published_or_final_version / Surgery / Master / Master of Surgery

No description available.

published_or_final_version / Physiology / Master / Master of Philosophy

This thesis presents biomimetic control of an anthropomorphic artificial finger actuated by three antagonistic shape memory alloy (SMA) muscle pairs that are each configured in a dual spring-biased configuration. This actuation system forms the basis for biomimetic tendon-driven flexion/extension of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints of the artificial finger, as well as the abduction/adduction of its MCP joint. This work focuses on the design and experimental verification of a new fuzzy pulse-width-modulated proportional-integral-derivative (i.e. fuzzy PWM-PID) controller that is capable of realizing cocontraction of the SMA muscle pairs, as well as online tuning of the PID gains to deal with system nonlinearities and parameter uncertainties. One of the main purposes of this thesis is the proposed biomimetic cocontraction control strategy, which co-activates the antagonistic muscle pairs as a synergistic functional unit. It emulates a similar strategy in neural control, called “common drive,” employed by the central nervous system (CNS). In order to maintain a desired position of a joint, the corresponding agonistic muscle pairs are cocontracted by the CNS and numerical simulations using a dynamic model of the system. The performance advantage of the cocontracting fuzzy PWM-PID controller over the original PWM-PID controller is shown by experimental results. A successful application of the new controller to fingertip trajectory tracking tasks using the MCP joint’s flexion/extension and abduction/adduction is also described. Since commercially available SMA actuators used for artificial muscle pairs have limited stroke, a new compact design was considered to increase the stroke of SMA actuators with similar power capacity. The design and fabrication process of the new SMA actuators are described followed by preliminary testing of the actuators’ performance as artificial muscle pairs with the designed fuzzy PWM-PID control algorithm. / Graduate

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 220-230). Also available via the Internet

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--Slippery Rock University, 2002. / Includes bibliographical references (leaves 39-41).

Thesis (M. Med. Sc.)--University of Hong Kong, 2005.

Resumo: YacG é uma pequena proteína (65 resíduos de aminoácidos) ligada ao zinco codificada pelo gene yacG de Escherichia coli. Seu papel fisiológico não está bem caracterizado, porém acredita-se que ela exerça ação inibitória sobre a atividade catalítica da DNA girase, enzima responsável por alterações no estado topológico do DNA bacteriano. Com base nas informações da estrutura primária desta proteína, uma série constituída de oito seqüências peptídicas foram projetadas e sintetizadas pela metodologia da fase sólida, objetivando-se avaliar e melhor entender o efeito da coordenação do íon zinco no seu mecanismo de ação. As sequências foram projetadas de maneira a resultar em uma substituição parcial ou integral dos resíduos de cisteína da sequência nativa da YacG, por resíduos de serina, além da variação da carga efetiva da molécula, por amidação ou acetilação das extremidades C e N terminais, respectivamente. Os peptídeos obtidos e purificados foram ensaiados quanto à estequiometria de coordenação empregando titulação com íon cobalto, bem como na capacidade inibitória frente à DNA girase, empregando eletroforese em gel de agarose. YacGAG4, inibiu a atividade de superenovelamento do DNA, catalisada pela girase, somente na ausência de íons zinco em concentrações inferiores a 120 μmol.L-1. Os demais peptídeos não apresentaram capacidade inibitória, tanto na presença quanto na ausência de zinco. Ensaios de susceptibilidade bacteriana, empregando algumas espécies de bactérias da família Enterobacteriaceae, confirmaram os resultados in vitro,com exceção das sequências YacGAG1-AC e YacGAG2-AC que mostraram inibição no crescimento bacteriano, sem porém resultarem em atividade in vitro. Com base nos resultados obtidos, é possível concluir que o domínio estrutural relacionado à coordenação do zinco, bem como a presença... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: YacG is a small protein (65 amino acid residues) bounded to zinc and encoded by the Escherichia coli yacG gene. Its physiological role is not well characterized, but it is believed that YacG is an inhibitor of the catalytic activity of DNA gyrase, an enzyme responsible for changes in the topological state of bacterial DNA. Based on information from the primary structure of this protein, a series of eight peptide sequences were designed and synthesized by solid phase methodology, aiming to evaluate and better understand the effect of zinc coordination of in their mechanism of action. The sequences were designed so as to result in a partial or full replacement of the cysteine residues of the native YacG sequence by serine residues and to change the effective charge of the molecule by amidation or acetylation of C and N terminal ends, respectively. The obtained peptides were purified and tested by titration with cobalt ion (coordination stoichiometry), as well as by inhibitory effect against the DNA gyrase, using agarose gel electrophoresis. YacGAG4 inhibited DNA supercoiling activity catalyzed by gyrase only in the zinc ions absence at concentrations below of 120 μmol.L-1. The other peptides showed no inhibitory effect in both the presence and absence of zinc. Bacterial susceptibility tests, using some species of bacteria of the Enterobacteriaceae, confirmed in vitro results, with the exception of the sequences YacGAG1-AC and YacGAG2-AC that showed inhibition of bacterial growth, but no in vitro activity. Based on these results, we conclude that the structural matters related to the coordination of zinc as well as the presence of this ion, showed no significant importance in the activity of DNA gyrase inhibition. In this case, the inhibition of activity recently proposed, should be linked to any other region of the protein molecule, structurally organized when the zinc ion is bound... (Complete abstract click electronic access below) / Orientador: Reinaldo Marchetto / Coorientador: Saulo Santesso Garrido / Banca: Clarice Queico Fujimura Leite / Banca: Vani Xavier de Oliveira Junior / Mestre