780 research outputs found
Search for the Infrared Emission Features from Deuterated Interstellar Polycyclic Aromatic Hydrocarbons
We report the results of a search for emission features from interstellar
deuterated polycyclic aromatic hydrocarbons (PAHs) in the 4um region with the
Infrared Camera (IRC) onboard AKARI. No significant excess emission is seen in
4.3-4.7um in the spectra toward the Orion Bar and M17 after the subtraction of
line emission from the ionized gas. A small excess of emission remains at
around 4.4 and 4.65um, but the ratio of their intensity to that of the band
emission from PAHs at 3.3-3.5um is estimated as 2-3%. This is an order of
magnitude smaller than the values previously reported and also those predicted
by the model of deuterium depletion onto PAHs. Since the subtraction of the
ionized gas emission introduces an uncertainty, the deuterated PAH features are
also searched for in the reflection nebula GN 18.14.0, which does not show
emission lines from ionized gas. We obtain a similar result that excess
emission in the 4um region, if present, is about 2% of the PAH band emission in
the 3um region. The present study does not find evidence for the presence of
the large amount of deuterated PAHs that the depletion model predicts. The
results are discussed in the context of deuterium depletion in the interstellar
medium.Comment: 24 pages, 6 figures, to appear in Ap
Unusual Carbonaceous Dust Distribution in PN G095.2+00.7
We investigate the polycyclic aromatic hydrocarbon features in the young
Galactic planetary nebula PN G095.2+00.7 based on mid-infrared observations.
The near- to mid-infrared spectra obtained with the AKARI/IRC and the
Spitzer/IRS show the PAH features as well as the broad emission feature at 12
{\mu}m usually seen in proto-planetary nebulae (pPNe). The spatially resolved
spectra obtained with Subaru/COMICS suggest that the broad emission around 12
{\mu}m is distributed in a shell-like structure, but the unidentified infrared
band at 11.3 {\mu}m is selectively enhanced at the southern part of the nebula.
The variation can be explained by a difference in the amount of the UV
radiation to excite PAHs, and does not necessarily require the chemical
processing of dust grains and PAHs. It suggests that the UV self-extinction is
important to understand the mid-infrared spectral features. We propose a
mechanism which accounts for the evolutionary sequence of the mid-infrared dust
features seen in a transition from pPNe to PNe.Comment: 6 pages, 4 figure
Autoimmune hemolytic anemia occurred prior to evident nephropathy in a patient with chronic hepatitis C virus infection: case report
BACKGROUND: Renal involvement in patients with chronic hepatitis C virus infection has been suggested to be due to a variety of immunological processes. However, the precise mechanism by which the kidneys are damaged in these patients is still unclear. CASE PRESENTATION: A 66 year old man presented with the sudden onset of autoimmune hemolytic anemia. Concomitant with a worsening of hemolysis, his initially mild proteinuria and hemoglobinuria progressed. On admission, laboratory tests revealed that he was positive for hepatitis C virus in his blood, though his liver function tests were all normal. The patient displayed cryoglobulinemia and hypocomplementemia with cold activation, and exhibited a biological false positive of syphilic test. Renal biopsy specimens showed signs of immune complex type nephropathy with hemosiderin deposition in the tubular epithelial cells. CONCLUSIONS: The renal histological findings in this case are consistent with the deposition of immune complexes and hemolytic products, which might have occurred as a result of the patient's underlying autoimmune imbalance, autoimmune hemolytic anemia, and chronic hepatitis C virus infection
Gunning-Narasimhan's theorem with a growth condition
Given a compact Riemann surface X and a point x_0 in X, we construct a
holomorphic function without critical points on the punctured Riemann surface R
= X - x_0 which is of finite order at the point x_0. This complements the
result of Gunning and Narasimhan from 1967 who constructed a noncritical
holomorphic function on every open Riemann surface, but without imposing any
growth condition. On the other hand, if the genus of X is at least one, then we
show that every algebraic function on R admits a critical point. Our proof also
shows that every cohomology class in H^1(X;C) is represented as a de Rham class
by a nowhere vanishing holomorphic one-form of finite order on the punctured
surface X-x_0.Comment: J. Geom. Anal., in pres
Bergman kernel and complex singularity exponent
We give a precise estimate of the Bergman kernel for the model domain defined
by where
is a holomorphic map from to ,
in terms of the complex singularity exponent of .Comment: to appear in Science in China, a special issue dedicated to Professor
Zhong Tongde's 80th birthda
Itinerant ferromagnetism in half-metallic CoS_2
We have investigated electronic and magnetic properties of the pyrite-type
CoS_2 using the linearized muffin-tin orbital (LMTO) band method. We have
obtained the ferromagnetic ground state with nearly half-metallic nature. The
half-metallic stability is studied by using the fixed spin moment method. The
non-negligible orbital magnetic moment of Co 3d electrons is obtained as in the local spin density approximation (LSDA). The calculated
ratio of the orbital to spin angular momenta / = 0.15 is
consistent with experiment. The effect of the Coulomb correlation between Co 3d
electrons is also explored with the LSDA + U method. The Coulomb correlation at
Co sites is not so large, eV, and so CoS_2 is possibly
categorized as an itinerant ferromagnet. It is found that the observed
electronic and magnetic behaviors of CoS_2 can be described better by the LSDA
than by the LSDA + U.Comment: 4 pages, 3 postscript figure
Membranous nephropathy in a patient with hereditary angioedema: a case report
<p>Abstract</p> <p>Introduction</p> <p>Hereditary angioedema is the commonest inherited disorder of the complement system and has been associated with several immune glomerular diseases. A case of nephrotic syndrome and renal impairment due to idiopathic membranous glomerulonephritis in a patient with hereditary angioedema has not been described before.</p> <p>Case presentation</p> <p>We present the first reported case of the association of membranous nephropathy and hereditary angioedema in a 43-year-old male Caucasian patient who presented with acute intestinal angioedema, hypertension, acute pancreatitis, renal impairment and generalised body swelling due to severe nephrotic syndrome. We present the challenges involved in the clinical management of the patient.</p> <p>Conclusion</p> <p>This patient's presentation with severe nephrotic syndrome, renal impairment and hypertension required aggressive treatment of the membranous nephropathy given the high risk for progression to end stage renal failure. The contraindication to angiotensin converting enzyme inhibitors and angiotensin II receptor blockers in this patient, the lack of published evidence on the use of alkylating agents and other immunosuppressive agents in patients with hereditary angioedema and the lack of published data on the management of similar cases presented a clinical challenge in this patient's management.</p
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