The use of visual cues in the perception of non-native consonant contrasts

This study assessed the extent to which second-language learners are sensitive to phonetic information contained in visual cues when identifying a non-native phonemic contrast. In experiment 1, Spanish and Japanese learners of English were tested on their perception of a labial/ labiodental consonant contrast in audio (A), visual (V), and audio-visual (AV) modalities. Spanish students showed better performance overall, and much greater sensitivity to visual cues than Japanese students. Both learner groups achieved higher scores in the AV than in the A test condition, thus showing evidence of audio-visual benefit. Experiment 2 examined the perception of the less visually-salient /1/-/r/ contrast in Japanese and Korean learners of English. Korean learners obtained much higher scores in auditory and audio-visual conditions than in the visual condition, while Japanese learners generally performed poorly in both modalities. Neither group showed evidence of audio-visual benefit. These results show the impact of the language background of the learner and visual salience of the contrast on the use of visual cues for a non-native contrast. Significant correlations between scores in the auditory and visual conditions suggest that increasing auditory proficiency in identifying a non-native contrast is linked with an increasing proficiency in using visual cues to the contrast.     

Synthesis and antimicrobial activity of N-analogous corollosporines

Corollosporine is an antimicrobial metabolite, which was isolated from the marine fungus Corollospora maritima. Owing to its basic 4-hydroxyphthalic acid anhydride structure, it has become an attractive target for a structure/activity relationship modelling of derived compounds with potential antibiotic activity. In this regard we report on the straightforward synthesis of hetero analogous corollosporines, which were easily prepared by a three-step reaction sequence, taking advantage of a novel multicomponent reaction (AAD-reaction) and a subsequent aromatization/Grignard reaction protocol. Furthermore, the obtained products were tested in several biological assays to evaluate their antimicrobial activity.     

New synthetic protocols for the preparation of unsymmetrical bisindoles

Novel unsymmetrical bisindoles were synthesized by a solvent-free C-C bond-formation reaction under mild conditions. Starting from aziridines or hydroxyl precursors, indoles have been used as C-nucleophiles to form new pharmacologically interesting bisindoles via an electrophilic aromatic substitution pathway in good to excellent yields. [reaction: see text]     

Orientability of the Minor Director of Homeotropically Aligned Smectic‐A Elastomers in External Mechanical Fields

We present studies on bulk smectic‐A copolymer networks with end‐on attached homeotropically oriented mesogens that show spontaneous optical biaxiality at room temperature. Orthoscopic and conoscopic investigations under uniaxial extension in the layer planes give first evidence of the orientability of the minor director in mechanical fields yielding biaxial monodomains with 3‐d orientational long‐range order of all three principle axes. This is an important step towards the synthesis of permanently oriented biaxial monodomain elastomers for which highly interesting mechanical and optical properties are expected.     

Efficiency enhancement of Cu(In,Ga)Se2 thin‐film solar cells by a post‐deposition treatment with potassium fluoride

Alkali‐free Cu(In,Ga)Se₂(CIGS) absorbers grown on Mo‐coated alumina (Al₂O₃) substrates were doped with potassium (K) after CIGS growth by a potassium fluoride (KF) post‐deposition treatment (PDT). The addition of K to the absorber leads to a strong increase in cell efficiency from 10.0% for the K‐free cell to 14.2% for the K‐doped cell, mainly driven by an increase in the open‐circuit voltage V_oc and the fill factor FF, and to an increase in the net charge carrier density. Hence K doping by KF‐PDT is comparable to doping with Na.

     

Pattern formation during deformation of a confined viscoelastic layer: from a viscous liquid to a soft elastic solid

We study pattern formation during tensile deformation of confined viscoelastic layers. The use of a model system [poly(dimethylsiloxane) with different degrees of cross-linking] allows us to go continuously from a viscous liquid to an elastic solid. We observe two distinct regimes of fingering instabilities: a regime called "elastic" with interfacial crack propagation, where the fingering wavelength scales only with the film thickness, and a bulk regime called "viscoelastic," where the fingering instability shows a Saffman-Taylor-like behavior. We find good quantitative agreement with theory in both cases and present a reduced parameter describing the transition between the two regimes and allowing us to predict the observed patterns over the whole range of viscoelastic properties.     

Cascade Synthesis of Pyrroles from Nitroarenes with Benign Reductants Using a Heterogeneous Cobalt Catalyst

A bifunctional 3d-metal catalyst for the cascade synthesis of diverse pyrroles from nitroarenes is presented. The optimal catalytic system Co/NGr-C@SiO₂-L is obtained by pyrolysis of a cobalt-impregnated composite followed by subsequent selective leaching. In the presence of this material, (transfer) hydrogenation of easily available nitroarenes and subsequent Paal–Knorr/Clauson-Kass condensation provides >40 pyrroles in good to high yields using dihydrogen, formic acid, or a CO/H₂O mixture (WGSR conditions) as reductant. In addition to the favorable step economy, this straightforward domino process does not require any solvents or external co-catalysts. The general synthetic utility of this methodology was demonstrated on a variety of functionalized substrates including the preparation of biologically active and pharmaceutically relevant compounds, for example, (+)-Isamoltane.     

Colloidal Silica Rods: Material Properties and Fluorescent Labeling

In this paper, the characterization and fluorescent labeling of silica rods are reported. These rods are synthesized following a recently reported method. Material properties of the silica rods measured with NMR, elemental analysis, TGA, and porosimetry are compared with those of well‐established Stöber silica spheres. Additionally, silica rods are made suitable for quantitative real‐space studies by confocal microscopy. Several methods of fluorescent labeling to prepare rods with different fluorescent patterning, ranging from uniform fluorescence levels to gradients from one rod‐end to the other, and even patterns of several colors are presented and discussed.     

Procyanidins from Myrothamnus flabellifolia

From the ethyl acetate soluble fraction of an acetone-water extract of the twig tips of Myrothamnus flabellifolia Welw. (Myrothamnaceae), a variety of flavan-3-ols (epicatechin, epigallocatechin and their 3-O-galloylated analogues) and procyanidins (DP 8)-catechin], B4 [catechin-(4alpha --> 8)-epicatechin], B6 [catechin-(4alpha --> 6)-catechin] and catechin-(4alpha --> 8)-epigallocatechin along with the galloylated analogues B4-3'-O-gallate, procyanidin B2-3'-O-gallate [epicatechin-(4beta --> 8)-epicatechin-3-O-gallate], B2-3,3'-di-O-gallate, procyanidin B5-3,3'-O-gallate [epicatechin-3-O-gallate-(4beta --> 6)-epicatechin-3-O-gallate], catechin-(4alpha --> 8)-epigallocatechin-3-O-gallate, the trimer procyanidin C1-3'-O-gallate[epicatechin-(4beta --> 8)-epicatechin-(4beta --> 8)-epicatechin-3-O-gallate] and the new epicatechin-3-O-gallate-(4beta --> 6)-epicatechin-3-O-p-hydroxybenzoate. The structures were elucidated by 1D- and 2D-NMR experiments of their peracetylated derivatives, partial acid-catalysed degradation with phloroglucinol, ESI-MS and CD spectra.