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Y H Zeng

Publications and source records attributed to Y H Zeng.

4 recordsLinked to original sources
PubMed2001

Nested genetic algorithm for resolving overlapping spectra.

A nested genetic algorithm, including a genetic parameter level and a genetic implemented level, has been proposed and applied for resolving simulated overlapping spectra. Parameters of genetic algorithms (GA) were optimized by use of the genetic parameter level. The number of overlapping peaks was, moreover, detected simultaneously. Parameters of individual peaks in multiplets were computed by use of the genetic implemented level. It is obvious that the parameters of GA can be optimized and the number of overlapping peaks can be detected by itself. The optimization results are less affected than in traditional curve-fitting by the initial values of the parameters of the overlapping bands. Consequently, the nested genetic algorithm is superior to the curve-fitting technique for resolution of overlapping peaks.

Algorithms↗
PubMed2001

[Adsorptive voltammetric behavior of omeprazole and its application].

AIM: To study the electrochemical behavior of omeprazole (OPZ) and a new method for the determination of the compound was established by adsorptive stripping voltammetry. METHODS: Linear-sweep polarography and cyclic voltammetry were used. RESULTS: In a supporting electrolyte containing 0.1 mol.L-1 NH3-NH4Cl, a reduction peak of OPZ was observed by linear-sweep voltammetry at Hg electrode. The peak showed a potential of -1.04 V (vs Ag/AgCl at 100 mV.s-1) and adsorptive characteristics. The adsorbed species is most probably the neutral molecular of OPZ. The saturated adsorption of OPZ at Hg electrode is 9.55 x 10(-11) mol.cm-2 and every OPZ molecule occupies and area of 1.74 nm2. On the surface of the hanging mercury drop electrode, the adsorption of OPZ obeys Frumkin adsorption isotherm. The adsorption coefficient beta is 1.32 x 10(6), the Gibbs energy of adsorption delta G theta is -34.93 kJ.mol-1, the number of electrons transferred n is 4, the kinetics parameter alpha n alpha is 0.78, the rate constant of the surface electrode reaction ks is 0.18 s-1, the diffusion coefficient D of OPZ in solution is 1.03 x 10(-5) cm2.s-1. The detection limit of the adsorptive stripping voltammetry of OPZ is 2.0 x 10(-9) mol.L-1 under optimized condition. CONCLUSION: This indicates an irreversible process with adsorption.

Anti-Ulcer Agents↗
PubMed1980

Active products of porcine trypsin after autolysis.

Porcine trypsin obtained from pancreas residues subsequent to insulin removal undergoes autolysis when subjected to chromatography and gives rise to new forms of autolyzed products with intra-chain split at bonds Lys145-Ala146 and Arg105-Val106. Incubation of 1% solutions of porcine trypsin either at pH 5.0 or at pH 9.1 induces autolysis to give active products involving one or two specific cleavages of bonds Lys145-Ala146 and Arg105-Val106 or Lys131-Ser132, as well as inactive degraded products. No evidence has been obtained that on autolysis of porcine trypsin, and active fragment with molecular weight lower than that of the parent molecule was identified. The active forms of autolyzed products of porcine trypsin have almost the same specific activity as the intact enzyme when assayed against BAEE. They are of the same molecular weight as the parent molecule. These findings indicate that that active forms of autolyzed products maintain the specific three-dimensional structure essential for the catalytic activity of the trypsin molecule.

Amino Acid Sequence↗