Objective:To examine the adiponectin level in gingival crevicular fluid(GCF)in patients of chronic periodontitis with dia-betes mellitus type 2.Methods:20 patients of diabetes mellitus type 2 with chronic periodontitis(DM&CP),20 of periodontitis(CP) and 20 health subjects(H)were included.The periodontal indexes (SBI,PLI,PD and AL)were measured,GCF samples were quan-tified by periotron 8000,the adiponectin content in GCF was tested by adiponectin ELISA kit.The relationship between the adiponectin level in GCF and the periodontal indexes of the DM&CP patients was analyzed statistically.Results:The adiponectin level in GCF in group DM&CP was significantly lower than that in the other 2 groups(P <0.05).The adiponectin levels in GCF in group CP and H were not statistically different.The adiponectin level in GCF was negatively correlated with PD and AL(P <0.05),but had no correlation with SBI and PLI(P >0.05).Conclusion:Decrease of adiponectin in GCF may play a role in the development of DM&CP.

Objective:To observe the epidemiological characteristics and transmission chain of COVID-19 in Harbin, and to provide epidemiological evidence for improving the COVID-19 preventive measures and optimizing prevention and control strategies.Methods:The epidemic situation of COVID-19 in Harbin in January 2021 was analyzed by using the Infectious Disease Report Information Management System and the Public Health Emergency Management Information System of the China Disease Prevention and Control Information System, the epidemic situation information publicly released by the Heilongjiang Provincial Health Commission, and the epidemiological report of Heilongjiang Province Certer for Disease Control and Prevention and Harbin Center for Disease Control and Prevention. The main transmission chains were sorted out through combination of epidemiological field investigation, serological testing, gene sequencing, big data and other means.Results:From January 12 to February 4, 2021, 295 cases of COVID-19 infection (including confirmed cases and asymptomatic infections) were reported in Harbin, which affected 6 districts of Harbin and were concentrated in 41 of the 274 townships in the city. The sex ratio of male to female was 1.00∶1.12 (139∶156); the age ranged from 1 to 86 years old, and the median age was 45 years old. The proportion of confirmed cases and asymptomatic infection was 1.00 ∶ 1.02 (146 ∶ 149), and there was a significant difference in the distribution of different ages between them ( P = 0.042). The cases were mainly found through the health screening of the centralized isolation personnel (178 cases, 60.3%). Other detection methods included active screening (87 cases, 29.5%), screening of the home isolation personnel (26 cases, 8.8%), and medical treatment in medical institutions (4 cases, 1.4%). The main transmission chain of the outbreak was the case associated with a food processing enterprise, with a total of 259 cases, accounting for 87.8% of the total cases. The gene sequencing results showed that the case sequence was homologous with that of Wangkui County, Suihua City, Heilongjiang Province. Conclusions:A food processing enterprise is involved in the main transmission chain, which indicates that the epidemic prevention and control measures needs to be further optimized. Specifically, the supervision and management of food processing enterprises, cold chain storage companies and other enterprises should be strengthened. High attention should be paid to the hidden dangers of COVID-19 in large and medium sized enterprises with hermetic space in Harbin.

Hand, foot, and mouth disease (HFMD) is a common childhood infectious disease caused by various enteroviruses. China has the most significant number of reported cases and deaths of HFMD over the globe. Understanding the epidemic laws of HFMD can provide a scientific basis for designing prevention and control measures. The dynamic transmission models focus on the transmission mechanism of infectious diseases. They can simulate the actual situation to study the epidemic rules of diseases by adding, deleting, and subdividing compartments. More researchers have paid attention to dynamic models because of their high flexibility. To carry out the dynamic model of the HFMD research more effectively, a comprehensive understanding of related research progress in this field is deeply needed. In this paper, based on various researchers' different research purposes of dynamic models, the research progress was classified and summarized, providing meaningful guidance for model construction methods and future research directions and references for dynamic modeling of other models of infectious diseases. It was found that most studies used the SIR dynamic model or its extended model (such as the SEIR model), and few studies contained a complex factor compartment. Some important epidemiological parameters (such as R0) were obtained by studying the HFMD cases in a specific region, simulating different intervention scenarios to evaluate the effect of measures, or revealing the future trend by model prediction. However, there is no dynamic model simultaneously considering age structure, population moving, seasonality and periodicity, and vaccination.