Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395

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  • Article
    Citation - WoS: 1
    Citation - Scopus: 2
    Green Synthesis and Characterization of Zinc Oxide Nanoparticles via Thyme for Biomedical Applications: Effect of Plant Extract Concentration and Drying Method
    (Springer, 2025-10-15) Karakaya, Humeyra; Kizilates, Burcu; Erdem, Ilker
    Green synthesis of nano particles using plant extracts is sustainable, cost-effective, and eco-friendly. However, the synthesis parameters are still being investigated. In this study, zinc oxide nanoparticles (ZnO NPs) were prepared via thyme extract (green synthesis) and the effect of synthesis parameters were investigated. Samples with different concentrations of thyme plant extract (PE) (10, 16 & 24% (v/v) PE / Zn salt solution) were prepared and two different drying methods (freeze-drying (FD) and oven-drying (OD)) were performed. XRD results showed the hexagonal crystalline ZnO were formed with considerable crystallinity (70.8-75.1%) without further heat treatment (calcination). The crystallite sizes of ZnO NPs were determined to be in the range of 11.9-14.8 nm. The ZnO NPs prepared via PE concentration of 16% (v/v) and freeze-drying was with the finest crystallite size (11.9 nm) and considerable crystallinity (72.9%). ZnO NPs prepared via FD method were found to have smaller particle sizes, thus providing a higher surface-to-volume ratio. DLS (dynamic light scattering) analysis was used for determining the particle size distribution (PSD) and surface charge of ZnO NPs at acidic, neutral and basic pH values. The antibacterial characteristics of ZnO NPs were determined against Gram (+) and (-) bacteria. The ZnO NPs with the finest microstructure (16% PE (v/v), FD) had the highest antibacterial activity. The green synthesized ZnO NPs prepared in this study may be promising candidates for various applications including biomaterials and biomedical applications with their fine microstructure and considerable antibacterial activity.
  • Article
    Enhanced Photoluminescence via Plasmonic Gold Nanoparticles and Improved Stability of Perovskite Nanocrystals in Macroporous (Polydimethylsiloxane) PDMS Matrices
    (Springer, 2025-10-09) Ocal, Sema Karabel; Tiras, Kevser Sahin; Onses, M. Serdar; Mutlugun, Evren
    In this work, we report a simple and cost-effective method for improving both the environmental stability and photoluminescence quantum efficiency (PLQY) of perovskite nanocrystals (PNCs). Through their embedding in a specially designed macroporous polydimethylsiloxane (MPDMS) matrix and incorporation of plasmonic gold nanoparticles (Au NPs), remarkable improvements are achieved. The resulting MPDMS@PNC composites are seen to retain near-unity quantum efficiency even after 24-h immersion in water and are observed to retain over 85% of the original efficiency even at 75 degrees C, displaying excellent thermal stability. More interestingly, by incorporating Au NPs and subjecting the material to mechanical pressure, the lifetime of the PNCs gets further increased. This is due to the more intimate spatial arrangement of Au NPs in the porous matrix, enhancing localized surface plasmon resonance (LSPR) coupling and thereby enhancing the photoluminescence (PL) of the PNCs. In general, this approach offers a scalable and robust route to designing stable, high-performance perovskite-based materials for next-generation optoelectronic applications.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Pangenome Analysis and Genome-Guided Probiotic Evaluation of Cyclic Dipeptides Producing Levilactobacillus Brevis DY55bre Strain From a Lactic Acid Fermented Shalgam to Assess Its Metabolic, Probiotic Potentials, and Cytotoxic Effects on Colorectal Cancer Cells
    (Springer, 2025-10-01) Yetiman, Ahmet E.; Horzum, Mehmet; Kanbur, Ertan; Cadir, Mehmet; Bahar, Dilek; Gurbuz, Serife; Akbulut, Mikail
    This study investigates the genetic, metabolic, and probiotic characteristics of Levilactobacillus brevis DY55bre, a strain isolated from the traditional Turkish fermented beverage, shalgam. Whole-genome sequencing revealed a circular genome of 2.485 Mb with a GC content of 45.72%, predicted 2791 genes, and multiple CRISPR-Cas systems. Pangenome analysis demonstrated an open structure, with 18.9% core genes and 103 strain-specific genes, highlighting its genetic diversity. The DY55bre exhibits heterofermentative carbohydrate metabolism due to the presence of the araBAD operon and the lack of 1-phosphofructokinase (pfK) and fructose-1,6-bisphosphate aldolase enzymes. Probiotic evaluation revealed firm survival under simulated gastrointestinal conditions, including resistance to acidic pH (as low as 3.0) and bile salts (up to 1%), along with significant adhesion to intestinal epithelial cell lines (HT29;59.3%, Caco-2;87%, and DLD-1;60.8%). The strain exhibited high auto-aggregation (84.55%) and cell surface hydrophobicity (56.69%), essential for gut colonization. Safety assessments confirmed its non-hemolytic nature and absence of horizontally acquired antibiotic resistance genes. Notably, GC-MS analysis identified bioactive cyclic dipeptides, Cyclo(D-Phe-L-Pro) and Cyclo(L-Leu-L-Pro), which demonstrated cytotoxic effects against colorectal cancer cell lines, with IC50 values of 7.71 mg/mL for HT29 and 3.19 mg/mL for DLD-1. The cell-free supernatant exhibited antimicrobial activity against pathogens, likely due to the synergistic effects of cyclic dipeptides, organic acids, and other metabolites. Antioxidant assays revealed significant ABTS+ (76.63%) and DPPH (34.25%) radical scavenging activities, while cholesterol assimilation tests showed a 27.29% reduction. These findings position the DY55bre as a promising candidate for functional foods, nutraceuticals, and therapeutic applications, warranting further in vivo validation.