10 research outputs found

    Late Alpine multistage exhumation of the northwestern Rhodope Metamorphic Complex (northern Rila Mountains, Bulgaria)

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    The Rhodope crystalline massif is an Alpine metamorphic complex exposed across several mountain ranges in southern Bulgaria and northern Greece which has experienced a complex history including continental collision, partial subduction and syn-metamorphic nappe stacking followed by syn- to post-contractional extension. We present new 40Ar/39Ar and fission-track data from samples taken from both sides of the North Rhodopean Detachment that were combined with detailed structural studies to investigate the tectonothermal evolution of the northern Rila Mountains. A migmatite from the hanging wall of the North Rhodopean Detachment yields a 40Ar/39Ar muscovite age of 100.79 ± 0.55 Ma, a zircon fission-track age of 38.6 ± 1.9 Ma, and an apatite fission-track age of 21.4 ± 1.5 Ma. A biotite schist from the footwall of the detachment yields 40Ar/39Ar biotite age of 34.90 ± 0.15 Ma, and zircon and apatite fission-track ages of 35.6 ± 5.6 and 13.3 ± 1.1 Ma, respectively. Our new data give evidence of a multistage exhumation of the study area. Late Early Cretaceous (~ 101 ± 0.6 Ma) cooling of the Variscan high-grade metamorphic basement through 440–400 °C was caused by either erosion of the emplacing thrust sheet, or post-contractional denudation. Fast exhumation along the North Rhodopean Extensional System drove a pulse of increased tectonic denudation and cooling during the Eocene (39–35 Ma). Exhumation of the rocks in the northern part of the Rila Mountains below 110 ± 10 °C during the middle–late Miocene was associated with displacement along a system of normal faults

    Evidence of Variscan and Alpine tectonics in the structural and thermochronological record of the central Serbo-Macedonian Massif (south-eastern Serbia)

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    The Serbo-Macedonian Massif (SMM) represents a composite crystalline belt within the Eastern European Alpine orogen, outcropping from the Pannonian basin in the north to the Aegean Sea in the south. The central parts of this massif (south-eastern Serbia) consist of the medium- to high-grade Lower Complex and the low-grade Vlasina Unit. Outcrop- and micro-scale ductile structures in this area document three major stages of ductile deformation. The earliest stage D1 is related to isoclinal folding, commonly preserved as up to decimetre-scale quartz–feldspar rootless fold hinges. D2 is associated with general south-eastward tectonic transport and refolding of earlier structures into recumbent metre- to kilometre-scale tight to isoclinal folds. Stages D1 and D2 could not be temporally separated and probably took place in close sequence. The age of these two ductile deformation stages was constrained to the Variscan orogeny based on indirect geological evidence (i.e. ca. 408-ca. 328). During this period, the SMM was involved in a transpressional amalgamation of the western and eastern parts of the Galatian super-terrane and subsequent collision with Laurussia. Outcrop-scale evidence of the final stage D3 is limited to spaced and crenulation cleavage, which are probably related to formation of large-scale open upright folds as reported previously. 40Ar/39Ar thermochronology was applied on hornblende, muscovite, and biotite samples in order to constrain the age of tectonothermal events and activity along major shear zones. These 40Ar/39Ar data reveal three major cooling episodes affecting the central SMM. Cooling below greenschist facies conditions in the western part of the Vlasina Unit took place in a post-orogenic setting (extensional or transtensional) in the early Permian (284 ± 1 Ma). The age of activity along the top-to-the-west shear zone formed within the orthogneiss in the Božica area of the Vlasina Unit was constrained to Middle Triassic (246 ± 1 Ma). This age coincides with widespread extension related to the opening of the Mesozoic Tethys. The greenschist facies retrogression in the Lower Complex probably occurred in the Early Jurassic (195 ± 1 Ma), and it was related to the thermal processes in the overriding plate above the subducting slab of the Mesozoic Tethys Ocean

    Pumpkin pulp extracts from a Serbian Cucurbita maxima Breeding Collection: Phenol profile and in vitro bioactivity

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    Methanolic pulp extracts from the four selected Serbian accessions of Cucurbita maxima were evaluated for phenol profile cytotoxic effects and antimicrobial activity. The results revealed that quinic acid and amentoflavone were the most abundant phenols. The extracts increased the viability of HTR-8 SV/Neo, JEG-3, JAR cells, with the most pronounced increase in the treatment with MAX 113 extract. Furthermore, in HeLa cells, the extracts showed a modest cytotoxic effect. The antimicrobial effects evaluation showed that out of four pumpkin extracts, MAX 117 could moderately suppress the growth of Staphylococcus aureus and Staphylococcus epidermidis (MIC=1000 µg/mL). The observed biological effects indicate the potential medicinal properties of these pumpkin extracts and contribute to the varietal selection of the most suitable accessions in national breeding programs as candidates for improving human health

    Design and preparation of proline, tryptophan and poly-l-lysine functionalized magnetic nanoparticles and their radiolabeling with 131I and 177Lu for potential theranostic use

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    Surface modification of magnetic nanoparticles with poly-L-lysine, proline, and tryptophan was used to design potential theranostic agents for the application in cancer diagnosis and radionuclide-hyperthermia therapy. Characterization of bare and functionalized magnetic nanoparticles was performed in detail. The transparency of the examined magnetic nanoparticles was measured in the non-alternating magnetic field for a complete and better understanding of hyperthermia. For the first time amino acid-functionalized magnetic nanoparticles were labeled with theranostic radionuclides 131I and 177Lu. The specific absorption rate (SAR) procured for poly-L-lysine functionalized magnetic nanoparticles (SAR values of 99.7 W/g at H0 = 15.9 kA/m and resonant frequency of 252 kHz) demonstrated their possible application in magnetic hyperthermia. Poly-L-lysine functionalized magnetic nanoparticles labeled with 177Lu showed the highest radiochemical purity (>99.00 %) and in vitro stability in saline and serum (>98.00 % up to 96 h). The in vivo analysis performed after their intravenous administration in healthy Wistar rats presented good in vivo stability for several days. Encouraging results as well as magnetic and radiochemical properties of 177Lu–PLL-MNPs (80 °C) justify their further testing toward the potential use as theranostic agents for diagnostic and combined radionuclide-hyperthermia therapeutic applications

    Color Doppler sonography and angioscintigraphy in hepatic Hodgkin’s lymphoma

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    AIM: To estimate the characteristics of Color Doppler findings and the results of hepatic radionuclide angiography (HRA) in secondary Hodgkin’s hepatic lymphoma

    Alpine thermal events in the central Serbo‑Macedonian Massif (southeastern Serbia)

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    The Serbo-Macedonian Massif (SMM) represents a crystalline belt situated between the two diverging branches of the Eastern Mediterranean Alpine orogenic system, the northeast-vergent Carpatho-Balkanides and the southwest-vergent Dinarides and the Hellenides. We have applied fission-track analysis on apatites and zircons, coupled with structural field observations in order to reveal the low-temperature evolution of the SMM. Additionally, the age and geochemistry of the Palaeogene igneous rocks (i.e. Surdulica granodiorite and dacitic volcanic rocks) were determined by the LA-ICPMS U–Pb geochronology of zircons and geochemical analysis of main and trace elements in whole-rock samples. Three major cooling stages have been distinguished from the late Early Cretaceous to the Oligocene. The first stage represents rapid cooling through the partial annealing zones of zircon and apatite (300–60 °C) during the late Early to early Late Cretaceous (ca. 110–ca. 90 Ma). It is related to a post-orogenic extension following the regional nappe-stacking event in the Early Cretaceous. Middle to late Eocene (ca. 48–ca. 39 Ma) cooling is related to the formation of the Crnook–Osogovo–Lisets extensional dome and its exhumation along low-angle normal faults. The third event is related to regional cooling following the late Eocene magmatic pulse. During this pulse, the areas surrounding the Surdulica granodiorite (36 ± 1 Ma) and the slightly younger volcanic bodies (ca. 35 Ma) have reached temperatures higher than the apatite closure temperature (120 °C) but lower than ca. 250 °C. The geochemistry of the igneous samples reveals late- to post-orogenic tectonic setting during magma generation

    Alpine thermal events in the central Serbo-Macedonian Massif (southeastern Serbia)

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