Growth, photosynthesis and podophyllotoxin accumulation of Dysosma versipellis in response to a light gradient and conservation implications

Dysosma versipellis (Hance) M. Cheng ex Ying (Berberidaceae) is a rare and vulnerable, perennial herb endemic to China with pharmaceutical significance. Increasing habitat loss and over-exploitation of the plant has severely affected the plant’s in situ conservation, necessitating ex situ conservation and commercial cultivation. The light regime is a critical environmental factor contributing to successful ex situ conservation via efficient production of biomass and secondary metabolites. We investigated th...     

泥质烃源岩密度分组及有机质赋存类型初探

选取济阳坳陷沙河街组深湖相暗色泥岩为研究对象,通过不同密度ZnBr2重液浮选,将样品分离成多个密度组分,对各组分检测透射光、荧光、X光衍射等,揭示不同组分有机质赋存类型的差异性.分析结果表明,①组分(密度ρ<1.6g.cm-3)以颗粒有机质为主,有机质与矿物无明显紧密结合关系;②,③组分(1.6g.cm-3<ρ<2.2g.cm-3,ρ>2.2g.cm-3)多见无定形有机质分散于细粒矿物相中,呈橙黄-亮黄色荧光,反映有机质与矿物颗粒紧密共生的赋存特征.进一步对不同密度组分有机质分配的研究表明,①组分结合了烃源岩总有机质质量不到1%;②,③组分结合了烃源岩中90%以上质量的有机质.这反映了有机质和矿物颗粒共生的赋存形式在有机质保存中不可忽视的重要地位.     

探讨水闸电气设备控制系统应用

随着对水力资源的开发与利用的逐步重视,许多水利工程已完成或正在兴建.文章详细介绍了电气控制中的常用一、二次回路和二合一精密行程开关;闸门开度传感器;闸门开度数显控制仪;水位传感器和水位仪的工作原理及计算机在水闸中的应用.     

局域网网络安全管理技术分析

安全问题始终是制约局域网进一步推广的关键因素,文章分析现今局域网网络安全威胁的因素,以及相关的安全管理技术.     

精神因素导致不孕不育临床调查及治疗

近年来不孕不育患者发病率逐年升高,不孕妇女的沮丧情绪一般会在不孕的第二到第三年之间达到顶点。但是,由于她本身和家人都把注意力放到了解决不孕这个问题上,从而忽视了精神层面。而且,大夫也反对准备怀孕的妇女服用抗抑郁症药物,因为这一类药物会导致不孕,所以精神安慰治疗以心理开导干预的手段介入不孕妇女的精神问题。当然,女性在不孕的第一年就应该考虑到自己是否该减压了,越早接受治疗效果越好。     

矿务局网络规划

局域网是一个覆盖单位所有建筑和机构的综合网络。网络建设总体目标是采用先进实用的网络通信技术和计算机技术,文章从组网图、组网设备分析、网络结构分析等方面对校园网的规划做一介绍。     

An integrated semiconductor device enabling non-optical genome sequencing

The seminal importance of DNA sequencing to the life sciences, biotechnology and medicine has driven the search for more scalable and lower-cost solutions. Here we describe a DNA sequencing technology in which scalable, low-cost semiconductor manufacturing techniques are used to make an integrated circuit able to directly perform non-optical DNA sequencing of genomes. Sequence data are obtained by directly sensing the ions produced by template-directed DNA polymerase synthesis using all-natural nucleotides on this massively parallel semiconductor-sensing device or ion chip. The ion chip contains ion-sensitive, field-effect transistor-based sensors in perfect register with 1.2 million wells, which provide confinement and allow parallel, simultaneous detection of independent sequencing reactions. Use of the most widely used technology for constructing integrated circuits, the complementary metal-oxide semiconductor (CMOS) process, allows for low-cost, large-scale production and scaling of the device to higher densities and larger array sizes. We show the performance of the system by sequencing three bacterial genomes, its robustness and scalability by producing ion chips with up to 10 times as many sensors and sequencing a human genome.     

Shank3 mutant mice display autistic-like behaviours and striatal dysfunction

Autism spectrum disorders (ASDs) comprise a range of disorders that share a core of neurobehavioural deficits characterized by widespread abnormalities in social interactions, deficits in communication as well as restricted interests and repetitive behaviours. The neurological basis and circuitry mechanisms underlying these abnormal behaviours are poorly understood. SHANK3 is a postsynaptic protein, whose disruption at the genetic level is thought to be responsible for the development of 22q13 deletion syndrome (Phelan-McDermid syndrome) and other non-syndromic ASDs. Here we show that mice with Shank3 gene deletions exhibit self-injurious repetitive grooming and deficits in social interaction. Cellular, electrophysiological and biochemical analyses uncovered defects at striatal synapses and cortico-striatal circuits in Shank3 mutant mice. Our findings demonstrate a critical role for SHANK3 in the normal development of neuronal connectivity and establish causality between a disruption in the Shank3 gene and the genesis of autistic-like behaviours in mice.     

剪切闸板防喷器剪切性能评价

剪切闸板防喷器是井控设备的重要组成部分之一,其作用是在钻井过程中遇到突发情况时及时剪断钻杆并密封井口,其剪切性能直接关系到钻井作业的安全.以某新型上直下V结构的剪切闸板防喷器为研究对象,通过显示动力学模块对剪切闸板剪切钻杆的过程进行数值仿真模拟,分析研究闸板的剪切性能.并用该剪切闸板分别剪切5 in和5.5 in两种不...     

支持地铁车体开发的工程数据库系统

在车体产品数据模块和数据库功能分析的基础上,建立以SQL Server 2000为后台数据库,以Java为W eb Service开发工具的工程数据库系统,完成前台功能化查询、可视化查询和参数化查询的功能设计.数据库内存储所有已建CAD模型和CAE模型的一般信息、分析结果信息及模型指针.该数据库系统管理设计过程、图纸文件、设计结果和分析结果,支持产品的设计变更、审批和发布,实现快速设计信息的检索与查询.实际应用表明,该系统能有效地管理车体开发中的产品数据.