https://hdl.handle.net/20.500.12294/1383 Faculties Fri, 10 Apr 2026 12:48:31 GMT 2026-04-10T12:48:31Z https://hdl.handle.net/20.500.12294/4140 RB1 gene mutations and genetic spectrum in retinoblastoma cases Odemis, Demet Akdeniz; Kebudi, Rejin; Bayramova, Jamila; Erciyas, Seda Kilic; Turkcan, Gozde Kuru; Tuncer, Seref Bugra; Erdogan, Ozge Sukruoglu; Celik, Betul; Gultaslar, Busra Kurt; Bay, Sema Buyukkapu; Tuncer, Samuray; Yazici, Hulya The aim of the study was to investigate the frequency and types of mutations on the retinoblastoma gene (RB1 gene) in Turkish population. RB1 gene mutation analysis was performed in a total of 219 individuals (122 probands with retinoblastoma, 14 family members with retinoblastoma and 83 clinically healthy family members). All 27 exons and close intronic regions of the RB1 gene were sequenced for small deletions and insertions using both the Sanger sequencing or NGS methods, and the large deletions and duplications were investigated using the MLPA analysis and CNV algorithm. The bilateral/trilateral retinoblastoma rate was 66% in the study population. The general frequency of RB1 gene mutation in the germline of the patients with retinoblastoma was 41.9%. Approximately 51.5% of the patients were diagnosed earlier than 12 months old, and de novo mutation was found in 32.4% of the patients. Germline small genetic rearrangement mutations were detected in 78.9% of patients and LGRs were detected in 21.1% of patients. An association was detected between the eye color of the RB patients and RB1 mutations. 8 of the mutations detected in the RB1 gene were novel in the study. Mon, 01 Jan 2024 00:00:00 GMT https://hdl.handle.net/20.500.12294/4140 2024-01-01T00:00:00Z https://hdl.handle.net/20.500.12294/4139 Adsorption and desorption of hydroxychloroquine onto sulphur doped graphene powders as a potential drug for COVID-19 Acar, Tayfun; Arvas, Melih Besir; Arvas, Busra; Ucar, Burcu; Sahin, Yucel Hydroxychloroquine (HCQ) is a very substantial drug active substance that was approved for emergency use by the FDA during the peak of the COVID-19 pandemic due to its potent antiviral properties. In this study, adsorption and desorption of hydroxychloroquine on sulfur (S)-doped graphene powders were investigated. While the adsorption experiments were carried out in the environment of distilled water (pH 5.0-6.0), HEPES buffer (pH 7.6), and Tris.HCl buffer (pH 8.0) the desorption studies were performed in distilled water. The HCQ adsorbed S-doped graphene powders were characterized by UV-Vis, FT-IR, XRD, BET and TEM techniques. According to UV-Vis measurements, the adsorption efficiency in the HEPES buffer medium at pH 7.6 was the highest (68.72% for H3 (HCQ adsorption with SGr3 graphene in HEPES medium)). FT-IR and XRD analyses confirmed the presence of HCQ on the graphene powders' surface. While morphological changes on the surfaces of graphene powders were imaged by TEM, BET surface area changes proved the HCQ adsorption. The in vitro toxicity of the developed H3 was found to be lower than that of HCQ alone on the L929 cell line. These fundamental findings of the surface interaction between HCQ and graphene are precious for the design and optimization of a targeted drug based on this molecule and material. The adsorption/desorption features of HCQ onto graphene-based carrier systems which in particular doped with sulfur from functional metals have been investigated for the first time. Mon, 01 Jan 2024 00:00:00 GMT https://hdl.handle.net/20.500.12294/4139 2024-01-01T00:00:00Z https://hdl.handle.net/20.500.12294/4138 Development of sinter linings for high-speed trains Bebekoglu, Sunay; Topuz, Ahmet; Cakir, Esin; Adsoy, Abdulhamit; Yildiran, Turgay In this study, brake linings with Cu (copper)-based and Cu-10Sn (bronze)-based matrix structures have been developed and produced by the powder metallurgy method using sinter metal technology for use in high-speed trains. The developed linings were compared with commercial high-speed train linings. Firstly, the mixing process was carried out in a Turbulo 3V three-dimensional mixer for 4.5 h at 50 rpm. The pressing process was performed at room temperature, under the pressure of 350-450 MPa, and the sintering temperature for Cu-based linings was 1,000 °C, while for Cu-10Sn-based linings, it was 800 °C. After the pressing and sintering processes, lining sample density calculations were conducted, and hardness tests were carried out in the Rockwell L scale. Shear strength tests, friction coefficient, and wear tests were conducted according to SAE J 661 standards. It was observed that sinter metal brake linings with Cu and Cu-10Sn main matrix structures showed similar properties and met the technical requirements. It was determined that the developed production prescriptions are promising for industrial production and patent studies. © 2024 Walter de Gruyter GmbH, Berlin/Boston 2024. Mon, 01 Jan 2024 00:00:00 GMT https://hdl.handle.net/20.500.12294/4138 2024-01-01T00:00:00Z https://hdl.handle.net/20.500.12294/4136 Clarification of red grape juice by amine-functionalized magnesium silica aerogel Kara, Ilkay Turhan; Yucel, Sevil; Arici, Muhammet The clarification conditions and the selection of the clarification agent are pivotal in eliminating the haze components from red grape juice (RGJ) while minimizing the loss of functional color components. In this context, we synthesized a water glass-based APTES functionalized magnesium silica aerogel (MSA-NH 3 ) incorporating 61.44 molecules/nm 2 of amine groups, resulting in a positively charged zeta potential value of 33.9 mV (pH 3.4) for clarification of RGJ by targeting negatively charged polyphenols. The optimum clarification conditions using MSA-NH 3 were determined as 0.18 g MSA-NH 3 /L RGJ, 20 degrees C, and 60 min through the application of BoxBehnken design. Under these conditions, MSA-NH 3 exhibited excellent adsorption of haze components (3.61 NTU), outperforming the commercial bentonite-gelatine combination (BGC) (5.45 NTU). Furthermore, it exhibited greater efficacy in preserving anthocyanins while adsorbing browning components. MSA-NH 3 has a high potential to serve as a functional alternative clarification agent in the beverage industry due to its promising clarification performance. Mon, 01 Jan 2024 00:00:00 GMT https://hdl.handle.net/20.500.12294/4136 2024-01-01T00:00:00Z