The question of how cooperation evolves and is maintained among nonkin is central to the biological, social, and behavioral sciences. Previous research has focused on explaining how cooperation in social dilemmas can be maintained by direct and indirect reciprocity among the participants of the social dilemma. However, in complex human societies, both modern and ancient, cooperation is frequently maintained by means of specialized third-party enforcement.
View Article and Find Full Text PDFThe present study systematically reviewed the literature regarding the bond strength durability of zirconia ceramics to resin-based luting cements after application of different bonding protocols and aging conditions. Electronic searches in PubMed, Scopus, and Web of Science databases were performed for relevant literature published between January 1st 2015 and November 15th 2022. Ninety-three (93) English language in-vitro studies were included.
View Article and Find Full Text PDFInt J Mol Sci
January 2023
Nanofillers in resin materials can improve their mechanical and physicochemical properties. The present work investigated the effects of zirconia nanoparticles (NPs) as fillers in commercial dental luting cements. Two dual-cured self-adhesive composites and one resin modified glass ionomer (RMGI) luting cement were employed.
View Article and Find Full Text PDFBackground: Yttria-stabilized zirconia nanoparticles can be applied as fillers to improve the mechanical and antibacterial properties of luting cement. The aim of this study was to synthesize yttria-stabilized zirconia nanoparticles by the sol-gel method and to investigate their composition, structure, morphology and biological properties.
Methods: Nanopowders of ZrO 7 wt% YO (nY-ZrO) were synthesized by the sol-gel method and were sintered at three different temperatures: 800, 1000 and 1200 °C, and their composition, size and morphology were investigated.
In this paper, a novel method to modify color images for the protanopia and deuteranopia color vision deficiencies is proposed. The method admits certain criteria, such as preserving image naturalness and color contrast enhancement. Four modules are employed in the process.
View Article and Find Full Text PDFNew zirconia compositions with optimized esthetic properties have emerged due to the fast-growing technology in zirconia manufacturing. However, the large variety of commercial products and synthesis routes, make impossible to include all of them under the general term of "monolithic zirconia ceramics". Ultra- or high translucent monolithic formulations contain 3-8 mol% yttria, which results in materials with completely different structure, optical and mechanical properties.
View Article and Find Full Text PDFThe purpose of this paper was to update the knowledge concerning the wear, translucency, as well as clinical performance of monolithic zirconia ceramics, aiming at highlighting their advantages and weaknesses through data presented in recent literature. New ultra-translucent and multicolor monolithic zirconia ceramics present considerably improved aesthetics and translucency, which, according to the literature reviewed, is similar to those of the more translucent lithium disilicate ceramics. A profound advantage is their high strength at thin geometries preserving their mechanical integrity.
View Article and Find Full Text PDFStatement Of Problem: Adhesive cementation is the most common bonding strategy for zirconia restorations. Although cementation with a bioactive luting agent has been proposed as an alternative, how the bond strength compares is unclear.
Purpose: The purpose of this in vitro study was to evaluate shear bond strength after cementing a monolithic zirconia ceramic to human dentin with a bioceramic cement, compare it with a traditional cement, and evaluate its bioactive properties.
Objective: This study evaluated the shear bond strength (SBS) of pretreated monolithic zirconia surfaces bonded to human dentin following immediate dentin sealing (IDS) using two different self-adhesive resin luting agents.
Methods And Materials: Sixty intact human third molars were collected, stored, sectioned appropriately, and molded according to ISO 29022:2013, resulting in 120 dentin specimens. Ceramic cylindrical specimens were fabricated using CAD/CAM technology and sintered as recommended (final bonding area A=2.
Assortative mechanisms can overcome tragedies of the commons that otherwise result in dilemma situations. Assortativity criteria include various forms of kin selection, greenbeard genes, and reciprocal behaviors, usually presuming an exogenously fixed matching mechanism. Here, we endogenize the matching process with the aim of investigating how assortativity itself, jointly with cooperation, is driven by evolution.
View Article and Find Full Text PDFIn this paper we propose a learning mechanism to systematically design fast fuzzy clustering-based vector quantizers. Although the utilization of fuzzy clustering in vector quantization is able to reduce the dependence on initialization, it finally obtains high computational cost. This problem has been investigated by many researchers.
View Article and Find Full Text PDFAfter introducing a new form of density-functional theory for the ab initio description of electronic systems in contact with a molecular liquid environment, we present the first detailed study of the impact of a solvent on the surface chemistry of Cr(2)O(3), the passivating layer of stainless steel alloys. In comparison to a vacuum, we predict that the presence of water has little impact on the adsorption of chloride ions to the oxygen-terminated surface but has a dramatic effect on the binding of hydrogen to that surface. These results indicate that the dielectric screening properties of water are important to the passivating effects of the oxygen-terminated surface.
View Article and Find Full Text PDFWe present evidence that the structure of carbonmonoxy myoglobin crystals can be altered by lowering the pH. This structural change is monitored by the characteristic Fe-CO Raman modes at 508 and 491 cm-1 and is thought to involve a localized distal pocket transition from a "closed" conformation at pH 7 to a more "open" conformation at pH 4. These changes take place in the crystal without loss of intensity of a conformationally sensitive Raman mode at 252 cm-1 that signals a partial unfolding of the globin structure in solution.
View Article and Find Full Text PDFIn epithelial cells, a barrier or tight junction restricts the diffusion of lipid probes from the apical to the basolateral side of the outer membrane bilayer. This phenomenon is studied theoretically with the diffusion equation on planar and spherical surfaces. Two models for the tight junction are considered: a penetrable barrier embedded in a monolayer and an impenetrable obstacle in the outer membrane of a bilayer than must be bypassed by flip-flopping between inner and outer membranes.
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