5,065 research outputs found
Metastatic carcinoma of the oral region : an analysis of 21 cases
Metastatic carcinoma to the jaws and oral region are very rare, representing less than 1% of all oral tumors. Unfortunately, oral metastasis is usually manifestation of an advanced stage of primary cancer, and indicates widespread disease and poor prognosis. In this retrospective study, a total of 2039 patients with history of oral malignant tumor between 1980 and 2012 at Seoul National University Dental Hospital were evaluated. We analyzed the dental and medical records, and histopathological database of 2039 patients to assess the prevalence of oral metastasis of carcinoma in terms of sex and age, as well as, the most common origin of primary cancer, and prevalent site and histopathological type of metastatic carcinoma. Among 2039 patients, 21 (1.03%) were finally diagnosed with metastatic carcinoma of the jaws and oral region. Among the 21 patients, only 11 had a working diagnosis as oral metastasis upon clinical evaluation before performing a biopsy. The mean age at the time of diagnosis with a metastatic carcinoma was 56.86, and there was a male preponderance. Metastatic carcinoma was more frequent in the jaws than in the soft tissue, especially in the mandible compared to the maxilla. The most frequent primary site was the lungs, followed by the liver and breasts. The predominant histopathological types were hepatocellular carcinoma and adenocarcinoma. Patient outcomes indicated a poor prognosis with the time from the appearance of the metastasis to death was only 12 months. According to these cases, oral metastases of carcinoma were exceedingly rare in Koreans. It can allow the clinicians take into account the possible presence of metastases and lead to early diagnosis
Competition between structural distortion and magnetic moment formation in fullerene C
We investigated the effect of on-site Coulomb interactions on the structural
and magnetic ground state of the fullerene C based on
density-functional-theory calculations within the local density approximation
plus on-site Coulomb corrections (LDA+). The total energies of the high
symmetry () and distorted () structures of C were
calculated for different spin configurations. The ground state configurations
were found to depend on the forms of exchange-correlation potentials and the
on-site Coulomb interaction parameter , reflecting the subtle nature of the
competition between Jahn-Teller distortion and magnetic instability in
fullerene C. While the non-magnetic state of the distorted
structure is robust for small , a magnetic ground state of the undistorted
structure emerges for larger than 4 eV when the LDA
exchange-correlation potential is employed.Comment: 4 figures, 1 tabl
The Light and Period Variations of the Eclipsing Binary AA Ursae Majoris
We present new multiband CCD photometry for AA UMa made on 8 nights between
January and March 2009; the light curves are the first ever compiled.
Historical light curves, as well as ours, display partial eclipses and inverse
O'Connell effects with Max I fainter than Max II. Among possible spot models, a
cool spot on either of the component stars and its variability with time permit
good light-curve representations for the system. A total of 194 eclipse timings
over 81 yrs, including our five timings, were used for ephemeris computations.
We found that the orbital period of the system has varied due to a periodic
oscillation overlaid on an upward parabolic variation. The continuous period
increase at a fractional rate of 1.310 is consistent with
that calculated from the W-D code and can be interpreted as a thermal mass
transfer from the less to the more massive secondary star at a rate of
6.610 M yr. The periodic component is in
satisfactory accord with a light-time effect due to an unseen companion with a
period of 28.2 yrs, a semi-amplitude of 0.007 d, and a minimum mass of =0.25 but this period variation could also arise from
magnetic activity.Comment: 23 pages, including 5 figures and 8 tables, accepted for publication
in PAS
Access to UG in the Acquisition of Long-Distance Wh-Questions of L3 English by L1 Mongolian Learners
This study examines a peculiar L3 error in the production of long-distance (LD) wh-questions in English, which does not seem to arise out of L1 Mongolian or L2 Russian. The linguistic behavior anticipated in Universal Grammar was to mark the LD wh-questions in English with a wh-expletive sort of what in matrix clause and with the meaningful wh-word in embedded clause such as *What do you think who Julianne likes?, instead of Who do you think Julianne likes? These rare L3 data in English were gathered from eight L1 Mongolian college students who already had working knowledge in L2 Russian. A cross-sectional oral-translation method was employed to elicit the data of L2 Russian and L3 English, which was further analyzed with the One-Sample Kolmogorov-Smirnov test to tell apart the group difference. According to the statistical analysis, the participants seemed to employ the L2 Russian grammar in the production of LD wh-questions in L3 English, but they selected the different wh-expletive what, not how as in L2 Russian. Since many other natural languages (Hungarian, German, Romani, among others) do employ what as the wh-expletive to mark their LD wh-questions, this study concludes that the participants somehow selected the linguistic option that is available in natural languages, but not available in their L1 Mongolian and L2 Russian
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