Abstract
J-PARC Main Ring (MR) delivers a slow extracted 30 GeV proton beam to the Hadron Experimental Facility using third-order resonance. One of the critical properties required for the proton ...beam is the flatness of the time structure of the extracted beam (spill structure). We performed a simple beam simulation of the MR slow beam extraction to investigate the effect of the current ripples of the main magnet power supplies on the beam spill structure. In addition, we investigated in the simulation the effects of the feedback control system on the betatron tune using fast Q magnets and the transverse RF system to improve the spill structure. The simulation qualitatively reproduced the measured spill structures. Now the attempts to optimize their parameters for better spill structure are ongoing.
Slow extraction from the J-PARC main ring using a dynamic bump Tomizawa, M.; Arakaki, Y.; Kimura, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2018, Letnik:
902
Journal Article
Recenzirano
A dynamic bump under the achromatic condition has been applied for third integer slow extraction from the Japan Proton Accelerator Research Complex main ring. This dynamic bump scheme has drastically ...reduced beam loss rate for slow extraction compared to that for a fixed bump mode. The low beam loss rate for slow extraction has been retained for high power operations. A beam power of 41−44.4 kW was achieved for physics runs using the slow extraction by applying the dynamic bump scheme. The beam profile measured just upstream of the target indicates that the beam spot at the target does not travel over the entire extraction time. This behavior is advantageous for experimental data acquisition.
Background: While tumour necrosis factor α (TNF-α) appears to be associated with the development of non-alcoholic steatohepatitis (NASH), its precise role in the pathogenesis of NASH is not well ...understood. Methods: Male mice deficient in both TNF receptors 1 (TNFR1) and 2 (TNFR2) (TNFRDKO mice) and wild-type mice were fed a methionine and choline deficient (MCD) diet or a control diet for eight weeks, maintaining isoenergetic intake. Results: MCD dietary feeding of TNFRDKO mice for eight weeks resulted in attenuated liver steatosis and fibrosis compared with control wild-type mice. In the liver, the number of activated hepatic Kupffer cells recruited was significantly decreased in TNFRDKO mice after MCD dietary feeding. In addition, hepatic induction of TNF-α, vascular cell adhesion molecule 1, and intracellular adhesion molecule 1 was significantly suppressed in TNFRDKO mice. While in control animals MCD dietary feeding dramatically increased mRNA expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) in both whole liver and hepatic stellate cells, concomitant with enhanced activation of hepatic stellate cells, both factors were significantly lower in TNFRDKO mice. In primary cultures, TNF-α administration enhanced TIMP-1 mRNA expression in activated hepatic stellate cells and suppressed apoptotic induction in activated hepatic stellate cells. Inhibition of TNF induced TIMP-1 upregulation by TIMP-1 specific siRNA reversed the apoptotic suppression seen in hepatic stellate cells. Conclusions: Enhancement of the TNF-α/TNFR mediated signalling pathway via activation of Kupffer cells in an autocrine or paracrine manner may be critically involved in the pathogenesis of liver fibrosis in this NASH animal model.
A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer resonant extraction and delivered to the hadron experimental facility. A dynamic bump scheme ...under achromatic condition drastically reduces beam hit rate on the septa devices, and we have attained 51 kW SX operation at 5.2 s cycle with high slow extraction efficiency of 99.5%. A spill duty factor indicating a uniformity of the time structure of the extracted beam is typically 50%. The current SX performance and future plans for improvements will be presented.
In the main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC), the power supplies of magnets induce large ripples in the betatron tunes. The tune ripples degrade the quality of the ...beam spill on the slowly extracted beam. To improve the spill quality, the J-PARC MR employed a feedback system using a beam spill monitor; however, the existing system could not correct the beam spills suitably, since the tune ripples were too large. We developed a new correction system using the information of magnet currents as an input of the correction. The new system consists of current monitors and a corrector quadrupole, and it allows us to correct the ripples in real time. Using this system, we successfully corrected the tune ripples for the first time in the J-PARC MR. The correction system improved the spill quality from 3% (without any correction) to 30% (with the new correction), whereas the quality using the present feedback system is 17.4%.
Retrospective investigations of odontomas in Japanese children and one recurrent case were carried out. Thirty‐nine cases of odontoma in 38 children were treated in the Paediatric Dentistry Clinic of ...Niigata University Dental Hospital between September 1979 and December 2002. The patients consisted of 23 males and 15 females and their ages ranged from 1 year 2 months to 14 years old. The chief complaints were delayed tooth eruption in 19 cases (five: primary teeth, 14: permanent teeth), retention of primary teeth in 11, incidentally found on the radiographic examination in eight cases, and swelling of the jaw in one case. Thirty‐four cases (87%) were associated with tooth eruption disturbances. The most frequently affected region was the maxillary anterior region. Treatment consisted of surgical removal of odontomas in all cases, after which if the impacted teeth did not erupt, exposure of the crown and/or orthodontic traction was performed. Pathological diagnoses were compound odontoma in 30 cases, complex odontoma (n = 7), and compound and complex odontoma (n = 2). A retrospective study of the radiographs revealed the developing process of odontomas in four cases and odontoma disturbed tooth eruption since the early uncalcified developing stage.
A recurrent case was a boy aged 6 years 5 months in whom the first surgical removal of odontoma was performed at the age of 1 year 8 months. Recurrence of an odontoma is very rare, but in very young children odontomas are in the early developing stages, containing uncalcified portions, so it is important to perform periodical observations until the succedaneous teeth erupt.
The neonicotinoids, the newest major class of insecticides, have outstanding potency and systemic action for crop protection against piercing-sucking pests, and they are highly effective for flea ...control on cats and dogs. Their common names are acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam. They generally have low toxicity to mammals (acute and chronic), birds, and fish. Biotransformations involve some activation reactions but largely detoxification mechanisms. In contrast to nicotine, epibatidine, and other ammonium or iminium nicotinoids, which are mostly protonated at physiological pH, the neonicotinoids are not protonated and have an electronegative nitro or cyano pharmacophore. Agonist recognition by the nicotinic receptor involves cation-pi interaction for nicotinoids in mammals and possibly a cationic subsite for interaction with the nitro or cyano substituent of neonicotinoids in insects. The low affinity of neonicotinoids for vertebrate relative to insect nicotinic receptors is a major factor in their favorable toxicological profile.
The HLA-Cw6 antigen has been associated with psoriasis vulgaris despite racial and ethnic differences. However, it remains unclear whether it is the HLA-Cw6 antigen itself or a closely linked, ...hitherto unidentified, locus that predisposes to the disease. Here, in order to map the susceptibility locus for psoriasis vulgaris precisely within the HLA class I region, 11 polymorphic microsatellite markers distributed throughout a 1060 kb segment surrounding the HLA-C locus were subjected to association analysis in Japanese psoriasis vulgaris patients. Statistical analyses of the distribution and deviation from Hardy-Weinberg equilibrium of the allelic frequency at each microsatellite locus revealed that the pathogenic gene for psoriasis vulgaris is located within a reduced interval of 111 kb spanning 89–200 kb telomeric of the HLA-C gene. In addition to three known genes, POU5F1, TCF19 and S, this 111 kb fragment contains four new, expressed genes identified in the course of our genomic sequencing of the entire HLA class I region. Therefore, these seven genes are the potential candidates for susceptibility to psoriasis vulgaris.
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