background and aims. the aim of the present study was to compare the effect of surface treatment with er; cr:yssg, nd:yag, and co2 lasers on repair shear bond strength of a silorane-based composite resin. materials and methods. sixty eight cylindrical samples of a silorane-based composite resin (filtek silorane) were prepared and randomly divided into 4 groups as follows: group 1: without surfa...

lapping is one of the most important polishing processes which can be used to fabricate flat and smooth surfaces. in this paper, the effect of lapping characteristics and mesh number of abrasive particles are studied on the surface roughness and flatness for the machining of hardened aisi 52100 rings. the most significant lapping characteristics are pressure, lap plate speed and time. scanning ...

statement of problem: in some clinical situations, repair of composite restorations is treatment of choice. improving the bond strength between one new and old composite usually requires increased surface roughness to promote mechanical interlocking since chemical bonding might not be adequate. similarly, the treatment of a laboratory fabricated resin composite restoration involves the same pro...

pyrazine derivatives are important class of compounds with diverse biological and cytotoxic activities and clinical applications. in this study, b3 p 86 / 6 – 31 + + g * was used to compute and map the molecular surface electrostatic potentials of a group of substituted amides of pyrazine-2-carboxylic acids to identify common features related to their subsequent cytotoxicities. several statisti...

this experiment was conducted to compare the effects of multi-strain probiotic inclusion levels on performance, intestinal morphology, gut microflora and hematological changes in salmonella typhimurium (st) infected broiler chickens. a total of 120 day old ross 308 broiler chickens were distributed into 20 floor pens and reared for 10 days under 5 experimental treatments including a corn-soy ba...

since heavy metals are considered as one of the major pollutants threatening, the main goal of this study was to bring out the concentrations of pb, zn and mn in the surface sediments off bushehr in the persian gulf. for this purpose, after collection of samples, the concentrations of the three metals in surface sediments were measured through the atomic absorption. the results were compared wi...

resonances are intrinsic characteristics of an elastic object, which are completely independent of thesource of excitation. the appropriate utilization of the information contained within the resonancespectra and the identification of the resonance frequencies of the object can be used as a potent toolfor material characterization. in this paper, a new mathematical model for the wave diffractio...

this paper provides an overview of how the surface properties of ferromagnetic nanoparticles dispersed in fluids is modified by natural and biocompatible polymers. among common magnetic nanoparticles, magnetite (fe3o4) and maghemite (g-fe203) are popular candidates because of their biocompatibility. natural polymeric coating materials are the most commonly used biocompatible magnetic nanopartic...

background: surface electromyography (semg) of muscles is a non-invasive tool that can be helpful in the assessment of muscle function and some motor control evaluations. a loss of force, known as muscle fatigue is accompanied by changes in muscle electrical activity. one of the most commonly used surface emg parameters which reflects paraspinal muscle fatigue during different tasks and positio...