A Note on the Density Wave Model of the Galaxy

In this paper the general gas dynamical equations have been solved in the wave form and the general dispersion relation has been deduced. This dispersion relation has been used with simplifying assumptions plausible for special regions of the Galaxy, and results obtained have been shown to be able to interpret some observed dynamical behaviours as well as the distributional property of the gas in those special regions. For example, the analysis has yielded the interpretation of (a) the absence of any wave-pattern in the central region of the Galaxy, (b) the largescale deviation of the gas from the galactic plane in the outer regions of the Galaxy and (c) probably, the large-scale outflow of gas in the central region, as well as the large outward motion of the 3kpc arm. The analysis further indicates that in the solar neighbourhood the rotation curve of the Galaxy may possess a local maximum

A novel synthetic method for angularly functionalized polycyclic systems by vinylogous wolff rearrangement of β,γ-unsaturated diazoketones

Decompositions of the rigid polycylic β,γ-unsaturated diazomethyl ketones (la and b) and (2a and b) promoted by Cu(acac)2, Cu(OTf)2, Ni(acac)2 or silver benzoatetriethylamine in the presence of methanol are shown to give the respective rearranged γ,δ-unsaturated angularly substituted esters (3a and b) and (6a and b) along with other products

RESEARCH AND REVIEWS: JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES Exploring the Effect of Polyox on the Release Kinetics of a Model Antihypertensive Drug from a Cellulose Derivative Based Buccal Patch

ABSTRACT Drug release from matrix dosage form is affected by polymer swelling, it's erosion, drug distribution inside the matrix and polymeric combination. To prepare buccal controlled release patches hydrophilic, swellable, porous polymeric material alone or in optimum combination along with their buccoadhesive strength is essential. Here a plant derived gum like Gum karaya (GK) , a cellulose derivative-HPMCK15M and Polyox have been used to prepare buccal buccal patches of Carvedilol phosphate . The effect of Polyox and gum karaya on the release kinetics of drug from the buccal patches have been studied.The buccal patches were evaluated for it's physico-mechanical characteristics. The buccal patches revealed satisfactory physic-mechanical results. Buccoadhesive strength was found to be in the range of 31-35 gm, which is good enough to hold the buccal buccal patches inside the buccal cavity. Percent Swelling of the buccal patches were in the range of 449-529%.Swelling is maximum in the buccal patches where Polyox is present along with HPMCK15M and GK. Drug dissolution from the buccal patches has been described by kinetic models. The release data were fitted in different kinetic models, like zero order, first order and Higuchi. Release study of Buccal patches made up of only HPMCK15M followed zero order kinetics.. Buccal patches with GK along with HPMCK15M provided Higuchi kinetics over 8 hours of drug release.Further incorporating Polyox along with HPMCK15M and GK showed mixed order kinetics. Initially drug release followed Higuchi kinetics followed by zero order in the last phase

Chaperone-mediated inhibition of tubulin self-assembly

Molecular chaperones are known to play an important role in facilitating the proper folding of many newly synthesized proteins. Here, we have shown that chaperone proteins exhibit another unique property to inhibit tubulin self-assembly efficiently. Chaperones tested include α -crystallin from bovine eye lenses, HSP16.3, HSP70 from Mycobacterium tuberculosis and α -casein from milk. All of them inhibit polymerization in a dose-dependent manner independent of assembly inducers used. The critical concentration of MTP polymerization increases with increasing concentration of HSP16.3. Increase in chaperone concentration lowers the extent of polymerization and increases the lag time of self-assembly reaction. Although the addition of a chaperone at the early stage of elongation phase shows no effect on polymerization, the same concentration of chaperone inhibits polymerization completely when added before the initiation of polymerization. Bindings of HSP16.3 and α -casein to tubulin have been confirmed using isothermal titration calorimetry. Affinity constants of tubulin are 5.3 × 104 and 9.8 × 105 M-1 for HSP16.3 and α s-casein, respectively. Thermodynamic parameters indicate favourable entropy and enthalpy changes for both chaperones-tubulin interactions. Positive entropy change suggests that the interaction is hydrophobic in nature and desolvation occurring during formation of tubulin-chaperone complex. On the basis of thermodynamic data and observations made upon addition of chaperone at early elongation phase or before the initiation of polymerization, we hypothesize that chaperones bind tubulin at the protein-protein interaction site involved in the nucleation phase of self-assembly