https://hdl.handle.net/11436/887 2026-09-25T01:51:17Z 2026-09-25T01:51:17Z Öğretmen, Özen Yusuf Karslı, Barış Emanet, Muhammet https://hdl.handle.net/11436/11026 2025-08-26T12:41:04Z 2025-01-01T00:00:00Z

Metal(oid) bioaccumulation, Se[sbnd]Hg balance, and human health risk assessment in anchovy (Engraulis encrasicolus) from the southern Black Sea Öğretmen, Özen Yusuf; Karslı, Barış; Emanet, Muhammet The European anchovy (Engraulis encrasicolus) is the widely caught fish species in Türkiye, both in terms of catch volume and widespread consumption. It holds significant economic and cultural value, particularly in the Black Sea region, where it is a staple in local diets. This study aimed to assess toxic element contamination in anchovies and evaluate potential human health risks. Metal(oid) levels were analyzed in samples collected monthly over a one-year period from the southeastern Black Sea. Although concentrations varied monthly, they remained below national and international safety limits. Seasonal variations in the concentration of 15 metal(oid)s were statistically insignificant. Health risk assessments, including estimated weekly intake (EWI), target hazard quotients (THQ), and hazard index (HI), revealed no adverse effects from regular consumption. The study also noted low mercury (Hg) levels, with a selenium (Se) to mercury molar ratio above 1 during all seasons, suggesting that selenium may mitigate the toxic effects of mercury. Thus, consuming anchovies presents a favorable risk/benefit balance for health. Carcinogenic risk index (CRI) values for arsenic (As), lead (Pb), and chromium (Cr) were within acceptable thresholds. These results demonstrate that anchovies from the region are safe to eat and pose no significant health risk. Importantly, this is the first study to investigate monthly and seasonal variations in metal levels in European anchovies from the Black Sea. The findings contribute valuable data for public health assessments and support the need for continued monitoring to address environmental changes and maintain seafood safety.

2025-01-01T00:00:00Z Öner, Erdal Oktay, Mine Gül Yaylacı, Ecren Uzun Yaylacı, Murat Mirzaloğlu, İrem https://hdl.handle.net/11436/10921 2025-08-15T08:36:47Z 2025-01-01T00:00:00Z

Tri-method analysis of contact mechanics in orthotropic-isotropic materials Öner, Erdal; Oktay, Mine Gül; Yaylacı, Ecren Uzun; Yaylacı, Murat; Mirzaloğlu, İrem This study examines the contact mechanics of a homogeneous orthotropic layer resting on a homogeneous isotropic half-space without being bonded, subjected to loading by a rigid cylindrical punch. The effect of the orthotropic layer’s body force has been taken into account in the study. The study is conducted in three phases. In the first phase, the contact problem is analytically tackled using advanced methods such as elasticity theory, integral transform techniques, and Gauss–Chebyshev integration. The second phase utilizes finite element analysis through ANSYS software, accurately modeling the system. In the final phase, an artificial neural network is employed, allowing the system to learn and recognize intricate patterns in the data. The standout feature of this study is its thorough comparison of these three distinct methodologies, offering a comprehensive understanding of the contact mechanics between isotropic and orthotropic materials. The results reveal key insights into contact length, maximum contact stress, critical separation load, and separation distance, all as functions of critical dimensionless parameters. This study is significant in today’s advancing field of contact mechanics as it not only explores the combined impact of body forces and the interaction between orthotropic and isotropic materials but also uniquely compares the results using three distinct methods, offering comprehensive insights that address both theoretical and practical challenges.

2025-01-01T00:00:00Z Yaylacı, Ecren Uzun Öztürk, Şevval Kara, Ayşe Yaylacı, Murat Çağlak, Emre https://hdl.handle.net/11436/10905 2025-08-14T10:20:08Z 2025-01-01T00:00:00Z

Microbial calcite precipitation by marine-derived rhodococcus strain RK-15: characterization and application in concrete Yaylacı, Ecren Uzun; Öztürk, Şevval; Kara, Ayşe; Yaylacı, Murat; Çağlak, Emre This study investigates the impact of ureolytic bacteria isolated from sea surface water on the compressive strength and water absorption characteristics of concrete. In this context, the strain RK-15 was selected in the preliminary screening with Stuart’s broth and used in further experiments. Phylogenetic analysis of the 16S rRNA gene sequence identified the isolate as Rhodococcus erythropolis. This strain demonstrated the highest urease activity on the 5th day at 30 °C and pH 8. The isolate accumulated spherical crystals in a solid Urea-CaCl2 medium. Energy-dispersive X-ray spectroscopy (EDS) analysis revealed the presence of calcium, carbon, and oxygen in the precipitated minerals. In concrete production, 0.5% of the cement weight (2 × 109 cells/ml) bacterial culture was used. Compressive strength and water absorption measurements were performed on the 3rd, 7th, and 28th days. Results showed that the addition of Rhodococcus strain RK-15 led to a 13.61% increase in compressive strength and a 23.33% reduction in water absorption by weight compared to the control group. These findings suggest that the addition of strain RK-15 offers a sustainable and environmentally friendly method to enhance the mechanical and physical properties of concrete.

2025-01-01T00:00:00Z Seyhan, Kadir Dürrani, Ömerhan Papadaki, Lydia Akinsete, Ebun Atasaral, Şebnem Özşeker, Koray Akpınar, Hatice Kurtuluş, Ercan Mazlum, Rahşan Evren Koundouri, Phoebe Stanica, Adrian https://hdl.handle.net/11436/10893 2025-08-14T06:17:42Z 2025-01-01T00:00:00Z

Bridging the gaps for a thriving Black Sea Blue Economy: insights from a multi-sectoral forum of Turkish stakeholders Seyhan, Kadir; Dürrani, Ömerhan; Papadaki, Lydia; Akinsete, Ebun; Atasaral, Şebnem; Özşeker, Koray; Akpınar, Hatice; Kurtuluş, Ercan; Mazlum, Rahşan Evren; Koundouri, Phoebe; Stanica, Adrian The Black Sea ecosystem faces significant challenges due to climate change and human activities. Despite this, the opportunities and potential of its Blue Economy and the role of Turkish stakeholders in the key sectors have not been well documented. To define the needs of the Black Sea's Blue Economy and outline existing problems, a workshop entitled "Engaging Stakeholders: Trabzon Multi-Actor Forum" was held in Trabzon (T & uuml;rkiye) in November 2022. Stakeholders from the research sector, academia, civil society, industry, business, competent authorities, and government shared their thoughts on various sectors of the Blue Economy, covering 17 areas. They discussed political, environmental, social, technical, legal, and economic aspects, revealing opportunities, challenges, and areas where more research is needed. This meeting provided valuable insights, indicating that efficient collaboration with stakeholders could lead to effective solutions and strategies, helping to improve the Blue Economy in the Black Sea region.

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