Abelian varieties with finite abelian group action

An automorphism of an abelian variety induces a decomposition of the variety up to isogeny. There are two such results, namely the isotypical decomposition and Roan’s decomposition theorem. We show that they are essentially the same. Moreover, we generalize in a sense this result to abelian varieties with action of an arbitrary finite abelian group. An early version of this article was inadvertently published before all the revisions had been completed and then retracted [https://doi.org/10.1007/s00013-018-1244-3]. This article is the final peer reviewed version.

     

SALS,WAXS and mechanical properties of heat‐treated thermotropic polymers

The influence of heat treatment on the texture, microstructure and tensile mechanical properties of extruded thin films of a series of high‐performance thermotropic liquid crystal polymers (LCPs) was investigated. LCPs based on random units of hydroxybenzoic acid (B), hydroxynaphthoic acid (N), terephthalic acid (TA) and biphenol (BP) were kindly supplied by the former Hoechst Celanese Corp as 50 µm thick extruded tapes. The LCPs, denoted B‐N, COTBP and RD1000, have B and N as common comonomers and vary the other comonomers. Thus, this study also enables the investigation of the influence of monomer composition on microstructure and mechanical properties. Heat treatments were carried out at temperatures close to the solid‐to‐nematic transition (T_s→n) for periods up to 5 h, under dry air conditions. The thermal treatment produced either two endotherms or a small increase of T_s→n (B‐N and RD1000), or increased significantly T_s→n (COTBP). Moreover, when heat treatment was carried out approximately 40°C below the respective T_s→n, the mechanical Young's modulus, E, along the extrusion axis, increased for all LCPs. Strikingly, for COTBP, E increased over 100% relative to the as‐extruded film. The results also showed that the optimum treatment time for improving the Young modulus, under dry air atmosphere, was between 3 and 4 h. Wide‐angle X‐ray scattering showed a significant sharpening of crystalline reflections and concentration of the 002 meridional reflection as a result of thermal treatment, suggesting the elimination of defects and a better alignment of the molecular chains along the extrusion axis. This would explain the increase in tensile modulus. Copyright © 2013 John Wiley & Sons, Ltd.     

The Preparation Of 2-[4,5-Dihydro-3-Aryl-5-Isoxazolyl]-Phenols From C(α),O-Dilithiooximes and Lithiated Hydroxyaryl Aldehydes

C(a), O-Oximes were dilithiated in excess lithium diisopropylamide, and the resulting intermediates were condensed with lithiated hydroxyphenyl aldehydes and related materials and cyclized with acid to afford 2-[4,5-dihydro-3-aryl-5-isoxazolyl]phenols, substituted 4,5-dihydroisoxazoles (2-isoxazolines).     

A Convenient Method for the Phosphorylation of Phenols with Diethyl Cyanophosphonate

Phosphorylation of phenols with diethyl cyanophosphonate in methylene chloride solution at 0°C is an easy, rapid and good yielding reaction.     

Regiospecific synthesis of 1-acetamide-5-methoxy-2-oxindoles in two steps: (Ugi-SN2)/xanthate mediated free radical cyclization

A series of twelve novel 1-acetamide-5-methoxy-2-oxindoles were prepared in moderate to good yields (30–88%) by an Ugi-S_N2 one pot process with a xanthate mediated free radical cyclization. Additionally, Density Functional Theory (DFT) based calculations were performed at UB3LYP/6-311G(d) level in order to rationalize the energy profile of the xanthate mediated free radical cyclization because the benzo-fused γ-lactams (ortho products) were obtained as sole regioisomers over the spiro β-lactams (ipso products).     

Development of an adapted version of polar organic chemical integrative samplers (POCIS-Nylon)

POCIS (polar organic chemical integrative samplers) are increasingly used for sampling polar compounds. Although very efficient for a wide range of pollutants, the classic configuration of the device has a number of limitations, in particular for the sampling of highly polar analytes and hydrophobic compounds. This study presents a new version of the POCIS passive sampler which uses a highly porous Nylon membrane of 30 μm pore size, enabling the sampling of hydrophobic pollutants and improving the accumulation rate of other pollutants. This newly designed tool and the classic POCIS were both tested during a laboratory experiment to evaluate the accumulation kinetics of a selection of pesticides and pharmaceuticals. The observed results show unexpected accumulation kinetics for the new version of POCIS. To explain the data, the use of an intraparticulate diffusion model was required, which also enabled us to propose another explanation of the burst effect observed with the classic POCIS, primarily related to the potential wetting of the device as the first step in the accumulation of compounds.

Diamond electrode facilitated electrosynthesis of water and wastewater treatment oxidants

While diamond electrodes have been commonly used to generate ^?OH to treat a variety of persistent water and wastewater micropollutants, mass transfer limitations and the non-selective, short-lived nature of the ^?OH restrict the degradation to the solution at, or near, the electrode surface. However, diamond electrodes can generate oxidizing species that facilitate micropollutant degradation in the bulk water solution. These include persulfate, sulfate radicals, peroxodiphosphate, ferrate, permanganate, reactive chlorine species, hydrogen peroxide, and ozone, which have been reported during electrochemical treatment of water with diamond electrodes. Although still restricted to specialized applications, recent studies, summarized in this review, have proven the electrogeneration of these additional oxidant species to be effective. They have shown the adaptability and potential of diamond electrode-based water treatment to mitigate the presence of micropollutants in water.     

Capillary electrophoresis method for analysis of inorganic and organic anions related to habitability and the search for life

In situ missions of exploration require analytical methods that are capable of detecting a wide range of molecular targets in complex matrices without a priori assumptions of sample composition. Furthermore, these methods should minimize the number of reagents needed and any sample preparation steps. We have developed a method for the detection of metabolically relevant inorganic and organic anions that is suitable for implementation on in situ spaceflight missions. Using 55 mM acetic acid, 50 mM triethylamine, and 5% glycerol, more than 21 relevant anions are separated in less than 20 min. The method is robust to sample ionic strength, tolerating high concentrations of background salts (up to 900 mM NaCl and 300 mM MgSO₄). This is an important feature for future missions to ocean worlds. The method was validated using a culture of Escherichia coli and with high salinity natural samples collected from Mono Lake, California.     

Homogeneous and unimolecular gas‐phase thermal decomposition kinetics of methyl benzoylformate: experimental and theoretical study

The kinetics of the gas‐phase thermal decomposition of the α‐ketoester methyl benzoylformate was carried out in a static system with reaction vessel deactivated with allyl bromide, and in the presence of the free radical inhibitor propene. The rate coefficients were determined over the temperature range of 440–481 °C and pressures from 32 to 80 Torr. The reaction was found to be homogenous, unimolecular and obey a first‐order rate law. The products are methyl benzoate and CO. The temperature dependence of the rate coefficient gives the following Arrhenius parameters: log₁₀ k (s^?1) = 13.56 ± 0.31 and E_a (kJ mol^?1) = 232.6 ± 4.4. Theoretical calculations of the kinetic and thermodynamic parameters are in good agreement with the experimental values using PBE1PBE/6‐311++g(d,p). A theoretical Arrhenius plot was constructed at this level of theory, and the good agreement with the experimental Arrhenius plot suggests that this model of transition state may describe reasonably the elimination process. These results suggest a concerted non‐synchronous semi‐polar three‐membered cyclic transition state type of mechanism. The most advanced coordinate is the bond breaking C^δ+‐‐‐^δ‐OCH₃ with an evolution of 66.7%, implying this as the limiting factor of the elimination process. Copyright © 2014 John Wiley & Sons, Ltd.