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| 4. |
- Abbatt, J. P. D., et al.
(författare)
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Halogen activation via interactions with environmental ice and snow in the polar lower troposphere and other regions
- 2012
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 12:14, s. 6237-6271
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Tidskriftsartikel (refereegranskat)abstract
- The role of ice in the formation of chemically active halogens in the environment requires a full understanding because of its role in atmospheric chemistry, including controlling the regional atmospheric oxidizing capacity in specific situations. In particular, ice and snow are important for facilitating multiphase oxidative chemistry and as media upon which marine algae live. This paper reviews the nature of environmental ice substrates that participate in halogen chemistry, describes the reactions that occur on such substrates, presents the field evidence for ice-mediated halogen activation, summarizes our best understanding of ice-halogen activation mechanisms, and describes the current state of modeling these processes at different scales. Given the rapid pace of developments in the field, this paper largely addresses advances made in the past five years, with emphasis given to the polar boundary layer. The integrative nature of this field is highlighted in the presentation of work from the molecular to the regional scale, with a focus on understanding fundamental processes. This is essential for developing realistic parameterizations and descriptions of these processes for inclusion in larger scale models that are used to determine their regional and global impacts.
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| 5. |
- Abrahamsson, Christian, et al.
(författare)
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Review section vision
- 2008
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Ingår i: Environment and Planning D: Society and Space. ; 26:2, s. 192-194
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Abrahamsson, Dimitri, et al.
(författare)
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In Silico Structure Predictions for Non-targeted Analysis : From Physicochemical Properties to Molecular Structures
- 2022
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Ingår i: Journal of the American Society for Mass Spectrometry. - : American Chemical Society (ACS). - 1044-0305 .- 1879-1123. ; 33:7, s. 1134-1147
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Tidskriftsartikel (refereegranskat)abstract
- While important advances have been made in high-resolution mass spectrometry (HRMS) and its applications in non-targeted analysis (NTA), the number of identified compounds in biological and environmental samples often does not exceed 5% of the detected chemical features. Our aim was to develop a computational pipeline that leverages data from HRMS but also incorporates physicochemical properties (equilibrium partition ratios between organic solvents and water; Ksolvent–water) and can propose molecular structures for detected chemical features. As these physicochemical properties are often sufficiently different across isomers, when put together, they can form a unique profile for each isomer, which we describe as the “physicochemical fingerprint”. In our study, we used a comprehensive database of compounds that have been previously reported in human blood and collected their Ksolvent–water values for 129 partitioning systems. We used RDKit to calculate the number of RDKit fragments and the number of RDKit bits per molecule. We then developed and trained an artificial neural network, which used as an input the physicochemical fingerprint of a chemical feature and predicted the number and types of RDKit fragments and RDKit bits present in that structure. These were then used to search the database and propose chemical structures. The average success rate of predicting the right chemical structure ranged from 60 to 86% for the training set and from 48 to 81% for the testing set. These observations suggest that physicochemical fingerprints can assist in the identification of compounds with NTA and substantially improve the number of identified compounds.
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| 7. |
- Abrahamsson, Gun, 1961-, et al.
(författare)
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Problemlösningsarbete på låg organisatorisk nivå : Två studier om implementering respektive konkretisering av idéer om kundorderstyrd tillverkning
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The two studies reported in this thesis are about problem solving at a low organisational level in an organisational unit in a Swedish manufacturing company, which has adopted ideas of World Class Manufacturing. In the first study, we analyse, from an organisational learning perspective, the implementation of the well-known concept Continuous Improvement at shop-floor level and how management accounting may facilitate or impede improvement work. A case study was conducted in two workgroups in one production unit for about seven months. In one of the groups, management accounting facilitated improvement work with high organisational scope and, in the other group, impeded the organisational scope. Our conclusion is that management accounting may facilitate a high organisational scope by supporting the leadership style, stressing co-operation, dialog and participation, or, by the way the manager uses management accounting, make boundaries distinct between groups of employees and between departments, and therefore impede improvements with high organisational scope. In the second study, we analyse, from a rule-based behavioural perspective, how ideas of World Class Manufacturing are institutionalised in cross-functional problem solving at a low organisational level. A case study was carried out in two cross-functional weekly group meetings for about nine months. Problems raised and solutions decided followed a repeated pattern. The actors draw on instrumental rules, which can be described as technical as well as economic. We concluded that ideas of World Class Manufacturing were institutionalised as different variants of World Class Manufacturing in the different functions at a low organisational level. At the meetings, contradictory instrumental rules were activated by the functions and treated according to interaction rules. Two overall patterns of action, articulated the two main interaction rules guiding actors in how to treat contradictory ideas of World Class Manufacturing.
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| 8. |
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| 9. |
- Abrahamsson, Oskar, 1986, et al.
(författare)
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Candle: A Verified Implementation of HOL Light
- 2022
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Ingår i: Leibniz International Proceedings in Informatics, LIPIcs. - 1868-8969. ; 237
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Konferensbidrag (refereegranskat)abstract
- This paper presents a fully verified interactive theorem prover for higher-order logic, more specifically: a fully verified clone of HOL Light. Our verification proof of this new system results in an end-to-end correctness theorem that guarantees the soundness of the entire system down to the machine code that executes at runtime. Our theorem states that every exported fact produced by this machine-code program is valid in higher-order logic. Our implementation consists of a read-eval-print loop (REPL) that executes the CakeML compiler internally. Throughout this work, we have strived to make the REPL of the new system provide a user experience as close to HOL Light's as possible. To this end, we have, e.g., made the new system parse the same variant of OCaml syntax as HOL Light. All of the work described in this paper has been carried out in the HOL4 theorem prover.
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| 10. |
- Abrahamsson, Per-Anders, et al.
(författare)
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Radioimmunoassay of beta-microseminoprotein, a prostatic-secreted protein present in sera of both men and women
- 1989
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Ingår i: Clinical Chemistry. - 0009-9147. ; 35:7, s. 1497-1503
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Tidskriftsartikel (refereegranskat)abstract
- We describe a simple radioimmunoassay of beta-microseminoprotein, one of the three most abundant secretory proteins of the prostate gland. The detection limit of the assay is 1 microgram/L, and its precision, expressed as the total coefficient of variation, is less than 10% for values between 10 and 150 micrograms/L. Using this assay, we found that beta-microseminoprotein immunoreactivity was present in sera from both sexes at about the same concentration. The protein detected had the same molecular size on gel chromatography as the protein isolated from seminal plasma, and dilution curves for the sera paralleled that for the pure protein. The findings suggest that beta-microseminoprotein is present in serum of healthy subjects of both sexes and that it originates in tissue other than the prostate gland. The range of the serum concentration was 0-10.6 micrograms/L (median 4.1) for 51 healthy adult women and 1.1-14.7 micrograms/L (median 6.2) for 35 healthy adult men not older than 40 years. In males with prostatic cancer the concentration in serum was highly variable and often greatly increased. The concentration of beta-microseminoprotein was correlated with that of creatinine in serum, suggesting that the protein is eliminated--at least partly--from the circulation by glomerular filtration. Little of the protein was present in the urine of women. In urine from men the concentration was high and variable, probably because of local contribution from the prostate gland to the urethral urine.
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| 11. |
- Abrahamsson, Thomas, et al.
(författare)
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A Th1/Th2-associated chemokine imbalance during infancy in children developing eczema, wheeze and sensitization
- 2011
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Ingår i: Clinical and Experimental Allergy. - : Blackwell Publishing. - 0954-7894 .- 1365-2222. ; 41:12, s. 1729-1739
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Tidskriftsartikel (refereegranskat)abstract
- Background Analyses of circulating chemokines offer novel tools to investigate the T helper (Th)1/Th2 imbalance in allergic disease in vivo. less thanbrgreater than less thanbrgreater thanObjective To relate circulating Th1- and Th2-associated chemokines in infancy to allergic disease, sensitization and probiotic supplementation. less thanbrgreater than less thanbrgreater thanMethods Circulating levels of Th1-associated CXC-chemokine ligand (CXCL) 9, CXCL10 and CXCL11 and Th2-associated CC-chemokine ligand (CCL)17 and CCL22 were assessed with Luminex and CCL18 with enzyme-linked immunosorbent assay at birth (n = 109), 6 (n = 104), 12 (n = 116) and 24 months (n = 123) in 161 infants completing a double-blind placebo-controlled allergy prevention trial with Lactobacillus reuteri during the last month of gestation and through the first year of life. The infants were followed regarding the development of allergic disease and sensitization until 2 years of age. less thanbrgreater than less thanbrgreater thanResults The Th2-associated chemokines CCL17 and CCL22 were the highest at birth and then decreased, whereas CCL18 and the Th1-associated chemokines increased with age. High Th2-associated chemokine levels were observed in children developing allergic disease. Sensitization was preceded by elevated levels of the Th2-associated CCL22 and reduced levels of the Th1-associated CXCL11 already at birth. The Th2-associated CCL17 was also elevated at birth in infants developing recurrent wheeze. A high Th2/Th1 ratio (CCL22/CXCL10) at birth associated with both sensitization and eczema development. The presence of L. reuteri in stool in the first week of life was associated with low CCL17 and CCL22 and high CXCL11 levels at 6 months of age. High Th1-associated chemokine levels were associated with day-care. less thanbrgreater than less thanbrgreater thanConclusion and Clinical Relevance Allergic disease and sensitization in infancy was associated with low circulating Th1- and high Th2-associated chemokine levels already from birth. Circulating chemokines are useful for investigating the Th1/Th2 imbalance in allergic disease in vivo. Elucidation of the role of chemokines in allergic diseases may lead to future treatments.
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| 12. |
- Abrahamsson, Thomas, et al.
(författare)
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A Th1/Th2-associated chemokine imbalance preceding allergic disease is influenced by birth size, breastfeeding, daycare and probiotics
- 2009
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Ingår i: in Allergy, vol 64. ; , s. 56-56
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Konferensbidrag (refereegranskat)abstract
- Background: Analyses of circulating chemokines offer novel tools to investigate the Th1/Th2 imbalance in allergic disease in vivo and explore the influence of pre- and postnatal factors in infancy. Objective: To relate circulating Th1- and Th2-associated chemokines to the development of allergic disease, pre- and postnatal factors and probiotic supplementation in infancy. Methods: Circulating levels of Th1-associated CXC-chemokine ligand (CXCL)9, CXCL10 and CXCL11 and Th2-associated CC-chemokine ligand (CCL)17, CCL18 and CCL22 were assessed with Luminex and ELISA at birth (n=109), 6 (n=104), 12 (n=116) and 24 months (n=123) in 179 infants completing a double-blind placebo-controlled allergy prevention trial with Lactobacillus reuteri during the last month of gestation and through the first year of life. The infants were followed regarding development of allergic disease and sensitization until two years of age. Results: The Th2-associated chemokines were as highest at birth and then decreased, whereas the Th1-associated chemokines increased with age. Low Th1- and high Th2-associated chemokine levels were observed in children developing allergic disease. Sensitization was preceded by elevated CCL22 and reduced CXCL11 levels. High Th2-associated chemokine46 levels were associated with increased birth length and weight and long duration of breastfeeding, and high Th1-associated chemokine levels with day-care attendance. Presence of L. reuteri in stool the first week of life was associated with low CCL17 and CCL22 and high CXCL11 levels at 6 months. Conclusion: Allergic disease in infancy was associated with low circulating Th1- and high Th2-associated chemokine levels during the first year of life. The chemokine levels were affected by both pre and –postnatal factors.
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| 13. |
- Abrahamsson, Thomas, 1956, et al.
(författare)
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Calibration and cross-validation of a car component using frequency response functions and a damping equalization technique
- 2014
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Ingår i: 26th International Conference on Noise and Vibration Engineering, ISMA 2014, Including the 5th International Conference on Uncertainty in Structural Dynamics, USD 2014. - 9789073802919 ; , s. 2625-2640
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Konferensbidrag (refereegranskat)abstract
- The calibration of an FE model of a car subframe is reported. In this calibration the minimum deviation between finite element model data and experimental data is searched for. The outcome of the calibrated model and cross-validation results are compared with results of testing being made on an ensemble of seemingly identical subframes. The subframe model has 250,440 degrees-of-freedom and the calibration is made for 16 uncertain model parameters. The efficiency of the calibration procedure under these conditions is reported. With model calibration being a cornerstone of the finite element validation procedure, the calibration problem is normally characterized as being a large scale optimization problem with many model parameters to solve for and with deviation metric that are nonlinear in these parameters. The calibrated parameters need to be found by iterative procedures, starting from initial estimates of parameter values. Sometimes these procedures get trapped in local deviation function minima and do not converge to the globally optimal calibration solution that is searched for. Here, a calibration formulation which gives a smooth deviation metric with a large radius of convergence to the global minimum is used. A method that utilizes damping equalization is used to avoid the mode correlation and mode pairing problem that need to be solved in various other model updating procedures. The method is combined with model reduction for increased speed and employs the Levenberg-Marquardt minimizer with randomized starts to achieve the calibration solution. The MATLAB-based open-domain software tool FEMcali has been used for calibration, validation and cross-validation.
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| 14. |
- Abrahamsson, Thomas, 1956, et al.
(författare)
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Calibration and Validation of a Car Subframe Finite Element Model Using Frequency Responses
- 2015
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Ingår i: Conference Proceedings of the Society for Experimental Mechanics Series. - Cham : Springer International Publishing. - 2191-5644 .- 2191-5652. - 9783319152516 ; 10, s. 9-22
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Konferensbidrag (refereegranskat)abstract
- A finite element model of a car front subframe has been calibrated against test data. Stepped-sine testing has been used to give frequency response function estimates on an ensemble of seemingly identical subframes. Therefore, the deviation between test data and simulation results can be compared in a meaningful way by the outcome of model calibration and cross-validation. Emphasis has been put on the preparation of the test pieces for high fidelity testing and on bettering the chances of getting a calibration outcome that provides insight into the physical processes that govern the subframe dynamics. The front subframe model has more than 200,000 degrees-of-freedom and 17 model calibration parameters. The efficiency of the calibration procedure under these conditions is reported. To achieve efficiency, a calibration with a smooth deviation metric is used together with a damping equalization method that eliminates the need for matching of experimental and analytical eigenmodes. The method is combined with surrogate model frequency response evaluation based on model reduction for increased speed. The Matlab based open-domain software tool FEMcali that employs the Levenberg-Marquardt minimizer with randomized starts has been used for calibration and an unregularized Gauss-Newton minimizer has been used in the cross-validation.
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| 15. |
- Abrahamsson, Thomas, 1968-
(författare)
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Can Lactobacillus Reuteri Prevent Allergic Disease in Early Childhood?
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: An altered microbial exposure may be partly responsible for the increase of allergic diseases in populations with a western lifestyle. Activation of the immune system by microbes early in life is probably required for an accurate maturation of the immune system. Probiotics, live bacteria which are considered to confer health when ingested, have been suggested to prevent eczema and sensitisation infants.Aim: The general aim of this thesis was to assess the effect of oral supplementation with the probiotic bacterium Lactobacillus reuteri (L. reuteri) in infancy on the development of allergic disease and sensitisation during the first 2 years of life and to examine mechanisms possibly underlying eventual effects on allergic manifestations.Subjects: The thesis is based on results obtained from a prospective double-blind placebo-controlled multicenter trial, comprising 232 families with allergic disease, of whom 188 completed the study.Methods: The families were recruited at the antenatal clinic, and the mothers received L. reuteri ATCC 55730 (1 x 108 colony forming units) or placebo daily from gestational week 36 until delivery. Their babies then continued with the same study product from birth until 12 months of age and were followed up for another year. The primary outcomes were allergic disease, with or without positive skin prick test or circulating IgE to food allergens. Bacterial counts and prevalence were assessed in maternal breast milk and faeces and infant faeces, employing conventional cultivation methods. Cytokines and IgA antibodies were analysed in colostrum and mature milk from the mothers with ELISA, and Na/K- ratio in breast milk with ion selective electrodes. Circulating Th1/Th2-associated chemokines were analysed in cord and peripheral blood in the infants with Luminex or ELISA technique.Results: The incidence of eczema was similar, 36% in the treated versus 34% in the placebo group. The L. reuteri group had a lower cumulative incidence of IgE-associated allergic disease, 20% versus 35% (p=0.04), and less IgE-associated eczema during the second year, 8% versus 20% (p=0.02). The prevalence of L. reuteri was higher during the first year of life in stool samples from infants, as well as in colostrum, in the active as compared to the placebo treated group. Colostrum from L. reuteri supplemented mothers had lower levels of TGF-β2, and low levels of this cytokine were associated with less sensitisation. Low Th1- and high Th2-associated chemokine levels preceded allergic disease. The presence of L. reuteri in stool was associated with lower levels of the Th2-associated chemokines CCL17 and CCL22 and higher levels of the Th1-associated CXCL11.Conclusion: Although a preventive effect of probiotics on infant eczema was not confirmed, the L. reuteri treated infants had lower incidence of IgE-associated allergic disease at two years of age, and therefore possibly run a reduced risk to develop later respiratory allergic disease. The mechanisms underlying this effect require further elucidation.
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| 18. |
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| 19. |
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| 20. |
- Abrahamsson, Thomas, 1956, et al.
(författare)
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FEM calibration with FRF damping equalization
- 2014
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Ingår i: Conference Proceedings of the Society for Experimental Mechanics Series. - Cham : Springer International Publishing. - 2191-5644 .- 2191-5652. - 9783319007670 ; 3, s. 265-278
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Konferensbidrag (refereegranskat)abstract
- A finite element model calibration procedure that uses frequency response function data and relies on damping equalization is presented. In this, the dampings of the finite element model and the corresponding experimental model are set equal before calibration. The damping equalization is made to avoid the mode pairing problem that normally needs to be solved in other model updating procedures. It is demonstrated that one particular use of frequency response data gives a calibration deviation metric that is smooth in the variation of model parameters and give a large radius of convergence to the calibration minimum. The method is combined with model reduction for increased speed and employs a minimizing procedure that employs randomized multiple starting points in the parameter space to get to the calibration solution. The performance of the calibration procedure is demonstrated by two numerical examples. © The Society for Experimental Mechanics, Inc. 2014.
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| 21. |
- Abrahamsson, Thomas, 1956, et al.
(författare)
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Finite element model calibration using frequency responses with damping equalization
- 2015
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Ingår i: Mechanical Systems and Signal Processing. - : Elsevier BV. - 0888-3270 .- 1096-1216. ; 62-63, s. 218-234
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Tidskriftsartikel (refereegranskat)abstract
- Model calibration is a cornerstone of the finite element verification and validation procedure, in which the credibility of the model is substantiated by positive comparison with test data. The calibration problem, in which the minimum deviation between finite element model data and experimental data is searched for, is normally characterized as being a large scale optimization problem with many model parameters to solve for and with deviation metrics that are nonlinear in these parameters. The calibrated parameters need to be found by iterative procedures, starting from initial estimates. Sometimes these procedures get trapped in local deviation function minima and do not converge to the globally optimal calibration solution that is searched for. The reason for such traps is often the multi-modality of the problem which causes eigenmode crossover problems in the iterative variation of parameter settings. This work presents a calibration formulation which gives a smooth deviation metric with a large radius of convergence to the global minimum. A damping equalization method is suggested to avoid the mode correlation and mode pairing problems that need to be solved in many other model updating procedures. By this method, the modal damping of a test data model and the finite element model is set to be the same fraction of critical modal damping. Mode pairing for mapping of experimentally found damping to the finite element model is thus not needed. The method is combined with model reduction for efficiency and employs the Levenberg-Marquardt minimizer with randomized starts to achieve the calibration solution. The performance of the calibration procedure, including a study of parameter bias and variance under noisy data conditions, is demonstrated by two numerical examples.
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| 22. |
- Abrahamsson, Thomas, et al.
(författare)
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Gut microbiota and allergy: the importance of the pregnancy period
- 2015
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Ingår i: Pediatric Research. - : Nature Publishing Group: Open Access Hybrid Model Option A. - 0031-3998 .- 1530-0447. ; 77:1, s. 214-219
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Forskningsöversikt (refereegranskat)abstract
- Limited microbial exposure is suggested to underlie the increase of allergic diseases in affluent countries, and bacterial diversity seems to be more important than specific bacteria taxa. Prospective studies indicate that the gut microbiota composition during the first months of life influences allergy development, and support the theory that factors influencing the early maturation of the immune system might be important for subsequent allergic disease. However, recent research indicates that microbial exposure during pregnancy may be even more important for the preventative effects against allergic disease. This review gives a background of the epidemiology, immunology, and microbiology literature in this field. It focuses on possible underlying mechanisms such as immune-regulated epigenetic imprinting and bacterial translocation during pregnancy, potentially providing the offspring with a pioneer microbiome. We suggest that a possible reason for the initial exposure of bacterial molecular patterns to the fetus in utero is to prime the immune system and/or the epithelium to respond appropriately to pathogens and commensals after birth.
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| 23. |
- Abrahamsson, Thomas, et al.
(författare)
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Low diversity of the gut microbiota in infants with atopic eczema
- 2012
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Ingår i: Journal of Allergy and Clinical Immunology. - New York, USA : Elsevier BV. - 0091-6749 .- 1097-6825. ; 129:2, s. 434-U244
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: It is debated whether a low total diversity of the gut microbiota in early childhood is more important than an altered prevalence of particular bacterial species for the increasing incidence of allergic disease. The advent of powerful, cultivation-free molecular methods makes it possible to characterize the total microbiome down to the genus level in large cohorts. OBJECTIVE: We sought to assess microbial diversity and characterize the dominant bacteria in stool during the first year of life in relation to atopic eczema development. METHODS: Microbial diversity and composition were analyzed with barcoded 16S rDNA 454-pyrosequencing in stool samples at 1 week, 1 month, and 12 months of age in 20 infants with IgE-associated eczema and 20 infants without any allergic manifestation until 2 years of age (ClinicalTrials.gov ID NCT01285830). RESULTS: Infants with IgE-associated eczema had a lower diversity of the total microbiota at 1 month (P= .004) and a lower diversity of the bacterial phylum Bacteroidetes and the genus Bacteroides at 1 month (P= .02 and P= .01) and the phylum Proteobacteria at 12 months of age (P= .02). The microbiota was less uniform at 1 month than at 12 months of age, with a high interindividual variability. At 12 months, when the microbiota had stabilized, Proteobacteria, comprising gram-negative organisms, were more abundant in infants without allergic manifestation (Empirical Analysis of Digital Gene Expression in R edgeR test: P= .008, q= 0.02). CONCLUSION: Low intestinal microbial diversity during the first month of life was associated with subsequent atopic eczema.
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| 24. |
- Abrahamsson, Thomas, et al.
(författare)
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Low gut microbiota diversity in early infancy precedes asthma at school age
- 2014
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Ingår i: Clinical and Experimental Allergy. - : Wiley. - 0954-7894 .- 1365-2222. ; 44:6, s. 842-850
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Tidskriftsartikel (refereegranskat)abstract
- Background Low total diversity of the gut microbiota during the first year of life is associated with allergic diseases in infancy, but little is known how early microbial diversity is related to allergic disease later in school age. Objective To assess microbial diversity and characterize the dominant bacteria in stool during the first year of life in relation to the prevalence of different allergic diseases in school age, such as asthma, allergic rhinoconjunctivitis (ARC) and eczema. Methods The microbial diversity and composition was analysed with barcoded 16S rDNA 454 pyrosequencing in stool samples at 1week, 1month and 12months of age in 47 infants which were subsequently assessed for allergic disease and skin prick test reactivity at 7years of age (ClinicalTrials.gov ID NCT01285830). Results Children developing asthma (n=8) had a lower diversity of the total microbiota than non-asthmatic children at 1week (P=0.04) and 1month (P=0.003) of age, whereas allergic rhinoconjunctivitis (n=13), eczema (n=12) and positive skin prick reactivity (n=14) at 7years of age did not associate with the gut microbiota diversity. Neither was asthma associated with the microbiota composition later in infancy (at 12months). Children having IgE-associated eczema in infancy and subsequently developing asthma had lower microbial diversity than those that did not. There were no significant differences, however, in relative abundance of bacterial phyla and genera between children with or without allergic disease. Conclusion and Clinical Relevance Low total diversity of the gut microbiota during the first month of life was associated with asthma but not ARC in children at 7years of age. Measures affecting microbial colonization of the infant during the first month of life may impact asthma development in childhood.
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| 25. |
- Abrahamsson, Thomas, et al.
(författare)
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Microbiota in Functional Gastrointestinal Disorders in Infancy: Implications for Management
- 2017
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Ingår i: INTESTINAL MICROBIOME: FUNCTIONAL ASPECTS IN HEALTH AND DISEASE. - : KARGER. - 9783318060317 - 9783318060300 ; , s. 107-115
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Konferensbidrag (refereegranskat)abstract
- The complex and diverse intestinal microbiome is recognized as important in promoting human health. An altered gut microflora, referred to as dysbiosis, is increasingly recognized as having an etiologic role in a variety of conditions, including functional gastrointestinal disorders: colic in infants and irritable bowel syndrome in older children. Probiotics are defined as live microorganisms that, if ingested in sufficient amounts, restore microbial homeostasis and have a benefit on health. Randomized controlled trials indicate that probiotics can be effective in a variety of intestinal conditions, including colic and irritable bowel syndrome. Probiotics may promote gut microbial diversity, but timing of the intervention appears crucial. Strain-specific effects on colonization resistance, epithelial barrier integrity, modulation of signal transduction, impacts on innate and adaptive immune responses, and effects on visceral hyperalgesia likely explain the observed variability in various probiotic strains. In the future, probiotics are likely to be chosen for use in a defined clinical setting based on underlying mechanism(s) of action. The precise component of the probiotic agent mediating observed effects is the subject of current research. Unresolved issues relate to optimal dosages, timing of ingestion, single versus combination formulations, maintenance of viability in storage, and the merits of employing probiotic- derived products. (C) 2017 Nestec Ltd., Vevey/S. Karger AG, Basel
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