6,066 research outputs found

    Millimagnitude Optical Photometry for the Transiting Planetary Candidate OGLE-TR-109

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    We present precise V-band photometry for the low-amplitude transit candidate star OGLE-TR-109. This is an extreme case among the transiting candidates found by the OGLE group because of the early spectral type of the star (F0V), of the low transit amplitude (A_I=0.008 mag), and of the very short period (P=0.58909 days) of the orbiting companion. Using difference image photometry, we are able to achieve millimagnitude errors in the individual data points. One transit of this star is well defined in our light curve. This confirms the OGLE detection and rules out the possibility of a false positive. The measurement of this transit allows to refine the transit amplitude (A_V=0.006 +/- 0.001 mag), and the ephemerides for this interesting system, as well as the radius of the possible orbiting companion (R_P=0.90 +/- 0.09 ~R_J), and the inclination of the orbit (i=77 +/- 5 deg). Two other transits observed at lower S/N confirm the period of this system measured by OGLE. There is no evidence for a blend of the F-type main sequence star with a redder eclipsing binary, or for secondary transits in the present observations. The absence of ellipsoidal modulation in the light curve of the primary rules out a low mass star companion or brown dwarf with M>14 +/- 8 M_J. The remaining possibilities for OGLE-TR-109 are a blend between the F-type star and a binary with a bluer primary star, or a new transiting extrasolar planet.Comment: 24 pages (including figures) submitteed to ApJ, Accepted. 1 replacement (updated references

    Synthesis and Characterization of functional ceramic materials at the nano- and microscale with enhanced properties

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    Semiconductor nanoparticles (NPs) and nanowires (NWs) of doped ZnO system have been synthesised at low temperature (190 °C) by a novel Polyol-Mediated Thermolysis (PMT) process and Vapour-Solid (VS) reaction. Ce/Ru doped ZnO NPs with different molar content (1-3--5-10%) have been synthesised by both experimental processes. The crystallite size, morphology, specific surface area and band gap have been evaluated. Also, the structural and functional characteristics were carried out by X-ray diffraction technique (XRD), high resolution transmission electron microscopy (HRTEM), Brunauer, Emmett and Teller (BET) method, UV-Vis diffuse reflectance spectra (DRS), UV-Vis spectroscopy and photoluminescence measurements (PL). Also, the photocatalytic activities of ZnO nanoparticles were evaluated by removal rate of methyleneblue (MB) under UV irradiation (365 nm) at RT. XRD patterns revealed a hexagonal ZnO wurtzite-type crystalline structure with a preferred orientation of(101) plane. Any secondary phases have been identified such as Ce02, Ce203, ee, Ru02, Ru304, Ru. HRTEM showed NPs in shape from spherical/ellipsoidal to hexagonal, that does not change significantly with the increasing of precursor solution concentration and kind of dopant element in the samples obtained from PMTprocess. The size of NPs was observed in the range from 16 to 23 run. Using the Kubelka-Munk treatment on the diffuse reflectance spectra, the direct band energy has been estimated at <3.0 eV in the Ru-doped samples. The PL spectra mainly consist of four emission bands: (i) a strong UV emission band, (ii) a weak blue band, (iii) a blue-green band and (iv) a green-yellow band, respectively. The reported results showed the photocatalytic efficiency of doped ZnO nanoparticles was always enhanced

    Egg Intake during Carbohydrate Restriction Alters Peripheral Blood Mononuclear Cell Inflammation and Cholesterol Homeostasis in Metabolic Syndrome

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    Egg yolk contains bioactive components that improve plasma inflammatory markers and HDL profiles in metabolic syndrome (MetS) under carbohydrate restriction. We further sought to determine whether egg yolk intake affects peripheral blood mononuclear cell (PBMC) inflammation and cholesterol homeostasis in MetS, as HDL and its associated lipid transporter ATP-binding cassette transporter A1 (ABCA1) reduce the inflammatory potential of leukocytes through modulation of cellular cholesterol content and distribution. Thirty-seven men and women classified with MetS consumed a moderate carbohydrate-restricted diet (25%–30% of energy) for 12 weeks, in addition to consuming either three whole eggs per day (EGG) or the equivalent amount of yolk-free egg substitute (SUB). Interestingly, lipopolysaccharide-induced PBMC IL-1ÎČ and TNFα secretion increased from baseline to week 12 in the SUB group only, despite increases in PBMC toll-like receptor 4 (TLR4) mRNA expression in the EGG group. Compared to baseline, ABCA1 and 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase mRNA expression increased by week 12 in the EGG group only, whereas changes in PBMC total cholesterol positively correlated with changes in lipid raft content. Together, these findings suggest that intake of whole eggs during carbohydrate restriction alters PBMC inflammation and cholesterol homeostasis in MetS
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