Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 2Citation - Scopus: 2Subwavelength Thickness Characterization of Curved Dielectric Films Exploiting Spatially Structured Entangled Photons(Optica Publishing Group, 2023) Ataç, Enes; Dinleyici, Mehmet SalihPrecise determination of thin dielectric film optical properties is a critical issue for fiber optic sensor technologies. However, conventional methods for the optical characterization of these films not only are generally complex and tedious processes on curved surfaces but also require well-calibrated and overly sophisticated devices. We, on the other hand, propose a novel and practical quantum-based phase diffraction scheme to characterize the thickness of ultra-thin transparent dielectric films coated on an optical fiber beyond the classical diffraction limits in this paper. The approach is implemented by evaluating the effect of thickness variations on the highly visible two-photon diffraction pattern's zero crossings and amplitudes. The mathematical model and numerical simulations con-tribute to a better understanding of how the spatially structured entangled photons improve thickness precision with the help of intensity correlations and a confocal aperture. To prove the impact of the proposed system, it is compared with the classical phase diffraction method in the literature via simulations. According to the results, the thickness of the transparent dielectric films can be accurately estimated below one-twentieth of the wavelength of interest. & COPY; 2023 Optica Publishing GroupArticle Citation - WoS: 17Citation - Scopus: 19Bacterial Surface, Biofilm and Virulence Properties of Listeriamonocytogenes Strains Isolated From Smoked Salmon and Fish Food Contact Surfaces(Elsevier, 2021) Sudağıdan, Mert; Özalp, Veli Cengiz; Öztürk, Orhan; Yurt, Mediha Nur Zafer; Yavuz, Orhan; Taşbaşı, Behiye Busra; Uçak, Samet; Mavili, Zehra Seda; Çoban, AyşenBiofilm formation is one of the defense mechanisms of bacteria against disinfectants and antimicrobials. The aim of this study was to determine biofilm-forming L.monocytogenes from fish processing and salmon surfaces. Biofilm formation at 15, 25, 37, and 40 degrees C from 1 to 6-days period, adhesion to glass, polypropylene and stainless-steel surfaces, bacterial surface charge and hydrophobicity was determined. Adhesion behavior of the strains was evaluated using Surface Plasmon Resonance (SPR) technique. Totally 32 L.monocytogenes strains belonging to serogroups IIa (n:17), IIc(n:14) and IVb(n:1) were detected from 1320 swabs and 16 smoked salmons. Biofilm formation tests revealed that 21 strains form biofilm on microplate by increasing time and temperature. Although all strains strongly formed biofilm on glass surfaces, two strains slightly adhered polypropylene surfaces. High surface roughness of stainless-steel FeCrNi alloy (Ra = 4.15 nm) and CoCrMo alloy (Ra = 10.75 nm) increased biofilm formation of L.monocytogenes on stainless-steel surfaces. Zeta potential results showed that non-biofilm formers were more negatively charged after 6-days and hydrophobicity couldn't give a distinct distribution among biofilm formers and non-formers. SPR analysis method was evaluated to distinguish biofilm formers to adhere SPR gold chip surfaces. PCR results revealed that all strains were positive for hylA, iap, actA, plcA, plcB, fri, flaA, inlA, inlB, inlC, inlJ, and lmo1386 genes. Additionally, all strains were susceptible to penicillin, ampicillin, meropenem, erythromycin and trimethoprim-sulfamethoxazole. Biofilm-forming, virulence properties of L. monocytogenes strains isolated from fish processing surfaces and smoked salmons were evaluated and SPR was used to differentiate biofilm formers as a sensitive technique for biofilm studies.Article Citation - WoS: 40Citation - Scopus: 44Plasmon-Enhanced Photocatalytic and Antibacterial Activity of Gold Nanoparticles-Decorated Hematite Nanostructures(Elsevier Ltd., 2021) Emre, Alp; İmamoğlu, Rizvan; Savacı, Umut; Turan, Servet; Kazmalı, M. Kürşat; Genç, AzizHematite (alpha-Fe2O3) nanoparticles have received significant attention from the researchers due to their favorable and desirable properties in diverse applications. In the present study, single-crystalline hematite pseudo-nanocubes and porous nanorods were synthesized by the hydrothermal route without the usage of any surfactant agents, which were then decorated with gold nanoparticles hidrothermally in an aqueous solution in order to increase the solar energy conversion efficiency. The photocatalytic activities of synthesized nanoparticles were studied against Rhodamine B (RhB) under the illumination of AM 1.5 solar simulator. The excellent photocatalytic efficiency was obtained by changing morphological features of hematite nanostructures, along with the photocatalytic performance enhancement up to 25% thanks to the surface plasmon resonances for the gold nanoparticles-decorated hematite nanostructures. For instance, gold-nanoparticles decorated hematite pseudo-nanocubes almost completely degraded all the RhB after 30 min of illumination. It was also observed that all hematite products, with and without gold decoration, exhibited an impressive antibacterial effect and showed the lethal effect in E.coli. The same nanoparticles being photocatalytically active for organic pollutant degradation and having antibacterial effect may have a good potential for waste water remediation applications. (C) 2020 Elsevier B.V. All rights reserved.Conference Object Kanser Öntanısı için Hücredışı Veziküller Kullanılarak Plazmonik Temelli Metodoloji Geliştirme(Institute of Electrical and Electronics Engineers Inc., 2017) Erdoğan, Duygu; Alduran, Yeşim; Yıldız, Ümit Hakan; Arslan Yıldız, AhuSon yıllarda, vücut sıvılarında bulunan hücredışı veziküller kanserde tanı biyobelirteci olarak kullanılmaktadır. Veziküllerin içeriği kanserin türünü ve seviyesini belirlemede rol oynayabilmektedir. Bu vezikülleri yakalama işleminde, genel olarak, Akış Sitometrisi (Flow cytometry), Western Blot, Enzime-bağlı İmmunosorbent Deneyi (ELISA) ve Yüzey Plazmon Rezonansı (SPR) metodolojileri kullanılmaktadır. Bu çalışmada vezikülleri yakalamaya yönelik plazmon temelli bir deney platformu üretilmesi önerilmiştir. Bu plazmonik platform, yüzeyde yapılacak modifikasyonlarla, yüksek hassasiyet oluşturabileceğimiz Lokalize Yüzey Plazmon Resonansı temellidir.