126 research outputs found

    Possible superconductivity above 25 K in single crystalline Co-doped BaFe2_{2}As2_{2}

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    We present superconducting properties of single crystalline Ba(Fe0.9_{0.9}Co0.1_{0.1})2_{2}As2_{2} by measuring magnetization, resistivity, upper critical field, Hall coefficient, and magneto-optical images. The magnetization measurements reveal fish-tail hysteresis loop at high temperatures and relatively high critical current density above Jc=105J_{c}=10^{5} A/cm2^{2} at low temperatures. Upper critical field determined by resistive transition is anisotropic with anisotropic parameter \sim 3.5. Hall effect measurements indicate that Ba(Fe0.9_{0.9}Co0.1_{0.1})2_{2}As2_{2} is a multiband system and the mobility of electron is dominant. The magneto-optical imaging reveals prominent Bean-like penetration of vortices although there is a slight inhomogeneity in a sample. Moreover, we find a distinct superconductivity above 25 K, which leads us to speculate that higher transition temperature can be realized by fine tuning Co-doping level.Comment: 4 pages, 5 figure

    Study of quantum effects on atomic displacements in quartz

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    金沢大学理工研究域数物科学系The crystal structure of quartz (SiO2) was analyzed by neutron powder diffraction at several temperatures in the range of 10–250 K. The temperature dependence of the structure parameters was consistent with our previous results obtained using single-crystal X-ray diffraction above room temperature. Atomic displacements are order parameters for displacive structural phase transitions. The temperature evolution of Si atomic displacement in quartz was analyzed by studying the quantum expansion of the Landau potential. The expansion was found to accurately describe the evolution of the atomic displacement over the entire temperature interval. To the best of our knowledge, such a verification of atomic displacement is the first of its kind. A proportional relationship between spontaneous strain and the square of the atomic displacement was observed over the entire temperature interval. The validity of the obtained characteristic temperature for the quantum effect is discussed and compared with the results of previous Raman-scattering studies

    Videofluorographic Evaluation of Mastication and Swallowing of Japanese Udon Noodles and White Rice

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    A videofluorographic (VF) swallowing study was performed on 22 healthy volunteers to observe the complete mastication and swallowing phases for Japanese udon noodles and white rice. The hardness, stickiness, and cohesiveness of food samples were measured using a food texture analyzing system. VF images were acquired using a versatile fluoroscopic unit and barium sulfate was used as a contrast medium. Udon noodles had a harder and smoother food texture than white rice. Fewer chewing movements and more stage 2 transport were seen during the consumption of udon noodles than for white rice

    Sub-millimeter Observations of Giant Molecular Clouds in the Large Magellanic Cloud: Temperature and Density as Determined from J=3-2 and J=1-0 transitions of CO

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    We have carried out sub-mm 12CO(J=3-2) observations of 6 giant molecular clouds (GMCs) in the Large Magellanic Cloud (LMC) with the ASTE 10m sub-mm telescope at a spatial resolution of 5 pc and very high sensitivity. We have identified 32 molecular clumps in the GMCs and revealed significant details of the warm and dense molecular gas with n(H2) \sim 1035^{3-5} cm3^{-3} and Tkin \sim 60 K. These data are combined with 12CO(J=1-0) and 13CO(J=1-0) results and compared with LVG calculations. We found that the ratio of 12CO(J=3-2) to 12CO(J=1-0) emission is sensitive to and is well correlated with the local Halpha flux. We interpret that differences of clump propeties represent an evolutionary sequence of GMCs in terms of density increase leading to star formation.Type I and II GMCs (starless GMCs and GMCs with HII regions only, respectively) are at the young phase of star formation where density does not yet become high enough to show active star formation and Type III GMCs (GMCs with HII regions and young star clusters) represents the later phase where the average density is increased and the GMCs are forming massive stars. The high kinetic temperature correlated with \Halpha flux suggests that FUV heating is dominant in the molecular gas of the LMC.Comment: 74 pages, including 41 figures, accepted for publication in ApJ

    Photon Dominated Regions in NGC 3603

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    Aims: We aim at deriving the excitation conditions of the interstellar gas as well as the local FUV intensities in the molecular cloud surrounding NGC 3603 to get a coherent picture of how the gas is energized by the central stars. Methods: The NANTEN2-4m submillimeter antenna is used to map the [CI] 1-0, 2-1 and CO 4-3, 7-6 lines in a 2' x 2' region around the young OB cluster NGC 3603 YC. These data are combined with C18O 2-1 data, HIRES-processed IRAS 60 and 100 micron maps of the FIR continuum, and Spitzer/IRAC maps. Results: The NANTEN2 observations show the presence of two molecular clumps located south-east and south-west of the cluster and confirm the overall structure already found by previous CS and C18O observations. We find a slight position offset of the peak intensity of CO and [CI], and the atomic carbon appears to be further extended compared to the molecular material. We used the HIRES far-infrared dust data to derive a map of the FUV field heating the dust. We constrain the FUV field to values of \chi = 3 - 6 \times 10^3 in units of the Draine field across the clouds. Approximately 0.2 to 0.3 % of the total FUV energy is re-emitted in the [CII] 158 {\mu}m cooling line observed by ISO. Applying LTE and escape probability calculations, we derive temperatures (TMM1 = 43 K, TMM2 = 47 K), column densities (N(MM1) = 0.9 \times 10^22 cm^-2, N(MM2) = 2.5 \times 10^22 cm^-2) and densities (n(MM1) = 3 \times 10^3 cm^-3, n(MM2) = 10^3 -10^4 cm^-3) for the two observed molecular clumps MM1 and MM2. Conclusions: The cluster is strongly interacting with the ambient molecular cloud, governing its structure and physical conditions. A stability analysis shows the existence of gravitationally collapsing gas clumps which should lead to star formation. Embedded IR sources have already been observed in the outskirts of the molecular cloud and seem to support our conclusions.Comment: 13 pages, 10 figures, accepted for publication by A&

    Acute adrenal crisis after orthopedic surgery for pathologic fracture

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    BACKGROUND: Adrenal crisis after surgical procedure is a rare but potentially catastrophic life-threatening event. Its manifestations, such as hypotension, tachycardia, hypoxia, and fever mimic the other more common postoperative complications. Clinical outcome is dependent upon early recognition of the condition and proper management with exogenous steroid administration. CASE PRESENTATION: We report a 75-year-old man who presented with shock immediately after surgery for a femoral fracture from lung cancer metastasis. Anemia and severe hyponatremia were detected. Despite adequate fluid resuscitation, nonspecific symptoms including hypotension, tachycardia, hypoxia, fever and confusion occurred. Emergent CT revealed enlarged bilateral adrenal glands. Under the diagnosis of adrenal crisis due to metastatic infiltration of adrenal glands, the patient was treated with appropriate steroid replacement resulting in rapid improvement and recovery. CONCLUSION: We describe a case of adrenal crisis caused by the lack of adrenal reserve based on metastatic involvement and surgical stress, the first published case of adrenal crisis after surgery for a pathologic fracture from lung cancer metastasis. Surgeons treating pathologic fractures should be aware of this complication and familiar with its appropriate therapy because of increasing opportunity to care patients with metastatic bone tumors due to recent advances in cancer treatment

    Effect of anisotropic impurity scattering in superconductors

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    We discuss the weak-coupling BCS theory of a superconductor with the impurities, accounting for their anisotropic momentum-dependent potential. The impurity scattering process is considered in the t-matrix approximation and its influence on the superconducting critical temperature is studied in the Born and unitary limit for a d- and (d+s)-wave superconductors. We observe a significant dependence of the pair-breaking strength on the symmetry of the scattering potential and classify the impurity potentials according to their ability to alter T_c. A good agreement with the experimental data for Zn doping and oxygen irradiation in the overdoped cuprates is found.Comment: 31 pages, RevTex, 15 PostScript figure

    Thymoma calcification: Is it clinically meaningful?

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    Among anterior mediastinal lesions, thymoma is the most common. Thymomas are tumors of thymic epithelial cell origin that are distinguished by inconsistent histological and biologic behavior. Chest imaging studies typically show a round or lobulated tumor in the anterior mediastinum. Calcifications in thymomas are classically punctuate or amorphous, positioned within the lesion. Chest computed tomography (CT) features suggesting higher risk thymoma consist of tumor heterogeneity, vascular involvement, lobulation, pulmonary nodules, lymphadenopathy, and pleural manifestations. Imaging findings have an imperfect ability to predict stage and prognosis for thymoma patients. Our objective is to highlight the clinical implications of thymoma calcifications on the diagnosis, clinical manifestation and prognosis. A pubmed and google search was performed using the following words: thymoma calcification, calcified thymus, mediastinal calcification, anterior mediastinal calcification, and calcified thymoma. After reviewing 370 articles, 32 eligible articles describing thymoma calcifications were found and included in this review. Although the presence of thymus calcifications was more common in patients with invasive thymomas, they were present in significant portion of non-invasive thymomas. The presence of calcifications was not a significant factor in differentiating between benign and malignant thymoma. As a result, the type, location, size or other characteristics of thymus gland calcifications were not relevant features in clinical and radiologic diagnosis of thymoma. The histopathological diagnosis is still the only possible way to confirm the neoplastic nature of thymoma. All types of thymomas should be evaluated and managed independently of the presence of calcifications

    Cell proliferation effect of GnRH agonist on pathological lesions of women with endometriosis, adenomyosis and uterine myoma.

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    BACKGROUND: We recently demonstrated the effect of gonadotrophin-releasing hormone agonist (GnRHa) on tissue inflammation, angiogenesis and apoptosis in endometriosis, adenomyosis and uterine myoma. Here, we investigated expression of GnRH receptors (GnRHRs) and effect of GnRHa on the proliferation of cells derived from endometria and pathological lesions of women with these reproductive diseases. METHODS: Biopsy specimens were collected from lesions and corresponding endometria of 35 women with pelvic endometriosis, 45 women with ovarian endometrioma, 35 women with adenomyosis and 56 women with uterine myoma during laparoscopy or laparotomy. The gene and protein expressions of GnRHR in eutopic/ectopic cells and tissues were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. The immunoreactivity of GnRHR in tissue was analysed by quantitative-histogram (Q-H) scores. The exogenous effect of GnRHa on cell proliferation was examined by 5-bromo-2-deoxyuridine incorporation assay. The Ki-67-immunoreactive cell proliferation index was analysed in biopsy specimens derived from GnRHa-treated and -non-treated women. RESULTS: Types I and II GnRHRs mRNA and proteins were expressed in eutopic endometria and pathological lesions derived from women with endometriosis, adenomyosis and uterine myoma. GnRHR expression was the highest in the menstrual phase when compared with other phases of the menstrual cycle. Higher Q-H scores of GnRHR immunoreaction were found in blood-filled opaque red lesions than in other peritoneal lesions. Exogenous treatment with GnRHa significantly suppressed the proliferation of cells derived from respective endometria and pathological lesions when compared with GnRHa-non-treated cells. CONCLUSIONS: Local tissue expression of GnRHR was detected in endometriosis, adenomyosis and uterine myoma. In addition to a hypo-estrogenic effect, a direct anti-proliferative effect of GnRHa may be involved in the regression of these reproductive diseases with consequent remission of clinical symptoms
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