The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter

The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 μm—the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7–1.6 μm spectral range with a resolving power of ∼20,000. NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the 2.2–4.4 μm range. MIR achieves a resolving power of >50,000. It has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere. The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7–17 μm with apodized resolution varying from 0.2 to 1.3 cm−1. TIRVIM is primarily dedicated to profiling temperature from the surface up to ∼60 km and to monitor aerosol abundance in nadir. TIRVIM also has a limb and solar occultation capability. The technical concept of the instrument, its accommodation on the spacecraft, the optical designs as well as some of the calibrations, and the expected performances for its three channels are described

Manipulations with early mouse embryos for generation of genetically modified animals

Recently, genome-editing technologies have  become more efficient and accessible. The discovery of nucleases for directional genome editing (CRISPR/Cas9, TALEN, ZFNs) significantly accelerated and simplified the production of mice with targeted gene editing in the genome. Until last time, the CRISPR/Cas9 system noticeably simplified the preparation of knockout or transgenic mice. CRISPR/Cas9 technology was successfully applied for gene knockout and knock-in, generation of large deletions or directed insertions in targeted genome regions in embryonic stem cells (ESCs).When injected into blastocysts, such  modified ESCs are able to generate chimeras producing gametes with an identical genotype with ESC. Thus, it can identify animals with modified genomes. More recently, CRISPR/Cas9 technology was successfully applied to mouse zygotes and the birth of genetic modified mice was observed, i. e., the time required for generating genome-modified animals decreased significantly. The CRISPR/Cas9 system allows making gene knockout, large deletions or directed insertions into the target region of the genome by cytoplasm or pronuclear microinjection into zygotes. In addition, this is faster and simpler than similar work with mouse ESCs. Meanwhile, methods of manipulation with early embryos and their transplantation to surrogate mothers may be somewhat tricky. Therefore, it is important to use modern technologies for directional genome editing and perfect mastery in the embryological technics. In this article, we describe the protocols of microinjection into the pronucleus or cytoplasm of zygotes and injection of embryonic stem cells into the blastocyst cavity. We also describe embryological methods, such as superovulation, preparation of early stage  embryos,  surgical operation, production of foster mice. In addition, we describe the assembly and necessary components for the isoflurane anesthetic apparatus and isoflurane anesthesia

Genome editing using CRISPR/ Cas9 system: a practical guide

Over the past few years, the CRISPR/Cas techniques have become a revolution in genome editing. Since the original paper on CRIPSR/Cas9 genome editing, researches have proposed numerous modifications of the key components of the CRISPR/Cas9 system to make it extremely efficient. Nowadays, CRISPR/Cas systems can be used not only to modify genomes, but also to control expression levels of defined genes, visualize loci of interest in the space of living cell nuclei, change methylation status of mammalian CpG sites, and to serve many other purposes. Due to an extremely high efficacy and ease of usage, the CRISPR/ Cas system has been employed in a large number of studies in various areas of biology and biotechnology. We have recently published a review describing various CRISPR/Cas systems, mechanisms of their functioning, and applications of the techniques in details. Despite the broad range of potential applications of CRISPR/Cas systems, they are mostly used for genome editing. And, however simple the system may be, there is a number of potential pitfalls on the way towards its use in CRISPR/Cas- naïve laboratory settings. In this article, we describe protocols of CRISPR/Cas9 system generation. We start with a short description of theoretical aspects underlying Cas9-mediated genome editing. Next, we describe a step-by-step protocol of guide RNA vector design and assembly, and several ways of qualitative and quantitative evaluations of the system. Finally, we report protocols of genome editing for modification of embryonic stem cells and zygotes

Eight exoplanet candidates in SAO survey

Here we present eight new candidates for exoplanets detected by the transit method at the Special Astrophysical Observatory of the Russian Academy of Sciences. Photometric observations were performed with a 50-cm robotic telescope during the second half of 2020. We detected transits with depths of $\Delta m = 0.056-0.173^m$ and periods $P = 18.8^h-8.3^d$ in the light curves of stars with magnitudes of $m = 14.3-18.8^m$. All considered stars are classified as dwarfs with radii of $R_* = 0.4-0.6 R_{sun}$ (with the uncertainty for one star up to $1.1 R_{sun}$). We estimated the candidate radii (all are greater than 1.4 times the Jovian radius), semi-major axes of their orbits ($0.012-0.035 AU$), and other orbital parameters by modelling. We report the light curves with transits for two stars obtained in 2022 based on individual observations.Comment: 16 pages, 14 figures, 3 table

Pneumatic device of the preload and dynamic loads balancing to reduce the intensity of thermal processes in the metal cutting process

Improved reliability of the technological system "machine-tool-instrument-detail" is an important current task. Backlashes and insufficient stiffness of technological system lead to intensive wear of the cutting tool, increasing the heat in the cutting zone. Due to high temperature in the thin surface layers of the workpiece and tool thermal processes may occur which are similar to release and can cause the structural changes of the material. The current article presents the final design of the device which has been developed to reduce the intensity of thermal processes in metal cutting

Doppler confirmation of TESS planet candidate TOI1408.01: grazing transit and likely eccentric orbit

We report an independent Doppler confirmation of the TESS planet candidate orbiting an F-type main sequence star TOI-1408 located 140 pc away. We present a set of radial velocities obtained with a high-resolution fiber-optic spectrograph FFOREST mounted at the SAO RAS 6-m telescope (BTA-6). Our self-consistent analysis of these Doppler data and TESS photometry suggests a grazing transit such that the planet obscures its host star by only a portion of the visible disc. Because of this degeneracy, the radius of TOI-1408.01 appears ill-determined with lower limit about $\sim$1 R$_{\rm Jup}$, significantly larger than in the current TESS solution. We also derive the planet mass of $1.69\pm0.20$~$M_{\rm Jup}$ and the orbital period $\sim4.425$ days, thus making this object a typical hot Jupiter, but with a significant orbital eccentricity of $0.259\pm0.026$. Our solution may suggest the planet is likely to experience a high tidal eccentricity migration at the stage of intense orbital rounding, or may indicate possible presence of other unseen companions in the system, yet to be detected.Comment: 5 pages, 3 figure

Vertical structure and size distributions of Martian aerosols from solar occultation measurements

Solar occultations performed with a spectrometer on board the Soviet spacecraft Phobos 2 (Blamont et al. 1991) provided data on the vertical structure of the Martian aerosols in the equatorial region (0[deg]-20[deg] N latitude) near the northern spring equinox (LS = 0[deg]-20[deg]). All measurements were made close to the evening terminator. Five clouds were detected above 45 km altitude and their vertical structure recorded at six wavelengths between 0.28 and 3.7 [mu]m. They have a small vertical extent (3-6 km) and a vertical optical depth less than 0.03. The thermal structure, as derived from saturated profiles of water vapor observed by our instrument in the infrared, does not allow the CO2 frost point to be reached at cloud altitude, strongly suggesting that cloud particles are formed of H2O ice. Under the assumption of spherical particles, a precise determination of their effective radius, which varies from cloud to cloud and with altitude, is obtained and ranges from 0.15 to 0.85 [mu]m; an estimate of the effective variance of the particle size distribution is ~ 0.2. The number density of cloud particles at the peak extinction level is ~1 cm-3. Dust was also observed and monitored at two wavelengths, 1.9 and 3.7 [mu]m, on nine different occasions. The top of the dust opaque layer, defined as the level above which the atmosphere becomes nearly transparent at the wavelengths of observation, is located near 25 km altitude, with variations smaller than +/-3 km from place to place. The scale height of dust at this altitude is 3-4 km. The effective radius of dust particles near the top of the opaque layer is 0.95 +/- 0.25 [mu]m and increases below with a vertical gradient of ~0.05 [mu]m km-1. Assuming that particles are levitated by eddy mixing, the eddy diffusion coefficient, K, is found to be ~106 cm2 sec-1 at 25 km and 105-106 cm2 sec-1 at 50 km using, respectively, dust and cloud observations. An effective variance of 0.25 (+/-50%) for the dust size distribution is obtained on the basis of a simple theoretical model for the observed vertical gradient of the effective radius of dust particles. Three clouds observed by Viking at midlatitude during the northern summer are reanalyzed. The analysis gives K [approximate] 106 cm2 sec-1 below 50 km altitude and at least 107 cm2 sec-1 above. Since the clouds seen from Phobos 2 are observed at twilight, which coincides with the diurnal maximum of the ambient temperature, they can be assumed to be in a steady state. If their thermodynamic state were to vary quickly during the day, our optical thickness at twilight would correspond to unrealistic values in earlier hours when the temperature is lower. Clouds are well fitted by theoretical profiles obtained assuming the steady state. An atmospheric temperature of 165-170 K at ~50 km is inferred. The negative temperature gradient above the cloud is large (1.5-2 K km-1). A parallel is established between these thin clouds and the polar mesospheric clouds observed on Earth. It is shown that upwelling in equatorial regions at equinox could be a significant factor in levitating cloud particles.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30061/1/0000431.pd