| 1. |
- Dahlqvist, Per, et al.
(author)
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Environmental enrichment alters nerve growth factor-induced gene A and glucocorticoid receptor messenger RNA expression after middle cerebral artery occlusion in rats
- 1999
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In: Neuroscience. - 1873-7544 .- 0306-4522. ; 93:2, s. 527-535
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Journal article (peer-reviewed)abstract
- Housing rats in an enriched environment after focal brain ischemia improves functional outcome without changes in infarct volume, suggesting neuroplastic changes outside the lesion. In this study, permanent occlusion of the middle cerebral artery was followed by housing in an enriched or a standard environment. Nerve growth factor-induced gene A and glucocorticoid receptor messenger RNA expression were determined by in situ hybridization two to 30 days after middle cerebral artery occlusion. Stroke induced a decrease in nerve growth factor-induced gene A messenger RNA expression in cortical areas outside the ischemic lesion and in the CA1 subregion of the hippocampus two to three days after ischemia. This decrease was more prolonged with environmental enrichment, lasting until 20 days. However, 30 days after focal cerebral ischemia, environmental enrichment increased nerve growth factor-induced gene A expression compared to standard housing. A reduction of hippocampal glucocorticoid receptor (type II) messenger RNA two to 12 days after stroke in standard housed rats was restored by environmental enrichment. These data suggest that improved functional outcome induced by environmental enrichment after middle cerebral artery occlusion is associated with dynamically altered expression of nerve growth factor-induced gene A messenger RNA in brain regions outside the ischemic lesion, and sustained levels of hippocampal glucocorticoid receptor messenger RNA expression.
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| 2. |
- Jönsson, Anders, 1959, et al.
(author)
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Topical local anaesthetics (EMLA) inhibit burn-induced plasma extravasation as measured by digital image colour analysis.
- 1998
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In: Burns : journal of the International Society for Burn Injuries. - 0305-4179. ; 24:4, s. 313-8
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Journal article (peer-reviewed)abstract
- Amide local anaesthetics have previously been shown to reduce oedema and improve dermal perfusion following experimental burns. Previous studies have used invasive techniques for burn oedema quantification which do not allow continuous monitoring in the same animal. The present study used digital image colour analysis to investigate the effect of topical local anaesthetics on burn-induced extravasation of Evans blue albumin. A standardised full-thickness burn injury (1 x 1 cm) was induced in the abdominal skin of anaesthetised rats. The burn area was subsequently covered with 0.5 g of lidocaine-prilocaine cream 5% (25 mg of each in 1 g; EMLA, ASTRA, Sweden) or placebo cream during the first hour post-burn. One hour after the burn trauma, animals received Evans blue dye intravenously. Skin colour appearances were recorded by macrophotography before the burn and 5, 60. 65, 90, 120, 150, and 180 min post-burn. Colour slides were digitised and colour changes were analysed using the normalised red-green-blue (n-rgb) colour system. Results showed a significant inhibition of Evans blue extravasation between 60 and 180 min post-burn in EMLA-treated animals versus controls. Topical local anaesthetics are potent inhibitors of burn-induced plasma albumin extravasation, probably by direct action on vascular permeability and by inhibition of various steps of the pathophysiological response after burn injury.
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| 5. |
- Lundell, Marie, et al.
(author)
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Breast cancer risk after radiotherapy in infancy : a pooled analysis of two Swedish cohorts of 17,202 infants
- 1999
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In: Radiation Research. - : Radiation Research Society. - 0033-7587 .- 1938-5404. ; 151:5, s. 626-632
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Journal article (peer-reviewed)abstract
- The incidence of breast cancer was studied in a cohort of 17,202 women irradiated for skin hemangioma in infancy at the Radiumhemmet, Stockholm, or the Sahlgrenska University Hospital, Gothenburg. A major part of the cohort had been treated with radium-226 applicators, and the mean absorbed dose to the breasts was 0.29 Gy (range <0.01-35.8 Gy). Two hundred forty-five breast cancers were diagnosed in the cohort during the period 1958-1993, and the standardized incidence ratio (SIR) was 1.20 (95% CI 1.06-1.36). Different dose-response models were tested, and a linear model gave the best fit. Neither age at exposure, breast dose rate, ovarian dose nor time since exposure had any statistically significant modifying effect, and breast dose was the only determinant of risk. The excess relative risk per gray (ERR/Gy) was 0.35 (95% CI 0.18-0.59), which is lower than in most other studies.
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| 6. |
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| 7. |
- Mattsson, B., et al.
(author)
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Raman scattering investigations of PEO and PPO sulphonic acids
- 1997
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In: Solid State Ionics. - : Elsevier. - 0167-2738 .- 1872-7689. ; 97:1-4, s. 309-314
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Journal article (peer-reviewed)abstract
- Sulphonic acid derivatives of polyethers, of interest as proton conducting materials, were investigated using Raman spectroscopy, focusing on influence of hydration on ion configuration and polymer conformation. Upon increasing hydration we observe a polarised mode building up at approximately 1040 cm-1, assigned to the symmetric stretching vibration of a completely hydrated SO3- group. The data suggest that the proton-sulphonic groups do not dissociate until the materials are considerably hydrated thus explaining the low proton conductivities found for these materials below a relative humidity of 75%.
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| 10. |
- Mattsson, Per, 1963
(author)
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Continuously Variable Split-Power Transmissions with Several Modes
- 1996
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Doctoral thesis (other academic/artistic)abstract
- A continuously variable transmission (CVT) of split-power design consists of a variator and an arrangement of planetary gears. A black box model describing such transmissions is presented. The model can be used for synthesis as well as loss-free analysis of split-power CVT concepts in general. The planetary gear arrangement may have an arbitrary number of shafts. It is described by a sufficient number of basic speed ratios. By using several modes, both a large overall speed ratio range and low variator power ratios can be obtained. This is necessary for optimal engine use and high transmission efficiency. In each mode, specific components are active in the transmission. The black box model includes two modes, but CVT concepts with an arbitrary number of modes can be described by combining matching two-mode CVTs. General conditions for performing mode shifts are presented. A general relationship between overall speed ratio and variator speed ratio has been derived, as well as a general relationship for variator power ratios of loss-free transmissions. Different variator types are categorized by their ratio coverage. Possible combinations of variator power ratio, overall ratio coverage and variator ratio coverage are mapped and presented graphically for different configurations. Suitable combinations of these quantities can be chosen. Design parameters included will then indicate how the CVT should be designed. On the basis of the black box model, two split-power CVT concepts for automotive use are proposed. Each of the transmissions, having a geared neutral, is an infinitely variable transmission (IVT). They do not need such devices as starting clutches or hydrodynamic torque converters. They are designed for use in front wheel drive cars with transversely mounted engines. The main components of the first IVT are a traction ball drive variator, a simple epicyclic gear train with three shafts and some gear stages. The transmission can be run in three modes, including a separate mode for reverse. The second IVT consists of a hydrostatic variator, two simple epicyclic gear trains with three shafts and a few gear stages. It can be run in two modes. Reverse drive is included in one of the modes. Losses in gear meshes and variators are estimated. Hereby, constant component efficiencies are used, as well as efficiencies calculated taking load and speed dependence of the losses into consideration.
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