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Murthy GS Johnston DB Rausch KD Tumbleson ME Singh V 《Bioprocess and biosystems engineering》2011,34(7):879-890
Efficiency of the starch hydrolysis in the dry grind corn process is a determining factor for overall conversion of starch
to ethanol. A model, based on a molecular approach, was developed to simulate structure and hydrolysis of starch. Starch structure
was modeled based on a cluster model of amylopectin. Enzymatic hydrolysis of amylose and amylopectin was modeled using a Monte
Carlo simulation method. The model included the effects of process variables such as temperature, pH, enzyme activity and
enzyme dose. Pure starches from wet milled waxy and high-amylose corn hybrids and ground yellow dent corn were hydrolyzed
to validate the model. Standard deviations in the model predictions for glucose concentration and DE values after saccharification
were less than ±0.15% (w/v) and ±0.35%, respectively. Correlation coefficients for model predictions and experimental values
were 0.60 and 0.91 for liquefaction and 0.84 and 0.71 for saccharification of amylose and amylopectin, respectively. Model
predictions for glucose (R
2 = 0.69–0.79) and DP4+ (R
2 = 0.8–0.68) were more accurate than the maltotriose and maltose for hydrolysis of high-amylose and waxy corn starch. For
yellow dent corn, simulation predictions for glucose were accurate (R
2 > 0.73) indicating that the model can be used to predict the glucose concentrations during starch hydrolysis. 相似文献
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Mir Abbas Bozorgirad Hao Zhang Karl R. Haapala Ganti S. Murthy 《The International Journal of Life Cycle Assessment》2013,18(8):1502-1512
Purpose
Municipal solid waste (MSW) can be handled with several traditional management strategies, including landfilling, incineration, and recycling. Ethanol production from MSW is a novel strategy that has been proposed and researched for practical use; however, MSW ethanol plants are not widely applied in practice. Thus, this study has been conducted to analyze and compare the environmental and economic performance of incineration and ethanol production as alternatives to landfilling MSW.Methods
The ISO 14040 life cycle assessment framework is employed to conduct the environmental impact assessment of three different scenarios for the two MSW management strategies based on processing 1 ton of MSW as the functional unit. The first scenario models the process of incinerating MSW and recovering energy in the form of process heat; the second scenario also includes the process of incinerating MSW but yields in the recovery of energy in the form of electricity; and the third scenario models the process of converting MSW into ethanol. The economic impacts of each scenario are then assessed by performing benefit-to-cost ratio (BCR) and net present value (NPV) analyses.Results and discussion
The results from the environmental impact assessment of each scenario reveal that scenario 2 has the highest benefits for resource availability while scenario 3 is shown to be the best alternative to avoid human health and ecosystems diversity impacts. Scenario 1 has the worst environmental performance with respect to each of these environmental endpoint indicators and has net environmental impacts. The results of the economic analysis indicate that the third scenario is the best option with respect to BCR and NPV, followed by scenarios 2 and 1, respectively. Furthermore, environmental and economic analysis results are shown to be sensitive to MSW composition.Conclusions
It appears municipalities should prefer MSW incineration with electricity generation or MSW-to-ethanol conversion over MSW incineration with heat recovery as an alternative to landfilling. The contradiction between the environmental impact assessment results and economic analysis results demonstrates that the decision-making process is sensitive to a broad set of variables. Decisions for a specific MSW management system are subject to facility location and size, MSW composition, energy prices, and governmental policies. 相似文献17.
Basu A Jain P Sarkar P Gangodkar S Deshpande D Ganti K Shetty S Ghosh K 《FEMS immunology and medical microbiology》2011,62(2):140-147
Dengue virus (DENV) infection of human endothelial cells has been implicated in the pathobiology of dengue hemorrhagic fever and dengue shock syndrome. However, the mechanisms by which DENV infections alter the functional physiology of endothelial cells remain incompletely understood. In the present study, we examined the susceptibility of a human liver sinusoidal endothelial cell line SK Hep1 to all four serotypes of DENV and studied the effect of the virus on in vitro angiogenesis. All four serotypes of DENV could infect the SK Hep1 cells, but showed variable cytopathic effects, the most pronounced being that of DENV-2. Electron microscopy of the infected cells showed significant ultrastructural changes. In vitro angiogenesis assays on DENV-2 exposed SK Hep1 cells in the matrigel system showed inhibition compared with the controls. Importantly, transfection and transient expression of the DENV-2 envelope glycoprotein (E) in these cells showed drastic alterations in cell shapes and the E protein could be localized by fluorescence microscopy in terminal knob-like structures. Therefore, SK Hep1, a human hepatic sinusoid-derived endothelial cell line, may constitute a potential model to study DENV-endothelial cell interactions in vitro, especially towards understanding the possible virus-induced changes in hepatic endothelium and its role in disease pathogenesis. 相似文献
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Julianna Han Ketaki Ganti Veeresh Kumar Sali Carly Twigg Yifeng Zhang Senthamizharasi Manivasagam Chieh-Yu Liang Olivia A. Vogel Iris Huang Shanan N. Emmanuel Jesse Plung Lillianna Radoshevich Jasmine T. Perez Anice C. Lowen Balaji Manicassamy 《PLoS pathogens》2021,17(5)
It is well documented that influenza A viruses selectively package 8 distinct viral ribonucleoprotein complexes (vRNPs) into each virion; however, the role of host factors in genome assembly is not completely understood. To evaluate the significance of cellular factors in genome assembly, we generated a reporter virus carrying a tetracysteine tag in the NP gene (NP-Tc virus) and assessed the dynamics of vRNP localization with cellular components by fluorescence microscopy. At early time points, vRNP complexes were preferentially exported to the MTOC; subsequently, vRNPs associated on vesicles positive for cellular factor Rab11a and formed distinct vRNP bundles that trafficked to the plasma membrane on microtubule networks. In Rab11a deficient cells, however, vRNP bundles were smaller in the cytoplasm with less co-localization between different vRNP segments. Furthermore, Rab11a deficiency increased the production of non-infectious particles with higher RNA copy number to PFU ratios, indicative of defects in specific genome assembly. These results indicate that Rab11a+ vesicles serve as hubs for the congregation of vRNP complexes and enable specific genome assembly through vRNP:vRNP interactions, revealing the importance of Rab11a as a critical host factor for influenza A virus genome assembly. 相似文献