Gazi University Research Information System
Not a member yet
176130 research outputs found
Sort by
Steroidal arylidene hybrids with phenolic moieties: Integrated in silico, DFT, and electrochemical evaluation for therapeutic targeting
No full textTargeting dual modulators of androgen biosynthesis enzymes, two phenol-substituted steroidal arylidene analogs-Dehydroepiandrosterone-Fn (DHEA-Fn) and Pregnenolone-Fn (PREG-Fn), where "Fn" denotes a phenolic moiety-were structurally characterized and comprehensively evaluated through a multidisciplinary approach integrating spectroscopic, electrochemical, and in silico analyses. Advanced Nuclear Magnetic Resonance (NMR) techniques, including two-dimensional heteronuclear correlation (2D-HETCOR) NMR, confirmed E/Z isomerism in DHEA-Fn and supported precise assignment of regiochemical and stereoelectronic features. Structure-guided molecular docking and molecular mechanics-generalized Born surface area (MM-GBSA) calculations predicted favorable binding to 5 alpha-reductase type 2 and CYP17A1, positioning the compounds as potential dual inhibitors relevant to prostate cancer therapy. DHEA-Fn exhibited a superior docking profile (-10.53 kcal/mol) compared to the positive control Finasteride. Density functional theory (DFT) calculations indicated narrow HOMO-LUMO energy gaps and high electron affinity values, supporting enhanced redox reactivity and antioxidant potential. Electrochemical characterization using cyclic and square wave voltammetry confirmed quasi-reversible redox behavior consistent with the conjugated arylidene-phenol framework. This conjugated arylidene-phenol is proposed to act as a redox-active structural motif (i.e., a moiety capable of reversible electron transfer), potentially influencing bioactivation, oxidative stability, and interactions with redox-sensitive biological targets. In silico ADMET (absorption, distribution, metabolism, excretion, and toxicity) modeling further predicted excellent oral bioavailability, blood-brain barrier permeability, and no violations of drug-likeness rules. Distinct P-glycoprotein interaction profiles suggest variable CNS efflux, which may influence neuroactivity and systemic distribution. Together, the integration of electrochemical analysis and in silico modeling provides a predictive, mechanism-oriented framework for evaluating the therapeutic viability of steroidal scaffolds. These findings highlight DHEA-Fn and PREG-Fn as rationally designed, multifunctional candidates with favorable physicochemical, electronic, and pharmacological profiles for further development in androgen-related oncology
İMPLANT ÜSTÜ PROTETİK RESTORASYONLARDA KULLANILAN ÜST YAPI MATERYALLERİ VE SEÇİM KRİTERLERİ
No full textComparison of in vitro lipolysis, sequential lipolysis – ex vivo permeability, and simultaneous lipolysis - in situ perfusion for exemestane-loaded lipid-based formulations
No full textAssessment of genetic diversity and population structure in alfalfa (Medicago sativa L.) using sequence-related amplified polymorphism (SRAP) markers
No full textDeveloping resilient cultivars with improved tolerance to environmental stresses and stronger resistance to pests and diseases requires pre-breeding efforts focused on understanding genetic diversity. In the present study, 85 alfalfa genotypes were analyzed using sequence-related amplified polymorphism (SRAP) markers. A total of 112 alleles were amplified across 10 SRAP primer combinations, with the number of alleles per primer ranging from 7 to 19. The mean polymorphism information content (PIC) was 0.295, indicating a moderate level of marker informativeness. Genetic diversity parameters, including Nei’s gene diversity (He = 0.27) and Shannon’s information index (I = 0.42), revealed moderate to high levels of genetic variation among the accessions. Cluster analysis based on Dice’s similarity coefficients and the unweighted pair Group method with arithmetic mean (UPGMA) grouped the genotypes into two main clusters. This clustering pattern was further corroborated by principal component analysis (PCA), which showed a clear genetic differentiation among individuals. Bayesian population structure analysis conducted using STRUCTURE software identified K = 2 as the most likely number of genetic subpopulations, as determined by the Delta K method. Most genotypes displayed high membership coefficients (Q ≥ 0.80), suggesting a high degree of genetic homogeneity within subpopulations. Subpopulation B exhibited greater genetic diversity (He = 0.2612) and lower genetic differentiation (FST = 0.2443), whereas subpopulation A appeared more genetically distinct (FST = 0.3952). These results demonstrate the effectiveness of SRAP markers in resolving genetic structure in alfalfa and underscore their utility in identifying genetically diverse and distinct individuals for breeding purposes. Moreover, the absence of clear geographic structuring among the genotypes suggests substantial gene flow across collection sites. This study emphasizes the value of molecular characterization in guiding the selection of parental lines and enhancing germplasm conservation efforts for the improvement of alfalfa cultivars.</p
Effects of the thermal-structural optimization and fin-assisted cooling on the heat dissipation performance of a prismatic lithium iron phosphate battery pack for photovoltaic energy storage
No full textThe effective temperature management for prismatic lithium iron phosphate (LiFePO₄) battery packs in photovoltaic (PV)-based Battery Energy Storage Systems (BESS) is essential for battery performance, lifespan, and safety. In this paper, the thermal-structural optimization on the heat dissipation performance of a prismatic LiFePO₄ battery pack for photovoltaic energy storage with Grey Relation Analysis (GRA) was investigated. The Taguchi experimental design was performed as L9 orthogonal array to analyze the effects of inter-cell spacing (x and y), discharge rate (C-rate), and air velocity on the thermal (cooling) performance by numerical simulation using ANSYS Fluent on the thermal-structural optimization. The optimal structural configuration has identified as inter-cell spacing of x = 20 mm (A2), y = 10 mm (B1), C-rate of 0.7C-rate (C1) and air velocity of 4 m/s (D3). The maximum temperature (Tₘₐₓ), temperature difference (ΔT), compact module volume and the highest thermal-hydraulic performance ratio without fin of the optimum configurations were determined as 308 K, 0.672 K, 22,153 cm3 and 0.49, respectively, corresponding to an 11 K reduction in average temperature and a 3.4 % thermal efficiency improvement with A2B1C1D3. ANOVA identified the C-rate as the leading factor with 81.12 % contribution ratio followed by air velocity (v) with 7.59 %. Subsequently, the effects of cylindrical, conical, and prismatic fin-assisted cooling were investigated on the selected optimal structural design. The temperatures on the cylindrical, conical and prismatic fin-assisted cooling have computed as 304.8 K, 305.3 K and 305.6 K, respectively. The structural without fin exhibits the lowest pressure drop (231 Pa) whereas the conical, prismatic and cylindrical fins have 865 Pa, 811 Pa and 578 Pa pressure drops. The best thermal-hydraulic performance ratio (Φ) was calculated as 0.52 for the cylindrical fin-assisted cooling, which represents an improvement of 6 % compared to the finless structure. The regression equations were developed for lowest and highest temperature (Tmax, Tmin) and the thermal–hydraulic performance ratio (Φ) and the R2 values have calculated high predictive accuracy as 0.998, 0.999 and 0.980, respectively. As a result, this work will provide a significant reference and valuable guidance for designing improved fin-assisted cooling on a prismatic LiFePO₄ battery module in PV-based BESS applications.</p
Copper tailings recycling in cement-based composites: A deterministic LCA approach accompanied by microstructure, mechanical, thermal and non-destructive tests
No full textInnovative approaches to sustainable building materials are needed due to the cement industry's high carbon footprint and the environmental management of massive amounts of copper tailings (CT) from mining operations. Using a comprehensive approach, this study aims to evaluate the thermal-mechanical performance and ecological sustainability of CT, a high-silica (>79 %) and distinctly bimodal grain-distribution material from Artvin-Murgul, as a pozzolanic additive in cement-based composites. To achieve this, mortar series were created in which CT was added to cement at weight percentages ranging from 0 % to 15 %. Mechanical, thermal, microstructural, and pozzolanic activity analyses were employed to evaluate the performance of the samples. A cradle-to-grave Life Cycle Assessment (LCA) employing the EF 3.1 method in compliance with ISO 14040/44 standards was also used to evaluate environmental performance. With a pozzolanic activity index of 76.2 %, the results verified that CT is a pozzolanic material. The 28-day compressive strength was maintained at 52.5 MPa, with the best performance from the 5 % CT replacement. The composite's higher density, however, resulted in a slightly lower specific strength compared to the control sample, underscoring the trade-off between mass efficiency and environmental advantages. Additionally, there was a 2.1 % increase in flexural strength (7.17 MPa). The success of the pozzolanic reaction has been chemically verified through microstructural analyses. The weak Ca(OH)2 phase was consumed by the 5 % CT addition, which significantly decreased the Ca/Si ratio in the matrix and resulted in a more robust C-S-H structure. According to LCA results, applying 15 % CT resulted in notable improvements in Global Warming Potential (GWP) and all impact categories, particularly acidification and eutrophication. A 12.4 % decrease in net lifecycle GWP was computed, taking carbonation effects into account. In addition to enhancing mechanical performance, this study demonstrates that using CT at the optimal rate offers substantial environmental advantages, as evidenced by LCA. This process effectively turns industrial waste into a valuable, eco-friendly building material
Investigation of the hypoglycemic potential of Geranium subcaulescens through activity-guided isolation, employing in vitro, in vivo, and in silico methodologies
No full textGeranium species are utilized as a folk medicine to treat diabetes mellitus in Turkey, Morocco, Algeria, Northern Peru, India.This study aimed to investigate the hypoglycemic activity of Geranium subcaulescens root (GSR) extract using in vitro, in vivo, in silico methods. It was planned to identify the compound(s) responsible for the activity through activity-directed isolation studies from GSR methanol extract and to standardize the extract based on the major compound using High-Performance Liquid Chromatography. The effects of GSR extract and isolated compounds on α-glucosidase, α-amylase, pancreatic lipase, pancreatic cholesterol esterase enzymes were investigated. Four models (normoglycemic model, oral glucose tolerance test, acute, subacute experiments in streptozotocin (STZ)-induced diabetic animals) were used for in vivo studies. The interactions of compounds with α-glucosidase α-amylase enzymes were investigated by molecular docking. The methanol extract strongly inhibited α-glucosidase (IC50 8.68 ± 0.11μg/ml), α-amylase enzymes (IC50 6.77 ± 1.58μg/ml) caused significant hypoglycemic effects in STZ diabetic rats. 3,3′ di-O-methylellagic acid 4′-O-α-rhamnopyranoside, 3,3′,4 tri-O-methylellagic acid 4′-O-α-rhamnopyranoside, geraniin, geranin A, ellagic acid 3-O-α-rhamnopyranoside were isolated. Geraniin was found to have inhibitory activity on both α-glucosidase (IC50 4.512 ± 0.200μg/ml) α-amylase (IC50 2.205 ± 1.500) enzymes and to cause significant hypoglycemic activity (31.74 % at a dose of 50 mg/kg and by 55.41 % at a dose of 75 mg/kg) in STZ-diabetic animals. In silico studies, it was exhibited that geraniin has strong interactions with the relevant enzymes. The findings support the folk medicinal use of Geranium species in treating diabetes. In vitro, in vivo, and in silico study results predicted that geraniin (75.54 mg/g plant), as the major compound, is responsible for the hypoglycemicc activity of G. subcaulescens
Can the presence of SLAP-5 lesions be predicted by using the critical shoulder angle in traumatic anterior shoulder instability?
No full textObjective Although SLAP-5 lesions are associated with recurrent dislocations, their causes and pathomechanisms have not been fully elucidated. This study aimed to investigate the association between SLAP-5 lesions and scapular morphology in traumatic anterior shoulder instability (ASI). We hypothesized that there may be a relationship between SLAP-5 lesions and scapular morphology in traumatic ASI patients. Materials and methods The study included 74 patients with isolated Bankart lesions and 69 with SLAP-5 lesions who underwent arthroscopic labral repair for ASI. Critical shoulder angle (CSA) was measured on the roentgenograms, while glenoid inclination (GI) and glenoid version (GV) were measured on magnetic resonance imaging (MRI) by two observers in two separate sessions blinded to each other. Both groups were compared in terms of CSA, GI, and GV. Results The mean ages of Bankart and SLAP-5 patients were 28.4 +/- 9.1 and 27.9 +/- 7.7 (P=0.89), respectively; their mean CSA values were 33.1 degrees +/- 2.6 degrees and 28.2 degrees +/- 2.4 degrees, respectively (P<0.001). The ROC analysis's cut-off value was 30.5 degrees, with 75.0% sensitivity and 76.7% specificity (AUC = 0.830). SLAP-5 lesions were more common on the dominant side than isolated Bankart lesions (P=0.021), but no difference was found between the groups in terms of GI and GV (P=0.334, P=0.081, respectively). Conclusions In ASI, low CSA values appeared to be related to SLAP-5 lesions, and the cut-off value of CSA for SLAP lesion formation was 30.5 degrees with 75.0% sensitivity and 76.7% specificity. Scapula morphology may be related to the SLAP-5 lesions, and CSA can be used as an additional parameter in provocative diagnostic tests and medical imaging techniques for the detection of SLAP lesions accompanying Bankart lesions. Level of Evidence III retrospective case-control stud