Publications

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The highly tunable properties of multi-principal element alloys, commonly known as high-entropy alloys (HEAs), provide a remarkable potential for the development of superior materials for critical structural applications that involve extreme conditions. However, the optimization of the properties of HEAs has been primarily limited to behavior at either low or high temperatures. Here, we report on a non-equiatomic, heterostructured, high-entropy alloy FeNiCoAlTaB which possesses remarkable combinations of mechanical properties across a wide range of temperatures from 77 K to 1073 K. The current metastable alloy presents good ductility and superior engineering tensile strengths of 2.2 GPa, 1.4 GPa, 800 MPa, and 500 MPa at 77 K, 298 K, 873 K, and 1073 K, respectively. This behavior is achieved by a synergic sequence of individual mechanisms that are activated at different temperatures. The alloy even displays pseudoelasticity at 77 K with an applied load up to 2 GPa. This work provides a methodology for tailoring structural heterogeneity and metastability in the design and fabrication of multifunctional HEAs that will outperform known metals and alloys over a wide range of temperatures.

Biological and heterogenous catalysts for electrochemical CO2 reduction often exhibit a high degree of electronic delocalization that serves to minimize overpotential and maximize selectivity over hydrogen evolution. Here, we report a molecular iron(II) complex that achieves a similar feat as a result of strong metal–ligand exchange coupling. This interaction promotes an open-shell singlet electronic structure that drives the electrochemical reduction of CO2 to CO with over 90% selectivity and turnover frequencies of 100,000 s−1 at low overpotentials, with no degradation over 20 hours. The decrease in the thermodynamic barrier engendered by this strong metal–ligand exchange coupling enables homogeneous CO2 reduction catalysis in water without compromising reaction selectivity.

Abstract We present observations of DES16C2nm, the first spectroscopically confirmed hydrogen-free superluminous supernova (SLSN-I) at redshift . DES16C2nm was discovered by the Dark Energy Survey (DES) Supernova Program, with follow-up photometric data from the Hubble Space Telescope , Gemini, and the European Southern Observatory Very Large Telescope supplementing the DES data. Spectroscopic observations confirm DES16C2nm to be at z = 1.998, and spectroscopically similar to Gaia16apd (a SLSN-I at z = 0.102), with a peak absolute magnitude of . The high redshift of DES16C2nm provides a unique opportunity to study the ultraviolet (UV) properties of SLSNe-I. Combining DES16C2nm with 10 similar events from the literature, we show that there exists a homogeneous class of SLSNe-I in the UV ( Å), with peak luminosities in the (rest-frame) U band, and increasing absorption to shorter wavelengths. There is no evidence that the mean photometric and spectroscopic properties of SLSNe-I differ between low ( ) and high redshift ( ), but there is clear evidence of diversity in the spectrum at , possibly caused by the variations in temperature between events. No significant correlations are observed between spectral line velocities and photometric luminosity. Using these data, we estimate that SLSNe-I can be discovered to z = 3.8 by DES. While SLSNe-I are typically identified from their blue observed colors at low redshift ( ), we highlight that at these events appear optically red, peaking in the observer-frame z -band. Such characteristics are critical to identify these objects with future facilities such as the Large Synoptic Survey Telescope, Euclid , and the Wide-field Infrared Survey Telescope , which should detect such SLSNe-I to z = 3.5, 3.7, and 6.6, respectively.

Healthy dentin, the mineralized tissue that makes up the bulk of the tooth, is naturally hydrated in vivo; however, it is known that various chemical reagents, including acetone and ethanol, can induce dehydration and thereby affect its properties. Here, we sought to investigate this in light of the effect of alcohol on the mechanical properties of dentin, specifically by measuring the stiffness, strength, and toughness of dentin in simulated body fluid and Scotch whisky. Results indicated that chemical dehydration induced by the whisky had a significant beneficial effect on the elastic modulus, strength, and fracture toughness of dentin. Although this made teeth more resistant to fracture, the change in properties was fully reversible upon rehydration. This effect is considered to be associated with increased cross-linking of the collagen molecules from intermolecular hydrogen-bonding, where water is replaced with weaker hydrogen-bond-forming solvents such as alcohol.

<i>Streptomyces tsukubaensis</i> NRRL 18488, the primary producer of the immunosuppressant FK506, was analyzed to elucidate regulatory features of secondary metabolism. Completion of its 7.9-Mb linear genome enabled accurate re-annotation of the FK506 biosynthetic gene cluster (BGC). Transcriptome analysis during BGC activation revealed major transcriptional shifts from primary to secondary metabolism, especially in genes involved in FK506 biosynthesis and lysine metabolism. Primary transcriptome mapping identified 1,225 transcription units and uncovered post-transcriptional regulation of allylmalonyl-CoA production, a key FK506 precursor. Ribosome profiling demonstrated that AT-rich codons reduce translational efficiency in <i>S. tsukubaensis</i>, with pronounced ribosome pausing at the TTA codon within the FK506 BGC. Substituting this codon relieved pausing and improved FK506 production. Together, these integrative genomic, transcriptomic, and translatomic analyses highlight how multi-level regulatory mechanisms shape secondary metabolism in <i>Streptomyces</i>. This work offers insights into metabolic control that could inform future efforts in strain improvement for efficient natural products production.