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- Yi, Chuixiang, et al.
(författare)
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Climate control of terrestrial carbon exchange across biomes and continents
- 2010
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere across biomes and continents are lacking. Here we present data describing the relationships between net ecosystem exchange of carbon (NEE) and climate factors as measured using the eddy covariance method at 125 unique sites in various ecosystems over six continents with a total of 559 site-years. We find that NEE observed at eddy covariance sites is (1) a strong function of mean annual temperature at mid-and high-latitudes, (2) a strong function of dryness at mid-and low-latitudes, and (3) a function of both temperature and dryness around the mid-latitudinal belt (45 degrees N). The sensitivity of NEE to mean annual temperature breaks down at similar to 16 degrees C (a threshold value of mean annual temperature), above which no further increase of CO2 uptake with temperature was observed and dryness influence overrules temperature influence.
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| 2. |
- Idris, Shaza B., et al.
(författare)
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Biocompatibility of Polyester Scaffolds with Fibroblasts and Osteoblast-like Cells for Bone Tissue Engineering
- 2010
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Ingår i: Journal of bioactive and compatible polymers (Print). - : SAGE Publications. - 0883-9115 .- 1530-8030. ; 25:6, s. 567-583
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the in vitro cytotoxicity and cytocompatibility of the developed aliphatic polyester co-polymer scaffolds: poly(L-lactide-co-epsilon-caprolactone) and poly(L-lactide-co-1,5-dioxepan-2-one). The scaffolds were produced by solvent casting and particulate leaching, and tested by direct and indirect contact cytotoxicity assays on human osteoblast-like cells and mouse fibroblasts. Cell morphology was documented by light and scanning electron microscopy. Viability was assessed by the MTT, neutral red uptake, lactic dehydrogenase and apoptosis assays. Extraction tests confirmed that the scaffolds did not have a cytotoxic effect on the cells. The cells grew and spread well on the test scaffolds with good cellular attachment and viability. The scaffolds are noncytotoxic and biocompatible with the two cell types and warrant continued investigation as potential constructs for bone tissue engineering.
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| 3. |
- Idris, Shaza B., et al.
(författare)
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Global Gene Expression Profile of Osteoblast-Like Cells Grown on Polyester Copolymer Scaffolds
- 2011
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Ingår i: Tissue Engineering. Part A. - NEW ROCHELLE, NY : Mary Ann Liebert. - 1937-3341 .- 1937-335X. ; 17:21-22, s. 2817-2831
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Tidskriftsartikel (refereegranskat)abstract
- One of the principal goals in tissue engineering is to produce scaffold materials that will guide cells to differentiate and regenerate functional replacement tissue at the site of injury. Poly(l-lactide-co-1,5-dioxepan-2-one) [Poly(LLA-co-DXO)], a potential scaffolding material for bone tissue engineering, has high hydrophilicity. Previous in vitro studies using human osteoblast-like cells (HOBs) demonstrated greater cytocompatibility and enhanced osteogenic differentiation when HOBs were seeded onto Poly(LLA-co-DXO) compared to Poly(llactide) [P(LLA)] scaffolds. The aim of the study was to identify the gene expression profiles of HOBs obtained from alveolar bone and grown on Poly(LLA-co-DXO) biodegradable polymer scaffolds compared to P(LLA) one. Illumina HumanWG-6 v3.0 Expression BeadChips were used for the gene expression analysis. Several genes were found as differentially expressed at 24 h and at 21 days. Expression of genes related to cell adhesion, cytoskeleton, antiapoptosis, proliferation, and bone mineralization was influenced by adding the monomer 1,5-dioxepan-2-one to the l-lactide. Genes related to three biological pathways involving Integrin, Notch, and Ras were found to be upregulated. For selected genes, results were confirmed by quantitative reverse transcriptase– polymerase chain reaction. Further, calcium content analysis revealed a significant enhancement of calcium deposition on both tested scaffolds. This observation was confirmed by Von Kossa and Alizarin Red S staining. Findings of this study are relevant to a better understanding of the molecular mechanisms underlying the behavior of HOBs in bone regenerative procedure.
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| 6. |
- Sachse, D., et al.
(författare)
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The Accu-Chek Mobile blood glucose monitoring system used under controlled conditions meets ISO 15197 standards in the hands of diabetes patients
- 2012
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - London, United Kingdom : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 72:5, s. 374-379
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Tidskriftsartikel (refereegranskat)abstract
- Background. Self-monitoring of blood glucose is a cornerstone of diabetes management. The aim of this study was to evaluate the analytical quality and the ease of use of the Accu-Chek Mobile, a new glucose monitoring system designed for capillary blood testing by diabetic patients. Materials and methods. The performance of the Accu-Chek Mobile was evaluated both in the hands of a scientist and of diabetes patients. The designated comparative method was a hexokinase-based laboratory method (Architect ci8200). Diabetics (N = 88) with previous experience of self-testing were recruited for the study. Patient samples, containing glucose in concentrations mainly between similar to 4 and similar to 20 mmol/L, were analyzed in duplicates both on the Accu-Chek Mobile and with the comparative method. The patients answered a questionnaire about the ease of use of the meter. Results. The meter yields reproducible readings, with an imprecision CV <5% as required by the American Diabetes Association (ADA). Of the glucose concentrations obtained by both the scientist and the patients, more than 95% of the individual results were within +/- 20% of the comparative method, meeting the ISO 15197 accuracy goal, but not the stricter +/- 10% ADA goal. Conclusion. Accu-Chek Mobile is a user-friendly glucometer that in a normo- and hyperglycemic range fulfils the ISO 15197 accuracy requirement, also in the hands of diabetes patients.
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| 7. |
- Thoresen, Christian, et al.
(författare)
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Arousal Modulates Activity in the Medial Temporal Lobe during a Short-Term Relational Memory Task.
- 2011
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Ingår i: Frontiers in human neuroscience. - 1662-5161. ; 5, s. 177-
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effect of arousal on short-term relational memory and its underlying cortical network. Seventeen healthy participants performed a picture by location, short-term relational memory task using emotional pictures. Functional magnetic resonance imaging was used to measure the blood-oxygenation-level dependent signal relative to task. Subjects' own ratings of the pictures were used to obtain subjective arousal ratings. Subjective arousal was found to have a dose-dependent effect on activations in the prefrontal cortex, amygdala, hippocampus, and in higher order visual areas. Serial position analyses showed that high arousal trials produced a stronger primacy and recency effect than low arousal trials. The results indicate that short-term relational memory may be facilitated by arousal and that this may be modulated by a dose-response function in arousal-driven neuronal regions.
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| 8. |
- Thoresen, Christian, et al.
(författare)
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Frontotemporal hypoactivity during a reality monitoring paradigm is associated with delusions in patients with schizophrenia spectrum disorders
- 2014
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Ingår i: Cognitive Neuropsychiatry. - 1354-6805 .- 1464-0619. ; 19:2, s. 97-115
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Impaired monitoring of internally generated information has been proposed to be one component in the development and maintenance of delusions. The present study investigated the neural correlates underlying the monitoring processes and whether they were associated with delusions. Methods Twenty healthy controls and 19 patients with schizophrenia spectrum disorders were administrated a reality monitoring paradigm during functional magnetic resonance imaging. During encoding participants were instructed to associate a statement with either a presented (viewed condition) or an imagined picture (imagined condition). During the monitoring session in the scanner, participants were presented with old and new statements and their task was to identify whether a given statement was associated with the viewed condition, imagined condition, or if it was new. Results Patients showed significantly reduced accuracy in the imagined condition with performance negatively associated with degree of delusions. This was accompanied with reduced activity in the left dorsolateral prefrontal cortex and left hippocampus in the patient group. The severity of delusions was negatively correlated with the blood-oxygenation-level dependent response in the left hippocampus. Conclusions The results suggest that weakened monitoring is associated with delusions in patients with schizophrenia spectrum disorder, and that this may be mediated by a frontotemporal dysfunction.
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