Government College

About: Government College is a based out in . It is known for research contribution in the topics: Population & Ring (chemistry). The organization has 4481 authors who have published 5986 publications receiving 57398 citations.

Trimethyl chitosan and its applications in drug delivery.

Abstract: Chitosan, a polymer obtained by deacetylation of chitin is widely studied for its pharmaceutical and nonpharmaceutical applications. Recommendations about uses of this polymer although could not be always realized due to limited solubility. Chitosan, for example, has been extensively evaluated for its mucoadhesive and absorption enhancement properties. The positive charge on the chitosan molecule gained by acidic environment in which it is soluble seems to be important for absorption enhancement. However chitosan is not soluble in medium except below pH 5.6. This limits its use as permeation enhancer in body compartments where pH is high. In this regard there is a need for chitosan derivatives with increased solubility, especially at neutral and basic pH values. Trimethylation of chitosan is an effort in this direction. Despite the abundance of the research related to trimethyl chitosan (TMC), the overview of the topic is not available. Hence an attempt is made in this review to cover the recent findings pertaining to synthesis, characterization and applications of TMC especially in pharmaceutical field. TMC has been synthesized by different ways and characterized by FTIR, NMR, DSC etc. This quaternized derivative of chitosan possesses a positive charge and is soluble over a wide range of pH. TMC, being a derivative of cationic polymer enriched with positive charge shows better mucoadhesive, permeation enhancement, drug delivery and DNA delivery properties. TMC can be further derivitized or grafted for modulating properties as solubility, cytotoxicity or cell recognition ability. Apart from these applications, TMC itself and its derivatives exhibit antimicrobial properties also. Quaternization of chitosan not only with methyl group but higher group as ethyl or along with spacer or quaternization of modified chitosan can be of interest too.

Anisotropic spheres with variable energy density in general relativity

Abstract: Interior solutions of Einstein field equations for anisotropic spheres with variable energy density are obtained. The solutions for uniform energy density [10] and for radial pressure equal to zero [11] are particular cases of the present solution. With this solution we are also able to discuss an anisotropic gas sphere. Physically it explains larger red-shifts of different quasi-stellar objects. The results of the model have been used to explain the behaviour of a neutron stars and conclude that the maximum mass of a neutron star does not exceed two solar masses, which confirms the Chandrasekhar limit.

Eco-friendly preparation of zinc oxide nanoparticles using Tabernaemontana divaricata and its photocatalytic and antimicrobial activity.

Abstract: The present work reports the green synthesis of Zinc Oxide Nanoparticles (ZnO NPs) using aqueous Tabernaemontana divaricata green leaf extract. ZnO NPs have been characterized by X-ray diffraction (XRD), Ultra Violet–Visible (UV–Vis) studies, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform–Infra Red (FT–IR) analysis. XRD pattern analysis confirms the presence of pure hexagonal wurtzite crystalline structure of ZnO. The TEM images reveal the formation of spherical shape ZnO NPs with the sizes ranging from 20 to 50 nm. The FT–IR analysis suggests that the obtained ZnO NPs have been stabilized through the interactions of steroids, terpenoids, flavonoids, phenyl propanoids, phenolic acids and enzymes present in the leaf extract. Mechanism for the formation of ZnO NPs using Tabernaemontana divaricata as bioactive compound is proposed. As prepared ZnO NPs reveals antibacterial activity against three bacterial strains, Salmonella paratyphi, Escherichia coli and Staphylococcus aureus. The ZnO NPs shows higher antibacterial activity against S. aureus and E. coli and lesser antibacterial activity against S. paratyphi compared to the standard pharmaceutical formulation. Photocatalytic activity of synthesized ZnO NPs was analyzed for methylene blue (MB) dye degradation with sunlight. Almost complete degradation of dye occurred in 90 min. This nano-ZnO, prepared by eco-friendly method will be much useful for dye removal and bacterial decontamination.

Estimation of lattice strain in nanocrystalline silver from X-ray diffraction line broadening

Abstract: The lattice strain contribution to the X-ray diffraction line broadening in nanocrystalline silver samples with an average crystallite size of about 50 nm is studied using Williamson-Hall analysis assuming uniform deformation, uniform deformation stress and uniform deformation energy density models. It is observed that the anisotropy of the crystallite should be taken into account, while separating the strain and particle size contributions to line broadening. Uniform deformation energy density model is found to model the lattice strain appropriately. The lattice strain estimated from the interplanar spacing data are compared with that estimated using uniform-energy density model. The lattice strain in nanocrystalline silver seems to have contributions from dislocations over and above the contribution from excess volume of grain boundaries associated with vacancies and vacancy clusters.