WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
Browse
Search Results
Article Synthetic Memory: A Key Link Between Biocatalytically Synthesized Polyesters and Melt Electrowriting Performance(Taylor & Francis inc, 2025) Yıldız, Ümit Hakan; Yildiz, Umit Hakan; 01. Izmir Institute of Technology; 04. Faculty of Science; 04.01. Department of ChemistryThe biocatalytic synthesis of polycaprolactone (PCL) and its copolymers has garnered significant attention due to their reduced toxicity and enhanced 3D processability compared to metal-catalyzed alternatives. The objective of this study is to employ biocatalysts-citric acid (CA), glycolic acid (GA) and salicylic acid (SAA)-and explore their catalytic effects on the synthesis of poly(epsilon-caprolactone) (PCL) and poly(epsilon-caprolactone)-b-poly(delta-valerolactone) (PCL-b-PVL) block copolymers. Additionally, we aimed to examine the link between synthetic memory of resultant PCL and PCL-b-PVL polymers and their melt electrowriting performance. Nuclear magnetic resonance analysis confirms successful synthesis of copolymers by monitoring signals of hydrogens at 2.30 ppm. Differential scanning calorimetry results reveal shifts in thermal properties of copolymers upon varying biocatalysts CA-, SAA- and GA-catalyzed copolymers exhibit Tm values between similar to 52 and 54 degrees C. Melt electrowriting (MEW) results demonstrate that catalyst selection plays significant role in fiber morphology and scaffold architecture, with GA- and CA-catalyzed copolymers exhibiting finer fibers (5-8 mu m), while SAA led to thicker fibers (similar to 12 mu m) and reduced spacing. Moreover, precipitation solvents MeOH and acetonitrile (ACN) affect fidelity, with ACN-prepared scaffolds exhibiting more uniform fiber diameters. Atomic force microscopy imaging of electrowritten scaffolds made of ACN- and MeOH-precipitated PCL-b-PVL both exhibit large (>15 mu m) and smaller (<10 mu m) spherulitic structure as major topological features. These findings confirm that the synthetic memory of polyesters-governed by catalyst choice and processing conditions-directly influences their printability, making them promising candidates for MEW-based biomedical scaffolds in tissue engineering, where fine fiber morphology and architectural fidelity are essential for cell attachment and tissue regeneration.Article The Infinitude of the Primes and Some Coloring Theorems(Taylor & Francis inc, 2025) Göral, Haydar; Goral, Haydar; 04.02. Department of Mathematics; 04. Faculty of Science; 01. Izmir Institute of TechnologyWe first prove the infinitude of the primes via a special case of Rado's theorem whose proof is based on the infinite Ramsey theorem. In the proof, we use the colorings of the positive integers introduced by Levent Alpoge [1] and Andrew Granville [2]. Finally, using Rado's theorem for integral domains, we will give another proof for the infinitude of nonassociated prime elements in any unique factorization domain R with a few units.Article Citation - WoS: 1Citation - Scopus: 1Microporous Carbon Spheres for the Enrichment of Lead From Water Samples With Determination by Microsample Injection System - Flame Atomic Absorption Spectrometry (MIS-FAAS)(Taylor & Francis inc, 2025) Njjar, Muath; Ugan, Muhammet; Akturk, Ezgi Zekiye; Pelech, Iwona; Staciwa, Piotr; Akdogan, Abdullah; 01. Izmir Institute of TechnologyMicroporous carbon spheres (MCSs) are advanced materials known for their high surface area, well-developed pore structure, low density, and rapid molecular diffusion, making them highly effective in solid-phase extraction (SPE) and other applications. In this study, MCSs synthesized from previously reported resorcinol-formaldehyde resin were employed as an adsorbent for the extraction and preconcentration of Pb(II) ions. The material was comprehensively characterized to confirm its suitability for adsorption applications. The adsorption and desorption behavior of MCSs toward lead ions was systematically examined under optimized conditions, including pH, eluent volume, eluent type, eluent concentration, and sample volume. Microinjection microsample injection system-flame atomic absorption spectrometry (MIS-FAAS) was used for the determination of lead ions. Experimental results from batch experiments showed that the MCSs exhibited a maximum adsorption capacity of 37.31 mg g-1. Under optimal conditions (pH 8.0, 1.0 mL of 0.1 M HNO3 eluent, and 10 mg of adsorbent), a preconcentration factor of 100 was achieved, with recovery values exceeding 90%. The method exhibited a limit of detection (LOD) of 0.73 mu g L-1. The developed method was successfully applied to real water samples, including tap water, entering industrial wastewater, and exiting industrial wastewater, confirming its potential for use in environmental monitoring and contamination control.Article Rings Whose Mininjective Modules Are Injective(Taylor & Francis inc, 2025) Alagoz, Yusuf; Alagöz, Yusuf; Benli-Goral, Sinem; Büyükaşık, Engin; Buyukasik, Engin; Garcia Rozas, Juan Ramon; Oyonarte, Luis; 01. Izmir Institute of Technology; 04.02. Department of Mathematics; 04. Faculty of ScienceThe main goal of this paper is to characterize rings over which the mininjective modules are injective, so that the classes of mininjective modules and injective modules coincide. We show that these rings are precisely those Noetherian rings for which every min-flat module is projective and we study this characterization in the cases when the ring is Kasch, commutative and when it is quasi-Frobenius. We also treat the case of nxn upper triangular matrix rings, proving that their mininjective modules are injective if and only if n=2. We use the developed machinery to find a new type of examples of indigent modules (those whose subinjectivity domain contains only the injective modules), whose existence is known, so far, only in some rather restricted situations.