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532 results on '"Gustafsson, J.-Å."'

1. Probing the dynamical and kinematical structures of detached shells around AGB stars

Author

Maercker, M., De Beck, E., Khouri, T., Vlemmings, W. H. T., Gustafsson, J., Olofsson, H., Tafoya, D., Kerschbaum, F., and Lindqvist, M.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

Aims. We aim to resolve the spatial and kinematic sub-structures in five detached-shell sources to provide detailed constraints for hydrodynamic models that describe the formation and evolution of the shells. Methods. We use observations of the 12 CO (1-0) emission towards five carbon-AGB stars with ALMA. The data have angular resolutions of 0.3 arcsec to 1arcsec and a velocity resolution of 0.3 km/s . This enables us to quantify spatial and kinematic structures in the shells. Results. The observed emission is separated into two distinct components: a more coherent, bright outer shell and a more filamentary, fainter inner shell. The kinematic information shows that the inner sub-shells move at a higher velocity relative to the outer sub-shells. The observed sub-structures confirm the predictions from hydrodynamical models. However, the models do not predict a double-shell structure, and the CO emission likely only traces the inner and outer edges of the shell, implying a lack of CO in the middle layers of the detached shell. Previous estimates of the masses and temperatures are consistent with originating mainly from the brighter subshell, but the total shell masses are likely lower limits. Conclusions. The observed spatial and kinematical splittings of the shells appear consistent with results from hydrodynamical models, provided the CO emission does not trace the H2 density distribution in the shell but rather traces the edges of the shells. It is therefore not possible to constrain the total shell mass based on the CO observations alone. Complementary observations of, e.g., CI as a dissociation product of CO would be necessary to understand the distribution of CO compared to H2., Comment: 18 pages (incl. 5 pages Appendix), 13 Figures

Published
2024
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2. The role of membrane ERα signaling in bone and other major estrogen responsive tissues.

Author

Gustafsson, KL, Farman, H, Henning, P, Lionikaite, V, Movérare-Skrtic, S, Wu, J, Ryberg, H, Koskela, A, Gustafsson, J-Å, Tuukkanen, J, Levin, ER, Ohlsson, C, and Lagerquist, MK

Subjects
Humerus, Liver, Uterus, Adipose Tissue, Thymus Gland, Cell Membrane, Animals, Mice, Estradiol, Estrogen Receptor alpha, Organ Size, Ovariectomy, Signal Transduction, Organ Specificity, Mutation, Female, Lipoylation, Feedback, Physiological, Feedback, Physiological
Abstract

Estrogen receptor α (ERα) signaling leads to cellular responses in several tissues and in addition to nuclear ERα-mediated effects, membrane ERα (mERα) signaling may be of importance. To elucidate the significance, in vivo, of mERα signaling in multiple estrogen-responsive tissues, we have used female mice lacking the ability to localize ERα to the membrane due to a point mutation in the palmitoylation site (C451A), so called Nuclear-Only-ER (NOER) mice. Interestingly, the role of mERα signaling for the estrogen response was highly tissue-dependent, with trabecular bone in the axial skeleton being strongly dependent (>80% reduction in estrogen response in NOER mice), cortical and trabecular bone in long bones, as well as uterus and thymus being partly dependent (40-70% reduction in estrogen response in NOER mice) and effects on liver weight and total body fat mass being essentially independent of mERα (

Published
2016

5. Subacute exposure to low concentrations of toluene affects dopamine-mediated locomotor activity in the rat

Author

von Euler, G, Ögren, S-O, Bondy, SC, McKee, M, Warner, M, Gustafsson, J-Å, Eneroth, P, and Fuxe, K

Subjects
Pharmacology and Pharmaceutical Sciences, Biomedical and Clinical Sciences, Administration, Inhalation, Aldosterone, Animals, Apomorphine, Calcium, Corticosterone, Dopamine, Injections, Subcutaneous, Male, Membrane Fluidity, Motor Activity, Prolactin, Rats, Rats, Inbred Strains, Receptors, Dopamine, Specific Pathogen-Free Organisms, Synaptosomes, Thyrotropin, Toluene, APOMORPHINE, DOPAMINE RECEPTOR, MEMBRANE FLUIDITY, CALCIUM, PROLACTIN, BASAL GANGLIA, Toxicology, Pharmacology and pharmaceutical sciences
Abstract

The effects of low concentrations of toluene (40-80 ppm, 3 days, 6 h/day) were investigated on spontaneous and on apomorphine-induced locomotor activity in the rat, and were correlated to effects on S(-)[N-propyl-3H(N)]-propylnorapomorphine ([3H]NPA) binding in rat neostriatal membranes, on membrane fluidity, membrane leakage, and calcium levels in synaptosomes from the frontoparietal cortex, the neostriatum and the subcortical limbic area, and on serum hormone levels. Toluene exposure (80 ppm, post-exposure delay 18 h) alone did not affect locomotor activity, but attenuated apomorphine-induced (0.05 mg/kg, s.c.) suppression of rearing, and potentiated apomorphine-induced (1 mg/kg, s.c.) increases in locomotion and rearing. Toluene exposure increased the KD value of [3H]NPA binding without affecting the Bmax. All these effects were absent at 40 ppm of toluene or at a post-exposure delay of 42 h. Toluene exposure (80 ppm, post-exposure delay of 18 h) did not affect the serum levels of prolactin, TSH, corticosterone, or aldosterone, or synaptosomal membrane fluidity and calcium levels, whereas membrane leakage was increased in the neostriatum. The present study indicates that the reduction of D-2 receptor affinity by short-term, low-dose toluene exposure is accompanied by a reduced D-2 autoreceptor function and an enhanced postsynaptic D-2 receptor function.

Published
1991

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