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This paper delineates the design and realization of a Wheelchair-Mounted Robotic Arm (WMRA), envisioned as an autonomous assistance apparatus for individuals encountering motor difficulties and/or upper limb paralysis. The proposed design solution is based on employing a 3D printing process coupled with optimization design techniques to achieve a cost-oriented and user-friendly solution. The proposed design is based on utilizing commercial Arduino control hardware. The proposed device has been named Pick&Eat. The proposed device embodies reliability, functionality, and cost-effectiveness, and features a modular structure housing a 4-degrees-of-freedom robotic arm with a fixing frame that can be attached to commercial wheelchairs. The arm is integrated with an interchangeable end-effector facilitating the use of various tools such as spoons or forks tailored to different food types. Electrical and sensor components were meticulously designed, incorporating sensors to ensure user safety throughout operations. Smooth and secure operations are achieved through a sequential procedure that is depicted in a specific flowchart. Experimental tests have been carried out to demonstrate the engineering feasibility and effectiveness of the proposed design solution as an innovative assistive solution for individuals grappling with upper limb impairment. Its capacity to aid patients during the eating process holds promise for enhancing their quality of life, particularly among the elderly and those with disabilities. [ABSTRACT FROM AUTHOR]

Atropisomeric, inherently chiral calix(4)arenes are synthesized from syn-proximal and mixed syn-distal calix(4)arenes. The arenes have mixed ligating functionalities at the lower rim. Hydrogen bonding stabilization of the phenolate anion intermediates and the control of conformational outcome of the alkylation process make the synthesis advantageous.

Dynamic NMR techniques and MM2 molecular mechanics calculations are used to investigate the synthesis, X-ray crystal structure and conformational analysis of the complex 5,11,17,23,29, 35-hexa-tert-butyl-37,40-dihydroxy- 38,39,41, 42-tetrakis((2-pyridylmethyl)oxy)calix(6)arene. The complex is prepared from the treatment of p-tert-butylcalix(6)arene with 2-(chloromethyl)pyridine hydrochloride and NaH in N,N-dimethylformamide. The complex is determined to be conformationally flexible in solution.

Nine (2-pyridylmethyl)oxy calix(4)arene conformers may be synthesized by O-alkylation of calix(4)arenes with 2-(chloromethyl)pyridine hydrochloride. Calix(4)arenes are cyclic groups of methylene-linked phenol residues, used as building blocks for lipophilic cation receptors and carriers. The base used in the alkylation determines the conformer type. Sodium hydride produces cones, while potassium or cesium carbonate yields either partial cones or 1,3-alternate conformers. Structures of the cone conformations, based on single-crystal X-ray analysis, are discussed.