Transitivity and Dense Periodicity for Graph Maps

In 1984, Blokh proved [A. M. Blockh, On transitive mappings of one-dimensional branched manifolds, Differential-Difference Equations and Problems of Mathematical physics (Russian), Akad. Nauk Ukrain. SSR Inst. Mat., Kiev, 131, pp. 3–9, 1984] that any topologically transitive continuous map from a graph into itself which has periodic points has a dense set of periodic points and has positive topological entropy (in this proof a crucial role is played by the specification property, which implies these two statements). Also, he characterized the topologically transitive continuous graph maps without periodic points. Unfortunately, this clever paper is only available in Russian (except for a translation to English of the statements of the theorems without proofs—see [A. M. Blockh, The connection between entropy and transitivity for one-dimensional mappings, Uspekhi Mat. Nauk, 42(5(257)) (1987), pp. 209–210]).     

Synthesis of new halo-containing acetylenes and their application to the synthesis of azoles

The convenient synthesis of ten halo- and an isoxazole-containing acetylenes from the reaction of acetylenes with n-butyl lithium and subsequent reaction with an electrophile agent (ethyl trichloroacetate, ethyl dichloroacetate, trifluoroacetic anhydride, 3-methylisoxazol-5-carbonyl chloride, carbon tetrachloride and 1,1,1-trifluoro-4-ethoxy-3-buten-2-one) in moderated to good yields is reported. The application of 1,1,1-trichloro-4-phenyl-3-butyn-2-one on the synthesis of two azoles is also showed.     

Gas Chromatographic Method for Analysis of p-Synephrine in Citrus aurantium L. Products

A method has been developed and validated for the identification and quantification of p-synephrine in Citrus aurantium L. products. The approach comprises GC-FID analysis followed by GC-MS confirmation after clean-up by solid phase extraction with a strong cation-exchange phase and derivatization with cyclohexanone. Oxazolidine derivative of p-synephrine was subjected to analysis by nuclear magnetic resonance (¹H and ¹³C NMR), GC-FID and GC-MS. The GC method was validated and was found to be linear in the range of 125–500 mg%. Intra-day and inter-day precisions were 3.60 and 3.59%, respectively. Mean recovery from extract of C. aurantium was 78.1 ± 3.64%. The selectivity of the method was further improved by confirmation of oxazolidine derivative of p-synephrine by GC-MS.     

Electric charge systems moving with the velocity of light and associated with charge creation

A discussion is given of certain electromagnetic fields associated with charges moving with the velocity of light which are associated with zero magnetic field, and the creation of charge. The stress energy tensor associated with charge creation is also discussed and it is shown that the stress energy tensor includes a term which may be interpreted as a shear.     

Isolation of NO(3)(-)-N as 1-phenylazo-2-naphthol (Sudan-1) for measurement of delta(15)N

The conversion of nitrate (NO(3)(-)) to 1-phenylazo-2-naphthol (Sudan-1) has been examined as a method for natural abundance measurement of delta(15)N of NO(3)(-). The reaction results in dilution of NO(3)(-)-N with only one reagent-derived N and the product is readily concentrated from dilute samples by reverse phase chromatography. There is systematic isotopic fractionation during the reaction, but this can be allowed for by analysing known NO(3)(-) standards along with each sample set. Sudan-1 prepared from surface water samples containing approximately 50 &mgr;g NO(3)(-)-N can be analysed by automated continuous flow isotope ratio mass spectrometry with a precision of 0.2 per thousand (one standard deviation) and the accuracy is not affected by interference from other nitrogenous species in the sample or reagents. Copyright 1999 John Wiley & Sons, Ltd.     

四乙基氯化胺-乙醇胺低共熔溶剂高效捕集CO2的研究

本文采用一步合成法制备不同摩尔比的TEAC-MEA DES;通过测定熔点,以及分析核磁和红外得出TE-AC-MEA DES之间是依靠氢键作用形成的DES.DES通过化学吸附CO2,生成了氨基甲酸酯,从而实现CO2的捕集;还研究了温度、HBA/HBD摩尔比、水含量、气体流速对DES吸收CO2的影响,结果表明CO2的吸收量...     

QUANTITATIVE METHODS FOR DECISION SUPPORT IN THE ICELANDIC FISHING INDUSTRY

Abstract Modern fisheries already collect vast amount of data, for example, through ERP systems and electronic log‐books. It is however well known that the data are rarely used for improving operational decision making. By converting this data into useable information, decision making in the fishing industry could be improved. This paper attempts to show that quantitative methods can be of use in many aspects of decision making in the fishing industry. The paper proposes a hierarchically structured decision support process based on two different optimization models for supporting the long‐ and short‐term decision making in fisheries. For long‐term planning the paper proposes a linear optimization model that describes the entire operation of a vertically integrated seafood company. For short‐term decision making the paper proposes a mixed integer linear optimization model to assist in organizing vessel trips and deciding catch location with regard to raw material quality and yield obtained in processing.     

AcquaAlta: a directional approach to the solvation of ligand-protein complexes

Water molecules mediating polar interactions in ligand-protein complexes can substantially contribute to binding affinity and specificity. To account for such water molecules in computer-aided drug design, we performed an extensive search in the Cambridge Structural Database (CSD) to identify the geometrical criteria defining interactions of water molecules with ligand and protein. In addition, with ab initio calculations the propensity of ligand hydration was evaluated. Based on this information, we developed an algorithm (AcquaAlta) to reproduce water molecules bridging polar interactions between ligand and protein moieties. This approach was validated with 20 crystal structures and yielded a match of 76% between experimental and calculated water positions. When water molecules establishing only weak interactions with the protein were neglected, the match could be improved to 88%. Supported by a pharmacophore-based alignment tool, the solvation algorithm was then applied to the docking of oligopeptides to the periplasmic oligopeptide binding protein A (OppA). Calculated waters based on the crystal poses matched an average of 66% of the experimental waters. With water molecules calculated based on the docked ligands, the average match with the experimental waters dropped to 53%.