A science-driven method for determining morphological parameters of prosthetic hands.

The unique morphological bases of human hands, which are distinct from other primates, endow them with excellent grasping and manipulative abilities. However, the lack of understanding of human hand morphology and its parametric features is a major obstacle in the scientific design of prosthetic hands. Existing designs of prosthetic hand morphologies mostly adopt engineering-based methods, which depend on human experience, direct measurements of human hands, or numerical simulation/optimization. This paper explores for the first time a science-driven design method for prosthetic hand morphology, aiming to facilitate the development of prosthetic hands with human-level dexterity. We first use human morphological, movement, and postural data to quantitatively cognize general morphological characteristics of human hands in static, dynamic, functional, and non-functional perspectives. Taking these cognitions as bases, we develop a method able to quickly transfer human morphological parameters to prosthetic hands and endow the prosthetic hands with great grasping/manipulative potential at the same time. We apply this method to the design of an advanced prosthetic hand (called X-hand II) embedded with compact actuating systems. The human-size prosthetic hand can reach wide grasping/manipulative ranges close to those of human hands, replicate various daily grasping types and even execute dexterous in-hand manipulation. This science-driven method may also inspire other artificial limb and bionic robot designs.

Gerstmann-Sträussler-Scheinker: a new phenotype with 'curly' PrP deposits.

Gerstmann-Sträussler-Scheinker (GSS) is a hereditary prion disease typically associated with prion protein (PrP)-containing plaques. The protease-resistant, scrapie PrP (PrPSc) is represented by internal fragments, whereas the C-terminal fragments associated with the other prion diseases are generally underrepresented. Different histopathologic and PrPSc features associated with at least 13 PrP gene (PRNP) mutations have been described in GSS. We report the histopathology and PrP characteristics in a father and son carrying a mutation at PRNP codon 187 that substitutes histidine (H) with arginine (R) and is coupled with valine (V) at position 129 (H187R-129V). The PrP plaques were present in both cases but with different structure and topography and minimal spongiform degeneration. A distinctive, "curly" PrP immunostaining was prominent in one case. The protease-resistant PrPSc differed in amount in the 2 cases, possibly depending on whether plaques or the curly immunostain was present. Two protease-resistant PrP fragments of 14 kDa and 7 kDa with, in at least one case, N-terminus between residues 90-99 and 82-90, respectively, codistributed with the plaques, whereas only very small amounts of the PK-resistant PrP were present in the curly staining regions. PK-resistant PrP recovered from the plaque and curly staining regions appeared to be full length.