Impact of transcatheter aortic valve implantation on the left ventricular mass

Background: Aortic stenosis (AS) induces pressure overload of the left ventricle (LV) and results in left ventricular hypertrophy. The remodeling of the LV in patients with AS is a com­plex process including structural and functional disturbances. After aortic valve replacement, reverse remodeling of LV begins. The aim of this study was to evaluate the impact of transcatheter aortic valve ımplantation (TAVI) on LV mass (LVM) in early and mid-term follow-ups after the procedure. Methods and Results: We enrolled consecutive 75 patients who underwent successful TAVI. Transthoracic echocardiography was performed prior to TAVI and at hospital discharge, in the 1st month and 6th month of the follow-ups. The mean LV ejection fraction improved significantly after TAVI (54.2 ± 15.0% to 57.3 ± 11.7%, p < 0.001). There were no significant changes between the baseline and discharge mean LVM and LVM index values (LVMI; p = 0.1). However, LVMI decreased significantly in the 1st month of follow-up compared to baseline (123.3 ± 20.3 to 127.9 ± 21.3 g/m2, respectively, p < 0.001). Also, significant regression of LVM was observed at the 1st month of follow-up compared to baseline (228.3 ± 33.5 g vs. 236.5 ± 34.2 g, respectively, p < 0.001). Furthermore, the significant regression in both of LVM and LVMI continued at 1st and 6th months of the follow-ups (p < 0.001). Conclusions: A significant regression of LVM was observed after TAVI. These changes may have prognostic value in patients with severe AS

Immediate recovery of the left atrial and left ventricular diastolic function after transcatheter aortic valve implantation: A transesophageal echocardiography study

Background: Chronic increased afterload due to severe aortic stenosis (AS) results in com­pensatory concentric left ventricular (LV) hypertrophy and LV dysfunction. These in turn cause remodeling of the left heart. The aim of this study was to investigate the acute effect of transcatheter aortic valve implantation (TAVI) on left atrial (LA) mechanics and LV diastolic function. Methods: The study consisted of a total of 35 consecutive patients (mean age was 77.7 ± 5.0 years, 25 female) undergoing TAVI. All TAVI procedures have been performed under the transesophageal echocardiography (TEE) guidance. Before and 24 h after TAVI, all patients underwent transthoracic echocardiography (TTE) and mitral inflow velocities with pulsed-wave (PW) Doppler including early filling wave (E), late diastolic filling wave (A), and E/A ratio were obtained. LV diastolic function was also explored by pulsed tissue Doppler imaging (TDI). Early (E’) and late (A’) diastolic annular velocities, E’/A’ ratio and E/E’ ratio were obtained. In addition, during the procedure before and minutes after the valve implantation, the left atrial appendage-peak antegrade flow velocity (LAA-PAFV) was measured and recorded with TEE. Results: Compared with baseline, the mean mitral E, septal E’ and E’/A’ ratio increased significantly after TAVI. In addition, the LAA-PAFV increased significantly within minutes of TAVI (32.45 ± 10.7 cm/s vs. 47.6 ± 12.6 cm/s, p < 0.001). Conclusions: TAVI improves LV diastolic function and LA performance immediately

Impact of transcatheter aortic valve implantation in patients with reduced ejection fraction

Background: Aortic stenosis increases with age. According to guidelines, left ventricular systolic dysfunction is an indication for aortic valve replacement, even in asymptomatic patients. There is no clear data on the application of transcatheter aortic valve implantation (TAVI), which is a method showing continuous improvement in recent years, in patients with reduced ejection fraction (REF) having a poor prognosis for surgical aortic valve replacement. We therefore aimed to investigate the effect of TAVI on left ventricular ejection fraction (LVEF) and also its efficacy and safety in patients with REF. Methods and results: The study included 104 patients who underwent transfemoral TAVI in our clinic. The patients were divided into two groups: LVEF ≤ 45% (REF group, n = 28) and LVEF > 45% (preserved ejection fraction [PEF] group, n = 76). Follow-up measure­ments were performed at baseline, discharge, 1st, 6th and 12th months. No statistical difference was found between the groups with respect to complications and mortality rates. A statistically significant difference was detected in LVEF after TAVI, either in all patients (53.9 ± 14.6, 57.0 ± 11.4, 59.4 ± 8.4, 60.4 ± 6.8, 63.2 ± 3.9, respectively, at baseline, discharge, 1st, 6th and 12th months, p < 0.001) or in the groups separately. A statistically significant increase in LVEF (p < 0.001) was determined at discharge, 1st, 6th and 12th months, whereas LVEF increased in all follow-ups of the PEF group, however this elevation reached a statistical significance only at the 1st month (p = 0.04). Conclusions: Our study has shown the positive effect of TAVI on LVEF and its effective and safe applicability in patients with REF.

Investigation of Pre-Service Science Teachers' Self- Worth Beliefs in terms of Some Variables

Bu çalışmanın amacı, fen bilgisi öğretmen adayları (FBÖA)'nın sahip oldukları öz-değer inançlarını alt alanları ile incelemek ve bazı değişkenlerin FBÖA'nın öz-değer inançlarına etkisini araştırmaktır. Çalışmaya Türkiye'de orta ölçekli bir üniversitede eğitim alan toplam 250 FBÖA katılmıştır. Veriler 'Öz-Değer İnanç Anketi' (Crocker, Luhtanen, Cooper ve Bouvrette, 2003) ile toplanmıştır. Anketin Türkçe uyarlaması Çetin, Akın ve Eroğlu (2011) tarafından yapılmıştır. Veri analizinde betimsel analiz, iki yönlü MANOVA analizi ve çoklu regresyon analizi kullanılmıştır. Çalışmadan elde edilen bulgulara göre, FBÖA'nın temel yaşam alanlarındaki memnuniyetleri ve öz-değer inançları yüksek çıkmıştır. Ayrıca cinsiyet ve okul ortalamalarının öz-değer inançlarına ait alt alanlara etkisinin olduğu görülürken, temel yaşam alanlardaki memnuniyetleri gösteren değişkenlerin öz-değer inançları üzerinde herhangi bir etkisinin olmadığı sonucuna ulaşılmıştırThe purpose of this study was to investigate pre-service science teachers' (PSTs) selfworth beliefs with sub-domains and effects of some variables on these beliefs. A total of 250 PSTs attending to faculty of education in a mid-sized university in Turkey were involved in the study. Data were collected through 'Self-Worth Scale' (Crocker, Luhtanen, Cooper & Bouvrette, 2003). It was adapted into Turkish by çetin, Akın and Eroğlu (2011). Three kinds of statistical analysis were used: Descriptive statistics, two way MANOVA and multiple regression analysis. The findings revealed that PSTs' satisfaction in the life and their self-worth beliefs were high. Additionally, effects of PSTs' gender and grade point averages were found on sub-domains of self-worth beliefs significantly, while variables indicating satisfaction in the life have no effects on selfworth belief

Estimation of residential electricity demand in Hong Kong under electricity charge subsidies

International audienceOver the past decade, the Hong Kong (HK) government provided electricity charges subsidies for residential accounts to alleviate the burden of inflation and, later, the burden of economic downturn. In this study, we estimate an econometric model of residential electricity demand and test the existence of a stable long-run relationship for the period 1980–2016, while accounting for the relief measures set out by the HK government since 2008. Empirical results suggest that there exists a long-run relationship among residential electricity consumption, electricity price, income per capita, and weather variables (temperature or cooling degree days). In the absence of electricity charge subsidies, the demand is found to be both price and income inelastic. On the other hand, HK's residential electricity consumers are unresponsive to price and income changes when electricity subsidies are in place. Following its new carbon reduction plan, HK is gradually phasing out coal for electricity generation to replace it mainly with natural gas. Our results suggest that new residential electricity charge subsidies can lessen the effectiveness of6 climate policies aimed at reducing electricity consumption through increases in the electricity price

An experimental investigation into heat transfer in milk cooling vessels

The raw milk is an important basic material for many food products. Fresh milk must be cooled immediately after milking to keep high quality and processability. In this work, the overall heat transfer coefficients of the milk cooling vessels used for this purpose have been studied experimentally. This study is aimed at determining the overall heat transfer coefficients of cooling vessels, which have different types and capacities without freezing and churning to avoid separation of milk's fat. Vessels are used ranged as follows: 300-500-1000-1500-1850-2000 liters for verticals and 2000-2500-3000-4000-5000-6000 liters for horizontals. It is found that the theoretical calculations are in satisfactory agreement with the experimental data. As a result of investigation, the overall heat transfer coefficient can be written in relation to power intensity for horizontal vessels. It is a certain constant value for vertical ones. (c) 2018 Sharif University of Technology. All rights reserved

The Effect of Educational Intervention Based on Chronic Care Model on the Management of Hypertension

Objective: This study was conducted to examine the effect of planned educational intervention based on the chronic care model on the management of patients with hypertension. The chronic care model is a framework for organizing and improving chronic illness care, based on a proactive, planned approach that incorporates patient self-care, provider, and system-level interventions. Several instruments have been developed to evaluate the effects of chronic care model implementation on care and treatment outcomes. The Patient Assessment of Chronic Illness Care questionnaire is used in the instrument to evaluate the delivery of care for patients. Methods: The study was performed as a prospective study conducted with a controlled semiexperimental pattern in matched groups. Totally 30 patients including 15 intervention and 15 control group patients matched in terms of socio-demographic features were monitored for 6 months. The intervention group was trained and monitored by a professional team in line with the components of the model. Life quality scale, hypertension information questions, and chronic care assessment scale were applied to both groups at the beginning and in the sixth month of the study. Results: In the intervention group, positive developments were observed such as improved life quality, improvement in metabolic values, increase in knowledge levels, and satisfaction with chronic care management, and additional comorbidity, which facilitates the end-organ damage of hypertension, was not detected. Conclusions: It was determined that the educational intervention conducted through chronic care model turned out to be influential in terms of improving the metabolic signs and quality of life of patients with hypertension

ANALYSIS OF REUSABILITY OF ThO2 AND SPENT UO2 FUELS ENRICHED WITH ADS IN A CANDU REACTOR

The study presents the analysis of the reusability of ThO2 and spent UO2 fuels enriched in two different ADS reactors fuelled with Minor Actinide. The spent UO2 fuels are taken out from pressurized water reactor and CANDU spent fuels. For this analysis, the CANDU-37 reactor having a total fission thermal power of 2156 MW is considered and 14 different cases of enriched fuels taken from the previous enrichment processes are analysed by burning in this reactor. The 3-D and time-dependent critical burn up calculations are carried out by using the MCNP 2.7 code. To determine the effective burn time of each case, these calculations are performed until the values of kinf decrease to about the criticality thresh old of 1.05 for all investigated cases. The percent ages of the Pu-239 and U-233 fissile isotopes appear to be below weapons-grade plutonium and uranium, respectively, in all enriched fuel cases. At the end of effective burn times, the burnup values can reach the values varying in the range of 26.770 and 33.540 GWd/MTU which are a mean of 3.5-4.5 times the burnup value of the CANDU-37 reactor fed with the NatUO(2) fuel. The results of this study bring out that in terms of energy production, the CANDU-37 reactor fuelled with the ThO2 and spent UO2 fuels enriched in ADS designs demonstrates higher neutronic performance than the conventional CANDU-37 reactor