GREEN CHEMISTRY
·
2012
·Vol. 14
·期 6
·1705-1709
·
IF 6.32
Weiming Wu,Guodong Liu,Quanhua Xie,Shijing Liang,Huarong Zheng,Rusheng Yuan,Wenyue Su,Ling Wu
Highly efficient photocatalytic reduction of 4-nitroaniline to p-phenylenediamine over a commercial CdS photocatalyst was observed under visible light irradiation (λ ≥ 420 nm) in water. The conversion of 4-nitroaniline and the selectivity of p-phenylenediamine were ∼100% and ∼98% after 9 min of visible light irradiation, respectively. The photoreduction efficiency of 4-nitroaniline over the CdS photocatalyst remained above 95% in the 5th cycle of testing. Its photocatalytic activity was much higher than those of nitrogen-doped TiO2 and commercial TiO2 photocatalysts. Further experimental results revealed that the ammonium formate and N2 atmosphere were indispensable for the photocatalytic reduction of 4-nitroaniline over the CdS photocatalyst. On the basis of the results of electron spin resonance, photoexcited electrons and ·CO2− radicals were detected in the present system. These species had strong reductive powers, and were therefore able to efficiently reduce 4-nitroaniline to p-phenylenediamine.
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BIOCHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 2.467
Qin Xu,Wei-Yi Tao,He Huang,Shuang Li
An NADPH-dependent carbonyl reductase (YlCR2) from Yarrowia lipolytica was discovered by genome mining, overexpressed in Escherichia coli BL21 and purified to homogeneity. To efficiently synthesize ethyl ( S )-4-chloro-3-hydroxybutanoate (( S )-CHBE) (99%, e.e), the highly stereoselective bioreduction of ethyl 4-chloro-3-oxobutanoate (COBE) into ( S )-CHBE with the recombinant E. coli BL21/pETYlCR2 was successfully demonstrated in an n -butyl acetate-water biphasic system (1:1, v/v) with NADPH self-regeneration by substrate-coupled system using sorbitol or mannitol as co-substrate. The optimum reaction condition for the biotransformation of COBE in the biphasic system were 3000 mM COBE, (1.2 or 1.3 mmol/mmol COBE) mannitol or sorbitol, 0.2 mM or 0.4 mM NADP + , 0.12 or 0.14 g (wet weight)/ml cell dosage, pH 5.0, 30 °C; ( S )-CHBE with yield of 90% and e.e of 99% was obtained after 10 h reaction. Furthermore, 3000 mM COBE could also be completely biotransformed after 20 h without addition of expensive cofactor NADP + . Significantly, E. coli BL21/pETYlCR2 shows the high potential in the industrial production of ( S )-CHBE.
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DALTON TRANSACTIONS
·
2015
·Vol. 44
·期 47
·20562-20567
·
IF 4.197
Su-Yun Zhang,Wen-Bin Guo,Ming Yang,Ying-Ying Tang,Mei-Yan Cui,Nan-Nan Wang,Zhang-Zhen He
Cu5(VO4)2(OH)4 (turanite) is a layered compound, exhibiting a copper(II) oxide layer in the [0 1 1] plane composed of edge-sharing CuO6 octahedra. Each Cu–O layer is further separated by VO4 tetrahedra. Closer scrutiny found that the copper(II) oxide layer in the compound represents a totally new geometrically-frustrated lattice, a 1/6 depleted triangular lattice. More specifically, the spin network in the [0 1 1] plane is formed by the alternate ranking of triangular and honeycomb strips. Magnetic measurements show that the Cu5(VO4)2(OH)4 behaves as a spin-1/2 ferrimagnet with a Tc = ∼4.5 K. It exhibits an unusual 1/5 magnetization plateau arising from the competition between antiferromagnetic and ferromagnetic interactions caused by the strong frustration. The possible spin-arrangements are also suggested.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Qi Zhao,Zhencheng Chen,Chen-Wei Shan,Tao Zhan,Chen-Yang Han,Guo-Cheng Han,Xiao-Zhen Feng,Heinz-Bernhard Kraatz
Human chorionic gonadotropin (HCG), a vital protein for pregnancy determination and a marker for trophoblastic diseases , finds application in monitoring early pregnancy and ectopic pregnancy . This study presents an innovative approach employing electrochemical immunosensors for enhanced HCG detection, utilizing Anti-HCG antibodies and gold nanoparticles (AuNPs) in the sensor platform. Two sensor configurations were optimized: BSA/Anti-HCG/c-AuNPs/MEL/e-AuNPs/SPCE with [Fe(CN) 6 ] 3−/4− as a redox probe (1) and BSA/Anti-HCG/PPy/e-AuNPs/SPCE using polypyrrole (PPy) as a redox probe (2). The first sensor offers linear correlation in the 0.10–500.00 pg∙mL −1 HCG range, with a limit of detection (LOD) of 0.06 pg∙mL −1 , sensitivity of 32.25 μA∙pg −1 ∙mL∙cm −2 , RSD <2.47 %, and a recovery rate of 101.03–104.81 %. The second sensor widens the HCG detection range (40.00 fg∙mL −1 -5.00 pg∙mL −1 ) with a LOD of 16.53 fg∙mL −1 , ensuring precision (RSD <1.04 %) and a recovery range of 94.61–106.07 % in serum samples. These electrochemical immunosensors have transformative potential in biomarker detection, offering enhanced sensitivity, selectivity , and stability for advanced healthcare diagnostics.
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ChemElectroChem
·
2016
·Vol. 3
·期 11
·1781-1786
·
IF 3.506
Xiao Huang,Yaofang Xuan,Lisiqi Xie,Bin Su
Graphical Phase-transfer catalysis : Fe III meso -tetra-(4- N -methyl-pyridyl) porphine (Fe III TMPyP) is found to catalyze oxygen reduction at the liquid/liquid interface. Based on the size-selective ion-transfer voltammetry at the nanoscopic liquid/liquid interface, the reaction is rationalized to proceed through the phase-transfer catalysis mechanism. We report an investigation of the oxygen reduction reaction (ORR) catalyzed by Fe III meso -tetra-(4- N -methyl-pyridyl) porphine (Fe III TMPyP) at the polarized water/1,2-dichloroethane (DCE) interface. Fe III TMPyP is a water soluble pentavalent cation, which has a standard Galvani transfer potential of +0.19 V at the water/DCE interface. By four-electrode cyclic voltammetry and shake-flask biphasic reactions controlled by chemical polarization at the macroscale water/DCE interface, we demonstrated that Fe III TMPyP can catalyze the reduction of O 2 by electron donors (e.g., ferrocene and 1,1′-dimethylferrocene). Further, based on voltammetry at the free-standing silica nanochannel membrane (SNM) supported nano-ITIES (interface between two immiscible electrolyte solutions) array where the transfer of Fe III TMPyP is physically blocked owing to the size-exclusion effect, we proved that the overall reaction proceeds through a phase-transfer catalysis (PTC) process, namely the heterogeneous ion transfer of Fe III TMPyP from water to DCE followed by the homogeneous catalyzed ORR in DCE.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2017
·
IF 3.154
Yehong Han,Chunliu Yang,Yang Zhou,Dandan Han,Hongyuan Yan
A new method involving ionic liquid–hybrid molecularly imprinted material–filter solid-phase extraction coupled to high-performance liquid chromatography (IL–HIM–FSPE–HPLC) was developed for the simultaneous isolation and determination of 6-benzyladenine (6-BA) and 4-chlorophenoxyacetic acid (4-CPA) in bean sprouts. Sample preconcentration was performed using a modified filter, with the new IL–HIM as the adsorbent, which shows double adsorption. The first adsorption involves special recognition of molecular imprinting, and the second involves ion exchange and electrostatic attraction caused by the ionic liquid. This method combines the advantages of ionic liquids, hybrid materials, and molecularly imprinted polymers and was successfully applied to determine 6-BA and 4-CPA in bean sprouts. The adsorption of 6-BA to IL–HIM is based on selective imprinted recognition, whereas the adsorption of 4-CPA is mainly dependent on ion-exchange interactions.
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Analytical Methods
·
2015
·Vol. 7
·期 10
·4246-4251
·
IF 1.821
Pinong Huang,Suqing Zhao,Sergei A. Eremin,Shengwu Zheng,Dan Lai,Yingshan Chen,Bin Guo
Based on a sensitive monoclonal antibody against bisphenol A (BPA) and a new tracer named BVA–AMF, a homogeneous fluorescence polarization immunoassay (FPIA) was developed and applied in the determination of bisphenol A in environmental water samples. BVA was selected as the hapten to couple with bovine serum albumin and the conjugate was used as the immunogen for the monoclonal antibody production. Three fluorescein-labeled BVA tracers with different structures (BVA–AMF, BVA–EDF, and BVA–lysFITC) were synthesized. Under the same optimal conditions, BVA–AMF showed the highest sensitivity for FPIA and the detection of BPA exhibited a limit of detection of 5.60 ng mL−1, an IC50 of 140 ng mL−1 and a dynamic range of 11.32–904.21 ng mL−1 approximately. In this assay, several similar compounds were shown of little significantly with the cross-reactivity being less than 0.15%. Four different kinds of water samples were analyzed, with recoveries being 87.91–114.28%. The detection standard curve of BPA exhibited a good linearity (R2 = 0.9913, n = 3). Compared with ELISA and HPLC methods, FPIA showed reliability and a high correlation with ELISA of 0.9964 and HPLC of 0.9971. The proposed immunoassay technique is suitable for detection of BPA in authentic environmental water samples.
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ANALYTICA CHIMICA ACTA
·
2014
·
IF 4.517
Kao Zhu,Xianyun Hu,Qinyu Ge,Qingjiang Sun
We have developed a new fluorescent probe of thioglycolic acid (TGA)-capped CdTe quantum dots (QDs) complexed with a model drug, meso -tetrakis( N -methylpyridinium-4-yl)porphyrin (TMPyP) for detecting deoxyribonucleic acids (DNAs). This probe operates with an “Off–On” mode: TMPyP quenches the photoluminescence (PL) of QDs via a photo induced electron-transfer (PIET) process; the presence of DNA can break the QD/TMPyP complexation, interrupting the PIET process, and switch on the PL of QDs. Sensitive detection of DNA with the detection limit of 0.16 nM and a linear detection range of 0.25–6.0 nM are achieved. Importantly, this probe can be used to distinguish the binding modes of DNA–TMPyP interactions, exhibiting the DNA sequence-dependent PL recovery behaviors. The obtained binding constant for poly(dA)·poly(dT) is ∼3.30 × 10 7 L mol −1 , which is approximately one order of magnitude larger than those for native DNAs and poly(dG)·poly(dC). Furthermore, the thymine bases preferential of the TMPyP–DNA interaction is proved by this probe.
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Journal of Inorganic and Organometallic Polymers and Materials
·
2013
·Vol. 24
·期 3
·582-590
·
IF 1.174
Li Xin,Bi Cai-Feng,Fan Yu-Hua,Zhang Xia,Zhang Nan,Yan Xing-Chen
A novel transition metal coordination polymer [Co 3 (C 14 H 8 NO 4 Cl) 4 (CH 3 OH) 4 ·4CH 3 OH] n with Schiff base (C 14 H 8 NO 4 Cl: 4-chloroanthranilic acid- 2,4-dihydroxybenzaldehyde) was synthesized using 4-chloroanthranilic acid, 2,4-dihydroxybenzaldehyde and cobalt(II) acetate as source, and its structure was characterized by IR spectroscopy, elemental analysis, 1 H NMR and single crystal X-ray diffraction. X-ray crystallography shows that every cobalt atom is six-coordinated. Two cobalt atoms on the two sides are respective coordinated with two nitrogen atoms from –C=N–, two carboxylic oxygen atoms and two hydroxyl oxygen atoms in different ligands, while the cobalt atom in the middle links two ligands on the side through two carboxylic oxygen atoms and coordinates with four oxygen atoms of methanol, forming a three-nuclear Co(II) complex. The complex forms a two-dimensional layer structure through O–H···O intermolecular hydrogen bonds. The interaction of the Co(II) complex with calf-thymus DNA (CT-DNA) was investigated by UV absorption spectroscopy, fluorescence emission spectroscopy, viscosity and cyclic voltammetry. All measurements revealed that the Co(II) complex binds to DNA via a intercalative mode.
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CHEMISTRY OF MATERIALS
·
2014
·
IF 8.535
Qingwen Tian,Gang Wang,Wangen Zhao,Yanyan Chen,Yanchun Yang,Lijian Huang,Daocheng Pan
We developed a versatile and environmentally friendly solution approach for the fabrication of a variety of metal sulfide nanocrystal thin films. Metal oxides, metal hydroxides, metal chlorides, metal acetates, and metal acetylacetonates can be used as the starting materials and dissolved in thioglycolic acid and ethanolamine, forming many types of metal–organic precursor solutions. High quality CdS, SnS, CuInS2, CuSbS2, Cu2ZnSnS4, Cu(In0.7Ga0.3)S2, and luminescent Ag-doped ZnxCd1–xS nanocrystal thin films have been successfully prepared by spin-coating their corresponding metal precursor solutions. Cu2ZnSn(S,Se)4 thin film solar cell with a power conversion efficiency of 6.83% has been realized by this versatile method.
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Microbial Cell Factories
·
2017
·Vol. 16
·期 1
·1-10
·
IF 3.681
Xiong Liang-Bin,Liu Hao-Hao,Xu Li-Qin,Sun Wan-Ju,Wang Feng-Qing,Wei Dong-Zhi
Background The strategy of modifying the sterol catabolism pathway in mycobacteria has been adopted to produce steroidal pharmaceutical intermediates, such as 22-hydroxy-23,24-bisnorchol-4-ene-3-one (4-HBC), which is used to synthesize various steroids in the industry. However, the productivity is not desirable due to some inherent problems, including the unsatisfactory uptake rate and the low metabolic efficiency of sterols. The compact cell envelope of mycobacteria is a main barrier for the uptake of sterols. In this study, a combined strategy of improving the cell envelope permeability as well as the intracellular sterol metabolism efficiency was investigated to increase the productivity of 4-HBC.Results
MmpL3, encoding a transmembrane transporter of trehalose monomycolate, is an important gene influencing the assembly of mycobacterial cell envelope. The disruption of mmpL3 in Mycobacterium neoaurum ATCC 25795 significantly enhanced the cell permeability by 23.4% and the consumption capacity of sterols by 15.6%. Therefore, the inactivation of mmpL3 was performed in a 4-HBC-producing strain derived from the wild type M. neoaurum and the 4-HBC production in the engineered strain was increased by 24.7%. Subsequently, to enhance the metabolic efficiency of sterols, four key genes, choM1, choM2, cyp125, and fadA5, involved in the sterol conversion pathway were individually overexpressed in the engineered mmpL3-deficient strain. The production of 4-HBC displayed the increases of 18.5, 8.9, 14.5, and 12.1%, respectively. Then, the more efficient genes (choM1, cyp125, and fadA5) were co-overexpressed in the engineered mmpL3-deficient strain, and the productivity of 4-HBC was ultimately increased by 20.3% (0.0633 g/L/h, 7.59 g/L 4-HBC from 20 g/L phytosterol) compared with its original productivity (0.0526 g/L/h, 6.31 g/L 4-HBC from 20 g/L phytosterol) in an industrial resting cell bio-transformation system.Conclusion sIncreasing cell permeability combined with the co-overexpression of the key genes (cyp125, choM1, and fadA5) involved in the conversion pathway of sterol to 4-HBC was effective to enhance the productivity of 4-HBC. The strategy might also be useful for the conversion of sterol to other steroidal intermediates by mycobacteria.
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RSC Advances
·
2017
·Vol. 7
·期 3
·1432-1438
·
IF 3.108
Jinshui Liu,Meijiao Xu,Bin Wang,Zihan Zhou,Lizhen Wang
An easy-to-use fluorescent probe for detecting protamines was developed. Protamines are detected using the probe because of competitive interactions of polyacrylic acid modified with sodium 4-amino-1-naphthalenesulfonate (ANS-PAA) with protamines and aminated graphene oxide (GO-NH2). The ANS-PAA fluorescence was effectively quenched by the GO-NH2, the high quenching efficiency being caused by the ANS-PAA becoming non-covalently bound to the GO-NH2 surface through electrostatic interactions, forming a ANS-PAA/GO-NH2 complex. Adding protamines recovered the fluorescence of the ANS-PAA/GO-NH2 complex. This recovery was due to the positively charged protamines removing ANS-PAA from the GO-NH2 surfaces and forming ANS-PAA/protamine complexes. Displacement of GO-NH2 by protamines gave a high fluorescence recovery efficiency. Under optimal conditions, the fluorescence intensity when protamines were added was proportional to the protamine concentration over the range 0 to 6.0 μg mL−1. The detection limit was 0.4 μg mL−1. This approach offers a new quantitative method for determining protamines.
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