SHEAR WAVE ANISOTROPY MEASUREMENTS ABOVE SMALL EARTHQUAKES IN TRICHONIS LAKE, GREECE

On April 2007, an earthquake swarm occurred in the vicinity of Trichonis Lake, western Greece. The seismic activity started on April 10th, 2007 after the occurrence of three moderate size earthquakes Mw 5.0-5.2. We performed shear wave splitting measurements on seismic events recorded during the first week of the seismic activity by a portable network of 8 stations that was installed in the area by the University of Patras Seismological Laboratory. We were able to take measurements from 5 stations as the seismicity was concentrated mostly at the eastern part of the lake. Two splitting parameters were measured through the data processing, the time-delays between the fast and slow shear wave components and the polarization directions of the fast components. In general, the data analysis revealed the presence of shear wave anisotropy in the study area. The average value of normalized time-delays was calculated at 6.9 ±1.1 ms/km while the fast polarization directions had an average of 130 ±14 deg. The mean fast polarization directions were consistent with what is expected concerning the local stress field, as it was sub-parallel to the strike of the major faults at the eastern part of the lake and almost perpendicular to the direction of extension. Therefore, the findings can be interpreted by an anisotropic volume of stress-aligned micro-cracks within the upper crust according to the extensive dilatancy anisotropy model

Medical 3D printing: methods to standardize terminology and report trends.

BackgroundMedical 3D printing is expanding exponentially, with tremendous potential yet to be realized in nearly all facets of medicine. Unfortunately, multiple informal subdomain-specific isolated terminological 'silos' where disparate terminology is used for similar concepts are also arising as rapidly. It is imperative to formalize the foundational terminology at this early stage to facilitate future knowledge integration, collaborative research, and appropriate reimbursement. The purpose of this work is to develop objective, literature-based consensus-building methodology for the medical 3D printing domain to support expert consensus.ResultsWe first quantitatively survey the temporal, conceptual, and geographic diversity of all existing published applications within medical 3D printing literature and establish the existence of self-isolating research clusters. We then demonstrate an automated objective methodology to aid in establishing a terminological consensus for the field based on objective analysis of the existing literature. The resultant analysis provides a rich overview of the 3D printing literature, including publication statistics and trends globally, chronologically, technologically, and within each major medical discipline. The proposed methodology is used to objectively establish the dominance of the term "3D printing" to represent a collection of technologies that produce physical models in the medical setting. We demonstrate that specific domains do not use this term in line with objective consensus and call for its universal adoption.ConclusionOur methodology can be applied to the entirety of medical 3D printing literature to obtain a complete, validated, and objective set of recommended and synonymous definitions to aid expert bodies in building ontological consensus

Thyroid Hyalinizing Trabecular Tumor: A Case Series

Aim: Hyalinizing Trabecular Tumor (HTT) of the thyroid gland is an unusual and rare follicular derived neoplasm, which was first described from Carney and colleagues in 1987. We aim to present two cases of HTT diagnosed as papillary thyroid carcinomas in preoperative FNA cytological findings, although the postoperative histological examinations revealed the presence of Hyalinizing Trabecular tumors. Moreover, a short review regarding the diagnostic and clinical aspects of this rare thyroid tumor is also presented. Cases Presentation: A 30 year old and a 33 year old females were referred as having papillary thyroid carcinomas on preoperative FNA. Total thyroidectomy was offered in both. Histologic sections revealed the presence of HTT with the characteristic trabecular arrangement of polygonal/spindle cells and positive staining for MIB-1. Both patients remain disease free at a follow up of 5 years. Discussion: Although HTT diagnosis and differentiation from other thyroid tumors remains a topic of controversy, immunochemistry and molecular analysis may provide adequate information for HTT distinction from papillary thyroid carcinoma (PTC), medullary thyroid cancer (MTC) and paragaglioma. Therefore, suspicious cases based on preoperative FNA, require careful evaluation and cooperation of pathologists, endocrinologists and endocrine surgeons for optimal diagnosis and treatment. Conclusions: HTT is a rare, mostly benign neoplasm with favorable prognosis Preoperative identification of HTT is significant since its extremely low malignant potential and its favorable prognosis may lead to less extended operations and avoidance of postoperative radioiodine administration

Extreme ultraviolet lithography reaches 5 nm resolution

Extreme ultraviolet (EUV) lithography is the leading lithography technique in CMOS mass production, moving towards the sub-10 nm half-pitch (HP) regime with the ongoing development of the next generation high-numerical aperture (high-NA) EUV scanners. Hitherto, EUV interference lithography (EUV-IL) utilizing transmission gratings has been a powerful patterning tool for the early development of EUV resists and related processes, playing a key role in exploring and pushing the boundaries of photon-based lithography. However, achieving pattering with HPs well below 10 nm using this method presents significant challenges. In response, our study introduces a novel EUV-IL setup that employs mirror-based technology and circumvents the limitations of diffraction efficiency towards the diffraction limit that is inherent in conventional grating-based approaches. We present line/space patterning of HSQ resist down to HP 5 nm using the standard EUV wavelength 13.5 nm, and the compatibility of the tool with shorter wavelengths beyond EUV. The mirror-based interference lithography tool paves the way towards the ultimate photon-based resolution at EUV wavelengths and beyond. This advancement is vital for scientific and industrial research, addressing the increasingly challenging needs of nanoscience and technology and future technology nodes of CMOS manufacturing in the few-nanometer HP regime

Privacy Preserving Medical Data Analytics using Secure Multi Party Computation. An End-To-End Use Case.

Η νέα εποχή των μεγάλων δεδομένων απαιτεί μεγάλη υπολογιστική ισχύ, αφού το πλήθος των δεδομένων που δημοσιεύονται στο διαδίκτυο μεγαλώνει εκθετικά. Σαν αποτέλεσμα, προέκυψαν τα Νέφη Υπολογιστικών Συστημάτων, παρέχοντας μεγάλη υπολογιστική ισχύ, τόσο για ιδιώτες όσο και για επιχειρήσεις. Παρόλο που τα υπολογιστικά νέφη είναι η απάντηση σε πολλά επιχειρηματικά μοντέλα, υπάρχουν πολλές περιπτώσεις χρήσης όπου τα υπολογιστικά νέφη αποτυγχάνουν να καλύψουν τις απαιτήσεις ιδιωτικότητας των πληροφοριών. Για παράδειγμα, εκθέτοντας οικονομικές και ιατρικές πληροφορίας στο νέφος μπορεί να παραβιάζει το δικαίωμα των ατόμων στην ιδιωτικότητα. Οι άνθρωποι δεν νιώθουν άνετα με το να μοιράζονται τα ευαίσθητα δεδομένα τους, και πιο σημαντικά, δεν εμπιστεύονται κανέναν πάροχο υπολογιστικού νέφους με τις πληροφορίες αυτές. Τα δεδομένα που μεταφορτώνονται στο νέφος μπορεί να εκτεθούν σε επιθέσεις τόσο από τον πάροχο όσο και από τρίτους. Παρόλα αυτά, υπάρχουν πολλές πραγματικές περιπτώσεις χρήσης που χρησιμοποιούν πληροφορίες από διαφορετικές οντότητες προκειμένου να υπολογίσουν από κοινού ουσιαστικά αποτελέσματα, αλλά λόγω των προαναφερθέντων περιορισμών, κάποιες από αυτές αποφεύγονται και άλλες δεν σέβονται πάντα την ιδιωτικότητα των δεδομένων. Η λύση σε αυτό είναι μία τεχνική που ονομάζεται Ασφαλής Υπολογισμός Πολλαπλών Συμμετεχόντων, η οποία αξιοποιεί θεμελιώδεις κρυπτογραφικές ιδιότητες προκειμένου να εκτελέσει υπολογισμούς πάνω από εμπιστευτικά δεδομένα, υπολογίζοντας μία συνάρτηση και μαθαίνοντας τίποτε παραπάνω σε σχέση με το τι θα μάθαιναν N συμμετέχοντες, εάν μία ξεχωριστή έμπιστη οντότητα είχε συλλέξει τις εισόδους τους, είχε εκτελέσει την ίδια συνάρτηση, και τέλος επέστρεφε το αποτέλεσμα σε όλους τους συμμετέχοντες. Παίρνοντας κίνητρο από αυτό το ευρύ φάσμα εφαρμογών, στην εργασία αυτή επικεντρωθήκαμε στο να παρέχουμε μία ολοκληρωμένη υποδομή για υπολογισμό στατιστικών αναλύσεων με σεβασμό στην ιδιωτικότητα. Πιο συγκεκριμένα, έχουμε υλοποιήσει αλγορίθμους ειδικά σχεδιασμένους για κρυπτογραφημένες αρχιτεκτονικές, χρησιμοποιώντας το σενάριο του Ασφαλή Υπολογισμού Πολλαπλών Συμμετεχόντων, όπως ασφαλείς συγκεντρωτικούς αλγορίθμους και ασφαλείς κατηγοριοποιητές με δέντρα απόφασης. Ακόμα, συγκεντρωθήκαμε στο συντονισμό και την επικοινωνία μεταξύ όλων των συμμετεχόντων. Αυτών που παρέχουν δεδομένα, αυτών που εκτελούν τον ασφαλή υπολογισμό και τέλος αυτών που ξεκινούν νέους υπολογισμούς. Οι αλγόριθμοί μας δεν εξαρτώνται από την εφαρμογή που εξυπηρετεί το σύστημά μας, παρόλα αυτά, για λόγους παρουσίασης, στην εργασία αυτή χρησιμοποιούμε νοσοκομεία σας παρόχους δεδομένων και επικεντρωνόμαστε στην ιατρική έρευνα. Ο Στόχος μας είναι να ιδρύσουμε ένα ολοκληρωμένο σύστημα με σκοπό την ανακάλυψη χρήσιμης πληροφορίας με σεβασμό στην ιδιωτικότητα, και επίσης να προσφέρουμε τα δομικά στοιχεία για τυχόν πιο πολύπλοκους αλγορίθμους με σεβασμό στην ιδιωτικότητα.The new era of big data demands high performance computing, since the amount of data published online is growing exponentially. Cloud computing has emerged as a result, providing strong computational power for both individuals and companies. Though cloud computing is the answer to many business models, there are many use-cases where cloud fails to meet the demands of information privacy. For instance, exposing financial and medical information to the cloud may violate the individuals’ right to privacy. People are not comfortable sharing their sensitive data, and more importantly, they do not trust any cloud provider with this information; data that are uploaded in the cloud can be exposed to attacks from both the cloud provider and third parties. Nevertheless, there are many real world use cases that use information from different parties to jointly compute meaningful results, but due to the aforementioned limitations, some are avoided and others do not always respect data privacy. The solution to this is a technique called Secure Multi-Party Computation (SMPC or MPC), which leverages cryptographic primitives to carry out computations on confidential data, computing a function and learning nothing more than what the N parties would have if a separate trusted party had collected their inputs, computed the same function for them, and then return the result to all parties. Motivated by this wide range of applications, in this thesis we have focused on providing an end-to-end infrastructure for computing privacy-preserving analytics. More specifically, we have developed algorithms specifically tailored to encrypted architectures and in the SMPC scenario, such as secure aggregators and secure decision tree classifiers. Moreover, we have focused on the coordination and communication between all involved parties; those who provide their data, those who perform the secure computation, and finally those that initiate new computations. Our algorithms are not dependent to the application that our systems serves, however, in order to demonstrate it, in this thesis we use hospitals as data providers and we focus on medical research. Our goal is to establish an end-to-end system for discovering useful information with respect to data privacy, and also to provide the building blocks for potentially more elaborate privacy-preserving algorithms

Co-creating high-value hospitality services in the tourism ecosystem: Towards a paradigm shift?

Purpose: Adopting the service-ecosystem perspective, this is the first empirical study conceptualising tourism as an ecosystem. Based on the institutional theory and focusing on high-value hospitality services, it aims to unveil the components of the multilayer tourism ecosystem that enable stakeholders’ interactions at and between different levels. Methods: Applying a qualitative research design in Rhodes, the study focuses on value co-creation to explore the structure of the tourism ecosystem and its underlying mechanisms. Triangulation and bracketing were employed to ensure the reliability of the data collected through ten semi-structured interviews with high-ranking tourism policy-makers and hotel/restaurant managers. Results: The results led to the identification of the three-level service ecosystem (micro, meso, macro) that incorporates myriads of actions and interactions shaping tourism activity in order to provide high-value hospitality services. The analysis also revealed the institutional logic that permeates all levels (rules, norms, practices, meanings and symbols). Implications: The study goes beyond the destination-visitor and firm-guest interactions to incorporate multiple stakeholders co-creating value in the tourism ecosystem, including tourists, locals and employees, hotels and restaurants, DMOs and other organisations supporting the tourism value chain. It sheds light on the new paradigm shift from the notion of tourism industry to the concept of an inclusive tourism ecosystem, paving the way for future research to address global challenges in the COVID-19 era

Virtual reality and mental imagery towards travel inspiration and visit intention

The study examines the relationship between virtual reality (VR)-facilitated mental imagery and travellers' intention to visit a destination. A serial mediation process through travel inspiration (inspired-by and inspired-to) is proposed as a psychological mechanism able to explain the positive relationship of elaboration and quality of mental imagery with visit intentions. VR users were recruited through Prolific Academic. The findings demonstrate that VR-facilitated elaboration of mental imagery increases travel inspiration and consequently visit intention. However, the importance of mental imagery quality is much lower. The paper contributes to the literature of pre-travel VR experience by exploring the role of travel inspiration

3D printed ventricular septal defect patch: a primer for the 2015 Radiological Society of North America (RSNA) hands-on course in 3D printing.

Hand-held three dimensional models of the human anatomy and pathology, tailored-made protheses, and custom-designed implants can be derived from imaging modalities, most commonly Computed Tomography (CT). However, standard DICOM format images cannot be 3D printed; instead, additional image post-processing is required to transform the anatomy of interest into Standard Tessellation Language (STL) format is needed. This conversion, and the subsequent 3D printing of the STL file, requires a series of steps. Initial post-processing involves the segmentation-demarcation of the desired for 3D printing parts and creating of an initial STL file. Then, Computer Aided Design (CAD) software is used, particularly for wrapping, smoothing and trimming. Devices and implants that can also be 3D printed, can be designed using this software environment. The purpose of this article is to provide a tutorial on 3D Printing with the test case of complex congenital heart disease (CHD). While the infant was born with double outlet right ventricle (DORV), this hands-on guide to be featured at the 2015 annual meeting of the Radiological Society of North America Hands-on Course in 3D Printing focused on the additional finding of a ventricular septal defect (VSD). The process of segmenting the heart chambers and the great vessels will be followed by optimization of the model using CAD software. A virtual patch that accurately matches the patient's VSD will be designed and both models will be prepared for 3D printing

Numerical FEA parametric analysis of CAI behaviour of CFRP stiffened panels

This paper examined the effect of numerical modelling parameters on the accuracy and computational efficiency of Carbon Fibre Reinforced Polymer (CFRP) stiffened panels under Compression After Impact (CAI). Pristine and damaged CFRP stiffened panels were subjected to compression in Abaqus® software using Cohesive Zone Model (CZM) method. Various case studies were examined and the effect of the stiffness parameters of the cohesive elements was critically assessed. Moreover, the required number of cohesive zones to fully capture the damage mechanisms of the impacted and pristine panels under compressive loading was examined. The results showed that a wrong set of parameters can even lead to neglecting the induced damage and can cause severe convergence problems in the numerical model. The importance of the Overall Meshing Factor (OMF) was highlighted and a user-defined subroutine (USDFLD) was applied to capture the decrease in the load bearing capability of an impacted panel prior to the compressive loading, since CZM was found insufficient for this scope. The above-mentioned remarks illustrated the process of investigating the optimum numerical parameters set to achieve an accurate and efficient finite element modelling of the stiffened panels structural performance and maximum load-carrying capability, when subjected to CAI loading

Revascularization approaches in patients with radiation-induced carotid stenosis: an updated systematic review and meta-analysis

Background: Ionizing radiation remains a well-known risk factor of carotid artery stenosis. The survival rates of head and neck cancer patients undergoing radiotherapy have risen owing to medical advancements in the field. As a consequence, the incidence of carotid artery stenosis in these high-risk patients has increased.Aims: In this study we sought to compare the outcomes of carotid endarterectomy (CEA) vs carotid artery stenting (CAS) for radiation-induced carotid artery stenosis.Methods: This study was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Eligible studies were identified through a comprehensive search of PubMed, Scopus and Cochrane Central until July 2020. A random-effects model meta-analysis was conducted, and odds ratios (ORs) were calculated. The I-square statistic was used to assess for heterogeneity.Results: Seven studies and 201 patients were included. Periprocedural stroke, myocardial infarction (MI), and death rates were similar between the two revascularization approaches. However, the risk for cranial nerve (CN) injury was higher in the CEA group (OR, 7.40; 95% CI, 1.58–34.59; I2 = 0%). Analysis revealed no significant difference in terms of long-term mortality (OR, 0.41; 95% CI, 0.14–1.16; I2 = 0%) and restenosis rates (OR, 0.69; 95% CI, 0.29–1.66; I2 = 0%) between CEA and CAS after a mean follow-up of 40.5 months.Conclusions: CAS and CEA appear to have a similar safety and efficacy profile in patients with radiation-induced carotid artery stenosis. Patients treated with CEA have a higher risk for periprocedural CN injuries. Future prospective studies are warranted to validate these results