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- HULTQVIST, B, et al.
(author)
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ON THE UPWARD ACCELERATION OF ELECTRONS AND IONS BY LOW-FREQUENCY ELECTRIC-FIELD FLUCTUATIONS OBSERVED BY VIKING
- 1991
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In: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - : American Geophysical Union (AGU). - 0148-0227. ; 96:A7, s. 11609-11615
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Journal article (peer-reviewed)abstract
- The dependence of the generation of upward electron beams in the to side ionosphere on the amplitude of the slow electric field fluctuations and the magnitude of the dc potential difference in the acceleration region is found to agree with the model involving the fluctuating electric field component presented in 1988 by Hultqvist. The ratio between the amplitude of the electric field fluctuations, E(f), determined by the dipole electric field experiment, and the dc acceleration voltage V(acc), given by the energy of the upflowing ion beam, is much higher on average for satellite spins showing an upward electron beam than for the spins without. It is also shown that low plasma density favors the generation of electron beams.
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- Lundin, Stefan, et al.
(author)
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Differences in transport rate of oxytocin and vasopressin analogues across proximal and distal isolated segments of the small intestine of the rat.
- 1991
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In: Pharmaceutical Research. - 1573-904X. ; 8, s. 1274-1280
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Journal article (peer-reviewed)abstract
- The transmural intestinal passage of some oxytocin and vasopressin analogues (oxytocin, OT; [Mpa1, D-Arg8]vasopressin, dDAVP; [Mpa1, Tyr (OMe)2, carba6]oxytocin, carbetocin; [Mpa1, D-Tyr (OEt)2, Thr4, Orn8]vasotocin, antocin II; [Mpa1, D-Tyr (OEt)2, Thr4, desPro7Orn8Gly9NH2]tocinoic acid-NH(CH2)3NH2, desPOG-antocin II-NH(CH2)3NH2) was studied using isolated proximal and distal segments in the rat. All peptides (measured as peptide-like immunoreactivity) displayed a higher transport rate across distal intestinal segments as determined by radioimmunoassay (RIA). The smallest peptide, des POG-antocin II-NH(CH2)3NH2, was transported at the fastest rate. No correlation of lipophilicity with transport rate was observed. Determination of the amount of peptide remaining in the mucosal media at the end of the incubation period by HPLC did not reveal any visible degradation products. However, the large difference in transport rate between [3H]OT and immuno-reactive OT indicates mucosal metabolism of this peptide. [3H]d-DAVP was distributed in a larger mucosal volume than the extracellular space marker [3H]inulin, indicating tissue uptake, but was too low (
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