53 research outputs found
Improved instrumental magnitude prediction expected from version 2 of the NASA SKY2000 master star catalog
The SKY2000 Master Star Catalog (MC), Version 2 and its predecessors have been designed to provide the basic astronomical input data needed for satellite acquisition and attitude determination on NASA spacecraft. Stellar positions and proper motions are the primary MC data required for operations support followed closely by the stellar brightness observed in various standard astronomical passbands. The instrumental red-magnitude prediction subsystem (REDMAG) in the MMSCAT software package computes the expected instrumental color index (CI) [sensor color correction] from an observed astronomical stellar magnitude in the MC and the characteristics of the stellar spectrum, astronomical passband, and sensor sensitivity curve. The computation is more error prone the greater the mismatch of the sensor sensitivity curve characteristics and those of the observed astronomical passbands. This paper presents the preliminary performance analysis of a typical red-sensitive CCDST during acquisition of sensor data from the two Ball CT-601 ST's onboard the Rossi X-Ray Timing Explorer (RXTE). A comparison is made of relative star positions measured in the ST FOV coordinate system with the expected results computed from the recently released Tycho Catalogue. The comparison is repeated for a group of observed stars with nearby, bright neighbors in order to determine the tracker behavior in the presence of an interfering, near neighbor (NN). The results of this analysis will be used to help define a new photoelectric photometric instrumental sensor magnitude system (S) that is based on several thousand bright star magnitudes observed with the PXTE ST's. This new system will be implemented in Version 2 of the SKY2000 MC to provide improved predicted magnitudes in the mission run catalogs
Using site-directed mutagenesis to probe the role of the D2 carotenoid in the secondary electron-transfer pathway of photosystem II
Phase 1 clinical trial of losmapimod in facioscapulohumeral dystrophy: Safety, tolerability, pharmacokinetics, and target engagement
Aims: Evaluate safety, tolerability, pharmacokinetics (PK) and target engagement (TE) of losmapimod in blood and muscle in facioscapulohumeral dystrophy (FSHD).Methods: This study included Part A: 10 healthy volunteers randomized to single oral doses of losmapimod (7.5 mg then 15 mg; n = 8) or placebo (both periods; n = 2); Part B: 15 FSHD subjects randomized to placebo (n = 3), or losmapimod 7.5 mg (n = 6) or 15 mg (n = 6); and Part C: FSHD subjects received open-label losmapimod 15 mg (n = 5) twice daily for 14 days. Biopsies were performed in FSHD subjects at baseline and Day 14 in magnetic resonance imaging-normal appearing (Part B) and affected muscle identified by abnormal short-tau inversion recovery sequence + (Part C). PK and TE, based on pHSP27:total HSP27, were assessed in muscle and sorbitol-stimulated blood.Results: PK profiles were similar between healthy volunteers and FSHD subjects, with mean C-max and AUC(0-12) for 15 mg in FSHD subjects (Part B) of 85.0 +/- 16.7 ng*h/mL and 410 +/- 50.3 ng*h/mL, respectively. Part B and Part C PK results were similar, and 7.5 mg results were approximately dose proportional to 15 mg results. Dose-dependent concentrations in muscle (42.1 +/- 10.5 ng/g [7.5 mg] to 97.2 +/- 22.4 ng/g [15 mg]) were observed, with plasma-to-muscle ratio from similar to 0.67 to similar to 1 at estimated t(max) of 3.5 hours postdose. TE was observed in blood and muscle. Adverse events (AEs) were mild and self-limited.Conclusion: Losmapimod was well tolerated, with no serious AEs. Dose-dependent PK and TE were observed. This study supports advancing losmapimod into Phase 2 trials in FSHD.Neurological Motor Disorder
Carotenoid and Pheophytin on Semiconductor Surface: Self-Assembly and Photoinduced Electron Transfer
In vivo hyperspectral confocal fluorescence imaging to determine pigment localization and distribution in cyanobacterial cells
Hyperspectral confocal fluorescence imaging provides the opportunity to obtain individual fluorescence emission spectra in small (≈0.03-μm3) volumes. Using multivariate curve resolution, individual fluorescence components can be resolved, and their intensities can be calculated. Here we localize, in vivo, photosynthesis-related pigments (chlorophylls, phycobilins, and carotenoids) in wild-type and mutant cells of the cyanobacterium Synechocystis sp. PCC 6803. Cells were excited at 488 nm, exciting primarily phycobilins and carotenoids. Fluorescence from phycocyanin, allophycocyanin, allophycocyanin-B/terminal emitter, and chlorophyll a was resolved. Moreover, resonance-enhanced Raman signals and very weak fluorescence from carotenoids were observed. Phycobilin emission was most intense along the periphery of the cell whereas chlorophyll fluorescence was distributed more evenly throughout the cell, suggesting that fluorescing phycobilisomes are more prevalent along the outer thylakoids. Carotenoids were prevalent in the cell wall and also were present in thylakoids. Two chlorophyll fluorescence components were resolved: the short-wavelength component originates primarily from photosystem II and is most intense near the periphery of the cell; and the long-wavelength component that is attributed to photosystem I because it disappears in mutants lacking this photosystem is of higher relative intensity toward the inner rings of the thylakoids. Together, the results suggest compositional heterogeneity between thylakoid rings, with the inner thylakoids enriched in photosystem I. In cells depleted in chlorophyll, the amount of both chlorophyll emission components was decreased, confirming the accuracy of the spectral assignments. These results show that hyperspectral fluorescence imaging can provide unique information regarding pigment organization and localization in the cell
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