BACKGROUND Home bleaching agents may exert some negative effects on surface hardness of restorative materials such as glass-ionomer cements (GICs). Since some studies have shown that some components such as hydroxyapatite (HA), as a bioactive glass, can improve the mechanical properties of dental materials, the effect of bleaching agents on surface hardness of GICs containing hydroxyapatite is ...

AIM To evaluate the effect of successive cycles of disinfection in different denture cleansers on the surface roughness and the Vickers hardness of two layers of acrylic resin (base-BL and enamel-EL) of two commercial cross-linked artificial teeth. MATERIALS AND METHODS The occlusal surfaces of 60 acrylic resin denture posterior teeth (Trilux-TLX and SR Orthosit PE-SRO) embedded in autopolyme...

bananas are climacteric fruits and controlling ripening is effective in reducing loss. this experiment studied the effect of packaging (plastic bag, edible wax and plastic bag, plastic bag and 2 or 4 g/kg potassium permanganate) over 5 weeks of cold storage on the quality and characteristics of cavendish cultivar bananas. the samples were removed from storage at 8, 16, 24, 32 and 40 days and fr...

roasting is the common shape of pistachio nuts processing and the purpose of this process is to increase the total acceptability of products. the aim of this study was the effects of hot air roasting temperatures (90, 120 and 150°c), times (20, 35 and 50 min) and air velocities (0.5, 1.5 and 2.5 m/s) on textural attributes (fracture force, hardness, apparent modulus of elasticity and compressio...

INTRODUCTION This study aims to investigate the relationship of water hardness and its calcium and magnesium content with endothelial function in a population-based sample of healthy children and adolescents. MATERIAL AND METHODS This case-control study was conducted in 2012 among 90 individuals living in two areas with moderate and high water hardness in Isfahan County, Iran. The flow-mediat...

pistachio nut is one of the most important export crops in iran. for prevention of rancidity and to ensure good quality, pistachio must be harvested in a short time and be prepared for drying in 24h.the ohadi variety of iranian raw dry pistachio nuts was selected for the experiments. instrumental hardness and sensory characteristics of pistachio nuts such as: flavor , texture and total acceptan...

We conducted nanoindentation to explore the hardness and elastic properties of silica stishovite, synthesized at high pressure and quenched to ambient conditions. A total of 10 crystallographic orientations were examined on selected grains with a maximum load of 4 or 20mN. We observed discontinuity in the load–displacement curve (pop-in) for the 1⁄22 5 1̄ and 1⁄26 2 1̄ grains subjected to a maxim...

AIM This study aimed to verify the influence of oral environment and denture cleansers on the surface roughness and hardness of two different denture base materials. METHODS A total of sixteen identical removable disc specimens (RDS) were processed. Eight RDS were made from heat-cured acrylic resin (AR) and the other eight were fabricated from thermoplastic injection moulded resin (TR). Surfa...

Four XMM-Newton observations of the core of M 31, spaced at 6 month intervals, show that the brightest point X-ray source, RX J0042.6+4115, has a 0.4–10 keV luminosity of ∼5× 1038 erg s−1, and exhibits significant variability in intensity and X-ray spectrum over a time scale of ∼100 s including hard flares; such behaviour is only observed in Z-sources and transient black hole binaries in our Ga...

background: in recent times, the decreasing groundwater reserves due to over-consumption of water resources and the unprecedented reduction of precipitation, during the past 1 decades, have resulted in a change in the volume and quality of water with time. the aim of this study was to determine the spatial and temporal variations of hardness and total dissolved solids in drinking water resource...