30 research outputs found

    Estabilidade de cor de resinas acrĂ­licas de provisĂłrios de prĂłtese fixa

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    INTRODUÇÃO: O PMMA Ă© dos materiais mais frequentemente utilizados em PrĂłtese Fixa como material para elaboração de coroas/pontes provisĂłrias. Recentemente tĂȘm sido adicionados ao mercado resinas adaptadas Ă  tecnologia CAD/CAM como forma de superar aspetos negativos das resinas ditas convencionais Ă  base do PMMA (resina acrĂ­lica e bis-acrĂ­lica). Estas restauraçÔes frequentemente sĂŁo elaboradas em zonas estĂ©ticas, pelo que a sua alteração de cor Ă© um aspeto importante a ter em conta na seleção da resina a utilizar. O objetivo deste estudo Ă© avaliar a estabilidade de cor de diferentes resinas utilizadas na confeção de provisĂłrios em prĂłtese fixa. MATERIAL E MÉTODOS: Para este estudo experimental foram confecionados quinze provetes de cada tipo de resina (resina acrĂ­lica, resina bis-acrĂ­lica, resina de fresagem, resina de impressĂŁo 3D), de forma circular e de dimensĂ”es padronizadas (10mm de diĂąmetro e 2mm de espessura), totalizando 60 provetes em estudo. Estes foram imersos em diferentes soluçÔes (ĂĄgua destilada, vinho e cafĂ©) por um perĂ­odo de dez dias. A avaliação quantitativa da alteração de cor foi realizada de acordo com o sistema CIELAB com recurso a um colorĂ­metro calibrado PCE-CSM 5 (PCE instrumentsÂź). Os dados adquiridos foram submetidos a uma anĂĄlise estatĂ­stica do programa SPSS com um nĂ­vel de significĂąncia de 0,05. RESULTADOS: A solução cafĂ© apresenta os resultados de alteração de cor mais elevados em todos os materiais. Por outro lado, a solução de ĂĄgua destilada apresentou os valores mais baixos. Quanto aos materiais concluiu-se que as resina TAB e de Fresagem diferem significativamente de todos os outros materiais, mas as resinas Structur e de impressĂŁo 3D sĂŁo estatisticamente idĂȘnticas CONCLUSÃO: ApĂłs as imersĂ”es nas respetivas soluçÔes e as mediçÔes de cor com o colorĂ­metro, a resina que se manteve mais estĂĄvel foi a resina TAB 2000Âź, por outro lado, a mais instĂĄvel foi a resina de ImpressĂŁo 3D (Dental SandÂź). Em relação Ă s soluçÔes analisadas, o cafĂ© foi a que demonstrou maiores valores de alteração de cor, sendo a ĂĄgua destilada a que melhor resultado apresentou.INTRODUCTION: PMMA is one of the most commonly used materials in Fixed Prosthodontics for the fabrication of temporary crowns/bridges. Recently, CAD/CAMadapted resins have been introduced to the market as a way to overcome the drawbacks of conventional resins, PMMA-based resins (acrylic and bis-acrylic resins). These restorations are often fabricated in esthetic areas, making color stability an important aspect to consider when selecting the resin to be used. The aim of this study is to evaluate the color stability of different resins used in the fabrication of fixed prosthodontic temporaries. METHODOLOGY: For this experimental study, fifteen specimens of each resin type (acrylic resin, bis-acrylic resin, milling resin, 3d printing resin) were fabricated in circular shape with standardized dimensions (10mm diameter and 2mm thickness), totaling 60 specimens in the study. These specimens were immersed in different solutions (distilled water, wine, and coffee) for a period of ten days. Quantitative color change evaluation was performed using the CIELAB system with a calibrated colorimeter, PCE-CSM 5 (PCE instrumentsÂź). The acquired data were subjected to statistical analysis using the SPSS software with a significance level of 0.05. RESULTS: The coffee solution showed the highest color change results for all materials. On the other hand, the distilled water solution had the lowest values. As for the materials, it was concluded that TAB resin and milling resin differed significantly from all other materials, while Structur resin and 3D-printed resin were statistically identical. CONCLUSION: After immersion in the respective solutions and color measurements with the colorimeter, TAB 2000Âź resin demonstrated the highest color stability, whereas 3D-printed resin (Dental SandÂź) showed the least stability. Among the analyzed solutions, coffee exhibited the highest color change values, while distilled water showed the best result

    Earth Stewardship Science—Transdisciplinary Contributions to Quantifying Natural and Cultural Heritage of Southernmost Africa

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    Evaluating anthropogenic changes to natural systems demand greater quantification through innovative transdisciplinary research focused on adaptation and mitigation across a wide range of thematic sciences. Southernmost Africa is a unique field laboratory to conduct such research linked to earth stewardship, with ‘earth’ as in our Commons. One main focus of the AEON’s Earth Stewardship Science Research Institute (ESSRI) is to quantify the region’s natural and cultural heritage at various scales across land and its flanking oceans, as well as its time-scales ranging from the early Phanerozoic (some 540 million years) to the evolution of the Anthropocene (changes) following the emergence of the first human-culture on the planet some 200 thousand years ago. Here we illustrate the value of this linked research through a number of examples, including: (i) geological field mapping with the aid of drone, satellite and geophysical methods, and geochemical fingerprinting; (ii) regional ground and surface water interaction studies; (iii) monitoring soil erosion, mine tailing dam stability and farming practices linked to food security and development; (iv) ecosystem services through specific biodiversity changes based on spatial logging of marine (oysters and whales) and terrestrial (termites, frogs and monkeys) animals. We find that the history of this margin is highly episodic and complex by, for example, the successful application of ambient noise and groundwater monitoring to assess human-impacted ecosystems. This is also being explored with local Khoisan representatives and rural communities through Citizen Science. Our goal is to publicly share and disseminate the scientific and cultural data, through initiatives like the Africa Alive Corridor 10: ‘Homo Sapiens’ that embraces storytelling along the entire southern coast. It is envisioned that this approach will begin to develop the requisite integrated technological and societal practices that can contribute toward the needs of an ever-evolving and changing global ‘village’

    Euclid preparation. Optical emission-line predictions of intermediate-z galaxy populations in GAEA for the Euclid Deep and Wide Surveys

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    International audienceIn anticipation of the Euclid Wide and Deep Surveys, we present optical emission-line predictions at intermediate redshifts from 0.4 to 2.5. Our approach combines a mock light cone from the GAEA semi-analytic model to self-consistently model nebular emission from HII regions, narrow-line regions of active galactic nuclei (AGN), and evolved stellar populations. Our analysis focuses on seven optical emission lines: Hα\alpha, HÎČ\beta, [SII]λλ6717,6731\lambda\lambda 6717, 6731, [NII]λ6584\lambda 6584, [OI]λ6300\lambda 6300, [OIII]λ5007\lambda 5007, and [OII]λλ3727,3729\lambda\lambda 3727, 3729. We find that Euclid will predominantly observe massive, star-forming, and metal-rich line-emitters. Interstellar dust, modelled using a Calzetti law with mass-dependent scaling, may decrease observable percentages by a further 20-30% with respect to our underlying emission-line populations from GAEA. We predict Euclid to observe around 30-70% of Hα\alpha-, [NII]-, [SII]-, and [OIII]-emitting galaxies at redshift below 1 and under 10% at higher redshift. Observability of HÎČ\beta-, [OII]-, and [OI]- emission is limited to below 5%. For the Euclid-observable sample, we find that BPT diagrams can effectively distinguish between different galaxy types up to around redshift 1.8, attributed to the bias toward metal-rich systems. Moreover, we show that the relationships of Hα\alpha and [OIII]+HÎČ\beta to the star-formation rate, and the [OIII]-AGN luminosity relation, exhibit minimal changes with increasing redshift. Based on line ratios [NII]/Hα\alpha, [NII]/[OII], and [NII]/[SII], we further propose novel z-invariant tracers for the black hole accretion rate-to-star formation rate ratio. Lastly, we find that commonly used metallicity estimators display gradual shifts in normalisations with increasing redshift, while maintaining the overall shape of local calibrations. This is in tentative agreement with recent JWST data

    Euclid preparation. Optical emission-line predictions of intermediate-z galaxy populations in GAEA for the Euclid Deep and Wide Surveys

    No full text
    International audienceIn anticipation of the Euclid Wide and Deep Surveys, we present optical emission-line predictions at intermediate redshifts from 0.4 to 2.5. Our approach combines a mock light cone from the GAEA semi-analytic model to self-consistently model nebular emission from HII regions, narrow-line regions of active galactic nuclei (AGN), and evolved stellar populations. Our analysis focuses on seven optical emission lines: Hα\alpha, HÎČ\beta, [SII]λλ6717,6731\lambda\lambda 6717, 6731, [NII]λ6584\lambda 6584, [OI]λ6300\lambda 6300, [OIII]λ5007\lambda 5007, and [OII]λλ3727,3729\lambda\lambda 3727, 3729. We find that Euclid will predominantly observe massive, star-forming, and metal-rich line-emitters. Interstellar dust, modelled using a Calzetti law with mass-dependent scaling, may decrease observable percentages by a further 20-30% with respect to our underlying emission-line populations from GAEA. We predict Euclid to observe around 30-70% of Hα\alpha-, [NII]-, [SII]-, and [OIII]-emitting galaxies at redshift below 1 and under 10% at higher redshift. Observability of HÎČ\beta-, [OII]-, and [OI]- emission is limited to below 5%. For the Euclid-observable sample, we find that BPT diagrams can effectively distinguish between different galaxy types up to around redshift 1.8, attributed to the bias toward metal-rich systems. Moreover, we show that the relationships of Hα\alpha and [OIII]+HÎČ\beta to the star-formation rate, and the [OIII]-AGN luminosity relation, exhibit minimal changes with increasing redshift. Based on line ratios [NII]/Hα\alpha, [NII]/[OII], and [NII]/[SII], we further propose novel z-invariant tracers for the black hole accretion rate-to-star formation rate ratio. Lastly, we find that commonly used metallicity estimators display gradual shifts in normalisations with increasing redshift, while maintaining the overall shape of local calibrations. This is in tentative agreement with recent JWST data

    Euclid preparation. Optical emission-line predictions of intermediate-z galaxy populations in GAEA for the Euclid Deep and Wide Surveys

    No full text
    International audienceIn anticipation of the Euclid Wide and Deep Surveys, we present optical emission-line predictions at intermediate redshifts from 0.4 to 2.5. Our approach combines a mock light cone from the GAEA semi-analytic model to self-consistently model nebular emission from HII regions, narrow-line regions of active galactic nuclei (AGN), and evolved stellar populations. Our analysis focuses on seven optical emission lines: Hα\alpha, HÎČ\beta, [SII]λλ6717,6731\lambda\lambda 6717, 6731, [NII]λ6584\lambda 6584, [OI]λ6300\lambda 6300, [OIII]λ5007\lambda 5007, and [OII]λλ3727,3729\lambda\lambda 3727, 3729. We find that Euclid will predominantly observe massive, star-forming, and metal-rich line-emitters. Interstellar dust, modelled using a Calzetti law with mass-dependent scaling, may decrease observable percentages by a further 20-30% with respect to our underlying emission-line populations from GAEA. We predict Euclid to observe around 30-70% of Hα\alpha-, [NII]-, [SII]-, and [OIII]-emitting galaxies at redshift below 1 and under 10% at higher redshift. Observability of HÎČ\beta-, [OII]-, and [OI]- emission is limited to below 5%. For the Euclid-observable sample, we find that BPT diagrams can effectively distinguish between different galaxy types up to around redshift 1.8, attributed to the bias toward metal-rich systems. Moreover, we show that the relationships of Hα\alpha and [OIII]+HÎČ\beta to the star-formation rate, and the [OIII]-AGN luminosity relation, exhibit minimal changes with increasing redshift. Based on line ratios [NII]/Hα\alpha, [NII]/[OII], and [NII]/[SII], we further propose novel z-invariant tracers for the black hole accretion rate-to-star formation rate ratio. Lastly, we find that commonly used metallicity estimators display gradual shifts in normalisations with increasing redshift, while maintaining the overall shape of local calibrations. This is in tentative agreement with recent JWST data

    Euclid preparation. Sensitivity to neutrino parameters

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    International audienceThe Euclid mission of the European Space Agency will deliver weak gravitational lensing and galaxy clustering surveys that can be used to constrain the standard cosmological model and extensions thereof. We present forecasts from the combination of these surveys on the sensitivity to cosmological parameters including the summed neutrino mass MÎœM_\nu and the effective number of relativistic species NeffN_{\rm eff} in the standard Λ\LambdaCDM scenario and in a scenario with dynamical dark energy (w0waw_0 w_aCDM). We compare the accuracy of different algorithms predicting the nonlinear matter power spectrum for such models. We then validate several pipelines for Fisher matrix and MCMC forecasts, using different theory codes, algorithms for numerical derivatives, and assumptions concerning the non-linear cut-off scale. The Euclid primary probes alone will reach a sensitivity of σ(MÎœ)=\sigma(M_\nu)=56meV in the Λ\LambdaCDM+MÎœM_\nu model, whereas the combination with CMB data from Planck is expected to achieve σ(MÎœ)=\sigma(M_\nu)=23meV and raise the evidence for a non-zero neutrino mass to at least the 2.6σ2.6\sigma level. This can be pushed to a 4σ4\sigma detection if future CMB data from LiteBIRD and CMB Stage-IV are included. In combination with Planck, Euclid will also deliver tight constraints on ΔNeff<0.144\Delta N_{\rm eff}< 0.144 (95%CL) in the Λ\LambdaCDM+MÎœM_\nu+NeffN_{\rm eff} model, or ΔNeff<0.063\Delta N_{\rm eff}< 0.063 when future CMB data are included. When floating (w0,wa)(w_0, w_a), we find that the sensitivity to NeffN_{\rm eff} remains stable, while that to MÎœM_\nu degrades at most by a factor 2. This work illustrates the complementarity between the Euclid spectroscopic and imaging/photometric surveys and between Euclid and CMB constraints. Euclid will have a great potential for measuring the neutrino mass and excluding well-motivated scenarios with additional relativistic particles
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