Abstract: A magnetic resonance signal of a volume of interest within an object is acquired by placing the object in a magnetic field and the application of three successive steps. The first step comprises an rf selective 90.degree. pulse of frequency f.sub.x applied in the presence of an x-gradient magnetic field to select a slice. The magnetization of the slice is then inverted. In the second step an rf selective 90.degree. pulse of frequency f.sub.y is applied in the presence of a y-gradient magnetic field to excite a strip of the slice, in the third step an rf selective 180.degree. pulse of frequency f.sub.z is applied in the presence of a y-gradient magnetic field to refocus the magnetization of a region of said strip. The resulting free induction signal is derived solely from said region.

Abstract: A method of investigating a sample using nuclear magnetic resonance comprisesi) applying a magnetic field across the sample;ii) creating zero quantum coherences (ZQCs) within the sample during a preparation period of duration .tau.;iii) allowing the zero quantum coherences to evolve for a period of at least N.DELTA.+t.sub.1, where .DELTA., t.sub.1 are constant time intervals and N is an integer;iv) at the end of the step iii) applying a cohernece transfer pulse to create single quantum coherences;v) after a period .tau., collecting the free induction decay signal from the sample;vi) repeating steps ii) to v) with different values of N; and,vii) combining at least some of the free induction decay (FID) signals collected to generate the FID due to a single ZQC.

Abstract: Zero-quantum nuclear magnetic resonance imaging and spectroscopy in an inhomogeneous or low homogeneity magnetic field are disclosed. Specific pulse sequences have been developed which produce zero-quantum coherence resolved images and spectra. Unlike conventional NMR resolved images and spectra the zero-quantum coherence resolved images and spectra are unaffected by magnetic field inhomogeneity, thereby allowing the images and spectra of substances to be obtained where magnetic field inhomogeneity would previously have made it impossible.

Abstract: A method of obtaining an N.M.R. image of a specimen slice in the a-b plane is provided. The method comprises tipping the magnetization vector by an angle other than 180.degree.. The magnetization is then repeatedly reversed 180.degree. so as to produce a spin echo train. Simultaneously with the preceding steps, G.sub.a and G.sub.b sequences are applied in which the values of G.sub.a and G.sub.b remain constant over each spin echo while the absolute values or preferable their actual values thereof change from respective adjacent spin echoes, preferably incrementally in co-sinusoidal relationship. The tipping and reversing of the magnetization vector is preferably accomplished by means of rf pulses.

Abstract: A method of obtaining an NMR spectrum for at least a portion of a specimen slice is provided. The method comprises acquiring a number of projections of the specimen slice and shifting the projections by .DELTA.f for any point of interest. The shifted projections are then summed or compared to produce a resultant point spectrum. Preferably, shifted projections in each of a plurality of selected sets thereof are compared so as to produce a plurality of resultant spectra for the point which are used to produce a first iterated point spectrum. Additional stages of iteration are provided to minimize the effect of artifacts which comprises comparing aligned corresponding positions on an i iterated spectrum with a previously uncompared resultant point spectrum, so as to produce an i+1 iterated spectrum for the point, and repeating the foregoing a plurality of times, in each case using the iterated spectrum from the previous iteration as the i iterated spectrum.

Abstract: Derivatives have been formed from chitins and chitosans in which the amine residues on the polyglucosamine have been modified to form the groups:(a) --N.dbd.CHR or --NHCH.sub.2 R(b) --NHR'(c) --NHR" and(d) --NH--CH.sub.2 CO.sub.2 H or --NH--glycerylwhereR is an aromatic moiety having at least one hydroxyl or carboxyl group, or a macrocyclic ligandR' is an aldose or ketose residue, and,R" is an organometallic aldehyde residue.These derivatives are useful in chelating metals, in pharmaceutical formulations, in cosmetics, in chromatographic separations, in enzyme immobilization, as catalysts, etc. Galactomannans having selected amine-containing side chains have also been prepared by reductive amination.