Coronagraphic Low Order Wave Front Sensor : post-processing sensitivity enhancer for high performance coronagraphs

Detection and characterization of exoplanets by direct imaging requires a coronagraph designed to deliver high contrast at small angular separation. To achieve this, an accurate control of low order aberrations, such as pointing and focus errors, is essential to optimize coronagraphic rejection and avoid the possible confusion between exoplanet light and coronagraphic leaks in the science image. Simulations and laboratory prototyping have shown that a Coronagraphic Low Order Wave-Front Sensor (CLOWFS), using a single defocused image of a reflective focal plane ring, can be used to control tip-tilt to an accuracy of 10^{-3} lambda/D. This paper demonstrates that the data acquired by CLOWFS can also be used in post-processing to calibrate residual coronagraphic leaks from the science image. Using both the CLOWFS camera and the science camera in the system, we quantify the accuracy of the method and its ability to successfully remove light due to low order errors from the science image. We also report the implementation and performance of the CLOWFS on the Subaru Coronagraphic Extreme AO (SCExAO) system and its expected on-sky performance. In the laboratory, with a level of disturbance similar to what is encountered in a post Adaptive Optics beam, CLOWFS post-processing has achieved speckle calibration to 1/300 of the raw speckle level. This is about 40 times better than could be done with an idealized PSF subtraction that does not rely on CLOWFS.Comment: 10 pages, 7 figures, accepted for publication in PAS

The subaru coronagraphic extreme AO (SCExAO) system: Wavefront control and detection of exoplanets with coherent light modulation in the focal plane

The Subaru Coronagraphic Extreme-AO (SCExAO) system is designed for high contrast coronagraphic imaging at small angular separations, and is scheduled to see first light on the Subam Telescope in early 2011. The wavefront control architecture for SCExAO is optimized for scattered light control and calibration at small angular separations, and is described in this paper. Key subsystems for the SCExAO wavefront control architecture have been successfully demonstrated, and we report results from these tests and discuss their role in the SCExAO system. Among these subsystems, a technique which can calibrate and remove static and slow speckles which traditionally limit high contrast detections is discussed. A visible light lab prototype system at Subam Telescope recently demonstrated speckle halo reduction to 2e-7 contrast within 2 2λ/D, and removal of static coherent speckles to 3e-9 contrast

The Subaru Coronographic Extreme AO (SCExAO) system: Implementation and performances of the Coronographic Low Order WaveFront Sensor

The Subaru Coronagraphic Extreme AO project (SCExAO) is a high performance coronagraph designed to deliver high contrast at small angular separation. For the detection of structures near the diffraction limit, an accurate control of low order wavefront aberrations - tip-tilt and focus - is essential as these aberrations create light leaks that are the source of confusion in the final science image. To address this major difficulty, we have equipped SCExAO with a specially designed Coronagraphic Low Order WaveFront Sensor (CLOWFS) using defocused images of a reflective ring located in the focal plane, that can track tip-tilt errors as small as 10-3?/D. CLOWFS was originally designed to drive actuators in a closed-loop. Here, we show that it can also be used in post-processing to efficiently subtract the tip-tilt induced coronagraphic leaks in the final science image

The Subaru coronagraphic extreme AO (SCExAO) system: Visible imaging mode

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system is an instrument designed to be inserted between the Subaru AO188 system and the infrared HiCIAO camera in order to greatly improve the contrast in the very close (less than 0.5") neighbourhood of stars. Next to the infrared coronagraphic path, a visible scientific path, based on a EMCCD camera, has been implemented. Benefiting from both Adaptive Optics (AO) correction and new data processing techniques, it is a powerful tool for high angular resolution imaging and opens numerous new science opportunities. We propose here a new image processing algorithm, based on the selection of the best signal for each spatial frequency. A factor 2 to 3 in Strehl ratio is obtained compared to the AO long exposure time depending on the image processing algorithm used and the seeing conditions. The system is able to deliver diffraction limited images at 650 nm (17 mas FWHM).We also demonstrate that this approach offers significantly better results than the classical select, shift and add approach (lucky imaging)

Intracellular expression of toll-like receptor 4 in neuroblastoma cells and their unresponsiveness to lipopolysaccharide

BACKGROUND: Recently it has been reported that, toll-like receptors (TLRs) are expressed on a series of tumor cells, such as colon cancer, breast cancer, prostate cancer, melanoma and lung cancer. Although some cancer cells like melanoma cells are known to respond to lipopolysaccharide (LPS) via TLR4, not all cancer cells are positive for TLR4. There is little information on the expression and function of TLR4 in neuroblastoma cells. In this study, we investigated the expression of TLR4 in human neuroblastoma NB-1 cell line. METHODS: Expression and localization of TLR4 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometric analysis, respectively. Activation of nuclear factor (NF)-κB by LPS was detected by degradation of IκB-α and NF-κB luciferase assay. Activation and expression of mitogen-activated protein (MAP) kinase and interferon regulatory factor (IRF)-3 was detected by immunoblot analysis. RESULTS: Human NB-1 neuroblastoma cells expressed intracellular form of TLR4, but not the cell surface form. Further, NB-1 cells express CD14, MD2 and MyD88, which are required for LPS response. However, LPS did not significantly induce NF-κB activation in NB-1 cells although it slightly degraded IκB-α. NB-1 cells expressed no IRF-3, which plays a pivotal role on the MyD88-independent pathway of LPS signaling. Collectively, NB-1 cells are capable to avoid their response to LPS. CONCLUSION: Although human NB-1 neuroblastoma cells possessed all the molecules required for LPS response, they did not respond to LPS. It might be responsible for intracellular expression of TLR4 or lack of IRF-3

Tanaecia coelebs Corbet, 1941 (Insecta, Lepidoptera): proposed conservation of the specific name

Volume: 56Start Page: 177End Page: 17

A new subspecies of the genus Euthalia Hübner, 1819, from Vietnam (Lepidoptera, Nymphalidae)

Une nouvelle sous-espèce du genre Euthalia Hubner, 1819, du Vietnam (Lepidoptera, Nymphalidae). Une nouvelle sous-espèce d' Euthalia iva est décrite du nord et du centre Vietnam.A new taxon of nymphalid belonging to the genus Euthalia (Limbusa) is described from northern and central Vietnam.Monastyrskh Alexander-L., Nguyen Thi Hong, Yokochi Takashi. A new subspecies of the genus Euthalia Hübner, 1819, from Vietnam (Lepidoptera, Nymphalidae). In: Bulletin de la Société entomologique de France, volume 105 (2), juin 2000. pp. 209-212

A new subspecies of the genus Euthalia Hübner, 1819, from Vietnam (Lepidoptera, Nymphalidae)

Une nouvelle sous-espèce du genre Euthalia Hubner, 1819, du Vietnam (Lepidoptera, Nymphalidae). Une nouvelle sous-espèce d' Euthalia iva est décrite du nord et du centre Vietnam.A new taxon of nymphalid belonging to the genus Euthalia (Limbusa) is described from northern and central Vietnam.Monastyrskh Alexander-L., Nguyen Thi Hong, Yokochi Takashi. A new subspecies of the genus Euthalia Hübner, 1819, from Vietnam (Lepidoptera, Nymphalidae). In: Bulletin de la Société entomologique de France, volume 105 (2), juin 2000. pp. 209-212