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Öğe The effect of serum lipid levels on peripheral blood hematopoietic stem cell levels(Elsevier Ltd, 2021) Yildirim Simsir I.; Donmez A.; Kabaroglu C.; Yavasoglu I.; Basol G.; Gungor A.; Tombuloglu M.Introduction: There are limited numbers of available retrospective studies on various hematological diseases treated with stem cell mobilization therapy. In the present study, we aimed to demonstrate the effects of serum lipid levels on peripheral blood CD34+ (PBCD34+) cell counts as well as the changes in serum lipid levels during stem cell mobilization process. Method: PBCD34+ cell counts were compared between hypercholesterolemic patients and healthy individuals. Additionally, total cholesterol (TChol), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), and triglyceride (TG) levels were measured from healthy donors who underwent stem cell mobilization, at different time points (prior to filgrastim [phase 1], prior to apheresis [phase II], and the first week following apheresis [phase III]. Results: In the hypercholesterolemia group, the PBCD34+ cell count was found to be higher among patients with elevated LDL-C (2.6 ± 0.35/?L vs. 1.7 ± 0.17/?L, p = 0.003) and TChol (2.6 ± 0.34/?L vs. 1.7 ± 0.14/?L, p = 0.006) in comparison to the healthy controls. In the mobilization group, phase II HDL-C levels (35.3 ± 2.8 mg/dL) were found to be lower than both phase I (45.6 ± 2.1 mg/dL) and phase III (44.5 ± 2.6 mg/dL) (p = 0.007). Phase II TChol levels (183.5 ± 10.0 mg/dL) were lower than both phase I (216.8 ± 8.5 mg/dL) and phase III (212.2 ± 8.4 mg/dL) (p = 0.02). At phase II, there was an inverse correlation between PBCD34+ cell count and HDL-C (r = - 0.57, p = 0.003). Discussion: Our results indicate that, while increased LDL-C level is the determinant of baseline PBCD34+ cell count, reduced HDL-C is the determinant of PBCD34+ cell count during mobilization process. © 2021 Elsevier LtdÖğe Energy and exergy analyses of an active magnetic refrigerator(Springer International Publishing, 2014) Ganjehsarabi H.; Dincer I.; Gungor A.In this paper, a thermodynamic model for predicting the performance of active magnetic refrigerator (AMR) is developed using energy and exergy analyses. Through this model, the cooling power, total power consumption, as well as the coefficient of performance (COP), exergy efficiency and exergy destruction rates of an AMR are determined. The effects of increasing mass flow rate on the COP, exergy efficiency and exergy destruction rates of the system are investigated. The results are presented to show that when mass flow rate increases, the COP and exergy efficiency curves reach their maximum values and then slightly decreases with increasing mass flow rate. The rate of exergy destruction increases with increasing mass flow rate due to the pump power requirements. The numerical results show that in order to reach optimal performance, mass flow rate must be adjusted carefully regarding to different operating conditions. © Springer International Publishing Switzerland 2014.Öğe Exergoeconomic analysis of a cascade active magnetic regenerative refrigeration system(Springer International Publishing, 2014) Ganjehsarabi H.; Dincer I.; Gungor A.In this paper, an exergoeconomic analysis of a cascade active magnetic regenerative (AMR) refrigeration system operating on a regenerative Brayton cycle is conducted with respect to various system design parameters. The finite difference method is used in order to solve the set of governing equations, which are highly nonlinear and coupled. In exergy analysis, a thermodynamic model is developed in order to determine exergy destruction rates and calculate the exergy efficiency of the system. In the economic analysis, investment cost rates are calculated with respect to equipment costs, which are determined by cost correlations for each system component, and capital recovery factors. Thus, by combining the two analyses, an exergoeconomic model is created whereby the exergy streams are identified and cost equations are allocated for each component. The results of both exergetic and exergoeconomic analyses show that increasing the fluid mass flow rate decreases the exergy efficiency, and increasing the specific exergetic cooling rate decreases the cost per unit of cooling. © Springer International Publishing Switzerland 2014.Öğe Exergy analysis and environmental impact assessment of a geothermal power plant(Springer New York, 2013) Ganjehsarabi H.; Dincer I.; Gungor A.Geothermal power plants are one of the environmentally benignsystems among other types of power generation systems. In this chapter, the exergy efficiencies and exergy destruction rates are analyzed for the binary geothermal. In addition, greenhouse gas (GHG) emissions (in ton CO2-eq/kWh) during operation as well as the sustainability index are determined under various operating conditions. For the case study presented here, it is shown that the Dora II binary geothermal power plant produces no GHG emissions during operation since no fossil fuels are burned. For the same production capacity, it helps reduce the emissions by 56 Mega Ton CO2-eq/yr compared to a coal-fired power plant and 28 Mega Ton CO2-eq/yr compared to a natural gas combined cycle power plant. © Springer Science+Business Media New York 2013. All rights reserved.Öğe Thermodynamic performance assessment and comparison of active magnetic regenerative and conventional refrigeration systems(Springer Verlag, 2018) Ganjehsarabi H.; Dincer I.; Gungor A.Comprehensive thermodynamic analyses, performance assessments, and comparative evaluations of active magnetic regenerative (AMR) and conventional vapor-compression-based refrigeration systems are presented in this study. The active magnetic regenerative (AMR) uses a magnetic material as a thermal storage medium and as a refrigerating medium. A parametric analysis is to investigate the influences of various operating conditions and/or parameters on the thermodynamic performance of the AMR cycle. In this regard, these performance results are compared with the published experimental data for a traditional refrigeration system with the same refrigeration capacity and temperature span. The results of this particular study show that the COP of the AMR cycle changes very little with varying hot source temperature. It is shown that the conventional vapor-compression-based refrigeration cycles offer better performance than the active magnetic regenerative refrigeration systems. © Springer International Publishing AG, part of Springer Nature 2018.
