BACKGROUND:The traditional fixation method for femoral neck fractures is three hollow screws inverted triangle fixation,and the optimal fixation method for femoral neck fractures that have not achieved anatomical reduction is inconclusive. OBJECTIVE:To compare the biomechanical properties of cannulated screws internal fixation for sub-capitated femoral neck fracture with different reduction qualities based on finite element analysis. METHODS:The three-dimensional digital model was reconstructed using CT data of the proximal femur from a healthy male volunteer.The femur was modeled to sub-capitated femoral neck fractures.Fracture models were divided into anatomical reduction group,coxa vara group,and coxa valgus group.All fracture model groups were transferred using the standard group,screw depression group,and screw elevation group.A vertical downward stress of 1 400 N was applied to the femoral head at the top of the acetabulum.The displacement and stress distribution of the femur and internal fixator under different fixation methods were observed,and the maximum stress and displacement of the femur and fixator were compared. RESULTS AND CONCLUSION:(1)For anatomical reduction femoral neck fracture,the peak stress of fixation in the standard group,screw depression group and screw elevation group was 41.35,31.27 and 43.32 MPa,respectively.The maximum peak stress of the femur was found on the screw elevation group(28.58 MPa),and the standard group had the maximum peak displacement.(2)During hip varus,the stresses in the three subgroups were relatively dispersed and even.The peak stress of the femur in the standard group was the smallest,but the peak displacement was the largest.The stability of fixation might be poor.The peak displacement of the femur in the screw depression group was the smallest.(3)In the hip valgus,obvious screw stress concentration appeared in the screw depression group,and the peak displacement was the largest among the three subgroups,and an in-out-in phenomenon appeared.The peak stress of the screws in the screw elevation group was the largest among the three subgroups,but the peak displacement was the smallest.(4)It is concluded that for sub-capitated femoral neck fractures that are completely anatomically reduced,it is recommended to use standard inverted triangular nails for fixation.When the hip varus and hip valgus occur within the allowable range of the reduction standard,it is recommended to use the inverted triangle screw to fix it by rotating the corresponding angle in the same direction as the hip varus or valgus.

OBJECTIVES: This study aims to predict the risk of deep caries exposure in radiographic images based on the convolutional neural network model, compare the prediction results of the network model with those of senior dentists, evaluate the performance of the model for teaching and training stomatological students and young dentists, and assist dentists to clarify treatment plans and conduct good doctor-patient communication before surgery. METHODS: A total of 206 cases of pulpitis caused by deep caries were selected from the Department of Stomatological Hospital of Tianjin Medical University from 2019 to 2022. According to the inclusion and exclusion criteria, 104 cases of pulpitis were exposed during the decaying preparation period and 102 cases of pulpitis were not exposed. The 206 radiographic images collected were randomly divided into three groups according to the proportion: 126 radiographic images in the training set, 40 radiographic images in the validation set, and 40 radiographic images in the test set. Three convolutional neural networks, visual geometry group network (VGG), residual network (ResNet), and dense convolutional network (DenseNet) were selected to analyze the rules of the radiographic images in the training set. The radiographic images of the validation set were used to adjust the super parameters of the network. Finally, 40 radiographic images of the test set were used to evaluate the performance of the three network models. A senior dentist specializing in dental pulp was selected to predict whether the deep caries of 40 radiographic images in the test set were exposed. The gold standard is whether the pulp is exposed after decaying the prepared hole during the clinical operation. The prediction effect of the three network models (VGG, ResNet, and DenseNet) and the senior dentist on the pulp exposure of 40 radiographic images in the test set were compared using receiver operating characteristic (ROC) curve, area under the ROC curve (AUC), accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F1 score to select the best network model. RESULTS: The best network model was DenseNet model, with AUC of 0.97. The AUC values of the ResNet model, VGG model, and the senior dentist were 0.89, 0.78, and 0.87, respectively. Accuracy was not statistically different between the senior dentist (0.850) and the DenseNet model (0.850)(P>0.05). Kappa consistency test showed moderate reliability (Kappa=0.6>0.4, P<0.05). CONCLUSIONS Among the three convolutional neural network models, the DenseNet model has the best predictive effect on whether deep caries are exposed in imaging. The predictive effect of this model is equivalent to the level of senior dentists specializing in dental pulp.
Humans ; Deep Learning ; Neural Networks, Computer ; Pulpitis/diagnostic imaging* ; Reproducibility of Results ; ROC Curve ; Random Allocation

Objective:To explore the teaching effect and novel ideas of online teaching applied in skill operation course.Methods:One hundred and fifty-one students studying in Sichuan University taking the First Aid in the Life: Basic Knowledge and Skills as an elective course in the autumn semester of 2019 and spring semester of 2020 were included as the research subjects in this study. Among them, 77 students in the spring semester of 2020 were selected as the experimental group and 74 students in the autumn semester of 2019 were selected as the control group. The students in the experimental group studied the first aid course by online platform, and the others in the control group studied through traditional teaching mode. The teaching effect of the two groups was compared and the teaching satisfaction of the two groups weas analyzed. SPSS 23.0 was used for Chi-square test and t-test. Results:There was no significant difference between the control group and the experimental group in the assessment scores of cardiopulmonary resuscitation, hemostatic bandaging, and fracture fixation [(8.65±0.81 vs 8.69±0.90, P=0.750); (8.10±0.50 vs 8.12±0.61, P=0.880); (8.21±0.89 vs 8.16±0.78, P=0.710)]. Among the students participating in the questionnaire survey in the experimental group, 59 (95.16%) students thought that this course was helpful in dealing with first aid in daily life, and 38 (61.29%) students did not want to change the traditional teaching method to online teaching. Conclusion:The application of online teaching in first-aid skill operation course is feasible and can achieve the similar teaching effect, which provides a novel idea for exploring the online teaching of first aid skills.

Objective To analyze the clinical efficacy and safety off emoral head replacement(FHR)assisting by the traction table in direct anterior approach(DAA)for the treatment of femur neck fractures in gerontal patients.Methods A retrospective analysis was conducted on 79 elderly patients who under went FHR for femoral neck fractures from March 2019 to July 2020.A total of 42 patients underwent FHR through DAA by using traction table were assigned to the observation group and 37 patients receiving FHR through the PLA to the control group.The perioperative data,follow-up results and complications were compared between the two groups.Results The observation group was significantly superior to the control group in intraoperative blood loss(P<0.05),where as the former was inferior to the latter in preoperative preparation time(P<0.05).There was no significant difference in anesthesia time and operation time between the two groups(P>0.05).The observation group resumed first postoperative standing time,partial-weight bearing walking time and full-weight bearing walk-ing time significantly earlier than control group(P<0.05).Harris score at 1 month after the operation in the observation group were significantly higher than that of the control group(P<0.05),whereas which became not statistical significant between the two groups in 6 months and 1 year(P>0.05).No significant difference was found between the two groups for the incidence of complications(P>0.05).Conclusion DAA-FHR assisting by the traction table for the treatment of femur neck fractures in the elderly was effective and safe,but the preoperative preparation time was longer.

Objective: To study the influence of environmental factors on the two-species biofilm formed by the combinations of Streptococcus oligofermentans (So) with Streptococcus mutans (Sm) and Streptococcus sanguinis (Ss) with Sm so as to evaluate the role of So in maintaining the microecological balance of the oral cavity. Methods: Single-and two-species biofilms were grown on saliva-coated surfaces (glass tube and 96-well plate). Colony-counting method and safranin staining method were used to measure the biofilms formed under various oxygen conditions (aerobic and anaerobic), sucrose conditions (0%, 1% and 5% sucrose concentrations) and pH conditions (5.5, 6.0, 6.5, 7.0, 7.5 and 8.0). Results: Comparing the numbers of Sm in two co-cultures under various conditions, Sm counts in So+Sm group [(7.70±2.46)×10⁸ CFU/ml] were significantly lower than those in Ss+Sm group [(9.00±1.13)×10⁸ CFU/ml] in aerobic environment (P<0.05). Sm counts in So+Sm group [(2.80±0.52)×10⁸ CFU/ml] were also significantly lower than those in the Ss+Sm group [(4.00±1.25)×10⁸ CFU/ml] in anaerobic environment (P<0.05). The Sm counts in So+Sm group [(8.90±0.82)×10⁸ CFU/ml] were significantly higher than those in Ss+Sm group [(7.50±1.73)×10⁸ CFU/ml] in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group [(5.70±2.94)×10⁸ CFU/ml] were significantly lower than those in Ss+Sm group [(10.30±3.21) ×10⁸ CFU/ml] in 1% sucrose environment (P<0.05). The Sm counts in So+Sm group [(6.10±1.71)×10⁸ CFU/ml] were also significantly lower than those in Ss+Sm group [(7.40±1.20)×10⁸ CFU/ml] in 5% sucrose environment (P<0.05). The Sm counts in So+Sm group [(3.50±1.50)×10⁸ CFU/ml] were significantly lower than those in Ss+Sm group [(10.70±2.80)×10⁸ CFU/ml] in pH7.0 environment (P<0.05). Comparing the formation of biofilm after 24 h cultivation, the Sm counts in So+Sm group were significantly lower than those in Ss+Sm group both in aerobic and anaerobic environments (P<0.05). The Sm counts in So+Sm group were significantly higher than those in Ss+Sm group in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group were significantly lower than those in Ss+Sm group in 1% and 5% sucrose and pH 7.0 environments (P<0.05). Both So and Ss had no inhibitory effect on Sm in pH5.5 and pH8.0 environments. Conclusions In the in vitro two-species co-culture systems, So showed stronger inhibitory effects than Ss on Sm and its inhibitory ability might influenced by various environmental factors.

Objective To study the influence of environmental factors on the two?species biofilm formed by the combinations of Streptococcus oligofermentans (So) with Streptococcus mutans (Sm) and Streptococcus sanguinis (Ss) with Sm so as to evaluate the role of So in maintaining the microecological balance of the oral cavity. Methods Single?and two?species biofilms were grown on saliva?coated surfaces (glass tube and 96?well plate). Colony?counting method and safranin staining method were used to measure the biofilms formed under various oxygen conditions (aerobic and anaerobic), sucrose conditions (0%, 1% and 5% sucrose concentrations) and pH conditions (5.5, 6.0, 6.5, 7.0, 7.5 and 8.0). Results Comparing the numbers of Sm in two co?cultures under various conditions, Sm counts in So+Sm group [(7.70 ± 2.46)× 108 CFU/ml] were significantly lower than those in Ss+Sm group [(9.00 ± 1.13)×108 CFU/ml] in aerobic environment (P<0.05). Sm counts in So+Sm group [(2.80±0.52)×108 CFU/ml] were also significantly lower than those in the Ss+Sm group [(4.00±1.25)×108 CFU/ml] in anaerobic environment (P<0.05). The Sm counts in So+Sm group [(8.90±0.82)×108 CFU/ml] were significantly higher than those in Ss+Sm group [(7.50± 1.73)×108 CFU/ml] in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group [(5.70 ± 2.94)× 108 CFU/ml] were significantly lower than those in Ss+Sm group [(10.30±3.21)×108 CFU/ml] in 1% sucrose environment (P<0.05). The Sm counts in So+Sm group [(6.10±1.71)×108 CFU/ml] were also significantly lower than those in Ss+Sm group [(7.40±1.20)×108 CFU/ml] in 5% sucrose environment (P<0.05). The Sm counts in So+Sm group [(3.50 ± 1.50)×108 CFU/ml] were significantly lower than those in Ss+Sm group [(10.70±2.80)×108 CFU/ml] in pH7.0 environment (P<0.05). Comparing the formation of biofilm after 24 h cultivation, the Sm counts in So+Sm group were significantly lower than those in Ss+Sm group both in aerobic and anaerobic environments (P<0.05). The Sm counts in So+Sm group were significantly higher than those in Ss+Sm group in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group were significantly lower than those in Ss+Sm group in 1% and 5% sucrose and pH 7.0 environments (P<0.05). Both So and Ss had no inhibitory effect on Sm in pH5.5 and pH8.0 environments. Conclusions In the in vitro two?species co?culture systems, So showed stronger inhibitory effects than Ss on Sm and its inhibitory ability might influenced by various environmental factors.

Objective: To investigate the status of abnormal menstruation in female nurses in a comprehensive hospital in Beijing, China and related influencing factors. Methods: In July 2016, a cross-sectional survey was performed, and a self-administered questionnaire was used to investigate the status of menstruation and occupation in female nurses in a comprehensive hospital in Beijing. The chi-square test and a multivariate logistic regression analysis were used for statistical analysis. Results: A total of 892 female nurses were investigated, and among them, 485 experienced abnormal menstruation within the past three months, resulting in an abnormal menstruation rate of 54.37%. The female nurses who were exposed to harmful factors during work, negative life events, or high workload had a significantly higher abnormal menstruation rate than those who were not exposed to such factors (χ²=5.199, 16.186, and 10.227, P<0.05 or P<0.01) . Negative life events (odds ratio [OR]=1.813, 95% confidence interval[CI]: 1.317-2.496) and high workload (OR=1.461, 95%CI: 1.112-1.918) were risk factors for abnormal menstruation. Conclusion Nurses have an abnormal menstruation rate as high as 54.37%, and high workload and negative life events were risk factors for abnormal menstruation in nurses.

Objective: To investigate the prevalence of reproductive system diseases among female workers in a city and related occupational influencing factors. Methods: From June to September, 2016, a cross-sectional survey was used to select 9 944 female workers from six districts of Beijing and then a face-to-face questionnaire survey was performed. Univariate analysis using chi-square test and multivariate logistic regression analysis were used to investigate the risk factors for reproductive system diseases. Results: The age of 9944 female workers ranged from 18 to 65 years (mean 35.53±9.52 years) , and among them, 7 351 (73.92%) were married. The overall prevalence rate of reproductive system diseases among these 9944 female workers during the past three months was 28.29%, and the prevalence rates of hyperplasia of mammary glands, vaginitis, and hysteromyoma were 15.54%, 11.25%, and 6.77%, respectively. After adjustment for age, marital status, education level, and annual family income, the multivariate logistic regression analysis showed that frequent overtime work (odds ratio[OR]=1.119, 95% confidence interval[CI]: 1.070-1.343) , frequent night shifts (OR=1.198, 95%CI: 1.054-1.361) , standing for a long time (OR=1.197, 95%CI: 1.063-1.347) , sitting for a long time (OR=1.327, 95%CI: 1.191-1.479) , heavy workload (OR=1.429, 95%CI: 1.262-1.615) , exposure to lead (OR=1.696, 95%CI: 1.307-2.201) , exposure to mercury (OR=1.452, 95%CI: 1.086-1.940) , and exposure to ionizing radiation (OR=1.679, 95%CI: 1.424-1.980) were associated with reproductive system diseases. Conclusion The prevalence of reproductive system diseases among female workers in Beijing is not optimistic. Reproductive system diseases are associated with frequent overtime work, frequent night shifts, standing for a long time, sitting for a long time, heavy workload, and exposure to lead, mercury, and ionizing radiation.

Objective: To investigate the application of Symptom Checklist-90 (SCL-90) in Chinese nurses. Methods: We performed a literature search for articles in Chinese on the mental health of nurses investigated using the SCL-90 that were published from January 2007 to December 2016. A total of 129 articles were included, involving 178 groups of valid samples as well as 36316 subjects in 27 provinces or cities in China. The metafor package of R 3.2.1 software and Excel were used for meta-analysis and data statistics. Results: Heterogeneity was identified for the nine factors included in the literature data (Q test: P<0.05; I² test >40%) , so a random effects model was used. For all factors except interpersonal relationship factor, the 95% confidence intervals of the pooled effect sizes did not include 0. For all factors except interpersonal relationship factor (Egger test: P<0.05) , no significant asymmetry or incompleteness appeared in the funnel plots. The fail-safe number of each factor was much larger than 5k+10. The merger scores and mean values of nine factors were higher than the national norm. Conclusion The SCL-90 is widely used in the study of mental status of Chinese nurses, but the SCL-90 norm for nurses is lacking.

Objective: To evaluate the mental health of female doctors and nurses. Methods: Investigat the psychologic status of female doctors and nurses using symptom checklist 90. And statistical software was applied to analyze results of symptom checklist 90. Results: There were differences in the score of SCL-90 between doctor and nurse groups, the difference was statistically significant (P<0.05) . Negative life events (OR=2.940) , relative suffer from mental illness (OR=3.683) , shift work (OR=1.611) and heavy workload (OR=2.265) were found to risk factors for the positive of SCL-90. Conclusion There were differences in the score of SCL-90 between doctor and nurse groups. Negative life events, relative suffer from mental illness, shift workand heavy workload are risk factors for SCL-90 positive of female doctors and nurses.