Nikolay V. Anisimov

Water enrichment by H2O ortho-isomer: Four-photon and NMR spectroscopy

Ratio of H2O ortho-/para-spin-isomers in water of different treatment procedures (distilled or cavitation fountain) were studied by both Rayleigh wing four-photon spectroscopy and 1H nuclear magnetic resonance (NMR) spectroscopy. Low-frequency gas-like rotational resonances were observed in the 0.1–1.5 cm−1 (3–45 GHz) spectral range and NMR proton density was measured in both water samples. We established that the intensity of ortho-isomer line (616−523)0.74 cm−1 measured by four-photon spectroscopy increases by factor of ∼3.5 after cavitation treatment of distilled water. Moreover, the proton density measured by NMR spectroscopy in the same sample grows on ∼17%. We have suggested that the enrichment of the distilled water by ortho-H2O molecules was achieved due to cavitation bubbles collapse when the water passes through the supercritical state.

The registration of signals from the nuclei other than protons at 0.5 T MRI scanner

The practical aspects of the adaptation of the medical MRI scanner for multinuclear applications are considered. Examples of high resolution NMR spectra for nuclei 19F, 31P, 23Na, 11B, 13C, 2H, and also NQR spectrum for 35Cl are given. Possibilities of MRI for nuclei 19F, 31P, 23Na, 11B are shown. Experiments on registration of signals 19F from the fluorocarbons injected in laboratory animals are described.

Calculation of optimal parameters for 19F MRI

This paper presents a method for optimizing the parameters of the scanning pulse sequences for MRI in relation to objects with a wide NMR spectrum. In this case, a broadband excitation of the spin system is difficult because of hardware limitations. It is proposed to apply the selective excitation, the optimum parameters of which are calculated by an algorithm that uses information concerning the NMR spectrum. The method is especially useful for 19F MRI of fluorocarbons.