荧光原位杂交技术在活性污泥菌群识别中的研究进展

荧光原位杂交技术(FISH)广泛地应用于分析环境微生物的群落组成,能够同时对微生物进行定性、定量分析,并确定微生物群落空间分布情况.本文阐述了FISH法应用于活性污泥处理系统的重要作用,综述了FISH法在活性污泥及生物膜微生物菌群的组成、结构与功能的研究和应用,同时讨论了其在应用中存在的不足,并在此基础上总结了一系列可...     

原位FTIR在研究催化剂积炭失活中的应用

本文综述了原位傅立叶变换红外光谱(FTIR)在研究石油化工催化反应中积炭现象的进展,介绍了运用原位FTIR在表征催化异构化反应、催化还原反应、催化裂化反应过程中催化剂积炭的结果,总结了对固体酸催化剂和双官能贵金属-酸催化剂上积炭形式的研究,讨论了不同温度下的积炭形成的过程。结合本课题组对正庚烷催化裂解反应的初步研究结果,提出原位FTIR重点问题是峰的识别与归属,其应用可以拓展到更多催化反应的机理和历程的研究。     

In Situ Synthesis and Copolymerization of Oligonucleotides on Conducting Polymers

 Two strategies of DNA biochip construction on conducting polymers are investigated. The first involves a direct electro-copolymerization of pyrrole–oligonucleotides (oligonucleotides tethered to a pyrrole group) with the pyrrole leading to a polypyrrole film bearing the oligonucleotides. Successive copolymerizations allow the transformation of a microelectrode array into a DNA array. The second methodology involves a direct in situ synthesis of oligonucleotides on a conducting polymer used as an organic electrode. In this way a 5′ electrolabile protecting group, p-nitrobenzoyl, was used. In order to construct short oligonucleotide sequences, the other protecting groups of the bases have also to be modified. Preliminary results based on this technology are shown. Received July 28, 1998. Revision October 19, 1998.     

The Application and Research of Dispersing In Situ Nano-SiO2 in Polyether Demulsifier TA1031

In order to enlarge the application range of nanomaterial and improve the demulsification performance of macromolecule polyether demulsifier, the nano-SiO₂ was dispersed in situ in polyether demulsifier TA1031 to form a new high efficiency demulsifier. The new demulsifier was analyzed by FTIR, SEM, rotational viscometer, and interfacial tension meter. The result showed that dispersing nano-SiO₂ in crude oil demulsifier would greatly improve the demulsification performance of the original demulsifier. When the ratio of silicon dioxide and TA1031 is 1:10 (mass ratio), the demulsification performance of the new demulsifier was the best, and the dehydration rate of emulsion increased about by 20%. Also the time of demulification and dehydration would be greatly shortened, and the demusification mechanism was preliminary analyzed.     

Application of In Situ Product Crystallization and Related Techniques in Biocatalytic Processes

This Minireview highlights the application of crystallization as a very powerful in situ product removal (ISPR) technique in biocatalytic process design. Special emphasis is placed on its use for in situ product crystallization (ISPC) to overcome unfavorable thermodynamic reaction equilibria, inhibition, and undesired reactions. The combination of these unit operations requires an interdisciplinary perspective to find a holistic solution for the underlying bioprocess intensification approach. Representative examples of successful integrated process options are selected, presented, and assessed regarding their overall productivity and applicability. In addition, parallels to the use of adsorption as a very similar technique are drawn and similarities discussed.     

Characterization and Optimization of Injectable In Situ Crosslinked Chitosan-Genipin Hydrogels

In recent years, there has been an increased interest in injectable, in situ crosslinking hydrogels due to their minimally invasive application and ability to conform to their environment. Current in situ crosslinking chitosan hydrogels are either mechanically robust with poor biocompatibility and limited biodegradation due to toxic crosslinking agents or the hydrogels are mechanically weak and undergo biodegradation too rapidly due to insufficient crosslinking. Herein, the authors developed and characterized a thermally-driven, injectable chitosan-genipin hydrogel capable of in situ crosslinking at 37 °C that is mechanically robust, biodegradable, and maintain high biocompatibility. The natural crosslinker genipin is utilized as a thermally-driven, non-toxic crosslinking agent. The chitosan-genipin hydrogel's crosslinking kinetics, injectability, viscoelasticity, swelling and pH response, and biocompatibility against human keratinocyte cells are characterized. The developed chitosan-genipin hydrogels are successfully crosslinked at 37 °C, demonstrating temperature sensitivity. The hydrogels maintained a high percentage of swelling over several weeks before degrading in biologically relevant environments, demonstrating mechanical stability while remaining biodegradable. Long-term cell viability studies demonstrated that chitosan-genipin hydrogels have excellent biocompatibility over 7 days, including during the hydrogel crosslinking phase. Overall, these findings support the development of an injectable, in situ crosslinking chitosan-genipin hydrogel for minimally invasive biomedical applications.     

Toehold‐initiated Rolling Circle Amplification for Visualizing Individual MicroRNAs In Situ in Single Cells

The ability to quantitate and visualize microRNAs (miRNAs) in situ in single cells would greatly facilitate the elucidation of miRNA‐mediated regulatory circuits and their disease associations. A toehold‐initiated strand‐displacement process was used to initiate rolling circle amplification of specific miRNAs, an approach that achieves both stringent recognition and in situ amplification of the target miRNA. This assay, termed toehold‐initiated rolling circle amplification (TIRCA), can be utilized to identify miRNAs at physiological temperature with high specificity and to visualize individual miRNAs in situ in single cells within 3 h. TIRCA is a competitive candidate technique for in situ miRNA imaging and may help us to understand the role of miRNAs in cellular processes and human diseases in more detail.     

邻氨基酚与邻苯二胺共聚的原位紫外-可见光谱电化学研究

运用循环伏安法(CV)和原位紫外-可见光谱电化学法分别研究了邻氨基酚(OAP)和邻苯二胺(OPD)在1 mol/L HCl溶液中单独聚合及二者共聚的电化学过程。OAP和OPD单独聚合及二者共聚时呈现出的不同电化学行为表明OAP和OPD发生了共聚反应。原位紫外-可见光谱研究表明,在共聚过程中,OAP和OPD首先分别被氧化生成其相应的阳离子自由基,然后,OAP和OPD的阳离子自由基与溶液中的OPD和OAP单体或其阳离子自由基发生交互反应生成类苯胺和类吩嗪结构的二聚物/低聚物中间体,生成的中间体继续发生耦合反应生成OAP和OPD的共聚物,呈现出两个波长分别位于477 nm和419 nm处的吸收峰。并用傅立叶变换红外光谱(FT-IR)表征了共聚物的生成。进一步研究发现,OAP和OPD的共聚过程与溶液中OAP和OPD单体的浓度比有关。     

金属铈表面氧化还原过程的原位拉曼光谱研究

采用显微拉曼光谱仪原位监测了金属铈表面的氧化和还原过程。2132和2239 cm-1处尖锐Ce3+电子散射峰的出现及462 cm-1处CeO2特征振动峰的消失表明,在高温、高真空条件下金属铈表层的CeO2已转变为Ce2O3。根据1503,1796和2113 cm-1处多个Ce3+电子散射峰及CeO2特征振动峰强度随时间的变化关系,可将金属Ce在空气中的氧化过程分为3个阶段,首先不同价态铈氧物层均快速增长,随后外层的CeO2陷入停顿,含Ce3+的铈氧物层继续增长,最后随着3603 cm-1处OH-的出现,CeO2再次快速增长。     

原位漫反射红外光谱技术用于气固催化反应机理的研究

漫反射傅立叶变换红外光谱技术是一种对固体粉末样品进行直接测量的光谱方法,是近年来发展起来的一项较理想的原位表征技术。原位漫反射红外技术由于可直接对催化剂表面的吸附态物种给出红外信号,可方便地跟踪鉴定反应中间态和产物,从而为催化反应体系反应机理的考察给出直接的证据。本文对于原位漫反射红外技术用于低温水煤气变换反应和水汽逆变换反应、醇类的水蒸汽重整、含CO₂的合成气制取甲醇、低碳烃制合成气、CO催化氧化以及其他烃类和含氧化合物的氧化等方面进行了综述,认为该技术可很好地剖析气固相催化反应机理。     

二苯胺与邻氨基酚共聚的原位紫外-可见光谱电化学研究

运用循环伏安法(CV)和原位紫外-可见光谱电化学法研究了二苯胺(DPA)和邻氨基酚(OAP)在4mol/L H2SO4中单独聚合及二者共聚的电化学过程。DPA和OAP单独聚合及二者共聚时不同的电化学行为表明DPA和OAP之间发生了共聚作用。原位紫外-可见光谱研究表明,在DPA与OAP的共聚过程中,DPA与OAP首先被氧化生成阳离子自由基,然后,两者的阳离子自由基与溶液中的DPA和OAP单体或其自由基发生交互反应产生混合二聚物中间体,其吸收峰位于508 nm处。进一步研究发现,DPA和OAP的共聚过程与溶液中各单体的浓度比有关。     

微波辅助4-十二烷氧基苄胺保护的憎水性纳米金原位还原合成

利用新型表面活性剂4-十二烷氧基苄胺(C₁₂OBA)构成的C₁₂OBA/正庚烷/正丁醇/HAuCl₄/NaOH(aq.) W/O型微乳液作为微反应器, 通过微波辐射加热的正丁醇原位还原法制备了C₁₂OBA包裹的憎水性金纳米粒子, 并通过紫外可见光谱(UV-vis)、透射电镜(TEM)、X射线衍射(XRD)、红外光谱(FT-IR)和接触角(CA)等分别进行了表征和分析. 结果显示, C₁₂OBA既可参与形成稳定的W/O型微乳液, 又可作为金粒子的良好保护剂. 微乳液内核中碱度的增加能增强位于膜相的正丁醇分子的还原能力. 在固定氯金酸用量时, C₁₂OBA/金的物质的量比增加有利于获得小尺寸、高单分散性的憎水性纳米金颗粒, 而体系的极性增加则导致金粒子的尺寸增大、单分散性下降. 通过本实验方法可方便快速地合成尺寸约为5 nm的具有高度单分散的憎水性金纳米粒子.     

Exfoliation and Noncovalent Functionalization of Graphene Surface with Poly-N-Vinyl-2-Pyrrolidone by In Situ Polymerization

Heteroatom functionalization on a graphene surface can endow the physical and structural properties of graphene. Here, a one-step in situ polymerization method was used for the noncovalent functionalization of a graphene surface with poly-N-vinyl-2-pyrrolidone (PNVP) and the exfoliation of graphite into graphene sheets. The obtained graphene/poly-N-vinyl pyrrolidone (GPNVP) composite was thoroughly characterized. The surface morphology of GPNVP was observed using field emission scanning electron microscopy and high-resolution transmission electron microscopy. Raman spectroscopy and X-ray diffraction studies were carried out to check for the exfoliation of graphite into graphene sheets. Thermogravimetric analysis was performed to calculate the amount of PNVP on the graphene surface in the GPNVP composite. The successful formation of the GPNVP composite and functionalization of the graphene surface was confirmed by various studies. The cyclic voltammetry measurement at different scan rates (5–500 mV/s) and electrochemical impedance spectroscopy study of the GPNVP composite were performed in the typical three-electrode system. The GPNVP composite has excellent rate capability with the capacitive property. This study demonstrates the one-pot preparation of exfoliation and functionalization of a graphene surface with the heterocyclic polymer PNVP; the resulting GPNVP composite will be an ideal candidate for various electrochemical applications.     

In Situ Synthesis of Manganese Oxide as an Oxygen-Evolving Catalyst: A New Strategy

All studies on oxygen-evolution reaction by Mn oxides in the presence of cerium(IV) ammonium nitrate (CAN) have been so far carried out by synthesizing Mn oxides in the first step. And then, followed by the investigation of the Mn oxides in the presence of oxidants for oxygen-evolution reaction (OER). This paper presents a case study of a new and promising strategy for in situ catalyst synthesis by the adding Mn^II to either CAN or KMnO₄/CAN solution, resulting in the formation of Mn-based catalysts for OER. The catalysts were characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. Both compounds contained nano-sized particles that catalyzed OER in the presence of CAN. The turnover frequencies for both catalysts were 0.02 (mmol /mol_Mn⋅s).     

丙烯腈与二乙烯苯原位聚合制备强极性高聚物涂层毛细管柱

以丙烯腈为单体，二乙烯苯为交联剂，采用原位聚合法制备出了强极性的有机高聚物多孔层开管柱－ＯＰＰＬＯＴ－Ａ型柱。对影响制备的因素如致孔剂的选择，反应温度与反应时间，引发剂的选择及浓度等进行了讨论。应用扫描电镜和红外光谱对形成的高聚物固定相的结构进行了表征。实验表明该柱对腈、醛类等化合物有好的分离性能。     

原位氧化聚合制备导电PAn-PC和PAn-SIR复合膜

以聚碳酸酯（PC）和硅橡胶（SIR）为基体浸泡于苯胺（An）的盐酸溶液中,然后经氧化剂（NH4）2S208（APS）或FeCl3在基体中原位氧化聚合,制备导电聚苯胺（PAn）复合材料PAn-PC和PAn-SIR。研究了聚合反应的工艺条件对复合材料导电性能的影响,确定了合适的制备条件。采用扫描电镜（SEM）及荧光光谱对复合膜进行表征。     

苯胺与邻-氨基苯磺酸电化学共聚的原位紫外-可见光谱研究

运用原位紫外-可见吸收光谱法和红外光谱法分别研究了苯胺(AN)和邻-氨基苯磺酸(ABSA)在0.1mol/L HCIO4溶液中的单独聚合及共聚过程.结果表明,在AN和ABSA的共聚过程中,ABSA首先被氧化生成其阳离子自由基,然后ABSA阳离子自由基与继而生成的AN阳离子自由基和溶液中的AN及ABSA单体发生交互反应,...     

A Pyrene Derivative for Hg2+‐Selective Fluorescent Sensing and Its Application in In Vivo Imaging

An Hg²⁺‐selective fluorescent sensor ( 1 ) bearing pyrene as a fluorophore was synthesized. A sandwich‐stacking binding mode was formed during the binding process, which increased the excimer fluorescence 22‐fold at 490 nm. Compound 1 was successfully applied in in vivo imaging to trace the enrichment and distribution of mercury in the nervous system, digestive system, and reproductive system of Caenorhabditis elegans, as well as the organs of zebrafish.     

钒氧化物电极材料晶格呼吸现象原位探测及其反应机制研究

作为锂离子电池正极材料,层状钒氧化物具有优异的物理特性和良好的储锂性能,因此被广泛研究与应用于工业生产与日常生活的各个方面.然而,在脱嵌锂的过程中,V₂O₅凝胶等层状钒氧化物的层状结构存在“晶格呼吸”现象.这种现象导致了电极材料的钝化,并进一步导致电池容量快速衰减.采用了原位X射线衍射（XRD）来研究一种层状钒氧化物（VO_x）在充放电过程中的“晶格呼吸”现象,揭示了其独特的相变过程.在充放电过程中,原位XRD对应的二维衍射图显示出三个不同的阶段,分别对应三个固溶反应.放电过程中,三个阶段的衍射峰都向高角度偏移,表明在锂离子嵌入过程中,VO_x的层间距存在持续收缩过程.（001）层间距大小随充放电过程的变化图进一步证明了这三个过程的不连续性.这些发现揭示了这类材料在电极反应过程中的晶体结构变化规律以及造成其容量衰减的原因.