| 31. |
- Hansson, Marie, 1979, et al.
(författare)
-
Iodine content and distribution in extratumoral and tumor thyroid tissue analyzed with X-ray fluorescence and time-of-flight secondary ion mass spectrometry.
- 2008
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Ingår i: Thyroid : official journal of the American Thyroid Association. - : Mary Ann Liebert Inc. - 1557-9077. ; 18:11, s. 1215-20
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The thyroid's ability to enrich and store iodine has implications for thyroid cancer genesis, progression, and treatment. The study objective was to investigate thyroid iodine content (TIC) in tumoral and extratumoral tissue in patients with papillary thyroid cancer (PTC) as opposed to thyroid healthy controls using two different techniques: X-ray fluorescence (XRF) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). METHODS: Tissue samples from 10 patients with normal thyroids and 7 patients with PTC were collected. TIC was quantified with XRF, and the iodine stores were located on a histological level with TOF-SIMS. RESULTS: Mean TIC in controls was 0.6 mg/mL (range 0.3-1.2 mg/mL). For the cancer patients, the mean TIC was 0.8 mg/mL (range 0.2-2.3 mg/mL) in extratumoral thyroid tissue, but no iodine was detected in the tumors. TOF-SIMS investigation of the PTC patients showed significantly higher TIC in extratumoral tissue than in tumoral tissue. Iodine in the extratumoral tissue was predominantly located in the follicle lumen with a variation in concentration among follicles. CONCLUSIONS: XRF and TOF-SIMS are two complementary methods for obtaining insight into content and localization of iodine in the thyroid. XRF can be used in vitro or in vivo on a large number of samples or patients, respectively. TOF-SIMS on the other hand provides detailed images of the iodine location. The combined information from the two methods is of value for further studies on iodine metabolism in thyroid malignancy.
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| 32. |
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| 33. |
- Hellsten, Johan, et al.
(författare)
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Electroconvulsive seizures induce angiogenesis in adult rat hippocampus
- 2005
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Ingår i: Biological Psychiatry. - : Elsevier BV. - 0006-3223. ; 58:11, s. 871-878
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Tidskriftsartikel (refereegranskat)abstract
- Background: Electroconvulsive seizure (ECS)-treatment, a model for electroconvulsive therapy (ECT) has been shown to induce proliferation of endothelial cells in the dentate gyrus (DG) of adult rats. Here we quantified the net angiogenic response after hypoxia a known inducer of aniogenesis. Therefore we also examined the effect of oxygenation on ECS-induced proliferation of endothelial cells. Methods: Total endothelial cell numbers and vessel length were estimated utilizing design based stereological analysis methods. Endothelial cell proliferation in the DG after ECS with or withouy oxygenation was assessed using bromodeoxyuridine. Results: The total number of endothelial cell numbers and vessels lenght was increased. Oxygenation did not abolish the ECS-induced proliferation of endothelial cells in the DG. Conclusions: ECS-treatment induces a dramatic increase in endothelial cell proliferation leading to a 30% increase in the total numberof endothelial cells. The increase in cell number resulted i na 16% increase in vessel length. These findings raise the possibility that similar vascular growth is induced by clinically administered ECT.
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| 34. |
- Hogberg, Johan, et al.
(författare)
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Phthalate diesters and their metabolites in human breast milk, blood or serum, and urine as biomarkers of exposure in vulnerable populations
- 2008
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Ingår i: Journal of Environmental Health Perspectives. - : Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 116:3, s. 334-339
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Phthalates may pose a risk for perinatal developmental effects. An important question relates to the choice of suitable biological matrices for assessing exposure during this period. OBJECTIVES: This study was designed to measure the concentrations of phthalate diesters or their metabolites in breast milk, blood or serum, and urine and to evaluate their suitability for assessing perinatal exposure to phthalates. METHODS: In 2001, 2-3 weeks after delivery, 42 Swedish primipara provided breast milk, blood, and urine samples at home. Special care was taken to minimize contamination with phthalates (e.g., use of a special breast milk pump, heat treatment of glassware and needles, addition of phosphoric acid). RESULTS: Phthalate diesters and metabolites in milk and blood or serum, if detected, were present at concentrations close to the limit of detection. By contrast, most phthalate metabolites were detectable in urine at concentrations comparable to those from the general population in the United States and in Germany. No correlations existed between urine concentrations and those found in milk or blood/serum for single phthalate metabolites. Our data are at odds with a previous study documenting frequent detection and comparatively high concentrations of phthalate metabolites in Finnish and Danish mothers' milk. CONCLUSIONS: Concentrations of phthalate metabolites in urine are more informative than those in milk or serum. Furthermore, collection of milk or blood may be associated with discomfort and potential technical problems such as contamination (unless oxidative metabolites are measured). Although urine is a suitable matrix for health-related phthalate monitoring, urinary concentrations in nursing mothers cannot be used to estimate exposure to phthalates through milk ingestion by breast-fed infants.
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| 35. |
- Holmgren, Johan, 1977-, et al.
(författare)
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Public transport in towns : Inevitably on the decline?
- 2008
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Ingår i: Research in Transportation Economics. - : Elsevier BV. - 0739-8859 .- 1875-7979. ; 23:1, s. 65-74
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Tidskriftsartikel (refereegranskat)abstract
- In this article the post war development of public transport demand in the town of Linköping is explained using time series analysis. It is found that the dramatic increase in public transport demand between 1946 and 1983, at least in part, can be explained by the rapid increase in female labour force participation and the expansion of the city’s outer areas. After that, female labour force participation decreased slightly and the town expansion has stopped. Without these positive forces to counterbalance the rising levels of car ownership public transport demand has fallen by 71%. The effects of a policy change, including peak-load pricing, straighter bus routes, smaller bus size and staggered school hours, is analysed. It is found that the proposed package would increase public transport travel by 42 % compared to present policy.
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| 36. |
- Holmgren, Johan, 1977-
(författare)
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Studies in Local Public Transport Demand
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of four papers where the overall purpose is to contribute to the understanding of how local public transport demand is affected by different factors. An underlying theme running trough the thesis is the two-way relationship between public transport demand and the service level caused by the fact that capacity and quality are joint products.In Paper I the relationship between public transport demand and the service level (in terms of vehicle-kilometres) is investigated using panel data from Swedish counties. A Granger causality test is performed in order to test if the level of service cause public transport demand or if demand cause service level, or if they cause each other. It is found that demand and service cause each other, which is to say that there is a two-way relationship between them.In Paper II elasticity estimates for local public transport demand from previous research are summarised and the variation in results is analysed using meta-regression. The variation is explained by model specification, type of data used and origin of data.In Paper III a demand function for local public transport is estimated using panel data from Swedish counties. Instrument variable estimation is used in order to avoid the problem of a two-way relationship between demand and service level (vehicle-kilometres). Demand elasticities with respect to public transport fare, price of petrol, vehicle-kilometres and car ownership are found to be -0.4, 0.34, 0.55, and -1.37. After also taking the effects of income on car ownership into account, it is found that the total effect of income on public transport demand is close to zero.In Paper IV it is found that the strong increase in public transport demand in the town of Linköping between 1946 and 1983, in addition to fare, vehicle-kilometres and car ownership, can be explained by the rapid increase in female labour force participation and the expansion of the city’s outer areas. The city expansion is thought to have increased average trip distance and thereby reduced the number of trips that could be made walking or by bicycle. After 1983, female labour force participation decreased slightly and the expansion of the areas in question has stopped. Without these positive forces to counterbalance the rising levels of car ownership bus trips per capita has fallen by 71%. The effects of a policy change, including peak-load pricing, straighter bus routes, smaller bus size and staggered school hours, is analysed. It is found that the proposed changes would increase public transport travel by 42 % compared to present policy.
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| 37. |
- Ingvarsson, Johan, et al.
(författare)
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Design of recombinant antibody microarrays for serum protein profiling: Targeting of complement proteins
- 2007
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 6:9, s. 3527-3536
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Tidskriftsartikel (refereegranskat)abstract
- Antibody-based microarrays is a novel technology with great promise for high-throughput proteomics. The process of designing high-performing arrays has, however, turned out to be challenging. Here, we have designed the next generation of a human recombinant scFv antibody microarray platform for protein expression profiling of nonfractionated biotinylated human plasma and serum proteomes. The setup, based on black polymer Maxisorb slides interfaced with a fluorescent-based read-out system, was found to provide specific, sensitive (subpicomolar (pM) range) and reproducible means for protein profiling. Further, a chip-to-chip normalization protocol critical for comparing data generated on different chips was devised. Finally, the microarray data were found to correlate well with clinical laboratory data obtained using conventional methods, as demonstrated for a set of medium abundant (micromolar (mu M) to nanomolar (nM) range) protein analytes in serum and plasma samples derived from healthy and complement-deficient individuals.
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| 38. |
- Jansson, Gunnar, et al.
(författare)
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Vildsvinen och skogsbruket
- 2009
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Ingår i: Fakta. Skog. - 1400-7789.
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Annan publikation (populärvet., debatt m.m.)
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| 39. |
- Jansson, Johan, et al.
(författare)
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Algorithms and Data Structures for Multi-Adaptive Time-Stepping
- 2008
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Ingår i: ACM Transactions on Mathematical Software. - : Association for Computing Machinery (ACM). - 0098-3500 .- 1557-7295. ; 35:3
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Tidskriftsartikel (refereegranskat)abstract
- Multi-adaptive Galerkin methods are extensions of the standard continuous and discontinuous Galerkin methods for the numerical solution of initial value problems for ordinary or partial differential equations. In particular, the multi-adaptive methods allow individual and adaptive time steps to be used for different components or in different regions of space. We present algorithms for efficient multi-adaptive time-stepping, including the recursive construction of time slabs and adaptive time step selection. We also present data structures for efficient storage and interpolation of the multi-adaptive solution. The efficiency of the proposed algorithms and data structures is demonstrated for a series of benchmark problems.
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| 40. |
- Jansson, Johan, 1978
(författare)
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Automated Computational Modeling
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is part of the FEniCS project of Automation of Computational Mathematical Modeling (ACMM) as the modern manifestation of the basic principle of science:formulating mathematical equations (modeling) and solving equations (computation). The vision of FEniCS is to set a new standard towards the goals of generality, efficiency, and simplicity, concerning mathematical methodology, implementation, and application.ACMM includes the key steps of Automation of (a) discretization of differential equations,(b) solution of discrete systems, (c) error control of discrete solutions, (d) optimizationand (e) modeling. FEniCS is based on adaptive finite element methods (FEM) [1]. This thesis presents the following examples of Automated Computational Modeling asconcrete realizations of ACMM with main focus on (a)-(c): MG: Multi-adaptive Galerkin ODE-solver: This part concerns the automation of (a1) discretization in time by the MG implementation of the multi-adaptive ODE-solver mcG(q)/mdG(q) formulated in the thesis ([9]) by Anders Logg, based on Galerkin's method with continuous/discontinuous piecewise polynomial approximation in time of degree q with different time steps for different components, automati- cally determined by a posteriori error estimation. MG realizes automation of (a1) by Galerkin's method, (b) by fixed-point or Newton's method, and (c) by a posteriori error estimation using duality. MG is the first general multi-adaptive ODE-solver with automatic error control based on duality. MG has potentially a very vast range of applicability. MG may also be run in mono-adaptive form with the same time step for all components, eliminating the over-head required for multi-adaptivity. For bench-mark problems with different time scales, we demonstrate substantial performance gains with MG, as compared to mono-adaptive solvers. MG is joint work with Anders Logg. Ko: Solid mechanics solver: This part includes the automation of (a2) discretization in space of a general continuum model for solid mechanics with elasto-visco-plastic materials and large displacements, rotations and deformations. When coupled with MG for time-discretization this gives the solid mechanics solver Ko realizing (a) and (b) with (c) in progress. Ko is based on an updated Lagrangian formulation where equilibrium and constitutive equations are expressed on the current deformed configuration. Ko is the first automated solid mechanics solver and the range of possible applications is very large. We show that the performance of Ko is comparable to that of a mass-spring solver, which is the industry standard for performance-intensive solid mechanics simulations [8]. Ko demonstrates the general capability and potential of FEniCS. DOLFIN as a PSE: We present the FEniCS tool chain, and in particular DOLFIN, as a general and automated problem solving environment (PSE). DOLFIN realizes the overall concept of automated computational modeling by taking a PDE in mathematical notation as input and automatically discretizing and computing the solution by the FEM with full efficiency, including automated time discretization of time dependent PDE with the ODE solver. This is joint work with Johan Hoffman, Anders Logg and Garth Wells. Automated Modeling: We present a case study of automated modeling (e) in a model problem with a fast and a slow time scale. By resolving the fast time scale for a short period of time an effective coefficient is determined by optimization, which allows simulation of the slow time scale over long time. This is joint work with Claes Johnson and Anders Logg.
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