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| 2. |
- Agevall, Ola
(författare)
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Weber, kausaliteten och oändligheten
- 1994
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Ingår i: Sociologisk Forskning. - : Sveriges Sociologförbund. - 0038-0342. ; 31:3, s. 57-75
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Ahrenstedt, Örjan, et al.
(författare)
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Enhanced local production of the complement components in the small intestine in Crohn's disease
- 1990
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 322, s. 1345-1349
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Tidskriftsartikel (refereegranskat)abstract
- There is evidence that complement components may be formed locally in inflammatory lesions containing monocytes and macrophages. To investigate the role of complement in Crohn's disease we measured jejunal-fluid concentrations of the complement components C4, C3, and factor B by perfusion of a closed segment of the jejunum in 22 patients with Crohn's disease thought to be limited to the terminal ileum.The mean (±SEM) jejunal-fluid C4 concentration was 2.0±0.3 mg per liter, significantly higher than the mean level in 35 healthy controls (0.7±0.1 mg per liter; P<0.001). The mean C3 concentration was 1.0±0.1 mg per liter in the patients and 0.7±0.1 mg per liter in the controls (P<0.05). The factor B levels were similar in the two groups. Calculated rates of intestinal secretion of these components showed differences of the same magnitude. Leakage of protein from plasma was not increased. The jejunal-fluid serum ratios of these complement proteins indicated that their appearance in the lumen of the jejunum was due at least in part to local mucosal synthesis. The increased jejunal secretion of C4, but not C3 or factor B, paralleled the clinical activity of Crohn's disease. Values were normal in first-degree relatives of the patients (n = 13), patients with celiac disease (n = 8), and patients with ulcerative colitis (n = 4).We conclude that increased secretion of complement by clinically unaffected jejunal tissue in patients with Crohn's disease reflects the systemic nature of this disorder and may be due to the stimulated synthesis of complement by activated intestinal monocytes and macrophages.
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| 4. |
- Akimov, D., et al.
(författare)
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Physics with WASA and PROMICE
- 1994
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Ingår i: Physics with GeV-particle beams, Juelich 1994. ; , s. 519-530
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Konferensbidrag (refereegranskat)
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| 6. |
- Al-Najjar, Basim, 1954-
(författare)
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On the selection of condition based maintenance for mechanical systems
- 1991
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Ingår i: Operational reliability and systematic maintenance. - London : Elsevier Applied Science. - 1851666125 ; , s. 153-175
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Bokkapitel (refereegranskat)abstract
- The requirements for increased plant productivity and safety, and reduced maintenance costs, have led to an increasing interest in methods for condition monitoring of mechanical systems. In the literature on Reliability-Centred Maintenance, RCM, the selection of a maintenance technique is mainly carried out on the level of system failure modes. Also, distinguishing criteria such as the long run average cost per unit time are not modelled see for example, Nowlan et al. (1978). In this study, a summary of three papers, Al-Najjar (1990a, b& c), component failure causes and failure mechanisms are involved in the selection problem, and a long run average cost per unit time is modelled. In chapter 2, the identification of significant components is described. State-changes of a component are discussed in chapter 3. New classifications of failures, monitoring parameters and monitoring techniques are proposed in chapters 2 and 4, respectively. Data sampling and analysis are discussed in chapter 4. The cumulative sum chart is proposed as a technique to reduce the fluctuation in monitoring parameter value. In chapter 5, the selection of a cost-effective policy is carried out based on economical and non-economical distinguishing criteria. Chapters 1 to 5 summarise Al-Najjar (1990a). Modelling of a condition dependent failure rate function is discussed in chapter 6, which the summary of Al-Najjar (1990b). Chapter 7 is addressed to the problem of selecting a cost-effective monitoring technique based on observational data. To carry out the selection, we suggest the use of a generalization of a method, related to the Total Time on Test, TTT-plot, introduced by Bergman (1977). Also, a graphical method to estimate the threshold level of a monitoring parameter when using a cost-effective technique is proposed, see also Al-Najjar (1990c).
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| 7. |
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| 8. |
- Al-Najjar, Basim, 1954-
(författare)
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Some problems on the selection of a condition based maintenance technique for mechanical systems
- 1990
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the first paper we focused mainly on establishing a sequential method for the selection of a maintenance technique for mechanical systems. The selection problem is studied for the components having considerable consequences and a non-negligible failure intensity. Identification of these components based on their failure mechanisms and failure causes is discussed and a modified version of the usual Failure Modes, Effects and Criticality Analysis, FMECA is suggested. A cumulative sum chart is proposed to identify a replacement time. This is explained by way of two examples. In order to run cost per unit time is proposed. The selection of a maintenance technique based on the intrinsic information of monitoring parameters is introduced.Ability of a monitoring parameter in predicting failures, can be described as a probability of failure in the future conditionally on the current value of a model monitoring parameter. Thus, the second paper is focused on introducing a model relating a condition dependent failure rate to a component condition. For the selection of a cost-effective technique a modified proportional hazards model, PHM, is proposed. The modified model is able to reveal the effect of observing monitoring parameters and operating conditions on failure rate function.A graphical method, based on a Generalized Total Time on Test, a GTTT- plot, for the selection of a cost-effective technique is proposed in the third paper. Also, a graphical method to estimate the threshold level for a cost-effective technique based on the same concept is suggested. These methods are illustrated by way of an example.
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| 9. |
- Albinsson, Gunilla, et al.
(författare)
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Effekter och kostnader av total höftledsplastik i Karlskrona och Karlshamn
- 1991
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med projektet är att mäta hälsoeffekter av total höftledsplastik med hjälp av hälsoindex och höftindex, att göra en beräkning av kostnaderna för total höftledsplastik inom hälso- och sjukvårdssystemets olika delar, samt att analysera skillnader i resursförbrukning vid Karlskrona och Karlshamns lasarett. Hälsoindexen Rosser, Sickness Impact Profile (SIP) och Euroqol har använts och visar förbättrat hälsoindex 6 månader efter operationen. Höftindexen Charnley, Andersson-Möller/Nielsen och Harris har också testats. Avgörande skillnader mellan höft- och hälsoindex påvisas ej. Kostnaden för ett ingrepp är ca 60 000 kr. Variationer i kostnader mellan olika kliniker kan förklaras med olika behandlingsrutiner.
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