Objective To explore the correlation and lag effect between meteorological factors and the incidence of scarlet fever in Xicheng District, Beijing, and to provide a theoretical basis for the surveillance, early warning，and scientific prevention and control of scarlet fever. Methods Based on the daily scarlet fever incidence data and concurrent meteorological data in Xicheng District, Beijing from 2010 to 2019, the distributed lag non-linear model (DLNM) was used to analyze the impact of meteorological factors on the incidence of scarlet fever. Results The risk of scarlet fever was the highest when the daily average temperature was 34.2℃ with a lag of 0 days (RR=1.175, 95% CI:1.006-1.372). The risk was the second highest when the daily average temperature was 2.2℃ with a lag of 12 days (RR=1.123, 95% CI:1.044 -1.209). The cumulative relative risk of scarlet fever was statistically significant when the daily average temperature ranged from 27.2℃ to 34.2℃, with the highest cumulative relative risk at 34.2℃ (RR=1.906, 95%CI:1.215-2.989). When the daily average relative humidity was 19.5% with a lag of 6 days, the risk of scarlet fever incidence was the highest (RR=1.022, 95% CI: 1.005-1.040). The cumulative relative risk was statistically significant when the daily average relative humidity ranged from 24.7% to 40.2%, with the highest cumulative relative risk at 27.3% (RR=1.170, 95% CI: 1.020-1.343). The risk of scarlet fever was the highest when the daily average vapor pressure was 1.2 hPa with a lag of 5 days (RR=1.029, 95%CI:1.008-1.050). The cumulative relative risk of scarlet fever was statistically significant when the daily average vapor pressure was 1.2-7.4 hPa, and the highest cumulative risk was when the daily average vapor pressure was 1.2 hPa (RR=1.362, 95% CI:1.022-1.815). Conclusion There is a nonlinear relationship between meteorological factors and the incidence of scarlet fever in Xicheng District, Beijing, with a certain lag effect. Daily average temperature (27.2-34.2℃), daily average relative humidity (28.6~36.3%) and daily average vapor pressure (1.2-7.4 hPa) increase the risk of scarlet fever. These factors can be used as indicators for the prevention, control, surveillance, and early warning of scarlet fever.

Objective To construct a two-dimensional (2D) composite membrane and a three-dimensional (3D) biomimetic scaffold by silk fibroin (SF), type I collagen (Col-I) and hydroxyapatite (HA) blends in vitro, so as to study its physicochemical properties, as well as biocompatibility and explore the feasibility of its application in tissue engineering scaffold materials. Methods 2D composite membranes and 3D scaffolds were prepared by blending SF/Col-I/HA at the bottom of cell culture chamber and low temperature 3D printing combined with vacuum freeze drying. The biocompatibility was evaluated by mechanical property testing, scanning electron microscope and Micro-CT to examine the physicochemical properties of the material, and cell proliferation was detected to evaluate its biocompatibility. Results Stable 2D composite membrane and 3D porous structural scaffolds were obtained by blending and low temperature 3D printing. The mechanical properties were consistent. The pore size, water absorption, porosity and elastic modulus were all in accordance with the requirements of constructing tissue engineering bone. The scaffold was a grid-like white cube with good internal pore connectivity; HA was evenly distributed in the composite membrane, and the cells were attached to the composite membrane in a flat shape; the cells were distributed around pore walls of the scaffold. The shape of the shuttle was fusiform, and the growth and proliferation were good. Conclusions The composite membrane and 3D scaffold prepared by SF/Col-I/HA blending system had better pore connectivity and pore structure, which was beneficial to cell and tissue growth and nutrient transport. Its physicochemical properties and biocompatibility could meet the requirements of bone tissue engineering biomaterials.

Objective To investigate the role and mechanism of nico-tinamide adenine dinucleotide phosphate oxidase 4 (NAPHD oxidase 4,Nox4)-mediated reactive oxygen species (ROS) generation on high-dose dexamethasone (DEX) induced apoptosis in osteoblasts.Methods According to culture conditions,3rd passage of murine osteoblastic MC3T3-E 1 cells were divided into control group,Dexamethasone group,Dexamethasone+NAC (N-acetyl-L-cysteine) group,NAC group,Dexamethasone+DPI (Diphenyleneiodonium) group and DPI group.24 hours after culture,the morphology of osteoblasts was observed by inverted phase contrast microscope.Cell viability was determined by MTT assay.The generation of ROS in osteoblasts was measured using a fluorescent probe DCFH-DA.The apoptosis of each group was observed through Hoechst staining.The mRNA level and protein expression of Nox4 were detected by real-time quantitative PCR and Western Blot.In addition,after silence of Nox4 with small interfering RNA (siRNA),the ROS generation was further detected by a fluorescent probe DCFH-DA.Results After treatment with 1000 nmol DEX for 24 hours,compared to control group,the results of inverted phase contrast microscope and MTT showed that osteoblasts in DEX group exhibited more obvious signs of shrinkage and deformation with decreased cell viability.After intervene with NAC and DPI,morphology of osteoblasts was good with increased viability of osteoblasts.Compared to control group (5.86％± 0.28％),the production of ROS in DEX group (45.14％±1.49％) was significantly increased (P=0.000).The apoptotic rates in DEX group (29.60％± 1.52％) was significantly increased compared with control group (4.12％±0.67％) (P=0.000).Compared to DEX group,the production of ROS generation in DEX+NAC group (28.06％±1.61％) and DEX+DPI group (23.70％±1.28％) was significantly decreased (P=0.000).It presented that NAC or DPI significantly decreased the formation of ROS.Compared to DEX group,the apoptotic rate in DEX+NAC group (8.94％± 1.47％) and DEX+DPI group (12.96％±2.03％) was significantly decreased (P=0.000).It presented that NAC or DPI significantly decreased osteoblast apoptosis.In addition,the Nox4 mRNA level in DEX group was 2.67-fold compared with control group (t=-10.301,P=0.009).The difference had statistically significance.The protein expression of Nox4 in DEX group was 2.37-fold compared with control group (t=-15.542,P=0.004).The difference has statistically significance.After silence of Nox4 by siRNA,the generation of ROS in DEX+Nox4 siRNA group (14.53％± 1.00％) was decreased by 16.92％ compared with DEX group 31.45％±0.72％ (P=0.000).The difference had statistically significance.Conclusion Nox4-mediated ROS generation plays an important role in osteoblasts apoptosis induced by high-dose dexamethasone.It provided us the new target in the management of Nox4 to provide possible therapy for steroid-induced avascular necrosis of the femoral head (SANFH).

Objective To study the role of IL-18 in the pathogenesis and treatment of ulcerative colitis (UC). Method An enzyme-linked immunosorbent assay (ELISA) was utilized to detect the serum IL-18 level of 58 UC patients. Results The serum IL-18 level in acute period of UC patients was significantly higher than that in control ones(P < 0.05 ). There was no significant difference between remisson period of UC and control ones (P> 0.05). The serum IL-18 level was closely related with the degree of UC (P < 0.05),the mean concentration of serum IL-18 was significantly higher in patients with severe ulcerative colitis [ (392.78 ± 50.17)pg/ml]than in patients with mild colitis ulcerative [ (138.92 ± 23.41 )pg/ml]and in control ones. Serum IL-18 in active ulcerative colitis were positively related to clinical disease severity and activity or laboratory parameters,including CAI,serum CRP,erythrocyte sedimentation rates,or total leukocyte counts (r = 0.775,0.705,0.662,0.625,P < 0.01 ). The level of IL-18 was declined after treatment with corticoids(P< 0.05). Conclusions IL-18 might play an important role in the pathogenesis of UC. The measurement of IL-18 is helpful to estimate the disease activity of UC and it may be considered as laboratory and activity criteria for UC.