Araştırma Çıktıları | Web Of Science

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Implications of continuous positive airway pressure on heart rate variability in patients with obstructive sleep apnea: Does gender matter?
Özlek, B; Özlek, E; Dogan, V; Basaran, Ö; Çil, C; Çelik, O; Biteker, M; Bilge, AR
Objective: This study was designed to determine the effectiveness of continuous positive airway pressure (CPAP) treatment on the improvement of heart rate variability (HRV) and whether gender plays a role in HRV in patients with moderate to severe obstructive sleep apnea syndrome (OSAS). Methods: Consecutive patients with recently diagnosed moderate to severe OSAS underwent continuous synchronized electrocardiographic monitoring and were prospectively considered for inclusion in the study. HRV was analyzed before starting CPAP therapy and 1 year thereafter. The effects of CPAP on HRV were evaluated in men and women separately to ascertain whether there are gender differences in the clinical manifestations of OSAS and whether female HRV responses to CPAP are similar to those of men. Results: A total of 18 patients (10 men, median age: 56 years) were included in the study. There were no significant differences in the baseline clinical characteristics of the male and female patients. After 1 year of CPAP treatment, heart rate decreased (p<0.05) and time domain parameters increased (p<0.05) in both men and women. None of the frequency domain parameters changed in women (p>0.05), whereas the high frequency power measured increased (p<0.05) and the ratio of low frequency to high frequency decreased (p<0.05) in men after 1 year of CPAP treatment. The increase in HRV after 1 year of CPAP therapy was significantly higher in men than in women (p<0.05). Conclusion: CPAP therapy reduced enhanced cardiac sympathetic nerve activity in patients with OSAS assessed according to HRV. The beneficial effect of long-term CPAP therapy on HRV was more pronounced in men.
Serum Levels of Trace Elements in Patients with Prostate Cancer
Kaba, M; Pirincci, N; Yuksel, MB; Gecit, I; Gunes, M; Ozveren, H; Eren, H; Demir, H
Background: Trace elements are major components of biological structures; however, excessive levels of these elements can be toxic. Materials and Methods: In the present study, serum levels of trace elements were measured in 30 patients with newly diagnosed as prostate cancer and 32 healthy volunteer by using furnace atomic absorption spectrophotometry. Results: It was found that there was an increase in serum levels of Co, Cu, Mg and Pb (p<0.05), whereas a decrease in serum levels of Fe, Mn, and Zn levels in patients with prostate cancer (p<0.05). Conclusions: These changes may be important in the pathogenesis of prostate cancers; however, further prospective studies are needed to identify relationships between prostate cancer and trace elements.
Role of vascular endothelial growth factor antagonism on airway remodeling in asthma
Yuksel, H; Yilmaz, O; Karaman, M; Bagriyanik, HA; Firinci, F; Kiray, M; Turkeli, A; Karaman, O
Background: Vascular endothelial growth factor (VEGF) is an important mediator of the neoangiogenesis component of remodeling in asthma. Objective: To evaluate the influence of VEGF blockage on airway remodeling, specifically epithelium thickness, subepithelial smooth muscle thickness, number of mast and goblet cells, and basement membrane thickness, in a mouse model of chronic asthma. Methods: We used 30 BALB/c mice. The control group was not exposed to ovalbumin or any medication (group 1). Other groups were exposed to intraperitoneal and inhaled ovalbumin to achieve chronic asthma. Each of these groups received intraperitoneal saline (group 2), intraperitoneal dexamethasone (group 3), or intraperitoneal bevacizumab (group 4). Histomorphologic examination for epithelium thickness, subepithelial smooth muscle thickness, number of mast and goblet cells, and basement membrane thickness was performed from the middle zone of the left lung. Results: Treatment with anti-VEGF caused significant reduction in epithelial, subepithelial muscle, and basement membrane thickness compared with untreated asthmatic mice (P = .001, P = .03, and P = .009, respectively). Goblet and mast cell numbers were significantly lower in mice treated with anti-VEGF than in untreated mice (P = .02 and P = .007, respectively). Dexamethasone treatment resulted in improvement of all histomorphologic markers, except goblet cell number. Influences of dexamethasone and anti-VEGF on epithelial and basement membrane thickness and mast and goblet cell numbers did not differ (P > .05), but subepithelial muscle layer was thinner in the former (P - .003). Conclusion: VEGF blockage may provide adjunctive therapeutic options as steroid-sparing agents for more effective treatment of remodeling in asthma. (C) 2013 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.
Investigating the physical and quality characteristics and rheology of mayonnaise containing aquafaba as an egg substitute
Ozcan, I; Ozyigit, E; Erkoc, S; Tavman, S; Kumcuoglu, S
This paper aimed to examine the effect of using aquafaba in different ratios (25%, 50%, 75%, 100%) as an egg yolk substitute on the physical, structural, and rheological properties of mayonnaise. Large amplitude oscillatory shear analysis (LAOS) parameters (eta L ' , eta M ' , G'L , G'(M) , e(3) , e(1) , v(3) , v(1)) were evaluated to determine the rheological properties of mayonnaise samples. The droplet size of samples significantly increased and the stability of the emulsion decreased after 50% substitution ratio. The density of mayonnaise significantly increased with increased aquafaba substitution. According to Lissajous curves, egg yolk substitution with aquafaba leads to a decrease in stress values. Aquafaba affected the microstructure of samples and decreased the dissipated and stored energies. The LAOS parameters showed that the sample's behavior is strain stiffening and shear thinning in the nonlinear region. Textural parameters decreased with increased ratio of aquafaba. Significant differences were observed for L*, a*, b* and Delta E values.
Subarachnoid bleeding into the superior cerebellopontine cistern after radiofrequency trigeminal rhizotomy: case report
Savas, A; Sayin, M
Three years' follow up: relationship of maternal depression and anxiety with ever-wheezing
Yilmaz, O; Yasar, A; Ocalan, M; Ay, P; Alkin, T; Hasdemir, S; Yuksel, H
An efficient process for recovery of fine coal from tailings of coal washing plants
Çiçek, T; Cöcen, I; Engin, VT; Cengizler, H
Gravity concentration of hard lignites using conventional jigs and heavy media separation equipment is prone to produce coal-rich fine tailings. This study aims to establish a fine coal recovery process of very high efficiency at reasonable capital investment and operational costs. The technical feasibility to upgrade the properties of the predeslimed fine refuse of a lignite washing plant with 35.9% ash content was investigated by employing gravity separation methods. The laboratory tests carried out with the combination of shaking table and Mozley multi-gravity separator (MGS) revealed that the clean coal with 18% ash content on dry basis could be obtained with 58.9% clean coal recovery by the shaking table stage and 4.1% clean coal recovery by MGS stage, totaling to the sum of 63.0% clean coal recovery from a predeslimed feed. The combustible recovery and the organic efficiency of the shaking table + MGS combination were 79.5% and 95.5%, respectively. Based on the results of the study, a flow sheet of a high-efficiency fine coal recovery process was proposed, which is also applicable to the coal refuse pond slurry of a lignite washing plant.
Experience with mesocaval shunt with autologous jugular vein interposition in patients with Budd-Chiari syndrome
Ilkgul, Ö; Kilic, M; Içöz, G; Zeytunlu, M; Demirpolat, G; Akyildiz, M; Tokat, Y; Parildar, M; Memis, A
Background/Aims: In the present era of interventional. radiology and liver transplantation, the role of mesocaval shunt surgery for portal hypertension in Budd-Chiari syndrome is reviewed. Methodology: This study analyzed the management of 35 patients with Budd-Chiari syndrome between June 1994 and June 2004 in our institution. During this 10-year interval, 31 of the 35 patients with Budd-Chiari syndrome underwent shunt procedures and four patients underwent liver transplantation. Mesocaval shunts were preferred in 27 patients and seven of these patients required prior caval stenting. One portocaval shunt was performed in a patient having a thrombosed mesocaval shunt. In all mesocaval. shunt procedures the patient's internal jugular vein was used as an interposition graft between the superior mesenteric vein and inferior vena cava. In four patients with thrombosed vena cava a mesoatrial shunt was performed using poly-tetrafluoroethylene graft while four patients with established cirrhosis under-went orthotopic liver transplantation. Results: In the group of mesocaval shunts, 3 patients were lost in the early postoperative period with a mortality rate of 11%, 2 of them due to thrombosed shunts and one of them due to pneumonia. The median follow-up was 42 months (6-120 months) and one patient experienced shunt thrombosis and died afterwards due to the complications of portal hypertension. In the whole series the patency rate of the mesocaval shunt was 89%. Conclusions: Patients with Budd-Chiari syndrome can be managed by a combination of shunt surgery, interventional radiology and liver transplantation. Our results demonstrate the effectiveness of mesocaval shunt procedure with autologous jugular vein interposition to maintain long-term patency and survival.
Microgrid Frequency Regulation and Optimal Sizing of Emergency Generator Considering VSG Coupled Electric Vehicles
Gülkaya, B; Gökçek, T; Ates, Y; Boynuegri, AR
Recently, the transition from conventional to renewable energy sources (RESs), from internal combustion engine vehicles to electric vehicles (EVs), and from the main grid to microgrids (MGs) are essential goals to both reduce greenhouse gas emissions and ensure the stability of power systems. However, the transitions cause new concerns in the grid including technical challenges and financial viability. This study examines the RES-based MG under realistic conditions considering the uncertainty in fleet size of EVs, emergency generator capacity, solar irradiation, and wind speed in island mode. The work aims to provide effective solutions including conventional methods alongside today's trend namely doubly fed electrical generators (DFIG), vehicle-to-grid mechanism (V2G), maximum power point tracking controller (MPPT), voltage source inverter (VSI) with high switching frequency for technical challenges, and virtual synchronous generator (VSG) mechanism for financial viability. The paper provides a guide for resizing the emergency generators capacity depending on system instability. The observations verify that the control mechanisms reinforce the system to remain stable by decreasing the range of frequency fluctuation from 3.1 to <0.05 Hz, the peak point of frequency from 51.8 to 50.05 Hz, and the emergency generator capacity from 0.7605 to 0.3420 MVAr at MATLAB and Simulink.
A Novel Heterozygous STAT5b Variant, N160S, Associated with Modest Short Stature.
Hwa, V; Friedman, NE; Ozhan, B; Fang, P; Derr, MA; Ersoy, B; Rosenfeld, RG
A Comparison between Adomian Decomposition and Tau Methods
Bildik, N; Inc, M
We present a comparison between Adomian decomposition method (ADM) and Tau method (TM) for the integro-differential equations with the initial or the boundary conditions. The problem is solved quickly, easily, and elegantly by ADM. The numerical results on the examples are shown to validate the proposed ADM as an effective numerical method to solve the integro-differential equations. The numerical results show that ADM method is very effective and convenient for solving differential equations than Tao method.
Efficiency of Bioflavonoids in the Prevention of Experimental Myringosclerosis
Ilknur, AE; Dundar, R; Basoglu, S; Inan, S; Aktas, S; Aslan, H; Ozkul, Y; Ozturkcan, S; Katilmis, H
Objectives/Hypothesis: It has been noted that some materials with anti-inflammatory and antioxidant effects decrease sclerotic lesions in experimental myringosclerosis. Our purpose in this study is to investigate the effect of micronized purified flavonoid fraction (MPFF), an antioxidant with anti-inflammatory effects, in experimental myringosclerosis in guinea pigs. Materials and Methods: Two study groups were formed. The first group was administered 100mg/kg/day MPFF by catheter for five days before myringotomy and 10 days after myringotomy, while the second group was administered distilled water by the same method, before and after myringotomy. On the 15th day of the study, after the tympanic membranes were examined otomicroscopically for myringosclerosis, they were removed by dissection together with the bone annulus, for histochemical and immunohistochemical examinations. Results: In the MPFF group, the otomicroscopical sclerosis score, inflammation score and tympanic membrane thickness were significantly less than those in the untreated group (p<0.05). It was also determined that the immunoactivity of the anti-VEGF, anti-TGF-beta, anti-eNOS, anti-iNOS, and anti-IL1-beta primary antibodies, which are known to have an important role in angiogenesis and inflammation, significantly decreased in the MPFF group (p<0.05). Conclusion: In conclusion, this study shows that orally administered MPFF can be efficient in the prevention of experimental myringosclerosis in guinea pigs.
Second law analysis of wind turbine power plants: Cesme, Izmir example
Baskut, O; Ozgener, O; Ozgener, L
In this study, the energy and exergy efficiency results of the Wind Turbine Power Plants (WTPPs) are presented. Exergy, energy and technical availability analysis are performed. The case study includes the actual system data taken from the system in Cesme, Izmir WTPR General energy, exergy and other performance parameters are also presented. Investigated WTPP is Turkey's first installed (1998) wind plant (1.50 MW) located in Izmir. Exergy efficiency of the power plant found to be between 0% and 68.20%. The monthly average technical availabilities are 96.11%, 98.71%, 98.52% for turbine 1, turbine 2, and turbine 3, respectively. Furthermore, authors developed some correlations, which are capable of predicting the values of exergy efficiencies of the WIPP for different power factor value. (C) 2011 Elsevier Ltd. All rights reserved.
Stability of additive-quadratic ρ-functional equations in Banach spaces: a fixed point approach
Park, C; Kim, SO; Alaca, C
Let M(1)f (x, y) : = 3/4 f (x + y) -1/4 f (-x -y) + 1/4 f (x - y) + 1/4 f(y - x) -f (x) -f (y), M(2)f(x, y) : = 2f( x + y/2) + f ( x - y/2 ) + f ( y - x/2 ) -f (x) -f (y). We solve the additive-quadratic rho-functional equations M(1)f (x, y) = rho M(2)f(x, y), (1) and M(2)f(x, y) = rho M(1)f (x, y), (2) where rho is a fixed nonzero number with rho not equal 1. Using the fixed point method, we prove the Hyers-Ulam stability of the additive-quadratic rho-functional equations (1) and (2) in Banach spaces. (C)2017 All rights reserved.
Comparison of the efficacy of lower and higher molecular weight viscosupplementation in the treatment of hip osteoarthritis
Tikiz, C; Ünlü, Z; Sener, A; Efe, M; Tüzün, Ç
We aimed to compare the efficacy of intra-articular injections of a lower molecular weight hyaluronan (LMW HA) (Ostenil) with a higher molecular weight viscosupplement (hylan G-F 20, Synvisc) in hip osteoarthritis. For this purpose, 43 patients (56 hips) with hip osteoarthritis with a visual analogue scale (VAS) pain score higher than 50/100, a Lequesne index greater than 6, and persistence of the pain for longer than 3 months despite all conservative methods were enrolled in the study and randomly assigned to two groups: 25 (32 hips) received LMW HA and the remaining 18 patients (24 hips) received hylan G-F 20. Three injections were administered once weekly to each patient under fluoroscopic guidance. During the 6-month follow-up period, the primary outcomes were assessed at the 1st, 3rd, and 6th month by VAS, WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), and Lequesne index. The intra-articular injections produced a significant reduction in VAS, WOMAC, and Lequesne index scores in both groups. After three injections, improvement was prominent at the 1st month and maintained for 6 months in both groups. The percentage reduction was 38 and 40% (p < 0.001) in VAS pain score, 43 and 40% in WOMAC (p < 0.001), and 47 and 49% in Lequesne index (p < 0.001) in the LMW HA and hylan G-F groups at the 6th month, respectively. However, there were no significant differences in outcomes between any of the measurements at the 1st, 3rd, and 6th month between the two groups (p > 0.05). No systemic adverse effect was recorded. Local adverse effects consisting of pain and/or swelling were noted in 3 of 32 hips (9%) injected with LMW HA and in 3 of 24 hips (12.5%) injected with hylan G-F 20. In conclusion, both types of viscosupplementation produced a significant clinical improvement during the 6-month follow-up period. However, no significant difference was found in outcomes between higher and lower molecular weight hyaluronan.
Microalbumin excretion and outcome in children with multicystic dysplastic kidney
Akil, I; Biyikli, N; Yazici, P; Özyurt, BC; Alpay, H
Aim: To present the long-term follow-up results of children with multicystic dysplastic kidney (MCDK) and urinary microalbumin excretion levels in order to evaluate whether there is an increased risk of renal damage or not. Materials and methods: Thirty-three children with the diagnosis of MCDK who had been followed up by the nephrology outpatient clinic between 2002 and 2009 were invited to participate in the study. Twenty-six healthy children were investigated as a control group for microalbumin/creatinine ratio (mu g/g creatinine). The mean age at diagnosis, the duration of follow-up, accompanying urinary tract abnormalities, attacks of urinary tract infection (UTI), contralateral kidney size, and urinary microalbumin levels were investigated. Results: The mean age of the patients with MCDK and the mean duration of follow-up were 6.5 +/- 3.9 years and 35 months (range 2-96) months, respectively. The most common urinary tract abnormality was vesicoureteral reflux (VUR), with a rate of 34%. Thirty-nine percent of the children experienced UTI during follow-up. The compensatory renal hypertrophy of the contralateral kidney was 24% at 6 months and 68% at 12 months. Sixteen patients (59%) had an increased microalbumin/creatinine ratio (>30 mu g/mg creatinine). Microalbumin/creatinine ratio was higher in patients with MCDK than it was in the controls (P = 0.001). Conclusion: Microalbuminuria and VUR are not rare in children with MCDK. Systematic follow-up of these patients is recommended to identify those at risk of contralateral renal damage.
Renal cell carcinoma: new prognostic factors?
Kirkali, Z; Lekili, M
Purpose of review There are limited independent predictors of survival in patients with renal cell carcinoma. Factors related to the tumor, host and treatment may help us to predict prognosis to a certain extent. Prognostic indicators would enable selection of patients who can benefit from adjuvant therapy and thus should be enrolled in clinical trials. This review highlights developments in the identification of current prognosticators for patients with renal cell carcinoma. Recent findings Tumor stage, grade and patient-performance status are the known prognostic indicators in renal cell carcinoma. Besides these parameters, many molecular and cytogenetic markers were evaluated recently. Unfortunately, none of these parameters appear to be a better predictive prognostic factor than the usual staging and grading. Therefore, efforts to identify new markers for tumor proliferation and progression are still ongoing. It was recently reported that low carbonic anhydrase 9 staining may be an independent poor prognostic factor in patients with renal cell carcinoma. Moreover, there is increasing interest in prognostic indices and predictive algorithms for survival. Staging systems that combine the pathological features with additional prognostic variables have been constructed to predict outcome. The UCLA Integrated Staging System seems to be superior to staging alone in differentiating patients' survival. Summary Although the literature reviewed contains numerous promising clinical, histological, molecular and cytogenetic parameters, none of them has yet been shown to have an independent prognostic value.
MHD mixed convection and entropy generation of nanofluid filled lid driven cavity under the influence of inclined magnetic fields imposed to its upper and lower diagonal triangular domains
Selimefendigil, F; Öztop, HF; Chamkha, AJ
In this study, mixed convection of CuO-water nanofluid filled lid driven cavity having its upper and lower triangular domains under the influence of inclined magnetic fields is numerically investigated. The top horizontal wall of the cavity is moving with constant speed of u(w) with +x direction while no-slip boundary conditions are imposed on the other walls of the cavity. The top wall of the cavity is maintained at constant cold temperature of T-c. while the bottom wall is at hot temperature of T-h and on the other walls of the cavity are assumed to be adiabatic. The governing equations are solved by using Galerkin weighted residual finite element formulation. Entropy generation is produced by using formulation and integrated with calculated velocities and temperatures. The numerical investigation is performed for a range of parameters: Richardson number (between 0.01 and 100), Hartmann number (between 0 and 50), inclination angle of magnetic field (between 0 degrees and 90 degrees) and solid volume fraction of the nanofluid (between 0 and 0.05). Different combinations of Hartmann numbers and inclination angles of the magnetic fields are imposed in the upper and lower triangular domains of the square cavity. It is observed that the local and averaged heat transfer deteriorates when the Richardson number, Hartmann number of the triangular domains increase. When the Hartmann number and magnetic angle of the upper triangle are increased, more deterioration of the averaged transfer is obtained when compared to lower triangular domain. Local and averaged heat transfer increase as the solid volume fraction of the nanoparticles increases and adding nanoparticles is more effective for the local enhancement of the heat transfer when the heat transfer rate is high and convection is not damped with lowering the Hartmann number. Second law analysis of the system for different combinations of flow parameters is also performed. (C) 2016 Elsevier B.V. All rights reserved.
Cardioprotective effects of H3 receptor activation could be double-sided: insights from isoproterenol-induced cardiac injury
Özel, HF; Özbek, M; Özden, MT; Vatansever, HS
Histamine H3 receptors (H3Rs) are known to modulate neurotransmitter release in the nervous system, but their role in cardiac injury remains unclear. The present study aimed to investigate the cardioprotective role of H3Rs in a mouse model of myocardial injury. Forty BALB/c male mice were divided into four groups: Control (SF), Isoproterenol (ISO), Imetit (IMT), and IMT + ISO. The IMT and IMT + ISO groups were pretreated orally with 10 mg/kg imetit-dihydrobromide(imetit) for 7 days. In the last 2 days, the ISO and IMT + ISO groups received a subcutaneous injection of 85 mg/kg isoproterenol to induce myocardial ischemia. Electrocardiogram (ECG) recordings were obtained, and heart tissues were analyzed histopathologically. The results demonstrated that the administration of imetit resulted in the prolongation of the PR interval in the IMT group. QRS and QT intervals were prolonged in the ISO group. The J-wave area in the ISO group was significantly larger than in the other groups. Histopathological analyses revealed the presence of small vacuoles, inflammatory cell infiltration, and collagen aggregates in cardiomyocytes in the ISO group. No significant cellular changes were observed in the IMT group, in contrast. The IMT + ISO group exhibited fewer ischemic findings than the ISO group. Immunohistochemical analyses revealed positive H3R immunoreactivity in all groups. Imetit pretreatment increased the immunoreactivity of H3Rs in both the IMT and IMT + ISO groups. The findings of this study suggest that H3Rs may be present on the postsynaptic side in cardiac myocytes, in addition to adrenergic presynaptic nerve endings. Furthermore, imetit has been found to significantly reduce the effects of myocardial ischemia by activating H3Rs. The better characterization of the postsynaptic role of H3Rs offers potential for the development of new therapeutic strategies.
Experimental and numerical investigation of impact behavior of reinforced concrete slab with different support conditions
Yilmaz, T; Kiraç, N; Anil, Ö; Erdem, RT; Hoskal, V
Reinforced concrete (RC) slabs may be subjected to impulsive dynamic loads such as blast and impact during their service period. Many studies related to the impact behavior of RC slabs have been presented. However, comprehensive studies where the effect of the support conditions on the impact behavior of RC slabs has been investigated are still limited. Thus, this study has focused on the effects of the support types and the support layouts on the dynamic responses and the failure modes of RC slabs subjected to impact loads. In the first part of the study, 9 two-way RC slabs with various support layouts composed of fixed and hinged supports were tested under impact load via the drop-weight test setup. Two different input impact energies were transmitted to RC slabs during impact loading. The time histories of the accelerations and displacements occurred in RC slabs, and the impact loads acting on RC slabs were recorded. The crack patterns due to the impact load were observed. The dynamic responses obtained by experiments have been interpreted in detail. In the second part, a detailed finite element procedure in which explicit dynamic analysis is performed has been introduced for verification of the experimental results. Good agreement between the experimental and the numerical results has been demonstrated. It has been concluded that proposed finite element procedures can be used for evaluation of the dynamic responses and failure modes of RC slabs under low-velocity impact load.

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