Objective To establish the three-dimensional (3D) finite element model of the knee joint including posterolateral complex (PLC), and to simulate the reconstruction biomechanical analysis in this model. Methods The knee of a 26-year-old healthy man was scanned by MRI to obtain the image data of the knee in the coronal, sagittal, and axial position. First, Mimics10.01 and Hyperworks 8.0 softwares were used to extract each slice profile data of the knee joint in a two-dimensional image data respectively and to establish 3D geometric model of bone, meniscus, articular cartilage, and ligament. Second, Unigraphics software NX 4.0 was used to establish a 3D finite element model of knee joint, which had the functions of Mesh, material properties, component connection, and contact definition. Third, displacement measurement on the model and reconstructing biomechanical analysis for PLC simulation were performed. Results The 3D finite element model of the knee joint including PLC was established successfully. Under 134 N forward force, the tibia forward displacement was 4.83 mm. PLC simulation reconstruction biomechanical analysis of the 3D finite element model of the knee joint showed that under 10 N·m varus and external rotation torque conditions, the knee varus and external rotation angles of simulation reconstruction were greater than those of the intact knee, and less than those of PLC missing. Conclusion The 3D finite element model of the knee joint including PLC can be established by the reverse engineering, and it is valid and can be used as the basis for the biomechanical properties to analog reconstruction of PLC.
The choice of genetic models was main difficulty in the meta-analysis of gene-disease association studies. In this study, we made a further discussion about the genetic model-free approach that proposed by Minelli et al. The program that coded by JAGS and R was carried out to perform the Bayesian procedure. In a real example, several kinds of prior distribution were used, including non-informative prior distribution and external clinical prior information. Especially, compared to Minelli’s study, we introduced clinical prior information. The results indicated that the pooled results were rather robust no matters the prior distribution were non-informative or informative, especially when the number of included studies were large.
目的:探討蛻皮甾酮對胰島素抵抗(IR)HepG2細胞胰島素受體底物(IRS)蛋白表達的影響。方法:胰島素抵抗HepG2細胞模型建立后,培養液中加入蛻皮甾酮共同孵育,觀察蛻皮甾酮及吡格列酮對模型細胞葡萄糖摻入率的影響;應用免疫細胞化學染色法等方法觀察蛻皮甾酮對胰島素抵抗HepG2細胞IRS-1、IRS-2表達的影響。結果:與模型細胞組比較,1×10-5mol/L蛻皮甾酮可使IR HepG2細胞IRS-1、IRS-2蛋白的表達顯著增加。結論:蛻皮甾酮的胰島素增敏作用可能與胰島素信號轉導分子IRS-1、IRS-2蛋白的表達增強有關。
Abstract: The hybrid pencil beam model (HPBM) is an effective algorithm for calculating electron dose distribution in radiotherapy. The mean energy distribution of incident electron beam in phantom is one of the factors that affect the calculation accuracy of HPBM, especially in field edge areas near the end of the electron range. A new fitted formula based on Monte Carlo (MC) simulation data for electron beams with energy range of 6-20MeV in the homogeneous water phantom is proposed in this paper. The precision of the fitted formula within the scope of the energy was evaluated by comparing the electron dose distribution of ECWG measured data with that obtained from HPBM which took the mean electron energy that calculated by the fitted formula and the existed empirical formula, respectively. The results showed that the accuracy of dose distribution that obtained by the mean electron energy calculated with the fitted formula increased about 1%.
Objective To observe the pathological and functional changes of retinal photochemical damages exposed to green flurescent light. Methods The Sprague Dawley rats were continually exposed to green fluorescent light with an illuminancem level of (1 900plusmn;106.9) Lx for 24 hours.The changes of retinal morphology and morphometrics and flash electroretinogram were studied before light exposure and at the 6th hour,6th day and 14th day after light exposure. Results At the 6th hours after light exposure,the outer nuclear layer(ONL)of retina becoma thinner compared with that bfore light exposure.The thickness of ONL decreased by 23.91% and the inner and outer segments appeared disorderly arranged.At the 6th day after light exposure the thickness of ONL is thinner than that at the6th hour,i.e.decreased by 46.6%. At the 14th day after light exposure the thickness of ONL decreased by 42.40%.Flash electroretinogram showed that the amplitudes of a and b wave decreased continuously at the 6th hour and 6th day and unrecovered at the 14th day after light exposure. Conclusion This model might be an ideal one for research on retinal photochemical damage. (Chin J Ocul Fundus Dis,1998,14:101-103)
【Abstract】 Objective To investigate both incidence and mechanism attributing to steroid-associated osteonecrosisof femoral head(ONFH) using an experimental protocol with a single low-dose l i popolysaccharide (LPS) injection andsubsequently three injections of high-dose methylprednisolone (MPS). Methods Twenty-five New Zealand white rabbits with body weight of (3.0 ± 0.3) kg were divided randomly into 2 groups. In treatment group, 19 rabbits received one intravenous injection of LPS (10 μg/kg); 24 hours later, three injections of 20 mg/kg of MPS were given intramuscularly at an interval of 24 hours. Additional 6 rabbits which received normal sal ine injection at the same time point were used as controls(control group). The blood samples were collected for hematological examinations before and after LPS injection, MRI was performed on bilateral hip six weeks after last MPS injection, meanwhile, bone marrow was aspirated from femoral head region to evaluate stem cell’s activity. Bilateral femoral heads were harvested to make histopathology examination. Results All animals survived throughout the experiment period except one death on the second day after LPS injection. In the histopathological examinationfor the femoral head, ONFH+ was observed in 16 rabbits (88.9%), and the lesions were mainly in the metaphysis. In ONFH+ rabbits, micro vessels fibrous thrombosis and extravascular marrow fat cell size increasing were found around necrotic bone; The femoral heads of control group had no changes. MRI accurate ratio was 93.8% (15/16). Compared to basel ine, a significant decrease in ratio of tissue plasminogen activator/plasminogen activator inhibitor 1 and activated partial thromboplatin time, and a significant increase in ratio of low-density l ipoprotein/high-density l ipoprotein were only found in ONFH+ rabbits (P lt; 0.05). Meanwhile there was a significant decrease in the number of CFU-F (8.50 ± 9.63) compared with the control (70.17 ± 7.78, P lt; 0.05). Conclusion A single low-dose LPS injection and subsequent three injections of high-dose MPS is effective on building steroid-associated ONFH model, coagulation and l ipometabol ism abnormal ity, activity degeneration of stem cell may be the key factors of ONFH.
Objective To conduct a systematic review of the construction methods, predictive factors, and model quality of risk prediction models for postoperative chronic pain in knee replacement surgery patients, providing evidence for the development of nursing-sensitive dynamic prediction models. Methods A systematic review of risk prediction models for postoperative chronic pain in knee replacement surgery patients was conducted by searching PubMed, Web of Science, Cochrane Library, CINAHL, SinoMed, CNKI, Wanfang Database, and VIP Database. The search period was from the establishment of the databases to February 28, 2025. Two researchers independently screened the literature, extracted data, and assessed the risk of bias and applicability of the included studies. Results A total of 10 studies involving 10 predictive models were included in this review. Among these, three models underwent internal validation, and one model underwent external validation. Commonly reported predictive factors included postoperative 24-hour Numerical Rating Scale scores, postoperative knee function scores, sleep disorders, preoperative depression, postoperative functional exercises, postoperative complications, preoperative pain, and postoperative C-reactive protein levels. All 10 studies had a high risk of bias and were generally applicable. Conclusions Existing risk prediction models generally rely on static indicators and lack dynamic monitoring of postoperative rehabilitation behaviors and psychosocial factors, with severe deficiencies in model validation. Future research should focus on developing nursing-led multidimensional dynamic models that incorporate functional exercise adherence data collected via wearable devices, standardize external model validation, and enhance clinical translation value.
【摘要】 目的 用老年大鼠建立一種與人類發病年齡相符的穩定可重復的急性心肌梗死動物模型。 方法 Wistar大鼠經戊巴比妥鈉麻醉后，氣管切開插管，連通呼吸機，開胸后結扎左冠狀動脈前降支。分不同時間點測血流動力學后取出心臟行病理組織學觀察。 結果 成功建立老年大鼠心肌梗死模型并進行病理組織學驗證。 結論 建立老年大鼠心梗模型是可靠的，有助于指導臨床實踐。【Abstract】 Objective To develop a steady and repeatable acute myocardial infarction model in old rats in accordance to human age. Methods Wistar rats were anaesthetized with sodium phenobarbital. After tracheotomy intubation, respiration machine was linked. Left anterior thoracotomy was performed to ligate the left anterior descending coronary artery. After hemodynamic parameters were obtained at various time points, hearts of the rats were taken for pathologic and histological examinations. Results The model of acute myocardial infarction in old rats was established successfully and proved by pathologic and histological staining. Conclusion It is reliable to establish the myocardial infarction model in old rats, which is helpful in guiding clinical practices.