Person: ÜNAL YILDIRIM, SEMRA
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ÜNAL YILDIRIM
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SEMRA
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Publication Metadata only Combination of proteasome inhibitors with temozolomide to increase the anti-tumor effect in 3D culture model of glioblastoma(ELSEVIER SCIENCE INC, 2018) YILMAZ GÖLER, AYŞE MİNE; Unal, Semra; Gokce, Tilbe; Arslan, Sema; Yilmaz, Ayse Mine; Gunduz, Oguzhan; Karademir, BetulPublication Metadata only Metabolic Biomarkers and Neurodegeneration: A Pathway Enrichment Analysis of Alzheimer's Disease, Parkinson's Disease, and Amyotrophic Lateral Sclerosis(MARY ANN LIEBERT, INC, 2016) KAZAN, DİLEK; Kori, Medi; Aydin, Busra; Unal, Semra; Arga, Kazim Yalcin; Kazan, DilekNeurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS) lack robust diagnostics and prognostic biomarkers. Metabolomics is a postgenomics field that offers fresh insights for biomarkers of common complex as well as rare diseases. Using data on metabolite-disease associations published in the previous decade (2006-2016) in PubMed, ScienceDirect, Scopus, and Web of Science, we identified 101 metabolites as putative biomarkers for these three neurodegenerative diseases. Notably, uric acid, choline, creatine, L-glutamine, alanine, creatinine, and N-acetyl-L-aspartate were the shared metabolite signatures among the three diseases. The disease-metabolite-pathway associations pointed out the importance of membrane transport (through ATP binding cassette transporters), particularly of arginine and proline amino acids in all three neurodegenerative diseases. When disease-specific and common metabolic pathways were queried by using the pathway enrichment analyses, we found that alanine, aspartate, glutamate, and purine metabolism might act as alternative pathways to overcome inadequate glucose supply and energy crisis in neurodegeneration. These observations underscore the importance of metabolite-based biomarker research in deciphering the elusive pathophysiology of neurodegenerative diseases. Future research investments in metabolomics of complex diseases might provide new insights on AD, PD, and ALS that continue to place a significant burden on global health.Publication Metadata only Tissue engineering applications of bacterial cellulose based nanofibers(Springer, 2020-01-01) ÜNAL YILDIRIM, SEMRA; GÜNDÜZ, OĞUZHAN; UZUN, MUHAMMET; ÜNAL S., GÜNDÜZ O., UZUN M.Publication Metadata only Design and characterization of polycaprolactone-gelatin-graphene oxide scaffolds for drug influence on glioblastoma cells(PERGAMON-ELSEVIER SCIENCE LTD, 2019) ATASOY, BESTE MELEK; Unal, Semra; Arslan, Sema; Gokce, Tilbe; Atasoy, Beste Melek; Karademir, Betul; Oktar, Faik Nuzhet; Gunduz, OguzhanThree-dimensional (3D) scaffolds that mimic in vivo tumor microenvironments can be used to study tumor response to anticancer treatments, since most preclinical combination treatment strategy for anti-glioma were evaluated with traditional 2D cell culture. In this research, the nanofiber scaffolds of polycaprolactone (PCL) containing gelatin (Gel) nano/microparticles coated with different concentrations of graphene oxide (GO) and were successfully produced by combining electrospinning and electrospraying techniques. Scanning electron microscope (SEM), Fourier-transform infrared (FT-IR) spectroscopy and mechanical testing were used to characterize the structure and properties of the composites. The results show that gelatin and graphene particles can be well dispersed in the polycaprolactone nanofiber matrix by using the combination technique of electrospinning and electrospraying. The presence of 1 wt% graphene oxide increased mechanical strength of PCL/Gel scaffold and was found to be well consistent with the drug treatments (temozolomide and bortezomib) and radiotherapy by not showing additional toxicity.Publication Metadata only Effects of Polymethylsilsesquioxane concentration on morphology shape of electrosprayed particles(ELSEVIER SCIENCE BV, 2018) OKTAR, FAİK NÜZHET; Unal, Semra; Oktar, Faik Nuzhet; Gunduz, OguzhanThe investigation of unique sizes and shapes as they relate to various properties has become a great study for large field applications. Polymethylsilsesquioxane (PMSQ) particles are produced by electrospraying. Morphology of the electrosprayed particles develops from the needle-like to star-like particles by controlling the concentration of the polymer solution. Therefore, electrospraying process instead of conventional methods has opened up an alternative for the fabrication of particles by controlling with three main parameters (applied voltage, flow rate and concentration of the polymer) that are used to manipulate their morphologies during preparation. (C) 2018 Elsevier B.V. All rights reserved.Publication Metadata only Glioblastoma cell adhesion properties through bacterial cellulose nanocrystals in polycaprolactone/gelatin electrospun nanofibers(ELSEVIER SCI LTD, 2020) YILMAZ, BETÜL; Unal, Semra; Arslan, Sema; Yilmaz, Betul Karademir; Kazan, Dilek; Oktar, Faik Nuzhet; Gunduz, OguzhanGlioblastoma (GBM), the most common and extremely lethal type of brain tumor, is resistant to treatment and shows high recurrence rates. In the last decades, it is indicated that standard two-dimensional (2D) cell culture is inadequate to improve new therapeutic strategies and drug development. Hence, well-mimicked three-dimensional (3D) tumor platforms are needed to bridge the gap between in vitro and in vivo cancer models. In this study, bacterial cellulose nano-crystal (BCNC) containing polycaprolactone (PCL) /gelatin (Gel) nanofibrous composite scaffolds were successfully fabricated by electrospinning for mimicking the extracellular matrix of GBM tumor. The fiber diameters in the nanofibrous matrix were increased with an increased concentration of BCNC. Moreover, fiber morphology changed from the smooth formation to the beaded formation by increasing the concentration of the BCNC suspension. In-vitro biocompatibilities of nanofibrous scaffolds were tested with U251 MG glioblastoma cells and improved cell adhesion and proliferation was compared with PCL/Gel. PCL/Gel/BCNC were found suitable for enhancing axon growth and elongation supporting communication between tumor cells and the microenvironment, triggering the process of tumor recurrence. Based on these results, PCL/Gel/BCNC composite scaffolds are a good candidate for biomimetic GBM tumor platform.Publication Metadata only Production and characterization of calcium phosphates from marine structures: The fundamentals basics(Springer, 2019-01-01) ÜNAL YILDIRIM, SEMRA; GÜNDÜZ, OĞUZHAN; OKTAR, FAİK NÜZHET; ÜNAL S., GÜNDÜZ O., AKYOL S., Ben Nissan B., OKTAR F. N.Publication Metadata only Development of a nonwetting coating for packaging substrate surfaces using a novel and easy to implement method(WALTER DE GRUYTER GMBH, 2021) UZUN, MUHAMMET; Soez, Cagla Kosak; Ozomay, Zafer; Unal, Semra; Uzun, Muhammet; Sonmez, SinanThis study is about preparing different paper substrates with chemically stable hydrophobic and superhydrophobic surface coatings through spraying a mixture of poly(dimethylsiloxane) (PDMS) and inorganic particles. The method is easy to implement, reproducible and requires inexpensive starting materials. Non-colored and colored types of (i) raw paper (UC), (ii) glossy coated paper (GC) and (iii) matte coated paper (MC) surfaces were selected for surface modification through the coating application. Both water-based ink (WB) and solvent-based ink (SB) formulations were used to dye substrate surfaces. Investigations including surface wetting, optical and physical properties of the coated paper substrates revealed that the coating application method proposed is a promising lacquer alternative for packaging purposes.Publication Metadata only Synthesis, characterization, and biological properties of composites of hydroxyapatite and hexagonal boron nitride(WILEY, 2018) OKTAR, FAİK NÜZHET; Unal, Semra; Ekren, Nazmi; Sengil, Ahmet Z.; Oktar, Faik N.; Irmak, Ster; Oral, Ozlem; Sahin, Yesim M.; Kilic, Osman; Agathopoulos, Simeon; Gunduz, OguzhanHydroxyapatite (HA), obtained from bovine bones, was successfully reinforced with hexagonal boron nitrite (h-BN). h-BN/HA composites, with BN content up to 1.5 wt %, were sintered at various temperatures between 1000 and 1300 degrees C, in air. Well-sintered samples were obtained after sintering at 1200 and 1300 degrees C. The presence of h-BN contributed to dense, fine, and well-crystallized microstructure. The results of X-ray diffraction analysis and FT-IR spectroscopy showed that the produced composites comprised biphasic beta-TCP/HCA (HCA: carbonate partially substituted HA). High values of mechanical properties were achieved, namely compression strength 155 MPa for the sample 0.5% h-BN/HA and Vickers microhardness of 716 HV for the samples 1.5% h-BN/HA, both sintered at 1300 degrees C. U2OS human bone osteosarcoma proliferation and cell viability showed no adverse effect in the presence of h-BN/HA, suggesting the potential use of the produced materials as safe biomaterials in bone tissue engineering. (C) 2017 Wiley Periodicals, Inc.Publication Metadata only Effects of Ozone on Injury after Gamma Knife Radiosurgery(ELSEVIER SCIENCE INC, 2021) ÜNAL YILDIRIM, SEMRA; Emon, Selin Tural; Unal, Semra; Arslanhan, Ayca; Bozkurt, Suheyla Uyar; Meric, Zeynep Cingu; Ziyal, IbrahimBACKGROUND: At present, gamma knife radiosurgery plays an important role in neurosurgical procedures. Gamma knife radiosurgery has been used to treat many types of brain tumors and as a functional intervention. However, gamma knife treatment has a devastating effect on the normal brain parenchyma surrounding the target point. It causes increased vascular permeability, vasodilation, and swelling in endothelial cells. Ozone has antioxidant, antiapoptotic, and anti-inflammatory effects in the body. Thus, we evaluated the radioprotective effects of ozone in rats undergoing gamma knife radiation. METHODS: In the present study, 24 Sprague-Dawley male rats weighing 250-300 g in 3 groups of 8 rats each were used. The rats were selected randomly. The control group did not receive any gamma knife radiation. The other 2 groups received 50 Gy of radiation, with 1 group given ozone treatment and the other group not given ozone treatment after gamma knife radiosurgery. At 12 weeks after gamma knife radiation, the rats were sacrificed with high-dose anesthetic agents and the tissues prepared for evaluation. The slides were evaluated for necrosis, vacuolization, glial proliferation, and vascular proliferation using hematoxylin-eosin staining. Vascular endothelial growth factor (VEGF) and extracellular matrix metalloproteinase inducer (also known as CD147) were evaluated using immunohistochemical staining. RESULTS: VEGF expression in glial tissue was significantly less in the group receiving ozone (chi(2) = 15.00; df = 4; P = 0.005) compared with the group that had not received ozone and was similar to the expression in the control group. CONCLUSIONS: The lower expression of VEGF in the group receiving ozone might cause less edema in the surrounding tissue owing to less degradation of vascular permeability in the rat brain tissue.