Impact of residual extractives on the thermal stability of softwood Kraft pulp

Cellulose - Wood extractives are known to cause problems during the production of pulp and paper and to impact their mechanical properties. In the present work, we systematically explored whether...     

Vector valued Banach limits and generalizations applied to the inhomogeneous Cauchy equation

Aequationes mathematicae - In Prager and Schwaiger (Grazer Math Ber 363:171–178, 2015) the classical notion of Banach limits was used to solve the inhomogeneous Cauchy equation...     

Towards EPC-syntheses of the structural class of cochleamycins and macquarimicins. Part 1: EPC-synthesis of the hydrindene subunit of the cochleamycins

A racemic as well as an EPC-synthesis of the cis-hydrindene subunit of the cochleamycins, physiologically active microbial secondary metabolites, are reported. The five stereogenic centres of this subunit are introduced in high stereoselectivity in a short sequence by intermolecular Diels-Alder reaction, stereoselective methylation and hydride reduction. Cyclisation via nucleophilic addition, acidic fragmentation, regioselective Shapiro reaction and inversion of a secondary alcohol are the further key steps of these syntheses.     

Bioassay-Guided Isolation of Anti-Inflammatory Constituents of the Subaerial Parts of Cyperus articulatus (Cyperaceae)

Based on data from a previous ethnobotanical study in northern Angola, phytochemical investigations into the methanolic rhizomes and roots extract of Cyperus articulatus, monitored by in vitro assays, resulted in the recovery of 12 sesquiterpenes, 3 stilbenes, 2 phenolic acids, 1 monoterpene, and 1 flavonoid. Among them, 14 compounds were isolated for the first time from this species. Their inhibitory potential against nitric oxide (NO) production, as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, was evaluated in LPS-treated J774A.1 murine macrophages. Especially, both stilbene dimer trans-scirpusin B and trimer cyperusphenol B showed promising inhibitory activity against the production of the inflammatory mediator, NO, in a concentration-dependent manner (10–1 µM). The obtained data are the first results confirming the anti-inflammatory potential of C. articulatus and support its indigenous use as a traditional remedy against inflammation-related disorders.     

Cyclic deformation of polycrystalline Cu films

Fatigue impairs the reliability of macroscopic metallic components utilized in a variety of technological applications. However, the fatigue behaviour of thin metal films and small-scale components used in microelectronics and mechanical microdevices has yet to be explored in detail. The fatigue behaviour in submicrometre thin films is likely to differ from that in bulk material, since the volume necessary for the formation of dislocation structures typical of cyclic deformation in bulk material is larger than that available in thin films. The thin-film dimensions and microstructure, therefore, affect the microscopic processes responsible for fatigue. The fatigue behaviour of Cu films 0.4, 0.8 and 3.0 µm thick on polyimide substrates was investigated. The specimens were fatigued at a total strain amplitude of 0.5% using an electromechanical tensile-testing machine. This work focuses on the characterization of fatigue mechanisms and the resulting fatigue damage of thin Cu films. Extrusions similar to those observed in bulk material were found at the film surfaces after cyclic loading. Voids observed beneath the extrusions, close to the film-substrate interface, contributed significantly to thin-film failure. Thinner films were more fatigue resistant and contained fewer and smaller extrusions than thicker films did. A small thickness appears to inhibit void nucleation. This observation is explained in terms of vacancy diffusion and annihilation at free surfaces or grain boundaries. Transmission electron microscopy investigations confirmed that no long-range dislocation structures have developed during fatigue loading of the films investigated.     

Some remarks on the stability of the Cauchy equation and completeness

Aequationes mathematicae - It was proved in Forti and Schwaiger (C R Math Acad Sci Soc R Can 11(6):215–220, 1989), Schwaiger (Aequ Math 35:120–121, 1988) and with different methods in...     

Fast and improved separation of major coumarins in Ammi visnaga (L.) Lam. by supercritical fluid chromatography

The first supercritical fluid chromatography method for the determination of five major coumarins (dihydrosamidin, visnadin, samidin, khellin, and visnagin) in Ammi visnaga fruits is described. Their baseline separation was possible in less than 5 min by using a UPC² HSS C₁₈ SB column with 1.8 μm particle size and a mobile phase comprising CO₂, methanol, acetonitrile, and diethylamine. The type of stationary phase used was of particular relevance because, except for the selected one, the others did not resolve the two structural isomers dihydrosamidin and visnadin. Method validation confirmed that the procedure is linear (R² ≥ 0.9996) in a concentration range from 6 to 480 μg/mL, it is accurate (recovery rates: 97.2–103.6%) and precise (intraday deviation ≤ 6.6%, intraday deviation ≤ 1.7%); injecting 1 μL of standard solution, the determined limit of detection was below 1.9 μg/mL for all compounds. The analysis of different A. visnaga samples revealed their similar compositions, and khellin (0.75–1.01%) and visnagin (0.18–0.46%) were the dominant coumarins. Visnadin and dihydrosamidin, the individual quantification of which is described for the first time, were present at concentrations below 0.14%.     

Robust slice-selective broadband refocusing pulses

Slice-selective broadband refocusing pulses are of great interest in localized MR spectroscopy for improving spatial selectivity, reducing chemical-shift displacement errors, and reducing anomalous J modulation. In practice the bandwidth of RF pulses is limited by the maximum available B1 amplitude. The goal of the present work is to design slice-selective and broadband refocusing pulses which are tolerant against B1 deviations. Pulse design is performed by numerical optimization based on optimal control theory. A comprehensive study of different cost functions and their effect on the optimization is given. The optimized slice-selective broadband refocusing pulses are compared to conventional Shinnar-Le Roux (SLR), broadband SLR, and hyperbolic secant pulses. In simulations and experiments optimized pulses were shown to fulfill broadband slice specifications over a range of ±20% B1 scalings. Experimental validation showed a reduction of chemical-shift displacement error by a factor of 3 compared to conventional SLR pulses.