Wos Kapalı Erişimli Yayınlar
Permanent URI for this collectionhttps://hdl.handle.net/11727/10753
Browse
1247 results
Search Results
Item Could Plasma Asymmetric Dimethylarginine Level Be A Novel Predictor Beyond The Classic Predictors of Stent Restenosis?(2014) Bal, Ugur Abbas; Yildirir, Aylin; Aydinalp, Alp; Kaynar, Gamze; Kanyilmaz, Suleyman; Murat, Koza; Muderrisoglu, Ibrahim Haldun; https://orcid.org/0000-0002-9446-2518; https://orcid.org/0000-0001-8750-5287; https://orcid.org/0000-0002-3761-8782; 25233494; AAK-4322-2021; A-4947-2018; AAD-5841-2021Objective: The aim of this study was to investigate the factors associated with coronary stent restenosis and if there is an association between plasma asymmetric dimethylarginine (ADMA) levels and stent restenosis. Methods: Ninety-one patients, who had a history of coronary bare metal stent implantation due to any cause in the last one year period, were admitted to this observational cross-sectional study. Coronary angiography was performed to all patients and quantitative angiography was used to determine the presence of stent restenosis. Laboratory parameters and angiographic features that contribute to stent restenosis were evaluated. Plasma ADMA levels were measured by using high performance liquid chromatography. Logistic regression analysis was used to determine the independent factors of stent restenosis. Results: Angiographic restenosis was found in 35 patients (38.5%). Stent diameter (p=0.038) and left ventricular ejection fraction (p=0.023) were lower and stent implantation history due to acute coronary syndrome (p=0.029), plasma ADMA level (5.0 +/- 1.8x10(-4) mmol/L vs. 3.9 +/- 1.0x10(-4) mmol/L, p=0.001), C-reactive protein concentration (p=0.016), white blood cell count (p=0.044) and stent length (p=0.005) were higher in patients with restenosis. Plasma ADMA level (beta=0.536; OR: 1.710; CI: 1.022-2.861; p=0.041), C-reactive protein concentration (beta=0.062; OR: 1.064; CI: 1.003-1.129; p=0.041), stent diameter (beta=-3.047; OR: 0.048; CI: 0.007-0.313; p=0.002) and length (beta=0.165; OR: 1.179; CI: 1.036-1.343; p=0.013) were found to be the independent predictors of stent restenosis in logistic regression analysis. Conclusion: We conclude that plasma ADMA levels may be used as a novel marker for stent restenosis beyond the classic stent restenosis markers.Item The Role of Nutritional and Dietary Habits in Etiology in Pediatric Vocal Fold Nodule(2022) Korkmaz, Muge Ozcelik; Tuzuner, ArzuObjectives. In pediatric pediatric vocal fold nodule (VFN) patients, different causes have been suggested in the development of the vocal cord nodule, including laryngopharyngeal reflux (LPR). It is known that the content of consumed foods, obesity, and other dietary behaviors are among the risk factors for the devel-opment of reflux. The aim of this study was to evaluate dietary and food consumption habits in pediatric VFN patients.Methods. This prospective-controlled study included 50 children with VFNs (age range 5-14 years) and 50 age-matched children without any voice disorders as a control group. BMI values of each participant were evaluated according to age-percentile range. The voice usage habits and personality structure of all the children were ques-tioned. All patients underwent laryngeal examination and voice analysis. The Turkish Pediatric Voice Handicap Index (t-PVHI) and Child Voice Handicap Index-10 (t-CVHI) were completed by patients or their parents. The examination findings of all patients were evaluated with the reflux finding score (RFS), and their complaints were questioned with the reflux symptom index (RSI). In addition, eating and drinking at night, fast eating and exces -sive food consumption habits and the frequency of consumption of packaged foods defined as junk food, carbon-ated beverage were questioned. The data obtained were compared statistically between the two groups.Results. There was no significant difference between the study and control groups in terms of age, gender distri-bution, median BMI value, voice usage habits, and personality structure. In the study group, t-PVHI, t-CVHI, jit-ter, schimmer values, the mean RFS, and RSI scores were significantly higher than those of the control group. The number of children with high consumption of junk food and carbonated drinks was higher in the study group. There was no significant difference between the two groups in terms of dietary habits.Conclusion. Food consumption habits may play a role in childhood voice problems in this population.Item Differentiation of Memory Processing Stages and Effect of Demographic Variables with Alternative Scoring Approaches To The Rey Auditory Verbal Learning Test(2022) Karakas, Sirel; Bakar, Emel Erdogan; Dogutepe, Elvin; Can, Handan; Kaskati, Tolga; 35670663Background The Rey Auditory Verbal Learning Test (RAVLT) is the third most popular verbal memory test and the tenth most frequently used neuropsychological test. The original scoring system of RAVLT does not differentiate stages of memory processing, but a recently developed composite scoring system has this potential. The objectives were to compare the two systems in terms of their capacity to differentiate the stages of memory processing and to study the effect of demographic variables on the learning trials (T) of the Turkish form of RAVLT (T-RAVLT). Method The sample consisted of 600 Caucasian Turkic adults, who were categorized into three levels of age, three levels of education, and two levels of gender. Individual administration of T-RAVLT was performed using the standard procedures of RAVLT. Results The components in the exploratory factor analysis (EFA) and latent variables in the confirmatory factor analysis (CFA) of the original scores were consistent with sequentially ordered T-RAVLT stages. Demographic variables (age, education, and gender) affected performances in all of the learning trials. The composite scores revealed retrieval and retention as separate components, but these scores could not be predicted from the relevant T-RAVLT scores. Conclusions Findings recommend a combined utilization of the two scoring systems: The original system to provide scores on the performance at each stage of T-RAVLT and the combined system to provide separate scores on learning, retention, and retrieval, the three stages of memory processing. A selective effect of demographic variables on T1 was not observed, indicating a need for cross-cultural studies that are meticulously controlled for age and education.Item Solving A Nonhomogeneous Linear System of Interval Differential Equations(2018) Gasilov, Nizami A.; Amrahov, Sahin Emrah; AAN-9386-2020In most application problems, the exact values of the input parameters are unknown, but the intervals in which these values lie can be determined. In such problems, the dynamics of the system are described by an interval-valued differential equation. In this study, we present a new approach to nonhomogeneous systems of interval differential equations. We consider linear differential equations with real coefficients, but with interval initial values and forcing terms that are sets of real functions. For each forcing term, we assume these real functions to be linearly distributed between two given real functions. We seek solutions not as a vector of interval-valued functions, as usual, but as a set of real vector functions. We develop a method to find the solution and establish an existence and uniqueness theorem. We explain our approach and solution method through an illustrative example. Further, we demonstrate the advantages of the proposed approach over the differential inclusion approach and the generalized differentiability approach.Item A Tabu Search Algorithm for the Training of Neural Networks(2009) Dengiz, B.; Alabas-Uslu, C.; Dengiz, O.The most widely used training algorithm of neural networks (NNs) is back propagation ( BP), a gradient-based technique that requires significant computational effort. Metaheuristic search techniques such as genetic algorithms, tabu search (TS) and simulated annealing have been recently used to cope with major shortcomings of BP such as the tendency to converge to a local optimal and a slow convergence rate. In this paper, an efficient TS algorithm employing different strategies to provide a balance between intensification and diversification is proposed for the training of NNs. The proposed algorithm is compared with other metaheuristic techniques found in literature using published test problems, and found to outperform them in the majority of the test cases.Item A Self-tuning Heuristic for the Design of Communication Networks(2015) Dengiz, Berna; Alabas-Uslu, CigdemThis paper addresses the design of communication networks that has a large application area. The problem is to design a minimum cost network subject to a given reliability level. Complexity of the problem is twofold: (1) finding a minimum-cost network topology that every pair of nodes can communicate with each other and (2) computing overall reliability to provide the reliability constraint. Over the last two decades, metahemistic algorithms have been widely applied to solve this problem due to its NP-hardness. In this study, a self-tuning heuristic (STH), which is a new approach free from parameter tuning, is applied to the design of communication networks. Extensive computational results confirm that STH generates superior solutions to the problem in comparison to some well-known local search metaheuristics, and also more sophisticated metaheuristics proposed in the literature. The practical advantage of STH lies in both its effectiveness and simplicity in application to the design problem.Item A Self-adaptive Local Search Algorithm for the Classical Vehicle Routing Problem(2011) Alabas-Uslu, Cigdem; Dengiz, BernaThe purpose of this study is introduction of a local search heuristic free from parameter tuning to solve classical vehicle routing problem (VRP). The VRP can be described as the problem of designing optimal delivery of routes from one depot to a number of customers under the limitations of side constraints to minimize the total traveling cost. The importance of this problem comes from practical as well as theoretical point of view. The proposed heuristic, self-adaptive local search (SALS), has one generic parameter which is learnt throughout the search process. Computational experiments confirm that SALS gives high qualified solutions to the VRP and ensures at least an average performance, in terms of efficiency and effectiveness, on the problem when compared with the recent and sophisticated approaches from the literature. The most important advantage of the proposed heuristic is the application convenience for the end-users. SALS also is flexible that can be easily applied to variations of VRP. (C) 2011 Elsevier Ltd. All rights reserved.Item A General Neural Network Model for Estimating Telecommunications Network Reliability(2009) Altiparmak, Fulya; Dengiz, Berna; Smith, Alice E.; 0000-0003-1730-4214; 0000-0001-8808-0663; AAF-7020-2021; AAK-2318-2021This paper puts forth a new encoding method for using neural network models to estimate the reliability of telecommunications networks with identical link reliabilities. Neural estimation is computationally speedy, and can be used during network design optimization by an iterative algorithm such as tabu search, or simulated annealing. Two significant drawbacks of previous approaches to using neural networks to model system reliability are the long vector length of the inputs required to represent the network link architecture, and the specificity of the neural network model to a certain system size. Our encoding method overcomes both of these drawbacks with a compact, general set of inputs that adequately describe the likely network reliability. We computationally demonstrate both the precision of the neural network estimate of reliability, and the ability of the neural network model to generalize to a variety of network sizes, including application to three actual large scale communications networks.Item A cross entropy approach to design of reliable networks(2009) Dengiz, Berna; Altiparmak, Fulya; 0000-0003-1730-4214; AAF-7020-2021One of the most important parameters determining the performance of communication networks is network reliability. The network reliability strongly depends on not only topological layout of the communication networks but also reliability and availability of the communication facilities. The selection of optimal network topology is an NP-hard problem so that computation time of enumeration-based methods grows exponentially with network size. This paper presents a new solution approach based on cross-entropy method, called NCE, to design of communication networks. The design problem is to find a network topology with minimum cost such that all-terminal reliability is not less than a given level of reliability. To investigate the effectiveness of the proposed NCE, comparisons with other heuristic approaches given in the literature for the design problem are carried out in a three-stage experimental study. Computational results show that NCE is an effective heuristic approach to design of reliable networks. (C) 2008 Elsevier B.V. All rights reserved.Item Comparison Of Clinical Characteristics Of Second And Third Peaks Of COVID-19 Pandemic: Effects Of Vaccination And Preventive Measures(2022) Ozdemir, Ozer; Arslan, Atakan; Bulbul, Hande M.; Ozdemir, PelinBACKGROUND: Understanding the differences in consequent peaks of COVID-19 may guide us for better predicting future disease characteristics. In this study, we aimed to compare clinical and radiological characteristics as well as out-comes of hospitalized patients with the diagnosis of COVID-19 in second and third peaks of disease.METHODS: We retrospectively included 303 hospitalized patients with COVID-19. The study population was examined in two groups: patients hospitalized between October 2020 and January 2021 during second peak and patients hospital-ized between March and June 2021 during third peak.RESULTS: There were 171 patients in group 1 and 132 patients in group 2. The patients in group 2 were younger (64 +/- 13.27 vs. 56.02 +/- 15.39, respectively; P<0.001) and female proportion was higher (64.9% and 48.5% males; P=0.005). Smoking history and presence of comorbidities were less in group 2 (41.5% vs. 25.7%, P=0.008; and 78.5% vs. 59.1%, P<0.001) and symptom duration was shorter (median 7 days vs. 6 days, P=0.039). CT severity scores, LDH, CRP, D-di-mer, Ferritin, and creatinine levels were lower in group 2 (P=0.003, P=0.008, P<0.001, P<0.001, P<0.001, respectively), and mortality ratio was lower (N.=39 [28%] vs. N.=15 [11.4%], P=0.01). Duration of hospital stay and need for intensive unit care were similar across groups (median 8 days vs. 7 days, P=0.673 and N.=39 [22.8%] vs. N.=33 [25.2%], P=0.683).CONCLUSIONS: Although duration of hospital stay was lower in third peak, clinical severity scores and prognostic markers were lower compared with second peak. These may reflect the increased proportion of immunized people, and the effect of preventive measures.