629 research outputs found

    Fever, Chills, Hepatomegaly And Debility

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    Stellar Dynamics and the implications on the merger evolution in NGC6240

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    We report near-infrared integral field spectroscopy of the luminous merging galaxy NGC 6240. Stellar velocities show that the two K-band peaks separated by 1.6arcsec are the central parts of inclined, rotating disk galaxies with equal mass bulges. The dynamical masses of the nuclei are much larger than the stellar mass derived from the K-band light, implying that the progenitor galaxies were galaxies with massive bulges. The K-band light is dominated by red supergiants formed in the two nuclei in starbursts, triggered ~2x10^7 years ago, possibly by the most recent perigalactic approach. Strong feedback effects of a superwind and supernovae are responsible for a short duration burst (~5x10^6 years) which is already decaying. The two galaxies form a prograde-retrograde rotating system and from the stellar velocity field it seems that one of the two interacting galaxies is subject to a prograde encounter. Between the stellar nuclei is a prominent peak of molecular gas (H_2, CO). The stellar velocity dispersion peaks there indicating that the gas has formed a local, self-gravitating concentration decoupled from the stellar gravitational potential. NGC 6240 has previously been reported to fit the paradigm of an elliptical galaxy formed through the merger of two galaxies. This was based on the near-infrared light distribution which follows a r^1/4-law. Our data cast strong doubt on this conclusion: the system is by far not relaxed, rotation plays an important role, as does self-gravitating gas, and the near-infrared light is dominated by young stars.Comment: 34 pages, 11 figures, using AASTEX 5.0rc3.1, paper submitted to the Astrophysical Journal, revised versio

    Teaching tolerance

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    Babies born with Pompe disease require life-long treatment with enzyme-replacement therapy (ERT). Despite the human origin of the therapy, recombinant human lysosomal acid α glucosidase (GAA, rhGAA), ERT unfortunately leads to the development of high titers of anti-rhGAA antibody, decreased effectiveness of ERT, and a fatal outcome for a significant number of children who have Pompe disease. The severity of disease, anti-drug antibody (ADA) development, and the consequences thereof are directly related to the degree of the enzyme deficiency. Babies born with a complete deficiency GAA are said to have cross-reactive immunologic material (CRIM)–negative Pompe disease and are highly likely to develop GAA ADA. Less frequently, GAA ADA develop in CRIM-positive individuals. Currently, GAA-ADA sero-positive babies are treated with a combination of immunosuppressive drugs to induce immunological tolerance to ERT, but the long-term effect of these regimens is unknown. Alternative approaches that might redirect the immune response toward antigen-specific tolerance without immunosuppressive agents are needed. Methods leading to the induction of antigen-specific regulatory T cells (Tregs), using peptides such as Tregitopes (T regulatory cell epitopes) are under consideration for the future treatment of CRIM-negative Pompe disease. Tregitopes are natural T cell epitopes derived from immunoglobulin G (IgG) that cause the expansion and activation of regulatory T cells (Treg). Teaching the immune system to tolerate GAA by co-delivering GAA with Tregitope peptides might dramatically improve the lives of CRIM-negative babies and could be applied to other enzyme replacement therapies to which ADA have been induced

    Ultraviolet Signposts of Resonant Dynamics in the Starburst-Ringed Sab Galaxy, M94 (NGC 4736)

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    M94 (NGC 4736) is investigated using images from the Ultraviolet Imaging Telescope (FUV-band), Hubble Space Telescope (NUV-band), Kitt Peak 0.9-m telescope (H-alpha, R, and I bands), and Palomar 5-m telescope (B-band), along with spectra from the International Ultraviolet Explorer and Lick 1-m telescopes. The wide-field UIT image shows FUV emission from (a) an elongated nucleus, (b) a diffuse inner disk, where H-alpha is observed in absorption, (c) a bright inner ring of H II regions at the perimeter of the inner disk (R = 48 arcsec. = 1.1 kpc), and (d) two 500-pc size knots of hot stars exterior to the ring on diametrically opposite sides of the nucleus (R= 130 arcsec. = 2.9 kpc). The HST/FOC image resolves the NUV emission from the nuclear region into a bright core and a faint 20 arcsec. long ``mini-bar'' at a position angle of 30 deg. Optical and IUE spectroscopy of the nucleus and diffuse inner disk indicates an approximately 10^7 or 10^8 yr-old stellar population from low-level starbirth activity blended with some LINER activity. Analysis of the H-alpha, FUV, NUV, B, R, and I-band emission along with other observed tracers of stars and gas in M94 indicates that most of the star formation is being orchestrated via ring-bar dynamics involving the nuclear mini-bar, inner ring, oval disk, and outer ring. The inner starburst ring and bi-symmetric knots at intermediate radius, in particular, argue for bar-mediated resonances as the primary drivers of evolution in M94 at the present epoch. Similar processes may be governing the evolution of the ``core-dominated'' galaxies that have been observed at high redshift. The gravitationally-lensed ``Pretzel Galaxy'' (0024+1654) at a redshift of approximately 1.5 provides an important precedent in this regard.Comment: revised figure 1 (corrected coordinate labels on declination axis); 19 pages of text + 19 figures (jpg files); accepted for publication in A

    Prior tonsillectomy is associated with an increased risk of esophageal adenocarcinoma.

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    BACKGROUND: Esophageal cancer is a deadly cancer with 5-year survival METHODS: Cases included 452 esophagectomy cases, including 396 with EAC and 56 who underwent esophagectomy for Barrett\u27s esophagus (BE) with high grade dysplasia (HGD). 1,102 thoracic surgery patients with surgical indications other than dysplastic BE or esophageal cancer represented the controls for our analysis. The association of tonsillectomy and HGD/EAC were primarily evaluated by using univariate tests and then verified by logistic regression analysis. Baseline demographics, medical history, and thoracic surgery controls were compared by using χ2 tests or 95% CIs. Significant risk factors were considered as covariates in the multivariate models while evaluating the association between tonsillectomy and HGD/EAC. P-values or odds ratios were estimated with 95% confidence limits to identify significances which was more appropriate. RESULTS: Tonsillectomy was more common in cases than controls and was found to have a significant association with esophageal cancer (19.9% vs. 12.7%; p-value = 0.0003). This significant association persisted after controlling for other known risk factors/covariates. CONCLUSION: A prior history of tonsillectomy was significantly associated with HGD/EAC and may represent an independent risk factor for the development of EAC. However, the underlying biology driving this association remains unclear

    What Powers Ultra-luminous IRAS Galaxies?

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    We present an ISO SWS and ISOPHOT-S, mid-infrared spectroscopic survey of 15 ultra-luminous IRAS galaxies. We combine the survey results with a detailed case study, based on near-IR and mm imaging spectroscopy, of one of the sample galaxies (UGC 5101). We compare the near- and mid-IR characteristics of these ultra-luminous galaxies to ISO and literature data of thirty starburst and active galactic nuclei (AGN), template galaxies. We find that 1) 70-80% of the ultra-luminous IRAS galaxies in our sample are predominantly powered by recently formed massive stars. 20-30% are powered by a central AGN. These conclusions are based on a new infrared 'diagnostic diagram' involving the ratio of high to low excitation mid-IR emission lines on the one hand, and on the strength of the 7.7um PAH feature on the other hand. 2) at least half of the sources probably have simultaneously an active nucleus and starburst activity in a 1-2 kpc diameter circum-nuclear disk/ring. 3) the mid-infrared emitting regions are highly obscured. After correction for these extinctions, we estimate that the star forming regions in ULIRGs have ages between 10^7 and 10^8 years, similar to but somewhat larger than those found in lower luminosity starburst galaxies. 4) in the sample we have studied there is no obvious trend for the AGN component to dominate in the most compact, and thus most advanced mergers. Instead, at any given time during the merger evolution, the time dependent compression of the circum-nuclear interstellar gas, the accretion rate onto the central black hole and the associated radiation efficiency may determine whether star formation or AGN activity dominates the luminosity of the system.Comment: 63 pages postscript (ex. MS Word), 11 postscript and 2 gif figures, submitted to ApJ. See also http://www.mpe-garching.mpg.de/ISO/preprint/MPE-IR-97003.htm

    Sharks of the order Carcharhiniformes from the British Coniacian, Santonian and Campanian (Upper Cretaceous).

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    Bulk sampling of phosphate-rich horizons within the British Coniacian to Campanian (Upper Cretaceous) yielded very large samples of shark and ray teeth. All of these samples yielded teeth of diverse members of the Carcharhiniformes, which commonly dominate the fauna. The following species are recorded and described: Pseudoscyliorhinus reussi (Herman, 1977) comb. nov., Crassescyliorhinus germanicus (Herman, 1982) gen. nov., Scyliorhinus elongatus (Davis, 1887), Scyliorhinus brumarivulensis sp. nov., ? Palaeoscyllium sp., Prohaploblepharus riegrafi (MĂźller, 1989) gen. nov., ? Cretascyliorhinus sp., Scyliorhinidae inc. sedis 1, Scyliorhinidae inc. sedis 2, Pteroscyllium hermani sp. nov., Protoscyliorhinus sp., Leptocharias cretaceus sp. nov., Palaeogaleus havreensis Herman, 1977, Paratriakis subserratus sp. nov., Paratriakis tenuis sp. nov., Paratriakis sp. indet. and ? Loxodon sp. Taxa belonging to the families ?Proscylliidae, Leptochariidae, and Carcharhinidae are described from the Cretaceous for the first time. The evolutionary and palaeoecological implications of these newly recognised faunas are discussed

    Adaptive Optics Integral Field Spectroscopy of the Young Stellar Objects in LkH_alpha 225

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    Progress in understanding the embedded stars in LkHa225 has been hampered by their variability, making it hard to compare data taken at different times, and by the limited resolution of the available data, which cannot probe the small scales between the two stars. In an attempt to overcome these difficulties, we present new near-infrared data on this object taken using the ALFA adaptive optics system with the MPE 3D integral field spectrometer and the near-infrared camera Omega-Cass. The stars themselves have K-band spectra which are dominated by warm dust emission, analagous to class I-II for low mass YSOs, suggesting that the stars are in a phase where they are still accreting matter. On the other hand, the ridge of continuum emission between them is rather bluer, suggestive of extincted and/or scattered stellar light rather than direct dust emission. The compactness of the CO emission seen toward each star argues for accretion disks (which can also account for much of the K-band veiling) rather than a neutral wind. In contrast to other YSOs with CO emission, LkHa225 has no detectable Br_gamma emission. Additionally there is no H_2 detected on the northern star, although we do confirm that the strongest H_2 emission is on the southern star, where we find it is excited primarily by thermal mechanisms. A second knot of H_2 is observed to its northeast, with a velocity shift of -75kms and a higher fraction of non-thermal emission. This is discussed with reference to the H2O maser, the molecular outflow, and [S II] emission observed between the stars.Comment: to appear in ApJ, April 2001. 18 pages, including 6 figure

    Different pathways of molecular pathophysiology underlie cognitive and motor tauopathy phenotypes in transgenic models for Alzheimer’s disease and frontotemporal lobar degeneration

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    Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. Acknowledgments From the Berlin Laboratory, we thank Ingo Voigt for performing the injections of the two constructs into the oocytes, Bettina Seelhorst for her extensive technical assistance, Anna Thoma for taking specific care of the animals, and John Horn, Charite Core Facility for electron microscopy for performing expert analyses in ultra-cryosections with immunogold technique. Expert comments on the manuscript from Silke Frahm-Barske (Berlin) are also acknowledged. Special thanks to Bob Switzer at NeuroScience Associates Inc. for embedding, sectioning and staining mouse brains. This work was funded by TauRx Therapeutics, Singapore. C.R.H. and C.M.W. declare that they are officers in TauRx Therapeutics Ltd.Peer reviewedPublisher PD
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