The mechanical model of knee is a system of constructional elements with specific restrains and material properties, which are deduced from the components of knee based on their functions and junctions. Kinematics and kinetics of knee can be calculated from the mechanical model. A review of some mechanical models of knee are shown in this paper.
Biomechanical Phenomena ; Computer Simulation ; Humans ; Knee Joint ; physiology ; Models, Biological ; Range of Motion, Articular ; physiology ; Stress, Mechanical

Objective To assess the neurophysiological effects of transcranial direct current stimulation (tDCS) of the motor cortex when swallowing.Methods Twenty healthy volunteers had anodal tDCS (a-tDCS), cathodal tDCS (c-tDCS) or sham tDCS applied over the hemisphere with stronger suprahyoid projections, effortful swallowing was performed simultaneously.Suprahyoid motor-evoked potentials (MEPs) on both the stimulated and non-stimulated contra-lateral hemisphere were examined immediately before stimulation and 5,30, 60 and 90 minutes later.The MEPs were normalized and analyzed using two-way repeated measures analysis of variance.Results The tDCS had long-lasting effects on the suprahyoid MEPs bilaterally.There were significant changes in the effect over time.Sham tDCS showed no significant effect.Compared with sham tDCS, a-tDCS significantly increased the excitability of the stimulated hemisphere, but not the non-stimulated projection.Compared with sham tDCS, c-tDCS induced decreased cortical excitability in the stimulated hemisphere but an increase in the non-stimulated projection.Conclusions tDCS during swallowing can alter bilateral swallowing activity in the motor cortex in a polarity-dependent and site-dependent way.A-tDCS enhances the excitability of the stimulated hemisphere while c-tDCS inhibits it ipsilaterally but increases it contralaterally.

A sagittal plane model of knee joint based on crossed-four-bar-linkage-based tibiofemoral joint model has been developed using geometric and force equilibrium constraints. The model predicts and explains the movement of contact point on the patella and femur, variation of patellar and patellar tendon angle, variation of patellar mechanism angle and variation of patellofemoral contact force and patellar tendon force. The computed results agree well with the published experimental results.
Biomechanical Phenomena ; Humans ; Knee Joint ; anatomy & histology ; physiology ; Models, Biological ; Movement ; physiology ; Patella ; anatomy & histology ; physiology

Resorption and osteolysis of periimplant bones resulting from the wear debris of artificial joint will cause long-term loosening. A new type of rolling knee artificial joint without UHMWPE based on the mechanics of rolling friction is designed for alleviating this problem. Because of low friction force, the resistance of extension and flexion is reduced strikingly and the stress on the interface between prosthesis and bone is reduced evidently. In addition, the bio-toxicity caused by the wear debris of UHMWPE will not occur absolutely. In consequence, the rolling artificial joint can prevent the trend of long-term loosening of the prosthesis efficiently.
Animals ; Arthroplasty, Replacement, Knee ; Ceramics ; chemistry ; Computer-Aided Design ; Dogs ; Humans ; Knee Prosthesis ; Materials Testing ; Polyethylenes ; Prosthesis Design ; Vitallium ; chemistry

A novel method for the design of hip joint prostheses based on X-ray films is introduced. Only arcs and straight-lines form figures of hip joint prostheses. Because geometrical tolerances of manufacturing hip joint prostheses matching section are usually not strict, hip joint prostheses can be manufactured without CNC machine tool. Three hip joint prostheses for three different femurs were designed through a program which was developed by the present authors. Approximate marrow cavities of these femurs were simulated according to a standard database about femur. These models of femur marrow cavities were used to verify the hip joint prostheses designed. These hip joint prostheses designed were manufactured and implanted into femurs respectively. Experimental results indicate that the novel method for the design of hip joint prostheses is practicable.
Computer-Aided Design ; Hip Joint ; diagnostic imaging ; Hip Prosthesis ; Humans ; Prosthesis Design ; methods ; Tomography, X-Ray Computed

Bipolar affective disorder refers to a category of mood disorders characterized clinically by the presence of both manic or hypomanic episodes and depressive episodes.Lithium stands out as the primary pharmacological intervention for managing bipolar affective disorder.However,its therapeutic dosage closely approaches toxic levels.Toxic symptoms appear when the blood lithium concentration surpasses 1.4 mmol/L,typically giving rise to gastrointestinal and central nervous system reactions.Cardiac toxicity is rare but serious in cases of lithium poisoning.The study reports a case of a patient with bipolar affective disorder who reached a blood lithium concentration of 6.08 mmol/L after the patient took lithium carbonate sustained-release tablets beyond the prescribed dosage daily and concurrently using other mood stabilizers.This resulted in symptoms such as arrhythmia,shock,impaired consciousness,and coarse tremors.Following symptomatic supportive treatment,including blood dialysis,the patient's physical symptoms gradually improved.It is necessary for clinicians to strengthen the prevention and recognition of lithium poisoning.

【Objective】 To study the incidence and specificity of platelet antibody in blood donors in Suzhou, analyze the distribution characteristics of platelet antibody in blood donors in this area, and explore the significance of platelet antibody detection in blood donors to reduce the adverse reactions toplatelet transfusion in clinical. 【Methods】 Platelet antibody detection was performed in 2178 blood donors in this area by solid-phase immunosorbent assay. The antibody specificity of the positive samples was analyzed by commercial kit, and the anti-CD36 antibody positive samples were further identified by flow cytometry and gene sequencing. 【Results】 Twelve positive samples were detected by platelet antibody screening, with a positive rate of 0.55%(12/2 178), including 5 males (0.33%, 5/2 178)and 7 females(1.06%, 7/2 178). Among the positive samples, anti-HLA-Ⅰ antibody was identified in 2 cases, anti-CD36 antibody in 1 case, and the antibody specificity was not identified in the other 9 cases. In one case, the positive rate of anti-HLA-Ⅰ antibody PRA was 31.31%(31/ 99), which was mainly specific to anti-B15, anti-B35 and anti-B40. The positive rate of anti-HLA-Ⅰ antibody PRA in the other case was 45.45%(45/ 99), which was mainly specific to anti-A2, anti-A11, anti-A24, anti-A29, anti-A33, anti-A66, anti-B15 and anti-B35. The blood donor with anti-CD36 antibody was type I CD36 deficiency, and 329_330delAC mutation occurred in exon 5. 【Conclusion】 Through antibody screening and specificity identification, the positive rate of platelet antibody in females was significantly higher than that in males(P<0.05). In addition to the common anti-HLA-I antibodies, anti-CD36 antibody was also detected in type I CD36 deficient blood donor. Therefore, the detection of platelet antibodies in blood donors is of certain clinical significance to reduce the adverse reactions to blood transfusion caused by antibodies in platelet products.

【Objective】 To investigate the expression of CD36 antigen in Suzhou area, analyze the type of antigen deficiency and gene mutation, so as to provide references for the establishment of CD36 negative donor registry in Suzhou. 【Methods】 Anticoagulant whole blood samples (805 cases) were randomly collected from healthy blood donors in Suzhou Blood Center. The expression of CD36 antigen on platelet and monocyte was analyzed by flow cytometry to determine the type of CD36 deficiency. The gene mutation type of platelet CD36 antigen-deficient was performed by genomic DNA sequencing. 【Results】 The CD36 deficiency frequency on platelet was 2.48% (20/805), among which TypeⅠ(lacking CD36 expression both on platelet and monocyte) and TypeⅡ(lacking CD36 expression on platelet only) CD36 deficiency accounted for 10% (2/20) and 90% (18/20), respectively. CD36 gene mutations were found in 10 samples, including 3 cases of 329_330 d^elAC, 1 case of 1228_1239 d^elATTGTGCCTATT and 2 cases of 1163 A>T; 1 case of 329_330 d^elAC+ 1172_1183 d^elTATTGGTCAAGC and 287 G>C+ 329_330 d^elAC heterozygous mutation. In addition, 1 case of 745 A>G and 1 case of 806 C>T mutations were novel, and not yet reported. 【Conclusion】 Results showed that the frequency of CD36 antigen deficiency in Suzhou were similar to that reported in southern China, but the mutation sites were slightly different. The establishment of CD36 negative platelet registry could provide negative platelets for patients with transfusion reactions caused by anti-CD36 antibody and improve the effect of clinical platelet transfusion.