33 research outputs found

    Studies on correlations between immunophenotype and the indices of metabolic enzyme activity of blood lymphocytes in children with hypertrophy of the pharyngeal tonsils

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    The objective of our study was to evaluate correlation between the immune pheno-type and activity indices of NAD (P)-dependent dehydrogenases in peripheral blood lymphocytes in young children with hypertrophy of the pharyngeal tonsil (HPT). We have examined 57 children, 1-3 years of age, with hypertrophy of the pharyngeal tonsils (HPT). The control group consisted of 35 healthy children of the same age. The numbers of CD3+, CD4+, CD8+, CD19+, CD16+/56+ lymphoid cells in peripheral blood were determined by flow cytofluorimetry technique. Activity of NAD (P)-dependant dehydrogenases in peripheral blood lymphocytes was studied using bioluminescent method as described elsewhere (А. Savchenko, L. Suntsova, 1989). Correlation analysis has revealed an increase of positive correlations, a decrease of the correlation strength, and emergence of new connections between phenotype and activity indices of NAD (P)-dependent dehydrogenases in peripheral blood lymphocytes in children with hypertrophy of pharyngeal tonsils (HPT). Specific correlation patterns between the phenotype and activity indices of NAD (P)-dependent dehydrogenases in peripheral blood lymphocytes have been revealed in children with hypertrophy of pharyngeal tonsils (HPT)

    Paleointensity determination on Neoarchaean dikes within the Vodlozerskii terrane of the Karelian craton

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    © 2017, Pleiades Publishing, Ltd. The results of paleomagnetic studies and paleointensity determinations from two Neoarchaean Shala dikes with an age of ~2504 Ma, located within the Vodlozerskii terrane of the Karelian craton, are presented. The characteristic components of primary magnetization with shallow inclinations I = −5.7 and 1.9 are revealed; the reliability of the determinations is supported by two contact tests. High paleointensity values are obtained by the Thellier–Coe and Wilson techniques. The calculated values of the virtual dipole moment (11.5 and 13.8) × 10 22 A m 2 are noticeably higher than the present value of 7.8 × 10 22 A m 2 . Our results, in combination with the previous data presented in the world database, support the hypothesized existence of a period of high paleointensity in the Late Archaean–Early Proterozoic

    Extreme sensitivity in Snowball Earth formation to mountains on PaleoProterozoic supercontinents

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    During the PaleoProterozoic 2.45 to 2.2 billion years ago, several glaciations may have produced Snowball Earths. These glacial cycles occurred during large environmental change when atmospheric oxygen was increasing, a supercontinent was assembled from numerous landmasses, and collisions between these landmasses formed mountain ranges. Despite uncertainties in the composition of the atmosphere and reconstruction of the landmasses, paleoclimate model simulations can test the sensitivity of the climate to producing a Snowball Earth. Here we present a series of simulations that vary the atmospheric methane concentration and latitudes of west–east-oriented mountain ranges on an idealised supercontinent. For a given methane concentration, the latitudes of mountains control whether a Snowball Earth forms or not. Significantly, mountains in middle latitudes inhibited Snowball Earth formation, and mountains in low latitudes promoted Snowball Earth formation, with the supercontinent with mountains at ±30° being most conducive to forming a Snowball Earth because of reduced albedo at low latitudes. We propose that the extreme sensitivity of a Snowball Earth to reconstructions of the paleogeography and paleoatmospheric composition may explain the observed glaciations, demonstrating the importance of high-quality reconstructions to improved understanding of this early period in Earth’s history

    Paleomagnetic study of NeoArchean-Paleoproterozoic dykes in the Kaapvaal Craton

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    431 oriented samples were collected from 27 dolerite dykes at 17 sites, belonging to 2.95, 2.65, and 1.90. Ga swarms, that trend SE, E and NE, respectively from the Bushveld Igneous Complex into the eastern Kaapvaal Craton (ages determined by Olsson et al., 2010; Olsson in Söderlund et al., 2010). Samples were analyzed for paleomagnetism and also anisotropy of magnetic susceptibility (AMS). For the 2.95. Ga SE-trending dykes high temperature/coercivity 'P' component has unblocking temperatures up to 590°C and coercivity 40-90. mT and demonstrate SSW declination and intermediate positive inclination. Based on positive contact and conglomerate tests we argue for a primary origin of this component. The paleopole (BAD), calculated from '. P' component, does not correspond to any of the previously obtained Archean-Paleoproterozoic paleopoles for the Kaapvaal Craton, and represents a new key pole for 2.95. Ga. The high-coercivity '. H' component for the 2.65. Ga-old E-trending dykes has a SSW declination and steep positive inclination. Paleomagnetic pole (RYK), recalculated from this component, is close to the paleopoles, obtained by Wingate (1998) and Strik et al. (2007) for 2.78. Ga Ventersdorp volcanics. The third group, NE-trending dykes of the 1.90. Ga Black Hill swarm demonstrate an '. M' component with dual polarity high-coercivity component with SSE-declination and negative intermediate inclination. The paleopole (BHD), calculated from this component is close to the 1.87. Ga pole of the Kaapvaal Craton obtained by Hanson et al. (2004). Overprint directions include a very well developed thermo-chemical overprint (Dec. =329° Inc. =-36°), which is believed to be associated with a ∌0.18. Ga regional 'Karoo' thermal event. © 2010 Elsevier B.V.Articl

    Paleointensity determination on Neoarchaean dikes within the Vodlozerskii terrane of the Karelian craton

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    © 2017, Pleiades Publishing, Ltd. The results of paleomagnetic studies and paleointensity determinations from two Neoarchaean Shala dikes with an age of ~2504 Ma, located within the Vodlozerskii terrane of the Karelian craton, are presented. The characteristic components of primary magnetization with shallow inclinations I = −5.7 and 1.9 are revealed; the reliability of the determinations is supported by two contact tests. High paleointensity values are obtained by the Thellier–Coe and Wilson techniques. The calculated values of the virtual dipole moment (11.5 and 13.8) × 10 22 A m 2 are noticeably higher than the present value of 7.8 × 10 22 A m 2 . Our results, in combination with the previous data presented in the world database, support the hypothesized existence of a period of high paleointensity in the Late Archaean–Early Proterozoic

    Fennoscandia before Nuna/Columbia: Paleomagnetism of 1.98–1.96 Ga mafic rocks of the Karelian craton and paleogeographic implications

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    © 2017 Elsevier B.V.Numerous mafic dykes, sills and intrusions with ages between 1985 Ma and 1960 Ma are exposed near the Onega Lake in southern Karelia, Russia. The paleomagnetic analysis of these rocks has revealed a stable remanence with directions belonging to two groups. The directions of the first group characterize ten intrusions including the dated 1970 ± 3 Ma Unoi sill and 1976 ± 9 Ma Suna River Canyon dolerite, the corresponding paleomagnetic pole is 44.4°N, 101.5°E, A95 = 6.3°. The second group comprises two intrusions including the 1984 ± 8 Ma Pudozhgora intrusion and Krestoviy Navolok dyke with the corresponding paleopole calculated from 5 site mean poles is 60.9°N, 144.8°E, A95 = 6.8°. Both remanence directions are supported by robust baked contact tests. We propose the first group's pole as the key 1975 Ma Fennoscandian pole. The second one is well dated, but based only on two intrusions without proper averaging of the paleosecular variations. We have also carried out a complimentary paleomagnetic study of the previously investigated 2504 Ma Shalskiy gabbronorite dyke. The remanence of this dyke is now supported by the inverse contact test and statistics can be improved. Using our 1975 Ma pole together with coeval poles from Superior, Slave and Amazonia cratons we propose a provisional 1975 Ma paleogeographic reconstruction
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