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| 2. |
- Jakosky, B. M., et al.
(författare)
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MAVEN observations of the response of Mars to an interplanetary coronal mass ejection
- 2015
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 350:6261
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Tidskriftsartikel (refereegranskat)abstract
- Coupling between the lower and upper atmosphere, combined with loss of gas from the upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern Mars. To help understand ongoing ion loss to space, the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft made comprehensive measurements of the Mars upper atmosphere, ionosphere, and interactions with the Sun and solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes in the bow shock and magnetosheath, formation of widespread diffuse aurora, and enhancement of pick-up ions. Observations and models both show an enhancement in escape rate of ions to space during the event. Ion loss during solar events early in Mars history may have been a major contributor to the long-term evolution of the Mars atmosphere.
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| 3. |
- Chaillou, Thomas, 1985-, et al.
(författare)
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Identification of a conserved set of upregulated genes in mouse skeletal muscle hypertrophy and regrowth
- 2015
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Ingår i: Journal of applied physiology. - Bethesda, USA : American Physiological Society. - 8750-7587 .- 1522-1601. ; 118, s. 86-97
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to compare the gene expression profile of mouse skeletal muscle undergoing two forms of growth (hypertrophy and regrowth) with the goal of identifying a conserved set of differentially expressed genes. Expression profiling by microarray was performed on the plantaris muscle subjected to 1, 3, 5, 7, 10, and 14 days of hypertrophy or regrowth following 2 wk of hind-limb suspension. We identified 97 differentially expressed genes (≥2-fold increase or ≥50% decrease compared with control muscle) that were conserved during the two forms of muscle growth. The vast majority (∼90%) of the differentially expressed genes was upregulated and occurred at a single time point (64 out of 86 genes), which most often was on the first day of the time course. Microarray analysis from the conserved upregulated genes showed a set of genes related to contractile apparatus and stress response at day 1, including three genes involved in mechanotransduction and four genes encoding heat shock proteins. Our analysis further identified three cell cycle-related genes at day and several genes associated with extracellular matrix (ECM) at both days 3 and 10. In conclusion, we have identified a core set of genes commonly upregulated in two forms of muscle growth that could play a role in the maintenance of sarcomere stability, ECM remodeling, cell proliferation, fast-to-slow fiber type transition, and the regulation of skeletal muscle growth. These findings suggest conserved regulatory mechanisms involved in the adaptation of skeletal muscle to increased mechanical loading.
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| 4. |
- Kirby, T.J., et al.
(författare)
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Blunted hypertrophic response in aged skeletal muscle is associated with decreased ribosome biogenesis
- 2015
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Ingår i: Journal of applied physiology. - Bethesda, USA : American Physiological Society. - 8750-7587 .- 1522-1601. ; 119:4, s. 321-327
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Tidskriftsartikel (refereegranskat)abstract
- The ability of skeletal muscle to hypertrophy in response to a growth stimulus is known to be compromised in older individuals. We hypothesized that a change in the expression of protein-encoding genes in response to a hypertrophic stimulus contributes to the blunted hypertrophy observed with aging. To test this hypothesis, we determined gene expression by microarray analysis of plantaris muscle from 5- and 25-mo-old mice subjected to 1, 3, 5, 7, 10, and 14 days of synergist ablation to induce hypertrophy. Overall, 1,607 genes were identified as being differentially expressed across the time course between young and old groups; however, the difference in gene expression was modest, with cluster analysis showing a similar pattern of expression between the two groups. Despite ribosome protein gene expression being higher in the aged group, ribosome biogenesis was significantly blunted in the skeletal muscle of aged mice compared with mice young in response to the hypertrophic stimulus (50% vs. 2.5-fold, respectively). The failure to upregulate pre-47S ribosomal RNA (rRNA) expression in muscle undergoing hypertrophy of old mice indicated that rDNA transcription by RNA polymerase I was impaired. Contrary to our hypothesis, the findings of the study suggest that impaired ribosome biogenesis was a primary factor underlying the blunted hypertrophic response observed in skeletal muscle of old mice rather than dramatic differences in the expression of protein-encoding genes. The diminished increase in total RNA, pre-47S rRNA, and 28S rRNA expression in aged muscle suggest that the primary dysfunction in ribosome biogenesis occurs at the level of rRNA transcription and processing.
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| 7. |
- Strandberg, B., et al.
(författare)
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Near-threshold π-photoproduction on the deuteron
- 2020
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Ingår i: Physical Review C. - 2469-9985. ; 101:3
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Tidskriftsartikel (refereegranskat)abstract
- The first experimental investigation of the near-threshold cross section for incoherent π-photoproduction on the deuteron γd→π-pp is presented. The experimental technique involved detection of the ≈131 MeV γ ray resulting from the radiative capture of photoproduced π-in the target. The total cross section was measured using an unpolarized tagged-photon beam, a liquid-deuterium target, and three very large NaI(Tl) spectrometers. The data are compared to theoretical models that give insight into the elementary reaction γn→π-p and pion-nucleon and nucleon-nucleon final-state interactions.
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| 8. |
- Mansour, A., et al.
(författare)
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Diarrhea Burden Due to Natural Infection with Enterotoxigenic Escherichia coli in a Birth Cohort in a Rural Egyptian Community
- 2014
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 52:7, s. 2595-2603
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Tidskriftsartikel (refereegranskat)abstract
- Enterotoxigenic Escherichia coli (ETEC) is commonly associated with diarrhea in Egyptian children. Children less than 3 years old in Abu Homos, Egypt, had approximately five diarrheal episodes per child every year, and at least one of these episodes was due to ETEC. The epidemiology of ETEC diarrhea among children living in a rural Egyptian community was further evaluated in this study. Between January 2004 and April 2007, 348 neonates were enrolled and followed for 2 years. Children were visited twice weekly, and a stool sample was obtained every 2 weeks regardless of symptomatology. A stool sample was obtained whenever a child had diarrhea. From the routine stool culture, five E. coli-like colonies were selected and screened for heat-labile and heat-stable toxins by GM1 enzyme-linked immunosorbent assay (ELISA) and further typed for colonization factor antigens by dot blot assay. Incidence of ETEC infection was estimated among children with diarrhea (symptomatic) and without diarrhea (asymptomatic). Incidence of diarrhea and ETEC-associated diarrhea was 7.8 and 1.48 per child-year, respectively. High risk of repeated ETEC diarrhea was associated with being over 6 months of age, warm season, male gender, and crowded sleeping conditions. Exclusive breast-feeding was protective for repeated ETEC infection. ETEC-associated diarrhea remains common among children living in the Nile Delta. The protective role of breast-feeding demonstrates the importance of promoting exclusive breast-feeding during, at least, the first 6 months of life.
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| 9. |
- Rich, Rebecca L., et al.
(författare)
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A global benchmark study using affinity-based biosensors
- 2009
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Ingår i: Analytical Biochemistry. - : Elsevier BV. - 0003-2697 .- 1096-0309. ; 386:2, s. 194-216
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Tidskriftsartikel (refereegranskat)abstract
- To explore the variability in biosensor studies, 150 participants from 20 countries were given the same protein samples and asked to determine kinetic rate constants for the interaction. We chose a protein system that was amenable to analysis using different biosensor platforms as well as by users of different expertise levels. The two proteins (a 50-kDa Fab and a 60-kDa glutathione S-transferase [GST] antigen) form a relatively high-affinity complex, so participants needed to optimize several experimental parameters, including ligand immobilization and regeneration conditions as well as analyte concentrations and injection/dissociation times. Although most participants collected binding responses that could be fit to yield kinetic parameters, the quality of a few data sets could have been improved by optimizing the assay design. Once these outliers were removed, the average reported affinity across the remaining panel of participants was 620 pM with a standard deviation of 980 pM. These results demonstrate that when this biosensor assay was designed and executed appropriately, the reported rate constants were consistent, and independent of which protein was immobilized and which biosensor was used.
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| 10. |
- Strandberg, B., et al.
(författare)
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Compton scattering from the deuteron above pion-production threshold
- 2018
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Ingår i: Physical Review C. - 2469-9985. ; 98:1
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Tidskriftsartikel (refereegranskat)abstract
- The electromagnetic polarizabilities of the nucleon are fundamental nucleon-structure observables that characterize its response to external electromagnetic fields. The neutron polarizabilities can be accessed from Compton-scattering data on light nuclear targets. Recent measurements of the differential cross section for Compton scattering on the deuteron below the pion-production threshold have decreased the uncertainties in the neutron polarizabilities, yet the proton polarizabilities remain known substantially more accurately. As the sensitivity of the cross section to the polarizabilities increases with incident photon energy, measurements above the pion threshold may offer a way for an improved determination of the neutron polarizabilities. In this Rapid Communiciation, the first measurement of the cross section for coherent Compton scattering on the deuteron above the pion-production threshold is presented.
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