Polyurethane Enzyme Membranes for Chip Biosensors

Abstract

The coverage of electrochemical chip sensors based on silicon technology with a polyurethane enzyme membrane is described. After crosslinking of the surface by polyfunctional isocyanates the enzyme membrane shows good adhesion, complete retention of the enzyme molecules, and low diffusional resistance to both analytes and products. Using thin film noble metal electrodes and ion sensitive field effect transistors, glucose and urea sensors with good long term stability and short response time have been prepared.     

Exploring associations between micro-level models of innovation diffusion and emerging macro-level adoption patterns

A micro-level agent-based model of innovation diffusion was developed that explicitly combines (a) an individual’s perception of the advantages or relative utility derived from adoption, and (b) social influence from members of the individual’s social network. The micro-model was used to simulate macro-level diffusion patterns emerging from different configurations of micro-model parameters. Micro-level simulation results matched very closely the adoption patterns predicted by the widely-used Bass macro-level model (Bass, 1969 [1]). For a portion of the p−q$p-q$ domain, results from micro-simulations were consistent with aggregate-level adoption patterns reported in the literature. Induced Bass macro-level parameters p$p$ and q$q$ responded to changes in micro-parameters: (1) p$p$ increased with the number of innovators and with the rate at which innovators are introduced; (2) q$q$ increased with the probability of rewiring in small-world networks, as the characteristic path length decreases; and (3) an increase in the overall perceived utility of an innovation caused a corresponding increase in induced p$p$ and q$q$ values. Understanding micro to macro linkages can inform the design and assessment of marketing interventions on micro-variables–or processes related to them–to enhance adoption of future products or technologies.     

Optical Method for the in-situ Measurement of the pH-value During High Pressure Treatment of Foods

This contribution presents a novel optical method to determine the pH-value during the high pressure treatment of foods. Up to date an appropriate online measurement device does not exist. The present study makes use of a multivariate approach, using the optical properties of pH indicators. An indicator mix of 16 different pH-sensitive substances is applied. The calibration of the system is performed taking five different buffer substances (TRIS, CAPS, citric, phosphoric and acetic acid buffers), applying thermodynamical considerations, to calculate the pH-value at high pressure. The corresponding spectra of the indicator mix is measured and fed to a multivariate data model together with calculated pH values. Different chemometric models have been constructed to estimate the pH value based upon the spectrum of the indicator mix. The calibration device covers a pH range from 2 to 8. After calibration it was possible to determine the pH value at pressures up to 450 MPa with an accuracy of 0.02 pH units in 9 different test media.     

DEA production games

In this paper, linear production games are extended so that instead of assuming a linear production technology with fixed technological coefficients, the more general, non-parametric, DEA production technology is considered. Different organizations are assumed to possess their own technology and the cooperative game arises from the possibility of pooling their available inputs, collectively processing them and sharing the revenues. Two possibilities are considered: using a joint production technology that results from merging their respective technologies or each cooperating organization keeping its own technology. This gives rise to two different DEA production games, both of which are totally balanced and have a non-empty core. A simple way of computing a stable solution, using the optimal dual solution for the grand coalition, is presented. The full cooperation scenario clearly produces more benefits for the organizations involved although the implied technology sharing is not always possible. Examples of applications of the proposed approach are given.     

大豆渣中异黄酮的提取及抑菌活性

研究大豆豆渣中异黄酮提取的工艺条件及其抑菌活性。在单因素试验和L25(54)正交试验的基础上,确定正己烷料液比1∶8(g/mL)、乙醇混合提取大豆异黄酮的最佳工艺条件:乙醇浓度70%、料液比(g/mL)1∶12、提取温度65℃和提取时间2.5h。对大豆异黄酮的抑菌活性进行了研究,结果表明:大豆异黄酮对金黄色葡萄球菌、枯草芽孢杆菌、短小芽孢杆菌和红曲霉的生长均有明显的抑制作用,抑菌作用符合三次回归方程,对大肠杆菌和短乳杆菌没有显著影响。     

Ag负载WO3/TiO2光催化剂的合成及其催化性能

以钛酸丁酯、无水乙醇、钨酸铵为原料,采用溶胶-凝胶法合成了WO3/TiO2复合光催化剂;采用光还原技术制备了Ag负载WO3/TiO2光催化剂,借助X射线粉末衍射(XRD)和UV-Vis光谱等技术对样品的组成和光吸收性能进行了表征,并以罗丹明B为模型污染物考察样品的光催化活性。XRD分析表明,所得粉体均为锐钛矿型纳米TiO2,且与WO3复合后,纳米TiO2特征衍射峰宽化,强度降低;UV-Vis光谱分析表明,载银使得催化剂在400—700nm的可见光区域对光响应,且在紫外光区吸收显著增强,对光具有更高的利用率;以罗丹明B为降解物的光催化实验表明,WO3复合对纳米TiO2光催化活性有显著的影响,而载Ag后其光催化活性进一步提高,将该光催化剂用于炼油厂废水的处理,效果较好。     

挪威科技大学胶体与界面化学教学方法对我国物理化学课程教学的启发

胶体与界面化学是物理化学的一个重要分支。总结了挪威科技大学Johan Sjöblom教授在胶体与界面化学教学方面独特的教学理念与方法,对于提高我国物理化学教学质量及其教学改革具有借鉴和启迪作用。     

电感耦合等离子体质谱法检测氧化镓中杂质元素

建立了电感耦合等离子体质谱法(ICP-MS)测定氧化镓中杂质元素的检测方法,采用微波消解技术溶样,以5 ng/mL Rh为内标补偿校正镓基体的抑制效应,采用碰撞室技术(CCT)消除多元素分子离子的干扰.方法的检出限为0.10～1.0 ng/mL,加标回收率在85%～110%之间,RSD为0.6%～7.1%.该方法能满足99.95%～99.995%氧化镓中杂质元素的分析要求.     

安徽繁昌柯家冲窑青白瓷釉化学组成及其制釉工艺来源研究

为了解繁昌柯家冲窑青白瓷釉化学组成特征及其演变过程,并探索我国南方早期青白釉的工艺技术来源,本文运用能量色散X射线荧光光谱法(EDXRF)分析了柯家冲窑五代至北宋中期不同阶段青白瓷釉的化学组成,并将分析结果与同时期北方定窑白瓷釉及南方越窑青瓷釉化学组成进行了综合对比研究。结果显示,繁昌柯家冲窑青白釉化学组成在北宋中期时发生了明显变化,其中尤以SiO₂含量的下降和CaO含量的上升最为明显,着色元素Fe,Mn,Ti的氧化物含量自五代时期至北宋中期变化幅度很小,繁昌柯家冲窑青白釉釉色由偏白向偏青转变的原因可能与该窑瓷器胎色的不断加深有关。此外,主成分分析及具有相似功能特性的元素组合对比分析结果显示,繁昌柯家冲窑青白瓷釉的化学组成与北方定窑白瓷釉较为接近,其釉料配方工艺可能来源于同时期我国北方地区以定窑为代表的白瓷窑场。本文研究结果对了解我国早期青白瓷釉的化学组成特征及晚唐五代时期南、北方制瓷工艺技术交流问题等有重要学术价值。     

微生物电化学污水处理技术的优势与挑战

微生物电化学技术（Microbial Electrochemical Technology, MET）最为一种新型水处理工艺,因其具有污染物同步去除和能源化的特点受到广泛重视. 近年来微生物电化学系统（Microbial Electrochemical System, MES）的研究者在其电子传递机理、功能菌群分析、系统功能拓展、低成本材料开发和大型系统构建等方面取得大量进展. 然而该技术作为污水处理工艺的可行性却始终存在争议. 本文从应用角度将MET工艺与现有厌氧、好氧工艺进行对比,分析各工艺在有机物降解和能量回收方面的特点,有助于找到MET工艺在水处理领域中的适宜定位. 相对厌氧与好氧工艺,MET工艺具有低污泥产率,运行过程能量自给以及电流加速污染物去除等优势特征,但在推进MET工艺的实用化进程中仍需进一步简化其系统结构、降低构筑成本、提高运行稳定性,并应基于MET的运行特征确定其适宜的应用范围以发挥MET工艺的技术优势.