幽门螺杆菌感染并发消化性溃疡的危险因素及预防对策分析

目的:分析幽门螺杆菌感染并发消化性溃疡的危险因素,并实施预防对策。方法:选取我院收治的消化性溃疡的患者201例,对其临床资料进行回顾性分析,分析其危险因素。结果:消化性溃疡患者201例,Hp感染162例,Hp阳性率80.60%,不同类型的消化性溃疡的Hp阳性率比较,差异无统计学意义(P0.05)。单因素分析结果显示,年龄在36-60岁、共食、男性、暴饮暴食、喜爱辛辣食物、吸烟饮酒、个人卫生、家族病史、以往病史,均是消化性溃疡Hp感染的高危因素。进餐习惯、喜欢酸奶、个人卫生均是Hp感染的保护因素,而暴饮暴食、喜爱辛辣食物、年龄、以往病史、吸烟饮酒、家族病史均是Hp感染的危险因素。结论:分餐习惯、喜欢酸奶、个人卫生均是Hp感染的保护因素,而暴饮暴食、喜爱辛辣食物、年龄、以往病史、吸烟饮酒、家族病史是Hp感染的危险因素,进行有针对性的预防可降低疾病发生率。     

Of beta diversity,variance, evenness,and dissimilarity

The amount of variation in species composition among sampling units or beta diversity has become a primary tool for connecting the spatial structure of species assemblages to ecological processes. Many different measures of beta diversity have been developed. Among them, the total variance in the community composition matrix has been proposed as a single‐number estimate of beta diversity. In this study, I first show that this measure summarizes the compositional variation among sampling units after nonlinear transformation of species abundances. Therefore, it is not always adequate for estimating beta diversity. Next, I propose an alternative approach for calculating beta diversity in which variance is substituted by a weighted measure of concentration (i.e., an inverse measure of evenness). The relationship between this new measure of beta diversity and so‐called multiple‐site dissimilarity measures is also discussed.     

微生物学模块式自设计研究性实验的构建与教学实践

为了以低成本、低课时、高个性化方式让低年级学生既能学习基本实验技术,又都有机会参与研究性实验,构思了以基本实验技术为依托的微生物学模块式自设计研究性实验,即教师以模块式专题形式提出系列实验项目,学生自主选择题目、思考和设计、实施操作、分析结果而教师恰当指导的实验教学方式,并将其在3年4轮的微生物学实验教学中应用。详细叙述了模块式自设计研究性实验设计思路和实施方法及实施中学生和教师的行为与表现,并分析了从3个班级收回的包含34个问题的实验教学效果调查问卷,深入探讨了该方法存在的不足和改进方法。教学实践表明,这种教学方法不会导致教师数量、实验成本、学时数的显著增加,对于较大规模学生的研究性实验具有较强的实用性和可行性;144份学生反馈问卷中每个问题平均得分均在4分以上(满分5分),表明有利于提高学生的多方面素质,使学生受到基本的科学研究素质和能力的初步训练;88%-96%的学生认为它是有效的教学方式;研究性实验的形式、学生主动性、实验方案设计的科学性、实验结果分析和讨论等方面还有待完善。     

抗生素与抗菌药物协同作用防控生物膜的研究进展

生物膜(Biofilm)是指微生物为适应周围环境,黏附于介质表面并被其自身分泌的胞外基质包裹而形成的一种复杂的、高度异质的聚合结构。生物膜对宿主防御和药物具有很强的抵御能力,使用单一药物防治往往效果不显著,而利用协同作用将不同抗菌药物的优势联合起来用于生物膜的防控则优势明显。重点阐述了抗生素与抗生素、抗生素与中药、抗生素与噬菌体、抗生素与酶的协同作用研究,以期为生物膜的防控提供新思路。     

茶树诱导抗虫性的研究进展

为了抵御植食性昆虫的为害,植物在进化过程中形成了包括组成抗性和诱导抗性在内的复杂防御体系.在通过受体识别茶树害虫为害后,茶树会启动早期信号事件,继而激活茉莉酸、水杨酸、乙烯和赤霉素等植物激素信号通路,从而引起次生代谢物的积累,最终对害虫产生直接和间接抗性.基于近年来茶树害虫为害诱导的茶树防御反应及其相关调控机理的研究进...     

喀斯特石漠化地区不同恢复和重建措施对土壤质量的影响

采取4种不同恢复和重建措施对典型喀斯特石漠化地区进行了13年的生态治理研究.结果表明,喀斯特严重石漠化区（对照）植物多样性极低,土壤肥力极差,生态环境极为恶劣;改为花椒种植或多种乔-灌-藤混交种植后,植物多样性明显增大,土壤质量得到一定程度恢复,生态系统朝着良性循环方向发展;采取封山育林措施后,林下植被层和群落多样性恢复得最快,林地土壤质量得到较快的恢复;保留较好的喀斯特次生林中植物多样性较高,土壤质量最好.采用合适的生物措施,辅以必要的工程措施,是促进严重喀斯特石漠化地区生态重建的有效途径之一.     

不同间伐措施对乳源木莲生长的影响

由于间伐措施不同,杉木与乳源木莲混交林中的乳源木莲生长差异显著。间伐适时,乳源木莲的胸径、树高生长量明显增加,材积速生期延长,且17年生仍处在速生期;而逾期间伐,林分密度偏大,则混交林中乳源木莲生长受抑制,速生期提早结束,生长不良。作者认为,为提高杉莲混交林的经营效果,适时间伐、密度合理至关重要。     

The History of Toxoplasma gondii—The First 100 Years

ABSTRACT. In this paper the history of Toxoplasma gondii and toxoplasmosis is reviewed. This protozoan parasite was first discovered in 1908 and named a year later. Its medical importance remained unknown until 1939 when T. gondii was identified in tissues of a congenitally infected infant, and veterinary importance became known when it was found to cause abortion storms in sheep in 1957. The discovery of a T. gondii specific antibody test, Sabin–Feldman dye test in 1948 led to the recognition that T. gondii is a common parasite of warm‐blooded hosts with a worldwide distribution. Its life cycle was not discovered until 1970 when it was found that felids are its definitive host and an environmentally resistant stage (oocyst) is excreted in feces of infected cats. The recent discovery of its common infection in certain marine wildlife (sea otters) indicates contamination of our seas with T. gondii oocysts washed from land. Hygeine remains the best preventive measure because currently there is no vaccine to prevent toxoplasmosis in humans.