Meslek Yüksekokulları

Anatomical and palynological studies on Turkish Primula taxa (Primulaceae) and their taxonomic and phylogenetic significance

Wed, 01 Jan 2025 00:00:00 GMT

Anatomical and palynological studies on Turkish Primula taxa (Primulaceae) and their taxonomic and phylogenetic significance Ulukuş, Deniz; Özkaymakoğlu, Esengül; Stubbs, Rebecca; Baykal, Hüseyin; Coşkunçelebi, Kamil; Tugay, Osman; Keller, Barbara; Conti, Elena; Celep, Ferhat Anatomical (scape, pedicel, leaf lamina, and leaf midrib) and pollen morphological features of 11 taxa belonging to the genus Primula subgen. Primula (P. vulgaris subsp. vulgaris, P. vulgaris subsp. rubra, and P. megaseifolia, P. meyeri, P. elatior subsp. pallasii, P. pseudoelatior, P. veris subsp. columnae, P. veris subsp. macrocalyx) and subgen. Aleurita (P. longipes, P. algida, and P. auriculata) were examined using light and scanning electron microscopy to shed light on the existing taxonomic and phylogenetic relationships. The anatomical and palynological features of the majority of the taxa studied were revealed for the first time in this study. In anatomical studies, the very large intercellular space under the epidermis, the number of sclerenchyma layers in the scape, and the midrib shape in the leaf lamina were found to be of taxonomic importance at the subgenus level. In palynological studies, pollen grain size, pollen surface ornamentation patterns, and pollen aperture types could be used as important characters to distinguish species, sections, and subgenera. Significant differences were found between subgenera and between the pollen grains of pin and thrum flowers of the same taxon. Mostly, the subgen. Aleurita taxa had significantly smaller pollen grains than the subgen. Primula taxa, and pollen grains from flowers with pin morphology were smaller than those from flowers with thrum morphology. Our studies showed that both anatomical and palynological features have not only taxonomic but also phylogenetic importance.

Investigation of structural, hardness, adhesion, and tribological properties of CrN and AlCrN coatings deposited on cylinder liner

Wed, 01 Jan 2025 00:00:00 GMT

Investigation of structural, hardness, adhesion, and tribological properties of CrN and AlCrN coatings deposited on cylinder liner Aktarer, Semih Mahmut; Sert, Yaşar; Küçükömeroğlu, Tevfik Friction between cylinder liners and piston rings is one of the major energy losses in engines. Minimizing this friction reduces fuel consumption, lowers emissions, and enhances performance. To address this, CrN and AlCrN coatings were applied to grey cast iron (GCI) cylinder liners using cathodic arc deposition method. Their tribological properties were evaluated under varying loads through reciprocating wear tests in dry and lubricated conditions. The structure of the coatings was characterized by electron microscopy (SEM-EDS) and X-ray diffraction (XRD), while the hardness and adhesion properties were characterized by nanoindentation and scratch testing. The CrN coating showed 21% lower hardness but 18% higher adhesion strength and superior crack resistance compared to AlCrN. In dry, low-load conditions, AlCrN's higher hardness resulted in 30% better wear resistance. However, under high-load conditions, the wear resistance of CrN coating is about 3 times higher than AlCrN coating due to its improved adhesion properties. CrN and AlCrN coatings reduced wear rates by approximately 70 and 24 times, respectively, compared to GCI. In lubricated conditions, CrN's wear rate was 5.3 times lower than GCI and 2.4 times lower than AlCrN. These findings show that AlCrN is ideal under low loads, while CrN is better for high-loads.

A case-control study on the role of carbonic anhydrase autoantibodies in the pathogenesis and diagnosis of fibromyalgia

Wed, 01 Jan 2025 00:00:00 GMT

A case-control study on the role of carbonic anhydrase autoantibodies in the pathogenesis and diagnosis of fibromyalgia Kılıç, Hülya; Hasanova, Narmin; Topaloğlu, Mehmet Serhat; Şahin, Elif; Sağlam, Neslihan; Alemdar, Nihal Türkmen; Menteşe, Ahmet To investigate the levels and diagnostic significance of carbonic anhydrase I (CAI) and II (CAII) autoantibodies and oxidative stress status in fibromyalgia syndrome (FMS) patients. A total of 59 FMS patients and 53 healthy controls were included. CAI and CAII autoantibody levels were measured using a manual ELISA protocol. Serum malondialdehyde (MDA), serum total oxidant status (TOS), serum total antioxidant status (TAS), and oxidative stress index (OSI) were also analyzed. The mean CAI and CAII autoantibody levels were significantly higher in the FMS group compared to the control group (p < 0.000 and p < 0.003, respectively). FMS patients had significantly higher MDA, TOS and OSI levels(p < 0.000 for all comparisons), and lower TAS levels compared to controls but no significant differences (p > 0,705). Elevated CAI and CAII autoantibodies and altered oxidative stress markers in FMS patients suggest autoimmune processes and oxidative stress involvement in the pathogenesis of FMS, providing new insights into potential diagnostic and therapeutic approaches.

Selection, heterologous production, and functional characterization of a thermostable xylanase from anoxybacillus for dough and bread quality enhancement

Wed, 01 Jan 2025 00:00:00 GMT

Selection, heterologous production, and functional characterization of a thermostable xylanase from anoxybacillus for dough and bread quality enhancement Karaoğlu, Hakan; Ramadan, Khaled M.A.; Al Hashedi, Sallah A.; AlShoaibi, Adil; Iqbal, Zafar; Aydın, Rukiye; Secgin, Busra Abanoz; Seçgin, Zafer; Bendary, Eslam S.A.; Mahmoud, Mohamed A.A.; Emanet, Züleyha Akpınar; Efe, Derya Thermostable xylanases contribute to enhancing dough properties and bread quality in industrial baking. This study aimed to identify a high-yield thermophilic xylanase producer, optimize its heterologous expression, and evaluate its functional role in baking applications. Screening of 19 Anoxybacillus species identified A. bogrovensis as the highest xylanase producer. The xyn gene was cloned and expressed in Escherichia coli BL21, and the recombinant enzyme (iAboXYN) was purified using heat treatment, ion-exchange, and hydrophobic interaction chromatography. Biochemical characterization confirmed high thermal and pH stability, with over 50 % activity retained up to 80 °C and moderate stability observed at 90 °C, along with broad pH adaptability (5.0-8.5) and metal ion resistance. The enzyme's functional role in dough processing was assessed using a direct dose-response analysis, demonstrating improvements in dough stability, elasticity, and hydration efficiency while reducing mixing time and water absorption. Application in bread formulations led to enhanced loaf volume, improved crumb structure, and better texture, with sensory evaluation confirming superior quality. Preference ranking tests further validated the improved consumer perception of iAboXYN-treated bread. These findings establish iAboXYN as a functional biocatalyst for enzyme-assisted baking, offering a scalable approach to optimizing dough properties and improving bread quality.