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Journal of Zhejiang University. Medical sciences ; (6): 68-73, 2021.
Article in English | WPRIM | ID: wpr-879950


:To predict the epidemiological trend of coronavirus disease 2019 (COVID-19) by mathematical modeling based on the population mobility and the epidemic prevention and control measures. : As of February 8,2020,the information of 151 confirmed cases in Yueqing,Zhejiang province were obtained,including patients' infection process,population mobility between Yueqing and Wuhan,etc. To simulate and predict the development trend of COVID-19 in Yueqing, the study established two-stage mathematical models,integrating the population mobility data with the date of symptom appearance of confirmed cases and the transmission dynamics of imported and local cases. : It was found that in the early stage of the pandemic,the number of daily imported cases from Wuhan (using the date of symptom appearance) was positively associated with the number of population travelling from Wuhan to Yueqing on the same day and 6 and 9 days before that. The study predicted that the final outbreak size in Yueqing would be 170 according to the number of imported cases estimated by consulting the population number travelling from Wuhan to Yueqing and the susceptible-exposed-infectious-recovered (SEIR) model; while the number would be 165 if using the reported daily number of imported cases. These estimates were close to the 170,the actual monitoring number of cases in Yueqing as of April 27,2020. : The two-stage modeling approach used in this study can accurately predict COVID-19 epidemiological trend.

Humans , COVID-19 , China/epidemiology , Disease Outbreaks , Models, Theoretical , Pandemics , SARS-CoV-2
Chinese Journal of Industrial Hygiene and Occupational Diseases ; (12): 243-245, 2002.
Article in Chinese | WPRIM | ID: wpr-340093


<p><b>OBJECTIVE</b>To explore whether the superposition of an electromagnetic noise can block gap-junctional intercellular communication(GJIC) suppression induced by 50 Hz 0.4 mT extremely low frequency magnetic field(ELF MF).</p><p><b>METHODS</b>Fibroblast cells of mice(NIH 3T3) were exposed to 0.4 mT ELF MF or(and) electromagnetic noise with the same intensity of MF for 24 h, and the GJIC was determined by using fluorescence recovery after photobleaching(FRAP) analysis, which was performed with a laser-scanning confocal microscope(Leica, Germany).</p><p><b>RESULTS</b>ELF MF exposure significantly inhibited GJIC with fluorescence recovery rate of 27.67% +/- 5.12% as compared with the control group(45.57% +/- 9.72%) (P < 0.01), while that of ELF MF plus noise group was (52.61% +/- 8.30%), which was significantly different from ELF MF group(P < 0.01), but not from control(P > 0.05).</p><p><b>CONCLUSION</b>Electromagnetic noise could block the GJIC suppression induced by 50 Hz 0.4 mT MF.</p>

Animals , Mice , Cell Communication , Radiation Effects , Electromagnetic Fields , Gap Junctions , Radiation Effects , NIH 3T3 Cells , Noise
Chinese Journal of Industrial Hygiene and Occupational Diseases ; (12): 246-248, 2002.
Article in Chinese | WPRIM | ID: wpr-340092


<p><b>OBJECTIVE</b>To investigate the possible interference effect of electromagnetic noise exposure on phosphorylation of stress-activated protein kinase(SAPK) induced by 50 Hz magnetic field(MF).</p><p><b>METHODS</b>Chinese hamster lung(CHL) cells were exposed to sham exposure(C), 0.4 mT 50 Hz sinusoidal MF, 0.4 mT electromagnetic noise and the combined noise MF with 50 Hz MF for 3 min and 15 min respectively. After exposure, the cells were lysed, and the proteins were extracted. The SAPK and phosphorylated SAPK (activated form of SAPK) were measured indirectly by Western blot with corresponding antibodies. The percentage of phosphorylated SAPK was calculated and analyzed.</p><p><b>RESULTS</b>Exposure of cells to 50 Hz MF for 3 min and 15 min enhanced the SAPK phosphorylation. The percentage of phosphorylated SAPK were 49.3% and 57.0% respectively, and were significantly different from those of control(P < 0.05, n = 4). However, single noise MF exposure with the same intensity did not enhance the SAPK phosphorylation, the percentage of phosphorylated SAPK were 37.7% and 31.8% (P > 0.05). When cells were exposed to the combined noise MF with 50 Hz MF for 3 min, the SAPK phosphorylation was significantly inhibited (24.4%, P < 0.05); for 15 min, the SAPK phosphorylation was also decreased (39.0%), but there was no significant difference from control and 50 Hz MF exposure(P > 0.05).</p><p><b>CONCLUSION</b>Noise MF with certain intensity could inhibit the biological effect induced by 50 Hz MF.</p>

Animals , Cricetinae , Cell Line , Cricetulus , Electromagnetic Fields , Mitogen-Activated Protein Kinases , Metabolism , Noise , Phosphorylation
Microbiology ; (12)1992.
Article in Chinese | WPRIM | ID: wpr-683702


Three methods for isolation of nitrite oxidizers-dilution method, silica-gel plate method and enrichment culture-capillary pipette method were compared. Among them the dilution method was most feasible and efficient.