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Jones, Christopher M.

Publications and source records attributed to Jones, Christopher M..

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Toxicity, Tolerability, and Compliance of Concurrent Capecitabine or 5-Fluorouracil in Radical Management of Anal Cancer With Single-dose Mitomycin-C and Intensity Modulated Radiation Therapy: Evaluation of a National Cohort

Chemoradiation therapy (CRT) with mitomycin C (MMC) and 5-fluorouracil (5-FU) is established as the standard of care for the radical treatment of patients with anal squamous cell carcinoma (ASCC). The use of the oral fluoropyrimidine-derivative capecitabine is emerging as an alternative to 5-FU despite limited evidence of its tolerability and toxicity.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Genomics and Ecology of Novel N 2 O-Reducing Microorganisms

Microorganisms with the capacity to reduce the greenhouse gas nitrous oxide (N 2 O) to harmless dinitrogen gas are receiving increased attention due to increasing N 2 O emissions (and our need to mitigate climate change) and to recent discoveries of novel N 2 O-reducing bacteria and archaea. The diversity of denitrifying and nondenitrifying microorganisms with capacity for N 2 O reduction was recently shown to be greater than previously expected. A formerly overlooked group (clade II) in the environment include a large fraction of nondenitrifying N 2 O reducers, which could be N 2 O sinks without major contribution to N 2 O formation. Finally, we review the recent advances about fundamental understanding of the genomics, physiology, and ecology of N 2 O reducers and the importance of these findings for curbing N 2 O emissions.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2008

Multilayer Piezoelectric Stack Actuator Characterization

Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

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