Feasibility of Endoscopic Papillary Large Balloon Dilation in Patients with Difficult Bile Duct Stones without Dilatation of the Lower Part of the Extrahepatic Bile Duct

( Yuji Fujita ),( Akito Iwasaki ),( Takamitsu Sato ),( Toshio Fujisawa ),( Yusuke Sekino ),( Kunihiro Hosono ),( Nobuyuki Matsuhashi ),( Kentaro Sakamaki ),( Atsushi Nakajima ),( Kensuke Kubota ) 대한소화기학회 2017 Gut and Liver Vol.11 No.1

Background/Aims: There is no consensus for using endoscopic papillary large balloon dilation (EPLBD) in patients without dilatation of the lower part of the bile duct (DLBD). We evaluated the feasibility and safety of EPLBD for the removal of difficult bile duct stones (diameter ≥10 mm) in patients without DLBD. Methods: We retrospectively reviewed the records of 209 patients who underwent EPLBD for the removal of bile duct stones from October 2009 to July 2014. Primary outcomes were the clearance rate and additional mechanical lithotripsy. Secondary outcomes were the incidence of complications and recurrence rate. Results: Fiftyseven patients had DLBD (27.3%), and 152 did not have DLBD (72.7%). There were no significant differences in the overall success rate or the use of mechanical lithotripsy. Success rate during the first session and procedure time were better in the DLBD than the without-DLBD group (75.7% vs 66.7%, 48.1±23.0 minutes vs 58.4±31.7 minutes, respectively). As for complications, there were no significant differences in the incidence of pancreatitis, perforation or bleeding after endoscopic retrograde cholangiopancreatography. The recurrence rate did not differ significantly between the two groups. Conclusions: EPLBD is a useful and safe method for common bile duct stone removal in patients without DLBD. (Gut Liver 2017;11:149-155)

Flux Position Estimation Method of IPMSM by Controlling Current Derivative at Zero Voltage Vector

Hosogaya, Yuji,Kubota, Hisao Journal of International Conference on Electrical 2012 Journal of international Conference on Electrical Vol.1 No.1

Various methods have been proposed to identify the flux position in an interior permanent magnet synchronous motor (IPMSM) without the use of mechanical sensors. To achieve this, a method that uses both the back electromotive force (EMF) and the saliency to identify the flux position in the IPMSM without the injection of high-frequency components at low speeds has been reported. This method was then extended in order to drive the motor with no load to a light load. We propose a combination of these methods with different proportional-integral (PI) controllers for controlling $di_{dest}$/dt and $di_{qest}$/dt. We also introduce compensation values $F_L$ and $F_H$ to reduce the position error when the estimation rule is being selected.

DETERMINANTS OF DUAL DISTRIBUTION CHANNELS

Hidesuke Takata,Satoshi Ishikawa,Yuji Kubota,Tetsuo Horiguchi 글로벌지식마케팅경영학회 2014 Global Marketing Conference Vol.2014 No.5

Fluid-Structure Interaction Simulation of Blast Loading

Tei. Saburi,Shiro Kubota,Yuji Ogata 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.11

This paper presents the development of Fluid-Structure Interaction (FSI) coupling code for solving dynamic behavior of structure under blast loading. We have been developed a Semi-Lagrangian CFD code of MARS for solving initiation and detonation phenomena of explosives. In MARS, it is not functional to analyze dynamic structural behavior. A coupling of MARS with Computational Structure Dynamics (CSD) code is sure and steacy way to acquire the capability of the fluid-structure interaction analysis. An explicit Finite-Element Method (FEM) structure solver DYNA3D 2000 is suitable to couple structure solving capability with MARS, so a FSI coupling code for MARS fluid solver and DYNA3D 2000 structure solver was developed. The developed FSI code was adapted to the test problem of dynamic response of the steel pipe under internal blast loading. Air and explosive was modeled using ideal gas EOS and the structure was modeled using Johnson-Cook strength model and Mie-Gruneisen EOS. Explosive has density of 1400 kg/m3 and energy of 5.32 MJ/kg, and other numerical parameters for calculation used typical value. Strain change and radial displacement of circumference were evaluated, and FSI code was validated comparing the numerical results with experimental results.

DETERMINANTS OF DUAL DISTRIBUTION CHANNELS

Hidesuke Takata,Satoshi Ishikawa,Yuji Kubota,Tetsuo Horiguchi 글로벌지식마케팅경영학회 2014 Global Marketing Conference Vol.2014 No.7

Electroded avalanche amorphous selenium (a-Se) photosensor

Oleksandr Bubon,Giovanni DeCrescenzo,Wei Zhao,Yuji Ohkawa,Kazunori Miyakawa,Tomoki Matsubara,Kenji Kikuchi,Kenkichi Tanioka,Misao Kubota,John A. Rowlands,Alla Reznik 한국물리학회 2012 Current Applied Physics Vol.12 No.3

Although avalanche amorphous selenium (a-Se) is a very promising photoconductor for a variety of imaging applications, it is currently restricted to applications with electron beam readout in vacuum pick-up tube called a High-gain Avalanche Rushing Photoconductor (HARP). The electron beam readout is compatible with high definition television (HDTV) applications, but for use in solid-state medical imaging devices it should be replaced by an electronic readout with a two-dimensional array of metal pixel electrodes. However, due to the high electric field required for avalanche multiplication, it is a technological challenge to avoid possible dielectric breakdown at the edges, where electric field experiences local enhancement. It has been shown recently that this problem can be overcome by the use of a Resistive Interface Layer (RIL) deposited between a-Se and the metal electrode, however, at that time, at a sacrifice in transport properties. Here we show that optimization of RIL deposition technique allows for electroded avalanche a-Se with transport properties and time performance previously not achievable with any other a-Se structures. We have demonstrated this by detailed analysis of transport properties performed by Time-of-Flight (TOF)technique. Our results showed that a stable gain of 200 is reached at 104 V/mm for a 15-mm thick a-Se layer, which is the maximum theoretical gain for this thickness. We conclude that RIL is an enabling technology for practical implementation of solid-state avalanche a-Se image sensors. Although avalanche amorphous selenium (a-Se) is a very promising photoconductor for a variety of imaging applications, it is currently restricted to applications with electron beam readout in vacuum pick-up tube called a High-gain Avalanche Rushing Photoconductor (HARP). The electron beam readout is compatible with high definition television (HDTV) applications, but for use in solid-state medical imaging devices it should be replaced by an electronic readout with a two-dimensional array of metal pixel electrodes. However, due to the high electric field required for avalanche multiplication, it is a technological challenge to avoid possible dielectric breakdown at the edges, where electric field experiences local enhancement. It has been shown recently that this problem can be overcome by the use of a Resistive Interface Layer (RIL) deposited between a-Se and the metal electrode, however, at that time, at a sacrifice in transport properties. Here we show that optimization of RIL deposition technique allows for electroded avalanche a-Se with transport properties and time performance previously not achievable with any other a-Se structures. We have demonstrated this by detailed analysis of transport properties performed by Time-of-Flight (TOF)technique. Our results showed that a stable gain of 200 is reached at 104 V/mm for a 15-mm thick a-Se layer, which is the maximum theoretical gain for this thickness. We conclude that RIL is an enabling technology for practical implementation of solid-state avalanche a-Se image sensors.

Evaluating the activity of N-89 as an oral antimalarial drug

Nagwa S. M. Aly,Hiroaki Matsumori,Thi Quyen Dinh,Akira Sato,Shin-Ichi Miyoshi,장경수,유학선,Takaaki Kubota,Yuji Kurosaki,Duc Tuan Cao,Gehan A. Rashed,김혜숙 대한기생충학ㆍ열대의학회 2023 The Korean Journal of Parasitology Vol.61 No.3

Despite the recent progress in public health measures, malaria remains a troublesome disease that needs to be eradicated. It is essential to develop new antimalarial medications that are reliable and secure. This report evaluated the pharmacokinetics and antimalarial activity of 1,2,6,7-tetraoxaspiro[7.11]nonadecane (N-89) using the rodent malaria parasite Plasmodium berghei in vivo. After a single oral dose (75 mg /kg) of N-89, its pharmacokinetic parameters were measured, and t1/2 was 0.97 h, Tmax was 0.75 h, and bioavailability was 7.01%. A plasma concentration of 8.1 ng/ml of N-89 was maintained for 8 h but could not be detected at 10 h. The dose inhibiting 50% of parasite growth (ED50) and ED90 values of oral N-89 obtained following a 4-day suppressive test were 20 and 40 mg/kg, respectively. Based on the plasma concentration of N-89, we evaluated the antimalarial activity and cure effects of oral N-89 at a dose of 75 mg/kg 3 times daily for 3 consecutive days in mice harboring more than 0.5% parasitemia. In all the N-89- treated groups, the parasites were eliminated on day 5 post-treatment, and all mice recovered without a parasite recurrence for 30 days. Additionally, administering oral N-89 at a low dose of 50 mg/kg was sufficient to cure mice from day 6 without parasite recurrence. This work was the first to investigate the pharmacokinetic char-acteristics and antimalarial activity of N-89 as an oral drug. In the future, the following steps should be focused on developing N-89 for malaria treatments; its administration schedule and metabolic pathways should be investigated.