Gümüşhane ÜniversitesiGümüşhane ÜniversitesiAçık Erişim Arşivi · RDL Open

Sürdürülebilir Kalkınma Amaçları

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Yeniden eskiyeEskiden yeniye
  • MakaleAçık Erişim2011
    Solving a fractional order model of HIV infection of CD4+ T cells

    Gokdogan, Ahmet; Yildirim, Ahmet; Merdan, Mehmet

    In this paper, a multi-step differential transform method (MsDTM) is performed to give approximate and analytical solutions of nonlinear fractional order ordinary differential equation systems such as a model for HIV infection of CD4+ T cells. The numerical solutions obtained from the proposed method indicate that the approach is easy to implement and accurate when applied to systems of fractional differential equations. Some figures are presented to show the reliability and simplicity of the methods.

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  • MakaleAçık Erişim2011
    Geochemical and Sr-Nd isotopic characteristics of post-collisional calc-alkaline volcanics in the eastern pontides (NE Turkey); [Doǧu Pontidlerde (KD Türkiye) Çarpişma Sonrası Kalk-Alkalen Volkanizmanın Jeokimyası ve Sr-Nd İzotopik Karakterleri]

    Kaygusuz, Abdullah; Arslan, Mehmet; Siebel, Wolfgang; Şen, Cüneyt

    Major, trace element, K -Ar age and Sr-Nd isotopic data are presented for the Eocene Torul volcanics in the eastern Pontide orogenic belt (NE Turkey). The studied rocks are composed of basaltic andesitic, andesitic, trachyandesitic, and minor trachydacitic lavas associated with their pyroclastics. These rocks contain plagioclase (An2-44), hornblende (Mg#= 0.78-0.98), clinopyroxene (Wo43-46 En41-43 Fs10-15), biotite, quartz, and minor sanidine phenocrysts. K-Ar ages on hornblendes ages range from 43.99 (±2.59) to 33.45 (±2.32) Ma, within the Middle to Late Eocene. The volcanic rocks show calc-alkaline affinities and have medium to high K contents. They are enriched in large ion lithophile (LILE) and light rare earth elements (LREE), with pronounced depletion of high field strength elements (HFSE). The chondrite-normalized REE patterns (Lacn/Lucn= 4.0-9.8) show low to medium enrichment, indicating similar sources for the rock suite. Initial 87Sr/86Sr values vary between 0.70457 and 0.70511 and initial 143Nd/144Nd values between 0.51264 and 0.51278. The main solidification processes involved in the evolution of the volcanics consist of fractional crystallization with minor amounts of crustal contamination ± magma mixing. All evidence supports the conclusion that the parental magma(s) of the rocks probably derived from an enriched upper mantle, previously modified by subduction- induced metasomatism in a post-collisional geodynamic setting.

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  • MakaleYalnız künye2011
    Theoretical analysis the use of dimethyl ether and diethyl ether in a diesel engine

    Sezer, Ismet

    In this study, the use of dimethyl ether (DME) and diethyl ether (DEE) in diesel engines as alternative fuels investigated. A commercial suction (naturally-aspirated) direct injection (SDI) automobile diesel engine was chosen for investigation. Thermodynamic and performance analysis has been performed via a thermodynamic diesel engine cycle model. Thermodynamic and performance parameters computed and compared for diesel, DME and DEE fuels at two different situations. Results showed that DME and DEE presented the lower cylinder temperature and pressure, so a lower engine performance than diesel fuel for equal injection conditions. Brake power decreases about 32.1% and 19.4% at 4200 rpm while brake specific fuel consumption increases about 47.1% and 24.7% at 2200 rpm for DME and DEE, respectively. However, engine performance of DME and DEE extensively improves for the equal equivalence ratio condition, although more amount of fuel injection about 64 percent for DME and 32 percent for DEE is essential. The increments obtained by DME and DEE are about 13.6% and 6% in brake power at 4200 rpm compared to diesel. Brake specific fuel consumption is still higher about 43.5% for DME and 23.6% for DEE than diesel. Brake thermal efficiency of DME and DEE is generally better than diesel fuel.

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  • MakaleAçık Erişim2011
    Heparin for adhesion prevention: Comparison of three different dosages with Seprafilm in a murine model

    Kement, Metin; Censur, Zafer; Oncel, Mustafa; Buyukokuroglu, Mehmet E.; Gezen, Fazli C.

    Background: This study aimed to assess the safety and effectiveness of different dosages of heparin for adhesion prevention by comparing with Seprafilm®, in a murine model. Materials and methods: Seventy five Balb/c mice were randomized into five groups. Group C were reserved as controls, and 62.5 IU, 125 IU, 250 IU of heparin, and Seprafilm® were intraperitoneally applied in studied groups. The severity and locations of adhesions were assessed after the sacrification on day 14. The cause of death was investigated to evaluate the side effects of the drugs. Results: The death of 2 subjects due to peritonitis (1 in Group C, 1 in Group H62.5) left 14 subjects in Group C and Group H62.5 (P ≥ 0.05), and no hemorrhage related death was observed. The use of the products significantly reduced the severity score of adhesion and the number of animals, had adhesions in different locations of the abdominal cavity, when the results were compared with the control group (P < 0.05 for all comparisons). Higher dosages of heparin seemed to be more effective. The results in group S, groups H250 and H125 were quite similar. Conclusions: Relatively high doses (125 IU and 250 IU) of intra-abdominal heparin may be comparable in safety and effectiveness to Seprafilm® in adhesion prevention in mice.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
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  • BildiriAçık Erişim2011
    Core competences in non-governmental organizations: A case study

    Besler, Senem; Sezerel, Hakan; Ozsahin, M

    The aim of this study is to suggest the importance of core competences in the success of nongovernmental organizations. Accordingly, an answer is searched regarding with which activities successful non-governmental organizations can sustain their lives, and whether the core competencies are influential in this success. Çaǧdas. Drama Derneǧi (Contemporary Drama Association), a nongovernmental organization which has continued its activities by competing with profit organizations in the field of creative drama in Turkey for twenty years has been examined in depth with the sample case method. The examination has been conducted through interviews, archive scanning and participant observation. The works of the association have been observed on-site and by participating in the activities, the obtained data have been evaluated within the scope of the research. Its core competence, decision making groups of the society in the domain of education and arts, its other nongovernmental organizations, led by higher education institutions have come forth as establishing result-oriented relationships and relationship management. It is considered that the core competency of the organization, as differentiating competitive ability and competitive power, has provided a competitive edge over its competitors.

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  • MakaleYalnız künye2011
    Effects of kale (Brassica oleracea L. var. acephala DC) leaves extracts on the susceptibility of very low and low density lipoproteins to oxidation

    Kural, Birgül Vanizor; Küçük, Nurçin; Yücesan, Fulya Balaban; Örem, Asim

    Of Brassicaceous plants, kale (Brassica oleraceae L. var. acephala DC) contains polyphenols, flavonoids, isoflavones and glucosinolates and so has antioxidant and anticarcinogenic properties. Antioxidants inhibit negative effects of free radicals and may, therefore, protect tissues against oxidative damage. Oxidation of lipoproteins is a key event in the development of atherosclerosis. In the current study, the levels of total phenolic and flavonoid contents and total antioxidant capacity of methanolic and aqueous extracts of kale leaves were determined. In addition, the susceptibility of isolated lipoproteins - very low density lipoprotein (VLDL) and low density lipoprotein (LDL) to the Cu 2+-induced oxidation with various concentrations of metanolic and aqueous extracts was evaluated as t-lag values. Although aqueous extract had higher total antioxidant capacity, methanolic extract had higher total phenolic and flavonoid content (P<0.05). On the other hand, both extracts inhibited lipid peroxidation in both isolated VLDL and LDL. Inhibitory effect of extracts or increasing t-lag values, mainly in methanolic extract was found to be related to increasing the concentration of extracts. It was concluded that because of high antioxidant capacity and phenolic content, kale showed a protective effect on the oxidation of lipoproteins. Therefore, it may be speculated that kale consumption may play an important protective role in the cardiovascular and other related diseases resulting from imbalance of oxidant and antioxidant status.

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  • MakaleAçık Erişim2011
    The first record of the genus Odiellus (opiliones, phalangiidae) in Turkey with some SEM studies on its morphology

    Kurt, K.; Erman, O. Köksal

    The harvestmen species Odiellus lendli (Soerensen, 1894), with its genus Odiellus Roewer, 1923, was found in Anatolia. It represents a new record of Turkish harvestmen fauna. The characteristic features of this species are described and illustrated. Scanning electron microscopy (SEM) studies on the dorsal integument, ventral habitus, chelicerae, pedipalpus, trident, the ocularium and legs of female specimens are also presented. Localities of the collecting sites are photographed and plotted on a map.

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  • MakaleYalnız künye2011
    A proficiency test scheme for the quality control of black tea and development of quality control material for internal quality control

    Baltaci, Cemalettin; Ilyasoǧlu, Huri; Sarikaya, Sevim Beyza Öztürk; Cavrar, Sevda; Yayli, Nurettin

    A proficiency test (PT) was organized for quality control analysis of black tea. Test materials for the analyses of total content of powder tea, moisture, total ash, acid-insoluble ash, water-soluble ash, alkalinity of water-soluble ash, water extract, crude fiber and caffeine were sent to the participant laboratories (n:43) in 2009. The assigned value, standard deviation of the parameters and z-scores of the participant laboratories were calculated using the data reported by the participants. The percentage of the reported results for analytes was found to be ranged from 67.5 to 100%. Acceptable z-scores were achieved by 80.5-97.5% of the participant laboratories. More than 15% of unacceptable results were obtained for acid-insoluble ash and caffeine analyses. The quality control material for quality control analysis of black tea was developed from the remaining material.

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  • MakaleYalnız künye2011
    Polyphenol contents and antioxidant properties of medlar (Mespilus germanica L.)

    Gülçin, Ilhami; Topal, Fevzi; Sarikaya, S. Beyza Öztürk; Bursal, Ercan; Bilsel, Gökhan; Gören, Ahmet C.

    Medlar is the fruit of Mespilus germanica L. in the family of Rosaceae. The present study outlines that the native medlar (Mespilus germanica L.) fruits an extremely rich source of antioxidants. In this study, antioxidant and antiradical property of medlar fruits were evaluated. Total phenolics and flavonoids amounts in lyophilized extract of medlar (LEM) fruits were calculated as gallic acid and quercetin equivalents, respectively. Antioxidant and radical scavenging activity of LEM were investigated using different in vitro assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH·), N,N-dimethyl-p-phenylenediamine (DMPD•+), and superoxide anion radicals (O2•-) scavenging activity, hydrogen peroxide (H2O2), ferric ions (Fe 3+) and cupric ions (Cu 2+) reducing ability, Fe 3+ -TPTZ reducing ability, ferrous ions (Fe2+) chelating activity as trolox equivalent. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid and ascorbic acid in LEM were detected by high performance liquid chromatography and tandem mass spectrometry (LC-MS/MS). The presence of these antioxidant compounds can be considered as a quality parameter for edible medlar fruits.

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  • MakaleAçık Erişim2011
    Early abyssal- and late SSZ-type vestiges of the Rheic oceanic mantle in the Variscan basement of the Sakarya Zone, NE Turkey: Implications for the sense of subduction and opening of the Paleotethys

    Dokuz, Abdurrahman; Uysal, Ibrahim; Kaliwoda, Melanie; Karsli, Orhan; Ottley, Chris J.; Kandemir, Raif

    The boundary between the Gondwana and Laurussia, or a terrane separated from it, is traced by a suture recording the closure of the Rheic ocean in the Pulur, Beyçam and Kurtoǧlu areas of the eastern Sakarya Zone of Turkey. Pulur lherzolite has a lower Cr# [100Cr/(Cr+Al)=5-37] of the spinel and slightly enriched flat medium-heavy rare earth element (M-HREE) whole-rock pattern typical for those of the fertile abyssal-type lherzolite. By contrast, the Beyçam harzburgite displays the mineralogical and geochemical features of a moderately depleted residue at a supra subduction zone (SSZ). Some of spinels from the Beyçam peridotites show TiO2 contents (0.15-0.48wt.%) identical to a later interaction with a melt of island-arc tholeiite (IAT) composition. Meta-basalt from the Beyçam area is the representative of such a melt and displays the whole-rock M-HREE pattern of a complementary product of the Beyçam harzburgite. Data presented in this study support the primarily northward directed closure of the Rheic ocean, but suggest that the Variscan basement in the eastern part of the Sakarya Zone consists of mantle peridotites formed in a south-vergent SSZ. This dual polarity of subduction in the Rheic ocean, at least in the second half of its closure, is also favored by the geological structure and lithological diversity of the Variscan rocks. These are: (1) spatial distribution of the peridotites, e.g., SSZ-type harzburgites to the north and abyssal-type lherzolites to the south, (2) lack of high-pressure metamorphic rocks, (3) decrease in the degree of Variscan metamorphism toward the north, and (4) emplacement of Variscan syn-collisional magmatism into the low grade metamorphic rocks to the north. Paleotethys was the other ocean of the region created in the Late Paleozoic. Northward subduction of the Rheic ocean from Early Devonian to Early Carboniferous appears to be the most plausible mechanism responsible for the opening of Paleotethys. In this scenario the Paleotethys is envisaged as a back-arc basin opened to the north in the wake of separated terranes from Laurussia. Onset of trench-Rheic mid-ocean ridge collision in the Early Devonian along the northern margin of Laurussia has been proposed to account for the initiation of SSZ-type subduction to the south. The short duration of this subduction appears insufficient to open a fully developed back-arc basin to the south because the elimination of Rheic mid-ocean ridge to the north accelerated the oceanic closure.

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  • MakaleAçık Erişim2011
    Frequency optimization of laminated skewed open cylindrical shells

    Topal, Umut; Uzman, Ümit

    This paper deals with frequency optimization of symmetrically laminated skewed open cylindrical shells. The design objective is the maximization of the fundamental frequency and the design variable is the fiber orientations. The firstorder shear deformation theory (FSDT) is used for the finite element solution of the shells. The modified feasible direction (MFD) method is used for the optimization routine. For this purpose, a program based on FORTRAN is used. Finally, the numerical analysis is carried out to investigate the effect of skew angles, length to radius ratios, subtended angle and boundary conditions on, the optimal designs and the results are compared.

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  • MakaleYalnız künye2011
    Calc-alkaline I-type plutons in the eastern Pontides, NE Turkey: U-Pb zircon ages, geochemical and Sr-Nd isotopic compositions

    Kaygusuz, Abdullah; Şen, Cüneyt

    The Köprübaşi{dotless} intrusion from the eastern Pontides of NE Turkey consists of granodiorite and monzogranite, and contains a number of mafic microgranular enclaves (MMEs). We report here U-Pb zircon age, geochemical and Sr-Nd isotopic data for these rocks in order to determining magma sources and magma production processes. On the basis of U-Pb zircon sensitive high-resolution ion microprobe dating (SHRIMP), the magma emplacement age of the granodiorite is 79.3±1.4Ma. The rocks of the pluton are calc-alkaline, metaluminous to peraluminous characteristics, and display features of I-type granites. They are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) with negative Eu anomalies (Eu/Eu*=0.60-0.76), but are depleted in high field strength elements (HFSE). They have small range of 87Sr/86Sr(i) (0.7067-0.7070) and e{open}Nd(i) (-3.2 to -4.4) values. Fractionation of plagioclase, hornblende and Fe-Ti oxides played an important role in the evolution of the Köprübaşi{dotless} intrusion. A relatively shallow intrusion depth (∼2-8km) was estimated from the Al-in-hornblende geobarometry. All these characteristics, combined with the low values of K2O/Na2O, SiO2, Al2O3/(FeOT+MgO+TiO2) and (Na2O+K2O)/(FeOT+MgO+TiO2), suggest an origin by dehydration melting from a metabasaltic lower crustal source.

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  • MakaleYalnız künye2011
    Petrogenesis of a Late Cretaceous composite pluton from the eastern Pontides: The Daǧbasi pluton, NE Turkey

    Kaygusuz, Abdullah; Aydingakir, Emre

    Zircon U-Pb ages, major and trace elements, and Sr-Nd isotope data are reported for the Late Cretaceous Dagbasi pluton from the eastern Pontides, NE Turkey. This pluton has calc-alkaline affinity and displays typical features of volcanic arc granitoids. It is a composite pluton consisting of tonalite, granodiorite, and monzogranite, all containing mafic microgranular enclaves (MMEs). Based on U-Pb zircon SHRIMP dating, magma emplacement ages of the tonalite, granodiorite, and monzogranite are 88.1 ± 1.7 Ma, 86.0 ±2.0 Ma, and 82.9 ± 1.3 Ma, respectively. The tonalites have low SiO2 (60-64 wt%) and display metaluminous to peraluminous characteristics. They have similar Lacn/Lucn (1.5-7.3) and Eu/Eu* (0.65-0.88) values compared to granodiorites and monzogranites. The isotopic signatures of these rocks εNd(i) = -1.4 to -1.7; 87Sr/86Sr(i) = 0.7056-0.7060) are largely similar to granodiorites and monzogranites. Samples from the granodiorites and monzogranites have SiO2 between 69 and 76 wt% and display peraluminous to slightly metaluminous characteristics. Chondrite-normalized REE patterns are characterized by moderate Lacn/Lucn ratios (1.6-7.1), with pronounced negative or positive Eu anomalies (Eu/Eu* = 0.46-1.11). Radiogenic isotope signatures of granodiorites and monzogranites show overlapping 87Sr/86Sr(i), (0.7057-0.7067) and εNd(i) (-3.2 to + 1.5) values. The MMEs have similar geochemical and isotopic features as the host rocks. All plutonic rocks are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE). Fractionation of plagioclase, hornblende, and Fe-Ti oxides played an important role in the evolution of Daǧbasi granitoids. All these geochemical and isotopic characteristics suggest an origin by dehydration melting of an amphibolitic lower crustal source.

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  • MakaleYalnız künye2011
    Modeling and forecasting of Turkey's energy consumption using socio-economic and demographic variables

    Kankal, Murat; Akpinar, Adem; Kömürcü, Murat Ihsan; Özşahin, Talat Şükrü

    This study deals with the modeling of the energy consumption in Turkey in order to forecast future projections based on socio-economic and demographic variables (gross domestic product-GDP, population, import and export amounts, and employment) using artificial neural network (ANN) and regression analyses. For this purpose, four diverse models including different indicators were used in the analyses. As the result of the analyses, this research proposes Model 2 as a suitable ANN model (having four independent variables being GDP, population, the amount of import and export) to efficiently estimate the energy consumption for Turkey. The proposed model predicted the energy consumption better than the regression models and the other three ANN models. Thus, the future energy consumption of Turkey is calculated by means of this model under different scenarios. The predicted forecast results by ANN were compared with the official forecasts. Finally, it was concluded that all the scenarios that were analyzed gave lower estimates of the energy consumption than the MENR projections and these scenarios also showed that the future energy consumption of Turkey would vary between 117.0 and 175.4. Mtoe in 2014.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 13 · İklim Eylemi
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  • MakaleYalnız künye2011
    Dynamic Characteristics of a Prototype Arch Dam

    Sevim, B.; Bayraktar, A.; Altunışık, A.C.; Adanur, S.; Akköse, M.

    This study determines the dynamic characteristics of a prototype arch dam-reservoir-foundation system using Operational Modal Analysis method. Achievement of this purpose involved construction of a prototype arch dam-reservoir-foundation system under laboratory conditions. Ambient vibration tests on the arch dam model identified its natural frequencies, mode shapes, and damping ratios. Natural excitations such as small impact loads vibrated to arch dam. Sensitivity accelerometers which were placed on the dam's crest collected signals in measurements. Measurements were recorded for empty and full reservoirs. Operational Modal Analysis software processed signals which were collected from the ambient vibration tests. Enhanced Frequency Domain Decomposition technique estimated dynamic characteristics of the dam. Results showed that there was an approximate 20-25% difference between natural frequencies related to empty and full reservoirs.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
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  • MakaleYalnız künye2011
    Preconcentration of Cd(II) and Cu(II) ions by coprecipitation without any carrier element in some food and water samples

    Duran, Celal; Ozdes, Duygu; Sahin, Deniz; Bulut, Volkan Numan; Gundogdu, Ali; Soylak, Mustafa

    A simple, rapid, sensitive and environmentally friendly separation and preconcentration procedure, based on the carrier element free coprecipitation (CEFC) of Cu(II) and Cd(II) ions by using an organic coprecipitant, 2-{[4-(4-fluorophenyl)-5-sulphanyl-4H-1,2,4-triazol-3-yl]methyl}-4-{[(4-fluorophenyl) methylene]amino}-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (MEFMAT) was developed. The analyte ions were determined by flame atomic absorption spectrometric (FAAS) determinations. The optimum conditions for the coprecipitation process were investigated on several commonly tested experimental parameters such as pH of the solution, amount of MEFMAT, sample volume, standing time, centrifugation rate and time. The influences of some anions, cations and transition metals on the recoveries of analyte ions were also investigated, and no considerable interference was observed. The preconcentration factor was found to be 50. The detection limits for Cu(II) and Cd(II) ions based on the three times the standard deviation of the blanks (N:10) were found to be 1.49 and 0.45μgL-1, respectively. The relative standard deviations were found to be lower than 3.5% for both analyte ions. The method was validated by analyzing two certified reference materials (CRM-TMDW-500 Drinking Water and CRM-SA-C Sandy Soil C) and spike tests. The procedure was successfully applied to sea water and stream water as liquid samples and tobacco, hazelnut and black tea as solid samples.

    • SDG 6 · Temiz Su ve Sanitasyon
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  • MakaleAçık Erişim2011
    Modelling 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.

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  • MakaleAçık Erişim2011
    Mild 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.

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  • MakaleYalnız künye2011
    Laparoscopic 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.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
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  • MakaleAçık Erişim2011
    Nonlinear 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.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    • SDG 11 · Sürdürülebilir Şehirler ve Topluluklar
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