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Sample records for neuromuscular control mechanisms

  1. Muscle mechanics and neuromuscular control

    NARCIS (Netherlands)

    Hof, AL

    2003-01-01

    The purpose of this paper is to demonstrate that the properties of the mechanical system, especially muscle elasticity and limb mass, to a large degree determine force output and movement. This makes the control demands of the central nervous system simpler and more robust. In human triceps surae, a

  2. Altered neuromuscular control mechanisms of the trapezius muscle in fibromyalgia

    Directory of Open Access Journals (Sweden)

    Karlsson Stefan J

    2010-03-01

    Full Text Available Abstract Background fibromyalgia is a relatively common condition with widespread pain and pressure allodynia, but unknown aetiology. For decades, the association between motor control strategies and chronic pain has been a topic for debate. One long held functional neuromuscular control mechanism is differential activation between regions within a single muscle. The aim of this study was to investigate differences in neuromuscular control, i.e. differential activation, between myalgic trapezius in fibromyalgia patients and healthy controls. Methods 27 fibromyalgia patients and 30 healthy controls performed 3 minutes bilateral shoulder elevations with different loads (0-4 Kg with a high-density surface electromyographical (EMG grid placed above the upper trapezius. Differential activation was quantified by the power spectral median frequency of the difference in EMG amplitude between the cranial and caudal parts of the upper trapezius. The average duration of the differential activation was described by the inverse of the median frequency of the differential activations. Results the median frequency of the differential activations was significantly lower, and the average duration of the differential activations significantly longer in fibromyalgia compared with controls at the two lowest load levels (0-1 Kg (p Conclusion these findings illustrate a different neuromuscular control between fibromyalgia patients and healthy controls during a low load functional task, either sustaining or resulting from the chronic painful condition. The findings may have clinical relevance for rehabilitation strategies for fibromyalgia.

  3. Neuromuscular Control and Coordination during Cycling

    Science.gov (United States)

    Li, Li

    2004-01-01

    The neuromuscular control aspect of cycling has been investigated through the effects of modifying posture and cadence. These studies show that changing posture has a more profound influence on neuromuscular coordination than does changing slope. Most of the changes with standing posture occur late in the downstroke: increased ankle and knee joint…

  4. NEUROMUSCULAR CONTROL IN LUMBAR DISORDERS

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    Ville Leinonen

    2004-03-01

    Full Text Available Impaired motor and sensory functions have been associated with low back pain (LBP. This includes disturbances in a wide range of sensorimotor control e.g. sensory dysfunctions, impaired postural responses and psychomotor control. However, the physiological mechanisms, clinical relevance and characteristics of these findings in different spinal pathologies require further clarification. The purposes of this study were to investigate postural control, lumbar muscle function, movement perception and associations between these findings in healthy volunteers (n=35, patients with lumbar disc herniation (n=20 and lumbar spinal stenosis (LSS, n=26. Paraspinal muscle responses for sudden upper limb loading and muscle activation during flexion-extension movement and the lumbar endurance test were measured by surface electromyography (EMG. Postural stability was measured on a force platform during two- and one-footed standing. Lumbar movement perception was assessed in a motorised trunk rotation unit in the seated position. In addition, measurements of motor-(MEP and somatosensory evoked potentials (SEP and needle EMG examination of lumbar multifidus muscles were performed in the LSS patients. Clinical and questionnaire data were also recorded. A short latency paraspinal muscle response (~50 ms for sudden upper limb loading was observed. The latency of the response was shortened by expectation (p=0.017. The response latency for unexpected loading was similar in healthy persons and disc herniation patients but the latency was not shortened by expectation in the patients (p = 0.014. Also impaired postural control (p < 0.05 and lumbar movement perception (p = 0.012 were observed in disc herniation patients. The impaired lumbar movement perception (p=0.054 and anticipatory muscle activation (p = 0.043 tended to be restored after successful surgery but postural control had still not recovered after 3 months of follow-up. The majority of LSS patients were unable

  5. Assessing neuromuscular mechanisms in human-exoskeleton interaction.

    Science.gov (United States)

    Sylla, N; Bonnet, V; Venture, G; Armande, N; Fraisse, P

    2014-01-01

    In this study, we propose to evaluate a 7 DOF exoskeleton in terms of motion control. Using criteria from the human motor control literature, inverse optimization was performed to assess an industrial screwing movement. The results of our study show that the hybrid composition of the free arm movement was accurately determined. At contrary, when wearing the exoskeleton, which produces an arbitrary determined torque compensation, the motion is different from the naturally adopted one. This study is part of the evaluation and comprehension of the complex neuromuscular mechanism resulting in wearing an exoskeleton several hours per day for industrial tasks assistance.

  6. Proprioceptive Neuromuscular Facilitation (PNF): Its Mechanisms and Effects on Range of Motion and Muscular Function

    OpenAIRE

    Hindle, Kayla B.; Whitcomb, Tyler J.; Briggs, Wyatt O.; Hong, Junggi

    2012-01-01

    Proprioceptive neuromuscular facilitation (PNF) is common practice for increasing range of motion, though little research has been done to evaluate theories behind it. The purpose of this study was to review possible mechanisms, proposed theories, and physiological changes that occur due to proprioceptive neuromuscular facilitation techniques. Four theoretical mechanisms were identified: autogenic inhibition, reciprocal inhibition, stress relaxation, and the gate control theory. The studies s...

  7. The use of "stabilization exercises" to affect neuromuscular control in the lumbopelvic region: a narrative review.

    Science.gov (United States)

    Bruno, Paul

    2014-06-01

    It is well-established that the coordination of muscular activity in the lumbopelvic region is vital to the generation of mechanical spinal stability. Several models illustrating mechanisms by which dysfunctional neuromuscular control strategies may serve as a cause and/or effect of low back pain have been described in the literature. The term "core stability" is variously used by clinicians and researchers, and this variety has led to several rehabilitative approaches suggested to affect the neuromuscular control strategies of the lumbopelvic region (e.g. "stabilization exercise", "motor control exercise"). This narrative review will highlight: 1) the ongoing debate in the clinical and research communities regarding the terms "core stability" and "stabilization exercise", 2) the importance of sub-grouping in identifying those patients most likely to benefit from such therapeutic interventions, and 3) two protocols that can assist clinicians in this process.

  8. Fuzzy Control Method with Application for Functional Neuromuscular Stimulation System

    Institute of Scientific and Technical Information of China (English)

    吴怀宇; 周兆英; 熊沈蜀

    2001-01-01

    A fuzzy control technique is applied to a functional neuromuscular stimulation (FNS) physicalmultiarticular muscle control system. The FNS multiarticular muscle control system based on the fuzzy controllerwas developed with the fuzzy control rule base. Simulation experiments were then conducted for the joint angletrajectories of both the elbow flexion and the wrist flexion using the proposed fuzzy control algorithm and aconventional PID control algorithm with the FNS physical multiarticular muscle control system. The simulationresults demonstrated that the proposed fuzzy control method is more suitable for the physiologicalcharacteristics than conventional PID control. In particular, both the trajectory-following and the stability of theFNS multiarticular muscle control system were greatly improved. Furthermore, the stimulating pulse trainsgenerated by the fuzzy controller were stable and smooth.``

  9. Invasive home mechanical ventilation, mainly focused on neuromuscular disorders

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    Börger, Sandra

    2010-01-01

    Full Text Available Introduction and background: Invasive home mechanical ventilation is used for patients with chronic respiratory insufficiency. This elaborate and technology-dependent ventilation is carried out via an artificial airway (tracheal cannula to the trachea. Exact numbers about the incidence of home mechanical ventilation are not available. Patients with neuromuscular diseases represent a large portion of it. Research questions: Specific research questions are formulated and answered concerning the dimensions of medicine/nursing, economics, social, ethical and legal aspects. Beyond the technical aspect of the invasive home, mechanical ventilation, medical questions also deal with the patient’s symptoms and clinical signs as well as the frequency of complications. Economic questions pertain to the composition of costs and the differences to other ways of homecare concerning costs and quality of care. Questions regarding social aspects consider the health-related quality of life of patients and caregivers. Additionally, the ethical aspects connected to the decision of home mechanical ventilation are viewed. Finally, legal aspects of financing invasive home mechanical ventilation are discussed. Methods: Based on a systematic literature search in 2008 in a total of 31 relevant databases current literature is viewed and selected by means of fixed criteria. Randomized controlled studies, systematic reviews and HTA reports (health technology assessment, clinical studies with patient numbers above ten, health-economic evaluations, primary studies with particular cost analyses and quality-of-life studies related to the research questions are included in the analysis. Results and discussion: Invasive mechanical ventilation may improve symptoms of hypoventilation, as the analysis of the literature shows. An increase in life expectancy is likely, but for ethical reasons it is not confirmed by premium-quality studies. Complications (e. g. pneumonia are rare

  10. Time course and dimensions of postural control changes following neuromuscular training in youth field hockey athletes

    NARCIS (Netherlands)

    Zech, Astrid; Klahn, Philipp; Hoeft, Jon; Eulenburg, Christine Zu; Steib, Simon

    2014-01-01

    Purpose Injury prevention effects of neuromuscular training have been partly attributed to postural control adaptations. Uncertainty exists regarding the magnitude of these adaptations and on how they can be adequately monitored. The objective was to determine the time course of neuromuscular traini

  11. Cause of exercise associated muscle cramps (EAMC)--altered neuromuscular control, dehydration or electrolyte depletion?

    Science.gov (United States)

    Schwellnus, M P

    2009-06-01

    Exercise Associated Muscle Cramps (EAMC) is one of the most common conditions that require medical attention during or immediately after sports events. Despite the high prevalence of this condition the aetiology of EAMC in athletes is still not well understood. The purpose of this review is to examine current scientific evidence in support of (1) the "electrolyte depletion" and "dehydration" hypotheses and (2) the "altered neuromuscular control" hypothesis in the aetiology of EAMC. In this review, scientific evidence will, as far as possible, be presented using evidence-based medicine criteria. This is particularly relevant in this field, as the quality of experimental methodology varies considerably among studies that are commonly cited in support of hypotheses to explain the aetiology of EAMC. Scientific evidence in support of the "electrolyte depletion" and "dehydration" hypotheses for the aetiology of EAMC comes mainly from anecdotal clinical observations, case series totalling 18 cases, and one small (n = 10) case-control study. Results from four prospective cohort studies do not support these hypotheses. In addition, the "electrolyte depletion" and "dehydration" hypotheses do not offer plausible pathophysiological mechanisms with supporting scientific evidence that could adequately explain the clinical presentation and management of EAMC. Scientific evidence for the "altered neuromuscular control" hypothesis is based on evidence from research studies in human models of muscle cramping, epidemiological studies in cramping athletes, and animal experimental data. Whilst it is clear that further evidence to support the "altered neuromuscular control" hypothesis is also required, research data are accumulating that support this as the principal pathophysiological mechanism for the aetiology of EAMC.

  12. The use of “stabilization exercises” to affect neuromuscular control in the lumbopelvic region: a narrative review

    Science.gov (United States)

    Bruno, Paul

    2014-01-01

    It is well-established that the coordination of muscular activity in the lumbopelvic region is vital to the generation of mechanical spinal stability. Several models illustrating mechanisms by which dysfunctional neuromuscular control strategies may serve as a cause and/or effect of low back pain have been described in the literature. The term “core stability” is variously used by clinicians and researchers, and this variety has led to several rehabilitative approaches suggested to affect the neuromuscular control strategies of the lumbopelvic region (e.g. “stabilization exercise”, “motor control exercise”). This narrative review will highlight: 1) the ongoing debate in the clinical and research communities regarding the terms “core stability” and “stabilization exercise”, 2) the importance of sub-grouping in identifying those patients most likely to benefit from such therapeutic interventions, and 3) two protocols that can assist clinicians in this process. PMID:24932016

  13. The role of neuromuscular changes in aging and knee osteoarthritis on dynamic postural control.

    Science.gov (United States)

    Takacs, Judit; Carpenter, Mark G; Garland, S Jayne; Hunt, Michael A

    2013-04-01

    Knee osteoarthritis (OA) is a chronic joint condition, with 30% of those over the age of 75 exhibiting severe radiographic disease. Nearly 50% of those with knee OA have experienced a fall in the past year. Falls are a considerable public health concern, with a high risk of serious injury and a significant socioeconomic impact. The ability to defend against a fall relies on adequate dynamic postural control, and alterations in dynamic postural control are seen with normal aging. Neuromuscular changes associated with aging may be responsible for some of these alterations in dynamic postural control. Even greater neuromuscular deficits, which may impact dynamic postural control and the ability to defend against a fall, are seen in people with knee OA. There is little evidence to date on how knee OA affects the ability to respond to and defend against falls and the neuromuscular changes that contribute to balance deficits. As a result, this review will: summarize the key characteristics of postural responses to an external perturbation, highlight the changes in dynamic postural control seen with normal aging, review the neuromuscular changes associated with aging that have known and possible effects on dynamic postural control, and summarize the neuromuscular changes and balance problems in knee OA. Future research to better understand the role of neuromuscular changes in knee OA and their effect on dynamic postural control will be suggested. Such an understanding is critical to the successful creation and implementation of fall prevention and treatment programs, in order to reduce the excessive risk of falling in knee OA.

  14. Propiocepción y control neuromuscular en el fútblo infantil

    OpenAIRE

    Zarza, Cristían

    2014-01-01

    En el fútbol profesional la escasa utilización de la pierna no hábil hace que muchas situaciones de juego no se resuelvan eficazmente, además de predisponer a la aparición de lesiones. El presente estudio se concentró en determinar la influencia del entrenamiento propioceptivo y del control neuromuscular en las cualidades físicas y técnicas del miembro no hábil. Objetivo: Indagar el nivel propioceptivo y de control neuromuscular del miembro inferior no hábil en chicos que re...

  15. Acceleromyography and mechanomyography for establishing potency of neuromuscular blocking agents: a randomized-controlled trial

    DEFF Research Database (Denmark)

    Claudius, C; Viby-Mogensen, J; Skovgaard, Lene Theil

    2009-01-01

    and opioid. Neuromuscular blockade was induced with rocuronium 100, 150, 200 or 250 microg/kg. Neuromuscular monitoring was performed with AMG (TOF-Watch SX) with pre-load (Hand Adapter) at one arm and MMG (modified TOF-Watch SX) on the other, using 0.1 Hz single twitch stimulation. Dose......) for this purpose. The aim of this study was to compare AMG and MMG for establishing dose-response relationship and potency, using rocuronium as an example. METHODS: We included 40 adult patients in this randomized-controlled single-dose response study. Anaesthesia was induced and maintained with propofol...

  16. Valoració i entrenament del control neuromuscular per a la millora del rendiment esportiu

    OpenAIRE

    Fort Vanmeerhaeghe, Azahara

    2010-01-01

    El control neuromuscular ha estat descrit com un important factor per a l'èxit en el rendiment esportiu. De la mateixa manera, també s'ha identificat com a clau en la prevenció i readaptació de les lesions esportives. El principal objectiu d'aquesta tesi doctoral és avaluar l'eficàcia de diferents tipus d'entrenament neuromuscular en esportistes.S'ha utilitzat una mostra de 81 esportistes sans entre els diferents estudis que s'hi presenten. Les diferents avaluacions realitzades han registrat ...

  17. Mechanical and neuromuscular changes with lateral trunk lean gait modifications.

    Science.gov (United States)

    Robbins, Shawn M; Teoli, Anthony; Preuss, Richard A

    2016-09-01

    Lateral trunk lean (LTL) is a proposed intervention for knee osteoarthritis but increased muscular demands have not been considered. The objective was to compare lower extremity and trunk muscle activation and joint mechanics between normal and increased LTL gait in healthy adults. Participants (n=20, mean age 22 years) were examined under two gait conditions: normal and increased LTL. A motion capture system and force plates sampled at 100 and 2000Hz respectively were used to determine joint angles and external moments including LTL angle and external knee adduction moment (KAM). Surface electromyography, sampled at 2000Hz, measured activation of six trunk/hip muscles bilaterally. Peak LTL angle, peak KAM, gait speed, and mean values from electromyography waveforms were compared between normal and LTL conditions using paired t-tests or 2-way analysis of variance. There was a significant (p<0.05) increase in peak LTL angle, decrease in first but not second peak KAM, and decrease in gait speed during LTL gait. There were significant (p<0.01) increases in external oblique and iliocostalis muscle activation during LTL gait. There was no change in activation for internal oblique, rectus abdominis, longissimus, and gluteus medius. LTL gait decreased early/mid-stance KAM demonstrating its ability to decrease medial compartment knee loading. Increases in external oblique and iliocostalis activation were present but small to moderate in size and unlikely to lead to short term injury. Longitudinal studies should evaluate the effectiveness of increased LTL for knee osteoarthritis and if the increase in muscular demands leads to negative long term side effects.

  18. Hormonal and neuromuscular responses to mechanical vibration applied to upper extremity muscles.

    Directory of Open Access Journals (Sweden)

    Riccardo Di Giminiani

    Full Text Available OBJECTIVE: To investigate the acute residual hormonal and neuromuscular responses exhibited following a single session of mechanical vibration applied to the upper extremities among different acceleration loads. METHODS: Thirty male students were randomly assigned to a high vibration group (HVG, a low vibration group (LVG, or a control group (CG. A randomized double-blind, controlled-parallel study design was employed. The measurements and interventions were performed at the Laboratory of Biomechanics of the University of L'Aquila. The HVG and LVG participants were exposed to a series of 20 trials ×10 s of synchronous whole-body vibration (WBV with a 10-s pause between each trial and a 4-min pause after the first 10 trials. The CG participants assumed an isometric push-up position without WBV. The outcome measures were growth hormone (GH, testosterone, maximal voluntary isometric contraction during bench-press, maximal voluntary isometric contraction during handgrip, and electromyography root-mean-square (EMGrms muscle activity (pectoralis major [PM], triceps brachii [TB], anterior deltoid [DE], and flexor carpi radialis [FCR]. RESULTS: The GH increased significantly over time only in the HVG (P = 0.003. Additionally, the testosterone levels changed significantly over time in the LVG (P = 0.011 and the HVG (P = 0.001. MVC during bench press decreased significantly in the LVG (P = 0.001 and the HVG (P = 0.002. In the HVG, the EMGrms decreased significantly in the TB (P = 0.006 muscle. In the LVG, the EMGrms decreased significantly in the DE (P = 0.009 and FCR (P = 0.006 muscles. CONCLUSION: Synchronous WBV acutely increased GH and testosterone serum concentrations and decreased the MVC and their respective maximal EMGrms activities, which indicated a possible central fatigue effect. Interestingly, only the GH response was dependent on the acceleration with respect to the subjects' responsiveness.

  19. Fatiguing exercise intensity influences the relationship between parameters reflecting neuromuscular function and postural control variables.

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    Sébastien Boyas

    Full Text Available The purpose of this study was to investigate the influence of fatiguing exercise intensity on the nature and extent of fatigue-induced changes in neuromuscular function and postural stability in quiet standing. We also explored the contribution of selected neuromuscular mechanisms involved in force production to postural stability impairment observed following fatigue using an approach based on multivariate regressions. Eighteen young subjects performed 30-s postural trials on one leg with their eyes closed. Postural trials were performed before and after fatiguing exercises of different intensities: 25, 50 and 75% of maximal isometric plantarflexor torque. Fatiguing exercises consisted of sustaining a plantarflexor isometric contraction at the target intensity until task failure. Maximal isometric plantarflexor torque, electromyographic activity of plantarflexor and dorsiflexor muscles, activation level (twitch interpolation technique and twitch contractile properties of plantarflexors were used to characterize neuromuscular function. The 25% exercise was associated with greater central fatigue whereas the 50 and 75% exercises involved mostly peripheral fatigue. However, all fatiguing exercises induced similar alterations in postural stability, which was unexpected considering previous literature. Stepwise multiple regression analyses showed that fatigue-related changes in selected parameters related to neuromuscular function could explain more than half (0.51≤R(2≤0.82 of the changes in postural variables for the 25% exercise. On the other hand, regression models were less predictive (0.17≤R(2≤0.73 for the 50 and 75% exercises. This study suggests that fatiguing exercise intensity does not influence the extent of postural stability impairment, but does influence the type of fatigue induced and the neuromuscular function predictors explaining changes in postural variables.

  20. Speed adaptation in a powered transtibial prosthesis controlled with a neuromuscular model

    Science.gov (United States)

    Markowitz, Jared; Krishnaswamy, Pavitra; Eilenberg, Michael F.; Endo, Ken; Barnhart, Chris; Herr, Hugh

    2011-01-01

    Control schemes for powered ankle–foot prostheses would benefit greatly from a means to make them inherently adaptive to different walking speeds. Towards this goal, one may attempt to emulate the intact human ankle, as it is capable of seamless adaptation. Human locomotion is governed by the interplay among legged dynamics, morphology and neural control including spinal reflexes. It has been suggested that reflexes contribute to the changes in ankle joint dynamics that correspond to walking at different speeds. Here, we use a data-driven muscle–tendon model that produces estimates of the activation, force, length and velocity of the major muscles spanning the ankle to derive local feedback loops that may be critical in the control of those muscles during walking. This purely reflexive approach ignores sources of non-reflexive neural drive and does not necessarily reflect the biological control scheme, yet can still closely reproduce the muscle dynamics estimated from biological data. The resulting neuromuscular model was applied to control a powered ankle–foot prosthesis and tested by an amputee walking at three speeds. The controller produced speed-adaptive behaviour; net ankle work increased with walking speed, highlighting the benefits of applying neuromuscular principles in the control of adaptive prosthetic limbs. PMID:21502131

  1. Effect of jumping interval training on neuromuscular and physiological parameters: a randomized controlled study.

    Science.gov (United States)

    Ache-Dias, Jonathan; Dellagrana, Rodolfo A; Teixeira, Anderson S; Dal Pupo, Juliano; Moro, Antônio R P

    2016-01-01

    This study analyzed the effect of 4 weeks of jumping interval training (JIT), included in endurance training, on neuromuscular and physiological parameters. Eighteen recreational runners, randomized in control and experimental groups, performed 40 min of running at 70% of velocity at peak oxygen uptake, for 3 times per week. Additionally, the experimental group performed the JIT twice per week, which consisted of 4 to 6 bouts of continuous vertical jumps (30 s) with 5-min intervals. Three days before and after the training period, the countermovement (CMJ) and continuous jump (CJ30), isokinetic and isometric evaluation of knee extensors/flexors, progressive maximal exercise, and submaximal constant-load exercise were performed. The JIT provoked improvement in neuromuscular performance, indicated by (i) increased jump height (4.7%; effect size (ES) = 0.99) and power output (≈ 3.7%; ES ≈ 0.82) of CMJ and rate of torque development of knee extensors in isometric contraction (29.5%; ES = 1.02); (ii) anaerobic power and capacity, represented by the mean of jump height (7.4%; ES = 0.8), and peak power output (PPO) (5.6%; ES = 0.73) of the first jumps of CJ30 and the mean of jump height (10.2%, ES = 1.04) and PPO (9.5%, ES = 1.1), considering all jumps of CJ30; and (iii) aerobic power and capacity, represented by peak oxygen uptake (9.1%, ES = 1.28), velocity at peak oxygen uptake (2.7%, ES = 1.11), and velocity corresponding to the onset of blood lactate accumulation (9.7%, ES = 1.23). These results suggest that the JIT included in traditional endurance training induces moderate to large effects on neuromuscular and physiological parameters.

  2. Effects of regular Tai Chi practice and jogging on neuromuscular reaction during lateral postural control in older people.

    Science.gov (United States)

    Wang, Shao-Jun; Xu, Dong-Qing; Li, Jing-Xian

    2017-01-01

    This study examined the effects of regular Tai Chi practice and jogging on the neuromuscular activity of the trunk, hip, and ankle joint muscles of older people during lateral postural perturbation. A total of 42 older people participated in the study and formed the Tai Chi, jogging, and sedentary control groups. Electromyography signals were collected from the peroneus longus, anterior tibialis, gluteus medius, and erector spinae during unpredictable mediolateral perturbation. The Tai Chi group exhibited significantly faster latencies of the tibialis anterior and erector spinae than the control group. The jogging group showed a significantly shorter neuromuscular reaction time of the erector spinae than the control group. No significant difference was observed between the Tai Chi and jogging groups. Long-term regular Tai Chi practice enhanced the neuromuscular reaction of the erector spinae and tibialis anterior to lateral perturbation and will help timely posture correction when lateral postural distributions occur.

  3. The Effect of Neuromuscular Blockade on Oxygen Consumption and Energy Expenditure in Mechanically Ventilated Acute Respiratory Insufficiency Patients

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    Esra Yüksel

    2012-04-01

    Full Text Available Objective: The aim of this study is to investigate the effect of neuromuscular blockade on oxygen consumption and energy expenditure in sedated patients with acute respiratory failure who were followed under mechanical ventilation support. Material and Method: 21 acute respiratory failure patients under mechanical ventilation support were included in the study. All patients were sedated with propofol infusion to have a sedation level of 3 on the Ramsay scale. After adequate sedation and hemodynamic stability was achieved, baseline values of oxygen consumption, carbondioxide production and energy consumption of the patients were measured by indirect calorimetry device and recorded. Neuromuscular transmission was monitorized by TOF-Guard, and then 0,1 mg/kg bolus dose vecuronium was administered to the patients. When TOF 0, 25, 50, 90 values were obtained, oxygen, carbondioxide and energy consumption were measured by indirect calorimetry device and recorded. Results: No statistically significant difference were found between pre- and post-curarisation hemodynamic parameters, ventilation parameters, arterial blood gas values (p>0.05. A statistically significant decrease was observed between the oxygen consumption, carbondioxide production and energy consumption measured before curarisation and when TOF value was 0 (p0.05. Conclusion: It was concluded that the effect of neuromuscular blockage on reducing energy and oxygen consumption should be taken into consideration while calculating the daily energy need in intensive care in patients curarized at TOF 0 level. (Journal of the Turkish Society Intensive Care 2012; 10: 8-12

  4. Athletic background is related to superior trunk proprioceptive ability, postural control, and neuromuscular responses to sudden perturbations.

    Science.gov (United States)

    Glofcheskie, Grace O; Brown, Stephen H M

    2017-01-28

    Trunk motor control is essential for athletic performance, and inadequate trunk motor control has been linked to an increased risk of developing low back and lower limb injury in athletes. Research is limited in comparing relationships between trunk neuromuscular control, postural control, and trunk proprioception in athletes from different sporting backgrounds. To test for these relationships, collegiate level long distance runners and golfers, along with non-athletic controls were recruited. Trunk postural control was investigated using a seated balance task. Neuromuscular control in response to sudden trunk loading perturbations was measured using electromyography and kinematics. Proprioceptive ability was examined using active trunk repositioning tasks. Both athlete groups demonstrated greater trunk postural control (less centre of pressure movement) during the seated task compared to controls. Athletes further demonstrated faster trunk muscle activation onsets, higher muscle activation amplitudes, and less lumbar spine angular displacement in response to sudden trunk loading perturbations when compared to controls. Golfers demonstrated less absolute error and variable error in trunk repositioning tasks compared to both runners and controls, suggestive of greater proprioceptive ability. This suggests an interactive relationship between neuromuscular control, postural control, and proprioception in athletes, and that differences exist between athletes of various training backgrounds.

  5. Comparison of Twitch Responses During Current- or Voltage-Controlled Transcutaneous Neuromuscular Electrical Stimulation.

    Science.gov (United States)

    Vargas Luna, José Luis; Krenn, Matthias; Löfler, Stefan; Kern, Helmut; Cortés R, Jorge A; Mayr, Winfried

    2015-10-01

    Neuromuscular electrical stimulation (NMES) is an established method for functional restoration of muscle function, rehabilitation, and diagnostics. In this work, NMES was applied with surface electrodes placed on the anterior thigh to identify the main differences between current-controlled (CC) and voltage-controlled (VC) modes. Measurements of the evoked knee extension force and the myoelectric signal of quadriceps and hamstrings were taken during stimulation with different amplitudes, pulse widths, and stimulation techniques. The stimulation pulses were rectangular and symmetric biphasic for both stimulation modes. The electrode-tissue impedance influences the differences between CC and VC stimulation. The main difference is that for CC stimulation, variation of pulse width and amplitude influences the amount of nerve depolarization, whereas VC stimulation is only dependent on amplitude variations for pulse widths longer than 150 μs. An important remark is that these findings are strongly dependent on the characteristics of the electrode-skin interface. In our case, we used large stimulation electrodes placed on the anterior thigh, which cause higher capacitive effects. The controllability, voltage compliance, and charge characteristics of each stimulation technique should be considered during the stimulators design. For applications that require the activation of a large amount of nerve fibers, VC is a more suitable option. In contrast, if the application requires a high controllability, then CC should be chosen prior to VC.

  6. The Role of Musculoskeletal Dynamics and Neuromuscular Control in Stress Development in Bone

    Science.gov (United States)

    DeWoody, Yssa

    1996-01-01

    The role of forces produced by the musculotendon units in the stress development of the long bones during gait has not been fully analyzed. It is well known that the musculotendons act as actuators producing the joint torques which drive the body. Although the joint torques required to perform certain motor tasks can be recovered through a kinematic analysis, it remains a difficult problem to determine the actual forces produced by each muscle that resulted in these torques. As a consequence, few studies have focused on the role of individual muscles in the development of stress in the bone. This study takes a control theoretic approach to the problem. A seven-link, eight degrees of freedom model of the body is controlled by various muscle groups on each leg to simulate gait. The simulations incorporate Hill-type models of muscles with activation and contraction dynamics controlled through neural inputs. This direct approach allows one to know the exact muscle forces exerted by each musculotendon throughout the gait cycle as well the joint torques and reaction forces at the ankle and knee. Stress and strain computed by finite element analysis on skeletal members will be related to these derived loading conditions. Thus the role of musculoskeletal dynamics and neuromuscular control in the stress development of the tibia during gait can be analyzed.

  7. Control of a powered ankle-foot prosthesis based on a neuromuscular model.

    Science.gov (United States)

    Eilenberg, Michael F; Geyer, Hartmut; Herr, Hugh

    2010-04-01

    Control schemes for powered ankle-foot prostheses rely upon fixed torque-ankle state relationships obtained from measurements of intact humans walking at target speeds and across known terrains. Although effective at their intended gait speed and terrain, these controllers do not allow for adaptation to environmental disturbances such as speed transients and terrain variation. Here we present an adaptive muscle-reflex controller, based on simulation studies, that utilizes an ankle plantar flexor comprising a Hill-type muscle with a positive force feedback reflex. The model's parameters were fitted to match the human ankle's torque-angle profile as obtained from level-ground walking measurements of a weight and height-matched intact subject walking at 1 m/s. Using this single parameter set, clinical trials were conducted with a transtibial amputee walking on level ground, ramp ascent, and ramp descent conditions. During these trials, an adaptation of prosthetic ankle work was observed in response to ground slope variation, in a manner comparable to intact subjects, without the difficulties of explicit terrain sensing. Specifically, the energy provided by the prosthesis was directly correlated to the ground slope angle. This study highlights the importance of neuromuscular controllers for enhancing the adaptiveness of powered prosthetic devices across varied terrain surfaces.

  8. Acute effect of scapular proprioceptive neuromuscular facilitation (PNF) techniques and classic exercises in adhesive capsulitis: a randomized controlled trial.

    Science.gov (United States)

    Balcı, Nilay Comuk; Yuruk, Zeliha Ozlem; Zeybek, Aslican; Gulsen, Mustafa; Tekindal, Mustafa Agah

    2016-04-01

    [Purpose] The aim of our study was to compare the initial effects of scapular proprioceptive neuromuscular facilitation techniques and classic exercise interventions with physiotherapy modalities on pain, scapular dyskinesis, range of motion, and function in adhesive capsulitis. [Subjects and Methods] Fifty-three subjects were allocated to 3 groups: scapular proprioceptive neuromuscular facilitation exercies and physiotherapy modalities, classic exercise and physiotherapy modalities, and only physiotherapy modalities. The intervention was applied in a single session. The Visual Analog Scale, Lateral Scapular Slide Test, range of motion and Simple Shoulder Test were evaluated before and just after the one-hour intervention in the same session (all in one session). [Results] All of the groups showed significant differences in shoulder flexion and abduction range of motion and Simple Shoulder Test scores. There were statistically significant differences in Visual Analog Scale scores in the proprioceptive neuromuscular facilitation and control groups, and no treatment method had significant effect on the Lateral Scapular Slide Test results. There were no statistically significant differences between the groups before and after the intervention. [Conclusion] Proprioceptive neuromuscular facilitation, classic exercise, and physiotherapy modalities had immediate effects on adhesive capsulitis in our study. However, there was no additional benefit of exercises in one session over physiotherapy modalities. Also, an effective treatment regimen for shoulder rehabilitation of adhesive capsulitis patients should include scapular exercises.

  9. An investigation into the neuromuscular control at the level of the upper limbs of junior handball girls players

    Directory of Open Access Journals (Sweden)

    Teodora-Mihaela Iconomescu

    2016-01-01

    Full Text Available In this paper we want to present the development of upper limb muscle control in sportswomen handball. Thus at the beginning and end of championship players girls were tested with one MOVE 1 DU device type, then centralized data obtained and analyzed statistically. Handball players’ were 10 girls subjected search with the average age of 12.5 years, the average height of 165.5 cm. and an average weight of 57.7 kg. By centralizing data obtained we have seen an increase in upper limb neuromuscular control in final testing of statistically p <.05. Statistical analysis confirms the hypothesis that the means to improve neuromuscular control if applied properly and psychomotor functional somatic features specific age increases the competitive performance.

  10. Laminins promote postsynaptic maturation by an autocrine mechanism at the neuromuscular junction

    OpenAIRE

    Nishimune, Hiroshi; Jarad, George; Moulson, Casey L.; Müller, Ulrich; Miner, Jeffrey H.; Valdez, Gregorio; Sanes, Joshua R

    2008-01-01

    A prominent feature of synaptic maturation at the neuromuscular junction (NMJ) is the topological transformation of the acetylcholine receptor (AChR)-rich postsynaptic membrane from an ovoid plaque into a complex array of branches. We show here that laminins play an autocrine role in promoting this transformation. Laminins containing the α4, α5, and β2 subunits are synthesized by muscle fibers and concentrated in the small portion of the basal lamina that passes through the synaptic cleft at ...

  11. Adaptive control of functional neuromuscular stimulation-induced knee extension exercise.

    Science.gov (United States)

    Ezenwa, B N; Glaser, R M; Couch, W; Figoni, S F; Rodgers, M M

    1991-01-01

    An automated system for exercising the paralyzed quadriceps muscles of spinal cord injured patients using functional neuromuscular stimulation (FNS) has been developed. It induces smooth concentric and eccentric contractions in both limbs to enable bilateral 70 degree knee extensions in an asynchronous pattern. External load resistance is applied at the ankle level to "overload" the muscles and bring about training effects. The system uses adaptive control methods to adjust FNS current output (threshold level and the ramp slope) to the quadriceps muscles to maintain performance as the muscles fatigue. Feedback control signals for limb movement and knee extension angle are used to continuously adjust the FNS current parameters so that the external load is moved through the preset zero to 70 degree angle range. Typically, the threshold current level and the FNS current increase as the muscles fatigue to maintain performance with repetitive contractions. Fatigue is defined as the inability to extend the knee to 50 percent of the 70 degree target angle. When this occurs, FNS is automatically terminated for the fatigued leg, while the functioning leg continues to exercise. The automated nature of this system appears to be advantageous as compared to a manually operated system for subject safety, convenience, and uniformity of exercise bouts. Simulated safety problems, such as hyperextension of the knee joint, open circuitry, muscle spasms, and low battery power, were successfully detected by the logic circuitry, and the system followed appropriate safety procedures to minimize risk.

  12. EEG controlled neuromuscular electrical stimulation of the upper limb for stroke patients

    Science.gov (United States)

    Tan, Hock Guan; Shee, Cheng Yap; Kong, Keng He; Guan, Cuntai; Ang, Wei Tech

    2011-03-01

    This paper describes the Brain Computer Interface (BCI) system and the experiments to allow post-acute (neuromuscular electrical stimulation (NMES)-assisted extension of the wrist/fingers, which are essential pre-requisites for useful hand function. EEG was recorded while subjects performed motor imagery of their paretic limb, and then analyzed to determine the optimal frequency range within the mu-rhythm, with the greatest attenuation. Aided by visual feedback, subjects then trained to regulate their mu-rhythm EEG to operate the BCI to trigger NMES of the wrist/finger. 6 post-acute stroke patients successfully completed the training, with 4 able to learn to control and use the BCI to initiate NMES. This result is consistent with the reported BCI literacy rate of healthy subjects. Thereafter, without the loss of generality, the controller of the NMES is developed and is based on a model of the upper limb muscle (biceps/triceps) groups to determine the intensity of NMES required to flex or extend the forearm by a specific angle. The muscle model is based on a phenomenological approach, with parameters that are easily measured and conveniently implemented.

  13. Effects of footwear comfort perception on the neuromuscular control of balance.

    Science.gov (United States)

    Burke, Jeanmarie R

    2012-04-01

    The purpose of this research was to determine the effects of footwear comfort perception on the gain of the gastrocnemius H-reflex response during single leg balance tasks. Subjects performed single leg balance tasks while wearing aerobic sneakers with two different pairs of shoe insoles that were subjectively rated for comfort using a reliable 150 mm visual analog scale. The primary outcome was the consistency of decreasing the gain of the gastrocnemius H-reflex with increasing balance task complexity as a function of footwear comfort perception. Among the asymptomatic subjects (n = 11), H-reflex gain significantly decreased by 19% and 10% from balancing on a stable surface to an unstable surface for the shoe-brand and replacement insoles, respectively (p < .05). Among the subjects with musculoskeletal disorders (n = 13), H-reflex gain significantly decreased by 10% from balancing on a stable surface to an unstable surface when wearing custom-molded foot orthotics, but H-reflex gain significantly increased by 27% from balancing on a stable surface to an unstable surface when wearing replacement insoles (p < .05). Decreases in footwear comfort perception may negatively impact the attenuation of gastrocnemius H-reflex gain that contributes to the neuromuscular control of challenging balance tasks.

  14. Feedback control of arm movements using Neuro-Muscular Electrical Stimulation (NMES) combined with a lockable, passive exoskeleton for gravity compensation

    OpenAIRE

    Christian eKlauer; Thomas eSchauer; Werner eReichenfelser; Jakob eKarner; Sven eZwicker; Marta eGandolla; Emilia eAmbrosini; Simona eFerrante; Marco eHack; Andreas eJedlitschka; Alexander eDuschau-Wicke; Margit eGfoehler; Alessandra ePedrocchi

    2014-01-01

    Within the European project MUNDUS, an assistive framework was developed for the support of arm and hand functions during daily life activities in severely impaired people. Potential users of this system are patients with high-level spinal cord injury and neurodegenerative neuromuscular diseases, such as amyotrophic lateral sclerosis, Friedreich ataxia, and multiple sclerosis. This contribution aims at designing a feedback control system for Neuro-Muscular Electrical Stimulation (NMES) to ena...

  15. Neuromuscular blockade in children Bloqueadores neuromusculares em crianças

    Directory of Open Access Journals (Sweden)

    João Fernando Lourenço de Almeida

    2000-06-01

    Full Text Available Neuromuscular blocking agents (NMBAs have been widely used to control patients who need to be immobilized for some kind of medical intervention, such as an invasive procedure or synchronism with mechanical ventilation. The purpose of this monograph is to review the pharmacology of the NMBAs, to compare the main differences between the neuromuscular junction in neonates, infants, toddlers and adults, and moreover to discuss their indications in critically ill pediatric patients. Continuous improvement of knowledge about NMBAs pharmacology, adverse effects, and the many other remaining unanswered questions about neuromuscular junction and neuromuscular blockade in children is essential for the correct use of these drugs. Therefore, the indication of these agents in pediatrics is determined with extreme judiciousness. Computorized (Medline 1990-2000 and active search of articles were the mechanisms used in this review.Os bloqueadores neuromusculares têm sido amplamente utilizados para controlar pacientes que necessitem imobilidade para algum tipo de intervenção médica, desde a realização de procedimentos invasivos até a obtenção de sincronismo com a ventilação mecânica. O objetivo básico desta monografia é revisar a farmacologia dos principais bloqueadores neuromusculares, analisar as diferenças existentes na junção neuromuscular de neonatos, lactentes, pré-escolares e adultos, além de discutir suas indicações em pacientes criticamente enfermos internados em unidade de terapia intensiva pediátrica. Revisão computadorizada da literatura (Medline 1990-2000 associado a busca ativa de artigos compuseram o mecanismo de busca dos dados desta revisão.

  16. No Neuromuscular Side-Effects of Scopolamine in Sensorimotor Control and Force-Generating Capacity Among Parabolic Fliers

    Science.gov (United States)

    Ritzmann, Ramona; Freyler, Kathrin; Krause, Anne; Gollhofer, Albert

    2016-10-01

    Scopolamine is used to counteract motion sickness in parabolic flight (PF) experiments. Although the drug's anticholinergic properties effectively impede vomiting, recent studies document other sensory side-effects in the central nervous system that may considerably influence sensorimotor performance. This study aimed to quantify such effects in order to determine if they are of methodological and operational significance for sensorimotor control. Ten subjects of a PF campaign received a weight-sex-based dose of a subcutaneous scopolamine injection. Sensorimotor performance was recorded before medication, 20min, 2h and 4h after injection in four space-relevant paradigms: balance control in one-leg stance with eyes open (protocol 1) and closed as well as force-generating capacity in countermovement jumps and hops (protocol 2). Postural sway, forces and joint angles were recorded. Neuromuscular control was assessed by electromyography and peripheral nerve stimulation; H-reflexes and M-waves were used to monitor spinal excitability of the Ia afferent reflex circuitry and maximal motor output. (1) H-reflex amplitudes, latencies and functional reflexes remained unchanged after scopolamine injection. (2) M-waves, neuromuscular activation intensities and antagonistic muscle coordination did not change with scopolamine administration. (3) Balance performance and force-generating capacity were not impeded by scopolamine. We found no evidence for changes in sensorimotor control in response to scopolamine injection. Sensory processing of daily relevant reflexes, spinal excitability, maximal motor output and performance parameters were not sensitive to the medication. We conclude that scopolamine administration can be used to counteract motion sickness in PF without methodological and operational concerns or interference regarding sensorimotor skills associated with neuromuscular control.

  17. Hybrid Neuroprosthesis for the Upper Limb: Combining Brain-Controlled Neuromuscular Stimulation with a Multi-Joint Arm Exoskeleton.

    Science.gov (United States)

    Grimm, Florian; Walter, Armin; Spüler, Martin; Naros, Georgios; Rosenstiel, Wolfgang; Gharabaghi, Alireza

    2016-01-01

    Brain-machine interface-controlled (BMI) neurofeedback training aims to modulate cortical physiology and is applied during neurorehabilitation to increase the responsiveness of the brain to subsequent physiotherapy. In a parallel line of research, robotic exoskeletons are used in goal-oriented rehabilitation exercises for patients with severe motor impairment to extend their range of motion (ROM) and the intensity of training. Furthermore, neuromuscular electrical stimulation (NMES) is applied in neurologically impaired patients to restore muscle strength by closing the sensorimotor loop. In this proof-of-principle study, we explored an integrated approach for providing assistance as needed to amplify the task-related ROM and the movement-related brain modulation during rehabilitation exercises of severely impaired patients. For this purpose, we combined these three approaches (BMI, NMES, and exoskeleton) in an integrated neuroprosthesis and studied the feasibility of this device in seven severely affected chronic stroke patients who performed wrist flexion and extension exercises while receiving feedback via a virtual environment. They were assisted by a gravity-compensating, seven degree-of-freedom exoskeleton which was attached to the paretic arm. NMES was applied to the wrist extensor and flexor muscles during the exercises and was controlled by a hybrid BMI based on both sensorimotor cortical desynchronization (ERD) and electromyography (EMG) activity. The stimulation intensity was individualized for each targeted muscle and remained subthreshold, i.e., induced no overt support. The hybrid BMI controlled the stimulation significantly better than the offline analyzed ERD (p = 0.028) or EMG (p = 0.021) modality alone. Neuromuscular stimulation could be well integrated into the exoskeleton-based training and amplified both the task-related ROM (p = 0.009) and the movement-related brain modulation (p = 0.019). Combining a hybrid BMI with neuromuscular stimulation

  18. Neuromuscular control of scapula muscles during a voluntary task in subjects with Subacromial Impingement Syndrome

    DEFF Research Database (Denmark)

    Larsen, C M; Søgaard, Karen; Chreiteh, S S;

    2013-01-01

    Imbalance of neuromuscular activity in the scapula stabilizers in subjects with Subacromial Impingement Syndrome (SIS) is described in restricted tasks and specific populations. Our aim was to compare the scapular muscle activity during a voluntary movement task in a general population...... with and without SIS (n=16, No-SIS=15). Surface electromyography was measured from Serratus anterior (SA) and Trapezius during bilateral arm elevation (no-load, 1kg, 3kg). Mean relative muscle activity was calculated for SA and the upper (UT) and lower part of trapezius (LWT), in addition to activation ratio...... and time to activity onset. In spite of a tendency to higher activity among SIS 0.10-0.30 between-group differences were not significant neither in ratio of muscle activation 0.80-0.98 nor time to activity onset 0.53-0.98. The hypothesized between-group differences in neuromuscular activity of Trapezius...

  19. Static balance and function in children with cerebral palsy submitted to neuromuscular block and neuromuscular electrical stimulation: Study protocol for prospective, randomized, controlled trial

    Directory of Open Access Journals (Sweden)

    Kazon Soráia

    2012-05-01

    Full Text Available Abstract Background The use of botulinum toxin A (BT-A for the treatment of lower limb spasticity is common in children with cerebral palsy (CP. Following the administration of BT-A, physical therapy plays a fundamental role in potentiating the functionality of the child. The balance deficit found in children with CP is mainly caused by muscle imbalance (spastic agonist and weak antagonist. Neuromuscular electrical stimulation (NMES is a promising therapeutic modality for muscle strengthening in this population. The aim of the present study is to describe a protocol for a study aimed at analyzing the effects of NMES on dorsiflexors combined with physical therapy on static and functional balance in children with CP submitted to BT- A. Methods/Design Protocol for a prospective, randomized, controlled trial with a blinded evaluator. Eligible participants will be children with cerebral palsy (Levels I, II and III of the Gross Motor Function Classification System between five and 12 years of age, with independent gait with or without a gait-assistance device. All participants will receive BT-A in the lower limbs (triceps surae. The children will then be randomly allocated for either treatment with motor physical therapy combined with NMES on the tibialis anterior or motor physical therapy alone. The participants will be evaluated on three occasions: 1 one week prior to the administration of BT-A; 2 one week after the administration of BT-A; and 3 four months after the administration of BT-A (end of intervention. Spasticity will be assessed by the Modified Ashworth Scale and Modified Tardieu Scale. Static balance will be assessed using the Medicapteurs Fusyo pressure platform and functional balance will be assessed using the Berg Balance Scale. Discussion The aim of this protocol study is to describe the methodology of a randomized, controlled, clinical trial comparing the effect of motor physical therapy combined with NMES on the tibialis anterior

  20. Mechanisms of hydrogen sulfide (H2S) action on synaptic transmission at the mouse neuromuscular junction.

    Science.gov (United States)

    Gerasimova, E; Lebedeva, J; Yakovlev, A; Zefirov, A; Giniatullin, R; Sitdikova, G

    2015-09-10

    Hydrogen sulfide (H2S) is a widespread gasotransmitter also known as a powerful neuroprotective agent in the central nervous system. However, the action of H2S in peripheral synapses is much less studied. In the current project we studied the modulatory effects of the H2S donor sodium hydrosulfide (NaHS) on synaptic transmission in the mouse neuromuscular junction using microelectrode technique. Using focal recordings of presynaptic response and evoked transmitter release we have shown that NaHS (300 μM) increased evoked end-plate currents (EPCs) without changes of presynaptic waveforms which indicated the absence of NaHS effects on sodium and potassium currents of motor nerve endings. Using intracellular recordings it was shown that NaHS increased the frequency of miniature end-plate potentials (MEPPs) without changing their amplitudes indicating a pure presynaptic effect. Furthermore, NaHS increased the amplitude of end-plate potentials (EPPs) without influencing the resting membrane potential of muscle fibers. L-cysteine, a substrate of H2S synthesis induced, similar to NaHS, an increase of EPC amplitudes whereas inhibitors of H2S synthesis (β-cyano-L-alanine and aminooxyacetic acid) had the opposite effect. Inhibition of adenylate cyclase using MDL 12,330A hydrochloride (MDL 12,330A) or elevation of cAMP level with 8-(4-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (pCPT-cAMP) completely prevented the facilitatory action of NaHS indicating involvement of the cAMP signaling cascade. The facilitatory effect of NaHS was significantly diminished when intracellular calcium (Ca(2+)) was buffered by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis acetoxymethyl ester (BAPTA-AM) and ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid acetoxymethyl ester (EGTA-AM). Activation of ryanodine receptors by caffeine or ryanodine increased acetylcholine release and prevented further action of NaHS on transmitter release, likely due to

  1. Mechanisms of short-term plasticity at neuromuscular active zones of Drosophila

    Science.gov (United States)

    Hallermann, Stefan; Heckmann, Manfred; Kittel, Robert J.

    2010-01-01

    During short bursts of neuronal activity, changes in the efficacy of neurotransmitter release are governed primarily by two counteracting processes: (1) Ca2+-dependent elevations of vesicle release probability and (2) depletion of synaptic vesicles. The dynamic interplay of both processes contributes to the expression of activity-dependent synaptic plasticity. Here, we exploited various facets of short-term plasticity at the Drosophila neuromuscular junction to dissect these two processes. This enabled us to rigorously analyze different models of synaptic vesicle pools in terms of their size and mobilization properties. Independent of the specific model, we estimate ∼300 readily releasable vesicles with an average release probability of ∼50% in 1 mM extracellular calcium (∼5% in 0.4 mM extracellular calcium) under resting conditions. The models also helped interpreting the altered short-term plasticity of the previously reported mutant of the active zone component Bruchpilot (BRP). Finally, our results were independently confirmed through fluctuation analysis. Our data reveal that the altered short-term plasticity observed in BRP mutants cannot be accounted for by delocalized Ca2+ channels alone and thus suggest an additional role of BRP in short-term plasticity. PMID:20811513

  2. Laminins promote postsynaptic maturation by an autocrine mechanism at the neuromuscular junction.

    Science.gov (United States)

    Nishimune, Hiroshi; Valdez, Gregorio; Jarad, George; Moulson, Casey L; Müller, Ulrich; Miner, Jeffrey H; Sanes, Joshua R

    2008-09-22

    A prominent feature of synaptic maturation at the neuromuscular junction (NMJ) is the topological transformation of the acetylcholine receptor (AChR)-rich postsynaptic membrane from an ovoid plaque into a complex array of branches. We show here that laminins play an autocrine role in promoting this transformation. Laminins containing the alpha4, alpha5, and beta2 subunits are synthesized by muscle fibers and concentrated in the small portion of the basal lamina that passes through the synaptic cleft at the NMJ. Topological maturation of AChR clusters was delayed in targeted mutant mice lacking laminin alpha5 and arrested in mutants lacking both alpha4 and alpha5. Analysis of chimeric laminins in vivo and of mutant myotubes cultured aneurally demonstrated that the laminins act directly on muscle cells to promote postsynaptic maturation. Immunohistochemical studies in vivo and in vitro along with analysis of targeted mutants provide evidence that laminin-dependent aggregation of dystroglycan in the postsynaptic membrane is a key step in synaptic maturation. Another synaptically concentrated laminin receptor, Bcam, is dispensable. Together with previous studies implicating laminins as organizers of presynaptic differentiation, these results show that laminins coordinate post- with presynaptic maturation.

  3. Management of Ventilatory Insufficiency in Neuromuscular Patients Using Mechanical Ventilator Supported by the Korean Government.

    Science.gov (United States)

    Kang, Seong-Woong; Choi, Won Ah; Cho, Han Eol; Lee, Jang Woo; Park, Jung Hyun

    2016-06-01

    Since 2001, financial support has been provided for all patients with neuromuscular disease (NMD) who require ventilatory support due to the paralysis of respiratory muscles in Korea. The purpose of this study was to identify ventilator usage status and appropriateness in these patients. We included 992 subjects with rare and incurable NMD registered for ventilator rental fee support. From 21 February 2011 to 17 January 2013, ventilator usage information, regular follow-up observation, and symptoms of chronic hypoventilation were surveyed by phone. Home visits were conducted for patients judged by an expert medical team to require medical examination. Abnormal ventilatory status was assessed by respiratory evaluation. Chronic respiratory insufficiency symptoms were reported by 169 of 992 subjects (17%), while 565 subjects (57%) did not receive regular respiratory evaluation. Ventilatory status was abnormal in 102 of 343 home-visit subjects (29.7%). Although 556 subjects (56%) reported 24-hour ventilator use, only 458 (46%) had an oxygen saturation monitoring device, and 305 (31%) performed an airstacking exercise. A management system that integrates ventilator usage monitoring, counselling and advice, and home visits for patients who receive ventilator support could improve the efficiency of the ventilator support project.

  4. Hybrid neuroprosthesis for the upper limb: combining brain-controlled neuromuscular stimulation with a multi-joint arm exoskeleton

    Directory of Open Access Journals (Sweden)

    Florian Grimm

    2016-08-01

    Full Text Available Brain-machine interface-controlled (BMI neurofeedback training aims to modulate cortical physiology and is applied during neurorehabilitation to increase the responsiveness of the brain to subsequent physiotherapy. In a parallel line of research, robotic exoskeletons are used in goal-oriented rehabilitation exercises for patients with severe motor impairment to extend their range of motion and the intensity of training. Furthermore, neuromuscular electrical stimulation (NMES is applied in neurologically impaired patients to restore muscle strength by closing the sensorimotor loop. In this proof-of-principle study, we explored an integrated approach for providing assistance as needed to amplify the task-related range of motion and the movement-related brain modulation during rehabilitation exercises of severely impaired patients. For this purpose, we combined these three approaches (BMI, NMES, and exoskeleton in an integrated neuroprosthesis and studied the feasibility of this device in seven severely affected chronic stroke patients who performed wrist flexion and extension exercises while receiving feedback via a virtual environment. They were assisted by a gravity-compensating, seven degree-of-freedom exoskeleton which was attached to the paretic arm. Neuromuscular electrical stimulation was applied to the wrist extensor and flexor muscles during the exercises and was controlled by a hybrid BMI based on both sensorimotor cortical desynchronization (ERD and electromyography (EMG activity. The stimulation intensity was individualized for each targeted muscle and remained subthreshold, i.e. induced no overt support. The hybrid BMI controlled the stimulation significantly better than the offline analyzed ERD (p=0.028 or EMG (p=0.021 modality alone. Neuromuscular stimulation could be well integrated into the exoskeleton-based training and amplified both the task-related range of motion (p=0.009 and the movement-related brain modulation (p=0

  5. Effects of proprioceptive neuromuscular facilitation neck pattern exercise on the ability to control the trunk and maintain balance in chronic stroke patients.

    Science.gov (United States)

    Hwangbo, Pil Neo; Don Kim, Kyoung

    2016-03-01

    [Purpose] The aim of this study was to investigate the effects of proprioceptive neuromuscular facilitation neck pattern exercise on the ability to control the trunk and balance in chronic stroke patients. [Subjects and Methods] A total of 30 study subjects were selected and randomly divided into an experimental group of 15 subjects, who received the proprioceptive neuromuscular facilitation neck pattern exercise, and a control group of 15 subjects, who received a traditional rehabilitation treatment. [Results] Statistically significant changes in all the items of the Trunk Impairment Scale, the Trunk Impairment Scale total score, and the Berg Balance Scale were observed in both the experimental group and the control group. significant between-group differences were found in all items among the subitems of the Trunk Impairment Scale except the static sitting balance. [Conclusion] Proprioceptive neuromuscular facilitation neck pattern exercise was shown to have a positive effect on increasing the ability to control the trunk and maintain balance in chronic stroke patients.

  6. Load Dependency of Postural Control--Kinematic and Neuromuscular Changes in Response to over and under Load Conditions.

    Directory of Open Access Journals (Sweden)

    Ramona Ritzmann

    Full Text Available Load variation is associated with changes in joint torque and compensatory reflex activation and thus, has a considerable impact on balance control. Previous studies dealing with over (OL and under loading (UL used water buoyancy or additional weight with the side effects of increased friction and inertia, resulting in substantially modified test paradigms. The purpose of this study was to identify gravity-induced load dependency of postural control in comparable experimental conditions and to determine the underlying neuromuscular mechanisms.Balance performance was recorded under normal loading (NL, 1 g, UL (0.16 g 0.38 g and OL (1.8 g in monopedal stance. Center of pressure (COP displacement and frequency distribution (low 0.15-0.5 Hz (LF, medium 0.5-2 Hz (MF, high 2-6 Hz (HF as well as ankle, knee and hip joint kinematics were assessed. Soleus spinal excitability was determined by H/M-recruitment curves (H/M-ratios.Compared to NL, OL caused an increase in ankle joint excursion, COP HF domain and H/M-ratio. Concomitantly, hip joint excursion and COP LF decreased. Compared to NL, UL caused modulations in the opposite direction: UL decreased ankle joint excursions, COP HF and H/M-ratio. Collaterally, hip joint excursion and COP LF increased. COP was augmented both in UL and in OL compared to NL.Subjects achieved postural stability in OL and UL with greater difficulty compared to NL. Reduced postural control was accompanied by modified balance strategies and compensatory reflex activation. With increasing load, a shift from hip to ankle strategy was observed. Accompanying, COP frequency distribution shifted from LF to HF and spinal excitability was enhanced. It is suggested that in OL, augmented ankle joint torques are compensated by quick reflex-induced postural reactions in distal muscles. Contrarily, UL is associated with diminished joint torques and thus, postural equilibrium may be controlled by the proximal segments to adjust the center of

  7. Neuromuscular hip biomechanics and pathology in the athlete.

    Science.gov (United States)

    Torry, Michael R; Schenker, Mara L; Martin, Hal D; Hogoboom, Doug; Philippon, Marc J

    2006-04-01

    Although hip arthroscopic techniques have been developed and evolved over the last 5 to 10 years to help active athletes, the mechanisms of athletic hip injuries across various sports are not well understood. The purpose of this article is to review the literature related to the osseous and ligamentous support as well as the neuromuscular control strategies associated with hip joint mechanics. The neuromuscular contributions to hip stability and mobility with respect to gait will be provided because this data represents the largest body of knowledge regarding hip function. Further, this article will present and describe probable mechanisms of injury in sporting activities most often associated with hip injury in the young athlete.

  8. Paraplegic standing controlled by functional neuromuscular stimulation: Part I--computer model and control-system design.

    Science.gov (United States)

    Khang, G; Zajac, F E

    1989-09-01

    We have developed a planar computer model to investigate paraplegic standing induced by functional neuromuscular stimulation. The model consists of nonlinear musculotendon dynamics (pulse train activation dynamics and musculotendon actuator dynamics), nonlinear body-segmental dynamics, and a linear output-feedback control law. The model of activation dynamics is an analytic expression that characterizes the relation between the stimulus parameters (pulse width and interpulse interval) and the muscle activation. Hill's classic two-element muscle model was modified into a musculotendon actuator model in order to account for the effects of submaximal activation and tendon elasticity on development of force by the actuator. The three body-segmental, multijoint model accounts for the anterior-posterior movements of the head and trunk, the thigh, and the shank. We modeled arm movement as an external disturbance and imposed the disturbance to the body-segmental dynamics by means of a quasistatic analysis. Linearization, and at times linear approximation of the computer model, enabled us to compute a constant, linear feedback-gain matrix, whose output is the net activation needed by a dynamical joint-torque actuator. Motivated by an assumption that minimization of energy expenditure lessens muscle fatigue, we developed an algorithm that then computes how to distribute the net activation among all the muscles crossing the joint. In part II, the combined feedback control strategy is applied to the nonlinear model of musculotendon and body-segmental dynamics to study how well the body ought to maintain balance should the feedback control strategy be employed.

  9. Ankles back in randomized controlled trial (ABrCt: braces versus neuromuscular exercises for the secondary prevention of ankle sprains. Design of a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Verhagen Evert ALM

    2011-09-01

    Full Text Available Abstract Background Ankle sprains are the most common sports and physical activity related injury. There is extensive evidence that there is a twofold increased risk for injury recurrence for at least one year post injury. In up to 50% of all cases recurrences result in disability and lead to chronic pain or instability, requiring prolonged medical care. Therefore ankle sprain recurrence prevention in athletes is essential. This RCT evaluates the effect of the combined use of braces and neuromuscular training (e.g. proprioceptive training/sensorimotor training/balance training against the individual use of either braces or neuromuscular training alone on ankle sprain recurrences, when applied to individual athletes after usual care. Methods/Design This study was designed as three way randomized controlled trial with one year follow-up. Healthy individuals between 12 and 70 years of age, who were actively participating in sports and who had sustained a lateral ankle sprain in the two months prior to inclusion, were eligible for inclusion. After subjects had finished ankle sprain treatment by means of usual care, they were randomised to any of the three study groups. Subjects in group 1 received an eight week neuromuscular training program, subjects in group 2 received a sports brace to be worn during all sports activities for the duration of one year, and group 3 received a combination of the neuromuscular training program and a sports brace to be worn during all sports activities for the duration of eight weeks. Outcomes were assessed at baseline and every month for 12 months therafter. The primary outcome measure was incidence of ankle sprain recurrences. Secondary outcome measures included the direct and indirect costs of recurrent injury, the severity of recurrent injury, and the residual complaints during and after the intervention. Discussion The ABrCt is the first randomized controlled trial to directly compare the secondary preventive

  10. Altered knee joint neuromuscular control during landing from a jump in 10-15year old children with Generalised Joint Hypermobility. A substudy of the CHAMPS-study Denmark

    DEFF Research Database (Denmark)

    Junge, Tina; Wedderkopp, Niels; Thorlund, Jonas Bloch

    2015-01-01

    Generalised Joint Hypermobility (GJH) is considered an intrinsic risk factor for knee injuries. Knee neuromuscular control during landing may be altered in GJH due to reduced passive stability. The aim was to identify differences in knee neuromuscular control during landing of the Single-Leg-Hop-...

  11. Consistency of Field-Based Measures of Neuromuscular Control Using Force-Plate Diagnostics in Elite Male Youth Soccer Players.

    Science.gov (United States)

    Read, Paul J; Oliver, Jon L; Croix, Mark Ba De Ste; Myer, Gregory D; Lloyd, Rhodri S

    2016-12-01

    Read, P, Oliver, JL, Croix, MD, Myer, GD, and Lloyd, RS. Consistency of field-based measures of neuromuscular control using force-plate diagnostics in elite male youth soccer players. J Strength Cond Res 30(12): 3304-3311, 2016-Deficits in neuromuscular control during movement patterns such as landing are suggested pathomechanics that underlie sport-related injury. A common mode of assessment is measurement of landing forces during jumping tasks; however, these measures have been used less frequently in male youth soccer players, and reliability data are sparse. The aim of this study was to examine the reliability of a field-based neuromuscular control screening battery using force-plate diagnostics in this cohort. Twenty-six pre-peak height velocity (PHV) and 25 post-PHV elite male youth soccer players completed a drop vertical jump (DVJ), single-leg 75% horizontal hop and stick (75%HOP), and single-leg countermovement jump (SLCMJ). Measures of peak landing vertical ground reaction force (pVGRF), time to stabilization, time to pVGRF, and pVGRF asymmetry were recorded. A test-retest design was used, and reliability statistics included change in mean, intraclass correlation coefficient, and coefficient of variation (CV). No significant differences in mean score were reported for any of the assessed variables between test sessions. In both groups, pVGRF and asymmetry during the 75%HOP and SLCMJ demonstrated largely acceptable reliability (CV ≤ 10%). Greater variability was evident in DVJ pVGRF and all other assessed variables, across the 3 protocols (CV range = 13.8-49.7%). Intraclass correlation coefficient values ranged from small to large and were generally higher in the post-PHV players. The results of this study suggest that pVGRF and asymmetry can be reliably assessed using a 75%HOP and SLCMJ in this cohort. These measures could be used to support a screening battery for elite male youth soccer players and for test-retest comparison.

  12. Short-term effects of neuromuscular blockade on global and regional lung mechanics, oxygenation and ventilation in pediatric acute hypoxemic respiratory failure

    OpenAIRE

    Wilsterman, Marlon E. F.; de Jager, Pauline; Blokpoel, Robert; Frerichs, Inez; Dijkstra, Sandra K.; Albers, Marcel J. I. J.; Burgerhof, Johannes G.M.; Markhorst, Dick G; Kneyber, Martin C. J.

    2016-01-01

    Background Neuromuscular blockade (NMB) has been shown to improve outcome in acute respiratory distress syndrome (ARDS) in adults, challenging maintaining spontaneous breathing when there is severe lung injury. We tested in a prospective physiological study the hypothesis that continuous administration of NMB agents in mechanically ventilated children with severe acute hypoxemic respiratory failure (AHRF) improves the oxygenation index without a redistribution of tidal volume V T toward non-d...

  13. THE RELAXOMETER - A COMPLETE AND COMPREHENSIVE COMPUTER-CONTROLLED NEUROMUSCULAR-TRANSMISSION MEASUREMENT SYSTEM DEVELOPED FOR CLINICAL RESEARCH ON MUSCLE-RELAXANTS

    NARCIS (Netherlands)

    ROWAAN, CJ; VANDENBROM, RHG; WIERDA, JMKH

    1993-01-01

    The Relaxometer is a computer-controlled system developed for reliable clinical experimental measurements on neuromuscular block. This system is based on an adapted personal computer (Atari 1040 ST) with a monochrome monitor (Atari SM 124), and a microcomputer-driven slave unit (stimulator). There a

  14. Nonholonomic mechanics and control

    CERN Document Server

    Murray, RM

    2015-01-01

    This book explores some of the connections between control theory and geometric mechanics; that is, control theory is linked with a geometric view of classical mechanics in both its Lagrangian and Hamiltonian formulations and in particular with the theory of mechanical systems subject to motion constraints. The synthesis of the topic is appropriate as there is a particularly rich connection between mechanics and nonlinear control theory. The book provides a unified treatment of nonlinear control theory and constrained mechanical systems and illustrates the elegant mathematics behind many simple, interesting, and useful mechanical examples. It is intended for graduate students who wish to learn this subject and researchers in the area who want to enhance their techniques. The book contains sections focusing on physical examples and elementary terms, as well as theoretical sections that use sophisticated analysis and geometry. The first four chapters offer preliminaries and background information, while the...

  15. The effects of neuromuscular training on knee joint motor control during sidecutting in female elite soccer and handball players

    DEFF Research Database (Denmark)

    Zebis, Mette K; Bencke, Jesper; Andersen, Lars

    2008-01-01

    and knee, and ground reaction forces were recorded during a sidecutting maneuver. Neuromuscular activity in the prelanding phase was obtained 10 and 50 ms before foot strike on a force plate and at 10 and 50 ms after foot strike on a force plate. RESULTS: Neuromuscular training markedly increased before...

  16. Using rolling to develop neuromuscular control and coordination of the core and extremities of athletes.

    Science.gov (United States)

    Hoogenboom, Barbara J; Voight, Michael L; Cook, Gray; Gill, Lance

    2009-05-01

    Rolling is a movement pattern seldom used by physical therapists for assessment and intervention with adult clientele with normal neurologic function. Rolling, as an adult motor skill, combines the use of the upper extremities, core, and lower extremities in a coordinated manner to move from one posture to another. Rolling is accomplished from prone to supine and supine to prone, although the method by which it is performed varies among adults. Assessment of rolling for both the ability to complete the task and bilateral symmetry may be beneficial for use with athletes who perform rotationally-biased sports such as golf, throwing, tennis, and twisting sports such as dance, gymnastics, and figure skating. Additionally, when used as intervention techniques, the rolling patterns have the ability to affect dysfunction of the upper quarter, core, and lower quarter. By applying proprioceptive neuromuscular facilitation (PNF) principles, the therapist may assist patients and clients who are unable to complete a rolling pattern. Examples given in the article include distraction/elongation, compression, and manual contacts to facilitate proper rolling. The combined experience of the four authors is used to describe techniques for testing, assessment, and treatment of dysfunction, using case examples that incorporate rolling. The authors assert that therapeutic use of the developmental pattern of rolling with techniques derived from PNF is a hallmark in rehabilitation of patients with neurologic dysfunction, but can be creatively and effectively utilized in musculoskeletal rehabilitation.

  17. Effects of plyometric and pneumatic explosive strength training on neuromuscular function and dynamic balance control in 60-70year old males.

    Science.gov (United States)

    Piirainen, Jarmo M; Cronin, Neil J; Avela, Janne; Linnamo, Vesa

    2014-04-01

    The present study compared neuromuscular adaptations to 12weeks of plyometric (PLY) or pneumatic (PNE) power training and their effects on dynamic balance control. Twenty-two older adults aged 60-70 (PLY n=9, PNE n=11) participated in the study. Measurements were conducted at Pre, 4, 8 and 12weeks. Dynamic balance was assessed as anterior-posterior center of pressure (COP) displacement in response to sudden perturbations. Explosive isometric knee extension and plantar flexion maximal voluntary contractions (MVCs) were performed. Maximal drop jump performance from optimal dropping height was measured in a sledge ergometer. Increases in knee extensor and ankle plantar flexor torque and muscle activity were higher and occurred sooner in PNE, whereas in drop jumping, PLY showed a clearer increase in optimal drop height (24%, ptraining and soleus muscle activity after 12weeks of training. In spite of these training mode specific adaptations, both groups showed similar improvements in dynamic balance control after 4weeks of training (PLY 38%, ptraining may involve different neural adaptation mechanisms, both training modes can produce similar improvements in dynamic balance control in older individuals. As COP displacement was negatively correlated with rapid knee extension torque in both groups (PLY r=-0.775, ptraining, the results also highlight the importance of targeting rapid force production when training older adults to improve dynamic balance.

  18. Effects of home-based resistance training and neuromuscular electrical stimulation in knee osteoarthritis: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Bruce-Brand Robert A

    2012-07-01

    Full Text Available Abstract Background Quadriceps femoris muscle (QFM weakness is a feature of knee osteoarthritis (OA and exercise programs that strengthen this muscle group can improve function, disability and pain. Traditional supervised resistance exercise is however resource intensive and dependent on good adherence which can be challenging to achieve in patients with significant knee OA. Because of the limitations of traditional exercise programs, interest has been shown in the use of neuromuscular electrical stimulation (NMES to strengthen the QFM. We conducted a single-blind, prospective randomized controlled study to compare the effects of home-based resistance training (RT and NMES on patients with moderate to severe knee OA. Methods 41 patients aged 55 to 75 years were randomised to 6 week programs of RT, NMES or a control group receiving standard care. The primary outcome was functional capacity measured using a walk test, stair climb test and chair rise test. Additional outcomes were self-reported disability, quadriceps strength and cross-sectional area. Outcomes were assessed pre- and post-intervention and at 6 weeks post-intervention (weeks 1, 8 and 14 respectively. Results There were similar, significant improvements in functional capacity for the RT and NMES groups at week 8 compared to week 1 (p≤0.001 and compared to the control group (p  Conclusions Home-based NMES is an acceptable alternative to exercise therapy in the management of knee OA, producing similar improvements in functional capacity. Trial registration: Current Controlled Trials ISRCTN85231954

  19. Center of mass acceleration feedback control of standing balance by functional neuromuscular stimulation against external postural perturbations.

    Science.gov (United States)

    Nataraj, Raviraj; Audu, Musa L; Triolo, Ronald J

    2013-01-01

    This study investigated the use of center of mass (COM) acceleration feedback for improving performance of a functional neuromuscular stimulation control system to restore standing function to a subject with complete, thoracic-level spinal cord injury. The approach for linearly relating changes in muscle stimulation to changes in COM acceleration was verified experimentally and subsequently produced data to create an input-output map driven by sensor feedback. The feedback gains were systematically tuned to reduce upper extremity (UE) loads applied to an instrumented support device while resisting external postural disturbances. Total body COM acceleration was accurately estimated (>89% variance explained) using 3-D outputs of two accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, feedback control of stimulation reduced UE loading by 33%. COM acceleration feedback is advantageous in constructing a standing neuroprosthesis since it provides the basis for a comprehensive control synergy about a global, dynamic variable and requires minimal instrumentation. Future work should include tuning and testing the feedback control system during functional reaching activity that is more indicative of activities of daily living.

  20. Knee joint biomechanics and neuromuscular control during gait before and after total knee arthroplasty are sex-specific.

    Science.gov (United States)

    Astephen Wilson, Janie L; Dunbar, Michael J; Hubley-Kozey, Cheryl L

    2015-01-01

    The future of total knee arthroplasty (TKA) surgery will involve planning that incorporates more patient-specific characteristics. Despite known biological, morphological, and functional differences between men and women, there has been little investigation into knee joint biomechanical and neuromuscular differences between men and women with osteoarthritis, and none that have examined sex-specific biomechanical and neuromuscular responses to TKA surgery. The objective of this study was to examine sex-associated differences in knee kinematics, kinetics and neuromuscular patterns during gait before and after TKA. Fifty-two patients with end-stage knee OA (28 women, 24 men) underwent gait and neuromuscular analysis within the week prior to and one year after surgery. A number of sex-specific differences were identified which suggest a different manifestation of end-stage knee OA between the sexes.

  1. Influência da procainamida sobre o bloqueio neuromuscular produzido pelo rocurônio e investigação sobre o mecanismo de ação da procainamida na junção neuromuscular Influencia de la procainamida sobre el bloqueo neuromuscular producido por el rocuronio e investigación sobre el mecanismo de acción de la procainamida en la junción neuromuscular Influence of procainamide on the neuromuscular blockade caused by rocuronium and investigation on the mechanism of action of procainamide on the neuromuscular junction

    Directory of Open Access Journals (Sweden)

    Thalita Duque Martins

    2007-02-01

    : It has already been proved that procainamide potentiates the neuromuscular blockade of d-tubocurarine; however, the mechanism of this potentiation is controversial. The aim of this study was to assess the influence of procainamide on the neuromuscular blockade produced by rocuronium and investigate the mechanisms of this interaction. METHODS: Fifteen rats (250 to 300 g were used in the preparation described by Bülbring. They were divided in three groups (n = 5 each: procainamide - 20 µg.mL-1 (Group I; rocuronium - 4 µg.mL-1 (Group II; and rocuronium - 4 µg.mL-1 and procainamide - 20 µg.mL-1 (Group III. The following parameters were evaluated: 1 amplitude of muscle contractions under indirect stimulation, before and after the administration of the drugs; 2 miniature end plate potentials (MEPPs; and 3 the efficacy of 4-aminopyridine in reverting the muscular blockade. The mechanism of the interaction was studied in Biventer cervicis (n = 5 and in the denervated rat diaphragm (n = 5, observing the influence of procainamide in the response to acetylcholine. RESULTS: Procainamide alone did not change the neuromuscular responses. Group III presented a 68.6% ± 7.1% blockade, which represented a statistically significant difference (p = 0.0067 when compared with Group II (10.4% ± 4.5%, which was reverted by 4-aminopiridine. Procainamide increased the frequency of the MEPP, followed by a blockade that was reverted by 4-aminopiridine. In Biventer cervicis, procainamide increased the contraction in response to acetylcholine, which was not observed in the denervated diaphragm. CONCLUSIONS: Procainamide potentiated the blockade caused by rocuronium. The changes observed with MEPP and Biventer cervicis identified pre-synaptic action. The antagonism of 4-aminopiridine on the blockade of the MEPP suggested receptor desensitization by procainamide.

  2. Neuromuscular control of scapula muscles during a voluntary task in subjects with Subacromial Impingement Syndrome. A case-control study.

    Science.gov (United States)

    Larsen, C M; Søgaard, K; Chreiteh, S S; Holtermann, A; Juul-Kristensen, B

    2013-10-01

    Imbalance of neuromuscular activity in the scapula stabilizers in subjects with Subacromial Impingement Syndrome (SIS) is described in restricted tasks and specific populations. Our aim was to compare the scapular muscle activity during a voluntary movement task in a general population with and without SIS (n=16, No-SIS=15). Surface electromyography was measured from Serratus anterior (SA) and Trapezius during bilateral arm elevation (no-load, 1kg, 3kg). Mean relative muscle activity was calculated for SA and the upper (UT) and lower part of trapezius (LWT), in addition to activation ratio and time to activity onset. In spite of a tendency to higher activity among SIS 0.10-0.30 between-group differences were not significant neither in ratio of muscle activation 0.80-0.98 nor time to activity onset 0.53-0.98. The hypothesized between-group differences in neuromuscular activity of Trapezius and Serratus was not confirmed. The tendency to a higher relative muscle activity in SIS could be due to a pain-related increase in co-activation or a decrease in maximal activation. The negative findings may display the variation in the specific muscle activation patterns depending on the criteria used to define the population of impingement patients, as well as the methodological procedure being used, and the shoulder movement investigated.

  3. Changes in Balance Strategy and Neuromuscular Control during a Fatiguing Balance Task—A Study in Perturbed Unilateral Stance

    Science.gov (United States)

    Ritzmann, Ramona; Freyler, Kathrin; Werkhausen, Amelie; Gollhofer, Albert

    2016-01-01

    Fatigue impairs sensorimotor performance, reduces spinal reflexes and affects the interaction of antagonistic muscles in complex motor tasks. Although there is literature dealing with the interference of fatigue and postural control, the interpretation is confounded by the variety of paradigms used to study it. This study aimed to evaluate the effects of postural fatigue on balance control and strategy, as well as on neuromuscular modulation, in response to postural perturbation (PERT) during a fatiguing balance task. A fatigue protocol consisting of continuous exposure to perturbations until exhaustion was executed in 24 subjects. Number of failed attempts, paths of center of pressure displacement (COP), ankle, knee, and hip joint kinematics, electromyographic activity of the soleus (SOL), tibialis anterior (TA), rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), and gluteus maximus muscles (GM) and spinal excitability of SOL at the peak of the short-latency responses (SLR) were recorded after posterior PERT. The co-contraction index (CCI) was calculated for TA_SOL, VL_BF and RF_GM. (1) The number of failed attempts significantly increased while COP amplitude and velocity, as well as angular excursion at the ankle, knee and hip joints, decreased with fatigue (P PERT. The reduction in spinal excitability may either be caused by fatigue itself or by an increase in reciprocal inhibition due to augmented TA activity. PMID:27378886

  4. The effects of neuromuscular exercise on medial knee joint load post-arthroscopic partial medial meniscectomy: ‘SCOPEX’ a randomised control trial protocol

    Directory of Open Access Journals (Sweden)

    Hall Michelle

    2012-11-01

    Full Text Available Abstract Background Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have recently undergone a partial medial meniscectomy. Methods/design 62 people aged 30–50 years who have undergone an arthroscopic partial medial meniscectomy within the previous 3 to 12 months will be recruited and randomly assigned to a neuromuscular exercise or control group using concealed allocation. The neuromuscular exercise group will attend 8 supervised exercise sessions with a physiotherapist and will perform 6 exercises at home, at least 3 times per week for 12 weeks. The control group will not receive the neuromuscular training program. Blinded assessment will be performed at baseline and immediately following the 12-week intervention. The primary outcomes are change in the peak external knee adduction moment measured by 3-dimensional analysis during normal paced walking and one-leg rise. Secondary outcomes include the change in peak external knee adduction moment during fast pace walking and one-leg hop and change in the knee adduction moment impulse during walking, one-leg rise and one-leg hop, knee and hip muscle strength, electromyographic muscle activation patterns, objective measures of physical function, as well as self-reported measures of physical function and symptoms and additional biomechanical parameters. Discussion The findings from this trial will provide evidence regarding the effect of a home

  5. Effect of upper extremity proprioceptive neuromuscular facilitation combined with elastic resistance bands on respiratory muscle strength: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Guilherme P. T. Areas

    2013-12-01

    Full Text Available BACKGROUND: Elastic resistance bands (ERB combined with proprioceptive neuromuscular facilitation (PNF are often used in resistance muscle training programs, which have potential effects on peripheral muscle strength. However, the effects of the combination of ERB and PNF on respiratory muscle strength warrant further investigation. OBJECTIVES: The assessment of the effects of PNF combined with ERB on respiratory muscle strength. METHOD: Twenty healthy, right-handed females were included. Subjects were randomized to either the resistance training program group (TG, n=10 or the control group (CG, n=10. Maximal expiratory pressure (MEP and inspiratory pressure (MIP were measured before and after four weeks of an upper extremity resistance training program. The training protocol consisted of upper extremity PNF combined with ERB, with resistance selected from 1 repetition maximum protocol. RESULTS: PNF combined with ERB showed significant increases in MIP and MEP (p<0.05. In addition, there were significant differences between the TG and CG regarding ∆MIP (p=0.01 and ∆MEP (p=0.04. CONCLUSIONS: PNF combined with ERB can have a positive impact on respiratory muscle strength. These results may be useful with respect to cardiopulmonary chronic diseases that are associated with reduced respiratory muscle strength.

  6. Sites and mechanisms of antibiotic-induced neuromuscular block: a pharmacological analysis using quantal content, voltage clamped end-plate currents and single channel analysis.

    Science.gov (United States)

    Fiekers, J F

    1999-01-01

    Since the original observation of Vital Brazil and Corrado (1957) concerning the antibiotic induced neuromuscular block produced by streptomycin, there has been considerable interest in the mechanisms responsible for not only neuromuscular block but also the effects of antibiotics on different systems. We used the voltage clamped end-plate of transacted skeletal muscle to examine the concentration-dependent actions of several groups of antibiotics. The aminoglycoside antibiotics, neomycin and streptomycin, were both more effective at reducing quantal release of acetylcholine (ACh) than interacting with the postjunctional ACh receptor-channel complex. Neomycin was approximately 10 X more potent prejunctionally than streptomycin and the prejunctional effects of each antibiotic were reversed competitively by raising extracellular calcium. Both neomycin and streptomycin also had postjunctional actions at higher concentrations. Neomycin interacted with the open state of the ACh receptor ion channel complex while streptomycin blocks the ACh receptor. The lincosamide antibiotics, lincomycin and clindamycin produced their neuromuscular block postjunctionally by interacting with the open state of the ACh-receptor channel complex. Clindamycin is approximately 20 X more effective at blocking the open channel than was lincomycin. Using cell attached patch clamp recordings in cultured rat myotubes, we demonstrated a lincosamide-induced block of open ion channels with clindamycin having a much slower unblocking rate than lincomycin. Using epimers of the lincosamides, we demonstrated that lipophilicity of the molecule, rather than stereochemical considerations, is important for open channel blockade affecting primarily the "off" rate of channel blocking. This mechanism appears important for not only the lincosamide antibiotics but also for the postjunctional actions of the aminoglycoside antibiotics, particularly neomycin.

  7. Proximal versus distal control of two-joint planar reaching movements in the presence of neuromuscular noise.

    Science.gov (United States)

    Nguyen, Hung P; Dingwell, Jonathan B

    2012-06-01

    Determining how the human nervous system contends with neuro-motor noise is vital to understanding how humans achieve accurate goal-directed movements. Experimentally, people learning skilled tasks tend to reduce variability in distal joint movements more than in proximal joint movements. This suggests that they might be imposing greater control over distal joints than proximal joints. However, the reasons for this remain unclear, largely because it is not experimentally possible to directly manipulate either the noise or the control at each joint independently. Therefore, this study used a 2 degree-of-freedom torque driven arm model to determine how different combinations of noise and/or control independently applied at each joint affected the reaching accuracy and the total work required to make the movement. Signal-dependent noise was simultaneously and independently added to the shoulder and elbow torques to induce endpoint errors during planar reaching. Feedback control was then applied, independently and jointly, at each joint to reduce endpoint error due to the added neuromuscular noise. Movement direction and the inertia distribution along the arm were varied to quantify how these biomechanical variations affected the system performance. Endpoint error and total net work were computed as dependent measures. When each joint was independently subjected to noise in the absence of control, endpoint errors were more sensitive to distal (elbow) noise than to proximal (shoulder) noise for nearly all combinations of reaching direction and inertia ratio. The effects of distal noise on endpoint errors were more pronounced when inertia was distributed more toward the forearm. In contrast, the total net work decreased as mass was shifted to the upper arm for reaching movements in all directions. When noise was present at both joints and joint control was implemented, controlling the distal joint alone reduced endpoint errors more than controlling the proximal joint

  8. Speed adaptation in a powered transtibial prosthesis controlled with a neuromuscular model

    OpenAIRE

    Markowitz, Jared; Krishnaswamy, Pavitra; Eilenberg, Michael F.; ENDO, Ken; Barnhart, Chris; Herr, Hugh

    2011-01-01

    Control schemes for powered ankle–foot prostheses would benefit greatly from a means to make them inherently adaptive to different walking speeds. Towards this goal, one may attempt to emulate the intact human ankle, as it is capable of seamless adaptation. Human locomotion is governed by the interplay among legged dynamics, morphology and neural control including spinal reflexes. It has been suggested that reflexes contribute to the changes in ankle joint dynamics that correspond to walking ...

  9. Effects of Tai Chi versus Proprioception Exercise Program on Neuromuscular Function of the Ankle in Elderly People: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Jing Liu

    2012-01-01

    Full Text Available Background. Tai Chi is a traditional Chinese medicine exercise used for improving neuromuscular function. This study aimed to investigate the effects of Tai Chi versus proprioception exercise program on neuromuscular function of the ankle in elderly people. Methods. Sixty elderly subjects were randomly allocated into three groups of 20 subjects per group. For 16 consecutive weeks, subjects participated in Tai Chi, proprioception exercise, or no structured exercise. Primary outcome measures included joint position sense and muscle strength of ankle. Subjects completed a satisfaction questionnaire upon study completion in Tai Chi and proprioception groups. Results. (1 Both Tai Chi group and proprioception exercise group were significantly better than control group in joint position sense of ankle, and there were no significant differences in joint position sense of ankle between TC group and PE group. (2 There were no significant differences in muscle strength of ankle among groups. (3 Subjects expressed more satisfaction with Tai Chi than with proprioception exercise program. Conclusions. None of the outcome measures on neuromuscular function at the ankle showed significant change posttraining in the two structured exercise groups. However, the subjects expressed more interest in and satisfaction with Tai Chi than proprioception exercise.

  10. Effects of shared medical appointments on quality of life and cost-effectiveness for patients with a chronic neuromuscular disease. Study protocol of a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    van der Wilt Gert-Jan

    2011-08-01

    Full Text Available Abstract Background Shared medical appointments are a series of one-to-one doctor-patient contacts, in presence of a group of 6-10 fellow patients. This group visits substitute the annual control visits of patients with the neurologist. The same items attended to in a one-to- one appointment are addressed. The possible advantages of a shared medical appointment could be an added value to the present management of neuromuscular patients. The currently problem-focused one-to-one out-patient visits often leave little time for the patient's psychosocial needs, patient education, and patient empowerment. Methods/design A randomized, prospective controlled study (RCT with a follow up of 6 months will be conducted to evaluate the clinical and cost-effectiveness of shared medical appointments compared to usual care for 300 neuromuscular patients and their partners at the Radboud University Nijmegen Medical Center. Every included patient will be randomly allocated to one of the two study arms. This study has been reviewed and approved by the medical ethics committee of the region Arnhem-Nijmegen, the Netherlands. The primary outcome measure is quality of life as measured by the EQ-5D, SF-36 and the Individualized neuromuscular Quality of Life Questionnaire. The primary analysis will be an intention-to-treat analysis on the area under the curve of the quality of life scores. A linear mixed model will be used with random factor group and fixed factors treatment, baseline score and type of neuromuscular disease. For the economic evaluation an incremental cost-effectiveness analysis will be conducted from a societal perspective, relating differences in costs to difference in health outcome. Results are expected in 2012. Discussion This study will be the first randomized controlled trial which evaluates the effect of shared medical appointments versus usual care for neuromuscular patients. This will enable to determine if there is additional value of shared

  11. Functional Neuromuscular Stimulation Controlled by Surface Electromyographic Signals Produced by Volitional Activation of the Same Muscle

    DEFF Research Database (Denmark)

    Sennels, Søren; Biering-Sørensen, Fin; Andersen, Ole Trier

    1997-01-01

    In order to use the volitional electromyography (EMG) as a control signal for the stimulation of the same muscle, it is necessary to eliminate the stimulation artifacts and the muscle responses caused by the stimulation. The stimulation artifacts, caused by the electric field in skin and tissue...... generated by the stimulation current, are relatively easy to eliminate by shutting down the EMG-amplifier at the onset of the stimulation pulses. The muscle response is a nonstationary signal, therefore, an adaptive linear prediction filter is proposed. The filter is implemented and for three filter lengths...... the shut-down circuit and the adaptive filter both the stimulation artifacts and the muscle responses can be effectively eliminated from the EMG signal from a stimulated muscle. It is therefore possible to extract the volitional EMG from a partly paralyzed muscle and use it for controlling the stimulation...

  12. Training for improved neuro-muscular control of balance in middle aged females.

    Science.gov (United States)

    Anderson, Gregory S; Deluigi, Fabio; Belli, Guido; Tentoni, Claudio; Gaetz, Michael B

    2016-01-01

    This study examined improvements in static balance and muscle electromyographic (EMG) activity following a four week progressive training program in 16 middle aged females (mean age = 46.9 ± 8.7 yrs; height 161.1 ± 6.0 cm; weight 65.4 ± 11.2 kg). Participants trained 3 times per week for 4 weeks, for 50 min per session, progressing base of support, stability, vision, resistance and torque in each of six basic exercises. Pre and post training measures of balance included feet together standing, a tandem stance and a one-leg stand (unsupported leg in the saggital plane) performed with the eyes closed, and a Stork Stand (unsupported leg in the frontal plane) with both eyes open and closed. In each position postural deviations were tallied for each individual while muscle recruitment was determined using root mean squared (RMS) EMG activity for the soleus, biceps femoris, erector spinae, rectus abdominis and internal oblique muscles of the dominant foot side. Balance scores were significantly improved post training in both the Balance Error Score System (p core stability allowed participants to move from a hip to an ankle postural control strategy through improved coordination of muscles involved in balance and reduced body sway. The core muscles were able to control body position with less activity post training suggesting improved muscle coordination and efficiency. These results suggest that short term progressive floor to BOSU™ balance training can improve standing balance in middle aged women.

  13. Characteristics of Neuromuscular Control of the Scapula after Stroke: A First Exploration

    Science.gov (United States)

    De Baets, Liesbet; Jaspers, Ellen; Janssens, Luc; Van Deun, Sara

    2014-01-01

    This study aimed to characterize scapular muscle timing in stroke patients with and without shoulder pain. Muscle activity of upper trapezius, lower trapezius, serratus anterior, infraspinatus, and anterior deltoid (AD) was measured (Delsys Trigno surface EMG system, USA) in 14 healthy controls (dominant side) and 30 stroke patients (hemiplegic side) of whom 10 had impingement-like shoulder pain. Participants performed 45° and full range anteflexion, in two load conditions. The impact of group, anteflexion height, load condition, and muscle was assessed for onset and offset of the different muscles relative to the onset and offset of AD, using a 3 (group) × 2 (height) × 2 (load) × 4 (muscle) mixed model design. Recruitment patterns were additionally described. Across all load conditions and groups, serratus anterior had a significantly earlier onset and, together with lower trapezius, a significantly later offset in 45° compared to full range anteflexion tasks (p < 0.001). In stroke patients without pain, lower trapezius had furthermore a significantly earlier onset in comparison to stroke patients with shoulder pain (all tasks, p = 0.04). Serratus anterior also showed a significantly earlier offset in stroke patients with shoulder pain in comparison to controls (p = 0.01) and stroke patients without pain (p < 0.001). Analysis of muscle recruitment patterns indicated that for full range tasks, stroke patients without pain used early and prolonged activity of infraspinatus. In stroke patients with shoulder pain, recruitment patterns were characterized by delayed activation and early inactivity of serratus anterior. These timing results can serve as a reference frame for scapular muscle timing post-stroke, and when designing upper limb treatment protocols and clinical guidelines for shoulder pain after stroke. PMID:25477805

  14. Comparison of neuromuscular and quadriceps strengthening exercise in the treatment of varus malaligned knees with medial knee osteoarthritis: a randomised controlled trial protocol

    Directory of Open Access Journals (Sweden)

    Bennell Kim L

    2011-12-01

    Full Text Available Abstract Background Osteoarthritis of the knee involving predominantly the medial tibiofemoral compartment is common in older people, giving rise to pain and loss of function. Many people experience progressive worsening of the disease over time, particularly those with varus malalignment and increased medial knee joint load. Therefore, interventions that can reduce excessive medial knee loading may be beneficial in reducing the risk of structural progression. Traditional quadriceps strengthening can improve pain and function in people with knee osteoarthritis but does not appear to reduce medial knee load. A neuromuscular exercise program, emphasising optimal alignment of the trunk and lower limb joints relative to one another, as well as quality of movement performance, while dynamically and functionally strengthening the lower limb muscles, may be able to reduce medial knee load. Such a program may also be superior to traditional quadriceps strengthening with respect to improved pain and physical function because of the functional and dynamic nature. This randomised controlled trial will investigate the effect of a neuromuscular exercise program on medial knee joint loading, pain and function in individuals with medial knee joint osteoarthritis. We hypothesise that the neuromuscular program will reduce medial knee load as well as pain and functional limitations to a greater extent than a traditional quadriceps strengthening program. Methods/Design 100 people with medial knee pain, radiographic medial compartment osteoarthritis and varus malalignment will be recruited and randomly allocated to one of two 12-week exercise programs: quadriceps strengthening or neuromuscular exercise. Each program will involve 14 supervised exercise sessions with a physiotherapist plus four unsupervised sessions per week at home. The primary outcomes are medial knee load during walking (the peak external knee adduction moment from 3D gait analysis, pain, and self

  15. The Effects of Plyometric Type Neuromuscular Training on Postural Control Performance of Male Team Basketball Players.

    Science.gov (United States)

    Asadi, Abbas; Saez de Villarreal, Eduardo; Arazi, Hamid

    2015-07-01

    Anterior cruciate ligament injuries are common in basketball athletes; common preventive programs for decreasing these injures may be enhancing postural control (PC) or balance with plyometric training. This study investigated the efficiency of plyometric training program within basketball practice to improve PC performance in young basketball players. Sixteen players were recruited and assigned either to a plyometric + basketball training group (PT) or basketball training group (BT). All players trained twice per week, but the PT + BT followed a 6-week plyometric program implemented within basketball practice, whereas the BT followed regular practice. The star excursion balance test (SEBT) at 8 directions (anterior, A; anteromedial, AM; anterolateral, AL; medial, M; lateral, L; posterior, P; posteromedial, PM; and posterolateral, PL) was measured before and after the 6-week period. The PT group induced significant improvement (p ≤ 0.05) and small to moderate effect size in the SEBT (A = 0.95, AM = 0.62, AL = 0.61, M = 0.36, L = 0.47, P = 0.27, PM = 0.25, PL = 0.24). No significant improvements were found in the BT group. Also, there were significant differences between groups in all directions except PM and PL. An integrated plyometric program within the regular basketball practice can lead to significant improvements in SEBT and consequently PC. It can be recommended that strength and conditioning professionals use PT to enhance the athletes' joint awareness and PC to reduce possible future injuries in the lower extremity.

  16. Modelagem e simulação do sistema neuromuscular responsável pelo controle do torque gerado na articulação do tornozelo.

    OpenAIRE

    Leonardo Abdala Elias

    2013-01-01

    O estudo do controle neurofisiológico do movimento tem sido realizado sob várias perspectivas. Experimentos com seres humanos são realizados durante a execução de uma dada tarefa motora e, frequentemente, mediante a aplicação de estímulos externos (elétrico, magnético ou mecânico) ao sistema neuromuscular. Estes experimentos fornecem uma grande quantidade de dados referentes ao funcionamento das redes neuronais e dos atuadores biomecânicos envolvidos nos procedimentos. Entretanto, alguns acha...

  17. The effects of neuromuscular exercise on medial knee joint load post-arthroscopic partial medial meniscectomy: 'SCOPEX', a randomised control trial protocol

    DEFF Research Database (Denmark)

    Hall, Michelle; Hinman, Rana S; Wrigley, Tim V

    2012-01-01

    Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential...... to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have...

  18. Doenças neuromusculares Neuromuscular disorders

    OpenAIRE

    Umbertina C. Reed

    2002-01-01

    Objetivo: apresentar os dados essenciais para o diagnóstico diferencial entre as principais doenças neuromusculares, denominação genérica sob a qual agrupam-se diferentes afecções, decorrentes do acometimento primário da unidade motora (motoneurônio medular, raiz nervosa, nervo periférico, junção mioneural e músculo). Fontes dos dados: os aspectos clínicos fundamentais para estabelecer o diagnóstico diferencial entre as diferentes doenças neuromusculares, bem como entre estas e as causas de h...

  19. Feedback Control of arm movements using Neuro-Muscular Electrical Stimulation (NMES combined with a lockable, passive exoskeleton for gravity compensation

    Directory of Open Access Journals (Sweden)

    Christian eKlauer

    2014-09-01

    Full Text Available Within the European project MUNDUS, an assistive framework was developed for the support of arm and hand functions during daily life activities in severely impaired people. Potential users of this system are patients with high-level spinal cord injury and neurodegenerative neuromuscular diseases, such as amyotrophic lateral sclerosis, Friedreich ataxia, and multiple sclerosis. This contribution aims at designing a feedback control system for Neuro-Muscular Electrical Stimulation (NMES to enable reaching functions in people with no residual voluntary control of the arm due to upper motor neuron lesions after spinal cord injury. NMES is applied to the deltoids and the biceps muscles and integrated with a three degrees of freedom (DoFs passive exoskeleton, which partially compensates gravitational forces and allows to lock each DOF. The user is able to choose the target hand position and to trigger actions using an eyetracker system. The target position is selected by using the eyetracker and determined by a marker-based tracking system using Microsoft Kinect. A central controller, i.e. a finite state machine, issues a sequence of basic movement commands to the real-time arm controller. The NMES control algorithm sequentially controls each joint angle while locking the other DoFs. Daily activities, such as drinking, brushing hair, pushing an alarm button, etc., can be supported by the system. The robust and easily tunable control approach was evaluated with five healthy subjects during a drinking task. Subjects were asked to remain passive and to allow NMES to induce the movements. In all of them, the controller was able to perform the task, and a mean hand positioning error of less than five centimeters was achieved. The average total time duration for moving the hand from a rest position to a drinking cup, for moving the cup to the mouth and back, and for finally returning the arm to the rest position was 71 seconds.

  20. Neuromuscular disorders in pregnancy.

    Science.gov (United States)

    Guidon, Amanda C; Massey, E Wayne

    2012-08-01

    Preexisting and coincident neuromuscular disorders in pregnancy are challenging for clinicians because of the heterogeneity of disease and the limited data in the literature. Many questions arise regarding the effect of disease on the pregnancy, delivery, and newborn in addition to the effect of pregnancy on the course of disease. Each disorder has particular considerations and possible complications. An interdisciplinary team of physicians is essential. This article discusses the most recent literature on neuromuscular disorders in pregnancy including acquired root, plexus, and peripheral nerve lesions; acquired and inherited neuropathies and myopathies; disorders of the neuromuscular junction; and motor neuron diseases.

  1. Using the Hephaistos orthotic device to study countermeasure effectiveness of neuromuscular electrical stimulation and dietary lupin protein supplementation, a randomised controlled trial

    Science.gov (United States)

    Schopen, Kathrin; Albracht, Kirsten; Gerlach, Darius A.; Frings-Meuthen, Petra; Maffiuletti, Nicola A.; Bloch, Wilhelm; Rittweger, Jörn

    2017-01-01

    Purpose The present study investigated whether neuromuscular electrical stimulation for 20 min twice a day with an electrode placed over the soleus muscle and nutritional supplementation with 19 g of protein rich lupin seeds can reduce the loss in volume and strength of the human calf musculature during long term unloading by wearing an orthotic unloading device. Methods Thirteen healthy male subjects (age of 26.4 ± 3.7 years) wore a Hephaistos orthosis one leg for 60 days during all habitual activities. The leg side was randomly chosen for every subject. Six subjects only wore the orthosis as control group, and 7 subjects additionally received the countermeasure consisting of neuromuscular electrical stimulation of the soleus and lateral gastrocnemius muscles and lupin protein supplementation. Twenty-eight days before and on the penultimate day of the intervention cross-sectional images of the calf muscles were taken by magnetic resonance imaging (controls n = 5), and maximum voluntary torque (controls n = 6) of foot plantar flexion was estimated under isometric (extended knee, 90° knee flexion) and isokinetic conditions (extended knee), respectively. Results After 58 days of wearing the orthosis the percentage loss of volume in the entire triceps surae muscle of the control subjects (-11.9 ± 4.4%, mean ± standard deviation) was reduced by the countermeasure (-3.5 ± 7.2%, p = 0.032). Wearing the orthosis generally reduced plantar flexion torques values, however, only when testing isometric contraction at 90° knee ankle the countermeasure effected a significantly lower percentage decrease of torque (-9.7 ± 7.2%, mean ± SD) in comparison with controls (-22.3 ± 11.2%, p = 0.032). Conclusion Unloading of calf musculature by an orthotic device resulted in the expected loss of muscle volume and maximum of plantar flexion torque. Neuromuscular electrical muscle stimulation and lupin protein supplementation could significantly reduce the process of atrophy. Trial

  2. Doenças neuromusculares Neuromuscular disorders

    Directory of Open Access Journals (Sweden)

    Umbertina C. Reed

    2002-08-01

    Full Text Available Objetivo: apresentar os dados essenciais para o diagnóstico diferencial entre as principais doenças neuromusculares, denominação genérica sob a qual agrupam-se diferentes afecções, decorrentes do acometimento primário da unidade motora (motoneurônio medular, raiz nervosa, nervo periférico, junção mioneural e músculo. Fontes dos dados: os aspectos clínicos fundamentais para estabelecer o diagnóstico diferencial entre as diferentes doenças neuromusculares, bem como entre estas e as causas de hipotonia muscular secundária ao comprometimento do sistema nervoso central ou a doenças sistêmicas não-neurológicas, são enfatizados, com base na experiência clínica vinda do atendimento a crianças com doenças neuromusculares durante os últimos 12 anos, no ambulatório de doenças neuromusculares do Hospital das Clínicas da Faculdade de Medicina, da Universidade de São Paulo. A revisão bibliográfica foi efetuada através do Medline e do periódico Neuromuscular Disorders, publicação oficial da World Muscle Society. Síntese dos dados: nas crianças, a maior parte destas afecções é geneticamente determinada, sendo as mais comuns a distrofia muscular progressiva ligada ao sexo, de Duchenne, a amiotrofia espinal infantil, a distrofia muscular congênita, a distrofia miotônica de Steinert, e as miopatias congênitas, estruturais e não estruturais. Polineuropatias hereditárias, síndrome miastênica congênita e miopatias metabólicas são menos comuns, porém mostram correlação geno-fenotípica cada vez mais precisa. Conclusões: na década passada, inúmeros avanços da genética molecular facilitaram imensamente o diagnóstico e o aconselhamento genético das doenças neuromusculares mais comuns das crianças, inclusive possibilitando diagnóstico fetal e, adicionalmente, vieram permitir melhor caracterização fenotípica e classificação mais objetiva.Objective: to discuss the most important aspects for performing a

  3. Steroidal neuromuscular blocking agents

    NARCIS (Netherlands)

    Wierda, JMKH; Mori, K; Ohmura, A; Toyooka, H; Hatano, Y; Shingu, K; Fukuda, K

    1998-01-01

    Since 1964 approximately 20 steroidal neuromuscular blocking agents have been evaluated clinically. Pancuronium, a bisquaternary compound designed on the drawingboard, was the first steroidal relaxant introduced into clinical practice worldwide in the 1970's. Although a major improvement, pancuroniu

  4. Controlled mechanized trepan.

    Science.gov (United States)

    Kam, J; Goldratt, E M; Barishak, Y R; Stein, R

    1978-04-01

    A mechanized trepan is described whose cutting action is halted automatically when the trepan's cutting edge reaches the last 0.03 mm. tissue layer of the cornea. The automatic half of both the motor which advances the trepan as well as the second motor which rotates the trepan is triggered by the sudden change in electrical resistance between the trepan and the patient's internal body fluid, at the final stage of penetration. This automatic feature eliminates the danger of inadvertant damage to the inner structures of the eye.

  5. Efeitos da estimulação elétrica neuromuscular durante a imobilização nas propriedades mecânicas do músculo esquelético Efectos de la estimulación eléctrica neuromuscular durante la inmovilización en las propiedades mecánicas del músculo esquelético Effects of neuromuscular electric stimulation during immobilization in the mechanical properties of the skeletal muscle

    Directory of Open Access Journals (Sweden)

    João Paulo Chieregato Matheus

    2007-02-01

    inmovilizadas en alongamiento y electro estimuladas (ILP + EE. Para la inmovilización, el miembro posterior derecho fue envuelto por una malla tubular y vendas de algodón en conjunto con vendas de escayola. La EENM fue utilizada con una frecuencia de 50 Hz, 10 minutos por día, totalizando 20 contracciones en cada sesión. Después de 7 días los animales fueron sometidos a eutanasia y los músculos gastrocnemios fueron retirados para la realización del ensayo mecánico de tracción en una máquina universal de ensayos (EMIC®. A partir de los gráficos carga versus alongamiento se calculó las siguientes propiedades mecánicas: alongamiento en el límite de proporcionalidad (ALP, carga en el límite de proporcionalidad (CLP y rigidez. Las inmovilizaciones SP y LP dieron reducciones significativas (p The neuromuscular electric stimulation (NMES is an important tool used in sports medicine to accelerate the recovery process. The objective of this study was to analyze the effects of NMES during immobilization of the gastrocnemius muscle, in lengthened (LP and shortened positions (SP. Sixty young female Wistar rats were distributed into six groups and followed for 7 days: control (C; electric stimulation (ES; immobilized in shortening (ISP; immobilized in lengthening (ILP; immobilized in shortening and electric stimulation (ISP + ES and immobilized in lengthening and electric stimulation (ILP + ES. For the immobilization, a tubular mesh and cotton rolls together with the plaster were wrapped around the rat's right posterior paw. NMES in a frequency of 50 Hz was used 10 minutes a day, totaling 20 contractions in each session. After 7 days the animals were sacrificed and their gastrocnemius muscles of the right paw were submitted to a mechanical test of traction in a universal test machine (EMIC®. From the load versus elongation curves the following mechanical properties were obtained: elongation in the yield limit (EPL, load in the yield limit (LPL and stiffness. The SP and LP

  6. Bouncing on Mars and the Moon-the role of gravity on neuromuscular control: correlation of muscle activity and rate of force development.

    Science.gov (United States)

    Ritzmann, Ramona; Freyler, Kathrin; Krause, Anne; Gollhofer, Albert

    2016-11-01

    On our astronomical neighbors Mars and the Moon, bouncing movements are the preferred locomotor techniques. During bouncing, the stretch-shortening cycle describes the muscular activation pattern. This study aimed to identify gravity-dependent changes in kinematic and neuromuscular characteristics in the stretch-shortening cycle. Hence, neuromuscular control of limb muscles as well as correlations between the muscles' pre-activation, reflex components, and force output were assessed in lunar, Martian, and Earth gravity. During parabolic flights, peak force (Fmax), ground-contact-time, rate of force development (RFD), height, and impulse were measured. Electromyographic (EMG) activities in the m. soleus (SOL) and gastrocnemius medialis (GM) were assessed before (PRE) and during bounces for the reflex phases short-, medium-, and long-latency response (SLR, MLR, LLR). With gradually decreasing gravitation, Fmax, RFD, and impulse were reduced, whereas ground-contact time and height increased. Concomitantly, EMG_GM decreased for PRE, SLR, MLR, and LLR, and in EMG_SOL in SLR, MLR, and LLR. For SLR and MLR, Fmax and RFD were positively correlated to EMG_SOL. For PRE and LLR, RFD and Fmax were positively correlated to EMG_GM. Findings emphasize that biomechanically relevant kinematic adaptations in response to gravity variation were accompanied by muscle- and phase-specific modulations in neural control. Gravitational variation is anticipated and compensated for by gravity-adjusted muscle activities. Importantly, the pre-activation and reflex phases were differently affected: in SLR and MLR, SOL is assumed to contribute to the decline in force output with a decreasing load, and, complementary in PRE and LLR, GM seems to be of major importance for force generation.

  7. Scoliosis and the impact in neuromuscular disease.

    Science.gov (United States)

    Mayer, Oscar Henry

    2015-01-01

    Scoliosis can alter respiratory mechanics by changing the orientation of the muscles and joints of the respiratory system and in severe forms can put a patient at risk of severe respiratory morbidity or respiratory failure. However, perhaps the most important factor in determining the pulmonary morbidity in scoliosis is the balance between the "load" or altered respiratory mechanics and the "pump" or the respiratory muscle strength. Therefore, scoliosis in patients with neuromuscular disease will both lead to increased "load" and a weakened "pump", an exceptionally unfortunate combination. While progressive neuromuscular disease by its nature does not respond favorably to attempts to improve respiratory muscle strength, the natural approach of early proactive management of the "load" and in the case of scoliosis a variety of different strategies have been tried with variable short term and long term results. Figuring this out requires both an understanding of the underlying pathophysiology of a particular neuromuscular condition and the available options for and timing of surgical intervention.

  8. Optimal Control of Mechanical Systems

    OpenAIRE

    Vadim Azhmyakov

    2007-01-01

    In the present work, we consider a class of nonlinear optimal control problems, which can be called “optimal control problems in mechanics.” We deal with control systems whose dynamics can be described by a system of Euler-Lagrange or Hamilton equations. Using the variational structure of the solution of the corresponding boundary-value problems, we reduce the initial optimal control problem to an auxiliary problem of multiobjective programming. This technique makes it possible to apply some ...

  9. The Effect of Plyometric Training on Trunk Muscle Pre-activation in Active Females with Trunk Neuromuscular Control Deficit

    Directory of Open Access Journals (Sweden)

    M Hadadnezhad

    2014-02-01

    Results: the results of independent sample T-test indicated that there are significant differences between post-test of control and experimental groups in regard to Gluteus Medius (p=0.021, Quadratus Lumborum (p=0.011, Transverse Abdominis/Internal oblique (p=0.006, External Oblique (p=0.023 muscles activations which reveals effectiveness of plyometric training on pre-activation of muscles. Conclusion: Based on the study results, plyometric training affects the activation of muscles and thus improving the pre-activation can prevent mechanisms related to anterior cruciate ligament injury. Therefore, plyometric training can reduce incidence of anterior cruciate ligament injury.

  10. Hereditary neuromuscular diseases

    Energy Technology Data Exchange (ETDEWEB)

    Oezsarlak, O. E-mail: ozkan.ozsarlak@uza.be; Schepens, E.; Parizel, P.M.; Goethem, J.W. van; Vanhoenacker, F.; Schepper, A.M. de; Martin, J.J

    2001-12-01

    This article presents the actual classification of neuromuscular diseases based on present expansion of our knowledge and understanding due to genetic developments. It summarizes the genetic and clinical presentations of each disorder together with CT findings, which we studied in a large group of patients with neuromuscular diseases. The muscular dystrophies as the largest and most common group of hereditary muscle diseases will be highlighted by giving detailed information about the role of CT and MRI in the differential diagnosis. The radiological features of neuromuscular diseases are atrophy, hypertrophy, pseudohypertrophy and fatty infiltration of muscles on a selective basis. Although the patterns and distribution of involvement are characteristic in some of the diseases, the definition of the type of disease based on CT scan only is not always possible.

  11. Optimal Control of Mechanical Systems

    Directory of Open Access Journals (Sweden)

    Vadim Azhmyakov

    2007-01-01

    Full Text Available In the present work, we consider a class of nonlinear optimal control problems, which can be called “optimal control problems in mechanics.” We deal with control systems whose dynamics can be described by a system of Euler-Lagrange or Hamilton equations. Using the variational structure of the solution of the corresponding boundary-value problems, we reduce the initial optimal control problem to an auxiliary problem of multiobjective programming. This technique makes it possible to apply some consistent numerical approximations of a multiobjective optimization problem to the initial optimal control problem. For solving the auxiliary problem, we propose an implementable numerical algorithm.

  12. Electrodiagnosis in neuromuscular disease.

    Science.gov (United States)

    Lipa, Bethany M; Han, Jay J

    2012-08-01

    Electromyography (EMG) is an important diagnostic tool for the assessment of individuals with various neuromuscular diseases. It should be an extension of a thorough history and physical examination. Some prototypical characteristics and findings of EMG and nerve conduction studies are discussed; however, a more thorough discussion can be found in the textbooks and resources sited in the article. With an increase in molecular genetic diagnostics, EMG continues to play an important role in the diagnosis and management of patients with neuromuscular diseases and also provides a cost-effective diagnostic workup before ordering a battery of costly genetic tests.

  13. PROGNOSTIC VALUE OF INITIAL ASSESSMENT OF RESIDUAL HYPOVENTILATION USING NOCTURNAL CAPNOGRAPHY IN MECHANICALLY VENTILATED NEUROMUSCULAR PATIENTS: A 5 YEARS FOLLOW-UP STUDY.

    Directory of Open Access Journals (Sweden)

    Adam Ogna

    2016-09-01

    Full Text Available BackgroundRestrictive respiratory failure is a major cause of morbidity and mortality in neuromuscular diseases (NMD. Home mechanical ventilation (HMV is used to treat hypoventilation, and its efficiency is mostly assessed by daytime blood gases or nocturnal oxygen saturation monitoring (SpO2. Non-invasive transcutaneous measure of CO2 (TcCO2 allows to directly assess nocturnal hypercapnia and to detect residual hypoventilation with a higher sensitivity than SpO2.We aimed to compare the prognostic value of nocturnal SpO2 and TcCO2 in ventilated adult NMD patients. MethodsAll consecutive capno-oximetries performed between 2010 and 2011 in ventilated adult NMD patients were analysed retrospectively. Concomitant blood gas analysis and lung function data were collected. Patients on oxygen therapy were excluded. Nocturnal hypoxemia and hypercapnia (using 4 different definitions at baseline were compared in their ability to predict mortality and respiratory events requiring ICU admission during follow-up. ResultsData from 55 patients were analysed (median age 28 IQR 25 - 36.5 years; 71% Duchenne muscular dystrophy; vital capacity 12 7 - 27 % of predicted; 51% tracheostomy.Capno-oxymetry showed hypoxemia in 14.5% and hypercapnia in 12.7 to 41.8%, according to the used definition.Over a follow-up lasting up to 5 years (median 4.0 3.6 - 4.5 years, we observed 12 deaths and 20 respiratory events requiring ICU admission. Hypercapnia was significantly associated with the study outcomes, with TcCO2 >49 mmHg during ≥10% of the time being the best definition, whilst hypoxemia was not.ConclusionsOur data show for the first time that residual hypoventilation, assessed by capnometry, is significantly associated with negative outcomes in adult ventilated NMD patients, whilst oximetry is not. Accordingly, we suggest capnometry to be included in the systematic assessment of HMV efficiency in NMD patients.

  14. Active zone stability: insights from fly neuromuscular junction

    Directory of Open Access Journals (Sweden)

    Xiaolin Tian

    2015-01-01

    Full Text Available The presynaptic active zone is a dynamic structure that orchestrates regulated release of neurotransmitters. Developmental and aging processes, and changes in neuronal network activity can all modulate the number, size and composition of active zone and thereby synaptic efficacy. However, very little is known about the mechanism that controls the structural stability of active zone. By studying a model synapse, the Drosophila neuromuscular junction, our recent work shed light on how two scaffolding proteins at the active zone regulate active zone stability by promoting a localized dephosphorylation event at the nerve terminal. Here we discuss the major insights from our findings and their implications for future research.

  15. Feedback control of arm movements using Neuro-Muscular Electrical Stimulation (NMES) combined with a lockable, passive exoskeleton for gravity compensation.

    Science.gov (United States)

    Klauer, Christian; Schauer, Thomas; Reichenfelser, Werner; Karner, Jakob; Zwicker, Sven; Gandolla, Marta; Ambrosini, Emilia; Ferrante, Simona; Hack, Marco; Jedlitschka, Andreas; Duschau-Wicke, Alexander; Gföhler, Margit; Pedrocchi, Alessandra

    2014-01-01

    Within the European project MUNDUS, an assistive framework was developed for the support of arm and hand functions during daily life activities in severely impaired people. This contribution aims at designing a feedback control system for Neuro-Muscular Electrical Stimulation (NMES) to enable reaching functions in people with no residual voluntary control of the arm and shoulder due to high level spinal cord injury. NMES is applied to the deltoids and the biceps muscles and integrated with a three degrees of freedom (DoFs) passive exoskeleton, which partially compensates gravitational forces and allows to lock each DOF. The user is able to choose the target hand position and to trigger actions using an eyetracker system. The target position is selected by using the eyetracker and determined by a marker-based tracking system using Microsoft Kinect. A central controller, i.e., a finite state machine, issues a sequence of basic movement commands to the real-time arm controller. The NMES control algorithm sequentially controls each joint angle while locking the other DoFs. Daily activities, such as drinking, brushing hair, pushing an alarm button, etc., can be supported by the system. The robust and easily tunable control approach was evaluated with five healthy subjects during a drinking task. Subjects were asked to remain passive and to allow NMES to induce the movements. In all of them, the controller was able to perform the task, and a mean hand positioning error of less than five centimeters was achieved. The average total time duration for moving the hand from a rest position to a drinking cup, for moving the cup to the mouth and back, and for finally returning the arm to the rest position was 71 s.

  16. Effect of a 6-week dynamic neuromuscular training programme on ankle joint function: A Case report

    LENUS (Irish Health Repository)

    O'Driscoll, Jeremiah

    2011-06-09

    Abstract Background Ankle joint sprain and the subsequent development of chronic ankle instability (CAI) are commonly encountered by clinicians involved in the treatment and rehabilitation of musculoskeletal injuries. It has recently been advocated that ankle joint post-sprain rehabilitation protocols should incorporate dynamic neuromuscular training to enhance ankle joint sensorimotor capabilities. To date no studies have reported on the effects of dynamic neuromuscular training on ankle joint positioning during landing from a jump, which has been reported as one of the primary injury mechanisms for ankle joint sprain. This case report details the effects of a 6-week dynamic neuromuscular training programme on ankle joint function in an athlete with CAI. Methods The athlete took part in a progressive 6-week dynamic neuromuscular training programme which incorporated postural stability, strengthening, plyometric, and speed\\/agility drills. The outcome measures chosen to assess for interventional efficacy were: 1 Cumberland Ankle Instability Tool (CAIT) scores, 2 Star Excursion Balance Test (SEBT) reach distances, 3 ankle joint plantar flexion during drop landing and drop vertical jumping, and 4 ground reaction forces (GRFs) during walking. Results CAIT and SEBT scores improved following participation in the programme. The angle of ankle joint plantar flexion decreased at the point of initial contact during the drop landing and drop vertical jumping tasks, indicating that the ankle joint was in a less vulnerable position upon landing following participation in the programme. Furthermore, GRFs were reduced whilst walking post-intervention. Conclusions The 6-week dynamic neuromuscular training programme improved parameters of ankle joint sensorimotor control in an athlete with CAI. Further research is now required in a larger cohort of subjects to determine the effects of neuromuscular training on ankle joint injury risk factors.

  17. Effect of a 6-week dynamic neuromuscular training programme on ankle joint function: A Case report

    Directory of Open Access Journals (Sweden)

    O'Driscoll Jeremiah

    2011-06-01

    Full Text Available Abstract Background Ankle joint sprain and the subsequent development of chronic ankle instability (CAI are commonly encountered by clinicians involved in the treatment and rehabilitation of musculoskeletal injuries. It has recently been advocated that ankle joint post-sprain rehabilitation protocols should incorporate dynamic neuromuscular training to enhance ankle joint sensorimotor capabilities. To date no studies have reported on the effects of dynamic neuromuscular training on ankle joint positioning during landing from a jump, which has been reported as one of the primary injury mechanisms for ankle joint sprain. This case report details the effects of a 6-week dynamic neuromuscular training programme on ankle joint function in an athlete with CAI. Methods The athlete took part in a progressive 6-week dynamic neuromuscular training programme which incorporated postural stability, strengthening, plyometric, and speed/agility drills. The outcome measures chosen to assess for interventional efficacy were: 1 Cumberland Ankle Instability Tool (CAIT scores, 2 Star Excursion Balance Test (SEBT reach distances, 3 ankle joint plantar flexion during drop landing and drop vertical jumping, and 4 ground reaction forces (GRFs during walking. Results CAIT and SEBT scores improved following participation in the programme. The angle of ankle joint plantar flexion decreased at the point of initial contact during the drop landing and drop vertical jumping tasks, indicating that the ankle joint was in a less vulnerable position upon landing following participation in the programme. Furthermore, GRFs were reduced whilst walking post-intervention. Conclusions The 6-week dynamic neuromuscular training programme improved parameters of ankle joint sensorimotor control in an athlete with CAI. Further research is now required in a larger cohort of subjects to determine the effects of neuromuscular training on ankle joint injury risk factors.

  18. Electrodiagnosis of disorders of neuromuscular transmission.

    Science.gov (United States)

    Howard, James F

    2013-02-01

    This article reviews the use of electrodiagnostic testing in disorders of neuromuscular transmission and discusses the differences between various presynaptic and postsynaptic disorders. Attention is paid to quality control issues that influence the sensitivity of repetitive nerve stimulation and single fiber electromyography. Electrodiagnostic testing, when used as an extension of the clinician's history and physical examination, will provide appropriate direction in establishing the diagnosis.

  19. Cellular mechanisms that control mistranslation

    DEFF Research Database (Denmark)

    Reynolds, Noah M; Lazazzera, Beth A; Ibba, Michael

    2010-01-01

    Mistranslation broadly encompasses the introduction of errors during any step of protein synthesis, leading to the incorporation of an amino acid that is different from the one encoded by the gene. Recent research has vastly enhanced our understanding of the mechanisms that control mistranslation...

  20. Mitochondrial dysfunction in neuromuscular disorders.

    Science.gov (United States)

    Katsetos, Christos D; Koutzaki, Sirma; Melvin, Joseph J

    2013-09-01

    This review deciphers aspects of mitochondrial (mt) dysfunction among nosologically, pathologically, and genetically diverse diseases of the skeletal muscle, lower motor neuron, and peripheral nerve, which fall outside the traditional realm of mt cytopathies. Special emphasis is given to well-characterized mt abnormalities in collagen VI myopathies (Ullrich congenital muscular dystrophy and Bethlem myopathy), megaconial congenital muscular dystrophy, limb-girdle muscular dystrophy type 2 (calpainopathy), centronuclear myopathies, core myopathies, inflammatory myopathies, spinal muscular atrophy, Charcot-Marie-Tooth neuropathy type 2, and drug-induced peripheral neuropathies. Among inflammatory myopathies, mt abnormalities are more prominent in inclusion body myositis and a subset of polymyositis with mt pathology, both of which are refractory to corticosteroid treatment. Awareness is raised about instances of phenotypic mimicry between cases harboring primary mtDNA depletion, in the context of mtDNA depletion syndrome, and established neuromuscular disorders such as spinal muscular atrophy. A substantial body of experimental work, derived from animal models, attests to a major role of mitochondria (mt) in the early process of muscle degeneration. Common mechanisms of mt-related cell injury include dysregulation of the mt permeability transition pore opening and defective autophagy. The therapeutic use of mt permeability transition pore modifiers holds promise in various neuromuscular disorders, including muscular dystrophies.

  1. Chaos Control in Mechanical Systems

    Directory of Open Access Journals (Sweden)

    Marcelo A. Savi

    2006-01-01

    Full Text Available Chaos has an intrinsically richness related to its structure and, because of that, there are benefits for a natural system of adopting chaotic regimes with their wide range of potential behaviors. Under this condition, the system may quickly react to some new situation, changing conditions and their response. Therefore, chaos and many regulatory mechanisms control the dynamics of living systems, conferring a great flexibility to the system. Inspired by nature, the idea that chaotic behavior may be controlled by small perturbations of some physical parameter is making this kind of behavior to be desirable in different applications. Mechanical systems constitute a class of system where it is possible to exploit these ideas. Chaos control usually involves two steps. In the first, unstable periodic orbits (UPOs that are embedded in the chaotic set are identified. After that, a control technique is employed in order to stabilize a desirable orbit. This contribution employs the close-return method to identify UPOs and a semi-continuous control method, which is built up on the OGY method, to stabilize some desirable UPO. As an application to a mechanical system, a nonlinear pendulum is considered and, based on parameters obtained from an experimental setup, analyses are carried out. Signals are generated by numerical integration of the mathematical model and two different situations are treated. Firstly, it is assumed that all state variables are available. After that, the analysis is done from scalar time series and therefore, it is important to evaluate the effect of state space reconstruction. Delay coordinates method and extended state observers are employed with this aim. Results show situations where these techniques may be used to control chaos in mechanical systems.

  2. Comparison of mechanomyography and acceleromyography for the assessment of rocuronium induced neuromuscular block in myotonic dystrophy type 1.

    NARCIS (Netherlands)

    Vanlinthout, L.E.H.; Booij, L.H.D.J.; Egmond, J. van; Robertson, E.N.

    2010-01-01

    We measured acceleromyography and mechanomyography simultaneously with monitoring of rocuronium-induced neuromuscular block in four patients with myotonic dystrophy type 1. Furthermore, we compared neuromuscular block measures from these patients with those from normal controls from previous studies

  3. [Characteristics of neuromuscular scoliosis].

    Science.gov (United States)

    Putzier, M; Groß, C; Zahn, R K; Pumberger, M; Strube, P

    2016-06-01

    Usually, neuromuscular scolioses become clinically symptomatic relatively early and are rapidly progressive even after the end of growth. Without sufficient treatment they lead to a severe reduction of quality of life, to a loss of the ability of walking, standing or sitting as well as to an impairment of the cardiopulmonary system resulting in an increased mortality. Therefore, an intensive interdisciplinary treatment by physio- and ergotherapists, internists, pediatricians, orthotists, and orthopedists is indispensable. In contrast to idiopathic scoliosis the treatment of patients with neuromuscular scoliosis with orthosis is controversially discussed, whereas physiotherapy is established and essential to prevent contractures and to maintain the residual sensorimotor function.Frequently, the surgical treatment of the scoliosis is indicated. It should be noted that only long-segment posterior correction and fusion of the whole deformity leads to a significant improvement of the quality of life as well as to a prevention of a progression of the scoliosis and the development of junctional problems. The surgical intervention is usually performed before the end of growth. A prolonged delay of surgical intervention does not result in an increased height but only in a deformity progression and is therefore not justifiable. In early onset neuromuscular scolioses guided-growth implants are used to guarantee the adequat development. Because of the high complication rates, further optimization of these implant systems with regard to efficiency and safety have to be addressed in future research.

  4. The role of proprioception and neuromuscular stability in carpal instabilities.

    Science.gov (United States)

    Hagert, E; Lluch, A; Rein, S

    2016-01-01

    Carpal stability has traditionally been defined as dependent on the articular congruity of joint surfaces, the static stability maintained by intact ligaments, and the dynamic stability caused by muscle contractions resulting in a compression of joint surfaces. In the past decade, a fourth factor in carpal stability has been proposed, involving the neuromuscular and proprioceptive control of joints. The proprioception of the wrist originates from afferent signals elicited by sensory end organs (mechanoreceptors) in ligaments and joint capsules that elicit spinal reflexes for immediate joint stability, as well as higher order neuromuscular influx to the cerebellum and sensorimotor cortices for planning and executing joint control. The aim of this review is to provide an understanding of the role of proprioception and neuromuscular control in carpal instabilities by delineating the sensory innervation and the neuromuscular control of the carpus, as well as descriptions of clinical applications of proprioception in carpal instabilities.

  5. Assessment of neuromuscular fatigue by frequency analysis of the electromyographic signal of the control subjects and patients suffering from temporomandibular disorders treated with occlusal splints resilient and rigid

    OpenAIRE

    2012-01-01

    A incapacidade de produzir repetidamente no tempo um determinado nível de força ou potência muscular designa-se por fadiga neuromuscular. A etiologia da fadiga muscular tem atraído o interesse de pesquisadores há mais de um século. Contudo, os seus agentes e locais definitivos permanecem ainda por serem identificados. Este trabalho teve por objetivo avaliar a fadiga neuromuscular por meio da análise de frequência do sinal eletromiográfico dos músculos masseter e temporal anterior de ambos os ...

  6. Patterning mechanisms controlling digit development

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Vertebrate digits are essential structures for movement,feeding and communication.Specialized regions of the developing limb bud including the zone of polarizing activity(ZPA),the apical ectodermal ridge(AER),and the non-ridge ectoderm regulate the patterning of digits.Although a series of signaling molecules have been characterized as patterning signals from the organizing centers,the delicate cellular and molecular mechanisms that interpret how these patterning signals control the detailed digit anatomy remain unclear.Recent studies from model organisms and human hand malformations provide new insights into the mechanisms regulating this process.Here,we review the current understanding of the genetic networks governing digit morphogenesis.

  7. Autoregulatory mechanisms controlling the microprocessor.

    Science.gov (United States)

    Triboulet, Robinson; Gregory, Richard I

    2011-01-01

    The Microprocessor, comprising the ribonuclease Drosha and its essential cofactor, the double-stranded RNA-binding protein, DGCR8, is essential for the first step of the miRNA biogenesis pathway. It specifically cleaves double-stranded RNA within stem-loop structures of primary miRNA transcripts (pri-miRNAs) to generate precursor (pre-miRNA) intermediates. Pre-miRNAs are subsequently processed by Dicer to their mature ∼22 nt form. Thus, Microprocessor is essential for miRNA maturation, and pri-miRNA cleavage by this complex defines one end of the mature miRNA. Moreover, it is emerging that dysregulation of the Microprocessor is associated with various human diseases. It is therefore important to understand the mechanisms by which the expression of the subunits of the Microprocessor is regulated. Recent findings have uncovered a post-transcriptional mechanism that maintains the integrity of the Microprocessor. These studies revealed that the Microprocessor is involved in the processing of the messenger RNA (mRNA) that encodes DGCR8. This regulatory feedback loop, along with the reported role played by DGCR8 in the stabilization of Drosha protein, is part of a newly identified regulatory mechanism controlling Microprocessor activity.

  8. Plyometric type neuromuscular exercise is a treatment to postural control deficits of volleyball players: A case study

    Directory of Open Access Journals (Sweden)

    A. Asadi

    2016-06-01

    Conclusions: It can be recommend that strength and conditioning professionals in the field of volleyball do not perform other type of landing exercise in plyometric training sessions because of postural control impaired and consequently the probability of lower extremity injuries will increase.

  9. Control mechanisms for ecological-economic systems

    CERN Document Server

    Burkov, Vladimir N; Shchepkin, Alexander V

    2015-01-01

    This monograph presents and analyzes the optimization, game-theoretic and simulation models of control mechanisms for ecological-economic systems. It is devoted to integrated assessment mechanisms for total risks and losses, penalty mechanisms, risk payment mechanisms, financing and costs compensation mechanisms for risk level reduction, sales mechanisms for risk level quotas, audit mechanisms, mechanisms for expected losses reduction, economic motivation mechanisms, optimization mechanisms for regional environmental (risk level reduction) programs, and mechanisms for authorities' interests coordination. The book is aiming at undergraduate and postgraduate students, as well as at experts in mathematical modeling and control of ecological economic, socioeconomic and organizational systems.

  10. Neuromuscular control of a single twitch muscle in wild type and mutant Drosophila, measured with an ergometer.

    Science.gov (United States)

    Harvey, Jennifer; Brunger, Holly; Middleton, C Adam; Hill, Julia A; Sevdali, Maria; Sweeney, Sean T; Sparrow, John C; Elliott, Christopher J H

    2008-06-01

    How do deficits in neuronal growth, aging or synaptic function affect the final, mechanical output of a single muscle twitch? We address this in vivo (indeed in situ) with a novel ergometer that records the output of a large specialised muscle, the Drosophila jump muscle. Here, we describe in detail the ergometer, its construction and use. We evaluated the ergometer by showing that adult fly jump muscle output varies little between 3 h and 7 days; but newly eclosed flies produce only 65%. In a mutant with little octopamine (Tbetah), jump muscle performance is reduced by 28%. The initial responses of synaptic growth mutants (highwire and spinster) do not differ from wild type, as expected on the homeostatic hypothesis. However, responses in highwire mutations gradually decline following repeated stimuli, suggesting physiological as well as anatomical abnormalities. We conclude that the assay is robust, sensitive and reliable with a good throughput.

  11. Corticosteroids and neuromuscular blockers in development of critical illness neuromuscular abnormalities: A historical review.

    Science.gov (United States)

    Wilcox, Susan R

    2017-02-01

    Weakness is common in critically ill patients, associated with prolonged mechanical ventilation and increased mortality. Corticosteroids and neuromuscular blockade (NMB) administration have been implicated as etiologies of acquired weakness in the intensive care unit. Medical literature since the 1970s is replete with case reports and small case series of patients with weakness after receiving high-dose corticosteroids, prolonged NMB, or both. Several risk factors for weakness appear in the early literature, including large doses of steroids, the dose and duration of NMB, hyperglycemia, and the duration of mechanical ventilation. With improved quality of data, however, the association between weakness and steroids or NMB wanes. This may reflect changes in clinical practice, such as a reduction in steroid dosing, use of cisatracurium besylate instead of aminosteroid NMBs, improved glycemic control, or trends in minimizing mechanical ventilatory support. Thus, based on the most recent and high-quality literature, neither corticosteroids in commonly used doses nor NMB is associated with increased duration of mechanical ventilation, the greatest morbidity of weakness. Minimizing ventilator support as soon as the patient's condition allows may be associated with a reduction in weakness-related morbidity.

  12. Role of calcium and vesicle-docking proteins in remobilising dormant neuromuscular junctions in desert frogs.

    Science.gov (United States)

    Lavidis, Nickolas A; Hudson, Nicholas J; Choy, Peng T; Lehnert, Sigrid A; Franklin, Craig E

    2008-01-01

    Despite prolonged immobility the desert frog, Cyclorana alboguttata, suffers little impairment in muscle function. To determine compensatory mechanisms at neuromuscular junctions, transmitter release was examined along primary terminals in C. alboguttata iliofibularis muscle. Using extracellular recording we found the amplitudes of evoked endplate currents were significantly smaller in dormant frogs. In active frogs we identified two negatively sloping proximal-distal gradients of transmitter frequency and quantal content; a shallow proximal-distal gradient with low probability of transmitter release (0.6). During aestivation, only a shallow gradient was identified. The high probability release sites in control frogs were inhibited during aestivation by a mechanism that could be reversed by (1) increasing the extracellular calcium concentration, and (2) increasing the frequency of stimulation. This suggests that transmitter vesicles are available during aestivation but not released. We quantified expression of messenger RNA transcripts coding for the transmitter vesicle-docking proteins synaptotagmin 1, syntaxin 1B and UNC-13. All three were rare transcripts maintained at control values during aestivation. Neuromuscular remobilisation after dormancy in C. alboguttata is more likely a product of rapidly reversible physiologic mechanisms than reorganisations of the neuromuscular transcriptome.

  13. Functional Neuromuscular Stimulation Controlled by Surface Electromyographic Signals Produced by the Volitional Activation of the Same Muscle:

    DEFF Research Database (Denmark)

    Sennels, Søren; Fin, Biering-Sørensen; Andersen, Ole Trier

    1997-01-01

    Using the voluntary EMG as a control signal for the stimulation of the same muscle necessitates elimination of stimulus artifacts and the muscle response caused by the stimulation. The stimulus artifacts are easily eliminated by shutting down the amplifier during stimulation. The muscle response...... is a non-stationary signal, therefore an adaptive linear prediction filter is proposed. The filter is derived and tested for three filter lengths on both simulated and real data. The performance is compared with a conventional fixed comb filter. The simulations indicate that the adaptive filter...

  14. Respiratory motor training and neuromuscular plasticity in patients with chronic obstructive pulmonary disease: A pilot study.

    Science.gov (United States)

    Ovechkin, Alexander V; Sayenko, Dimitry G; Ovechkina, Elena N; Aslan, Sevda C; Pitts, Teresa; Folz, Rodney J

    2016-07-15

    The objective of this study was to examine the feasibility of a full-scale investigation of the neurophysiological mechanisms of COPD-induced respiratory neuromuscular control deficits. Characterization of respiratory single- and multi-muscle activation patterns using surface electromyography (sEMG) were assessed along with functional measures at baseline and following 21±2 (mean±SD) sessions of respiratory motor training (RMT) performed during a one-month period in four patients with GOLD stage II or III COPD. Pre-training, the individuals with COPD showed significantly increased (prespiratory muscle activity and disorganized multi-muscle activation patterns in association with lowered spirometrical measures and decreased fast- and slow-twitch fiber activity as compared to healthy controls (N=4). Following RMT, functional and respiratory sEMG activation outcomes during quite breathing and forced expiratory efforts were improved suggesting that functional improvements, induced by task-specific RMT, are evidence respiratory neuromuscular networks re-organization.

  15. An alpha-catulin homologue controls neuromuscular function through localization of the dystrophin complex and BK channels in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Linu S Abraham

    2010-08-01

    Full Text Available The large conductance, voltage- and calcium-dependent potassium (BK channel serves as a major negative feedback regulator of calcium-mediated physiological processes and has been implicated in muscle dysfunction and neurological disorders. In addition to membrane depolarization, activation of the BK channel requires a rise in cytosolic calcium. Localization of the BK channel near calcium channels is therefore critical for its function. In a genetic screen designed to isolate novel regulators of the Caenorhabditis elegans BK channel, SLO-1, we identified ctn-1, which encodes an α-catulin homologue with homology to the cytoskeletal proteins α-catenin and vinculin. ctn-1 Mutants resemble slo-1 loss-of-function mutants, as well as mutants with a compromised dystrophin complex. We determined that CTN-1 uses two distinct mechanisms to localize SLO-1 in muscles and neurons. In muscles, CTN-1 utilizes the dystrophin complex to localize SLO-1 channels near L-type calcium channels. In neurons, CTN-1 is involved in localizing SLO-1 to a specific domain independent of the dystrophin complex. Our results demonstrate that CTN-1 ensures the localization of SLO-1 within calcium nanodomains, thereby playing a crucial role in muscles and neurons.

  16. Neuromuscular Exercise Post Partial Medial Meniscectomy

    DEFF Research Database (Denmark)

    Hall, Michelle; Hinman, Rana S; Wrigley, Tim V;

    2015-01-01

    PURPOSE: To evaluate the effects of a 12-week, home-based, physiotherapist-guided neuromuscular exercise program on the knee adduction moment (an indicator of mediolateral knee load distribution) in people with a medial arthroscopic partial meniscectomy within the past 3-12 months. METHODS......: An assessor-blinded, randomised controlled trial including people aged 30-50 years with no to mild pain following medial arthroscopic partial meniscectomy was conducted. Participants were randomly allocated to either a 12-week neuromuscular exercise program that targeted neutral lower limb alignment...... or a control group with no exercise. The exercise program included eight individual sessions with one of seven physiotherapists in private clinics, together with home exercises. Primary outcomes were the peak external knee adduction moment during normal pace walking and during a one-leg sit-to-stand. Secondary...

  17. Neuromuscular complications of acromegaly.

    Science.gov (United States)

    Pickett, J B; Layzer, R B; Levin, S R; Scheider, V; Campbell, M J; Sumner, A J

    1975-07-01

    Seventeen consecutive acromegalic patients were evaluated for evidence of neuromuscular dysfunction and followed for 1 year after hypophysectomy. Before treatment, four patients had both a myopathy and the carpal tunnel syndrome, five had myopathy alone, four had carpal tunnel syndrome alone, and four had neither. The myopathy was caracterized by mild, strictly promixal weakness and flabbiness of muscles; electromyography revealed typical myopathic abnormalities, but serum enzymes and muscle biopsy usually were normal. The presence of myopathy or the carpal tunnel syndrrome could not be correlated with the magnitude of growth hormone elevation or any secondary endocrine derangement, but myopathy was associated with a longer duration of acromegaly. Carpal tunnel symptoms usually improved in the first 6 weeks after hypophysectomy, while myopathy improved more slowly and sometimes was detectable 1 year later.

  18. Effects of avoiding neuromuscular blocking agents during maintenance of anaesthesia on recovery characteristics in patients undergoing craniotomy for supratentorial lesions: A randomised controlled study

    Directory of Open Access Journals (Sweden)

    Ruchi A Jain

    2017-01-01

    Full Text Available Background and Aims: Neuromuscular blocking agents have been one of the cornerstones of anaesthesia. With the advent of newer surgical, anaesthetic and neurological monitoring techniques, their utility in neuroanaesthesia practice seems dispensable. The aim of this prospective, comparative, randomised study was to determine whether neuromuscular blocking agents are required in patients undergoing supratentorial surgery when balanced anaesthesia with desflurane, dexmedetomidine and scalp block is used. Methods: Sixty patients with the American Society of Anesthesiologists physical status I or II, aged between 18 and 60 years were included in the study. All patients received anaesthesia including desflurane, dexmedetomidine and scalp block. The patients were randomly allocated to receive no neuromuscular blocking agent (Group A or atracurium infusion to keep train-of-four count 2 (Group B. The two groups were compared with respect to haemodynamic stability, brain relaxation scores and recovery characteristics. Haemodynamic parameters and time taken to achieve Aldrete score >9 and other secondary outcomes were analysed using Student's t-test. Non-parametric data were analysed using the Mann–Whitney test. Results: The mean arterial pressure was comparable between the groups. The intraoperative heart rate was comparable; however, in the post-operative period, it remained higher in Group B for 30 min after extubation (P = 0.02. The brain relaxation scores were comparable among the two groups (P = 0.27. Tracheal extubation time, time taken for orientation and time required to reach Aldrete score ≥9 were comparable among the two groups. Conclusion: The present study suggests that balanced anaesthesia using desflurane, dexmedetomidine and scalp block can preclude the use of neuromuscular blocking agents in patients undergoing supratentorial surgery under intense haemodynamic monitoring.

  19. Neuromuscular adaptation to actual and simulated weightlessness

    Science.gov (United States)

    Edgerton, V. R.; Roy, R. R.

    1994-01-01

    The chronic "unloading" of the neuromuscular system during spaceflight has detrimental functional and morphological effects. Changes in the metabolic and mechanical properties of the musculature can be attributed largely to the loss of muscle protein and the alteration in the relative proportion of the proteins in skeletal muscle, particularly in the muscles that have an antigravity function under normal loading conditions. These adaptations could result in decrements in the performance of routine or specialized motor tasks, both of which may be critical for survival in an altered gravitational field, i.e., during spaceflight and during return to 1 G. For example, the loss in extensor muscle mass requires a higher percentage of recruitment of the motor pools for any specific motor task. Thus, a faster rate of fatigue will occur in the activated muscles. These consequences emphasize the importance of developing techniques for minimizing muscle loss during spaceflight, at least in preparation for the return to 1 G after spaceflight. New insights into the complexity and the interactive elements that contribute to the neuromuscular adaptations to space have been gained from studies of the role of exercise and/or growth factors as countermeasures of atrophy. The present chapter illustrates the inevitable interactive effects of neural and muscular systems in adapting to space. It also describes the considerable progress that has been made toward the goal of minimizing the functional impact of the stimuli that induce the neuromuscular adaptations to space.

  20. Mechanisms of TSC-mediated control of synapse assembly and axon guidance.

    Directory of Open Access Journals (Sweden)

    Sarah Knox

    Full Text Available Tuberous sclerosis complex is a dominant genetic disorder produced by mutations in either of two tumor suppressor genes, TSC1 and TSC2; it is characterized by hamartomatous tumors, and is associated with severe neurological and behavioral disturbances. Mutations in TSC1 or TSC2 deregulate a conserved growth control pathway that includes Ras homolog enriched in brain (Rheb and Target of Rapamycin (TOR. To understand the function of this pathway in neural development, we have examined the contributions of multiple components of this pathway in both neuromuscular junction assembly and photoreceptor axon guidance in Drosophila. Expression of Rheb in the motoneuron, but not the muscle of the larval neuromuscular junction produced synaptic overgrowth and enhanced synaptic function, while reductions in Rheb function compromised synapse development. Synapse growth produced by Rheb is insensitive to rapamycin, an inhibitor of Tor complex 1, and requires wishful thinking, a bone morphogenetic protein receptor critical for functional synapse expansion. In the visual system, loss of Tsc1 in the developing retina disrupted axon guidance independently of cellular growth. Inhibiting Tor complex 1 with rapamycin or eliminating the Tor complex 1 effector, S6 kinase (S6k, did not rescue axon guidance abnormalities of Tsc1 mosaics, while reductions in Tor function suppressed those phenotypes. These findings show that Tsc-mediated control of axon guidance and synapse assembly occurs via growth-independent signaling mechanisms, and suggest that Tor complex 2, a regulator of actin organization, is critical in these aspects of neuronal development.

  1. Effects of carbohydrates-BCAAs-caffeine ingestion on performance and neuromuscular function during a 2-h treadmill run: a randomized, double-blind, cross-over placebo-controlled study

    Directory of Open Access Journals (Sweden)

    Peltier Sébastien L

    2011-12-01

    Full Text Available Abstract Background Carbohydrates (CHOs, branched-chain amino acids (BCAAs and caffeine are known to improve running performance. However, no information is available on the effects of a combination of these ingredients on performance and neuromuscular function during running. Methods The present study was designed as a randomized double-blind cross-over placebo-controlled trial. Thirteen trained adult males completed two protocols, each including two conditions: placebo (PLA and Sports Drink (SPD: CHOs 68.6 g.L-1, BCAAs 4 g.L-1, caffeine 75 mg.L-1. Protocol 1 consisted of an all-out 2 h treadmill run. Total distance run and glycemia were measured. In protocol 2, subjects exercised for 2 h at 95% of their lowest average speeds recorded during protocol 1 (whatever the condition. Glycemia, blood lactate concentration and neuromuscular function were determined immediately before and after exercise. Oxygen consumption (V˙O2, heart rate (HR and rate of perceived exertion (RPE were recorded during the exercise. Total fluids ingested were 2 L whatever the protocols and conditions. Results Compared to PLA, ingestion of SPD increased running performance (p = 0.01, maintained glycemia and attenuated central fatigue (p = 0.04, an index of peripheral fatigue (p = 0.04 and RPE (p = 0.006. Maximal voluntary contraction, V˙O2, and HR did not differ between the two conditions. Conclusions This study showed that ingestion of a combination of CHOs, BCAAs and caffeine increased performance by about 2% during a 2-h treadmill run. The results of neuromuscular function were contrasted: no clear cut effects of SPD were observed. Trial registration ClinicalTrials.gov, http://www.clinicaltrials.gov, NCT00799630

  2. Neuromuscular disease classification system

    Science.gov (United States)

    Sáez, Aurora; Acha, Begoña; Montero-Sánchez, Adoración; Rivas, Eloy; Escudero, Luis M.; Serrano, Carmen

    2013-06-01

    Diagnosis of neuromuscular diseases is based on subjective visual assessment of biopsies from patients by the pathologist specialist. A system for objective analysis and classification of muscular dystrophies and neurogenic atrophies through muscle biopsy images of fluorescence microscopy is presented. The procedure starts with an accurate segmentation of the muscle fibers using mathematical morphology and a watershed transform. A feature extraction step is carried out in two parts: 24 features that pathologists take into account to diagnose the diseases and 58 structural features that the human eye cannot see, based on the assumption that the biopsy is considered as a graph, where the nodes are represented by each fiber, and two nodes are connected if two fibers are adjacent. A feature selection using sequential forward selection and sequential backward selection methods, a classification using a Fuzzy ARTMAP neural network, and a study of grading the severity are performed on these two sets of features. A database consisting of 91 images was used: 71 images for the training step and 20 as the test. A classification error of 0% was obtained. It is concluded that the addition of features undetectable by the human visual inspection improves the categorization of atrophic patterns.

  3. Active zone stability:insights from fly neuromuscular junction

    Institute of Scientific and Technical Information of China (English)

    Xiaolin Tian; Chunlai Wu

    2015-01-01

    The presynaptic active zone is a dynamic structure that orchestrates regulated release of neurotrans-mitters. Developmental and aging processes, and changes in neuronal network activity can all modulate the number, size and composition of active zone and thereby synaptic efifcacy. However, very little is known about the mechanism that controls the structural stability of active zone. By study-ing a model synapse, theDrosophila neuromuscular junction, our recent work shed light on how two scaffolding proteins at the active zone regulate active zone stability by promoting a localized dephos-phorylation event at the nerve terminal. Here we discuss the major insights from our ifndings and their implications for future research.

  4. Upper limb functions regained in quadriplegia: a hybrid computerized neuromuscular stimulation system.

    Science.gov (United States)

    Nathan, R H; Ohry, A

    1990-05-01

    A new, computerized neuromuscular stimulation system was applied to the upper limbs of two patients with complete quadriplegia below the C4 level. The stimulation-generated movements were integrated and augmented by residual, voluntary shoulder girdle movements and mechanical splinting. Up to 12 muscles were stimulated individually with high-resolution surface electrodes; coordination and control of the stimulation was effected by microcomputer. Simple vocal commands to the computer triggered preprogrammed hand prehensions, arm motion, and other functions, giving the patient complete control over the system. In pilot clinical trials of six weeks, writing, eating, and drinking, including picking up and replacing the pen or cup, were achieved.

  5. Neuromuscular activity and knee kinematics in adolescents with patellofemoral pain

    DEFF Research Database (Denmark)

    Rathleff, Michael Skovdal; Samani, Afshin; Olesen, Jens L.;

    2013-01-01

    This study aimed to investigate the neuromuscular control of the knee during stair descent among female adolescents with patellofemoral pain (PFP) and to report its association with self-reported clinical status assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS).......This study aimed to investigate the neuromuscular control of the knee during stair descent among female adolescents with patellofemoral pain (PFP) and to report its association with self-reported clinical status assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS)....

  6. Turbomachinery Fluid Mechanics and Control

    Science.gov (United States)

    2010-01-01

    ratio. Both the rotor and stator blade rows in an axial turbomachine diffuse their respective incoming flow fields. Therefore flow control technologies...in both cases, but are much more efficiently investigated in the stator blade row. 3 The blade rows in axial turbomachines are most accurately...Aeroacoustics & Aeroelasticity of Turbomachines , Sept 7-11, 2003 Duke University, Burham, NC. 39 Gorrell, S.E., Okiishi, T., and Copenhaver

  7. Doenças neuromusculares

    OpenAIRE

    Umbertina C. Reed

    2002-01-01

    Objetivo: apresentar os dados essenciais para o diagnóstico diferencial entre as principais doenças neuromusculares, denominação genérica sob a qual agrupam-se diferentes afecções, decorrentes do acometimento primário da unidade motora (motoneurônio medular, raiz nervosa, nervo periférico, junção mioneural e músculo). Fontes dos dados: os aspectos clínicos fundamentais para estabelecer o diagnóstico diferencial entre as diferentes doenças neuromusculares, bem como entre estas e as causas de h...

  8. Neuromuscular ultrasound of cranial nerves.

    Science.gov (United States)

    Tawfik, Eman A; Walker, Francis O; Cartwright, Michael S

    2015-04-01

    Ultrasound of cranial nerves is a novel subdomain of neuromuscular ultrasound (NMUS) which may provide additional value in the assessment of cranial nerves in different neuromuscular disorders. Whilst NMUS of peripheral nerves has been studied, NMUS of cranial nerves is considered in its initial stage of research, thus, there is a need to summarize the research results achieved to date. Detailed scanning protocols, which assist in mastery of the techniques, are briefly mentioned in the few reference textbooks available in the field. This review article focuses on ultrasound scanning techniques of the 4 accessible cranial nerves: optic, facial, vagus and spinal accessory nerves. The relevant literatures and potential future applications are discussed.

  9. Perceived pain and temporomandibular disorders in neuromuscular diseases.

    Science.gov (United States)

    Fischer, Michael J; Riedlinger, Kathrin; Schoser, Benedikt; Bernateck, Michael

    2009-10-01

    Little is known about pain associated with temporomandibular disorders (TMD) in neuromuscular diseases. Inpatients (N = 134) with neuromuscular disorder diagnoses were given questionnaires to estimate pain localization and intensity. Research Diagnostic Criteria for Temporomandibular Disorders and the Temporomandibular Index (TMI) were utilized to assess TMD. Pain was reported by 116 patients (86%). Legs (52%) and arms (33%) were the most common locations for pain localization, but the highest Pearson correlations (TMI vs. perceived pain) appeared for pain located in the trunk and arms (0.861, P < 0.01). No correlation between TMI and diagnosis group existed except for "acquired myopathy" and "miscellaneous neuromuscular diseases." These results suggest that the degree of TMD does not correlate with pain according to disease, although common mechanisms might be responsible for pain development in specific body regions connected with TMD. Most important, higher levels of TMD are associated with higher levels of perceived pain.

  10. Comparison of the effects of hamstring stretching using proprioceptive neuromuscular facilitation with prior application of cryotherapy or ultrasound therapy.

    Science.gov (United States)

    Magalhães, Francisco Elezier Xavier; Junior, Arlindo Rodrigues de Mesquita; Meneses, Harnold's Tyson de Sousa; Moreira Dos Santos, Rayele Pricila; Rodrigues, Ezaine Costa; Gouveia, Samara Sousa Vasconcelos; Gouveia, Guilherme Pertinni de Morais; Orsini, Marco; Bastos, Victor Hugo do Vale; Machado, Dionis de Castro Dutra

    2015-05-01

    [Purpose] Stretching using proprioceptive neuromuscular facilitation involve physiological reflex mechanisms through submaximal contraction of agonists which activate Golgi organ, promoting the relaxation reflex. The aim of this study was to evaluate the effects of proprioceptive neuromuscular facilitation alone and with prior application of cryotherapy and thermotherapy on hamstring stretching. [Subjects and Methods] The sample comprised of 32 young subjects with hamstring retraction of the right limb. The subjects were randomly allocated to four groups: the control, flexibility PNF, flexibility PNF associated with cryotherapy, flexibility PNF in association with ultrasound therapy. [Results] After 12 stretching sessions, experimental groups showed significant improvements compared to the control group. Moreover, we did not find any significant differences among the experimental groups indicating PNF stretching alone elicits similar results to PNF stretching with prior administration of cryotherapy or thermotherapy. [Conclusion] PNF without other therapy may be a more practical and less expensive choice for clinical care.

  11. Protein defects in neuromuscular diseases

    Directory of Open Access Journals (Sweden)

    Vainzof M.

    2003-01-01

    Full Text Available Muscular dystrophies are a heterogeneous group of genetically determined progressive disorders of the muscle with a primary or predominant involvement of the pelvic or shoulder girdle musculature. The clinical course is highly variable, ranging from severe congenital forms with rapid progression to milder forms with later onset and a slower course. In recent years, several proteins from the sarcolemmal muscle membrane (dystrophin, sarcoglycans, dysferlin, caveolin-3, from the extracellular matrix (alpha2-laminin, collagen VI, from the sarcomere (telethonin, myotilin, titin, nebulin, from the muscle cytosol (calpain 3, TRIM32, from the nucleus (emerin, lamin A/C, survival motor neuron protein, and from the glycosylation pathway (fukutin, fukutin-related protein have been identified. Mutations in their respective genes are responsible for different forms of neuromuscular diseases. Protein analysis using Western blotting or immunohistochemistry with specific antibodies is of the utmost importance for the differential diagnosis and elucidation of the physiopathology of each genetic disorder involved. Recent molecular studies have shown clinical inter- and intra-familial variability in several genetic disorders highlighting the importance of other factors in determining phenotypic expression and the role of possible modifying genes and protein interactions. Developmental studies can help elucidate the mechanism of normal muscle formation and thus muscle regeneration. In the last fifteen years, our research has focused on muscle protein expression, localization and possible interactions in patients affected by different forms of muscular dystrophies. The main objective of this review is to summarize the most recent findings in the field and our own contribution.

  12. Neuromuscular Electrical Stimulation for Motor Restoration in Hemiplegia.

    Science.gov (United States)

    Knutson, Jayme S; Fu, Michael J; Sheffler, Lynne R; Chae, John

    2015-11-01

    This article reviews the most common therapeutic and neuroprosthetic applications of neuromuscular electrical stimulation (NMES) for upper and lower extremity stroke rehabilitation. Fundamental NMES principles and purposes in stroke rehabilitation are explained. NMES modalities used for upper and lower limb rehabilitation are described, and efficacy studies are summarized. The evidence for peripheral and central mechanisms of action is also summarized.

  13. Neuromuscular and mitochondrial disorders: what is relevant to the anaesthesiologist?

    NARCIS (Netherlands)

    Driessen, J.J.

    2008-01-01

    PURPOSE OF REVIEW: The review provides an up-to-date information to the anaesthesiologist about the more frequent and important neuromuscular disorders for which new basic insights or clinical implications have been reported. RECENT FINDINGS: The findings include the mechanisms of the hyperkalemia a

  14. Neuromuscular Manifestations of West Nile Virus Infection

    Directory of Open Access Journals (Sweden)

    A. Arturo eLeis

    2012-03-01

    Full Text Available The most common neuromuscular manifestation of West Nile virus (WNV infection is a poliomyelitis syndrome with asymmetric paralysis variably involving one (monoparesis to four limbs (quadriparesis, with or without brainstem involvement and respiratory failure. This syndrome of acute flaccid paralysis may occur without overt fever or meningoencephalitis. Although involvement of anterior horn cells in the spinal cord and motor neurons in the brainstem are the major sites of pathology responsible for neuromuscular signs, inflammation also may involve skeletal or cardiac muscle (myositis, myocarditis, motor axons (polyradiculitis, peripheral nerve (Guillain-Barré syndrome, brachial plexopathy. In addition, involvement of spinal sympathetic neurons and ganglia provides a plausible explanation for autonomic instability seen in some patients. Many patients also experience prolonged subjective generalized weakness and disabling fatigue. Despite recent evidence that WNV may persist long term in the central nervous system or periphery in animals, the evidence in humans is controversial. WNV persistence would be of great concern in immunosuppressed patients or in those with prolonged or recurrent symptoms. Support for the contention that WNV can lead to autoimmune disease arises from reports of patients presenting with various neuromuscular diseases that presumably involve autoimmune mechanisms (GBS, other demyelinating neu¬ropathies, myasthenia gravis, brachial plexopathies, stiff-person syndrome, and delayed or recurrent symptoms. Although there is no specific treatment or vaccine currently approved in humans, and the standard remains supportive care, drugs that can alter the cascade of immunobiochemical events leading to neuronal death may be potentially useful (high-dose corticosteroids, interferon preparations, and intravenous immune globulin containing WNV-specific antibodies. Human experience with these agents seems promising based on anecdotal

  15. Vocational perspectives and neuromuscular disorders

    NARCIS (Netherlands)

    Andries, F; Wevers, CWJ; Wintzen, AR; Busch, HFM; Howeler, CJ; deJager, AEJ; Padberg, GW; deVisser, M; Wokke, JHJ

    1997-01-01

    The present study analyses the actual occupational situation, vocational handicaps and past labour career of a group of about 1000 Dutch patients suffering from a neuromuscular disorder (NMD). On the basis of the likelihood of a substantial employment history and sufficient numbers of patients, four

  16. Muscle ultrasound in neuromuscular disorders.

    NARCIS (Netherlands)

    Pillen, S.; Arts, I.M.P.; Zwarts, M.J.

    2008-01-01

    Muscle ultrasound is a useful tool in the diagnosis of neuromuscular disorders, as these disorders result in muscle atrophy and intramuscular fibrosis and fatty infiltration, which can be visualized with ultrasound. Several prospective studies have reported high sensitivities and specificities in th

  17. Role of Intrinsic and Reflexive Dynamics in the Control of Spinal Stability

    OpenAIRE

    Moorhouse, Kevin Michael

    2005-01-01

    Role of Intrinsic and Reflexive Dynamics in the Control of Spinal Stability Kevin M. Moorhouse Abstract Spinal stability describes the ability of the neuromuscular system to maintain equilibrium in the presence of kinematic and control variability, and may play an important role in the etiology of low-back disorders (LBDs). The primary mechanism for the neuromuscular control of spinal stability is the recruitment and control of active paraspinal muscle stiffness (i.e., trunk stif...

  18. Optimal Control of Active Recoil Mechanisms

    Science.gov (United States)

    1977-02-01

    pressures in different chambers, rod pull are available and can be plotted. A linear state feedback control system is proposed to adapt this...desirable. A linear state feedback control system with variable gains is proposed in the report. A separate control law is designed for each...optimization algorithm to choose a feasible solution. 27 3.3 Results for M-37 Recoil Mechanism The linear state feedback control system and

  19. Turning off the central contribution to contractions evoked by neuromuscular electrical stimulation.

    Science.gov (United States)

    Dean, J C; Yates, L M; Collins, D F

    2008-08-01

    Neuromuscular electrical stimulation can generate contractions through both peripheral and central mechanisms. The peripheral mechanism involves the direct activation of motor axons, while the central mechanism involves the activation of sensory axons that recruit spinal neurons through a reflex pathway. For use in functional electrical stimulation. One must have control over turning the central mechanism on and off. We investigated whether inhibition developed through antagonist muscle (tibialis anterior, TA) contractions elicited by electrical stimulation or by volition can turn off the central mechanism in triceps surae. Both electrical stimulation and voluntary contractions of TA reduced or eliminated plantar flexion torque produced by the central mechanism, indicating that inhibition induced via these contractions can effectively turn off the central contribution to force. These findings suggest that patterns of electrical stimulation may be able to generate periodic muscle contractions by turning the central contribution to muscular contractions on and off.

  20. Mechanics and aerodynamics of insect flight control.

    Science.gov (United States)

    Taylor, G K

    2001-11-01

    Insects have evolved sophisticated fight control mechanisms permitting a remarkable range of manoeuvres. Here, I present a qualitative analysis of insect flight control from the perspective of flight mechanics, drawing upon both the neurophysiology and biomechanics literatures. The current literature does not permit a formal, quantitative analysis of flight control, because the aerodynamic force systems that biologists have measured have rarely been complete and the position of the centre of gravity has only been recorded in a few studies. Treating the two best-known insect orders (Diptera and Orthoptera) separately from other insects, I discuss the control mechanisms of different insects in detail. Recent experimental studies suggest that the helicopter model of flight control proposed for Drosophila spp. may be better thought of as a facultative strategy for flight control, rather than the fixed (albeit selected) constraint that it is usually interpreted to be. On the other hand, the so-called 'constant-lift reaction' of locusts appears not to be a reflex for maintaining constant lift at varying angles of attack, as is usually assumed, but rather a mechanism to restore the insect to pitch equilibrium following a disturbance. Differences in the kinematic control mechanisms used by the various insect orders are related to differences in the arrangement of the wings, the construction of the flight motor and the unsteady mechanisms of lift production that are used. Since the evolution of insect flight control is likely to have paralleled the evolutionary refinement of these unsteady aerodynamic mechanisms, taxonomic differences in the kinematics of control could provide an assay of the relative importance of different unsteady mechanisms. Although the control kinematics vary widely between orders, the number of degrees of freedom that different insects can control will always be limited by the number of independent control inputs that they use. Control of the moments

  1. Mechanical engineers' handbook, design, instrumentation, and controls

    CERN Document Server

    Kutz, Myer

    2015-01-01

    Full coverage of electronics, MEMS, and instrumentation andcontrol in mechanical engineering This second volume of Mechanical Engineers' Handbookcovers electronics, MEMS, and instrumentation and control, givingyou accessible and in-depth access to the topics you'll encounterin the discipline: computer-aided design, product design formanufacturing and assembly, design optimization, total qualitymanagement in mechanical system design, reliability in themechanical design process for sustainability, life-cycle design,design for remanufacturing processes, signal processing, dataacquisition and dis

  2. Caffeine ingestion reverses the circadian rhythm effects on neuromuscular performance in highly resistance-trained men.

    Directory of Open Access Journals (Sweden)

    Ricardo Mora-Rodríguez

    Full Text Available PURPOSE: To investigate whether caffeine ingestion counteracts the morning reduction in neuromuscular performance associated with the circadian rhythm pattern. METHODS: Twelve highly resistance-trained men underwent a battery of neuromuscular tests under three different conditions; i morning (10:00 a.m. with caffeine ingestion (i.e., 3 mg kg(-1; AM(CAFF trial; ii morning (10:00 a.m. with placebo ingestion (AM(PLAC trial; and iii afternoon (18:00 p.m. with placebo ingestion (PM(PLAC trial. A randomized, double-blind, crossover, placebo controlled experimental design was used, with all subjects serving as their own controls. The neuromuscular test battery consisted in the measurement of bar displacement velocity during free-weight full-squat (SQ and bench press (BP exercises against loads that elicit maximum strength (75% 1RM load and muscle power adaptations (1 m s(-1 load. Isometric maximum voluntary contraction (MVC(LEG and isometric electrically evoked strength of the right knee (EVOK(LEG were measured to identify caffeine's action mechanisms. Steroid hormone levels (serum testosterone, cortisol and growth hormone were evaluated at the beginning of each trial (PRE. In addition, plasma norepinephrine (NE and epinephrine were measured PRE and at the end of each trial following a standardized intense (85% 1RM 6 repetitions bout of SQ (POST. RESULTS: In the PM(PLAC trial, dynamic muscle strength and power output were significantly enhanced compared with AM(PLAC treatment (3.0%-7.5%; p≤0.05. During AM(CAFF trial, muscle strength and power output increased above AM(PLAC levels (4.6%-5.7%; p≤0.05 except for BP velocity with 1 m s(-1 load (p = 0.06. During AM(CAFF, EVOK(LEG and NE (a surrogate of maximal muscle sympathetic nerve activation were increased above AM(PLAC trial (14.6% and 96.8% respectively; p≤0.05. CONCLUSIONS: These results indicate that caffeine ingestion reverses the morning neuromuscular declines in highly resistance

  3. Neuromuscular disruption with ultrashort electrical pulses

    Science.gov (United States)

    Pakhomov, Andrei; Kolb, Juergen F.; Joshi, Ravindra P.; Schoenbach, Karl H.; Dayton, Thomas; Comeaux, James; Ashmore, John; Beason, Charles

    2006-05-01

    Experimental studies on single cells have shown that application of pulsed voltages, with submicrosecond pulse duration and an electric field on the order of 10 kV/cm, causes sudden alterations in the intracellular free calcium concentration, followed by immobilization of the cell. In order to examine electrical stimulation and incapacitation with such ultrashort pulses, experiments on anesthetized rats have been performed. The effect of single, 450 nanosecond monopolar pulses have been compared with that of single pulses with multi-microsecond duration (TASER pulses). Two conditions were explored: 1. the ability to elicit a muscle twitch, and, 2. the ability to suppress voluntary movement by using nanosecond pulses. The second condition is relevant for neuromuscular incapacitation. The preliminary results indicate that for stimulation microsecond pulses are advantageous over nanosecond pulses, whereas for incapacitation, the opposite seems to apply. The stimulation effects seem to scale with electrical charge, whereas the disruption effects don't follow a simple scaling law. The increase in intensity (time of incapacitation) for a given pulse duration, is increasing with electrical energy, but is more efficient for nanosecond than for microsecond pulses. This indicates different cellular mechanisms for incapacitation, most likely subcellular processes, which have been shown to become increasingly important when the pulse duration is shortened into the nanosecond range. If further studies can confirm these initial results, consequences of reduced pulse duration are a reduction in weight and volume of the pulse delivery system, and likely, because of the lower required energy for neuromuscular incapacitation, reduced safety risks.

  4. Integrated design approach for controlled mechanical structures

    Energy Technology Data Exchange (ETDEWEB)

    Kiriazov, P. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Mechanics

    1998-10-01

    This study is addressed to design problems of controlled mechanical structures (CMS) like robot manipulators and engineering systems with active vibration control that may be subject to arbitrary disturbances. Along with the basic design requirement for strength/load capacity, additional design criteria for CMS are needed to meet the continuously increasing demands for faster response, improved precision and reduced energy consumption. As a CMS is a functionally directed assembly of mutually influencing components: control, actuator, mechanical, and sensor subsystems, a conceptual framework for their integrated design is required. Parameters of these subsystems influencing the dynamic performance of CMS define a matrix that transfers the control inputs into the controlled outputs (accelerations). This transfer matrix plays the key role in the integrated structure-control design. We consider the design optimization problem for CMS having decentralized control architecture. An integrated design criterion for such systems is proposed which is based on optimal trade-off relations between bounds of model uncertainties and control force limits. Optimizing this criterion leads to CMS with maximum degree of robustness. The approach proposed makes it possible a decomposition of the overall design problem into design problems for the CMS`s components. The design concepts are applied to the mechanical subsystem of planar linkage systems. Robust decentralized controllers are designed for a two-degree-of-freedom manipulator with elastic joints. (orig.)

  5. Neuromuscular Dysfunction in Experimental Sepsis and Glutamine

    Science.gov (United States)

    Çankayalı, İlkin; Boyacılar, Özden; Demirağ, Kubilay; Uyar, Mehmet; Moral, Ali Reşat

    2016-01-01

    Background: Electrophysiological studies show that critical illness polyneuromyopathy appears in the early stage of sepsis before the manifestation of clinical findings. The metabolic response observed during sepsis causes glutamine to become a relative essential amino acid. Aims: We aimed to assess the changes in neuromuscular transmission in the early stage of sepsis after glutamine supplementation. Study Design: Animal experimentation. Methods: Twenty male Sprague-Dawley rats were randomized into two groups. Rats in both groups were given normal feeding for one week. In the study group, 1 g/kg/day glutamine was added to normal feeding by feeding tube for one week. Cecal ligation and perforation (CLP) surgery was performed at the end of one week. Before and 24 hours after CLP, compound muscle action potentials were recorded from the gastrocnemius muscle. Results: Latency measurements before and 24 hours after CLP were 0.68±0.05 ms and 0.80±0.09 ms in the control group and 0.69±0.07 ms and 0.73±0.07 ms in the study group (p<0.05). Conclusion: Since enteral glutamine prevented compound muscle action potentials (CMAP) latency prolongation in the early phase of sepsis, it was concluded that enteral glutamine replacement might be promising in the prevention of neuromuscular dysfunction in sepsis; however, further studies are required. PMID:27308070

  6. Damage-mitigating control of mechanical systems

    Science.gov (United States)

    Holmes, Michael S.

    Damage-Mitigating Control is a field of research involving the integration of two distinct disciplines: Systems Sciences and Mechanics of Materials. This dissertation presents a feedback control architecture for mechanical systems to achieve a tradeoff between dynamic performance and structural durability of critical plant components. The proposed damage-mitigating control system has a two-tier structure: (i) A lower-level linear output feedback controller for plant output tracking and stability robustness over a specified operating range; and (ii) An upper-level nonlinear feedback controller which takes advantage of the real-time information generated by a physics-based model of material damage. The advantages and disadvantages of various methods available for the design of linear tracking controllers are discussed. A robust sampled-data Hsbinfty controller is designed for a reusable rocket engine, similar to the Space Shuttle Main Engine, based on a 2-input/2-output, 20-state model. The mu-synthesis technique is used to design a robust sampled-data controller for a commercial-scale fossil-fueled power plant based on a 4-input/4-output, 27-state model. A procedure for the design of damage-mitigating linear tracking controllers is also presented. The concept of fuzzy control is used to synthesize upper-level nonlinear feedback controllers based on real-time damage information. Damage-mitigating controllers are designed for the reusable rocket engine and the fossil-fueled power plant. A major advantage of using the fuzzy method for damage-mitigating controller design is that the controller can be synthesized without directly dealing with the inherent nonlinearities of the damage model. Simulation results for the reusable rocket engine and the fossil-fueled power plant suggest that the fuzzy method of damage mitigation is a practical way to design damage controllers for mechanical systems. The damage controller parameter optimization method is presented as an

  7. Nonsmooth mechanics models, dynamics and control

    CERN Document Server

    Brogliato, Bernard

    2016-01-01

    Now in its third edition, this standard reference is a comprehensive treatment of nonsmooth mechanical systems refocused to give more prominence to control and modelling. It covers Lagrangian and Newton–Euler systems, detailing mathematical tools such as convex analysis and complementarity theory. The ways in which nonsmooth mechanics influence and are influenced by well-posedness analysis, numerical analysis and simulation, modelling and control are explained. Contact/impact laws, stability theory and trajectory-tracking control are given in-depth exposition connected by a framework formed from complementarity systems and measure-differential inclusions. Links are established with electrical circuits with set-valued nonsmooth elements and with other nonsmooth dynamical systems like impulsive and piecewise linear systems. Nonsmooth Mechanics (third edition) has been substantially rewritten, edited and updated to account for the significant body of results that have emerged in the twenty-first century—incl...

  8. [Nitrogen metabolism and its control mechanisms].

    Science.gov (United States)

    Bergner, H

    1989-01-01

    N intake in the form of protein has neither got an upper nor a lower limit for agricultural working animals within a diet and there is no control mechanism for it. A high surplus of certain amino acids results in a reduction of feed intake. N excretion in faeces depends on 1) the excretion of N containing indigestible feedstuffs, 2) bacterial nitrogen synthesis in the large intestine and 3) the excretion of true endogenous N containing substances (digestion enzymes, intestinal epithelium, N containing endogenous secretion). There are no other control mechanisms for N excretion in faeces. N excretion in urine mainly comprises the nitrogen from the degeneration of amino acids and nucleic acids. The interrelations between urea, NH3, allantoin, creatine and creatinine, uric acid and hippuric acid depend on the species (monogastric or ruminants), on the nitrogen and N amount consumed and on the recycling ratio of the amino acids. The absolute amount of N excretion is not subject to any control mechanism, it depends on the intake of protein and NPN substances, the interim stages, however, which lead to the formation of excretory products, are intermediately controlled. The most important interim stage is protein biosynthesis, which is a fixed, intermediately controlled value in maintenance level. Under growth conditions only, the protein synthesis quota can exceed the protein degradation quota of the total organism (positive N balance). The control mechanisms of protein biosynthesis have, according to current knowledge, the following structure: Stimulation: 1) growth hormone (STH) stimulates protein synthesis by means of somatomedins; 2) hormones of the thyroid gland (T4 and T3) are controlled by the hormone stimulating the thyroid gland (TSH); 3) insulin. Inhibition: 1) somatostatin inhibits STH, TSH and insulin; 2) cortisol directly inhibits protein synthesis and stimulates protein degradation. The control mechanisms of protein turnover in addition to genetic coding

  9. The undesirable effects of neuromuscular blocking drugs

    DEFF Research Database (Denmark)

    Claudius, C; Garvey, L H; Viby-Mogensen, J

    2009-01-01

    Neuromuscular blocking drugs are designed to bind to the nicotinic receptor at the neuromuscular junction. However, they also interact with other acetylcholine receptors in the body. Binding to these receptors causes adverse effects that vary with the specificity for the cholinergic receptor...... in question. Moreover, all neuromuscular blocking drugs may cause hypersensitivity reactions. Often the symptoms are mild and self-limiting but massive histamine release can cause systematic reactions with circulatory and respiratory symptoms and signs. At the end of anaesthesia, no residual effect...... of a neuromuscular blocking drug should be present. However, the huge variability in response to neuromuscular blocking drugs makes it impossible to predict which patient will suffer postoperative residual curarization. This article discusses the undesirable effects of the currently available neuromuscular blocking...

  10. Exercise therapy and other types of physical therapy for patients with neuromuscular diseases: a systematic review.

    NARCIS (Netherlands)

    Cup, E.H.C.; Pieterse, A.J.; Broek-Pastoor, J.M. Ten; Munneke, M.; Engelen, B.G.M. van; Hendricks, H.T.; Wilt, G.J. van der; Oostendorp, R.A.B.

    2007-01-01

    OBJECTIVE: To summarize and critically appraise the available evidence on exercise therapy and other types of physical therapies for patients with neuromuscular diseases (NMD). DATA SOURCES: Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews, Medline, CINAHL,

  11. Comparison of effects of static, proprioceptive neuromuscular facilitation and Mulligan stretching on hip flexion range of motion: a randomized controlled trial.

    Science.gov (United States)

    Yıldırım, M S; Ozyurek, S; Tosun, Oç; Uzer, S; Gelecek, N

    2016-03-01

    The aim of this study was to compare the effects of static stretching, proprioceptive neuromuscular facilitation (PNF) stretching and Mulligan technique on hip flexion range of motion (ROM) in subjects with bilateral hamstring tightness. A total of 40 students (mean age: 21.5±1.3 years, mean body height: 172.8±8.2 cm, mean body mass index: 21.9±3.0 kg · m(-2)) with bilateral hamstring tightness were enrolled in this randomized trial, of whom 26 completed the study. Subjects were divided into 4 groups performing (I) typical static stretching, (II) PNF stretching, (III) Mulligan traction straight leg raise (TSLR) technique, (IV) no intervention. Hip flexion ROM was measured using a digital goniometer with the passive straight leg raise test before and after 4 weeks by two physiotherapists blinded to the groups. 52 extremities of 26 subjects were analyzed. Hip flexion ROM increased in all three intervention groups (pMulligan TSLR technique in comparison to typical static stretching (p=0.016 and p=0.02, respectively). No significant difference was found between Mulligan TSLR technique and PNF stretching (p=0.920). The initial-final assessment difference of hip flexion ROM was similar in typical static stretching and no intervention (p=0.491). A 4-week stretching intervention is beneficial for increasing hip flexion ROM in bilateral hamstring tightness. However, PNF stretching and Mulligan TSLR technique are superior to typical static stretching. These two interventions can be alternatively used for stretching in hamstring tightness.

  12. Controllability for single-input mechanical control systems with dissipation

    Institute of Scientific and Technical Information of China (English)

    Jianling KANG; Hong WANG; Huawen YE

    2005-01-01

    Within the affine connection framework of Lagrangian control systems,based on the results of Sussmann on small-time locally controllability of single-input affine nonlinear control systems,the controllability results for mechanical control systems with single-input are extended to the case of the systems with isotropic damping,where the Lagrangian is the kinetic energy associated with a Riemannian metric.A sufficient condition of negative small-time locally controllability for the system is obtained.Then,it is demonstrated that such systems are small-time locally configuration controllable if and only if the dimension of the configuration manifold is one.Finally,two examples are given to illustrate the results.Lie bracketting of vector fields and the symmetric product show the advantages in the discussion.

  13. Notions of controllability for quantum mechanical systems

    CERN Document Server

    Albertini, F

    2001-01-01

    In this paper, we define four different notions of controllability of physical interest for multilevel quantum mechanical systems. These notions involve the possibility of driving the evolution operator as well as the state of the system. We establish the connections among these different notions as well as methods to verify controllability. The paper also contains results on the relation between the controllability in arbitrary small time of a system varying on a compact transformation Lie group and the corresponding system on the associated homogeneous space. As an application, we prove that, for the system of two interacting spin 1/2 particles, not every state transfer can be obtained in arbitrary small time.

  14. Stress controls the mechanics of collagen networks.

    Science.gov (United States)

    Licup, Albert James; Münster, Stefan; Sharma, Abhinav; Sheinman, Michael; Jawerth, Louise M; Fabry, Ben; Weitz, David A; MacKintosh, Fred C

    2015-08-04

    Collagen is the main structural and load-bearing element of various connective tissues, where it forms the extracellular matrix that supports cells. It has long been known that collagenous tissues exhibit a highly nonlinear stress-strain relationship, although the origins of this nonlinearity remain unknown. Here, we show that the nonlinear stiffening of reconstituted type I collagen networks is controlled by the applied stress and that the network stiffness becomes surprisingly insensitive to network concentration. We demonstrate how a simple model for networks of elastic fibers can quantitatively account for the mechanics of reconstituted collagen networks. Our model points to the important role of normal stresses in determining the nonlinear shear elastic response, which can explain the approximate exponential relationship between stress and strain reported for collagenous tissues. This further suggests principles for the design of synthetic fiber networks with collagen-like properties, as well as a mechanism for the control of the mechanics of such networks.

  15. Facial rehabilitation: a neuromuscular reeducation, patient-centered approach.

    Science.gov (United States)

    Vanswearingen, Jessie

    2008-05-01

    Individuals with facial paralysis and distorted facial expressions and movements secondary to a facial neuromotor disorder experience substantial physical, psychological, and social disability. Previously, facial rehabilitation has not been widely available or considered to be of much benefit. An emerging rehabilitation science of neuromuscular reeducation and evidence for the efficacy of facial neuromuscular reeducation, a process of facilitating the return of intended facial movement patterns and eliminating unwanted patterns of facial movement and expression, may provide patients with disorders of facial paralysis or facial movement control opportunity for the recovery of facial movement and function. We provide a brief overview of the scientific rationale for facial neuromuscular reeducation in the structure and function of the facial neuromotor system, the neuropsychology of facial expression, and relations among expressions, movement, and emotion. The primary purpose is to describe principles of neuromuscular reeducation, assessment and outcome measures, approach to treatment, the process, including surface-electromyographic biofeedback as an adjunct to reeducation, and the goal of enhancing the recovery of facial expression and function in a patient-centered approach to facial rehabilitation.

  16. Control of Compliant Mechanisms with Large Deflections

    Science.gov (United States)

    Kern, D.; Bauer, J.; Seemann, W.

    Very often elastic joints are used in high precision applications. In the case of rotational joints flexure hinges do have some advantages compared to conventional ones. However, the most important disadvantages are the complicated and complex kinematics and kinetics. As consequence, the control of mechanisms comprised of flexure hinges gets more difficult. The strategy pursued here is to reduce flexure hinges to pseudo rigid-body systems that fit into the elaborated framework of multi-body dynamics, in particular pre-control in combination with a feedback controller. The inherent deviations of these reduced models are described as uncertainties. Methods from robust control are used to synthesize controllers for such systems with uncertainty. The procedure is illustrated by examining an example of a single flexure hinge (leaf spring type).

  17. Contribución del soporte nutricional al tratamiento de las alteraciones neuro-musculares del paciente crítico Contribution of nutritional support to treatment neuromuscular impairments of critically ill patients

    Directory of Open Access Journals (Sweden)

    J. C. Montejo González

    2006-05-01

    Full Text Available Las alteraciones neuromusculares que tienen lugar en el paciente crítico han sido atribuidas a factores como la situación séptica, la liberación de mediadores inflamatorioso el empleo de fármacos que afectan desfavorablemente a la función neuro-muscular. El papel de factores metabólicos y nutricionales en el desarrollo de esta patología ha recibido poca atención. En la actualidad, el empleo de protocolos de control intensivo de la glucemia podría tener gran interés en la prevención de las alteraciones neuro-musculares de los pacientes críticos. Los mecanismos exactos de la implicación de la hiperglucemia en esta patología son, todavía, desconocidos, aunque la evidencia de los datos procedentes de la investigación es importante. La miopatía caquectizante (atrofia muscular tiene lugar de manera habitual como consecuencia de los cambios obligados por la respuesta metabólica al estrés. El efecto del aporte de nutrientes sobre la ganancia de masa muscular es muy limitado, por lo que deben estudiarse otras acciones dirigidas a recuperar, de manera más rápida, la masa muscular perdida. Deben evitarse pautas agresivas de renutrición con objeto de prevenir el síndrome de realimentación y el consiguiente mayor deterioro de la función muscular. El aporte de substratos específicos, como la glutamina, podría tener un efecto beneficioso en la recuperación de las alteraciones neuro-musculares del paciente crítico. No obstante, no existen aún datos para justificar su empleo si el único objetivo es la recuperación de la función neuro-muscular.Neuromuscular impairments occurring in the critically ill patient have been attributed to factors such as sepsis, release of inflammatory mediators, or the use of drugs unfavorably affecting neuromuscular function. The role of metabolic and nutritional factors in the development of this condition has received little attention. Currently, the use of protocols of intensive glycemia monitoring

  18. Reactive Balance Control in Response to Perturbation in Unilateral Stance: Interaction Effects of Direction, Displacement and Velocity on Compensatory Neuromuscular and Kinematic Responses.

    Directory of Open Access Journals (Sweden)

    Kathrin Freyler

    Full Text Available Unexpected sudden perturbations challenge postural equilibrium and require reactive compensation. This study aimed to assess interaction effects of the direction, displacement and velocity of perturbations on electromyographic (EMG activity, centre of pressure (COP displacement and joint kinematics to detect neuromuscular characteristics (phasic and segmental and kinematic strategies of compensatory reactions in an unilateral balance paradigm. In 20 subjects, COP displacement and velocity, ankle, knee and hip joint excursions and EMG during short (SLR, medium (MLR and long latency response (LLR of four shank and five thigh muscles were analysed during random surface translations varying in direction (anterior-posterior (sagittal plane, medial-lateral (frontal plane, displacement (2 vs. 3 cm and velocity (0.11 vs. 0.18 m/s of perturbation when balancing on one leg on a movable platform. Phases: SLR and MLR were scaled to increased velocity (P<0.05; LLR was scaled to increased displacement (P<0.05. Segments: phasic interrelationships were accompanied by segmental distinctions: distal muscles were used for fast compensation in SLR (P<0.05 and proximal muscles to stabilise in LLR (P<0.05. Kinematics: ankle joints compensated for both increasing displacement and velocity in all directions (P<0.05, whereas knee joint deflections were particularly sensitive to increasing displacement in the sagittal (P<0.05 and hip joint deflections to increasing velocity in the frontal plane (P<0.05. COP measures increased with increasing perturbation velocity and displacement (P<0.05. Interaction effects indicate that compensatory responses are based on complex processes, including different postural strategies characterised by phasic and segmental specifications, precisely adjusted to the type of balance disturbance. To regain balance after surface translation, muscles of the distal segment govern the quick regain of equilibrium; the muscles of the proximal limb

  19. Fully Mechanically Controlled Automated Electron Microscopic Tomography

    Science.gov (United States)

    Liu, Jinxin; Li, Hongchang; Zhang, Lei; Rames, Matthew; Zhang, Meng; Yu, Yadong; Peng, Bo; Celis, César Díaz; Xu, April; Zou, Qin; Yang, Xu; Chen, Xuefeng; Ren, Gang

    2016-07-01

    Knowledge of three-dimensional (3D) structures of each individual particles of asymmetric and flexible proteins is essential in understanding those proteins’ functions; but their structures are difficult to determine. Electron tomography (ET) provides a tool for imaging a single and unique biological object from a series of tilted angles, but it is challenging to image a single protein for three-dimensional (3D) reconstruction due to the imperfect mechanical control capability of the specimen goniometer under both a medium to high magnification (approximately 50,000–160,000×) and an optimized beam coherence condition. Here, we report a fully mechanical control method for automating ET data acquisition without using beam tilt/shift processes. This method could reduce the accumulation of beam tilt/shift that used to compensate the error from the mechanical control, but downgraded the beam coherence. Our method was developed by minimizing the error of the target object center during the tilting process through a closed-loop proportional-integral (PI) control algorithm. The validations by both negative staining (NS) and cryo-electron microscopy (cryo-EM) suggest that this method has a comparable capability to other ET methods in tracking target proteins while maintaining optimized beam coherence conditions for imaging.

  20. Concurrency Control Mechanism of Complex Objects

    Institute of Scientific and Technical Information of China (English)

    徐庆云; 王能斌

    1992-01-01

    A complex object is an abstraction and description of a complex entity of the real world.Many applications in such domains as CIMS,CAD and OA define and manipulate a complex object as a single unit.In this paper,a definition of the model of complex objects is given,and the concurrency control mechanism of complex objects in WHYMX object-oriented database system is described.

  1. Development of Mechanical Water Level Controller

    OpenAIRE

    Akonyi Nasiru Sule; Chinedu Cletus Obinwa; Christian Ebele Okekeze; Eyo Ifreke

    2012-01-01

    The automatic water level controller is a device designed to regulate automatically the pumping of water to an overhead tank without allowing the water in the tank to be exhausted. The design of this mechanical device was achieved using the Archimedes principle of floatation; having a float which determines the water level in the tank depending on the choice of the minimum (lower) and maximum (upper) level inscribed in the tank. The fundamental attribute of this device is the ease in design, ...

  2. Computed tomography of skeletal muscles in neuromuscular disease

    Energy Technology Data Exchange (ETDEWEB)

    Rodiek, S.O.; Kuether, G.

    1985-06-01

    CT-documentation of skeletal muscular lesions caused by neuromuscular diseases implies an essential contribution to conventional techniques in the macroscopic field. Size, distribution and degree of lesions as well as compensatory mechanisms are proved thereby. We report about the different effects on muscle appearance referring to 106 patients of our own experience in amyotrophic lateral sclerosis, spinal muscular atrophy, poliomyelitis, polyradiculitis, polyneuropathy as well as peripheral traumatic nerve lesions.

  3. Neuromuscular impairment following backpack load carriage.

    Science.gov (United States)

    Blacker, Sam D; Fallowfield, Joanne L; Bilzon, James L J; Willems, Mark E T

    2013-01-01

    Load Carriage using backpacks is an occupational task and can be a recreational pursuit. The aim of this study was to investigate the mechanisms responsible for changes in neuromuscular function of the m. quadriceps femoris following load carriage. The physiological responses of 10 male participants to voluntary and electrically stimulated isometric contractions were measured before and immediately after two hours of treadmill walking at 6.5 km•h(-1) during level walking with no load [LW], and level walking with load carriage (25 kg backpack) [LC]. Maximal voluntary contraction force decreased by 15 ± 11 % following LC (p=0.006), with no change following LW (p=0.292). Voluntary activation decreased after LW and LC (p=0.033) with no difference between conditions (p=0.405). Doublet contraction time decreased after both LW and LC (p=0.002), with no difference between conditions (p=0.232). There were no other changes in electrically invoked doublet parameters in either condition. The 20:50 Hz ratio did not change following LW (p=0.864) but decreased from 0.88 ± 0.04 to 0.84 ± 0.04 after LC (p=0.011) indicating reduced Ca2+ release from the sarcoplasmic reticulum during excitation contraction coupling. In conclusion, two hours of load carriage carrying a 25 kg back pack caused neuromuscular impairment through a decrease in voluntary activation (i.e. central drive) and fatigue or damage to the peripheral muscle, including impairment of the excitation contraction coupling process. This may reduce physical performance and increase the risk of musculoskeletal injury.

  4. Intravenous immunoglobulin in the treatment of autoimmune neuromuscular diseases: present status and practical therapeutic guidelines.

    Science.gov (United States)

    Dalakas, M C

    1999-11-01

    This review summarizes the current status of intravenous immunoglobulin (IVIg) in the treatment of autoimmune neuromuscular disorders and the possible mechanisms of action of the drug based on work in vivo, in vitro, and in animal models. Supply of idiotypic antibodies, suppression of antibody production, or acceleration of catabolism of immunoglobulin G (IgG) are relevant in explaining the efficacy of IVIg in myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS), and antibody-mediated neuropathies. Suppression of pathogenic cytokines has putative relevance in inflammatory myopathies and demyelinating neuropathies. Inhibition of complement binding and prevention of membranolytic attack complex (MAC) formation are relevant in dermatomyositis (DM), Guillain-Barré syndrome (GBS), and MG. Modulation of Fc receptors or T-cell function is relevant in chronic inflammatory demyelinating polyneuropathy (CIDP), GBS, and inflammatory myopathies. The clinical efficacy of IVIg, based on controlled clinical trials conducted in patients with GBS, CIDP, multifocal motor neuropathy (MMN), DM, MG, LEMS, paraproteinemic IgM anti-myelin-associated glycoprotein (anti-MAG) demyelinating polyneuropathies, and inclusion body myositis is summarized and practical issues related to each disorder are addressed. The present role of IVIg therapy in other disorders based on small controlled or uncontrolled trials is also summarized. Finally, safety issues, risk factors, adverse reactions, spurious results or serological tests, and practical guidelines associated with the administration of IVIg in the treatment of neuromuscular disorders are presented.

  5. New Interference Mechanism Controls Ultracold Chemistry

    Science.gov (United States)

    Kendrick, Brian K.; Hazra, Jisha; Balakrishnan, N.

    2016-05-01

    A newly discovered interference mechanism has been shown to control the outcome of ultracold chemical reactions. The mechanism originates from the unique properties associated with ultracold collisions, namely: (1) isotropic (s-wave) scattering and (2) an effective quantization of the scattering phase shift (which originates from the bound state structure of the molecule). These two properties can lead to maximum constructive or destructive interference between two interfering reaction pathways (such as exchange and non-exchange in systems with two or more identical nuclei). If the molecular system exhibits a conical intersection, then the associated geometric phase is shown to act as a ``quantum switch'' which can turn the reactivity on or off. Reaction rate coefficients for the O + OH --> H + O2 and H + H2, reactions are presented which explicitly demonstrate the effect. Experimentalists might exploit this new mechanism to control ultracold reactions by the application of external electric or magnetic fields or by the selection of a particular nuclear spin state. This work was supported in part by the LDRD program (Grant No. 20140309ER) at LANL (B.K.) and by NSF Grant PHY-1505557 (N.B.) and ARO MURI Grant No. W911NF-12-1-0476 (N.B.).

  6. Control mechanisms in mitochondrial oxidative phosphorylation

    Institute of Scientific and Technical Information of China (English)

    Jana Hroudová; Zdeněk Fi(s)ar

    2013-01-01

    Distribution and activity of mitochondria are key factors in neuronal development, synaptic plasticity and axogenesis. The majority of energy sources, necessary for cellular functions, originate from oxidative phosphorylation located in the inner mitochondrial membrane. The adenosine-5'- triphosphate production is regulated by many control mechanism–firstly by oxygen, substrate level, adenosine-5'-diphosphate level, mitochondrial membrane potential, and rate of coupling and proton leak. Recently, these mechanisms have been implemented by "second control mechanisms," such as reversible phosphorylation of the tricarboxylic acid cycle enzymes and electron transport chain complexes, allosteric inhibition of cytochrome c oxidase, thyroid hormones, effects of fatty acids and uncoupling proteins. Impaired function of mitochondria is implicated in many diseases ranging from mitochondrial myopathies to bipolar disorder and schizophrenia. Mitochondrial dysfunctions are usually related to the ability of mitochondria to generate adenosine-5'-triphosphate in response to energy demands. Large amounts of reactive oxygen species are released by defective mitochondria, similarly, decline of antioxidative enzyme activities (e.g. in the elderly) enhances reactive oxygen species production. We reviewed data concerning neuroplasticity, physiology, and control of mitochondrial oxidative phosphorylation and reactive oxygen species production.

  7. Stirling engine control mechanism and method

    Science.gov (United States)

    Dineen, John J.

    1983-01-01

    A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion.

  8. Early appearance and possible roles of non-neuromuscular cholinesterases.

    Directory of Open Access Journals (Sweden)

    Carla eFalugi

    2012-04-01

    Full Text Available The biological function of the cholinesterase (ChE enzymes is well known and has been studied since the beginning of the XXth century; in particular, acetylcholinesterase (AChE, E.C. 3.1.1.7 is an enzyme playing a key role in the modulation of neuromuscular impulse transmission. However, in the past decades, there has been increasing interest concerning its role in regulating non-neuromuscular cell-to-cell interactions mediated by intracellular ion concentration changes, like the ones occurring during gamete interaction and embryonic development. An understanding of the mechanisms of the cholinergic regulation of these events can help us foresee the possible impact on environmental and human health, including gamete efficiency and possible teratogenic effects on different models, and help elucidate the extent to which exposure to ChE inhibitors may affect human health.

  9. Development of Mechanical Water Level Controller

    Directory of Open Access Journals (Sweden)

    Akonyi Nasiru Sule

    2012-10-01

    Full Text Available The automatic water level controller is a device designed to regulate automatically the pumping of water to an overhead tank without allowing the water in the tank to be exhausted. The design of this mechanical device was achieved using the Archimedes principle of floatation; having a float which determines the water level in the tank depending on the choice of the minimum (lower and maximum (upper level inscribed in the tank. The fundamental attribute of this device is the ease in design, fabrication and mounting at a lower cost. Its testing had shown and proved that it works efficiently with Archimedes’ principle of floatation. This eliminates the frequent human intervention/monitoring of the water level in the overhead tank to control overflow manually, thereby eliminating water and energy wastages.

  10. Pneumatic, PLC Controlled, Automotive Gear Shifting Mechanism

    Directory of Open Access Journals (Sweden)

    Muntaser Momani

    2010-05-01

    Full Text Available In this study, a gear shifting mechanism was designed and applied to make the shifting process faster and less destructible for the driver. The new device must be reliable, has a small dimensions, low construction and maintenance cost. This paper aims to improve gear shifting process using devices as: a manual four speed gear box, four pneumatic double acting cylinders, four pneumatic two position five ways directional control valves, Programmable Logic Controller (PLC LOGO unit, an electrical motor, an electrical clutch, a belt, two pulleys, limit switches, push buttons, bulbs, a table (holder and power supply. According to suggested gear_ shifting method the driver can select the transmission gear ratio without moving his hands from the steering wheel by putting the gear shifting push buttons on the steering wheel. Using this method leaves to the driver the excitement of choosing the shifting moment.

  11. Dynamic Discontinuous Control for Active Control of Mechanical Vibrations

    Directory of Open Access Journals (Sweden)

    Orestes Llanes Santiago

    2010-02-01

    Full Text Available This article shows the use of the discontinuous control using dynamic sliding modes for the active isolation of vibrations in mechanical systems. This type of control law constitutes a robust feedback control policy due to its insensitivity to external disturbance inputs, certain immunity to model parameter variations, within known bounds, and to the ever present modelling errors.  The whole theoretical analysis is applied to a lineal model of two degrees of freedom of the vehicle's suspension where the irregularities of the land represent of direct  way the external interferences to the system . To carry out the isolation an electro-hydraulic operator it is used. Simulations are performed which validate the proposed approach.

  12. Gain control mechanisms in spinal motoneurons

    Directory of Open Access Journals (Sweden)

    Michael David Johnson

    2014-07-01

    Full Text Available Motoneurons provide the only conduit for motor commands to reach muscles. For many years, motoneurons were in fact considered to be little more than passive wires. Systematic studies in the past 25 years however have clearly demonstrated that the intrinsic electrical properties of motoneurons are under strong neuromodulatory control via multiple sources. The discovery of potent neuromodulation from the brainstem and its ability to change the gain of motoneurons shows that the passive view of the motor output stage is no longer tenable. A mechanism for gain control at the motor output stage makes good functional sense considering our capability of generating an enormous range of forces, from very delicate (e.g. putting in a contact lens to highly forceful (emergency reactions. Just as sensory systems need gain control to deal with a wide dynamic range of inputs, so to might motor output need gain control to deal with the wide dynamic range of the normal movement repertoire. Two problems emerge from the potential use of the brainstem monoaminergic projection to motoneurons for gain control. First, the projection is highly diffuse anatomically, so that independent control of the gains of different motor pools is not feasible. In fact, the system is so diffuse that gain for all the motor pools in a limb likely increases in concert. Second, if there is a system that increases gain, probably a system to reduce gain is also needed. In this review, we summarize recent studies that show local inhibitory circuits within the spinal cord, especially reciprocal and recurrent inhibition, have the potential to solve both of these problems as well as constitute another source of gain modulation.

  13. The effects of roxatidine on neuromuscular transmission.

    Science.gov (United States)

    Bossa, R; Chiericozzi, M; Galatulas, I; Salvatore, G; Teli, M; Baggio, G; Castelli, M

    1995-01-01

    We have investigated the effects of the H2 receptor antagonist roxatidine on the neuromuscular transmission by using the sciatic nerve-gastrocnemius muscle preparation of the rat in vivo. Roxatidine, administered by i.v. injection, potentiates the neuromuscular blockade induced by d-tubocurarine, pancuronium and aminoglycoside antibiotic, kanamycin. Moreover, the drug alone is capable of producing a blockade on the preparation stimulated at high frequency. The neuromuscular blockade induced by roxatidine is partially reversed by 4-aminopyridine but not by dimaprit.

  14. Stance control knee mechanism for lower-limb support in hybrid neuroprosthesis

    Directory of Open Access Journals (Sweden)

    Curtis S. To, PhD

    2011-08-01

    Full Text Available A hydraulic stance control knee mechanism (SCKM was developed to fully support the knee against flexion during stance and allow uninhibited motion during swing for individuals with paraplegia using functional neuromuscular stimulation (FNS for gait assistance. The SCKM was optimized for maximum locking torque for body-weight support and minimum resistance when allowing for free knee motion. Ipsilateral and contralateral position and force feedback were used to control the SCKM. Through bench and nondisabled testing, the SCKM was shown to be capable of supporting up to 70 N-m, require no more than 13% of the torque achievable with FNS to facilitate free motion, and responsively and repeatedly unlock under an applied flexion knee torque of up to 49 N-m. Preliminary tests of the SCKM with an individual with paraplegia demonstrated that it could support the body and maintain knee extension during stance without the stimulation of the knee extensor muscles. This was achieved without adversely affecting gait, and knee stability was comparable to gait assisted by knee extensor stimulation during stance.

  15. Dynamic congestion control mechanisms for MPLS networks

    Science.gov (United States)

    Holness, Felicia; Phillips, Chris I.

    2001-02-01

    Considerable interest has arisen in congestion control through traffic engineering from the knowledge that although sensible provisioning of the network infrastructure is needed, together with sufficient underlying capacity, these are not sufficient to deliver the Quality of Service required for new applications. This is due to dynamic variations in load. In operational Internet Protocol (IP) networks, it has been difficult to incorporate effective traffic engineering due to the limited capabilities of the IP technology. In principle, Multiprotocol Label Switching (MPLS), which is a connection-oriented label swapping technology, offers new possibilities in addressing the limitations by allowing the operator to use sophisticated traffic control mechanisms. This paper presents a novel scheme to dynamically manage traffic flows through the network by re-balancing streams during periods of congestion. It proposes management-based algorithms that will allow label switched routers within the network to utilize mechanisms within MPLS to indicate when flows are starting to experience frame/packet loss and then to react accordingly. Based upon knowledge of the customer's Service Level Agreement, together with instantaneous flow information, the label edge routers can then instigate changes to the LSP route and circumvent congestion that would hitherto violate the customer contacts.

  16. Supervised neuromuscular exercise prior to hip and knee replacement

    DEFF Research Database (Denmark)

    Fernandes, Linda; Roos, Ewa M; Overgaard, Søren

    2017-01-01

    BACKGROUND: There are indications of beneficial short-term effect of pre-operative exercise in reducing pain and improving activity of daily living after total hip replacement (THR) and total knee replacement (TKR) surgery. Though, information from studies conducting longer follow-ups and economic...... evaluations of exercise prior to THR and TKR is needed. The aim of the study was to analyse 12-month clinical effect and cost-utility of supervised neuromuscular exercise prior to THR and TKR surgery. METHODS: The study was conducted alongside a randomised controlled trial including 165 patients scheduled...... for standard THR or TKR at a hospital located in a rural area of Denmark. The patients were randomised to replacement surgery with or without an 8-week preoperative supervised neuromuscular exercise program (Clinical Trials registration no.: NCT01003756). Clinical effect was measured with Hip disability...

  17. Effects of strength and power training on neuromuscular variables in older adults.

    Science.gov (United States)

    Wallerstein, Lilian França; Tricoli, Valmor; Barroso, Renato; Rodacki A, L F; Russo, Luciano; Aihara, André Yui; da Rocha Correa Fernandes, Artur; de Mello, Marco Tulio; Ugrinowitsch, Carlos

    2012-04-01

    The purpose of this study was to compare the neuromuscular adaptations produced by strength-training (ST) and power-training (PT) regimens in older individuals. Participants were balanced by quadriceps cross-sectional area (CSA) and leg-press 1-repetition maximum and randomly assigned to an ST group (n = 14; 63.6 ± 4.0 yr, 79.7 ± 17.2 kg, and 163.9 ± 9.8 cm), a PT group (n = 16; 64.9 ± 3.9 yr, 63.9 ± 11.9 kg, and 157.4 ± 7.7 cm), or a control group (n = 13; 63.0 ± 4.0 yr, 67.2 ± 10.8 kg, and 159.8 ± 6.8 cm). ST and PT were equally effective in increasing (a) maximum dynamic and isometric strength (p < .05), (b) increasing quadriceps muscle CSA (p < .05), and (c) decreasing electrical mechanical delay of the vastus lateralis muscle (p < .05). There were no significant changes in neuromuscular activation after training. The novel finding of the current study is that PT seems to be an attractive alternative to regular ST to maintain and improve muscle mass.

  18. Neuromuscular alterations in the dilated ileum of an adult patient with segmental lymphangiectasia.

    Science.gov (United States)

    Paggi, Silvia; Ferrero, Stefano; Braidotti, Paola; de Rai, Paolo; Conte, Dario; Basilisco, Guido

    2008-09-01

    Intestinal lymphangiectasia is a rare condition, which is characterized by the dilation of small bowel lymphatics and presents with signs and symptoms of protein-losing enteropathy. Some patients have complained of occlusive symptoms attributable to the mechanical obstruction caused by the considerable mucosal edema associated with the lymphatic dilation. On the basis of the hypothesis that alterations in the neuromuscular structures controlling clearance function or gut tone may play a role in ileal dilation, we examined the resected ileum of a 48-year-old male patient with segmental lymphangiectasia histologically, immunohistochemically (for S100 protein, PGP 9.5, Bcl-2, neuron-specific enolase, neurofilaments, synaptophysin, and CD117/C-kit), and by means of electron microscopy. Histology showed pseudocystic dilation of the mucosal, submucosal, and muscular lymphatics with fragmentation of the circular and longitudinal muscle layers. Hardly any neural expression of synaptophysin was observed, but the neural structures were otherwise morphologically normal and reacted normally to the other neural markers. This case shows that neuromuscular alterations can be found in the dilated ileum of patients with segmental lymphangiectasia.

  19. Smartphone app design for the wireless control of a neuromuscular electrical stimulator device with integrated randomization allocation process for RCT applications.

    Science.gov (United States)

    Sweeney, Dean; Quinlan, Leo R; OLaighin, Gearoid

    2015-08-01

    The use of NMES has evolved over the last five decades. Technological advancements have transformed these once complex systems into user-friendly devices with enhanced control functions, leading to new applications of NMES being investigated. The use of Randomized Control Trial (RCT) methodology in evaluating the effectiveness of new and existing applications of NMES is a demanding process adding time and cost to a translation into clinical practice. Poor quality trials may result in poor evidence of NMES effectiveness. In this paper some of the key challenges encountered in NMES clinical trials are identified with the aim of purposing a solution to address these challenges through the adoption of Smartphone technology. The design and evaluation of a smartphone application to provide automatic blind randomization control and facilitating the wireless temporal control of a portable Bluetooth enabled NMES is presented.

  20. Changes of trabecular bone under control of biologically mechanical mechanism

    Science.gov (United States)

    Wang, C.; Zhang, C. Q.; Dong, X.; Wu, H.

    2008-10-01

    In this study, a biological process of bone remodeling was considered as a closed loop feedback control system, which enables bone to optimize and renew itself over a lifetime. A novel idea of combining strain-adaptive and damage-induced remodeling algorithms at Basic Multicellular Unit (BMU) level was introduced. In order to make the outcomes get closer to clinical observation, the stochastic occurrence of microdamage was involved and a hypothesis that remodeling activation probability is related to the value of damage rate was assumed. Integrated with Finite Element Analysis (FEA), the changes of trabecular bone in morphology and material properties were simulated in the course of five years. The results suggest that deterioration and anisotropy of trabecluar bone are inevitable with natural aging, and that compression rather than tension can be applied to strengthen the ability of resistance to fracture. This investigation helps to gain more insight the mechanism of bone loss and identify improved treatment and prevention for osteoporosis or stress fracture.

  1. Electrophysiology of autonomic neuromuscular transmission involving ATP.

    Science.gov (United States)

    Sneddon, P

    2000-07-01

    Electrophysiological investigations of autonomic neuromuscular transmission have provided great insights into the role of ATP as a neurotransmitter. Burnstock and Holman made the first recordings of excitatory junction potentials (e.j.p.s) produced by sympathetic nerves innervating the smooth muscle of the guinea-pig vas deferens. This led to the identification of ATP as the mediator of e.j.p.s in this tissue, where ATP acts as a cotransmitter with noradrenaline. The e.j.p.s are mediated solely by ATP acting on P2X(1) receptors leading to action potentials and a rapid phasic contraction, whilst noradrenaline mediates a slower, tonic contraction which is not dependent on membrane depolarisation. Subsequent electrophysiological studies of the autonomic innervation of smooth muscles of the urogenital, gastrointestinal and cardiovascular systems have revealed a similar pattern of response, where ATP mediates a fast electrical and mechanical response, whilst another transmitter such as noradrenaline, acetylcholine, nitric oxide or a peptide mediates a slower response. The modulation of junction potentials by a variety of pre-junctional receptors and the mechanism of inactivation of ATP as a neurotransmitter will also be described.

  2. Clinical applications of immunoglobulin in neuromuscular diseases: focus on inflammatory myopathies

    Directory of Open Access Journals (Sweden)

    Paulo Victor Sgobbi de Souza

    2014-12-01

    Full Text Available During recent years, an increasing number of neuromuscular diseases have been recognized either to be caused primarily by autoimmune mechanisms, or to have important autoimmune components. The involved pathophysiological mechanisms and clinical manifestations have been better recognized and many of these disorders are potentially treatable by immunosuppression or by immunomodulation with intravenous immunoglobulin (IVIg. IVIg has been tried in a variety of immune-mediated neurological diseases, being target of widespread use in central and peripheral nervous systems diseases. Objective To give an overview of the main topics regarding the mechanism of action and different therapeutic uses of IVIg in neurological practice, mainly in neuromuscular diseases.

  3. Evaluation of neuromuscular activity in patients with obstructive sleep apnea using chin surface electromyography of polysomnography

    Institute of Scientific and Technical Information of China (English)

    YIN Guo-ping; YE Jing-ying; HAN De-min; WANG Xiao-yi; ZHANG Yu-huan; LI Yan-ru

    2013-01-01

    Background It is believed that defects in upper airway neuromuscular control play a role in sleep apnea pathogenesis.Currently,there is no simple and non-invasive method for evaluating neuromuscular activity for the purpose of screening in patients with obstructive sleep apnea.This study was designed to assess the validity of chin surface electromyography of routine polysomnography in evaluating the neuromuscular activity of obstructive sleep apnea subjects and probe the neuromuscular contribution in the pathogenesis of the condition.Methods The chin surface electromyography of routine polysomnography during normal breathing and obstructive apnea were quantified in 36 male patients with obstructive sleep apnea.The change of chin surface electromyography from normal breathing to obstructive apnea was expressed as the percent compensated electromyography value,where the percent compensated electromyography value =(normal breath surface electromyography-apnea surface electromyography)/normal breath surface electromyography,and the percent compensated electromyography values among subjects were compared.The relationship between sleep apnea related parameters and the percent compensated electromyography value was examined.Results The percent compensated electromyography value of the subjects varied from 1% to 90% and had a significant positive correlation with apnea hypopnea index (R2=0.382,P <0.001).Conclusions Recording and analyzing chin surface electromyography by routine polysomnography is a valid way of screening the neuromuscular activity in patients with obstructive sleep apnea.The neuromuscular contribution is different among subjects with obstructive sleep apnea.

  4. Defective membrane remodeling in neuromuscular diseases: insights from animal models.

    Directory of Open Access Journals (Sweden)

    Belinda S Cowling

    Full Text Available Proteins involved in membrane remodeling play an essential role in a plethora of cell functions including endocytosis and intracellular transport. Defects in several of them lead to human diseases. Myotubularins, amphiphysins, and dynamins are all proteins implicated in membrane trafficking and/or remodeling. Mutations in myotubularin, amphiphysin 2 (BIN1, and dynamin 2 lead to different forms of centronuclear myopathy, while mutations in myotubularin-related proteins cause Charcot-Marie-Tooth neuropathies. In addition to centronuclear myopathy, dynamin 2 is also mutated in a dominant form of Charcot-Marie-Tooth neuropathy. While several proteins from these different families are implicated in similar diseases, mutations in close homologues or in the same protein in the case of dynamin 2 lead to diseases affecting different tissues. This suggests (1 a common molecular pathway underlying these different neuromuscular diseases, and (2 tissue-specific regulation of these proteins. This review discusses the pathophysiology of the related neuromuscular diseases on the basis of animal models developed for proteins of the myotubularin, amphiphysin, and dynamin families. A better understanding of the common mechanisms between these neuromuscular disorders will lead to more specific health care and therapeutic approaches.

  5. Effects of shared medical appointments on quality of life and cost-effectiveness for patients with a chronic neuromuscular disease. Study protocol of a randomized controlled trial

    NARCIS (Netherlands)

    Seesing, F.M.; Drost, G.; Wilt, G.J. van der; Engelen, B.G.M. van

    2011-01-01

    BACKGROUND: Shared medical appointments are a series of one-to-one doctor-patient contacts, in presence of a group of 6-10 fellow patients. This group visits substitute the annual control visits of patients with the neurologist. The same items attended to in a one-to-one appointment are addressed. T

  6. Acute neuromuscular weakness associated with dengue infection

    OpenAIRE

    Harmanjit Singh Hira; Amandeep Kaur; Anuj Shukla

    2012-01-01

    Background: Dengue infections may present with neurological complications. Whether these are due to neuromuscular disease or electrolyte imbalance is unclear. Materials and Methods: Eighty-eight patients of dengue fever required hospitalization during epidemic in year 2010. Twelve of them presented with acute neuromuscular weakness. We enrolled them for study. Diagnosis of dengue infection based on clinical profile of patients, positive serum IgM ELISA, NS1 antigen, and sero-typing. Complete ...

  7. Cambios en el control neuromuscular de seis músculos de miembro inferior durante CMJ máximos realizados con fatiga

    Directory of Open Access Journals (Sweden)

    Gabriel Fábrica

    2013-06-01

    Full Text Available Hay diferentes opiniones respecto a si existen cambios en el control muscular cuando saltos con contramovimiento (CMJ son realizados en condición de fatiga. Este trabajo evalúa si la actividad y la secuencia temporal de activación de seis músculos de miembro inferior durante CMJ cambian por causa de la fatiga. El nivel de actividad varió principalmente en los músculos biarticulares. Los tiempos de los picos de actividad eléctrica sugieren la existencia de grupos de acción muscular, si bien ocurren cambios en la secuencia de activación dentro de cada grupo. Fue posible establecer que existe un patrón general de control muscular durante el apoyo en los CMJ, con ajustes del nivel y tiempo de activación que dependen del periodo temporal analizado y el músculo considerado.

  8. Mechanism and control of lake eutrophication

    Institute of Scientific and Technical Information of China (English)

    QIN Boqiang; YANG Liuyan; CHEN Feizhou; ZHU Guangwei; ZHANG Lu; CHEN Yiyu

    2006-01-01

    A review about lake naturally eutrophi- cating, the internal loading of nutrients from lake sediment as well as the mechanism of algal blooms and the control practices was made, especially the eutrophication problem of shallow lakes since sev- enty percent of fresh water lakes in China are shallow lakes. It was found that shallow lakes are apt toward eutrophication than deep lakes. Without any influ- ences of human activity, shallow lakes in the middle and lower reaches of Yangtze River are still easily eutrophicated, which may be owing to the effects of flood in this area. In shallow lakes, sediments are frequently disturbed by wind-wave and resuspended, which result in huge nutrients release to overlying water. This may be the major reason for higher in- ternal loading of nutrients in shallow lakes than in deep lakes. Algal bloom is an extreme response of lake ecosystem to the eutrophication. Appearance of algal blooms is related to physical condition of lakes, such as underwater radiation (or transparency), temperature, and hydrodynamic conditions, or related to geochemical conditions of lakes, like concentra- tions of nutrients and ratio of nitrogen to phosphorus, as well as the physiological advantage of cyanobac- teria such as vacuole for moving towards the radiant energy-rich zone and the mycosporine-like amino acids (MAAs) for resisting the harm of ultraviolet ra- diation. In shallow lakes, these advantages of cyanobacteria are favorable in the competition than in deep lakes. Also being the shallowness, it is more difficult to reduce nutrient loading and to control algae blooms in shallow lakes. For the control of eutrophi- cation, people should follow the sequence from pollution sources control, ecological restoration to catchment management. To control the internal nu- trient release, physical, chemical, biological tech- niques, and even bionic techniques could be selected. The idea of ecological restoration for a eutrophic lake is to shift the ecosystem

  9. PICU EXTUBATION FAILURE: THE ROLE OF NEUROMUSCULAR DISORDERS

    Directory of Open Access Journals (Sweden)

    N. Billan MD,

    2007-02-01

    Full Text Available ObjectiveNeuromuscular disorders (diseases of the motor unit, can cause respiratory problems such as impaired cough reflex, chest deformity, recurrent pneumonia and acute respiratory failure; these are the worst most common complications of these diseases and the leading cause of death in such patients (1, 2. Their management hence, very often, entails admission to the Pediatric Intensive Care Unit (PICU (3,4 and during this phase, endotracheal intubation is almost always necessary, to maintain the patency of airways and to apply Positive Pressure Ventilation (PPV. However, endotracheal intubation is always temporary, and its success or failure depends on the timely decision of its termination to restore the normal respiration or to avoid the risk of recurring respiratory failure (5, 6. We designed this study to evaluate the role of neuromuscular disorders in causing extubation failure as compared to that of other risk factors.Materials & MethodsIn an analytical cross-sectional study, the risk factors of reintubation and duration of mechanical ventilation in two groups of 30 patients each, was compared, the first successful extubation and the second with extubation failure.ResultsNeuromuscular disorders (including Spinal Muscular Atrophy, Guillain- Barre' Syndrome, Congenital Myopathies and Muscular Dystrophies were the main underlying diseases in extubation-failure group (P= 0.0002. Hypercapnia (PaCO2>50mmHg was shown to be the most common cause of both the first intubation (P=0.001 and reintubation (P=0.004 in the group of patients who failed extubation. The mean duration of intubation and mechanical ventilation was longer in patients with neuromuscular disorders who had extubation failure (P= 0.01.ConclusionThis study showed that, as underlying problems, neuromuscular disorders are the most common causes of prolonged intubation which defeat weaning from the ventilator and result in reintubation by inducing hypercapnia. Therefore the weaning

  10. Cambios en el control neuromuscular de seis músculos de miembro inferior durante CMJ máximos realizados con fatiga

    OpenAIRE

    Gabriel Fábrica; Paula González Rodríguez; Jefferson Fagundes Loss

    2013-01-01

    Hay diferentes opiniones respecto a si existen cambios en el control muscular cuando saltos con contramovimiento (CMJ) son realizados en condición de fatiga. Este trabajo evalúa si la actividad y la secuencia temporal de activación de seis músculos de miembro inferior durante CMJ cambian por causa de la fatiga. El nivel de actividad varió principalmente en los músculos biarticulares. Los tiempos de los picos de actividad eléctrica sugieren la existencia de grupos de acción muscular, si bien o...

  11. Assembly, plasticity and selective vulnerability to disease of mouse neuromuscular junctions.

    Science.gov (United States)

    Santos, Alexandre Ferrão; Caroni, Pico

    2003-01-01

    Although physiological differences among neuromuscular junctions (NMJs) have long been known, NMJs have usually been considered as one type of synapse, restricting their potential value as model systems to investigate mechanisms controlling synapse assembly and plasticity. Here we discuss recent evidence that skeletal muscles in the mouse can be subdivided into two previously unrecognized subtypes, designated FaSyn and DeSyn muscles. These muscles differ in the pattern of neuromuscular synaptogenesis during embryonic development. Differences between classes are intrinsic to the muscles, and manifest in the absence of innervation or agrin. The distinct rates of synaptogenesis in the periphery may influence processes of circuit maturation through retrograde signals. While NMJs on FaSyn and DeSyn muscles exhibit a comparable anatomical organization in postnatal mice, treatments that challenge synaptic stability result in nerve sprouting, NMJ remodeling, and ectopic synaptogenesis selectively on DeSyn muscles. This anatomical plasticity of NMJs diminishes greatly between 2 and 6 months postnatally. NMJs lacking this plasticity are lost selectively and very early on in mouse models of motoneuron disease, suggesting that disease-associated motoneuron dysfunction may fail to initiate maintenance processes at "non-plastic" NMJs. Transgenic mice overexpressing growth-promoting proteins in motoneurons exhibit greatly enhanced stimulus-induced sprouting restricted to DeSyn muscles, supporting the notion that anatomical plasticity at the NMJ is primarily controlled by processes in the postsynaptic muscle. The discovery that entire muscles in the mouse differ substantially in the anatomical plasticity of their synapses establishes NMJs as a uniquely advantageous experimental system to investigate mechanisms controlling synaptic rearrangements at defined synapses in vivo.

  12. Diagnostic Certified Assay: Neuromuscular and Cardiac Assessments

    Directory of Open Access Journals (Sweden)

    Rea Valaperta

    2013-01-01

    Full Text Available The expansion of the specific trinucleotide sequence, [CTG], is the molecular pathological mechanism responsible for the clinical manifestations of DM1. Many studies have described different molecular genetic techniques to detect DM1, but as yet there is no data on the analytical performances of techniques used so far in this disease. We therefore developed and validated a molecular method, “Myotonic Dystrophy SB kit,” to better characterize our DM1 population. 113 patients were examined: 20 DM1-positive, 11 DM1/DM2-negative, and13 DM1-negative/DM2-positive, who had a previous molecular diagnosis, while 69 were new cases. This assay correctly identified 113/113 patients, and all were confirmed by different homemade assays. Comparative analysis revealed that the sensitivity and the specificity of the new kit were very high (>99%. Same results were obtained using several extraction procedures and different concentrations of DNA. The distribution of pathologic alleles showed a prevalence of the “classical” form, while of the 96 nonexpanded alleles 19 different allelic types were observed. Cardiac and neuromuscular parameters were used to clinically characterize our patients and support the new genetic analysis. Our findings suggest that this assay appears to be a very robust and reliable molecular test, showing high reproducibility and giving an unambiguous interpretation of results.

  13. Urgencias en patología neuromuscular Emergencies in neuromuscular pathology

    Directory of Open Access Journals (Sweden)

    T. Ayuso

    2008-01-01

    . Within the broad group of neuromuscular diseases, those that most frequently provoke AMW and respiratory failure are Guillain-Barré syndrome (GBS and myasthenia gravis (MG. GBS is the most frequent cause of acute flaccid paralysis; it can cause respiratory failure in a third of cases, making mechanical ventilation necessary. Accurate diagnosis of this syndrome enables immunomodulatory treatment to be started, which has been shown to modify the course of the disease. Besides, clinical evaluation of the patients and knowledge of the simple tests of neurophysiology and respiratory function will guide the decision on mechanical ventilation, avoiding emergency intubation. The most frequent emergency caused by MG is myasthenic crisis, defined by the deterioration in the bulbar function with acute respiratory insufficiency and risk of respiratory stoppage. This occurs in 15-20% of myasthenic patients and can be triggered by numerous factors. Besides early identification of the crisis, it is important to suppress the triggering factors and to provide measure of ventilatory support. Amongst the pharmacological measures, the most useful instruments at present are plasmapheresis and intravenous immunoglobulins; these treatments do not cancel the need for intensive vigilance and of checking for imminent signs of respiratory failure that will involve invasive or non-invasive ventilatory support.

  14. Control mechanisms for a nonlinear model of international relations

    Energy Technology Data Exchange (ETDEWEB)

    Pentek, A.; Kadtke, J. [Univ. of California, San Diego, La Jolla, CA (United States). Inst. for Pure and Applied Physical Sciences; Lenhart, S. [Univ. of Tennessee, Knoxville, TN (United States). Mathematics Dept.; Protopopescu, V. [Oak Ridge National Lab., TN (United States). Computer Science and Mathematics Div.

    1997-07-15

    Some issues of control in complex dynamical systems are considered. The authors discuss two control mechanisms, namely: a short range, reactive control based on the chaos control idea and a long-term strategic control based on an optimal control algorithm. They apply these control ideas to simple examples in a discrete nonlinear model of a multi-nation arms race.

  15. Neuromuscular Adaptations to Reduced Use

    Science.gov (United States)

    Ploutz-Snyder, Lori

    2009-01-01

    This viewgraph presentation reviews the studies done to reduce neuromuscular strength loss during unilateral lower limb suspension (ULLS). Since there are animals that undergo fairly long periods of muscular disuse without any or minimal muscular atrophy, there is an answer to that might be applicable to human in situations that require no muscular use to diminish the effects of muscular atrophy. Three sets of ULLS studies were reviewed indicated that muscle strength decreased more than the muscle mass. The study reviewed exercise countermeasures to combat the atrophy, including: ischemia maintained during Compound muscle action potential (CMAP), ischemia and low load exercise, Japanese kaatsu, and the potential for rehabilitation or situations where heavy loading is undesirable. Two forms of countermeasures to unloading have been successful, (1) high-load resistance training has maintained muscle mass and strength, and low load resistance training with blood flow restriction (LL(sub BFR)). The LL(sub BFR) has been shown to increase muscle mass and strength. There has been significant interest in Tourniquet training. An increase in Growth Hormone(GH) has been noted for LL(sub BFR) exercise. An experimental study with 16 subjects 8 of whom performed ULLS, and 8 of whom performed ULLS and LL(sub BFR) exercise three times per week during the ULLS. Charts show the results of the two groups, showing that performing LL(sub BFR) exercise during 30 days of ULLS can maintain muscle size and strength and even improve muscular endurance.

  16. Cellular Mechanisms of Ciliary Length Control

    Directory of Open Access Journals (Sweden)

    Jacob Keeling

    2016-01-01

    Full Text Available Cilia and flagella are evolutionarily conserved, membrane-bound, microtubule-based organelles on the surface of most eukaryotic cells. They play important roles in coordinating a variety of signaling pathways during growth, development, cell mobility, and tissue homeostasis. Defects in ciliary structure or function are associated with multiple human disorders called ciliopathies. These diseases affect diverse tissues, including, but not limited to the eyes, kidneys, brain, and lungs. Many processes must be coordinated simultaneously in order to initiate ciliogenesis. These include cell cycle, vesicular trafficking, and axonemal extension. Centrioles play a central role in both cell cycle progression and ciliogenesis, making the transition between basal bodies and mitotic spindle organizers integral to both processes. The maturation of centrioles involves a functional shift from cell division toward cilium nucleation which takes place concurrently with its migration and fusion to the plasma membrane. Several proteinaceous structures of the distal appendages in mother centrioles are required for this docking process. Ciliary assembly and maintenance requires a precise balance between two indispensable processes; so called assembly and disassembly. The interplay between them determines the length of the resulting cilia. These processes require a highly conserved transport system to provide the necessary substances at the tips of the cilia and to recycle ciliary turnover products to the base using a based microtubule intraflagellar transport (IFT system. In this review; we discuss the stages of ciliogenesis as well as mechanisms controlling the lengths of assembled cilia.

  17. Effect of early progressive exercises on neuromuscular function recovery of mechanically ventilated patients in intensive care unit%早期渐进性活动训练促进重症监护病房机械通气患者神经肌肉功能恢复的效果观察

    Institute of Scientific and Technical Information of China (English)

    胡细玲; 陈妙霞; 凌聪; 蔡有弟; 郭晓迪

    2012-01-01

    目的 探讨早期渐进性活动训练促进重症监护病房(intensive care unit,ICU)机械通气患者神经肌肉功能恢复的效果.方法 将98例ICU机械通气患者随机分为实验组和对照组,每组各49例,实验组患者在镇静中断后每天实施两次早期渐进性活动训练;对照组患者每天两次接受床上被动或主动全范围关节活动.采用功能独立性评分表(functional independence measure,FIM)对两组患者分别在拔除气管插管时、转出ICU时和出院时进行评定,并比较两组患者住院期间并发症发生情况.结果 实验组患者在拔除气管插管时FIM总分及自理能力、括约肌控制、转移方面得分明显高于对照组,两组比较,均P<0.05,差异具有统计学意义;实验组患者在转出ICU时和出院时在FIM总分及5个方面得分明显高于对照组,两组比较,均P<0.05,差异具有统计学意义.实验组患者呼吸机相关性肺炎(ventilator associated pneumonia,VAP)、下肢深静脉栓塞(deep vein thrombosis,DVT)的发生率明显低于对照组,两组比较,均P<0.05,差异具有统计学意义.结论 早期渐进性活动训练能促进ICU机械通气患者神经肌肉功能恢复,并可降低相关并发症的发生率.%Objective To study the effect of early progressive exercises on neuromuscular function recovery of mechanically ventilated patients in intensive care unit. Methods 98 mechanically ventilated patients in the ICU were randomly divided into the experiment group and the control group, 49 patients in each group. Patients in the experiment group were implemented the training program of early progressive exercise twice a day once the sedation was cut off. Patients in the control group were implemented early passive or active training of joint activities in a full range on bed twice a day. The two groups were assessed in terms of complications using the Functional Independence Measures at the time of extubation, shifting out of ICU

  18. Adaptive mechanically controlled lubrication mechanism found in articular joints.

    Science.gov (United States)

    Greene, George W; Banquy, Xavier; Lee, Dong Woog; Lowrey, Daniel D; Yu, Jing; Israelachvili, Jacob N

    2011-03-29

    Articular cartilage is a highly efficacious water-based tribological system that is optimized to provide low friction and wear protection at both low and high loads (pressures) and sliding velocities that must last over a lifetime. Although many different lubrication mechanisms have been proposed, it is becoming increasingly apparent that the tribological performance of cartilage cannot be attributed to a single mechanism acting alone but on the synergistic action of multiple "modes" of lubrication that are adapted to provide optimum lubrication as the normal loads, shear stresses, and rates change. Hyaluronic acid (HA) is abundant in cartilage and synovial fluid and widely thought to play a principal role in joint lubrication although this role remains unclear. HA is also known to complex readily with the glycoprotein lubricin (LUB) to form a cross-linked network that has also been shown to be critical to the wear prevention mechanism of joints. Friction experiments on porcine cartilage using the surface forces apparatus, and enzymatic digestion, reveal an "adaptive" role for an HA-LUB complex whereby, under compression, nominally free HA diffusing out of the cartilage becomes mechanically, i.e., physically, trapped at the interface by the increasingly constricted collagen pore network. The mechanically trapped HA-LUB complex now acts as an effective (chemically bound) "boundary lubricant"--reducing the friction force slightly but, more importantly, eliminating wear damage to the rubbing/shearing surfaces. This paper focuses on the contribution of HA in cartilage lubrication; however, the system as a whole requires both HA and LUB to function optimally under all conditions.

  19. Control Mechanism and Security Region for Intentional Islanding Transition

    DEFF Research Database (Denmark)

    Chen, Yu; Xu, Zhao; Østergaard, Jacob

    2009-01-01

    in the grid. The concept of Islanding Security Region (ISR) has been proposed as an organic composition of the developed control mechanism. The purpose of this control mechanism is to maintain the frequency stability and eventually the security of power supply to the customers, by utilizing resources from...... generation and demand sides. The control mechanism can be extended to consider the distributed generations like wind power and other innovative technologies such as the Demand as Frequency controlled Reserve (DFR) technique in the future....

  20. Effects of neuromuscular electrostimulation in patients with heart failure admitted to ward

    Directory of Open Access Journals (Sweden)

    de Araújo Carlos José Soares

    2012-11-01

    Full Text Available Abstract Background Neuromuscular electrostimulation has become a promising issue in cardiovascular rehabilitation. However there are few articles published in the literature regarding neuromuscular electrostimulation in patients with heart failure during hospital stay. Methods This is a randomized controlled pilot trial that aimed to investigate the effect of neuromuscular electrostimulation in the walked distance by the six-minute walking test in 30 patients admitted to ward for heart failure treatment in a tertiary cardiology hospital. Patients in the intervention group performed a conventional rehabilitation and neuromuscular electrostimulation. Patients underwent 60 minutes of electrostimulation (wave frequency was 20 Hz, pulse duration of 20 us two times a day for consecutive days until hospital discharge. Results The walked distance in the six-minute walking test improved 75% in the electrostimulation group (from 379.7 ± 43.5 to 372.9 ± 46.9 meters to controls and from 372.9 ± 62.4 to 500 ± 68 meters to electrostimulation, p Conclusion The neuromuscular electrostimulation group showed greater improvement in the walked distance in the six-minute walking test in patients admitted to ward for compensation of heart failure.

  1. Controlled Unusual Stiffness of Mechanical Metamaterials.

    Science.gov (United States)

    Lee, Wooju; Kang, Da-Young; Song, Jihwan; Moon, Jun Hyuk; Kim, Dongchoul

    2016-02-03

    Mechanical metamaterials that are engineered with sub-unit structures present unusual mechanical properties depending on the loading direction. Although they show promise, their practical utility has so far been somewhat limited because, to the best of our knowledge, no study about the potential of mechanical metamaterials made from sophisticatedly tailored sub-unit structures has been made. Here, we present a mechanical metamaterial whose mechanical properties can be systematically designed without changing its chemical composition or weight. We study the mechanical properties of triply periodic bicontinuous structures whose detailed sub-unit structure can be precisely fabricated using various sub-micron fabrication methods. Simulation results show that the effective wave velocity of the structures along with different directions can be designed to introduce the anisotropy of stiffness by changing a volume fraction and aspect ratio. The ratio of Young's modulus to shear modulus can be increased by up to at least 100, which is a 3500% increase over that of isotropic material (2.8, acrylonitrile butadiene styrene). Furthermore, Poisson's ratio of the constituent material changes the ratio while Young's modulus does not influence it. This study presents the promising potential of mechanical metamaterials for versatile industrial and biomedical applications.

  2. Research highlights of partial neuromuscular disorders

    Directory of Open Access Journals (Sweden)

    Cheng ZHANG

    2014-05-01

    Full Text Available In order to understand the latest progression on neuromuscular disorders for clinicians, this review screened and systemized the papers on neuromuscular disorders which were collected by PubMed from January 2013 to February 2014. This review also introduced the clinical diagnosis and treatment hightlights on glycogen storage disease type Ⅱ (GSD Ⅱ, Duchenne muscular dystrophy (DMD, amyotrophic lateral sclerosis (ALS and spinal muscular atrophy (SMA. The important references will be useful for clinicians. doi: 10.3969/j.issn.1672-6731.2014.05.004

  3. Neuromuscular action of crotalid venom: preliminar data

    OpenAIRE

    Maria Dorvalina Silva; Luiz Antônio L. Resende; Anete Kimuni Ueda; Benedito Barraviera; Mendes, R P; Montenegro, Mário Rubens G. [UNESP

    1996-01-01

    Estudamos 6 pacientes, 2 cães e um coelho com intoxicação crotálica. Avaliamos a condução nervosa periférica sensitiva e motora, a transmissão neuromuscular e eletromiografias. As biópsias de músculo foram processadas por histoquímica. Os 6 pacientes apresentaram mononeuropatia sensitiva no nervo periférico adjacente ao local da inoculação do veneno e encontramos evidências histoquímicas de miopatia mitocondrial. Os defeitos da transmissão neuromuscular foram mínimos. A maioria dos autores ad...

  4. 21 CFR 882.5860 - Implanted neuromuscular stimulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted neuromuscular stimulator. 882.5860... (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5860 Implanted neuromuscular stimulator. (a) Identification. An implanted neuromuscular stimulator is a device that...

  5. Finite-time Control of One-link Mechanical System

    Science.gov (United States)

    Matoba, Shunsuke; Nakamura, Nami; Nakamura, Hisakazu; Akiba, Hideyuki

    This paper considers finite-time position control of an one-link mechanical system. The system is modeled by discontinuous differential equations. In this paper, we prove that the Nakamura's local homogeneous controller based on a control Lyapunov function is valid to the position control of the robot manipulators, and show the effectiveness of the controller by experiments.

  6. The effect of timing electrical stimulation to robotic-assisted stepping on neuromuscular activity and associated kinematics

    OpenAIRE

    Sina Askari, MS; TeKang Chao; Ray D. de Leon, PhD; Deborah S. Won, PhD

    2013-01-01

    Results of previous studies raise the question of how timing neuromuscular functional electrical stimulation (FES) to limb movements during stepping might alter neuromuscular control differently than patterned stimulation alone. We have developed a prototype FES system for a rodent model of spinal cord injury (SCI) that times FES to robotic treadmill training (RTT). In this study, one group of rats (n = 6) was trained with our FES+RTT system and received stimulation of the ankle flexor (tibia...

  7. Correction of organophosphate-induced neuromuscular blockade by diphenhydramine.

    Science.gov (United States)

    Clemmons, R M; Meyer, D J; Sundlof, S F; Rappaport, J J; Fossler, M E; Hubbell, J; Dorsey-Lee, M R

    1984-10-01

    Dogs exposed to topical organophosphate (fenthion) developed decreased plasma and muscle cholinesterase activities. After 2 doses were applied (1 week between doses), plasma concentrations declined 80% and muscle cholinesterase activity was reduced by 56%. Decremental responses to repetitive nerve stimulation developed after fenthion administration. Diphenhydramine, but not placebo, corrected the electrical abnormalities caused by organophosphate application, but without altering plasma or muscle cholinesterase activity. Control dogs housed in the same kennel demonstrated a slight decrease (18%) of plasma cholinesterase, which indicates that there may be potential cross contamination. Diphenydramine may be effective in treating organophosphate-induced neuromuscular weakness which is refractory to other forms of therapy.

  8. Naturally occurring plant polyphenols as potential therapies for inherited neuromuscular diseases.

    Science.gov (United States)

    Fuller, Heidi R; Humphrey, Emma L; Morris, Glenn E

    2013-11-01

    There are several lines of laboratory-based evidence emerging to suggest that purified polyphenol compounds such as resveratrol, found naturally in red grapes, epigallocatechin galate from green tea and curcumin from turmeric, might be useful for the treatment of various inherited neuromuscular diseases, including spinal muscular atrophy, Duchenne muscular dystrophy and Charcot-Marie-Tooth disease. Here, we critically examine the scientific evidence related to the known molecular effects that these polyphenols have on different models of inherited neuromuscular disease, with particular attention to problems with the validity of in vitro evidence. We also present proteomic evidence that polyphenols have in vitro effects on cells related to metal ion chelation in cell-culture media. Although their precise mechanisms of action remain somewhat elusive, polyphenols could be an attractive approach to therapy for inherited neuromuscular disease, especially since they may be safer to use on young children, compared with some of the other drug candidates.

  9. Analysis and control of underactuated mechanical systems

    CERN Document Server

    Choukchou-Braham, Amal; Djemaï, Mohamed; Busawon, Krishna

    2014-01-01

    This monograph provides readers with tools for the analysis, and control of systems with fewer control inputs than degrees of freedom to be controlled, i.e., underactuated systems. The text deals with the consequences of a lack of a general theory that would allow methodical treatment of such systems and the ad hoc approach to control design that often results, imposing a level of organization whenever the latter is lacking. The authors take as their starting point the construction of a graphical characterization or control flow diagram reflecting the transmission of generalized forces through the degrees of freedom. Underactuated systems are classified according to the three main structures by which this is found to happen—chain, tree, and isolated vertex—and control design procedures proposed. The procedure is applied to several well-known examples of underactuated systems: acrobot; pendubot; Tora system; ball and beam; inertia wheel; and robotic arm with elastic joint. The text is illustrated with MATL...

  10. Towards a Unified Representation of Mechanisms for Robotic Control Software

    Directory of Open Access Journals (Sweden)

    Antonio Diaz-Calderon

    2008-11-01

    Full Text Available This article gives an overview of the Mechanism Model paradigm. The mechanism model paradigm provides a framework to modeling mechanisms for robotic control. The emphasis is on the unification of mathematical models of kinematics/dynamics, geometric information and control system parameters for a variety of robotic systems (including serial manipulators, wheeled and legged locomotors, with algorithms that are needed for typical robot control applications.

  11. Comparison of mechanomyography and acceleromyography for the assessment of rocuronium induced neuromuscular block in myotonic dystrophy type 1.

    Science.gov (United States)

    Vanlinthout, L E H; Booij, L H D J; van Egmond, J; Robertson, E N

    2010-06-01

    We measured acceleromyography and mechanomyography simultaneously with monitoring of rocuronium-induced neuromuscular block in four patients with myotonic dystrophy type 1. Furthermore, we compared neuromuscular block measures from these patients with those from normal controls from previous studies. In myotonic dystrophy type 1 patients, the dose-response curve obtained with acceleromyography was steeper and right-shifted compared with that obtained using mechanomyography. However, the effective doses to produce 95% neuromuscular block determined with both acceleromyography and mechanomyography were similar to each other and to values found in normal patients. In the three myotonic dystrophy type 1 patients with mild to moderate disease, times to recovery from block were similar to those observed in normal controls. In both patients and normal controls, neuromuscular block recovered faster with acceleromyography. However, in one patient with severe muscle wasting, recovery of neuromuscular block was prolonged. We conclude that mechanomyography and acceleromyography cannot be used interchangeably to monitor neuromuscular block in myotonic dystrophy type 1 patients.

  12. Postoperative effects of neuromuscular exercise prior to hip or knee arthroplasty

    DEFF Research Database (Denmark)

    Villadsen, Allan; Overgaard, Søren; Holsgaard-Larsen, Anders

    2014-01-01

    neuromuscular exercise prior to total joint arthroplasty (TJA) of the hip or knee did not confer additional benefits 3 months postoperatively compared with TJA alone. However, the intervention group experienced a statistically significant short-term benefit in ADL and pain, suggesting an earlier onset......OBJECTIVE: To investigate the postoperative efficacy of a supervised programme of neuromuscular exercise prior to hip or knee arthroplasty. METHODS: In this assessor-blinded randomised controlled trial, we included 165 patients scheduled for hip or knee arthroplasty due to severe osteoarthritis (OA......). An 8-week preoperative neuromuscular supervised exercise programme was delivered twice a week for 1 h as adjunct treatment to the standard arthroplasty procedure and compared with the standard arthroplasty procedure alone. The primary outcome was self-reported physical function measured...

  13. Cutaneous mechanisms of isometric ankle force control

    DEFF Research Database (Denmark)

    Choi, Julia T; Jensen, Jesper Lundbye; Leukel, Christian

    2013-01-01

    The sense of force is critical in the control of movement and posture. Multiple factors influence our perception of exerted force, including inputs from cutaneous afferents, muscle afferents and central commands. Here, we studied the influence of cutaneous feedback on the control of ankle force...... of transient stimulation on force error were greater when compared to continuous stimulation and lidocaine injection. Position-matching performance was unaffected by peroneal nerve or plantar nerve stimulation. Our results show that cutaneous feedback plays a role in the control of force output at the ankle...... joint. Understanding how the nervous system normally uses cutaneous feedback in motor control will help us identify which functional aspects are impaired in aging and neurological diseases....

  14. Control Engineering Analysis of Mechanical Pitch Systems

    Science.gov (United States)

    Bernicke, Olaf; Gauterin, Eckhard; Schulte, Horst; Zajac, Michal

    2014-12-01

    With the help of a local stability analysis the coefficient range of a discrete damper, used for centrifugal forced, mechanical pitch system of small wind turbines (SWT), is gained for equilibrium points. - By a global stability analysis the gained coefficient range can be validated. An appropriate approach by Takagi-Sugeno is presented in the paper.

  15. Prevalence of complications in neuromuscular scoliosis surgery

    DEFF Research Database (Denmark)

    Sharma, Shallu; Wu, Chunsen; Andersen, Thomas;

    2013-01-01

    PURPOSE: Our objectives were primarily to review the published literature on complications in neuromuscular scoliosis (NMS) surgery and secondarily, by means of a meta-analysis, to determine the overall pooled rates (PR) of various complications associated with NMS surgery. METHODS: PubMed and Em...

  16. Neuromuscular Effects of Acute Organophosphate Poisoning

    Directory of Open Access Journals (Sweden)

    Taylan Pekoz

    2014-08-01

    Conclusion: There is no evoked potential studies performed in organophosphate poisoning althoung electroneurography repetitive and P300 studies exist in literature. More further studies are needed to evaluate the cardiac and neuromuscular effects of organophosphate poisoning. [Cukurova Med J 2014; 39(4.000: 795-800

  17. CLINICAL PHARMACOKINETICS OF NEUROMUSCULAR BLOCKING-DRUGS

    NARCIS (Netherlands)

    AGOSTON, S; VANDENBROM, RHG; WIERDA, JMKH

    1992-01-01

    Neuromuscular blocking agents provide muscle relaxation for a great variety of surgical procedures with light planes of general anaesthesia. Besides having a significant impact in the development of anaesthesia and surgery, these agents continue to play an important role as pharmacological tools in

  18. [Visual attention and its control mechanisms].

    Science.gov (United States)

    Ogawa, Hirokazu

    2014-04-01

    Given the vast amount of visual information in visual scenes, the capacity of our brain to processes such scenes is severely limited. The core mechanism of selection is referred to as visual attention, and it has been the topic of intense investigation for over 25 years in experimental psychology and cognitive neuroscience. Visual attention is not a single, unitary mechanism, but consists of multiple subcomponents. Attention can be directed to various aspects of visual information, such as spatial location, features, or objects. Additionally, attention is guided by external factors such as the salience of stimuli, or whether we are able to move our attention volitionally. The purpose of this article is to review the status of these components of attentional guidance and how they interact with each other, with an emphasis on psychophysical studies.

  19. O uso de bloqueadores neuromusculares no Brasil El uso de bloqueadores neuromusculares en Brasil Neuromuscular blockers in Brazil

    Directory of Open Access Journals (Sweden)

    Maria Cristina Simões de Almeida

    2004-12-01

    Full Text Available JUSTIFICATIVA E OBJETIVOS: Dados estatísticos referentes ao uso de bloqueadores neuromusculares no Brasil são desconhecidos. Este trabalho se propõe a análise estatística desse tópico. MÉTODO: Foram compiladas 831 respostas de um questionário preenchido em parte por anestesiologistas presentes ao 48º Congresso Brasileiro de Anestesiologia em Recife, 2001 e em parte via Internet, por anestesiologistas cujos endereços eletrônicos constam na página da Sociedade Brasileira de Anestesiologia (www.sba.com.br. Foram analisados os seguintes dados: tempo de contato com a especialidade, região onde atuam os anestesiologistas, uso de bloqueadores neuromusculares (BNM em ordem de preferência, indicações do uso de succinilcolina, uso do monitor da transmissão neuromuscular, critérios para se considerar o paciente descurarizado, uso de neostigmina, forma de administração dos BNM e descrição de complicações observadas. RESULTADOS: A maioria dos anestesiologistas em questão exerce a profissão há mais de 11 anos e o maior número de respostas foi proveniente da região sudeste do Brasil. O BNM mais empregado é o atracúrio, seguido de pancurônio e succinilcolina. A succinilcolina é mais empregada na indução rápida e em crianças (80% e 25% respectivamente. Monitores da transmissão neuromuscular, 53% dos anestesiologistas nunca usam, e como critério de recuperação, 92% consideram o paciente descurarizado mediante sinais clínicos. Em 45% das vezes os profissionais empregam a neostigmina de forma rotineira, e 94% administra os BNM sob forma de bolus. Cerca de 30% registra ter havido complicação decorrente do uso de BNM. As complicações mais apontadas foram o bloqueio prolongado, o broncoespasmo grave e a curarização residual. CONCLUSÕES: O atracúrio é o bloqueador neuromuscular mais empregado no Brasil, há percentual alto de uso da succinilcolina em situações não emergenciais, o uso de monitores da transmiss

  20. High Precision Motion Control of Hybrid Five-Bar Mechanism with an Intelligent Control

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ke; WANG Sheng-ze

    2009-01-01

    Hybrid mechanism is a new type of planar controllable mechanism. Position control accuracy of system determines the output acctracy of the mechanism In order to achieve the desired high accuracy, nonlinear factors as friction must be accurately compensated in the real-time servo control algarithm. In this paper, the model of a hybrid flve-bar mechanism is introduced In terms of the characteristics of the hybrid mechanism, a hybrid intelligent control algorithm based on proportional-integral-derivative(PID) control and cerebellar model articulation control techniques was presented and used to perform control of hybrid five-bar mechanism for the first time. The simulation results show that the hybrid control method can improve the control effect remarkably, compared with the traditional PID control strategy.

  1. Cutaneous mechanisms of isometric ankle force control.

    Science.gov (United States)

    Choi, Julia T; Lundbye-Jensen, Jesper; Leukel, Christian; Nielsen, Jens Bo

    2013-07-01

    The sense of force is critical in the control of movement and posture. Multiple factors influence our perception of exerted force, including inputs from cutaneous afferents, muscle afferents and central commands. Here, we studied the influence of cutaneous feedback on the control of ankle force output. We used repetitive electrical stimulation of the superficial peroneal (foot dorsum) and medial plantar nerves (foot sole) to disrupt cutaneous afferent input in 8 healthy subjects. We measured the effects of repetitive nerve stimulation on (1) tactile thresholds, (2) performance in an ankle force-matching and (3) an ankle position-matching task. Additional force-matching experiments were done to compare the effects of transient versus continuous stimulation in 6 subjects and to determine the effects of foot anesthesia using lidocaine in another 6 subjects. The results showed that stimulation decreased cutaneous sensory function as evidenced by increased touch threshold. Absolute dorsiflexion force error increased without visual feedback during peroneal nerve stimulation. This was not a general effect of stimulation because force error did not increase during plantar nerve stimulation. The effects of transient stimulation on force error were greater when compared to continuous stimulation and lidocaine injection. Position-matching performance was unaffected by peroneal nerve or plantar nerve stimulation. Our results show that cutaneous feedback plays a role in the control of force output at the ankle joint. Understanding how the nervous system normally uses cutaneous feedback in motor control will help us identify which functional aspects are impaired in aging and neurological diseases.

  2. Dynamics and control of a class of underactuated mechanical systems

    NARCIS (Netherlands)

    Reyhanoglu, Mahmut; Schaft, van der Arjan; McClamroch, N. Harris; Kolmanovsky, Ilya

    1999-01-01

    This paper presents a theoretical framework for the dynamics and control of underactuated mechanical systems, defined as systems with fewer inputs than degrees of freedom. Control system formulation of underactuated mechanical systems is addressed and a class of underactuated systems characterized b

  3. Dynamics and Control of a Class of Underactuated Mechanical Systems

    NARCIS (Netherlands)

    Reyhanoglu, Mahmut; Schaft, Arjan van der; McClamroch, N. Harris; Kolmanovsky, Ilya

    1999-01-01

    This paper presents a theoretical framework for the dynamics and control of underactuated mechanical systems, defined as systems with fewer inputs than degrees of freedom. Control system formulation of underactuated mechanical systems is addressed and a class of underactuated systems characterized b

  4. Improving Control Mechanism at Routers in TCP/IP Network

    Directory of Open Access Journals (Sweden)

    Nguyen Kim Quoc

    2014-09-01

    Full Text Available The existing control mechanisms at the network nodes have a good active and very effective at each local router, but they do not still strong enough to control nonlinear and dynamical behaviour of the network. Therefore, the control system requirements must be designed to be flexible to fully grasp the important status information of the variation and intelligent control methods to control network congestion in nonlinear network. To solve this problem, we propose a solution combined fuzzy reasoning with neural network control put on active queue management mechanisms at the network nodes.

  5. Mirror Visual Feedback Induces Lower Neuromuscular Activity in Children with Spastic Hemiparetic Cerebral Palsy

    Science.gov (United States)

    Feltham, Max G.; Ledebt, Annick; Deconinck, Frederik J. A.; Savelsbergh, Geert J. P.

    2010-01-01

    The study examined the effects of mirror feedback information on neuromuscular activation during bimanual coordination in eight children with spastic hemiparetic cerebral palsy (SHCP) and a matched control group. The "mirror box" creates a visual illusion, which gives rise to a visual perception of a zero lag, symmetric movement between the two…

  6. Effect of exercise therapy on neuromuscular activity and knee strength in female adolescents with patellofemoral pain

    DEFF Research Database (Denmark)

    Rathleff, Michael S.; Samani, Afshin; Olesen, Jens L.;

    2016-01-01

    . A random subsample of 57 female adolescents was included and tested at baseline and after 3months. Neuromuscular control of the knee was quantified as the complexity of surface electromyography of the vastus lateralis and vastus medialis during stair descent. Secondary outcomes were complexity of knee...

  7. Electromyographic and Neuromuscular Force Patterns Associated with Unexpectedly Loaded Rapid Limb Movements.

    Science.gov (United States)

    Richardson, Charles; Simmons, Roger W.

    Bi-articular, unidirectional arm movements were studied to evaluate the electromyographic (EMG) and neuromuscular force patterns that occur when a limb is unexpectedly perturbed. A series of training trials were continued with a control load spring attached to the apparatus until a pre-specified criterion for learning was attained. The limb was…

  8. Family Stress with Chronic Childhood Illness: Cystic Fibrosis, Neuromuscular Disease, and Renal Disease.

    Science.gov (United States)

    Holroyd, Jean; Guthrie, Donald

    1986-01-01

    Parents of children with neuromuscular disease, cystic fibrosis, and renal disease were compared with parents of control subjects matched by age to the clinical cases. The three clinical groups exhibited different patterns of stressful response, consistent with the nature of their illnesses and the requirements for care imposed on the families.…

  9. Neuromuscular Adaptations to Eccentric Strength Training in Children and Adolescents with Cerebral Palsy

    Science.gov (United States)

    Reid, Siobhan; Hamer, Peter; Alderson, Jacqueline; Lloyd, David

    2010-01-01

    Aim: To determine the neuromuscular outcomes of an eccentric strength-training programme for children and adolescents with cerebral palsy (CP). Method: In this randomised, parallel-group trial with waiting control, 14 participants with CP (six males, eight females; mean age 11y, SD 2y range 9-15y), diagnosed with upper-limb spasticity were…

  10. Effects of intensive physical rehabilitation on neuromuscular adaptations in adults with poststroke hemiparesis

    DEFF Research Database (Denmark)

    Andersen, Lars L; Zeeman, Peter; Jørgensen, Jørgen R

    2011-01-01

    the effect of intensive physical rehabilitation on neuromuscular and functional adaptations in outpatients suffering from hemiparesis after stroke. A within-subject repeated-measures design with the paretic leg as the experimental leg and the nonparetic leg as the control leg was used. Eleven outpatients...

  11. Comparison between two different neuromuscular electrical stimulation protocols for the treatment of female stress urinary incontinence: a randomized controlled trial Comparação de diferentes procedimentos de estimulação elétrica neuromuscular utilizados no tratamento da incontinência urinária de esforço feminina: ensaio clínico randomizado

    Directory of Open Access Journals (Sweden)

    Priscila G. J. M. Alves

    2011-10-01

    Full Text Available BACKGROUND: Neuromuscular electrical stimulation (NMES is widely treatment for stress urinary incontinence (SUI but there is no consensus in literature regarding the most effective treatment parameters. OBJECTIVE: To compare two NMESintra-vaginal protocols for the treatment of SUI in women. METHODS: The study included 20 volunteers with an average age of 55.55±6.51 years and with the clinical diagnosis of SUI. Volunteers were randomly divided into two groups: group 1 (G1 received NMES with medium-frequency current and group 2 (G2 received NMES with low-frequency current. Functional assessments of pelvic floor muscles (PFM were performed by perineometry. The severity of signs and symptoms were objectively evaluated using the 1 hour pad test and subjectively evaluated using a visual analog scale that measured the discomfort caused by the SUI. Shapiro-Wilk test was used to analyze data normality, and the Friedman test was used to analyze nonparametric data. For analysis of symptoms related to SUI the Fisher exact test and the Mann-Whitney test were used. Significance level of 5% was set for all data analysis. RESULTS: No significant differences (p>0.05 were found between groups for any of the variable assessed. The within group analysis of initial and final evaluations (after NMES demonstrated significant differences (pCONTEXTUALIZAÇÃO: A estimulação elétrica neuromuscular (EENM é amplamente utilizada no tratamento da incontinência urinária de esforço (IUE, no entanto não há consenso na literatura sobre os parâmetros de tratamento mais eficazes. OBJETIVO: Avaliar os procedimentos de EENM intravaginal no tratamento de mulheres com IUE. MÉTODOS: Participaram do estudo 20 voluntárias com idade média de 55,55±6,51 anos, com diagnóstico clínico de IUE. As voluntárias foram divididas aleatoriamente em dois grupos: grupo 1 (G1, que recebeu EENM com corrente de média frequência, e grupo 2 (G2, com corrente de baixa frequência. A

  12. Novel Mechanism Control Algorithm for Wired Network

    Directory of Open Access Journals (Sweden)

    V. B. Kirubanand

    2011-01-01

    Full Text Available Problem statement: A critical issue in wireless network where the data can hack by the person and we add a novel encryption mechanism to protect the data transfer from client to server and vice versa. Approach: We present a queuing model of a client and server that uses for bulk arrival service. The arrival of data requests is assumed to Markov Poisson Distributed Process (MPDP and the events are considered in the server for process sharing. We obtained the parameter of service rate, arrival rate, expected waiting time and expected busy period. We also derive the expression for the data value of threshold. Results: The total number of packets request processed, there was no time limit to arrivals, while compared to m/m/1 model. Our model m/m (1,b/1 was more efficient to find response and request time in between client and server. Conclusions: Our proposed simulation model validated through Java programming.

  13. An immunosurveillance mechanism controls cancer cell ploidy.

    Science.gov (United States)

    Senovilla, Laura; Vitale, Ilio; Martins, Isabelle; Tailler, Maximilien; Pailleret, Claire; Michaud, Mickaël; Galluzzi, Lorenzo; Adjemian, Sandy; Kepp, Oliver; Niso-Santano, Mireia; Shen, Shensi; Mariño, Guillermo; Criollo, Alfredo; Boilève, Alice; Job, Bastien; Ladoire, Sylvain; Ghiringhelli, François; Sistigu, Antonella; Yamazaki, Takahiro; Rello-Varona, Santiago; Locher, Clara; Poirier-Colame, Vichnou; Talbot, Monique; Valent, Alexander; Berardinelli, Francesco; Antoccia, Antonio; Ciccosanti, Fabiola; Fimia, Gian Maria; Piacentini, Mauro; Fueyo, Antonio; Messina, Nicole L; Li, Ming; Chan, Christopher J; Sigl, Verena; Pourcher, Guillaume; Ruckenstuhl, Christoph; Carmona-Gutierrez, Didac; Lazar, Vladimir; Penninger, Josef M; Madeo, Frank; López-Otín, Carlos; Smyth, Mark J; Zitvogel, Laurence; Castedo, Maria; Kroemer, Guido

    2012-09-28

    Cancer cells accommodate multiple genetic and epigenetic alterations that initially activate intrinsic (cell-autonomous) and extrinsic (immune-mediated) oncosuppressive mechanisms. Only once these barriers to oncogenesis have been overcome can malignant growth proceed unrestrained. Tetraploidization can contribute to oncogenesis because hyperploid cells are genomically unstable. We report that hyperploid cancer cells become immunogenic because of a constitutive endoplasmic reticulum stress response resulting in the aberrant cell surface exposure of calreticulin. Hyperploid, calreticulin-exposing cancer cells readily proliferated in immunodeficient mice and conserved their increased DNA content. In contrast, hyperploid cells injected into immunocompetent mice generated tumors only after a delay, and such tumors exhibited reduced DNA content, endoplasmic reticulum stress, and calreticulin exposure. Our results unveil an immunosurveillance system that imposes immunoselection against hyperploidy in carcinogen- and oncogene-induced cancers.

  14. Stathmin is required for stability of the Drosophila neuromuscular junction.

    Science.gov (United States)

    Graf, Ethan R; Heerssen, Heather M; Wright, Christina M; Davis, Graeme W; DiAntonio, Aaron

    2011-10-19

    Synaptic connections can be stably maintained for prolonged periods, yet can be rapidly disassembled during the developmental refinement of neural circuitry and following cytological insults that lead to neurodegeneration. To date, the molecular mechanisms that determine whether a synapse will persist versus being remodeled or eliminated remain poorly understood. Mutations in Drosophila stathmin were isolated in two independent genetic screens that sought mutations leading to impaired synapse stability at the Drosophila neuromuscular junction (NMJ). Here we demonstrate that Stathmin, a protein that associates with microtubules and can function as a point of signaling integration, is necessary to maintain the stability of the Drosophila NMJ. We show that Stathmin protein is widely distributed within motoneurons and that loss of Stathmin causes impaired NMJ growth and stability. In addition, we show that stathmin mutants display evidence of defective axonal transport, a common feature associated with neuronal degeneration and altered synapse stability. The disassembly of the NMJ in stathmin includes a predictable sequence of cytological events, suggesting that a common program of synapse disassembly is induced following the loss of Stathmin protein. These data define a required function for Stathmin during synapse maintenance in a model system in which there is only a single stathmin gene, enabling future genetic investigation of Stathmin function with potential relevance to the cause and progression of neuromuscular degenerative disease.

  15. Dynamics and Control of a Class of Underactuated Mechanical Systems

    OpenAIRE

    Reyhanoglu, Mahmut; van der Schaft, Arjan; McClamroch, N. Harris; Kolmanovsky, Ilya

    1999-01-01

    This paper presents a theoretical framework for the dynamics and control of underactuated mechanical systems, defined as systems with fewer inputs than degrees of freedom. Control system formulation of underactuated mechanical systems is addressed and a class of underactuated systems characterized by nonintegrable dynamics relations is identified. Controllability and stabilizability results are derived for this class of underactuated systems. Examples are included to illustrate the results; t...

  16. Control of a mechanical gripper with a fuzzy controller; Control de una garra robotizada mediante un controlador borroso

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, J.; Barcala, J.M.; Gamero, E.; Navarrete, J.J.

    1995-07-01

    A fuzzy logic system is used to control a mechanical gripper. System is based in a NLX230 fuzzy micro controller. Control rules are programmed by a 68020 microprocessor in the micro controller memory. Stress and its derived are used as feedback signals in the control. This system can adapt its effort to the mechanical resistance of the object between the fingers. (Author)

  17. Control of a mechanical gripper with a fuzzy controller; Control de una garra robotizada mediante un controlador borroso

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, J.; Barcala, J.M.; Gamero, E.; Navarrete, J.J.

    1995-07-01

    A fuzzy logic system is used to control a mechanical gripper. System is based in a NLX230 fuzzy micro controller. Control rules are programmed by a 68020 microprocessor in the micro controller memory. Stress and its derived are used as feedback signals in the control. This system can adapt its effort to the mechanical resistance of the object between the fingers.

  18. Neuromuscular adaptations to training, injury and passive interventions: implications for running economy.

    Science.gov (United States)

    Bonacci, Jason; Chapman, Andrew; Blanch, Peter; Vicenzino, Bill

    2009-01-01

    Performance in endurance sports such as running, cycling and triathlon has long been investigated from a physiological perspective. A strong relationship between running economy and distance running performance is well established in the literature. From this established base, improvements in running economy have traditionally been achieved through endurance training. More recently, research has demonstrated short-term resistance and plyometric training has resulted in enhanced running economy. This improvement in running economy has been hypothesized to be a result of enhanced neuromuscular characteristics such as improved muscle power development and more efficient use of stored elastic energy during running. Changes in indirect measures of neuromuscular control (i.e. stance phase contact times, maximal forward jumps) have been used to support this hypothesis. These results suggest that neuromuscular adaptations in response to training (i.e. neuromuscular learning effects) are an important contributor to enhancements in running economy. However, there is no direct evidence to suggest that these adaptations translate into more efficient muscle recruitment patterns during running. Optimization of training and run performance may be facilitated through direct investigation of muscle recruitment patterns before and after training interventions. There is emerging evidence that demonstrates neuromuscular adaptations during running and cycling vary with training status. Highly trained runners and cyclists display more refined patterns of muscle recruitment than their novice counterparts. In contrast, interference with motor learning and neuromuscular adaptation may occur as a result of ongoing multidiscipline training (e.g. triathlon). In the sport of triathlon, impairments in running economy are frequently observed after cycling. This impairment is related mainly to physiological stress, but an alteration in lower limb muscle coordination during running after cycling

  19. Man-machine interface system for neuromuscular training and evaluation based on EMG and MMG signals.

    Science.gov (United States)

    de la Rosa, Ramon; Alonso, Alonso; Carrera, Albano; Durán, Ramon; Fernández, Patricia

    2010-01-01

    This paper presents the UVa-NTS (University of Valladolid Neuromuscular Training System), a multifunction and portable Neuromuscular Training System. The UVa-NTS is designed to analyze the voluntary control of severe neuromotor handicapped patients, their interactive response, and their adaptation to neuromuscular interface systems, such as neural prostheses or domotic applications. Thus, it is an excellent tool to evaluate the residual muscle capabilities in the handicapped. The UVa-NTS is composed of a custom signal conditioning front-end and a computer. The front-end electronics is described thoroughly as well as the overall features of the custom software implementation. The software system is composed of a set of graphical training tools and a processing core. The UVa-NTS works with two classes of neuromuscular signals: the classic myoelectric signals (MES) and, as a novelty, the myomechanic signals (MMS). In order to evaluate the performance of the processing core, a complete analysis has been done to classify its efficiency and to check that it fulfils with the real-time constraints. Tests were performed both with healthy and selected impaired subjects. The adaptation was achieved rapidly, applying a predefined protocol for the UVa-NTS set of training tools. Fine voluntary control was demonstrated to be reached with the myoelectric signals. And the UVa-NTS demonstrated to provide a satisfactory voluntary control when applying the myomechanic signals.

  20. Man-Machine Interface System for Neuromuscular Training and Evaluation Based on EMG and MMG Signals

    Directory of Open Access Journals (Sweden)

    Patricia Fernández

    2010-12-01

    Full Text Available This paper presents the UVa-NTS (University of Valladolid Neuromuscular Training System, a multifunction and portable Neuromuscular Training System. The UVa-NTS is designed to analyze the voluntary control of severe neuromotor handicapped patients, their interactive response, and their adaptation to neuromuscular interface systems, such as neural prostheses or domotic applications. Thus, it is an excellent tool to evaluate the residual muscle capabilities in the handicapped. The UVa-NTS is composed of a custom signal conditioning front-end and a computer. The front-end electronics is described thoroughly as well as the overall features of the custom software implementation. The software system is composed of a set of graphical training tools and a processing core. The UVa-NTS works with two classes of neuromuscular signals: the classic myoelectric signals (MES and, as a novelty, the myomechanic signals (MMS. In order to evaluate the performance of the processing core, a complete analysis has been done to classify its efficiency and to check that it fulfils with the real-time constraints. Tests were performed both with healthy and selected impaired subjects. The adaptation was achieved rapidly, applying a predefined protocol for the UVa-NTS set of training tools. Fine voluntary control was demonstrated to be reached with the myoelectric signals. And the UVa-NTS demonstrated to provide a satisfactory voluntary control when applying the myomechanic signals.

  1. Urgent epidemic control mechanism for aviation networks

    KAUST Repository

    Peng, Chengbin

    2011-01-01

    In the current century, the highly developed transportation system can not only boost the economy, but also greatly accelerate the spreading of epidemics. While some epidemic diseases may infect quite a number of people ahead of our awareness, the health care resources such as vaccines and the medical staff are usually locally or even globally insufficient. In this research, with the network of major aviation routes as an example, we present a method to determine the optimal locations to allocate the medical service in order to minimize the impact of the infectious disease with limited resources. Specifically, we demonstrate that when the medical resources are insufficient, we should concentrate our efforts on the travelers with the objective of effectively controlling the spreading rate of the epidemic diseases. © 2011 Springer-Verlag Berlin Heidelberg.

  2. Mechanical design and control of a new myoelectric hand prosthesis

    NARCIS (Netherlands)

    Peerdeman, B.; Stramigioli, S.; Hekman, E.; Brouwer, D.M.; Misra, S.

    2011-01-01

    The development of modern, myoelectrically controlled hand prostheses can be difficult, due to the many requirements its mechanical design and control system need to fulfill [1]. The hand should be controllable with few input signals, while being able to perform a wide range of motions. It should be

  3. Chemical and mechanical weed control in soybean (Glycine max

    Directory of Open Access Journals (Sweden)

    Weber, Jonas Felix

    2016-02-01

    Full Text Available In this study we investigated the possibility of chemical and mechanical weed control strategies in soybean. Soybean field experiments were carried out in 2013 and 2014 in Southern Germany. Five treatments including common herbicide mixtures and four mechanical weed control treatments, implementing a harrow and a hoe, were tested at different locations. In the herbicide experiments two treatments were applied by PRE emergence herbicides (metribuzin, clomazone, dimethenamid and metribuzin, flufenacet, clomazone and another two treatments were sprayed with a combination of PRE + POST emergence herbicides (metribuzin, flufenacet, thifensulfuron and pendimethalin, thifensulfuron, bentazone, cycloxydim. Furthermore, a POST herbicide treatment was implemented (thifensulfuron, bentazone, thifensulfuron and fluazifop-P-butyl. In the mechanical weed control experiments, treatments were: three times hoeing, PRE emergence harrowing plus three times hoeing, hoeing and harrowing in rotation or three times harrowing. In both experiments an untreated control was included. A 90% weed control efficacy and 23% yield increase was observed in the POST herbicide treatment. PRE + POST treatments resulted in 92% to 99% weed control efficiency and 15% yield increase compared to the untreated control. In the mechanical weed control experiments the combination of PRE emergence harrowing and POST emergence hoeing resulted in 82% weed control efficiency and 34% higher yield compared to the untreated control. Less weed control efficiency (72% was observed in the harrow treatment, leading to 20% higher yield compared to the control. The suitability of both strategies for implementation in “Integrated Weed Management” has been investigated.

  4. Fuzzy control of electro-mechanical gearbox actuator

    Institute of Scientific and Technical Information of China (English)

    G Iordanidis; P H Mellor; D Holliday; P M Churn

    2003-01-01

    In this paper, a prototype direct-drive electro-mechanical actuator is proposed to select gears in a high performance gearbox. Because of the nonlinear behavior of the actuator, a fuzzy logic controller is adopted. The result of simulation has proved that the dynamic response obtained using the fuzzy controller is much faster than that obtained using traditional PD controller.

  5. Physical damping in IDA-PBC controlled underactuated mechanical systems

    NARCIS (Netherlands)

    Gomez-Estern, F.; Schaft, van der A.J.

    2004-01-01

    Energy shaping and passivity-based control designs have proven to be effective in solving control problems for tinderactttated mechanical systems. In recent works, interconnection and damping assignment passivity-based control (IDA-PEC) has been successfully applied to open-loop conservative models,

  6. Sarcocystis fayeri in skeletal muscle of horses with neuromuscular disease.

    Science.gov (United States)

    Aleman, Monica; Shapiro, Karen; Sisó, Silvia; Williams, Diane C; Rejmanek, Daniel; Aguilar, Beatriz; Conrad, Patricia A

    2016-01-01

    Recent reports of Sarcocystis fayeri-induced toxicity in people consuming horse meat warrant investigation on the prevalence and molecular characterization of Sarcocystis spp. infection in horses. Sarcocysts in skeletal muscle of horses have been commonly regarded as an incidental finding. In this study, we investigated the prevalence of sarcocysts in skeletal muscle of horses with neuromuscular disease. Our findings indicated that S. fayeri infection was common in young mature horses with neuromuscular disease and could be associated with myopathic and neurogenic processes. The number of infected muscles and number of sarcocysts per muscle were significantly higher in diseased than in control horses. S. fayeri was predominantly found in low oxidative highly glycolytic myofibers. This pathogen had a high glycolytic metabolism. Common clinical signs of disease included muscle atrophy, weakness with or without apparent muscle pain, gait deficits, and dysphagia in horses with involvement of the tongue and esophagus. Horses with myositis were lethargic, apparently painful, stiff, and reluctant to move. Similar to humans, sarcocystosis and cardiomyopathy can occur in horses. This study did not establish causality but supported a possible association (8.9% of cases) with disease. The assumption of Sarcocysts spp. being an incidental finding in every case might be inaccurate.

  7. Neuromuscular blockade during laparoscopic ventral herniotomy

    DEFF Research Database (Denmark)

    Medici, Roar; Madsen, Matias V; Asadzadeh, Sami;

    2015-01-01

    INTRODUCTION: Laparoscopic herniotomy is the preferred technique for some ventral hernias. Several factors may influence the surgical conditions, one being the depth of neuromuscular blockade (NMB) applied. We hypothesised that deep neuromuscular blockade defined as a post-tetanic count below eight...... would provide a better surgical workspace. METHODS: This was an investigator-initiated, assessor- and patient-blinded randomised cross-over study. A total of 34 patients with planned laparoscopic umbilical, incisional and linea alba herniotomy were studied. Patients would be randomised to receive deep......'s rating of surgical conditions during suturing, duration of surgery and duration of the suturing of the hernia. CONCLUSION: This randomised cross-over study investigated a potential effect on the surgical workspace in laparoscopic ventral herniotomy using deep NMB compared with no NMB. The study may...

  8. Neuromuscular monitoring: old issues, new controversies.

    Science.gov (United States)

    Kopman, Aaron F

    2009-03-01

    "Expert" editorial opinion suggests that objective or quantitative neuromuscular monitors should be used whenever nondepolarizing blocking agents are administered. It is clear that this advice has by and large fallen on deaf ears. A sizeable number of clinicians here (North America) and abroad (Europe) fail to use even conventional peripheral nerve stimulators routinely. This chapter will explore potential reasons for and consequences of this disconnect between academia and "the real world." Along the way, we will examine such questions as how do we define and measure adequate recovery from nondepolarizing block. What are the limitations of clinical tests of recovery such as the "head-lift test?" What is the incidence of undetected postoperative residual curarization (PORC)? Does neuromuscular monitoring reduce the frequency of PORC? How will the availability of sugammadex alter the above discussion?

  9. Mechanical systems a unified approach to vibrations and controls

    CERN Document Server

    Gans, Roger F

    2015-01-01

    This essential textbook covers analysis and control of engineering mechanisms, which include almost any apparatus with moving parts used in daily life, from musical instruments to robots. The text  presents both vibrations and controls with considerable breadth and depth using a unified notation. It strikes a nice balance between the analytical and the practical.  This text contains enough material for a two semester sequence, but it can also be used in a single semester course combining the two topics. Mechanical Systems: A Unified Approach to Vibrations and Controls presents a common notation and approach to these closely related areas. Examples from the both vibrations and controls components are integrated throughout this text. This book also: ·         Presents a unified approach to vibrations and controls, including an excellent diagram that simultaneously discusses embedding classical vibrations (mechanical systems) in a discussion of models, inverse models, and open and closed loop control ...

  10. Mechanism of Attitude Control Device for Floating Object

    OpenAIRE

    辻, 俊明; 大西, 公平

    2003-01-01

    This paper describes the new mechanism on attitude control device for unfixed objects. Flywheel is a common attitude control device on spacecraft that provides precise control at an easy rate. However, rapid response is hardly achieved since low reaction torque is available applying flywheel. The purpose in this paper is to improve the response of attitude control device with flywheel. Brake equipment is mounted on the flywheel in order to raise the maximum torque. Maximum torque is raised dr...

  11. Modeling and Adaptive Control of a Planar Parallel Mechanism

    Institute of Scientific and Technical Information of China (English)

    敖银辉; 陈新

    2004-01-01

    Dynamic model and control strategy of parallel mechanism have always been a problem in robotics research. In this paper,different dynamics formulation methods are discussed first, A model of redundant driven parallel mechanism with a planar parallel manipulator is then constructed as an example. A nonlinear adaptive control method is introduced. Matrix pseudo-inversion is used to get a desired actuator torque from a desired end-effector coordinate while the feedback torque is directly calculated in the actuator space. This treatment avoids forward kinematics computation that is very difficult in a parallel mechanism. Experiments with PID together with the descibed adaptive control strategy were carried out for a planar parallel mechanism. The results show that the proposed adaptive controller outperforms conventional PID methods in tracking desired input at a high speed,

  12. The Integrated Control-Mechanism in ATM-Based Networks

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Survivability is one of the important issues in ATM-based networks since even a single network element failure may cause a serious data loss. This paper introduces a new restoration mechanism based on multi-layer ATM survivable network management architecture. This mechanism integrates the general control and restoration control by establishing the Working VPs logical network, Backup VPs logical network and spare logical network in order to optimally utilize the network resources while maintaining the restoration requirements.

  13. The Design of Wheelchair Lifting Mechanism and Control System

    Institute of Scientific and Technical Information of China (English)

    ZHAO Cong; WANG Zheng-xing; JIANG Shi-hong; ZHANG Li; LIU Zheng-yu

    2014-01-01

    In order to achieve a wheelchair lift function, this paper designs a tri-scissors mechanism. Through the so-called H-type transmission and L-type swing rod, the three scissors mechanisms lift in the same rate with only one liner motor while ensuring the stability of the lift. Finite element analysis in ANSYS is performed to verify the material strength. The control system with Sunplus SCM achieves the voice control of wheelchair walking and lifting.

  14. Synaptic defects in the spinal and neuromuscular circuitry in a mouse model of spinal muscular atrophy.

    Directory of Open Access Journals (Sweden)

    Karen K Y Ling

    Full Text Available Spinal muscular atrophy (SMA is a major genetic cause of death in childhood characterized by marked muscle weakness. To investigate mechanisms underlying motor impairment in SMA, we examined the spinal and neuromuscular circuitry governing hindlimb ambulatory behavior in SMA model mice (SMNΔ7. In the neuromuscular circuitry, we found that nearly all neuromuscular junctions (NMJs in hindlimb muscles of SMNΔ7 mice remained fully innervated at the disease end stage and were capable of eliciting muscle contraction, despite a modest reduction in quantal content. In the spinal circuitry, we observed a ∼28% loss of synapses onto spinal motoneurons in the lateral column of lumbar segments 3-5, and a significant reduction in proprioceptive sensory neurons, which may contribute to the 50% reduction in vesicular glutamate transporter 1(VGLUT1-positive synapses onto SMNΔ7 motoneurons. In addition, there was an increase in the association of activated microglia with SMNΔ7 motoneurons. Together, our results present a novel concept that synaptic defects occur at multiple levels of the spinal and neuromuscular circuitry in SMNΔ7 mice, and that proprioceptive spinal synapses could be a potential target for SMA therapy.

  15. Neuromuscular disorders in zebrafish: state of the art and future perspectives.

    Science.gov (United States)

    Pappalardo, Andrea; Pitto, Letizia; Fiorillo, Chiara; Alice Donati, M; Bruno, Claudio; Santorelli, Filippo M

    2013-06-01

    Neuromuscular disorders are a broad group of inherited conditions affecting the structure and function of the motor system with polymorphic clinical presentation and disease severity. Although individually rare, collectively neuromuscular diseases have an incidence of 1 in 3,000 and represent a significant cause of disability of the motor system. The past decade has witnessed the identification of a large number of human genes causing muscular disorders, yet the underlying pathogenetic mechanisms remain largely unclear, limiting the developing of targeted therapeutic strategies. To overcome this barrier, model systems that replicate the different steps of human disorders are increasingly being developed. Among these, the zebrafish (Danio rerio) has emerged as an excellent organism for studying genetic disorders of the central and peripheral motor systems. In this review, we will encounter most of the available zebrafish models for childhood neuromuscular disorders, providing a brief overview of results and the techniques, mainly transgenesis and chemical biology, used for genetic manipulation. The amount of data collected in the past few years will lead zebrafish to became a common functional tool for assessing rapidly drug efficacy and off-target effects in neuromuscular diseases and, furthermore, to shed light on new etiologies emerging from large-scale massive sequencing studies.

  16. Mechanics and model-based control of advanced engineering systems

    CERN Document Server

    Irschik, Hans; Krommer, Michael

    2014-01-01

    Mechanics and Model-Based Control of Advanced Engineering Systems collects 32 contributions presented at the International Workshop on Advanced Dynamics and Model Based Control of Structures and Machines, which took place in St. Petersburg, Russia in July 2012. The workshop continued a series of international workshops, which started with a Japan-Austria Joint Workshop on Mechanics and Model Based Control of Smart Materials and Structures and a Russia-Austria Joint Workshop on Advanced Dynamics and Model Based Control of Structures and Machines. In the present volume, 10 full-length papers based on presentations from Russia, 9 from Austria, 8 from Japan, 3 from Italy, one from Germany and one from Taiwan are included, which represent the state of the art in the field of mechanics and model based control, with particular emphasis on the application of advanced structures and machines.

  17. An Analytical Dynamics Approach to the Control of Mechanical Systems

    Science.gov (United States)

    Mylapilli, Harshavardhan

    A new and novel approach to the control of nonlinear mechanical systems is presented in this study. The approach is inspired by recent results in analytical dynamics that deal with the theory of constrained motion. The control requirements on the dynamical system are viewed from an analytical dynamics perspective and the theory of constrained motion is used to recast these control requirements as constraints on the dynamical system. Explicit closed form expressions for the generalized nonlinear control forces are obtained by using the fundamental equation of mechanics. The control so obtained is optimal at each instant of time and causes the constraints to be exactly satisfied. No linearizations and/or approximations of the nonlinear dynamical system are made, and no a priori structure is imposed on the nature of nonlinear controller. Three examples dealing with highly nonlinear complex dynamical systems that are chosen from diverse areas of discrete and continuum mechanics are presented to demonstrate the control approach. The first example deals with the energy control of underactuated inhomogeneous nonlinear lattices (or chains), the second example deals with the synchronization of the motion of multiple coupled slave gyros with that of a master gyro, and the final example deals with the control of incompressible hyperelastic rubber-like thin cantilever beams. Numerical simulations accompanying these examples show the ease, simplicity and the efficacy with which the control methodology can be applied and the accuracy with which the desired control objectives can be met.

  18. Influence of intense neuromuscular blockade on surgical conditions during laparotomy

    DEFF Research Database (Denmark)

    Madsen, Matias Vested; Donatsky, Anders Meller; Jensen, Bente Rona

    2015-01-01

    neuromuscular block on surgical conditions with a subjective rating scale, force needed to close the fascia, incidences of abdominal contractions while suctioning the lungs, width of the wound diastase and operating time as outcome parameters. RESULTS: In all six pigs no abdominal contractions occurred while......, operating time and subjective ratings using a four-point rating scale when comparing no neuromuscular block with intense neuromuscular block. However, these outcomes were related to the order of the suturing round. CONCLUSION: Intense neuromuscular block prevented abdominal muscle contractions but did...

  19. Neuromuscular stimulation therapy after incomplete spinal cord injury promotes recovery of interlimb coordination during locomotion

    Science.gov (United States)

    Jung, R.; Belanger, A.; Kanchiku, T.; Fairchild, M.; Abbas, J. J.

    2009-10-01

    The mechanisms underlying the effects of neuromuscular electrical stimulation (NMES) induced repetitive limb movement therapy after incomplete spinal cord injury (iSCI) are unknown. This study establishes the capability of using therapeutic NMES in rodents with iSCI and evaluates its ability to promote recovery of interlimb control during locomotion. Ten adult female Long Evans rats received thoracic spinal contusion injuries (T9; 156 ± 9.52 Kdyne). 7 days post-recovery, 6/10 animals received NMES therapy for 15 min/day for 5 days, via electrodes implanted bilaterally into hip flexors and extensors. Six intact animals served as controls. Motor function was evaluated using the BBB locomotor scale for the first 6 days and on 14th day post-injury. 3D kinematic analysis of treadmill walking was performed on day 14 post-injury. Rodents receiving NMES therapy exhibited improved interlimb coordination in control of the hip joint, which was the specific NMES target. Symmetry indices improved significantly in the therapy group. Additionally, injured rodents receiving therapy more consistently displayed a high percentage of 1:1 coordinated steps, and more consistently achieved proper hindlimb touchdown timing. These results suggest that NMES techniques could provide an effective therapeutic tool for neuromotor treatment following iSCI.

  20. Single-atom quantum control of macroscopic mechanical oscillators

    Science.gov (United States)

    Bariani, F.; Otterbach, J.; Tan, Huatang; Meystre, P.

    2014-01-01

    We investigate a hybrid electromechanical system consisting of a pair of charged macroscopic mechanical oscillators coupled to a small ensemble of Rydberg atoms. The resonant dipole-dipole coupling between an internal atomic Rydberg transition and the mechanics allows cooling to its motional ground state with a single atom despite the considerable mass imbalance between the two subsystems. We show that the rich electronic spectrum of Rydberg atoms, combined with their high degree of optical control, paves the way towards implementing various quantum-control protocols for the mechanical oscillators.

  1. Soft Time-Suboptimal Controlling Structure for Mechanical Systems

    DEFF Research Database (Denmark)

    Kulczycki, Piotr; Wisniewski, Rafal; Kowalski, Piotr

    2004-01-01

    The paper presents conception of a soft control structure based on the time-optimal approach. Its parameters are selected in accordance with the rules of the statistical decision theory and additionally it allows to eliminate rapid changes in control values. The object is a basic mechanical system...

  2. Non-invasive neuromuscular electrical stimulation in patients with central nervous system lesions: an educational review.

    Science.gov (United States)

    Schuhfried, Othmar; Crevenna, Richard; Fialka-Moser, Veronika; Paternostro-Sluga, Tatjana

    2012-02-01

    The aim of this educational review is to provide an overview of the clinical application of transcutaneous electrical stimulation of the extremities in patients with upper motor neurone lesions. In general two methods of electrical stimulation can be distinguished: (i) therapeutic electrical stimulation, and (ii) functional electrical stimulation. Therapeutic electrical stimulation improves neuromuscular functional condition by strengthening muscles, increasing motor control, reducing spasticity, decreasing pain and increasing range of motion. Transcutaneous electrical stimulation may be used for neuromuscular electrical stimulation inducing repetitive muscle contraction, electromyography-triggered neuromuscular electrical stimulation, position-triggered electrical stimulation and subsensory or sensory transcutaneous electric stimulation. Functional electrical stimulation provokes muscle contraction and thereby produces a functionally useful movement during stimulation. In patients with spinal cord injuries or stroke, electrical upper limb neuroprostheses are applied to enhance upper limb and hand function, and electrical lower limb neuroprostheses are applied for restoration of standing and walking. For example, a dropped foot stimulator is used to trigger ankle dorsiflexion to restore gait function. A review of the literature and clinical experience of the use of therapeutic electrical stimulation as well as of functional electrical stimulation in combination with botulinum toxin, exercise therapy and/or splinting are presented. Although the evidence is limited we conclude that neuromuscular electrical stimulation in patients with central nervous system lesions can be an effective modality to improve function, and that combination with other treatments has an additive therapeutic effect.

  3. Whole-body vibration does not influence knee joint neuromuscular function or proprioception.

    Science.gov (United States)

    Hannah, R; Minshull, C; Folland, J P

    2013-02-01

    This study examined the acute effects of whole-body vibration (WBV) on knee joint position sense and indices of neuromuscular function, specifically strength, electromechanical delay and the rate of force development. Electromyography and electrically evoked contractions were used to investigate neural and contractile responses to WBV. Fourteen healthy males completed two treatment conditions on separate occasions: (1) 5 × 1 min of unilateral isometric squat exercise on a synchronous vibrating platform [30 Hz, 4 mm peak-to-peak amplitude] (WBV) and (2) a control condition (CON) of the same exercise without WBV. Knee joint position sense (joint angle replication task) and quadriceps neuromuscular function were assessed pre-, immediately-post and 1 h post-exercise. During maximum voluntary knee extensions, the peak force (PF(V)), electromechanical delay (EMD(V)), rate of force development (RFD(V)) and EMG of the quadriceps were measured. Twitch contractions of the knee extensors were electrically evoked to assess EMD(E) and RFD(E). The results showed no influence of WBV on knee joint position, EMD(V), PF(V) and RFD(V) during the initial 50, 100 or 150 ms of contraction. Similarly, electrically evoked neuromuscular function and neural activation remained unchanged following the vibration exercise. A single session of unilateral WBV did not influence any indices of thigh muscle neuromuscular performance or knee joint proprioception.

  4. The origins of neuromuscular fatigue post-stroke.

    Science.gov (United States)

    Knorr, S; Ivanova, T D; Doherty, T J; Campbell, J A; Garland, S J

    2011-10-01

    Fatigue post-stroke is a disabling and persistent symptom affecting many stroke survivors. Despite its high prevalence, the pathophysiology underlying this phenomenon remains obscure. The aim of the present study was to investigate the origins of neuromuscular fatigue post-stroke. Ten chronic stroke survivors and 10 controls sustained an isometric contraction at 30% of maximal voluntary contraction (MVC) with the ankle dorsiflexors. Motor evoked potential (MEP), cortical silent period (SP), voluntary activation, M wave and contractile properties were evaluated before, during and after fatigue among the paretic, non-paretic and control limbs. The pattern of response to fatigue in the non-paretic and control limbs was comparable; therefore, results are presented between the paretic and non-paretic limbs. Before fatigue, reduced MVC peak torque and MEP amplitude were observed on the paretic side in comparison with the non-paretic side. During fatigue, the cortical SP duration increased significantly in both limbs, whereas the MEP amplitude significantly increased only in the non-paretic limb. After fatigue, MVC peak torque decreased significantly in both limbs. Significant reductions in M wave and twitch peak torque were observed in both limbs, pointing to the development of peripheral fatigue. However, central fatigue, evident by a significant reduction in voluntary activation, was greater in the paretic than in the non-paretic limb. After stroke, an inability to increase central excitability in response to an increased cortical inhibition associated with the fatiguing contraction may contribute to central fatigue observed in the paretic limb, which may also be linked to increased self-reported fatigue during activities of daily living. These findings advance our understanding of the neuromuscular basis of fatigue post-stroke.

  5. The Significance of Sedation Control in Patients Receiving Mechanical Ventilation

    OpenAIRE

    2012-01-01

    Background Adequate assessment and control of sedation play crucial roles in the proper performance of mechanical ventilation. Methods A total of 30 patients with various pulmonary diseases were prospectively enrolled. The study population was randomized into two groups. The sedation assessment group (SAG) received active protocol-based control of sedation, and in the empiric control group (ECG), the sedation levels were empirically adjusted. Subsequently, daily interruption of sedation (DIS)...

  6. Integrated design of cam mechanisms and servo-control systems

    Institute of Scientific and Technical Information of China (English)

    姚燕安[1; 颜鸿森[2; 张策[3; 邹慧君[4

    2000-01-01

    Traditionally, in a cam mechanism, the cam is driven by an actuator at a constant speed. The motion characteristics of the follower are determined once the cam profile is designed. This paper presents a novel theory named "integrated design of cam mechanisms and servo-control systems" whose basic idea is varying the input speed trajectory of the cam by a microcomputer-controlled servomotor to improve kinematic and dynamic characteristics of the follower system. The philosophy of the theory is developing superior machines by taking advantage of the flexibility of servo-control systems to compensate for disadvantages of rigid cam mechanisms. The systematic design criteria of the cam-servo-integrated system are developed and an approach based on optimal-control theory is presented for to select suitable cam speed functions, hence the basis of the theory is formed.

  7. Synthesis of dissipative output feedback controllers. Application to mechanical systems

    Energy Technology Data Exchange (ETDEWEB)

    Johannessen, Erling Aarsand

    1997-12-31

    This thesis presents new results on the synthesis of linear controllers with passivity, or more general, dissipativity properties. These methods may be applied to obtain more accurate control over mechanical systems and in the control of chemical processes that involve dissipative subsystems. The thesis presents two different approaches for synthesis of dissipative controllers: (1) A method that exploits the Riccati equation solution to the state space formulation of the H{sub {infinity}} control problem is investigated, illustrated by synthesising a controller for damping of flexible modes in a beam. (2) A more general method for dissipative control synthesis is developed that retains the well-known techniques of loop-shaping and frequency weighting in H{sub {infinity}}. A method is also presented for controller synthesis directly from frequency response data. 82 refs., 34 figs., 3 tabs.

  8. A synaptic nidogen: Developmental regulation and role of nidogen-2 at the neuromuscular junction

    Directory of Open Access Journals (Sweden)

    Smyth Neil

    2008-09-01

    Full Text Available Abstract Background The skeletal neuromuscular junction is a useful model for elucidating mechanisms that regulate synaptogenesis. Developmentally important intercellular interactions at the neuromuscular junction are mediated by the synaptic portion of a basal lamina that completely ensheaths each muscle fiber. Basal laminas in general are composed of four main types of glycosylated proteins: laminins, collagens IV, heparan sulfate proteoglycans and nidogens (entactins. The portion of the muscle fiber basal lamina that passes between the motor nerve terminal and postsynaptic membrane has been shown to bear distinct isoforms of the first three of these. For laminins and collagens IV, the proteins are deposited by the muscle; a synaptic proteoglycan, z-agrin, is deposited by the nerve. In each case, the synaptic isoform plays key roles in organizing the neuromuscular junction. Here, we analyze the fourth family, composed of nidogen-1 and -2. Results In adult muscle, nidogen-1 is present throughout muscle fiber basal lamina, while nidogen-2 is concentrated at synapses. Nidogen-2 is initially present throughout muscle basal lamina, but is lost from extrasynaptic regions during the first three postnatal weeks. Neuromuscular junctions in mutant mice lacking nidogen-2 appear normal at birth, but become topologically abnormal as they mature. Synaptic laminins, collagens IV and heparan sulfate proteoglycans persist in the absence of nidogen-2, suggesting the phenotype is not secondary to a general defect in the integrity of synaptic basal lamina. Further genetic studies suggest that synaptic localization of each of the four families of synaptic basal lamina components is independent of the other three. Conclusion All four core components of the basal lamina have synaptically enriched isoforms. Together, they form a highly specialized synaptic cleft material. Individually, they play distinct roles in the formation, maturation and maintenance of the

  9. Acute neuromuscular weakness associated with dengue infection

    Directory of Open Access Journals (Sweden)

    Harmanjit Singh Hira

    2012-01-01

    Full Text Available Background: Dengue infections may present with neurological complications. Whether these are due to neuromuscular disease or electrolyte imbalance is unclear. Materials and Methods: Eighty-eight patients of dengue fever required hospitalization during epidemic in year 2010. Twelve of them presented with acute neuromuscular weakness. We enrolled them for study. Diagnosis of dengue infection based on clinical profile of patients, positive serum IgM ELISA, NS1 antigen, and sero-typing. Complete hemogram, kidney and liver functions, serum electrolytes, and creatine phosphokinase (CPK were tested. In addition, two patients underwent nerve conduction velocity (NCV test and electromyography. Results: Twelve patients were included in the present study. Their age was between 18 and 34 years. Fever, myalgia, and motor weakness of limbs were most common presenting symptoms. Motor weakness developed on 2 nd to 4 th day of illness in 11 of 12 patients. In one patient, it developed on 10 th day of illness. Ten of 12 showed hypokalemia. One was of Guillain-Barré syndrome and other suffered from myositis; they underwent NCV and electromyography. Serum CPK and SGOT raised in 8 out of 12 patients. CPK of patient of myositis was 5098 IU. All of 12 patients had thrombocytopenia. WBC was in normal range. Dengue virus was isolated in three patients, and it was of serotype 1. CSF was normal in all. Within 24 hours, those with hypokalemia recovered by potassium correction. Conclusions: It was concluded that the dengue virus infection led to acute neuromuscular weakness because of hypokalemia, myositis, and Guillain-Barré syndrome. It was suggested to look for presence of hypokalemia in such patients.

  10. Molecular mechanism of size control in development and human diseases

    Institute of Scientific and Technical Information of China (English)

    Xiaolong Yang; Tian Xu

    2011-01-01

    How multicellular organisms control their size is a fundamental question that fascinated generations of biologists.In the past 10 years, tremendous progress has been made toward our understanding of the molecular mechanism underlying size control. Original studies from Drosophila showed that in addition to extrinsic nutritional and hormonal cues, intrinsic mechanisms also play important roles in the control of organ size during development. Several novel signaling pathways such as insulin and Hippo-LATS signaling pathways have been identified that control organ size by regulating cell size and/or cell number through modulation of cell growth, cell division, and cell death. Later studies using mammalian cell and mouse models also demonstrated that the signaling pathways identified in flies are also conserved in mammals. Significantly, recent studies showed that dysregulation of size control plays important roles in the development of many human diseases sucha as cancer,diabetes,and hypertrophy.

  11. An Adaptive Variable Structure Control Scheme for Underactuated Mechanical Manipulators

    Directory of Open Access Journals (Sweden)

    Jung Hua Yang

    2012-01-01

    Full Text Available Mechanical arms have been widely used in the industry for many decades. They have played a dominant role in factory automation. However the control performance, or even system stability, would be deteriorated if some of the actuators fail during the operations. Hence, in this study, an adaptive variable structure scheme is presented to solve this problem. It is shown that, by applying the control mechanism proposed in this paper, the motion of robot systems can maintain asymptotical stability in case of actuators failure. The control algorithms as well as the convergence analysis are theoretically proved based on Lyapunov theory. In addition, to demonstrate the validity of the controller, a number of simulations as well as real-time experiments are also performed for Pendubot robot and Furuta robot systems. The results confirm the applicability of the proposed controller.

  12. [Transition experience of patients with neuromuscular disease].

    Science.gov (United States)

    Greif, Valeria; Ugo, Florencia; de Castro Pérez, M Fernanda; Mozzoni, Julieta; Aguerre, Verónica; Saldías, Milagros; Monges, M Soledad

    2017-02-01

    Neuromuscular diseases are mostly genetic disorders, with chronic and progressive course. Affected people are at high risk of developing physical and emotional disabilities. In the last decades, the advance in technology and science has increased chronic pediatric patients survival rate, thus requiring an ongoing assistance in adult hospitals, making the transition a necessity and a challenge. This article reports the clinical practice designed between Hospital Garrahan and Hospital Ramos Mejía for the transition of 27 adolescents during 2015, setting achievements, findings and challenges resulting from this experience.

  13. Desarrollo neuromuscular en la atrofia muscular espinal

    OpenAIRE

    Martínez Hernàndez, Rebeca

    2012-01-01

    INTRODUCCIÓN: La atrofia muscular espinal (AME) es una enfermedad neuromuscular infantil caracterizada por la muerte de las neuronas motoras del asta anterior de la médula espinal. Como consecuencia de ello hay una degeneración y atrofia muscular, por lo que los pacientes mueren a menudo de insuficiencias respiratorias graves. La AME se clasifica en tres tipos principales según el grado de gravedad, la edad de aparición y las pautas motoras. Se trata de una enfermedad con patrón de herencia a...

  14. Control mechanism of double-rotator-structure ternary optical computer

    Science.gov (United States)

    Kai, SONG; Liping, YAN

    2017-03-01

    Double-rotator-structure ternary optical processor (DRSTOP) has two characteristics, namely, giant data-bits parallel computing and reconfigurable processor, which can handle thousands of data bits in parallel, and can run much faster than computers and other optical computer systems so far. In order to put DRSTOP into practical application, this paper established a series of methods, namely, task classification method, data-bits allocation method, control information generation method, control information formatting and sending method, and decoded results obtaining method and so on. These methods form the control mechanism of DRSTOP. This control mechanism makes DRSTOP become an automated computing platform. Compared with the traditional calculation tools, DRSTOP computing platform can ease the contradiction between high energy consumption and big data computing due to greatly reducing the cost of communications and I/O. Finally, the paper designed a set of experiments for DRSTOP control mechanism to verify its feasibility and correctness. Experimental results showed that the control mechanism is correct, feasible and efficient.

  15. Molecular mechanisms controlling the cell cycle in embryonic stem cells.

    Science.gov (United States)

    Abdelalim, Essam M

    2013-12-01

    Embryonic stem (ES) cells are originated from the inner cell mass of a blastocyst stage embryo. They can proliferate indefinitely, maintain an undifferentiated state (self-renewal), and differentiate into any cell type (pluripotency). ES cells have an unusual cell cycle structure, consists mainly of S phase cells, a short G1 phase and absence of G1/S checkpoint. Cell division and cell cycle progression are controlled by mechanisms ensuring the accurate transmission of genetic information from generation to generation. Therefore, control of cell cycle is a complicated process, involving several signaling pathways. Although great progress has been made on the molecular mechanisms involved in the regulation of ES cell cycle, many regulatory mechanisms remain unknown. This review summarizes the current knowledge about the molecular mechanisms regulating the cell cycle of ES cells and describes the relationship existing between cell cycle progression and the self-renewal.

  16. Neuromuscular Adaptations to Unilateral vs. Bilateral Strength Training in Women.

    Science.gov (United States)

    Botton, Cíntia E; Radaelli, Regis; Wilhelm, Eurico N; Rech, Anderson; Brown, Lee E; Pinto, Ronei S

    2016-07-01

    Botton, CE, Radaelli, R, Wilhelm, EN, Rech, A, Brown, LE, and Pinto, RS. Neuromuscular adaptations to unilateral vs. bilateral strength training in women. J Strength Cond Res 30(7): 1924-1932, 2016-Considering the bilateral deficit, the sum of forces produced by each limb in a unilateral condition is generally greater than that produced by them in a bilateral condition. Therefore, it can be speculated that performing unilateral strength exercises may allow greater training workloads and subsequently greater neuromuscular adaptations when compared with bilateral training. Hence, the purpose of this study was to compare neuromuscular adaptations with unilateral vs. bilateral training in the knee extensor muscles. Forty-three recreationally active young women were allocated to a control, unilateral (UG) or bilateral (BG) training group, which performed 2 times strength training sessions a week for 12 weeks. Knee extension one repetition maximum (1RM), maximal isometric strength, muscle electrical activity, and muscle thickness were obtained before and after the study period. Muscle strength was measured in unilateral (right + left) and bilateral tests. Both UG and BG increased similarly their unilateral 1RM (33.3 ± 14.3% vs. 24.6 ± 11.9%, respectively), bilateral 1RM (20.3 ± 6.8% vs. 28.5 ± 12.3%, respectively), and isometric strength (14.7 ± 11.3% vs. 13.1 ± 12.5%, respectively). The UG demonstrated greater unilateral isometric strength increase than the BG (21.4 ± 10.5% vs. 10.3 ± 11.1%, respectively) and only the UG increased muscle electrical activity. Muscle thickness increased similarly for both training groups. Neither group exhibited pretesting 1RM bilateral deficit values, but at post-testing, UG showed a significant bilateral deficit (-6.5 ± 7.8%) whereas BG showed a significant bilateral facilitation (5.9 ± 9.0%). Thus, performing unilateral or bilateral exercises was not a decisive factor for improving morphological adaptations and bilateral

  17. Biomechanical and neuromuscular characteristics of male athletes: implications for the development of anterior cruciate ligament injury prevention programs.

    Science.gov (United States)

    Sugimoto, Dai; Alentorn-Geli, Eduard; Mendiguchía, Jurdan; Samuelsson, Kristian; Karlsson, Jon; Myer, Gregory D

    2015-06-01

    Prevention of anterior cruciate ligament (ACL) injury is likely the most effective strategy to reduce undesired health consequences including reconstruction surgery, long-term rehabilitation, and pre-mature osteoarthritis occurrence. A thorough understanding of mechanisms and risk factors of ACL injury is crucial to develop effective prevention programs, especially for biomechanical and neuromuscular modifiable risk factors. Historically, the available evidence regarding ACL risk factors has mainly involved female athletes or has compared male and female athletes without an intra-group comparison for male athletes. Therefore, the principal purpose of this article was to review existing evidence regarding the investigation of biomechanical and neuromuscular characteristics that may imply aberrant knee kinematics and kinetics that would place the male athlete at risk of ACL injury. Biomechanical evidence related to knee kinematics and kinetics was reviewed by different planes (sagittal and frontal/coronal), tasks (single-leg landing and cutting), situation (anticipated and unanticipated), foot positioning, playing surface, and fatigued status. Neuromuscular evidence potentially related to ACL injury was reviewed. Recommendations for prevention programs for ACL injuries in male athletes were developed based on the synthesis of the biomechanical and neuromuscular characteristics. The recommendations suggest performing exercises with multi-plane biomechanical components including single-leg maneuvers in dynamic movements, reaction to and decision making in unexpected situations, appropriate foot positioning, and consideration of playing surface condition, as well as enhancing neuromuscular aspects such as fatigue, proprioception, muscle activation, and inter-joint coordination.

  18. Long Term Follow-up of Ventilated Patients with Thoracic Restriction and Neuromuscular Disease

    Directory of Open Access Journals (Sweden)

    Dina Brooks

    2002-01-01

    Full Text Available OBJECTIVE: To evaluate the long term effects of home mechanical ventilation (HMV on pulmonary function, nighttime gas exchange, daytime arterial blood gases, sleep architecture and functional exercise capacity (6 min walk. Patients with respiratory failure attributable to thoracic restrictive disease (TRD (kyphoscoliosis or neuromuscular disease (NMD were assessed, ventilated, trained and followed in a dedicated unit for the care of patients requiring long term ventilation.

  19. Abnormalities of neuromuscular transmission in patients with Miller-Fisher syndrome.

    Science.gov (United States)

    Menon, Parvathi; Mahant, Neil; Vucic, Steve

    2012-11-01

    The mechanism of motor weakness in patients with Miller-Fisher syndrome (MFS) remains to be fully elucidated. We performed stimulated single fibre electromyography (sSFEMG) in a clinically weak frontalis muscle in a patient with MFS. Stimulate single fiber EMG revealed increased jitter in over 50% of the apparent single fibre action potentials from the frontalis muscle in addition to increased mean jitter. The findings in the present study suggest dysfunction of neuromuscular transmission in patients with MFS.

  20. Mechanically implementable accommodation matrices for passive force control

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, A. [Univ. of Pennsylvania, Philadelphia, PA (United States). Center for Human Modeling and Simulation; Peshkin, M. [Northwestern Univ., Evanston, IL (United States). Dept. of Mechanical Engineering

    1999-08-01

    Robot force control implemented by means of passive mechanical devices has inherent advantages over active implementations with regard to stability, response rapidity, and physical robustness. The class of devices considered in this paper consists of a Stewart platform-type mechanism interconnected with a network of adjustable mechanical elements such as springs and dampers. The control law repertoire of such a device, imagined as a robot wrist, is given by the range of admittance matrices that it may be programmed to possess. This paper focuses on wrists incorporating damper networks for which the admittance matrices reduce to accommodation or inverse-damping matrices. The authors show that a hydraulic network of fully adjustable damper elements may attain any diagonally dominant accommodation matrix. They describe the technique of selecting the individual damping coefficients to design a desired matrix. They identify the set of dominant matrices as a polyhedral convex cone in the space of matrix entries, and show that each dominant matrix can be composed of a positive linear combination of a fixed set of basis matrices. The overall wrist-accommodation matrix is obtained by projecting the accommodation matrix of the damper network through the wrist kinematics. The linear combination of the dominant basis matrices projected through the wrist kinematics generates the entire space of mechanically implementable force-control laws. The authors quantify the versatility of mechanically implementable force-control laws by comparing this space to the space of all matrices.

  1. Mechanical Impedance Control in the Human Arm While Manually Transporting an Open-Top Fluid Filled Dish

    Directory of Open Access Journals (Sweden)

    Navit Roth

    2011-01-01

    Full Text Available The present study deals with stabilizing aspects of a hand-held dish filled with liquid while walking steadily. This is an attempt to decipher the neuro-muscular strategies employed and the mechanical responses of the arm during certain tasks of manual materials handling. The experimental configuration included a cup and the test-subject’s hand as an ‘end-effector’ of a serial three-link system representing the upper limb. These links are connected together by the wrist, elbow and shoulder joints. The tested subjects walked at constant speed on a treadmill while aiming to minimize liquid spillage from the cup. The motion of the limb and shoulder girdle served as inputs to a model to reveal the impedance adjustments during the simultaneous control of grasping and walking under ordinary conditions, and when one of the joints is affected. A regressive function used to express stiffness, included first-order dependence on angle and on angular velocity. The function used for damping included first-order dependence on angular velocity. Redundancies in the numerical solution were eliminated using multicollinearity diagnostic algorithms. The results revealed that the wrist joint was found to have constant stiffness and damping and no regulation of these coefficients was necessary during gait. Both in the elbow and shoulder joints stiffness included a constant coefficient as well as an angular velocity-dependent coefficient. Although all tested subjects demonstrated ability to prevent spillage of liquid, there was a considerable variability among the results obtained, indicating that the compensatory mechanisms employed by each subject to regulate the mechanical impedance were subjective. These results can help in the optimization of manual materials handeling tasks in industrial settings as well as future design of prosthetic arms, robotic appliances and man machine interfacing devices.

  2. Mechanical Response of DNA–Nanoparticle Crystals to Controlled Deformation

    Science.gov (United States)

    2016-01-01

    The self-assembly of DNA-conjugated nanoparticles represents a promising avenue toward the design of engineered hierarchical materials. By using DNA to encode nanoscale interactions, macroscale crystals can be formed with mechanical properties that can, at least in principle, be tuned. Here we present in silico evidence that the mechanical response of these assemblies can indeed be controlled, and that subtle modifications of the linking DNA sequences can change the Young’s modulus from 97 kPa to 2.1 MPa. We rely on a detailed molecular model to quantify the energetics of DNA–nanoparticle assembly and demonstrate that the mechanical response is governed by entropic, rather than enthalpic, contributions and that the response of the entire network can be estimated from the elastic properties of an individual nanoparticle. The results here provide a first step toward the mechanical characterization of DNA–nanoparticle assemblies, and suggest the possibility of mechanical metamaterials constructed using DNA. PMID:27725959

  3. Design and control of a high precision drive mechanism

    Science.gov (United States)

    Pan, Bo; He, Yongqiang; Wang, Haowei; Zhang, Shuyang; Zhang, Donghua; Wei, Xiaorong; Jiang, Zhihong

    2017-01-01

    This paper summarizes the development of a high precision drive mechanism (HPDM) for space application, such as the directional antenna, the laser communication device, the mobile camera and other pointing mechanisms. In view of the great practical significance of high precision drive system, control technology for permanent magnet synchronous motor (PMSM) servo system is also studied and a PMSM servo controller is designed in this paper. And the software alignment was applied to the controller to eliminate the steady error of the optical encoder, which helps to realize the 1 arcsec (1σ) control precision. To assess its capabilities, the qualification environment testing including the thermal vacuum cycling testing, and the sinusoidal and random vibration were carried out. The testing results show that the performance of the HPDM is almost the same between the former and the end of each testing.

  4. Combination of the Sorting Line Priority Polling Control Mechanism

    Directory of Open Access Journals (Sweden)

    Wenxue Ran

    2013-10-01

    Full Text Available The paper proposed the priority polling control mechanism of the unit material combinations sorting lines, and sorters operating process is understood to be the arrival process of orders, service process of each sorter sorts orders and the conversion process between sorting machines. Control process, sorters of the combined sorting lines are divided into the priority sorters and ordinary sorters, priority sorters use full service control, ordinary sorters use limited service (k = 1, applies the polling service system theory, through the embedded Markov chain and probability generating function to establish the mathematical model of the system, the exact solution of the control mechanism of the polling system model and the first and second characteristic parameters, combined with the actual production priority parameters of orders picking for simulation analysis

  5. Electrophysiological study in neuromuscular junction disorders

    Directory of Open Access Journals (Sweden)

    Ajith Cherian

    2013-01-01

    Full Text Available This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS, congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS. SFEMG requires skill and patience and its availability is limited to a few centers. For RNS supramaximal stimulation is essential and so is display of the whole waveform of each muscle response at maximum amplitude. The amplitudes of the negative phase of the first and fourth responses are measured from baseline to negative peak, and the percent change of the fourth response compared with the first represents the decrement or increment. A decrement greater than 10% is accepted as abnormal and smooth progression of response amplitude train and reproducibility form the crux. In suspected LEMS the effect of fast rates of stimulation should be determined after RNS response to slow rates of stimulation. Caution is required to avoid misinterpretation of potentiation and pseudofacilitation.

  6. Neuromuscular imaging in inherited muscle diseases

    Energy Technology Data Exchange (ETDEWEB)

    Wattjes, Mike P. [VU University Medical Center, Department of Radiology, De Boelelaan 1117, HV, Amsterdam (Netherlands); Kley, Rudolf A. [Klinken Bergmannsheil, Ruhr-University, Department of Neurology, Neuromuscular Centre Ruhrgebiet, Bochum (Germany); Fischer, Dirk [University Hospital of Basel, Department of Neurology, Basel (Switzerland); University Children' s Hospital Basel, Department of Neuropaediatrics, Basel (Switzerland)

    2010-10-15

    Driven by increasing numbers of newly identified genetic defects and new insights into the field of inherited muscle diseases, neuromuscular imaging in general and magnetic resonance imaging (MRI) in particular are increasingly being used to characterise the severity and pattern of muscle involvement. Although muscle biopsy is still the gold standard for the establishment of the definitive diagnosis, muscular imaging is an important diagnostic tool for the detection and quantification of dystrophic changes during the clinical workup of patients with hereditary muscle diseases. MRI is frequently used to describe muscle involvement patterns, which aids in narrowing of the differential diagnosis and distinguishing between dystrophic and non-dystrophic diseases. Recent work has demonstrated the usefulness of muscle imaging for the detection of specific congenital myopathies, mainly for the identification of the underlying genetic defect in core and centronuclear myopathies. Muscle imaging demonstrates characteristic patterns, which can be helpful for the differentiation of individual limb girdle muscular dystrophies. The aim of this review is to give a comprehensive overview of current methods and applications as well as future perspectives in the field of neuromuscular imaging in inherited muscle diseases. We also provide diagnostic algorithms that might guide us through the differential diagnosis in hereditary myopathies. (orig.)

  7. NEUROMUSCULAR AND CARDIOVASCULAR EFFECTS OF NEOSTIGMINE AND METHYL-ATROPINE ADMINISTERED AT DIFFERENT DEGREES OF ROCURONIUM-INDUCED NEUROMUSCULAR BLOCK

    NARCIS (Netherlands)

    VANDENBROEK, L; PROOST, JH; WIERDA, JMKH; NJOO, MD; HENNIS, PJ

    1994-01-01

    The neuromuscular and cardiovascular effects of neostigmine, 40 mug kg-1, and methyl-atropine, 7 mug kg-1, administered at different degrees of rocuronium-induced (600 mug kg-1) neuromuscular block were evaluated. In one group of patients spontaneous recovery was awaited (Group A; n = 20). Neostigmi

  8. Mechanisms of active control for noise inside a vibrating cylinder

    Science.gov (United States)

    Lester, Harold C.; Fuller, Chris R.

    1987-01-01

    The active control of propeller-induced noise fields inside a flexible cylinder is studied with attention given to the noise reduction mechanisms inherent in the present coupled acoustic shell model. The active noise control model consists of an infinitely long aluminum cylinder with a radius of 0.4 m and a thickness of 0.001 m. Pressure maps are shown when the two external sources are driven in-phase at a frequency corresponding to Omega = 0.22.

  9. Control of a perturbed under-actuated mechanical system

    KAUST Repository

    Zayane, Chadia

    2015-11-05

    In this work, the trajectory tracking problem for an under-actuated mechanical system in presence of unknown input disturbances is addressed. The studied inertia wheel inverted pendulum falls in the class of non minimum phase systems. The proposed high order sliding mode control architecture including a controller and differentiator allows to track accurately the predefined trajectory and to stabilize the internal dynamics. The robustness of the proposed approach is illustrated through different perturbation and output noise configurations.

  10. The response of cortical alpha activity to pain and neuromuscular changes caused by exercise-induced muscle damage.

    Science.gov (United States)

    Plattner, K; Lambert, M I; Tam, N; Baumeister, J

    2014-02-01

    Exercise-induced muscle damage (EIMD) is characterized by pain, swelling, and shortening of the muscle; increased serum creatine kinase; decreased force output; and altered neuromuscular function. The aim of this study was to investigate the effects of EIMD to determine the relationship between the peripheral symptoms, neuromuscular changes, and delayed pain sensation during a submaximal movement of the biceps brachii on cortical alpha (α) activity. In contrast to the control (n = 12) group, the experimental (n = 16) group participated in an EIMD protocol, and both groups were monitored for 132 h post-EIMD protocol. At 12 h, neuromuscular functioning was already disturbed while the sensation of pain was perceived, but not fully developed. Muscle pain scores in the experimental group peaked after 36 h with the lowest torque reported at 12 h. α-1 activity increased significantly in the motor and somatosensory area 12 h post-EIMD while α-2 activity increased in the contralateral fronto-central area. At 36 h, pain had further increased and neuromuscular function improved while α-1 and α-2 activities had decreased. We hypothesize that α-1 activity over the motor and somatosensory cortex of the experimental group displays a compensatory increase in response to the changes in neuromuscular function during movement, while an increase in α-2 activity is related to the suppression of pain experienced within the first 12 h.

  11. Deficits in Endogenous Adenosine Formation by Ecto-5′-Nucleotidase/CD73 Impair Neuromuscular Transmission and Immune Competence in Experimental Autoimmune Myasthenia Gravis

    Directory of Open Access Journals (Sweden)

    Laura Oliveira

    2015-01-01

    Full Text Available AMP dephosphorylation via ecto-5′-nucleotidase/CD73 is the rate limiting step to generate extracellular adenosine (ADO from released adenine nucleotides. ADO, via A2A receptors (A2ARs, is a potent modulator of neuromuscular and immunological responses. The pivotal role of ecto-5′-nucleotidase/CD73, in controlling extracellular ADO formation, prompted us to investigate its role in a rat model of experimental autoimmune myasthenia gravis (EAMG. Results show that CD4+CD25+FoxP3+ regulatory T cells express lower amounts of ecto-5′-nucleotidase/CD73 as compared to controls. Reduction of endogenous ADO formation might explain why proliferation of CD4+ T cells failed upon blocking A2A receptors activation with ZM241385 or adenosine deaminase in EAMG animals. Deficits in ADO also contribute to neuromuscular transmission failure in EAMG rats. Rehabilitation of A2AR-mediated immune suppression and facilitation of transmitter release were observed by incubating the cells with the nucleoside precursor, AMP. These findings, together with the characteristic increase in serum adenosine deaminase activity of MG patients, strengthen our hypothesis that the adenosinergic pathway may be dysfunctional in EAMG. Given that endogenous ADO formation is balanced by ecto-5′-nucleotidase/CD73 activity and that A2ARs exert a dual role to restore use-dependent neurocompetence and immune suppression in myasthenics, we hypothesize that stimulation of the two mechanisms may have therapeutic potential in MG.

  12. Combined application of neuromuscular electrical stimulation and voluntary muscular contractions.

    Science.gov (United States)

    Paillard, Thierry

    2008-01-01

    Electromyostimulation (EMS) and voluntary muscle contraction (VC) constitute different modes of muscle activation and induce different acute physiological effects on the neuromuscular system. Long-term application of each mode of muscle activation can produce different muscle adaptations. It seems theoretically possible to completely or partially cumulate the muscle adaptations induced by each mode of muscle activation applied separately. This work consisted of examining the literature concerning the muscle adaptations induced by long-term application of the combined technique (CT) [i.e. EMS is combined with VC - non-simultaneously] compared with VC and/or EMS alone in healthy subjects and/or athletes and in post-operative knee-injured subjects. In general, CT induced greater muscular adaptations than VC whether in sports training or rehabilitation. This efficiency would be due to the fact that CT can facilitate cumulative effects of training completely or partially induced by VC and EMS practiced alone. CT also provides a greater improvement of the performance of complex dynamic movements than VC. However, EMS cannot improve coordination between different agonistic and antagonistic muscles and thus does not facilitate learning the specific coordination of complex movements. Hence, EMS should be combined with specific sport training to generate neuromuscular adaptations, but also allow the adjustment of motor control during a voluntary movement. Likewise, in a therapeutic context, CT was particularly efficient to accelerate recovery of muscle contractility during a rehabilitation programme. Strength loss and atrophy inherent in a traumatism and/or a surgical operation would be more efficiently compensated with CT than with VC. Furthermore, CT also restored more functional abilities than VC. Finally, in a rehabilitation context, EMS is complementary to voluntary exercise because in the early phase of rehabilitation it elicits a strength increase, which is necessary

  13. Neuromuscular anatomy and evolution of the cetacean forelimb.

    Science.gov (United States)

    Cooper, Lisa Noelle; Dawson, Susan D; Reidenberg, Joy S; Berta, Annalisa

    2007-09-01

    The forelimb of cetaceans (whales, dolphins, and porpoises) has been radically modified during the limb-to-flipper transition. Extant cetaceans have a soft tissue flipper encasing the manus and acting as a hydrofoil to generate lift. The neuromuscular anatomy that controls flipper movement, however, is poorly understood. This study documents flipper neuromuscular anatomy and tests the hypothesis that antebrachial muscle robustness is related to body size. Data were gathered during dissections of 22 flippers, representing 15 species (7 odontocetes, 15 mysticetes). Results were compared with published descriptions of both artiodactyls and secondarily aquatic vertebrates. Results indicate muscle robustness is best predicted by taxonomic distribution and is not a function of body size. All cetaceans have atrophied triceps muscles, an immobile cubital joint, and lack most connective tissue structures and manus muscles. Forelimbs retain only three muscle groups: triceps (only the scapular head is functional as the humeral heads are vestigal), and antebrachial extensors and flexors. Well-developed flexor and extensor muscles were found in mysticetes and basal odontocetes (i.e., physeterids, kogiids, and ziphiids), whereas later diverging odontocetes (i.e., monodontids, phocoenids, and delphinids) lack or reduce these muscles. Balaenopterid mysticetes (e.g., fin and minke whales) may actively change flipper curvature, while basal odontocetes (e.g., sperm and beaked whales) probably stiffen the flipper through isometric contraction. Later diverging odontocetes lack musculature supporting digital movements and are unable to manipulate flipper curvature. Cetacean forelimbs are unique in that they have lost agility and several soft tissue structures, but retain sensory innervations.

  14. Two- and 6-minute walk tests assess walking capability equally in neuromuscular diseases

    DEFF Research Database (Denmark)

    Andersen, Linda Kahr; Knak, Kirsten Lykke; Witting, Nanna;

    2016-01-01

    to participate on 2 test days, each consisting of 1 2MWT and 1 6MWT separated by a minimum 30-minute period of rest. The order of the walk tests was randomly assigned via sealed envelopes. A group of 38 healthy controls completed 1 6MWT. RESULTS: The mean walking distance for the 2MWT was 142.8 meters......OBJECTIVE: This methodologic study investigates if the 2-minute walk test (2MWT) can be a valid alternative to the 6-minute walk test (6MWT) to describe walking capability in patients with neuromuscular diseases. METHODS: Patients (n = 115) with different neuromuscular diseases were invited...... and for the 6MWT 405.3 meters. The distance walked in the 2MWT was highly correlated to the distance walked in the 6MWT (r = 0.99, p minute in the 6MWT, both among patients and healthy controls, which was not evident in the 2MWT...

  15. Effects of intensive physical rehabilitation on neuromuscular adaptations in adults with poststroke hemiparesis

    DEFF Research Database (Denmark)

    Andersen, Lars L; Zeeman, Peter; Jørgensen, Jørgen R;

    2011-01-01

    with hemiparesis after stroke participated in 12 weeks of intensive physical rehabilitation comprising unilateral high-intensity strength training with near-maximal loads (4-12 repetition maximum) and body weight supported treadmill training. At baseline and 12-week follow-up, the patients went through testing...... the effect of intensive physical rehabilitation on neuromuscular and functional adaptations in outpatients suffering from hemiparesis after stroke. A within-subject repeated-measures design with the paretic leg as the experimental leg and the nonparetic leg as the control leg was used. Eleven outpatients...... observed in the nonparetic control leg. Gait performance increased 52-68%. In conclusion, intensive physical rehabilitation after stroke leads to clinically relevant neuromuscular improvements, leading to increased voluntary strength during a wide range of contraction modes and velocities, and improved...

  16. Contribución del soporte nutricional al tratamiento de las alteraciones neuro-musculares del paciente crítico Contribution of nutritional support to treatment neuromuscular impairments of critically ill patients

    OpenAIRE

    J. C. Montejo González

    2006-01-01

    Las alteraciones neuromusculares que tienen lugar en el paciente crítico han sido atribuidas a factores como la situación séptica, la liberación de mediadores inflamatorioso el empleo de fármacos que afectan desfavorablemente a la función neuro-muscular. El papel de factores metabólicos y nutricionales en el desarrollo de esta patología ha recibido poca atención. En la actualidad, el empleo de protocolos de control intensivo de la glucemia podría tener gran interés en la prevención de las alt...

  17. Improvement Research of Control Rod Drive Mechanism in CARR

    Institute of Scientific and Technical Information of China (English)

    ZHU; Xue-wei; ZHEN; Jian-xiao; LUO; Zhong; YANG; Kun; WANG; Yi-shi; JIA; Yue-guang

    2013-01-01

    We take an improvement research of synchronization in process of control rod drive mechanism(CRDM)inversion.An experimental prototype is designed based on the structure and function of the CRDM,we take some experiments on this experimental prototype,such as maximum loading force experiment,coil temperature rise experiment and stiffness experiment,achieve important magnetic

  18. Mechanism and control of Genipa americana seed germination

    NARCIS (Netherlands)

    Queiroz, S.E.E.; Silva, da E.A.A.; Davide, A.C.; Jose, A.C.; Silva, A.T.; Fraiz, A.C.R.; Faria, J.M.R.; Hilhorst, H.W.M.

    2012-01-01

    Genipa americana (Rubiaceae) is important for restoration of riparian forest in the Brazilian Cerrado. The objective was to characterize the mechanism and control of germination of G. americana to support uniform seedling production. Morphology and morphometrics of seeds, embryo and endosperm were a

  19. Quasivelocities and Optimal Control for Underactuated Mechanical Systems

    CERN Document Server

    Colombo, L

    2010-01-01

    This paper is concerned with the application of the theory of quasivelocities for optimal control for underactuated mechanical systems. Using this theory, we convert the original problem in a variational second-order lagrangian system subjected to constraints. The equations of motion are geometrically derived using an adaptation of the classical Skinner and Rusk formalism.

  20. Quasivelocities and Optimal Control for underactuated Mechanical Systems

    Science.gov (United States)

    Colombo, L.; de Diego, D. Martín

    2010-07-01

    This paper is concerned with the application of the theory of quasivelocities for optimal control for underactuated mechanical systems. Using this theory, we convert the original problem in a variational second-order lagrangian system subjected to constraints. The equations of motion are geometrically derived using an adaptation of the classical Skinner and Rusk formalism.

  1. Fluid Mechanics of Wing Adaptation for Separation Control

    Science.gov (United States)

    Chandrasekhara, M. S.; Wilder, M. C.; Carr, L. W.; Davis, Sanford S. (Technical Monitor)

    1997-01-01

    The unsteady fluid mechanics associated with use of a dynamically deforming leading edge airfoil for achieving compressible flow separation control has been experimentally studied. Changing the leading edge curvature at rapid rates dramatically alters the flow vorticity dynamics which is responsible for the many effects observed in the flow.

  2. Context-Based E-Health System Access Control Mechanism

    Science.gov (United States)

    Al-Neyadi, Fahed; Abawajy, Jemal H.

    E-Health systems logically demand a sufficiently fine-grained authorization policy for access control. The access to medical information should not be just role-based but should also include the contextual condition of the role to access data. In this paper, we present a mechanism to extend the standard role-based access control to incorporate contextual information for making access control decisions in e-health application. We present an architecture consisting of authorisation and context infrastructure that work cooperatively to grant access rights based on context-aware authorization policies and context information.

  3. Pressure and volume controlled mechanical ventilation in anaesthetized pregnant sheep.

    Science.gov (United States)

    Davis, J; Musk, G C

    2014-10-01

    Optimal mechanical ventilation of the pregnant ewe during anaesthesia is of vital importance for maintaining fetal viability. This study aimed to compare peak inspiratory pressure (PIP), oxygenation and cardiovascular parameters with pressure-control (PCV) or volume-control (VCV) mechanical ventilation of anaesthetized pregnant sheep. Twenty ewes at 110 days gestation underwent general anaesthesia in dorsal recumbency for fetal surgery in a research setting. All the sheep were mechanically ventilated; one group with PCV (n = 10) and another with VCV (n = 10) to maintain normocapnia. PIP, direct arterial blood pressure, heart rate, arterial pH and arterial oxygen tension were recorded. PIP was lower in the PCV group (P sheep anaesthetized in dorsal recumbency, though PCV may provide superior oxygenation at a lower PIP.

  4. The Effect of Headquarter Integration Mechanisms on Subsidiaries’ New Product Success: From Control to Coordination Mechanism

    Directory of Open Access Journals (Sweden)

    Firmanzah

    2007-10-01

    Full Text Available New product launching (NPL to the local market by subsidiary managers is a strategic activity, which requires organizational supports from MNC global network. The NPL activity is marked by high level of uncertainty, risk, and market failure. Thus, a headquarter needs to integrate the subsidiary NPL into global strategy. There are two mechanisms to integrate subsidiaries’ activities during NPL process; coordination and control process. By testing the effect of each mechanism on role clarity and functional conflict, I found that coordination mechanism increase role clarity between headquarter and subsidiaries’ managers. In contrast, exercising control mechanism reduces role clarity and functional conflict between headquarter and subsidiaries’ managers during NPL. This research shows that both role clarity and functional conflict increase new product commercial performance introduced by subsidiary in the local market.

  5. Design of low-cost general purpose microcontroller based neuromuscular stimulator.

    Science.gov (United States)

    Koçer, S; Rahmi Canal, M; Güler, I

    2000-04-01

    In this study, a general purpose, low-cost, programmable, portable and high performance stimulator is designed and implemented. For this purpose, a microcontroller is used in the design of the stimulator. The duty cycle and amplitude of the designed system can be controlled using a keyboard. The performance test of the system has shown that the results are reliable. The overall system can be used as the neuromuscular stimulator under safe conditions.

  6. A New Lyapunov Based Robust Control for Uncertain Mechanical Systems

    Institute of Scientific and Technical Information of China (English)

    ZHEN Sheng-Chao; ZHAO Han; CHEN Ye-Hwa; HUANG Kang

    2014-01-01

    We design a new robust controller for uncertain mechanical systems. The inertia matrix0s singularity and upper bound property are first analyzed. It is shown that the inertia matrix may be positive semi-definite due to over-simplified model. Further-more, the inertia matrix0s being uniformly bounded above is also limited. A robust controller is proposed to suppress the effect of uncertainty in mechanical systems with the assumption of uniform positive definiteness and upper bound of the inertia matrix. We theoretically prove that the robust control renders uniform boundedness and uniform ultimate boundedness. The size of the ultimate boundedness ball can be made arbitrarily small by the designer. Simulation results are presented and discussed.

  7. Does perioperative tactile evaluation of the train-of-four response influence the frequency of postoperative residual neuromuscular blockade?

    DEFF Research Database (Denmark)

    Pedersen, T; Viby-Mogensen, J; Bang, U

    1990-01-01

    The authors conducted a randomized controlled clinical trial to evaluate the usefulness of perioperative manual evaluation of the response to train-of-four (TOF) nerve stimulation. A total of 80 patients were divided into four groups of 20 each. For two groups (one given vecuronium and one...... pancuronium), the anesthetists assessed the degree of neuromuscular blockade during operation and during recovery from neuromuscular blockade by manual evaluation of the response to TOF nerve stimulation. In the other two groups, one of which received vecuronium and the other pancuronium, the anesthetists...

  8. Effects of evidence-based prevention training on neuromuscular and biomechanical risk factors for ACL injury in adolescent female athletes

    DEFF Research Database (Denmark)

    Zebis, Mette K; Andersen, Lars L; Brandt, Mikkel;

    2016-01-01

    BACKGROUND: Adolescent female football and handball players are among the athletes with the highest risk of sustaining anterior cruciate ligament (ACL) injuries. AIM: This study evaluated the effects of evidence-based lower extremity injury prevention training on neuromuscular and biomechanical...... risk factors for non-contact ACL injury. METHODS: 40 adolescent female football and handball players (15-16 years) were randomly allocated to a control group (CON, n=20) or neuromuscular training group (NMT, n=20). The NMT group performed an injury prevention programme as a warm-up before their usual...

  9. Optimal piezo-electro-mechanical coupling to control plate vibrations

    CERN Document Server

    Alessandroni, S; Frezza, F

    2010-01-01

    A new way of coupling electrical and mechanical waves, using piezoelectric effect, is presented here. Since the energy exchange between two systems supporting wave propagation is maximum when their evolution is governed by similar equations, hence, an optimal electromechanical coupling is obtained by designing an electric network which is "analog" to the mechanical structure to be controlled. In this paper, we exploit this idea to enhance the coupling, between a Kirchhoff-Love plate and one possible synthesis of its circuital analog, as obtained by means of a set of piezoelectric actuators uniformly distributed upon the plate. It is shown how this approach allows for an optimal energy exchange between the mechanic and the electric forms independent of the modal evolution of the structure. Moreover, we show how an efficient electric dissipation of the mechanical energy can be obtained adding dissipative elements in the electric network.

  10. Control of autoresonance in mechanical and physical models

    Science.gov (United States)

    Kovaleva, A.

    2017-03-01

    Autoresonant energy transfer has been considered as one of the most effective methods of excitation and control of high-energy oscillations for a broad range of physical and engineering systems. Nonlinear time-invariant feedback control provides effective self-tuning and self-adaptation mechanisms targeted at preserving resonance oscillations under variations of the system parameters but its implementation may become extremely complicated. A large class of systems can avoid nonlinear feedback, still producing the required state due to time-variant feed-forward frequency control. This type of control in oscillator arrays employs an intrinsic property of a nonlinear oscillator to vary both its amplitude and the frequency when the driving frequency changes. This paper presents a survey of recently published and new results studying possibilities and limitations of time-variant frequency control in nonlinear oscillator arrays. This article is part of the themed issue 'Horizons of cybernetical physics'.

  11. The influence of gender on neuromuscular pre-activity during side-cutting

    DEFF Research Database (Denmark)

    Bencke, Jesper; Zebis, Mette K

    2011-01-01

    investigated. This cross-sectional study aimed to examine gender differences in neuromuscular pre-activity during a maneuver that mimics a movement associated with the incidence of ACL injuries. Twenty-four team handball players (12 male and 12 female) with no history of ACL injury were tested for EMG pre......It is well established that female athletes are at increased risk for sustaining ACL injuries in sports, where sudden changes of direction are a frequent movement pattern. The underlying neuromuscular mechanisms related to the elevated ACL injury rate in female athletes has yet to be fully......-activity of vastus lateralis, vastus medialis, semitendinosus, and biceps femoris during a side-cutting maneuver. Mean EMG amplitude 50ms prior to toe down was normalized to maximal EMG obtained during maximal isometric contraction. The results showed that females had significantly lower hamstring EMG pre...

  12. Neuromuscular blockade in cardiac surgery: An update for clinicians

    Directory of Open Access Journals (Sweden)

    Hemmerling Thomas

    2008-01-01

    Full Text Available There have been great advancements in cardiac surgery over the last two decades; the widespread use of off-pump aortocoronary bypass surgery, minimally invasive cardiac surgery, and robotic surgery have also changed the face of cardiac anaesthesia. The concept of "Fast-track anaesthesia" demands the use of nondepolarising neuromuscular blocking drugs with short duration of action, combining the ability to provide (if necessary sufficiently profound neuromuscular blockade during surgery and immediate re-establishment of normal neuromuscular transmission at the end of surgery. Postoperative residual muscle paralysis is one of the major hurdles for immediate or early extubation after cardiac surgery. Nondepolarising neuromuscular blocking drugs for cardiac surgery should therefore be easy to titrate, of rapid onset and short duration of action with a pathway of elimination independent from hepatic or renal dysfunction, and should equally not affect haemodynamic stability. The difference between repetitive bolus application and continuous infusion is outlined in this review, with the pharmacodynamic and pharmacokinetic characteristics of vecuronium, pancuronium, rocuronium, and cisatracurium. Kinemyography and acceleromyography are the most important currently used neuromuscular monitoring methods. Whereas monitoring at the adductor pollicis muscle is appropriate at the end of surgery, monitoring of the corrugator supercilii muscle better reflects neuromuscular blockade at more central, profound muscles, such as the diaphragm, larynx, or thoraco-abdominal muscles. In conclusion, cisatracurium or rocuronium is recommended for neuromuscular blockade in modern cardiac surgery.

  13. Sex alters impact of repeated bouts of sprint exercise on neuromuscular activity in trained athletes.

    Science.gov (United States)

    Billaut, François; Smith, Kurt

    2009-08-01

    This study characterized the effect of sex on neuromuscular activity during repeated bouts of sprint exercise. Thirty-three healthy male and female athletes performed twenty 5-s cycle sprints separated by 25 s of rest. Mechanical work and integrated electromyograhs (iEMG) of 4 muscles of the dominant lower limb were calculated in every sprint. The iEMG signals from individual muscles were summed to represent overall electrical activity of these muscles (sum-iEMG). Neuromuscular efficiency (NME) was calculated as the ratio of mechanical work and sum-iEMG for every sprint. Arterial oxygen saturation was estimated (SpO2) with pulse oximetry throughout the protocol. The sprint-induced work decrement (18.9% vs. 29.6%; p women than for the men. However, the sprints decreased NME (10.1%; p men, R2 = 0.87; women, R2 = 0.91; all p sprint exercise is not likely to be explained by a difference in muscle contractility impairment in men and women, but may be due to a sex difference in muscle recruitment strategy. We speculate that women would be less sensitive to arterial O2 desaturation than men, which may trigger lower neuromuscular adjustments to exhaustive exercise.

  14. Spinal mechanisms may provide a combination of intermittent and continuous control of human posture: predictions from a biologically based neuromusculoskeletal model.

    Directory of Open Access Journals (Sweden)

    Leonardo Abdala Elias

    2014-11-01

    Full Text Available Several models have been employed to study human postural control during upright quiet stance. Most have adopted an inverted pendulum approximation to the standing human and theoretical models to account for the neural feedback necessary to keep balance. The present study adds to the previous efforts in focusing more closely on modelling the physiological mechanisms of important elements associated with the control of human posture. This paper studies neuromuscular mechanisms behind upright stance control by means of a biologically based large-scale neuromusculoskeletal (NMS model. It encompasses: i conductance-based spinal neuron models (motor neurons and interneurons; ii muscle proprioceptor models (spindle and Golgi tendon organ providing sensory afferent feedback; iii Hill-type muscle models of the leg plantar and dorsiflexors; and iv an inverted pendulum model for the body biomechanics during upright stance. The motor neuron pools are driven by stochastic spike trains. Simulation results showed that the neuromechanical outputs generated by the NMS model resemble experimental data from subjects standing on a stable surface. Interesting findings were that: i an intermittent pattern of muscle activation emerged from this posture control model for two of the leg muscles (Medial and Lateral Gastrocnemius; and ii the Soleus muscle was mostly activated in a continuous manner. These results suggest that the spinal cord anatomy and neurophysiology (e.g., motor unit types, synaptic connectivities, ordered recruitment, along with the modulation of afferent activity, may account for the mixture of intermittent and continuous control that has been a subject of debate in recent studies on postural control. Another finding was the occurrence of the so-called "paradoxical" behaviour of muscle fibre lengths as a function of postural sway. The simulations confirmed previous conjectures that reciprocal inhibition is possibly contributing to this effect, but

  15. Spinal mechanisms may provide a combination of intermittent and continuous control of human posture: predictions from a biologically based neuromusculoskeletal model.

    Science.gov (United States)

    Elias, Leonardo Abdala; Watanabe, Renato Naville; Kohn, André Fabio

    2014-11-01

    Several models have been employed to study human postural control during upright quiet stance. Most have adopted an inverted pendulum approximation to the standing human and theoretical models to account for the neural feedback necessary to keep balance. The present study adds to the previous efforts in focusing more closely on modelling the physiological mechanisms of important elements associated with the control of human posture. This paper studies neuromuscular mechanisms behind upright stance control by means of a biologically based large-scale neuromusculoskeletal (NMS) model. It encompasses: i) conductance-based spinal neuron models (motor neurons and interneurons); ii) muscle proprioceptor models (spindle and Golgi tendon organ) providing sensory afferent feedback; iii) Hill-type muscle models of the leg plantar and dorsiflexors; and iv) an inverted pendulum model for the body biomechanics during upright stance. The motor neuron pools are driven by stochastic spike trains. Simulation results showed that the neuromechanical outputs generated by the NMS model resemble experimental data from subjects standing on a stable surface. Interesting findings were that: i) an intermittent pattern of muscle activation emerged from this posture control model for two of the leg muscles (Medial and Lateral Gastrocnemius); and ii) the Soleus muscle was mostly activated in a continuous manner. These results suggest that the spinal cord anatomy and neurophysiology (e.g., motor unit types, synaptic connectivities, ordered recruitment), along with the modulation of afferent activity, may account for the mixture of intermittent and continuous control that has been a subject of debate in recent studies on postural control. Another finding was the occurrence of the so-called "paradoxical" behaviour of muscle fibre lengths as a function of postural sway. The simulations confirmed previous conjectures that reciprocal inhibition is possibly contributing to this effect, but on the

  16. The Mechanics and Trajectory Control in Locust Jumping

    Institute of Scientific and Technical Information of China (English)

    Longbao Han; Zhouyi Wang; Aihong Ji; Zhendong Dai

    2013-01-01

    Locusts (Locusta migratoria manilensis) are characterised by their flying ability and abiding jump ability.Research on the jumping mechanics and behavior of locusts plays an important role in elucidating the mechanism of hexapod locomotion.The jump gestures of locusts were observed using high-speed video camera at 250 fps.The reaction forces of the hindlegs were measured using two three-dimensional sensors,in case the two hindlegs attached on separated sensor plates.The jump gestures and reaction forces were used to illustrate the locust jumping mechanism.Results show that the trajectory control is achieved by rapid rolling and yawing movements of the locust body,caused by the forelegs,midlegs and hindlegs in different jumping phases.The final jump trajectory was not determined until hind tarsi left platform.The horizontal co-impulse between two hindlegs might play a key role in jump stability and accuracy.Besides,the angle between two hindlegs affects the control of jump trajectory but has a little effect on the elevation angle of a jump,which is controlled mechanically by the initial position of the hindlegs.This research lays the groundwork for the probable design and development of biomimetic robotics.

  17. Flow around a semicircular cylinder with passive flow control mechanisms

    Science.gov (United States)

    Hamed, A. M.; Vega, J.; Liu, B.; Chamorro, L. P.

    2017-03-01

    Wind tunnel experiments were performed to study the effect of passive flow control strategies on the wake and drag of a semicircular cylinder of infinite aspect ratio. High-resolution planar particle image velocimetry was used to obtain flow statistics around the semicircular cylinder at Reynolds number Re≈ 3.2× 10^4 based on the cylinder diameter. The control mechanisms under consideration include rigid flaps of various lengths placed at the edges of the structure and a small slot along the symmetry plane of the cylinder. Mean velocity fields reveal the distinctive effects of each passive mechanism on the flow, such as velocity recovery, size of the recirculation bubble and location of the reattachment point. The distributions of turbulence kinetic energy and kinematic shear stress show the modulation of each passive control mechanism on the wake, including the onset and location of the maximum turbulence levels. Instantaneous and mean fields of swirling strength further highlight the role of the passive mechanisms in the vortex dynamics. Drag coefficient for the various cases was estimated indirectly from the flow measurements using a momentum balance. This approach shows that long flaps and slot were able to reduce drag with respect to the base case. The rigid flaps with length coincident with the diameter of the cylinder offered the best performance with drag reduction of ˜25%.

  18. Adaptive mechanism-based congestion control for networked systems

    Science.gov (United States)

    Liu, Zhi; Zhang, Yun; Chen, C. L. Philip

    2013-03-01

    In order to assure the communication quality in network systems with heavy traffic and limited bandwidth, a new ATRED (adaptive thresholds random early detection) congestion control algorithm is proposed for the congestion avoidance and resource management of network systems. Different to the traditional AQM (active queue management) algorithms, the control parameters of ATRED are not configured statically, but dynamically adjusted by the adaptive mechanism. By integrating with the adaptive strategy, ATRED alleviates the tuning difficulty of RED (random early detection) and shows a better control on the queue management, and achieve a more robust performance than RED under varying network conditions. Furthermore, a dynamic transmission control protocol-AQM control system using ATRED controller is introduced for the systematic analysis. It is proved that the stability of the network system can be guaranteed when the adaptive mechanism is finely designed. Simulation studies show the proposed ATRED algorithm achieves a good performance in varying network environments, which is superior to the RED and Gentle-RED algorithm, and providing more reliable service under varying network conditions.

  19. The Dark Energy Spectroscopic Instrument (DESI) instrument mechanism control systems

    Science.gov (United States)

    Coker, Carl T.; Pappalardo, Daniel; Pogge, Richard; Martini, Paul; Derwent, Mark; O'Brien, Thomas P.; Honscheid, Klaus

    2016-08-01

    The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 40 million galaxies over 14,000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5,000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We present the design details of the instrument mechanism control systems for the spectrographs. Each spectrograph has a stand-alone mechanism control box that operates the unit's four remotely-operated mechanisms (two shutters and two Hartmannn doors), and provides a suite of temperature and humidity sensors. Each control box is highly modular, and is operated by a dedicated on-board Linux computer to provide all of the control and monitoring functions. We describe our solution for integrating a number of network-connected devices within each unit spectrograph, and describe the basic software architecture.

  20. Effects of sugammadex on incidence of postoperative residual neuromuscular blockade

    DEFF Research Database (Denmark)

    Brueckmann, B; Sasaki, N; Grobara, P;

    2015-01-01

    by randomized allocation to sugammadex (2 or 4 mg kg(-1)) or usual care (neostigmine/glycopyrrolate, dosing per usual care practice) for reversal of neuromuscular blockade. Timing of reversal agent administration was based on the providers' clinical judgement. Primary endpoint was the presence of residual......BACKGROUND: This study aimed to investigate whether reversal of rocuronium-induced neuromuscular blockade with sugammadex reduced the incidence of residual blockade and facilitated operating room discharge readiness. METHODS: Adult patients undergoing abdominal surgery received rocuronium, followed...... neuromuscular blockade at PACU admission, defined as a train-of-four (TOF) ratio

  1. Neuromuscular ultrasound findings in polyneuropathy secondary to disulfiram.

    Science.gov (United States)

    Stone, Sarah L; Cartwright, Michael S; Panea, Oana R; Vann, Ryan C; Magruder, John L; Walker, Francis O

    2014-12-01

    Disulfiram toxicity can cause multiple neurologic problems, including a reversible distal sensorimotor axonal polyneuropathy. Although electrodiagnosis and biopsy results have been described in the diagnosis and management of patients with disulfiram associated polyneuropathy, neuromuscular ultrasound findings have not been reported. The authors present a case of electrodiagnostically confirmed axonal polyneuropathy with relative sural sparing secondary to disulfiram and describe the neuromuscular ultrasound findings in this individual. Ultrasound demonstrated distal enlargement with slight side-to-side asymmetry and normal proximal cross-sectional area in the lower extremity nerves. Neuromuscular ultrasound is another diagnostic modality that may be used to assist in the diagnosis of patients with polyneuropathy secondary to disulfiram.

  2. A Markov computer simulation model of the economics of neuromuscular blockade in patients with acute respiratory distress syndrome

    Directory of Open Access Journals (Sweden)

    Chow John L

    2006-03-01

    Full Text Available Abstract Background Management of acute respiratory distress syndrome (ARDS in the intensive care unit (ICU is clinically challenging and costly. Neuromuscular blocking agents may facilitate mechanical ventilation and improve oxygenation, but may result in prolonged recovery of neuromuscular function and acute quadriplegic myopathy syndrome (AQMS. The goal of this study was to address a hypothetical question via computer modeling: Would a reduction in intubation time of 6 hours and/or a reduction in the incidence of AQMS from 25% to 21%, provide enough benefit to justify a drug with an additional expenditure of $267 (the difference in acquisition cost between a generic and brand name neuromuscular blocker? Methods The base case was a 55 year-old man in the ICU with ARDS who receives neuromuscular blockade for 3.5 days. A Markov model was designed with hypothetical patients in 1 of 6 mutually exclusive health states: ICU-intubated, ICU-extubated, hospital ward, long-term care, home, or death, over a period of 6 months. The net monetary benefit was computed. Results Our computer simulation modeling predicted the mean cost for ARDS patients receiving standard care for 6 months to be $62,238 (5% – 95% percentiles $42,259 – $83,766, with an overall 6-month mortality of 39%. Assuming a ceiling ratio of $35,000, even if a drug (that cost $267 more hypothetically reduced AQMS from 25% to 21% and decreased intubation time by 6 hours, the net monetary benefit would only equal $137. Conclusion ARDS patients receiving a neuromuscular blocker have a high mortality, and unpredictable outcome, which results in large variability in costs per case. If a patient dies, there is no benefit to any drug that reduces ventilation time or AQMS incidence. A prospective, randomized pharmacoeconomic study of neuromuscular blockers in the ICU to asses AQMS or intubation times is impractical because of the highly variable clinical course of patients with ARDS.

  3. Visual and tactile assessment of neuromuscular fade.

    Science.gov (United States)

    Brull, S J; Silverman, D G

    1993-08-01

    The accuracy of visual and tactile assessment of the neuromuscular fade in response to train-of-four (TOF) and double-burst stimulation (DBS) were compared to assess their relative utility in the clinical setting. For each of 74 data sets with a mechanographic TOF ratio less than 0.70, an observer (blinded to the presence or degree of fade) performed visual and tactile assessments of fade in response to TOF, DBS3,3, and DBS3,2 stimuli at low current (20 and 30 mA) and high current (50 and 60 mA). For the range of mechanographic TOF ratios between 0.41 and 0.70, visual assessment failed to identify TOF, DBS3,3, and DBS3,2 fade in 46%, 18%, and 14% of cases at high current and in 23%, 5%, and 0% of cases at low current, respectively. Tactile assessments failed to identify fade in 55%, 23%, and 14% of cases at high current and in 23%, 14%, and 14% of cases at low current. Overall, the ability to detect fade was comparable for visual and tactile assessments regardless of the method of neurostimulation (P = NS with paired t-test). However, the degree of overestimation of the fade ratio (i.e., quantitative assessment) tended to be less when using tactile means; the difference achieved significance for TOF at low current and DBS3,3 at both low and high currents. We conclude that the differences between the visual and tactile means of assessment are relatively small compared to the differences among the TOF and DBS patterns of neurostimulation. Both subjective techniques are often inadequate in settings in which assurance of full recovery of neuromuscular function is critical.

  4. Comparative Study on New AQM Mechanisms for Congestion Control

    Directory of Open Access Journals (Sweden)

    Ramakrishna B B

    2013-09-01

    Full Text Available As usage of network goes increasing day by day, managing network traffic becomes a very difficult task. It is important to avoid high packet loss rates in the Internet. Congestion is the one of the major issue in the present networks. Congestion Control is one of the solutions adopted to solve the congestion issue and to control it. Numbers of queue management algorithms are proposed for congestion control and to reduce high packet loss rates. Active Queue Management (AQM is one such mechanism which provides better control over congestion. In this paper a study is made on recent load based AQM techniques that are proposed and its merits and shortfall is presented.

  5. Biomimetic Control of Mechanical Systems Equipped with Musculotendon Actuators

    Institute of Scientific and Technical Information of China (English)

    Javier Moreno-Valenzuela; Adriana Salinas-Avila

    2011-01-01

    This paper addresses the problem of modelling, control, and simulation of a mechanical system actuated by an agonist-antagonist musculotendon subsystem. Contraction dynamics is given by case I of Zajac's model. Saturated semi positive proportional-derivative-type controllers with switching as neural excitation inputs are proposed. Stability theory of switched system and SOSTOOLS, which is a sum of squares optimization toolbox of Matlab, are used to determine the stability of the obtained closed-loop system. To corroborate the obtained theoretical results numerical simulations are carried out. As additional contribution, the discussed ideas are applied to the biomimetic control of a DC motor, i.e., the position control is addressed assuming the presence of musculotendon actuators. Real-experiments corroborate the expected results.

  6. Controlling chaos based on an adaptive nonlinear compensator mechanism

    Institute of Scientific and Technical Information of China (English)

    Tian Ling-Ling; Li Dong-Hai; Sun Xian-Fang

    2008-01-01

    The control problems of chaotic systems are investigated in the presence of parametric uncertainty and persistent external disturbances based on nonlinear control theory.By using a designed nonlinear compensator mechanism,the system deterministic nonlinearity,parametric uncertainty and disturbance effect can be compensated effectively.The renowned chaotic Lorenz system subjected to parametric variations and external disturbances is studied as an illustrative example.From the Lyapunov stability theory,sufficient conditions for choosing control parameters to guarantee chaos control are derived.Several experiments are carried out,including parameter change experiments,set-point change experiments and disturbance experiments.Simulation results indicate that the chaotic motion can be regulated not only to steady states but also to any desired periodic orbits with great immunity to parametric variations and external disturbances.

  7. Enhancement of Neuromuscular Activity by Natural Specimens and Cultured Mycelia of Cordyceps sinensis in Mice

    Science.gov (United States)

    Singh, K. P.; Meena, H. S.; Negi, P. S.

    2014-01-01

    The present study was aimed to evaluate the effect of natural specimen and laboratory cultured mycelia of Cordyceps sinensis on neuromuscular activity in mice. The powder of natural specimen and laboratory cultured Cordyceps sinensis was orally administered at the dose rate of 100, 300 and 500 mg/kg for 30 days. Natural specimen and in vitro propagated Cordyceps sinensis showed significant (P<0.05) enhancement in neuromuscular endurance and antidepressant activity at 300 and 500 mg/kg as compared to the control group. However, the fungus did not proved to be as effective as fluoxetine in exhibiting antidepressant action. Muscular endurance was determined on a Rota rod apparatus while antidepressant (mood elevating) activity was measured on a photoactometer in Swiss albino mice. The effects produced by both natural specimens and laboratory cultured Cordyceps sinensis were comparable and showed almost equal potency. PMID:25425763

  8. Reactive Neuromuscular Training: A Multi-level Approach to Rehabilitation of the Unstable Shoulder.

    Science.gov (United States)

    Guido, John A; Stemm, John

    2007-05-01

    In this clinical commentary, the use of reactive neuromuscular training (RNT) will be discussed as part of an overall functional rehabilitation program in the treatment of the unstable glenohumeral joint. The RNT program is designed to restore the synchrony and synergy of muscle firing patterns about the shoulder, which are required for dynamic joint stability and fine motor control. Reactive neuromuscular training allows the clinician to bridge the gap between the achievement of clinical based goals and a return to athletic competition. The possible effects of RNT on central nervous system (CNS) programming to establish appropriate reflex responses and functional stability at the glenohumeral joint will be explored. The issues reviewed in this article will highlight the need for future research in this area.

  9. Neuromuscular exercise improves functional performance in patients with severe hip osteoarthritis

    DEFF Research Database (Denmark)

    Villadsen, Allan; Overgaard, Søren; Larsen, Anders Holsgaard

    . Randomized controlled trial (Clinicaltrials.gov identifier: NCT01003756). 84 patients, 51% female, mean age 68.6±7.8 years, BMI 28.7±4.7 scheduled for total hip replacement at Svendborg Community Hospital, Odense University Hospital, Denmark were included. Intervention. Participants were randomized...... to an eight-week neuromuscular exercise (NEMEX-TJR) intervention or care-as-usual (verbal and written preoperative information). Intervention was supervised and offered twice a week with each session lasting one hour. The program is considered feasible and safe in this patient group and previously described......±4 sessions (Table 1). In favor of the intervention group, the between-group difference was significant for 20-m walk (2.2 seconds, p=.009), chair stands (1.7 seconds, p=.022) and leg extension for the non operated leg (.17 W/kg, p=.049) (Table 2). Conclusion. Eight weeks neuromuscular exercise according...

  10. Quality control of injection moulded micro mechanical parts

    DEFF Research Database (Denmark)

    Gasparin, Stefania; Tosello, Guido; Hansen, Hans Nørgaard

    2009-01-01

    Quality control of micro components is an increasing challenge. Smaller mechanical parts are characterized by smaller tolerance to be verified. This paper focuses on the dimensional verification of micro injection moulded components selected from an industrial application. These parts are measured...... using an Optical Coordinate Measuring Machine (OCMM), which guarantees fast surface scans suitable for in line quality control. The uncertainty assessment of the measurements is calculated following the substitution method. To investigate the influence parameters in optical coordinate metrology two...... analyses are carried out and discussed. The estimation of the total variability of optical measurements and instrument repeatability are reported....

  11. Optimal control of underactuated mechanical systems: A geometric approach

    Science.gov (United States)

    Colombo, Leonardo; Martín De Diego, David; Zuccalli, Marcela

    2010-08-01

    In this paper, we consider a geometric formalism for optimal control of underactuated mechanical systems. Our techniques are an adaptation of the classical Skinner and Rusk approach for the case of Lagrangian dynamics with higher-order constraints. We study a regular case where it is possible to establish a symplectic framework and, as a consequence, to obtain a unique vector field determining the dynamics of the optimal control problem. These developments will allow us to develop a new class of geometric integrators based on discrete variational calculus.

  12. Optimal Control of Underactuated Mechanical Systems: A Geometric Approach

    CERN Document Server

    Colombo, L; Zuccalli, M

    2009-01-01

    In this paper, we consider a geometric formalism for optimal control of underactuated mechanical systems. Our techniques are an adaptation of the classical Skinner and Rusk approach for the case of Lagrangian dynamics with higher-order constraints. We study a regular case where it is possible to establish a symplectic framework and, as a consequence, to obtain a unique vector field determining the dynamics of the optimal control problem. These developments will allow us to develop a new class of geometric integrators based on discrete variational calculus.

  13. Neuromuscular electrical stimulation of the median nerve facilitates low motor cortex excitability in patients with spinocerebellar ataxia.

    Science.gov (United States)

    Chen, Chih-Chung; Chuang, Yu-Fen; Yang, Hsiao-Chu; Hsu, Miao-Ju; Huang, Ying-Zu; Chang, Ya-Ju

    2015-02-01

    The neuromodulation of motor excitability has been shown to improve functional movement in people with central nervous system damage. This study aimed to investigate the mechanism of peripheral neuromuscular electrical stimulation (NMES) in motor excitability and its effects in people with spinocerebellar ataxia (SCA). This single-blind case-control study was conducted on young control (n=9), age-matched control (n=9), and SCA participants (n=9; 7 SCAIII and 2 sporadic). All participants received an accumulated 30 min of NMES (25 Hz, 800 ms on/800 ms off) of the median nerve. The central motor excitability, measured by motor evoked potential (MEP) and silent period, and the peripheral motor excitability, measured by the H-reflex and M-wave, were recorded in flexor carpi radialis (FCR) muscle before, during, and after the NMES was applied. The results showed that NMES significantly enhanced the MEP in all 3 groups. The silent period, H-reflex and maximum M-wave were not changed by NMES. We conclude that NMES enhances low motor excitability in patients with SCA and that the mechanism of the neuromodulation was supra-segmental. These findings are potentially relevant to the utilization of NMES for preparation of motor excitability. The protocol was registered at Clinicaltrials.gov (NCT02103075).

  14. Antenna mechanism of length control of actin cables

    CERN Document Server

    Mohapatra, Lishibanya; Kondev, Jane

    2014-01-01

    Actin cables are linear cytoskeletal structures that serve as tracks for myosin-based intracellular transport of vesicles and organelles in both yeast and mammalian cells. In a yeast cell undergoing budding, cables are in constant dynamic turnover yet some cables grow from the bud neck toward the back of the mother cell until their length roughly equals the diameter of the mother cell. This raises the question: how is the length of these cables controlled? Here we describe a novel molecular mechanism for cable length control inspired by recent experimental observations in cells. This antenna mechanism involves three key proteins: formins, which polymerize actin, Smy1 proteins, which bind formins and inhibit actin polymerization, and myosin motors, which deliver Smy1 to formins, leading to a length-dependent actin polymerization rate. We compute the probability distribution of cable lengths as a function of several experimentally tuneable parameters such as the formin-binding affinity of Smy1 and the concentra...

  15. Mechanization and Control Concepts for Biologically Inspired Micro Aerial Vehicles

    Science.gov (United States)

    Raney, David L.; Slominski, Eric C.

    2003-01-01

    It is possible that MAV designs of the future will exploit flapping flight in order to perform missions that require extreme agility, such as rapid flight beneath a forest canopy or within the confines of a building. Many of nature's most agile flyers generate flapping motions through resonant excitation of an aeroelastically tailored structure: muscle tissue is used to excite a vibratory mode of their flexible wing structure that creates propulsion and lift. A number of MAV concepts have been proposed that would operate in a similar fashion. This paper describes an ongoing research activity in which mechanization and control concepts with application to resonant flapping MAVs are being explored. Structural approaches, mechanical design, sensing and wingbeat control concepts inspired by hummingbirds, bats and insects are examined. Experimental results from a testbed capable of generating vibratory wingbeat patterns that approximately match those exhibited by hummingbirds in hover, cruise, and reverse flight are presented.

  16. A Dynamic Adaptive Layered Multicast Congestion Control Mechanism

    Institute of Scientific and Technical Information of China (English)

    REN Liyong; LU Xianliang; WEI Qingsong; ZHOU Xu

    2003-01-01

    To solve the problem that most of existing layered multicast protocols cannot adapt to dynamic network conditions because their layers are coarsely granulated and static, a new congestion control mechanism for dynamic adaptive layered multicast(DALM) is presented. In this mechanism, a novel feedback aggregating algorithm is put forward, which can dynamically determine the number of layers and the rate of each layer, and can efficiently improve network bandwidth utilization ratio.Additionally, because all layers is transmitted in only one group, the intricate and time-consuming internet group management protocol(IGMP) operations, caused by receiver joining a new layer or leaving the topmost subscribed layer, are thoroughly eliminated. And this mechanism also avoids other problems resulted from multiple groups. Simulation results show that DALM is adaptive and TCP friendly.

  17. Invasive mechanism and control strategy of Ageratina adenophora (Sprengel)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation,the formation of single dominant population, displacement of native plants and sustainable management strategies were investigated. The present results helped to clarify and explain such issues as the adaptability post invasion,interaction and competition between inter-and intra-species and community resistance, thereby providing important references to researches on other invasive alien species.

  18. Immunosensor with Fluid Control Mechanism for Salivary Cortisol Analysis

    OpenAIRE

    Yamaguchi, Masaki; Matsuda, Yohei; Sasaki, Shohei; Sasaki, Makoto; Kadoma, Yoshihiro; Imai, Yoshikatsu; Niwa, Daisuke; Shetty, Vivek

    2012-01-01

    The purpose of this research is to demonstrate a new design for a cortisol immunosensor for the noninvasive and quantitative analysis of salivary cortisol. We propose a cortisol immunosensor with a fluid control mechanism which has both a vertical flow and a lateral flow. The detected current resulting from a competitive reaction between the sample cortisol and a glucose oxidase (GOD)-labeled cortisol conjugate was found to be inversely related to the concentration of cortisol in the sample s...

  19. Mechanisms of control of microRNA biogenesis

    OpenAIRE

    Davis-Dusenbery, Brandi N.; Hata, Akiko

    2010-01-01

    MicroRNAs (miRNAs) are a class of ∼22 nt non-coding RNAs that control diverse biological functions in animals, plants and unicellular eukaryotes by promoting degradation or inhibition of translation of target mRNAs. miRNA expression is often tissue specific and developmentally regulated. Aberrant expression of miRNAs has been linked to developmental abnormalities and human diseases, including cancer and cardiovascular disorders. The recent identification of mechanisms of miRNA biogenesis regu...

  20. Multi-finger prehension: control of a redundant mechanical system.

    Science.gov (United States)

    Latash, Mark L; Zatsiorsky, Vladimir M

    2009-01-01

    The human hand has been a fascinating object of study for researchers in both biomechanics and motor control. Studies of human prehension have contributed significantly to the progress in addressing the famous problem of motor redundancy. After a brief review of the hand mechanics, we present results of recent studies that support a general view that the apparently redundant design of the hand is not a source of computational problems but a rich apparatus that allows performing a variety of tasks in a reliable and flexible way (the principle of abundance). Multi-digit synergies have been analyzed at two levels of a hypothetical hierarchy involved in the control of prehensile actions. At the upper level, forces and moments produced by the thumb and virtual finger (an imagined finger with a mechanical action equal to the combined mechanical action of all four fingers of the hand) co-vary to stabilize the gripping action and the orientation of the hand-held object. These results support the principle of superposition suggested earlier in robotics with respect to the control of artificial grippers. At the lower level of the hierarchy, forces and moments produced by individual fingers co-vary to stabilize the magnitude and direction of the force vector and the moment of force produced by the virtual finger. Adjustments to changes in task constraints (such as, for example, friction under individual digits) may be local and synergic. The latter reflect multi-digit prehension synergies and may be analyzed with the so-called chain effects: Sequences of relatively straightforward cause-effect links directly related to mechanical constraints leading to non-trivial strong co-variation between pairs of elemental variables. Analysis of grip force adjustments during motion of hand-held objects suggests that the central nervous system adjusts to gravitational and inertial loads differently. The human hand is a gold mine for researchers interested in the control of natural human

  1. CONFIGURATION CONTROLLABILITY FOR NON-ZERO POTENTIAL MECHANICAL CONTROL SYSTEMS WITH DISSIPATION

    Institute of Scientific and Technical Information of China (English)

    KANG Jian-ling; WANG Hong; YE Hua-wen

    2005-01-01

    Within the affine connection framework of Lagrangian control systems, based on the results of Sussmann on controllability of general affine control systems defined on a finite-dimensional manifold, a computable sufficient condition of configuration controllability for the simple mechanical control systems was extended to the case of systems with strictly dissipative energy terms of linear isotropic nature, and a sufficient condition of equilibrium controllability for the systems was also given, where Lagrangian is kinetic energy minus potential energy. Lie bracketting of vector fields in controllable Lie algebra, and the symmetric product associated with Levi-Civita connection show virtues in the discussion. Liouville vector field simplified the computation of controllable Lie algebra for the systems, although the terms of potential energy complicated the study of configuration controllability.

  2. Control of directional change after mechanical stimulation in Drosophila

    Directory of Open Access Journals (Sweden)

    Zhou Yating

    2012-10-01

    Full Text Available Abstract Background Proper adjustment of moving direction after external mechanical stimulation is essential for animals to avoid danger (e.g. predators, and thus is vital for survival. This process involves sensory inputs, central processing and motor outputs. Recent studies have made considerable progress in identifying mechanosensitive neurons and mechanosensation receptor proteins. Our understandings of molecular and cellular mechanisms that link mechanosensation with the changes in moving direction, however, remain limited. Results In this study, we investigate the control of movement adjustment in Drosophila. In response to gentle touch at the anterior segments, Drosophila larvae reorient and select a new direction for forward movement. The extent of change in moving direction is correlated with the intensity of tactile stimuli. Sensation of gentle touch requires chordotonal organs and class IV da neurons. Genetic analysis indicates an important role for the evolutionarily conserved immunoglobulin (Ig superfamily protein Turtle (Tutl to regulate touch-initiated directional change. Tutl is required specifically in post-mitotic neurons at larval stage after the completion of embryonic development. Circuit breaking analysis identified a small subset of Tutl-positive neurons that are involved in the adjustment of moving direction. Conclusion We identify Tutl and a small subset of CNS neurons in modulating directional change in response to gentle touch. This study presents an excellent starting point for further dissection of molecular and cellular mechanisms controlling directional adjustment after mechanical stimulation.

  3. Mechanical design and optimal control of humanoid robot (TPinokio

    Directory of Open Access Journals (Sweden)

    Teck Chew Wee

    2014-04-01

    Full Text Available The mechanical structure and the control of the locomotion of bipedal humanoid is an important and challenging domain of research in bipedal robots. Accurate models of the kinematics and dynamics of the robot are essential to achieve bipedal locomotion. Toe-foot walking produces a more natural and faster walking speed and it is even possible to perform stretch knee walking. This study presents the mechanical design of a toe-feet bipedal, TPinokio and the implementation of some optimal walking gait generation methods. The optimality in the gait trajectory is achieved by applying augmented model predictive control method and the pole-zero cancellation method, taken into consideration of a trade-off between walking speed and stability. The mechanism of the TPinokio robot is designed in modular form, so that its kinematics can be modelled accurately into a multiple point-mass system, its dynamics is modelled using the single and double mass inverted pendulum model and zero-moment-point concept. The effectiveness of the design and control technique is validated by simulation testing with the robot walking on flat surface and climbing stairs.

  4. Antenna Mechanism of Length Control of Actin Cables.

    Directory of Open Access Journals (Sweden)

    Lishibanya Mohapatra

    2015-06-01

    Full Text Available Actin cables are linear cytoskeletal structures that serve as tracks for myosin-based intracellular transport of vesicles and organelles in both yeast and mammalian cells. In a yeast cell undergoing budding, cables are in constant dynamic turnover yet some cables grow from the bud neck toward the back of the mother cell until their length roughly equals the diameter of the mother cell. This raises the question: how is the length of these cables controlled? Here we describe a novel molecular mechanism for cable length control inspired by recent experimental observations in cells. This "antenna mechanism" involves three key proteins: formins, which polymerize actin, Smy1 proteins, which bind formins and inhibit actin polymerization, and myosin motors, which deliver Smy1 to formins, leading to a length-dependent actin polymerization rate. We compute the probability distribution of cable lengths as a function of several experimentally tuneable parameters such as the formin-binding affinity of Smy1 and the concentration of myosin motors delivering Smy1. These results provide testable predictions of the antenna mechanism of actin-cable length control.

  5. Neuromuscular fatigue after maximal exercise in patients with cystic fibrosis.

    Science.gov (United States)

    Vallier, J M; Gruet, M; Mely, L; Pensini, M; Brisswalter, J

    2011-04-01

    The aim of this study was to determine whether patients with cystic fibrosis (CF), despite their ventilatory limitation, would develop neuromuscular fatigue of quadriceps muscles following a maximal cycling exercise. Eleven adults with CF (age=26.8±6.9years; forced expiratory volume in 1s=54.1±12.8% predicted) and 11 age-matched healthy subjects performed a maximal incremental cycle test with respiratory gas exchange measurements. Maximal voluntary contraction (MVC) and electromyographic (EMG) activity of the vastus medialis muscle were recorded before and after exercise. Neural and contractile properties of the quadriceps were also investigated using femoral nerve electrical stimulation. Patients had lower exercise capacity, peak oxygen uptake and MVC than controls. MVC fell significantly postexercise in both groups (CF: -20±10%, controls: -19±6%; ppattern (-38.4±14.4%, -42.1±14.7% and -15±20.4%) but the statistical significance was not reached for the maximal rate of twitch torque relaxation. In conclusion, CF patients demonstrated lower limb fatigue following symptom-limited cycle exercise, which was comparable to that exhibited by healthy controls. This fatigue may be due to contractile impairments and not to transmission failure. Further studies should be conducted in a larger sample to confirm these preliminary results.

  6. Effect of nimodipine and flunarizine on neuromuscular function in mice

    Directory of Open Access Journals (Sweden)

    Swapnil B. Kaikade

    2016-08-01

    Conclusions: Nimodipine has significant dose dependent depressant action on neuromuscular function while flunarizine has no effect on the above mentioned parameter. [Int J Basic Clin Pharmacol 2016; 5(4.000: 1524-1527

  7. Exploring employment in consultation reports of patients with neuromuscular diseases

    NARCIS (Netherlands)

    Heerkens, Yvonne; Kuyk-Minis, Marie Antoinette van; Cup, Edith; Engels, Josephine; Engelen, Baziel van; Oostendorp, Rob

    2012-01-01

    To explore consultation reports for patient and employment characteristics and recommendations on employment regarding patients with neuromuscular diseases (NMDs). Eighty percent of the included consultation reports contained information on employment. Less than half the patients with NMD were emplo

  8. Genetics of Pediatric-Onset Motor Neuron and Neuromuscular Diseases

    Science.gov (United States)

    2015-08-24

    Spinal Muscular Atrophy; Charcot-Marie-Tooth Disease; Muscular Dystrophy; Spinal Muscular Atrophy With Respiratory Distress 1; Amyotrophic Lateral Sclerosis; Motor Neuron Disease; Neuromuscular Disease; Peroneal Muscular Atrophy; Fragile X Syndrome

  9. The potential of disease management for neuromuscular hereditary disorders.

    Science.gov (United States)

    Chouinard, Maud-Christine; Gagnon, Cynthia; Laberge, Luc; Tremblay, Carmen; Côté, Charlotte; Leclerc, Nadine; Mathieu, Jean

    2009-01-01

    Neuromuscular hereditary disorders require long-term multidisciplinary rehabilitation management. Although the need for coordinated healthcare management has long been recognized, most neuromuscular disorders are still lacking clinical guidelines about their long-term management and structured evaluation plan with associated services. One of the most prevalent adult-onset neuromuscular disorders, myotonic dystrophy type 1, generally presents several comorbidities and a variable clinical picture, making management a constant challenge. This article presents a healthcare follow-up plan and proposes a nursing case management within a disease management program as an innovative and promising approach. This disease management program and model consists of eight components including population identification processes, evidence-based practice guidelines, collaborative practice, patient self-management education, and process outcomes evaluation (Disease Management Association of America, 2004). It is believed to have the potential to significantly improve healthcare management for neuromuscular hereditary disorders and will prove useful to nurses delivering and organizing services for this population.

  10. Bio-Inspired Controller for a Robot Cheetah with a Neural Mechanism Controlling Leg Muscles

    Institute of Scientific and Technical Information of China (English)

    Xin Wang; Mantian Li; Pengfei Wang; Wei Guo; Lining Sun

    2012-01-01

    The realization of a high-speed running robot is one of the most challenging problems in developing legged robots.The excellent performance of cheetahs provides inspiration for the control and mechanical design of such robots.This paper presents a three-dimensional model of a cheetah that predicts the locomotory behaviors of a running cheetah.Applying biological knowledge of the neural mechanism,we control the muscle flexion and extension during the stance phase,and control the positions of the joints in the flight phase via a PD controller to minimize complexity.The proposed control strategy is shown to achieve similar locomotion of a real cheetah.The simulation realizes good biological properties,such as the leg retraction,ground reaction force,and spring-like leg behavior.The stable bounding results show the promise of the controller in high-speed locomotion.The model can reach 2.7 m·s- 1 as the highest speed,and can accelerate from 0 to 1.5 m·s -1 in one stride cycle.A mechanical structure based on this simulation is designed to demonstrate the control approach,and the most recently developed hindlimb controlled by the proposed controller is presented in swinging-leg experiments and jump-force experiments.

  11. Dynamics and control of mechanical systems in offshore engineering

    CERN Document Server

    He, Wei; How, Bernard Voon Ee; Choo, Yoo Sang

    2014-01-01

    Dynamics and Control of Mechanical Systems in Offshore Engineering is a comprehensive treatment of marine mechanical systems (MMS) involved in processes of great importance such as oil drilling and mineral recovery. Ranging from nonlinear dynamic modeling and stability analysis of flexible riser systems, through advanced control design for an installation system with a single rigid payload attached by thrusters, to robust adaptive control for mooring systems, it is an authoritative reference on the dynamics and control of MMS. Readers will gain not only a complete picture of MMS at the system level, but also a better understanding of the technical considerations involved and solutions to problems that commonly arise from dealing with them. The text provides:                                                                                                                                 ...

  12. Acute and subchronic neuromuscular blocking characteristics of streptomycin: a comparison with neomycin.

    Science.gov (United States)

    Lee, C; deSilva, A J

    1979-05-01

    The characteristics of the neuromuscular block produced by streptomycin in vivo were studied on the sciatic-tibialis anterior nerve-muscle preparation of eight anaesthetized cats. The lungs of the animals were ventilated mechanically and normocarbia was maintained. During acute exposure to streptomycin (within 2 h), ED50 for blockade of the twitch was 56 (SEM +/- 5) mg kg-1 of the base. The characteristics of block were similar to those of neomycin-induced block in some aspects. There was absence of train-of-four fade and tetanic fade, partial sparing of the responses elicited at 10 Hz and 20 Hz, and total sparing of the 50 Hz tetanus, as well as the post-tetanic twitch. In contrast to neomycin-induced neuromuscular block, however, post-tetanic exhaustion was not observed and prolonged exposure to streptomycin (22-28 h) did not change the characteristics of the block. We conclude that, despite their chemical similarities, streptomycin and neomycin block neuromuscular transmission differently.

  13. Nonmuscle Myosin II helps regulate synaptic vesicle mobility at the Drosophila neuromuscular junction

    Directory of Open Access Journals (Sweden)

    Qiu Xinping

    2010-03-01

    Full Text Available Abstract Background Although the mechanistic details of the vesicle transport process from the cell body to the nerve terminal are well described, the mechanisms underlying vesicle traffic within nerve terminal boutons is relatively unknown. The actin cytoskeleton has been implicated but exactly how actin or actin-binding proteins participate in vesicle movement is not clear. Results In the present study we have identified Nonmuscle Myosin II as a candidate molecule important for synaptic vesicle traffic within Drosophila larval neuromuscular boutons. Nonmuscle Myosin II was found to be localized at the Drosophila larval neuromuscular junction; genetics and pharmacology combined with the time-lapse imaging technique FRAP were used to reveal a contribution of Nonmuscle Myosin II to synaptic vesicle movement. FRAP analysis showed that vesicle dynamics were highly dependent on the expression level of Nonmuscle Myosin II. Conclusion Our results provide evidence that Nonmuscle Myosin II is present presynaptically, is important for synaptic vesicle mobility and suggests a role for Nonmuscle Myosin II in shuttling vesicles at the Drosophila neuromuscular junction. This work begins to reveal the process by which synaptic vesicles traverse within the bouton.

  14. Moving constraints as stabilizing controls in classical mechanics

    CERN Document Server

    Bressan, A

    2008-01-01

    The paper analyzes a Lagrangian system which is controlled by directly assigning some of the coordinates as functions of time, by means of frictionless constraints. In a natural system of coordinates, the equations of motions contain terms which are linear or quadratic w.r.t.time derivatives of the control functions. After reviewing the basic equations, we explain the significance of the quadratic terms, related to geodesics orthogonal to a given foliation. We then study the problem of stabilization of the system to a given point, by means of oscillating controls. This problem is first reduced to the weak stability for a related convex-valued differential inclusion, then studied by Lyapunov functions methods. In the last sections, we illustrate the results by means of various mechanical examples.

  15. Moving Constraints as Stabilizing Controls in Classical Mechanics

    Science.gov (United States)

    Bressan, Alberto; Rampazzo, Franco

    2010-04-01

    The paper analyzes a Lagrangian system which is controlled by directly assigning some of the coordinates as functions of time, by means of frictionless constraints. In a natural system of coordinates, the equations of motion contain terms which are linear or quadratic with respect to time derivatives of the control functions. After reviewing the basic equations, we explain the significance of the quadratic terms related to geodesics orthogonal to a given foliation. We then study the problem of stabilization of the system to a given point by means of oscillating controls. This problem is first reduced to theweak stability for a related convex-valued differential inclusion, then studied by Lyapunov functions methods. In the last sections, we illustrate the results by means of various mechanical examples.

  16. The sagital balance in idiopatic and neuromuscular scoliosis

    OpenAIRE

    Borges,Paulo Alvim; Ocampos, Guilherme Pereira; Mancuso Filho,José Antonio; Letaif,Olavo Biraghi; Marcon, Raphael Martus; Cristante, Alexandre Fogaça

    2014-01-01

    OBJECTIVES: To describe and compare the distribution of spinopelvic parameters (SPP) in a Brazilian population with idiopathic scoliosis (IS) and neuromuscular scoliosis (NMS), and evaluate the association between pelvic incidence (PI) and lumbar lordosis (LL). METHOD: Medical records investigation was performed. Sagital balance angles were measured in patients with neuromuscular and idiopathic scoliosis. RESULTS: IS sample means (in degrees): PI 55.55; Sacral Slope (SS) 45.35; Pelvic Tilt (P...

  17. Bilingualism modulates dual mechanisms of cognitive control: Evidence from ERPs.

    Science.gov (United States)

    Morales, Julia; Yudes, Carolina; Gómez-Ariza, Carlos J; Bajo, M Teresa

    2015-01-01

    Recent behavioral findings with the AX-Continous Performance Task (AX-CPT; Morales et al., 2013) show that bilinguals only outperform monolinguals under conditions that require the highest adjustment between monitoring (proactive) and inhibitory (reactive) control, which supports the idea that bilingualism modulates the coordination of different control mechanisms. In an ERP experiment we aimed to further investigate the role that bilingualism plays in the dynamic combination of proactive and reactive control in the AX-CPT. Our results strongly indicate that bilingualism facilitates an effective adjustment between both components of cognitive control. First, we replicated previous behavioral results. Second, ERP components indicated that bilingualism influences the conflict monitoring, response inhibition and error monitoring components of control (as indexed by the N2 and P3a elicited by the probe and the error-related negativity following incorrect responses, respectively). Thus, bilinguals exerted higher reactive control than monolinguals but only when they needed to overcome the competing cue-information. These findings join others in suggesting that a better understanding of the cognitive benefits of bilingualism may require consideration of a multi-component perspective.

  18. Safe neuromuscular electrical stimulator designed for the elderly.

    Science.gov (United States)

    Krenn, Matthias; Haller, Michael; Bijak, Manfred; Unger, Ewald; Hofer, Christian; Kern, Helmut; Mayr, Winfried

    2011-03-01

    A stimulator for neuromuscular electrical stimulation (NMES) was designed, especially suiting the requirements of elderly people with reduced cognitive abilities and diminished fine motor skills. The aging of skeletal muscle is characterized by a progressive decline in muscle mass, force, and condition. Muscle training with NMES reduces the degradation process. The discussed system is intended for evoked muscle training of the anterior and posterior thigh. The core of the stimulator is based on a microcontroller with two modular output stages. The system has two charge-balanced biphasic voltage-controlled stimulation channels. Additionally, the evoked myoelectric signal (M-wave) and the myokinematic signal (surface acceleration) are measured. A central controller unit allows using the stimulator as a stand-alone device. To set up the training sequences and to evaluate the compliance data, a personal computer is connected to the stimulator via a universal serial bus. To help elderly people handle the stimulator by themselves, the user interface is kept very simple. For safety reasons, the electrode impedance is monitored during stimulation. A comprehensive compliance management with included measurements of muscle activity and stimulation intensity enables a scientific use of the stimulator in clinical trials.

  19. The role of laminins in the organization and function of neuromuscular junctions.

    Science.gov (United States)

    Rogers, Robert S; Nishimune, Hiroshi

    2017-01-01

    The synapse between motor neurons and skeletal muscle is known as the neuromuscular junction (NMJ). Proper alignment of presynaptic and post-synaptic structures of motor neurons and muscle fibers, respectively, is essential for efficient motor control of skeletal muscles. The synaptic cleft between these two cells is filled with basal lamina. Laminins are heterotrimer extracellular matrix molecules that are key members of the basal lamina. Laminin α4, α5, and β2 chains specifically localize to NMJs, and these laminin isoforms play a critical role in maintenance of NMJs and organization of synaptic vesicle release sites known as active zones. These individual laminin chains exert their role in organizing NMJs by binding to their receptors including integrins, dystroglycan, and voltage-gated calcium channels (VGCCs). Disruption of these laminins or the laminin-receptor interaction occurs in neuromuscular diseases including Pierson syndrome and Lambert-Eaton myasthenic syndrome (LEMS). Interventions to maintain proper level of laminins and their receptor interactions may be insightful in treating neuromuscular diseases and aging related degeneration of NMJs.

  20. Mechanical control of mitotic progression in single animal cells.

    Science.gov (United States)

    Cattin, Cedric J; Düggelin, Marcel; Martinez-Martin, David; Gerber, Christoph; Müller, Daniel J; Stewart, Martin P

    2015-09-08

    Despite the importance of mitotic cell rounding in tissue development and cell proliferation, there remains a paucity of approaches to investigate the mechanical robustness of cell rounding. Here we introduce ion beam-sculpted microcantilevers that enable precise force-feedback-controlled confinement of single cells while characterizing their progression through mitosis. We identify three force regimes according to the cell response: small forces (∼5 nN) that accelerate mitotic progression, intermediate forces where cells resist confinement (50-100 nN), and yield forces (>100 nN) where a significant decline in cell height impinges on microtubule spindle function, thereby inhibiting mitotic progression. Yield forces are coincident with a nonlinear drop in cell height potentiated by persistent blebbing and loss of cortical F-actin homogeneity. Our results suggest that a buildup of actomyosin-dependent cortical tension and intracellular pressure precedes mechanical failure, or herniation, of the cell cortex at the yield force. Thus, we reveal how the mechanical properties of mitotic cells and their response to external forces are linked to mitotic progression under conditions of mechanical confinement.

  1. Design and Control of Nonlinear Mechanical Systems for Minimum Time

    Directory of Open Access Journals (Sweden)

    J.B. Cardoso

    2008-01-01

    Full Text Available This paper presents an integrated methodology for optimal design and control of nonlinear flexible mechanical systems, including minimum time problems. This formulation is implemented in an optimum design code and it is applied to the nonlinear behavior dynamic response. Damping and stiffness characteristics plus control driven forces are considered as decision variables. A conceptual separation between time variant and time invariant design parameters is presented, this way including the design space into the control space and considering the design variables as control variables not depending on time. By using time integrals through all the derivations, design and control problems are unified. In the optimization process we can use both types of variables simultaneously or by interdependent levels. For treating minimum time problems, a unit time interval is mapped onto the original time interval, then treating equally time variant and time invariant problems. The dynamic response and its sensitivity are discretized via space-time finite elements, and may be integrated either by at-once integration or step-by-step. Adjoint system approach is used to calculate the sensitivities.

  2. The Role of Chest Physiotherapy in Prevention of Postextubation Atelectasis in Pediatric Patients with Neuromuscular Diseases

    Directory of Open Access Journals (Sweden)

    Nemat BILAN

    2013-02-01

    Full Text Available How to Cite This Article: Bilan N, Poorshiri B.The Role of Chest Physiotherapy in Prevention of Postextubation Atelectasis in Pediatric Patients with Neuromuscular Diseases. Iran J Child Neurol. 2013 Winter; 7 (1:21-24. ObjectiveThere are controversial findings in the literature on the effects of chest physiotherapy on postextubation lung collapse in pediatric age group. Therefore, we aimed to investigate the efficacy of chest physiotherapy in prevention of postextubation atelectasis in pediatric patients. Materials & Methods In a case-control study from March 2007 to March 2011, two groups of patients (35 patients in each group susceptible to lung collapse were enrolled in the study. The studied patients had neuromuscular diseases such as spinal muscular atrophy, Guillain-Barre syndrome, critical illness polyneuropathy/myopathy, and cerebral palsy. The patients were randomly divided into two groups (case and control; The case group underwent daily chest physiotherapy through vibrator and chest percussion and the control group was under supervision. In the latter group, the underlying disease was treated and the lung collapse was managed, if occurred. Results The frequency of atelectasis was lower in the case group who received prophylactic chest physiotherapy compared to the control group (16.6% vs. 40%. Conclusion Chest physiotherapy as well as appropriate and regular change of position can considerably reduce the rate of pulmonary collapse in pediatric patients.References Jorgensen J, Wei JL, Sykes KJ, Klem SA, Weatherly RA, Bruegger DE, Latz AD, Nicklaus PJ. Incidence of and risk factors for airway complications following endotracheal intubation for bronchiolitis. Otolaryngol Head Neck Surg 2007;137(3:394-9.Flenady VJ, Gray PH. Chest physiotherapy for preventing morbidity in babies being extubated from mechanical ventilation. Cochrane Database Syst Rev 2002;(2:CD000283.Odita JC, Kayyali M, Ammari A. Post-extubation atelectasis in ventilated

  3. Modeling Human Error Mechanism for Soft Control in Advanced Control Rooms (ACRs)

    Energy Technology Data Exchange (ETDEWEB)

    Aljneibi, Hanan Salah Ali [Khalifa Univ., Abu Dhabi (United Arab Emirates); Ha, Jun Su; Kang, Seongkeun; Seong, Poong Hyun [KAIST, Daejeon (Korea, Republic of)

    2015-10-15

    To achieve the switch from conventional analog-based design to digital design in ACRs, a large number of manual operating controls and switches have to be replaced by a few common multi-function devices which is called soft control system. The soft controls in APR-1400 ACRs are classified into safety-grade and non-safety-grade soft controls; each was designed using different and independent input devices in ACRs. The operations using soft controls require operators to perform new tasks which were not necessary in conventional controls such as navigating computerized displays to monitor plant information and control devices. These kinds of computerized displays and soft controls may make operations more convenient but they might cause new types of human error. In this study the human error mechanism during the soft controls is studied and modeled to be used for analysis and enhancement of human performance (or human errors) during NPP operation. The developed model would contribute to a lot of applications to improve human performance (or reduce human errors), HMI designs, and operators' training program in ACRs. The developed model of human error mechanism for the soft control is based on assumptions that a human operator has certain amount of capacity in cognitive resources and if resources required by operating tasks are greater than resources invested by the operator, human error (or poor human performance) is likely to occur (especially in 'slip'); good HMI (Human-machine Interface) design decreases the required resources; operator's skillfulness decreases the required resources; and high vigilance increases the invested resources. In this study the human error mechanism during the soft controls is studied and modeled to be used for analysis and enhancement of human performance (or reduction of human errors) during NPP operation.

  4. Applications of Shape Memory Alloys for Neurology and Neuromuscular Rehabilitation

    Directory of Open Access Journals (Sweden)

    Simone Pittaccio

    2015-05-01

    Full Text Available Shape memory alloys (SMAs are a very promising class of metallic materials that display interesting nonlinear properties, such as pseudoelasticity (PE, shape memory effect (SME and damping capacity, due to high mechanical hysteresis and internal friction. Our group has applied SMA in the field of neuromuscular rehabilitation, designing some new devices based on the mentioned SMA properties: in particular, a new type of orthosis for spastic limb repositioning, which allows residual voluntary movement of the impaired limb and has no predetermined final target position, but follows and supports muscular elongation in a dynamic and compliant way. Considering patients in the sub-acute phase after a neurological lesion, and possibly bedridden, the paper presents a mobiliser for the ankle joint, which is designed exploiting the SME to provide passive exercise to the paretic lower limb. Two different SMA-based applications in the field of neuroscience are then presented, a guide and a limb mobiliser specially designed to be compatible with diagnostic instrumentations that impose rigid constraints in terms of electromagnetic compatibility and noise distortion. Finally, the paper discusses possible uses of these materials in the treatment of movement disorders, such as dystonia or hyperkinesia, where their dynamic characteristics can be advantageous.

  5. Neuromuscular Fatigue after Submaximal Intermittent Contractions in Motorcycle Riders.

    Science.gov (United States)

    Torrado, P; Cabib, C; Morales, M; Valls-Sole, J; Marina, M

    2015-11-01

    Highly repetitive submaximal intermittent contractions of the forearm muscles during periods of 30-50 min partially explain why motorcycle races are so demanding for the neuromuscular system. This study investigated the contribution of central and peripheral mechanisms of fatigue on the exerted and contralateral extensor digitorum communis following an intermittent fatigue protocol (IFP) designed for motorcycle riders. 12 riders performed an IFP, which simulates the braking and throttle handle gesture. We examined the time course of recovery of maximal voluntary contraction (MVC), M-wave, motor evoked potential (MEP) to transcranial magnetic stimuli in relaxed and facilitated condition, and the cortical silent period (CSP) at time windows of 1, 3, 5, 10 and 20 min after the IFP. Whereas MVC, M-wave and MEP decreased, CSP lengthened significantly in the fatigued limb after completion of the IFP. Nevertheless, no differences were observed in the contralateral limb. All neurophysiological parameters reverted to baseline values in less than 20 min, while MVC remained lower in the exercised limb. No cross-over effects were observed in the contralateral non-exercised limb. Our results suggest that local factors are those mainly responsible for the incomplete MVC recovery after an intermittent muscle contraction protocol.

  6. Neuromuscular disorders: genes, genetic counseling and therapeutic trials

    Directory of Open Access Journals (Sweden)

    Mayana Zatz

    Full Text Available Abstract Neuromuscular disorders (NMD are a heterogeneous group of genetic conditions, with autosomal dominant, recessive, or X-linked inheritance. They are characterized by progressive muscle degeneration and weakness. Here, we are presenting our major contributions to the field during the past 30 years. We have mapped and identified several novel genes responsible for NMD. Genotype-phenotype correlations studies enhanced our comprehension on the effect of gene mutations on related proteins and their impact on clinical findings. The search for modifier factors allowed the identification of a novel "protective"; variant which may have important implication on therapeutic developments. Molecular diagnosis was introduced in the 1980s and new technologies have been incorporated since then. Next generation sequencing greatly improved our capacity to identify disease-causing mutations with important benefits for research and prevention through genetic counseling of patients' families. Stem cells researches, from and for patients, have been used as tools to study human genetic diseases mechanisms and for therapies development. The clinical effect of preclinical trials in mice and canine models for muscular dystrophies are under investigation. Finally, the integration of our researches and genetic services with our post-graduation program resulted in a significant output of new geneticists, spreading out this expertise to our large country.

  7. Control of forced vibrations of mechanical structures by an electromagnetic controller with a permanent magnet

    DEFF Research Database (Denmark)

    Stein, George Juraj; Darula, Radoslav; Sorokin, Sergey

    2012-01-01

    A theoretical analysis of an electromagnetic vibration controller is presented. The analyzed device consists of a pot-type iron core with a coil and a permanent magnet as a source of constant magnetic flux. The magnetic circuit is closed by a yoke, excited by an external harmonic mechanical force....... Due to the hysteretic effects in the magnetic material the internal losses influence the overall system’s performance. A mathematical model of the force balance in the oscillatory system is derived in a simplified, linearised form. The electric as well as mechanical system is modelled using lumped......-parameter approach and the actuating principle for control of forced vibration is investigated....

  8. Optimum design of control system in recoil mechanisms

    Directory of Open Access Journals (Sweden)

    J. P. Sirpal

    1959-07-01

    Full Text Available The various parameters in the design of a control system in a conventional type of recoil mechanism have been optimized for minimum weight and the ideal form of velocity space variation during runout has been derived. A theoretical analysis for some of the equipments in service reveals that their actual values are very nearly the same as those given by theory except for the ratio l by di which are lower than those theoretically suggested indicating that wide margins of safety against buckling have been used in their design.

  9. Control of mechanical systems with rolling constraints: Application to dynamic control of mobile robots

    Science.gov (United States)

    Sarkar, Nilanjan; Yun, Xiaoping; Kumar, Vijay

    1994-01-01

    There are many examples of mechanical systems that require rolling contacts between two or more rigid bodies. Rolling contacts engender nonholonomic constraints in an otherwise holonomic system. In this article, we develop a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints. We first present a state space realization of a constrained system. We then discuss the input-output linearization and zero dynamics of the system. This approach is applied to the dynamic control of mobile robots. Two types of control algorithms for mobile robots are investigated: trajectory tracking and path following. In each case, a smooth nonlinear feedback is obtained to achieve asymptotic input-output stability and Lagrange stability of the overall system. Simulation results are presented to demonstrate the effectiveness of the control algorithms and to compare the performane of trajectory-tracking and path-following algorithms.

  10. Effect of Early Physical Activity Programs on Motor Performance and Neuromuscular Development in Infants Born Preterm: A Randomized Clinical Trial

    Science.gov (United States)

    Valizadeh, Leila; Sanaeefar, Mahnaz; Hosseini, Mohammad Bager; Asgari Jafarabadi, Mohammad; Shamili, Aryan

    2017-01-01

    Introduction: Although the survival rate of infants born preterm has increased, the prevalence of developmental problems and motor disorders among this population of infants remains the same. This study investigated the effect of physical activity programs in and out of water on motor performance and neuromuscular development of infants born preterm and had induced immobility by mechanical ventilation. Methods: This study was carried out in Al-Zahra hospital, Tabriz. 76 premature infants were randomly assigned into four groups. One group received daily passive range of motion to all extremities based on the Moyer-Mileur protocol. Hydrotherapy group received exercises for shoulders and pelvic area in water every other day. A combination group received physical activity programs in and out of water on alternating days. Infants in a containment group were held in a fetal position. Duration of study was two weeks ‘from 32 through 33 weeks post menstrual age (PMA). Motor outcomes were measured by the Test of Infant Motor Performance. Neuromuscular developmental was assessed by New Ballard scale and leg recoil and Ankle dorsiflexion items from Dubowitz scale. Data were analyzed using SPSS version 13. Results: TIMP and neuromuscular scores improved in all groups. Motor performance did not differ between groups at 34 weeks PMA. Postural tone of leg recoil was significantly higher in physical activity groups post intervention. Conclusion: Physical activities and containment didn’t have different effects on motor performance in infants born preterm. Leg recoil of neuromuscular development items was affected by physical activity programs. PMID:28299299

  11. Neuromuscular Fatigue During 200 M Breaststroke

    Directory of Open Access Journals (Sweden)

    Ana Conceição

    2014-03-01

    Full Text Available The aims of this study were: i to analyze activation patterns of four upper limb muscles (duration of the active and non-active phase in each lap of 200m breaststroke, ii quantify neuromuscular fatigue, with kinematics and physiologic assessment. Surface electromyogram was collected for the biceps brachii, deltoid anterior, pectoralis major and triceps brachii of nine male swimmers performing a maximal 200m breaststroke trial. Swimming speed, SL, SR, SI decreased from the 1st to the 3rd lap. SR increased on the 4th lap (35.91 ± 2.99 stroke·min-1. Peak blood lactate was 13.02 ± 1.72 mmol·l-1 three minutes after the maximal trial. The EMG average rectified value (ARV increased at the end of the race for all selected muscles, but the deltoid anterior and pectoralis major in the 1st lap and for biceps brachii, deltoid anterior and triceps brachii in the 4th lap. The mean frequency of the power spectral density (MNF decreased at the 4th lap for all muscles. These findings suggest the occurrence of fatigue at the beginning of the 2nd lap in the 200m breaststroke trial, characterized by changes in kinematic parameters and selective changes in upper limb muscle action. There was a trend towards a non-linear fatigue state.

  12. Neuromuscular dentistry: Occlusal diseases and posture.

    Science.gov (United States)

    Khan, Mohd Toseef; Verma, Sanjeev Kumar; Maheshwari, Sandhya; Zahid, Syed Naved; Chaudhary, Prabhat K

    2013-01-01

    Neuromuscular dentistry has been a controversial topic in the field of dentistry and still remains debatable. The issue of good occlusion and sound health has been repeatedly discussed. Sometimes we get complains of sensitive teeth and sometimes of tired facial muscles on getting up in the morning. Owing to the intimate relation of masticatory apparatus with the cranium and cervico-scapular muscular system, the disorders in any system, draw attention from concerned clinicians involved in management, to develop an integrated treatment protocol for the suffering patients. There may be patients reporting to the dental clinics after an occlusal restoration or extraction, having pain in or around the temporomandibular joint, headache or neck pain. Although their esthetic demands must not be undermined during the course of treatment plan, whenever dental treatment of any sort is planned, occlusion/bite should be given prime importance. Very few dentist are able to diagnose the occlusal disease and of those who diagnose many people resort to aggressive treatment modalities. This paper aims to report the signs of occlusal disease, and discuss their association with TMDs and posture.

  13. Assessment of Motor Units in Neuromuscular Disease.

    Science.gov (United States)

    Henderson, Robert D; McCombe, Pamela A

    2017-01-01

    The motor unit comprises the anterior horn cell, its axon, and the muscle fibers that it innervates. Although the true number of motor units is unknown, the number of motor units appears to vary greatly between different muscles and between different individuals. Assessment of the number and function of motor units is needed in diseases of the anterior horn cell and other motor nerve disorders. Amyotrophic lateral sclerosis is the most important disease of anterior horn cells. The need for an effective biomarker for assessing disease progression and for use in clinical trials in amyotrophic lateral sclerosis has stimulated the study of methods to measure the number of motor units. Since 1970 a number of different methods, including the incremental, F-wave, multipoint, and statistical methods, have been developed but none has achieved widespread applicability. Two methods (MUNIX and the multipoint incremental method) are in current use across multiple centres and are discussed in detail in this review, together with other recently published methods. Imaging with magnetic resonance and ultrasound is increasingly being applied to this area. Motor unit number estimates have also been applied to other neuromuscular diseases such as spinal muscular atrophy, compression neuropathies, and prior poliomyelitis. The need for an objective measure for the assessment of motor units remains tantalizingly close but unfulfilled in 2016.

  14. Neuromuscular disorders in chronic alcohol intoxication

    Directory of Open Access Journals (Sweden)

    A. Yu. Emelyanova

    2015-01-01

    Full Text Available The paper reviews the present-day Russian and foreign literature on neuromuscular disorders in chronic alcohol intoxication. The most common manifestations of alcohol disease include alcoholic polyneuropathy (PNP and alcohol-induced skeletal muscle injury. The clinical polymorphism of alcoholic PNP is discussed. The paper considers a chronic sensory automatic form due to the direct toxic effects of ethanol and its metabolites during long-term alcohol intoxication, as well as acute/subacute sensorimotor neuropathy, the basis for the pathogenesis of which is B group vitamins, predominantly thiamine, deficiency that develops in the presence of drinking bouts concurrent with malnutrition and/or alcohol-related gastrointestinal tract diseases. In addition to nonuse of alcohol and a properly balanced diet, antioxidant therapy with alphalipoic acid and neurotropic B group vitamins is considered to be pathogenetic therapy for neuropathy. The most common and least studied clinicalform of alcohol-induced musculoskeletal injury is chronic alcoholic myopathy (AM, the diagnostic standard for which is morphometricand immunohistochemical examination of a muscle biopsy specimen. The morphological base for this form of myopathy is predominantly type 2 muscle fiber atrophy caused by impaired protein synthesis and a decreased regenerative potential of muscle fiber. The efficacy of antioxidants and leucine-containing amino acid mixtures in the treatment of chronic AM is discussed.

  15. Mechanism of controlled release kinetics from medical devices

    Directory of Open Access Journals (Sweden)

    A. Raval

    2010-06-01

    Full Text Available Utilization of biodegradable polymers for controlled drug delivery has gained immense attention in the pharmaceutical and medical device industry to administer various drugs, proteins and other bio-molecules both systematically and locally to cure several diseases. The efficacy and toxicity of this local therapeutics depends upon drug release kinetics, which will further decide drug deposition, distribution, and retention at the target site. Drug Eluting Stent (DES presently possesses clinical importance as an alternative to Coronary Artery Bypass Grafting due to the ease of the procedure and comparable safety and efficacy. Many models have been developed to describe the drug delivery from polymeric carriers based on the different mechanisms which control the release phenomenon from DES. Advanced characterization techniques facilitate an understanding of the complexities behind design and related drug release behavior of drug eluting stents, which aids in the development of improved future drug eluting systems. This review discusses different drug release mechanisms, engineering principles, mathematical models and current trends that are proposed for drug-polymer coated medical devices such as cardiovascular stents and different analytical methods currently utilized to probe diverse characteristics of drug eluting devices.

  16. Neural mechanisms of attentional control in mindfulness meditation

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    Peter eMalinowski

    2013-02-01

    Full Text Available The scientific interest in meditation and mindfulness practice has recently seen an unprecedented surge. After an initial phase of presenting beneficial effects of mindfulness practice in various domains, research is now seeking to unravel the underlying psychological and neurophysiological mechanisms. Advances in understanding these processes are required for improving and fine-tuning mindfulness-based interventions that target specific conditions such as eating disorders or attention deficit hyperactivity disorders. This review presents a theoretical framework that emphasizes the central role of attentional control mechanisms in the development of mindfulness skills. It discusses the phenomenological level of experience during meditation, the different attentional functions that are involved, and relates these to the brain networks that subserve these functions. On the basis of currently available empirical evidence specific processes as to how attention exerts its positive influence are considered and it is concluded that meditation practice appears to positively impact attentional functions by improving resource allocation processes. As a result, attentional resources are allocated more fully during early processing phases which subsequently enhance further processing. Neural changes resulting from a pure form of mindfulness practice that is central to most mindfulness programs are considered from the perspective that they constitute a useful reference point for future research. Furthermore, possible interrelations between the improvement of attentional control and emotion regulation skills are discussed.

  17. Central chemoreceptors and neural mechanisms of cardiorespiratory control

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    T.S. Moreira

    2011-09-01

    Full Text Available The arterial partial pressure (P CO2 of carbon dioxide is virtually constant because of the close match between the metabolic production of this gas and its excretion via breathing. Blood gas homeostasis does not rely solely on changes in lung ventilation, but also to a considerable extent on circulatory adjustments that regulate the transport of CO2 from its sites of production to the lungs. The neural mechanisms that coordinate circulatory and ventilatory changes to achieve blood gas homeostasis are the subject of this review. Emphasis will be placed on the control of sympathetic outflow by central chemoreceptors. High levels of CO2 exert an excitatory effect on sympathetic outflow that is mediated by specialized chemoreceptors such as the neurons located in the retrotrapezoid region. In addition, high CO2 causes an aversive awareness in conscious animals, activating wake-promoting pathways such as the noradrenergic neurons. These neuronal groups, which may also be directly activated by brain acidification, have projections that contribute to the CO2-induced rise in breathing and sympathetic outflow. However, since the level of activity of the retrotrapezoid nucleus is regulated by converging inputs from wake-promoting systems, behavior-specific inputs from higher centers and by chemical drive, the main focus of the present manuscript is to review the contribution of central chemoreceptors to the control of autonomic and respiratory mechanisms.

  18. Molecular mechanisms controlling the migration of striatal interneurons.

    Science.gov (United States)

    Villar-Cerviño, Verona; Kappeler, Caroline; Nóbrega-Pereira, Sandrina; Henkemeyer, Mark; Rago, Luciano; Nieto, M Angela; Marín, Oscar

    2015-06-10

    In the developing telencephalon, the medial ganglionic eminence (MGE) generates many cortical and virtually all striatal interneurons. While the molecular mechanisms controlling the migration of interneurons to the cortex have been extensively studied, very little is known about the nature of the signals that guide interneurons to the striatum. Here we report that the allocation of MGE-derived interneurons in the developing striatum of the mouse relies on a combination of chemoattractive and chemorepulsive activities. Specifically, interneurons migrate toward the striatum in response to Nrg1/ErbB4 chemoattraction, and avoid migrating into the adjacent cortical territories by a repulsive activity mediated by EphB/ephrinB signaling. Our results also suggest that the responsiveness of MGE-derived striatal interneurons to these cues is at least in part controlled by the postmitotic activity of the transcription factor Nkx2-1. This study therefore reveals parallel mechanisms for the migration of MGE-derived interneurons to the striatum and the cerebral cortex.

  19. Emergent patterns of growth controlled by multicellular form and mechanics

    Science.gov (United States)

    Nelson, Celeste M.; Jean, Ronald P.; Tan, John L.; Liu, Wendy F.; Sniadecki, Nathan J.; Spector, Alexander A.; Chen, Christopher S.

    2005-01-01

    Spatial patterns of cellular growth generate mechanical stresses that help to push, fold, expand, and deform tissues into their specific forms. Genetic factors are thought to specify patterns of growth and other behaviors to drive morphogenesis. Here, we show that tissue form itself can feed back to regulate patterns of proliferation. Using microfabrication to control the organization of sheets of cells, we demonstrated the emergence of stable patterns of proliferative foci. Regions of concentrated growth corresponded to regions of high tractional stress generated within the sheet, as predicted by a finite-element model of multicellular mechanics and measured directly by using a micromechanical force sensor array. Inhibiting actomyosin-based tension or cadherin-mediated connections between cells disrupted the spatial pattern of proliferation. These findings demonstrate the existence of patterns of mechanical forces that originate from the contraction of cells, emerge from their multicellular organization, and result in patterns of growth. Thus, tissue form is not only a consequence but also an active regulator of tissue growth. PMID:16049098

  20. Some aspects of the neuromuscular system of Ascaris.

    Science.gov (United States)

    del Castillo, J; Rivera, A; Solórzano, S; Serrato, J

    1989-12-01

    1. The structure and physiological properties of the somatic neuromuscular system of the nematode Ascaris lumbricoides var. suum are discussed taking into account early work from this laboratory, the results of other workers, and experiments in progress. 2. Anatomically, the central feature of the somatic musculature is the presence of a specialized muscular, but not contractile, structure: the syncytium or sarcopile, formed by the terminal processes of the muscle cell arms that contact the nerve cord. In this region, they are electrically coupled to one another and form chemical synapses with the nerve fibres. 3. The syncytium serves, primarily, as a nerve-muscle manifold, or device which allows the neural control of the muscle fields with great economy in the amount of nervous tissue, numbers of chemical junctions and quantities of synaptic transmitters. 4. The structure of the syncytium is being studied with the scanning electron microscope. The results reveal the convergence of the arms on discrete sites as they approach the cords, as well as a longitudinal arrangement of the terminal processes as they course over the cords, at least in the posterior region of the animal. 5. The characteristics of the electrical coupling between the muscle cells are being investigated. A pattern has been observed that is dependent on the position of the cell pairs with respect to the longitudinal axis of the animal. 6. A study of signal propagation in the arms has revealed that the morphology of the muscle cells contributes to the extent and preferential direction of propagation.

  1. Fixed and flexible formularies as cost-control mechanisms.

    Science.gov (United States)

    Dewa, Carolyn S; Hoch, Jeffrey S

    2003-06-01

    The purpose of this review is to consider the prevalent types of fixed and flexible formularies, the general economic principles on which they are based and the evidence for their effectiveness in controlling rising drug expenditures. The principal-agent relationship and economic model underlying the various types of formularies are described. The principal-agent model describes a relationship where there is an asymmetry of information between two parties involved in a particular task. As a result of this asymmetry of information, the party with less information (the principal) allows the party with more information (the agent) to make decisions about that task or activity for them. In the case of formularies and cost-control, the principal is the payer. Depending on the incentives offered by the formulary, the agent can alternately be the prescriber, dispenser or patient. The success of a formulary type to control costs is dependent on two main factors. First, the payer (the principal) must identify the agent for whom it is reasonable to create incentives that incorporate the financial risks associated with use of the drugs. Second, the payer must develop a structure that best aligns the principal and agent objectives. The principal-agent framework serves as the vehicle through which the authors examine five major types of formularies (i.e., closed, best available price, reference-based pricing, tiered and open formularies) and their inherent incentives and limitations. The evidence for their effectiveness as cost-control mechanisms is reviewed and the system factors that can affect formulary success will be discussed. Finally, the authors' observations are summarized and interpreted, and suggested implications for future use of formularies in controlling the costs of pharmaceutical use are offered.

  2. The involvement of P2Y12 receptors, NADPH oxidase, and lipid rafts in the action of extracellular ATP on synaptic transmission at the frog neuromuscular junction.

    Science.gov (United States)

    Giniatullin, A; Petrov, A; Giniatullin, R

    2015-01-29

    Adenosine 5'-triphosphate (ATP) is the main co-transmitter accompanying the release of acetylcholine from motor nerve terminals. Previously, we revealed the direct inhibitory action of extracellular ATP on transmitter release via redox-dependent mechanism. However, the receptor mechanism of ATP action and ATP-induced sources of reactive oxygen sources (ROS) remained not fully understood. In the current study, using microelectrode recordings of synaptic currents from the frog neuromuscular junction, we analyzed the receptor subtype involved in synaptic action of ATP, receptor coupling to NADPH oxidase and potential location of ATP receptors within the lipid rafts. Using subtype-specific antagonists, we found that the P2Y13 blocker 2-[(2-chloro-5-nitrophenyl)azo]-5-hydroxy-6-methyl-3-[(phosphonooxy)methyl]-4-pyridinecarboxaldehyde did not prevent the depressant action of ATP. In contrast, the P2Y12 antagonist 2-methylthioadenosine 5'-monophosphate abolished the inhibitory action of ATP, suggesting the key role of P2Y12 receptors in ATP action. As the action of ATP is redox-dependent, we also tested potential involvement of the NADPH oxidase, known as a common inducer of ROS. The depressant action of extracellular ATP was significantly reduced by diphenyleneiodonium chloride and 4-(2-aminoethyl)-benzenesulfonyl fluoride hydrochloride, two structurally different inhibitors of NADPH oxidase, indicating that this enzyme indeed mediates the action of ATP. Since the location and activity of various receptors are often associated with lipid rafts, we next tested whether ATP-driven inhibition depends on lipid rafts. We found that the disruption of lipid rafts with methyl-beta-cyclodextrin reduced and largely delayed the action of ATP. Taken together, these data revealed key steps in the purinergic control of synaptic transmission via P2Y12 receptors associated with lipid rafts, and identified NADPH oxidase as the main source of ATP-induced inhibitory ROS at the neuromuscular

  3. Tratamiento farmacológico de las alteraciones neuromusculares en el paciente crítico Pharmacological treatment neuromuscular impairments in critically ill patients

    Directory of Open Access Journals (Sweden)

    C. Ortiz Leyba

    2006-05-01

    Full Text Available El empleo de fármacos para tratamiento de las alteraciones neuromusculares que se presentan en el enfermo ingresado en una Unidad de Cuidados Intensivos es prácticamente inexistente. El empleo de inmunoglobulinas por vía venosa para el tratamiento de la polineuropatía del paciente crítico (PPC no aporta ninguna evidencia para su uso. Más importancia tiene el tratamiento profiláctico, como es el caso de la administración de una perfusión de insulina para prevenir la hiperglucemias que seasocian a un mayor desarrollo de la PPC. Nuevos datos inducen a pensar que el mecanismo protector de esta perfusión, normalizando los niveles de glucosa se hacen modulando una disfunción endotelial y a unos menores niveles de dimetilarginina asimétrica (ADMA. Con respecto a la miopatía del paciente crítico o a los cuadros de bloqueo neuromuscular prolongado, el tratamiento consiste en evitar el empleo de diversos fármacos que se sabe se asocian al desarrollo de estas entidades como son los corticoides, los relajantes musculares y los aminoglucósidos. Por lo que respecta a la parálisis aguda flácida -infección por el virus del oeste del nilo se han comunicado casos anecdóticos de mejoría con el empleo de corticoides o de interferón, pero su tratamiento rutinario queda aún por establecer.The use of drugs for treating neuromuscular impairments that present in the patient admitted to the Intensive Care Unit is virtually inexistent. The use of intravenous immunoglobulins for managing polyneuropathy of the critically ill patient (PCIP is supported by no evidence. More important is prophylactic therapy, as is the administration of insulin perfusion to prevent hyperglycemia that is associated to increased development of PCIP. New data suggest that the protective mechanism of this perfusion, which normalizes glucose levels, is achieved through the modulation of endothelial dysfunction and lowering levels of asymmetrical di-methyl arginine (ADMA. As

  4. Chemo-mechanical control of neural stem cell differentiation

    Science.gov (United States)

    Geishecker, Emily R.

    Cellular processes such as adhesion, proliferation, and differentiation are controlled in part by cell interactions with the microenvironment. Cells can sense and respond to a variety of stimuli, including soluble and insoluble factors (such as proteins and small molecules) and externally applied mechanical stresses. Mechanical properties of the environment, such as substrate stiffness, have also been suggested to play an important role in cell processes. The roles of both biochemical and mechanical signaling in fate modification of stem cells have been explored independently. However, very few studies have been performed to study well-controlled chemo-mechanotransduction. The objective of this work is to design, synthesize, and characterize a chemo-mechanical substrate to encourage neuronal differentiation of C17.2 neural stem cells. In Chapter 2, Polyacrylamide (PA) gels of varying stiffnesses are functionalized with differing amounts of whole collagen to investigate the role of protein concentration in combination with substrate stiffness. As expected, neurons on the softest substrate were more in number and neuronal morphology than those on stiffer substrates. Neurons appeared locally aligned with an expansive network of neurites. Additional experiments would allow for statistical analysis to determine if and how collagen density impacts C17.2 differentiation in combination with substrate stiffness. Due to difficulties associated with whole protein approaches, a similar platform was developed using mixed adhesive peptides, derived from fibronectin and laminin, and is presented in Chapter 3. The matrix elasticity and peptide concentration can be individually modulated to systematically probe the effects of chemo-mechanical signaling on differentiation of C17.2 cells. Polyacrylamide gel stiffness was confirmed using rheological techniques and found to support values published by Yeung et al. [1]. Cellular growth and differentiation were assessed by cell counts

  5. Neuromuscular monitoring and postoperative residual curarisation: a meta-analysis.

    Science.gov (United States)

    Naguib, M; Kopman, A F; Ensor, J E

    2007-03-01

    We conducted a meta-analysis to examine the effect of intraoperative monitoring of neuromuscular function on the incidence of postoperative residual curarisation (PORC). PORC has been considered present when a patient has a train-of-four (TOF) ratio of < 0.7 or < 0.9. We analysed data from 24 trials (3375 patients) that were published between 1979 and 2005. We excluded data on mivacurium from this meta-analysis because only three studies had examined the incidence of PORC associated with its use. Long- and intermediate-acting neuromuscular blocking drugs had been given to 662 and 2713 patients, respectively. Neuromuscular function was monitored in 823 patients (24.4%). A simple peripheral nerve stimulator was used in 543 patients, and an objective monitor was used in 280. The incidence of PORC was found to be significantly lower after the use of intermediate neuromuscular blocking drugs. We could not demonstrate that the use of an intraoperative neuromuscular function monitor decreased the incidence of PORC.

  6. Current Status of Neuromuscular Reversal and Monitoring: Challenges and Opportunities.

    Science.gov (United States)

    Brull, Sorin J; Kopman, Aaron F

    2017-01-01

    Postoperative residual neuromuscular block has been recognized as a potential problem for decades, and it remains so today. Traditional pharmacologic antagonists (anticholinesterases) are ineffective in reversing profound and deep levels of neuromuscular block; at the opposite end of the recovery curve close to full recovery, anticholinesterases may induce paradoxical muscle weakness. The new selective relaxant-binding agent sugammadex can reverse any depth of block from aminosteroid (but not benzylisoquinolinium) relaxants; however, the effective dose to be administered should be chosen based on objective monitoring of the depth of neuromuscular block.To guide appropriate perioperative management, neuromuscular function assessment with a peripheral nerve stimulator is mandatory. Although in many settings, subjective (visual and tactile) evaluation of muscle responses is used, such evaluation has had limited success in preventing the occurrence of residual paralysis. Clinical evaluations of return of muscle strength (head lift and grip strength) or respiratory parameters (tidal volume and vital capacity) are equally insensitive at detecting neuromuscular weakness. Objective measurement (a train-of-four ratio greater than 0.90) is the only method to determine appropriate timing of tracheal extubation and ensure normal muscle function and patient safety.

  7. Individuals with medial knee osteoarthritis show neuromuscular adaptation when perturbed during walking despite functional and structural impairments

    OpenAIRE

    Kumar, Deepak; Swanik, Charles (Buz); Reisman, Darcy S.; Rudolph, Katherine S.

    2013-01-01

    Neuromuscular control relies on sensory feedback that influences responses to changing external demands, and the normal response is for movement and muscle activation patterns to adapt to repeated perturbations. People with knee osteoarthritis (OA) are known to have pain, quadriceps weakness, and neuromotor deficits that could affect adaption to external perturbations. The aim of this study was to analyze neuromotor adaptation during walking in people with knee OA (n = 38) and controls (n = 2...

  8. The mathematical basis of population rhythms in nervous and neuromuscular systems.

    Science.gov (United States)

    Christakos, C N

    1986-03-01

    The mechanism underlying rhythmical aggregate activity of a population of neural or neuromuscular elements is examined in this report. By making use of the spectral properties of stochastic processes (Papoulis, 1965), it is shown that such population rhythms are the inevitable effect of the rhythmical activities of the individual elements, irrespective of the phase relations of the latter. This result applies to both "discrete" signals, such as spike trains, and "continuous" ones, such as membrane potential fluctuations. It has implications regarding the generation of common physiological rhythms and the preservation of rhythms when converging activity of one of the above two types is transformed into activity of the other type.

  9. Preventing Ischial Pressure Ulcers: III. Clinical Pilot Study of Chronic Neuromuscular Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Hilton M. Kaplan

    2011-01-01

    Full Text Available Objective: BIONs™ (BIOnic Neurons are injectable, wireless microstimulators that make chronic BION Active Seating (BAS possible for pressure ulcer prevention (PUP. Neuromuscular electrical stimulation (NMES produces skeletal motion and activates trophic factors, counteracting three major etiological mechanisms leading to pressure ulcers (PUs: immobility, soft-tissue atrophy, and ischemia. Companion papers I and II reviewed prior experience with NMES for PUP, and analyzed the biomechanical considerations, respectively. This paper presents a treatment strategy derived from this analysis, and the clinical results of the first three cases.

  10. Neuromuscular function and fatigue resistance of the plantar flexors following short-term cycling endurance training

    Directory of Open Access Journals (Sweden)

    Martin eBehrens

    2015-05-01

    Full Text Available Previously published studies on the effect of short-term endurance training on the neuromuscular function of the plantar flexors have shown that the H-reflex elicited at rest and during weak voluntary contractions was increased following the training regime. However, these studies did not test H-reflex modulation during isometric maximum voluntary contraction (iMVC and did not incorporate a control group in their study design to compare the results of the endurance training group to individuals without the endurance training stimulus. Therefore, this randomized controlled study was directed to investigate the neuromuscular function of the plantar flexors at rest and during iMVC before and after eight weeks of cycling endurance training. Twenty-two young adults were randomly assigned to an intervention group and a control group. During neuromuscular testing, rate of torque development, isometric maximum voluntary torque and muscle activation were measured. Triceps surae muscle activation and tibialis anterior muscle co-activation were assessed by normalized root mean square of the EMG signal during the initial phase of contraction (0-100, 100-200 ms and isometric maximum voluntary contraction of the plantar flexors. Furthermore, evoked spinal reflex responses of the soleus muscle (H-reflex evoked at rest and during iMVC, V-wave, peak twitch torques induced by electrical stimulation of the posterior tibial nerve at rest and fatigue resistance were evaluated. The results indicate that the endurance training did not lead to a significant change in any variable of interest. Data of the present study conflict with the outcome of previously published studies that have found an increase in H-reflex excitability after endurance training. However, these studies had not included a control group in their study design as was the case here. It is concluded that short-term cycling endurance training does not necessarily enhance H-reflex responses and fatigue

  11. Neuromuscular function and fatigue resistance of the plantar flexors following short-term cycling endurance training.

    Science.gov (United States)

    Behrens, Martin; Weippert, Matthias; Wassermann, Franziska; Bader, Rainer; Bruhn, Sven; Mau-Moeller, Anett

    2015-01-01

    Previously published studies on the effect of short-term endurance training on neuromuscular function of the plantar flexors have shown that the H-reflex elicited at rest and during weak voluntary contractions was increased following the training regime. However, these studies did not test H-reflex modulation during isometric maximum voluntary contraction (iMVC) and did not incorporate a control group in their study design to compare the results of the endurance training group to individuals without the endurance training stimulus. Therefore, this randomized controlled study was directed to investigate the neuromuscular function of the plantar flexors at rest and during iMVC before and after 8 weeks of cycling endurance training. Twenty-two young adults were randomly assigned to an intervention group and a control group. During neuromuscular testing, rate of torque development, isometric maximum voluntary torque and muscle activation were measured. Triceps surae muscle activation and tibialis anterior muscle co-activation were assessed by normalized root mean square of the EMG signal during the initial phase of contraction (0-100, 100-200 ms) and iMVC of the plantar flexors. Furthermore, evoked spinal reflex responses of the soleus muscle (H-reflex evoked at rest and during iMVC, V-wave), peak twitch torques induced by electrical stimulation of the posterior tibial nerve at rest and fatigue resistance were evaluated. The results indicate that cycling endurance training did not lead to a significant change in any variable of interest. Data of the present study conflict with the outcome of previously published studies that have found an increase in H-reflex excitability after endurance training. However, these studies had not included a control group in their study design as was the case here. It is concluded that short-term cycling endurance training does not necessarily enhance H-reflex responses and fatigue resistance.

  12. Effects of hindlimb unloading on neuromuscular development of neonatal rats

    Science.gov (United States)

    Huckstorf, B. L.; Slocum, G. R.; Bain, J. L.; Reiser, P. M.; Sedlak, F. R.; Wong-Riley, M. T.; Riley, D. A.

    2000-01-01

    We hypothesized that hindlimb suspension unloading of 8-day-old neonatal rats would disrupt the normal development of muscle fiber types and the motor innervation of the antigravity (weightbearing) soleus muscles but not extensor digitorum longus (EDL) muscles. Five rats were suspended 4.5 h and returned 1.5 h to the dam for nursing on a 24 h cycle for 9 days. To control for isolation from the dam, the remaining five littermates were removed on the same schedule but not suspended. Another litter of 10 rats housed in the same room provided a vivarium control. Fibers were typed by myofibrillar ATPase histochemistry and immunostaining for embryonic, slow, fast IIA and fast IIB isomyosins. The percentage of multiple innervation and the complexity of singly-innervated motor terminal endings were assessed in silver/cholinesterase stained sections. Unique to the soleus, unloading accelerated production of fast IIA myosin, delayed expression of slow myosin and retarded increases in standardized muscle weight and fiber size. Loss of multiple innervation was not delayed. However, fewer than normal motor nerve endings achieved complexity. Suspended rats continued unloaded hindlimb movements. These findings suggest that motor neurons resolve multiple innervation through nerve impulse activity, whereas the postsynaptic element (muscle fiber) controls endplate size, which regulates motor terminal arborization. Unexpectedly, in the EDL of unloaded rats, transition from embryonic to fast myosin expression was retarded. Suspension-related foot drop, which stretches and chronically loads EDL, may have prevented fast fiber differentiation. These results demonstrate that neuromuscular development of both weightbearing and non-weightbearing muscles in rats is dependent upon and modulated by hindlimb loading.

  13. The inner-city Skater Facility - playground or control mechanism?

    DEFF Research Database (Denmark)

    Gravesen, David Thore

    2015-01-01

    The inner-city Skater Facility - playground or control mechanism? In 2013, the municipality in Horsens, a medium-sized provincial town in Denmark, bestowed the city's children and young people a skater facility at the city's central squares. Officially, the municipality donated the facility to give...... local children and young people an opportunity to use their leisure time stimulating their bodies, having a great time with friends and other urban dwellers. The gift is accompanied by a number of (more or less camouflaged) crime prevention- and social education agendas, carried out by the SSP (a...... special Social services, School and Police unit), that observe, mingle and socialize at the facility. The social workers affiliated with the SSP understand and define their role in contradiction to the official agenda. The social workers seek to pull the young people off the street and get them to enroll...

  14. Mechanism of anterior-posterior polarity control in planarians

    Energy Technology Data Exchange (ETDEWEB)

    Lange, C.S.; Steele, V.E.

    1978-01-01

    The substance which inhibits brain formation in the regenerating planarian Dugesia etrusca was found to be a large molecule, at least in part protein, which electrophoreses as an electronegative moiety in pH 6.8 buffer. A model is presented, based on this finding and previous studies, which proposes an electrochemical mechanism for the control of polarity and possibly for the maintenance of tissue organization in planarians. It is proposed that a bioelectric field exists and moves the electronegative brain-inhibiting substance in a posterior direction, establishing polarity. This model explains the polarity reversal experiments using external fields and many of the previously unexplained classical planarian experiments. Data are presented demonstrating the existence, magnitude, and polarity of this bioelectric field, which is not greatly altered upon decapitation, all in accord with predictions of the model.

  15. Cellular and Humoral Mechanisms Involved in the Control of Tuberculosis

    Directory of Open Access Journals (Sweden)

    Joaquin Zuñiga

    2012-01-01

    Full Text Available Mycobacterium tuberculosis (Mtb infection is a major international public health problem. One-third of the world's population is thought to have latent tuberculosis, a condition where individuals are infected by the intracellular bacteria without active disease but are at risk for reactivation, if their immune system fails. Here, we discuss the role of nonspecific inflammatory responses mediated by cytokines and chemokines induced by interaction of innate receptors expressed in macrophages and dendritic cells (DCs. We also review current information regarding the importance of several cytokines including IL-17/IL-23 in the development of protective cellular and antibody-mediated protective responses against Mtb and their influence in containment of the infection. Finally, in this paper, emphasis is placed on the mechanisms of failure of Mtb control, including the immune dysregulation induced by the treatment with biological drugs in different autoimmune diseases. Further functional studies, focused on the mechanisms involved in the early host-Mtb interactions and the interplay between host innate and acquired immunity against Mtb, may be helpful to improve the understanding of protective responses in the lung and in the development of novel therapeutic and prophylactic tools in TB.

  16. Lattice Metamaterials with Mechanically Tunable Poisson's Ratio for Vibration Control

    Science.gov (United States)

    Chen, Yanyu; Li, Tiantian; Scarpa, Fabrizio; Wang, Lifeng

    2017-02-01

    Metamaterials with artificially designed architectures are increasingly considered as new paradigmatic material systems with unusual physical properties. Here, we report a class of architected lattice metamaterials with mechanically tunable negative Poisson's ratios and vibration-mitigation capability. The proposed lattice metamaterials are built by replacing regular straight beams with sinusoidally shaped ones, which are highly stretchable under uniaxial tension. Our experimental and numerical results indicate that the proposed lattices exhibit extreme Poisson's-ratio variations between -0.7 and 0.5 over large tensile deformations up to 50%. This large variation of Poisson's-ratio values is attributed to the deformation pattern switching from bending to stretching within the sinusoidally shaped beams. The interplay between the multiscale (ligament and cell) architecture and wave propagation also enables remarkable broadband vibration-mitigation capability of the lattice metamaterials, which can be dynamically tuned by an external mechanical stimulus. The material design strategy provides insights into the development of classes of architected metamaterials with potential applications including energy absorption, tunable acoustics, vibration control, responsive devices, soft robotics, and stretchable electronics.

  17. An Effective Feedback Control Mechanism for DiffServ Architecture

    Institute of Scientific and Technical Information of China (English)

    王重钢; 隆克平; 杨健; 程时端

    2002-01-01

    As a scalable QoS (Quality of Service) architecture, DiffServ (Differentiated Service) mainly consists of two components: traffic conditioning at the edge of the DiffServ domain and simple packet forwarding inside the DiffServ domain. DiffServ has many advantages such as flexibility, scalability and simplicity. But when providing AF (Assured Forwarding)services, DiffServ has some problems such as unfairness among aggregated flows or among microflows belonging to an aggregated flow. In this paper, a feedback mechanism for AF aggregated flows is proposed to solve this problem. Simulation results show that this mechanism does improve the performance of DiffServ. First, it can improve the fairness among aggregated flows and make DiffServ more friendly toward TCP (Transmission Control Protocol) flows. Second,it can decrease the buffer requirements at the congested router and thus obtain lower delay and packet loss rate. Third, it also keeps almost the same link utility as in normal DiffServ.Finally, it is simple and easy to be implemented.

  18. Mechanisms controlling the distribution of two invasive Bromus species

    Directory of Open Access Journals (Sweden)

    Olga Bykova

    2014-03-01

    Full Text Available In order to predict future range shifts for invasive species it is important to explore their ability to acclimate to the new environment and understand physiological and reproductive constraints controlling their distribution. My dissertation studied mechanisms by which temperature may affect the distribution of two aggressive plant invaders in North America, Bromus tectorum and Bromus rubens. I first evaluated winter freezing tolerance of Bromus species and demonstrated that the mechanism explaining their distinct northern range limits is different acquisition time of freezing tolerance. While B. rubens has a slower rate of freezing acclimation that leads to intolerance of sudden, late-autumn drops in temperature below -12°C, B. tectorum rapidly hardens and so is not impacted by the sudden onset of severe late-autumn cold. In addition, the analysis of male reproductive development and seed production showed that neither species produces seed at or above 36°C, due to complete pollen sterility, which might trigger climate-mediated range contractions at B. tectorum and B. rubens southern margins. Finally, a detailed gas-exchange analysis combined with biochemical modelling demonstrated that both species acclimate to a broad range of temperatures and photosynthetic response to temperature does not explain their current range separation.

  19. Passive Flow Separation Control Mechanism Inspired by Shark Skin

    Science.gov (United States)

    Oakley, India; Lang, Amy

    2015-11-01

    The following experimental work seeks to examine shark scales as passive flow-actuated separation control mechanisms. It is hypothesized that the actuation of these scales can in fact reduce pressure drag by inhibiting flow reversal and thereby prevent flow separation. In order to examine this mechanism at a fundamental level, three-dimensional sharkskin scales were simplified and modeled as two-dimensional flaps. To further simplify the experiment, the flaps were observed within a laminar boundary layer. The laminar boundary layer was grown over a long flat plate that was placed inside a water tunnel. A rotating cylinder was also used to induce an unsteady, increasing adverse pressure gradient, which generated a reversing flow. In order to visualize the potential actuation of the two-dimensional flaps DPIV (digital particle image velocimetry) was utilized. Three main objectives for this work included, the actuation of the two-dimensional flaps, the resistance to a reversed flow as a result of flap actuation and the prevention of flow separation. However once the experiment was conducted the flaps did not perform as previously hypothesized. The adverse pressure gradient induced by the rotating cylinder did not produce a reversing flow powerful enough to actuate the flaps. NSF REU Site Award 1358991.

  20. Individuals with medial knee osteoarthritis show neuromuscular adaptation when perturbed during walking despite functional and structural impairments.

    Science.gov (United States)

    Kumar, Deepak; Swanik, Charles Buz; Reisman, Darcy S; Rudolph, Katherine S

    2014-01-01

    Neuromuscular control relies on sensory feedback that influences responses to changing external demands, and the normal response is for movement and muscle activation patterns to adapt to repeated perturbations. People with knee osteoarthritis (OA) are known to have pain, quadriceps weakness, and neuromotor deficits that could affect adaption to external perturbations. The aim of this study was to analyze neuromotor adaptation during walking in people with knee OA (n = 38) and controls (n = 23). Disability, quadriceps strength, joint space width, malalignment, and proprioception were assessed. Kinematic and EMG data were collected during undisturbed walking and during perturbations that caused lateral translation of the foot at initial contact. Knee excursions and EMG magnitudes were analyzed. Subjects with OA walked with less knee motion and higher muscle activation and had greater pain, limitations in function, quadriceps weakness, and malalignment, but no difference was observed in proprioception. Both groups showed increased EMG and decreased knee motion in response to the first perturbation, followed by progressively decreased EMG activity and increased knee motion during midstance over the first five perturbations, but no group differences were observed. Over 30 trials, EMG levels returned to those of normal walking. The results illustrate that people with knee OA respond similarly to healthy individuals when exposed to challenging perturbations during functional weight-bearing activities despite structural, functional, and neuromotor impairments. Mechanisms underlying the adaptive response in people with knee OA need further study.

  1. Spatial factors and muscle spindle input influence the generation of neuromuscular responses to stimulation of the human foot

    Science.gov (United States)

    Layne, Charles S.; Forth, Katharine E.; Abercromby, Andrew F. J.

    2005-05-01

    Removal of the mechanical pressure gradient on the soles leads to physiological adaptations that ultimately result in neuromotor degradation during spaceflight. We propose that mechanical stimulation of the soles serves to partially restore the afference associated with bipedal loading and assists in attenuating the negative neuromotor consequences of spaceflight. A dynamic foot stimulus device was used to stimulate the soles in a variety of conditions with different stimulation locations, stimulation patterns and muscle spindle input. Surface electromyography revealed the lateral side of the sole elicited the greatest neuromuscular response in ankle musculature, followed by the medial side, then the heel. These responses were modified by preceding stimulation. Neuromuscular responses were also influenced by the level of muscle spindle input. These results provide important information that can be used to guide the development of a "passive" countermeasure that relies on sole stimulation and can supplement existing exercise protocols during spaceflight.

  2. Effects of neuromuscular training (NEMEX-TJR) on patient-reported outcomes and physical function in severe primary hip or knee osteoarthritis

    DEFF Research Database (Denmark)

    Ageberg, Eva; Nilsdotter, Anna; Kosek, Eva;

    2013-01-01

    The benefits of exercise in mild and moderate knee or hip osteoarthritis (OA) are apparent, but the evidence in severe OA is less clear. We recently reported that neuromuscular training was well tolerated and feasible in patients with severe primary hip or knee OA. The aims of this controlled bef...... before-and-after study were to compare baseline status to an age-matched population-based reference group and to examine the effects of neuromuscular training on patient-reported outcomes and physical function in patients with severe primary OA of the hip or knee.......The benefits of exercise in mild and moderate knee or hip osteoarthritis (OA) are apparent, but the evidence in severe OA is less clear. We recently reported that neuromuscular training was well tolerated and feasible in patients with severe primary hip or knee OA. The aims of this controlled...

  3. Exercise Therapy in Spinobulbar Muscular Atrophy and Other Neuromuscular Disorders

    DEFF Research Database (Denmark)

    Dahlqvist, Julia Rebecka; Vissing, John

    2016-01-01

    There is no curative treatment for most neuromuscular disorders. Exercise, as a treatment for these diseases, has therefore received growing attention. When executed properly, exercise can maintain and improve health and reduce the risk of cardiovascular disease, obesity, and diabetes. In persons...... in patients with neuromuscular diseases associated with weakness and wasting. We review studies that have investigated different types of exercise in both myopathies and motor neuron diseases, with particular emphasis on training of persons affected by spinobulbar muscular atrophy (SBMA). Finally, we provide...... with muscle wasting due to neuromuscular conditions, however, a common belief has been that physical activity could accelerate degeneration of the diseased muscle and a careful approach to training has therefore been suggested. In this review, we describe the current knowledge about physical training...

  4. Effects of the aminoglycoside antibiotics, streptomycin and neomycin, on neuromuscular transmission. I. Presynaptic considerations.

    Science.gov (United States)

    Fiekers, J F

    1983-06-01

    The effects of two aminoglycoside antibiotics, streptomycin and neomycin, were studied in voltage-clamped transected twitch fibers of the costocutaneous muscles of garter snakes (species Thamnophis). The concentration-dependent effects of each antibiotic were quantitated by measuring miniature end-plate currents (mepcs) and evoked end-plate currents (epcs) in a single fiber before and in the presence of a wide range of concentrations of each antibiotic. The amplitude and the kinetics of these currents were studied and estimates of the quantal content of evoked transmitter release determined by the direct method of mean ratios, epc/mepc. A distinct separation was obtained between the concentrations of each antibiotic which demonstrated either pre- or postsynaptic actions. Both streptomycin and neomycin produced a concentration-dependent reduction in epc amplitude at concentrations which did not reduce mepc amplitude. Thus, the primary site of action for these antibiotics was considered of presynaptic origin. Streptomycin was approximately one-tenth as active as neomycin in reducing quantal release of acetylcholine. The marked depression in epc amplitude and quantal content produced by high concentrations of each antibiotic were reversed by elevating the external calcium concentration. Double logarithmic plots of the relationship between external calcium concentration and epc amplitude yielded a slope of approximately 3.8 in control physiological solution. In the presence of blocking concentrations of each antibiotic, increasing the external calcium concentration caused a parallel shift to the right of this relationship. These results suggest that the major mechanism for the neuromuscular depression produced by these aminoglycoside antibiotics is a competitive antagonism with calcium for a common presynaptic site required for evoked transmitter release.

  5. Quality control mechanisms of protein biogenesis: proteostasis dies hard

    Directory of Open Access Journals (Sweden)

    Timothy Jan Bergmann

    2016-10-01

    Full Text Available The biosynthesis of proteins entails a complex series of chemical reactions that transform the information stored in the nucleic acid sequence into a polypeptide chain that needs to properly fold and reach its functional location in or outside the cell. It is of no surprise that errors might occur that alter the polypeptide sequence leading to a non-functional proteins or that impede delivery of proteins at the appropriate site of activity. In order to minimize such mistakes and guarantee the synthesis of the correct amount and quality of the proteome, cells have developed folding, quality control, degradation and transport mechanisms that ensure and tightly regulate protein biogenesis. Genetic mutations, harsh environmental conditions or attack by pathogens can subvert the cellular quality control machineries and perturb cellular proteostasis leading to pathological conditions. This review summarizes basic concepts of the flow of information from DNA to folded and active proteins and to the variable fidelity (from incredibly high to quite sloppy characterizing these processes. We will give particular emphasis on events that maintain or recover the homeostasis of the endoplasmic reticulum (ER, a major site of proteins synthesis and folding in eukaryotic cells. Finally, we will report on how cells can adapt to stressful conditions, how perturbation of ER homeostasis may result in diseases and how these can be treated.

  6. Shark Skin Bristling as a Passive Mechanism for Separation Control

    Science.gov (United States)

    Wheelus, Jennifer; Lang, Amy; Jones, Emily

    2011-11-01

    The skin of fast-swimming sharks is proposed to have mechanisms to reduce drag and delay flow separation. The skin of fast-swimming and agile sharks is covered with small teeth-like denticles on the order of 0.2 mm. The shortfin mako is one of the fastest and most agile ocean predators creating the need to minimize its pressure drag by controlling flow separation. Biological studies of the shortfin mako skin have shown the passive bristling angle of their denticles to exceed 50 degrees in areas on the flank corresponding to the locations likely to experience separation first. It is proposed that reversing flow, as occurs at the onset of separation in a turbulent boundary layer, would activate denticle bristling and hinder local separation from leading to global separation over the shark. This study focuses on the denticle reaction to various reversed flow conditions using a pulsating jet. Mako shark skin was subjected to numerous reversed flow velocities to determine the bristling onset velocity. Digital Particle Image Velocimetry (DPIV) and digital video were used to determine the flow conditions and denticle behavior. The effect of reversed flow velocity on denticle bristling and its relation to separation control will be discussed. Research funded by NSF (award 0932352).

  7. Mechanical stratigraphic controls on natural fracture spacing and penetration

    Science.gov (United States)

    McGinnis, Ronald N.; Ferrill, David A.; Morris, Alan P.; Smart, Kevin J.; Lehrmann, Daniel

    2017-02-01

    Fine-grained low permeability sedimentary rocks, such as shale and mudrock, have drawn attention as unconventional hydrocarbon reservoirs. Fracturing - both natural and induced - is extremely important for increasing permeability in otherwise low-permeability rock. We analyze natural extension fracture networks within a complete measured outcrop section of the Ernst Member of the Boquillas Formation in Big Bend National Park, west Texas. Results of bed-center, dip-parallel scanline surveys demonstrate nearly identical fracture strikes and slight variation in dip between mudrock, chalk, and limestone beds. Fracture spacing tends to increase proportional to bed thickness in limestone and chalk beds; however, dramatic differences in fracture spacing are observed in mudrock. A direct relationship is observed between fracture spacing/thickness ratio and rock competence. Vertical fracture penetrations measured from the middle of chalk and limestone beds generally extend to and often beyond bed boundaries into the vertically adjacent mudrock beds. In contrast, fractures in the mudrock beds rarely penetrate beyond the bed boundaries into the adjacent carbonate beds. Consequently, natural bed-perpendicular fracture connectivity through the mechanically layered sequence generally is poor. Fracture connectivity strongly influences permeability architecture, and fracture prediction should consider thin bed-scale control on fracture heights and the strong lithologic control on fracture spacing.

  8. Neuromuscular adaptations following prepubescent strength training.

    Science.gov (United States)

    Ozmun, J C; Mikesky, A E; Surburg, P R

    1994-04-01

    Underlying mechanisms of prepubescent strength gains following resistance training are speculative. The purpose of this investigation was to determine the effects of 8 wk of resistance training on muscular strength, integrated EMG amplitude (IEMG), and arm anthropometrics of prepubescent youth. Sixteen subjects (8 males, 8 females) were randomly assigned to trained or control groups. All subjects (mean age = 10.3 yr) were of prepubertal status according to the criteria of Tanner. The trained group performed three sets (7-11 repetitions) of bicep curls with dumbbells three times per week for 8 wk. Pre- and posttraining measurements included isotonic and isokinetic strength of the elbow flexors, arm anthropometrics, and IEMG of the biceps brachii. Planned comparisons for a 2 x 2 (group by test) ANOVA model were used for data analysis. Significant isotonic (22.6%) and isokinetic (27.8%) strength gains were observed in the trained group without corresponding changes in arm circumference or skinfolds. The IEMG amplitude increased 16.8% (P < 0.05). The control group did not demonstrate any significant changes in the parameters measured. Early gains in muscular strength resulting from resistance training prepubescent children may be attributed to increased muscle activation.

  9. Mechanical and dosimetric quality control for computer controlled radiotherapy treatment equipment.

    Science.gov (United States)

    Thompson, A V; Lam, K L; Balter, J M; McShan, D L; Martel, M K; Weaver, T A; Fraass, B A; Ten Haken, R K

    1995-05-01

    Modern computer controlled radiotherapy treatment equipment offers the possibility of delivering complex, multiple field treatments with minimal operator intervention, thus making multiple field conformal therapy practical. Conventional quality control programs are inadequate for this new technology, so new quality control procedures are needed. A reasonably fast, sensitive, and complete daily quality control program has been developed in our clinic that includes nearly automated mechanical as well as dosimetric tests. Automated delivery of these quality control fields is performed by the control system of the MM50 racetrack microtron, directed by the CCRS sequence processor [D. L. McShan and B. A. Fraass, Proceedings of the XIth International Conference on the use of computers in Radiation Therapy, 20-24 March 1994, Manchester, U.K. (North Western Medical Physics Department, Manchester, U.K., 1994), pp. 210-211], which controls the treatment process. The mechanical tests involve multiple irradiations of a single film to check the accuracy and reproducibility of the computer controlled setup of gantry and collimator angles, table orientation, collimator jaws, and multileaf collimator shape. The dosimetric tests, which involve multiple irradiations of an array of ionization chambers in a commercial dose detector (Keithly model 90100 Tracker System) rigidly attached to the head of the treatment gantry, check the output and symmetry of the treatment unit as a function of gantry and collimator angle and other parameters. For each of the dosimetric tests, readings from the five ionization chambers are automatically read out, stored, and analyzed by the computer, along with the geometric parameters of the treatment unit for that beam.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Cell shape, cytoskeletal mechanics, and cell cycle control in angiogenesis

    Science.gov (United States)

    Ingber, D. E.; Prusty, D.; Sun, Z.; Betensky, H.; Wang, N.

    1995-01-01

    Capillary endothelial cells can be switched between growth and differentiation by altering cell-extracellular matrix interactions and thereby, modulating cell shape. Studies were carried out to determine when cell shape exerts its growth-regulatory influence during cell cycle progression and to explore the role of cytoskeletal structure and mechanics in this control mechanism. When G0-synchronized cells were cultured in basic fibroblast growth factor (FGF)-containing defined medium on dishes coated with increasing densities of fibronectin or a synthetic integrin ligand (RGD-containing peptide), cell spreading, nuclear extension, and DNA synthesis all increased in parallel. To determine the minimum time cells must be adherent and spread on extracellular matrix (ECM) to gain entry into S phase, cells were removed with trypsin or induced to retract using cytochalasin D at different times after plating. Both approaches revealed that cells must remain extended for approximately 12-15 h and hence, most of G1, in order to enter S phase. After this restriction point was passed, normally 'anchorage-dependent' endothelial cells turned on DNA synthesis even when round and in suspension. The importance of actin-containing microfilaments in shape-dependent growth control was confirmed by culturing cells in the presence of cytochalasin D (25-1000 ng ml-1): dose-dependent inhibition of cell spreading, nuclear extension, and DNA synthesis resulted. In contrast, induction of microtubule disassembly using nocodazole had little effect on cell or nuclear spreading and only partially inhibited DNA synthesis. Interestingly, combination of nocodazole with a suboptimal dose of cytochalasin D (100 ng ml-1) resulted in potent inhibition of both spreading and growth, suggesting that microtubules are redundant structural elements which can provide critical load-bearing functions when microfilaments are partially compromised. Similar synergism between nocodazole and cytochalasin D was observed

  11. Train-of-four fade during onset of neuromuscular block with nondepolarising neuromuscular blocking agents.

    Science.gov (United States)

    Gibson, F M; Mirakhur, R K

    1989-04-01

    Fade in the train-of-four (TOF) responses during onset of neuromuscular block was studied following administration of atracurium (225 or 450 micrograms/kg), vecuronium (40 or 80 micrograms/kg), pancuronium (60 or 120 micrograms/kg) and tubocurarine (450 micrograms/kg). TOF ratios were measured at approximate heights of T1 (first response in the TOF) of 75, 50 and 25%. Fade in TOF increased as the height of T1 decreased, with maximum fade being observed at T1 of 25%. The greatest difference between relaxants was observed at T1 of 25%, vecuronium showing the least fade and pancuronium, atracurium and tubocurarine showing increasing fade, in that order. The difference between atracurium and tubocurarine or between vecuronium and pancuronium was not significant, but the degree of TOF fade was significantly greater with atracurium and tubocurarine in comparison to vecuronium or pancuronium.

  12. New techniques in the tissue diagnosis of gastrointestinal neuromuscular diseases

    Institute of Scientific and Technical Information of China (English)

    Charles H Knowles; Joanne E Martin

    2009-01-01

    Gastrointestinal neuromuscular diseases are a clinically heterogeneous group of disorders of children and adults in which symptoms are presumed or proven to arise as a result of neuromuscular (including interstitial cell of Cajal) dysfunction. Common to most of these diseases are symptoms of impaired motor activity which manifest as slowed or obstructed transit with or without evidence of transient or persistent radiological visceral dilatation. A variety of histopathological techniques and allied investigations are being increasingly applied to tissue biopsies from such patients. This review outlines some of the more recent advances in this field, particularly in the most contentious area of small bowel disease manifesting as intestinal pseudo-obstruction.

  13. Neuromuscular exercise as treatment of degenerative knee disease

    DEFF Research Database (Denmark)

    Ageberg, Eva; Roos, Ewa M.

    2015-01-01

    Exercise is recommended as first-line treatment of degenerative knee disease. Our hypothesis is that neuromuscular exercise is feasible and at least as effective as tradionally used strength or aerobic training, but aims to more closely target the sensorimotor deficiencies and functional...... instability associated with the degenerative knee disease than traditionally used training methods.SUMMARY FOR TABLE OF CONTENTS PAGECurrent data suggests that the effect from neuromuscular exercise on pain and function is comparable to the effects seen from other forms of exercise....

  14. Prevention and management of limb contractures in neuromuscular diseases.

    Science.gov (United States)

    Skalsky, Andrew J; McDonald, Craig M

    2012-08-01

    Limb contractures are a common impairment in neuromuscular diseases. They contribute to increased disability from decreased motor performance, mobility limitations, reduced functional range of motion, loss of function for activities of daily living, and increased pain. The pathogenesis of contractures is multifactorial. Myopathic conditions are associated with more severe limb contractures compared with neuropathic disorders. Although the evidence supporting the efficacy of multiple interventions to improve range of motion in neuromuscular diseases in a sustained manner is lacking, there are generally accepted principles with regard to splinting, bracing, stretching, and surgery that help minimize the impact or disability from contractures.

  15. [Organization of therapeutic aid to patients with hereditary neuromuscular diseases].

    Science.gov (United States)

    Kalinin, V A; Temin, P A; Arkhipov, B A; Zavadenko, N N

    1989-01-01

    The paper summarizes experience gained for many years by the All-Union Research Methodological Center for Study of Hereditary Neuromuscular Diseases. The specialists of the Center render counselling and therapeutic assistance to patients afflicted with neuromuscular diseases. The counselling and diagnostic services are characterized by the fact that it is based on the activity of a large hospital intended for the treatment of various diseases. The problems which are being solved by the out- and inpatient services of the Center are considered in detail. The advantages of the setting up of the common in- and outpatient complex on the basis of the hospital intended for the treatment of various diseases are described.

  16. Efectos del vendaje neuromuscular sobre la flexibilidad del raquis lumbar

    OpenAIRE

    A.M. Labrador-Cerrato; P. Ortega Sánchez-Diezma; G. Lanzas Melendo; Gutiérrez-Ortega, C.

    2015-01-01

    Introducción: El vendaje neuromuscular es una técnica que produce una estimulación muy selectiva sobre la piel a través de la aplicación de unas vendas elásticas especiales con el fin de lograr cambios propioceptivos, aumento o inhibición del tono muscular y mitigación de algias, entre otros. Objetivos: Comprobar si la aplicación del vendaje neuromuscular permite aumentar la flexión del raquis lumbar comparándola con otras técnicas de vendaje placebo (esparadrapo rígido convencional; Omniplas...

  17. Immediate Efficacy of Neuromuscular Exercise in Patients with Severe Osteoarthritis of the Hip or Knee

    DEFF Research Database (Denmark)

    Villadsen, Allan; Overgaard, Søren; Holsgaard-Larsen, Anders

    2014-01-01

    OBJECTIVE: Knowledge about the effects of exercise in severe and endstage osteoarthritis (OA) is limited. The aim was to evaluate the efficacy of a neuromuscular exercise program in patients with clinically severe hip or knee OA. METHODS: This was a randomized controlled assessor-blinded trial...... and Osteoarthritis Outcome Score (HOOS) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. The secondary outcomes were the HOOS/KOOS subscales Pain, Symptoms, Sport and Recreation, and Joint-related Quality of Life. Exploratory outcomes were functional performance measures and lower limb...

  18. The effectiveness of neuromuscular warm-up strategies, that require no additional equipment, for preventing lower limb injuries during sports participation: a systematic review

    Directory of Open Access Journals (Sweden)

    Herman Katherine

    2012-07-01

    Full Text Available Abstract Background Lower limb injuries in sport are increasingly prevalent and responsible for large economic as well as personal burdens. In this review we seek to determine which easily implemented functional neuromuscular warm-up strategies are effective in preventing lower limb injuries during sports participation and in which sporting groups they are effective. Methods Seven electronic databases were searched from inception to January 2012 for studies investigating neuromuscular warm-up strategies and injury prevention. The quality of each included study was evaluated using a modified version of the van Tulder scale. Data were extracted from each study and used to calculate the risk of injury following application of each evaluated strategy. Results Nine studies were identified including six randomized controlled trials (RCT and three controlled clinical trials (CCT. Heterogeneity in study design and warm-up strategies prevented pooling of results. Two studies investigated male and female participants, while the remaining seven investigated women only. Risk Ratio (RR statistics indicated 'The 11+' prevention strategy significantly reduces overall (RR 0.67, confidence interval (CI 0.54 to 0.84 and overuse (RR 0.45, CI 0.28 to 0.71 lower limb injuries as well as knee (RR 0.48, CI 0.32 to 0.72 injuries among young amateur female footballers. The 'Knee Injury Prevention Program' (KIPP significantly reduced the risk of noncontact lower limb (RR 0.5, CI 0.33 to 0.76 and overuse (RR 0.44, CI 0.22 to 0.86 injuries in young amateur female football and basketball players. The 'Prevent Injury and Enhance Performance' (PEP strategy reduces the incidence of anterior cruciate ligament (ACL injuries (RR 0.18, CI 0.08 to 0.42. The 'HarmoKnee' programme reduces the risk of knee injuries (RR 0.22, CI 0.06 to 0.76 in teenage female footballers. The 'Anterior Knee Pain Prevention Training Programme' (AKP PTP significantly reduces the incidence of anterior

  19. Anormalidades neuromuscular no desuso, senilidade e caquexia

    Directory of Open Access Journals (Sweden)

    João Aris Kouyoumdjian

    1993-09-01

    Full Text Available É feita revisão de literatura sobre as principais alterações do sistema neuromuscular no desuso, senilidade e caquexia no ser humano e em modelos animais. A diminuição do diâmetro das fibras musculares após período de inatividade/imobilidade (desuso deve-se à perda de miofibrilas periféricas não ocorrendo formação de core-targetóides ou diminuição da atividade da miofosforilase, próprias da desnervação; mantêm-se a liberação espontânea de acetilcolina e fatores tróficos na junção mio-neural; em geral são afetadas preferencialmente fibras II, que podem assumir forma angular. Existe um processo contínuo intrínseco de envelhecimento de nervos e músculos, com desnervação e reinervação lenta e progressiva; o número de unidades motoras se reduz após 60 anos, sem ocorrência de atividade elétrica desnervatória; a quantidade de acetilcolina liberada nos neurônios terminais e a capacidade máxima de utilização de oxigênio estão diminuídas; a redução da capacidade oxidativa mitocondrial pode explicar o aumento de fibras I, mantendo-se o equilíbrio energético. Após poucas semanas de caquexia as fibras musculares podem ter o diâmetro reduzido em 30%, essa redução ocorre em ordem decrescente nos músculos dos membros inferiores, superiores e tronco; existe atrofia II preferencial com fibras angulares ocasionais, redução de RNA/síntese proteica, mantendo-se DNA normal.

  20. Antimicrobial agents used in the control of periodontal biofilms: effective adjuncts to mechanical plaque control?

    Directory of Open Access Journals (Sweden)

    Ricardo Palmier Teles

    2009-06-01

    Full Text Available The control of biofilm accumulation on teeth has been the cornerstone of periodontal disease prevention for decades. However, the widespread prevalence of gingivitis suggests the inefficiency of self-performed mechanical plaque control in preventing gingival inflammation. This is particularly relevant in light of recent evidence suggesting that long standing gingivitis increases the risk of loss of attachment and that prevention of gingival inflammation might reduce the prevalence of mild to moderate periodontitis. Several antimicrobials have been tested as adjuncts to mechanical plaque control in order to improve the results obtained with oral home care. Recent studies, including meta-analyses, have indicated that home care products containing chemical antimicrobials can provide gingivitis reduction beyond what can be accomplished with brushing and flossing. Particularly, formulations containing chlorhexidine, mouthrinses containing essential oils and triclosan/copolymer dentifrices have well documented clinical antiplaque and antigingivitis effects. In vivo microbiological tests have demonstrated the ability of these antimicrobial agents to penetrate the biofilm mass and to kill bacteria growing within biofilms. In addition, chemical antimicrobials can reach difficult-to-clean areas such as interproximal surfaces and can also impact the growth of biofilms on soft tissue. These agents have a positive track record of safety and their use does not seem to increase the levels of resistant species. Further, no study has been able to establish a correlation between mouthrinses containing alcohol and oral cancer. In summary, the adjunct use of chemical plaque control should be recommended to subjects with well documented difficulties in achieving proper biofilm control using only mechanical means.

  1. Antimicrobial agents used in the control of periodontal biofilms: effective adjuncts to mechanical plaque control?

    Science.gov (United States)

    Teles, Ricardo Palmier; Teles, Flavia Rocha Fonseca

    2009-01-01

    The control of biofilm accumulation on teeth has been the cornerstone of periodontal disease prevention for decades. However, the widespread prevalence of gingivitis suggests the inefficiency of self-performed mechanical plaque control in preventing gingival inflammation. This is particularly relevant in light of recent evidence suggesting that long standing gingivitis increases the risk of loss of attachment and that prevention of gingival inflammation might reduce the prevalence of mild to moderate periodontitis. Several antimicrobials have been tested as adjuncts to mechanical plaque control in order to improve the results obtained with oral home care. Recent studies, including meta-analyses, have indicated that home care products containing chemical antimicrobials can provide gingivitis reduction beyond what can be accomplished with brushing and flossing. Particularly, formulations containing chlorhexidine, mouthrinses containing essential oils and triclosan/copolymer dentifrices have well documented clinical antiplaque and antigingivitis effects. In vivo microbiological tests have demonstrated the ability of these antimicrobial agents to penetrate the biofilm mass and to kill bacteria growing within biofilms. In addition, chemical antimicrobials can reach difficult-to-clean areas such as interproximal surfaces and can also impact the growth of biofilms on soft tissue. These agents have a positive track record of safety and their use does not seem to increase the levels of resistant species. Further, no study has been able to establish a correlation between mouthrinses containing alcohol and oral cancer. In summary, the adjunct use of chemical plaque control should be recommended to subjects with well documented difficulties in achieving proper biofilm control using only mechanical means.

  2. Catalytic Synthesis of Oxygenates: Mechanisms, Catalysts and Controlling Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Klier, Kamil; Herman, Richard G

    2005-11-30

    This research focused on catalytic synthesis of unsymmetrical ethers as a part of a larger program involving oxygenated products in general, including alcohols, ethers, esters, carboxylic acids and their derivatives that link together environmentally compliant fuels, monomers, and high-value chemicals. The catalysts studied here were solid acids possessing strong Brnsted acid functionalities. The design of these catalysts involved anchoring the acid groups onto inorganic oxides, e.g. surface-grafted acid groups on zirconia, and a new class of mesoporous solid acids, i.e. propylsulfonic acid-derivatized SBA-15. The former catalysts consisted of a high surface concentration of sulfate groups on stable zirconia catalysts. The latter catalyst consists of high surface area, large pore propylsulfonic acid-derivatized silicas, specifically SBA-15. In both cases, the catalyst design and synthesis yielded high concentrations of acid sites in close proximity to one another. These materials have been well-characterization in terms of physical and chemical properties, as well as in regard to surface and bulk characteristics. Both types of catalysts were shown to exhibit high catalytic performance with respect to both activity and selectivity for the bifunctional coupling of alcohols to form ethers, which proceeds via an efficient SN2 reaction mechanism on the proximal acid sites. This commonality of the dual-site SN2 reaction mechanism over acid catalysts provides for maximum reaction rates and control of selectivity by reaction conditions, i.e. pressure, temperature, and reactant concentrations. This research provides the scientific groundwork for synthesis of ethers for energy applications. The synthesized environmentally acceptable ethers, in part derived from natural gas via alcohol intermediates, exhibit high cetane properties, e.g. methylisobutylether with cetane No. of 53 and dimethylether with cetane No. of 55-60, or high octane properties, e.g. diisopropylether with

  3. Genetic and evolutionary analysis of the Drosophila larval neuromuscular junction

    Science.gov (United States)

    Campbell, Megan

    Although evolution of brains and behaviors is of fundamental biological importance, we lack comprehensive understanding of the general principles governing these processes or the specific mechanisms and molecules through which the evolutionary changes are effected. Because synapses are the basic structural and functional units of nervous systems, one way to address these problems is to dissect the genetic and molecular pathways responsible for morphological evolution of a defined synapse. I have undertaken such an analysis by examining morphology of the larval neuromuscular junction (NMJ) in wild caught D. melanogaster as well as in over 20 other species of Drosophila. Whereas variation in NMJ morphology within a species is limited, I discovered a surprisingly extensive variation among different species. Compared with evolution of other morphological traits, NMJ morphology appears to be evolving very rapidly. Moreover, my data indicate that natural selection rather than genetic drift is primarily responsible for evolution of NMJ morphology. To dissect underlying molecular mechanisms that may govern NMJ growth and evolutionary divergence, I focused on a naturally occurring variant in D. melanogaster that causes NMJ overgrowth. I discovered that the variant mapped to Mob2, a gene encoding a kinase adapter protein originally described in yeast as a member of the Mitotic Exit Network (MEN). I have subsequently examined mutations in the Drosophila orthologs of all the core components of the yeast MEN and found that all of them function as part of a common pathway that acts presynaptically to negatively regulate NMJ growth. As in the regulation of yeast cytokinesis, these components of the MEN appear to act ultimately by regulating actin dynamics during the process of bouton growth and division. These studies have thus led to the discovery of an entirely new role for the MEN---regulation of synaptic growth---that is separate from its function in cell division. This work

  4. Influência da lidocaína no bloqueio neuromuscular produzido pelo rocurônio: estudo em preparação nervo frênico-diafragma de rato Influencia de la lidocaína en el bloqueo neuromuscular producido por el rocuronio: estudio en preparación nervio frénico-diafragma de ratón Influence of lidocaine on the neuromuscular block produced by rocuronium: study in rat phrenic-diaphragmatic nerve preparation

    Directory of Open Access Journals (Sweden)

    Yolanda Christina S. Loyola

    2006-04-01

    el antagonismo parcial de neostigmina.BACKGROUND AND OBJECTIVES: The action mechanism of local anesthetics (LA on neuromuscular junction motivated several studies. When administered at low doses, they do not interfere on neuromuscular transmission. But high doses may compromise neuromuscular transmission and increase the effects of neuromuscular blockers. The objective of this study was to evaluate lidocaine interaction with rocuronium on rat diaphragm through its influence on neuromuscular block degree. METHODS: Rats, weighing between 250 and 300 g, were used. Preparation was set according to the technique described by Bulbring. Groups were formed (n = 5 according to the drug being studied: lidocaine - 20 µg.mL-1 (Group I; rocuronium - 4 µg.mL-1 (Group II, and rocuronium - 4 µg.mL-1 with lidocaine - 20 µg.mL-1 (Group III. The following items were assessed: 1 the extent of diaphragm muscle responses to indirect stimulation, both before and 60 minutes after adding lidocaine and a neuromuscular blocker; 2 membrane potentials (MP and miniature end-plate potentials (MEPP; 3 the effectiveness of neostigmine, and 4 aminopyridine on neuromuscular blockage reversal. RESULTS: When administered separately, lidocaine did not alter the extent of muscular responses. With the previous use of lidocaine, rocuronium neuromuscular blockage was 82.8% ± 1.91%, with a significant difference (p = 0.0079 when compared to the group with isolated rocuronium (57.8% ± 1.9%. Blockage was both partially and fully reverted by neostigmine and 4-aminopyridine, respectively. Lidocaine did not alter membrane potential and caused an initial increase on MEPP, followed by a blockage. CONCLUSIONS: Lidocaine increases the neuromuscular blocking produced by rocuronium. MEPP modifications identify a presynaptic action. The complete antagonism of 4-aminopyridine indicates a presynaptic component. This idea is supported by the partial antagonism through neostigmine.

  5. Adrenergic receptor control mechanism for growth hormone secretion.

    Science.gov (United States)

    Blackard, W G; Heidingsfelder, S A

    1968-06-01

    The influence of catecholamines on growth hormone secretion has been difficult to establish previously, possibly because of the suppressive effect of the induced hyperglycemia on growth hormone concentrations. In this study, an adrenergic receptor control mechanism for human growth hormone (HGH) secretion was uncovered by studying the effects of alpha and beta receptor blockade on insulin-induced growth hormone elevations in volunteer subjects. Alpha adrenergic blockade with phentolamine during insulin hypoglycemia, 0.1 U/kg, inhibited growth hormon elevations to 30-50% of values in the same subjects during insulin hypoglycemia without adrenergic blockade. More complete inhibition by phentolamine could not be demonstrated at a lower dose of insulin (0.05 U/kg). Beta adrenergic blockade with propranolol during insulin hypoglycemia significantly enhanced HGH concentrations in paired experiments. The inhibiting effect of alpha adrenergic receptor blockade on HGH concentrations could not be attributed to differences in blood glucose or free fatty acid values; however, more prolonged hypoglycemia and lower plasma free fatty acid values may have been a factor in the greater HGH concentrations observed during beta blockade. In the absence of insulin induced hypoglycemia, neither alpha nor beta adrenergic receptor blockade had a detectable effect on HGH concentrations. Theophylline, an inhibitor of cyclic 3'5'-AMP phosphodiesterase activity, also failed to alter plasma HGH concentrations. These studies demonstrate a stimulatory effect of alpha receptors and a possible inhibitory effect of beta receptors on growth hormone secretion.

  6. Controlled growth mechanism of poly (3-hexylthiophene) nanowires

    Science.gov (United States)

    Kiymaz, D.; Yagmurcukardes, M.; Tomak, A.; Sahin, H.; Senger, R. T.; Peeters, F. M.; Zareie, H. M.; Zafer, C.

    2016-11-01

    Synthesis of 1D-polymer nanowires by a self-assembly method using marginal solvents is an attractive technique. While the formation mechanism is poorly understood, this method is essential in order to control the growth of nanowires. Here we visualized the time-dependent assembly of poly (3-hexyl-thiophene-2,5-diyl) (P3HT) nanowires by atomic force microscopy and scanning tunneling microscopy. The assembly of P3HT nanowires was carried out at room temperature by mixing cyclohexanone (CHN), as a poor solvent, with polymer solution in 1,2-dichlorobenzene (DCB). Both π-π stacking and planarization, obtained at the mix volume ratio of P3HT (in DCB):CHN (10:7), were considered during the investigation. We find that the length of nanowires was determined by the ordering of polymers in the polymer repetition direction. Additionally, our density functional theory calculations revealed that the presence of DCB and CHN molecules that stabilize the structural distortions due to tail group of polymers was essential for the core-wire formation.

  7. Controlling mechanisms of moisture diffusion in convective drying of leather

    Science.gov (United States)

    Benmakhlouf, Naima; Azzouz, Soufien; Monzó-Cabrera, Juan; Khdhira, Hechmi; ELCafsi, Afif

    2016-08-01

    Leather manufacturing involves a crucial energy-intensive drying stage in the finishing process to remove its residual moisture. It occurs several times in the tanning course. As it is the target of this paper to depict an experimental way to determine moisture diffusion in the convective drying of leather. The effective diffusion coefficient is estimated by a method derived from Fick's law and by analytic method. The effective diffusion coefficients are obtained from drying tests and the diffusivity behaviour is studied versus the controlling parameter such as the convective airflow temperature. The experiments were conducted at hot air temperatures of 40, 45, 50, 55 and 60 °C and hot air speed of 1 m/s. The hot air temperature had significant effect on the effective moisture diffusivity of the leather sample. The average effective moisture diffusivity in rosehip ranged between 5.87 × 10-11 and 14.48 × 10-11 m2/s for leather at the temperatures studied. Activation energy for convective drying was found to be 38.46 kJ/mol for leather. The obtained results fully confirm the theoretical study in which an exponentially increasing relationship between effective diffusivity and temperature is predicted. The results of this study provide a better understanding of the drying mechanisms and may lead to a series of recommendations for leather drying optimization. It opens the possibility for further investigations on the description of drying conditions.

  8. Immunosensor with fluid control mechanism for salivary cortisol analysis.

    Science.gov (United States)

    Yamaguchi, Masaki; Matsuda, Yohei; Sasaki, Shohei; Sasaki, Makoto; Kadoma, Yoshihiro; Imai, Yoshikatsu; Niwa, Daisuke; Shetty, Vivek

    2013-03-15

    The purpose of this research is to demonstrate a new design for a cortisol immunosensor for the noninvasive and quantitative analysis of salivary cortisol. We propose a cortisol immunosensor with a fluid control mechanism which has both a vertical flow and a lateral flow. The detected current resulting from a competitive reaction between the sample cortisol and a glucose oxidase (GOD)-labeled cortisol conjugate was found to be inversely related to the concentration of cortisol in the sample solution. A calibration curve using the relative detected current showed a R(2)=0.98 and CV=14% for a range of standard cortisol solutions corresponding to the concentrations of native salivary cortisol (0.1-10 ng/ml). The measurement could be accomplished within 35 min and the cortisol immunosensor could be reused. These results show promise for realizing an on-site and easy-to-use biosensor for cortisol. Used for evaluation of human salivary cortisol levels, the cortisol immunosensor measurement corresponded closely with commercially available ELISA method (R(2)=0.92). Our results indicate the promise of the new cortisol immunosensor for noninvasive, point of care measurement of human salivary cortisol levels.

  9. Weathering controls on mechanisms of carbon storage in grassland soils

    Energy Technology Data Exchange (ETDEWEB)

    Masiello, C.A.; Chadwick, O.A.; Southon, J.; Torn, M.S.; Harden, J.W.

    2004-09-01

    On a sequence of soils developed under similar vegetation, temperature, and precipitation conditions, but with variations in mineralogical properties, we use organic carbon and 14C inventories to examine mineral protection of soil organic carbon. In these soils, 14C data indicate that the creation of slow-cycling carbon can be modeled as occurring through reaction of organic ligands with Al3+ and Fe3+ cations in the upper horizons, followed by sorption to amorphous inorganic Al compounds at depth. Only one of these processes, the chelation of Al3+ and Fe3+ by organic ligands, is linked to large carbon stocks. Organic ligands stabilized by this process traverse the soil column as dissolved organic carbon (both from surface horizons and root exudates). At our moist grassland site, this chelation and transport process is very strongly correlated with the storage and long-term stabilization of soil organic carbon. Our 14C results show that the mechanisms of organic carbon transport and storage at this site follow a classic model previously believed to only be significant in a single soil order (Spodosols), and closely related to the presence of forests. The presence of this process in the grassland Alfisol, Inceptisol, and Mollisol soils of this chronosequence suggests that this process is a more significant control on organic carbon storage than previously thought.

  10. Distinct neural and neuromuscular strategies underlie independent evolution of simplified advertisement calls.

    Science.gov (United States)

    Leininger, Elizabeth C; Kelley, Darcy B

    2013-04-07

    Independent or convergent evolution can underlie phenotypic similarity of derived behavioural characters. Determining the underlying neural and neuromuscular mechanisms sheds light on how these characters arose. One example of evolutionarily derived characters is a temporally simple advertisement call of male African clawed frogs (Xenopus) that arose at least twice independently from a more complex ancestral pattern. How did simplification occur in the vocal circuit? To distinguish shared from divergent mechanisms, we examined activity from the calling brain and vocal organ (larynx) in two species that independently evolved simplified calls. We find that each species uses distinct neural and neuromuscular strategies to produce the simplified calls. Isolated Xenopus borealis brains produce fictive vocal patterns that match temporal patterns of actual male calls; the larynx converts nerve activity faithfully into muscle contractions and single clicks. In contrast, fictive patterns from isolated Xenopus boumbaensis brains are short bursts of nerve activity; the isolated larynx requires stimulus bursts to produce a single click of sound. Thus, unlike X. borealis, the output of the X. boumbaensis hindbrain vocal pattern generator is an ancestral burst-type pattern, transformed by the larynx into single clicks. Temporally simple advertisement calls in genetically distant species of Xenopus have thus arisen independently via reconfigurations of central and peripheral vocal neuroeffectors.

  11. Mechanical Engineering Design Project report: Enabler control systems

    Science.gov (United States)

    Cullen, Christian; Delvecchio, Dave; Scarborough, Alan; Havics, Andrew A.

    1992-01-01

    The Controls Group was assigned the responsibility for designing the Enabler's control system. The requirement for the design was that the control system must provide a simple user interface to control the boom articulation joints, chassis articulation joints, and the wheel drive. The system required controlling hydraulic motors on the Enabler by implementing 8-bit microprocessor boards. In addition, feedback to evaluate positions and velocities must be interfaced to provide the operator with confirmation as well as control.

  12. Optimising abdominal space with deep neuromuscular blockade in gynaecologic laparoscopy

    DEFF Research Database (Denmark)

    Madsen, Matias Vested; Gätke, M R; Springborg, H H

    2015-01-01

    neuromuscular blockade (NMB) would enlarge surgical space, measured as the distance from the sacral promontory to the trocar in patients undergoing gynaecologic laparoscopy. METHODS: Fourteen patients were randomised in an assessor-blinded crossover design. The distance from the sacral promontory to the trocar...

  13. Is deep neuromuscular blockade beneficial in laparoscopic surgery?

    DEFF Research Database (Denmark)

    Madsen, M V; Staehr-Rye, A K; Claudius, C;

    2016-01-01

    BACKGROUND: Deep neuromuscular blockade during laparoscopic surgery may provide some clinical benefit. We present the 'Pro-' argument in this paired position paper. METHODS: We reviewed recent evidence from a basic database of references which we agreed on with the 'Con-' side, and present this i...

  14. Drug Development and Challenges for Neuromuscular Clinical Trials.

    Science.gov (United States)

    El Mouelhi, Mohamed

    2016-03-01

    Drug development process faces many challenges, including those encountered in clinical trials for neuromuscular diseases. Drug development is a lengthy and highly costly process. Out of 10 compounds entering first study in man (phase 1), only one compound reaches the market after an average of 14 years with a cost of $2.7 billion. Nevertheless, according to the Centers for Medicare and Medicaid services, prescription drugs constituted only 9 % of each health care dollar spent in USA in 2013. Examples of challenges encountered in neuromuscular clinical trials include lack of validated patient-reported outcome tools, blinding issues, and the use of placebo in addition to lack of health authority guidance for orphan diseases. Patient enrollment challenge is the leading cause of missed clinical trial deadlines observed in about 80 % of clinical trials, resulting in delayed availability of potentially life-saving therapies. Another specific challenge introduced by recent technology is the use of social media and risk of bias. Sharing personal experiences while in the study could easily introduce bias among patients that would interfere with accurate interpretation of collected data. To minimize this risk, recent neuromuscular studies incorporate as an inclusion criterion the patient's agreement not to share any of study experiences through social media with other patients during the study conduct. Consideration of these challenges will allow timely response to the high unmet medical needs for many neuromuscular diseases.

  15. Neuromuscular Bandage: Neurophysiological Effects and the Role of Fascias

    Directory of Open Access Journals (Sweden)

    Ximena María Villota Chicaíza

    2014-05-01

    Full Text Available During the last years, neuromuscular bandage, a therapeutic application created in 1979 by doctor Kenzo Kase has been introduced in the management of many disorders of the musculo-skeletal system and even more so in the treatment of neurological disorders; This therapeutic tool which consists of a self adhesive elastic bandage allows recovery of the injured party without diminishing its bodily function. According to the existing literature on the physiological effects of this therapeutic application in the body, you could say that there is consensus. However in this article the author wants to highlight the significant although little highlighted role played by the fas¬cias on the therapeutic effects of neuromuscular bandage, analyzing from a reflective perspective the analgesic, neuromechanical and circulatory effects, as fundamental effects of neuromuscular bandage and fascias in the same function, trying to bring a global understanding on the way they relate to all connective tissues, aspects that are of great importance for the proper evaluation of alterations and prescription of neuromuscular bandage

  16. Muscle ultrasound quantifies segmental neuromuscular outcome in pediatric myelomeningocele

    NARCIS (Netherlands)

    Verbeek, Renate J; Hoving, Eelco; Maurits, Natalia M; Brouwer, Oebele F; van der Hoeven, Johannes H; Sival, Deborah A

    2014-01-01

    In pediatric spina bifida aperta (SBA), non-invasive assessment of neuromuscular integrity by muscle ultrasound density (MUD) could provide important information about the clinical condition. We therefore aimed to determine the association between pediatric SBA MUD and segmental neurologic function.

  17. Tortuosity and anomalous diffusion in the neuromuscular junction

    Science.gov (United States)

    Lacks, Daniel J.

    2008-04-01

    The signal transfer from nerve to muscle occurs by diffusion across the neuromuscular junction. The continuum level analysis of diffusion processes is based on the diffusion equation, which in one dimension is ∂c/∂t=D(∂2c/∂x2) , where c is the molecular concentration and D is the diffusivity. However, in confined systems such as the neuromuscular junction, the diffusion equation may not be valid, and even if valid the value of D may be altered by the confinement. In this paper, Monte Carlo simulations are used to probe diffusion at the molecular level in a realistic model of a neuromuscular junction. The results show that diffusion is anomalous (i.e., not described by the diffusion equation) for time scales less than ˜0.01s , which is the time scale relevant for signaling processes in the synapse. At longer time scales, the diffusion is normal (i.e., described by the diffusion equation), but with a value of D that is reduced by a factor of ˜5 times compared to the value for diffusion in open space. As the width of the synaptic cleft decreases, these effects become even more pronounced. The physical basis of these results is described in terms of the structure of the neuromuscular junction.

  18. Antagonism of non-depolarising neuromuscular block: current practice.

    Science.gov (United States)

    Kopman, A F; Eikermann, M

    2009-03-01

    There is now mounting evidence that even small degrees of postoperative residual neuromuscular block increases the incidence of adverse respiratory events in the Post Anaesthesia Care Unit and may increase longer-term morbidity as well. In the absence of quantitative neuromuscular monitoring, residual block is easily missed. A very strong case can be made for the routine administration of a non-depolarising antagonist unless it can be objectively demonstrated that complete recovery has occurred spontaneously. However, the use of acetylcholinesterase inhibitors is associated with the potential for cardiovascular and respiratory side-effects, so there are cogent reasons for using low doses when the level of neuromuscular block is not intense. As little as 0.015-0.025 mg.kg(-1) of neostigmine is required at a train-of-four count of four with minimal fade, whereas 0.04-0.05 mg.kg(-1) is needed at a train-of-four count of two or three. If only a single twitch or none at all can be evoked, neostigmine should not be expected to promptly reverse neuromuscular block, and antagonism is best delayed till a train-of-four-count of two is achieved.

  19. Volume of the effect compartment in simulations of neuromuscular block

    NARCIS (Netherlands)

    Nigrovic, Vladimir; Proost, Johannes H.; Amann, Anton; Bhatt, Shashi B.

    2005-01-01

    Background: The study examines the role of the volume of the effect compartment in simulations of neuromuscular block (NMB) produced by nondepolarizing muscle relaxants. Methods: The molar amount of the postsynaptic receptors at the motor end plates in muscle was assumed constant; the apparent recep

  20. Disentangling the Impact of Control-Enhancing Mechanisms on Firm Performance

    DEFF Research Database (Denmark)

    Zattoni, Alessandro; Pedersen, Torben

    2011-01-01

    Governance scholars and investors traditionally advocate against the use of control enhancing mechanisms, i.e. mechanisms aimed at separating voting and cash flow rights. These mechanisms may, in fact, determine a deviation from the proportionality principle and may encourage large and controlling......, and (ii) the negative impact on firm performance of mechanisms aimed at enhancing control by leveraging voting power is mediated by the divergence in voting and cash flow rights....

  1. Therapeutic effect and mechanism of neuromuscular facilitation techniques in treatment of hemiplegic stroke patients'osteoporosis%神经肌肉促进技术对脑卒中后偏瘫患者肢体骨质疏松的疗效及作用机制

    Institute of Scientific and Technical Information of China (English)

    贾立坤; 王聪聪; 李秀华; 张秀清

    2014-01-01

    目的:通过检测脑卒中后偏瘫患者的骨密度( BMD )及血清瘦素( LP )、碱性磷酸酶( ALP )、骨钙素(BGP)、白介素-6(IL-6)水平,观察神经肌肉促进技术(NFT)对其肢体骨质疏松的影响。方法将52例脑卒中偏瘫患者随机分为治疗组和对照组,对照组行常规治疗,治疗组在常规治疗基础上早期给予NFT治疗。采用双能X线吸收法检测两组入院第2天及治疗6个月后的BMD,采用ELISA法检测两组血清LP、ALP、BGP、IL-6水平,并进行比较。结果6个月后两组患肢BMD、对照组健肢与患肢BMD比较差异均有统计学意义(P均<0.05);两组血清LP、ALP、BGP、IL-6水平比较差异均有统计学意义(P<0.05或<0.01)。结论 NFT能影响脑卒中后偏瘫患者骨代谢指标,增加偏瘫肢体BMD;NFT对防治脑卒中后偏瘫患者的骨质疏松有效。%Objective To observe the therapeutic effect of neuromuscular facilitation techniques (NFT) on hemiplegic stroke patients'osteoporosis through the detections of serum leptin (LP), alkaline phosphatase (ALP), bone gla-protein (BGP), interleukin-6 (IL-6) and bone mineral density (BMD).Methods Fifty-two hemiplegic stroke patients were randomly divided into 2 groups:the control group which received conventional treatment, and the treatment group which received NFT early be-sides conventional treatment.The serum LP, ALP, BGP, IL-6 and BMD of all cases in the second day of admission and 6 months after the treatment were detected by using ELISA method and double X-ray absorption method, and then contrastive analysis was conducted.Results The BMD of hemiplegic limbs between the two groups 6 months later, and the BMD between the hemiplegic limbs and the healthy limbs in the control group 6 months later all had statistically significant differences (all P<0.05).The se-rum ALP, BGP, IL-6 and LP levels 6 months later all had statistically significant differences

  2. Neuromuscular Activity of Micrurus laticollaris (Squamata: Elapidae Venom in Vitro

    Directory of Open Access Journals (Sweden)

    Alejandro Carbajal-Saucedo

    2014-01-01

    Full Text Available In this work, we have examined the neuromuscular activity of Micrurus laticollaris (Mexican coral snake venom (MLV in vertebrate isolated nerve-muscle preparations. In chick biventer cervicis preparations, the MLV induced an irreversible concentration- and time-dependent (1–30 µg/mL neuromuscular blockade, with 50% blockade occurring between 8 and 30 min. Muscle contractures evoked by exogenous acetylcholine were completely abolished by MLV, whereas those of KCl were also significantly altered (86% ± 11%, 53% ± 11%, 89% ± 5% and 89% ± 7% for one, three, 10 and 30 µg of venom/mL, respectively; n = 4; p < 0.05. In mouse phrenic nerve-diaphragm preparations, MLV (1–10 µg/mL promoted a slight increase in the amplitude of twitch-tension (3 µg/mL, followed by neuromuscular blockade (n = 4; the highest concentration caused complete inhibition of the twitches (time for 50% blockade = 26 ± 3 min, without exhibiting a previous neuromuscular facilitation. The venom (3 µg/mL induced a biphasic modulation in the frequency of miniature end-plate potentials (MEPPs/min, causing a significant increase after 15 min, followed by a decrease after 60 min (from 17 ± 1.4 (basal to 28 ± 2.5 (t15 and 12 ± 2 (t60. The membrane resting potential of mouse diaphragm preparations pre-exposed or not to d-tubocurarine (5 µg/mL was also significantly less negative with MLV (10 µg/mL. Together, these results indicate that M. laticollaris venom induces neuromuscular blockade by a combination of pre- and post-synaptic activities.

  3. Assessment of ventilatory neuromuscular drive in patients with obstructive sleep apnea

    Directory of Open Access Journals (Sweden)

    L.R.A. Bittencourt

    1998-04-01

    Full Text Available The presence of abnormalities of the respiratory center in obstructive sleep apnea (OSA patients and their correlation with polysomnographic data are still a matter of controversy. Moderately obese, sleep-deprived OSA patients presenting daytime hypersomnolence, with normocapnia and no clinical or spirometric evidence of pulmonary disease, were selected. We assessed the ventilatory control and correlated it with polysomnographic data. Ventilatory neuromuscular drive was evaluated in these patients by measuring the ventilatory response (VE, the inspiratory occlusion pressure (P.1 and the ventilatory pattern (VT/TI, TI/TTOT at rest and during submaximal exercise, breathing room air. These analyses were also performed after inhalation of a hypercapnic mixture of CO2 (DP.1/DPETCO2, DVE/DPETCO2. Average rest and exercise ventilatory response (VE: 12.2 and 32.6 l/min, respectively, inspiratory occlusion pressure (P.1: 1.5 and 4.7 cmH2O, respectively, and ventilatory pattern (VT/TI: 0.42 and 1.09 l/s; TI/TTOT: 0.47 and 0.46 l/s, respectively were within the normal range. In response to hypercapnia, the values of ventilatory response (DVE/DPETCO2: 1.51 l min-1 mmHg-1 and inspiratory occlusion pressure (DP.1/DPETCO2: 0.22 cmH2O were normal or slightly reduced in the normocapnic OSA patients. No association or correlation between ventilatory neuromuscular drive and ventilatory pattern, hypersomnolence score and polysomnographic data was found; however a significant positive correlation was observed between P.1 and weight. Our results indicate the existence of a group of normocapnic OSA patients who have a normal awake neuromuscular ventilatory drive at rest or during exercise that is partially influenced by obesity

  4. Direct and indirect measurement of neuromuscular fatigue in Canadian football players.

    Science.gov (United States)

    Clarke, Nick; Farthing, Jonathan P; Lanovaz, Joel L; Krentz, Joel R

    2015-05-01

    This study assessed the effects of a fatiguing game simulation (G-Sim) on the balance of collegiate Canadian football players. The purpose of the study was to evaluate postural control as a potential tool for monitoring neuromuscular fatigue (NMF) in collision-based team sports. Fifteen male Canadian football players were recruited (mean±SD: age 21.8±1.6 years, weight 97.6±14.7 kg). Indirect NMF measures (postural sway and countermovement jump (CMJ)) were performed 24 h before (TBase), immediately before (TPre) and after (TPost), and 24 h (T24) and 48 h after (T48) a Canadian football G-Sim. Peak isometric knee extensor torque of a maximal voluntary contraction (MVC) and electrically evoked tetani at 20 Hz (P20) and 80 Hz (P80) were also recorded as direct NMF measures at TBase, TPre, TPost, and T48. At TPost, we observed significant declines in MVC, P20, and the MVC/P80 ratio (-15.3%, -15.7%, and -12.1%, respectively; n=12) along with reductions in CMJ takeoff velocity and peak power (-6.9% and -6.5%, respectively; n=12) and larger area of the center of pressure trajectory (95.2%; n=10) during a 60-s postural sway task. All variables were no longer different than baseline by T48. Acute neuromuscular impairment in this cohort is likely attributable to alterations in excitation-contraction coupling due to structural damage and central activation failure. Congruency between the direct and indirect measures of NMF suggests monitoring postural sway has the potential to identify both neuromuscular and somatosensory alterations induced by acute game-induced fatigue in collision-based team sports players.

  5. Do Psychosocial Interventions Improve Quality of Life and Wellbeing in Adults with Neuromuscular Disorders? A Systematic Review and Narrative Synthesis.

    Science.gov (United States)

    Walklet, Elaine; Muse, Kate; Meyrick, Jane; Moss, Tim

    2016-08-30

    Quality of life and well-being are frequently restricted in adults with neuromuscular disorders. As such, identification of appropriate interventions is imperative. The objective of this paper was to systematically review and critically appraise quantitative studies (RCTs, controlled trials and cohort studies) of psychosocial interventions designed to improve quality of life and well-being in adults with neuromuscular disorders. A systematic review of the published and unpublished literature was conducted. Studies meeting inclusion criteria were appraised using a validated quality assessment tool and results presented in a narrative synthesis. Out of 3,136 studies identified, ten studies met criteria for inclusion within the review. Included studies comprised a range of interventions including: cognitive behavioural therapy, dignity therapy, hypnosis, expressive disclosure, gratitude lists, group psychoeducation and psychologically informed rehabilitation. Five of the interventions were for patients with Amyotrophic Lateral Sclerosis (ALS). The remainder were for patients with post-polio syndrome, muscular dystrophies and mixed disorders, such as Charcot-Marie-Tooth disease, myasthenia gravis and myotonic dystrophy. Across varied interventions and neuromuscular disorders, seven studies reported a short-term beneficial effect of intervention on quality of life and well-being. Whilst such findings are encouraging, widespread issues with the methodological quality of these studies significantly compromised the results. There is no strong evidence that psychosocial interventions improve quality of life and well-being in adults with neuromuscular disorders, due to a paucity of high quality research in this field. Multi-site, randomised controlled trials with active controls, standardised outcome measurement and longer term follow-ups are urgently required.

  6. Development of an Outdoor Temperature-Based Control Algorithm for Residential Mechanical Ventilation Control

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tang, Yihuan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-06-01

    Smart ventilation systems use controls to ventilate more during those periods that provide either an energy or IAQ advantage (or both) and less during periods that provide a dis advantage. Using detailed building simulations, this study addresses one of the simplest and lowest cost types of smart controllers —outdoor temperature- based control. If the outdoor temperature falls below a certain cut- off, the fan is simply turned off. T he main principle of smart ventilation used in this study is to shift ventilation from time periods with large indoor -outdoor temperature differences, to periods where these differences are smaller, and their energy impacts are expected to be less. Energy and IAQ performance are assessed relative to a base case of a continuously operated ventilation fan sized to comply with ASHRAE 62.2-2013 whole house ventilation requirements. In order to satisfy 62.2-2013, annual pollutant exposure must be equivalent between the temperature controlled and continuous fan cases. This requires ventilation to be greater than 62.2 requirements when the ventilation system operates. This is achieved by increasing the mechanical ventilation system air flow rates.

  7. Effects of Dynamic Neuromuscular Analysis Training on Static and Dynamic Balance in Indian Female Basketball Players

    Directory of Open Access Journals (Sweden)

    Archna Sharma

    2013-04-01

    Full Text Available The aim of this paper was to investigate the effects of dynamic neuromuscular analysis on static and dynamic balance of Indian state level female athletes. It was hypothesized that the training protocol would improve both static and dynamic components of the balance, improving dynamic balance more than static. A total of 43 randomly selected state level female basketball players aged 16 -18 years participated in the study. The subjects were further divided into two groups, viz. Dynamic Neuromuscular Analysis (DNA group (n=23 and control group (n = 20. Pre and post static balance was tested to all the subjects by Stork Balance Test (SBT and Balance Error Scoring System (BESS, and dynamic balance was measured by Star Excursion Balance Test (SEBT. DNA intervention of 90 minutes was given for 6 weeks while the control group followed traditional training. Results showed a significant improvement both in static and dynamic balance (p<0.001. It might be concluded that 6 week DNA training designed for the prevention of ACL injuries could also improve both static and dynamic balance in Indian female basketball players.

  8. Neuromuscular electrical stimulation for mobility support of elderly

    Directory of Open Access Journals (Sweden)

    Winfried Mayr

    2015-10-01

    Full Text Available The stimulator for neuromuscular electrical stimulation for mobility support of elderly is not very complicated, but for application within "MOBIL" we have some additional demands to fulfill. First we have specific safety issues for this user group. A powerful compliance management system is crucial not only to guide daily application, but for creating hard data for the scientific outcome. We also need to assure easy handling of the stimulator, because the subjects are generally not able to cope with too difficult and complex motor skills. So, we developed five generations of stimulators and optimizing solutions after field tests. We are already planning the sixth generation with wireless control of the stimulation units by the central main handheld control unit. In a prototype, we have implemented a newly available high capacity memory, a breakthrough in “compliance data storage” as they offer the necessary high storage capacity and fast data handling for an affordable prize. The circuit also contains a 3D accelerometer sensor which acts as a further important safety features: if the control unit drops, this event is detected automatically by the sensor and activates an emergency switch-off that disables the stimulation to avoid associated risks. Further, we have implemented a hardware emergence shutdown and other safety measures. Finally, in the last example muscle torque measurements are referenced with compliance data. In the study normalized maximum voluntary contraction (MVC and maximum stimulation induced contraction (MSC were assessed in regular check-ups along the training period. With additional consideration of adjusted stimulation intensity for training out of the compliance data records we are able to estimate the induced contraction strength, which turned out to amount in average 11% of MVC. This value may seem on a first sight rather low, and ought to be considered in relation to the results at the end of the training period

  9. Detecção de fadiga neuromuscular em pessoas com lesão medular completa utilizando transformada wavelet

    OpenAIRE

    Krueger,Eddy

    2014-01-01

    Introdução: As pessoas com lesão medular (LM) podem ter seus músculos paralisados ativados por meio da estimulação elétrica funcional (FES) sobre vias neurais presentes próximas à pele. Estas estimulações elétricas são importantes para a recuperação do trofismo neuromuscular ou durante o controle de movimento por próteses neurais. No entanto, ao longo da aplicação da FES, a fadiga ocorre, diminuindo a eficiência da contração, principalmente devido à hipotrofia neuromuscular presente nessa pop...

  10. Matlab/simMechanics based control of four-bar passive lower-body mechanism for rehabilitation

    Directory of Open Access Journals (Sweden)

    Ashish Singla

    2016-09-01

    Full Text Available In recent times, use of wearable devices is becoming popular for providing precise ways of rehabilitation. The focus of this paper is to propose a passive lower body mechanism using a four-bar linkage, which can be actuated via the hip joint to move the other two joints at knee and ankle as well. Simulations are performed here by considering an average male human (height six feet by modelling the gait cycle in CAD software and executing the control strategy in the SimMechanics, which provides a convenient way to study without use of detailed computational mathematics. The study of the controller aspects of the passive mechanism is presented with both PD and PID controllers with auto- and manual-tuned gains. Significant reduction in actuator torques is observed with the manually-tuned PID controller over automatically-tuned PID controller with marginal degradation in the overshoot and settling time.

  11. EFEITO DO TREINO NEUROMUSCULAR NA ROTAÇÃO DO JOELHO DURANTE A ATERRISSAGEM EM MULHERES

    Directory of Open Access Journals (Sweden)

    Narayana Vianna Spanó

    2016-04-01

    Full Text Available Introdução: O grande índice de lesões do ligamento cruzado anterior sem envolver contato em mulheres é motivo de curiosidade entre os cientistas, pois avaliações de aterrissagem podem sugerir a predisposição ao risco dessa lesão. Neste sentido, vários protocolos de treinamento foram utilizados como intervenção e obtiveram resultados diversificados na alteração desse fator de risco. Objetivo: O objetivo deste projeto foi avaliar as possíveis alterações de rotação do joelho na aterrissagem unipodal após a intervenção de um programa de treinamento neuromuscular. Métodos: Participaram do estudo 18 mulheres com idade entre 18 e 51 anos, que foram distribuídas em dois grupos: grupo de treinamento neuromuscular de oito semanas (GTN (n = 11 e grupo controle (GC (n = 7. Além disso, não apresentavam lesão musculoesquelética ou dores nos membros inferiores. Cada participante realizou cinco aterrissagens unipodais válidas de uma plataforma de 40 cm de altura. O processo de captura de movimento foi realizado com 12 câmeras infravermelho do sistema OptiTrack(tm para obter as coordenadas tridimensionais de marcadores fixados nos pontos anatômicos de interesse. Os sistemas de coordenadas locais da coxa e da perna foram definidos por meio dos respectivos marcadores fixados nos pontos anatômicos. Dessa forma, foram calculados os ângulos de rotação do joelho nos planos sagital, frontal e transverso através das sequências dos ângulos de Euler e as velocidades angulares através das formulações dos quatérnions. Resultados: Os resultados mostraram que houve um aumento na velocidade de rotação do joelho após o treinamento neuromuscular. Conclusão: Conclui-se que o treinamento neuromuscular resultou em maior velocidade de rotação no joelho nos 40 milissegundos que sucedem a aterrissagem unipodal.

  12. Compound control strategy used in Electro-Mechanical Actuator (EMA)

    Science.gov (United States)

    Fu, Yongling; Yan, Meng

    2017-01-01

    This article briefly describes the overall structure of the loading test rig; establish mathematical model of loading EMA, analyze its stability, surplus force and other properties in MATLAB; propose a compound control strategy combined speed feedback, PID and feed-forward compensation based on structure invariance principle. To verify the effectiveness of the control strategy, do a co-simulation by designing a controller based on the control strategy above in MATLAB and building the EMA model in AMESim. The results show that the compound control strategy can significantly improve dynamic tracking accuracy and reduce surplus force.

  13. Chronic respiratory failure in patients with neuromuscular diseases: diagnosis and treatment.

    Science.gov (United States)

    Paschoal, Ilma Aparecida; Villalba, Wander de Oliveira; Pereira, Mônica Corso

    2007-01-01

    Neuromuscular diseases affect alveolar air exchange and therefore cause chronic respiratory failure. The onset of respiratory failure can be acute, as in traumas, or progressive (slow or rapid), as in amyotrophic lateral sclerosis, muscular dystrophies, diseases of the myoneural junction, etc. Respiratory muscle impairment also affects cough efficiency and, according to the current knowledge regarding the type of treatment available in Brazil to these patients, it can be said that the high rates of morbidity and mortality in these individuals are more often related to the fact that they cough inefficiently rather than to the fact that they ventilate poorly. In this review, with the objective of presenting the options of devices available to support and substitute for natural ventilation in patients with neuromuscular diseases, we have compiled a brief history of the evolution of orthopedic braces and prostheses used to aid respiration since the end of the 19th century. In addition, we highlight the elements that are fundamental to the diagnosis of alveolar hypoventilation and of failure of the protective cough mechanism: taking of a clinical history; determination of peak cough flow; measurement of maximal inspiratory and expiratory pressures; spirometry in two positions (sitting and supine); pulse oximetry; capnography; and polysomnography. Furthermore, the threshold values available in the literature for the use of nocturnal ventilatory support and for the extension of this support through the daytime period are presented. Moreover, the maneuvers used to increase cough efficiency, as well as the proper timing of their introduction, are discussed.

  14. Neuromuscular responses to mild-muscle damaging eccentric exercise in a low glycogen state.

    Science.gov (United States)

    Gavin, James P; Myers, Stephen D; Willems, Mark E T

    2015-02-01

    The aim of this study was to examine the effect of low muscle glycogen on the neuromuscular responses to maximal eccentric contractions. Fourteen healthy men (22 ± 3 years) performed single-leg cycling (20 min at ~75% maximal oxygen uptake (V̇O2 max); eight 90 s sprints at a 1:1 work-to-rest ratio (5% decrements from 90% to 55% V̇O2 max until exhaustion) the evening before 100 eccentric (1.57 rads(-1)) with reduced (RED) and normal glycogen (NORM). Neuromuscular responses were measured during and up to 48 h after with maximal voluntary and involuntary (twitch, 20 Hz and 50 Hz) isometric contractions. During eccentric contractions, peak torque decreased (RED: -16.1 ± 2.5%; NORM: -6.2 ± 5.1%) and EMG frequency increased according to muscle length. EMG activity decreased for RED only. After eccentric contractions, maximal isometric force was reduced up to 24h for NORM (-13.5 ± 5.8%) and 48 h for RED (-7.4 ± 10.9%). Twelve hours after eccentric contractions, twitch force and the 20:50 Hz ratio were decreased for RED but not for NORM. Immediate involuntary with prolonged voluntary force loss suggests that reduced glycogen is associated with increased susceptibility to mild muscle-damaging eccentric exercise with contributions of peripheral and central mechanisms to be different during recovery.

  15. Neuromuscular fatigue is not different between constant and variable frequency stimulation.

    Directory of Open Access Journals (Sweden)

    Maria Papaiordanidou

    Full Text Available This study compared fatigue development of the triceps surae induced by two electrical stimulation protocols composed of constant and variable frequency trains (CFTs, VFTs, 450 trains, 30 Hz, 167 ms ON, 500 ms OFF and 146 ms ON, 500 ms OFF respectively. For the VFTs protocol a doublet (100 Hz was used at the beginning of each train. The intensity used evoked 30% of a maximal voluntary contraction (MVC and was defined using CFTs. Neuromuscular tests were performed before and after each protocol. Changes in excitation-contraction coupling were assessed by analysing the M-wave [at rest (Mmax and during MVC (Msup] and associated peak twitch (Pt. H-reflex [at rest (Hmax and during MVC (Hsup] and the motor evoked potential (MEP during MVC were studied to assess spinal and corticospinal excitability of the soleus muscle. MVC decrease was similar between the protocols (-8%, P<0.05. Mmax, Msup and Pt decreased after both protocols (P<0.01. Hmax/Mmax was decreased (P<0.05, whereas Hsup/Msup and MEP/Msup remained unchanged after both protocols. The results indicate that CFTs and VFTs gave rise to equivalent neuromuscular fatigue. This fatigue resulted from alterations taking place at the muscular level. The finding that cortical and spinal excitability remained unchanged during MVC indicates that spinal and/or supraspinal mechanisms were activated to compensate for the loss of spinal excitability at rest.

  16. Histochemical and immunohistological approach to comparative neuromuscular diseases.

    Directory of Open Access Journals (Sweden)

    Serenella Papparella

    2009-12-01

    Full Text Available The broad category of neuromuscular diseases covers conditions that involve the weakness or wasting of the body muscles. These problems may occur in the spinal cord, the peripheral nerves or the muscle fibers. Some may be hereditary, while others are acquired. Commonly recognized conditions fall into the categories of myopathies, which are diseases of the muscle like muscular dystrophy, disorders of the junction where the nerve impulses are transmitted to the muscle like myasthenia gravis, and neuropathies, which are diseases of the peripheral nervous system. The diagnosis of most neuromuscular diseases rest on careful clinical evaluation of the patient, electromyography, the muscle biopsy, and in some instances, molecular genetic studies. Muscle biopsy, associated to histochemical and immunohistological techniques, plays a key role in diagnosis of many neuromuscular disorders. A number of morphological abnormalities of muscle can be recognized on histological stains such as haematoxylin and eosin and Engel trichrome. Histochemical techniques are essential for the study of muscle biopsies for four main reasons. First, they demonstrate the non-uniform nature of the muscle highlighting the different biochemical properties of specific fibre type and their selective involvement in certain disease processes. Second, they may show an absences of a particular enzyme. Third, an excess of a particular substrate can be demonstrated. Fourth, they may show structural changes in the muscle which would not be apparent with routine histological stains, such as the enzyme-deficient cores in central core disease "mouth-eaten" fibers, and abnormalities in the distribution of mitochondria. In some neuromuscular disorders there could be only non-specific myopathological features. However, a number of proteins, including sarcolemmal, sarcomeric, and nuclear proteins as well as enzymes with defects responsible for neuromuscular disorders, have been identified during

  17. Efectos del vendaje neuromuscular sobre la flexibilidad del raquis lumbar

    Directory of Open Access Journals (Sweden)

    A.M. Labrador-Cerrato

    2015-03-01

    Full Text Available Introducción: El vendaje neuromuscular es una técnica que produce una estimulación muy selectiva sobre la piel a través de la aplicación de unas vendas elásticas especiales con el fin de lograr cambios propioceptivos, aumento o inhibición del tono muscular y mitigación de algias, entre otros. Objetivos: Comprobar si la aplicación del vendaje neuromuscular permite aumentar la flexión del raquis lumbar comparándola con otras técnicas de vendaje placebo (esparadrapo rígido convencional; Omniplaste®-E; observar la concordancia entre la prueba sit-and-reach y el test de Schober en la valoración de la ganancia de flexión lumbar. Material y métodos: Estudio piloto experimental a triple ciego. Se distribuyeron aleatoriamente 45 sujetos sanos de 20-55 años en tres grupos: 1 esparadrapo convencional; 2 Omniplaste®-E; 3 vendaje neuromuscular. En todos los participantes se evaluó la flexión del raquis lumbar mediante la prueba sit-and-reach y el test de Schober antes y después de la intervención siguiendo el mismo protocolo. Resultados: Considerado un intervalo de confianza del 95% y grado de significación estadística p<0,05 en todos los casos, se obtuvo un incremento estadísticamente significativo de la flexión lumbar en todos los grupos según la prueba sit-and-reach, que fue mayor en el grupo del vendaje neuromuscular (1,5 cm de mediana; p=0,011. Según el test de Schober, solamente el vendaje neuromuscular se mostró eficiente (p<0,001, incrementándose el valor basal en un 6,25% (1 cm de mediana. Conclusiones: La aplicación del vendaje neuromuscular sobre la columna lumbar mejora la flexión lumbar respecto a técnicas placebo a partir de los resultados obtenidos mediante el test de Schober, así como una mayor flexión global del tronco que estas técnicas según la prueba sit-and-reach. El test de Schober parece ser más fiable y preciso que la prueba sit-and-reach para estudios de este tipo.

  18. Independent backup mode transfer and mechanism for digital control computers

    Science.gov (United States)

    Tulpule, Bhalchandra R. (Inventor); Oscarson, Edward M. (Inventor)

    1992-01-01

    An interrupt is provided to a signal processor having a non-maskable interrupt input, in response to the detection of a request for transfer to backup software. The signal processor provides a transfer signal to a transfer mechanism only after completion of the present machine cycle. Transfer to the backup software is initiated by the transfer mechanism only upon reception of the transfer signal.

  19. Mechanical and controller design of a modular mechatronic device - mechacell

    OpenAIRE

    Ristevski, Stefan

    2015-01-01

    Cataloged from PDF version of thesis. Includes bibliographical references (leaves 75-79). Thesis (M.S.): Bilkent University, The Department of Mechanical Engineering, İhsan Doğramacı Bilkent University, 2015. Since ancient times people have been building tools to aid them in their life. Robots evolved from being purely mechanical to mechatronic, from immobile to mobile and became smaller in scale. As the technology in building robots matured researchers, began working to bui...

  20. Genomic and proteomic profiling reveals reduced mitochondrial function and disruption of the neuromuscular junction driving rat sarcopenia.

    Science.gov (United States)

    Ibebunjo, Chikwendu; Chick, Joel M; Kendall, Tracee; Eash, John K; Li, Christine; Zhang, Yunyu; Vickers, Chad; Wu, Zhidan; Clarke, Brian A; Shi, Jun; Cruz, Joseph; Fournier, Brigitte; Brachat, Sophie; Gutzwiller, Sabine; Ma, QiCheng; Markovits, Judit; Broome, Michelle; Steinkrauss, Michelle; Skuba, Elizabeth; Galarneau, Jean-Rene; Gygi, Steven P; Glass, David J

    2013-01-01

    Molecular mechanisms underlying sarcopenia, the age-related loss of skeletal muscle mass and function, remain unclear. To identify molecular changes that correlated best with sarcopenia and might contribute to its pathogenesis, we determined global gene expression profiles in muscles of rats aged 6, 12, 18, 21, 24, and 27 months. These rats exhibit sarcopenia beginning at 21 months. Correlation of the gene expression versus muscle mass or age changes, and functional annotation analysis identified gene signatures of sarcopenia distinct from gene signatures of aging. Specifically, mitochondrial energy metabolism (e.g., tricarboxylic acid cycle and oxidative phosphorylation) pathway genes were the most downregulated and most significantly correlated with sarcopenia. Also, perturbed were genes/pathways associated with neuromuscular junction patency (providing molecular evidence of sarcopenia-related functional denervation and neuromuscular junction remodeling), protein degradation, and inflammation. Proteomic analysis of samples at 6, 18, and 27 months confirmed the depletion of mitochondrial energy metabolism proteins and neuromuscular junction proteins. Together, these findings suggest that therapeutic approaches that simultaneously stimulate mitochondrogenesis and reduce muscle proteolysis and inflammation have potential for treating sarcopenia.

  1. Adaptive Control Methods for Mechanical Manipulators: A Comparative Study

    Science.gov (United States)

    1989-12-01

    control task is to what extent one should take into account real robot dynamics in control synthesis. Current industrial practices, in order to take...in an attempt to be able to take advantage of the full robot dynamics and to overcome the limitations of the actually available practices [16,17...given to the question of how to use the knowledge of the robot dynamics to synthesize such control that would be simple enough to implement in practice

  2. Neuromuscular Control of Rapid Linear Accelerations in Fish

    Science.gov (United States)

    2016-06-22

    examine the relative balance between planned feedforward motor commands and reflexive feedback modulation. Our proposal was to train fish to...of the sensor, b is the bias of the gyro, which drifts 3 An gu la r v el oc ity (d eg s -1 ) -100 -50 0 50 100 Gyro To ta l a cc el . ( g) -1.5 -1...realistic lev- els of noise. We simulated a tail beat that includes yawing and rolling at the tail beat frequency, which leads to a pulse of forward accel

  3. Adaptive Clutch Engaging Process Control for Automatic Mechanical Transmission

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-ou; CHEN Hui-yan; DING Hua-rong; HE Zhong-bo

    2005-01-01

    Based on detail analysis of clutch engaging process control targets and adaptive demands, a control strategy which is based on speed signal, different from that of based on main clutch displacement signal, is put forward. It considers both jerk and slipping work which are the most commonly used quality evaluating indexes of vehicle starting phase. The adaptive control system and its reference model are discussed profoundly.Taking the adaptability to different starting gears and different road conditions as examples, some proving field test records are shown to illustrate the main clutch adaptive control strategy at starting phase. Proving field test gives acceptable results.

  4. Prognostics Enhanced Reconfigurable Control of Electro-Mechanical Actuators

    Data.gov (United States)

    National Aeronautics and Space Administration — Actuator systems are employed widely in aerospace, transportation and industrial processes to provide power to critical loads, such as aircraft control surfaces....

  5. The role of patient advocacy organisations in neuromuscular disease R&D - The case of the Dutch neuromuscular disease association VSN

    NARCIS (Netherlands)

    Boon, W.P.C.; Broekgaarden, R.

    2010-01-01

    This article investigates to what extent patient advocacy organisations play a role in influencing R&D and policymaking for rare neuromuscular diseases. The Dutch neuromuscular disease organisation VSN is studied in depth. A brief history of the VSN is sketched along with the international embedding

  6. Influência do lítio no bloqueio neuromuscular produzido pelo atracúrio e pelo cisatracúrio: estudo em preparações nervo frênico-diafragma de rato Influencia del litio en el bloqueo neuromuscular producido por el atracurio y por el cisatracurio: estudio en preparo nervio frénico-diafragma del ratón Influence of lithium on the neuromuscular blockade produced by atracurium and cisatracurium: study on rat phrenic nerve-diaphragm preparations

    Directory of Open Access Journals (Sweden)

    Samanta Cristina Antoniassi Fernandes

    2007-06-01

    alteraciones en los potenciales de placa terminal en miniatura mostraron una acción presináptica.BACKGROUND AND OBJECTIVES: Lithium is widely used for the treatment of bipolar disorders and can interact with neuromuscular blockers. There is a controversy about the mechanisms by which it affects neuromuscular transmission and its interaction with neuromuscular blockers. The objective of this study was to evaluate, on the rat diaphragm, the effects of lithium on the muscular response and indirect stimulation, and the possible interaction with neuromuscular blockers. METHODS: Rats weighing between 250 and 300 g were sacrificed under urethane anesthesia. The phrenic nerve-diaphragm preparation was assembled according to the Bulbring technique. The diaphragm was kept under tension, connected to an isometric transducer, and submitted to indirect stimulation with a frequency of 0.1 Hz. The contractions of the diaphragm were registered on a physiograph. The analysis of the amplitude of the muscular responses evaluated: the effects of the isolated drugs: lithium (1.5 mg.mL-1; atracurium (20 µg.mL-1, and cisatracurium (3 µg.mL-1; the lithium-neuromuscular blockers association; and the effects of lithium on the neuromuscular blockade produced by atracurium (35 µg.mL-1 and cisatracurium (5 µg.mL-1. The effects were evaluated before and 45 minutes after the addition of the drugs. The effects of lithium on membrane potentials (MP and miniature end-plate potentials (MEPP were also evaluated. RESULTS: Lithium by itself did not change the amplitude of the muscular responses, but it decreased significantly the neuromuscular blockade produced by atracurium and cisatracurium. It did not change MP and caused an initial increase in MEPP. CONCLUSIONS: Lithium by itself did not compromise neuromuscular transmission and increased the resistance to the effects of atracurium and cisatracurium. It did not show any action on the muscle fiber, and the changes in miniature end-plate potentials

  7. Control Mechanism Strategies for Spin-Stabilized Projectiles

    Science.gov (United States)

    2008-09-01

    from more traditional smart weapons, thus warranting basic research into guidance and control strategies. Conventional methods include canards, fins...moment arms. AACC XNXN  . (1) 14 CG CP Nose Base Figure 13. Relationship between maneuver footprint and control axial location. XC CG MC

  8. An Intelligent Call Admission Control Decision Mechanism for Wireless Networks

    CERN Document Server

    S., Ramesh Babu H; S, Satyanarayana P

    2010-01-01

    The Call admission control (CAC) is one of the Radio Resource Management (RRM) techniques plays instrumental role in ensuring the desired Quality of Service (QoS) to the users working on different applications which have diversified nature of QoS requirements. This paper proposes a fuzzy neural approach for call admission control in a multi class traffic based Next Generation Wireless Networks (NGWN). The proposed Fuzzy Neural Call Admission Control (FNCAC) scheme is an integrated CAC module that combines the linguistic control capabilities of the fuzzy logic controller and the learning capabilities of the neural networks .The model is based on Recurrent Radial Basis Function Networks (RRBFN) which have better learning and adaptability that can be used to develop the intelligent system to handle the incoming traffic in the heterogeneous network environment. The proposed FNCAC can achieve reduced call blocking probability keeping the resource utilisation at an optimal level. In the proposed algorithm we have c...

  9. Impaired axonal Na+ current by hindlimb unloading: implication for disuse neuromuscular atrophy

    Directory of Open Access Journals (Sweden)

    Chimeglkham eBanzrai

    2016-02-01

    Full Text Available This study aimed to characterize the excitability changes in peripheral motor axons caused by hindlimb unloading, which is a model of disuse neuromuscular atrophy. Hindlimb unloading was performed in normal 6-week-old male mice by fixing the proximal tail by a clip connected to the top of the animal’s cage for 3 weeks. Axonal excitability studies were performed by stimulating the sciatic nerve at the ankle and recording the compound muscle action potential from the foot. The amplitudes of the motor responses of the unloading group were 51% of the control amplitudes (2.2 ± 1.3 mV [HLU] vs. 4.3 ± 1.2 mV [Control], P = 0.03. Multiple axonal excitability analysis showed that the unloading group had a smaller strength-duration time constant (SDTC and late subexcitability (recovery cycle than the controls (0.075 ± 0.01 [HLU] vs. 0.12 ± 0.01 [Control], P < 0.01; 5.4 ± 1.0 [HLU] vs. 10.0 ± 1.3 % [Control], P = 0.01, respectively. Three weeks after releasing from HLU, the SDTC became comparable to the control range. Using a modeling study, the observed differences in the waveforms could be explained by reduced persistent Na+ currents along with parameters related to current leakage. Quantification of RNA of a SCA1A gene coding a voltage-gated Na+ channel tended to be decreased in the sciatic nerve in HLU. The present study suggested that axonal ion currents are altered in vivo by hindlimb unloading. It is still undetermined whether the dysfunctional axonal ion currents have any pathogenicity on neuromuscular atrophy or are the results of neural plasticity by atrophy.

  10. Physical damping in IDA-PBC controlled underactuated mechanical systems : Special issue on Hamiltonian and Lagrangian Methods for Nonlinear Control

    NARCIS (Netherlands)

    Gómez-Estern, F.; Schaft, A.J. van der

    2004-01-01

    Energy shaping and passivity-based control designs have proven to be effective in solving control problems for underactuated mechanical systems. In recent works, Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) has been successfully applied to open loop conservative models, i

  11. Anormalidades neuromuscular no desuso, senilidade e caquexia Neuromuscular abnormalities in disuse, cachexia and ageing

    Directory of Open Access Journals (Sweden)

    João Aris Kouyoumdjian

    1993-09-01

    Full Text Available É feita revisão de literatura sobre as principais alterações do sistema neuromuscular no desuso, senilidade e caquexia no ser humano e em modelos animais. A diminuição do diâmetro das fibras musculares após período de inatividade/imobilidade (desuso deve-se à perda de miofibrilas periféricas não ocorrendo formação de core-targetóides ou diminuição da atividade da miofosforilase, próprias da desnervação; mantêm-se a liberação espontânea de acetilcolina e fatores tróficos na junção mio-neural; em geral são afetadas preferencialmente fibras II, que podem assumir forma angular. Existe um processo contínuo intrínseco de envelhecimento de nervos e músculos, com desnervação e reinervação lenta e progressiva; o número de unidades motoras se reduz após 60 anos, sem ocorrência de atividade elétrica desnervatória; a quantidade de acetilcolina liberada nos neurônios terminais e a capacidade máxima de utilização de oxigênio estão diminuídas; a redução da capacidade oxidativa mitocondrial pode explicar o aumento de fibras I, mantendo-se o equilíbrio energético. Após poucas semanas de caquexia as fibras musculares podem ter o diâmetro reduzido em 30%, essa redução ocorre em ordem decrescente nos músculos dos membros inferiores, superiores e tronco; existe atrofia II preferencial com fibras angulares ocasionais, redução de RNA/síntese proteica, mantendo-se DNA normal.Cachexia, ageing and disuse and their effects on the human and animals neuromuscular system are reviewed. Disuse induces reduction of muscle fibers (mainly II diameter with peripheral myofibrils lost; there is no core-targetoid or even reduction on myophosphorilase activity, both typical of denervation; the acetylcholine spontaneous release and trophic factors on myoneural junction are maintained; muscle fibers could change to angular shape. Ageing affects nerve and muscle by a continuous and progressive process of denervation and reinner

  12. An overview of neurological and neuromuscular signs in mitochondrial diseases.

    Science.gov (United States)

    Chaussenot, A; Paquis-Flucklinger, V

    2014-05-01

    Mitochondrial disorders have a broad clinical spectrum and are genetically heterogeneous, involving two genomes. These disorders may be develop at any age, with isolated or multiple system involvement, and any pattern of inheritance. Neurological involvement is the most frequent, and concerns muscular, peripheral and central nervous system. Among these diverse signs, some are suggestive of mitochondrial disease, such as progressive external ophthalmoplegia, exercise intolerance, psychomotor regression, stroke-like episodes, refractory epilepsy and Epilepsia Partialis Continua. Others are less specific and mitochondrial hypothesis may be evocated because of either association of different neuromuscular signs or a multisystemic involvement. This review describes the wealth of this neurological and neuromuscular symptomatology through different syndromes reported in the literature, according to preponderant signs and to modes of inheritance, as key elements to guide genetics testing.

  13. Correction: β-Sialon nanowires, nanobelts and hierarchical nanostructures: morphology control, growth mechanism and cathodoluminescence properties

    Science.gov (United States)

    Huang, Juntong; Huang, Zhaohui; Liu, Yangai; Fang, Minghao; Chen, Kai; Huang, Yaoting; Huang, Saifang; Ji, Haipeng; Yang, Jingzhou; Wu, Xiaowen; Zhang, Shaowei

    2016-07-01

    Correction for `β-Sialon nanowires, nanobelts and hierarchical nanostructures: morphology control, growth mechanism and cathodoluminescence properties' by Juntong Huang, et al., Nanoscale, 2014, 6, 424-432.

  14. Ketogenic Diet in Neuromuscular and Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Antonio Paoli

    2014-01-01

    Full Text Available An increasing number of data demonstrate the utility of ketogenic diets in a variety of metabolic diseases as obesity, metabolic syndrome, and diabetes. In regard to neurological disorders, ketogenic diet is recognized as an effective treatment for pharmacoresistant epilepsy but emerging data suggests that ketogenic diet could be also useful in amyotrophic lateral sclerosis, Alzheimer, Parkinson’s disease, and some mitochondriopathies. Although these diseases have different pathogenesis and features, there are some common mechanisms that could explain the effects of ketogenic diets. These mechanisms are to provide an efficient source of energy for the treatment of certain types of neurodegenerative diseases characterized by focal brain hypometabolism; to decrease the oxidative damage associated with various kinds of metabolic stress; to increase the mitochondrial biogenesis pathways; and to take advantage of the capacity of ketones to bypass the defect in complex I activity implicated in some neurological diseases. These mechanisms will be discussed in this review.

  15. Report on Adaptive Force, a specific neuromuscular function

    Directory of Open Access Journals (Sweden)

    Marko Hoff

    2015-08-01

    Full Text Available In real life motions, as well as in sports, the adaptation of the neuromuscular systems to externally applied forces plays an important role. The term Adaptive Force (AF shall characterize the ability of the nerve-muscle-system to adapt to impacting external forces during isometric and eccentric muscle action. The focus in this paper is on the concept of this neuromuscular action, which is not yet described in this way. A measuring system was constructed and evaluated for this specific neuromuscular function, but only the main information of the evaluation of the measuring system and the preliminary reference values are mentioned here, while an article with detailed description will be published separately. This paper concentrates on the three following points: 1 What is the peculiarity of this neuromuscular function, introduced as AF? 2 Is the measuring system able to capture its specific characteristics and which phases of measurement occur? 3 It seems reasonable to discuss if AF can be distinguished and classified among the known force concepts. The article describes the measuring system and how it is able to capture special features of real life motions like submaximal intensities and the subjects’ option to react adequately on external varying forces. Furthermore, within one measurement the system records three different force qualities: the isometric submaximal Adaptive Force (AFiso, the maximal isometric Adaptive Force (AFisomax and the maximal eccentric Adaptive Force (AFeccmax. Each of these phases provide different and unique information on the nerve-muscle-system that are discussed in detail. Important, in terms of the Adaptive Force, seems to be the combination of conditional and coordinative abilities.

  16. Aggravated neuromuscular symptoms of mercury exposure from dental amalgam fillings.

    Science.gov (United States)

    Akbal, Ayla; Yılmaz, Hınç; Tutkun, Engin; Köş, Durdu Mehmet

    2014-01-01

    Dental amalgam fillings are widely used all over the world. However, their mercury content can lead to various side effects and clinical problems. Acute or chronic mercury exposure can cause several side effects on the central nerve system, renal and hepatic functions, immune system, fetal development and it can play a role on exacerbation of neuromuscular diseases. In this case, we will present a patient with vacuolar myopathy whose symptoms were started and aggravated with her dental amalgam fillings.

  17. RESEARCH ON MECHANICAL MEASUREMENT-ORIENTED INTELLIGENT VIRTUAL CONTROLS

    Institute of Scientific and Technical Information of China (English)

    Tang Baoping; Qin Shuren

    2004-01-01

    Intelligent virtual control (IVC) is an intelligent measurement instrument unit with the function of actual measurement instruments, and the unit can be used as basic building block for a variety of more complex virtual measurement instruments on a PC. IVC is a further advancement from virtual instrument (VI), and it fuses the function modules and the controls modules so that the relationship between the functions and controls of an instrument is imbedded in one or more units. The design, implementation and optimization methods of IVCs are introduced. The computer software representation of IVCs is discussed. An example of an actual VI constructed with the building blocks of IVCs is given.

  18. Lyapunov based nonlinear control of electrical and mechanical systems

    Science.gov (United States)

    Behal, Aman

    This Ph.D. dissertation describes the design and implementation of various control strategies centered around the following applications: (i) an improved indirect field oriented controller for the induction motor, (ii) partial state feedback control of an induction motor with saturation effects, (iii) tracking control of an underactuated surface vessel, and (iv) an attitude tracking controller for an underactuated spacecraft. The theory found in each of these sections is demonstrated through simulation or experimental results. An introduction to each of these four primary chapters can be found in chapter one. In the second chapter, the previously published tracking control of [16] 1 is presented in the indirect field oriented control (IFOC) notation to achieve exponential rotor velocity/rotor flux tracking. Specifically, it is illustrated how the proposed IFOC controller can be rewritten in the manner of [16] to allow for a direct Lyapunov stability proof. Experimental results (implemented with the IFOC algorithm) are provided to corroborate the efficacy of the algorithm. In the third chapter, a singularity-free, rotor position tracking controller is presented for the full order, nonlinear dynamic model of the induction motor that includes the effects of magnetic saturation. Specifically, by utilizing the pi-equivalent saturation model, an observer/controller strategy is designed that achieves semi-global exponential rotor position tracking and only requires stator current, rotor velocity, and rotor position measurements. Simulation and experimental results are included to demonstrate the efficacy of the proposed algorithm. In the fourth chapter, a continuous, time-varying tracking controller is designed that globally exponentially forces the position/orientation tracking error of an under-actuated surface vessel to a neighborhood about zero that can be made arbitrarily small (i.e., global uniformly ultimately boundedness (GUUB)). The result is facilitated by

  19. The effect of a Lucia jig for 30 minutes on neuromuscular re-programming, in normal subjects

    Directory of Open Access Journals (Sweden)

    Mariangela Salles Pereira Nassar

    2012-12-01

    Full Text Available The Lucia jig is a technique that promotes neuromuscular reprogramming of the masticatory system and allows the stabilization of the mandible without the interference of dental contacts, maintaining the mandible position in harmonic condition with the musculature in normal subjects or in patients with temporomandibular dysfunction (TMD. This study aimed to electromyographically analyze the activity (RMS of the masseter and temporal muscles in normal subjects (control group during the use of an anterior programming device, the Lucia jig, in place for 0, 5, 10, 20 and 30 minutes to demonstrate its effect on the stomatognathic system. Forty-two healthy dentate individuals (aged 21 to 40 years with normal occlusion and without parafunctional habits or temporomandibular dysfunction (RDC/TMD were evaluated on the basis of the electromyographic activity of the masseter and temporal muscles before placement of a neuromuscular re-programming device, the Lucia jig, on the upper central incisors. There were no statistically significant differences (p < 0.05 in the electromyographic activity of the masticatory muscles in the different time periods. The Lucia jig changed the electromyographic activity by promoting a neuromuscular reprogramming. In most of the time periods, it decreased the activation of the masticatory muscles, showing that this device has wide applicability in dentistry. The use of a Lucia jig over 0, 5, 10, 15, 20 and 30 minutes did not promote any statistically significant increase in muscle activity despite differences in the data, thus showing that this intra-oral device can be used in dentistry.

  20. Neuromuscular responses to simulated brazilian jiu-jitsu fights.

    Science.gov (United States)

    da Silva, Bruno Victor Corrêa; Ide, Bernardo Neme; de Moura Simim, Mário Antônio; Marocolo, Moacir; da Mota, Gustavo Ribeiro

    2014-12-01

    The aim of this study was to investigate the neuromuscular performance responses following successive Brazilian Jiu-Jitsu (BJJ) fights. Twenty-three BJJ athletes (age: 26.3 ± 6.3 years; body mass: 79.4 ± 9.7 kg; body height: 1.80 ± 0.1 m) undertook 3 simulated BJJ fights (10 min duration each separated by 15 min of rest). Neuromuscular performance was measured by the bench press throw (BPT) and vertical counter movement jump (VCMJ) tests, assessed before the 1st fight (Pre) and after the last one (Post). Blood lactate (LA) was measured at Pre, 1 min Post, and 15 min Post fights. Paired t-tests were employed in order to compare the BPT and VCMJ results. One-way ANOVA with Bonferroni post hoc tests were utilized to compare LA responses. The results revealed a significant (p BJJ fights demanded considerable anaerobic contribution of ATP supply, reinforcing the high-intensity intermittent nature of the sport. Nevertheless, no negative impact on acute neuromuscular performance (power) was observed.

  1. Fatty replacement of lower paraspinal muscles: normal and neuromuscular disorders

    Energy Technology Data Exchange (ETDEWEB)

    Hader, H.; Gadoth, N.; Heifetz, H.

    1983-11-01

    The physiologic replacement of the lower paraspinal muscles by fat was evaluated in 157 patients undergoing computed tomography for reasons unrelated to abnormalities of the locomotor system. Five patients with neuromuscular disorders were similarly evaluated. The changes were graded according to severity at three spinal levels: lower thoracic-upper lumbar, midlumbar, and lumbosacral. The results were analyzed in relation to age and gender. It was found that fatty replacement of paraspinal muscles is a normal age-progressive phenomenon most prominent in females. It progresses down the spine, being most advanced in the lumbosacral region. The severest changes in the five patients with neuromuscular disorders (three with poliomyelitis and two with progressive muscular dystrophy) consisted of complete muscle group replacement by fat. In postpoliomyelitis atrophy, the distribution was typically asymmetric and sometimes lacked clinical correlation. In muscular dystrophy, fatty replacement was symmetric, showing relative sparing of the psoas and multifidus muscles. In patients with neuromuscular diseases, computed tomography of muscles may be helpful in planning a better rehabilitation regimen.

  2. Mechanisms Involved in Nematode Control by Endophytic Fungi

    NARCIS (Netherlands)

    Schouten, Sander

    2016-01-01

    Colonization of plants by particular endophytic fungi can provide plants with improved defenses toward nematodes. Evidently, such endophytes can be important in developing more sustainable agricultural practices. The mechanisms playing a role in this quantitative antagonism are poorly understood

  3. CONCEPTUAL APPROACHES TO CREATE CONTROL MECHANISM BY PASSENGER COMMUTATION SERVICES

    Directory of Open Access Journals (Sweden)

    V. O. Zadoya

    2010-11-01

    Full Text Available In the article the basic approaches of improving a management mechanism for passenger suburban railway transportations are considered, and the classification of reformation models for passenger suburban railway transportations depending on scales, degree of independence, department subordination and amount of proprietors of future company is offered.

  4. Mechanisms for quality control of misfolded transmembrane proteins

    OpenAIRE

    Houck, Scott A.; Cyr, Douglas M.

    2011-01-01

    To prevent the accumulation of misfolded and aggregated proteins, the cell has developed a complex network of cellular quality control (QC) systems to recognize misfolded proteins and facilitate their refolding or degradation. The cell faces numerous obstacles when performing quality control on transmembrane proteins. Transmembrane proteins have domains on both sides of a membrane and QC systems in distinct compartments must coordinate to monitor the folding status of the protein. Additionall...

  5. Group Theoretical Approach for Controlled Quantum Mechanical Systems

    Science.gov (United States)

    2007-11-06

    evolution equation with Hamiltonians which may possess discrete , continuous, and mixed spectrum. For such a quantum system, the Hamiltonian operator...study of classical linear and nonlinear systems, which proves to be very useful in understanding the design problems such as disturbance decoupling...developed by Kunita can then be implemented to establish controllability conditions for the original time-dependent Schrodinger control problem. The end

  6. Research in Fluid Mechanics, Control Theory and Such in Yugoslavia

    Science.gov (United States)

    1988-08-17

    microcom- verized coal in a steam reactor . There is presently a joint puter control systems, industrial robot systems, systems German and Yugoslav program on...of computer aided design to the semibatch column con- involves over 30 industrial companies and the two Slovene trol connected with the paper mill...M. Milanovic, "Computer Stefan Institute. Aided Design of Semibatch Distillation Column Control,’ Proceedings of the 2nd European Simulation Congress

  7. Quantum and classical control of single photon states via a mechanical resonator

    Science.gov (United States)

    Basiri-Esfahani, Sahar; Myers, Casey R.; Combes, Joshua; Milburn, G. J.

    2016-06-01

    Optomechanical systems typically use light to control the quantum state of a mechanical resonator. In this paper, we propose a scheme for controlling the quantum state of light using the mechanical degree of freedom as a controlled beam splitter. Preparing the mechanical resonator in non-classical states enables an optomechanical Stern-Gerlach interferometer. When the mechanical resonator has a small coherent amplitude it acts as a quantum control, entangling the optical and mechanical degrees of freedom. As the coherent amplitude of the resonator increases, we recover single photon and two-photon interference via a classically controlled beam splitter. The visibility of the two-photon interference is particularly sensitive to coherent excitations in the mechanical resonator and this could form the basis of an optically transduced weak-force sensor.

  8. Computerized cognitive training and brain derived neurotrophic factor during bed rest: mechanisms to protect individual during acute stress

    Science.gov (United States)

    Passaro, Angelina; Soavi, Cecilia; Sanz, Juana M.; Morieri, Mario L.; Dalla Nora, Edoardo; Kavcic, Voyko; Narici, Marco V.; Reggiani, Carlo; Biolo, Gianni; Zuliani, Giovanni; Lazzer, Stefano; Pišot, Rado

    2017-01-01

    Acute stress, as bed rest, was shown to increase plasma level of the neurotrophin brain-derived neurotrophic factor (BDNF) in older, but not in young adults. This increase might represent a protective mechanism towards acute insults in aging subjects. Since computerized cognitive training (CCT) is known to protect brain, herein we evaluated the effect of CCT during bed rest on BDNF, muscle mass, neuromuscular function and metabolic parameters. The subjects that underwent CCT did not show an increase of BDNF after bed rest, and showed an anti-insular modification pattern in metabolism. Neuromuscular function parameters, already shown to beneficiate from CCT, negatively correlated with BDNF in research participants undergoing CCT, while positively correlated in the control group. In conclusion, BDNF increase can be interpreted as a standardized protective mechanism taking place whenever an insult occurs; it gives low, but consistent preservation of neuromuscular function. CCT, acting as an external protective mechanism, seems to modify this standardized response, avoiding BDNF increase or possibly modifying its time course. Our results suggest the possibility of differential neuroprotective mechanisms among ill and healthy individuals, and the importance of timing in determining the effects of protective mechanisms. PMID:28161695

  9. The impact of a firm's internal control mechanisms on the choice of innovation mode

    Institute of Scientific and Technical Information of China (English)

    LIU Xinmin; LI Yuan; SU Zhongfeng; FENG Jinlu

    2007-01-01

    A finn's internal control mechanisms may have a significant influence on the choice of innovation mode. Therefore, based on the research on the internal control mechanisms of companies, we developed a model to explore the relationship between a finn's internal control mechanisms and the choice of innovation mode. Using a sample of 585 Chinese finns, this study tests the proposed model. Results show that strategic control has a positive relationship with radical innovation, but a negative relationship with incremental innovation, while financial control has a negative relationship with radical innovation, but a positive relationship with incremental innovation.

  10. Mechanical AGN Feedback: Controlling the Thermodynamical Evolution of Elliptical Galaxies

    CERN Document Server

    Gaspari, M; Temi, P

    2012-01-01

    A fundamental gap in the current understanding of galaxies concerns the thermodynamical evolution of the ordinary, baryonic matter. On one side, radiative emission drastically decreases the thermal energy content of the interstellar plasma (ISM), inducing a slow cooling flow toward the centre. On the other side, the active galactic nucleus (AGN) struggles to prevent the runaway cooling catastrophe, injecting huge amount of energy in the ISM. The present study intends to deeply investigate the role of mechanical AGN feedback in (isolated or massive) elliptical galaxies, extending and completing the mass range of tested cosmic environments. Our previously successful feedback models, in galaxy clusters and groups, demonstrated that AGN outflows, self-regulated by cold gas accretion, are able to properly quench the cooling flow, without destroying the cool core. Via 3D hydrodynamic simulations (FLASH 3.3), including also stellar evolution, we show that massive mechanical AGN outflows can indeed solve the cooling ...

  11. Mechanical control over valley magnetotransport in strained graphene

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ning, E-mail: maning@stu.xjtu.edu.cn [Department of Physics, MOE Key Laboratory of Advanced Transducers and Intelligent Control System, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Shengli, E-mail: zhangsl@mail.xjtu.edu.cn [Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Daqing, E-mail: liudq@cczu.edu.cn [School of Mathematics and Physics, Changzhou University, Changzhou 213164 (China)

    2016-05-06

    Recent experiments report that the graphene exhibits Landau levels (LLs) that form in the presence of a uniform strain pseudomagnetic field with magnitudes up to hundreds of tesla. We further reveal that the strain removes the valley degeneracy in LLs, and leads to a significant valley polarization with inversion symmetry broken. This accordingly gives rise to the well separated valley Hall plateaus and Shubnikov–de Haas oscillations. These effects are absent in strainless graphene, and can be used to generate and detect valley polarization by mechanical means, forming the basis for the new paradigm “valleytronics” applications. - Highlights: • We explore the mechanical strain effects on the valley magnetotransport in graphene. • We analytically derive the dc collisional and Hall conductivities under strain. • The strain removes the valley degeneracy in Landau levels. • The strain causes a significant valley polarization with inversion symmetry broken. • The strain leads to the well separated valley Hall and Shubnikov–de Haas effects.

  12. Fatigue in neuromuscular disorders: focus on Guillain–Barré syndrome and Pompe disease

    OpenAIRE

    2009-01-01

    textabstractFatigue accounts for an important part of the burden experienced by patients with neuromuscular disorders. Substantial high prevalence rates of fatigue are reported in a wide range of neuromuscular disorders, such as Guillain-Barré syndrome and Pompe disease. Fatigue can be subdivided into experienced fatigue and physiological fatigue. Physiological fatigue in turn can be of central or peripheral origin. Peripheral fatigue is an important contributor to fatigue in neuromuscular di...

  13. Mechanically Controlled Electron Transfer in a Single-Polypeptide Transistor

    Science.gov (United States)

    Sheu, Sheh-Yi; Yang, Dah-Yen

    2017-01-01

    Proteins are of interest in nano-bio electronic devices due to their versatile structures, exquisite functionality and specificity. However, quantum transport measurements produce conflicting results due to technical limitations whereby it is difficult to precisely determine molecular orientation, the nature of the moieties, the presence of the surroundings and the temperature; in such circumstances a better understanding of the protein electron transfer (ET) pathway and the mechanism remains a considerable challenge. Here, we report an approach to mechanically drive polypeptide flip-flop motion to achieve a logic gate with ON and OFF states during protein ET. We have calculated the transmission spectra of the peptide-based molecular junctions and observed the hallmarks of electrical current and conductance. The results indicate that peptide ET follows an NC asymmetric process and depends on the amino acid chirality and α-helical handedness. Electron transmission decreases as the number of water molecules increases, and the ET efficiency and its pathway depend on the type of water-bridged H-bonds. Our results provide a rational mechanism for peptide ET and new perspectives on polypeptides as potential candidates in logic nano devices.

  14. Mechanical characterization of calcium pectinate hydrogel for controlled drug delivery

    Directory of Open Access Journals (Sweden)

    Chung Jin Thau

    2003-01-01

    Full Text Available Calcium pectinate beads, a paniculate hydrogel system, is an attractive drug carrier for oral delivery. In this study, a poorly water-soluble model drug indomethacin was incorporated into calcium pectinate beads made of different pectin concentrations, which were produced by an extrusion method. The effect of pectin concentration on bead size, circularity, swelling behavior, and mechanical properties, as well as in vitro drug release profile was investigated. The mechanical properties of calcium pectinate beads were determined by a micromanipulation technique. The drug release profile was measured using a standard British Pharmacopoeia method. It was found that the beads made of higher pectin concentration in general had a less permeable matrix structure and greater mechanical rigidity, although they swelled more after hydration. However, such an effect was not significant when the pectin concentration was increased to above 8%. Micromanipulation measurements showed that there was significant relaxation of the force being imposed on single hydrated beads when they were held, but this phenomenon did not occur on dry beads, which means that the force relaxation was dominated by liquid loss from the beads. The rate of the force relaxation was determined, and has been related to the release rate of the model drug entrapped in the calcium pectinate beads.

  15. Probable Mechanisms of Needling Therapies for Myofascial Pain Control

    Directory of Open Access Journals (Sweden)

    Li-Wei Chou

    2012-01-01

    Full Text Available Myofascial pain syndrome (MPS has been defined as a regional pain syndrome characterized by muscle pain caused by myofascial trigger points (MTrPs clinically. MTrP is defined as the hyperirritable spot in a palpable taut band of skeletal muscle fibers. Appropriate treatment to MTrPs can effectively relieve the clinical pain of MPS. Needling therapies, such as MTrP injection, dry needling, or acupuncture (AcP can effectively eliminate pain immediately. AcP is probably the first reported technique in treating MPS patients with dry needling based on the Traditional Chinese Medicine (TCM theory. The possible mechanism of AcP analgesia were studied and published in recent decades. The analgesic effect of AcP is hypothesized to be related to immune, hormonal, and nervous systems. Compared to slow-acting hormonal system, nervous system acts in a faster manner. Given these complexities, AcP analgesia cannot be explained by any single mechanism. There are several principles for selection of acupoints based on the TCM principles: “Ah-Shi” point, proximal or remote acupoints on the meridian, and extra-meridian acupoints. Correlations between acupoints and MTrPs are discussed. Some clinical and animal studies of remote AcP for MTrPs and the possible mechanisms of remote effectiveness are reviewed and discussed.

  16. Sand control mechanism analysis of metallic wool screen

    Energy Technology Data Exchange (ETDEWEB)

    Yongquan, H.; Jinzhou, Z.; Zhinjun, W.; Zhaofeng, L. [Southwest Petroleum Institute, China, (China); Lei, Y. [Liaohe petroleum Administration, China, (China)

    1997-08-01

    A filter prepacked with metallic wool was developed and claimed to have been effectively used on thermal and unconsolidated sand oil wells. Structural features of the filter screen and the factors having a bearing on its sand control function, such as particle characteristics, fluid properties, environmental conditions, and the filtering characteristics of metallic wool, were discussed. Some experimental results have been provided to illustrate desirable characteristics and advantages. According to this evidence, sanding velocity is highest at the beginning, stabilizing gradually. Production pressure drop must be appropriately adjusted to achieve best results with well sanding control. 9 refs., 1 tab., 5 figs.

  17. Decoherence control: A feedback mechanism based on hamiltonian tracking

    CERN Document Server

    Katz, G; Kosloff, R; Katz, Gil; Ratner, Mark; Kosloff, Ronnie

    2006-01-01

    Enviroment - caused dissipation disrupts the hamiltonian evolution of all quantum systems not fully isolated from any bath. We propose and examine a feedback-control scheme to eliminate such dissipation, by tracking the free hamiltonian evolution. We determine a driving-field that maximizes the projection of the actual molecular system onto the freely propagated one. The evolution of a model two level system in a dephasing bath is followed, and the driving field that overcomes the decoherence is calculated. An implementation of the scheme in the laboratory using feedback control is suggested.

  18. Lie Algebroids in Classical Mechanics and Optimal Control

    Directory of Open Access Journals (Sweden)

    Eduardo Martínez

    2007-03-01

    Full Text Available We review some recent results on the theory of Lagrangian systems on Lie algebroids. In particular we consider the symplectic and variational formalism and we study reduction. Finally we also consider optimal control systems on Lie algebroids and we show how to reduce Pontryagin maximum principle.

  19. Metabolic and structural changes in lower-limb skeletal muscle following neuromuscular electrical stimulation: a systematic review.

    Directory of Open Access Journals (Sweden)

    Maurice J H Sillen

    Full Text Available BACKGROUND: Transcutaneous neuromuscular electrical stimulation (NMES can be applied as a complementary intervention to regular exercise training programs. A distinction can be made between high-frequency (HF NMES and low-frequency (LF NMES. In order to increase understanding of the mechanisms of functional improvements following NMES, the purpose of this study was to systematically review changes in enzyme activity, muscle fiber type composition and muscle fiber size in human lower-limb skeletal muscles following only NMES. METHODS: Trials were collected up to march 2012 and were identified by searching the Medline/PubMed, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL and The Physical Therapy Evidence Database (PEDro databases and reference lists. 18 trials were reviewed in detail: 8 trials studied changes in enzyme activities, 7 trials studied changes in muscle fiber type composition and 14 trials studied changes in muscle fiber size following NMES. RESULTS: The methodological quality generally was poor, and the heterogeneity in study design, study population, NMES features and outcome parameters prohibited the use of meta-analysis. Most of the LF-NMES studies reported significant increases in oxidative enzyme activity, while the results concerning changes in muscle fiber composition and muscle size were conflicting. HF-NMES significantly increased muscle size in 50% of the studies. CONCLUSION: NMES seems to be a training modality resulting in changes in oxidative enzyme activity, skeletal muscle fiber type and skeletal muscle fiber size. However, considering the small sample sizes, the variance in study populations, the non-randomized controlled study designs, the variance in primary outcomes, and the large heterogeneity in NMES protocols, it is difficult to draw definitive conclusions about the effects of stimulation frequencies on muscular changes.

  20. Snail levels control the migration mechanism of mesenchymal tumor cells.

    Science.gov (United States)

    Belgiovine, Cristina; Chiesa, Giulio; Chiodi, Ilaria; Frapolli, Roberta; Bonezzi, Katiuscia; Taraboletti, Giulia; D'Incalci, Maurizio; Mondello, Chiara

    2016-07-01

    Cancer cells use two major types of movement: Mesenchymal, which is typical of cells of mesenchymal origin and depends on matrix metalloproteinase (MMP) activity, and amoeboid, which is characteristic of cells with a rounded shape and relies on the activity of Rho-associated kinase (ROCK). The present authors previously demonstrated that, during neoplastic transformation, telomerase-immortalized human fibroblasts (cen3tel cells) acquired a ROCK-dependent/MMP independent mechanism of invasion, mediated by the downregulation of the ROCK cellular inhibitor Round (Rnd)3/RhoE. In the present study, cen3tel transformation was also demonstrated to be paralleled by downregulation of Snail, a major determinant of the mesenchymal movement. To test whether Snail levels could determine the type of movement adopted by mesenchymal tumor cells, Snail was ectopically expressed in tumorigenic cells. It was observed that ectopic Snail did not increase the levels of typical mesenchymal markers, but induced cells to adopt an MMP-dependent mechanism of invasion. In cells expressing ectopic Snail, invasion became sensitive to the MMP inhibitor Ro 28-2653 and insensitive to the ROCK inhibitor Y27632, suggesting that, once induced by Snail, the mesenchymal movement prevails over the amoeboid one. Snail-expressing cells had a more aggressive behavior in vivo, and exhibited increased tumor growth rate and metastatic ability. These results confirm the high plasticity of cancer cells, which can adopt different types of movement in response to changes in the expression of specific genes. Furthermore, the present findings indicate that Rnd3 and Snail are possible regulators of the type of invasion mechanism adopted by mesenchymal tumor cells.