Yüzey modifikasyonu yardımıyla CdS toz bazlı hibrit güneş pillerinde performans artışı

The effects of surface modification of CdS through organic Eosin-Y, indoline D205, and Ru-based complex N719 and N3 dyes on CdS-based hybrid solar cells were studied. Chemical bath deposition (CBD) and doctor blade methods were in turn employed to fabricate the CdS specimens on Indium-Tin Oxide (ITO) covered glass substrates. P3HT material with and without dye coatings was covered through a spin-coater on the surface of CdS specimens. Ag paste was then deposited on the surface of P3HT to obtain hybrid solar cells. Structural analysis indicated that CdS powders showed a cubic growth with the preferred orientation of (111). Morphological analysis demonstrated that CdS powders exhibited hierarchical morphology and the morphology turned to granular structure with some porosity upon deposition of both N3 dye and P3HT layers. Absorption plots indicated that Eosin-Y dye loading led to a rise in the absorbance values of CdS specimens. After dye loading, photoluminescence data of CdS-based heterostructure illustrated a decrement in the luminescence intensity, implying that effective exciton dissociation was obtained. Current density-voltage (J-V) characteristics of the hybrid solar cells depicted that the best overall efficiency was observed for Eosin-Y-modified cell as 0.135%. This proved that surface modification by Eosin-Y dye led to a better interfacial contact between CdS and P3HT bilayer due to the enhancement in the charge separation.CdS-tabanlı hibrit güneş pillerinde, CdS'nin yüzey modifikasyon etkileri organik Eosin-Y, indolin D205 ve Ru bazlı N719 ve N3 boyaları vasıtasıyla incelendi. CdS örneklerini İndiyum-Kalay Oksit (ITO) kaplı cam altlıklar üzerinde büyütmek için, sırasıyla kimyasal banyo çökeltme (CBD) ve doktor bıçak yöntemleri kullanıldı. Boya kaplamaları olan ve olmayan CdS örneklerinin yüzeyine P3HT materyali, spin kaplama (spin-coater) cihazı yardımıyla kaplandı. Devamında Ag pasta, hibrit güneş pillerini tamamlamak için P3HT yüzeyine çökeltildi. Yapısal analiz, CdS tozlarının kübik yapıda ve (111) tercihli yönelime sahip olduğunu gösterdi. Morfolojik analiz, CdS tozlarının hiyerarşik morfolojide olduğunu ve morfolojinin hem N3 boyası hem de P3HT tabakasının çökeltilmesiyle birlikte taneli ve gözenekli yapıya döndüğünü gösterdi. Soğurma (absorbsiyon) grafikleri, Eosin-Y boya kaplamasının CdS örneklerinin soğurma değerinde bir artışa yol açtığını gösterdi. Boya kaplamasının, CdS tabanlı heteroyapının fotolüminesans şiddetinde azalma oluşturması, etkin bir eksiton ayrışması elde edildiğini ortaya koymaktadır. Hibrit güneş pillerinin akım yoğunluğu-voltaj (J-V) karakteristiklerinden, Eosin-Y modifikasyonlu güneş pilinin veriminin % 0,135 olarak en yüksek değerde olduğu tespit edildi. Bu durum, Eosin-Y boyası ile yapılan yüzey modifikasyonunun, yük ayrışmasında oluşturduğu iyileşmeden dolayı, CdS ve P3HT ikili yapısının arasında daha iyi bir ara yüzey teması sağladığını ispatlamaktadır

Did diet compliance and remission reduce oxidative stress in celiac patients?

OBJECTIVE: We aimed to examine the effect of remission status on thiol–disulfide homeostasis in celiac patients and thus to indirectly determine the effect of oxidative stress and inflammation caused by non-compliance with the diet. METHODS: Between February 2019 and December 2021, 117 patients diagnosed with celiac disease were included in this prospective randomized and controlled study. In addition to routine tests of celiac patients, thiol and disulfide measurements were made from the blood both at the beginning of the study and at the end of the first year. RESULTS: While 52 of the patients (44.4%) were in remission, 65 patients (55.6%) were not. There was an evident increase in native thiol levels of the patients who were initially not in remission but went into at the end of the first year (347.4±46.7 μmol/L vs. 365.3±44.0 μmol/L; p=0.001). Mean plasma disulfide levels of patients with celiac going into remission became reduced in the first year from the level of 14.5±5.1 μmol/L down to 8.9±4.2 μmol/L (p<0.001). In celiac patients who entered remission, disulfide and anti-tissue transglutaminase immunoglobulin A levels decreased in a correlation (r=0.526; p<0.001). CONCLUSION: Not being in remission in celiac disease leads to increased oxidative stress, and thiol–disulfide homeostasis is an indirect indicator of this. Additionally, providing remission in celiac patients reduces oxidative stress

The Reliability and Validity of The Organizational Cynicism Scale On Health Professionals

Sağlık çalışanlarının, beklentileri karşılanmadığı takdirde, kurumlarına karşı geliştirebilecekleri olumsuz tutum ve davranışları ifade eden örgütsel sinizmin belirlenmesinde kullanılabilecek geçerli ve güvenilir ölçüm araçlarına gereksinim vardır. Amaç: Bu çalışma, sağlık çalışanlarında Örgütsel Sinizm Ölçeği'nin geçerlik ve güvenirliğini sınamak amacıyla gerçekleştirilmiştir. Yöntem: Metodolojik olarak gerçekleştirilen çalışmanın örneklemi İstanbul'da yer alan Sağlık Bakanlığı'na bağlı hastanelerde çalışan hekim, hemşire ve ebelerden oluşan 140 sağlık çalışanından oluşmaktadır. Veri toplama araçlarını sosyo-demografik bilgileri sorgulayan soru formu ve Örgütsel Sinizm Ölçeği oluşturmaktadır. Ölçeğin geçerlik ve güvenirliğini sınamak için kapsam geçerliği, madde analizi, açıklayıcı ve doğrulayıcı faktör analizleri ile iç tutarlılık katsayısı kullanılmıştır. Bulgular: Ölçek ifadelerinin kapsam geçerlik indeksinin .80 ve madde toplam puan korelasyon değerlerinin .59 - .91 aralığında ileri derecede anlamlı olduğu bulunmuştur (p &lt; .001). Ölçek alt boyutlarının iç tutarlık katsayıları .86 - .93 ve ölçek bütününde ise α = .94 olarak hesaplanmıştır. Açıklayıcı faktör analizi sonucunda, ölçek maddelerinin faktör yüklerinin .54 - .85 aralığında olduğu ve uygulanan doğrulayıcı faktör analizinde ise, uyum indekslerinin iyi ve kabul edilebilir uyum gösterdiği saptanmıştır. Sonuç: Bilişsel, duyuşsal ve davranışsal olarak 3 alt boyut ve 14 maddeden oluşan Örgütsel Sinizm Ölçeği'nin sağlık çalışanlarında uygulanabilecek geçerli ve güvenilir bir ölçek olduğu belirlenmiştir. Background: It's needed to use valid and reliable measurement tools for determining Organizational Cynicism that represents negative attitudes and behaviors which health professionals may develop against the institutions if their expectations are not met. Objectives: The current study was conducted to measure the reliability and validity of the Organizational Cynicism Scale on health professionals. Methods: The sample of the methodologically conducted study is composed of 140 health workers who are pyhsicians, nurses and midwives which employed in Hospitals of Ministry of Health in Istanbul. Sociodemographic information included questionnaire and Organizational Cynicism Scale are used as data collection tools. For testing the reliability and validity of the scale, content validity, item analysis, exploratory and confirmatory factor analysis and internal consistency were used. Results: Content validity index of the scale .80 and item total score correlation values of the scale were found very significantly between .59 - .91 (p &lt; .001). Internal consistency coefficients for the subdimensions .86 - .93; and total of the scale's Cronbach's alpha cofficient value was found α = .94. The result of the exploratory factor analysis, factor loadings of the scale items ranged from .54 to .85 and the result of the applied confirmatory factor analysis, fit indexes showed a good fit, and acceptable accordance. Conclusion: It was determined that the Organizational Cynicism Scale which includes 14 items and three sub-dimensions; cognitive, affective and behavioural is a valid and reliable tool that can be applied on health professionals

The effect of acute myocardial infarction on bi-atrial functions

Akut miyokard infarktüsü (Mİ), iskemiye bağlı ilerleyici miyokardiyal hasarının yol açtığı ventriküler disfonksiyon ile birliktedir. Ventriküler kompliyanstaki azalma, sol atriyal basıncı arttırarak atriyal miyokardiyal gerilmeye ve dilatasyona neden olur. Atriyal gerilim ve sol ventrikül basınç artışı kardiyak peptid sekresyonunun primer uyaranıdır. Atriyumlardan salınan başlıca peptid olan ANP ve sol atriyal hacim artışı, Mİ sonrası sağkalımın güçlü prediktörleridir. Bu çalışmanın amacı, akut Mİ geçiren hastalarda, atriyal fonksiyonların ekokardiyografik ve biyokimyasal yöntemler kullanılarak incelenmesi ve koroner lezyon ile ilişkisinin araştırılmasıdır.Gereç ve Yöntem Çalışmaya, akut ST yükselmeli Mİ geçiren 110 hasta dahil edildi. Müracaatın ilk 12 saatinde, antekübital venden alınan kan numunelerinden ELISA yöntemi kullanılarak plazma NT-proANP düzeyleri ölçüldü. Transtorasik ekokardiyografi kullanılarak sol ventrikül sistolik ve diyastolik fonksiyonları değerlendirildi, atriyal alan ve volüm ölçümleri yapıldı. Koroner anjiografi yapılan hastaların filmleri incelenerek Gensini ve damar skorları hesaplandı. NT-proANP seviyeleri ile ekokardiyografik ve anjiografik değişkenlerin ilişkisini değerlendirmek için korelasyon analizi yapıldı. Değerler ortalama ± standart sapma olarak ifade edildi. Tüm testler için iki taraflı p değerinin <0.05 olması istatistiksel olarak anlamlı kabul edildi.Bulgular Çalışmaya alınan hastaların büyük bölümü (%85.5) orta yaşlı (ort. 58,1 yaş), sigara içicisi (82 hasta, %74.5) erkeklerdi. NT-proANP seviyeleri normalin iki katından fazla artmıştı (ort. 3.90 nmol/L). Hastaların yaklaşık yarısında (62 hasta, %56.4) infarktüs kalbin ön yüzüne lokalizeydi. Primer perkütan koroner girişim (PKG), hastaların çoğunluğunda uygulanan revaskülarizasyon yöntemiydi (%81.8). Plazma NT-proANP seviyeleri, yaş, müracaat diyastolik kan basıncı, pik troponin I değeri ile koreleydi. PKG yapılan hastaların NT-proANP düzeyleri daha yüksekti ( p=0.03). Çok değişkenli lineer regresyon analizi sonucu sol atriyum hacmi ile NT-proANP arasında bağımsız bir ilişki tespit edildi.Sonuç Çalışmamızda, akut Mİ geçiren hastalarda sol atriyum boyutları ile plazma NT-proANP seviyelerinin korele olduğunu tespit ettik. Akut Mİ geçiren her hasta için, kardiyovasküler olay riski ve daha yoğun tedavi ve takip gerekliliğinin tayini maksadıyla basit ve kullanışlı bir yöntem olan sol atriyal hacim ölçümünün yapılmasını öneriyoruz.Acute myocardial infarction (AMI) is releated with ventricular dysfunction due to ischemia induced progressive myocardial damage. The decrease in ventricular compliance causes left atrial dilatation and stretching the atrial myocardium by increasing left atrial pressure. Left atrial stretch and left ventricular pressure overload are the main stimuli for secretion of cardiac peptides. Atrial natriuretic peptide (ANP) is the major cardiac peptide secreted from the atria. ANP and increased left atrial volume are powerful predictors of mortality after AMI. The aim of this study is to evaluate atrial functions of the patients early after AMI with echocardiographic and biochemical techniques and assess probable interaction between coronary lesions and atrial functions.Materials and Methods 110 patients with acute ST elevation myocardial infarction have included the study. During the 12 hours after admission, plasma NT-proANP levels of the patients were analysed from the venous blood samples. Left ventricular systolic and diastolic functions were evaluated using transtoracic echocardiography. Atrial area and volumes were also measured. Gensini and vessel scores of the patients that undergone coronary angiography were calculated. To assess the relationship between plasma NT-proANP levels and the echocardiographic and angiographic parameters, correlation analysis was performed. All continuous variables were expressed as mean ± standard deviation and categorical variables as number and percentage. A p value <0.05 was considered to be statistically significant.Results The majority of the patients admitted to the study were middle-aged (mean 58,1 years), smoker (82 patients, 74.5%), men (85.5%). The plasma NT-proANP concentrations of the patients with ST segment elevation AMI were increased significantly (mean 3.90 nmol/L). Most of the patients were presented with acute anterior myocardial infarction (62 patients, 56.4%). Primary angioplasty was performed in most of the patients (81.8%). Plasma NT-proANP concentrations were correlated with age, diastolic blood pressure, and peak troponin I levels. Plasma NT-proANP levels were also increased significantly in patients undergoing primary percutaneous angioplasty (p=0.03) compared with the patients taking fibrinolytics. Multivariate regression analysis showed the independent strong relation between the left atrial volume and the plasma NT-proANP levels.Discussion These results suggest that left atrial dimensions and plasma NT-proANP levels were correlated in patients with AMI. Left atrial volume measurements should be performed for every patient presented with AMI for predicting cardiovascular mortality and discriminating patients who need intensive therapy and follow-up

Clustering epilepsy data with adaptive resonance theory and an epilepsy model

Tez (Yüksek Lisans)-- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2020Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2020Bu tez çalışmasının amacı, yapay zeka alanında son yıllarda daha da dikkat çekmeye başlayan yapay sinir ağı yapılarından biri olarak bilinen ve özellikle mühendislik uygulamalarında öbekleme probleminin çözümünde kullanılan adaptif rezonans teorisine (ART) ilişkin temel yapıyı incelemektir. Adaptif rezonans teorisi aslında primat beyninin anlaşılmasına yönelik bir yapı koyup, davranışları açıklayacak bir model oluşturmak amacıyla önerilmiş ve ilk önerildiği 70'li yıllardan bu yana çeşitli şekillerde temel yapı genişletilerek birçok nörolojik ve davranışsal olguya ilişkin modeller sunulmuştur. Bu tezde ilk olarak temel ART yapısı ele alınacak ve bu yapıya ilişkin diferansiyel denklemlerden yararlanılarak küçük boyutlu bir problemin çözümünde neler olmakta olduğu durum uzayındaki davranışlar elde edilerek açıklanacaktır. Sonra genel olarak kullanılan ART algoritması tanıyılıp, bu algoritma ile asıl yapı arasındaki ilişki açıklanacaktır. Dünya Sağlık Örgütü verilerine göre yeryüzünde 50 milyonu aşkın kişi epilepsi ile başetmek durumundadır ve epilepsi en yaygın nörolojik hastalıktır. Epilepsinin tanısının konulması ve oluşumunda meydana gelen sürecin açıklanması için farklı şekillerde matematiksel modellerden ve bu matematiksel modellere dayanan benzetimlerden yararlanılmaktadır. Tezin bir bölümünde ilk olarak epilepsi hakkında kısa bir bilgi verildikten sonra, önce bir başka yapay sinir ağı yapısı çok katmanlı algılayıcı ile elde edilen sınıflandırma sonuçlarının nasıl elde edildiği açıklanacak, sonra ART yapısı ile öbekleme yapılarak elde edilen sonuç sınıflandırma problemi olarak ele alındığında elde edilen sonuç ile karşılaştırılacaktır. En son olarak da Epilepsi'ye ilişkin verilen bir model olan Jansen modeli ele alınıp bu model ile elde edilen sonuçlar verilecektir.The aim of this thesis is to examine the basic structure of the adaptive resonance theory (ART), which is known as one of the artificial neural network structures used for clustering. It started to draw attention in the field of artificial intelligence, especially in engineering applications, but adaptive resonance theory was originally proposed to establish a model for understanding the primate brain, and to explain behaviors. ART has been used to model many neurological and behavioral phenomena and it is developed by expanding the basic structure in various ways since the 70s. In this thesis, the basic ART structure will be discussed first and its structure will be given by the differential equations. How these differential equations define the processes each substructure realize will be explained by giving state space results for a simple example. Then, the ART algorithm used in machine learning applications will be introduced and the relationship between this algorithm and the actual structure will be explained. According to the data of the World Health Organization, more than 50 million people in the world have to cope with epilepsy, and epilepsy is the most common neurological disease. Different forms of mathematical models and simulations based on these mathematical models are used to diagnose epilepsy and explain the process occurring in its formation. In the second part of the thesis, after brief information about the epilepsy data is given, the data classified by multi-layer perceptron. The same data then is considered without labels and clustering results are obtained with dynamic ART structure and algorithmic ART structure. Finally, the Jansen model, which is a model related to Epilepsy, is introduced and the results obtained with Jansen model is discussed using power spectrum analysis and state space representation.Yüksek LisansM.Sc

Efficacy of statins on sirtuin 1 and endothelial nitric oxide synthase expression: The role of sirtuin 1 gene variants in human coronary atherosclerosis

WOS: 000351832200002PubMed ID: 25582759Statins are 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and are used to reduce the risk of coronary artery disease (CAD) due to their pleiotropic effects. Recently, greater focus has been placed on the role of sirtuin 1 (SIRT1) in cardiovascular disease research. However, insufficient data exist on the relationships between statins, SIRT1 protein levels, and SIRT1 gene variants. In the present study, we investigated the effects of statins, atorvastatin and rosuvastatin, in CAD patients by analysing the associations between SIRT1 gene variants, rs7069102C>G and rs2273773C>T, and SIRT1/endothelial nitric oxide (eNOS) expression, as well as total antioxidant and oxidant status, and the oxidative stress index. SIRT1 expression was significantly higher, and eNOS expression was significantly lower in CAD patients when compared with controls. Statin treatment reduced SIRT1 expression and increased eNOS expression, similar to the levels found in the control population, independent from the studied SIRT1 gene variants. Oxidative stress parameters were significantly increased in CAD patients, and were decreased by statin treatment, demonstrating the antioxidative effects of statins on atherosclerosis. These results indicate that statin treatment could produce its protective effect on cardiovascular disease through the inhibition of SIRT1 expression. This is the first study reporting on the effect of statins, specifically atorvastatin and rosuvastatin, on SIRT1 expression in CAD patients

Fabrication of CdS nanospheres-based hybrid solar cells having increased efficiency

The impact of surface modification through diverse dyes (Eosin-Y, D205, N719 and N3) on structural, morphological, optical, and electrical properties of CdS/P3HT hybrid solar cells is studied. X-ray diffraction (XRD) pattern shows that CdS nanospheres have a hexagonal structure with a preferential orientation of (002) with respect to indium tin oxide (ITO) coated glass slide. Scanning electron microscopy (SEM) results indicate that compact and dense spherical morphologies of CdS occurred, and the P3HT layer also consisted of small spherical grains. The bandgap of CdS is found to be 2.52 eV according to Tauc's plot analysis. Absorption spectra demonstrate that interfacial modification via each dye leads to an increase in the absorption in the wavelength range of 300-1000 nm. Photoluminescence (PL) data prove that surface modification of CdS nanospheres with diverse dyes causes a decrease in the spectral intensity of PL curve, implying that efficient exciton separation is taking place upon dye loadings. Fabricated devices with and without modification show photovoltaic effects that can be seen from current density-voltage (J-V) curves obviously, and the highest power conversion efficiency (PCE) is obtained as 0.881% for N719-modified (ITO/CdS/N719/P3HT/Ag) device (almost 70-fold of pristine one) with a short-circuit current density (J(sc)) of 2.878mA/cm(2) and open-circuit voltage (V-oc) of 0.92V, respectively. This enhancement can be attributed to a better surface area between CdS and P3HT after dye modification

A giant right atrial villous myxoma with simultaneous pulmonary embolism

AbstractINTRODUCTIONPrimary cardiac tumors are rare and approximately three quarters of them are benign and up to half of the benign tumors are myxomas. Right atrial villous myxoma with pulmonary embolism is an unusual apparition.PRESENTATION OF CASEA 29 year-old male was admitted to our outpatient clinic with progressive exertional dyspnea, chest pain and intermittent feeling faint. A giant right atrial villous mobile mass was detected by means of transthoracic echocardiography. To exclude possible pulmonary embolism, chest computed tomography scan was performed and showed filling defects in the branch of the pulmonary artery. The mass was totally resected.DISCUSSIONRA villous myxoma is a rare subtype in an unusual location with high potential of pulmonary embolism. Early surgery for villous myxoma has a great importance in order to reduce the risk of pulmonary embolism.CONCLUSION3D TEE should be a sufficient technique for diagnosis and evoluation of shape, size and origin of the cardiac mass an adequate guide to surgical treatment

Neutrophil-to-lymphocyte ratio and in-hospital mortality in patients with acute heart failure

OBJECTIVES: Previous studies have demonstrated the role of inflammation in acute heart failure. The neutrophil-to-lymphocyte ratio was found to be a useful inflammatory marker for predicting adverse outcomes. We hypothesized that an elevated neutrophil-to-lymphocyte ratio would be associated with increased mortality in acute heart failure patients. METHODS: The study cohort consisted of 167 acute heart failure patients with an ejection fraction <50%. The primary endpoint was in-hospital mortality, and the patients were divided into two groups according to in-hospital mortality. RESULTS: In a multivariate regression analysis, including baseline demographic, clinical, and biochemical covariates, the neutrophil to lymphocyte ratio remained an independent predictor of mortality (OR 1.156, 95% CI 1.001 - 1.334, p= 0.048). CONCLUSION: In conclusion, an elevated neutrophil-to-lymphocyte ratio seems to be a predictor of short-term mortality in patients with acute heart failure and a reduced left ventricular ejection fraction