ABSTRACT
Graphene has been investigated as a transparent conductive film for use in a variety of devices, and in recent years it has shown promise for use in millimeter-wave devices as 5G technology. In this study, we applied single-layer (SL), triple-layer (3L), and P-type doped 3L graphene to coplanar waveguide (CPW) transmission lines and obtained transmission characteristics (S21) from 1 to 50 GHz, which covered the 5G band. Furthermore, an equivalent circuit model of the CPW used in the measurements was constructed and simulations were performed, which showed good agreement with the measured results. The results validated the transmission properties of the graphene and the contact impedance at the interface between electrodes and the graphene in CPW circuits, which are necessary parameters for designing antennas using graphene. In addition, by comparing the transmission loss of three types of graphene, the parameters for improving the transmission characteristics were clarified.
ABSTRACT
Osteochondral fractures of the fingers are challenging to treat, and it is mandatory to acquire early bone union and joint surface reconstruction to obtain satisfactory outcomes. These injuries sometimes occur as open fractures with poor soft tissue condition and bone defect adjacent to osteochondral fragment. For such cases, surgical treatment can be more difficult, and vascularized bone graft (VBG) could be a useful method for joint reconstruction. Here, we report reverse-pedicled VBG based on the radiodorsal artery of the thumb for reconstructing a traumatic bone defect of the thumb. A 36-year-old man, who had ulcerative colitis and was taking immunosuppressive agents, sustained open fracture-dislocation of the thumb interphalangeal joint with a free osteochondral fragment of the proximal phalanx and 6 × 5 × 4 mm of subcondylar bone defect. We harvested 5 × 5 × 5 mm VBG at the base of the first metacarpal bone and dissected running the radiodorsal artery. The vascularized bone was grafted into the bone defect site through the subcutaneous tunnel created on the radial aspect of the proximal phalanx and fixed with a Kirschner wire. Bony union was obtained 2 months after surgery. At 7 months after the operation, the patient complained no pain, and the range of motion of the thumb interphalangeal joint was extension 0° and flexion 42°. Radiographs showed no avascular necrosis of the united fragment and osteoarthritis of the interphalangeal joint. This method could be a useful option for reconstruction of the thumb with bone defects.