Browsing by Author "Mishra, Vijay Kumar"

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    Establishment of in Vitro Hapliids of Tea (Camellia SPP) and Their Potential for the Production of Secondary Metabolites
    (2013) Mishra, Vijay Kumar
    The tea plant is a tropical, evergreen plant of the family Theaceae and genus Camellia. It is one of the most economically important beverage crops in the world. Chinese were the first to use tea as medicinal drink, later as beverage and have been doing so far for more than 3000 years. The original home or primary centre of origin of tea was South-East Asia. The cultivated taxa of tea comprise three main types, which are mainly differentiated on the basis of their leaf size. Assam type has the biggest leaf size while China type has the smallest. The Cambod type has leaf in between Assam and China types. Tea plant is a highly cross pollinated and genetically complex species. The genus Camellia includes more than 325 species which indicates genetic instability and high out-breeding nature of the genus. There are 600 cultivated varieties worldwide with unique traits, such as high caffeine content, drought tolerance, blister blight disease tolerant etc. In spite of having valued properties, improvement of tea by conventional methods is very laborious and time consuming and owing to its highly heterozygous nature and long reproductive cycle. In this context, it is noteworthy that, studies utilizing gametophytic cells are in infancy, in this tree species. In vitro haploid production from gametophytic cells enables the establishment of completely homozygous lines in a shortened time frame compared to conventional methods and has many potential applications in plant improvement to establish inbred lines rapidly and to observe recessive traits. Therefore, the aim of the present study was to establish in vitro androgenic lines of tea from anthers. Androgenic haploids were produced by anthers, cultured at early-to-late uninucleate stage of pollen. Haploid development occurred via callusing of microspores. TV21 and TV19 cultivars were regenerated and developed to haploid plants. Further, the androgenic lines were checked for the production of medicinally important compounds, such as (+)-Catechin, (-)-Epicatechin, (-)-Epigallocatechin gallate, Caffeine and Theophylline. These compounds are observed to be present in maximum amount in young leaves of parent plants, followed by in vitro embryos and the least in calli. The presence of compounds has been confirmed by chromatographic and spectroscopic techniques. Antioxidant activity assays of in vitro androgenic cultures were also investigated and found that hot water extract (80जC for 20 min.) shows maximum activity. Batch kinetics.
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    Estimation of parameters in conduction-radiation heat transfer in Porous media
    (2016) Mishra, Vijay Kumar
    Development of thermal systems like a porous radiant burner, heat exchangers, insulations, etc., quantitative knowledge of heat and/or mass transfer, temperature field are essential. With geometric details, thermo-physical and optical properties, and initial and boundary conditions known, the desired results, viz., temperature and heat flux distributions are known by numerically solving a set of governing equations. However, when a thermal system is designed, a priori knowledge of some or all of the geometric parameters, and thermos-physical and optical properties of the material, and even initial and/or boundary conditions may not be known. Experimental route to optimize these parameters with trial and error approach for the desired outcome is not scientific. Recourse of an inverse analysis is the most preferred option by the scientific community. With thermo-physical properties and initial and boundary conditions known, calculations of the desired velocity field, temperature field or heat and mass flow rates, come under solving a direct problem. However, when either of the desired quantities (temperature, velocity fields, heat and mass transfer rates), and one or more of the properties or initial or boundary conditions are unknown, problem becomes an inverse one. In the direct problem, causes are known, and getting the outcomes are straightforward. On the contrary, in inverse problems, the outcome is known, but not the cause(s). Estimation of cause(s) is relatively, a difficult task. Mathematically, inverse problems are ill-posed. With even a slight variations in governing parameters, solution goes astray.