Dynamic External Fixator Combined with Volar Locking Plate Fixation for the Treatment of AO Type C3 Distal Radius Fractures

Background: AO type C3 distal radius fracture (DRF) is the most difficult-to-treat fracture type because of a tendency to shorten and collapse. The purpose of this study is to investigate the clinical and radiographic outcomes of comminuted intra-articular DRFs treated with a dynamic external fixator combined with a volar locking plate (VLP). Methods: Eleven patients (mean age, 61 years) with comminuted intra-articular DRFs were treated with a dynamic type of external fixator combined with a VLP. Following reduction and fixation with a VLP, the dynamic external fixator was applied and the distal ball joint of the fixator was aligned with the lunate-capitate line. The ball joint was unlocked approximately 2 weeks after surgery to allow wrist mobilization. The fixator was removed 3 - 6 weeks (mean, 5 weeks) after surgery. Consequently, clinical and radiographic assessments were carried out at the final follow-up. Results: At the final follow-up, the mean range values of wrist extension and flexion were 76°and 64°, respectively. Compared with the contralateral side, the mean grip strength was 84%. The mean Modified Mayo Wrist Score and the Disabilities of the Arm, Shoulder and Hand score were 88 and 9, respectively. No significant differences in the radiographic parameters exist between after surgery and final follow-up. Conclusions: This study indicated that the dynamic wrist fixator combined with a VLP is effective for the treatment of AO type C3 DRFs.

Dynamic external fixator combined with limited internal fixation for Pilon reactures

Objective To evaluate effects of manipulative reduction,dynamic external fixator combined with limited internal fixation for the treatment of Pilon fractures.Methods From January 2007 to June 2009,manipulative reduction,dynamic external

Comprehensive urbanization level and its dynamic factors for five Central Asian countries

In the context of accelerated development of the Silk Road Economic Belt,it is necessary to conduct in-depth research on urbanization of Central Asian countries.This paper analyzes the spatial and temporal patterns and evolution dynamics of urbanization during the period 1991-2017 from the perspective of internal-external forces.The results are as follows.(1)The urbanization process of the five Central Asian countries studied is significantly influenced by their political and economic situations and displays periodic characteristics.All five countries experienced a stagnation development stage at the beginning of independence,and then a rapid growth stage since the year 2000.The average annual growth rates of the two stages were 0.19% and 1.45%,respectively.(2)Differences in the urbanization of the studied countries are obvious,and the evolutionary characteristics of each subsystem of urbanization are different.It is therefore necessary to distinguish and clearly understand the urbanization process of each country.(3)Internal and external factors play a role in the urbanization processes of Central Asian countries.External railway transportation facilities are particularly important for the development of urbanization in these countries.The regression coefficients of railway construction length,total merchandise trade and actually utilized foreign capital are 0.5665,0.0937 and 0.0806,respectively.(4)Countries with smaller populations and economic scales need to engage in international cooperation to promote healthy development of urbanization.The results of the study indicate that internal and external factors work together in the urbanization process of Central Asian countries,and external forces are particularly important for the development of such urbanization.

Computational fluid dynamics simulation of hydrodynamics in the riser of an external loop airlift reactor

Local hydrodynamics in the riser of an external loop airlift reactor （EL-ALR） are identified and the performances of three drag models are evaluated in computational fluid dynamics simulation. The simulation results show that the Schiller-Naumann drag model underestimated the local gas holdup at lower superficial gas velocity whereas the Tomiyama drag model overestimated that at higher superficial gas velocity. By contrast, the dual-bubble-size （DBS）-local drag model gave more reasonable radial and axial distri-butions of gas holdup in all cases. The reason is that the DBS-local drag model gave correct values of the lumped parameter, i,e., the ratio of the drag coefficient to bubble diameter, for varying operating conditions and radial positions. This ratio is reasonably expected to decrease with increasing superficial gas velocity and be smaller in the center and larger near the wall. Only the DBS-local drag model correctly reproduced these trends. The radial profiles of the axial velocity of the liquid and gas predicted by the DBS-local model also agreed well with experimental data.