Evaluating the Ability of Congenital Upper Extremity Amputees to Control a Multi-Degree of Freedom Myoelectric Prosthesis.

PURPOSE: To determine whether children and adults with unilateral congenital upper limb amputation can control myoelectric prostheses with multiple degrees of freedom (DOF) using pattern recognition (PR) technology. METHODS: Seven participants (age 9-62 years) with unilateral congenital transradial amputation were tested on both their residual and sound side limbs to determine proficiency in controlling a virtual prosthesis using electromyographic signals captured by an array of surface electrodes that were processed using PR technology. Proficiency was measured through a virtual environment game called the target achievement control test, in which the testing protocol asked participants to match increasingly complex prosthesis postures with 1, 2, and 3 DOF. RESULTS: All the participants successfully created a PR calibration at 1, 2, and 3 DOF with their residual limb during testing, and no differences in calibration accuracy were observed when comparing the residual versus sound upper limbs. No differences were noted in the mean completion rate on the target achievement control test between the residual and sound limbs. CONCLUSIONS: Participants with a congenital upper limb amputation achieved PR control calibration of multi-DOF prostheses with proficiency and quality results of PR calibration that were comparable to those of their sound limb. This capability was observed in children as well as in adults. This demonstrates the potential for children and adults with a unilateral congenital transradial amputation to benefit from myoelectric prostheses with PR control. CLINICAL RELEVANCE: The results from this study highlight the potential for patients in this population to benefit from myoelectric prostheses with PR control. Persons with unilateral congenital upper limb amputations can be considered for provision of this technology and enrollment in future research activities.

Vibronic and Coherent Effects on Interfacial Electron Transfer Dynamics.

This Letter examines fundamental issues for electron transfer (ET) dynamics, such as adiabatic versus nonadiabatic effects during interfacial ET, the influence of vibrational degrees of freedom on the electronic dynamics, the occurrence of electronic coherences and the ensuing dephasing effects. The interplay of these mechanisms during the ultrafast ET is discussed. A theoretical method for the quantum dynamics of electrons in flexible molecular systems is used to study such issues on the interfacial ET from the perylene chromophore to the TiO2 semiconductor surface. By analyzing the Fourier transform of the survival probability curves, it is possible to discern the oscillating features that are caused by electronic coherences and vibronic effects. The vibronic degrees of freedom are treated within the atomistic level of description and their effects identified on the charge transfer dynamics. The insights revealed are general and thus can be useful for the analysis of other ET phenomena.

¨Qué‚ significan los grados de libertad? / What do degrees of freedom mean?

Los grados de libertad representan un tema central en la estadística moderna, sin embargo su concepto se explica poco en los libros de texto. A pesar de que Gauss los usó por primera vez al estimar las distancias entre las estrellas, no aparece formalmente hasta los escritos de Gosset (Student) en 1908. El concepto de grados de libertad se puede entender desde un punto de vista geométrico, algebraico e incluso intuitivo. La geometría nos describe a los grados de libertad como espacios e hiperespacios de libertad através de los cuales una medida de resumen puede moverse y tomar diferentes valores. El punto de vista algebraico los describe como el número de ecuaciones que se establecen usando los datos. Ambos puntos de vista est n relacionados y ayudan a comprender con mayor profundidad el concepto de grados de libertad. La aplicaciones de los grados de libertad está n extendidas através de toda la estadstica, el calculo de la desviación estándar y la prueba t de Student son solo algunos ejemplos.

Degrees of freedom is a central topic in modern statistics, however is poor explained in textbooks. Gauss used it for first time in estimates of astronomic distances but it appears formally in Gosset (Student) manuscripts in 1908. Degrees of freedom can be understood from geometric, algebraic or even intuitive point of view. Geometrics shows degrees of freedom as spaces through a summary measure can move freely assuming different values. Algebra describes degrees of freedom as number of unknown variables in respect of number of equations we can establish using data. Both algebraic and geometric points of view are related and help us to understand better the meaning of degrees of freedom. Applications in statistics are widely spread but standard deviation and Student t are just some examples.

Exoesqueletos para potenciar las capacidades humanas y apoyar la rehabilitación: [revisión] / Exoskeletons to enhance human capabilities and support rehabilitation: a state of the art: [review]

El presente artículo presenta una revisión bibliográfica sobre el diseño de exoesqueletos y las diferentes aplicaciones que estos pueden tener en la vida humana. Se exponen diferentes desarrollos, resaltando las partes más importantes de cada uno y prestando especial atención al área de la ingeniería electrónica presente en estas estructuras. Además, se realiza un agrupamiento de los diseños, dependiendo de la zona corporal para la cual se ha construido el exoesqueleto o de la finalidad del estudio realizado. Finalmente, se presentan desarrollos y estudios que buscan utilizar las señales mioeléctricas como parte fundamental del sistema exoesquelético.

This paper presents a literature review about exoskeletons and their applications in human life. Different developments highlighting the most important parts of each of them, and paying particular attention to the area of electronic engineering related to these structures, are shown. Also, a grouping of the different kinds of structures is made depending on the area of the human body to which the exoskeleton was intended to or depending on the purpose of the research. Finally, various studies and developments which use mioelectric signals as a fundamental part of the system are presented.