Category: Chemistry

Chemistry Complex Crystal

Synthesis and characterization of Fire retarded poly (DAMT -co-acrylonitrile)

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Abstract In this paper diethoxy-acrylamide methoxyl thiophosphate (DAMT) was synthesized with the reaction N-hydroxymethyl acrylamide and O, O-diethyl phosphorochloridothioate catalyzed by cuprous chloride in presence of triethylamine, and the flame retarded poly (DAMT-co-acrylonitrile) was obtained though free-radically copolymerized process. The properties of copolymer were estimated by Limiting Oxygen Index (LOI) values and thermogravimetric analysis (TGA). The results showed that the LOI value of copolymer with 20 wt% percentage of DAMT coule reach 27vol%.
Keywords: Diethoxy-acrylamide methoxyl thiophosphate, Polyacrylonitrile, Flame retardants, Thermal analysis, Limiting Oxygen Index

1 INTRODUCTION
Polyacrylonitrile (PAN) is widely used in many aspects because it is easily processed into products of various shape with well flexibility and retention at break to meet the requirements of versatile and advanced applications. However, the combustion of PAN is very easy when it is ignited, which makes it difficult to be used in some ways. Thus, the flame retardant PAN is required …

Chemistry Complex Crystal

De Novo drug design of anti-cancer drug imatinib’s analogues

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Abstract Based ON The Crystal Structure of of Imatinib and tyrosine kinase Complex (the PDB ID: 2HYY)., The Active Structure and pharmacophores of Imatinib, and The Interaction BETWEEN Imatinib and The Active Site of tyrosine kinase have have been Explored It WAS found that The methylpiperazin Group In imatinib bound to the active site of tyrosine kinase weaker than other substructure, and there are no important pharmacophores, so this part structure of imatinib can be rebuilt. Further molecular design of anti-cancer drug imatinib’s analogues was carried out by De Novo Drug Design Method, 199 molecules were obtained at first, and 10 molecules with high score were screened by docking software, this research results shows that imatinib ‘s analogues with potential for effective tyrosine kinase inhibitors.
KeyWords anti-cancer drug; imatinib; analogue; De Novo drug design

Initio Molecular Design of Antitumor Drugs Imatinib Derivatives

Abstract In this paper, the structure of tyrosine …

Chemistry

Electrostatic self assembly and characterization of ultra thin films of a secondary diazo dye

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  1. Dey, S.A. Hussain, D. Bhattacharjee
    (Department of Physics, Tripura University, Suryamaninagar-799130, India)AbstractIn this communication characterization of Electrostatic Layer by Layer (ELBL) Self Assembled films of secondary diazo dye Congo Red (CR) by alternate adsorption of Poly (allyl amine hydrochloride) (PAH) and CR is reported. The UV-Vis absorption spectra and second derivative analysis of ELBL films revealed the formation of J aggregate of CR molecules in the films. The film growth without any material loss, during subsequent deposition was evident from the Layer effect study of the ELBL PAH-CR films. About 10 minutes of time was required to complete the interaction between CR and PAH molecule in a single bi-layer of ELBL film. Theoretical correlation of the experimental adsorption kinetics data for PAH-CR ELBL films was found to follow second order adsorption kinetic equation. The pH of solution was observed to influence the adsorption process of CR in the
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Chemistry

Synthesis and photo-physical properties of substituted 2-(2-Hydroxyphenyl) benzimidazoles

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Lei Yingjie, Shen Hongqin, Zhang Youlai, Ouyang Jie
(School of Chemistry & Chem. Engineering，Tianjin University of Technology，Tianjin 300191)

Abstract A convenient method to synthesize 2-(2-hydroxyphenyl) benzimidazole with substituent(s) X (X=H, NH2, SO3H, CH2OH, ArN=N, mono-bromide and di-bromide ) via the reaction of substituted salicylaldehyde and o-phenylenediamine in the presence of manganese (Ⅲ) acetate was reported. The corresponding photo-physical properties were characterized by ultraviolet absorption and fluorescence spectra in methanol. Meanwhile, the fluorescent characteristics of these compounds were investigated on the basis of excited-state intramolecular proton transfer mechanism. Stokes’ shift and quantum yield were also derived.
Keywords Benzimidazole derivatives; Synthesis; Photo-physical properties

1. INTRODUCTION
Due to the intense emission property via excited-state intramolecular proton transfer (ESIPT), 2-(2-hydroxyphenyl) benzimidazole and its derivatives become a series of important fluorescent compounds, which are useful as a new kind of fluorescent probes[1-2] as well as for the …

Chemistry

Study on color reaction of 2-(2-quinolylazo)-5-dimethylaminoanline with palladium and its application

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Hu Qun 1, Hu Lin 2，Wang Jian 1，Wei Yuling 1 , Chen Yongkuan 1
(1 Yunnan Academy of Tobacco Science, Kunming 650106; 2Life science school,Yunnan University, Kunming 650091,  China)

Abstrasct A new chromogenic reagent, 2-(2-quinolylazo)-5-dimethylaminoaniline (QADMAA) was synthesized. A sensitive, selective and rapid method for the determination of palladium based on the rapid reaction of palladium(II) with QADMAA was developed. In the presence of 0.5-2.5 mol/L of hydrochloric acid solution and cetyl trimethylammonium bromide (CTMAB) medium, QADMAA reacts with palladium to form a violet complex of a molar ratio 1:2 (palladium to QADMAA). The molar absorptivity of the chelate is 1.35×105 L.mol-1.cm-1 at 600 nm. Beer’s law is obeyed in the range of 0.01~ 0.6 m g/ml. The relative standard deviation for eleven replicate sample of 0.2 m g/ml level is 1.02 %. This method had been applied to the determination of …

Chemistry

Study on determination of gold by solid phase extraction and flame atomic absorption spectrometry with multiwalled carbon nanotubes loaded pentathia-15-crown-5

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Li Yinke 1,2 , Huang Yun 2 , Hu Qiufen 2,3 , Hhuang Qilin 3 , Yang Guangyu 2,3
​​( 1 Southwest University, Chongqing 400715; Department of Chemistry, Yunnan Nationalities University, Kunming 650031 ; 2 Department of Chemistry, Yunnan Nationalities University, Kunming 650031; 3 Department of Chemistry, Yuxi Teacher’s College, Yuxi 653100 )

Abstract The solid phase extraction cartridge using multiwalled carbon nanotubes loaded pentathia-15-crown-5 (PT15C5) as sorbent was manufactured, and a solid phase extraction and flame atomic absorption spectrometry method for the determination of gold with this cartridge was studied. The gold can quantificationally adsorbed onto the graphitized carbon black cartridge when they pass the cartridge as pH 3.5 HAc-NaAC buffer medium. Then the gold can eluted from the cartridge with 0.1 mol/L Na2S2O3 solution. By this procedure, the gold in samples can be enriched with high times and most …

Chemistry

Preparation of MAA/TRIM molecularly imprinted polymers and binding selectivity for ciprofloxacin

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Gao Jungang, Liu Zhanli, Liu Pengyan, Jiang Ning
(College of Chemistry and Environmental Science, Baoding 071002,China)

Received Dec. 10, 2006.

Abstract  Molecular imprinted polymers (MIPs) for ciprofloxacin were synthesized using methacrylic acid as a functional monomer and trimethylolpropane trimethacrylate(TRIM) as a cross-linker. The binding property and recognition selectivity were studied by equilibrium binding test. The MIP showed high selectivity and specificity to ciprofloxacin, separation factor a=2.03. Scatachard analysis indicated that two kinds of sites were formed in MIP for ciprofloxacin and the imprinting mechanism was discussed.
Keywords  molecularly imprinted polymer；Ciprofloxacin；Molecular recognition

  1. INTRODUCTION
    Molecularly imprinted polymers (MIPs) are produced by forming a polymer around a molecule that is used as a template (print molecule). After removal of the print molecule, the polymer can be used as a selective binding medium for the print molecule or structurally related compounds. MIPs have been made selective for a large variety of compounds and have
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Chemistry

Immobilization of b-galactosidase on chitosan by 2, 4, 6-trichloro-1, 3, 5-triazine cethod

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Sun Sufang, Wang Chunyan, Zhang Yan, Liu Cuifen, Song Yongmei, Jia Jia
(College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China)

Received on Jul.7, 2007; Supported by the fund from the Natural Science Foundation of Hebei Province ( Grant No: B2007000146)

Abstract A new method to immobilize b-galactosidase on chitosan was proposed with 2, 4, 6-trichloro-1, 3, 5-triazine as crosslinking reagent for the first time. Under the best immobilization conditions, the mean activity yield of the immobilized enzyme determined was 47%, which was much higher than that obtained from glutaraldehyde method. Besides, this new method with 2, 4, 6-trichloro-1, 3, 5-triazine as crosslinking reagent was mild, reliable and reproducible, and the coupling reagent used was much cheaper than glutaraldehyde.
Keywords 2, 4, 6-trichloro-1, 3, 5- triazine, b-galactosidase, immobilization, chitosan

  1. INTRODUCTION
    Milk whey is the most important byproduct in cheese manufacturing. It represents 85-95% of processed milk by volume,
…
Chemistry

Simultaneous determination of ciprofloxacin, ofloxacin and norfloxacin in pharmaceutical preparations by capillary electrophoresis

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Abstract A new method was described for simultaneous determination of ciprofloxacin (CIP), ofloxacin (OFL) and norfloxacin (NOR) by capillary electrophoresis with a diode array detector at 280 nm. The separation conditions were investigated and optimized. A new medium, 30 mM sodium tetraborate buffer solution and 22 mM sodium dodecyl sulphate containing 5% (v/v) methanol (pH 8.7), was developed for the complete separation of the three quinolones. The excipients do not affect to separation and analysis. Calibration curves between peak area and concentration in the range 10-1000 mg/L for each compound have good linearity with a correlation coefficient (r) of greater than 0.999, and the detection limit£¨s/n£© was 7.90 mg/L for CIP£¬7.92 mg/L for OFL and 7.56 mg/L for NOR. This method has been successfully applied for simultaneous determination of CIP, OFL and NOR in the pharmaceutical preparations with rapid, accurate, and simple characteristics.
Keywords Capillary electrophoresis; Ciprofloxacin; Ofloxacin; …

Chemistry

Research progress of CTG repeats in structural biology

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Research progress of CTG repeats in structural biology

Hu Haiming, Xue Yonglai, Feng Xizeng (The Key Laboratory of Bioactive Materials Ministry of Education, China, College of Life Science, Nankai University, Tianjin, 300071)

Abstract Myotonic dystrophy type1(MD) is an autosomal dominant neuromuscular disease, its heredity mechanism is the expansions of CTG repeats in the 3′-untranslated region of the myotonic dystrophy protein kinase(DMPK). This paper introduces the structure features of CTG biochemical feature, expansion mechanism, factors that influence its expansion, and the relationship between expansion and MD.
Keywords Myotonic dystrophy, trinucleotide repeats CTG, expansion, structure, S-DNA

Advances in Structural Biology Research of CTG Repeat Sequence

Hu Haiming, Xue Yonglai, Feng Xizeng
(Key Laboratory of Bioactive Materials, Ministry of Education, School of Life Sciences, Nankai University, Tianjin 300071)

Abstract Myotonic dystrophy (MD) is an autosomal dominant neuromuscular disease. Its genetic mechanism is caused by abnormal expansion of CTG repeat sequence located in the …