Stem cell engineering of the endoderm: approaches to controlling endoderm induction and differentiation from embryonic stem cells

Embryonic stem (ES) cell technology holds promise for curing innumerable human ailments. However, studies of the endoderm germ layer and its derivatives (liver, pancreas, and lung) are lacking. The overall objective of this thesis is to elucidate the factors that influence endoderm induction and differentiation from ES cells. To improve results in aggregate culture, a microfabricated PDMS (polydimethylsiloxane) stencil was engineered using standard soft lithography techniques used to control ES cells. Precise control over initial aggregate size was obtained, varying the initial aggregate size from 100-500 µm. Analysis of the cells by RT-PCR (Reverse Transcriptase Polymerase Chain Reaction) demonstrated endoderm on Day 10 and hepatocyte-like cells on Day 20, but a mixed population was present. To further enhance endoderm induction, a coculture system was developed. The culture of ES cells on top of collagen-sandwiched mature rat hepatocytes, resulted in a rapid proliferation into a 95% positive endoderm progenitor population by Day 10. Late stage differentiation of these cells and placement in a extracorporeal device to support liver failure in rats resulted in enhanced (50%) survival. To further understand endoderm induction, a simpler culture system was developed. The culture of ES cells on fibronectin-coated collagen gels resulted in an endoderm fraction of 53% by Day 10 that remained committed upon in vivo implantation. Treatment with activin, an important TGFβ superfamily soluble factor, caused an 80% decrease in the endoderm fraction, while follistatin, an activin inhibitor with unknown function, increased the endoderm fraction to 78%. The activin treated population delayed the induction of endoderm by preventing differentiation of its transient precursors, the epiblast and mesendoderm. Differentiation of activin treated cells to Day 24 resulted in a two-fold reduction in hepatic gene expression and three-fold reduction in hepatic protein expression of when compared to follistatin-treated cells. Subcutaneous transplantation of activin-treated cells resulted in generated a heterogeneous teratoma-like mass, suggesting these cells were primitive. In summary, factors that influence endoderm induction include initial size of aggregate, coculture environment, extracellular matrix, and soluble factors. Two new tools for evaluating clinical applications include in vivo implantation and placement in an extracorporeal device.Ph.D.Includes bibliographical references

Bioengineering considerations in liver regenerative medicine

Abstract Background Liver disease contributes significantly to global disease burden and is associated with rising incidence and escalating costs. It is likely that innovative approaches, arising from the emerging field of liver regenerative medicine, will counter these trends. Main body Liver regenerative medicine is a rapidly expanding field based on a rich history of basic investigations into the nature of liver structure, physiology, development, regeneration, and function. With a bioengineering perspective, we discuss all major subfields within liver regenerative medicine, focusing on the history, seminal publications, recent progress within these fields, and commercialization efforts. The areas reviewed include fundamental aspects of liver transplantation, liver regeneration, primary hepatocyte cell culture, bioartificial liver, hepatocyte transplantation and liver cell therapies, mouse liver repopulation, adult liver stem cell/progenitor cells, pluripotent stem cells, hepatic microdevices, and decellularized liver grafts. Conclusion These studies highlight the creative directions of liver regenerative medicine, the collective efforts of scientists, engineers, and doctors, and the bright outlook for a wide range of approaches and applications which will impact patients with liver disease

Enumeration of pteridophytes in Banajalaya conserved forest area of Shimoga District, Karnataka

Nineteen species of pteridophytes belongs to 11 families were authentically documented in Banajalaya region in Sagar taluk of Shimoga district. Pteridaceae was occurred as the dominant family in study area. The majority of the ferns are terrestrial, two of them are epiphytic, and one is hydrophytic species. Present study helpful for conservation programmes of these ferns, which are important for their academic, medicinal and ornamental values

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Not Available-Krishi Vigyan Kendr

Experimental Study of a New Hydrocarbon Mixture for Domestic Re-frigerator to Replace R134a

In a domestic refrigerator with 4.49cc displacement compressors, the performance of R290 (48 by mass percent) and R600a (52 by mass percent) was examined experimentally. In our research, we employed a 210-litre refrigerator designed to run on R12 with a longer capillary. The amount of energy utilized and the pressure and temperature at crucial locations on the various refrigerated compartments and refrigerator circuits are all monitored. With R290/R600a, we performed a scroll-down test and ice-making test. According to our findings, R290/R600a are the best contenders for replacing R134a in terms of energy conservation. Because the amount of refrigerant utilized is so small, the flammability factor can be overlooked

An integer programming formulation to identify the sparse network architecture governing differentiation of embryonic stem cells

Motivation: Primary purpose of modeling gene regulatory networks for developmental process is to reveal pathways governing the cellular differentiation to specific phenotypes. Knowledge of differentiation network will enable generation of desired cell fates by careful alteration of the governing network by adequate manipulation of cellular environment

Hydrocarbons as alternative refrigerants in domestic refrigerators

The thermodynamic and volumetric properties of hydrocarbons namely Propane, Cyclopropane, Propene, Methyl acetylene, Propadiene and Dimethyl ether as replacements to substitute R134a have been assessed by means of SRK equation of state. The pressure magnitude, enthalpy, entropy, and specific capacity at the vapor and fluid phase have been analyzed over the temperature range from -250C to +55 0C. Ten state point vapor compression cycle is used to carry out the thermodynamic investigation of 89W local refrigerator. The theoretical enactment of the hydrocarbons has been comparatively assessed using standard refrigeration parameters such as displacement volume, volumetric efficiency, starting torque, refrigerating effect, discharge temperature, COP and rating of the motor. According to our results, Propane and Propene are appropriate and recommended as alternatives of R134a with lower displacement compressor and Cyclopropane as a direct substitute. Also implications with respect to material and lubricant oil compatibility, heat transfer characteristics are discussed