Predictive power of different obesity measures for the presence of diastolic dysfunction

Objective: Body mass index (BMI) and waist circumference (WC) as measures of obesity have some limitations. The aim of this study was to evaluate whether one measure could predict the presence of diastolic dysfunction (DD) more accurately than the other measures. Methods: A total of 91 obese patients without any other risk factors for DD were prospectively enrolled. Echocardiographic examination was performed. DD was defined and categorized according to recent guidelines. The study participants were divided into 2 groups according to the presence of DD. Weight, height, and WC were measured; BMI and waist-to-hip ratio (WHR) were calculated; and a body shape index (ABSI) was calculated as WC/(BMI2/3height1/2). The associations between ABSI, BMI, WHR, and WC and the presence of DD were examined using logistic regression analyses. Analysis of covariance was used to examine the differences. Results: WC and BMI were significantly greater in subjects with DD (p=0.049 and 0.051, respectively). A greater BMI, WC, and WHR increased the risk of the presence of DD (BMI-DD: odds ratio [OR]=1.096, p=0.024; WC-DD: OR=1.059, p=0.007; WHR-DD: OR=2.363, p=0.007). After adjustment for age and sex, only BMI continued to be significantly associated with DD (p=0.031). ABSI was not associated with DD. Conclusion: After adjustment for age and sex, BMI was the only predictor of DD in obesity. Despite its limitations, BMI may still be a potentially more accurate measure of DD compared with other obesity measures. © 2018 Turkish Society of Cardiology

Polimerik Güneş Hücrelerinde Ag Nanopartikül Katkılı TiO2 Tampon Tabakasının Kendiliğinden Organize Olan Tek Tabaka Moleküller (SAM) ile Modifiye Edilmesi

Organik güneş hücrelerinin performansları üzerinde yüzey modifikasyonu ve metal nanopartiküller önemli bir rol oynamaktadır. Tek tabaka kendiliğinden organize olan (self assembly monolayer, SAM) organik malzemeler ucuz ve kolay uygulanabilir olmaları nedenleriyle diğer yüzey uygulama tekniklerine alternatif bir malzemelerdir. Metal nanopartiküllerin organik güneş hücrelerinde uygulama alanlarının geliştirilmesi son yıllarda önemli bir başlık haline gelmiştir. Bu çalışmada, sol-jel yöntemi ile sentezlenen TiO2 elektrot yapısına Ag np’ler katkılanmış ve Ag-/TiO2 yüzeyi SAM molekülü ile modifiye edilerek yeni bir tür elektrot tasarlanmıştır. TiO2 elektrotlu güneş hücresinde elde edilen verimlilik değeri % 2,25 iken, bu çalışmada tasarlanan Ag-TiO2/SAM elektrot yapısından elde edilen güneş hücre verimliliği % 2,84 olarak bulunmuştur

Plasma homocysteine is associated with ischemic findings without organic stenosis in patients with slow coronary flow

AbstractAimTo investigate the plasma concentrations of homocysteine (Hcy) in slow coronary flow (SCF) patients before and at the end of the exercise test and compare with the values of healthy controls.MethodsStudy population consisted of 41 patients with SCF [68% men, aged 49±8 years], and 41 subjects with normal epicardial coronary arteries [56% men, aged 50±9 years]. Exercise test was performed in all study participants. Blood samples were drawn at rest and immediately at the end of exercise testing after 12h of overnight fasting.ResultsThe baseline Hcy value of the SCF patients was higher than that of the control subjects (p<0.0001), and this difference continued after exercise test between the groups (p<0.0001). Median post-exercise increases in Hcy levels were higher in the SCF group than in the control group, without a significant difference (p=0.088). In the SCF group after exercise, Hcy levels in 17 patients with angina and 18 patients with ST depression were higher than those without angina and ST depression (p<0.0001 and p<0.0001, respectively). In addition, Hcy values in patients with both angina and ST depression were greater than those with either angina (p<0.05) or ST depression (p<0.05).ConclusionThe results of this study show that there is an important pathophysiologic link between the increased levels of plasma Hcy, the degree of ischemic findings, and the severity of slow flow in SCF patients

Energy efficiency improvement of the heat pump by employing synthesized CuO/ZnO hybrid nanofluid

WOS:000729464600001In this experimental study, CuO/ZnO hybrid nanoparticles were synthesized by the co-precipitation method. While solid nanoparticles were synthesized, 5%, 10%, and 15% mass fractions of CuO were doped into ZnO nanoparticles. While preparing the nanofluids, sodium dodecyl benzene sulphonate (SUBS) surfactant material was used to prepare a homogeneous and hydrophobic suspension. The results of physical and chemical analyses of the synthesized nanoparticles were examined. In the experiments made with the heat pump, the coefficient of performance (COP) of the heat pump was calculated as 4.23 when deionized water was used as the working fluid. In the experiments with nanofluids using ZnO and 15% (wt./wt.) CuO/ZnO instead of deionized water, COP values of 4.31 and 4.44 were obtained, respectively

The impacts of synthesized Ag doped ZnO nano-materials on the energy efficiency of the refrigeration system

WOS:000787868000001Nanofluids are used to increase thermal performance in various applications of heat transfer. In the present study, to increase the performance of the cooling system, nanolubricant prepared with zinc oxide (ZnO) and silver (Ag) doped ZnO nanoparticles were used. ZnO and Ag/ZnO nanoparticles were synthesized via precipitation and co-precipitation methods, respectively. The effects of Ag particles added to ZnO nanoparticles at the rate of 5% on thermal performance were investigated. XRD and SEM examinations of the synthesized nanoparticles were made in detail and their suitability was determined. Nanolubricants were prepared by mixing 0.5% and 1.0% (wt./wt.) ZnO or Ag/ZnO and 0.5% (wt./wt.) Tween 80 (T80). The coefficient of performance (COP) values maximum increased by 18.20% and 23.68%, respectively, in the use of mineral oil with added 1.0% ZnO and 1.0% Ag/ZnO nanoparticles in the nanolubricants. In the cooling system, the compressor work decreased by 18.71% using the nanolubricant prepared with Ag-doped ZnO hybrid nanoparticles at a 1.0% mass fraction

Effect of ZnO concentration on efficiency in organic solar cells

Bu çalışmada, sol-jel yöntemi ile sentezlenmiş ZnO molaritesinin P3HT (Poli (3-hekzil tiyofen)):PCBM ((6,6) Fenil-C61-Bütirik asit metil ester) aktif tabakalı güneş hücresinde verime olan etkisi incelenmiş ve 0,1, 0,3 ve 0,5 M değerlerinde çalışılmıştır. Aygıtların verim değerleri, 100 mw/cm2 güneş ışıması altında Keithley 2400 kaynak ölçer cihazı yardımı ile belirlenmiştir. Ayrıca XRD, UV-Vis ve FESEM teknikleri ile karakterizasyon işlemleri gerçekleştirilmiştir. Yapılan çalışmalar sonrasında 0,1 M sentez konsantrasyonunun, en uygun koşul olduğu bulunmuş ve bu şartlarda üretilen aygıt ile %3,09 verime ulaşılabildiği tespit edilmiştir.In this study, the effect of the molarity of ZnO synthesized by the sol-gel method on the efficiency of P3HT (Poly (3-hexyl thiophene)):PCBM ((6,6) Phenyl-C61-Butyric acid methyl ester) active layer solar cell was investigated. It was studied at 0.1, 0.3 and 0.5 M values. The efficiency values of the devices were determined with the Keithley 2400 source meter under 100 mw/cm2 solar radiation. In addition, characterization processes were carried out with XRD, UV-Vis and FESEM techniques. After the studies, it was found that 0.1 M synthesis concentration was the most suitable condition and it was determined that 3.09% efficiency could be reached with the device produced under these conditions

Modification of ag nanoparticle doped tio2 buffer layer with self assembly monolayer (SAM) molecule in polymer solar cell

Organik güneş hücrelerinin performansları üzerinde yüzey modifikasyonu ve metal nanopartiküller önemli birrol oynamaktadır. Tek tabaka kendiliğinden organize olan (self assembly monolayer, SAM) organik malzemelerucuz ve kolay uygulanabilir olmaları nedenleriyle diğer yüzey uygulama tekniklerine alternatif birmalzemelerdir. Metal nanopartiküllerin organik güneş hücrelerinde uygulama alanlarının geliştirilmesi sonyıllarda önemli bir başlık haline gelmiştir. Bu çalışmada, sol-jel yöntemi ile sentezlenen TiO2 elektrot yapısınaAg np’ler katkılanmış ve Ag-/TiO2 yüzeyi SAM molekülü ile modifiye edilerek yeni bir tür elektrottasarlanmıştır. TiO2 elektrotlu güneş hücresinde elde edilen verimlilik değeri % 2,25 iken, bu çalışmadatasarlanan Ag-TiO2/SAM elektrot yapısından elde edilen güneş hücre verimliliği % 2,84 olarak bulunmuştur.Surface modification and metal nanoparticles, play an important role on the performance of organic solar cell. Organic materials of self assembly monolayer (SAM) is a alternative material to other surface application techniques due to their cost effective and easy processing. The development of application area of metal nanoparticles, have become an important issue in organic solar cells. In this study, TiO2 electrode, synthesized by sol-gel method, was doped with Ag np's and a novel electrode was designed by modification Ag-TiO2 surface with SAM. While the efficiency of organic solar cell with TiO2 electrode was obtained as 2,25%, the value of efficiency was found as a 2,84% by the use of designed Ag-TiO2/SAM electrode

Effect of Au nanoparticle doped ZnO buffer layer on efficiency in organic solar cells

WOS:000980161000001Although organic solar cells have great potential, there is a need to increase their efficiency values. In this study, ITO/ZnO/P3HT:PCBM/MoO3/Ag structure was used and it was aimed to increase the efficiency by adding different percentages of Au nanoparticles (nps) into the ZnO electron transport layer. According to the best results, adding 10% (V/V) Au into ZnO increased the power conversion efficiency from 2.94% to 3.48%. Thus, efficiency increase of nearly 20% was achieved. The main reason for the increase in efficiency is the increase in current density by utilizing the plasmonic effects of Au nps. While the current density was 8.14 mA/cm2 in the device without Au nps, the 10% Au doping increased to 8.58 mA/cm2 in the device

The effect of ZnO synthesized by different methods on efficiency in organic solar cells

Bu çalışmada ITO/ZnO/P3HT:PCBM/MoO3/Ag yapısına sahip güneş hücresi üretilmiş olup farklı yöntemlerle sentezlenmiş olan ZnO’in aygıt verimi üzerindeki etkisi incelenmiştir. Sentez yöntemi olarak, sol-jel, nanokristal ve çözelti prosesi kullanılmıştır. Öncelikle her bir farklı sentez yöntemi için XRD ile karakterizasyon yapılmıştır. Daha sonrasında ise elde edilen ZnO çözeltileri ile kaplamalar yapılarak aygıtlar üretilmiştir. Yapılan aygıtların verim değerleri, 100 mw/cm2 güneş ışıması altında Keithley 2400 kaynak ölçer cihazı yardımı ile belirlenmiştir. Elde edilen bulgulara göre en yüksek verime (%2,90) sol-jel yöntemiyle sentezlenen ZnO ile ulaşılmıştır. Ayrıca sol-jel yönteminin, diğer yöntemlere göre daha ucuz ekipmanlara ve nispeten zararsız kimyasallara gereksinim duymasından dolayı ekstra avantajları vardır. Sonuç olarak organik güneş hücrelerinde kullanılacak olan ZnO için en uygun sentez yöntemi sol-jel yöntemi olduğu belirlenmiştir.In this study, a solar cell with ITO/ZnO/P3HT:PCBM/MoO3/Ag structure was produced. Then, the effect of ZnO, which was synthesized with different methods, on device efficiency was investigated. As the synthesis method, solgel, nanocrystal and solution processes were used. First of all, XRD characterization has been made for each different synthesis method. Later, the devices were produced by coating with the obtained ZnO solutions. The efficiency of the devices was determined under 100 mw/cm2 solar irradiance using Keithley 2400 sourcemeter. According to the obtained findings, the highest efficiency (2.90%) was achieved with ZnO synthesized by sol-gel method. In addition, the sol-gel method has extra advantages as it requires cheaper equipment and relatively harmless chemicals compared to other methods. As a result, it was determined that the most suitable synthesis method for ZnO to be used in organic solar cells is the sol-gel method