BACKGROUND:Bipolar femoral head prosthesis has achieved the desired repair effect in patients with femoral neck fracture, but there is stil much controversy on the biomechanical properties of bipolar artificial femoral head prosthesis. OBJECTIVE:To compare biomechanical properties of the bipolar femoral head prosthesis replacement and internal fixation in the repair of femoral neck fracture in the elderly. METHODS:Twenty-three (46 sides) senile femoral neck fracture specimens were analyzed and randomized into internal fixation group(n=23)and bipolar femoral head prosthesis replacement group (n=23). Specimens in the internal fixation group underwent conventional metal implant fixation. Specimens in the bipolar femoral head prosthesis replacement group underwent bipolar femoral head prosthesis replacement. Mechanical properties of femoral prosthesis stem were tested on universal testing machine. Biomechanical properties after bipolar femoral head prosthesis replacement and internal fixation were compared. RESULTS AND CONCLUSION:(1) The maximum loadwassignificantly higher in the bipolar femoral head prosthesis replacement group than in the internal fixation group (P< 0.05). The maximum load trend images showed that the maximum load was significantly higher in the bipolar femoral head prosthesis replacement group than in the internal fixation group (P< 0.05). (2) The displacement in axial pul test was significantly shorter in the bipolar femoral head prosthesis replacement group than in theinternal fixation group (P< 0.05). The displacement trend images exhibited that the displacement in axial pul test was significantly shorter in the bipolar femoral head prosthesis replacement group than in the internal fixation group (P< 0.05). (3) These findings suggest that compared with the implant, bipolar femoral head prosthesis replacement in the repair of femoral neck fracture in the elderly is more stable, has better repair effects, can elevate hip function and obtain good initial stability.

f miRNAs had enhanced effects on the proliferation and apoptosis of pancreatic cancer cell than any single miRNA transfection.

Objective To investigate the opportunity and skill of surgery for pancreatic sinistral portal hypertension.Methods Clinical data were retrospectively analyzed on 15 cases of pancreatic sinistral portal hypertension admired from Dec 2015 to Dec 2017.Results All fiften cases underwent surgical treatment,among them three cases were initially treated conservatively in the early stage and treated surgically for gastrointestinal bleeding,12 cases with definite pancreatic disease and pancreatic sinistral portal hypertension treated in the first stage.Three patients underwent second surgery for recurrent gastrointestinal bleeding.The patients were followed up for 6 to 18 months with symptoms significantly impioved without deaths.Conclusions Splenectomy combined with esophagogastric devascularization is the basic surgical treatment for pancreatic sinistral portal hypertension.

Objectives:The COVID-19 epidemic has swept all over the world. Estimates of its case fatality rate were influenced by the existing confirmed cases and the time distribution of onset to death, and the conclusions were still unclear. This study was aimed to estimate the age-specific case fatality rate of COVID-19.Methods:Data on COVID-19 epidemic were collected from the National Health Commission and China CDC. The Gamma distribution was used to fit the time from onset to death. The Markov Chain Monte Carlo simulation was used to estimate age-specific case fatality rate.Results:The median time from onset to death of COVID-19 was M=13.77 ( P25- P75: 9.03-21.02) d. The overall case fatality rate of COVID-19 was 4.1 % (95 %CI: 3.7 %-4.4 %) and the age-specific case fatality rate were 0.1 %, 0.4 %, 0.4 %, 0.4 %,0.8 %, 2.3 %, 6.4 %, 14.0 and 25.8 % for 0-, 10-, 20-, 30-, 40-, 50-, 60-, 70- and ≥80 years group, respectively. Conclusions:The Markov Chain Monte Carlo simulation method adjusting censored is suitable for case fatality rate estimation during the epidemic of a new infectious disease. Early identification of the COVID-19 case fatality rate is helpful to the prevention and control of the epidemic.