181 research outputs found

    On the arithmetic sums of Cantor sets

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    Let C_\la and C_\ga be two affine Cantor sets in R\mathbb{R} with similarity dimensions d_\la and d_\ga, respectively. We define an analog of the Bandt-Graf condition for self-similar systems and use it to give necessary and sufficient conditions for having \Ha^{d_\la+d_\ga}(C_\la + C_\ga)>0 where C_\la + C_\ga denotes the arithmetic sum of the sets. We use this result to analyze the orthogonal projection properties of sets of the form C_\la \times C_\ga. We prove that for Lebesgue almost all directions θ\theta for which the projection is not one-to-one, the projection has zero (d_\la + d_\ga)-dimensional Hausdorff measure. We demonstrate the results on the case when C_\la and C_\ga are the middle-(1-2\la) and middle-(1-2\ga) sets

    Kinetic and thermodynamic investigations of strontium ions retention by natural kaolinite and clinoptilolite minerals

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    The current study was devoted to the determination of various thermodynamic and kinetic parameters resulting from the fixation of Sr2+ by natural samples of kaolinite and clinoptilolite minerals. The sorption process followed pseudo second order kinetics, with faster sorption on kaolinite compared to clinoptilolite, where the uptake is affected by intraparticle diffusion. Freundlich and Dubinin-Radushkevich isotherm models described the data more adequately than Langmuir model, and clinoptilolite showed a higher strontium sorption capacity than kaolinite. Thermodynamically, the activation energy of Sr2+ sorption by kaolinite and clinoptilolite were respectively, -8.5 and -18.4 kJ/mol. The sorption process on both minerals was spontaneous and endothermic at all the studied concentrations, with ΔH° being 11.3 and 9.8 kJ/mol, for sorption on kaolinite and clinoptilolite, respectively. The findings of this study were compared with those of an earlier study on the uptake of Cs+ by the same minerals.İYTE: 2003 İYTE 0

    Growth and uptake of sodium and potassium in broad bean (Vicia faba L.) under salinity stress

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    Vicia faba L. (broad bean or faba bean), a food crop of worldwide importance, is moderately tolerant of saline conditions, such as are increasingly common in Mediterranean countries and in Turkey. Our objective was to determine the influence of two salinity levels [50 and 100 mM sodium chloride (NaCl)] and two potassium salts, potassium nitrate (KNO3) (N1 and N2) or potassium acetate (CH3COOK) (A1 and A2), on the development of seedlings of two cultivars of broad bean (cvs. Eresen 87 and Filiz 99) grown in pots of perlite under controlled greenhouse conditions. Flame photometer (FP) analysis of tissues from roots, stems, and leaves of 3-month-old seedlings showed significant differences in growth, internodal length, and potassium (K+)/sodium (Na+) ratios. The FP analyses revealed that Na+ was the ion most responsible for inhibition of growth parameters seen in both cultivars and salt treatments. K+ contents were consistently higher in cv. Filiz 99 than in cv. Eresen 87. Possible correlations between these data and the tolerance to salinity of these cultivars are discussed

    Effect of magnesium carbonate on the uptake of aqueous zinc and lead ions by natural kaolinite and clinoptilolite

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    Adsorption behavior of Zn2+ and Pb2+ ions on kaolinite and clinoptilolite, originating from natural resources, was studied as a function of contact time and concentration. Zn2+ and Pb2+ ions are quickly adsorbed on both minerals and the uptake of the latter is more favored. The uptake of both ions was then examined on kaolinite–MgCO3 and clinoptilolite–MgCO3 mixtures over a metal ions range from 1 to 10 000 mg/L. The sorption behavior of Zn2+ and Pb2+ on pure MgCO3 was also studied. MgCO3 is much more effective in the retention of Zn2+ and Pb2+ ions, in particular at higher concentrations. The large increase in the retarded amounts of both ions was associated with formation of the hydroxy-carbonate phases; namely hydrozincite for Zn2+, and cerussite and hydrocerussite in the case of Pb2+

    Determination of plutonium in seawater using co-precipitation and inductively coupled plasma mass spectrometry with ultrasonic nebulisation1

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    A flow injection–inductively coupled plasma–mass spectrometric (FI–ICP–MS) procedure, utilising ultrasonic nebulisation with membrane desolvation (USN/MD), has been developed for the determination of plutonium (Pu) in seawater at fg l−1 concentration levels. Seawater samples (1 l), after filtration, were subjected to co-precipitation with NdF3, followed by ion exchange to enrich Pu and to reject seawater matrix ions and co-existing uranium. The seawater concentrate (1.0 ml) was then analysed by FI–ICP–MS. The limit of detection for in seawater based on an enrichment factor of 1000 was 5 fg l−1, and precision at the 0.80 pg l−1 level was 12% RSD. Accuracy was verified via recovery experiments, and by comparing survey data for the Irish Sea with that derived by standard methodology based on co-precipitation and α-spectrometry. Concentrations for dissolved in the Irish Sea were in the range of 0.267–0.941 pg l−1 (0.614–2.164 mBq l−1) and 0.051–0.196 pg l−1 (0.428–1.646 mBq l−1), respectively

    Calvarial bone defects in ovariectomised rats treated with mesenchymal stem cells and demineralised freeze-dried bone allografts

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    Background: The aim of the study was to investigate the ability of a combination of bone marrow mesenchymal stem cells (BM-MSCs) with and without demineralised freeze-dried bone allografts (DFDBAs) to induce bone regeneration incalvarial defects in ovariectomised rats.Materials and methods: Critical size defects were filled with a combination of DFDBAs and BM-MSCs or BM-MSCs alone. Eight weeks after calvarial surgery, the rats were sacrificed. The samples were analysed histologically and immunohistochemically.Results: No difference was observed in vascularisation between groups C1 (animals with cranial defect only, control group) and O1 (animals with cranial defect only, ovariectomy group). Intramembranous ossification was observed at a limited level in groups C2 (animals with cranial defect with MSCs, control group) and O2 (animals with cranial defect with MSCs, ovariectomy group) compared to C1 and O1. In group C3 (animals with DFDBAs with MSCs, control group), the fibrous structures of the matrix became compact as a result of a bone graft having been placed in the cavity, but in group O3 (animals with DFDBAs with MSCs, ovariectomy group), the fibrous tissue was poorly distributed between the bone grafts for the most parts.Conclusions: We conclude that the insertion of BM-MSCs enhances bone healing; however, the DFDBA/BM-MSC combination has little effect on overcoming impaired bone formation in ovariectomised rats

    Probing subcellular iron availability with genetically encoded nitric oxide biosensors

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    Cellular iron supply is required for various biochemical processes. Measuring bioavailable iron in cells aids in obtaining a better understanding of its biochemical activities but is technically challenging. Existing techniques have several constraints that make precise localization difficult, and the lack of a functional readout makes it unclear whether the tested labile iron is available for metalloproteins. Here, we use geNOps; a ferrous iron-dependent genetically encoded fluorescent nitric oxide (NO) biosensor, to measure available iron in cellular locales. We exploited the nitrosylation-dependent fluorescence quenching of geNOps as a direct readout for cellular iron absorption, distribution, and availability. Our findings show that, in addition to ferrous iron salts, the complex of iron (III) with N,N’-bis (2-hydroxybenzyl)ethylenediamine-N,N’-diacetic acid (HBED) can activate the iron (II)-dependent NO probe within intact cells. Cell treatment for only 20 min with iron sucrose was also sufficient to activate the biosensor in the cytosol and mitochondria significantly; however, ferric carboxymaltose failed to functionalize the probe, even after 2 h of cell treatment. Our findings show that the geNOps approach detects available iron (II) in cultured cells and can be applied to assay functional iron (II) at the (sub)cellular level.Vifor Pharm

    Use of line spectral frequencies for emotion recognition from speech

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    We propose the use of the line spectral frequency (LSF) features for emotion recognition from speech, which have not been been previously employed for emotion recognition to the best of our knowledge. Spectral features such as mel-scaled cepstral coefficients have already been successfully used for the parameterization of speech signals for emotion recognition. The LSF features also offer a spectral representation for speech, moreover they carry intrinsic information on the formant structure as well, which are related to the emotional state of the speaker. We use the Gaussian mixture model (GMM) classifier architecture, that captures the static color of the spectral features. Experimental studies performed over the Berlin Emotional Speech Database and the FAU Aibo Emotion Corpus demonstrate that decision fusion configurations with LSF features bring a consistent improvement over the MFCC based emotion classification rates.TUBİTAK ; Bahçeşehir University Research Fun

    Differential effects of age of acquisition and frequency on memory: evidence from free recall of pictures and words in Turkish

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    The advantage of processing early acquired items over late acquired items in lexical and semantic tasks across a number of languages is well documented. Interestingly contradictory evidence has been reported in recall tasks where participants perform better overall on late acquired items compared to early acquired items in English (Dewhurst, Hitch & Barry, 1998). Moreover, free recall has also been reported to be modulated by frequency as well as list type in that studying pure lists of high frequency words or low frequency words typically leads to a recall advantage for high frequency words (Dewhurst, Brandt & Sharp, 2004). This recall advantage either disappears or is reversed when the same items are presented in mixed lists containing both high and low frequency items (Dewhurst et al, 2004). The current experiment aims to shed further light on this discrepancy by exploring the influence of AoA and frequency on free recall on standardised pictures and their names (words) in Turkish in mixed and pure lists (Raman, Raman & Mertan, 2014). Eighty participants were recruited from Yeditepe University and were assigned to either a picture (N=40) or a word condition (N=40) in which stimuli were presented in either a mixed or a pure list. Following a distracter task, participants were asked to recall as many pictures or words as they could remember from the list they viewed. The findings lend partial support to the previous findings in English and the implications are discussed within the context of current cognitive frameworks

    Pre-operative Arterial Embolization of Symptomatic Giant Hemangioma of the Liver

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    Abstract: The cavernous hemangiomas of the liver are usually small sized and asymptomatic. Most of them are incidentally diagnosed and a very small portion requires therapy. Giant hemangioma can be symptomatic, and this condition is the indication for treatment. The striking complication of surgical treatment of cavernous hemangiomas is intra-operative bleeding. In this case, we aimed to demonstrate that the risk of intraoperative bleeding can be eliminated with the preoperative percutaneous trans-catheter arterial embolization technique
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