A dynamic model of simulating stress distribution in the distal femur after total knee replacement

The aim of this study has been to develop a dynamic model of the knee joint after total knee replacement (TKR) to analyse the stress distribution in the distal femur during daily activities. Using MSC/ADAMS and MSC/MARC software, a dynamic model of an implanted knee joint has been developed. This model consists of the components of the knee prosthesis as well as the bones and ligaments of the knee. The femur, tibia, fibula, and patella have been modelled as mixed cortico-cancellous bone. The distal part of femur has been modelled as a flexible body with springs used to simulate the ligaments positioned at their anatomical insertion points. With this dynamic model a gait cycle was simulated. Stress shielding was identified in the distal femur after TKR, which is consistent with other investigators' results. Interestingly, higher stresses were found in the bone adjacent to the femoral component peg. This dynamic model can now be used to analyse the stress distribution in the distal femur with different load conditions. This will help to improve implant designs and will allow comparison of prostheses from different manufacturers.     

基于模拟惯量的电梯永磁同步曳引机上行超速保护装置检测系统

提出了一种基于模拟惯量的电梯永磁同步曳引机上行保护装置的检测系统。该检测系统以曳引机综合性能测试平台为基础．利用飞轮模拟电梯的惯量,利用直流电动机模拟负载．可在电梯安装前完成电梯上行超速保护装置的测试工作。实际测试表明,该方法符合电梯型式试验规则的要求。测试结果高效、准确和可靠。     

Force interactions between substrates and SPM cantilevers immersed in fluids

With the availability of equipment used in Scanning Probe Microscopy (SPM), researchers have been able to probe the local fluid–substrate force interactions with resolutions of pN using a variety of SPM cantilevers. When using such methods, it is essential to differentiate between contributions to the net force on the cantilever. Specifically, the interaction between the cantilever, substrate and fluid, quantified while generating force curves, are discussed and compared with theoretical models for squeeze-film effects and drag on the SPM cantilevers. In addition we have demonstrated a simple method for utilizing the system as a micro-viscometer, independently measuring the viscosity of the lubricant for each test.     

Involvement of human intracisternal A-type retroviral particles in autoimmunity

Prior studies have linked retroviruses to various arthropathies and autoimmune diseases. Sj?gren's syndrome (SS), a systemic autoimmune disease, is characterized by aggressive infiltration of lymphocytes into the salivary and lacrimal glands, resulting in destruction of the glands and dry mouth and eyes (sicca syndrome). The infiltrating lymphocytes in SS may become overtly malignant, and thus, the incidence of lymphoma is greatly increased in SS patients. A human intracisternal A-type retroviral particle type I (HIAP-I) has been isolated from persons with SS. HIAP-I shares a limited number of antigenic epitopes with human immunodeficiency virus (HIV), but is distinguishable from HIV by morphological, physical, and biochemical criteria. A substantial majority of patients with SS or systemic lupus erythematosus (SLE) have serum antibodies to the proteins of this human retrovirus. Fewer than 3% of the normal blood donor population have antibodies to any HIAP-associated proteins. A second type of a human intracisternal A-type retrovirus, HIAP-II, was detected in a subset of patients with idiopathic CD4 lymphocytopenia (ICL), an AIDS-like immunodeficiency disease. Most HIAP-II positive ICL patients were also antinuclear antibody positive. Reviewed here are additional studies from several laboratories suggesting that HIAP or related viruses may be involved in SLE and other autoimmune conditions. Additionally, results of comprehensive surveys of autoimmune patients to determine seroreactivity to HIAP, and other human retroviruses, including HIV and human T-lymphotropic virus type I, are reported.     

Anti-Inflammatory Therapeutic Approaches to Prevent or Delay Post-Traumatic Osteoarthritis (PTOA) of the Knee Joint with a Focus on Sustained Delivery Approaches

Inflammation plays a central role in the pathogenesis of knee PTOA after knee trauma. While a comprehensive therapy capable of preventing or delaying post-traumatic osteoarthritis (PTOA) progression after knee joint injury does not yet clinically exist, current literature suggests that certain aspects of early post-traumatic pathology of the knee joint may be prevented or delayed by anti-inflammatory therapeutic interventions. We discuss multifaceted therapeutic approaches that may be capable of effectively reducing the continuous cycle of inflammation and concomitant processes that lead to cartilage degradation as well as those that can simultaneously promote intrinsic repair processes. Within this context, we focus on early disease prevention, the optimal timeframe of treatment and possible long-lasting sustained delivery local modes of treatments that could prevent knee joint-associated PTOA symptoms. Specifically, we identify anti-inflammatory candidates that are not only anti-inflammatory but also anti-degenerative, anti-apoptotic and pro-regenerative.     

Estimation of free-swelling index based on coal analysis using multivariable regression and artificial neural network

The effects of proximate, ultimate and elemental analysis for a wide range of American coal samples on Free-swelling Index (FSI) have been investigated by multivariable regression and artificial neural network methods (ANN). The stepwise least square mathematical method shows that variables of ultimate analysis are better predictors than those from proximate analysis. The non linear multivariable regression, correlation coefficients (R²) from ultimate analysis inputs was 0.71, and for proximate analysis input variables was 0.49. With the same input sets, feed-forward artificial neural network (FANN) procedures improved accuracy of predicted FSI with R² = 0.89, and 0.94 for proximate and ultimate analyses, respectively. The ANN based prediction method, as a first report, shows FSI is a predictable variable, and ANN can be further employed as a reliable and accurate method in the free-swelling index prediction.     

镀锌设备土酸清洗缓蚀剂JL-1的研制与评价

通过单组分缓蚀剂对锌的缓蚀作用和多组分之间的协同效应研究,确定了具有最佳缓蚀效果的缓蚀组分的组合,用正交实验方法获得了缓蚀组分之间最佳配比,研制出一种高效镀锌设备土酸清洗缓蚀剂JL-1,并对其缓蚀性能进行了评价。失重法研究结果表明,该缓蚀剂缓蚀率可高达99.9%以上,且具有良好的抗干扰性能。电化学研究结果表明,缓蚀剂JL-1是一种混合型缓蚀剂,缓蚀剂JL-1使锌的腐蚀电流明显减小。     

Mammalian Exocrine Secretions XI. Constituents of the Preorbital Secretion of Klipspringer, Oreotragus oreotragus

The ketones 3-pentanone, 4-methyl-2-pentanone, 5-methyl-3-hexanone, 4-methyl-3-hexanone, and the esters ethyl propanoate, 2-methylpropyl acetate, ethyl 3-methylbutanoate, and 2-methylpropyl propanoate were identified as the only volatile organic constituents of the preorbital secretion of the klipspringer, Oreotragus oreotragus. These compounds are considerably more volatile than those found in the preorbital secretions of other antelopes belonging to the tribe Antelopini. More than 50% of the preorbital secretion consists of proteinaceous material, which probably acts as a controlled-release substance in retarding the evaporation of the volatile constituents of the secretion from territorial marks.