Browsing by Author "Yildiz, Mehmet"

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Age-Specific Analysis of Anti-Müllerian Hormone and Liver Biochemical Parameters in Freemartin Holstein Calves and Heifers: a Pilot Study
(Elsevier Science inc, 2024) Bozkurt, Gokhan; Kaya, Feyyaz; Yildiz, Mehmet; Sengul, Sultan; Kocaer, Ismail Ilker; Saribas, Halil Erkan; Koker, Afsin
Freemartinism is the most common congenital anomaly among sexual disorders in dairy cows. This syndrome typically occurs in different -sex twin pregnancies and causes vascular anastomoses to form with the placenta in the early stages of fetal development. The study aims to determine the effectiveness of Anti-m & uuml;llerian hormone (AMH) levels in calves and heifers of different age groups for diagnostic factors and to investigate the potential consequences of different hormone levels in different age groups on some liver biochemical parameters. The study involved 50 cattle from diverse age categories, divided into the freemartin group (FM Group, n =25) and the control group (C Group, n =25). Both FM and control groups were further divided into early -age (3-5 months), middle-aged (5-9 months), and older -aged groups (9-12 months). Serum AMH levels, along with total protein, albumin, and total cholesterol levels, were measured. While no statistically significant difference in AMH levels was observed in the early -age group (P:0.53), significant differences were determined in the middle (P:0.015) and older -age groups (P:0.01), where the FM group exhibited significantly decreased AMH levels compared to the control group. The evaluation of liver biochemistry revealed a statistically significant difference in total protein levels between the FM and control groups in the older age group (P:0.033). Consequently, it is reasonable to suggest that AMH levels may serve as a valid parameter for diagnosing freemartin syndrome in calves aged older than five months. Conversely, particularly in young calves, no significant differences in liver functionality were observed between freemartin-affected and healthy calves.
The Effect of L-Carnitine Supplementation in Culture Medium on the Development and Cryopreservation of in Vitro Produced Bovine Embryos
(Wiley, 2025) Yildiz, Mehmet; Cetin, Yunus
Background: In vitro culture media play a crucial role in supporting the growth and development of bovine embryos. Despite advancements in media formulations, there is ongoing interest in optimising these media by supplementing them with compounds like L-carnitine to improve embryo development and cryopreservation outcomes. However, the effects of L-carnitine supplementation in commercial culture media remain unclear. The aim of this study was to investigate the effects of adding 0.75 mM L-carnitine to commercial in vitro culture (IVC) media on bovine in vitro embryo production (IVP). The first phase of the study evaluated the effects of L-carnitine on embryo development, while the second phase evaluated the effects of L-carnitine on embryo cryopreservation. Methods: A total of 508 bovine ovaries used in the study were harvested from slaughterhouses. Only morphologically healthy ovaries were included in the study, while ovaries with cysts or any pathological findings were excluded. Oocytes were collected by aspiration method. The collected oocytes were fertilised in vitro using prepared spermatozoa under standard conditions. Following fertilisation, embryos were morphologically evaluated, and only those exhibiting uniform blastomeres and minimal cytoplasmic fragmentation were included in subsequent steps. The embryos were then randomly divided into two groups: one supplemented with 0.75 mM L-carnitine in the IVC medium and the other without supplementation. Cleavage rates on Day 4 and embryo development rates on 7 days after fertilisation were evaluated with the supplementation of L-carnitine. In addition, the survival effects of embryos collected on Day 7 after direct culture, slow freezing and vitrification were investigated. Results: It was determined that L-carnitine supplementation to IVC medium did not affect the cleavage rates on Day 4 and blastocyst development rates on Day 7 (p > 0.05). Moreover, it did not affect the survival and development rates of embryos collected on Day 7 following both slow freezing and thawing, as well as vitrification and warming processes (p > 0.05). Conclusions: Supplementation of L-carnitine to commercially available in vitro culture medium did not enhance embryo development rates or survival rates after cryopreservation. This is likely due to the presence of antioxidant compounds in commercial embryo culture media.
Effect of Serum Anti-Müllerian Hormone Levels on the Superovulation Response in Holstein Heifers
(Wiley, 2024) Yildiz, Mehmet; Bastan, Ilktan; Guler, Sohret; Cetin, Yunus
Background: Anti-M & uuml;llerian hormone (AMH) holds potential as a biomarker for assessing the superovulation (SO) response in cattle. Nonetheless, there exists scant information regarding this aspect in the literature concerning dairy heifers. Given this gap, our objective is to explore the viability of AMH as an indicator for gauging the SO response specifically in Holstein heifers. Furthermore, our aim encompasses examining the variations in AMH levels within the same individuals before and after undergoing SO. Methods: The study included 41 Holstein heifers. All heifers were superovulated and blood samples were taken both before and after the SO protocol. Results: The findings revealed that the mean values of serum AMH concentrations before and after SO were 0.122 ng/mL (0.093-0.248 ng/mL) and 0.119 ng/mL (0.084-0.170 ng/mL), respectively. AMH concentrations in heifers were stratified into low (<0.106 ng/mL), medium (0.107-0.126 ng/mL) and high (>0.127 ng/mL) categories both before and after SO. Conclusions: There was no significant correlation between AMH levels in the heifers both before and after SO treatment with the number of follicles, corpora lutea, total embryos collected or embryos transferred (p > 0.05). Furthermore, this study showed that serum AMH concentrations in Holstein heifers did not change after SO treatment. In this study, as AMH levels in Holstein heifers were in a narrow range, a relationship between AMH and SO response could not be determined. In future studies, we believe that it would be more useful to plan more studies in Holstein donor heifers, taking into account the number of animals and AMH levels.
An Evaluation of the Instruction Carried Out With Printed Laboratory Materials Designed in Accordance With 5e Model: Reflection of Light and Image on a Plane Mirror
(Modestum Ltd, 2015) Ayvaci, Hakan Sevki; Yildiz, Mehmet; Bakirci, Hasan
This study employed a print laboratory material based on 5E model of constructivist learning approach to teach reflection of light and Image on a Plane Mirror. The effect of the instruction which conducted with the designed print laboratory material on academic achievements of prospective science and technology teachers and their attitudes towards physics laboratory was questioned. The study was carried out with 98 prospective teachers who attended the course named General Physics Laboratory III and undergraduate students at the Department of Science Education at Karadeniz Technical University during 2011-2012 fall semesters. The study was conducted by adopting semi-experimental method. Experimental group instructed with the designed print laboratory material whereas control group instructed in through traditional laboratory practices. The Achievement Test, Physics Laboratory Attitude Scale, and Reflective Writings were used as data collection tools. It was proved that the instruction carried out with print laboratory materials based on 5E model contributed to academic achievements of prospective teachers and their attitudes towards physics laboratory more than the instruction based on traditional approach. Based on the research results, it was recommended that print materials prepared based on the constructivist learning theory could be generalized in the Physics Laboratory courses.
Lipid Peroxidation and Dna Oxidation Caused by Dental Filling Materials
(Elsevier Taiwan, 2017) Yildiz, Mehmet; Alp, Hamit Hakan; Gul, Pinar; Bakan, Nuri; Ozcan, Mutlu
Background/purpose: The two direct dental restorative materials most commonly used today are silver-mercury amalgam and resin-based composites. The purpose of this study was to examine the effects of these two restorative materials and substances released by these into the oral environment on lipid peroxidation and DNA oxidation after entering the blood circulation. Materials and methods: Blood samples from 41 patients were collected before and 24 hours after the application of these restorative materials. The 8-hydroxydeoxyguanosine/deoxyguanosine ratio in these samples was measured to determine oxidative DNA damage, and malondialdehyde levels were measured to define lipid peroxidation. The paired samples t test and Pearson correlation analysis were used for the analysis of variables (alpha = 0.05). Results: While no statistically significant difference was observed after amalgam filling application in terms of DNA oxidation, a significant difference was observed after composite application (P < 0.05). Furthermore, a significant increase was determined in malondialdehyde levels of two materials (P < 0.05). In both amalgam and composite applications, a significant difference was observed before and after application in terms of released substances (mercury and unpolymerized monomer, respectively, P < 0.001). Conclusion: Mercury increased lipid peroxidation and Bis-GMA and TEGDMA dental resins increased both lipid peroxidation and DNA oxidation markers. (C) 2017 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.
Segmentation and Classification of Skin Burn Images With Artificial Intelligence: Development of a Mobile Application
(Elsevier Sci Ltd, 2024) Yildiz, Metin; Sarpdagi, Yakup; Okuyar, Mehmet; Yildiz, Mehmet; Ciftci, Necmettin; Elkoca, Ayse; Bingol, Buenyamin
Aim: This study was conducted to determine the segmentation, classification, object detection, and accuracy of skin burn images using artificial intelligence and a mobile application. With this study, individuals were able to determine the degree of burns and see how to intervene through the mobile application. Methods: This research was conducted between 26.10.2021-01.09.2023. In this study, the dataset was handled in two stages. In the first stage, the open -access dataset was taken from https://universe.roboflow.com/, and the burn images dataset was created. In the second stage, in order to determine the accuracy of the developed system and artificial intelligence model, the patients admitted to the hospital were identified with our own design Burn Wound Detection Android application. Results: In our study, YOLO V7 architecture was used for segmentation, classification, and object detection. There are 21018 data in this study, and 80% of them are used as training data, and 20% of them are used as test data. The YOLO V7 model achieved a success rate of 75.12% on the test data. The Burn Wound Detection Android mobile application that we developed in the study was used to accurately detect images of individuals. Conclusion: In this study, skin burn images were segmented, classified, object detected, and a mobile application was developed using artificial intelligence. First aid is crucial in burn cases, and it is an important development for public health that people living in the periphery can quickly determine the degree of burn through the mobile application and provide first aid according to the instructions of the mobile application. (c) 2024 Elsevier Ltd and ISBI. All rights reserved.