Evaluation of Direct and Indirect Methods of Repairing Fractured

INTRODUCTION: The most common technology used in producing a fixed partial denture is firing porcelain to metal. The fracture of veneering material rarely occurs, although it is one of the most striking problems in daily practise. PURPOSE: The purpose of this study was to evaluate the shear bond strength of composite to porcelain and metal by using two intraoral repair methods: direct and indirect. MATERIAL AND METHODS: The direct method was performed by using Ceramic Repair System (Ivoclar, Lichtenstein) with and without sandblasting. The indirect method involved Co-Jet system (ESPE,Germany) and Rely X ARC (3M,USA) as luting agents. 180 specimens fabricated with feldspathic porcelain and Ni-Cr alloy were divided into 3 groups: CR/0 (direct method of repair without sandblasting), CR/S (direct method of repair with sandblasting) and CJ (indirect method based on Co-Jet system). Each of them was divided into 3 subgroups of 20: porcelain (P), porcelain and metal (P/M) and metal (M). The 10 specimens were then subjected to a shear test in a mechanical testing machine at a crosshead speed of 0.5 mm/min. Mode of failure was recorded. Means and standart deviations of loads were calculated. RESULTS: Tested groups exhibited the following values in megapascals: CR/0-P = 20.36 ± 3.05; CR/0-P/M = 19.45 ± 3.49; CR/0-M = 10.86 ± 4.1; CR/S-P = 18.21 ± 2.62; CR/S-P/M = 19.34 ± 1.76; CR/S-M = 9,54 ± 2.48; CJ-P = 19.85 ± 1.94; CJ-P/M = 19,78 ± 3.60; CJ-M = 13.56 ± 3.82. The mean fractured loads were significantly lower for metal subgroups than for porcelain and porcelain/ metal subgroups. CONCLUSION: Higher shear bond strength is expected when porcelain was fractured without extensive metal exposure

Evaluation of Direct and Indirect Methods of Repairing Fractured

INTRODUCTION: The most common technology used in producing a fixed partial denture is firing porcelain to metal. The fracture of veneering material rarely occurs, although it is one of the most striking problems in daily practise. PURPOSE: The purpose of this study was to evaluate the shear bond strength of composite to porcelain and metal by using two intraoral repair methods: direct and indirect. MATERIAL AND METHODS: The direct method was performed by using Ceramic Repair System (Ivoclar, Lichtenstein) with and without sandblasting. The indirect method involved Co-Jet system (ESPE,Germany) and Rely X ARC (3M,USA) as luting agents. 180 specimens fabricated with feldspathic porcelain and Ni-Cr alloy were divided into 3 groups: CR/0 (direct method of repair without sandblasting), CR/S (direct method of repair with sandblasting) and CJ (indirect method based on Co-Jet system). Each of them was divided into 3 subgroups of 20: porcelain (P), porcelain and metal (P/M) and metal (M). The 10 specimens were then subjected to a shear test in a mechanical testing machine at a crosshead speed of 0.5 mm/min. Mode of failure was recorded. Means and standart deviations of loads were calculated. RESULTS: Tested groups exhibited the following values in megapascals: CR/0-P = 20.36 ± 3.05; CR/0-P/M = 19.45 ± 3.49; CR/0-M = 10.86 ± 4.1; CR/S-P = 18.21 ± 2.62; CR/S-P/M = 19.34 ± 1.76; CR/S-M = 9,54 ± 2.48; CJ-P = 19.85 ± 1.94; CJ-P/M = 19,78 ± 3.60; CJ-M = 13.56 ± 3.82. The mean fractured loads were significantly lower for metal subgroups than for porcelain and porcelain/ metal subgroups. CONCLUSION: Higher shear bond strength is expected when porcelain was fractured without extensive metal exposure

Another note on Kempisty's generalized continuity

Under a fairly mild completeness condition on spaces Y and Z we show that every x-continuous function f:X×Y×Z→M has a substantial set C(f) of points of continuity. Some odds and ends concerning a related earlier result shown by the authors are presented. Further, a generalization of S. Kempisty's ideas of generalized continuity on products of finitely many spaces is offered. As a corollary from the above results, a partial answer to M. Talagrand's problem is provided

Agent-based interoperability for e-government

The provision of valuable e-government services depends upon the capacity to integrate the disperse provision of services by the public administration and thus upon the availability of interoperability platforms. These platforms are commonly built according to the principles of service oriented architectures, which raise the question of how to dynamically orchestrate services while preserving information security. Recently, it was presented an e-government interoperability model that preserves privacy during the dynamic orchestration of services. In this paper we present a prototype that implements that model using software agents. The model and the prototype are briefly described; an illustrative use case is presented; and the advantages of using software agents to implement the model are discussed. © Springer International Publishing Switzerland 2013

FVM 1.0: a nonhydrostatic finite-volume dynamical core for the IFS

We present a nonhydrostatic finite-volume global atmospheric model formulation for numerical weather prediction with the Integrated Forecasting System (IFS) at ECMWF and compare it to the established operational spectral-transform formulation. The novel Finite-Volume Module of the IFS (henceforth IFS-FVM) integrates the fully compressible equations using semi-implicit time stepping and non-oscillatory forward-in-time (NFT) Eulerian advection, whereas the spectral-transform IFS solves the hydrostatic primitive equations (optionally the fully compressible equations) using a semi-implicit semi-Lagrangian scheme. The IFS-FVM complements the spectral-transform counterpart by means of the finite-volume discretization with a local low-volume communication footprint, fully conservative and monotone advective transport, all-scale deep-atmosphere fully compressible equations in a generalized height-based vertical coordinate, and flexible horizontal meshes. Nevertheless, both the finite-volume and spectral-transform formulations can share the same quasi-uniform horizontal grid with co-located arrangement of variables, geospherical longitude–latitude coordinates, and physics parameterizations, thereby facilitating their comparison, coexistence, and combination in the IFS. We highlight the advanced semi-implicit NFT finite-volume integration of the fully compressible equations of IFS-FVM considering comprehensive moist-precipitating dynamics with coupling to the IFS cloud parameterization by means of a generic interface. These developments – including a new horizontal–vertical split NFT MPDATA advective transport scheme, variable time stepping, effective preconditioning of the elliptic Helmholtz solver in the semi-implicit scheme, and a computationally efficient implementation of the median-dual finite-volume approach – provide a basis for the efficacy of IFS-FVM and its application in global numerical weather prediction. Here, numerical experiments focus on relevant dry and moist-precipitating baroclinic instability at various resolutions. We show that the presented semi-implicit NFT finite-volume integration scheme on co-located meshes of IFS-FVM can provide highly competitive solution quality and computational performance to the proven semi-implicit semi-Lagrangian integration scheme of the spectral-transform IFS.</p

Last glacial atmospheric CO2 decline due to widespread Pacific deep-water expansion

Ocean circulation critically affects the global climate and atmospheric carbon dioxide through redistribution of heat and carbon in the Earth system. Despite intensive research, the nature of past ocean circulation changes remains elusive. Here we present deep-water carbonate ion concentration reconstructions for widely distributed locations in the Atlantic Ocean, where low carbonate ion concentrations indicate carbon-rich waters. These data show a low-carbonate-ion water mass that extended northward up to about 20° S in the South Atlantic at 3–4 km depth during the Last Glacial Maximum. In combination with radiocarbon ages, neodymium isotopes and carbon isotopes, we conclude that this low-carbonate-ion signal reflects a widespread expansion of carbon-rich Pacific deep waters into the South Atlantic, revealing a glacial deep Atlantic circulation scheme different than commonly considered. Comparison of high-resolution carbonate ion records from different water depths in the South Atlantic indicates that this Pacific deep-water expansion developed from approximately 38,000 to 28,000 years ago. We infer that its associated carbon sequestration may have contributed critically to the contemporaneous decline in atmospheric carbon dioxide, thereby helping to initiate the glacial maximum

The Cyprinodon variegatus genome reveals gene expression changes underlying differences in skull morphology among closely related species

Genes in durophage intersection set at 15 dpf. This is a comma separated table of the genes in the 15 dpf durophage intersection set. Given are edgeR results for each pairwise comparison. Columns indicating whether a gene is included in the intersection set at a threshold of 1.5 or 2 fold are provided. (CSV 13 kb

GRB 080319B: A Naked-Eye Stellar Blast from the Distant Universe

Long duration gamma-ray bursts (GRBs) release copious amounts of energy across the entire electromagnetic spectrum, and so provide a window into the process of black hole formation from the collapse of a massive star. Over the last forty years, our understanding of the GRB phenomenon has progressed dramatically; nevertheless, fortuitous circumstances occasionally arise that provide access to a regime not yet probed. GRB 080319B presented such an opportunity, with extraordinarily bright prompt optical emission that peaked at a visual magnitude of 5.3, making it briefly visible with the naked eye. It was captured in exquisite detail by wide-field telescopes, imaging the burst location from before the time of the explosion. The combination of these unique optical data with simultaneous gamma-ray observations provides powerful diagnostics of the detailed physics of this explosion within seconds of its formation. Here we show that the prompt optical and gamma-ray emissions from this event likely arise from different spectral components within the same physical region located at a large distance from the source, implying an extremely relativistic outflow. The chromatic behaviour of the broadband afterglow is consistent with viewing the GRB down the very narrow inner core of a two-component jet that is expanding into a wind-like environment consistent with the massive star origin of long GRBs. These circumstances can explain the extreme properties of this GRB.Comment: 43 pages, 18 figures, 3 tables, submitted to Nature May 11, 200