The iron binding properties and antioxidant activities of compounds with hydroxy-keto binding sites, 3-hydroxychromone, 5-hydroxychromone, and sulfonated morin were investigated. For these compounds, prevention of iron-mediated DNA damage and kinetics of Fe(II) oxidation were studied in aqueous solutions close to physiological pH (pH 6). 3-Hydroxychromone and sulfonated morin inhibit iron-media...

0014-3057/$ see front matter 2010 Published b doi:10.1016/j.eurpolymj.2010.03.005 * Corresponding author. Tel.: +82 2 958 5299; fax E-mail address: [email protected] (H.-J. Kim). Polymer blending is used to modify or improve the dimensional and thermal stability of any two different polymers or copolymers. In this study, both sulfonated polybenzimidazole homopolymer (MS-p-PBI 100) and sulfonat...

Investigations of protein-polyelectrolyte complexes are important in the design of many biomedical applications that include enzyme immobilization, drug delivery, biosensor design, and in bioprocessing where complexation with polyelectrolytes is used to prevent protein aggregation and for protein purification. In this work, we choose to study the effect of polyelectrolyte stereochemistry on the...

A flavin reductase, which is naturally part of the ribonucleotide reductase complex of Escherichia coli, acted in cell extracts of recombinant E. coli strains under aerobic and anaerobic conditions as an "azo reductase." The transfer of the recombinant plasmid, which resulted in the constitutive expression of high levels of activity of the flavin reductase, increased the reduction rate for diff...

The introduction of sulfonic acid modified silica in Nafion nanocomposite membranes is a good method of improving the Nafion performance at high temperature and low relative humidity. Sulfonic acid-modified silica is bifunctional, with silica phase expected to offer an improvement in membranes hydration while sulfonic groups enhance proton conductivity. However, as discussed in this paper, this...

The role of vascular permeability in the preferential accumulation of photosensitize» in tumor tissue was investigated. Two murine tumors [experimental mammary tumor carcinoma (EMT-6) and methylcholanthrene-induced rhabdomyosarcoma (MIS)] and a human bladder carci noma (EJ) were grown s.c. on the flank in athymic nude mice and analyzed for in vivo vessel permeability, vascular permeability fac...

Direct copolymerization of sulfonated and non-sulfonated difluorodiphenyl sulfones as dihalide monomers with hydroquinone and also 4,4'-(4,4'-sulfonylbis-(1,4-phenylene)bis(oxy)) diphenol as diols led to preparation of two series of poly(arylene ether sulfone)s. Copolymers with different degrees of sulfonation (40, 50 and 60%) were synthesized in order to evaluate their potential for fuel cell ...

The ability to chemically wire ionomer films to electrode surfaces can promote transport near interfaces and impact a host of energy-related applications. Here, we demonstrate proof-of-concept principles for the surface-initiated ring-opening metathesis polymerization (SI-ROMP) of norbornene (NB), 5-butylnorbornene (NBH4), and 5-perfluorobutylnorbornene (NBF4) from Pt-modified gold substrates a...

the hydrolysis of sodium borohydride as a source of hydrogen gas is studied at different mole ratios of h+ to nabh4. the sulfonated porous carbon (spc) is used as a source of hydrogen ion and catalyst. it is found that the sulfonated porous carbon exhibits high activity for the hydrolysis of nabh4 to generate hydrogen gas at room temperature in comparison to amberlyst-15 and nafion-nr50. the ki...

Boric acid-pyridine mixture is presented as mild catalyst for polycondensation of semi-esters of ethylene glycol, in situ-generated by “cyclic anhydrideediol” reaction scheme from maleic, succinic and phthalic anhydrides. This catalyst system was demonstrated to give colorless polyesters in low molecular weights (Mn: 1650e1950 Da) within 4 h at 130 C 1H NMR spectra of the polyesters derived fro...