Graph Based Processing

Η παρούσα εργασία εξερευνεί την αρχιτεκτονική εξυπηρετητών. Μία ανάλυση διαφορετικών αρχιτεκτονικών σχεδιασμών αποκαλύπτει τους λόγους για τα διαφορετικά χαρακτηριστικά εκτέλεσης που αναδεικνύουν. Προτείνεται μία νεα αρχιτεκτονική, ο γράφος υπολογισμού (process graph), που στοχεύει να αποτελέσει ένα πλαίσιο ανάπτυξης υπηρεσιών και γενικευμένων υπολογισμών. Ο γράφος υπολογισμού, μαζί με πιθανές υλοποιήσεις του, στοχεύει στην αντιμετώπιση προβλημάτων επιδόσεων των υπαρχόντων αρχιτεκτονικών, καθώς και στη διευκόλυνση ανάπτυξης διαχειρίσιμων υπηρεσιών. Μέσω ανάλυσης και επαλήθευσης, υποστηρίζω ότι τα πιθανά πλεονεκτήματα που παρουσιάζονται ισχύουν και ότι ο γράφος υπολογισμού είναι ικανός να είναι ανταγωνιστικός με σύγχρονες αρχιτεκτονικές εξυπηρετητών.This thesis explores the software architecture of servers. An analysis of different architectural designs reveals the reasons for the different execution characteristics that they exhibit. A new computation abstraction is proposed, the process graph, that aims to be a framework to develop services and generic computations. The process graph, along with its potential implementations, aims to address performance problems with other architectures, as well as facilitate the easy development of maintainable services. Through analysis and evaluation, I argue that the potential benefits that are presented are valid and the process graph has the potential to be competitive with existing state of the art server architectures

Clinical epidemiology, treatment and prognostic factors of extensively drug-resistant Acinetobacter baumannii ventilator-associated pneumonia in critically ill patients

Limited data exist regarding prognostic factors and optimal antimicrobial treatment of infections caused by extensively drug-resistant Acinetobacter baumannii (XDR-AB). This retrospective cohort study included 93 adult patients who developed ventilator-associated pneumonia (VAP) due to XDR-AB in the ICU of the University Hospital of Heraklion, Greece, from October 2012 to April 2015. XDR-AB isolates were mainly susceptible to colistin (93.5%) and tigecycline (25.8%), whereas 6 (6.5%) were pandrug-resistant. Prior to infection, patients had long durations of mechanical ventilation and hospital stay and multiple exposures to antibiotics. Median Charlson co-morbidity and APACHE II scores were 2 and 17, respectively. Mortality at 28 days of infection onset was high (34.4%) despite high rates of in-vitro-active empirical (81.7%) and definitive (90.3%) treatment. Active colistin-based combination therapy (n = 55) and monotherapy (n = 29) groups had similar 28-day mortality (27.6% vs. 30.9%, respectively) and Kaplan–Meier survival estimates over time. In multivariable Cox regression, advanced age (aHR = 1.05 per year increase, 95% CI 1.02–1.09), rapidly fatal underlying disease (aHR = 2.64, 95% CI 0.98–9.17) and APACHE II score (aHR = 1.06 per unit increase, 95% CI 0.99–1.14) were identified as independent predictors of 28-day mortality, but no difference in mortality hazards between the active colistin-based combination therapy and monotherapy groups was produced (aHR = 0.88, 95% CI 0.35–2.38). These results support the use of colistin as a first-line agent against VAP in settings where XDR-AB is endemic, but oppose the introduction of colistin-based combination therapy as standard treatment

Chemical composition and source apportionment of the inorganic fraction of aerosol in Athens

The present study investigates the air pollution caused by airborne particles in the centre of Athens, Greece. The great scientific interest on airborne particles, or aerosols, is due to the numerous toxicological and epidemiological studies which have clearly demonstrated that aerosol pollution constitutes a potential hazard to citizens. Across the USA and EU, the number of deaths related to population exposure to high aerosol concentrations is estimated to range within tens to hundreds of thousands on an annual basis. As an atmospheric pollutant, airborne particles have been the subject of exhaustive research due to the vast variation in their physicochemical properties, which are dependent on their sources and production mechanisms. The scientific interest focuses particularly on the finer particle fractions, particularly the inhalable PM₁₀ and the respirable PM₂․₅. Despite the important number of studies carried out throughout the last decades, our knowledge on the aerosol pollution of Athens remains limited. Most studies have focused on a small number of pollutants, for sparse sampling periods and small sample sizes, while very few of them referred to the very centre of the city. These studies, in their entirety, as well as the governmental monitoring network have entailed aerosol sampling carried out at levels relatively high above ground. As a result, a detailed and systematic understanding of the aerosol pollution in the centre of the city, and particularly within the pedestrians’ “breathing zone” is still missing. The current study aims at determining the “fingerprint” of the aerosol pollution in the centre of Athens, by investigating the chemical composition of the inorganic fraction of aerosols. Moreover, this is attempted for sampling points within the pedestrians’ “breathing zone”, in order to provide knowledge of the pollution levels to which thousands of citizens are exposed on a daily basis. The spatial and seasonal variation of concentrations is examined both near the ground and on roof levels. Comparisons with older studies in Athens and other urban centres with similar characteristics area also attempted. Based on combined experimental data from independent sampling methods, the mean, bulk density of the PM₁₀ is estimated. Lastly, an advanced multivariate statistics method is implemented for the apportionment of inorganic aerosol mass to its major sources.Η παρούσα μελέτη αποσκοπεί στη διερεύνηση της αέριας ρύπανσης που προκαλείται από αιωρούμενα σωματίδια στο κέντρο της πόλης των Αθηνών. Το μεγάλο επιστημονικό ενδιαφέρον για τα αιωρούμενα σωματίδια οφείλεται στη διαπιστωμένη συσχέτισή τους, τόσο επιδημιολογικά όσο και τοξικολογικά, με σοβαρές επιπτώσεις στην ανθρώπινη υγεία. Συγκεκριμένα, υπολογίζονται σε αρκετές δεκάδες έως εκατοντάδες χιλιάδες ετησίως οι θάνατοι που σχετίζονται με την έκθεση σε αυξημένα επίπεδα σωματιδιακής ρύπανσης στις ΗΠΑ και την ΕΕ. Ως ρύπος, τα αιωρούμενα σωματίδια αποτελούν αντικείμενο εκτεταμένης έρευνας λόγω της ποικιλίας που εμφανίζουν οι χημικές και φυσικές τους ιδιότητες, αμφότερες συναρτήσεις των πηγών και των μηχανισμών σχηματισμού τους. Το επιστημονικό ενδιαφέρον επικεντρώνεται στα κλάσματα των λεπτότερων σωματιδίων και συγκεκριμένα τα εισπνεύσιμα PM₁₀, που μπορούν να φτάσουν έως και βαθιά εντός του ανθρώπινου αναπνευστικού συστήματος μέχρι και τους πνεύμονες και τα αναπνεύσιμα PM₂․₅ που μπορούν να εναποτεθούν στις κυψελίδες των πνευμόνων. Παρά το σημαντικό αριθμό σχετικών ερευνών που έχουν διενεργηθεί τις τελευταίες δεκαετίες, οι γνώσεις μας πάνω στην σωματιδιακή ρύπανση της Αθήνας εξακολουθούν να εμφανίζουν σοβαρές ελλείψεις. Οι περισσότερες μελέτες μέχρι σήμερα έχουν επικεντρωθεί σε ορισμένους μόνο ρύπους, για αραιές περιόδους δειγματοληψίας και με περιορισμένο αριθμό δειγμάτων, ενώ ελάχιστες είχαν ως σημείο αναφοράς το κέντρο της πόλης. Στο σύνολό τους, δε, οι εν λόγω μελέτες καθώς και η καθημερινή παρακολούθηση των επιπέδων ρύπανσης έχουν λάβει και λαμβάνουν χώρα σε σημεία δειγματοληψίας που βρίσκονται σε σημαντικό ύψος, έως και δεκάδων μέτρων, από το επίπεδο του εδάφους. Συνεπώς, εξακολουθεί να υπάρχει έλλειμμα συστηματικής και λεπτομερούς γνώσης για τη σωματιδιακή ρύπανση στο κέντρο της πόλης και ιδιαίτερα στη «ζώνη εισπνοής» των πεζών. Η παρούσα μελέτη στοχεύει στην λεπτομερή διερεύνηση της χημικής σύστασης του ανόργανου κλάσματος των αιωρουμένων σωματιδίων στο κέντρο της πόλης των Αθηνών, σε μια απόπειρα να προσδιοριστεί ένα είδος «δαχτυλικού αποτυπώματος» της σωματιδιακής ρύπανσης. Επιπλέον, επιδιώκεται να γίνει αυτό και εντός της «ζώνης εισπνοής» των πεζών, καταδεικνύοντας τα επίπεδα και τη σύσταση των σωματιδιακών συγκεντρώσεων στις οποίες εκτίθεται καθημερινά μεγάλος αριθμός πολιτών. Ταυτόχρονα, πραγματοποιούνται συγκρίσεις των συγκεντρώσεων και της χημικής σύστασης κοντά στο έδαφος και στην οροφή κτιρίου. Πραγματοποιούνται συγκρίσεις με παλαιότερες μελέτες στην Αθήνα καθώς και με αντίστοιχες μελέτες σε άλλα αστικά περιβάλλοντα διεθνώς και διερευνάται η εξέλιξη της ρύπανσης τις τελευταίες δύο δεκαετίες, ενώ εξετάζεται η εποχική διακύμανση των συγκεντρώσεων των επιμέρους χημικών παραγόντων. Επιπλέον, προσδιορίζεται προσεγγιστικά η μέση ολική πυκνότητα των PM₁₀. Τέλος, εφαρμόζεται προχωρημένη μέθοδος πολυμεταβλητής στατιστικής ανάλυσης για την ταυτοποίηση των κύριων πηγών που συνεισφέρουν στη μάζα του ανόργανου κλάσματος των αιωρούμενων σωματιδίων στο κέντρο της πόλης

Templated DSA vias in sub-7 nm circuits: Design strategy and DSA-aware via decomposition

status: publishe

Design Method for the Integration of DSA Via Patterning in sub-7 nm Circuits

status: publishe

Design method and algorithms for directed self-assembly aware via layout decomposition in sub-7 nm circuits

Major advancements in the directed self-assembly (DSA) of block copolymers have shown the technique’s strong potential for via/contact layer patterning in advanced technology nodes. Molecular scale pattern precision along with low cost processing promotes DSA technology as a great candidate for complementing conventional photolithography. Our studies show that decomposition of via layers with 193-nm immersion lithography in realistic circuits below the 7-nm node would require a prohibitive number of multiple patterning steps. The grouping of vias through templated DSA can resolve local conflicts in high density areas, limiting the number of required masks, and thus cutting a great deal of the associated costs. A design method for DSA via patterning in sub-7-nm nodes is discussed. We present options to expand the list of usable DSA templates and we formulate cost functions and algorithms for the optimal DSA-aware via layout decomposition. The proposed method works a posteriori, after place-and-route, allowing for fast practical implementation. We tested this method on a fully routed 32-bit processor designed for sub-7 nm technology nodes. Our results demonstrate a reduction of up to four lithography masks when compared to conventional non-DSA-aware decomposition.status: publishe

Design Strategy for Integrating DSA Via Patterning in sub-7 nm Interconnects

In recent years, major advancements have been made in the directed self-assembly (DSA) of block copolymers (BCPs). As a result, the insertion of DSA for IC fabrication is being actively considered for the sub-7 nm nodes. At these nodes the DSA technology could alleviate costs for multiple patterning and limit the number of lithography masks that would be required per metal layer. One of the most straightforward approaches for DSA implementation would be for via patterning through templated DSA, where via hole patterns are readily produced through templated confinement of cylindrical phase BCP materials. Our in-house studies show that decomposition of via layers in realistic circuits below the 7 nm node would require at least many multi-patterning steps (or colors), using 193 nm immersion lithography. Even the use of EUV might require double patterning in these dimensions, since the minimum via distance would be smaller than EUV resolution. The grouping of vial through templated DSA can resolve local conflicts in high density areas. This way, the number of required colors can be significantly reduced. To implement this approach, a DSA-aware mask decomposition is required. In this paper, a design method for DSA via patterning in sub-7 nm nodes is discussed. We present options to expand the list of DSA-compatible via patterns (DSA letters). Additionally, we define cost formulas and we develop a tool for the optimal DSA-aware layout decomposition. This method is tested on a fully routed processor, demonstrating a reduction of up to four lithography masks, when compared to conventional non-DSA-aware decomposition

BioFire (R) FilmArray (R) Pneumonia Panel for Severe Lower Respiratory Tract Infections: Subgroup Analysis of a Randomized Clinical Trial

Introduction: The epidemiology of severe lower respiratory tract infections (LRTI) is constantly changing. We aimed to describe it using the BioFire (R) FilmArray (R) Pneumonia plus (PNplus) Panel. Methods: In a sub-study of the PROGRESS trial, sputum samples of 90 patients with sepsis and LRTI were retrospectively studied. The primary endpoint was the comparative detection rate of pathogens between conventional microbiology and PNplus Panel; secondary endpoints were microbiology and the association with the inflammatory host response. Results: Fifty-six patients with community-acquired pneumonia without risk factors for multidrug-resistant (MDR) pathogens and another 34 patients with risk factors for MDR were studied; median pneumonia severity index (PSI) was 113 (88-135). PNplus detection rate was 72.2% compared to 10% by conventional microbiology (p < 0.001); Streptococcus pneumoniae was the most common pathogen. PSI and procalcitonin were greater among patients with bacterial pathogens than viral pathogens. Median procalcitonin was 0.49 ng/ml and 0.18 ng/ml among patients with >= 10(5) and < 10(5) copies/ml of detected bacteria, respectively (p = 0.004). Resistance reached 14.4%. Conclusion: PNplus detects severe pneumonia pathogens at a greater rate than conventional microbiology. High levels of inflammation accompany bacterial detection

Prevalence of Small Intestinal Bacterial Overgrowth Syndrome in Patients with Non-Alcoholic Fatty Liver Disease/Non-Alcoholic Steatohepatitis: A Cross-Sectional Study

Introduction: Non-alcoholic fatty liver disease (NAFLD) is a multifactorial, wide-spectrum liver disorder. Small intestinal bacterial overgrowth (SIBO) is characterized by an increase in the number and/or type of colonic bacteria in the upper gastrointestinal tract. SIBO, through energy salvage and induction of inflammation, may be a pathophysiological factor for NAFLD development and progression. Aim/Methods: Consecutive patients with histological, biochemical, or radiological diagnosis of any stage of NAFLD (non-alcoholic fatty liver [NAFL], non-alcoholic steatohepatitis [NASH], cirrhosis) underwent upper gastrointestinal endoscopy. Duodenal fluid (2cc) was aspirated from the 3rd–4th part of duodenum into sterile containers. SIBO was defined as ≥103 aerobic colony-forming units (CFU)/mL of duodenal aspirate and/or the presence of colonic-type bacteria. Patients without any liver disease undergoing gastroscopy due to gastroesophageal reflux disease (GERD) comprised the healthy control (HC) group. Concentrations (pg/mL) of tumor necrosis factor alpha (TNFα), interleukin (IL)-1β, and IL-6 were also measured in the duodenal fluid. The primary endpoint was to evaluate the prevalence of SIBO in NAFLD patients, while the comparison of SIBO prevalence among NAFLD patients and healthy controls was a secondary endpoint. Results: We enrolled 125 patients (51 NAFL, 27 NASH, 17 cirrhosis, and 30 HC) aged 54 ± 11.9 years and with a weight of 88.3 ± 19.6 kg (NAFLD vs. HC 90.7 ± 19.1 vs. 80.8 ± 19.6 kg, p = 0.02). Overall, SIBO was diagnosed in 23/125 (18.4%) patients, with Gram-negative bacteria being the predominant species (19/23; 82.6%). SIBO prevalence was higher in the NAFLD cohort compared to HC (22/95; 23.2% vs. 1/30; 3.3%, p = 0.014). Patients with NASH had higher SIBO prevalence (6/27; 22.2%) compared to NAFL individuals (8/51; 15.7%), but this difference did not reach statistical significance (p = 0.11). Patients with NASH-associated cirrhosis had a higher SIBO prevalence compared to patients with NAFL (8/17; 47.1% vs. 8/51; 15.7%, p = 0.02), while SIBO prevalence between patients with NASH-associated cirrhosis and NASH was not statistically different (8/17; 47.1% vs. 6/27; 22.2%, p = 0.11). Mean concentration of TNF-α, IL-1β, and IL-6 did not differ among the different groups. Conclusion: The prevalence of SIBO is significantly higher in a cohort of patients with NAFLD compared to healthy controls. Moreover, SIBO is more prevalent in patients with NASH-associated cirrhosis compared to patients with NAFL