Improved anti-inflammatory and pharmacokinetic properties for superoxide dismutase by chemical glycosidation with carboxymethylchitin

O-carboxymethylchitin (molecular weight = 1.07 x 10(5), degree of carboxymethylation = 80%, degree of N-acetylation = 91%) was chemically attached to superoxide dismutase by the formation of amide linkages through a carbodiimide catalyzed reaction. The glycosidated enzyme contained about 1.8 mole of polysaccharide per mole of protein and retained 57% of the initial catalytic activity. The anti-inflammatory activity of the enzyme was 2.4 times increased after conjugation with the polysaccharide. The modified superoxide dismutase preparation was remarkably more resistant to inactivation with H(2)O(2) and its plasma half-life time was prolonged from 4.8 min to 69 h.     

Determination of organohalogen compounds and organic carbon as sum parameter in electronic waste

Metal-containing devices in electronic waste such as printed circuit boards can be recycled for the recovery of noble metals such as gold, silver, platinum or palladium using a thermal process. In this process the plastics are burned and more than 90% of the noble metals are transfered into a copper matrix. Finally the pure metals are refined by electrolysis. Because of the content of brominated flame retardants and chlorinated polymers in the plastics, formation of halogenated dibenzo-p-dioxins and dibenzofurans cannot be excluded. The use of modern filter techniques minimizes the emission of these substances. As a precaution the electronic waste is controlled for its content of organohalogen compounds and organic carbon. This work describes an analytical method for the determination of the sum of organohalogen compounds and organic carbon in electronic waste. The investigation of different charges of electronic waste in the fraction of particle size<0.1 mm show concentrations for the sum of organobromine compounds in the range of 0.2–4.8% originating from brominated flame retardants in the plastics. The total content of organochlorine compounds is <0.01–0.13%, showing that chlorinated plastics were efficiently removed before the thermal process. The content of organic carbon is between 13 and 27%. Because of the portion of fine particle size in relation to the total sample amount, the results have to be multiplied by a factor of about 0.25 to 0.3.     

Discrepancy and eigenvalues of Cayley graphs

We consider quasirandom properties for Cayley graphs of finite abelian groups. We show that having uniform edge-distribution (i.e., small discrepancy) and having large eigenvalue gap are equivalent properties for such Cayley graphs, even if they are sparse. This affirmatively answers a question of Chung and Graham (2002) for the particular case of Cayley graphs of abelian groups, while in general the answer is negative.     

Alternating terpolymerization of three non-homopolymerizable monomers

The free-radical terpolymerization of maleic anhydride (MSA), isobutyl vinyl ether (VIBE) and anethol (ANE) at 60°C is described. These three monomers do not homopolymerize under the conditions used. Binary copolymers are only obtained from MSA and one of the two investigated donor monomers, whereas the binary copolymerization of VIBE with ANE is not possible. In all terpolymers from these three non-homopolymerizable monomers the MSA content amounts to about 50 mol-%; VIBE is about twice as reactive as ANE. The terpolymerization can formally also be described under the assumption that two binary complexes (MSA/ANE (I) and MSA/VIBE (II)) are copolymerized. For this case the reactivity ratios r_I = 0,9 and r_II = 1,7 are obtained.