Objective The biomechanical model for the musculoskeletal system of a human knee joint was established using a numerical simulation method.The kinematic and dynamic information captured during jumping motion simulated by the human dynamic model was used as driven data of the knee biomechanical model,followed by further analysis of the stress field distribution characteristics of the meniscus under different thermal-force coupling knee brace conditions.Methods Based on computed tomography and magnetic resonance imaging of the subject,a realistic human knee model,including bone,articular cartilage,meniscus,ligaments and peripheral soft tissues of the knee joint,was constructed.Furthermore,two gaits,namely taking-off and landing-on,of jumping motion with an increased risk of meniscus injuries were selected according to mechanical features in full-cycle jumping motion.Subsequently,the stress field characteristics of the knee meniscus under four different thermal-force coupling knee braces were analyzed,the changes of the peak stress of the meniscus and its stress concentration area were discussed,and the protective efficacy and mechanical basis of meniscal injuries and wearing knee braces were explored.Results The anterior part of the medial knee meniscus was a vulnerable area under concentrated stress.Under the knee brace thermal-force coupling condition,the stress concentration area of the medial meniscus was transferred from its narrow and weak anterior part to its wide and thick middle part,and the peak stress was also significantly reduced.The peak stress on the medial meniscus and that on the lateral meniscus were similar,indicating that the two parts of the meniscus bore the external load evenly,and the meniscus stress concentration area decreased.Conclusions Thermal-force coupling knee braces have good protective effects against knee meniscus injury.The numerical simulation provides theoretical support and technical guidance for the design of multifunctional thermal knee braces.

Objective:To investigate the effect of BOPPPS teaching model combined with virtual simulation technologyin the teaching of Prevention and treatment of Major Infectious Diseases,in order to explore innovative teaching model and provide evidence for improving students'comprehensive ability to deal with major infectious disease events.Methods:Undergraduates from three classes of preventive medicine major in a medical university were selected as the research objects.One class was given the new teaching model,and the other two classes were given the traditional teaching model.The total scores,the theoretical score and the skill score were compared between the two groups.Results:A total of 141 students participated in the survey,49 students in the new teaching model group,and 92 students in the traditional teaching model group.The results showed that compared with the traditional model group,the total score,the theoretical score,the skill score of the new model group was significantly higher(P＜0.01).However,there was no significant difference between male and female students in each group(P＞0.05).Conclusions:Compared with the traditional teaching model,the students in the new teaching model has a good teaching effect,which can improve the students'theoretical knowledge level,cultivate the students'emergency response ability,and improve the students'comprehensive ability of discovery,analysis and solution.Boys and girls have the same acceptance of the two teaching models,and gender does not affect the teaching effect.

Objective:To analyze the risk factors of acute kidney injury (AKI) in hip fracture patients with serious underlying diseases and establish a prediction nomogram.Methods:Clinical information of hip fracture patients admitted to the intensive care unit (ICU) of Beth Israel Deaconess Medical Center (BIDMC) was analyzed using the Medical Information Mart for Intensive Care (MIMIC)-IV. Patient comorbidities, disease scores, vital signs and laboratory tests, surgical modalities, invasive procedures, and drug use were recorded. According to the diagnostic criteria of AKI in the Kidney Disease Improving Global Outcome (KDIGO) guideline, the enrolled patients were randomly divided into training set and validation set. Based on logistic regression analysis, least absolute shrinkage and selection operator (LASSO) logistic regression algorithm was used to analyze the risk factors of AKI after admission, and the corresponding prediction model was calculated.Results:A total of 474 patients were enrolled, including 331 in the training set and 143 in the validation set. According to the diagnostic criteria of AKI of KDIGO guidelines, the patients were divided into AKI group (159 cases) and non-AKI group (172 cases). Univariate analysis showed that age ( t=2.61, P=0.009), coronary heart disease (χ 2=2.08, P=0.038), heart failure (χ 2=2.60, P=0.009), hemoglobin ( t=1.89, P=0.059), platelets ( t=1.81, P=0.070), urea nitrogen ( t=2.83, P=0.005), blood creatinine ( t=3.65, P<0.001), blood sodium ( t=2.55, P=0.011), blood glucose ( t=2.52, P=0.012), anion gap ( t=3.44, P=0.001), diastolic blood pressure ( t=2.72, P=0.007), mean arterial pressure ( t=2.16, P=0.031), SOFA score ( t=3.69, P<0.001), simplified acute physiological function score II (SAPSII) score ( t=2.95, P=0.003), as well as furosemide (χ 2=2.03, P=0.042), vancomycin (χ 2=1.70, P=0.089), vasoactive medications (χ 2=3.74, P<0.001) and use of invasive mechanical ventilation (χ 2=4.81, P<0.001) were risk factors associated with the development of AKI in hip fracture patients. Multivariate logistic regression analysis showed that age ( OR=1.03, P<0.001), coronary heart disease ( OR=2.05, P=0.069), hemoglobin ( OR=0.88, P=0.050), blood creatinine ( OR=1.37, P=0.009), blood sodium ( OR=1.07, P=0.026), anion gap ( OR=1.09, P=0.028) and vasoactive medications ( OR=3.83, P=0.018) and the use of invasive mechanical ventilation ( OR=6.56, P<0.001) were independent predictors of the development of AKI in hip fracture patients with serious underlying diseases. The area under the curve of the nomogram prediction model constructed by the above 8 predictors was 0.789, and the calibration curve of the nomogram was close to the ideal diagonal. Decision curve analysis showed that the net benefit of the model was significant. Conclusion:The incidence of AKI is high in hip fracture patients with serious underlying diseases. Age, coronary heart disease, hemoglobin, serum creatinine, serum sodium, anion gap, vasoactive drugs, and invasive mechanical ventilation can predict the occurrence of AKI to a certain extent. Combined with the risk factors, the construction of the corresponding prediction model can predict and manage the diagnosis and treatment of AKI in patients with hip fracture complicated with severe underlying diseases.

Objective:To investigate the early effects of cup in cup technique in reconstructing paprosky III acetabular bone defect in revision hip arthroplasty.Methods:From January 2017 to December 2019, a total of 20 cases (20 hips) with paprosky III acetabular bone defect were reconstructed by Cup-in-Cup technique, including 9 males and 11 females. The age ranged from 45 to 76 years, with an average of 64.6 years. The causes of revision were aseptic loosening of prosthesis in 17 cases and loosening of prosthesis caused by periprosthetic infection in 3 cases. There were 13 hips with acetabular bone defect of paprosky IIIA and 7 hips with paprosky IIIB. The acetabular side was repaired in 13 cases, and the acetabulum and femoral side were repaired in 7 cases at the same time. Harris hip score was used to evaluate hip function during postoperative follow-up. The occurrence of serious complications such as intraoperative vascular and nerve injury, postoperative prosthesis dislocation, periprosthetic infection and fracture were counted. The height and horizontal position of hip rotation center were measured by X-ray film.Results:The operation duration was 110±25 min (range 80-180 min) and intraoperative bleeding was 700±180 ml. All cases were followed up for 12-36 months, with an average of 18 months. At the last follow-up, the Harris hip score of 16 cases was more than 80, with excellen in 2 cases, good in 14 cases and fair in 4 cases. The Harris score was 84.3±7.5, which was significantly higher than that before operation 40.1±16.6 ( t=15.34, P<0.001). The height of hip joint rotation center on the affected side decreased from 34.2± 3.3 mm before operation to 18.6±2.8 mm after operation with significant difference ( t=15.11, P<0.001). The horizontal distance increased from 18.1±5.5 mm before operation to 26.2±7.3 mm after operation with significant difference ( t=-5.95, P<0.001). After operation, the height of hip joint rotation center on the affected side was slightly higher than that on the opposite side, with a significant difference between the affected side 18.6±2.8 mm and the opposite side 12.2±3.3 mm ( t=6.73, P=0.018). The horizontal position was 26.2±7.3 mm, which had no significant difference compared with the contralateral 30.1±5.5 mm ( t=-3.29, P=0.381). There was no vascular and nerve injury, periprosthetic infection or incision related complications. During the following-up, the prosthesis was in satisfied position without prosthesis or screw loosening and fracture. Conclusion:The reconstruction of paprosky III acetabular bone defect with Cup-in-Cup technique in revision hip arthroplasty can obtain satisfied early effects, with achieving relatively normal hip rotation center and initial stability.

Objective:To compare the diagnostic efficiency of colloidal gold dipstick method (PTH dipstick method) with that of doctors’ experience method based on nano-carbon method for rapid identification of parathyroid gland in thyroidectomy of thyroid cancer.Methods:From March to July 2020, 90 patients underwent thyroid surgery in the Friendship Hospital, Capital Medical University participated in the experimental study, and 155 samples underwent empirical judgment, parathyroid dipstick and pathological examination. All operations were performed by senior specialists. SPSS statistics 17.0 software was used for statistical analysis.Results:Seventy-four cases of parathyroid gland confirmed by both pathology and empirical judgment, and 81 cases of non-parathyroid gland confirmed by pathology; 130 cases of parathyroid glands confirmed by both PTH dipstick method and pathology, and 22 cases of non-parathyroid glands confirmed by pathology. The accuracy rate of PTH dipstick method was 85.53% which was much higher than that of empirical judgment method (47.74%). The data were statistically significant ( χ2=49.14, P<0.05). The sensitivity of PTH method was 95.89%, the specificity of PTH method was 75.94%, and the Youden index was 0.7183. The sensitivity of empirical judgment method was 81.3%, the specificity of empirical judgment method was 47.74%, and the Youden index was 0.2904. Conclusions:The diagnostic efficiency of the PTH method is higher than that of empirical judgment method to identify parathyroid gland in thyroid surgery. The two methods can be used together to increase the protection of parathyroid gland during operation.

Objective: To explore the application effect of fine needle aspiration cytology and sentinel lymph nodes stain assisted by contrast-enhanced ultrasound in early breast cancer. Methods: A patient with early breast cancer enrolled in Beijing Friendship Hospital, Capital Medical University received fine needle aspiration cytology assisted by contrast-enhanced ultrasonography and the sentinel lymph nodes were stained with blue dye before a standard sentinel lymph nodes biopsy traced with indocyanine green. The axillary status accessed by these two methods were compared. Results: Three sentinel lymph nodes were found and aspirated assisted by contrast-enhanced ultrasonography. Seven sentinel lymph nodes were obtained in sentinel lymph nodes biopsy surgery. All of these sentinel lymph nodes were negative. The stained sentinel lymph nodes could be recognized and dissected in open lymph nodes biopsy surgery. Conclusions Fine needle aspiration cytology assisted by contrast-enhanced ultrasonography could be a substitute for open sentinel lymph nodes biopsy. More related researches should be carry out to further compare these two methods.

Objective: To evaluate the efficacy of radiofrequency ablation in breast-conserving surgery followed neoadjuvant chemotherapy. Methods: Retrospective analysis of 30 cases of breast cancer patients admitted to Beijing Friendship Hospital, Capital Medical University from April 2015 to September 2018. The average age was 54.3 years and the range was 28 to 70 years. For breast invasive ductal cancer, patients underwent breast-conserving surgery after neoadjuvant chemotherapy, and then received radiofrequency ablation. The clinical and pathological characteristics, postoperative complications, recurrence and metastasis, and cosmetic effects were observed. Results: All 30 patients with breast-conserving surgery successfully completed radiofrequency ablation. The average outpatient follow-up was 22.5 months, ranging from 2 to 43 months, without local recurrence or metastasis; skin burns occurred in 2 cases (6.67%), and solid nodules formed in situ in 6 cases (20.00%); cosmetic satisfaction rate was 86.67% (26/30). Conclusions The radiofrequency ablation techniques applied in breast-conserving surgery have a high rate of technical success with relative low complication rates. And the radiofrequency ablation techniques may improve the cosmetic results after breast-conserving surgery and enhance local control.

Objective:To explore the application of radiofrequency ablation in breast conserving surgery with breast carcinoma.Methods:With retrospective research methods, a total of 230 patients who were treated with radiofrequency ablation after breast conserving surgery in Beijing Friendship Hospital, Capital Medical University from January 2016 to September 2018 were selected, patients were all females, the median age was 56 yecers, ranged from 27 to 91 years, and the postoperative efficacy, patients′ satisfaction with their appearance and complications were outpatient follow-up.Results:Follow-up for 18 months showed that 2 (0.87%) patients had postoperative recurrence and metastasis, 217 (94.35%) patients were satisfied with the postoperative breast appearance, and 8 patients (3.48%) had skin burns and in- situ sclerosing. Conclusions:Radiofrequency ablation is used in breast conserving surgery, which is simple to operate and has a low incidence of complications. It can strengthen local tumor control and improve the cosmetic effect of breast after conserving surgery, worthy of clinical promotion.

Objective:To understand the duration of survival and related influencing factors of HIV/AIDS patients in Liuzhou city.Methods:Both life table method and Kaplan-Meier method were used to calculate the average survival time of HIV/AIDS patients aged ≥15 years reported in Liuzhou city from 2008 to 2018. Factors related to the duration of HIV/AIDS patients were analyzed by univariate and multivariate Cox regression models.Results:A total of 14 856 patients with HIV/AIDS were involved in this study and with the average duration of survival time as 98.74 (95 %CI: 97.73-99.75) months. The cumulative survival rates of 1, 3, 5 and 10 years were 77.0%, 72.0%, 68.0%, 61.0% respectively. Results from the multivariate Cox proportional risk regression analysis showed that factors as sex, level of education, age when HIV infection was confirmed, occupation, route of transmission, source of samples, results of the first CD 4 test and antiviral treatment were all related to the duration of survival to the HIV/AIDS patients. Conclusions:Strategies involving early detection of HIV infection, improvement of the CD 4 initial detection rate and early antiviral treatment will help to significantly reduce the risk of death in HIV/AIDS population. Focus should be on male, middle-aged and elderly (over 41 years old), junior high school education or below farmers and migrant worker populations.

Objective To analyze the clinical efficacy of the laparoscopic breast-conserving surgery combined with radiofrequency ablation to treat the early-stage breast cancer.Methods We collected 55 patients diagnosed early-stage breast cancer in retrospect,which started from January 2014 to December 2016.Twenty-seven of them were performed the laparoscopic breast-conserving surgery combined with radiofrequency ablation while others went through laparoscopic breast-conserving surgery without radiofrequency ablation.Meanwhile,we adopted the student t-test and the chi-square test to compare results of two groups.More specific,the main indexes of this study are including the post-operative local recurrence,the incidence of fat liquefaction or the incision-infection,operation time,post-operative hospital stay and the hospitalization expense.Results The laparoscopic breast-conserving surgery combined with radiofrequency ablation group had low local-recurrence than the laparoscopic breastconserving surgery group (0 and 7.69％).Additionally,there were no statistical differences between two groups in the incidence of fat liquefaction.However,The laparoscopic breast-conserving surgery combined with radiofrequency ablation group had more hospitalization expense than the laparoscopic breast-conserving surgery group [(4.1 ± 0.7) ten thousand yuan and (2.3 ± 0.6) ten thousand yuan,P ＜ 0.05].Conclusions Although the laparoscopic breast-conserving surgery combined with radiofrequency ablation group remarkably increased the hospitalization expense because of the utility of the radiofrequency ablation related apparatus,it may provide the probability of shaving more residual tumor cell and may low down the recurrence,especially not rising up the incidence of the post-operative fat liquefaction.Therefore,this surgery method might be one of the potential developments in the minimal-invasive of early stage breast cancer.