Stroke was demonstrated to correlate with seasonal variation. However, the relevant studies were incongruous. To better understand the rules of seasonal impact on ischemic stroke (IS) patients, we performed this meta-analysis. We systematically searched relevant observational studies in Pubmed, Web of science and Embase from January 1, 1980, to November 1, 2017, in English. Patients included in this study were adults who suffered from IS. Stata version 12.0 software was used to pool useful data and calculate incidence rate ratios (IRRs) and their 95% confidence intervals (CIs). We also performed heterogeneity and sensitivity analyses and evaluated publication bias. Thirty-three observational studies involving 234,196 participants were incorporated into the meta-analysis. Summer and December were regarded as reference, respectively. The IRRs were calculated showing: IRRWinter 1.05 (95% CI 1.04–1.07), IRRAutumn 1.03 (95% CI 1.02–1.04), IRRSpring 1.02 (95% CI 1.01–1.03). No obvious difference existed among 12 months. Stratified analyses on Köppen classification were also conducted. Between-study heterogeneity was discovered; however, predefined stratified analyses and meta-regression could not reduce this heterogeneity. Our meta-analysis has revealed very little seasonal variation in the overall study. Both cold and hot months may be high risky for IS after stratified by Köppen Climate Classification. Thus, a rationale to environmental setting of risky patient management could be provided. More studies with specific assessments are warranted for further comprehensive investigation.
A novel SBM-C-PBR was constructed for microalgae cultivation.Membrane fouling was greatly mitigated by membrane carbonation.NH4+ and P removal rates were around 80% in SBM-C-PBR.Biomass was completely retained by membrane. In this study, a novel sequence batch membrane carbonation photobioreactor was developed for microalgae cultivation. Herein, membrane module was endowed functions as microalgae retention and CO2 carbonation. The results in the batch experiments expressed that the relatively optimal pore size of membranes was 30 nm, photosynthetically active radiation was 36 W/m2 and the CO2 concentration was 10% (v/v). In long-term cultivation, the microalgal concentration separately accumulated up to 1179.0 mg/L and 1296.4 mg/L in two periods. The concentrations of chlorophyll a, chlorophyll b and carotenoids were increased about 23.2, 14.9 and 6.3 mg/L respectively in period I; meanwhile, the accumulation was about 25.0, 14.5, 6.6 mg/L respectively in the period II. Furthermore, the pH was kept about 5.5–7.5 due to intermittent carbonation mode, which was suitable for the growth of microalgae. Transmembrane pressure (TMP) was only increased by 0.19 and 0.16 bar in the end of periods I and II, respectively. The pure flux recovered to 75%–80% of the original value by only hydraulic cleaning. Scanning electron microscope images also illustrated that carbonation through membrane module could mitigate fouling levels greatly. 相似文献
Pilot-scale combustion is required to treat arsenic-enriched biomass in China.CaO addition to arsenic-enriched biomass reduces arsenic emission.CaO captures arsenic via chemical adsorption to form Ca3(AsO4)2. Large quantities of contaminated biomass due to phytoremediation were disposed through combustion in low-income rural regions of China. This process provided a solution to reduce waste volume and disposal cost. Pilot-scale combustion trials were conducted for in site disposal at phytoremediation sites. The reaction mechanism of arsenic capture during pilot-scale combustion should be determined to control the arsenic emission in flue gas. This study investigated three Pteris vittata L. biomass with a disposal capacity of 600 kg/d and different arsenic concentrations from three sites in China. The arsenic concentration in flue gas was greater than that of the national standard in the trial with no emission control, and the arsenic concentration in biomass was 486 mg/kg. CaO addition notably reduced arsenic emission in flue gas, and absorption was efficient when CaO was mixed with biomass at 10% of the total weight. For the trial with 10% CaO addition, arsenic recovery from ash reached 76%, which is an ~8-fold increase compared with the control. Synchrotron radiation analysis confirmed that calcium arsenate is the dominant reaction product. 相似文献
Estimated anthropogenic Hg emission was 11.9 tons in Pearl River Delta for 2014. Quantifying contributions of emission sources helps to provide control strategies. More attentions should be paid to Hg deposition around the large point sources. Power plant, industrial source and waste incinerator were priorities for control. A coordinated regional Hg emission control was important for controlling pollution. We used CMAQ-Hg to simulate mercury pollution and identify main sources in the Pearl River Delta (PRD) with updated local emission inventory and latest regional and global emissions. The total anthropogenic mercury emissions in the PRD for 2014 were 11,939.6 kg. Power plants and industrial boilers were dominant sectors, responsible for 29.4 and 22.7%. We first compared model predictions and observations and the results showed a good performance. Then five scenarios with power plants (PP), municipal solid waste incineration (MSWI), industrial point sources (IP), natural sources (NAT), and boundary conditions (BCs) zeroed out separately were simulated and compared with the base case. BCs was responsible for over 30% of annual average mercury concentration and total deposition while NAT contributed around 15%. Among the anthropogenic sources, IP (22.9%) was dominant with a contribution over 20.0% and PP (18.9%) and MSWI (11.2%) ranked second and third. Results also showed that power plants were the most important emission sources in the central PRD, where the ultra-low emission for thermal power units need to be strengthened. In the northern and western PRD, cement and metal productions were priorities for mercury control. The fast growth of municipal solid waste incineration were also a key factor in the core areas. In addition, a coordinated regional mercury emission control was important for effectively controlling pollution. In the future, mercury emissions will decrease as control measures are strengthened, more attention should be paid to mercury deposition around the large point sources as high levels of pollution are observed. 相似文献
The adverse impacts of lead and cadmium exposure on health outcomes have been reported in the past. Few studies have been conducted on the relationship between lead and cadmium exposures and disability. We evaluated whether lead and cadmium exposures were associated with functional dependence including the total number of disabilities, activities of daily living (ADL), instrumental activities of daily living (IADL), leisure and social activities (LSA), lower extremity mobility (LEM), and general physical activities (GPA) in an elderly population. A total of 5513 eligible subjects were enrolled in the study from the National Health and Nutrition Examination Survey 2001–2006. Serum lead and cadmium exposure assessments were performed using atomic absorption spectrometry. Functional dependence was assessed by 19 structured questions. The relationships between lead and cadmium exposures and functional dependence were investigated using by multivariable linear regression models. Q2, Q3, and Q4 of lead exposure were significantly associated with the total number of disabilities, with β coefficients of ??0.62 (95% CI ??0.99, ??0.24), ??0.64 (95% CI ??1.02, ??0.26), and ??0.81 (95% CI ??1.19, ??0.42), respectively. This relationship remained significant in males. Furthermore, we analyzed the relationships between lead and cadmium exposure quartiles and various functional dependence metrics, and we determined that lead content was significantly associated with decreased ADL, LEM, and GPA (p?<?0.05) and cadmium content was inversely associated with ADL (p?<?0.05). Our study demonstrated a strong relationship between exposure to lead and cadmium and functional dependence in an elderly population.