27 research outputs found
Variable Winds and Dust Formation in R Coronae Borealis Stars
We have observed P-Cygni and asymmetric, blue-shifted absorption profiles in
the He I 10830 lines of twelve R Coronae Borealis (RCB) stars over short (1
month) and long (3 year) timescales to look for variations linked to their
dust-formation episodes. In almost all cases, the strengths and terminal
velocities of the line vary significantly and are correlated with dust
formation events. Strong absorption features with blue-shifted velocities ~400
km/s appear during declines in visible brightness and persist for about 100
days after recovery to maximum brightness. Small residual winds of somewhat
lower velocity are present outside of the decline and recovery periods. The
correlations support models in which recently formed dust near the star is
propelled outward at high speed by radiation pressure and drags the gas along
with it.Comment: AJ in press, 21 pages, 3 figure
Automated mitosis detection in histopathology based on non-gaussian modeling of complex wavelet coefficients
The effects of (+)-Gossypol on 11β-HSD and the concentration of corticosterone and dehydrocorticosterone in mice serum and tissues
11β-hydroxysteroid dehydrogenase (11β-HSD) plays an important part in mediating glucocorticoid action, catalyzing the interconversion of corticosterone (B) and dehydrocorticosterone (A) in rodents. The aim of our study is to investigate the effects of (+)-gossypol (G+) on 11β-HSD. Adult ICR mice were given B and B + (G+) by intraperitoneal injection. The activity of 11β-HSD was evaluated by measuring the ratio of A and B, meanwhile the effects of (+)-gossypol on the conversion rate of B to A was determined with HPLC. Serum A/B levels of the B+(G+) group decreased by 2.42, 7.32, 17.85, 31.39, and 40.02 % compared to the B group at each measured time interval. A/B levels at 1 h for the B + (G+) group decreased by 43.78, 21.29 and 34.47% in liver, kidney and adrenal glands, respectively, in comparison to the B group. However, (+)-gossypol had no effect on brain and testis. (+)-Gossypol was an inhibitor of 11β-HSD.Colegio de Farmacéuticos de la Provincia de Buenos Aire
The effects of (+)-Gossypol on 11β-HSD and the concentration of corticosterone and dehydrocorticosterone in mice serum and tissues
11β-hydroxysteroid dehydrogenase (11β-HSD) plays an important part in mediating glucocorticoid action, catalyzing the interconversion of corticosterone (B) and dehydrocorticosterone (A) in rodents. The aim of our study is to investigate the effects of (+)-gossypol (G+) on 11β-HSD. Adult ICR mice were given B and B + (G+) by intraperitoneal injection. The activity of 11β-HSD was evaluated by measuring the ratio of A and B, meanwhile the effects of (+)-gossypol on the conversion rate of B to A was determined with HPLC. Serum A/B levels of the B+(G+) group decreased by 2.42, 7.32, 17.85, 31.39, and 40.02 % compared to the B group at each measured time interval. A/B levels at 1 h for the B + (G+) group decreased by 43.78, 21.29 and 34.47% in liver, kidney and adrenal glands, respectively, in comparison to the B group. However, (+)-gossypol had no effect on brain and testis. (+)-Gossypol was an inhibitor of 11β-HSD.Colegio de Farmacéuticos de la Provincia de Buenos Aire
Simultaneous determination of cortisone and cortisol in serum by HPLC-DAD and application for pharmacokinetics
To develop a high performance liquid chromatography method for the simultaneous determination of cortisone and cortisol in rat serum and apply it for pharmacokinetics. After addition of pirfenidone as internal standard (IS), a liquid-liquid extraction with ethylacetate was employed for the sample preparation. Samples were separated on Zorbax SB-C18 column at 25 ºC using mobile phase consisting of acetonitrile-water-0.1 % trifluoroacetic acid with flow rate of 0.9 mL/min, utilizing DAD detection at 246 nm. Excellent liner relationships of the cortisone and cortisol concentrations were obtained from 50 to 6000 ng/mL, with r = 0.9997, 0.9999 respectively, and the lower limit of quantitation (LLOQ) were both 50 ng/mL. The developed method was successfully applied to pharmacokinetic studies of cortisone and cortisol in rats following single dose of 20 mg/kg via intraperitoneal injection.Colegio de Farmacéuticos de la Provincia de Buenos Aire
The effects of (+)-Gossypol on 11β-HSD and the concentration of corticosterone and dehydrocorticosterone in mice serum and tissues
11β-hydroxysteroid dehydrogenase (11β-HSD) plays an important part in mediating glucocorticoid action, catalyzing the interconversion of corticosterone (B) and dehydrocorticosterone (A) in rodents. The aim of our study is to investigate the effects of (+)-gossypol (G+) on 11β-HSD. Adult ICR mice were given B and B + (G+) by intraperitoneal injection. The activity of 11β-HSD was evaluated by measuring the ratio of A and B, meanwhile the effects of (+)-gossypol on the conversion rate of B to A was determined with HPLC. Serum A/B levels of the B+(G+) group decreased by 2.42, 7.32, 17.85, 31.39, and 40.02 % compared to the B group at each measured time interval. A/B levels at 1 h for the B + (G+) group decreased by 43.78, 21.29 and 34.47% in liver, kidney and adrenal glands, respectively, in comparison to the B group. However, (+)-gossypol had no effect on brain and testis. (+)-Gossypol was an inhibitor of 11β-HSD.Colegio de Farmacéuticos de la Provincia de Buenos Aire
Mudskipper genomes provide insights into the terrestrial adaptation of amphibious fishes
Mudskippers are amphibious fishes that have developed morphological and physiological adaptations to match their unique lifestyles. Here we perform whole-genome sequencing of four representative mudskippers to elucidate the molecular mechanisms underlying these adaptations. We discover an expansion of innate immune system genes in the mudskippers that may provide defence against terrestrial pathogens. Several genes of the ammonia excretion pathway in the gills have experienced positive selection, suggesting their important roles in mudskippers’ tolerance to environmental ammonia. Some vision-related genes are differentially lost or mutated, illustrating genomic changes associated with aerial vision. Transcriptomic analyses of mudskippers exposed to air highlight regulatory pathways that are up- or down-regulated in response to hypoxia. The present study provides a valuable resource for understanding the molecular mechanisms underlying water-to-land transition of vertebrates
Hypoxic tolerance of Chinese black sleeper Bostrichthys sinensis embryos at heartbeat stage
Tolerance of hypoxia in Chinese black sleeper (Bostrichtlyssinensis) embryos at heartbeat stage was examined at different oxygen concentrations. Embryonic response to hypoxic conditions was expressed in terms of the intensity, of variation in heartbeat rate (17). Exposure of the embryos at 25 degrees C to 0.5, 1.0 and 1.5 mg/l dissolved oxygen (DO), caused bradycardia, which was developed within the first 10 mill of hypoxia, followed by a plateau, and lasted until termination of the hypoxia. The V values were significantly affected by DO concentrations (P 0.05)