Controlled immobilization of peptide nanotube-templated metallic wires on Au surfaces

Peptide nanotubes were immobilized on Au substrates functionalized with self-assembled monolayers of 4-mercaptobenzoic acid in a pH 6 citric acid solution via hydrogen bonds between the peptide nanotubes and the monolayers. Subsequently, the immobilized nanotubes were metallized by nickel via the electroless coating process. Received 30 November 2000     

水包水型阳离子乳液絮凝剂的合成及其应用

以丙烯酰胺(AM)和丙烯酰氧乙基三甲基氯化铵(DAC)为主要单体在聚乙二醇20000(PEG 20000)溶液中进行自由基共聚合成了固含量高、絮凝效果好且速溶的水包水型阳离子聚丙烯酰胺乳液。在充氮气30 min,60℃下反应5 h,AM和DAC质量百分数分别为20%和0.5%的最优条件下,合成的阳离子絮凝剂(CPF)乳液对生化污水上清液透光率达到95%。红外光谱分析表明,聚合物分子结构中含有AM和DAC链节。     

铜中毒对SD大鼠肝的影响研究

将36只雄性大鼠80~100 g随机分为3组,分别喂以对照日粮(Cu质量分数13.15mg/kg)和高铜日粮(Cu质量分数650、850 mg/kg),实验期为9周,进行了铜中毒对大鼠肝脏影响的病理学研究。结果表明,与对照组比较,高铜Ⅰ、Ⅱ组大鼠肝脏出现不同程度的病理损害;大鼠肝脏脏器系数有增高趋势,但差异无显著(P0.05)。同时,乳酸脱氢酶、谷草转氨酶活性显著升高(P0.01),血清铜含量上升,SOD含量下降。提示日粮铜质量分数650~850 mg/kg即可引起大鼠肝脏的病理损伤,功能降低。     

Vectorial photoinduced electron transfer in phospholipid vesicles and LB bilayers

Summary Photoinduced electron transfer (PET) was studied in phospholipid vesicles and in Langmuir-Blodgett bilayers in the attempt to produce a model for electron transfer processes in biological media. Spatial organization of the reaction centers in lipid membranes needs to be controlled in order to provide high efficiency of light-to-chemical energy conversion. We designed a phospholipid system where the donor is localized in the inner bilayer whereas the acceptor is at the polar groups-water interface. We used dipalmitoylphosphatidic acid vesicles containing low molar fractions of dipalmitoylphosphatidylcholine with pyrene (donor) bound to one of the alkyl chains. Methylviologen (acceptor) was added to the external aqueous phase; upon photoexcitation of the donor we observed the electron transfer to take place in a unidirectional manner from the inside of the bilayer to the interface. Information about the location of the donor was obtained studying the photophysical properties of the pyrene chromophore in vesicles and in LB layers. The photoinduced electron transfer reaction was evidenced by quenching of pyrene fluorescence in the presence of increasing concentrations of acceptor, the process was studied both with steady-state and time-resolved fluorescence emission. Fluorescence intensity was found to decrease with increasing concentration of methylviologen, similar results were obtained for vesicles and LB layers of analog composition immersed in a methylviologen solution. Lifetimes of the excited species were found to be of the same order of magnitude in vesicle and LB-layer systems. Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994.     

近红外光谱无创生化检测中不定光程对模型精度的影响研究

利用近红外血流容积光谱相减方法无创伤定量分析人体血液生化成分时,获得的在体血液光谱对应的样品光程是不确定的。为研究样品间的光程差异对定标模型预测精度的影响,配制了30份模拟血清样品,利用可变光程样品池,采用傅里叶光谱仪分别测量了相同光程和不定光程两组样品的近红外光谱。以分析血清白蛋白成分为例,对两组样品的定标模型精度进行比较,结果显示不定光程组的模型精度与相同光程组的模型精度相比明显下降,交叉检验标准差(RMSECV)由110.0mg/dL增大至156.0mg/dL。采用多元散射校正算法对上述光谱数据校正后,RMSECV降低至98.1mg/dL。对比分析处理前后两组模型的精度,证实了采用适当的预处理方法能够有效校正不定光程引起的光谱误差,提高模型预测精度。     

近红外无创生化检测中不同光程的光谱校正模型研究

近红外无创生化检测中采用不同血流容积光谱相减的方法理论上能够消除人体组织产生的强背景干扰,但人体光谱相减后得到的血液光谱的光程是未知的,这给校正模型的建立带来了困难。通过设计模拟实验并采用正交信号校正的方法对光程信息进行校正,提高不同光程的光谱建立校正模型的预测精度。分别建立了光程校正前后的模型,模型的交叉验证标准偏差从90.17mg.dL-1下降到31.62mg.dL-1,相关系数从0.978 7提高到0.996 8。实验结果表明,采用正交信号校正的方法能够有效抑制光程信息的干扰,提高模型的预测精度,这为不同血流容积光谱相减法的实际应用提供了基础。     

平面光波导用于实时测试生化反应新方法的研究

在分析经典消逝波光波导生化传感器的基础上,为寻找性能更佳的传感器,探讨用更为直观的截止特性来进行生化传感。分别对三层及四层平板波导进行了研究,指出了作为基于截止特性的生化传感器三层波导结构存在的局限性。在理论上研究了可以在四层波导中使用变折射率材料来进行基于截止特性的生化传感,并给出了由空气隙、极化聚合物、高折射率薄膜、待测物组成的传感器结构示意图。用数值分析的方法绘出了此装置的灵敏度与高折射率薄膜厚度的关系曲线,并将它同经典消逝波光波导生化传感器灵敏度与薄膜厚度关系图进行了比较。结果表明,这种新型传感器理论上可以在较厚的薄膜结构中达到很高的灵敏度。     

Biophysical model for high-throughput tumor and epithelial cell co-culture in complex biochemical microenvironments

The in vivo tumor microenvironment is a complex niche that includes heterogeneous physical structures,unique biochemical gradients and multiple cell interactions.Its high-fidelity in vitro reconstruction is of fundamental importance to improve current understandings of cell behavior,efficacy predictions and drug safety.In this study,we have developed a high-throughput biochip with hundreds of composite extracellular matrix(ECM)microchambers to co-culture invasive breast cancer cells(MDA-MB-231-RFP)and normal breast epithelial cells(MCF-10 A-GFP).The composite ECM is composed of type I collagen and Matrigel which provides a heterogeneous microenvironment that is similar to that of in vivo cell growth.Additionally,the growth factors and drug gradients that involve human epidermal growth factor(EGF),discoidin domain receptor 1(DDR1)inhibitor 7 rh and matrix metalloproteinase inhibitor batimastat allow for the mimicking of the complex in vivo biochemical microenvironment to investigate their effect on the spatial-temporal dynamics of cell growth.Our results demonstrate that the MDA-MB-231-RFP cells and MCF-10 A-GFP cells exhibit different spatial proliferation behaviors under the combination of growth factors and drugs.Basing on the experimental data,we have also developed a cellular automata(CA)model that incorporated drug diffusion to describe the experimental phenomenon,as well as employed Shannon entropy(SE)to explore the effect of the drug diffusion coefficient on the spatial-temporal dynamics of cell growth.The results indicate that the uniform cell growth is related to the drug diffusion coefficient,which reveals that the pore size of the ECM plays a key role in the formation of complex biochemical gradients.Therefore,our integrated,biomimetic and high-throughput co-culture platforms,as well as the computational model can be used as an effective tool for investigating cancer pathogenesis and drug development.     

基于回声状态网络的BOD在线软测量模型

针对污水处理过程的BOD建模问题,提出了一种基于回声状态网络的BOD在线软测量方法;基于梯度下降规则对回声状态网络的在线学习算法进行了研究;为保证学习算法的收敛性,基于Lyapunov理论对学习率范围进行了确定;实验表明,基于回声状态网络的在线BOD预测方法较常规神经网络预测精度提高约两个数量级,模型的适应性也大幅提高。     

快速生化需氧量微生物传感器的应用

采用混合菌BODseed制备微生物传感器快速监测生化需氧量（BOD）,研究了矫正溶液选择、样品自降解及恒温装置对测量准确度的影响。 结果表明,采用葡萄糖 谷氨酸矫正溶液测得污水处理厂污水结果较BOD5方法偏低50%以上,而以污水本身制作矫正曲线取得了与BOD5一致的测试结果;样品在保存6 h后有机物自降解会使测量结果偏低40%;快速BOD在线监测时不仅需要对微生物传感器恒温,同时也需要对样品及缓冲溶液恒温,这有利于样品快速接近缓冲溶液温度,减少空气饱和时间,从而提高监测效率,提升测试准确度。