Minimizing the cycle time of multiple-product processing networks with a fixed operation sequence,setups, and time-window constraints

We solve a special case of the single-robot cyclic scheduling problem with a fixed robot operation sequence and time window constraints on processing times. It generalizes the known single-part fixed-sequence problems into the one to cover a processing network with multiple part types and setup time requirements between the processing steps for different parts at the shared stations. The objective is to minimize the cycle time. We prove that this problem is equivalent to the parametric critical path problem, and propose a strongly polynomial time solution algorithm which uses a new labeling procedure to identify all feasible parameter values. The proposed algorithm is based on an extension to the known Bellman–Ford algorithm.     

A new mechanism of acyl group transfer in the reaction catalyzed by D-glyceraldehyde-3-phosphate dehydrogenase

D-Glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) catalyzes the oxidative phosphorylation of its substrate in a two-step reaction. Asa result of the first, oxidativestep, the covalent intermediate where in 3-phosphoglyceroyl moiety is bound to Cys149 of the active center is subjected to nucleophilic attack by inorganic phosphate, but remains resistant to hydrolytic decomposition. This ensures tight coupling of oxidation with phosphorylation in glycolysis. In this article, we present the experimental evidence for the conversion of GAPDH into a form capable of performing the reaction in the absence of inorganic phosphate. The structural basis for this conversion is the oxidation of a cysteine residue (probably Cys 153) into a sulfenic acid derivative under mild conditions to affect the integrity of the essential Cys 149. As a result, an intram olecular transfer of 3-phosphoglyceroyl group from the active center Cys 149 to Cys 153 becomes possible with subsequent hydrolysis of the sulfenyl carboxylate intermediate.     

Potentiometric and volumetric determination of 6-mercaptopurine

Three methods for the determination of 6-mercaptopurine in the pure state and in tablets are described. One method is based on the reaction of this compound with silver ions, whereby an equivalent amount of nitric acid is liberated, the latter being determined potentiometrically with sodium hydroxide. The other two methods involve titration with chloramine-T, with potentiometric and visual end-point-detection. All methods afford accurate and reproducible results and can be used for routine assay of 6-mercaptopurine in tablets.     

The μ-dependence of the effective weak Hamiltonian andK→2π amplitudes in chiral-bag model

This paper studies the μ-dependence of the operator matrix elements. Although the μ-dependence must in principle cancel as illustrated in the paper by using a simple pedagogical model, in practice the choice of μ markedly influences the theoretical predictions forK→2π decays.     

Über das Resen des Manila-Elemiharzes

Ohne Zusammenfassung     

Novel structurally characterized o-semiquinonato PCP-pincer nickel complexes

Structural study of dialkyl (PCP)-pincer o-semiquinonato nickel complexes indicated sloped relative positions of bi- and tri-dentate ligands. It became bright confirmation of propositions made on the base of their EPR spectra followed by molecular modelling.     

Neues Verfahren zur Bestimmung des Extraktes im Weine

Ohne Zusammenfassung