| 1. |
- Andersen, Henrik L., et al.
(författare)
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Local and long-range atomic/magnetic structure of non-stoichiometric spinel iron oxide nanocrystallites
- 2021
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Ingår i: IUCrJ. - 2052-2525. ; 8, s. 33-45
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Tidskriftsartikel (refereegranskat)abstract
- Spinel iron oxide nanoparticles of different mean sizes in the range 10-25 nm have been prepared by surfactant-free up-scalable near- and super-critical hydrothermal synthesis pathways and characterized using a wide range of advanced structural characterization methods to provide a highly detailed structural description. The atomic structure is examined by combined Rietveld analysis of synchrotron powder X-ray diffraction (PXRD) data and time-of-flight neutron powder-diffraction (NPD) data. The local atomic ordering is further analysed by pair distribution function (PDF) analysis of both X-ray and neutron total-scattering data. It is observed that a non-stoichiometric structural model based on a tetragonal γ-Fe2O3 phase with vacancy ordering in the structure (space group P43212) yields the best fit to the PXRD and total-scattering data. Detailed peak-profile analysis reveals a shorter coherence length for the superstructure, which may be attributed to the vacancy-ordered domains being smaller than the size of the crystallites and/or the presence of anti-phase boundaries, faulting or other disorder effects. The intermediate stoichiometry between that of γ-Fe2O3 and Fe3O4 is confirmed by refinement of the Fe/O stoichiometry in the scattering data and quantitative analysis of Mössbauer spectra. The structural characterization is complemented by nano/micro-structural analysis using transmission electron microscopy (TEM), elemental mapping using scanning TEM, energy-dispersive X-ray spectroscopy and the measurement of macroscopic magnetic properties using vibrating sample magnetometry. Notably, no evidence is found of a Fe3O4/γ-Fe2O3 core-shell nanostructure being present, which had previously been suggested for non-stoichiometric spinel iron oxide nanoparticles. Finally, the study is concluded using the magnetic PDF (mPDF) method to model the neutron total-scattering data and determine the local magnetic ordering and magnetic domain sizes in the iron oxide nanoparticles. The mPDF data analysis reveals ferrimagnetic collinear ordering of the spins in the structure and the magnetic domain sizes to be ∼60-70% of the total nanoparticle sizes. The present study is the first in which mPDF analysis has been applied to magnetic nanoparticles, establishing a successful precedent for future studies of magnetic nanoparticles using this technique.
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| 2. |
- Bech, Sara, et al.
(författare)
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Amyloid-related biomarkers and axonal damage proteins in parkinsonian syndromes.
- 2012
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Ingår i: Parkinsonism & related disorders. - : Elsevier BV. - 1873-5126 .- 1353-8020. ; 18:1, s. 69-72
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Tidskriftsartikel (refereegranskat)abstract
- Clinical differentiation between parkinsonian syndromes (PS) remains a challenge despite well-established clinical diagnostic criteria. Specific diagnostic biomarkers have yet to be identified, though in recent years, studies have been published on the aid of certain brain related proteins (BRP) in the diagnosing of PS. We investigated the levels of the light subunit of neurofilament triplet protein (NF-L), total tau and phosphorylated tau, amyloid-β(1-42), and the soluble α- and β-cleaved fragments of amyloid precursor proteins in a cohort of patients with various PS.
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| 3. |
- Kilpeläinen, Tuomas O, et al.
(författare)
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Genome-wide meta-analysis uncovers novel loci influencing circulating leptin levels
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Leptin is an adipocyte-secreted hormone, the circulating levels of which correlate closely with overall adiposity. Although rare mutations in the leptin (LEP) gene are well known to cause leptin deficiency and severe obesity, no common loci regulating circulating leptin levels have been uncovered. Therefore, we performed a genome-wide association study (GWAS) of circulating leptin levels from 32,161 individuals and followed up loci reaching P<10(-6) in 19,979 additional individuals. We identify five loci robustly associated (P<5 × 10(-8)) with leptin levels in/near LEP, SLC32A1, GCKR, CCNL1 and FTO. Although the association of the FTO obesity locus with leptin levels is abolished by adjustment for BMI, associations of the four other loci are independent of adiposity. The GCKR locus was found associated with multiple metabolic traits in previous GWAS and the CCNL1 locus with birth weight. Knockdown experiments in mouse adipose tissue explants show convincing evidence for adipogenin, a regulator of adipocyte differentiation, as the novel causal gene in the SLC32A1 locus influencing leptin levels. Our findings provide novel insights into the regulation of leptin production by adipose tissue and open new avenues for examining the influence of variation in leptin levels on adiposity and metabolic health.
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| 4. |
- Fenton, Thomas M., et al.
(författare)
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Immune Profiling of Human Gut-Associated Lymphoid Tissue Identifies a Role for Isolated Lymphoid Follicles in Priming of Region-Specific Immunity
- 2020
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Ingår i: Immunity. - : Elsevier BV. - 1074-7613. ; 52:3, s. 557-570
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Tidskriftsartikel (refereegranskat)abstract
- The intestine contains some of the most diverse and complex immune compartments in the body. Here we describe a method for isolating human gut-associated lymphoid tissues (GALTs) that allows unprecedented profiling of the adaptive immune system in submucosal and mucosal isolated lymphoid follicles (SM-ILFs and M-ILFs, respectively) as well as in GALT-free intestinal lamina propria (LP). SM-ILF and M-ILF showed distinct patterns of distribution along the length of the intestine, were linked to the systemic circulation through MAdCAM-1+ high endothelial venules and efferent lymphatics, and had immune profiles consistent with immune-inductive sites. IgA sequencing analysis indicated that human ILFs are sites where intestinal adaptive immune responses are initiated in an anatomically restricted manner. Our findings position ILFs as key inductive hubs for regional immunity in the human intestine, and the methods presented will allow future assessment of these compartments in health and disease.
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| 5. |
- Jørgensen, Peter B., et al.
(författare)
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Identification, isolation and analysis of human gut-associated lymphoid tissues
- 2021
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Ingår i: Nature Protocols. - : Springer Science and Business Media LLC. - 1754-2189 .- 1750-2799. ; 16:4, s. 2051-2067
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Tidskriftsartikel (refereegranskat)abstract
- Gut-associated lymphoid tissues (GALTs) comprise key intestinal immune inductive sites, including the Peyer’s patches of the small intestine and different types of isolated lymphoid follicle (ILF) found along the length of the gut. Our understanding of human GALT is limited due to a lack of protocols for their isolation. Here we describe a technique that, uniquely among intestinal cell isolation protocols, allows identification and isolation of all human GALT, as well as GALT-free intestinal lamina propria (LP). The technique involves the mechanical separation of intestinal mucosa from the submucosa, allowing the identification and isolation of submucosal ILF (SM-ILF), LP-embedded mucosal ILF (M-ILF) and LP free of contaminating lymphoid tissue. Individual SM-ILF, M-ILF and Peyer’s patch follicles can be subsequently digested for downstream cellular and molecular characterization. The technique, which takes 4–10 h, will be useful for researchers interested in intestinal immune development and function in health and disease.
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| 6. |
- Sigurdsson, Halldor Armann, et al.
(författare)
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Subject Float, Low Subject Trapping, and Case in Icelandic
- 2019
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Ingår i: The sign of the V : Papers in honour of Sten Vikner - Papers in honour of Sten Vikner. - : Aahus University Library. - 9788791134050 - 9788775074617 ; , s. 591-618
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Bokkapitel (refereegranskat)abstract
- This article describes and discusses two peculiar sets of (in)defi nitenessfacts applying to subjects in Icelandic, here referred to as Subject Floatand Low Subject Trapping. Indefi nite subjects (commonly quantifi ed) inpresentational sentences and related clause types may either occupy thecomplement position within the predicate phrase or “fl oat” into variouspositions in the middle fi eld. This is Subject Float, yielding variation suchas “There would (many farmers) then (many farmers) probably (manyfarmers) be (?*many farmers) elected (many farmers)”. Conversely, andunexpectedly, defi nite NP subjects of some adjectival and verbal predicatesmust stay in the complement position. This is Low Subject Trapping,yielding orders such as “there is cold radiator-the” and “there cooledradiator-the”. It is shown that the licensing of subject NPs in the variouspositions in Subject Float and in the complement position in Low SubjectTrapping is unrelated to specifi c grammatical cases, thus refuting the widelyadopted case approach to NP licensing. Although Icelandic case markinghas been widely discussed, Subject Float and Low Subject Trapping havenot previously received a detailed scrutiny; these phenomena provideadditional and partly new knockout arguments against the case approach toNP licensing and NP movement. While high NP raising to subject (Spec,IP)is unaffected by case, it seems to involve both Person and Topic matching.
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