89 research outputs found

    The value of the pragmatic-explanatory continuum indicator summary wheel in an ongoing study: the bullous pemphigoid steroids and tetracyclines study

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    BACKGROUND: The Pragmatic-Explanatory Continuum Indicator Summary (PRECIS) tool is intended to be used in the design phase of trials to help investigative teams design trials in-line with their purpose. Our team applied this tool to an ongoing trial (BLISTER) to determine whether the initial suggestion among some team members that the trial could be described as largely pragmatic was the consensus. METHODS: Each of the six members of the BLISTER trial team was sent a blank PRECIS wheel to independently complete. The results obtained were averaged and plotted on a single PRECIS wheel to illustrate the degree of pragmatism of the trial. RESULTS: The trial team found that the design of the trial was closest to the pragmatic end of the pragmatic-explanatory continuum. The strongest consensus was found on the 'flexibility of the comparison intervention' and 'practitioner adherence' domains (SD = 13). The trial team appeared to disagree most on the 'eligibility criteria' (SD = 35) and 'participant compliance' (SD = 31) domains, although the large standard deviations were a result of a single outlier in the two domains. CONCLUSION: The PRECIS tool can be used to retrospectively determine the pragmatism of a trial provided enough expertise and information on the trial is available. Illustrating the design of a trial on the PRECIS wheel can help research users more easily identify studies of interest. We hope our recommendations for applying this useful tool will encourage others to consider using it when designing, conducting and reporting studies. TRIAL REGISTRATION: Current Controlled Trials http://www.controlled-trials.com/ISRCTN13704604

    The Physical Conditions for Massive Star Formation: Dust Continuum Maps and Modeling

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    Fifty-one dense cores associated with water masers were mapped at 350 micron. These cores are very luminous, 10^3 < Lbol/Lsun < 10^6, indicative of the formation of massive stars. Dust continuum contour maps and photometry are presented for these sources. The spectral energy distributions and normalized radial profiles of dust continuum emission were modeled for 31 sources using a one-dimensional dust radiative transfer code, assuming a power law density distribution in the envelope, n = n_f (r/r_f)^{-p}. The best fit density power law exponent, p, ranged from 0.75 to 2.5 with = 1.8 +/- 0.4. The mean value of p is comparable to that found in regions forming only low mass stars. The mean p is incompatible with a logatropic sphere (p = 1), but other star formation models cannot be ruled out. Different mass estimates are compared and mean masses of gas and dust are reported within a half-power radius determined from the dust emission and within a radius where the total density exceeds 10^4 cm^3. Evolutionary indicators commonly used for low mass star formation may have some utility for regions forming massive stars. For comparison with extragalactic star formation studies, the luminosity to dust mass ratio is calculated for these sources with a method most parallel to that used in studies of distant galaxies and is found to be similar to that seen in high redshift starburst galaxies.Comment: 45 pages, 20 figures, accepted to ApJ Supplemen

    How Well Do Randomized Trials Inform Decision Making: Systematic Review Using Comparative Effectiveness Research Measures on Acupuncture for Back Pain

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    Background: For Comparative Effectiveness Research (CER) there is a need to develop scales for appraisal of available clinical research. Aims were to 1) test the feasibility of applying the pragmatic-explanatory continuum indicator summary tool and the six CER defining characteristics of the Institute of Medicine to RCTs of acupuncture for treatment of low back pain, and 2) evaluate the extent to which the evidence from these RCTs is relevant to clinical and health policy decision making. Methods: We searched Medline, the AcuTrials™ Database to February 2011 and reference lists and included full-report randomized trials in English that compared needle acupuncture with a conventional treatment in adults with non-specific acute and/or chronic low back pain and restricted to those with ≥30 patients in the acupuncture group. Papers were evaluated by 5 raters. Principal Findings: From 119 abstracts, 44 full-text publications were screened and 10 trials (4,901 patients) were evaluated. Due to missing information and initial difficulties in operationalizing the scoring items, the first scoring revealed inter-rater and inter-item variance (intraclass correlations 0.02-0.60), which improved after consensus discussions to 0.20-1.00. The 10 trials were found to cover the efficacy-effectiveness continuum; those with more flexible acupuncture and no placebo control scored closer to effectiveness. Conclusion: Both instruments proved useful, but need further development. In addition, CONSORT guidelines for reporting pragmatic trials should be expanded. Most studies in this review already reflect the movement towards CER and similar approaches can be taken to evaluate comparative effectiveness relevance of RCTs for other treatments. © 2012 Witt et al.published_or_final_versio

    Diurnal Rhythms Result in Significant Changes in the Cellular Protein Complement in the Cyanobacterium Cyanothece 51142

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    Cyanothece sp. ATCC 51142 is a diazotrophic cyanobacterium notable for its ability to perform oxygenic photosynthesis and dinitrogen fixation in the same single cell. Previous transcriptional analysis revealed that the existence of these incompatible cellular processes largely depends on tightly synchronized expression programs involving ∼30% of genes in the genome. To expand upon current knowledge, we have utilized sensitive proteomic approaches to examine the impact of diurnal rhythms on the protein complement in Cyanothece 51142. We found that 250 proteins accounting for ∼5% of the predicted ORFs from the Cyanothece 51142 genome and 20% of proteins detected under alternating light/dark conditions exhibited periodic oscillations in their abundances. Our results suggest that altered enzyme activities at different phases during the diurnal cycle can be attributed to changes in the abundance of related proteins and key compounds. The integration of global proteomics and transcriptomic data further revealed that post-transcriptional events are important for temporal regulation of processes such as photosynthesis in Cyanothece 51142. This analysis is the first comprehensive report on global quantitative proteomics in a unicellular diazotrophic cyanobacterium and uncovers novel findings about diurnal rhythms

    Lattice defects in neutron irradiated αCu solid solution alloys

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    The lattice defects in neutron irradiated αCu-Al, αCu-Ga and αCu-Ge solid solution alloys have been observed by transmission electron microscopy and the defect structures are compared with neutron irradiated copper. Alloys with 0.5 at. % of either aluminium, gallium or germanium show both large resolvable dislocation loops and small ‘black spots’; the same defects are seen in irradiated copper. Alloys ≥ 5 at. % solute show only the small ‘black spots’. The effect of these higher solute alloys in suppressing the formation of the large resolvable loops has also been observed after alpha particle irradiation. Since the large loops are believed to be interstitial in nature, the results are explained on the basis of interstitial-solute atom binding. © 1966 Taylor & Francis Group, LLC
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