| 1. |
- Abedini, M., et al.
(författare)
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Customer credit scoring using a hybrid data mining approach
- 2016
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Ingår i: Kybernetes. - 0368-492X .- 1758-7883. ; 45:10, s. 1576-1588
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: A crucial decision in financial services is how to classify credit or loan applicants into good and bad applicants. The purpose of this paper is to propose a four-stage hybrid data mining approach to support the decision-making process. Design/methodology/approach: The approach is inspired by the bagging ensemble learning method and proposes a new voting method, namely two-level majority voting in the last stage. First some training subsets are generated. Then some different base classifiers are tuned and afterward some ensemble methods are applied to strengthen tuned classifiers. Finally, two-level majority voting schemes help the approach to achieve more accuracy. Findings: A comparison of results shows the proposed model outperforms powerful single classifiers such as multilayer perceptron (MLP), support vector machine, logistic regression (LR). In addition, it is more accurate than ensemble learning methods such as bagging-LR or rotation forest (RF)-MLP. The model outperforms single classifiers in terms of type I and II errors; it is close to some ensemble approaches such as bagging-LR and RF-MLP but fails to outperform them in terms of type I and II errors. Moreover, majority voting in the final stage provides more reliable results. Practical implications: The study concludes the approach would be beneficial for banks, credit card companies and other credit provider organisations. Originality/value: A novel four stages hybrid approach inspired by bagging ensemble method proposed. Moreover the two-level majority voting in two different schemes in the last stage provides more accuracy. An integrated evaluation criterion for classification errors provides an enhanced insight for error comparisons.
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| 2. |
- Abedini, Sadollah, et al.
(författare)
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Asymmetrical dimethylarginine is associated with renal and cardiovascular outcomes and all-cause mortality in renal transplant recipients
- 2010
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Ingår i: Kidney International. - : Elsevier BV. - 0085-2538 .- 1523-1755. ; 77:1, s. 44-50
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Tidskriftsartikel (refereegranskat)abstract
- Increased plasma levels of asymmetric dimethylarginine (ADMA) are associated with endothelial dysfunction and predict the progression to dialysis and death in patients with chronic kidney disease. The effects of these increased ADMA levels in renal transplant recipients, however, are unknown. We used the data from ALERT, a randomized, double-blind, placebo-controlled study of the effect of fluvastatin on cardiovascular and renal outcomes in 2102 renal transplant recipients with stable graft function on enrollment. Patients who were initially randomized to fluvastatin or placebo in the 5- to 6-year trial were offered open-label fluvastatin in a 2-year extension of the original study. After adjustment for baseline values for established factors in this post hoc analysis, ADMA was found to be a significant risk factor for graft failure or doubling of serum creatinine (hazard ratio 2.78), major cardiac events (hazard ratio 2.61), cerebrovascular events (hazard ratio 6.63), and all-cause mortality (hazard ratio 4.87). In this trial extension, the number of end points increased with increasing quartiles of plasma ADMA levels. All end points were significantly increased in the fourth compared to the first quartile. Our study shows that elevated plasma levels of ADMA are associated with increased morbidity, mortality, and the deterioration of graft function in renal transplant recipients.
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| 3. |
- Abedini, Sadollah, et al.
(författare)
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Cerebrovascular events in renal transplant recipients
- 2009
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Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 87:1, s. 112-7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The incidence of stroke and risk factors for different subtypes of cerebrovascular (CBV) events in renal transplant recipients have not been examined in any large prospective controlled trial. METHODS: The Assessment of Lescol in Renal Transplantation was a randomized, double-blind, placebo-controlled study of the effect of fluvastatin (40-80 mg) daily on cardiovascular, and renal outcomes in renal transplant recipients. Patients initially randomized to fluvastatin or placebo in the 5 to 6 year trial was offered open-label fluvastatin in a 2-year extension to the original study. We investigated the incidence of stroke and risk factors for ischemic and hemorrhagic CBV events in 2102 renal graft recipients participating in the Assessment of Lescol in Renal Transplantation core and extension trial with a mean follow-up of 6.7 years. RESULTS: The incidence and type of CBV events did not differ between the lipid lowering arm and the placebo arm. A total of 184 (8.8%, 95% confidence interval 4.6-12.9) of 2102 patients experienced a CBV event during follow-up, corresponding to an incidence of 1.3% CBV event per year. The mortality for patients experiencing a hemorrhagic stroke was 48% (13 of 27), whereas the mortality for ischemic strokes was 6.0% (8 of 133). Diabetes mellitus, previous CBV event, age, and serum creatinine were independent risk factors for cerebral ischemic events. The risk of a hemorrhagic cerebral event was increased by diabetes mellitus, polycystic kidney disease, left ventricular hypertrophy, and systolic blood pressure. INTERPRETATION: Risk factors for CBV events in renal transplant recipients differ according to subtype.
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| 4. |
- Bugaytsova, Zhanna, et al.
(författare)
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Localization, purification and properties of a tetrathionate hydrolase from Acidithiobacillus caldus
- 2004
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Ingår i: European Journal of Biochemistry. - Hoboken : Wiley-Blackwell. - 0014-2956 .- 1432-1033. ; 271:2, s. 272-280
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Tidskriftsartikel (refereegranskat)abstract
- The moderately thermophilic bacterium Acidithiobacillus caldus is found in bacterial populations in many bioleaching operations throughout the world. This bacterium oxidizes elemental sulfur and other reduced inorganic sulfur compounds as the sole source of energy. The purpose of this study was to purify and characterize the tetrathionate hydrolase of A. caldus. The enzyme was purified 16.7-fold by one step chromatography using a SP Sepharose column. The purified enzyme resolved into a single band in 10% polyacrylamide gel, both under denaturing and native conditions. Its homogeneity was confirmed by N-terminal amino acid sequencing. Tetrathionate hydrolase was shown to be a homodimer with a molecular mass of 103 kDa (composed from two 52 kDa monomers). The purified enzyme had optimum activity at pH 3.0 and 40 degreesC and an isoelectric point of 9.8. The periplasmic localization of the enzyme was determined by differential fractionation of A. caldus cells. Detected products of the tetrathionate hydrolase reaction were thiosulfate and pentathionate as confirmed by RP-HPLC analysis. The activity of the purified enzyme was drastically enhanced by divalent metal ions.
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| 5. |
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| 6. |
- Dahlbäck, Olof, 1944-
(författare)
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Risktagande
- 1978
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)
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| 7. |
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| 8. |
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| 9. |
- Gerdtham, Ulf-Göran, et al.
(författare)
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The impact of user charges on the consumption of drugs : Empirical evidence and economic implications
- 1996
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Ingår i: PharmacoEconomics. - : Springer Nature. - 1179-2027 .- 1170-7690. ; 9:6, s. 478-483
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Tidskriftsartikel (refereegranskat)abstract
- Expenditure on drugs is increasing rapidly in many countries, and this has led to increased interest in measures to contain drug expenditure. One measure that has been discussed is to increase user charges for prescription drugs. In this article, we consider whether or not raising user charges decreases the consumption of drugs. We also discuss how to judge if increased user charges for drugs are desirable from an economic viewpoint. We conclude that the decision to increase user charges for prescription drugs should not be viewed as an issue of cost containment, but as a matter of balancing the societal costs against the societal benefits of increased user charges.
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| 10. |
- Gerdtham, Ulf-G., et al.
(författare)
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Trait self-control, exercise and exercise ambition : Evidence from a healthy, adult population
- 2020
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Ingår i: Psychology, Health & Medicine. - : Informa UK Limited. - 1354-8506 .- 1465-3966. ; 25:5, s. 583-592
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Tidskriftsartikel (refereegranskat)abstract
- This study explores if self-control predicts exercise ambition and actual exercise, and if exercise ambition predicts actual exercise. Members and guests at a not-for-profit sports club were invited to participate. 264 individuals completed a self-reported (Self-Control Scale) measure of self-control, and responded to questions about actual exercise as well as exercise ambition prior to their workout. Main Outcome Measures are exercise ambition, actual exercise, and the difference between them. We find that trait self-control predicts both actual exercise and exercise ambition. Exercise ambition also predicts actual exercise. The results suggest a path from self-control, via exercise ambition, to actual exercise. Individuals with relatively low self-control might benefit from some aid in setting goals for their workouts and committing to exercise.
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| 11. |
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| 12. |
- Holcik, J., et al.
(författare)
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A deadly pandemic [in Czech]
- 2002
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Ingår i: Casopis Lekaru Ceskych. ; 141:21, s. 659-662
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Tidskriftsartikel (refereegranskat)
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| 13. |
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| 14. |
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| 15. |
- Holmdahl, Meirav
(författare)
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Dendritic cell presentation of type II collagen
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Type II collagen (CII) is the main protein component of cartilage and immune recognition of CII plays a critical role for the development of collagen induced arthritis (CIA), a widely used animal model for rheumatoid arthritis (RA). Antigen presentation is an important requirement for the immune response, the more efficient presentation of the antigen the better tolerance will be induced and thereby protect against arthritis. Out of different professional antigen presenting cells (APCs), Langerhans cells (LCs), a subtype of dendritic cells, have been shown to poorly present CII compared to other antigens tested, but also compared to other APCs like B cells and macrophages. The inability to present CII is an exception from the rule that dendritic cells (DCs) are efficient in antigen presentation and subsequently in priming of naive T cells. This incompetence could however be overcome by treating with cysteine protease inhibitors, inhibiting certain cathepsins important for antigen degradation of the CII peptide in endosomes. Cystatin C, a natural occurring inhibitor of cathepsin S, is expressed in immature DCs. Cystatin C deficient mice were back-crossed into arthritis susceptible B10.Q mouse strain, surprisingly, with no difference in CII presentation between different genotypes and APCs in vitro. However, upon CII immunization, homozygous cystatin C deficient mice had a more severe arthritis ans disease incidence compared to wild-type littermates. The anti-CII antibody titers and delayed type hypersensitivity response (DTH) were also increased in the cystatin C deficient mice compared to the wild-type controls. The interpretation of our data favours antigen presentation being the targe cells for cystatin C activity. The present observation that the NOD.Q strain, which is resistant ti CIA in spite of expressing the arthritis susceptibel MHC class II H2-Aq allele, in fact have LCs which do present CII provide possibility to genetically dissect the phenomena. The major loci located on chromosome 2 and 13 were found to control LC presentation of CII. Of these two loci ine of them strongly correlated with CIA, an observation confirmed with the help of the Cia2 congenic mouse. Thus within this limited region there are one or several genes that affect LC CII presentaion and possibly these could be same as the genes controlling CIA.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Holmdahl, Rikard
(författare)
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Aire-ing self antigen variability and tolerance.
- 2007
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Ingår i: European Journal of Immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 37:3, s. 598-601
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Tidskriftsartikel (refereegranskat)abstract
- Positional cloning of the underlying genes for the rare syndrome autoimmune polyendocrinopathy candidadiasis extrodermal dystrophy (APECED) opened a new venue of research on the role of central tolerance in autoimmunity. The associated autoimmune regulator gene (AIRE), was found to be expressed in medullary thymus epithelial cells (mTEC) in both man and mice, and to control promiscuous expression of sets of self antigens. The lack of AIRE in both mice and man led to the development of a quite specific, but also an inter-individual variable, set of autoimmune and infectious diseases. An article in this issue of the European Journal of Immunology demonstrates that several autoantigens controlled by AIRE are variably expressed in different human individuals. Most importantly it is shown that carriers of the type 1 diabetes (T1D) associated locus IDDM2 show lower expression of insulin in mTEC, as controlled by AIRE. The genetic variability of autoantigen expression in the thymus thus seems to determine the variable predisposition to autoimmunity.
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| 20. |
- Holmdahl, Rikard, et al.
(författare)
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Arthritis induced in rats with non-immunogenic adjuvants as models for rheumatoid arthritis
- 2001
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Ingår i: Immunological Reviews. - : Wiley. - 1600-065X .- 0105-2896. ; 184
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Forskningsöversikt (refereegranskat)abstract
- Rat models are useful for studies of the pathogenesis of rheumatoid arthritis (RA) since rats are extraordinarily sensitive to induction of arthritis with adjuvants. Injection of not only the classical complete Freund's adjuvant but also mineral oil without mycobacteria and pure adjuvants such as pristane and squalene, induce severe arthritis in many rat strains. Models like pristane-induced arthritis in rats are optimal models for RA since they fulfill the RA criteria including a chronic relapsing disease course. Arthritogenic adjuvants like pristane, avridine, squalene and mineral oil are not immunogenic since they do not contain major histocompatibility complex (MHC) binding peptides. Nevertheless, the diseases are MHC-associated and dependent on the activation of alphabetaTCR (T-cell receptor)-expressing T cells. However, it has not been possible to link the immune response to joint antigens or other endogenous components although immunization with various cartilage proteins induce arthritis but with different pathogeneses. To unravel the mechanisms behind adjuvant-induced arthritis, a disease-oriented genetic approach is optimal. Several loci that control onset of arthritis, severity and chronicity of the disease have been identified in genetic crosses and most of these have been confirmed in congenic strains. In addition, many of these loci are found in other autoimmune models in the rat as well as associated with arthritis in mice and humans.
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| 21. |
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| 22. |
- Janciauskiene, Sabina, et al.
(författare)
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Secreted leukocyte protease inhibitor is present in aqueous humours from cataracts and other eye pathologies.
- 2006
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835. ; 82:3, s. 505-511
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies identified serine, cysteine and metalloproteases in normal aqueous humours (AH) and suggested that a balance between proteases and their inhibitors may play a role in the modulation of the AH outflow. We aimed to determine whether secretory leukocyte protease inhibitor (SLPI), a serine protease inhibitor, is present in AH of patients with cataract and other eye pathologies. AH was collected from 117 cataract patients of which 55 were diagnosed with more when one eye disease: cataract only (n = 62), pseudoexfoliation (PEX) (n = 26), glaucoma (n = 6), diabetes retinopathy (n = 4), iritis-uveitis (n = 4) and macular degeneration (n = 28). The total protein in AH was determined by a Bradford assay and SLPI was analyzed by Western blot and ELISA methods. The average concentration of total protein and SLPI in AH samples was 160 +/- 15 mu g/ml (n = 117, +/- SEM) and 500 +/- 94 pg/ml (n = 105), respectively. The cataract patients with additional eye disease(s) showed higher protein levels (201 + 35 mu g/ml) than cataract (controls) (128 31 pg/ml), P < 0.01. It is noteworthy that no correlation was found between SLPI and the total protein concentrations in AH, but SLPI was positively correlated with age (r = 0.2, P < 0.05). No statistical difference in SLPI levels was found between controls (cataract) and other pathologies, while patients with iritis/uveitis had higher SLPI levels compared to those with diabetes (P < 0.05). We show here for the first time that SLPI is present in AH and may play a role as well as serve as a marker in pathological states. (c) 2005 Elsevier Ltd. All rights reserved.
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| 23. |
- Jancke, Georg, 1970-
(författare)
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Aspects of Recurrence and Progression in Ta/T1 Urinary Bladder Cancer
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aims: To evaluate different aspects of recurrence and, when appropriate, progression in primary Ta/T1 urinary bladder cancer.Patients and methods: All evaluable patients diagnosed with primary Ta/T1 urinary bladder cancer in Linköping and Norrköping between 1992 and 2007 were included prospectively in the study cohort. Histopathology results were classified according to the TNM system and were reviewed by a reference pathologist using the WHO 1999 criteria (except in the studies reported in Papers I and IV). Risk factors for local recurrence were evaluated using data from the period 1992–2001 (Paper I). Tumour size (Paper II) and bladder wash cytology (Paper III) at primary diagnosis were assessed regarding the impact on recurrence and progression, and tumour presence in the marginal resection in primary and recurrent Ta/T1 bladder cancer was investigated considering effects on recurrence in patients treated between 2001 and 2010 (Paper IV). Furthermore, surgical experience measured as training status (resident or specialist) and surgical volume (both during the study period and lifetime) were analysed regarding their influence on recurrence and progression (Paper V).Results: Tumour size > 30 mm (p < 0.001) and multiplicity (p = 0.021) were significantly associated with local recurrence (Paper I). Tumour sizes 16–30 mm and > 30 mm were correlated with recurrence (p = 0.003 and p < 0.001, respectively) but not with progression (Paper II). High-grade malignant bladder wash cytology proved to be predictive of both recurrence (p < 0.001) and progression (p = 0.036) as was shown in Paper III. A tumour-positive marginal resection was related to overall (p < 0.001) and local (p < 0.001) recurrence (Paper IV). Transurethral resection of bladder tumours performed by residents was associated with recurrence (p = 0.004) but not with progression. No differences in relation to either recurrence or progression were found for the surgical volume approach at the chosen cut-offs (Paper V).Conclusions: The present studies identified new risk factors for recurrence (tumours > 15 mm, high-grade bladder wash cytology at diagnosis, tumour-positive marginal resection, and surgery performed by residents) and progression (local recurrence and high-grade malignant bladder wash cytology at diagnosis), which in the future may be integrated into follow-up schedules or risk profiles for patients with Ta/T1 urinary bladder cancer.
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| 24. |
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| 25. |
- Johansson, Jens, et al.
(författare)
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Investigations into the pitting behaviour of different gear lubricants by using a rolling four ball test configuration
- 2011
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Konferensbidrag (refereegranskat)abstract
- Vehicle manufacturers today face increasing demands to produce fuel efficient vehicles. If this is to be successfully achieved, the reduction of energy losses is vital [1]. One approach to loss reduction is to use lower viscosity trans mission fluids to reduce splash (churning) losses in the drive-train. However, this introduces potential problems in regard to the durability of machine components due to reduction in oil film thickness [2 ]. As regards gear transmission, the durability is mainly related to the formation of micropits on parts of gears where sliding is high, which later lead to pitting damage. The formation of micropits is due to surface stress which can be reduced by fluids that form thick EHD films or reduce sliding friction. In order to determine if these same lubricant properties as well as other parameters, known to influence the fuel efficiency of axle lubricants, also affect contact fatigue damage in rolling contacts, an extensive experimental study using a rolling four ball test was performed. The tests were performed with a series of fluids that form thin and thick EHD films and have low and high sliding friction. Additionally, these fluids have been formulated to hav e high and low hydrodynamic friction. All these fluids contai ned additive packages that meet the API GL-5 gear oil specifications. The different properties of the lubricating fluids were controlled by changes to the base oils as well as addition of friction modifiers. The results have shown that it is possible do distinguish the pitting properties of the different lubricants by using rolling four ball tests. A multiple linear regression statistical analysis was performed with the use of Matlab for evaluating the results obtained from rolling four ball tests. The statistical model developed, showed that some of the physical properties of fluids that a ffect fuel efficiency have an impact on pitting performance of the lubricants. The ball test specimens from rolling four ball tests have been analyzed by using SEM/ EDS and XPS in order to characterize the tribochemical films and understand the damage mechanisms.
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