İstanbul Sağlık ve Teknoloji Üniversitesi Kurumsal Akademik Arşivi
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Güncel Gönderiler
Poly(bromophenol blue)/ CoSn(OH)6 cubic particles modified pencil graphite electrode for electrochemical determination of diphenhydramine
(Nature Research, 2026) Karakaya, Serkan; Bakırdere, Sezgin; Şaylan, Meltem; Dilgin, Yusuf
In this study, a poly(bromophenol blue) (poly(BPB))-coated CoSn(OH)6 cubic particles -modified pencil graphite electrode (poly(BPB)@CoSn(OH)6/PGE) was developed, and its electrochemical activity towards diphenhydramine (DPHN) oxidation was systematically investigated. Cyclic voltammetric studies revealed that the oxidation of DPHN at the modified electrode is governed by a diffusioncontrolled process, indicating strong interaction between DPHN molecules and the poly(BPB) film. The incorporation of the CoSn(OH)6 cubic structure enhances electron transfer kinetics by increasing the density of electroactive sites and facilitating charge transport across the electrode interface. This cooperative interaction between the conductive polymer and metal hydroxide structure results in a significant amplification of the oxidation response. Under optimized conditions, the proposed electrode exhibited a linear response in the concentration range of 1.0–500.0 µM with a detection limit (LOD) of 0.30 µM. Although the analytical performance is comparable to previously reported systems, the present work provides deeper insight into the role of polymer–metal hydroxide interfaces in governing electrochemical sensing behavior. The sensor also demonstrated acceptable selectivity and applicability in pharmaceutical, biological, and environmental samples. These findings highlight the importance of interfacial design in improving electrochemical performance and offer a useful framework for developing advanced hybrid sensing platforms.
Production-phase carbon footprint of photopolymer resin workflows for direct-print orthodontic aligners: A screening carbon-footprint assessment
(MDPI Publishing, 2026) Özcan, Mustafa; Allaf, Ferdi
Direct-print aligners are widely presented as the environmentally preferable alternative to thermoforming, but which part of the process governs the carbon released during manufacture has not been established. Four commercial printer–resin workflows were modelled: Graphy Tera Harz resin on a Uniz NBEE (A) and an Asiga MAX 2 (B), the LuxCreo iLux Pro as a closed chain (C), and Graphy resin on a DentaFab Sega Pro (D). Energy, material and throughput data came from the manufacturers. Production-phase CO2e per aligner was propagated through 10,000 Monte Carlo draws, with the resin emission factor sampled across its full published range (3.0–6.5 kg CO2e/kg) and the thermoformed comparator represented as a distribution. Mean footprints were 0.043, 0.036, 0.089 and 0.020 kg CO2e per aligner (95% uncertainty intervals were 0.032–0.056, 0.026–0.047, 0.077–0.101 and 0.016–0.025), against a thermoformed median of 0.190. Direct printing was the lower of the two in every paired iteration. Resin dominated, contributing 41–79% of the total; solvent added a further 41% in the one workflow using it, while electricity of all kinds accounted for 19–36%. Thermoforming would match direct printing only at series lengths of 45 to 202 aligners, far above the 14–30 of clinical practice; under the most unfavourable resin factor the margin narrowed but did not close. Material efficiency, not energy sourcing, is where reductions are available.
Biocompatibility of five occlusal splint materials produced by four fabrication methods: An in vitro comparative study
(Springer Nature Link, 2026) Atay, Ayşe; Ayvalıoğlu Şamiloğlu, Demet Çağıl; Yıldırım, Zafer; Bozok, Vildan; Gökçen Rohlig, Bilge; Karabece, Ebru; Sevük, Çetin
Background To evaluate the cytotoxicity, cell death, interleukin-6 (IL-6) release, and surface roughness of five occlusal splint materials produced by four different fabrication methods on L929 mouse fibroblasts. Methods 240 disc-shaped specimens (15×2 mm) were fabricated from milled polymethyl methacrylate (PMMA), milled polyetheretherketone (PEEK), 3D-printed photopolymer resin, thermoformed polyethylene terephthalate glycol (PET-G), and auto-polymerizing PMMA. Extracts were prepared following ISO 10993-12 and collected on days 1, 3, and 7; at each time point the extracts of four specimens were pooled and applied to three replicate wells. Cell viability (XTT), total cell death (Annexin V-FITC/PI flow cytometry), IL-6 release (ELISA), and surface roughness (Ra, contact profilometer) were assessed. As the replicate wells were technical replicates of a single pooled extract, the biological data are reported descriptively; surface roughness was analyzed by one-way ANOVA with Tukey’s HSD test (p<0.05). Results On day 7, the auto-polymerizing PMMA group showed the lowest cell viability (68.44±3.48%) and was the only material to fall below the 70% threshold of ISO 10993-5. Cell viability remained above the 70% threshold in all other groups at all time points. Total cell death was low throughout (1.40–3.20%; untreated control 1.50%), with the highest day-7 values in the thermoformed PET-G (3.20±0.30%) and auto-polymerizing PMMA (3.07±0.86%) groups. IL-6 was below the limit of detection (18.75 pg/mL) in most conditions; only the autopolymerizing PMMA group on day 7 yielded quantifiable IL-6, in two of three wells (33.78 and 42.55 pg/mL). The milled-PEEK and thermoformed PET-G groups showed the lowest Ra values, whereas the milled-PMMA group showed the highest (p=0.005). Conclusions In this in vitro extract model, the auto-polymerizing PMMA group was the only material falling below the 70% viability limit of ISO 10993-5 and the only one with quantifiable IL-6 on day 7. All other groups remained above this threshold throughout, and total cell death remained low in all groups. The milled and printed materials evaluated in the present study may therefore represent biologically more favorable options than the auto-polymerizing PMMA group. These findings are descriptive, based on a single pooled extract per condition, and apply only to the specific products tested.
Utilization patterns and clinical outcomes following oocyte cryopreservation in Turkey: A multicenter cohort study within a nationally regulated setting
(Galenos Publishing House, 2026) Aydın, Gerçek; Tavuz, Aziz İhsan; Uzelli Şimşek, Hayal; Simavlı, Serap; Doğer, Emek
Purpose: To analyse the utilization patterns, patient characteristics, and reproductive outcomes of oocyte cryopreservation (OC) performed under the current fertility preservation (FP) framework in Turkey. Methods: This retrospective multicenter cohort study analyzed data from Ministry of Health-accredited FP programs across Turkey between 2005 and 2026. The study included women who underwent OC for approved medical indications, predominantly diminished ovarian reserve and FP before gonadotoxic treatment. Primary outcomes were oocyte utilization rates and reproductive outcomes among women who returned to use their cryopreserved oocytes. Secondary outcomes included socio-demographic profiling and cycle-level characteristics. Results: A total of 1,582 women were included. Mean age at cryopreservation was 33.5±7.2 years. Most women underwent OC for diminished ovarian reserve (92.3%), while 7.6% underwent FP before treatment for malignant disease. Most participants were university-educated (63.9%) and employed (65.7%), with obstetrics and gynecology specialists being the primary source of awareness (53.3%). Mean anti-Müllerian hormone was 0.6±0.6 ng/mL, and a mean of 3.6±3.0 mature oocytes were cryopreserved per cycle. During the observation period, only 39 women (2.4%) returned to utilize their cryopreserved oocytes. Among thaw cycles, the clinical pregnancy rate per transfer was 15.6%, and the implantation rate was 12.7%. Conclusion: In this large multicenter cohort, OC was predominantly performed in women with diminished ovarian reserve, resulting in relatively limited oocyte yield and low observed utilization during the available follow-up period. These findings provide real-world data on the characteristics, utilization patterns, and reproductive outcomes of FP programs in Turkey and may help inform future clinical practice and policy discussions.
Novel 1-benzyl-oxindole indole hybrids targeting PDGFR-β, SRC, and c-MET signaling and inducing caspase-3-dependent apoptosis in pancreatic cancer cells
(Elsevier, 2026) Cinek, Tuğçe; Yıldırım, Merve; Cihan-Üstündağ, Gökçe; Genç Akar, Öyküm; Sancar, Serap; Erol-Bozkurt, Ayşe; Özen-Eroğlu, Güneş; Küçüker, Begüm; Öztay, Füsun; Kuruca, Serap; Bolkent, Şehnaz; Karalı, Nilgün
As part of our ongoing efforts to develop N-benzylated oxindole derivatives as multi-target anticancer agents, novel N-benzyl oxindole indoles (4a–z) were designed, synthesized and structurally characterized. Their cytotoxic activities were evaluated against HCT-116, HT-29, A549, MIA PaCa-2, A498, CAKI-1, MDA-MB-231, and MCF-7 cancer cells, as well as Beas2b noncancerous cells. Most compounds exhibited significantly stronger cytotoxicity and selectivity than the reference drug sunitinib malate. Mechanistic studies were performed on compounds 4a, 4b, 4d, 4g, 4i, 4q, and 4y, which displayed submicromolar cytotoxic effects (IC50 = 0.27- 0.97 μM) and high selectivity indices (SI = 91.3->370.4). Among these, compounds 4a, 4b, and, 4i, which exhibited stronger cytotoxic effects than sunitinib malate, significantly induced apoptosis and markedly suppressed general tyrosine kinase (TK) activity. Compounds 4a (IC50 = 0.27 μM, SI = 167.8) and 4b (IC50 = 0.48 μM; SI = 91.2) markedly reduced PDGFR-β and SRC signaling, and inhibited ERK signaling more potently than sunitinib malate (IC50 = 4.03 μM, SI = 3.2) in MIA PaCa-2 cells. Notably, compound 4a also exhibited stronger reduction c-MET signaling than sunitinib malate, whereas compound 4b was less effective against this target. Overall, compound 4a displayed the most potent multi-target inhibitory profile and was identified as lead candidate. Molecular docking studies further supported its stable binding within the ATPbinding pockets of PDGFR-β, SRC, and c-MET kinases, consistent with its observed inhibitory activity. Further mechanistic studies demonstrated that compound 4a induces caspase-3-mediated apoptosis through a Bax/Bcl-2- independent pathway, accompanied by increased levels of cytochrome c and p53. Collectively, these findings identify compound 4a as a potent, selective, and multi-target lead candidate for further development against pancreatic cancer.
