Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 2Citation - Scopus: 4Injectable Nanocomposite Hydrogels With Co-Delivery of Oxygen and Anticancer Drugs for Higher Cell Viability of Healthy Cells Than Cancer Cells Under Normoxic and Hypoxic Conditions(Iop Publishing Ltd, 2025) Kehr, Nermin SedaInjectable nanocomposite hydrogels (NC hydrogels) have the potential to be used for minimally invasive local drug delivery. In particular, pH-sensitive injectable NC hydrogels can be used in cancer treatment to deliver high doses of anticancer drugs to the target site in cancer tissue without damaging healthy tissue. Recent studies have shown that in addition to stimuli-responsive delivery of anticancer drugs to cancer cells, oxygen delivery to the hypoxic environment of cancer tissue can lead to advanced effects, as hypoxia and an acidic pH are common characteristics of cancer tissue. However, few studies have investigated the effects of simultaneous administration of oxygen (O2) and pH-dependent anticancer drugs via injectable NC hydrogels on the viability of healthy and cancer cells under normoxic and hypoxic conditions. In this context, we describe the synthesis of injectable NC hydrogels composed of pH-responsive nanomaterials carrying oxygen and anticancer drugs. Our system provides sustained O2 release and pH-responsive sustained release of anticancer drugs for 15 and 30 d, respectively. Moreover, O2 delivery and/or simultaneous delivery of O2 and anticancer drug resulted in higher cell survival of healthy fibroblast cells than malignant Colo-818 cells under hypoxic conditions (1% O2) after 7 d of incubation.Review Citation - WoS: 1Citation - Scopus: 1Colloidal Quantum Dots as Solution-Based Nanomaterials for Infrared Technologies(Iop Publishing Ltd, 2024) Sevim Ünlütürk, S.; Taşcıoğlu, D.; Özçelik, S.This review focuses on recent progress of wet-chemistry-based synthesis methods for infrared (IR) colloidal quantum dots (CQD), semiconductor nanocrystals with a narrow energy bandgap that absorbs and/or emits IR photos covering from 0.7 to 25 micrometers. The sections of the review are colloidal synthesis, precursor reactivity, cation exchange, doping and de-doping, surface passivation and ligand exchange, intraband transitions, quenching and purification, and future directions. The colloidal synthesis section is organized based on precursors employed: toxic substances as mercury- and lead-based metals and non-toxic substances as indium- and silver-based metal precursors. CQDs are prepared by wet-chemical methods that offer advantages such as precise spectral tunability by adjusting particle size or particle composition, easy fabrication and integration of solution-based CQDs (as inks) with complementary metal-oxide-semiconductors, reduced cost of material manufacturing, and good performances of IR CQD-made optoelectronic devices for non-military applications. These advantages may allow facile and materials' cost-reduced device fabrications that make CQD based IR technologies accessible compared to optoelectronic devices utilizing epitaxially grown semiconductors. However, precursor libraries should be advanced to improve colloidal IR quantum dot synthesis, enabling CQD based IR technologies available to consumer electronics. As the attention of academia and industry to CQDs continue to proliferate, the progress of precursor chemistry for IR CQDs could be rapid. © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.Article Citation - WoS: 3Citation - Scopus: 6Large-Area (50 Cm X 50 Cm) Optically Transparent Electromagnetic Interference (emi) Shielding of Zto/Ag an Analytical/Numerical and Experimental Study of Optoelectrical and Emi Shielding Properties(Iop Publishing Ltd, 2024) Astarlioglu, Aziz Taner; Oz, Yahya; Unal, Emre; Kilic, Nail Bugra; Celikli, Cenkay; Ozdemir, Mehtap; Erdogan, NursevTransparent conducting oxides (TCOs), exhibiting both high optical transparency and low electrical resistivity, are commonly employed in optoelectronic devices. However, acquiring a balance between these optical and electrical properties in a uniform way over large areas has been a pending challenge, which is essential to achieving optically transparent electromagnetic interference (EMI) shielding surfaces. In this study, we propose and demonstrate a stratified thin film structure consisting of zinc-doped tin oxide (Zn2SnO4, ZTO) as TCO along with a metal layer of silver (Ag) deposited on a large area of 50 cm x 50 cm polycarbonate (PC) substrate enabled by a scanning magnetron sputtering gun. We achieved high EMI shielding of 99.9% at the optical transparency of 68% in the visible spectrum by engineering the stratified architecture of ZTO/Ag/ZTO. The Ag layer of 18 nm in thickness with a sheet resistance of 10 Omega/sq yields shielding effectiveness (SE) of 27 dB in a wide frequency range of 2-20 GHz. The bottom and top ZTO layers, 20 and 40 nm thick, respectively, provide the lowest optical loss of 13% across 400-700 nm. The structure's EMI shielding, optical and structural performances were systematically characterized through a free-space focused-beam system, UV-Vis spectrophotometer, ellipsometry, focused ion-beam cross-sectional sampling and imaging, transmission electron microscopy, atomic force microscopy and secondary ion mass spectroscopy. EMI shielding and optical performances were validated by CST Microwave Studio and the transfer matrix method, respectively. These findings indicate that the proposed multi-layer architecture holds great promise for large-area EMI shielding and other optoelectronic applications.Article Citation - WoS: 3Citation - Scopus: 4Patient-Specific Finite Element Analysis for Assessing Hip Fracture Risk in Aging Populations(Iop Publishing Ltd, 2024) Chethan, K. N.; Waldschmidt, Nadine Schmidt Genannt; Corda, John Valerian; Shenoy, Satish B.; Shetty, Sawan; Keni, Laxmikant G.; Mihcin, SenayThe femur is one of the most important bone in the human body, as it supports the body's weight and helps with movement. The aging global population presents a significant challenge, leading to an increasing demand for artificial joints, particularly in knee and hip replacements, which are among the most prevalent surgical procedures worldwide. This study focuses on hip fractures, a common consequence of osteoporotic fractures in the elderly population. To accurately predict individual bone properties and assess fracture risk, patient-specific finite element models (FEM) were developed using CT data from healthy male individuals. The study employed ANSYS 2023 R2 software to estimate fracture loads under simulated single stance loading conditions, considering strain-based failure criteria. The FEM bone models underwent meticulous reconstruction, incorporating geometrical and mechanical properties crucial for fracture risk assessment. Results revealed an underestimation of the ultimate bearing capacity of bones, indicating potential fractures even during routine activities. The study explored variations in bone density, failure loads, and density/load ratios among different specimens, emphasizing the complexity of bone strength determination. Discussion of findings highlighted discrepancies between simulation results and previous studies, suggesting the need for optimization in modelling approaches. The strain-based yield criterion proved accurate in predicting fracture initiation but required adjustments for better load predictions. The study underscores the importance of refining density-elasticity relationships, investigating boundary conditions, and optimizing models through in vitro testing for enhanced clinical applicability in assessing hip fracture risk. In conclusion, this research contributes valuable insights into developing patient-specific FEM bone models for clinical hip fracture risk assessment, emphasizing the need for further refinement and optimization for accurate predictions and enhanced clinical utility.Article Citation - WoS: 4Citation - Scopus: 4Ultra-Thin Double-Layered Hexagonal Cui: Strain Tunable Properties and Robust Semiconducting Behavior(Iop Publishing Ltd, 2024) Demirok, A. C.; Sahin, H.; Yagmurcukardes, M.In this study, the freestanding form of ultra-thin CuI crystals, which have recently been synthesized experimentally, and their strain-dependent properties are investigated by means of density functional theory calculations. Structural optimizations show that CuI crystallizes in a double-layered hexagonal crystal (DLHC) structure. While phonon calculations predict that DLHC CuI crystals are dynamically stable, subsequent vibrational spectrum analyzes reveal that this structure has four unique Raman-active modes, allowing it to be easily distinguished from similar ultra-thin two-dimensional materials. Electronically, DLHC CuI is found to be a semiconductor with a direct band gap of 3.24 eV which is larger than that of its wurtzite and zincblende phases. Furthermore, it is found that in both armchair (AC) and zigzag (ZZ) orientations the elastic instabilities occur over the high strain strengths indicating the soft nature of CuI layer. In addition, the stress-strain curve along the AC direction reveal that DLHC CuI undergoes a structural phase transition between the 4% and 5% tensile uniaxial strains as indicated by a sudden drop of the stress in the lattice. Moreover, the phonon band dispersions show that the phononic instability occurs at much smaller strain along the ZZ direction than that of along the AC direction. Furthermore, the external strain direction can be deduced from the predicted Raman spectra through the splitting rates of the doubly degenerate in-plane vibrations. The mobility of the hole carriers display highly anisotropic characteristic as the applied strain reaches 5% along the AC direction. Due to its anomalous strain-dependent electronic features and elastically soft nature, DLHC of CuI is a potential candidate for future electro-mechanical applications.Article Citation - WoS: 3Citation - Scopus: 4Cost-Effective Experiments With Additively Manufactured Waveguide and Cavities in the S-Band(Iop Publishing Ltd, 2023) Karatay, Anıl; Yilmaz, Hasan Önder; Özkal, Ceren; Yaman, FatihThis study demonstrates the applicability of additively manufactured components that are metalized with conductive tape for two different microwave experiments. We focus on dielectric measurements and prototyping elliptical accelerator cavities at a low power regime for 2.45 GHz. To illustrate the accuracy of our results for the commonly used solid/liquid materials in engineering and to compare the fundamental accelerator cavity parameters with previous research rectangular and elliptic 3D-printed cavities coated with aluminum-type tape were employed in the experiments. Results reported for the complex-valued permittivities and specific design parameters for the cavity prototype are consistent with the literature. Various approaches to obtain the conductivity value of the tape and the effect of the roughness/thickness of the coating on the reflection parameter are discussed in detail. We confirm the effectiveness of the proposed approach, which reduces costs and provides a high degree of accuracy for investigated applications.