924 results about "Strain rate" patented technology

Systems and methods for noninvasive assessment of cardiac tissue properties and cardiac parameters using ultrasound techniques are disclosed. Determinations of myocardial tissue stiffness, tension, strain, strain rate, and the like, may be used to assess myocardial contractility, myocardial ischemia and infarction, ventricular filling and atrial pressures, and diastolic functions. Non-invasive systems in which acoustic techniques, such as ultrasound, are employed to acquire data relating to intrinsic tissue displacements are disclosed. Non-invasive systems in which ultrasound techniques are used to acoustically stimulate or palpate target cardiac tissue, or induce a response at a cardiac tissue site that relates to cardiac tissue properties and / or cardiac parameters are also disclosed.

An ultrasound system and method for calculation and display of tissue deformation parameters are disclosed. A method to estimate a strain rate in any direction, not necessarily along the ultrasound beam, based on tissue velocity data from a small region of interest around a sample volume is disclosed. Quantitative tissue deformation parameters, such as tissue velocity, tissue velocity integrals, strain rate and / or strain, may be presented as functions of time and / or spatial position for applications such as stress echo. For example, strain rate or strain values for three different stress levels may be plotted together with respect to time over a cardiac cycle.

An elastic laminate capable of being rolled for storage and unwound from a roll when needed for use, includes an elastic layer of an array of continuous filament strands with meltblown deposited on the continuous filament strands, and a facing layer bonded to only one side of the elastic layer. The meltblown layer may include an elastic polyolefin-based meltblown polymer having a degree of crystallinity between about 3% and about 40%. The laminate suitably has an inter-layer peel strength of less than about 70 grams per 3 inches cross-directional width at a strain rate of 300 mm / min. Alternatively or additionally, the continuous filament strands and / or the facing layer may include an elastic polyolefin-based meltblown polymer having a degree of crystallinity between about 3% and about 40%. In certain embodiments, the elastic laminate may include an extensible facing layer bonded to an elastic or semi-elastic film layer having a basis weight of about 50 gsm or less, wherein the facing layer includes an elastic polyolefin-based polymer having a degree of crystallinity between about 3% and about 40%.

The invention is directed to essentially saturated hydrocarbon polymer composition comprising essentially saturated hydrocarbon polymers having A) a backbone chain, B) a plurality of essentially hydrocarbyl sidechains connected to A), said sidechains each having a number-average molecular weight of from 2500 Daltons to 125,000 Daltons and a MWD by SEC of 1.0-3.5; and having A) a Newtonian limiting viscosity (eta0) at 190° C. at least 50% greater than that of a linear olefinic polymer of the same chemical composition and weight average molecular weight, preferably at least twice as great as that of said linear polymer, B) a ratio of the rubbery plateau modulus at 190° C. to that of a linear polymer of the same chemical composition less than 0.5, preferably <0.3, C) a ratio of the Newtonian limiting viscosity (eta0) to the absolute value of the complex viscosity in oscillatory shear (eta*)at 100 rad / sec at 190° C. of at least 5, and D) a ratio of the extensional viscosity measured at a strain rate of 1 sec-1, 190° C., and time=3 sec (i.e., a strain of 3) to that predicted by linear viscoelasticity at the same temperature and time of 2 or greater. Ethylene-butene prepared by anionic polymerization and hydrogenation illustrate and ethylene-hexene copolymers prepared by coordination polymerization illustrate the invention. The invention polymers exhibit improved processing characteristics in that the shear thinning behavior closely approaches that of ideal polymers and exhibit improved strain thickening.

Methods and systems for measuring mechanical property of a vascular wall and a method and system for determining health of a vascular structure are provided wherein local deformation of a vessel wall resulting from physiologic pressures with altered transmural forces is measured. A non-invasive free-hand ultrasound scanning-procedure was performed to apply external force, comparable to the force generated in measuring a subject's blood pressure, to achieve higher strains by equalizing the internal arterial baseline pressure. When the applied pressure matched the internal baseline diastolic pressure, strain and strain rate increased by a factor of 10 over a cardiac cycle. Radial arterial strain was assessed in the vessel wall over the entire deformation procedure using a phase-sensitive, two-dimensional speckle-tracking algorithm. An elastic modulus reconstruction procedure was developed to estimate the non-linear elastic properties of the vascular wall.