Compared with conventional, solution-phase approaches, solid-state reaction methods can provide unique access to novel synthetic targets. Nanothreads-one-dimensional diamondoid polymers formed through the compression of small molecules-represent a new class of materials produced via solid-state reactions, however, the formation of chemically homogeneous products with targeted functionalization represents a persistent challenge. Through careful consideration of molecular precursor stacking geometry and functionalization, we report here the scalable synthesis of chemically homogeneous, functionalized nanothreads through the solid-state polymerization of 2,5-furandicarboxylic acid. The resulting product possesses high-density, pendant carboxyl functionalization along both sides of the backbone, enabling new opportunities for the post-synthetic processing and chemical modification of nanothread materials applicable to a broad range of potential applications.

The 2021 La Palma eruption provided an unpreceded opportunity to test the relationship between earthquake hypocenters and the location of magma reservoirs. We performed density measurements on CO2-rich fluid inclusions (FIs) hosted in olivine crystals that are highly sensitive to pressure via calibrated Raman spectroscopy. This technique can revolutionize our knowledge of magma storage and transport during an ongoing eruption, given that it can produce precise magma storage depth constraints in near real time with minimal sample preparation. Our FIs have CO2 recorded densities from 0.73 to 0.98g/cm3, translating into depths of 15 to 27km, which falls within the reported deep seismic zone recording the main melt storage reservoir.

Populating the exoplanet mass-radius diagram in order to identify the underlying relationship that governs planet composition is driving an interdisciplinary effort within the exoplanet community. The discovery of hot super-Earths & mdash;a high-temperature, short-period subset of the super-Earth planet population & mdash;has presented many unresolved questions concerning the formation, evolution, and composition of rocky planets. We report the discovery of a transiting, ultra-short-period hot super-Earth orbiting TOI-1075 (TIC 351601843), a nearby (d = 61.4 pc) late-K/early-M-dwarf star, using data from the Transiting Exoplanet Survey Satellite. The newly discovered planet has a radius of 1.791(-0.081)(+0.116) R-circle plus and an orbital period of 0.605 day (14.5 hr). We precisely measure the planet mass to be 9.95(-1.30) (+1.36) M-circle plus using radial velocity measurements obtained with the Planet Finder Spectrograph mounted on the Magellan II telescope. Our radial velocity data also show a long-term trend, suggesting an additional planet in the system. While TOI-1075 b is expected to have a substantial H/He atmosphere given its size relative to the radius gap, its high density ( 9.32(-1.85)(+2.05) g cm(-3)) is likely inconsistent with this possibility. We explore TOI-1075 b's location relative to the M-dwarf radius valley, evaluate the planet's prospects for atmospheric characterization, and discuss potential planet formation mechanisms. Studying the TOI -1075 system in the broader context of ultra-short-period planetary systems is necessary for testing planet formation and evolution theories and density-enhancing mechanisms and for future atmospheric and surface characterization studies via emission spectroscopy with the JWST.

C. reinhardtii has two putative SEC23 genes, CrSEC23A and CrSEC23B. The encoded polypeptides are only similar to 18.9% identical, suggesting that they might have different functions. It is not clear whether SEC23 paralogs have same or different functions in diverse organisms. Interestingly, our alignment and homology modeling showed that CrSEC23B does not have the conserved SEC24 binding motif (VFR), but instead appears to have an LPA motif in the same position. While LPA might be part of a novel SEC24 binding motif, CrSEC23B might have an alternate function that is either associated with or independent of COPII. Our results also show SEC23 orthologs in various organisms have variations in the putative SEC24 binding motif. Phylogenetic analyses place the SEC23 orthologs into two clusters that we designated group A (conventional; CrSEC23A-like orthologs) and group B (unconventional; CrSEC23B-like orthologs). Our results suggest that many photosynthetic organisms have a divergent SEC23 paralog. This divergence is not seen in animals. We hypothesize that divergent (unconventional) SEC23 paralogs might be the result of gene duplication and divergence that may facilitate specific aspects of trafficking. Since we only identified the B-like proteins in photosynthetic lineages, we hypothesize that B-like proteins may not have been present in the common ancestor involved in the primary endosymbiotic event.

Populating the exoplanet mass-radius diagram in order to identify the underlying relationship that governs planet composition is driving an interdisciplinary effort within the exoplanet community. The discovery of hot super-Earths & mdash;a high-temperature, short-period subset of the super-Earth planet population & mdash;has presented many unresolved questions concerning the formation, evolution, and composition of rocky planets. We report the discovery of a transiting, ultra-short-period hot super-Earth orbiting TOI-1075 (TIC 351601843), a nearby (d = 61.4 pc) late-K/early-M-dwarf star, using data from the Transiting Exoplanet Survey Satellite. The newly discovered planet has a radius of 1.791(-0.081)(+0.116) R-circle plus and an orbital period of 0.605 day (14.5 hr). We precisely measure the planet mass to be 9.95(-1.30) (+1.36) M-circle plus using radial velocity measurements obtained with the Planet Finder Spectrograph mounted on the Magellan II telescope. Our radial velocity data also show a long-term trend, suggesting an additional planet in the system. While TOI-1075 b is expected to have a substantial H/He atmosphere given its size relative to the radius gap, its high density ( 9.32(-1.85)(+2.05) g cm(-3)) is likely inconsistent with this possibility. We explore TOI-1075 b's location relative to the M-dwarf radius valley, evaluate the planet's prospects for atmospheric characterization, and discuss potential planet formation mechanisms. Studying the TOI -1075 system in the broader context of ultra-short-period planetary systems is necessary for testing planet formation and evolution theories and density-enhancing mechanisms and for future atmospheric and surface characterization studies via emission spectroscopy with the JWST.

We report the discovery of Pegasus IV, an ultra-faint dwarf galaxy found in archival data from the Dark Energy Camera processed by the DECam Local Volume Exploration Survey. Pegasus IV is a compact, ultra-faint stellar system ( = -r(1/2) 41(-6)(+8) pc; M-V = -4.25 +/- 0.2 mag) located at a heliocentric distance of 90(-6)(+4) kpc. Based on spectra of seven nonvariable member stars observed with Magellan/IMACS, we confidently resolve Pegasus IV's velocity dispersion, measuring s = sigma(v) 3.3(-1.1)(+1.7) km s(-1) (after excluding three velocity outliers); this implies a mass-to-light ratio of M1/2LV ,(1/2)=167(-99)(+224) M-?/L-? for the system. From the five stars with the highest signal-to-noise spectra, we also measure a systemic metallicity of [Fe/H] = -2.63(-0.30)(+0.26) dex, making Pegasus IV one of the most metal-poor ultra-faint dwarfs. We tentatively resolve a nonzero metallicity dispersion for the system. These measurements provide strong evidence that Pegasus IV is a dark-matter-dominated dwarf galaxy, rather than a star cluster. We measure Pegasus IV's proper motion using data from Gaia Early Data Release 3, finding (mu(alpha*, mu delta)) = (0.33 +/- 0.07, -0.21 +/- 0.08) mas yr(-1). When combined with our measured systemic velocity, this proper motion suggests that Pegasus IV is on an elliptical, retrograde orbit, and is currently near its orbital apocenter. Lastly, we identify three potential RR Lyrae variable stars within Pegasus IV, including one candidate member located more than 10 half-light radii away from the system's centroid. The discovery of yet another ultra-faint dwarf galaxy strongly suggests that the census of Milky Way satellites is still incomplete, even within 100 kpc.

Fe2P-type dioxides are significant both for geoscience and condensed-matter physics. For example, Fe2P-type SiO2 has been proposed to be one of the dominant components in the mantles of super-Earths and Fe2P-type TiO2 has been shown to have a large visible absorbance. Here we report the discovery of an Fe2P-type phase in a typical transition-metal dichalcogenide (TMD), TiTe2, using crystal structure prediction and first-principles calculations. Ambient layered TiTe2 will first transform to a monoclinic C2/m phase and then finally to the hexagonal Fe2P-type phase above 33 GPa. Fe2P-type TiTe2 is predicted to be metallic, contrasting with the semiconductivity of Fe2P-type TiO2. The same high-pressure phase (Fe2P type) appears both in transition-metal dioxides and TMDs, indicating that the stacking patterns of anions and cations play an increasingly important role in determining the high-pressure phase.