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Search Results: 1 - 10 of 1583 matches for " Hiroaki Arakawa "
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Simplified Bernoulli Formula to Diagnose Ischemia-Causing Stenosis at Coronary CT Angiography: Comparison with SPECT  [PDF]
Nobuo Tomizawa, Hiroaki Arakawa, Kodai Yamamoto, Shinichi Inoh, Takeshi Nojo, Sunao Nakamura
Advances in Computed Tomography (ACT) , 2019, DOI: 10.4236/act.2019.82002
Abstract: Purpose: To compare the diagnostic performance of estimated energy loss (EEL) calculated using a simplified Bernoulli formula at coronary computed tomography (CT) and single photon emission computed tomography (SPECT) to diagnose ischemia-causing stenosis by invasive fractional flow reserve (FFR). Methods: We retrospectively included 43 patients who underwent coronary CT, SPECT, and FFR measurement by catheter within 3 months. When an intermediate stenosis (40% - 70%) was present at CT, EEL was calculated using the following parameters: lesion length, diameter stenosis, minimal lumen area, and the myocardial volume. An EEL > 1.17 or diameter stenosis > 70% was determined ischemic. Stress-induced ischemia by SPECT was determined when a perfusion defect at stress was accompanied with a fill-in at rest. An FFR ≤ 0.80 or diameter stenosis >70 % was determined as ischemic by catheter. Results: A total of 26 vessels were determined as ischemic by catheter exam. The per-vessel sensitivity and specificity of EEL and SPECT were 81% vs 42% and 92% vs 91%, respectively. The accuracy of EEL to diagnose stenosis causing ischemia was significantly higher than SPECT (90% vs 81%, p = 0.04). The area under the curve of the receiver operating characteristics curve was also significantly higher for EEL than SPECT (0.86 vs 0.67, p < 0.005). Conclusions: EEL showed higher accuracy than SPECT to diagnose ischemia-causing stenosis by improving the sensitivity.
Development of Charging Infrastructure and Subsidies for Promoting Electric Vehicles  [PDF]
Kiyoshi Arakawa
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.811131
Abstract: This paper clarifies an effect of policy on the development of charging infrastructure and subsidies for promoting electric vehicles (EVs). Due to the long-term function of charging infrastructure, this paper constructs a multiple-period model to analyze policy effects on the diffusion of EVs from a long-term perspective. This paper shows that charging infrastructure and subsidy encourage innovation on increasing the battery capacity of EVs. Because intertemporal cost allocation can be executed in the development of a charging infrastructure with a subsidy, a policy with a long-term perspective can enhance the charging infrastructure and promote EVs effectively.
Clinical, Radiological, and Pathological Investigation of Asbestosis
Takumi Kishimoto,Katsuya Kato,Hiroaki Arakawa,Kazuto Ashizawa,Kouki Inai,Yukio Takeshima
International Journal of Environmental Research and Public Health , 2011, DOI: 10.3390/ijerph8030899
Abstract: By the radiological examination, differential diagnosis of asbestosis from chronic interstitial pneumonia such as IPF/UIP is difficult. The pathological features of asbestosis show the peribronchiolar fibrosis which suggest that asbestos fibers cause the inflammation of bronchioli. Therefore, the criteria for pathological diagnosis of asbestosis in 2010, contain the finding of peribronchiolar fibrosis again. Chest CT scanning including HRCT for total of 38 cases clinically diagnosed asbestosis were reviewed by 3 radiologists and one pulmonologist. On the other hand, the histology of lung tissues obtained by surgery or autopsy were examined by 4 pulmonological pathologists. Furthermore, the content of asbestos bodies in the lung was counted by phase-contrast microscopy. Thirteen cases were definitely diagnosed of asbestosis in the image including HRCT and 17 cases were diagnosed by the histopathological examination showing lung fibrosis with peribronchiolar fibrosis. Only 10 cases were indicated asbestosis by both the radiological and histopathological examinations. The mean value of asbestos bodies for these cases, was 2,133,255 per gram of dry lung tissue.
Effects of pectin liquid on gastroesophageal reflux disease in children with cerebral palsy
Reiko Miyazawa, Takeshi Tomomasa, Hiroaki Kaneko, Hirokazu Arakawa, Nobuzo Shimizu, Akihiro Morikawa
BMC Gastroenterology , 2008, DOI: 10.1186/1471-230x-8-11
Abstract: We enrolled 18 neurologically impaired children caused by cerebral palsy, with gastroesophageal reflux disease. In the first part of this study (pH monitoring), subjects were randomly allocated to two groups: fed with a high-pectin diet [enteral formula: pectin liquid = 2:1 (v/v)], or a low-pectin diet [enteral formula: pectin liquid = 3:1 (v/v)]. Two-channel esophageal pH monitoring was performed over 48 h. In the second part (clinical trial), subjects were fed a high- or low-pectin diet and non-pectin diet for 4 weeks in a crossover manner. Nurses recorded the feeding volume, number of episodes of vomiting, volume of gastric residue, episodes of cough and wheeze, frequency of using oxygen for dyspnea, and the day when the child could return to school. Cough and wheeze were recorded as a cough-score.The median value for the % time pH < 4 at the lower and upper esophagus was significantly decreased with a high-pectin diet [9.2% (6.2–22.6) vs. 5.0% (3.1–13.1); P < 0.01, 3.8% (2.9–11.2) vs. 1.6% (0.9–8.9); P < 0.01 (interquartile range), non-pectin and high-pectin, respectively]. The number of reflux episodes per day and duration of longest reflux were decreased significantly with a high-pectin, but not with a low-pectin diet. The median number of episodes of vomiting decreased significantly with a high-pectin diet [2.5/week (1.0–5.0) vs. 1.0 (1.0–1.5), P < 0.05]. The median cough-score was significantly decreased by both concentrations of pectin [8.5/week (1.0–11.5) vs. 2.0/week (0.0–3.0), fed with a high-pectin diet; 7.0/week (1.0–14.5) vs. 1.0/w (0.0–5.0), fed with a low-pectin diet, P < 0.05].Pectin liquid partially decreased gastroesophageal reflux as measured by eshophageal pH monitoring, and might improve vomiting and respiratory symptoms in children with cerebral palsy.ISRCTN19787793Gastroesophageal reflux (GER) appears to be a common, persistent, and severe disorder in children with neurologic impairment [1-3]. The estimated incidence of GER in patients with
Direct hemoperfusion with a polymyxin B-immobilized cartridge in intestinal warm ischemia reperfusion
Hiroaki Sato, Kiyohiro Oshima, Kazuhisa Arakawa, Katsumi Kobayashi, Hodaka Yamazaki, Yujin Suto, Izumi Takeyoshi
World Journal of Gastroenterology , 2008,
Abstract: AIM: To investigate the effectiveness of direct hemoperfusion with polymyxin B-immobilized fibers (DHP-PMX therapy) on warm ischemia-reperfusion (I/R) injury of the small intestine.METHODS: The proximal jejunum and distal ileum of mongrel dogs were resected. Warm ischemia was performed by clamping the superior mesenteric artery (SMA) and vein (SMV) for 2 h. Blood flow to the proximal small intestine was restored 1 h after reperfusion, and the distal small intestine was used as a stoma. The experiment was discontinued 6 h after reperfusion. The dogs were divided into two groups: the DHP-PMX group (n = 6, DHP-PMX was performed for 180 min; from 10 min prior to reperfusion to 170 min after reperfusion) and the control group (n = 5). The rate pressure product (RPP), SMA blood flow, mucosal tissue blood flow, and intramucosal pH (pHi) were compared between the two groups. The serum interleukin (IL)-10 levels measured 170 min after reperfusion were also compared.RESULTS: The RPP at 6 h after reperfusion was significantly higher in the PMX group than in the control group (12 174 ± 1832 mmHg/min vs 8929 ± 1797 mmHg/min, P < 0.05). The recovery rates of the SMA blood flow at 1 and 6 h after reperfusion were significantly better in the PMX group than in the control group (61% ± 7% vs 44% ± 4%, P < 0.05, and 59% ± 5% vs 35% ± 5%, P < 0.05, respectively). The recovery rate of the mucosal tissue blood flow and the pHi levels at 6 h after reperfusion were significantly higher in the PMX group (61% ± 8% vs 31% ± 3%, P < 0.05 and 7.91 ± 0.06 vs 7.69 ± 0.08, P < 0.05, respectively). In addition, the serum IL-10 levels just before DHP-PMX removal were significantly higher in the PMX group than in the control group (1 569 ± 253 pg/mL vs 211 ± 40 pg/mL, P < 0.05).CONCLUSION: DHP-PMX therapy reduced warm I/R injury of the small intestine. IL-10 may play a role in inhibiting I/R injury during DHP-PMX therapy.
Signature of Coherent Transport in Epitaxial Spinel-based Magnetic Tunnel Junctions Probed by Shot Noise Measurement
Takahiro Tanaka,Tomonori Arakawa,Kensaku Chida,Yoshitaka Nishihara,Daichi Chiba,Kensuke Kobayashi,Teruo Ono,Hiroaki Sukegawa,Shinya Kasai,Seiji Mitani
Physics , 2012, DOI: 10.1143/APEX.5.053003
Abstract: We measured the shot noise in fully epitaxial Fe/MgAl2OX/Fe-based magnetic tunneling junctions (MTJs). While the Fano factor to characterize the shot noise is very close to unity in the antiparallel configuration, it is reduced to 0.98 in the parallel configuration. This observation shows the sub-Poissonian process of electron tunneling in the parallel configuration, indicating the coherent tunneling through the spinel-based tunneling barrier of the MTJ.
A 7-Year-Old Boy with Light Cupula of the Horizontal Semicircular Canal  [PDF]
Hiroaki Ichijo
International Journal of Otolaryngology and Head & Neck Surgery (IJOHNS) , 2014, DOI: 10.4236/ijohns.2014.32018
Abstract:

Report of childhood positional vertigo is very rare. We present a 7-year-old boy who revealed persistent direction-changing geotropic positional nystagmus. In the supine position, horizontal nystagmus toward the left continued as long as the position was maintained. However, it ceased when the head was turned to the right side by 45°. With greater head turn (right-ear-down), nystagmus toward the right lasted for more than 1 minute. In the left-ear-down position, horizontal nystagmus toward the left occurred and lasted for more than 1 minute. After the disappearance of positional nystagmus, we detected canal paresis of the right ear by caloric test. We considered that the pathophysiology of the persistent type of geotropic nystagmus is a result of light debris cupulolithiasis of the horizontal canal.

Determination of Shear Center of Arbitrary Cross-Section  [PDF]
Hiroaki Katori
World Journal of Mechanics (WJM) , 2016, DOI: 10.4236/wjm.2016.68020
Abstract: In structural analysis, it is often necessary to determine the geometrical properties of cross section. The location of the shear center is greater importance for an arbitrary cross section. In this study, the problems of coupled shearing and torsional were analyzed by using the finite element method. Namely, the simultaneous equations with respect to the warping, shear deflection, angle of torsion and Lagrange’s multipliers are derived by finite element approximation. Solving them numerically, the matrix of the shearing rigidity and torsional rigidity is obtained. This matrix indicates the coupled shearing and torsional deflection. The shear center can be obtained determining the coordinate axes so as to eliminate the non-diagonal terms. Several numerical examples are performed and show that the present method gives excellent results for an arbitrary cross section.
Inverse Problems for an Euler-Bernoulli Beam: Identification of Bending Rigidity and External Loads  [PDF]
Hiroaki Katori
World Journal of Mechanics (WJM) , 2018, DOI: 10.4236/wjm.2018.85014
Abstract: We present a method for identifying the flexural rigidity and external loads acting on a beam using the finite-element method. We used mixed beam elements possessing transverse deflection and the bending moment as the primary degrees of freedom. The first step is to determine the bending moment from the transverse deflection and boundary conditions. The second step is to substitute the bending moment into the final equations with respect to the unknown parameters (flexural rigidity or external load). The final step solves the resulting system of equations. We apply this method to some inverse beam problems and provide an accurate estimation. Several numerical examples are performed and show that present method gives excellent results for identifying bending stiffness and distributed load of beam.
Vestibular Rehabilitation for the Patients with Intractable Vestibular Neuritis  [PDF]
Hiroaki Ichijo
International Journal of Otolaryngology and Head & Neck Surgery (IJOHNS) , 2018, DOI: 10.4236/ijohns.2018.76035
Abstract: Objective: To clarify whether vestibular rehabilitation is effective in improving spontaneous nystagmus in patients with intractable vestibular neuritis. Methods: The subjects were 8 patients (6 females and 2 males) with vestibular neuritis who revealed long-lasting (more than 2 months since the onset) horizontal spontaneous nystagmus toward the healthy side. We used thumbs-up head shaking for vestibular rehabilitation. This exercise involves active head shaking (1 Hz) while staring at one’s thumb nail. One set is 10 cycles. We asked the patient to do 3 sets (morning, afternoon, and night) every day. Results: The mean value of the slow-phase velocity of spontaneous nystagmus before treatment was 4.1°/s, and that 3 months after vestibular rehabilitation was 4.1°/s. No improvement was observed. Conclusion: Vestibular rehabilitation is not always effective in improving spontaneous nystagmus in patients with intractable vestibular neuritis. Therefore, clinicians should consider the possibility of long-term incomplete central compensation.
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