Search

One quarter of the world's population uses karst groundwater. Due to the complex hydrological conditions in karst areas, they are vulnerable to pollution. The study of the hydrochemical characteristics and environmental quality evaluations of karst groundwater is of great significance for the rational development and utilization of karst groundwater. The study area is located in the Mengzi area of Yunnan Province, which is a typical karst area. The groundwater in the study area was analyzed and evaluated by a statistical analysis, hydrogeochemical analysis, ion ratio and Nemerow's index method (PN). The results show that the hydrochemical types are mainly the Ca–HCO3 and Ca–Mg–HCO3 types. The main hydrochemical compositions of groundwater were controlled by carbonate dissolution. The results of the water quality evaluation show that the main pollutants in the study area are Mn, COD and NO3−. Compared with groundwater, the concentration and exceeding rate of pollutants in surface water are much higher than those in groundwater. There is the possibility of groundwater pollution by surface water infiltration. The results reveal the characteristics of groundwater pollution in typical karst areas and provide a theoretical basis for the rational development and utilization of groundwater. [ABSTRACT FROM AUTHOR]

Although molecular imaging probes have the potential to non-invasively diagnose a tumor, imaging probes that can detect a tumor and simultaneously identify tumor malignancy remain elusive. Here, we demonstrate a potassium ion (K+) sensitive dual-mode nanoprobe (KDMN) for non-invasive tumor imaging and malignancy identification, which operates via a cascaded 'AND' logic gate controlled by inputs of magnetic resonance imaging (MRI) and fluorescence imaging (FI) signals. We encapsulate commercial K+ indicators into the hollow cavities of magnetic mesoporous silica nanoparticles, which are subsequently coated with a K+-selective membrane that exclusively permits the passage of K+ while excluding other cations. The KDMN can readily accumulate in tumors and enhance the MRI contrast after systemic administration. Spatial information of the tumor lesion is thus accessible via MRI and forms the first layer of the 'AND' gate. Meanwhile, the KDMN selectively captures K+ and prevents interference from other cations, triggering a K+-activated FI signal as the second layer of the 'AND' gate in the case of a malignant tumor with a high extracellular K+ level. This dual-mode imaging approach effectively eliminates false positive or negative diagnostic results and allows for non-invasive imaging of tumor malignancy with high sensitivity and accuracy. [ABSTRACT FROM AUTHOR]

Improving the state-owned assets supervision system (SOASS) can effectively get over the defects of systems and mechanisms and further prornate the reform of mixed ownership of state-owned enterprises (SOEs); and the deepening of the reform can advance the change of the SOASS to the supervision on capital. By analyzing the relationship between the SOASS and the reform of mixed ownership of state-owned enterprises, we have found that collaborative promotion of the change of the SOASS to the supervision on capital and promotion of the reform of mixed ownership can do good to ameliorating the corporate management mechanism, improving the market-oriented management mechanism of enterprises and completing the medium- and long-term incentive mechanisms, etc. to enhance business operation efficiency. Due to such prevailing problems as relative dispersion and vagueness of the policies relating to deepening the reform of SOEs, inconsistent progress of the reform of state-owned assets (SOAs) and SOEs, and corporate reform focusing on apprence, improving the SOASS and deepening collaborative development of the reform of mixed ownership of SOEs are hindered by some constraints. To construct and improve the SOASS and the reform of mixed ownership collaboratively, we should make efforts to promote the reform in the following five aspects, namely, placing importance to policy coordination. boosting synchronism of the reform of SOAs and SOEs at different levels and in different areas to coordinate the nationwide reform of SOAs and SOEs, facilitating reform of the mechanism of enterprises of mixed ownership through mixed capital, and promoting the SOASS and stimulating classified monitoring and reform of mixed ownership based on classified reform of SOEs. [ABSTRACT FROM AUTHOR]