29 research outputs found

    The power of VNA-driven quasi-optics to sense group molecular action in condensed phase systems

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    © © 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The authors would like to thank the Engineering and Physical Sciences Research Council (EPSRC, UK) for generous support (EP/1014845)

    Simulations reveal the role of composition into the atomic-level flexibility of bioactive glass cements

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    K. V. T. thanks ETT-489/2009 and TAMOP-4.2.1.B, Hungary. D. D. T. thanks the UK's Royal Society for the award of a Royal Society Industry Fellowship. This research utilised Queen Mary's MidPlus computational facilities, supported by QMUL Research-IT and funded by EPSRC grant EP/K000128/1. Via our membership of the UK's HEC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202), this work used the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk)

    The power of VNA-driven quasi-optics to sense group molecular action in condensed phase systems

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    © 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The versatility for quasi-optical circuits, driven by modern vector network analysers, is demonstrated for the purpose of low energy (meV) coherent spectroscopy. One such example is shown applied to the curing dynamics of a non-mercury-based dental cement. This highlights the special place the methodology holds as a `soft-probe' to reveal the time-resolved energetics of condensed phased systems as they self-organise to adopt their low energy state

    Spectroscopic Evidence for an Oxazolone Structure in Anionic b-Type Peptide Fragments

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    Infrared spectra of anionic b-type fragments generated by collision induced dissociation (CID) from deprotonated peptides are reported. Spectra of the b2 fragments of deprotonated AlaAlaAla and AlaTyrAla have been recorded over the 800–1800 cm–1 spectral range by multiple-photon dissociation (MPD) spectroscopy using an FTICR mass spectrometer in combination with the free electron laser FELIX. Structural characterization of the b-type fragments is accomplished by comparison with density functional theory calculated spectra at the B3LYP/6-31++G(d,p) level for different isomeric structures. Although diketopiperazine structures represent the energetically lowest isomers, the IR spectra suggest an oxazolone structure for the b2 fragments of both peptides. Deprotonation is shown to occur on the oxazolone α-carbon, which leads to a conjugated structure in which the negative charge is practically delocalized over the entire oxazolone ring, providing enhanced gas-phase stability

    New insights into the role of solution additive anions in Mg2+ dehydration: implications for mineral carbonation

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    Simulations of hydrated Mg2+, in the absence and presence of several solution additive anions, show that in pure liquid water Mg(H2O)62+ is the only stable coordination state; yet anions may stabilise undercoordinated five-hydration configurations. Solution composition can lower the barrier to Mg2+ dehydration and subsequent incorporation into the lattice of Mg-carbonates, promoting low-temperature crystallisation

    New insights into the role of solution additive anions in Mg2+ dehydration: implications for mineral carbonation (vol 23, pg 4896, 2021)

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    Simulations of hydrated Mg2+, in the absence and presence of several solution additive anions, show that in pure liquid water Mg(H2O)62+ is the only stable coordination state; yet anions may stabilise undercoordinated five-hydration configurations. Solution composition can lower the barrier to Mg2+ dehydration and subsequent incorporation into the lattice of Mg-carbonates, promoting low-temperature crystallisation
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