53 research outputs found

    A prospective cohort study of human papillomavirus-driven oropharyngeal cancers: implications for prognosis and immunisation

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    Aims: Oropharyngeal cancer (OPC) is increasing on a global scale, including the component driven by high-risk human papillomavirus (HR-HPV); contemporary data that provides insight into the prognosis of this disease in addition to the fraction attributable to HR-HPV are essential to inform primary and secondary disease management strategies. Materials and methods: A population-based cohort of 235 patients diagnosed with OPC between 2013 and 2015 in Scotland was assessed for HPV status using molecular genotyping. Associations between HR-HPV status and key clinical and demographic variables were estimated using the Pearson chi-squared test. Rates of overall survival and progression-free survival were estimated and visualised using Kaplan–Meier curves. Results: HPV DNA (largely HPV 16) was identified in 60% of cases. After adjustment for age, gender, deprivation, smoking, alcohol consumption and tumour stage, patients with HR-HPV-positive OPC had an 89% reduction in the risk of death (hazard ratio = 0.11, 95% confidence interval 0.05–0.25) and an 85% reduction in the risk of disease progression (hazard ratio = 0.15, 95% confidence interval 0.07–0.30). HPV positivity was not associated with age, deprivation or smoking status, whereas those who reported excess alcohol consumption were less likely to be positive for HR-HPV. Conclusions: The prevalence of HR-HPV-associated OPC is high in Scotland and strongly associated with dramatically improved clinical outcomes, including survival. Demographic/behavioural variables did not reliably predict HPV positivity in this cohort, which underlines the importance of laboratory confirmation. Finally, the dominance of HPV 16 in OPC indicates the significant impact of prophylactic immunisation on this disease

    Superfluidity vs Bose-Einstein condensation in a Bose gas with disorder

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    We investigate the phenomenon of Bose-Einstein condensation and superfluidity in a Bose gas at zero temperature with disorder. By using the Diffusion Monte-Carlo method we calculate the superfluid and the condensate fraction of the system as a function of density and strength of disorder. In the regime of weak disorder we find agreement with the analytical results obtained within the Bogoliubov model. For strong disorder the system enters an unusual regime where the superfluid fraction is smaller than the condensate fraction.Comment: 4 pages, 4 Postscript figure

    Grey matter abnormalties in first episode schizophrenia and affective psychosis

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    Background: Grey matter and other structural brain abnormalities are consistently reported in first-onset schizophrenia, but less is known about the extent of neuroanatomical changes in first-onset affective psychosis. Aims: To determine which brain abnormalities are specific to (a) schizophrenia and (b) affective psychosis. Method: We obtained dual-echo (proton density/T2-weighted) MR images and carried out voxel-based analysis on the images of 73 first-episode psychosis patients (schizophrenia=44, affective psychosis=29) and 58 healthy controls. Results: Both patients with schizophrenia and patients with affective psychosis had enlarged lateral and third ventricle volumes. Regional cortical grey matter reductions (including bilateral anterior cingulate gyrus, left insula and left fusiform gyrus) were evident in affective psychosis but not in schizophrenia, although patients with schizophrenia displayed decreased hippocampal grey matter and increased striatal grey matter at a more liberal statistical threshold. Conclusions: Both schizophrenia and affective psychosis are associated with volumetric abnormalities at the onset of frank psychosis, with some of these evident in common brain areas

    Phase Diagram of Bosonic Atoms in Two-Color Superlattices

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    We investigate the zero temperature phase diagram of a gas of bosonic atoms in one- and two-color standing-wave lattices in the framework of the Bose-Hubbard model. We first introduce some relevant physical quantities; superfluid fraction, condensate fraction, quasimomentum distribution, and matter-wave interference pattern. We then discuss the relationships between them on the formal level and show that the superfluid fraction, which is the relevant order parameter for the superfluid to Mott-insulator transition, cannot be probed directly via the matter wave interference patterns. The formal considerations are supported by exact numerical solutions of the Bose-Hubbard model for uniform one-dimensional systems. We then map out the phase diagram of bosons in non-uniform lattices. The emphasis is on optical two-color superlattices which exhibit a sinusoidal modulation of the well depth and can be easily realized experimentally. From the study of the superfluid fraction, the energy gap, and other quantities we identify new zero-temperature phases, including a localized and a quasi Bose-glass phase, and discuss prospects for their experimental observation.Comment: 18 pages, 17 figures, using REVTEX

    Outcomes in rheumatoid arthritis patients treated with abatacept : a UK multi-centre observational study

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    Background Rheumatoid arthritis (RA) is an inflammatory autoimmune disease that causes chronic synovitis, resulting in progressive joint destruction and functional disability and affects approximately 400,000 people in the UK. This real-world study aimed to describe the characteristics, treatment patterns and clinical outcomes of patients who received abatacept in UK clinical practice. Methods This was a multi-centre, retrospective, observational study of patients with RA treated with abatacept at four UK centres between 01 January 2013 and 31 December 2017. Data were collected from medical records of each patient from the index date (date of first bDMARD initiation) until the most recent visit, death or end of study (31 December 2017). Results In total, 213 patients were included in the study. Patients received up to eight lines of therapy (LOTs). Treatment with abatacept, or any other bDMARD, was associated with reductions in DAS28-ESR and DAS28-CRP scores at 6 and 12 months. The distribution of EULAR responses (good/moderate/no response) tended to be more favourable for patients when receiving abatacept than when receiving other bDMARDs (22.8%/41.3%/35.9% versus 16.6%/41.4%/42.1% at 6 months, and 27.9%/36.1%/36.1% versus 21.2%/34.5%/44.2% at 12 months). Patients receiving abatacept at LOT1 (n = 68) spent significantly longer on treatment compared with patients receiving other bDMARDs (53.4 vs. 17.4 months; p< 0.01); a similar trend was observed for LOT2. Among patients who discontinued after 6 months, a greater proportion experienced infection requiring antibiotics when receiving other bDMARDs compared to those receiving abatacept. Conclusions RA patients who received bDMARDs, including abatacept, experienced reduced disease activity. When receiving abatacept as first or second line of therapy, patients persisted with treatment significantly longer than those receiving other bDMARDs

    Nature of the quantum phase transitions in the two-dimensional hardcore boson model

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    We use two Quantum Monte Carlo algorithms to map out the phase diagram of the two-dimensional hardcore boson Hubbard model with near (V1V_1) and next near (V2V_2) neighbor repulsion. At half filling we find three phases: Superfluid (SF), checkerboard solid and striped solid depending on the relative values of V1V_1, V2V_2 and the kinetic energy. Doping away from half filling, the checkerboard solid undergoes phase separation: The superfluid and solid phases co-exist but not as a single thermodynamic phase. As a function of doping, the transition from the checkerboard solid is therefore first order. In contrast, doping the striped solid away from half filling instead produces a striped supersolid phase: Co-existence of density order with superfluidity as a single phase. One surprising result is that the entire line of transitions between the SF and checkerboard solid phases at half filling appears to exhibit dynamical O(3) symmetry restoration. The transitions appear to be in the same universality class as the special Heisenberg point even though this symmetry is explicitly broken by the V2V_2 interaction.Comment: 10 pages, 14 eps figures, include

    The Weak Charge of the Proton and New Physics

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    We address the physics implications of a precision determination of the weak charge of the proton, QWP, from a parity violating elastic electron proton scattering experiment to be performed at the Jefferson Laboratory. We present the Standard Model (SM) expression for QWP including one-loop radiative corrections, and discuss in detail the theoretical uncertainties and missing higher order QCD corrections. Owing to a fortuitous cancellation, the value of QWP is suppressed in the SM, making it a unique place to look for physics beyond the SM. Examples include extra neutral gauge bosons, supersymmetry, and leptoquarks. We argue that a QWP measurement will provide an important complement to both high energy collider experiments and other low energy electroweak measurements. The anticipated experimental precision requires the knowledge of the order alpha_s corrections to the pure electroweak box contributions. We compute these contributions for QWP, as well as for the weak charges of heavy elements as determined from atomic parity violation.Comment: 22 pages of LaTeX, 5 figure
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