598 research outputs found

    Fuels from tyres by pyrolysis in molten salts

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    The current annual arisings of used car/van tyres in the U.K. has been found to be around 25m (188,000 tonnes). After the established reuse industries have taken their requirements this leaves 13.5m (102,000 tonnes) waste tyres; a quantity that can no longer be satisfactorily tipped. Laboratory scale experiments have shown that tyre can be pyrolised, using a molten carbonate system as the reaction medium, at rates corresponding to 14.9-42.7 g tyre/min. per litre of melt over the range 475 and 650°C. The product yields by weight of tyre input between the same temperatures are: hydrocarbon oil 23-36 wt. %, hydrocarbon gas 7- 18 wt. %, carbonaceous char 35-40 wt. %, steel 16.7 wt. % and inorganics 5.4 wt. %. The oil and gas evolve from the reactor and can easily be collected by conventional means. The steel and inorganics remain in the reactor although on the commercial scale it is proposed that they would be removed by physical and chemical methods respectively. The char was found to pose considerable handling problems and so a method was devised by which it could be gasified in the reactor. This was best achieved by passing air at a less than stoichiometric rate which gave a gaseous product rich in carbon monoxide. In addition this action provides heat for the system as a whole. The rates at 675-9000C were in the range corresponding to 5.6- 14.89 char/min. per litre of melt. A process flow chart has been proposed for a continuous operation based on these systems. Data from theoretical and experimental studies has enabled economic evaluations of several commercial scales to be carried out. These have shown that 4,000 and 10,000 t/yr operations show a DCF rate of return around 30% while a 50,000 t/yr operation shows 60% which would be attractive to an experienced scrap operator

    Reconstructing 3D x-ray CT images of polymer gel dosimeters using the zero-scan method

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    In this study x-ray CT has been used to produce a 3D image of an irradiated PAGAT gel sample, with noise-reduction achieved using the ‘zero-scan’ method. The gel was repeatedly CT scanned and a linear fit to the varying Hounsfield unit of each pixel in the 3D volume was evaluated across the repeated scans, allowing a zero-scan extrapolation of the image to be obtained. To minimise heating of the CT scanner’s x-ray tube, this study used a large slice thickness (1 cm), to provide image slices across the irradiated region of the gel, and a relatively small number of CT scans (63), to extrapolate the zero-scan image. The resulting set of transverse images shows reduced noise compared to images from the initial CT scan of the gel, without being degraded by the additional radiation dose delivered to the gel during the repeated scanning. The full, 3D image of the gel has a low spatial resolution in the longitudinal direction, due to the selected scan parameters. Nonetheless, important features of the dose distribution are apparent in the 3D x-ray CT scan of the gel. The results of this study demonstrate that the zero-scan extrapolation method can be applied to the reconstruction of multiple x-ray CT slices, to provide useful 2D and 3D images of irradiated dosimetry gels

    Quantitative evaluation of polymer gel dosimeters by broadband ultrasound attenuation

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    Ultrasound has been examined previously as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose response to ultrasound transmission measurements. In this current work we extend previous work to measure the broadband ultrasound attenuation (BUA) response of irradiated PAGAT gel dosimeters, using a novel ultrasound computed tomography system

    The treatment of nephrotic syndrome caused by primary (light chain) amyloid with vincristine, doxorubicin and dexamethasone.

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    Three out of four patients with primary (light chain) amyloid nephrotic syndrome treated with vincristine, doxorubicin and dexamethasone (VAD) induction obtained a partial response and are alive in continuing remission at 4.1, 6.5 and 9.3 years. These preliminary results are of considerable interest and suggest that prospective evaluation of this regimen is warranted in patients with this condition

    How does reviewing the evidence change veterinary surgeons' beliefs regarding the treatment of ovine footrot? A quantitative and qualitative study

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    Footrot is a widespread, infectious cause of lameness in sheep, with major economic and welfare costs. The aims of this research were: (i) to quantify how veterinary surgeons’ beliefs regarding the efficacy of two treatments for footrot changed following a review of the evidence (ii) to obtain a consensus opinion following group discussions (iii) to capture complementary qualitative data to place their beliefs within a broader clinical context. Grounded in a Bayesian statistical framework, probabilistic elicitation (roulette method) was used to quantify the beliefs of eleven veterinary surgeons during two one-day workshops. There was considerable heterogeneity in veterinary surgeons’ beliefs before they listened to a review of the evidence. After hearing the evidence, seven participants quantifiably changed their beliefs. In particular, two participants who initially believed that foot trimming with topical oxytetracycline was the better treatment, changed to entirely favour systemic and topical oxytetracycline instead. The results suggest that a substantial amount of the variation in beliefs related to differences in veterinary surgeons’ knowledge of the evidence. Although considerable differences in opinion still remained after the evidence review, with several participants having non-overlapping 95% credible intervals, both groups did achieve a consensus opinion. Two key findings from the qualitative data were: (i) veterinary surgeons believed that farmers are unlikely to actively seek advice on lameness, suggesting a proactive veterinary approach is required (ii) more attention could be given to improving the way in which veterinary advice is delivered to farmers. In summary this study has: (i) demonstrated a practical method for probabilistically quantifying how veterinary surgeons’ beliefs change (ii) revealed that the evidence that currently exists is capable of changing veterinary opinion (iii) suggested that improved transfer of research knowledge into veterinary practice is needed (iv) identified some potential obstacles to the implementation of veterinary advice by farmers

    Safety and efficacy of fluticasone propionate in the topical treatment of skin diseases

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    Fluticasone propionate - the first carbothioate corticosteroid - has been classified as a potent anti-inflammatory drug for dermatological use. It is available as 0.05% cream and 0.005% ointment formulations for the acute and maintenance treatment of patients with dermatological disorders such as atopic dermatitis, psoriasis and vitiligo. This glucocorticoid is characterized by high lipophilicity, high glucocorticoid receptor binding and activation, and a rapid metabolic turnover in skin. Although skin blanching following fluticasone propionate exceeds that of corticosteroids of medium strength, several clinical trials demonstrate a low potential for cutaneous and systemic side-effects, even in difficult-to-treat areas like the face, the eyelids and intertriginous areas. Even among paediatric patients with atopic dermatitis, fluticasone propionate proved to be safe and effective. These pharmacological and clinical properties are reflected by the high therapeutic index of this glucocorticoid

    Understanding the impact of ‘wish-granting’ interventions on the health and wellbeing of children with life-threatening health conditions and their families: A systematic review

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    This is an accepted manuscript of an article published by SAGE in Journal of Child Health Care on 8 May 2021. The accepted version of the publication may differ from the final published version.This review aimed to explore how wish-granting interventions impact on the health and wellbeing of children with life-threatening health conditions and their families, using any study design. Six electronic databases (Medline; PsycINFO; CINAHL; Embase; AMED; HMIC) were systematically searched to identify eligible research articles. Studies were critically appraised using a Mixed Methods Appraisal Tool. Findings were synthesised narratively. Ten papers were included, reporting studies conducted across five countries, published from 2007-2019. Study designs were diverse (four quantitative; two qualitative; four mixed method). Results indicated improvements to physical and mental health, quality of life, social wellbeing, resilience and coping for wish children, parents and siblings. In conclusion, wish-granting interventions can positively impact health and therefore, should not be discouraged; however, more research is needed to define and quantify the impact of wish-fulfillment and to understand how it can be maximized

    Cannabis and harm minimisation drug education: Findings from the Drug Education in Victorian Schools study

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    Aims: To evaluate the effectiveness of an integrated harm minimisation focused school drug education programme in terms of reducing cannabis use and harm. Design and Methods: A cluster randomised controlled trial of the 18 lesson Drug Education in Victorian Schools (DEVS) drug education programme was undertaken with students during years eight and nine (13 and 14 years of age respectively), with follow up in year ten (15 years of age). The programme covered all drugs, employed a harm minimisation approach that used participatory, critical thinking and skills based teaching methods, and engaged parental influence through home activities. Twenty-one secondary schools in Victoria, Australia, were randomly allocated to receive the DEVS programme (14 schools) or the drug education usually provided by their schools (7 schools). In relation to cannabis, communication with parents, lessons remembered, responsible attitudes, whether used, frequency of use and associated harms were measured. Results: In comparison to controls, there was a significantly greater increase in the intervention students’ communication with parents about cannabis recall of cannabis lessons received, and responsible attitudes towards cannabis. While there were no significant differences between the two study groups in relation to the proportion of cannabis users, the increase in level of use by intervention students was significantly less and they experienced a lesser increase in associated harms. Conclusion: A harm minimisation focused school drug education programme reduced the level of cannabis use and associated harm. This supports harm minimisation education as an effective prevention strategy for school students
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