神锢的松动

正如前所述,欧洲历史上的中世纪是个"黑暗时代"。作为当时封建社会的精神支柱,基督教教会把上帝当做绝对的权威,建立了一套严格的等级制度。人的一切思想和行为都必须依《圣经》而为,否则就要受到教会的制裁,甚至被教会设立的宗教审判所处以各种残酷的死刑。在教会的管制下,中世纪的文学艺术死气沉沉,科学技术也没有多少进展。11世纪以后的欧洲,随着经济的复苏与发展、城市的兴起以及生活水平的提高,人们逐渐     

丙泊酚应用于无痛人工流产800例分析

目的:探讨丙泊酚在无痛人工流产术中的应用效果.方法:将886例早孕未产妇女和/或有剖宫产史妊娠妇女分为试验组和对照组,试验组800例,对照组86例.不采取镇痛麻醉的86例为对照组,试验组对人工流产病人施行丙泊酚静脉全身麻醉,并静脉给阿托品,其余操作同对照组.观察比较两组术中反应、手术时间、出血量与人工流产综合征的发生情况.结果:试验组病人无痛苦,舒适满意,手术时间明显缩短,无一例发生人工流产综合征.对照组69例(80.2%)诉疼痛难忍,11例(12.8)诉下腹痛但可以忍受,6例患者(7.0%)完全不痛.结论:丙泊酚具有高效,显效快速和安全的特点,静脉给丙泊酚可防止人工流产综合征的发生.     

激光处理植物种子产生的效应概述

大量研究表明,激光处理植物种子,会对植物种子性能及其萌发的植物体产生各种各样的影响.光对植物体的生长发育起着重要的作用,各种植物体在自然光的环境中形成了稳定的生理形态,在短时间内种子及其以后萌发的植物体不会有生理形态上的明显变化.激光不是自然光,用激光处理植物种子会对植物种子性能及其萌发的植物体产生各种各样的影响.本文论述了激光处理对种子及其以后萌发的植物体产生的效应影响进展.     

A parameter uniform essentially firsorder convergent numerical method for a parabolic system of singularly perturbed differential equations of reaction—diffusion type with initial and Robin boundary conditions

In this paper,a class of linear parabolic systems of singularly perturbed second-order differential equations of reaction-diffusion type with initial and Robin boundary conditions is considered.The components of the solution u→ of this system are smooth,whereas the components of αu→/αx exhibit parabolic boundary layers.A numerical method composed of a classical finite difference scheme on a piecewise uniform Shishkin mesh is suggested.This method is proved to be first-order convergent in time and essentially first-order convergent in the space variable in the maximum norm uniformly in the perturbation parameters.     

做好摇蚊染色体实验的几点体会

双翅目昆虫果蝇、摇蚊已成为观察染色体实验的经典材料,结合作者实践中的体会,谈几点做好本实验应注意的问题,重点是:幼虫要看颜色,唾腺要看形态及透明度,染色要把握好时间,压片要经过冷激等.     

Insulin resistance in diabetes: The promise of using induced pluripotent stem cell technology

Insulin resistance(IR)is associated with several metabolic disorders,including type 2 diabetes(T2D).The development of IR in insulin target tissues involves genetic and acquired factors.Persons at genetic risk for T2D tend to develop IR several years before glucose intolerance.Several rodent models for both IR and T2D are being used to study the disease pathogenesis;however,these models cannot recapitulate all the aspects of this complex disorder as seen in each individual.Human pluripotent stem cells(hPSCs)can overcome the hurdles faced with the classical mouse models for studying IR.Human induced pluripotent stem cells(hiPSCs)can be generated from the somatic cells of the patients without the need to destroy a human embryo.Therefore,patient-specific hiPSCs can generate cells genetically identical to IR individuals,which can help in distinguishing between genetic and acquired defects in insulin sensitivity.Combining the technologies of genome editing and hiPSCs may provide important information about the genetic factors underlying the development of different forms of IR.Further studies are required to fill the gaps in understanding the pathogenesis of IR and diabetes.In this review,we summarize the factors involved in the development of IR in the insulin-target tissues leading to diabetes.Also,we highlight the use of hPSCs to understand the mechanisms underlying the development of IR.     

基于染色体计数和ITS序列初步探讨横断山区柴胡属植物(伞形科)的系统发育

横断山区是中国柴胡属Bupleurum植物的分布中心。本文对横断山区6个种2变种进行了染色体记数报道,其中4个种2变种是首次报道。对横断山区的10个种4个变种、中国北方（河北和黑龙江）的3个种的nrDNA ITS进行测序,同时从GenBank里面下载同属的来自非洲和地中海西部的16个nrDNA ITS序列数据,结合染色体数目变化结果,初步探讨了横断山区柴胡属植物的系统发育。结果表明横断山区可能是现代柴胡属植物的频度中心和多样分布中心之一。它们的祖先种可能是非洲北部的木本柴胡属植物B.fruticosum,或者是地中海西部的柴胡属植物,推测是通过中东和高加索扩散而形成的,其中与非洲南部特有种B.mundtii的亲缘关系也较近;染色体基数演化趋势是：8是较原始基数,6和7是次生基数,其染色体异基数变异和多倍化可能是物种形成、进化以及向外扩散的主要方式;在ITS系统发育树中,中国柴胡属植物染色体基数为8的种类聚为一支,染色体基数为6和7的种类聚为了一支,不支持舒璞等（1998）关于中国柴胡属的属下分类系统。结合已有的形态学、细胞学、孢粉学证据和ITS系统发育树,建议窄竹叶柴胡B.marginatum var.stenophyllum独立成种。     

Dynamical behaviors of the generalized hematopoiesis model with discontinuous harvesting terms

This paper is concerned with the generalized hematopoiesis model with discontinuous harvesting terms.Under the framework of Filippov solution,by means of the differential inclusions and the topological degree theory in set-valued analysis,we have established the existence of the bounded positive periodic solutions for the addressed models.After that,based on the nonsmooth analysis theory w让 h Lyapunov-like approach,we employ a novel argument and derive some new criteria on the uniqueness,global exponential stability of the addressed models and convergence of the corresponding autonomous case of the addressed models.Our results extend previous works on hematopoiesis model to the discontinuous harvesting terms and some corresponding results in the literature can be enriched and extended.In addition,typical examples with numerical simulations are given to illustrate the feasibility and validity of obtained results.     

Current methods for the maturation of induced pluripotent stem cellderived cardiomyocytes

Induced pluripotent stem cells(iPSCs) were first generated by Yamanaka and colleagues over a decade ago. Since then, iPSCs have been successfully differentiated into many distinct cell types, enabling tissue-, disease-, and patientspecific in vitro modelling. Cardiovascular disease is the greatest cause of mortality worldwide but encompasses rarer disorders of conduction and myocardial function for which a cellular model of study is ideal. Although methods to differentiate iPSCs into beating cardiomyocytes(iPSC-CMs) have recently been adequately optimized and commercialized, the resulting cells remain largely immature with regards to their structure and function,demonstrating fetal gene expression, disorganized morphology, reliance on predominantly glycolytic metabolism and contractile characteristics that differ from those of adult cardiomyocytes. As such, disease modelling using iPSC-CMs may be inaccurate and of limited utility. However, this limitation is widely recognized, and numerous groups have made substantial progress in addressing this problem. This review highlights successful methods that have been developed for the maturation of human iPSC-CMs using small molecules,environmental manipulation and 3-dimensional(3 D) growth approaches.     

水麻的化学成分研究(英文)

从水麻(Debregeasia orientalis C J Chen)地上部分的95%乙醇提取物中首次分离到18个化合物,应用波谱方法或与已知品对照的手段鉴定它们为棕榈酸 (1)、正二十烷酸 (2)、正二十烷酸甲酯 (3)、β-谷甾醇 (4)、Monogynol A (5)、白桦酸 (6)、Hederagenin (7)、β-胡萝卜甙 (8)、18αH-20(29)-烯-3-酮-乌苏烷 (9)、3,4-开环-20(29)-烯-乌苏烷-3-酸 (10)、Pomolic acid (11)、表儿茶素 (12)、儿茶素 (13)、槲皮素 (14)、槲皮素-3-O-β-D-吡喃葡萄糖苷 (15)、紫丁香苷 (16)、紫丁香酚苷 (17)和山萘酚-3-O-β-D-芦丁糖苷 (18).     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).