Dense Silicon nitride was investigated to determine the effect of its microstructural parameters and densification on thermo-mechanical properties and thermal stress resistance to fracture initiation during a hot or cold mechanical and thermal shock testing. The different materials and microstructures were obtained by changing the parameters such as the type of the powder, additive, forming p...

Microstructure-sensitive fatigue crack growth in 304 metastable austenitic stainless steel containing nanotwin bundles was studied using a miniature compact tension specimen combined with post-fatigue metallographic examinations. The single-variant nanotwinned specimens exhibited high resistance compared to the coarse-grained without bundles, regardless of lamellar orientation. In martensite va...

The low-back pain has demonstrated to be a common finding among athletes and particularly the overload in the lumbar column resulting from a strength or isometric resistance involvement of muscles of this segment as result of the muscular fatigue has been considered as important etiological factor for its development. In this context, tests used for the training evaluation of the lumbar spinae ...

The purpose of this study was to evaluate the effect of an eight-week progressive resistance training programme on lower extremity strength, ambulatory function, fatigue and self-reported disability in multiple sclerosis (MS) patients (mean disability score 3.7 +/- 0.8). Eight MS subjects volunteered for twice weekly training sessions. During the first two weeks, subjects completed one set of 8...

The purpose of this study was to investigate the effects of short term resistance exercise on neuromuscular fatigue threshold (PWCFT), strength, functional performance, and body composition in older adults. Twenty-three participants (71.2 ± 6.0 yr) were randomly assigned to 6 weeks of resistance exercise (EXE) or control (CONT). A submaximal cycle ergometer test, physical working capacity at fa...

OBJECTIVE To assess the reliability of contractile properties of the knee extensor muscles in 23 individuals with post-polio syndrome (PPS) and 18 age-matched healthy individuals. METHODS Contractile properties of the knee extensors were assessed from repeated electrically evoked contractions on 2 separate days, with the use of a fixed dynamometer. Reliability was determined for fatigue resis...

We have shown that fatigue resistance can be induced in rabbit tibialis anterior (TA) muscles without excessive power loss by continuous stimulation at low frequencies, such as 5 Hz, and that the same result is obtained by delivering a 10-Hz pattern in equal on/off periods. Here we ask whether the same phenotype could be produced with daily amounts of stimulation that would be more appropriate ...

Photochromic compounds are promising materials for optoelectronic and photonic applications because of their ability to undergo change in color under UV/Vis illumination due to reversible chemical transition from open to closed ring isomers (photocyclization). The by-produc formation may lead to irreversible photodegradation of the material, called fatigue. We use Density Functional Theory meth...

OBJECTIVES The aim of this study was to evaluate the cyclic fatigue resistance of the ProTaper Universal D1 file (Dentsply Maillefer) under continuous and adaptive motion. MATERIALS AND METHODS Forty ProTaper Universal D1 files were included in this study. The cyclic fatigue tests were performed using a dynamic cyclic fatigue testing device, which had an artificial stainless steel canal with ...