Difference in the color stability of direct and indirect resin composites

Indirect resin composites are generally regarded to have better color stability than direct resin composites since they possess higher conversion degree. OBJECTIVE: The present study aimed at comparing the changes in color (&#916;E) and color coordinates (&#916;L, &#916;a and &#916;b) of one direct (Estelite Sigma: 16 shades) and 2 indirect resin composites (BelleGlass NG: 16 shades; Sinfony: 26 shades) after thermocycling. MATERIAL AND METHODS: Resins were packed into a mold and light cured; post-curing was performed on indirect resins. Changes in color and color coordinates of 1-mm-thick specimens were determined after 5,000 cycles of thermocycling on a spectrophotometer. RESULTS: &#916;E values were in the range of 0.3 to 1.2 units for direct resins, and 0.3 to 1.5 units for indirect resins, which were clinically acceptable (&#916;E0.05), while &#916;L, &#916;a and &#916;b values were signifcantly different by the type of resins (p<0.05). For indirect resins, &#916;E values were infuenced by the brand, shade group and shade designation based on three-way ANOVA (p<0.05). CONCLUSION: Direct and indirect resin composites showed similar color stability after 5,000 cycles of thermocycling; however, their changes in the color coordinates were different

Purinergic signalling and immune cells

This review article provides a historical perspective on the role of purinergic signalling in the regulation of various subsets of immune cells from early discoveries to current understanding. It is now recognised that adenosine 5'-triphosphate (ATP) and other nucleotides are released from cells following stress or injury. They can act on virtually all subsets of immune cells through a spectrum of P2X ligand-gated ion channels and G protein-coupled P2Y receptors. Furthermore, ATP is rapidly degraded into adenosine by ectonucleotidases such as CD39 and CD73, and adenosine exerts additional regulatory effects through its own receptors. The resulting effect ranges from stimulation to tolerance depending on the amount and time courses of nucleotides released, and the balance between ATP and adenosine. This review identifies the various receptors involved in the different subsets of immune cells and their effects on the function of these cells

Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre

We provide an updated assessment of the power of the Cherenkov Telescope Array (CTA) to search for thermally produced dark matter at the TeV scale, via the associated gamma-ray signal from pair-annihilating dark matter particles in the region around the Galactic centre. We find that CTA will open a new window of discovery potential, significantly extending the range of robustly testable models given a standard cuspy profile of the dark matter density distribution. Importantly, even for a cored profile, the projected sensitivity of CTA will be sufficient to probe various well-motivated models of thermally produced dark matter at the TeV scale. This is due to CTA's unprecedented sensitivity, angular and energy resolutions, and the planned observational strategy. The survey of the inner Galaxy will cover a much larger region than corresponding previous observational campaigns with imaging atmospheric Cherenkov telescopes. CTA will map with unprecedented precision the large-scale diffuse emission in high-energy gamma rays, constituting a background for dark matter searches for which we adopt state-of-the-art models based on current data. Throughout our analysis, we use up-to-date event reconstruction Monte Carlo tools developed by the CTA consortium, and pay special attention to quantifying the level of instrumental systematic uncertainties, as well as background template systematic errors, required to probe thermally produced dark matter at these energies

Fast preparation of nano-hydroxyapatite/superhydrophilic reduced graphene oxide composites for bioactive applications

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A method for the direct electrodeposition of globular nano-hydroxyapatite (nHAp) onto reduced graphene oxide (RGO) is presented and a model for the specific growth preference is discussed. Results show that the carboxyl (carboxylic acid)/carboxylate functional groups attached directly to the RGO after oxygen plasma treatment were essential to accelerate the OH- formation and the deposition of globular nHAp crystals. High resolution scanning electron microscopy, energy dispersive X-ray and X-ray diffraction showed that homogeneous, highly crystalline, stoichiometric nHAp crystals, with preferential growth in the (002) plane direction, were formed without any thermal treatment. The nHAp/RGO composites were shown to be an appropriate surface for mesenchymal stem cell adhesion with active formation of membrane projections.13849474955Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2011/17877-7, 2011/20345-7