Some Preliminary Observations on the Proton Magnetic Resonance in Biologic Samples

Abstract

ByE r i k 0 cl e b l a cl and Gun n a r Lin cl s t r 0 m If a sample containing atomic nuclei with a magnetic moment is placed in a magnetic field, the nuclei take up certain allowed directions with respect to the field. Transitions between these quantized directions can be induced if electromagnetic radiation with the appropriate quantum energy acts upon the sample. In a magnetic field of about 6,700 gauss the quantum energy for proton transitions is about 9 ·10 20 erg, corresponding to a frequency of about 26.5 megacycles.If this 'resonance frequency' is applied to the specimen, and the magnetic field is swept over a small interval less than a gauss, absorption of energy can be detected by the resonance absorption technique of PURCELL,

Application of proton nuclear magnetic resonance spectroscopy to the study ofCryptococcusand cryptococcosis

“…Proton ( 1 H) NMR spectroscopy is the most sensitive and widely used method. Other biologically relevant but less sensitive nuclei include 13 C, 15 N and 31 P. NMR spectroscopy has been applied to the study of microorganisms since 1955 (Odeblad & Lindström, 1955), primarily to characterize metabolic processes and identify compounds produced by microorganisms.…”

Pulse sequences for multi-frequency selective NMR excitation in inhomogeneous magnetic fields

“…In 1946 Felix Bloch and Edward Purcell independently developed NMR techniques for use on liquids and solids [3,4]. Shaw and Elsken 1950 used proton NMR to investigate the water content of vegetable materials [5] and Odebald and Lindstrom in 1955 obtained proton NMR signals from a number of mammalian samples [6]. Ernest and Anderson in 1966 introduced pulsed NMR in combination with Fourier Transform (FT) [7]; this technique is the foundation of most modern NMR experiments.…”

“…5 Signal decay due to T 2 relaxation 12 2. 6 NMR system response 13 Magnets arrangement for SPS 35 3.4 ID magnetic field profiles of SPS 36-37 3.5…”

“…The whole width 2D magnetic field profile of SPS 38 3. 6 ID field profile and the sensitive volume 39 3.7 2D profile of relatively homogeneous field magnets 40-41 3. 8 The probe 42 3.9 NMR probe circuit diagram 43 3.10 SPS's transmitter-receiver unit 44 3.11 The transmitter-receiver protection circuitry 45 The not best fitted edge response curves 57 4.…”

“…... 58-59 4:4 Mineral oil edge response best fit curves put together 59 viii 4.5 Point Spread Function of 64us pulse 61 4. 6 The plot of spatial resolution versus pulse length 62 4.7 Illustration of multi-frequency selective NMR excitation ........ 64 4.8 The rectangular RF pulse 65 4.9 Message transmission through variations in the carrier's amplitude 66 4.10 Convolving the rectangular function with a cosine carrier signal 67 4.11 NMR excitation by frequency shifts when n = 1 67 4.12 Total spectra of NMR excitation by frequency shifts 68 4.13 Relationship between FID and the phase of a signal 69…”