The Incidence of Proximal Extension of Ulcerative Proctitis in Japan and Factors Related to Proximal Extension

The incidence of proximal extension in patients with ulcerative proctitis is reported to be 18%-46%, but recent data on the incidence in Japan is inadequate. The aim of this study was to investigate the incidence of proximal extension of ulcerative proctitis and factors associated with the extension in Japan. This is a retrospective observational study involving a cohort of 53 patients with an initial diagnosis of ulcerative proctitis. Following verification of the diagnoses, demographic and clinical data were compiled. The cumulative incidence of proximal extension was estimated as ‘person-years’ and cumulative probability was calculated by the Kaplan-Meyer method. Univariate and multivariate analyses were performed to identify association factors. During a mean follow-up of 6.8 years, proximal extension was observed in 14 patients (26.4%). The cumulative incidence of proximal extension was 4.22/100 person-years and the cumulative probability at 5 years was 20.1%, consistent with recent reports from Western countries and data obtained in Japan over 2 decades ago. Univariate analysis showed active smoking (P = 0.025) and corticosteroid therapy (P = 0.006) to be risk factors in proximal extension, however multivariate analysis revealed that corticosteroid therapy was the only significant factor (P = 0.005) separating patients with and without proximal extension. No patient underwent colectomy. The incidence of proximal extension in ulcerative proctitis in Japan is comparable to that in Western countries and has not changed significantly over the past two decades. Corticosteroid therapy was identified as the only significant factor in proximal extension

Optical observations of NEA 3200 Phaethon (1983 TB) during the 2017 apparition

The near-Earth asteroid 3200 Phaethon (1983 TB) is an attractive object not only from a scientific viewpoint but also because of JAXA's DESTINY+ target. The rotational lightcurve and spin properties were investigated based on the data obtained in the ground-based observation campaign of Phaethon. We aim to refine the lightcurves and shape model of Phaethon using all available lightcurve datasets obtained via optical observation, as well as our time-series observation data from the 2017 apparition. Using eight 1-2-m telescopes and an optical imager, we acquired the optical lightcurves and derived the spin parameters of Phaethon. We applied the lightcurve inversion method and SAGE algorithm to deduce the convex and non-convex shape model and pole orientations. We analysed the optical lightcurve of Phaethon and derived a synodic and a sidereal rotational period of 3.6039 h, with an axis ratio of a/b = 1.07. The ecliptic longitude (lambda) and latitude (beta) of the pole orientation were determined as (308, -52) and (322, -40) via two independent methods. A non-convex model from the SAGE method, which exhibits a concavity feature, is also presented.Comment: 14 pages, 4 figures, 1 figure in Appendix A. Accepted for publication in Astronomy & Astrophysics (A&A

Photometry and Polarimetry of 2010 XC15_{15}: Observational Confirmation of E-type Near-Earth Asteroid Pair

Asteroid systems such as binaries and pairs are indicative of physical properties and dynamical histories of the Small Solar System Bodies. Although numerous observational and theoretical studies have been carried out, the formation mechanism of asteroid pairs is still unclear, especially for near-Earth asteroid (NEA) pairs. We conducted a series of optical photometric and polarimetric observations of a small NEA 2010 XC$_{15}$ in 2022 December to investigate its surface properties. The rotation period of 2010 XC$_{15}$ is possibly a few to several dozen hours and color indices of 2010 XC$_{15}$ are derived as $g-r=0.435\pm0.008$, $r-i=0.158\pm0.017$, and $r-z=0.186\pm0.009$ in the Pan-STARRS system. The linear polarization degrees of 2010 XC$_{15}$ are a few percent at the phase angle range of 58$^{\circ}$ to 114$^{\circ}$. We found that 2010 XC$_{15}$ is a rare E-type NEA on the basis of its photometric and polarimetric properties. Taking the similarity of not only physical properties but also dynamical integrals and the rarity of E-type NEAs into account, we suppose that 2010 XC$_{15}$ and 1998 WT$_{24}$ are of common origin (i.e., asteroid pair). These two NEAs are the sixth NEA pair and first E-type NEA pair ever confirmed, possibly formed by rotational fission. We conjecture that the parent body of 2010 XC$_{15}$ and 1998 WT$_{24}$ was transported from the main-belt through the $\nu_6$ resonance or Hungaria region.Comment: Resubmitted to AAS Journals. Any comments are welcom