Physico-chemical measurements of CL-20 for environmental applications. Comparison with RDX and HMX

CL-20 is a polycyclic energetic nitramine, which may soon replace the monocyclic nitramines RDX and HMX, because of its superior explosive performance. Therefore, to predict its environmental fate, analytical and physico-chemical data must be made available. An HPLC technique was thus developed to measure CL-20 in soil samples based on the US Environmental Protection Agency method 8330. We found that the soil water content and aging (21 days) had no effect on the recoveries (>92%) of CL-20, provided that the extracts were kept acidic (pH 3). The aqueous solubility of CL-20 was poor (3.6 mg l(-1) at 25 degrees C) and increased with temperature to reach 18.5 mg l(-1) at 60 degrees C. The octanol-water partition coefficient of CL-20 (log KOW = 1.92) was higher than that of RDX (log KOW = 0.90) and HMX (log KOW = 0.16), indicating its higher affinity to organic matter. Finally, CL-20 was found to decompose in non-acidified water upon contact with glass containers to give NO2- (2 equiv.), N2O (2 equiv.), and HCOO- (2 equiv.). The experimental findings suggest that CL-20 should be less persistent in the environment than RDX and HMX.     

Separation of ferrichromes and other hydroxamate siderophores of fungal origin by reversed-phase chromatography

Iron(III) chelates of nineteen trihydroxamate siderophores of fungal origin, including ferrichromes, coprogen and triacetylfusarinine C, were separated on a preparative scale with a reversed-phase column using the octadecyl silica gels LRP-1 or LRP-2 as the stationary phase and a water-methanol gradient as the mobile phase. Using this system in combination with silica gel column chromatography, most siderophores can be obtained in pure form. Factors affecting the mobility of these compounds in the reversed-phase system are discussed.     

Cobalt-based nanocatalyst catalyzed one-pot four-component synthesis 2<Emphasis Type="Italic">H</Emphasis>-indazolo[2,1-b]phthalazine-triones under solvent-free condition

In this research, an efficient procedure for the one-pot four-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones catalyzed by a cobalt-based nanocatalyst (Co/Al₂O₃ nanocatalyst) is reported. The catalyst was prepared by a co-precipitation method and characterized by BET surface area, SEM, TEM, EDS and XRD analyses. A wide range of various aromatic aldehydes including electron-withdrawing and electron-releasing groups were applied and corresponding products obtained in high yields without any by-product. Moreover, the Co/Al₂O₃ is recyclable up to 7 consecutive runs by simple filtration.     

Spectroscopic and Molecular Modeling Based Approaches to Study on the Binding Behavior of DNA with a Copper (II) Complex

Blocking the division of tumor cells by small-molecules is currently of great interest for the design of new antitumor drugs. The interaction of a new metal complex with DNA was investigated through several techniques. Absorption spectroscopy and gel electrophoresis studies on the interaction of the Cu-complex of (2a-4mpyH)₂ [Cu(pyzdc)₂ (H₂O)₂].6 H₂O with DNA have shown that this complex can bind to CT-DNA with binding constant 3.99?×?10⁵ M^?1. The cyclic voltammetry (CV) responses of the metal complex in the presence of CT-DNA have shown that the metal complex can bind to CT-DNA through partial intercalation mode and this is consistent with molecular docking analysis, quenching process and thermal denaturation experiments. The cytotoxicity of this complex has been evaluated by MTT assay. The results of cell viability assay on DU145 cell line revealed that the metal complex had cytotoxic effects.     

Effect of multiple localized geometric imperfections on stability of thin axisymmetric cylindrical shells under axial compression

Stability of imperfect elastic cylindrical shells which are subjected to uniform axial compression is analyzed by using the finite element method. Multiple interacting localized axisymmetric initial geometric imperfections, having either triangular or wavelet shapes, were considered. The effect of a single localized geometric imperfection was analyzed in order to assess the most adverse configuration in terms of shell aspect ratios. Then two or three geometric imperfections of a given shape and which were uniformly distributed along the shell length were introduced to quantify their global effect on the shell buckling strength. It was shown that with two or three interacting geometric imperfections further reduction of the buckling load is obtained. In the ranges of parameters that were investigated, the imperfection wavelength was found to be the major factor influencing shell stability; it is followed by the imperfection amplitude, then by the interval distance separating the localized imperfections. In a wide range of parameters this last factor was recognized to have almost no effect on buckling stresses.     

Analysis of testosterone in human urine using molecularly imprinted solid-phase extraction and corona discharge ion mobility spectrometry

Analysis of testosterone was accomplished using corona discharge ion mobility spectrometry. Molecular imprinted polymer was used for the extraction and pre-concentration of testosterone. Analytical parameters including precision, dynamic range and detection limit were obtained. The linear dynamic range was from 10 to 250 ng/mL and the limit of detection was 0.9 ng/mL. The proposed method was used for analysis of testosterone in urine samples. A urine sample from a 3-year-old girl was used as the blank. The RSD was below 10%. The obtained results from the method were also compared with the standard method for analysis of testosterone using SPE-HPLC analysis. The results demonstrate the accuracy of the method.     

Global Existence for Capillary Water Waves

Consider the capillary water waves equations, set in the whole space with infinite depth, and consider small data (i.e., sufficiently close to zero velocity, and constant height of the water). We prove global existence and scattering. The proof combines in a novel way the energy method with a cascade of energy estimates, the space‐time resonance method and commuting vector fields. © 2015 Wiley Periodicals, Inc.     

Supply chain network downsizing with product line pruning using a new demand substitution

This paper presents an optimization model for downsizing a multi-product supply chain facing bankruptcy risk, where multi-functional production facilities are shared for producing a group of substitutable products. In order to determine the potential demand after discontinuation of certain product types, the proposed mixed integer programming model incorporates a new general formulation of demand substitution, which allows arbitrary demand diversion and arbitrary replacement rates between products under investigation. The new substitution formulation enables considering uneven substitutions for supply chain network design and therefore it extends currently used substitution approaches. A series of systematically generated downsizing cases confirm the validity of the here proposed approach, and illustrate how downsized chains can successfully adopt to the new circumstances.     

Melamine Trisulfunic Acid: An Efficient and Recyclable Solid Acid Catalyst for the Synthesis of 4,4′‐(Arylmethylene)‐bis‐(1H‐pyrazol‐5‐ols)

Melamine trisulfunic acid is employed as a recyclable catalyst for the condensation reaction of aromatic aldehydes with 3‐methyl‐l‐phenyl‐2‐pyrazolin‐5‐one. This condensation reaction was performed in ethanol under refluxing conditions giving 4,4′‐(arylmethylene)‐bis‐(3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐ols) in 80‐96% yields.     

Polymer-Supported Azide and Copper(I): Green Reusable Reagent and Catalyst for Click Cyclization

In this work, polymer-supported copper(I) iodide catalyst and macroporous polymer-supported azide reagent were used to simplify the synthesis of 1,4-disubstituted-1H-1,2,3-triazoles from α-bromo ketones/amides/esters following green chemistry principles. This new one-pot protocol facilitates the workup of the reaction and provides the products in short times and excellent yields. Heterogeneous catalyst and reagent can be reused at least for five runs without significant yield decreases.