| 1. |
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| 2. |
- Ericsson, Anette, 1975, et al.
(författare)
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Hormonal regulation of glucose and system A amino acid transport in first trimester placental villous fragments.
- 2005
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Ingår i: American journal of physiology. Regulatory, integrative and comparative physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 288:3
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Tidskriftsartikel (refereegranskat)abstract
- Alterations in placental nutrient transfer have been implicated in fetal growth abnormalities. In pregnancies complicated by diabetes and accelerated fetal growth, upregulations of glucose transporter 1 (GLUT1) and amino acid transporter system A have been shown in the syncytiotrophoblast of term placenta. In contrast, intrauterine growth restriction is associated with a downregulation of placental system A transporters. However, underlying mechanisms of transporter regulation are poorly understood, particularly in early pregnancy. In this study, hormonal regulation of placental glucose and system A transporters was investigated. The uptake of 3-O-[methyl-(14)C]-d-glucose was studied in villous fragments isolated from first trimester (6-13 wk of gestation) and term human placenta. Villous fragments were incubated in buffer containing insulin, leptin, cortisol, growth hormone (GH), prolactin, IGF-I, or under hypo/hyperglycemic conditions for 1 h. Subsequently, 3-O-[methyl-(14)C]-D-glucose uptake was measured with and without phloretin for 70 s in first trimester tissue and 20 s in term tissue. Methylaminoisobutyric uptake was measured with and without Na+ for 20 min. Glucose uptake was unaltered by hormones or hypo/hyperglycemia. GH decreased system A activity by 31% in first trimester (P < 0.05). The uptake of glucose was 50% higher in term compared with first trimester fragments and increased markedly between 6 and 13 wk of gestation (P < 0.05). We conclude that placental glucose transporter activity is not regulated by short exposures to the hormones or glucose concentrations tested. In contrast to term placental villous fragments, system A activity was not regulated by insulin or leptin in first trimester but was downregulated by GH.
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| 3. |
- Jansson, Nina, 1976, et al.
(författare)
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Down-regulation of placental transport of amino acids precedes the development of intrauterine growth restriction in rats fed a low protein diet.
- 2006
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Ingår i: The Journal of physiology. - : Wiley. - 0022-3751. ; 576:Pt 3, s. 935-46
-
Tidskriftsartikel (refereegranskat)abstract
- Intrauterine growth restriction (IUGR) represents an important risk factor for perinatal complications and for adult disease. IUGR is associated with a down-regulation of placental amino acid transporters; however, whether these changes are primary events directly contributing to IUGR or a secondary consequence is unknown. We investigated the time course of changes in placental and fetal growth, placental nutrient transport in vivo and the expression of placental nutrient transporters in pregnant rats subjected to protein malnutrition, a model for IUGR. Pregnant rats were given either a low protein (LP) diet (n = 64) or an isocaloric control diet (n = 66) throughout pregnancy. Maternal insulin, leptin and IGF-I levels decreased, whereas maternal amino acid concentrations increased moderately in response to the LP diet. Fetal and placental weights in the LP group were unaltered compared to control diet at gestational day (GD) 15, 18 and 19 but significantly reduced at GD 21. Placental system A transport activity was reduced at GD 19 and 21 in response to a low protein diet. Placental protein expression of SNAT2 was decreased at GD 21. In conclusion, placental amino acid transport is down-regulated prior to the development of IUGR, suggesting that these placental transport changes are a cause, rather than a consequence, of IUGR. Reduced maternal levels of insulin, leptin and IGF-1 may link maternal protein malnutrition to reduced fetal growth by down-regulation of key placental amino acid transporters.
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| 4. |
- Turcot, Valerie, et al.
(författare)
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Protein-altering variants associated with body mass index implicate pathways that control energy intake and expenditure in obesity
- 2018
-
Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 50:1, s. 26-41
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have identified >250 loci for body mass index (BMI), implicating pathways related to neuronal biology. Most GWAS loci represent clusters of common, noncoding variants from which pinpointing causal genes remains challenging. Here we combined data from 718,734 individuals to discover rare and low-frequency (minor allele frequency (MAF) < 5%) coding variants associated with BMI. We identified 14 coding variants in 13 genes, of which 8 variants were in genes (ZBTB7B, ACHE, RAPGEF3, RAB21, ZFHX3, ENTPD6, ZFR2 and ZNF169) newly implicated in human obesity, 2 variants were in genes (MC4R and KSR2) previously observed to be mutated in extreme obesity and 2 variants were in GIPR. The effect sizes of rare variants are similar to 10 times larger than those of common variants, with the largest effect observed in carriers of an MC4R mutation introducing a stop codon (p.Tyr35Ter, MAF = 0.01%), who weighed similar to 7 kg more than non-carriers. Pathway analyses based on the variants associated with BMI confirm enrichment of neuronal genes and provide new evidence for adipocyte and energy expenditure biology, widening the potential of genetically supported therapeutic targets in obesity.
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| 5. |
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| 6. |
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| 7. |
- Fall, David, 1983, et al.
(författare)
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Modelling cracking and bending failure of SFRC beams with conventional reinforcement
- 2013
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Ingår i: 8th International Conference on Fracture Mechanics of Concrete and Concrete Structures. - 9788494100413 ; , s. 1276-1285
-
Konferensbidrag (refereegranskat)abstract
- In this study three beams, with varying contents of steel fibre reinforcement, were tested in four point bending and compared with results from FE-analysis. The beams were part of a larger experimental programme where relevant material properties were investigated. FE-modelling was performed using a two dimensional model. Concrete was represented by four-node quadrilateral isoperimetric plane stress elements. The smeared crack approach was utilized and the stress-strain relation describing the tensile behavior of the concrete was calculated from uni-axial test results, assuming the crack bandwidth to be equal to the element length. In compression, the concrete was assumed to behave elasto ideal-plastic. The reinforcement was modelled by straight 2-node truss elements connected to the concrete by two-dimensional interface elements providing the bond-slip properties. A material model including hardening effects was derived from tension tests of reinforcement bars and used for modelling the conventional reinforcement. A multi-linear bond-slip model was established through pull-out tests. As an alternative, analyses were also performed taking into account a reduction of the bond stress after yielding of the reinforcement occurred. Loading was applied in two phases: the first comprehending only the self-weight, while incremental loading was applied by deformation control during the second phase. General agreement between experiments and FE-analyses was obtained with regard to load-displacement behaviour. By observing the crack patterns, both from FE-analysis and experiments, it can be concluded that the general behaviour agreed; however, in the analyses not all cracks were fully localized. A higher degree of crack localization was obtained when the bond loss at yielding was included.
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| 8. |
- Fall, David, 1983, et al.
(författare)
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Non-linear Finite Element Analysis of Steel Fibre Reinforced Beams with Conventional Reinforcement
- 2012
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Ingår i: 8th RILEM International Symposium on Fiber Reinforced Concrete: challenges and opportunities (BEFIB 2012). - 9782351581322 ; , s. 1033-1045
-
Konferensbidrag (refereegranskat)abstract
- The purpose of this study has been to investigate the behavior of elements reinforced with both conventional steel reinforcement and steel fibres in order to support future applications of such composites. Three beams of varying fibre content were tested in four-point bending. The results were then compared with results from nonlinear FE-analyses and the calculation method suggested in fib Model Code 2010. The beams were a part of a larger experimental programme where relevant properties were investigated in uniaxial tension tests and pull-out tests. The FE-modeling was performed using a two dimensional plane stress model. General agreement between experiments and the FE-analyses was obtained with regard to load-displacement behavior. The crack patterns from the FE-analysis and experiments agreed in general, although the crack patterns in the analysis were more distributed close to the reinforcement. Crack localization was enhanced by modifying the bond-slip behavior to include the bond loss at yielding. Calculations in accordance with fib Model Code 2010 yield conservative results in comparison with both experiments and FE-analysis.
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| 9. |
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| 10. |
- Heid, Iris M, et al.
(författare)
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Meta-analysis identifies 13 new loci associated with waist-hip ratio and reveals sexual dimorphism in the genetic basis of fat distribution
- 2010
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 42:11, s. 949-960
-
Tidskriftsartikel (refereegranskat)abstract
- Waist-hip ratio (WHR) is a measure of body fat distribution and a predictor of metabolic consequences independent of overall adiposity. WHR is heritable, but few genetic variants influencing this trait have been identified. We conducted a meta-analysis of 32 genome-wide association studies for WHR adjusted for body mass index (comprising up to 77,167 participants), following up 16 loci in an additional 29 studies (comprising up to 113,636 subjects). We identified 13 new loci in or near RSPO3, VEGFA, TBX15-WARS2, NFE2L3, GRB14, DNM3-PIGC, ITPR2-SSPN, LY86, HOXC13, ADAMTS9, ZNRF3-KREMEN1, NISCH-STAB1 and CPEB4 (P = 1.9 × 10⁻⁹ to P = 1.8 × 10⁻⁴⁰) and the known signal at LYPLAL1. Seven of these loci exhibited marked sexual dimorphism, all with a stronger effect on WHR in women than men (P for sex difference = 1.9 × 10⁻³ to P = 1.2 × 10⁻¹³). These findings provide evidence for multiple loci that modulate body fat distribution independent of overall adiposity and reveal strong gene-by-sex interactions.
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| 11. |
- 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
-
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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| 12. |
- Jansson, Agneta, 1973-, et al.
(författare)
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A new polymorphism in the coding region of exon four in HSD17B2 in relation to risk of sporadic and hereditary breast cancer
- 2007
-
Ingår i: Breast Cancer Research and Treatment. - : Springer Science and Business Media LLC. - 0167-6806 .- 1573-7217. ; 106:1, s. 57-64
-
Tidskriftsartikel (refereegranskat)abstract
- In situ synthesis of oestrogens is of great importance in the development and progression of breast cancer. 17β-hydroxysteroid dehydrogenase (17HSD) type 2 catalyses oxidation from oestradiol to oestrone, and thereby protects the breast epithelial cells from oestradiol. Low expression of 17HSD type 2 has been associated with decreased survival in breast cancer, but no studies have investigated the mechanism behind the low expression. The 17HSD type 2 gene (HSD17B2) was screened for mutations with Single Stranded Conformation Polymorphism (SSCP)-DNA sequencing in 59 sporadic breast cancer cases, 19 hereditary breast cancer cases and seven breast cancer cell lines. DNA samples from 226 healthy individuals were used to identify if changes were previously unknown polymorphisms. No mutation was detected and therefore mutations in HSD17B2 do not explain why some breast tumours exhibit low 17HSD type 2 expression. However, a previously unknown polymorphism was found in exon four (Met226Val). Using molecular modelling, we found that the substituted residue is located at the outer part of the steroid binding site, probably causing minor alterations in the substrate binding. We further studied if the polymorphism contributes to breast cancer susceptibility in a larger material, but did not find an increased risk in the group of 317 sporadic breast cancer patients, 188 breast cancer patients with two close relatives with breast cancer or 122 hereditary breast cancer patients, compared to the healthy control group. We suggest that the detected polymorphism does not contribute to a higher risk of developing breast cancer.
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| 13. |
- Jansson, Anette, et al.
(författare)
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Dry Anaerobic Digestion of Food and Paper Industry Wastes at Different Solid Contents
- 2019
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Ingår i: Fermentation. - : MDPI. - 2311-5637. ; 5:2, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- A large volume of food is being wasted every year, while the pulp and paper industry also generate a large amount of solid wastes on a daily basis, causing environmental challenges around the world. Dry anaerobic digestion (AD) of these solid wastes is a cost-effective method for proper management. However, dry digestion of these waste streams has been restricted due to their complex structure, the presence of possible inhibitors and inappropriate operating conditions. In light of this fact, dry digestion of food waste (FW) and paper wastes (PW) was conducted at different total solid (TS) concentrations of reactor mixtures of 14%, 16%, 18% and 20% TS, corresponding to substrate to inoculum (S/I) ratio of 0.5 and 1; investigating the optimum operating conditions for effective dry digestion of these complex wastes. The highest methane yields of 402 NmlCH(4)/gVS and 229 NmlCH(4)/gVS were obtained from digestion of FW and PW, respectively at 14%TS corresponding to an S/I ratio of 0.5. Increasing the S/I ratio from 0.5 to 1 and thereby having a TS content of 20% in the reactor mixtures was unfavorable to the digestion of both substrates.
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| 14. |
- Jansson, Anette, et al.
(författare)
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Effect of organic compounds on dry anaerobic digestion of food and paper industry wastes
- 2020
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Ingår i: Bioengineered. - : Taylor & Francis Group. - 2165-5979 .- 2165-5987. ; 11:1, s. 502-509
-
Tidskriftsartikel (refereegranskat)abstract
- Effects of antimicrobial compounds on dry anaerobic digestion (dry-AD) processes were investigated. Four compounds with known inhibition effects on traditional wet digestion, i.e. car-3-ene, hexanal, 1-octanol and phenol were selected and investigated at concentrations of 0.005%, 0.05% and 0.5%. Food waste (FW) and Paper waste (PW) were used as model substrates, all assays were running with the substrate to inoculum ratio of 1:1 (VS basis) corresponding to 15% TS in reactors. Generally, increasing concentrations of inhibitors resulted in decreasing methane yields with a few exceptions; in all these specific cases, long, lag phase periods (60 days) were observed. These adaptation periods made possible for the microbial systems to acclimatize to otherwise not preferred conditions leading to higher methane yields. Comparing the effects of the four different groups, phenols had the highest inhibitory effects, with no methane production at the highest amount added, while the lowest effects were obtained in cases of car-3-ene. Furthermore, the results showed that adding inhibitors up to a certain concentrations can repair the balance in AD process, slowing down the degradation steps, hence making it possible for the methanogens to produce a higher amount of methane. This phenomenon was not observed in case of PW, which is already a slow degradable substrate in its nature.
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| 15. |
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| 16. |
- Jansson, Anette M, 1963
(författare)
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Analysis and design methods for fibre reinforced concrete: a state-of-the-art report
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- During the past decades the concrete construction field has experienced a growing interest in the advantages fibre reinforcement has to offer. Of the different fibres available, e.g. steel, synthetic and glass fibres, the steel fibre is the most investigated and most commonly used. Fibre reinforcement today is mainly used in applications such as sprayed concrete, industrial floors and overlays, although other application areas exist. Some of the potential benefits from the adding of fibres to concrete are improved crack control and more slender constructions. The extent of the crack control depends on the amount of fibres added, and plays a great role for durability. As of today there exist no generally accepted design- and analysis procedures, and if the technique with fibres is to move forward, there is a need for development of such methods. Several technical committees have proposed design methods based on a stress-strain relationship, but also methods based on a stress-crack width relationship are proposed. Different methods for analysis of fibre reinforced concrete structural members are also proposed by several researchers. Comparison and evaluation of these methods, will provide a base for further research aiming at improvement of the, at the moment, available methods. It is found that for design, the Italian proposal provides a comprehensive method taking a step in the right direction considering the different ways of determining the characteristic length (for translating crack-width into strain). An improvement though, would be if the formula for calculation of crack width/crack spacing were to be modified according to a proposal made by Löfgren, see Gustafsson and Karlsson (2006). Regarding analysis, all the reviewed methods yield good results in comparison with experiments described in the reviewed articles.
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| 17. |
- Jansson, Anette M, 1963, et al.
(författare)
-
Applying a fracture mechanics approach on FRC beams, material testing and structural analysis
- 2008
-
Ingår i: Submitted to Journal of Advanced Concrete Technology.
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The presented work has been focused on strain-softening FRC and the interrelationship between material properties and structural behaviour. The main purpose of this work was to establish a procedure for structural analysis of flexural members with a combination of steel fibres and conventional reinforcement. A systematic approach for material testing and structural analysis, based on fracture mechanics, has been used and this covers: (1) material testing; (2) inverse analysis; (3) adjustment of the -w relationship for fibre efficiency; and (4) cross-sectional and structural analysis. The results suggest that the approach used for the material testing provides the necessary properties to perform analyses based on non-linear fracture mechanics. The structural behaviour could be predicted with good agreement with FEM using both bi-linear and multi-linear -w relationships. When comparing the peak loads obtained in the experiments with the results from the analyses, the agreement was good, with a high correlation. This demonstrates the strength of the fracture-mechanics approach for material testing and structural analysis.
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| 18. |
- Jansson, Anette M, 1963, et al.
(författare)
-
Applying a fracture mechanics approach to material testing and structural analysis of FRC beams
- 2007
-
Ingår i: Conference proceedings for FRAMCOS-6, Catania, Italy June 2007. ; , s. 1491-1496
-
Konferensbidrag (refereegranskat)abstract
- The presented work has been focused on strain-softening FRC and the interrelationship between material properties and structural behaviour. The main purpose of this work was to establish a procedure for structural analysis of flexural members with a combination of conventional reinforcement and steel fibres. A systematic approach for material testing and structural analysis, based on fracture mechanics has been used, this covers: (1) material testing; (2) inverse analysis; (3) adjustment of the -w relationship for fibre efficiency; and (4) cross-sectional and structural analysis. The results suggest that the approach used for the material testing provides the necessary properties to perform analyses based on non-linear fracture mechanics. The structural behaviour could be predicted with good agreement, using both FEM and an analytical model, and when comparing the peak loads obtained in the experiments with the results from the analyses, the agreement was good, with a high correlation. Hence, this demonstrates the strength of the fracture-mechanical approach for material testing and structural analysis.
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| 19. |
- Jansson, Anette M, 1963, et al.
(författare)
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Bond between Reinforcement and Self-Compacting Steel-Fibre-Reinforced Concrete
- 2012
-
Ingår i: Proceeding of the Fourth International Conference on Bond in Concrete 2012: Bond, Anchorage, Detailing. ; 1, s. 323-329
-
Konferensbidrag (refereegranskat)abstract
- In this study, pull-out tests of specimens with short embedment length and varying fibre content were carried out. The results showed no effect from the fibres on the bond-slip behaviour before peak load when normalized with respect to the compressive strength. After peak, the fibre reinforcement provided extra confinement, changing the failure mode from splitting to pull-out failure. The test results were used to calibrate a frictional bond model in non-linear finite element analyses. The model proved to yield results in good agreement with the experimental results regarding failure modes, load-slip relation and splitting strains on the surfaces of the pull-out specimens. The tests and analyses in combination confirmed that the fibre reinforcement neither disturbed nor improved the bond properties at the interface layer between reinforcement steel and concrete; i.e. the fibres only provided confinement to the surrounding structure.
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| 20. |
- Jansson, Anette M, 1963, et al.
(författare)
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Bond of reinforcement in self-compacting steel-fibre-reinforced concrete
- 2012
-
Ingår i: Magazine of Concrete Research. - : Thomas Telford Ltd.. - 0024-9831 .- 1751-763X. ; 64:7, s. 617-630
-
Tidskriftsartikel (refereegranskat)abstract
- Crack control, one of the main benefits of using fibre reinforcement, depends to a large extent on the concrete-rebar bond. Pull-out tests of specimens with short embedment length were carried out and the results showed no effect from the fibres on the normalised bond-slip behaviour before peak load. After this, the fibre reinforcement provided extra confinement, changing the failure mode from splitting to pull-out failure. The test results were used to calibrate a finite-element bond model that considers both tangential stresses and stresses in the radial direction from the rebar. Splitting cracks may be thus considered in the finite-element analyses. The model proved to yield results in good agreement with the experimental results regarding failure mode, load-slip relation and splitting strains on the surfaces of the pull-out specimens. The analyses revealed that two types of action were active in the cracking process. In addition, the confinement effect of the fibre reinforcement was compared with the confinement of conventional stirrups using the bond model in CEB-FIP model code 2010.
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| 21. |
- Jansson, Anette M, 1963, et al.
(författare)
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Design methods of fibre reinforced concrete: a state-of-the-art review
- 2008
-
Ingår i: Submitted to Nordic Concrete Research.
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The increasing interest in the use of fibre reinforcement has created a need for established design and analysis methods. Fibre reinforcement is mainly used in applications such as industrial floors and sprayed concrete, although other application areas exist. Apart from increased load carrying capacity, one of the main benefits of adding fibres to concrete is the potential reduction in crack width, which depends on the amount of fibres added and positively affects the durability of the finished structure. By comparing ten design methods proposed by technical committees, this paper provides a basis for further research aimed at developing a common design basis. Evaluation is based on the way the fibre capacity is considered. In addition, a “good” design method should also consider all (or most) design situations. It was found that, for design, the Italian proposal provides comprehensiveness. However, some amendments are needed, e.g. a suggestion is that the proposed formula for calculating crack width/crack spacing be modified to also consider the residual tensile strength.
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| 22. |
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| 23. |
- Jansson, Anette M, 1963
(författare)
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Effects of Steel Fibres on Cracking in Reinforced Concrete
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ABSTRACTAlthough it is well known that fibre reinforcement acts as a crack arresting agent, there is still a need for deeper knowledge of the actual cracking behaviour, especially regarding cracks with widths smaller than 0.3mm. Today major fibre applications are as a replacement for the welded mesh in industrial floors, and as reinforcement in sprayed concrete. However, other applications exist and are investigated.By combining experiments with finite-element analyses, the effects of fibres on cracking in conventionally reinforced, self-compacting, steel-fibre-reinforced concrete (SCSFRC) were studied. When studying the beginning of the cracking process, the tensile softening behaviour (-w relationship), and the bond stress-slip behaviour, which are the ones mainly affecting the cracking, are clearly of interest. Contradictory information on the effect of fibres on bond behaviour was found in the literature. Pull-out tests with short embedment length were thus carried out. The -w relationship may be obtained indirectly by inverse analysis, e.g. from wedge-splitting tests, or directly, from uniaxial tension tests (UTT); both approaches were used in this work. To investigate the cracking process, tension tests of tie elements were carried out, where, in addition to the load-deformation curves, a full-field strain measuring technique using Digital Image Correlation (DIC) was used to monitor the surface cracking.It was found from the pull-out tests that, for the type and amount of fibres used here, the bond properties at the interface layer were neither reduced nor improved. There were indications, however, that the initial stiffness of the bond stress-slip curves was increased by the self-compacting concrete. The UTT and the tie element testing showed that the scatter was quite high regarding the number of fibres in a cut cross section. It was seen that fibre reinforcement markedly improves tension stiffening and, at a given load, the characteristic crack width is greatly reduced compared with plain concrete. The DIC gave good insight into the surface crack initiation and enabled the tension stiffening to be quantified by relating it to the characteristic crack widths. In addition, it was seen that the cracking load and first-peak tensile stress increased with an increasing amount of fibres.The Finite element analyses of the beams and the tie elements revealed that the methodology used was versatile. It was found that the smeared crack model did not yield crack localization for materials with high fibre content (Vf > 0.5%) if homogenous material properties were assumed. Instead a semi-meso approach was used; properties for plain concrete were assigned to randomly designated parts of the elements, while the remaining elements were assigned modified tensile properties. The modified properties were increased so that the average -w curve of one cross section corresponded to the average curve from the UTT. With the new approach, the load-elongation response agreed better with the experiments; crack localization was obtained and crack widths could be reasonably reproduced.
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| 24. |
- Jansson, Anette M, 1963, et al.
(författare)
-
Experimental investigation of surface crack initiation, propagation and tension stiffening in self-compacting steel–fibre-reinforced concrete
- 2012
-
Ingår i: Materials and Structures. - : Springer Science and Business Media LLC. - 1359-5997 .- 1871-6873. ; 45:8, s. 1127-1143
-
Tidskriftsartikel (refereegranskat)abstract
- To investigate crack initiation and propagation in reinforced, self-compacting, steel–fibre-reinforced concrete (SCSFRC) members, tie elements were tested in tension. Strain and surface crack formation were monitored with an optical strain measurement system based on digital image correlation. In addition, to capture the softening behaviour (s–w) of the material, uni-axial tension testing was performed on SCSFRC cylinders. The results show that, with the optical strain measurement system, it was possible to detect different cracking modes and to follow the crack growth. It was especially of interest to recognize that high fibre amounts tend to change a sudden opening of a crack (as in non-fibrous concrete) into a more stable procedure. It was found that, for a given crack width, the SCSFRC specimens exhibited a noticeably higher tension stiffening than the specimens without fibres. Moreover, at a given load, the crack widths decreased by as much as 65% for the SCSFRC specimens with a nominal fibre content of 1%. For the uni-axial tension tests the results showed that with higher fibre content, for this type of fibre and concrete, both the peak stress and the residual tensile stress were increased. Additionally, it was noted for both specimen types that the scatter in fibre distribution decreased with increasing fibre content.
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| 25. |
- Jansson, Anette M, 1963
(författare)
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Fibres in reinforced concrete structures - analysis, experiments and design
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Potential benefits from fibres in concrete are improved crack control and the possibility of more slender structures. The extent of the crack control depends, among other factors, on the amount of fibres added, and plays a great role for durability. As of today there exist no generally accepted design and analysis procedures, and if the technique with fibres is to move forward, there is a need for development of such methods. As a part of the present work, an investigation of currently available design methods (proposed) was made. In addition a selection of analysis methods for fibre-reinforced concrete specimens in bending was studied. The main characteristics and comparisons of the investigated design and analysis methods are presented in a report Jansson (2007), and also in an article based on the report, Jansson (2008).Although several technical committees have proposed design methods, these methods are mainly intended for design in the ultimate limit state (ULS). Therefore, in order to control and understand crack growth in fibre-reinforced concrete, methods aimed at serviceability limit state design are needed.The present work has been carried out with this in mind and the aim, in the long run, is to develop a method which can be used to predict crack widths, i.e. small crack widths relevant for the serviceability limit state (SLS). The work includes experimental evaluation in the form of four-point beam-bending tests to investigate flexural behaviour and wedge-splitting tests to obtain material properties in the form of a stress-crack opening (σ-w) relationship. Finite element analyses (FEA) of the tested beams were performed. This is the tool which, in combination with fracture mechanics, is believed to have the potential to provide the desired results regarding crack-width prediction.From the work presented here, the FEA results indicate that a rather simplified (σ-w) relationship is sufficient for calculations in the ULS, while for the SLS a more refined σ-w) relationship may be required. The multi-linear (σ-w) relationship, which was investigated and used in the present work, appears to yield more accurate results during the early stage of the analysis, i.e. the cracking stage.
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| 26. |
- Jansson, Anette M, 1963, et al.
(författare)
-
Flexural Behaviour of members with a combination of steel fibres and conventional reinforcement
- 2010
-
Ingår i: Nordic Concrete Research. - 0800-6377. ; 2/2010:42, s. 155-171
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of the presented work was to investigate the flexural behaviour of members with a combination of steel fibres and conventional reinforcement. A systematic approach for material testing and structural analysis, based on fracture mechanics, was used and covers (1) material testing, (2) inverse analysis and (3) structural analysis based on FEM. In addition, the average crack spacing from the FE analyses was compared with experimental results and with two analytical approaches. The results suggest that the approach used for the material testing provides the properties necessary to perform analyses based on non-linear fracture mechanics. The structural behaviour could be predicted with good agreement with FEM using both bi-linear and multi-linear stress-crack opening (-w) relationships. When comparing peak loads obtained in the experiments with results from the analyses, the agreement was good. The crack spacing from the experiments was predicted with good agreement using both the analytical approach by Löfgren and the multi-linear FE approach.
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| 27. |
- Jansson, Anette M, 1963, et al.
(författare)
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MATERIAL TESTING AND STRUCTURAL ANALYSIS OF FRC BEAMS - AFRACTURE MECHANICS APPROACH
- 2008
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Ingår i: Conference proceedings - Befib, Chennai India, Sept 2008.
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Konferensbidrag (refereegranskat)abstract
- AbstractThe presented work has been focused on strain-softening FRC and the interrelationshipbetween material properties and structural behaviour. The main purpose of this work was toestablish a procedure for structural analysis of flexural members with a combination of steelfibres and conventional reinforcement. A systematic approach for material testing andstructural analysis, based on fracture mechanics, has been used and this covers: (1) materialtesting; (2) inverse analysis; (3) adjustment of the s-w relationship for fibre efficiency; and(4) cross-sectional and structural analysis. The results suggest that the approach used for thematerial testing provides the necessary properties to perform analyses based on non-linearfracture mechanics. The structural behaviour could be predicted with good agreement withFEM using both bi-linear and multi-linear s-w relationships. When comparing the peak loadsobtained in the experiments with the results from the analyses, the agreement was good, witha high correlation. This demonstrates the strength of the fracture-mechanics approach formaterial testing and structural analysis.
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| 28. |
- Jansson, Anette, et al.
(författare)
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Pilot-Scale Experiments Using Cultivated Macro Algae for Biogas Production, Part of a Future Seafarm Biorefinery
- 2016
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Ingår i: 24th EUBCE Online Proceedings 2016. - : ETA-Florence Renewable Energies. - 9788889407165 ; , s. 627-629
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Konferensbidrag (refereegranskat)abstract
- The research is focused on evaluation of substrates not commonly used for biogas production and the development and optimization of processes adjusted to these substrates. This study deals with evaluation of sea weeds (Saccharina Lattisima and Laminaria digitata). Biomethane potential tests (BMP) have shown the methane potential of the algae to be 180-440 l CH4/kg organic material. These potentials are in the same range as potentials found for commonly used substrates such as sewage sludge and slaughterhouse waste. Sampling of produced biogas, substrate and digest were performed by using Solid Phase Microextraction (SPME) followed by analysis by a Gas Chromatograph with a Mass Spectrometrer (GC-MS) in order to develop a method to be able to characterize, monitor and possibly control the process.
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| 29. |
- Jansson, Malin, et al.
(författare)
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Prognostic Value of Stromal Type IV Collagen Expression in Small Invasive Breast Cancers
- 2022
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Ingår i: Frontiers in Molecular Biosciences. - : Frontiers Media SA. - 2296-889X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Breast cancer is the most common cause of cancer death among women worldwide. Localized breast cancer can be cured by surgery and adjuvant therapy, but mortality remains high for tumors that metastasize early. Type IV collagen is a basement membrane protein, and breach of this extracellular matrix structure is the first step of cancer invasion. Type IV collagen is found in the stroma of many cancers, but its role in tumor biology is unclear. Here, expression of type IV collagen in the stroma of small breast cancers was analyzed, correlated to clinically used prognostic biomarkers and patient survival. The findings were further validated in an independent gene expression data cohort. Tissue samples from 1,379 women with in situ and small invasive breast cancers (<= 15 mm) diagnosed in 1986-2004 were included. Primary tumor tissue was collected into tissue microarrays. Type IV collagen expression in tissues was visualized using immunohistochemistry. Gene expression data was extracted from the Cancer Genome Atlas database. Out of 1,379 women, 856 had an invasive breast cancer and type IV collagen staining was available for 714 patients. In Kaplan-Meier analysis high type IV collagen expression was significantly associated (p = 0.026) with poorer breast cancer specific survival. There was no correlation of type IV collagen expression to clinically used prognostic biomarkers. High type IV collagen expression was clearly associated to distant metastasis (p = 0.002). In an external validation cohort (n = 1,104), high type IV collagen mRNA expression was significantly (p = 0.041) associated with poorer overall survival, with overexpression of type IV collagen mRNA in metastatic tissue. Stromal type IV collagen expression in the primary tumor correlates to poor breast cancer specific survival most likely due to a higher risk of developing distant metastasis. This ECM protein may function as biomarker to predict the risk of future metastatic disease in patients with breast cancers.
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| 30. |
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| 31. |
- Jansson, Malin, 1978-, et al.
(författare)
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Stromal type I collagen in breast cancer : correlation to prognostic biomarkers and prediction of chemotherapy response
- 2024
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Ingår i: Clinical Breast Cancer. - : Elsevier. - 1526-8209 .- 1938-0666.
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Fibrillar collagens accumulate in the breast cancer stroma and appear as poorly defined spiculated masses in mammography imaging. The prognostic value of tissue type I collagen remains elusive in treatment-naïve and chemotherapy-treated breast cancer patients. Here, type I collagen mRNA and protein expression were analysed in 2 large independent breast cancer cohorts. Levels were related to clinicopathological parameters, prognostic biomarkers, and outcome.Method: COL1A1 mRNA expression was analysed in 2509 patients with breast cancer obtained from the cBioPortal database. Type I collagen protein expression was studied by immunohistochemistry in 1395 women diagnosed with early invasive breast cancer.Results: Low COL1A1 mRNA and protein levels correlated with poor prognosis features, such as hormone receptor negativity, high histological grade, triple-negative subtype, node positivity, and tumour size. In unadjusted analysis, high stromal type I collagen protein expression was associated with improved overall survival (OS) (HR = 0.78, 95% CI = 0.61-0.99, p = .043) and trended towards improved breast cancer–specific survival (BCSS) (HR = 0.65, 95% CI = 0.42-1.01, P = 0.053), although these findings were lost after adjustment for other clinical variables. In unadjusted analysis, high expression of type I collagen was associated with better OS (HR = 0.70, 95% CI = 0.55-0.90, P = .006) and BCSS (HR = 0.55, 95% CI = 0.34-0.88, P = .014) among patients not receiving chemotherapy. Strikingly, the opposite was observed among patients receiving chemotherapy. There, high expression of type I collagen was instead associated with worse OS (HR = 1.83, 95% CI = 0.65-5.14, P = .25) and BCSS (HR = 1.72, 95% CI = 0.54-5.50, P = .357).Conclusion: Low stromal type I collagen mRNA and protein expression are associated with unfavourable tumour characteristics in breast cancer. Stromal type I collagen might predict chemotherapy response.
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| 32. |
- Magnusson-Olsson, AnneLiese, et al.
(författare)
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Gestational and hormonal regulation of human placental lipoprotein lipase
- 2006
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Ingår i: J Lipid Res. ; 47:11, s. 2551-61
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Tidskriftsartikel (refereegranskat)abstract
- The fetal demand for FFA increases as gestation proceeds, and LPL represents one potential mechanism for increasing placental lipid transport. We examined LPL activity and protein expression in first trimester and term human placenta. The LPL activity was 3-fold higher in term (n = 7; P < 0.05) compared with first trimester (n = 6) placentas. The LPL expression appeared lower in microvillous membrane from first trimester (n = 2) compared with term (n = 2) placentas. We incubated isolated placental villous fragments with a variety of effectors [GW 1929, estradiol, insulin, cortisol, epinephrine, insulin-like growth factor-1 (IGF-1), and tumor necrosis factor-alpha] for 1, 3, and 24 h to investigate potential regulatory mechanisms. Decreased LPL activity was observed after 24 h of incubation with estradiol (1 micro g/ml), insulin, cortisol, and IGF-1 (n = 12; P < 0.05). We observed an increase in LPL activity after 3 h of incubation with estradiol (20 ng/ml) or hyperglycemic medium plus insulin (n = 7; P < 0.05). To conclude, we suggest that the gestational increase in placental LPL activity represents an important mechanism to enhance placental FFA transport in late pregnancy. Hormonal regulation of placental LPL activity by insulin, cortisol, IGF-1, and estradiol may be involved in gestational changes and in alterations in LPL activity in pregnancies complicated by altered fetal growth.
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| 33. |
- Marouli, Eirini, et al.
(författare)
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Rare and low-frequency coding variants alter human adult height
- 2017
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 542:7640, s. 186-190
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Tidskriftsartikel (refereegranskat)abstract
- Height is a highly heritable, classic polygenic trait with approximately 700 common associated variants identified through genome-wide association studies so far. Here, we report 83 height-associated coding variants with lower minor-allele frequencies (in the range of 0.1-4.8%) and effects of up to 2 centimetres per allele (such as those in IHH, STC2, AR and CRISPLD2), greater than ten times the average effect of common variants. In functional follow-up studies, rare height increasing alleles of STC2 (giving an increase of 1-2 centimetres per allele) compromised proteolytic inhibition of PAPP-A and increased cleavage of IGFBP-4 in vitro, resulting in higher bioavailability of insulin-like growth factors. These 83 height-associated variants overlap genes that are mutated in monogenic growth disorders and highlight new biological candidates (such as ADAMTS3, IL11RA and NOX4) and pathways (such as proteoglycan and glycosaminoglycan synthesis) involved in growth. Our results demonstrate that sufficiently large sample sizes can uncover rare and low-frequency variants of moderate-to-large effect associated with polygenic human phenotypes, and that these variants implicate relevant genes and pathways.
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| 34. |
- Pechsiri, Joseph Santhi, et al.
(författare)
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Energy performance and greenhouse gas emissions of kelp cultivation for biogas and fertilizer recovery in Sweden
- 2016
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 573, s. 347-355
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Tidskriftsartikel (refereegranskat)abstract
- The cultivation of seaweed as a feedstock for third generation biofuels is gathering interest in Europe, however, many questions remain unanswered in practise, notably regarding scales of operation, energy returns on investment (EROI) and greenhouse gas (GHG) emissions, all of which are crucial to determine commercial viability. This study performed an energy and GHG emissions analysis, using EROI and GHG savings potential respectively, as indicators of commercial viability for two systems: the Swedish Seafarm project's seaweed cultivation (0.5 ha), biogas and fertilizer biorefinery, and an estimation of the same system scaled up and adjusted to a cultivation of 10 ha. Based on a conservative estimate of biogas yield, neither the 0.5 ha case nor the up-scaled 10 ha estimates met the (commercial viability) target EROI of 3, nor the European Union Renewable Energy Directive GHG savings target of 60% for biofuels, however the potential for commercial viability was substantially improved by scaling up operations: GHG emissions and energy demand, per unit of biogas, was almost halved by scaling operations up by a factor of twenty, thereby approaching the EROI and GHG savings targets set, under beneficial biogas production conditions. Further analysis identified processes whose optimisations would have a large impact on energy use and emissions (such as anaerobic digestion) as well as others embodying potential for further economies of scale (such as harvesting), both of which would be of interest for future developments of kelp to biogas and fertilizer biorefineries.
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| 35. |
- Rudbeck Jepsen, Martin, et al.
(författare)
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Transitions in European land-management regimes between 1800 and 2010
- 2015
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Ingår i: Land use policy. - : Elsevier BV. - 0264-8377 .- 1873-5754. ; 49:SI, s. 53-64
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Tidskriftsartikel (refereegranskat)abstract
- Land use is a cornerstone of human civilization, but also intrinsically linked to many global sustainability challenges—from climate change to food security to the ongoing biodiversity crisis. Understanding the underlying technological, institutional and economic drivers of land-use change, and how they play out in different environmental, socio-economic and cultural contexts, is therefore important for identifying effective policies to successfully address these challenges. In this regard, much can be learned from studying long-term land-use change. We examined the evolution of European land management over the past 200 years with the aim of identifying (1) key episodes of changes in land management, and (2) their underlying technological, institutional and economic drivers. To do so, we generated narratives elaborating on the drivers of land use-change at the country level for 28 countries in Europe. We qualitatively grouped drivers into land-management regimes, and compared changes in management regimes across Europe. Our results allowed discerning seven land-management regimes, and highlighted marked heterogeneity regarding the types of management regimes occurring in a particular country, the timing and prevalence of regimes, and the conditions that result in observed bifurcations. However, we also found strong similarities across countries in the timing of certain land-management regime shifts, often in relation to institutional reforms (e.g., changes in EU agrarian policies or the emergence and collapse of the Soviet land management paradigm) or to technological innovations (e.g., drainage pipes, tillage and harvesting machinery, motorization, and synthetic fertilizers). Land reforms frequently triggered changes in land management, and the location and timing of reforms had substantial impacts on land-use outcomes. Finally, forest protection policies and voluntary cooperatives were important drivers of land-management changes. Overall, our results demonstrate that land-system changes should not be conceived as unidirectional developments following predefined trajectories, but rather as path-dependent processes that may be affected by various drivers, including sudden events.
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| 36. |
- Scandurra, Isabella, 1973-, et al.
(författare)
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Is 'patient's online access to health records' a good reform? : Opinions from Swedish healthcare professionals differ
- 2015
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Ingår i: Conference On Enterprise Information Systems/International Conference On Project Management/Conference On Health And Social Care Information Systems And Technologies, Centeris/Projman / Hcist 2015. - Amsterdam, Netherlands : Elsevier BV. ; 64, s. 964-968
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Konferensbidrag (refereegranskat)abstract
- Patients' access to their own electronic health record is a controversial issue. Many care professionals are concerned about negative effects deriving from patients reading their record information without support from clinicians. Patients on the other hand often think their concerns are outweighed by the benefits. In Sweden a pilot county has provided the health record online to its 350 000 patients for 2.5 years. This study highlights one of the most important questions to handle before and during implementation of such public eHealth services; the opinions of the care professionals regarding online records as a good reform. Results from three questionnaires to various care professions show that opinions from healthcare professionals differ not only between the professions but more importantly also between those who have experience from their patients reading their health record online and those who to date have no real experience. The experienced staff was more positive. This study concludes that in order to provide for successful national implementation, it is important to quickly elicit and disseminate opinions of care professionals with real experience to their unexperienced peers. Healthcare professionals should also be more involved in the implementation of Public eHealth services that regard electronic health records and their work processes.
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| 37. |
- Scandurra, Isabella, 1973-, et al.
(författare)
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Patient Accessible EHR is Controversial : Lack of Knowledge and Diverse Perceptions Among Professions
- 2017
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Ingår i: International Journal of Reliable and Quality E-Healthcare. - : IGI Global. - 2160-9551 .- 2160-956X. ; 6:1, s. 29-46
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden, a national eHealth service providing Patient Accessible Electronic Health Records is now being widely deployed, with 400 000 users in January 2016. Although the Patient Data Act states that patients have a right to take part of their health records, the introduction has been controversial. Results from a pre-deployment questionnaire to record-keeping care professions in a healthcare region indicate that perceptions and knowledge differ not only between the professions but, more importantly, that knowledge about current eHealth development and action plans needs to increase as implementation will affect their work processes. Staff perceptions and knowledge are considered being some of the most important issues to handle during the implementation of eHealth services aiming to provide healthcare information and communication tools for patients and relatives. To cover the gaps, specific training is needed, and all record-keeping professionals need to be more involved in the implementation of such eHealth services.
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| 38. |
- Speliotes, Elizabeth K., et al.
(författare)
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Association analyses of 249,796 individuals reveal 18 new loci associated with body mass index
- 2010
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 42:11, s. 937-948
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ~2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10−8), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation.
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| 39. |
- Sundström, Johan, Professor, 1971-, et al.
(författare)
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Weight gain and blood pressure
- 2020
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Ingår i: Journal of Hypertension. - : Lippincott Williams & Wilkins. - 0263-6352 .- 1473-5598. ; 38:3, s. 387-394
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Although the causality of the obesity—hypertension association is established, the potential for prevention is not. We hypothesized that weight gain between early adulthood and mid-life is associated with higher mid-life blood pressure.METHODS: We investigated the hypothesis using a large contemporaneous population-based mid-life cohort of men and women aged 50-64 years. Recalled body weight at age 20 years was self-reported, and mid-life body weight and office blood pressures were measured in accordance with a detailed protocol.RESULTS: On average, men had gained 14.9 (95% CI 14.6-15.2) kg of weight, and women 14.6 (95% CI 14.4-14.9) kg, between age 20 years and the mid-life examination, corresponding to 0.40 (95% CI 0.39-0.41) kg/year for men and women. Both weight at age 20 years and weight at the mid-life examination were associated with mid-life blood pressures. On average, a 10 kg weight increase between age 20 years and mid-life was associated with 2.2 (95% CI 0.9-3.5) mmHg higher systolic and 1.7 (95% CI 0.9-2.5) mmHg higher diastolic mid-life blood pressure in men, and 3.2 (2.5-4.0) mmHg higher systolic and 2.4 (1.9-2.9) mmHg higher diastolic mid-life blood pressure in women. Mid-life weight was more closely associated than weight at age 20 years with mid-life blood pressure. For a given mid-life weight, blood pressure was higher in persons with higher weight gain from age 20 years.CONCLUSION: In sum, weight gain between early adulthood and mid-life was associated with higher mid-life blood pressure. The magnitude of the association indicates a potentially great public health impact of strategies to prevent weight gain throughout adulthood.
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| 40. |
- Wallin, Helena, et al.
(författare)
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Gradual reduction in exercise capacity in chronic kidney disease is associated with systemic oxygen delivery factors.
- 2018
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 13:12
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Tidskriftsartikel (refereegranskat)abstract
- The cause of reduced exercise capacity (ExCap) in chronic kidney disease (CKD) is multifactorial. The aim of this study was to investigate determinants of aerobic ExCap in patients with mild to severe CKD not undergoing dialysis.We included 52 individuals with CKD stage 2-3, 47 with stage 4-5, and 54 healthy controls. Peak workload and peak heart rate (HR) were assessed by a maximal cycle exercise test. Cardiac function including stroke volume (SV) and vascular stiffness were evaluated by ultrasound at rest. Handgrip strength, body composition, haemoglobin level and self-reported physical activity were assessed.Peak workload (221±60, 185±59, 150±54 W for controls, CKD 2-3 and CKD 4-5 respectively), peak HR (177±11, 161±24, 144±31 beats/min) and haemoglobin level (14.2±1.2, 13.5±1.4, 12.2±1.3 g/dL) were all three significantly lower in CKD 2-3 than in controls, (p = 0.001, 0.001 and 0.03 respectively) and were even lower in stages 4-5 CKD than in CKD 2-3 (p = 0.01, 0.001 and <0.001 respectively). Resting SV and lean body mass did not differ between groups and handgrip strength was significantly lower only in CKD 4-5 compared to controls (p = 0.02). Peak workload was strongly associated with the systemic oxygen delivery factors: SV, peak HR and haemoglobin level. These three factors along with age, sex and height2 explained 82% of variation in peak workload. Peak HR contributed most to the variation; the peripheral variables handgrip strength and vascular stiffness did not improve the explanatory value in regression analysis.In this cross-sectional study of CKD patients not on dialysis, aerobic ExCap decreased gradually with disease severity. ExCap was associated mainly with systemic oxygen delivery factors, in particular peak HR. Neither muscle function and mass, nor vascular stiffness were independent determinants of aerobic ExCap in this group of CKD patients.
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| 41. |
- Zidar, Josefina, 1982-, et al.
(författare)
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Environmental complexity buffers against stress-induced negative judgement bias in female chickens
- 2018
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Cognitive processes are often biased by emotions. In humans, affective disorders are accompanied by pessimistic judgement, while optimistic judgement is linked to emotional stability. Similar to humans, animals tend to interpret ambiguous stimuli negatively after experiencing stressful events, although the long-lasting impact on judgement bias has rarely been investigated. We measure judgement bias in female chicks (Gallus gallus domesticus) after exposure to cold stress, and before and after exposure to additional unpredictable stressors. Additionally, we explore if brain monoamines can explain differences in judgement bias. Chicks exposed to cold stress did not differ in judgement bias compared to controls, but showed sensitivity to additional stressors by having higher motivation for social reinstatement. Environmental complexity reduced stress-induced negative judgement bias, by maintaining an optimistic bias in individuals housed in complex conditions even after stress exposure. Moreover, judgement bias was related to dopamine turnover rate in mesencephalon, with higher activity in individuals that had a more optimistic response. These results demonstrate that environmental complexity can buffer against negative effects of additive stress and that dopamine relates to judgement bias in chicks. These results reveal that both internal and external factors can mediate emotionally biased judgement in animals, thus showing similarities to findings in humans.
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