Abstract Objectives The aim of this study was to investigate the differences in main characteristics, reporting and methodological quality between爌rospectively registered and nonregistered systematic reviews. Study Design and Setting PubMed was searched to identify systematic reviews of randomized controlled trials published in 2015 in English. After title and abstract screening, potentially relevant reviews were divided into three groups: registered non-Cochrane reviews, Cochrane reviews, and nonregistered reviews. For each group, random number tables were generated in Microsoft Excel, and the first 50 eligible studies from each group were randomly selected. Data of interest from systematic reviews were extracted. Regression analyses were conducted to explore the association between total Revised Assessment of Multiple Systematic Review (R-AMSTAR) or Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) scores and the selected characteristics of systematic reviews. Results The conducting and reporting of literature search in registered reviews were superior to nonregistered reviews. Differences in 9 of the 11 R-AMSTAR items were statistically significant between registered and nonregistered reviews. The total R-AMSTAR score of registered reviews was higher than nonregistered reviews [mean difference (MD)??.82, 95% confidence interval (CI): 3.70, 5.94]. Sensitivity analysis by excluding the registration-related item presented similar result (MD??.34, 95% CI: 3.28, 5.40). Total PRISMA scores of registered reviews were significantly higher than nonregistered reviews (all reviews: MD??.47, 95% CI: 0.64-2.30; non-Cochrane reviews: MD??.49, 95% CI: 0.56-2.42). However, the difference in the total PRISMA score was no longer statistically significant after excluding the item related to registration (item 5). Regression analyses showed similar results. Conclusion Prospective registration may at least indirectly improve the overall methodological quality of systematic reviews, although its impact on the overall reporting quality was not significant.
Methane (CH4) is the main component of natural gas and produces less carbon dioxide for each unit of heat released and more heat per unit mass than other hydrocarbon fuels, and it is thus considered to be an environmental-friendly fuel. The explosion and detonation hazards associated with methane mixtures deserve special attention because of their potential safety hazards. Acoustically absorbing materials are effective in damping out the transverse wave of a detonation structure. A detonation could be attenuated or prohibited after passing over this material, but the failure mechanism of the detonation still needs further exploration. In this study, tubes made of an acoustically absorbing material (hole diameters of the wall are from 30 mu m to 300 mu m) are inserted in the smooth rigid wall tube to investigate the effect of the porous-walled material on the detonation propagation at the near-limit conditions. Porous-walled tubes with three different scales (L/D = 3.85, 7.69, and 15.38) are studied. Photodiodes and smoked foils are employed to simultaneously measure the local velocity of the combustion waves and record the cellular detonation structures, respectively. The results show that, for shorter porous-walled tubes, the prohibition effect of the absorbing material on the detonation propagation is only prominent at the critical and sub-critical conditions, but the material has a minor effect on the detonation propagation at the super-critical condition. In addition, the prohibition effect of the porous material on the detonation propagation becomes more evident with the increased length of the acoustically absorbing material. This outcome occurs because a transverse wave plays an important role in the propagation of a self-sustained detonation, as it is partially damped during the transmission of the detonation through the porous-walled tube; thus, extending the length of the porous-walled section results in increasing the losses of the incident and reflected shock waves due to a greater expansion and mass divergence into porous material. Therefore, the velocity of the combustion wave decreases faster in the downstream of the porous material with an increased length. On the other hand, the methane-oxygen mixture has a highly irregular cellular pattern and is characterized as an unstable mixture with a high degree of instability. The strong instability leads to an enhanced ability to generate new transverse waves in the far downstream, and therefore, at the super-critical condition (a relatively higher initial pressure), the instability partly compensates for the negative effect of the acoustically absorbing material on the detonation propagation.
Lauren Mizock;Julie Riley;Nelly Yuen;T. Dawson Woodrum;Erica A. Sotilleo;Alayne J. Ormerod
来源期刊：Stigma and health.
年/卷/期：2018 / 3 / 3
Transgender individuals report frequent encounters with transphobia in the workplace, although relatively few studies have investigated this phenomenon. The present grounded theory analysis was conducted with 45 transgender and gender diverse participants to delineate their different experiences with bias and discrimination in the workplace. Qualitative data analysis revealed the following themes pertaining to work transphobia: lack of social support, workplace gender policing, personal safety threats, acquisition and advancement barriers, intersectional discrimination, intuited stigma, and lack of inclusive policy. Results suggest the diverse challenges faced by transgender individuals in the workplace and the need for further interventions, supports, and policy to counteract work-related transphobia.
Lu, J. Z.;Cao, J.;Lu, H. F.;Zhang, L. Y.;Luo, K. Y.
来源期刊：Surface & Coatings Technology
Microhardness, wear properties and microstructure of Fe -based coatings with various WC contents on H13 hot working die steel by laser cladding were investigated. Special attention was paid to the effects of various WC contents on the microstructural characterization and wear properties of different coatings by means of optical microscopy (OM) and scanning electron microscopy (SEM). Results indicated that only a small part of the periphery of the WC in the WC -added coatings was melted, and the un-melted WC particles in the coatings acted as a hard reinforcement. Besides, the microhardness in the cladding layer increased with the increment of the mass fraction of WC particles, and presented a gradient distribution along in-depth direction of the coatings. Furthermore, the Fe -based clad coating with WC particles exhibited a higher wear resistance and a lower friction coefficient compared with the substrate and Fe -based clad coating. In addition, the influence mechanism of WC particles on microstructural evolution and wear resistance was also discussed.