An integrated urbanization level (CL) index and an integrated natural disaster intensity (QC) index were developed on the basis of Disaster System Theory and China Natural Disaster Database for integrated urban disaster risk assessment. Integrated quantitative assessments of the urban socio-economic system and the intensity of hazards in China were carried out by the Model-Tupu (map series) and inter-feedback process using digital map technology. On the basis of this assessment, China can be regionalized into three regions, namely, coastal urban disaster region, eastern urban disaster region and western urban disaster region, 15 sub-regions and 22 units. These results can provide a scientific basis for determining a city's disaster risk management and natural disaster relief regionalization in China.

Calcineurin (CN) is a heterodimer consisting of a catalytic subunit (CNA) and a regulatory subunit (CNB). The crystal structure shows that three residues or regions of CNA are mainly responsible for the interaction with CNB: the CNB binding helix (BBH), the N-terminus, and Glu53 that forms a salt bridge with Lys134 of CNB. In this report, we try to find the role that the salt bridge plays in the interaction between CNA and CNB. We found that mutation of Glu53 greatly reduced its responsiveness to CNB in the phosphatase assay and also that mutation of Lys134 of CNB affected its ability to activate the phosphatase activity of CNA. Structural analysis showed that disruption of the salt bridge affected the compact association of CNA and CNB. Thus, the salt bridge appears to help to stabilize CN and transfer the effects of CNB binding to CNA to activate its phosphatase activity.