Disrupting the wall accumulation of human sperm cells by artificial corrugation

Many self-propelled microorganisms are attracted to surfaces. This makes their dynamics in restricted geometries very different from that observed in the bulk. Swimming along walls is beneficial for directing and sorting cells, but may be detrimental if homogeneous populations are desired, such as in counting microchambers. In this work, we characterize the motion of human sperm cells ∼60 μm long, strongly confined to ∼25 μm shallow chambers. We investigate the nature of the cell trajectories between the confining surfaces and their accumulation near the borders. Observed cell trajectories are composed of a succession of quasi-circular and quasi-linear segments. This suggests that the cells follow a path of intermittent trappings near the top and bottom surfaces separated by stretches of quasi-free motion in between the two surfaces, as confirmed by depth resolved confocal microscopy studies. We show that the introduction of artificial petal-shaped corrugation in the lateral boundaries removes the tendency of cells to accumulate near the borders, an effect which we hypothesize may be valuable for microfluidic applications in biomedicine.     

Core-shell hydrogel beads with extracellular matrix for tumor spheroid formation

Creating multicellular tumor spheroids is critical for characterizing anticancer treatments since they may provide a better model of the tumor than conventional monolayer culture. Moreover, tumor cell interaction with the extracellular matrix can determine cell organization and behavior. In this work, a microfluidic system was used to form cell-laden core-shell beads which incorporate elements of the extracellular matrix and support the formation of multicellular spheroids. The bead core (comprising a mixture of alginate, collagen, and reconstituted basement membrane, with gelation by temperature control) and shell (comprising alginate hydrogel, with gelation by ionic crosslinking) were simultaneously formed through flow focusing using a cooled flow path into the microfluidic chip. During droplet gelation, the alginate acts as a fast-gelling shell which aids in preventing droplet coalescence and in maintaining spherical droplet geometry during the slower gelation of the collagen and reconstituted basement membrane components as the beads warm up. After droplet gelation, the encapsulated MCF-7 cells proliferated to form uniform spheroids when the beads contained all three components: alginate, collagen, and reconstituted basement membrane. The dose-dependent response of the MCF-7 cell tumor spheroids to two anticancer drugs, docetaxel and tamoxifen, was compared to conventional monolayer culture.     

题目：一种支持产品平台设计的多准则模块划分方法

目的：研究多准则约束下的产品模块划分方法,为企业建立稳健的模块化产品平台奠定基础。方法：采用改进的多目标进化算法对建立的多准则模块划分数学模型求解,并采用模糊集合评价机制进行最优解的寻取,得到基于多准则模块划分方法的产品模块划分结果。结论：通过改进的多目标进化算法求解多准则模块划分模型,能够得到有效支持产品平台设计的产品模块划分方案。通过与已有优化方法的比较验证了本文提出的多准则模块划分方法的优越性。     

高校科技成果转化团队知识共享的演化博弈分析

针对高校科技成果转化团队成员知识共享的自身特征和影响因素,做出假设、设置变量,构建高校科技成果 转化团队成员知识共享的演化博弈模型,并对其进行均衡点分析,得出各影响因素对知识共享的作用关系,最后提出 促进高校科技成果转化团队知识共享的对策建议。     

RRM1 gene expression in peripheral blood is predictive of shorter survival in Chinese patients with advanced non-small-cell lung cancer treated by gemcitabine and platinum

Objective  

To evaluate the predictive values of gene expressions of ribonucleotide reductase M1 (RRM1) and breast cancer susceptibility gene 1 (BRCA1) in peripheral blood from Chinese patients with non-small-cell lung cancer (NSCLC) treated with gemcitabine plus platinum.     

Evaluation of the antioxidant effects of four main theaflavin derivatives through chemiluminescence and DNA damage analyses

Theaflavins (TFs) are the dimers of a couple of epimerized catechins, which are specially formed during black tea fermentation. To explore the differences among four main TF derivatives (theaflavin (TF₁), theaflavin-3-gallate (TF₂A), theaflavin-3′-gallate (TF₂B), and theaflavin-3,3′-digallate (TF₃)) in scavenging reactive oxygen species (ROS) in vitro, their properties of inhibiting superoxide, singlet oxygen, hydrogen peroxide, and the hydroxyl radical, and their effects on hydroxyl radical-induced DNA oxidative damage were systematically analyzed in the present study. The results show that, compared with (−)-epigallocatechin gallate (EGCG), TF derivatives were good antioxidants for scavenging ROS and preventing the hydroxyl radical-induced DNA damage in vitro. TF₃ was the most positive in scavenging hydrogen peroxide and hydroxyl radical, and TF₁ suppressed superoxide. Positive antioxidant capacities of TF₂B on singlet oxygen, hydrogen peroxide, hydroxyl radical, and the hydroxyl radical-induced DNA damage in vitro were found. The differences between the antioxidant capacities of four main TF derivatives in relation to their chemical structures were also discussed. We suggest that these activity differences among TF derivatives would be beneficial to scavenge different ROS with therapeutic potential.     

越南华文新文学概况及研究述评

越南华文新文学(简称越华文学)形成于抗日战争时期,起初为中国抗战文学的海外版,后来逐步走向本土化。越战时期,以现代诗为代表的越华文学已经形成了自己的特色,在东南亚各国中出类拔萃,至今仍是越华文学难以再现的高峰。长期以来,基于复杂的历史因素,越华文学的资料难觅,研究十分寂寞。如今,在新的历史时期,越华文学正逐步受到研究者的关注,有关资料也渐渐浮出水面。本文一方面梳理了越华文学的发展历程,另一方面对越华文学的研究现状进行反思。     

河南新型城镇化建设再思考

在第三次世界城镇化的浪潮中,为创造性地促进内需、解决城乡统筹,城镇化成为破解矛盾的关键抓手.河南是农业大省和人口大省,城镇化的压力较大,因此在新型城镇化建设中难题较多,最主要的是人口转移挑战大,土地和资金等资源支撑不足,气候环境破坏严重.考虑到河南省区域广而发展不平衡的严峻现实,在新型城镇化建设中务必要以协调为主线,以城镇体系的合理布局为原则,以“化农”为根本任务,以城镇低碳经济为方向,合理解决传统城镇化弊病.     

Relationship Reciprocation Modulates Resource Allocation in Adolescent Social Networks: Developmental Effects

Adolescence is characterized as a period of social reorientation toward peer relationships, entailing the emergence of sophisticated social abilities. Two studies (Study 1: N = 42, ages 13–17; Study 2: N = 81, ages 13–16) investigated age group differences in the impact of relationship reciprocation within school‐based social networks on an experimental measure of cooperation behavior. Results suggest development between mid‐ and late adolescence in the extent to which reciprocation of social ties predicted resource allocation. With increasing age group, investment decisions increasingly reflected the degree to which peers reciprocated feelings of friendship. This result may reflect social‐cognitive development, which could facilitate the ability to navigate an increasingly complex social world in adolescence and promote positive and enduring relationships into adulthood.