生物阻抗测量系统的改良

目的:针对目前现有的生物阻抗测量系统测量速度和精度不够的问题,提出相应的改进方法。方法:在信号发生部分采用AD公司的ADuC847微处理器作为核心微处理器;在信号采集部分采用Atmel公司的AT91RM9200微控制器芯片和TI公司的ADS1256芯片作为核心芯片。结果:生物阻抗测量系统的信号发生精度提高到12位,信号采集精度提高到24位,速度提高到30,000SPS。结论:对信号发生和信号采集方面速度和精度的提高,有效地提高了整个测量系统的速度和精确度。     

压电体声波阻抗生物传感器技术在血培养中的应用评价

评价全自动压电体声波阻抗生物传感器血液培养系统的应用价值,并与Bactec9120血培养系统相比较。将2005年7~12月临床标本407例分别同时接种于2种不同的血培养系统中进行培养,对其阳性检出率、阳性检出时间、假阳性率及相关因素进行综合性评估。407份标本全自动压电体声波阻抗生物传感器血液培养系统检测出阳性标本58株,阳性率为14.3%,平均检出时间为(11.58±7.62)h;Bactec9120血培养系统培养阳性菌株61株,阳性率为15.0%,平均检出时间为(18.71±12.89)h。经统计学处理,两种检测方法阳性率无显著性差异(χ2=0.089,P>0.5),但检出时间有显著性差异(t=3.64,P<0.001)。全自动压电体声波阻抗生物传感器血液培养系统快速、简单、准确、便宜,可在各医院推广使用。     

电化学阻抗谱在生物传感器研究中的应用进展

电化学阻抗谱(EIS)是近年快速发展起来的一种电化学分析方法。它具有良好的界面表征作用,特别适合于分析电极表面生物敏感膜的制备、生物学反应的动力学机制,已逐渐成为生物传感器研究的有效辅助方法。简要概述了EIS技术的原理,及其在各种生物传感器中的应用进展。     

基于生物阻抗谱的生物细胞活性免标记检测方法

目的 基于生物阻抗谱（bioelectrical impedance spectroscopy,BIS）技术,提出一种免标记的生物细胞活性实时检测方法。该方法依据不同浓度、生理、病理状态下细胞组织的电学特性差异来判断细胞是否具有活性,以协助医师在临床手术中快速精准定位患者烫伤组织并实现有效切除。方法 使用具有活性的斑马鱼胚胎干细胞来模拟人体烫伤组织,采用生物阻抗谱技术来鉴别细胞组织的生理状态。结果 在不同状态下,细胞的阻抗幅值变化有显著的差异,可以从中发现同等浓度下活性细胞的阻抗幅值比死亡细胞平均高出17.25%,活性细胞发生弛豫频率的时间也比死亡细胞早25%。结论 实验数据表明,生物阻抗谱法能有效区分胚胎干细胞的两类生理状态;从聚类区域中可以看出,BIS检测法具有明显的细胞活性及浓度区分能力,理论上能够快速地协助医师完成对患者烫伤组织检测。     

纳米多孔硅阻抗生物传感器的研究

构建了1种基于多孔硅材料,无需标记的纳米生物传感器,用于对牛血清白蛋白分子进行检测。通过对多孔硅进行表面处理,形成氧化膜,将抗体固定到多孔硅氧化层表面。在磷酸盐缓冲液中,通过电化学检测系统检测加入抗原后,传感器的阻抗值的变化。磷酸缓冲液（PBS）/抗体-氧化层/硅,构成电解液/绝缘层/半导体（electro-lyte-insulator-semiconductor,EIS）结构。传感器的线性检测范围为0.01～0.27mg/mL,检测限为0.01mg/mL。     

解析用于环境监测的生物传感技术

随着科技的不断进步,企业的不断发展,我国的经济水平有了很大的提升。但在实际的发展中,一切的一切都是建立在破坏环境的基础上,因此在将来的工作中必须对环境进行有效的保护。现今的一般方法和手段已经没有办法对环境进行有效的监测,更不要说保护环境。鉴于这样的情况,我们需要采取有效的措施来监测环境,获得确切的资料,也就是生物传感技术。这种技术从研究到实施经历了较长的时间,但取得的效果却非常好。     

生物被膜的形成及其电化学阻抗检测

生物被膜是细菌及其自身分泌的胞外聚合物组成的微生物群落,其形成是受多种机制共同调控的多阶段动态过程,具有较强的耐药性且难以清除,给医疗、食品等行业带来了巨大的威胁。近年来,生物被膜的相关研究领域备受关注,尤其是针对生物被膜的有效检测技术。本文在简要介绍生物被膜的特点、形成过程及群感效应对生物被膜的调控作用基础之上,总结了生物被膜常用的检测方法,重点针对电化学阻抗技术在生物被膜检测中的应用进行调研和讨论,并对基于微流控芯片的生物被膜电化学阻抗原位检测进行了综述和展望。     

生物传感器概述

生物传感器概述田桂英（中国农科院科技文献信息中心,１０００８１）生物传感器（Ｂｉｏｓｅｎｓｏｒｓ）是一种新兴的生物技术产品,在分析领域中具有极大的潜力和应用前景。生物传感器是传感器学科中的一个重要分支。八十年代中后期,世界上一些国家,特别是日本和欧美...     

多导联在线阻抗检测的实现与分析

目的：提出了一种基于多导联生理信号采集装置平台的快速、稳定、低功耗的在线阻抗测量方法。方法：在线阻抗测量的实现主要有两个关键技术：正弦信号恒流源和数字带通滤波器,都主要是采用软件的方式实现的。结果：单极性和双极性两种模式四组测量阻值的变异系数均不超过10%,测量值的稳定性较高,可以通过多次测量求平均值的办法来修正测量误差,修正后的误差明显优于修正之前的误差。结论：由单极性和双极性两种模式实际阻抗测量值可知,测量值能够准确反映电极与人体表皮的接触情况,此种方法稳定可靠。     

面向血液葡萄糖测量的生物组织阻抗模型

本文推导了细胞膜电容与血糖浓度之间的关系,并将这种关系应用到Pauly和Schwan提出的弛豫模型中,再将弛豫模型应用于多重Cole-Cole介电模型,最后通过介电模型得出阻抗模型,建立起人体血糖浓度与组织介电谱,阻抗谱之间的联系。通过分析发现,细胞膜电容随着血糖浓度增加而增大,且当血糖浓度趋于无穷大时,细胞膜电容等于血糖浓度为0时细胞膜电容的1.53倍。对介电谱的仿真得出,当外加信号频率小于1 MHz时,介电常数实部随着葡萄糖浓度改变而发生明显变化。阻抗谱的研究结果表明,随着葡萄糖浓度的升高,阻抗的实部减小,阻抗虚部模增大,且分别在频率为1.48 MHz和0.55 MHz时变化得最快。本文建立的模型为血糖无创检测提供了一种新的方法和手段。     

An Overview of the Introns-First Theory

We review the introns-first hypothesis a decade after it was first proposed. It is that exons emerged from non-coding regions interspersed between RNA genes in an early RNA world, and is a subcomponent of a more general ‘RNA-continuity’ hypothesis. The latter is that some RNA-based systems, especially in RNA processing, are ‘relics’ that can be traced back either to the RNA world that preceded both DNA and encoded protein synthesis or to the later ribonucleoprotein (RNP) world (before DNA took over the main coding role). RNA-continuity is based on independent evidence—in particular, the relative inefficiency of RNA catalysis compared with protein catalysis—and leads to a wide range of predictions, ranging from the origin of the ribosome, the spliceosome, small nucleolar RNAs, RNases P and MRP, and mRNA, and it is consistent with the wide involvement of RNA-processing and regulation of RNA in modern eukaryotes. While there may still be cause to withhold judgement on intron origins, there is strong evidence against introns being uncommon in the last eukaryotic common ancestor (LECA), and expanding only within extant eukaryotic groups—the ‘very-late’ intron invasion model. Similarly, it is clear that there are selective forces on numbers and positions of introns; their existence may not always be neutral. There is still a range of viable alternatives, including introns first, early, and ‘latish’ (i.e. well established in LECA), and regardless of which is ultimately correct, it pays to separate out various questions and to focus on testing the predictions of sub-theories.     

Phytoremediation—An Overview

The use of plants (directly or indirectly) to remediate contaminated soil or water is known as phytoremediation. This technology has emerged as a more cost effective, noninvasive, and publicly acceptable way to address the removal of environmental contaminants. Plants can be used to accumulate inorganic and organic contaminants, metabolize organic contaminants, and encourage microbial degradation of organic contaminants in the root zone. Widespread utilization of phytoremediation can be limited by the small habitat range or size of plants expressing remediation potential, and insufficient abilities of native plants to tolerate, detoxify, and accumulate contaminants. A better understanding and appreciation of the potential mechanisms for removing contaminants from the root zone and the interaction between plants, microorganisms, and contaminants will be useful in extending the application of phytoremediation to additional contaminated sites.     

An Overview of Fishing Rights

Coastal state management of marine harvests within 200-mile Exclusive Economic Zones was a new and innovative process during the period from the late 1970s through the 1980s. The spread of conservation-focused harvest management was a key step in the evolution of fishing rights, followed in some nations by a second step of creating more exclusive, individual or group fishing rights. The three main forms of more exclusive fishing rights – limited entry permits, individual fishing quotas (IFQs), and local community-based or co-operative harvesting – vary widely in content and detail. But, when successful, they all increase the economic efficiency of fisheries, and they reshape the economic and political landscape of fisheries. All three types, but particularly IFQs, may initiate radical changes in the economic organization of the fishery, ultimately changing who fishes, where and when they fish, the products sold, the balance of power among industry sectors, incentives to support conservation, the size of incomes from fishing, and the location of shore-side economic activity. Changes of this sort are bound to provoke controversy. The controversies over fishing rights take three forms: disagreements over the meaning and intent of fishing rights, disputes over the distribution of rights and associated economic gain, and concern for disruptions imposed on people who are dependent on the “old order”. This paper provides a short review of the underlying concepts, rights systems, and current controversies concerning fishing rights.     

An Overview of Epigenetic Assays

A significant portion of ongoing epigenetic research involves the investigation of DNA methylation and chromatin modification patterns seen throughout many biological processes. Over the last few years, epigenetic research has undergone a gradual shift and recent studies have been directed toward a genome-wide assessment. DNA methylation and chromatin modifications are essential components of the regulation of gene activity. DNA methylation effectively down-regulates gene activity by addition of a methyl group to the five-carbon of a cytosine base. Less specifically, modification of the chromatin structure can be carried out by multiple mechanisms leading to either the upregulation or down-regulation of the associated gene. Of the many assays used to assess the effects of epigenetic modifications, chromatin immunoprecipitation (ChIP), which serves to monitor changes in chromatin structure, and bisulfite modification, which tracks changes in DNA methylation, are the two most commonly used techniques. J. T. DeAngelis and W. J. Farrington are contributed equally.     

遗传生态学透视

遗传生态学透视何维明钟章成（西南师范大学生命科学系,重庆６３０７１５）ＡｎＯｖｅｒｖｉｅｗｏｆＧｅｎｅｃｏｌｏｇｙ．ＨｅＷｅｉｍｉｎｇ,ＺｈｏｎｇＺｈａｎｇｃｈｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＬｉｆｅＳｃｉ－ｅｎｃｅ,ＳｏｕｔｈｗｅｓｔＮｏｒｍａｌＵ...     

An Overview of the Archaeology of East Texas

Abstract

This brief survey attempts to define, and to offer explanations for, the major patterns of aboriginal adaptations presently recognizable in the eastern part of Texas. It is organized from a chronological point of view, but is more concerned with the processes and conditions that lead to changes in subsistence and social systems.     

An Overview of the Ecology of Antarctic Seals

Four species of seals occupy the pack-ice region of the oceanssurrounding the Antarctic Continent. These seals include thecrabeater (Lobodon cardnophagus), leopard (Hydrurga leptonyx),weddell (Leplonychotes weddellii), and ross (Ommatophoca rossii),and are true seals with special adaptations for living in thepack-ice region. Two other seal species, the southern elephantseal (Mirounga leonina) and the fur seal (Arctocephalus gazella)(the only eared seal of this region) generally occur furtherto the north and use land rather than ice during the periodof birth of young. This paper reviews the status of these species,and examines the generalecology of the four species that inhabitthe pack-ice zone. In general, the four species that occupythe pack-ice zone have specialized in habitats and habits sothat little overlap in dietsor habitat use exist among thesespecies. The exception is the interaction between the leopardand the crabeater which occupy the same regions and eat krill(Euphausia superba), particularly during the winter. The impactof the potential harvest of krill by man on these species isdiscussed. Further, the impact that recovery of the large baleenwhales that feedin this region during the summer is discussedwith regard to the changes that might occur as competition forkrill by the large vertebrate species increases.     

垂体瘤转化基因1研究进展

垂雄瘤转化基因1（PTTG1）,也被称为分离酶抑制蛋白基因,是近几年从大鼠垂体肿瘤中发现的癌基因。它不但可以与分离酶结合,使分离酶失活,从而抑制姐妹染色单体的分离,还具有转录激活活性。已有的染色质免疫共沉淀结合芯片数据显示,PTTG1不仅可以直接调控基因的转录,也可以与其他蛋白,如PTTG1结合因子（PBF）、p53、Spl、上游刺激因子1（USF1）等相互作用来调控下游基因的转录。在NIH3T3细胞中,PTTG1激活c-Mvc的转录,增强NIH3T3细胞在裸鼠体内的成瘤能力。PTTG1也能激活肿瘤细胞中成纤维细胞生长因子2（FGF2）的转录,从而促进肿瘤血管生成。PTTG1结合p53、抑制p21表达、激活周期蛋白D3的能力,提示它在凋亡、细胞周期和衰老方面廿．发挥作用。另外,PTTG1在肿瘤转移和肝癌的发生发展中也发挥着重要作用。我们简要综述了PTTG1的靶基因,及其在肝癌及肿瘤转祷中的研究进展。