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101.
102.
企业的发展需要资金的支持,资本结构的问题是企业进行融资决策时的一个重要问题。因为资本结构会影响企业的融资成本和市场价值,也会影响企业的治理结构,同时,资本结构通过企业行为和资本市场的运行也会影响总体经济的增长。通过分析企业进行融资的各种方式,并运用马科维茨的组合理论来合理确定负债比率。 相似文献
103.
Jianheng Liu Tao Huang Yusen Zhang Tianxuan Zhao Xueni Zhao Wanying Chen Rui Zhang 《国家科学评论(英文版)》2021,8(6):130-141
mRNA m5C, which has recently been implicated in the regulation of mRNA mobility, metabolism and translation, plays important regulatory roles in various biological events. Two types of m5C sites are found in mRNAs. Type I m5C sites, which contain a downstream G-rich triplet motif and are computationally predicted to be located at the 5′ end of putative hairpin structures, are methylated by NSUN2. Type II m5C sites contain a downstream UCCA motif and are computationally predicted to be located in the loops of putative hairpin structures. However, their biogenesis remains unknown. Here we identified NSUN6, a methyltransferase that is known to methylate C72 of tRNAThr and tRNACys, as an mRNA methyltransferase that targets Type II m5C sites. Combining the RNA secondary structure prediction, miCLIP, and results from a high-throughput mutagenesis analysis, we determined the RNA sequence and structural features governing the specificity of NSUN6-mediated mRNA methylation. Integrating these features into an NSUN6-RNA structural model, we identified an NSUN6 variant that largely loses tRNA methylation but retains mRNA methylation ability. Finally, we revealed a weak negative correlation between m5C methylation and translation efficiency. Our findings uncover that mRNA m5C is tightly controlled by an elaborate two-enzyme system, and the protein-RNA structure analysis strategy established may be applied to other RNA modification writers to distinguish the functions of different RNA substrates of a writer protein. 相似文献
104.
BackgroundPlanctomycetes is a phylum of biofilm-forming bacteria with numerous biosynthetic gene clusters, offering a promising source of new bioactive secondary metabolites. However, the current generation of chemically defined media achieves only low biomass yields, hindering research on these species. We therefore developed a chemically defined medium for the model organism Planctopirus limnophila to increase biomass production.ResultsWe found that P. limnophila grows best with a 10 mM sodium phosphate buffer. The replacement of complex nitrogen sources with defined amino acid solutions did not inhibit growth. Screening for vitamin requirements revealed that only cyanocobalamin (B12) is needed for growth. We used response surface methodology to optimize the medium, resulting in concentrations of 10 g/L glucose, 34 mL/L Hutner’s basal salts, 23.18 mM KNO3, 2.318 mM NH4Cl and 0.02 mg/L cyanocobalamin. The analysis of amino acid consumption allowed us to develop a customized amino acid solution lacking six of the amino acids present in Aminoplasmal 10%. Fed-batch cultivation in a bioreactor using the optimized medium achieved a final ΔOD600 of 46.8 ± 0.5 after 108 h, corresponding to a cell dry weight of 13.6 ± 0.7 g/L.ConclusionsThe optimized chemically defined medium allowed us to produce larger amounts of biomass more quickly than reported in earlier studies. Further research should focus on triggering P. limnophila biofilm formation to activate the gene clusters responsible for secondary metabolism.How to cite: Kruppa OC, Gerlach D, Fan R, et al. Development of a chemically defined medium for Planctopirus limnophila to increase biomass production. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.09.002. 相似文献
105.
通过对近十年我国体育教师专业能力的文献收集,将其分为中小学和大学两大类,并对每类文献做结构、现状、策略的综述。研究方法为文献资料法,逻辑分析法。研究结果:学者对体育教师专业能力结构的见解具有交叉性,但缺少统一的认识,研究范围较小,不足以代表合格教师所应具备的专业能力;现状和策略的研究较为陈旧,对提出的策略没有进一步跟进,策略缺乏创新,需要更深层次的研究。 相似文献
106.
袁君煊 《渭南师范学院学报》2014,(1):48-51
《四时田园杂兴》是范成大退居石湖创作的一组诗歌,自问世以来颇受瞩目,但至今仍少有人关注其特殊的结构形式。作者选择这一特殊结构形式有其特殊的寓意:纪念伴随其出生以来历久弥深的国耻。这一选择的驱动力来自我国的文化传统、作者的经历及对诗歌风格的好尚。 相似文献
107.
王艳华 《桂林师范高等专科学校学报》2011,25(2):107-110
首先从情绪工作的定义、特征出发分析教师是属于高情绪工作者,之后阐述情绪工作的调节策略以及影响调节策略的相关因素,以期为研究教师职业提供一个新视角。 相似文献
108.
金震海 《楚雄师范学院学报》2011,26(2):30-33,102
新罗时期的国语诗歌又称之为乡歌,它是朝鲜半岛最古老的国语诗歌。乡歌作品共有25首,其中《三国遗事》所载14首,《均如传》所载11首。通过对新罗乡歌作品结构的分析,可以进一步了解新罗国语诗歌的构成形式。《三国遗事》所载14首乡歌作品因其类型的多样性和记录方法的特殊性,在结构层面上也表现出了独特的一面。 相似文献
109.
Jennifer Ward Stephanie Branson Megan D. Cross Ilene R. Berson 《Journal of Research on Technology in Education》2016,48(3):227-238
This study explored how developmentally appropriate practices influenced the affordances of a multitouch surface in an early childhood classroom. Children, ages 4 to 5 years old, were videotaped while engaged in a storymaking application on a multitouch table. As a result of the study, we found that some challenges with the functionality undermined children's autonomous control. The researchers observed numerous instances of issues with control of the medium, including height of the table, sensitivity to multiple types of touch, and limited instructions and prompts. Implications for future research and practice are discussed. 相似文献
110.
David Andrich 《Educational Measurement》2016,35(4):25-30
Since Cronbach's (1951) elaboration of α from its introduction by Guttman (1945), this coefficient has become ubiquitous in characterizing assessment instruments in education, psychology, and other social sciences. Also ubiquitous are caveats on the calculation and interpretation of this coefficient. This article summarizes a recent contribution (Andrich, 2015) on the use of coefficient α which complements these many caveats. It shows that in the presence of a simple bifactor structure of a scale where unique components of variance are homogeneous in magnitude, three components of variance and the common latent common correlation among the subscales can be calculated from the ratio of two calculations of α, one at the level of the items, the other at the level of the subscales. It was suggested that these two ready calculations and their interpretation, and the reporting of all four indices in the analysis of scales with a subscale structure, would reduce the misinterpretation of this coefficient. An illustrative example of the application of the calculations is also shown. 相似文献