438 research outputs found
Results of preoperative pulmonary function testing of adolescents with idiopathic scoliosis: A study of six hundred and thirty-one patients
Wavefront-Error Performance Characterization for the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Science Instruments
The science instruments (SIs) comprising the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) were tested in three cryogenic-vacuum test campaigns in the NASA Goddard Space Flight Center (GSFC)'s Space Environment Simulator (SES) test chamber. In this paper, we describe the results of optical wavefront-error performance characterization of the SIs. The wavefront error is determined using image-based wavefront sensing, and the primary data used by this process are focus sweeps, a series of images recorded by the instrument under test in its as-used configuration, in which the focal plane is systematically changed from one image to the next. High-precision determination of the wavefront error also requires several sources of secondary data, including 1) spectrum, apodization, and wavefront-error characterization of the optical ground-support equipment (OGSE) illumination module, called the OTE Simulator (OSIM), 2) F-number and pupil-distortion measurements made using a pseudo-nonredundant mask (PNRM), and 3) pupil geometry predictions as a function of SI and field point, which are complicated because of a tricontagon-shaped outer perimeter and small holes that appear in the exit pupil due to the way that different light sources are injected into the optical path by the OGSE. One set of wavefront-error tests, for the coronagraphic channel of the Near-Infrared Camera (NIRCam) Longwave instruments, was performed using data from transverse translation diversity sweeps instead of focus sweeps, in which a sub-aperture is translated and/or rotated across the exit pupil of the system. Several optical-performance requirements that were verified during this ISIM-level testing are levied on the uncertainties of various wavefront-error-related quantities rather than on the wavefront errors themselves. This paper also describes the methodology, based on Monte Carlo simulations of the wavefront-sensing analysis of focus-sweep data, used to establish the uncertainties of the wavefront-error maps
A Year of Wavefront Sensing with JWST in Flight: Cycle 1 Telescope Monitoring and Maintenance Summary
We summarize JWST's measured telescope performance across science Cycle 1.
The stability of segments alignments is typically better than 10 nanometers RMS
between measurements every two days, leading to highly stable point spread
functions. The frequency of segment "tilt events" decreased significantly, and
larger tilt events ceased entirely, as structures gradually equilibrated after
cooldown. Mirror corrections every 1-2 months now maintain the telescope below
70 nm RMS wavefront error. Observed micrometeoroid impacts during cycle 1 had
negligible effect on science performance, consistent with preflight
predictions. As JWST begins Cycle 2, its optical performance and stability are
equal to, and in some ways better than, the performance reported at the end of
commissioning.Comment: STScI Technical Memo. 2.5 pages text, 1 figur
Modified‐Release Subantimicrobial Dose Doxycycline Enhances Scaling and Root Planing in Subjects With Periodontal Disease
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142084/1/jper0440.pd
ER Stress Inhibits Liver Fatty Acid Oxidation while Unmitigated Stress Leads to Anorexia-Induced Lipolysis and Both Liver and Kidney Steatosis
The unfolded protein response (UPR), induced by endoplasmic reticulum (ER) stress, regulates the expression of factors that restore protein folding homeostasis. However, in the liver and kidney, ER stress also leads to lipid accumulation, accompanied at least in the liver by transcriptional suppression of metabolic genes. The mechanisms of this accumulation, including which pathways contribute to the phenotype in each organ, are unclear. We combined gene expression profiling, biochemical assays, and untargeted lipidomics to understand the basis of stress-dependent lipid accumulation, taking advantage of enhanced hepatic and renal steatosis in mice lacking the ER stress sensor ATF6α. We found that impaired fatty acid oxidation contributed to the early development of steatosis in the liver but not the kidney, while anorexia-induced lipolysis promoted late triglyceride and free fatty acid accumulation in both organs. These findings provide evidence for both direct and indirect regulation of peripheral metabolism by ER stress
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