IYTE GCRIS Database (Izmir Institute of Technology)
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Enhancing Visible Light Photocatalytic Activity of Holmium Doped G-C3n4 and Dft Theoretical Insights
No full textIn the search of novel photocatalysts to increase the effect of visible light in photocatalysis, g-C3N4 (CN) has become a shining star. Rare earth metals have been used as dopant material to reinforce the photocatalytic activity of CN due to their unique electron configuration recently. In this present study, the pure and different amounts of Ho-doped g-C3N4 (HoCN) photocatalysts were successfully synthesized using urea as a precursor by the one-pot method. Morphological, structural, optical, and vibrational properties of the synthesized photocatalysts were characterized by SEM, EDX, XRD, TGA, XPS, FTIR, PL, TRPL, Raman, DRS, and BET analyses. In addition, theoretical calculations using density functional theory (DFT) were meticulously carried out to delve the changes in the structural and electronic structure of CN with holmium doping. According to calculations, the chemical potential, electrophilicity, and chemical softness are higher for HoCN, while HOMO–LUMO gap, dipole moment, and the chemical hardness are lower for the pure one. Thus, holmium doping becomes desirable with low chemical hardness which indicates more effectivity and smaller HOMO–LUMO gap designate high chemical reactivity. To determine the photocatalytic efficiency of the pure and doped CN photocatalysts, the degradation of methylene blue (MB) was monitored under visible light. The results indicate that holmium doping has improved the photocatalytic activities of CN samples. Most strikingly, this improvement is noticeable for the 0.2 mmol doped CN sample that showed two times better photocatalytic activity than the pure one. © The Author(s) 2024
Treatment With Recombinant Human Lysosomal Sshexosaminidase Reduces Gm2 Accumulation in Tay-Sachs Disease Cells
No full text[No Abstract Available
Physical and Numerical Investigation of Flip Anchors
No full textThe tensile capacity of driven earth anchors is important in maintaining slope stability. This study aims to summarize the results of field pull-out experiments conducted on two types of driven earth anchors that were installed in three different soil layers. The galvanized cast steel material was used in the construction of driven earth anchors. The large driven earth anchor (FPA-I) weighed 10 kg, while the small driven earth anchor (FPA-II) weighed approximately 5 kg. The FPA-I anchor was initially driven vertically into the clayey sand layer at a depth of 1.5 m, followed by the silty sand layer at a depth of 2.5 m, and ultimately the low-plastic clay layer at a depth of 3.25 m. FPA-II anchor was then driven vertically to a depth of 1.5 m and 2.5 m. The flip anchor heads were then rotated to allow sufficient earth pressure to act on them. Pull-out tests determined the maximum tensile resistance of two differently designed flip anchors at different depths. The flip anchors were then modeled using a commercially available finite element program (PLAXIS-2D) based on the data obtained from the field pull-out tests, and the ultimate tensile resistances obtained from the field were used as the applied tensile load values for the numerical analysis. As a result of the numerical analysis, both displacements and total principal stresses were obtained at the top and bottom of the soil surrounding the flip anchors. The main findings from the field tests and numerical analysis results are that the behavior of flip anchors exhibit different behavior in each soil profile and is affected by the principal stress and displacement in the soil profile near the surface.Darbeli zemin ankrajlarının çekme kapasitesinin anlaşılması, şev stabilitesinin korunması açısından çok önemlidir. Bu çalışma, üç farklı zemin tabakasına sürülen iki farklı darbeli zemin ankrajının sahada yapılan çekme testlerinden elde edilen bulguları sunmayı amaçlamaktadır. Her iki ankrajın yapımında da galvanizli çelik döküm malzeme kullanılmıştır. Büyük darbeli zemin ankrajı (FPA-I) ağırlığı 10 kg, küçük darbeli zemin ankrajı (FPA-II) ağırlığı ise yaklaşık 5 kg'dır. FPA-I, önce 1.5 metre derinlikteki killi kum kum tabakasına, ardından 2.5 metre derinlikteki siltli kum tabakasına ve son olarak 3,25 metre derinlikteki düşük plastisiteli kil tabakasına dikey olarak sürüldü. Daha sonra, FPA-II ankrajı dikey olarak 1.5 metre ve 2.5 metre derinliğine kadar sürüldü. Darbeli zemin ankrajı yeterli toprak basıncının üzerlerine etki etmesine izin verecek şekilde döndürüldü. Çekme testleri ile farklı derinliklerdeki iki farklı tasarıma sahip darbeli zemin ankrajının maksimum çekme direnci belirlendi. Darbeli zemin ankrajları daha sonra saha testlerinden elde edilen verilere dayalı olarak piyasada bulunan bir sonlu elemanlar programı (PLAXIS-2D) kullanılarak modellenmiş ve sahadan elde edilen nihai çekme dayanımları sayısal analiz için uygulanan çekme yükü değerleri olarak kullanılmıştır. Sayısal analiz sonucunda, darbeli zemin ankrajlarını çevreleyen zeminin üst ve alt kısımlarında hem yer değiştirmeler hem de toplam asal gerilmeler elde edilmiştir. Saha deneylerinden ve sayısal analiz sonuçlarından elde edilen ana bulgular, darbeli zemin ankrajlarının çekme davranışının her zemin profilinde farklı davranış sergilediği ve yüzeye yakın zemin profilindeki asal gerilme ve yer değiştirmeden etkilendiği sonucuna varılmıştır
Proliferative Effects and Cellular Uptake of Ceramic Nanoparticles in Cancer and Normal Cells
No full textThe high biocompatibility, wear resistance, and high surface area-to-volume ratios of calcium phosphate (CaP) nanoparticles make them materials of great interest for a very broad range of medical applications, such as dentistry, drug delivery, biomedical imaging, gene transfection and silencing, biomedical imaging, immunisation, and bone substitution. While their use as an enamel remineralisation agent, a bone substitution material, an implant coating, and drug/gene delivery agents is widely approved by the regulating bodies, insufficient attention has been paid to the interactions of CaP-based nanoparticles with cells and organs once in the bloodstream and distributed through the body. Here, three different CaP-based nanoparticles (CP: calcium phosphate, TCP: tricalcium phosphate, and HAp: hydroxyapatite) were examined for the proliferative effects, oxidative damage potential, and cellular uptake in the human embryonic kidney (HEK293) and pancreatic cancer (Panc-1) cell lines. The physicochemical properties of the nanoparticles were characterised by Teller analysis, and X-ray diffraction spectroscopy. Maximum proliferative effects were generated by 400 mu g center dot ml-1 TCP (220 %) in HEK293 cells. Interestingly, although CP nanoparticles had the highest reactive oxygen species formation capacity in the HEK293 cells, they exhibited the lowest proliferative effects and a relatively low internalisation rate, suggesting a minimal correlation between the cellular uptake level and oxidative potential
Exploring Noncentrifugal Sugar as a Partial Replacement for White Sugar in Low Methoxyl Pectin Confectionery Gels: Impacts on Physical and Rheological Properties
No full textNoncentrifugal sugar (NCS) is an unrefined, dark brown sugar containing minerals and plant secondary metabolites, unlike refined white sugar (WS). This study explored using NCS in confectionary jellies as an alternative sugar. We used different concentrations of NCS and WS to prepare low methoxyl pectin (LMP) confectionery gels characterized by their physical and rheological properties along with time-domain nuclear magnetic resonance (TD-NMR) relaxometry. The strongest LMP gel, with a hardness of 0.94 N, was achieved by substituting 25% of WS with NCS at a low CaCl2 concentration (0.075 M). Gels with up to 50% WS replaced by NCS showed comparable hardness to standard LMP gels made solely with WS at a 0.15 M CaCl2 concentration, attributed to NCS's unique constituents. The NCS-WS gel exhibited the shortest T2 values (139.8 ms) and self-diffusion coefficient values (4.99 x 10-10 m2/s), indicating a denser, more cross-linked structure that restricted water mobility. These findings suggest NCS's complex role in affecting LMP gels' chemical and physical properties, highlighting its potential as a partial WS replacement in LMP gelation-based products, with an additional source of minerals and antioxidants
Engineering a Novel Cyp119 With High Biocatalytic Efficiency by Optimization of Protein Interactions and Electron Transfer
No full textSitokrom P450 enzimleri, birçok biyoteknolojik uygulama için mükemmel bir seçimdir. P450 sistemlerinin daha geniş uygulamalarını sınırlayan çeşitli zaafları vardır; redoks partner proteinleri yoluyla NAD(P)H'den elektron transferine duyulan ihtiyaç nedeniyle bu sistemlerin karmaşıklığı, NAD(P)H oksidasyonu ile ürün oluşumu arasındaki kopukluk gibi. Yüksek aktiviteye sahip rekombinant P450 enzim sistemleri, optimum redoks partnerleri seçilerek, bölgeye yönelik mutajenez kullanılarak veya farklı redoks ortakları denenerek elde edilebilir. P450'ler arasında ısıya dayanıklı asidotermofilik Sulfolobus acidocaldarius arkesinden elde edilen CYP119 enziminin biyokatalizör olarak potansiyeli yüksektir. Bu çalışmada, elektron transfer partneri, putidaredoxin (Pdx) ve termofilik CYP119 enzimi arasındaki protein-protein etkileşim incelenmiş ve rasyonel tasarımla elektron transfer verimliliği iyileştirilmiştir. On dört çeşit mutantlar tasarımı, PyRosetta Yazılımı kullanılarak, Rosie Docking Server ile docking yapıldı. Elde edilen sonuçlara göre, deneysel işlemler için N34E, D77R, N34E-D77R mutasyonları seçildi. CYP119 ve N34E, N34E-D77R ve D77R mutantların laurık asitle bağlanmasının ayrışma sabitleri (Kd) fark spektroskopisi ile 19 µM, 35 µM, 23 µM ve 87 µM olarak belirlendi. CYP119 için Pdx bağlanmasına ilişkin literaturde bildirilen Kd değeri 2100 µM. CYP119 ve N34E, N34E-D77R ve D77R mutantların Pdx ile bağlanmasının fark spektroskopisi ayrışma sabitleri ise 2440 µM, 112 µM, 200 µM ve 797 µM değerleri olarak gözlemledi. Böylece N34E mutasyonunda elektron transfer hızı 21 kat, N34E-D77R mutasyonunda ise 12 kat artıyor. D77R mutasyonu Koo (2002) tarafından önerildigi gibi bağlanmada yaklaşık 4 kat artışı doğruladı. Bu sonuçlar N34E ve N34E-D77R mutasyonlarının Pdx'e daha yüksek afiniteyle bağlandığına dair doğrudan kanıt sağlar. Bu CYP119-Pdx-PdR sisteminde elektron transfer hızında artış sağlar.Cytochrome P450s are the perfect choice for many biotechnological applications. The requirement for costly electron donors (NAD(P)H), redox partners, and uncoupling, the process of formation of reactive oxygen species instead of desired products, are limitations of P450s' extensive utilization. By selecting the best redox partners, and utilizing site-directed mutagenesis to improve protein-protein interaction, a novel P450 enzyme with increased activity can be obtained. Thermophilic CYP119 obtained from Sulfolobus acidocaldarius has a high potential as biocatalyst. In the current research, protein-protein interaction between electron transfer partner of P450cam, putidaredoxin (Pdx) and CYP119 was examined and their electron transfer efficiency was improved by rational design. Using PyRosetta Software, 14 mutants were created, using Rosie Docking Server, docking analysis were performed. The best models, N34E, D77R and N34E-D77R mutations were performed with site-directed mutagenesis method. Difference spectroscopy of substrate (lauric acid) binding to WT and mutant CYP119 revealed Kd values of 19 µM, 35 µM, 23 µM and 87 µM in WT CYP119, N34E, N34E-D77R and D77R mutant, respectively. The reported Kd for Pdx binding for WT is 2100 µM. Difference spectra of Pdx binding to WT CYP119 and mutants were followed to obtain dissociation constants. The observed Kd values for WT CYP119 and N34E, D77R, N34E-D77R mutants were 2390 µM, 112 µM, 797 µM and 200 µM, respectively. These outcomes offer solid evidence that the N34E, N34E-D77R mutants bind to Pdx with higher affinity, thus, showing an increase in electron-transfer rate for 21-fold in N34E and 12-fold N34E-D77R mutation in CYP119-Pdx-PdR system
Chemical Composition Optimization and Isothermal Transformation of Δ-Transformation Plasticity Steel for the Third-Generation Advanced High-Strength Steel Grade
No full textA new low-manganese transformation-induced plasticity steel is designed with optimized nickel content to achieve superior strength and ductility while minimizing the use of expensive nickel. The steel is optimized using JMatPro software, then cast, and hot rolled. To assess the effect of intercritical annealing on austenite (martensite at room temperature) volume fraction and carbon content, hot-rolled steel samples quenched from different annealing temperatures (680-1100 degrees C) are used. Additionally, hot-rolled steel coupons are intercritically annealed at about 50% austenite formation temperature (740 degrees C) and then subjected to isothermal treatments at 300-425 degrees C for varying times (10-90 min). After optimizing these treatments to maximize retained austenite (RA), tensile specimens are heat-treated first at 740 degrees C and then isothermally at 325 degrees C. Thermodynamic calculations suggest that aluminum combined with silicon may lead to the delta ferrite formation, and even minimal nickel content can stabilize a considerable amount of austenite. In the experimental studies, it is shown that lower-temperature bainitic holding enhances austenite stability by enriching the carbon content. Optimized two-stage heat treatments yield up to 25.8% RA, with a tensile strength of 867.2 MPa and elongation of 40.6%, achieving a strength-elongation product of 35.2 GPax%, surpassing the third-generation advanced high-strength steel grades minimum requirement of 30 GPax%
Strengthening Historic Masonry Walls Using Sprayed Glass-Fibre Gypsum (gfrg) Against Settlement-Induced Damage
No full textIn this study, large-scale settlement tests were carried out on two test building samples consisting of masonry load-bearing walls, which are known to be sensitive to differential settlements. Test buildings were constructed in ½ scale to represent the characteristics of historical row buildings built in Istanbul in the 19th century. Test buildings consisted of two masonry walls connected to each other with reinforced concrete slabs, where additional loads were placed to explore the influence of different dead load arrangements. The walls of one of the buildings were strenghtened by spraying specially produced glass-fiber-reinforced gypsum material. The unreinforced and strengthened building models were tested under the same loads and were subjected to settlements at wall base level. The structural response of the walls (displacements and deformations) was monitored during the tests using both conventional devices (LVDTs) and optical cameras. While significant damage occurred for the unreinforced building, no damage was observed on the walls of the strengthened building. The results show that the use of glass-fiber-reinforced gypsum strengthening can provide effective protection against settlement-induced damage. It can be a good alternative strengthening material for masonry structures where the use of cement-based materials may be unsuitable. © Tongji University Press 2024
Engineering Periodontal Tissue Interfaces Using Multiphasic Scaffolds and Membranes for Guided Bone and Tissue Regeneration
No full textPeriodontal diseases are one of the greatest healthcare burdens worldwide. The periodontal tissue compartment is an anatomical tissue interface formed from the periodontal ligament, gingiva, cementum, and bone. This multifaceted composition makes tissue engineering strategies challenging to develop due to the interface of hard and soft tissues requiring multiphase scaffolds to recreate the native tissue architecture. Multilayer constructs can better mimic tissue interfaces due to the individually tuneable layers. They have different characteristics in each layer, with modulation of mechanical properties, material type, porosity, pore size, morphology, degradation properties, and drug-releasing profile all possible. The greatest challenge of multilayer constructs is to mechanically integrate consecutive layers to avoid delamination, especially when using multiple manufacturing processes. Here, we review the development of multilayer scaffolds that aim to recapitulate native periodontal tissue interfaces in terms of physical, chemical, and biological characteristics. Important properties of multiphasic biodegradable scaffolds are highlighted and summarised, with design requirements, biomaterials, and fabrication methods, as well as post-treatment and drug/growth factor incorporation discussed
GIS-AHP APPROACH FOR A COMPREHENSIVE FRAMEWORK TO DETERMINE THE SUITABLE REGIONS FOR GEOTHERMAL POWER PLANTS IN IZMIR, TÜRKİYE
No full textGeothermal energy is gaining more reputation and importance around the world. Correspondingly, suitable location selection is a critical step and has become necessary for the successful installation and operation of geothermal power plants. This study investigated suitability of İzmir region, located in the Aegean part of Türkiye, in terms of geothermal power plants applications by using the combination of Geographical Information System and Analytic Hierarchy Process. Based on the request of power plants, thirteen important criteria were evaluated under three main categories named as physical (C1), environmental (C2) and technical (C3). Moreover, expert’s opinions were taken into consideration to calculate the importance of these criteria. Key results showed that İzmir was suitable for geothermal power plants. The final suitability map layer pointed out that %8.73 (1.037 km2) of total area were determined as highly suitable regions in terms of installation. In addition, the obtained suitability map layer was compared with actual geothermal power plants. Based on the comparison study, power plants in Seferihisar were moderately suitable for geothermal power plants while the location of Balçova power plant was highly suitable. Regarding the suitability assessment in the present study, the location of Dikili power plants had the least suitability score