Selective Breeding and Development of Disease Resistant Broodstock of Black Tiger Shrimp Penaeus monodon Fabricius, 1798

The Indian tiger shrimp Penaeus monodon is the principal species being cultured. Of late hatchery sector is being dependent on wild gravid females due to non response of broodstock to eyestalk ablation. High cost of gravid females compelling the grow-out sector to stock pathogen carrier seeds. Hence domestication of tiger shrimp is essential to produce Specific Pathogen Free (SPF) broodstock / Disease Resistant (DR) broodstock. Merits and demerits of SPF versus DR broodstock are presented. Development of SPF broodstock involves stringent management of environment to arrest the entry of pathogens and more than one economic trait can be selected. Whereas in development of DR broodstockanimals are challenged with the pathogen and a selection of other economic traits are less possible. Resistance in shrimp exists at the species level as well as individual level. Experiment on domestication of P. monodon in which programme was advanced up to F3 generation has revealed the existence of resistance for WSSV at the individual level. Selective breeding programme for development of D R broodstock involves development of disease free base population, forming them into families, production of F1 generation family wise through inbreeding, challenging each family with WSSV at 3-5 g size and rearing survived individuals up to 100 g size, production of F2 generation by random inter crossing between families, advancing the programme up to F5 generation. Development of DR broodstock is imperative to ensure sustainable shrimp productio

Effect of Testosterone Hormone on Performance of Male Broodstock of Black Tiger Shrimp Penaeus monodon Fabricius, 1798

In domestication and development of captive broodstock of tiger shrimp Penaeus monodon mating failures due to poor performance of male brood stock. To overcome this drawback the effect of the testosterone hormone on the performance of male broodstock was evaluated by injecting the hormone at the rate of 5 µg/g. body weight at

Plasma Polymerised Organic Thin Films-A Study on the Structural, Electrical and Nonlinear Optical Properties for Possible Applications

This proposed thesis is entitled “Plasma Polymerised Organic Thin Films: A study on the Structural, Electrical, and Nonlinear Optical Properties for Possible Applications. Polymers and polymer based materials find enormous applications in the realm of electronics and optoelectronics. They are employed as both active and passive components in making various devices. Enormous research activities are going on in this area for the last three decades or so, and many useful contributions are made quite accidentally. Conducting polymers is such a discovery, and eversince the discovery of conducting polyacetylene, a new branch of science itself has emerged in the form of synthetic metals. Conducting polymers are useful materials for many applications like polymer displays, high density data storage, polymer FETs, polymer LEDs, photo voltaic devices and electrochemical cells. With the emergence of molecular electronics and its potential in finding useful applications, organic thin films are receiving an unusual attention by scientists and engineers alike. This is evident from the vast literature pertaining to this field appearing in various journals. Recently, computer aided design of organic molecules have added further impetus to the ongoing research activities in this area. Polymers, especially, conducting polymers can be prepared both in the bulk and in the thinfilm form. However, many applications necessitate that they are grown in the thin film form either as free standing or on appropriate substrates. As far as their bulk counterparts are concerned, they can be prepared by various polymerisation techniques such as chemical routes and electrochemical means. A survey of the literature reveals that polymers like polyaniline, polypyrrole, polythiophene, have been investigated with a view to studying their structural electrical and optical properties. Among the various alternate techniques employed for the preparation of polymer thin films, the method of plasma polymerisation needs special attention in this context. The technique of plasma polymerisation is an inexpensive method and often requires very less infra structure. This method includes the employment of ac, rf, dc, microwave and pulsed sources. They produce pinhole free homogeneous films on appropriate substrates under controlled conditions. In conventional plasma polymerisation set up, the monomer is fed into an evacuated chamber and an ac/rf/dc/ w/pulsed discharge is created which enables the monomer species to dissociate, leading to the formation of polymer thin films. However, it has been found that the structure and hence the properties exhibited by plasma polymerized thin films are quite different from that of their counterparts produced by other thin film preparation techniques such as electrochemical deposition or spin coating. The properties of these thin films can be tuned only if the interrelationship between the structure and other properties are understood from a fundamental point of view. So very often, a through evaluation of the various properties is a pre-requisite for tailoring the properties of the thin films for applications. It has been found that conjugation is a necessary condition for enhancing the conductivity of polymer thin films. RF technique of plasma polymerisation is an excellent tool to induce conjugation and this modifies the electrical properties too. Both oxidative and reductive doping can be employed to modify the electrical properties of the polymer thin films for various applications. This is where organic thin films based on polymers scored over inorganic thin films, where in large area devices can be fabricated with organic semiconductors which is difficult to achieve by inorganic materials. For such applications, a variety of polymers have been synthesized such as polyaniline, polythiophene, polypyrrole etc. There are newer polymers added to this family every now and then. There are many virgin areas where plasma polymers are yet to make a foray namely low-k dielectrics or as potential nonlinear optical materials such as optical limiters. There are also many materials which are not been prepared by the method of plasma polymerisation. Some of the materials which are not been dealt with are phenyl hydrazine and tea tree oil. The advantage of employing organic extracts like tea tree oil monomers as precursors for making plasma polymers is that there can be value addition to the already existing uses and possibility exists in converting them to electronic grade materials, especially semiconductors and optically active materials for photonic applications. One of the major motivations of this study is to synthesize plasma polymer thin films based on aniline, phenyl hydrazine, pyrrole, tea tree oil and eucalyptus oil by employing both rf and ac plasma polymerisation techniques. This will be carried out with the objective of growing thin films on various substrates such as glass, quartz and indium tin oxide (ITO) coated glass. There are various properties namely structural, electrical, dielectric permittivity, nonlinear optical properties which are to be evaluated to establish the relationship with the structure and the other properties. Special emphasis will be laid in evaluating the optical parameters like refractive index (n), extinction coefficient (k), the real and imaginary components of dielectric constant and the optical transition energies of the polymer thin films from the spectroscopic ellipsometric studies. Apart from evaluating these physical constants, it is also possible to predict whether a material exhibit nonlinear optical properties by ellipsometric investigations. So further studies using open aperture z-scan technique in order to evaluate the nonlinear optical properties of a few selected samples which are potential nonlinear optical materials is another objective of the present study. It will be another endeavour to offer an appropriate explanation for the nonlinear optical properties displayed by these films. Doping of plasma polymers is found to modify both the electrical conductivity and optical properties. Iodine is found to modify the properties of the polymer thin films. However insitu iodine doping is tricky and the film often looses its stability because of the escape of iodine. An appropriate insitu technique of doping will be developed to dope iodine in to the plasma polymerized thin films. Doping of polymer thin films with iodine results in improved and modified optical and electrical properties. However it requires tools like FTIR and UV-Vis-NIR spectroscopy to elucidate the structural and optical modifications imparted to the polymer films. This will be attempted here to establish the role of iodine in the modification of the properties exhibited by the film

Large enhanced dielectric permittivity in polyaniline passivated core-shell nano magnetic iron oxide by plasma polymerization

Commercial samples of Magnetite with size ranging from 25–30nm were coated with polyaniline by using radio frequency plasma polymerization to achieve a core shell structure of magnetic nanoparticle (core)–Polyaniline (shell). High resolution transmission electron microscopy images confirm the core shell architecture of polyaniline coated iron oxide. The dielectric properties of the material were studied before and after plasma treatment. The polymer coated magnetite particles exhibited a large dielectric permittivity with respect to uncoated samples. The dielectric behavior was modeled using a Maxwell–Wagner capacitor model. A plausible mechanism for the enhancement of dielectric permittivity is propose

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Not AvailableThe Indian tiger shrimp Penaeus monodon is the principal species being cultured. Of late hatchery sector is being dependent on wild gravid females due to non response of broodstock to eyestalk ablation. High cost of gravid females compelling the grow-out sector to stock pathogen carrier seeds. Hence domestication of tiger shrimp is essential to produce Specific Pathogen Free (SPF) broodstock / Disease Resistant (DR) broodstock. Merits and demerits of SPF versus DR broodstock are presented. Development of SPF broodstock involves stringent management of environment to arrest the entry of pathogens and more than one economic trait can be selected. Whereas in development of DR broodstockanimals are challenged with the pathogen and a selection of other economic traits are less possible. Resistance in shrimp exists at the species level as well as individual level. Experiment on domestication of P. monodon in which programme was advanced up to F3 generation has revealed the existence of resistance for WSSV at the individual level. Selective breeding programme for development of D R broodstock involves development of disease free base population, forming them into families, production of F1 generation family wise through inbreeding, challenging each family with WSSV at 3-5 g size and rearing survived individuals up to 100 g size, production of F2 generation by random inter crossing between families, advancing the programme up to F5 generation. Development of DR broodstock is imperative to ensure sustainable shrimp productionNot Availabl

Contact potential induced enhancement of magnetization in polyaniline coated nanomagnetic iron oxides by plasma polymerization

The present work derives motivation from the so called surface/interfacial magnetism in core shell structures and commercial samples of Fe3O4 and c Fe2O3 with sizes ranging from 20 to 30 nm were coated with polyaniline using plasma polymerization and studied. The High Resolution Transmission Electron Microscopy images indicate a core shell structure after polyaniline coating and exhibited an increase in saturation magnetization by 2 emu/g. For confirmation, plasma polymerization was performed on maghemite nanoparticles which also exhibited an increase in saturation magnetization. This enhanced magnetization is rather surprising and the reason is found to be an interfacial phenomenon resulting from a contact potential.Cochin University of Science and TechnologyAppl. Phys. Lett. 103, 162414 (2013