320 research outputs found

    LASER μ-RAMAN INVESTIGATION OF GREEK BAUXITES FROM THE PARNASSOS-GHIONA ACTIVE MINING AREA

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    Δείγματα βωξίτη τα οποία αποκτήθηκαν από εταιρείες που εμφανίζουν ενεργή μεταλλευτική δραστηριότητα στην περιοχή Παρνασσού-Γκιώνας χαρακτηρίσθηκαν αρχικά με τη χρήση συμβατικών μεθόδων (οπτικό μικροσκόπιο, περίθλαση ακτινών Χ) και στη συνέχεια μελετήθηκαν χρησιμοποιώντας, για πρώτη φορά στη διεθνή βιβλιογραφία, προηγμένες μή-καταστροφικές φασματοσκοπικές τεχνικές σε μικροκλίμακα (Laser μ-Raman). Τα αποτελέσματα της παρούσας μελέτης έδειξαν πως ο τύπος του βωξίτη (διασπορικός ή μπαιμιτικός) μπορεί εύκολα να προσδιοριστεί, ανεξάρτητα από το είδος του δείγματος (πορώδες ^κό-τεφρό ή και συμπαγές ερυθρό-φαιό), μέσω της καταγραφής του φάσματος του στην περιοχή χαμηλών ενεργειών (250 cm' - 600 cm'1) όπου και είναι ευδιάκριτες συγκεκριμένες Raman ταινίες των πολύμορφων του ΑΙΟΟΗ (448 cm' για το διάσπορο και 362 cm'1 για τον μπαιμίτη). Η παραπάνω μικρο-μέθοδος θα μπορούσε να εφαρμοσθεί για τον άμεσο προσδιορισμό των ορυκτολογικών φάσεων τόσο στο εργαστήριο όσο και επιτόπου στα μεταλλεία, έτσι ώστε να αποφευχθούν έμμεσες και χρονοβόρες ολικές τεχνικές οι οποίες χρησιμοποιούνται έως και σήμερα (όπως π.χ. η περίθλαση ακτινών Χ).Bauxite samples collected with permission from currently active mining areas in the Parnassos-Ghiona Mts district were studied using both conventional (optical microscopy and powder XRD) and, for the first time in the literature, micro-scale advanced non-destructive spectroscopic techniques, in particular Laser μ-Raman. The results showed that the different bauxite types (diasporic or boehmitic) can easily be identified regardless of sample type (porous white-grey or massive redbrown) by recording spectra in the low-wavenumber region (250 cm' - 600 cm' ) where distinct bands of the natural AlOOHpolymorphs are easily discernible (448 cm' for diaspore and 362 cm' for boehmite). The method described herein could equally be applied in the laboratory as well as in-situ at the mines for quick and accurate phase determination, in order to bypass the laborious and time-consuming indirect bulk techniques (such as XRD) routinely used to this date

    Arachnoid cysts: the role of the BLADE technique

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    Background: This study aims at demonstrating the ability of BLADE sequences to reduce or even eliminate all the image artifacts as well as verifying the significance of using this technique in certain pathological conditions

    Boosting mobility performance with multi-path TCP

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    Proceeding of: Future Network & Mobile Summit 2010, 16 - 18 June 2010, Florence, ItalyFourth Generation mobile devices incorporate multiple interfaces with diverse access technologies. The current Mobile IP protocol fails to support the enhanced fault tolerance capabilities that are enabled by the availability of multiple interfaces. In particular, established Mobile IP communications cannot be preserved through outages affecting the Home Address. In this paper we describe an architecture for mobile host multihoming that enables transport layer survivability through multiple failure modes. The proposed approach relies on the cooperation between Mobile IP and Multi-Path TCP and aims to fully support multihoming and extend roaming capabilities of mobile devices.This research was supported by Trilogy (http://www.trilogy-project.org), a research project (ICT-216372) partially funded by the European Community under its Seventh Framework Programme.European Community's Seventh Framework ProgramNo publicad

    Application of Electrical Resistivity Tomography to the detection of the Ermakia (Northern Greece) cavity system

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    Η μέθοδος της Ηλεκτρικής Τομογραφίας εφαρμόστηκε για την εξερεύνηση ενός καρστικού σπηλαίου στην περιοχή της Ερμακίας (Μ. Πτολεμαίδας). Οι γεωλογικές έρευνες έδειξαν ότι η γνωστή κεντρική αίθουσα του σπηλαίου της Ερμακιάς "επικοινωνεί" με τουλάχιστον έναν υπόγειο καρστικό έγκοιλο. Αυτά τα στοιχεία μας οδήγησαν στη διερεύνηση της περιβάλλουσας περιοχής με την εφαρμογή δισδιάστατης ηλεκτρικών τομογραφιών σε ένα πυκνό πλέγμα μετρήσεων σε δυο κάθετες διευθύνσεις. Κάποιες από τις γραμμές έρευνας τοποθετήθηκαν πάνω από το χαρτογραφημένο τμήμα του σπηλαίου ώστε να βεβαιωθεί η καταλληλότητα της μεθόδου και να επιτευχθεί βαθμονόμηση των τιμών της ειδικής ηλεκτρικής αντίστασης. Τα αποτελέσματα της αντιστροφής των γεωηλεκτρικών δεδομένων συνδυάστηκαν ώστε να παραχθούν ψευδοτρισδιάστατες εικόνες της αντίστασης. Η ερμηνεία των αποτελεσμάτων είχε ως αποτέλεσμα να εντοπιστούν νέοι θάλαμοι του σπηλαίου όπως επιβεβαιώνεται και από γεωλογικές παρατηρήσεις στο σπήλαιο.Electrical resistivity tomography has been applied for the exploration of a karstic cave system at the region of Ermakia, next to the city of Ptolemais (NWt Greece). Geological investigations indicated that the main known Ermakia cave chamber "communicates " with at least one underground karstic ovoid. This evidence lead us to prospect the surrounding area by applying 2-D Electrical tomography survey on a regular grid in both x,y directions. Survey lines crossed the known cave in order to verify k the suitability of the method at the specific area and calibrate the resistivity values. Resistivity data were inverted and results were compiled in qusi3-D resistivity images. The interpreted results indicated the existence of two more chambers next to the known one which is in agreement with in-situ observations

    Circulating Tissue Inhibitor of Matrix Metalloproteinase-4 (TIMP-4) in Systemic Sclerosis Patients with Elevated Pulmonary Arterial Pressure

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    Decreased levels of matrix metalloproteinases (MMPs) or excess levels of their tissue inhibitors (TIMPs) may contribute to dysregulation of extracellular matrix turnover in systemic sclerosis (SSc). In a cross-sectional study of 106 SSc patients, we measured serum levels of TIMP-4 which is preferentially expressed in cardiovascular structures and searched for correlations with simultaneously performed echocardiography measurements of pulmonary artery systolic pressure (PASP), myocardial performance, and pulmonary function tests. TIMP-4, but not MMP-9, levels were significantly raised in patients with SSc than controls. However, in the subgroup of patients with PASP measurements lower to 40 mmHg (n = 69), TIMP-4 levels were comparable to controls irrespective of the presence of diffuse or limited skin involvement, or lung fibrosis. Individual PASP measurements suggestive of pulmonary hypertension were associated with increased TIMP-4 serum levels (P = .03), independently of age, extent of skin sclerosis, or lung fibrosis, suggesting a cardiopulmonary vasculature-specific role of TIMP-4 activation in SSc

    The innate sensor ZBP1-IRF3 axis regulates cell proliferation in multiple myeloma

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    Multiple myeloma is a malignancy of plasma cells (PC) initiated and driven by primary and secondary genetic events. Nevertheless, myeloma PC survival and proliferation might be sustained by non-genetic drivers. Z-DNA-binding protein 1 (ZBP1; also known as DAI) is an interferon-inducible, Z-nucleic acid sensor that triggers RIPK3-MLKL-mediated necroptosis in mice. ZBP1 also interacts with TBK1 and the transcription factor IRF3 but the function of this interaction is unclear, and the role of ZBP1-IRF3 axis in cancer is not known. Here we show that ZBP1 is selectively expressed in late B cell development in both human and mouse cells and it is required for optimal T-cell-dependent humoral immune responses. In myeloma PC, interaction of constitutively expressed ZBP1 with TBK1 and IRF3 results in IRF3 phosphorylation. IRF3 directly binds and activates cell cycle genes, in part through co-operation with the PC lineage-defining transcription factor IRF4, and thereby promoting myeloma cell proliferation. This generates a novel, potentially therapeutically targetable and relatively selective myeloma cell addiction to the ZBP1-IRF3 axis. Our data also show a non-canonical function of constitutive ZBP1 in human cells and expand our knowledge of the role of cellular immune sensors in cancer biology
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