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- Wetzell, V, et al.
(author)
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Velocity dispersions of clusters in the Dark Energy Survey Y3 redMaPPer catalogue
- 2022
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In: Monthly notices of the Royal Astronomical Society. - : Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 514:4, s. 4696-4717
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Journal article (peer-reviewed)abstract
- We measure the velocity dispersions of clusters of galaxies selected by the red-sequence Matched-filter Probabilistic Percolation (redMaPPer) algorithm in the first three years of data from the Dark Energy Survey (DES), allowing us to probe cluster selection and richness estimation, λ, in light of cluster dynamics. Our sample consists of 126 clusters with sufficient spectroscopy for individual velocity dispersion estimates. We examine the correlations between cluster velocity dispersion, richness, X-ray temperature, and luminosity, as well as central galaxy velocity offsets. The velocity dispersion–richness relation exhibits a bimodal distribution. The majority of clusters follow scaling relations between velocity dispersion, richness, and X-ray properties similar to those found for previous samples; however, there is a significant population of clusters with velocity dispersions that are high for their richness. These clusters account for roughly 22 per cent of the λ < 70 systems in our sample, but more than half (55 per cent) of λ < 70 clusters at z > 0.5. A couple of these systems are hot and X-ray bright as expected for massive clusters with richnesses that appear to have been underestimated, but most appear to have high velocity dispersions for their X-ray properties likely due to line-of-sight structure. These results suggest that projection effects contribute significantly to redMaPPer selection, particularly at higher redshifts and lower richnesses. The redMaPPer determined richnesses for the velocity dispersion outliers are consistent with their X-ray properties, but several are X-ray undetected and deeper data are needed to understand their nature.
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- Feng, Shaohong, et al.
(author)
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Dense sampling of bird diversity increases power of comparative genomics
- 2020
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 587:7833
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Journal article (peer-reviewed)abstract
- Whole-genome sequencing projects are increasingly populating the tree of life and characterizing biodiversity(1-4). Sparse taxon sampling has previously been proposed to confound phylogenetic inference(5), and captures only a fraction of the genomic diversity. Here we report a substantial step towards the dense representation of avian phylogenetic and molecular diversity, by analysing 363 genomes from 92.4% of bird families-including 267 newly sequenced genomes produced for phase II of the Bird 10,000 Genomes (B10K) Project. We use this comparative genome dataset in combination with a pipeline that leverages a reference-free whole-genome alignment to identify orthologous regions in greater numbers than has previously been possible and to recognize genomic novelties in particular bird lineages. The densely sampled alignment provides a single-base-pair map of selection, has more than doubled the fraction of bases that are confidently predicted to be under conservation and reveals extensive patterns of weak selection in predominantly non-coding DNA. Our results demonstrate that increasing the diversity of genomes used in comparative studies can reveal more shared and lineage-specific variation, and improve the investigation of genomic characteristics. We anticipate that this genomic resource will offer new perspectives on evolutionary processes in cross-species comparative analyses and assist in efforts to conserve species. A dataset of the genomes of 363 species from the Bird 10,000 Genomes Project shows increased power to detect shared and lineage-specific variation, demonstrating the importance of phylogenetically diverse taxon sampling in whole-genome sequencing.
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- DaCosta, R. S., et al.
(author)
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Autofluorescence characterisation of isolated whole crypts and primary cultured human epithelial cells from normal, hyperplastic, and adenomatous colonic mucosa
- 2005
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In: Journal of Clinical Pathology. - : BMJ. - 0021-9746 .- 1472-4146. ; 58:7, s. 766-774
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Journal article (peer-reviewed)abstract
- Background/Aims: In vivo autofluorescence endoscopic imaging and spectroscopy have been used to detect and differentiate benign ( hyperplastic) and preneoplastic ( adenomatous) colonic lesions. This fluorescence is composed of contributions from the epithelium, lamina propria, and submucosa. Because epithelial autofluorescence in normal and diseased tissues is poorly understood, this was the focus of the present study. Methods: Whole colonic crypts were isolated, and short term primary cultures of epithelial cells were established from biopsies of normal, hyperplastic, and adenomatous colon. Autofluorescence ( 488 nm excitation) was examined by confocal fluorescence microscopy. Fluorescently labelled organelle probes and transmission electron microscopy were used to identify subcellular sources of fluorescence. Results: Mitochondria and lysosomes were identified as the main intracellular fluorescent components in all cell types. Normal and hyperplastic epithelial cells were weakly autofluorescent and had similar numbers of mitochondria and lysosomes, whereas adenomatous ( dysplastic) epithelial cells showed much higher autofluorescence, and numerous highly autofluorescent lysosomal ( lipofuscin) granules. Conclusions: Short term primary cell cultures from endoscopic biopsies provide a novel model to understand differences in colonic tissue autofluorescence at the glandular ( crypt) and cellular levels. The differences between normal, hyperplastic, and adenomatous epithelial cells are attributed in part to differences in the intrinsic numbers of mitochondria and lysosomes. This suggests that the detection of colonic epithelial fluorescence alone, if possible, may be sufficient to differentiate benign ( hyperplastic) from preneoplastic and neoplastic ( adenomatous) colonic intramucosal lesions during in vivo fluorescence endoscopy. Furthermore, highly orange/red autofluorescent intracellular granules found only in dysplastic epithelial cells may serve as a potential biomarker.
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- DaCosta, R. S., et al.
(author)
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Molecular fluorescence excitation-emission matrices relevant to tissue spectroscopy
- 2003
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In: Photochemistry and Photobiology. - 0031-8655 .- 1751-1097. ; 78:4, s. 384-392
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Journal article (peer-reviewed)abstract
- In vivo and ex vivo studies of fluorescence from endogenous and exogenous molecules in tissues and cells are common for applications such as detection or characterization of early disease. A systematic determination of the excitation-emission matrices (EEM) of known and putative endogenous fluorophores and a number of exogenous fluorescent photodynamic therapy drugs has been performed in solution. The excitation wavelength range was 250-520 nm, with fluorescence emission spectra collected in the range 260-750 nm. In addition, EEM of intact normal and adenomatous human colon tissues are presented as an example of the relationship to the EEM of constituent fluorophores and illustrating the effects of tissue chromophore absorption. As a means to make this large quantity of spectral data generally available, an interactive database has been developed. This currently includes EEM and also absorption spectra of 35 different endogenous and exogenous fluorophores and chromophores and six photosensitizing agents. It is intended to maintain and extend this database in the public domain, accessible through the Photochemistry and Photobiology website (http://www.aspjournal.com/).
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- Emmelkamp, J., et al.
(author)
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The potential of autofluorescence for the detection of single living cells for label-free cell sorting in microfluidic systems
- 2004
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In: Electrophoresis. - : Wiley. - 0173-0835 .- 1522-2683. ; 25:21-22, s. 3740-3745
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Journal article (peer-reviewed)abstract
- A novel method for studying unlabeled living mammalian cells based on their autofluorescence (AF) signal in a prototype microfluidic device is presented. When combined, cellular AF detection and microfluidic devices have the potential to facilitate high-throughput analysis of different cell populations. To demonstrate this, unlabeled cultured cells in microfluidic devices were excited with a 488 nm excitation light and the AF emission (> 505 nm) was detected using a confocal fluorescence microscope (CFM). For example, a simple microfluidic three-port glass microstructure was used together with conventional electroosmotic flow (EOF) to switch the direction of the fluid flow. As a means to test the potential of AF-based cell sorting in this microfluidic device, granulocytes were successfully differentiated from human red blood cells (RBCs) based on differences in AF This study demonstrated the use of a simple microfabricated device to perform high-throughput live cell detection and differentiation without the need for cell-specific fluorescent labeling dyes and thereby reducing the sample preparation time. Hence, the combined use of microfluidic devices and cell AF may have many applications in single-cell analysis.
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