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The study of t-designs with certain highly symmetric properties and the classification of their automorphism groups is one of the important topics of algebraic combinatorics. Hitherto the classification of flag-transitive Steiner t-designs has been completely settled by Huber. Nevertheless, it is interesting that the results of t-designs will get richer when G-flag-transitivity are weakened to G-block-transitivity and the research work becomes more challenging as well. Depending on the classification of finite simple groups and 2-transitive permutation groups, we show the classification of block-transitive Steiner t-designs admitting a block-transitive automorphism group with sporadic socle, and draw a conclusion as follows: Let D=(P,E) be a non-trivial Steiner t-design and G≤Aut(D) be point-primitive. If the socle of G is a sporadic simple group, then G acts block-transitively on D if and only if G acts flag-transitively on D, and D is one of the five known flag-transitive Steiner t-designs.(研究具有某种高度对称性的t-设计及其自同构群的分类问题是代数组合学的重要课题之一。目前关于旗传递Steiner t-设计的分类问题已被Huber解决。然而当设计的自同构群的旗传递性减弱为区传递时，研究结果更加丰富，工作也更加困难。利用有限单群分类定理及2-传递置换群的分类结果，解决了自同构群为散在单群的区传递Steiner t-设计的分类问题，并证明了：设D=(P,E)为非平凡Steiner t-设计且G≤Aut(D)为点本原群，若G的基柱Soc(G)为散在单群，则G区传递作用在D上当且仅当G旗传递作用在D上，且D为已知的5种旗传递Steiner t-设计之一。)

The fundamental mission of the library is to provide users with unrestricted access to library resources anytime, anywhere regardless of their physical location, disability, or other circumstances. Library Access Service departments across the nation have been an innovation engine of creativity and opportunity for many decades. The global epidemiology outbreak experience illuminates areas for potential reforming beyond traditional library services. Controlled Digital Lending (CDL) is one of the emerging modern technologies libraries have used to deliver information digitally in support of online learning and teaching, to make educational materials more affordable and more accessible during the global health crisis. CDL opens a new frontier of library services, as a mechanism for the library practice to enhance user's experience of using libraries' services. By exploring this tool, libraries can distribute resources in an effective and equitable way. This paper shares the journey of piloting a CDL program at a large R1 institution to ensure students have reliable, affordable access to course materials they need during the pandemic. The paper demonstrates the development of the CDL platforms, policies, and implementation plans and further discusses challenges and lessons learned and how the library community plans to sustain the program into future library services.

Recycling waste polymeric materials is essential for environmental protection and achieving carbon neutrality. This study demonstrates the efficacy of CO2 as a metal-free catalyst for the chemical recycling of common waste polyester and polycarbonate plastics via alcoholysis to yield valuable organic chemicals. CO2 was proposed to act as a Lewis acid–base pair, activating both alcohol and ester (carbonate) functional groups during the catalytic process. The depolymerization mechanism was thoroughly investigated by monitoring conversion rates and changes in Mn values. Pre-treatment of the polymer materials in THF was found to accelerate the depolymerization rate. End-of-life waste materials were completely degraded into valuable organic molecules, irrespective of their physical and chemical properties. Unlike conventional solid and liquid catalysts, CO2 leaves no residue in the final products. Moreover, this work unveils the catalytic role for CO2, expanding its traditional function as a C1 building block in synthetic chemistry. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Converting CO2 into valuable chemicals is an effective means to alleviate environmental pressure and the depletion of oil resources. Among them, polymers derived from the copolymerization of PO and CO2 have been widely studied because of their excellent properties. To meet the expansion of the application range of CO2‐based polymers, regulation of the CU in the polymer is imperative. Based on the understanding of the relationship between catalyst synergy and structure, we designed a new generation of polyester‐based polymeric catalysts APEPC‐R and RPEPC‐N with discretely distributed active centers to achieve the synthesis of CO2‐based polymers with regulated CU (from 50% to 90%). The discrete arrangement of catalyst active centers was demonstrated by 1H NMR and UV‐vis characterization. Benefiting from multi‐site synergy, high molecular weight (Mn > 100 kg/mol) CO2‐based copolymers with CU among 50%—90% were successfully synthesized and their properties were firstly investigated. This work not only contributes to enriching the scope of the application of CO2‐based copolymers but also provides a new platform for the development of a new generation of catalysts. [ABSTRACT FROM AUTHOR]

Light‐assisted 3D printing technology, which uses a light source to solidify a photopolymerizable prepolymer solution, has shown great potential in the development of antibacterial hydrogels with high‐resolution, specific features and functionalities. 3D‐printed hydrogels with customized structures and antibacterial functions are widely used in tissue engineering, regenerative medicine, wound healing, and implants to advance the modeling and treatment of diseases. In the current review, an overview of light‐assisted 3D printing technologies is first provided for the development of antibacterial hydrogels. Novel strategies involving the integration of inorganic nanomaterials, antibiotics, and functional polymers into 3D‐printed hydrogels for the enhancement of antibacterial effects are then discussed. Finally, the perspective of advanced design using artificial intelligence and machine learning is proposed, providing a comprehensive yet succinct examination of 3D‐printed hydrogels for antibacterial purposes. [ABSTRACT FROM AUTHOR]