Hakkari Üniversitesi Akademik Veri Yönetim Sistemi
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İdrar Örneklerinden İzole Edilen Escherichia coli Suşlarında Antibiyotik Direnci: Klinik ve Demografik Faktörlerin Etkisi
No full textTiming Matters, Not Just the Treatment: Phenological-Stage-Specific Effects of Seaweed and Ethanol Applications on Postharvest Quality of ‘Tarsus Beyazı’ Grapes
No full textIn the context of increasing consumer demand for high-quality, residue-free fruits and the growing emphasis on sustainable postharvest technologies, identifying effective, eco-friendly treatments to maintain grape quality during storage has become a critical focus in modern viticulture. Over the course of this study, we examined the influence of seaweed extract (derived from Ascophyllum nodosum) and ethanol-based postharvest treatments on the postharvest quality of the ‘Tarsus Beyazı’ grape. The seaweed extract was applied at six specific phenological stages according to the BBCH scale: BBCH 13 (3rd–4th leaf stage, 0.40%), BBCH 60 (first flower sheath opening, 0.50%), BBCH 71 (fruit set, 0.50%), BBCH 75 (chickpea-sized berries, 0.50%), BBCH 81 (start of ripening, 0.60%), and BBCH 89 (harvest maturity, 0.60%). After harvest, grape clusters were subjected to four different postharvest treatments: untreated control, control + ethanol (20% ethanol immersion for 10 s), seaweed extract alone (preharvest applications only), and seaweed extract + ethanol (combining both preharvest and postharvest treatments). Grapes were stored at 0–1 °C and 90–95% RH for three weeks, followed by a shelf-life evaluation period of three days at 20 °C and 60–65% RH. The findings revealed that seaweed treatments, especially when applied during cluster formation and berry development, effectively mitigated physiological deterioration, preserving stem turgidity and enhancing berry firmness. In contrast, ethanol showed variable responses, occasionally exerting negative effects, with only marginal benefits observed when applied at optimal developmental stages. Both the type and timing of application emerged as critical determinants of key quality attributes such as weight loss, decay incidence, and must properties (TSS, pH, TA). Correlation and heat map analyses indicated the interrelationships among these parameters and the differential impacts of treatments. These results suggest that phenological-stage-specific seaweed applications hold significant potential as a sustainable strategy to extend the storage life and maintain the market quality of ‘Tarsus Beyazı’ grapes
Frame-dragging and light deflection in rotating optical wormhole spacetimes
No full textIn this work, we present a detailed analytical study of null geodesics in a family of rotating optical wormhole spacetimes with constant negative Gaussian curvature, encompassing hyperbolic, elliptic, and Beltrami geometries. By explicitly deriving the full set of null geodesic equations, we characterize photon trajectories in these curved, rotating backgrounds. Our analysis highlights the role of rotation in shaping light paths, showing how frame-dragging effects, ergoregion emergence (despite the absence of event horizons), and alterations in causal structure influence photon dynamics. We construct exact forms of the effective potential governing radial photon motion, allowing for a systematic investigation of orbit stability and critical trajectories. Closed-form expressions for gravitational deflection angles are obtained, along with clear conditions for the presence and positioning of optical horizons unique to these geometries. Our findings demonstrate that the interplay between rotational effects and the geometry-specific radial shape functions crucially determines how light behaves in these exotic spacetimes. While some features echo those of analog gravity models, our framework remains strictly within general relativity. This study provides a rigorous foundation for understanding gravitational lensing and horizon behavior in spacetimes with nontrivial topology</p
Evaluation of Rheological and Functional Properties of Kefiran Biopolymer Isolated from Kefir Grains
No full textThe increasing demand for biopolymers in the food industry has increased interest in using alternative resources. Kefiran, which is produced by microorganisms found in kefir grains, is a versatile exopolysaccharide (EPS) that can form gel, an important biopolymer for the food manufacturing. In this study, kefiran extracted by using an EPS isolation method was characterized by rheological analysis according to power law model and determination of functional properties and texture profile analysis. The effects on apparent viscosity (ηa) and flow properties of kefiran concentrations ranging from 1.1 to 3.1% (w/v) were investigated. The results indicated that kefiran solutions at low concentrations exhibited behavior close to Newtonian, whereas at higher concentrations, they showed pseudoplastic (shear-thinning) behavior. This shear-thinning behavior is attributed to hydrogen bonding between hydroxyl groups and water molecules, which contributes to the formation of an entangled polymer network. The results showed that isolated kefiran at a high degree of purity (93.0%) was able to possess good texture profile properties and with a high degree of water holding capacity (WHC) (90.3%), and bloom strength value (53.0 g). Kefiran had a gelling temperature of 14 °C. This study confirms that extracted polysaccharide can be especially used as a gelling agent in fermented dairy products and can also be successfully used as a texture improver biopolymer in food systems
TÜRKİYE YÜZYILI MAARİF MODELİ’NİN SÜRDÜRÜLEBİLİR KALKINMA AMAÇLARINDAN NİTELİKLİ EĞİTİM İLE UYUMU
No full textInvestigation of the therapeutic effect of melatonin on deltamethrin applied mouse primary hepatocyte culture
No full textObjective: In recent years, it has been known that the melatonin hormone, secreted from the pineal gland, possesses significant antioxidant activity. This study explores the therapeutic effect of melatonin on the deleterious effects of deltamethrin, a pyrethroid pesticide extensively used worldwide, including in Türkiye, on mouse liver cells. Methods: Hepatocytes from Balb/C mice were isolated using a two-stage perfusion method, resulting in over 85% live hepatocytes. The isolated cells were cultured with different doses of deltamethrin (1 and 10 µM) and melatonin (100 µM) for 24 and 48 hours. At the conclusion of the culture period, hepatocytes were extracted at the 24th and 48th hours, and Malondialdehyde (MDA), Total Antioxidant Capacity (TAC), Total Oxidation Status (TOS), and DNA damages (8-hydroxy-2’-deoxyguanosine (8-OHdG)) were examined. Results: While an increase in MDA, TOS, and DNA damage was observed in the deltamethrin-administered groups of hepatocytes, a decrease in TAC level was noted. It was determined that the applied deltamethrin had no effect on cell viability throughout the application period. Conclusion: Furthermore, it was observed that melatonin, when administered concurrently with deltamethrin, reduced the toxic effect of deltamethrin. This study suggests that melatonin has a protective effect against deltamethrin-induced damage in mouse hepatocyte cells
