| 1. |
- Dahl, F, et al.
(författare)
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Imaging single DNA molecules for high precision NIPT
- 2018
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1, s. 4549-
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Tidskriftsartikel (refereegranskat)abstract
- Cell-free DNA analysis is becoming adopted for first line aneuploidy screening, however for most healthcare programs, cost and workflow complexity is limiting adoption of the test. We report a novel cost effective method, the Vanadis NIPT assay, designed for high precision digitally-enabled measurement of chromosomal aneuploidies in maternal plasma. Reducing NIPT assay complexity is achieved by using novel molecular probe technology that specifically label target chromosomes combined with a new readout format using a nanofilter to enrich single molecules for imaging and counting without DNA amplification, microarrays or sequencing. The primary objective of this study was to assess the Vanadis NIPT assay with respect to analytical precision and clinical feasibility. Analysis of reference DNA samples indicate that samples which are challenging to analyze with low fetal-fraction can be readily detected with a limit of detection determined at <2% fetal-fraction. In total of 286 clinical samples were analysed and 30 out of 30 pregnancies affected by trisomy 21 were classified correctly. This method has the potential to make cost effective NIPT more widely available with more women benefiting from superior detection and false positive rates.
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| 3. |
- Schoos, A.-M. M., et al.
(författare)
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Early indoor aeroallergen exposure is not associated with development of sensitization or allergic rhinitis in high-risk children
- 2016
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Ingår i: Allergy. European Journal of Allergy and Clinical Immunology. - : Wiley. - 0105-4538 .- 1398-9995. ; 71:5, s. 684-691
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: Allergen exposure is associated with the development of allergic sensitization in childhood as reflected by global variations in sensitization patterns. However, there is little evidence to support a direct association.Objectives: To investigate the association between perinatal aeroallergen exposure and sensitization and rhinitis to such allergens later in childhood.Methods: Allergic sensitization to cat, dog, and house dust mites was diagnosed longitudinally using skin prick tests and specific IgE measurements at 1/2, 11/2, 4, 6, and 13 years in 399 children from the Copenhagen Prospective Study on Asthma in Childhood(2000) birth cohort. Rhinitis was diagnosed at 7 and 13 years. Allergen exposure was defined as dog or cat in the home during the 3rd trimester of pregnancy or the first year of life and as allergen levels of dog, cat, and house dust mite in bed dust samples at 1 year. Associations between exposure and outcomes were analyzed by logistic regression and stratified for eczema status and test method (skin prick test and specific IgE).Results: We found no association between dog or cat exposure in perinatal life and sensitization or rhinitis during childhood. Similarly, there was no association between levels of allergens in bed dust samples and sensitization or rhinitis during childhood.Conclusion: Perinatal indoor aeroallergen exposure does not seem to affect development of allergic sensitization or rhinitis during childhood questioning the relevance of allergen avoidance as a preventive measure. Other factors such as timing of allergen exposure or other environmental adjuvants may contribute in a more complex pathway to sensitization.
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| 4. |
- Boschi, Samuele, et al.
(författare)
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Popigai impact ejecta layer and extraterrestrial spinels recovered in a new Italian location—The Monte Vaccaro section (Marche Apennines, Italy)
- 2019
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Ingår i: 250 Million Years of Earth History in Central Italy: Celebrating 25 Years of the Geological Observatory of Coldigioco. - : Geological Society of America. - 0072-1077. ; 542, s. 355-367
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The Popigai (100 km in diameter) and the Chesapeake Bay (40–85 km diameter) impact structures formed within ~10–20 k.y. in the late Eocene during a 2 m.y. period with enhanced flux of 3He-rich interplanetary dust to Earth. Ejecta from the Siberian Popigai impact structure have been found in late Eocene marine sediments at numerous deep-sea drilling sites around the globe and also in a few marine sections outcropped on land, like the Massignano section near Ancona in Italy. In the Massignano section, the Popigai layer is associated with an iridium anomaly, shocked quartz, and abundant clinopyroxene-bearing (cpx) spherules, altered to smectite and flattened to “pancake spherules.” The ejecta are also associated with a significant enrichment of H-chondritic chromite grains (>63 µm), likely representing unmelted fragments of the impactor. The Massignano section also contains abundant terrestrial chrome-spinel grains, making reconstructions of the micrometeorite flux very difficult. We therefore searched for an alternative section that would be more useful for these types of studies. Here, we report the discovery of such a section, and also the first discovery of the Popigai ejecta in another locality in Italy, the Monte Vaccaro section, 90 km west of Ancona. The Monte Vaccaro section biostratigraphy was established based on calcareous nannoplankton, which allowed the identification of a sequence of distinct bioevents showing a good correlation with the Massignano section. In both the Monte Vaccaro and Massignano sections, the Popigai ejecta layer occurs in calcareous nannofossil zone CNE 19. The ejecta layer in the Monte Vaccaro section contains shocked quartz, abundant pancake spherules, and an iridium anomaly of 700 ppt, which is three times higher than the peak Ir measured in the ejecta layer at Massignano. In a 105-kg-size sample from just above the ejecta layer at Monte Vaccaro, we also found an enrichment of H-chondritic chromite grains. Because of its condensed nature and low content of terrestrial spinel grains, the Monte Vaccaro section holds great potential for reconstructions of the micrometeorite flux to Earth during the late Eocene using spinels.
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| 7. |
- Limburg, K. E., et al.
(författare)
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Insights from two-dimensional mapping of otolith chemistry
- 2017
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 90:2, s. 480-491
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Tidskriftsartikel (refereegranskat)abstract
- Non-destructive microbeam-based methods were used for 2-D mapping of trace elements to gain a greater appreciation of otolith composition and spatial configuration. Based on studies of a wide variety of fish taxa, this approach more fully captures the nature of otolith chemical heterogeneity. Such variations may be due to a number of factors, including differences in crystallization, genetics, growth or even sample preparation or contamination. Examples presented here highlight research conducted at the Lund Ion Beam Analysis Facility (LIBAF) and at the Cornell High-Energy Synchrotron Source (CHESS).
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| 8. |
- Pallon, J., et al.
(författare)
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Ion beam evaluation of silicon carbide membrane structures intended for particle detectors
- 2016
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 371, s. 132-136
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Tidskriftsartikel (refereegranskat)abstract
- Thin ion transmission detectors can be used as a part of a telescope detector for mass and energy identification but also as a pre-cell detector in a microbeam system for studies of biological effects from single ion hits on individual living cells. We investigated a structure of graphene on silicon carbide (SiC) with the purpose to explore a thin transmission detector with a very low noise level and having mechanical strength to act as a vacuum window. In order to reach very deep cavities in the SiC wafers for the preparation of the membrane in the detector, we have studied the Inductive Coupled Plasma technique to etch deep circular cavities in 325 μm prototype samples. By a special high temperature process the outermost layers of the etched SiC wafers were converted into a highly conductive graphitic layer. The produced cavities were characterized by electron microscopy, optical microscopy and proton energy loss measurements. The average membrane thickness was found to be less than 40 μm, however, with a slightly curved profile. Small spots representing much thinner membrane were also observed and might have an origin in crystal defects or impurities. Proton energy loss measurement (also called Scanning Transmission Ion Microscopy, STIM) is a well suited technique for this thickness range. This work presents the first steps of fabricating a membrane structure of SiC and graphene which may be an attractive approach as a detector due to the combined properties of SiC and graphene in a monolithic materials structure.
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