37 research outputs found

    Vertical Profiles of Aerosol Optical and Microphysical Properties During a Rare Case of Long-range Transport of Mixed Biomass Burning-polluted Dust Aerosols from the Russian Federation-kazakhstan to Athens, Greece

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    Multi-wavelength aerosol Raman lidar measurements with elastic depolarization at 532 nm were combined with sun photometry during the HYGRA-CD campaign over Athens, Greece, on May-June 2014. We retrieved the aerosol optical [3 aerosol backscatter profiles (baer) at 355-532-1064 nm, 2 aerosol extinction (aaer) profiles at 355-532 nm and the aerosol linear depolarization ratio (δ) at 532 nm] and microphysical properties [effective radius (reff), complex refractive index (m), single scattering albedo (ω)]. We present a case study of a long distance transport (~3.500-4.000 km) of biomass burning particles mixed with dust from the Russian Federation-Kazakhstan regions arriving over Athens on 21-23 May 2014 (1.7-3.5 km height). On 23 May, between 2-2.75 km we measured mean lidar ratios (LR) of 35 sr (355 nm) and 42 sr (532 nm), while the mean Ångström exponent (AE) aerosol backscatter-related values (355nm/532nm and 532nm/1064nm) were 2.05 and 1.22, respectively; the mean value of δ at 532 nm was measured to be 9%. For that day the retrieved mean aerosol microphysical properties at 2-2.75 km height were: reff=0.26 μm (fine mode), reff=2.15 μm (coarse mode), m=1.36+0.00024i, ω=0.999 (355 nm, fine mode), ω=0.992(355 nm, coarse mode), ω=0.997 (532 nm, fine mode), and ω=0.980 (532 nm, coarse mode)

    Flow field analysis of gas - liquid - solid three-phase flow in air-lift pumps

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    This PhD thesis deals with multiphase flows and air-lift pumps. All well-known theories concerning these two scientific fields are presented and analyzed in detail. Two computational codes were developed for homogeneous two-phase and separated three-phase flow. A comparison between theoretical results and experimental data followed. An experimental investigation was performed in a lab scale air-lift pump installation at Fluid Mechanics Laboratory, University of Patras. A new method for the precise prediction of the performance of a two-phase air-lift pump with the aid of drift-flux model was presented (CoSM method). New regime maps were introduced suitable for air-lift pump presentations. That means the direct view of the flow behaviour inside the air-lift pump, void fraction calculation and the regime transitions. An experimental method was presented for the prediction of slug-churn transition in two-phase flow, using a camera and ‘drift-flux’ model. The results of this work were presented in International Conferences and Journals.Με τη διατριβή έγινε ανασκόπηση των πιο γνωστών θεωριών που διέπουν τις πολυφασικές ροές. Ακολούθησε συλλογή και κριτική αξιολόγηση των θεωρητικών μοντέλων. Εκπονήθηκαν δύο προγράμματα σε Η/Υ, τόσο για την ομογενή ροή όσο και τη χωριστή ροή. Έγινε σύγκριση των θεωρητικών με υπάρχοντα πειραματικά αποτελέσματα. Σχεδιάστηκε και κατασκευάστηκε πειραματική διάταξη. Λήφθηκαν πειραματικές μετρήσεις και έγινε αξιολόγησή τους και σύγκριση με θεωρητικά αποτελέσματα. Προτάθηκε μέθοδος διόρθωσης της πρόβλεψης λειτουργίας μιας υδροπνευματικής αντλίας με τη βοήθεια του μοντέλου ‘drift-flux’ (μέθοδος CoSM). Προτάθηκαν νέοι ροϊκοί χάρτες κατάλληλοι για την παρουσίαση της λειτουργίας των υδροπνευματικών αντλιών, τον υπολογισμό του κλάσματος κενού και την μετάβαση των ροϊκών καταστάσεων. Προτάθηκε τρόπος προσδιορισμού της μετάβασης ‘slug-churn’ με απλή φωτογραφική μέθοδο (camera) και χρήση του μοντέλου ‘drift-flux’. Τα αποτελέσματα της διατριβής (πειράματα, μέθοδος CoSM, ροϊκοί χάρτες και μετάβαση slug-churn) παρουσιάστηκαν σε συνέδρια και επιστημονικά περιοδικά

    On the Properties of Adaptive Additive Increase

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    Is there any potential link among caspase-8, p-p38 MAPK and bcl-2 in clear cell renal cell carcinomas? A comparative immunohistochemical analysis with clinical connotations

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    Abstract Background Clear cell renal cell carcinomas (ccRCCs) constitute the most common renal carcinomas, characterized by a relatively aggressive clinical course. Thus, scientific research is targeting towards the identification of immunohistochemical and molecular markers that could be useful regarding diagnosis, appropriate therapy and prediction of prognosis. In the present study we assessed and correlated the expression of caspase-8, phosphorylated p38 mitogen-activated protein kinase (p-p38) and bcl-2 protein with histopathological features and clinical outcome of 27 patients with ccRCCs. Method Immunohistochemistry in formalin-fixed and paraffin-embedded tissue sections was performed. The associations among various features were assessed utilizing statistical analysis. Results We found that increased expression of cytoplasmic caspase-8 and bcl-2 protein was strongly associated with low Fuhrman's grade of carcinomas (p = 0.019 and p = 0.041, respectively). On the other hand, increased p-p38 expression was significantly related to high Fuhrman's grade (p = 0.006). Moreover, high bcl-2 expression was correlated with low pathological stage of ccRCCs (p = 0.026). Increased expression of cytoplasmic caspase-8 as well as low-grade tumors (grade 1 and 2) implied a greater probability of patients' survival, in univariate statistical analysis (p = 0.037 and p = 0.019, respectively). Neither p-p38 nor bcl-2 expression was significantly linked to patients' survival. There were not emerged statistically significant associations among caspase-8, p-p38 kinase and bcl-2 protein. Conclusion For the first time the prognostic impact of caspase-8 and p-p38 was studied in a series of ccRCCs, using immunohistochemistry in formalin-fixed and paraffin-embedded tissue sections. The suggestive relationship of caspase-8 with patients' clinical outcome, as well as the role of p-p38 within different grade categories, mandates further studies in larger cohorts of RCCs.</p

    Is there any potential link among caspase-8, p-p38 MAPK and bcl-2 in clear cell renal cell carcinomas? A comparative immunohistochemical analysis with clinical connotations

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    Background: Clear cell renal cell carcinomas (ccRCCs) constitute the most common renal carcinomas, characterized by a relatively aggressive clinical course. Thus, scientific research is targeting towards the identification of immunohistochemical and molecular markers that could be useful regarding diagnosis, appropriate therapy and prediction of prognosis. In the present study we assessed and correlated the expression of caspase-8, phosphorylated p38 mitogen-activated protein kinase (p-p38) and bcl-2 protein with histopathological features and clinical outcome of 27 patients with ccRCCs. Method: Immunohistochemistry in formalin-fixed and paraffin-embedded tissue sections was performed. The associations among various features were assessed utilizing statistical analysis. Results: We found that increased expression of cytoplasmic caspase-8 and bcl-2 protein was strongly associated with low Fuhrman’s grade of carcinomas (p = 0.019 and p = 0.041, respectively). On the other hand, increased p-p38 expression was significantly related to high Fuhrman’s grade (p = 0.006). Moreover, high bcl-2 expression was correlated with low pathological stage of ccRCCs (p = 0.026). Increased expression of cytoplasmic caspase-8 as well as low-grade tumors (grade 1 and 2) implied a greater probability of patients’ survival, in univariate statistical analysis (p = 0.037 and p = 0.019, respectively). Neither p-p38 nor bcl-2 expression was significantly linked to patients’ survival. There were not emerged statistically significant associations among caspase-8, p-p38 kinase and bcl-2 protein. Conclusion: For the first time the prognostic impact of caspase-8 and p-p38 was studied in a series of ccRCCs, using immunohistochemistry in formalin-fixed and paraffin-embedded tissue sections. The suggestive relationship of caspase-8 with patients’ clinical outcome, as well as the role of p-p38 within different grade categories, mandates further studies in larger cohorts of RCCs

    Small Extracellular Vesicles in Pre-Therapy Plasma Predict Clinical Outcome in Non-Small-Cell Lung Cancer Patients

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    The potential use of plasma-derived small extracellular vesicles (sEV) as predictors of response to therapy and clinical outcome in chemotherapy-naïve patients with non-small-cell lung cancer (NSCLC) was explored. sEV were isolated by size-exclusion chromatography from the plasma of 79 chemotherapy-naïve NSCLC patients and 12 healthy donors (HD). sEV were characterized with regard to protein content, particle size, counts by qNano, morphology by transmission electron microscopy, and molecular profiles by Western blots. PD-1 and PD-L1 expression on circulating immune cells was analysed by flow cytometry. Pre-treatment levels of total sEV protein (TEP) were correlated with overall (OS) and progression-free survival (PFS). The sEV numbers and protein levels were significantly elevated in the plasma of NSCLC patients compared to HD (p = 0.009 and 0.0001, respectively). Baseline TEP levels were higher in patients who developed progressive disease compared to patients with stable disease (p = 0.007 and 0.001, stage III and IV, respectively). Patient-derived sEV were enriched in immunosuppressive proteins as compared to proteins carried by sEV from HD. TEP levels were positively correlated with CD8+PD-1+ and CD8+PD-L1+ circulating T cell percentages and were independently associated with poorer PFS (p &lt; 0.00001) and OS (p &lt; 0.00001). Pre-therapy sEV could be useful as non-invasive biomarkers of response to therapy and clinical outcome in NSCLC

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    Synchronous well differentiated neuroendocrine tumour and gastrointestinal stromal tumour of the stomach: a case report

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    Abstract Background Well differentiated neuroendocrine tumours (carcinoids), arising from cells of the diffuse neuroendocrine system, represent the most commonly encountered gastric endocrine tumours. Gastrointestinal stromal tumours (GISTs), which stem from interstitial Cajal cells located within the wall of the gastrointestinal tract and have a characteristic immunoreactivity for CD117 (c-kit protein), account for the majority of gastrointestinal mesenchymal neoplasms. Simultaneous occurrence of a GIST with a well differentiated neuroendocrine tumour in the stomach is very rare. Methods Clinical history, endoscopy and histopathological findings were utilized for our diagnostic considerations. Results We report the coexistence of a high risk GIST with a well differentiated neuroendocrine tumour of benign clinical behavior, both located in the stomach, in a 62-year-old man previously operated for a gastric well differentiated neuroendocrine tumour with uncertain malignant behaviour. Conclusions Even single well differentiated, sporadic, NETs of small size may coexist with GISTs. An appropriate initial therapeutic approach combined with a scrupulous follow-up seems to play a significant role in terms of preventing a metastatic disease.</p
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