[en] The polarization efficiencies for scattering and the efficiency factors for the differential cross-sections are calculated for several interstellar grain models on the basis of the Mie theory. The results for ice, silicate, and graphite grains are presented in the tabular form, which will be convenient for explaining the observations of polarization in reflection nebulae and in the outer part of galaxies, and so on. (author)

[en] Within the urological field, there are various facilities with regard to imaging diagnosis techniques for kidney disease, in particular renal insufficiency. The present study was carried out to evaluate the accuracy of an imaging technique which does not use contrast media for evaluating complications of blood vessels in chronic renal insufficiency patients, the accuracy of non-invasive imaging techniques for evaluating blood vessels in plural kidney transplantation donors, and the accuracy of imaging techniques for the localization of pathological parathyroid glands. We present an actual case and report the results. We evaluated the accuracy of magnetic resonance angiography (MRA) which did not use any contrast media on the pathological assessment of arterio-venous fistulas in hemodialysis patients. MRA using the time-of-flight technique and phase-contrast technique was not able to provide sufficient information for a pathological assessment of arterio-venous fistulas. Eighteen healthy potential renal donors were prospectively evaluated and underwent donor nephrectomy following helical computed tomography (CT), MDCT (multi-detector row helical CT) and MRA. The vascular findings were compared with the findings on CT, MDCT, MRA and surgery. Nine accessory renal arteries and four accessory renal veins were found at nephrectomy. Renal arteries including accessory renal arteries were detected in 85%, 96% and 96% by helical CT, MDCT and MRA, respectively. Also, the accuracy of identification of renal veins including accessory renal veins with helical CT, MDCT and MRA was 82%, 86% and 82%, respectively. MDCT and MRA were able to provide sufficient information with regard to the renal artery vasculature. Eight secondary hyperparathyroidism patients and one primary hyperparathyroidism patient were evaluated and underwent parathyroidectomy after ultrasonography (USG), CT magnetic resonance imaging (MRI), ^99mTcO₄^- and ²⁰¹TlCl-subtraction scintigraphy, and ^99mTc-sestamibi (MIBI) scintigraphy. The localization of the pathological parathyroid glands was compared based on the findings on USG, CT, MRI, ^99mTcO₄^- and ²⁰¹TlCl-subtraction scintigraphy, ^99mTc-MIBI scintigraphy and surgery. The accuracy of identification of the pathological parathyroids glands with USG, CT, MRI, ^99mTcO₄^- and ²⁰¹TlCl-subtraction scintigraphy, ^99mTc-MIBI scintigraphy was 68%, 70%, 78%, 58% and 50%, respectively. (author)

[en] Optical stellar polarimetry in the Perseus molecular cloud direction is known to show a fully mixed bimodal distribution of position angles across the cloud. We study the Gaia trigonometric distances to each of these stars and reveal that the two components in position angles trace two different dust clouds along the line of sight. One component, which shows a polarization angle of −37.°6 ± 35.°2 and a higher polarization fraction of 2.0 ± 1.7 %, primarily traces the Perseus molecular cloud at a distance of 300 pc. The other component, which shows a polarization angle of +66.°8 ± 19.°1 and a lower polarization fraction of 0.8 ± 0.6 %, traces a foreground cloud at a distance of 150 pc. The foreground cloud is faint, with a maximum visual extinction of ≤1 mag. We identify that foreground cloud as the outer edge of the Taurus molecular cloud. Between the Perseus and Taurus molecular clouds, we identify a lower-density ellipsoidal dust cavity with a size of 100–160 pc. This dust cavity is located at l = 170°, b = −20°, and d = 240 pc, which corresponds to an HI shell generally associated with the Per OB2 association. The two-component polarization signature observed toward the Perseus molecular cloud can therefore be explained by a combination of the plane-of-sky orientations of the magnetic field both at the front and at the back of this dust cavity.