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25 March 2012, Volume 28 Issue 2

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Cover and Content of Chemical Research in Chinese Universities Vol.28 No.2(2012)

2012, 28(2):  0-0. 

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Articles

Structure Analysis of Needle-like Copper Tantalum Trisulfide Crystals by XPS and Raman Spectroscopy

CHENG Dan, JIN Hua, LI Ben-xian, WANG Xiao-feng, CHU Qing-xin, Lü Yang, LIU Xiao-yang, ZHAO Xu-dong

2012, 28(2):  171-175 . 

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High-quality needle-like CuTaS3 single crystals have been synthesized through a chemical vapor transport(CVT) process. Crystallographic data show the special double chains of edge-sharing TaS₆ octahedra. The detailed XPS analysis of CuTaS₃ was undertaken and the valence states can be described by Cu⁺Ta⁵⁺3S^2–. In addition, CuTaS₃ crystals were characterized with Raman spectroscopy.



Preparation of Multilayered 1,2-Ethylene-silica Nanotubes Through a Dual-templating Approach

WU Li-min, BI Li-feng, WANG Si-bing, LI Bao-zong, LI Yi, YANG Yong-gang

2012, 28(2):  176-179 . 

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Multilayered 1,2-ethylene-silica nanotubes were prepared with cetyltrimethylammonium bromide(CTAB) as a template and (S)-β-citronellol(CN) as a co-structure-directing agent. For a better understanding of the formation of this structure, the CN/CTAB molar ratio in the reaction mixtures was tuned. With increasing the CN/CTAB molar ratio, a hexagonal to lamellar phase trasformation was observed; and the morphologies of 1,2-ethylene-silica changed from rod to vesicle and then to tubular structure. CN droplets were proposed as the templates for the nanotubes. The obtained samples were characterized by means of X-ray diffraction, nitrogen sorption, field emission scanning electron microscopy and transmission electron microscopy.



Regulation of Microstructure of Calcium Carbonate Crystals by Egg White Protein

ZHU Wen-kun, LUO Xue-gang, ZHANG Chi, DUAN Tao, ZHOU Jian

2012, 28(2):  180-185 . 

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Crystal growth of calcium carbonate in biological simulation was investigated via egg white protein with different volume fractions, during which calcium carbonate was synthesized by calcium chloride and sodium carbonate. The morphology, thermal properties and microstructure of the calcium carbonate micro-to-nanoscale crystals were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TG) and X-ray diffraction(XRD) analysis. The results show that the volume fraction of egg white protein has great influence on the shape, size and morphology of calcium carbonate crystals. The calcium carbonate crystals were the mixtures of calcite-vaterite-like crystals including spherical and rough surface, which are different from that formed in pure water. With the increase of egg white protein concentration, the diameter of calcium carbonate crystals changed, the amount of formed spherical calcium carbonate particles decreased and that of vaterite increased. These results indicate that the coordination and electrostatic interaction between egg white protein and Ca²⁺ significantly affect the calcium carbonate crystalization.



Synthesis, Structure and Characterization of Three Metal Molybdate Hydrates: Fe(H₂O)₂(MoO₄)₂·H₃O, NaCo₂(MoO₄)₂(H₃O₂) and Mn₂(MoO₄)₃·₂H₃O

YU Yang, LIU Dan, HU Wei-wei, LI Jia, PENG Yu, ZHOU Qi, YANG Fen, LI Guang-hua, SHI Zhan, FENG Shou-hua

2012, 28(2):  186-190 . 

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Three metal molybdate hydrates, Fe(H₂O)₂(MoO₄)₂·H₃O(FeMo), NaCo₂(MoO₄)₂(H₃O₂)(CoMo) and Mn₂(MoO₄)₃·2H₃O(MnMo), were synthesized by the mixed-solvent-thermal methods and characterized by single- crystal X-ray diffraction. X-Ray photoelectron spectroscopy and bond-valence sums were applied to confirming the valance of Fe, Co, Mn and Mo. Thermo-gravimetric analysis and X-ray powder diffraction measurements indicate that the samples were converted to different structural compounds upon heating in air at 600 °C for 1 h. The magnetic properties of these compounds were studied. The dominant magnetic interactions are antiferromagnetic in nature. However, different synthesis conditions led to the diversity of magnetic properties of compound CoMo.



Determination of Sex Hormones in Antler Velvet by High Performance Liquid Chromatography Tandem Mass Spectrometry

LU Chun-mei, WANG Ming-tai, MU Jun, BAI Yu-ping, DU Jian-shi, ZHANG Han-qi, WANG Jian-wei

2012, 28(2):  191-194 . 

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Eighteen sex hormones in antler velvet were determined by high performance liquid chromatography tandem mass spectrometry. The solid phase extraction was applied to eliminating the matrix effect. The experimental conditions were examined and optimized. Under the optimal conditions, the proposed method provides the good linearities and determination limits(0.2―1.0 μg/kg) of the analytes investigated. The recoveries ranging from 72.3% to 149.5% were obtained for the target analytes at two concentration levels. This method was applied to the determination of eighteen sex hormones in different kinds of antler velvet samples and the obtained results are satisfactory. The results indicate that the proposed method is suitable for the determination of sex hormones in antler velvet samples.



Investigation of Breaking Efficiency of N-Glycosidic Bond Between Sulfonamide and Honey

WANG Yan-hua, LI Li, CHEN Chia-hung, CHENG Shuenn-ren, LEE Mu-sheng, YU Pu-ping, CHANG-CHIEN Guo-ping

2012, 28(2):  195-199 . 

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Sulfonamide residue in honey existed in a form bonded to sugar via the N-glycosidic bond. It would result in the possible underestimation of concentration of sulfonamide if it is not decomposed by chemical methods. However, in Mainland China and Taiwan(P. R. China), the regulation for sulfonamide residue analysis does not include hydrolysis and has been applied to a very broad range of samples, for example, egg, milk, meat, seafood as well as honey. This paper demonstrates the necessity of hydrolysis of it prior to extracting honey. The breaking efficiencies of N-glycosidic bond were investigated by 2 mol/L hydrochloric acid, pure methanol and 0.5 mol/L hydrochloric acid in methanol, respectively. It was found that acid plays the key role in breaking the N-glycosidic bond, and it was also noticed that the dissolution of liberated sulfonamide in methanol could carry the reaction forward in favor of breaking the N-glycosidic bond.

Fast Screening of Chicken Egg Lysozyme in White Wine Products by Extractive Electrospray Ionization Mass Spectrometry

ZHOU Zhi-quan, JIANG Jie, LI Ming, ZHAO Zhan-feng, FU Jun

2012, 28(2):  200-203 . 

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Fast detection of trace lysozyme, one of the most important food allergens in white wine samples, was achieved by extractive electrospray ionization mass spectrometry without sample pretreatment in this study. The multiply-charged ions of m/z 1587 were chosen for the quantitative detection of lysozyme in white wine, showing linear dynamic signal responses in a range of 5―75 μg/mL with a linearity coefficient of 0.999 and an acceptable relative standard deviation(RSD) of 8.0%―15.0% for directly measuring lysozyme in the complex food samples. The limit of detection for lysozyme in white wine sample was calculated to be 5 μg/mL, which was lower than the amounts that can provoke allergic reactions(oral test with 3 mg or labial test with 1 mg/mL). A single sample analysis was completed within 1 min. The data demonstrate that extractive electrospray ionization mass spectrometry is a useful tool for fast screening lysozyme in the complex matrix, showing promising application in the rapid detection of food allergen.



Source Apportionment of Ambient PM₁₀ in the Urban Area of Longyan City, China: a Comparative Study Based on Chemical Mass Balance Model and Factor Analysis Method

QIU Li-min, LIU Miao, WANG Ju, ZHANG Sheng-nan, FANG Chun-sheng

2012, 28(2):  204-208 . 

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In order to identify the day and night pollution sources of PM₁₀ in ambient air in Longyan City, the authors analyzed the elemental composition of respirable particulate matters in the day and night ambient air samples and various pollution sources which were collected in January 2010 in Longyan with inductivity coupled plasma-mass spectrometry(ICP-MS). Then chemical mass balance(CMB) model and factor analysis(FA) method were applied to comparatively study the inorganic components in the sources and receptor samples. The results of factor analysis show that the major sources were road dust, waste incineration and mixed sources which contained automobile exhaust, soil dust/secondary dust and coal dust during the daytime in Longyan City, China. There are two major sources of pollution which are soil dust and mixture sources of automobile exhaust and secondary dust during the night in Longyan. The results of CMB show that the major sources are secondary dust, automobile exhaust and road dust during the daytime in Longyan. The major sources are secondary dust, soil dust and automobile exhaust during the night in Longyan. The results of the two methods are similar to each other and the results will guide us to plan to control the PM₁₀ pollution sources in Longyan.



Toxicity of Nanoscale CuO and ZnO to Daphnia magna

ZHAO Hai-zhou, LU Guang-hua, XIA Jun, JIN Shao-ge

2012, 28(2):  209-213 . 

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The potential effects of nanoscale CuO(nCuO), nanoscale ZnO(nZnO) and their mixtures on Daphnia magna were investigated, including 48-h acute toxicity and 21-d chronic toxicity tests as well as a feeding experiment. The results of acute toxicity show that nCuO/nZnO mixture was the most toxic followed by nCuO and nZnO. The nanoparticles(NPs) inhibited both the growth and reproduction of Daphnia magna during the testing period. Concentration dependence was apparent in all the cases and the intrinsic rate of natural increase was confirmed to be a very sensitive parameter to NPs exposure. Binary mixture appeared to be more toxic than the corresponding individual exposures at most cases except for the feeding behavior.



Synthesis and Anti-tumor Activity of Novel Glycyrrhetinic Acid Derivatives

MENG Yan-qiu, DING Jia-qi, LIU Yuan, NIE Hui-hui, GUAN Sai, ZOU Chao, ZHAO Na, CHEN Hong, CAO Bo

2012, 28(2):  214-219 . 

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Twenty-five derivatives of glycyrrhetinic acid(GA) modified on the A-ring, at C30 and C11 positions were synthesized. Their in vitro cytotoxicity against various cancer cell lines[henrietta lacks strain of cancer cells(HeLa), human hepatocellular liver carcinoma cells(HepG2) and human gastric carcinoma cells(BGC-823)] was evaluated by standard MTT[3-(4,5-dimethyl-2-thiazol-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay. All the tested derivatives were found to have stronger cell growth inhibitory than their parent compound GA. Among them, compounds 3a, 5a, and 8d have similar activity on HeLa cell line, and compound 8a has similar activity on HeLa, HepG2 and BGC-823 cell lines as Gefitinib.



Sono-chemical Synthesis and Mechanism of Dibenz[a,c]anthracene

MUDDASIR Hanif, WANG Zhi-ming, LU Ping, MA Yu-guang

2012, 28(2):  220-224 . 

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Planar polycyclic aromatic hydrocarbons have important applications in optoelectronics, environmental chemistry and cancer researches. An improved sono-chemical synthetic procedure of dibenz[a,c]anthracene(D[a,c]A) was reported in this work. The yield was increased to 56% and the resultant was carefully characterized via gas chro- matography-electron impact mass spectrometry(GC-EIMS), matrix assisted laser desorption ionization-time of flight (MALDI-TOF), ¹H NMR, ¹³C NMR, correlation spectrometry(¹H-¹H COSY), heteronuclear multiple bond correlation(HMBC) and heteronuclear multiple quantum coherence(HMQC). Based on the characterization data, we proposed a 4-step mechanistic explanation for the formation of D[a,c]A under sono-chemical bis-ortho-Wittig reaction conditions.



Acylation of Quercetin with a Novel Thermophilic Esterase as Biocatalyst

XIE Xiao-na, ZHANG Chun-li, XUN Er-na, WANG Jia-xin, ZHANG Hong, WANG Lei, WANG Zhi

2012, 28(2):  225-229 . 

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The regioselective acylation of quercetin catalyzed by a novel thermophilic esterase(APE1547) from the archaeon Aeropyrum pernix K1 was successfully conducted in organic solvents. The effects of acyl donor, substrate ratio, organic solvent, temperature, and water activity were investigated. Under the optimum conditions, a yield of 74% for its mono ester could be achieved in the reaction for about 6 h. With the reaction time extending to about 30 h, the final conversion of quercetin was about 100% and three products were synthesized.



Synthesis, Crystal Structure and Thermal Analysis of N-(2,3-Dimethyl-phenyl)-N′-(methoxyl formyl)thiourea

ZHAO Dan, HUANG Jie, SONG Ji-rong, ZHONG Yi-tang, WANG Li-qin, HE Jian-yun

2012, 28(2):  230-233 . 

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N-(2,3-Dimethyl-phenyl)-N′-(methoxyl formyl)thiourea was synthesized by the reacting of 2,3-dimethy- laniline, potassium thiocyanate(KSCN) and methyl chloroformate(ClCOOCH₃). Single crystal was obtained by slowly evaporation solvent at room temperature. The structure was characterized by elemental analysis, IR and X-ray crystalography. The compound crystallized: a triclinic system with space group Pī, a=0.83440(12) nm, b=0.89113(13) nm, c=0.93015(13) nm, α=76.548(2)°, β=63.906(2)°, γ=82.538(2)°, V=0.60379(15) nm³, Z=2, D_c=1.311 mg/m³, F(000)=252, μ=0.256 mm^-1, R₁=0.0379, wR₂=0.0919. The specific heat capacity of the title compound was determined by a Micro-DSC method, and the specific heat capacity was 1.25 J·g^-1·K^-1 at 298.15 K. Thermodynamic functions, relative to those at the standard temperature of 298.15 K, were calculated via thermodynamic relationship. The thermal behavior of the title compound under a non-isothermal condition was studied by differential scanning calorimetry/thermogravimetric(DSC/TG) method. There was an obvious endothermic peak in the DSC curve, the peak temperature was 479.43 K. The compound mass loss was 89.94% observed from the TG curve.



Facile Synthetic Method and Crystal Structure of 2, 3, 3′, 4′-Biphenyltetracarboxylic Dianhydride

YI Shi-xu, GAO Guo-wei, YANG Mei-jia, CHEN Hua, WU Di-feng, MEN Jian

2012, 28(2):  234-238 . 

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A facile method for the synthesis of 2,3,3′,4′-biphenyltetracarboxylic dianhydride(a-BPDA) was reported, which comprises the steps of the dehalogenative coupling of dimethyl 4-chlorophthalate(4-DMCP) and dimethyl 3-chlorophthalate(3-DMCP) catalyzed by low-cost (Ph₃P)₂NiCl₂, the hydrolysis of tetra-ester and the dehydration of tetra-acid. In contrast to the conventional methods, this method has the advantage of low cost, convenient manipulation, available condition, high purity and good overall yield. Moreover, the single crystal structure of a-BPDA was analyzed by X-ray diffraction method. The X-ray data suggest that a-BPDA is a rigid, non-coplanar and non-linear structure. It contains three crystallographically independent molecules, in which the dihedral angles of the two linked phenyl rings are 44.75(4)°, 46.37(3)° and 42.32(3)°, respectively. The title molecule is governed by a stronger intermolecular interaction in contrast to van der Waals interaction because of the special positions of anhydride groups.



Design, Synthesis and Electrochromic Properties of Anthraquinone Imide-based Donor-acceptor Type of Near Infrared Chromophores

QIAO Wen-qiang

2012, 28(2):  239-241 . 

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A new series of near infrared(NIR) electrochromic anthraquinone imides containing a triphenylamine moiety as an electron donor was synthesized and their electrochemical and spectroelectrochemical behavior were investigated. The results show that the new anthraquinone imides are redox active which can be reduced electrochemically from the neutral state to the radical anion form that absorbs in a range of 700―1200 nm.



Aryl-guanidine/Pd-catalyzed Suzuki Cross-coupling Reaction at Room Temperature

LI Yan-chun, LIN Ying-jie, ZHANG Suo-bo, LI Sheng-hai, DUAN Hai-feng

2012, 28(2):  242-244 . 

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Four aryl-guanidines(AG) were synthesized and used for the palladium-catalyzed Suzuki cross-coupling reaction to test the catalytic activity. In the presence of steric bulk AG, when aryl bromide and arylboronic acid were used as the reactants, the Suzuki reaction could be carried out smoothly at room temperature in aqueous solvent to afford the cross-coupling product in high yield. This catalysis system was also successful for the coupling of activated aryl chlorides at room temperature.



Expression of Soluble Vascular Endothelial Growth Factor Receptor-2 and Its Effect on Proliferation of Vascular Endothelial Cells

WANG Song, Lü Jian-nan, XU Yan, LIU Lu-cheng, WU Jiang, SHAO Guo-guang, SUN Xin

2012, 28(2):  245-248 . 

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Vascular endothelial growth factors(VEGFs) respectively bind to each of three receptor tyrosine kinases (RTKs), known as Flt-1, KDR and Flt-4. Since VEGFs and their respective families of receptor tyrosine kinases (VEGFRs) are critical proteins which can regulate vascular development during angiogenesis, we decided to explore the inhibitory effects of soluble kinase insert domain-containing receptor(sKDR) on endothelial cells and angiogenesis. Total RNA was extracted from human umbilical vein endothelial cells(HUVEC), and cDNA of extracellular domains 1―4 was amplified and recombined with pQE40 vector. After being expressed, affinity purified, renatured and analyzed by Western blot, the sKDR was assayed for its effects on endothelial cells by [3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide](MTT), and on angiogenesis by chick chorioallantoic membrane(CAM) experiment. sKDR cDNA of 1150 bp was obtained via real-time polymerase chain reaction(RT-PCR), and sKDR was expressed by pQE40 procaryotic expression system, purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis with only one band and proved by Western blot. MTT assay demonstrateds that sKDR could inhibit the VEGF-stimulated HUVEC from proliferation, and CAM experiment showed sKDR could block the VEGF-induced angiogenesis. sKDR has the biological activity to bind with VEGF ligands and is a potential target for tumor anti-angiogenesis therapy.



Isolation, Purification and Bioactivities of Polysaccharides from Irpex lacteus

ZHANG Na, LIU Yan, LU Jia-hui, WANG Juan, YANG Shuang, ZHANG Nan, MENG Qing-fan, TENG Li-rong

2012, 28(2):  249-254 . 

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Irpex lacteus has been widely used for treating chronic glomerulonephritis as a traditional Chinese medicine. Seven water-soluble polysaccharide fractions(ILN I, ILN II, ILN III, ILA I, ILA II, ILB I and ILB II) were isolated and purified from Irpex lacteus by hot-water extraction, deproteinization, decolorization, dicthy laminoethyl(DEAE)-cellulose ion exchange and sephadex G100 chromatographies, respectively. The average molecular weights and monosaccharide composition of these polysaccharide fractions greatly differed from each other. The antitumor and antinephritis activities of the seven polysaccharide fractions were evaluated. It was found that ILN III displayed significant inhibition effects on both humar hepatocellular liver carcinoma(HepG2) and hentietta lacks(HeLa) tumor cells with IC₅₀ values of 60.95 and 99.95 μg/mL, respectively. ILA I exhibited significant inhibition effects on murine mesangial cells(HBZT-1) with an IC50 value of 185.06 μg/mL. The inhibition effects of other polysaccharide fractions on these three cells were significantly different. These results suggest that the polysaccharide fractions isolated from Irpex lacteus have potential antitumor and antinephritis activities.



Association of UCP3, APN, and TNF-α Gene Polymorphisms with Type 2 Diabetes in a Population of Northern Chinese Han Patients

WANG Ling-ling, DU Zhen-wu, LIU Jia-nan, WU Mei, SONG Yang, JIANG Ri-hua, ZHANG Gui-zhen

2012, 28(2):  255-258 . 

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We observed the polymorphism distribution and coaction of uncoupling protein 3(UCP3)-55C/T, adipo-nectin(APN)+45T/G and tumor necrosis factor(TNF)-α-308G/A on the onset and development of T2DM in a Northern Chinese Han population of 213[100 type 2 diabete(T2DM) patients and 113 health control subjects] by polymerase chain reaction-restriction fragment length polymorphisum(PCR-RFLP) method. Results demonstrate the polymorphism of UCP3-55C/T, APN+45T/G, and TNF-α-308G/A related to T2DM onset and developement. And the individuals carrying UCP3-55T, APN+45G and TNF-α-308A allele had higher T2DM risk. Those results are the first report to evaluate the association of the coaction of UCP3, APN, TNF-α genes polymorphism on T2DM risk and the susceptibility of T2DM in the Northern Chinese Han population.



Establishment of a Tumor-bearing Mouse Model Stably Expressing Human Tumor Antigens Survivin and MUC1 VNTRs

ZHANG Li-xing, DU Jian-shi, WANG Yu-qian, LIU Chen-lu, XIA Qiu, ZHANG Xi-zhen, CONG Xian-ling, ZHANG Hai-hong

2012, 28(2):  259-263 . 

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The eukaryotic vectors VR1012 expressing survivin or 33 tandem repeats of human mucin 1(MUC1) (VNTRs), namely, VR1012-S and VR1012-VNTR(VNTR=variable number of tandem repeat), were constructed by cloning survivin and VNTR genes into VR1012, respectively. The eukaryotic vector pEGFP expressing survivin and MUC1 VNTRs fusion gene pEGFP-MS was also constructed. Mouse melanoma cell line(B16) stably expressing survivin and MUC1 VNTRs(MS⁺B16) was established by Lipofectamine-mediated transfection of pEGFP-MS into B16 cells. EGFP expression in MS⁺B16 cells was observed using a fluorescent microscope and survivin and MUC1 VNTRs(MS) expression was confirmed by means of Western blot analysis. A syngenic graft tumor model was gene- rated by subcutaneous injection of MS⁺B16 cells into C57/BL6 mice and tumor size increased rapidly with time in a cell number dependent manner. After the third immunization, mice were challenged subcutaneously with 5×l0⁵ MS⁺B16 cells. Compared with that of the negative control immunized with phosphate-buffered saline(PBS), a signi- ficant reduction of tumor growth was observed in groups immunized with survivin plasmid DNA and MUC1 VNTRs plasmid DNA. Thus, the suppression of subcutaneous tumor was antigen-specific. This model is useful for the development of tumor vaccines targeting survivin and MUCI VNTRs.



Effect of HMGA2 shRNA on the Cell Proliferation and Invasion of Human Colorectal Cancer SW480 Cells In vitro

XU Guang-meng, ZHANG Hai-na, TIAN Xiao-feng, SUN Mei, FANG Xue-dong

2012, 28(2):  264-268 . 

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High mobility group A2(HMGA2) protein is a small nonhistone chromosomal protein that can modulate transcription of an ample number of genes. Many previous studies demonstrate that up-regulation of HMGA2 expression occurrs in many kinds of cancers including colorectal cancer, suggesting that HMGA2 might play a critical role in the progression of various tumors. However, the exact role of HMGA2 in colorectal cancer has not been determined. To verify the essential role of HMGA2 in the growth and invasiveness of colorectal cancer, HMGA2 expression was down-regulated by RNA interference(RNAi) in SW480 cells. We observed that the knockdown of HMGA2 led to the significant inhibition of proliferation and invasion of SW480 cells in vitro. These results suggest that HMGA2 might play a crucial role in the progression of colorectal cancer, and be a potential therapeutic target for human colorectal cancer.



Anticancer Effects of Fusion Protein CAtin on DMBA-induced Carcinogenesis in Buccal Pouch of Chinese Hamster

BAI Jie-ying, LI Xiao, LI Chang, ZHANG Xiao-fei, LI Zhi-xin, ZHAO Shuang, LIU Xiao, ZENG Lin, CHI Bao-rong

2012, 28(2):  269-275 . 

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Aberrant expression of carcinoembryonic antigen(CEA) is a common feature for multiple types of cancer, which makes it an attractive target for anticancer therapy. CAtin is a novel dual cancer-specific fusion protein, composed of an anti-CEA single-chain disulfide-stabilized Fv antibody(scdsFv) and Apoptin, a tumor-specific apoptosis-inducing protein. Oral squamous cell carcinoma(OSCC) is an important healthcare problem in the clinic. To evaluate the anticancer effects of CAtin on OSCC, 7,12-dimethylbenz[a]anthracene(DMBA) was used to induce oral carcinogenesis and premalignant lesions in the buccal pouch of Chinese hamster, and the antitumor effects of CAtin were determined in pre-cancer, cancer and post-operatative cancer models, respectively. The results show that the administration of CAtin delayed the malignant transformation of early stage cancerous lesions, inhibited the growth of established solid oral tumors and reduced the post-operatative relapse of lesions, with no significant systemic toxicity. This study demonstrates that CAtin may have potential for the treatment of OSCC, and the development of preventive strategies based on CAtin may offer a practical approach for the treatment of human oral tumors.



Cytotoxicity and DNA Damage Effect of TGA-capped CdTe Quantum Dots

LI Yan-bo, ZHANG Hai-xia, GUO Cai-xia, HU Gui-qin, DU Hai-ying, JIN Ming-hua, HUANG Pei-li, SUN Zhi-wei, YANG Wen-sheng

2012, 28(2):  276-281 . 

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The cytotoxicity and DNA damage caused by thioglycolic acid(TGA)-capped cadmium telluride(CdTe) quantum dots(QDs) to hepatocyte line HL-7702 were investigated. Cell viability was measured by 3-(4,5-dimethyl- thiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay; DNA damage was detected by single cell gel electro-phoresis(SCGE); the change of cell cycle progression was examined by propidium iodide(PI)-flow cytometry(FCM); apoptosis was measured by acridine orange/ethidium bromide(AO/EB) assay and Annexin V-FITC/PI-FCM(FITC: fluorescein isothiocyanate). The results show that the cytotoxicity induced by CdTe QDs was increased in a dose-dependent and time-dependent manner; after exposure to QDs for 24 h, as the exposure dose increased, the rate of DNA damage was significantly increased(P<0.05), and the degree of DNA damage was elevated. As the dose of CdTe QDs increased, the percentage of G₀/G₁ phase cells was significantly decreased(P<0.001), while the percent- tages of S and G₂/M phases cells were significantly increased(P<0.001). In AO/EB assay, apoptotic cells could be observed under a fluorescence microscope, and apoptotic rate was increased as exposure dose increased. In Annexin V-FITC/PI-FCM assay, the apoptotic rates of CdTe QDs treated groups were significantly increased compared with that of control group(P<0.05). Our studies indicate that CdTe QDs could influence cell viability, and induce DNA damage, the S and G₂/M phases arrest and apoptosis of HL-7702.



Inclusion Modes of Berberine with β-Cyclodextrin in Aqueous Solution

XIA Dong-hui, REN Xu-dong, JIAO Long, LI Hua

2012, 28(2):  282-286 . 

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The possible inclusion modes of berberine(Berb) with β-cyclodextrin(BCD) in aqueous solution were predicted by molecular docking, molecular dynamics(MD) simulation and binding free energy calculations. Firstly, the molecular docking result reveals that the docking conformations of Berb appeared in two clusters ranked in two opposite orientations. Then, 10 ns MD simulation was performed separately on the lowest energy conformation of each orientation(Mode I and Mode II) obtained by molecular docking. Moreover, based on the trajectories from MD simulation, the binding free energies of the two different modes were calculated by the Molecular Mechanics/Poisson Boltzmann surface area(MM/PBSA) method. Through analyzing the binding free energies of Berb with BCD, we found that Mode II was the preferential inclusion mode, which was in good agreement with the experimental result. In addition, the computed results show that the main impetus for the complex was the van der Waals interaction, but the solvation energy and the entropy change produced an adverse effect on the complex.



Characterization of Gallic Acid Interaction with Human Serum Albumin by Spectral and Molecular Modeling Methods

LIU Zuo-jia, LI Dan, NIU Feng-lan

2012, 28(2):  287-290 . 

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The binding of drugs with human serum albumin(HSA) is a crucial factor influencing the distribution and bioactivity of drugs in the body. To understand the action mechanisms between gallic acid(GA, 3,4,5-trihydroxy- benzoic acid) and HSA, the binding of GA with HSA was investigated by a combined experimental and computational approach. The fluorescence properties of HSA and the binding parameters of GA collectively indicate that the binding is characterized by static quenching mechanism at one high affinity binding site. According to the estimated molecular distance between the donor(HSA) and the acceptor(GA), the binding is related to the fluorescence resonance energy transfer. As indicated by the thermodynamic parameters, hydrophobic interaction plays a major role in the GA-HSA complex. Further, the experimental results reveal that GA is bound in the large hydrophobic cavity of subdomain IIA in the site I of HSA, which is well approved by molecular docking.



Structures and Stabilities of Ni_n(n=31―35) Clusters

SONG Wei, Lü Wen-cai, ZANG Qing-jun, LI Qiu-xia

2012, 28(2):  291-294 . 

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The lowest-energy structures and properties of neutral nickel clusters Ni_n(n=31―35) were studied by a combination method of genetic algorithm(GA) searching with a tight-binding potential and the density functional theory(DFT) calculations. Structural candidates obtained from our GA search were further optimized with first-principles calculations. Four typical isomers of lower-energy neutral Ni_n(n=31―35) clusters were shown, as well as their binding energies per atom(E_b), second differences in energy and magnetic moment. The medium-sized nickel clusters in a size range from 31 atoms to 35 atoms were found to favor the distorted double-icosahedron-like structures. The fragments composed of the central atoms appear as some small stable clusters.



Effect of Zn²⁺ Ions on Upconversion Emission of Er³⁺ in Zn/Er:LiNbO₃ Crystal

QIAN Yan-nan, WANG Rui, XING Li-li, XU Yan-ling, YANG Chun-hui

2012, 28(2):  295-298 . 

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The effect of Zn²⁺ ions codoped on the upconversion emission of Er³⁺ ions in Er:LiNbO₃ crystal under different excitation wavelength was reported. The upconversion emission spectra of Zn/Er:LiNbO₃ following 800 nm excitation reveal an enhanced green emission and a suppressed red emission simultaneously. The cross relaxation processes(²H_11/2+⁴I_13/2→⁴I_11/2+⁴F_9/2 and ⁴F_7/2+⁴I_11/2→⁴F_9/2+⁴F_9/2) are responsible for populating the red ⁴F_9/2 emitting state. The dissociation effect of Zn²⁺ ions on the Er³⁺ cluster sites makes these cross relaxation processes inefficient. Under 980 nm excitation, the Zn²⁺ codoped leads to the decreased intensities of green and red upconversion emissions. These reductions are attributed to the inefficient cross relaxation processes(⁴I_11/2+⁴I_11/2→⁴F_7/2+⁴I_15/2 and ⁴F_7/2+⁴I_11/2→⁴F_9/2+⁴F_9/2) caused by the same dissociation effect of Zn²⁺ ions.



Preparation of Ce(SO₄)₂-doped Phosphosilicate Gels by Mechanical Milling

PENG Hui-fen, HU Lin-na, HE Jun-hua

2012, 28(2):  299-301 . 

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Ce(SO₄)₂-doped phosphosilicate gel was prepared by mechanical milling. Complex impedance analysis proved that the 15 h-ball-milled sample showed a maximum conductivity of 2.97 S/m at 130 °C, which is about 40% higher than that of the sol-gel-prepared sample with the same compositions. NMR results proved that the ball-milled samples contained more Q¹ structural units helpful to an increase in both proton conduction and chemical durability.



Electrochemical Introduction of Active Sites into Super-long Carbon Nanotubes for Enhanced Capacitance

HU Yue, ZHAO Yang, LI Yan, XIE Xue-jun, LI Hui, DAI Li-ming, QU Liang-ti

2012, 28(2):  302-307 . 

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Electrochemical cyclic voltammetric(CV) scan was applied to inducing the partial oxidation and defects of carbon nanotubes(CNTs). The electrochemically induced functional groups and physical defects were demonstra- ted to show positive effects on the nanotube capacitance, as exemplified by super-long CNT arrays as model for the easy fabrication of CNT electrodes. Specifically, the initial hydrophobic nanotube surface becomes hydrophilic and a ten-time enhancement in capacitance is observed with respect to the pristine CNT sample. Thus, the electrochemical CV pretreatment can be used as an effective approach to activate the CNT surface for an enhanced electrochemical performance in capacitors, and many other advanced devices beyond capacitors, such as electrochemical sensors and batteries.



Effects of Electron Donor and Different Solvents on Polarizability and Second Hyperpolarizability of Diradical Complex Involving X(X=B, Al, Ga)

LIU Hai-bo, QIU Yong-qing, YANG Guo-chun, LIU Chun-guang, SUN Shi-ling

2012, 28(2):  308-312 . 

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The polarizability(α) and second hyperpolarizability(γ) were systemically investigated for singlet diradical complex involving X(X=B, Al, Ga) atom. The results show that both the α and γ can be effectively tuned by varying the distance R(between compound A and a water molecule) and acceptor atom X. The lone pair of electrons from the O atom of the water molecule entered into the vacant p orbital of atom X, which increased the diradical character and led to the increase of the α and γ values. Furthermore, the polarizable continuum model(PCM) was used to test the effects of H₂O and CCl₄ solvents on the α and γ values. Both the α and γ values of the studied diradical complex 1a(1b, 1c) in H₂O and CCl₄ were uniformly enhanced. And the solvent effects of H₂O on either α or γ were larger than those of CCl₄.



Synthesis and Properties of Novel Luminescent Compounds Containing Triphenylamine and Bipyridine Units

Lü Hai-jun, LI Xiang-gao, WANG Shi-rong, GAO Wen-zheng, WANG Sha-sha

2012, 28(2):  313-318 . 

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Blue luminescent compounds T1―T4 containing triphenylamine donors, bipyridine acceptors and olefinic linkers were synthesized and characterized by 1H NMR, 13C NMR and high resolution mass spectrometry(HRMS). Four compounds T1―T4 exhibit excellent solubility in common solvents and good film forming properties. Quantum chemical calculations show that compounds T1―T4 have asymmetric linear structures and the proper highest occupied molecular orbital(HOMO) levels. The UV-Vis absorption and fluorescence emission spectra of the four compounds in dilute chloroform solutions and on the solid films were measured. It reveals that compounds T1―T4 exhibit similar spectral behavior, suggesting that these compounds can form amorphous state in solid films. The calculated absorption and emission spectra of compounds T1―T4 are in good agreement with experimentally determined ones. Compounds T1―T4 have absolute fluorescence quantum yield above 17% in dilute chloroform solutions. Four compounds possess high glass-transition temperature(T_g) exceeding 97 °C and the maximum T_g is 155.28 °C for compound T3. Cyclic voltammetry measurements show that these compounds have proper HOMO levels in a range of –5.01― –5.13 eV for hole injection. The properties of compounds T1―T4 indicate that these compounds are candidates for the application in organic light-emitting devices(OLEDs) as hole-transporting materials(HTMs).



Preliminary Studies on X-Ray-sensitive Liposome

MENG Fan-xu, XU Hua-ping, QI Yan-fei, XU Kun, SONG Xiu-ling, NIU Shu, LI Juan

2012, 28(2):  319-322 . 

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The synthesis of a new type of X-ray-sensitive compound “di-(1-hydroxylundecyl) diselenide” and its application in the preparation of a new type of liposome with X-ray sensitivity was reported. This new liposome was synthesized to encapsulate doxorubicin hydrochloride(Dox), with its physical and chemical properties, stability, and radiation sensitivity determined. Based on the pH-gradient method, liposomal Dox was prepared via ultrasonic emulsification and then purified on a Sephadex G50 mini-column. UV spectrophotometry and liquid chromatography were used to detect the encapsulation efficiency and radiation sensitivity of the Dox-loaded liposome. The results show that through changes in release rate, this liposome shows a relative radiosensitivity. In terms of radiation sensitivity, the drug leak rate of the X-ray-sensitive Dox-loaded liposome increased gradually and peaked at 65.4% under the X-ray radiation of a dose of 10 Gy or more than 10 Gy, which is significantly different from that of ordinary liposomes. Meanwhile, X-ray-sensitive Dox-loaded liposome has a good dispersion stability, with an average particle size of approximate 120 nm. The efficiency of this liposome encapsulating Dox was 75.84%, slightly lower than that of ordinary liposomes. The X-ray-sensitive Dox-loaded liposome exhibited suspension stability within 30 d of storage at 4 °C, without visible precipitation. Di-(1-hydroxylundecyl) diselenide is safe and noncytotoxic and compared with those of synthetic phospholipids its synthesis is low cost and does not require complex conditions.



Adsorption/Desorption of Low-density Lipoprotein on a Heparinized Surface of Gold Sensors

LAN Ping, JI Jing, HUANG Xiao-Jun, GUDURU Deepak, GROTH Thomas, VIENKEN Jörg, DING Hui

2012, 28(2):  323-328 . 

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Heparin has been considered to be a potentially useful ligand for low-density lipoprotein(LDL) detection and analysis in a clinical context. In order to construct an affinity surface for preferential adsorption of LDL, heparin-modified gold surface(GS-Hep) was fabricated by a self-assembling method and hydrophobic-modified gold surfaces(GS-Hydro) was used as a control. The morphologies of the modified gold surfaces were investigated by atomic force microscopy(AFM) and the quantity of heparin bound to gold surface was assayed by the toluidine blue(TB) colorimetric method. Water contact angles were determined to investigate wettability on GS-Hep and GS-Hydro. Surface plasmon resonance(SPR) technique was used subsequently to detect the selective binding of LDL with heparin. And the investigation on the effect of pH on LDL adsorption suggests that lower pH lead to higher quantities of LDL adsorption on GS-Hep. Compared with GS-Hydro, GS-Hep is selective for LDL from both single and binary protein solutions. Moreover, adsorbed LDL on GS-Hep could be washed off by injecting elution solution, such as NaCl solution, for the purpose of the regeneration of GS-Hep for further LDL adsorption.



Chain Conformation and Local Rigidity of Soluble Polyimides(II): Isomerized Polyimides in THF

LIU Gui-hua, QIU Xue-peng, BO Shu-qin, JI Xiang-ling

2012, 28(2):  329-333 . 

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Two soluble isomerized polyimides(PIs) synthesized from 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropro- pane dianhydride(6FDA) with either 2,2′-dimethylbenzidine(2,2′-DMB) or 3,3′-DMB were investigated by means of size-exclusion chromatography coupled with multi-angle laser light scattering, a viscometer and a refractive index detector in tetrahydrofuran(THF) with tetrabutylammonium bromide(TBAB) at 35 °C. The corresponding parameters related to conformations α and ν, evaluated from the scaling relationships [η]=K_ηM^α and R_g=K_gM^ν, respectively, were 0.66±0.01 and 0.55±0.02 for poly(6FDA/3,3′-DMB), and 0.67±0.01 and 0.56±0.01 for poly(6FDA/2,2′-DMB), indicating a random coil conformation for both the samples in this mobile system. The persistence length l_p and shift factor M_L(relative molecular weight per unit contour length) were estimated from the relationship between intrinsic viscosity and molecular weight for the wormlike cylinder model proposed by Bohdanecky. Both l_p and M_L showed that the two PIs in THF are flexible chains and exhibit some local rigidity to some extent.



Synthesis and Properties of a Novel Polyimide with Side Chain Containing Biphenyl Unit

WANG Xu, CHANG Tong-xin, ZHANG Peng, CHEN Yi, LIU Xiang-yang

2012, 28(2):  334-339 . 

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A novel biphenyl side-chained diamine with alkyloxy spacer and alkyloxy tail, 4′-butoxy-4-(3,5-diami- nobenzoyloxy)hexyloxybiphenyl(C6BBC4), was synthesized and characterized by FTIR and 1H NMR. A series of polyimide(PI) films with different side chain contents was synthesized from biphenyltetracarboxylicdianhydride (BPDA), 4,4′-oxydianiline(ODA) and C6BBC4, and their thermal properties, optical transparency and liquid crystal alignment property, and so on, were investigated by thermogravimetric analysis(TGA), differential scanning calorimetry(DSC), crystal rotation method, polarizing microscopy and UV-Vis spectra. With the content of side chained diamine increasing from 0 to 100%, the η_inh of poly(amide acid)(PAA) decreased rapidly from 3.0 to 0.51, the glass transition temperature(T_g) of polyimides(PIs) decreased from 274 °C to 203 °C and the Vis-light transmittance of alignment films substantially increased. As for the alignment properties, the pretilt angle of PI alignment films wi- thout rubbing could reach 90° when the content of C6BBC4 was 60% or more. At the same time, the alignment stability could meet the industrial requirements. It was considered that the alkoxy spacer, the biphenyl unit and the alkoxy tail may all play important roles in achieving a large pretilt angle even up to 90°, and the introduction of only the alkoxy spacer or alkoxy tail can also improve the pretilt angle, but not by much.



Modification of Interfacial Interaction of PBT/PP Blends by Adding Main-chain Liquid Crystalline Ionomer with Sulfonic Group

XU Xin-yu, ZHANG Fan, XIE Bing-xi

2012, 28(2):  340-344 . 

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A main-chain liquid crystalline ionomer(MLCI) containing sulfonic group was synthesized by an interfacial condensation reaction. The MLCI was blended with polybutylene terephthalate(PBT) and polypropylene(PP). MLCI interacted with both the dispersed(PP) phase and the matrix(PBT) phase to modify the interfacial interaction of PBT and PP. Differential scanning calorimetry(DSC), scanning electron microscopy(SEM) and FTIR imaging system analysis demonstrated the significance of interfacial interaction in the polymer blends. MLCI brought about good adhesion at the interfacial, which reduced the disperse phase size and enabled a fine PP phase at matrix. The mechanical properties of the ternary blends were improved when a proper amount of MLCI was added. This was attributed to enhanced adhesion at the interface, which invoked better mechanical properties in the blends.



Preparation and Conducting Behavior of Amphibious Organic/Inorganic Hybrid Proton Exchange Membranes Based on Benzyltetrazole

QIAO Li-gen, SHI Wen-fang

2012, 28(2):  345-352 . 

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A series of novel amphibious organic/inorganic hybrid proton exchange membranes with H₃PO₄ doped which could be used under both wet and dry conditions was prepared through a sol-gel process based on acrylated triethoxysilane(A-TES) and benzyltetrazole-modified triethoxysilane(BT-TES). The dual-curing approach including UV-curing and thermal curing was used to obtain the crosslinked membranes. Polyethylene glycol(400) diacrylate(PEGDA) was used as an oligomer to form the polymeric matrix. The molecular structures of precursors were characterized by ¹H, ¹³C and ²⁹Si NMR spectra. The thermogravimetric analysis(TGA) results show that the membranes exhibit acceptable thermal stability for their application at above 200 oC. The differential scanning calorimeter(DSC) determination indicates that the crosslinked membranes with the mass ratios of below 1.6 of BT-TES to A-TES and the same mass of H₃PO₄ doped as that of A-TES possess the –T_gs, and the lowest T_g(–28.9 oC) exists for the membrane with double mass of H₃PO₄ doped as well. The high proton conductivity in a range of 9.4―17.3 mS/cm with the corresponding water uptake of 19.1%―32.8% of the membranes was detected at 90 oC under wet conditions. Meanwhile, the proton conductivity in a dry environment for the membrane with a mass ratio of 2.4 of BT-TES to A-TES and double H₃PO₄ loading increases from 4.89×10^–2 mS/cm at 30 oC to 25.7 mS/cm at 140 oC. The excellent proton transport ability under both hydrous and anhydrous conditions demonstrates a potential application in the polymer electrolyte membrane fuel cells.



Immobilization of Bovine Serum Albumin on Poly(ether ether ketone) for Surface Biocompatibility Improvement

SUN Hui, CHEN Rui-chao, LI Ang, XU Guo-zhi

2012, 28(2):  353-357 . 

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UV-induced graft polymerization of acrylic acid(AA) on poly(ether ether ketone)(PEEK) films was carried out to introduce ―COOH for the subsequent immobilization of bovine serum albumin(BSA). BSA was introduced on PEEK surface based on the condensation reaction between ―NH₂ and ―COOH. The modified surface (PEEK-BSA) was characterized by energy-disperse spectrometry(EDS), X-ray photoelectron spectroscopy(XPS), water contact angle measurement and UV spectrum analysis. The contact angle was found to decrease from 104° for the virgin PEEK films to 63° for the BSA-immobilized PEEK films, demonstrating a significant improvement of surface hydrophilicity. Moreover, the appearance of nitrogen on PEEK film confirmed by XPS and EDS indicates the immobilization of BSA on PEEK surface.



Research Note

Synthesis of Novel Discotic C₆₀-triphenylene Derivative by 1, 3-Dipolar Cycloaddition

YANG Fa-fu, GUO Hong-yu, XIE Jian-wei, LIU Zhi-qiang, XU Bing-ting

2012, 28(2):  358-360. 

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