Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(77)
- Merdan, Mehmet(73)
- Duran, Celal(54)
- Ozdes, Duygu(50)
- Baltaci, Cemalettin(45)
- Kaygusuz, Abdullah(45)
- Kulakaç, Nurşen(39)
- Ashyralyyev, Charyyar(38)
- Karsli, Orhan(37)
- Demir, Selim(36)
- Öztürk, Serkan(36)
- Dokuz, Abdurrahman(35)
- Turan, Ibrahim(35)
- Araz, Onur(33)
- Kandemir, Raif(31)
- Sipahi, Ferkan(30)
- Topal, Fevzi(30)
- Kurt, Kemal(28)
- Peker, Iskender(28)
- Arslan, Mehmet(27)
- Baltacı, Cemalettin(27)
- Maden, Nafiz(27)
- Ozturk, Samet(27)
- Aydin, Aydanur(26)
- Vural, Alaaddin(26)
- Bayrakdaroglu, Serdar(25)
- Kurnaz, Muammer(25)
- Reis, Hatice Catal(25)
- Akar, Zeynep(24)
- Aydin, Faruk(24)
- Gücer, Mehmet Ali(24)
- Topal, Meryem(24)
- Yolcu, Halil(24)
- Yücel, Cem(24)
- Anaç, Halil(23)
- Kankal, Murat(23)
- Ürkek, Bayram(23)
- Aliyazicioglu, Yuksel(22)
- Günen, Mehmet Akif(22)
- Tuncer, Metin(22)
Yayınlar
- MakaleYalnız künye2011Scopus SJRQ2Mild and severe anal incontinence after lateral internal sphincterotomy: Risk factors, postoperative anatomical findings and quality of life
Kement, M.; Karabulut, M.; Gezen, F.C.; Demirbas, S.; Vural, S.; Oncel, M.
Aim: This study aims to evaluate the risk factors for incontinence after lateral internal sphincterotomy (LIS) and assess quality of life in different levels of incontinence. Methods: All consecutive patients (n = 253) with chronic anal fissure who underwent LIS between 2003 and 2006 were retrospectively reviewed. All patients were questioned for possible anal incontinence according to the Wexner Incontinence Score (WIS). Demographics, vaginal delivery history, additional procedures and surgeon's experience were evaluated as risk factors. Endoanal ultrasound (EUS) was performed in incontinent patients to assess the thickness of the remaining internal sphincter and to evaluate any injury in the external sphincter. Quality of life was questioned with SF-36. Results: Twenty-eight (11.7%) patients suffered from incontinence (mean WIS = 3.6 ± 2.5). The search for a risk factor was unsuccessful when continent and incontinent groups were compared. In subgroup analyses, patients were found to be suffering from mild (WIS <5, n = 19) or severe (WIS >5, n = 9) incontinence. Vaginal delivery history was found more often in the severely incontinent subgroup than in the continent group (p < 0.05). Also, vaginal delivery history and the additional procedures were more frequently observed in the severely incontinent subgroup than in the mildly incontinent subgroup. EUS did not find any external sphincter injury in these cases. WIS had negative correlations with the physical and mental component scores of SF-36. Conclusion: In our opinion, the threat for incontinence is unpredictable; however, vaginal delivery history may increase the risk of severe incontinence.
AtıfScopus14WoS13OpenAlex17İncele - MakaleYalnız künye2011Scopus SJRQ2Finite element model calibration of berke arch dam using operational modal testing
Sevim, Bariş; Bayraktar, Alemdar; Altunişik, Ahmet Can
This paper presents the finite element calibration of Berke Arch Dam by using Operational Modal Testing. Achievement of this purpose involves structural vibration characteristics of Berke Arch Dam using analytical and Operational Modal Analyses. Therefore, the study has two parts-analytical and experimental. In the analytical part of the study, the authors developed a 3D finite element model of Berke Arch Dam-reservoir-foundation system using ANSYS software, and analytically determined vibration characteristics such as natural frequencies and mode shapes. In the experimental part of the study, sensitive accelerometers were placed to several points of Berke Arch Dam, and ambient vibration tests were conducted over four days to obtain dynamic characteristics. The Enhanced Frequency Domain Decomposition technique is used to estimate natural frequencies, mode shapes and damping ratios of the Berke Arch Dam experimentally. Results showed that there were some differences between analytical and experimental natural frequencies of the dam. Therefore, an analytical model of Berke Arch Dam was calibrated to minimize these differences by changing material properties. Analytical results obtained from the calibrated model mainly conform to those of the experimental model.
AtıfScopus53WoS43OpenAlex44İncele - MakaleYalnız künye2011Scopus SJRQ2Solid waste management practices in Turkey
Berkun, Mehmet; Aras, Egemen; Anılan, Tugce
As an economically developing country, Turkey has very well operated integrated solid waste management applications structured on modern facilities, besides over 2,000 scattered open dump areas in the country. Integrated waste management applications seem eligible for the metropolitan cities like Istanbul and Izmit (Kocaeli). Attempts have not been encouraging for the scattered regional settlements using central storage sites due to financial shortages and received rejections from nearby settlements. Small-scale compact solid waste management systems with materials recycling and composting can be more suitable alternatives in the small-scale regional settlements. The major constituents of municipal solid waste are organic in nature and approximately a quarter of municipal solid waste is recyclable. Although paper, including cardboard, is the main constituent, the composition of recyclable waste varies strongly by the source or the type of collection point. Solid wastes need primary treatment in order to be suitable for incineration and composting. Turkey needs to give more emphasis on the usage of modern solid waste removal technologies to overcome the overgrowing solid waste disposal problems.
AtıfScopus25WoS18OpenAlex33İncele - BildiriYalnız künye2011Scopus SJRQ1Hydroxyapatite production on ultrafine-grained pure titanium by micro-arc oxidation and hydrothermal treatment
Alsaran, A.; Purcek, G.; Hacisalihoglu, I.; Vangolu, Y.; Bayrak, O.; Karaman, I.; Celik, A.
In this study, pure-Ti (Grade-2) was severely plastically deformed by equal-channel angular extrusion (ECAE) to improve its strength, and then subjected to micro arc oxidation (MAO) and hydrothermal treatment (HT) to achieve improved surface behavior with hydroxyapatite (HA)-containing titania (TiO(2)) coating. Microstructure, tensile properties and wear behavior of UFG Ti were investigated systematically before and after surface modification. ECAE considerably enhanced the strength of coarse-grained (CG) Ti by forming an ultra-fine grained (UFG) microstructure with high dislocation density. The application of MAO with or without HT did not cause remarkable decrease in strength and ductility of CG and UFG Ti, but resulted in a considerable increase in its wear resistance and osseointegration due to the formation of hard and adhered HA-containing TiO2 coating on the surface. It can be concluded that the use of ECAE plus MAO/HA coating provides a simple and effective procedure to obtain pure Ti with high strength and high wear resistance. The improved bulk and surface properties can make this biocompatible material a good potential candidate for biomedical applications instead of alloys including toxic elements. (C) 2011 Elsevier B.V. All rights reserved.
AtıfScopus61WoS61OpenAlex65İncele - MakaleAçık Erişim2011Scopus SJRQ1Transition from shoshonitic to adakitic magmatism in the eastern Pontides, NE Turkey: Implications for slab window melting
Eyuboglu, Yener; Chung, Sun-Lin; Santosh, M.; Dudas, Francis O.; Akaryali, Enver
The formation of the eastern Pontides orogenic belt has been widely assigned to a northward subduction of the Neotethyan oceanic slab during the late Mesozoic-Cenozoic. Here we provide an alternate model based on new geological, geochemical and isotopic data. The magmatic activity in the far south of the belt started in the early Campanian with shoshonitic trachyandesites and associated pyroclastics. This sequence is covered by the late Campanian-early Maastrichtian reefal limestones and another stage of high-K volcanism represented by analcimized leucite-rich ultrapotassic rocks of the Maastrichtian-early Paleocene (?) ages. The shoshonitic and ultrapotassic rocks, with K2O contents ranging from 0.26 to 6.95 wt.%, display broadly similar rare earth and multi-element distribution patterns. Both rock types are enriched in LILE and LREE and depleted in HFSE (Nb,Ta and Ti), suggesting a subduction-enriched mantle source for the magma generation. Subsequently, during the late Paleocene, a stage of acidic magmatism (SiO2 of 53.25-73.61 wt.%) that shows adakitic geochemical characteristics including high Sr/Y (46-416) and La/Yb (11-51) and low Y (2.6-12.2 ppm), is documented characterized by melting of a mafic source such as the MORB crust with garnet in the residue. The adakitic magmatism began at similar to 56 Ma and migrated toward the north through time, culminating with porphyritic andesites (similar to 47 Ma) that were emplaced in the Gumushane-Bayburt line and its vicinity. North of this line, coeval magmas show typical calc-alkaline nature and continued to develop toward further north until the middle to late Eocene. Based on the spatial and temporal variations in the magmas generated in the eastern Pontides orogenic belt, we propose a new geodynamic model to explain the tectonomagmatic evolution of these rocks and correlate the adakitic magmatism to ridge subduction and slab window process within a south-dipping subduction zone. Our model is in contrast to the previous proposals which envisage partial melting or delamination of thickened lower continental crust due to the collision in the south during the Paleocene-Eocene. (C) 2010 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
AtıfScopus172WoS166OpenAlex176İncele - MakaleYalnız künye2011Scopus SJRQ1Adakite-like granitoid porphyries in the Eastern Pontides, NE Turkey: Potential parental melts and geodynamic implications
Karsli, Orhan; Ketenci, Murat; Uysal, Ibrahim; Dokuz, Abdurrahman; Aydin, Faruk; Chen, Bin; Kandemir, Raif; Wijbrans, Jan
The tectonic setting of the Eastern Pontides during the late Mesozoic to early Cenozoic remains a subject of debate. Petrogenesis of adakite-like granitoid porphyries plays a critical role in determining the nature of the lower continental crust and mantle dynamics during orogenic processes in the region. Here we describe, for the first time, the late Paleocene to early Eocene adakite-like granitoid porphyries from the northern part of the Eastern Pontides although their counterparts in the southern part have recently been found. The adakitic porphyries, which emplaced into the subduction-related Turonian-Santonian volcanics from northern part of the region, consist of I-type calc-alkaline quartz monzonite-tonalite (SiO2 = 62.89-65.07 wt.%) and high-k calc-alkaline granodiorite-granite associations (SiO2 = 69.06-70.43 wt.%). The former displays peraluminous to metaluminous signatures, whereas the latter shows peraluminous geochemical character. The granite-granodiorite porphyries have high K2O (3.32-3.84 wt.%), and low Na2O (3.48-4.61 wt.%) and MgO (0.91-1.04 wt.%) relative to the quartz monzonite-tonalite association (K2O = 1.50-1.92 wt.%; Na2O = 4.08-6.45 wt.%; MgO = 1.44-2.07 wt.%). Ar-Ar geochronology studies on the amphibole separates reveal that the adakite-like porphyries have a crystallization ages of 51.34 +/- 0.27 to 53.55 +/- 0.34 Ma. Here, we contend that these rocks were formed by partial fusion of a mafic lower continental crust in a collisional phase but not in a subduction setting. All the samples exhibit the typical geochemical characteristics of adakite, that is, high Sr (250-1141 ppm), high Sr/Y ratios (16-147), low Y (6.8-14.8 ppm) and low HREE concentrations; they are similar to adakites formed by slab melting associated with the subduction zone. However, the rocks exhibit heterogeneity in isotopic composition, with I-Sr ranging from 0.70554 to 0.70986, epsilon(Nd) (51 Ma) from -8.5 to -0.9 and Nd model ages from 0.72 to 1.26 Ga. The samples are characterized by relatively high Th, Th/U and no significant Eu anomalies, implying that garnet was stable in their source during partial melting. The compositional diversity between rock groups is probably related to partial melting of heterogeneous lower crustal source. All of the features are inconsistent with a slab-melting origin and slab-related petrogenetic model, but instead, they favor an origin by melting of heterogeneous lower continental crust due to a thermal anomaly that was induced by the upwelling of the asthenosphere through a slab break-off in a collisional setting. These interpretations argue against the evidence for the presence of an early Cenozoic arc setting in the Eastern Pontides. Instead, the early Cenozoic time in the region may be attributed to a geodynamic response to a post-collisional uplift phase that occurred along the continent-continent collision between the Pontide and the Anatolide-Tauride blocks. (C) 2011 Elsevier B.V. All rights reserved.
AtıfWoS123OpenAlex120İncele - MakaleYalnız künye2011Scopus SJRQ1Migrating magmatism in a continental arc: Geodynamics of the Eastern Mediterranean revisited
Eyuboglu, Yener; Santosh, M.; Dudas, Francis O.; Chung, Sun-Lin; Akaryali, Enver
The eastern Pontide orogenic belt in Turkey offers a critical region to evaluate the geodynamic evolution of the eastern Mediterranean region during the late Mesozoic-Cenozoic. Here we synthesize results from our exhaustive database on the geochemical characteristics of adakitic magmatism from 137 bodies covering 7 domains in the southern zone of eastern Pontides. Together with new Pb-Sr-Nd results, we show that the adakitic magmatism in the eastern Pontide belt is clearly linked to slab window processes during ridge subduction, as against the earlier models that assumed partial melting of a delaminated or thickened lower continental crust following collision. The isotopic compositions display a complex pattern and suggest mixing of multiple source materials such as depleted mantle, enriched lithospheric mantle, and upper crust. We also confirm a southward polarity of subduction as against the previous models that assumed a northward subduction. We supplement our model with evidence for a northward propagation of the adakitic magmatism, spatial and temporal variations in arc magmatism, presence of south-dipping reverse faults and a synthesis of the available paleomagnetic data. Our studies also suggest that the Black-Sea is a remnant of the Tethyan ocean that was situated to the north of the arc during the late Mesozoic-Cenozoic as against the correlation to a late Mesozoic-Cenozoic back-arc basin related to a northward subduction of the Paleo- or Neo-tethyan oceanic lithosphere in alternate models. (C) 2010 Elsevier Ltd. All rights reserved.
AtıfScopus58WoS52OpenAlex56İncele - MakaleYalnız künye2010Homotopy perturbation method for solving a three-species food chain model
Merdan, Mehmet
In this article, homotopy perturbation method is implemented to give approximate and analytical solutions of nonlinear ordinary differential equa tion systems such as a three-species food chain model. The proposed scheme is based on homotopy perturbation method (HPM), Laplace transform and Padé approximants. Some plots are presented to show the reliability and simplicity of the methods.
- MakaleYalnız künye2010A new application of modified differential transformation method for modelling the pollution of a system of lakes
Merdan, Mehmet
In this papers, a new application of modified differential transformation method (MDTM) is implemented to solve analytically systems of nonlinear ordinary differential equations such as modelling the pollution of a system of lakes. The proposed scheme is based on differential transformation method (DTM), Laplace transform and Padé approximants. The results to get the differential transformation method (DTM) are applied Padé approximants. Our proposed approach showed results to analytical solutions of nonlinear ordinary differential equation systems. The results are compared with the results obtained by MATLAB ode23s and the differential transformation method (DTM) are applied Padé approximants. At the end, these solutions are illustrated by tables and figures.
AtıfTR Dizin7İncele - MakaleAçık Erişim2010Scopus SJRQ2Combination technique of tumescent anesthesia during endovenous laser therapy of saphenous vein insufficiency
Memetoglu, Mehmet Erdem; Kurtcan, Serpil; Kalkan, Asim; Özel, Deniz
Objective: This study aimed at evaluating the efficiency of applying tumescent anesthesia before an ablation procedure and continuously during endovenous laser treatment (EVLT) (combined tumescent technique) of saphenous vein insufficiency to reduce the patients pain and discomfort. Methods: Twenty-five patients with 31 duplex-confirmed great saphenous vein insufficiency underwent endovenous laser (940 nm) varicose vein treatment between December 2009 and April 2010. The patients were randomized in two groups. In group A (15 patients) tumescent anesthesia was used before the ablation procedure and in group B (10 patients) tumescent anesthesia was used before and continuously during the procedure. Patients were scheduled for a three-day examination after EVLT to assess the level of pain experienced. Results: According to the statistic analysis we observed that the mean level of pain score for the patients given classical tumescent anesthesia showed a higher level (P=0.003) compared with the patients given tumescent anesthesia in the combined procedure. Conclusion: Combination technique of administering tumescent anesthesia before ablation and continuously during the EVLT procedure may be an alternative way to reduce the patient's peroperative pain and discomfort. (C) 2010 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.
AtıfWoS17OpenAlex28İncele - MakaleAçık Erişim2010The Relationship Between Knee Osteoarthritis and Osteoporosis
Sezer, Ilhan; Illeez, Ozge G.; Tuna, Serpil D.; Balci, Nilufer
Objective: The aim of this study was to investigate the association between knee osteoarthritis (OA) and bone mineral density (BMD) in the femur and lumbar vertebrae. Materials and Methods: A total of 74 female patients (mean age 61.9 +/- 9.1 years, mean body mass index 27.09 +/- 4.24) diagnosed with knee OA were included in this study. To assess knee OA, bilateral weight-bearing antero-posterior knee radiographs were taken and graded from 0 to 4 according to Kellgren-Lawrence criteria. The BMD of the subjects was measured using dual-energy X-ray absorptiometry (DEXA). BMD measurements of those with OA were compared with those without OA. Results: While there was no correlation between BMD and the grade of knee OA, a significant negative correlation was found between age and femur BMD. Body mass index was positively correlated with OA and negatively correlated with OP. Conclusion: Further investigations are needed to demonstrate the association between knee OA and BMD.
AtıfWoS9OpenAlex14İncele - MakaleAçık Erişim201017,18-Dibromo-8-methyl-4,12-ditosyl-3,4,5,6,7,8,9,10,11,12,13,14-dodecahydro-2H-benzo[b][1,4,7,11,15]dioxatriazacycloheptadecine
Kelesoglu, Zeynep; Kaya, Elif Celenk; Kantekin, Halit; Bueyuekguengoer, Orhan
In the title compound, C31H39Br2N3O6S2, a 17-membered aza-macrocyclic ligand containing two ether O and three aza N atoms, the three pendant aromatic rings form an 'E' shape. The dihedral angles between the central benzene ring and the side ones are 17.8 (3) and 7.4 (3)degrees , and the dihedral angle between the tosyl rings is 10.6 (3)degrees . The methyl group is disordered over two orientations, with occupancies of 0.52 (15) and 0.48 (15).
AtıfOpenAlex1İncele - MakaleYalnız künye2010Scopus SJRQ1The synthesis and characterization of metal-free and metallophthalocyanine polymers by microwave irradiation containing diazadithia macrocyclic moieties
Kaya, Elif Celenk; Karadeniz, Huelya; Kantekin, Halit
A tetranitrile monomer was synthesized by nucleophilic aromatic substitution of N,N'-(2,2'-(propane-1,3-diylbis(sulfanediyl))bis(ethane-2,1-diyl))bis(4-methylbenzenesulfonamide) onto 4-nitrophthalonitrile. A metal-free phthalocyanine polymer was prepared by the reaction of the tetranitrile monomer under N-2 in the presence of 2-(dimethylamino)ethanol at 145 degrees C for 24 h. Zinc(II), copper(II), cobalt(II), nickel(II), lead (II), phthalocyanine polymers were prepared by reaction of the tetranitrile with the chlorides of zinc (II), copper (II), cobalt (II), nickel (II), lead (II), employing microwave irradiation in the presence 2-(dimethylamino)ethanol at 175 degrees C, 350 W for 10 min. The thermal stabilities of the phthalocyanine compounds were determined by thermogravimetric analysis. The new compounds were characterized by a combination of IR, H-1 NMR, C-13 NMR, UV-vis, elemental analysis and MS spectral data. (C) 2009 Elsevier Ltd. All rights reserved.
AtıfWoS9OpenAlex10İncele - MakaleYalnız künye2010Scopus SJRQ3Liquefaction of cotton stalks (Gossypium hirsutuml.) with phenol
Fidan, M.Said; Alma, M.Hakki; Bektas, Ibrahim
In this study, we aimed to synthesize resol type wood adhesive from resinification of cotton stalk liquefied into phenol in the presence of sulfuric acid as catalyst. The biomass was first liquefied with phenol in the presence of sulfuric acid as a catalyst at various reaction conditions. It was detected that increasing acid concentration, temperature and time resulted in a great decrease on the amount of unliquefied cotton stalks and a significant increase in the percentage of combined phenol in the produced resin. It was also found out that the resin produced from cotton stalks can be perfectly used in the production of wood composite materials.
AtıfScopus9WoS7İncele - MakaleAçık Erişim2010Scopus SJRQ1Structure and geochemistry of an Alaskan-type ultramafic-mafic complex in the Eastern Pontides, NE Turkey
Eyuboglu, Yener; Dilek, Yildirim; Bozkurt, Erdin; Bektas, Osman; Rojay, Bora; Sen, Cuneyt
The Karayasmak ultramafic-mafic association (KUMA) in NE Turkey represents an Alaskan-type, pre-Liassic intrusion in the Pulur metamorphic massif and is one of many such intrusive complexes that were emplaced into the continental basement of the Eastern Pontides belt during the pre-Liassic. Its main lithological units include plagioclase peridotite, melagabbronorite, banded gabbro and anorthosite (Phase-I), gabbro-pegmatite dikes (Phase-II), unmetamorphosed banded gabbro (Phase-III), cumulate olivine gabbronorite (Phase-IV), and non-cumulate gabbroic dikes and stocks (Phase-V). The contact relations between these units are gradational or intrusive, with the peridotites (Phase-I) enveloping the cumulate gabbronorites (Phase-IV) in the center of the elliptical body, displaying a concentric reverse-zoning pattern. Cr-Al spinel, plagioclase, and olivine are the first crystallizing phases in all cumulate rocks, whereas pyroxene, hornblende, phlogopite, magnetite, and ilmenite represent the intercumulus phases. The existence of hornblende and phlogopite, the high Wo and Cr2O3 contents of clinopyroxene, and the high Fo and NiO contents of olivine indicate that the KUMA units were the near-liquidus fractional crystallization products of hydrous basaltic magma. The Phase-I and Phase-III cumulates are slightly enriched in LILE and LREE, depleted in HFSE and HREE with respect to chondrite and primitive mantle, and show negative Nb, Zr, Hf and Ti anomalies. The Phase-IV cumulate gabbronorites are even more enriched in LILE and LREE and show less depletion in HFSE and HREE in comparison to the earlier phases. The KUMA units formed from high-Al hydrous basaltic magmas, which were derived from partial melting of a previously subduction-metasomatized subcontinental-lithospheric mantle. These magmas underwent crystal fractionation and mineral concentration processes in small magma chamber(s) at shallow crustal levels (< 5 kbar).
AtıfScopus123WoS115OpenAlex112İncele - MakaleYalnız künye2010Scopus SJRQ3Consumer perceptions of organic foods in Turkey
Ilyasoǧlu, Huri; Temel, Sara; Özçelik, Beraat
This study presents the results of a survey regarding consumer perceptions of organic foods in Turkey. The survey was conducted to determine consumer attitudes towards organic foods and the reasons for consumption or non-consumption of organic foods. A total of 383 consumers from different occupational groups living in Istanbul participated in the research. The results of the survey revealed that more than half of the survey participants had knowledge about organic foods. The majority of the participants were positive towards organic foods and purchased them as well. The results of chi-square analysis showed that the consumption of organic foods varied with respect to gender, job and education. Women and more educated participants tend to buy organic foods more than other participants. In market, fruits and vegetables, cereals and legumes, dried fruits and dairy products were organic products recognized by consumers. The main organic products purchased by consumers were fruits and vegetables. The results of the survey also indicated that the participants confidence in organic foods was at moderate level. About 37% of the participants was found to rely on organic foods and about 49% of the participants were unsure about organic foods. Organic foods were purchased because they were perceived as healthy, environmentally friendly and more nutritious than conventional foods. However, the consumption of organic foods was found to be lower. The majority of the participants stated that they consumed organic foods rarely or sometimes. Price and lack of availability of organic foods were barriers to increase the consumption of organic foods.
AtıfScopus4WoS2İncele - MakaleYalnız künye2010Scopus SJRQ1Generation of the Early Cenozoic adakitic volcanism by partial melting of mafic lower crust, Eastern Turkey: Implications for crustal thickening to delamination
Karsli, Orhan; Dokuz, Abdurrahman; Uysal, Ibrahim; Aydin, Faruk; Kandemir, Raif; Wijbrans, Jan
Early Cenozoic (48-50 Ma) adakitic volcanic rocks from the Eastern Pontides, NE Turkey, consist of calc-alkaline and high-K calc-alkaline andesite and dacite, with SiO2 contents ranging from 56.01 to 65.44 wt.%. This is the first time that Early Eocene volcanism and adakites have been reported from the region. The rocks are composed of plagioclase, amphibole, quartz, and Mg-rich biotite. They have high and low-Mg# values ranging from 55 to 62 and 13 to 42, respectively. High-Mg# rocks have higher Ni and Co contents than low-Mg# samples. The rocks exhibit enrichments in large ion lithophile elements including the light rare earth elements, depletions in Nb, Ta and Ti and have high La/Yb and Sr/Y ratios. Their relative high ISr (0.70474-0.70640) and low εNd (50 Ma) values (- 2.3 to 0.8) are inconsistent with an origin as partial melts of a subducted oceanic slab. Combined major- and trace element and Sr-Nd isotope data suggest that the adakitic magmas are related to the unique tectonic setting of this region, where a transition from a collision to an extension stage has created thickening and delamination of the Pontide mafic lower crust at 50 Ma. The high-Mg adakitic magmas resulted from partial melting of the delaminated eclogitic mafic lower crust that sank into the relatively hot subcrustal mantle, and its subsequent interaction with the mantle peridotite during upward transport, leaving garnet as the residual phase, elevates the MgO content and Mg# of the magmas, whereas low-Mg# magmas formed by the melting of newly exposed lower crustal rocks caused by asthenospheric upwelling, which supplies heat flux to the lower crust. The data also suggest that the mafic lower continental crust beneath the region was thickened between the Late Cretaceous and the Late Paleocene and delaminated during Late Paleocene to Early Eocene time, which coincides with the initial stage of crustal thinning caused by crustal extensional events in the Eastern Pontides and rules out the possibility of an extensional regime before ~ 50 Ma in the region during the Late Mesozoic to Early Cenozoic.
AtıfScopus257WoS238OpenAlex247İncele - MakaleYalnız künye2010Scopus SJRQ1Prognostic significance of perineural invasion in patients with gastric cancer who underwent curative resection
Bilici, Ahmet; Seker, Mesut; Ustaalioglu, Bala Basak Oven; Kefeli, Umut; Yildirim, Emre; Yavuzer, Dilek; Aydin, Fatih Muhammed; Salepci, Taflan; Oncel, Mustafa; Gumus, Mahmut
Background: The prognostic significance of perineural invasion (PNI) in gastric cancer has been previously investigated in a few studies, but had not reached a consensus. The aim of this study was to determine the prognostic value of PNI in patients with gastric cancer who underwent curative resection. Materials and Methods: We retrospectively analyzed 238 patients who had undergone curative gastrectomy. Paraffin sections of surgical specimens from all patients were stained with hematoxylin and eosin. PNI was defined when carcinoma cells infiltrated into the perineurium or neural fascicles. PNI and the other prognostic factors were evaluated by univariate and multivariate analysis. Results: PNI was detected as positive in 180 of the 238 patients (75.6%). pT stage, tumor size, lymph node metastasis, clinical stage, tumor differentiation, Borrmann classification, histological type, lymphatic vessel invasion, and blood vessel invasion were closely associated with the presence of PNI. The PNI-positive tumors had significantly larger size and more lymph node metastasis than the PNI-negative tumors (P =.001 and P <.001, respectively). The median survival of the PNI-positive patients was significantly worse than that of the PNI-negative patients (28.1 vs. 64.9 months, P =.001). Multivariate analysis indicated that the positivity of PNI was an independent prognostic factor (P =.02, hazard ratio [HR]: 2.75; 95% confidence interval [95% CI]:1.12-3.13) as were classical clinicopathological features. Conclusion: Our results showed that the frequency of PNI was high in patients with gastric cancer who underwent curative gastrectomy and the proportion of PNI positivity increased with progression and clinical stage of disease. PNI may be useful in detecting patients who had poor prognosis after curative resection in gastric cancer.
AtıfScopus101WoS98OpenAlex108İncele - MakaleYalnız künye2010Scopus SJRQ3Responses of some wheat genotypes and their F2 progenies to salinity and heat stress
Yildirim, Mehmet; Bahar, Bilge
Both heat and salinity cause yield decrease in wheat. Grain yield in wheat has increased as a result of breeding efforts for different stress conditions. However, there are still substantial opportunities to improve grain yield by using conventional breeding under stress conditions, like heat and salt stress. The objective of this study was to investigate heat and salt effects on yield and some agronomic traits of four wheat genotypes and their six half F2 diallel cross progenies grown in pots. Significant differences were found among the genotypes for grain yield under both heat stress and non-stress condition. There was a mean reduction in yield of 12.6% due to salt stress. The reduction in biomass was higher than grain yield under salt stress while it was lower at heat stress. Grain yield was positively correlated with spike weight, harvest index, grain numbers per plant and biological yield under non stress (NS), heat stress (HS) and salt stress (SS) conditions. Cultivars Seri 82 and Chil's had high yield among parents under both NS and SS. Chil's and its hybrids showed low reduction in yield due to SS; thus, exhibiting salt tolerance. Also, Chil's was found to be good combiner with high General Combining Ability (GCA) effects for grain yield under SS conditions. 84 CZT04 was the most susceptible cultivar under SS. Significant GCA effects of Genç 99 and 84CZT04 provided positive contribution to grain yield under HS. It was impossible to select both heat and salt tolerant genotype with high yield capacity from the used genotypes. However, heat or salt tolerant genotypes can be improved by selection breeding due to genetic variation among genotypes.
AtıfScopus9WoS7İncele - MakaleYalnız künye2010Scopus SJRQ1Late Cretaceous high-K volcanism in the eastern Pontide orogenic belt: Implications for the geodynamic evolution of NE Turkey
Eyüboǧlu, Yener
High-K volcanics were produced in two different Late Cretaceous cycles during the infilling of back-arc basins of the eastern Pontides. The first cycle, represented by shoshonitic trachyandesites and associated pyroclastics, containing high K2O (2.74-4.81 wt-%) and NaK2O (3.60-5.51 wt-%), overlies a mid-Cretaceous ophiolitic-olistostromal melange formed during the rifting stage of a back-arc basin (Neotethys). 40Ar39Ar dating of biotite from trachyandesite at the base of the first cyle indicates that shoshonitic volcanism in the far south of the eastern Pontides started in the early Campanian. Volcanic rocks of this cycle are overlain by upper Campanian-Maastrichtian rudist-bearing reefal limestones. The second cycle of high-K volcanism is represented by analcime-bearing volcanic rocks erupted in a Neotethyan lagoonal environment. These volcanic rocks, intercalated with continental detritus, are characterized by high a2O (3.22-7.16 wt-%), now concentrated in secondary analcime crystals. Their K2O contents also range between 0.83 and 6.05 (wt-%). All of these units are disconformably overlain by Eocene turbidites with a basal conglomerate. Volcanic rocks belonging to both cycles show various enrichment degrees in LILE, HFSE, LREE, and HREE with respect to primitive mantle and chondrite [(La/Lu) cn=11.10-25.89]. Negative Nb, Ta, Zr, Hf, and Ti anomalies are typical of these subduction-related arc magmas. Geochemical similarities between the two volcanic cycles suggest that trachyandesites and analcime-bearing volcanics were derived from similar enriched mantle sources, and that they formed in the same geotectonic setting of a back-arc basin environment of the eastern Pontide magmatic arc during the Late Cretaceous. In addition, Nd-Sr and Pb isotope ratios of the investigated volcanic units indicate that their mantle melt sources were similar. The new geological, geochemical and isotopic data suggest that southward subduction of the Palaeotethyan oceanic crust can be separated into two main stages for the late Mesozoic Pontide orogenic belt. Early southward subduction ended by slab break-off during the mid-Cretaceous, resulting in upwelling and injection of asthenospheric mantle that caused the opening of the eastern Pontide back-arc basin (Neotethys). Resumption of southward subduction began with intense TH-CA bimodal volcanism in the northern front of the arc during the Turonian-Coniacian. The intensity of this Late Cretaceous magmatism in the north decreased towards the south, and a transition to monogenic calcalkaline-alkaline (CA-A) Campanian andesitic volcanism developed in the southern zone. Yet farther south, andesitic igneous activity graded into the Campanian-Maastrichtian shoshonitic and ultrapotassic volcanism in the Bayburt-Maden, Tokat, Amasya, and Gümüshaciköy areas. This zoning of the Late Cretaceous arc magmatism (TH-CA, CA-A and shoshonitic-ultrapotassic, from north to south) also supports the concept of southward subduction during late Mesozoic evolution of the eastern Mediterranean region.
AtıfScopus120WoS110OpenAlex117İncele