龙刘两库补水调度对黄河水环境补偿效益计算

为完善河流水库对下游环境补偿效益计算,文章首先给出水库水环境补偿效益内涵,其次,引入底标比和为排标比来改进现行污径比;在此基础上,提出利用新污径比量化计算水库对下游水环境补偿效益计算方法和步骤。最后,以黄河龙羊峡和刘家峡水库2003年调度为例,计算结果显示:2003年龙羊峡和刘家峡水库对兰州、头道怪、三门峡和花园口4站段的水环境补偿效益分别是0.784、0.888、0.099和0.140亿元及0.288、0.326、0.036和0.051亿元;2003年龙羊峡和刘家峡水库各自为下游创造总的水环境补偿效益分别为1.910和0.702亿元。文章旨在通过对黄河水环境补偿的定量分析,引起有关决策部门对河流水环境补偿问题的重视,达到抛砖引玉的目的。     

耳机被动降噪特性分析

在近似扩散场条件下,测试了入耳式和耳罩式耳机的被动降噪曲线,基于测试结果和线路图模型仿真,对影响耳机被动降噪特性的因素进行了探究和理论分析。结果表明无论是对与人耳紧密耦合的入耳式耳机,还是将人耳罩住的头戴耳机,耳套是影响耳机被动降噪能力的重要因素。     

酶解-交联法制备多孔淀粉及其负载红景天苷研究

以玉米淀粉为原料,采用α-淀粉酶和糖化酶复合酶解与三偏磷酸钠交联改性相结合的方法制备了一系列具有不同交联度的交联多孔淀粉。通过各种表征手段考察了原玉米淀粉、多孔淀粉和交联多孔淀粉的形态结构和理化性质,并应用于负载红景天苷研究。该方法制备的交联多孔淀粉具有良好的蜂窝状中空结构,有利于淀粉颗粒对目的物质的吸附。相比原淀粉和未交联多孔淀粉,交联多孔淀粉的吸油率有较大提高,对红景天苷的包封率为58.89%。经过交联反应后的交联多孔淀粉不但晶型没有发生改变,还具有更高的总孔面积、平均孔直径和孔隙率值,其分子结构也更加紧凑,更具刚性和更高的糊化温度,说明交联改性提高了多孔淀粉的结构性能。体外释放结果表明载药交联多孔淀粉具有一定的缓释性能,能够提高红景天苷的生物半衰期和生物利用度。      

油浸鲣鱼罐头贮藏过程中挥发性成分的变化规律研究

运用电子鼻和顶空固相微萃取气质联用（headspace solid phase micro extraction gas chromatograph-mass spectrometer,HS-SPME-GC-MS）技术,分析不同贮藏时间的油浸鲣鱼罐头的挥发性成分的变化。结果表明:电子鼻能够快速、灵敏地检测到油浸鲣鱼罐头在贮藏过程中的气味变化。利用气质联用仪在油浸鲣鱼罐头贮藏过程共鉴定出47种可挥发性化合物,呋喃类化合物、含氮类化合物为主要挥发性成分,其中呋喃类化合物相对含量随着贮藏时间的延长,含量不断降低,从刚出厂罐头的51.42%减少到贮藏第4年的41.20%。电子鼻可以用来区分罐头的贮藏时间,超过保质期的罐头挥发性风味物质变化较大。      

Incorporation of a FRET Pair into a Riboswitch RNA to Measure Mg2+ Concentration and RNA Conformational Change in Cell

Riboswitches are natural biosensors that can regulate gene expression by sensing small molecules. Knowledge of the structural dynamics of riboswitches is crucial to elucidate their regulatory mechanism and develop RNA biosensors. In this work, we incorporated the fluorophore, Cy3, and its quencher, TQ3, into a full-length adenine riboswitch RNA and its isolated aptamer domain to monitor the dynamics of the RNAs in vitro and in cell. The adenine riboswitch was sensitive to Mg²⁺ concentrations and could be used as a biosensor to measure cellular Mg²⁺ concentrations. Additionally, the TQ3/Cy3-labeled adenine riboswitch yielded a Mg²⁺ concentration that was similar to that measured using a commercial assay kit. Furthermore, the fluorescence response to the adenine of the TQ3/Cy3-labeled riboswitch RNA was applied to determine the proportions of multiple RNA conformational changes in cells. The strategy developed in this work can be used to probe the dynamics of other RNAs in cells and may facilitate the developments of RNA biosensors, drugs and engineering.     

In Vitro and In Vivo Modeling of Normal and Leukemic Bone Marrow Niches: Cellular Senescence Contribution to Leukemia Induction and Progression

Cellular senescence is recognized as a dynamic process in which cells evolve and adapt in a context dependent manner; consequently, senescent cells can exert both beneficial and deleterious effects on their surroundings. Specifically, senescent mesenchymal stromal cells (MSC) in the bone marrow (BM) have been linked to the generation of a supporting microenvironment that enhances malignant cell survival. However, the study of MSC’s senescence role in leukemia development has been straitened not only by the availability of suitable models that faithfully reflect the structural complexity and biological diversity of the events triggered in the BM, but also by the lack of a universal, standardized method to measure senescence. Despite these constraints, two- and three dimensional in vitro models have been continuously improved in terms of cell culture techniques, support materials and analysis methods; in addition, research on animal models tends to focus on the development of techniques that allow tracking leukemic and senescent cells in the living organism, as well as to modify the available mice strains to generate individuals that mimic human BM characteristics. Here, we present the main advances in leukemic niche modeling, discussing advantages and limitations of the different systems, focusing on the contribution of senescent MSC to leukemia progression.     

Identification of Spliceogenic Variants beyond Canonical GT-AG Splice Sites in Hereditary Cancer Genes

Pathogenic/likely pathogenic variants in susceptibility genes that interrupt RNA splicing are a well-documented mechanism of hereditary cancer syndromes development. However, if RNA studies are not performed, most of the variants beyond the canonical GT-AG splice site are characterized as variants of uncertain significance (VUS). To decrease the VUS burden, we have bioinformatically evaluated all novel VUS detected in 732 consecutive patients tested in the routine genetic counseling process. Twelve VUS that were predicted to cause splicing defects were selected for mRNA analysis. Here, we report a functional characterization of 12 variants located beyond the first two intronic nucleotides using RNAseq in APC, ATM, FH, LZTR1, MSH6, PALB2, RAD51C, and TP53 genes. Based on the analysis of mRNA, we have successfully reclassified 50% of investigated variants. 25% of variants were downgraded to likely benign, whereas 25% were upgraded to likely pathogenic leading to improved clinical management of the patient and the family members.     

阶梯式程序教学法在足球教学中的应用

踢球阶梯式程序教学法是指在踢球教学中按照踢球技术动作难度设定一定的程序,指导学生逐步提高踢球技术水平的教学方法。实践证明,踢球阶梯式程序教学法比传统踢球教学法有明显的成效。     

试论修水河源的确定

经过几年的考察分析,对修水河河源的确定做了一些论证工作,阐明修水的源河与发源地．     

AR参数灵敏度及结构损伤控制图识别

推导了时间序列模型的自回归参数对结构单元刚度损伤系数的灵敏度方程,并对该方程的正确性进行了验证。分析了自回归参数的灵敏度特性,在此基础上采用控制图进行结构损伤识别。该方法首先以结构在随机作用下的时域响应进行主成分分析;然后以第一主元建立适用阶的时序模型;最后以自回归参数建立休哈特控制图,通过自回归参数的统计性变化判断结构是否发生损伤。针对一梁结构,试验验证了控制图用于损伤识别的有效性和可行性。