introduction: this study investigated the fatigue and fracture modes of race and protaper rotary instruments. materials & methods: fatigue resistance was evaluated by rotating the files 30 ° or 60 ° and with 2 or 5mm radius of curvature. race taper 06 size 25 and protaper f1 files (n=40) were used. the number of rotations to failure was analyzed by two-way anova and independent sample     t-tes...

the sorkh shale formation (lower triassic) crops out in parts of tabas block. this formation is composed of limestone, dolomite, sandstone, shale and gypsum. its lower contact with the permian rocks and its upper contact with the shotori formation is marked by distinct erosional unconformity. to determine the depositional environments of the sorkh shale formation, stratigraphic sections of goda...

Background: Muscle fatigue has been known to influence brain activity, but very little is known about how cortical centers respond to muscle fatigue.Objective: This study was conducted to investigate the effects of muscle contraction and fatigue induced by two different percents of maximal voluntary contraction (MVC) on Electroencephalography (EEG) signals.Material and Methods: In t...

Background: Fatigue in the workers reduces the individual's resistance and eventually leads to the lower performance, increased errors and accidents. This study assessed the fatigue, mental workload and the correlation between them, in operating room personnel of Hamadan hospitals, Iran. Materials and Methods: In a descriptive study, the mental workload and its association with fatigue in oper...

Introduction: Shocked rocks are known from various planetary bodies of the solar system including Earth, Moon, Mars, and several types of asteroids. It was first recognized on Earth that stages of progressive shock metamorphism can be defined [1,2,3,4] and this concept was later on confirmed for lunar rocks [5] and meteorites [6,7,8]. Initiated by the IUGS “Subcommission on the Classification o...