Objective　To observe the clinical results of total lamellar cornea with circular lamellar sclera transplantation to treat serious chemical burn of eye and study its immunological mechanisms.Methods　The patients(55 cases, 55 eyes) with corneal tansplantation were retrospectively analyzed. GroupⅠ(42 cases) was the patients with serious chemical burn of eye transplantation of total lamellar cornea with circular lamellar sclera, group Ⅱ(13 cases) was the patients transplantation of total cornea corresponding period of the groupⅠ. The time of tear-film break-up their rate of rejection and the time of occurrence of corneal neovascularization were compared.Results　The time of occurrence of corneal neovascularization and rejection of group Ⅰ were later than groupⅡ.Conclusion　Total lamellar cornea with circular lamellar sclera transplantation is an important method for treating serious chemical burn of eye, its immunological mechanisms is complex. It's important to increase the result of operation keeping high standard in quality of tear-film and using high effective immunosuppressive drug after operation.

Objective To explore the relationship of four kinds of lifestyle factors,namely,prenatal passive smoking,hair dyeing or perming,exposure to noise,living in a house renovated in the past one year,with congenital heart disease.Methods A hospital-based case-control study was conducted.Totally 270 mothers in the case group and 1633 mothers in the control group were interviewed through a face-to-face questionnaire survey.A generalized linear model was employed to investigate the association between congenital heart disease and prenatal lifestyle factors.Results Both in Model 1 and Model 2,prenatal hair dyeing or perming had no association with congenital heart disease.On the other hand,prenatal passive smoking,exposure to noise and living in a house renovated in the past one year all increased the risk of congenital heart disease.After adjustment for all confounders,the OR values were 1.771 (95％ CI:1.079-2.909),2.079 (95％ CI:1.310-3.298),and 2.494 (95％ CI:1.511-4.116),respectively.Conclusion Prenatal passive smoking,exposure to noise and living in a house renovated in the past one year are the risk factors for congenital heart disease.It is very important to avoid such factors during pre-pregnancy and pregnancy.

ObjectiveObjective To systematically evaluate the efficacy and safety of antiviral therapy in patients with chronic hepatitis B (CHB) in the immune-tolerant phase. MethodsPubMed, Embase, Cochrane Library, CNKI, and Wanfang Data were searched for clinical trials of antiviral therapy for CHB patients in the immune-tolerant phase published up to September 2020. Related data were extracted after quality assessment for systematic review. HBV DNA clearance rate was the primary outcome. ResultsA total of 9 studies involving 821 patients were included. Eight studies reported HBV DNA clearance rate in the treatment group, among which 6 studies had an HBV DNA clearance rate of ＞60%, which was significantly higher than that in the untreated patients (0%-29.1%), and the combination therapy group had a better clearance rate than the monotherapy group. However, virologic recurrence was more common in the long term. Eight studies reported HBeAg seroconversion, and only 2 studies of the treatment of children with interferon-α (IFN-α) reported a seroconversion rate of ＞20% in the treatment group, which was higher than that in the untreated group. HBsAg clearance was observed in 2 studies of IFN-α treatment, while HBsAg seroconversion was not observed. One study reported the risk of liver cirrhosis and hepatocellular carcinoma (HCC) and showed that antiviral therapy could reduce the risk of liver cirrhosis and HCC in patients. The incidence rate of adverse events ranged from 4.1%-13.0% in the treatment with nucleos(t)ide analogues and reached 100% in the treatment with IFN-α, and serious adverse events were rare. ConclusionThe majority of CHB patients in the immune-tolerant phase show satisfactory virologic response after antiviral therapy, but they tend to experience recurrence after drug withdrawal and have a low seroconversion rate. Antiviral therapy has good safety. Current evidence suggests that such patients can be dynamically observed if there is no clear evidence for disease progression.

Objective:Data being missed is an unavoidable problem in cohort studies. This paper compares the imputation effect of eight common missing data imputation methods involved in cutting longitudinal data through simulation study to provide a valuable reference for the treatment of missing data in longitudinal studies.Methods:The simulation study is based on R language software and generates missing longitudinal data by the Monte Carlo method. By comparing the average absolute deviation, average relative deviation, and TypeⅠerror from the regression analysis of different imputation methods, the imputation effect of varying imputation methods on missing longitudinal data and the influence on subsequent multivariate analysis are evaluated.Results:The mean imputation, k nearest neighbor (KNN), regression imputation, and random forest all have a similar imputation effect, which is also steady. However, the hot deck is inferior to the above imputation methods. K-means clustering and expectation maximization (EM) algorithm are among the worst and unstable. Mean imputation, EM algorithm, random forest, KNN, and regression imputation can control TypeⅠerror. Still, multiple imputations, hot deck, and K-means clustering cannot effectively manage the TypeⅠerror.Conclusions:For missing data in longitudinal studies, mean imputation, KNN, regression imputation, and random forest can be used as better imputation methods under the mechanism of missing at random. When the missing ratio is not too large, multiple imputations and hot deck can also perform well, but K-means clustering and EM algorithm are not recommended.

Objective:To analyze the epidemiological characteristics and transmission chain of an epidemic of COVID-19 in Haidian district, Beijing.Methods:Descriptive epidemiological method was used to analyze the epidemiological characteristics of the epidemic, and field investigation and big data technology were used to analyze the transmission chain of the epidemic.Results:From April 27 to May 13, 2022, an epidemic of COVID-19 occurred in Haidian district. The strains isolated from the cases were identified by whole genome sequencing as Omicron variant (BA.2.2 evolutionary branch). A total of 38 infection cases were detected, including 34 confirmed cases and 4 asymptomatic cases. Most cases were mild ones (88.2%), no severe, critical or death cases occurred. The early clinical symptoms were mainly sore throat (50.0%) and cough (29.4%). The epidemic lasted for 17 days, resulting in 7 generations of the cases and involving 3 community transmissions, 2 working place transmissions and 8 family transmissions; the main infection routes were co-residence (47.6%) and co-space exposure (31.6%). The intergenerational interval M( Q1, Q3)was 3 (1, 6) days. The overall secondary attack rate was 1.5% (37/2 482), and the family secondary attack rate was 36.7% (18/49). Conclusions:The cases in this COVID-19 epidemic caused by Omicron variant had mild clinical symptoms, but the case clustering in families and communities was obvious, the transmission was rapid, and the risk for co-space exposure was high. It is necessary to use information technology to identify close contacts in the local population for the rapid and effective blocking of the epidemic spread.

Objective To explore the effect of exposure to noise of 3.0T magnetic resonance imaging(MRI)on children's cochlear function.Methods We prospectively recruited 72 children who underwent cranial MRI examination at our hospital from May to November 2018;3M earplugs and sponge mats were used for hearing protection during MRI scanning.Noise level(dBA)of each MRI sequence was detected with a nonmagnetic microphone and a sound level meter.Distortion product otoacoustic emissions(DPOAE)test at 2-7 kHz was performed 24 hours before and 30 minutes after the MRI examination.Paired t-test or Wilcoxon signed-rank test was used to analyze differences in DPOAE amplitude before and after the MRI examination.Results The average noise level of MRI measured in the study was(107.7±3.92)dBA.Compared with that before the MRI examination,the DPOAE amplitude(dB)changed little after the MRI examination;the range of amplitude differences in each age group was as follows:left ear(-0.24-1.10)and right ear(-0.24-0.74)in the 0-1 year-old group;left ear(-0.07-0.59)and right ear(-0.57-0.75)in the 2-5 year-old group;left ear(-0.36-0.44)and right ear(-0.30-0.57)in the 6-12 year-old group.No statistically significant difference was found(correction P＞0.05).Conclusion No potential impact of 3.0T MRI noise on children's cochlear function was observed under routine hearing protection.

【Objective】 To compare the performance of five commonly used variable selection methods in high-dimensional biomedical data variable screening so as to explore the effects of sample size and association among candidate variables on screening results and provide evidence for the development of variable selection strategy in high-dimensional biomedical data analysis. 【Methods】 Variable selection algorithms were implemented based on R-programming language. Monte Carlo method was used to simulate high-dimensional biomedical data under different conditions to evaluate and compare the performance of different variable selection methods. Variable selection performance was evaluated based on the true positive rate and true negative rate in screening. 【Results】 For specified high-dimensional data, the variable selection performance was improved for all the methods when sample size was increased, and the association between candidate variables did affect variable screening results. Simulation results indicated that the elastic network algorithm yielded the best screening performance, LASSO algorithm took the second place, and ridge algorithm did not work at all. 【Conclusion】 Elastic network algorithm is an ideal variable screening method for high-dimensional data variable screening.

【Objective】 To estimate the prevalence, associated factors and patterns of multimorbidity of non-communicable diseases among adults in Shaanxi Province so as to provide evidence for the prevention and control of non-communicable diseases. 【Methods】 We used the data of adults aged 18 years and older collected in the baseline survey of Shaanxi Project in the Regional Ethnic Cohort Study in Northwest China. Multinomial logistic regression was used to explore the associated factors for multimorbidity. Exploratory factor analysis was used to extract patterns of multimorbidity. 【Results】 The prevalence of multimorbidity was 10.7% among the 44 442 participants. Age increase, being males, urban residence, and being overweight or obesity were positively associated with multimorbidity. Compared with women, men had a higher risk of multimorbidity. The OR and 95% CI was 1.25 (1.12-1.39). The risk of multimorbidity increased with age among adults. Compared with participants aged 18.0-34.9 years, the ORs and 95% CIs of those aged 35.0-44.9, 45.0-54.9, 55.0-64.9, and ≥65.0 years were 4.73 (3.47-6.46), 15.61 (11.60-21.00), 41.39 (30.76-55.70) and 90.04 (66.58-121.77), respectively. The primary multimorbidity patterns among adults in Shaanxi were cardiovascular-metabolic multimorbidity (5.4%), viscero-articular multimorbidity (1.0%), and respiratory multimorbidity (0.3%). 【Conclusion】 More than one in ten adults in Shaanxi Province had multimorbidity, and the predominant pattern of multimorbidity was cardiovascular-metabolic multimorbidity. The prevention and control of non-communicable diseases should be reinforced in middle-aged and older people, males, people living in the urban, and overweight or obese people. More attention should be paid to the prevention and control of cardiovascular-metabolic diseases.