Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(116)
- Şahin, Engin(48)
- Kaya, Yunus(46)
- Özen, Soner(46)
- İspirli, Hümeyra(45)
- Pat, Suat(44)
- Şenay, Volkan(42)
- Korkmaz, Şadan(36)
- Yilmaz, Mustafa Tahsin(33)
- Kutlu, Naciye(32)
- Cuce, Erdem(31)
- Öner, Erdal(31)
- Artar, Musa(30)
- Ertugrul, Mehmet(29)
- Hasar, Ugur Cem(29)
- Mercan, Emin(28)
- Bayraktar, Bülent(27)
- Bayram, Sinan(27)
- Can, Zehra(25)
- Ecem Bayram, Nesrin(25)
- Çolak, Murat(23)
- Özdemir, Akın(23)
- Cuce, Pinar Mert(22)
- Sert, Durmuş(22)
- Ayata, Ümit(21)
- Bayram, Ozkan(21)
- Dirican, Ebubekir(20)
- Abdioglu, Murat(19)
- Ayazoglu, Rabil(19)
- Birinci, Ahmet(19)
- Kamiloğlu, Aybike(19)
- Gerçek, Yusuf Can(18)
- Taylan, Osman(18)
- Tozlu, Alperen(18)
- Gul, Volkan(15)
- Hasar, Ugur C.(15)
- Kadakal, Mahir(15)
- Sagdic, Osman(15)
- Ergün, Mustafa(14)
- Kadakal, Huriye(14)
Yayınlar
- MakaleAçık Erişim2024Scopus SJRQ4SILVER AND ZINC NANOPARTICLES BIOSYNTHESIS USING LAUREL EXTRACT AND INVESTIGATION OF THE PHOTOCATALYTIC PROPERTIES
Taş, Recep; Köroğlu, Ebru; Karakuş, Ahmet; Bülbül, Ali Savaş; Taş, Nilay Akkuş
Metal nanoparticles that are widely studied in optoelectronics, catalysis, medicine, and sensors offer remarkable optical and electronic properties. To address the cost and environmental concerns associated with their synthesis, this study employs an environmentally friendly method using Laureus nobilis extract to produce silver and zinc nanoparticles, which are prominent in nanotechnology. This study includes investigations of factors such as reaction time, AgNO3/laurel ratio, Zn(Ac)2 H2O/laurel ratio and temperature in nanoparticle biosynthesis to optimize the process. The next stage was set to evaluate the photocatalytic performance of these nanoparticles, specifically against the methylene blue dye under dark and UV light conditions. Parameters such as pollutant decomposition, degradation rate, catalyst stability, and nanoparticle recovery were analysed. Structural characterization of the obtained nanoparticles was performed using UV-Vis, FTIR, SEM, and XRD techniques. The photocatalytic results showed significant degradation percentages for LB-AgNP (silver nanoparticles synthesized with Laureus nobilis extract) (97.5%) and LB-ZnNP (zinc nanoparticles synthesized with Laureus nobilis extract) (90.9%). LB-ZnNP showed superior performance. Therefore, LB-AgNP and LB-ZnNP are promising photocatalysts for water purification and the elimination of toxic organic pollutants.
AtıfScopus1WoS1OpenAlex1
İncele - MakaleAçık Erişim2024Scopus SJRQ1Salivary apelin hormone response and dysfunctional attitudes in adolescents in Türkiye: a relational screening model
Kirbaş, Zila Özlem; Bayraktar, Bülent; Aktaş, Elif Odabaşi
Background: Adolescence is the period in which physical and emotional changes occur through hormones, the individual acquires gender characteristics and prepares for the adult role psychologically and physically. Dysfunctional attitudes are beliefs and attitudes that can lead to depression by causing negative thoughts about oneself, others, and the future.Dysfunctional attitudes negatively affect children’s mental health. Hormones have a significant impact on human behavior and cognitive functions. However, little is known about the role and influence of hormones on dysfunctional attitudes. Apelin is a hormone responsible for controlling emotions by regulating emotional behavior. The level of dysfunctional attitudes is one of the important issues in nursing practice in terms of protecting and improving children’s mental health. However, little is known about the role and impact of hormones on dysfunctional attitudes.This study aimed to examine adolescents’ dysfunctional attitudes and salivary apelin hormone levels in terms of sociodemographic variables. Methods: The study was conducted in a relational screening model with 151 adolescents aged 9–14 years who were reported to be clinically healthy in Türkiye. Apelin hormone levels were analyzed by ELISA technique in the saliva samples of the participants. In the evaluation of dysfunctional attitudes, the relationship between the score obtained from the dysfunctional attitude scale and salivary hormone levels was evaluated. Results: In the study, a negative, strong and statistically significant correlation was found between the average salivary apelin hormone level and dysfunctional attitudes of adolescents (p =.000). Mean salivary hormone levels of apelin in adolescent girls and boys were 0.696 (SD 0.052) ng/ml, respectively; while 0.671 (SD 0.047) ng/ml was determined (p =.002), dysfunctional attitudes scale scores were 52.95 (SD 14.43); it was determined as 59.04 (SD 14.22) (p =.006). On the other hand, the highest average salivary apelin hormone level (p =.038). and the lowest level of dysfunctional attitudes were determined in adolescent girls aged 13–14 years (p =.028). Conclusions: In our study, we found that while the salivary apelin hormone levels of adolescents decreased, their dysfunctional attitudes increased. We found that adolescents’ dysfunctional attitudes decreased with age. In contrast, apelin hormone levels increased with age.
AtıfScopus9WoS10
İncele - MakaleAçık Erişim2024Scopus SJRQ1Ultrasound-assisted deep eutectic solvent extraction of bioactive compounds from persimmon calyx
Kutlu, Naciye; Kamiloğlu, Aybike; Abca, Tuğba Elbir; Yilmaz, Özlem
Abstract: This study aimed to investigate the ultrasound-assisted extraction of bioactive compounds from persimmon (Diospyros kaki) calyx by deep eutectic solvents (DES) with different molar ratios. For this reason, the prepared DES extracts’ total phenolic–flavonoid compounds and antioxidant activities (1,1-diphenyl-2-picrilhydrazyl radical scavenging activity [DPPH•], Cupric Reducing Antioxidant Capacity (CUPRAC), and ferric reducing antioxidant power [FRAP]) were investigated as a result of the experimental design and optimization study conducted for this purpose. A sonication time of 20 min was determined as the optimal condition. Under these conditions, a molar ratio of 1.9:1 (lactic acid:choline chloride) and a water ratio of 70% provided the highest phenolic/flavonoid compounds and antioxidative activity. Correlations among water ratio, molar ratio, and sonication time were determined using principal component analysis (PCA). In conditions where total flavonoid compound, FRAP, and DPPH• are high due to PCA, it can be concluded that the sonication time is at high level; on the contrary, the water and molar ratios are at low level. In conclusion, ultrasound-assisted extraction using DES proved effective in persimmon calyx. Therefore, it can be recommended to use these environmentally friendly green solvents as an alternative to organic solvents in preparing extracts in various fields. Practical Application: This study shows the effectiveness of the ultrasound-assisted green extraction method using persimmon calyx specified as waste. These findings are compelling in the food industry in terms of consumers being now aware of green technology and the discovery that calyx is a good source of bioactive compounds.
AtıfScopus19WoS21OpenAlex23İncele - MakaleAçık Erişim2024Scopus SJRQ2Optical, structural, morphological, and gas sensing properties of Mg-doped α-Fe2O3 thin films deposited by RF and DC magnetron Co-sputtering technique
Sarıtaş, Sevda; Merhan Muğlu, Günay; Turgut, Erdal; Kundakçı, Mutlu; Yıldırım, Muhammet; Şenay, Volkan
In this research, Mg-doped hematite (α-Fe2O3) thin films with different Mg-doping concentrations were synthesized on glass substrates using the direct current (DC) and radio frequency (RF) magnetron co-sputtering technique, and the changes of some physical properties due to the concentration of the dopant were investigated. The optical, structural, morphological, and elemental properties of the obtained Mg-doped α-Fe2O3 thin films were determined by X-ray diffraction (XRD) analysis, UV–Vis spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), dispersive X-ray spectroscopy and atomic force microscopy (AFM). XRD analysis revealed that the investigated thin films have a rhombohedral crystal structure. The deposition of films at different DC sputtering voltages caused significant variations in stoichiometry and nanostructure. The thin films' band gap energy values were estimated based on absorption measurements, and results ranged from 2.15 eV to 2.69 eV. Raman peaks were observed between 218 cm−1 and 1305 cm−1. The thin films exhibit uniform surface morphology throughout the substrate according to the SEM images. The low RMS roughness values obtained from AFM images showed that the surfaces of Mg:Fe2O3 thin films are smooth. The Mg-doped α-Fe2O3 thin film doped by 150 W DC voltage exhibited a good gas-sensing response at 300 °C. A remarkably quick response/recovery time was achieved.
AtıfScopus19WoS13OpenAlex20İncele - MakaleAçık Erişim2024Scopus SJRQ1District heating based on exhaust gas produced from end-of-life tires in Erzincan: Thermoeconomic analysis and optimization
Güngör, Osman; Tozlu, Alperen; Arslantürk, Cihat; Özahi, Emrah
This paper presents the thermoeconomic analysis and optimization of the Erzincan Waste Tire Recycling and Power Plant (EWTRPP) in Turkey and its waste heat-based district heating (DH) system. A thermoeconomical method, namely the specific exergy costing (SPECO), is applied to allocate cost flows through subcomponents of an actual existing plant. Besides, the obtained thermoeconomic results are improved by using an optimization method, namely non-dominant sorting genetic algorithm (NSGA-II), considering the temperature of the exhaust gas discharged to the atmosphere (T25), the thermal conductivity value of the insulation material (ki) and pipe roughness value (s). The energy and exergy efficiencies of the existing plant are found to be 27.37% and 35.57%, respectively, considering the data of the actual plant. Moreover, the energy and exergy efficiencies of the waste heat-based DH system are found to be 43.08% and 55.99%, respectively. The total cost rate of the overall system is deduced 13.98 $/hby means of SPECO method. According to the results of the NSGA-II optimization method, the exergy efficiency and total cost rate of the overall system are evaluated as 6.93% and −2.51 $/h, respectively. Furthermore, it is also proposed that 1304 dwellings can be heated owing to the DH system utilizing the existing exhaust gas.
AtıfScopus9WoS8OpenAlex7İncele - MakaleYalnız künye2024Scopus SJRQ2Effect of different carbon sources on exopolysaccharide production of Lactiplantibacillus pentosus KS27 and optimization of production conditions using Box-Behnken designing
Bekar, Fevzi; Kamiloglu, Aybike
This study aimed to determine the exopolysaccharide (EPS) production of Lactiplantibacillus pentosus KS27 depending on temperature, incubation time, and medium composition and to determine the optimum conditions. Characterization was carried out for the exopolysaccharide produced under optimum conditions. In the study, three different conditions (25 °C, 35 °C, 45 °C) were used for temperature, glycerol, and sucrose as media, and three different periods (24 h, 36 h, and 48 h) were used. It was determined that the solubility of EPS produced under optimal conditions had the highest water content (98 ± 0.01%), while the water binding capacity was also found to be as high as 1970 ± 0.01% and complied with common EPS characteristics. Differential scanning calorimeter analysis showed a gradual deterioration up to 191.88 °C and a slow decline up to 400 °C. FTIR analysis deciphered peak values between 3289 and 517 cm−1, and functional groups were detected. When the nuclear magnetic resonance (NMR) spectrum was examined, a heterogeneous structure appropriate to the structure of EPS was found by defining the peak entities in three separate regions.
AtıfScopus5WoS5OpenAlex6İncele - MakaleAçık Erişim2024Scopus SJRQ1The impact of inactivity during the COVID-19 pandemic on the physical performance of high school athletes
Asan, Selim; Ulupınar, Süleyman; Özbay, Serhat; Namlı, Sevinç; Gençoğlu, Cebrail; Canyurt, Ferhat; Çingöz, Yunus Emre; Özkara, Abdullah Bora
Background/Objective: This study was conducted during the 2019–2020 academic year to evaluate the impact of participation in school sports on students’ Body Mass Index (BMI) and Assessing Levels of Physical Activity (ALPHA) test scores. Interrupted by the COVID-19 pandemic, which led to a suspension of in-person education, the study resumed in September 2021, refocusing on the effects of pandemic-induced inactivity on the physical fitness levels of the same cohort. Methods: The study included twenty-nine male high school students (age: 17,24 ± 0,73 years), divided into thirteen athletes (participating in sports such as football, basketball, and track) and sixteen non-athletic counterparts. They underwent reassessment using the ALPHA test battery, evaluating cardiorespiratory, musculoskeletal, and motor skills fitness. Data were analyzed using independent and paired samples t-tests and a two-way repeated measures ANOVA to assess changes over time and between groups. Discriminant function analysis evaluated the ALPHA test’s ability to classify students based on their athletic status pre- and post-pandemic. Results: Initially, athlete students exhibited significantly better BMI, 20 m shuttle run, and 4 × 10 m speed run scores compared to their non-athlete peers. After the pandemic, only the 20 m shuttle run scores remained significantly higher for athletes, with diminished distinctions in other fitness areas. The classification accuracy of the ALPHA test battery decreased from 89.7 to 75.9% post-pandemic. Conclusion: The enforced sedentary lifestyle due to the COVID-19 pandemic adversely affected all students, particularly diminishing health-related fitness parameters such as body composition, cardiorespiratory and musculoskeletal strength, and motor skills. Students previously engaged in regular physical activity, notably school athletes, experienced significant fitness declines. This highlights the urgent need for targeted interventions to encourage active lifestyles among youth in the post-pandemic phase, aiming to avert long-term adverse health outcomes.
AtıfScopus8WoS5OpenAlex8İncele - MakaleAçık Erişim2024Scopus SJRQ3Multifunctional electroless nickel boron composite coatings incorporated by magnesium diboride ceramic particles
Bülbül, Ferhat; Kara, Adem
In this study, the role of MgB2 in composite coatings is pivotal. Electroless Ni–B plating, a current-free chemical reduction process, deposits nickel–boron coatings. Other than MgB2, reinforcements like SiC, B4C, and so forth are used with Ni–B coatings for improved properties. The research focuses on Ni–B/MgB2 coatings on AISI 4140 steel using electroless deposition and annealing at different temperatures. Initially, the coating appears dense and amorphous, transforming into worm-like structures through crystallization with MgB2. Higher annealing temperatures lead to brush-like, feathery, and oyster mushroom structures, forming crystalline nickel boron compounds and oxide phases due to synergy. Interestingly, the newly introduced phases disrupt friction patterns nonlinearly, which is linked to MgB2’s ceramic nature and reinforcement quantity. Conversely, incorporating MgB2 and annealing-induced intermetallic phases notably enhances hardness (up to 6) and improves hydrophilicity and antibacterial traits in the coating.
AtıfScopus6WoS4OpenAlex4İncele - MakaleAçık Erişim2024Scopus SJRQ2The Effect of Different Doses of Salt Stress on Germination and Emergence in Cannabis (Cannabis sativa L.) Seed Treated with Pre-Salicylic Acid
Gul, Volkan; Sefaoglu, Fırat; Cetinkaya, Hatice; Dinler, Burcu Seckin
It is known that salinity stress, one of the abiotic stress factors, significantly limits the germination, growth, development, and crop yield of plants. Therefore, this study was conducted to evaluate the effects of salinity (control, 50, 100 ve 150 mM) on seed germination and the effect of salicylic acid (control, 0.25, 0.50, 0.75 ve 1.00 mM) on seed germination to improve salt tolerance in cannabis seeds. The physiological characteristics of the plant, such as germination percentage, germination duration, germination index, radicle length, plumule length, wet radicle weight, dry radicle weight, wet plumule weight, and dry plumule weight, were analyzed. Depending on the salinity application dose, it was observed that there was a significant decrease in the germination parameters of cannabis seeds compared to the control. It was observed that salicylic acid treatments under salinity stress positively affected all the characters examined and reduced germination arrest due to increasing concentration levels. Although it is recommended to prepare seeds with 0.5 mM salicylic acid pre-application dose against salt stress of the cannabis plant,it is essential to expand the studies on its transfer to practice. As a result, salicylic acid will provide positive results that can be transferred to practice by increasing the resistance of cannabis plants against salinity, especially in agricultural soils with salt problems, as it will be more sensitive to pests and diseases.
AtıfScopus4WoS3OpenAlex3İncele - MakaleYalnız künye2024Scopus SJRQ1Effect of oxidation on radiation shielding capacity of ZrNbTaMoW Refractory High Entropy Alloys (RHEA) for nuclear reactor applications: Experimental and theoretical assessment
Sakar, E.; Guler, O.; Alim, B.; Guler, S.H.; Dikici, B.; Lampke, T.
This study presents the production and comprehensive assessment of a Refractory High Entropy Alloy (RHEA) with a ZrNbTaMoW composition for possible usage nuclear reactor applications. The alloy was synthesized using the mechanical alloying (MA) method, and its radiation properties were examined. Elemental powders of Zr, Nb, Ta, Mo, and W were utilized in equimolar quantities during the 120-hour MA process, conducted under a high-purity Ar atmosphere to prevent oxidation. The obtained HEA was then subjected to a mechano-thermal process to transform it into Refractory High-Entropy Oxide (RHEO) for comparing their radiation-shielding performance under oxide conditions. The characterization of the produced alloys through X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron dispersive spectroscopy (EDS). The photon shielding parameters of the alloys were experimentally obtained for various energies emitted from a 133Ba radioactive source, employing a Canberra UltraLEGe semiconductor detector. Furthermore, theoretical calculations were performed to validate the experimental data and to evaluate the alloys' photon shielding capabilities comprehensively. For this purpose, Phy-X/PSD software was employed to determine mass attenuation coefficients, half-value layer, effective atomic number, and effective electron density. Fast neutron absorption capabilities were determined through the calculation of average absorption cross-sections in the 2–12 MeV energy range. The results showed that the oxidation process significantly diminished the photon absorption capacity of RHEA.
AtıfScopus34WoS33OpenAlex37İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ1Enzyme Inhibitory, Physicochemical, and Phytochemical Properties and Botanical Sources of Honey, Bee Pollen, Bee Bread, and Propolis Obtained from the Same Apiary
Gercek, Yusuf Can; Dagsuyu, Eda; Basturk, Fatma Nur; Kırkıncı, Seran; Yıldırım, Nazlıcan; Kıskanç, Gamze; Özmener, Bahar; Unlu, Yigit Sabri; Kalkan, Seda Nur; Boztaş, Kadir
Bee products are an important source of nutrients and bioactive phytochemicals. This study aimed to determine the chemical composition (proximate composition, general phytochemical composition, sugar, and phenolic profiles) of four different products (honey, bee pollen, bee bread, and propolis), obtained from the same apiary, as well as to assess their biological activity through antioxidant and enzyme inhibition assays (α-amylase, α-glucosidase, lipase, AchE, neuraminidase, angiotensin-converting enzyme, urease, trypsin, tyrosinase, carbonic anhydrase, thioredoxin reductase, adenosine deaminase). Clear differences were observed among the samples in terms of both chemical composition and biological activity. The analysis revealed that bee pollen exhibited the highest carbohydrate content (87.9%), while propolis was identified as the richest source of phenolic compounds (14,858.9 mg/kg) among the analyzed samples. Propolis exhibited the highest biological activity in all applied antioxidant assays (CUPRAC, DPPH•, and ABTS•+) and in most enzyme inhibition assays. Notably, the α-glucosidase inhibition activity of propolis was comparable to that of the reference standard. In addition, honey exhibited remarkable trypsin inhibition, also comparable to the applied standard. These findings highlight the diverse bioactivities of hive products, which could play a key role in promoting health and preventing diseases.
AtıfScopus17WoS16OpenAlex16İncele - MakaleAçık Erişim2024Scopus SJRQ2Investigation of Mass Transfer of Ozone in Jet Loop Reactor
Cengiz, Ibrahim; Değermenci, Nejdet; Yildiz, Ergun; Barlak, Melahat Semin
Mass transfer of ozone in a jet loop reactor was investigated in this study. Different parameters such as ozone gas concentration, gas flow rate, circulation flow rate, and spray nozzle diameter were examined for their effect on mass transfer. In experiments with ozone gas concentrations ranging from 3.83 to 17.1 g/m3, the KLa values remained unchanged, with an average of 28.7 ± 2.2 h−1. As the ozone gas concentration increased, the saturation values of ozone in the liquid phase also increased. Experiments were carried out with gas flow rates ranging from 50 to 250 L/h in the jet loop reactor, and increasing gas flow rates increased the KLa value up to five times. When the effect of the liquid circulation flow rate was examined for a spray nozzle diameter of 15.5 mm, increasing the flow rate from 40 L/min to 80 L/min increased the KLa value by approximately 41%. However, the power consumed per reactor volume for this process increased 8 times and reached 2.65 kW/m3. KLa values in the JLR vary between 6.1 and 37.3 h−1 depending on operating parameters and it has been concluded that it performs well compared to its counterparts.
AtıfScopus6WoS6OpenAlex7İncele - MakaleAçık Erişim2024Scopus SJRQ2Antioxidant activity and phenolic composition of propolis from Marmara region, Turkey
Can, Zehra; Kara, Yakup; Kolayli, Sevgi; Çakmak, Ibrahim
This study investigated various properties of raw propolis samples from Marmara region of Turkey. Total phenolic content (TPF), total flavonoid (TFC) values, condensed tannin content (CTC) and phenolic profiles of ethanolic extracts (70%) were analyzed. Antioxidant activities were tested using the Ferric (III) reduction/antioxidant capacity (FRAP) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging methods. Phenolic profiles of the samples were analyzed using high performance liquid chromatography (RP-HPLC-UV) method. TPC, TFC and CTC values in the samples ranged from 52.9 to 203.5 mg GAE/g, 13.6 to 43.9 mg QUE/g, and 2.0 and 2.9 mg CTE/g, respectively. Caffeic acid phenyl ester (CAPE), chrysin, pinocembrin, rutin, and t-cinnamic acid were detected as the common phenolic components in all samples. In conclusion, Marmara region propolis is a rich source of bioactive compounds, especially flavonoids with antioxidant properties.
AtıfScopus14WoS12İncele - MakaleAçık Erişim2024Scopus SJRQ1Efficient bioreduction of 4-phenyl-2-butanone to drug precursor (S)-4-phenyl-2-butanol by a whole-cell biocatalyst using a novel hybrid design technique
Bayhan, Beyzanur; Özdemir, Akın; Dertli, Enes; Şahin, Engin
Asymmetric synthesis is a critical tactic in pharmaceutical industries for creating chiral medications as it allows an enantiomer to be obtained in synthetic chemistry. The asymmetric bioreduction processes by biocatalysts have shown significant potential in producing chiral alcohols. The amount of substrate and the production method of the biocatalytic synthesis of (S)-4-phenyl-2-butanol ((S)-2) are not still desired levels. Furthermore, the biocatalytic asymmetric reduction of 4-phenyl-2-butanone (1) to (R)- or (S)-4-phenyl-2-butanol did not use any mathematical modeling techniques. In this study, the asymmetric bioreduction of 1 was carried out in this work employing Lactobacillus paracasei BD71 biocatalyst and a novel hybrid design-based optimization approach. By using the hybrid design technique, the optimal circumstances were discovered to be pH = 7, temperature = 29 °C, incubation period = 66 h, and agitation speed = 189 rpm. Also, the enantiomeric excess (ee) and conversion could be 99.15 % and 98.19 %, respectively. Next, (S)-2 was acquired to be ee: 99 %, conversion: >99 %, and yield: 97 % from the optimum bioreduction conditions. Furthermore, 14.08 g of 1 under optimal conditions was entirely transformed into (S)-2 (13.84 g, 97 % isolated yield). This study is the first research attempt to use a biocatalyst and an innovative and new hybrid design-based optimization approach to fabricate enantiopure (S)-2 at a high gram scale. This work has successfully demonstrated that the new hybrid design-based optimization technique is applicable to biocatalytic asymmetric reduction processes.
AtıfScopus9WoS8OpenAlex5İncele - MakaleAçık Erişim2024Scopus SJRQ1Investigation of temperature effect on the optimal weight design of steel truss bridges using Cuckoo Search Algorithm
Keleş, Meryem; Artar, Musa; Ergün, Mustafa
In this article, the optimum weight design of steel truss bridges is carried out by considering the effect of temperature. One of the most significant issues such structures may encounter throughout their service life is the extreme temperature changes that can occur for various reasons. If a steel bridge is designed without considering this unfavorable scenario that might arise in the future, significant damage could happen in terms of the usability limit state, and it might even collapse by exceeding its carrying capacity before reaching its service life. Therefore, this study aims to conduct weight optimizations of steel truss bridges, considering the effect of temperature. Thus, it has been revealed how high-temperature variations alter material properties and affect the overall optimum weight of the structure. For this purpose, the minimum-weight designs of three planar steel truss bridges previously analyzed by other researchers have been re-evaluated using the Cuckoo Search Algorithm. The main program containing the flow steps of the algorithm based on the finite element method is coded in MATLAB. Stress and displacement limit values are used as constraints in solving the problems. The optimum weight results for each structure in the case of temperature effect not being considered are relatively similar. Thus, it has been demonstrated that the Cuckoo Search Algorithm can optimize such problems by comparing its results with similar studies in the literature. Then, the analyses are renewed by incorporating the temperature effect using this proven method. When the findings of both cases are examined, it is observed that the optimum weight values for all structures under the influence of temperature increase. This is due to the decrease in the material's modulus of elasticity because of the high-temperature change. In this case, the cross-section is insufficient owing to the loss of rigidity, and larger profiles are needed. The structure's weight tends to increase depending on the severity of the temperature. Also, numerical simulations of the structures under the same conditions are carried out with SAP2000 software to supplement the design optimization analyses detailed above and enrich the research content.
AtıfScopus16WoS13OpenAlex11İncele - MakaleAçık Erişim2024Scopus SJRQ2Mixed series solution for vibration and stability of porous bi-directional functionally graded beams
Turan, Muhittin
A new analytical solution based on the Ritz method is presented in this paper for analyzing the free vibration and buckling behavior of porous bi-directional functionally graded (2D-FG) beams under various boundary conditions. The solution is based on first-order shear deformation theory (FSDT). The selection of solution functions used in Ritz methods distinguishes the methods from each other and determines the accuracy of the analytical solution. To accurately capture the system's behavior and achieve the desired results, these functions have been carefully selected as a combination of polynomial and trigonometric expressions tailored as mixed series functions for each boundary condition. The study considers three types of porosity, namely PFG-1, PFG-2, and PFG-3. The equations of motion are derived using Lagrange's principle, taking into account the power-law variation of the beam material components throughout the volume. The non-dimensional fundamental frequencies and critical buckling loads are calculated for different boundary conditions, gradation exponents in the x and z directions (px, pz), slenderness (L/h), porosity coefficient (e), and porosity types. Initially, the accuracy of the mixed series functions is investigated for non-porous bi-directional functionally graded beams, and the numerical results are compared with existing literature to validate the proposed solution. Subsequently, the paper focuses on analyzing the influence of porosity on the free vibration and buckling behavior of bi-directional functionally graded beams using the developed solution method.
AtıfScopus21WoS22OpenAlex18İncele - MakaleAçık Erişim2024Scopus SJRQ1Physicochemical and structural characterisation of a branched dextran type exopolysaccharide (EPS) from Weissella confusa S6 isolated from fermented sausage (Sucuk)
Özpınar, Fatma Beyza; İspirli, Hümeyra; Kayacan, Selma; Korkmaz, Kader; Dere, Sevda; Sagdic, Osman; Alkay, Zuhal; Tunçil, Yunus Emre; Ayyash, Mutamed; Dertli, Enes
Exopolysaccharide (EPS) producing Lactic Acid Bacteria (LAB) species can be presented in distinct environments. In this study, Turkish fermented sausage (sucuk) was tested for the presence of EPS producer LAB strains and slimy-mucoid colonies were selected for further tests. Among the isolates, Weissella confusa strain S6 was identified and tested for the physicochemical characterisation of its EPS. This strain was found to produce 0.74 g L−1 of EPS in modified BHI medium conditions. Structural characterisation of EPS S6 by 1H and 13C NMR demonstrated that EPS S6 was a highly branched dextran type glucan formed by mainly (1 → 2)-linked α-D-glucose units together with low levels of (1 → 3)-linked α-D-glucose units as branching points. This structure was further confirmed by methylation analysis detected by GC–MS. An average molecular weight of 8 × 106 Da was detected for dextran S6. The FTIR analysis supported the dextran structure and revealed the presence of distinct functional groups within dextran S6 structure. A strong thermal profile was observed for dextran S6 detected by DSC and TGA analysis and dextran S6 revealed a degradation temperature of 289 °C. In terms of physical status, dextran S6 showed amorphous nature detected by XRD analysis. SEM analysis of dextran S6 demonstrated its rough, compact and porous morphology whereas AFM analysis of dextran S6 detected in its water solution showed the irregularity with no clear cross-link within the dextran chains. These technological features of dextran S6 suggests its potential to be used for in situ or ex situ application during meat fermentations.
AtıfScopus25WoS24OpenAlex29İncele - MakaleYalnız künye2024Scopus SJRQ2Middle School Fifth-Grade Students’ Level of Understanding the Concept of Condensation in Different Contexts
Cengiz, Ekrem; Arıcı, Faruk
Evaporation, condensation, and boiling are fundamental concepts taught in science and chemistry classes, closely linked to daily life. These concepts are vital for students to grasp the transformation and conservation of matter, the particulate nature of matter, and related principles. This study evaluated fifth-grade students’ comprehension of condensation across various contexts. The research involved 80 male and 59 female students from a public school in a qualitative phenomenological study. Data analysis utilized the content analysis method. As a result of the study, it was revealed that the students who participated in the research did not understand the concept of condensation sufficiently and could not explain this concept at the desired level in different contexts. Based on the findings, incorporating real-life contexts when teaching the concept of condensation can enhance the understanding of the topic. Moreover, it highlights the significance of an investigative approach to learning new concepts.
AtıfScopus1WoS1OpenAlex2İncele - MakaleYalnız künye2024Scopus SJRQ2The wound healing effect and DNA damage repair of exopolysaccharide extracted from Weissella cibaria MED17
Kahraman-Ilıkkan, Özge; Akad Dinçer, Selin; Bağdat, Elif Şeyma; Çağlar, Işılsu; Dertli, Enes; İspirli, Hümeyra; Şahin, Feride İffet
Lactic acid bacteria can synthesize exopolysaccharides (EPSs), and some of these EPSs have pharmaceutical or medicinal properties. However, the wound healing capacities of EPSs have rarely been reported. In this study, EPS extracted from Weissella cibaria MED17 was used to investigate wound healing capacity. MED17 EPS was previously characterized and antioxidant capacity was also demonstrated. The application dose of the compound was determined by the MTT assay. The comet assay was applied to reveal the free radical scavenging activity and protection capacity of MED 17 against DNA damage by inducing oxidative stress and DNA damage with Mitomycin-C (MMC) in the cells. The comet assay showed that 15 mg/ml MED 17 EPS could ameliorate DNA damage by 50%. Moreover, the scratch test investigated the wound-healing effect of MED 17 EPS on HT-29 colon cells. MED 17 EPS could stimulate the migration of HT-29 and ameliorate MMC-induced DNA damage. However, further studies need to be conducted to clarify the mechanisms of the wound-healing process of MED 17.
AtıfScopus5WoS5OpenAlex5İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ3Antioxidant effect of Rosa pimpinellifolia L. fruit extract on cholestatic liver injury: an experimental study
Demircioglu, Mahmut Kaan; Demircioglu, Zeynep Gul; Cakir, Ozlem; Yanar, Karolin; Ozguven, Muveddet Banu Yilmaz; Atukeren, Pinar; Gulcicek, Osman Bilgin; Citgez, Bulent; Yazici, Pinar
BACKGROUND: Antioxidants have been considered a rational curative strategy to prevent and cure liver diseases involving oxidative stress. An acute obstructive jaundice rat model was established to investigate the in vivo hepatoprotective efficacy of Rosa pimpinellifolia L. METHODS: The experimental jaundice model was performed by binding the main bile duct in 25 male Sprague-Dawley rats. All rats were randomly divided into five groups: first group: laparotomy-sham-only, second group: biliary tract binding (control), and third, fourth, and fifth groups: treatment groups with 250, 500, and 750 mg/kg fruit extracts daily, respectively. RESULTS: Considering dosage, although there was no significant therapeutic effect in the 250 mg/kg of Rosa pimpinellifolia L. group, the best results were found in the 500 mg/kg dose group, while results in the 750 mg/kg dose group showed consistent correlation with proinflammatory response. With regard to biochemical parameters, lipid hydroperoxide level in the rat serum and liver tissue was significantly decreased in all treatment groups. Amadori products, which are one of the early markers of glycol-oxidative stress, showed statistical significance in the treatment. CONCLUSION: It was revealed that the antioxidant effect of Rosa pimpinellifolia L. was more prominent in the early stages of hepatic injury secondary to oxidative stress.
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