178 research outputs found

    X-ray Anomalous Scattering of Diluted Magnetic Oxide Semiconductors: Possible Evidence of Lattice Deformation for High Temperature Ferromagnetism

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    We have examined whether the Co ions crystallographically substitute on the Ti sites in rutile and anatase Ti_{1-x}CoCo_{x}OO_{2-delta}thinfilmsthatexhibitroomtemperatureferromagnetism.IntensitiesofthexrayBraggreflectionfromthefilmsweremeasuredaroundthe thin films that exhibit room-temperature ferromagnetism. Intensities of the x-ray Bragg reflection from the films were measured around the KabsorptionedgeofCo.IftheCoionsrandomlysubstituteontheTisites,theintensityshouldexhibitananomalyduetotheanomalousdispersionoftheatomicscatteringfactorofCo.However,noneoftheanataseandrutilesamplesdidexhibitananomaly,unambiguouslyshowingthattheCoionsinTi-absorption-edge of Co. If the Co ions randomly substitute on the Ti sites, the intensity should exhibit an anomaly due to the anomalous dispersion of the atomic scattering factor of Co. However, none of the anatase and rutile samples did exhibit an anomaly, unambiguously showing that the Co ions in Ti_{1-x}CoCo_{x}OO_{2-delta}arenotexactlylocatedattheTisitesofTiO are not exactly located at the Ti sites of TiO_2.TheabsenceoftheanomalyisprobablycausedbyasignificantdeformationofthelocalstructurearoundCoduetotheoxygenvacancy.WehaveappliedthesamemethodtoparamagneticZn. The absence of the anomaly is probably caused by a significant deformation of the local structure around Co due to the oxygen vacancy. We have applied the same method to paramagnetic Zn_{1-x}CoCo_{x}$O thin films and obtained direct evidence that the Co ions are indeed substituted on the Zn sites.Comment: 5 pages, 4 figures, accepted in PR

    Radiological evaluation of joint space width in medial knee osteoarthritis

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    Background. Although joint space width on weight-bearing radiographs of the knee is critical for early diagnosis and grading knee osteoarthritis, the optimal method with which to accurately measure this value remains controversial. The purpose of this study was to investigate and quantify the effects of the radiographic technique on joint space width in medial knee osteoarthritis.Materials and Methods. We compared maximum plateau gaps and minimum joint space widths on bilateral weight-bearing plain radiographs acquired using three different methods in 31 patients with medial knee osteoarthritis (56 knee joints): standing with the knee extended (standard imaging); SynaFlexer method; and Rosenberg method. Measured values were compared statistically, with values of P < 0.05 considered significant.Results. Maximum plateau gap in the medial compartment was significantly lower with the SynaFlexer method (3.2 ± 1.5 mm) and Rosenberg method (2.2 ± 1.2 mm) than with standard imaging (4.7 ± 2.2 mm; P < 0.05 each). Minimum width of the medial joint space was also significantly lower with the SynaFlexer method (3.1 ± 1.4 mm) and Rosenberg method (2.3 ± 1.4 mm) than with standard imaging (4.1 ± 1.4 mm; P < 0.05 each).Conclusion. The Rosenberg method appears beneficial for diagnosing early knee osteoarthritis, while the SynaFlexer method seems more appropriate for assessing disease severity or progression in patients with painful intermediate to severe knee osteoarthritis

    Stationary waves to viscous heat-conductive gases in half-space: Existence, stability and convergence rate

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    The main concern of this paper is to study large-time behavior of solutions to an ideal polytropic model of compressible viscous gases in one-dimensional half-space. We consider an outflow problem and obtain a convergence rate of solutions toward a corresponding stationary solution. Here the existence of the stationary solution is proved under a smallness condition on the boundary data with the aid of center manifold theory. We also show the time asymptotic stability of the stationary solution under smallness assumptions on the boundary data and the initial perturbation in the Sobolev space, by employing an energy method. Moreover, the convergence rate of the solution toward the stationary solution is obtained, provided that the initial perturbation belongs to the weighted Sobolev space. The proof is based on deriving a priori estimates by using a time and space weighted energy method. © 2010 World Scientific Publishing Company

    Severe Eosinophilia in Myelodysplastic Syndrome With a Defined and Rare Cytogenetic Abnormality

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    Myelodysplastic syndromes (MDS) are a heterogeneous group clonal disorders of hematopoietic stem cells (HSC) characterized by ineffective hematopoiesis that lead to variable grades of impaired blood cell production. Chromosomal aberrations are often detected in MDS patients and thus cytogenetic analysis is useful for the diagnosis of these disorders. Common recurring chromosomal defects, such as the −5/5q- and −7/7q- are relatively well characterized cytogenetic abnormalities in MDS, however, the biological significance of uncommon cytogenetic alterations is unknown. We report here, two cases of peripheral blood and bone marrow hypereosinophilia in patients with MDS harboring the unbalanced translocation der(1;7)(q10;p10), a poorly characterized cytogenetic abnormality that is found in certain myeloid malignancies, including MDS. The patients reported here presented hypereosinophilia that was refractory to steroids and cytotoxic therapy, leading to severe target tissue damage that ultimately resulted in fatal end-organ failure. Potential roles of the der(1;7)(q10;p10) aberrations in the pathogenesis of aggressive eosinophilia and disease prognosis are discussed here
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