94 research outputs found

    Proton Irradiation Experiment for the X-ray Charge-Coupled Devices of the Monitor of All-sky X-ray Image mission onboard the International Space Station: I. Experimental Setup and Measurement of the Charge Transfer Inefficiency

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    We have investigated the radiation damage effects on a CCD to be employed in the Japanese X-ray astronomy mission including the Monitor of All-sky X-ray Image (MAXI) onboard the International Space Station (ISS). Since low energy protons release their energy mainly at the charge transfer channel, resulting a decrease of the charge transfer efficiency, we thus focused on the low energy protons in our experiments. A 171 keV to 3.91 MeV proton beam was irradiated to a given device. We measured the degradation of the charge transfer inefficiency (CTI) as a function of incremental fluence. A 292 keV proton beam degraded the CTI most seriously. Taking into account the proton energy dependence of the CTI, we confirmed that the transfer channel has the lowest radiation tolerance. We have also developed the different device architectures to reduce the radiation damage in orbit. Among them, the ``notch'' CCD, in which the buried channel implant concentration is increased, resulting in a deeper potential well than outside, has three times higher radiation tolerance than that of the normal CCD. We then estimated the charge transfer inefficiency of the CCD in the orbit of ISS, considering the proton energy spectrum. The CTI value is estimated to be 1.1e-5 per each transfer after two years of mission life in the worse case analysis if the highest radiation-tolerant device is employed. This value is well within the acceptable limit and we have confirmed the high radiation-tolerance of CCDs for the MAXI mission.Comment: 17 pages, 2 table, 12 figures. Accepted for publication of Japanese Journal of Applied Physics. High resolution file is available from http://wwwxray.ess.sci.osaka-u.ac.jp/~miyata/paper/proton_cti.pd

    Cost-effective learning for classifying human values

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    Prior work has found that classifier accuracy can be improved early in the process by having each annotator label different documents, but that later in the process it becomes better to rely on a more expensive multiple-annotation process in which annotators subsequently meet to adjudicate their differences. This paper reports on a study with a large number of classification tasks, finding that the relative advantage of adjudicated annotations varies not just with training data quantity, but also with annotator agreement, class imbalance, and perceived task difficulty

    Low visual information-processing speed and attention are predictors of fatigue in elementary and junior high school students

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    Background: Fatigue is a common complaint among elementary and junior high school students, and is known to be associated with reduced academic performance. Recently, we demonstrated that fatigue was correlated with decreased cognitive function in these students. However, no studies have identified cognitive predictors of fatigue. Therefore, we attempted to determine independent cognitive predictors of fatigue in these students.Methods: We performed a prospective cohort study. One hundred and forty-two elementary and junior high school students without fatigue participated. They completed a variety of paper-and-pencil tests, including list learning and list recall tests, kana pick-out test, semantic fluency test, figure copying test, digit span forward test, and symbol digit modalities test. The participants also completed computerized cognitive tests (tasks A to E on the modified advanced trail making test). These cognitive tests were used to evaluate motor-and information-processing speed, immediate and delayed memory function, auditory and visual attention, divided and switching attention, retrieval of learned material, and spatial construction. One year after the tests, a questionnaire about fatigue (Japanese version of the Chalder Fatigue Scale) was administered to all the participants.Results: After the follow-up period, we confirmed 40 cases of fatigue among 118 students. In multivariate logistic regression analyses adjusted for grades and gender, poorer performance on visual information-processing speed and attention tasks was associated with increased risk of fatigue.Conclusions: Reduced visual information-processing speed and poor attention are independent predictors of fatigue in elementary and junior high school students

    Reduced dose of PTCy followed by adjuvant alpha-galactosylceramide enhances GVL effect without sacrificing GVHD suppression

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    Posttransplantation cyclophosphamide (PTCy) has become a popular option for haploidentical hematopoietic stem cell transplantation (HSCT). However, personalized methods to adjust immune intensity after PTCy for each patient's condition have not been well studied. Here, we investigated the effects of reducing the dose of PTCy followed by alpha -galactosylceramide (alpha -GC), a ligand of iNKT cells, on the reciprocal balance between graft-versus-host disease (GVHD) and the graft-versus-leukemia (GVL) effect. In a murine haploidentical HSCT model, insufficient GVHD prevention after reduced-dose PTCy was efficiently compensated for by multiple administrations of alpha -GC. The ligand treatment maintained the enhanced GVL effect after reduced-dose PTCy. Phenotypic analyses revealed that donor-derived B cells presented the ligand and induced preferential skewing to the NKT2 phenotype rather than the NKT1 phenotype, which was followed by the early recovery of all T cell subsets, especially CD4(+)Foxp3(+) regulatory T cells. These studies indicate that alpha -GC administration soon after reduced-dose PTCy restores GVHD-preventing activity and maintains the GVL effect, which is enhanced by reducing the dose of PTCy. Our results provide important information for the development of a novel strategy to optimize PTCy-based transplantation, particularly in patients with a potential relapse risk

    A Rare Case Oesophageal Perforation by a Fish Bone, Leading to Pericardial Penetration and Cardiac Tamponade

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    An 82-year-old woman swallowed a fish bone and presented to our hospital 3 days later when she had breathing difficulty and became hypotensive. Chest computed tomography (CT) showed a linear structure with high bone density extending from the oesophagus into the pericardium, along with pericardial effusion, air, and a left pleural effusion. We diagnosed the patient with oesophageal perforation by a foreign body (a fish bone) leading to pericardial penetration, cardiac tamponade, and left empyema. The patient underwent emergency surgery. Pericardial fenestration and drainage of the pericardial and thoracic cavities were performed. Chest CT showed a recurrent abscess cavity in the pericardium on day 6. A pigtail catheter was placed in the recurrent abscess cavity under CT guidance for drainage. The patient gradually improved and was discharged after 5 months

    A Report on Overseas Teaching Practicum by Graduate Students in Elementary/Secondary Schools in the United States (XII)

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    This paper reports on the overseas teaching practicum in the U.S., which was supposed to be the 12th time this year. Eight students joined this year’s program and they prepared for the practicum in the U.S. They met regularly to discuss the lesson plans and deepen their understanding on how to create a lesson and what scaffolding steps they should prepare for conveying messages to American children who know little about Japanese culture and having different background from us. Unfortunately, just a few days before the departure, we had to give up our visit to the U.S. since there was a high chance of a hurricane hitting the area we were to visit. Though we could not make our visit in September, instead we held a forum in November and exchanged discussion on the impact of the program to the participants and the schools which accept us. The details of the lesson plans and the forum are reported in this paper

    Index markers of chronic fatigue syndrome with dysfunction of TCA and urea cycles

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    Chronic fatigue syndrome (CFS) is a persistent and unexplained pathological state characterized by exertional and severely debilitating fatigue, with/without infectious or neuropsychiatric symptoms, lasting at least 6 consecutive months. Its pathogenesis remains incompletely understood. Here, we performed comprehensive metabolomic analyses of 133 plasma samples obtained from CFS patients and healthy controls to establish an objective diagnosis of CFS. CFS patients exhibited significant differences in intermediate metabolite concentrations in the tricarboxylic acid (TCA) and urea cycles. The combination of ornithine/citrulline and pyruvate/isocitrate ratios discriminated CFS patients from healthy controls, yielding area under the receiver operating characteristic curve values of 0.801 (95% confidential interval [CI]: 0.711–0.890, P < 0.0001) and 0.750 (95% CI: 0.584–0.916, P = 0.0069) for training (n = 93) and validation (n = 40) datasets, respectively. These findings provide compelling evidence that a clinical diagnostic tool could be developed for CFS based on the ratios of metabolites in plasma

    Dielectrophoresis Conditions for Pearl Chain Formation and Effect of Pulse Field Strength on Protoplast Breakdown of Hericium erinaceum

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    The fusion method using PEG as a fusogenic agent has a number of disadvantages in comparison with the newly developed electrical fusion method. However, there has been little application yet of this electrical fusion method to the fusion of protoplasts of mushrooms. In this report, we describe the pearl chain formation and effect of pulse field strength on protoplast breakdown of protoplasts prepared from Hericium erinaceum. The protoplasts density favorable for pearl chain formation was about 10^8protoplasts/ml, and the yield of single pairs was maximum (30%) after 60sec dielectrophoresis at 100V/cm and 1MHz. The field intensity required to decompose half of the protoplast from H. erinaceum was 8kV/cm in a 0.7M mannitol solution

    Effect of culture broths from various microorganisms on fruiting of Pleurotus ostreatus W0001

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    We report the effect of culture broths from various microorganisms on fruiting of Pleurotus ostreatus W0001. P. ostreatus W0001 has been grown on sterile sawdust medium containing culture broths from various microorganisms with good yields in small scale experiments. The spawning to first yield obtained for a period of 10 days was 9.7% of the moistened medium on the sawdusts medium containing culture broth from Saccharomyces cerevisiae AKU 4100
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