Highly Sensitive, Non-cryogenic NIR High-resolution Spectrograph, WINERED

WINERED is a novel near-infrared (NIR) high-resolution spectrograph (HRS) that pursues the highest possible sensitivity to realize high-precision spectroscopy in the NIR as in the optical wavelength range. WINERED covers 0.9–1.35 μm (z, Y, and J-bands) with three modes (Wide mode and two Hires modes) at the maximum spectral resolutions of R = 28,000 and R = 70,000. For fulfilling the objective, WINERED is designed with an unprecedentedly high instrument throughput (up to 50% at maximum including the quantum efficiency of the array) that is three times or more than other existing optical/NIR HRSs. This is mainly realized by a combination of non-white pupil and no fiber-fed configuration in optical design, the moderate (optimized) wavelength coverage, and the high-throughput gratings. Another prominent feature of WINERED is “warm” instrument despite for infrared (IR) observations. Such non-cryogenic (no cold stop) IR instrument finally became possible with the combination of custom-made thermal-cut filter of 10−8 class, 1.7 μm cutoff HAWAII-2RG array, and a cold baffle reducing the direct thermal radiation to the IR array into the solid angle of f/2. The thermal background is suppressed below 0.1 photons pixel−1 s−1 even in the wide band of 0.9–1.35 μm under the environment of 290 K. WINERED had been installed to the 3.58 m New Technology Telescope at La Silla Observatory, ESO, since 2017. Even with the intermediate size telescope, WINERED was confirmed to provide a limiting magnitude (for SNR = 30 with 8 hr. integration time) of J = 16.4 mag for the Wide mode and J = 15.1 mag for the Hires mode, respectively, under the natural seeing conditions. These sensitivities are comparable to those for the existing NIR-HRSs attached to the 8–10 m class telescopes with AO. WINERED type spectrographs may become a critical not only for the currently on-going extremely large telescopes to reduce the developing cost and time but also for smaller telescopes to extend their lives with long programs.

Apolipoprotein B and oxLDL levels in plasma of patients with diabetes, cardiovascular disease, and COVID-19

Elevated levels of low-density lipoprotein (LDL-X) cholesterol, apolipoprotein B (ApoB), and especially oxidized LDL in plasma are associated with an increased risk of cardiovascular disease (CVD). The aim of the study was to determine the levels of ApoB and oxLDL in the blood of patients with diabetes mellitus (DM), CVD and COVID-19. ApoB and oxLDL were determined using enzyme-linked immunosorbent assay kits (Elabscience, USA). The measurements were performed at an optical wavelength of 450 nm. It was found that ApoB and oxLDL levels in the blood of patients with diabetes and, especially, with COVID-19 are substantially higher than in the blood of healthy people. Blood levels of ApoB and oxLDL are higher in patients with both COVID-19 and diabetes or CVD as com pared to patients with COVID-19 without comorbidities. Thus, the levels of ApoB and oxidized LDL may be the promising markers of severe COVID-19.

Retrieving exoplanet atmospheric parameters using random forest regression

Understanding of exoplanet atmospheres can be extracted from the transmission spectra using an important tool based on a retrieval technique. However, the traditional retrieval method (e.g. MCMC and nested sampling) consumes a lot of computational time. Therefore, this work aims to apply the random forest regression, one of the supervised machine learning technique, to retrieve exoplanet atmospheric parameters from the transmission spectra observed in the optical wavelength. We discovered that the random forest regressor had the best accuracy in predicting planetary radius ( R F i t 2 = 0.999) as well as acceptable accuracy in predicting planetary mass, temperature, and metallicity of planetary atmosphere. Our results suggested that the random forest regression consumes significantly less computing time while gives the predicted results equivalent to those of the nested sampling PLATON retrieval.

Constraints on Optical Emission of FAST-detected FRB 20181130B with GWAC Synchronized Observations

Multiwavelength simultaneous observations are essential to the constraints on the origin of fast radio bursts (FRBs). However, it is a significant observational challenge due to the nature of FRBs as transients with a radio millisecond duration, which occur randomly in the sky regardless of time and position. Here, we report the search for short-time fast optical bursts in the Ground-based Wide Angle Camera (GWAC) archived data associated with FRB 20181130B, which were detected by the Five-hundred-meter Aperture Spherical radio Telescope and recently reported. No new credible sources were detected in all single GWAC images with an exposure time of 10 s, including images with coverage of the expected arrival time in optical wavelength by taking the high dispersion measurements into account. Our results provide a limiting magnitude of 15.43 ± 0.04 mag in the R band, corresponding to a flux density of 1.66 Jy or 8.35 mag in AB system by assuming that the duration of the optical band is similar to that of the radio band of about 10 ms. This limiting magnitude makes the spectral index of α < 0.367 from optical to radio wavelength. The possible existence of longer-duration optical emission was also investigated with upper limits of 0.33 Jy (10.10 mag), 1.74 mJy (15.80 mag), and 0.16 mJy (18.39 mag) for the durations of 50 ms, 10 s, and 6060 s, respectively. This undetected scenario could be partially attributed to the shallow detection capability, as well as the high inferred distance of FRB 20181130B and the low fluence in radio wavelength. The future detectability of optical flashes associated with nearby and bright FRBs are also discussed in this paper.

Effects of COVID-19, diabetes mellitus, and cardiovascular diseases on insulin receptor substrate-1 amount in the blood plasma of patients

Insulin receptor substrate (IRS) is a key adapter protein mediating effects of insulin and insulin-like growth factors (IGF) in cells. IRS-1 is a member of the insulin receptor substrate family, which is associated with tumor initiation and progression. The aim of the study is to determine the level of IRS-1 in the blood of patients (n = 81) with diabetes mellitus and COVID-19. IRS-1 was determined with enzyme-linked immunosorbent assay (ELISA) (Elabscience, USA). The measurements were performed at an optical wavelength of 450 nm. The level of IRS-1 in the blood plasma of patients with COVID-19 was much (from 3.5 to more than 6 times) higher than that in the blood of healthy people. The IRS-1 amounts in COVID-19 patients with diabetes and diabetes + CVD were significantly higher than in patients with COVID-19 without concomitant diseases. The level of IRS-1 in blood plasma may be one of the promising markers of COVID-19.

Coupled InGaAs Quantum Dots for Electro-Optic Modulation

We investigated the growth of vertically coupled In0.75Ga0.25As quantum dots (QDs) by varying the GaAs spacer thickness (d). Vertically-aligned triple-layer QDs of uniform size and highest accumulated strain are formed with d = 5 nm. The electroluminescence (EL) characteristics for In0.75Ga0.25As QDs show an emission spectrum at optical wavelength (λ) of 1100−1300 nm. The EL spectra exhibit the highest optical gain at λ ~ 1200 nm, and the narrowest FWHM = 151 nm of the sample with d = 5 nm at injection current = 20 mA. Fabry–Perot measurements at λ = 1515 nm of TE and TM polarizations were carried out to investigate the electro-optic modulation for a single-mode ridge waveguide consisting of vertically-coupled triple-layer In0.75Ga0.25As QDs (d = 5 nm). The linear (r) and quadratic (s) electro-optic coefficients are r = 2.99 × 10−11 m/V and s = 4.10 × 10−17 m2/V2 for TE polarization, and r = 1.37 × 10−11 m/V and s = 3.2 × 10−17 m2/V2 for TM polarization, respectively. The results highlight the potential of TE/TM lightwave modulation by InGaAs QDs at photon energy below energy band resonance.

Biolayer Interferometry for DNA-Protein Interactions v1

Biolayer interferometry (BLI) is a widely utilized technique for determining the interaction dynamics between macromolecules. Most BLI instruments, such as the Octet RED96e used throughout this protocol, are completely automated and detect changes in the interference pattern of white light reflected off a biosensor tip. Biosensors are initially loaded with a stationary macromolecule, then introduced into a solution containing macromolecules of interest. Binding to the stationary molecules creates a change in optical wavelength that is recorded by the instrument in real-time. The majority of published BLI experiments assess protein-protein (such as antibody-substrate kinetics) or protein-small molecule (such as drug discovery) interactions. However, a less-appreciated assay for BLI analysis is DNA-protein interactions. In our laboratory, we have shown the practicality of using biotinylated-DNA probes to determine the binding kinetics of transcription factors to specific DNA sequences. The following protocol describes these steps, including the generation of biotinylated-DNA probes, the execution of the BLI experiment, and data analysis through GraphPad Prism.