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OPTICAL AND NEAR-INFRARED POLARIMETRY FOR A HIGHLY DORMANT COMET 209P/LINEAR
Kuroda, Daisuke,Ishiguro, Masateru,Watanabe, Makoto,Akitaya, Hiroshi,Takahashi, Jun,Hasegawa, Sunao,Ui, Takahiro,Kanda, Yuka,Takaki, Katsutoshi,Itoh, Ryosuke,Moritani, Yuki,Imai, Masataka,Goda, Shuhei IOP Publishing 2015 The Astrophysical journal Vol.814 No.2
<P>We conducted an optical and near-infrared polarimetric observation of the highly dormant Jupiter-Family Comet, 209P/LINEAR. Because of its low activity, we were able to determine the linear polarization degrees of the coma dust particles and nucleus independently, that is P-n = 30.3(-0.9)(+1.3)% at alpha = 92 degrees.2 and P-n = 31.0(-0.7)(+1.0)% at alpha = 99 degrees.5 for the nucleus, and P-c = 28.8(-0.4)(+0.4)% at alpha = 92 degrees.2 and 29.6(-0.3)(+0.3)% at alpha = 99 degrees.5 for the coma. We detected no significant variation in P at the phase angle coverage of 92 degrees.2-99 degrees.5, which may imply that the obtained polarization degrees are nearly at maximum in the phase-polarization curves. By fitting with an empirical function, we obtained the maximum values of linear polarization degrees P-max = 30.8% for the nucleus and P-max = 29.6% for the dust coma. The P-max of the dust coma is consistent with those of dust-rich comets. The low geometric albedo of P-v. =. 0.05 was derived from the slope-albedo relationship and was associated with high P-max. We examined P-max-albedo relations between asteroids and 209P, and found that the so-called Umov law seems to be applicable on this cometary surface.</P>
2014-2015 MULTIPLE OUTBURSTS OF 15P/FINLAY
Ishiguro, Masateru,Kuroda, Daisuke,Hanayama, Hidekazu,Kwon, Yuna Grace,Kim, Yoonyoung,Lee, Myung Gyoon,Watanabe, Makoto,Akitaya, Hiroshi,Kawabata, Koji,Itoh, Ryosuke,Nakaoka, Tatsuya,Yoshida, Michitos American Astronomical Society 2016 The Astronomical journal Vol.152 No.6
<P>Multiple outbursts of a Jupiter-family comet (JFC), 15P/Finlay, occurred from late 2014 to early 2015. We conducted an observation of the comet after the first outburst and subsequently witnessed another outburst on 2015 January 15.6-15.7. The gas, consisting mostly of C-2 and CN, and dust particles expanded at speeds of 1110 +/- 180 m s(-1) and 570 +/- 40 m s(-1) at a heliocentric distance of 1.0 au. We estimated the maximum ratio of solar radiation pressure with respect to the solar gravity beta(max) = 1.6 +/- 0.2, which is consistent with porous dust particles composed of silicates and organics. We found that 10(8)-10(9) kg of dust particles (assumed to be 0.3 mu m - 1 mm) were ejected through each outburst. Although the total mass is three orders of magnitude smaller than that of the 17P/Holmes event observed in 2007, the kinetic energy per unit mass (10(4) J kg(-1)) is equivalent to the estimated values of 17P/Holmes and 332P/2010 V1 (Ikeya-Murakami), suggesting that the outbursts were caused by a similar physical mechanism. From a survey of cometary outbursts on the basis of voluntary reports, we conjecture that 15P/Finlay-class outbursts occur >1.5 times annually and inject dust particles from JFCs and Encke-type comets into interplanetary space at a rate of similar to 10 kg s(-1) or more.</P>
Optical and Near-infrared Polarimetry of Non-periodic Comet C/2013 US10 (Catalina)
Kwon, Yuna Grace,Ishiguro, Masateru,Kuroda, Daisuke,Hanayama, Hidekazu,Kawabata, Koji S.,Akitaya, Hiroshi,Nakaoka, Tatsuya,Itoh, Ryosuke,Toda, Hiroyuki,Yanagisawa, Kenshi,Lee, Myung Gyoon,Ohta, Kouji American Institute of Physics 2017 The Astronomical journal Vol.154 No.4
<P>We present an optical and near-infrared (hereafter NIR) polarimetric study of a comet C/2013 US10 (Catalina) observed on UT 2015 December 17-18 at phase angles of alpha - 52 degrees.1-53 degrees.1. Additionally, we obtained an optical spectrum and multi-band images to examine the influence of gas emission. We find that the observed optical signals are significantly influenced by gas emission; that is, the gas-to-total intensity ratio varies from 5 to 30% in the RC and 3%-18% in the I-C bands, depending on the position in the coma. We derive the 'gas-free dust polarization degrees' of 13.8% +/- 1.0% in the RC and 12.5% +/- 1.1% in the IC bands and a gray polarimetric color, i.e., -8.7% +/- 9.9% mu m(-1) in optical and 1.6% +/- 0.9% mu m(-1) in NIR. The increments of polarization obtained from the gas correction show that the polarimetric properties of the dust in this low-polarization comet are not different from those in high-polarization comets. In this process, the cometocentric distance dependence of polarization has disappeared. We also find that the RC-band polarization degree of the southeast dust tail, which consists of large dust particles (100 mu m(-1) mm), is similar to that in the outer coma where small and large ones are mixed. Our study confirms that the dichotomy of cometary polarization does not result from the difference of dust properties, but from depolarizing gas contamination. This conclusion can provide a strong support for similarity in origin of comets.</P>
Yuma Onoi,Takafumi Hiranaka,Yuichi Hida,Takaaki Fujishiro,Koji Okamoto,Tomoyuki Matsumoto,Ryosuke Kuroda 대한정형외과학회 2022 Clinics in Orthopedic Surgery Vol.14 No.3
Background: To evaluate the clinical outcomes and second-look arthroscopic findings after intra-articular adipose-derived regenerative cell (ADRC) injection as treatment for knee osteoarthritis (OA). Methods: ADRCs were administered to 11 patients (19 knees; mean age, 61.7 years) with knee OA. Subcutaneous adipose tissue was harvested by liposuction from both thighs, and arthroscopic lavage was performed, followed by ADRC injection (mean dose, 1.40 × 107 cells) into the synovial fluid. Outcome measures included the Knee Injury and Osteoarthritis Outcome Score, Lysholm score, and visual analog scale score. Arthroscopic examinations were performed to assess the International Cartilage Repair Society cartilage injury grade preoperatively and overall repair postoperatively. Noninvasive assessments were performed at baseline and at 1-, 3-, and 6-month follow-ups; arthroscopic assessments were performed at baseline and at 6 months. Results: All outcome measures significantly improved after treatment. This improvement was evident 1 month after treatment and was sustained until the 6-month follow-up. Data from second-look arthroscopy showed better repair in low-grade cartilage lesions than in lesions with a greater degree of damage. No patients demonstrated worsening of Kellgren-Lawrence grade, and none underwent total knee arthroplasty during this period. Conclusions: Clinical outcomes were improved in patients with knee OA after ADRC administration. Cartilage regeneration was more effective in smaller damaged lesions than in bigger lesions.
Takahiro Niikura,Sang Yang Lee,Yoshitada Sakai,Kotaro Nishida,Ryosuke Kuroda,Masahiro Kurosaka 대한정형외과학회 2014 Clinics in Orthopedic Surgery Vol.6 No.2
Background: Currently, an algorithmic approach for deciding treatment options according to the Vancouver classification is widely used for treatment of periprosthetic femoral fractures after hip arthroplasty. However, this treatment algorithm based on the Vancouver classification lacks consideration of patient physiology and surgeon’s experience (judgment), which are also important for deciding treatment options. The purpose of this study was to assess the treatment results and discuss the treatment options using a case series. Methods: Eighteen consecutive cases with periprosthetic femoral fractures after total hip arthroplasty and hemiarthroplasty were retrospectively reviewed. A locking compression plate system was used for osteosynthesis during the study period. The fracture type was determined by the Vancouver classification. The treatment algorithm based on the Vancouver classification was generally applied, but was modified in some cases according to the surgeon’s judgment. The reasons for modification of the treatment algorithm were investigated. Mobility status, ambulatory status, and social status were assessed before the fracture and at the latest follow-up. Radiological results including bony union and stem stability were also evaluated. Results: Thirteen cases were treated by osteosynthesis, two by revision arthroplasty and three by conservative treatment. Four cases of type B2 fractures with a loose stem, in which revision arthroplasty is recommended according to the Vancouver classification, were treated by other options. Of these, three were treated by osteosynthesis and one was treated conservatively. The reasons why the three cases were treated by osteosynthesis were technical difficulty associated with performance of revision arthroplasty owing to severe central migration of an Austin-Moore implant in one case and subsequent severe hip contracture and low activity in two cases. The reasons for the conservative treatment in the remaining case were low activity, low-grade pain, previous wiring around the fracture and light weight. All patients obtained primary bony union and almost fully regained their prior activities. Conclusions: We suggest reaching a decision regarding treatment methods of periprosthetic femoral fractures by following the algorithmic approach of the Vancouver classification in addition to the assessment of each patient’s hip joint pathology, physical status and activity, especially for type B2 fractures. The customized treatments demonstrated favorable overall results.
Nobuaki Chinzei,Takafumi Hiranaka,Takahiro Niikura,Mitsuo Tsuji,Ryosuke Kuroda,Minoru Doita,Masahiro Kurosaka 대한정형외과학회 2015 Clinics in Orthopedic Surgery Vol.7 No.3
Background: Recently, various femoral head fixation devices (HFDs) for trochanteric fractures have become available. However, there are some cases in which femoral head rotation with excessive sliding of the HFD is observed and it is often followed by cutout. The purpose of this study is to compare the ability of the three types of HFDs to prevent femoral head rotation. Methods: Between July 2005 and December 2009, 206 patients aged over 60 years with trochanteric fractures who had undergone surgical treatment using a short femoral nail in our institution were enrolled into the study. We used the gamma 3 nail (GMN) as the screw-type HFD in 66 cases, the gliding nail (GLN) as a non-cylindrical blade in 76 cases, and the proximal femoral nail antirotation (PFNA) as a cylindrical blade in 64 cases. The sliding length of HFDs and the occurrence of femoral head rotation were evaluated by assessing radiographs as the main outcome, and the results were compared among these devices. Results: A comparison of the degree of sliding in the GMN group showed that femoral head rotation was observed significantly more frequently in cases with rotation. Further, it appeared that femoral head rotation occurred more frequently in comminuted fractures. However, no significant differences between the sliding lengths of the different HFDs were observed among three groups. Femoral head rotation was observed in 15 cases of GMN (22.7%), 0 case of GLN, and 5 case of PFNA (7.8%). Significant differences with regard to the occurrence of femoral head rotation were observed among the three groups. Furthermore, significant differences were also observed between GLN and PFNA with respect to the occurrence of femoral head rotation. Conclusions: The ability to stabilize femoral head appears to be greater with blade-type materials than with screw-type materials. Furthermore, we believe that a non-cylindrical blade is preferable to a cylindrical blade for the surgical treatment of comminuted, unstable trochanteric fractures in order to prevent femoral head rotation and cut-out.
Wideband InterNetworking Engineering Test and Demonstration Satellite (WINDS) system
Kuramasu, Ryoichi,Araki, Tsunehiko,Shimada, Masaaki,Satoh, Tesuo,Tomita, Eiichi,Futamata, Ryosuke,Kuroda, Tomonori,Yajima, Masanobu,Maeda, Tsuyoshi,Uchida, Hideki,Mukai, Tatsuya,Kadowaki, Naoto,Nakao, 통신위성우주산업연구회 2002 Joint Conference on Satellite Communications Vol.2002 No.-
In April 2001 NASDA launched a new project called "WINDS", Wideband InterNetworking engineering test and Demonstration Satellite, to realize the requirement of Japanese Cabinet IT strategy called "e-Japan Priority Policy Program". The WINDS project is aimed at demonstrating technologies necessary to construct the satellite-based ultra high=speed global fixed wireless communications networks. Based on this objective, NASDA works with CRL to develop the WINDS experiment system to be launched in FY 2005. The WINDS experiment system is planned to demonstrate various experiments, using newly key technology such as multi-beam antenna/multi-port amplifier, Ka band active phased array antenna, on-board ATM switch and so on. This paper describes the concept and outline of the WINDS network experiment system.
( Akiyoshi Mori ),( Takehiko Matsushita ),( Nobuaki Miyaji ),( Kanto Nagai ),( Daisuke Araki ),( Noriyuki Kanzaki ),( Tomoyuki Matsumoto ),( Takahiro Niikura ),( Yuichi Hoshino ),( Ryosuke Kuroda ) 대한슬관절학회 2022 대한슬관절학회지 Vol.34 No.-
Background: Our objective was to evaluate the location of popliteal artery (PA) in osteotomy planes during high tibial osteotomy (HTO) and to determine a safer angle for screw drilling to the tibial tuberosity during distal tuberosity osteotomy (DTO). Methods: Twenty knees in 20 patients who underwent contrast-enhanced computed tomography for cardiovascular diseases were examined. Osteotomy planes for open-wedge HTO (OWHTO) and hybrid closed-wedge HTO (hybrid CWHTO) were created using three-dimensional bone models. The distance from the posterior cortex of the tibia to the PA (dPC-PA) in the osteotomy planes was measured in the virtual osteotomy planes. The dangerous point (Point D1) was defined as the point 17.5 mm away from PA, setting the working length of the bone saw as 35 mm. The distance between the most medial point of the tibial cortex (Point M) and Point D1 in OWHTO and the most lateral point (Point L) and Point D1 in hybrid CWHTO were examined (dM-D1 and dL-D1, respectively). The location of Point D1 to the osteotomy line (%D1) was expressed as percentage, setting the start and end of the osteotomy line as 0% and 100%, respectively. To determine the safe angle for screw drilling in DTO, the angle between the line tangential to the medial cortex of the tibia and that passing through the center of the tibial tuberosity and PA were measured. Results: In OWHTO and hybrid CWHTO, the mean dPC-PA was 10.6 mm (6.9-16.5 mm) and 10.2 mm (7.3-15.4 mm), respectively. The mean dM-D1 in OWHTO was 25.9 mm (24.6-27.2 mm) and dL-D1 in hybrid CWHTO was 5.1 mm (2.9-7.4 mm). The mean %D1 was 47.6 ± 3.7% in OWHTO and 9.3 ± 4.1% in hybrid CWHTO, respectively. The minimal angle between the two lines in DTO was 35.2°. Conclusion: PAs could run within 10 mm from the posterior cortex in the osteotomy planes of HTO. Therefore, proper posterior protection is necessary when cutting posterior cortex. An angle of less than 35° against the medial cortex line would be safe for screw fixation to avoid vascular injury in DTO.