A Novel Four-Degree-of-Freedom Upper Limb Rehabilitation Robot / 中国康复理论与实践

Objective:A novel four-degree-of-freedom upper limb rehabilitation robot was designed to overcome the shortcomings of the structure of the most of serial robots. Methods:The shoulder and elbow joint drive system and the information detection system were placed in the base. The synchronous belt drive system and the spiral bevel gear transmission system were designed to transmit power from the base to the shoulder and elbow joint of the arm. The cubic polynomial trajectory planning method based on the joint space was selected to accomplish the trajectory planning of the recovery movements of taking objects and drawing quadrilaterals, and the single-degree-of-freedom motion control experiment and multi-degree-of-freedom trajectory planning experiment were designed to verify the rationality and feasibility of the design. Results:Each joint of the rehabilitation robot reached the designed range of motion at the designed speed, and well completed the planned rehabilitation training movements. Conclusion:This robot can effectively reduce the volume and mass of the mechanical arm, overcome the influence of motor noise and radiation on patients' rehabilitation training, and assist patients to complete a variety of rehabilitation exercises.

Effect of thermal cycling on surface microstructure of different light-curing composite resins / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of thermal cycling on surface microstructure of different light-curing composite resins.</p><p><b>METHODS</b>A nanofilled composite (Z350) and 4 microhybrid composites (P60, Z250, Spectrum, and AP-X) were fabricated from lateral to center to form cubic specimens. The lateral surfaces were abrased and polished before water storage and 40 000 thermal cycles (5/55 degrees celsius;). The mean surface roughness (Ra) were measured and compared before and after thermal cycling, and the changes of microstructure were observed under scanning electron microscope (SEM).</p><p><b>RESULTS</b>Significant decreases of Ra were observed in the composites, especially in Spectrum (from 0.164±0.024 µm to 0.140±0.017 µm, P<0.001) and Z250 (from 0.169±0.035 µm to 0.144±0.033 µm, P<0.001), whose Ra approximated that of P60 (0.121±0.028 µm) with smoothly polished surface. SEM revealed scratches and shallower pits on the surface of all the 5 resins, and fissures occurred on Z350 following the thermal cycling.</p><p><b>CONCLUSION</b>Water storage and thermal cycling may produce polishing effect on composite resins and cause fissures on nanofilled composite resins.</p>

MRI features of Klippel-Trenaunay syndrome / 中华放射学杂志

Objective To observe and analyze the MRI manifestations of Klippel-Trenaunay syndrome(KTS).Methods Thirty-one cases with diagnosed KTS underwent MRI on a 1.5 T MR system. MRI,MR venography(MRV),MR angiography(MRA)and X-ray venography(XRV)were performed.The pathological changes of the limbs and their veins were observed.Results MRI found soft tissue hemangiomas in 12 cases,soft tissue swelling of the extremities in 27 cases,superficial varicosities in 21 cases,and malformation of the veins in 27 cases.In twenty patients who underwent both MRV and XRV, superficial varicosities in 17 cases and persistent sciatic veins in 11 cases were found with both techniques. The increase of tributary veins was found in 10 cases with XRV,while found in 15 cases with MRV.The erratic venous course was found in 4 cases with MRV.The abnormalities of deep veins were found in 8 cases with MRV,while found in 7 cases with XRV.Conclusion MRI is an efficient and reliable imaging method for diagnosis of KTS.