The role of duckweed in bio-liquid fuel production and environmental protection

With the world economic development, population growth and improvement of people＇ s living standard, the energy shortage has become the core issue of restricting the development of the world economy. China faces serious energy crisis and environmental problems, so the development of biofuels in China is vital. This paper introduces the advantages of duckweed for energy production, summarizes the research results of Chengdu Institute of Biology on duckweed, and provides the direction of its further studv.     

论权力话语和优伶性别角色

中国优伶具有＂卑贱者＂和＂色情者＂的社会性别角色,它的形成有其最原始和最基础的控制力量,即权力采用＂话语＂的手段,以抵消优伶在舞台和现实中任何可能造成性别和权利的混乱乃至颠倒倾向,而在此背后,权力话语对中国优伶性别角色的组织和控制,实质上是对经济及其在此之上的政治权力的一种维护和巩固,或者说是,经济及其在此之上的政治权力的一种本能提防和警戒。     

The major Vibrio cholerae autoinducer and its role in virulence factor production

Vibrio cholerae, the causative agent of the human disease cholera, uses cell-to-cell communication to control pathogenicity and biofilm formation. This process, known as quorum sensing, relies on the secretion and detection of signalling molecules called autoinducers. At low cell density V. cholerae activates the expression of virulence factors and forms biofilms. At high cell density the accumulation of two quorum-sensing autoinducers represses these traits. These two autoinducers, cholerae autoinducer-1 (CAI-1) and autoinducer-2 (AI-2), function synergistically to control gene regulation, although CAI-1 is the stronger of the two signals. V. cholerae AI-2 is the furanosyl borate diester (2S,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuran borate. Here we describe the purification of CAI-1 and identify the molecule as (S)-3-hydroxytridecan-4-one, a new type of bacterial autoinducer. We provide a synthetic route to both the R and S isomers of CAI-1 as well as simple homologues, and we evaluate their relative activities. Synthetic (S)-3-hydroxytridecan-4-one functions as effectively as natural CAI-1 in repressing production of the canonical virulence factor TCP (toxin co-regulated pilus). These findings suggest that CAI-1 could be used as a therapy to prevent cholera infection and, furthermore, that strategies to manipulate bacterial quorum sensing hold promise in the clinical arena.     

The role of microbial mats in the production of reduced gases on the early Earth.

The advent of oxygenic photosynthesis on Earth may have increased global biological productivity by a factor of 100-1,000 (ref. 1), profoundly affecting both geochemical and biological evolution. Much of this new productivity probably occurred in microbial mats, which incorporate a range of photosynthetic and anaerobic microorganisms in extremely close physical proximity. The potential contribution of these systems to global biogeochemical change would have depended on the nature of the interactions among these mat microorganisms. Here we report that in modern, cyanobacteria-dominated mats from hypersaline environments in Guerrero Negro, Mexico, photosynthetic microorganisms generate H2 and CO-gases that provide a basis for direct chemical interactions with neighbouring chemotrophic and heterotrophic microbes. We also observe an unexpected flux of CH4, which is probably related to H2-based alteration of the redox potential within the mats. These fluxes would have been most important during the nearly 2-billion-year period during which photosynthetic mats contributed substantially to biological productivity-and hence, to biogeochemistry-on Earth. In particular, the large fluxes of H2 that we observe could, with subsequent escape to space, represent a potentially important mechanism for oxidation of the primitive oceans and atmosphere.     

人参果胶SB对免疫细胞因子分泌的双向调节作用

以人参中的重要活性成分——人参果胶为实验材料,研究分析了其对免疫细胞因子分泌的影响.结果表明,人参果胶SB对人单核细胞THP-1分泌细胞因子IL-8及对小鼠脾细胞分泌细胞因子IL-2均具有明显的双向调节作用,即低浓度的人参果胶促进免疫细胞因子的分泌,而高浓度的人参果胶却呈现抑制作用.从细胞免疫学的角度初步揭示了人参的双...     

铁路工地拌和站生产信息采集终端软件开发与应用

为了解决我国铁路建筑信息化存在的一些问题,开发了一款铁路工地拌和站生产信息采集终端软件,它可用于实时采集并传输拌和站生产信息.此软件采用数据库访问中间件、无线传输单元和数据加密等多种技术手段,具有兼容性强、格式统一和适用范围广等优点.此软件已经在多条铁路线的工程建设管理中应用,实现了铁路拌和站生产信息的实时和准确的采集.     

计算机网络技术在图书馆采访工作中的应用

计算机网络技术的应用，产生了新的采购方式：电子商务和不完全电子商务。同时这些技术的应用使采访者与外界的信息交流变得便捷；采访数据可由采访人员输入或从网络引入并且可在图书馆多种工作环节中重复使用；采访查重、订购、统计可利用机读数据和网络设备轻松准确完成。     

透射层析成像中完全投影数据的获取

在证明典型跨孔方式所获投影数据提不完全的基础上，首次提出了四种在采用离散图像重建技术进行地震透射波走时反演层析成像时的完全投影数据的采集系统，并比较了四种采集系统所获数据在迭代反演时的收敛速度，最后给出了模型试验结果。     

论奥运竞技的性别平等取向

奥运竞技男女性别的平等化表现为项目设置与参赛人数的平等、决策与管理的平等、机会与资源的平等.平等化的趋向是人类文明的标志,是女性长期不懈斗争以及男性运动、管理权力不断妥协的产物,具有重大的社会和生命价值.由于历史的原因,目前人们在观念与操作层面上还存在着许多问题,有待于提高认识,促进竞技运动的进一步健康发展.     

促性腺激素(FSH)对甾类激素合成调节作用的研究

首先分离出23日龄SD品系大鼠的卵巢颗粒细胞,然后进行无血清细胞培养,采用放射免疫的方法分别鉴定了不同剂量、不同培养时间促性腺激素(FSH)对颗粒细胞中甾类激素合成的影响,结果表明,甾类激素合成受FSH的影响,并且具有浓度和时间依赖性.     

一种串行脉冲采集的设计与实现方法

设计了一种基于PXI总线的数据采集系统,以LabVIEW为软件编程平台,结合基于总线的数据采集技术的优势,并弥补了以往数据采集系统应用于3路串行脉冲信号时数据量大、译码困难的缺陷,经现场测试,该套系统运行稳定可靠,结果准确,达到了预期的效果.     

The ecological cost of sex

Why sex prevails in nature remains one of the great puzzles of evolution. Sexual reproduction has an immediate cost relative to asexual reproduction, as males only express their contribution to population growth through females. With no males to sustain, an asexual mutant can double its relative representation in the population in successive generations. This is the widely accepted 'twofold cost of males'. Many studies have attempted to explain how sex can recoup this cost from fitness benefits associated with the recombination of parental genotypes, but these require complex biological environments that cycle over evolutionary timescales. In contrast, we have considered the ecological dynamics that govern asexual invasion. Here we show the existence of a threshold growth rate for the sexual population, above which the invasion is halted by intraspecific competition. The asexual population then exerts a weaker inhibitory effect on the carrying capacity of the sexual population than on its own carrying capacity. The stable outcome of this is coexistence on a depleted resource base. Under these ecological circumstances, longer-term benefits of sex may eventually drive out the asexual competitor.     

雷达信号采集系统的设计与实现

基于Windows/PXI技术的传统数据采集系统不能保证采集的准确性和可靠性,有时出现"丢数据"的现象.针对这些问题,通过分析CPCI总线下数据采集卡的特性,设计实现了一种基于VxWorks/CPCI技术的雷达回波信号数据采集系统.该系统满足了数据采集的实时性、可靠性与准确性要求,并加入了网络FTP传输功能,实现了采集数据的实时传输,简化了一些繁琐的数据导出操作.同时使用VC++6.0编写分析软件,对采集到的雷达回波信号数据进行分析,取得了较满意的实验结果,进一步确认了该采集系统的可行性与可靠性.     

高速数据采集卡的设计

介绍了高速数据采集卡的设计方法,给出了系统硬件的各个部分的组成,对设计到的关键技术进行了分析说明,最后给出实验结果并进行了误差分析,本采集卡可以采集到30GHz的高频信号。     

多功能数据采集卡PCL-812PG及在温度控制中的应用

介绍了PCL-812PG数据采集卡及其原理，并讨论了其在温度控制中的应用。     

心电信号与气象因子同步采集系统的研究

研究发现,气象因子的变化会影响人体生理参数的改变。目前的研究都是基于事后的统计分析。为此设计了一种动态采集系统,用于对气象因子和心电信号进行24h的同步采集,从而揭示气象因子变化与心电信号之间的对应关系。系统选W78LE516单片机和CPLD来构造控制电路,用读写速度快、功耗低的低电压外部数据存储器CF卡存储采集完的信号。最终采集到的数据可以在上位机上显示波形。