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: 13Citation - Scopus: 13Her2-Targeted, Degradable Core Cross-Linked Micelles for Specific and Dual Ph-Sensitive Dox Release(John Wiley and Sons Inc., 2021) Bayram, Nazende Nur; Ulu, Gizem Tuğçe; Topuzoğulları, Murat; Baran, Yusuf; Dinçer İşoğlu, SevilHere, a targeted, dual-pH responsive, and stable micelle nanocarrier is designed, which specifically selects an HER2 receptor on breast cancer cells. Intracellularly degradable and stabilized micelles are prepared by core cross-linking via reversible addition-fragmentation chain-transfer (RAFT) polymerization with an acid-sensitive cross-linker followed by the conjugation of maleimide-doxorubicin to the pyridyl disulfide-modified micelles. Multifunctional nanocarriers are obtained by coupling HER2-specific peptide. Formation of micelles, addition of peptide and doxorubicin (DOX) are confirmed structurally by spectroscopical techniques. Size and morphological characterization are performed by Zetasizer and transmission electron microscope (TEM). For the physicochemical verification of the synergistic acid-triggered degradation induced by acetal and hydrazone bond degradation, Infrared spectroscopy and particle size measurements are used. Drug release studies show that DOX release is accelerated at acidic pH. DOX-conjugated HER2-specific peptide-carrying nanocarriers significantly enhance cytotoxicity toward SKBR-3 cells. More importantly, no selectivity toward MCF-10A cells is observed compared to HER2(+) SKBR-3 cells. Formulations cause apoptosis depending on Bax and Caspase-3 and cell cycle arrest in G2 phase. This study shows a novel system for HER2-targeted therapy of breast cancer with a multifunctional nanocarrier, which has higher stability, dual pH-sensitivity, selectivity, and it can be an efficient way of targeted anticancer drug delivery.Article Citation - WoS: 4Citation - Scopus: 5Social Capital and Regional Development in Turkey(John Wiley and Sons Inc., 2020) Arslan, Hüseyin Mert; Duran, Hasan EnginThis paper aims to improve the shortcomings of the empirical literature on regional social capital. The following three research questions are addressed: (i) do regional social capital and economic growth have an endoneous (circular) relationship as opposed to the exogenous one-way relationship assumed in the literature; (ii) What are the socio-economic and demographic determinants of cross-regional variation in social capital? And (iii) Are spatial spillovers relevant in the analysis of these questions? Empirically, we pursue the analysis for 81 Turkish provinces in 2015. Indeed, regional social capital in Turkey is far less studied than country-level social capital. The methodology adopted includes kernel density estimates, ordinary least squares, three stage least squares, and spatial error models. In terms of the obtained results, First, regional social capital is heterogenously distributed across regions. Second, social capital has no significant impact on economic growth but the growth induces the generation of social capital (in social norms). This represents a first result of reserve causality in the literature. Third, a typical province that has high social capital is the one with relatively high income, more even income distribution, low unemployment, big households and older age profile. Fourth, there is the evidence of spatial dependence that should be incorporated in empirical analyses.Article Citation - WoS: 22Citation - Scopus: 24Scaffold-Free Biofabrication of Adipocyte Structures With Magnetic Levitation(John Wiley and Sons Inc., 2021) Sarıgil, Öykü; Yalçın Özuysal, Özden; Anıl İnevi, Müge; Meşe Özçivici, Gülistan; Fıratlıgil Yıldırır, Burcu; Fıratlıgil Yıldırır, Burcu; Ünal, Yağmur Ceren; Ünal, Yağmur Ceren; Yalçın Özuysal, Özden; Özçivici, Engin; Meşe, Gülistan; Sarıgil, Öykü; Özçivici, Engin; Anıl İnevi, Müge; Meşe Özçivici, GülistanTissue engineering research aims to repair the form and/or function of impaired tissues. Tissue engineering studies mostly rely on scaffold-based techniques. However, these techniques have certain challenges, such as the selection of proper scaffold material, including mechanical properties, sterilization, and fabrication processes. As an alternative, we propose a novel scaffold-free adipose tissue biofabrication technique based on magnetic levitation. In this study, a label-free magnetic levitation technique was used to form three-dimensional (3D) scaffold-free adipocyte structures with various fabrication strategies in a microcapillary-based setup. Adipogenic-differentiated 7F2 cells and growth D1 ORL UVA stem cells were used as model cells. The morphological properties of the 3D structures of single and cocultured cells were analyzed. The developed procedure leads to the formation of different patterns of single and cocultured adipocytes without a scaffold. Our results indicated that adipocytes formed loose structures while growth cells were tightly packed during 3D culture in the magnetic levitation platform. This system has potential for ex vivo modeling of adipose tissue for drug testing and transplantation applications for cell therapy in soft tissue damage. Also, it will be possible to extend this technique to other cell and tissue types.Article Citation - WoS: 2Citation - Scopus: 2Regional Inflation Persistence in Turkey(John Wiley and Sons Inc., 2021) Duran, Hasan Engin; Dindaroğlu, BurakThe purpose of the current study is to investigate the degree of inflation persistence, its geographical variation, sources of cross-regional variation, and presence of geographical/sectoral aggregation bias in national monetary policy. Our data set covers 26 NUTS-2 level Turkish regions and monthly CPI inflation over the period 2003-2019. We first estimate the degree of regional inflation persistence by autoregressive regressions, check its robustness against the presence of structural breaks (by Bai-Perron's algorithm) and nonlinearities (by Markovian Regime Switching regressions). Second, we examine the possibility of geographical and sectoral aggregation bias. Third, we investigate the cross-regional determinants of inflation persistence by panel data analysis, employing hybrid-effects spatial panel regressions. We analyze the direct and indirect effects of the determinants and test for regional spillover effects. Three main results are obtained. First, estimated persistence degrees are heterogeneous across regions. The geographical pattern is empirically robust against structural breaks and nonlinearities. We find that inflation persistence is distributed in a spatially correlated manner. Second, when sectoral and regional aggregation bias is tested, only sectoral aggregation indicates a considerable level of bias. Third, we find that the presence of large firms in the region and a higher share of agricultural output in GDP leads to lower persistence, while an increased share of industrial output, and increased trade volume leads to higher inflation persistence. Moreover, we find spatial spillovers of price variability evident in regression analysis. From a policy standpoint, it is required that structural policy programs are targeted to maintain flexibility in the regions where persistence is high (i.e., providing market entry/exit, institutional quality, policy credibility, stimulation of SMEs). Moreover, sectors that have high persistence, such as Hotels and Restaurants (persistence degree 0.55) and Health Services (0.39) should be weighted more in CPI calculations.Article Citation - WoS: 20Citation - Scopus: 25Experimental Investigation on Reinforced Concrete Slabs Strengthened With Carbon Textiles Under Repeated Impact Loads(John Wiley and Sons Inc., 2020) Batarlar, Baturay; Hering, M.; Bracklow, F.; Kühn, T.; Beckmann, B.; Curbach, M.This study presents the performance of carbon textile reinforcement used as strengthening layers for reinforced concrete (RC) slabs under repeated impact loads. In order to reveal the contribution of carbon textile reinforcement to the behavior of RC slabs under impacts, five identical RC slabs with the dimensions of 1.5 m × 1.5 m × 0.20 m were manufactured and tested at the Technische Universität Dresden. To understand failure mechanisms of RC slabs under impact loadings, two specimens were kept unstrengthened and tested under different impact velocities. The rest of the specimens was strengthened with three different carbon textile reinforcements embedded in an additional 2 cm fine-grained concrete layer and subjected to impact loads with the same striker velocity. The results observed from the tests revealed that the carbon textile reinforcement is very effective at increasing the impact capacities of the specimens. Additionally, displacement–time histories and crack profiles are highly affected due to the carbon textile reinforcement types and ratios during the impact loadings. © 2020 The Authors. Structural Concrete published by John Wiley & Sons Ltd on behalf of International Federation for Structural Concrete.Article Citation - WoS: 18Citation - Scopus: 22A Review of Heat and Fluid Flow Characteristics in Microchannel Heat Sinks(John Wiley and Sons Inc., 2020) Coşkun, Turgay; Çetkin, ErdalHeat transfer and flow characteristic in microchannel heat sinks (MCHS) are extensively studied in the literature due to high heat transfer rate capability by increased heat transfer surface area relative to the macroscale heat sinks. However, heat transfer and fluid flow characteristics in MCHS differ from conventional ones because of the scaling effects. This review summarizes the studies that are mainly based on heat transfer and fluid flow characteristic in MCHS. There is no consistency among the published results; however, everyone agrees on that there is no new physical phenomenon in microscale that does not exist at macroscale. Only difference between them is that the effect of some physical phenomena such as viscous dissipation, axial heat conduction, entrance effect, rarefaction, and so forth, is negligibly small at macroscale, whereas it is not at microscale. The effect of these physical phenomena on the heat transfer and flow characteristics becomes significant with respect to specified conditions such as Reynolds number, Peclet number, hydraulic diameter, and heat transfer boundary conditions. Here, the literature was reviewed to document when these physical phenomena become significant and insignificant.Article Citation - WoS: 69Citation - Scopus: 77Novel Zein-Based Multilayer Wound Dressing Membranes With Controlled Release of Gentamicin(John Wiley and Sons Inc., 2019) Kimna, Ceren; Tamburacı, Sedef; Tıhmınlıoğlu, FundaRecently, functional multilayer scaffolds with controlled drug release ability come into prominence for wound healing applications to mimic the layered structure of skin tissue and prevent the possible infections at the defect site. In this study, controlled antibiotic releasing zein bilayer membranes were fabricated for treatment of acute skin infections. Gentamicin loaded fibers were prepared by electrospinning on the membrane surface. Membranes were characterized with scanning electron microscope, atomic force microscopy, Fourier transform infrared spectroscopy, contact angle, mechanical analysis, swelling, degradation, and water vapor permeability studies. In vitro cytotoxicity, cell attachment, and proliferation were investigated. Cell attachment on fiber layer was observed with fluorescence imaging. Fabricated fibers showed structural similarity to the skin tissue layers with a fiber diameter range of 350-425 nm and film thickness in the range of 311-361 mu m. Mechanical properties were found compatible with the skin tissue. In addition, membranes showed antimicrobial activity against Staphylococcus aureus and Escherichia coli. The sustained release was achieved with a cumulative release of 94%. Membranes did not show any cytotoxic effect. NIH/3T3 and HS2 cell lines were proliferated on each layer mimicking the multilayer skin tissue. Hence, zein-based bilayer membrane showed promising properties to be used as a potential antimicrobial wound dressing for skin tissue regeneration. (c) 2018 Wiley Periodicals, Inc.Article Citation - WoS: 106Citation - Scopus: 123A Review of Current and Future Food Applications of Natural Hydrocolloids(John Wiley and Sons Inc., 2020) Yemenicioğlu, Ahmet; Farris, Stefano; Türkyılmaz, Meltem; Güleç, ŞükrüThe main aim of this review paper was to focus on current and potential future sources and food applications of natural hydrocolloids in the food industry. The emerging research trends, problems, new methods and alternative approaches in production, environmental concerns, market trends and newly discovered health benefits have been discussed for natural hydrocolloids of commercial relevance. The rheological and surface active properties, interactions, functional properties, films and coatings, encapsulation applications and nanotechnology uses of natural hydrocolloids have been discussed in the light of recent developments. This review also reflected the most up-to-date concepts of applying natural hydrocolloids to meet consumer's and food sector's sophisticated demands related to food products.Article Citation - WoS: 3Citation - Scopus: 4Impact Loading and Modelling a Multilayer Aluminium Corrugated/Fin Core: the Effect of the Insertion of Imperfect Fin Layers(John Wiley and Sons Inc., 2019) Sarıkaya, Mustafa; Taşdemirci, Alper; Güden, MustafaThe quasi-static compression (0.0048 m/s) and Taylor-like impact (135, 150, and 200 m/s) loading of a multilayer 1050 H14 aluminium corrugated core were investigated both experimentally and numerically in LS-DYNA using the perfect and imperfect sample models. In the imperfect sample models, one or two layers of corrugated fin structure were replaced by the fin layers made of bent-type cell walls. The localised deformation in the quasi-static imperfect models of cylindrical sample started at the imperfect layers, the same as the tests, and the layers were compressed until about the densification strain in a step-wise fashion. The localised deformation in the perfect models, however, started at the layers at and near the top and bottom of the test sample. In the shock mode, the sample crushed sequentially starting at the impact end layer regardless the perfect or imperfect sample models were used. Furthermore, the perfect and imperfect models resulted in nearly the same initial crushing stresses in the shock mode. The layer strain histories revealed a velocity-dependent layer densification strain. Both model types, the imperfect and perfect, well approximated the stress-time histories and layer deformations of the shock mode. The rigid perfectly plastic locking model based on the numerically determined densification strains also showed well agreements with the experimental and numerical plateau stresses of the shock mode.Article Citation - WoS: 9Citation - Scopus: 9Modification of Commercial Boron Carbide Powder Using Rapid Carbothermal Reduction(John Wiley and Sons Inc., 2019) Toksoy, Muhammet Fatih; Haber, Richard A.Non-uniform morphology and existence of free carbon are two main problems for commercial boron carbide powders. This work proposes a method for eliminating free carbon and changing the morphology of commercial powders using Rapid Carbothermal Reduction (RCR) process. Free carbon is eliminated from commercial boron carbide powders and morphology is evolved to less angular shapes with limited particle size growth. Commercial and modified powders were densified by Spark Plasma Sintering at 1900 degrees C with 0, 5, and 20 minutes dwell. Despite the particle size growth, modified boron carbide powders reached >99% TD with shorter dwell times compared with commercial starting powders. Improved microhardness observed with dense modified samples as a result of enhanced morphology and increased twinning.