On a generalized proximal point method for solving equilibrium problems in Banach spaces

We introduce a regularized equilibrium problem in Banach spaces, involving generalized Bregman functions. For this regularized problem, we establish the existence and uniqueness of solutions. These regularizations yield a proximal-like method for solving equilibrium problems in Banach spaces. We prove that the proximal sequence is an asymptotically solving sequence when the dual space is uniformly convex. Moreover, we prove that all weak accumulation points are solutions if the equilibrium function is lower semicontinuous in its first variable. We prove, under additional assumptions, that the proximal sequence converges weakly to a solution.     

Snapshot of the palladium(II)-catalyzed oxidative biaryl bond formation by X-ray analysis of the intermediate diaryl palladium(II) complex

Pd(II) caught in the act: The diaryl Pd(II) intermediate of a Pd(II)-catalyzed oxidative biaryl bond formation proceeding via a double C-H bond activation has been isolated and fully characterized, including an X-ray crystal structure analysis. Stabilization due to chelation by adjacent pivaloyloxy and acetyl groups has allowed the isolation of this long-sought crucial intermediate. On gentle warming, the complex is transformed into a carbazole product, and the catalytically active Pd(II) species is regenerated by oxidation with Cu(II).     

New aeruginazoles,a group of thiazole-containing cyclic peptides from Microcystis aeruginosa blooms

Three related cyclic peptides, aeruginazole DA1497 (1), aeruginazole DA1304 (2), and aeruginazole DA1274 (3), were isolated from the freshwater cyanobacteria, Microcystis aeruginosa, bloom material collected on October 2007 from the Dalton water-reservoir in Northern Israel. Aeruginazoles DA1304 (2), DA1338 (4), and DA1372 (5) were isolated as an inseparable mixture from a bloom material of M. aeruginosa collected from the same water-reservoir on August 2000. Their structures were elucidated using a combination of various spectroscopic techniques, mainly NMR and MS, while the absolute stereochemistry of the chiral centers were determined by Marfey’s method. Aeruginazoles 1–3 were tested in various bioassays (antibacterial, cytotoxicity, and protease inhibition). Aeruginazole DA1497 (1) showed a mild antimicrobial activity against Staphylococcus aureus, but was inactive like the rest of the compounds in all other bioassays.     

On Weak and Strong Kuhn–Tucker Conditions for Smooth Multiobjective Optimization

We consider a smooth multiobjective optimization problem with inequality constraints. Weak Kuhn?CTucker (WKT) optimality conditions are said to hold for such problems when not all the multipliers of the objective functions are zero, while strong Kuhn?CTucker (SKT) conditions are said to hold when all the multipliers of the objective functions are positive. We introduce a new regularity condition under which (WKT) hold. Moreover, we prove that for another new regularity condition (SKT) hold at every Geoffrion-properly efficient point. We show with an example that the assumption on proper efficiency cannot be relaxed. Finally, we prove that Geoffrion-proper efficiency is not needed when the constraint set is polyhedral and the objective functions are linear.     

Conical intersection seams in polyenes derived from their chemical composition

The knowledge of conical intersection seams is important to predict and explain the outcome of ultrafast reactions in photochemistry and photobiology. They define the energetic low-lying reachable regions that allow for the ultrafast non-radiative transitions. In complex molecules it is not straightforward to locate them. We present a systematic approach to predict conical intersection seams in multifunctionalized polyenes and their sensitivity to substituent effects. Included are seams that facilitate the photoreaction of interest as well as seams that open competing loss channels. The method is based on the extended two-electron two-orbital method [A. Nenov and R. de Vivie-Riedle, J. Chem. Phys. 135, 034304 (2011)]. It allows to extract the low-lying regions for non-radiative transitions, which are then divided into small linear segments. Rules of thumb are introduced to find the support points for these segments, which are then used in a linear interpolation scheme for a first estimation of the intersection seams. Quantum chemical optimization of the linear interpolated structures yields the final energetic position. We demonstrate our method for the example of the electrocyclic isomerization of trifluoromethyl-pyrrolylfulgide.     

Electrochemical Determination of Inorganic Contaminants in Automotive Fuels

This article critically reviews the electroanalytical methods developed for the determination of inorganic contaminants in automotive fuels. Topics include the methods applied to the analysis of liquid biofuels and liquid fossil fuels for which different strategies were developed based on analytes and sample matrices. Special attention is given to electrodes, detection techniques, and sample preparation protocols (when required). Analytes include anions such as chloride, sulfate and phosphate, and mainly metallic species such as sodium, potassium, magnesium, calcium, cadmium, copper, iron, lead, manganese, mercury, nickel, platinum, tin, vanadium, and zinc. Suggestions for future research are also presented.     

l- and d-Proline Thiosemicarbazone Conjugates: Coordination Behavior in Solution and the Effect of Copper(II) Coordination on Their Antiproliferative Activity

Two enantiomerically pure thiosemicarbazone-proline conjugates with enhanced aqueous solubility, namely, 2-hydroxy-3-methyl-(S)-pyrrolidine-2-carboxylate-5-methylbenzaldehyde thiosemicarbazone [l-Pro-STSC or (S)-H(2)L] and 2-hydroxy-3-methyl-(R)-pyrrolidine-2-carboxylate-5-methylbenzaldehyde thiosemicarbazone [d-Pro-STSC or (R)-H(2)L] have been synthesized and characterized by elemental analysis, spectroscopic methods (UV-vis and (1)H and (13)C NMR), and electrospray ionization mass spectrometry. The metal complexation behavior of l-Pro-STSC, stoichiometry, and thermodynamic stability of iron(II), iron(III), copper(II), and zinc(II) complexes in 30% (w/w) dimethyl sulfoxide/H(2)O solvent mixture have been studied by pH-potentiometric, UV-vis-spectrophotometric, circular dichroism, electron paramagnetic resonance, (1)H NMR spectroscopic, and spectrofluorimetric measurements. By the reaction of CuCl(2)·2H(2)O with (S)-H(2)L and (R)-H(2)L, respectively, the complexes [Cu[(S)-H(2)L]Cl]Cl and [Cu[(R)-H(2)L]Cl]Cl have been prepared and comprehensively characterized. An X-ray diffraction study of [Cu[(R)-H(2)L]Cl]Cl showed the formation of a square-planar copper(II) complex, which builds up stacks with interplanar separation of 3.3 ?. The antiproliferative activity of two chiral ligands and their corresponding copper(II) complexes has been tested in two human cancer cell lines, namely, SW480 (colon carcinoma) and CH1 (ovarian carcinoma). The thiosemicarbazone-proline conjugates l- and d-Pro-STSC show only moderate cytotoxic potency with IC(50) values of 62 and 75 μM, respectively, in CH1 cells and >100 μM in SW480 cells. However, the corresponding copper(II) complexes are 13 and 5 times more potent in CH1 cells, based on a comparison of IC(50) values, and in SW480 cells the increase in the antiproliferative activity is even higher. In both tested cell lines, l-Pro-STSC as well as its copper(II) complex show slightly stronger antiproliferative activity than the compounds with a d-Pro moiety, yielding IC(50) values of 4.6 and 5.5 μM for [Cu(l-Pro-STSC)Cl]Cl in CH1 and SW480 cells, respectively.     

catena‐Poly­[fac‐tri­chloro­methyl­tin(IV)‐μ‐[meso‐1,2‐bis­(phenyl­sulfinyl)­ethane‐O:O′]]

In the title compound, [SnCl₃(CH₃)(C₆H₅SOCH₂)₂]_n, the octahedral Sn^IV centres are bridged by meso‐1,2‐bis­(phenyl­sulfinyl)­ethane ligands forming infinite chains along the [100] direction.     

Methods of multivariate data analysis applied to the investigation of fen soils

Fen soils from two sites of the Rhin-Havel-Luch, a peatland in the north-east of Germany, have been investigated. The samples have been collected in two horizons, representing different degrees of degradation and mineralisation of peat. Gravimetric measurements, energy dispersive X-ray fluorescence (EDXRF), elemental analysis, and ¹H low resolution nuclear magnetic resonance (LR-NMR) of the fen soil samples have been performed. By multivariate analysis of all the experimental data, especially by the principal component analysis (PCA) and by the cluster analysis, respectively, it was possible to classify the fen soils, to identify their characteristic properties, to detect temporal and local variations, and to prove representative field sampling. Furthermore, the correlation between variables of the applied analytical methods could be interpreted in context to the composition of fen soils and mutual influences of their properties.     

WDX Analysis of Rapidly Quenched Nd-Fe-B Alloys with Ti + C Additives

 Quenched stoichiometric Nd-Fe-B alloys with Ti + C additives, which improve the hard magnetic properties, were investigated by EPMA technique. The exact quantitative wavelength dispersive analysis meets with two problems: the carbon blank value and the C-Kα line coincidence with Nd-Mγ, Nd-Mα and Nd-Mζ of higher diffraction orders. The carbon blank value depends on the special residual gas pressure in the recipient and was determined by repeated measurements of a carbon free iron reference specimen e.g. with subsequent corrections of the carbon content. The second problem can be solved by blanking out the Nd induced contribution to the C-Kα region by a differential detection mode. In this case an energy discriminator was used to set a lower and an upper level in order to suppress the neighbouring coincident lines. The optimized analysis allowed an exact determination of carbon content in all investigated phases.