| 1. |
- Ericsson, Iréne, et al.
(författare)
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KUD- a scale for clinical evaluation of moderate-to-severe dementia
- 2011
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Ingår i: Journal of Clinical Nursing. - : Wiley. - 0962-1067 .- 1365-2702. ; 20:11-12, s. 1542-1552
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Tidskriftsartikel (refereegranskat)abstract
- Aim. To develop a test of cognitive performance in persons with moderate-to-severe dementia.Background. Various instruments are used to assess the course of dementia and to evaluate treatments in persons with dementia. Most neuropsychological assessments are inappropriate for measuring cognitive abilities in persons with severe dementia, because these persons perform at floor level in such measurements.Design. A cross-sectional research design.Methods. The test (Clinical Evaluation of Moderate-to-Severe Dementia; Swedish acronym: KUD) was developed from a pool of 25 test items with the final KUD consisting of 15 items. Reliability and validity were established using 220 subjects (with various dementia diagnoses) with scores of Mini-Mental State Examination between 0–20. Approximately two weeks after the first test, 116 of the original 220 subjects were retested.Results. A factor analysis with the 15-item scale revealed an interaction factor comprising three items and a cognitive performance factor with 12 items. The internal consistence reliability was 0·93 for the KUD (Cronbach’s alpha). Test–retest reliability was also high (0·92) and correlation between the KUD and the MMSE (≤20) was high (r = 0·80).Conclusion. The KUD seems to be a valid, reliable performance-based assessment scale for measuring cognitive performance in persons with MMSE score below 12 or 15 points.Relevance to clinical practice. It is of outmost interest that cognitive performance can be easily followed for persons with moderate-to-severe dementia in, for example, drug therapies and other therapies, but also in terms of treatment of and support to the person based on his or her abilities.
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| 2. |
- Fahlkrans, Johan, 1980-, et al.
(författare)
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Gas Quench Rate after Low Pressure Carburizing and its Influence on Fatigue Properties of Gears
- 2013
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Ingår i: HTM - Journal of Heat Treatment and Materials. - : Carl Hanser Verlag GmbH. - 1867-2493 .- 2194-1831. ; 68:6, s. 239-245
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Tidskriftsartikel (refereegranskat)abstract
- Process modifications of the gas quench sequence for low pressure carburized gears can increase the performance of up to 22 %, compared to direct gas quenching. Several test series were made with different interruptions of the gas quenching sequence, near the martensite start temperature Ms. The quench interruption resulted in an increase in magnitude of compressive residual stress which was attributed to temperature homogenization and rearrangement of local stresses. The increased fatigue strength was a result of the combination of enhancement of the compressive residual stress state, and of mechanical stabilization of austenite.
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| 3. |
- Fahlkrans, Johan, 1980-, et al.
(författare)
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Influence of tempering on contact fatigue
- 2011
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Ingår i: International Journal of Microstructure and Materials Properties. - 1741-8410 .- 1741-8429. ; 6:6, s. 465-478
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Tidskriftsartikel (refereegranskat)abstract
- Most components are tempered after heat treatment operations such as case hardening or induction hardening. The common opinion is that the martensitic structure after heat treatment is too brittle and tempering is necessary to increase toughness.Tempering is an additional operation which leads to increased costs by energy, handling, and investments. Eliminating tempering from the heat treatment process leads to increased productivity, energy savings, and lowered environmental impact.Two carburised steels, Ovako 253A (?EN 22NiCrMo12-5F mod. A) and EN 20NiCrMo2 (SAE 8620, SS2506), were tested for contact fatigue resistance in a roller to roller rig. The tested samples were characterised with respect to amount of fatigue damage, residual stress, amount of retained austenite and hardness. The objective was to determine if tempering is always necessary after a heat treatment operation.The contact fatigue tests show that tempering results in lower contact fatigue resistance. Further, fatigue cracks were found to have initiated in different ways between tempered and untempered steel.
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| 4. |
- Fahlkrans, Johan, 1980-, et al.
(författare)
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Straightening of induction hardened shats-inluence on fatigue strength and residual stress
- 2012
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Ingår i: HTM - Haerterei-Technische Mitteilungen. - : Carl Hanser Verlag. - 0341-101X. ; 67:3, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- Straightening of distorted components ater heat treatment is oten a necessary operation. he straightening operation leads to local plastic deformation, which is afecting the residual stress state, the hardness, and ultimately the fatigue strength of the component. he present study evaluates the inluence of a straightening operation on fatigue strength and on the residual stress state of induction hardened shats of steel EN 42CrMo4. A simpliied FEM model was formulated. he model showed that the residual stress state was asymmetric along the circumference of a straightened shat. Fatigue testing was performed in a three point bending and showed that the fatigue strength was reduced by up to some 20 % by heavy straightening. A fracture mechanics model for fatigue crack growth and arrest was developed. he model could be used to predict the fatigue strength of a straightened shat provided that the residual stress state was known.
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| 5. |
- Frisk, Karin, et al.
(författare)
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Compound materials by PM-HIP
- 2014
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Ingår i: Powder Metallurgy. - 0032-5899 .- 1743-2901. ; 57:5, s. 341-347
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Tidskriftsartikel (refereegranskat)abstract
- There are many applications where compound materials can be of interest, for example when different properties are needed in different parts of a component. Compound materials can be produced by hot isostatic pressing (HIP) of powder metallurgical materials. One aspect that should be considered in the design is the quality of the interface between the two different material compositions. Diffusion during HIP can cause formation of brittle phases in the interface or deteriorate properties by diffusion of alloying elements. The present work shows results from a study where different steel types were joined (quench and temper steel/air hardening steel/bearing steel with a tool steel/corrosion resistant martensitic steel). The evaluation was performed by computational predictions and by small scale HIP experiments that were evaluated by microstructure analysis and chemical analysis. © 2014 Institute of Materials, Minerals and Mining.
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| 6. |
- Haglund, Sven
(författare)
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Fatigue properties of Austempered Ductile Iron (ADI)
- 2011
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Rapport (refereegranskat)abstract
- In this work ADI-iron has been studied with a main focus on fatigue properties. ADI is a rather new set of materials with in many cases improved properties as compared to standard iron, and may in some cases even replace wrought materials. The composition range, as well as heat treatment parameters is rather narrow so a careful production control is necessary. In the experimental part of this work the fatigue properties of an ADI treated iron (austenetised at 880°C and ADI treated at 400°C) has been tested on hour glass shaped specimens. The material exhibited a fatigue strength at 106 cycles of ~480 MPa (stress range, R=0), see figure A2. The fatigue initiation was controlled by defects, i.e. pores, in the material.
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| 7. |
- Haglund, Sofie, et al.
(författare)
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Gene Expression and Thiopurine Metabolite Profiling in Inflammatory Bowel Disease : Novel Clues to Drug Targets and Disease Mechanisms?
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- Background and AimsThiopurines are effective to induce and maintain remission in inflammatory bowel disease (IBD). The methyl thioinosine monophosphate (meTIMP)/6-thioguanine nucleotide (6-TGN) concentration ratio has been associated with drug efficacy. Here we explored the molecular basis of differences in metabolite profiles and in relation to disease activity.MethodsTranscriptional profiles in blood samples from an exploratory IBD-patient cohort (n = 21) with a normal thiopurine S-methyltransferase phenotype and meTIMP/6-TGN ratios >20, 10.0–14.0 and ≤4, respectively, were assessed by hybridization to microarrays. Results were further evaluated with RT qPCR in an expanded patient cohort (n = 54). Additionally, 30 purine/thiopurine related genes were analysed separately.ResultsAmong 17 genes identified by microarray-screening, there were none with a known relationship to pathways of purines/thiopurines. For nine of them a correlation between expression level and the concentration of meTIMP, 6-TGN and/or the meTIMP/6-TGN ratio was confirmed in the expanded cohort. Nine of the purine/thiopurine related genes were identified in the expanded cohort to correlate with meTIMP, 6-TGN and/or the meTIMP/6-TGN ratio. However, only small differences in gene expression levels were noticed over the three different metabolite profiles. The expression levels of four genes identified by microarray screening (PLCB2, HVCN1, CTSS, and DEF8) and one purine/thiopurine related gene (NME6) correlated significantly with the clinical activity of Crohn’s disease. Additionally, 16 of the genes from the expanded patient cohort interacted in networks with candidate IBD susceptibility genes.ConclusionsSeventeen of the 18 genes which correlated with thiopurine metabolite levels also correlated with disease activity or participated in networks with candidate IBD susceptibility genes involved in processes such as purine metabolism, cytokine signaling, and functioning of invariant natural killer T cells, T cells and B cells. Therefore, we conclude that the identified genes to a large extent are related to drug targets and disease mechanisms of IBD.
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| 8. |
- Haglund, Sofie
(författare)
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Interindividual differences in thiopurine metabolism : studies with focus on inflammatory bowel disease
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thiopurines, 6-mercaptopurine and its prodrug azathioprine, are used in the treatment of inflammatory bowel disease, ulcerative colitis and Crohn´s disease. The main active metabolites are the phosphorylated thioguanine nucleotides (6-TGNs) and methylated thioinosine monophosphate (meTIMP). Both groups contribute to the immunomodulatory effects. About 30-40% of patients fail to benefit from thiopurine treatment. A well-known cause of adverse reactions is decreased or absent thiopurine S-methyltransferase (TPMT) activity. Low TPMT activity is inherited as an autosomal codominant recessive trait and is present in approximately 10% of the population. Although several clinical issues can be solved from determination of TPMT activity, there are cases where it is not possible. In Sweden approximately 25% of IBD-patients display suboptimal 6-TGN concentrations and unexpectedly high concentrations of meTIMP despite a normal TPMT activity. A high meTIMP/6-TGN concentration ratio has been associated with both unresponsiveness to therapy and emergence of adverse reactions. Inosine 5’-monophosphate dehydrogenase (IMPDH) may constitute a candidate gene to explain this metabolite profile, as it is strategically positioned in the metabolic pathway of thiopurines where it competes with TPMT for their common substrate 6-TIMP.In paper I a pyrosequencing method was developed for genotyping of at that time all known genetic variants of TPMT. The concordance between genotype and phenotype in 30 individuals was 93%. The allele frequencies of TPMT*3A, *3B, *3C and *2 in a Swedish background population (n=800) were in agreement with those in other Caucasian or European populations. In Paper II-IV we explored the molecular basis of different metabolite profiles, i.e. low, normal and high meTIMP/6-TGN concentration ratios. The activity of IMPDH was measured in mononuclear cells (MNC). Patients with high metabolite ratios had lower IMPDH activity than patients with normal or low ratios, explained by an inverse correlation to red blood cells concentration of meTIMP. No correlation to 6-TGN was observed. Downregulation of IMPDH activity in HEK293 cells with genetically engineered TPMT activity was associated with an increase in meTIMP, but unexpectedly also of 6-TGN, irrespective of the TPMT status. These results suggest effects of pharmacogenes other than TPMT and IMPDH. A whole genome expression analysis was performed, (1) to identify new candidate genes that could explain differences in metabolite profiles, and (2) to study genes with known associations to the metabolic pathway of (thio)purines. The whole genome expression analysis did not identify any significant group differences. In analysis of the thiopurine related genes, three clusters of co-regulated genes were defined. A co-operation between expression levels of SLC29A1 and NT5E in explaining the meTIMP/6-TGN concentration ratio was observed, and individually SLC29A1 and NT5E correlated to 6-TGN and meTIMP, respectively.Pysosequencing is a convenient and flexible method which is now run in parallel to phenotyping in our laboratory. Our results also illustrate the complexity of the thiopurine metabolism and suggest that differences between metabolite profiles are explained either by interactions between several genes, each with a small contribution, or at the post-transcriptional level. Search for more precise tools to explain differences in metabolite profiles is needed. Furthermore, in order to investigate small effects it is necessary to analyse metabolite concentrations and gene expression levels, as well as enzyme activities in the target cells of therapy (MNC).
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| 9. |
- Haglund, Sven, et al.
(författare)
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Interrupted quenching during the martensite transformation in steels 100CrMn6 and 20NiCrMo7
- 2011
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Rapport (refereegranskat)abstract
- In this work the hypothesis “All quenching of steel components should be interrupted at ~50% martensite formed in order to achieve better fatigue performance” has been tested. The results are very positive. The effect of slower quenching seems to be generic, i.e. valid for different steels and different heat treating processes. It has now been studied on three steels, three heat treatment methods and three quenching method (in this and previous projects) and it can be concluded that in all cases slower quenching gave better fatigue resistance when no HTTPstructures were formed in the surface. HTTP-structures are believed to act as a low strength skin neutralising the increased fatigue resistance from slow cooling. One important fact that brings us to the conclusion that the effect is generic was that in all cases dilatometer measurements with slower cooling gave less expansion during the martensite transformation, indicating more retained austenite, which would explain the better fatigue resistance by crack arrest from expansion of transforming retained austenite during fatigue. EBSD measurements have shown that the martensite laths were larger in the slower cooled samples and indicate more retained austenite in slower cooled samples. No difference in retained austenite content could be measured by x-ray, not on the fatigue test bars or in the dilatometer test bars. The measurement error in the x-ray method is likely to be too large to resolve the smalldifferences between different coolingrats. The effect of slow cooling on residualstresses remains unexplained. Smallerdilation during phase transformation inthe surface is thought to yield lowercompressive stresses, not higher asmeasured on the test bars.
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| 10. |
- Haglund, Sven
(författare)
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Modelling and prediction of fatigue properties of tool steels based on defects, geometry and surface condition
- 2010
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Ingår i: Proceedings of the World Powder Metallurgy Congress and Exhibition, World PM 2010. - : European Powder Metallurgy Association (EPMA). - 9781899072194
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Konferensbidrag (refereegranskat)abstract
- During a period of the last ten years a new model has been developed at SwereaKIMAB that is able to predict the fatigue properties of tool steels based on measured carbide and inclusion distributions. The model has been programmed into software named FATSIMR. Lately, effects such as notch effect and surface roughness have been added to the model enabling it to predict the fatigue properties of actual tool designs. In the presence of a notch the software takes into account the decrease in stressed volume and thereby the decreased probability of a defect present in the most stressed part. As an upper bound the software estimates the intrinsic fatigue strength of the steel matrix. In this presentation the model is presented and examples are given on how the software can be applied on various high stressed tooling components.
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