生物无线传感器网络路由算法研究

生物无线传感器网络在通信时,传感器节点会对其邻近的人体组织产生有害的电磁辐射,并由此引出了温度问题.在生物无线传感器网络中,如只考虑节点的能量问题,则可能致使某部分组织因局部温度过高而受到损伤,因此,传统的传感器网络路由算法并不能完全适用.本文基于以上问题提出一种新的簇头转换算法,综合考虑节点的能量、温度等问题,为各节点设定优先级,选择优先级最高的节点作簇头节点.从而使传感器节点邻近组织的温度得到控制,并且各节点的剩余能量也较为均匀.与传统的算法相比,降低了网络节点对人体的损伤,同时延迟了第一个死亡节点的出现.     

生物传感器

生物传感器 (biosensor)是由固定化生物物质与适当的化学信号换能器件组成的生物电化学分析系统 ,具有特异识别生物分子的能力 ,并能检测生物分子与分析物之间的相互作用 ,用于微量物质的检测。1　生物传感器的优点生物传感器与传统的化学传感器和离线分析技术(如 HPLC或质谱 )相比 ,具有许多不可比拟的优势 ,如高度特异性 ,灵敏度高 ,稳定性好 ,成本低廉 ,体积小 ,能在复杂的体系中进行快速在线的连续检测。一般不需要样品的预处理 ,样品用量少 ,响应快 ,固定化敏感材料可反复多次使用 ,成本远低于大型分析仪器 ,易于推广普及。2　生物传…     

DNA生物传感器研究进展

本根据作用机理不同将ＤＮＡ生物传感器分为ＤＮＡ光化学传感器,ＤＮＡ电化学传感器和压电晶体传感器,并就几种方面的研究进展进行了综述。     

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...     

生物传感器的发展趋势

生物传感器是一种集现代生物技术与电子技术为一体的高科技产品。它是使用具有特异选择性的生物元件,如酶、抗体、受体、微生物、组织、DNA及单克隆等为基础,应用生物化学和电化学反应原理,将生化反应信号转化为电信号,经过放大及模/数转换,就可以测量出被测浓度的一种先进测试仪器。这种新型的传感器具有分子水平的识别功能。由于它容易进行电学放大,因而可以进行快     

用于环境监测的生物传感器

生物传感器是一项综合了多门学科的高新技术,具有特异性好、灵敏度高、分析速度快、能在复杂体系中在线连续监测等特点,被广泛用于生命科学、医学检验、食品安全及环境监测等多个领域。其中,在环境检测中的应用尤为令人瞩目。该文概括了生物传感器的原理、发展以及分类。并以各类生物学识别元件为依据将生物传感器分为酶传感器、微生物传感器、组织器官传感器、细胞器传感器、免疫传感器、DNA传感器等几种基本类型,分别回顾了各类生物传感器在环境监测中的应用情况,并对其应用前景进行了展望。     

热作用对肾组织光传输特性的影响

研究了热作用下的肾组织对532 nm和1064 nm波长的光学特性的影响。实验利用带积分球附件的分光光度计和采用反向倍增法获取组织的光学特性,结果表明热作用下的肾组织对532 nm和1 064 nm的吸收系数和约化散射系数都是随着加热温度的变化而变化的。在25℃到80℃的温度范围内,肾组织对532 nm的吸收系数和约化散射系数都分别显著地较其对1064 nm的吸收系数和约化散射系数要大。其对532 nm和1 064 nm的吸收系数的最大值都在80℃,其值分别为1.121 mm-1和0.269 mm-1,最小值都在25℃,其值分别为0.131 mm-1和0.019 mm-1。其对532 nm和1 064 nm的约化散射系数的最大值分别在80℃和70℃,其值分别为2.905 mm-1和0.705 mm-1,最小值都在25℃,其值分别为0.391 mm-1和0.184 mm-1。研究结果提示,热作用的温度是影响肾组织的吸收和散射特性的重要因素。     

氩离子对两种嘧啶碱基的损伤效应研究

对２５ｋｅＶ的氩离子束辐照两种嘧啶碱基（胞嘧啶,胞腺嘧啶）引起它们分子结构的变化进行了研究,通过紫外光谱的分析,得到了氩离子注入后两种嘧啶碱基的残余紫外吸收曲线;富里叶红外光谱仪的分析,说明两种嘧啶碱基各受到了一定程度的损伤使得红外吸收出现不同程度的减弱;茚三酮反应的测定证明了辐照后的样品中出现了新的化学成分－伯胺类物质。     

Continuous Monitoring of Extracellular Glucose Concentrations in the Striatum of Freely Moving Rats with an Implanted Glucose Biosensor

Abstract: We have used a glucose oxidase-based sensor implanted in the striatum of freely moving rats to determine the concentration of extracellular glucose in two distinct ways. With a modification of the zero net flux method, in which different concentrations of glucose are infused through a dialysis probe glued to the biosensor, we calculated the concentration at which there was no change in glucose current by regression analysis; this gave a concentration of 0.351 ± 0.016 m M . Calculating the concentration from the basal current and the in vitro calibration of the biosensor was not significantly different from this. The basal extracellular glucose concentration determined by either method remained constant over a period of several days. Infusion of 50 µ M veratridine through the adjacent dialysis probe caused a steep decrease in glucose current as soon as the drug reached the brain in contrast to the delayed fall (7.5 min) seen with microdialysis in previous experiments from this laboratory. These results demonstrate that this biosensor provides a direct, real-time measure of the extracellular concentration of glucose.     

Microelectrode Recording of Tissue Neural Oscillations for a Bionic Olfactory Biosensor

In olfactory research,neural oscillations exhibit excellent temporal regularity,which are functional and necessary at the physiological and cognitive levels.In this paper,we employed a bionic tissue biosensor which treats intact epithelium as sensing element to record the olfactory oscillations extracellularly.After being stimulated by odorant of butanedione,the olfactory receptor neurons generated different kinds of oscillations,which can be described as pulse firing oscillation,transient firing oscillation,superposed firing oscillation,and sustained firing oscillation,according to their temporal appearances respectively.With a time-frequency analysis of sonogram,the oscillations also demonstrated different frequency properties,such as δ,θ,α,β and γ oscillations.The results suggest that the bionic biosensor cooperated with sonogram analysis can well improve the investigation of olfactory oscillations,and provide a novel model for artificial olfaction sensor design.     

Cardiovascular Effects of Implanted Acrylic Bone Cement

A pilot study has shown that there is usually but not invariably a fall in systemic arterial blood pressure within 90 seconds of implanting acrylic cement into the femoral shaft during hip arthroplasty. There is usually no change in arterial blood pressure on implanting acrylic cement into the acetabulum. The observed hypotension may be due to absorption of monomer or additives into the circulation, but the role of other factors needs investigation.     

Thermal Memory in Self-Assembled Collagen Fibril Networks

Collagen fibrils form extracellular networks that regulate cell functions and provide mechanical strength to tissues. Collagen fibrillogenesis is an entropy-driven process promoted by warming and reversed by cooling. Here, we investigate the influence of noncovalent interactions mediated by the collagen triple helix on fibril stability. We measure the kinetics of cold-induced disassembly of fibrils formed from purified collagen I using turbimetry, probe the fibril morphology by atomic force microscopy, and measure the network connectivity by confocal microscopy and rheometry. We demonstrate that collagen fibrils disassemble by subunit release from their sides as well as their ends, with complex kinetics involving an initial fast release followed by a slow release. Surprisingly, the fibrils are gradually stabilized over time, leading to thermal memory. This dynamic stabilization may reflect structural plasticity of the collagen fibrils arising from their complex structure. In addition, we propose that the polymeric nature of collagen monomers may lead to slow kinetics of subunit desorption from the fibril surface. Dynamic stabilization of fibrils may be relevant in the initial stages of collagen assembly during embryogenesis, fibrosis, and wound healing. Moreover, our results are relevant for tissue repair and drug delivery applications, where it is crucial to control fibril stability.     

Simultaneous Histological Preparation of Bone, Soft Tissue and Implanted Biomaterials for Light Microscopic Observations

Block specimens of formalin fixed bone, soft tissue and endosseous implanted biomaterials can be successfully embedded in polymethyl methacrylate by employing vacuum desiccation during the dehydration steps and refrigeration during the infiltration step. One-hundred-micrometer histological sections can be obtained from the cured polymethyl methacrylate blocks by cutting with a low concentration diamond wafering blade on a Buehler Isomet Circular Low Speed Saw using Buehler Isocut fluid. The sections can be readily stained and details of individual cells studied by light microscopy, thus allowing interpretation of the relationship between biomaterial and surrounding tissues. The advantage of this method is that it allows observation of the entire specimen in situ. The details of the procedure are presented.     

Transitory versus Persistent Effects of Connectivity in Environmentally Homogeneous Metacommunities

While the effect of habitat connectivity on local and regional diversity has been analysed in a number of studies, time-dependent dynamics in metacommunities have received comparatively little consideration. When local patches of a metacommunity are identical in environmental conditions but differ in initial community composition, dispersal among patches may result in homogenization of local communities. In a microcosm experiment with benthic ciliates, we tested the hypothesis that the effect of connectivity on diversity is time-dependent and only transitory, with the degree of connectivity affecting the time to homogenization but not the final outcome. Six microcosms were connected to a metacommunity with one of three levels of connectivity. The six patches differed in initial community composition but were identical in environmental conditions. We found a time-dependent and transitory effect of connectivity on local and regional richness and on local Shannon diversity, while Bray-Curtis dissimilarity and regional Shannon diversity were persistently affected by connectivity. Local richness increased and regional richness decreased with connectivity during the initial phase of the experiment but soon converged to similar values in all three connectivity treatments. Local Shannon diversity was unimodally related to time, with maximum diversity reached sooner with high than with medium or low connectivity. Eventually, however, local diversity converged to similar values irrespective of connectivity. At the regional scale, Shannon diversity was persistently lower with high than with low connectivity. While initial differences in community composition vanished with medium and high connectivity, they were maintained with low connectivity resulting in persistently high beta and regional diversity. The effect of connectivity on ciliate community composition translated down to the algal resource, as stronger dominance of the superior competitor with high and medium connectivity resulted in stronger depletion of the resource.     

激光和生物组织的光热作用及临床应用

激光和生物组织的光热作用机理及在临床上的应用作了全面的论述,同时建立了一个定量描述光热作用的模型。讨论了光热作用中热产生,传导及热效应。     

Construction and Analyses of Human Large-Scale Tissue Specific Networks

Construction and analyses of tissue specific networks is crucial to unveil the function and organizational structure of biological systems. As a direct method to detect protein dynamics, human proteome-wide expression data provide an valuable resource to investigate the tissue specificity of proteins and interactions. By integrating protein expression data with large-scale interaction network, we constructed 30 tissue/cell specific networks in human and analyzed their properties and functions. Rather than the tissue specificity of proteins, we mainly focused on the tissue specificity of interactions to distill tissue specific networks. Through comparing our tissue specific networks with those inferred from gene expression data, we found our networks have larger scales and higher reliability. Furthermore, we investigated the similar extent of multiple tissue specific networks, which proved that tissues with similar functions tend to contain more common interactions. Finally, we found that the tissue specific networks differed from the static network in multiple topological properties. The proteins in tissue specific networks are interacting looser and the hubs play more important roles than those in the static network.