640 research outputs found

    İzmir‐Ankara suture as a Triassic to Cretaceous plate boundary – data from central Anatolia

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    The İzmir‐Ankara suture represents part of the boundary between Laurasia and Gondwana along which a wide Tethyan ocean was subducted. In northwest Turkey, it is associated with distinct oceanic subduction‐accretion complexes of Late Triassic, Jurassic and Late Cretaceous ages. The Late Triassic and Jurassic accretion complexes consist predominantly of basalt with lesser amounts of shale, limestone, chert, Permian (274 Ma zircon U‐Pb age) metagabbro and serpentinite, which have undergone greenschist facies metamorphism. Ar‐Ar muscovite ages from the phyllites range from 210 Ma down to 145 Ma with a broad southward younging. The Late Cretaceous subduction‐accretion complex, the ophiolitic mélange, consists of basalt, radiolarian chert, shale and minor amounts of recrystallized limestone, serpentinite and greywacke, showing various degrees of blueschist facies metamorphism and penetrative deformation. Ar‐Ar phengite ages from two blueschist metabasites are ca. 80 Ma (Campanian). The ophiolitic mélange includes large Jurassic peridotite‐gabbro bodies with plagiogranites with ca. 180 Ma U‐Pb zircon ages. Geochronological and geological data show that Permian to Cretaceous oceanic lithosphere was subducted north under the Pontides from the Late Triassic to the Late Cretaceous. This period was characterized generally by subduction‐accretion, except in the Early Cretaceous, when subduction‐erosion took place. In the Sakarya segment all the subduction accretion complexes, as well as the adjacent continental sequences, are unconformably overlain by Lower Eocene red beds. This, along with the stratigraphy of the Sakarya Zone indicate that the hard collision between the Sakarya Zone and the Anatolide‐Tauride Block took place in Paleocene

    Magnetic Resonance Study of Fe-Implanted TiO<inf>2</inf> Rutile

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    © 2017, Springer-Verlag Wien.Single-crystal (100) and (001) TiO2 rutile substrates have been implanted with 40 keV Fe+ at room temperature with high doses in the range of (0.5–1.5) × 1017 ions/cm2. A ferromagnetic resonance (FMR) signal has been observed for all samples with the intensity and the out-of-plane anisotropy increasing with the implantation dose. The FMR signal has been related to the formation of a percolated metal layer consisting of close-packed iron nanoparticles in the implanted region of TiO2 substrate. Electron spin resonance (ESR) signal of paramagnetic Fe3+ ions substituting Ti4+ positions in the TiO2 rutile structure has been also observed. The dependences of FMR resonance fields on the DC magnetic field orientation reveal a strong in-plane anisotropy for both (100) and (001) substrate planes. An origin of the in-plane anisotropy of FMR signal is attributed to the textured growth of the iron nanoparticles. As result of the nanoparticle growth aligned with respect to the structure of the rutile host, the in-plane magnetic anisotropy of the samples reflects the symmetry of the crystal structure of the TiO2 substrates. Crystallographic directions of the preferential growth of iron nanoparticles have been determined by computer modeling of anisotropic ESR signal of substitutional Fe3+ ions

    Paraganglioma of the tongue with SDHB gene mutation in a patient with Graves' disease

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    The authors want to thank Mr. Jose Eduardo Matos (photog-rapher) for his technical assistance.We report a case of an apparently sporadic paraganglioma of the tongue with a germ-line mutation in a female patient with asymptomatic Graves' disease. The tongue is an unusual primary location. Genetic testing is mandatory in all cases. Thyroid gland dysfunction and autoimmune phenomena could be associated with some paragangliomas.S

    Choroid Plexus Papillomas in two Siblings: Case Report [İki Kardeşte Görülen Koroid Pleksus Papillomu: Olgu Sunumu]

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    Choroid plexus papilloma (CPP) is a rare, benign epithelial brain tumor of the nervous system seen particularly in infants. Familial cases are extremely uncommon. Some other form of malignant tumors was noted in the relatives of patients with CPPs, and some genetic defects regarding this coincidence were reported in the literature. These neoplasms are occasionally bilateral and hydrocephalus is an associated sign in most of the cases. We report three lateral ventricle CPPs in two siblings, at the age of 7 month and 2 years respectively. All tumors were resected with parietotemporal craniotomy and a superior temporal sulcus approach to the lateral ventricle. To avoid a concomitant need of ventriculoperitoneal shunt insertion, external ventricular drainage was inserted for a week in the postoperative period relieving symptoms of hydrocephalus. Search for a hereditary defect in the p53 gene of the second infant (7 months old) revealed no mutation. Postoperative courses were uneventful and the patients were followed for three years without any recurrence. Bilateral CPPS are rare and unusual in two siblings. A genetic predisposition such as the p53 mutation should be investigated in bilateral CPPs in particular

    Steady late quaternary slip rate on the Cinarcik section of the North Anatolian fault near Istanbul, Turkey

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    The distribution of plate motion between multiple fault strands and how this distribution may evolve remain poorly understood, despite the key implications for seismic hazards. The North Anatolian Fault in northwest Turkey is a prime example of a multistranded continental transform. Here we present the first constraints on late Quaternary slip rates on its northern branch across the Cinarcik Basin in the eastern Marmara Sea. We use both deep penetration and high‐resolution multichannel seismic reflection data with a stratigraphic age model to show that a depocenter has persisted near the fault bend responsible for that transform basin. Successively older depocenters have been transported westward by fault motion relative to Eurasia, indicating a uniform right‐lateral slip rate of 18.5 mm/yr over the last 500,000 years, compared to overall GPS rates (23–24 mm/yr). Thus, the northern branch has slipped at a nearly constant rate and has accounted for most of the relative plate motion between Eurasia and Anatolia since ~0.5 Ma

    Monitorização do vale e pico sérico de vancomicina em recém-nascidos de termo: comparação entre as técnicas de cromatografia líquida de alta eficácia e imunoensaio por fluorescência polarizada

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    INTRODUCTION: Peak and trough serum concentrations of vancomycin were determined in term newborn infants with confirmed or suspected Staphylococcus sp sepsis by high performance liquid chromatography and flourescence polarization immunoassay. OBJECTIVE: To statistically compare the results of the high performance liquid chromatography and flourescence polarization immunoassay techniques for measuring serum vancomycin concentrations. METHODS: Eighteen peak and 20 trough serum samples were assayed for vancomycin concentrations using high performance liquid chromatography and flourescence polarization immunoassay from October 1995 to October 1997. RESULTS: The linear correlation coefficients for high performance liquid chromatography and flourescence polarization immunoassay were 0.27 (peak, P = 0.110) and 0.26 (trough, P = 0.1045) respectively, which were not statistically significant. CONCLUSION: There was wide variation in serum vancomycin concentrations determined by high performance liquid chromatography as compared with those determined by flourescence polarization immunoassay. There was no recognizable pattern in the variability; in an apparently random fashion, the high performance liquid chromatography measurement was sometimes substantially higher than the flourescence polarization immunoassay measurement, and at other times it was substantially lower.INTRODUÇÃO: Foi realizada monitorização dos níveis séricos de vancomicina em recém-nascidos de termo com sepse ou suspeita de sepse Staphylococcus sp., através da cromatografia líquida de alta eficácia (HPLC) e imunoensaio por fluorescência polarizada (FPIA). OBJETIVO: Verificar a existência de correlação estatística entre os resultados obtidos pelas duas técnicas. MÉTODO E CASUÍSTICA: Foram obtidas dezoito e vinte concentrações séricas de vancomicina no pico e vale respectivamente, em recém-nascidos de termo, no período de outubro de 1995 a outubro de 1997. RESULTADO: O coeficiente de correlação linear para pico sérico foi de 0,27, p=0,110 e para vale sérico 0,26, p= 0,1045 não sendo estatisticamente significativo, não sendo estatisticamente significativo. CONCLUSÃO: Apesar da pequena casuística, não houve correlação estatisticamente significante entre os resultados obtidos pelos duas técnicas

    Ion synthesis and FMR studies of iron and cobalt nanoparticles in polyimides

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    Polyimide foils were implanted with 40 keV Fe+ and Co + to doses of 0.25-1.5×1017 ions/cm2. Electron microscopy studies showed the formation of iron and cobalt nanoparticles in the implanted polymer layer with a thickness of about 70 nm. The size and shape of the ion-synthesized metal nanoparticles depend on the implantation parameters and subsequent thermal annealing. A ferromagnetic resonance (FMR) response was found in the iron-implanted samples as well as in the annealed cobalt and iron samples. The effective magnetization values of the metal/polymer composite layers were extracted from the FMR spectra and plotted as a function of implantation dose. The magnetic properties of the iron and cobalt nanoparticles in polyimide are compared and discussed. © 2003 Elsevier B.V. All rights reserved

    An example of secondary fault activity along the North Anatolian Fault on the NE Marmara Sea Shelf, NW Turkey

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    Seismic data on the NE Marmara Sea Shelf indicate that a NNE-SSW-oriented buried basin and ridge system exist on the sub-marine extension of the Paleozoic Rocks delimited by the northern segment of the North Anatolian Fault (NS-NAF), while seismic and multi-beam bathymetric data imply that four NW-SE-oriented strike-slip faults also exist on the shelf area. Seismic data indicate that NW-SE-oriented strike-slip faults are the youngest structures that dissect the basin-ridge system. One of the NW-SE-oriented faults (F1) is aligned with a rupture of the North Anatolian Fault (NAF) cutting the northern slope of the Cinarcik Basin. This observation indicates that these faults have similar characteristics with the NS-NAF along the Marmara Sea. Therefore, they may have a secondary relation to the NAF since the principle deformation zone of the NAF follows the Marmara Trough in that region. The seismic energy recorded on these secondary faults is much less than that on the NAF in the Marmara Sea. These faults may, however, produce a large earthquake in the long term
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