A5063472317- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Optical Systems and Laser Technology
- EEG and Brain-Computer Interfaces
- CCD and CMOS Imaging Sensors
- Astrophysics and Star Formation Studies
- Tactile and Sensory Interactions
- Neuropeptides and Animal Physiology
- Advanced optical system design
- Robot Manipulation and Learning
- Peptidase Inhibition and Analysis
- Astronomical Observations and Instrumentation
- Calibration and Measurement Techniques
- Geophysics and Gravity Measurements
- Advanced Optical Sensing Technologies
- Blind Source Separation Techniques
- Emotion and Mood Recognition
- Industrial Automation and Control Systems
- Helicobacter pylori-related gastroenterology studies
- Hydrological Forecasting Using AI
- Multi-Criteria Decision Making
- Wireless Body Area Networks
- Antenna Design and Analysis
- Optical Coherence Tomography Applications
NSF’s NOIRLab
2024
University of California, San Diego
2024
Gemini North Observatory
2024
Herzberg Institute of Astrophysics
2020-2022
National Research Council Canada
2022
University of California, Los Angeles
2022
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2013-2021
Université Paris Cité
2014-2021
Centre National de la Recherche Scientifique
2014-2021
Université Paris Sciences et Lettres
2013-2021
The recent identification in Heloderma horridum venom of exendin-3, a new member the glucagon superfamily that acts as pancreatic secretagogue, prompted search for similar peptide suspectum venom. An amino acid sequencing assay peptides containing an amino-terminal histidine residue (His1) was used to isolate 39-amino peptide, exendin-4, from H. Exendin-4 differs exendin-3 by two substitutions, Gly2-Glu3 place Ser2-Asp3, but is otherwise identical. structural differences make exendin-4...
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is a multipurpose high-contrast imaging platform designed for the discovery and detailed characterization of exoplanetary systems serves as testbed technologies ELTs. It multi-band which makes use light from 600 to 2500nm allowing coronagraphic direct exoplanet inner 3 lambda/D stellar host. Wavefront sensing control are key operation SCExAO. A partial correction low-order modes provided by Subaru's facility adaptive optics...
To find mammalian analogues of exendin-4, a peptide from Helodermatidae venoms that interacts with newly discovered exendin receptors on dispersed acini guinea pig pancreas, we examined the actions recent additions to vasoactive intestinal peptide/secretin/glucagon family regulatory peptides. In every respect tested, truncated form glucagon-like peptide-1, GLP-1(7-36)NH2, mimicked exendin-4. Like GLP-1(7-36)NH2 caused an increase in acinar cAMP without stimulating amylase release....
Magnetic resonance imaging (MRI) is a technique which used for the evaluation of brain tumor in medical science. In this paper, methodology to study and classify image de-noising filters such as Median filter, Adaptive Averaging Un-sharp masking filter Gaussian remove additive noises present MRI images i.e. Gaussian, Salt & pepper noise speckle noise. The performance all considered strategies compared using PSNR MSE. A novel idea proposed successful identification normalized histogram...
This paper presents the first on-sky demonstration of speckle nulling, which was achieved at Subaru Telescope in context Coronagraphic Extreme Adaptive Optics (SCExAO) Project. Despite absence a high-order high-bandwidth closed-loop AO system, observations conducted with SCExAO show that even poor-to-moderate observing conditions, nulling can be used to suppress static and slow speckles presence brighter dynamic halo, suggesting more advanced high-contrast imaging algorithms developed...
High performance coronagraphic imaging of faint structures around bright stars at small angular separations requires fine control tip, tilt, and other low order aberrations. When such errors occur upstream a coronagraph they result in starlight leakage, which reduces the dynamic range instrument. This issue has been previously addressed for occulting coronagraphs by sensing before or focal plane. One solution, wave-front sensor (CLOWFS), uses partially reflective plane mask to measure...
We present $H$-band scattered light imaging of a bright debris disk around the A0 star HD 36546 obtained from Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system with data recorded by HiCIAO camera using vector vortex coronagraph. SCExAO traces $r$ $\sim$ 0.3" to 1" (34--114 au). The is oriented in near east-west direction (PA 75$^{o}$), inclined $i$ 70--75$^{o}$ and strongly forward-scattering ($g$ $>$ 0.5). It an extended rather than sharp ring; second, diffuse dust population...
The ability to characterize exoplanets by spectroscopy of their atmospheres requires direct imaging techniques isolate planet signal from the bright stellar glare. One limitations with detection exoplanets, either ground- or space-based coronagraphs, is pointing errors and other low-order wavefront aberrations. coronagraphic sensitivity at diffraction limit therefore depends on how well aberrations upstream focal plane mask are corrected. To prevent starlight leakage inner working angle a...
Context. Fewer than 1% of all exoplanets detected to date have been characterized on the basis spectroscopic observations their atmosphere. Unlike indirect methods, high-contrast imaging offers access atmospheric signatures by separating light a faint off-axis source from that its parent star. Forthcoming space facilities, such as WFIRST/LUVOIR/HabEX, are expected use coronagraphic instruments capable and spectroscopy in order understand physical properties remote worlds. The primary...
SCExAO is the premier high-contrast imaging platform for Subaru Telescope. It offers high Strehl ratios at near-IR wavelengths (y-K band) with stable pointing and coronagraphs extremely small inner working angles, optimized faint companions very close to host. In visible, it has several interferometric imagers which offer polarimetric spectroscopic capabilities. A recent addition RHEA spectrograph enabling spatially resolved resolution spectroscopy of surfaces giant stars, example. New...
High-order wavefront correction is not only beneficial for high-contrast imaging, but also spectroscopy. The size of a spectrograph can be decoupled from the telescope aperture by moving to diffraction limit which has strong implications ELT based instrument design. Here we present construction and characterization an extremely efficient single-mode fiber feed behind extreme adaptive optics system (SCExAO). We show that this indeed utilized great success photonic-based spectrographs. metrics...
The sense of touch is an extremely important sensory system in the human body which helps to understand object shape, texture, hardness world around us. Incorporating artificial haptic systems rehabilitative aids and various other computer interfaces a thrust area research presently. This paper presents novel approach shape recognition classification from tactile pressure images by touching surface real life objects. Here four objects (viz. planar surface, with one edge, cuboid i.e. two...
Vibrations are a key source of image degradation in ground-based instrumentation, especially for high-contrast imaging instruments. reduce the quality correction provided by adaptive optics system, blurring science image, and reducing sensitivity most modules. We studied vibrations using Subaru coronagraphic extreme instrument at Telescope as it is vibration-sensitive system installed on telescope. observed all targets, usually low frequency, below 10 Hz. Using accelerometers telescope, we...
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument, under development for the Telescope, has currently fastest on-sky wavefront control loop, with a pyramid sensor running at 3.5 kHz. But even that speed, we are still limited by low-frequency vibrations. current main limitation was found to be vibrations attributed mainly rotation of telescope. Using fast sensors, cameras and accelerometers, managed identify origin most degrading our performance. Low-frequency coming from...
The vector vortex is a coronagraphic imaging mode of the recently commissioned Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) platform on 8 m Telescope. This multi-purpose high-contrast visible and near-infrared (R- to K-band) instrument not only intended serve as VLT-class "planet-imager" in northern hemisphere, but also operate technology demonstration testbed ahead ELTs-era, with particular emphasis small inner-working angle (IWA) capabilities. given priority small-IWA led early...
Context. Spectroscopy of exoplanets is very challenging because the high star-planet contrast. A technical difficulty in design imaging instruments noncommon path aberrations (NCPAs) between adaptive optics (AO) sensing and science camera, which induce planet-resembling stellar speckles coronagraphic images. In an observing sequence several long exposures, quickly evolving NCPAs average out leave behind AO halo that adds photon noise to planet detection. Static NCPA can be calibrated a...
We will provide a summary review of the capabilities and overall status Planetary Systems Instrument (PSI), second-generation instrumentation suite for TMT. The PSI concept follows modular design operates from optical to thermal infrared wavelengths, combining high-order AO correction with coronagraphs, imaging low-resolution integral-field spectroscopy, fiber-coupled spectrometers. an overview recent development, including description key requirements, performance simulation, front-end...
To determine whether prostaglandin exerts a direct action on individual gastric epithelial cells that protects them from ethanol-induced injury, dispersed chief guinea pig stomach were pretreated with 16,16-dimethyl-prostaglandin E2 (dmPGE2) or placebo before incubation ethanol control. Cell injury was assessed in terms of exclusion Fast Green dye, release lactate dehydrogenase, alterations ultrastructure, and pepsinogen secretion stimulated by variety secretagogues. Of 60 +/- 2% stained if...
Detecting faint companions in close proximity to stars is one of the major goals current/planned ground- and space-based high-contrast imaging instruments. High-performance coronagraphs can suppress diffraction features gain access at small angular separation. However, uncontrolled pointing errors degrade coronagraphic performance by leaking starlight around focal-plane mask, preventing detection separations. A Lyot-stop low-order wavefront sensor (LLOWFS) was therefore introduced calibrate...