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Periodic sequences over finite fields have been used as key streams in private-key cryptosystems since the 1950s. Such periodic sequences should have a series of cryptographic properties in order to resist many attack methods. The binary generalized cyclotomic periodic sequences, constructed by the cyclotomic classes over finite fields, have good pseudo-random properties and correlation properties. In this paper, the linear complexity and minimal polynomials of some generalized cyclotomic sequences over GF( q ) have been determined where q = p m and p is an odd prime. Results show that these sequences have high linear complexity over GF( q ) for a large part of odd prime power q , which means they can resist the linear attack method. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aldoxime dehydratase was engineered to accept benzyl substrates by a semi-rational protein design. • The amino acid residues in the substrate access tunnel affect the substrate transportation. • Two catalytic processes of oxidation and dehydration were coupled to convert benzyl amines to nitrile derivatives. • The chemoenzymatic cascade was conducted under mild conditions without highly toxic cyanide. A chemoenzymatic strategy has been implemented to synthesize nitriles from benzyl amines under mild conditions. Aldoxime dehydratase (Oxd) plays a decisive role to convert aldoximes into corresponding nitriles. However, natural Oxds commonly exhibit extremely low catalytic capacity toward benzaldehyde oximes. Here, we engineered the OxdF1 from Pseudomonas putida F1 to enhance its catalytic efficiency toward benzaldehyde oximes by a semi-rational design strategy. The protein structure-based CAVER analysis indicates that M29, A147, F306, and L318 are located adjacent to the substrate tunnel entrance of OxdF1, which were responsible for the transportation of substrate into the active site. After two rounds of mutagenesis, the maximum activities of the mutants L318F and L318F/F306Y were 2.6 and 2.8 U/mg respectively, which were significantly higher than the wild OxdF1 of 0.7 U/mg. Meanwhile, the lipase type B from Candida antarctica was functionally expressed in Escherichia coli cells to selectively oxidize benzyl amines to aldoximes using urea-hydrogen peroxide adduct (UHP) as an oxidant in ethyl acetate. To merge the oxidation and dehydration reactions, a reductive extraction solution was added to remove the residue UHP, which is critical to eliminate its inhibition on the Oxd activity. Consequently, nine benzyl amines were efficiently converted into corresponding nitriles by the chemoenzymatic sequence. [ABSTRACT FROM AUTHOR]

Abstract: The objective of the study was to obtain pharmacokinetic parameters for melamine and blend of melamine (MEL) and cyanuric acid (CYA) in rainbow trout (Oncorhynchus mykiss). The single target dosage of MEL (20mg/kg bw) and the blend of MEL and CYA (5 and 1.67mg/kg bw, respectively) were designed and plasma samples were collected at 30min, 1, 4, 8, 12, 20, 24, 36, 48, 72, 144 and 240h sequentially. An optimized method for simultaneous determination of MEL and CYA in plasma and animal tissues by LC–MS/MS was used. The data were shown to best fit a non-compartment model with first order processes of linear characters for melamine, with half-life (t 1/2) of 32.2–32.9h, clearance (Cl z / F ) of 35.9–36.6ml/h/kg, and volume of distribution (V ss) of 1.67–1.74l/kg. Withdrawal of CYA was much more rapid than that of MEL with higher Cl z / F (783.56ml/h/kg) and shorter t 1/2 (7.92h). T max of MEL20 and MEL5 were 12 and 20h, respectively, which showed that T max of MEL5 was delayed when MEL and CYA were given together. The results are quite different from those in mammals and showed much slower elimination of MEL and CYA from rainbow trout body. [Copyright &y& Elsevier]