Novel conducting polymer current limiting devices for low cost surge protection applications

We report on the development of novel intrinsic conducting polymer two terminal surge protection devices. These resettable current limiting devices consist of polyaniline nanofibres doped with methane sulphonic acid electrochemically deposited between two 55 μm spaced gold electrodes. At normal applied voltages, the low resistance devices act as passive circuit elements, not affecting the current flow. However during a current surge the devices switch from ohmic to non-ohmic behaviour, limiting current through the device. After the current surge has passed, the devices reset back to their original state. Our studies show that a partial de-doping/re-doping process caused by the rapid diffusion of moisture out of or into the polymer film during joule heating/cooling is the underlying mechanism responsible

Μελέτες πολυμεταβλητών αναλυτών με πραγματικά δεδομένα και δεδομένα προσομοίωσης για την διαδικασία ttH, H->bbbar στο διλεπτονικό κανάλι με το πείραμα CMS στον LHC του CERN

Ο Μεγάλος Επιταχυντής Αδρονίων LHC (Large Hadron Collider στο Εργαστήριο CERN παρέχει συγκρούσεις πρωτονίου-πρωτονίου στα 13 TeV η υψηλότερη ενέργεια μέχρι σήμερα, καθιστώντας τα πειράματα ικανά να ελέγξουν και να διερευνήσουν το Καθιερωμένο Πρότυπο (ΚΠ) με μεγάλη ακρίβεια. Η ανακάλυψη του μποζονίου Higgs (4 Ιουλίου 2012) επιβεβαίωσε την ύπαρξη μηχανισμού, ο οποίος προσδίδει μάζα στα σωμάτια. Η σταθερά σύζευξης του σωματίου Higgs με τα φερμιόνια, που είναι ανάλογη της μάζας του φερμιονίου, μας προτρέπει να μελετήσουμε την σύζευξή του με το βαρύτερο φερμιόνιο του ΚΠ, το top quark. Στην παρούσα εργασία γίνεται η μελέτη παραγωγής του Higgs μαζί με ζεύγος top quark - antiquark (ttH), με το Higgs να διασπάται τελικώς σε ζεύγος bbbar και τα top quarks να διασπώνται λεπτονικά. Σκοπός της εργασίας είναι η αύξηση της σημαντικότητας ταυτοποίησης των γεγονότων σήματος απο το αναμενόμενο υπόβαθρο. Γίνεται ανασκόπηση της μεθόδου "Ρυθμός ταυτοποίησης b-καταιγισμών" (Tag Rate Function) για την πρόβλεψη του κύριου υποβάθρου ttbar + jets, με τη χρήση των πραγματικών δεδομένων (Data driven). Έπειτα επαληθεύεται η μέθοδος στα πραγματικά δεδομένα, καθώς και η συμφωνία μεταξύ πραγματικών και δεδομένων προσομοίωσης. Τέλος αναπτύσσεται ένα νεο Νευρωνικό Δίκτυο (Artificial Neural Network), το οποίο θα χρησιμοποιηθεί σαν επιπλέον κριτήριο διαχωρισμού του σήματος απο το υπόβαθρο και αυξάνει κατά πολύ την σημαντικότητα της μέτρησης. Η εκπαίδευση του νευρωνικού δικτύου γίνεται με εμπλουτισμένη στατιστική δεδομένων, χρησιμοποιώντας τα βάρη που παράγονται απο την μέθοδο TRF. Τέλος η αναμενόμενη απόδοση της ανάλυσης με δεδομένα από το εγγύς (Run III) αλλά και απώτερο (HL-LHC) παρουσιάζεται εν συντομία.The Large Hadron Collider (LHC) at the CERN laboratory provides proton-proton collisions at 13 TeV, the highest energy to date, enabling experiments to investigate the Standard Model of physics (SM) with great accuracy. The discovery of the Higgs boson (July 4, 2012) confirmed the existence of a mechanism that gives mass to particles. The coupling constant of the Higgs' particle with fermions, which is proportional to the mass of the fermion, prompts us to study its coupling with the heaviest fermion of SM, the top quark. In the present work, the associated production of Higgs boson with a top quark - antiquark pair (ttH), with Higgs finally decaying into a bbbar pair and both top quarks decaying into leptons, is being studied. The purpose of this work is the improvement in the significance of the measurements, namely the detection of the signal over the expected background. The "Tag Rate Function" (TRF) method of a data driven prediction for the main ttbar + jets background, namely TRF, is being reviewed. The method is then verified in the real datasets, and the agreement between real and simulation data is also examined. Finally, a new Artificial Neural Network is developed, which can be used as an additional pre-selection criterion for the signal separation over the background and increases the significance of the measurement by a large factor. The Neural Network's training occurs via enriched data statistics, applying the weights produced by the TRF method. Finally the performance of the overall analysis in the near (Run III) and longer term (HL-LHC) future is being briefly presented

Super hydrophobic SAM modified electrodes for enhanced current limiting properties in intrinsic conducting polymer surge protection devices

Surface interface engineering using superhydrophobic gold electrodes made with 1-dodecanethiol self-assembled monolayer (SAM) has been used to enhance the current limiting properties of novel surge protection devices based on the intrinsic conducting polymer, polyaniline doped with methanesulfonic acid. The resulting devices show significantly enhanced current limiting characteristics, including current saturation, foldback, and negative differential effects. We show how SAM modification changes the morphology of the polymer film directly adjacent to the electrodes, leading to the formation of an interfacial compact thin film that lowers the contact resistance at the Au−polymer interface. We attribute the enhanced current limiting properties of the devices to a combination of lower contact resistance and increased Joule heating within this interface region which during a current surge produces a current blocking resistive barrier due to a thermally induced dedoping effect caused by the rapid diffusion of moisture away from this region. The effect is exacerbated at higher applied voltages as the higher temperature leads to stronger depletion of charge carriers in this region, resulting in a negative differential resistance effec

Regional variation in the productivity of the English national health service

Variation in the provision of health care has long been a policy concern. We adapt the framework for productivity measurement used in the National Accounts, making it applicable for sub-national comparisons using cross-sectional data. We assess the productivity of the National Health Service (NHS) across regions of England, termed Strategic Health Authorities (SHAs). Productivity is calculated by comparing the total amount of healthcare output to total inputs for each region, standardised to the national average. Healthcare output comprises 6500 different categories, capturing the number and type of NHS patients treated and the quality of care received. Healthcare inputs include NHS and agency staff, supplies, equipment and capital. We find that productivity varies from 5% above to 6% below the national average. Productivity is highest in South West SHA and lowest in East Midlands, South Central and Yorkshire and The Humber SHAs. We estimate that if all regions were as productive as the most productive region in England, the NHS could treat the same number of patients with £3.2bn fewer resources each year. The methods developed lend themselves to investigate variations in productivity in other types of healthcare organisations and health systems

Comparison of Bacterial Community Composition of Primary and Persistent Endodontic Infections Using Pyrosequencing

Elucidating the microbial ecology of endodontic infections (EI) is a necessary step in developing effective intra-canal antimicrobials. The aim of the present study was to investigate the bacterial composition of symptomatic and asymptomatic primary and persistent infections in a Greek population, using high throughput sequencing methods

Periodontitis and Cardiovascular Diseases. Consensus Report

Background: In Europe cardiovascular disease (CVD) is responsible for 3.9 million deaths (45% of deaths), being ischaemic heart disease, stroke, hypertension (leading to heart failure) the major cause of these CVD related deaths. Periodontitis is also a chronic non-communicable disease (NCD) with a high prevalence, being severe periodontitis, affecting 11.2% of the world's population, the sixth most common human disease. Material and Methods: There is now a significant body of evidence to support independent associations between severe periodontitis and several NCDs, in particular CVD. In 2012 a joint workshop was held between the European Federation of Periodontology (EFP) and the American Academy of Periodontology to review the literature relating periodontitis and systemic diseases, including CVD. In the last five years important new scientific information has emerged providing important emerging evidence to support these associations. Results and Conclusions: The present review reports the proceedings of the workshop jointly organised by the EFP and the World Heart Federation (WHF), which has updated the existing epidemiological evidence for significant associations between periodontitis and CVD, the mechanistic links and the impact of periodontal therapy on cardiovascular and surrogate outcomes. This review has also focused on the potential risk and complications of periodontal therapy in patients on anti thrombotic therapy and has made recommendations for dentists, physicians and for patients visiting both the dental and medical practices

Periodontitis and Cardiovascular Diseases. Consensus Report.

Background: In Europe cardiovascular disease (CVD) is responsible for 3.9 million deaths (45% of deaths), being ischaemic heart disease, stroke, hypertension (leading to heart failure) the major cause of these CVD related deaths. Periodontitis is also a chronic non-communicable disease (NCD) with a high prevalence, being severe periodontitis, affecting 11.2% of the world's population, the sixth most common human disease. Material and Methods: There is now a significant body of evidence to support independent associations between severe periodontitis and several NCDs, in particular CVD. In 2012 a joint workshop was held between the European Federation of Periodontology (EFP) and the American Academy of Periodontology to review the literature relating periodontitis and systemic diseases, including CVD. In the last five years important new scientific information has emerged providing important emerging evidence to support these associations. Results and Conclusions: The present review reports the proceedings of the workshop jointly organised by the EFP and the World Heart Federation (WHF), which has updated the existing epidemiological evidence for significant associations between periodontitis and CVD, the mechanistic links and the impact of periodontal therapy on cardiovascular and surrogate outcomes. This review has also focused on the potential risk and complications of periodontal therapy in patients on anti thrombotic therapy and has made recommendations for dentists, physicians and for patients visiting both the dental and medical practices

Perception and beliefs about mental illness among adults in Karfi village, northern Nigeria

BACKGROUND: This study was designed to examine the knowledge, attitude and beliefs about causes, manifestations and treatment of mental illness among adults in a rural community in northern Nigeria. METHODS: A cross sectional study design was used. A pre-tested, semi-structured questionnaire was administered to 250 adults residing in Karfi village, northern Nigeria. RESULTS: The most common symptoms proffered by respondents as manifestations of mental illness included aggression/destructiveness (22.0%), loquaciousness (21.2%), eccentric behavior (16.1%) and wandering (13.3%). Drug misuse including alcohol, cannabis, and other street drugs was identified in 34.3% of the responses as a major cause of mental illness, followed by divine wrath/ God's will (19%), and magic/spirit possession (18.0%). About 46% of respondents preferred orthodox medical care for the mentally sick while 34% were more inclined to spiritual healing. Almost half of the respondents harbored negative feelings towards the mentally ill. Literate respondents were seven times more likely to exhibit positive feelings towards the mentally ill as compared to non-literate subjects (OR = 7.6, 95% confidence interval = 3.8–15.1). CONCLUSIONS: Our study demonstrates the need for community educational programs in Nigeria aimed at demystifying mental illness. A better understanding of mental disorders among the public would allay fear and mistrust about mentally ill persons in the community as well as lessen stigmatization towards such persons