223 research outputs found
Diffusion of Ultra High Energy Protons in Galaxy Clusters and Secondary X and Gamma Ray Emissions
In this work we simulate the propagation of Ultra High Energy (UHE) protons
in the magnetised intergalactic medium of Galaxy Clusters (GCs). Differently
from previous works on the subject, we trace proton trajectories in
configurations of the Intra Cluster Magnetic Field (ICMF) which have been
extracted from a constrained Magnetic-SPH simulation of the local universe.
Such an approach allows us to take into account the effects of several features
of the ICMFs, e.g. irregular geometrical structure and field fluctuations due
to merger shocks,which cannot be investigated analitically or with usual
numerical simulations. Furthermore, we are able to simulate a set of clusters
which have properties quite similar to those of GCs observed in the nearby
universe. We estimate the time that UHE protons take to get out of the clusters
and found that in the energy range 5\times 10^{18} \simleq E \simleq 3 \times
10^{19} \eV proton propagation takes place in the Bohm scattering diffusion
regime passing smoothly to a small pitch angle diffusion regime at larger
energies.
We apply our results to estimate the secondary gamma and Hard X Ray (HXR)
emissions produced by UHE protons in a rich GC. We show that the main emission
channel is due to the synchrotron HXR radiation of secondary electrons
originated by proton photo-pair production scattering onto the CMB. This
process may give rise to a detectable signal if a relatively powerful AGN, or a
dead quasar, accelerating protons at UHEs is harboured by a rich GC in the
local universe.Comment: 27 pages, 13 figure
Measurement of interleukin 1 alpha and 1 beta (IL-1 alpha and IL-1 beta) in human cystic lésions of the jaw. Implications for the pathogenesis of radicular cysts
Human radicular cystic tissue of jaws was found to contain between 0.823 pg/mg to 18.026 pg/mg interleukin 1 beta and from 0.34 pg/mg to 0.708 pg/mg interleukin 1 alpha.No IL-1 beta and alpha could be found in specimens from healthy patients. A finding which may be extremely relevant in cystic growth and episodes of alveolar bone resorption around the cystic lesion.Human radicular cystic tissue of jaws was found to contain between 0.823 pg/mg to 18.026 pg/mg interleukin 1 beta and from 0.34 pg/mg to 0.708 pg/mg interleukin 1 alpha.No IL-1 beta and alpha could be found in specimens from healthy patients. A finding which may be extremely relevant in cystic growth and episodes of alveolar bone resorption around the cystic lesion.Les tissus des kystes radiculaires chez lâhomme contiennent 0,823 Ă 18,026 pg/mg dâinterleukines 1 beta et 0,34 Ă 0,708 pg/mg dâinterleukines alpha. Il nâa pas Ă©tĂ© trouvĂ© dâIL-1 beta et alpha dans des prĂ©lĂšvements effectuĂ©s chez des individus sains. Cette constatation peut avoir des consĂ©quences importantes en relation avec la croissance du kyste et la rĂ©sorption de lâos alvĂ©olaire avoisinant
123I-Methyljodbenzylguanidin- (MIBG-) Szintigraphie: Paradoxe Nuklidspeicherung eines onkozytÀren Nebennierenrindenkarzinoms
Zusammenfassung: Das mit Radiojod markierte Katecholaminanalogon Methyljodbenzylguanidin (MIBG) eignet sich aufgrund seiner selektiven Aufnahme in chromaffine Gewebe in hervorragender Weise fĂŒr die bildgebende Diagnostik des PhĂ€ochromozytoms und besitzt hier nach Literaturangaben eine SensitivitĂ€t von etwa 90% und eine SpezifitĂ€t von annĂ€hernd 100%. Die falsch-positive oder paradoxe MIBG-Speicherung einer adrenokortikalen Neoplasie stellt demgegenĂŒber eine RaritĂ€t dar. Wir berichten ĂŒber diese Situation am Beispiel eines metastasierten onkozytĂ€ren Nebennierenrindenkarzinoms mit teilweise therapeutisch genutzter MIBG-Speicherung in verschiedenen Tumormanifestatione
METHOTREXATE ACTION IN RHEUMATOID ARTHRITIS: STIMULATION OF CYTOKINE INHIBITOR AND INHIBITION OF CHEMOKINE PRODUCTION BY PERIPHERAL BLOOD MONONUCLEAR CELLS
This open label study examines whether methotrexate (MTX) treatment modulates ex vivo synthesis of interleukin-1 receptor antagonist (IL-lra), soluble tumour necrosis factor receptors(sTNFR p55 and p75), interleukin-1ÎČ (IL-1ÎČ), tumour necrosis factor α(TNF-α), interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) by peripheral blood mononuclear cells (PBMC} and whether changes reflect clinical response. Significant stimulation of IL-lra and sTNFR p75 as well as inhibition of IL-8 production of PBMC were associated with clinical improvement observed in patients treated with MTX. When defining the characteristics of patients at study entry retrospectively in responders and non-responders a significantly lower ratio of IL-lra :IL-1ÎČ production before and its increase upon treatment was associated with clinical response in 13 patients compared to five patients not responding to MTX. In addition, clinical improvement was associated with decreased synthesis of IL-1ÎČ, TNF-α and IL-8 induced by bacterial lipopolysaccharide, IL-1α and IL-1ÎČ in PBMC in vitro. These findings suggest that MTX therapy reverses the inflammatory type of rheumatoid arthritis (RA) blood mononuclear cells by stimulating cytokine inhibitor production while inhibiting inflammatory cytokine release at the same time. This may explain the powerful anti-inflammatory properties of low-dose MTX as observed in most RA patients. Pretreatment determination of the IL-lra: IL-1ÎČ ratio in PBMC may be predictive with regard to a favourable therapeutic response and therefore may be useful for the selection of RA patients to be treated with MT
Constrained Simulations of the Magnetic Field in the Local Universe and the Propagation of UHECRs
We use simulations of LSS formation to study the build-up of magnetic fields
(MFs) in the ICM. Our basic assumption is that cosmological MFs grow in a MHD
amplification process driven by structure formation out of a seed MF present at
high z. Our LCDM initial conditions for the density fluctuations have been
statistically constrained by the observed galaxies, based on the IRAS 1.2-Jy
all-sky redshift survey. As a result, prominent galaxy clusters in our
simulation coincide closely with their real counterparts. We find excellent
agreement between RMs of our simulated clusters and observational data. The
improved resolution compared to previous work also allows us to study the MF in
large-scale filaments, sheets and voids. By tracing the propagation of UHE
protons in the simulated MF we construct full-sky maps of expected deflection
angles of protons with arrival energies E=1e20eV and 4e19eV, respectively.
Strong deflections are only produced if UHE protons cross clusters, however
covering only a small area on the sky. Multiple crossings of sheets and
filaments over larger distances may give rise to noticeable deflections,
depending on the model adopted for the magnetic seed field. Based on our
results we argue that over a large fraction of the sky the deflections are
likely to remain smaller than the present experimental angular sensitivity.
Therefore, we conclude that forthcoming air shower experiments should be able
to locate sources of UHE protons and shed more light on the nature of
cosmological MFs.Comment: 3revised version, JCAP, accepte
Ultra-High Energy Cosmic Ray Nuclei from Individual Magnetized Sources
We investigate the dependence of composition, spectrum and angular
distributions of ultra-high energy cosmic rays above 10^19 eV from individual
sources on their magnetization. We find that, especially for sources within a
few megaparsecs from the observer, observable spectra and composition are
severely modified if the source is surrounded by fields of ~ 10^-7 Gauss on
scales of a few megaparsecs. Low energy particles diffuse over larger distances
during their energy loss time. This leads to considerable hardening of the
spectrum up to the energy where the loss distance becomes comparable to the
source distance. Magnetized sources thus have very important consequences for
observations, even if cosmic rays arrive within a few degrees from the source
direction. At the same time, details in spectra and chemical composition may be
intrinsically unpredictable because they depend on the unknown magnetic field
structure. If primaries are predominantly nuclei of atomic mass A accelerated
up to a maximum energy E_max with spectra not much softer than E^-2, secondary
protons from photo-disintegration can produce a conspicuous peak in the
spectrum at energy ~ E_max/A. A related feature appears in the average mass
dependence on energy.Comment: 15 pages, 16 ps figures, published version with minor changes, see
http://stacks.iop.org/1475-7516/2004/i=08/a=01
Late term tolerance in head neck cancer patients irradiated in the IMRT era
BACKGROUND: The aim was to quantify severe transient and persisting late term effects in our single institution head neck cancer (HNC) cohort treated with curatively intended intensity modulated radiation therapy (IMRT). Hypothesis was if a 2-year follow up (FU) is sufficient to estimate the long term tolerance in HNC irradiated in the IMRT era. METHODS: Between 01/2002-8/2012, 707/1211 (58%) consecutively treated IMRT patients met the inclusion criteria of a FU time >12 months and loco-regional disease control (LRC). 45% presented with loco-regionally advanced disease; 55% were referred for curative definitive IMRT (66Gy-72Gy in 30--35 fractions), 45% underwent postoperative IMRT (60-66Gy in 30--33 fractions). Systemic concomitant therapy was administered in 85%. Highly consistent treatment procedures were performed with respect to contouring processes, dose constraints, radiation schedules, and the use of systemic therapy. Grade 3/4 late term effects were prospectively assessed and analyzed with respect to subgroups at particular risk for specific late effects. RESULTS: Mean/median FU of the cohort was 41/35 months (15--124). 13% of the patients (92/707) experienced any grade 3/4 late effects (101 events in 92/707 patients), 81% in the first 12 months after radiation. 4% of all developed persisting late grade 3/4 effects (25 events in 25/707 patients). CONCLUSIONS: IMRT led to a high late term tolerance in loco-regionally disease free HNC patients. The onset of any G3/4 effects showed a plateau at 2 years. The question of the cervical vessel tolerance in disease free long time survivors is still open and currently under evaluation at our institution
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