6 research outputs found

    Optimal Design Methodology Emphasizing Surface Equipment Placement Applied to 6U CubeSats

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    In recent years, the number of launches of nano-satellites, which have the advantage of being developed in a short period of time, has increased rapidly. However, several issues need to be addressed to maximize the benefits of nano-satellites. One of them is that theoretical methods have not been widely applied to the placement of equipment on satellites. Therefore, this paper proposes an Optimal Design Methodology Emphasizing Surface Equipment Placement Applied to 6U CubeSats . It details the design and development of two 6U CubeSats using this method, along with the results and lessons learned

    Left Ventricular End-Systolic Volume Is a Reliable Predictor of New-Onset Heart Failure with Preserved Left Ventricular Ejection Fraction

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    Background. Left ventricular (LV) ejection fraction (EF) and LV volumes were reported to have prognostic efficacy in cardiac diseases. In particular, the end-systolic volume index (LVESVI) has been featured as the most reliable prognostic indicator. However, such efficacy in patients with LVEF ≥ 50% has not been elucidated. Methods. We screened the patients who received cardiac catheterization to evaluate coronary artery disease concomitantly with both left ventriculography and LV pressure recording using a catheter-tipped micromanometer and finally enrolled 355 patients with LVEF ≥ 50% and no history of heart failure (HF) after exclusion of the patients with severe coronary artery stenosis requiring early revascularization. Cardiovascular death or hospitalization for HF was defined as adverse events. The prognostic value of LVESVI was investigated using a Cox proportional hazards model. Results. A univariable analysis demonstrated that age, log BNP level, tau, peak − dP/dt, LVEF, LV end-diastolic volume index (LVEDVI), and LVESVI were associated with adverse events. A correlation analysis revealed that LVESVI was significantly associated with log BNP level (r = 0.356, p<0.001), +dP/dt (r = −0.324, p<0.001), −dP/dt (r = 0.391, p<0.001), and tau (r = 0.337, p<0.001). Multivariable analysis with a stepwise procedure using the variables with statistical significance in the univariable analysis revealed that aging, an increase in BNP level, and enlargement of LVESVI were significant prognostic indicators (age: HR: 1.071, 95% CI: 1.009–1.137, p=0.024; log BNP : HR : 1.533, 95% CI: 1.090–2.156, p=0.014; LVESVI : HR : 1.051, 95% CI: 1.011–1.093, p=0.013, respectively). According to the receiver-operating characteristic curve analysis for adverse events, log BNP level of 3.23 pg/ml (BNP level: 25.3 pg/ml) and an LVESVI of 24.1 ml/m2 were optimal cutoff values (BNP : AUC : 0.753, p<0.001, LVESVI : AUC : 0.729, p<0.001, respectively). Conclusion. In patients with LVEF ≥ 50%, an increased LVESVI is related to the adverse events. LV contractile performance even in the range of preserved LVEF should be considered as a role of a prognostic indicator

    Late in-stent restenosis after sirolimus-eluting stent implantation is related to thrombus formation—Insight from a case with IVUS, OCT, and histological findings

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    SummaryWe experienced a case of very late in-stent restenosis of a sirolimus-eluting stent (SES) (3.0mm×18mm) in the left anterior descending coronary artery in a 62-year-old man with type 2 diabetes mellitus, dyslipidemia, and hypertension. Angina pectoris recurred 39 months after the index percutaneous coronary intervention (PCI). We performed PCI with optical coherence tomography (OCT) and intravascular ultrasound (IVUS) guidance. OCT showed very eccentric low signal plaque with a high signal thin cap on the delayed healing stent struts without intimal coverage. IVUS showed that the plaque was eccentric and hypoechogenic with a “black hole appearance.” We used a filter wire (Filtrap™, Nipro, Osaka, Japan) to prevent distal embolism. Filter no-reflow occurred after predilatation. We deployed a paclitaxel-eluting stent followed by postdilatation. After aspiration and Filtrap™ withdrawal, thrombolysis in myocardial infarction 3 flow was obtained. Histopathological analysis revealed that the main tissue was composed of fibrin deposits with scarce inflammatory cells and proteoglycans. This case revealed that fibrin formation is related to very late in-stent restenosis and OCT and IVUS characteristics of this case are shown
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