Homochiral crystallizations of two enantiomeric metal-organic frameworks (MOFs) Ce-MDIP1 and Ce-MDIP2 were achieved by using L- or D-BCIP as chiral inductions, respectively, where the chiralities were characterized by solid state CD spectra. Ce-MDIPs exhibit excellent catalytic activity and high enantioselectivity for the asymmetric cyanosilylation of aromatic aldehydes; the homochiral Cd-TBT MOF having L-PYI as a chiral adduct exhibits stereochemical catalysis toward the Aldol reactions.
Through deposition of APTES-functionalized Al2O3 particles onto a coarse macroporous support, a new strategy to reduce the pore size and simutaneously promote a high density of heterogeneous nucleation sites was developed, and a continuous and thin ZIF-8 membrane exhibiting remarkably high H2 permeance of 5.73 × 10(-5) mol m(-2) s(-1) Pa(-1) and H2/N2 ideal selectivity of 15.4 was achieved.
A multifunctional lanthanide‐organic framework Tb−TCA (H3TCA = tricarboxytriphenylamine) comprising a triphenylamine moiety as an efficient luminescence sensitizer is synthesized by a solvothermal method and structurally characterized. Tb−TCA exhibits lanthanide‐based emission (540 nm) and triphenylamine emission (435 nm) after excitation at 350 nm and works as a luminescent chemosensor towards salicylaldehyde with a sensitivity of 10 ppm under optimized conditions. Tb−TCA features a high concentration of Lewis acid Tb3+ sites and Lewis base triphenylamine sites on its internal surfaces; it thus enables both Knoevenagel and cyanosilylation reactions in a size‐selective fashion. The ratiometric fluorescent response towards aldehydes (I540/I435) demonstrates that the absorption of the porous material is size selective, and the interactions between the aldehyde molecules and the Tb3+ ions play a dominant role in the absorption and activation of the aldehyde substrates. In particular, these studies provide opportunities to directly validate the sorption sites and the catalytic mechanism of the multifunctional Ln metal–organic framework material by luminescence.
A thin tubular CAU-1 membrane of 2-3 μm exhibiting a high CO2 permeance of up to 1.34 × 10(-6) mol m(-2) s(-1) Pa(-1) and a CO2-N2 selectivity of 17.4-22.8 for CO2-N2 mixtures was achieved, demonstrating for the first time that amino-functionalized MOF membranes can provide high CO2-N2 selectivity and possess the potential for CO2 capture from flue gas.
The novel coronavirus, COVID-19, has caused a crisis that affects all segments of the population. As the knowledge and understanding of COVID-19 evolve, an appropriate response plan for this pandemic is considered one of the most effective methods for controlling the spread of the virus. Recent studies indicate that a city Digital Twin (DT) is beneficial for tackling this health crisis, because it can construct a virtual replica to simulate factors, such as climate conditions, response policies, and people's trajectories, to help plan efficient and inclusive decisions.However, a city DTsystem relies on long-term and high-quality data collection to make appropriate decisions, limiting its advantages when facing urgent crises, such as the COVID-19 pandemic. Federated Learning (FL), in which all clients can learn a shared model while retaining all training data locally, emerges as a promising solution for accumulating the insights from multiple data sources efficiently. Furthermore, the enhanced privacy protection settings removing the privacy barriers lie in this collaboration. In this work, we propose a framework that fused city DT with FL to achieve a novel collaborative paradigm that allows multiple city DTs to share the local strategy and status quickly. In particular, an FL central server manages the local updates of multiple collaborators (city DTs), providing a global model that is trained in multiple iterations at different city DT systems until the model gains the correlations between various response plans and infection trends. This approach means a collaborative city DT paradigm fused with FL techniques can obtain knowledge and patterns from multiple DTs and eventually establish a "global view" of city crisis management. Meanwhile, it also helps improve each city's DT by consolidating other DT's data without violating privacy rules. In this paper, we use the COVID-19 pandemic as the use case of the proposed framework. The experimental results on a real dataset with various response plans validate our proposed solution and demonstrate its superior performance.
Cytochrome P450 monooxygenases are versatile heme-thiolate enzymes that catalyze a wide range of reactions. Self-sufficient cytochrome P450 enzymes contain the redox partners in a single polypeptide chain. Here, we present the crystal structure of full-length CYP116B46, a self-sufficient P450. The continuous polypeptide chain comprises three functional domains, which align well with the direction of electrons traveling from FMN to the heme through the [2Fe-2S] cluster. FMN and the [2Fe-2S] cluster are positioned closely, which facilitates efficient electron shuttling. The edge-to-edge straight-line distance between the [2Fe-2S] cluster and heme is approx. 25.3 Å. The role of several residues located between the [2Fe-2S] cluster and heme in the catalytic reaction is probed in mutagenesis experiments. These findings not only provide insights into the intramolecular electron transfer of self-sufficient P450s, but are also of interest for biotechnological applications of self-sufficient P450s.
A visible-light-induced enantioselective aerobic oxidative cross-dehydrogenative coupling between glycine derivatives and simple ketones or aldehydes is achieved.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.