| 1. |
- Engstrom, C, et al.
(författare)
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Effects of orthodontic force on enamel formation in normal and hypocalcemic rats.
- 1986
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Ingår i: Journal of oral pathology. - 0300-9777. ; 15:2, s. 78-82
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Tidskriftsartikel (refereegranskat)abstract
- Maxillary incisors of young rats fed a diet deficient in calcium and vitamin D for 4 weeks developed hypoplastic enamel surfaces. In the enamel of maxillary incisors of deficiently fed rats as well as in normal rats, an orthodontic force (50 gm) acting on their incisors for 3-7 days induced foldings in the enamel, globular projections from the surface and marked hypoplastic defects. However, the orthodontic force produced clusters of free-lying enamel matrix only in the nutritionally deficient rats. In view of these observations, it might be concluded that disturbances in enamel formation which cause hypoplasias can be caused both by mechanical trauma and hypocalcemia. Furthermore, it seems that hypocalcemia increases the susceptibility to mechanical trauma of ameloblasts in their secretory stage. Whether the changes in enamel formation noted in the hypocalcemic rats is a direct effect of lowered serum calcium or due to the increase in parathyroid hormone is not known at present.
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| 2. |
- Reistad, N., et al.
(författare)
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Oscillator strength measurements of the resonance transitions in sodium- and magnesium-like argon
- 1986
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 34:2, s. 158-163
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Tidskriftsartikel (refereegranskat)abstract
- We have used the beam-foil technique to measure the decay of the 3p2P1/2,2P3/2 and 3d2D3/2,2D5/2 levels in Ar VIII and the 3s3p ‘P, 3s3d ' D, 3p1 lS, and 'D levels in Ar VII. Applying the ANDC method of analysis, accurate lifetimes for the 3p2P1/2,2P3/2 and 3s3p1P levels have been determined. The corresponding oscillator strengths are found to be in very good agreement with theoretical values. A comparison between theoretical and experimental f-values for the resonance transitions in the Na I isoelectronic sequence is also presented.
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