Table of Content

10 April 2010, Volume 31 Issue 4

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Content of Chemical Journal of Chinese Universities Vol.31 No.4(2010)

2010, 31(4):  0. 

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Letters

New Method for Dynamic Visualization of Poliomyelitis Virus Infection Process

WANG Ping-Cui, XIE Hai-Yan*, ZHOU Xi-Ye, WANG Yang

2010, 31(4):  629-631. 

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The propagative polioviruses were modified with biotin firstly and then labeled with quantum dots through biotin-streptavidin system. On the basis of the strong fluorescence intensity and high photostability of quantum dots, a new method for long-term tracking of single-viruses was established with a live-cell confocal microscope imaging system. The results of the real-time dynamic imaging of QDs-labeled poliovirus showed that the entry process of QDs-labeled poliovirus was rapid and actin-dependent. The method is simple and versatile. It can be applied to the study of infectious mechanism of all kinds of enveloped viruses.

Organic Two-photon Fluorescence Nanoparticles for Cell Stains

XU Hong*, YANG Shu-Min, CHEN Geng, TIAN Lei-Lei, HE Feng, WANG Guang-Yi*, ...

2010, 31(4):  632-634. 

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Two-photon absorption materials offer great promise as the new generation of fluorescent probes to image and study biological processes. We present water-dispersed two-photon functional organic nanoparticles which have been fabricated via reprecipitation method based on two-photon absorbing molecule 2,5,2′,5′-tetra(4′-N,N-diphenylaminostyryl)biphenyl(DPA-TSB), aiming to increase active dye loading density and enhance sensitive bioimaging in the microscopic level. In vitro confocal microscopy has demonstrated that these nanoparticles are avidly internalized into cells with bright fluorescence. The good cell membrane permeability of two-photon functional DPA-TSB nanoparticles make them use as bioimaging staining agent for the deeper tissue.

Articles

Synthesis and Characterization of a Novel Microporous Framework Stannosilicate

ZHANG Lin, HE Dong-Liang, ZOU Yong-Cun, MA Shu-Jie, XIAO Feng-Shou*

2010, 31(4):  635-637. 

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A novel microporous framework stannosilicate was  hydrothermally synthesized and characterized by XRD, SEM, ²⁹Si MAS NMR, ¹¹⁹Sn MAS NMR, IR and TG techniques. The results   show that sample with six-coordinative Sn atoms has the same topology with zirconosilicate mineral litvinskite. XRD peaks indicate that the sample has the same topology with zirconosilicate mineral litvinskite; SEM images exhibit that the sample has similar morphology with size of 10—50 μm; NMR results show that the sample has six-coordinative Sn atoms; IR spectrum indicates that there two bands at 615 and 544 cm^-1 associated with Sn—O stretching freqencies; TGA curve gives mass loss at 9.2% in the range of 35—800 ℃, assigned to adsorbed water at 35\_100 ℃ and framework water at 100\_800 ℃, respectively.

Preparation, Crystal Structure and Thermal Behavior of K(FOX-7)·H2O

XU Kang-Zhen*, ZUO Xian-Gang, SONG Ji-Rong, WANG Feng, HUANG Jie, ...

2010, 31(4):  638-643. 

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A high-energy organic potassium salt of 1,1-diamino-2,2-dinitroethlyene(FOX-7) was synthesized by mixing FOX-7 and KOH in water-methanol system. Crystal structure of K(FOX-7)·H₂O was determined by X-ray diffraction analysis. The crystal belongs to triclinic crystallographic system, space group P1 and cell parameters: a=0.7493(2) nm, b=0.9767(3) nm, c=2.0035(5) nm, α=90.017(4)°, β=97.129(4)°, γ=90.019(4)°, V=1.4548(7) nm³, D_c=1.865 g/cm³, μ=0.724 mm^-1, F(000)=832, Z=8, R₁=0.0523, wR₂=0.1082. The thermal behavior of K(FOX-7)·H₂O was studied, and the apparent activation energy and pre-exponential factor of the second decomposition reaction are 135.9 kJ·mol^-1 and 1012.17s^-1, respectively. The critical temperature of thermal explosion is 212.02 ℃. The specific heat capacity of K(FOX-7)·H₂O was determined with micro-DSC method, and the molar heat capacity is 210.88 J·mol^-1·K^-1 at 298.15 K. Thermodynamic functions of K(FOX-7)·H₂O, relative to the standard temperature 298.15K, were calculated through thermodynamic relationship, and the adiabatic time-to-explosion also was obtained as a certain value between 15.7—16.8 s.

Hydrothermal Preparation and Optical Properties of ZnS∶Cu,Al Nanocrystals Excited by X-ray

XIN Mei*, CAO Wang-He

2010, 31(4):  644-648. 

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ZnS∶Cu, Al nanocrystals were hydrothermally prepared at 200 ℃ and their photoluminescence(PL) and X-ray excited luminescence(XEL) properties were investigated. The effect of further annealing was also studied in detail. The average gain size of the samples with n(Cu)/n(Zn)=3×10^-4 and n(Cu)/n(Al)=2, which was directly hydrothermal-treated at 200 ℃ for 12 h, is about 15 nm; the spherical-like nanocrystals with well dispersity and narrow gain size distribution show cubic structure. The PL and XEL spectra of all of the samples show a broad emission band. The maximum PL and XEL intensities are observed for sample with n(Cu)/n(Zn)=3×10-4 and n(Cu)/n(Al)=0.5. The XEL peak center is at about 470 nm. In this condition, the XEL intensity of the sample which was hydrothermally treated at 200 ℃ for 3 h then annealed in Ar at 800 ℃ for 1 h is enhanced and the peak is located at 520 nm. In the meantime, the XEL intensity is about eight times by comparison with that of the samples without annealing. The particles′ agglomerate size is about 200—500 nm and roughly spherical particles show pure hexagonal structure. The samples with highly luminescence efficiencies and the smaller size could enhance the resolution of imaging systems. By comparing the PL and XEL spectra, the luminescence mechanism and different excitation mechanism of PL and XEL and effect of annealing on XEL were also discussed.

Synthesis of AMS-8-NH2 and Its Loading-release of Oligodeoxyneucleotide

CHEN Min-Min, ZOU Yong-Cun, MENG Yun-Jun, ZHANG Qi, ZHANG Zhuo-Qi, CAO Xi-Chuan

2010, 31(4):  649-652. 

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Mesoporous silicas of AMS-8-NH₂ have been synthesized with the anionic surfactant N-myristoyl-L-glutamic acid sodium(C₁₄ GluA-Na) and 3-amino propyltrimethoxy silane(APS) as co-structure-directing agents(CSDA). The materials were characterized by powder X-ray diffraction(XRD), N₂ adsorption/desorption analysis and ²⁹Si magic angle spinning nuclear magnetic resonance(MAS NMR). The results exhibit that the structure of AMS-8-NH₂ has a long range order of three-dimensional cage-like connecting aperture with about 3.2 nm pore diameter and 706 m²/g special surface area respectively nano-hole material. Organic amine groups have anchored chemically to the surface of material through chemical bonding, whose coverage has reached 25%. The resulting AMS-8-NH₂ materials were used as vehicles and herring sperm oligodeoxyneucleotide(ODN) as a model biological molecule for discussing the loading and release character of ODN on AMS-8-NH₂. The loading experiment shows that when the solution concentration is fixed, the higher solution acidity, the higher loading capability and the maximum amount can reach 214 mg/g at pH=4.7. Among the release process, high sustained release effect of ODN on materials is displayed, which is controlled by environmental pH value. The greater the pH value, the higher the release amount.

Investigation on Magnetic Properties and Thermal Stability for Nanocrystalline γ′-Fe₄N Thin Films

WANG Li-Li, AN Tao, SONG Li-Jun, WANG Xin, GONG Jie, ZHENG Wei-Tao*

2010, 31(4):  653-656. 

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Nanocrystalline γ′-Fe₄N thin films were synthesized on single crystal Si(100) substrate by facing target magnetron sputtering and were heat-treated in vacuum at different temperatures of 300, 400, 500, 600, 700 and 800 ℃ in order to investigate their thermal stability. The structure, morphology and magnetic properties were characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM) and vibrating sample magnetometer(VSM), respectively. The results indicated that Fe₈N capsule layer was formed at the interface of γ′-Fe₄N grain between the heat-treating temperature of 300 and 500 ℃. At heat-treating temperature of 600 ℃, the Fe₈N phase layer tended to decompose to the more stable phase α-Fe. The complete phase transformation from nanocrystalline γ′-Fe₄N phase to α-Fe phase occurred at 700 ℃. The obvious changes of the structure and soft ferromagnetic properties were not found under the temperature of 600 ℃.

Photoacoustic Study of Y³⁺, Tb³⁺ and Er³⁺ Complexes with Aminobenzoic Acid Co-doped Silica Samples

YANG Yue-Tao*, WANG Hai-Yan, LIU Xiao-Jun, ZHANG Shu-Yi

2010, 31(4):  657-661. 

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Lanthanide complexes Tb(p-ABA)₃·H₂O and Ln(p-ABA)₃·H₂O(p-ABA=p-aminobenzoic acid; Ln =Y or Er) co-doped silica samples were prepared. It was found that the characteristic emissions of Tb³⁺ in the silica samples increase with the addition of Y(p-ABA)₃·H₂O, while the reverse is true with the addition of Er(p-ABA)₃·H₂O. Compared with only Tb³⁺ complex doped silica sample, the photoacoustic intensity in the region of the ligand absorption decreases for Tb³⁺ and Y³⁺ complexes co-doped sample, and increases for Tb³⁺ and Er³⁺ complexes co-doped sample. The relative luminescence quantum yields and lifetime for the co-doped samples were determined, and the possible mechanism for the co-luminescence phenomena was interpreted from two aspects: radiative and nonradiative processes. Lanthanide complexes doped wet silica gels, which have undergone aging and drying at room temperature only, were also studied. The results indicate that p-ABA does not coordinate with the lanthanide ions in the silica gels without a suitable heat treatment. The co-luminescence effect found in this work will contribute the better design of new type of luminescence materials.

Preparation of Magnetic Fe2O3-TiO2 Nanocomposite and Its Photocatalytic Activity Under Visible Light Irradition

LI Xiu-Ying, WANG Jing-Yu, WANG Xiao-Yu, SU Dan, HAN Xi-Jiang*, DU Yun-Chen

2010, 31(4):  662-666. 

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The composite photocatalysts of Fe₂O₃-TiO₂ were prepared using FeCl₃ and Ti(C₄H₉O)₄ as precursors by sol-gel method. The photocatalysts were characterized by means of X-ray photoelectron spectroscopy(XPS), X-ray diffraction(XRD), scanning electron microscopy(SEM), and energy-dispersive X-ray spectroscopy(EDS), and nitrogen adsorption-desorption isotherms using the Brunauer-Emmett-Teller(BET) method. The results show that the composite consists of pure anatase TiO₂ and Fe₂O₃ with a diameter of about 15 nm. The photocatalytic activity of the Fe₂O₃-TiO₂ composite was confirmed through the photodegradation of methyl blue dye under visible light irradiation(λ>420 nm). The experimental results show that the composite photocatalysts have highly enhanced the photocatalytic efficiency in visible region when compared with each of the two pure semiconductor. The removal rate could reach the highest value under the molar fraction of Fe at 1.0 %. More importantly, the magnetic properties are measured using a vibrating sample magnetometer, and the results show that the Fe₂O₃-TiO₂ photocatalyst could be separated from the solution in magnetic field after reaction and then could be recycled.

On-chip Temperature Gradient Capillary Electrophoresis with Thermal Resistance Gradient Heating System for DNA Mutation Detection

XU Zhang-Run*, LI Na, ZHANG Hui-Dan, FAN Xiao-Feng, FANG Jin*

2010, 31(4):  667-671. 

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A simple and reliable on-chip spatial temperature gradient capillary electrophoresis was developed for DNA mutation detection using a thermal resistance gradient heating system. Polydimethylsiloxane(PDMS) slab with thermal resistance varying in gradient was made, and continuous temperature gradient was formed on slab surface using a single thermostated copper heater block owing to heat exchange influenced by varied thermal resistance. Different temperature gradients were produced by regulating the thickness of PDMS slab, and the temperature gradients were stable and uniform within 6 h. Utilizing the heating system, 209 bp DNA mutation standard samples were separated within a wide temperature range of 10 ℃ on a glass microchip with an assay time of 8.3 min. Effectiveness of the system was demonstrated by the successful detection of K-ras gene mutations in paraffin tissue sections from 3 colorectal cancer patients.

Amperometric Glucose Biosensor Based on Palladium Nanoparticles Combined Aligned Carbon Nanotubes Electrode

XU Ying1, ZHAO Kun2, ZHANG Xiao-Yan1, HE Pin-Gang1*, FANG Yu-Zhi1

2010, 31(4):  672-678. 

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Aligned carbon nanotubes(ACNTs) electrode was used as a new support to electrodeposit palladium nanoparticles(Pd nps), the resulting nano-composite showing its outstanding catalytic activity to hydrogen peroxide(H₂O₂). Herein the Pd(Ⅳ) ions were firstly covalently linked with ACNTs, and then were electrochemical reduced into Pd nanoparticles. After the glucose oxidase modification, such prepared electrode was employed as the enzyme electrode for glucose detection. The results show that these Pd nps have obviously enhanced the response sensitivity of the glucose biosensor in a short response time(<5 s) and at a low oxidation potential(<0.4 V) when detecting the H₂O₂ liberated in the enzymatic reaction between glucose oxidase and glucose.

Isolation and Purification of a New Shikimic Acid Derivative from Schisandra Chinensis and Its Content Assay

ZHU Hong-Yan, MENG Xiang-Ying*, BAO Yong-Li, YU Chu-Lei, WU Yin, LI Yu-Xin

2010, 31(4):  679-683. 

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A new shikimic acid derivative(1) was isolated from the ethanol extract of Schisandra chinensis(Turcz.) Baill. The structure of compound 1 was elucidated as n-butyl shikimate, on the basis of the 1D NMR, HMQC and HMBC spectroscopic techniques. A RP-HPLC method was performed in a extend C₁₈ column with a gradient elution mobile phase of acetonitrile-0.05%H₃PO₄ water solution at a flow rate of 1.0 mL/min, and the detection wavelength was 215 nm. A good linearity for n-butyl shikimate was obtained within the concentration range of 2—65 μg/mL(r=0.9999), and the recovery was 98.25% with RSD 1.55%. The method was simple, accurate with good repeatability.

Gene Expression Studies of Melamine-related Renal Toxicity Based on cDNA Microarray

SHI Mei, FAN Xue-Mei, LI Xue* , WANG Zheng, WANG Yi-Ming, LUO Guo-An*

2010, 31(4):  684-689. 

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Nowadays, microarray technology has been used in toxicogenomics more and more often. In this paper, we applied it into the renal toxicity research of melamine, which is an intermediate of resin in chemical industry. The experimental, through microarray and bioinformatics, was designed to find the differences between two cases in which the rats independently intervened by high and low doses melamine, and then to interpret the molecular mechanism of renal toxicity. The result indicated that the number of differentially expressed genes intervened by high dose of melamine were more than that by low dose of melamine. Besides, the differential expressed genes interfered by high dose melamine have been proved to have close connection with some important pathways as follow: valine, leucine and isoleucine degradation, citrate metabolism, glutathione metabolism, fatty acid metabolism, and the molecular function such as mental binding, lyase activity, ligase activity, symporter activity, glutathione transferase activity, monooxygenase activity. Our research show the toxicity in kidney intervened by melamine, and demonstrated the special advantage of microarray technology in toxicogenomics.

Determination of Phthalate Esters in Commercial Milk Samples Using PA6 Nanofibers Mat-based Solid-phase Extraction Coupled with Liquid Chromatography

YIN Xue-Yan1, XU Qian1,2*, WU Shu-Yan1, WANG Min1, GU Zhong-Ze2

2010, 31(4):  690-695. 

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A new method for simultaneous determnation of six phthalate esters in commercial milk was deve-loped by the combination of latest proposed PA6 nanofibers mat-based solid-phase extraction with high-perfor-mance liquid chromatography-ultraviolet detector(HPLC-UV). Conditions for obtaining optimum extraction efficiency such as extraction solvents and its volume, extraction time, eluant and its volume, amount of adsorbent, pH, flow rate of sample were investigated and optimized in detail. Under optimized conditions, the detection limits found for dimethyl phthalate(DMP), diethyl phthalate(DEP), butylbenzyl phthalate(BBP), dibutyl phthalate(DBP), diethyl hexylphthalate(DEHP) and dioctyl phthalate(DOP) were 0.02, 0.01, 0.05, 0.05, 0.10 and 0.25 ng/mL, respectively. The proposed method was applied to the analysis different brands and packaging of milk samples. PAEs in commercial milk samples can be completely extracted by 2.5 mg PA6 nanofiber mat. The satisfactory spiked recoveries were obtained in the range of 93.40%—104.83% with relative standard deviation(RSD) of below 5.82% were achieved. The main advantages of the method are low detection limits, high sensitivity and selectivity and the results are accurate and reliable, reproducible.

Covalently and Non-covalently Modification of Multi-walled Carbon Nanotubes with Tetra-(4-hydrazidephenyl)porphyrin and Metalloporphyrin

ZHAO Hong-Bin*, XU Lan-Lan, WANG Hong-Ke, ZHANG Hui, WANG Wu-Lin, ...

2010, 31(4):  696-702. 

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Tetra-(4-hydrazidephenyl)porphyrin and its Cu, Zn complexes were synthesized with new techniques. The covalent porphyrins-functionalized MWNTs were gained by amidation reaction between the oxidized multi-walled carbon nanotubes(MWNTs) and the hydrazide porphyrins. The non-covalent porphyrins-functionalized MWNTs were obtained through π-π pileup with tetra-(4-hydrazidephenyl)porphyrin and MWNTs. The structures of the resultant products were characterized by FTIR. Strong electronic effects between porphyrins and MWNTs were found from UV-Vis absorption and fluorescence spectroscopy. Moreover, non-covalent composites provide a higher emission quenching compared with covalent composites.

Three-photon Absorption and Upconversion Fluorescence of Bis-, Quadri-, Octu-branched Symmetrical Oxadiazole Derivatives

QIAN Ying*, ZHU Xiao-Qin, JI Yan, HUANG Wei, Lü Chang-Gui, CUI Yi-Ping

2010, 31(4):  703-707. 

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The three-photon absorption and the three-photon-excited fluorescence spectra of three symmetrical oxadiazole derivatives, 4-[N,N-bis(4-{4-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]styryl}phenyl)amino]benzaldehyde(Bis-oxa), 2,5-bis(4-{2-N,N-bis[4-(2-{4-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]-phenyl}-vinyl)phenyl]aminostyryl}phenyl)-1,3,4-oxadiazole(Quadri-oxa) and 2,5-bis(4-{2-N,N-bis[4-(2-{3,5-di-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]phenyl}-1-ethenyl-)phenyl]aminostyryl}phenyl)-1,3,4-oxadiazole(Octu-oxa) were measured by nonlinear transmission method using a femtosecond Ti∶sapphire laser. Their three-photon absorption coefficients of 1260 nm were 5.0×10^-5, 10.0×10^-5 and 10.0×10^-5 cm³/GW², respectively. Pumped by a femtosecond laser at 1260 nm, strong upconversion fluorescence with the central wavelength at 533 nm(Bis-oxa), 544 nm(Quadri-oxa)and 551 nm(Octu-oxa) in the solution of CH₂Cl₂ have been observed. A detailed spectroscopic study of these chromophores, including absorption, fluorescence emission, fluorescence lifetime, multiphoton excited fluorescence and 3PA coefficient were measured. The multibranched symmetrical oxadiazole derivatives display large three-photon absorption and strong upconversion fluorescence properties.

Synthesis, Crystal Structure and Bioactivities of 2-Cyanoacrylates Containing 5-Ethoxy-1,3,4-thiadiazol-2-methylamine Moiety

WANG Ting-Ting, BING Gui-Fang, ZHANG Xin, QIN Zhen-Fang, YU Hai-Bo, QIN Xue, ...

2010, 31(4):  708-713. 

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Herbicidal activity of cyanoacrylates has been the subject of intense interest for the past decades. A detailed study revealed that cyanoacrylates are inhibitors of photosystemⅡ(PSⅡ) electron transportation. In this paper, a series of novel 2-cyanoacrylates containing 5-ethoxy-1,3,4-thiadiazol-2-methylamine moiety were synthesized from 5-ethoxy-1,3,4-thiadiazol-2-methanamine and 2-cyanoacrylates in refluxing ethanol. Their structures were confirmed by ¹H NMR and elemental analysis. Biological activity tests showed that some compounds exhibited good herbicidal activities and excellent selectivity against dicotyledonous weeds such as rape and amaranth pigweed. Compound 6j show the highest herbicidal activity at the dose of 600 g/ha with 100% and 95.2% inhibition activity against rape and amaranth pigweed in postemergency treatment. It show the same herbicidal level as the contrast compound B. A appropriate size group at the 3-position of acrylates is essential for high herbicidal activity. 2-Cyanoacrylates containing 5-ethoxy-1,3,4-thiadiazol-2-methylamine moiety have the research potency, further study is underway.

Imidazolium-based Fluorescent Chemosensor for Highly Selective Recognition of Dihydrogen Phosphate

SU Dong-Dong, NIU Hao-Tao, WANG Ying, HE Jia-Qi*, CHENG Jin-Pei

2010, 31(4):  714-717. 

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Due to the fundamental roles that anions play in a wide range of chemical and biological processes, numerous efforts have been devoted to the design of receptors capable of selectively binding and sensing anions. The development of selective receptors for phosphate anions is of particular interest because they play vital roles in a wide range of life processes, such as energy storage, signal transduction and gene construction. Herein, a new fluorescent chemosensor bearing two imidazolium groups as well as two anthracene groups were designed and synthesized. The anion recognition properties of the compound 1 were studied by the UV-Vis and fluorescent spectra in CH₃CN. The results show that this chemosensor display a highly selective fluorescence quenching effect and a unique excimer peak only with H₂PO₄^-. The fluorescence quenching effect can be ascribed to a photo-induced electron transfer(PET), which can be used to discriminate H₂PO₄^- from the other anions tested. ¹H NMR analysis revealed that both the imidazolium 2-CH and the amide NH were involved in the hydrogen bonding interactions with the anions.

Reduction of the Aromatic Nitro Group in Peptide by Ammonium Formate Catalytic Transfer Hydrogenation——An Indirect Introduction of p-Aminophenylalanine into Peptide Chain

GAO Yong-Qing, ZHOU Ning, Lü Yu-Jian, SHI Wei-Guo, CHENG Mao-Sheng, ...

2010, 31(4):  718-722. 

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The p-aminophenylalanine was a useful functional amino acid in the design of peptide drugs, and it was usually prepared by the reduction of p-nitrophenylalanine. Ammonium formate catalytic transfer hydrogenation(AF-CTH) was confirmed feasible in transforming the aromatic nitro group into the amino group in a dipeptide, and the orthogonal protection for p-aminophenylalanine in traditional route could be avoided in this method. Therefore, we wondered if this method could be widely used for the reduction of p-nitrophenylalanine residue in various peptides, such as the MSH(tetrapeptide), LHRH(decapeptide) and dynorphin(heptadecapeptide) analogues. The reduction processes were monitored by HPLC and the results showed that all sequences could be smoothly transformed into the desired products, except the LHRH analogue containing p-chlorophenylalanine due to the dechlorination. It suggested that AF-CTH was an effective method for the reduction of the nitro group in a peptide. In addition, it was found that the reduction rate of the nitro group was slower in longer peptide and not obviously correlative to its site in peptide.

Catalysis of Metallo-deuteroporphyrins for Cyclohexane Oxidation with Air

ZHOU Wei-You, HU Bing-Cheng*, XU Shi-Chao, SUN Cheng-Guo, LIU Zu-Liang

2010, 31(4):  723-726. 

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The efficient and selective oxidation of hydrocarbon catalyzed by metalloporphyrins has attracted much attention from the organic and industrial chemists. During the last decades of years, a huge amount of work has shown that substituted metalloporphyrins are efficient catalysts for the oxidation of hydrocarbons at unprecedented rates under very mild conditions. However, nearly all of the metalloporphyrins used as oxidation catalysts were based on the system of synthetic meso-tetraphenylporphyrin(TPP). The high accessibility of deuteroporphyrin together with its excellent stability and close relationship to the naturally occurring heme make it an ideal compound to mimic enzymatic systems based on heme. Therefore, to investigate the catalytic activity of the deuteroporphyrins complex and search more efficient biomimetic catalysts for hydrocarbon oxidation under mild conditions, the metallo-deuteroporphyrin dimethyl esters[M(DPDME)] were used as the catalysts for cyclohexane oxidation by air without any coreductant or solvent. The results indicated that the metallo-deuteroporphyrins could smoothly catalyze the oxidation of cyclohexane under the selected conditions; and they exhibited markedly higher catalytic activity than simple metallo-tetraphenylporphyrins. The effect of central metals was discussed.

Selective α-Bromination of Functionalized Ketene Dithioacetals

BEKTURHUM Bahargul, WANG Mang*, HAN Feng, LIU Qun

2010, 31(4):  727-730. 

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Functionalized ketene dithioacetals are important intermediates in organic synthesis. α-Functiona-lization reactions based on them provide potential precursors for the construction of usefully carbo- and heterocyclic compounds. In this paper, a versatile α-bromination of functionalized ketene dithioacetals was developed. In the presence of H₂O, the reactions of functionalized ketene dithioacetals(1) with CuBr₂ in THF at room temperature gave various α-bromo ketene dithioacetals(2) in excellent yields with high regioselectivities. The mechanism of this α-bromination is proposed to undergo an addition of bromine formed in situ to compound 1 and sequontial elimination of the α-proton. The simplicity of execution, mild conditions, inexpensive, easily usable brominating agent and high yields, make this synthetic method attractive for practical applications.

Indole Alkaloids from the Leaves of Rauvolfia yunnanensis

GENG Chang-An, LIU Xi-Kui*

2010, 31(4):  731-735. 

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Rauvolfia yunnanensis Tsiang are commonly used as a folklore herb to treat hypertension, snake bites, and insanity in the southwest of China, and an important industrial raw material of reserpine and vertical. But the wild resources of it reduced gradually in recent years, thus we have introduced and cultivated it to the arid-hot valley region of Yunnan Province, China, and investigated the chemical constituents variety of it for the sustainable utilization. The dried leaves powder(8.0 kg) of R. yunnanensis was extracted with 95%(volume fraction) EtOH(40 L×5 , 8 h each), and led to the isolation of eleven indole alkaloids by column chromatography(silica, alumina and Sephadex LH-20 gel) methods. Their structures were identified as caberine(1), 19-ethoxyl-1-demethyl-Δ¹-17-acetylajmaline(2), vellosimine(3), β-yohimbine(4), yohimbine(5), vinorine(6), picrinine(7), nareline(8), akuammicine(9), strictamine(10), reserpine(11) by spectral analysis(UV, IR, MS and 1D, 2D NMR), respectively. Among them, compound 2 was a new indole alkaloids, compounds 1, 8 and 9 were firstly isolated from this plant.

Proteomic Analysis of Fear Memory Related Proteins in Mice

ZHENG Jun-Fang, LIU Hua, XIONG Ying, WANG Xiao-Zhu, HE Jun-Qi*

2010, 31(4):  736-741. 

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To investigate proteins related with fear and emotional memory, hippocampal proteins from CD1 and C57BL/6J mice after fear conditioning experiment were extracted and subjected to 2D gel electrophoresis. Protein quantification was analyzed and the differentially expressed spots were identified using mass spectrometry and MASCOT database searching. Hippocampal proteins from CD1 and C57BL/6J mice after fear conditioning experiment were significantly different. Twenty-nine proteins(Thirty-one spots) are closely related with fear memory formation. Expression levels of 7 spots downregulated significantly; expression levels of 24 spots increased significantly. These identified proteins could be devided into six categories according to their functions: (1) energy metabolism and mitochondrion function; (2) neurogenesis; (3) signal transduction; (4) cytoskeleton; (5) amino acid metabolism and protein degradation; (6) chaperone. These proteins improved insights into the fear mechanism and provided new targets for the study and treatment of cognitive diseases.

Homology Model and Functional Prediction of the Three Dimensional Structure of HBsAg of Hepatitis Virus

ZHOU Xiao-Ping, ZHANG Mu-Xin, WANG Guang-Shu, YANG Xiao-Hong*

2010, 31(4):  742-745. 

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When hepatitis B virus(HBV) conduct the planting process into normal liver cell, hepatitis B virus surface antigen(HBsAg) plays an important role during this process, but its crystal structure information has not been reported in the Protein Data Bank. In order to make further research about the structure and function of HBsAg, we constructed the three dimensional structure of HBsAg Pres12 using biology information homology model methods, and explored the mechanism as an important antiviral target at the molecular level by molecular simulation method. The results showed that the three dimensional structure of HBsAg consist the conformational Pres1 and the linear Pres2, three α-helixes and some loop region consist the whole structure, at the same time, some amino residues in the N-terminal of Pres1 make a cleft which forms the potential active site domain. The electrostatic analysis confirmed that, the N-terminal potential active site possess bigger electrostatic distribution and may have the ability to interact with recipient cell protein, this study will provide useful information for the design of anti-HBV drug molecules.

Effect of 17-β-Estradiol on Hypoxia-reoxygenation-induced NF-κB Activity, ICAM-1 and VCAM-1 Expression in Cardiac Myocytes

HUO Hong-Liang, AN Shang-Yu, ZHONG Shi-Gang, ZENG Qing-Hua*

2010, 31(4):  746-750. 

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Transcription factor(NF)-κB plays an important role during hypoxia-reoxygenation in cardiac myocytes. In previous studies, it has been proved that NF-κB can bind to the specific sequences located in the promoters of ICAM-1 and VCAM-1, ediate the expression of tow adhesion molecules, and cause the cell inflammatory response and apoptosis. In order to analyze the anti-inflammation function of 17-β-estradiol during hypoxia-reoxygenation, we established the hypoxia-reoxygenation model in cardiac myocytes which were isolated from neonatal rat. And then, we detected the effect of 17-β-estradiol on activation of NF-κB p65 and studied the estrogen on how to adjust the level of ICAM-1 and VCAM-1 by Flow Cytometry, Western Blot, RT-PCR and Elisa technology. The results show that the NF-κB pathway is activated during hypoxia-reoxygenation, and 17-β-estradiol inhibits this activation significantly. 17-β-Estradiol also inhibits the expression of ICAM-1 and VCAM-1 by both NF-κB-dependent and NF-κB-independent pathway. Taken together, all results suggested that anti-inflammatory effect of 17-β-estradiol during myocardial hypoxia-reoxygenation is achieved through multichannels.

Experimental Study of the Effects of Ammonium Nitrate on SO₂ Gas-particle Transfer on the Surface of Atmospheric Aerosols

LIN Li, KONG Ling-Dong*, CHEN Jian-Min

2010, 31(4):  751-755. 

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Heterogeneous oxidation of gaseous SO₂ on NH₄NO₃-containing hematite compared to other NH₄NO₃-containing oxides(MgO, Al₂O₃, CaO, SiO₂) were first studied using an in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS). Obvious sulfate formation can be seen from the infrared spectrum of NH₄NO₃-containing oxides, and the catalytic activity of hematite is much higher compared to other oxides. Using BET area as the reactive surface area, the hematite sample containing 6%(mass fraction) of NH₄NO₃ presents the highest γ_BET value(2.42×10^-9), which is about 1.8 times larger than that of hematite. No formation of sulfate is observed on the pure NH₄NO₃. The results show that appropriate NH₄NO₃ increases the sulfate formation while more NH₄NO₃ impedes. Mechanism is discussed.

Effect of SDBS on Electron Transfer at the NB/H₂O Interface by Thin Layer Method

DONG Cun-Wu, LI Li, ZHAO Xue-Ping, LU Xiao-Quan, LIU Xiu-Hui*

2010, 31(4):  756-760. 

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The effect of an adsorbed anionic surfactant sodium dodecyl benzene sulfonate(SDBS) on electron transfer(ET) reaction between ferricyanide aqueous solution and decamethylferrocene(DMFc) located on the adjacent organic phase was investigated by thin layer method. The experimental results showed that the adsorption of SDBS at the interface resulted in a decay in the cathodic plateau current of bimolecular reaction across immiscible electrolyte solutions(ITIES) between DMFc in the organic phase and Fe(CN)₆^3- in the aqueous phase. However, the rate constant of the electron transfer(k_et) reaction above mentioned increased monotonically as the SDBS concentrations increased from 0 to 200 μmol/L. The reason is caused by formation patches spontaneously of SDBS on the interface and it will then influence the structure of electrical double layer on the interface, and shorten the distance between the redox centers. The surface adsorb of SDBS follow Langmuir isotherm.

Comparison of Catalytic Performance and Stability for Pt Catalysts Supported on Different Materials in Chiral Hydrogenation of Ethyl Pyruvate

WANG Hong-Na, SHEN Ya-Li, LI Bo, LI Xiao-Hong*, WU Peng

2010, 31(4):  761-765. 

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5.0%(mass fraction) Pt catalysts supported on periodic mesoporous resols(FDU-14) and ordered mesoporous carbon materials(CMK-3) were prepared using a wet impregnation method, respectively. The ca-talytic performances of Pt/FDU-14 and Pt/CMK-3 catalysts in the asymmetric hydrogenation of ethyl pyruvate were compared with the commercial Pt/Al₂O₃ catalyst. Although the commercial Pt/Al₂O₃ catalyst affords the highest initial activity and enantioselectivity, the Pt/FDU-14 and Pt/CMK-3 catalysts are superior to Pt/Al₂O₃ in immobilization of platinum under the same conditions. Based on the chemical nature of different supports, the difference in the catalytic performance and stability of three supported Pt catalysts was interpreted for the enantioselective hydrogenation of ethyl pyruvate.

Theory Study on Ambipolar Carrier Transport Properties of Bis(o-diiminobenzosemiquinonate) Nickel(Ⅱ) Complex

TANG Xiao-Dan, GAO Hong-Ze, Geng Yun, LIAO Yi*, SU Zhong-Min*

2010, 31(4):  766-771. 

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By means of the density functional theory level with UB3LYP function, the ground state and ionic structures of the complex bis(o-diiminobenzosemiquinonate) nickel(Ⅱ)(PHDANI) were optimized and the diradical character of PHDANI was successfully simulated. The hole and the electron reorganization energies were evaluated directly from the adiabatic potential-energy surface and the transfer integrals were calculated using direct method. Then, the charge carrier transport properties of PHDANI were investigated based on Marcus electron transfer theory. The results indicate that the hole and the electron mobilities of PHDANI, which are in the same order of magnitude, are 0.253 and 0.135 cm²·V^-1·s^-1, respectively. In theory, the transport properties of PHDANI are quite well as an ambipolar carrier transport material.

Theoretical Studies on the Structures and Stabilities of [MAl₅]⁺(M=Si,Ge,Sn,Pb)

HE Hai-Peng, CUI Zhong-Hua, DING Yi-Hong*

2010, 31(4):  772-776. 

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By means of the B3LYP and CCSD(T)(single-point) methods, we investigated the isomeric structures and thermodynamic stabilities of four hexa-atomic systems [MAl₅]⁺(M=Si,Ge,Sn,Pb). The results show that although bearing the same 18-valence electrons as [CAl₅]⁺, all the [MAl₅]⁺(M=Si, Ge, Sn, Pb) systems do not have a planar pentacoordinate M isomer. Instead, the global structure is a C_s-symmetrized butterfly isomer Int1. This can be rationalized that the bulkier central atom M(Si, Ge, Sn, Pb) than C has significantly destructed the stability of the planar pentacoordinate structure of [MAl₅]⁺.

Theoretical Studies on Photophysical Properties of the 2-Phenylpyridine Iridium(Ⅲ) Complex and Its Derivatives

WU Qing-Xiu, SHI Li-Li, ZHAO Shan-Shan,WU Shui-Xing, LIAO Yi*, SU Zhong-Min

2010, 31(4):  777-781. 

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A series of iridium(Ⅲ) complexes(C^N)₂Ir(acac) [C^N=ppy, 1; C^N=npy, 2; C^N=pq, 3; C^N=bzq, 4; ppy=2-phenylpyridine, npy=2-naphthalene-1-ylpyridine, pq= 2-phenylquinoline, bzq=benzoquinoline, acac=acetoylacetonate] was investigated theoretically to probe their electronic structures and spectroscopic properties. Their ground and excited state geometries were fully optimized at B3PW91/LANL2DZ and UB3PW91/LANL2DZ levels, respectively. Then, by means of the TD-DFT method, the absorption and emission spectra of complexes 1—4 were calculated on the basis of the optimized ground and excited states geometries, respectively. The calculated results show that the position of phenyl group on the 2-phenylpyridine will decrease the energy gap to different extent, while the absorption and emission spectra of complexes 2, 3 and 4 are bathochromic shifted compared with complex 1. In addition, the addition of phenyl group on the pyridine significantly influences the absorption spectra. And the low lying absorption energies are in the order 1<2<4<3, but the emission spectra are in the order 1<4<3<2. The repulsion between the C6—H and C9—H of the complex 2 reduces the π-conjugation effect, which greatly affects its geometry rela-xation between the ground and excited states, which results in the large Stokes shift.

Application of the Electrostatic and Steric-hindrance Model to Analysis of Transmembrane Potential Across Nanofiltration Membranes

FANG Yan-Yan, TU Cong-Hui, WANG Xiao-Lin*

2010, 31(4):  782-789. 

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The electrostatic and steric-hindrance model was employed to analysis transmembrane potential arising across nanofiltration membranes theoretically. The effects of solution volume flux, feed concentration, diffusion coefficient ratio of co-ion to counterion, membrane pore radius and membrane volume charge density on transmembran potential including membrane potential and convective potential across nanofiltration membranes in KCl(1-1 electrolyte) and MgCl₂(2-1 electrolyte) were investigated. The results showed that the linearity of transmembrane potential of KCl and MgCl₂ increased with increase of solution volume flux. Transmembrane potential of the two electrolytes decreased while feed concentration and pore radius increased. Due to the complex mechanism, the influence of diffusion coefficient ratio of co-ion to counterion on potentials behaved differently in different concentration range and electrolyte species. Compared with MgCl₂, the curves of transmembrane potential of KCl as a function of membrane volume charge density exhibited evidently symmetry on the origin, but transmembrane potential zero point of MgCl₂ appeared when membrane volume charge density was negative.

Preparation of Solid-state Multicolor Electrochromic Devices Based on Conducting Polymers

CHEN Li-Xian, WENG Shao-Huang, ZHOU Jian-Zhang*, LIN Zhong-Hua

2010, 31(4):  790-795. 

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Multicolor solid-state electrochromic devices(ECD) based on conductive polymer[poly(3-methylthiophene)(P3MeT) and polyaniline(PANI)] were constructed in two kinds of configuration: lateral and vertical. The electrochromic performance of the laterally configured ECD was characterized by in-situ UV-Vis spectroscopy. P3MeT ECD shows blue-red reversible changes, and PANI-ECD shows darkgreen-yellowgreen reversible changes. The laterally configured P3MeT-PANI-ECD which employed both PANI and P3MeT as electrochromic layer exhibits darkgreen-yellowgreen-blue-red multicolor changes. ECD miniaturized by laser engraving also exhibits multicolor changes. Introducing CeO₂-TiO₂ as the complementary electrode, the vertically configured P3MeT-PANI-ECD can show four colors freely.

Effect of TiF₃ on the Dehydrogenation of LiAlH₄

LIU Shu-Sheng, SUN Li-Xian, SONG Li-Fang, JIANG Chun-Hong, ZHANG Jian, ...

2010, 31(4):  796-799. 

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The dehydrogenation performances of as-received, ball-milled and different amounts of TiF₃ doped LiAlH₄ were investigated by X-ray diffraction(XRD), Fourier transformed infrared spectrometer(FTIR) and thermogravimetry(TG) measurements. It was found that LiAlH₄ decomposes a little during ball milling in the presence of TiF₃. TiF₃ has dramatically catalyzed the dehydrogenation of LiAlH₄. With increasing amount of TiF₃, the initial temperature of dehydrogenation decreases to some extent, but it sacrifices the dehydrogenation amount at great cost. 2%(molar fraction) TiF₃-doped LiAlH₄ begins to release H₂ at 80 ℃, 70 ℃ lower than as-received LiAlH₄, and can release as much as 6.6%(mass fraction) H₂.

Preparation, Characterization of PAMAM Dendrimers-coated Liposomes and Evaluation for Ophthalmic Drug Delivery

LIU Yi, SUN Kao-Xiang*, YAO Wen-Jun, LIANG Na, MU Hong-Jie, LIANG Rong-Cai, YAO

2010, 31(4):  800-805. 

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PAMAM dendrimers-coated liposomes encapsulated puerarin were prepared and the particle size, zeta potential and drug release property were investigated. Fluorescein isothiocyanate (FITC)-labeled PAMAM dendrimers were prepared to study adsorption rate. Transmission electron microscope and laser confocal scanning microscopy were used to explore the morphology and structure of PAMAM-coated liposomes. The in vitro transcorneal penetration, precorneal residence time, residual amount of puerarin within corneal of PAMAM coated liposomes were evaluated. The results showed that the size of the coated liposomes was little larger than that of the uncoated liposome but no significantly difference and the zeta potential became positive from negative and increased along with ratio of PAMAM. The cumulative release of PAMAM coated liposomes was similar to that of uncoatd liposome with slower release property. The PAMAM coated liposomes were nonirritant and could remarkably improve permeability of puerarin transcornea, prolong corneal residence time, increase residual amount of PUE within cornea, compared with uncoated liposome and PUE drop solution(P＜0.01). The PAMAM coated liposomes is promising as a novel ophthalmic drug delivery system.

Crystalline Morphologies of Poly(D-lactic acid) Thin Films

LI Hai-Dong, LIN Yu-Han, NIE Wei, DENG Chao, CHEN Xue-Si, JI Xiang-Ling*

2010, 31(4):  806-810. 

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Crystalline morphologies of spin-coated poly(D-lactic acid)(PDLA) thin films under different conditions were investigated by atomic force microscopy (AFM) technique. The morphology evolution of the PDLA crystalline was tuned by changing concentration of the polymer solution, the crystallization time, solvent types and substrates. Different crystalline morphologies, such as short rod, fiber bundle and spherical structure were obtained. Meanwhile, the possible mechanism for crystalline morphology evolution was proposed.

Electrospinning of Soy Protein Isolate/Poly(vinyl alcohol)

ZHAO Liang, TANG Gong-Wen, SU Jun-Feng, HAO Xin, ZHANG Yuan, SHI Chen-Lu, JIANG

2010, 31(4):  811-814. 

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Electrospinning of soy protein isolate(SPI) in the presence of poly(vinyl alcohol)(PVA) was investigated in order to broaden applications of SPI. The effect of properties of SPI/PVA solutions and the glycerol addition on the morphology of electrospun fibers were discussed. Characterization and mechanical properties of electrospun SPI/PVA membranes were also analyzed. The results show that introduction of glyce-rol can improve the electrospinability of SPI/PVA. The tensile strength of electrospun SPI/PVA membranes decrease from (5.17±0.62) MPa to (1.67±0.21) MPa and the elongation show an increase tendency with increasing the amount of glycerol.

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Crystallization of H-Shaped (PS)₂PEG(PS)₂ Block Copolymer During Spin Coating

PAN Ying-Ying, ZHANG Ji-Dong, SHI Tong-Fei*, AN Li-Jia

2010, 31(4):  815-820. 

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The morphologies of H-shaped (PS₇)₂PEG₂₂₇(PS₇)₂ block copolymer films spin coated onto silicon wafers from different solutions were investigated by means of atomic force microscopy(AFM) and grazing incidence X-ray diffraction. We further compared the crystallization of H-shaped block copolymer with that of ply(ethylene oxide)(PEG) homopolymer. The presence of PS block changed the interaction of polymer and substrate. When solvent was tetrahydrofuran, the copolymer dewetted and crystallized after spin coating when the concentration of solution was 0.1% and 0.25%. As the concentration increased to 0.5%, dewetting was suppressed and two-dimensional spherulites appeared. If toluene was used as solvent, micelles were formed in the solution due to the differences between solubility of PEG and PS block, which changed the final film morphologies. Dendritic crystals containing edge-on and flat-on crystals appeared from the 0.1% solution. More compact crystals appeared while the concentration increased, and large square lamellae was observed after spin-coating of 0.5% solution.

Articles

Corneal Substitutes of Protein-loaded Collagen/Polyzwitterion IPN

LIANG Shuang, YANG Jian-Hai, LIU Gui-Pei, LIU Wen-Guang*

2010, 31(4):  821-828. 

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Collagen/polyzwitterion IPN based corneal substitutes were fabricated by crosslinking porcine type I atelocollagen and N-[3-(methacryloylamino)propyl]-N,N-dimethyl-N-(3-sulfopropyl) ammonium hydroxide (MPDSAH) with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide/N-hydroxysuccinimide and poly(ethylene glycol) diacrylate (PEGDA), respectively. The white light transmission and refractive indices of IPN corneal susbtitutes were similar to those of natural human cornea. IPN hydrogels had superior mechanical properties and collagenase resistance compared to pristine collagen hydrogels. Human corneal epithelia grew well on the surface of IPN hydrogel. Bovine serum albumin(BSA) and nerve growth factor(NGF) were efficiently encapsulated in corneal substitute by freeze-drying and re-swelling, and drug-embedded xerogels could be stored in dry state, avoiding the denaturation and leakage of active factors in wet state. It is expected that the completely shape-recovered corneal subsitutes after re-swelling can be implanted into diseased site. BSA and NGF were found to release from IPN hydrogel in a sustainable manner. NGF-loaded composite corneal substitute shows promise in promoting the regeneration of corneal tissue as well as nerve.

Frictional Behavior of Poly(2-acrylamido-2-methylpropanesulfonic acid) Hydrogel-gss SystemInfluence of Compressive Modulus

DU Miao*, ZHANG Yan, ZHENG Qiang

2010, 31(4):  829-833. 

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The frictional behavior of poly( 2-acrylamido-2-methylpropanesulfonic acid )( PAMPS ) hydrogel sliding against glass plate in water were studied over a wide sliding velocity region. It reveals that the frictional stress(f) increases with increase sliding velocity(v) at high velocity region, and f∝v prevails, which is considered as the hydrodynamic lubrication. However, at small v region, f∝v failed and f decreases slightly as v increase, which does not obey the hydrodynamic lubrication mechanism. The decrease of f with v in small v region does not arise from the stress relaxation of PAMPS hydrogel during the measurement but the shearing thinning of PAMPS hydrogel surface network and the mixed lubrication. PAMPS gel with high compressive modulus(E) exhibits high f than that of hydrogel with small E at slow v region, which is not coincide with the model′s expectation. At the same time, PAMPS hydrogel with small E is observed to be easy to form hydrodynamic lubrication than that with large E. This is believed to be related to the excellent deforming ability of PAMPS hydrogel with small E.

Stress-sensitive Optical Properties of Polymer-immobilized Crystalline Colloidal Array Films

HUANG Xue-Guang, YANG Zheng-Wen, SUN Jing-Bo, SUN Li, LI Bo, ZHOU Ji*

2010, 31(4):  834-838. 

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Polymer-immobilized crystalline colloidal array(PCCA) films composed of polyacrylamide were fabricated by photoinitiated polymerization based on crystalline colloidal arrays composed of monodisperse polystyrene(PS) particles. The stress-sensitive optical property of PCCA film was investigated by micro-region reflectivity spectrometer under a series of loads. It was revealed that an acute peak can be found in the reflectivity spectrum of PCCA film, which was corresponding to the photonic bandgap of the film, and the midgap wavelength shifted approximately linearly and reversibly with load.