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  1. null (Ed.)
    Co-precipitation of enzymes in metal-organic frameworks is a unique enzyme-immobilization strategy but is challenged by weak acid-base stability. To overcome this drawback, we discovered that Ca2+ can co-precipitate with carboxylate ligands and enzymes under ambient aqueous conditions and form enzyme@metal-organic material composites stable under a wide range of pHs (3.7–9.5). We proved this strategy on four enzymes with varied isoelectric points, molecular weights, and substrate sizes—lysozyme, lipase, glucose oxidase (GOx), and horseradish peroxidase (HRP)—as well as the cluster of HRP and GOx. Interestingly, the catalytic efficiency of the studied enzymes was found to depend on the ligand, probing the origins of which resulted in a correlation among enzyme backbone dynamics, ligand selection, and catalytic efficiency. Our approach resolved the long-lasting stability issue of aqueous-phase co-precipitation and can be generalized to biocatalysis with other enzymes to benefit both research and industry. 
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  2. Abstract We present panchromatic observations and modeling of calcium-strong supernovae (SNe) 2021gno in the star-forming host-galaxy NGC 4165 and 2021inl in the outskirts of elliptical galaxy NGC 4923, both monitored through the Young Supernova Experiment transient survey. The light curves of both, SNe show two peaks, the former peak being derived from shock cooling emission (SCE) and/or shock interaction with circumstellar material (CSM). The primary peak in SN 2021gno is coincident with luminous, rapidly decaying X-ray emission ( L x = 5 × 10 41 erg s −1 ) detected by Swift-XRT at δ t = 1 day after explosion, this observation being the second-ever detection of X-rays from a calcium-strong transient. We interpret the X-ray emission in the context of shock interaction with CSM that extends to r < 3 × 10 14 cm. Based on X-ray modeling, we calculate a CSM mass M CSM = (0.3−1.6) × 10 −3 M ⊙ and density n = (1−4) × 10 10 cm −3 . Radio nondetections indicate a low-density environment at larger radii ( r > 10 16 cm) and mass-loss rate of M ̇ < 10 − 4 M ⊙ yr −1 . SCE modeling of both primary light-curve peaks indicates an extended-progenitor envelope mass M e = 0.02−0.05 M ⊙ and radius R e = 30−230 R ⊙ . The explosion properties suggest progenitor systems containing either a low-mass massive star or a white dwarf (WD), the former being unlikely given the lack of local star formation. Furthermore, the environments of both SNe are consistent with low-mass hybrid He/C/O WD + C/O WD mergers. 
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    We present optical and near-infrared (NIR) observations of the Type Icn supernova (SN Icn) 2022ann, the fifth member of its newly identified class of SNe. Its early optical spectra are dominated by narrow carbon and oxygen P-Cygni features with absorption velocities of ∼800 km s−1; slower than other SNe Icn and indicative of interaction with a dense, H/He-poor circumstellar medium (CSM) that is outflowing slower than typical Wolf–Rayet wind velocities of >1000 km s−1. We identify helium in NIR spectra 2 weeks after maximum and in optical spectra at 3 weeks, demonstrating that the CSM is not fully devoid of helium. Unlike other SNe Icn, the spectra of SN 2022ann never develop broad features from SN ejecta, including in the nebular phase. Compared to other SNe Icn, SN 2022ann has a low luminosity (o-band absolute magnitude of ∼−17.7), and evolves slowly. The bolometric light curve is well-modelled by 4.8 M⊙ of SN ejecta interacting with 1.3 M⊙ of CSM. We place an upper limit of 0.04 M⊙ of 56Ni synthesized in the explosion. The host galaxy is a dwarf galaxy with a stellar mass of 107.34 M⊙ (implied metallicity of log(Z/Z⊙) ≈ 0.10) and integrated star-formation rate of log (SFR) = −2.20 M⊙ yr−1; both lower than 97 per cent of galaxies observed to produce core-collapse supernovae, although consistent with star-forming galaxies on the galaxy Main Sequence. The low CSM velocity, nickel and ejecta masses, and likely low-metallicity environment disfavour a single Wolf–Rayet progenitor star. Instead, a binary companion is likely required to adequately strip the progenitor and produce a low-velocity outflow.

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