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An experimental investigation of circular concrete-filled steel tubular (CFST) columns subjected to very low-elevation lateral impacts was performed. Six circular CFST members were prepared for lateral impact tests according to the typical CFST columns in high-speed railway stations in China, and the impact location was at the height of the 2/9 column. The tests had three variables: the thickness of the steel tube, the impact velocity, and the axial load. The failure modes were determined in the tests, along with the time histories of the impact force and the deflection at the impact location. A finite-element analysis was performed to examine the effects of the axial load and scaling on the maximum deflection. The results show that with the increase of axial compression ratio, the impact resistance of the member first increases and then weakens. According to the travelling plastic hinge theory, a three-stage rigid plastic mechanical model was employed to describe the impact process, in which the impact location was at the non-mid-span, and a deflection calculation method for CFST applicable to any impact position was developed. A comparison with the test results indicated that deflections can be calculated with reasonable accuracy using the proposed method. [ABSTRACT FROM AUTHOR]

Urban reservoirs serve many purposes including recreation and drinking water, and larger bodies of water can alter the surrounding air temperatures, making urban areas cooler in summer and warmer in winter. However, reservoirs may also be sinks for contaminants. One such group of contaminants, the polybrominated diphenyl ethers (PBDEs), are persistent organic pollutants known to accumulate in sediments and suspended particulate matter (SPM). Few studies have been conducted on PBDEs in water, SPM, and sediment from reservoirs of Shenzhen which is a mega city in South China. To this end, 12 PBDEs were measured in water, SPM, and sediment samples during the dry season (DS) and wet season (WS), to explain the spatiotemporal distribution, congener profiles, sources, and risks of pollutants in four reservoirs (A–D) and their tributaries in the study region. The concentration of ∑12PBDEs during the DS was found to be significantly higher than that during the WS. Source apportionment suggested that commercial penta-, octa-, and deca-BDEs are the major components of PBDEs, resulting mainly from atmospheric deposition, wastewater discharge, and external water-diversion projects. Further, attention should be paid to electronic equipment manufacturing factories in the study area. Risk assessment indicated risk of PBDEs (especially BDE-209) in sediment and SPM to be of concern. This study provides important data support for the control of PBDEs in natural drinking water sources. [ABSTRACT FROM AUTHOR]

Aims: This study was conducted over 10 years using an open top chamber experiment in the Sanjiang Plain to explore the impact of environmental parameters and bacterial community composition and structure under long-term conditions of elevated CO2 concentrations (eCO2, 550 μmol·mol−1). Methods: Illumina sequencing of 16S rRNA was used to determine soil bacterial communities over the long-term in the Sanjiang Plain. Vegetation characteristics and soil properties were also investigated. Results: Dominant bacterial group was Proteobacteria, accounting for 23.52–39.03%, while there were remarkable changes in the bacterial community composition. eCO2 increased the relative abundance of Subgroup_6 and decreased those of AD3 and Candidatus_Udaeobacter. These variations might be related to gene functions. A redundancy analysis indicated that there was a strong relationship between dominant bacterial phyla and environmental factors (photosynthetic rate, aboveground biomass and stomatal conductance). Structural equation model (SEM) showed that eCO2 and year both affected the soil bacterial community. In contrast, the short-term had greater impacts on the bacterial community under eCO2 compared with the long-term via indirect effects on vegetation and soil characteristics. Conclusions: eCO2 affect soil bacterial community through indirect effects on soil nutrient content and vegetation characteristics in the short-term whereas showed adaptability to eCO2 in the long term. [ABSTRACT FROM AUTHOR]

Although the production of polybrominated diphenyl ethers (PBDEs) has been phased out over the past decade worldwide, they are still potentially hazardous to the environment due to their persistence and toxicity. This study investigated the levels of 55 PBDEs in water and sediments from the Danjiangkou Reservoir, China. The levels of PBDEs were in the range of not detected (ND)–286.67 ng/L in water and ND–236.04 ng/g in sediments. BDE209 was the predominant PBDE congener and constituted 15–50% and 44–68% of the total PBDEs in water and sediments, respectively. Commercial pentaBDE products (70-5DE, DE-71) were the dominant source of tetraBDE, pentaBDE, and hexaBDE, while commercial octaBDE (79-8DE) and decaBDE (102E and 82-0DE) products were the main sources of nonaBDE and decaBDE in water. PBDEs in sediments mainly stemmed from commercial decaBDE products and combustion sources. BDE-209 posed high ecological risks to aquatic organisms and dominated the total ecological risks of PBDEs. No cancer risks and non-cancer risks were observed for PBDEs. A ranking method based on four criteria, i.e., detection frequency, concentration, ecological risk, and health risks, was proposed, and 17 PBDEs were identified as high priority PBDEs for future monitoring and management in the Danjiangkou Reservoir. [ABSTRACT FROM AUTHOR]

In this study, we assessed the prevalence of overt and occult hepatitis B virus (HBV) infection among leukemia patients. Among 256 leukemia patients and 377 fracture patients (control group), we found that the hepatitis B surface-antigen-positive rate was greater in leukemia patients than in the controls (odds ratio, 2.08; p = 0.01). Moreover, the prevalence of occult HBV infection was higher in leukemia patients than in the controls (10.5 % vs. 2.9 %; odds ratio, 3.92; p < 0.001). The HBV genotype distribution differed significantly between the leukemia and chronic hepatitis B or control groups ( p < 0.001 and 0.01, respectively); specifically, genotype C was primarily observed in occult HBV infection patients with leukemia. The stop codon mutation rate or amino acid substitutions in the major hydrophilic region did not differ between the groups. Thus, the prevalence of occult hepatitis B is higher in leukemia patients, and the HBV genotype distribution differs between patients with leukemia and chronic hepatitis B virus infection. [ABSTRACT FROM AUTHOR]