The temperature dependences of the EPR linewidths for vanadyl acetylacetonate, VO(acac)2, have been measured in ethanol, n-propanol, isopropanol, n-butanol, t-butanol, trifluoroethanol, and trichloroethanol. A similar study has been carried out on vandayl trifluoroacetylacetonate, VO(tfac)2, in methanol and the solvated vanadyl ion, VO2+, in water. The EPR linewidths have been measured at 25°C for VO2+ in dimethyl sulfoxide, trimethyl phosphate, acetonitrile, N ,N-dimethylformamide, and methanol. The results are interpreted in terms of the theory proposed by Kivelson et al. to obtain rotational correlation times (τR) for the various systems. The results generally conform to the predictions of the modified Debye theory, in that τR and solvent visocity show the expected temperature dependence. Only VO(tfac)2 in methanol appears to be anomalous in this respect. A detailed analysis has shown that one of the parameters (γ) in Kivelson's expression for the linewidths is less sensitive to experimental error and therefore best suited for calculations of τR. The results indicate that at low temperature some mechanism in addition to spin–rotational relaxation is contributing to the “residual” linewidth.
Although uterine adnexal torsion is a rare phenomenon and an infrequent diagnosis, there have been several reported cases. Two cases that occurred in our practice in the past year are presented to illustrate the acute and chronic phases of the disease. This paper discusses the intrinsic and extrinsic concepts of etiologic factors of adnexal torsion and reviews the common presenting symptoms and the physical, laboratory and pathologic findings of this syndrome. An increased index of suspicion of intermittent adnexal torsion may lead to laparoscopic diagnosis and conservative therapy.
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