Stably suspended SiO2-supported CdS photocatalyst for a promising organic pollutant degradation in the absence of mechanical stirring.

Even with solar-activatable photocatalyst, incommensurable energy input for stirring is still required to overcome the transport limitations in powder-photocatalysis. To counter this, a novel concept of auto-suspending photocatalyst based on SiO2/CdS was proposed to enable promising photo-activity even under stirring-free condition. Functionally-speaking, CdS would act as photoreaction-driver while SiO2 endows sufficient buoyance for suspension-stabilization during stirring-free photocatalysis. In photoreactions degrading methylene blue for theoretical demonstration, SiO2/CdS_0.3 promises only 4.57% activity reduction in non-stirred photoreaction, enabling 15.26% of methylene blue decolorization comparing to 15.99% of stirred-photoreaction under visible light irradiation. This could be ascribed to the slow settling tendency of SiO2/CdS_0.3, evading severe light-shielding under stacked condition. Also, its rightly-exposed SiO2 surface permits 'adsorb-and-degrade' mechanism, thereby overcoming the sluggish surface transport across thick boundary layer. Contrarily, photocatalyst with quintuple CdS content (SiO2/CdS_1.5) exhibits largest activity reduction (31.47%), reasoned by its quick-settling tendency. Overall, current study provides new perspectives to photocatalysis-community. The success elimination of mechanical stirring from photocatalysis promises significant energy-saving (19.1-136 kW/m3), thus consenting better practicality for solar energy-harvesting and environmental protection.

Proton pump inhibitors therapy and the risk of pneumonia: a systematic review and meta-analysis of randomized controlled trials and observational studies.

OBJECTIVE: We aimed to summarize the current evidence regarding the risk of pneumonia associated with proton pump inhibitors (PPI) treatment. METHODS: We searched PubMed, Embase, and CENTRAL from the 1970 through December 2017. We included both randomized controlled trials (RCTs) and observational studies. We used random-effect model to calculate the summary effect estimates and quantified the heterogeneity by I2 statistics. RESULTS: A total of 7,643,982 patients from 10 RCTs and 48 observational studies were included in this meta-analysis. The primary meta-analysis demonstrated PPIs use was significantly associated with increased risk of pneumonia, but the heterogeneity was high (odds ratio [OR], 1.43; 95% confidence interval [CI], 1.30-1.57; I2, 95.4%). The sensitivity analysis indicated PPIs were not statistically associated with increased risk of pneumonia among patients concomitantly taking nonsteroidal anti-inflammatory drugs (OR, 1.11; 95% CI, 0.94-1.31; I2, 5.8%). The funnel plot demonstrated significant publication bias, especially for observational studies. CONCLUSIONS: The presence of significant between-study heterogeneity and publication bias raised concerns regarding the validity of the primary meta-analytic result. Protopathic bias, or reverse causality, may cause overestimated association. Studies that adopted a design to account for protopathic bias did not show a significant association between PPI use and risk of pneumonia.