1,332 research outputs found

    On the paleogeographic distribution of the Late Maastrichtian planktonic foraminiferal genus Kassabiana SALAJSOLAKIUS, 1984

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    Representatives of the planktonic foraminiferal genus Kassabiana SALAJ & SOLAKIUS, 1984, are recorded in the uppermost Maastrichtian beds from the Parnassus-Ghiona and Pindus Zones, Greece. The new records have extended the known paleogeographic distribution of the species of Kassabiana in south Tethys northwards to the 30. N paleolatitude. The distribution was restricted to tropical waters since all the records of the species of Kassabiana are from areas which were situated at low latitudes during the Maastrichtian

    Investigating the Effect of Reaction Time on Carbon Dot Formation, Structure, and Optical Properties

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    Carbon dots, a young member of the carbon nanomaterial family, are quasi-spherical nanoparticles, which have fluorescent properties as their key characteristic. A wide range of starting materials and synthetic routes have been reported in the literature, divided into two main categories: a top-down and bottom-up approach. Moreover, a series of different parameters that affect the properties of carbon dots have been investigated, including temperature, starting pH, as well as precursor concentration. However, the effect of reaction time has not been extensively monitored. In our study, a biomass derivative was treated hydrothermally with varying reaction times to draw a solid formation mechanism. In addition, we monitored the effect of reaction time on optical and structural characteristics, as well as the chemical composition of our materials. Our key findings include a four-stage formation mechanism, a higher level of crystallinity, and an increasing brightness over reaction time

    MIOCENE SCLERACTINIAN CORALS OF GAVDOS ISLAND, SOUTHERN GREECE: IMPLICATIONS FOR TECTONIC CONTROL AND SEA-LEVEL CHANGES

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    Low-diversity scleractinian patch reefs that have been developed, during Early to Middle Tortonian, in Gavdos island are studied, aiming in a better understanding of the time and space relationships of the reef development and the associated basin fill evolution. Gavdos island consists part of a tectonically active setting constituting the southernmost extension of the Hellenic arc (Eastern Mediterranean). A representative Tortonian section (Bo section), located in the northwest part of the island, which hosts a mass occurrence of hermatypic corals, is studied. Scleractinian samples were collected from the upper 12 m of the section, which is characterized by interchanges of marly limestone and compact marls. The reefs are represented by the coral species Heliastraea oligophylla, Porites maicientensis, Thegioastraea roasendai and Porites collegniana. The microfacies analysis showed that the mediumto-thin-bedded carbonates of the limestone-marl alternations comprise patch reefs (boundstones-framestones, SMF 16, sensu Wilson, 1975, FZ 7-8, sensu Flügel 1982) consisted of screractinian corals. Corals are associated with corallinacean algae. Patch reefs are associated by bioclastic packstones-floatstones, characterized by benthic foraminifera, calcareous algae, spines of echinoids, gastropods and molluscs. Reefs are laterally associated by a bioclastic limestone rich in planktonic forams, associated by detrital material (fragments of quartz, feldspars, quartzites and cherts). The studied reef facies have been dolomitized and cemented in the meteoric realm. In places pseudomorphs after evaporites have been observed, tending to occlude cavities resulted after dissolution. The depositional environment corresponds to a moderate to high-energy inner platform setting, experiencing open-ocean influences. The pattern of coralgal reef development during Miocene, in the tectonically controlled Gavdos island, represents a complex interaction of tectonic activity and global sea-level changes

    Simulation of Crosstalk in High-Speed Multi-Chip Modules

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    Simulation results of the electrical performance at 1 GBits/sec of a number of different off-chip interconnection architectures are presented with emphasis given to the dependence of crosstalk and signal delay on the geometries and dielectric constants of the insulating layers as well as on the widths and separations of the conductors. The results indicate that signal delay and crosstalk may be reduced by using low εr values for the dielectrics and that crosstalk may be also reduced by reducing the conductor-to-ground wire separation which simultaneously neutralises the role of εr value on crosstalk and line impedance

    Red wine polyphenols modulate bone loss in the ovariectomized rat model of postmenopausal osteoporosis

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    Σκοπός αυτής της μελέτης ήταν να εξεταστεί η επίδραση του εκχυλίσματος πολυφαινολών του κόκκινου κρασιού (RWPs) στην οστική πυκνότητα (BMD) σε μοντέλο ωοθηκεκτομημένων επίμυων. Τριάντα πέντε Wistar επίμυες, ηλικίας 10 μηνών, χωρίστηκαν στις εξής ομάδες: ομάδα ελέγχου (CTRL), ωοθηκεκτομής (OVX) και την ομάδα ωοθηκεκτομής που έλαβε το εκχύλισμα RWPs (OVX+RWPs) σε συγκέντρωση 50 mg/kg σωματικού βάρους ανά ημέρα, ξεκινώντας αμέσως μετά από την ωοθηκεκτομή για 6 μήνες. Προσδιορίστηκε η οστική πυκνότητα πριν από οποιαδήποτε παρέμβαση, στους 3 και 6 μήνες. Οι επίμυες ευθανατώθηκαν και τα μηριαία οστά εξετάστηκαν με την δοκιμασία κάμψης τριών σημείων. Η σύγκριση των τιμών οστικής πυκνότητας ολόκληρης της κνήμης μεταξύ των ομάδων, ανέδειξε στατιστικά σημαντική μείωση στις ομάδες OVX και OVX+RWPs τόσο από την αρχική μέτρηση στους 3 και 6 μήνες, όσο και από τους 3 στους 6 μήνες, ενώ στην ομάδα CTRL δεν υπήρξε σημαντική αλλαγή. Η ποσοστιαία μεταβολή της οστικής πυκνότητας στην εγγύς μετάφυση της κνήμης από την αρχική μέτρηση στους 3 και 6 μήνες και από τους 3 στους 6 μήνες, αποκάλυψε στατιστικά σημαντικές διαφορές μεταξύ των ομάδων OVX και OVX + RWPs (P = 0.000). Η ωοθηκεκτομή προκάλεσε σημαντική μείωση των εμβιομηχανικών παραμέτρων όπως αναμενόταν, η δοκιμασία κάμψης τριών σημείων έδειξε ότι η μέγιστη φόρτιση πριν από τη θραύση, η απορρόφηση ενέργειας και η τάση θραύσης αυξήθηκε στατιστικά σημαντικά στην ομάδα OVX που υποβλήθηκε σε θεραπεία με RWPs σε σύγκριση με τους OVX επιμύες (P = 0.048, P = 0.002 και P = 0.003 αντίστοιχα). Η διατροφική πρόσληψη RWPs για 6 μήνες απέτρεψε την ταχεία οστική απώλεια και βελτίωσε την αντοχή των οστών σε ωοθηκεκτομημένους επίμυες.The aim of this study was to examine the effect of Red Wine Polyphenols (RWPs) extract on bone mineral density (BMD) in the ovariectomized (OVX) rat model. Thirty-five 10-month-old Wistar rats were separated into controls (CTRL), OVX and OVX plus RWPs in their drinking water (dose, 50 mg/kg body weight per day), starting immediately after OVX for 6 months. Βody and uterine weight, BMD of the tibia at baseline, 3 and 6 months post-OVX, and 3-pointing bending of the femur, were examined. Statistical comparison of the total tibia BMD within groups during the study period showed a significant reduction in the OVX and OVX+RWPs groups both from baseline to 3 and 6 months and from 3 to 6 months, whereas in the CTRL group, there was no significant change. For the proximal tibial metaphysis, comparison of BMD percentage changes from baseline to 3 months and 6 months and from 3 to 6 months revealed highly statistical differences between OVX and OVX+RWPs groups (P = 0.000). OVX induced a significant reduction of biomechanical parameters as expected; the 3-point bending test showed that the maximum force before fracture, energy absorption and fracture stress significantly increased in the OVX group treated with RWPs compared with the nontreated OVX rats (P = 0.048, P = 0.002 and P = 0.003, respectively). Dietary intake of RWPs for 6 months significantly prevented trabecular bone loss and improved bone strength in estrogen-deficient ovariectomized rats

    MAF functions as a pioneer transcription factor that initiates and sustains myelomagenesis

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    Deregulated expression of lineage-affiliated transcription factors (TFs) is a major mechanism of oncogenesis. However, how the deregulation of nonlineage affiliated TF affects chromatin to initiate oncogenic transcriptional programs is not well-known. To address this, we studied the chromatin effects imposed by oncogenic MAF as the cancer-initiating driver in the plasma cell cancer multiple myeloma. We found that the ectopically expressed MAF endows myeloma plasma cells with migratory and proliferative transcriptional potential. This potential is regulated by the activation of enhancers and superenhancers, previously inactive in healthy B cells and plasma cells, and the cooperation of MAF with the plasma cell-defining TF IRF4. Forced ectopic MAF expression confirms the de novo ability of oncogenic MAF to convert transcriptionally inert chromatin to active chromatin with the features of superenhancers, leading to the activation of the MAF-specific oncogenic transcriptome and the acquisition of cancer-related cellular phenotypes such as CCR1-dependent cell migration. These findings establish oncogenic MAF as a pioneer transcription factor that can initiate as well as sustain oncogenic transcriptomes and cancer phenotypes. However, despite its pioneer function, myeloma cells remain MAF-dependent, thus validating oncogenic MAF as a therapeutic target that would be able to circumvent the challenges of subsequent genetic diversification driving disease relapse and drug resistance
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