Liquid phase oxidation of transition metals. Part 6. iron and copper complexes containing dimethylsulphoxide,dimethylformamide, and acetonitrile. Anomalous states of ligands

Summary Direct oxidation of iron and copper in a donor-acceptor medium, L + CCl₄, where L is dimethylsulphoxide, dimethylformamide or acetonitrile was employed to obtain complex compounds:cis-[FeCl₂(DMSO)₄]Cl] (3), 2 FeCl₃ · 3 DMSO (5), [FeCl(DMSO)₅][FeCl₄]₂] (6), [FeCl(DMSO)₅][Fe₂Cl₆O] (7),cis-[FeCl₂(DMF)₄][FeCl₄] (8), [Fe(MeCN)₆][FeCl₄]₂ (9) andcis-[CuCl₂(DMF)₂]₂ (10), The structures of complexes (9) and (10) have been established by x-ray diffraction analysis and compared with those of (3), (6), (7) and (8) which are reported elsewhere.The [FeCl(DMSO)₅][Fe₂Cl₆O] complex (7) is formed by oxidation of iron fromcis-[Fe^IIICl₂(DMSO)₄]₂[Fe^IICl₄] (4) in ethanol. One of the 5 DMSO molecules of (7) was found to be disordered; the Mössbauer spectroscopy data suggest that it can move within the cation coordination sphere.Mössbauer spectroscopy and x-ray diffraction analysis indicate electron isomerism in one of the complexes.For papers 4 and 5 of these series see refs. 1 and 2.     

Multifunctional Small Molecules as Potential Anti-Alzheimer’s Disease Agents

Alzheimer’s disease (AD) is a severe multifactorial neurodegenerative disorder characterized by a progressive loss of neurons in the brain. Despite research efforts, the pathogenesis and mechanism of AD progression are not yet completely understood. There are only a few symptomatic drugs approved for the treatment of AD. The multifactorial character of AD suggests that it is important to develop molecules able to target the numerous pathological mechanisms associated with the disease. Thus, in the context of the worldwide recognized interest of multifunctional ligand therapy, we report herein the synthesis, characterization, physicochemical and biological evaluation of a set of five (1a–e) new ferulic acid-based hybrid compounds, namely feroyl-benzyloxyamidic derivatives enclosing different substituent groups, as potential anti-Alzheimer’s disease agents. These hybrids can keep both the radical scavenging activity and metal chelation capacity of the naturally occurring ferulic acid scaffold, presenting also good/mild capacity for inhibition of self-Aβ aggregation and fairly good inhibition of Cu-induced Aβ aggregation. The predicted pharmacokinetic properties point towards good absorption, comparable to known oral drugs.     

Studies on the Use of Commercial Capillary Gas Chromatographic Columns as Diffusion Denuders

The possibility of using a piece of gas chromatographic capillary column as a tubular denuder for isolation and enrichment of organic pollutants present in air was studied. The partition coefficients (K_fs) of typical organic pollutants (benzene, chlorobenzene, toluene) between the gaseous phase and the denuder sorption layer were determined and effects of analyte concentration in the gaseous phase and gas flow rate on partitioning were studied. The partition coefficients were found to be constant in the studied range of concentration and gaseous mixture flow rate. A piece of a capillary column coated with polydimethylosiloxane can be used as a tubular denuder.     

Fefferman’s SAK principle and a priori estimates for second order operators

Abstract We prove in details the higher codimensional version of Theorem 1.1 [11]. This provides a complete proof of Fefferman’s SAK Principle for a class of PDO’s with symplectic characteristic manifold. Keywords: A priori estimates, General theory of PDO’s     

The effect of polysialic acid on molecular dynamics of model membranes studied by 31P NMR spectroscopy

The paper reports the results of our study on the dynamics of model phospholipid membranes studied by 31P NMR spectroscopy. The 31P NMR spectra of multilamellar vesicles in temperatures below the main phase transition of PC are reported. The 31P NMR spectra revealed changes caused by an increase of the membrane fluidity when polysialic acid (polySia) was applied as a modifying agent. The presence of polySia in the external environment of the phospholipid vesicles changes the motional freedom in the region of phosphate group of lipids. Increase of polysialic acid concentration changes structural properties of a membrane by increasing its fluidity.     

Analysis of lower modes of vibration of rectangular plates of linearly varying thickness

The title problem is solved assuming that the thickness varies symmetrically with respect to the x-axis. The edges defined by $\text{x = ± a/2}$ are elastically restrained against rotation while the remaining edges are clamped or simply supported.Approximate expressions for four of the lower natural frequencies of vibration (including the fundamental) are given.A forced vibrations situation is also dealt with.     

Noise emission during the first powerboat race in an Alpine lake and potential impact on fish communities

In order to assess the effects of high-speed boating on fish communities, noise levels were measured during the first Class 1 powerboat race on the Austrian Lake Traunsee. The noise spectra were compared to natural ambient noise and hearing abilities of four native fish species. Sound pressure levels (SPLs) were significantly elevated during the training heats and the race compared with natural levels, reaching up to 128 dB re 1 microPa (instantaneous SPL) at a distance of 300 m to the powerboats. Continuous equivalent SPLs were significantly lower during training and the pole position race compared to the race itself because fewer boats were simultaneously on the lake. The hearing abilities of the native hearing specialists and generalists were investigated. While carp and roach (two cyprinids) showed enhanced auditory sensitivity typical for hearing specialists, perch and whitefish were much less sensitive to sounds. Comparisons between power boat noise spectra and audiograms showed that the cyprinids can detect the boats up to several hundred meters distance because the main noise energy is well within the most sensitive hearing range. The hearing generalists, however, probably only perceive the first harmonic of the boat noise at close distances.     

Surface remelting of 316 L + 434 L sintered steel: microstructure and corrosion resistance

This study presents arc surface remelting of three types of sintered stainless steels carried out in order to constitute a homogeneous microstructure in the surface layer which is free from open and interconnected porosity. The main aim of this treatment was to improve functional properties of the sinters analysed, especially their resistance to pitting corrosion. The sinters were obtained from powders of 316 L and 434 L steels. The PM austenitic-ferritic stainless steels are used mainly in the automotive industry, but their general application is still limited due to relatively poor corrosion properties when compared to casts or wrought components. This study used the gas tungsten arc welding (GTAW) process as a method of economical surface treatment. The effect of surface treatment was evaluated based on macro- and microstructural observations, energy-dispersive X-ray spectroscopy (EDX) analysis, X-ray phase analysis, measurements of surface roughness and electrochemical examinations. It was found that a cellular or mixed cellular and dendritic structure was formed in the remelted zone of the sinters after remelting. X-ray analysis demonstrated that application of remelting contributes to formation of the austenitic phase in the surface layer. The corrosion resistance of the remelted surface layers was evaluated using polarization tests in 0.5 M NaCl solution. It was found that arc surface remelted layers exhibit much better anticorrosive properties than sinters without surface treatment. Microstructural observations of the surface of specimens after electrochemical tests showed only a few single pits in the remelted layer, while the surface of initial sinters was much more corroded.