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Common protein-coding variants influence the racing phenotype in galloping racehorse breeds
No full textSelection for system-wide morphological, physiological, and metabolic adaptations has led to extreme athletic phenotypes among geographically diverse horse breeds. Here, we identify genes contributing to exercise adaptation in racehorses by applying genomics approaches for racing performance, an end-point athletic phenotype. Using an integrative genomics strategy to first combine population genomics results with skeletal muscle exercise and training transcriptomic data, followed by whole-genome resequencing of Asian horses, we identify protein-coding variants in genes of interest in galloping racehorse breeds (Arabian, Mongolian and Thoroughbred). A core set of genes, G6PC2, HDAC9, KTN1, MYLK2, NTM, SLC16A1 and SYNDIG1, with central roles in muscle, metabolism, and neurobiology, are key drivers of the racing phenotype. Although racing potential is a multifactorial trait, the genomic architecture shaping the common athletic phenotype in horse populations bred for racing provides evidence for the influence of protein-coding variants in fundamental exercise-relevant genes. Variation in these genes may therefore be exploited for genetic improvement of horse populations towards specific types of racing
BASS XXXIX: Swift-BAT AGN with changing-look optical spectra
No full textChanging-look (CL) AGN are unique probes of accretion onto supermassive black holes (SMBHs), especially when simultaneous observations in complementary wavebands allow investigations into the properties of their accretion flows. We present the results of a search for CL behaviour in 412 Swift-BAT detected AGN with multiple epochs of optical spectroscopy from the BAT AGN Spectroscopic Survey (BASS). 125 of these AGN also have 14–195 keV ultra-hard X-ray light curves from Swift-BAT which are contemporaneous with the epochs of optical spectroscopy. Eight CL events are presented for the first time, where the appearance or disappearance of broad Balmer line emission leads to a change in the observed Seyfert type classification. Combining with known events from the literature, 21 AGN from BASS are now known to display CL behaviour. Nine CL events have 14–195 keV data available, and five of these CL events can be associated with significant changes in their 14–195 keV flux from BAT. The ultra-hard X-ray flux is less affected by obscuration and so these changes in the 14–195 keV band suggest that the majority of our CL events are not due to changes in line-of-sight obscuration. We derive a CL rate of 0.7–6.2 per cent on 10–25 yr time-scales, and show that many transitions happen within at most a few years. Our results motivate further multiwavelength observations with higher cadence to better understand the variability physics of accretion onto SMBHs
Water activation and splitting by single anionic iridium atoms
No full textMass spectrometric analysis of anionic products that result from interacting Ir− with H2O shows the efficient generation of [Ir(H₂O)]⁻ complexes and IrO⁻ molecular anions. Anion photoelectron spectra of [Ir(H₂O)]⁻, formed under various source conditions, exhibit spectral features that are due to three different forms of the complex: the solvated anion–molecule complex, Ir⁻(H₂O), as well as the intermediates, [H–Ir–OH]⁻ and [H₂–Ir–O]⁻, where one and two O–H bonds have been broken, respectively. The measured and calculated vertical detachment energy values are in good agreement and, thus, support identification of all three types of isomers. The calculated reaction pathway shows that the overall reaction Ir⁻ + H₂O → IrO⁻ + H₂ is exothermic. Two minimum energy crossing points were found, which shuttle intermediates and products between singlet and triplet potential surfaces. This study presents the first example of water activation and splitting by single Ir⁻ anions
Lifts of Borel actions on quotient spaces
No full textGiven a countable Borel equivalence relation E and a countable group G, we study the problem of when a Borel action of G on X/E can be lifted to a Borel action of G on X
Enantioselective Synthesis of N-Benzylic Heterocycles by Ni/Photoredox Dual Catalysis
No full textAn asymmetric cross-coupling of α-N-heterocyclic trifluoroborates with aryl bromides using Ni/photoredox dual catalysis has been developed. This C(sp²)–C(sp³) cross-coupling provides access to pharmaceutically relevant chiral N-benzylic heterocycles in good to excellent enantioselectivity when bioxazolines (BiOX) are used as the chiral ligand. High-throughput experimentation significantly streamlined reaction development by identifying BiOX ligands for further investigation and by allowing for rapid optimization of conditions for new trifluoroborate salts
Spectroscopic and Kinetic Studies of the ClSO Radical from Cl₂SO Photolysis
No full textThionyl chloride (Cl₂SO) serves as a common Cl atom source in widespread applications of chlorine chemistry though little is known about the reactivity and spectroscopy of the ClSO radical after a Cl–S bond cleavage. We performed a Pulsed Laser Photolysis experiment to detect ClSO from Cl₂SO photolysis at 248 nm in a gas-flow reactor by time-resolved UV–vis transient absorption spectroscopy. A few chemical tests, using I₂ and NO₂, suggested the structured absorption band between 260 and 320 nm belonged to ClSO radical and that the termolecular ClSO + Cl + M → Cl₂SO association reaction occurred. From EOMIP-CCSD/ano-pVQZ calculations, the ClSO band was assigned to the 1²A″ ← X²A″ transition involving the π* ← π transition of the SO bond and the vibrational progression to the SO stretching mode of the 1²A″ state, with a maximum cross-section = (2.0 ± 0.5) × 10⁻¹⁸ cm² near 286 nm (1σ uncertainty) and an average spacing of vibrational structure of 658 cm⁻¹. The rapid decay of the ClSO signal monitored near 303 nm could be fit to a second-order kinetic model over 10–90 Torr, which yields an effective bimolecular rate coefficient k_(Cl+ClSO) = (1.48 ± 0.42) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ at 292 K and 90 Torr (1σ uncertainty). This fast recombination reaction suggests that Cl-containing SOx species might act as significant Cl atom reservoirs in sulfur oxide-rich environments such as Venus’ atmosphere. Moreover, the reported UV spectrum provides a new means for monitoring the ClSO radicals
NuSTAR Spectral Analysis beyond 79 keV with Stray Light
No full textDue to the structure of the NuSTAR telescope, photons at a large off axis (>1°) can reach the detectors directly (stray light), without passing through the instrument optics. At these off-axis angles NuSTAR essentially turns into a collimated instrument and the spectrum can extend to energies above the Pt K edge (79 keV) of the multilayers, which limits the effective area bandpass of the optics. We present the first scientific spectral analysis beyond 79 keV using a Cygnus X-1 observation in StrayCats: the catalog of stray light observations. This serendipitous stray light observation occurred simultaneously with an INTEGRAL observation. When the spectra are modeled together in the 30–120 keV energy band, we find that the NuSTAR stray light flux is well calibrated and constrained to be consistent with the INTEGRAL flux at the 90% confidence level. Furthermore, we explain how to treat the background of the stray light spectral analysis, which is especially important at high energies
Spectroscopic Mapping of Io's Surface with HST/STIS: SO₂ Frost, Sulfur Allotropes, and Large-scale Compositional Patterns
No full textIo's intense volcanic activity results in one of the most colorful surfaces in the solar system. Ultraviolet and visible-wavelength observations of Io are critical to uncovering the chemistry behind its volcanic hues. Here, we present global, spatially resolved ultraviolet-visible spectra of Io from the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, which bridge the gap between previous highly resolved imagery and disk-integrated spectroscopy, to provide an unprecedented combination of spatial and spectral detail. We use this comprehensive data set to investigate spectral endmembers, map observed spectral features associated with SO₂ frost and other sulfur species, and explore possible compositions in the context of Io surface processes. In agreement with past observations, our results are consistent with extensive equatorial SO₂ frost deposits that are stable over multidecade timescales, widespread sulfur-rich plains surrounding the SO₂ deposits, and the enrichment of Pele's pyroclastic ring and the high-latitude regions in metastable short-chain sulfur allotropes
Prognostic potential of METTL3 expression in patients with gastric cancer
No full textMethyltransferase‑like 3 (METTL3) is a crucial component of the m6A methyltransferase complex, which serves pivotal roles in tumor progression. The present study investigated the prognostic significance of METTL3 expression in gastric cancer (GC). The expression levels of METTL3 were assessed by immunohistochemistry in formalin‑fixed paraffin‑embedded (FFPE) tissue specimens from 158 patients with GC. Propensity score matching (PSM) analysis was performed to clarify its prognostic potential. METTL3 gene expression was also investigated in fresh frozen specimens from another independent cohort of 57 patients with GC to establish its clinical relevance. Knockdown of METTL3 by small interfering RNA transfection was performed to evaluate its function in vitro. METTL3 expression was significantly higher in cancerous tissues compared with in corresponding normal mucosa (P<0.0001), and high METTL3 expression was an independent prognostic factor for overall and disease‑free survival in the FFPE cohort of patients with GC. PSM analysis revealed that elevated METTL3 expression was significantly associated with poor survival outcomes, which was subsequently validated in another cohort of fresh frozen specimens. Knockdown of METTL3 inhibited proliferation, invasion, migration and anoikis resistance in GC cells. In conclusion, METTL3 expression may be used as a clinically feasible prognostic marker and could serve as a potential therapeutic target in patients with GC
Morphodynamic Modeling of River-Dominated Deltas: A Review and Future Perspectives
No full textRiver-dominated deltas on Earth are composed of diverse shapes and patterns, ranging from small-scale bifurcations that create channel networks to large-scale deltaic lobes that build deltaic plains. Morphodynamic feedbacks among fluid flow, sediment transport, and bed elevation change are ultimately responsible for creating these shapes and patterns, and understanding how this morphodynamic feedback constructs deltaic landscapes will contribute to developing sustainable solutions for threatened deltaic environments. In this review, we explore what morphodynamic modeling approaches are commonly used to understand how deltas grow. We also explore what the community has learned by using these models and highlight key knowledge gaps to inspire new models and new questions about river-dominated deltas