胃肠道调理专用奶粉对便秘小鼠肠道动力和菌群组成的影响

目的:研究胃肠道调理专用奶粉润肠通便作用及对肠道菌群的影响。方法:自制胃肠道调理专用奶粉后,以KM小鼠为实验对象,采用盐酸咯哌丁胺建立小鼠便秘模型,以小鼠一般状态、小肠推进率、排便情况、小肠组织观察为考察指标结合16S rRNA基因测序分析小鼠粪便,考察其对小鼠的润肠通便作用及肠道菌群的影响。结果:胃肠道调理专用奶粉各剂量能够显著（P<0.05）缩短小鼠首粒排便时间、显著（P<0.05）提高小鼠小肠推进率,但未对小鼠小肠杯状细胞结构造成破坏,且随着剂量的提升,奶粉的胃肠调理效果越好。胃肠道调理专用奶粉虽然没有明显改变肠道微生物的丰富度和均匀度,但是能够明显改变小鼠的肠道微生态结构组成,显著（P<0.05）增加某些益生菌Lactobacillus、Bifidobacterium的相对丰度。结论:胃肠道调理专用奶粉能够影响肠道运动,调节肠道菌群结构从而改善洛哌丁胺引起的便秘。     

Comparative Molecular Dynamics Simulations of Mitogen-Activated Protein Kinase-Activated Protein Kinase 5

The mitogen-activated protein kinase-activated protein kinase MK5 is a substrate of the mitogen-activated protein kinases p38, ERK3 and ERK4. Cell culture and animal studies have demonstrated that MK5 is involved in tumour suppression and promotion, embryogenesis, anxiety, cell motility and cell cycle regulation. In the present study, homology models of MK5 were used for molecular dynamics (MD) simulations of: (1) MK5 alone; (2) MK5 in complex with an inhibitor; and (3) MK5 in complex with the interaction partner p38α. The calculations showed that the inhibitor occupied the active site and disrupted the intramolecular network of amino acids. However, intramolecular interactions consistent with an inactive protein kinase fold were not formed. MD with p38α showed that not only the p38 docking region, but also amino acids in the activation segment, αH helix, P-loop, regulatory phosphorylation region and the C-terminal of MK5 may be involved in forming a very stable MK5-p38α complex, and that p38α binding decreases the residual fluctuation of the MK5 model. Electrostatic Potential Surface (EPS) calculations of MK5 and p38α showed that electrostatic interactions are important for recognition and binding.     

动态潮汐能大坝影响因素及坝型数值研究

动态潮汐能是一种新型的潮汐能,它利用开敞式的大坝阻断潮波的行进,在其两侧形成一定的水头差,从而产生潜在的可再生潮汐能。文章利用MIKE21水动力模块对动态潮汐能的工作方式及其影响因素进行了数值模拟研究,在概化的海峡内布置不同尺寸和类型的大坝,利用数学模型计算了不同大坝长度、海域水深、近岸坡度和潮波振幅等对动态潮汐能的影响;模拟比较了T型与Y型DTP坝可产生的最大水头差。研究表明:DTP坝两侧的最大水头差与坝干尺寸、水深-1/2次幂,及潮波振幅成正比关系;海床坡度的增加有助于增大DTP两侧的水头差;在相同水深和潮波条件下,45°的Y型坝可产生较大的发电水头。     

浅析新疆水库溃坝模式及溃坝概率

根据资料对新疆已发生溃坝的水库进行了溃坝原因和溃坝概率统计分析,并结合水库溃坝实例总结了主要的溃坝原因,最后提出了合理运用工程措施和非工程措施来降低水库溃坝风险的对策。