Steroids: a timeless fascination: cholesterol and its bio-​products

Steroids are solid org. compds. derived from all life forms, including microorganisms, plants and animals. They obtain their generic name 'steroids' from Greek: stereos = solid. Steroids encompass a wide variety of compds. of vital importance to life such as sterols, bile acids, sex hormones, anti-​inflammatory corticoid hormones, etc. Some of the important aspects of cholesterol, the principal sterol of higher animals are highlighted

A novel route for the synthesis of six- and seven-membered 6-trimethylsilylspiro4,nalk-6-enes

A novel route for the synthesis of 6-trimethylsilylspiro4,5dec-6-ene and 6-trimethylsilylspiro4,6undec-6-ene by the Wurtz-Fittig type coupling reaction of 6-iodospiro4,5dec-6-ene and 6-iodospiro4,6undec-6-ene with alkali metals and chlorotrimethylsilane in good yields is reported. The compounds serve as a new class of spiranyl cyclic vinylanionic synthons. © 2012 Bulgarian Academy of Sciences

Synthesis of Some Novel 1-​(Substituted Phenyl)​-​2-​(4-​(Trimethylsilyl)​-​1H-​1,​2,​3-​Triazol-​1-​yl) Ketones

A facile and highly efficient method for the regioselective one-​pot synthesis of a series of novel 1-​(substituted phenyl)​-​2-​(4-​(trimethylsilyl)​-​1H-​1,​2,​3-​triazol-​1-​yl)​ketones from 2-​bromo-​1-​(substituted phenyl)​ketones, sodium azide, and trimethylsilyl acetylene, through Cu (I) catalyzed 1,​3-​dipolar [3+2] cycloaddn. reaction is reported. The reaction proceeds smoothly in 40​% aq. acetone at room temp. without the use of any additive. Regioselectivity privileges the formation of the corresponding C-​4 silylated-​1,​2,​3-​triazoles in high yields in all instances. The methodol. offers an entry to new 1,​2,​3-​triazolyl-​4-​trimethylsilyl anionic synthon scaffolds

Vinylsilanes in synthesis: 2-Halo-lcyclopentenyl alkyl/aryl ketones from 2-halo-1-trimethylsilylcyclopentenes

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Examining Temporal Variation of the Fermi Coupling Constant using SNe Ia Light Curves

In standard model, the Fermi coupling constant, $G_F$, sets the strength of electroweak decay. We attempt an approach to constrain the temporal variation of the Fermi coupling constant $G_F$. To probe it, Type Ia supernovae (SNe Ia) light curves are being used as a source of reliable primordial nucleosynthesis events across the redshifts. We utilized studies suggesting that in the initial phase after the SNe Ia explosion, the electroweak decay of $^{56}Ni \rightarrow ^{56}Co \rightarrow ^{56}Fe$ is the key contributor to powering the SNe Ia light curve. We hence used the Pan-STARRS supernovae catalog having 1169 supernovae light curves in $g$, $r$, $i$, and $z$ spectral filters. The post-peak decrease in the apparent magnitude of light curves (in the rest frame of SNe) was related to the electroweak decay rate of primordial nucleosynthesis. Further, the decay rate relates to $G_F$. To keep the analysis independent of the cosmological model, we used the Hubble parameter measurement and a non-parametric statistical method, the Gaussian Process. Our study suggests a small yet finite temporal variation of $G_F$ and puts a strong upper bound on the present value of the fractional change in the Fermi coupling constant i.e; $\dfrac{\dot G_F}{G_F}\big\rvert_{z=0} \approx 10^{-11} yr^{-1}$ using datasets spread over a redshift range $0<z<0.75$.Comment: 14 pages, 7 figures, 1 tabl

Multidimensional Modeling of Direct Injection Diesel Engine with Split Multiple Stage Fuel Injections

AbstractIn the present study, an attempt has been made to predict the influence of split multiple stage fuel injection on a DI diesel engine performance and emission characteristics. The predictions have been made for both conventional continuous fuel injection as well as split multiple stage fuel injection. The analysis mainly emphasize on the prediction of SFC and NOx levels in a diesel engine for the above mentioned two fuel injection modes. These computational predictions can enhance the knowledge of the flow and combustion characteristics, which is of vital importance for the design and development of a high performance DI diesel engine. The aforementioned simulation work has been performed using a CFD code. It has been found that the split multiple stage fuel injection exhibits strong effects on combustion characteristics and provides controlled pressure and temperature inside the combustion chamber. It has also been seen that split multiple stage fuel injection significantly reduces the formation of NOx compared to that ofthe continuous fuel injection

Rapid Node Cardinality Estimation in Heterogeneous Machine-to-Machine Networks

Machine-to-Machine (M2M) networks are an emerging technology with applications in various fields, including smart grids, healthcare, vehicular telematics and smart cities. Heterogeneous M2M networks contain different types of nodes, e.g., nodes that send emergency, periodic, and normal type data. An important problem is to rapidly estimate the number of active nodes of each node type in every time frame in such a network. In this paper, we design two schemes for estimating the active node cardinalities of each node type in a heterogeneous M2M network with $T$ types of nodes, where $T \ge 2$ is an arbitrary integer. Our schemes consist of two phases-- in phase 1, coarse estimates are computed, and in phase 2, these estimates are used to compute the final estimates to the required accuracy. We analytically derive a condition for one of our schemes that can be used to decide as to which of two possible approaches should be used in phase 2 to minimize its execution time. The expected number of time slots required to execute and the expected energy consumption of each active node under one of our schemes are analysed. Using simulations, we show that our proposed schemes require significantly fewer time slots to execute compared to estimation schemes designed for a heterogeneous M2M network in prior work, and also, compared to separately executing a well-known estimation protocol designed for a homogeneous network in prior work $T$ times to estimate the cardinalities of the $T$ node types, even though all these schemes obtain estimates with the same accuracy.Comment: 14 pages, 21 figure

EVALUATION OF IMMUNOMODULATORY ACTIVITY OF PETROLEUM ETHER EXTRACT OF SEEDS OF PITHECELLOBIUM DULCE IN WISTAR RATS

Objective: The present study was planned to assess the immunomodulatory action of petroleum ether extracts of seeds of Pithecellobium dulce (PEPD) in experimental models of immunity.Methods: Metronidazole, pyrogallol and ethanol models were used for suppression of the immune system in Wistar rats. Humoral immunity was analyzed by haemmagglutination assay, whereas, cellular immunity was carried out by paw edema and carbon clearance assay. PEPD (400 mg/kg, p. o.) was selected by acute toxicity study. Levamisole (50 mg/kg, p. o.) was used as standard.Results: Metronidazole, pyrogallol and ethanol significantly decreased the humoral and cellular immunity, whereas, PEPD and levamisole significantly increased the circulating antibody titer in the indirect haemagglunation test. PEPD and levamisole also produced significant increases in paw edema and increase in the phagocytic index in the carbon clearance assay. Animals treated with metronidazole, pyrogallol and ethanol decreased in peripheral blood RBCs and monocytes whereas, PEPD and levamisole treated groups significantly increased in peripheral blood RBCs and monocytes.Conclusion: Our data showed that PEPD possesses potential for augmenting immune activity by cellular and humoral mediated mechanisms and also significantly restores the biochemical and histopathological parameters. The present study concluded that PEPD may have therapeutic and prophylactic value as immunostimulants.Â