20 research outputs found

    Spontaneous Formation of Spherical Tokamak by ECH on LATE

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    Spontaneous formation of spherical tokamak is observed during a microwave discharge at the electron cyclotron resonance (ECR) under a steady vertical magnetic field. In the course of slow plasma current increase, a fast rise of current (usually within several ms) occurs and the magnetic field topology changes drastically from open field type to closed one. After this current jump, a steady plasma current is maintained. The plasma current in the steady stage is proportional to the strength of the vertical field which balances the outward hoop force of the plasma current and maintains the MHD equilibrium. When a 5GHz, 130kW, 60ms microwave power is injected at 85G vertical field, plasma current of 6.8kA is obtained

    A Novel Non-Gas Endospray for Applying Fibrin Glue in Laparoscopic Surgery

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    Purpose: Fibrin glue and polyglycolic acid felt are used for tissue repair in various surgical procedures. However, using a spray device to apply fibrin sealant during laparoscopic surgery can increase the intraperitoneal pressure, which can cause complications such as air embolism. We developed a novel non-gas endospray for use in laparoscopic surgery. This study aimed to evaluate the sealing effect of this non-gas endospray in comparison with a conventional gas-spray device and to evaluate the safety of its application in the clinical setting. Materials and Methods: An ex vivo pressure test model was used to assess the sealing effect of the non-gas endospray (method 1) versus conventional gas-spray (method 2). A bottle was sealed with a rabbit skin sample that had been pierced nine times by a 19G needle. Each skin sample was sealed using either method 1 or method 2 (n = 10 for each method). The non-gas endospray was then used in two patients undergoing laparoscopic splenectomy with CO2 pneumoperitoneum. Intra-abdominal pressure was measured throughout the surgery. Results: Bursting pressures were similar in method 1 (246.9 ± 123.2 mmHg) and method 2 (265.5 ± 93.6 mmHg; P = 0.7082). During laparoscopic splenectomy, the non-gas endospray was successfully used to apply fibrin glue without any increase in intra-abdominal pressure. Conclusions: The novel non-gas endospray produced a strong sealing effect similar to that of a conventional gas-spray device and has thus far proved feasible in the clinical setting

    The role of growth differentiation factor 15 in the pathogenesis of primary myelofibrosis

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    Growth differentiation factor 15 (GDF15) is a pleiotropic cytokine that belongs to the transforming growth factor-β superfamily. Elevated serum concentrations of this cytokine have been reported in patients with various malignancies. To assess the potential roles of GDF15 in hematologic malignancies, we measured its serum levels in patients with these diseases. We found that serum GDF15 levels were elevated in almost all these patients, particularly in patients with primary myelofibrosis (PMF). Immunohistochemical staining of bone marrow (BM) specimens revealed that GDF15 was strongly expressed by megakaryocytes, which may be sources of increased serum GDF15 in PMF patients. Therefore, we further assessed the contribution of GDF15 to the pathogenesis of PMF. Recombinant human (rh) GDF15 enhanced the growth of human BM mesenchymal stromal cells (BM-MSCs), and it enhanced the potential of these cells to support human hematopoietic progenitor cell growth in a co-culture system. rhGDF15 enhanced the growth of human primary fibroblasts, but it did not affect their expression of profibrotic genes. rhGDF15 induced osteoblastic differentiation of BM-MSCs in vitro, and pretreatment of BM-MSCs with rGDF15 enhanced the induction of bone formation in a xenograft mouse model. These results suggest that serum levels of GDF15 in PMF are elevated, that megakaryocytes are sources of this cytokine in BM, and that GDF15 may modulate the pathogenesis of PMF by enhancing proliferation and promoting osteogenic differentiation of BM-MSCs
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