Regio- and diastereoselective synthesis of bis- and tetrakisadducts of C70 by directed remote functionalization using Tröger base tethers

Double Bingel cyclopropanation of C70 with bismalonates featuring Tr?ger base derivatives as chiral spacers afforded bisadducts with almost perfect regio- and stereoselectivity. The excellent directing property of these rigidly folded spacers in the remote functionalization of the higher fullerene was further highlighted by the selective formation of a product with a novel bisaddition pattern involving the C(7)-C(22) and C(33)-C(34) bonds of C70. Enantiomerically pure bisadducts of C70 were prepared by highly diastereoselective transformations of bismalonates incorporating optically pure Tr?ger base tethers. The absolute configuration of these bisadducts was established by comparison of circular dichroism (CD) spectra with data reported in the literature. For the first time, optically active tetrakisadducts of a fullerene were prepared by two sequential chiral-spacer-controlled remote functionalizations.     

Oblique orientated alpha-helices and their prediction

Oblique orientated alpha-helices possess hydrophobicity gradients, which allow the parent alpha-helices to penetrate the membrane at a shallow angle, thereby destabilising membrane lipid organisation and promoting a range of biological processes. These alpha-helices occur in a variety of membrane interactive proteins and a number of techniques have been developed to guide their identification using sequence data alone. Hydrophobicity profiling, which provides a one-dimensional analysis of sequence data, identified only 30% of known tilted peptides in a control dataset and was thus of limited predictive use. In contrast, extended hydrophobic moment plot methodology and amphipilic profiling which take residue distribution into account and provide two-dimensional analysis of primary structural data, were found to be good indicators of tilted peptide structure. Amphiphilic profiling identified 67% of tilted peptides in the control dataset and showed that potentially, approximately 40% of transmembrane alpha-helices possess tilted peptide structure. However, it has been shown that extending these simple methods to take into account the three-dimensional spatial distribution of residues gives no clear additional benefit to identifying tilted peptides.     

Stirring unmagnetized plasma

A new concept for spinning unmagnetized plasma is demonstrated experimentally. Plasma is confined by an axisymmetric multicusp magnetic field and biased cathodes are used to drive currents and impart a torque in the magnetized edge. Measurements show that flow viscously couples momentum from the magnetized edge (where the plasma viscosity is small) into the unmagnetized core (where the viscosity is large) and that the core rotates as a solid body. To be effective, collisional viscosity must overcome the ion-neutral drag due to charge-exchange collisions.     

High Performance Fe Porphyrin/Ionic Liquid Co‐catalyst for Electrochemical CO2 Reduction

The efficient and selective catalytic reduction of CO₂ is a highly promising process for both of the storage of renewable energy as well as the production of valuable chemical feedstocks. In this work, we show that the addition of an ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate, in an aprotic electrolyte containing a proton source and FeTPP, promotes the in situ formation of the [Fe⁰TPP]^2? homogeneous catalyst at a less negative potential, resulting in lower overpotentials for the CO₂ reduction (670 mV) and increased kinetics of electron transfer. This co‐catalysis exhibits high Faradaic efficiency for CO production (93 %) and turnover number (2 740 000 after 4 hour electrolysis), with a four‐fold increase in turnover frequency (TOF) when compared with the standard system without the ionic liquid.     

Third International Synchrotron Radiation Circular Dichroism Spectroscopy Meeting

The International Synchrotron Radiation Circular Dichroism (SRCD) Spectroscopy Meeting was held at the Physikzentrum, Bad Honnef, Germany on May 17–20, 2015, as the 590^th WE-Heraeus-Seminar. It was the third in the series of SRCD Workshops, following the first one held at the Daresbury Synchrotron (UK) in 2001, and the second at the Beijing Synchrotron Radiation Facility (BSRF) and the Institute of High Energy Physics (IHEP) in 2009. SRCD2015 was organized by Dr. Jochen Bürck, Prof. Anne Ulrich, and Dr. Dirk Windisch (all of Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Germany) and Prof. Bonnie Ann Wallace (Birkbeck College, University of London, UK). It was aimed at both synchrotron CD beamline scientists and scientific users of the beamlines, and included participants from 14 countries. For the first time, representatives of all operational SRCD beamlines worldwide were present at the same meeting, and scientists developing two new SRCD beamlines also participated.     

Doppler Effect Reconsidered

Doppler effect, as currently formulated. uses numerical phase invariance and any linear coordinate transformations with identity transformations of nonzero spatial coordinates transverse to a rectilinear uniform relative motion; this is shown to subtly deny presumed motion, angular aberration effects, and Doppler effect. A critical review of past Doppler effect experiments confirms (10⁻³ to 10⁻⁷) a classical Doppler effect formulation that does not involve an ether concept, numerical phase invariance, or the use of any coordinate transformations.     

Conducting polymers electromechanical actuators and strain sensors

Electromechanical actuators are being investigated for a wide range of applications in medical, electronics and industrial areas. One attractive application is to incorporate conducting polymer fibre actuators into fabrics for use in prosthetic applications. In this paper, the design of polypyrrole fibre actuators for use in a glove to open and close the human hand (for assisting those with paralysis or hand injuries) is described. The key requirements for this application are the simultaneous generation of 16 mm of contractile movement and 2.9 N of force. Although not critical in the first prototypes, eventually it will also be necessary to produce a rate of movement of around 10 mm sec⁻¹. The effect of the geometry of polypyrrole actuators is examined in this paper and it is shown that a tubular geometry is superior to conventional flat films. Another aspect of the practical use of actuator materials is their control. Fabric strain gauges with polymer actuators is a convenient means for providing feedback control to the actuating element. The fabric strain gauges ideally articulate with fibre actuators to give both the actuating and sensing function in the same fabric structure.