135 research outputs found
Malignant Pigmented Villonodular Synovitis in the Knee - Report of a Case with Rapid Clinical Progression
Malignant pigmented villonodular synovitis (PVNS) (or malignant giant cell tumor of tendon sheath (GCTTS) is an extremely rare condition defined as a malignant lesion occurring with concomitant or previously documented PVNS at the same site. To date, only less than 20 cases have been reported in English literatures. We report a case of malignant PVNS in the knee in a 56-year-old woman with unpredictable rapid progression. This case raised a caution that when atypical components in specimens of recurrent benign PVNS are detected, even if low-grade or tiny, both pathologists and surgeons should consider the risk of malignant PVNS, which could display aggressive clinical progression
薬剤性過敏症症候群(DIHS)の皮疹部においてCD3陽性T細胞数に対するFoxP3陽性制御性T細胞数の割合は増加している
博士(医学)・甲第604号・平成25年11月27日© 2014 British Association of Dermatologists / The definitive version is available at http://onlinelibrary.wiley.com
The ALMA Survey of 70 m Dark High-mass Clumps in Early Stages (ASHES). XI. Statistical Study of Early Fragmentation
Fragmentation during the early stages of high-mass star formation is crucial
for understanding the formation of high-mass clusters. We investigated
fragmentation within thirty-nine high-mass star-forming clumps as part of the
Atacama Large Millimeter/submillimeter Array (ALMA) Survey of 70 m Dark
High-mass Clumps in Early Stages (ASHES). Considering projection effects, we
have estimated core separations for 839 cores identified from the continuum
emission and found mean values between 0.08 and 0.32 pc within each clump. We
find compatibility of the observed core separations and masses with the thermal
Jeans length and mass, respectively. We also present sub-clump structures
revealed by the 7 m-array continuum emission. Comparison of the Jeans
parameters using clump and sub-clump densities with the separation and masses
of gravitationally bound cores suggests that they can be explained by clump
fragmentation, implying the simultaneous formation of sub-clumps and cores
within rather than a step-by-step hierarchical fragmentation. The number of
cores in each clump positively correlates with the clump surface density and
the number expected from the thermal Jeans fragmentation. We also find that the
higher the fraction of protostellar cores, the larger the dynamic range of the
core mass, implying that the cores are growing in mass as the clump evolves.
The ASHES sample exhibits various fragmentation patterns: aligned, scattered,
clustered, and sub-clustered. Using the Q-parameter, which can help to
distinguish between centrally condensed and subclustered spatial core
distributions, we finally find that in the early evolutionary stages of
high-mass star formation, cores tend to follow a subclustered distribution.Comment: Accepted for Publication in ApJ. 19 pages, 7 figures, 4 table
Digging into the Interior of Hot Cores with ALMA: Spiral Accretion into the High-mass Protostellar Core G336.01-0.82
We observed the high-mass star-forming core G336.01-0.82 at 1.3 mm and 0.05''
(~150 au) angular resolution with the Atacama Large Millimeter/submillimeter
Array (ALMA) as part of the Digging into the Interior of Hot Cores with ALMA
(DIHCA) survey. These high-resolution observations reveal two spiral streamers
feeding a circumstellar disk at opposite sides in great detail. Molecular line
emission from CHOH shows velocity gradients along the streamers consistent
with infall. Similarly, a flattened envelope model with rotation and infall
implies a mass larger than 10 M for the central source and a
centrifugal barrier of 300 au. The location of the centrifugal barrier is
consistent with local peaks in the continuum emission. We argue that gas
brought by the spiral streamers is accumulating at the centrifugal barrier,
which can result in future accretion burst events. A total high infall rate of
~ M yr is derived by matching models to the
observed velocity gradient along the streamers. Their contribution account for
20-50% the global infall rate of the core, indicating streamers play an
important role in the formation of high-mass stars.Comment: 11 pages, 5 figures, 2 appendices. Accepted for publication in ApJL.
Interactive figure available at https://folguinch.github.io/projects/dihc
The ALMA Survey of 70 {\mu}m Dark High-mass Clumps in Early Stages (ASHES). X: Hot Gas Reveals Deeply Embedded Star Formation
Massive infrared dark clouds (IRDCs) are considered to host the earliest
stages of high-mass star formation. In particular, 70 m dark IRDCs are the
colder and more quiescent clouds. At a scale of about 5000 au using
formaldehyde (H2CO) emission, we investigate the kinetic temperature of dense
cores in 12 IRDCs obtained from the pilot ALMA Survey of 70 m dark
High-mass clumps in Early Stages (ASHES). Compared to 1.3 mm dust continuum and
other molecular lines, such as C18O and deuterated species, we find that H2CO
is mainly sensitive to low-velocity outflow components rather than to quiescent
gas expected in the early phases of star formation. The kinetic temperatures of
these components range from 26 to 300 K. The Mach number reaches about 15 with
an average value of about 4, suggesting that the velocity distribution of gas
traced by H2CO is significantly influenced by a supersonic non-thermal
component. In addition, we detect warm line emission from HC3N and OCS in 14
protostellar cores, which requires high excitation temperatures (Eu/k ~ 100 K).
These results show that some of the embedded cores in the ASHES fields are in
an advanced evolutionary stage, previously unexpected for 70 m dark IRDCs.Comment: Accepted for Publication in ApJ. 39 pages, 22 figures, 6 table
The ALMA Survey of 70 Dark High-mass Clumps in Early Stages (ASHES). II: Molecular Outflows in the Extreme Early Stages of Protocluster Formation
We present a study of outflows at extremely early stages of high-mass star
formation obtained from the ALMA Survey of 70 dark High-mass clumps
in Early Stages (ASHES). Twelve massive 3.670 dark prestellar
clump candidates were observed with the Atacama Large Millimeter/submillimeter
Array (ALMA) in Band 6. Forty-three outflows are identified toward 41 out of
301 dense cores using the CO and SiO emission lines, yielding a detection rate
of 14%. We discover 6 episodic molecular outflows associated with low- to
high-mass cores, indicating that episodic outflows (and therefore episodic
accretion) begin at extremely early stages of protostellar evolution for a
range of core masses. The time span between consecutive ejection events is much
smaller than those found in more evolved stages, which indicates that the
ejection episodicity timescale is likely not constant over time. The estimated
outflow dynamical timescale appears to increase with core masses, which likely
indicates that more massive cores have longer accretion timescales than less
massive cores. The lower accretion rates in these 70 dark objects
compared to the more evolved protostars indicate that the accretion rates
increase with time. The total outflow energy rate is smaller than the turbulent
energy dissipation rate, which suggests that outflow induced turbulence cannot
sustain the internal clump turbulence at the current epoch. We often detect
thermal SiO emission within these 70 dark clumps that is unrelated
to CO outflows. This SiO emission could be produced by collisions, intersection
flows, undetected protostars, or other motions.Comment: 32 pages, 9 figures, 4 tables, accepted for publication in Ap
Natural evolution of desmoplastic fibroblastoma on magnetic resonance imaging: a case report
<p>Abstract</p> <p>Introduction</p> <p>Desmoplastic fibroblastoma (collagenous fibroma) is a recently described tumor thought to arise predominantly from subcutaneous tissue or skeletal muscle. The natural evolution of this tumor on magnetic resonance imaging has never been described, to the best of our knowledge. We herein report a case of desmoplastic fibroblastoma arising in the thigh and show the longitudinal magnetic resonance imaging findings.</p> <p>Case presentation</p> <p>A 60-year-old Japanese man presented with swelling of the medial side of his right thigh, and he complained of nighttime pain and slight tenderness. Magnetic resonance imaging demonstrated a 4 × 4 cm mass in the right thigh. Open biopsy was performed. The mass was diagnosed histologically as a benign fibrous tumor, and we maintained follow-up without surgical therapy. After one year, magnetic resonance imaging showed an increase in tumor size to 4 × 5 cm, but the histologic findings were the same as those obtained one year earlier. Resection was performed with narrow surgical margins. Pathologic diagnosis was desmoplastic fibroblastoma. Two years after surgery, the patient is free from pain and shows no signs or symptoms of recurrence.</p> <p>Conclusion</p> <p>The natural evolution of desmoplastic fibroblastoma is characterized by no changes in patterns on magnetic resonance imaging despite increasing size. This finding is clinically helpful for distinguishing desmoplastic fibroblastoma with increasing pain from the desmoid tumor.</p
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