Marker-3D Measurement Versus Traditional Radiograph Measurement in the Treatment of Tibiofibular Fracture Using Taylor Spatial Frame

Background: The Taylor Spatial Frame (TSF) has been widely used for tibiofibular fractures. However, traditional radiograph measurement method is complicated and the reduction accuracy is not high enough for correcting residual deformities. We proposed the marker-3D measurement method to solve these problems. This study aimed to compare the reduction accuracy of the traditional radiograph measurement method and the marker-3D measurement method in tibiofibular fracture treated with TSF.Methods: From January 2016 to June 2019, A retrospective analysis was performed based on the patients with tibiofibular fracture treated with TSF in our department. 41 patients were qualified for this study, including 21 patients in the marker-3D measurement group (experimental group) and 20 patients in the traditional radiograph measurement group (control group). In the experimental group, CT scan was performed for 3D reconstruction with 6 markers installed on the TSF, to determine the adjusting plan. In the control group, the anteroposterior (AP) and lateral radiographs were performed for the deformity parameters. X-rays were taken to measure the residual deformities after correction.Results: All patients reached functional reduction. The residual displacement deformity (RDD) in AP radiograph was 0.5 (0, 1.72) mm in experimental group and 1.74 (0.43, 3.67) mm in control group. The residual angle deformity (RAD) in AP radiograph was 0 (0, 1.25) ° in experimental group and 1.25 (0.62, 1.95) °in control group. As to the Lateral radiograph, the RDD was 0 (0, 1.22) mm in experimental group and 2.02 (0, 3.74) mm in control group. The RAD was 0 (0, 0) ° in experimental group and 1.42 (0, 1.93) ° in control group. Significant differences in all above comparisons were found between the groups (AP radiograph RDD: P = 0.024, RAD: P = 0.020; Lateral radiograph RDD: P = 0.016, RAD: P = 0.004). Conclusions: Both groups achieved satisfactory fracture reduction. However, the residual deformities in the experimental group were significantly smaller. This study proved that the marker-3D measurement method could further improve the reduction accuracy.

TRACTOR DYNAMICS AS A COMPLEX MECHANICAL SYSTEM SPATIAL FRAME TYPE

Purpose of the study is to develop a matrix method for studying the dynamics of a tractor as a multi-mass spatial system of rigid bodies with an arbitrary arrangement of elastic suspension of bodies on shock absorbers relative to a fixed support surface and the presence of elastic connections between the bodies, made in the form of beam elements. Research methods. The methodological basis of the work is the generalization and analysis of well-known scientific results regarding the dynamics of two-mass systems in resonance modes and the use of a systematic approach. The analytical method and comparative analysis were used to form a scientific problem, determine the goal and formulate the research objectives. When creating empirical models, the main provisions of the theory of stability of systems, methodology of systems analysis and research of operations were used. The results of the study. A wheeled vehicle is presented as an amortized continuous frame type structure with assemblies and assembly units located on it, as well as a methodology for calculating individual block matrices of stiffness and damping coefficients. In this case, it is assumed that a viscous damper can be connected in parallel to each elastic element. In this construction of the stiffness and damping matrix of the block matrix are formed in the same way. Damping matrices are derived from the corresponding matrices by substituting damping constants instead of stiffness constants. To determine the natural frequencies and vibration modes of an undamped system using a PC, the most effective method of diagonalization by successive rotations. This method provides a complete solution to the problem, allowing all frequencies and shapes to be determined simultaneously, and good convergence. Conclusions. The considered method for analyzing and calculating the dynamics and vibration damping of a tractor as a complex mechanical system is based on a matrix record of the problem of spatial vibrations of a system of rigid bodies with elastic bonds. Matrix equations seem to be especially useful in the study of complex tightly coupled systems with the obligatory use of a PC. The presented work provides a complete methodology for calculating a tractor as a complex mechanical system such as a spatial frame with equipment installed on it.

Afropessimism, Liminal Hotspots, and Claude McKay’s Aesthetic of Sovereign Rejection in Romance in Marseille

This article considers Claude McKay’s Romance in Marseille through two emerging fields of study: “Afropessimism” and anthropological theories of the “liminal hotspot.” It suggests that McKay’s novel functions as a critique of positive Harlem Renaissance images of diasporic movement by highlighting how racial “Blackness” functions as a system for rejecting people of color from the benefits of modernity and sovereign rights-bearing status in an expanded temporal and spatial frame. To explore this hypothesis, the article turns to new anthropological work on the liminal hotspot as a site of sustained, unresolved transition, reading the affectivity of diaspora as a negative one in McKay’s work that places an unsustainable pressure on ritual and performative stylizations and renders them untenable as forms for cultivating a sovereign condition.