Facial Preparation of Magnetic Lipase as Efficient Biocatalyst to Resolute Esters Enantioselectively

Magnetic lipase was prepared by a facial and cost-effective method. Lipase from Pseudomonase cepacia was covalently linked to Fe₃O₄ nanoparticles, which were produced by co-precipitating Fe²⁺ and Fe³⁺ ions in ammonia solution and subsequent coating with 3,4-dihydroxylaldehyde. Magnetic Fe₃O₄ nanoparticles modified with 3,4-dihydroxylaldehyde bonded lipase efficiently(47 mg/g). The resulting magnetic-lipase is active(0.68 μmol·min^-1·mg^-1) and enantioselective(e.e. of the product >98%) in the hydrolysis of racemic 1-phenylethyl acetate. Furthermore, as a heterogeneous catalyst, the magnetic-lipase can be magnetically recycled, and a retained activity of 48% was obtained even after 6 cycles.     

Preparation of Ag-MnFe2O4-bentonite Magnetic Composite for Pb(Ⅱ)/Cd(Ⅱ) Adsorption Removal and Bacterial Inactivation in Wastewater

An Ag-MnFe₂O₄-bentonite composite was synthesized by a chemical co-precipitation method and used for adsorption removal of Pb(Ⅱ), Cd(Ⅱ) and disinfection. The result of X-ray diffraction indicate that the diffraction peaks of MnFe₂O₄ and Ag can be perfectly indexed to the cubic spinel MnFe₂O₄(JCPDS No.88-1965) and metallic Ag(JCPDS No.41-1402), respectively. The results of scanning electron microscopy and energy dispersive X-ray spectroscopy manifest the deposition of MnFe₂O₄ and Ag on the bentonite surface and the presence of Mn, Fe and Ag. The result of X-ray photoelectron spectroscopy displayed that the composition of Ag-MnFe₂O₄-bentonite was Mn(Ⅱ), Fe(ⅡI) and metallic Ag. The analysis of Brunauer-Emmett-Teller showed that the specific surface area of Ag-MnFe₂O₄-bentonite was the largest compared with that of bentonite, MnFe₂O₄ and MnFe₂O₄-bentonite. Thermodynamic studies revealed that the adsorption of Pb(Ⅱ) and Cd(Ⅱ) ions was spontaneous and endothermic. Langmuir model showed an adsorption capacity of 129.87 mg/g for Pb(Ⅱ) and 48.31 mg/g for Cd(Ⅱ) ions. The adsorption kinetics of Pb(Ⅱ) and Cd(Ⅱ) ions onto Ag-MnFe₂O₄-bentonite can be best described by a pseudo-second-order model. The adsorption rate constant of the pseudo-second-order model was 0.0019 g·mg^-1·min^-1 for Pb(Ⅱ) and 0.0065 g·mg^-1·min^-1 for Cd(Ⅱ) ions. In addition to the adsorption experiment, the antibacterial properties of Ag-MnFe₂O₄-bentonite were studied through plate count method. Gram-negative(G-) bacteria Escherichia coli and Gram-positive(G+) bacteria Lactobacillus plantarum were used to test the antibacterial properties. The results showed that the composite demonstrated excellent antibacterial activity. Thus, Ag-MnFe₂O₄-bentonite can be employed as an adsorbent as well as an antimicrobial agent.     

一步共沉积法制备ZSM-5/PANI/PSS电活性膜及其电控选择性分离重金属Pb2+的动力学特性

本文采用双脉冲一步共沉积法制备了ZSM-5/聚苯胺/聚苯乙烯磺酸钠(ZSM-5/PANI/PSS)电活性膜,通过FT-IR、XRD和SEM对ZSM-5/PANI/PSS电活性膜进行了表征. 由水热法合成纳米级ZSM-5颗粒,经超声处理将ZSM-5分散,有利于合成均匀的ZSM-5/PANI/PSS电活性膜. 实验结果表明该电活性膜对Pb²⁺具有优良的选择分离性能,在10 mg﹒L^-1的Pb²⁺溶液中电控离子交换法对Pb²⁺的去除率是传统离子交换法的2.3倍,且前者的平衡吸附量是后者的2.5倍. 吸附过程满足Langmuir等温吸附方程,ZSM-5/PANI/PSS电活性膜对Pb²⁺的交换量高达235 mg·g^-1. 吸附过程为准一级动力学吸附,电控离子交换过程的准一级吸附速率常数(0.0227 g·mg^-1·min^-1)明显高于传统离子交换(0.0117 g·mg^-1·min^-1). 该电活性膜在电控离子交换处理废水领域具有很好的应用前景.     

芳氧基钇配合物引发丙烯腈溶液聚合的Monte Carlo模拟

用Monte Carlo方法模拟了DMF溶剂体系中单组分芳氧基钇引发剂Y(OAr)₃引发丙烯腈溶液聚合的全程反应动力学.通过计算机模拟和实验验证,表明聚合反应过程中存在配位阴离子活性中心,且活性中心容易形成,但很快失活.同时,存在向单体转移和向大分子转移两种链转移反应.获得了一组聚合反应动力学参数:k_i=0.053 L/(mol.m in),k_p=1.63 L/(mol.m in),k_d=0.005 8 m in^-1,k_tM=0.052 L/(mol.m in),k_trP=0.075 L/(mol.m in),k_pp=0 L/(mol.m in).     

娃儿藤碱类似物DCB-3501的全合成及其细胞毒性

以3,4-二甲氧基苯甲醛与3,4-二甲氧基苯乙酸为起始原料,经Perkin缩合、自由基氧化偶联反应、Swern氧化、还原胺化及付克酰基化等7步反应全合成了娃儿藤碱类似物DCB-3501,其结构经¹H NMR和ESI-MS确证。体外细胞毒性测试结果表明：DCB-3501对人结肠癌细胞HCT116、人胃癌细胞BGC-823、人肝癌细胞HepG-2、人宫颈癌细胞HeLa和人大细胞肺癌细胞H460的IC₅₀分别为20.0 μmol·L^-1, 50.9 μmol·L^-1, 2.1 μmol·L^-1, 65.8 μmol·L^-1和30.8 μmol·L^-1。     

氢气压力对煤加氢反应影响的热重-气相色谱实验研究

采用加压热重分析仪和气相色谱仪联用的方法研究了府谷烟煤和海拉尔褐煤加氢反应过程中的失重规律和主要气体产物析出规律,升温速率15℃/min,压力0.1~5.0MPa,反应终温1000℃。实验结果表明,煤粉加氢反应主要分为初始干燥脱气、热分解及挥发分加氢,半焦加氢气化和焦炭加氢气化四个阶段。氢气压力的提高促进了挥发分自由基的加氢反应,抑制了含氧官能团脱除形成碳氧化物。在热分解及挥发分加氢阶段,府谷烟煤失重速率随氢气压力的升高而减小,氢气压力对海拉尔褐煤失重速率的影响不大。在半焦加氢气化阶段,CH₄生成速率随氢气压力的升高而增大,当氢气压力较高时(3~5MPa),海拉尔褐煤CH₄生成速率随氢气压力的升高不再增大。海拉尔褐煤O_daf较高,其半焦中含氧官能团提供的活性位较多。府谷烟煤H/C原子比较高,能提供更多的内部氢。府谷烟煤和海拉尔褐煤焦炭加氢反应动力学参数分别为k₀=2.38×10⁷ (min^-1·MPa^-1),E=231kJ/mol,n=1和k₀=2.64×10³ (min^-1·MPa^-0.736),E=127kJ/mol,n=0.736。     

Synthesis and Visible-light Photocatalytic Performance of C-doped Nb2O5 with High Surface Area

C-doped Nb₂O₅ with abundant mesopores has been successfully synthesized through a facile solvothermal synthetic strategy followed by calcination treatment. The resulting C-doped Nb₂O₅ displayed the highest BET surface area(345 m²/g) and large mesopore size(ca. 4.2 nm), capable of offering more accessible active sites as well as faster mass transfer for catalysis. Besides, the doping of C(2.21%, molar fraction) at the O sites in Nb₂O₅ lattice greatly enhanced visible-light response by lowering the band gap, thereby making the material a photocatalyst under visible-light irradiation. Typically, the C-doped Nb₂O₅ exhibited a high H₂ evolution rate of ca. 39.10 μmol·g^-1·h^-1 and also degraded RhB dye completely after 30 min of visible light exposure, which turned out to be much better than Degussa P25 and pure Nb₂O₅ catalysts.     

Keggin 型磷钨酸盐修饰碳糊电极传感多巴胺的研究

多金属氧酸盐作为一类阴离子簇合物,由于其结构的多样性和尺寸大小的可调变性,在电化学、催化和药学等领域引起了人们的广泛关注.本文制备了多酸Co(C₁₅N₆H₁₂)₂[PW₁₂O₃₈]·5H₂O（Co[PW₁₂O₃₈]）修饰碳糊电极并通过电化学阻抗谱、循环伏安法以及差分脉冲伏安法对多巴胺的传感性能进行了研究.对其制备条件和检测条件分别进行了优化.在优化条件下,制备的传感器对多巴胺具有良好的选择性和灵敏度的检测能力.多巴胺的线性响应范围为8.0x10^-6 mol·L^-1至3x10^-5 mol·L^-1,灵敏度为0.039 μA·(μmol·L^-1)^-1,检出限（S/N=3）为5.4 x10^-6 mol·L^-1. 制备的多酸修饰碳糊电极用于检测多巴胺表现出良好的稳定性和重现性,并且对抗坏血酸、尿酸等常见的干扰物质,具有良好的抗干扰性. 多酸修饰的碳糊电极制备过程简单方便,成本低,传感性能良好,对应用于电化学传感器检测多巴胺具备潜在的应用前景.      

金属离子与卟啉的嵌入反应动力学研究(Ⅳ)──乳酸缓冲体系中四吡啶基卟啉衍生物与铜(Ⅱ)的配位反应

研究了在35±0.1℃、离子强度0.5mol/L(KCI)下,乳酸根催化Cu²⁺离子嵌入溴化间-四(N-乙酸甲酯基-3-吡啶基)卟啉和溴化间-四(N-氰乙基-3-吡啶基)卟啉的反应动力学。根据催化剂浓度、溶液的pH值与反应速率间的关系,得到Cu²⁺离子嵌入该类卟啉的反应动力学方程。实验结果表明,该类反应遵循负离子催化卟啉变形机理,变形的卟啉及其与乳酸根离子的缔合物为可能的活性中间体。     

新型含游离羟基鱼藤素衍生物的合成及其抗肿瘤活性

以鱼藤酮为原料经3步反应合成鱼藤素; 鱼藤素分别经三溴化硼脱甲基和硼氢化钠还原合成了4个新型含游离羟基的鱼藤素衍生物（3a~3c和4）,其结构经^1H NMR,¹³C NMR和LC-MS表征。初步的抗肿瘤活性测定结果表明,12-羟基鱼藤素（4）对人乳腺癌细胞MCF-7和人肺癌细胞H299的抑制活性较好,其IC₅₀分别为0.11 μmol·L^-1和0.01 μmol·L^-1,优于阳性对照药Deguelin。     

具有cGPX活力的含硒抗体酶的酶学及动力学性质研究

通过单克隆抗体制备技术得到三株特异结合半抗原4(GSH-S-DNP二苄酯)的单克隆抗体HB4,HB5和HB7.抗体经两步化学诱变得到具有细胞谷胱甘肽过氧化物酶(cGPX)活性的含硒抗体酶mHB4,mHB5和mHB7,活力分别为170,1867,32U/μmol.其中mHB5的活力是天然兔肝cGPX的0.32倍,m4A4的1.51倍.等离子体-质谱(ICP/MS)测得每分子含硒抗体酶分子中大约存在2个硒原子.mHB5的最适pH为8.6～8.8.在pH值范围为7.0和37℃条件下,mHB5催化GSH和H₂O₂或t-ROOH反应的二级速率常数为:_k+1(H₂O₂)9.71×10⁶L/(mol·min),_k+1(t-ROOH)5.99×10⁵L/(mol·min).mHB5使非酶催化反应速率提高了9.8×10⁶和3.7×10⁵倍.     

双显色剂高灵敏协同显色反应的研究——钼-溴邻苯三酚红-乙基紫体系

本文研究了在聚乙烯醇存在下,钼(Ⅵ)与溴邻苯三酚红和碱性染料-乙基紫产生的协同显色反应。探讨了利用协同显色反应进行分光光度测定痕量钼的可能性。在乙酸介质中,钼(Ⅵ)与溴邻苯三酚红和乙基紫形成[EV]₃[MoO₂(BPR)]离子缔合型配合物,其吸收峰位于535nm,相应试剂(BPR+EV)的吸收峰则位于640nm。摩尔吸光系数e₅₃₆=1.70×10⁵L·mol^-1·cm^-1。双峰双波长法可使灵敏度倍增。Δε_535～640=3.20×10⁵L·mol^-1。钼含量为0～0.16^μg/mL时,吸光度遵守比尔定律。桑德尔灵敏度(S)为0.00057μg/cm²。反应具有较高的选择性,除锗、钛、钨、钒有较严重干扰以外,其它常见金属离子不干扰钼的显色。根据配合物的组成,推测了它的可能结构。     

MOF derived Co3O4/N-doped carbon nanotubes hybrids as efficient catalysts for sensitive detection of H2O2 and glucose

Developing enzyme-free sensors with high sensitivity and selectivity for H2O2 and glucose is highly desirable for biological science.Especially,it is attractive to exploit noble-metal-free nanomaterials with large surface area and good conductivity as highly active and selective catalysts for molecular detection in enzyme-free sensors.Herein,we successfully fabricate hollow frameworks of Co3O4/N-doped carbon nanotubes(Co3O4/NCNTs)hybrids by the pyrolysis of metal-organic frameworks followed by calcination in the air.The as-prepared novel hollow Co3O4/NCNTs hybrids exhibit excellent electrochemical performance for H2O2 reduction in neutral solutions and glucose oxidation in alkaline solutions.As sensor electrode,the Co3O4/NCNTs show excellent non-enzymatic sensing ability towards H2O2 response with a sensitivity of 87.40μA(mmol/L)^-1 cm^-2,a linear range of 5.00μmol/L-11.00 mmol/L,and a detection limitation of 1μmol/L in H2O2 detection,and a good glucose detection performance with 5μmol/L.These excellent electrochemical performances endow the hollow Co3O4/NCNTs as promising alternative to enzymes in the biological applications.     

基于叶片状氧化铜纳米材料的无酶葡萄糖传感电极

将Nafion交联剂与纳米材料修饰至玻碳电极基底制备一种无酶葡萄糖传感器,通过循环伏安曲线、时间-电流曲线检测该电极电化学特性. 氧化铜纳米复合膜具有高比表面积和多活性点位的优点. 实验结果表明,氧化铜纳米电极对葡萄糖的检测线性响应范围0.01 ~ 0.3 mmol·L^-1,灵敏度1783.58 μA·L·mmol^-1·cm^-2,检测限0.80 μmol·L^-1 (S/N=3),稳定性较好,能抵抗抗坏血酸、多巴胺和尿酸干扰.     

铜修饰多孔镍自支撑电极的构建及其葡萄糖氧化性能

采用水热合成法制备了正八面体Cu₂O/Cu修饰的多孔Ni(NF)自支撑电极(Cu₂O/Cu-NF),并对其进行了形貌和结构表征。 在三电极体系下,在碱性介质中以循环伏安法和恒电位安培法测试其对葡萄糖催化氧化性能。 结果表明,150 ℃水热法制备的自支撑电极对葡萄糖的电催化氧化活性最强。 响应电流与葡萄糖浓度在3.7×10^-3~1.1 mmol/L和1.4~5.0 mmol/L范围内呈线性相关,响应灵敏度分别是6929和706.1 μA/(mmol·L^-1·cm²),且具有良好的选择性和稳定性,对无酶葡萄糖传感器的发展有重要意义。     

多孔石墨烯分离CH4/CO2的分子动力学模拟

采用分子动力学方法模拟CH₄/CO₂混合气体在多孔石墨烯分离膜中的分离过程, 分析了3 种纳米孔功能化修饰(N/H 修饰、全H修饰和N/―CH₃修饰)对分离过程的影响规律. 模拟结果表明气体分子会在石墨烯表面形成吸附层, CO₂分子的吸附强度高于CH₄分子. 纳米孔的功能化修饰不仅减小了纳米孔的可渗透面积, 还通过影响纳米孔边缘原子的电荷分布提高了气体分子的吸附强度, 进而影响了混合气体分子在多孔石墨烯分离膜中的渗透性和选择性. CO₂分子在多孔石墨烯中的渗透率能达到10⁶ GPU (1 GPU=3.35×10^-10 mol·s^-1·m^-2·Pa^-1), 远远高于传统的聚合物分离膜. 研究表明多孔石墨烯分离膜在天然气处理、CO₂捕获等工业气体分离过程中具有广泛的应用前景.     

基于WS2量子点材料固定葡萄糖氧化酶的直接电化学及其生物传感研究

采用水热法制备水溶性WS₂量子点（WS₂ QDs）材料,并将该材料进一步用于葡萄糖氧化酶（GOx）的有效固定,构建GOx/W₂ QDs/GCE传感界面. 采用透射电镜、紫外-可见光谱和电化学等方法对材料的形貌、GOx的固定化过程,以及传感器的直接电化学和电催化性能进行了表征. 结果表明,WS₂ QDs材料能够有效促进GOx与电极之间的直接电子转移. 并且,基于该传感器对葡萄糖良好的电催化作用,该方法有效实现了对葡萄糖的高灵敏检测,其线性范围为25 ~ 100 μmol·L^-1和100 ~ 600 μmol·L^-1,检测限为5.0 μmol·L^-1（S/N=3）. 该传感器具有良好的选择性、重现性和稳定性,可用于实际样品血糖的分析测定.     

A high-efficient amperometric hydrazine sensor based on novel electrospun CoFe2O4 spinel nanofibers

HeterojunctionFe_2O_3 nanoparticles(NPs), NiFe_2O_4 nanofibers(NFs), and CoFe_2O_4 NFs were synthesized by electrospinning and the subsequent thermal treatment processes. Characterization results indeed display the three-dimensional net-like textural structures of these as-electrospun spinel-type MFe_2O_4 NFs. The MFe_2O_4 NFs-based film configurations possess abundant micro/meso/macropores on their surface. These structures could afford more accessible transport channels for effective reduction of the mass transport resistance and improvement of the density of exposed catalytic active sites. All these advantages are responsible for the enhanced electro-catalytic performance of these MFe_2O_4 NFs in hydrazine oxidation. When used for hydrazine detection, CoFe_2O_4 NFs show the best catalytic efficiency.For example, the CoFe_2O_4 NFs possess a large sensitivity of 1327 mA cmà2(mmol Là1[à1in the linear range of 0.01 to 0.1 mmol Là1and 503 mA cmà2(mmol Là1)à1in the linear range of 0.1 to 11 mmol Là1, a response time of shorter than 3 s, good reproducibility and remarkable long-term stability. The superior catalytic efficiency, excellent stability, low cost, and ease of fabrication render CoFe_2O_4 NFs very promising materials in developing an electrochemical device that directly detects hydrazine.     

新型GPR40激动剂的合成及其生物活性

以丁炔二醇为起始原料,用叔丁基二甲基氯硅烷进行单保护后,与2-(6-羟基-2,3-二氢苯并呋喃)乙酸甲酯经Mitsunobu反应制得2-{6-［4-(叔丁基二甲硅烷氧基)丁-2炔基氧基］-2,3-二氢苯并呋喃}乙酸甲酯(3); 3脱除保护后与苯酚衍生物发生Mitsunobu反应,随后经水解合成了6个结构新颖的苯并二氢呋喃衍生物(7a~7f),其结构经¹H NMR, ¹³C NMR和HR-EI-MS表征。GPR40激动活性测试结果表明：7a~7f对GPR40均有激动作用,其中7e和7f激动活性最强,EC₅₀分别为0.593 μmol·L^-1和0.596 μmol·L^-1。     

硝酸对N,N-二甲基羟胺γ-辐解及液态辐解产物的影响

N,N-二甲基羟胺(DMHA)是用于动力堆乏燃料后处理U与Pu和Np分离的新型无盐还原剂, 本文研究了硝酸对DMHA γ-辐解及液态辐解产物的影响. 研究结果表明: 在U、Pu分离循环和Pu纯化循环的辐照剂量下, 在0.3-1.0 mol·L^-1的硝酸溶液中, 0.1 和0.5 mol·L^-1 DMHA具有较好的辐照稳定性. 当吸收剂量为5-25kGy时, DMHA硝酸溶液的液态辐解产物主要有单甲基羟胺、甲醛、甲酸和亚硝酸. 有机物的浓度远远高于亚硝酸浓度, 且随着剂量和硝酸浓度的增加而增大. 对于相同的硝酸浓度和剂量, 0.1 mol·L^-1 DMHA辐解产生的一甲基羟胺的浓度高于0.5 mol·L^-1 DMHA, 但前者辐解产生的甲醛浓度低于后者; 当硝酸浓度较高时, 0.1 mol·L^-1 DMHA辐解产生的甲酸浓度高于0.5 mol·L^-1 DMHA. 亚硝酸浓度与硝酸浓度及剂量的关系取决于起始DMHA和硝酸浓度.