119 research outputs found

    Unprecedented Reactivity And Applications Of 1-Aza-2-Azoniaallene Salts

    Get PDF
    1-Aza-2-azoniaallene salts, derived by oxidation of substituted hydrazones, are highly reactive cationic heteroallenes. These species participate in several mechanistically distinct reactions including: (1) intramolecular [3+2] cycloadditions, (2) polar [4 +2] cycloadditions, (3) stereospecific C-H aminations, (4) electrophilic aromatic substitutions, and (5) chloroamination reactions. We have shown that this versatile reactivity is governed by the length of the tether and nature of the π-system. A novel intramolecular electrophilic aromatic substitution reaction is observed when the tether length separating the 1-aza-2-azoniaallene salt and a pendant aryl ring is three methylene units to generate alkylaryl azo products. Variations in the electronics and sterics of the heteroallenes greatly affects their reactivity. The azo product obtained from 5-phenyl-pentan-2-one undergoes spontaneous photochemical cleavage, exhibiting interesting applications to this class of compounds. Heteroallenes derived from pent-5-ene-2-one scaffolds undergo a concerted polar [4+2] cycloaddition to give a 1,2,3,4-tetrahydrocinnoline product. These products are structural motifs found in biologically and pharmaceutically active compounds. This reaction can give the structurally complex tetracyclic iminium salt from a cyclohexene based heteroallene which serves as good precedence to the key step of our proposed synthesis of a terpene indole alkaloid, (+)-ibophyllidine

    Biaxial Studies of Skin\u27s Mechanical Properties

    Get PDF
    In this research, biaxial tests are performed on 12 pieces of abdomen skin specimen from rats. The results show that skin possesses anisotropy, non-linearity and hysteresis. To explain the stress-strain relationship in terms of the strain-energy function the material constants are determined from the experiments and comparison between the theoretical and experimental result shows a high correlation. These results may provide an insight into better understanding skin’s mechanical propertiesIn this research, biaxial tests are performed on 12 pieces of abdomen skin specimen from rats. The results show that skin possesses anisotropy, non-linearity and hysteresis. To explain the stress-strain relationship in terms of the strain-energy function the material constants are determined from the experiments and comparison between the theoretical and experimental result shows a high correlation. These results may provide an insight into better understanding skin’s mechanical properties

    Building Bridges: Generative Artworks to Explore AI Ethics

    Full text link
    In recent years, there has been an increased emphasis on understanding and mitigating adverse impacts of artificial intelligence (AI) technologies on society. Across academia, industry, and government bodies, a variety of endeavours are being pursued towards enhancing AI ethics. A significant challenge in the design of ethical AI systems is that there are multiple stakeholders in the AI pipeline, each with their own set of constraints and interests. These different perspectives are often not understood, due in part to communication gaps.For example, AI researchers who design and develop AI models are not necessarily aware of the instability induced in consumers' lives by the compounded effects of AI decisions. Educating different stakeholders about their roles and responsibilities in the broader context becomes necessary. In this position paper, we outline some potential ways in which generative artworks can play this role by serving as accessible and powerful educational tools for surfacing different perspectives. We hope to spark interdisciplinary discussions about computational creativity broadly as a tool for enhancing AI ethics

    Broadening AI Ethics Narratives: An Indic Art View

    Full text link
    Incorporating interdisciplinary perspectives is seen as an essential step towards enhancing artificial intelligence (AI) ethics. In this regard, the field of arts is perceived to play a key role in elucidating diverse historical and cultural narratives, serving as a bridge across research communities. Most of the works that examine the interplay between the field of arts and AI ethics concern digital artworks, largely exploring the potential of computational tools in being able to surface biases in AI systems. In this paper, we investigate a complementary direction--that of uncovering the unique socio-cultural perspectives embedded in human-made art, which in turn, can be valuable in expanding the horizon of AI ethics. Through qualitative interviews of sixteen artists, art scholars, and researchers of diverse Indian art forms like music, sculpture, painting, floor drawings, dance, etc., we explore how {\it non-Western} ethical abstractions, methods of learning, and participatory practices observed in Indian arts, one of the most ancient yet perpetual and influential art traditions, can inform the FAccT community. Insights from our study suggest (1) the need for incorporating holistic perspectives (that are informed both by data-driven observations and prior beliefs encapsulating the structural models of the world) in designing ethical AI algorithms, (2) the need for integrating multimodal data formats for design, development, and evaluation of ethical AI systems, (3) the need for viewing AI ethics as a dynamic, cumulative, shared process rather than as a self contained framework to facilitate adaptability without annihilation of values, (4) the need for consistent life-long learning to enhance AI accountability, and (5) the need for identifying ethical commonalities across cultures and infusing the same into AI system design, so as to enhance applicability across geographies

    Synthesis, structure and optical properties of rare-earth benzene carboxylates

    Get PDF
    Two series of rare-earth isophthalates of the general formula, [M2(H2O)] [{C6H4(COO)2}2{C6H4(COOH)(COO)}2]·H2O, M = La (I), Pr (Ia), and Nd (Ib) and [M2(H2O)2][{C6H4(COO)2}3]·H2O, M = Y (II), Gd (IIa), and Dy (IIb) have been prepared by the reaction of the corresponding trivalent lanthanide salts and isophthalic acid under mild hydrothermal conditions. The La (I), Pr (Ia) and Nd (Ib) have MO9 polyhedra connected to the isophthalate anions forming a two-dimensional structure, whereas Y (II), Gd (IIa) and Dy (IIb) have MO7 and MO8 polyhedral units connected to the isophthalate anions forming a different, but related two-dimensional structure. Both the structures are stabilized by hydrogen bonding and π···π/CH···π interactions. Partial substitution of Eu and Tb (2 and 4%) at the La (I) and Y (II) sites give rise to characteristic red/pink or green luminescence, indicating a ligand-sensitized metal-centered emission. The Nd (Ib) compound shows interesting UV and blue emission through an up-conversion process
    • …
    corecore