Publications by authors named "Tomohiko Watanabe"

Turbulent transport is a key physics process for confining magnetic fusion plasma. Recent theoretical and experimental studies of existing fusion experimental devices revealed the existence of cross-scale interactions between small (electron)-scale and large (ion)-scale turbulence. Since conventional turbulent transport modelling lacks cross-scale interactions, it should be clarified whether cross-scale interactions are needed to be considered in future experiments on burning plasma, whose high electron temperature is sustained with fusion-born alpha particle heating.

View Article and Find Full Text PDF

Background: The successful intervention for peripheral artery disease is limited by complex chronic total occlusions (CTOs). During CTO wiring, without the use of intravascular or extravascular ultrasound, the guidewire position is unclear, except for calcified lesions showing the vessel path. To solve this problem, we propose a novel guidewire crossing with plaque modification method for complex occlusive lesions, named the "Direct tip Injection in Occlusive Lesions (DIOL)" fashion.

View Article and Find Full Text PDF

Background: Vascular calcification is a predictor of poor clinical outcome during and after endovascular intervention. Guidewire crossing techniques and devices have been developed, but chronic total occlusions (CTOs) with severe calcification often prevent subintimal re-entry. We propose a novel guidewire crossing approach combined needle rendezvous with balloon snare technique, named the "needle re-entry" technique, for treatment of complex occlusive lesions.

View Article and Find Full Text PDF

Objective: Coil embolization (CE) for coronary artery perforation (CAP) has not been thoroughly evaluated. This study aimed to evaluate the extent of myocardial damage and impact on cardiac function after CE for CAP.

Methods: A total of 110 consecutive patients treated with CE for CAP were retrospectively identified.

View Article and Find Full Text PDF

Objectives: Cerebral microbleeds (CMBs), which can be detected by gradient-echo T2*-weighted magnetic resonance imaging (MRI), represent small chronic brain hemorrhages caused by structural abnormalities in cerebral small vessels. CMBs are known to be a potential predictor of future stroke, and are associated with age, various cardiovascular risk factors, cognitive impairment, and the use of antithrombotic drugs. Patients with coronary artery disease (CAD) are at potentially high risk of CMBs due to the presence of coexistent conditions.

View Article and Find Full Text PDF

Unlabelled: Small-scale dynamic auroras have spatial scales of a few km or less, and temporal scales of a few seconds or less, which visualize the complex interplay among charged particles, Alfvén waves, and plasma instabilities working in the magnetosphere-ionosphere coupled regions. We summarize the observed properties of flickering auroras, vortex motions, and filamentary structures. We also summarize the development of fundamental theories, such as dispersive Alfvén waves (DAWs), plasma instabilities in the auroral acceleration region, ionospheric feedback instabilities (IFI), and the ionospheric Alfvén resonator (IAR).

View Article and Find Full Text PDF

Background: Percutaneous coronary intervention (PCI) in hemodialysis patients with severely calcified and diffused lesions is associated with extremely high rates of major adverse cardiovascular events (MACE), even when facilitated by rotational atherectomy (ROTA). Potential risk factors for MACE with ROTA-facilitated PCI in hemodialysis patients should be identified.

Methods: We retrospectively analyzed a consecutive cohort of patients from the Sapporo Cardiovascular Clinic database, who were on maintenance hemodialysis with severe calcified lesions and treated with ROTA-facilitated PCI.

View Article and Find Full Text PDF

Background: This study aimed to clarify the factors for efficient procedures (EP) in superficial femoral artery (SFA) chronic total occlusion (CTO).

Methods: We retrospectively analyzed 200 consecutive limbs that underwent treatment for SFA CTO. The patients were divided into three groups according to the main strategies: subintimal angioplasty (SIA) (n = 123), Crosser use (n = 50), and 0.

View Article and Find Full Text PDF

Drug-eluting stent (DES) is well known to be effective in severely calcified lesion after rotational atherectomy (ROTA). However, there are still some situations when stents should be avoided and plain old balloon angioplasty (POBA) should be the preferred option. The present study aims to explore whether POBA is comparably effective to DES in large and calcified coronary pretreated by ROTA in clinical outcomes.

View Article and Find Full Text PDF

In cartilage tissue engineering, research on materials for three-dimensional (3D) scaffold has attracted attention. Decellularized matrix can be one of the candidates for the scaffold material. In this study, decellularization of regenerated cartilage was carried out and its effectiveness as a scaffold material was examined.

View Article and Find Full Text PDF

Objectives: To introduce a modified rotational atherectomy (RA) procedure and investigate the early and midterm outcomes of the RA-facilitating diversified percutaneous coronary intervention (PCI) in a large group of aged patients with higher cardiovascular risk.

Background: Previous studies about the outcomes of RA were limited with small sample size and low-risk population.

Methods: Between January 2013 and November 2015, 1169 consecutive patients treated with modified RA-facilitated PCI were retrospectively enrolled, including de novo calcified lesions and in-stent restenosis.

View Article and Find Full Text PDF

Gradient-echo T2-star (T2*)-weighted magnetic resonance imaging (MRI) is a sensitive method to detect cerebral microbleeds (CMBs). The presence of CMBs was reported to be a marker of future cardiovascular mortality and is associated with various cardiovascular risk factors, use of antithrombotic drugs, and cognitive dysfunction. However, the relationship between cardiac function and CMBs remains unclear.

View Article and Find Full Text PDF

Background: Although bioresorbable polymer sirolimus-eluting Ultimaster stents (BP-SESs) are likely useful for percutaneous coronary interventions (PCIs), the clinical data from real-world cases are insufficient. Furthermore, the predictors of adverse clinical outcomes after BP-SES implantation have not been fully investigated.

Objectives: This study evaluated the 1-year clinical outcomes after BP-SES implantation in real-world PCI cases and identified the predictors of adverse outcomes.

View Article and Find Full Text PDF

Purpose: Our institution employs rectoplasty with a posterior triangular colonic flap (RPTCF) for classic-type Hirschsprung's disease. Recently, we employed a modified Soave procedure: transanal endorectal pull-through with rectoanal myotomy (TEPTRAM). In both procedures, the internal sphincter muscle is completely divided vertically at the 6 o'clock position.

View Article and Find Full Text PDF

Objectives: This study aimed to evaluate the outcomes of patients with in-stent restenosis (ISR) who underwent rotablation (RA) followed by balloon angioplasty (BA), drug-eluting stent (DES) implantation, or drug-coated balloon (DCB) angioplasty.

Background: Interventional treatment of ISR is occasionally challenging. Despite the availability of various percutaneous treatments, the optimal solution remains unclear.

View Article and Find Full Text PDF

Objectives: The aim of this study was to evaluate the clinical outcomes of rotational atherectomy (RA) followed by new-generation drug-eluting stent (DES) implantation in patients with an extensive amount of calcified and fibrotic plaque.

Background: RA followed by new-generation DES implantation for complex lesions has not been thoroughly evaluated.

Methods: A total of 744 consecutive patients (770 lesions) treated with new-generation DES implantation following RA for de novo lesions between January 2013 and November 2015 were retrospectively identified using our institutional database.

View Article and Find Full Text PDF

Impacts of isotope ion mass on trapped-electron-mode (TEM)-driven turbulence and zonal flows in magnetically confined fusion plasmas are investigated. Gyrokinetic simulations of TEM-driven turbulence in three-dimensional magnetic configuration of helical plasmas with hydrogen isotope ions and real-mass kinetic electrons are realized for the first time, and the linear and the nonlinear nature of the isotope and collisional effects on the turbulent transport and zonal-flow generation are clarified. It is newly found that combined effects of the collisional TEM stabilization by the isotope ions and the associated increase in the impacts of the steady zonal flows at the near-marginal linear stability lead to the significant transport reduction with the opposite ion mass dependence in comparison to the conventional gyro-Bohm scaling.

View Article and Find Full Text PDF

Strangulated intestinal obstruction is one of the most common types of acute abdomen and requires urgent surgical treatment. Herein, we report a very rare case of strangulated intestinal obstruction caused by an ileo-ileal knot. An 80-year-old woman was admitted to our hospital with suspicion of strangulation ileus and underwent emergency laparotomy after investigation by exploratory single-port laparoscopy.

View Article and Find Full Text PDF

Background: We assessed the long-term outcomes of patients with biliary atresia with splenic malformation (BASM).

Methods: We retrospectively assessed outcomes of 255 patients who underwent the Kasai procedure (KP) at our hospital between 1972 and 2014. Clinical outcomes of 11 patients with BASM (group A: nine with polysplenia, two with asplenia) and 244 patients with isolated BA (group B) were compared.

View Article and Find Full Text PDF

Mach-Zehnder optical modulators are the key devices for high-speed electrical-to-optical conversion in Si photonics. Si rib waveguides with a p-n diode structure operated in the carrier depletion mode have mainly been developed as their phase shifters. Their length is usually longer than millimeters due to the limited change in the refractive index due to the carrier depletion in a Si p-n diode.

View Article and Find Full Text PDF

A 57 year-old man presenting with acute inferior myocardial infarction underwent percutaneous coronary intervention. Following the placement of TAXUS Liberte 2.5 × 24 mm (Boston Sientific, USA), for 99% stenosis with delay, severe vasospasm occurred at distal portion of the stent.

View Article and Find Full Text PDF