119 research outputs found
Unprecedented Reactivity And Applications Of 1-Aza-2-Azoniaallene Salts
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
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
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
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
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
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