Distribution and Attachment of Bryozoans in the Intertidal Region of South Andaman Island

Aiming to collate the distribution and the attachment preference of intertidal bryozoan of Andaman waters, a study was carried out in three intertidal sites (Burmanallah, Kodiyaghat, and Chidiytapu) of southeastern coasts of the Andaman Islands between June and August 2016. The present study is the first exclusive report on bryozoans from the Andaman Islands after a long research gap of nine decades. During our investigation, a total of twelve genera were identified from both calcareous and non-calcareous substratum. Out of the twelve genera, eight genera were new records from the island. The present study showed that the attachment affinity of the Bryozoans is more towards natural substratum particularly on the rocks. The Thalamoporella sp. reported the most abundant species with maximum average colony length of 3.5 cm from the rock substratum

Initiation of coconut cell suspension culture from shoot meristem derived embryogenic calli: A preliminary study

An attempt was made to establish highly competent embryogenic cell suspension culture in coconut, a species recalcitrant to in vitro culture. Embryogenic calli were initiated from shoot meristem explants of coconut. Y3 medium supplemented with 2.4-D (4.5 μM) and glutamine (34.2 μM) was found to be the best medium to initiate cell suspension. Growth evaluation was done by packed cell volume (PCV) and it was found that maximum growth volume of 9.9% was reached at 200 days of culture initiation. About 52% of viable cells were detected through fluorescent microscopy. Cell aggregation was noticed in Y3 medium supplemented with glutamine (34.2 μM), malt extract (100mg/l), biotin (40.9 μM) and kinetin (9.3 μM), but further progress could not be achieved. It was also observed that embryogenic calli were not of a friable type, but were associated with densely aggregated cells. Because of its hard nature, we were unsuccessful to obtain high quality cell suspension

Liver fluke vaccines: Vaccination Against Fasciolosis by a Multivalent Vaccine of Recombinant Stage-Specific Antigens

Fasciola\u27s excretory-secretory material comprises chiefly cathepsin B and cathepsin L. These cysteine proteases are proposed as major mediators of parasitism, and are considered targets for vaccination. In order to assess the vaccine efficacy of these enzymes, single and multivalent recombinant protein vaccinations of adult-stage F. hepatica cathepsin L5, metacercarial-stage F. gigantica cathepsin L1 g and juvenile-stage F. hepatica cathepsin B were analysed in rats against F. hepatica challenge infection. The protective efficacy of anti-fluke vaccines was evaluated in terms of parasitological parameters (recovered fluke burden, fluke body size and wet weight) and pathological changes (liver damage score) in rats. The rats vaccinated with recombinant proteins were shown to have significantly fewer and smaller flukes than the control rats. A maximum protection of 83% was seen in the group vaccinated with a combination of cathepsin B and cathepsin L5

Fabrication of cost-effective, highly reproducible large area arrays of nanotriangular pillars for surface enhanced Raman scattering substrates

Development of cost-effective, highly reproducible non-conventional fabrication techniques for anisotropic metal nanostructures is essential to realizing potential applications of plasmonic devices, photonic devices, and surface enhanced Raman scattering (SERS) phenomenon based sensors. This report highlights the fabrication of nanotriangle arrays via nanoimprinting to overcome difficulties in creating large-area SERS active substrates with uniform, reproducible Raman signals. Electron beam lithography of anisotropic nanostructures, formation of arrays of nanotriangles in silicon and the transfer of triangular shapes to polymethylmethacrylate (PMMA) sheets via nanoimprinting have not been reported elsewhere. The reuse of silicon masters offers potential for production of low cost SERS substrates. The SERS activity and reproducibility of nanotriangles are illustrated and a consistent average enhancement factor of up to ~2.9 × 1011, which is the highest value reported for a patterned SERS substrate, is achieved.Peer ReviewedPostprint (author's final draft

Domain matched epitaxial growth of Bi1.5Zn1Nb1.5O7 thin films by pulsed laser deposition

Bi1.5Zn1Nb1.5O7 (BZN) epitaxial thin films were grown by pulsed laser deposition on Al2O3 with a double ZnO buffer layer through domain matching epitaxy (DME) mechanism. The pole figure analysis and reciprocal space mapping revealed the single crystalline nature of the thin film. The pole figure analysis also shows a 60º twinning for the (222) oriented crystals. Sharp intense spots in the SAED pattern also indicate the high crystalline nature of BZN thin film. The Fourier filtered HRTEM images of the BZN-ZnO interface confirms the domain matched epitaxy of BZN with ZnO buffer. An electric field dependent dielectric tunability of 68% was obtained for the BZN thin films with inter digital capacitors patterned over the film

Electrical characterization of transparent p–i–n heterojunction diodes

Transparent p – i – n heterojunction diodes are fabricated using heavily doped, p-type CuYO₂ and semi-insulating i-ZnO thin films deposited onto a glass substrate coated with n-type indium tin oxide. Rectification is observed, with a ratio of forward-to-reverse current as high as 60 in the range −4–4 V. The forward-bias current–voltage characteristics are dominated by the flow of space-charge-limited current, which is ascribed to single-carrier injection into the i-ZnO layer. Capacitance measurements show strong frequency dispersion, which is attributed to i-ZnO traps. The diode structure has a total thickness of 0.75 μm and an optical transmission of ∼35%–65% in the visible region

Observation of room temperature photoluminescence from asymmetric CuGaO2/ZnO/ZnMgO multiple quantum well structures

Asymmetric (CuGaO2/ZnO/ZnMgO) and symmetric (ZnMgO/ZnO/ZnMgO) multiple quantum well (MQW) structures were successfully fabricated using pulsed laser deposition (PLD) and their comparison were made. Efficient room temperature photoluminescent (PL) emission was observed from these MQWs and temperature dependent luminescence of asymmetric and symmetric MQWs can be explained using the existing theories. A systematic blue shift was observed in both MQWs with decrease in the confinement layer thickness which could be attributed to the quantum confinement effects. The PL emission from asymmetric and symmetric MQW structures were blue shifted compared to 150 nm thick ZnO thin film grown by PLD due to quantum confinement effects

Transparent p-type conducting CuScO₂₊ₓ films

Transparent films of CuScO₂₊ₓ have been prepared which show p-type electrical conductivity. The temperature dependence of the conductivity indicates semiconducting behavior with an apparent room temperature activation energy of 0.11 eV. The highest room temperature conductivity observed was 30 S cm⁻1. Films 110 nm thick show 40% transparency in most of the visible spectrum and become much more transparent in the infrared spectrum. The p-type behavior was confirmed by the Seebeck effect

Iminohydantoin Lesion Induced in DNA by Peracids and Other Epoxidizing Oxidants

The oxidation of guanine to 5-carboxamido-5-formamido-2-iminohydantoin (2-Ih) is shown to be a major transformation in the oxidation of the single-stranded DNA 5-mer d(TTGTT) by m-CPBA and DMDO as a model for peracid oxidants and in the oxidation of the 5-base pair duplex d[(TTGTT)·(AACAA)] with DMDO. 2-Ih has not been reported as an oxidative lesion at the level of single/double-stranded DNA or at the nucleoside/nucleotide level. The lesion is stable to DNA digestion and chromatographic purification suggesting that 2-Ih may be a stable biomarker in vivo. The oxidation products have been structurally characterized and the reaction mechanism probed by oxidation of the monomeric species dGuo, dGMP and dGTP. DMDO selectively oxidizes the guanine moiety of dGuo, dGMP and dGTP to 2-Ih, and both peracetic and m-chloroperbenzoic acids exhibit the same selectivity. The presence of the glycosidic bond results in the stereoselective induction of an asymmetric center at the spiro carbon to give a mixture of diastereomers, with each diastereomer in equilibrium with a minor conformer through rotation about the formamido C-N bond. Labeling studies with 18O2-m-CPBA and H218O to determine the source of the added oxygen atoms have established initial epoxidation of the guanine 4-5 bond with pyrimidine ring contraction by an acyl 1,2-migration of guanine carbonyl C6 to form a transient dehydrodeoxyspiroiminodihydantoin followed by hydrolytic ring opening of the imidazolone ring. Consistent with the proposed mechanism, no 8-oxoguanine was detected as a product of the oxidations of the oligonucleotides or monomeric species mediated by DMDO or the peracids. The 2-Ih base thus appears to be a pathway-specific lesion generated by peracids and possibly other epoxidizing agents and holds promise as a potential biomarker