ObjectivesWe systematically analysed recommendations from gout guidelines as an example, to provide a basis for developing a reporting standard of recommendations in clinical practice guidelines (CPGs).DesignSystematic review without meta-analysis.MethodsWe systematically searched MEDLINE and all relevant guideline websites (National Institute for Health and Care Excellence, National Guideline Clearinghouse, Scottish Intercollegiate Guidelines Network, WHO, Guidelines International Network, DynaMed, UpTodate, Best Practice) from their inception to January 2017 to identify and select gout CPGs. We used search terms such as ‘gout’, ‘hyperuricemia’ and ‘guideline’. We included the eligible CPGs of gout according to the predefined inclusion and exclusion criteria after screening titles, abstracts and full texts. The characteristics of recommendations reported in the included guidelines were extracted and analysed.ResultsA total of 15 gout guidelines with a range of 5–80 recommendations were retrieved. Several indicators were used in the gout guidelines to facilitate identification of recommendations, including grouping all recommendations in a summary section, formatting recommendations in a particular or special way, using locating words for recommendations and indicating the strength of recommendation and quality of evidence. We found some components commonly used in the recommendations. The wording of recommendations varied across guidelines. Recommendations were detailed and explained in the section of rationale and explanation of recommendations. In some guidelines, recommendations were accompanied with other material to assist their reporting.ConclusionsVariability and inconsistency were found on the reporting and presentation of recommendations in gout guidelines. Several points for reporting recommendation can be summarised. First, we suggested summarising and highlighting the core recommendations in a guideline. Second, guideline developers should try to structure and write recommendations reasonably. Third, it was necessary to detail and explain the recommendations and their rationale. Finally, describing and providing other potential useful contents was also a helpful way for clear reporting.

Melt post‐polycondensation (MPP) process is one of manufactures industrially that can efficiently increase the molecular weight of polycarbonate (PC). Herein, the MPP experiments of several PC materials using quaternary ammonium hydroxides and alkali metal compounds as the catalyst in the film state are studied. The reaction products are characterized by Ubbelohde viscometer, DSC, 1H‐NMR, ultraviolet spectrophotometry, advanced polymer chromatography and rotational rheometer. It is found that MPP can effectively improve the intrinsic viscosity of PC. After a certain reaction time at a specific temperature, the number average molecular weight (Mn) of PC is raised from 19,000 to 54,600 g/mol. Furthermore, the 1H‐NMR results reveal that Fries rearrangement products are produced during the MPP process. Based on the functional group model, a reaction kinetic model, combining the effects of the main melt polycondensation reaction and the Fries rearrangement reaction, is established for the first time. The reaction rate constants at different temperatures and the reaction activation energies of the two PC materials are obtained. This work provides a new reaction kinetics model to guide the MPP process of PC, which contains Fries rearrangement reaction.

The melt fluidity of polycarbonate (PC) significantly influences the processing, while the melt viscosity depends on the molecular structure. Specifically, the melt viscosity increases sharply with the increase of polymerization degree.However, the influence mechanism of alkali metal catalysts on the fluidity by affecting the molecular structure remains unclear. Herein, high and low concentrations of NaOH catalysts were used to synthesize PC with different polycondensation degrees. The effect of NaOH catalyst content on the molecular structure and thus melt fluidity of PC were systematically characterized and discussed employing NMR spectroscopy, absolute and relative molecular weight, intrinsic viscosity, melt flow index, and thermal analysis. The results show that a random branched structure of the PC molecular chain caused by excess NaOH improves the melt flowability. However, the residual NaOH promotes the degradation of carbonate bonds during thermal processing, resulting in poor PC stability. Based on the above discussion, empirical fitting equations are proposed to describe the relationship between molecular structure and flow properties, which provides a new way to judge PC performance.

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