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    25 September 2012, Volume 28 Issue 5
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    Cover and Content of Chemical Research in Chinese Universities Vol.28 No.5(2012)
    2012, 28(5):  0-0. 
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    Articles
    Preparation, Characterization and Properties of Graphene-silver Sulphide Hybrid
    CHEN Guang-yi, WEI Zhi-yong, LIANG Ce, WANG De-jin, LIANG Ji-cai, ZHANG Wan-xi
    2012, 28(5):  757-759 . 
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    A facile and efficient strategy was reported for the preparation of graphene nanosheets-Ag2S hybrid by a simple hydrothermal process. First, Ag2S particles deposited on the surface of graphene oxide(GO) sheet. GO was then reduced by hydrazine hydrate to graphene. The results of X-ray diffraction(XRD) and Fourier transform infrared(FTIR) demonstrated the efficient reduction of GO to graphene. Transmission electron microscopy(TEM) image of the sample reveals the morphology of the architecture of graphene-Ag2S hybrid. Ultraviolet-visible spectroscopy(UV-Vis) and photoluminescence(PL) measurement were further employed to study the optical properties of the obtained nanocomposite. This work can be extended to design other graphene-based hybrid nanomaterials, and the as-grown architectures may hold promise for many applications.
    Hydrothermal Synthesis and Characterization of Perovskite Oxide AgTaO3
    HE Li-jie, ZHANG Dong, FENG Shou-hua, ZOU Bo, CHEN Gang
    2012, 28(5):  760-763 . 
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    The perovskite-type AgTaO3 crystals were prepared by mild hydrothermal method and determined by powder X-ray diffraction. Rietveld refinement indicates that AgTaO3 crystallized in an orthorhombic system with the space group Pcmn. The lattice parameters are a=5.5822(1) nm, b=7.8522(2) nm and c=5.5347(1) nm, with α=β=γ= 90.0o. The compound was characterized by scanning electron microscopy(SEM), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy(HR-TEM) and UV-Vis diffuse reflectance spectrometry (UV-Vis DRS). The photocatalytic activity of AgTaO3 powder was evaluated by the degradation of Congo red under UV-light irradiation. The result shows that the titled compound has a high photocatalytic activity at room temperature and potential application in photocatalysis.
    Hydrothermal Synthesis and Luminescent Properties of Flowerlike Zn2GeO4 and Mn2+-Doped Zn2GeO4 Hierarchical Architectures
    LI Bo, SONG Shu-yan, SUN Xiu-juan, PENG Jing, WANG Bo, XING Yan
    2012, 28(5):  764-767 . 
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    Three-dimensional(3D) flowerlike hierarchical Zn2GeO4 and Mn2+-doped Zn2GeO4 microstructures have been prepared by a facile hydrothermal approach. X-Ray diffraction(XRD), field emission scanning electron microscopy(FESEM), transmission electron microscopy(TEM) and photoluminescence(PL) spectrometry were employed to characterize the samples. Such flowerlike hierarchical Zn2GeO4 microstructures with an average diameter of 3―4 μm were found to be constructed by abundant single crystalline nanorods of about 90 nm in diameter. The luminescent properties of Zn2GeO4:xMn phosphors with different contents of Mn2+ as an activator were investigated. The Mn2+-doped samples showed green luminescence corresponding to the d-d transition of Mn2+ under the irradiation of UV light. The red shift(from 531 nm to 538 nm) in λem with increasing Mn2+ content was observed in the luminescent spectra, which should be attributed to a weak crystal field because of the substitution of Zn2+ by Mn2+ at a distorted tetrahedral lattice site.
    Vanadium Haloperoxidases Model Compounds: Synthesis, Structural Characterization and Mimic Catalytic Bromination Activity of [VO(C2O4)(2,2′-bipy)(H2O)]·C2H5OH and VO(C2O4)(phen)(H2O)
    REN Dong-xue, CAO Yun-zhu, CHEN Chen, XING Yong-heng
    2012, 28(5):  768-774 . 
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    Two oxo-vanadium(IV) complexes, [VO(C2O4)(2,2′-bipy)(H2O)]·C2H5OH(1) and VO(C2O4)(phen)(H2O) (2), where 2,2′-bipy=2,2′-bipyridyl, phen=1,10-phenanthroline, were synthesized as potential functional models of vanadium haloperoxidases(VHPOs) in mixed solvent of ethanol and water at room temperature. The complexes were characterized by elemental analysis, infrared(IR), UV-Vis and X-ray crystallography. Structural analyses showed that vanadium atom was coordinated by a terminal oxygen, one oxygen atom from coordinated water, two oxygen atoms from the carboxylate group of oxalic acid, and two nitrogen atoms(N1 and N2) from 2,2′-bipy/phen. Central vanadium atoms in complexes 1 and 2 were both in a distorted-octahedral environment, and some intermolecular hydrogen bonding linkages were also observed in each complex. Bromination reaction activity of the two complexes was evaluated with phenol red as organic substrate in the presence of H2O2, Br- and phosphate buffer, indicating that they can be considered as a potential functional model of VHPO. In addition, thermal analysis was also performed and discussed in detail.
    Syntheses and Structures of Two Coordination Polymers Containing Macrocyclic Oxamide and Isophthalic Acid Derivatives
    WU Lin, SUN Ya-qiu, LIU Xiao-xu, GAO Dong-zhao, XU Yan-yan, ZHANG Guo-ying
    2012, 28(5):  775-779 . 
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    Two novel coordination polymers [Cd(NiL)(aipt)](1) and [Mn(nipt)(NiL)2]稨2O(2)(NiL, H2L=2,3-dioxo- 5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien, H2aipt=5-aminoisophthalic acid, H2nipt=5-nitroisoph- thalic acid) were hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Compounds 1 and 2 consist of different 1D chains including both oxamide and 5-aminoisophthalate or 5-nitroisophthalic bridge. And all these chains were further interlinked via hydrogen bonds, resulting in a 2D architecture in compounds 1 and 2.
    Preparation and Supercapacitive Properties of Fe2O3/Active Carbon Nanocomposites
    LUO Pei-wen, YU Jian-guo, SHI Zhi-qiang, HUANG Hua, LIU Lang, ZHAO Yong-nan, LI Guo-dong, ZOU Yong-cun
    2012, 28(5):  780-783 . 
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    Fe2O3/active carbon(Fe2O3/AC) nanocomposites were readily fabricated by pyrolyzing Fe3+ impregnated active carbon in a nitrogen atmosphere. The as-prepared composites were studied by X-ray powder diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM). The capacitive property of the composites was investigated by cyclic voltammetry(CV) and galvanostatic charge-discharge test. Physical characterizations show that the γ-Fe2O3 fine grains dispersed in the AC well, with a mean size of 21.24 nm. Electrochemical tests in 6 mol/L KOH solutions indicate that the as-prepared nanocomposites exhibited improved capacitive properties. The specific capacitance(SC) of Fe2O3/AC nanocomposites was up to 188.4 F/g that was derived from both electrochemical double-layer capacitance and pseudo-capacitance, which was 78% larger than that of pristine AC. A symmetric capacitor with Fe2O3/AC nanocomposites as electrode showed an excellent cycling stability. The SC was only reduced by a factor of 9.2% after 2000 cycles at a current density of 1 A/g.
    Room Temperature Modulated Structure of Ca and K co-Doped LaMnO3
    HOU Chang-min, HUANG Ke-ke, HU Bin, YUAN Hong-ming, FENG Shou-hua
    2012, 28(5):  784-787 . 
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    A series of perovskite compounds of La1-x-yCaxKyMnO3 was prepared by hydrothermal disproportionation reaction of MnO2. The three oxidation states of manganese(Mn3+, Mn4+ and Mn5+) can stably exist in the compounds. Under room temperature conditions, twice and three times modulated structure produced by the charge ordering can be observed by X-ray diffraction(XRD), select area electron diffraction(SAED) and high resolution transmission electron microscopy(HR-TEM). The splits of the diffraction peaks of the single crystals confirmed by synchrotron X-ray diffraction experiment are in accordance with those of the powder sample. The existence of the different oxidation states of Mn3+, Mn4+ and Mn5+ can be considered to be the dominating reason of the complicated room temperature modulated structure.
    Hydrothermal Synthesis and Dielectric Characterization of a Double Perovskite Ba2FeSbO6
    LI Min, YUAN Hong-ming, XU Wei, HAN Mei, YAO Lin-ran, YANG Ming, FENG Shou-hua
    2012, 28(5):  788-791 . 
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    A double perovskite oxide Ba2FeSbO6 was hydrothermally synthesized and structurally characterized by X-ray diffraction. This solid compound shows a single phase and has a trigonal structure with space group R m and cell parameters of a=0.57261 nm and c=1.40244 nm. The dielectric constant and loss tangent of the solid measured in a frequency range from 100 Hz to 1 MHz at temperatures from 313 K to 513 K reveal a relaxation process of frequency dependence of the real part(ε') of dielectric constant and dielectric loss tand. The frequency dependence of electrical property led to the framework of conductivity and electric modulus formalisms. The scaling behavior of imaginary part of electric modulus suggests that the relaxation describes the single mechanism at various temperatures. The variation tendency of the alternating current impedance indicates the thermally activated conduction process follows Jonsche’s power law.
    Detection of Penicillin via Surface Plasmon Resonance Biosensor
    ZHANG Ying, JIN Wei, YANG Meng-chao, ZHANG Ti-qiang, ZHOU Chao, XIE Fei, SONG Qi, REN Hao, JIN Qin-han, MU Ying
    2012, 28(5):  792-796 . 
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    A method of using Au colloid to capture the decomposed product of penicillin, penicillamine, on a surface plasmon resonance(SPR) biosensor for the quantitative determination of penicillin was developed. Based on the decomposition of penicillin to generate penicillamine and penilloaldehyde, a high sensitive biosensor for detecting penicillin was also developed. In our experiment, it was penicillamine rather than penicillin that has been measured. This is because penicillamine contains a functional group that makes it self-assembling on Au colloid to increase the molecular weight so as to improve the surface plasmon resonance signal. On a UV-Vis spectrophotometer, a high concentration of penicilliamine-Au complex was determined, indicating that penicillamine was already well combined with Au colloid. The method, using the combination of Au colloid with penicillamine, proved to detect penicillin.
    Stable Isotope Dilution Analysis of Gibberellin Residues in Tomato Paste by Liquid Chromatography-Tandem Mass Spectrometry
    SUN Li, ZHAO Yan-sheng, NIE Xue-mei, LING Yun, CHU Xiao-gang, SHANG De-jun, DONG Ying
    2012, 28(5):  797-801 . 
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    An accurate and sensitive method for the simultaneous determination of gibberellic acid(GA3), gibberellin A4(GA4) and gibberellin A7(GA7) residues in tomato paste was developed by coupling solid phase extraction to high performance liquid chromatography-tandem mass spectrometry(LC-MS/MS) with electrospray ionization based stable isotope dilution analysis(SIDA). The isotope labeled internal standard can compensate for the losses during the extraction and cleanup steps and for discrimination due to ion suppression. After extraction from methanol, hydrophile lipophilic balance(HLB) solid phase extraction(SPE) column was tested for the capacity of the cleanup of the tomato paste in compared with C18 SPE column which is the common way to the detection of GAs, and the former gained better result. Spiked experiments were performed in the non-contaminated tomato pastes and the recoveries of GA3, GA4 and GA7 were 42.6%―75.0% in external standard method(ESM) and 91.1%―103.8% in internal standard method(ISM) respectively. The validities of this method were investigated and good analytical performance for the three GAs was obtained, including low limits of method detection(2 ng/g for GA3 and GA4, 0.3 ng/g for GA7), excellent linear dynamic ranges(5―500 ng/g for GA3 and GA4, 1―100 ng/g for GA7) and good relative standard deviation ranges(4.8%―9.4% for the intra-day test and 3.5%―11.9% for the inter-day test).
    Simultaneous Forecast for Three Speciations of Heavy Metal Elements Using Fuzzy Cluster-Artificial Neural Network
    ZHAO Tian-qi, MENG Fan-yu, WANG Hong-yan, GAO Yan
    2012, 28(5):  802-806 . 
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    The three speciations(water extract, adsorption and organic speciations) of Cu, Zn, Fe and Mn in geo-chemical samples were determined by fuzzy cluster-artificial neural network(FC-ANN) method coupled with atomic absorption spectrometry. A back-propagation artificial neural network with one input node and three export nodes was constructed, which could forecaste three speciations of heavy metals simultaneously. In the learning sample set, the three speciations of each element were allowed to change in a wide concentration range and the accuracy of the analysis was apparently increased via the learning sample set optimized with the help of the fuzzy cluster analysis. The average relative errors of the three speciations of Cu, Zn, Fe or Mn from 100 geo-chemical samples were less than 5%. The relative standard deviations of the three speciations of each of four heavy metals were 0.008%―4.43%.
    Determination of Vanadyl Porphyrins by Liquid-liquid Microextraction and Nano-baskets of p-tert-Calix[4]arene Bearing Di-[N-(X)sulfonye Carboxamide] and Di-(1-propoxy) in Ortho-cone Conformation
    MOKHTARI Bahram, POURABDOLLAH Kobra
    2012, 28(5):  807-813 . 
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    Dispersive liquid-liquid microextraction technique was introducd to remove the centrifuging step and conduct inclusion microextraction of charged porphyrins by nano-baskets. For nano-baskets of p-tert-calix[4]arene bearing di-[N-(X)sulfonyl carboxamide] and di-(1-propoxy) in ortho-cone conformation was synthesized and used. The related parameters including ligand concentration, the volume of water disperser, salt effect, and extraction time were optimized. The linear range, detection limit(S/N=3) and precision(RSD, n=6) were determined to be 0.2―50, 0.07 μg/L and 5.3%, respectively. The results reveal that the new approach is competitive analytical tool and an alternative of the traditional methods in the crude oil and related systems.
    Determination of Xenon in Air by a Pulse-discharge Helium Ionization Detector
    CHEN Zhan-ying, CHANG Yin-zhong, LIU Shu-jiang, ZHANG Hai-tao, WANG Shi-lian, LI Qi
    2012, 28(5):  814-817 . 
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    A pulse-discharge helium ionization detector(Valco, PD-D3-I) was used to measure xenon concentration in air. The dependences of the detector relative response on various gas chromatograph parameters were investigated. Based on the well prepared gas connections for the detector system and optimized gas chromatography(GC) working conditions, the atmospheric xenon concentration could be measured by the cheap GC method with a detection level of 0.7?0-9(parts by volume). Moreover, the xenon concentration in the ground level air around our laboratory was measured with the result of 0.085?0-6(parts by volume) and RSD of 0.91%.
    Biostimulation-enhanced Biodegradation of Nitrobenzene in Contaminated Groundwater
    AN Yong-lei, ZHANG Lan-ying, LIU Na, ZHANG Lei, GAO Huan-fang
    2012, 28(5):  818-823 . 
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    In this study, biostimulation technology was used for bioremediation of nitrobenzene-contaminated groundwater by adding a mixture of lactose and phosphate, peptone, and beef extract. During the process of biostimulation, the remediation effectiveness, microbial dehydrogenase activities and microbial densities were investigated; the varieties of microbial community structure and composition were analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE) technique and the relative abundances of nitrobenzene-degrading gene(nbzA) were determined by fluorescence quantitative real-time PCR(RT-PCR). Findings show that the removal rate of nitrobenzene in groundwater could reach about 60% by biostimulation with lactose and phosphate, 70% with peptone and 68% with beef extract. The microbial dehydrogenase activities and microbial densities were all improved obviously via biostimulation. The results of PCR-DGGE show that the microbial diversities were improved, and more than ten kinds of dominant microorganisms were detected after biostimulation. RT-PCR results show that the relative abundances of nbzA gene of microbes in groundwater were increased significantly, which indicated that biostimulation actually enhanced the growth of nitrobenzene-degrading bacteria. Therefore, biostimulation is a cost-effective and feasible bioremediation technique for nitrobenzene-contaminated groundwater.
    Synthesis and Herbicidal Activity of 5-Heterocycloxy-3-substituted-1-(3-trifluoromethyl)phenyl-1H-pyrazole
    XU Han, HU Xu-hong, ZOU Xiao-mao, ZHU You-quan, LIU Bin, HU Fang-zhong, YANG Hua-zheng
    2012, 28(5):  824-827 . 
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    The authors synthesized a series of novel 5-heterocycloxy-3-substituted-1-(3-trifluoromethyl)phenyl-1H- pyrazole derivatives. Herbicidal activities of the two intermediate compounds and thirteen target compounds were evaluated via Brassica napus and Echinochloa crusgalli(L.) Beauv tests. Bioassay results show that some of the compounds exhibit better inhibiting activities against Brassica napus and some of the compounds exhibit bleaching activities against Echinochloa crusgalli(L.) Beauv at 100 μg/mL.
    Synthesis and Electrochemical Behavior of Electroactive Bistetrathiafulvalene-attached Thiacalix[4]arene Assemblies
    ZHAO Bang-tun, LI Jia-jia, ZHOU Zhen, YAN Zhen-ning, ZHU Wei-min
    2012, 28(5):  828-832 . 
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    Tetrabromoalkylthiacalix[4]arenes(1a and 1b) reacted with excess bis(tetraethylammonium)-bis(1,3- dithiole-2-thione-4,5-dithiol)zincate(2) to give thiacalix[4]arene-thiones(3a and 3b) in the presence of Na2S. Two novel bistetrathiafulvalene-attached thiacalix[4]arene assemblies(5a and 5b) formed via triethyl phosphite-mediated cross-coupling of thiacalix[4]arene-thiones(3a and 3b) and 4,5-biscyanoethylthio-1,3-dithiole-2-one(4). All the four new compounds were characterized by 1H NMR, 13C NMR, IR, MS spectra and elemental analysis. Meanwhile, the structures of thiacalix[4]arene-thiones(3a and 3b) were identified by X-ray analysis. In addition, the cyclic voltammograms of the resulting thiacalix[4]arenes containing electroactive TTF units(5a and 5b) were provided.
    Improved Method for Lacosamide Synthesis with Chemoenzymatic Method
    WANG Zhi-yuan, XU Li-sheng, LIU Jun-zhong, ZHANG Hong-juan, GAO Ji, LIU Qian, JIAO Qing-cai
    2012, 28(5):  833-836 . 
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    Lacosamide was prepared by chemical method coupled with enzymatic method. N-Acetyl-D, L-3-methoxy-alanine, derived from D,L-3-methoxy-alanine, was used in the resolution process catalyzed by immobilized Escherichia coli cells with aminoacylase(EC3.5.1.14) activity. N-Acetyl-D-3-methoxy-alanine and L-3- methoxy-alanine were obtained from the resolution system. Lacosamide was synthesized by the amidation of N-acetyl-D-3-methoxy-alanine with benzylamine.
    Synthesis, Crystal Structure and Biological Activites of Rotenone O-Alkyl Oximes
    CHEN Xiao-dong, WANG Chao, HU Ai-xi, YE Jiao, ZHANG Cui-yang
    2012, 28(5):  837-842 . 
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    A series of rotenone O-alkyl oxime derivatives was designed and synthesized. Their structures were confirmed by elemental analyses, Fourier transform infrared(FTIR) and 1H NMR spectral studies, and the typical crystal structure of rotenone O-ethyl oxime(3b) was determined by X-ray diffraction. The preliminary biological activities of the new compounds were evaluated. The results of bioassays indicate that the title compounds exhibit moderate insecticidal and bactericidal activities. Among the synthesized compounds, compound 3q exhibited 90.0% mortality against M. separata at 1000 μg/mL. Compounds 3b and 3g exhibited both 90.0% inhibition rate against R. solani at 500 μg/mL, respectively.
    Flexible Synthesis of Enantiomeric and Racemic 3-Hydroxymethyl-1,2,3,4-tetrahydroisoquinolines via Bischler-Napieralski Reaction
    KANG Chuan-qing, DU Zhi-jun, WANG Lan-lan, CHEN Yu, QIU Xue-peng, GUO Hai-quan, GAO Lian-xun
    2012, 28(5):  843-846 . 
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    With methyl ester of N-acylated L-3-(3,4-dihydroxyphenyl)alanine(L-DOPA) as starting material, racemic derivatives of 3-hydroxymethyl-1,2,3,4-tetrahydroisoquinoline were obtained with cyclization by Bischler-Napie- ralski(BN) reaction followed by reduction of methyl ester group to hydroxymethyl, while the optical pure enantiomers were prepared by the reduction of the methyl ester group to hydroxymethyl prior to cyclization with BN reaction. Racemerization took place in the BN stage in the presence of methyl ester, an electron-withdrawing group adjacent to chiral center. Therefore, the sequence of synthetic stages of cyclization and reduction, and subsequently whether there is electron-withdrawing group or not determines the chiral optical activity of the products.
    Efficient Synthesis of Complex Bridged 1,3-Oxazabicycles via Reactions of N-Alkyl-1,10-phenanthrolinium Halides with Cyclic 1,3-Diketones
    WU Ping, HUI Li, GAO Xing, YAN Chao-guo
    2012, 28(5):  847-850 . 
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    Complex bridged 1,3-oxazabicycles and 1,4-disubstituted 1,10-phenanthroline derivatives were efficiently prepared by the reactions of N-methyl or N-benzylphenanthrolinium halides with cyclic 1,3-dicarbonyl compounds in a K2CO3/CH3CN system.
    Expression and Characterization of a Thermostable Acyl-peptide Releasing Enzyme ST0779 from Sulfolobus tokodaii
    LI Rong, ZHANG Fei, CAO Shu-gui, XIE Gui-qiu, GAO Ren-jun
    2012, 28(5):  851-855 . 
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    Acyl-peptide releasing enzyme(AARE) belongs to a serine peptidase family and catalyzes the NH2-terminal hydrolysis of Nα-acylpeptides to release Nα-acylated amino acids. ORF0779(ORF=open reading frame) from thermophilic archaea Sulfolobus tokodaii(ST0779) was cloned and expressed in E. coli BL21 and the expressed protein was identified as a thermostable AARE. The target protein could be optimally overexpressed in E. coli at 30 ℃ for 8 h with 0.1 mmol/L isopropyl β-dthiogalactoside(IPTG). The crude enzyme was heated at 70 ℃ for 30 min, and then the target protein could account for above 40% of the total protein. The purification fold was 27 and the enzyme showed both esterase activity and peptidase activity. The optimal temperature and pH for ST0779 were 70 ℃ and 8.0 when Ac-Ala3 was used as substrate. The half-life of the enzyme(0.2 mg/mL) at 90 ℃ was about 16 h, indicating that the enzyme exhibits a favorable thermostability. The activity of ST0779 could still remain over 85% after being treated at 25 ℃ in different buffers with pH range from 6.0 to10.0 for 24 h, which indicates ST0779 is stable in neutral or slight alkali environment. Under neutral or slightly alkali conditions, the enzyme exhibits really high catalytic efficiency against acyl-peptide, and the optimal substrate is Ac-Ala3. Most metal ions have no inhibition effect on the activity of ST0779, while 4% activity of ST0779 is inhibited in the presence of K+. This enzyme was supposed to be applied in the analysis of protein sequencing and the synthesis of small peptides.
    Knockdown of STAT3 by iRNA Inhibiting Migration and Invasion of Epithelial Ovarian Cancer Cells
    LI Qin-hua, ZHU Ji-hong, LIU Lei, YUE Ying
    2012, 28(5):  856-861 . 
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    Signal transducer and activator of transcription 3(STAT3) is a dual functional transcription factor with the functions of signal transduction and transcription regulation. It is reported that the expression of STAT3 in ovarian cancer is significantly higher and STAT3 can facilitate ovarian cancer growth and metastasis. To clarify the definite effect and molecular mechanism of STAT3 involved in ovarian cancer growth and metastasis, STAT3 expression was significantly downregulated by transfecting ovarian cancer model SK-OV-3 cells with the plasmid vector which express specific RNAi that targets human STAT3. The downregulated STAT3 not only decreased the invasion and migration but also inhibited the proliferation of SK-OV-3 cells. Western blot assay shows that the expression of vascular endothelial growth factor(VEGF) and that of Survivin were reduced in the cells with the plasma vector expressing specific RNAi that targets human STAT3. These results demonstrate that STAT3 involved in the invasion and migration of SK-OV-3 regulates the expression of VEGF and Survivin. In addition, VEGF and Survivin could play an important role in ovarian cancer growth and metastasis.
    Inhibition of α/β-K6P2W18O62·10H2O on the Activity of Mushroom Tyrosinase and Its Antimicrobial Effects
    HU Xi-yu, CHEN Bing-nian, WANG Li, CHEN Fa-he
    2012, 28(5):  862-865 . 
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    Dawson-type phosphotungstic polyoxometalate α/β-K6P2W18O62·10H2O(P2W18) was synthesized and its inhibitory effect on the mushroom tyrosinase was investigated. It could inhibit diphenolase activity of mushroom tyrosinase as an irreversible inhibitor. When the concentration of the enzyme reached 0.0176 mg/mL, the concentration of P2W18 leading to 50% activity lost(IC50) was 0.05 mmol/L for monophenolase and 0.64 mmol/L for diphenolase. In addition, the antimicrobial activity of P2W18 was evaluated by zone of inhibition test. The results show that P2W18 possesses effective antimicrobial ability against Escherichia coli, Bacillus subtilis, yeast, especially Escherichia coli and yeast.
    Effect of SO2 on Performance of Solid Oxide Fuel Cell Cathodes
    WANG De-jun, LENG Jing
    2012, 28(5):  866-868 . 
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    Effects of SO2 in ambient air on the performance and durability of solid oxide fuel cell(SOFC) cathode were evaluated by galvanostatic measurement. Comparison between two cathode materials was made to consider the cathode degradation mechanisms. The degradation performance is associated with a slow decomposition of the La0.6Sr0.4Co0.2Fe0.8O3(LSCF) due to the segregation of strontium oxide. Negligible deterioration for (La0.7Sr0.3)MnO3 (LSM) cathode was caused by SO2 poisoning under a current density of 200 mA/cm2. Metal sulphate formation may explain a slight deterioration under increasing high the concentration of SO2. It was verified that the poisoning mechanism for the two cathode materials resulted from the gradual decomposition of the cathode materials.
    Hybrid Electrochromic Multilayer Films Based on Fe(II)-Metalloviologens and TiO2 Nanoparticles
    WANG Rui, LIU Dong-xu, YANG Yang, YU Da-hui, YAO Wei-guo, DENG Chang-chun, DONG Wen-fei
    2012, 28(5):  869-873 . 
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    Metallosupramolecular coordination polyelectrolyte, Fe(II)-metalloviologen(FEN), was prepared by the reaction of Fe(II) with a novel bisterpyridine ligand. As active components, FENs could be assembled into electrochromic multilayer films with negative charged polystyrene sulfate(PSS) by the sequential deposition layer-by-layer technique. Numerous analytical instruments, such as UV-Vis spectroscopy, atomic force microscopy(AFM), tunneling electron microscopy(TEM), zeta-potential measurement and electrochemical measurement have been utilized to characterize their morphology, optical and electrochromic properties. It has been observed that as-prepared films exhibited multi-colour changes by triggering with different potentials. However, the low optical contrast of multilayer films would limit their further applications. In order to overcome this problem, semiconductor TiO2 nanoparticles(TiO2) were incorporated into FEN multilayers by layer-by-layer approach. By carefully optimizing the film structure, as-resulted hybrid films containing FEN, TiO2 and PSS exhibited high optical contrast, suitable response time and long-term stability. Such hybrid films should be promising candidates to meet the requirements for deve- loping flexible displays and electrochromic devices.
    Manganese Dioxide with High Specific Surface Area for Alkaline Battery
    HUANG You-ju, LIN Yu-li, LI Wei-shan
    2012, 28(5):  874-877 . 
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    The authors reported a facile method for the synthesis of manganese dioxide without any template and catalyst at a low-temperature. The prepared sample was characterized with X-ray diffraction(XRD), scanning electron microscopy(SEM), Brunauer-Emmett-Teller(BET) surface analysis, Fourier transform infrared(FTIR) spectrometry, cyclic voltammetry, alternative current(AC) impedance test and battery discharge test. It is found that the prepared sample belongs to α-MnO2 and has a microsphere morphology and a large BET surface area. The electrochemical characterization indicates that the prepared sample displays a larger electrochemical capacitance than the commercial electrolytic manganese dioxides(EMD) in Na2SO4 solution, and exhibits larger discharge capacity than EMD, especially at a high rate discharge condition when it is used as cathode of alkaline Zn/MnO2 battery.
    Non-isothermal Decomposition Kinetics of K(AHDNE)
    L?Lei, XU Kang-zhen, QIU Qian-qian, WANG Gang, SONG Ji-rong, ZHAO Feng-qi
    2012, 28(5):  878-881 . 
    Abstract ( )   PDF (228KB) ( )  
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    The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitro- ethylene potassium salt[K(AHDNE)] were studied under the non-isothermal conditions by different scanning calorimeter(DSC) method. The thermal behavior of K(AHDNE) presents three exothermic decomposition processes. The kinetic equation of the first thermal decomposition reaction obtained is dα/dT=(1019.63/β)3(1-α)[-ln(1-α)]2/3exp(-1.862× 105/RT). The self-accelerating decomposition temperature(TSADT) and critical temperature of thermal explosion(Tb) of K(AHDNE) are 162.5 and 171.4 ℃, respectively. K(AHDNE) has higher thermal stability than AHDNE.
    Ruthenium Nanoparticles Loaded on Carbon as Effective Catalyst for Highly Selective Hydrogenation of 4,4′-Methylenedianiline
    DU Wen-qiang, RONG Ze-ming, LU Xin-yi, WANG Yi-fan, LU Lian-hai, QU Jing-ping
    2012, 28(5):  882-885 . 
    Abstract ( )   PDF (383KB) ( )  
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    Supported Ru-based catalysts, prepared by a surfactant-stabilized colloidal method, exhibited a good selectivity to bis(4-aminocyclohexyl)methane via the hydrogenation of 4,4′-methylenedianiline. Transmission electron microscopy(TEM) and X-ray diffraction(XRD) characterization showed Ru nanoparticles were well-dispersed on activated carbon, leading to the high activity and selectivity to the product.
    Photo-isomerization of Aromatic α-Hydroxy Hydrazone
    JIN Jing-yi, PAN Yan, LI Xiu-hua, HOU Jun, WU Xue, SU Zhong-min
    2012, 28(5):  886-890 . 
    Abstract ( )   PDF (347KB) ( )  
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    Photo-isomerization of aromatic α-hydroxy hydrazone was reported. We investigated the structures of salicylaldehyde phenylhydrozone(SP) in the ground state using density functional theory(DFT) with the B3LYP functional and the 6-311+G(d) basis set. All nine possible isomers of SP in the ground state consist of seven phenol forms and two ketone forms. Intrisic reaction coordinate(IRC) analysis discloses the existence of a cycle driven by the two proton transfer processes in the ground and excited states of SP, which suggests that no ketonic form could exist in the ground state. Further theoretical studies of the potential energy surfaces support a trans-cis conversion followed by a relaxation to the stable form of SP in the excited states.
    Electrochemical Degradation of o-Chloronitrobenzene by Three-dimensional Electrodes
    MENG Qing-han, WANG Jing, LIU Ling, CAO Bing
    2012, 28(5):  891-896 . 
    Abstract ( )   PDF (276KB) ( )  
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    Degradation of o-chloronitrobenzene wastewater was experimentally investigated at a three-dimensional electrode(TDE) with granular activated carbon as the particle electrode, graphite as the anode, and stainless steel plate as the cathode. The kinetic model of o-chloronitrobenzene degradation was studied, and the effects of pH, electrolysis time, particle electrode, electrolyte concentration, and initial concentration of the solution on degradation efficiency were investigated to determine the optimal operating conditions. The degradation of o-chloronitrobenzene by oxidation at the TDE was monitored by chemical oxygen demand(COD) measurements, UV-Vis absorption, and high performance liquid chromatography(HPLC). COD degradation by electrochemical degradation followed pseudo-first order kinetics with respect to the concentration of o-chloronitrobenzene solutions. Optimal reaction conditions included 15 g of activated carbon as the particle electrode, 400 mg/L o-chloronitrobenzene solution containing 0.10 mol/L Na2SO4, pH=3, and 60 min of electrolysis. The UV-Vis absorption spectra and HPLC results illustrate that the benzene ring in o-chloronitrobenzene was rapidly broken down to form aliphatic substances through electrochemical degradation. COD degradation was approximately 98.5% at optimal conditions.
    Influence of Isotope Effects on Product Polarizations of N(2D)+D2, N(2D)+H2 and N(2D)+HD Reactive Systems
    NIE Shan-shan, CHU Tian-shu
    2012, 28(5):  897-902 . 
    Abstract ( )   PDF (378KB) ( )  
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    To figure out the influence of isotope effect on product polarizations of the N(2D)+D2 reactive system and its isotope variants, quasi-classical trajectory(QCT) calculation was performed on Ho’s potential energy surface(PES) of 2A″ state. Product polarizations such as product distributions of P(θr), P(φr) and P(θr,φr), as well as the generalized polarization-dependent differential cross sections(PDDCSs) were discussed and compared in detail among the four product channels of the title reactions. Both the intermolecular and intramolecular isotope effects were proved to be influential on product polarizations.
    Fabrication of Superhydrophobic Aluminum Plate by Surface Etching and Fluorosilane Modification
    YIN Shi-heng, ZHU Bin, LIU Yun-chun, YANG Ji, KUANG Tong-chun
    2012, 28(5):  903-906 . 
    Abstract ( )   PDF (313KB) ( )  
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    Superhydrophobic aluminum surfaces with a high water contact angle and low sliding angle on aluminum plate substrate were fabricated by means of surface etching with sodium hydroxide under ultrasonic bathing and then modification with fluorosilane. Scanning electron microscopy(SEM) showed a honeycomb-like structure on aluminum substrate surface after etching under ultrasonic bathing. And the surface was rendered from superhydrophilicity to superhydrophobicity after further modification with fluorosilane.
    Evaluation of Stabilization Performances of Antioxidants in Poly(ether ether ketone)
    ZHOU Zheng, ZHOU Fu-gui, ZHANG Shu-ling, MU Jian-xin, YUE Xi-gui, WANG Gui-bin
    2012, 28(5):  907-911 . 
    Abstract ( )   PDF (200KB) ( )  
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    Two types of antioxidants(a primary antioxidant and a secondary antioxidant) were used to improve the stability of poly(ether ether ketone)(PEEK). The effects of the antioxidants on the properties of PEEK and the stabilization mechanism were investigated by some characterization methods, such as rheometer, thermogravimetric ana- lysis(TGA), universal tester and electron spin resonance(ESR). The results indicate that the efficiency of the phosphorous antioxidant(DS) in improving the stability of PEEK was better than that of the phenolic antioxidant(DN) in both melting stability and thermal stability, and the thermal stability of PEEK sample containing 0.07%(mass fraction) DS was the best among all the samples due to the decrease of the free radicals density, as proven by ESR measurement. Additionally, no obvious changes could be observed in mechanical properties of PEEK containing antioxidants compared to those of virgin PEEK.
    Fabrication, Crosslinking and in vitro Biocompatibility of a Novel Degradable Nano-structure Urethral Tubular Scaffold
    WANG Xiao-qing, CHEN Qi-hui, HOU Yu-chuan, LU Zhi-hua, HU Jing-hai, ZHANG Hai-feng, HAO Yuan-yuan, ZHANG Long, GAO Zhan-tuan, WANG Chun-xi
    2012, 28(5):  912-915 . 
    Abstract ( )   PDF (378KB) ( )  
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    A degradable poly(lactic-co-glycolic acid, LA:GA=80:20)(PLGA) urethral tubular scaffold was fabricated by electrospinning. In order to enhance the mechanical properties, the scaffold was crosslinked with glutaraldehyde. The structure and properties of the crosslinked scaffolds were investigated by the mechanical property testing, scanning electron microscopy(SEM), degradability test in vitro and 3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-diphenytetrazo- liumromide(MTT). The results show that the scaffold has the nano-structure. The pore size and the porosity are suitable for cell seeding, growth and extracellular matrix production. Although influenced by the crosslinking slightly, the pore size and the porosity could still support cell proliferation and tissuse formation. The mechanical properties are remarkably increased by the crosslinking of glutaraldehyde, and it could meet the demands of a urethral stent. The scaffold could completely collapse within 70 d. The results of the biocompatibility test show that the PLGA scaffold had no cytotoxicity.
    Characterization of Nanostructures in Acellular Cementum of Human Tooth Roots
    GAO Yong-bo, LIU Ming-xia, SUN Zhi-qiang, ZHANG Kai, DONG Feng-xia, SUN Hong-chen, YANG Bai
    2012, 28(5):  916-920 . 
    Abstract ( )   PDF (969KB) ( )  
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    Determining the microstructure in human cementum might help us design new kinds of replacement materials for the treatment of teeth injury and disease. The authors characterized the nanostructures in the cementum of health human teeth via scanning electronic microscopy(SEM). It was found that the acellular cementum is mainly composed of two kinds of nanostructures―inorganic nanoparticles and organic nanofibers. And the inorganic nanoparticles show a tendency to arrange along the organic nanofibers. Based on the micro-molding in capillary strategy, the distribution of organic component in acellular cementum was copied with UV curable resin. After removing the inorganic nanoparticles by acid etching, many isolated spindle shape nanopores were left in polymer, which su- ggested that the inorganic nanoparticles should have been isolated by the organic component in cementum, and should be oval or nanosheet in shape. We hope the present work could provide reference for the biomimetic preparation of tissue engineering materials, and help us design new types of tooth implant.
    Chitosan-graft-poly(L-glutamic acid) Hybrid Material and Its Self-assembly
    LIU Ye-zhuo, YAO Jin-rong, CAO Heng, LENG Bo-xun, SHAO Zheng-zhong, CHEN Xin
    2012, 28(5):  921-925 . 
    Abstract ( )   PDF (283KB) ( )  
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    Chitosan-graft-poly(L-glutamic acid)(CS-g-PGA) copolymer was successfully synthesized by grafting polymerization of γ-benzyl-L-glutamate N-carboxyanhydride onto the modified chitosan chains. The self-assembly behavior of such a CS-g-PGA amphiphilic copolymer was studied. The results show that spherical nanoparticles have been formed. The size of CS-g-PGA nanoparticles is found to be controlled by the grafting ratio of PGA. These bio-based polysaccharide/polypeptide hybrid nanoparticles with controllable size may have great potential application in biomedical fields, such as drug delivery systems.
    Influence of Steric Hindrance Between Hydrogen Atoms of Linkage Groups and Adjacent Phenyls on Properties of Polyimide
    PANG Yu-wei, LUO Long-bo, CHEN Yi, ZHANG Peng, WANG Xu, PENG Chao-rong, LIU Xiang-yang
    2012, 28(5):  926-930 . 
    Abstract ( )   PDF (295KB) ( )  
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    A diamine monomer 4,4′-methylenedianiline(MDA) was introduced to modify the polyimide of pyromellitic dianhydride(PMDA) and 4,4′-oxydianiline(ODA) by polycondensation. A series of polyamic acids was synthesized from MDA and ODA of different molar ratios with PMDA of sum mole of moles of MDA and ODA, and polyimide films were obtained by thermal imidization. Polyimide(PI) films were characterized by tensile testing, dynamic mechanical analysis(DMA), thermal gravimetry analysis(TGA), Fourier transform infrared spectroscopy (FTIR), wide X-ray diffraction(WAXD) and molecular simulation. With the increase of MDA content, the tensile strength and thermal decomposition temperature remained generally stable compared with those of PMDA/ODA polyimide. Unexpectedly, the glass transition temperature(Tg) and Young’s modulus increased from 388.7 ℃ and 2.37 GPa to 408.3 ℃ and 5.74 GPa, respectively. The results of WAXD and molecular simulation indicate the steric hindrance among hydrogen atoms of the linkage groups and adjacent phenyls enhanced the properties of the polyimide modified with MDA.
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Jihong YU
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