纳米TiN修饰平面微电极阵列在神经信息双模检测中的应用

采用氮化钛(TiN)修饰平面微电极阵列(pMEA),对其性能进行改进,开展了离体神经电生理和神经递质电化学的检测研究。采用磁控溅射法在实验室自制微电极阵列上修饰具有纳米结构的TiN材料,修饰后的微电极阻抗降低近一个数量级,背景噪声基线降至±6μV,信噪比是修饰前的1.7倍。在SD大鼠离体脑片神经电生理信号检测中,信噪比可达10∶1,能分离提取±12μV的微弱信号。神经递质多巴胺电化学信号检测下限达50 nmol/L(信噪比2∶1),浓度在0.05~100μmol/L内与电流响应的线性相关系数为0.998。实验结果表明,在微电极表面修饰纳米TiN,降低了微电极阻抗,提高了信噪比,实现了对神经信息微弱信号的检测。     

基于双模检测仪器的大鼠神经放电和神经化学信号同步检测研究

研制了一种可同步检测神经电生理和化学信号的双模检测仪,并应用此仪器开展了双模同步检测实验。此仪器具有0.3μV电压分辨率的64通道神经电生理检测功能、pA级电流精度的4通道电化学检测功能,具备动作电位分离分类、计时电流法、循环伏安法等常用的检测功能,并且能实现对双模神经信号的同步观测和分析。在采用此仪器开展的单模实验中,完整地检测到了64通道的模拟神经信号,结合微电极阵列获得了信噪比( S/N)为6的神经动作电位发放;采用循环伏安法,获得了铁氰化钾在溶液浓度0.1~10 mmol/L范围内与电流响应的线性相关系数为0.9889;同时,采用计时电流法获得了抗坏血酸在溶液浓度10~800μmol/L 范围内与电流响应的线性相关系数为0.9841。结合大鼠脑缺血模型开展了双模检测实验,在该模型中成功地同步检测到了神经动作电位发放和抗坏血酸浓度变化引起的电流变化,并发现大鼠大脑初级感觉皮层抗坏血酸浓度与动作电位发放呈一定负相关关系。     

16通道神经信息双模检测分析仪的研制与应用

研制了一种可检测分析神经电生理信号和递质化学信号的16通道双模检测分析仪.仪器山硬件和软件系统组成,其电流和电压分辨率分别为10 pA和0.6 μV,具备实时峰电位分离,数字IIR滤波,计时电流法,循环伏安法等常用电生理和电化学检测分析方法.为验证仪器的性能分别进行了电生理信号和电化学信号的检测实验.在SD大鼠脑部电生...     

聚精氨酸修饰玻碳电极上多巴胺的电化学特性及其检测

用循环伏安法制备了聚精氨酸修饰玻碳电极,研究了神经递质多巴胺在该聚合物薄膜修饰电极上的电化学行为及其检测。在pH7.0的磷酸盐缓冲溶液中,多巴胺在聚精氨酸修饰电极上于0.19V和0.16V处出现一对灵敏、可逆的氧化还原峰。在最佳测试条件下,氧化峰电流与多巴胺的浓度在3.0×10-7~8.0×10-4mol/L范围内呈良好的线性关系,线性回归方程为Ipa(μA)=86.063C(mmol/L) 20.183,相关系数r=0.9993,最低检测限(3σ)5.0×10-8mol/L。用于多巴胺针剂含量的测定,结果满意。     

采用纳米金修饰的方法再生碳纤维微电极

采用电沉积法将纳米金(GNP)修饰到毒化的碳纤维电极表面制得再生碳纤维电极,用循环伏安法(CV)和差分脉冲伏安法(DPV)对神经递质在该再生电极上的电化学行为进行了研究。实验结果表明,在20 mmol/L,pH7.2的Tris-HCl缓冲溶液中,再生电极对多巴胺、去甲肾上腺素等神经递质具有良好的电化学响应。对纳米金的电沉积时间进行了优化,在优化条件下,采用DPV法,DA的氧化峰电流与其浓度在5×10~(-7)~1×10~(-4)mol/L范围内呈良好的线性关系,线性相关系数(R~2)为0.9979,检出限为5×10~(-7)mol/L。     

银掺杂聚L-天冬氨酸修饰电极的制备及对多巴胺的测定

利用循环伏安法将银与L-天冬氨酸聚合修饰在玻碳电极表面,制成银掺杂聚L-天冬氨酸修饰电极,研究了多巴胺在此电极上的电化学行为,建立了循环伏安法测定多巴胺的新方法.在磷酸盐缓冲溶液(PBS, pH 7.0)中,扫描速率为50 mV/s时,多巴胺在修饰电极上产生一对氧化还原峰,Epa=0.191 V,Epc=0.161 V.用循环伏安法进行测定时,峰电流与多巴胺浓度分别在3.0×10-7 ～1.0×10-5 mol/L和1.0×10-5 ～5.0×10-4 mol/L内呈良好的线性关系; 检出限为5.0×10-8 mol/L.用于药物和尿样中多巴胺的测定,结果满意.     

电化学活化碳纤维微电极和脑神经递质及抗坏血酸在体测定

本文采用一种简单电化学方法,即恒电流法处理自制碳纤维电极,在脑神经递质测定中显示了很高的灵敏度和分辨能力.活化后的电极对多巴胺的检测限达5×10^-8mol.dm^-3,对多巴胺和抗坏血酸的伏安峰分离达170mV.作者使用该电极,采用半微分伏安法测定了活体大鼠脑内抗坏血酸,3,4-二羟苯乙酸和5-羟吲哚乙酸的浓度分别为1.7×10^-4,2.1×10^-5和 3.3×10^-6mol·dm^-3.本文对电极的制作,活化条件,伏安峰判别,在体药物实验和电极活化机理等进行了研究和探讨.     

多巴胺有序介孔硅表面分子印迹传感器的研制

以多巴胺(DA)为模板,氨基修饰的介孔硅为载体,制得对多巴胺具有特异选择性的表面分子印迹聚合物(MIP)。将所得的MIP制成碳糊电极,用循环伏安法对多巴胺进行检测。在优化实验条件下,传感器的氧化峰电流与多巴胺浓度在1.0×10-7～2.0×10-6mol/L和2.0×10-6～1.0×10-4mol/L范围内呈良好的线性关系,相关系数分别为0.992 5和0.996 9,检出限为1.3×10-9mol/L。该传感器对DA具有较高的灵敏度和选择性,将其用于实际样品检测,结果满意。     

CuNi/β-环糊精/还原氧化石墨烯修饰电极电化学检测多巴胺

建立了一种循环伏安法制备CuNi/β-环糊精/还原氧化石墨烯修饰玻碳电极(CuNi/β-CD/ERGO/GCE)的方法。通过多巴胺在该修饰电极上的电化学行为发现,该电化学传感器实现了快速、灵敏的测定多巴胺。该传感器用差分脉冲伏安法(DPV)测定多巴胺时,其电化学响应电流与多巴胺浓度在0.01~20μmol/L之间呈线性关系,检测限为8 nmol/L。该传感器用于尿液样品中的多巴胺检测,回收率在95.6%~107.2%之间。     

聚L-组氨酸修饰碳黑微电极的制备及多巴胺的测定

用电聚合法制备了聚L-组氨酸修饰碳黑微电极,研究了多巴胺在该修饰电极上的电化学行为。实验表明:该修饰电极对神经递质多巴胺的电化学氧化有显著的催化作用,采用二次导数线性扫描伏安法对多巴胺进行测定,在pH 7.0的磷酸盐缓冲溶液中,多巴胺在0.15 V处产生一灵敏的氧化峰,多巴胺的氧化峰电流与浓度在4.0×10-8~1.0×10-4mol/L范围内呈线性关系,检出限(3σ)为1.0×10-8mol/L。该聚合物修饰电极具有良好的选择性,能有效地排除抗坏血酸对测定的影响,用于人工合成样品的分析。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.