Modeling and Semi-Analytic Stability Analysis for Dynamics of AC Machines

In this article, a semi-analytical technique is proposed to predict stable sustained periodic responses of AC electrical machines. Based on such desired outputs, the proper selections of machine variables are captured, such as the perturbation parameter arisen from the relative movement between the stationary and rotating parts. Compared to the experimental results, the derived analytical results are relatively well-fitted with the studied practical cases.

P2620PIONEER-HF criteria ready for the prime time? Data from REDINSCOR II registry

Background New treatment strategies are needed to improve the prognosis in acute heart failure (AHF), recently PIONEER-HF results have been published showing in a selected group of patients a potential use of sacubitril/valsartan with safety in this scenario Purpose To evaluate the impact of PIONEER-HF potential indication in daily practice after AHF hospitalization at discharge Methods We included a subgroup of 909 patients consecutively admitted with AHF between October 2013 and December 2014 from a national multicentre, prospective registry with the complete data for this analysis. In the trial left ventricular ejection fraction (LVEF) ≤40% and natriuretic peptides at admission with values of NT-ProBNP≥1600 pg/ml were needed to be included. The clinical and analytic stability at discharge to safely start sacubitril/valsartan was considered as MDRD estimated Glomerular Filtration Rate≥30 mL/min/1.73 m2, Systolic Blood Pressure ≥100 mmHg and Potassium ≤5.2 mmol/L. Results The mean age was 72.1±12.01 years. Of these, 373 (38.8%) were female, 734 (76,6%) were hypertensive, 462 (48.2%) had diabetes and 282 (29.9%) coronary artery disease. At admission atrial fibrillation was found in 403 patients (40.1%) and 409 (45%) had reduced LVEF. The mean levels of NT-ProBNP 7259.4±9437.1 pg/ml. In this group of patients, the in-hospital mortality was 28 (2.9%) and the 1 year follow up mortality was 197 (20.5%) and the heart failure rehospitalizations in 1 year were 303 (31,5%). In table 1 the percentage of patients that fulfil the needed criteria for the application of PIONEER HF is shown. In our registry 235 patients (25.9%) could be potential users of sacubitril/valsartan after the acute phase of hospitalization Table 1 Elements to stablish indication Number of patients (%) NT-ProBNP ≥1600 pg/ml at admission 730 (80.3%) MDRD estimated GFR ≥30 mL/min/1.73 m2 at discharge 798 (87.8%) Systolic Blood Pressure ≥100 mmHg at discharge 755 (83.1%) Serum Potassium ≤5.2 mmol/L at discharge 856 (94.2%) Clinical and analytic stability at discharge 636 (70%) Left ventricular ejection fraction ≤40% 409 (45%) PIONEER HF Criteria 235 (25.9%) GFR: Glomerular Filtration Rate. Conclusions In our cohort of AHF patients around 1 out 4 could be treated with sacubitril/valsartan at discharge if we apply the PIONEER HF criteria in a contemporary setting, this finding could have potential implications in the prognosis and current costs of care in a population with high morbidity and mortality. Acknowledgement/Funding Heart Failure Program of the Red de Investigaciόn Cardiovascular del Instituto de Salud Carlos III, Madrid, Spain (RD12/0042) and FEDER

Quantification of Fecal Short Chain Fatty Acids by Liquid Chromatography Tandem Mass Spectrometry—Investigation of Pre-Analytic Stability

Short chain fatty acids (SCFAs) are generated by the degradation and fermentation of complex carbohydrates, (i.e., dietary fiber) by the gut microbiota relevant for microbe–host communication. Here, we present a method for the quantification of SCFAs in fecal samples by liquid chromatography tandem mass spectrometry (LC-MS/MS) upon derivatization to 3-nitrophenylhydrazones (3NPH). The method includes acetate, propionate, butyrate, and isobutyrate with a run time of 4 min. The reproducible (coefficients of variation (CV) below 10%) quantification of SCFAs in human fecal samples was achieved by the application of stable isotope labelled internal standards. The specificity was demonstrated by the introduction of a quantifier and qualifier ions. The method was applied to investigate the pre-analytic stability of SCFAs in human feces. Concentrations of SCFA may change substantially within hours; the degree and kinetics of these changes revealed huge differences between the donors. The fecal SCFA level could be preserved by the addition of organic solvents like isopropanol. An analysis of the colon content of mice either treated with antibiotics or fed with a diet containing a non-degradable and -fermentable fiber source showed decreased SCFA concentrations. In summary, this fast and reproducible method for the quantification of SCFA in fecal samples provides a valuable tool for both basic research and large-scale studies.

Asymptotic Stability Analysis of Binary Heterogeneous Traffic Based on Car-Following Model

We study the asymptotic stability of Chandler Model for a heterogeneous traffic by using numerical simulations. A simple binary platoon is considered which consists of two types of vehicles. Platoon stabilities under various kinds of combinations of parameters are investigated. It is found that the stability of the binary platoon cannot be determined by the mean values of individual vehicle’s parameters. Some combinations of parameters that benefit to the platoon stability are found. Several interesting properties of binary platoon’s stability are summarized. The analytic stability criterion of heterogeneous traffic reported in the historical literature is studied. The result indicates the analytic criterion is not rigorous, which is apt to overestimate the stability of heterogeneous platoon.