Does proprioceptive system stimulation improve sit-to-walk performance in healthy young adults?

[Purpose] Sit-to-walk performance is linked to proper proprioceptive information processing. Therefore, it is believed that an increase of proprioceptive inflow (using muscle vibration) might improve sit-to-walk performance. However, before testing muscle vibration effects on a frail population, assessment of its effects on healthy young people is necessary. Thus, the aim of this study was to investigate the effects of muscle vibration on sit-to-walk performance in healthy young adults. [Subjects and Methods] Fifteen young adults performed the sit-to-walk task under three conditions: without vibration, with vibration applied before movement onset, and with vibration applied during the movement. Vibration was applied bilaterally for 30 s to the tibialis anterior, rectus femoris, and upper trapezius muscles bellies. The vibration parameters were as follows: 120 Hz and 1.2 mm. Kinematics and kinetic data were assessed using a 3D motion capture system and two force plates. The coordinates of reflective markers were used to define the center-of-mass velocities and displacements. In addition, the first step spatiotemporal variables were assessed. [Results] No vibration effect was observed on any dependent variables. [Conclusion] The results show that stimulation of the proprioceptive system with local muscle vibration does not improve sit-towalk performance in healthy young adults.

O papel da propriocepção no desenvolvimento da força muscular e da flexibilidade

Universidade Estadual de Campinas . Faculdade de Educação Física

Confluence : Arts plastiques, élèves à risque et système proprioceptif

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Diferenças sensoriais e motoras entre jovens e idosos: contribuição somatossensorial no controle postural

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Os efeitos da manipulação do sistema proprioceptivo na locomoção de pessoas com doença de Parkinson com e sem congelamento da marcha: desenvolvimento, otimização e aplicabilidade de um sistema de vibração muscular

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Performance statistics of a head-operated force-reflecting rehabilitation robot system

Researchers in the rehabilitation engineering community have been designing and developing a variety of passive/active devices to help persons with limited upper extremity function to perform essential daily manipulations. Devices range from low-end tools such as head/mouth sticks to sophisticated robots using vision and speech input. While almost all of the high-end equipment developed to date relies on visual feedback alone to guide the user providing no tactile or proprioceptive cues, the “low-tech” head/mouth sticks deliver better “feel” because of the inherent force feedback through physical contact with the user's body. However, the disadvantage of a conventional head/mouth stick is that it can only function in a limited workspace and the performance is limited by the user's strength. It therefore seems reasonable to attempt to develop a system that exploits the advantages of the two approaches: the power and flexibility of robotic systems with the sensory feedback of a headstick. The system presented in this paper reflects the design philosophy stated above. This system contains a pair of master-slave robots with the master being operated by the user's head and the slave acting as a telestick. Described in this paper are the design, control strategies, implementation and performance evaluation of the head-controlled force-reflecting telestick system.

A virtual head-stick rehabilitation robot system

For individuals with upper-extremity motor disabilities, the head-stick is a simple and intuitive means of performing manipulations because it provides direct proprioceptive information to the user. Through practice and use of inherent proprioceptive cues, users may become quite adept at using the head-stick for a number of different tasks. The traditional head-stick is limited, however, to the user's achievable range of head motion and force generation, which may be insufficient for many tasks. The authors describe an interface to a robot system which emulates the proprioceptive qualities of a traditional head-stick while also allowing for augmented end-effector ranges of force and motion. The design and implementation of the system in terms of coordinate transforms, bilateral telemanipulator architecture, safety systems, and system identification of the master is described, in addition to preliminary evaluation results.

Proprioceptive neuromuscular facilitation does not increase blood pressure of healthy elderly women

Proprioceptive neuromuscular facilitation (PNF) is an attractive method to increase strength and proprioception of elderly individuals. However, a major clinical concern about the prescription of PNF is the belief that it can cause a cardiovascular overload, because it involves close-to-maximal loads and isometric contractions. Yet the acute effect of a PNF training session on cardiovascular response in elderly individuals is still unknown. Hence, the objective of this study was to evaluate the effect of PNF on diastolic and systolic blood pressure of healthy elderly people. Fifteen older women (mean age 72.40±6.82 years) performed three sets (five repetitions each) of three different PNF techniques (rhythmic initiation, dynamic reversion, and isotonic combination), executing a single movement pattern. Diastolic and systolic blood pressure (DBP and SBP) were evaluated by means of a manual sphygmomanometer immediately before and during the last two repetitions (last set) of each technique. A two-way ANOVA test (time and technique) was performed to investigate the PNF effect on blood pressure. No time (preexercise to postexercise) (p=0.33 for DBP; p=0.06 for SBP) or PNF technique (p=0.75; p=0.81) effect were observed. In conclusion, we can state that the execution of these PNF techniques is safe for the cardiovascular system of healthy elderly women, because no blood pressure increases were found. Copyright © Informa Healthcare USA, Inc.

Proprioceptive force estimation and control for teleoperation in radioactive environments

A medida que se incrementa la energía de los aceleradores de partículas o iones pesados como el CERN o GSI, de los reactores de fusión como JET o ITER, u otros experimentos científicos, se va haciendo cada vez más imprescindible el uso de técnicas de manipulación remota para la interacción con el entorno sujeto a la radiación. Hasta ahora la tasa de dosis radioactiva en el CERN podía tomar valores cercanos a algunos mSv para tiempos de enfriamiento de horas, que permitían la intervención humana para tareas de mantenimiento. Durante los primeros ensayos con plasma en JET, se alcanzaban valores cercanos a los 200 μSv después de un tiempo de enfriamiento de 4 meses y ya se hacía extensivo el uso de técnicas de manipulación remota. Hay una clara tendencia al incremento de los niveles de radioactividad en el futuro en este tipo de instalaciones. Un claro ejemplo es ITER, donde se esperan valores de 450 Sv/h en el centro del toroide a los 11 días de enfriamiento o los nuevos niveles energéticos del CERN que harán necesario una apuesta por niveles de mantenimiento remotos. En estas circunstancias se enmarca esta tesis, que estudia un sistema de control bilateral basado en fuerza-posición, tratando de evitar el uso de sensores de fuerza/par, cuyo contenido electrónico los hace especialmente sensitivos en estos ambientes. El contenido de este trabajo se centra en la teleoperación de robots industriales, que debido a su reconocida solvencia y facilidad para ser adaptados a estos entornos, unido al bajo coste y alta disponibilidad, les convierte en una alternativa interesante para tareas de manipulación remota frente a costosas soluciones a medida. En primer lugar se considera el problema cinemático de teleoperación maestro-esclavo de cinemática disimilar y se desarrolla un método general para la solución del problema en el que se incluye el uso de fuerzas asistivas para guiar al operador. A continuación se explican con detalle los experimentos realizados con un robot ABB y que muestran las dificultades encontradas y recomendaciones para solventarlas. Se concluye el estudio cinemático con un método para el encaje de espacios de trabajo entre maestro y esclavo disimilares. Posteriormente se mira hacia la dinámica, estudiándose el modelado de robots con vistas a obtener un método que permita estimar las fuerzas externas que actúan sobre los mismos. Durante la caracterización del modelo dinámico, se realizan varios ensayos para tratar de encontrar un compromiso entre complejidad de cálculo y error de estimación. También se dan las claves para modelar y caracterizar robots con estructura en forma de paralelogramo y se presenta la arquitectura de control deseada. Una vez obtenido el modelo completo del esclavo, se investigan diferentes alternativas que permitan una estimación de fuerzas externas en tiempo real, minimizando las derivadas de la posición para minimizar el ruido. Se comienza utilizando observadores clásicos del estado para ir evolucionando hasta llegar al desarrollo de un observador de tipo Luenberger-Sliding cuya implementación es relativamente sencilla y sus resultados contundentes. También se analiza el uso del observador propuesto durante un control bilateral simulado en el que se compara la realimentación de fuerzas obtenida con las técnicas clásicas basadas en error de posición frente a un control basado en fuerza-posición donde la fuerza es estimada y no medida. Se comprueba como la solución propuesta da resultados comparables con las arquitecturas clásicas y sin embargo introduce una alternativa para la teleoperación de robots industriales cuya teleoperación en entornos radioactivos sería imposible de otra manera. Finalmente se analizan los problemas derivados de la aplicación práctica de la teleoperación en los escenarios mencionados anteriormente. Debido a las condiciones prohibitivas para todo equipo electrónico, los sistemas de control se deben colocar a gran distancia de los manipuladores, dando lugar a longitudes de cable de centenares de metros. En estas condiciones se crean sobretensiones en controladores basados en PWM que pueden ser destructivas para el sistema formado por control, cableado y actuador, y por tanto, han de ser eliminadas. En este trabajo se propone una solución basada en un filtro LC comercial y se prueba de forma extensiva que su inclusión no produce efectos negativos sobre el control del actuador. ABSTRACT As the energy on the particle accelerators or heavy ion accelerators such as CERN or GSI, fusion reactors such as JET or ITER, or other scientific experiments is increased, it is becoming increasingly necessary to use remote handling techniques to interact with the remote and radioactive environment. So far, the dose rate at CERN could present values near several mSv for cooling times on the range of hours, which allowed human intervention for maintenance tasks. At JET, they measured values close to 200 μSv after a cooling time of 4 months and since then, the remote handling techniques became usual. There is a clear tendency to increase the radiation levels in the future. A clear example is ITER, where values of 450 Sv/h are expected in the centre of the torus after 11 days of cooling. Also, the new energetic levels of CERN are expected to lead to a more advanced remote handling means. In these circumstances this thesis is framed, studying a bilateral control system based on force-position, trying to avoid the use of force/torque sensors, whose electronic content makes them very sensitive in these environments. The contents of this work are focused on teleoperating industrial robots, which due its well-known reliability, easiness to be adapted to these environments, cost-effectiveness and high availability, are considered as an interesting alternative to expensive custom-made solutions for remote handling tasks. Firstly, the kinematic problem of teloperating master and slave with dissimilar kinematics is analysed and a new general approach for solving this issue is presented. The solution includes using assistive forces in order to guide the human operator. Coming up next, I explain with detail the experiments accomplished with an ABB robot that show the difficulties encountered and the proposed solutions. This section is concluded with a method to match the master’s and slave’s workspaces when they present dissimilar kinematics. Later on, the research studies the dynamics, with special focus on robot modelling with the purpose of obtaining a method that allows to estimate external forces acting on them. During the characterisation of the model’s parameters, a set of tests are performed in order to get to a compromise between computational complexity and estimation error. Key points for modelling and characterising robots with a parallelogram structure are also given, and the desired control architecture is presented. Once a complete model of the slave is obtained, different alternatives for external force estimation are review to be able to predict forces in real time, minimizing the position differentiation to minimize the estimation noise. The research starts by implementing classic state observers and then it evolves towards the use of Luenberger- Sliding observers whose implementation is relatively easy and the results are convincing. I also analyse the use of proposed observer during a simulated bilateral control on which the force feedback obtained with the classic techniques based on the position error is compared versus a control architecture based on force-position, where the force is estimated instead of measured. I t is checked how the proposed solution gives results comparable with the classical techniques and however introduces an alternative method for teleoperating industrial robots whose teleoperation in radioactive environments would have been impossible in a different way. Finally, the problems originated by the practical application of teleoperation in the before mentioned scenarios are analysed. Due the prohibitive conditions for every electronic equipment, the control systems should be placed far from the manipulators. This provokes that the power cables that fed the slaves devices can present lengths of hundreds of meters. In these circumstances, overvoltage waves are developed when implementing drives based on PWM technique. The occurrence of overvoltage is very dangerous for the system composed by drive, wiring and actuator, and has to be eliminated. During this work, a solution based on commercial LC filters is proposed and it is extensively proved that its inclusion does not introduce adverse effects into the actuator’s control.

Proprioceptive neuromuscular facilitation stretching - Mechanisms and clinical implications

Proprioceptive neuromuscular facilitation (PNF) stretching techniques are commonly used in the athletic and clinical environments to enhance both active and passive range of motion (ROM) with a view to optimising motor performance and rehabilitation. PNF stretching is positioned in the literature as the most effective stretching technique when the aim is to increase ROM, particularly in respect to short-term changes in ROM. With due consideration of the heterogeneity across the applied PNF stretching research, a summary of the findings suggests that an 'active' PNF stretching technique achieves the greatest gains in ROM, e.g. utilising a shortening contraction of the opposing muscle to place the target muscle on stretch, followed by a static contraction of the target muscle. The inclusion of a shortening contraction of the opposing muscle appears to have the greatest impact on enhancing ROM. When including a static contraction of the target muscle, this needs to be held for approximately 3 seconds at no more than 20% of a maximum voluntary contraction. The greatest changes in ROM generally occur after the first repetition and in order to achieve more lasting changes in ROM, PNF stretching needs to be performed once or twice per week. The superior changes in ROM that PNF stretching often produces compared with other stretching techniques has traditionally been attributed to autogenic and/or reciprocal inhibition, although the literature does not support this hypothesis. Instead, and in the absence of a biomechanical explanation, the contemporary view proposes that PNF stretching influences the point at which stretch is perceived or tolerated. The mechanism(s) underpinning the change in stretch perception or tolerance are not known, although pain modulation has been suggested.

Obesity And Inflammation And The Effect On The Hematopoietic System.

Bone marrow is organized in specialized microenvironments known as 'marrow niches'. These are important for the maintenance of stem cells and their hematopoietic progenitors whose homeostasis also depends on other cell types present in the tissue. Extrinsic factors, such as infection and inflammatory states, may affect this system by causing cytokine dysregulation (imbalance in cytokine production) and changes in cell proliferation and self-renewal rates, and may also induce changes in the metabolism and cell cycle. Known to relate to chronic inflammation, obesity is responsible for systemic changes that are best studied in the cardiovascular system. Little is known regarding the changes in the hematopoietic system induced by the inflammatory state carried by obesity or the cell and molecular mechanisms involved. The understanding of the biological behavior of hematopoietic stem cells under obesity-induced chronic inflammation could help elucidate the pathophysiological mechanisms involved in other inflammatory processes, such as neoplastic diseases and bone marrow failure syndromes.

The Value Of The 2005 International Society Of Urological Pathology (isup) Modified Gleason Grading System As A Predictor Of Biochemical Recurrence After Radical Prostatectomy.

To compare time and risk to biochemical recurrence (BR) after radical prostatectomy of two chronologically different groups of patients using the standard and the modified Gleason system (MGS). Cohort 1 comprised biopsies of 197 patients graded according to the standard Gleason system (SGS) in the period 1997/2004, and cohort 2, 176 biopsies graded according to the modified system in the period 2005/2011. Time to BR was analyzed with the Kaplan-Meier product-limit analysis and prediction of shorter time to recurrence using univariate and multivariate Cox proportional hazards model. Patients in cohort 2 reflected time-related changes: striking increase in clinical stage T1c, systematic use of extended biopsies, and lower percentage of total length of cancer in millimeter in all cores. The MGS used in cohort 2 showed fewer biopsies with Gleason score ≤ 6 and more biopsies of the intermediate Gleason score 7. Time to BR using the Kaplan-Meier curves showed statistical significance using the MGS in cohort 2, but not the SGS in cohort 1. Only the MGS predicted shorter time to BR on univariate analysis and on multivariate analysis was an independent predictor. The results favor that the 2005 International Society of Urological Pathology modified system is a refinement of the Gleason grading and valuable for contemporary clinical practice.

The Applicability Of Ordered Mesoporous Sba-15 And Its Hydrophobic Glutaraldehyde-bridge Derivative To Improve Ibuprofen-loading In Releasing System.

The mesoporous SBA-15 silica with uniform hexagonal pore, narrow pore size distribution and tuneable pore diameter was organofunctionalized with glutaraldehyde-bridged silylating agent. The precursor and its derivative silicas were ibuprofen-loaded for controlled delivery in simulated biological fluids. The synthesized silicas were characterized by elemental analysis, infrared spectroscopy, (13)C and (29)Si solid state NMR spectroscopy, nitrogen adsorption, X-ray diffractometry, thermogravimetry and scanning electron microscopy. Surface functionalization with amine containing bridged hydrophobic structure resulted in significantly decreased surface area from 802.4 to 63.0 m(2) g(-1) and pore diameter 8.0-6.0 nm, which ultimately increased the drug-loading capacity from 18.0% up to 28.3% and a very slow release rate of ibuprofen over the period of 72.5h. The in vitro drug release demonstrated that SBA-15 presented the fastest release from 25% to 27% and SBA-15GA gave near 10% of drug release in all fluids during 72.5 h. The Korsmeyer-Peppas model better fits the release data with the Fickian diffusion mechanism and zero order kinetics for synthesized mesoporous silicas. Both pore sizes and hydrophobicity influenced the rate of the release process, indicating that the chemically modified silica can be suggested to design formulation of slow and constant release over a defined period, to avoid repeated administration.

Electronic And Structural Study Of Pt-modified Au Vicinal Surfaces: A Model System For Pt-au Catalysts.

Two single crystalline surfaces of Au vicinal to the (111) plane were modified with Pt and studied using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) in ultra-high vacuum environment. The vicinal surfaces studied are Au(332) and Au(887) and different Pt coverage (θPt) were deposited on each surface. From STM images we determine that Pt deposits on both surfaces as nanoislands with heights ranging from 1 ML to 3 ML depending on θPt. On both surfaces the early growth of Pt ad-islands occurs at the lower part of the step edge, with Pt ad-atoms being incorporated into the steps in some cases. XPS results indicate that partial alloying of Pt occurs at the interface at room temperature and at all coverage, as suggested by the negative chemical shift of Pt 4f core line, indicating an upward shift of the d-band center of the alloyed Pt. Also, the existence of a segregated Pt phase especially at higher coverage is detected by XPS. Sample annealing indicates that the temperature rise promotes a further incorporation of Pt atoms into the Au substrate as supported by STM and XPS results. Additionally, the catalytic activity of different PtAu systems reported in the literature for some electrochemical reactions is discussed considering our findings.

Inhibitory Effects Of A Cured Antibacterial Bonding System On Viability And Metabolic Activity Of Oral Bacteria.

To evaluate the antimicrobial efficacy of Clearfil SE Protect (CP) and Clearfil SE Bond (CB) after curing and rinsed against five individual oral microorganisms as well as a mixture of bacterial culture prepared from the selected test organisms. Bacterial suspensions were prepared from single species of Streptococcus mutans, Streptococcus sobrinus, Streptococcus gordonii, Actinomyces viscosus and Lactobacillus lactis, as well as mixed bacterial suspensions from these organisms. Dentin bonding system discs (6 mm×2 mm) were prepared, cured, washed and placed on the bacterial suspension of single species or multispecies bacteria for 15, 30 and 60 min. MTT, Live/Dead bacterial viability (antibacterial effect), and XTT (metabolic activity) assays were used to test the two dentin system's antibacterial effect. All assays were done in triplicates and each experiment repeated at least three times. Data were submitted to ANOVA and Scheffe's f-test (5%). Greater than 40% bacteria killing was seen within 15 min, and the killing progressed with increasing time of incubation with CP discs. However, a longer (60 min) period of incubation was required by CP to achieve similar antimicrobial effect against mixed bacterial suspension. CB had no significant effect on the viability or metabolic activity of the test microorganisms when compared to the control bacterial culture. CP was significantly effective in reducing the viability and metabolic activity of the test organisms. The results demonstrated the antimicrobial efficacy of CP both on single and multispecies bacterial culture. CP may be beneficial in reducing bacterial infections in cavity preparations in clinical dentistry.