Construction of a new primary beam line, called the B-line, started in 2013 at the J-PARC Hadron Experimental Facility. The B-line is branched at the middle of an existing primary proton beam line ...(A-line) in the beam switching yard (SY), which is the connecting tunnel between the Main Ring (MR) and the Hadron experimental hall (HD-hall). At the branching point, about 0.1% of the primary beam is kicked off at 5 degrees using a Lanbertson magnet and two septum magnets. The Lambertson magnet has a field free hole in its yoke. The proton beam that goes through a field region is separated from the A-line, and it is extracted to the B-line. The rest of the beam that goes through the field free hole is transported through the existing primary beam line. Since a significant beam loss as much as 420 W occurs at the edge of field free hole, the magnets near the Lambertson magnet are operated under a very high radioactive environment. We have developed a "mini-chimney system" regarding easy maintenance of those magnets. The mini-chimney means a vertical tower of approximately 1m in height. The tower is comprised of water pipes, power electrodes, and signal cables for safety interlock. Those can be easily connected and disconnected at the top of chimney on the ceiling iron shields. In this paper we summarize the maintenance scheme developed for the B-line, as well as the design of B-line.In May 2020, the first proton beam was successfully extracted to the B-line by means of the Lambertson and the septum magnets. Up to now, the 10 10 protons per 5.2 sec accelerator cycle shot have been available.
Abstract Cell therapy using stem cells is awaited by stroke patients with impaired movement and cognitive functions, although intravenous alteplase-administration ameliorated outcomes of patients ...receiving the therapy within 3 h of onset. In this study, we explored the therapeutic effects of neural progenitor cells (NPC) upon middle cerebral artery occlusion (MCAO) model of rats with exploration of the differences between adult and embryonic NPCs in therapeutic effects. GFP-labeled adult or embryonic NPCs were transplanted for transient MCAO model of rats at 1h after reperfusion. Rats were examined behaviorally using limb placement test, rotarod test and cylinder test with neuroradiological assessment using magnetic resonance imaging (MRI). Consequently after euthanasia, rats were immunohistochemically investigated to explore graft survival and immune reaction. MRI of rats receiving NPCs revealed significant reduction of infarct volumes, compared to vehicle-treated rats with corresponding behavioral amelioration. The transplanted cells were surviving in rats receiving NPCs, although the number of embryonic NPCs was significantly higher than that of adult NPCs. Iba-1-positive inflammatory cells of rats receiving adult NPCs were prominent, compared to those receiving embryonic NPCs, which might be a rationale for the differences between rats receiving adult and embryonic NPCs in the number of surviving NPCs. On the contraries, adult NPCs surely demonstrated therapeutic effects with a few surviving cells, thus indicating that the therapeutic effects might be due to trophic/growth factor-secretion from transplanted NPCs, rather than replacement of damaged host neurons. Therapeutic effects of NPCs for MCAO model of rats were clarified in this study. Transplantation of NPCs will be a hopeful strategy for stroke patients, although further studies are required for the patient safety and underlying mechanisms.
Cell transplantation has been shown to be an effective therapy for central nervous system disorders in animal models. Improving the efficacy of cell transplantation depends critically on improving ...grafted cell survival. We investigated whether glial cell line-derived neurotrophic factor (GDNF)-pretreatment of neural stem cells (NSCs) enhanced grafted cell survival in a rat model of Parkinson's disease (PD). We first examined the neuroprotective effects of GDNF on oxygen-glucose deprivation (OGD) in NSCs. Cells were pretreated with GDNF for 3 days before subjecting them to OGD. After 12h of OGD, GDNF-pretreated NSCs showed significant increases in survival rates compared with PBS-pretreated NSCs. An apoptosis assay showed that the number of apoptotic cells was significantly decreased in GDNF-pretreated NSCs at 1h and 6h after OGD. A PD rat model was then established by unilateral injection of 6-hydroxydopamine (6-OHDA, 9μg) into the medial forebrain bundle. Two weeks after 6-OHDA injection, GDNF-pretreated NSCs, PBS-pretreated NSCs, or PBS were injected into PD rat striatum. The survival of grafted cells in the striatum was significantly increased in the GDNF-pretreated NSC group compared with the control groups. GDNF pretreatment increased survival of NSCs following transplantation, at least partly through suppression of cell apoptosis.
Silicon carbide (SiC)-particle-dispersed-aluminum (Al) matrix composites were fabricated in a unique fabrication method, where the powder mixture of SiC, pure Al and Al–5mass% Si alloy was uniquely ...designed to form continuous solid–liquid co-existent state during spark plasma sintering (SPS) process. Composites fabricated in such a way can be well consolidated by heating during SPS processing in a temperature range between 798K and 876K for a heating duration of 1.56ks. Microstructures of the composites thus fabricated were examined by scanning electron microscopy and no reaction was detected at the interface between the SiC particle and the Al matrix. The relative packing density of the Al–matrix composite containing SiC was higher than 99% in a volume fraction range of SiC between 40% and 55%. Thermal conductivity of the composite increased with increasing the SiC content in the composite at a SiC fraction range between 40vol.% and 50vol.%. The highest thermal conductivity was obtained for Al–50vol.% SiC composite and reached 252W/mK. The coefficient of thermal expansion of the composites falls in the upper line of Kerner’s model, indicating strong bonding between the SiC particle and the Al matrix in the composite.
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