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Koleksiyondaki öğeler
- MakaleYalnız künye2014Scopus SJRQ2Geochemical and Sr-Nd isotopic characteristics of Murgul (Artvin) volcanic rocks in the Eastern Black Sea Region (Northeast Turkey)
Sipahi, Ferkan; Sadiklar, M. Burhan; Şen, Cüneyt
The studied volcanic rocks are footwall and hanging wall dacites from the Murgul mine and the surrounding area. Moreover, the hanging wall dacites contain enclaves. Footwall dacite contains biotite, whereas hanging wall dacitic rocks contain hornblende as a ferromagnesian mineral. The enclaves in the hanging wall dacite have sizes that range from 1cm to 20cm and contain hornblende as a ferromagnesian mineral. The volcanic rocks show tholeiitic and transitional affinities. They are rich in large ion lithophile element and light rare earth element with pronounced depletion of high field strength elements. The chondrite-normalized rare earth element patterns (LaN/LuN=1.47-5.12) show low to medium enrichment, which reveal that the rocks were obtained from similar sources in Murgul volcanic rocks. The initial 87Sr/86Sr values range from 0.70442 to 0.70525, and the initial 143Nd/144Nd values range from 0.512741 to 0.512770. The main solidification processes involved in the evolution of the volcanic rocks consist of fractional crystallization with minor amounts of crustal contamination and magma mixing. All geochemical data support that these rocks originated from andesitic magma, and that the parental magma of the rocks were probably derived from an enriched upper mantle, previously modified by subduction-induced metasomatism in a geodynamic setting.
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İncele - MakaleYalnız künye2015Scopus SJRQ4Effectiveness of levamisole and tarantula cubensis extract in the treatment of teat Papillomatosis of cows
Paksoy, Zahid; Gülesci, Nuri; Kandemir, Fatih Mehmet; Dinçel, Güngör Çagdas
Papillomatosis is widespread in cattle and is often observed on the skin of udders. For treatment, anthelmintic, immunomodulator and homeopathic drugs are administered. The objective of the study was to examine the therapeutic effect of levamisole and tarantula cubensis extract in the treatment of papilloma observed in the teats of cows. Sixteen Holstein cows between the age of 2-3 years were used as study material. The cows with Papillomatosis were randomly assigned into two equal groups. The animals in the first group (n=8) were treated with intramuscular double doses of levamisole (5 mg/kg) applied one week apart. The second group of animals (n=8) was treated with two subcutaneous doses of 10 ml of Tarantula cubensis extract one week apart. Four animals in the first group recovered while 8 animals in the second group recovered. The total serum oxidant levels of the animals treated with Tarantula cubensis extract and levamisole on the 15th day was found to be significantly lower than the serum levels of same animals on day 0 of the treatment (P<0.05). The results of this study revealed that tarantula cubensis extract applied in normal therapeutic doses was more effective in the treatment of teat papillomatosis than levamisole.
AtıfScopus7WoS8İncele - MakaleYayıncıda açık erişim2013Scopus SJRQ3Fire analysis of reinforced concrete beams with 2-d plane stress concrete model
Zandi, Yousef; Burnaz, Oguz; Durmus, Ahmet
The main purpose of this study is to investigate the nonlinear response of reinforced concrete beams under standard fire conditions. With this purpose, the 2-D nonlinear structural analysis of a chosen reinforced concrete simple beam is carried out. This beam is exposed to fire form three sides and fixed distributed loads on top of it. In these structural analyses the changes of material properties of concrete and reinforcements according to increasing temperatures are taken into account. Results drawn from these analyses are compared with the results from some simplified methods and put forward some conclusions and recommendations concerning the fire design of reinforced concrete beams.
AtıfScopus1OpenAlex1İncele - DüzeltmeYayıncıda açık erişim2012Scopus SJRQ1Erratum: Probabilistic sensitivity analysis of two suspension bridges in Istanbul, Turkey to near- and far-fault ground motion (Natural Hazards and Earth System Sciences (2012) 12 (459-473))
Çavdar, O.
No abstract available.
- MakaleAçık Erişim2013Scopus SJRQ3Selective Separation, Preconcentration, and Determination of Au (III) Ions in Environmental Samples by Coprecipitation With a 1,2,4-Triazole Derivative
Ozdes, Duygu; Duran, Celal; Serencam, Huseyin; Şahin, Deniz
An effective, simple, lowcost, and accurate separation and preconcentration procedure which has minimal impact on the environment has been developed. It is based on the carrier element-free coprecipitation (CEFC) of Au(III)ions using N-benzyl-2-{[3-methyl-4-(2morpholine-4-ylethyl)-5-oxo-4,5-dihydro-1H-1,2, 4-triazole-1-yl] acetyl)hydrazinecarboxamide (BODAH) as an organic coprecipitant. Determination of the Au(IH) ion levels was performed by flame atomic absorption spectrometry (FAAS). The developed method provided a detection limit of 0.36 μg L-1 and the relative standard deviation for Au(III)ions was found to be 5.1%. Spike tests and certified reference material analyses were performed to validate the method. The developed method was systematically investigated in different sets of experimental parameters that influence the quantitative recovery of the Au(III)ions. Based on these investigations, the optimum conditions for the determination of Au(III) ions at trace levels were established. The coprecipitation method was applied to anodic slime, gold ore, soil, and water samples to determine their Au(III)levels.
AtıfScopus6WoS6OpenAlex3İncele - MakaleYalnız künye2012Scopus SJRQ1Two-Dimensional Geothermal Modelling Along the Central Pontides Magmatic Arc: Implications for the Geodynamic Evolution of Northern Turkey
Maden, Nafiz
The Pontides, which can be divided tectonically into three main segments as Eastern, Central, and Western Pontides, is one of the most complex geodynamic settings within the Alpine belt. The Central Pontides, where the Eastern and Western Pontides met and formed a tectonic knot, represent an amalgamated tectonic mosaic consisting of remnants of oceanic, continental, and island arc segments. Subduction polarity, which is responsible for the formation of the Pontides, is still under debate because of limited geological, geophysical, and geochemical data. Two-dimensional (2-D) thermal modelling studies along the Central Pontides magmatic arc (Northern Turkey), Sakarya and Ki{dotless}rşehir continents are investigated in order to delineate the crustal thermal structure and subduction polarity. The obtained numerical results indicate that arc and back-arc regions are hot because of the cooling effects of a subducting plate. Moho temperatures in the investigated region are found between 992°C in the south (back-arc) and 415°C in the north (arc). Moreover, mantle heat flow values vary from 57.2 mWm -2 in the south (back-arc) to 34.7 mWm -2 in the north (arc). It is shown from this study that the Eurasia plate had moved from north to south under the Anatolia plate along the south Black Sea coast.
AtıfScopus10WoS13OpenAlex12İncele - MakaleYalnız künye2014Scopus SJRQ2A new 5,6-dihydro-2-pyrone derivative from Phomopsis amygdali, an endophytic fungus isolated from hazelnut (Corylus avellana)
Akay, Şeref; Ekiz, Güner; Kocabaş, Fatma; Hameş-Kocabaş, E. Esin; Korkmaz, Kemal S.; Bedir, Erdal
Aims of this study were to isolate endophytes from different parts of hazelnut - Corylus avellana L. to obtain bioactive secondary metabolites and search for the presence of gene region of taxadiene synthase (Ts), a key enzyme in taxol biosynthesis, on selected fungi. Fourteen fungal species were isolated and cultured for the screening studies. The cell-free fermentation broths were extracted with chloroform. The chloroform extracts were tested for cytotoxic activity by MTT method. Based on the activity results and chemical profiles, the isolate identified as Phomopsis amygdali by internal transcribed spaces (ITS) sequence analysis using ITS1 primer was selected for further studies. After large-scale fermentation and purification studies, two major compounds, one of which turned out to be a new secondary metabolite, were isolated and characterized. Structure of the new metabolite was elucidated as (S)-4-butoxy-6-((S)-1-hydroxypentyl)-5,6-dihydro-2H-pyran-2-one by the extensive use of 1D and 2D NMR, and HR-MS, whereas the known compound was identified as (-)pestalotin. Additionally, to evaluate taxol-producing potential of the selected isolate, a PCR amplification study followed by gel electrophoresis analysis was carried out revealing no Ts gene region.
AtıfScopus23WoS18OpenAlex24İncele - MakaleYalnız künye2014Scopus SJRQ1New thiophene-1,2,4-triazole-5(3)-ones: Highly bioactive thiosemicarbazides, structures of Schiff bases and triazole-thiols
Ünver, Yasemin; Sancak, Kemal; Çelik, Fatih; Birinci, Emrah; Küçük, Murat; Soylu, Serkan; Burnaz, Nesibe Arslan
Key compound 2-(4-amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4- tiazole-1-yl) acetohydrazide (3) was synthesized by reacting hydrazine hydrate with ethyl-2-(4-amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4-tiazole- 1yl)acetate (2), obtained in basic media from 4-amino-5-(thiophene-2-ylmethyl)- 2H-1,2,4-triazole-3(4H)-one (1). Compound 3 was converted to thiosemicarbazide derivatives (4a-d) and Schiff base derivatives 6a-e and 7a-e. The treatment of compound 4 with NaOH gave 4-amino-2-((4-(4-aryl)-5-mercapto-4H-1,2,4-triazole-3- yl)methyl)-5-(thiophene-2-ylmethyl)-2H-1,2,4-triazole-3(4H)-ones (5a-d). All newly compounds, well characterized by elemental analyses, IR, 1H NMR, 13C NMR and mass spectral studies were tested for their antioxidant and antimicrobial activities. Thiosemicarbazide derivatives (4a-d) were highly active in two antioxidant tests with 69.0-88.2% DPPH scavenging and 503-1257 μM TEAC values, while the others showed lower or no activity. The results of the two antioxidant tests correlated well. Moreover, Thiosemicarbazide derivatives (4a-d) also showed antibacterial activity against Staphylococcus aureus, Bacillus cereus, and Mycobacterium smegmatis. Thiosemicarbazide group deserves attention in the synthesis of bioactive compounds.
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İncele - Derleme MakaleAçık Erişim2014Scopus SJRQ3Peripheral nerve conduits: Technology update
Arslantunali, D.; Dursun, T.; Yucel, D.; Hasirci, N.; Hasirci, V.
Peripheral nerve injury is a worldwide clinical problem which could lead to loss of neuronal communication along sensory and motor nerves between the central nervous system (CNS) and the peripheral organs and impairs the quality of life of a patient. The primary requirement for the treatment of complete lesions is a tension-free, end-to-end repair. When end-to-end repair is not possible, peripheral nerve grafts or nerve conduits are used. The limited availability of autografts, and drawbacks of the allografts and xenografts like immunological reactions, forced the researchers to investigate and develop alternative approaches, mainly nerve conduits. In this review, recent information on the various types of conduit materials (made of biological and synthetic polymers) and designs (tubular, fibrous, and matrix type) are being presented.
AtıfScopus258WoS241OpenAlex223İncele - MakaleYalnız künye2013Scopus SJRQ3Bay laurel (Laurus nobilis L.) in Japanese quails feeding. 2. Fatty acid content and oxidative stability of breast meat
Karaalp, M.; Genc, N.
In this study, the antioxidant effect of dietary supplementation with bay laurel (Laurus nobilis L.) leaves (LN) to a conventional diet on fatty acid content and oxidatif stability of breast meat was studied. For that purpose, a total number of 60 Japanese quails aged 56-d were fed diets supplemented with 0 (LN0), 2 (LN2) and 4 g (LN4) leaves/kg of feed, respectively. Quails were housed individually in cages during ten weeks. Fatty acid composition was determined for fresh breast meat. Malondialdehyde (MDA) values were determined in breast meat samples stored at +4°C (2, 5 and 8 d) and at -20°C (3 and 6 mo). Supplementation of LN had no effect on any fatty acid content of meat. However, addition of LN lowered (P<0.01) MDA content of the refrigerated meat samples only at 8 d. On the other hand, supplementation with LN had no significant effect on reducing the MDA values of meat samples during the other stored times. Besides, the amount of MDA increased (P<0.01) in all of the refrigerated and frozen meat samples with time. The results of this study demonstrated that supplementation of LN could reduce MDA content of refrigerated meat samples only at 8 d.
AtıfScopus8İncele - MakaleAçık Erişim2015Scopus SJRQ2Controlling spatial forest structure with spatial simulation in forest management planning: A case study from Turkey
Kadiogullari, Ali Ihsan; Baskent, Emin Zeki; Keles, Sedat; Bingöl, Özkan
Decision Support Systems (DSS) is widely used to develop spatially explicit forest management plans through the integration of spatial parameters. As a part of this study, a simulation-based spatial DSS, the ETÇAPSimülasyon program was developed and tested in a case study area. The system has the capability to control the spatial structure of forests based on a geodatabase. Geographical Information Systems (GIS) was used to generate the database, using spatial parameters including opening size, block size and green-up delay in addition to other attribute data such as the empirical yield table and the product assortment table. Based on the simulation technique, a spatial forest management model was developed to link strategic planning with tactical planning on a stand base and to present results with a number of performance indicators. One important component of the model determined all spatial characteristics with spatial parameters and patch descriptions. A stand growth and yield simulation model (BARSM) based on the relationship between current and optimal basal area development was also generated to project future stand characteristics and analyze the effects of various silvicultural treatments. A number of spatial forest management strategies were developed to generate spatially implementable harvest schedules and perform spatial analyses. The forest management concept was enhanced by employing a spatial simulation technique to help analyzing the ecosystem structure. Spatial characteristics for an on- The-ground forest management plan were then developed. The model was tested in Altinoluk Planning Unit (APU) using a spatial simulation technique based on various spatial parameters. The results indicated that the spatial model was able to satisfy the spatial restriction requirements of the forest management plan.
AtıfScopus5WoS3OpenAlex4İncele - MakaleYalnız künye2015Scopus SJRQ2Antifungal effect of Origanum onites essential oil as an alternative to formalin in the artificial incubation of narrow-clawed crayfish (Astacus leptodactylus Eschscholtz, 1823)
Koca, Seval Bahadir; Cevikbas, Mustafa
As alternative to formalin, the antifungal effect of a plant product [Origanum onites L. (Lamiaceae) oil] was investigated for use in the artificial incubation of narrow-clawed crayfish (Astacus leptodactylus Eschscholtz) eggs. For this purpose, this study was conducted as two experiments. In experiment I, the eggs were artificially incubated for 40 days. In experiment II, juveniles were cultured to determine effects of O. onites oil on juveniles for 30 days. The experimental groups were as follows: formalin (3500 ppm for 15 min), O. onites oil (300 ppm for 15 min, 700 ppm for 2 min and 1000 ppm as a dip treatment 15 split-second) and a control (no treatment). In the experiment I, the highest hatching rate (86%) and survival rate of stage II juveniles (80%) were observed in 1000 ppm dip group. These results were similar to that of formalin group (85% and 79%) respectively. The control group exhibited the lowest hatching rate (49%) and stage II rate (42%) compared with the 1000 ppm dip group and 3500 ppm formalin treatments. However, other concentrations (300 and 700 ppm) of O. onites showed toxic effects on the eggs and there was no hatching. In the experiment II, the survival rate and growth performance of the crayfish juveniles were similar in all groups. This study indicated that the 1000 ppm O. onites dip treatment could be a good alternative to formalin for improved egg hatchability in the artificial incubation of crayfish eggs.
AtıfScopus15WoS13OpenAlex14İncele - BildiriYalnız künye2014A note on fractional parabolic differential and difference equations
Ashyralyev, Allaberen; Artykov, Merdan; Cakir, Zafer
In this work, the first and second order of difference schemes that approximately solve the initial-boundary value problem for multidimensional fractional parabolic equation with Dirichlet boundary condition are presented. The stability estimates for the solution of these difference schemes are established.
AtıfScopus5WoS3OpenAlex4İncele - MakaleYalnız künye2013Scopus SJRQ2Solution of time-fractional generalized Hirota-Satsuma coupled KdV equation by generalised differential transformation method
Merdan, Mehmet; Gökdogan, Ahmet; Yildirim, Ahmet; Mohyud-Din, Syed Tauseef
Purpose - In this article, the aim is to obtain an approximate analytical solution of time-fraction generalized Hirota-Satsuma coupled KDV with the help of the two dimensional differential transformation method (DTM). Exact solutions can also be obtained from the known forms of the series solutions. Design/methodology/approach - Two dimensional differential transformation method (DTM) is used. Findings - In this paper, the fractional differential transformation method is implemented to the solution of time-fraction generalized generalized Hirota-Satsuma coupled KDV with a number of initial and boundary values has been proved. DTM can be applied to many complicated linear and strongly nonlinear partial differential equations and does not require linearization, discretization, restrictive assumptions or perturbation. The presented method is a numerical method based on the generalised Taylor series expansion which constructs an analytical solution in the form of a polynomial. Originality/value - This is an original work in which the results indicate that the method is powerful and significant for solving time-fraction generalized generalized Hirota-Satsuma coupled KDV type differential equations.
AtıfScopus19WoS16İncele - MakaleAçık Erişim2011Scopus SJRQ1Modelling and mapping third dimension in a spatial database
Döner, F.; Biyik, C.
In this paper, an overview of phases for modelling and mapping third dimension of spatial objects in a database is presented based on a selected spatial database management system (DBMS). These phases include (1) defining a spatial reference system for representing three-dimensional (3D) objects with real-world coordinates, (2) geometric modelling of 3D objects in the database, (3) 3D spatial indexing for fast accessing/querying the 3D data, 3D spatial queries and representation of 3D data. Then, a case study is performed to assess needs, possibilities and potential limitations of 3D data modelling in the spatial database.
AtıfScopus3WoS4OpenAlex4İncele - MakaleAçık Erişim2011Scopus SJRQ2Mild conditions for oxidation/epoxidation of styrene
Kazanci, A.; Saribiyik, O.Y.; Serin, S.
In this study, in order to obtain novel support materials for immobilization of transition metals, polymeric Schiff bases were synthesized using a poly-condensation reaction between ortho(o-)phthalaldehyde tere(t-)phthalaldehyde, oxaldehyde and diamines like, e.g., ethylene-p- phenylene- and o-phenylenediamine. Additionally, catalytic activity of polymeric Schiff base metal on oxidation/epoxidation of styrene complexes were investigated. The products have been characterized on the basis of analytical and spectral method, Fourier transform infrared spectroscopy, 1H- and 13C-nuclear magnetic resonance, gel-permeation chromatography, elemental analysis, thermogravimetric analysis, atomic adsorbtion spectrometry, gas chromatography and gas chromatography mass spectrometry.
AtıfScopus3WoS3OpenAlex2İncele - MakaleAçık Erişim2011Scopus SJRQ3Factors of land use/cover change: A case study from Turkey
Sivrikaya, Fatih; Çakir, Günay; Akay, Abdullah Emin
Land use/cover change impacts ecosystem services and functions such as forest health, biodiversity, and water production. Monitoring and assessing land use/cover changes provides an effective and accurate evaluation of human impact on the forest ecosystems. This study aims to determine spatial and temporal changes in land use/cover at a particular time period in a typical forest ecosystem of Turkey using geographical information systems (GIS). Specifically, the objective of this study is to analyze the main factors driving land use/cover change and the impacts of such changes in local and global perspective. Results showed that the total forested areas decreased from 5089 ha (41% of the study area) to 4426 ha (36% of the study area) during a 21 year period, which figures a net decrease of 663 ha (5%) forest areas and the average annual deforestation rate was 32 ha. Conifer forest (161 ha) completely transitioned to other cover types over 21-year period. Three major factors including distance from villages, distance from roads, and ground elevation were considered in evaluating forest disturbance. The results showed that these factors influence the reforestation/deforestation rates. Besides, forest disturbance was found to be closely related to distance from villages, distance from roads, and elevation.
AtıfScopus9OpenAlex14İncele - MakaleYalnız künye2011Scopus SJRQ2Laparoscopic abdominoperineal resections for mid or low rectal adenocarcinomas: A retrospective, comparative study
Gezen, Cem; Altuntas, Yunus E.; Kement, Metin; Okkabaz, Nuri; Bilici, Ahmet; Vural, Selahattin; Gumus, Mahmut; Oncel, Mustafa
BACKGROUND: Laparoscopic abdominoperineal resection (APR) has been seldom studied apart from low anterior resections, and deserves to be separately analyzed. This study aims to compare perioperative and oncological outcomes of laparoscopic and conventional APRs performed for the treatment of mid and low rectal adenocarcinomas. MATERIALS AND METHODS: Patients operated for primary mid or low rectal adenocarcinoma between 2001 and 2009 in our institution were retrospectively investigated. These data were abstracted and compared within conventional and laparoscopic resection groups: demographics, tumor and procedure-related parameters, perioperative results, early oncological outcomes, and survival. RESULTS: Demographics and tumor and procedure-related parameters were similar within the laparoscopic (n=31) and conventional (n=36) groups, except intraoperative bleeding and requirement for transfusion, which were significantly lower after laparoscopic APRs. Perioperative results including complication, reoperation, and 30-day mortality rates were identical. Early oncological results and 3-year survival rates were alike. CONCLUSIONS: The perioperative results and oncological outcomes are similar after laparoscopic and conventional APRs. As current data include limited number of patients in a retrospective design, further studies comparing laparoscopic and conventional APR techniques are required.
AtıfScopus8WoS8OpenAlex9İncele - MakaleAçık Erişim2014Scopus SJRQ3Preparation of a new sorbent, cetyltrimethylammonium bromide (CTAB)-modified obsidian, for the separation, preconcentration of Pb(II), Cd(II) ions in food and water samples
Ozdes, Duygu; Duran, Celai
Cetyltrimethylammonium bromide (CTAB)-modified obsidian (CTAB-OB) was utilized as a new sorbent for the separation and preconcentration of Pb(II) and Cd(II) ions by solid phase extraction in some environmental samples prior to their flame atomic absorption spectrophotometric determination. The characterization of CTAB-OB was performed by BET surface area,FTIR and SEM techniques. The effects of significant analytical parameters,including pH of the aqueous solution,eluent type,concentration and volume,CTAB-OB amount,sample volume,adsorption and desorption contact time,were evaluated in detail on the recovery of the analyte ions. The adsorption capacity of CTAB-OB was found to be 48.8 and 43.4 mg g-1 for the Pb(II) and Cd(II) ions,respectively. The detection limits for the analyte ions were 0.89 μg L-1 for Pb(II) and 0.37 μg L-1 for Cd(II),while the relative standard deviations were lower than 3.5% for both of them. In order to ensure the accuracy of the method,certified reference material (CRM-SA-C Sandy Soil C) analyses and spike tests were performed. Then the proposed method was applied to sea and stream water,black tea,and Turkish and import coffee samples to determine their Pb(II) and Cd(II) contents.
AtıfScopus7WoS7OpenAlex7İncele - MakaleAçık Erişim2011Scopus SJRQ1Nonlinear earthquake behaviour of highway tunnels
Sevim, B.
This paper describes the Arhavi Highway Tunnel which has two tubes, its geometrical properties, finite element model, and the nonlinear earthquake behaviour under a huge ground motion considering soil-structure interaction. The Arhavi Highway Tunnel is one of the tallest tunnels constructed in the Black Sea region of Turkey as part of the Coast Road Project. The tunnel has two tubes and each of them is about 1000 m tall. In the study, the modal analyses of the tunnel considering soil-structure interaction are performed and natural frequencies and mode shapes are obtained. Then, nonlinear transient analysis of the tunnel using Drucker-Prager criteria is performed applying acceleration components of 1992 Erzincan, Turkey earthquake's ground motion. In the time history analyses, Rayleigh damping coefficients are calculated using main natural frequency obtained from modal analysis. Element matrices are computed using the Gauss numerical integration technique. The Newmark method is used in the solution of the equation of motion. Because too much memory for the analyses is required, the first 7.5 s of the ground motions, which is the most effective duration, is taken into account in calculations. The displacement and stress results are observed to be the allowable level of the concrete material.
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