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Aging disrupts white matter integrity, and so does continuous elevated blood pressure that accompanies hypertension (HTN). Yet, our understanding of the interrelationship between these factors is still limited. The study aimed at evaluating patterns of changes in diffusion parameters (as assessed by quantitative diffusion fiber tracking – qDTI) following both aging, and hypertension, as well as the nature of their linkage. 146 participants took part in the study: the control group ( N = 61) and the patients with hypertension ( N = 85), and were divided into three age subgroups (25–47, 48–56, 57–71 years). qDTI was used to calculate the values of fractional anisotropy, mean, radial and axial diffusivity in 20 main tracts of the brain. The effects of factors (aging and hypertension) on diffusion parameters of tracts were tested with a two-way ANOVA. In the right hemisphere there was no clear effect of the HTN, nor an interaction between the factors, though some age-related effects were observed. Contrary, in the left hemisphere both aging and hypertension contributed to the white matter decline, following a functional pattern. In the projection pathways and the fornix, HTN and aging played part independent of each other, whereas in association fibers and the corpus callosum if the hypertension effect was significant, an interaction was observed. HTN patients manifested faster decline of diffusion parameters but also reached a plateau earlier, with highest between-group differences noted in the middle-aged subgroup. Healthy and hypertensive participants have different brain aging patterns. The HTN is associated with acceleration of white matter integrity decline, observed mainly in association fibers of the left hemisphere.

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An interference asymmetry in the angular distribution of the Ly-a quenching radiation emitted by He ions in the metastable 2s&/2 state is measured to high precision to obtain the lifetime of the 2p, /, state. The derived lifetime of (0.997 17+0.00075) X 10 ' s is the most accurate available for a fundamental atomic system. A detailed discussion of systematic corrections is included. The result is in good agreement with theory, thereby confirming the theory of radiative transition probabilities to 0.075%%uo, and indicating that differences between theory and experiment for the alkali metals must be due to either inadequate wave functions or experimental errors.PACS number(s): 32.70.Fw for spontaneous magnetic dipole (Ml) transitions from the 2s&/2 to the ls, /2 ground state and for magnetic quadrupole (M2) transitions via the 2p3/2 state. To lowest order in the field strength F= lEl, the various amplitudes are given in terms of reduced matrix elements by 46113

The hfs splitting of four lines from the array 6p7s → 6p2 as well as two lines from the array 6p8s → 6p2 of Pb I have been analyzed. A discharge tube containing metallic isotope 207Pb was used as a light source. Our experiment yields hyperfine splitting constants A for some levels of the configurations 6p2 and 6p7s: A(6p2 1D2) = (20.99 ± 0.43) mK, A(6p2 3P2) = (91.37 ± 0.34) mK, A(6p7s 3P1) = (294.16 ± 0.93) mK, A(6p7s 1P1) = (16.45 ± 0.95) mK and A = (202.04 ± 0.48) mK for the level 6p8s 3P1. Our results are compared with recent theory and other experiments.