/library/oar/handle/123456789/907 2025-11-05T10:08:52Z /library/oar/handle/123456789/140715 Title: N-unsubstituted dihydropyridines and pyridones via multicomponent synthesis under a bio-derived heterogeneous catalyst Authors: Bosica, Giovanna; Abdilla, Roderick Abstract: In our exploration of metal-free and cost-effective heterogeneous catalysts for MCRs, we identified a novel system: piperazine immobilized within an agar matrix, functioning as a recyclable and reusable catalyst. This system efficiently facilitates the synthesis of dihydropyridines (DHPs) via one-pot condensation of dimedone, aldehydes, ammonium acetate, and various active methylene compounds—specifically malononitrile, acetophenone, or Meldrum's acid. A broad range of products was obtained, underscoring the versatility of the methodology. Notably, our prior investigations demonstrated this catalyst's efficacy in synthesizing N-aryl-substituted DHPs, affirming its general applicability. Additionally, fluorescence and UV absorption studies, along with in-depth characterization using 2D NMR spectroscopy, were conducted to confirm the structure and peak assignments of the synthesized products. 2025-01-01T00:00:00Z /library/oar/handle/123456789/140251 Title: Naphthalimide–organometallic hybrids as multi-targeted anticancer and luminescent cellular imaging agents Authors: Magri, David C.; Johnson, Alex D. Abstract: 1,8-Naphthalimides with an organometallic moiety with anticancer and luminescence or photoactive properties are reviewed. Primarily highlighted are 1,8-naphthalimide complexes with iron, platinum, and ruthenium, while honourable mentions are given to iridium, rhenium and rhodium complexes. The cytotoxicity, mechanism of action and cell selectivity of the compounds are discussed alongside their photophysical properties for monitoring interactions with biomolecules, most notably DNA, by absorption, fluorescence and dichroism spectroscopy. The luminescence properties provide additional insight regarding the cellular uptake and location of the intelligent agents within both cancer and healthy cells. The versatility of this emerging hybrid class of molecules earmarks them as multi-functional therapeutic and cellular imaging agents. The review concludes with suggestions for designing more effective multi-targeting cytotoxic agents with improved biocompatibility and imaging in hopes of enhancing their clinical potential. 2025-01-01T00:00:00Z /library/oar/handle/123456789/138311 Title: On the behavior of auxetic inserts : a numerical analysis to derive design guidelines Authors: Di Brizzi, Diego; Graziosi, Serena; Bondin, William; Grima, Joseph N.; Airoldi, Alessandro Abstract: Auxetics are a class of materials and metamaterials with a negative Poisson’s ratio (ν) and have gained tremendous popularity over the last three decades. Many studies have focused on characterizing designs that allow obtaining a negative ν. However, some open issues remain concerning understanding the auxetic behavior in operational conditions. Studies have been centered on analyzing the response of specific auxetic topologies instead of treating auxeticity as a property to be analyzed in a well-defined structural context. This study aims to contribute to the investigation of auxetic materials with a structural application, focusing on maximizing performance. The field of application of auxetics for designing inserts was selected and a model of a nail-cavity system was created to determine the effects of different design choices on the system behavior by exploring relationships between selected parameters and the auxetic insert behavior. The exploration combines finite element modeling analyses with their surrogate models generated by supervised learning algorithms. This approach allows for exploring the system’s behavior in detail, thus demonstrating the potential effectiveness of auxetics when used for such applications. A list of design guidelines is elaborated to support the exploitation of auxetics in nail-cavity systems. 2024-01-01T00:00:00Z /library/oar/handle/123456789/138183 Title: Reinforcement of graphene nanoplatelets on water uptake and thermomechanical behaviour of epoxy adhesive subjected to water ageing conditions Authors: Jia, Zhemin; Ye, Haoyan; Liu, Qian; Zhang, Zhicheng; Grima, Joseph N. Abstract: Adhesive joints are frequently utilized due to their lightweight nature and minimal damage to the substrates. However, their application is constrained by a lack of reliable performance under moist conditions. This study assesses the impact of incorporating varying concentrations (0.25–0.75 wt%) of graphene nanoplatelets (GNPs) on moisture uptake, dynamic thermal properties, and tensile behaviour of engineered epoxy adhesives when subjected to water for periods of up to 8 weeks. The objective of this study is to ascertain the optimal concentration from the standpoint of degradation in the thermomechanical performance of the epoxy resulting from water ageing. The addition of GNP results in a 45% reduction in the diffusion coefficient of the 0.25 wt% GNP-modified epoxy relative to the unmodified epoxy. The reduced absorption of water by the GNP-reinforced adhesive results in diminished thermomechanical degradation, particularly during the initial immersion period (less than 14 days). The loss modulus exhibits an increase of up to 21% in comparison with the unmodified epoxy. The reduction in tensile strength of the modified epoxy is 53% less than that of the unmodified epoxy following 14 days of water ageing. Under the same water ageing conditions for 14 days, the epoxy modified with 0.25 wt% GNP exhibited a 75% increase in tensile strength compared to the unmodified epoxy. This work may facilitate the GNP application in epoxy adhesive joints, thereby enhancing their durability under high humidity conditions. 2024-01-01T00:00:00Z