420 research outputs found

    Effects of cold stratification pretreatment and pH level on germination of Centaurea tchihatcheffii Fisch. et Mey. seeds

    Get PDF
    Centaurea tchihatcheffii Fisch. Et. Mey. is a critically endangered (CR) plant species due to destruction of habitat, strong anthropogenic pressure, biotic and abiotic factors. It grows in limited areas in Gölbai district of Ankara, Turkey and in the world. It is very necessary to conserve it and prevent its extinction. Previous studies emphasise that low germination rate of its seed is primarily due to deep seed dormancy. Therefore, studies was done on C. tchihatcheffii seeds, to investigate the effects of cold stratification for different periods (90, 120 and 150 days) and different pH values (pH 6.5, 7.5 and 8.5) on seed germination. The highest germination percentage (58.89 ± 6.39%) was observed in seeds stratified for 150 days at all pH values of growing media, followed by seeds stratified for 120 days (42.78 ± 4.57%). An increase in pH level had negative effects on seed  germination, the lowest germination (27.22 ± 4.18 %) was determined at pH 8.5.Key words: Centaure tchihatcheffii, critically endangered, seed  germination, stratification, pH values

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

    Get PDF
    The Ä°zmir‐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 mĂ©lange, 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 mĂ©lange 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

    The Influence of Temperature and Drug Concentrations Prednisolone in NIPAAm Copolymer

    Get PDF
    Controlled delivery systems would be more beneficial and ideal if the drug could be delivered with respond to external environmental change. It could be used to overcome the shortcomings of conventional dosage forms. Therefore, the correct amount of drug would be released upon the stimulation of such a temperature and concentration change. The purpose of study is to investigate the influence of temperature and drug concentration from poly(2-hydroxyethyl methacrylate and N-isopropylacrylamide)/poly(HEMA-NIPAAm). The macroporous structure 5HEMA15NIPAAm was showed the most rapid responsiveness in swelling ratio, polymer volume fraction, swelling and deswelling kinetics. The high drug loading capacity was achieved at or below ambient temperature, whilst the release profile was revealed sustain release of conventional anti-inflammatory drug; prednisolone 21 hemisuccinate sodium salt. In general, drug loading capacity and drug diffusion kinetics are influence by the porosity of hydrogels, temperature, and drug concentration

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

    Full text link
    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

    Optical and magnetic properties of Ni-implanted and post-annealed ZnO thin films

    Get PDF
    Single-crystalline ZnO thin films have been grown on sapphire substrates and implanted by 40 keV Ni+ ions with a dose of 0.25-1.25 × 1017 ions/cm2. After implantation the samples have been annealed at T = 1000°C for 30 minutes in air. Both as-prepared and annealed nickelimplanted ZnO samples have been investigated by ferromagnetic resonance (FMR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), and optical techniques. SEM studies reveal that the surface of non-implanted ZnO thin film is very smooth, while microcracks are present in the Ni-implanted ZnO samples. Annealing after implantation recovers the surface of the implanted ZnO. Energy dispersive X-ray spectroscopy shows that the Ni concentration increases with increasing the implantation dose. Optical measurements of the Ni-implanted ZnO thin films indicate that annealing results in formation of a new phase. This phase is attributed to NiO that appears due to redistribution and oxidation of the implanted Ni ions in the ZnO matrix. Magnetic measurements show that both as-implanted and annealed samples exhibit roomtemperature ferromagnetism. VSM data indicate that annealing procedure results in decreasing the magnetic moment per Ni atom and higher coercivity at low temperatures. Magnetic-resonance studies reveal highly anisotropic FMR signal in the as-implanted Ni:ZnO samples starting from the dose of 0.5 × 10 17 ions/cm2. We also observe a step-wise increase of the effective magnetization at the dose of 1.0 × 1017 ions/cm 2, which is explained by magnetic percolation of the Ni nanoparticles. Narrow resonance signals with unusual angular dependence are observed in magnetic-resonance studies of the annealed Ni:ZnO samples, which have been related to the formation of a system of non-percolated NiO-coated Ni nanoparticles as a result of annealing in air. We did not observe experimental evidence for intrinsic ferromagnetism in the Ni-implanted ZnO thin films. © Springer-Verlag 2011

    Complex conductivity of soils

    Get PDF
    The complex conductivity of soils remains poorly known despite the growing importance of this method in hydrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including four peat samples) and one clean sand in the frequency range 0.1 Hz to 45 kHz. The soil samples are saturated with six different NaCl brines with conductivities (0.031, 0.53, 1.15, 5.7, 14.7, and 22 S m21, NaCl, 258C) in order to determine their intrinsic formation factor and surface conductivity. This data set is used to test the predictions of the dynamic Stern polarization model of porous media in terms of relationship between the quadrature conductivity and the surface conductivity. We also investigate the relationship between the normalized chargeability (the difference of in-phase conductivity between two frequencies) and the quadrature conductivity at the geometric mean frequency. This data set confirms the relationships between the surface conductivity, the quadrature conductivity, and the normalized chargeability. The normalized chargeability depends linearly on the cation exchange capacity and specific surface area while the chargeability shows no dependence on these parameters. These new data and the dynamic Stern layer polarization model are observed to be mutually consistent. Traditionally, in hydrogeophysics, surface conductivity is neglected in the analysis of resistivity data. The relationships we have developed can be used in field conditions to avoid neglecting surface conductivity in the interpretation of DC resistivity tomograms. We also investigate the effects of temperature and saturation and, here again, the dynamic Stern layer predictions and the experimental observations are mutually consistent

    Long-term results of diaphragmatic plication in adults with unilateral diaphragm paralysis

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>In this study we aimed to evaluate the long-term outcome of diaphragmatic plication for symptomatic unilateral diaphragm paralysis.</p> <p>Methods</p> <p>Thirteen patients who underwent unilateral diaphragmatic plication (2 patients had right, 11 left plication) between January 2003 and December 2006 were evaluated. One patient died postoperatively due to sepsis. The remaining 12 patients [9 males, 3 females; mean age 60 (36-66) years] were reevaluated with chest radiography, flouroscopy or ultrasonography, pulmonary function tests, computed tomography (CT) or magnetic resonance imaging (MRI), and the MRC/ATS dyspnea score at an average of 5.4 (4-7) years after diaphragmatic plication.</p> <p>Results</p> <p>The etiology of paralysis was trauma (9 patients), cardiac by pass surgery (3 patients), and idiopathic (1 patient). The principle symptom was progressive dyspnea with a mean duration of 32.9 (22-60) months before surgery. All patients had an elevated hemidiaphragm and paradoxical movement radiologically prior to surgery. There were partial atelectasis and reccurent infection of the lower lobe in the affected side on CT in 9 patients. Atelectasis was completely improved in 9 patients after plication. Preoperative spirometry showed a clear restrictive pattern. Mean preoperative FVC was 56.7 ± 11.6% and FEV1 65.3 ± 8.7%. FVC and FEV1 improved by 43.6 ± 30.6% (p < 0.001) and 27.3 ± 10.9% (p < 0.001) at late follow-up. MRC/ATS dyspnea scores improved 3 points in 11 patients and 1 point in 1 patient at long-term (p < 0.0001). Eight patients had returned to work at 3 months after surgery.</p> <p>Conclusions</p> <p>Diaphragmatic plication for unilateral diaphragm paralysis decreases lung compression, ensures remission of symptoms, and improves quality of life in long-term period.</p

    Evaporation kinetics in swollen porous polymeric networks

    Get PDF
    Ponencia presentada en el Congreso Euromar 2014.Fil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Velasco, Manuel Isaac. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Silletta, Emilia Victoria. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Monti, Gustavo Alberto. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Departamento de QuĂ­mica OrgĂĄnica; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Departamento de QuĂ­mica OrgĂĄnica; Argentina.Fil: Gomez, Cesar Gerardo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Polymer matrices with well defined structure and pore sizes are widely used in several areas of chemistry such as catalysis, enzyme immobilization, HPLC, adsorbents or controlled drug release. These polymers have pores in its structure both in the dry and swollen state. Although it is well known that the structures and properties greatly differ between these two states, only few methods provide information about the swollen one, even though most of the applications involve the matrices in this situation. Nuclear Magnetic Resonance (NMR) is a suitable tool for the study of the molecular dynamics of different liquids spatially confined in macro, meso and nanopores, through changes in the relaxation times. In transverse relaxation experiments, either diffusion inside the pore, or relaxation induced by mobility restriction of the liquid near the wall, are additional sources of relaxation, which are extremely useful in the determination of structural and functional properties.Fil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Velasco, Manuel Isaac. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Silletta, Emilia Victoria. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Monti, Gustavo Alberto. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Departamento de QuĂ­mica OrgĂĄnica; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Departamento de QuĂ­mica OrgĂĄnica; Argentina.Fil: Gomez, Cesar Gerardo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.FĂ­sica de los Materiales Condensado
    • 

    corecore