Infrared images of the transiting disk in the epsilon Aurigae system.

Epsilon Aurigae (epsilon Aur) is a visually bright, eclipsing binary star system with a period of 27.1 years. The cause of each 18-month-long eclipse has been a subject of controversy for nearly 190 years because the companion has hitherto been undetectable. The orbital elements imply that the opaque object has roughly the same mass as the visible component, which for much of the last century was thought to be an F-type supergiant star with a mass of approximately 15M[symbol:see text] (M[symbol:see text], mass of the Sun). The high mass-to-luminosity ratio of the hidden object was originally explained by supposing it to be a hyperextended infrared star or, later, a black hole with an accretion disk, although the preferred interpretation was as a disk of opaque material at a temperature of approximately 500 K, tilted to the line of sight and with a central opening. Recent work implies that the system consists of a low-mass (2.2M[symbol:see text]-3.3M[symbol:see text]) visible F-type star, with a disk at 550 K that enshrouds a single B5V-type star. Here we report interferometric images that show the eclipsing body moving in front of the F star. The body is an opaque disk and appears tilted as predicted. Adopting a mass of 5.9M[symbol:see text] for the B star, we derive a mass of approximately (3.6 +/- 0.7)M[symbol:see text] for the F star. The disk mass is dynamically negligible; we estimate it to contain approximately 0.07M[symbol:see text] (M[symbol:see text], mass of the Earth) if it consists purely of dust.

Properties of Experimental Dental Composites Containing Antibacterial Silver-Releasing Filler. Materials 2018, 11, 1031.

In the published article, "Properties of Experimental Dental Composites Containing Antibacterial Silver-Releasing Filler" [...].

Properties of Experimental Dental Composites Containing Antibacterial Silver-Releasing Filler.

Secondary caries is one of the important issues related to using dental composite restorations. Effective prevention of cariogenic bacteria survival may reduce this problem. The aim of this study was to evaluate the antibacterial activity and physical properties of composite materials with silver sodium hydrogen zirconium phosphate (SSHZP). The antibacterial filler was introduced at concentrations of 1%, 4%, 7%, 10%, 13%, and 16% (w/w) into model composite material consisting of methacrylate monomers and silanized glass and silica fillers. The in vitro reduction in the number of viable cariogenic bacteria Streptococcus mutans ATCC 33535 colonies, Vickers microhardness, compressive strength, diametral tensile strength, flexural strength, flexural modulus, sorption, solubility, degree of conversion, and color stability were investigated. An increase in antimicrobial filler concentration resulted in a statistically significant reduction in bacteria. There were no statistically significant differences caused by the introduction of the filler in compressive strength, diametral tensile strength, flexural modulus, and solubility. Statistically significant changes in degree of conversion, flexural strength, hardness (decrease), solubility (increase), and in color were registered. A favorable combination of antibacterial properties and other properties was achieved at SSHZP concentrations from 4% to 13%. These composites exhibited properties similar to the control material and enhanced in vitro antimicrobial efficiency.