1,403 research outputs found
Microlensing Detections of Planets in Binary Stellar Systems
We demonstrate that microlensing can be used for detecting planets in binary
stellar systems. This is possible because in the geometry of planetary binary
systems where the planet orbits one of the binary component and the other
binary star is located at a large distance, both planet and secondary companion
produce perturbations at a common region around the planet-hosting binary star
and thus the signatures of both planet and binary companion can be detected in
the light curves of high-magnification lensing events. We find that identifying
planets in binary systems is optimized when the secondary is located in a
certain range which depends on the type of the planet. The proposed method can
detect planets with masses down to one tenth of the Jupiter mass in binaries
with separations <~ 100 AU. These ranges of planet mass and binary separation
are not covered by other methods and thus microlensing would be able to make
the planetary binary sample richer.Comment: 5 pages, two figures in JPG forma
The Influence of the Second Harmonic in the Current-Phase Relation on the Voltage-Current Characteristic of high TC DC SQUID
A theory for the voltage-current characteristic in high TC DC SQUIDs, which
accounts for a second harmonic in the junction current-phase relation, is
developed. The comparison with experiment is performed. It is shown that if the
second harmonic is prevailed, the theory can explain the large deviations of
the experimental voltage modulation from theoretical predictions and computer
simulations based on conventional sinusoidal current-phase relation.Comment: Eq. 13 is correcte
PAF-Mediated MAPK Signaling Hyperactivation via LAMTOR3 Induces Pancreatic Tumorigenesis
SummaryDeregulation of mitogen-activated protein kinase (MAPK) signaling leads to development of pancreatic cancer. Although Ras-mutation-driven pancreatic tumorigenesis is well understood, the underlying mechanism of Ras-independent MAPK hyperactivation remains elusive. Here, we have identified a distinct function of PCNA-associated factor (PAF) in modulating MAPK signaling. PAF is overexpressed in pancreatic cancer and required for pancreatic cancer cell proliferation. In mouse models, PAF expression induced pancreatic intraepithelial neoplasia with expression of pancreatic cancer stem cell markers. PAF-induced ductal epithelial cell hyperproliferation was accompanied by extracellular signal-regulated kinase (ERK) phosphorylation independently of Ras or Raf mutations. Intriguingly, PAF transcriptionally activated the expression of late endosomal/lysosomal adaptor, MAPK and mTOR activator 3 (LAMTOR3), which hyperphosphorylates MEK and ERK and is necessary for pancreatic cancer cell proliferation. Our results reveal an unsuspected mechanism of mitogenic signaling activation via LAMTOR3 and suggest that PAF-induced MAPK hyperactivation contributes to pancreatic tumorigenesis
The Intrinsic Shapes of Low-Surface-Brightness Dwarf Irregular Galaxies and Comparison to Other Types of Dwarf Galaxies
In this paper, we measure the ellipticities of 30 LSB dI galaxies and compare
the ellipticity distribution with that of 80 dEs (Ryden & Terndrup 1994; Ryden
et al. 1998) and 62 BCDs (Sung et al. 1998). We find that the ellipticity
distribution of LSB dIs is very similar to that of BCDs, and marginally
different from that of dEs. We then determine the distribution of intrinsic
shapes of dI galaxies and compare to those of other type dwarf galaxies under
various assumptions. First, we assume that LSB dIs are either all oblate or all
prolate, and use non-parametric analysis to find the best-fitting distribution
of intrinsic shapes. With this assumption, we find that the scarcity of nearly
circular LSB dIs implies, at the 99% confidence level, that they cannot be a
population of randomly oriented oblate or prolate objects. Next, we assume that
dIs are triaxial, and use parametric analysis to find permissible distributions
of intrinsic shapes. We find that if the intrinsic axis ratios, and
, are distributed according to a Gaussian with means and
and a common standard deviation of , the best-fitting set of
parameters for LSB dIs is , and
the best fit for BCDs is , while
the best fit for dEs is . The dIs
and BCDs thus have a very similar shape distribution, given this triaxial
hypothesis, while the dEs peak at a somewhat more spherical shape. Our results
are consistent with an evolutionary scenario in which the three types of dwarf
galaxy have a close relation with each other.Comment: total 18 pages, 4 figures, and 3 Tables, submitted to Astrophysical
Journal on Mar 5 199
Engineering and systems level analysis of <i>Saccharomyces cerevisiae</i> for production of 3 hydroxypropionic acid via malonyl CoA reductase dependent pathway
Expression of MT-1 MMP, MMP2, MMP9 and TIMP2 mRNAs in Ductal Carcinoma in Situ and Invasive Ductal Carcinoma of the Breast
We investigated the expression of membrane type-1 (MT1)-MMP, MMP2, MMP9 and TIMP2 mRNAs and their roles in ductal carcinoma in situ (DCIS) and T1 and T2 invasive ductal carcinoma of the breast. We further compared these two types of carcinomas for differences in microvessel density, and expression of angiogenic factors and CD44std. MT1-MMP, MMP2, MMP9 and TIMP2 mRNA were expressed in both DCIS and invasive ductal carcinomas. Expression rates of MT1-MMP, MMP2, MMP9 and TIMP2 mRNAs were not statistically different between DCIS and invasive ductal carcinomas, nor did they differ statistically when grouped by tumor size, histologic grade or nuclear grade of invasive ductal carcinoma. Microvessel density and expression of VEGF and TGF-β1 were not statistically different between DCIS and invasive ductal carcinoma. CD44std expression was significantly increased in DCIS compared to invasive ductal carcinoma (p < 0.05) and it was also significantly increased in lower clinical stage, histologic grade and nuclear grade of invasive ductal carcinoma (p < 0.05). Axillary node metastasis was significantly correlated with MT1-MMP mRNA, VEGF and TGF-β1 expression (p < 0.05) and MT1-MMP mRNA was positively correlated with VEGF expression and TIMP2 mRNA (p < 0.05). In summary, patterns of MMP mRNA expression in DCIS and invasive ductal carcinoma suggest that the invasive potential of breast carcinoma is already achieved before morphologically overt invasive growth is observed. As MT1-MMP mRNA expression is significantly correlated with axillary nodal metastasis, it may be useful as a prognostic indicator of invasive ductal carcinoma. Considering the positive correlation of MT1-MMP mRNA and TIMP2mRNA expression, our finding supports a role for TIMP2 in tumor growth, as well as the utility of CD44std as a prognostic indicator of breast cancer
Reliability of Eye Tracking and Pupillometry Measures in Individuals with Fragile X Syndrome
Recent insight into the underlying molecular and cellular mechanisms of fragile X syndrome (FXS) has led to the proposal and development of new pharmaceutical treatment strategies, and the initiation of clinical trials aimed at correcting core symptoms of the developmental disorder. Consequently, there is an urgent and critical need for outcome measures that are valid for quantifying specific symptoms of FXS and that are consistent across time. We used eye tracking to evaluate test–retest reliability of gaze and pupillometry measures in individuals with FXS and we demonstrate that these measures are viable options for assessing treatment-specific outcomes related to a core behavioral feature of the disorder
Clinicopathologic characteristics of granulosa cell tumors of the ovary: a multicenter retrospective study
Littoral Cell Angioma (LCA) Associated with Liver Cirrhosis
A littoral cell angioma (LCA) is a rare benign vascular tumor of the spleen. A 60-year-old man, with multiple nodules in imaging study and liver cirrhosis graded as Child-Pugh classification class A, was transferred for splenomegaly. A thrombocytopenia was found on hematological evaluation. Because there was no evidence of hematological and visceral malignancy, a splenectomy was performed for a definitive diagnosis. The histological and immunohistochemical features of the splenic specimens were consistent with a LCA. After the splenectomy, the thrombocytopenia recovered to the normal platelet count. There has been no previous report of a LCA combined with liver cirrhosis. Herein, the first case of a LCA in Korea, diagnosed and treated by a splenectomy, is reported
Exercise Training Improves Age-Related Myocardial Metabolic Derangement: Proton Magnetic Resonance Spectroscopy Study in the Rat Model
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