3,4-Epoxyperfluorooxolane in the synthesis of new fluorine-containing furo[3,4-b]quinoxaline derivatives

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Mahonia aquifolium Extracts Promote Doxorubicin Effects against Lung Adenocarcinoma Cells In Vitro

Mahonia aquifolium and its secondary metabolites have been shown to have anticancer potential. We performed MTT, scratch, and colony formation assays; analyzed cell cycle phase distribution and doxorubicin uptake and retention with flow cytometry; and detected alterations in the expression of genes involved in the formation of cell–cell interactions and migration using quantitative real-time PCR following treatment of lung adenocarcinoma cells with doxorubicin, M. aquifolium extracts, or their combination. MTT assay results suggested strong synergistic effects of the combined treatments, and their application led to an increase in cell numbers in the subG1 phase of the cell cycle. Both extracts were shown to prolong doxorubicin retention time in cancer cells, while the application of doxorubicin/extract combination led to a decrease in MMP9 expression. Furthermore, cells treated with doxorubicin/extract combinations were shown to have lower migratory and colony formation potentials than untreated cells or cells treated with doxorubicin alone. The obtained results suggest that nontoxic M. aquifolium extracts can enhance the activity of doxorubicin, thus potentially allowing the application of lower doxorubicin doses in vivo, which may decrease its toxic effects in normal tissues.     

Unraveling excited states of doped helium clusters

We discuss the use of generalized, symmetry-adapted, imaginary-time correlation functions to study the rotational spectrum of doped helium clusters within the frame of the reptation quantum Monte Carlo method. Analysis of these correlation functions allows one to enhance the computational efficiency in the calculation of weak spectral features, as well as to get a qualitative insight into the nature of the different lines. The usefulness of this approach is demonstrated by a study of the He-CO binary complex, used as a benchmark case, as well as by preliminary results for the satellite band recently observed in the IR spectrum of the CO2 molecule solvated in He nanodroplets.     

Myeloperoxidase-mediated oxidation of organophosphorus pesticides as a pre-step in their determination by AChE based bioanalytical methods

In order to improve the sensitivity of assays for inhibitors of the enzyme acetylcholine esterase (AChE), an effective method was developed for the conversion of the organophosphate pesticides (OPs) diazinon, malathion, chlorpyrifos, azinphos-methyl and phorate into more toxic inhibitors. This was accomplished by converting them from the thio form into their oxo form using the enzyme myeloperoxidase. The oxo forms, which are the only products of conversion, were determined by AChE bioassays, using either the free enzyme, or a flow injection analysis manifold with immobilized AChE and spectrophotometric detection. All modified OPs exhibited inhibitory power at ppb levels and within 10 min. The method is considered to represent an excellent means for improving the sensitivity of assays for determination of OPs.     

Synthesis,physicochemical characterization,and TD–DFT calculations of monothiocarbohydrazone derivatives

Structural Chemistry - Derivatives of thiocarbohydrazone studied so far have shown great biological activity such as antioxidant, antimicrobial, and anticancer. Most of these compounds are...     

Electrochemical formation of zinc selenide from acidic aqueous solutions

An investigation on electrochemical ZnSe thin film growth from acidic aqueous baths of Se(IV) and Zn(II) species is described. The range of co-deposition potentials is predicted on a thermodynamic basis according to a known electrochemical model. A study on the voltammetric behavior of Ti and Ni electrode substrates in the working solutions at various temperatures provides the main features of the applied electrochemical process. Cathodic electrodeposition at high temperatures (>65 °C) results in the formation of polycrystalline cubic, randomly oriented, ZnSe crystallites suffering, in general, from the presence of a crystalline Se phase in excess. Annealing of as-grown films adjusts the stoichiometry and leads to the production of semiconductive ZnSe with a band gap width of 2.7 eV. Electronic Publication     

Thermal and flammability behaviour of copolymers of N-(2, 4, 6-tribromophenyl)maleimide with some acrylates

The copolymers of N-(2, 4, 6-tribromophenyl)maleimide (TBPMI) with methyl acrylate, methyl methacrylate and acrylonitrile of different composition were prepared by free radical polymerization at low conversion. Their thermal behaviour was established by TGA measurements in helium atmosphere and flammability properties were determined by limiting oxygen index method. The higher TBPMI content in the copolymer led to a higher thermal stability and lower flammability particularly when Sb₂O₃ was used as a synergist.     

Generalized Alternating Direction Implicit Method for Projected Generalized Lyapunov Equations

We generalize an alternating direction implicit method for projected generalized Lyapunov equations. Low rank versions of this method is also presented that can be used to compute a low rank approximation of the solution of Lyapunov equations with symmetric, positive semidefinite right‐hand side. Numerical example is given. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)