Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(85)
- Serdar, Osman(72)
- Güler, Ömer(68)
- Akkurt, Nevzat(61)
- Baskonus, Haci Mehmet(54)
- Alataş, Mevlüt(53)
- Paksoy, Mehmet Yavuz(53)
- Yucesan, Melih(53)
- Bulut, Hasan(51)
- Tekin, H.O.(51)
- ALMisned, Ghada(48)
- Yildirim, Numan(48)
- Benzer, Fulya(47)
- Kocabaş, Mehmet(45)
- Yildirim, Nuran Cikcikoglu(44)
- Kutlu, Banu(41)
- Ince, Muharrem(39)
- Zengin, Gokhan(39)
- Batan, Nevzat(37)
- Utku, Anıl(35)
- Celik, Erkan(33)
- Topal, Murat(32)
- Ezer, Tülay(31)
- Tanyol, Mehtap(31)
- Can, Erkan(30)
- Sulaiman, Tukur Abdulkadir(29)
- Aslan, Naim(28)
- Özkul, İskender(28)
- Aslan, Alper(27)
- Cakilcioglu, Ugur(27)
- Erguven, Gokhan Onder(27)
- Kutluyer, Filiz(27)
- Kök, Mediha(27)
- Ates, Mehmet(26)
- Erten, Fusun(26)
- Kahraman, Gökhan(26)
- Onat, Onur(26)
- Dal, Nursel Alp(25)
- Danabas, Durali(25)
- Say, Yakup(25)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ3Changes in common carp (Cyprinus carpio) sperm quality and membrane lipid composition related to cryopreservation by Tribulus terrestris; [Alterações na qualidade do esperma e na composição lipídica da membrana da carpa comum (Cyprinus carpio) relacionadas à criopreservação por Tribulus terrestris]
Ölçülü, Abdullatif; Özçiçek, Esin; Kocabaş, Filiz Kutluyer; Kocabaş, Mehmet; Kızak, Volkan; Yilmaz, Ökkeş
Docosahexaenoic acid (DHA) was the major polyunsaturated fatty acid (PUFA) in the sperm plasma membrane, and the levels of PUFAs decreased in treated groups during the cryopreservation process. The supplementation of TT (Tribulus terrestris) to Cyprinus carpio sperm at 200 µg∙L-1 positively affected the maintenance of motility parameters and FAs levels after the freeze-thaw cycle, and TT can be used as an herbal medicine instead of synthetic pharmaceuticals to improve the productive performance in aquaculture.
- MakaleYalnız künye2026Scopus SJRQ3H-SEMI-SYMMETRY IN KÄHLER MANIFOLDS AND APPLICATIONS TO COMPLEX CONTACT MANIFOLDS
Ünal, İnan
Complex manifolds include different subclasses, and one of the most significant ones is the class of Kähler manifolds. These types of manifolds have valuable curvature properties that are related to almost complex structures. For this study, we focused on Kähler manifolds having semi-symmetry conditions associated with H-curvature tensors. Another important subclass is of IK-normal complex contact metric man-ifolds, which are complex manifolds with a contact structure. Since the complex structure of this type of manifold is Kähler, it has important ap-plications. In the last section, we used the results obtained for a Kähler manifold to an IK-normal complex contact metric manifold.
- MakaleYalnız künye2026Scopus SJRQ2A bias-corrected partial bernstein copula approach for nonparametric regression
Susam, Selim Orhun
Multivariate Bernstein polynomials yield smooth, boundary–bias–free estimators for copulas and their derivatives. The classical partial Bernstein copula derivative of Janssen et al. (2016) suffers from an uncorrected first–order bias that can dominate the mean squared error (MSE) in moderate samples. We introduce a simple double–difference correction that removes the entire leading bias term while increasing the variance by a small fixed multiplicative factor only. When this bias–reduced partial derivative is plugged into the copula based regression integral, the resulting estimator achieves substantially smaller bias and uniformly lower MSE than the classical version. Analytic bias–variance expansions are provided, and a comprehensive Monte Carlo study shows up to 50% reductions in MSE across a range of Bernstein copula degrees. A real data application to the mcycle dataset further demonstrates the practical advantages of the method, with the smoothing parameters selected by least squares cross validation (LSCV).
AtıfScopus1WoS1OpenAlex1
İncele - MakaleAçık Erişim2026Scopus SJRQ1The effectiveness of AgNPs synthesized using Aspergillus floccosus for controlling Phoma herbarum and Aphis Pomi de Geer
Aker, Onur; Bektaş, İdris; Yazdıç, Ferit Can
This study was conducted to synthesise silver nanoparticles (AgNPs) using Aspergillus floccosus fungal extract and to evaluate the pesticidal efficacy of the resulting nanopesticide product against two harmful organisms (pathogenic fungus and pest) affecting apples. The synthesised AgNPs were subjected to a series of characterisation tests (UV-Vis, FTIR, XRD, SEM, TEM, EDX, Zeta Potential) and, based on the results obtained, the AgNPs synthesis was successfully completed. Within the scope of this study, the first registration process has been carried out for the fungal pathogen (Phoma herbarum) that causes rot disease in apple fruits. The fungicidal efficacy of five concentrations of AgNPs (10, 25, 50, 100, and 200 mg L⁻¹) was evaluated against this pathogen under both in vitro and in vivo conditions. The results showed that AgNPs exhibited a significant inhibition on the mycelial growth of Phoma herbarum in vitro. The 200 mg L⁻¹ concentration showed the highest inhibition percentage (81.5%). Concerning in vivo test, the effect of AgNPs on disease severity index of Phoma herbarum in apple fruits was evaluated. The result of this part showed that the concentration 200 mg L⁻¹ of AgNPs exhibits highest fungicidal efficacy disease reduction rates (100%), Following by 67% for AgNPs 100 mg L⁻¹. The insecticidal effects of AgNPs on fourth-stage nymphs and adults of the pest (Aphis pomi) were evaluated in laboratory and field applications. For this purpose, AgNPs prepared at five different concentrations (30, 60, 90, 120, and 150 mg L⁻¹) were sprayed on the pests. The results showed that the insecticidal efficacy of AgNPs against Aphis pomi was directly related to both the dose and the exposure time. Specifically, the lethal concentration required to kill adults (LC50: 48.9 mg L⁻¹ for laboratory application and 68.4 mg L⁻¹ for orchard application) was higher than the dose required for nymphs (LC50: 32.3 mg L⁻¹ for laboratory and 52.1 mg L⁻¹ for orchard application). A similar trend was observed for lethal time, with adults exhibiting longer required exposure times (LT50: 51.2 h in the lab and 58.4 h in the orchard) compared to nymphs (LT50: 42.0 h in the lab and 45.1 h in the orchard). According to the results obtained, AgNPs synthesised using Aspergillus floccosus fungus have been proven to be highly effective at low doses against two major harmful organisms that cause qualitative and quantitative losses in apples. In conclusion, it has been proven that this silver-based nano pesticide product can be used as an alternative and innovative product in combating factors that cause agricultural damage to protect apple health.
AtıfScopus1WoS1
İncele - MakaleYalnız künye2026Scopus SJRQ2Simultaneous Leaching and Kinetics of Cu and Zn from Malachite Ore in NH3-NH4NO3 Solutions
Bakici, Zümra; Baysar, Ahmet; Demİrkiran, Nİzamettİn
The simultaneous leaching behavior and kinetics of copper and zinc from malachite were investigated in NH3-NH4NO3 buffer solutions at pH 9.8. The effects of solution concentration, temperature, stirring speed, average particle size, and solid to liquid ratio on the leaching rate were examined. It was observed that the leaching rate of copper and zinc increased with an increase in the solution concentration, temperature, stirring speed, and with a decrease in the solid to liquid ratio and particle size. The findings showed that copper was leached nearly completely depending on the experimental conditions while zinc was dissolved partially. While the concentration of NH3-NH4NO3, temperature, stirring speed, average particle size, solid to liquid ratio, and time were 0.38/0.11 M, 40°C, 500 rpm, 214 µm, 5/500 g/mL, and 240 min, respectively, and the amount of the leached copper and zinc was calculated to be 83.0% and 43.4%, respectively. It was determined that the leaching kinetics fit a mixed-kinetic model. The activation energy values were found to be identical for both copper and zinc leaching (16.22 kJ/mol). The process was determined to be weakly dependent on temperature, with diffusion playing a significant role in the overall leaching process.
- MakaleAçık Erişim2026Scopus SJRQ2Effects of Magnetic Abrasive Finishing Process Parameters on the Inner Surface Machining of AISI 304 Austenitic Stainless Steel Pipes
Sarıçiçek, İzel; Çaydaş, Alparslan Ulaş; Cihangir, Salih; Say, Yakup
In this study, the effects of SiC abrasive ratio, size of magnetic Fe particles and the machining time parameters on the surface roughness, material removal rate, roundness of the holes and corrosion resistance in magnetic abrasive inner surface finishing (MAF) of the AISI 304 austenitic stainless steel pipes were experimentally investigated. A Taguchi L9 orthogonal array was used for the experiments. The surface roughness and the characteristics of the machined surfaces were examined by using the3D surface topography method. The characteristics of the abrasive and magnetic powders before and after machining operations were investigated under scanning electron microscope (SEM) and x-ray diffraction analysis (XRD) techniques. The electrochemical corrosion measurements were performed in 3.5 wt.% NaCl solutions in a typical three-electrode electrochemical cell. An analysis of variance (ANOVA) method was also applied to the study in order to determine the statistical effects of each factor on the measured responses. Consequently, AISI 304 samples machined with MAF technique revealed better results for corrosion performance, surface quality, material removal rate and the hole dimensional tolerances.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ2Single-Ended Fault Detection and Fault Location in Transmission Lines Using Approximate Derivative
Akdağ, Mustafa; Mamiş, Mehmet Salih; Akmaz, Düzgün
Fault location in power transmission lines (PTLs) relies on impedance or traveling wave (TW) principles. TW approaches offer superior accuracy and high robustness against fault resistance. While multi-ended methods require precise terminal synchronization, single-ended TW (SETW) methods utilize measurements from one terminal, requiring accurate distinction of reflected waves. This study employs the computationally efficient approximate derivative (AD)—the difference between consecutive samples—for SETW fault detection and location. Normally near zero, the AD of modal signals produces sharp transitions during faults. Comparing AD output to a threshold achieves fault detection. The AD then identifies arrival times of the incident and reflected TWs. When using TW theory to distinguish reflections from the fault point and remote end, the fault distance is calculated from their arrival time difference. Validated through 293 diverse ATP simulated fault scenarios, the approach delivered highly accurate results despite using a lower sampling rate than established methods, utilizing an exceptionally short data window—only 2.03 ms for a 300 km line. Finally, operational boundaries for the signal-to-noise ratio (SNR) in noisy conditions are established.
- MakaleAçık Erişim2026Scopus SJRQ1The effect of hydrostatic water level on the local scour downstream of plunging aerated jets
Tunc, Mustafa; Aytac, Ayca; Tuna, M. Cihat; Acar, Ramazan
This paper reports an experimental study on the effect of hydrostatic water level on local scour downstream of plunge aerated jets. To examine the shape of the scour for non-cohesive bed material, different flow and air rates, and different aeration capabilities, hydrostatic water level circumstances were tested. The water jets were aerated using conduit systems with varying cover opening ratios. Measurements were made to determine the length of the scour hole, the value of the maximum scour depth, the location of the maximum scour depth, and the scour hole profile in equilibrium. The current findings show that downstream hydrostatic water levels have a significant impact on the maximum depth and area of scour. Additionally, it was discovered that the conduit gate opening ratio and aeration performance (Qa/Qw) are crucial factors that affect the geometry and diameters of scour holes. The properties of scour caused by various hydrostatic levels were systematically compared to develop empirical correlations for predicting the maximum scour depth. Consequently, predictive emprical formulas incorporating these hydrostatic variations and aeration parameters are presented to improve engineering design accuracy.
- MakaleAçık Erişim2026Scopus SJRQ2The Relationship Between Agricultural Carbon Dioxide Emission and Agriculture Subsectors Production: Static Panel Data Approach
Peker, Ayşe Esra; Akdağ, Nuran; Veysikarani, Dilek; Kaya, Mustafa Göktuğ; Kaya, Perihan Hazel
Human activities contribute to carbon dioxide (CO₂) emissions, which have serious environmental, economic, and social effects of climate change. This has sparked efforts to find large-scale solutions to eliminate the causes of climate change. While these solutions mainly involve reducing carbon emissions through global agreements, individual nations have also taken steps to cut emissions by changing production methods, such as irrigation and fertilisation, to ensure the efficient and effective use of resources and the proper storage and transportation of food. As a result, the agricultural sector is both a source and a victim of this process. The sector’s environmental impact varies due to differing production techniques and energy needs across various sub-sectors like vegetable, grain, and fruit production. Increases in carbon dioxide emissions in this sector are connected not only to production activities but also to demographic and social factors, such as the rural population proportion. This study aims to explore the effect of vegetable, grain, and fruit production, as well as the rural population ratio, on carbon dioxide emissions. To achieve this, a static panel data analysis was conducted across 21 European countries from 1970 to 2023. According to the research findings, vegetable production increases carbon emissions from agriculture. However, it was found to have a significant, albeit borderline, impact on fruit production and to reduce carbon emissions. These results demonstrate that agriculture's contribution to carbon dioxide emissions varies by sub-sector and provide valuable information for developing sustainable agricultural policies.
- MakaleYalnız künye2026Scopus SJRQ1Geochemical signature, detrital zircon U–Pb, and mica Ar–Ar age systematics from the Karadere Basement Unit of the İstanbul-Zonguldak Terrane (NW, Türkiye): evidence for an Avalonian-Cadomian active continental margin
Çimen, Okay; Gücer, Mehmet Ali; Göncüoğlu, Mehmet Cemal; Akal, Cüneyt; Arslan, Mehmet; Simonetti, Antonio; Karaoğlan, Fatih
The İstanbul-Zonguldak Terrane is located in northwest Anatolia and includes several outcrops with pre-Cambrian basement units. The Karadere Basement Unit represents the easternmost basement of this terrane and is composed of paragneiss, quartzite, and orthogneiss. The paragneiss and quartzite are cut by orthogneisses and disconformably overlain by Lower Ordovician to Middle Devonian cover units. Its pre-Cambrian to Palaeozoic tectonic evolution remains poorly understood, and therefore, this study reports whole-rock trace element signatures, detrital zircon U–Pb, and muscovite Ar–Ar age data for samples of paragneiss, quartzite, amphibolite, and orthogneiss. The whole-rock geochemical data indicate that the protoliths of the paragneiss and quartzite samples investigated here could have been derived from arc-related felsic magmatic units located in an active continental margin. The protoliths of amphibolites and orthogneiss samples are gabbro and granite, respectively, and their geochemical signatures are akin to those from continental arc igneous suites. The detrital zircon U–Pb data are characterized by predominantly Mesoproterozoic (84%) and lesser amount of Palaeoproterozoic and Neoproterozoic ages and suggest an early Tonian (youngest peak age of 915 ± 18 Ma) maximum depositional age. Moreover, zircon U–Pb dating analyses from an orthogneiss sample yielded an age of 603 ± 2 Ma, indicating the occurrence of mid-Ediacaran arc magmatism. This represents one of the oldest Ediacaran ages obtained from the metamagmatic basement rocks of the İstanbul-Zonguldak Terrane. Ar–Ar dating of muscovite from ortho- and paragneiss samples yielded ages of 533 ± 25 Ma and 530 ± 9 Ma, respectively, which are interpreted as early Cambrian cooling ages. Overall, the combined results reported here reveal that the Karadere Basement Unit is markedly different from NE African basement units but displays similarities to the basement rocks of both Avalonian and Amazonian terranes. It may have been formed and metamorphosed in an Avalonian–Cadomian active continental margin during the mid- to late Neoproterozoic and early Cambrian.
AtıfScopus1İncele - MakaleAçık Erişim2026Scopus SJRQ3CFD Simulation of Aerodynamic Forces on a Simplified Heavy Vehicle Model with Steady Base Blowing
Firat, Erhan; Seydhan, Mehmet
A numerical investigation was conducted to examine the flow around a European tractor-trailer combination model (GETS) using a steady RANS model k-ω SST at a Reynolds number of 100000. Experimental aerodynamic force measurements were also carried out for the purpose of validating the CFD simulations. The present paper focuses on the effect of steady blowing from the thin slots positioned on the rear surface (base) of the model on the aerodynamic characteristics of the GETS. The combination of three key parameters was tested: the jet-to-freestream velocity ratio (VR), the inclination angle of the jet (θ), and the jet’s location. More than 100 CFD simulations were performed over a range of key parameters. The findings indicate that the jet direction’s inclination towards the rear surface typically leads to a modest yet favorable effect on the drag reduction. It has been demonstrated that increasing the VR to 2 has the potential to reduce aerodynamic drag by up to 50%. However, it is also demonstrated that employing VR values greater than approximately 1.25 is not viable in terms of active flow control efficiency. At θ=0°, the active control efficiency of the both-jets configuration is approximately 6 for VR=0.5 and approximately 1.6 for VR=1. The total drag coefficient on the model is reduced by 8.3% and 17.7% for the VR=0.5 and 1 cases, respectively. It has been demonstrated that the viscous components of total drag and lift are independent of jet configuration, VR, and θ. In both upper and lower jet configurations, it is possible to increase or decrease the aerodynamic lift acting on the model by changing the inclination angle.
- MakaleAçık Erişim2026Scopus SJRQ2Multi-functional GeAg- and TiO2-modified diamond-like carbon thin film device: structure, surface properties, photoresponse, photosensitivity, and biological performance
Aslan, Naim; Şükrü Kurt, Mustafa; Mehmet Koç, Mümin; Yilmazer, Yasemin; Coskun, Burhan; Aksakal, Bünyamin
DLC films represent a promising class of materials that can be used in various applications due to their optical, optoelectronic, tribological, and biomedical characteristics. In this work, GeAg- and TiO2-modified DLC thin films were prepared using the magnetron sputtering method under ultrahigh vacuum conditions. DLC thin film characteristics and addition of GeAg and TiO2 into the DLC structure were confirmed and subsequently assessed via scanning electron microscopy (SEM), atomic force microscopy, energy dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, and Raman spectroscopy. DLC thin film thicknesses were determined via SEM and found to be 235 nm and 380 nm for DLC/TiO2 and DLC/GeAg thin films, respectively. Contact angle and surface wettability analyses were performed for uncoated glass, GeAg- and TiO2-modified DLC thin films. The antibacterial properties of the DLC films were assessed for E. coli and S. aureus. The biocompatibility of these same films was confirmed using the L929 cell line, where no toxic effect was evidenced. To elucidate the optical characteristics of the thin films, a UV–vis spectrum was obtained, and band gap energies were proposed using these data. Photoresponse characteristics of the DLC thin films were assessed under varying illumination using current–time plots. It could be seen that DLC thin films’ responsiveness to light was dependent on illumination intensity. The results demonstrate that nanostructures are good candidates for multifunctional applications exhibiting good antibacterial and photoresponsive characteristics with outstanding biocompatibility.
- MakaleAçık Erişim2026Scopus SJRQ3Functional magnetic polymer nanocomposites: Fe2O3/Fe3O4-enhanced PCL-PVA materials
Deniz Çirak, Zehra; Aydin, Handan; Coşkun, Meltem; Kök, Mediha
In this study, magnetic polymer nanocomposites based on PCL/PVA PCL(Polycaprolactone)-PVA(Polyvinyl alcohol) (80/20) reinforced with Fe2O3 and Fe3O4 nanoparticles were successfully produced, and their thermal, structural, morphological, and magnetic properties were comparatively investigated. The systematic evaluation of the effects of Fe2O3 and Fe3O4 additions on the same biodegradable polymer matrix at 20% and 40% loading levels constitutes the main novelty of this study. The nanocomposites were characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and physical property measurement system (PPMS) analyses. The TGA results demonstrated that the decomposition onset temperature increased with the addition of nanoparticles and, particularly in the composite with 40% Fe3O4 content, the residual mass reached 15.81%, indicating a significant improvement in thermal stability. DSC analyses showed that the melting peak temperature increased at high loading levels and that Fe2O3 loading supported crystallization more than Fe3O4. FTIR and XRD results confirmed that the nanoparticles dispersed successfully in the polymer matrix without forming chemical bonds and provided strong interfacial interactions. The SEM images revealed a homogeneous distribution at low loading levels, while significant agglomeration formed at high Fe3O4 content. Magnetic measurements indicated that the pure PCL/PVA blend exhibited diamagnetic behavior, Fe2O3-containing composites displayed hard ferromagnetic behavior, and Fe3O4-containing composites exhibited soft ferromagnetic behavior. The highest saturation magnetization of 10.4 emu/g was obtained in the composite with 40% Fe3O4 content. The findings indicate that Fe2O3- and Fe3O4-doped PCL/PVA nanocomposites are functional materials with high potential for applications in sensors, actuators, magnetically controlled systems, and biomedical applications.
- MakaleYalnız künye2026Scopus SJRQ1Engineering Ti-Zr-Hf high-entropy alloys (HEA) with rare-earth and boron additives for microstructure-controlled mixed-field radiation shielding: Fabrication, physical, structural and experimental γ-ray & fast-n shielding properties
Özkul, İskender; Güler, Ömer; Kavaz, E.; Kalay, Ece; Güler, Seval Hale; ALMisned, Ghada; Tekin, H.O.
This study investigates three newly designed Ti-Zr-Hf-based high-entropy alloys such as TiZrHfGdSm (N1), TiZrHfEr (N2), and TiZrHfGdEuB (N3), with the aim of understanding how selected rare-earth and boron additions influence microstructural evolution and dual γ-ray/fast-neutron shielding performance. All alloys were synthesized by arc melting and evaluated through thermodynamic modelling, X-ray diffraction, scanning electron microscopy with elemental mapping, and mixed-field attenuation measurements. The results show that each composition forms an HCP-type solid-solution matrix with composition-dependent lattice distortion and secondary phase formation. Among the studied systems, the Er-modified alloy N2 develops the most spatially uniform elemental distribution and demonstrates the most balanced combination of γ-ray attenuation, effective atomic number, buildup behaviour, and fast-neutron removal efficiency. N1 and N3, containing multiple rare-earth elements and, in the case of N3, boron-induced borides, exhibit distinct grain features and provide valuable insights into how multi-element additions shape photon and neutron interaction pathways. Comparative examination confirms that shielding performance in these HEAs is governed by the interplay of elemental cross sections, density, and microstructural uniformity. The findings highlight Ti-Zr-Hf-RE(B) alloys as promising platforms for multifunctional radiation-shielding materials and provide a compositional framework for future optimization in nuclear, medical, and aerospace applications.
AtıfScopus2OpenAlex2İncele - MakaleAçık Erişim2026Scopus SJRQ1Preparation of Nanographene-Based Copolymer Nanocomposites: Thermal Decomposition Kinetic, Optical, and Electrical Behaviors
Barim, Esra; Demirelli, Kadir
The poly(4-methacryloyloxyphenyl-4'-methoxystyryl ketone-co-methyl methacrylate) [P(MPMESK0.25-co-MMA)] was synthesized using a free radical copolymerization method at 60 °C. The composition of the copolymer was estimated by 1H-NMR. The nanocomposites of P(MPMESK0.25-co-MMA)-loaded 9 and 11 wt% nanographene (NG) were produced using the ultrasonic homogenizer sonicator. The FT-IR, 1H-NMR, GPC, TGA, XRD, and SEM techniques were used to characterize the copolymer and composites. The thermal behavior of P(MPMESK0.25-co-MMA) partially heated up to 270, 310, 340, and 380 °C was investigated by FT-IR analysis. A six-membered anhydride ring in the copolymer backbone formed at 340 °C and higher temperatures. TG measurements were used to analyze the thermal decomposition processes of pure P(MPMESK0.25-co-MMA) and P(MPMESK0.25-co-MMA)/NG 11 wt% composite. Apparent activation energies for thermal decomposition of P(MPMESK0.25-co-MMA)/NG 11 wt% were determined using the Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods at a temperature range of 200 and 400 °C for a weight loss of approximately 70%. The average activation energies determined from the FWO and KAS methods were 86.3 and 80.3 kJ/mol, respectively. The dielectric and electrical behaviors of the P(MPMESK0.25-co-MMA) and P(MPMESK0.25-co-MMA)/NG 11 wt% composite were investigated at room temperature. The dc activation energy for dc conductivity of nanocomposite was calculated as 1.092 eV. Optical properties such as absorption, reflectance, refractive index, absorption edge, direct band gap of the copolymer, and composites were investigated from their optical examinations in the wavelength region of 200–800 nm. It was found that the optical energy gap values had shifted to the lower energies with the doping of NG.
AtıfScopus1OpenAlex1İncele - MakaleYalnız künye2026Scopus SJRQ2Drying temperature-dependent changes in grape seed bioactives and oxidative status: integrated HPLC/GC and multivariate analysis
Karaca Sanyürek, Nesrin
Abstract: Drying temperature (40–80 °C) critically influences the stability of bioactive compounds in grape seeds and their functional responses. In this study, we evaluated the vitamin and phytosterol content of Boğazkere grape seeds using high-performance liquid chromatography (HPLC) and the fatty acid content using gas chromatography (GC). Antioxidant capacity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and the oxidative stress marker, malondialdehyde (MDA). Temperature-dependent and compound-specific alterations were observed: while selected vitamins and phytosterols showed distinct thermal susceptibilities, fatty acid profiles exhibited measurable remodeling. Antioxidant activity revealed non-linear dose- and temperature-dependent patterns, whereas MDA consistently decreased with increasing temperature, reflecting the reduced oxidative metabolism in dehydrated tissues. Multivariate analysis, including principal component analysis (PCA) and heatmap visualization, effectively discriminated temperature treatments and revealed correlations between compositional and functional parameters. The combined use of univariate and multivariate analyses revealed that the drying temperature reshaped not only individual bioactive compounds but also the overall biochemical profile of grape seeds. These findings establish a mechanistic link between thermal processing and bioactive stability, providing a chemical basis for optimizing grape seed valorization in food systems.
- MakaleAçık Erişim2026Scopus SJRQ1Modulation of SIRT1/PPARγ pathways and tight junction proteins by nicotinamide riboside under chronic variable stress
Celik, Abdullah; Sahin, Nurhan; Orhan, Cemal; Er, Besir; Erten, Fusun; Ozmen, Busra; Tuzcu, Mehmet; Ozercan, Ibrahim Hanifi; Sahin, Kazim
Abstract: Chronic stress disrupts homeostasis, leading to major health problems such as liver damage, intestinal barrier dysfunction, and impaired glucose metabolism. Although current treatments, including anxiolytics, sedatives, antidepressants, and beta blockers, are effective, their adverse effects emphasize the need for safer alternatives. Nicotinamide riboside (NR), a precursor of nicotinamide adenine dinucleotide (NAD+), plays a central role in energy metabolism and oxidative stress regulation; elevated NAD + levels have been associated with reduced risk of chronic diseases such as obesity and type 2 diabetes. However, the effects of NR on liver metabolism, intestinal barrier integrity, and related protein pathways remain unclear. This study investigated the effects of NR supplementation in rats exposed to chronic variable stress (CVS). Fifty-six male Sprague Dawley rats were divided into normal and CVS groups and treated in a 2 × 4 factorial design with 0, 150, 300, or 600 mg/kg NR. Under CVS conditions, serum glucose, corticosterone, ACTH, and insulin levels increased, whereas NAD+, NADPH, nicotinamide (NAM), and nicotinic acid (NA) decreased significantly (p < 0.001). NR supplementation effectively corrected these biochemical imbalances and upregulated hepatic markers, including PPARγ, SIRT1, GLUT2, IRS1, and FASN (p < 0.001). Furthermore, the increased expression of key transport proteins such as PepT1, LAT2, EAAT3, FABP2, and FATP4 contributed to maintaining intestinal barrier integrity and improving gut health. NR also promoted the recovery of tight and adherens junction proteins. Notably, high-dose NR (600 mg/kg) markedly alleviated liver fibrosis, improved glucose metabolism, and strengthened intestinal barrier function, demonstrating its therapeutic potential as an alternative strategy against stress-induced metabolic disorders. Key points: • NR mitigated chronic stress-induced liver, intestinal, and glucose dysregulation. • NR improved glycemia and NAD⁺-related biomarkers under stress. • NR reduced hepatic fibrosis markers. • NR strengthened TJ/AJ proteins, supporting intestinal barrier integrity. • Findings support NR’s therapeutic potential in stress-related metabolism.
- MakaleYalnız künye2026Scopus SJRQ1Psychological well-being and aggression in handball players: examining the mediating role of exercise addiction
Güler, Muhammed; Yeşiltepe, Akgün; Topcuoğlu, Ceyhun
Objective: This study aimed to examine the relationship between psychological well-being and aggression among handball players and to determine whether exercise addiction mediates this relationship. Methods: A descriptive, cross-sectional, and correlational design was used. The population consisted of players competing in the Turkish Handball Leagues during the 2024–2025 season, and 442 athletes participated using a non-probability sampling method. Data were collected via an online survey including a personal information form, the Psychological Well-Being Scale, the Buss–Perry Aggression Questionnaire, and the Exercise Addiction Inventory. Results: Psychological well-being showed a significant negative correlation with aggression (r = −0.242, p < 0.001). Exercise addiction was positively associated with both psychological well-being (r = 0.212, p < 0.001) and aggression (r = 0.105, p = 0.027). Mediation analysis indicated that exercise addiction significantly and partially mediated the relationship between psychological well-being and aggression (indirect effect 95% CI: 0.0246–0.1654). The direct effect of psychological well-being on aggression remained significant (β = −0.7093, p < 0.001). Conclusion: Higher psychological well-being was associated with lower aggression among handball players, whereas exercise addiction was associated with both higher psychological well-being and higher aggression and emerged as a partial statistical mediator of this relationship. These findings may help inform future studies and preventive strategies focusing on athlete mental health and behavioral regulation. However, because of the cross-sectional design, causal inferences cannot be drawn.
- MakaleAçık Erişim2026Scopus SJRQ4Petrography, geochemistry and formation of the Sarıçimen (Van, eastern Türkiye) Fe-Ni-Co laterite deposit
Çimen, Okay
The Sarıçimen Fe-Ni laterite deposit is located in eastern Türkiye (Van province) and represents one of the important Ni and Co-enriched lateritic mineralizations formed in the ophiolitic occurences. This study aims to decipher the petrographic and geochemical signatures of the laterite horizon in order to better figure out the processes controlling Fe-Ni-Co mineralization and the genesis of the deposit. In this study, field and petrographic observations, and whole-rock geochemical data have been used to characterize the mineralogical and geochemical evolution of the lateritic horizon. Petrographic studies indicate that the protolith of the laterite zone is mostly composed of serpentinized ultramafic rocks including relics of Cr-spinel and chromite grains. This lateritic zone is characterized by hematite-and magnetite-rich zones formed above saprolitic levels that may have been derived from the weathering of ultramafic parent rocks. Whole rock geochemical analyses indicate that Fe₂O₃ and SiO₂ are the dominant oxides, and Ni concentrations vary between 0.33 and 1.01 wt.%. Also, Co values are ranging between 330 ppm and 600 ppm in the laterite samples investigated here. More importantly, correlation analyses exhibit a positive relationship between Ni and Fe₂O₃ and this may be attributed to a close association with Fe-oxide minerals during the lateritization. In contrast, a negative correlation between Ni and SiO₂ may indicate the presence of silica depletion during chemical weathering. The geochemical trends investigated here reveal that the laterite zone developed through intense lateritic weathering of ultramafic rocks, which is characterized by the removal of relatively mobile elements such as Si and Ca and the residual enrichment of Fe, Ni, and Co. The presence of Cr-spinel relics once again confirms the ultramafic origin of the parental rocks. Overall, the Sarıçimen deposit represents a Fe-Ni-Co laterite derived from nearby ultramafic sources within the ophiolitic sequence. The occurrence of Fe-Ni-Co laterite deposits at both the southwestern and northeastern segments of the Southern Neotethys Suture Zone suggests that this tectonic belt may represent a promising metallogenic area for lateritic Fe-Ni-Co mineralization in the southern Türkiye.
- MakaleYalnız künye2026Scopus SJRQ2An Innovative Thermal Management Approach Enhanced by Thermoelectric Stations and Turbulators for Lithium-Ion Batteries
Tuğan, Volkan; Yardımcı, Uğurcan
The design of an effective battery thermal management system is critical to ensure the safe, efficient, and long-lasting operation of lithium-ion batteries. Excessive heat generation and temperature non-uniformity among cells in high energy density battery systems lead to performance degradation, accelerated aging, and an increased risk of thermal runaway. Although liquid-cooled systems and thermoelectric module-assisted solutions have been extensively investigated separately in the literature, studies that holistically evaluate multiple thermoelectric stations combined with an innovative flow channel design and turbulator integration remain limited. This gap constitutes a significant research need, particularly in terms of improving temperature uniformity and reducing maximum cell temperature. In this study, to address this research gap, a novel liquid-cooled battery thermal management system integrating thermoelectric coolers and turbulators within the flow channel is proposed. The thermal performance of the proposed system was systematically analyzed using computational fluid dynamics under three different configurations (conventional system, thermoelectric-assisted system, and turbulator-integrated thermoelectric-assisted system) and four different mass flow rates (0.0008, 0.0013, 0.0018, and 0.0023 kg/s). The results indicate that, at a mass flow rate of 0.0023 kg/s, the integration of thermoelectric coolers and turbulators reduces the maximum battery temperature by 8.95 K and the maximum temperature difference by 6.83 K. At the highest mass flow rate, the proposed system achieves a maximum battery temperature of 306 K and a maximum temperature difference of 4.5 K, ensuring both effective cooling performance and high temperature uniformity. Overall, the results in terms of cooling performance and temperature uniformity demonstrate that the combination of thermoelectric modules and turbulators offers significant potential for advanced battery thermal management system applications and offers an effective solution for high-energy-density systems.