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This study examined the associations between dissolved organic matter (DOM) characteristics and potential nitrification occurrence in the presence of chloramine along a drinking water distribution system. High-performance size exclusion chromatography (HPSEC) coupled with a multiple wavelength detector (200–280 nm) was employed to characterise DOM by molecular weight distribution, bacterial activity was analysed using flow cytometry, and a package of simple analytical tools, such as dissolved organic carbon, absorbance at 254 nm, nitrate, nitrite, ammonia and total disinfectant residual were also applied and their applicability to indicate water quality changes in distribution systems were also evaluated. Results showed that multi-wavelength HPSEC analysis was useful to provide information about DOM character while changes in molecule weight profiles at wavelengths less than 230 nm were also able to be related to other water quality parameters. Correct selection of the UV wavelengths can be an important factor for providing appropriate indicators associated with different DOM compositions. DOM molecular weight in the range of 0.2–0.5 kDa measured at 210 nm correlated positively with oxidised nitrogen concentration ( r = 0.99), and the concentrations of active bacterial cells in the distribution system ( r = 0.85). Our study also showed that the changes of DOM character and bacterial cells were significant in those sampling points that had decreases in total disinfectant residual. HPSEC-UV measured at 210 nm and flow cytometry can detect the changes of low molecular weight of DOM and bacterial levels, respectively, when nitrification occurred within the chloraminated distribution system. [ABSTRACT FROM AUTHOR]

Understanding the complexity of dissolved organic matter (DOM) in stormwater has drawn a lot of interest, since DOM from stormwater causes not only environmental impacts, but also worsens downstream aquatic quality associated with water supply and treatability. This study introduced and employed high-performance size exclusion chromatography (HPSEC) coupled with an ultraviolet–visible (UV–vis) diode array detector to assess changes in stormwater-associated DOM characteristics. Stormwater DOM was also analysed in relation to storm event characteristics, water quality and spectroscopic analysis. Statistical tools were used to determine the correlations within DOM and water quality measurements. Results showed that dissolved organic carbon (DOC) and UV absorbance at 254 nm (UV 254 ) as conventional DOM parameters were found to be correlated well to the changes in stormwater quality during each of the three storm events studied. Both detector wavelengths (210 and 254 nm) and their ratio (A 210 /A 254 ) were found to provide additional information on the physiochemical properties of stormwater-associated DOM. This study indicated that A 210 /A 254 is an important parameter which could be used to estimate the DOM proportions of functional groups and conjugated carbon species. This study provided also an understanding of stormwater quality constituents through assessing variability and sensitivity for various parameters, and the additional information of rainfall characteristics on runoff quality data for a better understanding of parameter correlations and influences. [ABSTRACT FROM AUTHOR]

• Shear reinforcement corrosion tests on reinforced concrete cold joint specimens were carried out. • Push-off test on reinforced concrete specimens after shear reinforcement corrosion was firstly performed. • The degradation mechanism of cold joint shear behavior after shear reinforcement corrosion was revealed. • Relationships between cold joint shear strength and shear reinforcement corrosion degree were proposed. This paper experimentally investigated the interface shear transfer between concretes cast at different times (that is, cold joints) after shear reinforcement corrosion. Twelve cold joint push-off specimens were cast and the impressed current accelerated corrosion test was used to obtain different values of shear reinforcement corrosion degree. Push-off tests were then conducted to study the shear transfer behavior of cold joint after shear reinforcement corrosion. The push-off test results indicate that cold joints with different values of shear reinforcement corrosion degree exhibit distinct failure modes. As the corrosion degree increases, the interface failure mode gradually changes from shearing off of the shear reinforcements to spalling of the concrete cover. The shear capacity and failure load of interface reduce and the interface deformation (relative slip and crack width) at the shear capacity increases with the increase of corrosion degree. The stiffness of shear load-interface deformation response is reduced and a more ductile shear transfer behavior is observed after shear reinforcement corrosion. The shear mechanism analysis results reveal that the reduction of interface shear capacity is mainly due to the decrease of interface adhesion or cohesion caused by the shear reinforcement corrosion, and the decrease of interface failure load attributes to the change of the interface failure mode. Based on the statistical analysis of the test data in this paper, the equations for predicting the shear strength and failure strength of cold joint after shear reinforcement corrosion are proposed. [ABSTRACT FROM AUTHOR]

• Theoretical framework of water-energy-carbon nexus on land use was established. • The carbon emission/absorption and its intensity vary among different land use types. • The carbon emissions from different land use types will reach peak at different time. • It has great potential of carbon emission reduction under the scenario of water-energy-land saving. The rapid urban expansion of China has led to a large amount of water and energy consumption, and caused drastic growth of carbon emissions. Discovering the water–energy–carbon nexus of different land use types helps explain the interactions between resources capacity and environmental effects of land use activities, as well as provides reasonable options for land use management based on water–energy conservation and carbon emission reduction. In this paper, carbon emission/absorption of different land use types was estimated and the water–energy–carbon nexus of different land use types in Zhengzhou was analyzed. Through the SD model, the future carbon emissions of different scenarios were predicted under water, energy, and land constraints. It showed that total carbon emission increased and carbon absorption reduced along with the land use change during the rapid urbanization process of Zhengzhou city. The water and energy consumption and carbon emissions of different land use types were determined by the different intensities and their spatial patterns of human activities. Therefore, carbon emission and its intensity varied with land use types and water–energy–carbon nexus was closely related to land use types. The carbon emission prediction showed that the carbon emission reduction potential was the highest and the peak carbon emission (40.18 × 106 t) occurred in 2025 under a comprehensive scenario, which was designed with water–energy saving and optimization of land use structure. This study could provide references for policy–makers to formulate differentiated strategies for different land use activities, and contribute to realize water–energy saving and efficient utilization of land and the emission reduction of Zhengzhou city. [ABSTRACT FROM AUTHOR]

Objectives: To explore the role of core self-evaluation in mediating between depressive symptoms and suicidal ideation in Chinese adolescents.Methods: We used the cluster sampling method to analyze 11,563 students from five primary and secondary schools in China for depressive symptoms, core self-evaluation, and suicidal ideation using the following scoring scales: Core Self-Evaluation Scale (CSES), Center for Epidemiologic Survey Depression Scale (CES-D), the Second Edition of the Beck Depression Inventory (BDI- II), Screen for Child Anxiety Related Emotional Disorders (SCARED), and Adolescent Self-Rating Life Events Checklist (ASLEC).Results: The incidence of depression was 29.7%; anxiety, 34.2%; and suicidal ideation, 28.0%. Core self-evaluation was a protective factor for suicidal ideation [OR 0.947, 95% CI 0.937-0.959, p<0.001]. Conversely, depression as measured by the CSES score was a risk factor for suicidal ideation (OR 1.084, 95% CI 1.073-1.096, p<0.001), as were anxiety as measured by the SCARED score (OR 1.011, 95% CI 1.006-1.016, p<0.001) and adolescent life events according to ASLEC score groups (OR 1.524, 95% CI 1.434-1.621, p<0.001). Core self-evaluation mediated the relationship between depression and suicidal ideation with an effect size of 13.9%.Conclusions: Better core self-evaluation is a protective factor against suicidal ideation and mediates the relationship between depression and suicidal ideation. We may be able to reduce the risk of suicidal ideation and therefore suicide among adolescents by improving their core self-evaluation. [ABSTRACT FROM AUTHOR]

Atherosclerosis, the leading cause of cardiovascular diseases in the world, is a chronic inflammatory disorder characterized by the dysfunction of arteries. Oleanolic acid (OA) is a bioactive nature product which exists in various plants and herbs. Previous studies have demonstrated that OA was involved in numerous of biological processes, including atherosclerosis. However, the exact mechanisms of the anti-atherosclerosis effects of OA remain unknown. Here, in our study, we analyzed the effects and possible underlying mechanisms of OA in atherosclerosis depending a cell model and an animal model of atherosclerosis. Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL, 100 μg/mL) for 24 h to establish an atherosclerotic cell model. New Zealand white (NZW) rabbits were fed with high-fat (HF) diets for three months to establish an atherosclerotic animal model. Then, cell viability and expression of cytokines (ANG, NO, eNOS, IL-1β, TNF-α, and IL-6) were measured with CCK-8 assay and ELISA kits, cell apoptosis and cell cycle distribution were analyzed by flow cytometry in the atherosclerotic cell model. Results showed that ox-LDL induced effects of anti-proliferation, cytokines alterations, and cell apoptosis were abolished by the application of OA or Ang (1–7). Further study indicated that OA increased the expression of ANG by upregulating the FXR expression in the ox-LDL induced HUVECs arthrosclerosis model. And the in vivo experiment in the HF diet induced animal model suggested that OA may inhibit the development of atherosclerosis. The atherosclerosis of aortas was assessed by Hematoxylin Eosin (HE), Oil Red O and Picrosirius Red staining; the expression levels of total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C) were determined by the fully automatic biochemical analyzer, in the atherosclerotic animal model. All the results showed that OA treatment improved the cell viability in the cell model, inhibited the atherosclerosis development in the animal model. OA play as an anti-atherosclerosis agent in both the cell model and animal model by upregulating the production of Angiotensin (Ang)-(1–7) through FXR. [ABSTRACT FROM AUTHOR]

Abstract: We have synthesized multi-wall carbon nanotubes by catalytic chemical vapour deposition (CCVD) method using an AB5 hydrogen storage alloy with diameter ranging from 38 to 150μm as a catalyst. The H2 uptake capacity of the carbon nanotubes prepared using an AB5 alloy as a catalyst is about 4wt.% through to the pressure of 8MPa at room temperature. Differential thermal analysis–thermogravimetric analysis (DTA–TGA) technique has been applied to investigate the effect of the diameters of the AB5 alloy catalyst of micrometer magnitude and the technique conditions in the CCVD process on the thermal properties of carbon nanotubes. As the catalyst diameter increases from 38 to 150μm, the average diameter of the prepared carbon nanotubes increases and the diameter distribution also enlarges. Electron microscope, Raman spectrum and thermal analysis all indicated that the catalyst sizes affect the diameter and the thermal properties of the carbon nanotubes. When the catalyst diameter increases, the initial weight loss temperature and the differential thermal peak temperature of the carbon nanotubes increases, which shows that the lager the diameter of the carbon nanotubes is, the higher the oxidation temperature, and the better the anti-oxidizablity. However, if the diameter of the catalyst is larger than 100μm, the anti-oxidizablity does not rise anymore but tend to be invariableness. In the CCVD preparation process, the anti-oxidizability of the carbon nanotubes increases, when raising the ratio of the hydrogen gas in the reaction gas in our experimental range (4:1, 3:1, and 2:1, respectively). [Copyright &y& Elsevier]