Thrust Measurement of a Multicycle Partially Filled Pulse Detonation Rocket Engine

In the present research, we experimentally verified the partial-fill effect in a multicycle pulse detonation rocketengine. The intermittent thrust of a pulse detonation rocket engine was measured by using a spring-dampermechanism that smoothed this intermittent thrust in the time direction. The intermittent mass flow rates wereassessed by gas cylinder pressure or mass difference measurement. The maximum specific impulse was 305 9 s atan ethylene and oxygen propellant fill fraction of 0:130 0:004. When the fill fraction was greater than 0.130, thespecific impulse was increased as the partial-fill fraction was decreased. When the fill fraction was less than 0.130, thespecific impulse was sharply decreased as the partial-fill fraction was decreased. This decrease was due to diffusionbetween propellant and purge gases and the short length of the transition from deflagration to detonation. Themulticycle pulse detonation rocket engine had a partial-fill effect that may have been mainly due to the suctioned airand was consistent with the single-cycle partial-fill model of Endo et al

Factors responsible for elevated plasma B-type natriuretic peptide levels in severe aortic stenosis: Comparison between elderly and younger patients

AbstractBackgroundElevated plasma B-type natriuretic peptide (BNP) is a predictor of outcome and helpful for risk stratification in aortic stenosis (AS). However, left ventricular (LV) diastolic dysfunction progresses with aging and may also influence plasma BNP levels in elderly patients. We hypothesized that plasma BNP levels may be influenced by age in severe AS, and that factors that affect the elevation of plasma BNP levels may be different between elderly and younger patients with AS.MethodsWe performed echocardiography in 341 patients with severe AS [aortic valve area (AVA)<1.0cm2] and classified them into two groups by age (elderly ≥75 years old, n=201; younger patients <75 years old, n=140). We used multivariate linear regression analysis to assess the factors that determine plasma BNP levels in both groups.ResultsAge was found to be one of the independent determinants of plasma BNP levels in all patients (β=0.135, p=0.005). Although AVA was similar in the two groups, plasma BNP levels and E/e′ were significantly higher in elderly than younger patients [133.0 (IQR, 73.3–329.7)pg/dl vs 92.8 (IQR, 40.6–171.8)pg/dl, p<0.01; 20±8 vs 16±6, p<0.01, respectively). In multivariate stepwise linear regression analysis, AVA index, LV ejection fraction, mass index, E/e′, estimated systolic pulmonary artery pressure (eSPAS), and the presence of atrial fibrillation were independent determinants of plasma BNP levels in younger patients. In contrast, the independent determinants of plasma BNP levels in elderly patients were LV ejection fraction, mass index, E/e′, eSPAS, the presence of atrial fibrillation, age, and hemoglobin levels, but not AVA index.ConclusionsThere may be differences in the factors that influence plasma BNP levels between elderly and younger patients with severe AS. In elderly patients, plasma BNP levels may be influenced more by these factors than AS severity compared with younger patients

Guideline from Japanese Society of Echocardiography : 2018 focused update incorporated into Guidance for the Management and Maintenance of Echocardiography Equipment

Echocardiography plays a pivotal role as an imaging modality in the modern cardiology practice. Information derived from echocardiography is definitely helpful for a patient care. The Japanese Society of Echocardiography has promoted echocardiography for a routine clinical and research use. One of the missions of the Society is to provide information that is useful for high-quality examinations. To ensure it, we believe equipment in good conditions and a comfortable environment are important for both a patient and an examiner. Thus, the Committee for Guideline Writing, the Japanese Society of Echocardiography published brief guidance for the routine use of echocardiography equipment in 2015. Recently, the importance of international standardization has been emphasized in the medical laboratories. Accordingly, the committee has revised and updated our guidance for the routine use of echocardiography equipment

Influence of Diabetes Mellitus on Left Ventricular Function in Patients Undergoing Coronary Artery Bypass Grafting

Objectives. Left ventricular function was assessed by two-dimensional echocardiography before and one year after coronary artery bypass grafting CABG in a series of patients with severe coronary artery disease with diabetes mellitus DM and without DM non-DM . Methods. Twenty-three patients with DM and 50 patients without DM, all with no previous myocardial infarction, underwent two-dimensional echocardiography before CABG and one year after CABG, in a non-matched study. For a matched study, 31 patients without DM who had almost the same left ventricular function as DM patients at the baseline were selected to and compare the rate of improvement in left ventricular function between the DM group and the matched non-DM group. Results. In the non-matched study, patient characteristics were not significantly different between the 2 groups except for the incidence of congestive heart failure within one year before CABG, which was significantly higher in the DM group. Fractional shortening was significantly lower in the DM group at the baseline p 0.05 and also one year after CABG p 0.0001 . Significant improvement in fractional shortening was seen in the non-DM group p 0.001 , but not in the DM group. The left ventricular enddiastolic diameter LVDd was significantly larger in the DM group at the baseline p 0.01 , and was still significantly larger in the DM group at one year after CABG p 0.01 . No improvement in LVDd was seen in the DM group. In the matched study, fractional shortening of the non-DM group also showed significant improvement after CABG p 0.001 . Moreover, the rate of improvement in fractional shortening was higher in the non-DM group than in the DM group p 0.05 . LVDd tended to be larger in the DM group p NS . Conclusions. Left ventricular dysfunction and left ventricular impaired improvement were seen in the patients with DM, and CABG improved left ventricular function in the patients without DM with poor left ventricular function. These findings indicate that CABG therapy may be inadequate for improving left ventricular function in patients with DM and severe left ventricular dysfunction at the baseline.

Impact of insulin resistance on subclinical left ventricular dysfunction in normal weight and overweight/obese japanese subjects in a general community

Background Insulin resistance carries increased risk of heart failure, although the pathophysiological mechanisms remain unclear. LV global longitudinal strain (LVGLS) assessed by speckle-tracking echocardiography has emerged as an important tool to detect early LV systolic abnormalities. This study aimed to investigate the association between insulin resistance and subclinical left ventricular (LV) dysfunction in a sample of the general population without overt cardiac disease. Methods We investigated 539 participants who voluntarily underwent extensive cardiovascular health check including laboratory test and speckle-tracking echocardiography. Glycemic profiles were categorized into 3 groups according to homeostatic model assessment of insulin resistance (HOMA-IR): absence of insulin resistance (HOMA-IR  − 16.65%). Results Forty-five (8.3%) participants had DM and 66 (12.2%) had abnormal HOMA-IR. LV mass index and E/e′ ratio did not differ between participants with and without abnormal HOMA-IR, whereas abnormal HOMA-IR group had significantly decreased LVGLS (− 17.6 ± 2.6% vs. − 19.7 ± 3.1%, p < 0.05). The prevalence of impaired LVGLS was higher in abnormal HOMA-IR group compared with normal HOMA-IR group (42.4% vs. 14.0%) and similar to that of DM (48.9%). In multivariable analyses, glycemic abnormalities were significantly associated with impaired LVGLS, independent of traditional cardiovascular risk factors and pertinent laboratory and echocardiographic parameters [adjusted odds ratio (OR) 2.38, p = 0.007 for abnormal HOMA-IR; adjusted OR 3.02, p = 0.003 for DM]. The independent association persisted even after adjustment for waist circumference as a marker of abdominal adiposity. Sub-group analyses stratified by body mass index showed significant association between abnormal HOMA-IR and impaired LVGLS in normal weight individuals (adjusted OR 4.59, p = 0.001), but not in overweight/obese individuals (adjusted OR 1.62, p = 0.300). Conclusions In the general population without overt cardiac disease, insulin resistance carries independent risk for subclinical LV dysfunction, especially in normal weight individuals