2,052 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
Local structures of polar wurtzites Zn_{1-x}Mg_{x}O studied by Raman and {67}Zn/{25}Mg NMR spectroscopies and by total neutron scattering
Local compositions and structures of Zn_{1-x}Mg_{x}O alloys have been
investigated by Raman and solid-state {67}Zn/{25}Mg nuclear magnetic resonance
(NMR) spectroscopies, and by neutron pair-distribution-function (PDF) analyses.
The E2(low) and E2(high) Raman modes of Zn_{1-x}Mg_{x}O display Gaussian- and
Lorentzian-type profiles, respectively. At higher Mg substitutions, both modes
become broader, while their peak positions shift in opposite directions. The
evolution of Raman spectra from Zn_{1-x}Mg_{x}O solid solutions are discussed
in terms of lattice deformation associated with the distinct coordination
preferences of Zn and Mg. Solid-state magic-angle-spinning (MAS) NMR studies
suggest that the local electronic environments of {67}Zn in ZnO are only weakly
modified by the 15% substitution of Mg for Zn. {25}Mg MAS spectra of
Zn_{0.85}Mg_{0.15}O show an unusual upfield shift, demonstrating the prominent
shielding ability of Zn in the nearby oxidic coordination sphere. Neutron PDF
analyses of Zn_{0.875}Mg_{0.125}O using a 2x2x1 supercell corresponding to
Zn_{7}MgO_{8} suggest that the mean local geometry of MgO_{4} fragments concurs
with previous density functional theory (DFT)-based structural relaxations of
hexagonal wurtzite MgO. MgO_{4} tetrahedra are markedly compressed along their
c-axes and are smaller in volume than ZnO_{4} units by ~6%. Mg atoms in
Zn_{1-x}Mg_{x}O have a shorter bond to the -axial oxygen atom than to the
three lateral oxygen atoms, which is distinct from the coordination of Zn. The
precise structure, both local and average, of Zn_{0.875}Mg_{0.125}O obtained
from time-of-flight total neutron scattering supports the view that
Mg-substitution in ZnO results in increased total spontaneous polarization.Comment: 12 pages, 14 figures, 2 table
New Spirometry Indices for Detecting Mild Airflow Obstruction.
The diagnosis of chronic obstructive pulmonary disease (COPD) relies on demonstration of airflow obstruction. Traditional spirometric indices miss a number of subjects with respiratory symptoms or structural lung disease on imaging. We hypothesized that utilizing all data points on the expiratory spirometry curves to assess their shape will improve detection of mild airflow obstruction and structural lung disease. We analyzed spirometry data of 8307 participants enrolled in the COPDGene study, and derived metrics of airflow obstruction based on the shape on the volume-time (Parameter D), and flow-volume curves (Transition Point and Transition Distance). We tested associations of these parameters with CT measures of lung disease, respiratory morbidity, and mortality using regression analyses. There were significant correlations between FEV1/FVC with Parameter D (râ=â-0.83; pâ<â0.001), Transition Point (râ=â0.69; pâ<â0.001), and Transition Distance (râ=â0.50; pâ<â0.001). All metrics had significant associations with emphysema, small airway disease, dyspnea, and respiratory-quality of life (pâ<â0.001). The highest quartile for Parameter D was independently associated with all-cause mortality (adjusted HR 3.22,95% CI 2.42-4.27; pâ<â0.001) but a substantial number of participants in the highest quartile were categorized as GOLD 0 and 1 by traditional criteria (1.8% and 33.7%). Parameter D identified an additional 9.5% of participants with mild or non-recognized disease as abnormal with greater burden of structural lung disease compared with controls. The data points on the flow-volume and volume-time curves can be used to derive indices of airflow obstruction that identify additional subjects with disease who are deemed to be normal by traditional criteria
Association between use of hydrochlorothiazide and nonmelanoma skin cancer: Common data model cohort study in Asian population
Although hydrochlorothiazide (HCTZ) has been suggested to increase skin cancer risk in white Westerners, there is scant evidence for the same in Asians. We analyzed the association between the use of hydrochlorothiazide and non-melanoma in the Asian population using the common data model.
METHODS: A retrospective multicenter observational study was conducted using a distributed research network to analyze the effect of HCTZ on skin cancer from 2004 to 2018. We performed Cox regression to evaluate the effects by comparing the use of HCTZ with other antihypertensive drugs. All analyses were re-evaluated using matched data using the propensity score matching (PSM). Then, the overall effects were evaluated by combining results with the meta-analysis.
RESULTS: Positive associations were observed in the use of HCTZ with high cumulative dose for non-melanoma skin cancer (NMSC) in univariate analysis prior to the use of PSM. Some negative associations were observed in the use of low and medium cumulative doses.
CONCLUSION: Although many findings in our study were inconclusive, there was a non-significant association of a dose-response pattern with estimates increasing in cumulative dose of HCTZ. In particular, a trend with a non-significant positive association was observed with the high cumulative dose of HCTZ
Super Helium-Rich Population and the Origin of Extreme Horizontal-Branch Stars in Globular Clusters
Recent observations for the color-magnitude diagrams (CMDs) of the massive
globular cluster Omega Centauri have shown that it has a striking double main
sequence (MS), with a minority population of bluer and fainter MS well
separated from a majority population of MS stars. Here we confirm, with the
most up-to-date Y2 isochrones, that this special feature can only be reproduced
by assuming a large variation (Delta Y = 0.15) of primordial helium abundance
among several distinct populations in this cluster. We further show that the
same helium enhancement required for this special feature on the MS can by
itself reproduce the extreme horizontal-branch (HB) stars observed in Omega
Cen, which are hotter than normal HB stars. Similarly, the complex features on
the HBs of other globular clusters, such as NGC 2808, are explained by large
internal variations of helium abundance. Supporting evidence for the
helium-rich population is also provided by the far-UV (FUV) observations of
extreme HB stars in these clusters, where the enhancement of helium can
naturally explain the observed fainter FUV luminosity for these stars. The
presence of super helium-rich populations in some globular clusters suggests
that the third parameter, other than metallicity and age, also influences CMD
morphology of these clusters.Comment: 4 pages, 4 figures, accepted for publication in the Astrophysical
Journal Letter
Unilateral Pulmonary Edema: A Rare Initial Presentation of Cardiogenic Shock due to Acute Myocardial Infarction
Cardiogenic unilateral pulmonary edema (UPE) is a rare clinical entity that is often misdiagnosed at first. Most cases of cardiogenic UPE occur in the right upper lobe and are caused by severe mitral regurgitation (MR). We present an unusual case of right-sided UPE in a patient with cardiogenic shock due to acute myocardial infarction (AMI) without severe MR. The patient was successfully treated by percutaneous coronary intervention and medical therapy for heart failure. Follow-up chest Radiography showed complete resolution of the UPE. This case reminds us that AMI can present as UPE even in patients without severe MR or any preexisting pulmonary disease affecting the vasculature or parenchyma of the lung
Local structure evolution in polycrystalline ZnMgO () studied by Raman and by synchrotron x-ray pair distribution analysis
The local structures of ZnMgO alloys have been studied by Raman
spectroscopy and by synchrotron x-ray pair distribution function (PDF)
analysis. Within the solid solution range () of
ZnMgO, the wurtzite framework is maintained with Mg homogeneously
distributed throughout the wurtzite lattice. The Raman line
of ZnMgO displays systematic changes in response to the evolution
of the crystal lattice upon the Mg-substitution. The red-shift and broadening
of the mode are explained by the expansion of hexagonal
-dimensions, and compositional disorder of Zn/Mg, respectively. Synchrotron
x-ray PDF analyses of ZnMgO reveal that the Mg atoms have a
slightly reduced wurtzite parameter and more regular tetrahedral bond
distances than the Zn atoms. For both Zn and Mg, the internal tetrahedral
geometries are independent of the alloy composition.Comment: 10 pages, 12 figures RevTe
Proteomic analysis of pregnancy-related proteins from pig uterus endometrium during pregnancy
Many important molecular events associated with implantation and development occur within the female reproductive tract, especially within the uterus endometrium, during pregnancy periods. The endometrium includes the mucosal lining of the uterus, which provides a suitable site for implantation and development of a fertilized egg and fetus. To date, the molecular cascades in the uterus endometrium during pregnancy periods in pigs have not been elucidated fully. In this study, we compared the functional regulated proteins in the endometrium during pregnancy periods with those in non-pregnant conditions and investigated changes in expression patterns during pregnancy (days 40, 70, and 93) using two-dimensional gel electrophoresis (2-DE) and western blotting. The functional regulated proteins were identified and discovered from differentially expressed proteins in the uterus endometrium during pregnancy. We discovered 820 protein spots in a proteomic analysis of uterus endometrium tissues with 2-DE gels. We identified 63 of the 98 proteins regulated differentially among non-pregnant and pregnant tissues (matched and unmatched spots). Interestingly, 10 of these 63 proteins are development-, cytoskeleton- and chaperon-related proteins such as transferrin, protein DJ-1, transgelin, galectin-1, septin 2, stathmin 1, cofilin 1, fascin 1, heat shock protein (HSP) 90ÎČ and HSP 27. The specific expression patterns of these proteins in the endometrium during pregnancy were confirmed by western blotting. Our results suggest that the expressions of these genes involved in endometrium function and endometrium development from early to late gestation are associated with the regulation of endometrium development for maintaining pregnancy
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