Cyclic-tension fatigue of aluminum alloy, Al-4Cu-1Mg, was determined by an analysis of diffracted SH and SV waves, passing through the surface and reflecting the bottom of the specimen, respectively. The internal friction of SV waves begins to increase from fatigue damage ratio(=N/Nf) of 0.5. This suggests increase of movable dislocation. From the analysis of SH waves, the logarithmic damping r...

The relationship between cellular levels of cyclic adenosine monophosphate (AMP) and slow inward calcium ion (Ca) current was studied in isolated perfused guinea pig hearts in which fast sodium ion (Na) channels had been inactivated by depolarization with potassium ions (K) or blockade with tetrodotoxin. Perfusion with 22 mM K depolarized cardiac tissue to approximately -40 mv and rendered hear...

with the expanding demand on application of magnesium alloys in automotive and aerospace industries, robust methods in fatigue characterization of commercially available magnesium alloys with high specific strength is anticipated. in this paper, rotating bending load controlled tests has been studied on specimens machined from an extrusion piece of az31b. due to asymmetric and anisotropic behav...

1 N-2-O-dibutyryl adenosine 3',5'-monophosphate (db cyclic AMP), adrenaline and aminophylline produce a potentiation of the tension developed (Td) and the maximum rate of rise of tension (dT/dt max) in the rat isolated diaphragm during indirect electrical stimulation. Aminophylline and db cyclic AMP also produce the same effect during direct stimulation. 2 Propranolol produced a depression of t...

With the expanding demand on application of magnesium alloys in automotive and aerospace industries, robust methods in fatigue characterization of commercially available magnesium alloys with high specific strength is anticipated. In this paper, rotating bending load controlled tests has been studied on specimens machined from an extrusion piece of AZ31B. Due to asymmetric and anisotropic behav...

BACKGROUND We tested the hypothesis that action potential duration (APD) restitution of normal ventricular muscle cells is different during double premature stimuli (S3) compared with a single premature stimulus (S2). We propose a possible ionic mechanism for such a difference. METHODS AND RESULTS Action potentials and isometric tension were recorded simultaneously from isolated canine right ...

Shape memory alloys exhibit a high damping capacity in the mktensite state. Results obtained from both DMA and cyclic tests under tension-compression load show that the martensite damping capacity in NiTi SMAs is a function of both strain amplitude and annealing temperature. Internal friction due to movements of martensite twin boundaries within both elastic (accommodation) and inelastic (reori...

The cyclically dominated voter model on a square is extended by taking into consideration the variation of Potts energy during the nearest neighbor invasions. We have investigated the effect of surface tension on the self-organizing patterns maintained by the cyclic invasions. A geometrical analysis is also developed to study the three-color patterns. These investigations clearly indicate that ...

This biomechanical study is the first to compare 3 fixation methods-bilateral fixed-angle plate, modified anterior tension wiring, and cannulated lag screws with anterior tension wiring-in multifragmentary distal patella fractures. A T-shaped 3-part fracture simulating a multifragmentary articular distal patella fracture (AO/OTA 34-C2.2) was created in 18 human cadaver knee specimens. Three gro...

This study determined to what extent active and passive wall tensions increase in in vivo intestinal arterioles of 13- to 15-week-old and 25- to 27-week-old spontaneously hypertensive rats (SHR) to maintain normal or smaller arteriolar diameters during microvascular hypertension. Acetylcholine and nitroprusside were used to determine whether vascular muscle relaxation to endothelium-derived rel...