46 research outputs found

    Randomised, double-blind, placebo-controlled trials of non-individualised homeopathic treatment: systematic review and meta-analysis

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    Background: A rigorous systematic review and meta-analysis focused on randomised controlled trials (RCTs) of non-individualised homeopathic treatment has not previously been reported. We tested the null hypothesis that the main outcome of treatment using a non-individualised (standardised) homeopathic medicine is indistinguishable from that of placebo. An additional aim was to quantify any condition-specific effects of non-individualised homeopathic treatment. Methods: Literature search strategy, data extraction and statistical analysis all followed the methods described in a pre-published protocol. A trial comprised ‘reliable evidence’ if its risk of bias was low or it was unclear in one specified domain of assessment. ‘Effect size’ was reported as standardised mean difference (SMD), with arithmetic transformation for dichotomous data carried out as required; a negative SMD indicated an effect favouring homeopathy. Results: Forty-eight different clinical conditions were represented in 75 eligible RCTs. Forty-nine trials were classed as ‘high risk of bias’ and 23 as ‘uncertain risk of bias’; the remaining three, clinically heterogeneous, trials displayed sufficiently low risk of bias to be designated reliable evidence. Fifty-four trials had extractable data: pooled SMD was –0.33 (95% confidence interval (CI) –0.44, –0.21), which was attenuated to –0.16 (95% CI –0.31, –0.02) after adjustment for publication bias. The three trials with reliable evidence yielded a non-significant pooled SMD: –0.18 (95% CI –0.46, 0.09). There was no single clinical condition for which meta-analysis included reliable evidence. Conclusions: The quality of the body of evidence is low. A meta-analysis of all extractable data leads to rejection of our null hypothesis, but analysis of a small sub-group of reliable evidence does not support that rejection. Reliable evidence is lacking in condition-specific meta-analyses, precluding relevant conclusions. Better designed and more rigorous RCTs are needed in order to develop an evidence base that can decisively provide reliable effect estimates of non-individualised homeopathic treatment

    Dynamic mechanical behaviour of polyethylene

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    Dynamic compressive curves of high density semi-crystalline polyethylene, PEHD, were obtained via the Split Hopkinson Pressure Bar, SHPB, technique. The SHPB was fitted with polymeric bars, PMMA, to avoid a large impedance mismatch between the specimens and the bars. As a consequence, attenuation and dispersion had to be taken into account. Care was also exercised with frictional effects by using ring specimens instead of flat disks. Ring specimens have the additional advantage of yielding a more constant strain rate in the tests. The results clearly show a very strain rate sensitive material, a feature which should be taken into consideration when analysing PEHD components

    Polymer plates subjected to impact: Experimental tests and numerical simulations

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    This paper presents quasi-static and dynamic tests on circular clamped plates made of a PEHD thermoplastic. A brief review of the main results from a material test programme, involving tension and compression tests at different rates, is also provided. The results from the material tests are used to identify the coefficients of a recently proposed hyperelastic-viscoplastic constitutive model for thermoplastics, also outlined here. Finally, the model is employed in numerical simulations of the impact tests. It is shown that the model represents the force-displacement response of the experimental tests fairly well. Also, considering the quasi-static tests, a localized failure mechanism around the impactor is captured

    Wireless, fully implantable cardiac stimulation and recording with on-device computation for closed-loop pacing and defibrillation

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    Monitoring and control of cardiac function are critical for investigation of cardiovascular pathophysiology and developing life-saving therapies. However, chronic stimulation of the heart in freely moving small animal subjects, which offer a variety of genotypes and phenotypes, is currently difficult. Specifically, real-time control of cardiac function with high spatial and temporal resolution is currently not possible. Here, we introduce a wireless battery-free device with on-board computation for real-time cardiac control with multisite stimulation enabling optogenetic modulation of the entire rodent heart. Seamless integration of the biointerface with the heart is enabled by machine learning-guided design of ultrathin arrays. Long-term pacing, recording, and on-board computation are demonstrated in freely moving animals. This device class enables new heart failure models and offers a platform to test real-time therapeutic paradigms over chronic time scales by providing means to control cardiac function continuously over the lifetime of the subject.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
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