Search

Confined groundwater is an indispensable resource for the urban security of Shanghai, China, where multi-layer aquifer structures and human activities create a complex groundwater environment. An understanding of the hydrochemical characteristics and evolutionary mechanisms of groundwater is necessary for its protection and effective utilization and will be explored in this study. A total of 87 groundwater samples were collected from five confined aquifers. Hydrochemistry analysis methods such as Durov diagram, Gibbs model and Saturation index were used to determine the origin and hydrochemical evolution of the confined groundwater. The results show that the samples have two different origins, marine–continental and continental, which have different hydrochemical characteristics. Cl− content of 7.5 meq L−1 was used as a demarcation index for the two origins. The groundwater with a marine–continental-origin is dominated by ancient seawater from which Na+ and Cl− are derived, whereas Ca2+, Mg2+, and HCO3− are derived mainly from carbonate dissolution. Groundwater with a continental-origin is dominated by the effects of water–rock interaction, where major ions are derived mainly from silicate weathering and carbonate dissolution. In both types of groundwater, SO42− is mainly derived from insoluble sulfides that are present in low quantities, whereas SO42− in the few samples with high insoluble sulfide content is derived from human activities. Cation exchange is another controlling factor regarding the hydrochemical composition of groundwater, and water from the two origins have different reaction modes as follows: reverse cation exchange is dominant in marine–continental groundwater, whereas positive cation exchange is more common in continental groundwater. Over the past century, saline water has been flowing into the groundwater funnel region due to human activities, which has resulted in changes in the hydrochemical composition. The recent influx of fresh groundwater and artificial recharge has caused groundwater salinization and mineral re-dissolution.

To compare the Stretta procedure with proton pump inhibitors for the treatment of nonerosive reflux disease (NERD). From July 2018 to April 2019, patients diagnosed with NERD and referred for treatment were enrolled. They were treated with either Stretta procedure or proton pump inhibitor (PPI) medication and followed-up for 6 months. The symptom control, quality of life, lower esophageal sphincter (LES) pressure, 24-hour pH parameters, PPI usage and satisfaction rate were evaluated. The complications were assessed. The outcomes of the 2 groups were analyzed and compared. Twenty-eight patients in the Stretta group and 21 patients in the PPI group completed the 6-month follow-up. No severe adverse events occurred in both groups. Both interventions were effective in improvement of symptom and quality of life. The symptom score improvement was significantly superior in the Stretta group compared to the PPI group (6.3 ± 3.4 vs 8.5 ± 4.1, P = .03). LES pressure increased significantly in the Stretta group compared to the PPI group (14.2 ± 4.4 mm Hg vs 10.0 ± 4.0 mm Hg, P

In order to make sure the security and sustainable development of the urban rail transit, the PS-InSAR technology is introduced into the deformation monitoring of urban rail transit. Taking Shanghai as an example, it is analyzed that the characteristics of surface deformation along the rail transit. Firstly, 26 TerraSAR-X images are used to carry out the high-resolution PS-InSAR subsidence fine measurements in Shanghai for the overall land subsiding characteristics of rail transit. Then, the detail subsidence pattern and the driving force is discussed by classified the rail transit with different construction periods and building modes. Finally, the accuracy of the results is verified by leveling in the same period. The results show that rapid urbanization construction has become a main reason for the subsidence of Shanghai rail transit. Rail transit with different construction periods and building modes show various deformation characteristics. Earlier sections are more stable than later sections and elevated sections have smaller subsidence rate than underground sections. The verification results show fairly consistent agreement. The results further illustrate that it is feasible to use the high-resolution PS-InSAR technology into the deformation monitoring, management, maintenance and early warning of urban public transportation projects. It can also provide decision support for planning and construction of urban public transportation.