Table of Content

10 July 2005, Volume 26 Issue 7

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Articles

Hydrothermal Synthesis of a Three-dimensional Open-framework Oxyfluorinated Titanium Phosphate and ComputerSimulation of the Template Positions

CHEN Chao, DING Hong, LI Guang-Hua, BI Ming-Hui, YI Zhuo, LI Yi, LI Shou-Gui, MENG He, LIU Li, PANG Wen-Qin

2005, 26(7):  1189-1193. 

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Ti₄(PO₄)₄(HPO₄)₂F₂·[(CH₃)₂N(CH₂)₂NH₃][H₃O](denoted TP-J3), a oxyfluorinated titanium phosphate compound, with a three-dimensional open framework was hydrothermally synthesized. It was characterized by X-ray powder diffraction, inductively coupled plasma, elemental analysis(CHN), and thermogravimetric analysis. The structure was determined by single-crystal X-ray diffraction analysis, which crystallizes in the trigonal space group P1 with a=0.635 3(1) nm, b=0.869 9 (2) nm, c=1.106 9(2) nm, α=93.94(3), β=90.13(3), γ=107.96(3), V=0.580 4(2) nm³, Z=2, R₁0.039 1, wR₂0.095 9, GOF=1.052. The structure was constructed from the secondary building units(SBUs, [Ti₂(PO₄)₂(HPO₄)F]. There exist two types of eight-membered ring channels along the b and c axes, which forms a 'cage-like structure'. The computer simulation was used to determine the possible positions of the organic template within the cages.

Synthesis, Crystal Structure and Oxidation Activity of Lipoxygenase Model Compound [Fe(CTB)Cl]Cl·3CH₃CH₂OH·H₂O

ZHAO Xian-Zhen, MENG Xiang-Gao, LIAO Zhan-Ru

2005, 26(7):  1194-1197. 

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A novel lipoxygenase model compound, Cl·3CH₃CH₂OH·H₂O was synthesized and characterized(CTBN,N,N',N'-tetrakis(2'-benzimidazolylmethyl)-ortho-diamine trans-cyclohexane). The single crystal X-ray analysis shows that this compound crystallizes in the monoclinic system, space group P2₁/n with cell parameters a=1.129 38(7) nm, b=1.490 04(9) nm, c=2.693 46(17) nm, β=9.195 30(10)°, V=4.530 0(5) nm³, and Z=4; R=0.060 2, wR=0.162 9. It is interesting that the iron(Ⅱ) ion is bonded to three benzimidazolyl nitrogens(the average bond distance of Fe_N is 0.206 4 nm) and two amino nitrogens(the bond distances of Fe_N are 0.218 9 and 0.229 1 nm, respectively) of ligand CTB, there is an uncoordinating benzimidazolyl group expanding in the space, the sixth position is coordinated by one chloride ion(the bond length of Fe_Cl is 0.237 25 nm). So the title complex shows a distortedly octahedral coordination. Following the reaction of oxidative products with thiobabituric acid indicates that the complex can enhance linoleic acid oxidation. Electrospray ionization mass-spectrum in positive ion mode(ESI+) shows that linoleic acid is oxidatively cleft resulting in volatile small molecular fragments, such as malondialdehyde, nonanal, nonenal, malonic acid, hydroxy ethanal and nonanal acid, etc. These aldehydes and ω-oxo acids are important phytoalexins, which can induce biosynthesis of numerous compounds, proteins and enzymes in physiological and pathological signaling systems.

Synthesis and Characterization of a New Mesoporous HPW/SiO₂ Composite Material

SHI Chun-Feng, XIN Ming-Hong, WANG Run-Wei, XIE Ya-Ru, HU Lei, XU Ling, ZHANG Rong-Mei, ZHU Guang-Shan, QIU Shi-Lun

2005, 26(7):  1198-1201. 

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A new mesosilica-encapsulated Keggin type heteropolyacid-HPW/SiO₂ was synthesized by adding HPW into a sol-gel system to form mesoporous silica involving hydrolysis of tetraethyl orthosilicate under the strong acidic synthesis conditions(pH<0). The mesosilica-impregnated heteropolyacid thus synthesized are insoluble and readily separable mesoporous composite materials with uniform mesopores and high specific surface areas. Their structures and physical-chemical properties was characterized by various methods, their catalytic activity were measured by the cracking of cumene and 1,3,5-triisopropylbenzene, and esterification reactions of acetic acid with ethanol and benzoic acid with t-butanol. The results show that the HPW is tightly encapsulated into the network of mesosilica walls and does not leach from the walls of mesosilica. The HPW/SiO₂ composite materials are the promising and new catalysts for acid-catalytic reactions, and the potential replacer of the homogenous reaction catalysts to solve the separation and recycle problems.

Synthesis and Characterization of Novel Covalently Linked Fullerene-porphyrin Compouds

YANG Sen-Gen, LIU Jian-Yong, WU Zhen-Yi, TIAN Ling, FAN Su-Hua, ZHAN Meng-Xiong

2005, 26(7):  1202-1205. 

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In order to construct a donor-acceptor system with efficient electron transfer, a novel covalently linked fullerene-porphyrin ligand(H₂P-C₆₀) was synthesized by 1,3-dipolar cycloaddition reaction of C₆₀, sarcosine and H₂P-CHO, and it's zinc derivative was prepared by metalation of H₂P-C₆₀ and zinc acetate. The two new fullerene-porphyrin compounds were characterized by means of elemental analysis, IR, electronic spectra, ESI-MS and ¹H NMR.They are also predicted to have good optical and electrical properties.

Synthesis, Characterization, DNA-binding and Solvatochromic Properties of a New Ruthenium Complex

WU Bao-Yan, GAO Li-Hua, WANG Ke-Zhi

2005, 26(7):  1206-1209. 

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A new ruthenium complex of -(ClO₄)₂, where bpy=2,2'-bipyridine, dpapz=dipyrido₆-aza-phenazine was synthesized, and characterized by microanalyses, IR and ¹H NMR Spectra. The electronic absorption and emission spectral titration with DNA, DNA competitive binding with ethidium bromide, and viscosity measurements were carried out to study the calf thymus DNA binding properties of -(ClO₄)₂. The solvatochromism of the complex was also studied. The results indicate that the Ru(Ⅱ) complex acts as a DNA intercalator with a binding constant of 6.9×10⁵ L/mol at 50 mmol/L NaCl, and an emission sensor for solvent molecules.

Ion-exchange of Offretites and Their Adsorption Performances to SO₂

LV Xin-Chun, ZHAO Rong, WU Tai-Liu, WANG Li-Ping, SUN Yao-Jun

2005, 26(7):  1210-1214. 

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Offretite(OFF) was synthesized through hydrothermal method, and H-OFF, Li-OFF, Na-OFF, K-OFF, Cs-OFF were obtained by ion-exchange. Subsequently, the samples were characterized by using XRD, SEM, nitrogen sorption, TG/DTA, FT-IR and solid-state ¹H NMR. The structures and morphologies of the samples do not change during the ion-exchange. The thermodynamic properties, surface area, micropore volume and acidic properties change with variation of the cation types in the pores. The results of adsorption of the exchanged zeolites to SO₂ show that Li-OFF exhibits a remarkable adsorption capability at lower pressure.

Synthesis, Characterization, Crystal Structures of Bis(imino)pyridyl Nickel Complexes and Their Catalytic Performance for Ethylene Polymerization

FAN Rui-Qing, ZHU Dong-Sheng, MU Ying, LI Guang-Hua, FENG Shou-Hua

2005, 26(7):  1215-1219. 

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Reactions of equimolar ratios of NiCl₂·6H₂O to the tridentate ligands 2,6-bis[1-(2-methyl-phenylimino)ethyl]pyridine(L¹) or 2,6-bis[(1-phenylimino)ethyl]pyridine(L²) in acetonitrile afford the five-coordinated complexes NiCl₂L¹·CH₃CN(1) and [NiCl₂L²·CH₃CN](2), respectively. All ligands and complexes were characterized by using elemental analysis, IR and ¹H NMR spectroscopy. The structures of complexes 1 and 2 were determined by single-crystal X-ray diffraction. Crystallographic studies on complexes 1 and 2 reveal both complexes to be pentacoordinated with geometries that can be best described as distorted trigonal bipyramidal. Complex 1 crystallizes in the monoclinic system, space group C_c, with a=2.578 3(5) nm, b=1.484 3(3) nm, c=1.586 6(3) nm; β=122.82(3)°, V=5.102 4(18) nm³, Z=4, R₁=0.070 8. Complex 2 belongs to monoclinic system with space group C_c, a=1.577 2(1) nm, b=0.859 4(1) nm, c=1.545 9(1) nm; β=103.27(1)°, (V=2.039 4(2) nm³,) Z=4, R₁=0.037 5. Complexes 1 and 2 exhibit lower catalytic activities for ethylene polymerization upon activation with MAO.

Synthesis and Characterization of Cadmium Orthosilicate Nanowires

CHEN Chen, ZHUANG Zhong-Bin, PENG Qing

2005, 26(7):  1220-1221. 

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A novel type of cadmium orthosilicate nanowire was prepared successfully based on a hydrothermal synthetic process in a mixed water-ethanol solvent system. The composition, morphology, and microscope structure were studied by XRD and HRTEM. From the HRTEM images, these nanowires were found to be composed of Cd₂SiO₃ nanoparticles, which can be called "nanocluster wires". This kind of nanocluster wire will have potential applications and attract increasing interest because it behaves as quantum dots.

Synthesis and Characterization of Iron-included Onion-like Fullerenes

LI Tian-Bao, XU Bing-She, HAN Pei-De, ZHANG Yan, LIU Xu-Guang

2005, 26(7):  1222-1224. 

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Iron-included Onion-like Fullerenes(OLFs) were formed by pyrolysis ferrocene and C₂H₂ in H₂ and Ar streams through a cylindrical furnace with a temperature at 950 ℃ in their center. The resulting carbon structure morphology was influenced by different carrying gases. When proper hydrogen flow was used in the carring gas, the graphitic carbon on the surface of metal catalysts can be easily eached. This etching rate and the catalytic efficiency of metal are two competitive mechanisms in the graphitization processes, that is, when the etching rate of graphitic sheets dominates, iron-included OLFs are apparently the end product. XRD showed that the presenting metal particle is iron carbide. XRD patterns show that the presented metal particle is iron carbide. Raman scattering spectra show that the G peak of iron-included OLFs has slightly upshift from the position 1 582 cm^-1(known for a pure graphite), which was interpreted as an influence of shell curvature. Hollow core OLFs can be obtained after the iron carbide particals were removed by annealing iron-included OLFs at 1 900 ℃ for 4 h.

Coating Process of Silica Film on TiH₂ Particles and Hydrogen Release Characteristics

FANG Ji-Xiang, YANG Zhi-Mao, DING Bing-Jun

2005, 26(7):  1225-1227. 

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The coating process of TiH₂ particles with SiO₂ layers, and the effect of the coating layer on hydrogen release characteristic of TiH₂ powders were studied experimentally. The gelation rate of silicic acid is an important factor for controlling the surface morphologies of coating layers. When the concentration of SiO^2-₃ is about 0.5 mol/L, the condensation rate of silicic acid is appropriate for the formation of a homogeneous and dense coating membrane. The results of hydrogen release at 700 ℃ show that TiH₂ particles coated with silicon dioxide layers can efficiently delay the starting time of hydrogen release of TiH₂ powders to 60-100 s.

Preparation and Performance of p-tert-Butyl-calix[8]-arene-bonded Silica Gel for Capillary Electrochromatography

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

2005, 26(7):  1228-1232. 

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A new method for the preparation of calix-arene-bonded stationary phases(C8BS) was developed via the breaking epoxy group on the solid surface of the bonded 3-glycidoxypropyl silica by using active phenolic sodium of calix-arene in the presence of phase-transfer catalyst, which is moderate and universal. The new method was first introduced to the preparation of calixarene-bond stationary phase for capillary electrochromatography(CEC) with some modification. The new stationary phases were evaluated by the pressurized CEC(pCEC). The results show that the calixarene-bonding can provide lower and stable EOF over a wide pH range from 3-8, and the peak shapes of basic compounds on silica gel matrix can be improved because of the shield effect of the macrocyclic ligand, which are very important to CEC. Additionally, EOF source was studied by using silanization step by step. The result shows that the phenolic hydroxyl groups on the calixarene-bonded stationary phase result in EOF partially, which is consistent with the open-column of CEC reported.

Electron Transfer Process of Dopamine at Mimicking Biomembrane

HU Li-Na, ZHANG Li-Min, LU Xiao-Quan

2005, 26(7):  1233-1236. 

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An electron transfer reaction between ferrocene and dopamine (DA) in a aqueous solution and oxidizing agent in an organic solution immiscible with water was studied by thin-layer cyclic voltammetry(TLCV) for charge transfer on the liquid/liquid(L/L) interface. The bimolecular rate constants(k) were obtained and one electron transfer process on the interface could be observed. The oxidation reaction of DA on the L/L interface by above method was discussed in comparison with the result obtained by scanning electrochemical microscopy (SECM) and got a reasonable agreement between them, which could give a prove to the practicality of TLCV. Otherwise, lower concentration ratios K_r of aqueous to organic reactants were adopted, which gave an evidence to the proposed procedure of Barker.

Preparation of Pyrenebutyric Acid-modified Zirconia-Magnesia Stationary Phase for High Performance Liquid Chromatography and Its Application to the Separation of Fullerenes

YU Qiong-Wei, SHI Zhi-Guo, DA Shi-Lu, FENG Yu-Qi

2005, 26(7):  1237-1241. 

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The zirconia-magnesia composites were modified with pyrenebutyric acid and were used as π^*

Separation, Purification and Structure of Burdock Oligosaccharide

HAO Lin-Hua, CHEN Lei, ZHONG Na, CHEN Kao-Shan, LI Guang-You

2005, 26(7):  1242-1247. 

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A kind of soluble oligosaccharide, Burdock oligosaccharide(BOS₂), was extracted by hot water, deproteinized by enzymolysis and Sevag method, precipated by ethanol, separated and purified by Sephadex G-50 column chromatography from burdock sub-standard root. Its purification, physical and chemical properties and structure were studied by means of some chemical reactions assay and instrumental analysis. The results show that BOS₂ is composed of D-fructose and D-glucose in a molar ratio of about 12∶1, which is confirmed by the composition of 12 fructose residues linked by β(2→1) glucoside bond and 1 glucose residue linked by α(1→2) glucoside bond at the end of linear straight sugar chain. It is shown to be a single homogeneous component.

Quantitative Detection of H-ras Point Mutation in Bladder Cancer by ECL-PCR Method

ZHU De-Bin, XING Da, SHEN Xing-Yan, LIU Jin-Feng

2005, 26(7):  1248-1251. 

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The ability to detect point mutation is of great importance in molecular genetics. However, conventional electrophoresis-based methods often require long time with multi-step, using radioactive isotopes or other hazardous materials, and the result is only semi-quantitive. In this study, an electrochemiluminescence polymerase chain reaction(ECL-PCR) method for quantitative detection of H-ras point mutation was devoloped. The results show that the sensitivity of the assay for H-ras amplicon was 100 fmol and the linear range was from 0.1 to 500 pmol. Twenty bladder cancer samples were tested by using the ECL-PCR assay. The positive rate of H-ras point mutation was 35%. Mutant H-ras amplicon was then quantified according to the calibration curve. In the assay, only 10 μL of sample was used for each test and a 20 min incubation period was required in addition to a 30 s acquisition time. It is significantly better in terms of safety, sensitivity, linear range, and assay time, compared with the traditional methods. The results of the study suggest that ECL-PCR is a feasible quantitative method for rapid screening of a large amount of clinical samples.

Interaction Between Domoic Acid and Double-Stranded Oligodeoxy-nucleotide Studied by Using Microchip-based Non-gel Sieving Electrophoresis

ZHOU Xiao-Mian, LI Da-Zhi, SHEN Zheng, LIU Wei, LI Gui-Ru, LIN Bing-Cheng

2005, 26(7):  1252-1254. 

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The interaction between domoic acid(DA) and 18-mer double-stranded DNA(dsDNA) was investigated by using microchip-based non-gel sieving electrophoresis. For the 18-mer dsDNA with a sequence of 3'-GCATTGGTTGACGTTGCA-5', the amount of free dsDNA decreases with the increase of the added DA and also with the increase of reactive time. Meanwhile, the newly-produced two peaks were observed. The experimental results show that there is a strong interaction between DA and the 18-mer dsDNA. DA makes the degradation of the 18-mer dsDNA. The non-gel sieving electrophoresis on microchip is a rapid, convenient, highly sensitive method for studying the interaction between DNA and small molecules.

Second-order Calibration of Nitrobenzenes Using Alternating Trilinear Decomposition Algorithm Combined with HPLC-DAD

DING Yu-Jie, WU Hai-Long, FANG Dong-Mei, CUI Hui, SUN Xiang-Yu, XIA A-Lin, HU Le-Qian, YU Ru-Qin

2005, 26(7):  1255-1257. 

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High performance liquid chromatography(HPLC) is one of the analytical techniques used most frequently. Its chief limitation lies in the need to avoid the overlap of chromatographic peaks as much as possible. In this paper, the overlapped chromatograms and spectra system of 1-chloro-2,4-dinitrobenzene and 3,5-dinitrobenzoic acid in the presence of 2,4-dinitrobenzoic acid were resolved by using the alternating trilinear decomposition(ATLD) combined with HPLC-DAD. Moreover, both were determined simultaneously, whose recoveries were(102.1±2.2)% and(97.6±3.6)%, respectively. The satisfactory results show that this experiment can be easily performed without paying out time-consuming and complicated procedures and quantifying accurately. It revealed the ATLD algorithm was one of the approaches to solve second-order calibration problem in HPLC-DAD.

Elimination of As(Ⅲ) from Groundwater by Bead Cellulose Adsorbent Loaded with Fe(β-FeOOH)

GUO Xue-Jun, CHEN Fu-Hua

2005, 26(7):  1258-1263. 

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A new adsorbent, bead cellulose loaded with Fe hydroxide(β-FeOOH) was prepared and applied to the removal of arsenite from groundwater. The adsorbent has perfect properties in As(Ⅴ) and As(Ⅲ) adsorption capacity, selectivity and kinetics. There is no need of pH adjusting and preoxidation during the arsenite removal. The adsorbent is porous and has excellent mechanical properties. The adsorbent has a high content of Fe, which is the reactive center with a high reactivity for sorption of arsenite. The sorption kinetic data can be described by the Lagergren pseudo-second order rate equation. Arsenate elimination was favored at pH=6-9. The addition of chloride, sulfate did not affected the arsenite removal efficiency. The column experiment indicated that the breakthrough and saturation capacity were large with high velocity flow and influent arsenite concentration. The adsorbent can be generated with NaOH solutions, and the desorption and regeneration process were effective. The β-FeOOH loaded in the bead cellulose was chemically stable during the column experiment and regeneration.

Composition and Antioxidative Actvity of Polysaccharide from Bergamot

ZHU Xiao-Yan, WU Jian-Min, JIA Zhi-Shen

2005, 26(7):  1264-1267. 

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After being extracted with hot water and precipitated with alcohol, crude polysaccharide was obtained from bergamot. Crude bergamot polysaccharide was gotten rid of proteins then isolated and purified by DEAE-cellulose. Two fractions were obtained and named BP1 and BP2. BP1 and BP2 were shown to be homogeneous on gel filtration chromatogram and polyacrylamide gel electrophoresis(PAGE). The average molecular weights(M_w) of BP1 and BP2 were determined to be 17 773 and 65 589 respectively, by gel permeation chromatography. The components of them identified by TLC and HPLC were rhamnase, mannose, glucose, galactose and xylose. The effects of the polysaccharide on removal of reactive oxygenspecies in some modified chemical systems were investigated by chemiluminescence and spectrophotometry. The inhibition of the damage of DNA chain induced by hydroxyl radical by the bergamot polysaccharide was observed by chemiluminescence. The results show that the bergamot polysaccharide could efficiently remove O^-·₂, HO^. and significantly protected DNA chains from being damaged by free radicals.

Synthesis of Novel Enantiomers Cyclophanes Using 2,2'-Diethynyl-1,1'-binaphthyls as a Structural Block and Their Optical Properties

AN De-Lie, YANG Shao-Hui, ZHANG Zhi-Yang, PENG Zhi-Hong, ZHANG Ying-Jun, LIU Hong-Ling

2005, 26(7):  1268-1272. 

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We employed (R)- and (S)-2,2'-diethynyl-1,1'-binaphthyl with a highly stable chirality as the structural blocks and investigated the synthesis of two topologically interesting tetrabinaphthyl cage compounds (R,R,R,R)-2 and (S,S,S,S)-2 via the multi steps reactions including the introduction of protecting group, linking of benzene-bridge, removal of protecting group as well as intermolecular cross-coupling. As expected, the results from MS, IR, UV-Vis, ¹H, ¹³CNMR, elemental analysis and optical properties indicate that this method is very effective for obtaining compound 2 in enantiomer form. The enantiomer relation of the two isomers was reflected unambiguously by their circular dichroism(CD) spectra with exact mirror images and specific rotations [α]_D data.

Synthesis and Selective Binding for Metal Ion of Double-armed Benzo-15-crown-5

HAN Jian-Rong, ZHANG Heng-Yi, LIU Yu

2005, 26(7):  1273-1276. 

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Two new double-armed benzo-15-crown-5(2 and 3) were synthesized by reaction of 4,5-bis-(bromomethyl)-benzo-15-crown-5 with 2-naphthol and 2-mercaptobenzothiazole, respectively, and characterized by elemental analysis, mass, IR, ¹H NMR spectroscopies and X-ray diffraction, respectively. The crystal structure of compound 2 was reported as follows: Crown ether 2 crystallizes in the monoclinic system, space group P2₁ with cell parameters: a=1.262 2(9) nm, b=1.224 7(9) nm, c=2.016 0(16) nm, β=101.270(15)°. There is an intermolecular π^*

Preparation of Adsorbents for Endotoxin Removal in Hemoperfusion withAmino Acid as the Ligand and Investigations on Their Properties

HOU Guang-Hui, WANG Hui-Yan, LIU Tao, YUAN Zhi, FANG Jie, LI Dong-Hua, QIU Qi, GUO Shi-Duo

2005, 26(7):  1277-1280. 

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Endotoxermia is caused by endotoxin, lipopolysaccharides(LPS) released from gram-negative bacteria cell wall. Endotoxin is composed of a hydrophilic polysaccharide moiety and a hydrophobic lipid moiety(lipid A) that anchors the molecules in the outer membrane. The sugar residues may be partially phosphorylated and serious endotoxin intoxication can cause sepsis and septic shocks, leading to severe hypertension, cardiovascular collapse, multiple organ failure and death. Removal of endotoxin duly and effectually from patients' blood is very important in clinic. In this paper, with agar gel as the carrier and amino acids as the ligands, adsorbents for endotoxin were prepared and their adsorption capacity for endotoxin were compared. The properties of adsorbents were investigated. The adsorbent with L-lysine as the ligand was chosen to be used for hemoperfusion. The adsorbent can remove plasma endotoxin of endotoxemia rabbit model to close to the normal level and the highest clearance percentage reached 73.6%. The adsorbent has a good blood compatibility.

Total Synthesis of 5α-Hydroxy-isopterocarpolone

GUAN Yu-Kun, LI Ping, ZHOU Gang, GAO Xiao-Lei, LI Yu-Lin

2005, 26(7):  1281-1283. 

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The first total synthesis of (+)-5α-hydroxy-isopterocarpolone (1), an oxygenated eudesmane isolated from Chinese folk medicine Artemisia eriopoda, starting from (+)-dihydrocarvone(2) was described. Compound 4 was stereoselectively prepared from compound 2 in three steps according to reference[7]. The treat_ment of tosylhydrazone 5, which was formed via the reaction of compound 4 and TsNHNH₂ catalyzed by BF₃·Et₂O, with an excess of n-butyllithium gave triene 6. Oxidation of triene 6 with singlet oxygen afforded the desired endo-peroxide 7 as a single product. Reductive cleavage of peroxide 7 with K₂CO₃ gave α-rotunol 3, a natural eudesmane firstly isolated in 1969. Hydrolysis of α-rotunol 3 with 10% sulfuric acid afforded (+)-5α-hydroxy-isopterocarpolone (1). The structures of all the compounds were confirmed by IR, MS and NMR spectra.

DFT Study on Electronic Spectrum Property for B(C₂H₅)₂q and Its Derivatives

TAN Ke, TENG Yun-Lei, KAN Yu-He, YANG Shuang-Yang

2005, 26(7):  1284-1286. 

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The molecular structures of the ground state and the first singlet excited state for B(C₂H₅)₂q and its derivatives were optimized with the DFT B3LYP method and ab initio "configuration interaction with single excitations" (CIS) method respectively. Time Depended Density Function Theory (TD-DFT) B3LYP was employed to investigate electronic spectrum properties of B(C₂H₅)₂q and its derivatives. It was found that the luminescence originates from the π^*

Theoretical Study on Conformations and Energies of 2,4-Difluoropentane

ZHANG Zhi-Jie, Lü Zhong-Yuan, LI Ze-Sheng, SUN Chia-Chung

2005, 26(7):  1287-12899. 

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Geometries and energies of the conformers of stereoisomers of 2,4-difluoropentane with various low-energies are determined at the MP2 level with 6-311++G^** basis set. The strong electronegative fluorine biases the equilibrium structures. Furthermore, the long range nature of coulombic interaction induces the correlation between the atoms separated over 3 bonds.

Characterization of V_mTi and K_nV_0.04Ti Catalysts Supported by Oxide and Their Catalytic Performances for Diesel Soot Combustion

LIU Jian, ZHAO Zhen, XU Chun-Ming

2005, 26(7):  1290-1293. 

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Two systems of V_mTi and K_nV_0.04Ti catalysts were prepared by incipient-wet impregnation method and their catalytic performances for diesel soot combustion were investigated by using temperature-programmed oxidation(TPO) reaction. The results show that the V_0.04Ti catalyst has a good activity for diesel soot combustion(t_m=389 ℃). The addition of potassium to VO_x/ TiO₂ catalysts can apparently improve their catalytic activities for soot oxdation. And when n(K)∶n(V)∶n(Ti)=(0.04∶0.04∶1,) the catalysis activity is the best, and the temperature of soot combustion reaction is the lowest reaction temperature(t_m=343 ℃). The structural characterization results by FTIR and UV-Vis reveal that V₂O₅ formed on the surfaces of the V_mTi catalysts when m exceeded 0.04. The (K_0.04V_0.04Ti) catalyst has a highest catalytic activity. It is due to the formation of KVO₃ which has a good synergetic effect with TiO₂ support in the catalyst.

Surface Photovoltaic Response and Electric-field Action of a New aza H₂Pc Containing Four 1,10-Phenanthroline Subunits

HOU Xiao-Ke, DU Xi-Guang, MA Chun-Yu, LI Yan, ZHANG Qing-Lin, WANG Xu, CHANG Yu-Chun, JIANG Wen-Hai, SHAN Shi-Jun, JIANG Xiu-Ying, DU Guo-Tong

2005, 26(7):  1294-1297. 

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In this paper an aza H₂Pc containing four 1,10-phenanthroline subunits was presented and its photoluminescence and photovoltage properties were investigated. For the same kind of electronic transition(π^*

Synthesis and Characterization of a Novel Benzoxazine Without β-Hydrogen and Its Catalytic Curing Reaction

CAO Hong-Wei, XU Ri-Wei, ZHANG Bing-Wei, DING Xue-Jia, YU Ding-Sheng

2005, 26(7):  1298-1303. 

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With substituted bisphenol A[2,2-bis(4-hydroxy-3-allylphenyl)propane], paraformaldehyde, and allylamine as the starting materials, a novel benzoxazine precursor without β-hydrogen is developed by a solventless procedure. The molecular structure is verified by FTIR, ¹HNMR, GPC and EA. It is confirmed that there are three reactive groups on the benzoxazine structure: N-allyl, Ar-allyl, benzoxazine ring. As the ortho and para positions on the phenol are occupied by different groups, it is quite significant to investigate the reaction of the three groups. So we synthesize some other kinds of benzoxazine, isothermal differential scanning calorimetry(DSC) and Fourier transform infrared(FTIR) are used to determine the detailed reactions of the three groups. It indicates that N-allyl and benzoxazine ring react nearly at the same temperature(about 246 ℃), and Ar-allyl reacts at about 350 ℃. Further more, with two different kinds of catalysts, the as-synthesized benzoxazine precursor is also studied by DSC and FTIR to determine the influence of the catalysts on curing. Among the catalysts tested, Lewis acids show promising results, while phenolic catalysts can also decrease the onset curing temperature of the benzoxazine ring. Choosing one sample catalyzed by TiCl₄, the curing reactions are discussed at different temperatures by FTIR and a mechanism of the benzoxazine precursor catalyzed by TiCl₄ is suggested.

Electrocatalytic Properties of Multi-wall Carbon Nanotubes-supported PtSn Anodic Catalyst for Ethanol Electro-oxidation

ZHAO Xin-Sheng, SUN Gong-Quan, JIANG Lu-Hua, MAO Qing, XIN Qin, YI Bao-Lian, YANG Shao-Hua

2005, 26(7):  1304-1308. 

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Multi-wall carbon nanotubes(MWNTs)-supported PtSn anodic electrocatalyst was prepared for direct ethanol fuel cell(DEFC). TEM image and XRD patterns reveal that PtSn/MWNTs catalyst exhibited a high and homogeneous dispersion of metal particles with a narrow particle size distribution range from 1.5 to 6.5 nm, and the mean particles size was about 3.6 nm. The results of cyclic voltammetry(CV), chronoamperometry(CP) and single cell indicated that the PtSn/MWNTs presented a higher activity toward ethanol electro-oxidation than that of PtSn/XC-72 catalyst. The high performance could be attributed to the unique structure, higher electric properties of MWNTs, compared with that of carbon black XC-72 as the support.

Preparation of Micrometer-and Nanometer-sized Hollow Nickel Spheres by Autocatalytic Reduction

DENG Yi-Da, ZHAO Ling, LIU Xi, SHEN Bin, LIU Lei, HU Wen-Bin

2005, 26(7):  1309-1312. 

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A facile, novel and low-cost method for synthesizing hollow nickel spheres is reported in this paper. The hollow nickel spheres were characterized by field emission scanning electron microscopy, transmission electron microscope and X-ray powder diffraction. And the factors responsible for the control of the size distribution of the hollow spheres were discussed. The hollow nickel spheres was prepared by autocatalyzing the redox reaction around the colloidal particles. The concentration of reaction solution and molar ratio of Ni²⁺ to NaOH are important factors that affect the size distribution of the nickel spheres, and this two processing parameters can be regulated to synthesize micrometer and nanometer-sized hollow nickel spheres.

DFT Theoretical Study on Mechanism of Indole Formation from Aniline and Glycol

SUN Ren-An, LIU Hong-Yan, ZHANG Xu, HAN Ke-Li

2005, 26(7):  1313-1316. 

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The general transition state theory was applied to study the mechanism of indole formation from aniline and glycol. First, four possible reaction paths were projected according to that the dehydration and dehydrogenation are the essence of this reaction. Then, the geometries of all reactions, immediates, impossible transition states and products were optimized, and the transition states of each basic reaction were obtained. In the same time the active energies of all basic reactions were obtained from the calculation. At last, the main reaction channel was given by analysis and comparison. Following that, the reaction mechanism was studied when the catalyst was added. The active energy decreases because of the existence of the catalyst.

Effect of Rapid Quenching Speed on the Structure and Catalytic Properties of the Skeletal Ni Catalysts

HU Hua-Rong, FANG Jing, QIAO Ming-Hua, YAN Shi-Run, FAN Kang-Nian, LI He-Xing, ZONG Bao-Ning, ZHANG Xiao-Xin

2005, 26(7):  1317-1320. 

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A series of rapidly quenched skeletal Ni catalysts were prepared by alkali leaching of Ni-Al alloys solidified at different cooling rates. It has been found that the higher cooling rate leads to more residual Ni₂Al₃ phase, lower surface area, larger average pore size and porosity, smaller mean crystallite size, larger unit-cell parameter and more uniform active site. The relationship between the structure and catalytic behavior of the rapidly quenched skeletal Ni was discussed by using cinnamaldehyde selective hydrogenation as the probe reaction.

Studies on the Acute Toxicity of Lu(NO₃)₃ by ¹H NMR and Pattern Recognition Method

WU Hui-Feng, ZHANG Xiao-Yu, LI Xiao-Jing, SUN Guo-Ying, WU Yi-Jie, PEI Feng-Kui

2005, 26(7):  1321-1324. 

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¹HNMR spectroscopy and pattern recognition method were used to assess acute toxicological effects of rare earth. Male Wistar rats were treated with Lu(NO₃)_-3 at doses of 0.2, 2.0, 10 and 100 mg/kg body weight with NaCrO₄, HgCl₂, CCl₄, ANIT and N₂H₄₅HCl as the model toxins. The urine samples from the rats dosed with these compounds were collected over a 48 h time course and analyzed by 600 MHz ¹HNMR spectra. Each NMR spectrum was data-processed to provide 220 intensity-related descriptors of spectra. The urine spectral data were analyzed by SIMCA method and successful classification of the toxicity and biochemical effects of Lu(NO₃)₃ were achieved. The toxicity induced by lower doses(0.2 and 2 mg/kg body weight) of Lu(NO₃)₃ was classified to NaCrO₄ which produced lesion to proximal convoluted tubule cells, and the higher doses(10 and 100 mg/kg body weight) of Lu(NO₃)₃ could cause liver centrilobular necrosis like CCl₄.

Nano-structural Characters of Highly Active and Stable Ni/ZrO₂ Catalyst for CO₂ Reforming of Methane

LI Yan, WANG Yu-He, XU Bo-Qing

2005, 26(7):  1325-1329. 

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Ni/ZrO₂ catalysts with different phase compositions and crystal sizes of ZrO₂ nanoparticles were prepared and used to catalyze the methane reforming reaction with CO₂. Catalyst characterizations with XRF, XRD, TEM, TPR and H₂-TPD show that highly active and stable Ni/ZrO₂ catalysts are nanocomposites of comparably sized metallic Ni and ZrO₂ nanoparticles. The phase composition of ZrO₂ in the catalysts has little effect on the catalytic stability.

Preparation of Pyrene Nanomaterials with Different Mophologies in a Surfactant Solution

ZHANG Xiu-Juan, ZHANG Xiao-Hong, WU Shi-Kang,

2005, 26(7):  1330-1333. 

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Pyrene nanomaterials with different morphologies are obtained by template method in an aqueous CTAB system. We found that the as-prepared nanomaterials with different morphologies(nanorods and nanoparticles) exhibited different properties. The mechanism of the preparation was also simply analyzed and discussed.

Effect of Difference of Modifiers' Chain on Size and Optical Property of Core-shell CdS Nanocrystals

LOU Wen-Jing, CHEN Miao, LIU Wei-Min, XUE Qun-Ji, ZHOU Xiang-Ke

2005, 26(7):  1334-1337. 

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Core-shell CdS nanocrystals, which were modified by different-chain length alkyl thiols, were chemically synthesized by a new liquid-liquid two-phase method. The structure and composition were investigated with UV-Vis absorption spectra, X-ray diffraction, and transmission electron microscopy. The results showed these as-prepared samples consisting of a nano-CdS core and a capped-layer of thiols chemically absorbed on the surface, and the modifiers had a great effect on the size and optical property of the inorganic nano-core. According to further analysis, it was found that the size of CdS nano-core had a quasi-parabola relation with the chain length of the modifiers, which was caused by the competitive result of the surface mobility and self-assembly order of the modifiers in the course of nucleation and growth of CdS nano-core

Structure, Composition and Corrosion Resistance of Mg Alloy Anodized Film

QIAN Jian-Gang, LI Di, WANG Xue-Li, GUO Bao-Lan

2005, 26(7):  1338-1341. 

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The kinetics of film-forming course, the surface morphology, structure, composition and valence of element, phase constituent and the corrosion resistance of anodic films were studied by the ways of voltage-time curve, thickness-time curve, SEM, EDS, XPS, XRD, total immersion test and polarization curve respectively. The results show that there are relativity among the structure, composition and corrosion resistance of anodic films on AZ91D Mg alloy; the film-forming course can be divided into four stages, and the corrosion resistance of the anodic films in different stages have great difference because of its variation of thickness, structure and composition; the films that have the best corrosion resistance is the films formed on the boundary of stages Ⅲ and Ⅳ during the anodic course. The anodic oxidation film contains Mg, O, Si, B and a small amount of Al and Na. The dense layer is composed mainly of MgO, while the porous layer is composed of MgO, MgSiO₃ and Mg₃B₂O₆.

Fabrication, Characterization and Electric Properties of a Gold Nanowire Containing 4,4'-Azopyridine Molecular Junction

XIANG Juan, LIU Bo, TIAN Jing-Hua, WU Sun-Tao, HU Jia-Wen, TIAN Zhong-Qun

2005, 26(7):  1342-1344. 

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A study on the fabrication and characterization of gold nanowires containing a 4,4'-azopyridine monolayer junctions was reported. Au nanowires were prepared by using a two-step alternative current(AC) electrodeposition inside the pores of AAO. Azopyridine molecules were adsorbed on the top of Au layer by self-assembly and electroless plating was done to introduce Au caps on the top of the SAMs. The top Au segments were prepared by using AC electrodeposition, too. The HRTEM image shows the thickness of the SAM is approximately 1.5 nm, which is in good agreement with the theoretical length of azopyridine. It is demonstrated that direct AC electrodeposition was more effective than chemical deposition on strengthening the electronic device. Utilizing 4,4'-azopyridine as the active component, current-voltage characterization of nanowires containing molecules was done at room temperature by a two-point probe method by using a Keithley 4200 semiconductor characterization system. A good conductive behavior at room temperature in this electronic device was observed.

Pt Catalyst Supported on Carbon Nanotubes for Selective Hydrogenation of Citral and Differential Heats of CO Adsorption

ZHANG Yao-Jun, LI Ju-Yuan, LI Wen-Zhen, XIN Qin

2005, 26(7):  1345-1347. 

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Carbon nanotube is found to be a novel support for the selective hydrogenation of citral in this paper. Selective hydrogenation of citral was carried out in an autoclave at 5 MPa and 323 K. The results indicate that the selectivity of the products, unsaturated alcohols, is about 86 over Pt/CNTs catalyst and 48 over Pt/XC-72 catalyst, respectively. The differential heat of CO adsorption measured by microcalorimetry is firstly used to probe surface adsorption sites of platinum catalyst supported on carbon nanotubes. The experimental results indicate that the Pt/CNTs catalyst shows a higher initial differential heat of CO adsorption(126 kJ/mol) than the Pt/XC-72 catalyst(106 kJ/mol).

Phase Diagram of Poly(acrylamide)-poly(ethylene glycol)-water and Partition Coefficient of Acrylamide

SHAN Guo-Rong, CAO Zhi-Hai, HUANG Zhi-Ming, WENG Zhi-Xue

2005, 26(7):  1348-1351. 

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It is found that when the two aqueous solutions of poly(acrylamide)(PAAm) and poly(ethylene glycol)(PEG) are mixed, an aqueous two-phase system can be formed. The top is the PEG-rich aqueous phase and the bottom is the mixture of rich PAAm and PEG aqueous phase. The phase diagrams of this system are made with gel permeation chromatography(GPC) and turbidity titration methods. As the molecule weight of PEG increases, the critical concentration of phase separation becomes lower. As the temperature of this system increases, the critical concentration of phase separation decreases at first, but when the temperature is higher than 55 ℃, it increases again. Acrylamide(AAm) can be partitioned in PAAm-PEG-H₂O aqueous two-phase system, the partition coefficient(K) of AAm in this system increases with increasing the temperature of phase equilibrium and the PAAm concentration, but decreases with increasing the PEG concentration.

Preface

Preparation of Raspberry-like SiO₂/PMMA Nanocomposite Spheres

CHEN Min, YOU Bo, ZHOU Shu-Xue, WU Li-Min

2005, 26(7):  1352-1355. 

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Water-borne raspberry-like silica/PMMA nanocomposite particles were prepared via a free radical copolymerization of MMA(methyl methacrylate) with 1-VID(1-vinylimidazole) in the presence of ultrafine aqueous silica sols. The silica needn't be pretreated or modified and no surfactant was added in this preparation method. The strong acid-base interaction between the surface hydroxyl groups of silica particle with 1-VID was strong enough for promoting the formation of long-stand stable silica/PMMA nanocomposite particles. The average particle sizes of the obtained nanocomposite particles ranged from 120 nm to 350 nm, depending on the precise formulation. Thermogravimetric analysis indicates the silica content in the nanocomposite particles ranged from 15 to 20. TEM and SEM indicate a raspberry-like morphology of the nanocomposite particles.

Articles

Preparation and Permeation Properties of Molecularly Imprinted Polymer Membranes with Norfloxacin as Template

LU Chun-Yang, MA Xiang-Xia, HE Xi-Wen, LI Wen-You, CHEN Lang-Xing, HE Hai-Cheng

2005, 26(7):  1356-1359. 

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Using polyvinylidene fluoride microporous-membrane as the supported membrane and the medicine norfloxacin as the template, the molecularly imprinted membranes were prepared via in-situ polymerization by UV irradiation. The interaction between the template molecule norfloxacin and the functional monomer was evaluated by UV spectrum titration. The membranes' surface features were analyzed by scan electron micrography. The selective permeation experiment via the mixed substrates shows that there were paths in the molecularly imprinted membranes which were formed by the cavities with size and functional groups accommodated to the template norfloxacin and showed better a permeation selectivity for the template.

Properties of Photo-responsive Superhydrophobic Azobenzene Multilayers Fabricated by Electrostatic Self-assembly

JIANG Wu-Hui, WANG Guo-Jie, HE Ya-Ning, AN Yong-Lin, WANG Xiao-Gong, SONG Yan-Lin, JIANG Lei

2005, 26(7):  1360-1362. 

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Azobenzene multilayers were fabricated on silicon substrates by electrostatic self-assembly technology. Rough silicon substrates were prepared by photolithography and the inductive coupling plasma deep etching technique. Surface morphology and properties of azobenzene multilayer on the silicon substrate were characterized by SEM, UV-Vis spectra and contact angle(CA) measurement. Superhydrophobicity(CA is larger than 150°) on the multilayer was obtained by introducing geometrical structure onto the substrate surface. For the flat silicon substrate, CA on 10 bilayers was 83.4°±2.1°. For the rough substrate, CA was 150.9°±1.7°. After UV irradiation the CA decreased. A large reversible CA change about 37° was realized through ultraviolet and visible irradiation on the rough azobenzene film, comparing with that about 5° on the flat film. These results indicate that the surface roughness plays an important role in tuning surface wettability. Moreover, the reversible switching by photo-irradiation could be realized many times, and a good reversibility of surface wettability was observed.

Preparation of Starch-g-Sodium Acrylate/Acrylamide Superabsorbent via Frontal Polymerization

YAN Qing-Zhi, SU Xin-Tai, ZHANG Wen-Feng, GE Chang-Chun

2005, 26(7):  1363-1365. 

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A new method for the preparation of a starch-graft-sodium acrylate-co-acrylamide superabsorbent using a thermal propagating front was described. The frontal polymerization(FP) is a simple mode of polymerization in which a localized zone of reaction propagates in an unstirred medium, converting monomer to polymer. Because no additional heat is needed after the initial application, the process has potential advantages over traditional polymerization methods: lower processing costs, faster reaction rate, and less energy input. These advantages make the frontal polymerization a potential viable option in polymer synthesis. Scanning electron microscope picture shows that porous superabsorbent can be synthesized by FP. The superabsorbent swelled fast with high water and salt solution absorbency.

Crystal Structure of 5[(4'-Heptoxy-biphenylyl-4-yl)oxy]carbonyl-1-pentyne

LIU Lei-Jing, GENG Jian-Xin, ZHOU Yun-Chun, YIN Li, LI Gao, ZHOU En-Le, Jacky Lam Wing Yip, Tang Ben-Zhong

2005, 26(7):  1366-1368. 

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The crystal structure of 5[(4'-heptoxy-biphenylyl-4-yl)oxy]carbonyl-1-pentyne(A3E'O7) was investigated by wide angle X-ray diffraction(WAXD), transmission electron microscope(TEM) and atom force microscope(AFM). The structures of A3E'O7 solution-crystal and melt-crystal are the same. The crystals belong to the monoclinic P112/m space group, the cell parameters are a0.589 nm, b0.771 nm, c4.75 nm, αβ90° and γ93.8°, the calculated cell density is 1.167 g/cm³.

Preparation and Characterization of Drug-loaded PLA/PEG/PLA Triblock Copolymer Nanocapsules

NIU Wen-Qiang, FU Guo-Qi, WU Jun-Li, SHI Ke-Yu, YUAN Zhi, HE Bing-Lin

2005, 26(7):  1369-1371. 

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Biodegradable triblock copolymer PLA/PEG/PLA was synthesized by ring-opening bulk polymerization of D,L-lactide in the presence of poly(ethylene glycol) (PEG), in the molecular structure of which, the length of PEG and PLA chain segments was made to be quite different. Nanoparticles were prepared by using the copolymer via a double emulsion-evaporation technique. The paticles tended to form the configuration like capsules, i.e., the nanocapsules, because of the great size difference in PEG and PLA segments of the copolymer. Insulin, chosen as a model drug, was encapsulated into nanocapsules. The effect of preparation conditions on the size, insulin encapsulation efficiency, and in vitro drug release behavour of the nanoparticles were investigated. The experimental results show that the nanocapsules had a smooth spherical surface and the mean diameter was in the range from 180 nm to 350 nm, and the entrapment of insulin achieved up to 78.4. The drug-loaded nanocapsules released their content continuously, remarkably different from the corresponding micelles which gave a significant initial burst release followed by a slow release.

Synthesis and Characterization of PPTA/MgAl-LDH Nanocomposite by in situ Polymerization

GUO Bing-Zhi, JIAO Qing-Ze

2005, 26(7):  1372-1374. 

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A poly(p-phenylene terephthalamide)(PPTA)/MgAl layered double hydroxides(MgAl-LDH) exfoliation nanocomposite was synthesized by in situ polymerization of p-phenylenediamine with terephthalate-pillared hydroxides, Mg₄Al₂(OH)₁₂[C₆H₄(COO)₂]. The samples thereby obtained were characterized by X-ray diffraction, transmission electron microscopy image and thermal analysis. The results show that the layers of terephthalate-pillared hydroxides are exfoliated and dispersed disorderly in the PPTA matrix, the crystallinity of nanocomposite was improved compared with the original PPTA. Thermogravimetric analysis indicates that the thermal stability of PPTA/MgAl-LDH decrease to a certain degree.

Mechanical Property and Microstructure of Biological Material of Calcium Phosphate Cement/Polypeptide Copolymer

ZHANG Su-Ning, LIN Jia-Ping, CHEN Tao, LIU Chang-Sheng

2005, 26(7):  1375-1377. 

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Polypeptide graft copolymers such as poly(γ-benzyl-L-glutamate)(PBLG)-poly(ethylene glycol)(PEG) and poly(γ-ethyl-L-glutamate)(PELG)-poly(ethylene glycol)(PEG) were introduced into self-setting calcium phosphate cement(CPC) system to improve its mechanical properties. The compression strength was improved considerably by the induction of polypeptide copolymers. It is about 22.3 higher for PBLG-g-PEG and 65.0 higher for PELG-g-PEG, respectively. The results also show that for the same polypeptide copolymer, higher compression strength of composites can be obtained by introducing copolymer micelles into the CPC. According to the results of scanning electron microscope(SEM), the crystallite shapes of CPC depend on the weight fraction of polypeptide copolymer in the composites.

Synthesis and Characterization of a Novel Fluorine-contained Poly(Aryl Ether Ketone) Containing 1,4-Naphthylene Units

ZHANG Yun-He, WANG Dong, NIU Ya-Ming, WANG Gui-Bin, JIANG Zhen-Hua

2005, 26(7):  1378-1380. 

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A novel bifluoro-monomer containing naphthalene moieties was synthesized and characterized by using FTIR, MS and NMR. Different poly(aryl ether ketone)s based on 1,4-bis(4,4'-fluorobenzoyl) naphthalene were prepared via aromatic nucleophilic substitution reaction. The polymers with a high molecular weight can be readily obtained due to the highly activity of the used monomer. 3F-PEEK-nK and 6F-PEEK-nK polymers were determined to exhibit good thermal stabilities with high T-g of 450 K and 457 K, respectively. Moreover, these polymers show a satisfactory solubility and can be cast into flexible and transparent films.

Synthesis of the Novel Inorganic-organic Hybrid Material with Polymer Metal Complex by Atom Transfer Radical Polymerization

LI Hong-Tu, ZHANG Hong-Wen, XU Ya-Xin, ZHANG Kai, JIN Xu, ZHOU Xin, WANG Jing-Yuan

2005, 26(7):  1381-1383. 

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The homopolymer brushes of polyacrylamide(PAAM) on spherical silicon gel were synthesized by atom transfer radical polymerization(ATRP). The silicon gel initiator was prepared by self-assemble. Utilizing these modified silicon gel as the substrate, a kind of novel inorganic-organic hybrid material with the polymer metal complex was synthesized. The result of ESR indicates that the inorganic/organic hybrid material with the polymer metal complex based on silicon gel possesses well paramagnetis.

Preparation and Characterization of Cross-linked Hollow Poly(lactic acid) Microspheres

JIANG Bing-Bing, GAO Chang-You, SHEN Jia-Cong

2005, 26(7):  1384-1386. 

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Poly(lactic acid) macromonomer with a double bond at its end was synthesized by ring open polymerization of lactide catalyzed by stannous chloride in the presence of allyloxylethanol(AOE) as a co-initiator. Its molecular weight was decreased along with the adding amount of AOE. Initiated by an oxidation-reduction system, e.g. K₂S₂O₈ and Na₂SO₃, the poly(latic acid) macromonomers were copolymerized with divinylbenzene and methacrylic acid in a water-in-oil-in-water emulsion manner to produce hollow microspheres with a size of hundreds nanometers. Their hollow structure was confirmed by transmission electron microscopy. Infrared spectroscopy measurement shows that the remainings of the microspheres after tetrahydrofuran extraction, constituting roughly 20 of the sphere's mass, contained all the initial monomer components. This provides a new pathway for fabricating biodegradable hollow microspheres with rather smaller size, which may find diverse applications in the fields of drug delivery, tissue engineering and nanotechnology.