ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Telomere dysfunction induces metabolic and mitochondrial compromise (2011)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2011-02-11
    Description: Telomere dysfunction activates p53-mediated cellular growth arrest, senescence and apoptosis to drive progressive atrophy and functional decline in high-turnover tissues. The broader adverse impact of telomere dysfunction across many tissues including more quiescent systems prompted transcriptomic network analyses to identify common mechanisms operative in haematopoietic stem cells, heart and liver. These unbiased studies revealed profound repression of peroxisome proliferator-activated receptor gamma, coactivator 1 alpha and beta (PGC-1alpha and PGC-1beta, also known as Ppargc1a and Ppargc1b, respectively) and the downstream network in mice null for either telomerase reverse transcriptase (Tert) or telomerase RNA component (Terc) genes. Consistent with PGCs as master regulators of mitochondrial physiology and metabolism, telomere dysfunction is associated with impaired mitochondrial biogenesis and function, decreased gluconeogenesis, cardiomyopathy, and increased reactive oxygen species. In the setting of telomere dysfunction, enforced Tert or PGC-1alpha expression or germline deletion of p53 (also known as Trp53) substantially restores PGC network expression, mitochondrial respiration, cardiac function and gluconeogenesis. We demonstrate that telomere dysfunction activates p53 which in turn binds and represses PGC-1alpha and PGC-1beta promoters, thereby forging a direct link between telomere and mitochondrial biology. We propose that this telomere-p53-PGC axis contributes to organ and metabolic failure and to diminishing organismal fitness in the setting of telomere dysfunction.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3741661/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3741661/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sahin, Ergun -- Colla, Simona -- Liesa, Marc -- Moslehi, Javid -- Muller, Florian L -- Guo, Mira -- Cooper, Marcus -- Kotton, Darrell -- Fabian, Attila J -- Walkey, Carl -- Maser, Richard S -- Tonon, Giovanni -- Foerster, Friedrich -- Xiong, Robert -- Wang, Y Alan -- Shukla, Sachet A -- Jaskelioff, Mariela -- Martin, Eric S -- Heffernan, Timothy P -- Protopopov, Alexei -- Ivanova, Elena -- Mahoney, John E -- Kost-Alimova, Maria -- Perry, Samuel R -- Bronson, Roderick -- Liao, Ronglih -- Mulligan, Richard -- Shirihai, Orian S -- Chin, Lynda -- DePinho, Ronald A -- P30 DK046200/DK/NIDDK NIH HHS/ -- P30DK079638/DK/NIDDK NIH HHS/ -- R01 CA084628/CA/NCI NIH HHS/ -- R01 DK035914/DK/NIDDK NIH HHS/ -- R01 DK056690/DK/NIDDK NIH HHS/ -- R01 DK063356/DK/NIDDK NIH HHS/ -- R01 DK089185/DK/NIDDK NIH HHS/ -- U24 DK-59635/DK/NIDDK NIH HHS/ -- England -- Nature. 2011 Feb 17;470(7334):359-65. doi: 10.1038/nature09787. Epub 2011 Feb 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Belfer Institute for Applied Cancer Science, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21307849" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/biosynthesis ; Aging/metabolism/pathology ; Animals ; Cardiomyopathies/chemically induced/metabolism/pathology/physiopathology ; Cell Proliferation ; DNA, Mitochondrial/analysis ; Doxorubicin/toxicity ; Gluconeogenesis ; Hematopoietic Stem Cells/metabolism/pathology ; Liver/cytology/metabolism ; Mice ; Mitochondria/*metabolism/*pathology ; Myocardium/cytology/metabolism ; RNA/genetics ; Reactive Oxygen Species/metabolism ; Telomerase/deficiency/genetics ; Telomere/enzymology/genetics/*metabolism/*pathology ; Transcription Factors/antagonists & inhibitors/metabolism ; Tumor Suppressor Protein p53/deficiency/genetics/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Complete correction of murine Artemis immunodeficiency by lentiviral vector-mediated gene transfer (2006)
    National Academy of Sciences
    Details
    Publication Date: 2006-10-24
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    High radio-frequency properties and variability of brightest cluster galaxies (2015)
    Oxford University Press
    Details
    Publication Date: 2015-08-27
    Description: We consider the high radio-frequency (15–353 GHz) properties and variability of 35 brightest cluster galaxies (BCGs). These are the most core-dominated sources drawn from a parent sample of more than 700 X-ray selected clusters, thus allowing us to relate our results to the general population. We find that ≥6.0 per cent of our parent sample (≥15.1 per cent if only cool-core clusters are considered) contain a radio source at 150 GHz of at least 3 mJy (1 x 10 23 W Hz –1 at our median redshift of z   0.13). Furthermore, ≥3.4 per cent of the BCGs in our parent sample contain a peaked component (Gigahertz Peaked Spectrum, GPS) in their spectra that peaks above 2 GHz, increasing to ≥8.5 per cent if only cool-core clusters are considered. We see little evidence for strong variability at 15 GHz on short (week–month) time-scales although we see variations greater than 20 per cent at 150 GHz over six-month time frames for 4 of the 23 sources with multi-epoch observations. Much more prevalent is long-term (year–decade time-scale) variability, with average annual amplitude variations greater than 1 per cent at 15 GHz being commonplace. There is a weak trend towards higher variability as the peak of the GPS-like component occurs at higher frequency. We demonstrate the complexity that is seen in the radio spectra of BCGs and discuss the potentially significant implications of these high-peaking components for Sunyaev–Zel‘dovich cluster searches.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Diagnosing the accretion flow in ultraluminous X-ray sources using soft X-ray atomic features (2015)
    Oxford University Press
    Details
    Publication Date: 2015-10-19
    Description: The lack of unambiguous detections of atomic features in the X-ray spectra of ultraluminous X-ray sources (ULXs) has proven a hindrance in diagnosing the nature of the accretion flow. The possible association of spectral residuals at soft energies with atomic features seen in absorption and/or emission and potentially broadened by velocity dispersion could therefore hold the key to understanding much about these enigmatic sources. Here we show for the first time that such residuals are seen in several sources and appear extremely similar in shape, implying a common origin. Via simple arguments we assert that emission from extreme colliding winds, absorption in a shell of material associated with the ULX nebula and thermal plasma emission associated with star formation are all highly unlikely to provide an origin. Whilst CCD spectra lack the energy resolution necessary to directly determine the nature of the features (i.e. formed of a complex of narrow lines or intrinsically broad lines), studying the evolution of the residuals with underlying spectral shape allows for an important, indirect test for their origin. The ULX NGC 1313 X-1 provides the best opportunity to perform such a test due to the dynamic range in spectral hardness provided by archival observations. We show through highly simplified spectral modelling that the strength of the features (in either absorption or emission) appears to anticorrelate with spectral hardness, which would rule out an origin via reflection of a primary continuum and instead supports a picture of atomic transitions in a wind or nearby material associated with such an outflow.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    A deep Chandra observation of the hot gaseous halo around a rare, extremely massive and relativistic jet launching spiral galaxy (2015)
    Oxford University Press
    Details
    Publication Date: 2015-04-10
    Description: We present a deep Chandra observation of the extremely massive spiral galaxy 2MASX J23453268–0449256, the first X-ray observation of this very rare system which features the largest known relativistic jets from a spiral galaxy. We detect extended X-ray emission from the hot halo surrounding the galaxy, reaching out to 80 kpc in radius. The hot halo is elongated along the plane of the spiral galaxy, and one possibility is that the powerful relativistic jets have disrupted the hot halo gas located perpendicular to the disc. Our calculations indicate that it is energetically feasible that the AGN feedback in this system could have uplifted or completely expelled a significant fraction of the gas in the 20–80-kpc radial range. We also detect extended emission which appears to be associated with the inner and outer southern radio lobes, and is possibly the result of inverse Compton emission. Using the observed X-ray and radio luminosity of the central AGN, the Fundamental Plane of Gultekin et al. predicts a black hole mass of 5 10 8 M , with a range of 1 10 8 –3 10 9 M when the scatter in the Fundamental Plane relation is taken into account. This is consistent with the possibility that an exceptionally massive (〉10 9 M ) black hole lies at the centre of this galaxy, as suggested by the M BH – scaling relation, but a tighter constraint cannot be made.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Collisional excitation of [C II], [O I] and CO in massive galaxies (2015)
    Oxford University Press
    Details
    Publication Date: 2015-11-28
    Description: Many massive galaxies at the centres of relaxed galaxy clusters and groups have vast reservoirs of warm (~10 000 K) and cold (100 K) gas. In many such low-redshift systems this gas is lifted into the hot interstellar medium in filamentary structures, which are long lived and are typically not forming stars. Two important questions are how far do these reservoirs cool and if cold gas is abundant what is the cause of the low star formation efficiency? Heating and excitation of the filaments from collisions and mixing of hot particles in the surrounding X-ray gas describes well the optical and near infrared line ratios observed in the filaments. In this paper we examine the theoretical properties of dense, cold clouds emitting in the far infrared and sub-millimetre through the bright lines of [C  ii ] 157 μm , [O  i ] 63 μm and CO, exposed to such energetic ionizing particles. We find that optical depth effects and thermal pressure support alone cannot account for the line ratios; however, a very modest additional pressure support can fit the observed [O  i ] 63 μm/[C  ii ] 157 μm line ratios by decreasing the density of the gas. This may also help stabilize the filaments against collapse leading to the low rates of star formation. We make predictions for the line ratios expected from cold gas under these conditions and present diagnostic diagrams for comparison with further observations. We provide our code as an Appendix.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Discovery of an ~2-h high-frequency X-ray QPO and iron K{alpha} reverberation in the active galaxy MS 2254.9-3712 (2015)
    Oxford University Press
    Details
    Publication Date: 2015-03-20
    Description: We report the discovery of an ~1.5 10 –4 Hz (~2 h) X-ray quasi-periodic oscillation (QPO) in the active galaxy MS 2254.9–3712, using an ~70 ks XMM–Newton observation. The QPO is significantly detected (~3.3) in the 1.2–5.0 keV band only, connecting its origin with the primary X-ray power-law continuum. We detect a highly coherent soft lag between the 0.3–0.7 keV and 1.2–5.0 keV energy bands at the QPO frequency and at a frequency band in a 3:2 ratio, strongly suggesting the presence of a QPO harmonic. An iron Kα reverberation lag is found at the harmonic frequency, indicating the reflecting material subtends some angle to the primary continuum, which is modulated by the QPO mechanism. Frequency-resolved spectroscopy reveals the QPO and harmonic to have a hard energy dependence. These properties of the QPO variability, together with the current black hole mass estimate, M BH ~ 4 x 10 6 M , are consistent with the QPO originating from the same process as the high-frequency QPO phenomenon observed in black hole X-ray binaries. Principle component analysis reveals the spectral variability in MS 2254.9–3712 is similar to that of the active galaxy RE J1034+396, a source which also displays an X-ray QPO. This suggests a distinct spectral-variability pattern for accreting black holes when in a state where QPOs are present.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Iron K and Compton hump reverberation in SWIFT J2127.4+5654 and NGC 1365 revealed by NuSTAR and XMM-Newton (2014)
    Oxford University Press
    Details
    Publication Date: 2014-11-14
    Description: In the past five years, a flurry of X-ray reverberation lag measurements of accreting supermassive black holes have been made using the XMM–Newton telescope in the 0.3–10 keV energy range. In this work, we use the NuSTAR ( Nuclear Spectroscopic Telescope Array ) telescope to extend the lag analysis up to higher energies for two Seyfert galaxies, SWIFT J2127.4+5654 and NGC 1365. X-ray reverberation lags are due to the light travel time delays between the direct continuum emission and the reprocessed emission from the inner radii of an ionized accretion disc. XMM–Newton has been particularly adept at measuring the lag associated with the broad Fe K emission line, where the gravitationally redshifted wing of the line is observed to respond before the line centroid at 6.4 keV, produced at larger radii. Now, we use NuSTAR to probe the lag at higher energies, where the spectrum shows clear evidence for Compton reflection, known as the Compton ‘hump’. The XMM–Newton data show Fe K lags in both SWIFT J2127.4+5654 and NGC 1365. The NuSTAR data provide independent confirmation of these Fe K lags, and also show evidence for the corresponding Compton hump lags, especially in SWIFT J2127.4+5654. These broad-band lag measurements confirm that the Compton hump and Fe K lag are produced at small radii. At low frequencies in NGC 1365, where the spectrum shows evidence for eclipsing clouds in the line of sight, we find a clear negative (not positive) lag from 2 to 10 keV, which can be understood as the decrease in column density from a neutral eclipsing cloud moving out of our line of sight during the observation.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Modelling the extreme X-ray spectrum of IRAS 13224-3809 (2014)
    Oxford University Press
    Details
    Publication Date: 2014-11-15
    Description: The extreme narrow-line Seyfert 1 galaxy IRAS 13224–3809 shows significant variability, frequency-dependent time lags, and strong Fe K line and Fe L features in the long 2011 XMM–Newton observation. In this work, we study the spectral properties of IRAS 13224–3809 in detail, and carry out a series of analyses to probe the nature of the source, focusing in particular on the spectral variability exhibited. The reflection grating spectrometer spectrum shows no obvious signatures of absorption by partially ionized material (‘warm’ absorbers). We fit the 0.3–10.0 keV spectra with a model that includes relativistic reflection from the inner accretion disc, a standard power-law active galactic nucleus continuum, and a low-temperature (~0.1 keV) blackbody, which may originate in the accretion disc, either as direct or reprocessed thermal emission. We find that the reflection model explains the time-averaged spectrum well, and we also undertake flux-resolved and time-resolved spectral analyses, which provide evidence of gravitational light-bending effects. Additionally, the temperature and flux of the blackbody component are found to follow the L T 4 relation expected for simple thermal blackbody emission from a constant emitting area, indicating a physical origin for this component.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    The distribution of dark and luminous matter in the unique galaxy cluster merger Abell 2146 (2016)
    Oxford University Press
    Details
    Publication Date: 2016-04-23
    Description: Abell 2146 ( z  = 0.232) consists of two galaxy clusters undergoing a major merger. The system was discovered in previous work, where two large shock fronts were detected using the Chandra X-ray Observatory , consistent with a merger close to the plane of the sky, caught soon after first core passage. A weak gravitational lensing analysis of the total gravitating mass in the system, using the distorted shapes of distant galaxies seen with Advanced Camera for Surveys - Wide Field Channel on Hubble Space Telescope , is presented. The highest peak in the reconstruction of the projected mass is centred on the brightest cluster galaxy (BCG) in Abell 2146-A. The mass associated with Abell 2146-B is more extended. Bootstrapped noise mass reconstructions show the mass peak in Abell 2146-A to be consistently centred on the BCG. Previous work showed that BCG-A appears to lag behind an X-ray cool core; although the peak of the mass reconstruction is centred on the BCG, it is also consistent with the X-ray peak given the resolution of the weak lensing mass map. The best-fitting mass model with two components centred on the BCGs yields M 200 = 1.1 $^{+0.3}_{-0.4}$ x 10 15 and 3 $^{+1}_{-2}$ x 10 14  M for Abell 2146-A and Abell 2146-B, respectively, assuming a mass concentration parameter of c = 3.5 for each cluster. From the weak lensing analysis, Abell 2146-A is the primary halo component, and the origin of the apparent discrepancy with the X-ray analysis where Abell 2146-B is the primary halo is being assessed using simulations of the merger.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...