Abstract: Methods for measuring the perfusion of fluid in a substance are shown to include subjecting the fluid to electromagnetic energy so as to cause a response related to the magnetization of the fluid before it enters the substance, performing magnetic resonance measurements on the substance to generate intensity information and processing the intensity information to determine perfusion. In one embodiment of the invention, perfusion is measured by labeling atoms in the fluid at a base point, generating a steady state in the substance by continuing to label atoms until the effect caused by labeled atoms perfusing in the substance, reaches a steady state, generating image information for the substance and processing the image information to determine perfusion. It is preferred to label atoms by applying magnetic resonance perturbation. In one embodiment the labeling of atoms involves saturating spins associated with the atoms.

Abstract: A subtractive time of flight technique for MR angiography and quantitative blood flow measurement. Proton spins of water in the arterial supply to a tissue or organ are inverted in a steady-state fashion by applying constant amplitude off-resonance radio frequency pulses in the presence of a constant linear magnetic field gradient to effect adiabatic fast passage transport-induced inversion of spins which move in the direction of the gradient. An angiogram is formed by subtracting an image acquired with the arterial inversion pulse from a control image acquired with no arterial inversion. By inverting the spins in a steady-state manner, no cardiac gating is necessary for imaging organs. However, cardiac gating is desirable when imaging the heart so that spins of blood passing through the coronary arteries can be inverted during systole, when most of the blood is in the left ventricle, and imaged at end diastole, when most of the blood is in the coronary arteries.

Abstract: A method of inhibiting the abnormal postnatal axial growth of the eye of a maturing animal during conditions ordinarily leading to said abnormal growth, which comprises (1) determining the neurochemical present in the retina of said eye, eg., dopamine, the concentrations of which is reduced during said conditions, and (2) administering to said eye during post natal maturation effective amounts of said neurochemical, its agonist or its antagonist.

Abstract: The synthesis of stable, ten-membered, cyclic conjugated enediynes is described. Said compounds were successfully employed to cleave double-stranded DNA spontaneously at ambient temperatures.

Abstract: Peptides comprising the tripeptide sequence of arginine-tyrosine-aspartic acid, linked from amino- to carboxy-terminus, are inhibitors of fibrinogen binding, platelet aggregation, glycoprotein IIb-IIIa binding and related aberrant and normal physiological conditions.

Abstract: Methods of constructing pulse sequences to selectively excite frequency bands in NMR imaging, spectroscopic and optical systems are disclosed. In preferred embodiments, selective .pi./2, .pi., and refocusing hard and soft pulses are constructed for perturbing the spins of the system. In NMR imaging, for example, the desired magnetization is written as an (N+1)th order Fourier series in .omega.t, where .omega. is the off-resonance frequency. In addition, if all pulses have the same phase, then the z magnetization is known to be symmetric in frequency, and the resulting hard pulse sequence can be written as an Nth order Fourier cosine series. Given this Fourier series representing the desired z magnetization, an inversion may be used to determine the hard pulse sequence of N pulses which will actually yield the desired response. In particular, if one starts with a specification of a desired z magnetization not as a Fourier series in .omega.

Abstract: Cross-linked polymer networks derived from polyaniline and polyaniline derivatives are provided, as well as preparative methods therefor. Also provided are gels comprising cross-linked polymer and a liquid.The cross-linked polymers preferably are prepared by providing a substantially linear polymer which comprises polyaniline and/or a polyaniline derivative, admixing the linear polymer with a liquid in which the cross-linked polymer is substantially insoluble, and cross-linking the polymer through agitation.The cross-linked polymers of the invention can be employed to fabricate shaped articles which reversibly expand and contract in either an isotropic or anisotropic fashion and may find use in gas and/or liquid separations.