https://hdl.handle.net/20.500.12809/8923 Sat, 04 Apr 2026 13:31:56 GMT 2026-04-04T13:31:56Z https://hdl.handle.net/20.500.12809/10899 Investigation of Structural, Morphological and Photoluminescence Properties of Electrospun Cu@PMMA Nanofibers Acar, Yasemin; Güngör, Elif; Çoban, Mustafa Burak; Kuru, Fatma; Kara Subaşat, Hülya In this work, a tetrameric Cu(II) Schiff base complex [Tetrakis((µ3-N-(3,5-dichlorosalicyclideneamino)ethanolato)-Cu(II))], (1), has been synthesized and structurally characterized by single crystal X-ray diffraction technique. In different concentrations (5–20 wt%), complex (1) has been doped into poly(methylmethacrylate) (PMMA) as the polymer matrix using by electrospinning technique to form Cu@PMMA nanofibers. Both complex (1) and electrospun Cu@PMMA nanofibers were characterized using various techniques including field emission scanning electron microscopy (FESEM), photoluminescence (PL) and Fourier transform infrared (FT-IR) spectroscopy. The photoluminescence (PL) characteristics of Cu@PMMA composite fibers in the solid-state were studied at room temperature. Furthermore, the temperature-dependent PL properties of Cu@PMMA nanofibers, with a weight% of 15%, were investigated within a temperature range of 10–300 K. Cu@PMMA nanofibers exhibited blue emission with excitation wavelength of 349 nm. Brilliant values of the chromaticity coordinates of the prepared photoluminescent nanofibers predict their possible use in blue solid-state lighting applications. Sun, 01 Jan 2023 00:00:00 GMT https://hdl.handle.net/20.500.12809/10899 2023-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/10789 Structural, Thermal, Optical and Antibacterial Properties of Co-doped (Dy3+/Eu3+): PEG + PVA Novel Transparent Hybrid Films Çoban, Mustafa Burak; Diken, Mehmet Emin; Doğan, Serap; Kara Subaşat, Hülya In this report, PEG + PVA + Dy3+:Eu3+ films with Eu3+ concentrations of 1–7wt% were prepared by solution casting method and characterized. The composites were characterized by PXRD, FTIR, UV–Vis, DMA, SEM, TGA and photoluminescence measurements, and also their antibacterial activities were tested by the diffusion method. Thermogravimetric analyzes show that increasing Eu3+ content outstandingly increases thermal stability. Moreover, the antibacterial properties of composites showed strong activities against E. coli and S. aureus with the addition of Dy3+ and Eu3+ ions to polymer blends. Optical measurement records presented that the optical band gap Eg progressively decreased from 4.66 eV for the undoped PEG + PVA blend film to 3.18 eV by increasing Eu3+ ions concentration. Charmingly, the room temperature PL results reveal that the enhancement of the emission of Eu3+ ions in the PEG + PVA polymer matrix after co-doping with Eu3+ ions, whereas the reduction of Dy3+ emission intensity, owing to energy migration from Dy3+ to Eu3+. Besides, according with low-temperature PL measurements indicate that the PL density gradually decreases due to thermal quenching as the temperature increases. With the temperature increased, the color coordinates gradually changed from orange to reddish-orange. These results show that Dy3+/Eu3+ doped polymer blends can likely of a promising candidate in varieties of applications including OLEDs, biosensors, polymer solar cells and optoelectronics devices. Sun, 01 Jan 2023 00:00:00 GMT https://hdl.handle.net/20.500.12809/10789 2023-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/10314 Multifunctional Dy@PVP and Ho@PVP one-dimensional nanofibers: Electrospinning synthesis, luminescent and magnetic properties Çoban, Mustafa Burak; Güngör, Elif; Acar, Yasemin; Alpaslan, Fatma Kuru; Kara Subaşat, Hülya In this paper, different concentrations of DyIII complex of {[Dy(2-stp)2(H2O)6].2(4,4′-bipy).5(H2O)}, and HoIII complex of {[Ho(2-stp)2(H2O)6].2(4,4′-bipy).5(H2O)} (2-stp= 2-sulfoterephthalate and 4,4′-bipy=4,4′-bipyridine), were doped into the polymer matrix of Poly(vinylpyrrolidinone) (PVP) using the electrospinning technique, forming a series of orangish-yellow and purish-yellow luminescent nanofibers of Dy@PVP and Ho@PVP. It was observed that DyIII/HoIII ions showed strong characteristic emission in the luminescent spectra of the composite nanofibers. Simultaneously, in comparison with the precursor DyIII/HoIII complex, the Dy@PVP or Ho@PVP nanofibers has a great improvement in the photo and thermal stability Sat, 01 Jan 2022 00:00:00 GMT https://hdl.handle.net/20.500.12809/10314 2022-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/9837 3-Pyridinylboronic Acid Ameliorates Rotenone-Induced Oxidative Stress Through Nrf2 Target Genes in Zebrafish Embryos Üstündağ, Fümet Duygu; Ünal, İsmail; Üstündağ, Ünsal Veli; Cansız, Derya; Beler, Merih; Karagöz, Atakan; Kara, Hülya Parkinson's disease (PD) is one of the most common forms of neurodegenerative diseases and research on potential therapeutic agents for PD continues. Rotenone is a neurotoxin that can pass the blood-brain barrier and is used to generate PD models in experimental animals. Boron is a microelement necessary for neural activity in the brain. Antioxidant, non-cytotoxic, antigenotoxic, anti-carcinogenic effects of boric acid, the salt compound of boron has been reported before. Boronic acids have been approved for treatment by FDA and are included in drug discovery studies and pyridine boronic acids are a subclass of heterocyclic boronic acids used in drug design and discovery as substituted pyridines based on crystal engineering principles. The aim of our study was to determine the effect of 3-pyridinylboronic acid in rotenone-exposed zebrafish embryos, focusing on oxidant-antioxidant parameters and gene expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) target genes gclm, gclc, hmox1a, nqo1, and PD related genes, brain-derived neurotrophic factor, dj1, and tnfa alpha. Zebrafish embryos were exposed to Rotenone (10 mu g/l); Low Dose 3-Pyridinylboronic acid (100 mu M); High Dose 3-Pyridinylboronic acid (200 mu M); Rotenone + Low Dose-3-Pyridinylboronic acid (10 mu g/l + 100 mu M); Rotenone + High Dose-3-Pyridinylboronic acid (10 mu g/l + 200 mu M) in well plates for 96 h post-fertilization (hpf). Our study showed for the first time that 3-pyridinylboronic acid, as a novel sub-class of the heterocyclic boronic acid compound, improved locomotor activities, ameliorated oxidant-antioxidant status by decreasing LPO and NO levels, and normalized the expressions of bdnf, dj1, tnf alpha and Nrf2 target genes hmox1a and nqo1 in rotenone exposed zebrafish embryos. On the other hand, it caused the deterioration of the oxidant-antioxidant balance in the control group through increased lipid peroxidation, nitric oxide levels, and decreased antioxidant enzymes. We believe that these results should be interpreted in the context of the dose-toxicity and benefit-harm relationship of the effects of 3-pyridinylboronic. Sat, 01 Jan 2022 00:00:00 GMT https://hdl.handle.net/20.500.12809/9837 2022-01-01T00:00:00Z