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Koleksiyondaki öğeler
- MakaleYalnız künye2022(m1, m2)-Geometric Arithmetically Convex Functions and Related Inequalities
Kadakal, Mahir
In this manuscript, we introduce and study the concept of (m1, m2)-geometric arithmetically (GA) convex functions and their some algebric properties. In addition, we obtain Hermite-Hadamard type inequalities for the newly introduced this type of functions whose derivatives in absolute value are the class of (m1, m2)-GA-convex functions by using both well-known power mean and Hölder’s integral inequalities.
AtıfScopus2
İncele - MakaleYalnız künye2022Scopus SJRQ2Optimized Machine Learning Algorithms for Investigating the Relationship Between Economic Development and Human Capital
Ozden, Erdemalp; Guleryuz, Didem
In Economic Development, human capital was previously seen as production factors but gradually evolved into endogenous growth theories. Most of the previous studies have examined the relationships between economic development and human capital via econometric models. Since this relationship is usually nonlinear and machine learning (ML) models can resolve it better, this study investigates the relationships by employing ML methods to provide a new perspective. For this purpose, the optimized ML methods, namely Bayesian Tuned Support Vector Machine and Bayesian Tuned Gaussian Process Regression (BT-GPR), were performed to develop the prediction model for economic development. The hyperparameters have been optimized with the Bayes method by using different kernel functions to increase SVM and GPR methods' predictive performance. The Multiple Linear Regression model has been employed to make a comparison as an econometric model. The performance of the models is evaluated using three statistical metrics, namely, the root mean square error (RMSE), mean absolute error (MAE), and coefficient of determination (R2). The BT-GPR with the exponential kernel model has superior prediction ability with the highest accuracy (R2: 0.9727, RMSE: 0.4022, MAE: 0.3728 in the testing phase). The study shows that the BT-GPR model increases the accuracy of R2 6.4%, RMSE 10.7%, and MAE 1% compared with other developed models.
AtıfScopus27WoS18OpenAlex30
İncele - MakaleYalnız künye2021Scopus SJRQ2Characterization of physicochemical and antioxidant properties of Bayburt honey from the North-east part of Turkey
Bayram, Nesrin Ecem; Kara, Hasan Hüseyin; Can, Aslı Muslu; Bozkurt, Fatih; Akman, Perihan Kübra; Vardar, Sevgi Umay; Çebi, Nur; Yılmaz, Mustafa Tahsin; Sağdıç, Osman; Dertli, Enes
The aim of this study was to determine the physicochemical properties, bioactive substance content, and microbiological quality of sixty different honey samples collected from twelve different regions of Bayburt, Turkey. The samples were analyzed for their sugar, moisture, total phenolic, total flavonoid contents, and water activity, conductivity, pH values and colour, antiradical activity, and DSC properties. As a result of physicochemical analyses, it was determined that the samples examined complied with the standard values defined in the Turkish Food Codex in terms of the parameters examined. The results of the study showed that the total phenolic content (219.43-768.82 mg GAE kg−1), total flavonoid content (31.29-118.7 mg CAE kg−1) and DPPH (12.98%-94.79%) parameters differ widely among the honey samples. A principal component analysis (PCA) was applied to correlate the characteristics of honey with honey samples collected from different regions. This is the first comprehensive and original report about the physicochemical properties of honey produced in Bayburt, a region close to the Anzer region where the most expensive honey, Anzer honey, is produced.
AtıfScopus19WoS17OpenAlex23İncele - MakaleAçık Erişim2021Scopus SJRQ2Detection of fructophilic lactic acid bacteria (FLAB) in bee bread and bee pollen samples and determination of their functional roles
Ispirli, Hümeyra; Dertli, Enes
In this study, bee bread and bee pollen samples were characterized in terms of presence of fructophilic lactic acid bacteria (FLAB). Following discrimination and identification of FLAB strains, their functional roles were determined. Genotypic characterization of FLAB strains revealed the presence of 27 distinct strains belonging to Lactobacillus kunkeei (21), Fructobacillus fructosus (3), Lactobacillus plantarum (2), and Leuconostoc mesenteroides (1) strains. In terms of functional roles, all FLAB strains demonstrated high levels of autoaggregation and hydrophobicity properties whereas L. kunkeei and F. fructosus strains did not tolerate bile salts and low pH conditions. A low level of antibiotic resistance was observed among FLAB strains and importantly FLAB strains demonstrated high levels of antibacterial and antifungal activities where strain specific properties played roles. The highest exopolysaccharide (EPS) production yields were obtained for L. kunkeei AP15, AP37 and L. mesenteroides AP-40 which produced 2.79, 2.01, and 5.37 g/L EPS, respectively. Practical applications: Bee bread and bee pollen are among beneficial bee products produced and consumed in all over the world. Production of bee bread relies on the fermentation process of bee pollen where a special LAB group FLAB plays roles. Despite the increment of the importance of these products for human consumption, there is a lack of knowledge for the microbial composition of these products. In this study, FLAB strains were isolated and identified from bee bread and bee pollen samples, and their technofunctional role was determined. The FLAB strains would be evaluated as starter cultures for production of bee products under industrial conditions.
AtıfScopus28WoS23OpenAlex29İncele - MakaleYalnız künye2020Scopus SJRQ1D-optimal experimental design for production models in nonstandard experiments
Özdemir, Akın
Robust design is an effective Quality by Design method to reduce product variation by selecting levels of design factors. For a number of situations, a nonstandard design region with linearly limited resources is needed to conduct an experiment. In the literature, little attention has been given to the development of robust design models for the nonstandard design region with a combination of linearly limited resources and a limited number of design points. In this paper, a selection scheme of D-optimal experimental design points is proposed to generate design points using the modified exchange algorithm for the nonstandard design region while specifying linearly limited resources and the limited number of design points. The modified exchange algorithm is able to generate global design points with less time complexity than the improved Fedorov algorithm. In addition, robust design models linking a D-optimal experimental design with quality considerations are proposed in order to obtain optimum settings of design factors for the product. Comparative studies are also presented. Finally, a real-life experimental study shows that the proposed models with the desirability function and the sequential quadratic programming technique achieve greater variance reduction than the traditional counterparts.
AtıfScopus16WoS15OpenAlex15İncele - MakaleAçık Erişim2020Scopus SJRQ3The Relationship between Self-Regulation and Proportional Reasoning: The Mediating Role of Reflective Thinking towards Problem Solving
Öztürk, Mesut
The present study examines the mediating impact of reflective thinking on problem-solving among seventh-grade students, focusing on the link between self-regulation and proportional reasoning. A relational research model was used to provide the quantitative research design. The prediction model proposed in this study was tested with 279 seventh-grade middle-school students. Data were collected using the 'Reflective thinking towards problem-solving scale', the 'Perceived self-regulation scale' and the 'Proportional reasoning skill test'. Correlation and mediation analyses were performed on the collected data. The results demonstrate that reflective thinking toward problem-solving is significantly related to self-regulation and proportional reasoning. The mediation analysis shows that seventh-grade students' reflective-thinking skills towards problem-solving partially mediate between their self-regulation levels and proportional-reasoning skills.
AtıfScopus2WoS1OpenAlex10TR Dizin3
İncele - MakaleAçık Erişim2020Scopus SJRQ2Structural and technological characterization of ropy exopolysaccharides produced by Lactobacillus plantarum strains isolated from Tarhana
Zehir Şentürk, Duygu; Dertli, Enes; Erten, Hüseyin; Şimşek, Ömer
Exopolysaccharide producing starter cultures enable manufacturing “clean labeled” foods with improved textural and nutritional properties. The structural and technological analyses were performed on the ropy exopolysaccharides of six Lactobacillus plantarum. The incubation temperature, time and pH affected the exopolysaccharide production and high exopolysaccharide was produced in the presence of sucrose and maltose. The viscosity of exopolysaccharide was high at acidic conditions except PFC311E that showed viscous at neutral pH. Lactobacillus plantarum strains produced between 120 and 400 mg/L exopolysaccharide in which the highest was observed at L. plantarum PFC311. Exoploysaccharides were degraded over 300 °C except PFC311E that degraded at 295.7 °C. The NMR analyses revealed that the exopolysaccharides were synthesized by α1-6, α1-3 and α1-4 bonds with glucose, galactose and fructose moieties. In conclusion, L. plantarum PFC311 produced ropy exopolysaccharide with different structural, rheological and thermal properties and reveals potential to be used in food industry.
AtıfScopus42WoS37OpenAlex36İncele - MakaleAçık Erişim2022Scopus SJRQ3Approximating Functions in the Power-Type Weighted Variable Exponent Sobolev Space by the Hardy Averaging Operator
Ayazoglu, Rabil; Ekincioglu, Ismail; Şener, S. Şule
We investigate the problem of approximating function f in the power-type weighted variable exponent Sobolev space (Formula presented), by the Hardy averaging operator (Formula presented). If α(.) x 0 the function f lies in the power-type weighted variable exponent Sobolev space (Formula presented) (0, 1), it is shown that (Formula presented), where C is a positive constant. Moreover, we consider the problem of boundedness of Hardy averaging operator A in power-type weighted variable exponent grand Lebesgue spaces (Formula presented) (0, 1). The sufficient α(.) criterion established on the power-type weight function α(.) and exponent p(.) for the Hardy averaging operator to be bounded in these spaces.
AtıfScopus3WoS4OpenAlex3İncele - MakaleAçık Erişim2021Scopus SJRQ2Characterization of properties of Vanadium, Boron and Strontium addition on HPDC of A360 alloy
Gursoy, Ozen; Colak, Murat; Tur, Kazim; Dispinar, Derya
The demand for lighter weight decreased thickness and higher strength has become the focal point in the automotive industry. In order to meet such requirements, the addition of several alloying elements has been started to be investigated. In this work, the additions of V, B, and Sr on feedability and tensile properties of A360 has been studied. A mold design that consisted of test bars has been produced. Initially, a simulation was carried out to optimize the runners, filling, and solidification parameters. Following the tests, it was found that V addition revealed the highest UTS but low elongation at fracture, while B addition exhibited visa verse. On the other hand, impact energy was higher with B additions.
AtıfScopus13WoS12OpenAlex14İncele - MakaleAçık Erişim2021The relationship between attitudes toward the teaching profession, occupational resilience belief, and extra-role behavior: A moderated mediation model
Kara, Kürşad; Ada, Kübra
This study aims to examine the direct and indirect relationships between pre-service teachers’ attitudes toward the teaching profession, their occupational resilience beliefs, and their tendency to engage in extra-role behaviors within the framework of structural equation modeling. A relational survey model was used to design this quantitative investigation. The sample comprises 430 pre-service teachers who enrolled at four different programs at a state university in Turkey. The study used the attitudes toward teaching profession scale, the occupational resilience beliefs scale for pre-service teachers, and the extra-role behaviors scale (teacher form) as data collection tools. The researchers created hypothesis models examining the mediating and moderated mediating role of the occupational resilience belief in the effect that attitudes toward the teaching profession have on extra-role behaviors and tested these models within the framework of structural equation modeling. As a result of the study, it was found that the relationship strength between the attitudes toward the teaching profession, the occupational resilience belief, and extra-role behaviors was moderate. The study determined that occupational resilience belief plays a mediating role in the effect of pre-service teachers’ attitudes toward the teaching profession on extra-role behaviors. According to the results of the moderated mediation analysis, the influence of this indirect effect on extra-role behaviors varies according to the type of program studied, even though it does not differ significantly according to the class level of the pre-service teachers. This indirect effect is provided at the best level for pre-service teachers in the mathematics education program. However, the study concluded that the indirect effect influence significantly weakened in the Turkish education program.
AtıfScopus2OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ4Isolation of Distinct Lactobacillaceae spp. with Functional Characteristics from Traditional Sourdough Samples; [Geleneksel Ekşi Hamur Örneklerinden Fonksiyonel Özelliklere Sahip Farklı Lactobacillaceae spp. İzolasyonu]
İspirli, Hümeyra; Dertli, Enes
Lactic Acid Bacteria (LAB) were isolated from traditional sourdough samples, and functional properties of selected LAB species were determined. Five distinct strains Limosilactobacillus fermentum LR1, Lacticaseibacillus rhamnosus LR2, Levilactobacillus senmaizukei CE37, Lactiplantibacillus plantarum CE48 and Limosilactobacillus reuteri KD44A were identified following the genotypic discrimination of hundred isolates. Presence of bacteriocin genes in identified species was determined by PCR, and sourdough isolates have been shown to carry bacteriocin genes although they vary according to species. Exopolysaccharide (EPS) production tests showed that the amount of EPS production varies in different media and different incubation conditions. Antimicrobial effects of 5 different LAB species were determined against Bacillus cereus BC 6830, which cause rop problems, and other pathogen species and also molds isolated from bread. Amylolytic activities of isolates, which are important in terms of technological roles, were determined genotypically and phenotypically. Finally, the phytase and phosphatase activities of these species were studied. This study was aimed to unveil the functional sourdough LAB species to be used for industrial purposes.
AtıfScopus4OpenAlex3İncele - MakaleYalnız künye2022Scopus SJRQ1Investigation of antibacterial, antifungal, antibiofilm, antioxidant and anticancer properties of methanol extracts of Salvia marashica İlçim, Celep & Doğan and Salvia caespitosa Montbret & Aucher ex Benth plants with medicinal importance
Bostanci, Maside Temiz; Bulbul, Ali Savas; Celik, Ibrahim Seyfettin; Kocabas, Yusuf Ziya; Burhan, Hakan; Bayat, Ramazan; Sen, Fatih; Zakariae, Nilofar; Esmaeili, Roghayeh; Jafari, Hedayat
In this study, Antimicrobial, Antifungal and Antibiofilm activity tests on 16 bacteria and 2 fungi of Salvia marashica İlçim, Celep & Doğan and Salvia caespitosa Montbret & Aucher ex Benth species were performed by Agar Well Diffusion and Microdilution methods. Salvia species showed sensitivity with a zone diameter of 12–16 mm. Concentrations of 0.5 mg/ml to 16 mg/ml by the dilution method were used to determine the Minimum inhibited concentration (MIC) and Minimum bactericidal concentration (MBK). The MIC values of the plants are mostly 0.5 mg/ml - 4 mg/ml and MBC values are between 0.5 mg/ml - 8 mg/ml. Antifungal activity findings are remarkable on the species and it has been observed to have very high effects especially on Candida parapsilosis. When the antioxidant research findings are examined; It was observed that Salvia marashica and Salvia caespitosa plants have approximately 75% antioxidant activity at 1 mg/ml, and findings mostly directly proportional between concentrations and antioxidant activity capacity were recorded. MCF-7 and HUVEC cell lines were used to investigate anticancer activity properties. In line with the findings, while the IC50 value of Salvia marashica on the MCF-7 Cell line was 0.125 mg/ml, it was 1.65 mg/ml in the HUVEC cell line, while the IC50 value of Salvia caespitosa on the MCF-7 Cell line was 0.115 mg/ml in the HUVEC Cell line. It was found to be 9.87 mg/ml. It has been proven that both Salvia species have a cytotoxic effect on the MCF-7 Cell line.
AtıfScopus21WoS16OpenAlex23
İncele - MakaleYalnız künye2021Scopus SJRQ2Asymmetric reduction of aromatic heterocyclic ketones with bio-based catalyst Lactobacillus kefiri P2
Baydaş, Yasemin; Kalay, Erbay; Şahin, Engin
Abstract: Chiral heterocyclic secondary alcohols have received much attention due to their widespread use in pharmaceutical intermediates. In this study, Lactobacillus kefiri P2 biocatalysts isolated from traditional dairy products, were used to catalyze the asymmetric reduction of prochiral ketones to chiral secondary alcohols. Secondary chiral carbinols were obtained by asymmetric bioreduction of different prochiral substrates with results up to > 99% enantiomeric excess (ee). (R)-1-(benzofuran-2-yl)ethanol 5a, which can be used in the synthesis of pharmaceuticals such as bufuralols potent nonselective β-blockers antagonists, Amiodarone (cardiac anti-arrhythmic), and Benziodarone (coronary vasodilator), was produced in gram-scale, high yield and enantiomerically pure form using L. kefiri P2 biocatalysts. The gram-scale production was carried out, and 9.70 g of (R)-5a in enantiomerically pure form was obtained in 96% yield. Also, production of (R)-5a in terms of yield and gram scale through catalytic asymmetric reduction using the biocatalyst was the highest report so far. This is a cost-effective, clean and eco-friendly process for the preparation of chiral secondary alcohols compared to chemical processes. From an environmental and economic perspective, this biocatalytic method has great application potential, making it a green and sustainable way of synthesis. Graphical Abstract: [Figure not available: see fulltext.]
AtıfScopus8WoS8OpenAlex9İncele - Kitap BölümüYalnız künye2021Socioeconomic Analyses on Covid-19, Underdevelopment, and Inequalities
Gültekın, Ömer Faruk
- MakaleAçık Erişim2021Scopus SJRQ1Effects of ozone treatment to milk and whey concentrates on degradation of antibiotics and aflatoxin and physicochemical and microbiological characteristics
Sert, Durmuş; Mercan, Emin
The aim of this study was to investigate the effects of the ozone treatment (OT) to milk concentrate (MC) and whey concentrate (WC) on the physicochemical and textural properties, as well as, on the microbial, antibiotic, and aflatoxin content. For that purpose, OT was applied to MC and WC samples 0 (control), 5, 10, 15, 30, or 60 min. OT (60 min) achieved 18.9 and 9.9% degradation of aflatoxin M1 in MC and WC, respectively. OT caused degradation of β–lactam, and tetracycline in concentrates. Volume mean diameter of MC was increased by OT, those of WC was decreased. The firmness and consistency values of ozone-treated concentrates were lower than the control groups. OT decreased the cohesivity of MC. OT increased the lightness of samples, while it decreased yellowness. In MC and WC samples, OT was effective in reducing the microbial load. The degradation of antibiotics and aflatoxin, and reducing the microbial load of concentrates by OT are crucial for human health and the processing of dairy products.
AtıfScopus32WoS26OpenAlex36İncele - MakaleAçık Erişim2021Scopus SJRQ3An Action Research on Improving Classroom Communication and Interaction in Social Studies Teaching
Aksoy, Mutlu; Ceylan, Tuncay
The aim of this research is to reveal how communication and interaction in classrooms can be enhanced with the communicative approach education provided for social studies teachers. The participants of this research were five social studies teachers working at secondary schools and their 7th grade students, N = 110. The data collection tools adopted in this research were video and audio recordings, documents, semistructured interview forms, and stimulated recall interview forms. The data obtained from recordings of lessons were analyzed using the communicative approach, and the data obtained from document review and interview were analyzed using the content analysis method. The results of the study show that social studies curriculum contains items that require both dialogical and authoritative discourses and that the course books are prepared accordingly, but teachers as the practitioners of the program do not conduct their lessons accordingly. Instead, all the teachers participating in the research used only authoritative (interactive/noninteractive) approaches and they did not include dialogical (interactive/noninteractive) approaches at all. This situation, which is seen as a problem in terms of conducting successful in-class communication and interaction, has been solved in three action cycles with one of the teachers. The teacher who used only authoritative (interactive/noninteractive) approaches in her lessons prior to the trainings started to include dialogical (interactive/noninteractive) approaches too. It was also observed that the teacher's impression of the lessons carried out by adopting the communicative approach model was positive. As a result of the research, it was concluded that the communicative approach model is applicable in the social studies course. It can be said that the trainings given to the teachers created awareness about the use of the communicative approach model in classroom communication and interaction and provided benefits in diversifying discourse styles.
AtıfScopus7WoS3OpenAlex13İncele - MakaleAçık Erişim2021On Involute-Evolute Curve Pair in Semi-Euclidean Space
Aydın, Tuba Ağırman; Kocayigit, Hüseyin
In this study, a kind of generalized involute and evolute curve pair is considered in 4 dimensional semi Euclidean space with 2 index. The curvatures and the associated Frenet Frame of this kind of generalized involute-evolute curve pair are presented.
AtıfOpenAlex1İncele - MakaleYalnız künye2022Scopus SJRQ2Brand portfolio strategies effects on consumers' attitude
Yilmazel, Sefa Emre; Özer, Leyla
Purpose: The aim of this study is to determine the effects of brand components (CBBE, brand fit, brand image, brand reputation, brand familiarity) on consumers brand portfolio attitude via perceived risk (for two main portfolio strategies). Design/methodology/approach: The study used a structured questionnaire to collect primary data from 636 consumers who made purchases from companies using house of brand (318) and branded house strategy (318). By conducting reliability and validity analysis, the model of this study was tested with confirmatory factor analysis and path analysis methods, using structural equation modeling. Findings: According to the results of the path analysis, the effects of CBBE and brand reputation on brand attitude were confirmed for both house of brand and branded house strategy. Moreover, the full and partial mediating effect of perceived risk was proven in the relationships. Research limitations/implications: One of the limitations of the study is determining a portfolio of brands for each strategy and collecting data for these brands. In addition, since the number of consumers using brand portfolios could not be reached in the study, data could be collected using the purposeful convenience sampling method. For this reason, it is thought that research conducted with the data obtained through systematic sampling methods can yield more reliable results. Practical implications: Managers of companies with a brand portfolio should work on a main strategy that enhances CBBE and brand reputation regardless of the strategy they use. After these two variables, the variable that portfolio managers need to address is brand fit. Originality/value: It will offer different perspectives in terms of understanding which portfolio strategy is needed, and which predecessors and outputs can be produced. Also, the findings of the research will produce important results to reduce the perceived risks of consumers and increase their positive attitudes toward brand portfolios.
AtıfScopus7WoS6OpenAlex8İncele - MakaleYayıncıda açık erişim2022Scopus SJRQ1Analysis of mitochondrial DNA cytochrome-b (CYB) and ATPase-6 gene mutations in COVID-19 patients
Dirican, Ebubekir; Savrun, Şeyda Tuba; Aydın, İsmail Erkan; Gülbay, Gonca; Karaman, Ülkü
Coronavirus disease of 2019 (COVID-19) is a pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Mutations of mitochondrial DNA (mtDNA) are becoming increasingly common in various diseases. This study aims to investigate mutations in the cytochrome-b (CYB) and adenosine triphosphatase-6 (ATPase-6) genes of mtDNA in COVID-19 patients. The association between mtDNA mutations and clinical outcomes is investigated here. In the present study, mutations of the mtDNA genes CYB and ATPase-6 were investigated in COVID-19 (+) (n = 65) and COVID-19 (−) patients (n = 65). First, we isolated DNA from the blood samples. After the PCR analyses, the mutations were defined using Sanger DNA sequencing. The age, creatinine, ferritin, and CRP levels of the COVID 19 (+) patients were higher than those of the COVID-19 (−) patients (p = 0.0036, p = 0.0383, p = 0.0305, p < 0.0001, respectively). We also found 16 different mutations in the CYB gene and 14 different mutations in the ATPase-6 gene. The incidences of CYB gene mutations A15326G, T15454C, and C15452A were higher in COVID-19 (+) patients than COVID-19 (−) patients; p < 0.0001: OR (95% CI): 4.966 (2.215−10.89), p = 0.0226, and p = 0.0226, respectively. In contrast, the incidences of A8860G and G9055A ATPase-6 gene mutations were higher in COVID-19 (+) patients than COVID-19 (−) patients; p < 0.0001: OR (95%CI): 5.333 (2.359−12.16) and p = 0.0121 respectively. Yet, no significant relationship was found between mtDNA mutations and patients' age and biochemical parameters (p > 0.05). The results showed that the frequency of mtDNA mutations in COVID-19 patients is quite high and it is important to investigate the association of these mutations with other genetic mechanisms in larger patient populations.
AtıfScopus14WoS16OpenAlex21İncele - MakaleAçık Erişim2020Scopus SJRQ3Preservice teachers' metaphors about the concept of space perception
Kuzey, Mehmet
The aim of this study is to reveal the metaphors produced by the students of the Faculty of education regarding the concept of space perception. In accordance with this aim, the phenomenon design from qualitative research designs was used. The working group consists of 261 teachers who study in the Departments of Bayburt University Faculty of Education, Turkish, Social Sciences and primary education in the 2018-2019 academic year. "Perception of spatial" in order to determine the metaphors produced by the teacher candidates for the concept of "perception of spatial"... like/is similar to because... "the semi-structured form containing the statement was distributed and they were asked to convey their thoughts. The data obtained at the end of the study were analyzed in accordance with the content analysis. Participants produced a total of 109 valid metaphors for the concept of space perception, and these metaphors were grouped under 10 different categories. As a result of the study, it was determined that half of the teachers associated the concept of space perception directly with the words that contain the meaning of the concept of space.
AtıfScopus2OpenAlex5İncele
