433 research outputs found
Distant galaxy clusters in the COSMOS field found by HIROCS
We present the first high-redshift galaxy cluster candidate sample from the
HIROCS survey found in the COSMOS field. It results from a combination of
public COSMOS with proprietary H-band data on a 0.66 square degree part of the
COSMOS field and comprises 12 candidates in the redshift range 1.23 < z < 1.55.
We find an increasing fraction of blue cluster members with increasing
redshift. Many of the blue and even some of the reddest member galaxies exhibit
disturbed morphologies as well as signs of interaction.Comment: 5 pages, 5 figures, in print format, accepted for publication by A&A
Letter
Gene transfer into hepatocytes using asialoglycoprotein receptor mediated endocytosis of DNA complexed with an artificial tetra-antennary galactose ligand
We have constructed an artificial ligand for the hepatocyte-specific asialoglycoprotein receptor for the purpose of generating a synthetic delivery system for DNA. This ligand has a tetra-antennary structure, containing four terminal galactose residues on a branched carrier peptide. The carbohydrate residues of this glycopeptide were introduced by reductive coupling of lactose to the alpha- and epsilon-amino groups of the two N-terminal lysines on the carrier peptide. The C-terminus of the peptide, containing a cysteine separated from the branched N-terminus by a 10 amino acid spacer sequence, was used for conjugation to 3-(2-pyridyldithio)propionate-modified polylysine via disulfide bond formation. Complexes containing plasmid DNA bound to these galactose-polylysine conjugates have been used for asialoglycoprotein receptor-mediated transfer of a luciferase gene into human (HepG2) and murine (BNL CL.2) hepatocyte cell lines. Gene transfer was strongly promoted when amphipathic peptides with pH-controlled membrane-disruption activity, derived from the N-terminal sequence of influenza virus hemagglutinin HA-2, were also present in these DNA complexes. Thus, we have essentially borrowed the small functional domains of two large proteins, asialoglycoprotein and hemagglutinin, and assembled them into a supramolecular complex to generate an efficient gene-transfer system
PSMB2 and RPL32 are suitable denominators to normalize gene expression profiles in bronchoalveolar cells
<p>Abstract</p> <p>Background</p> <p>For accuracy of quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), normalisation with suitable reference genes is required. To date, no reference genes have been validated for expression studies of bronchoalveolar (BAL) cells. The aims of this study were to identify gene(s) with stable mRNA expression in BAL cells irrespective of gender, smoking, BAL cellular composition, lung pathology, treatment; and to assess the influence of reference genes on target gene expression data.</p> <p>Results</p> <p>The mRNA expression of ten housekeeping genes (ACTB, ARF1, CANX, G6PD, GAPDH, GPS1, GNB2L1, PSMB2, PSMD2, RPL32) was investigated by qRT-PCR in BAL cells from 71 subjects across a spectrum of lung diseases. The analyses were validated in an independent BAL cohort from 63 sarcoidosis patients and 17 control subjects. A second derivative method was used to calculate expression values (CTt); an equivalence test, applets BestKeeper, geNorm and NormFinder were applied to investigate gene expression stability. Of the investigated genes, PSMB2 (CTt ± SD, 23.66 ± 0.86) and RPL32 (18.65 ± 0.92) were the most stable; both were constantly expressed in BAL samples from parallel investigated cohorts irrespective of evaluated variables. Finally, to demonstrate effect of traditional (ACTB/GAPDH) and novel (PSMB2/RPL32) reference genes as denominators, expression of two cytokines known associated with sarcoidosis was investigated in sarcoid BAL cells. While normalization with PSMB2/RPL32 resulted in elevated IFNG mRNA expression (<it>p </it>= 0.004); no change was observed using GAPDH/ACTB (<it>p </it>> 0.05). CCL2 mRNA up-regulation was observed only when PSMB2/RPL32 were used as denominators (<it>p </it>< 0.03).</p> <p>Conclusion</p> <p>PSMB2 and RPL32 are, therefore, suitable reference genes to normalize qRT-PCR in BAL cells in sarcoidosis, and other interstitial lung disease.</p
Enhancing reuse of data and biological material in medical research : from FAIR to FAIR-Health
The known challenge of underutilization of data and biological material from biorepositories as potential resources
formedical research has been the focus of discussion for over a decade. Recently developed guidelines for improved
data availability and reusability—entitled FAIR Principles (Findability, Accessibility, Interoperability, and
Reusability)—are likely to address only parts of the problem. In this article,we argue that biologicalmaterial and data
should be viewed as a unified resource. This approach would facilitate access to complete provenance information,
which is a prerequisite for reproducibility and meaningful integration of the data. A unified view also allows for
optimization of long-term storage strategies, as demonstrated in the case of biobanks.Wepropose an extension of the
FAIR Principles to include the following additional components: (1) quality aspects related to research reproducibility
and meaningful reuse of the data, (2) incentives to stimulate effective enrichment of data sets and biological
material collections and its reuse on all levels, and (3) privacy-respecting approaches for working with the human
material and data. These FAIR-Health principles should then be applied to both the biological material and data. We
also propose the development of common guidelines for cloud architectures, due to the unprecedented growth of
volume and breadth of medical data generation, as well as the associated need to process the data efficiently.peer-reviewe
Spectral Energy Distributions of Type 1 AGN in the COSMOS Survey I - The XMM-COSMOS Sample
The "Cosmic Evolution Survey" (COSMOS) enables the study of the Spectral
Energy Distributions (SEDs) of Active Galactic Nuclei (AGN) because of the deep
coverage and rich sampling of frequencies from X-ray to radio. Here we present
a SED catalog of 413 X-ray (\xmm) selected type 1 (emission line FWHM km
s) AGN with Magellan, SDSS or VLT spectrum. The SEDs are corrected for
the Galactic extinction, for broad emission line contributions, constrained
variability, and for host galaxy contribution. We present the mean SED and the
dispersion SEDs after the above corrections in the rest frame 1.4 GHz to 40
keV, and show examples of the variety of SEDs encountered. In the near-infrared
to optical (rest frame -- 4000\AA), the photometry is complete for
the whole sample and the mean SED is derived from detections only. Reddening
and host galaxy contamination could account for a large fraction of the
observed SED variety. The SEDs are all available on-line.Comment: 22 pages, 22 figures, ApJ accepted, scheduled to be published October
20th, 2012, v75
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