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  • 1
    Electronic Resource
    Electronic Resource
    Purification and characterization of nitric oxide synthase from Staphylococcus aureus (2003)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 222 (2003), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We previously reported the presence of nitric oxide synthase (NOS) in Staphylococcus aureus ATCC6538P whose activity was induced by methanol. In the present study, the methanol-induced NOS was purified 900-fold from S. aureus by means of Mono Q ion exchange column, 2′,5′-ADP-agarose affinity column, and Superdex 200HR gel permeation column chromatography. The purified bacterial NOS showed two protein bands with 67 and 64 kDa molecular mass on SDS–PAGE. However, the molecular mass of the NOS was 135 kDa on Superdex 200HR gel permeation column chromatography, indicating that the native enzyme exists as a heterodimer. This bacterial NOS had Km value of 13.4×10−6 M for l-arginine and Vmax of 35.3 nmol min−1 mg−1 protein. In addition, reduced nicotinamide adenine dinucleotide phosphate, flavin adenine dinucleotide, flavin mononucleotide, tetrahydrobiopterin, calmodulin and Ca2+ were required as cofactors in the conversion of l-arginine to l-citrulline, and NOS inhibitors selectively inhibited the activity of the purified NOS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0378-1097(03)00254-4
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  • 2
    Electronic Resource
    Electronic Resource
    Purification and characterization of protein methylase II from Helicobacter pylori (2001)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 195 (2001), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Protein methylase II (AdoMet:protein-carboxyl O-methyltransferase, EC 2.1.1.24) was identified and purified 115-fold from Helicobacter pylori through Q-Sepharose ion exchange column, AdoHcy-Sepharose 4B column, and Superdex 200 HR column chromatography using FPLC. The purified preparation showed two protein bands of about 78 kDa and 29 kDa molecular mass on SDS–PAGE. On non-denaturing gel electrophoresis, the enzyme migrated as a single band with a molecular mass of 410 kDa. In addition, MALDI-TOF-MS analysis and Superdex 200 HR column chromatography of the purified enzyme showed a major mass signal with molecular mass values of 425 kDa and 430 kDa, respectively. Therefore, the above results led us to suggest that protein methylase II purified from H. pylori is composed of four heterodimers with 425 kDa (4×(78+29)=428 kDa). This magnitude of molecular mass is unusual for protein methylases II so far reported. The enzyme has an optimal pH of 6.0, a Km value of 5.0×10−6 M for S-adenosyl-l-methionine and a Vmax of 205 pmol methyl-14C transferred min−1 mg−1 protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.2001.tb10497.x
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  • 3
    Electronic Resource
    Electronic Resource
    Nano Composite Membranes of Sulfonated Poly(2,6-Dimethyl-1,4-Phenylene Oxide)/Poly(2,6-Diphenyl-1,4-Phenylene Oxide) Copolymer and SiO〈sub〉2〈/sub〉 for Fuel Cell Application (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 26-28 (Oct. 2007), p. 835-838 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The Sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) / poly(2,6-diphenyl-1,4-phenyleneoxide) (S-PPO) was prepared by oxidative coupling polymerization with 2,6-dimethyl phenol,2,6-diphenyl phenol, CuCl(І) and pyridine, and followed sulfonation with chlorosulfonic acid.Copolymer was consisted of 2,6-diphenyl phenol 30 mol% and 2,6-dimethyl phenol 70 mol%.Organic-inorganic nano composite membranes were prepared with copolymer and a series of SiO2nanoparticles (20 nm, 4, 7 and 10 wt%). The composite membranes were cast from dimethylsulfoxidesolution. The membranes were studied by differential scanning calorimetry (DSC) andthermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interactionof sulfonated polymers with water and methanol. S-PPO copolymer and nano composite membranesexhibited proton conductivities from 0.79×10-3 to 0.98×10-3 S/cm, water uptake from 21.70 to24.77 %, IEC from 0.720 to 0.955 meq/g and methanol diffusion coefficients from 2.97×10-7 to3.70×10-7 cm2/S
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.26-28.835.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and Characterization of Multi-Sulfonated Poly(Aryl Ether Ketone)s Proton Exchange Membranes (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 544-545 (May 2007), p. 1065-1068 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A series of sulfonated poly(aryl ether ketone)s were prepared by condensationpolymerization with bisphenol A and 1,2-bis(4-fluorobenzoyl)-3,6-diphenylbenzene, and followedby sufonation with chlorosulfonic acid. The polymers were characterized by Fourier transforminfra-red (FTIR) and ion exchange capacity (IEC) to verify sulfonation. Differential scanningcalorimetry (DSC) and thermogravimetric analysis (TGA) were carried out to investigate thethermal stability of the prepared membranes. The membranes were found to possess all the requisiteproperties; Ion exchange capacity (3.31meq./g), glass transition temperatures (207-230°C), and lowaffinity towards methanol (2.04x10-6-4.15x10-7 cm2/S)
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/16/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.544-545.1065.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Organic-Inorganic Nano Composite Membranes of Sulfonated Poly(ether Sulfone-Ketone) Copolymer and SiO〈sub〉2〈/sub〉 for Fuel Cell Application (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 534-536 (Jan. 2007), p. 97-100 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Novel bisphenol-based wholly aromatic sulfonated poly(ether sulfone-ketone) copolymerand organic-inorganic composite membranes were prepared for operation 80°C in polymerelectrolyte membrane fuel cell (PEMFCs). The copolymer were synthesized by direct aromaticnucleophilic substitution polycondensation of 4,4-difluorobenzophenone, 2,2’-disodiumsulfonyl-4,4’-fluorophenylsulfone (40mole% of bisphenol A) and bisphenol A. Polymerization proceededquantitatively to high molecular weight in N-methyl-2-pyrrolidinone at 180°C. Organic-inorganiccomposite membranes were obtained by mixing organic polymers with hydrophilic SiO2 obtainedby sol-gel process. The polymer and a series of composite membranes were studied by FT-IR,1HNMR, differential scanning calorimetry (DSC) and thermal stability. The proton conductivity asa function of temperature decreased as SiO2 content increased, but methanol permeabilitydecreased. The nano composite membranes were found to poses all requisite properties; Ionexchange capacity (1.2meq./g), glass transition temperatures (164-183[removed info]), and low affinity towardsmethanol (4.63-1.08x10-7 cm2/S)
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/14/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.534-536.97.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis and Characterization of Branched Sulfonated Poly(ether Sulfone-Ketone) Copolymer and Organic-Inorganic Nano Composite Membranes (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 534-536 (Jan. 2007), p. 121-124 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Branched sulfonated poly(ether sulfone-ketone) copolymer was prepared with bisphenolA, 4,4-difluorobenzophenone, sulfonated chlorophenyl sulfone (40mole% of bisphenol A) andTHPE (1,1,1-tris-p-hydroxyphenylethane) as a branching agent. THPE was used 0.4 mol% ofbisphenol A to synthesize branched copolymers. Organic-inorganic nano composite membraneswere prepared with copolymer and a series of SiO2 nanoparticles (20 nm, 4, 7 and 10 wt%). Thecomposite membranes were cast from dimethylsulfoxide solutions. The films were converted fromthe salt to acid forms with dilute hydrochloric acid. The membranes were studied by differentialscanning calorimetry (DSC) and thermogravimetric analysis (TGA). Sorption experiments wereconducted to observe the interaction of sulfonated polymers with water and methanol. Branchedcopolymer and nano composite membranes exhibited proton conductivities from 1.12x10-3 to6.04x10-3 S/cm2, water uptake from 52.9 to 62.4%, IEC from 0.81 to 1.21 meq/g and methanoldiffusion coefficients from 1.2x10-7 to 1.5x10-7 cm2/S
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/14/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.534-536.121.pdf
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  • 7
    Electronic Resource
    Electronic Resource
    Detection of Helicobacter pylori DNA in Human Biliary Tree and Its Association with Hepatolithiasis (2000)
    Springer
    Digestive diseases and sciences 45 (2000), S. 1405-1412 
    Details
    ISSN: 1573-2568
    Keywords: Helicobacter pylori ; bile ; biliary epithelium ; gallstone ; hepatolithiasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Recently, several authors have reported that Helicobacter pylori DNA has been found in human bile. The aim of this study is to investigate the presence of H. pylori in the biliary tree of Koreans, including the bile, biliary epithelium, and gallstones. This study analyzed intrahepatic bile, bile duct tissue, and gallstones from 43 patients with hepatobiliary disease (PTCS group), gallbladder bile and tissue from 23 patients with gallbladder disease (CCT group), and eight patients without hepatobiliary disease (control group). H. pylori was examined by PCR with two different primers. PCR was positive in 4/43 (9.3%) by 26 kDa protein antigen primer and in 5/43 (11.6%) by urease A gene primer in bile from the PTCS group. However, in intrahepatic duct tissue, PCR was positive in only one case. PCR of gallbladder bile, tissue, and intrahepatic duct stones was negative. Upon intrahepatic bile analysis, the pH was significantly lower in PCR-positive than in negative cases (P 〈 0.05). In conclusion, H. pylori DNA may be present in the bile when there are certain environmental changes, such as lowered pH; however, H. pylori does not colonize the bile duct epithelium. We could find no pathogenetic role for H. pylori in the formation of hepatolithiasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005572507572
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