Astronomers have found more than a dozen planets transiting stars that are 10-40 million years old, but younger transiting planets have remained elusive. The lack of such discoveries may be because planets have not fully formed at this age or because our view is blocked by the protoplanetary disk. However, we now know that many outer disks are warped or broken; provided the inner disk is depleted, transiting planets may thus be visible.
View Article and Find Full Text PDFHerein, we report an iron-catalyzed transfer hydrogenation of allylic alcohols. The operationally simple protocol employs a well-defined bench stable (cyclopentadienone)iron(0) carbonyl complex as a precatalyst in combination with KCO (4 mol %) and isopropanol as the hydrogen donor. A diverse range of allylic alcohols undergo transfer hydrogenation to form the corresponding alcohols in good yields (33 examples, ≤83% isolated yield).
View Article and Find Full Text PDFFull-spectrum flow cytometry has increased antibody-based multiplexing, yet further increases remain potentially impactful. We recently proposed how fluorescence multiplexing using spectral imaging and combinatorics (MuSIC) could do so using tandem dyes and an oligo-based antibody labeling method. In this work, we found that such labeled antibodies had significantly lower signal intensities than conventionally labeled antibodies in human cell experiments.
View Article and Find Full Text PDFPlanets with radii between that of the Earth and Neptune (hereafter referred to as 'sub-Neptunes') are found in close-in orbits around more than half of all Sun-like stars. However, their composition, formation and evolution remain poorly understood. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment.
View Article and Find Full Text PDFFull-spectrum flow cytometry has increased antibody-based multiplexing, yet further increases remain potentially impactful. We recently proposed how fluorescence Multiplexing using Spectral Imaging and Combinatorics (MuSIC) could do so using tandem dyes and an oligo-based antibody labeling method. In this work, we found that such labeled antibodies had significantly lower signal intensity than conventionally-labeled antibodies in human cell experiments.
View Article and Find Full Text PDFTemperate Earth-sized exoplanets around late-M dwarfs offer a rare opportunity to explore under which conditions planets can develop hospitable climate conditions. The small stellar radius amplifies the atmospheric transit signature, making even compact secondary atmospheres dominated by N or CO amenable to characterization with existing instrumentation. Yet, despite large planet search efforts, detection of low-temperature Earth-sized planets around late-M dwarfs has remained rare and the TRAPPIST-1 system, a resonance chain of rocky planets with seemingly identical compositions, has not yet shown any evidence of volatiles in the system.
View Article and Find Full Text PDFCommunity colleges offer a unique context in higher education and yet specific guidance on implementing the ACRL in community colleges is lacking. Semi-structured interviews with 30 community college librarians who had instruction duties explored the state of the implementation of the in community colleges and the effect of the recent pandemic on information literacy instruction (ILI). The is most lauded for its effect on the design and delivery of instruction, but its components mainly underpin ILI rather than being explicitly taught.
View Article and Find Full Text PDFPurpose: The main objective of this study was to gain insight into school-based speech-language pathologists' (SLPs') perspectives on and experiences with telepractice as a service delivery model at the onset of the COVID-19 global pandemic. A better understanding of the facilitating and challenging factors that belie telepractice-based services will guide the creation of training and resource development to further support remote speech-language services in schools.
Method: Four focus group sessions using a semistructured format were conducted with 22 school-based SLPs from 14 states in the United States.
Ultrashort-period (USP) exoplanets have orbital periods shorter than 1 day. Precise masses and radii of USP exoplanets could provide constraints on their unknown formation and evolution processes. We report the detection and characterization of the USP planet GJ 367b using high-precision photometry and radial velocity observations.
View Article and Find Full Text PDFBorrowing hydrogen is a process that is used to diversify the synthetic utility of commodity alcohols. A catalyst first oxidizes an alcohol by removing hydrogen to form a reactive carbonyl compound. This intermediate can undergo a diverse range of subsequent transformations before the catalyst returns the "borrowed" hydrogen to liberate the product and regenerate the catalyst.
View Article and Find Full Text PDFSpectroscopy of transiting exoplanets can be used to investigate their atmospheric properties and habitability. Combining radial velocity (RV) and transit data provides additional information on exoplanet physical properties. We detect a transiting rocky planet with an orbital period of 1.
View Article and Find Full Text PDFSingle-molecule Förster resonance energy transfer (smFRET) is a powerful technique for investigating the structural dynamics of biological macromolecules. smFRET reveals the conformational landscape and dynamic changes of proteins by building on the static structures found using cryo-electron microscopy, x-ray crystallography, and other methods. Combining smFRET with static structures allows for a direct correlation between dynamic conformation and function.
View Article and Find Full Text PDFAstronomers have discovered thousands of planets outside the Solar System, most of which orbit stars that will eventually evolve into red giants and then into white dwarfs. During the red giant phase, any close-orbiting planets will be engulfed by the star, but more distant planets can survive this phase and remain in orbit around the white dwarf. Some white dwarfs show evidence for rocky material floating in their atmospheres, in warm debris disks or orbiting very closely, which has been interpreted as the debris of rocky planets that were scattered inwards and tidally disrupted.
View Article and Find Full Text PDFAn amendment to this paper has been published and can be accessed via a link at the top of the paper.
View Article and Find Full Text PDFThe clinical translation of Fourier transform infrared (FT-IR) microspectroscopy in pathology will require bringing this technique as close as possible to standard practice in pathology departments. An important step is sample preparation for both FT-IR microspectroscopy and pathology. This should entail minimal disruption of standard clinical practice while achieving good quality FT-IR spectral data.
View Article and Find Full Text PDFThe interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors.
View Article and Find Full Text PDFBlack hole binary systems with companion stars are typically found via their x-ray emission, generated by interaction and accretion. Noninteracting binaries are expected to be plentiful in the Galaxy but must be observed using other methods. We combine radial velocity and photometric variability data to show that the bright, rapidly rotating giant star 2MASS J05215658+4359220 is in a binary system with a massive unseen companion.
View Article and Find Full Text PDFA one-pot iron-catalyzed conversion of allylic alcohols to α-methyl ketones has been developed. This isomerization-methylation strategy utilized a (cyclopentadienone)iron(0) carbonyl complex as precatalyst and methanol as the C1 source. A diverse range of allylic alcohols undergoes isomerization-methylation to form α-methyl ketones in good isolated yields (up to 84% isolated yield).
View Article and Find Full Text PDFMost known terrestrial planets orbit small stars with radii less than 60 per cent of that of the Sun. Theoretical models predict that these planets are more vulnerable to atmospheric loss than their counterparts orbiting Sun-like stars. To determine whether a thick atmosphere has survived on a small planet, one approach is to search for signatures of atmospheric heat redistribution in its thermal phase curve.
View Article and Find Full Text PDFWe present the first good evidence for exocomet transits of a host star in continuum light in data from the mission. The star in question, KIC 3542116, is of spectral type F2V and is quite bright at = 10. The transits have a distinct asymmetric shape with a steeper ingress and slower egress that can be ascribed to objects with a trailing dust tail passing over the stellar disk.
View Article and Find Full Text PDFWe present the Kepler Object of Interest (KOI) catalog of transiting exoplanets based on searching four years of time series photometry (Data Release 25, Q1-Q17). The catalog contains 8054 KOIs of which 4034 are planet candidates with periods between 0.25 and 632 days.
View Article and Find Full Text PDFThe amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300-10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref.
View Article and Find Full Text PDFM dwarf stars, which have masses less than 60 per cent that of the Sun, make up 75 per cent of the population of the stars in the Galaxy. The atmospheres of orbiting Earth-sized planets are observationally accessible via transmission spectroscopy when the planets pass in front of these stars. Statistical results suggest that the nearest transiting Earth-sized planet in the liquid-water, habitable zone of an M dwarf star is probably around 10.
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