Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(11)
- Hasar, Ugur Cem(8)
- Kaya, Yunus(8)
- Özdemir, Akın(7)
- İspirli, Hümeyra(7)
- Şahin, Engin(7)
- Ertugrul, Mehmet(6)
- Yilmaz, Mustafa Tahsin(6)
- Abdioglu, Murat(4)
- Ozturk, Gokhan(4)
- Ozturk, Hamdullah(4)
- Uçurum, Metin(4)
- Abdioglu, M.(3)
- Cinar, Mehmet(3)
- Ozturk, K.(3)
- Ozturk, U. Kemal(3)
- Taylan, Osman(3)
- Asiri, Abdullah M.(2)
- Banaz, Emrullah(2)
- Bekir, Seyhan(2)
- Beydemir, Şükrü(2)
- Bulbuloglu, Semra(2)
- Can, Zehra(2)
- Can, Özgür Devrim(2)
- Chinna Babu, P.(2)
- Cinar, M.(2)
- Gökçe, H.S.(2)
- Izginli, Mucahit(2)
- Karabacak, M.(2)
- Karabacak, Mehmet(2)
- Korkmaz, Kader(2)
- Kurt, M.(2)
- Makas, Samet(2)
- Manci, Egemen(2)
- Okumus, Halil Ibrahim(2)
- Ozkat, Erkan Caner(2)
- Saricaoglu, Furkan Turker(2)
- Sağdıç, Osman(2)
- Sundaraganesan, N.(2)
- Söyüt, Hakan(2)
Yayınlar
- MakaleYalnız künye2023Scopus SJRQ1Parameter extraction method for reflection-asymmetric bianisotropic metamaterial slabs using one-port measurements
Hasar, Ugur Cem; Kaya, Yunus; Ozturk, Hamdullah; Ertugrul, Mehmet; Ramahi, Omar Mustafa
An effective microwave method is developed for extracting electromagnetic properties of bianisotropic metamaterial (MM) slabs. As a non-iterative method, it utilizes only the one-port (air-backed and metal-backed MM slab) scattering (S-) parameter measurements. This is a useful feature especially for vector network analyzers, such as MS46131A, MS46121B, and R60, performing only one-port S-parameter measurements. Electromagnetic properties of a bianisotropic MM slab formed by C-shaped resonators are measured by an X-band (8.2–12.4 GHz) rectangular waveguide setup. The effect of any gap between the short-circuit termination for metal-backed measurements and the end of the MM slab on extracted electromagnetic properties is also examined for evaluating the possible error for proposed method.
AtıfScopus3WoS3OpenAlex5
İncele - MakaleAçık Erişim2023Scopus SJRQ3Numerical investigation of the Mode I/Mode II fracture behavior of the hybrid composite joints with a hybrid bondline
Erbayrak, Engin
In this study, the fracture behavior of fracture characterization bonded joints consisting of hybrid composite adherends and hybrid bondlines under Mode I and Mode II loadings were investigated numerically. Numerical analysis was performed using LS-DYNA. Hybrid composite laminates (HCGFRE) obtained by sequencing plain woven glass fiber reinforced epoxy (GFRE) and plain woven carbon fiber reinforced laminates (CFRE) as adherends. Araldite AV138M and Araldite 2015 epoxy adhesives were also used to create the hybrid bondline. Mode I and mode II fracture behaviors were determined by numerical modeling of the Double Cantilever Beam (DCB) and End Notched Flexural (ENF) tests, respectively. In the numerical model, firstly, the fracture parameters of the relevant adhesives were found in the literature, and verification was made utilizing the numerical model. Then, the fracture behavior in both two modes was examined by forming a hybrid bondline. In the literature, there are restricted studies examining the fracture behavior of fracture characterization bonded joints with hybrid bondlines. Additionally, it is not encountered any study determining the both mode I and mode II fracture behavior of composite fracture characterization bonded joints with hybrid bondlines. Therefore, it is thought that this study will gain significant novelties to the existing literature.
AtıfScopus1OpenAlex2İncele - MakaleAçık Erişim2023Scopus SJRQ2Efficient bio-catalytic production of enentiopure (S)-(4-chlorophenyl)(phenyl)methanol as a drug precursor by using a novel rotatable composite design-based optimization strategy
Tozlu, Nesrullah; Bülbül, Ali Savaş; Özdemir, Akın; Şahin, Engin
Asymmetric bioreductions catalyzed by biocatalysts have demonstrated great promise in manufacturing chiral alcohols. On the other hand, the synthesis of (S)-(4-chlorophenyl)(phenyl)methanol ((S)-2), precursors of L-cloprastine and carbinoxamine, still presents considerable challenges due to the inadequate substrate quantity and production process. In this work, a novel rotatable composite design-based optimization technique was used with the Lactobacillus paracasei BD101 biocatalyst for the asymmetric reduction of (4-chlorophenyl)(phenyl)methanone (1). Optimization conditions of the reaction were determined by the proposed optimization strategy as: pH=5.85, temperature=37 °C, incubation time=71 h, and agitation speed=120 rpm. The reaction conversion and the product of enantiomeric excess (ee) were also predicted to be 97% and 99%, respectively. In the experimental study performed under the determined optimized conditions, (S)-2 was obtained with >99% ee, >99% conversion, and 97% yield. In addition, 1 with the amount of 15.166 g was completely converted to (S)-2 (14.85 g, 97% isolated yield) on a high-gram scale. Notice that the manufacture of (S)-2 on a gram scale utilizing a biocatalyst and an optimization technique is demonstrated in this work for the first time. Finally, an economical, effective, and environmentally friendly biocatalytic process for the biocatalytic synthesis of (S)-2, which have antitussive and antiemetic properties and relax the bronchial muscle, has been demonstrated by the novel rotatable composite design-based optimization method.
AtıfScopus3WoS3OpenAlex2İncele - MakaleAçık Erişim2023Scopus SJRQ1Structural characterization of potato starch modified by a 4,6-α-glucanotransferase B from Lactobacillus reuteri E81
Hassanein, Wael S.; İspirli, Hümeyra; Dertli, Enes; Yilmaz, Mustafa Tahsin
The recent reports have revealed that increase in amount of α-1,6 linkages by modification of potato starch with enzyme (glycosyltransferases) treatment gains slowly digestible properties to the starch; however, the formation of new α-1,6-glycosidic linkages diminish the thermal resistance of the starch granules. In this study, a putative GtfB-E81, (a 4,6-α-glucanotransferase-4,6-αGT) from L. reuteri E81 was firstly used to produce a short length of α-1,6 linkages. NMR results revealed that external short chains mostly comprised of 1–6 glucosyl units were newly produced in potato starch, and the α-1,6 linkage ratio was significantly increased from 2.9 % to 36.8 %, suggesting that this novel GtfB-E81 might have potentially an efficient transferase activity. In our study, native and GtfB-E81 modified starches showed fundamental similarities with respect to their molecular properties and treatment of native potato starch with GtfB-E81 did not remarkably change thermal stability of the potato starch, which seems to be very prominent for the food industry given the significantly decreased thermal stability results obtained for the enzyme modified starches reported in the literature. Therefore, the results of this study should open up emerging perspectives for regulating slowly digestible characteristics of potato starch in future studies without a significant change in the molecular, thermal, and crystallographic properties.
AtıfScopus14WoS14OpenAlex18
İncele - MakaleYalnız künye2023Scopus SJRQ1Utilisation of an active branching sucrase from Lactobacillus kunkeei AP-37 to produce techno-functional poly-oligosaccharides
İspirli, Hümeyra; Korkmaz, Kader; Arioglu-Tuncil, Seda; Bozkurt, Fatih; Sağdıç, Osman; Tunçil, Yunus Emre; Narbad, Arjan; Dertli, Enes
Glucansucrase AP-37 was extracted from the culture supernatant of Lactobacillus kunkeei AP-37 and characteristics of the glucan produced by the active glucansucrase in terms of structural and functional roles were determined in this study. A molecular weight around 300 kDa was observed for glucansucrase AP-37 and its acceptor reactions with maltose, melibiose and mannose were also conducted to unveil the prebiotic potential of the poly-oligosaccharides formed via these reactions. The core structure of glucan AP-37 was determined by 1H and 13C NMR and GC/MS analysis which revealed that glucan AP-37 was a highly branched dextran composing of high levels of (1 → 3)-linked α-D-glucose units with low levels of (1 → 2)-linked α-D-glucose units. The structural features of the glucan formed, demonstrated that glucansucrase AP-37 was an α-(1 → 3) branching sucrase. Dextran AP-37 was further characterised by FTIR analysis and XRD analysis demonstrated its amorphous nature. A fibrous compact morphology was observed for dextran AP-37 with SEM analysis whereas TGA and DSC analysis revealed its high stability as no degradation was observed up to 312 °C. Finally, the prebiotic potential of the dextran AP-37 and the gluco-oligosaccharides produced with the acceptor reaction of α-(1 → 3) branching sucrase AP-37 were determined and promising results were found for the gluco-oligosaccharides to act as prebiotics.
AtıfScopus13WoS12OpenAlex13İncele - MakaleAçık Erişim2023Scopus SJRQ1A bio-inspired solution to alleviate anisotropy of 3D printed engineered cementitious composites (3DP-ECC): Knitting/tilting filaments
Zhou, Wen; McGee, Wes; Gökçe, H. Süleyman; Li, Victor C.
Widely reported anisotropy in 3D printed cementitious structures has been a primary concern to structural integrity, especially for fiber-reinforced cementitious material, e.g., engineered cementitious composites (ECC). To alleviate the anisotropy present in 3D printed ECC (3DP-ECC), two innovative printing patterns, “knitting” and “tilting” filaments, were proposed, mimicking the natural crossed-lamellar structure of conch shells. 3D spatial paths were designed to allocate tensile/flexural resistance to multiple directions and to create an interwoven interface system to strengthen the structure. Four-point bending tests loading from three different directions were conducted. It was found that knitted and tilted filaments revealed superior or comparable bending performance to cast ECC in two favorable orientations. Furthermore, flexural performance in the weakest orientation was notably improved by knitting and tilting, with up-to-179% increases in flexural strength compared with that of parallel filaments. This novel approach holds great promise in alleviating anisotropy of 3DP-ECC without introducing additional reinforcement.
AtıfScopus45WoS39OpenAlex42İncele - Derleme MakaleAçık Erişim2022Scopus SJRQ1Impact of ultrasonication applications on color profile of foods
Kutlu, Naciye; Pandiselvam, R.; Kamiloglu, Aybike; Saka, Irem; Sruthi, N.U.; Kothakota, Anjineyulu; Socol, Claudia Terezia; Maerescu, Cristina Maria
Food color is a feature that provides preliminary information about their preference or consumption. There are dominant pigments that determine the color of each food; the most important pigments are anthocyanins (red–purple color), chlorophylls (green color), carotenoids (yellow-orange color), and betalains (red color). These pigments can be easily affected by temperature, light, oxygen, or pH, thereby altering their properties. Therefore, while processing, it is necessary to prevent the deterioration of these pigments to the maximum possible extent. Ultrasonication, which is one of the emerging non-thermal methods, has multidimensional applications in the food industry. The present review collates information on various aspects of ultrasonication technology, its mechanism of action, influencing factors, and the competence of different ultrasonication applications (drying, irradiation, extraction, pasteurization, cooking, tempering, etc.) in preserving the color of food. It was concluded that ultrasonication treatments provide low-temperature processing at a short time, which positively influences the color properties. However, selecting optimum ultrasonic processing conditions (frequency, power, time, etc.) is crucial for each food to obtain the best color. The key challenges and limitations of the technique and possible future applications are also covered in the paper, serving as a touchstone for further research in this area.
AtıfScopus135WoS118OpenAlex129İncele - MakaleAçık Erişim2022Scopus SJRQ2Efficient bioreduction of cyclohexyl phenyl ketone by Leuconostoc pseudomesenteroides N13 biocatalyst using a distance-based design-focused optimization model
Özdemir, Akın; Şahin, Engin
Whole-cell biocatalysts have been a popular method for the preparation of chiral alcohols. Although asymmetric reduction of cyclohexyl(phenyl)methanone (1) by chemical catalysts is common, a biocatalytic asymmetric reduction is extremely rare. In this respect, we report herein that Leuconostoc pseudomesenteroides N13 was successfully employed as a biocatalyst to reduce 1 to (S)-cyclohexyl(phenyl)methanol ((S)-2). Furthermore, the use of a mathematical optimization strategy for asymmetric reduction of substrate 1 is not known in the current literature. The new distance-based design-focused optimization model was used to enhance the conversion of the substrate, enantiomeric excess (ee) of product, and yield. The distance-based design-focused optimization model identified the following optimal bioreduction conditions: pH=6.46, temperature=30°C, incubation period=72 hours, and agitation speed=199 rpm. Then it was stated that under these ideal conditions, (S)-2 may be produced with 99 % ee and 98.46 % conversion rate (cr). (S)-2 was achieved with 99% ee, and 99% cr as a consequence of the experimental reaction carried out under the indicated optimization conditions. It has been shown that Leuconostoc pseudomesenteroides N13 can be utilized as a biocatalyst in asymmetric reduction reactions. This study, in addition to being the first example of a bioreduction of substrate 1 by mathematical optimization, also demonstrates for the first time the distance-based design-focused model can be used in the bioreduction reaction.
AtıfScopus9WoS9OpenAlex8İncele - MakaleAçık Erişim2022Scopus SJRQ3Investigation of adherence to immunosuppressive therapy and spiritual well-being in liver recipients
Gunes, Hüseyin; Bulbuloglu, Semra; Saritaş, Serdar
Objective: In our study, we investigated the relationship between spiritual well-being and adherence to immunosuppressive therapy after liver transplantation. Method: We conducted this descriptive and cross-sectional study with the participation of 131 liver transplant recipients after they had received their transplants. Data collection was carried out using a Personal Information Form, the Spiritual Well-Being Scale and the Immunosuppressant Therapy Adherence Scale. The IBM Statistical Package for the Social Sciences 25.0 was used for the statistical analyses. Results: While 73.3% of the patients were at the ages of 45–64, 72.5% were male, and 39.7% had been using immunosuppressive medication for a period between 6 months and 1 year. The rate of corticosteroid use among the patients was 30.5%, and the rate of antimetabolite use was 21.4%. A positive and significant relationship was found between adherence to immunosuppressive treatment and spiritual well-being (B = 0.425, p = 0.017). Conclusion: Spiritual well-being is an inexpensive, effective and easy strategy to increase adherence to immunosuppressive treatment. Awareness should be raised in physicians and nurses about the importance of spiritual well-being, and they should be encouraged to support spiritual well-being.
AtıfScopus5WoS6OpenAlex9İncele - MakaleYalnız künye2022Scopus SJRQ2Synthesis of 7-azaindole based carbohydrazides and 1,3,4-oxadiazoles; Antioxidant activity, α-glucosidase inhibition properties and docking study
Izgi, Samet; Sengul, Ibrahim F.; Şahin, Engin; Koca, Mehmet Serdar; Cebeci, Fatma; Kandemir, Hakan
In this current work, 7-azaindole based 1,3,4-oxadiazoles have been successfully prepared by treatment of 3-(hydrazonomethyl)-7-azaindole with the different acyl chlorides or acetic anhydrides to give the corresponding carbohydrazides, followed by iodine mediated synthetic protocol in order to afford the corresponding 2,5-disubstituted 1,3,4-oxadiazoles. The full characterization data of the novel compounds were obtained by utilizing 1H NMR, 13C NMR, FT-IR, high-resolution mass spectrometry and single crystal X-ray diffraction techniques. The antioxidant activity and α-glucosidase inhibition potential of the prepared compounds are examined by in vitro assays. The targeted hydrazide linked 7-azaindoles and their corresponding cyclized form 1,3,4-oxadiazoles exhibited inhibitory potential with IC50 values ranges between 0.46 and 24.92 mM. Plausible binding mode and interaction of ligands with α-glucosidase enzyme have been studied by molecular docking, supporting the experimental results.
AtıfScopus28WoS27İncele - MakaleAçık Erişim2022Scopus SJRQ2Anatomy, trichome micromorphology and phytochemical profile of Stachys rizeensis R.Bhattacharjee from Turkey
Gerçek, Yusuf Can; Acar Şahin, Aydan; Ecem Bayram, Nesrin; Çelik, Saffet; Sefalı, Abdurrahman; Gıdık, Betül; Cevahir Öz, Gül; Pınar, Nur Münevver
In recent years, the popularity of natural products and natural product formulations has increased due to their beneficial effects on health. As a part of this trend, Lamiaceae family members have attracted attention due to their rich bioactive properties. Although the Stachys rizeensis R.Bhattacharjee plant is an endemic plant species in Turkey, no studies focus on its characterization. Hence, the present study aims to demonstrate the anatomical, morphological and phytochemical characterization of S. rizeensis in Turkey. In the first stage of the study, anatomical and trichome morphological characterization was performed to contribute to the taxonomic definition of S. rizeensis was found to be anatomically different from some other previously studied Stachys sp. by showing lacunar collenchyma type, uncertain cambium at the corners, two or three rows of endodermis in certain areas in the stem and two rows of palisade parenchyma, capitate and peltate glandular trichomes in the leaf. In the second stage, the phenolic profile, total phenolic/flavonoid content and antioxidant activity of the plant extracts prepared using solvents with different polarities (ethanol, methanol, water, ethyl acetate and hexane) were tested to determine the phytochemical content of the plant. The phytochemical analysis supported by chemometric analysis (PCA and HCA) revealed that methanol was the most efficient organic solvent for the extraction of the phytochemical compounds of the plant. Additionally, it was observed that chlorogenic acid (1842.40–217,086.19 mg/kg), verbascoside (2591.43–204,429.81 mg/kg), luteolin (3579.56–88,636.14 mg/kg) and kaempferol (9706.30–50,340.93 mg/kg) compounds were present at maximum levels in this plant, in which 31 different phenolic compounds were scanned using LC-MS/MS. In addition, results obtained from the phytochemical analysis revealed that S. rizeensis is a valuable plant that can be used for medical protection/treatment and that it could also have a variety of culinary applications. The present study served as the first original report regarding the chemical profile and anatomical characteristics of S. rizeensis (Lamiaceae) from Turkey.
AtıfScopus4WoS4OpenAlex4İncele - MakaleAçık Erişim2022Scopus SJRQ4HRM method for identification of TP53 exon 5 and 8 mutations in human prostate cancer patients
Özmerdiven, Çağdaş Gökhun; Dirican, Ebubekir; Ayan, Semih; Tatar, Zeynep; Çakır, Sami; Güler, Yavuz; Karadağ, Abdullah; Soydaş, Tuğba; Uzunçakmak, Sevgi Karabulut; Aru, Melek
Background: The purpose of the present study was to perform a high-resolution melting (HRM) analysis to discover mutations in gene exons 5–8 of tumor protein p53 (TP53), as well as the relationships of these mutations to clinical parameters in prostate cancer (PC). Methods: Genomic DNA was extracted from 50 formalin-fixed paraffin-embedded (FFPE) tissues with PC. Mutations in exons 5 and 8 of TP53 were analyzed using the HRM method. Sanger sequencing was used to describe mutations. Results: According to the HRM analysis results, 21 (42%) PC samples had different normalized and shifted melting curves from other samples. Mutations in TP53 exons 5 and8 were observed in 12 (24%) patients by the Sanger method. The detection sensitivity of the HRM method in exon 5 and exon 8 mutations was 66.7% and 50%, respectively. PSA levels of PC patients with TP53 mutation were found to be lower than that of patients with no mutation (p = 0.8270). However, we did not find any correlations between TP53 mutations and clinical parameters (p > 0.05). Conclusions: HRM analysis is a simple, rapid, and efficient mutation-scanning method for known/unknown mutations in TP53 exons 5and8, as well as an attractive method for detection of mutations and their analysis in FFPE tissues. Additional studies with larger patient populations are warranted to confirm the correlation between the TP53 mutations and PC risk.
- MakaleYalnız künye2022Scopus SJRQ1Structural and bioactive characteristics of a dextran produced by Lactobacillus kunkeei AK1
Yilmaz, Mustafa Tahsin; İspirli, Hümeyra; Taylan, Osman; Bilgrami, Anwar L.; Dertli, Enes
In this study, structural and techno-functional characteristics of an exopolysaccharide (EPS) produced by Lactobacillus kunkeei AK1 were determined. High-performance liquid chromatography (HPLC) analysis demonstrated that EPS AK1 was composed of only glucose units. 1H and 13C Nuclear magnetic resonance (NMR) analysis revealed that EPS AK1 was a dextran type EPS containing 4.78% (1 → 4)-linked α-D-glucose branches. The molecular weight of EPS AK1 was determined to be 45 kDa by Gel Permeation Chromatography (GPC) analysis. A high level of thermal stability up to 280 °C was determined for dextran AK1 detected by Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). Dextran AK1 appeared as regular spheres with compact morphology and as irregular particles in the solution with no clear cross-linking between the chains of the polysaccharide observed by Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) analysis, respectively. X-ray diffraction analysis (XRD) analysis demonstrated that dextran AK1 had a crystalline structure. A relatively strong antioxidant activity was observed for dextran AK1 determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging and cupric reducing antioxidant capacity (CUPRAC) tests. Finally, only a digestion ratio of 3.1% was observed for dextran AK1 following the in vitro simulated gastric digestion test.
AtıfScopus43WoS39OpenAlex41İncele - MakaleAçık Erişim2022Scopus SJRQ2A novel internal curing method for 3D-printed geopolymer structures reinforced with a steel cable: Electro-heating
Gökçe, H.S.; Güngör, O.; Öksüzer, N.
Buildability and structural integrity are the inherent challenges of 3D printed geopolymer structures needed to be overcome. Reinforcing with steel cable ensuring a higher structural integrity of the printed structure can simultaneously improve the buildability due to the heating capability of this component. The controllable instant heating capability of steel cable was achieved by the use of a specific circuit system in the study. As a novel internal curing technique, electro-heating is recommended in the additive manufacturing of steel cable-reinforced geopolymer structures by the authors.
AtıfScopus4WoS3OpenAlex5İncele - MakaleAçık Erişim2021Scopus SJRQ1Prediction of water-adulteration within honey by air-line de-embedding waveguide measurements
Hasar, Hafize; Hasar, Ugur Cem; Kaya, Yunus; Ozturk, Hamdullah; Izginli, Mucahit; Ozbek, Ibrahim Yucel; Oztas, Taskin; Canbolat, Mustafa Yildirim; Ertugrul, Mehmet
An efficient de-embedding air-line microwave method has been proposed for accurate relative complex permittivity, εr=εr′−iεr′′, measurement of water-adulteration level within honey. It could be effectively applied to eliminate the errors arising from usage of imperfect calibration standards because it bypasses the requirement of these standards. Its accuracy is improved by utilizing the unitary and similarity properties of a passive two-port network, and then is compared with the accuracy of a calibration-dependent method present in the literature by using normalized root-mean-square-error (N-RMSE) values of εr′ and εr′′ of distilled water, in reference to the Debye value. From this comparison, it is observed that N-RMSE values calculated for εr′ (and εr′′) by using this calibration-dependent method and the (improved) proposed method are, respectively, around 0.1955 (0.1002) and 0.1962 (1.1067), indicating a good agreement between them. After validation the proposed de-embedding method using distilled water measurements, tested pure honey was adulterated with distilled water by different percentage values δ ranging from 1% to 10% in 1% increments. It is observed that the maximum distance between extracted εr′ (or εr′′) values of adulterated honey by the applied calibration-dependent method and the proposed method is less than 2%. Afterward, an empirical formula was devised to fit εr′ and εr′′ values from measured εr of water-adulterated honey with various δ levels. It is noted that extracted εr′ is much more better fitted than extracted εr′′, especially for δ≤4. Next, an optimization process is followed to evaluate the frequency for optimum prediction of adulteration levels using the empirical formula based on εr′ or εr′′. It is noticed that optimized δ values using the empirical formula based on εr′ (with an average prediction error of around 0.071 at 4.5 GHz) are superior to optimized δ values using the empirical formula based on εr′′ (with an average prediction error of around 0.085 at 4.2 GHz) for prediction of previously known δ values. Sensitivity and uncertainty analyses were performed to assess and improve the accuracy of the proposed method.
AtıfScopus24WoS23OpenAlex24İncele - MakaleAçık Erişim2021Scopus SJRQ2Gamma-ray irradiation effects on capacitance and conductance of graphene-based Schottky diode
Efil Kutluoğlu, Esra; Öz Orhan, Elif; Bayram, Özkan; Bilge Ocak, Sema
The purpose of this study is to determine the effects of gamma (γ)-ray irradiation on capacitance and conductance features of Al/Graphene/Al2O3/p-Si structure. Graphene has been grown on copper foil by the Chemical Vapor Deposition (CVD) method and transferred onto Al2O3/p-Si by the wet transfer method. After Al/Graphene/Al2O3/p-Si structure has been exposed to 30 kGy and 60 kGy γ-ray irradiation, capacitance, and conductance measurements have been accomplished at 300 K. Electrical parameters have been compared before and after γ-ray irradiation for 50 kHz and 500 kHz. These results have been confirmed that capacitance and conductance values have increased after γ-ray irradiation and, have decreased when the radiation dose was increased from 30 kGy to 60 kGy. It has been observed that series resistance has decreased after 30 kGy radiation dose and has increased with increasing radiation dose.
AtıfScopus13WoS12OpenAlex14İncele - MakaleAçık Erişim2021Scopus SJRQ1Effect of sample deformation in longitudinal axis on material parameter extraction by waveguides
Hasar, Ugur Cem; Kaya, Yunus; Ozturk, Gokhan; Ertugrul, Mehmet
An analysis was performed for examining the consequences of sample deformation in longitudinal axis in the sample-loaded non-resonant waveguide techniques. Vertical and horizontal deformations were first simulated to understand the change in field distributions and corresponding scattering parameters. Then, effects of sample length, dielectric constant, and loss factor for these deformations on extracted electromagnetic properties were analyzed using simulated results. Finally, S-parameter measurements were carried out to understand the effect of vertical deformation on permittivity results and to examine any improper sample preparation by hand-made and machine-made samples by applying a statistical model based on mean, standard deviation, coefficient of variation, and confidence interval. It was noted that extracted dielectric constants of each tested dielectric sample (polyethylene, polypropylene, polyvinyl-chloride) were within the confidence interval range of 90% while their retrieved loss factors were within the confidence interval range of 90%, 95%, or 98%.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYalnız künye2021Scopus SJRQ1Bioprospection of Metschnikowia sp. isolates as biocontrol agents against postharvest fungal decays on lemons with their potential modes of action
Oztekin, Sebahat; Karbancioglu-Guler, Funda
In this study, various fruit were employed as biocontrol yeast reservoirs, and eleven distinct yeast cultures of Metschnikowia sp. belonging to 6 different species were identified with sequence-based analysis of the D1/D2 domain of 26S rDNA. For initial screening, Metschnikowia isolates were tested on Fusarium oxysporum, Botrytis cinerea, Penicillium digitatum, Penicillium expansum, and Alternaria alternata. The highest antagonism was obtained on green and blue Penicillium (83.63–100 %). All tested yeasts showed chitinase activity, while some had protease, pectinase, cellulase, β-1−3 glucanase, and gelatinase activities. Since lemons have high pectin content, three pectinase-free cultures at tested conditions with high in vitro antagonism on Penicillium were selected and used on lemons. The activities of the in vitro antifungal studies were found to be compatible with those of the in vivo, and P. digitatum's incidence was found to be higher than that of P. expansum on lemons. All tested pectinase-free Metschnikowia sp. lead to a significant reduction in the disease incidences and lesions at varying levels. The combined effect of lytic enzyme secretion, iron depletion, and volatile organic compounds (VOCs) production determined the antifungal mechanism of action. M. aff. fructicola demonstrated the highest biocontrol efficacy against Penicillium on lemons with an increasing shelf-life. The use of tentatively pectinase-negative Metschnikowia sp. as an antifungal biocontrol agent on lemons was considered for the first time. The findings will shed light on the effective use of Metschnikowia sp. as a potential biofungicide against the growth of postharvest fungal pathogens.
AtıfScopus57WoS51OpenAlex58İncele - MakaleAçık Erişim2021Scopus SJRQ1Toolbox for tracking and analyzing crowded mixture of colloidal particles
Yücel, Harun; Velu, Sabareesh K.P.
We present a MATLAB-based multiple particle tracking (mPosTracker) algorithm to detect and track crowded colloidal particles that are two-dimensionally imaged using digital video microscopy. Our algorithm adopts three optional detection methods using threshold settings namely; centroid method (CM), radial symmetry method (RSM) and partial radial symmetry method (pRSM). In contrast to other reported algorithms, it allows classifying a maximum of three types of particles based on area or intensity. Furthermore, we include a toolbox to perform quantitative particle analysis like number density, trajectories with mean square displacement, and Voronoi cells with six-fold bond parameters to reveal the physics of examined dataset. To demonstrate the abilities of mPosTracker, we show the analysis outcomes on synthetically and experimentally acquired time-lapse microscopy datasets. mPosTracker is suitable for studying the dynamics of crowd behaviour, self-assembly, and manipulation of multi-component colloids under external fields.
AtıfScopus2WoS2OpenAlex2İncele - MakaleYalnız künye2021Scopus SJRQ1Assessment of different solution methods for receding contact problems in functionally graded layered mediums
Yaylacı, Murat; Eyüboğlu, Ayşegül; Adıyaman, Gökhan; Yaylacı, Ecren Uzun; Öner, Erdal; Birinci, Ahmet
This paper presents a comparative study of different methods, such as the analytical method, finite element method (FEM), and multilayer perceptron (MLP) for analyzing a frictionless receding contact problem. The problem consists of two layers resting on a Winkler foundation. The top layer is functionally graded (FG) along the depth and pressed using a rigid cylindrical stamp, whereas the bottom layer is homogeneous. We assumed that the contact between the two layers, and that between the FG layer and the rigid cylindrical stamp are frictionless; additionally, compressive normal tractions can be transmitted through the interface. First, the problem was solved analytically using the theory of elasticity and integral transform techniques. Second, the finite element solution of the problem was obtained using ANSYS software. Finally, the problem was extended based on the MLP, which an artificial neural network used for different problem parameters. The results of this study showed that the variations in the contact lengths at the interface between the rigid cylindrical stamp and the FG layer, those between the homogeneous layer and the FG layer, and the maximum contact pressures at these interfaces depended on various dimensionless quantities such as the stamp radius, stiffness parameter, shear modulus ratio, and elastic spring constant ratio. We observed that the results obtained with the three different methods, namely the analytical method, FEM, and MLP, are extremely compatible with each other, thus proving the accuracy of these results.
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