Among the aminopyridines, 3,4-diaminopyridine (DAP) is a more effective K+ channel blocker than is 4-aminopyridine (4-AP), and, furthermore, DAP enhances neuromuscular transmission. Because 4-AP improves muscle contractility, we hypothesized that DAP would also increase force and, in addition, ameliorate fatigue and improve the neurotransmission failure component of fatigue. Rat diaphragm strip...

On rocky shores, wave-swept macroalgae experience dramatic and repeated wave-induced hydrodynamic forces. However, previous studies of macroalgal mechanics have shown that individual waves are not forceful enough to account for observed rates of breakage. Instead, fatigue may contribute to algal breakage, with damage accumulating over time in conditions of repeated loading. Here I examine the e...

Resistance to cyclic flexural fatigue failure is an important feature of rotary nickel-titanium (NiTi) instruments. The aim of this study was to evaluate the cyclic flexural fatigue failure resistance of RevoS Shaper Universal rotary NiTi files and to compare it to two other rotary NiTi files with similar size and taper, the Hero Shaper and the ProFile. Fifteen each of Revo-S Shaper Universal, ...

Fatigue damage from activities of daily living has been considered to be a major cause of aseptic loosening in cemented total hip arthroplasty. The cement-bone interface is one region where loosening could occur, but to date the fatigue response of the interface has not been examined. Cement-bone specimens were prepared from fresh frozen human cadaver tissue using simulated in vivo conditions. ...

Hydraulic support is the main supporting equipment of the coal mining systems, and they are usually subjected to fatigue failure under the high dynamic load. The fracture positions are generally at welded joints where there is a serious stress concentration. In order to investigate and further improve the fatigue strength of hydraulic support, the present work first located the possible positio...

This study was conducted to determine the prevalence of fatigue and identify its demographic, clinical, and psychological correlates in 150 heart failure (HF) patients (73% men, 66% Caucasian, mean age 55.0 years, mean ejection fraction 26.7%+/-11%), from a single HF center, using the Profile of Mood States-Fatigue Subscale, the Minnesota Living With Heart Failure Questionnaire, and the Beck De...

Electronic power devices used for transportation applications (automotive and avionics) experience severe temperature variations, which promote their thermal fatigue and failure. For example, for power modules mounted on the engine of an aircraft, temperature variations range from –55°C (in the worst case of storage before takeoff) to +200°C (flight). Direct bonded copper (DBC) substrates are u...

One of major reasons of failure of solder joints is known as the thermal fatigue. Also, The failure of the solder joints under the thermal fatigue loading is influenced by varying boundary conditions such as the material of solder joint, the materials of substrates(related the difference in CTE), the height of solder, the Distance of the solder joint from the Neutral Point (DNP), the temperatur...

Previous studies have reported women to have a greater resistance to fatigue than men during sustained handgrip exercise, however, observed gender differences in fatigue has been shown to be a function of contraction type. The purpose of the present study was to determine if gender differences exist in forearm muscle fatigue during intermittent handgrip contractions. Women [n = 11, 23.5 ± 1.5 (...

1. Abstract Conventional wind turbine blades have been designed using fatigue life predictions based on a fixed wind load distribution that does not fully capture uncertainty of the wind load. This could result in early fatigue failure of blades and eventually increase the maintenance cost of wind turbines. To produce reliable as well as economical wind turbine blades, this paper studies reliab...