| 1. |
- Abdo, A. A., et al.
(författare)
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The on-orbit calibration of the Fermi Large Area Telescope
- 2009
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 32:3-4, s. 193-219
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Tidskriftsartikel (refereegranskat)abstract
- The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.
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| 2. |
- Aspholm-Hurtig, Marina, et al.
(författare)
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Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin.
- 2004
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 305:5683, s. 519-22
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Tidskriftsartikel (refereegranskat)abstract
- Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.
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| 3. |
- Bodin, Per, et al.
(författare)
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Guidance, navigation, and control experiments on the PRISMA in-orbit test bed
- 2007
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Ingår i: 58th International Astronautical Congress, IAC-07-C1. - 9781605601502 ; , s. 4461-4470
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Konferensbidrag (refereegranskat)abstract
- PRISMA will demonstrate Guidance, Navigation and Control strategies for advanced autonomous formation flying and rendezvous. The Swedish Space Corporation (SSC) is the prime contractor for the project which is funded by the Swedish National Space Board (SNSB). The project is further supported by the German Aerospace Center (DLR), the Technical University of Denmark (DTU), and the French Space Agency (CNES). PRISMA consists of two spacecraft: MAIN and TARGET. The MAIN satellite is 3-axis stabilized and has full 3D delta-V maneuverability that is independent of the spacecraft's attitude. The TARGET satellite has a simplified, yet 3-axis stabilizing, magnetic attitude control system and no orbit maneuver capability. This paper presents the PRISMA Guidance, Navigation, and Control (GNC) subsystem. The paper gives a mission summary and an overview of the GNC subsystem with its hardware and software configuration. It also explains how the orbit control functions contain advanced fuel optimal Model Predictive Control (MPC). It is shown how the GNC software is developed using model based automatic coding technology implemented with Matlab/Simulink. The paper then summarizes the different GNC experiments to be performed by SSC. Finally, an overview of the test approach for the subsystem is given.
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| 4. |
- Leifsdottir, Kristin, et al.
(författare)
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The cerebrospinal fluid proteome of preterm infants predicts neurodevelopmental outcome
- 2022
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Ingår i: Frontiers in Pediatrics. - : Frontiers Media SA. - 2296-2360. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundSurvival rate increases for preterm infants, but long-term neurodevelopmental outcome predictors are lacking. Our primary aim was to determine whether a specific proteomic profile in cerebrospinal fluid (CSF) of preterm infants differs from that of term infants and to identify novel biomarkers of neurodevelopmental outcome in preterm infants. MethodsTwenty-seven preterm infants with median gestational age 27 w + 4 d and ten full-term infants were enrolled prospectively. Protein profiling of CSF were performed utilizing an antibody suspension bead array. The relative levels of 178 unique brain derived proteins and inflammatory mediators, selected from the Human Protein Atlas, were measured. ResultsThe CSF protein profile of preterm infants differed from that of term infants. Increased levels of brain specific proteins that are associated with neurodevelopment and neuroinflammatory pathways made up a distinct protein profile in the preterm infants. The most significant differences were seen in proteins involved in neurodevelopmental regulation and synaptic plasticity, as well as components of the innate immune system. Several proteins correlated with favorable outcome in preterm infants at 18-24 months corrected age. Among the proteins that provided strong predictors of outcome were vascular endothelial growth factor C, Neurocan core protein and seizure protein 6, all highly important in normal brain development. ConclusionOur data suggest a vulnerability of the preterm brain to postnatal events and that alterations in protein levels may contribute to unfavorable neurodevelopmental outcome.
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| 5. |
- Olsson, Lisa M., 1984, et al.
(författare)
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Dynamics of the normal gut microbiota: A longitudinal one-year population study in Sweden
- 2022
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Ingår i: Cell Host and Microbe. - : Elsevier BV. - 1931-3128 .- 1934-6069. ; 30:5
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Tidskriftsartikel (refereegranskat)abstract
- Temporal dynamics of the gut microbiota potentially limit the identification of microbial features associated with health status. Here, we used whole-genome metagenomic and 16S rRNA gene sequencing to characterize the intra- and inter-individual variations of gut microbiota composition and functional potential of a disease-free Swedish population (n = 75) over one year. We found that 23% of the total compositional variance was explained by intra-individual variation. The degree of intra-individual compositional variability was negatively associated with the abundance of Faecalibacterium prausnitzii (a butyrate producer) and two Bifidobacterium species. By contrast, the abundance of facultative anaerobes and aerotolerant bacteria such as Escherichia coli and Lactobacillus acidophilus varied extensively, independent of compositional stability. The contribution of intra-individual variance to the total variance was greater for functional pathways than for microbial species. Thus, reliable quantification of microbial features requires repeated samples to address the issue of intra-individual variations of the gut microbiota.
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| 6. |
- Roswall, Josefine, et al.
(författare)
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Developmental trajectory of the healthy human gut microbiota during the first 5 years of life
- 2021
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Ingår i: Cell Host & Microbe. - : Elsevier BV. - 1931-3128 .- 1934-6069. ; 29:5
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Tidskriftsartikel (refereegranskat)abstract
- The gut is inhabited by a densely populated ecosystem, the gut microbiota, that is established at birth. However, the succession by which different bacteria are incorporated into the gut microbiota is still relatively unknown. Here, we analyze the microbiota from 471 Swedish children followed from birth to 5 years of age, collecting samples after 4 and 12 months and at 3 and 5 years of age as well as from their mothers at birth using 16S rRNA gene profiling. We also compare their microbiota to an adult Swedish population. Genera follow 4 different colonization patterns during establishment where Methanobrevibacter and Christensenellaceae colonize late and do not reached adult levels at 5 years. These late colonizers correlate with increased alpha diversity in both children and adults. By following the children through age-specific community types, we observe that children have individual dynamics in the gut microbiota development trajectory.
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| 7. |
- Söder, Lennart, 1956-, et al.
(författare)
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Är kärnkraften nödvändig för en fossilfri, svensk, elproduktion?
- 2020
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Rapport (populärvet., debatt m.m.)abstract
- Efter flera år av stöd har sol- och vind-el blivit ekonomiskt konkurrenskraftiga och börjat konkurrera ut stora termiska anläggningar för elproduktion. Det stängs nu kol- och kärnkraftverk i flera länder i världen och förespråkare för dessa teknologier hävdar, på olika sätt, att marknaden styr fel och att dessa kraftverk ”behövs” av olika skäl.I denna rapport har vi undersökt om det finns någon grund för ett sådant ”behov” av kärnkraftverk i Sverige som motiverar att det sker nyinvesteringar trots att konkurrensen på marknaden håller på att slå ut dem.Syftet med denna rapport är inte att fastslå om man bör ha ett framtida elsystem med eller utan kärnkraft, utan att analysera grunderna, dvs kunskapsläget, för påståendet att det är nödvändigt att ha kärnkraft. Alla diskussioner om framtiden är osäkra, så vi gör heller inte anspråk på att förutse hur framtiden kommer se ut. Upplägget är att gå igenom olika frågeställningar, och koppla dessa till frågan om huruvida kärnkraften är nödvändig för framtiden, så som framförts med exempelvis följande argument:a) Kärnkraft behövs av ekonomiska skälb) Kärnkraft behövs för att vi inte ska vara importberoendec) Kärnkraft behövs eftersom det finns kapacitetsbrist i t ex Malmö och Stockholmd) Kärnkraft behövs för att klara elektrifieringen av transporterna och industrine) Kärnkraft behövs för att klara klimatmåletf) Kärnkraft behövs för att vi ska få el alla timmar, dvs klara leveranssäkerheteng) Kärnkraften behövs för att klara frekvensstabilitetenh) Kärnkraft behövs för stödtjänster till elsystemetI avsnitt 2-7 finns en genomgång av dagsläget. I avsnitt 8 finns en mer detaljerad genomgång av listan a)-h) ovan. Mer tekniska detaljer om systembalansering och effektbalansberäkningar finns i Bilaga A-C.Den slutsats vi drar är att kärnkraften inte är nödvändig för att vi ska kunna få ett stabilt, säkert och fossilfritt elsystem i Sverige i framtiden. Ett elsystem med stor mängd sol- och vindkraft ser dock annorlunda ut än ett med stor mängd kärnkraft. Frågan är då om detta system blir dyrare. Ingen vet vad olika kraftslag kommer att kosta år 2045, men under senare år har det skett en kraftig minskning av kostnaderna för sol- och vindkraft. Samtidigt har kärnkraftens kostnader istället ökat kraftigt. Den är nu betydligt dyrare än ny vindkraft.
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| 8. |
- Tarnawski, Laura, et al.
(författare)
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Cholinergic regulation of vascular endothelial function by human ChAT + T cells
- 2023
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 120:14
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Tidskriftsartikel (refereegranskat)abstract
- Endothelial dysfunction and impaired vasodilation are linked with adverse cardiovascular events. T lymphocytes expressing choline acetyltransferase (ChAT), the enzyme catalyzing biosynthesis of the vasorelaxant acetylcholine (ACh), regulate vasodilation and are integral to the cholinergic antiinflammatory pathway in an inflammatory reflex in mice. Here, we found that human T cell ChAT mRNA expression was induced by T cell activation involving the PI3K signaling cascade. Mechanistically, we identified that ChAT mRNA expression was induced following the attenuation of RE-1 Silencing Transcription factor REST-mediated methylation of the ChAT promoter, and that ChAT mRNA expression levels were up-regulated by GATA3 in human T cells. In functional experiments, T cell-derived ACh increased endothelial nitric oxide-synthase activity, promoted vasorelaxation, and reduced vascular endothelial activation and promoted barrier integrity by a cholinergic mechanism. Further, we observed that survival in a cohort of patients with severe circulatory failure correlated with their relative frequency of ChAT+CD4+ T cells in blood. These findings on ChAT+ human T cells provide a mechanism for cholinergic immune regulation of vascular endothelial function in human inflammation.
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| 9. |
- Vitos, Levente, et al.
(författare)
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Mechanical properties and magnetism: stainless steel alloys from first-principles theory
- 2011
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Ingår i: 2010 MRS Fall Meeting. - : Springer Science and Business Media LLC. - 9781618395092 ; , s. 68-79
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Konferensbidrag (refereegranskat)abstract
- Stainless steels are among the most important engineering materials, finding their principal scope in industry, specifically in cutlery, food production, storage, architecture, medical equipment, etc. Austenitic stainless steels form the largest sub-category of stainless steels having as the main building blocks the paramagnetic substitutional disordered Fe-Cr-Ni-based alloys. Because of that, austenitic steels represent the primary choice for non-magnetic engineering materials. The presence of the chemical and magnetic disorder hindered any previous attempt to calculate the fundamental electronic, structural and mechanical properties of austenitic stainless steels from first-principles theories. Our ability to reach an ab initio atomistic level approach in this exciting field has become possible by the Exact Muffin-Tin Orbitals (EMTO) method. This method, in combination with the coherent potential approximation, has proved an accurate tool in the description of the concentrated random alloys. Using the EMTO method, we presented an insight to the electronic and magnetic structure, and micromechanical properties of austenitic stainless steel alloys. In the present contribution, we will discuss the role of magnetism on the stacking fault energies and elastic properties of paramagnetic Fe-based alloys.
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| 10. |
- Vitos, Levente, et al.
(författare)
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Stainless steel alloys from first-principles theory
- 2011
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Ingår i: 7th European Stainless Steel Conference. - : Associazione Italiana di Metallurgia. - 9788885298842
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Konferensbidrag (refereegranskat)abstract
- Gaining an accurate description of materials obviously requires the most advanced atomic-scale techniques from both experimental and theoretical areas. In spite of the vast number of available techniques, however, the experimental study of the atomic-scale properties and phenomena even in simple solids is rather difficult. In steels the challenges become more complex due to the interplay between the structural, chemical and magnetic effects. On the other hand, advanced computational methods based on density functional theory ensure a proper platform for studying the fundamental properties of steel materials from first-principles. Our group at the Royal Institute of Technology in Stockholm has an international position in developing and applying computational codes for such applications. Using our ab initio tools, we have presented an insight to the electronic and magnetic structure, and micromechanical properties of austenitic stainless steel alloys. In the present contribution, we review the most important developments within the ab initio quantum-mechanics-aided steel design with special emphasis on the role of magnetism on the fundamental properties of alloy steels.
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