Microstructure formation and surface properties of a rhenanite-type glass-ceramic containing 6.0 wt% P2O5

The aim of this report was to characterize the microstructure formation of a rhenanite, NaCaPO4, glass-ceramic and to determine its surface properties. The composition of the material was (in wt%) 58.0 SiO2, 6.0 P2O5, 22.8 Na2O, 12.9 CaO, and 0.3 F. Nucleation and crystallization of the monolithic base glass was carried out at temperatures between 650 and 1000°C for one hour. To characterize the different microstructures of the glass-ceramics using scanning electron microscopy (SEM), a special sample with phosphoric acid was prepared. The control of microstructure formation resulted in the precipitation of isolated α-rhenanite crystals with a crystal size of 40 nm up to 1 μm and a crystal number density of 20 to more than 2000 particles per 100 μm2. The α-phase transformed into the β-phase at approximately 690 °C. The surface properties were determined by soaking the specimens in simulated body fluid for up to 10 d. In the process, the glass-ceramics exhibited a high surface activity. Morphological investigations after soaking showed ball-shaped hydroxyapatite-type crystals consisting of two half shells. The authors concluded that rhenanite crystals acted as heterogeneous nuclei for hydroxyapatite on the surface of the bioactive glass-ceramics. Therefore, this material was assumed to have the ability to bond to living bone

Editorial: Inorganic Biomaterials.

The intention of the editors A. R. Boccaccini and W. Höland has been to target this e-book to a broad readership and at the same time to present scientific contributions sufficiently detailed which discuss various specific fundamental aspects of inorganic biomaterials and their biomedical and dental applications. In this context, two large categories of biomaterials need to be mentioned, namely bioactive biomaterials for the replacement and regeneration of hard tissue and biocompatible, non-bioactive biomaterials for restorative dentistry. Both categories include products based on glasses or glass-ceramics as well as organic-inorganic composite materials. Among the bioactive products, BIOGLASS®, developed in the late 1960s by Prof. Dr. L. L. Hench, occupies a prominent position, being BIOGLASS® the first man-made material shown to form strong and functional bonding to leaving tissue. Sadly, Prof. Hench passed away in December 2015, at the time this e-book was being completed, it is therefore a great honor for the editors to dedicate this e-book to his memory. Indeed the book contains a comprehensive review written by Prof. Hench, in collaboration with Prof. J. R. Jones (UK), which provides a timely overview of the development and applications of bioactive glasses, including a discussion on the remaining challenges in the field. Further bioactive materials have been developed over the years by leading scientists such as Prof. Kokubo (Japan). These materials have also found their way into this book. The other contributions in this book, written by worldwide recognized experts in the field, present the latest advances in relevant areas such as scaffolds for bone tissue engineering, metallic ion releasing systems, cements, bioactive glass–polymer coatings, composites for bone regeneration, and effect of porosity on cellular response to bioceramics. In addition to bioactive materials, inorganic systems for restorative dentistry are also discussed in this e-book. Biomaterials for dental restorations consist of glassy or crystalline phases. Glass-ceramics represent a special group of inorganic biomaterials for dental restorations. Glass-ceramics are composed of at least one inorganic glassy phase and at least one crystalline phase. These products demonstrate a combination of properties, which include excellent aesthetics and the ability to mimic the optical properties of natural teeth, as well as high strength and toughness. They can be processed using special processing procedures, e.g. machining, moulding and sintering, to fabricate high quality products. The editors would like to extend their gratitude to the Frontiers team in Lausanne, Switzerland, for their outstanding dedication to make possible the publication of this e-book in a timely manner. It is our wish that the book will contribute to expand the field of inorganic biomaterials, both in terms of fundamental knowledge and applications, and that the book will be useful not only to established researchers but also to the increasing number of young scientists starting their careers in the field of inorganic biomaterials

Umjereni pravni transfer u Europi - novi razvitci na primjeru Republike Hrvatske

Im Zuge der Vorbereitung Kroatiens auf die Integration in die Europäische Union kommt es erneut und in großem Maßstab zum Transfer von Recht. Damit wiederholt sich die Übertragung von gemeinschaftsrechtlichen Regelungsmodellen, die seit inzwischen mehr als 15 Jahren in Mittel- und Osteuropa praktisch angewandt werden. Wanderungsbewegungen von Recht über Grenzen hinweg sind ein auch aus der Rechtsgeschichte bekanntes altes Geschehen. Neu ist die europapolitische Steuerung solcher Übernahmeprozesse von Recht. Sie lässt sich mit dem Begriff des moderierten Rechtstransfers kennzeichnen. Er umfasst die planmäßige Anlage und Steuerung der Vorbereitung des Beitritts der Kandidatenländer zur Europäischen Union. Der Rechtstransfer zwischen der Europäischen Union und den Ländern des Westlichen Balkans vollzieht sich in großen Themenpaketen. In diesen befinden sich nicht einzelne Regelungen oder Gesetze, sondern der gesamte, in Kapitel zerlegte gemeinschaftliche Besitzstand. Er wird mit Hilfe eines bereits seit 1990 erprobten und bewährten Mix von Instrumenten der Rechtsangleichung, der institutionellen Förderung, des Monitoring und des Dialogs mit dem EuGH nunmehr auch in die Rechtsordnungen Kroatiens und der anderen am Beitritt interessierten Ländern des Westlichen Balkans eingebracht. Zum moderierten Rechtstransfer gehört die konzeptionelle Verklammerung von Rechtsnormen und Rechtsanwendung. Im Ergebnis bewirkt wird hierdurch ein systemischer Transfer von Rechten und Regelungszusammenhängen. Das Vorgehen ist nicht ohne Probleme. Zu ihnen gehört die zumindest vorübergehende Einschränkung des Gestaltungsspielraums für den parlamentarischen Diskurs und die Gesetzgebungstätigkeit in den Beitrittsstaaten und das Risiko, dass durch den Rechtstransfer zahlreiche Abstimmungsprobleme mit fortbestehenden Rechtsbeständen verdeckt werden oder gar neu entstehen. Im Ergebnis werden die Vorteile überwiegen. Der moderierte Rechtstransfer bildet die Gewähr für eine rasche und fundierte Heranführung von Rechts- und Gesellschaftsordnungen an die Europäische Union.Tijekom pripreme Hrvatske za integraciju u Europsku uniju iznova i u velikoj mjeri dolazi do transfera prava. Time se ponavlja prenošenje onih modela reguliranja iz prava Unije koje se u međuvremenu, već više od 15 godina, praktično primjenjuje u Srednjoj i Istočnoj Europi. Selidbe prava preko granica su staro, i iz pravne povijesti poznato događanje. Novo je europskopolitičko upravljanje takvih procesa preuzimanja prava. Ono se može označiti pojmom umjerenog transfera prava. On obuhvaća plansko postavljanje i usmjeravanje pripreme pristupa zemalja-kandidatkinja Europskoj uniji. Transfer prava između Europske unije i zemalja Zapadnog Balkana odvija se u velikim tematskim paketima. U ovima se ne nalaze pojedinačne regulacije ili zakoni, već cjelovita, na poglavlja razložena stečevina Unije. Uz pomoć još od 1990. isprobane i provjerene mješavine instrumenata ujednačavanja prava, institucionalnog poticanja, monitoringa i dijaloga s Europskim sudom (EuGH?) sad se unosi i u pravni poredak Hrvatske i drugih, za pristup zainteresiranih zemalja Zapadnog Balkana. U umjereni transfer prava pripada koncepcijsko povezivanje pravnih normi i primjene prava. To ima za ishod sistemski transfer prava i regulacijskih konteksta. Postupak nije bez problema. U njega spada u najmanju ruku privremeno ograničavanje prostora koji za oblikovanje ostaje parlamentarnom diskursu i zakonodavnoj djelatnosti u državama pristupnicama i rizik, da transferom prava budu prikriveni ili čak nanovo nastaju. Na kraju će prevladavati prednosti. Umjereni transfer prava jamči brzo i utemeljeno uvođenje pravnih i društvenih poredaka u Europsku uniju

Umjereni pravni transfer u Europi - novi razvitci na primjeru Republike Hrvatske

Im Zuge der Vorbereitung Kroatiens auf die Integration in die Europäische Union kommt es erneut und in großem Maßstab zum Transfer von Recht. Damit wiederholt sich die Übertragung von gemeinschaftsrechtlichen Regelungsmodellen, die seit inzwischen mehr als 15 Jahren in Mittel- und Osteuropa praktisch angewandt werden. Wanderungsbewegungen von Recht über Grenzen hinweg sind ein auch aus der Rechtsgeschichte bekanntes altes Geschehen. Neu ist die europapolitische Steuerung solcher Übernahmeprozesse von Recht. Sie lässt sich mit dem Begriff des moderierten Rechtstransfers kennzeichnen. Er umfasst die planmäßige Anlage und Steuerung der Vorbereitung des Beitritts der Kandidatenländer zur Europäischen Union. Der Rechtstransfer zwischen der Europäischen Union und den Ländern des Westlichen Balkans vollzieht sich in großen Themenpaketen. In diesen befinden sich nicht einzelne Regelungen oder Gesetze, sondern der gesamte, in Kapitel zerlegte gemeinschaftliche Besitzstand. Er wird mit Hilfe eines bereits seit 1990 erprobten und bewährten Mix von Instrumenten der Rechtsangleichung, der institutionellen Förderung, des Monitoring und des Dialogs mit dem EuGH nunmehr auch in die Rechtsordnungen Kroatiens und der anderen am Beitritt interessierten Ländern des Westlichen Balkans eingebracht. Zum moderierten Rechtstransfer gehört die konzeptionelle Verklammerung von Rechtsnormen und Rechtsanwendung. Im Ergebnis bewirkt wird hierdurch ein systemischer Transfer von Rechten und Regelungszusammenhängen. Das Vorgehen ist nicht ohne Probleme. Zu ihnen gehört die zumindest vorübergehende Einschränkung des Gestaltungsspielraums für den parlamentarischen Diskurs und die Gesetzgebungstätigkeit in den Beitrittsstaaten und das Risiko, dass durch den Rechtstransfer zahlreiche Abstimmungsprobleme mit fortbestehenden Rechtsbeständen verdeckt werden oder gar neu entstehen. Im Ergebnis werden die Vorteile überwiegen. Der moderierte Rechtstransfer bildet die Gewähr für eine rasche und fundierte Heranführung von Rechts- und Gesellschaftsordnungen an die Europäische Union.Tijekom pripreme Hrvatske za integraciju u Europsku uniju iznova i u velikoj mjeri dolazi do transfera prava. Time se ponavlja prenošenje onih modela reguliranja iz prava Unije koje se u međuvremenu, već više od 15 godina, praktično primjenjuje u Srednjoj i Istočnoj Europi. Selidbe prava preko granica su staro, i iz pravne povijesti poznato događanje. Novo je europskopolitičko upravljanje takvih procesa preuzimanja prava. Ono se može označiti pojmom umjerenog transfera prava. On obuhvaća plansko postavljanje i usmjeravanje pripreme pristupa zemalja-kandidatkinja Europskoj uniji. Transfer prava između Europske unije i zemalja Zapadnog Balkana odvija se u velikim tematskim paketima. U ovima se ne nalaze pojedinačne regulacije ili zakoni, već cjelovita, na poglavlja razložena stečevina Unije. Uz pomoć još od 1990. isprobane i provjerene mješavine instrumenata ujednačavanja prava, institucionalnog poticanja, monitoringa i dijaloga s Europskim sudom (EuGH?) sad se unosi i u pravni poredak Hrvatske i drugih, za pristup zainteresiranih zemalja Zapadnog Balkana. U umjereni transfer prava pripada koncepcijsko povezivanje pravnih normi i primjene prava. To ima za ishod sistemski transfer prava i regulacijskih konteksta. Postupak nije bez problema. U njega spada u najmanju ruku privremeno ograničavanje prostora koji za oblikovanje ostaje parlamentarnom diskursu i zakonodavnoj djelatnosti u državama pristupnicama i rizik, da transferom prava budu prikriveni ili čak nanovo nastaju. Na kraju će prevladavati prednosti. Umjereni transfer prava jamči brzo i utemeljeno uvođenje pravnih i društvenih poredaka u Europsku uniju

Untersuchungen des Einflusses eines Magnetfeldes auf elektrochemische Reaktionen an rotierenden Elektroden

Ziel dieser Arbeit soll der Aufbau von rotierenden Elektroden für Magnetfelduntersuchungen und Untersuchungen zur Überlagerung der von Magnetfeld und Rotation beeinflussten Hydrodynamik sein. Dazu werden Scheibenelektroden in Kombination mit Redoxelektrolyten eingesetzt. - Des Weiteren werden Messungen an ebenen Elektroden durchgeführt, um den Einfluss der Magnetfeldstellung zum elektrischen Feld festzustellen. Außerdem folgen Untersuchungen, damit der Geometrieeinfluss der Abscheidungszelle und der Einfluss des Elektrolytvolumens dargestellt werden können. - Ein weiterer Arbeitspunkt ist die Klärung des Magnetfeldeinflusses auf die Nickelabscheidung. Die zu untersuchenden Parameter sind neben der Magnetfeldstärke und seiner Stellung zum elektrischen Feld die Stromdichte, die Zusammensetzung der Elektrolyte, der Einsatz von organischen Zusätzen, sowie die Abscheidung mit Partikeln im Größenbereich von ca. 150 nm. Die Schichten werden umfassend mittels Röntgendiffraktometrie, Elektronenmikroskopie, Querschliff und GDOES charakterisiert. - Diese Arbeit ist eine Fortführung meiner Studienarbeit, die sich mit der Konstruktion, dem Aufbau und der Erprobung einer geeigneten Rotationseinrichtung, die auch im Hochfeldmagneten einsetzbar ist, beschäftigte.Ilmenau, Techn. Univ., Diplomarbeit, 201

Crystallization, microstructure and properties of selected glasses and glass-ceramics in the SiO2-Li2O-ZnO-K2O-P2O5 system

The crystallization behavior of selected glasses in the multicomponent SiO2-Li2O-ZnO-K2O-P2O5 system was investigated using high-temperature X-ray diffraction and differential scanning calorimetry. Proceeding from a dental model glass with the molar composition 63.2 SiO2, 29.1 Li2O, 3.3 ZnO, 2.9 K2O and 1.5 P2O5, 20 glasses were melted, varying the concentrations of the single components systematically. Glass compositions mainly influenced the formations and dissolutions of metastable and stable phases in the temperature range of 480 to 1100 °C. In the majority of the glasses hthium disilicate (Li2Si2O5) precipitated as the main crystal phase during heating, while lithium metasilicate, lithium orthophosphate, cristobalite and quartz crystallized as secondary phases. After a one-step heat treatment microstructures of glass-ceramics and morphologies of Li2Si2O5 crystals were characterized by scanning electron microscopy. With few exceptions glass-ceramics showed a finegrained microstructure with interlocking, rodshaped Li2Si2O5 crystals with 0.5 to 10 µm in length. The corresponding glass-ceramics were processed by a hot-pressing technique to test samples for mechanical and optical measurements. Concentration variations of the base glasses caused bending strengths between 224 and 675 MPa. Within a comparison of translucency according to dental standard BS 5612 contrast ratios between 0.3 and 0.8 were determined

Apatite Glass-Ceramics: A Review

The authors would like to thank Cera Dynamics Limited, part of the James Kent Group and the Institute of Dentistry (Queen Mary University of London) for jointly funding TD

The roles, resources and competencies of employee lay judges: A cross-national study of Germany, France and Great Britain

This research project analysed and compared the roles, resources and competencies of lay judges in Germany, France and Great Britain, where lay judges take up their role through nationally distinctive routes: nomination essentially by the social partners in Germany, self-nomination in Great Britain and election in France. The primary research consisted of qualitative data collected through interviews, set against contextual information on national institutional arrangements, industrial relations, This research project analysed and compared the roles, resources and competencies of lay judges in Germany, France and Great Britain, where lay judges take up their role through nationally distinctive routes: nomination essentially by the social partners in Germany, self-nomination in Great Britain and election in France. The primary research consisted of qualitative data collected through interviews, set against contextual information on national institutional arrangements, industrial relations, and court procedures. The key findings are as follows: • The dominant influence on lay judge’s reported perception of their role is their experience of the prevailing industrial relations system in each country, mediated by the labour court structure. Routes to nomination not only reflect national systems but may reinforce them and have a bearing on employee lay judges’ sense of organisational allegiance. • While acknowledging distinct employer and employee perspectives, there was an aspiration to be impartial and a commitment to fairness. This was most unambiguously expressed in Germany and Great Britain. In France, deliberations were sometimes reported as resembling a negotiation between employee and employer lay judges, but one that had to culminate in a legally correct judgment. Very few employee lay judge interviewees reported that they experienced enduring dissonance between sitting on the employee side in the court and their role as a lay judge, although this was noted by several at the outset. • Our interview findings from lay and professional judges indicated that lay judges bring distinctive knowledge. Some of this knowledge is explicit and often specific. Lay knowledge is often tacit, however, and acquired through long exposure to workplace events. Such knowledge was valued by many professional judge interviewees as adding an extra dimension to decision-making and was seen by near-ly all our interviewees as the main contribution of lay judges to the judicial process. Crucially tacit knowledge is a form of understanding that needs to be elicited in the process of deliberations, rather than as evidence provided by an expert witness. As well as bringing knowledge to the court, lay judges also reported that they could enhance their representational and personal-professional skills by transferring knowledge and experience acquired in court back to the work-place. • Gender played some role in the motivation to become a lay judge in Great Britain and in how lay judges assessed their contribution in Germany. Some female interviewees in Britain reported that work-place problems they had personally experienced had contributed to their motivation to become a lay judge. In Germany, there were some differences between men and women in their views of the nature of their contribution: whereas men tended to emphasise the specialist knowledge they could bring to bear in deliberations, women highlighted a ‘social perspective’