387 research outputs found

    Right vs. left ventricular longitudinal strain for mortality prediction after transcatheter aortic valve implantation

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    INTRODUCTION This study aims at exploring biventricular remodelling and its implications for outcome in a representative patient cohort with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI). METHODS AND RESULTS Pre-interventional echocardiographic examinations of 100 patients with severe AS undergoing TAVI were assessed by speckle tracking echocardiography of both ventricles. Association with mortality was determined for right ventricular global longitudinal strain (RVGLS), RV free wall strain (RVFWS) and left ventricular global longitudinal strain (LVGLS). During a median follow-up of 1,367 [959-2,123] days, 33 patients (33%) died. RVGLS was lower in non-survivors [-13.9% (-16.4 to -12.9)] than survivors [-17.1% (-20.2 to -15.2); P = 0.001]. In contrast, LVGLS as well as the conventional parameters LV ejection fraction (LVEF) and RV fractional area change (RVFAC) did not differ (P = ns). Kaplan-Meier analyses indicated a reduced survival probability when RVGLS was below the -14.6% cutpoint (P < 0.001). Lower RVGLS was associated with higher mortality [HR 1.13 (95% CI 1.04-1.23); P = 0.003] independent of LVGLS, LVEF, RVFAC, and EuroSCORE II. Addition of RVGLS clearly improved the fitness of bivariable and multivariable models including LVGLS, LVEF, RVFAC, and EuroSCORE II with potential incremental value for mortality prediction. In contrast, LVGLS, LVEF, and RVFAC were not associated with mortality. DISCUSSION In patients with severe AS undergoing TAVI, RVGLS but not LVGLS was reduced in non-survivors compared to survivors, differentiated non-survivors from survivors, was independently associated with mortality, and exhibited potential incremental value for outcome prediction. RVGLS appears to be more suitable than LVGLS for risk stratification in AS and timely valve replacement

    An educational initiative for Mexican school-aged children to promote the consumption of fruit, vegetables and physical activity

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    Aim:&nbsp;To present the results of a community initiative focused on strengthening physical activity and the consumption of fruits, vegetables and natural water while discouraging the use of highly energetic food and sugary drinks in public schools of Morelos. Methods:&nbsp;A quasi-experimental study with an educational initiative focused on the school community of two primary schools and two junior high schools. Pre- and-post initiative measurements were made. The study took place in the municipality of Yautepec, Morelos, Mexico, in a rural area and an urban area, from August 2010 to July 2011.&nbsp;&nbsp; Results:&nbsp;Water consumption among school-aged children increased from 15.1% to 20.1% and soda consumption decreased from 21.4% to 13.2%. A slight increase in the consumption of fruits and vegetables was also measured (oranges, jicamas, bananas, tomatoes, prickly pear pads, lettuces), that are accessible in the region. It was found that the supply of fresh food is limited and that high energy density foods have an oversupply in both study areas. Physical activity increased with actions such as football and dancing, in accordance with the baseline measurement. No changes were observed in the nutritional condition of school-aged children (n=150; 13.3% with overweight and 7.3% with emaciation), or in adults who presented a body mass index higher than normal, 60.2% to 88.4%. Conclusion:&nbsp;In addition to educational activities, schools need to implement strategies to improve the access and availability of fresh foods while limiting the access of high energy-density foods. &nbsp; &nbsp

    Right heart strain in arrhythmogenic right ventricular cardiomyopathy: implications for cardiovascular outcome

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    AIMS Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by progressive myocardial dysfunction and associated with an increased risk of major cardiovascular (CV) events. To determine right heart strain (ventricular and atrial global longitudinal strain (RVGLS and RAGLS) in patients with definite ARVC and its association with adverse events during follow-up. METHODS AND RESULTS RVGLS and RAGLS were analysed in focused right heart apical views from 70 patients using TomTec ImageArena and association with a composite endpoint was determined (sustained ventricular arrhythmia and cardiovascular death). Over a median follow-up duration of 4.9 years, 26 (37%) patients met the endpoint. RVGLS was significantly impaired in the event group (-11.5 [-13.3 to -10.2] %) vs. the no-event group (-15.8 [-17.1 to -14.5] %, P < 0.001), and so was RAGLS (22.8 [21.4-27.4] % vs. 31.5 [25.1-39.6] %, respectively, P < 0.001). In Cox regression, RVGLS (HR 1.36, P < 0.001) and RAGLS (HR 0.92, P = 0.002) were associated with a higher risk of adverse events. In multivariable Cox regression models, RVGLS and RAGLS remained independent of and were incremental to age, gender, and conventional RV parameters, and model fitness was improved when RVGLS and RAGLS were applied together rather than alone. CONCLUSION RVGLS and RAGLS are more impaired in patients with adverse events and associated with adverse events independent of age, gender, and conventional RV parameters. When RVGLS and RAGLS are applied together, prediction models are improved suggesting that right heart strain may form part of the echocardiographic routine protocol in patients with ARVC

    Relationship between quantum decoherence times and solvation dynamics in condensed phase chemical systems

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    A relationship between the time scales of quantum coherence loss and short-time solvent response for a solute/bath system is derived for a Gaussian wave packet approximation for the bath. Decoherence and solvent response times are shown to be directly proportional to each other, with the proportionality coefficient given by the ratio of the thermal energy fluctuations to the fluctuations in the system-bath coupling. The relationship allows the prediction of decoherence times for condensed phase chemical systems from well developed experimental methods.Comment: 10 pages, no figures, late

    Super-resolution imaging reveals resistance to mass transfer in functionalized stationary phases

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    Chemical separations are costly in terms of energy, time, and money. Separation methods are optimized with inefficient trial-and-error approaches that lack insight into the molecular dynamics that lead to the success or failure of a separation and, hence, ways to improve the process. We perform super-resolution imaging of fluorescent analytes in four different commercial liquid chromatography materials. Surprisingly, we observe that chemical functionalization can block over fifty percent of the porous interior of the material, rendering it inaccessible to small molecule analytes. Only in situ imaging unveils the inaccessibility when compared to the industry-accepted ex situ characterization methods. Selectively removing some of the functionalization with solvent restores pore access without significantly altering the single-molecule kinetics that underlie the separation and agree with bulk chromatography measurements. Our molecular results determine that commercial stationary phases, marketed as fully porous, are over-functionalized and provide a new avenue to characterize and direct separation material design from the bottom-up

    Left ventricular global work index and prediction of cardiovascular mortality after transcatheter aortic valve implantation

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    INTRODUCTION Echocardiography is used for assessment of patients after transcatheter aortic valve implantation (TAVI). Global work index (GWI) integrates LV deformation throughout the cardiac cycle and LV afterload and may be advantageous for long-term follow-up. METHODS We analysed 144 patients with severe aortic stenosis who underwent TAVI and echocardiography within two weeks afterwards. GE EchoPAC v2.6 was applied for determining LV ejection fraction, global longitudinal strain (GLS), stroke work (SW), cardiac power output (CPO), and GWI. The endpoint was cardiovascular mortality. RESULTS During median follow-up of 625 [IQR: 511-770] days, 20 (14%) patients died. Clinical baseline characteristics were comparable between non-survivors and survivors. GWI (p = 0.003) and LVEF (p = 0.039) were lower in non-survivors, while GLS, SW, and CPO were not different. In Kaplan-Meier analysis patients with GWI ≤1234 mmHg% exhibited a lower survival probability (P = 0.006). In univariable Cox regression, a significant mortality association was identified for GWI (P = 0.004), weaker for LVEF (P = 0.014), but not for the other parameters. In multivariable Cox regression, GWI independently improved an LV systolic function model including LVEF and GLS. Similarly, GWI but not LVEF independently improved outcome association of different clinical models. CONCLUSIONS GWI was lower in non-survivors than survivors, differentiated non-survivors from survivors, was associated with mortality independent of clinical or LV parameters, and improved the fitness of clinical or LV prediction models. In contrast, GLS, SW, and CPO did not show any of these properties. GWI provides added value for follow-up after TAVI possibly by integrating LV deformation throughout the cardiac cycle

    Right vs. left ventricular longitudinal strain for mortality prediction after transcatheter aortic valve implantation

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    IntroductionThis study aims at exploring biventricular remodelling and its implications for outcome in a representative patient cohort with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI).Methods and resultsPre-interventional echocardiographic examinations of 100 patients with severe AS undergoing TAVI were assessed by speckle tracking echocardiography of both ventricles. Association with mortality was determined for right ventricular global longitudinal strain (RVGLS), RV free wall strain (RVFWS) and left ventricular global longitudinal strain (LVGLS). During a median follow-up of 1,367 [959–2,123] days, 33 patients (33%) died. RVGLS was lower in non-survivors [−13.9% (−16.4 to −12.9)] than survivors [−17.1% (−20.2 to −15.2); P = 0.001]. In contrast, LVGLS as well as the conventional parameters LV ejection fraction (LVEF) and RV fractional area change (RVFAC) did not differ (P = ns). Kaplan–Meier analyses indicated a reduced survival probability when RVGLS was below the −14.6% cutpoint (P &lt; 0.001). Lower RVGLS was associated with higher mortality [HR 1.13 (95% CI 1.04–1.23); P = 0.003] independent of LVGLS, LVEF, RVFAC, and EuroSCORE II. Addition of RVGLS clearly improved the fitness of bivariable and multivariable models including LVGLS, LVEF, RVFAC, and EuroSCORE II with potential incremental value for mortality prediction. In contrast, LVGLS, LVEF, and RVFAC were not associated with mortality.DiscussionIn patients with severe AS undergoing TAVI, RVGLS but not LVGLS was reduced in non-survivors compared to survivors, differentiated non-survivors from survivors, was independently associated with mortality, and exhibited potential incremental value for outcome prediction. RVGLS appears to be more suitable than LVGLS for risk stratification in AS and timely valve replacement

    Evaluación del efecto de la velocidad de agitación sobre la remoción de cromo hexavalente a escala piloto

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    Este trabajo experimental se desarrolla en un reactor piloto de laboratorio del 9 L utilizando electrodos estáticos de acero al carbón. Se obtuvo el consumo de potencia, el tiempo de mezclado y la cinética de reducción del Cr(VI) para diferentes velocidades de agitación. Para este trabajo se utilizaron números adimensionales para poder escalar el sistema. De forma experimental, se encontró que a velocidades de agitación mayores de 300 rpm se obtiene un buen mezclado, sin embargo al aumentar a 500 rpm se observa que por cada g de Cr(VI) se requiere menor consumo de energía que en todos los casos.This experimental work was carried out in a laboratory pilot reactor of 19 L using carbon steel static electrodes. Power consumed, mixing time and Cr(VI) reduction kinetic at different agitation speeds were obtained. Dimensionless numbers were used to scale up the system. Experimentally, it was found that at speed of agitation greater than 300 rpm there is good mixing in the reactor, but the power consumed for each g of Cr (VI) was the lowest at 500 rpm
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