Cochin University of Science and Technology

About: Cochin University of Science and Technology is a education organization based out in Kochi, Kerala, India. It is known for research contribution in the topics: Thin film & Natural rubber. The organization has 5382 authors who have published 7690 publications receiving 103827 citations. The organization is also known as: CUSAT & Cochin University.

Dynamic cumulative residual Renyi's entropy

Abstract: Recently, cumulative residual entropy (CRE) has been found to be a new measure of information that parallels Shannon's entropy (see Rao et al. [Cumulative residual entropy: A new measure of information, IEEE Trans. Inform. Theory. 50(6) (2004), pp. 1220–1228] and Asadi and Zohrevand [On the dynamic cumulative residual entropy, J. Stat. Plann. Inference 137 (2007), pp. 1931–1941]). Motivated by this finding, in this paper, we introduce a generalized measure of it, namely cumulative residual Renyi's entropy, and study its properties. We also examine it in relation to some applied problems such as weighted and equilibrium models. Finally, we extend this measure into the bivariate set-up and prove certain characterizing relationships to identify different bivariate lifetime models.

Polyaniline/graphene hybrid film as an effective broadband electromagnetic shield

Abstract: Conducting polyaniline (PANi)–graphene (G) free standing, hybrid films were obtained by a solution intercalation method suitable for electromagnetic interference (EMI) shielding applications. The films were characterized structurally using Fourier transform infrared spectroscopy, micro-Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The electrical characterization was done using Hall measurement setup to estimate the dc electrical conductivity and establish the charge carrier type and mobility and investigate the possibility of using the hybrid films in other applications. The thermal stability of the films was investigated using thermo gravimetric analysis. The EMI shielding effectiveness (SE) of the composite films was tested over a broad microwave frequency range covering 4–12 GHz (C and X bands) by waveguide transmission line technique. The films exhibit very high values of reflected power (Pr) in the range of 85–90% in the C-band and 75–80% in the X-band, respectively. A maximum total shielding effectiveness value of SET ∼ 42 dB could be observed in the frequency range of 4–8 GHz and SET ∼ 32 dB could be observed in the frequency range of 8–12 GHz, corresponding to more than 99.99% microwave attenuation in both the C and X bands. In the entire frequency range of analysis, contributions from reflection to the total EMI SE is very high compared to that of absorption. The results suggest that the hybrid film may be used as effective, lightweight and flexible, reflection dominated EMI shielding material in a broad range of electromagnetic spectrum.

Uptake of plasmid/glycosylated polymer complexes and gene transfer efficiency in differentiated airway epithelial cells.

Abstract: Background We have studied gene transfer efficiency of glycosylated polylysines and glycosylated polyethylenimines as vectors in immortalized differentiated airway gland serous cells and primary cultures of human airway surface epithelial cells. Methods In both cell types, lactosylated PEI was more efficient for gene transfer than unsubstituted PEI and lactosylated polylysine which requires the presence of endosomolytic agents. However, for all the vectors tested, gene transfer efficiency was lower in differentiated cells as compared with poorly differentiated cells. The presence of membrane lectins, i.e. cell surface sugar-specific receptors, was evaluated using fluorescein-conjugated neoglycoproteins and microscopy or flow cytometry. In differentiated airway surface epithelial cells, membrane lectins were not expressed and plasmid DNA/fluorescein-conjugated glycosylated polymer complexes were not incorporated. This accounted in part for the lack of gene transfer efficiency in these cells. In contrast, in differentiated airway gland serous cells, expression of lectins and their endocytotic properties appeared to be similar to that observed in undifferentiated cells, and plasmid DNA/fluorescein-conjugated glycosylated polymer complexes were incorporated in similar amounts by cells in both differentiated states. Results Glycosylated PEI appears to be a promising gene delivery system since it is more efficient than the sugar-free polymer and does not require endosomolytic agents. However, in differentiated airway gland serous cells, a low gene transfer efficiency was observed that could not be attributed to low expression of membrane lectins or low uptake of glycosylated complexes. An impaired intracellular trafficking of glycosylated complexes in differentiated airway gland serous cells is suggested. Copyright © 2002 John Wiley & Sons, Ltd.

Metabolites and bioactivities of Rhizophoraceae mangroves

Abstract: This review examines the chemical compositions and bioactivities of mangrove plants belonging to the Rhizophoraceae family. The Rhizophoraceae family of true mangrove plants is the most common and is also widely distributed species. It consists of 24 species across four genera. Of the 24 species, 12 species remain unexamined for their phytochemical constituents. There have been 268 metabolites reported from 16 species. The key phytochemical constituents identified across the family are the diterpenoids and triterpenoids. The major diterpenoids include pimaranes, beyeranes, kaurenes, dolabranes and labdanes whereas the significant triterpenoids are lupanes, dammaranes and oleananes. Disulphides, dolabranes and labdanes are considered to be the chemotaxonomic markers of the genera Bruguiera, Ceriops and Rhizophora respectively.