Gunning G.M.,Trinity College Dublin |
Murphy B.P.,Trinity College Dublin |
Murphy B.P.,AMBER Inc
Acta Biomaterialia | Year: 2015
Mitral valve prolapse is often caused by either elongated or ruptured chordae tendineae (CT). In many cases, rupture is spontaneous, meaning there is no underlying cause. We hypothesised that spontaneous rupture may be due to mechanical fatigue. To investigate this hypothesis, we tested porcine marginal CT: in uniaxial tension, and in fatigue at a range of peak stresses (n = 12 at 15, 10 and 7.5 MPa respectively, n = 6 at 5 MPa). The rupture surfaces of failed CT were observed histologically, under polarised light microscopy, and SEM. The cycles to failure for 15, 10, 7.5 and 5 MPa peak stresses were: (average ± SD): 5077 ± 4366, 49513 ± 56414, 99927 ± 108908, 197099 ± 69103. A Weibull plot was constructed and from this, the number of cycles at 50% probability of failure was established in order to approximate the fatigue life, which was found to be 2.43 MPa at 10 million cycles. The rate of creep increases exponentially with increasing peak stress. Under histological examination it was observed that CT which have been fatigued at low stress partially lose their organised collagen structure and can sustain micro-cracks that can be linked to increases in the creep rate. Furthermore our SEM images closely matched descriptions from the literature of spontaneous in vivo rupture. In conclusion, we believe that the mechanical test results we present strongly suggest that spontaneous chordal rupture and chordal elongation in vivo can be caused by mechanical fatigue. © 2015 Acta Materialia Inc.
AMBER Inc | Date: 2014-08-06
A system and method for electrostatic discharge (ESD) testing devices under test (DUTs) uses an ESD gun attached to a robotic arm to execute ESD testing processes. The system and method also uses a relay station to place a DUT after an ESD testing process is performed on one major side of the DUT so the ESD testing can be performed on the other major side of the DUT.
AMBER Inc | Date: 2016-04-12
Eye glasses; Eyeglasses; Eyewear; Eyewear, namely, eye glasses, sun glasses, and reading glasses; Glasses for sports; Goggles for sports; Protective eyewear; Protective glasses; Reading glasses; Safety eyewear; Safety goggles; Sports eyewear; Sports glasses; Sun glasses; Sunglasses.
AMBER Inc | Date: 2015-02-18
Bolt snaps of metal; Buckles of common metal; Metal hardware, namely, pulleys; Metal hardware, namely, carabiners of metal; Metal hardware, namely, karabiners of metal; Metal hooks; Metal karabiners; Metal pulleys, springs and valves; Metal shackles and hooks for lifting and rigging; Pegs of metal; Pitons of metal; Metal clasps for tying down straps; Tie-down anchors; Buckles for strap, namely, buckles of common metal used with straps; Metal strapping or tie downs; Metal hardware, namely, springs.
AMBER Inc | Date: 2011-09-01
A magnetic braking, governing, or speed retarding system for use with a wheeled conveyance may take advantage of eddy currents induced when a magnet moves past a non-magnetic conductor. A plurality of magnets may be disposed within a rotor that rotates as a wheel axle rotates. The magnets rotate past one or more relatively stationary stators to generate eddy currents that create a resistance on the rotor, thereby acting to retard or slow the rotational speed of the rotor and the axle. The system may be particularly well-suited with a wheeled conveyance such as a sled that is gravity driven and travels downhill along a track. The speed governing system may apply lesser force in relatively flat sections of the track, due to slower wheel rotational speeds, and greater force as the conveyance attempts to pick up speed, e.g., in steeper sections.