| 1. |
- Amann, F., et al.
(författare)
-
A search for murarregamma at the level of 10-13
- 1991
-
Ingår i: Proceedings of the 25th International Conference on High Energy Physics. - 9810024347 ; , s. 1070-1071
-
Konferensbidrag (refereegranskat)abstract
- The MEGA experiment, which is a search for the decay murarregamma with a branching ratio sensitivity of about 10-13, employs highly modular, fast detectors, state-of-the-art electronics, and a staged trigger with on-line filters. The detectors are contained in a 1.5-T solenoidal field produced by a superconducting magnet. Positrons are confined to the central region and are measured by a set of thin MWPCs. Photons are measured by one of four layers of pair spectrometers in the outer region. Most aspects of the design have been validated in engineering runs; data taking will begin in 1990 with much of the electron arm and one pair spectrometer layer installed.
|
|
| 2. |
- Borge, M. J. G., et al.
(författare)
-
Beta-Decay to the Proton Halo State in F-17
- 1993
-
Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 317:1-2, s. 25-30
-
Tidskriftsartikel (refereegranskat)abstract
- In the first experiment at the newly constructed ISOLDE Facility the first-forbidden beta-decay of Ne-17 into the first excited state of F-17 has been measured. It is a factor two faster than the corresponding mirror decay and thus gives one of the largest recorded asymmetries for beta decays feeding bound final states. Shell-model calculations can only reproduce the asymmetry if the halo structure of the F-17 state is taken into account.
|
|
| 3. |
- Keller, H., et al.
(författare)
-
Search for Forbidden Beta-Decays of the Drip-Line Nucleus Be-12
- 1994
-
Ingår i: Zeitschrift fur Physik A Hadrons and Nuclei. - 1431-5831 .- 0939-7922. ; 348:1, s. 61-62
-
Tidskriftsartikel (refereegranskat)abstract
- Beta-coincident gamma-rays have been measured from implanted pure samples of Be-12 separated at the LISE3 spectrometer at GANIL. An intensity of 0.040(26)% can be estimated for the branching ratio of the isospin forbidden pure-Fermi transition to the 0+ excited state of B-12 and of 0.008(6) % of the transition to the 1- excited state. Both are taken to represent upper limits. The halflife has been re-measured to be 26.1(2.4) ms.
|
|
| 4. |
- Bengtsson, G. J, et al.
(författare)
-
Determination of Radiative Lifetimes In Neutral Nitrogen Using Short Laser-pulses From A Distributed Feedback Dye-laser
- 1991
-
Ingår i: Zeitschrift für Physik D Atoms, Molecules and Clusters. - 0178-7683. ; 22:1, s. 397-399
-
Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes were determined for two short-lived states in neutral nitrogen. Following photodissociation and two-photon excitation employing the same UV source, excitation to higher states was performed with a distributed feedback dye laser (DFDL). The lifetimes were found to be tau(2p2 4d4D7/2) = 17(3) ns and tau(2p2 5s4P5/2) = 22(3) ns.
|
|
| 5. |
- Borge, M. J. G., et al.
(författare)
-
Super-Allowed Beta-Decay of Nuclei at the Drip-Line
- 1991
-
Ingår i: Zeitschrift fur Physik A Hadrons and Nuclei. - 1431-5831 .- 0939-7922. ; 340:3, s. 255-261
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated the continuous particle spectra following the beta decay of the neutron-rich nuclei that terminate the mass 6, 8, 9 and 11 isobaric chains. Strong beta transitions feeding the very top of the spectrum are found systematically. The favoured states are within a few MeV of the energy of the initial state. This phenomenon seems to be linked to the occurrence of a di-neutron structure or neutron halo in the drip-line nuclei.
|
|
| 6. |
- Cheng, Y.F., et al.
(författare)
-
TEM study of the early stages of the precipitation process in strip-cast Al3003 alloys
- 1992
-
Ingår i: Journal of Materials Research. - 0884-2914. ; 7, s. 3235-3241
-
Tidskriftsartikel (refereegranskat)abstract
- The precipitation behavior, especially the early nucleation stages, of the industrial strip-cast Al3003 alloys was investigated by using transmission electron microscopy (TEM). An icosahedral quasicrystalline phase was found as secondary particles in these strip-cast alloys after heat treatment for a few seconds. Three different nucleation paths are proposed based on the TEM observations. They have the same origin, viz. (Mn, Fe)-containing Mackay icosahedra, and are governed by the composition of alloys, especially the Mn and Si content.
|
|
| 7. |
- Fahlke, Claudia, 1964, et al.
(författare)
-
Effects of ventral striatal 6-OHDA lesions or amphetamine sensitization on ethanol consumption in the rat.
- 1994
-
Ingår i: Pharmacology, biochemistry, and behavior. - 0091-3057. ; 47:2, s. 345-9
-
Tidskriftsartikel (refereegranskat)abstract
- Female rats with continuous access to water and 6% ethanol were given bilateral ventral striatal 6-OHDA infusions, which induced pronounced striatal depletions of dopamine. The postoperative ethanol consumption of these rats was not significantly affected in comparison to vehicle-infused controls. In a second experiment, female rats received escalating doses of d-amphetamine over a 5-week period (from 1 to 9 mg/kg/injection). Control females were given saline injections. Following a 3-month drug-free interval, the females were given access to ethanol, the concentration of which was gradually increased from 2% to 12% with weekly intervals. Amphetamine-sensitized rats consumed significantly more alcohol than the saline-treated controls. Taken together, these results suggest that striatal dopaminergic mechanisms, while not necessary for basal ethanol drinking, can facilitate alcohol drinking.
|
|
| 8. |
- Fahlke, Claudia, 1964, et al.
(författare)
-
Metyrapone-induced suppression of corticosterone synthesis reduces ethanol consumption in high-preferring rats.
- 1994
-
Ingår i: Pharmacology, biochemistry, and behavior. - 0091-3057. ; 48:4, s. 977-81
-
Tidskriftsartikel (refereegranskat)abstract
- The fluid intake of male Wistar rats with simultaneous access to water and 6% ethanol was determined between 0900 and 1500 h. In high-preferring males (normally covering > 60% of their daily fluid consumption in the form of ethanol), two injections with the corticosterone synthesis inhibitor metyrapone (50 mg/kg) at 0900 h and 1200 h for 4 consecutive days significantly reduced ethanol preference such that they preferred water over alcohol. Treatment with corticosterone (0.6 mg/kg) 2 h before each metyrapone injection partially cancelled this effect of the synthesis inhibitor. By contrast, there was no significant effect of metyrapone treatment on the drinking of ethanol in low-preferring rats (normally covering < 30% of their daily fluid consumption in the form of ethanol). These results suggest that the adrenal secretion of corticosterone directly or indirectly modulates the intake of alcohol in high-preferring rats.
|
|
| 9. |
- Hultin, M, et al.
(författare)
-
Metabolism of emulsions containing medium- and long-chain triglycerides or interesterified triglycerides.
- 1994
-
Ingår i: Journal of Lipid Research. - 0022-2275 .- 1539-7262. ; 35:10, s. 1850-60
-
Tidskriftsartikel (refereegranskat)abstract
- This study compares the clearing and metabolism of three different lipid emulsions. They had the same phospholipid emulsifier and similar particle sizes. In one (LLL) the core component was long-chain triglycerides (TG), the second (MMM/LLL) contained equal molar amounts of medium- and long-chain TG, the third (MLM) contained synthetic TG with medium-chain (M) fatty acids in the 1,3-positions and a long-chain (L) fatty acid in the 2-position. In model experiments with bovine lipoprotein lipase, the MMM component was hydrolyzed preferentially in the MMM/LLL emulsion so that the initial products were M fatty acids and M monoglycerides. The MLM emulsion, in contrast, gave M fatty acids and formation of L-MG (monoglyceride) throughout hydrolysis. For in vivo studies [3H]oleic acid was incorporated into the emulsion TG as marker for the long-chain component. After bolus injection to rats, the MMM/LLL and MLM emulsions were cleared more rapidly than the LLL emulsion. This was true at all TG loads studied (4-64 mg for a 200 g rat). The labeled oleic acid was oxidized somewhat more rapidly when administered in the MLM emulsion compared to the MMM/LLL emulsion. There were only slight differences in tissue distribution of label. Hence, differences in in vivo metabolism of the long-chain fatty acids were small compared to the marked differences in TG structure and in patterns of product release during in vitro lipolysis.
|
|
| 10. |
- Lauritzen, M., et al.
(författare)
-
Cortical spreading depression is associated with arachidonic acid accumulation and preservation of energy charge
- 1990
-
Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 10:1, s. 115-122
-
Tidskriftsartikel (refereegranskat)abstract
- The present study aimed to study the relation between the release of arachidonic acid (AA) and the energy state in cerebral cortices of rats during single episodes of cortical spreading depression (CSD). The changes in concentrations of AA, labile phosphate compounds [ATP, ADP, AMP, and phosphocreatine (PCr)], and glycolytic metabolites (lactate, pyruvate, glucose, and glycogen) were studied during and following the large change of the local direct current (DC) potential. Free AA increased markedly during the DC shift, continued to increase during the subsequent 3 min, and returned to control levels at 4-5 min after CSD. PCr decreased by 38% in the first minutes following the DC shift, while ADP increased by 38%. Both returned to normal within a few minutes. ATP, AMP, and energy charge remained constant throughout the experimental period. Glucose decreased by 47% and glycogen by 34% for a few minutes following CSD, while lactate increased by 105% at 2-3 min and by 77% at 4-5 min after CSD. The metabolites returned to control levels at 10 min after CSD. Considering the constant energy charge at all time points during CSD, it is suggested that the AA rise reflects augmented phospholipase activity due to either increased intracellular [Ca2+] or receptor stimulation or both. The possibility that N-methyl-D-aspartate receptors play a role in the release of AA, and that free AA in turn could be part of the mechanism of CSD, is discussed.
|
|
