Siirt Üniversitesi Kurumsal Akademik Arşivi
DSpace@Siirt, Siirt 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
Equipping Police officers with resources: perceived control of internal states and suicide tendencies among Turkish Police officers, unraveling the serial mediating roles of resilience and depression
(Springer Science and Business Media LLC, 2025-05-08) Mehmet Ali Padır; Caner Doğrusever; Bülent Tansel; Mehmet Sıddık Vangölü
Drawing from existing literature, this study highlights police officers' heightened vulnerability to depression and suicidality as a result of occupational stressors and investigates the intricate associations among Turkish police officers' perceived control of internal states (PCOIS), resilience, depression, and suicidal tendencies. The study uses a comprehensive analysis to investigate how PCOIS influences resilience and depression, which subsequently impact suicidal tendencies. A total of 628 police officers participated in the study voluntarily. The mediation analyses indicate individuals with high PCOIS levels tend to have higher resilience, thus leading to lower suicidality regardless of depression levels. High PCOIS levels have also been linked to lower depression levels, thus also leading to a decrease in suicidality independent of resilience. The study shows both resilience and depression to be affected by PCOIS levels, with resilience acting as a protective shield against suicidality, whereas depression exacerbates the likelihood of suicidality. Lastly, the study has uncovered a serial mediating effect, with higher PCOIS levels enhancing resilience and subsequently reducing depression and suicidal tendencies. Therefore, resilience and depression play crucial roles as serial mediators in the relationship between PCOIS and suicidality, underscoring PCOIS's importance in psychological interventions aimed at bolstering resilience and mitigating depression and suicidality among police officers. This study contributes uniquely to the literature by demonstrating PCOIS's protective role in a high-stress profession and provides practical implications for developing targeted mental health interventions.
Rating of in vitro cytotoxicity activities and anti-xanthine oxidase activities of some non-proteoneogenic amino acid derivatives by molecular docking and molecular dynamics studies
(Elsevier BV, 2025-09) Zuhal Alım; Serap Yalçın Azarkan; Namık Kılınç; Ebru Akkemik
Hyperuricemia is a chronic disease closely associated with many pathological conditions, including cancer, which occur due to increased uric acid levels. Xanthine Oxidase (XO) facilitates the stepwise conversion of hypoxanthine to xanthine and subsequently to uric acid, serving a crucial function in purine metabolism. XO inhibitors are the most important therapeutic agents for the control of hyperuricemia. The fact that existing XO inhibitors have serious side effects has made it necessary to describe original, impressive inhibitors with minor side effects. In this study, since the close relationship between hyperuricemia and cancer, the inhibition effects of some non-proteogenic amino acid derivatives (1-4) on XO activity and their cytotoxic effects on triple-negative breast cancer cell line (MDA-MB-231) were examined together. The inhibition effects of molecules 1-4 on XO activity were determined by IC50 values, and for XO, IC50 values of 1-4 were found to be 1.338 µM, 1.357 µM, 1.788 µM, 1.228 µM respectively. The cytotoxic effect of the molecules (1-4) on MDA-MB-231 cell lines was investigated by XTT analysis. According to the results obtained, it is seen that the effect of the 2nd (IC50:98.55 µM) molecule is more toxic on the cells than the others and molecule 2 demonstrated significant inhibition of cell migration in MDA-MB-231 cells in a compared to the untreated control. The study was supported by molecular docking and molecular dynamics and ADME analyses. In conclusion, the results of this study may be useful in the design of XO inhibitor drugs for the treatment of hyperuricemia by contributing to the synthesis of new, effective amino acid-derived XO inhibitors with fewer side effects.
Thermal management of photovoltaic panels using configurations of spray cooling systems
(Elsevier BV, 2025-09) Fatih Bayrak; Alişan Gönül; Muhammet Camci
Photovoltaic panels suffer from significant efficiency losses at elevated temperatures, particularly in hot and arid environments. Effective thermal management is therefore essential to maximize energy output and extend system lifetime, as rising cell temperatures severely reduce photovoltaic efficiency. This study investigates the use of spray cooling systems to enhance photovoltaic panel performance by lowering surface temperatures as a potential solution. It experimentally evaluates 3-nozzle and 6-nozzle configurations using different nozzle diameters (0.2 mm, 0.4 mm, 0.6 mm) and spray distances (150 mm, 200 mm, 250 mm). The results show that spray cooling substantially reduces panel surface temperatures and increases power output. The best performance is achieved with the 6-nozzle system equipped with 0.6 mm nozzles at a 250 mm distance, yielding a 47.2 % reduction in surface temperature and a 30.7 % increase in power output. Thermal imaging confirms that this configuration provides a more uniform surface temperature distribution and mitigates hotspot formation compared to the 3-nozzle system. This work offers a comprehensive experimental analysis of nozzle number, diameter, and spray distance, and demonstrates the strong potential of optimized spray cooling systems to significantly enhance photovoltaic performance in high-temperature and dry climatic zones.
Integration of compost with mineral NPK fertilizers for improving wheat yield and soil health
(Pakistan Journal of Botany, 2024-12-12) Abdul Basir; Sikandar Iqbal; Muhammad Adnan; Mushtaq Ahmad Khan; Rattan Lal; Shah Fahad; Beena Saeed; Manzoor Ahmad; Ibrahim Al-Ashkar; Çağdaş Can Toprak; Zeki Erden; Ayman El Sabagh
Treating the soil with balanced and appropriate fertilizers is vital for obtaining optimum yield and maintaining soil health in a sustainable manner. One of the bottlenecks to sustainable agricultural production is soil depletion due to unbalanced fertilization. To overcome these problems, a pot experiment was carried out, to explore the potential of composts and mineral fertilizers on the soil health, yield and NPK uptake in wheat in calcareous soil. NPK were supplemented through different sources including T1: Control, T2: 100% NPK as compost I (CI), T3: 100% NPK as compost II (CII), T4: 50%NPK each as CI and mineral fertilizers, T5: 50%NPK each as CII and mineral fertilizers, T6: 100% NPK as mineral fertilizers (120: 90: 60 kg ha-1). Significantly taller plants of (92.6 cm), higher spike length (11.60 cm), thousand grain weight (47.54 g), biological yields (9706.2 kg ha-1) and grain yield (4070 kg ha-2) were recorded at T5. Similarly, maximum leaves N content (1.54%) and P content (0.19%), soil mineral N (192.8 kg ha-1), nitrogen use efficiency (36.1 higher over control) and minimum soil pH (7.76) were also recorded were also observed at in pots treated with (50% NPK each as CII and mineral fertilizers) while the organic matter was highest in pots treated with full dose of CI. Therefore, application of NPK 50% each as mineral fertilizers and compost (CII) is recommended for obtaining optimum crop yield and improved soil and crop quality under calcareous soils.
The effect of case hardening on the natural preservation of stone monuments, Fraktin monument, Türkiye
(Springer Science and Business Media LLC, 2025-05-03) Mustafa Korkanç; İsmail İnce; Mehmet Yavuz Hüseyinca; Mehmet Bahadır Tosunlar; Mehmet Ergün Hatır
Case-hardening processes that develop in monuments reduce the porosity of rocks while increasing surface hardness. This situation may contribute to the transfer of cultural stone heritage markers to future generations by limiting the penetration into the rock structure of water, which is the most destructive agent in atmospheric weathering processes. This study focused on the Fraktin relief monument, which was created by the Hittites in the 13th century BCE by carving into the rock surface. The site was investigated to reveal the case-hardening mechanism and its effects on the physical properties of the rock. The geochemical formation mechanism of the surface-hardening process, which contributed to the survival of the Fraktin relief monument, was examined by use of scanning electron microscope–energy dispersive spectrometry (SEM-EDS) and analysis by an inductively coupled plasma–mass spectrometer (ICP-MS). In addition, the effect of the hardening on the physical properties of the rock was investigated with nondestructive tests applied both in situ and in a laboratory. The SEM-EDS and ICP-MS analyses revealed that amorphous silica filled the pores of the rock and created surface hardening. This situation has increased the geotechnical properties of the unit in which the monument was carved, making it more resistant to atmospheric processes.
