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Displaying 11851 - 11875 of 73751

Magnetic Resonance Imaging Biomarker Calibration Service: Proton Spin Relaxation Times

May 3, 2018
Author(s)
Michael A. Boss, Andrew M. Dienstfrey, Zydrunas Gimbutas, Kathryn E. Keenan, Jolene D. Splett, Karl F. Stupic, Stephen E. Russek
This document describes the calibration service to measure proton spin relaxation times, T1 and T2, of materials used in phantoms (calibration artifacts) to verify the accuracy of MRI-based quantitative measurements. Proton spin relaxation times are used

Nail to Nail Fingerprint Challenge: Prize Analysis

May 3, 2018
Author(s)
Gregory P. Fiumara, Elham Tabassi, Patricia A. Flanagan, John D. Grantham, Kenneth Ko, Karen Marshall, Matthew Schwarz, Bryan Woodgate, Christopher Boehnen
In September 2017, the Intelligence Advanced Research Projects Activity held a fingerprint data collection as part of the Nail to Nail Fingerprint Challenge. Participating Challengers deployed devices designed to collect an image of the full nail to nail

SiC power MOSFET gate oxide breakdown reliability Current status

May 3, 2018
Author(s)
Kin P. Cheung
SiC power MOSFET is poised to take off commercially. Gate oxide breakdown reliability is an important obstacle standing is the way. Early prediction of poor intrinsic reliability comparing to silicon MOSFET, while theoretically sound, has now proven way

A Faraday-shielded, DC Stark-free optical lattice clock

May 2, 2018
Author(s)
Kyle P. Beloy, Xiaogang Zhang, William F. McGrew, Nathan M. Hinkley, Tai H. Yoon, Daniele Nicolodi, Robert J. Fasano, Stefan A. Schaeffer, Roger C. Brown, Andrew D. Ludlow
We demonstrate the absence of a DC Stark shift in an ytterbium optical lattice clock. Stray electric fields are suppressed through the introduction of an in-vacuum Faraday shield. Still, the effectiveness of the shielding must be experimentally assessed

Bound electron nonlinearity beyond the ionization threshold

May 2, 2018
Author(s)
Jared K. Wahlstrand, Sina Zahedpour, Anand Bahl, Miroslav Kolesik, H M. Milchberg
Although high field laser-induced ionization is a fundamental process at the root of many applications, there have been no absolute measurements of its transient rate. Such information is crucial, for example, for understanding the propagation of high

A 3D-printed alkali metal dispenser

May 1, 2018
Author(s)
Eric B. Norrgard, Daniel S. Barker, James A. Fedchak, Nikolai N. Klimov, Julia K. Scherschligt, Stephen P. Eckel
We demonstrate and characterize a source of Li atoms made from direct metal laser sintered Ti. The source's outgassing rate is measured to be $5 \,(2)\cdot 10^{-7}$\,$\rm{Pa}~ \rm{L}~ \rm{s}^{-1}$ at the temperature which optimizes the number of atoms

An optical clock to go

May 1, 2018
Author(s)
Andrew D. Ludlow
Bringing next-generation atomic clocks out of the lab is not an easy task, but doing so will unlock many new possibilities. As a crucial first step, a portable atomic clock has now been deployed for relativistic geodesy measurements in the Alps.

Burning Velocities of Marginally Flammable Refrigerant-Air Mixtures

May 1, 2018
Author(s)
Gregory T. Linteris
Refrigerant working fluids have been predicted to be large contributors to the increase in radiative forcing of the earth. Consequently, existing compounds will soon be phased out. Low- GWP replacements exist, but they tend to be mildly flammable, and

Generalized Sheet Transition Conditions (GSTCs) for a Metascreen

May 1, 2018
Author(s)
Christopher L. Holloway
Using the multiple-scales homogenization method, we derive generalized sheet transition conditions (GSTCs) for electromagnetic fields at the surface of a metascreen---a metasurface with a ``fishnet'' structure. These surfaces are characterized by

NIST Spectroscopic Measurement Standards

May 1, 2018
Author(s)
Paul C. DeRose, Kenneth D. Cole, Aaron Urbas, Steven J. Choquette, Evelyn Solis, Erica V. Stein, John E. Schiel, Brian Lang, Hua-Jun He
Ultraviolet (UV) absorbance measurements provide a rapid and reliable method to determine protein concentrations. The National Institute of Standards and Technology (NIST) has developed Standard Reference Material (SRM) 2082as a pathlength standard for UV

Oxidatively-induced DNA damage and base excision repair in euthymic patients with bipolar disorder

May 1, 2018
Author(s)
Deniz Ceylan, Gamze Tuna, Guldal Kirkali, Zeliha Tunca, Gunes Can, Hidayet E. Arat, Melis Kant, Miral M. Dizdar, Aysegul Ozerdem
Oxidatively-induced DNA damage has previously been associated with bipolar disorder. More recently, impairments in DNA repair mechanisms have also been reported. We aimed to investigate oxidatively-induced DNA lesions and expression of DNA glycosylases
Displaying 11851 - 11875 of 73751
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