Prevention of Erosion and Abrasion by a High Fluoride Concentration Gel Applied at High Frequencies

Ziel dieser Studie war es, den maximal erreichbaren Schutz des Zahnschmelzes nach Erosion und Erosion in Verbindung mit Abrasion durch hochkonzentriertes Fluoridgel mit zusätzlichem Fluorid aus Zahnpasta zu ermitteln. 36 Rinderzahnschmelzproben wurden täglich sechsmal alle zwei Stunden für 30 s einer Erosion mit 1%iger Zitronensäure (pH 2,3) unterzogen. Im Anschluss an den jeweiligen Erosions-Zyklus erfolgte eine 12 stündige Remineralisationsphase mit künstlichem Speichel. Die Proben wurden jeweils vor Beginn und am Ende des täglichen Erosions Zyklus gruppenspezifisch wie folgt behandelt: Täglich zweimal eine Applikation eines Zahnpasta Speichel Gemisches (120 s) mit einer speziell hergestellten Zahnpasta (Elmex®, ohne Fluorid, GABA GmbH, Münchenstein, Schweiz) (Gruppe T0). Täglich zweimal eine Applikation eines Zahnpasta Speichel Gemisches mit einer fluoridierten Zahnpasta (1250 ppm F, Elmex®) (Gruppe TF). Täglich zweimal eine Applikation eines Zahnpasta Speichel Gemisches mit einer fluoridierten Zahnpasta (Elmex®) und zusätzlich täglich zweimal eine Applikation eines sauren Fluoridgels (12500 ppm F, Elmex® gelée) für 120 s (Gruppe 2F). Täglich zweimal eine Applikation eines Zahnpasta Speichel Gemisches mit einer fluoridierten Zahnpasta (Elmex®) und zusätzlich täglich achtmal Applikation eines sauren Fluoridgels (12500 ppm F, Elmex® gelée) (Gruppe 8F). Während der täglichen Applikation des Zahnpasta Speichel Gemisches wurde wiederum ein Abschnitt jeder Probe zusätzlich einer Bürstabrasion von 15 s (60 Bürststriche) unterzogen. Die Bürstabrasion allein konnte profilometrisch nicht gemessen werden, da der Zahnschmelzverlust dafür zu gering war. Nach 14 Tagen zeigten die profilometrischen Messungen der Erosion ohne Abrasion, dass die Proben, die mit Elmex® gelée täglich zwei- bzw. achtmal behandelt wurden, signifikant weniger Schmelzverlust (24/19 ?m) aufzeigten, als die, die mit fluoridfreier, bzw. fluoridierter Zahnpasta (45/41 ?m) behandelt wurden. Nach 14 Tagen Erosion mit Bürstabrasion zeigte die zwei- bzw. achtmalige Applikation des Fluoridgeles (33/29 ?m) ebenfalls einen signifikant geringeren Schmelzverlust als die Behandlung mit fluoriedfreier, bzw. fluoridierter Zahnpasta (62/57 ?m). Aus den Ergebnissen der vorliegenden Studie lässt sich schließen, dass hoch konzentriertes saures Fluoridgel mit Aminfluorid (Elmex® gelée) einen signifikant größeren Schutz des Zahnschmelzes vor Erosion und Erosion in Verbindung mit Abrasion bietet, wobei die täglich zweimalige Anwendung anhand dieser Versuchsergebnisse optimal erscheint. Die Behandlung mit fluoridierter Zahnpasta hingegen bietet nur einen geringen Schutz des Zahnschmelzes

GPU fast multipole method with lambda-dynamics features

A significant and computationally most demanding part of molecular dynamics simulations is the calculation of long-range electrostatic interactions. Such interactions can be evaluated directly by the naïve pairwise summation algorithm, which is a ubiquitous showcase example for the compute power of graphics processing units (GPUS). However, the pairwise summation has O(N^2) computational complexity for N interacting particles; thus, an approximation method with a better scaling is required. Today, the prevalent method for such approximation in the field is particle mesh Ewald (PME). PME takes advantage of fast Fourier transforms (FFTS) to approximate the solution efficiently. However, as the underlying FFTS require all-to-all communication between ranks, PME runs into a communication bottleneck. Such communication overhead is negligible only for a moderate parallelization. With increased parallelization, as needed for high-performance applications, the usage of PME becomes unprofitable. Another PME drawback is its inability to perform constant pH simulations efficiently. In such simulations, the protonation states of a protein are allowed to change dynamically during the simulation. The description of this process requires a separate evaluation of the energies for each protonation state. This can not be calculated efficiently with PME as the algorithm requires a repeated FFT for each state, which leads to a linear overhead with respect to the number of states. For a fast approximation of pairwise Coulombic interactions, which does not suffer from PME drawbacks, the Fast Multipole Method (FMM) has been implemented and fully parallelized with CUDA. To assure the optimal FMM performance for diverse MD systems multiple parallelization strategies have been developed. The algorithm has been efficiently incorporated into GROMACS and subsequently tested to determine the optimal FMM parameter set for MD simulations. Finally, the FMM has been incorporated into GROMACS to allow for out-of-the-box electrostatic calculations. The performance of the single-GPU FMM implementation, tested in GROMACS 2019, achieves about a third of highly optimized CUDA PME performance when simulating systems with uniform particle distributions. However, the FMM is expected to outperform PME at high parallelization because the FMM global communication overhead is minimal compared to that of PME. Further, the FMM has been enhanced to provide the energies of an arbitrary number of titratable sites as needed in the constant-pH method. The extension is not fully optimized yet, but the first results show the strength of the FMM for constant pH simulations. For a relatively large system with half a million particles and more than a hundred titratable sites, a straightforward approach to compute alternative energies requires the repetition of a simulation for each state of the sites. The FMM calculates all energy terms only a factor 1.5 slower than a single simulation step. Further improvements of the GPU implementation are expected to yield even more speedup compared to the actual implementation.2021-11-1

PD 3.0: Educational Technology in Language Teaching at the tertiary level in Hong Kong, perceptions and implications for future adoption

This exploratory, interpretive study investigates the current state of professional development involving Information Communication Technology in tertiary educational institutions in Hong Kong. The study aims to explore tertiary teachers’ engagement as well as attitudes and beliefs regarding the usefulness of these professional development activities. In recent years, the Hong Kong government has invested considerably in the educational sector at the tertiary level on information technology communication specific skills and technology. The stated aim of this increased emphasis is to better prepare students and teachers to learn and teach in the 21st century, and to increase the effectiveness of the engagement with the course material. Thus, there is a strong demand for today’s teachers to cope with integrating information communication technology in their classrooms. The study employed data collection in two distinct phases, a questionnaire (n=58) which was analysed using descriptive statistics, followed by 12 semi-structured interviews analysed using thematic analysis. The original contribution of this study is new insight into PD needs in ICT skills, focusing on the context of the Hong Kong tertiary educational sector. The findings offer a richer and deepened understanding of tertiary teachers’ engagement with professional development involving Information Communication Technology. They generally exhibit a preference for informal, collaborative, interpersonal types of professional development over the more formal, institutionally mandated, isolated forms. Moreover, the findings illustrate that teachers are largely enthusiastic to participate in professional development activities, though there exists a misalignment between teachers' own professional development goals and those of their host institutions. Specifically, the lack of incorporation of viewpoints and direction from teachers regarding what type of professional development activities are better suited to enhance their teaching. The results suggest ways that professional development of tertiary teachers in Hong Kong might be more closely aligned with teachers' own goals and preferences while still serving the educational goals of the institutions

Dalla Children's alla Young Adult Literature. Traduzione e commento del romanzo "This Is Where It Ends" di Marieke Nijkamp.

Il seguente lavoro di tesi concerne la traduzione parziale del testo "This Is Where It Ends", ascrivibile al genere letterario "Young Adult". La prima parte dell'elaborato mette a confronto la letteratura per bambini (con attenzione ai problemi di denominazione e di delimitazione del genere) e la letteratura per "giovani adulti", facendo anche menzione della "letteratura crossover" e delle sue caratteristiche. Il focus successivamente si sposta e si concentra sulle strategie traduttive e le problematiche affrontate con riferimento a dei passi tratti dalla prova di traduzione. La seconda parte è dedicata interamente alla proposta di traduzione del testo

Surface parameters of stannic oxide in powder, ceramic, and gel form by nitrogen adsorption techniques Interim report

Surface parameters of stannic oxide in powder, ceramic, and gel form by nitrogen adsorption techniques - analysis of adsorption isotherm

Personal Health Record Systems as Boundary Objects

Personal health record systems are widely available and regarded as a key element in the push for electronic health records and the meaningful use of technology in medicine. However, the adoption and use of these systems has been much lower than anticipated. While research has investigated the reasons for this lack of adoption, we have no satisfactory answers. As such, we undertook a qualitative research study in a medical clinic setting to investigate them. We focused on identifying how the unique user groups who interacted with these personal health record systems viewed their use and impact. We specifically examined three different perspectives on these systems; physician, patient, and medical staff (e.g., nurses, receptionists). We found that personal health record systems function as boundary objects that reflect significantly different meanings to the various user groups who interact with them. Our results show that patients largely view these systems as non-essential adjuncts to their current care routine, physicians see the systems as tools, and medical staff members view them as an additional task or chore with questionable effectiveness. This new conceptualization of these systems as boundary objects has significant implications for their design and use

A preliminary study of certain electrical properties of stannic oxide ceramics

Tin oxide ceramics - fabrication techniques, and electrical and optical properties determinatio