90 research outputs found

    Error bound of certain Gaussian quadrature rules for trigonometric polynomials

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    In this paper we give error bound for quadrature rules of Gaussian type for trigonometric polynomials with respect to the weight function w(x) = 1+cos x, x ∈ (−π, π), for 2π -periodic integrand, analytic in a circular domain. Obtained theoretical bound is checked and illustrated on some numerical examples

    Error bound of certain Gaussian quadrature rules for trigonometric polynomials

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    In this paper we give error bound for quadrature rules of Gaussian type for trigonometric polynomials with respect to the weight function w(x) = 1+cos x, x ∈ (−π, π), for 2π -periodic integrand, analytic in a circular domain. Obtained theoretical bound is checked and illustrated on some numerical examples

    Leaching kinetics of Cs+ and Co2+ under dynamic conditions

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    The possibility of retaining Cs+ and Co2+ bound by immobilization processes in the cement matrix is defined as the subject of its investigation: the cement matrix formulation, the water/ cement ratio, the amount of waste, and the porosity of such a structure. Implementing the standard leaching method by Hespe the possibility of comparing different authors’ results was achieved. Diffusion and semi-empirical model were used to investigate the transport phenomenon in order to predict the leaching level for a long period of time. Leaching of Co2+ and Cs+ ions under dynamic conditions immobilized in the cement matrix dynamic conditions decreases with the increase of the sludge content, regarding porosity increase. The effects of the diffusion and surface washing are equalized, and the contribution ofthe matrix dissolution to the Cs + and Co2+ transport in the cement porous media increases, on average, for one order of magnitude. The semi-empirical model gives a better approximation for Co2+ and Cs+ leaching process for the duration ofthe experiment while both models significantly approximate leaching results in dynamic conditions. © 2019, Vinca Inst Nuclear Sci. All rights reserved

    Da li holesterol vezan za hemoglobin utiče na anti-oksidativni enzimski sistem u humanim eritrocitima?

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    In a previous study, it was shown that the lipid fraction, which is occasionally observed in red blood cell hemolysates, represents cholesterol (Ch) associated with phospholipid firmly bound to haemoglobin (termed Hb-Ch). The current study was conducted to investigate whether Hb-Ch could affect the primary anti-oxidant enzyme defence system in human erythrocytes. Sixty healthy volunteers were used for the current study. Group 1 consisted of 28 subjects without or with a low level of Hb-Ch. Group 2 comprised 32 subjects with a considerably higher level of Hb-Ch. The activities of erythrocyte superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, as well as the content of methaemoglobin (metHb) were measured in both groups. The results indicated that the amount of Hb-Ch neither influenced the activities of the erythrocyte anti-oxidant enzymes nor altered the level of metHb. However, a higher amount of Hb-Ch changed the correlations in the part of the anti-oxidant defence system relating to glutathione, suggesting increased peroxidative pressure from plasma lipids. Group 2 also had significantly increased concentrations of total plasma Ch and triglycerides. Together, these facts are strong indications that the anti-oxidant defence system in human erythrocytes finely retunes its composition according to plasma oxidative demands.U prethodnom radu pokazano je da lipidna frakcija koja se javlja u hemolizatu zdravih ljudi predstavlja holesterol (asosovan sa fosfolipidima) čvrsto vezan za hemoglobin (Hb-Ch). U ovom radu ispitivan je uticaj Hb-Ch na anti-oksidativni enzimski sistem u humanim eritrocitima. Određena je aktivnost superoksid-dizmutaze, katalaze, glutation-peroksidaze i glutation-reduktaze, kao i sadržaj met-hemoglobina (metHb) u eritrocitima 60 ljudi, podeljenih u dve grupe na osnovu količine Hb-Ch. Rezultati pokazuju da količina prisutnog Hb-Ch ne menja aktivnost merenih enzima, niti nivo metHb. Međutim, u grupi ispitanika sa povećanim sadržajem Hb-Ch zapažene su korelativne promene u delu anti-oksidativnog enzimskog sistema povezanog sa glutationom. U istoj grupi detektovane su i veće koncentracije ukupnog holesterola i triglicerida u plazmi, što zajedno ukazuje na povećani peroksidativni pritisak iz plazme. Ovi rezultati ukazuju da odbrambeni anti-oksidativni enzimski sistem u humanim eritrocitima prilagođava svoju organizaciju prema zahtevima iz svog okruženja.

    An Ancient Duplication of Exon 5 in the Snap25 Gene Is Required for Complex Neuronal Development/Function

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    Alternative splicing is an evolutionary innovation to create functionally diverse proteins from a limited number of genes. SNAP-25 plays a central role in neuroexocytosis by bridging synaptic vesicles to the plasma membrane during regulated exocytosis. The SNAP-25 polypeptide is encoded by a single copy gene, but in higher vertebrates a duplication of exon 5 has resulted in two mutually exclusive splice variants, SNAP-25a and SNAP-25b. To address a potential physiological difference between the two SNAP-25 proteins, we generated gene targeted SNAP-25b deficient mouse mutants by replacing the SNAP-25b specific exon with a second SNAP-25a equivalent. Elimination of SNAP-25b expression resulted in developmental defects, spontaneous seizures, and impaired short-term synaptic plasticity. In adult mutants, morphological changes in hippocampus and drastically altered neuropeptide expression were accompanied by severe impairment of spatial learning. We conclude that the ancient exon duplication in the Snap25 gene provides additional SNAP-25-function required for complex neuronal processes in higher eukaryotes

    Reduced Proliferation in the Adult Mouse Subventricular Zone Increases Survival of Olfactory Bulb Interneurons

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    Neurogenesis in the adult brain is largely restricted to the subependymal zone (SVZ) of the lateral ventricle, olfactory bulb (OB) and the dentate subgranular zone, and survival of adult-born cells in the OB is influenced by factors including sensory experience. We examined, in mice, whether survival of adult-born cells is also regulated by the rate of precursor proliferation in the SVZ. Precursor proliferation was decreased by depleting the SVZ of dopamine after lesioning dopamine neurons in the substantia nigra compacta with 6-hydroxydopamine. Subsequently, we examined the effect of reduced SVZ proliferation on the generation, migration and survival of neuroblasts and mature adult-born cells in the SVZ, rostral migratory stream (RMS) and OB. Proliferating cells in the SVZ, measured by 5-bromo-2-deoxyuridine (BrdU) injected 2 hours prior to death or by immunoreactivity against Ki67, were reduced by 47% or 36%, respectively, 7 days after dopamine depletion, and by 29% or 31% 42 days after dopamine depletion, compared to sham-treated animals. Neuroblast generation in the SVZ and their migration along the RMS were not affected, neither 7 nor 42 days after the 6-hydroxydopamine injection, since the number of doublecortin-immunoreactive neuroblasts in the SVZ and RMS, as well as the number of neuronal nuclei-immunoreactive cells in the OB, were stable compared to control. However, survival analysis 15 days after 6-hydroxydopamine and 6 days after BrdU injections showed that the number of BrdU+ cells in the SVZ was 70% higher. Also, 42 days after 6-hydroxydopamine and 30 days after BrdU injections, we found an 82% increase in co-labeled BrdU+/γ-aminobutyric acid-immunoreactive cell bodies in the granular cell layer, while double-labeled BrdU+/tyrosine hydroxylase-immunoreactive cell bodies in the glomerular layer increased by 148%. We conclude that the number of OB interneurons following reduced SVZ proliferation is maintained through an increased survival of adult-born precursor cells, neuroblasts and interneurons

    The politics of performance: transnationalism and its limits in former Yugoslav popular music, 1999–2004

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    This paper examines transnational relations between the Yugoslav successor states from the point of view of popular music, and demonstrates how transnational musical figures (such as Djordje Balaševi?, Mom?ilo Bajagi?-Bajaga and Ceca Ražnatovi?) are interpreted as symbolic reference points in national ethnopolitical discourse in the process of identity construction. Another symbolic function is served by Serbian turbofolk artists, who in Croatia serve as a cultural resource to distance oneself from a musical genre associated by many urban Croats with the ruralization (and Herzegovinization) of Croatian city space. In addition, value judgements associated with both Serbian and Croatian newly composed folk music provide an insight into the transnational negotiation of conflicting identities in the ex-Yugoslav context. Ultimately the paper shows how the ethnonational boundaries established by nationalizing ideologies created separate cultural spaces which themselves have been transnationalized after Yugoslavia's disintegration
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