323 research outputs found
Atypical propylthiouracil-induced ANCA-positive vasculitis: report of a case with unusual clinical and histopathologic findings
The side effects of propylthiouracil, including cytopenia and vasculitis, are well established. We present an interesting case in which cytopenia and cutaneous vasculopathy occurred concomitantly in a critically ill patient. The patient was initially treated for suspected infection until dermatologic and rheumatologic workup revealed ANCA-positivity and vasculopathy on histopathology, most consistent with an atypical presentation of ANCA-positive vasculitis. Upon initiation of immunosuppressive therapy, the patient’s condition rapidly improved emphasizing the importance of early recognition of this condition
Late Paleocene Flora of the Northern Alaska Peninsula: The Role of Transberingian Plant Migrations and Climatic Change
For the first time, the Late Sagwon Flora is described from the upper beds of the Prince Creek Formation (Upper Paleocene) at the Sagavanirktok River (northern Alaska Peninsula). The flora is dominated by the angiosperm Tiliaephyllum brooksense Moiseeva et Herman sp. nov. and conifer Metasequoia occidentalis (Newb.) Chaney. The Late Sagwon Flora is most similar to the Danian or Danian-Selandian flora from the middle part of the Upper Tsagayan Subformation (Amur Region) and lower part of the Wuyun Formation (Heilongjiang Province, China). This similarity allows us to hypothesize that the genus Tiliaephyllum, which dominated in the Late Tsagayan Flora, migrated via the Bering Land Bridge from southern paleolatitudes of the Far East to high latitudes of the Arctic Pacific, due to the progressively warming climate of the Paleocene. Additional new angiosperm species are described from the Late Sagwon Flora: Archeampelos mullii Moiseeva et Herman sp. nov., Tiliaephyllum brooksense Moiseeva et Herman sp. nov., and Dicotylophyllum sagwonicum Moiseeva et Herman sp. nov
Near-threshold production of -mesons in and NN collisions and -mixing
We consider near-threshold -meson production in and
collisions. An effective Lagrangian approach with one-pion exchange is applied
to analyze different contributions to the cross section for different isospin
channels. The Reggeon exchange mechanism is also evaluated for comparison. The
results from reactions are used to calculate the contribution of the
meson to the cross sections and invariant mass distributions
of the reactions and . It is found that
the experimental observation of mesons in the reaction is much more promising than the observation of mesons in
the reaction . Effects of isospin violation in the reactions
, , and , which are induced by -- mixing, are also analyzed.Comment: 43 pages, including 16 eps figures, to be bublished in Phys. Atom.
Nucl. (Yad. Fiz.) vol. 65, No. 11 (2002
Annihilation range and final-state interaction in the antiproton-proton annihilation into pi-pi+
The large set of accurate data on differential cross section and analyzing
power from the CERN LEAR experiment on in the range
from 360 to 1550 MeV/c is well reproduced within a distorted wave approximation
approach. The initial scattering wave functions originate from a
recent model. The transition operator is obtained from a combination
of the and quark-antiquark annihilation mechanisms. A good fit
to the data, in particular the reproduction of the double dip structure
observed in the analyzing powers, requires quark wave functions for proton,
antiproton, and pions with radii slightly larger than the respective measured
charge radii. This corresponds to an increase in range of the annihilation
mechanisms and consequently the amplitudes for total angular momentum J=2 and
higher are much larger than in previous approaches. The final state
wave functions, parameterized in terms of phase shifts and
inelasticities, are also a very important ingredient for the fine tuning of the
fit to the observables.Comment: 11 pages, 11 figures (Revtex 4), revised version with one additional
figure. Accepted for publication in PR
Value of prominent flow voids without cord edema in the detection of spinal arteriovenous fistulae
Purpose: To determine the prevalence of spinal dural arteriovenous fistulae (SDAVF) in patients presenting with prominent vascular flow voids on imaging without other imaging findings suggestive of SDAVF. Methods: We retrospectively identified patients from January 1, 2005 to March 1, 2012 who underwent spinal angiography for suspected SDAVF with prominent vascular flow voids on prior imaging. We excluded patients with other major spinal pathology or other imaging findings of SDAVF including cord hyperintensity, enhancement, or expansion. We calculated the proportion of patients with positive findings for SDAVF on angiography and evaluated the prevalence of SDAVF for this finding alone and in correlation with clinical findings. Results: 18 patients underwent spinal angiography for prominent flow voids on imaging without other spinal pathology or imaging findings of SDAVF. Three had a SDAVF detected on angiography. The prevalence of SDAVF in this population was low, only 17% (95% CI 6-39%). All of the patients with positive angiography findings had myelopathy, increasing the prevalence to 100% if the additional clinical finding of myelopathy was present. Conclusions: Prominent flow voids without other imaging findings suggestive of SDAVF is poorly predictive of the presence of a SDAVF, unless myelopathy is present clinically. © 2014 Alhilali et al
Near threshold enhancement of the ppbar mass spectrum in J/Psi decay
We investigate the nature of the near-threshold enhancement in the ppbar
invariant mass spectrum of the reaction J/Psi -> gamma ppbar reported recently
by the BES Collaboration. Using the Juelich NNbar model we show that the mass
dependence of the ppbar spectrum close to the threshold can be reproduced by
the S-wave ppbar final state interaction in the isospin I=1 state within the
Watson-Migdal approach. However, because of our poor knowledge of the NNbar
interaction near threshold and of the J/Psi -> gamma ppbar reaction mechanism
and in view of the controversal situation in the decay J/Psi -> pi0 ppbar,
where no obvious signs of a ppbar final state interaction are seen,
explanations other than final state interactions cannot be ruled out at the
present stage.Comment: 9 pages, 7 figure
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