Investigation of Fe structural environments in “leucite”-type framework silicates using a combination of Mössbauer and X-ray absorption spectroscopies

Synthetic iron-containing leucite-type phases have been studied using⁵⁷Fe Mössbauer spectroscopy in combination with X-ray absorption spectroscopy (XAFS and XANES). The Mössbauer and XAS data confirm that both Fe²⁺ and Fe³⁺ occupy tetrahedrally coordinated framework sites in the synthetic phases. In addition, information on Fe²⁺/Fe³⁺ ratios, cation site occupancies and first shell bond lengths has also been obtained.     

Magnetic ordering in gadolinium aluminate,GdAlO3

An analysis of Magneto-Electric Susceptibility, Magnetic Susceptibility and X-ray results has shown that the direction of sub lattice alinement in the antiferromagnetically ordered state of GdAlO₃ corresponds to the orthorhombic a-axis. This result is contrary to the previous analysis which favoured the b-axis.     

Photochemically knocking out glutamate receptors in vivo

AMPA (alpha-amino-3-hydroxy-5-methyl-4-isooxazole) receptors, a major subtype of ionotropic glutamate receptors (iGluRs), mediate the majority of the fast communication between neurons, and the activity-dependent trafficking of AMPA receptors at synapses plays a role in mammalian learning and memory. Here we describe the design, synthesis, and evaluation of a photoreactive AMPA receptor antagonist that provides a means of "knocking out" AMPA receptors present on the surface of cells. The antagonist, 6-azido-7-nitro-1,4-dihydroquinoxaline-2,3-dione (ANQX), was designed by introducing a photoreactive azido group onto a quinoxalinedione inhibitor scaffold. Computational docking of ANQX to the AMPA receptor ligand-binding core predicted efficient binding to AMPA receptors. Glutamate-evoked currents were reversibly blocked at micromolar ANQX concentrations prior to photolysis and irreversibly blocked following photolysis. ANQX provides a means of directly evaluating the trafficking of native AMPA receptors with unparalleled spatiotemporal resolution.     

Finite Elastic Deformations of a Tyre Modelled as an Ideal Fibre-Reinforced Shell

Vehicle tyres are anisotropic inhomogeneous fibre-reinforced shells which undergo finite elastic deformations. Calculation of their stress and deformation fields is a difficult task and is normally performed using the finite element technique. In this paper an attempt is made to provide an approximate analysis of the deformation field modelling the tyre as an ideal fibre-reinforced material. Radial-ply tyres are reinforced by a belt of fibres running around the wheel in the circumferential direction under the tread of the tyre. A second set of fibres lies in each radial cross-section, of the tyre and runs from the bead wire which seats against one wheel rim to the bead wire at the other wheel rim. We shall assume each radial cross-section of the tyre is in a state of plane strain and is formed from an arch of fibre-reinforced composite material which is reinforced in the hoop direction. This composite is assumed to be an ideal material which is inextensible in the fibre-direction and is incompressible. The plane-strain deformations of this section are examined and then used to analyse the deformation of the tyre as a whole.     

A more reactive trigonal-bipyramidal high-spin oxoiron(IV) complex with a cis-labile site

The trigonal-bipyramidal high-spin (S = 2) oxoiron(IV) complex [Fe(IV)(O)(TMG(2)dien)(CH(3)CN)](2+) (7) was synthesized and spectroscopically characterized. Substitution of the CH(3)CN ligand by anions, demonstrated here for X = N(3)(-) and Cl(-), yielded additional S = 2 oxoiron(IV) complexes of general formulation [Fe(IV)(O)(TMG(2)dien)(X)](+) (7-X). The reduced steric bulk of 7 relative to the published S = 2 complex [Fe(IV)(O)(TMG(3)tren)](2+) (2) was reflected by enhanced rates of intermolecular substrate oxidation.     

Metal Coordination Sphere Deformation Induced Highly Stokes‐Shifted,Ultra Broadband Emission in 2D Hybrid Lead‐Bromide Perovskites and Investigation of Its Origin

Published studies of layered (2D) (100)‐oriented hybrid lead‐bromide perovskites evidence a correlation between increased inter‐octahedral (Pb‐Br‐Pb) distortions and the appearance of broadband white light emission. However, the impact of distortions within their constituent [PbBr₆]^4? octahedra has yet to be assessed. Herein, we report two new (100)‐oriented 2D Pb‐Br perovskites, whose structures display unusually high intra‐octahedral distortions, whilst retaining minimal inter‐octahedral distortions. Using a combination of temperature‐dependent, power‐dependent and time‐resolved photoluminescence spectroscopic measurements, we show that increased intra‐octahedral distortion induces exciton localization processes and leads to formation of multiple photoinduced emissive colour centres. Ultimately, this leads to highly Stokes‐shifted, ultrabroad white light emission at room temperature.