| 1. |
- Nosova, A. A., et al.
(författare)
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Early Cambrian Syenite and Monzonite Magmatism in the Southeast of the East European Platform : Petrogenesis and Tectonic Setting
- 2019
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Ingår i: Petrology. - 0869-5911. ; 27:4, s. 329-369
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Tidskriftsartikel (refereegranskat)abstract
- Abstract—The paper reports new geochronological, petrological, and isotope-geochemical data on the syenites and alkali syenites of the Artyushki massif, and the monzonites of the Gusikha massif. These massifs are located along the southwestern and northeastern margins of the Pachelma aulacogen, in the southeastern part of the East European Platform (EEP). They have Early Cambrian ages of 524 ± 3 (Artyushki) and 514 ± 2 Ma (Gusikha) obtained by the U-Pb zircon method and similar ages of amphibole and K-feldspar by the 40Ar/39Ar method. This time period has previously been regarded as amagmatic in the EEP evolution. The Artyushki massif is made up of Amp–Cpx syenite porphyries and Grt–Cpx alkali syenite porphyries and their fenitized varieties. As compared to the Amp–Cpx varieties the Grt–Cpx rocks are more peralkaline (A/NK > 0.9) and have higher LREE and HFSE, and fractionated HREE patterns. The metasomatized (fenitized) varieties are more potassic and bear geochemical evidence of fluid reworking (high Y/Ho ratios, significant Zn variations, and etc.). Bulk samples have weakly radiogenic Sr isotopic compositions: (87Sr/86Sr)520 are within 0.703066–0.703615. The values of εNd(520) vary from –0.69 to +1.64. The Grt–Cpx syenite porphyries have the positive εNd(520), while the Amp–Cpx and fenitized syenite porphyries feature negative εNd. The Gusikha massif consists of biotite–amphibole and biotite monzonites. Similar to the Artyushki syenites in SiO2 contents, the Gusikha monzonites have higher Mg# (0.22–0.54 and 0.34–0.71 for the Artyushki and Gusikha massifs, respectively). They are also characterized by a negative Nb–Ta anomaly (Nb/Nb* = 0.5), high Ва/Sr ratio, and highly radiogenic (87Sr/86Sr)520 = 0.705204 and 0.705320. Their Nd-isotopic compositions correspond to εNd(520) = –6.7 and ‒7.0. Two melts contributed to the formation of the Artyushki massif. One was a strongly contaminated melt (Amp–Cpx syenite porphyries, the other was weakly contaminated (Grt–Cpx syenite porphyries). The main contribution was phonolitic melt derived from the melting of a moderately metasomatized (carbonate- and amphibole-bearing) shallow lithospheric mantle. The earliest and deepest melt portions were carbonate–silicate in composition. The geochemical, as well as the Sr and Nd isotopic compositions of the Gusikha monzonites indicate a predominant crustal contribution and pervasive reworking of the lithospheric mantle beneath southeastern Volgo–Uralia of the EEP in the Mesoproterozoic. Both massifs feature the geochemistry of within-plate and supra-subduction derivatives, which suggests a postorogenic tectonic setting of the magmatism. The presence of the Early Cambrian postorogenic magmatism within the East European Platform/Baltica is direct evidence for the involvement of Baltica in the collisional and/or accretionary events during the terminal Neoproterozoic–the beginning of the Paleozoic. This suggests reworking of the lithospheric mantle of Baltica during its collision with Timanian and East Avalonian/Cadomian terranes, including Scythia.
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| 2. |
- Vaněk, J., et al.
(författare)
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Determination of the homogeneous magnitude system magnitudes in seismological practice
- 1985
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Ingår i: Tectonophysics. - : Elsevier BV. - 0040-1951 .- 1879-3266. ; 118:3-4, s. 359-363
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Tidskriftsartikel (refereegranskat)abstract
- Routine determination of network magnitudes by means of the Eurasian homogeneous magnitude system (HMS) is described and tested on a selection of recent shallow earthquakes. The HMS earthquake magnitudes appear to be more accurate and more reliable than the conventional earthquake magnitudes used in the present seismological practice. A preliminary investigation of correlations between magnitudes determined from different wave types shows a possible dependence of the correlation on the type of focal mechanism of earthquakes
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| 3. |
- Carvalho, Liliana S., et al.
(författare)
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Unilateral brain injury to pregnant rats induces asymmetric neurological deficits in the offspring
- 2021
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Ingår i: European Journal of Neuroscience. - : John Wiley & Sons. - 0953-816X .- 1460-9568. ; 53:11, s. 3621-3633
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Tidskriftsartikel (refereegranskat)abstract
- Effects of environmental factors may be transmitted to the following generation, and cause neuropsychiatric disorders including depression, anxiety, and posttraumatic stress disorder in the offspring. Enhanced synaptic plasticity induced by environmental enrichment may be also transmitted. We here test the hypothesis that the effects of brain injury in pregnant animals may produce neurological deficits in the offspring. Unilateral brain injury (UBI) by ablation of the hindlimb sensorimotor cortex in pregnant rats resulted in the development of hindlimb postural asymmetry (HL-PA), and impairment of balance and coordination in beam walking test in the offspring. The offspring of rats with the left UBI exhibited HL-PA before and after spinal cord transection with the contralesional (i.e., right) hindlimb flexion. The right UBI caused the offspring to develop HL-PA that however was cryptic and not-lateralized; it was evident only after spinalization, and was characterized by similar occurrence of the ipsi- and contralesional hindlimb flexion. The HL-PA persisted after spinalization suggesting that the asymmetry was encoded in lumbar spinal neurocircuits that control hindlimb muscles. Balance and coordination were affected by the right UBI but not the left UBI. Thus, the effects of a unilateral brain lesion in pregnant animals may be intergenerationally transmitted, and this process may depend on the side of brain injury. The results suggest the existence of left-right side-specific mechanisms that mediate transmission of the lateralized effects of brain trauma from mother to fetus.
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| 4. |
- Lukoyanov, Nikolay, et al.
(författare)
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Endocrine signaling mediates asymmetric motor deficits after unilateral brain injury
- 2020
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A paradigm in neurology is that brain injury-induced motor deficits (e.g. hemiparesis and hemiplegia) arise due to aberrant activity of descending neural pathways. We discovered that a unilateral injury of the hindlimb sensorimotor cortex of rats with completely transected thoracic spinal cord produces hindlimb postural asymmetry with contralateral flexion, and asymmetric changes in nociceptive hindlimb withdrawal reflexes and gene expression patterns in lumbar spinal cord. The injury-induced postural effects were abolished by prior hypophysectomy and were mimicked by transfusion of serum from animals with unilateral brain injury. Antagonists of the opioid and vasopressin receptors blocked formation of hindlimb postural asymmetry suggesting that these neurohormones mediate effects of brain injury on lateralized motor responses. Our data indicate that descending neural control of spinal circuits is complemented by a previously unknown humoral signaling from injured brain to the contra- and ipsilesional hindlimbs, and suggest the existence of a body side-specific neuroendocrine regulation in bilaterally symmetric animals.
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| 5. |
- Stasiuk, A. V., et al.
(författare)
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Influence of structure and nature of pseudo-poly(amino acid)s on size and morphology of their particle in self-stabilized aqueous dispersions
- 2023
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Ingår i: Applied Nanoscience. - Germany : Springer. - 2190-5509 .- 2190-5517. ; 13:7, s. 5011-5019
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Tidskriftsartikel (refereegranskat)abstract
- Polyester pseudo-poly(amino acid)s due to their biodegradability and biocompatibility are promising materials for the development of dispersed systems for drug delivery. It is essential for drug delivery systems to reach the target site within a certain period before they are eliminated or degraded. Biodegradable materials should meet the following criteria: (1) possess surface-active properties; (2) be non-toxic; (3) form self-stabilized dispersions with the size of the dispersed phase in the range of 10–100 nm. Polyesters based on N-derivatives of dicarboxylic α-amino acids and hydrophilic PEG diols modified with phosphate group meet the requirements to the dispersed drug delivery systems. Obtained polyesters have a complex architecture consisting of hydrophilic fragments, which stabilize the system, and lipophilic fragments, which solubilize biologically active substances. The phosphate group introduced into the hydrophilic chain of polyoxyethylene glycol provides chemisorption of a number of biologically active substances due to the formation of ionic bonds between them. Synthesized polyesters form self-stabilized dispersed systems, which do not require additional stabilizing agents when used for medical applications.
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| 6. |
- Tennberg, Monica, et al.
(författare)
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Neoliberal governance, sustainable development and local communities in the Barents Region
- 2014
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Ingår i: Barents Studies. - 2324-0652. ; 1:1, s. 41-72
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Tidskriftsartikel (refereegranskat)abstract
- There are currently high hopes in the Barents Region for economic growth, higheremployment and improved well-being, encouraged by developments in the energy industry,tourism and mining. The article discusses these prospects from the perspectiveof local communities in five locations in the region, which spans the northernmostcounties of Finland, Norway, Sweden and Northwest Russia. The communities studiedare remote, relatively small, multicultural, and dependent on natural resources. Thesalient dynamic illuminated in the research is how ideas of sustainability and neoliberalgovernance meet in community development. While the two governmentalities oftenconflict, they sometimes also complement one another, posing a paradox that raisesconcerns over the social aspect of sustainable development in particular. The articleis based on international, multidisciplinary research drawing on interviews as well asstatistical and documentary analysis
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