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Modification of JT-60 as a full superconducting tokamak (JT-60SC) is planned. The objectives of the JT-60SC programme are to establish scientific and technological bases for steady-state operation of high performance plasmas and utilization of reduced-activation materials in an economically and environmentally attractive DEMO reactor. Advanced fusion technologies relevant to the DEMO reactor have been developed for the superconducting magnet technology and plasma facing components of the JT-60SC design. To achieve a high current density in a superconducting strand, Nb₃Al strands with a high copper ratio of 4 have been newly developed for the toroidal field coils (TFCs) of JT-60SC. The R&D to demonstrate the applicability of the Nb₃Al conductor to TFCs by a react-and-wind technique has been carried out using a full-size Nb₃Al conductor. A full-size NbTi conductor with low ac loss using Ni-coated strands has been successfully developed. A forced cooling divertor component with high heat transfer using screw tubes has been developed for the first time. The heat removal performance of the carbon fibre composite target was successfully demonstrated on an electron beam irradiation stand.

AbstractA modification of the JT-60 is planned to be a superconducting tokamak (JT-60SC) in order to establish steady-state operation of high beta plasma for 100 s, and to ensure the applicability of ferritic steel as a reduced activation material for reactor relevant break-even class plasmas. This paper describes the detailed design of the vacuum vessel, which has a unique structure for cost effective manufacturing, as well as structural analysis results for a feasibility study.

Designs and operations of the gas system and pellet injection systems for JT-60 and JT-60U are described. A gas injection valve that is a key component of the gas injection system was developed using a multilayer piezoelectric element. The maximum flow rate of this system is 43.3 Pa⋅m3/s. The valve has mechanism for adjustment at atmospheric side meaning that a repair and an adjustment can be conducted without ventilation inside a vacuum vessel. It was confirmed that the effect of magnetic field and temperature change on the valves in the JT-60U environment was negligible.In JT-60U, two systems of pellet injector – a pneumatic drive and a centrifugal one – were developed. The pneumatic type attained a pellet velocity of 2.3 km/s, which was the world record at the time in 1988. On the other hand, the centrifugal one was developed in 1998. This injector can eject trains of up to 40 cubic (2.1 mm3) pellets at frequencies of 1 to 10 Hz and speed of 0.1 to 1.0 km/s. A guide tube for a magnetic high field side injection (HFS) (top) was also developed in 1999. The pellet injection experiment with the HFS system started in 2000. In addition, another guide tube for HFS(mid) injection was newly developed and installed in March 2001. These systems are working well.

The design of the JT-60U tokamak, the configuration of the coil power supplies, and the operational experiences gained to date are reviewed. JT-60U is a large tokamak upgraded from the original JT-60 in order to obtain high plasma current, large plasma volume, and highly elongated divertor configurations. All components inside the toroidal magnetic field coils, such as vacuum vessel, poloidal magnetic field coils, divertor, etc., were modified. Various technologies and ideas were introduced to develop these components; for example, a multi-arc double skin wall structure for the vacuum vessel and a functional poloidal magnetic field coil system with taps for obtaining various plasma configurations. Furthermore, boron-carbide coated carbon fiber composite (CFC) tiles were used as divertor tiles to reduce erosion of carbon-base tiles. Later, a semiclosed divertor with pumps, for which cryo-panels originally used for NBI units were converted, was installed in the replacement of the open divertor. These development and operational results provide data for future tokamaks. Major failures experienced in the long operational period of JT-60U, such as water leakage from the toroidal magnetic field coil, fracture of carbon tiles, and breakdown of a filter capacitor, are described. As a maintenance issue for tokamaks using deuterium fueling gas, a method for reducing radiation exposure of in-vessel workers is described.

Objectives: we determined the incidence and specific markers of postoperative delirium in elderly patients with chronic lower limb ischaemia. Patients and methods: since April, 1995, 110 patients aged 60 years or older (mean: 71.6±6.6 years) who underwent bypass surgery were assessed regarding aetiological factors of delirium: age, sex, dementia, body-mass index, hypertension, diabetes, cerebral disease, laboratory test results, severity of limb ischaemia, type of arterial occlusion, operative time, and blood transfusion. Results: discriminant analysis showed statistical significance in the following five variables: age ≥70 years; critical limb ischaemia (and/or ankle pressure <40 mmHg); dementia; duration of operation ≥7 hours; low serum albumin. The overall percentage of cases correctly classified was 78.2% (Wilks» Lambda=0.695, p<0.001); the standardized regression coefficients of the five variables were 0.648, 0.500, 0.329, 0.218, and 0.200, respectively. In logistic regression, the regression coefficients for old age and critical limb ischaemia were 2.646 (14.1 of odds ratio; 95% confidence interval, 2.7–72.0) and 1.337 (3.8; 1.3–10.9), respectively. Conclusions: the incidence of postoperative delirium in elderly patients with chronic lower-limb ischaemia was as high as 42.3%, and an age of over 70 years and critical limb ischaemia were identified as specific markers, with 14.1 times and 3.8 times the odds of suffering from delirium after bypass surgery.

A case of neuro-Behcet's syndrome is presented with sequential positron emission tomography (PET) studies. Regional cerebral blood flow (rCBF) and oxygen consumption (rCMRO2) were decreased in the brain lesion; however, on follow-up studies 3 months after steroid therapy rCBF and rCMRO2 had increased in the lesion, which demonstrated the reversibility of this disease. Such monitored improvement may accurately reflect the early stage of the disease and its response to steroid therapy.

Objectives:: To clarify the course of re-endothelialisation (Re-E) in an entire graft and to establish the effect of immersion media for the preservation of endothelial cells. Methods:: Autogenous femoral veins of dogs were immersed in heparinised saline solution (n = 18) or heparinized autogenous blood (n = 18). After immersion, the grafts were implanted into bilateral femoral artery, and were retrieved 1 day to 4-8 weeks after implantation. Results:: For the grafts immersed in the heparinised saline solution, the values for %area of endothelial cell coverage before implantation, and at 1 day, 1 week, and 4 weeks after implantation were 44.9%, 6.2%, 14.5%, and 81.3%, respectively. For the grafts immersed in heparinised autogenous blood, the values were 73.5%, 20.6%, 79.2% and 95.5%, respectively. However, such relatively rapid speed of Re-E slowed down considerably after 1 week following implantation in this group. Conclusions:: The use of heparinized autogenous blood is strongly recommended as a preparation media for autogenous vein grafts. Almost all of the endothelial cells fall away in the earlier period after implantation and regenerate multifocally and irregularly. Re-E is incomplete even at 8 weeks after surgery, and we suggest that the area of incomplete Re-E may develop into intimal hyperplasia.

Objectives:: To determine the significance of prostaglandin I^2 (PGI^2) production by medial smooth muscle cells (SMCs), we assessed PGI^2 production from denuded vein grafts and their antithrombogenicity. Materials and Methods:: A total of 30 dogs were divided into two groups: in group I, 14 dogs (27 veins, 188 segments) were used to assay PGI^2 production, which was measured as 6-keto-PGF^1^@a. In group II, 16 dogs were used for an implantation study and the thrombus-free surface (TFS) score was calculated 24h after implantation. Both groups contained the following subgroups: subgroup A, freshly harvested veins; subgroup B, endothelial denuded veins; subgroup C, veins frozen and cryopreserved; subgroup D, veins treated with protease. Results:: Values of 6-keto-PGF^1^@a (pg/mg/min) for basal and stimulated states in subgroup I-A through I-D were 58.0+/-8.9 and 530.6+/-74.7, 26.3+/-4.7 and 82.3+/-11.4, 17.9+/-1.3 and 39.4+/-3.3, and 13.3+/-1.8 and 32.2+/-6.2, respectively. The PGI^2 production in subgroup I-A were significantly higher than those in the other three subgroups (p<0.01 for basal and stimulated), while the production in subgroup I-B was also significantly higher than those in the remaining two (p<0.05 for basal and stimulated). The TFS scores in subgroup II-A through II-D were 98+/-2%, 90+/-2%, 38+/-5%, and 15+/-7%, respectively, showing significantly superior antithrombogenicity in subgroup II-B, as well as in II-A, when compared with the remaining two (p = 0.014). Conclusion:: The amount of PGI^2 generated by the medial SMCs may be sufficient for maintaining the antithrombogenicity of the endothelial denuded AVGs.

Objectives:: The role of bypass to the distal arteries for patients with Buerger's disease (thromboangiitis or TAO) remains controversial because of the high incidence of graft failure. We retrospectively reviewed the results of 71 bypasses to evaluate their efficacy. Materials and methods:: We performed 71 autogenous vein bypasses in 61 patients with TAO. Of the patients, 97% were heavy smokers. The indications for surgery were claudication in 41%, and ischaemic ulcer or gangrene in 59%. Of the bypasses 85% were to the crural arteries or to the arteries below the ankle. The grafts used were 53 single saphenous veins, and 18 venovenous composite grafts. Results:: There were 38 graft failures, the main causes including anastomosis to a diseased artery, disease progression (which occurred in smokers after surgery), and vein graft stenosis. Of 38, 10 were restored to patency by revision surgery. Primary and secondary patency rates were 48.8% and 62.5% at 5 years, and 43.0% and 56.3% at 10 years, respectively. The patency rates of the postoperative non-smoking group was significantly higher than that of the smoking group (66.8% vs. 34.7%, p < 0.05). Thirty-six patients (59%) had successful revascularisation and returned to full-time work. However, of 28 with secondary failure, 11 underwent amputation, while 14 had persistent disabling claudication. Conclusion:: Bypass to the distal arteries is an effective treatment for TAO patients, and the long-term patency is quite satisfactory as long as patients stop smoking.

A case of radiation-induced vasculopathy of a pineal glioma was presented with haemodynamic and metabolic changes before and after radiotherapy. After radiation of 60 Gy with conventional fractionation (1.8–2.0 Gy daily, 5 days per week), regional blood flow, oxygen extraction fraction, metabolic rate of oxygen, kinetic metabolic rate of glucose and the rate constants (K2, K3) were markedly depressed (20% or greater) compared with the pre-irradiated study. 7 months after radiotherapy, the patient developed transient episodes of both right and left upper limb convulsion, terminating in generalized convulsion. When she developed status epilepticus, computed tomography showed extensive low density areas in the territory supplied by the right middle cerebral and the right posterior cerebral arteries. Cerebral angiography revealed diffuse stenosis at both carotid bifurcations and at the origins of the right posterior communicating and posterior cerebral arteries. Haemodynamic and metabolic depression therefore implicated radiation-induced vasculopathy in the present case.

An intramedullary spinal cord ependymoma was studied by positron emission tomography (PET) using (11C-methyl)-L-methionine (11C-Met). MRI showed a homogeneously enhancing tumour at C6-T2 with cysts at its rostral and caudal ends. Sagittal PET images demonstrated high11C-Met uptake in the solid portion of the tumour, particularly ventrally at C7-T2, where viable tumour cells proliferated in association with abundant perforating vessels. Met-PET would appear useful for delineating the viable protion of intramedullary ependymomas.

Two cases of histologically proven primary cerebral malignant lymphoma were examined serially with positron emission tomography (PET) using11C-methyl-l-methionine (11C Met). Lesions delineated by11C Met accumulation extended beyond enhancing areas on either X-ray computed tomography (CT) or magnetic resonance imaging. High uptake of11C Met accurately showed biologically active and residual tumours, at a time when disappearance of a contrast-enhancing lesion on CT seemed to indicate involution. PET provides valuable information on the extent of tumour and assessment of radiotherapy in malignant lymphoma.

A method using piezoelectric ceramics was newly devised which permitted measurements of intramyocardial pressure. In open-chest dogs, a directional non-uniformity of the intramyocardial pressure was observed, which may be attributable to the variation in the myocardial fibre orientation.

Colloid osmotic pressure (COP) of blood from the great cardiac vein was continuously measured by the use of a membrane colloid osmometer during reactive hyperemia resulting from temporary occlusion of the anterior descending branch of left coronary artery. The COP increased sharply but transiently after the release, then it decreased below the initial level and gradually recovered. It was concluded that a measurable amount of water moved from the capillary blood into the myocardial tissue and then flowed back slowly into the capillary blood.