1,496 research outputs found

    An organic fluorophore-nanodiamond hybrid sensor for photostable imaging and orthogonal, on-demand biosensing

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    Organic fluorescent probes are widely used to detect key biomolecules; however, they often lack the photostability required for extended intracellular imaging. Here we report a new hybrid nanomaterial (peroxynanosensor, PNS), consisting of an organic fluorescent probe bound to a nanodiamond, that overcomes this limitation to allow concurrent and extended cell-based imaging of the nanodiamond and ratiometric detection of hydrogen peroxide. Far-red fluorescence of the nanodiamond offers continuous monitoring without photobleaching, while the green fluorescence of the organic fluorescent probe attached to the nanodiamond surface detects hydrogen peroxide on demand. PNS detects basal production of hydrogen peroxide within M1 polarised macrophages and does not affect macrophage growth during prolonged co-incubation. This nanosensor can be used for extended bio-imaging not previously possible with an organic fluorescent probe, and is spectrally compatible with both Hoechst 33342 and MitoTracker Orange stains for hyperspectral imaging.Malcolm S. Purdey, Patrick K. Capon, Benjamin J. Pullen, Philipp Reineck, Nisha Schwarz, Peter J. Psaltis, Stephen J. Nicholls, Brant C. Gibson and Andrew D. Abel

    Searching for Faint Comoving Companions to the α Centauri system in the VVV Survey Infrared Images

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    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2017 Crown Copyright. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.The VVV survey has observed the southern disk of the Milky Way in the near infrared, covering 240 deg2^{2} in the ZYJHKSZYJHK_S filters. We search the VVV Survey images in a \sim19 deg2^{2} field around α\alpha Centauri, the nearest stellar system to the Sun, to look for possible overlooked companions that the baseline in time of VVV would be able to uncover. The photometric depth of our search reaches YY\sim19.3 mag, JJ\sim19 mag, and KSK_S\sim17 mag. This search has yielded no new companions in α\alpha Centauri system, setting an upper mass limit for any unseen companion well into the brown dwarf/planetary mass regime. The apparent magnitude limits were turned into effective temperature limits, and the presence of companion objects with effective temperatures warmer than 325K can be ruled out using different state-of-the-art atmospheric models. These limits were transformed into mass limits using evolutionary models, companions with masses above 11 MJup_{Jup} were discarded, extending the constraints recently provided in the literature up to projected distances of dPeer reviewedFinal Published versio

    Gibbs attractor: a chaotic nearly Hamiltonian system, driven by external harmonic force

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    A chaotic autonomous Hamiltonian systems, perturbed by small damping and small external force, harmonically dependent on time, can acquire a strange attractor with properties similar to that of the canonical distribution - the Gibbs attractor. The evolution of the energy in such systems can be described as the energy diffusion. For the nonlinear Pullen - Edmonds oscillator with two degrees of freedom the properties of the Gibbs attractor and their dependence on parameters of the perturbation are studied both analytically and numerically.Comment: 8 pages RevTeX, 3 figure

    The Partition Function and Level Density for Yang-Mills-Higgs Quantum Mechanics

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    We calculate the partition function Z(t)Z(t) and the asymptotic integrated level density N(E)N(E) for Yang-Mills-Higgs Quantum Mechanics for two and three dimensions (n=2,3n = 2, 3). Due to the infinite volume of the phase space Γ\Gamma on energy shell for n=2n= 2, it is not possible to disentangle completely the coupled oscillators (x2y2x^2 y^2-model) from the Higgs sector. The situation is different for n=3n = 3 for which Γ\Gamma is finite. The transition from order to chaos in these systems is expressed by the corresponding transitions in Z(t)Z(t) and N(E)N(E), analogous to the transitions in adjacent level spacing distribution from Poisson distribution to Wigner-Dyson distribution. We also discuss a related system with quartic coupled oscillators and two dimensional quartic free oscillators for which, contrary to YMHQM, both coupling constants are dimensionless.Comment: 10 pages, LaTeX; minor changes; version accepted for publication as a Letter in J. Phys.

    Non-Abelian Excitations of the Quark-Gluon Plasma

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    We present new, non-abelian, solutions to the equations of motion which describe the collective excitations of a quark-gluon plasma at high temperature. These solutions correspond to spatially uniform color oscillations.Comment: 8 pages LaTex, 1 figure (not included; available upon request), Saclay preprint T94/0

    “It’s like my kid came back overnight”: Experiences of trans and non-binary young people and their families seeking, finding and engaging with clinical care in England

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    Background: Trans and non-binary children and young people in England, UK struggle to gain access to affirming clinical care, despite the international research evidence pointing towards this best practice approach. Concurrently, they are subject to constant discussion in UK national media and politics, where many negative assumptions are made about their needs, experiences and clinical provision. Their journey to seek appropriate care has not yet been documented. Aims: We trace the experiences of trans and non-binary children and youth and their families in their decision to seek, searches for and experiences with affirmative and non-affirmative clinical input for help with their gender. Method: 27 dyadic, semi-structured interviews were undertaken with trans and non-binary children and young people and their parents from 13 families. Results: The process of seeking support via National Health Service clinical routes in England, UK is beset with lengthy waiting lists, issues with geographical inaccessibility, a lack of relevant clinical knowledge, and a failure to recognise the value of family expertise. Family doctors provide contraceptive hormones in lieu of proper access to puberty blocking or gender affirming hormones, and most families resort to private care they can ill afford. Discussion: Training in gender identity and gender dysphoria is recommended for both family doctors, and children’s mental health services. Gender identity development services could be decentralised, with local hubs offering more accessible support

    Adiposity has differing associations with incident coronary heart disease and mortality in the Scottish population: cross-sectional surveys with follow-up

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    Objective: Investigation of the association of excess adiposity with three different outcomes: all-cause mortality, coronary heart disease (CHD) mortality and incident CHD. Design: Cross-sectional surveys linked to hospital admissions and death records. Subjects: 19 329 adults (aged 18–86 years) from a representative sample of the Scottish population. Measurements: Gender-stratified Cox proportional hazards models were used to estimate hazard ratios (HRs) for all-cause mortality, CHD mortality and incident CHD. Separate models incorporating the anthropometric measurements body mass index (BMI), waist circumference (WC) or waist–hip ratio (WHR) were created adjusted for age, year of survey, smoking status and alcohol consumption. Results: For both genders, BMI-defined obesity (greater than or equal to30 kg m−2) was not associated with either an increased risk of all-cause mortality or CHD mortality. However, there was an increased risk of incident CHD among the obese men (hazard ratio (HR)=1.78; 95% confidence interval=1.37–2.31) and obese women (HR=1.93; 95% confidence interval=1.44–2.59). There was a similar pattern for WC with regard to the three outcomes; for incident CHD, the HR=1.70 (1.35–2.14) for men and 1.71 (1.28–2.29) for women in the highest WC category (men greater than or equal to102 cm, women greater than or equal to88 cm), synonymous with abdominal obesity. For men, the highest category of WHR (greater than or equal to1.0) was associated with an increased risk of all-cause mortality (1.29; 1.04–1.60) and incident CHD (1.55; 1.19–2.01). Among women with a high WHR (greater than or equal to0.85) there was an increased risk of all outcomes: all-cause mortality (1.56; 1.26–1.94), CHD mortality (2.49; 1.36–4.56) and incident CHD (1.76; 1.31–2.38). Conclusions: In this study excess adiposity was associated with an increased risk of incident CHD but not necessarily death. One possibility is that modern medical intervention has contributed to improved survival of first CHD events. The future health burden of increased obesity levels may manifest as an increase in the prevalence of individuals living with CHD and its consequences

    Rationally designed probe for reversible sensing of zinc and application in cells

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    Biologically compatible fluorescent ion sensors, particularly those that are reversible, represent a key tool for answering a range of fundamental biological questions. We report a rationally designed probe with a 6′-fluoro spiropyran scaffold (5) for the reversible sensing of zinc (Zn2+) in cells. The 6′-fluoro substituent overcomes several limitations normally associated with spiropyran-based sensors to provide an improved signal-to-background ratio and faster photoswitching times in aqueous solution. In vitro studies were performed with 5 and the 6′-nitro analogues (6) in HEK 293 and endothelial cells. The new spiropyran (5) can detect exogenous Zn2+ inside both cell types and without affecting the proliferation of endothelial cells. Studies were also performed on dying HEK 293 cells, with results demonstrating the ability of the key compound to detect endogenous Zn2+ efflux from cells undergoing apoptosis. Biocompatibility and photoswitching of 5 were demonstrated within endothelial cells but not with 6, suggesting the future applicability of sensor 5 to study intracellular Zn2+ efflux in these systems.Sabrina Heng, Philipp Reineck, Achini K. Vidanapathirana, Benjamin J. Pullen, Daniel W. Drumm, Lesley J. Ritter, Nisha Schwarz, Claudine S. Bonder, Peter J. Psaltis, Jeremy G. Thompson, Brant C. Gibson, Stephen J. Nicholls, and Andrew D. Abel

    UPDATE OF THE EUROTOP MANUAL: NEW INSIGHTS ON WAVE OVERTOPPING

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    Quite some new insights on wave overtopping were achieved since the first submission of the EurOtop Manual in 2007, which have now resulted in a second edition of this Manual. A major improvement has been made on the understanding of wave by wave overtopping and tolerable wave overtopping that is connected to it. Many videos are available on the overtopping website that show all kind of overtopping discharges and volumes and may give guidance for the user of the Manual. The EurOtop Neural Network and the EurOtop database are improved and extended versions of the earlier NN and CLASH database. New insights and prediction formulae have been developed for very low freeboards; for very steep slopes up to vertical walls; for run-up on steep slopes; for overtopping on storm walls on a promenade; and for overtopping on vertical walls, where overtopping has been divided in situations with and without an influencing foreshore and where the first situation may be divided in non-impulsive and impulsive overtopping
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