RESUMEN
Finite element studies of the tibiofemoral joint have increased use in research, with attention often placed on the material models. Few studies assess the effect of meniscus modelling assumptions in image-based models on contact mechanics outcomes. This work aimed to assess the effect of modelling assumptions of the meniscus on knee contact mechanics and meniscus kinematics. A sensitivity analysis was performed using three specimen-specific tibiofemoral models and one generic knee model. The assumptions in representing the meniscus attachment on the tibia (shape of the roots and position of the attachment), the material properties of the meniscus, the shape of the meniscus and the alignment of the joint were evaluated, creating 40 model instances. The values of material parameters for the meniscus and the position of the root attachment had a small influence on the total contact area but not on the meniscus displacement or the force balance between condyles. Using 3D shapes to represent the roots instead of springs had a large influence in meniscus displacement but not in knee contact area. Changes in meniscus shape and in knee alignment had a significantly larger influence on all outcomes of interest, with differences two to six times larger than those due to material properties. The sensitivity study demonstrated the importance of meniscus shape and knee alignment on meniscus kinematics and knee contact mechanics, both being more important than the material properties or the position of the roots. It also showed that differences between knees were large, suggesting that clinical interpretations of modelling studies using single geometries should be avoided.
Asunto(s)
Fémur , Análisis de Elementos Finitos , Meniscos Tibiales , Modelos Biológicos , Tibia , Humanos , Fémur/fisiología , Fémur/anatomía & histología , Fenómenos Biomecánicos , Tibia/fisiología , Tibia/anatomía & histología , Meniscos Tibiales/fisiología , Meniscos Tibiales/anatomía & histología , Menisco/fisiología , Menisco/anatomía & histología , Articulación de la Rodilla/fisiología , Articulación de la Rodilla/anatomía & histologíaRESUMEN
Carbon dots/Prussian blue nanoparticles (CDs/PBNPs) with fluorescence (FL) performance and peroxidase-like activity are synthesized by a simple two-step method. The FL of CDs/PBNPs can be effectively quenched by Fe3+. Fe3+ can accelerate the peroxidase-like activity of CDs/PBNPs. More excitingly, the peroxidase-like activity of CDs/PBNPs could be further enhanced due to the influence of the photothermal effect. Based on the FL property and enhanced peroxidase-like activity, a cascade strategy is proposed for detection of Fe3+ and free cholesterol. CD/PBNPs act as FL probe for detection of Fe3+. The enhanced peroxidase-like activity of CDs/PBNPs can also be used as colorimetric probe for the detection of free cholesterol. The detection ranges of Fe3+ and free cholesterol are 4-128 µM and 2-39 µM, and the corresponding limit of detections are 2.0 µM and 1.63 µM, respectively. The proposed strategy has been verified by the feasibility determination of Fe3+ and free cholesterol, suggesting its potential in the prediction of disease.
Asunto(s)
Colesterol/sangre , Colorantes Fluorescentes/química , Hierro/sangre , Nanopartículas/química , Puntos Cuánticos/química , Carbono/química , Catálisis , Colesterol/química , Colesterol Oxidasa/química , Colorimetría , Ferrocianuros/química , Humanos , Peróxido de Hidrógeno/química , Concentración de Iones de Hidrógeno , Límite de Detección , Oxidación-Reducción , TemperaturaRESUMEN
The initial portion of this article includes general comments regarding thyroid nodules, reference to 2 recent articles delineating guidelines for management of thyroid nodules, and discussion of several areas of disagreement with these articles and expansion of recommendations in areas not covered by the published guidelines. The main body of the article provides a detailed discussion of our technique for fine-needle aspiration biopsy of a thyroid nodule.
