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- Berntsson, Thore, 1947, et al.
(author)
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Towards Sustainabel Oil Refinery - Pre-study for larger co-operation project
- 2008
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Reports (other academic/artistic)abstract
- In this report, the Chalmers EnergiCentrum (CEC) presents the results of a pre-study commissioned by Preem relating to the effective production of future vehicle fuels.This pre-study was made up of three studies focusing on energy streamlining, the utilisation of waste heat and carbon-dioxide separation and biorefinement relating to the gasification and hydration of vegetable oils. One of the common starting points for these studies was the current situation at the Preem refineries in Göteborg and Lysekil from where the measurement data were obtained and analysed. The report summarises the knowledge situation based on current research in the individual technical fields. The results present some interesting future opportunities for developing the sustainable production of future vehicle fuels. The sections vary, as the areas that have been examined differ and the sections have been written by different people. The reports ends with some joint conclusions and a number of questions which could be included and answered in a more extensive future main study, as part of a developed research partnership between Preem and the Chalmers University of Technology. The preliminary results of this work were analysed with the client at workshops on 1 October and 29 November 2007. The report is written in English combined with an extensive summary in Swedish including a proposal on a future main study. The study was conducted by the Chalmers EnergiCentrum (CEC), in collaboration with a number of researchers in the CEC’s network. They included Thore Berntsson, Jessica Algehed, Erik Hektor and Lennart Persson Elmeroth, all from Heat and Power Technology, Börje Gevert, Chemical and Biological Engineering, Tobias Richards, Forest Products and Chemical Engineering, Filip Johnsson and Anders Lyngfelt, Energy Technology, and Per-Åke Franck and Anders Åsblad, CIT Industriell Energianalys AB. The client, Preem, was represented by Bengt Ahlén, Sören Eriksson, Johan Jervehed, Bertil Karlsson, Gunnar Olsson, Ulf Kuylenstierna, Stefan Nyström, Martin Sjöberg and Thomas Ögren. Tobias Richards was responsible for compiling the report and Bertil Pettersson was the project manager.
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| 3. |
- Horiuchi, Yoshihito, et al.
(author)
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Role of histamine release in nonspecific vasodilatation during anodal and cathodal iontophoresis
- 2004
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In: Microvascular research. - : Elsevier BV. - 0026-2862. ; 67:2, s. 192-196
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Journal article (peer-reviewed)abstract
- Nonspecific vasodilatation during iontophoresis is an important confounding factor in experimental pharmacology. In this investigation, we studied the involvement of sensory nerves and histamine-related reactions in causing nonspecific vasodilatation in a model of anodal and cathodal iontophoresis of sodium chloride. Firstly, we applied a mixture of local anesthetic (EMLA) cream to confirm its suppressive effect on nonspecific vasodilatation and to measure its efficacy in three different dosages (duration: 1, 2, and 3 h). We then investigated the role of histamine in nonspecific vasodilatation by giving an oral antihistamine drug (cetirizine) to subjects who had and had not been given EMLA. We found substantial suppression of the nonspecific vasodilatation in all EMLA-treated groups (all dosages) compared with untreated controls (with suppression rates of 60–65%). Dosage had no significant effect. A further suppression of nonspecific vasodilatation was seen after oral cetirizine during anodal and cathodal iontophoresis in both EMLA-treated and untreated groups. The antihistamine effect was most pronounced during anodal iontophoresis. These results suggest a histaminergic increase in perfusion that may be independent of neurogenic mechanisms and depend on polarity (anode or cathode). Local nerve blocks (EMLA) together with cetirizine may therefore be used to reduce nonspecific vasodilatation in both anodal and cathodal iontophoresis.
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| 4. |
- Olofsson, Pia, 1962-
(author)
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Experimental studies on Damage Control Surgery and Intraabdominal Hypertension
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Damage control surgery (DCS) offers an alternative to the traditional surgical management of complex or multiple injuries in critically injured patients. If a patient survives the initial phase of DCS, complications may occur, one of these being intraabdominal hypertension (IAH) and it´s potential development into the abdominal compartment syndrome.The indications for DCS have been widened and DCS principles can be applied in situations where time and resources are essential factors. The DCS principles of rapidly controlling intestinal spillage have not been evaluated. The aim of the studies in Papers I and II was to evaluate the principles of spillage control of intestinal contents according to the DCS concept and more specifically the effects of early rapid control of multiple bowel perforations on cardiovascular and pulmonary function compared with conventional small bowel resections in an animal model with abdominal trauma. In Paper I the animal model using anaesthetised pigs included a gunshot wound to the abdomen which caused multiple small bowel injuries. Haemorrhagic shock was combined with the gunshot wound in Paper II. The results presented in Paper I showed a significant reduction in rise in systemic vascular resistance and pulmonary vascular resistance, and a trend towards higher cardiac output and lower oxygen consumption in the bowel ligation group. In Paper II the results show a longer persistence of lactic acidaemia in the bowel ligation group. The aim of the study in Paper III was to assess visceral (intestinal, gastric and renal) microcirculation parallel with central haemodynamics and respiratory function during stepwise increases in intraabdominal pressure. In Paper IV we studied mucosal barrier function and morphology in the small bowel and colon of the pigs which were subjected to IAH. The IAP in anaesthetised pigs was increased stepwise using CO2 inflation, by 10 mm Hg at 10-minute intervals up to 50 mm Hg, and followed by exsufflation (Paper III). The microcirculation was selectively studied using a 4-channel laser Doppler flowmeter (Periflex 5000, Perimed, Sweden). The mucosal tissues were mounted in modified Ussing chambers for assessment of barrier function (E.coli K12 uptake and 51Cr-EDTA permeability) (Paper IV). The results showed that the microcirculation of the small bowel mucosa and colon mucosa was significantly less affected compared to the seromuscular layers. The microcirculation of gastric mucosa, renal cortex and the seromuscular layer of small bowel and colon were significantly reduced with each increase. Cardiac output (CO) decreased significantly at IAP levels above 10 mm Hg and the respiratory function data showed an increasing airway pressure and a concomitant reduction in thoracic compliance. Transmucosal passage of E. coli was increased three-fold in the small bowel after ACS with a significant correlation to the degree of mucosal microcirculatory reperfusion after exsufflation. 51Cr-EDTA permeability was unaffected. Bacterial passage in the colon was unchanged, whereas 51Cr-EDTA permeability after ACS increased by up to 181% of baseline and was correlated to significant histopathological changes in the mucosa.In Paper I we have demonstrated that early rapid control of multiple bowel perforations in a model with moderate shock resulted in less impairment of SVR and PVR than conventional resection and anastomosis. The use of DCS principles, however, had no beneficial effect on cardiovascular function when haemorrhagic shock was combined with abdominal missile trauma (Paper II), on the contrary bowel ligation was followed by more prolonged lactic acidosis than conventional repair. The studies in Paper III and IV indicate that the microcirculation of intestinal mucosa and especially small bowel mucosa seem better preserved in response to intraabdominal hypertension caused by CO2 insufflation than other intraabdominal microvascular beds. The short term ACS in this model caused morphological changes in the intestinal mucosa, and mucosal barrier dysfunction. The response pattern concerning barrier function changes after CO2 insufflation differs between small bowel and colonic mucosa. The small bowel mucosa showed increased bacterial passage, and the colonic mucosa an increase in paracellular permeability and secretory response.
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- Olofsson, Pia, 1962-, et al.
(author)
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The effects of early rapid control of multiple bowel perforations after high-energy trauma to the abdomen : implications for damage control surgery
- 2006
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In: Journal of Trauma. - : Ovid Technologies (Wolters Kluwer Health). - 0022-5282 .- 1529-8809. ; 61:1, s. 185-191
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Journal article (peer-reviewed)abstract
- BACKGROUND: This study evaluates the effects of early rapid control of multiple bowel perforations on cardiovascular and pulmonary function in high-energy traumatic shock compared with conventional small bowel resection anastomosis. METHODS: Fifteen anesthetized pigs, 10 to 12 weeks old, were exposed to a reproducible high-energy trauma and were divided into two groups. In the first group, the resection anastomosis group (RA, n = 8), small-bowel injuries were treated with resection and anastomosis; in the second group, the multiple bowel ligation group (BL, n = 7), small-bowel injuries were treated by resection and ligation. Repeated measurement analysis of variance was used to study the within group change overtime, the between group difference, and the interaction between them. Mean outcome measures were intravascular pressures, cardiac output, vascular resistance, lactic acid, and blood gases. RESULTS: The high-energy injuries caused traumatic shock in both groups with reduced cardiac output (p < 0.001) and lactic acidemia (p < 0.001). The BL group had a trend for higher cardiac output (p = 0.06). The rise in systemic and pulmonary vascular resistance was significantly reduced in the BL group compared with the RA group (p < 0.05). The BL group had a strong trend for higher oxygen extraction ratio (p = 0.06). There was a trend for less oxygen consumption in the BL group (p = 0.07). There was no difference in the lactic acidemia between the two groups. CONCLUSIONS: Early rapid control of multiple bowel perforations after high-energy trauma resulted in less impairment of cardiovascular function than conventional resection anastomosis of the bowel.
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