373 research outputs found

    The effect of increased microporosity on bone formation within silicate-substituted scaffolds in an ovine posterolateral spinal fusion model

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    This study compared the bone forming capacity of the same formulation of silicate-substituted bone graft substitute materials with different microporosity in an instrumented posterolateral spinal fusion ovine model. Materials with a strut porosity of (i) 22.5% (SiCaP) or (ii) 36.0% (SiCaP(+)) were packed along either side of the spine. Bone apposition rates, % new bone formation, % bone-implant contact, and % graft resorption were quantified at 8, 12, and 24 weeks post surgery. Computed Tomography (CT) was used to grade the formation of fusion bridges between vertebrae. Results showed no significant difference in bone apposition rates, % new bone formation, and % bone-implant contact when the two materials were compared. However, at 8 weeks, a significantly higher CT score was obtained in the SiCaP(+) group (0.83±0.17) when compared with the SiCaP group (0.17±0.17; p=0.027). Significantly less scaffold remained in the SiCaP(+) group at 12 weeks (p=0.018). Both SiCaP and SiCaP(+) formulations augmented bone formation. Increasing the strut porosity did not significantly increase bone formation however, at 8 weeks it promoted the formation of more highly mineralized bone resulting in a significantly higher CT score, suggesting the bone tissue formed was more mature

    The effect of particle size on the osteointegration of injectable silicate-substituted calcium phosphate bone substitute materials.

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    Calcium phosphate (CaP) particles as a carrier in an injectable bone filler allows less invasive treatment of bony defects. The effect of changing granule size within a poloxamer filler on the osteointegration of silicate-substituted calcium phosphate (SiCaP) bone substitute materials was investigated in an ovine critical-sized femoral condyle defect model. Treatment group (TG) 1 consisted of SiCaP granules sized 1000-2000 μm in diameter (100 vol %). TG2 investigated a granule size of 250-500 μm (75 vol %), TG3 a granule size of 90-125 μm (75 vol %) and TG4 a granule size of 90-125 μm (50 vol %). Following a 4 and 8 week in vivo period, bone area, bone-implant contact, and remaining implant area were quantified within each defect. At 4 weeks, significantly increased bone formation was measured in TG2 (13.32% ± 1.38%) when compared with all other groups (p = 0.021 in all cases). Bone in contact with the bone substitute surface was also significantly higher in TG2. At 8 weeks most new bone was associated within defects containing the smallest granule size investigated (at the lower volume) (TG4) (42.78 ± 3.36%) however this group was also associated with higher amounts of fragmented SiCaP. These smaller particles were phagocytosed by macrophages and did not appear to have a negative influence on healing. In conclusion, SiCaP granules of 250-500 μm in size may be a more suitable scaffold when used as an injectable bone filler and may be a convenient method for treating bony defects

    The effectiveness of tobacco control television advertisements in increasing the prevalence of smoke-free homes

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    BACKGROUND: There is considerable evidence that tobacco control mass media campaigns can change smoking behaviour. In the UK, campaigns over the last decade have contributed to declines in smoking prevalence and been associated with falls in cigarette consumption among continuing smokers. However, it is less evident whether such campaigns can also play a role in changing smokers’ behaviour in relation to protecting others from the harmful effects of their smoking in the home. We investigated whether exposure to English televised tobacco control campaigns, and specifically campaigns targeting second hand smoking, is associated with smokers having a smoke-free home. METHODS: We used repeated cross-sectional national survey data on 9872 households which participated in the Health Survey for England between 2004 and 2010, with at least one adult current smoker living in the household. Exposure to all government-funded televised tobacco control campaigns, and to those specifically with a second hand smoking theme, was quantified in Gross Rating Points (GRPs), an average per capita measure of advert exposure where 100 GRPs indicates 100 % of adults exposed once or 50 % twice. Our outcome was self-reported presence of a smoke-free home (where no one smokes in the home on most days). Analysis used generalised additive models, controlling for individual factors and temporal trends. RESULTS: There was no association between monthly televised campaigns overall and the probability of having a smoke-free home. However, exposure to campaigns specifically targeting second hand smoke was associated with increased odds of a smoke-free home in the following month (odds ratio per additional 100 GRPs, 1.07, 95 % CI 1.01 to 1.13), though this association was not seen at other lags. These effects were not modified by socio-economic status or by presence of a child in the home. CONCLUSIONS: Our findings provide tentative evidence that mass media campaigns specifically focussing on second hand smoke may be effective in reducing smoking in the home, and further evaluation of campaigns of this type is needed. General tobacco control campaigns in England, which largely focus on promoting smoking cessation, do not impact on smoke-free homes over and above their direct effect at reducing smoking

    Hydrothermal alteration of andesitic lava domes can lead to explosive volcanic behaviour

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    Dome-forming volcanoes are among the most hazardous volcanoes on Earth. Magmatic outgassing can be hindered if the permeability of a lava dome is reduced, promoting pore pressure augmentation and explosive behaviour. Laboratory data show that acid-sulphate alteration, common to volcanoes worldwide, can reduce the permeability on the sample lengthscale by up to four orders of magnitude and is the result of pore- and microfracture-filling mineral precipitation. Calculations using these data demonstrate that intense alteration can reduce the equivalent permeability of a dome by two orders of magnitude, which we show using numerical modelling to be sufficient to increase pore pressure. The fragmentation criterion shows that the predicted pore pressure increase is capable of fragmenting the majority of dome-forming materials, thus promoting explosive volcanism. It is crucial that hydrothermal alteration, which develops over months to years, is monitored at dome-forming volcanoes and is incorporated into real-time hazard assessments

    The UK Pharmacy Care Plan service: Description, recruitment and initial views on a new community pharmacy intervention

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    Introduction: The UK government advocates person-centred healthcare which is ideal for supporting patients to make appropriate lifestyle choices and to address non-adherence. The Community Pharmacy Future group, a collaboration between community pharmacy companies and independents in the UK, introduced a person-centred service for patients with multiple long-term conditions in 50 pharmacies in Northern England. Objective: Describe the initial findings from the set up and delivery of a novel community pharmacy-based person-centred service. Method: Patients over fifty years of age prescribed more than one medicine including at least one for cardiovascular disease or diabetes were enrolled. Medication review and person-centred consultation resulted in agreed health goals and steps towards achieving them. Data were collated and analysed to determine appropriateness of patient recruitment process and quality of outcome data collection. A focus group of seven pharmacists was used to ascertain initial views on the service. Results: Within 3 months of service initiation, 683 patients had baseline clinical data recorded, of which 86.9% were overweight or obese, 53.7% had hypertension and 80.8% had high cardiovascular risk. 544 (77.2%) patients set at least one goal during the first consultation with 120 (22.1%) setting multiple goals. A majority of patients identified their goals as improvement in condition, activity or quality of life. Pharmacists could see the potential patient benefit and the extended role opportunities the service provided. Allowing patients to set their own goals occasionally identified gaps to be addressed in pharmacist knowledge. Conclusion: Pharmacists successfully recruited a large number of patients who were appropriate for such a service. Patients were willing to identify goals with the pharmacist, the majority of which, if met, may result in improvements in quality of life. While challenges in delivery were acknowledged, allowing patients to identify their own personalised goals was seen as a positive approach to providing patient services

    Current polarity-dependent manipulation of antiferromagnetic domains

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    Antiferromagnets have several favourable properties as active elements in spintronic devices, including ultra-fast dynamics, zero stray fields and insensitivity to external magnetic fields. Tetragonal CuMnAs is a testbed system in which the antiferromagnetic order parameter can be switched reversibly at ambient conditions using electrical currents. In previous experiments, orthogonal in-plane current pulses were used to induce 90° rotations of antiferromagnetic domains and demonstrate the operation of all-electrical memory bits in a multi-terminal geometry. Here, we demonstrate that antiferromagnetic domain walls can be manipulated to realize stable and reproducible domain changes using only two electrical contacts. This is achieved by using the polarity of the current to switch the sign of the current-induced effective field acting on the antiferromagnetic sublattices. The resulting reversible domain and domain wall reconfigurations are imaged using X-ray magnetic linear dichroism microscopy, and can also be detected electrically. Switching by domain-wall motion can occur at much lower current densities than those needed for coherent domain switching

    Gaia Gral: Gaia Dr2 Gravitational Lens Systems. Vi. Spectroscopic Confirmation And Modeling Of Quadruply Imaged Lensed Quasars

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    Combining the exquisite angular resolution of Gaia with optical light curves and WISE photometry, the Gaia Gravitational Lenses group (GraL) uses machine-learning techniques to identify candidate strongly lensed quasars, and has confirmed over two dozen new strongly lensed quasars from the Gaia Data Release 2. This paper reports on the 12 quadruply imaged quasars identified by this effort to date, which is a similar to 20% increase in the total number of confirmed quadruply imaged quasars. We discuss the candidate selection, spectroscopic follow-up, and lens modeling. We also report our spectroscopic failures as an aid for future investigations

    Der Einfluss der Kapazitätsgröße und -auslastung auf den Kostenverlauf ausgewählter Hilfskostenstellen von Molkereien - Abteilung Dampfversorgung

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    Die Kostenanalyse zur Bestimmung des Einflusses der Kapazitätsgröße und -auslastung auf den Kostenverlauf von Hilfskostenstellen (Hilfsabteilungen) erfolgt mit Hilfe von Modellkalkulationen. Eine spezielle Form der Teilkostenrechnung ermöglicht die Zurechnung der Kosten nach Kostenkategorien (jahresfix, tagesfix, ggf. chargenfix und mengenproportional) auf die entsprechenden Kostenträger (z. B. Kälte, Dampf) der jeweiligen Hilfskostenstelle. Durch computergestützte Simulationen können die Auswirkungen der verschiedenen Kosteneinflußfaktoren im einzelnen quantifiziert werden
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