| 2. |
- Stephansson, Ove, et al.
(author)
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Modelling of excavation, thermal loading and bentonite swelling pressure for a waste repository
- 1991
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In: High level radioactive waste management. - New York : American Society of Civil Engineers (ASCE). - 0872628310 ; , s. 1375-1381
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Conference paper (peer-reviewed)abstract
- For the performance assessment of a future nuclear waste repository, the excavation of the tunnel and deposition hole, thermal loading from waste heat release and the swelling pressure of buffer material are factors to be considered. In this paper, they are modelled numerically by using the three-dimensional distinct element code (3DEC). The modelling is carried out in the vicinity of the tunnel and deposition hole and focused on the stability and safety of the repotory. The results indicate that thermal loading has significant influence on the stability of the tunnel and the effect of excavation and swelling pressure on the deposition hole and waste canister is insignificant.
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| 3. |
- Wahlestedt, C, et al.
(author)
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Neuropeptide Y receptor subtypes, Y1 and Y2
- 1990
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In: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 611:1, s. 7-26
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Research review (peer-reviewed)abstract
- Heterogeneity among NPY (and PYY) receptors was first proposed on the basis of studies on sympathetic neuroeffector junctions, where NPY (and PYY) can exert three types of action: 1) a direct (e.g., vasoconstrictor) response; 2) a postjunctional potentiating effect on NE-evoked vasoconstriction; and 3) a prejunctional suppression of stimulated NE release; the two latter phenomena are probably reciprocal, since NE affect NPY mechanisms similarly. It was found that amidated C-terminal NPY (or PYY) fragments, e.g., NPY 13-36, could stimulate selectively prejunctional NPY/PYY receptors, which were termed Y2-receptors. Consequently, the postjunctional receptors which were activated poorly by NPY/PYY fragments, were termed Y1-receptors. Later work has indicated that the Y2-receptor may occur postjunctionally in selected sympathetic effector systems. The central nervous system appears to contain a mixture of Y1- and Y2-receptors as indicated by functional as well as binding studies. For instance, NPY and NPY 13-36 produced diametrically opposite effects on behavioral activity, indicating the action of the parent peptide on two distinct receptors. Cell lines, most importantly neuroblastomas, with exclusive populations of Y1- or Y2-receptors, have been characterized by binding and second messenger studies. In this work, selective agonists for the two receptor subtypes were used. Work of many investigators has formed the basis for subclassifying NPY/PYY effects being mediated by either Y1- or Y2-receptors. A preliminary subclassification based on effects of NPY, PYY, fragments and/or analogs is provided in Table 6. It is, however, to be expected that further receptor heterogeneity will be revealed in the future. It is argued that mast cells possess atypical NPY/PYY receptors. The histamine release associated with stimulation of the latter receptors may, at least in part, underlie the capacity of NPY as well as of short C-terminal fragments to reduce blood pressure. Fragments, such as NPY 22-36, appear to be relatively selective vasodepressor agents because of their weak vasopressor properties.(ABSTRACT TRUNCATED AT 400 WORDS)
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