134 research outputs found
Transport Simulasion in a Burning Tokamak Plasma
A one-dimensional tokamak transport code (TASK/TR) has been developed to analyze the evolution of a burning plasma accompanied with fusion reaction. This code deals with the electrons, deuterons, tritons, thermalized α particles, fast α particles and beam ions, separately, in order to describe the dependence of the reaction rate on the ion mixture ratio. As an energy transport model, the drift wave turbulence mode is employed. The heating and current drive by the neutral beam injection as well as the pellet injection for fuelling are also included. This code is applied to a reactor-grade plasma aimed at in the ITER project. The cases of an ignited plasma and a current-driven plasma are examined. The required power for full current drive is estimated. The effect of pellet injection, both fuel and impurity ions, is also studied
High Pressure Steam Gasification of Coal
A high pressure reactor for the steam gasification of coal was constructed and tested for two Japanese coals. The gasification rate was determined as a function of temperature, steam pressure, partial pressure of hydrogen added to steam, and steam feed rate. The reactivity increased with steam pressure. Nickel salt was impregnated on coal to investigate its catalytic activity. The degree of the advantage by catalyst utilization decreased with increasing steam pressure. The size of residual char for Shin-Yubari coal was interpreted by the unreacted core model
Somatostatin induces hyperpolarization in pancreatic islet α cells by activating a G protein-gated K+ channel
AbstractSomatostatin inhibits glucagon-secretion from pancreatic α cells but its underlying mechanism is unknown. In mouse α cells, we found that somatostatin induced prominent hyperpolarization by activating a K+ channel, which was unaffected by tolbutamide but prevented by pre-treating the cells with pertussis toxin. The K+ channel was activated by intracellular GTP (with somatostatin), GTPγS or Gβγ subunits. It was thus identified as a G protein-gated K+ (KG) channel. RT-PCR and immunohistochemical analyses suggested the KG channel to be composed of Kir3.2c and Kir3.4. This study identified a novel ionic mechanism involved in somatostatin-inhibition of glucagon-secretion from pancreatic α cells
Geological records of transient fluid drainage into the shallow mantle wedge
Pore fluid pressure on subduction zone megathrusts is lowered by fluid drainage into the overlying plate, affecting subduction zone seismicity. However, the spatial and temporal scales of fluid flow through suprasubduction zones are poorly understood. We constrain the duration and velocity of fluid flow through a shallow mantle wedge based on the analyses of vein networks consisting of high-temperature serpentine in hydrated ultramafic rocks from the Oman ophiolite. On the basis of a diffusion model and the time-integrated fluid flux, we show that the channelized fluid flow was short-lived (2.1 × 10−1 to 1.1 × 101 years) and had a high fluid velocity (2.7 × 10−3 to 4.9 × 10−2 meters second−1), which is close to the propagation velocities of seismic events in present-day subduction zones. Our results suggest that the drainage of fluid into the overlying plate occurs as episodic pulses, which may influence the recurrence of megathrust earthquakes
Experimental model for the irradiation-mediated abscopal effect and factors influencing this effect
Radiotherapy (RT) is the primary treatment for cancer. Ionizing radiation from RT induces tumor damage at the irradiated site, and, although clinically infrequent, may cause regression of tumors distant from the irradiated site-a phenomenon known as the abscopal effect. Recently, the abscopal effect has been related to prolongation of overall survival time in cancer patients, though the factors that influence the abscopal effect are not well understood. The aim of this study is to clarify the factors influencing on abscopal effect. Here, we established a mouse model in which we induced the abscopal effect. We injected MC38 (mouse colon adenocarcinoma) cells subcutaneously into C57BL/6 mice at two sites. Only one tumor was irradiated and the sizes of both tumors were measured over time. The non-irradiated-site tumor showed regression, demonstrating the abscopal effect. This effect was enhanced by an increase in the irradiated-tumor volume and by administration of anti-PD1 antibody. When the abscopal effect was induced by a combination of RT and anti-PD1 antibody, it was also influenced by radiation dose and irradiated-tumor volume. These phenomena were also verified in other cell line, B16F10 cells (mouse melanoma cells). These findings provide further evidence of the mechanism for, and factors that influence, the abscopal effect in RT
Visceral fat obesity is the key risk factor for the development of reflux erosive esophagitis in 40–69-years subjects
[Background] Visceral fat obesity can be defined quantitatively by abdominal computed tomography, however, the usefulness of measuring visceral fat area to assess the etiology of gastrointestinal reflux disease has not been fully elucidated. [Methods] A total of 433 healthy subjects aged 40–69 years (234 men, 199 women) were included in the study. The relationship between obesity-related factors (total fat area, visceral fat area, subcutaneous fat area, waist circumference, and body mass index) and the incidence of reflux erosive esophagitis was investigated. Lifestyle factors and stomach conditions relevant to the onset of erosive esophagitis were also analyzed. [Results] The prevalence of reflux erosive esophagitis was 27.2% (118/433; 106 men, 12 women). Visceral fat area was higher in subjects with erosive esophagitis than in those without (116.6 cm2 vs. 64.9 cm2, respectively). The incidence of erosive esophagitis was higher in subjects with visceral fat obesity (visceral fat area ≥ 100 cm2) than in those without (61.2% vs. 12.8%, respectively). Visceral fat obesity had the highest odds ratio (OR) among obesity-related factors. Multivariate analysis showed that visceral fat area was associated with the incidence of erosive esophagitis (OR = 2.18), indicating that it is an independent risk factor for erosive esophagitis. In addition, daily alcohol intake (OR = 1.54), gastric atrophy open type (OR = 0.29), and never-smoking history (OR = 0.49) were also independently associated with the development of erosive esophagitis. [Conclusions] Visceral fat obesity is the key risk factor for the development of reflux erosive esophagitis in subjects aged 40–69 years
Development of a Hierarchy-Integrated Simulation Code for Toroidal Helical Plasmas, TASK3D
The present status of the development of a hierarchy-integrated simulation code for toroidal helical plasmas, TASK3D, is reported. TASK3D is developed by extending the integrated modeling code for tokamak plasmas, Transport Analyzing System for tokamaK (TASK) [A. Fukuyama et al., Proc. of 20th IAEA Fusion Energy Conf. (Villamoura, Portugal, 2004) IAEA-CSP-25/CD/TH/P2-3]. In order to extend TASK to be applicable for threedimensional configurations, a new module for the radial electric field in general toroidal configurations has been developed and implemented. As a first test for this implementation, numerical simulations for the time evolution of temperature and electric field are conducted on the basis of an LHD experimental result, by a successful combination of a diffusive transport module and the implemented electric field module
Comprehensive genomic profiling for patients with chemotherapy‐naïve advanced cancer
Comprehensive genomic profiling (CGP) testing by next-generation sequencing has been introduced into clinical practice as part of precision cancer medicine to select effective targeted therapies. However, whether CGP testing at the time of first-line chemotherapy could be clinically useful is not clear. We conducted this single-center, prospective, observational study to investigate the feasibility of CGP testing for chemotherapy-naïve patients with stage III/IV gastrointestinal cancer, rare cancer, and cancer of unknown primary, using the FoundationOne® companion diagnostic (F1CDx) assay. The primary outcome was the detection rate of at least one actionable/druggable cancer genomic alteration. Actionable/druggable cancer genomic alterations were determined by the F1CDx report. An institutional molecular tumor board determined the molecular-based recommended therapies. A total of 197 patients were enrolled from October 2018 to June 2019. CGP success rate was 76.6% (151 of 197 patients), and median turnaround time was 19 days (range: 10-329 days). Actionable and druggable cancer genomic alterations were reported in 145 (73.6%) and 124 (62.9%) patients, respectively. The highest detection rate of druggable genomic alterations in gastrointestinal cancers was 80% in colorectal cancer (48 of 60 patients). Molecular-based recommended therapies were determined in 46 patients (23.4%). CGP testing would be a useful tool for the identification of a potentially effective first-line chemotherapy
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