Sürdürülebilir Kalkınma Amaçları

Yazarlar

  • MakaleYalnız künye2019Scopus SJRQ1
    Effects of zinc content on strength and wear performance of Al−12Si−3Cu based alloy

    ALEMDAG, Yasin; BEDER, Murat

    The effects of Zn content on strength and wear performance of Al−12Si−3Cu alloy synthesized by gravity casting were systematically investigated. The microstructure and mechanical properties of the alloys were evaluated using OM, XRD, SEM as well as hardness, tension, compression and Charpy impact tests. Their dry sliding wear tests were carried out with a ball-on-disk tester. Microscopic examinations revealed that the microstructure of the base alloy consisted of the α(Al) dendrites, needle-type and coarse Si particles, and CuAl2 (θ) phase. The addition of Zn to this alloy resulted in the formation of α-solid solution phase and the increase of coarse Si particles. The hardness, yield, tensile and compressive strengths, elongation to fracture and impact toughness of the Al−12Si−3Cu−Zn alloys increased with increasing Zn content, but tendency in the tensile and compressive strengths and ductility reversed after adding 1.5%−2% Zn. In addition, the friction coefficient and volume loss of the Al−12Si−3Cu−Zn alloys decreased with increasing Zn content. The study showed that the addition of Zn to Al−12Si−3Cu alloy can improve its potential applications as tribological material.

    AtıfScopus29WoS28OpenAlex32
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  • MakaleAçık Erişim2019Scopus SJRQ2
    Frictionless Contact Problem for a Functionally Graded Layer Loaded Through Two Rigid Punches Using Finite Element Method

    Polat, A.; Kaya, Y.; Bendine, K.; Özşahin, T.Ş.

    In this study, continuous contact problem in the functionally graded (FG) layer loaded with two rigid flat blocks resting on the elastic semi-infinite plane was analyzed by the finite element method. The two-dimensional numerical model of the FG layer was made with the software added to the ANSYS program. This software can be adapted to all contact problem types by making minor changes. The accuracy check of the program was performed by comparing with the analytical solution of the problem by homogeneous layer and its solution by the finite element method. So, fast and practical solutions can be obtained by the developed finite element method on many applications such as; automotive, aviation and space industry applications. The comparisons made showed that the proposed solution gave good results at acceptable levels. In the problem, it was thought that all surfaces were frictionless. The external loads P and Q were transmitted to the FG layer via two flat rigid blocks. Normal stresses between the FG layer and the elastic plane, initial separation loads, initial separation distances and contact stresses under the blocks were investigated for various dimensionless quantities.

    AtıfScopus14WoS14OpenAlex11
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  • Derleme MakaleAçık Erişim2019Scopus SJRQ2
    The importance of antioxidants and place in today’s scientific and technological studies

    Zehiroglu, Cuma; Ozturk Sarikaya, Sevim Beyza

    Antioxidants have become scientifically interesting compounds due to their many benefits such as anti-aging and anti-inflammatory. Today, it is still used in many areas. In food technology, antioxidants are added to many foodstuffs in order to enrich the foods and eliminate the problems. Therefore, studies to determine the antioxidant activities of natural foods and their components are also continuing rapidly. Antioxidants have also been replaced in the encapsulation studies used for the preservation and stabilization of food components. Of course, preservation of foods is as important as their production. The latest packaging techniques for food preservation are edible films and coatings. The protective function of edible films and coatings can be improved by the addition of antioxidants. Unlike these, studies on plants and animals have been investigated in vivo in terms of how the antioxidant activity changes as a result of metabolic activities. The role of antioxidant enzymes in these studies is quite large. Many results have been found for the elimination of diseases by either in vivo or in vitro studies regarding antioxidants. Thus, the importance of antioxidants increased with the use in pharmacology, cosmetics and medicine. In this study, we tried to bring a current perspective to antioxidants played an active role in many fields by combining the technological applications and scientific studies of antioxidants. In order to further customize the issue, we have done this especially for the food and health field and we have tried to emphasize the importance of antioxidants in this way.

    • SDG 2 · Açlığa Son
    AtıfScopus252WoS190OpenAlex273
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  • MakaleAçık Erişim2019Scopus SJRQ1
    A numerical investigation of static resistance of welded planar steel tubular joints under in-plane and out-of-plane bending at elevated temperatures

    Ozyurt, E.; Wang, Y.C.

    This study presents the results of a numerical investigation on static resistance of welded planar steel tubular joints under in-plane and out-of-plane bending moments at elevated temperatures. The numerical simulations were carried out using the commercial finite Element software ABAQUS v6.14-1 and the simulation model was validated by comparing against test results for CHS joints under brace in-plane bending at elevated temperatures. Extensive numerical parametric simulations were performed for CHS/SHS/EHS joints under in-plane and out-of-plane bending at elevated temperatures, to establish a database of results covering a wide range of geometrical parameters, including brace to chord diameter ratio, the angle between brace to chord members, and chord diameter to twice chord thickness ratio. The ratios of joint elevated temperature resistance to ambient temperature resistance were compared to the steel yield strength reduction factor, the steel Young's modulus reduction factor, and the average of the above these reduction factors at different elevated temperatures. Based on the comparisons, it has been found that using the reduction factor for the yield strength of steel to modify the ambient temperature equations will overestimate the resistance of joints at elevated temperatures. As a simplified and safe recommendation, the ambient temperature joint resistance equations can be modified by the average reduction factors for the Young's modulus and yield strength at elevated temperatures. This modification factor can be increased to the yield strength reduction factor when the brace and chord widths/diameters are the same.

    AtıfScopus23WoS19OpenAlex24
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  • MakaleYalnız künye2019Scopus SJRQ2
    Performance Comparison of Various Chicane Types: A Driving Simulator Study

    Aydin, Metin Mutlu; Gunay, Banihan; Akgol, Kadir

    Urban streets are becoming noisy, less safe and unattractive places due to high traffic volumes and vehicular speeds. Especially, high speeds causes many problems such as traffic accidents, noise, etc. To prevent these problems and negative effects of speeding, traffic calming measures have been widely used in many developed countries. In this study, the effectiveness of ten most common chicane types on speed limit compliance were examined by comparing and ranking chicanes according to their performance. For this purpose, a “Safety Index” was developed and an Ordinary Least Square Regression analysis was performed to identify safest chicane types for undivided two-lane and divided four-lane roads by using various parameters. Additionally, statistical tests were conducted to determine the most important driver characteristics of drivers before and inside the chicanes. For the analyses, all necessary data were obtained from the driving tests of 106 volunteers using a driving simulator. For the simulation scenarios, Akdeniz University’s (Antalya/Turkey) campus roads were selected as a case area. The results showed that Chicane Types 2 (CT-2) and 7 (CT-7) have the highest Safety Index values (0.69 and 0.98) and they were found to be the most proper CTs for the undivided and divided roads, respectively. From the statistical tests, it was also found that education level, gender and driving license duration were found to be the statistically significant parameters on speed choice for the most proper chicane types. Additionally, it was concluded that the most important driver characteristics are determined as age (has a negative effect) and gender (to be male has a positive effect) of drivers before and inside the chicanes. All these findings show that the investigation of different CTs has a great potential to reduce speeds and ensure safety in urban minor roads to limit vehicle speeds.

    • SDG 11 · Sürdürülebilir Şehirler ve Topluluklar
    AtıfScopus8WoS8OpenAlex9
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  • MakaleAçık Erişim2019Scopus SJRQ3
    Employees’ opinions on critical success factors and performance criteria in disaster and emergency management

    Sahinoz, Saime; Yaprak, Unal; Sahinoz, Turgut

    Objective: To evaluate the critical success factors at disaster and emergency management and to analyse their impact on performance to guide the managers and decision makers. Methods: This was a cross-sectional study. It included all staff working in the fire brigade, 112 Emergency, Disaster and Emergency Management Authority and Red Crescent institutions serving in emergency situations in five provinces (Rize, Artvin, Trabzon, Gümüşhane, Bayburt) in the Eastern Black Sea region of Turkey. One province (Gümüşhane) was selected by cluster sampling method. Questionnaire which is the data collection method in the study was applied between 08/01/2016-02/02/2016 to all of the staff working in the fire brigade, 112 Emergency, Disaster and Emergency Management Authority and Red Crescent institutions serving in emergency situations in Gümüşhane province. Results: It has been found out that there is a significant and positive relationship between all of the critical success factors, planning, response and recovery criteria, and performance variance. Conclusions: The presence of well-planned emergency aid systems in the institutions or organizations involved in this area is an element of success. For this reason, this factor should be given more importance.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus2WoS2OpenAlex2
    ScopusWeb of SciencePubMedİncele
  • MakaleAçık Erişim2019Scopus SJRQ2
    Centaurea hypoleuca DC: Phenolic content, antimicrobial, antioxidant and enzyme inhibitory activities

    Özcan, Kadriye; Acet, Tuba; Çorbacı, Cengiz

    Centaurea hypoleuca is one of the plants have been traditionally used in treatments of many diseases in folk medicine in Turkey. In the present study, ethanol, methanol, and ethyl acetate extracts of the plant's aerial parts were examined and their antioxidant, antimicrobial, and enzyme inhibition activities were determined for the first time. The antioxidant assays were performed in vitro using ABTS and DPPH methods, whereas the antimicrobial efficiency was determined using disc diffusion and microdilution methods. Moreover, the enzyme inhibition activity was analyzed using calorimetric methods targeting the key enzymes used in the treatment of Alzheimer's disease (cholinesterase) and diabetes (glucosidase and amylase). Also, the phenolic contents were analyzed using HPLC. The biological activity of flower ethyl acetate extract was found to be significantly higher than those of other extracts. This extract was more prominent because of its strong antimicrobial activity with the MIC value of 8 µg mL−1 against MRSA. Moreover, the main components of the extract were determined to be catechin and chlorogenic acid. In conclusion, these results indicate that C. hypoleuca can be pharmaceutically used as herbal remedies for its antioxidant, antimicrobial, and enzyme inhibitor effects.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus35WoS31OpenAlex39
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  • MakaleYalnız künye2019Scopus SJRQ1
    Examining the effect of “Shotblocker” in relieving pain associated with intramuscular injection

    Aydin, Esra; Avşar, Gülçin

    This study was conducted in order to examine the effect of “Shotblocker” in relieving pain associated with intramuscular injection. The population of the study consisted of all the patients who were hospitalized in the hospital and received intramuscular diclomec treatment. In order to eliminate the individual pain differences, each patient constituted their own control group. Patient Information Form, Visual Analogue Scale (VAS), and Shotblocker were used to collect the data. Pain level of the patients was measured by using VAS within the first minute after the injection. The pain mean score of the patients was 1.22 ± 0.62 in the experimental group and 2.48 ± 1.12 cm in the control group and the difference between them was statistically significant (p < 0.001). Shotblocker was determined to be effective on relieving pain associated with intramuscular injection.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus29WoS21OpenAlex32
    ScopusWeb of SciencePubMedİncele
  • MakaleYalnız künye2019Scopus SJRQ3
    Determining tourists’ propensity to consume innovative cuisine: the case of molecular cuisine

    Akyürek, suat; Kızılcık, onur

    In this research, which was carried out in order to obtain findings that will contribute to determine touristic product development and promotion strategies of tourism establishments serving for food and beverage industry, tourists’ propensity to consume molecular cuisine were reviewed. Moreover, it was tested whether or not there was difference between tourists’ propensity to consume molecular cuisine according to some socio-demographic variables in order to obtain indicative findings for tourism marketers within the scope of demographic segmentation which is among the market segmentation strategies. The data obtained from the research was reviewed and then reliability analysis, frequency analysis, t test, and one-way variance analysis were performed on the data. Finally, theoretical and practical implications of this study were discussed.

    AtıfScopus5WoS4OpenAlex7
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  • MakaleYalnız künye2019
    A STUDY ON THE CHARACTERISTICS OF GÜMÜŞHANE SEISMICITY: ANALYSES OF REGION-TIME PARAMETERS

    Öztürk, Serkan; Kaya, Aynur

    The proposed study is focused on the identification of region-time characteristics of earthquakes in Gümüşhane, Turkey. Detailed statistical evaluations were achieved by considering the most frequently used size-scaling parameters such as seismotectonic b-value, fractal dimension Dc-value, standard normal deviate Z-value and recurrence time of earthquakes. Used earthquake catalog is homogeneous for duration magnitude, Md, and consists of 2902 shallow earthquakes with 1.0≤Md≤6.5 in about 47.76-years period between 1970 and middle of 2018. b-value is computed as 1.02±0.02 with a completeness level of 2.8, and this result indicates that frequency-magnitude distribution of seismicity in Gümüşhane is well represented with a b-value typically close to 1.0. Dc-value is calculated as 1.57±0.03 with a scale invariance between 4.96 and 86.28 km. This Dc-value means that seismic activity is more clustered in smaller areas or at larger scales in Gümüşhane. The analysis on the recurrence times of earthquakes implies that Gümüşhane has not a significant earthquake potential for the great earthquakes. Regional variation of b-value shows that small bvalues were observed in and around Kelkit and Köse, and these regions may have a possible earthquake hazard and risk in the future. Z-value analysis suggests that there are not noticeable seismicity rate changes in the mid-2018. These statistical results indicate that the seismic hazard is low and seismic risk is minor in the intermediate term in Gümüşhane.

    AtıfScopus3WoS2
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  • Derleme MakaleAçık Erişim2019Scopus SJRQ4
    A Review Study on the Using of Diethyl Ether in Diesel Engines: Effects on CO2 Emissions

    Sezer, İsmet

    Vehicle and other fuel combustion emissions can change the composition of the atmosphere, increasing its ability to trap heat. Gases that are effective in trapping heat are called greenhouse gases and include all of the gases in vehicle emissions. The major component of greenhouse gases emissions is carbon dioxide (CO2). Reduction of CO2 emissions has become a concern worldwide. Introduction of biofuels to fueling of automotive engines is the one method to decrease emissions of greenhouse gases. The CO2 from biofuels, is emitted during combustion and absorbed during growth of tree end plants. These biofuels can be applied as blends or sole fuels. The most researches declare that the best way to reduce greenhouse emissions is the use of various biofuels. Therefore, it is very important that the results of various studies on alternative fuels or fuel additives are evaluated together to practice applications. On the other hand, diesel cars are also helping to reduce CO2 emissions. For these reasons, this study especially focuses on the use diethyl ether in diesel engines as fuel or fuel additive in various diesel engine fuels. This review study investigates the effects of diethyl ether addition on the CO2 emissions.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 13 · İklim Eylemi
    AtıfScopus5WoS7OpenAlex7TR Dizin2
    ScopusWeb of ScienceTR Dizinİncele
  • MakaleYalnız künye2019Scopus SJRQ1
    Valorisation of fruit by-products: Production characterization of pectins from fruit peels

    Güzel, Melih; Akpınar, Özlem

    The aim of the study is to determine the physical, chemical, structural and thermal properties of the pectins obtained from melon rinds, kiwifruit and pomeganate peels and compared with the pectins obtained from apple and orange peel used in the commercial pectin production process. Pectins extractions from these wastes were performed with citric acid, at 80 °C and 60 min. All pectins, extracted, were found to be high methoxyl pectines. The water holding capacity of the melon rind, kiwifruit and pomegranate peels pectins were lower than the orange and apple peel pectins while the thermal stability of the kiwifruit peel pectin was close to the apple and orange peel pectins. The morphological structures of the extracted pectins showed that they had micro-fractures and hollow openings. The crystallinity of the melon rinds, kiwifruit and pomegranate peel pectins were smilar to orange peel pectin. The result of this study showed that the kiwifruit peel had advantages in terms of commercial pectin production due to its high pectin yield, water holding capacity, esterification degree and thermal stability.

    • SDG 2 · Açlığa Son
    • SDG 12 · Sorumlu Üretim ve Tüketim
    AtıfScopus207WoS180OpenAlex224
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  • MakaleYalnız künye2019Scopus SJRQ2
    Effects of Kefir on Quality of Life and Sleep Disturbances in Postmenopausal Women

    Özcan, Handan; Oskay, Ümran; Bodur, Ali Fuat

    The aim of this study is to identify the effects of kefir, an alternative treatment method, on quality of life and sleep disturbances in postmenopausal women. In this study, it is seen that kefir has positive effects on sleep disturbances, depression, and quality of life in postmenopausal women.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus19WoS17OpenAlex22
    ScopusWeb of SciencePubMedİncele
  • MakaleYalnız künye2019Scopus SJRQ2
    TLD characteristic of glass, feldspathic and lithium disilicate ceramics

    Isik, Esme; Toktamis, Huseyin

    Thermoluminescence (TL) emission of dental ceramics could be potentially used for retrospective dosimetry purposes as this allows a quick and reliable dose assessment in case of nuclear accident or bad use of a nuclear attack. This paper reports on the chemical and luminescence characterization of glass, feldspathic and lithium disilicate glass ceramic (LS2). Swedish and Turkish dental ceramics supplied by Vivadent Ivoclar considering: (i) the dose response in the range 10 Gy to 6.9 kGy which displays a linear dose−response at low dose values up to 36 Gy (glass and feldspathic ceramics) and shows sublinear behavior from 12 Gy to 6 kGy (lithium disilicate glass ceramics), (ii) a reproducibility of the TL signal in which the area under the glow curve increased about 25% after 10 cycles for glass and lithium disilicate ceramics and increased about 30% after seven cycles for feldspathic ceramics, (iii) stability of the luminescence emission with the elapsed time and (iv) effect of the heating rate. Glass, lithium disilicate and feldspathic ceramics display a complex UV-blue glow emission that can be respectively fitted to five and four groups of components assuming first-order kinetics behavior.

    AtıfScopus5WoS4
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  • MakaleAçık Erişim2019Scopus SJRQ3
    The effect of interest rate on output level and inflation in Turkey: Evaluation of monetarist and new keynesian perspective

    Akbas, Yusuf Ekrem; Sancar, Canan

    In this paper, the relationship between inflation-interest rate and output level for the period between 2000M1-2015M12 in Turkey is evaluated in terms of Monetarist and New Keynesian perspective. These relationships among the variables are analysed through linear and non-linear methods. As a result of the analysis, it is concluded that the interest rate does not have a significant effect on the output level. Also, it was determined that there is a short-term as well as a long-term negative relationship from the interest rate towards inflation. It was concluded that the monetary policy cannot affect the real output, but the inflation. These results show that the Monetarist perspective is more valid for the post 2000 period in Turkey.

    AtıfScopus3WoS2OpenAlex3
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  • MakaleYalnız künye2019Scopus SJRQ1
    Estimating the number of clusters in a dataset via consensus clustering

    Ünlü, Ramazan; Xanthopoulos, Petros

    In unsupervised learning, the problem of finding the appropriate number of clusters -usually notated as k- is very challenging. Its importance lies in the fact that k is a vital hyperparameter for the most clustering algorithms. One algorithmic approach for tacking this problem is to apply a certain clustering algorithm with various cluster configurations and decide to use the one that maximizes a certain internal validity measure. This is a promising and computationally efficient approach since the independent runs are parallelizable. In this paper, we attempt to improve over this estimation approach by incorporating a consensus clustering approach into k estimating scheme. The weighted consensus clustering scheme employs four different indices namely Silhouette (SH), Calinski–Harabasz (CH), Davies–Bouldin (DB), and Consensus (CI) indices to estimate the correct number of cluster. Computational experiments in a dataset with clusters ranging from 2 to 7 show the profound advantages of weighted consensus clustering for correctly finding k in comparison to individual clustering method (e.g, k-means) and simple consensus clustering.

    AtıfScopus136WoS111OpenAlex139
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  • MakaleYalnız künye2019Scopus SJRQ1
    A statistical space-time-magnitude analysis on the aftershocks occurrence of the July 21th, 2017 M W  = 6.5 Bodrum-Kos, Turkey, earthquake

    Öztürk, Serkan; Şahin, Şakir

    In this study, a detailed space-time-magnitude assessment on the aftershock sequence of July 21th, 2017, M W 6.5, Bodrum-Kos earthquake (Turkey) is carried out by focusing on the analyses of aftershock parameters: b-value, p-value, Dc-value and Mamax. b-value is estimated as 0.90 ± 0.05 with a completeness magnitude Mc = 1.6 and this relatively small b-value may be resulted from the abundance of aftershocks with magnitude M L ≥ 4.0. However, it is well represented by the Gutenberg-Richter law with a typically b ≈ 1.0. p-value is estimated as 1.04 ± 0.02 with a c-value = 0.224 ± 0.039 and is well characterized nearly close to the global p ≈ 1.0. This relatively high p-value may be a result of the relative fast decay rate of the aftershock activity. Dc-value is calculated as 1.74 ± 0.09 and it means that aftershocks are homogeneously distributed. Temporal distribution of b-value shows that small b-values may be due to a stepwise increase in effective stress before the occurrence of larger aftershocks. Regional changes range from 0.5 to 1.2 in b-value, from 0.4 to 1.3 in p-value and from 3.0 to 5.2 in Mamax. The smallest b-values are found in and around mainshock, including Karaada, Bodrum, Akyarlar and Turgutreis, and these regions have high stress as well as coseismic deformation. The largest p-values are found in and around the mainshock epicenter including Karaada, and it is interpreted that this situation may be caused by coseismic deformation. Mamax values larger than 4.4 are observed in and around mainshock epicenter, including Bodrum and Akyarlar, and there is a clear correlation between spatial variations of b-values and Mamax. These results show that stress changes and coseismic deformation seem highly effective on b and p-value variations. Therefore, a special interest needs to be given to these anomaly regions since aftershock hazard is highly associated with these parameters and may be developed considering their space-time-magnitude distribution.

    AtıfScopus27WoS20OpenAlex22
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  • BildiriYalnız künye2019
    Design of a MATLAB GUI for Day Ahead Forecasting of PV Panel Power

    Bektas, Sibel Cevik; Cakmak, Recep; Altas, Ismail H.

    This paper introduces design and utilization of a MATLAB graphical user interface (GUI) platform to forecast day ahead hourly Photovoltaic (PV) panel power by using forecasted day ahead global horizontal solar radiation. This platform, which would be a useful and practical tool for researchers who are study on energy management, planning and forecasting studies, consists of three parts. The first part predicts day ahead global horizontal solar radiation by trained artificial neural network (ANN) model. The second part performs the calculation of solar irradiation on the module, which has a tilted angle according to forecasting solar radiation data. The last part estimates the power generated by PV panel according to the calculated incident radiation. In this study, the solar irradiation forecasting, the calculation of incident radiation to tilted module and prediction of the solar power to be generated by the PV module are done. The designed GUI has been utilized to forecast solar radiation and PV output power for test days. Then obtained forecasted data have been evaluated with mean absolute percentage error (MAPE) and correlation coefficient (R).

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 13 · İklim Eylemi
    AtıfScopus4OpenAlex5
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  • MakaleAçık Erişim2019Scopus SJRQ1
    Petrology and 40Ar-39Ar dating of paragneisses from the Devrekani Massif (Central Pontides, Northern Turkey): Implications for the Jurassic high-T metamorphism in an extensional tectonic environment

    Gücer, Mehmet Ali; Arslan, Mehmet; Çimen, Okay; Sherlock, Sarah C.

    The Devrekani Massif in the northern part of the Central Pontides (Northern Turkey) provides important clues to the regional tectonics and geodynamic processes associated with Jurassic high grade metamorphic conditions. This study reports new paragenetic assemblages, mineral compositions, whole-rock geochemistry and 40Ar-39Ar geochronological data from the paragneisses in the massif, and, discusses the P–T conditions and geodynamic implications of the Jurassic metamorphism during continental extension in the Central Pontides. Upper amphibolite to lower granulite facies paragneisses form one of the main lithological units in the massif. Within these, there are five different mineral parageneses with diagnostic mineral assemblages of: quartz, K-feldspar (An0-1Ab4-26Or73-96), plagioclase (An18-35), biotite [XPhl: 0.28–0.57; Mg/(Mg + Fe2+): 0.33–0.61], sillimanite, cordierite [Mg/(Mg + Fe2+): 0.48–0.71] and garnet (Alm43-80Grs0-18Prp5-23And0-4Sps10-33) with minor hercynite. Based on Na-in-Crd thermometry and GASP barometry results, the peak metamorphic conditions are 775 ± 25 °C and 6 ± 1 kbar in the massif. The field relations, petrography and bulk chemical data suggest that the paragneisses, derived from shale-wackestone and pelitic sedimentary protoliths, are typical rock lithologies of an active continental margin. They display enrichments in LILE over HFSE, coupled with negative Nb and Ti anomalies, which are geochemical signatures of subduction-related sources. It is likely that the peak metamorphism took place during the Middle–Upper Jurassic period (ca. 174–156 Ma), suggesting that the metamorphic rocks cooled to 300–350 °C at ca. 156 Ma. The mineral assemblages reveal that the prograde history passed from sillimanite zone conditions up to the cordierite-garnet-K-feldspar zone. The petrological and geochronological data indicate that the protoliths are related to multiple sources such as volcano-sedimentary successions. We conclude that the Devrekani Massif represents the products of pre-Jurassic sedimentation, and Permo-Carboniferous continental arc magmatism, overprinted by Jurassic metamorphism.

    AtıfScopus9WoS10OpenAlex6
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  • MakaleAçık Erişim2019Scopus SJRQ3
    Reduced Akkermansia muciniphila and Faecalibacterium prausnitzii levels in the gut microbiota of children with allergic asthma

    Demirci, M.; Tokman, H.B.; Uysal, H.K.; Demiryas, S.; Karakullukcu, A.; Saribas, S.; Cokugras, H.; Kocazeybek, B.S.

    Introduction and objectives: The amounts of Akkermansia muciniphila and Faecalibacterium prausnitzii in gut microbiota are reduced in patients with allergic diseases compared to healthy controls. We aimed to quantify levels of A. muciniphila and F. prausnitzii amounts using real-time quantitative PCR (qPCR) in the gut microbiota of children with allergic asthma and in healthy controls. Materials and methods: In total, 92 children between the ages of three and eight who were diagnosed with asthma and 88 healthy children were included in the study and bacterial DNA was isolated from the stool samples using the stool DNA isolation Kit. qPCR assays were studied with the microbial DNA qPCR Kit for A. muciniphila and microbial DNA qPCR Kit for F. prausnitzii. Results: Both bacterial species showed a reduction in the patient group compared to healthy controls. A. muciniphila and F. prausnitzii were found to be 5.45 ± 0.004, 6.74 ± 0.01 and 5.71 ± 0.002, 7.28 ± 0.009 in the stool samples of the asthma and healthy control groups, respectively. Conclusions: F. prausnitzii and A. muciniphila may have induced anti-inflammatory cytokine IL-10 and prevented the secretion of pro-inflammatory cytokines like IL-12. These findings suggest that A. muciniphila and F. prausnitzii may suppress inflammation through its secreted metabolites.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus143WoS133OpenAlex149
    ScopusWeb of SciencePubMedİncele