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Light steel structure with added stories is a economic and effective method of strengthening design for existing buildings, and it is promoted and applied widely. But it still has some problems about computing of seismic action effect. The computing is not simply in accordance with the base shear method. The value of dynamic magnification factor which was counted as ß needs further research. In this paper, the value of is 2 on the basis of theoretical analysis and calculation example. The safety factor of the value is higher, and the design with the ß is more economic and reasonable.

This paper summarized the current research situation and development direction of the storey adding structure all over the country. On the basis of the situation, combined characteristics of light steel storey adding structure, the article analyzed adding structure's damping distribution regularity. Based on the complex damping theory, through the mode-superposition method, there was established the correction formula of the earthquake response spectrum of light steel storey adding structure considered the effects of damping. All above, the article provides the basis for the study on the dynamic properties of light steel storey adding structure.

According to the study of added stories structure form for existing buildings, the basic form and characteristics of existing four added stories structure were analyzed and summarized in this paper. According to the research, light steel structure with added storey as a economic and effective method of strengthening design for existing building, it is promoted and applied widely. But there are some problems in the identification of design standard, the reasonable choice of structure scheme, the calculation of Seismic effect and constitution design to be solved.

Background Asthma is the most common disease in children, and its pathogenesis is highly complicated. Methods CD4+ cells and CD4+ IL-17+ cells were analysed by flow cytometry, and the ratio of CD4+ cells to the peripheral blood mononuclear cells (PBMCs) and CD4+ IL-17+ cells to PMBCs were calculated from the control group, acute group, and moderate group. The levels of protein expression of IL-6, IL-17, and IL-21 were detected by ELISA in the plasma and culture supernatants of PBMCs of the three groups. The correlations between IL-7 and IL-6, IL-7 and IL-21 were analysed in culture supernatants of PBMCs of the three groups. Results The mean ratio of CD4+ IL-17+ cells/peripheral blood mononuclear cells (PBMCs) was 4.32% in the acute group, which was higher than in the control group and moderate group. The levels of IL-6 and IL-17 were elevated, and the levels of IL-21 were decreased in the acute group. The levels of IL-17 and IL-6 were positively correlated (r = 0.182, p = 0.03), and the levels of IL-17 and IL-21 were negatively correlated (r = -0.834, p = 0.02). Conclusions The results suggest that the levels of IL-17 and IL-6 are related to the severity of asthma. Furthermore, IL-17 may play a role in the development of childhood asthma.