Stable long-term operation of superconducting current-feeder system for the LHD

A superconducting (SC) current-feeder system is used as the current transmission lines for the experimental fusion device, LRD. It consists of nine flexible SC bus lines with total length of 497 m, and nine pairs of gas-cooled current leads. To avoid the propagation of the ice on the leads, the temperature of the terminals had been kept in the range between 5 and 20 degrees C by the heaters. The measured voltage drops of all leads were less than 20 mV. The liquid helium levels of the leads and the sub-cooler tank will equalize by the siphon method. The total time of the coil excitations exceeds 3000 hours. We have demonstrated successfully that the SC current-feeder system was stable and easy to handle, and is useful for the SC experimental fusion device

A Case of Holocord Leptomeningeal Dissemination from Cerebellar Hemangioblastoma without von Hippel-Lindau Disease

Hemangioblastoma disseminated along leptomeninges from the solitary cranial lesion without von Hippel-Lindau (VHL) disease is a quite rare instance with 23 cases reported in 40 years. We add a new case and discuss these rare instances. A 55-year-old female underwent surgery for total removal of cerebellar hemangioblastoma. Twenty months later, magnetic resonance (MR) images of the spinal cord revealed a tumor compressing the thoracic cord at T3-4 level which was removed en bloc by emergent spinal surgery. However, paraplegia and bowel bladder dysfunction recurred 5 months after the spinal surgery. Spine MR images showed diffuse enhancement of subarachnoid space. Exploratory surgery disclosed that the enhanced lesion was disseminated hemangioblastoma. After whole spinal irradiation, she was transferred to a palliative care hospital. Even after complete removal, possibility of leptomeningeal dissemination demands continuous follow-up. The mechanism of seeding of hemangioblastoma remains unclear, but attention must be paid to avoid spreading tumor cells during surgery because all the disseminated cases had precedent cranial surgery

First Cool-Down Performance of the LHD

The first cool-down test of the Large Helical Device (LHD) and the performance of the LHD cryogenic system during the first cycle operation are described. The first cool-down started on Feb. 23, 1998 and finished on Mar. 22. After the cool-down, the excitation tests of the SC coils up to 1.5 T and the first cycle operations for plasma physics experiments were conducted until May 18. The first cycle operation was successfully completed after the warm-up process to room temperature from May 19 to Jun. 15. The cooling characteristics of the LHD, such as temperature distribution during cool-down, heat loads under steady state condition, reliability during long-term operation, are reporte

Conductor and joint test results of JT-60SA CS and EF coils using the NIFS test facility

In 2007, JAEA and NIFS launched the test project to evaluate the performance of cable-in-conduit (CIC) conductors and conductor joints for the JT-60SA CS and EF coils. In this project, conductor tests for four types of coil conductor and joint tests for seven types of conductor joint have been conducted for the past eight years using the NIFS test facility. As a result, the test project indicated that the CIC conductors and conductor joints fulfill the design requirement for the CS and EF coils. In addition, the NIFS test facility is expected to be utilized as the test facility for the development of a conductor and conductor joint for the purpose of the DEMO nuclear fusion power plant, provided that the required magnetic field strength is within 9 T

Reconstruction of Pterional Key Hole Using Three-dimensional Titanium Plate : Technical Note

Patients who have undergone pterional craniotomy sometimes complain about postoperative cosmetic impairment in the frontotemporal area. This problem occurs as a result of inappropriate repair or no repair of the pterional key hole. The authors have developed an intraoperative hand-made three-dimensional titanium plate, and as a result of using this plate the postoperative cosmetic appearance was satisfactory

A Case of Venous Angioma with Arteriovenous Shunts : Case Report

A 35-year-old man presented with a sudden headache and disturbance of consciousness. On admission, his consciousness level was Japan Coma Scale 100. Computed tomography disclosed a subarachnoid hemorrhage (SAH) and right cerebellar hematoma. Angiography was performed and, at first, arteriovenous malformation of the posterior fossa was diagnosed. Then external decompression of the posterior fossa and ventricular drainage were performed, followed by barbiturate therapy. Repeat angiography revealed that the lesion was a venous angioma with arteriovenous shunts. On day 37, subtotal removal of the lesion was performed. Intraoperatively, acute brain swelling emerged and partial internal decompression of the right cerebellar hemisphere was performed. The postoperative course was comparatively good and the patient was discharged with very mild ataxia. The patient is now being followed up in our outpatient clinic

Morphological Pattern and Classification of the Superficial Middle Cerebral Vein by Cadaver Dissections: An Embryological Viewpoint

In this study, we used 45 adult cadaveric cerebral hemispheres to investigate the anatomical classification of the superficial middle cerebral vein (SMCV) based on the number of stems, course, and anastomosis at the distal portion. We classified the SMCVs into five types based on embryological concept. Type A (18 cases, 40.0%) is that the frontosylvian veins (FSVs) merge with the vein of Trolard (VT) and the vein of Labbé (VL) at the distal portion of the sylvian fissure. Type B (5 cases, 11.1%) is that the temporosylvian veins (TSVs) merge with the VT and the VL at the distal portion. Type C (13 cases, 28.9%) is that no vein merge with the VT and the VL at the distal portion. The VT merges with the SMCV from the FSV and the VL merges with the SMCV from the TSV. They course along the sylvian fissure and merge at the proximal portion. In Type D (eight cases: 17.8%), the VT and the VL merge at the distal portion, and the SMCV from the FSV and the SMCV from the TSV join their confluence without merging. Type E (one case, 2.2%) show an undeveloped SMCV. Formation rate of intravenous anastomoses or bridging veins(BVs) at the distal portion between the frontosylvian trunk (FST) and the temporosylvian trunk (TST), between the FST and the temporal lobe, and between the TST and the frontal lobe was very low, because these formation may be difficult to occur during the embryological process in which the SMCV is formed from the telencephalic vein

A Japanese Pedigree of Familial Cerebral Cavernous Malformations : A Case Report

Familial cerebral cavernous malformations (FCCM) are autosomal-dominant vascular malformations. At present, 3 cerebral cavernous malformation genes (KRIT1/CCM1, MGC4607/ CCM2, and PDCD10/CCM3) have been identified. Few genetic analyses of Japanese FCCM have been reported. A Japanese pedigree of 4 patients with FCCM has been reported that includes the genetic analysis of one of the patients. All 4 patients showed multiple lesions in the brain. Surgical removal was performed at our hospital due to enlargement or hemorrhage of the intracranial lesions in a 21-year-old female (Case 1) and a 30-year-old male (Case 2). The histological diagnoses were cavernous malformations. A 62-year-old female (Case 4), the mother of Cases 1, 2, and 3, suffered from intramedullary hemorrhage at T6-7 and surgical removal was performed at another hospital. Only one patient, a 32-year-old female (Case 3), did not show symptoms. The genetic analysis of Case 2 demonstrated heterozygous partial deletions of exons 12-15 of the KRIT1 gene