Doctor of Philosophy

dissertationElectrical and Magnetic Field Flow Fractionation (ElFFF, MFFF) methods are two rapidly developing separation and characterization techniques using electrical and magnetic fields that have not been regularly applied to nanoparticle fractionation, separation, and characterization. Currently, several limitations characteristic of both techniques prevent them from being widely used tools in the separation of nanoparticles. In this work, we address the main limitations of both techniques and develop methods to enhance their separation abilities, and particularly their application to nanoparticles. Specifically, one order of magnitude improvement is obtained in the separation capability of the Cyclical ElFFF systems. It is shown that high resolution separations of 15 and 40 nm gold nanoparticles can be achieved by Cyclical ElFFF, for which the separation of particles smaller than 100 nanometers was not demonstrated before. In addition, the first particle based modeling of Electrical Field Flow Fractionation (ElFFF) systems is demonstrated for the first time. The developed particle based simulation code allows visualization of individual particles inside the separation channel, which leads to a better understanding of ElFFF operation and mechanisms. The outputs of the simulation code show good agreement with the experimental results. We have also fabricated a new ElFFF system and tested it with four different channel heights to investigate the effect of channel height on the separation performance of the ElFFF systems. It is also shown for the first time that ElFFF can be used for the separation of magnetic nanoparticles. In previously reported studies, magnetic field driven techniques were used for the separation of magnetic particles. However, in this study, it is revealed that an electrical field driven technique can also be used for the separation of these nanoparticles. A new magnetic field flow fractionation (MFFF) system was designed and modeled using both finite element and particle based simulations. As a change from current magnetic FFF systems, which use static magnetic fields, the new system uses cyclical magnetic fields for the separation of the particles. Finally, a novel passive magnetic microfluidic mixer is designed and fabricated which produces high efficiency mixing at the microscale, without need of an active actuation mechanism

Protective efficiacy of taurine against pulmonary edema progression: experimental study

Re-expansion pulmonary edema (RPE) is an acute, rare and potentially lethal complication [1,2]. Its beginning is sudden and dramatic. The mechanism is not yet fully understood [1]. Some authors suggest that it may occur after rapid re-inflation of a collapsed lung [1]. It was reported by other authors that it may relate to surfactant depletion or may result from hypoxic capillary damage, leading to increased capillary permeability [1,3]. In RPE, unilateral lung injury is initiated by cytotoxic oxygen metabolites and temporally associated with an influx of polymorphonuclear neutrophils [1]. These toxic oxygen products are the results of re-oxygenation of a collapsed lung. Treatment of re-expansion pulmonary edema is basically preventive [4]

Protective efficiacy of taurine against pulmonary edema progression: experimental study

Re-expansion pulmonary edema (RPE) is an acute, rare and potentially lethal complication [1,2]. Its beginning is sudden and dramatic. The mechanism is not yet fully understood [1]. Some authors suggest that it may occur after rapid re-inflation of a collapsed lung [1]. It was reported by other authors that it may relate to surfactant depletion or may result from hypoxic capillary damage, leading to increased capillary permeability [1,3]. In RPE, unilateral lung injury is initiated by cytotoxic oxygen metabolites and temporally associated with an influx of polymorphonuclear neutrophils [1]. These toxic oxygen products are the results of re-oxygenation of a collapsed lung. Treatment of re-expansion pulmonary edema is basically preventive [4]

Aortic Wall Injury: Intimal Flap Formation after Aortic Balloon Valvuloplasty, a Rare Complication

Injury of the aortic wall occurs in about 15% of patients after balloon aortic valvuloplasty. Formation of an intimal flap is a rare type of vessel wall injury, which is not well recognized yet. We report a case of a newborn with critical aortic stenosis who had an aortic wall injury after balloon aortic valvuloplasty

25-Hydroxy vitamin D levels in premenopausal Turkish women with uterine leiomyoma

We aimed to evaluate the relationship between serum 25-hydroxy vitamin D levels and the risk of uterine fibroids in premenopausal women in Turkish population in this prospective observational cross-sectional study. Sixty-eight women with at least one uterine leiomyoma >= 10 mm were compared with 56 healthy controls. Serum 25-(OH) vitamin D-3 levels were measured by electrochemiluminescence immunoassay. The groups were similar in terms of age, BMI, gravidity and parity numbers. The mean level of 25-(OH) D3 were 7.28 +/- 4.94 ng/ml and 78% of patients (n=97) had severe vitamin D deficiency (<10 ng/mL). Vitamin D levels were significantly lower in the study group (6.54 +/- 4.66 ng/ml vs. 8.18 +/- 5.16 ng/ml, respectively; p=.009). Vitamin D levels were not correlated with size, volume, localization and number of leiomyomas. Traditional covered clothing style, low education level and being housewife were risk factors for Vitamin D deficiency. This is the first study that investigates the vitamin D levels in women with leiomyomas in Turkish population. Influence of vitamin D on uterine leiomyoma formation to may lead to new preventive strategies in the future

Yang Mills Matris Modelleri, Fuzzy Uzaylar ve Kaotik Dinamik

Bu projede kütle deformasyon terimleri içeren Yang Mills matris modellerinde ortaya çıkan kaotik dinamiğin, somut modeller üzerinde analitik ve nümerik yöntemler kullanılarak çalışılmasına odaklanılacaktır. Bu çerçevede ilk aşamada M-(atrix) teorisi ile ilgili modeller olan BFSS matris kuantum mekaniği modeli ve ABJM ayar teorisinin 0+1 boyuta indirgenmiş halinin deformasyonları ele alınması düşünülmüş olup, bu modellerde bulunan arka plan ayar alanlarının hareket denklemlerinden gelen sınırlayıcı koşulları sağlayan ve kolektif zaman bağlılığı içeren matrisler alanları kullanılarak etkin eylemlerin elde edilmesi planlanmıştır. İkinci aşamada ise bu etkin eylemlerin olası kaotik yapıları Lyapunov üstlerinin hesaplanması ve Poincare kesitlerinin belirlenmesi ile ortaya çıkarılması öngörülmektedir