Synthesis of 2-Difluoroethylated 2H-1,3-Benzoxazines via Proton-Mediated Ring Opening/Interrupted Ritter Reaction of 1,1-Difluorocyclopropanes.

2-(1,1-Difluoroethyl)-2H-1,3-benzoxazines were synthesized by (i) the regioselective ring opening of 1,1-difluorocyclopropanes bearing an aryloxy group and (ii) the Ritter reaction followed by a Friedel-Crafts-type ring closure. When 2-aryloxy-1,1-difluorocyclopropanes were treated with triflic acid, the C-C bond distal to the CF2 moiety was cleaved regioselectively via protonation to generate the corresponding oxocarbenium ions. These intermediates readily underwent nucleophilic attack by nitriles, followed by a carbocationic cyclization to afford the 2-difluoroethylated benzoxazines.

Twenty-four-hour continuous and remote monitoring of respiratory rate using a medical radar system for the early detection of pneumonia in symptomatic elderly bedridden hospitalized patients.

Respiratory rate is often measured manually and discontinuously by counting of chest wall movements in routine clinical practice. We introduce a novel approach to investigate respiration dynamics using a noncontact medical radar system for identifying patient at risk of infection. The system enables early detection of pneumonia in bedridden hospitalized patients.

High-Contrast Imaging of Intermediate-Mass Giants with Long-Term Radial Velocity Trends.

A radial velocity (RV) survey for intermediate-mass giants has been operated for over a decade at Okayama Astrophysical Observatory (OAO). The OAO survey has revealed that some giants show long-term linear RV accelerations (RV trends), indicating the presence of outer companions. Direct imaging observations can help clarify what objects generate these RV trends. We present the results of high-contrast imaging observations of six intermediate-mass giants with long-term RV trends using the Subaru Telescope and HiCIAO camera. We detected co-moving companions to γ Hya B ( 0.61 - 0.14 + 0.12 M ⊙ ) , HD 5608 B (0.10 ± 0.01M ⊙), and HD 109272 B (0.28 ± 0.06M ⊙). For the remaining targets(ι Dra, 18 Del, and HD 14067) we exclude companions more massive than 30-60 M Jup at projected separations of 1''-7''. We examine whether these directly imaged companions or unidentified long-period companions can account for the RV trends observed around the six giants. We find that the Kozai mechanism can explain the high eccentricity of the inner planets ι Dra b, HD 5608 b, and HD 14067 b.

Near-infrared imaging polarimetry of LkCa 15: A possible warped inner disk.

We present high-contrast H-band polarized intensity images of the transitional disk around the young solar-like star LkCa 15. By utilizing Subaru/HiCIAO for polarimetric differential imaging, the angular resolution and the inner working angle reach 0.07 and r = 0″.1, respectively. We obtained a clearly resolved gap (width ≲ 27 au) at ~48 au from the central star. This gap is consistent with images reported in previous studies. We also confirmed the existence of a bright inner disk with a misaligned position angle of 13° ±4° with respect to that of the outer disk, i.e., the inner disk is possibly warped. The large gap and the warped inner disk both point to the existence of a multiple planetary system with a mass of ≲ 1 M Jup.

Real-time point-diffraction interferometer and its analytical formulation.

We propose a novel wavefront sensor and study its performance with an analytical formulation. The sensor has a polarizing point-diffraction beam splitter. Using transmitted and reflected beams, we can build a real-time point-diffraction interferometer with high precision and efficiency. Our analytical studies reveal that wavefront errors might be measured incorrectly and that less precise estimates of wavefronts appear as the pinhole radius Rpin is increased. An investigation of propagating uncertainties shows that the wavefront measurement can be calibrated by estimating the pinhole effects and the polarizing properties with a precision of a few percent. Based on these studies, Rpin should be smaller than half of the Airy disk for better performance.

Measurement of complex amplitude with a point-diffraction interferometer.

We propose a pupil-plane wavefront sensor to measure instantaneous phase and amplitude aberrations, developing the configuration of the point-diffraction interferometer proposed by Imada et al. [Appl. Opt. (2015), accepted]. The previous configuration allows us to instantaneously acquire four phase-shifted interferograms, from which cosine and sine functions of the relative phase difference between the test and reference beams can be derived. Here, because the wavefront phase can be reconstructed from only its sine function when the aberration of the input beam is smaller than half that of the sensing wavelength, we directly measure the intensities of the test and the reference beams instead of two of the four interferograms. Using this proposed configuration enables reconstruction of not only the wavefront phase but also its amplitude. The conceptual design of the proposed sensor is described, and its performance is evaluated compared with the original point-diffraction interferometer through numerical simulations.