| 1. |
- Fortes-Lima, Cesar A., PhD, 1985-, et al.
(författare)
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Population structure and admixture during the expansion of Bantu-speaking peoples across sub-Saharan Africa
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The migration of Bantu-speaking groups out of West Africa, thought to have started around 4 000 years ago, is known as the Bantu expansion. This movement of people changed the genetic landscape of sub-equatorial Africa. To investigate the demographic history and population structure in Bantu-speaking populations (BSP), we genotyped 1,740 individuals, including 1,487 Bantu speakers from 143 populations across 13 sub-Saharan African countries. We find patterns of fine-scale population structure that correlate with linguistics and geography. Bantu speakers received significant amounts of admixture through interaction with local groups from the regions that they expanded into. Spatial modeling indicated possible migration corridors during the Bantu-expansion. Inferences based on modern-day genomes, however, need to be supported by ancient DNA studies. We demonstrated the utility of our dataset as an exhaustive modern-day African comparative dataset for ancient DNA studies by comparing our data to published aDNA studies. By gathering the largest set of genome-wide data to date, enriched with new data from previously unsampled regions and people, we shed new light on the intricacies of the Bantu expansion.
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| 2. |
- Fortes-Lima, Cesar A., PhD, 1985-, et al.
(författare)
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The genetic legacy of the expansion of Bantu-speaking peoples in Africa
- 2024
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 625:7995, s. 540-547
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Tidskriftsartikel (refereegranskat)abstract
- The expansion of people speaking Bantu languages is the most dramatic demographic event in Late Holocene Africa and fundamentally reshaped the linguistic, cultural and biological landscape of the continent1-7. With a comprehensive genomic dataset, including newly generated data of modern-day and ancient DNA from previously unsampled regions in Africa, we contribute insights into this expansion that started 6,000-4,000 years ago in western Africa. We genotyped 1,763 participants, including 1,526 Bantu speakers from 147 populations across 14 African countries, and generated whole-genome sequences from 12 Late Iron Age individuals8. We show that genetic diversity amongst Bantu-speaking populations declines with distance from western Africa, with current-day Zambia and the Democratic Republic of Congo as possible crossroads of interaction. Using spatially explicit methods9 and correlating genetic, linguistic and geographical data, we provide cross-disciplinary support for a serial-founder migration model. We further show that Bantu speakers received significant gene flow from local groups in regions they expanded into. Our genetic dataset provides an exhaustive modern-day African comparative dataset for ancient DNA studies10 and will be important to a wide range of disciplines from science and humanities, as well as to the medical sector studying human genetic variation and health in African and African-descendant populations.
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| 3. |
- Andersson, Linus, 1979-, et al.
(författare)
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Neurocognitive processes underlying heuristic and normative probability judgments
- 2020
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Ingår i: Cognition. - : ELSEVIER. - 0010-0277 .- 1873-7838. ; 196, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Judging two events in combination (A&B) as more probable than one of the events (A) is known as a conjunction fallacy. According to dual-process explanations of human judgment and decision making, the fallacy is due to the application of a heuristic, associative cognitive process. Avoiding the fallacy has been suggested to require the recruitment of a separate process that can apply normative rules. We investigated these assumptions using functional magnetic resonance imaging (fMRI) during conjunction tasks. Judgments, whether correct or not, engaged a network of brain regions identical to that engaged during similarity judgments. Avoidance of the conjunction fallacy additionally, and uniquely, involved a fronto-parietal network previously linked to supervisory, analytic control processes. The results lend credibility to the idea that incorrect probability judgments are the result of a representativeness heuristic that requires additional neurocognitive resources to avoid.
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| 4. |
- Dupuy, E., et al.
(författare)
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Strato-mesospheric Measurements of Carbon Monoxide with the Odin Sub-millimetre Radiometer: Retrieval and First Results
- 2004
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Ingår i: Geophysical Research Letters. - 1944-8007 .- 0094-8276. ; 31:20
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Tidskriftsartikel (refereegranskat)abstract
- The Sub-Millimetre Radiometer (SMR) aboard the Odin satellite has been measuring vertical profiles of atmospheric trace gases since August 2001. We present the inversion methodology developed for CO measurements and the first retrieval results. CO can be retrieved from a single scan measurement throughout the middle atmosphere, with a typical resolution of similar to3 km and a relative error of similar to10% to similar to25%. Retrieval results are evaluated through comparison with data from the Whole Atmosphere Community Climate Model (WACCM) and observations of the Improved Stratospheric and Mesospheric Sounder (ISAMS) on board the Upper Atmospheric Research Satellite (UARS). Considering the large natural variability of CO, the SMR retrievals give good confirmation of the WACCM results, with an overall agreement within a factor of 2. ISAMS abundances are higher than SMR mixing ratios by a factor of 5-10 above 0.5 hPa from similar to80degreesS to similar to50degreesN.
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| 5. |
- Eriksson, Peter, 1989-
(författare)
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Cerium Oxide Nanoparticles and Gadolinium Integration : Synthesis, Characterization and Biomedical Applications
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A challenging task, in the area of magnetic resonance imaging is to develop contrast enhancers with built-in antioxidant properties. Oxidative stress is considered to be involved in the onset and progression of several serious conditions such as Alzheimer’s and Parkinson’s disease, and the possibility to use cerium-contained nanoparticles to modulate such inflammatory response has gained a lot of interest lately. The rare earth element gadolinium is, due to its seven unpaired f-electrons and high symmetry of the electronic state, a powerful element for contrast enhancement in magnetic resonance imaging. Chelates based on gadolinium are the most commonly used contrast agents worldwide. When introducing external contrast agents there is always a risk that it may trigger inflammatory responses, why there is an urgent need for new, tailor-made contrast agents.Small sized cerium oxide nanoparticles have electronic structures that allows coexistence of oxidation states 3+ and 4+ of cerium, which correlates to applicable redox reactions in biomedicine. Such cerium oxide nanoparticles have recently shown to exhibit antioxidant properties both in vitro and in vivo, via the mechanisms involving enzyme mimicking activity.This PhD project is a comprehensive investigation of cerium oxide nanoparticles as scaffold materials for gadolinium integration. Gadolinium is well adopted into the crystal structure of cerium oxide, enabling the combination of diagnostic and therapeutic properties into a single nanoparticle. The main focus of this thesis project is to design cerium oxide nanoparticles with gadolinium integration. A stepwise approach was employed as follows: 1) synthesis with controlled integration of gadolinium, 2) material characterization by means of composition crystal structure, size, and size distribution and 3) surface modification for stabilization. The obtained nanoparticles exhibit remarkable antioxidant capability in vitro and in vivo. They deliver strongly enhanced contrast per gadolinium in magnetic resonance imaging, compared to commercially available contrast agents.A soft shell of dextran is introduced to encapsulate the cerium oxide nanoparticles with integrated gadolinium, which protects and stabilizes the hard core and to increases their biocompatibility. The dextran-coating is clearly shown to reduce formation of a protein corona and it improves the dispersibility of the nanoparticles in cell media. Functionalization strategies are currently being studied to endow these nanoparticles with specific tags for targeting purposes. This will enable guidance of the nanoparticles to a specific tissue, for high local magnetic resonance contrast complemented with properties for on-site reduced inflammation.In conclusion, our cerium oxide nanoparticles with integrated gadolinium, exhibit combined therapeutic and diagnostic, i.e. theragnostic capabilities. This type of nanomaterial is highly promising for applications in the field of biomedical imaging.
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| 6. |
- Malusek, Alexandr, 1968-, et al.
(författare)
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On The Possibility To Resolve Gadolinium- And Cerium-Based Contrast Agents From Their CT Numbers In Dual-Energy Computed Tomography
- 2021
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press. - 0144-8420 .- 1742-3406. ; 195:3-4, s. 225-231
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Tidskriftsartikel (refereegranskat)abstract
- Cerium oxide nanoparticles with integrated gadolinium have been proved to be useful as contrast agents in magnetic resonance imaging. Of question is their performance in dual-energy computed tomography. The aims of this work are to determine (1) the relation between the computed tomography number and the concentration of the I, Gd or Ce contrast agent and (2) under what conditions it is possible to resolve the type of contrast agent. Hounsfield values of iodoacetic acid, gadolinium acetate and cerium acetate dissolved in water at molar concentrations of 10, 50 and 100 mM were measured in a water phantom using the Siemens SOMATOM Definition Force scanner; gadolinium- and cerium acetate were used as substitutes for the gadolinium-integrated cerium oxide nanoparticles. The relation between the molar concentration of the I, Gd or Ce contrast agent and the Hounsfield value was linear. Concentrations had to be sufficiently high to resolve the contrast agents.
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| 7. |
- Roca Rubio, Maria Fernanda, 1989-, et al.
(författare)
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Associations between various markers of intestinal barrier and immune function after a high-intensity exercise challenge
- 2024
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Ingår i: Physiological Reports. - : John Wiley & Sons. - 2051-817X. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Strenuous exercise can result in disruption of intestinal barrier function and occurrence of gastrointestinal symptoms. The aim of this exploratory study was to elucidate systemic effects of increased intestinal permeability after high-intensity exercise. Forty-one endurance-trained subjects performed a 60-min treadmill run at 80% VO2max. Small intestinal permeability was measured as urinary excretion ratio of lactulose/rhamnose (L/R). Blood, saliva and feces were analyzed for gut barrier and immune-related biomarkers. The exercise challenge increased several markers of intestinal barrier disruption, immune function and oxidative stress. We found a negative correlation between L/R ratio and uric acid (r = -0.480), as well as a positive correlation between the L/R ratio and fecal chromogranin A in male participants (r = 0.555). No significant correlations were found between any of the markers and gastrointestinal symptoms, however, perceived exertion correlated with the combination of IL-6, IL-10 and salivary cortisol (r = 0.492). The lack of correlation between intestinal permeability and gastrointestinal symptoms could be due to minor symptoms experienced in lab settings compared to real-life competitions. The correlation between L/R ratio and uric acid might imply a barrier-protective effect of uric acid, and inflammatory processes due to strenuous exercise seem to play an important role regarding physical exhaustion.
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| 8. |
- Yildiz, Ahmet Bahadir, 1989-, et al.
(författare)
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Design, synthesis, structure, and stability of novel multi-principal element (Ti,Zr,Hf,W)C ceramic with a miscibility gap
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Multi-principal element carbide systems offer unprecedented mechanical properties such as high hardness and fracture toughness in as-sintered state. This makes them potential candidates for structural elements in high-temperature applications. Here we design a novel multi-principal element carbide system (Ti,Zr,Hf,W)C with a miscibility gap using computational tools and report on the formation of a single-phase (Ti,Zr,Hf,W)C after spark plasma sintering. The (Ti,Zr,Hf,W)C shows high nanohardness (33.1 GPa) and fracture toughness (5 MPa/m2) resulting from the high bonding energy and solid solution effects. Furthermore, aging studies at 1350 °C show that the single-phase is quite stable even though this temperature is within the predicted miscibility gap of the system. Detailed electron microscopy characterization shows that phase separation has initiated with minor decomposition after 100 h of aging at 1350 °C by forming rock-salt (Ti,W)C- and (Zr,Hf)C-rich phases as well as hexagonal WC precipitates. We show that the atoms distribute homogeneously through the single-phase (Ti,Zr,Hf,W)C grains in the as-sintered sample; and the (Ti,W)C- and (Zr,Hf)C-rich phases form a lamellar structure upon aging. The interlamellar spacing is considerably coarser than what has been previously found for the binary (Ti,Zr)C system. The decomposition kinetics, on the other hand, is sluggish due to the reduced driving force for phase decomposition.
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