Aksaray Üniversitesi Kurumsal Akademik Arşivi
DSpace@Aksaray, Aksaray Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Cyclic viscoplasticity of semicrystalline polymers with finite strains: observations and constitutive modeling
(World Scientific Publishing Co. Pte Ltd, 2012) Drozdov, A.D.; Düşünceli, Necmi; Klitkou, R.; Christiansen, J. Dec.
Observations are reported on low density polyethylene and isotactic polypropylene in uniaxial tensile cyclic tests (oscillations between maximum elongation ratios kmax and the zero minimum stress σmin with kmax increasing monotonically with number of cycles). Constitutive equations are developed in cyclic viscoplasticity of semicrystalline polymers with finite strains. Adjustable parameters in the stress-strain relations are found by fitting the experimental data. Ability of the model to describe the characteristic features of the mechanical behavior and to predict the viscoplastic response in cyclic tests is confirmed by comparison of the results of numerical simulation with observations in additional tests.
Two-phase model in viscoelasticity and viscoplasticity of semicrystalline polymers
(World Scientific, 2012) Drozdov, A.D.; Düşünceli, Necmi
Observations are reported on isotactic polypropylene in tensile relaxation tests and in loading-unloading tests followed by relaxation after retraction at temperatures ranging from room temperatures up to 100°C. A two-phase constitutive model is developed for the mechanical response of semicrystalline polymers where crystalline and amorphous phases are treated as viscoelastoplastic continua with different laws of plastic flow. Adjustable parameters in the stress-strain relations are found by fitting the observations. Ability of the model to describe characteristic features of the viscoelastic and viscoplastic behavior of polypropylene at various temperatures is confirmed by numerical simulation and comparison of its results with experimental data in additional tests.
Trends in research librarianship literature: A social network analysis of articles
(Igitur, Utrecht Publishing and Archiving Services, 2012) Al, Umut; Soydal, İrem; Alır, Gülten
The purpose of this article is to identify the bibliometric characteristics of research librarianship literature and to visualize relationships in research librarianship by means of social network analysis. It was found out that the majority (66%) of the articles had single authorship and College & Research Libraries is the prominent actor among the research librarianship journals. It was also observed that Peter Hernon is the most productive and cited author in the field. The findings of this study can be used by the research librarianship community to better understand their core literature.
The impact of nutrition on oxidative stress in athletes
(Aksaray Üniversitesi, 2025) Akay, Gülsena; Sözen, Ravza Nur; Öksüz, Abdullah
Exercise can have both beneficial and detrimental effects on oxidative stress, depending on factors such as intensity, duration, and individual characteristics. Particularly, high-intensity and prolonged physical activities increase the production of reactive oxygen species (ROS), which may overwhelm endogenous antioxidant systems and lead to oxidative damage.
Assessment of oxidative stress in athletes commonly involves biomarkers such as lipid peroxidation products [Malondialdehyde (MDA), Thiobarbituric acid reactive substances (TBARS)], protein and DNA oxidation indicators [8-hydroxy-2-deoxyguanosine (8-OHdG)], and antioxidant enzyme activities [Superoxide dismutase (SOD), Glutathione peroxidases (GPx), Catalase (CAT)]. Changes in these parameters during or after exercise provide insight into the level of physiological stress.
Nutrition plays a crucial role in the management of exercise-induced oxidative stress. Western-type diets, which are typically low in antioxidants and high in saturated fats and processed foods, tend to worsen oxidative stress. In contrast, dietary patterns rich in fruits, vegetables, whole grains, healthy fats, and phytochemicals—such as the Mediterranean diet—have been shown to exert protective effects. Regular consumption of bioactive compounds like lycopene (tomatoes), polyphenols (grape juice, green tea, pomegranate, aronia, beetroot), tocopherols (nuts and seeds), and flavonoids (sour cherry, cocoa) can enhance antioxidant capacity and reduce exercise-induced oxidative damage.
However, it is also emphasized that high-dose antioxidant supplementation may impair physiological adaptations and exert pro-oxidant effects. Therefore, a balanced and antioxidant-rich diet based on natural food sources offers a safe and effective approach for managing oxidative stress in athletes without the need for pharmacological interventions.
A review of phenotypic carbapenemase detection methods
(Aksaray Üniversitesi, 2025) Duman, Yücel; Akıneden, Altan; Türkel, Selçuk
Carbapenems are broad-spectrum antibiotics used to treat multidrug-resistant infections caused by Gram-negative, Gram-positive, and anaerobic bacteria. However, the overuse of these antibiotics has led to the rise of carbapenem-resistant bacteria (CRB), which present significant treatment challenges. Carbapenem resistance is primarily mediated by the production of carbapenemase enzymes, which hydrolyze carbapenems and are often encoded by plasmids, facilitating horizontal gene transfer. Rapid detection of carbapenemase-producing organisms is crucial for effective antimicrobial stewardship and preventing the spread of resistance. Phenotypic methods for detecting carbapenemases include disk diffusion, minimum inhibitory concentration (MIC) methods, gradient diffusion, automated systems, and chromogenic media. More advanced techniques, such as the Carba NP test and immunochromatographic assays, provide rapid identification of resistance profiles, while spectrophotometric analysis detects enzymatic hydrolysis. The choice of method depends on sensitivity, specificity, and clinical context. Early and accurate detection allows for timely adjustments to treatment, optimizing patient outcomes and limiting the misuse of broad-spectrum antibiotics.
