Development of multilayer Hydroxyapatite - Ag/TiN-Ti coatings deposited by radio frequency magnetron sputtering with potential application in the biomedical field

"NOTICE: this is the author's version of a work that was accepted for publication in Surface and Coatings Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Surface and Coatings Technology, VOL 377, (2019) DOI 10.1016/j.surfcoat.2019.06.097"[EN] The use of composite coatings is emerging as a great alternative to conventional coatings, allowing the combination of different superficial properties that are widely desired in surgical implants, such as osteointegration and bactericidal character, and cannot be provided by one material alone. In the present investigation the effect of the incorporation of a TiN-Ti intermediate bilayer on the chemical composition, structure, morphology, roughness, residual stresses and adhesion of a multi-layer Hydroxyapatite (HA)-Ag coating deposited on Ti-6Al-4V by magnetron sputtering was evaluated. Additionally, the cytotoxicity of the developed system was evaluated by in vitro tests. According to the results obtained, a decrease in the Ca/P ratio from 1.85 to 1.74 was obtained through the deposition of an HA-Ag system on the intermediate bilayer, and the crystallinity of the developed coating was favored. The multi-layer structure was effectively observed by field emission scanning electron microscopy, where it was possible to identify each of the HA, Ag, TiN and Ti layers. Meanwhile, an increase of 7% in crystallite size, a decrease of 36% in residual stresses and an increase of 32% in adhesion were registered for this composite coating compared to the free intermediate bilayer system. Finally, biological evaluation allowed the non-cytotoxic character of the deposited coatings to be confirmed.We thank the University of Antioquia, the Centro de Investigation, Innovation y Desarrollo de materiales (CIDEMAT) group, the Departamento Administrativo de Ciencia, Tecnologia e Innovation (COLCIENCIAS) for financing the Project 15-1696, the scholarship program of Enlazamundos, PR and JLGR acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-1-R (AEI/FEDER, UE) (including the FEDER financial support). CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER Actions are financed by the Institute de Salud Carlos III with assistance from the European Regional Development Fund.Lenis, J.; Bejarano, G.; Rico Tortosa, PM.; Gómez Ribelles, JL.; Bolívar, F. (2019). Development of multilayer Hydroxyapatite - Ag/TiN-Ti coatings deposited by radio frequency magnetron sputtering with potential application in the biomedical field. Surface and Coatings Technology. 377:1-9. https://doi.org/10.1016/j.surfcoat.2019.06.097S19377Melero, H., Fernández, J., & Guilemany Casadamon, J. M. (2011). Recubrimientos bioactivos: Hidroxiapatita y titania. Biomecánica, 19(1). doi:10.5821/sibb.v19i1.1814Ozeki, K., Yuhta, T., Fukui, Y., & Aoki, H. (2002). Phase composition of sputtered films from a hydroxyapatite target. Surface and Coatings Technology, 160(1), 54-61. doi:10.1016/s0257-8972(02)00363-8Nelea, V., Morosanu, C., Iliescu, M., & Mihailescu, I. N. (2003). 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Syntheses of hydroxyapatite from natural sources

Waste materials from natural sources are important resources for extraction and recovery of valuable compounds. Transformation of these waste materials into valuable materials requires specific techniques and approaches. Hydroxyapatite (HAp) is a biomaterial that can be extracted from natural wastes. HAp has been widely used in biomedical applications owing to its excellent bioactivity, high biocompatibility, and excellent osteoconduction characteristics. Thus, HAp is gaining prominence for applications as orthopaedic implants and dental materials. This review summarizes some of the recent methods for extraction of HAp from natural sources including mammalian, aquatic or marine sources, shell sources, plants and algae, and from mineral sources. The extraction methods used to obtain hydroxyapatite are also described. The effect of extraction process and natural waste source on the critical properties of the HAp such as Ca/P ratio, crystallinity and phase assemblage, particle sizes, and morphology are discussed herein

The Life-World of Moslem Women in Freiburg

Das Erschließen der islamischen Glaubenswelt kann am besten in der persönlichen Begegnung mit muslimischen Gläubigen erfolgen. Demzufolge geben die qualitativ angelegten Interviews dieser Studie einen Einblick in die Lebenswelten muslimischer Frauen aus Freiburg, beleuchten deren Religiosität und die daraus entstandenen Lebensentwürfe. Diese Untersuchung ergab, dass Religiosität und Integration in Wechselwirkung zueinander stehen: aufgeklärte Lebensweise nach den Vorgaben des Islams unterstützt die Integration in die (deutsche) Gesellschaft und eine lebendige Integration könnte zur Stärkung der Religiosität beitragen. Darüber hinaus ist die Auseinandersetzung der Befragten mit dem Bild der Frau, der Konsumgesellschaft, der Familie, der Weltreligionen, der Werterziehung und mit der Gegenüberstellung Religion/Tradition äußerst interessant und lebendig. Wenn hier dennoch eine nicht-muslimische Autorin eine qualitative Studie über den Islam vorlegt, so hat dies noch mehr das Ziel, die interreligiösen Erfahrungen und Begegnungen zu ermuntern.The best way for the Islamic world of faith to open itself is made possible through the personal with Moslem believers. Consequently the qualitative interviews of this study give us an insight into the life of Moslem women in Freiburg, they point out their religiousness and plans of life arising from it. The investigation has demonstrated that religiousness and integration have a reciprocal influence: an enlightened way of life based upon the guidelines of Islam supports the integration in the (German) society and a successful integration could contribute to a strengthening of religiousness. In addition, the confrontation of the interviewed with the image of the woman, consumer society, family, religions of the world, ethical education and with the opposition between religion and tradition is very interesting and lively. If this present study is a qualitative study submitted by a non-Moslem woman, it is even more intended to encourage the interreligious experiences and encounters

The price is not right: Reducing mobile telecommunications bills in Canada

Over the past decade, the Canadian mobile telecommunications service market has grown at an exceptional rate, ultimately overtaking landlines as the dominant form of telecommunication. Mobile telecommunications has therefore become an essential service in the lives of most Canadians. However Canadian consumers continue to face some of the highest mobile service prices in the developed world. This study seeks to identify the principal causes of continued high mobile telecommunications prices in Canada, and to suggest potential policy solutions to lower service costs for consumers. This study involves a combination of expert interviews, secondary research, and case study analysis of the Australian, U.S. and Saskatchewan mobile markets. This study identifies high levels of market concentration as a principal cause, and recommends that mandated MVNO access be implemented to address high prices in the Canadian mobile service market

Narración digital para el desarrollo de habilidades del siglo XXI en la enseñanza del inglés en la educación secundaria

Taking into consideration the lively interest of the educational community in digital storytelling and the development of 21st century skills, this research paper presents the theoretical background, design and implementation of an action research, conducted in a Junior High School in the English language course, using digital storytelling to develop 21st century skills.The action research took place during the school years 2018-20. Participants were the 110 students of the 2nd grade. The aim of the research was to determine whether digital storytelling, as an educational tool, can support the development of 21st century skills, and more specifically critical thinking, creativity, collaboration and communication, in the English language course in secondary education. The research methodology combined qualitative and quantitative data from various sources. The quantitative data were gathered from questionnaires and rubrics. The qualitative data were collected from the digital stories, the interviews of the participants and the research diary of the teacher researcher.The results seem to confirm one of the two research questions that the action research sought to identify. While critical thinking and creativity skills were significantly developed in the participants, collaborative and communication skills were not developed to the expected degree. However, the collaborative framework and the interpersonal communication that was developed between the team members laid the foundations for the successful development of critical and creative thinking skills.Finally, further interpretation of the research can be the starting point for researching the use of digital storytelling in the wider educational context. The study lays the groundwork for new research extensions on gender, ethnicity, background, use of digital storytelling for language education, students' level of competence in English and ICT skills and finally the use of digital storytelling in the initiative 21st Century Skills Labs. As 21st century skills are an emerging field of educational research, the lack of relevant literature on the development of these skills through digital storytelling, in the Greek educational context, makes this research very significant.Λαμβάνοντας υπόψη το έντονο ενδιαφέρον της εκπαιδευτικής κοινότητας για την ψηφιακή αφήγηση και την ανάπτυξη δεξιοτήτων του 21ου αιώνα, το συγκεκριμένο ερευνητικό πόνημα παρουσιάζει το θεωρητικό υπόβαθρο, το σχεδιασμό και την υλοποίηση μιας έρευνας δράσης, που διεξήχθη σε ένα Γυμνάσιο της περιφέρειας στο μάθημα της αγγλικής γλώσσας, με τη χρήση της ψηφιακής αφήγησης για την ανάπτυξη δεξιοτήτων του 21ου αιώνα. Η έρευνα δράσης έλαβε χώρα κατά τη διάρκεια των σχολικών ετών 2018-20. Συμμετέχοντες ήταν 110 μαθητές της Β΄ Γυμνασίου. Σκοπός της έρευνας ήταν να διαπιστώσει εάν η ψηφιακή αφήγηση, ως εκπαιδευτικό εργαλείο, μπορεί να υποστηρίξει την ανάπτυξη δεξιοτήτων του 21ου αιώνα, και πιο συγκεκριμένα την κριτική σκέψη, τη δημιουργικότητα, τη συνεργατικότητα και τη διαπροσωπική επικοινωνία, στο μάθημα των Αγγλικών στη δευτεροβάθμια εκπαίδευση. Η μεθοδολογία της έρευνας συνδύασε ποσοτικά και ποιοτικά δεδομένα που προήλθαν από ποικίλες πηγές. Τα ποσοτικά δεδομένα προήλθαν από ερωτηματολόγια και κλίμακες διαβαθμισμένων κριτηρίων. Τα ποιοτικά δεδομένα προήλθαν από ψηφιακές αφηγήσεις, ομαδικές συνεντεύξεις, ημερολόγιο παρατήρησης και σημειώσεις πεδίου της ερευνήτριας εκπαιδευτικού. Τα αποτελέσματα φαίνεται να επαληθεύουν ένα από τα δύο ερευνητικά ερωτήματα που η έρευνα δράσης επιδίωξε να διαπιστώσει. Ενώ οι δεξιότητες της κριτικής σκέψης και της δημιουργικότητας αναπτύχθηκαν σημαντικά στους συμμετέχοντες, οι δεξιότητες της συνεργατικότητας και της επικοινωνίας δεν αναπτύχθηκαν στον αναμενόμενο βαθμό. Ωστόσo, το ομαδοσυνεργατικό πλαίσιο και η διαπροσωπική επικοινωνία που αναπτύχθηκε μεταξύ των μελών των ομάδων έθεσαν τις βάσεις για την επιτυχημένη ανάπτυξη των δεξιοτήτων της κριτικής και δημιουργικής σκέψης στους μαθητές. Η περαιτέρω ερμηνεία της έρευνας μπορεί να αποτελέσει την αφετηρία για έρευνα σχετικά με τη χρήση της ψηφιακής αφήγησης στο ευρύτερο εκπαιδευτικό πλαίσιο. Η μελέτη θέτει τις βάσεις για νέες ερευνητικές προεκτάσεις που αφορούν το φύλο, την εθνικότητα, την καταγωγή, το επίπεδο ικανότητας των μαθητών στην αγγλική γλώσσα και στις ΤΠΕ και τέλος τη χρήση της ψηφιακής εκπαίδευσης για τη γλωσσική εκπαίδευση και τα Εργαστήρια Δεξιοτήτων του 21ου αιώνα. Καθώς οι δεξιότητες του 21ου αιώνα είναι ένας αναδυόμενος τομέας εκπαιδευτικής έρευνας, η έλλειψη σχετικής βιβλιογραφίας που αφορά την ανάπτυξη των δεξιοτήτων αυτών μέσα από την ψηφιακή αφήγηση, στο ελληνικό εκπαιδευτικό πλαίσιο, καθιστά την παρούσα έρευνα πολύ σημαντική.Teniendo en cuenta el gran interés de la comunidad educativa por la narración digital y el desarrollo de habilidades del siglo XXI, este artículo de investigación presenta los antecedentes teóricos, el diseño y la implementación de una investigación de acción, realizada en una escuela secundaria en el curso de idioma inglés, que utilizó la narración digital para desarrollar habilidades del siglo XXI. La investigación de acción se llevó a cabo durante los años escolares 2018-20. Los participantes fueron 110 estudiantes del la segunda clase de un colegio en la secundaria. El objetivo de la investigación fue determinar si la narración digital, como herramienta educativa, puede apoyar el desarrollo de habilidades del siglo XXI, y más específicamente el pensamiento crítico, la creatividad, la colaboración y la comunicación interpersonal, en el curso de inglés en los estudiantes en la educación secundaria. La metodología de investigación combinó datos cuantitativos y cualitativos de una variedad de fuentes. Los datos cuantitativos provienen de cuestionarios y escalas de criterios calificados. Los datos cualitativos provienen de narrativas digitales, entrevistas grupales, diario de observación y notas de investigación de campo del profesor investigador. Los resultados parecen confirmar una de las dos preguntas de investigación que la investigación de acción buscaba identificar. Si bien las habilidades de pensamiento crítico y creatividad se desarrollaron significativamente en los participantes, las habilidades de colaboración y comunicación no se desarrollaron en el grado esperado. Sin embargo, el marco colaborativo y la comunicación interpersonal que se desarrolló entre los miembros del equipo sentaron las bases para el desarrollo exitoso de las habilidades de pensamiento crítico y creativo. Finalmente, una mayor interpretación de la investigación puede ser el punto de partida para la investigación sobre el uso de la narración digital en el contexto educativo más amplio. El estudio sienta las bases para nuevas extensiones de investigación sobre género, etnia, antecedentes, uso de la narración digital para la educación de idiomas, el nivel de inglés de los estudiantes y las habilidades TIC y, finalmente, el uso de la educación digital en los laboratorios de habilidades del siglo XXI. Dado que las habilidades del siglo XXI son un campo emergente de investigación educativa, la falta de literatura relevante sobre el desarrollo de estas habilidades a través de la narración digital en el contexto educativo griego hace que esta investigación sea muy importante

High-level Structured Interactive Programs with Registers and Voices 1,2

Abstract: A model (consisting of rv-systems), a core programming language (for developing rv-programs), several specification and analysis techniques appropriate for modeling, programming and reasoning about interactive computing systems have been introduced by Stefanescu in 2004 using register machines and space-time duality, see [Stefanescu 2006, Stefanescu 2006b]. Later on, Dragoi and Stefanescu have introduced structured programming techniques for programming rv-systems and have presented a kernel programming language AGAPIA v0.1 for interactive computing systems, see [Dragoi and Stefanescu 2006a, Dragoi and Stefanescu 2006b]. AGAPIA v0.1 has a restricted format for program construction, using a “3-level ” grammar for their definition: the procedure starts with simple while programs, then modules are defined, and finally AGAPIA v0.1 programs are obtained applying structured rvprogramming statements on top of modules. In the current paper the above restriction is completely removed. By an appropriate reshaping interface technique, general programs may be encapsulated into modules, allowing to reiterate the above “3-level ” construction of programs, now starting with arbitrary AGAPIA programs, not with simple while programs. This way, high-level interactive programs are obtained. The extended version is called AGAPIA v0.2. As a case study we consider a cluster of computers, each having a dynamic set of running processes. We present a protocol for the communication and termination detection in this system and implement the protocol in our AGAPIA v0.2 language. We also describe the operational semantics of the program using high-level scenarios, i.e., scenarios where, recursively, the cells may themselves contain scenarios, at a lower, refined level

High-level Structured Interactive Programs with Registers and Voices

A model (consisting of rv-systems), a core programming language (for developing rv-programs), several specification and analysis techniques appropriate for modeling, programming and reasoning about interactive computing systems have been introduced by Stefanescu in 2004 using register machines and space-time duality, see [Stefanescu 2006, Stefanescu 2006b]. Later on, Dragoi and Stefanescu have introduced structured programming techniques for programming rv-systems and have presented a kernel programming language AGAPIA v0.1 for interactive computing systems, see [Dragoi and Stefanescu 2006a, Dragoi and Stefanescu 2006b]. AGAPIA v0.1 has a restricted format for program construction, using a "3-level" grammar for their definition: the procedure starts with simple while programs, then modules are defined, and finally AGAPIA v0.1 programs are obtained applying structured rvprogramming statements on top of modules. In the current paper the above restriction is completely removed. By an appropriate reshaping interface technique, general programs may be encapsulated into modules, allowing to reiterate the above "3-level" construction of programs, now starting with arbitrary AGAPIA programs, not with simple while programs. This way, high-level interactive programs are obtained. The extended version is called AGAPIA v0.2. As a case study we consider a cluster of computers, each having a dynamic set of running processes. We present a protocol for the communication and termination detection in this system and implement the protocol in our AGAPIA v0.2 language. We also describe the operational semantics of the program using high-level scenarios, i.e., scenarios where, recursively, the cells may themselves contain scenarios, at a lower, refined level

Strategy-Based and Knowledge-Based Models of Information Flow: Equivalence and Decidability

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