Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Article Citation - WoS: 27Citation - Scopus: 34Chitosan/Montmorillonite Composite Nanospheres for Sustained Antibiotic Delivery at Post-Implantation Bone Infection Treatment(IOP Publishing Ltd., 2019) Kımna, Ceren; Değer, Sibel; Tamburacı, Sedef; Tıhmınlıoğlu, FundaDespite the advancements in bone transplantation operations, inflammation is still a serious problem that threatens human health at the post-implantation period. Conventional antibiotic therapy methods may lead to some side effects such as ototoxicity and nephrotoxicity, especially when applied in high doses. Therefore, local drug delivery systems play a vital role in bone disorders due to the elimination of the disadvantages introduced by conventional methods. In the presented study, it was aimed to develop Vancomycin (VC) and Gentamicin (GC) loaded chitosan-montmorillonite nanoclay composites (CS/MMT) to provide required antibiotic doses to combat post-implantation infection. CS/MMT nanocomposite formation was supplied by microfluidizer homogenization and spherical drug carrier nanoparticles were obtained by electrospraying technique. Three factors; voltage, distance and flowrate were varied to fabricate spherical nanoparticles with uniform size. Emprical model was developed to predict nanosphere size by altering process variables. Nanospheres were characterized in terms of morphology, hydrodynamic size, zeta potential, drug encapsulation efficiency and release profile. Drug loaded nanospheres have been successfully produced with a size range of 180-350 nm. Nanocomposite drug carriers showed high encapsulation efficiency (80%-95%) and prolonged release period when compared to bare chitosan nanospheres. The drug release from nanocomposite carriers was monitored by diffusion mechanism up to 30 d. The in vitro release medium of nanospheres showed strong antimicrobial activity against gram-positive S. aureus and gram-negative E. coli bacteria. Furthermore, it was found that the nanospheres did not show any cytotoxic effect to fibroblast (NIH/3T3) and osteoblast (SaOS-2) cell lines. The results demonstrated that the prepared composite nanospheres can be a promising option for bone infection prevention at the post implantation period.Article Citation - WoS: 2Citation - Scopus: 3Can Tube Tunnel Crossings Relieve Urban Congestion Problems? Izmir Tube Tunnel Project Proposal Under Scrutiny(MDPI Multidisciplinary Digital Publishing Institute, 2019) Duvarcı, Yavuz; Yiğitcanlar, TanBuilding underwater tube tunnel crossings to ease the urban congestion problems has become a popular approach for many cities across the globe. London, New York, Istanbul, Hamburg, Sydney and Brisbane are among these cities. However, the effectiveness and externalities of these expensive mega urban infrastructures have also been questioned widely among urban, transport and environmental planning scholars. Given the international popularity of the topic, this study places a new tube tunnel crossings project from Izmir, Turkey under the microscope. In this heuristic simulation study, policy-on scenarios were tested to determine possible impacts of the underwater tube tunnel-crossing project. The traffic impacts are discussed using simulations assigning the initial origin-destination data. The results of the study revealed that, given the two locations, outer and inner locations over the dagger-shape bay, the capacity increments on the bridge links and the links around the periphery highway did not bring any effective solutions beyond some minor improvements. The findings disclosed that the ineffectiveness of the tube tunnel crossing might be due to the excessive congestion happening all over the downtown area, which clogs the passageways to the bridge. The paper highlights the limitations of the tube tunnel-crossing project, emphasises the need for comprehensive investigations before committing to the project and advocates the emphasis to be actually given for sustainable mobility.Article Citation - WoS: 2Citation - Scopus: 3Integrating Spatiotemporal Dynamics of Natural Capital Security and Urban Ecosystem Carbon Metabolism(Springer Verlag, 2018) Demirkesen, Ali Can; Evrendilek, FatihThe purpose of the study is to address and quantify the increase in urban expansion and carbon (C) metabolism burden on ecosystem service value (ESV), net ecosystem productivity (NEP), and C storage of urban footprint. Urban footprint is required to meet the demands arising from economic consumption and production as well as waste accumulation and assimilation. Spatiotemporal changes in main land covers (LCs) were detected using remotely sensed data (Landsat 5 and 8, and digital elevation model) between 1987 and 2016. Changes in ESV and C influx, efflux and pools associated with LC dynamics were approximated using global proxies for a western Mediterranean region in Turkey of 54,162 km2. Urban expansion over the 29-year period decreased ESV by 22% ($7.28 ± 0.4 billion), NEP by 4.3% (2.3 ± 9 Gg C), and total ecosystem C pool by 10.9% (1008.3 ± 1006 Gg C) and led to a 62.8% appropriation of the total NEP (50.1 ± 51 Gg C) of the urban footprint in 2016. The main cause of the environmental degradation across the study region was the loss of the seminatural areas. Our findings emphasize that the deterioration rate of ecosystems should be slowed down by natural capital-friendly decisions and should not exceed rehabilitation rate of damaged ecosystems in the face of rapidly increasing burdens of the cities on their footprint.Article Citation - WoS: 75Citation - Scopus: 74Scaffold-Free Three-Dimensional Cell Culturing Using Magnetic Levitation(Royal Society of Chemistry, 2018) Türker, Esra; Demirçak, Nida; Arslan Yıldız, AhuThree-dimensional (3D) cell culture has emerged as a pioneering methodology and is increasingly utilized for tissue engineering, 3D bioprinting, cancer model studies and drug development studies. The 3D cell culture methodology provides artificial and functional cellular constructs serving as a modular playground prior to animal model studies, which saves substantial efforts, time and experimental costs. The major drawback of current 3D cell culture methods is their dependency on biocompatible scaffolds, which often require tedious syntheses and fabrication steps. Herein, we report an easy-to-use methodology for the formation of scaffold-free 3D cell culture and cellular assembly via magnetic levitation in the presence of paramagnetic agents. To paramagnetize the cell culture environment, three different Gadolinium(iii) chelates were utilized, which led to levitation and assembly of cells at a certain levitation height. The assembly and close interaction of cells at the levitation height where the magnetic force was equilibrated with gravitational force triggered the formation of complex 3D cellular structures. It was shown that Gd(iii) chelates provided an optimal levitation that induced intercellular interactions in scaffold-free format without compromising cell viability. NIH 3T3 mouse fibroblasts and HCC827 non-small-cell lung cancer cells were evaluated via the magnetic levitation system, and the formation of 3D cell culture models was validated for both cell lines. Hereby, the developed magnetic levitation system holds promises for complex cellular assemblies and 3D cell culture studies.Article Citation - WoS: 46Citation - Scopus: 57Recent Advances in Magnetic Levitation: a Biological Approach From Diagnostics To Tissue Engineering(American Chemical Society, 2018) Türker, Esra; Arslan Yıldız, AhuThe magnetic levitation technique has been utilized to orientate and manipulate objects both in two dimensions (2D) and three dimensions (3D) to form complex structures by combining various types of materials. Magnetic manipulation holds great promise for several applications such as self-assembly of soft substances and biological building blocks, manipulated tissue engineering, as well as cell or biological molecule sorting for diagnostic purposes. Recent studies are proving the potential of magnetic levitation as an emerging tool in biotechnology. This review outlines the advances of newly developing magnetic levitation technology on biological applications in aqueous environment from the biotechnology perspective.Article Citation - WoS: 45Citation - Scopus: 45The First Countrywide Monitoring of Selected Pops: Polychlorinated Biphenyls (pcbs), Polybrominated Diphenyl Ethers (pbdes) and Selected Organochlorine Pesticides (ocps) in the Atmosphere of Turkey(Elsevier Ltd., 2018) Kurt Karakuş, Perihan Binnur; Ugranlı Çiçek, Tuğba; Sofuoğlu, Sait Cemil; Çelik, Halil; Güngörmüş, Elif; Gedik, Kadir; Sofuoğlu, Aysun; Ökten, Hatice Eser; Birgül, Aşkın; Alegria, Henry; Jones, Kevin C.Atmospheric levels of 43 PCBs, 22 OCPs, and 14 PBDEs were determined in 16 cities at urban and rural sites by passive sampling to generate the first large-scale nationwide dataset of POP residues in Turkey's atmosphere. Sampling campaign was performed from May 2014 to April 2015 with three-month sampling periods at locations on east-west and north-south transects through the country to investigate seasonal and spatial variations, including long range atmospheric transport (LRAT). Factor analysis was conducted to infer on the potential sources. Overall average Σ43PCBs concentration was 108 ± 132 pg/m3. PCB-118 (26.3 ± 44.6 pg/m3) was the top congener, and penta-CBs had the highest contribution with 54.3%. ΣDDTs had the highest annual mean concentration with 134 ± 296 pg/m3 among the OCP groups among which the highest concentration compound was p'p-DDE (97.6 ± 236 pg/m3). Overall average concentration of Σ14PBDEs was 191 ± 329 pg/m3 with the highest contribution from BDE-190 (42%). Comparison of OCPs and PCBs concentrations detected at temperatures which were above and below annual average temperature indicated higher concentrations in the warmer periods, hence significance of secondary emissions for several OCPs and Σ43PCBs, as well as inference as LRAT from secondary emissions. The first nationwide POPs database constructed in this study, point to current use, local secondary emissions, and LRAT for different individual compounds, and indicate the need for regular monitoring. The first country-wide passive sampling of selected POPs showed no unequivocal trends reflecting transitional location of Turkey.Article Citation - WoS: 3Citation - Scopus: 3A Quality Assessment of Public Water Fountains and Relation To Human Health: a Case Study From Yozgat, Turkey(John Wiley and Sons Inc., 2019) İritaş, Servet Birgin; Türksoy, Vugar Ali; Deniz, Serdar; Koçoğlu, Serhat; Kırat, Güllü; Demirkesen, Ali Can; Baba, AlperPublic fountains are very common and everyday people appreciate the benefits a water fountain can bring. However, consumption of public fountain water in some country has decreased because of growing concerns that constituents in fountain water may have adverse effects on health. A few studies have examined the safety of public fountains, proposing only limited evidence of fountain-related health issues in Turkey. Most of these public fountains are sourced from natural springs in Turkey. In this study, a 177 fountain water and 32 rock samples were analysed for source and quality of water. The geology of the region has the direct impact on the quality of the public fountain water. The results indicate that the level of some elements exceeded the limit values determined by WHO and US.EPA. The most striking high values were observed for iron (Fe), nickel (Ni), aluminum (Al), arsenic (As) and bromine (Br) concentrations.Article Citation - WoS: 18Citation - Scopus: 19Oxyhydroxide of Metallic Nanowires in a Molecular H2o and H2o2 Environment and Their Effects on Mechanical Properties(Royal Society of Chemistry, 2018) Aral, Gürcan; İslam, Md Mahbubul; Wang, Yun-Jiang; Ogata, Shigenobu; van Duin, Adri C. T.To avoid unexpected environmental mechanical failure, there is a strong need to fully understand the details of the oxidation process and intrinsic mechanical properties of reactive metallic iron (Fe) nanowires (NWs) under various aqueous reactive environmental conditions. Herein, we employed ReaxFF reactive molecular dynamics (MD) simulations to elucidate the oxidation of Fe NWs exposed to molecular water (H2O) and hydrogen peroxide (H2O2) environment, and the influence of the oxide shell layer on the tensile mechanical deformation properties of Fe NWs. Our structural analysis shows that oxidation of Fe NWs occurs with the formation of different iron oxide and hydroxide phases in the aqueous molecular H2O and H2O2 oxidizing environments. We observe that the resulting microstructure due to pre-oxide shell layer formation reduces the mechanical stress via increasing the initial defect sites in the vicinity of the oxide region to facilitate the onset of plastic deformation during tensile loading. Specifically, the oxide layer of Fe NWs formed in the H2O2 environment has a relatively significant effect on the deterioration of the mechanical properties of Fe NWs. The weakening of the yield stress and Young modulus of H2O2 oxidized Fe NWs indicates the important role of local oxide microstructures on mechanical deformation properties of individual Fe NWs. Notably, deformation twinning is found as the primary mechanical plastic deformation mechanism of all Fe NWs, but it is initially observed at low strain and stress level for the oxidized Fe NWs.Article Citation - WoS: 21Citation - Scopus: 27Exploring the Impact of External Shading System on Cognitive Task Performance, Alertness and Visual Comfort in a Daylit Workplace Environment(SAGE Publications Inc., 2019) Leccese, F.; Salvodori, G.; Öner, Merve; Kazanasmaz, Zehra TuğçeThe authors examined the effect of external shading system on cognitive performance, alertness and visual comfort of visual display terminal (VDT) users under two realistic office lighting settings in this study. Daylight was the source of illumination being considered as the most significant and preferred one. A total of 26 participants performed visual and cognitive demanding tasks as well as providing subjective alertness, performance and visual evaluations in a full-scale mock-up VDT workstation. Two trials (with and without shading system) were executed during one experimental session. Results revealed that the use of a shading system improves the performance of a user on colour-naming task requiring sustained attention, while no differential effects were observed on tasks involving other cognitive skills such as search velocity and vigilance. Within-subject performance differences were more pronounced during morning hours. Higher performance was reported in some cognitive tests when the subjective sensation of visual discomfort was lower.Article Citation - WoS: 2Citation - Scopus: 4Removal of Metals and Metalloids From Acidic Mining Lake (aml) Using Olive Oil Solid Waste (osw)(Springer Verlag, 2019) İlay, Remzi; Baba, Alper; Kavdır, YaseminThe acidic mining lakes have low pH values and high metal and metalloid concentrations. In this study, the ability of low-cost olive oil solid waste (OSW) to remove Al, As, Cd, Fe, B and Ti ions from aqueous solutions in short term has been evaluated. Adsorption capacities (mg g−1) of OSW (1:5–1:10 w/v) were 764.06–411.75 for Al, 0.26 for As, 0.07–0.14 for Cd, 2181.5–2406.5 for Fe, 23.70–82.50 for B and 0.12–0.0.34 for Ti. OSW addition increased acidic mine water (AMW) pH from 2.41 to 3.2 with 1:5 and from 2.41 to 2.7 to 1:10 mixing ratio, respectively, after 10 min. The best gradual decrease has been observed with different ratio of OSW applications on B and Ti concentrations. OSW adsorbs 32.41% and 62.68% of B at the ratio of 1:5 and 1:10 and 55.29% and 83.04% of Ti at the ratio of 1:5 and 1:10 (OSW:AMW) mixtures, respectively. The results show that OSW has great potential for metal removal from acidic mine water.