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The effect of growth phase on enzymatic activities of the de novo and salvage pathways for purine and pyrimidine nucleotide synthesis was studied in a hepatocyte-derived cell line from the rat. The cells were in lag phase after plating for 36 h; log phase started at 48 h and persisted up to 120 h of culture. Then the cells stopped growing and entered into plateau phase (144 h). In non-proliferating cells (144 h of culture) the basal activities of the enzymes of purine de novo biosynthesis were 1.7- to 6.8-fold higher than in normal rat liver, those of pyrimidine de novo synthesis showed 0.6- to 30-fold increase in activity. The purine salvage enzymes were unchanged, and the pyrimidine salvage enzymes were 3.1- to 7.4-fold higher compared to normal liver. During the growth cycle all enzymes except the purine salvage enzymes, which did not change, showed a peak in activity at 72 h of culture (log phase). The increase in activity in log phase compared to plateau phase was 1.3- to 2.4-fold for purine de novo synthetic enzymes, 1.1- to 2.4-fold for pyrimidine de novo enzymes, and 1.4- to 4.7-fold for pyrimidine salvage enzymes. The specific activities of the enzymes in exponentially growing cells were comparable either to that in 24-h regenerating liver, or to that in hepatomas of low or medium growth rate. It was concluded that the enzymatic pattern and metabolic state of the cells shared some features with regenerating liver, others with tumors, although they were not tumorigenic after transplantation into athymic nude mice.

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Current homogeneous catalysts used for commercial biodiesel synthesis are toxic and flammable. For Feedstock, their reaction requires refined oil which is a human food and expensive. In addition, due to contamination, the main byproduct of their reaction, glycerol is not usable for sale as a high value product and is land filled or burned as waste. Furthermore, the use of these catalysts in conversion of low cost feed-stocks such as waste oil and greases is not economical because their reactions produce soaps and clean up of the soap imposes additional processing cost to the biodiesel synthesis process. On the other hand, heterogeneous catalysts under development for biodiesel synthesis are either derived from non-renewable resources, or have problems with toxicity or stability. The solid heterogeneous bio-based catalysts are based on renewable resources, non-toxic, stable, effective, and low cost and are expected to work well for conversion of low cost feed-stocks such as waste oil and grease such as yellow, brown and black grease. In addition to catalyzing biodiesel synthesis, biobased catalysts can convert cellulosic agricultural waste to biofuel via saccarification followed by fermentation. Due to the abundance of cellulosic biomass in the nature, this reaction has great significance as it will affect the availability of not only biofuel from the fermentation of glucose, but also the availability of all organic chemicals and even hydrogen fuel from biomass. Because the catalytic active site in these catalysts are chemically bound, in contrast to other similar catalysts such as naphthalene sulfonic acid, the catalytic active sites of biobased catalysts will not break down, or leach. As a result, both the biodiesel and the glycerol by product will be free of catalyst contaminants. This allows the biodiesel to be safely burned and the glycerol byproduct to be sold as value-added commodity for pharmaceutical and cosmetic uses.

This paper describes the development of new biobased Polyurethanes (PU) starting from swine manure bio-resin and diisocyanates. The bio-resin is produced from swine manure via a hydrothermal process. For sustainability, today, many PUs in new specialized applications, are biobased. In this study, different commercial diisocyanates including MDI, Desmodur W, Desmodur H and Demodur I and swine manure, which is an agricultural waste were used to make the biobased PUs. The reactions were performed at refluxing THF, or in neat form at temperatures that ranged from room temperature to 100°C. Dibutyltin dilaurate was used as catalyst for the polymerization. Composites were characterized by FTIR, GPC, ICP and Rheometry. GPC confirmed the increase in the size of the molecules consistent with the increase in the viscosity and complex modulus of the reaction mixtures as a function of reaction time. One composite reached to elastic modulus of 10 MP at the end of the reaction process, which was marked by depletion of isocyanates peak in the IR. Progress of the polymerization reaction was monitored by the disappearance of the isocyanate band in the IR at ~2274 cm −1. By monitoring the FTIR spectra of the reaction mixtures while increasing MDI dosage in a step-wise manner, the number of the molar equivalents of the functional groups active towards isocyanate (including OH, H 2 S, NH 2 and COOH) in the bioresin was also determined.

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Black and Brown communities are affected disproportionately by COVID-19. In an attempt to learn if young Black college students unknowingly contribute to the spread of the COVID-19 in their communities, using surveys, this pilot study gauges the general safety knowledge and basic scientific knowledge of Black college students about SARS-COV-2 virus and COVID-19 at an HBCU. We also investigated whether students enrolled in chemistry courses designed for STEM (Science, Technology, and Engineering Majors) majors displayed increased knowledge of SARS-COV-2 and COVID-19 in comparison to their non-STEM major peers. Two sets of surveys with multiple choice questions, one with 25 and the other with 34 questions, were designed to assess general safety knowledge and basic scientific knowledge of the students about COVID-19 and the SARS-COV-2 virus. Survey questions were administered through Blackboard learning management system to one hundred eighty-seven (187) students in the summer of 2020 to two freshman non-science majors and in the fall of 2020 to one freshman non-science-major class, two freshmen STEM-major classes, and one senior STEM-major class. All students self-registered in the 6 chemistry classes at North Carolina A&T State University at random with no predetermined criteria. Results of the study show that regardless of their year of study, majority (> 90%) of the students possess basic scientific knowledge and are aware of the safety precautions concerning SARS-COV-2 virus and COVID-19. Majority of non-science major freshmen answered the basic safety questions correctly but were not able to choose the correct answers for the more specific scientific questions concerning SARS-COV-2 and COVID-19. Surprisingly, there was no significant difference in basic scientific knowledge regarding SARS-COV-2 and COVID-19 between STEM and non-STEM student populations, and first year STEM students were just as knowledgeable as senior STEM students. Based on these data, we speculate that students surveyed here have an acceptable basic understanding of how SARS-CoV-2 is transmitted, and therefore, they may not be a source of COVID-19 transmission to Black and Brown communities as this study confirms they are receiving accurate information about SARS-COV-2 and COVID-19. Possession of crucial timely and accurate knowledge about the health and safety is important in fighting racism and to gain equity within the society at large. By sharing the acquired knowledge, students can serve as positive role models for others in the community thus encouraging them to pursue science. Education brings equity, sharing the acquired knowledge encourages others to continue their education and succeed in obtaining higher degrees and better jobs as remedies for social inequality. Spread of accurate knowledge on various aspects of COVID-19 will also help remove fears of vaccination and hesitation towards visits to health clinics to resolve health issues. Relying on the results of this pilot study, we plan to explore these important factors fur...