Turbulent Compressible Convection with Rotation - Penetration above a Convection Zone

We perform Large eddy simulations of turbulent compressible convection in stellar-type convection zones by solving the Navi\'{e}r-Stokes equations in three dimensions. We estimate the extent of penetration into the stable layer above a stellar-type convection zone by varying the rotation rate ({\boldmath$\rm\Omega$}), the inclination of the rotation vector ($\theta$) and the relative stability ($S$) of the upper stable layer. The computational domain is a rectangular box in an f-plane configuration and is divided into two regions of unstable and stable stratification with the stable layer placed above the convectively unstable layer. Several models have been computed and the penetration distance into the stable layer above the convection zone is estimated by determining the position where time averaged kinetic energy flux has the first zero in the upper stable layer. The vertical grid spacing in all the model is non-uniform, and is less in the upper region so that the flows are better resolved in the region of interest. We find that the penetration distance increases as the rotation rate increases for the case when the rotation vector is aligned with the vertical axis. However, with the increase in the stability of the upper stable layer, the upward penetration distance decreases. Since we are not able to afford computations with finer resolution for all the models, we compute a number of models to see the effect of increased resolution on the upward penetration. In addition, we estimate the upper limit on the upward convective penetration from stellar convective cores.Comment: Accepted for Publication in Asttrophysics & Space Scienc

Chemical composition and antibacterial activity of essential oil from fruit of <i>Micromelum integerrimum (Buch.</i>-<i>Ham. ex DC.) Wight & Arn. ex M. Roem</i>

<p>The essential oil extracted from fruit of <i>Micromelum integrrimum</i> were evaluated through gas chromatography and gas chromatography-mass spectroscopy. 52 compounds were identified from the fruit oil representing 99.98% of the oil. The major components of the total fruit oil are monoterpene hydrocarbons (72.23%), oxygenated monoterpenes (14.78%) and sesquiterpene (11.54%) which were predominated by terpinolene (32.21%), α-pinene (17.24%), β-pinene (17.24%), and camphene (4.05%). Moreover, other components that present in 1.45% were aromatic compounds, fatty acid, etc. The essential oil exhibited broad spectrum antimicrobial activity which is concentration dependent and 100 μL of the fruit oil showed the inhibition zones ranging from 7–16 mm. Fruit oil exhibited strong inhibition activity compared to standard anti-bacterial drug neomycin B (22 mm) against <i>Bacillus subtilis</i> MTCC 441 and <i>Bacillus spizizenii</i> ATCC 6633. This is the first hand report on the chemical profiles and promising anti-microbial activity of <i>Micromelum integrrimum</i> fruit essential oil towards <i>Basillus Sp.</i></p

Bio-transformation of artemisinin using soil microbe: Direct C-acetoxylation of artemisinin at C-9 by Penicillium simplissimum

Potent antimalarial compound artemisinin, 1 was bio-transformed to C-9 acetoxy artemisinin, 2 using soil microbe Penicillium simplissimum along with C-9 hydroxy derivative 3. The products were characterized using high field NMR and MS–MS data. The absolute stereochemistry of the newly generated chiral centers has been ascertained by COSY and 1D NOESY experiments. This is the first Letter of direct C-acetoxylation of artemisinin using microbial strains

Study of phospholipid bilayers supported on chitosan-titanium nitride coatings produced by plasma immersion ion implantation (PIII)

FONDECYT 1170261 1141105 Postdoctoral Fellowship FONDECYT 3160803 3160179 FONDECYT INICIACION 11160664 CONICYT-PIA ACT 1108 140