82 research outputs found
How does organizational restructuring contribute to HSR productivity growth?
Thesis (S.M. in Transportation)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 150-154).The institutional reform of Japan National Railway (JNR) in 1987 has been considered as a great success. After the Japanese railway reform, European countries introduced vertical separation management. However, the question whether the new companies' railway business has been improved by the privatization and vertical separation is still not well known. To evaluate the effect of the privatization and vertical separation, this thesis applied "productivity analysis". First, we set Tokaido Shinkansen and the Paris-Lyon line as our research object because that these lines introduced the latest technology when it had been constructed. This means the technological development which increases the productivity has been very limited. Second, these lines have been profitable railway lines for a long time. This thesis used multi-factor productivity (MFP). We set passenger-km and revenue as output separately, and personnel, non-personnel, and capital related expenses as input data. As a result, this thesis found that the JNR privatization has contributed to increase MFP of Tokaido Shinkansen after 1987. This thesis reviewed the previous research. As a result, we figured out that their research model has difficulties showing the effect of introducing the vertical separation. From the Swedish railway data, we judged even the small market competition has more relationship with increased productivity than the style of vertical separation. We believed that the future NEC HSR should introduce private sector's funds, and be operated by private sectors with competition within operators.by Ryusuke Sakamoto.S.M.in Transportatio
Productivity of Passenger Rail Transportation Services in the Northeast Corridor
Technological changes, capital investment, organizational reforms, and external factors can impact railway productivity. Using non-parametric single-factor and multifactor productivity (SFP and MFP) Törnqvist trans-log index approaches, we evaluated the performance of high-speed rail (HSR) lines in the U.S. during FY 2002-2012.
Intercity rail transportation in the NEC experienced considerable yet highly volatile productivity growth during FY 2002-2012, in the range of ~1-3% per year. Amtrak increased its ability to economically exploit the available capacity, but did not perform equally well on the supply side. The NEC became cumulatively 20% more productive on the demand side but only 3% on the supply side of productivity with respect to 2005 levels. Service changes, technical problems with trains, targeted capital investments, and economic recession and recovery were the main drivers of productivity change.
The main train services, the Acela Express and Northeast Regional, were very sensitive to external events, had large economies of scale, and implemented slow adjustment of capacity via rolling stock and infrastructure improvements, which varied depending on the service.
In the face of ongoing planning efforts, the NEC could consider the resurgence of demand and recent substantial productivity improvements to launch ambitious plans for HSR. Additional ideas of organization and coordination of rail could reveal hidden opportunities for future HSR development
Recurrence of angina pectoris after percutaneous coronary intervention is reduced by statins in Japanese patients
SummaryBackgroundStatins have been reported to reduce cardiovascular events in patients with coronary artery disease (CAD). Percutaneous coronary intervention (PCI) is commonly used to relieve ischemic symptoms in patients with CAD. However, there is little information on the effect of statins on cardiovascular events after PCI, even in the era of coronary stent implantation.MethodsA total of 1019 patients with acute or chronic CAD and modest total cholesterol levels (180–240mg/dl) were enrolled and randomly assigned to treatment with or without statins. We evaluated the effect of any available statin on the incidence of cardiovascular events after PCI. The primary endpoint was a composite of cardiovascular death, nonfatal acute myocardial infarction (MI), recurrent angina pectoris requiring emergency rehospitalization (rAP), heart failure, and stroke.ResultsIndications for PCI were stable angina in 54%, ST-elevation MI in 41% and non-ST-elevation MI/unstable angina pectoris in 5%. After 2 years of statin treatment, low-density lipoprotein cholesterol (LDL-C) decreased from 133 to 96mg/dl. Stents were implanted in 84% of all cases. The primary endpoint event rate was 9.5% in the statin group and 14.7% in the non-statin group (p=0.0292). Of all primary endpoint events, only rAP was significantly suppressed by statins (p=0.0027). In rAP patients, coronary angiography revealed that statins suppressed restenosis but not new lesions.ConclusionsFor Japanese CAD patients treated with PCI and stent implantation, statin therapy reduced the incidence of recurrent cardiovascular events, particularly rAP. Discretionary statin treatment to achieve LDL-C levels <100mg/dl effectively reduced restenosis causing rAP
磁歪材料を用いた3軸球面モータの特性評価
We propose a three-DOF spherical motor using magnetostrictive material (Galfenol). The motor consists of four U shape cores of Galfenol rods wound two coils, a permanent magnet, iron fixture, elastic ring and spherical rotor. Top of the rod is shaped step to exert torque. The magnetomotive force of the magnet provides bias magnetostriction for the rods and attractive force to maintain the rotor on the magnet. When opposite phase currents flow in coils of opposing rods, the torque for X or Y axes rotation is exerted on the rotor and the rotor is rotated based on smooth impact drive mechanism by saw tooth deformation of the rod, slowly expansion (contraction) and rapidly contraction (expansion) of the rods. On the other hand, when opposite phase currents flow in two coils of four rods, torque for Z axis rotation is exerted on the rotor by bending deformation of four rods. In this paper, the displacements of rods with sinusoidal and sawtooth currents resulting in angular velocity of the rotor were investigated to verify the principle.Special Issue the 23rd Symposium on Electromagnetics and Dynamic
Uric acid-lowering and renoprotective effects of topiroxostat, a selective xanthine oxidoreductase inhibitor, in patients with diabetic nephropathy and hyperuricemia: a randomized, double-blind, placebo-controlled, parallel-group study (UPWARD study)
金沢大学医薬保健研究域医学系Background: Hyperuricemia is supposed to be an independent risk factor for kidney dysfunction in diabetic patients. We attempted to examine the uric acid-lowering effect and the renoprotective effect of topiroxostat, a selective xanthine oxidoreductase inhibitor, in patients with diabetic nephropathy and hyperuricemia in this pilot study. Methods: The study design was randomized, double-blind, placebo-controlled, parallel-group study. A total of 65 patients with hyperuricemia and diabetic nephropathy with microalbuminuria were enrolled and assigned to either the topiroxostat group or the placebo group. Topiroxostat (stepwise dosing from 40 to 160 mg/day) or matching placebo was administered BID for 28 weeks. The primary endpoint was a change in the urinary albumin-to-creatinine ratio in the first-morning-void urine sample. Secondary endpoints were changes in the estimated glomerular filtration rate and the serum uric acid level. Results: At 28 weeks, there was no significant difference in the percent change from baseline in the urinary albumin-to-creatinine ratio between the two groups (topiroxostat: 0 vs. placebo: 17%, p = 0.3206), but the changes in the estimated glomerular filtration rate (− 0.2 vs. − 4.0 mL/min/1.73 m2, p = 0.0303) and the serum uric acid level (− 2.94 vs. − 0.20 mg/dL, p < 0.0001) were significantly different between the topiroxostat and placebo groups. Gouty arthritis occurred in 1 patient in the placebo group and no patients in the topiroxostat group. Conclusion: These findings support that diabetic nephropathy combined with hyperuricemia may be associated with kidney dysfunctions. Topiroxostat provides strict control of the serum uric acid level preventing decline of eGFR in these patients. © 2018 The Author(s)Embargo Period 12 month
Plaque REgression with Cholesterol absorption Inhibitor or Synthesis inhibitor Evaluated by IntraVascular UltraSound (PRECISE-IVUS Trial): Study protocol for a randomized controlled trial
AbstractBackgroundAlthough the positive association between achieved low-density lipoprotein cholesterol (LDL-C) level and the risk of coronary artery disease (CAD) has been confirmed by randomized studies with statins, many patients remain at high residual risk of events suggesting the necessity of novel pharmacologic strategies. The combination of ezetimibe/statin produces greater reductions in LDL-C compared to statin monotherapy.PurposeThe Plaque REgression with Cholesterol absorption Inhibitor or Synthesis inhibitor Evaluated by IntraVascular UltraSound (PRECISE-IVUS) trial was aimed at evaluating the effects of ezetimibe addition to atorvastatin, compared with atorvastatin monotherapy, on coronary plaque regression and change in lipid profile in patients with CAD.MethodsThe study is a prospective, randomized, controlled, multicenter study. The eligible patients undergoing IVUS-guided percutaneous coronary intervention will be randomly assigned to receive either atorvastatin alone or atorvastatin plus ezetimibe (10mg) daily using a web-based randomization software. The dosage of atorvastatin will be increased by titration within the usual dose range with a treatment goal of lowering LDL-C below 70mg/dL based on consecutive measures of LDL-C at follow-up visits. IVUS will be performed at baseline and 9–12 months follow-up time point at participating cardiovascular centers. The primary endpoint will be the nominal change in percent coronary atheroma volume measured by volumetric IVUS analysis.ConclusionPRECISE-IVUS will assess whether the efficacy of combination of ezetimibe/atorvastatin is noninferior to atorvastatin monotherapy for coronary plaque reduction, and will translate into increased clinical benefit of dual lipid-lowering strategy in a Japanese population
Impact of Dual Lipid-Lowering Strategy With Ezetimibe and Atorvastatin on Coronary Plaque Regression in Patients With Percutaneous Coronary Intervention The Multicenter Randomized Controlled PRECISE-IVUS Trial
AbstractBackgroundDespite standard statin therapy, a majority of patients retain a high “residual risk” of cardiovascular events.ObjectivesThe aim of this study was to evaluate the effects of ezetimibe plus atorvastatin versus atorvastatin monotherapy on the lipid profile and coronary atherosclerosis in Japanese patients who underwent percutaneous coronary intervention (PCI).MethodsThis trial was a prospective, randomized, controlled, multicenter study. Eligible patients who underwent PCI were randomly assigned to atorvastatin alone or atorvastatin plus ezetimibe (10 mg) daily. Atorvastatin was uptitrated with a treatment goal of low-density lipoprotein cholesterol (LDL-C) <70 mg/dl. Serial volumetric intravascular ultrasound was performed at baseline and again at 9 to 12 months to quantify the coronary plaque response in 202 patients.ResultsThe combination of atorvastatin/ezetimibe resulted in lower levels of LDL-C than atorvastatin monotherapy (63.2 ± 16.3 mg/dl vs. 73.3 ± 20.3 mg/dl; p < 0.001). For the absolute change in percent atheroma volume (PAV), the mean difference between the 2 groups (–1.538%; 95% confidence interval [CI]: –3.079% to 0.003%) did not exceed the pre-defined noninferiority margin of 3%, but the absolute change in PAV did show superiority for the dual lipid-lowering strategy (–1.4%; 95% CI: –3.4% to –0.1% vs. –0.3%; 95% CI: –1.9% to 0.9% with atorvastatin alone; p = 0.001). For PAV, a significantly greater percentage of patients who received atorvastatin/ezetimibe showed coronary plaque regression (78% vs. 58%; p = 0.004). Both strategies had acceptable side effect profiles, with a low incidence of laboratory abnormalities and cardiovascular events.ConclusionsCompared with standard statin monotherapy, the combination of statin plus ezetimibe showed greater coronary plaque regression, which might be attributed to cholesterol absorption inhibition–induced aggressive lipid lowering. (Plaque Regression With Cholesterol Absorption Inhibitor or Synthesis Inhibitor Evaluated by Intravascular Ultrasound [PRECISE-IVUS]; NCT01043380
Percutaneous coronary intervention using new-generation drug-eluting stents versus coronary arterial bypass grafting in stable patients with multi-vessel coronary artery disease: From the CREDO-Kyoto PCI/CABG registry Cohort-3
AIMS: There is a scarcity of studies comparing percutaneous coronary intervention (PCI) using new-generation drug-eluting stents (DES) with coronary artery bypass grafting (CABG) in patients with multi-vessel coronary artery disease. METHODS AND RESULTS: The CREDO-Kyoto PCI/CABG registry Cohort-3 enrolled 14927 consecutive patients who underwent first coronary revascularization with PCI or isolated CABG between January 2011 and December 2013. The current study population consisted of 2464 patients who underwent multi-vessel coronary revascularization including revascularization of left anterior descending coronary artery (LAD) either with PCI using new-generation DES (N = 1565), or with CABG (N = 899). Patients in the PCI group were older and more often had severe frailty, but had less complex coronary anatomy, and less complete revascularization than those in the CABG group. Cumulative 5-year incidence of a composite of all-cause death, myocardial infarction or stroke was not significantly different between the 2 groups (25.0% versus 21.5%, P = 0.15). However, after adjusting confounders, the excess risk of PCI relative to CABG turned to be significant for the composite endpoint (HR 1.27, 95%CI 1.04-1.55, P = 0.02). PCI as compared with CABG was associated with comparable adjusted risk for all-cause death (HR 1.22, 95%CI 0.96-1.55, P = 0.11), and stroke (HR 1.17, 95%CI 0.79-1.73, P = 0.44), but with excess adjusted risk for myocardial infarction (HR 1.58, 95%CI 1.05-2.39, P = 0.03), and any coronary revascularization (HR 2.66, 95%CI 2.06-3.43, P<0.0001). CONCLUSIONS: In this observational study, PCI with new-generation DES as compared with CABG was associated with excess long-term risk for major cardiovascular events in patients who underwent multi-vessel coronary revascularization including LAD
The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force
「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection
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