276 research outputs found

    Complex Impedance Measurements on the Steady State Behaviors of a 10-cell PEFC Stack

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    Experimental studies on the behavior of a Polymer Electrolyte Fuel Cell (PEFC) stack were conducted by performing complex impedance measurements. Initially, the steady state characteristics of a 10-cell stack were measured, and the power function of the DC current was obtained to represent these characteristics. The frequency properties of the complex impedance apparatus were investigated in order to clarify the limitations of frequency measurement. The components of complex impedance, the real and imaginary parts, were rearranged into two vectors to analyze their frequency responses to power and output DC current

    Ectopic varices in a right diaphragm that ruptured into the pleural cavity.

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    The term ectopic varices is used to describe dilated portosystemic collateral veins in unusual locations other than the gastroesophageal region. We recently experienced a rare case of ectopic varices that developed in the right diaphragm and ruptured into the pleural cavity. A 68-year-old female with hepatocellular carcinoma complicated with liver cirrhosis was admitted due to an acute onset of dyspnea and right bloody pleural effusion. Because of the patient's advanced hepatocellular carcinoma and poor condition, conservative therapies such as hemostats and blood transfusion were selected. Even though the bleeding to the pleural cavity stopped spontaneously, the patient died due to a progression of liver failure. Autopsy revealed a huge collateral vein in the right diaphragm. The etiology, prevalence, relationship with portal hypertension, and treatment of ectopic varices are discussed herein

    Inter-impurity and impurity-host magnetic correlations in semiconductors with low-density transition-metal impurities

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    Experiments on (Ga,Mn)As in the low-doping insulating phase have shown evidence for the presence of an impurity band at 110 meV above the valence band. The motivation of this paper is to investigate the role of the impurity band in determining the magnetic correlations in the low-doping regime of the dilute magnetic semiconductors. For this purpose, we present results on the Haldane-Anderson model of transition-metal impurities in a semiconductor host, which were obtained by using the Hirsch-Fye Quantum Monte Carlo (QMC) algorithm. In particular, we present results on the impurity-impurity and impurity-host magnetic correlations in two and three-dimensional semiconductors with quadratic band dispersions. In addition, we use the tight-binding approximation with experimentally-determined parameters to obtain the host band structure and the impurity-host hybridization for Mn impurities in GaAs. When the chemical potential is located between the top of the valence band and the impurity bound state (IBS), the impurities exhibit ferromagnetic (FM) correlations with the longest range. We show that these FM correlations are generated by the antiferromagnetic coupling of the host electronic spins to the impurity magnetic moment. Finally, we obtain an IBS energy of 100 meV, which is consistent with the experimental value of 110 meV, by combining the QMC technique with the tight-binding approach for a Mn impurity in GaAs.Comment: 12 pages, 16 figure

    A Study on the Incidence and Comorbidities of Autism Spectrum Disorders Accompanied by Intellectual Disabilities in Yonago City, Japan

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    [Background] Autism spectrum disorders (ASD) with intellectual disabilities may be associated with many factors. This study focused on patients with ASD with intellectual disabilities, defined by a threshold intelligence quotient (IQ) or development quotient (DQ) of 70. We also discuss comorbidities and other factors related to ASD. [Methods] We extracted case records of patients born between April 1995 and March 2001 who lived in Yonago City, as of January 2011, and had visited the two specialist institutions for consultation regarding developmental issues. The list was further narrowed down to patients identified, as having ASD by pediatric neurologists based on Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-5). We selected patients with < IQ/DQ 70 using the most recent intelligence/development test to determine comorbidities and other factors related to ASD. [Results] The data of 81 patients (59 males and 22 females) were extracted, corresponding to an incidence of 76.2 patients out of every 10,000 births. The male-to-female ratio was 2.7:1. Comorbidities and related factors of ASD were observed in 25 cases (30.9%). Eleven cases had perinatal abnormalities. Other abnormalities were observed in 17 cases, including epilepsies in 7, chromosomal abnormalities in 4, familial mental retardation in 1, and acquired brain injury in 1. [Conclusion] It is important to treat and support individuals with ASD and intellectual disabilities taking into account the characteristics and prognosis of the comorbidities and related factors

    DC superconducting quantum interference devices fabricated using bicrystal grain boundary junctions in Co-doped BaFe2As2 epitaxial films

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    DC superconducting quantum interference devices (dc-SQUIDs) were fabricated in Co-doped BaFe2As2 epitaxial films on (La, Sr)(Al, Ta)O3 bicrystal substrates with 30deg misorientation angles. The 18 x 8 micro-meter^2 SQUID loop with an estimated inductance of 13 pH contained two 3 micro-meter wide grain boundary junctions. The voltage-flux characteristics clearly exhibited periodic modulations with deltaV = 1.4 micro-volt at 14 K, while the intrinsic flux noise of dc-SQUIDs was 7.8 x 10^-5 fai0/Hz^1/2 above 20 Hz. The rather high flux noise is mainly attributed to the small voltage modulation depth which results from the superconductor-normal metal-superconductor junction nature of the bicrystal grain boundary

    Cerebellar Ganglioglioma in Childhood: Histopathologic Implications for Management During Long-term Survival: A Case Report

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    We report the case of a 19-year-old female with cerebellar ganglioglioma that was diagnosed at 4 years of age. Despite treatment with partial resection, radiation, and chemotherapy, residual tumor slowly expanded into the brainstem and upper cervical cord, resulting in nocturnal hypopnea, progressive tetraparesis, and feeding difficulty during 8?10 years of age. Initiation of temozolomide and bevacizumab was effective in preventing further expansion of the tumor, and the patient has been treated at home and in school with noninvasive positive pressure ventilation and gastrostomy. Histopathologic examination of the resected tumor tissue revealed phospho-S6-positive tumor cells of either neuronal or astroglial appearance. This suggests that a higher proportion of cells of glial lineage could be linked to the progression of cerebellar ganglioglioma in childhood. Possible treatment options with mammalian target of rapamycin inhibitors are discussed

    The abscopal effect induced by in situ-irradiated peripheral tumor cells in a murine GL261 brain tumor model

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    Background: Localized radiotherapy is considered to act as an adjuvant for systemic anti-tumor immunity. We examined whether in situ-irradiated peripheral tumor cells can evoke an abscopal effect in the brain inhibiting malignant tumor growth.Methods: Syngeneic albino C57BL/6 mice were inoculated with mouse glioma cells (GL261) transfected with the Kusabira Orange fluorescent gene (GL261-mKO) for monitoring the tumor growth with in vivo imaging system. GL261-mKO cells were subcutaneously implanted in the thigh and irradiated by X-rays (20 Gy) for in situ vaccination. Ex vivo-irradiated GL261-mKO cells were used as a conventional whole-cell vaccine for comparison. Following these treatments, the brain was challenged with the same GL261-mKO cells, and survival analyses were performed by Kaplan-Meier analysis. In addition, IFN-γ release from splenocytes and CD8+ cells infiltration into the brain were analyzed.Results: Both in situ- and ex vivo-irradiated vaccines significantly prolonged the survival of the mice compared to the control group bearing an intracerebral tumor. Although there was no significant difference in survival between the two vaccination methods, in situ-vaccinated mice with local control by irradiation completely rejected the implanted tumor cells in the brain. In contrast, mice with local failure demonstrated a rapid growth of both subcutaneous and challenged intracerebral tumors. The cured mice demonstrated an accumulation of CD8+ cells surrounding the inoculation site, as well as increased release of IFN-γ via an ELISPOT assay.Conclusions: Our results indicate that the X-ray irradiation to peripheral tumors evoked a protective, tumor-specific immune response in the brain when the peripheral tumors were successfully cured by irradiation
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