8 resultados para Material culture

em Indian Institute of Science - Bangalore - Índia


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Cryogel matrices composed of different polymeric blends were synthesized, yielding a unique combination of hydrophilicity and hydrophobicity with the presence or absence of charged surface. Four such cryogel matrices composed of polyacrylamide-chitosan (PAAC), poly(N-isopropylacrylamide)-chitosan, polyacrylonitrile (PAN), and poly(N-isopropylacrylamide) were tested for growth of different hybridoma cell lines and production of antibody in static culture. All the matrices were capable for the adherence of hybridoma cell lines 6A4D7, B7B10, and H9E10 to the polymeric surfaces as well as for the efficient monoclonal antibody (mAb) production. PAAC proved to be relatively better in terms of both mAb production and cell growth. Further, PAAC cryogel was designed into three different formats, monolith, disks, and beads, and used as packing material for packed-bed bioreactor. Longterm cultivation of 6A4D7 cell line on PAAC cryogel scaffold in all the three formats could be successfully done for a period of 6 weeks under static conditions. Continuous packed-bed bioreactor was setup using 6A4D7 hybridoma cell line in the three reactor formats. The reactors ran continuously for a period of 60 days during which mAb production and metabolism of cells in the bioreactors were monitored periodically. The monolith bioreactor performed most efficiently over a period of 60 days and produced a total of 57.5 mg of antibody in the first 30 days (in 500 mL) with a highest concentration of 115 mu g mL(-1), which is fourfold higher than t-flask culture. The results demonstrate that appropriate chemistry and geometry of the bioreactor matrix for cell growth and immobilization can enhance the reactor productivity. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 27: 170-180, 2011

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The quest for prosperity has been a central motive in the life of man from the moment of his entrance into the worldly scence. And certain, it is that the issue of prosperity at the very cost of his very existence has mounted in intensity and urgency with the unforeseen evolution of industrialization. The traditional paradigm of prosperity has been resting on the classical theory of production economics.With increasing empiricism it is obvious that the rational model fail to grapple with the complexity of the concept. The paper addresses the prosperity as an goal state resting on the conviction of harmony between present generation and generation of humans to come. Sustainable prosperity involves more than growth in services/goods. It requires a change in the content of the growth, to make it less material-and energy-intensive and more equitable in its impact. The process of economic prosperity must be more soundly based upon the realities of the stock of capital that sustains it.

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A complex oxalate precursor, CaCu3(TiO)(4)(C2O4)(8)center dot 9H(2)O, (CCT-OX), was synthesized and the precipitate that obtained was confirmed to be monophasic by the wet chemical analyses, X-ray diffraction, FTIR absorption and TG/DTA analyses. The thermal decomposition of this oxalate precursor led to the formation of phase-pure calcium copper titanate, CaCu3Ti4O12, (CCTO) at a parts per thousand yen680A degrees C. The bright-field TEM micrographs revealed that the size of the as synthesized crystallites to be in the 30-80 nm range. The powders so obtained had excellent sinterability resulting in high density ceramics which exhibited giant dielectric constants upto 40000 (1 kHz) at 25A degrees C, accompanied by low dielectric losses.

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Electrochemical capacity retention of nearly X-ray amorphous nanostructured manganese oxide (nanoMnO2) synthesized by mixing directly KMnO4 with ethylene glycol under ambient conditions for supercapacitor studies is enhanced significantly. Although X-ray diffraction (XRD) pattern of nanoMnO2 shows poor crystallinity, it is found that by Mn K-edge X-ray absorption near edge structure (XANES) measurement that the nanoMnO2 obtained is locally arranged in a δ-MnO2-type layered structure composed of edge-shared network of MnO6 octahedra. Field emission scanning electron microscopy and XANES measurements show that nanoMnO2 contains nearly spherical shaped morphology with δ-MnO2 structure, and 1D nanorods of α-MnO2 type structure (powder XRD) in the annealed (600 °C) sample. Volumetric nitrogen adsorption−desorption isotherms, inductively coupled plasma analysis, and thermal analysis are carried out to obtain physicochemical properties such as surface area (230 m2 g−1), porosity of nanoMnO2 (secondary mesopores of diameter 14.5 nm), water content, composition, etc., which lead to the promising electrochemical properties as an electrode for supercapacitor. The nanoMnO2 shows a very high stability even after 1200 cycles with capacity retention of about 250 F g−1.

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Axillary shoot proliferation was obtained using explants of Eucalyptus grandis L. juvenile and mature stages on a defined medium. Murashige and Skoog medium (MS) supplemented with benzyladenine (BA), naphthalene acetic acid (NAA) and additional thiamine. Excised shoots were induced to root on a sequence of three media: (1) White's medium containing indoleacetic acid (IAA), NAA and indole butyric acid; (IBA), (2) half-strength MS medium with charcoal and (3) half-strength MS liquid medium. The two types of explants differed in rooting response, with juvenile-derived shoots giving 60% rooting and adult-derived ones only 35%. Thus, the factors limiting cloning of selected trees in vitro are determined to be those controlling rooting of shoots in E. grandis.

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The role of melt convection oil the performance of beat sinks with Phase Change Material (PCM) is presented in this paper. The beat sink consists of aluminum plate fins embedded in PCM and heat flux is supplied from the bottom. The design of such a heat sink requires optimization with respect to its geometrical parameters. The objective of the optimization is to maximize the heat sink operation time for the prescribed heat flux and the critical chip temperature. The parameters considered for optimization are fin number and fill thickness. The height and base plate thickness of heat sink are kept constant in the present analysis. An enthalpy based CFD model is developed, which is capable Of Simulating phase change and associated melt convection. The CFD model is Coupled with Genetic Algorithm (GA) for carrying out the optimization. Two cases are considered, one without melt convection (conduction regime) and the other with convection. It is found that the geometrical optimizations of heat sinks are different for the two cases, indicating the importance of inch convection in the design of heat sinks with PCMs.

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A new method of modeling material behavior which accounts for the dynamic metallurgical processes occurring during hot deformation is presented. The approach in this method is to consider the workpiece as a dissipator of power in the total processing system and to evaluate the dissipated power co-contentJ = ∫o σ ε ⋅dσ from the constitutive equation relating the strain rate (ε) to the flow stress (σ). The optimum processing conditions of temperature and strain rate are those corresponding to the maximum or peak inJ. It is shown thatJ is related to the strain-rate sensitivity (m) of the material and reaches a maximum value(J max) whenm = 1. The efficiency of the power dissipation(J/J max) through metallurgical processes is shown to be an index of the dynamic behavior of the material and is useful in obtaining a unique combination of temperature and strain rate for processing and also in delineating the regions of internal fracture. In this method of modeling, noa priori knowledge or evaluation of the atomistic mechanisms is required, and the method is effective even when more than one dissipation process occurs, which is particularly advantageous in the hot processing of commercial alloys having complex microstructures. This method has been applied to modeling of the behavior of Ti-6242 during hot forging. The behavior of α+ β andβ preform microstructures has been exam-ined, and the results show that the optimum condition for hot forging of these preforms is obtained at 927 °C (1200 K) and a strain rate of 1CT•3 s•1. Variations in the efficiency of dissipation with temperature and strain rate are correlated with the dynamic microstructural changes occurring in the material.

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Multiple shoots were induced from nodal segments of five year old trees of Eucalyptus grandis L. on solid medium containing Murashige and Skoog's (MS) Basal medium supplemented with additional thiamine, BAP and NAA. Rooting could be achieved from shoot culture on half strength MS salts or white's medium supplemented with low auxins like IAA, IBA and NAA.