85 research outputs found
OT J002656.6+284933 (CSS101212:002657+284933): An SU UMa-Type Dwarf Nova with Longest Superhump Period
We observed the 2016 outburst of OT J002656.6+284933
(CSS101212:002657+284933) and found that it has the longest recorded
[0.13225(1) d in average] superhumps among SU UMa-type dwarf novae. The object
is the third known SU UMa-type dwarf nova above the period gap. The outburst,
however, was unlike ordinary long-period SU UMa-type dwarf novae in that it
showed two post-outburst rebrightenings. It showed superhump evolution similar
to short-period SU UMa-type dwarf novae. We could constrain the mass ratio to
less than 0.15 (most likely between 0.10 and 0.15) by using superhump periods
in the early and post-superoutburst stages. These results suggest the
possibility that OT J002656.6+284933 has an anomalously undermassive secondary
and it should have passed a different evolutionary track from the standard one.Comment: 6 pages, 3 figures, accepted for publication in PASJ (Letters), Note
added in proof has been added. Supplementary Information (si.pdf) is
available in the source fil
Discovery of Negative Superhumps during a Superoutburst of January 2011 in ER Ursae Majoris
We report on a discovery of "negative" superhumps during the 2011 January
superoutburst of ER UMa. During the superoutburst which started on 2011 January
16, we detected negative superhumps having a period of 0.062242(9) d, shorter
than the orbital period by 2.2%. No evidence of positive superhumps was
detected during this observation. This finding indicates that the disk
exhibited retrograde precession during this superoutburst, contrary to all
other known cases of superoutbursts. The duration of this superoutburst was
shorter than those of ordinary superoutbursts and the intervals of normal
outbursts were longer than ordinary ones. We suggest a possibility that such
unusual outburst properties are likely a result of the disk tilt, which is
supposed to be a cause of negative superhumps: the tilted disk could prevent
the disk from being filled with materials in the outmost region which is
supposed to be responsible for long-duration superoutbursts in ER UMa-type
dwarf novae. The discovery signifies the importance of the classical prograde
precession in sustaining long-duration superoutbursts. Furthermore, the
presence of pronounced negative superhumps in this system with a high
mass-transfer rate favors the hypothesis that hydrodynamical lift is the cause
of the disk tilt.Comment: 8 pages, 3 figures, Accepted for publication in PASJ Lette
Gastric T-cell lymphoma associated with hemophagocytic syndrome
BACKGROUND: Lymphoma-associated hemophagocytic syndrome (LAHS) occurs in mostly extra nodal non-Hodgkin's lymphoma. LAHS arising from gastrointestinal lymphoma has never been reported. Here we report a case of gastric T-cell lymphoma-associated hemophagocytic syndrome. CASE PRESENTATION: A 51-year-old woman presented with pain, redness of breasts, fever and hematemesis. Hematological examination revealed anemia. Gastroscopy revealed small bleeding ulcers in the stomach and the computed tomography scan showed liver tumor. She underwent total gastrectomy for gastrointestinal bleeding and the histopathology revealed gastric T-cell lymphoma. She continued to bleed from the anastomosis and died on the 8th postoperative day. Autopsy revealed it to be a LAHS. CONCLUSIONS: If Hemophagocytic syndrome (HPS) occurs in lymphoma of the gastrointestinal tract, bleeding from the primary lesion might be uncontrollable. Early diagnosis and appropriate treatment are needed for long-term survival
Roles of Macrophages in Advanced Liver Fibrosis, Identified Using a Newly Established Mouse Model of Diet-Induced Non-Alcoholic Steatohepatitis
Macrophages play critical roles in the pathogenesis of non-alcoholic steatohepatitis (NASH). However, it is unclear which macrophage subsets are critically involved in the development of inflammation and fibrosis in NASH. In TSNO mice fed a high-fat/cholesterol/cholate-based diet, which exhibit advanced liver fibrosis that mimics human NASH, we found that Kupffer cells (KCs) were less abundant and recruited macrophages were more abundant, forming hepatic crown-like structures (hCLS) in the liver. The recruited macrophages comprised two subsets: CD11c+/Ly6C−and CD11c− /Ly6C+ cells. CD11c+ cells were present in a mesh-like pattern around the lipid droplets, constituting the hCLS. In addition, CD11c+ cells colocalized with collagen fibers, suggesting that this subset of recruited macrophages might promote advanced liver fibrosis. In contrast, Ly6C+cells were present in doughnut-like inflammatory lesions, with a lipid droplet in the center. Finally, RNA sequence analysis indicates that CD11c+/Ly6C− cells promote liver fibrosis and hepatic stellate cell (HSC) activation, whereas CD11c−/Ly6C+ cells are a macrophage subset that play an anti-inflammatory role and promote tissue repair in NASH. Taken together, our data revealed changes in liver macrophage subsets during the development of NASH and shed light on the roles of the recruited macrophages in the pathogenesis of advanced fibrosis in NASH
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