Objective To study the effects of porous prothesis with radial gradient and homogenized structures on stress transmission in the tibia by using finite element method.Methods Based on the reverse engineering technology,the tibial model was constructed,and the bionic trabecular bone structure prosthesis with gradient change of pore edge diameter and the homogeneous bionic trabecular bone structure prosthesis were designed.The Vicon dynamic capture platform was used to obtain the human gait and the axial force of the tibia-femoral joint during flexion,which was imported into ANSYS Workbench as a boundary condition for mechanical performance analysis.Results In the case of proximal defect,the von Mises stress of the bone for prosthesis with radial gradient structure was increased by 3.68 MPa,and that in the case of distal defect was increased by 7.34 MPa.Compared with the homogenized prosthesis,the von Mises stress of the proximal and distal defects was decreased by 171 MPa and 190.4 MPa,respectively.Conclusions The stress of the radial gradient structure prosthesis diffuses from the outside to the middle high porosity area along the prosthesis,which can effectively transfer the tibial plateau load,reduce stress concentration of the prosthesis,improve bone stress and prolong service life of the prosthesis.This study provides a theoretical reference for clinical prosthesis replacement.

Objective:To develop a Recurrence Fear Scale for Patients with Atrial Fibrillation after Catheter Ablation and conduct psychometric testing for its reliability and validity.Methods:Based on the common-sense model of self-regulation, the scale was developed through a literature review and semi-structured interviews to construct an item pool. The scale draft was formed through expert consultation and a pre-survey. Using convenience sampling, 361 patients with atrial fibrillation who had undergone catheter ablation and were either hospitalized or attending outpatient follow-up at the Department of Cardiology, Affiliated Hospital of Qingdao University, between January and March 2024, were selected for questionnaire survey. Item analysis and reliability and validity tests were performed on the scale.Results:Exploratory factor analysis identified five common factors, with a cumulative variance contribution rate of 74.375%. Confirmatory factor analysis showed good model fit. The final scale included five dimensions and 24 items: trigger factors, recurrence risk perception, disease uncertainty, psychological burden, and coping strategies. The content validity index at the scale level was 0.864, and the item-level content validity index ranged from 0.684 to 0.947. The Cronbach's α coefficient of the scale was 0.919, the split-half reliability coefficient was 0.834, and the test-retest reliability coefficient was 0.872.Conclusions:The development of the Recurrence Fear Scale for Patients with Atrial Fibrillation after Catheter Ablation is scientific and standardized, and the scale has good reliability and validity. It can effectively assess the level of recurrence fear in these patients.

Objective To study the effects of porous prothesis with radial gradient and homogenized structures on stress transmission in the tibia by using finite element method.Methods Based on the reverse engineering technology,the tibial model was constructed,and the bionic trabecular bone structure prosthesis with gradient change of pore edge diameter and the homogeneous bionic trabecular bone structure prosthesis were designed.The Vicon dynamic capture platform was used to obtain the human gait and the axial force of the tibia-femoral joint during flexion,which was imported into ANSYS Workbench as a boundary condition for mechanical performance analysis.Results In the case of proximal defect,the von Mises stress of the bone for prosthesis with radial gradient structure was increased by 3.68 MPa,and that in the case of distal defect was increased by 7.34 MPa.Compared with the homogenized prosthesis,the von Mises stress of the proximal and distal defects was decreased by 171 MPa and 190.4 MPa,respectively.Conclusions The stress of the radial gradient structure prosthesis diffuses from the outside to the middle high porosity area along the prosthesis,which can effectively transfer the tibial plateau load,reduce stress concentration of the prosthesis,improve bone stress and prolong service life of the prosthesis.This study provides a theoretical reference for clinical prosthesis replacement.

Objective:To develop a Recurrence Fear Scale for Patients with Atrial Fibrillation after Catheter Ablation and conduct psychometric testing for its reliability and validity.Methods:Based on the common-sense model of self-regulation, the scale was developed through a literature review and semi-structured interviews to construct an item pool. The scale draft was formed through expert consultation and a pre-survey. Using convenience sampling, 361 patients with atrial fibrillation who had undergone catheter ablation and were either hospitalized or attending outpatient follow-up at the Department of Cardiology, Affiliated Hospital of Qingdao University, between January and March 2024, were selected for questionnaire survey. Item analysis and reliability and validity tests were performed on the scale.Results:Exploratory factor analysis identified five common factors, with a cumulative variance contribution rate of 74.375%. Confirmatory factor analysis showed good model fit. The final scale included five dimensions and 24 items: trigger factors, recurrence risk perception, disease uncertainty, psychological burden, and coping strategies. The content validity index at the scale level was 0.864, and the item-level content validity index ranged from 0.684 to 0.947. The Cronbach's α coefficient of the scale was 0.919, the split-half reliability coefficient was 0.834, and the test-retest reliability coefficient was 0.872.Conclusions:The development of the Recurrence Fear Scale for Patients with Atrial Fibrillation after Catheter Ablation is scientific and standardized, and the scale has good reliability and validity. It can effectively assess the level of recurrence fear in these patients.

ObjectiveTo investigate the relationship between hyponatremia and degree of liver injury, complications and survival time, and the prognostic value of hyponatremia in patients with decompensated liver cirrhosis. MethodsA total of 218 patients who were diagnosed with decompensated liver cirrhosis for the first time in The First Affiliated Hospital of Dalian Medical University from January 2000 to March 2005 were enrolled in this study, and according to the serum sodium concentration, these patients were divided into group Ⅰ with a serum sodium concentration of ≥130 mmol/L (n=51), group Ⅱ with a serum sodium concentration of ≥120 and ＜130 mmol/L (n=97), group Ⅲ with a serum sodium concentration of ＜120 mmol/L (n=70). The patients′sex, age, serum sodium concentration, Child-Pugh class, and complications were analyzed, and the survival time was calculated. The one-way analysis of variance was applied for comparison of continuous data between groups, and the least significant difference t-test was applied for comparison between any two patients; the chi-square test was applied for comparison of categorical data between groups; the Kaplan-Meier method was applied for survival analysis, and the Cox regression model was applied for regression analysis. ResultsCompared with groups Ⅰ and Ⅱ, group Ⅲ had the highest proportion of patients with Child-Pugh C cirrhosis. With the increasing Child-Pugh score, the serum sodium concentration decreased; the serum sodium concentration showed significant differences across the patients with Child-Pugh A, B, and C cirrhosis (F=17.336, P＜0001), and differed significantly between any two groups of these patients (all P ＜0.05). Compared with groups Ⅰ and Ⅱ, group Ⅲ had the highest incidence rate of complications, and the incidence rates of hepatic encephalopathy and hepatorenal syndrome showed significant differences across the three groups (χ2=17.718 and 6.277, both P＜0.05). Group Ⅲ had a significantly shorter survival time than groups Ⅰ and Ⅱ (both P＜0.05). ConclusionIn patients with decompensated liver cirrhosis, the severity and incidence rate of hyponatremia increase significantly as liver injury becomes more severe, which suggests that hyponatremia can be used as a prognostic indicator in patients with decompensated liver cirrhosis.

Objective To explore in vitro the best time window for using sinusoidal electromagnetic fields to promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).Methods BMSCs were isolated and cultured from 4-week-old Sprague-Dawley rats (male and female,80-120g).The BMSCs (from passage 3) were exposed 0,1,4 or 8h/d for 7d,14,or 28d,respectively,to 15Hz sinusoidal electromagnetic fields with a maximum amplitude of lmT.Those exposed 0h/d served as the control.The relative expressions of runt related gene-2 (RUNX2),bone sialoprotein (BSP) and osteopontin (OPN) were determined using real-time,quantitative reverse transcription-polymerase chain reactions (RT-PCRs).The level of RUNX2 protein was determined by Western blotting after 14d.Alizarin red staining was used to compare calcium distribution in each group.Results Obvious promotion of differentiation to osteoblasts was observed after 7 days of exposure to the15 Hz sinusoidal electromagnetic fields,most obviously manifested by an outstanding increase of the early osteogenic index RUNX2 in those exposed 4h/d.After 14 days of intervention,the 1h/d exposure showed to be most effective,especially in inducing the changes of the late osteogenic index OPN.The trends of changes in RUNX2 protein were similar in all groups.After stimulating 1h/d for 14 and 28days,calcium deposition increased to the greatest extent.Conclusions Exposure to sinusoidal electromagnetic fields induces osteogenic differentiation to osteoblasts in rat BMSCs in vitro.There is an apparent window effect.The best results are observed with more days of exposure and shorter exposure time (1h) every day.