Table of Content

24 July 2004, Volume 25 Issue 7

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Articles

Hydrothermal Synthesis, Structural Characterization and Fluorescent Property of Coordination Polymer {[Co₂(HBTC)₂(H₂O)₆]·C₄H₁₀N₂·2H₂O}_n

CHEN Jian-Xin, LIU Shi-Xiong

2004, 25(7):  1189-1193. 

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The title complex {[Co₂(HBTC)₂(H₂O)₆]·C₄H₁₀N₂·2H₂O}_n(H₃BTC=1,3,5-benzene-tricarboxylic acid, C₄H₁₀N₂=piperazine) was hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis(MoKα). The crystal structure belongs to triclinic system, space group P1 {with } a=1.054 37(9) nm, {b=1.054 85(9) nm}, {c=0.714 82(5) nm}, {α=102.462 3(28)°}, {β=}{91.350 0(42)°}, γ= 111.018 6(29)°, V=0.720 18(10) nm³, M r=764.37, D_c=1.762 g/cm³, Z=1, {μ=}1.25 mm^-1, F(000)=394. A total of 6 681 reflections were collected, of which 3 247 were unique. The structure was refined to R=0.030 7 and wR=0.081 5 for 2 673 observed reflections with I>2σ(I). The crystal structure consists of cobalt(Ⅱ)carboxylate of BTC, coordination water molecules and discrete piperazine and water molecules. Extension of the coordination geometry around two cobalt atoms(Co1 and Co2) and two HBTC ligands generates an infinite 1D coordination polymer chain. These coordination polymer chains are further interdigitated by two different intermolecular hydrogen bonds( O-H...O and N-H...O) to afford a 3D extended metal-organic networks with a channel dimension of ca. 0.71 nm×0.82 nm. The complex gives a strong fluorescent emission band at 329 nm(λ_ex=312 nm) in the solid state at room temperature.

Synthesis and Fourier Transform Infrared Photoacoustic Spectroscopy of Tetra(p-Stearyloyloxyphenyl)porphyrin Complexes

SHI Yu-Hua, YAHIRO Nobuhide, LIU Wei, SHI Tong-Shun

2004, 25(7):  1194-1198. 

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The Fourier transform infrared photoacoustic spectra(FTIR-PAS) of tetra(p-stearyloxyphenyl)porphyrin TSPPH₂ and its complexes of Mn(Ⅲ), Fe(Ⅲ), Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ) in the range of 3 600-190 cm^-1 were measured and investigated. The bands at 3 318.0 and 968.4 cm^-1 of TSPPH₂ are due to the N-H stretching and in-plane and out-plane bending vibration of the pyrrole groups. All these bands disappear when the complexes are formed. The vibration coupling between the M-N stretching and the porphyrin ring deformation appears at 243 cm^-1. Metal sensitive bands were found at about 1 350, 1 018, 995, 802, 740 and 232 cm^-1.

Syntheses and Crystal Structures of Rare Earth Nitrate Complexes with Phosphinoxide [-CH₂P(O)Ph₂]-substituted Calix[4]arene

ZHAO Ming-Xin, ZHU Wen-Xiang, MA Shu-Lan, YUAN Da-Qiang, WANG Zhe-Ming, WANG Ru-Ji

2004, 25(7):  1199-1203. 

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Two rare earth nitrate complexes with phosphinoxide (-CH₂P(O)Ph₂)-substituted calix arene were prepared and characterized by elemental analysis and IR spectroscopy. Their crystal structures were determined by X-ray diffraction method. Lanthanum nitrate complex [L·La(OH₂)(NO₃)₂]NO₃( L=tetrakis(methylenediphenylphosphinoxide)calixarene) belongs to tetragonal crystal system, space group P4₃2₁2 with a=1.897 7(4) nm, b=1.897 7(4) nm, c=3.108 7(11) nm; Z=4; V=11.196(5) nm³; D_c=1.097 g/cm³, F(000)=3 712, μ=0.491 mm^-1, R₁=0.118 1, wR₂=0.193 0. Europium nitrate complex [L·Eu(OH₂)(NO₃)₂]NO₃·CH₃OH belongs to monoclinic crystal system, space group C₂/c with a=2.881 72(11) nm, b=5.401 5(2) nm, c=2.011 89(7) nm; β=133.406 7(9)°, Z=8; V=22.751 1(14) nm³, F(000)=7 464, R₁=0.067 1, wR₂=0.179 4. The structures of the two complexes are very similar, the rare earth atoms are both nine-coordinated with four oxygen atoms from phosphorus-oxygen bonds and four oxygen atoms from two bidentate nitrate anions and one oxygen atom from a water molecule. The coordination polyhedron is a single-capped square antiprism. In the europium complex, a methanol molecule was included in the calixarene.

Synthesis and Characterization of Novel Bridged Porphyrin Dimers

FU Shi-Tao, WANG Kai, XIE Zheng, LI Zao-Ying

2004, 25(7):  1204-1208. 

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Reaction of 4,4′-dicarboxy-2,2′-bipyridine, 2,6-dibromomethyl pyridine, 2,6-dihydro-xymethyl pyridine and 1,8-diaminonaphthalene with 5-(4-hydroxyphenyl)-10,15,20-triphenyl porphyrin, 5-(4-chloroformacylphenyl)-10,15,20-triphenyl porphyrin and 5-[4-(4′-bromobutoxy)phenyl]-10,15,20-triphenyl porphyrin gave three types bridged diporphyrins 2a-2e, respectively. These intermediates and novel compounds were confirmed by IR, ¹H NMR, MS, UV-Vis and elemental analysis.

Synthesis and Intercalation Behavior of Layered Zirconium (Proline-N-methylphosphonate-phosphate)

RAO Xiao-Ping, FU Xiang-Kai, RAO Kai

2004, 25(7):  1209-1212. 

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Layered zirconium (proline-N-methylphosphonate-phosphate)(α-ZPMPP) was prepared with high crystallization(interlayer distance is 1.52 nm). The intercalation of n-butylamine into α-ZPMPP was also investigated at room temperature. α-ZPMPP and its intercalation complex were characterized by element analysis, IR, XRD and TG-DSC method. It has been found that layered α-ZPMPP possesses different intercalation behavior from α-ZP with the formation of host-guest compound of super-molecule. The interlayer distance of α-ZPMPP-BA was enlarged by 0.45 nm with the intercalation of n-butylamine, the inserted n-butylamine molecules form mono-molecule layer within host matrix and could be removed at 150-250 ℃. The guest molecule n-butylamine forms a mono-molecule layer within host matrix.

FTIR and Raman Spectroscopic Study of Hydrated Ammonium Borates and Their Saturated Aqueous Solutions

WANG Jiang, ZHU Li-Xia, XIA Shu-Ping, WANG Bo, GAO Shi-Yang

2004, 25(7):  1213-1217. 

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FTIR and Raman Spectra of NH₄B₅O₈·4H₂O and (NH₄)₂B₈O₁₃·6H₂O and their saturated aqueous solutions were recorded respectively at 20 ℃. Fundamental vibrational modes were identified and the assignment of vibrational bands were made. Based on the characterization of vibration spectra, the FBB of (NH₄)₂B₈O₁₃·6H₂Owas predicted, as [B₇O₁₁(OH)·B(OH)₃] ^2-, and the strong and sharp band around 516 cm^-1 in Raman spectrum was tentatively assigned to its symmetric pulse vibration, firstly. According to the FTIR differential spectra and Raman spectra, both the main polyborate anions {B(OH)₃, [B ₃O₃(OH)₄] - and [B₅O₆(OH)₄]^-} and their interaction in borate saturated aqueous solution were proposed.

Synthesis, Structure and Dielectric Properties of a New Pervoskite-related Niobate Ba₅LaTi₂Nb₃O₁₈

FANG Liang, ZHANG Hui, MENG Fan-Cheng, HONG Xue-Kun, LIU Han-Xing, YUAN Run-Zhang

2004, 25(7):  1218-1220. 

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A New Niobate Ba₅LaTi₂Nb₃O₁₈ was synthesized by a high temperature solid state reaction in the BaO-La₂O₃-TiO₂-Nb₂O₅ system. The chemical compositions, crystal structure, microstructure, density and melting point of the new compound were characterized by EPMA, XRD, SEM, DTA and so on. Ba₅LaTi₂Nb 3O₁₈ crystallizes the rhombohedral system with unit cell parameters a=0 573 25(2) nm, c=4 213 9(2) nm, and space group R3m, Z=3. The structure may be described as five (Nb,Ti)O₆ octahedra corner-sharing along c axis to form perovskite layer connected by Ba atoms. The Ba₅LaTi₂Nb₃O₁₈ ceramic exhibits a high dielectric constant of 80.5, low dielectric loss of 6.5×10^-4 and small temperature coefficient of dielectric constant of -78×10^-6 K^-1 at 1 MHz due to its close structure and relative high dielectric polarizabilities of Ba²⁺, La³⁺, Ti⁴⁺ and Nb⁵⁺. Ba₅LaTi₂Nb_{3O18 might be a suitable candidate of high εr microwave dielectric ceramics.}

A New Algorithm for Resolving Overlapping Peaks Signal Based on Fractal Theory

CHEN Xiao-Yan, MO Jin-Yuan, ZOU Xiao-Yong, LIANG Li-Fang

2004, 25(7):  1221-1225. 

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A novel overlapping peaks diagram oriented analytical algorithm, named fractal resolving method(FRM), which is based on the fractal theory, is proposed to process analytical signal from instrument. By calculating the fractal dimension of the signal, which can effectively reflect the characteristic of each signal, the information of the peak numbers and peak positions can be accurately obtained. The method will avoid the error generated by man-made estimate and fulfilling the separation of the overlapping peak signals. The experiment results showed that FRM was a powerful tool for processing the peaks signal.

Analysis of Protein-digested Mixture with Dynamic Coating Capillary Electrophoresis-Mass Spectrometry

WANG Xiao-Yan, MOU Xiao-Dun, XU Yun-Min, YANG Peng-Yuan, WANG Hong-Hai 2

2004, 25(7):  1226-1230. 

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An improved method of mass compatible dynamic coating was developed for proteins identification with capillary electrophoresis-mass spectrometry(CE/MS), which kept the high separation efficiency of dynamic coating and eliminated the negative effects of coating reagent to MS detection. The identification efficiency of protein by the peptide mapping of tryptic digested protein was improved. The complex protein mixture was analyzed and successfully identified by this method. The identification efficiency of protein by the peptide mapping to tryptic digested protein was dramatically improved, that the MAscot score of myoglobin digest analysis on CE/MS was increased from³04 to 914 with the dynamic coating. Four protein tryptic digests mixture was also analyzed and successfully identified by this method.

A Hybrid Microfluidic Chip-based Capillary Electrophoresis System with UV Absorbance Detection

CAO Xiao-Dan, FANG Qun, FANG Zhao-Lun

2004, 25(7):  1231-1234. 

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A hybrid microfluidic system produced by coupling a microfabricated glass chip with conventional silica capillary for UV absorbance detection was developed. The system has proved to be robust, and easily fabricated at a low cost. The effects of sample loading and separation field strength on plate number, migration time and signal response were observed in the optimization studies. The reproducibility was examined by using benzoic acid as a model sample and following similar behavior as for complete photolithographically produced glass chip systems. The results showed that the reproducibility is good and the RSD(n=11) was only 1.5% for benzoic acid. The performance of the system was demonstrated by separating sulphamethoxazole(SMZ) and trimethoprim(TMP) in sulphatrim tablets within 70 s. The detection limits were comparable to those obtained with a commercial capillary electrophoresis instrument.

Studies on the Interaction Between Catecholamine Derivatives and DNA by Means of Spectroscopic and Voltammetric Methods

YANG Gong-Jun, XU Jing-Juan, CHEN Hong-Yuan

2004, 25(7):  1235-1239. 

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The interactions between catecholamine derivatives and DNA were investigated by means of cyclic voltammetry, UV-Vis absorption spectra and fluorescence spectra. The results show that the interaction mode is mainly electrostatic interaction at the low concentration of dobutamine and adrenaline whereas intercalative binding plays a dominant role at their high concentration. As for dopamine, it intercalates into the double helix of DNA in the concentration range of 5.00×10^-5 to 9.00×10^-4 mol/L. The binding constants of dopamine, adrenaline and dobuamine with DNA are determined as 1.55×10³, 9.77×10³ and 1.74×10⁴ L/mol, respectively, by electrochemical method.

Effects of Suspended Particulates in Nanhu Lake on Pb and Cd Adsorption to Surface Coatings Developed in the Natural Water

DONG De-Ming, YANG Fan, LI Yu, LIU Liang, ZHENG Na, LIANG Nan

2004, 25(7):  1240-1244. 

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Surface coatings developed in different water obtained by means of stepwise filtration were used to assay the effect of suspended particulates on trace metal adsorption to them. There was a statistically significant correlation relationship between the contents of iron and manganese oxides on surface coatings and those in water, in which surface coatings were developed, even though manganese oxides was influenced obviously by particulates suspended in waters. The classical Langmuir adsorption isotherm was suitable to describe Pb and Cd adsorption to the surface coatings. It was observed that all of the iron oxides on the surface coatings contributed to Pb adsorption while manganese oxides on surface coatings developed in waters containing suspended particulates with a greater diameter contributed most to Cd adsorption. However, the adsorption capacities of Pb and Cd to the surface coatings increased with the decrease of diameter of suspended particulates in water.

Probing Free Radical Damage to Biological Molecules by Spin-labeling Fluorophore

DANG Ya-Min, GUO Xiang-Qun, ZHAO Yi-Bing

2004, 25(7):  1245-1247. 

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A spin-labeling fluorophore(NA-TEMPO^˙), formed by labeling α-naphthalene with a paramagnetic nitroxide(4-hydroxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy), was explored for biologically relevant carbon-centered radicals. The horseradish peroxidase (HPR)/H₂O₂ reaction was used to generate radicals in derivatives of tyrosine and phenylalanine, and the Fenton reaction was used to generate radicals in deoxyguanosine, guanosine, bovine serum albumin(BSA) and DNA. TEMPO ·-NA, a weak fluorescent compound, showed a dramatic increase in fluorescence intensity after scavenging carbon-centered radicals. The spin-labeling fluorophore with dual function groups, the radical recognizing group and fluorescent group, would be significantly useful in monitoring the formation and translocation of carbon-centered radicals in complex biological systems.

Determination of Trace Lead in Unleaded Gasoline by Microwave Digestion-Microwave Plasma Torch Atomic Emission Spectrometry

ZHANG Jin-Sheng, LI Li-Hua, ZHANG Jin-Ping, JIN Qin-Han

2004, 25(7):  1248-1250. 

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Two microwave digestion procedures were developed for unleaded gasoline. Microwave plasma torch atomic emission spectrometry(MPT-AES) was used to determine trace lead in unleaded gasoline after being digested. Optimal conditions (analytical wavelength, microwave power, flow rate of carrier gas for the trace lead determination, flow rate of supporting gas, flow rate of oxygen shielding gas and acid concentrations) were chosen. The effects of concommitant elements on determination of lead were studied. The detection limit for lead was 25 ng/mL, the linear range was 0.05-100 μg/mL. The relative standard deviation for determination of unleaded gasoline samples was less than 4 9%, relative error was less than 3.7%. Standard addition recoveries were all between 93.3%-104.0%. The determination results with microwave digestion were in agreement with those obtained with conventional method. The proposed method is simple, rapid, accurate, and with less possibility to be contaminated by the environment, and of great applied value.

Quality Control of the Powder Pharmaceutical Samples of Metronidazole Based on Near Infrared Reflectance Spectra with Temperature-constrained Cascade Correlation Neural Networks

CUI Xiu-Jun, ZHANG Zhuo-Yong, Peter de B Harrington, REN Yu-Lin

2004, 25(7):  1251-1253. 

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Temperature-constrained cascade correlation networks(TCCCNs) were applied to the identification of the powder pharmaceutical samples of metronidazole based on near infrared(NIR) diffuse reflectance spectra. This work focused on the comparison of performances of the uni-output TCCCN(Uni-TCCCN) to multi-output TCCCN(Multi-TCCCN) by using near infrared diffuse reflectance spectra of metronidazole. The TCCCN models were verified with independent prediction samples by using the "cross-validation" method. The networks were used to discriminate qualified, un-qualified and counterfeit metronidazole pharmaceutical powders. The results showed that multiple outputs network generally worked better than the single output networks. With proper network parameters the pharmaceutical powders can be classified at a rate of 100% in this work. Also, the effects of neural network parameters including number of candidate nodes, type of transfer functions(linear, sigmoid functions and temperature-constrained sigmoid function, respectively) on classification were discussed.

Preparation, Characterization and Chromatographic Performance of p-t-Butyl-calix[8]arene Bonded Silica Stationary Phase

LIU Min, DA Shi-Lu, FENG Yu-Qi, LI Lai-Sheng

2004, 25(7):  1254-1256. 

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p-t-Butyl-calixarene bonded silica stationary phase(CBS) for high performance liquid chromatography was prepared via condensation reaction on the surface of solid .The stationary phase was characterized by means of elemental analysis and FTIR. The chromatographic performance of CBS was studied by using disubstituted benzenes as the solutes and methanol-water or methanol-buffer as the mobile phases, and compared with that obtained on CPS and ODS. The results show that the chromrtographic process can proceed in various retention mechanism, such as π-π, hydrogen-bonding, charge-transfer and inclusion complexation, besides hydrophobic interaction.

Application of Capillary Enzyme Column Enhancd by Using Nanoparticles for Glucose Biosensor Based on Liquid Droplets

FENG Feng, WANG Ke-Min, CHEN Qi-Ting, XIANG Qiu-Fen, CHEN Ze-Zhong, HUANG Hong-Mei, HUANG Shan-Sheng, HUO Xi-Qin

2004, 25(7):  1257-1259. 

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An effective and fast method for assay of micro-amounts of glucose was set up. A new technique for preparation of enzyme columns based on enzyme immobilization by sol-gel was investigated. Glucose oxidase(GOD) and horseradish peroxidase(HRP) mixed with SiO₂ nanoparticles and polyvinyl butyral(PVB) medium were immobilized on the surface of capillary tube, respectively. The experimental results show that nanoparticles can significantly enhance the catalytic activity of immobilized enzyme. Based on GOD column and HRP column, a liquid droplet sensor was developed for the determination of glucose solution. The effect of separated columns and mixed columns on the response of glucose sensor was investigated. The sensor showed a linear response in a range of 2-400 ng/mL with a detection limit of 0.3 ng/mL under the optimum conditions. The characteristics of the sensor including effect of flow-rate, pH and temperature were discussed.

Synthesis, Crystal Structure and Anion Recognition of o-Di(pyrroly-2-formamido)phenylene

YIN Zhen-Ming, YANG Wen-Zhi, HE Jia-Qi, CHENG Jin-Pei

2004, 25(7):  1260-1263. 

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Anions recognition is of interest because anions play many important roles in living organisms. Most currently, it is very desirable to have access to anions recognition in high polar solvents such as DMSO or water. We have designed and synthesized a new dipyrrolylamide compound, o-di-(pyrroly-2-formamido)phenylene(1), which can bind DMSO via hydrogen bonds in solid state. The anions recognition of the compound were studied by the 1H NMR method in a high polar solvent of DMSO. It was evident that compound 1 binds anions via hydrogen bonds of pyrrole NH and amide NH with anions. Compound 1 binds F - more preferably than other anions duo to the well-preorganized structure.

Synthesis, Single Crystal Structure and ¹H NMR Characterization of 3-(2-p-Methylphenylvinyl)-5(4H)-isoxazolone and Theoretical Study for Its Isomerization

HUANG Kun-Lin, LI Cai-Jin, LIU Qun, BAI Hong-Tao, MU Zhong-Cheng

2004, 25(7):  1264-1267. 

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p-Methylphenylvinyl)-5(4H)-isoxazolone was synthesized by the reaction of methylthio ester with NH₂OH·HCl at room temperature and its structure was characterized by single crystal X-ray diffraction. The configuration based on 1H NMR spectrum in CDCl₃ is in agreement with the crystal structure, which indicates that the titled compound is stable in poorly polar solvents, such as diethyl ether and CHCl 3. For 3-(p-methylphenylvinyl)-5(4H)-isoxazolone, the net-charge of C7 is -0.077 and that of C8 is -0.101 by semi-experiential calculations with AM1 and PM3 methods, which are responsible for the chemical shift of H7(6.83) and H8(6.96). With the B3LYP/6-311G^** calculation, the 3-(p-Methylphenylvinyl)-5(4H)-isoxazolone is the most stable configuration among the three isomers.

Research on the Influence of aFGF Antagonist on 3T3 Cell Protein Profiles

LI Xiao-Juan, FU Yu-Qin, GAO Gui, CUI Yin-Qiu, ZHOU Hui

2004, 25(7):  1268-1272. 

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The peptide P₂(VYMSPF) selected from the phage display peptide library is an antagonist of aFGF, but its mechanism of influence on aFGF signal transduction is not clear. We used the two-dimensional electrophoresis and mass spectrometry technique to study the NIH₃T3 cell cultured in the blank IMDM medium and the IMDM mediums containing peptide P₂, aFGF+heparin, aFGF+heparin+peptide P₂ respectively. We selected five protein spots with altered expression in the latter two samples to perform mass spectrometry analysis and database search. Among the identified proteins, expression of three proteins was evidently decreased, including the guanine nucleotide-binding protein, alpha-11 subunit involved in the interior cellular signal transduction and nuclear factor 1C-type involved in the transcription regulation. In summary, these proteins provided the experimental base and clue for further study of the inhibition effect of P₂ on aFGF signal transduction.

Preface

Spectroscopic Evidence of Azone Effect on the Keratin in Mouse Stratum Corneum

ZHOU Xue-Qin, XU Jing, ZHAO Xiao-Dong, ZHANG Zhi-Hui, YAO Kang-De, LIU Dong-Zhi

2004, 25(7):  1273-1276. 

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Chemical enhancers are widely employed to overcome the skin barrier in transdermal drug delivery systems. The penetration mechanism of chemical enhancers is the key point to develop a new transdermal drug delivery system. Azone is a common chemical enhancer and could make the stratum corneum(SC) lipid fluidization. However the protein also contributes to the skin barrier. Transport of large molecules was blocked by the keratin matrix even with an aqueous lipid pathway under a high-voltage pulsing. In this paper the effects of azone on the keratin in the mouse SC were investigated by determination of the molecular mobility and secondary structure of keratin. ¹³C NMR spectroscopy recorded a decreased spin-lattice relaxation time of keratin(t₁) for the carbon in the main and graft chain when treated with azone. ATR-FTIR spectra showed that amide Ⅱ absorption peak of keratin shifted from 1 544.7 to 1 541.4 cm^-1 after the treatment with azone. It was concluded that azone could change the keratin conformation structure partially from α-helix to β-sheet or random coil, leading to a loose keratin structure, therefore reduced the drug transdermal delivery barrier.

Studies on Adsorption Mechanism of TNFα with IgG Ligand

WEI Jiao, FANG Hui, KONG De-Ling, YU Yao-Ting

2004, 25(7):  1277-1281. 

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Tumor necrosis factor α(TNFα) is recognized as the principal inflammatory mediator in the pathogenesis of endotoxemia and dyscracia. Removal of TNFα with immunoadsorbent is one of the focus in the study of anti-TNFα therapy. In the present study, γ-globulin IgG was immobilized onto agarose beads to produce a new type TNFα adsorbent. The affinity mechanism of IgG ligand was studied by means of IgG molecule modification with chemical reagents. The results showed that amino group had a significant influence on the adsorption capacity; carboxyl and indole groups had a negative effect; guanidine and imidazole groups had no effect on adsorption capacity. Furthermore, 1,6-hexamethylene diamine(DAH) was used as a spacer to link agar gel support and IgG ligand which was favourable for reducing the steric hindrance and elevating the adsorption capacity. The IgG immobilized adsorbent showed a strong specificity as well as high efficacy and therefore had a potential for clinical application.

The Ring-enlargement Reaction of Triphenylcyclopentadiene

LI Xin-Cheng, GONG Wei-Tao, NING Gui-Ling, LIN Yuan

2004, 25(7):  1282-1284. 

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A novel silver(Ⅰ) promoted carbon-carbon cleavage reaction of unstrained cyclopentadinene-ring, forming pyrylium cation, was reported previously. In order to explore the formation mechanism of pyrylium ring, in our continuous studies we investigated in detail the role of solvent, silver(Ⅰ) ions, water and molar ratio of silver(Ⅰ) salts to substrate in the reaction, and the effect of reaction temperature on the reaction rate. It was viewed that solvents with a high polarity can accelerate this reaction, and if toluene alone was used as solvent, the reaction could not commence. Silver(Ⅰ) ions in this reaction not only acted as the oxidants, but also as the catalyst considering the structures of substrate and pyrylium product. Trace amount of water existed in the solvents or absorbed on the substrate was crucial to this reaction, and the oxygen atom of the pyrylium ring was from water. Under 1∶2 molar ratio of silver(Ⅰ) to substrate, the reaction proceeded perfectly, whereas higher ratio led to a formation of multi-component products. Higher temperatures than ambient temperature would also complicate the products of reaction.

Articles

Photopromoted Carbonylation of Olefins and Carbon Dioxide Under Ambient Conditions

YIN Jing-Mei, ZHOU Guang-Yun, QI Chun-Qiao, GAO Da-Bin, JIA Ying-Ping, WANG Xiang-Sheng

2004, 25(7):  1285-1287. 

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It was found that photopromoted carbonylation of olefins and CO₂ under ambient conditions could be catalyzed by Co(OAc)₂, Co(acac)₂, CoSalen, Cobalt picolinic ester and[Co(14)-4,11-diene-N₄]I₂[5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dieneatocobalt(Ⅱ)]. The carbonylation of cyclohexene gave some by-products of cyclo-C₆H₁₁-CH₂OH, cyclo-C₆H₁₁-CHO and cyclo-C₆H₁₁-COCH₃, which were established by labelling studies with ¹³CO₂,¹³CH₃OH, CD₃OD and CD₃COCD₃. CH₃(CH₂)₇-CH₂OH, CH₃(CH₂)₇-CHO and CH₃(CH₂)₇-COCH₃ were also confirmed as the by-products of carbonylation of 1-octene.

Isolation, Purification and Structural Elucidation of EPS-Ⅰ,an Extracellular Polysaccharide from Enterococcus durans

GU Xiao-Mei, WU Hou-Ming, MA Gui-Rong

2004, 25(7):  1288-1290. 

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The rough crystal of exopolysaccharide produced by Enterococcus durans, a strain of lactic acid bacteria screened from the intestine of a cock in our laboratory, was purified by CM-cellulose column chromatography, DEAE-Sephadex A-25 ionexchange and Sephadex G-100 gel chromatography to give EPS-Ⅰ. The EPS-Ⅰ was eluted as a single peak in HPLC analysis, indicating the homogeneity of EPS-Ⅰ and free from low-molecular-weight polysaccharides. The molecular weight of the EPS-Ⅰ was determined as 42 000 by the light scattering method. The result of its elemental analysis was C 41.08% and H 7.23% without the elements of N, P and S. Monosaccharide analysis showed that it was composed of Glc and Man in a molar ratio of 4∶1. Sugar composition analysis, methylation analysis and ¹H and ¹³C NMR spectroscopy revealed that the EPS-Ⅰ was composed of pentasaccharide repeating units. The sequence of sugar residues was determined by using two-dimensional NMR, including heteronuclear multiple-bond correlation(HMBC) and nuclear overhauser effect spectroscopy(NOESY). The structure of the pentasaccharide repeating unit of EPS-Ⅰ was given, a new excellular polysaccharide from lactic acid bacterium compared with other EPSs was reported.

A Method for Constructing the Reasonable and Most Contracted Localized Orbitals with Less Computational Efforts

FENG Hua-Sheng, BIAN Jiang, LI Le-Min

2004, 25(7):  1291-1297. 

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A method is proposed to construct the reasonable and most contracted localized orbitals with less computational efforts. The non-orthogonalized localized orbitals(NOLMOs) do not possess "orthogonalization tails", thus they are more localized and contracted, and more transferable comparing to the corresponding orthogonalized localized orbitals(OLMOs). Therefore, they are more suitable for use in theoretical study of chemical problems. However, if the orthogonalization requirement is simply removed without imposing other constraints when one intends to construct the most contracted NOLMOs by variation, unreasonable results may be obtained: the NOLMOs tend to linear dependence or they are ill-conditioned linear independence. In this paper, it is proposed that constraining the centriods of NOLMOs at those of the corresponding projected natural bond orbitals(PNBO) can be used to replace the orthogonalization requirement for constructing the reasonable NOLMOs contracted as far as possible(the reasonable most contracted localized orbitals). The calculated results for a series of different kinds of molecules show that, by means of the proposed method, the obtained NOLMOs are linearly independent and reasonably distribute in space, and their spreads are very close to the best results presented in literatures, while the computational efforts decrease considerably. The proposed method can be used to construct the reasonable and most contracted NOLMOs in very large systems due to the fact that the computational efforts for constructing PNBOs only linearly increase with the increase of atoms in systems.

High Pressure Vapour-liquid Equilibrium of Supercritical Carbon Dioxide+Diethyl Carbonate System

ZHAO Xue-Feng, CHEN Li, TIAN Yi-Ling, ZHANG Feng-Cai, XUE Yuan

2004, 25(7):  1298-1302. 

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Vapor-liquid equilibrium data of the supercritical carbon dioxide+diethyl carbonate system were measured isothermally at 333, 353, 373 and 393 K in the pressure range of 3-15 MPa. The measurements were carried out in a cylindrical autoclave with a movable piston and an observed window. It is shown that the solubilities of supercritical CO₂ in DEC increase drastically with the increase of pressure at the given temperature, but the content of DEC in gas phase increase faintly. The critical values p_c,T_c,x_c and V_c of the binary system were predicted.

Magnetic Property and Relaxation Kinetics of Light-induced Valence Tautomerism of Co Complex with a Low Valence

CUI Ai-Li, SATO Osamu

2004, 25(7):  1303-1305. 

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A new compound Co[HN(C₅H₄N)₂](3,5-DBSQ)₂ with LIESST(Light-induced excited spin state trapping) and LIVT(Light-induced Valence Tautomeric) was synthesized. The magnetic property and relaxation kinetics of valence tautomerism were investigated. The starting temperature of valence tautomerism is about 300 K. After illumination with 532 nm light at 5 K, Co(Ⅱ)(low spin) obtained an electron from ligand 3,5-DBCAT and became Co(Ⅲ)(high spin) while 3,5-DBCAT changed to 3,5-DBSQ. The LIVT increased the effective magnetic moment of the complex. At the temperatures ranging from 5-30 K, the k VT values are independent of temperature, which means that the tunneling is the predominant mechanism for the relaxation behavior. At the temperatures from 30-70 K, the activation energy of relaxation after illumination is 252 cm^-1. When the complex is heated after illumination, the magnetization returns to the original state before irradiation. This means the relaxation temperature, T_R, is 70 K.

Preparation of ZrO₂∶Er³⁺, Yb³⁺ Nanocrystals and Split of Er³⁺ Energy Level in Crystalline Field

JIA Ruo-Kun, LIU Yan-Mei, HE Dong-Liang, LÜ Qiang, SHAN Gui-Ye, LIU Zhao-Yue, BAI Yu-Bai, LI Tie-Jin

2004, 25(7):  1306-1309. 

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The ZrO₂∶Er³⁺, Yb³⁺ nanocrystals were prepared by low temperature crystallizing in 1,3-butadinol. Red upconversion emission at 660 nm was observed from ZrO₂∶Er³⁺, Yb³⁺ nanocrystals with 980 nm excitation. The X-ray diffraction patterns confirm that the nanocrystals are cubic. The mechanism of nanocrystals upconvertion was studied. The Stark splits of the two excited states of Er³⁺ were calculated based on the theory of crystallization. The results confirm that the upconverted mechanisms in the ZrO₂∶Er³⁺, Yb³⁺ nanocrystals are due to the two processes, one is a consecutive absorption of two 980 nm photons process, and the other process is that electrons transfer to substeady states after absorption of 980 nm photons, then absorb 980 nm photons.

Effect of Surface State of Al Sheet on Photocatalytic Behavior and Photoinduced Hydrophilicity of TiO₂ Film

DAI Wen-Xin, WANG Xu-Xu, SHAO Yu, FU Xian-Zhi, LIU Ping

2004, 25(7):  1310-1313. 

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TiO₂ films on the surface of Al₂O₃/Al and pure Al sheet were prepared by a dip-coating technique of TiO₂ colloid. The photocatalytic degradation of oleic acid and photocatalytic oxidation of C₂H₄ on the samples were studied by FTIR ATR technique and a batch reactor, respectively, and the photoinduced hydrophilic property of the samples was evaluated by water contact-angle. Compared to TiO₂/Al, TiO₂/Al 2O₃/Al showed a higher activity of photocatalytic degradation for oleic acid, but lower activity of photocatalytic oxidation of C₂H 4 and poorer photoinduced hydrophilic property. The diversity could be explained with the help of difference of the reaction mechanism and the transfer of electron between Al and TiO₂. The result suggests that photocatalysis and photoinduced hydrophilicity of TiO₂ film are dependent and independent on each other.

X-ray Reflectivity Studies on Metal Nanoparticle/Polyelectrolyte Multilayers

LI Xiu-Hong, TAN Zhi-Min, HUANG Lan, LI Xiao-Long, MAI Zhen-Hong, LI Ming

2004, 25(7):  1314-1317. 

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Electrostatic self-assembly technique was used to prepare Au-nanoparticle/polyelectrolyte multilayers. The microstructures of the films were characterized by X-ray reflectivity and the atomic force microscopy. It is found that when the polyelectrolyte layers under the Au nanoparticles were thin, there were no clear interfaces in the films; when the polyelectrolyte layers got thick, the interfaces become clear. Therefore, it needs to increase properly the thickness of the polyelectrolyte layers in order to get the metal nanoparticle/polyelectrolyte multilayers with clear interfaces.

Growth Mechanism of Magnetic γ′-Fe₄N Thin Films Deposited by D.C. Magnetron Sputtering

XU Wei, WANG Xin, FENG Shou-Hua, ZHENG Wei-Tao, TIAN Hong-Wei, YU Shan-Sheng, YANG Kai-Yu

2004, 25(7):  1318-1321. 

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A variety of natural and industrial dynamical processes, such as vapor deposition, spray painting, and chemical dissolution, lead to the formation of rough surfaces. In the light of dynamical scaling, the growth and formation of such rough interfaces can be researched. In this paper, we deposited Fe-N thin films on glass substrates at different temperatures and different time by DC magnetron sputtering in N 2/Ar atmosphere. The composition, structure and saturation magnetization of the films were investigated. The growth of the γ′-Fe₄N phase was also analyzed by using dynamic scaling. It is found that the surfaces of the Fe-N films typically exhibits self-affine structures both in space and time, and the 2-dependent nontrivial exponents are α≈0.57±0.20 and β≈0.61±0.02, respectively. The scaling relationship α+α/β≈2 is obeyed, which is in agreement with KPZ universality. The growth process allowed the formation of overhangs or voids, and desorption was the dominant relaxation process.

Fabrication of Ordered Honeycomb Structure Porous Film with Doped Polyaniline and Its Formation Mechanism

YU Chun-Ling, ZHAI Jin, GAO Xue-Feng, WAN Mei-Xiang, JIANG Lei, LI Ze-Sheng, LI Tie-Jin

2004, 25(7):  1322-1324. 

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Double-layer honeycomb structure of 4-dodecylbenzenesulfonic acid(DBSA)-doped polyaniline(PANI) is fabricated in the humidity atmosphere by self-assembly method. The driving force of this procedure is capillary force(self-assembly) and the water droplet plays the role as template.The morphology and electric property are studied by atomic force microscope and this honeycomb structure is proved to be electro-active. Additionally, the double layer′s formation mechanism is proposed in the systems while the density of organic solvents is higher than that of water.

Synthesis of Propylene Carbonate Catalyzed by Dawson-type Polyoxometalate

WANG Chun-Gang, JIANG Chun-Jie, HU Chang-Wen

2004, 25(7):  1325-1327. 

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In the presence of Dawson-type polyoxotungstate, α 2-[(n-C₄H₉)₄]_(11-n)P₂W₁₇O ₆₁(M_n+·Br)[abbreviated as P₂W₁₇M·Br, M=Co(Ⅱ), Mn(Ⅲ), Cu(Ⅱ)] and saturated [(C₄H₉)₄N]₆P₂W₁₈O₆₂(abbreviated as P₂W₁₈), cycloaddition reaction of carbon dioxide to propylene oxide were studied under moderate reaction conditions without any additional organic solvents. The experimental results indicated that the synthesis of propylene carbonate was completed in 98% yield and 100% selectivity by using {P₂W₁₇Co·Br} as the catalyst, while the P₂W₁₈ complex showed the lowest catalytic activity with less than 1% yield of propylene carbonate. The dependency of the catalytic activity on transition metal of mono-substituted polyoxometalate, P₂W₁₇M·Br, as well as the nucleophilicity of the bromide ion was concluded from the process analysis.

Preparation of Monodisperse PS Microspheres by Using Membrane Emulsification-drying Method in Liquid

BAO De-Cai, ZHANG Qiong-Gang, LIU Xiu-Dong, MA Xiao-Jun, YUAN Quan

2004, 25(7):  1328-1330. 

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The membrane emulsification method was adopted to prepare monodisperse polystyrene(PS) microspheres. Stable uniform-sized emulsion droplets were successfully obtained by pressing PS solution through the Shirasu Porous Glass(SPG) membrane into water solution containing emulsifiers at appropriate applied pressures. Monodisperse PS microspheres with size in the range of 2-20 μm were prepared by drying in liquid. The size of PS microspheres was strongly dependent on the pore size of SPG membrane and the concentration of PS solution. The size of the PS microspheres increased with the increase in the pore size of SPG membrane and the concentration of PS.

Thermodynamics Properties of Axial Coordination Reaction of Fluorouracilum and Iron Porphyrin

YAN Xi, ZHENG Ze-Bao, WU Fu-Li, LU Li-Lin, ZHU Wen-Xiang, ZHANG Shou-Fang

2004, 25(7):  1331-1333. 

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To discover the mechanism of side-effect brought on fluorouracilum for human, FeTPP was prepared for simulating the character of haemachrome. Equilibrium constants β, Δ_rH^0-_m and Δ_rS^0-_m in the axial coordination reaction between FeTPP and fluorouracilum were evaluated by means of spectral absorption. The structure of the complex was optimized by MM⁺ molecular mechanics method. We found that fluorouracilum can react with FeTPP and form octahedron complex with two axial ligands. The viewpoint that fluorouracilum can damage biological function of metal porphyrin and bring about the medication sickness for human was proposed.

Rheological Properties of Quaternary Ammonium Gemini Surfactants in Aqueous Solutions

XU Xiao-Ming, LIN Yong-Sheng, WU Zhang-Feng, HAN Guo-Bin

2004, 25(7):  1334-1337. 

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By means of oscillatory shear flow in the capillary, rheological experiments of aqueous solutions of quaternary ammonium Gemini surfactants containing methylene groups spacer(CH₂) s(referred to C_12-s-C₁₂·2Br, s=2,4,8) were carried out. By using dynamic light scattering method, the mean hydrodynamic radius(R h) of C_12-s-C₁₂·2Br micelles were measured to investigate the growth of C_12-s-C₁₂·2Br micelles. The aim of the experiments is to explore the effect of spacer chain length on the size and shape of micelles and the rheological property of the solution. The results show that the rheological property is mostly determined by the size and shape of micelles which depend on the spacer chain length of C_12-s-C₁₂·2Br. The rheological property of spherical and rodlike micelles solution is purely viscous, whereas the solution of threadlike micelles is viscoelastic. The viscosity of the solutions increases with the increase of NaBr concentration or the decrease of temperature.

Percolation Network and Piezoresistive Behavior of HDPE Conducting Composites Filled With SCF

ZHOU Jian-Feng, SONG Yi-Hu, ZHENG Qiang, WU Gang, SHEN Lie

2004, 25(7):  1338-1341. 

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Piezoresistive behavior(PRB) of high-density polyethylene(HDPE)-matrix conducting composite filled with short carbon fiber(SCF) was studied in relation to the structure alternation of the percolation network. Scan electron microscopy(SEM) micrographs revealed that the electrical conductivity of HDPE/SCF composites dominantly depended on the percolation network formed by the SCF physical contact. PRB was attributed to the changes of tunneling current and the destroying-rebuilding competition of the conducting long-carbon-chain as well as the percolation network. The resistance at zero stress after unloading decreased continuously with the increase of the number of compressive cyclic tests, which could be related to the residual compressive strain induced by the crystalline slippage and the intermolecular friction of the polymer matrix in the amorphous region. The stability of PRB could be improved significantly by a certain number of compressive cycles, and the improvement became more prominent as the volume fraction of SCF approached the percolation threshold.

Chemical Method of Breaking the Cell-loaded Sodium Alginate/Chitosan Microcapsules

XUE Wei-Ming, YU Wei-Ting, LIU Xiu-Dong, HE Xin, WANG Wei, MA Xiao-Jun

2004, 25(7):  1342-1346. 

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A novel chemical method to break and dissolve cell-loaded microcapsules under physiological condition was established, especially aiming at alginate/chitosan/alginate(ACA) microcapsules. The microcapsule-broken process was designed to proceed under an approximately physiological condition for the consideration of maintaining the cytoactive. The microbial cell(Pichia pastoris GS115) and animal cell(L929) were chosen as the model cells, and the microcapsule-broken solution(MBS) was basically composed of NaHCO₃ and Na₃C₆H5O₇·2H₂O. The effects of MBS on the breaking of microcapsules and on the cytoactive were thoroughly investigated. Moreover, the mechanism of the breaking of microcapsules was analyzed. It was demonstrated that the microcapsules could be broken within 30 s, the breaking ratio of the microcapsule was 100%, and the fragments of the microcapsules was dissolved completely. It was also determined that the survival rate of cells was above 85%. Thus, the novel method will make it possible to quantitatively analyze the growth of cells in microcapsules, to examine the morphology and function of cells, to recover the cells and to purify metabolic products, which is always difficult to realize at present. Therefore, the chemical method of breaking and dissolving cell-loaded microcapsules would be the important component of microencapsulation technology applied to the cell culture and cell transplantation.

LBL Self-assembly of Chondroitin Sulfate and Collagen onto Poly(L-lactic acid) Surface for Improving Its Cytocompatibility with Endothelial Cells

ZHU Ya-Bin, GAO Chang-You, LIU Yun-Xiao, GONG Yi-Hong, SHEN Jia-Cong

2004, 25(7):  1347-1350. 

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Amino groups were covalently introduced onto poly(L-lactic acid)(PLLA) surface by the aminolyzing reaction between 1,6-hexanediamine and the ester groups of PLLA. The amino groups provides the possibility to modify PLLA surface using technology of layer-by-layer (LBL) self-assembly, because these aminolyzed polyesters can be used as the polycationic substrate. Biocompatible chondroitin sulfate A (CS) and collagen type Ⅰ were chosen to be deposited alternately onto the aminolyzed PLLA membrane surface. The deposition process was monitored by UV-Vis absorbance spectroscopy and energy transfer by fluorescence spectroscopy after the polyelectrolytes were labeled by fluorescein isothiocyanate (FITC) and rhodamine isothiocyanate, respectively. The layer thickness increased linearly at first with the increase of the deposited layers, and then increased slowly due to the layer interpenetration. The existed collagen improved the cytocompatibility of PLLA to human endothelial cells. The cell attachment, activity and proliferation increased greatly on the PLLA membranes assembled with only one bilayers of CS/collagen (with collagen as the outermost layer). Cells also showed morphology of flat endothelium, and a confluent cell layer was reached after being cultured for 4 d. Due to the advantages of those traditional methods, LBL self-assembly technique will attract many attentions in scaffold modification in tissue engineering.

Studies on the Blend Composed of HDPE, PA6 and PVAc-Montmorillonite Nanocomposite Prepared via γ-ray Irradiation

DING Yun-Sheng, ZHANG Zhi-Cheng

2004, 25(7):  1351-1354. 

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The in suit intercalated polymerization of vinyl acetate(VAc)-montmorillonite(MMT) was initiated via γ-ray irradiation and PVAc-MMT composite was obtained. PVAc was also prepared by the same way. X-ray diffraction(XRD) results show that the PVAc-MMT composite is a kind of nanocomposite, and transmission electron microscopy(TEM) observation gives the same result directly. Ternary blend composed of PVAc-MMT/HDPE/PA6(PMHP) was prepared by melt-mixing way, and scanning electron microscopy(SEM) testing result reveals that the PVAc-MMT nanocomposite dispersed in the PMHP for a kind of capsule particles. Thermogravimetric analysis(TGA) results show that the thermal stability of PMHP is much greater than that of PVAc/HDPE/PA6(PHP) blend because of the phase structure change of PMHP and the existence of PVAc-MMT nanocomposite in that of the ternary blend of PMHP, for the same reason the mechanical properties of PMHP is better than HDPE and PHP blend.

Mechanical and Thermal Behaviour of CaCO₃/PEEK Comopsites

ZHOU Bing, YU Chuang, YANG Yan-Hua, JI Xiang-Bo, JIANG Zhen-Hua

2004, 25(7):  1355-1358. 

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Poly ether ether ketone(PEEK)-CaCO₃ composites were prepared on a twin screw extruder with different mass ratios of CaCO₃ to PEEK from 0 to 25%. The influence of surface treatment of the particles(with or without SPEEK) on the mechanical and thermal properties of the composites was studied. The experiments included tensile tests, flexural tests, notched Izod impact tests, differential scanning calorimetry(DSC), and scanning electron microscopy. The modulus and tensile strength of the composites increased at the same filler content compared with the system in which CaCO₃ particles were not treated, and with a content up to 10% the tensile strength was higher than that of the neat PEEK. This increase was connected to the bonding between the particles and the PEEK matrix, as can be proved by the SEM picture of the cryogenic fracture surface of the composites. The impact resistance showed large improvement with the increase of particle content up to 15%. This was mainly due to the improved dispersion of the filler particles and the strong interaction between and the fillers and the matrix. DSC experiments showed that the glass transition temperature(T_g) and melting temperature(T_m) were influenced by the content and surface properties of the filler particles. The T_g increased with increasing the content of fillers while T_m decreased. Further, the melting enthalpy of the composites was found to decrease with increasing CaCO₃ loadings, but the melting enthalpy and crystalline degree of the PEEK matrix was not sensitive to the content and the surface properties of the CaCO₃ particles. In this study the fillers treated with SPEEK were found to give better combination properties, which indicated that SPEEK was a good coupling agent in the CaCO₃/PEEK composites.

Synthesis of Amino-centered, Nitro-capped Phenylacetylene-monodendrons

CHEN Meng-Lin, CHI Chun-Yan, WANG Xian-Hong, ZHAO Xiao-Jiang, LI Ji, WANG Fo-Song

2004, 25(7):  1359-1362. 

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A rapid and convenient solid-supported iterative divergent/convergent approach was utilized to prepare the nitro-capped phenylacetylene-monodendrons I-G1-(NO₂)₂ and I-G2-(NO₂)₄, which were transformed into the expected amino-centered, nitro-capped monodendrons NH₂-G1-(NO₂)₂ and NH₂-G2-(NO₂)₄ by Heck-Cassar-Sonogashira-Hagihara coupling reactions. Transmittance FTIR spectroscopy followed the whole solid-phase approach. The absorption peaks at 2 157(1) and 3 311(1) cm^-1 were the characteristic of the stretching vibration for the carbon-carbon triple bond in trimethylsilyl-protected acetylene and the carbon-hydrogen bond in the terminal acetylene after desilylation, respectively. Upon coupling reaction, the peak at 1 343(1) cm^-1 was observed in P-G1-(NO₂)₂ and P-G2-(NO₂)₄, which was the characteristic of the stretching vibration for the terminal nitro groups. Both NH₂-G1-(NO₂)₂ and NH₂-G2-(NO₂)₄ were confirmed by UV-Vis, IR, NMR, EI-MS and ESI-MS techniques. UV-Vis spectra of the obtained monodendrons showed a good relationship with their structures. Both I-G2-(NO₂)₄ and NH₂-G2-(NO₂)₄ showed a blue shift of (20±1) nm for the absorption peaks, compared with those of I-G1-(NO₂)₂ and NH₂-G1-(NO₂)₂, which is probably due to the increase in the number of the terminal nitro groups. Upon coupling with the electron donor-amino group, both NH₂-G1-(NO₂)₂ and NH₂-G2-(NO₂)₄ showed a red shift of (6±1) nm for the absorption peaks, compared with those of I-G1-(NO₂)₂ and I-G2-(NO₂)₄.

Biomimetic Octacalcium Phosphate Coating with Biological Activity Deposited on the CVI C/C Surface

XIONG Xin-Bo, LI He-Jun, HUANG Jian-Feng, MA Wei, LU Jin-Hua, HUANG Min

2004, 25(7):  1363-1367. 

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In order to make biomimetic calcium phosphate on the surface of bionert CVI C/C composite, a novel method was put forward with which CVI C/C composite is treated by cathode sonoelectrochemical technology, then the as-treated CVI C/C is immersed in a supersaturated calcium phosphate solution(SCPS) to induce the growth of calcium phosphate. XPS, XRD, SEM and FTIR analysis results show that octacalcium phosphate [Ca₈ (HPO₄)₂(PO₄)₄·5H₂O] coatings can grow on the surface of CVI C/C, while no calcium phosphate will be gotten on CVI C/C. The deposition and formation mechanism of OCP coatings was also discussed.

Photoresponse Behaviour of a New Photochromic Liquid Crystalline Carbosilane Dendrimer of the First Generation Containing Hexyloxyazobenzene Moieties Groups in Its Periphery

ZHANG Qi-Zhen, LIU Jian-Qiang, YIN Xiao-Ying, ZHANG Jing-Zhi

2004, 25(7):  1368-1372. 

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Studies were made of on the absorbance at 360 nm A₃₆₀, difference of absorbance at 360 nm ΔA₃₆₀, intensity of light I₀, absorption intensity of light I_a, molar extinction coefficient at 360 nm €₃₆₀, maximum absorption wavelength λ_max, quantum yield Φ, activation energy E, trans/cis isomer absorbance ratio A/A₀, trans/cis photo-isomerization reaction rate constant k_p, photo back-isomerization positive/counter reaction rate constants k_t and k_c, thermal back-isomerization reaction rate constant k_H at different temperatures and photo back-isomerization reaction equilibrium value k_t/k_c of a new carbosilane photochromic liquid crystalline(LC) dendrimer of the first generation(G1) containing twelve 4-hexyloxyazobenzene moieties in its periphery and azobenzene unit M3 in solvents such as chloroform, tetrahydrofuran and so on. solvent were described. The photochromic rate constant of G1 and M3 are 10^-1 s^-1, their photoresponsive rate are 10⁷ times larger than that of photochromic liquid crystalline polysiloxane.

Effect of Degree of Branching on Glass Transition Temperature for Hyperbranched Polyether

MAI Yi-Yong, ZHOU Yong-Feng, YAN De-Yue

2004, 25(7):  1373-1374. 

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The effect of the degree of branching(DB) on glass transition temperature(T_g) for a hyperbranced poly[3-ethyl-3-(hydroxymethyl)oxetane](PEHO) was measured by DSC. The results show that the T_g of PEHO decreases with the increasing DB. It is presumed that the smaller the DB of the PEHO sample, the smaller the free volume of the material, and the stronger the intermolecular interaction, which means more energy is needed to make the PEHO chains move, finally it leads to the increase of T_g.

Super-hydrophobicity of Aligned Polymer Nanopole Films

JIN Mei-Hua, FENG Lin, FENG Xin-Jian, ZHAI Jin, JIANG Lei, BAI Yu-Bai, LI Tie-Jin

2004, 25(7):  1375-1377. 

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Wettability is a very important property governed by both the chemical composition and the geometrical structure of solid surfaces. Super-hydrophobic surface[with water contact angle(CA) larger than 150°] have been extensively investigated due to their importance for industrial applications. In the present study, we describe a rather simple method for synthesizing separated alignments of polymer nanopole films, which has super-hydrophobic property with water a contact angle as high as 152.0°. Nanostructures that induce the large fraction of air on the surface cause this unique property.

Nonisothermal Crystallization Kinetics of PEEK-PEDEK Block Copolymer

WANG Han-Fu, ZHAO Xiao-Gang, LIU Xin-Cai, CHEN Liang, WANG Li-Feng, CHEN Chun-Hai , WU Zhong-Wen

2004, 25(7):  1378-1380. 

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The nonisothermal crystallization kinetics of PEEK-PEDEK block copolymers was studied and the results showed that the Avrami exponent n of each sample was generally larger than 3, which indicates the initial crystallization of the complex. The crystallization behavior could be described as heterogeneous, multi-dimensional spherical growth with thermal nucleation. The activation energy was calculated and was explained with the constitution changes of the molecular chains that caused by the introduction of biphenyl moiety.

Sodium Alginate-chitosan Microcapsules Using as Bio-microreactor in Intestinal Tract

YU Wei-Ting, XIONG Ying, LIU Xiu-Dong, WANG Wei, XIE Wei-Yang, MA Xiao-Jun

2004, 25(7):  1381-1383. 

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An intestinal bio-microreactor with potential application prospect as a drug delivery system was proposed and studied. It was designed to overcome the problems such as complexity of separation and purification, and subsequent high costs, which always exist in producing genetically engineered drugs. For example, the process of separation and purification can be omitted by oral administration of genetically engineered microbes entrapped in semi-permeable membrane of microcapsules. The microencapsulated cells can live, metabolize and secrete therapeutic proteins in intestinal tract. In this paper, Pichia pastoris GS115 was selected as the model microbe, alginate-chitosan (AC) microcapsules as the carrier, and the physicochemical performance of the intestinal bio-microreactor was studied. It was found that the encapsulation efficiency of living yeast cells during the preparation of microcapsules was about 80%. It was shown that all AC microcapsules with yeast cells were kept intact in simulated gastric solution and simulated intestinal solution, and the survival of microencapsulated cells in simulated gastrointestinal solutions was 200-times higher than that of free cells, which showed that AC microcapsules can protect the activity of yeast cells. Furthermore, when being orally administered in mice, AC microcapsules could go through stomach and adhere to the surface of small intestinal mucous membrane over 12 h. Therefore, it was concluded that AC microencapsulated yeast cells could be used as intestinal bio-microreactor to secret bio-drugs in vivo directly.

Segment Motion and Miscibility of STVPh/PPC Blend System

QIU Fu-Rong, CHEN Shi-Ming, TAN Li, PING Zheng-Hua

2004, 25(7):  1384-1386. 

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The polymer-polymer interaction parameters of STVPh/PPC blends were calculated by Hildebrand solubility parameter. Accordingly the miscibility of the blends was predicted. The segment motion and miscibility of blends were also investigated by electron spin resonance(ESR) spin probe method. ESR spectra were measured as a function of temperature and the hydroxyl content in STVPh. For all blends, two spectral components with different rates of motion, a "fast" and a "slow" component were observed. This result showed that the nitrooxide radical existed in two different matrixes, a more flexible PPC-rich and a more rigid STVPh-rich micro domain. In addition, T 5mT and rotational correlation time τ c and activation energy E a were obtained from ESR spectra, which indicated the hydrogen bonding between the carbonyl and ether oxygen in PPC and the hydroxyl in STVPh was enhanced with increasing the hydroxyl content in STVPh.