134 research outputs found

    High-K volcanism in the Afyon region, western Turkey: from Si-oversaturated to Si-undersaturated volcanism

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    Volcanic rocks of the Afyon province (eastern part of western Anatolia) make up a multistage potassic and ultrapotassic alkaline series dated from 14 to 12 Ma. The early-stage Si-oversaturated volcanic rocks around the Afyon city and further southward are trachyandesitic volcanic activity (14.23 ± 0.09 Ma). Late-stage Si-undersaturated volcanism in the southernmost part of the Afyon volcanic province took place in three episodes inferred from their stratigraphic relationships and ages. Melilite– leucitites (11.50 ± 0.03 Ma), spotted rachyandesites, tephryphonolites and lamproites (11.91 ± 0.13 Ma) formed in the first episode; trachyandesites in the second episode and finally phonotephrites, phonolite, basaltic trachyandesites and nosean-bearing trachyandesites during the last episode. The parameter Q [normative q-(ne + lc + kls + ol)] of western Anatolia volcanism clearly decreased southward with time becoming zero in the time interval 10–15 Ma. The magmatism experienced a sudden change in the extent of Si saturation after 14 Ma, during late-stage volcanic activity of Afyon volcanic province at around 12 Ma, though there was some coexistence of Si-oversaturated and Si-undersaturated magmas during the whole life of Afyon volcanic province

    TIMP-2 gene transfer by positively charged PEG-lated monosized polycationic carrier to smooth muscle cells

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    Remodeling of the extracellular matrix resulting from increased secretion of metalloproteinase enzymes is implicated in restenosis following balloon angioplasty. Matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases play an essential role in both normal and pathological extracellular matrix degradation. Tissue inhibitor of matrix metalloproteinase- 2 is the most extensively studied tissue inhibitor of metalloproteinases inmyocardial tissue in animalmodels and clinical examples of cardiac disease; therefore it is selected for this study. Gene transfer of tissue inhibitor of matrix metalloproteinase-2 may have a therapeutic potential by inhibition of matrix metalloproteinase activity. We have used PEG-lated nanoparticles poly(St/PEG-EEM/DMAPM) which were synthesized previously in our laboratory. The nanoparticles, with an average size of 77.6 ± 2.05 nm with a zeta potential of +64. 4 ± 1.14 mVand 201.9 ± 1.83 nmwith +54.2 ± 0.77 mV were used in the transfection studies. Zeta Potential values and size of polyplex were appropriate for an effective transfection. TIMP-2 expression was detected by western blotting. Increased protein level in smoothmuscle cells according to non-transfected smooth muscle cells confirms the successful delivery and expression of the tissue inhibitor of matrix metalloproteinase- 2 gene with the non-viral vector transfection approach. © Springer Science+Business Media B.V. 2012

    On the decay and blow up of solutions for a quasilinear hyperbolic equations with nonlinear damping and source terms

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    In this work we investigate the global existence, decay, and blow up of solutions for a quasilinear hyperbolic equation. We prove the decay estimates of the energy function by using Nakao's inequality. Also, we obtain the blow up of solutions and lifespan estimates in three different ranges of the initial energy

    Archaeogenetic analysis of Neolithic sheep from Anatolia suggests a complex demographic history since domestication

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    Sheep were among the first domesticated animals, but their demographic history is little understood. Here we analyzed nuclear polymorphism and mitochondrial data (mtDNA) from ancient central and west Anatolian sheep dating from Epipaleolithic to late Neolithic, comparatively with modern-day breeds and central Asian Neolithic/Bronze Age sheep (OBI). Analyzing ancient nuclear data, we found that Anatolian Neolithic sheep (ANS) are genetically closest to present-day European breeds relative to Asian breeds, a conclusion supported by mtDNA haplogroup frequencies. In contrast, OBI showed higher genetic affinity to present-day Asian breeds. These results suggest that the east-west genetic structure observed in present-day breeds had already emerged by 6000 BCE, hinting at multiple sheep domestication episodes or early wild introgression in southwest Asia. Furthermore, we found that ANS are genetically distinct from all modern breeds. Our results suggest that European and Anatolian domestic sheep gene pools have been strongly remolded since the Neolithic

    Kinetic, Isotherm and Thermodynamic Analysis on Adsorption of Cr(VI) Ions from Aqueous Solutions by Synthesis and Characterization of Magnetic-Poly(divinylbenzene-vinylimidazole) Microbeads

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    The magnetic-poly(divinylbenzene-1-vinylimidazole) [m-poly(DVB-VIM)] microbeads (average diameter 53–212 μm) were synthesized and characterized; their use as adsorbent in removal of Cr(VI) ions from aqueous solutions was investigated. The m-poly(DVB-VIM) microbeads were prepared by copolymerizing of divinylbenzene (DVB) with 1-vinylimidazole (VIM). The m-poly(DVB-VIM) microbeads were characterized by N2 adsorption/desorption isotherms, ESR, elemental analysis, scanning electron microscope (SEM) and swelling studies. At fixed solid/solution ratio the various factors affecting adsorption of Cr(VI) ions from aqueous solutions such as pH, initial concentration, contact time and temperature were analyzed. Langmuir, Freundlich and Dubinin–Radushkvich isotherms were used as the model adsorption equilibrium data. Langmuir isotherm model was the most adequate. The pseudo-first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models were used to describe the adsorption kinetics. The apparent activation energy was found to be 5.024 kJ mol−1, which is characteristic of a chemically controlled reaction. The experimental data fitted to pseudo-second-order kinetic. The study of temperature effect was quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes. The thermodynamic parameters obtained indicated the endothermic nature of adsorption of Cr(VI) ions. Morever, after the use in adsorption, the m-poly(DVB-VIM) microbeads with paramagnetic property were separeted via the applied magnetic force. The magnetic beads could be desorbed up to about 97% by treating with 1.0 M NaOH. These features make the m-poly(DVB-VIM) microbeads a potential candidate for support of Cr(VI) ions removal under magnetic field

    The population history of domestic sheep revealed by Paleogenomes

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    Sheep was one of the first domesticated animals in Neolithic West Eurasia. The zooarchaeological record suggests that domestication first took place in Southwest Asia, although much remains unresolved about the precise location(s) and timing(s) of earliest domestication, or the post-domestication history of sheep. Here, we present 24 new partial sheep paleogenomes, including a 13,000-year-old Epipaleolithic Central Anatolian wild sheep, as well as 14 domestic sheep from Neolithic Anatolia, two from Neolithic Iran, two from Neolithic Iberia, three from Neolithic France, and one each from Late Neolithic/Bronze Age Baltic and South Russia, in addition to five present-day Central Anatolian Mouflons and two present-day Cyprian Mouflons. We find that Neolithic European, as well as domestic sheep breeds, are genetically closer to the Anatolian Epipaleolithic sheep and the present-day Anatolian and Cyprian Mouflon than to the Iranian Mouflon. This supports a Central Anatolian source for domestication, presenting strong evidence for a domestication event in SW Asia outside the Fertile Crescent, although we cannot rule out multiple domestication events also within the Neolithic Fertile Crescent. We further find evidence for multiple admixture and replacement events, including one that parallels the Pontic Steppe-related ancestry expansion in Europe, as well as a post-Bronze Age event that appears to have further spread Asia-related alleles across global sheep breeds. Our findings mark the dynamism of past domestic sheep populations in their potential for dispersal and admixture, sometimes being paralleled by their shepherds and in other cases not.Middle Eastern Studie

    Biodegradable polymeric matrices for bioartificial implants

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    Biomaterials made of polymers, metals or their alloys, ceramics and their composites, are used as implants to restore or to replace the damaged soft and hard tissue/organ functions for an intended time period. Biomaterials made of synthetic materials are very simple materials compared to their natural counterparts, they only replace very simple functions of the damaged tissue during healing. Natural tissues have been used for both soft and hard repair and replacement, but they do have serious limitations such as: shortage of donor tissue, donor site morbidity, unpredictable resorption characteristics, immunogenic response, risk of disease transmission, and ethical limitations. Tissue engineering is a relatively new approach, in which healthy mammalian cells are used with supporting matrices, usually made of either natural or synthetic polymers as composite bioartificial implants. Primary cells, especially embryonic stem cells, cell lines, hybridomas, genetically modified cells are considered as potential sources for this application. Both closed and open matrices are used as support matrices. Nondegradable and biocompatible microcapsules and hollow fibers are utilized in closed systems, especially for immunoprotection of the transplanted cells. Biodegradable polymers, both natural and synthetic are used in the preparation of bioartificial implants carrying only autogenic cells. </jats:p

    Poly(α-Hydroxy Acid) Based Polymeric Biomaterials and their Composites

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    A lower bound for the blow up time of a system of viscoelastic wave equations with nonlinear damping and source terms

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    In this paper, we consider the blow up of an initial and boundary value problem for a system of viscoelastic wave equations (Equation presented) Lower bounds for the blow up time of the blow up solutions is given. © 2017 Journal of Nonlinear Functional Analysis
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