Signatures in a Giant Radio Galaxy of a Cosmological Shock Wave at Intersecting Filaments of Galaxies

Sensitive images of low-level, Mpc-sized radio cocoons offer new opportunities to probe large scale intergalactic gas flows outside clusters of galaxies. New radio images of high surface brightness sensitivity at strategically chosen wavelengths of the giant radio galaxy NGC 315 (Mack et al. 1997,1998) reveal significant asymmetries and particularities in the morphology, radio spectrum and polarization of the ejected radio plasma. We argue that the combination of these signatures provides a sensitive probe of an environmental shock wave. Analysis of optical redshifts in NGC 315 vicinity confirms its location to be near, or at a site of large-scale flow collisions in the 100 Mpc sized Pisces-Perseus Supercluster region. NGC 315 resides at the intersection of several galaxy filaments, and its radio plasma serves there as a `weather station' (Burns 1998) probing the flow of the elusive and previously invisible IGM gas. If our interpretation is correct, this is the first indication for a shock wave in flows caused by the cosmological large scale structure formation, which is located in a filament of galaxies. The possibility that the putative shock wave is a source of gamma-rays and ultra high energy cosmic rays is briefly discussed.Comment: accepted by Astrophysical Journal Letters, 4 pages, 3 figures (incl. 2 color), uses emulateapj5.sty (included), aastex.sty (included) and psfig.st

The Ionized Gas Kinematics of the LMC-Type Galaxy NGC 1427A in the Fornax Cluster

NGC 1427A is a LMC-like irregular galaxy in the Fornax cluster with an extended pattern of strong star formation around one of its edges, which is probably due to some kind of interaction with the cluster environment. We present H-alpha velocities within NGC 1427A, obtained through long-slit spectroscopy at seven different positions, chosen to fall on the brightest HII regions of the galaxy. Due to its location very near the center of the cluster this object is an excellent candidate to study the effects that the cluster environment has on gas-rich galaxies embedded in it. The rotation of NGC 1427A is modeled in two different ways. The global ionized gas kinematics is reasonably well described by solid-body rotation, although on small scales it shows a chaotic behaviour. In this simple model, the collision with a smaller member of the cluster as being responsible for the peculiar morphology of NGC 1427A is very unlikely, since the only candidate intruder falls smoothly into the general velocity pattern of the main galaxy. In a more elaborate model, for which we obtain a better solution, this object does not lie in the same plane of NGC 1427A, in which case we identify it as a satellite bound to the galaxy. These results are discussed in the context of a normal irregular versus one interacting with some external agent. Based on several arguments and quantitative estimates, we argue that the passage through the hot intracluster gas of the Fornax cluster is a very likely scenario to explain the morphological properties of NGC 1427A.Comment: 31 pages, LaTeX2e, uses aas2pp4.sty and psfig.sty, including 7 Postscript figures; accepted for publication in ApJ, Vol. 530, February 200

Towards an Understanding of the Globular Cluster Over--abundance around the Central Giant Elliptical NGC 1399

We investigate the kinematics of a combined sample of 74 globular clusters around NGC 1399. Their high velocity dispersion, increasing with radius, supports their association with the gravitational potential of the galaxy cluster rather than with that of NGC 1399 itself. We find no evidence for rotation in the full sample, although some indication for rotation in the outer regions. The data do not allow us to detect differences between the kinematics of the blue and red sub-populations of globular clusters. A comparison between the globular cluster systems of NGC 1399 and those of NGC 1404 and NGC 1380 indicates that the globular clusters in all three galaxies are likely to have formed via similar mechanisms and at similar epochs. The only property which distinguishes the NGC 1399 globular cluster system from these others is that it is ten times more abundant. We summarize the evidence for associating these excess globulars with the galaxy cluster rather than with NGC 1399 itself, and suggest that the over-abundance can be explained by tidal stripping, at an early epoch, of neighboring galaxies and subsequent accumulation of globulars in the gravitational potential of the galaxy cluster.Comment: AJ accepted (March issue), 27 pages (6 figures included), AAS style, two columns. Also available at http://www.eso.org/~mkissle

A genomic biomarker signature can predict skin sensitizers using a cell-based in vitro alternative to animal tests

<p>Abstract</p> <p>Background</p> <p>Allergic contact dermatitis is an inflammatory skin disease that affects a significant proportion of the population. This disease is caused by an adverse immune response towards chemical haptens, and leads to a substantial economic burden for society. Current test of sensitizing chemicals rely on animal experimentation. New legislations on the registration and use of chemicals within pharmaceutical and cosmetic industries have stimulated significant research efforts to develop alternative, human cell-based assays for the prediction of sensitization. The aim is to replace animal experiments with in vitro tests displaying a higher predictive power.</p> <p>Results</p> <p>We have developed a novel cell-based assay for the prediction of sensitizing chemicals. By analyzing the transcriptome of the human cell line MUTZ-3 after 24 h stimulation, using 20 different sensitizing chemicals, 20 non-sensitizing chemicals and vehicle controls, we have identified a biomarker signature of 200 genes with potent discriminatory ability. Using a Support Vector Machine for supervised classification, the prediction performance of the assay revealed an area under the ROC curve of 0.98. In addition, categorizing the chemicals according to the LLNA assay, this gene signature could also predict sensitizing potency. The identified markers are involved in biological pathways with immunological relevant functions, which can shed light on the process of human sensitization.</p> <p>Conclusions</p> <p>A gene signature predicting sensitization, using a human cell line in vitro, has been identified. This simple and robust cell-based assay has the potential to completely replace or drastically reduce the utilization of test systems based on experimental animals. Being based on human biology, the assay is proposed to be more accurate for predicting sensitization in humans, than the traditional animal-based tests.</p

Molecular Signatures of Prostate Stem Cells Reveal Novel Signaling Pathways and Provide Insights into Prostate Cancer

BACKGROUND:The global gene expression profiles of adult and fetal murine prostate stem cells were determined to define common and unique regulators whose misexpression might play a role in the development of prostate cancer. METHODOLOGY/PRINCIPAL FINDINGS:A distinctive core of transcriptional regulators common to both fetal and adult primitive prostate cells was identified as well as molecules that are exclusive to each population. Elements common to fetal and adult prostate stem cells include expression profiles of Wnt, Shh and other pathways identified in stem cells of other organs, signatures of the aryl-hydrocarbon receptor, and up-regulation of components of the aldehyde dehydrogenase/retinoic acid receptor axis. There is also a significant lipid metabolism signature, marked by overexpression of lipid metabolizing enzymes and the presence of the binding motif for Srebp1. The fetal stem cell population, characterized by more rapid proliferation and self-renewal, expresses regulators of the cell cycle, such as E2f, Nfy, Tead2 and Ap2, at elevated levels, while adult stem cells show a signature in which TGF-beta has a prominent role. Finally, comparison of the signatures of primitive prostate cells with previously described profiles of human prostate tumors identified stem cell molecules and pathways with deregulated expression in prostate tumors including chromatin modifiers and the oncogene, Erg. CONCLUSIONS/SIGNIFICANCE:Our data indicate that adult prostate stem or progenitor cells may acquire characteristics of self-renewing primitive fetal prostate cells during oncogenesis and suggest that aberrant activation of components of prostate stem cell pathways may contribute to the development of prostate tumors

Bestimmung von Benzol im Grundwasser

Bei der Untersuchung von Grundwasserproben gleichen Ursprungs aus Beobachtungsbrunnen im Rahmen anstehender Altlastensanierungen wurden fuer Benzol von mehreren Laboratorien sehr stark voneinander abweichende Werte gemessen. Da bei Altlastensanierungen sehr niedrige Sanierungsrichtwerte gefordert werden, ist eine exakte Analytik unerlaesslich. Die in diesem Projekt durchgefuehrten Ringversuche haben zu folgenden Ergebnissen gefuehrt: - Die Probenahme ist in DIN 38402, Teil 13, hinreichend beschrieben. - Die Analyse von BTX im Grundwasser ist in DIN 38407, Teil 9, umfassend dargelegt. - Entscheidend ist die Lagerfaehigkeit der Grundwasserproben. Analysen sollten innerhalb von 48 h, besser 24 h nach Probenahme durchgefuehrt werden, andernfalls sind die Proben zur Unterbindung der mikrobiellen Taetigkeit zu stabilisieren. - Die Ergebnisse zeigen im Bereich der unteren Bestimmungsgrenze 5 #mu#g/l erhebliche Streuungen. Es ist daher in Frage zu stellen, ob die in diesem Bereich festgelegten Sanierungsrichtwerte sicher und zuverlaessig gemessen werden koennen. (orig.)Groundwater samples of the same origin (planned groundwater treatment) have been analysed by several laboratories. Concerning the compound benzene big differences occured in the concentrations measured. As very low concentration levels are demanded for remediation activities an exact analytical procedure is necessary. Round robin tests performed during this project showed to the following results: - Sampling is described sufficiently in DIN 38402, part 13. -Analysis of BTX aromates is described in detail in DIN 38407, part 9. - Problems occur during storage of groundwater samples. Analysis should be performed within 48 hours, or even better within 24 hours after sampling. Otherwise samples should be stabilized for suppression of microbial activity. - Near the lower limit of application for benzene (5 #mu#g/l) results show considerable deviations. Therefore it is doubtful that limit values can be monitored accurately if set as this range of concentration for remediation purposes. (orig.)SIGLEAvailable from TIB Hannover: RN 4117(497) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman