Abstract: This disclosure relates to improvements in the cross section of a bottom end of a plastic bottle suitable for packaging liquids under internal pressures. The bottom end is primarily one which includes a generally hemispherical bottom wall having projecting therefrom in circumferentially spaced relation hollow legs terminating in supporting feet. The bottom end is stiffened against creep of the plastic material over a period of time under the influence of the internal pressure by changing the configuration of the bottom wall from that of a hemisphere to one which includes a configuration of straight line sections and curved line sections when viewed in radial cross section along the axis of the bottle.

Abstract: A prosthesis for an inadequate or diseased heart valve, the prosthesis being formed of a porous fabric comprising multifilament synthetic yarns supported on a plural-lobed frame. The frame has generally parallel legs each comprising a pair of rod portions. The fabric is inserted between the rod portions of the legs to form flexible leaflets. Each leaflet consists essentially of a textile of filaments having a substantial number of open interstitial spaces in the range of 20 to 40 microns evenly distributed throughout the fabric. The resulting composite structures are free of thrombogenic complications.

Abstract: Prostheses for inadequate or diseased heart valves and blood vessels, formed of fabrics comprising multifilament synthetic yarns. For a heart valve the fabric is supported on a three-lobed frame. During manufacture, the fabric is subjected to a plural step compressive shrinking and crimping process to impart nonisotropic elastic compliance approximating the natural mechanical properties. The resulting composite structures are free of thrombogenic complications.

Abstract: Apparatus for sensing particles in a fluid medium comprising an ultrasonic resonant cavity for containing a fluid medium. A first transducer on one side of the cavity continuously propagates thereacross ultrasonic compressional waves whose phase and amplitude are perturbed by the presence of particles in the fluid medium. A second transducer positioned on the opposite side of the cavity from the first transducer substantially parallel to and in registry therewith receives the ultrasonic waves and converts them to rf electric waves of the same frequency, the rf electric waves having their phases and amplitudes modulated in response to any perturbations in the ultrasonic waves. The rf waves are amplified and fedback to the first transducer thereby to establish an oscillatory circuit.