-rotation interactions in CH3OH

January 11, 2010
Author(s)
Li-Hong Xu, Jon T. Hougen, Jonathan M. Fisher, Ronald M. Lees
The aim of the present paper is to investigate the use of quantum chemistry calculations to obtain the torsional dependence of various structural and vibrational-force-field-related quantities that could help in estimating the vibration-torsion-rotation

Architecture and Dynamics of C18 Bonded Interphases with Small Molecule Spacers

December 15, 2009
Author(s)
Lane C. Sander, Katrice A. Lippa, Catherine A. Rimmer, Maximilian Kuhnle, Volker Friebolin, Klaus Albert
The relationship between alkyl phase structure and chromatographic performance is investigated for a series of octadecyl (C18)- modified silica surfaces with defined spacing of the alkyl surface by a “pre-endcapping” technique. Stationary phases were

Nanoelectronic Fabrication with Flip Chip Lamination

December 15, 2009
Author(s)
Mariona Coll Bau, Curt A. Richter, Christina Hacker
Nanoelectronic fabrication with Flip chip lamination Mariona Coll, CA Richter, CA Hacker, Colloquium Catalan Institute of Nanoscience and Nanotechnology CIN2, Barcelona Spain, Dec 2009.

Thermal Stability of Confined Flip-Chip Laminated w-Functionalized Monolayers

December 3, 2009
Author(s)
Mariona Coll Bau, Curt A. Richter, Christina A. Hacker
We present the results of an IR study of the effect of temperature on the formation of Au-monolayer-Si molecular junctions by using a flip-chip lamination approach. Carboxylic acid-terminated alkanethiols self-assembled on ultrasmooth gold substrate have

Determination of Elements in SRM Soil 2709a by Neutron Activation Analysis

December 1, 2009
Author(s)
Rick L. Paul, Elizabeth A. Mackey, Rolf L. Zeisler, Rabia Oflaz, Bryan E. Tomlin
A combination of instrumental neutron activation analysis (INAA) and prompt gamma-ray activation analysis (PGAA) was used to value assign 35 elements in SRM soil 2709a (San Joaquin Soil). INAA with counting of short-lived radioisotopes was used for

Optimizing Acoustic Measurements of the Boltzmann Constant

November 22, 2009
Author(s)
Michael R. Moldover
We review the progress in acoustic metrology of gases that has occurred since the 1988 measurement of the universal gas constant R using a spherical acoustic resonator. The advances in understanding resonators and in calculating the thermophysical

Determination of Perfluorinated Alkyl Acid concentrations in Human Serum and Milk Standard Reference Materials

October 28, 2009
Author(s)
Jennifer M. Lynch, Antonia M. Calafat, Kayoko Kato, Mark E. Ellefson, William K. Reagen, Mark Strynar, Steven G. O'Connell, Craig M. Butt, Scott Mabury, Jeff Small, D.C.G. Muir, Stefan D. Leigh, Michele M. Schantz
Standard Reference Materials (SRMs) are homogeneous, well-characterized materials that are used to validate measurement methods and are critical in improving data quality. Disagreements in perfluorinated alkyl acid (PFAA) concentrations measured in

Effect of RP-1 Compositional Variability on Thermophysical Properties

October 6, 2009
Author(s)
Marcia L. Huber, Eric W. Lemmon, Thomas J. Bruno
We compare experimental and predicted thermophysical properties of two samples of rocket propellant RP-1 obtained from different batches of RP-1 that exhibit compositional variations. One sample is atypical, due to a high olefin content. The effect of the
Displaying 1201 - 1225 of 2028