摘要:
Arrangements are provided for assembling multiple substrates for coating within a fluidized bed coater so as to deposit a coating of uniform thickness across the entire exterior surface thereof. One embodiment includes a method for coating orthopedic implants having convex and concave surfaces with pyrocarbon by pyrolytic decomposition of a hydrocarbon.
摘要:
A prosthetic heart valve is shown which incorporates a valve body design and leaflet pivot arrangements that minimize turbulence and shear stresses having a tendency to generate thrombosis. A valve body having an axially curved entrance that is smoothly joined to a generally cylindrical body of extended axial length provides excellent fluid flow characteristics when combined with leaflets that can assume orientations perfectly aligned with the downstream flow of blood. By constructing such a pyrocarbon valve body which receives a metal ring at an appropriate location, suture rings that permit the tissue annulus to directly contact the exterior surface of the cylindrical valve body are accommodated.
摘要:
Pyrocarbon components have been found to create richer, clearer sound when employed as bridges (19), saddles (1), nuts (2), frets (3), tuning heads (4), pegs (9) and other components which contact the strings in guitars (6, 16), violins (11) and like stringed musical instruments. Bridges/saddles and nuts of stringed instruments produce a marked difference in the sound when pyrocarbon components are used compared with currently used materials. There is a significant increase in sound volume for a given intensity of string movement, along with richer harmonics and a clearer, less muddy sound. The crystalline structure of pyrolytic carbon minimizes the damping of string vibration as it is transferred to the sound-amplifying portion of acoustic instruments, producing a rich, pleasing and higher volume sound. The useful life of strings is increased in contact with pyrolytic carbon components before they go “dead” or break.
摘要:
A guitar-family-characteristic-sound selector switch (63) is incorporated into an electric guitar and used in conjunction with the normal guitar pickup selector switch (62) and the volume and tone controls. This guitar-family-characteristic-sound selector switch invokes different pickup (61) combinations and resistance/capacitance/inductance circuitry (68) in order to generate sounds characteristic of at least two other guitars in addition to the normal sound of the host guitar. In one implementation, the family selector switch is a single user controllable switch that makes the system is intuitive in that a single guitar-family-characteristic-sound selector switch is all that needs to be operated to put the guitar in the mode of sounding like one of three or more styles of guitars following such selection; the pickup selector, volume and tone controls are used in the usual manner.
摘要:
A trileaflet heart valve includes a generally annular valve body having an interior wall of nominally circular cross-section into which three wedge-shaped projections radially extend to provide three pairs of flanking flat surfaces between which three leaflets are pivotally supported. The valve body has an outwardly flaring upstream entrance end that, together with the configuration of the leaflets, assures streamlined flow and low transvalvular pressure drop. Wing sections extend laterally in both directions at angles between about 30.degree. and 50.degree. from flat central sections of the leaflets to create V-shaped cross-section leaflet bodies having short flat edge sections along the lateral edges of both wing sections that create a wide open central flow passageway. The three leaflets assume an orientation parallel or nearly parallel to the central axis in full open position. Leaflet movement from open to closed position is partially defined by upstream retainers aligned with the flat central sections of each leaflet and by surfaces formed in or on the side walls of the projections along which the leaflets slide.
摘要:
A bileaflet heart valve is shown which incorporates a pivot arrangement that minimizes resistance to downstream blood flow in the open position yet has prompt response and therefore minimal regurgitation upon flow reversal. The valve employs a pair of identical flat leaflets that can assume a precisely parallel orientation in the fully open position at or near peak downstream blood flow or can alternatively assume other low energy positions. As the downstream flow of blood slows near the end of a pumping stroke, downstream displacement of the leaflets results in their prerotation toward the closed position orientation, all being controlled by the interengagement of flat ears, which extend laterally from opposite surfaces of the leaflets, and receiving cavities of unique design. The cavities include upstream and downstream lobes separated by an intermediate throat portion defined by inward and outward fulcrums. As soon as reverse flow begins, upstream displacement of the leaflets causes the ears to contact straight camming surfaces located upstream of the outward fulcrums which, in combination with the fulcrums and a downwardly directed, concave surface at the upstream end of the upstream lobe, positively guide each leaflet through efficient closing which ends in substantially rotational movement.
摘要:
Mechanical heart valve prostheses having either a single occluder or a pair of occluders are designed to permit such occluders to assume an open position parallel to the longitudinal axis of the valve passageway. The pivot arrangements are such that an occluder pivots about a constant center or pivot axis substantially offset from the locations where engagement occurs between the occluder and the valve body, whereby prompt smooth pivoting movement toward the closed position is initiated from an open position parallel to the valve centerline. For example, elongated arcuate shoes protruding from lateral edges of the occluders follow arcuate paths of matching complementary curvature defined by grooves in diametrically opposed flat sidewall sections of the valve body.
摘要:
Bi-leaflet heart valves have valve body contours and pivot arrangements that create quick valve response to flow reversal. Valve members or leaflets, which can have flat or curved inflow and outflow surfaces, are slidably and pivotally mounted in a heart valve body of contoured profile so they can be aligned precisely parallel to blood flow in the open position. The leaflets engage either projections extending radially inward from flat wall sections in the valve body sidewall or grooves in these flat wall sections. The shape and relationship of these interengaging surfaces, together with a centrally directed surge of backflowing blood which results from the strategic location of a pair of downstream recesses in the annular valve body, cooperate to provide prompt closing rotation of the leaflets from a parallel open orientation.
摘要:
A trileaflet heart valve includes a generally annular valve body having an interior wall of nominally circular cross-section into which three wedge-shaped projections radially extend to provide three pairs of flanking flat surfaces between which three leaflets are pivotally supported. The valve body has an outwardly flaring upstream entrance end that, together with the configuration of the leaflets, assures streamlined flow and low transvalvular pressure drop. Wing sections extend laterally in both directions at angles between about 30.degree. and 50.degree. from flat central sections of the leaflets to create V-shaped cross-section leaflet bodies having short flat edge sections along the lateral edges of both wing sections that create a wide open central flow passageway. The three leaflets assume an orientation parallel or nearly parallel to the central axis in full open position. Leaflet movement from open to closed position is partially defined by upstream retainers aligned with the flat central sections of each leaflet and by surfaces formed in or on the side walls of the projections along which the leaflets slide. Radially interior edges of the leaflets are tapered to effectively eliminate cavitation.
摘要:
Bi-leaflet and single occluder heart valves have improved pivot arrangements that create quick valve response to flow reversal and minimize impact. Valve members or occluders, which have curved inflow and outflow surfaces, are slidably and pivotally mounted in a heart valve body and can be aligned precisely parallel to blood flow in the open position. Lugs on the valve members engage surfaces on projections extending radially inward from flat wall sections in the valve body sidewall, and the shape and relationship of these interengaging surfaces provide prompt initial rotation, low wear and reduced impact upon closing. Laterally directed ears engage the valve body arcuate sidewall and assist in defining the path of closing movement.