WorldWideScience
1

Altered neuromuscular control mechanisms of the trapezius muscle in fibromyalgia  

OpenAIRE

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, betwe...

Karlsson Stefan J; Grönlund Christer; Gerdle Björn; Holtermann Andreas; Roeleveld Karin

2010-01-01

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Altered neuromuscular control mechanisms of the trapezius muscle in fibromyalgia  

Directory of Open Access Journals (Sweden)

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.

Karlsson Stefan J

2010-03-01

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NEUROMUSCULAR CONTROL IN LUMBAR DISORDERS  

OpenAIRE

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 percep...

Ville Leinonen

2004-01-01

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NEUROMUSCULAR CONTROL IN LUMBAR DISORDERS  

Directory of Open Access Journals (Sweden)

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 to sense a rotational movement in the lumbar area and thus had clearly impaired lumbar movement perception (p = 0.006. Abnormal MEPs had only inconsistent and SEPs showed no associations with impaired movement perception and postural stability in LSS. Abnormal needle EMG findings and flexion-extension activation of paraspinal muscles were frequently observed in LSS patients. Lumbar paraspinal muscle endurance was better than in previously evaluated healthy subjects and chronic LBP patients (p < 0.001. The results demonstrated clearly impaired lumbar sensory and motor function in sciatica and LSS patients. The pure reflex activation of paraspinal muscles was not affected in sciatica but a difference was found in the premotoneuronal response control. The impaired proprioceptive functions and premotoneuronal response control seem to recover at least partially but the maintenance of postural stability is a complex activity which does not seem to recover automatically in operated sciatica patients at least in three months follow-up. Paraspinal muscle denervation and dysfunction were clearly detectable in LSS but lumbar paraspinal muscle endurance was unexpectedly good.

Ville Leinonen

2004-03-01

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Assessing neuromuscular mechanisms in human-exoskeleton interaction.  

Science.gov (United States)

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. PMID:25570182

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

2014-08-01

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Invasive home mechanical ventilation, mainly focused on neuromuscular disorders  

OpenAIRE

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 th...

Bo?rger, Sandra; Becker, Kurt; Karg, Ortrud; Geiseler, Jens; Zimolong, Andreas

2010-01-01

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Invasive home mechanical ventilation, mainly focused on neuromuscular disorders  

Directory of Open Access Journals (Sweden)

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. Mobile home ventilators are available for the implementation of the ventilation. Their technical performance however, differs regrettably. Studies comparing the economic aspects of ventilation in a hospital to outpatient ventilation, describe home ventilation as a more cost-effective alternative to in-patient care in an intensive care unit, however, more expensive in comparison to a noninvasive (via mask ventilation. Higher expenses arise due to the necessary equipment and the high expenditure of time for the partial 24-hour care of the affected patients through highly qualified personnel. However, none of the studies applies to the German provisionary conditions. The calculated costs strongly depend on national medical fees and wages of caregivers, which barely allows a transmission of the results. The results of quality-of-life studies are mostly qualitative. The patient’s quality of life using mechanical ventilation is predominantly considered well. Caregivers of ventilated patients report positive as well as negative ratings. Regarding the ethical questions, it was researched which aspects of ventilation implementation will have to be considered. From a legal point of view the financing of home ventilation, especially invasive mechanical ventilation, requiring specialised technical nursing is regulated in the code of social law (Sozialgesetzbuch V. The absorption of costs is distributed to different insurance carriers, who often, due to cost pressures within the health care system, insurance carriers, who consider others and not themselves as responsible. Therefore in practice, the necessity to enforce a claim of cost absorption often arises in order to exercise the basic right of free choice of location. Conclusion: Positive effects of the invasive mechanical ventilation (overall survival and symptomatic are highly probable based on the analysed literature, although with a low level of evidence. An establishment of a home ventilation registry and health care research to ascertain valid data to improve outpatient structures is necessary. Gathering specific G

Börger, Sandra

2010-01-01

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Neuromuscular Exercise Post Partial Medial Meniscectomy : Randomized Controlled Trial  

DEFF Research Database (Denmark)

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 outcomes included additional measures of knee joint load distribution, patient-reported outcomes, maximal knee and hipmuscle strength, and physical function measures. RESULTS: 60 out of 62 randomized participants (97%) completed the trial. There were no significant between-group differences in the change in the peak knee adduction moment during normal pace walking (mean difference (95% CI), 0.22 (-0.11 to 0.55) Nm/BW×HT %, p=0.19), or during one-leg sit-to-stand (-0.01 (-0.33 to 0.31) Nm/BW×HT %, p = 0.95). There were also no significant between-group differences for any of the secondary outcomes. CONCLUSIONS: In patients 3-12 months following a medial arthroscopic partial meniscectomy, a neuromuscular exercise program did not alter the peak knee adduction moment, a key predictor of osteoarthritis structural disease progression. Australia and New Zealand Clinical Trials Registry (#ACTRN12612000542897).

Hall, Michelle; Hinman, Rana S

2014-01-01

9

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

OpenAIRE

El control neuromuscular ha sido descrito como un importante factor para el éxito en el rendimiento deportivo. Del mismo modo, también se ha identificado como clave en la prevención y readaptación de las lesiones deportivas. El principal objetivo de esta tesis doctoral ha sido evaluar la eficacia de diferentes tipos de entrenamiento neuromuscular en deportistas.Se ha utilizado una muestra de 81 deportistas sanos entre los diferentes estudios que se presentan. Las diferentes evaluaciones r...

Fort Vanmeerhaeghe, Azahara

2010-01-01

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Neuromuscular control of aerodynamic forces and moments in the blowfly, Calliphora vicina.  

Science.gov (United States)

Flies are among the most agile of flying insects, a capacity that ultimately results from their nervous system's control over steering muscles and aerodynamic forces during flight. In order to investigate the relationships among neuromuscular control, musculo-skeletal mechanics and flight forces, we captured high-speed, three-dimensional wing kinematics of the blowfly, Calliphora vicina, while simultaneously recording electromyogram signals from prominent steering muscles during visually induced turns. We used the quantified kinematics to calculate the translational and rotational components of aerodynamic forces and moments using a theoretical quasi-steady model of force generation, confirmed using a dynamically scaled mechanical model of a Calliphora wing. We identified three independently controlled features of the wingbeat trajectory--downstroke deviation, dorsal amplitude and mode. Modulation of each of these kinematic features corresponded to both activity in a distinct steering muscle group and a distinct manipulation of the aerodynamic force vector. This functional specificity resulted from the independent control of downstroke and upstroke forces rather than the independent control of separate aerodynamic mechanisms. The predicted contributions of each kinematic feature to body lift, thrust, roll, yaw and pitch are discussed. PMID:15472014

Balint, Claire N; Dickinson, Michael H

2004-10-01

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

DEFF Research Database (Denmark)

OBJECTIVE: The project aimed to implement neuromuscular training during a full soccer and handball league season and to experimentally analyze the neuromuscular adaptation mechanisms elicited by this training during a standardized sidecutting maneuver known to be associated with non-contact anterior cruciate ligament (ACL) injury. DESIGN: The players were tested before and after 1 season without implementation of the prophylactic training and subsequently before and after a full season with the implementation of prophylactic training. PARTICIPANTS: A total of 12 female elite soccer players and 8 female elite team handball players aged 26 +/- 3 years at the start of the study. INTERVENTION: The subjects participated in a specific neuromuscular training program previously shown to reduce non-contact ACL injury. METHODS: Neuromuscular activity at the knee joint, joint angles at the hip 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 activity and landing activity electromyography (EMG) of the semitendinosus (P < 0.05), while quadriceps EMG activity remained unchanged. CONCLUSIONS: Neuromuscular training increased EMG activity for the medial hamstring muscles, thereby decreasing the risk of dynamic valgus. This observed neuromuscular adaptation during sidecutting could potentially reduce the risk for non-contact ACL injury.

Zebis, Mette K; Bencke, Jesper

2008-01-01

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Optimality in neuromuscular systems.  

Science.gov (United States)

We provide an overview of optimal control methods to nonlinear neuromuscular systems and discuss their limitations. Moreover we extend current optimal control methods to their application to neuromuscular models with realistically numerous musculotendons; as most prior work is limited to torque-driven systems. Recent work on computational motor control has explored the used of control theory and estimation as a conceptual tool to understand the underlying computational principles of neuromuscular systems. After all, successful biological systems regularly meet conditions for stability, robustness and performance for multiple classes of complex tasks. Among a variety of proposed control theory frameworks to explain this, stochastic optimal control has become a dominant framework to the point of being a standard computational technique to reproduce kinematic trajectories of reaching movements (see [12]) In particular, we demonstrate the application of optimal control to a neuromuscular model of the index finger with all seven musculotendons producing a tapping task. Our simulations include 1) a muscle model that includes force- length and force-velocity characteristics; 2) an anatomically plausible biomechanical model of the index finger that includes a tendinous network for the extensor mechanism and 3) a contact model that is based on a nonlinear spring-damper attached at the end effector of the index finger. We demonstrate that it is feasible to apply optimal control to systems with realistically large state vectors and conclude that, while optimal control is an adequate formalism to create computational models of neuro-musculoskeletal systems, there remain important challenges and limitations that need to be considered and overcome such as contact transitions, curse of dimensionality, and constraints on states and controls. PMID:21095783

Theodorou, Evangelos; Valero-Cuevas, Francisco J

2010-01-01

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Co-simulation of neuromuscular dynamics and knee mechanics during human walking.  

Science.gov (United States)

This study introduces a framework for co-simulating neuromuscular dynamics and knee joint mechanics during gait. A knee model was developed that included 17 ligament bundles and a representation of the distributed contact between a femoral component and tibial insert surface. The knee was incorporated into a forward dynamics musculoskeletal model of the lower extremity. A computed muscle control algorithm was then used to modulate the muscle excitations to drive the model to closely track measured hip, knee, and ankle angle trajectories of a subject walking overground with an instrumented knee replacement. The resulting simulations predicted the muscle forces, ligament forces, secondary knee kinematics, and tibiofemoral contact loads. Model-predicted tibiofemoral contact forces were of comparable magnitudes to experimental measurements, with peak medial (1.95 body weight (BW)) and total (2.76 BW) contact forces within 4-17% of measured values. Average root-mean-square errors over a gait cycle were 0.26, 0.42, and 0.51 BW for the medial, lateral, and total contact forces, respectively. The model was subsequently used to predict variations in joint contact pressure that could arise by altering the frontal plane joint alignment. Small variations (±2 deg) in the alignment of the femoral component and tibial insert did not substantially affect the location of contact pressure, but did alter the medio-lateral distribution of load and internal tibia rotation in swing. Thus, the computational framework can be used to virtually assess the coupled influence of both physiological and design factors on in vivo joint mechanics and performance. PMID:24390129

Thelen, Darryl G; Won Choi, Kwang; Schmitz, Anne M

2014-02-01

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Neuromuscular scoliosis.  

Science.gov (United States)

The purpose of this focused review is to provide an overview of neuromuscular scoliosis from the perspective of the rehabilitation physician. Scoliosis is a common consequence of neuromuscular diseases, including central nervous system disorders such as cerebral palsy and spinal cord injury; motor neuron disorders, for example, spinal muscular atrophy; muscle fiber disorders, for example, Duchenne muscular dystrophy; multifactorial disorders, for example, spina bifida; and many other neuropathic and myopathic conditions. Unlike adolescent idiopathic scoliosis, which is the most common form of spinal deformity, neuromuscular scoliosis is more severe and more progressive, and is associated with more morbidity. Factors that contribute to this spinal deformity include asymmetric paraplegia, imbalance of mechanical forces, intraspinal and congenital anomalies of the spine, altered sensory feedback, and abnormal posture via central pathways. Spinal deformity combined with limitations due to an underlying neuromuscular condition lead to significant physiologic impairments that affect limb movement, cardiopulmonary function, gait, standing, sitting, balance, trunk stability, bimanual activities, activities of daily living, and pain, as well as concerns with self-image and social interactions. Evaluation and management of this population requires understanding of disease progression, pulmonary status, functional limitations, indications for conservative and surgical interventions, and social considerations. PMID:24247014

Allam, Anand M; Schwabe, Aloysia L

2013-11-01

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Aging and limb alter the neuromuscular control of goal-directed movements.  

Science.gov (United States)

The purpose of this study was to determine whether the neuromuscular control of goal-directed movements is different for young and older adults with the upper and lower limbs. Twenty young (25.1 ± 3.9 years) and twenty older adults (71.5 ± 4.8 years) attempted to accurately match the displacement of their limb to a spatiotemporal target during ankle dorsiflexion or elbow flexion movements. We quantified neuromuscular control by examining the movement endpoint accuracy and variability, and the antagonistic muscle activity using surface electromyography (EMG). Our results indicate that older adults exhibit impaired endpoint accuracy with both limbs due to greater time variability. In addition, older adults exhibit greater EMG burst and lower EMG burst variability as well as lower coactivation of the antagonistic muscles. The impaired accuracy of older adults during upper limb movements was related to lower coactivation of the antagonistic muscles, whereas their impaired accuracy during lower limb movements was related to the amplified EMG bursts. The upper limb exhibited greater movement control than the lower limb, and different neuromuscular parameters were related to the accuracy and consistency for each limb. Greater endpoint error during upper limb movements was related to lower coactivation of the antagonistic muscles, whereas greater endpoint error during lower limb movements was related to the amplified EMG bursts. These findings indicate that the age-associated impairments in movement control are associated with altered activation of the involved antagonistic muscles. In addition, independent of age, the neuromuscular control of goal-directed movements is different for the upper and lower limbs. PMID:24557320

Kwon, MinHyuk; Chen, Yen-Ting; Fox, Emily J; Christou, Evangelos A

2014-06-01

16

Phasic respiratory modulation of pharyngeal collapsibility via neuromuscular mechanisms in rats.  

Science.gov (United States)

Obstructive sleep apnea patients experience recurrent upper airway (UA) collapse due to decreases in the UA dilator muscle activity during sleep. In contrast, activation of UA dilators reduces pharyngeal critical pressure (Pcrit, an index of pharyngeal collapsibility), suggesting an inverse relationship between pharyngeal collapsibility and dilator activity. Since most UA muscles display phasic respiratory activity, we hypothesized that pharyngeal collapsibility is modulated by respiratory drive via neuromuscular mechanisms. Adult male Sprague-Dawley rats were anesthetized, vagotomized, and ventilated (normocapnia). In one group, integrated genioglossal activity, Pcrit, and maximal airflow (V(max)) were measured at three expiration and five inspiration time points within the breathing cycle. Pcrit was closely and inversely related to phasic genioglossal activity, with the value measured at peak inspiration being the lowest. In other groups, the variables were measured during expiration and peak inspiration, before and after each of five manipulations. Pcrit was 26% more negative (-15.0 ± 1.0 cmH(2)O, -18.9 ± 1.2 cmH(2)O; n = 23), V(max) was 7% larger (31.0 ± 1.0 ml/s, 33.2 ± 1.1 ml/s), nasal resistance was 12% bigger [0.49 ± 0.05 cmH(2)O/(ml/s), 0.59 ± 0.05 cmH(2)O/(ml/s)], and latency to induced UA closure was 14% longer (55 ± 4 ms, 63 ± 5 ms) during peak inspiration vs. expiration (all P < 0.005). The expiration-inspiration difference in Pcrit was abolished with neuromuscular blockade, hypocapnic apnea, or death but was not reduced by the superior laryngeal nerve transection or altered by tracheal displacement. Collectively, these results suggest that pharyngeal collapsibility is moment-by-moment modulated by respiratory drive and this phasic modulation requires neuromuscular mechanisms, but not the UA negative pressure reflex or tracheal displacement by phasic lung inflation. PMID:22052868

Cao, Ying; McGuire, Michelle; Liu, Chun; Malhotra, Atul; Ling, Liming

2012-03-01

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Unsteady locomotion: integrating muscle function with whole body dynamics and neuromuscular control  

OpenAIRE

By integrating studies of muscle function with analysis of whole body and limb dynamics, broader appreciation of neuromuscular function can be achieved. Ultimately, such studies need to address non-steady locomotor behaviors relevant to animals in their natural environments. When animals move slowly they likely rely on voluntary coordination of movement involving higher brain centers. However, when moving fast, their movements depend more strongly on responses controlled at more local levels....

Biewener, Andrew A.; Daley, Monica A.

2007-01-01

18

Generation of neuromuscular specificity in Drosophila: novel mechanisms revealed by new technologies  

Directory of Open Access Journals (Sweden)

Full Text Available The Drosophila larval neuromuscular system is one of the best-characterized model systems for axon targeting. In each abdominal hemisegment, only 36 identified motor neurons form synaptic connections with just 30 target muscles in a highly specific and stereotypic manner. Studies in the 1990s identified several cell-surface and secreted proteins that are expressed in specific muscles and contribute to target specificity. Emerging evidence suggests that target selection is determined not only by attraction to the target cells but also by exclusion from non-target cells. Proteins with leucine-rich repeats (LRR proteins appear to be a major molecular family of proteins responsible for the targeting. While the demonstrated roles of the target-derived cues point to active recognition by presynaptic motor neurons, postsynaptic muscles also reach out and recognize specific motor neurons by sending out cellular protrusions called myopodia. Simultaneous live imaging of myopodia and growth cones has revealed that local and mutual recognition at the tip of myopodia is critical for selective synapse formation. A large number of candidate target cues have been identified on a single muscle, suggesting that target specificity is determined by the partially redundant and combinatorial function of multiple cues. Analyses of the seemingly simple neuromuscular system in Drosophila have revealed an unexpected complexity in the mechanisms of axon targeting.

AkinaoNose

2012-05-01

19

Effects of neuromuscular lags on controlling contact transitions  

OpenAIRE

We present a numerical exploration of contact transitions with the fingertip. When picking up objects our fingertips must make contact at specific locations, and—upon contact—maintain posture while producing well-directed force vectors. However, the joint torques for moving the fingertip towards a surface (?m) are different from those for producing static force vectors (?f). We previously described the neural control of such abrupt transitions in humans, and found that unavoidable error...

Venkadesan, Madhusudhan; Valero-cuevas, Francisco J.

2009-01-01

20

Early neuromuscular customized training after surgery for lumbar disc herniation: a prospective controlled study  

OpenAIRE

A prospective and controlled study of training after surgery for lumbar disc herniation (LDH). The objective was to determine the effect of early neuromuscular customized training after LDH surgery. No consensus exists on the type and timing of physical rehabilitation after LDH surgery. Patients aged 15–50 years, disc prolapse at L4–L5 or L5–S1. Before surgery, at 6 weeks, 4, and 12 months postoperatively, the following evaluations were performed: low back pain and leg pain estimated on...

Millisdotter, Monica; Stro?mqvist, Bjo?rn

2006-01-01

21

Neuromuscular Scoliosis  

Science.gov (United States)

... Post-Surgical Deformity Diagnosis Imaging Studies Nonoperative Management Surgical Treatment Adult Spinal Deformity Causes Symptoms Diagnosis Radiographs Treatment Options Neuromuscular About Neuromuscular Scoliosis Indications for Surgery Spinal Stabilization Spondylolysis Adolescent Back Pain ...

22

Postoperative effects of neuromuscular exercise prior to hip or knee arthroplasty : a randomised controlled trial  

DEFF Research Database (Denmark)

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 on the activities of daily living (ADL) subscale in the Hip disability and Osteoarthritis Outcome Score (HOOS) and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaires for patients with hip and knee OA, respectively. Primary endpoint was 3 months after surgery. RESULTS: 165 patients randomised to the two groups were on average 67±8 years, 84 (51%) had hip OA and 92 (56%) were women. 153 patients (93%) underwent planned surgery and were evaluated postoperatively. There was no statistically significant difference in effects between hip or knee patients (p=0.7370). Three months postoperatively, no difference was found between groups for ADL (4.4, 95% CI -0.8 to 9.5) or pain (4.5, 95% CI -0.8 to 9.9). However, there was a statistically significant difference indicating an effect of exercise over the entire period (baseline to 3-months postoperatively) (p=0.0029). CONCLUSIONS: Eight weeks of supervised 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 of postoperative recovery. TRIAL REGISTRATION: ClinicalTrials NCT01003756.

Villadsen, Allan; Overgaard, SØren

2014-01-01

23

Related neuropeptides use different balances of unitary mechanisms to modulate the cardiac neuromuscular system in the American lobster, Homarus americanus.  

Science.gov (United States)

To produce flexible outputs, neural networks controlling rhythmic motor behaviors can be modulated at multiple levels, including the pattern generator itself, sensory feedback, and the response of the muscle to a given pattern of motor output. We examined the role of two related neuropeptides, GYSDRNYLRFamide (GYS) and SGRNFLRFamide (SGRN), in modulating the neurogenic lobster heartbeat, which is controlled by the cardiac ganglion (CG). When perfused though an isolated whole heart at low concentrations, both peptides elicited increases in contraction amplitude and frequency. At higher concentrations, both peptides continued to elicit increases in contraction amplitude, but GYS caused a decrease in contraction frequency, while SGRN did not alter frequency. To determine the sites at which these peptides induce their effects, we examined the effects of the peptides on the periphery and on the isolated CG. When we removed the CG and stimulated the motor nerve with constant bursts of stimuli, both GYS and SGRN increased contraction amplitude, indicating that each peptide modulates the muscle or the neuromuscular junction. When applied to the isolated CG, neither peptide altered burst frequency at low peptide concentrations; at higher concentrations, SGRN decreased burst frequency, whereas GYS continued to have no effect on frequency. Together, these data suggest that the two peptides elicit some of their effects using different mechanisms; in particular, given the known feedback pathways within this system, the importance of the negative (nitric oxide) relative to the positive (stretch) feedback pathways may differ in the presence of the two peptides. PMID:25392168

Dickinson, Patsy S; Calkins, Andrew; Stevens, Jake S

2015-02-01

24

Early neuromuscular customized training after surgery for lumbar disc herniation: a prospective controlled study.  

Science.gov (United States)

A prospective and controlled study of training after surgery for lumbar disc herniation (LDH). The objective was to determine the effect of early neuromuscular customized training after LDH surgery. No consensus exists on the type and timing of physical rehabilitation after LDH surgery. Patients aged 15-50 years, disc prolapse at L4-L5 or L5-S1. Before surgery, at 6 weeks, 4, and 12 months postoperatively, the following evaluations were performed: low back pain and leg pain estimated on a visual analog scale, disability according to the Roland-Morris questionnaire (RMQ) and disability rating index (DRI). Clinical examination, including the SLR test, was performed using a single blind method. Consumption of analgesics was registered. Twenty-five patients started neuromuscular customized training 2 weeks after surgery (early training group = ETG). Thirty-one patients formed a control group (CG) and started traditional training after 6 weeks. There was no significant difference in pain and disability between the two training groups before surgery. Median preoperative leg pain was 63 mm in ETG and 70 mm in the CG. Preoperative median disability according to RMQ was 14 in the ETG and 14.5 in the CG. Disability according to DRI (33/56 patients) was 5.3 in the ETG vs. 4.6 in the CG. At 6 weeks, 4 months, and 12 months, pain was significantly reduced in both groups, to the same extent. Disability scores were lower in the ETG at all follow-ups, and after 12 months, the difference was significant (RMQ P=.034, DRI P=.015). The results of the present study show early neuromuscular customized training to have a superior effect on disability, with a significant difference compared to traditional training at a follow-up 12 months after surgery. No adverse effects of the early training were seen. A prospective, randomized study with a larger patient sample is warranted to ultimately demonstrate that early training as described is beneficial for patients undergoing LDH surgery. PMID:16421747

Millisdotter, Monica; Strömqvist, Björn

2007-01-01

25

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

Science.gov (United States)

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.

DeWoody, Yssa

1996-01-01

26

Center of mass acceleration feedback control for standing by functional neuromuscular stimulation: A simulation study  

Directory of Open Access Journals (Sweden)

Full Text Available The potential efficacy of total body center of mass (COM acceleration for feedback control of standing balance by functional neuromuscular stimulation (FNS following spinal cord injury (SCI was investigated. COM acceleration may be a viable alternative to conventional joint kinematics because of its rapid responsiveness, focal representation of COM dynamics, and ease of measurement. A computational procedure was developed using an anatomically realistic, three-dimensional, bipedal biomechanical model to determine optimal patterns of muscle excitations to produce targeted effects upon COM acceleration from erect stance. The procedure was verified with electromyographic data collected from standing nondisabled subjects undergoing systematic perturbations. Using 16 muscle groups targeted by existing implantable neuroprostheses, we generated data to train an artificial neural network (ANN-based controller in simulation. During forward simulations, proportional feedback of COM acceleration drove the ANN to produce muscle excitation patterns countering the effects of applied perturbations. Feedback gains were optimized to minimize upper-limb (UL loading required to stabilize against disturbances. Compared with the clinical case of maximum constant excitation, the controller reduced UL loading by 43% in resisting external perturbations and by 51% during simulated one-arm reaching. Future work includes performance assessment against expected measurement errors and development of user-specific control systems.

Raviraj Nataraj

2012-04-01

27

Proactive and reactive neuromuscular control in subjects with chronic ankle instability: Evidence from a pilot study on landing.  

Science.gov (United States)

To understand why subjects with chronic ankle instability (CAI) have frequent sprains, one must study the preparation/reactions of these subjects to situations related to ankle inversion in real life. In the present pilot study, we examined whether subjects with CAI altered their neuromuscular control and reflex responses during and after ankle perturbations in landing. EMG signals were collected from the tibialis anterior (TA), peroneus longus (PL), medial gastrocnemius (MG), and gluteus medius (GLM) of both legs in 9 subjects with CAI and 9 subjects with intact ankles (control). A trapdoor was used to produce an ankle inversion of 25° with the left leg (control) or the affected leg (CAI) in 0%, 50% or 100% of the landing trials. As compared to controls, subjects with CAI had increased proactive activity in the contralateral side prior to touchdown during landing trials with 50% (PL) and 100% (PL and MG) chance of inversion (all, pproactive control on the contralateral side could be part of a strategy to smooth the impact of landing on the affected side in subjects with CAI. Following touchdown, the CAI group showed decreased ipsilateral short latency reflex (SLR) responses in all test conditions both in distal (PL and MG) and in proximal muscles (GLM) on the affected side (all, p<0.05). Finally, subjects with CAI adjusted their reflex gain differently as compared to controls when exposed to a possible inversion. Overall, individuals with CAI displayed different neuromuscular strategies from controls while landing. PMID:25439444

Levin, Oron; Vanwanseele, Benedicte; Thijsen, Jo R J; Helsen, Werner F; Staes, Filip F; Duysens, Jacques

2015-01-01

28

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A estimulação elétrica neuromuscular (EENM) é um importante recurso utilizado em medicina esportiva para acelerar processos de recuperação. O objetivo deste estudo foi analisar os efeitos da EENM durante a imobilização do músculo gastrocnêmio, em posições de alongamento (LP) e encurtamento (SP). Par [...] a tanto, 60 ratas fêmeas jovens Wistar foram distribuídas em seis grupos e acompanhadas durante sete dias: controle (C), eletroestimuladas (EE), imobilizadas em encurtamento (ISP), imobilizadas em alongamento (ILP), imobilizadas em encurtamento e eletroestimuladas (ISP + EE) e imobilizadas em alongamento e eletroestimuladas (ILP + EE). Para a imobilização, o membro posterior direito foi envolvido por uma malha tubular e ataduras de algodão juntamente à atadura gessada. A EENM foi utilizada com freqüência de 50Hz, 10 minutos por dia, totalizando 20 contrações em cada sessão. Após sete dias os animais foram submetidos a eutanásia e os músculos gastrocnêmios retirados para a realização do ensaio mecânico de tração em uma máquina universal de ensaios (EMIC®). A partir dos gráficos carga versus alongamento, foram calculadas as seguintes propriedades mecânicas: alongamento no limite de proporcionalidade (ALP), carga no limite de proporcionalidade (CLP) e rigidez. As imobilizações SP e LP promoveram reduções significativas (p Abstract in spanish La estimulación eléctrica neuromuscular (EENM) es un importante recurso utilizado en medicina deportiva para acelerar procesos de recuperación. El objetivo de este estudio ha sido analizar los efectos de la EENM durante la inmovilización del músculo gastrocnemio, en posiciones de alongamiento (LP) y [...] contracción (SP). Para tal fin, 60 ratones hembras jóvenes Wistar fueron distribuidas en seis grupos y monitoreadas durante 7 días: control (C), electro estimuladas (EE), inmovilizadas en contracción (ISP), inmovilizadas en alongamiento (ILP), inmovilizadas en contracción y electro estimuladas (ISP + EE) e 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 Abstract in english 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 youn [...] g 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

João Paulo Chieregato, Matheus; Liana Barbaresco, Gomide; Juliana Goulart Prata de, Oliveira; José Batista, Volpon; Antônio Carlos, Shimano.

2007-02-01

29

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

OpenAIRE

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...

Kazon Soráia; Grecco Luanda A C; Pasini Hugo; Corrêa João C F; Christovão Thaluanna C L; de Carvalho Paulo de TarsoCamillo; Giannasi Lilian Chrystiane; Lucareli Paulo R G; de Oliveira Luis Vicente Franco; Salgado Afonso Shiguemi Inoue; Sampaio Luciana M M; Oliveira Claudia S

2012-01-01

30

[Fatigue in neuromuscular disease].  

Science.gov (United States)

Chronic fatigue is a symptom of diseases such as cancer, multiple sclerosis, Parkinson's and cerebrovascular disease. Fatigue can also be present in people with no demonstrable somatic disease. If certain criteria are met, chronic-fatigue syndrome may be diagnosed in these cases. Fatigue is a multi-dimensional concept with physiological and psychological dimensions. The 'Short Fatigue Questionnaire' consisting of 4 questions is a tool to measure fatigue with a high degree of reliability and validity. Within the group of neuromuscular disorders, fatigue has been reported by patients with post-polio syndrome, myasthenia gravis, and Guillain-Barré syndrome. The percentage of neuromuscular patients suffering from severe fatigue (64%) is comparable with that of patients with multiple sclerosis, a disease in which fatigue is an acknowledged symptom. Now that reliable psychological and clinical neurophysiological techniques are available, a multidisciplinary approach to fatigue in patients with well-defined neuromuscular disorders may contribute towards the elucidation of the pathophysiological mechanisms of chronic fatigue, with the ultimate goal being to develop methods of treatment for fatigue in neuromuscular patients. PMID:15283024

Van Engelen, B G M; Kalkman, J S; Schillings, M L; Van Der Werf, S P; Bleijenberg, G; Zwarts, M J

2004-07-01

31

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)

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 effect of the combined use of braces and neuromuscular training, against the use of either braces or neuromuscular training as separate secondary preventive measures. This study expects to identify the most effective and cost-efficient secondary preventive measure for ankle sprains. The study results could lead to changes in the clinical guidelines on the prevention of ankle sprains, and they will become available in 2012. Trial registration Netherlands Trial Register (NTR: NTR2157

Verhagen Evert ALM

2011-09-01

32

Neuromuscular control adaptations in elite athletes: the case of top level karateka.  

Science.gov (United States)

This paper aimed at investigating the neuromuscular response of knee flexor and extensor muscles in elite karateka and karate amateurs (Amateurs) during isokinetic knee flexion/extensions and during the execution of a front kick (FK). Surface electromyograms (sEMG) were recorded from the right vastus lateralis (VL) and biceps femoris (BF) muscles with a four-array electrode during maximal isometric knee flexion and extension (maximal voluntary contraction), during isokinetic contractions (30 degrees , 90 degrees , 180 degrees , 270 degrees , 340 degrees , 400 degrees /s), and during the FK. The level of VL and BF agonist (ago) and antagonist (ant) activation during the isokinetic and FK protocols was quantified through normalized sEMG root mean square value (%RMS(ago/ant-ISOK/FK)). VL and BF average muscle fiber conduction velocity (CV) was computed for isokinetic and FK. Isokinetic flexion and extension torques and knee angular velocity during FK were also assessed. Analysis of variance was used to test the effect of group, angular velocity, and task on the assessed variables (P < 0.05). Elite karateka showed higher isokinetic knee flexion torque when compared with Amateurs. For all angular velocities, VL and BF %RMS(ant-isokinetic) were lower in elite karateka, while their BF-CV(isokinetic) BF-CV(front kick) and BF %RMS(ant-front kick) values were higher. For VL and BF, %RMS(ago-front kick) was lower than %RMS(ago-isokinetic) in both groups. Elite karateka demonstrated a typical neuromuscular activation strategy that seems task and skill level dependent. Knee flexion torque and CV results suggest the presence of an improved ability of elite karateka to recruit fast MUs as a part of training induced neuromuscular adaptation. PMID:20039054

Sbriccoli, Paola; Camomilla, Valentina; Di Mario, Alberto; Quinzi, Federico; Figura, Francesco; Felici, Francesco

2010-04-01

33

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)

Full Text Available JUSTIFICATIVA E OBJETIVOS: A potencialização da procainamida sobre o bloqueio neuromuscular produzido pela d-tubocurarina já está comprovada, porém o mecanismo é controverso. O objetivo do estudo foi avaliar a influência da procainamida no bloqueio neuromuscular produzido pelo rocurônio e investigar os mecanismos desta interação. MÉTODO: Foram utilizados 15 ratos (250 a 300 g em preparação descrita por Bülbring. Formaram-se os seguintes grupos (n = 5 cada: procainamida - 20 µg.mL-1 (Grupo I; rocurônio - 4 µg.mL-1 (Grupo II e rocurônio - 4 µg.mL-1 e procainamida - 20 µg.mL-1 (Grupo III. Avaliaram-se: 1 a amplitude das contrações musculares sob estimulação indireta em cada grupo, antes e após a adição dos fármacos; 2 os potenciais de placa terminal em miniatura (PPTM; 3 a eficácia da 4-aminopiridina na reversão do bloqueio neuromuscular. O mecanismo da interação foi estudado em Biventer cervicis (n = 5 e diafragma de rato desnervado (n = 5, observando-se a influência da procainamida na resposta à acetilcolina antes e após a adição da procainamida. RESULTADOS: A procainamida isoladamente não alterou as respostas neuromusculares. O bloqueio produzido com o Grupo III foi de 68,6% ± 7,1%, com diferença significativa (p = 0,0067 em relação ao Grupo II (10,4% ± 4,5%, revertido pela 4-aminopiridina. A procainamida ocasionou aumento na freqüência dos PPTM, seguido de bloqueio revertido pela 4-aminopiridina. Em Biventer cervicis a procainamida aumentou a resposta à ação de contração da acetilcolina, resultado não observado com o diafragma desnervado. CONCLUSÕES: A procainamida potencializou o bloqueio produzido pelo rocurônio. As alterações observadas com PPTM e Biventer cervicis identificaram ação pré-sináptica. O antagonismo da 4-aminopiridina sobre o bloqueio dos PPTM sugeriu dessensibilização dos receptores pela procainamida.JUSTIFICATIVA Y OBJETIVOS: La potenciación de la procainamida sobre el bloqueo neuromuscular producido por la d-tubocurarina ya está comprobada, pero sin embargo el mecanismo es controvertido. El objetivo del estudio fue el de evaluar la influencia de la procainamida en el bloqueo neuromuscular producido por el rocuronio e investigar los mecanismos de esa interacción. MÉTODO: Se utilizaron 15 ratones (250 a 300 g en preparación descrita por Bülbring. Se formaron los siguientes grupos (n = 5 cada: procainamida - 20 µg.mL-1 (Grupo I; rocuronio - 4 µg.mL-1 (Grupo II y rocuronio - 4µg.mL-1 y procainamida - 20µg.mL-1 (Grupo III. Se evaluó: 1 la amplitud de las contracciones musculares bajo la estimulación indirecta en cada grupo, antes y después de la adición de los fármacos; 2 los potenciales de placa terminal en miniatura (PPTM; 3 la eficacia de la 4-aminopiridina en la reversión del bloqueo neuromuscular. El mecanismo de la interacción se estudió en Biventer cervicis (n = 5 y diafragma de ratón desnervado (n = 5, observándose la influencia de la procainamida en la respuesta a la acetilcolina antes y después de la adición de la procainamida. RESULTADOS: De forma aislada, la procainamida no alteró las respuestas neuromusculares. El bloqueo producido con el Grupo III fue de 68,6% ± 7,1%, con una diferencia significativa (p = 0,0067 con relación al Grupo II (10,4% ± 4,5%, revertido por la 4-aminopiridina. La procainamida ocasionó un aumento en la frecuencia de los PPTM, seguido de bloqueo revertido por la 4-aminopiridina. En Biventer cervicis, la procainamida aumentó la respuesta a la acción de contracción de la acetilcolina, resultado no observado con el diafragma desnervado. CONCLUSIONES: La procainamida potenció el bloqueo producido por el rocuronio. Las alteraciones observadas con PPTM y Biventer cervicis identificaron una acción presináptica. El antagonismo de la 4-aminopiridina sobre el bloqueo de los PPTMs sugirió la desensibilización de los receptores por la procainamida.BACKGROUND AND OBJECTIVES: It has already been proved that

Thalita Duque Martins

2007-02-01

34

Differences in neuromuscular control between impact and no impact roundhouse kick in athletes of different skill levels.  

Science.gov (United States)

This study aimed at investigating two aspects of neuromuscular control around the hip and knee joint while executing the roundhouse kick (RK) using two techniques: Impact RK (IRK) at trunk level and No-Impact RK at face level (NIRK). The influence of technical skill level was also investigated by comparing two groups: elite Karateka and Amateurs. Surface electromyographic (sEMG) signals have been recorded from the Vastus Lateralis (VL), Biceps Femoris (BF), Rectus Femoris (RF), Gluteus Maximum (GM) and Gastrocnemious (GA) muscles of the kicking leg in six Karateka and six Amateurs performing the RKs. Hip and knee kinematics were also assessed. EMG data were rectified, filtered and normalized to the maximal value obtained for each muscle over all trials; co-activation (CI) indexes of antagonist vs. overall (agonist and antagonist) activity were computed for hip and knee flexion and extension. Muscle Fiber Conduction Velocity (CV) obtained from VL and BF muscles was assessed as well. The effect of group and kick on angular velocity, CIs, and CVs was tested through a two-way ANOVA (p velocity; higher BF-CV (IRK: 5.1 ± 1.0 vs. 3.5 ± 0.5 m/s; NIRK: 5.7 ± 1.3 vs. 4.1 ± 0.5 m/s), higher CIs for hip movements and knee flexion and lower CI for knee extension. The results obtained suggest the presence of a skill-dependent activation strategy in the execution of the two kicks. CV results are suggestive of an improved ability of elite Karateka to recruit fast MUs as a part of training induced neuromuscular adaptation. PMID:23089236

Quinzi, Federico; Camomilla, Valentina; Felici, Francesco; Di Mario, Alberto; Sbriccoli, Paola

2013-02-01

35

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

Directory of Open Access Journals (Sweden)

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

Bruce-Brand Robert A

2012-07-01

36

Acute fatigue-induced changes in muscle mechanical properties and neuromuscular activity in elite handball players following a handball match  

DEFF Research Database (Denmark)

The purpose of the present study was to determine the acute fatigue development in muscle mechanical properties and neuromuscular activity in response to handball match play. Male elite handball players (n = 10) were tested before and after a simulated handball match for maximal isometric strength [maximal voluntary contraction (MVC)] and rate of force development (RFD) with synchronous electromyography (EMG) recording, while maximal vertical jump parameters were assessed using force plate analysis. Quadriceps and hamstrings MVC and RFD decreased significantly post-match (approximately 10%, P < 0.05 and approximately 16-21%, P < 0.05, respectively). During quadriceps, MVC mean EMG amplitude [mean average voltage (MAV)] decreased for the vastus lateralis (VL) and rectus femoris (RF) (21-42%, P < or = 0.05), while MAV also decreased in the antagonist biceps femoris (BF) muscle (48-55%, P < 0.01). During hamstring MVC, MAV was reduced in BF (31%, P < 0.01). Maximum EMG amplitude during quadriceps MVC was reducedfor the VL (28%, P < 0.01) and the RF (5%, P < 0.05). During hamstring MVC, maximum EMG was reduced for BF (21%, P < 0.01). Post-match maximal jump height was reduced (5.2%, P < 0.01), as was also work (6.8%, P < 0.01), velocity of center of mass (2.4-4.0%, P < 0.01) and RFD (approximately 30%, P < 0.05). In conclusion, maximal (MVC) and rapid muscle force characteristics (RFD, impulse) were acutely affected concurrently with marked reductions in muscle EMG following handball match play, which may potentially lead to impaired functional performance.

Thorlund, J B; Michalsik, L B

2008-01-01

37

Center of mass acceleration feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations  

Directory of Open Access Journals (Sweden)

Full Text Available This study determined the feasibility and performance of center of mass (COM acceleration feedback control of a neuroprosthesis utilizing functional neuromuscular stimulation (FNS to restore standing balance to a single subject paralyzed by a motor and sensory complete, thoracic-level spinal cord injury. An artificial neural network (ANN was created to map gain-modulated changes in total body COM acceleration estimated from body-mounted sensors to optimal changes in stimulation required to maintain standing. Feedback gains were systematically tuned to minimize the upper-limb (UL loads applied by the subject to an instrumented support device during internally generated postural perturbations produced by volitional reaching and object manipulation. Total body COM acceleration was accurately estimated (>90% variance explained from 2 three-dimensional (3-D accelerometers mounted on the pelvis and torso. Compared with constant muscle stimulation employed clinically, COM acceleration feedback control of stimulation improved standing performance by reducing the UL loading required to resist internal postural disturbances by 27%. This case study suggests that COM acceleration feedback could potentially be advantageous in a standing neuroprosthesis since it can be implemented with only a few feedback parameters and requires minimal instrumentation for comprehensive 3-D control of dynamic standing function.

Raviraj Nataraj

2012-08-01

38

Influência da procainamida sobre o bloqueio neuromuscular produzido pelo rocurônio e investigação sobre o mecanismo de ação da procainamida na junção neuromuscular / Influence of procainamide on the neuromuscular blockade caused by rocuronium and investigation on the mechanism of action of procainamide on the neuromuscular junction / 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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: A potencialização da procainamida sobre o bloqueio neuromuscular produzido pela d-tubocurarina já está comprovada, porém o mecanismo é controverso. O objetivo do estudo foi avaliar a influência da procainamida no bloqueio neuromuscular produzido pelo rocurônio e investigar [...] os mecanismos desta interação. MÉTODO: Foram utilizados 15 ratos (250 a 300 g) em preparação descrita por Bülbring. Formaram-se os seguintes grupos (n = 5 cada): procainamida - 20 µg.mL-1 (Grupo I); rocurônio - 4 µg.mL-1 (Grupo II) e rocurônio - 4 µg.mL-1 e procainamida - 20 µg.mL-1 (Grupo III). Avaliaram-se: 1) a amplitude das contrações musculares sob estimulação indireta em cada grupo, antes e após a adição dos fármacos; 2) os potenciais de placa terminal em miniatura (PPTM); 3) a eficácia da 4-aminopiridina na reversão do bloqueio neuromuscular. O mecanismo da interação foi estudado em Biventer cervicis (n = 5) e diafragma de rato desnervado (n = 5), observando-se a influência da procainamida na resposta à acetilcolina antes e após a adição da procainamida. RESULTADOS: A procainamida isoladamente não alterou as respostas neuromusculares. O bloqueio produzido com o Grupo III foi de 68,6% ± 7,1%, com diferença significativa (p = 0,0067) em relação ao Grupo II (10,4% ± 4,5%), revertido pela 4-aminopiridina. A procainamida ocasionou aumento na freqüência dos PPTM, seguido de bloqueio revertido pela 4-aminopiridina. Em Biventer cervicis a procainamida aumentou a resposta à ação de contração da acetilcolina, resultado não observado com o diafragma desnervado. CONCLUSÕES: A procainamida potencializou o bloqueio produzido pelo rocurônio. As alterações observadas com PPTM e Biventer cervicis identificaram ação pré-sináptica. O antagonismo da 4-aminopiridina sobre o bloqueio dos PPTM sugeriu dessensibilização dos receptores pela procainamida. Abstract in spanish JUSTIFICATIVA Y OBJETIVOS: La potenciación de la procainamida sobre el bloqueo neuromuscular producido por la d-tubocurarina ya está comprobada, pero sin embargo el mecanismo es controvertido. El objetivo del estudio fue el de evaluar la influencia de la procainamida en el bloqueo neuromuscular prod [...] ucido por el rocuronio e investigar los mecanismos de esa interacción. MÉTODO: Se utilizaron 15 ratones (250 a 300 g) en preparación descrita por Bülbring. Se formaron los siguientes grupos (n = 5 cada): procainamida - 20 µg.mL-1 (Grupo I); rocuronio - 4 µg.mL-1 (Grupo II) y rocuronio - 4µg.mL-1 y procainamida - 20µg.mL-1 (Grupo III). Se evaluó: 1) la amplitud de las contracciones musculares bajo la estimulación indirecta en cada grupo, antes y después de la adición de los fármacos; 2) los potenciales de placa terminal en miniatura (PPTM); 3) la eficacia de la 4-aminopiridina en la reversión del bloqueo neuromuscular. El mecanismo de la interacción se estudió en Biventer cervicis (n = 5) y diafragma de ratón desnervado (n = 5), observándose la influencia de la procainamida en la respuesta a la acetilcolina antes y después de la adición de la procainamida. RESULTADOS: De forma aislada, la procainamida no alteró las respuestas neuromusculares. El bloqueo producido con el Grupo III fue de 68,6% ± 7,1%, con una diferencia significativa (p = 0,0067) con relación al Grupo II (10,4% ± 4,5%), revertido por la 4-aminopiridina. La procainamida ocasionó un aumento en la frecuencia de los PPTM, seguido de bloqueo revertido por la 4-aminopiridina. En Biventer cervicis, la procainamida aumentó la respuesta a la acción de contracción de la acetilcolina, resultado no observado con el diafragma desnervado. CONCLUSIONES: La procainamida potenció el bloqueo producido por el rocuronio. Las alteraciones observadas con PPTM y Biventer cervicis identificaron una acción presináptica. El antagonismo de la 4-aminopiridina sobre el bloqueo de los PPTMs sugirió la desensibilización de los receptores por la procainamida. A

Thalita Duque, Martins; Yolanda Christina S., Loyola; Angélica de Fátima de Assunção, Braga.

2007-02-01

39

Knee Joint Biomechanics and Neuromuscular Control During Gait Before and After Total Knee Arthroplasty are Sex-specific.  

Science.gov (United States)

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. PMID:25123606

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

2015-01-01

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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)

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-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during various tasks in people with a partial medial meniscectomy. If shown to reduce the knee adduction moment, neuromuscular exercise has the potential to prevent the onset of osteoarthritis or slow its progression in those with early disease. Trial Registration Australian New Zealand Clinical Trials Registry reference: ACTRN12612000542897

Hall Michelle

2012-11-01

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Neuromuscular features in Marfan syndrome.  

Science.gov (United States)

Marfan syndrome is a clinically and allelic heterogeneous, heritable connective tissue disorder with infrequently reported neuromuscular features. This study is the first to delineate these symptoms in a non-selected population. Neuromuscular involvement was evaluated in 10 Marfan patients through a standardized questionnaire, physical examination, nerve conduction study (NCS), needle electromyography (EMG), muscle ultrasound, laboratory investigation, and muscle biopsy. Existing neuroimages were screened for dural ectasia and spinal meningeal cysts. Twenty healthy controls with similar age distribution completed the questionnaire. The results showed that various neuromuscular symptoms occur more frequently in the patients. Four older patients reported muscle weakness, five patients had a mild-to-moderate reduction in vibration sense, and all older patients mentioned mild functional impairments. NCS showed axonal polyneuropathy in four and EMG myopathic and neurogenic changes in all patients. Increased echo intensity and atrophy on muscle ultrasound was found in more than half of the patients. Muscle biopsies obtained in two patients showed myopathic changes in the older, female patient. In conclusion, the majority of Marfan patients exhibited neuromuscular symptoms characterized as myopathy or polyneuropathy or both, and signs of lumbosacral radiculopathy, with symptoms being most pronounced in the older patients. Although meriting corroboration, these findings indicate a need to further the awareness of neuromuscular involvement in this population. PMID:19659760

Voermans, N c; Timmermans, J; van Alfen, N; Pillen, S; op den Akker, J; Lammens, M; Zwarts, M J; van Rooij, I A L M; Hamel, B C; van Engelen, B G

2009-07-01

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Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The purpose of this study was to determine the comparative effectiveness of feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI. Methods In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM acceleration feedback alone, and combined joint kinematics and COM acceleration feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS, and the resulting joint kinematics and COM acceleration data was analyzed. Results Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics feedback and 35% for COM acceleration feedback. Pilot data indicated that COM acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Conclusions Overall, COM acceleration feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small number of inputs required.

Nataraj Raviraj

2012-05-01

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Randomised controlled trial of non-invasive ventilation (NIV) for nocturnal hypoventilation in neuromuscular and chest wall disease patients with daytime normocapnia  

OpenAIRE

Background: Long term non-invasive ventilation (NIV) reduces morbidity and mortality in patients with neuromuscular and chest wall disease with hypercapnic ventilatory failure, but preventive use has not produced benefit in normocapnic patients with Duchenne muscular dystrophy. Individuals with nocturnal hypercapnia but daytime normocapnia were randomised to a control group or nocturnal NIV to examine whether nocturnal hypoventilation is a valid indication for NIV.

Ward, S.; Chatwin, M.; Heather, S.; Simonds, A.

2005-01-01

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

DEFF Research Database (Denmark)

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.

Larsen, C M; SØgaard, Karen

2013-01-01

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Randomized controlled pilot study of neuromuscular electrical stimulation of the quadriceps in patients with non-small cell lung cancer.  

Science.gov (United States)

Patients with lung cancer experience muscle wasting and weakness. Therapeutic exercise may be beneficial but is not always practical. An alternative approach may be neuromuscular electrical stimulation (NMES) of the quadriceps muscles, but this has not been formally examined in patients with cancer. Thus, we have undertaken this pilot study to assess feasibility and inform the design of future studies. Sixteen patients were randomized to receive usual care (control group) or usual care plus NMES for four weeks. NMES consisted of daily stimulation to both thighs for up to 30minutes (frequency 50Hz, "on" cycle 11%-25%). Adherence was assessed by a self-report diary and a semistructured evaluation form. Quadriceps muscle strength, exercise endurance, and free-living physical activity were assessed using a Cybex NORM dynamometer, an endurance shuttle walk test, and an ActivPAL accelerometer (mean daily step count), respectively. Changes in outcome from baseline were compared between groups by mean differences and their 95% confidence intervals using independent t-test (P=0.05). Median (range) adherence to the program was 80% (69%-100%). All patients found the NMES device easy to use. Changes in outcome favored the NMES group, with mean differences of 9.4 Nm (21%) in quadriceps muscle strength, 768 steps (15%) in free-living activity, and 138 m (8%) in exercise endurance, but none of the differences were statistically significant. In conclusion, NMES warrants further study in patients with lung cancer. PMID:19748761

Maddocks, Matthew; Lewis, Mary; Chauhan, Alpna; Manderson, Cathann; Hocknell, Joanna; Wilcock, Andrew

2009-12-01

46

Control rod drive mechanisms  

International Nuclear Information System (INIS)

Purpose: To operate a reactor safety by making it possible to confirm the soundness of the sliding surface of a cam mechanism or the like used in the control rod drive mechanism. Constitution: A temperature control section for heating or cooling either one of the extended tubes provided in the control rod guide tube is provided, and by varying the temperature difference between the extended tubes, thermal stresses corresponding to the wear due to the biting of the sliding surfaces of the cam mechanism and the like and the depositing force thereof are generated, and detected by load detectors provided in the extended tubes. (Aizawa, K.)

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Early Neuromuscular Electrical Stimulation to Improve Quadriceps Muscle Strength After Total Knee Arthroplasty: A Randomized Controlled Trial  

Science.gov (United States)

Background The recovery of quadriceps muscle force and function after total knee arthroplasty (TKA) is suboptimal, which predisposes patients to disability with increasing age. Objective The purpose of this investigation was to evaluate the efficacy of quadriceps muscle neuromuscular electrical stimulation (NMES), initiated 48 hours after TKA, as an adjunct to standard rehabilitation. Design This was a prospective, longitudinal randomized controlled trial. Methods Sixty-six patients, aged 50 to 85 years and planning a primary unilateral TKA, were randomly assigned to receive either standard rehabilitation (control) or standard rehabilitation plus NMES applied to the quadriceps muscle (initiated 48 hours after surgery). The NMES was applied twice per day at the maximum tolerable intensity for 15 contractions. Data for muscle strength, functional performance, and self-report measures were obtained before surgery and 3.5, 6.5, 13, 26, and 52 weeks after TKA. Results At 3.5 weeks after TKA, significant improvements with NMES were found for quadriceps and hamstring muscle strength, functional performance, and knee extension active range of motion. At 52 weeks, the differences between groups were attenuated, but improvements with NMES were still significant for quadriceps and hamstring muscle strength, functional performance, and some self-report measures. Limitations Treatment volume was not matched for both study arms; NMES was added to the standard of care treatment. Furthermore, testers were not blinded during testing, but used standardized scripts to avoid bias. Finally, some patients reached the maximum stimulator output during at least one treatment session and may have tolerated more stimulation. Conclusions The early addition of NMES effectively attenuated loss of quadriceps muscle strength and improved functional performance following TKA. The effects were most pronounced and clinically meaningful within the first month after surgery, but persisted through 1 year after surgery. PMID:22095207

Balter, Jaclyn E.; Wolfe, Pamela; Eckhoff, Donald G.; Kohrt, Wendy M.

2012-01-01

48

Peroxisomal quality control mechanisms.  

Science.gov (United States)

Peroxisomes are ubiquitous organelles that harbor diverse metabolic pathways, which are essential for normal cell performance. Conserved functions of these organelles are hydrogen peroxide metabolism and ?-oxidation. Cells employ multiple quality control mechanisms to ensure proper peroxisome function and to protect peroxisomes from damage. These involve the function of molecular chaperones, a peroxisomal Lon protease and autophagic removal of dysfunctional organelles. In addition, multiple mechanisms exist to combat peroxisomal oxidative stress. Here, we outline recent advances in our understanding of peroxisomal quality control, focussing on yeast and filamentous fungi. PMID:25305535

Kumar, Sanjeev; Kawa?ek, Adam; van der Klei, Ida J

2014-12-01

49

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)

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-reported physical function measured at baseline and immediately following the program. Secondary outcomes include the external knee adduction moment angular impulse, electromyographic muscle activation patterns, knee and hip muscle strength, balance, functional ability, and quality-of-life. Discussion The findings will help determine whether neuromuscular exercise is superior to traditional quadriceps strengthening regarding effects on knee load, pain and physical function in people with medial knee osteoarthritis and varus malalignment. Trial Registration Australian New Zealand Clinical Trials Registry reference: ACTRN12610000660088

Bennell Kim L

2011-12-01

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A technique for sequential segmental neuromuscular stimulation with closed loop feedback control.  

Science.gov (United States)

In dynamic myoplasty, dysfunctional muscle is assisted or replaced with skeletal muscle from a donor site. Electrical stimulation is commonly used to train and animate the skeletal muscle to perform its new task. Due to simultaneous tetanic contractions of the entire myoplasty, muscles are deprived of perfusion and fatigue rapidly, causing long-term problems such as excessive scarring and muscle ischemia. Sequential stimulation contracts part of the muscle while other parts rest, thus significantly improving blood perfusion. However, the muscle still fatigues. In this article, we report a test of the feasibility of using closed-loop control to economize the contractions of the sequentially stimulated myoplasty. A simple stimulation algorithm was developed and tested on a sequentially stimulated neo-sphincter designed from a canine gracilis muscle. Pressure generated in the lumen of the myoplasty neo-sphincter was used as feedback to regulate the stimulation signal via three control parameters, thereby optimizing the performance of the myoplasty. Additionally, we investigated and compared the efficiency of amplitude and frequency modulation techniques. Closed-loop feedback enabled us to maintain target pressures within 10% deviation using amplitude modulation and optimized control parameters (correction frequency = 4 Hz, correction threshold = 4%, and transition time = 0.3 s). The large-scale stimulation/feedback setup was unfit for chronic experimentation, but can be used as a blueprint for a small-scale version to unveil the theoretical benefits of closed-loop control in chronic experimentation. PMID:12028619

Zonnevijlle, Erik D H; Abadia, Gustavo Perez; Somia, Naveen N; Kon, Moshe; Barker, John H; Koenig, Steven; Ewert, D L; Stremel, Richard W

2002-01-01

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Características e impacto de la sedación, la analgesia y el bloqueo neuromuscular en los pacientes críticos que recibieron ventilación mecánica prolongada / Characteristics and impact of sedation, analgesia, and neuromuscular blockage in critical patients undergoing prolonged mechanical ventilation  

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish Objetivo. Describir el uso de sedantes, analgésicos y bloqueantes neuromusculares (BNM) en los pacientes con ventilación mecánica (VM) prolongada y evaluar los factores asociados a su empleo y asociación con la mortalidad a los 28 días. Diseño. Estudio multicéntrico, prospectivo y observacional de c [...] ohorte. Ámbito. Trece unidades de cuidados intensivos (UCI) en Chile. Pacientes. Pacientes con VM superior a 48h. Excluimos los pacientes con enfermedad neurológica, cirrosis hepática, insuficiencia renal crónica, sospecha de adicción a drogas y limitación precoz del esfuerzo terapéutico. Intervención. Ninguna Variables de interés principales. Proporción de uso y dosis de sedantes, analgésicos y BNM. Nivel de sedación observado (SAS [sedation-agitation scale "escala de sedación-agitación"]). Variables asociadas al nivel de la SAS, y el uso de sedantes, analgésicos y BNM. Regresión logística multivariada de variables asociadas a la mortalidad a los 28 días. Resultados. Participaron 155 pacientes (60±18 años, el 57% eran varones, SOFA 7 [6-10], APACHE II 18 [15-22], el 63% con sepsis y el 47% con lesión pulmonar aguda/síndrome de distrés respiratorio agudo. Los fármacos empleados fueron midazolam (85%; 4 mg/h [1,9-6,8]) y fentanilo (81%; 76 µg/h [39-140]). Un 30% de los pacientes usó BNM al menos un día. El 55% de la SAS fue 1-2. Existe una asociación entre el uso de BNM y la mortalidad a los 28 días, pero ésta no fue consistente en todos los modelos de uso de BNM evaluados. Conclusiones. En el grupo estudiado fue frecuente el uso de sedantes y la presencia de sedación profunda, el midazolam y el fentanilo fueron los fármacos más usados. El uso de BNM podría asociarse de forma independiente a una mayor mortalidad. Abstract in english Aim. To describe use of sedatives, analgesics, and neuromuscular blockers (NMB) in patients undergoing long-term mechanical ventilation and to assess factors associated with their use and their association with mortality at 28 days. Design. Prospective observational multicenter cohort study. Setting [...] . Thirteen intensive care units (ICU) in Chile. Patients. Patients undergoing mechanical ventilation for more than 48h. We excluded patients with neurological disorders, cirrhosis of the liver, chronic renal failure, suspected drug addiction, and early no resuscitation orders. Intervention. None. Main measurements. Proportion of use and dosage of sedatives, analgesics, and NMB. Level of sedation observed (SAS). Variables associated with the Sedation Agitation Scale (SAS), use of sedatives, analgesics, and NMB. Multivariate logistic regression of variables associated to mortality at 28 days. Results. A total of 155 patients participated (60±18 years, 57% male, SOFA 7 [6-10], APACHE II 18 [15-22], 63% with sepsis, and 47% with acute lung injury/adult respiratory distress syndrome. The drugs most frequently used were midazolam (85%, 4 [1.9-6.8]mg/hr) and fentanyl (81%, 76 [39-140]µg/hr). NMB were administered at least 1 day in 30% of patients. SAS score was 1 or 2 in 55% of patients. There was an association between NMB use and mortality at 28 days, but it was not consistent in all the models of NMB evaluated. Conclusions. Sedatives were frequently employed and deep sedation was common. Midazolam and fentanyl were the most frequently administered drugs. The use of NMB might be independently associated to greater mortality.

E., Tobar; G., Bugedo; M., Andresen; M., Aguirre; M.T., Lira; J., Godoy; H., González; A., Hernández; V., Tomicic; J., Castro; J., Jara; H., Ugarte.

2009-10-01

52

Characteristics of neuromuscular control of the scapula after stroke: a first exploration.  

Science.gov (United States)

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?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?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

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

2014-01-01

53

Control rod driving mechanisms  

International Nuclear Information System (INIS)

Purpose: To conduct reactor scram by an external signal and, also by a signal for the abnormal temperature from a temperature detector in the nuclear reactor. Constitution: Control rod driving mechanisms magnetically coupling the extension pipe with the elevating mechanism above the reactor core and the holding magnet, and retains a control rod to the lower portion of the extension pipe by way of a latch mechanism. The temperature detector is immersed in reactor coolants. If the temperature of the coolants rises abnormally, bimetal contacts of the temperature detector are opened to interrupt the current supply to the holding electromagnet. Then, the extension pipe released from the magnetic coupling is lowered and the control rod free from latch is rapidly dropped and inserted into the reactor core. Since this procedure is carried out for all of the control rods, the reactor scram can be attained. The feature of this invention resides in that the reactor scram can be attained also by the signal of the reactor core itself even if the signal system for the external signals should be failed. (Horiuchi, T.)

54

Immediate Efficacy of Neuromuscular Exercise in Patients with Severe Osteoarthritis of the Hip or Knee : A Secondary Analysis from a Randomized Controlled Trial  

DEFF Research Database (Denmark)

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. Patients received an educational package (care-as-usual) only, or care-as-usual plus an 8-week neuromuscular exercise intervention (NEMEX-TJR). NEMEX-TJR was supervised by a physiotherapist, twice weekly for 1 h. The primary outcome was Activities of Daily Living (ADL) subscale from the Hip disability 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 muscle power. RESULTS: Included were 165 patients, 56% female, average age 67 years (SD ± 8), and a body mass index of 30 (SD ± 5), who were scheduled for primary hip or knee replacement. The postintervention difference between mean changes in ADL was 7.2 points (95% CI 3.5 to 10.9, p = 0.0002) in favor of NEMEX-TJR compared with control. Second, there were statistically significant differences between groups in favor of NEMEX-TJR on all self-reported outcomes and most functional performance tests (walk, chair stands, and 1-leg knee bends). Stratified analyses according to joint revealed moderate effect size for ADL for hip patients (0.63, 95% CI 0.26 to 1.00). Corresponding effect size for knee patients was small (0.23 95% CI -0.14 to 0.60). CONCLUSION: Feasibility of neuromuscular exercise was confirmed in patients about to have total joint replacement. Self-reported activities of daily living and objective performance were improved and pain reduced immediately following 8 weeks of neuromuscular exercise. While the effects were moderate in hip OA, they were only small in knee OA. ClinicalTrials.gov Identifier: NCT01003756.

Villadsen, Allan; Overgaard, SØren

2014-01-01

55

Control rod driving mechanism  

International Nuclear Information System (INIS)

Object: To form an outer peripheral surface of a control rod driving rod with a spiral cut having a notched hole with which a pawl mechanism engages to thereby reduce pull-out speed of the control rod, thus avoiding rapid change in output. Structure: When an index tube is moved up in order to insert control rods into the reactor, a collet finger is outwardly biased by a diagonally chamfered inclined surface under the spiral notch to disengage the finger from the notched hole. Then, the index tube moves up along the collet finger, and if the collet finger is axially moved up, it is disengaged from the notched hole when the finger is moved down, whereby the index tube will move down at a speed adjusted by adjusting the thread pitch of the spiral cut and spacing of the notched hole. (Kamimura, M.)

56

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)

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.

AlessandraPedrocchi

2014-09-01

57

Unmammed Gun Control Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available From ages it has been a desire of humans to achieve the ultimate in security and make his loved ones and loved things secure. It is this desire that prompted him to make the boundaries and secure them too from all unseen and unknown sources. For this it has been always necessary to maintain a huge sum of people to guard and raise alarms in cases of emergencies. To accomplish this we propose a mechanism which will employ image processing in which a camera (webcam will be continuously observing the ‘area under surveillance’. This data will be then processed by a MatLab code which will be running on a PC and will be able to detect a particular colour (Say Red in front of a white back ground (depicting snow. Depending on this processed data the information about the intruder location will be sent to a micro-controller (89c51 via the Serial/Parallel port of the PC and then a motor controlled gun will be used to point in the direction of the intruder. This mechanism will be online i.e. the gun will continuously be pointing in the direction of the intruder. Further depending on range (distance from the gun (fixed range in this project the gun can be activated and a Laser pointer will be switched ON depict “shooting the target”.

LAXMI NIDHI, PRATYUSHA ROY, SRISHTY NAYAK, RAJINE SWETHA R

2013-05-01

58

Effects of neuromuscular training (NEMEX-TJR) on patient-reported outcomes and physical function in severe primary hip or knee osteoarthritis : a controlled before-and-after study  

DEFF Research Database (Denmark)

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 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.

Ageberg, Eva; Nilsdotter, Anna

2013-01-01

59

Genetics and Neuromuscular Diseases  

Science.gov (United States)

... not passed on to the next generation. Does DNA from the cell’s nucleus affect the mitochondria? Yes. ... SMA). Pictured here with her parents and her twin siblings, Jory and Aaron. 15 Genetics and Neuromuscular ...

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The effect on knee-joint load of instruction in analgesic use compared with neuromuscular exercise in patients with knee osteoarthritis : study protocol for a randomized, single-blind, controlled trial (the EXERPHARMA trial)  

DEFF Research Database (Denmark)

BACKGROUND: Knee osteoarthritis (OA) is a mechanically driven disease, and it is suggested that medial tibiofemoral knee-joint load increases with pharmacologic pain relief, indicating that pharmacologic pain relief may be positively associated with disease progression. Treatment modalities that can both relieve pain and reduce knee-joint load would be preferable. The knee-joint load is influenced by functional alignment of the trunk, pelvis, and lower-limb segments with respect to the knee, as well as the ground-reaction force generated during movement. Neuromuscular exercise can influence knee load and decrease knee pain. It includes exercises to improve balance, muscle activation, functional alignment, and functional knee stability. The primary objective of this randomized controlled trial (RCT) is to investigate the efficacy of a NEuroMuscular EXercise (NEMEX) therapy program, compared with optimized analgesics and antiinflammatory drug use, on the measures of knee-joint load in people with mild to moderate medial tibiofemoral knee osteoarthritis. METHOD/DESIGN: One hundred men and women with mild to moderate medial knee osteoarthritis will be recruited from general medical practices and randomly allocated (1:1) to one of two 8-week treatments, either (a) NEMEX therapy twice a week or (b) information on the recommended use of analgesics and antiinflammatory drugs (acetaminophen and oral NSAIDs) via a pamphlet and video materials. The primary outcome is change in knee load during walking (the Knee Index, a composite score of the first external peak total reaction moment on the knee joint from all three planes based on 3D movement analysis) after 8 weeks of intervention. Secondary outcomes include changes in the external peak knee-adduction moment and impulse and functional performance measures, in addition to changes in self-reported pain, function, health status, and quality of life. DISCUSSION: These findings will help determine whether 8 weeks of neuromuscular exercise is superior to optimized use of analgesics and antiinflammatory drugs regarding knee-joint load, pain and physical function in people with mild to moderate knee osteoarthritis. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01638962 (July 3, 2012).

Clausen, Brian; Holsgaard-Larsen, Anders

2014-01-01

61

Neuromuscular versus quadriceps strengthening exercise in patients with medial knee osteoarthritis and varus malalignment : a randomized controlled trial  

DEFF Research Database (Denmark)

OBJECTIVE: To compare the effects of neuromuscular exercise (NEXA) and quadriceps strengthening (QS) on the knee adduction moment (an indicator of mediolateral distribution of knee load), pain, and physical function in patients with medial knee joint osteoarthritis (OA) and varus malalignment. METHODS: One hundred patients with medial knee pain, mostly moderate-to-severe radiographic medial knee OA, and varus malalignment were randomly allocated to one of two 12-week exercise programs. Each program involved 14 individually supervised exercise sessions with a physiotherapist plus a home exercise component. Primary outcomes were peak external knee adduction moment (3-dimensional gait analysis), pain (visual analog scale), and self-reported physical function (Western Ontario and McMaster Universities Osteoarthritis Index). RESULTS: Eighty-two patients (38 [76%] of 50 in the NEXA group and 44 [88%] of 50 in the QS group) completed the trial. There was no significant between-group difference in the change in thepeak knee adduction moment (mean difference 0.13 Nm/[body weight × height]% [95% confidence interval (95% CI) -0.08, 0.33]), pain (mean difference 2.4 mm [95% CI -6.0, 10.8]), or physical function (mean difference -0.8 units [95% CI -4.0, 2.4]). Neither group showed a change in knee moments following exercise, whereas both groups showed similar significant reductions in pain and improvement in physical function. CONCLUSION: Although comparable improvements in clinical outcomes were observed with both neuromuscular and quadriceps strengthening exercise in patients with moderate varus malalignment and mostly moderate-to-severe medial knee OA, these forms of exercise did not affect the knee adduction moment, a key predictor of structural disease progression.

Bennell, Kim L; Kyriakides, Mary

2014-01-01

62

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

LENUS (Irish Health Repository)

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.

O'Driscoll, Jeremiah

2011-06-09

63

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

Directory of Open Access Journals (Sweden)

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.

O'Driscoll Jeremiah

2011-06-01

64

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

Directory of Open Access Journals (Sweden)

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.

M Hadadnezhad

2014-02-01

65

Neuromuscular electrical stimulation in critically ill patients in the intensive care unit: a systematic review / Estimulação elétrica neuromuscular em pacientes graves em unidade de terapia intensiva: revisão sistemáticaNeuromuscular electrical stimulation in critically ill patients in the intensive care unit: a systematic review  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Objetivo Analisar os desfechos propiciados pela estimulação elétrica neuromuscular em pacientes graves assistidos em unidade de terapia intensiva. Métodos Revisão sistemática da literatura, por meio de ensaios clínicos publicados entre 2002 e 2012 nas bases de dados LILACS, SciELO, MedLine e PE [...] Dro, usando os descritores “intensive care unit”, “physical therapy”, “physiotherapy”, “electric stimulation” e “randomized controlled trials”. Resultados Foram incluídos quatro ensaios clínicos. O tamanho amostral variou entre 8 a 33 sujeitos, de ambos os gêneros, com média de idade variando entre 52 e 79 anos, submetidos à ventilação mecânica invasiva. Dos artigos analisados, três indicaram benefícios significativos da estimulação elétrica neuromuscular em pacientes graves, como melhora na força muscular periférica, capacidade de exercício, funcionalidade ou espessura de perda da camada muscular. Conclusão A aplicação de estimulação elétrica neuromuscular promove uma resposta benéfica em pacientes graves em terapia intensiva. Objective To analyze the outcomes enabled by the neuromuscular electric stimulation in critically ill patients in intensive care unit assisted. Methods A systematic review of the literature by means of clinical trials published between 2002 and 2012 in the databases LILACS, SciELO, MEDLINE and PEDro using the descriptors “intensive care unit”, “physical therapy”, “physiotherapy”, “electric stimulation” and “randomized controlled trials”. Results We included four trials. The sample size varied between 8 to 33 individuals of both genders, with ages ranging between 52 and 79 years, undergoing invasive mechanical ventilation. Of the articles analyzed, three showed significant benefits of neuromuscular electrical stimulation in critically ill patients, such as improvement in peripheral muscle strength, exercise capacity, functionality, or loss of thickness of the muscle layer. Conclusion The application of neuromuscular electrical stimulation promotes a beneficial response in critically patients in intensive care. Abstract in english Objective To analyze the outcomes enabled by the neuromuscular electric stimulation in critically ill patients in intensive care unit assisted. Methods A systematic review of the literature by means of clinical trials published between 2002 and 2012 in the databases LILACS, SciELO, MEDLINE and [...] PEDro using the descriptors “intensive care unit”, “physical therapy”, “physiotherapy”, “electric stimulation” and “randomized controlled trials”. Results We included four trials. The sample size varied between 8 to 33 individuals of both genders, with ages ranging between 52 and 79 years, undergoing invasive mechanical ventilation. Of the articles analyzed, three showed significant benefits of neuromuscular electrical stimulation in critically ill patients, such as improvement in peripheral muscle strength, exercise capacity, functionality, or loss of thickness of the muscle layer. Conclusion The application of neuromuscular electrical stimulation promotes a beneficial response in critically patients in intensive care.

Lucas Lima, Ferreira; Luiz Carlos Marques, Vanderlei; Vitor Engrácia, Valenti.

2014-09-01

66

Control rod drive mechanism  

International Nuclear Information System (INIS)

Purpose: To ensure the scram operation of a control rod by the reliable detection for the position of control rods. Constitution: A permanent magnet is provided to the lower portion of a connecting rod in engagement with a control rod and a tube having a plurality of lead switches arranged axially therein in a predetermined pitch is disposed outside of the control rod drives. When the control rod moves upwardly in the scram operation, the lead switches are closed successively upon passage of the permanent magnet to operate the electrical circuit provided by way of each of the lead switches. Thus, the position for the control rod during the scram can reliably be determined and the scram characteristic of the control rod can be recognized. (Furukawa, Y.)

67

RAPID NONDESTRUCTIVE MECHANICAL STRESS CONTROL  

Directory of Open Access Journals (Sweden)

Full Text Available The paper considers problems of nondestructive mechanical stress control device design. An analytical expression for calculation of EMF induced in the measuring winding of a converter is obtained. The automatic control system developed linearizes the converter output voltage versus mechanical intensity.

O.V. Nabokova

2013-02-01

68

RAPID NONDESTRUCTIVE MECHANICAL STRESS CONTROL  

OpenAIRE

The paper considers problems of nondestructive mechanical stress control device design. An analytical expression for calculation of EMF induced in the measuring winding of a converter is obtained. The automatic control system developed linearizes the converter output voltage versus mechanical intensity.

Nabokova, O. V.; Kozlov, V. V.; Bezotosniy, V. F.

2013-01-01

69

Control rod drive mechanism  

International Nuclear Information System (INIS)

Purpose: To enhance the drive performance of a control rod drive (CRD) and the reliability of the CRD in joining and separating functions with a control rod (CR) by sufficiently enclosing the top of a hollow piston. Constitution: A flange having a bolt hole for mounting a control rod drive (CRD) in a CRD housing is provided at the lower portion of the CRD. A piston tube is arranged at the center of the CRD, and a sealer is mounted at the joint between the piston tube and the inner face of the flange. On the other hand, a hollow piston is engaged between the hollow piston and a cylinder tube, and a sealer for sealing the space of the cylinder tube is mounted at the lower portion of the hollow piston. Further, a joining member with the control rod is mounted at the top of the hollow piston. (Yoshino, Y.)

70

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

Science.gov (United States)

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. PMID:25228853

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

71

Control rod drive mechanism  

International Nuclear Information System (INIS)

Purpose: To improve security of the reactor by holding in the reactor core the control rods without functions of emergency insertion in the control rod drives for the BWR type reactors. Constitution: When the pressure switch to detect pressure in the accumulator and the pressure vessel is installed and such pressure is decreased to pressure by which the control rods cannot be inserted on scram within a given period of time, the feed water valve of the feed pipe from the accumulator is opened and the control rods are inserted into the reactor core by accumulator-applied pressure. The feed valve and the drain valve are held in the closed condition when pressure inside the accumulator and the pressure vessel is lowered. Accordingly, the reactor can be improved in safety by previously inserting in the core those control rods for which pressure for emergency insertion cannot be obtained, or by prohibiting more drawing of the rods staying in a half-drawn position. (Kamimura, M.)

72

Kinesio Taping(®) does not alter neuromuscular performance of femoral quadriceps or lower limb function in healthy subjects: randomized, blind, controlled, clinical trial.  

Science.gov (United States)

The aim of this study was to analyze the immediate effects of applying Kinesio Taping(®) (KT) on the neuromuscular performance of femoral quadriceps, postural balance and lower limb function in healthy subjects. This is a randomized, blind, controlled, clinical trial, where sixty female volunteers (age: 23.3 ± 2.5 years; BMI: 22.2 ± 2.1 kg/m(2)) were randomly assigned to three groups of 20 subjects each: control (10 min at rest); nonelastic adhesive tape (application over the rectus femoris, vastus lateralis and vastus medialis muscles); and KT (KT application over the same muscles). All individuals were assessed for single and triple hops, postural balance (by baropodometry), peak concentric and eccentric torque and electromyographic activity of vastus lateralis, before and after interventions. No significant differences in electromyographic activity of the VL or concentric and eccentric knee peak torque were recorded, between groups and initial and final assessment in any of the three groups. We also observed no significant alteration in single and triple-hop distance and one-footed static balance between the three groups. Application of KT to RF, VL and VM muscles did not significantly change lower limb function, postural balance, knee extensor peak torque or electromyographic activity of VL muscle in healthy women. PMID:22796389

Lins, Caio Alano de Almeida; Neto, Francisco Locks; Amorim, Anita Barros Carlos de; Macedo, Liane de Brito; Brasileiro, Jamilson Simões

2013-02-01

73

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  

OpenAIRE

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 conditio...

Peltier Sébastien L; Vincent Lucile; Millet Guillaume Y; Sirvent Pascal; Morin Jean-Benoît; Guerraz Michel; Geyssant André; Lescuyer Jean-François; Feasson Léonard; Messonnier Laurent

2011-01-01

74

Neuromuscular control of hovering wingbeat kinematics in response to distinct flight challenges in the ruby-throated hummingbird, Archilochus colubris.  

Science.gov (United States)

While producing one of the highest sustained mass-specific power outputs of any vertebrate, hovering hummingbirds must also precisely modulate the activity of their primary flight muscles to vary wingbeat kinematics and modulate lift production. Although recent studies have begun to explore how pectoralis (the primary downstroke muscle) neuromuscular activation and wingbeat kinematics are linked in hummingbirds, it is unclear whether different species modulate these features in similar ways, or consistently in response to distinct flight challenges. In addition, little is known about how the antagonist, the supracoracoideus, is modulated to power the symmetrical hovering upstroke. We obtained simultaneous recordings of wingbeat kinematics and electromyograms from the pectoralis and supracoracoideus in ruby-throated hummingbirds (Archilochus colubris) hovering under the following conditions: (1) ambient air, (2) air density reduction trials, (3) submaximal load-lifting trials and (4) maximal load-lifting trials. Increased power output was achieved through increased stroke amplitude during air density reduction and load-lifting trials, but wingbeat frequency only increased at low air densities. Overall, relative electromyographic (EMG) intensity was the best predictor of stroke amplitude and is correlated with angular velocity of the wingtip. The relationship between muscle activation intensity and kinematics was independent of treatment type, indicating that reduced drag on the wings in hypodense air did not lead to high wingtip angular velocities independently of increased muscle work. EMG bursts consistently began and ended before muscle shortening under all conditions. During all sustained hovering, spike number per burst consistently averaged 1.2 in the pectoralis and 2.0 in the supracoracoideus. The number of spikes increased to 2.5-3 in both muscles during maximal load-lifting trials. Despite the relative kinematic symmetry of the hovering downstroke and upstroke, the supracoracoideus was activated ~1 ms earlier, EMG bursts were longer (~0.9 ms) and they exhibited 1.6 times as many spikes per burst. We hypothesize that earlier and more sustained activation of the supracoracoideus fibres is necessary to offset the greater compliance resulting from the presence of the supracoracoid tendon. PMID:23948477

Mahalingam, Sajeni; Welch, Kenneth C

2013-11-15

75

[Effect of whole body vibration on the neuromuscular performance of females 65 years and older. One-year results of the controlled randomized ELVIS study].  

Science.gov (United States)

Sarcopenia is linked to an increased risk of morbidity and mortality in the aging. Whole body vibration (WBV) exercises are currently discussed as a "gentle" alternative to conventional exercises to improve muscle mass. The present study scrutinized whether a multipurpose (exercise) training program using WBV can improve muscle mass and neuromuscular capacity, while lowering fall risk. A total of 151 postmenopausal women were randomized into three groups: exercise group (TG), exercise group with vibration (VTG), and fitness control group (CG). The TG group participated in an exercise program including leg strengthening training twice a week over 12 months, while the VTG carried out an identical program with the leg exercises performed under WBV. Despite a positive trend regarding lean body mass in the two exercise groups, there was no difference between groups. Both exercise groups showed a significant increase (vs. KG) in trunk strength. An improvement in both exercise groups was also measured with respect to leg strength, but only the VTG showed significant differences compared to the CG. In addition, a significant lower risk of falls compared with the CG was evident only in VTG. PMID:19789832

Kemmler, W; V Stengel, S; Mayer, S; Niedermayer, M; Hentschke, C; Kalender, W A

2010-04-01

76

Nervous mechanisms of postural control  

OpenAIRE

Maintenance of body confguration and orientation in space (postural control) is a vital motor function. A general goal of the present study was to analyze nervous feedback mechanisms for the maintenance of posture during different motor behaviors and with different postural perturbations. Different aspects of postural control were considered in this study: (i) the postural motor responses during standing and locomotion, (ii) the role of supraspinal systems (cortico- and r...

Karayannidou, Anastasia

2009-01-01

77

Influence of intense neuromuscular blockade on surgical conditions during laparotomy : a pig model  

DEFF Research Database (Denmark)

PURPOSE: Intense neuromuscular block may improve surgical conditions in ileus laparotomies; however, it is difficult to evaluate. The aim of this study was to investigate if neuromuscular block improved surgical conditions in pigs with artificial ileus laparotomy. METHODS: Six pigs were endotracheally intubated, mechanically ventilated, anesthetized with propofol and fentanyl, and randomized into two groups in a cross-over assessor-blinded design. Neuromuscular block was established with rocuronium. Artificial laparotomy for ileus was performed. We investigated the influence of intense 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 suctioning the lungs at intense neuromuscular block. Without neuromuscular block we detected abdominal contractions seen as hiccups and bucking. In all six pigs during intense neuromuscular block we found no visible electromyographic (EMG) activity in the abdominal muscles while suctioning the lungs. Without neuromuscular block suctioning the lungs elicited brief periods of abdominal EMG activity. No difference was found in the force needed to close the fascia when comparing no neuromuscular block with intense neuromuscular block. Furthermore, no significant differences were found in the width of the diastase, 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 not influence the force needed to close the fascia.

Madsen, Matias Vested; Donatsky, Anders Meller

2015-01-01

78

Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation  

OpenAIRE

Abstract Background The purpose of this study was to determine the comparative effectiveness of feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). Methods In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensio...

Nataraj Raviraj; Audu Musa L; Triolo Ronald J

2012-01-01

79

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

OpenAIRE

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 c...

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

2010-01-01

80

Impaired neuromuscular transmission and skeletal muscle fiber necrosis in mice lacking Na/Ca exchanger 3  

OpenAIRE

We produced and analyzed mice deficient for Na/Ca exchanger 3 (NCX3), a protein that mediates cellular Ca(2+) efflux (forward mode) or Ca(2+) influx (reverse mode) and thus controls intracellular Ca(2+) concentration. NCX3-deficient mice (Ncx3(-/-)) present a skeletal muscle fiber necrosis and a defective neuromuscular transmission, reflecting the absence of NCX3 in the sarcolemma of the muscle fibers and at the neuromuscular junction. The defective neuromuscular transmission is characterized...

Sokolow, S.; Manto, M.; Gailly, P.; Molgo?, J.; Vandebrouck, C.; Vanderwinden, J. M.; Herchuelz, A.; Schurmans, Ste?phane

2004-01-01

81

Optimal Control of Mechanical Systems  

Directory of Open Access Journals (Sweden)

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.

Vadim Azhmyakov

2007-08-01

82

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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese CONTEXTUALIZAÇÃO: 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 tratamen [...] to 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 avaliação funcional dos músculos do assoalho pélvico (MAP) foi realizada por meio de perineometria, e a severidade dos sinais e sintomas da IUE foi avaliada, objetivamente, pelo pad test de uma hora e, subjetivamente, pela Escala Visual Analógica (EVA), que mediu o desconforto causado pela incontinência. Para a análise de normalidade dos dados, utilizou-se o teste Shapiro-Wilk, seguido do teste de Friedman para dados não paramétricos. Para a análise dos sintomas relacionados à IUE, usaram-se os testes Exato de Fisher e Mann-Whitney. Em todas as análises, considerou-se o nível de significância de 5%. RESULTADOS: Não houve diferença significativa (p>0,05) entre os grupos em nenhuma variável avaliada. Na comparação intragrupos das avaliações iniciais e finais (após EENM), houve diferença significativa (p Abstract in english 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. METHOD [...] S: 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 (p

Priscila G. J. M., Alves; Fabiana R., Nunes; Elaine C. O., Guirro.

2011-10-01

83

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)

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 avaliação funcional dos músculos do assoalho pélvico (MAP foi realizada por meio de perineometria, e a severidade dos sinais e sintomas da IUE foi avaliada, objetivamente, pelo pad test de uma hora e, subjetivamente, pela Escala Visual Analógica (EVA, que mediu o desconforto causado pela incontinência. Para a análise de normalidade dos dados, utilizou-se o teste Shapiro-Wilk, seguido do teste de Friedman para dados não paramétricos. Para a análise dos sintomas relacionados à IUE, usaram-se os testes Exato de Fisher e Mann-Whitney. Em todas as análises, considerou-se o nível de significância de 5%. RESULTADOS: Não houve diferença significativa (p>0,05 entre os grupos em nenhuma variável avaliada. Na comparação intragrupos das avaliações iniciais e finais (após EENM, houve diferença significativa (p<0,05 na quantidade de urina perdida, no desconforto causado pela incontinência urinária e na pressão perineal. CONCLUSÃO: Os procedimentos de EENM utilizados neste estudo foram igualmente eficazes no tratamento da IUE.

Priscila G. J. M. Alves

2011-10-01

84

Novel vibration-exercise instrument with dedicated adaptive filtering for electromyographic investigation of neuromuscular activation.  

Science.gov (United States)

Vibration exercise (VE) has been suggested as an effective methodology to improve muscle strength and power performance. Several studies link the effects of vibration training to enhanced neuromuscular demand, typically ascribed to involuntary reflex mechanisms. However, the underlying mechanisms are still unclear, limiting the identification of the most appropriate vibration training protocols. This study concerns the realization of a new vibration exercise system for the upper limbs. Amplitude, frequency, and baseline of the vibrating force, which is generated by an electromechanical actuator, can be adjusted independently. A second order model is employed to identify the relation between the generated force and the input voltage driving the actuator. Our results show a high correlation (0.99) between the second order model fit and the measured data, ensuring accurate control on the supplied force. The level of neuromuscular demand imposed by the system on the targeted muscles can be estimated by electromyography (EMG). However, EMG measurements during VE can be severely affected by motion artifacts. An adaptive least mean square algorithm is proposed to remove motion artifacts from the measured EMG data. Preliminary validation with seven volunteers showed excellent motion artifact removal, enabling reliable evaluation of the neuromuscular activation. PMID:23033335

Xu, Lin; Rabotti, Chiara; Mischi, Massimo

2013-03-01

85

A Nanoscale Mechanism for Protein Control  

Science.gov (United States)

... Press Release 05-026A Nanoscale Mechanism for Protein Control The nanoscale spring-loaded control ... National Science Foundation have created a nanoscale mechanism to control the function of virtually ...

86

Patología neuromuscular en cuidados intensivos Neuromuscular abnormalities in critical illness  

Directory of Open Access Journals (Sweden)

Full Text Available La patología neuromuscular en los pacientes críticos ha comenzado a ser objeto de un importante número de estudios en los últimos años, si bien aún quedan muchas lagunas en el conocimiento de su etiología, patogenia, tratamiento y pronóstico. Dentro de esta patología debemos distinguir dos grandes grupos. En el primero, la debilidad muscular aparece antes del ingreso en UCI y es posible identificar una causa conocida. El síndrome de Guillain-Barré y la miastenia grave son las dos entidades que con mayor frecuencia requieren ser atendidas en nuestras unidades. En el segundo grupo, la debilidad muscular se adquiere en la UCI, en pacientes sin enfermedad neuromuscular previa, y es secundaria a la gravedad de la enfermedad que originó su ingreso en esta unidad y/o al tratamiento empleado. La polineuropatía del paciente crítico (PPC es, de todas ellas, la entidad más precisamente definida y de la que conocemos mejor sus características clínicas, diagnóstico y pronóstico; no obstante, aún quedan muchas sombras en cuanto a su etiopatogenia. Las alteraciones de la placa neuromuscular y sobre todo la miopatía, que frecuentemente coexiste con la PPC, son las otras complicaciones del sistema nervioso periférico que se desarrollan en pacientes críticos. Los avances en el conocimiento de estas afecciones podrían tener un importante impacto, sobre todo para el desarrollo de intervenciones terapéuticas y preventivas efectivas que mejoren el pronóstico de estos pacientes.The spectrum of neuromuscular disease encountered in today's intensive care units (ICU has evolved over the last few decades. However, in spite of many studies on neuromuscular disorders complicating critical illness as well as its epidemiology, etiology, treatment and prognosis, several key areas remain unclear. Two main groups are found among these neuromuscular abnormalities. The first group includes primary neuromuscular disorders present on admission to the ICU in which a possible etiology can be identified. Guillain-Barré syndrome and myasthenia gravis are two of the most common diseases admitted to ours units. In the second group, weakness is acquired in the ICU in the absence of preexisting neuromuscular disease. It is believed to reflect illnesses or treatments occurring in the ICU. Critical illness polyneuropathy (CIP is the most clearly defined neuromuscular complication in this group. However, although we have better knowledge of its clinical, diagnosis, and prognosis features, its pathophysiological substrate has not been fully elucidated. Neuromuscular junction defects and specially myopathies, that frequently coexist with CIP, are the others main causes of acquired weakness in critically ill patients. Advances in understanding of these neuromuscular disorders could have an important impact in terms of developing effective preventive and therapeutic interventions that could help to improve the poor prognosis of these patients.

R. Amaya Villar

2009-04-01

87

Neuromuscular adaptation to actual and simulated weightlessness  

Science.gov (United States)

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.

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

1994-01-01

88

Immune mechanisms of HIV control.  

Science.gov (United States)

HIV-1 can be contained by the immune system, as demonstrated by the existence of rare individuals who spontaneously control HIV-1 replication in the absence of antiretroviral therapy. Emerging evidence points to the importance of a very active cellular immune response in mediating HIV-1 control. The rapid induction of interferon-dependent HIV restriction factors, the presence of protective MHC class I alleles, and the development of a high avidity T-cell response may all cooperate in limiting HIV replication at an early stage. This review will focus on recent advances in understanding the immune mechanisms of HIV control, and on the lessons that may be drawn for the development of candidate HIV vaccines. PMID:20650621

Chakrabarti, Lisa A; Simon, Viviana

2010-08-01

89

Age-related changes in trunk neuromuscular activation patterns during a controlled functional transfer task include amplitude and temporal synergies.  

Science.gov (United States)

While healthy aging is associated with physiological changes that can impair control of trunk motion, few studies examine how spinal muscle responses change with increasing age. This study examined whether older (over 65years) compared to younger (20-45years) adults had higher overall amplitude and altered temporal recruitment patterns of trunk musculature when performing a functional transfer task. Surface electromyograms from twelve bilateral trunk muscle (24) sites were analyzed using principal component analysis, extracting amplitude and temporal features (PCs) from electromyographic waveforms. Two PCs explained 96% of the waveform variance. Three factor ANOVA models tested main effects (group, muscle and reach) and interactions for PC scores. Significant (panalysis revealed that relative to younger adults, older adults recruited higher agonist and antagonistic activity, demonstrated continuous activation levels in specific muscle sites despite changing external moments, and had altered temporal synergies within abdominal and back musculature. In summary both older and younger adults recruit highly organized activation patterns in response to changing external moments. Differences in temporal trunk musculature recruitment patterns suggest that older adults experience different dynamic spinal stiffness and loading compared to younger adults during a functional lifting task. PMID:25457424

Quirk, D Adam; Hubley-Kozey, Cheryl L

2014-12-01

90

Expecting ankle tilts and wearing an ankle brace influence joint control in an imitated ankle sprain mechanism during walking.  

Science.gov (United States)

A thorough understanding of the functional aspects of ankle joint control is essential to developing effective injury prevention. It is of special interest to understand how neuromuscular control mechanisms and mechanical constraints stabilize the ankle joint. Therefore, the aim of the present study was to determine how expecting ankle tilts and the application of an ankle brace influence ankle joint control when imitating the ankle sprain mechanism during walking. Ankle kinematics and muscle activity were assessed in 17 healthy men. During gait rapid perturbations were applied using a trapdoor (tilting with 24° inversion and 15° plantarflexion). The subjects either knew that a perturbation would definitely occur (expected tilts) or there was only the possibility that a perturbation would occur (potential tilts). Both conditions were conducted with and without a semi-rigid ankle brace. Expecting perturbations led to an increased ankle eversion at foot contact, which was mediated by an altered muscle preactivation pattern. Moreover, the maximal inversion angle (-7%) and velocity (-4%), as well as the reactive muscle response were significantly reduced when the perturbation was expected. While wearing an ankle brace did not influence muscle preactivation nor the ankle kinematics before ground contact, it significantly reduced the maximal ankle inversion angle (-14%) and velocity (-11%) as well as reactive neuromuscular responses. The present findings reveal that expecting ankle inversion modifies neuromuscular joint control prior to landing. Although such motor control strategies are weaker in their magnitude compared with braces, they seem to assist ankle joint stabilization in a close-to-injury situation. PMID:24365326

Gehring, Dominic; Wissler, Sabrina; Lohrer, Heinz; Nauck, Tanja; Gollhofer, Albert

2014-03-01

91

Neuromuscular disease and extubation dysphagia  

OpenAIRE

Post-extubation dysphagia is a common and serious problem. The presence of neuromuscular disease at the time of intubation is likely to increase this. Until recently, the prevalence and the association with length of intubation had not been clarified. Results published in this journal suggest that 93% of extubated patients with neuromuscular disease had post-extubation dysphagia, which in 33% of cases was considered severe. The number of days ventilated was the single predictor of severe dysp...

Smithard, David G.

2013-01-01

92

Control mechanisms for ecological-economic systems  

CERN Document Server

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.

Burkov, Vladimir N; Shchepkin, Alexander V

2015-01-01

93

Cellular mechanisms that control mistranslation  

DEFF Research Database (Denmark)

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 at the molecular level and has led to the discovery that the rates of mistranslation in vivo are not fixed but instead are variable. In this Review we describe the different steps in translation quality control and their variations under different growth conditions and between species though a comparison of in vitro and in vivo findings. This provides new insights as to why mistranslation can have both positive and negative effects on growth and viability.

Reynolds, Noah M; Lazazzera, Beth A

2010-01-01

94

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)

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

Peltier Sébastien L

2011-12-01

95

Neuromuscular disease classification system  

Science.gov (United States)

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.

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

2013-06-01

96

Control of a mechanical gripper with a fuzzy controller  

International Nuclear Information System (INIS)

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)

97

Mechanisms of selective mechanical weed control by harrowing  

OpenAIRE

Keywords: weed harrowing, mechanical weed control, selectivity, biomechanics, uprooting, soil-covering, recovery, plant damage, methodology Current weed control problems in organic farming and minor crops show that alternatives for selective herbicides need further development. Mechanical control methods such as weed harrowing are attractive because of the high capacity, wide applicability and low cost. However, the variable effectiveness a...

Kurstjens, D. A. G.

2002-01-01

98

Effects of neuromuscular deprogramming on the head position.  

Science.gov (United States)

Objectives: The aim of this study was to evaluate the effects of the neuromuscular deprogramming of the mandible on the craniocervical position. Methods: Participants (n?=?65) were separated into two groups: 25 untreated controls (10 men and 15 women) and 40 patients (17 men and 23 women) and underwent neuromuscular deprogramming with upper occlusal splints for an average of 6 months and 7 days, before orthodontic treatment. Lateral cephalograms were obtained from each subject in the natural head position (NHP), before and after neuromuscular deprogramming. Craniocervical cephalometric analysis was performed to evaluate craniovertical (NSL/VER), craniocervical (OPT/NSL and CVT/NSL), and cervicohorizontal (OPT/HOR and CVT/HOR) angulation, and the angle of the cervical curvature (OPT/CVT). Results: After neuromuscular deprogramming, significant changes in three angles - NSL/VER (PCVT/NSL (P<0·001) - were found between the two groups. For the cervical spine position, no significant changes were observed. Conclusion: The results indicate that neuromuscular deprogramming using occlusal splinting causes significant extension of the head. PMID:25052029

Andrighetto, Augusto Ricardo; Fantini, Solange Mongelli de

2014-07-22

99

Impairment of diaphragm muscle force and neuromuscular transmission after normothermic cardiopulmonary bypass: effect of low-dose inhaled CO  

OpenAIRE

Cardiopulmonary bypass (CPB) is associated with significant postoperative morbidity, but its effects on the neuromuscular system are unclear. Recent studies indicate that even relatively short periods of mechanical ventilation result in significant neuromuscular effects. Carbon monoxide (CO) has gained recent attention as therapy to reduce the deleterious effects of CPB. We hypothesized that 1) CPB results in impaired neuromuscular transmission and reduced diaphragm force generation; and 2) C...

Ermilov, Leonid G.; Pulido, Juan N.; Atchison, Fawn W.; Zhan, Wen-zhi; Ereth, Mark H.; Sieck, Gary C.; Mantilla, Carlos B.

2010-01-01

100

Patología neuromuscular en cuidados intensivos / Neuromuscular abnormalities in critical illness  

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish La patología neuromuscular en los pacientes críticos ha comenzado a ser objeto de un importante número de estudios en los últimos años, si bien aún quedan muchas lagunas en el conocimiento de su etiología, patogenia, tratamiento y pronóstico. Dentro de esta patología debemos distinguir dos grandes g [...] rupos. En el primero, la debilidad muscular aparece antes del ingreso en UCI y es posible identificar una causa conocida. El síndrome de Guillain-Barré y la miastenia grave son las dos entidades que con mayor frecuencia requieren ser atendidas en nuestras unidades. En el segundo grupo, la debilidad muscular se adquiere en la UCI, en pacientes sin enfermedad neuromuscular previa, y es secundaria a la gravedad de la enfermedad que originó su ingreso en esta unidad y/o al tratamiento empleado. La polineuropatía del paciente crítico (PPC) es, de todas ellas, la entidad más precisamente definida y de la que conocemos mejor sus características clínicas, diagnóstico y pronóstico; no obstante, aún quedan muchas sombras en cuanto a su etiopatogenia. Las alteraciones de la placa neuromuscular y sobre todo la miopatía, que frecuentemente coexiste con la PPC, son las otras complicaciones del sistema nervioso periférico que se desarrollan en pacientes críticos. Los avances en el conocimiento de estas afecciones podrían tener un importante impacto, sobre todo para el desarrollo de intervenciones terapéuticas y preventivas efectivas que mejoren el pronóstico de estos pacientes. Abstract in english The spectrum of neuromuscular disease encountered in today's intensive care units (ICU) has evolved over the last few decades. However, in spite of many studies on neuromuscular disorders complicating critical illness as well as its epidemiology, etiology, treatment and prognosis, several key areas [...] remain unclear. Two main groups are found among these neuromuscular abnormalities. The first group includes primary neuromuscular disorders present on admission to the ICU in which a possible etiology can be identified. Guillain-Barré syndrome and myasthenia gravis are two of the most common diseases admitted to ours units. In the second group, weakness is acquired in the ICU in the absence of preexisting neuromuscular disease. It is believed to reflect illnesses or treatments occurring in the ICU. Critical illness polyneuropathy (CIP) is the most clearly defined neuromuscular complication in this group. However, although we have better knowledge of its clinical, diagnosis, and prognosis features, its pathophysiological substrate has not been fully elucidated. Neuromuscular junction defects and specially myopathies, that frequently coexist with CIP, are the others main causes of acquired weakness in critically ill patients. Advances in understanding of these neuromuscular disorders could have an important impact in terms of developing effective preventive and therapeutic interventions that could help to improve the poor prognosis of these patients.

R., Amaya Villar; J., Garnacho-Montero; M.D., Rincón Ferrari.

2009-04-01

101

Neuromuscular activity and knee kinematics in adolescents with patellofemoral pain  

DEFF Research Database (Denmark)

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).

Rathleff, Michael Skovdal; Samani, Afshin

2013-01-01

102

Neuromuscular Activity and Knee Kinematics in Adolescents with Patellofemoral Pain  

DEFF Research Database (Denmark)

: Purpose: To investigate neuromuscular control of the knee during stair descent among female adolescents with Patellofemoral Pain (PFP) and report its association with self-reported clinical status assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS).Methods: Fifty-seven previously untreated female adolescents diagnosed with PFP aged 15 to 19 years were recruited from schools. The control group consisted of 29 age-matched healthy female adolescents. Bipolar surface electrodes were placed on VM and VL and an electronic knee goniometer was placed at the knee to collect knee flexion/extension kinematics. The participants walked down a stairway consisting of 24 steps at their normal pace. Sample Entropy was used to quantify the complexity of the time series from surface electromyography (sEMG) and kinematics during the stance phase. Self-reported clinical status was assessed by the KOOS and maximal quadriceps torque measured using strap-mounted handheld dynamometry.Results: Female adolescents withPFP were characterized by altered neuromuscular knee control during stair descent, lower maximal quadriceps torque, and poorer KOOS scores across all five domains. Furthermore, a positive association was found between the complexity of sEMG from VL and self-reported pain determined by KOOSpain indicating larger impairments in neuromuscular knee control among those with the highest pain levels.Conclusion: The current findings show that female adolescents with PFP are characterized by altered neuromuscular control of the knee during stair descent and lower maximal quadriceps torque. These results suggest that rehabilitation is needed, and should focus on restoring neuromuscular control and muscle strength.

Rathleff, Michael Skovdal; Samani, Afshin

2013-01-01

103

Teacher's Guide to Neuromuscular Disease  

Science.gov (United States)

... ages who are living with neuromuscular diseases. MDA Publications Department © 2005, Muscular Dystrophy Association Give Now. Ways To Help Advocacy Become a Volunteer Charitable Giving Donor Login MDA Programs Matching Gifts About MDA Contact MDA Become a Volunteer Careers FAQ MDA Internships ...

104

Role of fatigue in limiting physical activities in humans with neuromuscular diseases.  

Science.gov (United States)

New methods of examining both central and peripheral fatigue are now available. A broader understanding of the mechanisms of fatigue in healthy human subjects has begun to emerge. The mechanisms of fatigue in patients with various neuromuscular diseases are even more complex than in healthy persons. Examples of both central and peripheral fatigue in various neuromuscular diseases and other disorders are presented, including metabolic myopathy, chronic fatigue syndrome, postpolio syndrome, and amyotrophic lateral sclerosis. PMID:12409815

Miller, Robert G

2002-11-01

105

Effect of ulinastatin on the rocuronium-induced neuromuscular blockade  

Science.gov (United States)

Background Ulinastatin is a glycoprotein derived from human urine and a serine protease inhibitor found in human urine and blood. Ulinastatin increases both liver blood flow and urine output. Rocuronium is eliminated mainly through the liver and partly through the kidney, hepatic elimination of rocuronium might be enhanced by ulinastatin. We examined the effect of ulinastatin on the neuromuscular block caused by rocuronium. Methods Forty four adult patients were randomly divided into two groups of 22 patients each, i.e. the study group and the control group. In the study group, a bolus dose of ulinastatin 5,000 U/kg was administered 2 min before the injection of rocuronium 0.6 mg/kg. In the control group, normal saline was administered instead of ulinastatin. For the monitoring of both onset and recovery from neuromuscular blockade, train-of-four (TOF) and post-tetanic count were used with TOF-Watch Sx. All patients underwent general anesthesia with total intravenous anesthesia (TIVA) of remifentanil and propofol, using the effect site target infusion system. Results In the study group, the onset of neuromuscular block was significantly slower than in the control group (P Ulinastatin significantly delays the onset of neuromuscular block and accelerates the recovery from the block caused by rocuronium. PMID:22474550

Kim, Min Soo; Park, Jung Woo; Yoo, Byung Hoon; Yon, Jun Heum; Kim, Dong Won

2012-01-01

106

Recovery of neuromuscular junction morphology following 16 days of spaceflight.  

Science.gov (United States)

It has previously been established that spaceflight elicits alterations in the morphology of the neuromuscular system that includes expansion of the neuromuscular junction (NMJ) and myofiber atrophy. The purpose of this study was to determine the capacity of the neuromuscular system to recover from spaceflight-induced modifications upon return to normal gravity. Soleus muscles were obtained from rats participating in the 16-day Neurolab space shuttle mission at 1 day and 14 days after returning to Earth: solei were also taken at the same time points from ground-based control rats. Cytofluorescent techniques, coupled with confocal microscopy, were used to assess NMJ morphology. Histochemistry, in conjunction with phase contrast microscopy, was employed to examine myofiber size and type. Results indicate that 1 day after landing both pre- and postsynaptic stained areas of the NMJ were significantly (P < or = 0.05) larger in the spaceflight group than in controls. Moreover, significant myofiber atrophy was demonstrated in animals subjected to 0 gravity. By 14 days following return to the Earth, however, NMJ stained areas and muscle fiber size were no longer different from control values at that same interval. These results suggest that the neuromuscular system possesses a robust capacity to recover from spaceflight-induced perturbations upon return to normal gravitational influences. PMID:11746714

Deschenes, M R; Britt, A A; Gomes, R R; Booth, F W; Gordon, S E

2001-12-01

107

Autoimmune disorders of the neuromuscular junction  

Directory of Open Access Journals (Sweden)

Full Text Available The neuromuscular junction (NMJ is a specialized synapse with a complex structural and functional organization. It is a target for a variety of immunological disorders and these diseases usually respond well to immunotherapies. The understanding of the immunological basis of myasthenia gravis, the most common neuromuscular junction disorder, has improved in the recent years. Most patients have antibodies to the acetylcholine receptor (AChR, but around 10% have AChR antibodies that are only identified by novel methods, and up to 5% have muscle-specific kinase antibodies which define a different subgroup of myasthenia. The spectrum of antibodies and their pathophysiological aspects are being elucidated. Even though less common, Lambert Eaton myasthenic syndrome (LEMS is important to recognize. The abnormality in LEMS is a presynaptic failure to release enough packets of ACh, caused by antibodies to the presynaptic voltage-gated calcium channels. More than half these patients have a small cell carcinoma of lung. Acquired neuromyotonia (NMT is a condition associated with muscle hyperactivity. Clinical features include muscle stiffness, cramps, myokymia, pseudomyotonia and weakness. The immune mechanisms of acquired NMT relate to loss of voltage-gated potassium channel function. This review will focus on the important recent developments in the immune-mediated disorders of the NMJ.

Vincent Angela

2008-01-01

108

Development of a neuromuscular junction model on surfaces modified by plasma polymerization / Desarrollo de un modelo de unión neuromuscular sobre superficies modificadas por polimerización por plasma  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish El objetivo de este trabajo es implementar un modelo biológico de unión neuromuscular para el estudio de los mecanismos involucrados en los procesos intra e intercelulares empleando co-cultivos celulares. Con el fin de optimizar el crecimiento y desarrollo de las uniones neuromusculares, las células [...] se cultivaron sobre superficies de polipirrol obtenidas mediante polimerización por plasma que han mostrado ser adecuadas en otros tipos de cultivos celulares. Las líneas celulares que se emplearon fueron los modelos de motoneurona NG108-15 y muscular C2C12. Las células se evaluaron de acuerdo a su morfología y características electrofisiológicas. Para observar la expresión de proteínas clave de la sinapsis, se aplicaron técnicas inmunocitoquímicas utilizando anticuerpos específicos para la marcación de proteínas localizadas en las terminales nerviosas adquiriendo imágenes con microscopía de fluorescencia. Las imágenes de los co-cultivos celulares mostraron la formación de uniones neuromusculares. El método de preparación de uniones neuromusculares que se describe en este trabajo permitirá estudiar los mecanismos involucrados en sus funciones. Abstract in english The aim of this work is to implement a biological model of neuromuscular junctions to study the mechanisms involved in intra and inter cellular processes using cell co-cultures. To optimize growth and development of the neuromuscular junction, cells were seeded on plasma polymerized pyrrole which ha [...] s proven suitable for other types of cell cultures. The cell lines used were motor neuron NG108-15 and skeletal muscle C2C12. Cells were evaluated according to their morphology and electrophysiological characteristics. To observe the expression of specific proteins of the nerve synapse, immunocytochemical techniques were applied using dying antibodies. Proteins localized in nerve terminals were dyed and imaged by fluorescence microscopy. Images of cell co-cultures showed the formation of neuromuscular junctions. The preparation of neuromuscular junctions described in this work will allow the study of the mechanisms involved in their functions.

E., Zuñiga-Aguilar; R., Godínez; O., Ramírez-Fernández; J., Morales; R., Olayo.

109

Apamin reduces neuromuscular transmission by activating inhibitory muscarinic M(2) receptors on motor nerve terminals.  

Science.gov (United States)

This study was undertaken to investigate the mechanism by which the toxin from the bee venom, apamin, might exert beneficial effects in patients suffering from myotonic dystrophy. The effects of apamin were compared with those produced by another potassium channel blocker, 4-aminopyridine, on rat hemidiaphragm preparations stimulated at a 100 Hz frequency via the phrenic nerve. Apamin and 4-aminopyridine increased nerve-evoked tetanic fade without changing the maximal tetanic tension. The inhibitory effect of apamin was mimicked by acetylcholine. In contrast with apamin, 4-aminopyridine increased the amplitude of muscle contractions induced by nerve stimulation at 0.2 Hz frequency. All these compounds were devoid of effect when diaphragm muscle fibres were stimulated directly in the presence of the neuromuscular blocker, D-tubocurarine. The muscarinic M(2) receptor antagonist, methoctramine, prevented the inhibitory effects of both apamin and acetylcholine. Blockade of presynaptic facilitatory muscarinic M(1) and nicotinic receptors respectively with pirenzepine and hexamethonium increased apamin-induced tetanic fade. Data suggest that apamin inhibits neuromuscular transmission by a mechanism independent of the blockade of Ca(2+)-activated K(+) channels, which might involve the activation of inhibitory muscarinic M(2) receptors on motor nerve terminals. Such a mechanism may be the origin of the beneficial effect of apamin controlling muscle excitability in patients suffering from myotonic diseases. PMID:19818752

de Matos Silva, Ledyanne Francielle Casitas; de Paula Ramos, Edivan Rodrigo; Ambiel, Celia Regina; Correia-de-Sá, Paulo; Alves-Do-Prado, Wilson

2010-01-25

110

Effects of electromyography-driven robot-aided hand training with neuromuscular electrical stimulation on hand control performance after chronic stroke.  

Science.gov (United States)

Abstract Purpose: An electromyography-driven robot system integrated with neuromuscular electrical stimulation (NMES) was developed to investigate its effectiveness on post-stroke rehabilitation. Methods: The performance of this system in assisting finger flexion/extension with different assistance combinations was evaluated in five stroke subjects. Then, a pilot study with 20-sessions training was conducted to evaluate the training's effectiveness. Results: The results showed that combined assistance from the NMES-robot could improve finger movement accuracy, encourage muscle activation of the finger muscles and suppress excessive muscular activities in the elbow joint. When assistances from both NMES and the robot were 50% of their maximum assistances, finger-tracking performance had the best results, with the lowest root mean square error, greater range of motion, higher voluntary muscle activations of the finger joints and lower muscle co-contraction in the finger and elbow joints. Upper limb function improved after the 20-session training, indicated by the increased clinical scores of Fugl-Meyer Assessment, Action Research Arm Test and Wolf Motor Function Test. Muscle co-contraction was reduced in the finger and elbow joints reflected by the Modified Ashworth Scale. Conclusions: The findings demonstrated that an electromyography-driven NMES-robot used for chronic stroke improved hand function and tracking performance. Further research is warranted to validate the method on a larger scale. Implications for Rehabilitation The hand robotics and neuromuscular electrical stimulation (NMES) techniques are still separate systems in current post-stroke hand rehabilitation. This is the first study to investigate the combined effects of the NMES and robot on hand rehabilitation. The finger tracking performance was improved with the combined assistance from the EMG-driven NMES-robot hand system. The assistance from the robot could improve the finger movement accuracy and the assistance from the NMES could reduce the muscle co-contraction on finger and elbow joints. The upper limb functions were improved on chronic stroke patients after the pilot study of 20-session hand training with the combined assistance from the EMG-driven NMES-robot. The muscle spasticity on finger and elbow joints was reduced after the training. PMID:24377757

Rong, Wei; Tong, Kai Yu; Hu, Xiao Ling; Ho, Sze Kit

2013-12-31

111

[Respiratory treatments in neuromuscular disease].  

Science.gov (United States)

In a previous article, a review was presented of the respiratory pathophysiology of the patient with neuromuscular disease, as well as their clinical evaluation and the major complications causing pulmonary deterioration. This article presents the respiratory treatments required to preserve lung function in neuromuscular disease as long as possible, as well as in special situations (respiratory infections, spinal curvature surgery, etc.). Special emphasis is made on the use of non-invasive ventilation, which is changing the natural history of many of these diseases. The increase in survival and life expectancy of these children means that they can continue their clinical care in adult units. The transition from pediatric care must be an active, timely and progressive process. It may be slightly stressful for the patient before the adaptation to this new environment, with multidisciplinary care always being maintained. PMID:24890888

Martínez Carrasco, C; Cols Roig, M; Salcedo Posadas, A; Sardon Prado, O; Asensio de la Cruz, O; Torrent Vernetta, A

2014-10-01

112

Autoimmune Neuromuscular Disorders in Childhood  

OpenAIRE

Autoimmune neuromuscular disorders in childhood include Guillain-Barré syndrome and its variants, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), juvenile myasthenia gravis (JMG), and juvenile dermatomyositis (JDM), along with other disorders rarely seen in childhood. In general, these diseases have not been studied as extensively as they have been in adults. Thus, treatment protocols for these diseases in pediatrics are often based on adult practice, but despite the simila...

Mcmillan, Hugh J.; Darras, Basil T.; Kang, Peter B.

2011-01-01

113

Effects of neuromuscular blocking agents on central respiratory chemosensitivity in newborn rats  

OpenAIRE

Neuromuscular blocking agents suppress central respiratory activity through their inhibitory effects on preinspiratory neurons and the synaptic drive from preinspiratory neurons to inspiratory neurons. Central CO2-chemosensitive areas, which partly consist of CO2-excited neurons, in the rostral ventrolateral medulla are thought to provide tonic drive to the central respiratory network and involve cholinergic mechanisms, which led us to hypothesize that neuromuscular blocking agents can inhibi...

SHIGEKI SAKURABA; SHUN-ICHI KUWANA; Eriksson, Lars I.; YASUMASA OKADA; RYOICHI OCHIAI; MASANORI KASHIWAGI; EIKI HATORI; Lindahl, Sten G. E.; JUNZO TAKEDA

2005-01-01

114

Evidence of neuroaxonal degeneration in myofascial pain syndrome: a study of neuromuscular jitter by axonal microstimulation.  

Science.gov (United States)

The mechanism of myofascial pain syndrome (MPS) is unclear. Previous reports pointed out that pathogenesis of either referred pain or local twitch response in trigger point of MPS is related to the nerve degeneration and disintegration of motor and sensory nerves in spinal cord. The purpose of the present study is to investigate the evidence of neuromuscular transmission disorders in trigger point muscles of patients with MPS by using stimulated single-fiber electromyography (SFEMG) examination. Twenty-three patients with neck MPS and 16 age-matched controls attended for the present study. The jitter or mean consecutive difference (MCD) was calculated as the mean of the absolute differences for 30 consecutive interpotential intervals between stimuli and single-fiber potentials in trapezius and levator scapulae muscles. The relationship between the MCD values and the disease duration was measured. The results showed significantly increased MCDs in trapezius and levator scapulae muscles in MPS patients. MCD values measured in the trigger point muscles were found to be positively correlated with the disease duration. The present study with axonal microstimulation and SFEMG demonstrates a prominent evidence of neuroaxonal degeneration and neuromuscular transmission disorders in the trigger point muscles of MPS patients. The mechanism of MPS is possibly implicated with the degeneration of motor neurons. PMID:18321737

Chang, Chein-Wei; Chen, Yu-Ren; Chang, Kai-Fong

2008-11-01

115

Trunk antagonist co-activation is associated with impaired neuromuscular performance  

OpenAIRE

The goal of this paper was to determine if trunk antagonist activation is associated with impaired neuromuscular performance. To test this theory, we used two methods to impair neuromuscular control: strenuous exertions and fatigue. Force variability (standard deviation of force signal) was assessed for graded isometric trunk exertions (10, 20, 40, 60, 80 % of max) in flexion and extension, and at the start and end of a trunk extensor fatiguing trial. Normalized EMG signals for five trunk mus...

Reeves, N. Peter; Cholewicki, Jacek; Milner, Theodore; Lee, Angela

2008-01-01

116

Computed tomography of muscles in neuromuscular disease  

International Nuclear Information System (INIS)

137 patients with neuromuscular diseases were studied by CT scan. Four levels were chosen: mid-calf, mid-thigh, pelvic girdle, and spinal muscles. The scans were compared with normal control scans taken from the same sites. The patients were divided into those with myogenic diseases and those with neurogenic diseases. Of the 102 patients with myogenic changes, 17 had X-linked dystrophy, 13 had facio-scapulo-humeral dystrophy, 22 had limb girdle dystrophy, 19 had myotonic dystrophy, 14 had inflammatory muscle diseases, and 17 had miscellaneous muscular diseases. Of the 35 patients with neurogenic changes, 8 had amyotrophic lateral sclerosis (ALS), 16 had chronic spinal amyotrophies, 9 had peripheral neuropathies, and 2 had Friedreich's disease. The analysis of muscles changes (volume, outline, density) was established on the following muscles: tibialis anterior, peroneus, soleus, gastrocnemius mediale, gastrocnemius laterale, quadriceps, semitendinosus, semimembranosus, sartorius, adductor, gracilis, gluteus, spine extensors, and psoas

117

Hydrauric control device for control rod drive mechanism  

International Nuclear Information System (INIS)

Purpose: To eliminate occurrence of rust at piping material by setting the temperature of scram water supplied to a control rod drive mechanism so as not to become lower than that of coolant flowing through an inserted pipe normally. Constitution: a hydraulic control device for a control rod drive mechanism consists of a scram piston mechanism provided at the joining point between the rear flow side of a check valve of a coolant feed pipe and the rear flow side of an inserted side scram valve, and a pressure equalizing pipe and a pressure equalizing solenoid valve interposed with the inserted side scram valve side and a scram piston mechanism. On the other hand, the scram piston mechanism consists of an outer cylinder, a scram piston, a spring for fixing the piston, and a coolant feed pipe, a scram pipe connected from the inserted side scram valve and an inserted pipe connected to the outer cylinder. Therefore, control rod coolant always flowing can be fed through the inserted pipe as scram water to the control rod drive mechanism. When the temperature of the control rod coolant is controlled, the temperature of the inserted pipe can be controlled to eliminate the condensation of dew. (Yoshino, Y.)

118

Alterações da junção neuromuscular em miopatias experimentais no camundongo / The neuromuscular junction in experimental myopathies in the mouse  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese As alterações morfológicas observadas em junção neuromuscular de dois modelos de miopatia em camundongos são estudadas por métodos histoquímicos para demonstrar atividade da enzima acetilcolinesterase e por microscopia eletrônica. Em ambas as situações os resultados obtidos são similares, indicando [...] que a junção neuromuscular permanece intacta mesmo quando a fibra que inerva está sofrendo necrose. Em fibras musculares regeneradas há acentuada simplificação das pregas pós-sinápticas, com redução de até 50% dos valores normais, comprovado por estudos morfométricos. A ausência de repercussões fisiológicas ou clínicas detectáveis nesses modelos, apesar da significativa hipotrofia da membrana pós-sináptica, sugere que a exuberante quantidade de pregas pós-sinápticas normalmente encontradas nas junções mioneürais pode representar mecanismo anatômico de segurança na transmissão química neuromuscular. Abstract in english Morphological abnormalities of the neuromuscular junction in two murine models with primary myopathy were studied by combined cholinesterase-silver impregnation techniques and electron microscopy. In both situations the results were similar showing that the neuromuscular junction remained unaffected [...] even when inervating necrotic muscle fibres. In regenerated muscle fibres, however, there was marked simplification of the post-synaptic membrane with reduction in number and depth of folds up to 50% of normal values confirmed by morphometric analysis. Since after regeneration succeded no detectable clinical or physiological alterations were observed in these experiments it seems reasonable to assume that the prominent branching of post-synaptic folds in normal skeletal muscles might represent an increased anatomical safety mechanism in chemical transmission.

Luiz Fernando Bleggi, Torres.

1989-06-01

119

Acetylcholinesterase Clustering at the Neuromuscular Junction Involves Perlecan and Dystroglycan  

OpenAIRE

Formation of the synaptic basal lamina at vertebrate neuromuscular junction involves the accumulation of numerous specialized extracellular matrix molecules including a specific form of acetylcholinesterase (AChE), the collagenic-tailed form. The mechanisms responsible for its localization at sites of nerve– muscle contact are not well understood. To understand synaptic AChE localization, we synthesized a fluorescent conjugate of fasciculin 2, a snake ?-neurotoxin that tightly binds to...

Peng, H. Benjamin; Xie, Hongbo; Rossi, Susanna G.; Rotundo, Richard L.

1999-01-01

120

Computed tomography of skeletal muscles in neuromuscular disease  

International Nuclear Information System (INIS)

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. (orig.)

121

Identification and Control of Mechanical Systems  

Science.gov (United States)

The control of vibrating systems is a significant issue in the design of aircraft, spacecraft, bridges, and high-rise buildings. This book discusses the control of vibrating systems, integrating structural dynamics, vibration analysis, modern control, and system identification. By integrating these subjects engineers will need only one book, rather than several texts or courses, to solve vibration control problems. The authors cover key developments in aerospace control and identification theory, including virtual passive control, observer and state-space identification, and data-based controller synthesis. They address many practical issues and applications, and show examples of how various methods are applied to real systems. Some methods show the close integration of system identification and control theory from the state-space perspective, rather than from the traditional input-output model perspective of adaptive control. This text will be useful for advanced undergraduate and beginning graduate students in aerospace, mechanical, and civil engineering, as well as for practicing engineers.

Juang, Jer-Nan; Phan, Minh Q.

2001-08-01

122

Common complications of pediatric neuromuscular disorders.  

Science.gov (United States)

Children with pediatric neuromuscular disorders experience common complications, primarily due to immobility and weakness. Musculoskeletal complications include hip dysplasia with associated hip subluxation or dislocation, neuromuscular scoliosis, and osteoporosis and resulting fractures. Constipation, gastroesophageal reflux, and obesity and malnutrition are commonly experienced gastrointestinal complications. Disordered sleep also is frequently observed, which affects both patients and caregivers. PMID:25479776

Skalsky, Andrew J; Dalal, Pritha B

2015-02-01

123

A biodynamic feedthrough model based on neuromuscular principles.  

Science.gov (United States)

A biodynamic feedthrough (BDFT) model is proposed that describes how vehicle accelerations feed through the human body, causing involuntary limb motions and so involuntary control inputs. BDFT dynamics strongly depend on limb dynamics, which can vary between persons (between-subject variability), but also within one person over time, e.g., due to the control task performed (within-subject variability). The proposed BDFT model is based on physical neuromuscular principles and is derived from an established admittance model-describing limb dynamics-which was extended to include control device dynamics and account for acceleration effects. The resulting BDFT model serves primarily the purpose of increasing the understanding of the relationship between neuromuscular admittance and biodynamic feedthrough. An added advantage of the proposed model is that its parameters can be estimated using a two-stage approach, making the parameter estimation more robust, as the procedure is largely based on the well documented procedure required for the admittance model. To estimate the parameter values of the BDFT model, data are used from an experiment in which both neuromuscular admittance and biodynamic feedthrough are measured. The quality of the BDFT model is evaluated in the frequency and time domain. Results provide strong evidence that the BDFT model and the proposed method of parameter estimation put forward in this paper allows for accurate BDFT modeling across different subjects (accounting for between-subject variability) and across control tasks (accounting for within-subject variability). PMID:24043420

Venrooij, Joost; Abbink, David A; Mulder, Mark; van Paassen, Marinus M; Mulder, Max; van der Helm, Frans C T; Bulthoff, Heinrich H

2014-07-01

124

Neuromuscular: Acetylcholine and Acetylcholine Receptors  

Science.gov (United States)

The Neuromuscular Disease Center at Washington University provides this comprehensive Web site for information on acetylcholine and acetylcholine receptors. Visitors will find detailed Web pages covering acetylcholine metabolism, acetylcholine receptors (including disorders, structure, venom binding, etc.), autonomic function, and myasthenic disorders. Related proteins are organized into data tables, which include links to protein-specific information from external sources such as the National Center for Biotechnology Information from the National Institutes of Health and the Expert Protein Analysis System (ExPASy) from the Swiss Institute of Bioinformatics.

125

Packet Loss Control Using STLCC Mechanism  

OpenAIRE

Presently the Internet accommodates simultaneous audio, video, and data traffic. This requires the Internet to guarantee the packet loss which at its turn depends very much on congestion control. A series of protocols have been introduced to supplement the insufficient TCP mechanism controlling the network congestion. CSFQ was designed as an open-loop controller to provide the fair best effort service for supervising the per-flow bandwidth consumption and has become helpless when the P2P flow...

Srikanth Reddy, G.

2013-01-01

126

Resistance training and neuromuscular performance in seniors.  

Science.gov (United States)

Age-related processes in the neuromuscular and the somatosensory system are responsible for decreases in maximal and explosive force production capacity and deficits in postural control. Thus, the objectives of this study were to investigate the effects of resistance training on strength performance and on postural control in seniors. Forty healthy seniors (67+/-1 yrs) participated in this study. Subjects were randomly assigned to a resistance training (n=20) and a control group (n=20). Resistance training for the lower extremities lasted for 13 weeks at 80% of the one repetition maximum. Pre and post tests included the measurement of maximal isometric leg extension force with special emphasis on the early part of the force-time-curve and the assessment of static (functional reach test) and dynamic (tandem walk test, platform perturbation) postural control. Resistance training resulted in an enhanced strength performance with increases in explosive force exceeding those in maximal strength. Improved performances in the functional reach and in the tandem walk test were observed. Resistance training did not have an effect on the compensation of platform perturbations. Increases in strength performance can primarily be explained by an improved neural drive of the agonist muscles. The inconsistent effect of resistance training on postural control may be explained by heterogeneity of testing methodology or by the incapability of isolated resistance training to improve postural control. PMID:19569007

Granacher, U; Gruber, M; Gollhofer, A

2009-09-01

127

Bonfils Fiberscope: Intubating Conditions and Hemodynamic Changes without Neuromuscular Blockade  

OpenAIRE

To compare intubating conditions and hemodynamic changes between Bonfils Intubation Fiberscope and Macintosh laryngoscopy without administering neuromuscular blocking drugs (NMBDs). METHODS: In this randomized controlled trial,80 male and female patients, scheduled for elective surgery, aged 15 to 60 years, ASA class II or I, non-obese, non smokers, without anticipated difficult intubation; were randomly allocated into two groups of 40: Bonfils and Macintosh. Following adequate hydration and ...

Atabak Najafi; Eiman Rahimi; Reza Shariat Moharari; Zahid Hussain Khan

2011-01-01

128

New insights into short-term synaptic facilitation at the frog neuromuscular junction.  

Science.gov (United States)

Short-term synaptic facilitation occurs during high-frequency stimulation, is known to be dependent on presynaptic calcium ions, and persists for tens of milliseconds after a presynaptic action potential. We have used the frog neuromuscular junction as a model synapse for both experimental and computer simulation studies aimed at testing various mechanistic hypotheses proposed to underlie short-term synaptic facilitation. Building off our recently reported excess-calcium-binding-site model of synaptic vesicle release at the frog neuromuscular junction (Dittrich M, Pattillo JM, King JD, Cho S, Stiles JR, Meriney SD. Biophys J 104: 2751-2763, 2013), we have investigated several mechanisms of short-term facilitation at the frog neuromuscular junction. Our studies place constraints on previously proposed facilitation mechanisms and conclude that the presence of a second class of calcium sensor proteins distinct from synaptotagmin can explain known properties of facilitation observed at the frog neuromuscular junction. We were further able to identify a novel facilitation mechanism, which relied on the persistent binding of calcium-bound synaptotagmin molecules to lipids of the presynaptic membrane. In a real physiological context, both mechanisms identified in our study (and perhaps others) may act simultaneously to cause the experimentally observed facilitation. In summary, using a combination of computer simulations and physiological recordings, we have developed a stochastic computer model of synaptic transmission at the frog neuromuscular junction, which sheds light on the facilitation mechanisms in this model synapse. PMID:25210157

Ma, Jun; Kelly, Lauren; Ingram, Justin; Price, Thomas J; Meriney, Stephen D; Dittrich, Markus

2015-01-01

129

Neuromuscular deficits following peripheral joint injury: A neurophysiological hypothesis.  

Science.gov (United States)

In addition to biomechanical disturbances, peripheral joint injuries (PJI) can also result in chronic neuromuscular alterations due in part to loss of mechanoreceptor-mediated afferent feedback. An emerging perspective is that PJI should be viewed as a neurophysiological dysfunction, not simply a local injury. Neurophysiological and neuroimaging studies have provided some evidence for central nervous system (CNS) reorganization at both cortical and spinal levels following peripheral joint injuries. The novel hypothesis proposed is that CNS reorganization is the underlying mechanism for persisting neuromuscular deficits following injury, in particular, muscle weakness. There is a lack of direct evidence to support this hypothesis, but future studies utilizing force-matching tasks with superimposed transcranial magnetic stimulation may be a step forward in clarifying this notion. © 2014 Wiley Periodicals, Inc. PMID:25255714

Ward, Sarah; Pearce, Alan J; Pietrosimone, Brian; Bennell, Kim; Clark, Ross; Bryant, Adam L

2014-09-26

130

Early appearance and possible roles of non-neuromuscular cholinesterases.  

Directory of Open Access Journals (Sweden)

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.

CarlaFalugi

2012-04-01

131

Control rod drive mechanism vent valve assembly  

International Nuclear Information System (INIS)

The invention relates generally to a device for closing a tubular object and more particularly to a device having venting means incorporated therein and used for closing a control rod drive mechanism which is installed on a nuclear reactor. A ball valve that is capable of performing the necessary function is described

132

Mechanical components design for PWR - control rod drive mechanism  

International Nuclear Information System (INIS)

The Control Rod Drive Mechanism (CRDM) is usually - a high precision - equipment incorporating mechanical and electrical components designed to move the control rods. The 'control rods' refer to all rods or assemblies that are moved to assess the performance of the reactor. The CRDM here presented is the Nut and Lead Screw type. This type is basically a power screw type magnetically coupled to a slow speed reluctance electric motor that provides a means of axially positioning the movable fuel assemblies in the reactor core for purpose of controlling core reactivity. A helically threaded lead screw assembly, comprising one element of power screw, is attached to a movable fuel assemblies. The CRDM usually has closer and more consistent contact with environment peculiar to the reactor than has only other machinery component. This environment includes not only the radiation field of the reactor, but also the temperature, pressure and chemical properties associated with the material used as the coolant for reactor fuel. Specific and special materials are needed because of the above mentioned application. Due to the importance of the above described CRDM functions, this paper will also consider the nuclear functions and their safety classes as well as the CRDM nuclear design criteria. (author)

133

La monitorización neuromuscular y su importancia en el uso de los bloqueantes neuromusculares / Neuromuscular monitoring and its importance in neuromuscular blockade  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Introducción: La necesidad por incorporar nuevas guías o estrategias en la buena práctica de uso de los bloqueantes neuromusculares no es un hecho de obligado cumplimento en la actualidad dentro de la anestesiología. Solo existen recomendaciones de actuación con el propósito de convencer que la moni [...] torización neuromuscular es una herramienta muy útil para el buen uso racional de los bloqueantes neuromusculares. Metodología: Las complicaciones surgen, y la parálisis residual es un evento destacado. Por esta razón, los autores propugnamos que la monitorización del bloqueo neuromuscular puede ser un factor determinante en la mejora del cuidado de nuestros pacientes, disminuyendo tanto la morbilidad como la mortalidad. Esta revisión y su metodología en base a la experiencia de los autores solo pretende exponer de forma sencilla conocimientos que consideramos básicos para su utilización sistemática en nuestra práctica rutinaria. Resultados y conclusiones: Esta actualización describe los principios fundamentales de los métodos que disponemos en la actualidad, priorizando las medidas cuantitativas de registro. Y también demuestra el diferente comportamiento de la musculatura al efecto de los bloqueantes neuromusculares, fundamentos relevantes que es preciso conocer. La monitorización neuromuscular es una práctica que debe utilizarse siempre que un bloqueo neuromuscular sea necesario. Somos conscientes que generar una recomendación explícita es difícil. Pero nuestro entusiasmo parte del beneficio de una experiencia personal con estos métodos que son conocidos desde antiguo. Debido a la potencial morbilidad asociada con bloqueos neuromusculares residuales, la monitorización perioperatoria de la función neuromuscular es esencial. Abstract in english Introduction: The incorporation of new guidelines or strategies as part of good practices in the use of muscle relaxants is not a requirement at present in the practice of anesthesia. There are only action recommendations designed to persuade clinicians of the fact that neuromuscular monitoring is a [...] very useful tool for the rational use of muscle relaxants. Methodology:Complications occur, and residual paralysis is a significant event. For this reason, the authors advocate that monitoring neuromuscular block may be a determining factor in improving patient care and reducing morbidity and mortality. This review and its methodology based on the experience of the authors is designed to present, in a simple format, the knowledge that considered fundamental for the systematic use of neuromuscular monitoring in every day practice. Results and conclusions: This update describes the fundamental principles of the methods available at present, emphasizing quantitative recording measurements. It then describes the different ways in which muscles respond to the effect of neuromuscular blockade, as these are critical fundamental principles that have to be known. Neuromuscular monitoring is a practice that should be implemented every time a neuromuscular block is required. We are aware of the difficulty of generating an explicit recommendation, but our enthusiasm is derived from the benefits we have personally experienced when applying these methods that have been known for a long time. Due to the potential morbidity associated with residual muscle relaxation, perioperative monitoring of neuromuscular function is essential.

Joaquín, Fabregat López; César Augusto, Candia Arana; Caridad Greta, Castillo Monzón.

2012-12-01

134

Adiposity is associated with improved neuromuscular reaction time.  

Science.gov (United States)

Many studies have focused on the detrimental effects of malnourishment to the performance of the brain and peripheral nerves. Undernourished children and adults have been studied extensively to establish these consequences. Little attention has been given to the body habitus that affects optimum neurological performance and the implications for individuals on the spectral extremes of the healthy weight range. This paper examines the association between markers of adiposity and neurological performance, inclusive of all body types. The data were obtained from Cape Coloured youths (5-20 years) in South Africa from the rural district of Klein Karoo and the urban population of Cape Town. In all, the sums of skin-folds were measured for almost 4000 students. The neuromuscular reaction time was also calculated using a ruler drop test. This measure may serve as a gross marker of peripheral and central neurological performance as both are needed to execute the reflex command. There was a direct correlation between adiposity and neuromuscular reaction time. Whilst controlling for age, increasing fatness was associated with a decrease in neuromuscular reaction time amongst both sexes. This relationship remained statistically significant, even when removing the thinnest 40% of participants, eliminating the scope of influence exerted by malnourishment on the correlation. The trend appears to be more prominent amongst boys. These findings indicate that body lipid reserves are integral to the development of the nervous system even amongst children within the healthy weight ranges. Our hypothesis is that the myelination of the nerves, both centrally through oligodendrocytes and peripherally by Schwann cells, is integral to this process as they are predominantly lipid. Amongst thin but not clinically undernourished individuals, the somatic lipid reserves are modest. These fats may be minimally sequestered away for the development of myelin nerve sheath at the expense of saltatory conduction. This may account for the slowed neuromuscular reaction time demonstrated. PMID:25194500

Grantham, James; Henneberg, Maciej

2014-11-01

135

Hazard factors of ACL rupture: Neuromuscular factors  

OpenAIRE

Injuries to the anterior cruciate ligament (ACL) of the knee are disabling, often associated with other intra-articular damages and increase the risk of early onset of osteoarthritis. It is very probable that multiple risk factors act in combination to influence injury risk. It is important to have a comprehensive understanding of these ACL risk factors, whose neuromuscular factors, even if investigations on neuromuscular factors reported to date do not provide a complete understanding of ACL...

Kaux, Jean-franc?ois; Delvaux, Franc?ois; Massart, Nicolas; Daniel, Christophe; Forthomme, Be?ne?dicte; Crielaard, Jean-michel; Croisier, Jean-louis

2013-01-01

136

Sugammadex: A revolutionary drug in neuromuscular pharmacology  

Science.gov (United States)

Sugammadex (ORG 25969) is a unique neuromuscular reversal drug; a novel cyclodextrin, the first in a new class of selective relaxant binding agents, which reverse neuromuscular blockade (NMB) with the aminosteroid non-depolarizing muscle relaxants rocuronium and vecuronium. Sugammadex can reverse moderate or deep NMB. The clinical use of sugammadex promises to eliminate many of the shortcomings in current anesthetic practice with regard to antagonism of rocuronium and other aminosteroid muscle relaxants.

Nag, Kusha; Singh, Dewan Roshan; Shetti, Akshaya N.; Kumar, Hemanth; Sivashanmugam, T.; Parthasarathy, S.

2013-01-01

137

Immunology of disorders of neuromuscular transmission.  

OpenAIRE

The neuromuscular junction (NMJ) is a prototype synapse and myasthenia gravis is the prototypic antibody-mediated disorder. There are now three other disorders of neuromuscular transmission caused by antibodies to other essential components of the NMJ. Antibodies to the muscle-specific kinase, MuSK, are defining a new form of myasthenia that can be associated with muscle atrophy. Antibodies to voltage-gated calcium channels are responsible for muscle weakness and autonomic dysfunction in the ...

Vincent, A.

2006-01-01

138

Neuromuscular Effects of Acute Organophosphate Poisoning  

OpenAIRE

Purpose: The knowledge about neuromuscular effects of organophosphate poisoning depends on limited publications and case reports. In this study, we aimed to determine the neuromuscular effects of organophosphate poisoning and the influence of these information in clinical approach and treatment modalities that will guide further studies to prement disability. Materials and Methods: In this prospective study conducted for 2 years with the approval of ethical comittee, 20 patients older th...

Taylan Pekoz; Mehmet Yuzugullu; Zeynep Kekec; Filiz Koc

2014-01-01

139

PICU EXTUBATION FAILURE: THE ROLE OF NEUROMUSCULAR DISORDERS  

Directory of Open Access Journals (Sweden)

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 process needs to be done gradually in these patients, and in conjunction with supportive measures, such as close observation for at least for 72 hours following extubation to monitor any possibility of recurrence of hypercapnic respiratory failure.

N. Billan MD,

2007-02-01

140

Electrochemical biofilm control: mechanism of action  

OpenAIRE

Although it has been previously demonstrated that an electrical current can be used to control biofilm growth on metal surfaces, the literature results are conflicting and there is no accepted mechanism of action. One of the suggested mechanisms is the production of hydrogen peroxide (H2O2) on metal surfaces. However, there are literature studies in which H2O2 could not be detected in the bulk solution. This is most likely because H2O2 was produced at a low concentration near the surface and ...

Istanbullu, Ozlem; Babauta, Jerome; Nguyen, Hung Duc; Beyenal, Haluk

2012-01-01

141

Helicopter Pitch-Control Mechanism Reduces Vibration  

Science.gov (United States)

Large forces accommodated without increasing weight of helicopter structure. New mechanism yields stiffer control and improves accuracy of pitch changes under load. As result, heavy casting not for gearbox, nor extra reinforcing members needed for fuselage bulkheads, stringers, skin, and other parts. In new mechanism, reaction forces developed in rotor hub. Long load paths to gearbox and fuselage elminated. Reaction member rigidly attached to hub and rotates with it. At lower end of reaction member, bearing forms bridge to fuselage through stationary beam and antirotation link. Beam connected to reaction plate through rods.

Lemont, H.

1986-01-01

142

Packet Loss Control Using STLCC Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available Presently the Internet accommodates simultaneous audio, video, and data traffic. This requires the Internet to guarantee the packet loss which at its turn depends very much on congestion control. A series of protocols have been introduced to supplement the insufficient TCP mechanism controlling the network congestion. CSFQ was designed as an open-loop controller to provide the fair best effort service for supervising the per-flow bandwidth consumption and has become helpless when the P2P flows started to dominate the traffic of the Internet. Token-Based Congestion Control (TBCC is based on a closed-loop congestion control principle, which restricts token resources consumed by an end-user and provides the fair best effort service. As Self-Verifying CSFQ and Re-feedback, it experiences a heavy load by policing inter domain traffic for lack of trust.In this paper, Stable Token-Limited Congestion Control (STLCC is introduced as new protocols which appends interdomain congestion control to TBCC and make the congestion control system to be stable. STLCC is able to shape output and input traffic at the inter-domain link.STLCC produces a congestion index pushes the packet loss to the network edge and improves the network performance. Finally, the simple version of STLCC is introduced. This version is deployable in the Internet without any IP protocols modifications and preserves also the packet datagram.

G. Srikanth Reddy

2013-09-01

143

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

Directory of Open Access Journals (Sweden)

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.

Curtis S. To, PhD

2011-08-01

144

Cotrel-Dubousset instrumentation in neuromuscular scoliosis.  

Science.gov (United States)

The study design is retrospective. The aim is to describe our experience about the treatment of patients with neuromuscular scoliosis (NMS) using Cotrel-Dubousset instrumentation. Neuromuscular scoliosis are difficult deformities to treat. A careful assessment and an understanding of the primary disease and its prognosis are essential for planning treatment which is aimed at maximizing function. These patients may have pelvic obliquity, dislocation of the hip, limited balance or ability to sit, back pain, and, in some cases, a serious decrease in pulmonary function. Spinal deformity is difficult to control with a brace, and it may progress even after skeletal maturity has been reached. Surgery is the main stay of treatment for selected patients. The goals of surgery are to correct the deformity producing a balanced spine with a level pelvis and a solid spinal fusion to prevent or delay secondary respiratory complications. The instrumented spinal fusion (ISF) with second-generation instrumentation (e.g., Luque-Galveston and unit rod constructs), are until 1990s considered the gold standard surgical technique for neuromuscular scoliosis (NMS). Still in 2008 Tsirikos et al. said that "the Unit rod instrumentation is a common standard technique and the primary instrumentation system for the treatment of pediatric patients with cerebral palsy and neuromuscular scoliosis because it is simple to use, it is considerably less expensive than most other systems, and can achieve good deformity correction with a low loss of correction, as well as a low prevalence of associated complications and a low reoperation rate." In spite of the Cotrel-Dubousset (CD) surgical technique, used since the beginning of the mid 1980s, being already considered the highest level achieved in correction of scoliosis by a posterior approach, Teli et al., in 2006, said that reports are lacking on the results of third-generation instrumentation for the treatment of NMS. Patients with neuromuscular disease and spinal deformity treated between 1984 and 2008 consecutively by the senior author (G.D.G.) with Cotrel-Dubousset instrumentation and minimum 36 months follow-up were reviewed, evaluating correction of coronal deformity, sagittal balance and pelvic obliquity, and rate of complications. 24 patients (Friedreich's ataxia, 1; cerebral palsy, 14; muscular dystrophy, 2; polio, 2; syringomyelia, 3; spinal atrophy, 2) were included. According the evidence that the study period is too long (1984-2008) and that in more than 20 years many things changed in surgical strategy and techniques, all patients were divided in two groups: only hooks (8 patients) or hybrid construct (16 patients). Mean age was 18.1 years at surgery (range 11 years 7 months-max 31 years; in 17 cases the age at surgery time was between 10 and 20 years old; in 6 cases it was between 20 and 30 and only in 1 case was over 30 years old). Mean follow-up was 142 months (range 36-279). The most frequent patterns of scoliosis were thoracic (10 cases) and thoracolumbar (9 cases). In 8 cases we had hypokyphosis, in 6 normal kyphosis and in 9 hyperkyphosis. In 8 cases we had a normal lordosis, in 11 a hypolordosis and in 4 a hyperlordosis. In 1 case we had global T4-L4 kyphosis. In 8 cases there were also a thoracolumbar kyphosis (mean value 24°, min 20°-max 35°). The mean fusion area included 13 vertebrae (range 6-19); in 17 cases the upper end vertebra was over T4 and in 11 cases the lower end vertebra was over L4 or L5. In 7 cases the lower end vertebra was S1 to correct the pelvic obliquity. In 5 cases the severity of the deformity (mean Cobb's angle 84.2°) imposed a preoperative halo traction treatment. There were 5 anteroposterior and 19 posterior-only procedures. In 10 cases, with low bone quality, the arthrodesis was performed using iliac grafting technique while in the other (14 cases) using autologous bone graft obtained in situ from vertebral arches and spinous processes (in all 7 cases with fusion extended until S1, it was augmented with calcium phosphate). The mean correction

Piazzolla, Andrea; Solarino, G; De Giorgi, S; Mori, C M; Moretti, L; De Giorgi, G

2011-05-01

145

Papel da vitamina D na função neuro-muscular Role of vitamin D in the neuro-muscular function  

Directory of Open Access Journals (Sweden)

Full Text Available A vitamina D, através de suas ações no intestino, rim, osso e glândulas paratiróides, é um hormônio fundamental para a homeostase do cálcio e para o desenvolvimento de um esqueleto saudável. Além disso, receptores deste hormônio podem ser encontrados em quase todos os tecidos do organismo e outras ações não relacionadas ao metabolismo mineral têm sido imputadas a ele. Na célula muscular esquelética, a vitamina D atua através do mecanismo clássico de ligação a um receptor nuclear e também através da ligação a um receptor de membrana, realizando ações que envolvem o transporte de cálcio, a síntese protéica e a velocidade de contração muscular. Clinicamente, a deficiência de vitamina D, que é bastante comum em idosos, inclusive em nosso país, tem sido relacionada a um aumento da incidência de quedas, a uma diminuição da força muscular e a uma deterioração do equilíbrio, avaliada pela oscilação do corpo na postura ereta. Por outro lado, tem sido demonstrado que a suplementação associada de cálcio e vitamina D em idosos deficientes contribui para melhoria destes aspectos da função neuro-muscular. Nesta revisão, serão discutidos os mecanismos conhecidos envolvidos na associação entre vitamina D e função neuro-muscular, e também a suplementação de vitamina D e cálcio na prevenção de fraturas osteoporóticas não-vertebrais sob a perspectiva dos efeitos neuro-musculares.Through its action in the kidney, intestines, bone and parathyroid glands vitamin D is a major regulator of calcium homeostasis and for the development of a healthy skeleton. Moreover, receptors for this hormone are present in almost all body tissues and other actions which are not related to the mineral metabolism have been imputed to it. In the skeletal muscle cell, vitamin D acts through the classic mechanism of binding to a nuclear receptor and also by binding to a membrane receptor, carrying out actions that involve calcium transport, protein synthesis and kinetics of muscle contraction. Clinically, vitamin D deficiency, which is very common among the elderly, including the ones in our country, has been related to an increase in the incidence of falls, as well as the reduction of muscle strength and deterioration of body sway, evaluated by the oscillation of the body in the erect position. On the other hand, it has been demonstrated that supplementation of calcium associated to vitamin D in deficient elderly contributes to the improvement of these aspects of the neuro-muscular function. In this review, the mechanisms involved in the association between vitamin D and neuro-muscular function will be discussed, as well as the supplementation of vitamin D and calcium to prevent non-vertebral osteoporotic fractures under the perspective of the neuro-muscular effects.

Márcia A. Carneiro Pedrosa

2005-08-01

146

Control rod drive mechanisms seismic analysis  

International Nuclear Information System (INIS)

In the Taishan joint-design, in order to finish Control Rod Drive Mechanism (CRDM) seismic analysis, a response spectrum analysis in combination with quasi-static analysis and a time history analysis are performed according to the different design stages and inputs. The simulated and simplified model of nonlinear structure is studied in the basic design stage; the translation of seismic input data and the use of nonlinear elements are studied in the detailed design stage. (authors)

147

Integrating Conflict Detection and Attentional Control Mechanisms  

OpenAIRE

Human behavior involves monitoring and adjusting performance to meet established goals. Performance-monitoring systems that act by detecting conflict in stimulus and response processing have been hypothesized to influence cortical control systems to adjust and improve performance. Here we used fMRI to investigate the neural mechanisms of conflict monitoring and resolution during voluntary spatial attention. We tested the hypothesis that the ACC would be sensitive to conflict during attentiona...

Walsh, Bong J.; Buonocore, Michael H.; Carter, Cameron S.; Mangun, George R.

2010-01-01

148

Clinical applications of immunoglobulin in neuromuscular diseases: focus on inflammatory myopathies / Aplicações clínicas de imunoglobulina em doenças neuromusculares com foco em miopatias inflamatórias  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Nos últimos anos, um número progressivo de doenças neuromusculares passaram a ser reconhecidas tanto por ser causadas por mecanismos autoimunes ou por envolver importantes componentes autoimunes. Os mecanismos fisiopatológicos e as manifestações clínicas envolvidos têm sido mais bem reconhecidos e m [...] uitas de tais doenças são potencialmente tratáveis por imunossupressão ou imunomodulação com imunoglobulina intravenosa (IVIg). IVIg vem sendo utilizada em uma variedade de doenças neurológicas imunomediadas, sendo alvo de amplo uso em doenças dos sistemas nervosos central e periférico. Objetivo Oferecer uma visão global sobre os principais tópicos relacionados aos mecanismos de ação e aos diferentes usos terapêuticos da IVIg na prática neurológica, principalmente em doenças neuromusculares. Abstract in english 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.

Paulo Victor Sgobbi de, Souza; Wladimir Bocca Vieira de Rezende, Pinto; Acary Souza Bulle, Oliveira.

2014-12-01

149

Adhesion in vascular biology: Mechanics control dynamics.  

Science.gov (United States)

The vasculature delivers vital support for all other tissues by supplying oxygen and nutrients for growth and by transporting the immune cells that protect and cure them. Therefore, the microvasculature developed a special barrier that is permissive for gasses like oxygen and carbon dioxide, while fluids are kept inside and pathogens are kept out. While maintaining this tight barrier, the vascular wall also allows immune cells to exit at sites of inflammation or damage, a process that is called transmigration. The endothelial cell layer that forms the inner lining of the vasculature is crucial for the vascular barrier function as well as the regulation of transmigration. Therefore, adhesions between vascular endothelial cells are both tight and dynamic and the mechanisms by which they are established, and the mechanisms by which they are controlled have been extensively studied over the past decades. Because of our fundamental strive to understand biology, but also because defects in vascular barrier control cause a variety of clinical problems and treatment strategies may evolve from our detailed understanding of its mechanisms. This special focus issue features a collection of articles that review key components of the development and control of the endothelial cell-cell junction that is central to endothelial barrier function. PMID:24828485

de Rooij, Johan

2014-05-14

150

Frecuencia de anticuerpos contra neospora caninum y toxoplasma gondii en canes con signos clínicos de afección neuromuscular / Frequency of antibodies against neospora caninum y toxoplasma gondii in dogs with clinical signs of neuromuscular disease  

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: Spanish Abstract in spanish Toxoplasma gondii y Neospora caninum son causantes de enfermedades neuromusculares en canes. El objetivo de este estudio de Caso-Control fue encontrar la asociación entre la presencia de anticuerpos contra N. caninum y T. gondii en canes con signos clínicos neuromusculares. Se colectó muestras de sa [...] ngre a 96 y 120 canes con y sin signos clínicos de afección neuromuscular, respectivamente. Los sueros se analizaron con la prueba de Inmunofluorescencia Indirecta (IFI) para la detección de anticuerpos (IgG), donde los sueros con fluorescencia completa del taquizoíto en la dilución 1:50 fueron considerados positivos. La frecuencia para T. gondii fue de 24.0 ± 8.5% (23/96) y de 3.3 ± 3.1 (4/120) para canes con y sin afecciones neuromusculares, respectivamente, y para N. caninum fue de 5.2 ± 4.4 (5/96) y de 1.7 ± 2.5 (2/120) para canes con y sin afecciones neuromusculares, respectivamente. Se observó asociación significativa entre la afección neuromuscular y la presencia de anticuerpos anti-T. gondii, mas no así con anticuerpos anti-N. caninum. Abstract in english Toxoplasma gondii and Neospora caninum can cause neuromuscular disorders in dogs. The aim of the Case-Control study was to determine the association between antibodies anti N. caninum and anti-T. gondii in dogs with neuromuscular disorders. Blood samples were collected in 96 and 120 dogs with and wi [...] thout clinical signs of neuromuscular disorders respectively. Serum samples were analyzed by the indirect immunofluorescence test (IFI) for the detection of IgG antibodies, considering positive the sera showing complete fluorescence of the tachyzoite in the dilution 1:50. The frequency for T. gondii was 24.0 ± 8.5% (23/96) and 3.3 ± 3.1 (4/120) for dogs with and without signs of neuromuscular disorders, and for N. caninum was 5.2 ± 4.4 (5/96) and 1.7 ± 2.5 (2/120) for dogs with and without signs of neuromuscular disorders, respectively. There was a significant association between neuromuscular disorders and the presence of anti-T. gondii antibodies but not in the case of the presence of anti-N. caninum antibodies.

Nelson, Ruíz R; Eva, Casas A; Francisco, Suárez A; Diego, Díaz C; Viviana, Fernández P.

2012-12-01

151

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

Directory of Open Access Journals (Sweden)

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.

de Araújo Carlos José Soares

2012-11-01

152

Neuromuscular Adaptations to Reduced Use  

Science.gov (United States)

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.

Ploutz-Snyder, Lori

2009-01-01

153

Functional Neuromuscular Stimulation Controlled by Surface Electromyographic Signals Produced by Volitional Activation of the Same Muscle : Adaptive Removal of the Muscle Response from the Recorded EMG-Signal  

OpenAIRE

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, therefor...

Sennels, Søren; Biering-sørensen, Fin; Andersen, Ole Trier; Hansen, Steffen Duus

2006-01-01

154

Bonfils Fiberscope: Intubating Conditions and Hemodynamic Changes without Neuromuscular Blockade  

Directory of Open Access Journals (Sweden)

Full Text Available To compare intubating conditions and hemodynamic changes between Bonfils Intubation Fiberscope and Macintosh laryngoscopy without administering neuromuscular blocking drugs (NMBDs. METHODS: In this randomized controlled trial,80 male and female patients, scheduled for elective surgery, aged 15 to 60 years, ASA class II or I, non-obese, non smokers, without anticipated difficult intubation; were randomly allocated into two groups of 40: Bonfils and Macintosh. Following adequate hydration and preoxygenation, midazolam 0.03 mg.kg-1 was administered, followed by intravenous alfentanil 20 µg.kg-1, lidocaine 1.0 mg.kg-1, and propofol 2 mg.kg-1 sequentially. Trachea was then intubated using Bonfils Intubation Fiberscope in the Bonfils group and conventional Macintosh laryngoscopy in the Macintosh group. Intubating condition, mean arterial blood pressure, heart rate, pulse oximetry, and success rate were measured. RESULTS: Clinically acceptable intubating condition scores did not differ significantly between the groups (P=0.465. Compared to the baseline values, heart rate rose significantly after intubation only in the Macintosh group (P<0.001. Although mean arterial blood pressure increased immediately after intubation in the Macintosh group (P=0.022, its post-intubation values were significantly less than baseline in both groups (P<0.001. Intubation time took much longer in the Bonfils group (40 s than the Macintosh group (11 s, P<0.001. In the absence of NMBDs, Bonfils Intubation Fiberscope compares well with Macintosh laryngoscopy in terms of success rate and intubating conditions, but with less mechanical stress and hemodynamic compromise and longer intubation time.

Atabak Najafi

2011-04-01

155

Functional Neuromuscular Stimulation Controlled by Surface Electromyographic Signals Produced by Volitional Activation of the Same Muscle : Adaptive Removal of the Muscle Response from the Recorded EMG-Signal  

DEFF Research Database (Denmark)

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 tested on both simulated and real data. The filter performance is compared with a conventional fixed comb filter. The simulations indicate that the adaptive filter is relatively insensitive to variations in amplitude of the muscle responses, and for all filter lengths produces a good filtering. For variations in shape of the muscle responses and for real data, an increased filter performance can be achieved by increasing the filter length. Using a filter length of up to seven stimulation periods, it is possible to reduce real muscle responses to a level comparable with the background noise. Using 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 of the same muscle

Sennels, SØren; Biering-SØrensen, Fin

1997-01-01

156

Maintenance of BWR control rod drive mechanisms  

International Nuclear Information System (INIS)

Control rod drive mechanism (CRDM) replacement and rebuilding is one of the highest dose, most physically demanding, and complicated maintenance activities routinely accomplished by BWR utilities. A recent industry workshop sponsored by the Oak Ridge National Laboratory, which dealt with the effects of CRDM aging, revealed enhancements in maintenance techniques and tooling which have reduced ALARA, improved worker comfort and productivity, and have provided revised guidelines for CRDM changeout selection. Highlights of this workshop and ongoing research on CRDM aging are presented in this paper

157

Passive cooling of control rod drive mechanisms  

International Nuclear Information System (INIS)

A method and apparatus are provided for passively cooling the control rod drive mechanisms (CRDMs) in the reactor vessel of a nuclear power plant. Passive cooling is achieved by dispersing a plurality of chimneys within the CRDM array in positions where a control rod is not required. The chimneys induce convective air currents which cause ambient air from within the containment to flow over the CRDM coils. The air heated by the coils is guided into inlets in the chimneys by baffles. The chimney is insulated and extends through the seismic support platform and missile shield disposed above the closure head. A collar of adjustable height mates with plate elements formed at the distal end of the CRDM pressure housings by an interlocking arrangement so that the seismic support platform provides lateral restraint for the chimneys. (Author)

158

Pneumatic, PLC Controlled, Automotive Gear Shifting Mechanism  

Directory of Open Access Journals (Sweden)

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.

Muntaser Momani

2010-05-01

159

Development of Mechanical Water Level Controller  

Directory of Open Access Journals (Sweden)

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.

Akonyi Nasiru Sule

2012-10-01

160

Gain control mechanisms in spinal motoneurons  

Directory of Open Access Journals (Sweden)

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.

Michael David Johnson

2014-07-01

161

Trunk control during standing reach: A dynamical system analysis of movement strategies in patients with mechanical low back pain.  

Science.gov (United States)

The purpose of this study was to quantify lumbo-pelvic control differences between patients with mechanical low back pain (MLBP) and asymptomatic controls using a dynamical systems approach to data reduction and interpretation. Subjects were 30 patients with chronic MLBP (age: 41.1+/-8.9 years, body mass index: 26.2+/-5.2 kg/m(2)) and 35 asymptomatic controls (age: 38.8+/-9.2 years, body mass index: 25.3+/-4.8 kg/m(2)). Kinematic data were collected from the femur, pelvis and lumbar spine during repeated trials of bilateral forward reaching under two loading conditions. Sagittal plane angular motion was filtered and time normalized. Continuous relative phases were then calculated for each data point. Mean absolute relative phase (MARP) and deviation phase (DP) parameters were derived to quantify intersegmental coordination and pattern variability. Mixed-model ANOVAs revealed that lumbo-pelvic coordination was more separated in time and more variable in the chronic MLBP group during this task. Trunk neuromuscular control was thus altered in our MLBP group. Unresolved extensor muscle dysfunction is suggested by (a) preliminary analysis of phase plane trajectories, (b) subjects' greater difficulty controlling aspects of the task that required the extensors to contribute to trunk stability and primary movement control. PMID:19046882

Silfies, Sheri P; Bhattacharya, Anand; Biely, Scott; Smith, Sue S; Giszter, Simon

2009-04-01

162

Drugs to facilitate recovery of neuromuscular blockade and muscle strength.  

Science.gov (United States)

Several drugs that quicken recovery from neuromuscular blockade caused by vecuronium in anesthetized patients are reviewed. Ulinastatin, a protease inhibitor, is thought to promote the release of acetylcholine at the neuromuscular junction and increases hepatic blood flow and urine volume. For this reason, ulinastatin quickens recovery from neuromuscular blockade in anesthetized patients receiving vecuronium. Additionally, pretreatment with ulinastatin avoids prolongation of vecuronium-induced neuromuscular blockade in patients with hepatic cirrhosis. Gabexate mesilate is also a protease inhibitor. During a continuous infusion of gabexate mesilate, recovery from neuromuscular blockade was quickened. Amino acid-enriched solution supplies energy to the skeletal muscles and causes an increase in muscle strength. An infusion of amino acid-enriched solution hastens recovery from neuromuscular blockade in anesthetized patients. When amino acids supply energy to the skeletal muscles, they simultaneously produce heat in the skeletal muscles. This thermal generation may be closely related to fast recovery from neuromuscular blockade. Amino acid-enriched solution makes recovery from neuromuscular blockade quick and avoids hypothermia during general anesthesia. Milrinone, a phosphodiesterase III inhibitor, is supposed to increase the release of acetylcholine at the neuromuscular junction and make the neuromuscular junction sensitive to acetylcholine. Therefore, recovery from neuromuscular blockade is hastened. Nicorandil enhances membrane K+ conductance in skeletal muscle and increases contraction of the skeletal muscle. Thus, nicorandil quickens recovery from neuromuscular blockade. PMID:16261467

Saitoh, Yuhji

2005-01-01

163

Efeitos do aquecimento e do alongamento na resposta neuromuscular dos isquiotibiais / Effects of warm-up and stretching on the neuromuscular response of the hamstrings / Efectos del calentamiento y del alongamiento en la respuesta neuromuscular de los isquiotibiales  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese INTRODUÇÃO: A preparação para a atividade esportiva frequentemente envolve aquecimento e/ou alongamento, no intuito de prevenir lesões e/ou melhorar o desempenho. No entanto, a maneira como essas práticas podem interferir nos mecanismos neuromusculares de controle articular não é clara. OBJETIV [...] O: Analisar o efeito imediato do alongamento e do aquecimento, isolados ou associados, no tempo de latência muscular (TLM) e na amplitude de ativação dos isquiotibiais, após perturbações repentinas da articulação do joelho. MÉTODOS: Sessenta voluntários do sexo feminino (média de idade de 22,3 ± 1,7 anos e IMC 21,4 ± 1,3 kg/cm2) foram divididas aleatoriamente em quatro grupos: (1) controle, (2) aquecimento, (3) alongamento, (4) aquecimento + alongamento. A atividade elétrica dos isquiotibiais foi captada por eletromiografia de superfície durante uma perturbação súbita do joelho. Um eletrogoniômetro detectou o início da variação angular, enquanto os eletrodos captaram o início e a amplitude da atividade muscular antes e após as intervenções. Como procedimento estatístico utilizou-se ANOVA two-way e post-hoc de Tukey, considerando-se como nível de significância p Abstract in spanish INTRODUCCIÓN: La preparación para la actividad deportiva frecuentemente vincula calentamiento y/o alongamiento, con la intención de prevenir lesiones y/o mejorar el desempeño. Mientras tanto, la manera en cómo esas prácticas pueden interferir en los mecanismos neuromusculares de control articular [...] no es clara. OBJETIVO: Analizar el efecto inmediato del alongamiento y del calentamiento, aislados o asociados, en el tiempo delatencia muscular (TLM) y en la amplitud de activación de los isquiotibiales, después de perturbaciones repentinas de la articulación de la rodilla. MÉTODOS: Sesenta voluntarias del sexo femenino (promedio de edad de 22,3 ± 1,7 años e IMC 21,4 ± 1,3 kg/cm2) fueron divididas aleatoriamente en cuatro grupos: (1) control, (2) calentamiento, (3) alongamiento, (4) calentamiento + alongamiento. La actividad eléctrica de los isquiotibiales fue captada por electromiografía de superficie durante una perturbación súbita de la rodilla. Un electrogoniómetro detectó el inicio de la variación angular, mientras que los electrodos captaron el inicio y la amplitud de la actividad muscular antes y después de las intervenciones. Como procedimiento estadístico se usó ANOVA two-way y post-hoc de Tukey, considerándose como nivel de significancia p Abstract in english INTRODUCTION: The preparation for sports activities often involves warm-up and/or stretching in order to prevent injuries and/or improve performance. However, how these practices may interfere with neuromuscular mechanisms of joint control is unclear. OBJECTIVE: To analyze the immediate effect [...] of stretching and warm-up exercises, alone or combined, on muscle latency time (MLT) and hamstrings activation amplitude after sudden knee joint disturbances. METHODS: Sixty female volunteers (mean age 22.3±1.7 years, BMI 21.4±1.3kg/cm2) were randomly divided into four groups: (1) control, (2) warm-up, (3) stretching, (4) warm-up + stretching. Hamstrings electrical activity was recorded by surface electromyography during a sudden knee disturbance. An electrogoniometer detected the onset of angular variation, while electrodes recorded the onset and amplitude of muscle activity before and after interventions. Two-way ANOVA and post hoc Tukey were used in statistical analysis, considering a significance level of p

João Felipe de Souza, Nogueira; Caio Alano de Almeida, Lins; Angelica Vieira Cavalcanti, Souza; Jamilson Simões, Brasileiro.

2014-07-01

164

Research highlights of partial neuromuscular disorders  

Directory of Open Access Journals (Sweden)

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 ? (GSD ?, 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

Cheng ZHANG

2014-05-01

165

Control mechanisms for a nonlinear model of international relations  

Energy Technology Data Exchange (ETDEWEB)

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.

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

166

Poisson Theory and Inverse Problem in a Controllable Mechanical System  

International Nuclear Information System (INIS)

The Poisson theory and inverse problem are studied in a controllable mechanical system. Equations of motion of the controllable mechanical system in phase space are given. Poisson's integral theory of the system is established. The potential force field is constructed by solving the inverse problem in a controllable mechanical system. Finally, an example is given to illustrate the application of the results. (general)

167

A neuromuscular monitoring system based on a personal computer.  

Science.gov (United States)

We have developed a computerized neuromuscular monitoring system (NMMS) using commercially available subsystems, i.e., computer equipment, clinical nerve stimulator, force transducer, and strip-chart recorder. This NMMS was developed for acquisition and analysis of data for research and teaching purposes. Computer analysis of the muscle response to stimulation allows graphic and numeric presentation of the twitch response and calculated ratios. Since the system can store and recall data, research data can be accessed for analysis and graphic presentation. An IBM PC/AT computer is used as the central controller and data processor. The computer controls timing of the nerve stimulator output, initiates data acquisition, and adjusts the paper speed of the strip chart recorder. The data processing functions include establishing control response values (when no neuromuscular blockade is present), displaying force versus time and calculated data graphically and numerically, and storing these data for further analysis. The general purpose nature of the computer and strip chart recording equipment allow modification of the system primarily by changes in software. For example, new patterns of nerve stimulation, such as the posttetanic count, can be programmed into the computer system along with appropriate data display and analysis routines. The NMMS has functioned well in the operating room environment. We have had no episodes of electrocautery interference with the computer functions. The automated features have enhanced the utility of the NMMS.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1322977

White, D A; Hull, M

1992-07-01

168

Morphometric analysis of neuromuscular topography in the serratus anterior muscle.  

Science.gov (United States)

Groups of neurons form ordered topographic maps on their targets, and defining the mechanisms that develop such maps, and re-connect them after disruption, has biological as well as clinical importance. The neuromuscular system is an accessible and well-studied model for defining the principles that guide map formation, both during its development and its reformation after motor nerve damage. We present evidence for the expression of this map at the level of nerve terminal morphology and muscle fiber type in the serratus anterior muscle. Morphometric analyses indicate, first, a rostrocaudal difference in nerve terminal size depending on the ventral root of origin of the axons. Second, motor endplates are larger on type IIB than type IIA muscle fibers. Third, whereas IIB muscle fibers are distributed rather evenly along the rostrocaudal axis of the muscle, the more rostral type IIB fibers are preferentially innervated by anteriorly derived (C6) motor neurons, and more caudal IIB fibers are preferentially innervated by posteriorly derived (C7) motor neurons. This inference is supported by analysis of the size of nerve terminals formed in each muscle sector by rostral and caudal roots, and by evidence that the larger terminals are on IIB fibers. These results demonstrate a subcellular expression of neuromuscular topography in the serratus anterior muscle (SA) muscle in the form of differences in nerve terminal size. These results provide deeper insights into the organization of a neuromuscular system. They also offer a rationale for a topographic map, that is, to allow spinal motor centers to activate selectively different compartments within a muscle. PMID:16320309

Potluri, S; Lampa, S J; Norton, A S; Laskowski, M B

2006-03-01

169

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

Directory of Open Access Journals (Sweden)

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 transmissão neuromuscular é raro, e, como um corolário, um percentual significativo de uso de critérios eminentemente clínicos para considerar o paciente descurarizado. Registrou-se que, cerca de 30% dos anestesiologistas teve algum tipo de complicação decorrente do uso desses fármacos.JUSTIFICATIVA Y OBJETIVOS: Dados estadísticos referentes al uso de bloqueadores neuromusculares en Brasil son desconocidos. Este trabajo se propone el análisis estadístico de ese tópico. MÉTODO: Fueron compiladas 831 respuestas de un cuestionario llenado en parte por anestesiologistas presentes al 48º Congreso Brasileño de Anestesiologia en la ciudad de Recife, 2001 y en parte vía Internet, por anestesiologistas cuyas direcciones electrónicas constan en la página de la Sociedad Brasileña de Anestesiologia (www.sba.com.br. Fueron analizados los siguientes datos: tiempo de contacto con la especialidad, región donde actúan los anestesiologistas, uso de bloqueadores neuromusculares (BNM en orden de preferencia, indicaciones del uso de succinilcolina, uso del monitor de transmisión neuromuscular, criterios para considerar el paciente descurarizado, uso de neostigmina, forma de administración de los BNM y descripción de complicaciones observadas. RESULTADOS: La mayoría de los anestesiologistas en cuestión ejerce la profesión hace más de 11 años y el mayor número de respuestas fue proveniente de la región sudeste de Brasil. El BNM más empleado es el atracúrio, seguido de pancurónio y succinilcolina. La succinilcolina es más empleada en la inducción rápida y en niños (80% y 25% respectivamente. Monitores de la transmisión neuromuscular, 53% de los anestesiologistas nunca usan, y como criterio de recuperación, 92% consideran el paciente descurarizado mediante señales clínicas. En un 45% de las veces los profesionales emplean la neostigmina de forma rutinaria, y 94% administra los BNM bajo forma de bolus. Cerca del 30% registra que tuvieron complicación consecuente del uso de BNM. Las complicaciones más apuntadas fueron el bloqueo prolongado, el broncoespasmo gr

Maria Cristina Simões de Almeida

2004-12-01

170

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 48 [...] º 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 transmissão neuromuscular é raro, e, como um corolário, um percentual significativo de uso de critérios eminentemente clínicos para considerar o paciente descurarizado. Registrou-se que, cerca de 30% dos anestesiologistas teve algum tipo de complicação decorrente do uso desses fármacos. Abstract in spanish JUSTIFICATIVA Y OBJETIVOS: Dados estadísticos referentes al uso de bloqueadores neuromusculares en Brasil son desconocidos. Este trabajo se propone el análisis estadístico de ese tópico. MÉTODO: Fueron compiladas 831 respuestas de un cuestionario llenado en parte por anestesiologistas presentes al 4 [...] 8º Congreso Brasileño de Anestesiologia en la ciudad de Recife, 2001 y en parte vía Internet, por anestesiologistas cuyas direcciones electrónicas constan en la página de la Sociedad Brasileña de Anestesiologia (www.sba.com.br). Fueron analizados los siguientes datos: tiempo de contacto con la especialidad, región donde actúan los anestesiologistas, uso de bloqueadores neuromusculares (BNM) en orden de preferencia, indicaciones del uso de succinilcolina, uso del monitor de transmisión neuromuscular, criterios para considerar el paciente descurarizado, uso de neostigmina, forma de administración de los BNM y descripción de complicaciones observadas. RESULTADOS: La mayoría de los anestesiologistas en cuestión ejerce la profesión hace más de 11 años y el mayor número de respuestas fue proveniente de la región sudeste de Brasil. El BNM más empleado es el atracúrio, seguido de pancurónio y succinilcolina. La succinilcolina es más empleada en la inducción rápida y en niños (80% y 25% respectivamente). Monitores de la transmisión neuromuscular, 53% de los anestesiologistas nunca usan, y como criterio de recuperación, 92% consideran el paciente descurarizado mediante señales clínicas. En un 45% de las veces los profesionales emplean la neostigmina de forma rutinaria, y 94% administra los BNM bajo forma de bolus. Cerca del 30% registra que tuvieron complicación consecuent

Maria Cristina Simões de, Almeida.

2004-12-01

171

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

Science.gov (United States)

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…

Richardson, Charles; Simmons, Roger W.

172

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

Science.gov (United States)

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…

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

2010-01-01

173

Control rod drive mechanism vent valve assembly  

International Nuclear Information System (INIS)

A closure insert assembly for a control rod drive mechanism that has incorporated therein a vent valve arrangement which permits the release of air trapped in the nuclear reactor during the filling of the primary coolant system therein and allows the entrance of air into the reactor for the draining of same. To accomplish this, the vent valve is of the ball type which engages two oppositely disposed conical ball seats, one of which is allowed to move laterally with respect to the other, causing the ball and ball seats to be ''self-centering'' and resulting in a uniform compressive force being applied over minor circumferences on the ball. The use of conical ball seats, one of which is laterally movable, also permits the axes of the conical ball seats to be non-parallel and/or non-concentric without hindering the operation and effectiveness of the vent valve

174

Discrete Mechanics and Optimal Control: an Analysis  

CERN Document Server

The optimal control of a mechanical system is of crucial importance in many realms. Typical examples are the determination of a time-minimal path in vehicle dynamics, a minimal energy trajectory in space mission design, or optimal motion sequences in robotics and biomechanics. In most cases, some sort of discretization of the original, infinite-dimensional optimization problem has to be performed in order to make the problem amenable to computations. The approach proposed in this paper is to directly discretize the variational description of the system's motion. The resulting optimization algorithm lets the discrete solution directly inherit characteristic structural properties from the continuous one like symmetries and integrals of the motion. We show that the DMOC approach is equivalent to a finite difference discretization of Hamilton's equations by a symplectic partitioned Runge-Kutta scheme and employ this fact in order to give a proof of convergence. The numerical performance of DMOC and its relationsh...

Ober-Bloebaum, S; Marsden, J E

2008-01-01

175

Papel da vitamina D na função neuro-muscular / Role of vitamin D in the neuro-muscular function  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A vitamina D, através de suas ações no intestino, rim, osso e glândulas paratiróides, é um hormônio fundamental para a homeostase do cálcio e para o desenvolvimento de um esqueleto saudável. Além disso, receptores deste hormônio podem ser encontrados em quase todos os tecidos do organismo e outras a [...] ções não relacionadas ao metabolismo mineral têm sido imputadas a ele. Na célula muscular esquelética, a vitamina D atua através do mecanismo clássico de ligação a um receptor nuclear e também através da ligação a um receptor de membrana, realizando ações que envolvem o transporte de cálcio, a síntese protéica e a velocidade de contração muscular. Clinicamente, a deficiência de vitamina D, que é bastante comum em idosos, inclusive em nosso país, tem sido relacionada a um aumento da incidência de quedas, a uma diminuição da força muscular e a uma deterioração do equilíbrio, avaliada pela oscilação do corpo na postura ereta. Por outro lado, tem sido demonstrado que a suplementação associada de cálcio e vitamina D em idosos deficientes contribui para melhoria destes aspectos da função neuro-muscular. Nesta revisão, serão discutidos os mecanismos conhecidos envolvidos na associação entre vitamina D e função neuro-muscular, e também a suplementação de vitamina D e cálcio na prevenção de fraturas osteoporóticas não-vertebrais sob a perspectiva dos efeitos neuro-musculares. Abstract in english Through its action in the kidney, intestines, bone and parathyroid glands vitamin D is a major regulator of calcium homeostasis and for the development of a healthy skeleton. Moreover, receptors for this hormone are present in almost all body tissues and other actions which are not related to the mi [...] neral metabolism have been imputed to it. In the skeletal muscle cell, vitamin D acts through the classic mechanism of binding to a nuclear receptor and also by binding to a membrane receptor, carrying out actions that involve calcium transport, protein synthesis and kinetics of muscle contraction. Clinically, vitamin D deficiency, which is very common among the elderly, including the ones in our country, has been related to an increase in the incidence of falls, as well as the reduction of muscle strength and deterioration of body sway, evaluated by the oscillation of the body in the erect position. On the other hand, it has been demonstrated that supplementation of calcium associated to vitamin D in deficient elderly contributes to the improvement of these aspects of the neuro-muscular function. In this review, the mechanisms involved in the association between vitamin D and neuro-muscular function will be discussed, as well as the supplementation of vitamin D and calcium to prevent non-vertebral osteoporotic fractures under the perspective of the neuro-muscular effects.

Márcia A. Carneiro, Pedrosa; Marise Lazaretti, Castro.

2005-08-01

176

Facilitatory effects of piracetam on excitability of motor nerve terminals and neuromuscular transmission.  

Science.gov (United States)

The possible in vivo facilitatory effects of the pyrrolidine acetamide no-otropic agent piracetam on neuromuscular transmission, were studied based upon reports of enhancement of central cholinergic function. Piracetam was shown to antagonize the lethal effects of the neuromuscular blocking agent hemicholinium-3 (HC-3), in female CF-1 mice when administered in a dose of 100 mg/kg (i.p.) simultaneously with HC-3. A 30 mg/kg (i.p.) dose of piracetam was ineffective by itself, although it potentiated the protective effects of choline (25 mg/kg i.p.). The analogs of piracetam, aniracetam, oxiracetam, pramiracetam and dupracetam also significantly antagonized the lethality of HC-3 at doses over a 30-300 mg/kg range. The acute facilitatory properties of piracetam on neuromuscular transmission were examined in more detail in vivo in the soleus nerve muscle preparation of the cat. A 100 mg/kg (i.v.) dose of piracetam, while having no effect on its own, significantly enhanced the ability of a 200 micrograms/kg (i.v.) dose of edrophonium to produce a potentiation of muscle contraction dependent on repetitive discharges in the soleus motor nerve terminals. In preparations in which the motor nerve terminals of the soleus were in a partially degenerated state as a result of section of the motor axons 48 hr earlier, piracetam acted to restore their sensitivity to edrophonium. Furthermore, in both normal and partially degenerated preparations, piracetam significantly decreased the neuromuscular blocking effects of a 150 micrograms/kg (i.v.) dose of d-tubocurarine. The mechanism of the neuromuscular facilitatory effects of piracetam on neuromuscular transmission is discussed in terms of an enhanced excitability of motor nerve terminals together with an action to increase the synthesis and/or release of acetylcholine. PMID:2829047

Hall, E D; Von Voigtlander, P F

1987-11-01

177

Clinical use of creatine in neuromuscular and neurometabolic disorders.  

Science.gov (United States)

Many of the neuromuscular (e.g., muscular dystrophy) and neurometabolic (e.g., mitochondrial cytopathies) disorders share similar final common pathways of cellular dysfunction that may be favorably influenced by creatine monohydrate (CrM) supplementation. Studies using the mdx model of Duchenne muscular dystrophy have found evidence of enhanced mitochondrial function, reduced intra-cellular calcium and improved performance with CrM supplementation. Clinical trials in patients with Duchenne and Becker's muscular dystrophy have shown improved function, fat-free mass, and some evidence of improved bone health with CrM supplementation. In contrast, the improvements in function in myotonic dystrophy and inherited neuropathies (e.g., Charcot-Marie-Tooth) have not been significant. Some studies in patients with mitochondrial cytopathies have shown improved muscle endurance and body composition, yet other studies did not find significant improvements in patients with mitochondrial cytopathy. Lower-dose CrM supplementation in patients with McArdle's disease (myophosphorylase deficiency) improved exercise capacity, yet higher doses actually showed some indication of worsened function. Based upon known cellular pathologies, there are potential benefits from CrM supplementation in patients with steroid myopathy, inflammatory myopathy, myoadenylate deaminase deficiency, and fatty acid oxidation defects. Larger randomized control trials (RCT) using homogeneous patient groups and objective and clinically relevant outcome variables are needed to determine whether creatine supplementation will be of therapeutic benefit to patients with neuromuscular or neurometabolic disorders. Given the relatively low prevalence of some of the neuromuscular and neurometabolic disorders, it will be necessary to use surrogate markers of potential clinical efficacy including markers of oxidative stress, cellular energy charge, and gene expression patterns. PMID:18652078

Tarnopolsky, Mark A

2007-01-01

178

Neuromuscular contributions to age-related weakness  

Science.gov (United States)

Age-related physiological change of neuromuscular function is not a linear process and is likely influenced by various biological and behavioral factors (e.g., genetics, nutrition, physical activity level, comorbidities, etc.). These factors contribute to heterogeneity among older adults, which chal...

179

Neuromuscular Effects of Acute Organophosphate Poisoning  

Directory of Open Access Journals (Sweden)

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

Taylan Pekoz

2014-08-01

180

Neural mechanisms of hair growth control.  

Science.gov (United States)

Clinical and experimental observations have long suggested that skin nerves have "trophic" functions in hair follicle development, growth and/or cycling, even though the molecular and cellular basis of the underlying neuroepithelial interactions has remained obscure. Here, we critically review currently available evidence arguing in favor of or against the existence of neural mechanisms of hair growth control, and outline why the murine hair cycle provides an excellent experimental system for characterizing and manipulating piloneural interactions. Summarizing relevant, recent data from the C57BL/6 mouse model, it is pointed out that the sensory and autonomic innervation of normal pelage hair follicles, the substance P skin content, and cutaneous mast cell-nerve contacts show striking changes during synchronized hair follicle cycling. Furthermore, the murine hair follicle appears to be both a source and a target of neurotrophins, whereas neuropharmacologic manipulations alter murine hair follicle cycling in vivo. For example, anagen is induced by substance P or adrenocorticotropin (ACTH), and by the experimentally triggered release of neuropeptides from sensory nerves and of neurotransmitters from adrenergic nerves. Taken together, this argues in favor of neuroepithelial interactions as regulatory elements in hair growth control and suggests that the study of piloneural interactions promises important insights into general principles of neuroepithelial communication, namely during epithelial morphogenesis and remodeling. We delineate a hypothetical working model of piloneural interactions and propose that targeted manipulations deserve systematic exploration as a novel strategy for managing hair growth disorders. PMID:9487018

Paus, R; Peters, E M; Eichmüller, S; Botchkarev, V A

1997-08-01

181

Effects of aquatic balance training and detraining on neuromuscular performance and balance in healthy middle aged male  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Since disorders in neuromuscular performance and imbalance are the main cause of fallingamong the middle aged, their aspects including rehabilitation of balance are the main concern theresearchers attend to them. The aim of this study was to determine the effects of eight weeks aquaticbalance training (ABT and detraining on neuromuscular performance and balance in healthy middle agedmale.Materials and Methods: Thirty adult male subjects were randomized into two groups of ABT and control(n=15 per group. Berg balance scale, Timed Up and Go and 5-Chair stand tests, as they are indicators ofbalance and neuromuscular performance in older subjects, were taken as pretest and post-test and after four,six, and eight weeks of detraining as well. The ABT consisted of the sessions that lasted one hour, threetimes a week, for eight weeks.Results: Results showed that neuromuscular performance and balance improved significantly in ABTgroup (P 0.05.Conclusion: ABT can affect neuromuscular performance and balance in healthy middle aged male, andreduce the probability of falling among them. Moreover, the effects of these training are persistent afterdetraining periods. Hence, ABT can be recommended as an effective neuromuscular and balance training inhealthy middle aged male

Ali Abbasi

2012-04-01

182

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

Directory of Open Access Journals (Sweden)

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.

Patricia Fernández

2010-12-01

183

A Method to Measure the Relationship Between Biodynamic Feedthrough and Neuromuscular Admittance.  

Science.gov (United States)

Biodynamic feedthrough (BDFT) refers to a phenomenon where accelerations cause involuntary limb motions, which can result in unintentional control inputs that can substantially degrade manual control. It is known that humans can adapt the dynamics of their limbs by adjusting their neuromuscular settings, and it is likely that these adaptations have a large influence on BDFT. The goal of this paper is to present a method that can provide evidence for this hypothesis. Limb dynamics can be described by admittance, which is the causal dynamic relation between a force input and a position output. This paper presents a method to simultaneously measure BDFT and admittance in a motion-based simulator. The method was validated in an experiment. Admittance was measured by applying a force disturbance signal to the control device; BDFT was measured by applying a motion disturbance signal to the motion simulator. To allow distinguishing between the operator's responses to each disturbance signal, the perturbation signals were separated in the frequency domain. To show the impact of neuromuscular adaptation, subjects were asked to perform three different control tasks, each requiring a different setting of the neuromuscular system (NMS). Results show a dependence of BDFT on neuromuscular admittance: A change in neuromuscular admittance results in a change in BDFT dynamics. This dependence is highly relevant when studying BDFT. The data obtained with the proposed measuring method provide insight in how exactly the settings of the NMS influence the level of BDFT. This information can be used to gain fundamental knowledge on BDFT and also, for example, in the development of a canceling controller. PMID:21349792

Venrooij, Joost; Abbink, David A; Mulder, Mark; van Paassen, Marinus M; Mulder, Max

2011-02-24

184

Research Group Introduction : Mechanical Control Engineering Laboratory, Mechanical Engineering Department, Shibaura Institute of Technology  

Science.gov (United States)

Mechanical Control Engineering Laboratory focuses on the control theory and implementation for the robotic applications. The research themes include network based tele-operation, mobile robots control for network relay, autonomous outdoor mobile robot and biped robot.

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185

Brain mechanisms that control sleep and waking  

Science.gov (United States)

This review paper presents a brief historical survey of the technological and early research that laid the groundwork for recent advances in sleep-waking research. A major advance in this field occurred shortly after the end of World War II with the discovery of the ascending reticular activating system (ARAS) as the neural source in the brain stem of the waking state. Subsequent research showed that the brain stem activating system produced cortical arousal via two pathways: a dorsal route through the thalamus and a ventral route through the hypothalamus and basal forebrain. The nuclei, pathways, and neurotransmitters that comprise the multiple components of these arousal systems are described. Sleep is now recognized as being composed of two very different states: rapid eye movements (REMs) sleep and non-REM sleep. The major findings on the neural mechanisms that control these two sleep states are presented. This review ends with a discussion of two current views on the function of sleep: to maintain the integrity of the immune system and to enhance memory consolidation.

Siegel, Jerome

186

Mechanically and optically controlled graphene valley filter  

Energy Technology Data Exchange (ETDEWEB)

We theoretically investigate the valley-dependent electronic transport through a graphene monolayer modulated simultaneously by a uniform uniaxial strain and linearly polarized light. Within the Floquet formalism, we calculate the transmission probabilities and conductances of the two valleys. It is found that valley polarization can appear only if the two modulations coexist. Under a proper stretching of the sample, the ratio of the light intensity and the light frequency squared is important. If this quantity is small, the electron transport is mainly contributed by the valley-symmetric central band and the conductance is valley unpolarized; but when this quantity is large, the valley-asymmetric sidebands also take part in the transport and the valley polarization of the conductance appears. Furthermore, the degree of the polarization can be tuned by the strain strength, light intensity, and light frequency. It is proposed that the detection of the valley polarization can be realized utilizing the valley beam splitting. Thus, a graphene monolayer can be used as a mechanically and optically controlled valley filter.

Qi, Fenghua; Jin, Guojun, E-mail: gjin@nju.edu.cn [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China)

2014-05-07

187

Mechanically and optically controlled graphene valley filter  

International Nuclear Information System (INIS)

We theoretically investigate the valley-dependent electronic transport through a graphene monolayer modulated simultaneously by a uniform uniaxial strain and linearly polarized light. Within the Floquet formalism, we calculate the transmission probabilities and conductances of the two valleys. It is found that valley polarization can appear only if the two modulations coexist. Under a proper stretching of the sample, the ratio of the light intensity and the light frequency squared is important. If this quantity is small, the electron transport is mainly contributed by the valley-symmetric central band and the conductance is valley unpolarized; but when this quantity is large, the valley-asymmetric sidebands also take part in the transport and the valley polarization of the conductance appears. Furthermore, the degree of the polarization can be tuned by the strain strength, light intensity, and light frequency. It is proposed that the detection of the valley polarization can be realized utilizing the valley beam splitting. Thus, a graphene monolayer can be used as a mechanically and optically controlled valley filter

188

Multicategory classification of 11 neuromuscular diseases based on microarray data using support vector machine.  

Science.gov (United States)

We applied multicategory machine learning methods to classify 11 neuromuscular disease groups and one control group based on microarray data. To develop multicategory classification models with optimal parameters and features, we performed a systematic evaluation of three machine learning algorithms and four feature selection methods using three-fold cross validation and a grid search. This study included 114 subjects of 11 neuromuscular diseases and 31 subjects of a control group using microarray data with 22,283 probe sets from the National Center for Biotechnology Information (NCBI). We obtained an accuracy of 100%, relative classifier information (RCI) of 1.0, and a kappa index of 1.0 by applying the models of support vector machines one-versus-one (SVM-OVO), SVM one-versus-rest (OVR), and directed acyclic graph SVM (DAGSVM), using the ratio of genes between categories to within-category sums of squares (BW) feature selection method. Each of these three models selected only four features to categorize the 12 groups, resulting in a time-saving and cost-effective strategy for diagnosing neuromuscular diseases. In addition, a gene symbol, SPP1 was selected as the top-ranked gene by the BW method. We confirmed relationships between the gene (SPP1) and Duchenne muscular dystrophy (DMD) from a previous study. With our models as clinically helpful tools, neuromuscular diseases could be classified quickly using a computer, thereby giving a time-saving, cost-effective, and accurate diagnosis. PMID:25570735

Soo Beom Choi; Jee Soo Park; Jai Won Chung; Tae Keun Yoo; Deok Won Kim

2014-08-01

189

Towards a Unified Representation of Mechanisms for Robotic Control Software  

OpenAIRE

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.

Antonio Diaz-Calderon; Hari Das Nayar; Nesnas, Issa A. D.; Kim, Won S.

2008-01-01

190

Towards a Unified Representation of Mechanisms for Robotic Control Software  

Directory of Open Access Journals (Sweden)

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.

Antonio Diaz-Calderon

2008-11-01

191

Effects of neuromuscular blocking agents on central respiratory chemosensitivity in newborn rats  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Neuromuscular blocking agents suppress central respiratory activity through their inhibitory effects on preinspiratory neurons and the synaptic drive from preinspiratory neurons to inspiratory neurons. Central CO2-chemosensitive areas, which partly consist of CO2-excited neurons, in the rostral vent [...] rolateral medulla are thought to provide tonic drive to the central respiratory network and involve cholinergic mechanisms, which led us to hypothesize that neuromuscular blocking agents can inhibit CO2-excited neurons and attenuate respiratory CO2 responsiveness. To test this hypothesis, we used isolated brainstem-spinal cord preparations from newborn rats. The increase of C4 burst frequency induced by a hypercapnic superfusate, i.e. respiratory CO2 responsiveness, was suppressed by the application of neuromuscular blocking agents, either d-tubocurarine (10, 100?M) or vecuronium (100?M). These agents (40?M) also induced hyperpolarization and decreases in firing frequency of CO2-excited neurons in the rostral ventrolateral medulla. Our results demonstrate that neuromuscular blocking agents inhibit CO2-excited tonic firing neurons and attenuate respiratory CO2 responsiveness.

SHIGEKI, SAKURABA; SHUN-ICHI, KUWANA; LARS I, ERIKSSON; YASUMASA, OKADA; RYOICHI, OCHIAI; MASANORI, KASHIWAGI; EIKI, HATORI; STEN G. E., LINDAHL; JUNZO, TAKEDA.

192

Effects of neuromuscular blocking agents on central respiratory chemosensitivity in newborn rats  

Directory of Open Access Journals (Sweden)

Full Text Available Neuromuscular blocking agents suppress central respiratory activity through their inhibitory effects on preinspiratory neurons and the synaptic drive from preinspiratory neurons to inspiratory neurons. Central CO2-chemosensitive areas, which partly consist of CO2-excited neurons, in the rostral ventrolateral medulla are thought to provide tonic drive to the central respiratory network and involve cholinergic mechanisms, which led us to hypothesize that neuromuscular blocking agents can inhibit CO2-excited neurons and attenuate respiratory CO2 responsiveness. To test this hypothesis, we used isolated brainstem-spinal cord preparations from newborn rats. The increase of C4 burst frequency induced by a hypercapnic superfusate, i.e. respiratory CO2 responsiveness, was suppressed by the application of neuromuscular blocking agents, either d-tubocurarine (10, 100?M or vecuronium (100?M. These agents (40?M also induced hyperpolarization and decreases in firing frequency of CO2-excited neurons in the rostral ventrolateral medulla. Our results demonstrate that neuromuscular blocking agents inhibit CO2-excited tonic firing neurons and attenuate respiratory CO2 responsiveness.

SHIGEKI SAKURABA

2005-01-01

193

[Neuromuscular deficits in chronic ankle instability. Frequency and significance - multicenter study].  

Science.gov (United States)

The peroneal reaction time (PRT) is used in the assessment of neuromuscular deficits in chronic functional ankle instability. Powered by the Editorial Manager and Preprint Manager from Aries Systems Corporation the present study was conducted to determine the PRT in a large collective of patients with chronic ankle instability because it is unclear if this parameter of neuromuscular deficit is prolonged. In this study 186 patients underwent a diagnostic algorithm consisting of anamnesis, clinical examination, X-ray and determination of the PRT on a tilting platform. A prolonged PRT as a manifestation of a neuromuscular deficit could be detected in the majority of the patients (n?=?143, 77%). Comparing the affected and healthy legs 77 patients (41%) showed a significant difference in talar shift (p?=?0.002) and talar tilt (p?=?0.04) in the radiological stress views. Of these 77 patients only 15 (8%) showed radiological evidence of a mechanical problem. As a consequence of recurring ankle sprains a post-traumatic deficit in proprioception has to be expected in most cases. In general a conservative therapy approach should be followed including specific training to improve neuromuscular and proprioceptive deficits. PMID:23652929

Schmidt, R; Becker, H P; Rauhut, F; Tannheimer, M

2014-08-01

194

Neuromuscular and biomechanical compensation for wing asymmetry in insect hovering flight.  

Science.gov (United States)

Wing damage is common in flying insects and has been studied using a variety of approaches to assess its biomechanical and fitness consequences. Results of these studies range from strong to nil effect among the variety of species, fitness measurements and damage modes studied, suggesting that not all damage modes are equal and that insects may be well adapted to compensate for some types of damage. Here, we examine the biomechanical and neuromuscular means by which flying insects compensate for asymmetric wing damage, which is expected to produce asymmetric flight forces and torques and thus destabilize the animal in addition to reducing its total wing size. We measured the kinematic and neuromuscular responses of hawkmoths (Manduca sexta) hovering in free flight with asymmetrically damaged wings via high-speed videography and extracellular neuromuscular activity recordings. The animals responded to asymmetric wing damage with asymmetric changes to wing stroke amplitude sufficient to restore symmetry in lift production. These asymmetries in stroke amplitude were significantly correlated with bilateral asymmetries in the timing of activation of the dorsal ventral muscle among and within trials. Correspondingly, the magnitude of wing asymmetry was significantly, although non-linearly, correlated with the magnitude of the neuromuscular response among individuals. The strongly non-linear nature of the relationship suggests that active neural compensation for asymmetric wing damage may only be necessary above a threshold (>12% asymmetry in wing second moment of area in this case) below which passive mechanisms may be adequate to maintain flight stability. PMID:22771747

Fernández, María José; Springthorpe, Dwight; Hedrick, Tyson L

2012-10-15

195

Neuromuscular paralysis caused by tick envenomation.  

Science.gov (United States)

The Australian scrub-tick Ixodes holocyclus causes a series of significant toxic effects in its victims. The most important feature of tick envenomation is neuromuscular paralysis. Children poisoned by ticks may manifest only local motoneural effects, usually facial paralysis. Progressive ascending flaccid paralysis occurs if the removal of an embedded tick is delayed. The specific neurological features of tick-bite are discussed in the light of a series of 6 children who all showed signs of tick paralysis. Tick venom is known to slow nerve conduction, and may have a botulinum-like effect at the neuromuscular junction. The literature on the neurological effects of tick-envenomation is reviewed. PMID:915536

Pearn, J

1977-10-01

196

Overview of neuromuscular disorders affecting respiratory function.  

Science.gov (United States)

A great many neuromuscular disorders affect respiratory function. This article focuses on neuropathic and myopathic disorders that weaken the diaphragm and respiratory muscles. This discussion gives a general overview and attempts to update the reader on recent pathophysiological insights and developments in therapy. Among the disorders discussed, amyotrophic lateral sclerosis, poliomyelitis, postpolio syndrome, Kennedy syndrome, and spinal muscular atrophy are motor neuron diseases. Brachial plexitis and isolated unilateral or bilateral phrenic neuropathies can also weaken the diaphragm significantly. Peripheral neuropathies affecting respiration are primarily acute disorders such as Guillain-Barré syndrome, porphyria, and critical illness neuropathy, but chronic diseases such as chronic inflammatory demyelinating polyneuropathy (CIDP) and Charcot-Marie-Tooth disease (CMT) can also cause respiratory insufficiency. Disorders of neuromuscular transmission such as Lambert-Eaton syndrome, botulism, and myasthenia gravis often affect respiration. Many muscle diseases also affect pulmonary function, including polymyositis/dermatomyositis, muscular dystrophy, hereditary channel disorders, mitochondrial encephalomyopathies, acid maltase deficiency, and congenital myopathy. PMID:16088611

Gilchrist, James M

2002-06-01

197

Respiratory failure and sleep in neuromuscular disease.  

OpenAIRE

Sleep hypoxaemia in non-rapid eye movement (non-REM) and rapid eye movement (REM) sleep was examined in 20 patients with various neuromuscular disorders with reference to the relation between oxygen desaturation during sleep and daytime lung and respiratory muscle function. All the patients had all night sleep studies performed and maximum inspiratory and expiratory mouth pressures (PI and Pemax), lung volumes, single breath transfer coefficient for carbon monoxide (KCO), and daytime arterial...

Bye, P. T.; Ellis, E. R.; Issa, F. G.; Donnelly, P. M.; Sullivan, C. E.

1990-01-01

198

Reconstruction of the Neuromuscular Junction Connectome  

OpenAIRE

Motivation: Unraveling the structure and behavior of the brain and central nervous system (CNS) has always been a major goal of neuroscience. Understanding the wiring diagrams of the neuromuscular junction connectomes (full connectivity of nervous system neuronal components) is a starting point for this, as it helps in the study of the organizational and developmental properties of the mammalian CNS. The phenomenon of synapse elimination during developmental stages of the neuronal circuitry i...

Srinivasan, Ranga; Wong, Stephen T. C.; Li, Qing; Lichtman, Jeff; Lu, Ju; Zhou, Xiaobo

2010-01-01

199

Neuromuscular Fatigue During 200 M Breaststroke  

OpenAIRE

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 la...

Ana Conceição; Anto?nio J Silva, Tiago Barbosa

2014-01-01

200

Neuromuscular Diseases Associated with HIV-1 Infection  

OpenAIRE

Neuromuscular disorders are common in HIV, occurring at all stages of disease and affecting all parts of the peripheral nervous system. These disorders have diverse etiologies including HIV itself, immune suppression and dysregulation, co-morbid illnesses and infections, and side effects of medications. In this article, we review the following HIV-associated conditions: distal symmetric polyneuropathy, inflammatory demyelinating polyneuropathy, mononeuropathy, mononeuropathy multiplex, autono...

Robinson-papp, Jessica; Simpson, David M.

2009-01-01

201

Diagnosis of Neuromuscular Disorders Using Softcomputing Techniques  

OpenAIRE

Biomedical signals are collection of electrical signals which generated from any organ that signal represents a physical variable of interest. Electromyography (EMG) is a technique for evaluating and recording of electrical activities produced from skeletal muscles. There are so many applications of EMG signals. Major interests lies in the field of clinical as well as biomedical engineering.EMG is used as a diagnostic tool for identifying neuromuscular disorders .Motor unit action potentials ...

Akhila Devi.B.V; Suja Priyadharsini, S.

2013-01-01

202

Neuromuscular Manifestations of West Nile Virus Infection  

OpenAIRE

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 respo...

Arturoleis, A.; DobrivojeSStokic

2012-01-01

203

Molecular diagnosis of inheritable neuromuscular disorders. Part II: Application of genetic testing in neuromuscular disease.  

Science.gov (United States)

Molecular genetic advances have led to refinements in the classification of inherited neuromuscular disease, and to methods of molecular testing useful for diagnosis and management of selected patients. Testing should be performed as targeted studies, sometimes sequentially, but not as wasteful panels of multiple genetic tests performed simultaneously. Accurate diagnosis through molecular testing is available for the vast majority of patients with inherited neuropathies, resulting from mutations in three genes (PMP22, MPZ, and GJB1); the most common types of muscular dystrophies (Duchenne and Becker, facioscapulohumeral, and myotonic dystrophies); the inherited motor neuron disorders (spinal muscular atrophy, Kennedy's disease, and SOD1 related amyotrophic lateral sclerosis); and many other neuromuscular disorders. The role of potential multiple genetic influences on the development of acquired neuromuscular diseases is an increasingly active area of research. PMID:15704143

Greenberg, Steven A; Walsh, Ronan J

2005-04-01

204

Estimulação elétrica neuromuscular na reversão da ossificação heterotópica / Neuromuscular electric stimulation in heterotropic ossification regression  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A ossificação heterotópica é uma complicação freqüente após a lesão medular. Os avanços graduais no campo da fisiopatologia, reabilitação e novos métodos de tratamento são uma esperança para a reversão do quadro clínico do lesado medular num futuro próximo. O objetivo desse estudo é avaliar a respos [...] ta da ossificação heterotópica das articulações coxo femorais à estimulação elétrica neuromuscular em pacientes tetraplégicos após trauma raquimedular. Seis pacientes foram submetidos à estimulação elétrica neuromuscular por um período médio de 16,6 meses, sendo avaliados radiologicamente. Foi identificada a melhora radiológica em dois pacientes e a não progressão do quadro nos demais. A estimulação elétrica neuromuscular em lesados medulares pode ser um método válido no tratamento da ossificação heterotópica e prevenção de sua progressão. Abstract in english Heterotropic ossification is a common complication after spinal cord injury. Gradual advancements in the physiopathology and rehabilitation fields, and new treatment methods are a hope for the recovery of the clinical picture of injured individuals in the near future. The objective of this study was [...] to evaluate the heterotropic ossification response of the thigh-femoral joints to neuromuscular electric stimulation in tetraplegic patients after rachial-medullar trauma. Six patients were submitted to neuromuscular electric stimulation for an average period of 16.6 months, being evaluated for X-ray imaging. Improvements on X-ray images were identified in two patients and the non-progression of the picture was observed in the remaining patients. Neuromuscular electric stimulation in spinal cord-injured individuals could be a useful method for treating heterotropic ossification and related progression prevention.

Daniel Bechara Jacob, Ferreira; Henrique Cambraia, Lippelt; Alberto, Cliquet Júnior.

205

Neuromuscular induced phonation in a human ex vivo perfused larynx preparation  

OpenAIRE

Considering differences in laryngeal anatomy, degree of control, and range of voice qualities between animals and humans, investigations of the neuromuscular process of voice control are better conducted using a living human larynx in which parametric stimulation of individual laryngeal muscles is possible. Due to difficulties in access and monitoring of laryngeal muscle activities, such investigations are impossible in living human subject experiments. This study reports the recent success i...

Berke, Gerald; Mendelsohn, Abie H.; Scott Howard, Nelson; Zhang, Zhaoyan

2013-01-01

206

Strength training induced adaptations in neuromuscular function of premenopausal women with fibromyalgia: comparison with healthy women  

OpenAIRE

OBJECTIVE—To investigate the effects of 21 weeks' progressive strength training on neuromuscular function and subjectively perceived symptoms in premenopausal women with fibromyalgia (FM).?METHODS—Twenty one women with FM were randomly assigned to experimental (FMT) or control (FMC) groups. Twelve healthy women served as training controls (HT). The FMT and HT groups carried out progressive strength training twice a week for 21 weeks. The major outcome measures were muscle strength and...

Hakkinen, A.; Hakkinen, K.; Hannonen, P.; Alen, M.

2001-01-01

207

Analysis and control of underactuated mechanical systems  

CERN Document Server

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...

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

2014-01-01

208

Mechanisms and Control of Silk-based Electrospinning  

OpenAIRE

Silk fibroin (SF) nanofibers, formed through electrospinning, have attractive utility in regenerative medicine due to the biocompatibility, mechanical properties and tailorable degradability. The mechanism of SF electrospun nanofiber formation was studied to gain new insight into the formation and control of nanofibers. SF electrospinning solutions with different nanostructures (nanospheres or nanofilaments) were prepared by controlling the drying process during the preparation of regenerated...

Zhang, Feng; Zuo, Baoqi; Fan, Zhihai; Xie, Zonggang; Lu, Qiang; Zhang, Xueguang; Kaplan, David L.

2012-01-01

209

Coherent, mechanical control of a single electronic spin  

CERN Document Server

The ability to control and manipulate spins via electrical, magnetic and optical means has generated numerous applications in metrology and quantum information science in recent years. A promising alternative method for spin manipulation is the use of mechanical motion, where the oscillation of a mechanical resonator can be magnetically coupled to a spins magnetic dipole, which could enable scalable quantum information architectures9 and sensitive nanoscale magnetometry. To date, however, only population control of spins has been realized via classical motion of a mechanical resonator. Here, we demonstrate coherent mechanical control of an individual spin under ambient conditions using the driven motion of a mechanical resonator that is magnetically coupled to the electronic spin of a single nitrogen-vacancy (NV) color center in diamond. Coherent control of this hybrid mechanical/spin system is achieved by synchronizing pulsed spin-addressing protocols (involving optical and radiofrequency fields) to the moti...

Hong, Sungkun; Maletinsky, Patrick; Walsworth, Ronald L; Lukin, Mikhail D; Yacoby, Amir

2012-01-01

210

Controlling a mechanical oscillator with a tunable coherent feedback network  

CERN Document Server

We demonstrate a fully cryogenic microwave feedback network composed of distinct superconducting devices interconnected by waveguides and designed to control a mechanical oscillator coupled to one of the devices. The network is partitioned into an electromechanical device to be controlled and a dynamically tunable controller that coherently receives, processes and feeds back continuous microwave signals that modify the dynamics and readout of the mechanical state. While previous electromechanical systems represent some compromise between efficient control and efficient readout of the mechanical state, as set by the electromagnetic decay rate, this flexible controller yields a closed-loop network that can be dynamically and continuously tuned between both extremes much faster than the mechanical response time. We demonstrate that the microwave decay rate may be modulated by at least a factor of 10 at a rate greater than $10^4$ times the mechanical response rate.

Kerckhoff, Joseph; Ku, H S; Kindel, William F; Cicak, Katarina; Simmonds, Raymond W; Lehnert, K W

2012-01-01

211

Avaliação da ativação neuromuscular em indivíduos com escoliose através da eletromiografia de superfície Assessment of neuromuscular activation in individuals with scoliosis using surface electromyography  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: O objetivo desse estudo foi verificar o potencial da eletromiografia (EMG de superfície para a avaliação da eficiência neuromuscular e da fadiga muscular localizada dos extensores lombares em indivíduos com escoliose. MÉTODOS: Participaram deste estudo 20 indivíduos divididos igualmente em dois grupos, (1 Grupo com Escoliose e (2 Grupo Controle, que foram submetidos a um teste de indução dos músculos extensores lombares a fadiga, o qual constituiu da realização de uma contração voluntária máxima isométrica (CVM, e realização de um teste com esforço a 80% da CVM. Foram coletados simultaneamente sinais de força e eletromiográficos (sinal EMG. O sinal EMG foi processado no domínio da freqüência, utilizando-se a transformada rápida de Fourier (FFT, por meio da mediana da freqüência (MF, e no domínio do tempo, pelo cálculo do valor root mean square (RMS. Os dados foram submetidos a uma análise de variância one-way para verificar as diferenças entre os dois grupos. Para verificar a simetria entre os lados direito e esquerdo, foi realizado o teste t pareado. O nível de significância adotado foi 0,05. RESULTADOS: os resultados demonstraram que indivíduos com escoliose apresentaram: (1 simetria de ativação neuromuscular entre os lados; (2 menor eficiência neuromuscular; (3 maior capacidade de resistir a fadiga; e (4 valores de força 42,6% menores que os indivíduos do GC. CONCLUSÕES: Os resultados sugerem que a EMG de superfície corresponde a um efetivo instrumento de avaliação funcional da escoliose, embora o protocolo estabelecido tenha limitado a participação dos indivíduos com escoliose, do ponto de vista da eficiência neuromuscular.OBJECTIVE: The aim of this study was to investigate the potential of surface electromyography (EMG for assessing neuromuscular efficiency and localized muscle fatigue in the lumbar extensors, in individuals with scoliosis. METHODS: Twenty individuals participated in this study, divided equally into two groups: (1 Scoliosis Group and (2 Control Group. These subjects underwent a fatigue induction test on their lumbar extensor muscles, consisting of one maximum voluntary isometric contraction (MVIC followed by a test at 80% of the MVIC effort. Force and EMG signals were collected simultaneously. The EMG signal was processed in the frequency domain by means of fast Fourier transforms using the median frequency; and in the time domain by calculating the root mean square value. The data were analyzed by means of one-way analysis of variance to investigate the differences between the two groups. Paired t test was used to investigate the symmetry between the right and left sides. The significance level adopted was 0.05. RESULTS: The results showed that the individuals with scoliosis presented: (1 symmetrical neuromuscular activation between the sides; (2 lower neuromuscular efficiency; (3 greater capacity to resist fatigue; and (4 force values 42.6% lower than those of the individuals in the Control Group. CONCLUSIONS: The results suggest that surface EMG is an effective tool for functional assessments of scoliosis, although the protocol established limited the participation of individuals with scoliosis, from the perspective of neuromuscular efficiency.

E Bassani

2008-02-01

212

Avaliação da ativação neuromuscular em indivíduos com escoliose através da eletromiografia de superfície / Assessment of neuromuscular activation in individuals with scoliosis using surface electromyography  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: O objetivo desse estudo foi verificar o potencial da eletromiografia (EMG) de superfície para a avaliação da eficiência neuromuscular e da fadiga muscular localizada dos extensores lombares em indivíduos com escoliose. MÉTODOS: Participaram deste estudo 20 indivíduos divididos igualmente e [...] m dois grupos, (1) Grupo com Escoliose e (2) Grupo Controle, que foram submetidos a um teste de indução dos músculos extensores lombares a fadiga, o qual constituiu da realização de uma contração voluntária máxima isométrica (CVM), e realização de um teste com esforço a 80% da CVM. Foram coletados simultaneamente sinais de força e eletromiográficos (sinal EMG). O sinal EMG foi processado no domínio da freqüência, utilizando-se a transformada rápida de Fourier (FFT), por meio da mediana da freqüência (MF), e no domínio do tempo, pelo cálculo do valor root mean square (RMS). Os dados foram submetidos a uma análise de variância one-way para verificar as diferenças entre os dois grupos. Para verificar a simetria entre os lados direito e esquerdo, foi realizado o teste t pareado. O nível de significância adotado foi 0,05. RESULTADOS: os resultados demonstraram que indivíduos com escoliose apresentaram: (1) simetria de ativação neuromuscular entre os lados; (2) menor eficiência neuromuscular; (3) maior capacidade de resistir a fadiga; e (4) valores de força 42,6% menores que os indivíduos do GC. CONCLUSÕES: Os resultados sugerem que a EMG de superfície corresponde a um efetivo instrumento de avaliação funcional da escoliose, embora o protocolo estabelecido tenha limitado a participação dos indivíduos com escoliose, do ponto de vista da eficiência neuromuscular. Abstract in english OBJECTIVE: The aim of this study was to investigate the potential of surface electromyography (EMG) for assessing neuromuscular efficiency and localized muscle fatigue in the lumbar extensors, in individuals with scoliosis. METHODS: Twenty individuals participated in this study, divided equally into [...] two groups: (1) Scoliosis Group and (2) Control Group. These subjects underwent a fatigue induction test on their lumbar extensor muscles, consisting of one maximum voluntary isometric contraction (MVIC) followed by a test at 80% of the MVIC effort. Force and EMG signals were collected simultaneously. The EMG signal was processed in the frequency domain by means of fast Fourier transforms using the median frequency; and in the time domain by calculating the root mean square value. The data were analyzed by means of one-way analysis of variance to investigate the differences between the two groups. Paired t test was used to investigate the symmetry between the right and left sides. The significance level adopted was 0.05. RESULTS: The results showed that the individuals with scoliosis presented: (1) symmetrical neuromuscular activation between the sides; (2) lower neuromuscular efficiency; (3) greater capacity to resist fatigue; and (4) force values 42.6% lower than those of the individuals in the Control Group. CONCLUSIONS: The results suggest that surface EMG is an effective tool for functional assessments of scoliosis, although the protocol established limited the participation of individuals with scoliosis, from the perspective of neuromuscular efficiency.

E, Bassani; CT, Candotti; M, Pasini; M, Melo; M, La Torre.

2008-02-01

213

Neuromuscular Blockade with Rocuronium Bromide Increases the Tolerance of Acute Normovolemic Anemia in Anesthetized Pigs  

OpenAIRE

Background: The patient's individual anemia tolerance is pivotal when blood transfusions become necessary, but are not feasible for some reason. To date, the effects of neuromuscular blockade (NMB) on anemia tolerance have not been investigated. Methods: 14 anesthetized and mechanically ventilated pigs were randomly assigned to the Roc group (3.78 mg/kg rocuronium bromide followed by continuous infusion of 1 mg/kg/min, n = 7) or to the Sal group (administration of the corresponding volume of ...

Pape, A.; Kertscho, H.; Stein, P.; Lossen, M.; Horn, O.; Kutschker, S.; Zwissler, Bernhard; Habler, O.

2012-01-01

214

Distinct neural and neuromuscular strategies underlie independent evolution of simplified advertisement calls  

OpenAIRE

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 fro...

Leininger, Elizabeth C.; Kelley, Darcy B.

2013-01-01

215

Skeletal muscle fibrosis and stiffness increase after rotator cuff tendon injury and neuromuscular compromise in a rat model.  

Science.gov (United States)

Rotator cuff tears can cause irreversible changes (e.g., fibrosis) to the structure and function of the injured muscle(s). Fibrosis leads to increased muscle stiffness resulting in increased tension at the rotator cuff repair site. This tension influences repairability and healing potential in the clinical setting. However, the micro- and meso-scale structural and molecular sources of these whole-muscle mechanical changes are poorly understood. Here, single muscle fiber and fiber bundle passive mechanical testing was performed on rat supraspinatus and infraspinatus muscles with experimentally induced massive rotator cuff tears (Tenotomy) as well as massive tears with chemical denervation (Tenotomy + BTX) at 8 and 16 weeks post-injury. Titin molecular weight, collagen content, and myosin heavy chain profiles were measured and correlated with mechanical variables. Single fiber stiffness was not different between controls and experimental groups. However, fiber bundle stiffness was significantly increased at 8 weeks in the Tenotomy + BTX group compared to Tenotomy or control groups. Many of the changes were resolved by 16 weeks. Only fiber bundle passive mechanics was weakly correlated with collagen content. These data suggest that tendon injury with concomitant neuromuscular compromise results in extra-cellular matrix production and increases in stiffness of the muscle, potentially complicating subsequent attempts for surgical repair. PMID:24838823

Sato, Eugene J; Killian, Megan L; Choi, Anthony J; Lin, Evie; Esparza, Mary C; Galatz, Leesa M; Thomopoulos, Stavros; Ward, Samuel R

2014-09-01

216

Mechanisms for leaf control of gas exchange  

Energy Technology Data Exchange (ETDEWEB)

Several mechanisms enable leaf stomata to optimize water loss with respect to carbon gain. Stomatal responses to environmental variation constitute a plant's first and second lines of defense against damaging water deficits. Changes in the concentrations of endogenous growth regulations and their influence on stomata may well be important to both defense strategies.

Mansfield, T.A.; Davies, W.J.

1985-03-01

217

The controller design for kicker magnet adjustment mechanism in SSRF  

International Nuclear Information System (INIS)

The kicker magnet adjustment mechanism controller in SSRF is to improve the efficiency of injection by changing the magnet real-time, especially in the top-up mode. The controller mainly consists of Programmable logic controller (PLC), stepper motor, reducer, worm and mechanism. PLC controls the stepper motors for adjusting the azimuth of the magnet, monitors and regulates the magnet with tilt sensor. It also monitors the interlock. In addition, the controller is provided with local and remote working mode. This paper mainly introduces related hardware and software designs for this device. (authors)

218

Fuzzy Adaptive Sliding Mode Control of Large Erecting Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available Sincethe large erecting mechanism has nonlinearities, parameter uncertainties andexternal disturbance, it is difficult to realize a model-based sliding modecontrol design. So a fuzzy adaptive sliding mode control scheme which combinedfuzzy control with sliding mode control is proposed to achieve nonlinearcontrol of the erecting mechanism. This control scheme is mainly use the fuzzysystem to approximate the equivalent control of the sliding mode controllerwithout knowing the system dynamic model. And it also releases thetrial-and-error work of establishing the fuzzy inference rules. The update lawsfor the fuzzy tuning parameters and the switch control parameter are derivedbased on the Lyapunov stability analysis. The simulation results show that comparedto the PID control and conventional sliding mode control, the fuzzy adaptivesliding mode control has nicer robustness and more accurate tracking ability,and the stability of the erecting process has improved.

Li Liang

2013-07-01

219

Perioperative monitoring of neuromuscular transmission using acceleromyography prevents residual neuromuscular block following pancuronium.  

Science.gov (United States)

The frequency of postoperative residual neuromuscular block following the use of the long-acting non-depolarizing muscle relaxants is high, and manual evaluation of the response to nerve stimulation does not eliminate the problem. In this prospective and randomized study we evaluated the hypothesis that perioperative use of acceleromyography would allow for a more rational and precise administration of the long-acting muscle relaxant pancuronium resulting in a decrease in 1) the incidence and severity of postoperative residual neuromuscular block, 2) the amount of pancuronium used, and 3) the time from end of surgery to tracheal extubation. Forty adult patients were randomized into two groups, one managed without the use of a nerve stimulator, the other monitored using train-of-four (TOF) nerve stimulation and acceleromyography. All patients were anaesthetized with diazepam, fentanyl, thiopentone, nitrous oxide, and in some patients halothane, and they all received pancuronium 0.08-0.1 mg kg-1 for tracheal intubation, and 1-2 mg for maintenance of neuromuscular block. Neostigmine 2.5 mg preceded by atropine 1 mg was administered for reversal. In the patients managed without a nerve stimulator, the trachea was extubated when the anaesthetist judged the neuromuscular function to have recovered adequately for upper airway protection and spontaneous ventilation. In patients monitored with acceleromyography, the trachea was extubated when the TOF ratio was above 0.70. In all 40 patients, TOF ratio was measured using mechanomyography immediately after tracheal extubation and the patients were evaluated for clinical signs of residual neuromuscular block.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7484037

Mortensen, C R; Berg, H; el-Mahdy, A; Viby-Mogensen, J

1995-08-01

220

Molecular Mechanisms Controlling GLUT4 Intracellular Retention  

OpenAIRE

In basal adipocytes, glucose transporter 4 (GLUT4) is sequestered intracellularly by an insulin-reversible retention mechanism. Here, we analyze the roles of three GLUT4 trafficking motifs (FQQI, TELEY, and LL), providing molecular links between insulin signaling, cellular trafficking machinery, and the motifs in the specialized trafficking of GLUT4. Our results support a GLUT4 retention model that involves two linked intracellular cycles: one between endosomes and a retention compartment, an...

Blot, Vincent; Mcgraw, Timothy E.

2008-01-01

221

The genetic basis of neuromuscular disorders.  

Science.gov (United States)

In the last decade, our knowledge of human diseases genes has been growing rapidly as a result of the availability of resources and techniques for mapping and sequencing the human genome. New disease genes are now reported almost weekly. This review illustrates how the identification of genes involved in neuromuscular disorders has led to the characterization of not only novel genes, but also of a variety of different types of genetic mutation. These observations, which include high deletion frequencies, unstable tandem repeat sequences, genomic duplications and triplet repeat expansions, have facilitated the identification of similar types of mutation in other genetic disorders. PMID:8783938

Nawrotzki, R; Blake, D J; Davies, K E

1996-08-01

222

Cutaneous mechanisms of isometric ankle force control  

DEFF Research Database (Denmark)

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.

Choi, Julia T; Jensen, Jesper Lundbye

2013-01-01

223

The effects of neuromuscular electrical stimulation for dysphagia in opercular syndrome: a case study  

OpenAIRE

A 76-year-old man with opercular syndrome characterized by complete bilateral loss of voluntary control of facial, lingual, pharyngeal and masticatory muscles is presented with focus on the severe dysphagia. Three years earlier the patient had experienced two strokes resulting in opercular syndrome with severe dysphagia. Despite initial logopedic dysphagia treatment, swallowing did not improve. A new treatment for dysphagia, consisting of neuromuscular electrical stimulation was applied on th...

Baijens, Laura W. J.; Speyer, Rene?e; Roodenburg, Nel; Manni, Johannes J.

2008-01-01

224

Effect of Neuromuscular Electrical Stimulation on Pain and Functional Parameters in Knee Osteoarthritis  

OpenAIRE

Objective: To assess the effect of neuromuscular electrical stimulation (NMES) of quadriceps muscle on pain and functional level in knee osteoarthritis. Materials and Methods: Forty patients diagnosed as knee osteoarthritis participated in the study. Patients were randomized to two groups. First group received hotpack, ultrasound, transcutaneous electrical nerve stimulation (TENS) and isometric quadriceps exercises (control group), and second group received NMES of quadriceps muscle in additi...

Duygu Geler Külcü; Burcu Yan?k; Gülçin Gül?en Demirel; Derya Gökmen

2009-01-01

225

PGC-1? regulates the neuromuscular junction program and ameliorates Duchenne muscular dystrophy  

OpenAIRE

The coactivator PGC-1? mediates key responses of skeletal muscle to motor nerve activity. We show here that neuregulin-stimulated phosphorylation of PGC-1? and GA-binding protein (GABP) allows recruitment of PGC-1? to the GABP complex and enhances transcription of a broad neuromuscular junction gene program. Since a subset of genes controlled by PGC-1? and GABP is dysregulated in Duchenne muscular dystrophy (DMD), we examined the effects of transgenic PGC-1? in muscle of mdx mice. These ...

Handschin, Christoph; Kobayashi, Yvonne M.; Chin, Sherry; Seale, Patrick; Campbell, Kevin P.; Spiegelman, Bruce M.

2007-01-01

226

Neuromuscular manifestations in hereditary haemochromatosis.  

Science.gov (United States)

Involvement of peripheral nerves and skeletal muscles has been reported in the course of hereditary haemochromatosis (HH) but a systematic study is lacking. However, patients with HH report symptoms suggesting a possible polyneuropathy or myopathy. In this study patients with DNA proven HH were recruited from a large general teaching hospital. First, all patients were clinically examined using a structured interview and neurological exam. After reviewing these data an expert panel reached consensus about the presence of a possible neuropathy or myopathy and made recommendations for ancillary investigations (nerve conduction studies, electromyography, thermal threshold tests, laboratory tests). After a second meeting consensus was reached about the final diagnosis. Patients who had a neuropathy or myopathy of which the origin was still unclear were referred to an independent neurologist for further evaluation. Ultimately, of 46 patients included, 25 had no myopathy or neuropathy, 5 an axonal sensory motor polyneuropathy of which the cause was found (diabetes in 2, combination of diabetes and chemotherapy in 1, Charcot Marie Tooth type 2 in 1, Morbus Sjögren in 1), 9 an idiopathic axonal sensory motor polyneuropathy, 3 an idiopathic small fiber polyneuropathy and 4 a carpal tunnel syndrome. There were no cases of proven myopathy. We conclude that an idiopathic polyneuropathy was diagnosed in a relative large number of patients with HH (26%), but the causal relationship needs to be confirmed in larger (case-control) series. PMID:20358215

Wouthuis, S F; van Deursen, C Th B M; te Lintelo, M P; Rozeman, C A M; Beekman, R

2010-09-01

227

Gain control mechanisms in spinal motoneurons  

OpenAIRE

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...

Michael David Johnson; Cj, Heckman

2014-01-01

228

Relation of quantum control mechanism to landscape structure  

Science.gov (United States)

The control of quantum dynamics is generally accomplished by seeking a tailored electromagnetic field to meet a posed objective. A particular shaped field can be thought of as specifying a point on a quantum control landscape, which is the objective as a functional of the controls. Optimizing the pulse shape corresponds to climbing the landscape, and previous work showed that the paths taken up the landscapes, guided by a gradient algorithm, are surprisingly straight when projected into the space of control fields. The direct nature of these control trajectories can be quantified by the metric R ?1, defined as the ratio of the length of the control trajectory to the Euclidean distance between its end points. The prior observation of often finding low values of R implies that the landscapes are structurally simple. In this work, we investigate whether there is a relationship between the intricacy of the control mechanism and the complexity of the trajectory taken through the control space reflected in the value of R. We use the Hamiltonian encoding procedure to identify the mechanism, and we examine control of the state-to-state transition probability. No significant correlation is found between the landscape structure, reflected in the value of R, and the control mechanism. This result has algorithmic implications, opening up the prospect of seeking fields producing particular mechanisms at little penalty in the search effort due to encountering complex landscape structure.

Nanduri, Arun; Donovan, Ashley; Ho, Tak-San; Rabitz, Herschel

2014-07-01

229

Method of Automatically exchanging control rod drive mechanisms  

International Nuclear Information System (INIS)

Purpose: To automatically smoothly executing a CRD exchanging work for short time by comparing the target value of a control rod drive mechanism (CRD) with the present position of a CRD exchanging device, thereby controlling the CRD exchanging device by using a computer. Method: The respective positions of a control rod drive mechanism are stored beforehand as target values, when the exchange of the CRD is necessary, the target value of the CRD to be exchanged is unloaded, the present position of the CRD is compared with the target value, and the CRD exchanging device is controlled on the basis of the deviation value. (Kamimura, M.)

230

Diagnosis of Neuromuscular Disorders Using Softcomputing Techniques  

Directory of Open Access Journals (Sweden)

Full Text Available Biomedical signals are collection of electrical signals which generated from any organ that signal represents a physical variable of interest. Electromyography (EMG is a technique for evaluating and recording of electrical activities produced from skeletal muscles. There are so many applications of EMG signals. Major interests lies in the field of clinical as well as biomedical engineering.EMG is used as a diagnostic tool for identifying neuromuscular disorders .Motor unit action potentials (MUPS provides information about neuromuscular disorders. Traditionally neurophysiologist can access MUPs information from their shapes and patterns using an oscilloscope. But MUPs from different motor neurons will overlap leads to the formation of interference pattern and it is difficult to detect individual shapes accurately. For this reason a number of computer based quantitative EMG analysis algorithm have been developed. In this work, different types of learning methods were used to classify EMG signals. The model automatically classifies EMG signals into normal, myopathy and neuropathy. In order to extract useful information from the EMG signals different feature extraction methods such as discrete wavelet transform(DWT and auto regressive modeling(ARare implemented. Adaptive neuro-fuzzy inference system (ANFIS with hybrid learning algorithm, support vector machine (SVM and fuzzy support vector machine (FSVM were compared in relation to their accuracy in the classification of EMG signals. Based on the impacts of features on the EMG signal classification, different results were obtained through analysis of the soft computing techniques.

Akhila Devi.B.V

2013-11-01

231

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

DEFF Research Database (Denmark)

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 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-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-activity 50ms prior to toe-down than males (P

Bencke, Jesper; Zebis, Mette K

2011-01-01

232

Dynamic Discontinuous Control for Active Control of Mechanical Vibrations Control discontinuo dinámico para control activo de vibraciones mecánicas  

OpenAIRE

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 suspensi...

Alberto Prieto Moreno; Orestes Llanes Santiago

2010-01-01

233

Novel Mechanism Control Algorithm for Wired Network  

Directory of Open Access Journals (Sweden)

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.

V. B. Kirubanand

2011-01-01

234

Molecular motors: design, mechanism and control  

CERN Document Server

Biological functions in each animal cell depend on coordinated operations of a wide variety of molecular motors. Some of the these motors transport cargo to their respective destinations whereas some others are mobile workshops which synthesize macromolecules while moving on their tracks. Some other motors are designed to function as packers and movers. All these motors require input energy for performing their mechanical works and operate under conditions far from thermodynamic equilibrium. The typical size of these motors and the forces they generate are of the order of nano-meters and pico-Newtons, respectively. They are subjected to random bombardments by the molecules of the surrounding aqueous medium and, therefore, follow noisy trajectories. Because of their small inertia, their movements in the viscous intracellular space exhibits features that are characteristics of hydrodynamics at low Reynold's number. In this article we discuss how theoretical modeling and computer simulations of these machines by...

Chowdhury, Debashish

2007-01-01

235

Control Loop Feedback Mechanism for Generic Array Logic Chip Multiprocessor  

OpenAIRE

Control Loop Feedback Mechanism for Generic Array Logic Chip Multiprocessor is presented. The approach is based on control-loop feedback mechanism to maximize the efficiency on exploiting available resources such as CPU time, operating frequency, etc. Each Processing Element (PE) in the architecture is equipped with a frequency scaling module responsible for tuning the frequency of processors at run-time according to the application requirements. We show that generic array l...

Vijayalakshmi, V. Karthikeyan V. J.

2014-01-01

236

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

Science.gov (United States)

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 30min of NMES (25Hz, 800ms on/800ms 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). PMID:25434572

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

2014-11-01

237

Consecuencias clínicas de las alteraciones neuromusculares en el paciente crítico / Clinical consequences of neuromuscular impairments in critically ill patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish La patología neuromuscular en el paciente crítico se desarrolla en dos contextos: enfermedades neurológicas primarias que requieren su ingreso en Medicina Intensiva por necesitar vigilancia estricta o ventilación mecánica y manifestaciones del sistema nervioso periférico secundarias a enfermedades s [...] istémicas críticas. En el primer grupo son las más frecuentes el Síndrome de Guillain-Barré y la Miastenia Gravis y en el segundo la Polineuropatía y la Miopatía del paciente crítico. El patrón clínico común más frecuente consiste en el desarrollo de un cuadro de acusada debilidad y cuadriparesia cuya manifestación más típica es la necesidad de respiración asistida o la dificultad/imposibilidad para su retirada. Se consideran factores desencadenantes el fracaso multiorgánico y la sepsis en la polineuropatía y los esteroides y bloqueantes neuromusculares en la miopatía, actuando como coadyuvantes en ambos casos la malnutrición, particularmente la hipoalbimunemia, y la hiperglucemia. Considerando que la afectación neuropática y miopática coexisten con frecuencia, se ha acuñado el término polineuromiopatía del paciente crítico. Tanto el Síndrome de Guillain-Barré como la polineuropatía del paciente crítico se localizan a nivel del nervio periférico, por lo que debe efectuarse un diagnóstico diferencial entre ambos. La forma de presentación es diferente ya que el primero es una patología aguda que motiva su ingreso en UCI, mientras que la polineuropatía se adquiere durante la hospitalización. En el primero es frecuente la afectación del sistema nervioso autónomo y la disociación albúmino-citológica en el LCR, lo que no se da en la polineuropatía. Los estudios electrofisiológicos muestran signos de desmelinización con disminución de la velocidad de conducción y normalidad en la amplitud de potenciales motores en el Síndrome de Guillain- Barré frente a velocidad de conducción normal y amplitud reducida de potenciales motores en la polineuropatía axonal. La crisis miasténica afecta a la unión neuromuscular y su diagnóstico suele ser más fácil al tener en la mayoría de los casos un diagnóstico previo de miastenia gravis.La debilidad muscular aumenta durante la actividad repetida (fatiga muscular) y mejora con el reposo. Su confirmación diagnóstica se realiza con el test del edofronio y con la estimulación nerviosa repetitiva, que provoca una rápida disminución del 10-15% en la amplitud de las respuestas provocadas. La miopatía del paciente crítico se localiza en el músculo y provoca una debilidad generalizada con cuadriparesia, muy similar a la de la polineuropatía, que impide o retrasa la desconexión de la ventilación mecánica y que en sus grados avanzados puede provocar un aumento de CPK y mioglobina, junto con alteraciones en la exploración neurofisiológica. Esta última es difícil de discernir de la encontrada en la polineuropatía, aunque la normalidad en los potenciales de acción sensitiva y la redución en el potencial de ación motora con estimulación muscular directa, puede ayudar a diferenciarlos. El pronóstico funcional de las alteraciones musculares primarias suele ser bastante bueno, pero tanto la polineuropatía como la miopatía evolucionan lentamente a lo largo de semanas o meses, pudiendo quedar un importante déficit residual a los dos años en los casos más graves. Abstract in english Neuromuscular pathology in the critically ill patient develops within two settings: primary neurological diseases that require admission in the Intensive Care Medicine Unit for close monitoring or mechanical ventilation, and peripheral nervous system manifestations secondary to critical systemic dis [...] eases. The most frequent conditions in the first group are Guillain-Barré syndrome and Myasthenia Gravis, and in the second group, polyneuropathy and myopathy of the critically ill patient. The most commonly shared clinical pattern is the development of severe weakness and

A., Mesejo; E., Pérez-Sancho; E., Moreno.

2006-05-01

238

Insuficiência respiratória crônica nas doenças neuromusculares: diagnóstico e tratamento Chronic respiratory failure in patients with neuromuscular diseases: diagnosis and treatment  

Directory of Open Access Journals (Sweden)

Full Text Available As doenças neuromusculares prejudicam a renovação do ar alveolar e, por esta razão, produzem insuficiência respiratória crônica. A instalação da insuficiência respiratória pode acontecer de modo agudo, como nos traumas, ou ser lenta ou rapidamente progressiva, como na esclerose lateral amiotrófica, distrofias musculares, doença da placa mioneural, etc. O comprometimento da musculatura respiratória prejudica também a eficiência da tosse e, no estado atual da terapêutica disponível no Brasil para estes doentes, pode-se dizer que a morbimortalidade nestes indivíduos está mais associada ao fato de que eles tossem mal do que de que ventilam mal. Nesta revisão, uma breve compilação histórica procura mostrar a evolução das órteses e próteses respiratórias, desde o final do século XIX até agora, com o objetivo de apresentar as opções de máquinas disponíveis para o suporte e substituição da ventilação nas doenças neuromusculares. Além disso, são enfatizados os elementos fundamentais para o diagnóstico da hipoventilação alveolar e da falência do mecanismo protetor da tosse: história clínica, determinação do pico de fluxo da tosse, medida da pressão expiratória máxima e da pressão inspiratória máxima, espirometria em dois decúbitos (sentado e supino, oximetria de pulso, capnografia e polissonografia. São apresentados os valores limites disponíveis na literatura tanto para a indicação do suporte noturno da ventilação como para a extensão do suporte para o período diurno. As manobras para incremento da eficiência da tosse são aqui também discutidas, assim como o momento adequado para sua introdução.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.

Ilma Aparecida Paschoal

2007-02-01

239

Insuficiência respiratória crônica nas doenças neuromusculares: diagnóstico e tratamento / Chronic respiratory failure in patients with neuromuscular diseases: diagnosis and treatment  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese As doenças neuromusculares prejudicam a renovação do ar alveolar e, por esta razão, produzem insuficiência respiratória crônica. A instalação da insuficiência respiratória pode acontecer de modo agudo, como nos traumas, ou ser lenta ou rapidamente progressiva, como na esclerose lateral amiotrófica, [...] distrofias musculares, doença da placa mioneural, etc. O comprometimento da musculatura respiratória prejudica também a eficiência da tosse e, no estado atual da terapêutica disponível no Brasil para estes doentes, pode-se dizer que a morbimortalidade nestes indivíduos está mais associada ao fato de que eles tossem mal do que de que ventilam mal. Nesta revisão, uma breve compilação histórica procura mostrar a evolução das órteses e próteses respiratórias, desde o final do século XIX até agora, com o objetivo de apresentar as opções de máquinas disponíveis para o suporte e substituição da ventilação nas doenças neuromusculares. Além disso, são enfatizados os elementos fundamentais para o diagnóstico da hipoventilação alveolar e da falência do mecanismo protetor da tosse: história clínica, determinação do pico de fluxo da tosse, medida da pressão expiratória máxima e da pressão inspiratória máxima, espirometria em dois decúbitos (sentado e supino), oximetria de pulso, capnografia e polissonografia. São apresentados os valores limites disponíveis na literatura tanto para a indicação do suporte noturno da ventilação como para a extensão do suporte para o período diurno. As manobras para incremento da eficiência da tosse são aqui também discutidas, assim como o momento adequado para sua introdução. Abstract in english 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. Respi [...] ratory 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.

Ilma Aparecida, Paschoal; Wander de Oliveira, Villalba; Mônica Corso, Pereira.

2007-02-01

240

Neuromuscular blockade in cardiac surgery: An update for clinicians  

Directory of Open Access Journals (Sweden)

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.

Hemmerling Thomas

2008-01-01

241

?????????????????? Brown Adipose Tissue Differentiation and Control Mechanism  

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Full Text Available ?????????????????????????(???????????????????????????????????????????????????????????????????????????????BMP7 (bone morphogenetic proteins 7???????-??????(transforming growth?TGF-?????????????????????????????????????????????????????????BMP7??????????????????BMP7??PRDM16?PGC-1??????????????UCP1????????????????????????????????????????????? BMP7?PRDM16 ?????????????????????????????????????????????????–???????????????(?X-????????(18F-FDG-PET/CT????????????????????????????????????????????????????????????????????Humans and other mammals have two main adipose tissue depots: white adipose tissue (include visceral- and subcutaneous- white adipose tissue, and brown adipose tissue, each of which possesses unique cell-autonomous properties. In contrast to visceral adipose tissue, which can induce detrimental metabolic ef-fects, subcutaneous white adipose tissue and brown adipose tissue have the potential to benefit metabolism by improving glucose homeostasis and increasing energy consumption. BMP7 (bone morphogenetic proteins7 is one of members of the transforming growth factor-? (TGF-? superfamily and control multiple key steps of embryonic development and differentiation. In recent studies, people found that BMP7-induced UCP1 ex-pression was markedly diminished in brown preadipocytes deficient in both PRDM16 and PGC (PGC-1? and PGC-1?, it ultimately induces BAT mitochondrial cells in the biological production and cell differentiation. There are two ways in development of brown adipose tissue. These researches indicate the potential to treat obesity and related diseases through activating BMP7 and PRDM16 to produce brown adipose tissue. Re-cently, using 18F-fluorodeoxyglucose (18F-FDG positron-emission tomographic and computed tomographic (PET-CT scans showed that adults retain metabolically active BAT depots that can be induced in response to cold and sympathetic nervous system activation. These findings high light BAT as a potenial relevant tar get for pharmacological and gene expression manipulation to combat human obesity. We reviewed the recent re-search progresses of BAT in human and its potential functional significance.

???

2011-12-01

242

Ação neuro-muscular do veneno crotálico: dados preliminares / Neuromuscular action of crotalid venom: preliminar data  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 pe [...] riférico 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 admite que veneno crotálico determina síndrome miastênica. Nossos achados indicam que ptose palpebral, facies miastênico e fraqueza muscular observados após acidente crotálico, correspondem provavelmente a miopatia mitocondrial, muitas vezes transitória e reversível. Abstract in english We studied 6 patients and 2 dogs that have been bitten by South American rattlesnake Crotalus durissus terrificus and one rabbit inoculated with crotalid venom. We analized sensory and motor peripheral nerve conduction, repetitive stimulation for studying neuromuscular transmission and electromyogra [...] phies. Muscle biopsies were processed by histochemistry. All patients had peripheral mononeuropathy of the closest sensitive nerve to the area of snakebite. The neuromuscular transmission alterations were minimal. Muscle histochemistry of 4 patients, 2 dogs and 1 rabbit showed findings of mitochondrial myopathy. The majority of authors admit that crotalid venom causes myastenic syndrome. Our findings suggest that palpebral ptosis, myastenic facies and muscular weakness observed after crotalid poisoning are, probably, due to transient and reversible mitochondrial myopathy. As far as we know, this is the first report on the ability of the venom of this rattlesnake to cause local sensitive mononeuropathy and the first muscle histochemistry showing mitochondrial myopathy in humans poisoned by crotalid venom.

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

1996-03-01

243

Anormalidades neuromuscular no desuso, senilidade e caquexia Neuromuscular abnormalities in disuse, cachexia and ageing  

OpenAIRE

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 trófi...

João Aris Kouyoumdjian

1993-01-01

244

Ação neuro-muscular do veneno crotálico: dados preliminares Neuromuscular action of crotalid venom: preliminar data  

Directory of Open Access Journals (Sweden)

Full Text Available 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 admite que veneno crotálico determina síndrome miastênica. Nossos achados indicam que ptose palpebral, facies miastênico e fraqueza muscular observados após acidente crotálico, correspondem provavelmente a miopatia mitocondrial, muitas vezes transitória e reversível.We studied 6 patients and 2 dogs that have been bitten by South American rattlesnake Crotalus durissus terrificus and one rabbit inoculated with crotalid venom. We analized sensory and motor peripheral nerve conduction, repetitive stimulation for studying neuromuscular transmission and electromyographies. Muscle biopsies were processed by histochemistry. All patients had peripheral mononeuropathy of the closest sensitive nerve to the area of snakebite. The neuromuscular transmission alterations were minimal. Muscle histochemistry of 4 patients, 2 dogs and 1 rabbit showed findings of mitochondrial myopathy. The majority of authors admit that crotalid venom causes myastenic syndrome. Our findings suggest that palpebral ptosis, myastenic facies and muscular weakness observed after crotalid poisoning are, probably, due to transient and reversible mitochondrial myopathy. As far as we know, this is the first report on the ability of the venom of this rattlesnake to cause local sensitive mononeuropathy and the first muscle histochemistry showing mitochondrial myopathy in humans poisoned by crotalid venom.

Maria Dorvalina Silva

1996-03-01

245

Soft Time-Suboptimal Controlling Structure for Mechanical Systems  

DEFF Research Database (Denmark)

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, with uncertain (also non-stationary) mass treated as a stochastic process. The methodology proposed here is of a universal nature and may easily be applied with respect to other uncertainty elements of timeoptimal controlled mechanical systems.

Kulczycki, Piotr; Wisniewski, Rafal

2004-01-01

246

Sliding mode control on electro-mechanical systems  

OpenAIRE

The first sliding mode control application may be found in the papers back in the 1930s in Russia. With its versatile yet simple design procedure the methodology is proven to be one of the most powerful solutions for many practical control designs. For the sake of demonstration this paper is oriented towards application aspects of sliding mode control methodology. First the design approach based on the regularization is generalized for mechanical systems. It is shown that stability of zero...

Utkin, Vadim I.; Hao-Chi Chang

2002-01-01

247

Neuromuscular ultrasound findings in polyneuropathy secondary to disulfiram.  

Science.gov (United States)

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. PMID:25462150

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

2014-12-01

248

TrkB kinase activity maintains synaptic function and structural integrity at adult neuromuscular junctions.  

Science.gov (United States)

Activation of the tropomyosin-related kinase receptor B (TrkB) by brain-derived neurotrophic factor acutely regulates synaptic transmission at adult neuromuscular junctions (NMJs). The role of TrkB kinase activity in the maintenance of NMJ function and structure at diaphragm muscle NMJs was explored using a chemical-genetic approach that permits reversible inactivation of TrkB kinase activity in TrkB(F616A) mice by 1NMPP1. Inhibiting TrkB kinase activity for 7 days resulted in significant, yet reversible, impairments in neuromuscular transmission at diaphragm NMJs. Neuromuscular transmission failure following 2 min of repetitive phrenic nerve stimulation increased from 42% in control to 59% in 1NMPP1-treated TrkB(F616A) mice (P = 0.010). Recovery of TrkB kinase activity following withdrawal of 1NMPP1 treatment improved neuromuscular transmission (P = 0.006). Electrophysiological measurements at individual diaphragm NMJs documented lack of differences in quantal content in control and 1NMPP1-treated mice (P = 0.845). Morphological changes at diaphragm NMJs were modest following inhibition and recovery of TrkB kinase activity. Three-dimensional reconstructions of diaphragm NMJs revealed no differences in volume at motor end plates (labeled by ?-bungarotoxin; P = 0.982) or presynaptic terminals (labeled by synaptophysin; P = 0.515). Inhibition of TrkB kinase activity by 1NMPP1 resulted in more compact NMJs, with increased apposition of presynaptic terminals and motor end plates (P = 0.017) and reduced fragmentation of motor end plates (P = 0.005). Recovery of TrkB kinase activity following withdrawal of 1NMPP1 treatment resulted in postsynaptic remodeling likely reflecting increased gutter depth (P = 0.007), without significant presynaptic changes. These results support an essential role for TrkB kinase activity in maintaining synaptic function and structural integrity at NMJs in the adult mouse diaphragm muscle. PMID:25170066

Mantilla, Carlos B; Stowe, Jessica M; Sieck, Dylan C; Ermilov, Leonid G; Greising, Sarah M; Zhang, Chao; Shokat, Kevan M; Sieck, Gary C

2014-10-15

249

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)

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 other hand showed that this effect may arise without any anticipatory neural control mechanism. PMID:25393548

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

2014-11-01

250

Influência de anestésicos locais sobre o bloqueio neuromuscular produzido pelo rocurônio: ação da lidocaína e da mistura enantiomérica em excesso de 50% de bupivacaína na junção neuromuscular Influencia de anestésicos locales sobre el bloqueo neuromuscular producido por el rocuronio: acción de la lidocaína y de la mezcla enantiomérica en exceso de 50% de bupivacaína en la junción neuromuscular Influence of local anesthetics on the neuromuscular blockade produced by rocuronium: effects of lidocaine and 50% enantiomeric excess bupivacaine on the neuromuscular junction  

OpenAIRE

JUSTIFICATIVA E OBJETIVOS: Os efeitos dos anestésicos locais (AL) na transmissão neuromuscular e sua influência no bloqueio neuromuscular produzido por bloqueadores neuromusculares competitivos são ainda alvo de pouca investigação. O objetivo do estudo foi avaliar in vitro os efeitos da lidocaína e da mistura enantiomérica em excesso de 50% de bupivacaína (S75-R25) no bloqueio neuromuscular produzido pelo rocurônio. MÉTODOS: Ratos foram distribuídos em cinco grupos (n = 5) de acor...

Angélica de Fátima de Assunção Braga; Vanessa Henriques Carvalho; Franklin Sarmento da Silva Braga; Léa Rodrigues-Simioni; Loyola, Yolanda Christina S.; Glória Braga Potério

2009-01-01

251

Acceleration of neuromuscular re-innervation by triiodothyronine.  

Science.gov (United States)

The right sciatic nerve was crushed in 84 rats, 42 of which were injected daily with triiodothyronine (T3; 1-0 mug/kg body weight, subcutaneously) while the others served as untreated controls. Rats in both groups were killed in groups of 6 at intervals of 5 days and the re-innervation of the tibialis anterior muscle was examined histologically using the bromoindigo-silver method. Neuromuscular re-innervation was first apparent 15 days post-operatively and was largely complete by the 35th day in the T3-treated group. In the untreated control animals only two thirds of the end-plates were innervated after 35 days. The argyrophilic remains of degenerated axons disappeared more quickly in rats treated with T3, and degenerative changes in the structure of the subneural apparatus were less severe in these animals than in the controls. It is suggested that consideration be given to the possibility of using exogenous T3 in the clinical management of human peripheral nerve injuries. PMID:1213954

McIsaac, G; Kiernan, J A

1975-12-01

252

Resistance to nondepolarizing neuromuscular blocking agents.  

Science.gov (United States)

Several case reports of resistance to short-term administration of nondepolarizing neuromuscular blocking agents (NNMBAs) have been reported in research and surgical settings. Recently, several reports documented resistance to NNMBAs during therapy for prolonged paralysis in critically ill patients. Adverse outcomes associated with NNMBA resistance may include inadequate ventilatory management or suppression of patient movement, and an increased risk of dose-dependent cardiovascular adverse effects. Pharmacoeconomic issues must be considered in that the cost of NNMBA therapy in a resistant patient may be significant. Although the specific etiologies of resistance are not clear, several pharmacodynamic and pharmacokinetic alterations may occur as a consequence of disease state or concomitant drug therapy. Pharmacodynamic changes include altered acetylcholine receptor physiology or sensitivity, inhibition of serum cholinesterase activity, and interaction with plasma constituents. Alterations in distribution volume, protein binding, and clearance may also contribute to resistance in several disease states. PMID:8726599

Tschida, S J; Graupe, K J; Hoey, L L; Vance-Bryan, K

1996-01-01

253

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

Directory of Open Access Journals (Sweden)

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.

Qiu Xinping

2010-03-01

254

Plastin 3 ameliorates spinal muscular atrophy via delayed axon pruning and improves neuromuscular junction functionality.  

Science.gov (United States)

F-actin bundling plastin 3 (PLS3) is a fully protective modifier of the neuromuscular disease spinal muscular atrophy (SMA), the most common genetic cause of infant death. The generation of a conditional PLS3-over-expressing mouse and its breeding into an SMA background allowed us to decipher the exact biological mechanism underlying PLS3-mediated SMA protection. We show that PLS3 is a key regulator that restores main processes depending on actin dynamics in SMA motor neurons (MNs). MN soma size significantly increased and a higher number of afferent proprioceptive inputs were counted in SMAPLS3 compared with SMA mice. PLS3 increased presynaptic F-actin amount, rescued synaptic vesicle and active zones content, restored the organization of readily releasable pool of vesicles and increased the quantal content of the neuromuscular junctions (NMJs). Most remarkably, PLS3 over-expression led to a stabilization of axons which, in turn, resulted in a significant delay of axon pruning, counteracting poor axonal connectivity at SMA NMJs. These findings together with the observation of increased endplate and muscle fiber size upon MN-specific PLS3 over-expression suggest that PLS3 significantly improves neuromuscular transmission. Indeed, ubiquitous over-expression moderately improved survival and motor function in SMA mice. As PLS3 seems to act independently of Smn, PLS3 might be a potential therapeutic target not only in SMA but also in other MN diseases. PMID:23263861

Ackermann, Bastian; Kröber, Sandra; Torres-Benito, Laura; Borgmann, Anke; Peters, Miriam; Hosseini Barkooie, Seyyed Mohsen; Tejero, Rocio; Jakubik, Miriam; Schreml, Julia; Milbradt, Janine; Wunderlich, Thomas F; Riessland, Markus; Tabares, Lucia; Wirth, Brunhilde

2013-04-01

255

Teaching Visually Impaired Adults with a Neuromuscular Disorder.  

Science.gov (United States)

The effects of four neuromuscular disorders (stroke, Parkinson's disease, Huntington's disease, and Lou Gehrig's disease) on concommitant visual impairments are considered. Rehabilitation approaches and equipment that help clients cope with the condition are described. (CL)

Williams, Susan

1983-01-01

256

A functional system for high-content screening of neuromuscular junctions in vitro.  

Science.gov (United States)

High-content phenotypic screening systems are the logical extension of the current efficient, yet low information content, pre-clinical screens for drug discovery. A physiologically accurate in vitro neuromuscular junction (NMJ) screening system would therefore be of tremendous benefit to the study of peripheral neuropathies as well as for basic and applied neuromuscular research. To date, no fully-defined, selective assay system has been developed which would allow investigators to determine the functional output of cultured muscle fibers (myotubes) when stimulated via the NMJ in real time for both acute and chronic applications. Here we present the development of such a phenotypic screening model, along with evidence of NMJ formation and motoneuron initiated neuromuscular transmission in an automated system. Myotubes assembled on silicon cantilevers allowed for measurement of substrate deflection in response to contraction and provided the basis for monitoring the effect of controlled motoneuron stimulation on the contractile behavior. The effect was blocked by treatment with D-tubocurarine, confirming NMJ functionality in this highly multiplexed assay system. PMID:25019094

Smith, A S T; Long, C J; Pirozzi, K; Hickman, J J

2013-01-01

257

Mechanisms for control of biological electron transfer reactions.  

Science.gov (United States)

Electron transfer (ET) through and between proteins is a fundamental biological process. The rates and mechanisms of these ET reactions are controlled by the proteins in which the redox centers that donate and accept electrons reside. The protein influences the magnitudes of the ET parameters, the electronic coupling and reorganization energy that are associated with the ET reaction. The protein can regulate the rates of the ET reaction by requiring reaction steps to optimize the system for ET, leading to kinetic mechanisms of gated or coupled ET. Amino acid residues in the segment of the protein through which long range ET occurs can also modulate the ET rate by serving as staging points for hopping mechanisms of ET. Specific examples are presented to illustrate these mechanisms by which proteins control rates of ET reactions. PMID:25085775

Williamson, Heather R; Dow, Brian A; Davidson, Victor L

2014-12-01

258

Rock mechanics. Superplastic nanofibrous slip zones control seismogenic fault friction.  

Science.gov (United States)

Understanding the internal mechanisms controlling fault friction is crucial for understanding seismogenic slip on active faults. Displacement in such fault zones is frequently localized on highly reflective (mirrorlike) slip surfaces, coated with thin films of nanogranular fault rock. We show that mirror-slip surfaces developed in experimentally simulated calcite faults consist of aligned nanogranular chains or fibers that are ductile at room conditions. These microstructures and associated frictional data suggest a fault-slip mechanism resembling classical Ashby-Verrall superplasticity, capable of producing unstable fault slip. Diffusive mass transfer in nanocrystalline calcite gouge is shown to be fast enough for this mechanism to control seismogenesis in limestone terrains. With nanogranular fault surfaces becoming increasingly recognized in crustal faults, the proposed mechanism may be generally relevant to crustal seismogenesis. PMID:25504714

Verberne, Berend A; Plümper, Oliver; de Winter, D A Matthijs; Spiers, Christopher J

2014-12-12

259

Molecular Mechanisms Controlling the Early Mouse Embryo Development  

Directory of Open Access Journals (Sweden)

Full Text Available Few are known about the molecular mechanism controlling the early embryo development. The reduce dimension of the embryos, only a few ?m, the small quantities of proteins synthesized and the artificial environment influence makes difficult to decode the mechanisms controlling early embryonic stages of development. Although, in the last few years many genes have been showed to be active in the early embryonic stages of development, only a few have been characterized and found to be implicated in the molecular mechanism responsible of preimplantational embryos development. Ped gene (Preimplantational embryo development is considered to be involved in regulation of embryonic cleavage division and subsequent embryo survival. This review presents, based on a rich documentation, the main mechanisms involved in early embryo development.

Alexandra Ivan

2010-05-01

260

Neuromuscular blockade in cardiac surgery: An update for clinicians  

OpenAIRE

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 i...

Hemmerling Thomas; Russo Gianluca; Bracco David

2008-01-01

261

Quality of life after surgery for neuromuscular scoliosis  

OpenAIRE

Surgery in patients with neuromuscular scoliosis is associated with a higher rate of complications. It is still controversially discussed whether the patients truly benefit from deformity correction. The purpose of this study is to investigate if the quality of life has been improved and if the patients and their caregivers are satisfied with the results of surgery. This is a retrospective clinical outcome study of 46 patients with neuromuscular scoliosis which were treated with primary stabl...

Thomas Niemeyer; Andrea Bevot; Almut Goll; Nikolaus Wülker; Corinna Leichtle; Peter Obid

2013-01-01

262

Formation of neuromuscular junctions in rat embryo cell cultures  

International Nuclear Information System (INIS)

The morphological evidence of the primary nerve muscle contacts are described. They consist of areas of cholinesterase activity (detected histochemically) localized on the myotube membranes and of multiple clusters of ACh receptors whose 125I-?-bungarotoxin binding sites are revealed by radioautography. After the stage of the primary nerve muscle contacts, some of which seem transient, characteristic neuromuscular junctions appear. These neuromuscular junctions which possess subneural infoldings are similar to the end-plates of the rat in vivo

263

Optimal piezo-electro-mechanical coupling to control plate vibrations  

OpenAIRE

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-Lo...

Alessandroni, Silvio; Isola, Francesco; Frezza, Fabrizio

2010-01-01

264

Mechanical design and optimal control of humanoid robot (TPinokio)  

OpenAIRE

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...

Teck Chew Wee

2014-01-01

265

Mechanical Tension Controls Granulation Tissue Contractile Activity and Myofibroblast Differentiation  

OpenAIRE

We have examined the role of mechanical tension in myofibroblast differentiation using two in vivo rat models. In the first model, granulation tissue was subjected to an increase in mechanical tension by splinting a full-thickness wound with a plastic frame. Myofibroblast features, such as stress fiber formation, expression of ED-A fibronectin and ?-smooth muscle actin (?-SMA) appeared earlier in splinted than in unsplinted wounds. Myofibroblast marker expression decreased in control wounds...

Hinz, Boris; Mastrangelo, Dominique; Iselin, Christophe E.; Chaponnier, Christine; Gabbiani, Giulio

2001-01-01

266

Dynamics and control of mechanical systems in offshore engineering  

CERN Document Server

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:                                                                                                                                 ...

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

2014-01-01

267

Combination of the Sorting Line Priority Polling Control Mechanism  

Directory of Open Access Journals (Sweden)

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

Wenxue Ran

2013-10-01

268

Squeezing of mechanical motion via qubit-assisted control  

Science.gov (United States)

We propose a feedback control mechanism for the squeezing of the phononic mode of a mechanical oscillator. We show how, under appropriate working conditions, a simple adiabatic approach is able to induce mechanical squeezing. We then go beyond the limitations of such a working point and demonstrate the stationary squeezing induced by using repeated measurements and reinitialization of the state of a two-level system ancilla coupled to the oscillator. Our nonadaptive feedback loop offers interesting possibilities for quantum state engineering and steering in open-system scenarios.

Genoni, Marco G.; Bina, Matteo; Olivares, Stefano; De Chiara, Gabriele; Paternostro, Mauro

2015-01-01

269

Flexible neural mechanisms of cognitive control within human prefrontal cortex  

OpenAIRE

A major challenge in research on executive control is to reveal its functional decomposition into underlying neural mechanisms. A typical assumption is that this decomposition occurs solely through anatomically based dissociations. Here we tested an alternative hypothesis that different cognitive control processes may be implemented within the same brain regions, with fractionation and dissociation occurring on the basis of temporal dynamics. Regions within lateral prefrontal cortex (PFC) wer...

Braver, Todd S.; Paxton, Jessica L.; Locke, Hannah S.; Barch, Deanna M.

2009-01-01

270

Soft Time-Suboptimal Controlling Structure for Mechanical Systems  

OpenAIRE

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, with uncertain (also non-stationary) mass treated as a stochastic process. The methodology proposed here is of a universal nature and may easily be applied with respect to other uncertainty element...

Kulczycki, Piotr; Wisniewski, Rafal; Kowalski, Piotr; Krawiec, Karol

2005-01-01

271

Designing Crane Controls with applied Mechanical and Electrical Safety Features  

Science.gov (United States)

The use of overhead traveling bridge cranes in many varied applications is common practice. In particular, the use of cranes in the nuclear, military, commercial, aerospace, and other industries can involve safety critical situations. Considerations for Human Injury or Casualty, Loss of Assets, Endangering the Environment, or Economic Reduction must be addressed. Traditionally, in order to achieve additional safety in these applications, mechanical systems have been augmented with a variety of devices. These devices assure that a mechanical component failure shall reduce the risk of a catastrophic loss of the correct and/or safe load carrying capability. ASME NOG-1-1998, (Rules for Construction of Overhead and Gantry Cranes, Top Running Bridge, and Multiple Girder), provides design standards for cranes in safety critical areas. Over and above the minimum safety requirements of todays design standards, users struggle with obtaining a higher degree of reliability through more precise functional specifications while attempting to provide "smart" safety systems. Electrical control systems also may be equipped with protective devices similar to the mechanical design features. Demands for improvement of the cranes "control system" is often recognized, but difficult to quantify for this traditionally "mechanically" oriented market. Finite details for each operation must be examined and understood. As an example, load drift (or small motions) at close tolerances can be unacceptable (and considered critical). To meet these high functional demands encoders and other devices are independently added to control systems to provide motion and velocity feedback to the control drive. This paper will examine the implementation of Programmable Electronic Systems (PES). PES is a term this paper will use to describe any control system utilizing any programmable electronic device such as Programmable Logic Controllers (PLC), or an Adjustable Frequency Drive (AID) 'smart' programmable motion controller. Therefore the use of the term Programmable Electronic Systems (PES) is an encompassing description for a large spectrum of programmable electronic control devices.

Lytle, Bradford P.; Walczak, Thomas A.; Delgado, H. (Technical Monitor)

2002-01-01

272

Optimal Control of Underactuated Mechanical Systems: A Geometric Approach  

OpenAIRE

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 d...

Colombo, L.; Diego, D. Martin; Zuccalli, M.

2009-01-01

273

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)

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 junction. Our data suggest that the location of P2Y receptors in lipid rafts speeds up the modulatory effect of ATP. Uncovered mechanisms may contribute to motor dysfunctions and neuromuscular diseases associated with oxidative stress. PMID:25463521

Giniatullin, A; Petrov, A; Giniatullin, R

2015-01-29

274

Estimulação elétrica neuromuscular em cães com atrofia muscular induzida / Neuromuscular electric stimulation in dogs with induced muscle atrophy  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Empregou-se a estimulação elétrica neuromuscular (EENM) de baixa freqüência no músculo quadríceps femoral de cães com atrofia induzida e avaliou-se a ocorrência de ganho de massa nessa musculatura. Foram utilizados oito cães com pesos entre 15 e 30kg, distribuídos aleatoriamente em dois grupos denom [...] inados de I ou controle e II ou tratado. A articulação femorotibiopatelar esquerda foi imobilizada por 30 dias pelo método de transfixação percutânea tipo II, com retirada de aparelho de imobilização após esse período. Decorridas 48 horas da remoção, foi realizada a EENM nos cães do grupo II, cinco vezes por semana, com intervalo de 24 horas cada sessão, pelo período de 60 dias. Foram avaliadas a circunferência da coxa, a goniometria do joelho, a análise clínica da marcha, as enzimas creatina-quinase (CK) e aspartato-amino-transferase (AST) e a morfometria das fibras musculares em cortes transversais do músculo vasto lateral colhido mediante biópsia muscular. A EENM foi empregada no músculo quadríceps femoral na freqüência de 50Hz, duração de pulso de 300 milisegundos e relação de tempo on/off de 1:2. Quanto à morfometria das fibras do músculo vasto lateral, no grupo tratado houve aumento significativo (P Abstract in english Low frequency neuromuscular electrical stimulation (NMES) was used on the femoral quadriceps of dogs with induced muscular atrophy and the occurrence of gain in mass in these muscles was evaluated. Eight dogs from 15 to 30kg were randomly distributed in two groups named I, or control; and II, or tre [...] ated. For the induction of muscular atrophy, the left femoral-tibial-patellar joint was immobilized for 30 days by percutaneous transfixation type II. After 30 days, the immobilization device was removed. The NMES treatment began 48 hours after the removal of the immobilization device of the dogs of group II, and it was carried out five times per week with an interval of 24 hours between each session, for 60 days. The following parameters were measured: thigh circumference, goniometry of the knee, clinical gait analysis, creatine kinase (CK) and aspartate aminotransferase (AST) enzymes, and morphometry of the muscular fibers in transversal cuts of the vastus lateralis muscle collected through muscular biopsy. The NMES was applied on the femoral quadriceps at a frequency of 50 Hz, with pulse duration of 300 milliseconds, and the on/off time was at a proportion of 1:2. Regarding the morphometry of the vastus lateralis fibers, a significant increase (P

C., Pelizzari; A., Mazzanti; A.G., Raiser; S.T.A., Lopes; D.L., Graça; A.T., Ramos; F.Z., Salbego; R., Festugatto; D.V., Beckmann; L.B., Souza; M.G.M.C.M., Cunha; R.P., Santos; B., Garmatz; A.P., Silva; D.A.F., Sturza.

2008-02-01

275

Peripheral nerve and neuromuscular junction pathology in Pompe disease.  

Science.gov (United States)

Pompe disease is a systemic metabolic disorder characterized by lack of acid-alpha glucosidase (GAA) resulting in ubiquitous lysosomal glycogen accumulation. Respiratory and ambulatory dysfunction are prominent features in patients with Pompe yet the mechanism defining the development of muscle weakness is currently unclear. Transgenic animal models of Pompe disease mirroring the patient phenotype have been invaluable in mechanistic and therapeutic study. Here, we demonstrate significant pathological alterations at neuromuscular junctions (NMJs) of the diaphragm and tibialis anterior muscle as prominent features of disease pathology in Gaa knockout mice. Postsynaptic defects including increased motor endplate area and fragmentation were readily observed in Gaa(-/-) but not wild-type mice. Presynaptic neuropathic changes were also evident, as demonstrated by significant reduction in the levels of neurofilament proteins, and alterations in axonal fiber diameter and myelin thickness within the sciatic and phrenic nerves. Our data suggest the loss of NMJ integrity is a primary contributor to the decline in respiratory and ambulatory function in Pompe and arises from both pre- and postsynaptic pathology. These observations highlight the importance of systemic phenotype correction, specifically restoration of GAA to skeletal muscle and the nervous system for treatment of Pompe disease. PMID:25217571

Falk, Darin J; Todd, Adrian Gary; Lee, Sooyeon; Soustek, Meghan S; ElMallah, Mai K; Fuller, David D; Notterpek, Lucia; Byrne, Barry J

2015-02-01

276

Obesity, mechanical and strength relationships to postural control in adolescence.  

Science.gov (United States)

There is preliminary evidence that BMI is positively correlated with movement variability of standing posture. However, this negative effect of obesity on postural control may be mediated by the change in other body scale variables (e.g., mechanical and fitness) that also occur with changes in BMI. This study investigated the influence of selected body scale (height, body mass, BMI), body composition (body fat percentage), mechanical (moment of inertia - MI) and strength (S) variables as predictors of the control of postural motion in adolescents. 125 healthy adolescents (65 boys, 60 girls) with a wide range of BMI (13.8-31.0 kg/m(2)) performed a battery of tests that assessed body composition, anthropometry, muscular strength and postural control. Multiple measures of postural motion variability were derived for analysis with body scale, mechanical and lower extremity strength variables separately for boys and girls. BMI, height and body mass, considered both separately and collectively, were poor and/or inconsistent predictors of variability in all three posture tasks. However, the ratio of lower extremity strength to whole body moment of inertia showed the highest positive correlation to most postural variability measures in both boys and girls and these effects were strongest in the less stable tasks of single leg standing and recovery of stance. Our findings support the hypothesis that diminished lower extremity strength to mechanical constraint ratio compromises the robustness of the strength to body scale relation in movement and postural control. PMID:22018701

King, Adam C; Challis, John H; Bartok, Cynthia; Costigan, F Aileen; Newell, Karl M

2012-02-01

277

Fluid Mechanics of Wing Adaptation for Separation Control  

Science.gov (United States)

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.

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

1997-01-01

278

Control of mechanical systems with rolling contacts: Applications to robotics  

Science.gov (United States)

The problems of modeling and control of mechanical dynamic systems subject to rolling contacts are investigated. There are two important theoretical contributions in this dissertation. First, contact kinematic relationships up to second order are developed for two rigid bodies in point contact. These equations relate gross rigid body motion to the changes in the positions of the points of contact. Second, a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints is proposed. The basic approach is to extend the state-space to include, in the addition to the generalized coordinates and velocities, contact coordinates which describe the displacements of the contact points and their derivatives. This redundant state-space formulation provides a convenient way to specify output equations to control contact motion. The control problem is formulated as an affine nonlinear problem and a differential-geometric, control-theoretic approach is used to decouple and linearize such systems. It is shown that such a system, even though not input-state linearizable, is input-output linearizable. Further, the zero dynamics of such a system is shown to be Lagrange stable. The proposed methodology is applied to three different robotic systems: (1) wheeled mobile robots; (2) two arms manipulating an object with rolling contact between each arm and the object; and (3) a single robot arm maintaining controlled contact against a moving environment. In each case, a nonlinear controller is designed to achieve the desired performances. For mobile robots, a new control algorithm called dynamic path following is proposed and shown to be quite effective and robust. In the context of two arm manipulation, grasp adaptation through the control of contact motion is demonstrated. Maintaining rolling contact with a moving surface is formulated as an acatastatic system. The proposed scheme involves simultaneously controlling interaction forces as well as the relative (rolling) motion. In all cases, computer simulations results are presented to demonstrate the efficacy of the control schemes.

Sarkar, Nilanjan

1993-01-01

279

Efeito do priming na redução da latência do pipecurônio, novo bloqueador neuromuscular não-despolarizante Efecto del priming en la reducción de la latencia del pipecuronio, nuevo bloqueador neuromuscular no despolarizante Effect of priming in shortening onset of pipecuronium, a new nondepolarizing neuromuscular blocker  

Directory of Open Access Journals (Sweden)

Full Text Available JUSTIFICATIVA E OBJETIVOS: Uma das mais importantes propriedades dos bloqueadores neuromusculares é o rápido início de ação, possibilitando intubação traqueal precoce. A administração de pequena dose de bloqueador não-despolarizante antes da dose plena é sabidamente redutora da latência da maioria dos bloqueadores neuromusculares utilizados. O brometo de pipecurônio é um agente aminoesteróide de longa duração com grande estabilidade cardiovascular, porém, com início de ação tardio. O objetivo desse estudo foi avaliar o efeito do priming do pipecurônio em pacientes adultos submetidos a cirurgias eletivas sob anestesia geral. MÉTODO: Foram estudados 33 pacientes adultos de ambos os sexos, com idade entre 20 e 65 anos, estado físico ASA I ou II, submetidos a cirurgias eletivas sob anestesia geral. Foram excluídos do estudo pacientes com insuficiência renal ou hepática, neuromiopatia, uso concomitante de drogas que influenciem a sua farmacocinética ou pacientes com histórico familiar de hipertermia maligna. Foram divididos em dois grupos: Grupo 1 onde foi utilizado o priming com 0,01 mg.kg-1 e três minutos depois completada a dose de 0,08 mg.kg-1 e o Grupo 2, sem dose priming (Grupo Controle. O relaxamento neuromuscular foi controlado pela aceleromiografia (Aparelho TOF-Guard e no momento em que T1 JUSTIFICATIVA Y OBJETIVOS: Una de las más importantes propiedades de los bloqueadores neuromusculares es el rápido inicio de acción, posibilitando intubación orotraqueal precoz. La administración de pequeña dosis del bloqueador no despolarizante antes de la dosis completa es consabidamente reductora de la latencia de la mayoría de los bloqueadores neuromusculares utilizados. El bromuro de pipecuronio es un agente aminoesteroide de larga duración con grande estabilidad cardiovascular, sin embargo, con inicio de acción tardía. El objetivo de ese estudio es evaluar el efecto del priming del pipecuronio en pacientes adultos sometidos a cirugías electivas bajo anestesia general. MÉTODO: Fueron estudiados 32 pacientes adultos de ambos sexos, con edad entre 20 y 65 años, estado físico ASA I ó II, a ser sometidos a cirugías electivas bajo anestesia general. Fueron excluidos del estudio pacientes con insuficiencia renal o hepática, neuromiopatia, uso concomitante de drogas que influencien la farmacocinética de la droga o pacientes con histórico familiar de hipertermia maligna. Fueron divididos en dos grupos: Grupo 1 donde fue utilizada el priming con 0,01 mg.kg-1 3 minutos después de completada la dosis de 0,08 mg.kg-1 y el Grupo 2, sin dosis priming (Grupo Control. El relajamiento neuromuscular fue controlado por la aceleromiografía (Aparato TOF-Guard y en el momento en que T1 BACKGROUND AND OBJECTIVES: One of the most important neuromuscular blockers property is short onset, allowing early tracheal intubation. Low nondepolarizing blocker dose before the full dose is known to decrease the onset of most neuromuscular blockers. Pipecuronium bromide is a long-lasting aminosteroid with major cardiovascular stability, however, with late onset. This study aimed at evaluating pipecuronium priming effect in adult patients submitted to elective surgeries under general anesthesia. METHODS: Participated in this study 33 adult patients of both genders, aged 20 to 65 years, physical status ASA I or II, to be submitted to elective surgeries under general anesthesia. Exclusion criteria were patients with kidney or liver failure, neuromuscular diseases, in concurrent use of drugs influencing pipecuronium pharmacokinetics, and patients with family history of malignant hyperthermia. Patients were divided in 2 groups: Group 1 = priming with 0.01 mg.kg-1 and 3 minutes later the remaining 0.07 mg.kg-1 (total 0.08 mg.kg-1; Group 2 = no priming dose (group control. Neuromuscular relaxation was controlled by acceleromyography (TOF-Guard device and laryngoscopy was accomplished when T1 < 10%. T test for independent samples was used for statistical analysis and Shapiro Wilks was used to test no

José Carlos Canga

2005-08-01

280

Mechanisms controlling the onset of simulated convectively coupled Kelvin waves  

Directory of Open Access Journals (Sweden)

Full Text Available Convectively coupled Kelvin waves (CCKW are analysed using a cloud-resolving model to gain a better understanding of the mechanisms that initiate and drive these waves. We compare the modelled precipitation and vertical structure of a convectively coupled Kelvin wave to the mechanisms that control precipitation over warm tropical oceans: convective inhibition (CIN, saturation fraction, atmospheric stability and surface moist entropy fluxes. Our results show that the primary onset mechanism for precipitation associated with CCKW is CIN associated with a decrease in the threshold moist entropy. Saturation fraction and atmospheric instability exhibit a time lag in comparison with the rainfall evolution and are, therefore, not primary controls in the onset of these waves. The modelled CCKW evolve by starting with congestus convection, develop into deep convection and decay with the stratiform convection. The results from the presented model agree with observations and linearised models.

Željka Fuchs

2014-01-01

281

Individuals with medial knee osteoarthritis show neuromuscular adaptation when perturbed during walking despite functional and structural impairments  

OpenAIRE

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...

Kumar, Deepak; Swanik, Charles; Reisman, Darcy S.; Rudolph, Katherine S.

2013-01-01

282

Fisiopatología de las alteraciones neuromusculares en el paciente crítico / Pathophysiology of neuromuscular impairments in the critically ill patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish Objetivo: Analizar las causas y manifestaciones de la debilidad muscular que desarrollan los pacientes críticos durante su estancia en la UCI y revisar la bibliografía. Desarrollo: A principios de los años 80 se describió en pacientes críticos sépticos una polineuropatía axonal mixta que clínicament [...] e se caracterizaba por una debilidad muscular de intensidad variable que en su vertiente más grave producía tetraplejia y/o dependencia del ventilador. Casi paralelamente se describió la miopatía aguda de los cuidados intensivos en pacientes asmáticos que eran ingresados en la UCI por exacerbación de su enfermedad. Con posterioridad se observó que esta miopatía se presentaba también en pacientes trasplantados, sépticos o quemados. Hay autores que consideran a la miopatía aguda de los cuidados intensivos como la primera causa de debilidad muscular en la UCI. Conclusiones: En este artículo se describen la clínica, etiopatogenia, diagnóstico y tratamiento de la polineuropatía del paciente crítico y de la miopatía aguda de los cuidados intensivos. Los dos cuadros clínicos son diferenciables en muchas ocasiones, siendo de gran ayuda los estudios neurofisiológicos y eventualmente la biopsia muscular. Aunque algunos autores prefieren englobar estas entidades bajo el nombre de polineuromiopatía, proponemos la denominación general de Síndrome Neuromuscular Agudo en el paciente crítico término más descriptivo, que no presupone un mecanismo ni una etiología única. Abstract in english Objective: to analyze the causes and manifestations of muscle weakness that critically ill patients develop during their staying at the ICU, and literature review. Development: in the early 1980s, a mixed axonal polyneuropathy was described in septic critically ill patients, which clinically manifes [...] ted by muscle weakness of variable severity, leading to quadriplegia and/or ventilator dependency in its most severe presentation. Almost at the same time, an acute intensive care myopathy was described in asthmatic patients admitted to the ICU for asthma exacerbation. Later on, this myopathy was also observed in transplanted, septic, or burnt patients. Several authors consider acute intensive care myopathy as the main cause of muscle weakness in the ICU. Conclusions: in this article, we describe the clinical presentation, etiopathogenesis, diagnosis, and treatment of polyneuropathy of the critically ill patient and of acute intensive care myopathy. Both clinical pictures may be differentiated, with neurophysiological studies and eventually muscle biopsy being of great help. Although some authors rather include these conditions under the name of polyneuromyopathy, we propose the general denomination of Acute Neuromuscular Syndrome of the Critically Ill Patient, a more descriptive term no presupposing a single mechanism or etiology.

A., García de Lorenzo; E., Vilas; J. A., Rodríguez Montes.

2006-05-01

283

Fisiopatología de las alteraciones neuromusculares en el paciente crítico Pathophysiology of neuromuscular impairments in the critically ill patients  

Directory of Open Access Journals (Sweden)

Full Text Available Objetivo: Analizar las causas y manifestaciones de la debilidad muscular que desarrollan los pacientes críticos durante su estancia en la UCI y revisar la bibliografía. Desarrollo: A principios de los años 80 se describió en pacientes críticos sépticos una polineuropatía axonal mixta que clínicamente se caracterizaba por una debilidad muscular de intensidad variable que en su vertiente más grave producía tetraplejia y/o dependencia del ventilador. Casi paralelamente se describió la miopatía aguda de los cuidados intensivos en pacientes asmáticos que eran ingresados en la UCI por exacerbación de su enfermedad. Con posterioridad se observó que esta miopatía se presentaba también en pacientes trasplantados, sépticos o quemados. Hay autores que consideran a la miopatía aguda de los cuidados intensivos como la primera causa de debilidad muscular en la UCI. Conclusiones: En este artículo se describen la clínica, etiopatogenia, diagnóstico y tratamiento de la polineuropatía del paciente crítico y de la miopatía aguda de los cuidados intensivos. Los dos cuadros clínicos son diferenciables en muchas ocasiones, siendo de gran ayuda los estudios neurofisiológicos y eventualmente la biopsia muscular. Aunque algunos autores prefieren englobar estas entidades bajo el nombre de polineuromiopatía, proponemos la denominación general de Síndrome Neuromuscular Agudo en el paciente crítico término más descriptivo, que no presupone un mecanismo ni una etiología única.Objective: to analyze the causes and manifestations of muscle weakness that critically ill patients develop during their staying at the ICU, and literature review. Development: in the early 1980s, a mixed axonal polyneuropathy was described in septic critically ill patients, which clinically manifested by muscle weakness of variable severity, leading to quadriplegia and/or ventilator dependency in its most severe presentation. Almost at the same time, an acute intensive care myopathy was described in asthmatic patients admitted to the ICU for asthma exacerbation. Later on, this myopathy was also observed in transplanted, septic, or burnt patients. Several authors consider acute intensive care myopathy as the main cause of muscle weakness in the ICU. Conclusions: in this article, we describe the clinical presentation, etiopathogenesis, diagnosis, and treatment of polyneuropathy of the critically ill patient and of acute intensive care myopathy. Both clinical pictures may be differentiated, with neurophysiological studies and eventually muscle biopsy being of great help. Although some authors rather include these conditions under the name of polyneuromyopathy, we propose the general denomination of Acute Neuromuscular Syndrome of the Critically Ill Patient, a more descriptive term no presupposing a single mechanism or etiology.

A. García de Lorenzo

2006-05-01

284

Control rod drive mechanisms in BWR type reactors  

International Nuclear Information System (INIS)

Purpose: To reduce the intrusion of chloride ions and water of highly dissolved oxygen content to control rod drive mechanisms and the reactor core as low as possible. Constitution: Driving water for control rod drive mechanisms is usually supplied from a condensate desalter. However, if the electroconductivity at the exit of the condensate desalter is increased due to sea water leakage in the condensor, the control rod driving water is automatically switched from that of condensate storage tank water and dissolved oxygen density in the condensate storage tank water is supplied as control rod driving water in which the dissolved oxygen density is reduced to about several tens ppb by the deareation. In this way, intrusion of chloride ions by way of the control rod driving mechanisms into the reactor core upon sea water leakage in the condensor can be decreased, as well as the stress corrosion crackings in the core components can be reduced since deareated water is used as the driving water. (Kamimura, M.)

285

Monitor circuit for a control rod drive mechanism  

International Nuclear Information System (INIS)

A monitor circuit for a control rod drive mechanism (crdm) that is adapted to detect erroneous stator phase sequences and generate a visible and audible alarm. The monitor circuit has particular application for use in connection with the control element assembly of a nuclear reactor. The monitor circuit includes an interface circuit for each stator phase winding of the drive motor, a plurality of logic gates to detect the predetermined erroneous phase sequences, a plurality of flipflops to maintain the fault condition signal, visible and audible alarm circuits, and circuitry for resetting the monitor circuit after a fault condition. The monitor circuit also includes a ratchet trip circuit for disengaging the clutch mechanism from the control rods when the rods are in motion in the time a fault condition is detected

286

A general framework for robust control in fluid mechanics  

Science.gov (United States)

The application of optimal control theory to complex problems in fluid mechanics has proven to be quite effective when complete state information from high-resolution numerical simulations is available [P. Moin, T.R. Bewley, Appl. Mech. Rev., Part 2 47 (6) (1994) S3-S13; T.R. Bewley, P. Moin, R. Temam, J. Fluid Mech. (1999), submitted for publication]. In this approach, an iterative optimization algorithm based on the repeated computation of an adjoint field is used to optimize the controls for finite-horizon nonlinear flow problems [F. Abergel, R. Temam, Theoret. Comput. Fluid Dyn. 1 (1990) 303-325]. In order to extend this infinite-dimensional optimization approach to control externally disturbed flows in which the controls must be determined based on limited noisy flow measurements alone, it is necessary that the controls computed be insensitive to both state disturbances and measurement noise. For this reason, robust control theory, a generalization of optimal control theory, has been examined as a technique by which effective control algorithms which are insensitive to a broad class of external disturbances may be developed for a wide variety of infinite-dimensional linear and nonlinear problems in fluid mechanics. An aim of the present paper is to put such algorithms into a rigorous mathematical framework, for it cannot be assumed at the outset that a solution to the infinite-dimensional robust control problem even exists. In this paper, conditions on the initial data, the parameters in the cost functional, and the regularity of the problem are established such that existence and uniqueness of the solution to the robust control problem can be proven. Both linear and nonlinear problems are treated, and the 2D and 3D nonlinear cases are treated separately in order to get the best possible estimates. Several generalizations are discussed and an appropriate numerical method is proposed.

Bewley, Thomas R.; Temam, Roger; Ziane, Mohammed

2000-04-01

287

Optimal piezo-electro-mechanical coupling to control plate vibrations  

CERN Document Server

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.

Alessandroni, S; Frezza, F

2010-01-01

288

Neuromuscular Fatigue During 200 M Breaststroke  

Directory of Open Access Journals (Sweden)

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.

Ana Conceição

2014-03-01

289

Telethonin protein expression in neuromuscular disorders.  

Science.gov (United States)

Telethonin is a 19-kDa sarcomeric protein, localized to the Z-disc of skeletal and cardiac muscles. Mutations in the telethonin gene cause limb-girdle muscular dystrophy type 2G (LGMD2G). We investigated the sarcomeric integrity of muscle fibers in LGMD2G patients, through double immunofluorescence analysis for telethonin with three sarcomeric proteins: titin, alpha-actinin-2, and myotilin and observed the typical cross striation pattern, suggesting that the Z-line of the sarcomere is apparently preserved, despite the absence of telethonin. Ultrastructural analysis confirmed the integrity of the sarcomeric architecture. The possible interaction of telethonin with other proteins responsible for several forms of neuromuscular disorders was also analyzed. Telethonin was clearly present in the rods in nemaline myopathy (NM) muscle fibers, confirming its localization to the Z-line of the sarcomere. Muscle from patients with absent telethonin showed normal expression for the proteins dystrophin, sarcoglycans, dysferlin, and calpain-3. Additionally, telethonin showed normal localization in muscle biopsies from patients with LGMD2A, LGMD2B, sarcoglycanopathies, and Duchenne muscular dystrophy (DMD). Therefore, the primary deficiency of calpain-3, dysferlin, sarcoglycans, and dystrophin do not seem to alter telethonin expression. PMID:12379311

Vainzof, Mariz; Moreira, Eloisa S; Suzuki, Oscar T; Faulkner, Georgine; Valle, Georgio; Beggs, Alan H; Carpen, Olli; Ribeiro, Alberto F; Zanoteli, Edmar; Gurgel-Gianneti, Juliana; Tsanaclis, Ana Maria; Silva, Helga C A; Passos-Bueno, Maria Rita; Zatz, Mayana

2002-10-01

290

Individuals with medial knee osteoarthritis show neuromuscular adaptation when perturbed during walking despite functional and structural impairments.  

Science.gov (United States)

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. PMID:24072409

Kumar, Deepak; Swanik, Charles Buz; Reisman, Darcy S; Rudolph, Katherine S

2014-01-01

291

Neuromuscular efficiency of the rectus abdominis differs with gender and sport practice.  

Science.gov (United States)

The purpose of this investigation was to distinguish the abilities of the rectus abdominis (RA) muscle according to gender and sport training by means of neuromuscular parameters extracted from electromyography (EMG)-torque relationships. Thirty-eight healthy students, divided into 4 groups (i.e., 8 male runners, 10 female gymnasts, 12 male controls, and 8 female controls) were asked to perform 6 seconds of isometric trunk flexions at 20%, 25%, 75%, and 100% of their maximal voluntary contraction. Flexion torque and surface EMG of the RA muscle were recorded simultaneously to construct a EMG-torque relationship. Under maximal and submaximal conditions, an index of neuromuscular efficiency (NME) was determined to characterize the capacity of the RA muscle to develop a torque. At each level of contraction, the area of data scattering (ADS), reflecting torque and EMG fluctuations, was computed to express the capacity to maintain a constant target torque. Flexion torque, NME, and ADS values differed significantly between genders, but when data were related to anthropometric characteristics, no difference was observed. Although runners were not distinguished from male controls, gymnasts had higher flexion torque, higher NME, and lower ADS values than female controls had. These differences should reflect neural and muscular adaptations linked to the specificity of gymnastic training. These findings revealed different functional abilities of the RA muscle, according to gender and sport practices. The indices of neuromuscular capacities used in this study could constitute complementary tools to athletic trainers and professionals in sports medicine for evaluating and following, during sport-specific training programs, the abdominal muscle performance implied in force transfers with a lower cost and lower risks of back pain. PMID:18978621

David, Pascal; Mora, Isabelle; Pérot, Chantal

2008-11-01

292

Development of moving coil type control rod drive mechanism  

International Nuclear Information System (INIS)

Kyoto University High Flux Reactor; 30 megawatt light water moderated reserarch reactor, has coupled cores in two separate core vessels surrounded by a heavy water reflector tank. Various investigations and tests were performed and a new type of control rod drive mechanism wa s developed. A plunger train connected to a control rod by a connecting rod in a guide tube is magnetically suspended with a coil train located out side of a guide tube. The drive mechanism developed has following merits. There is no leakage of core cooling water in principle because it has no sliding seal, rotary seal or reentrant thimble which are needed when the mechanisms pass through the core vessel. Maintenance is very easy because it has no complex mechanism in the core cooling water region. Scram for emergency shut down is performed on a loss of electric power. The control rod can be positioned continuously. This method will be applicable not only in nuclear reactors, but also in other plants in need of isolation. (author)

293

Membrane properties and excitatory neuromuscular transmission in the smooth muscle of dog cerebral arteries.  

OpenAIRE

1 Drug actions on electrical and mechanical properties of smooth muscle cells and neuromuscular transmission in the canine cerebral arteries were investigated by use of microelectrode and isometric tension recording methods. 2 In the basilar and middle cerebral arteries, the resting membrane potentials were--49.4 mV and -51.7 mV, respectively, the length constants 0.57 mm and 0.45 mm, respectively and the time constants 142 ms and 118 ms, respectively. 3 Outward current pulses did not evoke t...

Fujiwara, S.; Itoh, T.; Suzuki, H.

1982-01-01

294

Estudio electromiográfico de fibra aislada en enfermedades neuromusculares Single fiber electromyographic study in neuromuscular diseases  

Directory of Open Access Journals (Sweden)

Full Text Available Se implementó la electromiografía de fibra aislada en la práctica asistencial. Se realizó el estudio electromiográfico de fibra aislada de 191 pacientes con enfermedades neuromusculares. Se obtuvo una positividad de los estudios en el grupo de las radiculopatías de C6 del 15,2 %, para las lesiones del plexo braquial del 33, 3 %, para la esclerosis lateral amiotrófica del 44,1 %, para las miopatías del 21,9 % y se destaca la sensibilidad del mismo en el grupo de pacientes de miastenia gravis, que llegó al 70 %. Se concluye que se ratifica la alta sensibilidad del método de electromiografía de fibra aislada en el diagnóstico de la miastenia gravis y se señala su positividad moderada o baja en el resto de las enfermedades estudiadas.The single fiber electromyography was implemented in the health care practice. The single fiber electromyographic study of 191 patients with neuromuscular diseases was carried out. It was obtained a positivity of 15,2 % in the studies conducted in the group of C6 radiculopathies; 33,3 % in the brachial plexus injuries; 44,1 % in the amyotrophic lateral sclerosis; and 21,9 % in the myopathies. Its sensitivity was stressed in the group of patients with myasthenia gravis that reached 70 %. To conclude, it was ratified the high sensitivity of the method of single fibre electromyography in the diagnosis of myasthenia gravis, and it was underlined its moderate or low positivity in the rest of the studied diseases.

Roger Álvarez Fiallo

2005-06-01

295

Ecological production of dryland hairy vetch by mechanical control  

OpenAIRE

Winter hairy vetch, Vicia villosa Roth, gives high grain and hay yields. Mechanical control of weeds is an ecological alternative to the use of herbicides. Among the various mechanical methods, interrow weeding is cheap and practical. Nonetheless, wider row spacing than common practice is needed to ease the operation. We optimized row spacing and seed rates for high grain yield and to ease interrow cultivation. We used two row spacings of 45 and 60 cm as main plots and five seeding rates of 1...

Avci, Muzaffer; Akar, Taner

2006-01-01

296

Motivation and cognitive control: from behavior to neural mechanism.  

Science.gov (United States)

Research on cognitive control and executive function has long recognized the relevance of motivational factors. Recently, however, the topic has come increasingly to center stage, with a surge of new studies examining the interface of motivation and cognitive control. In the present article we survey research situated at this interface, considering work from cognitive and social psychology and behavioral economics, but with a particular focus on neuroscience research. We organize existing findings into three core areas, considering them in the light of currently vying theoretical perspectives. Based on the accumulated evidence, we advocate for a view of control function that treats it as a domain of reward-based decision making. More broadly, we argue that neuroscientific evidence plays a critical role in understanding the mechanisms by which motivation and cognitive control interact. Opportunities for further cross-fertilization between behavioral and neuroscientific research are highlighted. PMID:25251491

Botvinick, Matthew; Braver, Todd

2015-01-01

297

Wordlength Estimation of Digital Controller Synthesis for Inkjet Printer Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of finite wordlength on coefficients in implementing discrete-time controllers has been a subject of many recent studies. Especially, this issue is more severe in the low budget consumer electronic products when a faster sample rate is desired. To save the cost of development, most of the manufacturers applied cheap processors on those kinds of products. Therefore, it is desired to develop an estimation method to predict the required wordlength while designing a controller. In this paper, we will focus our study on the controller synthesis for an inkjet printing mechanism and investigate the effect insufficient wordlength. We will also develop an algorithm to estimate the required resolution and apply the method to determine the required bits of wordlength for the controller designed.

Hung-Ming Cheng

2008-04-01

298

Intravenous lidocaine has no impact on rocuronium-induced neuromuscular block. Randomised study  

OpenAIRE

Intravenous lidocaine is increasingly used in surgical patients. As it has neuromuscular blocking effects, we tested the impact of an intravenous lidocaine infusion on the time course of a rocuronium-induced neuromuscular block.

Czarnetzki, C.; Lysakowski, Christopher; Elia, Nadia; Tramer, Martin

2012-01-01

299

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)

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 knee pain (RR 0.27, CI 0.14 to 0.54 in military recruits. Conclusions Effective implementation of practical neuromuscular warm-up strategies can reduce lower extremity injury incidence in young, amateur, female athletes and male and female military recruits. This is typically a warm-up strategy that includes stretching, strengthening, balance exercises, sports-specific agility drills and landing techniques applied consistently for longer than three consecutive months. In order to optimize these strategies, the mechanisms for their effectiveness require further evaluation.

Herman Katherine

2012-07-01

300

Effects of hindlimb unloading on neuromuscular development of neonatal rats  

Science.gov (United States)

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.

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

301

New mechanism for the control of sodium transport in wheat  

International Nuclear Information System (INIS)

Full text: Durum and other tetraploid wheats are typically very salt-sensitive compared to hexaploid bread wheats. This is primarily due to high rates of Na+ accumulation in the leaves in tetraploid wheat. Recently, we have discovered a durum landrace with low Na+ accumulation and enhanced K+/Na+ discrimination, much lower than current durum cultivars and similar to bread wheat. We have identified 3 different mechanisms for the control of Na+ transport to the leaves in this landrace, 1) control of Na+ uptake at the epidermis of the root, 2) control of Na+ loading into the xylem and 3) partitioning of Na+ into the leaf sheath. The low Na+ durum landrace had 3-4 fold lower Na+ uptake rates than durum cultivars. Using X ray microanalysis on snap-frozen root sections, we found Na+ to be high in the epidermis, a decreasing gradient through the cortex, low in the endodermis and again high in the stele (pencycle and xylem parenchyma), indicative of control points at the epidermis and in the stele. Partitioning of Na+ between shoot and root was at least 5 times lower in the durum landrace, suggestive of greater control of Na+ transport at the site of xylem loading. A third and novel control mechanism was found in the leaf sheath. Short and long term salinity treatments showed that Na+ was partitioned preferentially into the > was partitioned preferentially into the sheaths of the low Na+ durum landrace, keeping leaf blade Na+ levels very low and similar to that of bread wheat Na+ partitioned in the leaf sheath was stored primarily in the parenchyma cells and Cl- in the epidermal cells. Collectively, these data show that we have identified germplasm that has the potential to increase the salt tolerance of durum wheat. Additionally, as bread wheat does not contain the mechanism for partitioning Na+ into the sheath, this trait may be useful for further increasing the salt tolerance of this species

302

ProBDNF and Mature BDNF as Punishment and Reward Signals for Synapse Elimination at Mouse Neuromuscular Junctions  

OpenAIRE

During development, mammalian neuromuscular junctions (NMJs) transit from multiple-innervation to single-innervation through axonal competition via unknown molecular mechanisms. Previously, using an in vitro model system, we demonstrated that the postsynaptic secretion of pro-brain-derived neurotrophic factor (proBDNF) stabilizes or eliminates presynaptic axon terminals, depending on its proteolytic conversion at synapses. Here, using developing mouse NMJs, we obtained in vivo evidence that p...

Je, H. Shawn; Yang, Feng; Ji, Yuanyuan; Potluri, Srilatha; Fu, Xiu-qing; Luo, Zhen-ge; Nagappan, Guhan; Chan, Jia Pei; Hempstead, Barbara; Son, Young-jin; Lu, Bai

2013-01-01

303

Fine Voltage Control Using Oltc by Static Tap Change Mechanism  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a novel model of fully electronic on load semiconductor tap changer for power transformer has been proposed. With high power semiconductor devices, problems associated with conventional mechanical on load tap changers which includes excessive conduction losses and arcing in the diverter switch have been properly rectified. In this work Simulink model was designed with GTOs as switching devices embedded in taps. Step change of voltage is achieved changing taps by switching GTOs and fine voltage with error less than ±0.1% is obtained by sequential firing control between GTOs in the system, which is not possible in conventional automatic OLTC control system.

S.V.M. Bhuvanaika rao , B.Subramanyeswar

2012-12-01

304

Mechanisms in Adaptive Feedback Control: Photoisomerization in a Liquid  

International Nuclear Information System (INIS)

The underlying mechanism for Adaptive Feedback Control in the experimental photoisomerization of 3,3'-diethyl-2,2'-thiacyanine iodide (NK88) in methanol is exposed theoretically. With given laboratory limitations on laser output, the complicated electric fields are shown to achieve their targets in qualitatively simple ways. Further, control over the cis population without laser limitations reveals an incoherent pump-dump scenario as the optimal isomerization strategy. In neither case are there substantial contributions from quantum multiple-path interference or from nuclear wave packet coherence. Environmentally induced decoherence is shown to justify the use of a simplified theoretical model

305

Optimal Control of Underactuated Mechanical Systems: A Geometric Approach  

CERN Document Server

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.

Colombo, L; Zuccalli, M

2009-01-01

306

Eletroestimulação neuromuscular, exercícios contrarresistência, força muscular, dor e função motora em pacientes com osteoartrite primária de joelho / Neuromuscular electrical stimulation, exercises against resistance, muscle strength, pain, and motor function in patients with primary osteoarthritis of the knee  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese INTRODUÇÃO: A osteoartrite (OA) do joelho é um processo degenerativo e os sintomas são dor mecânica e períodos de dor inflamatória, rigidez articular e fraqueza muscular. Ela não tem cura. O objetivo do tratamento é aliviar os sinais e sintomas e, quando possível, retardar sua evolução. O fortalecim [...] ento muscular é indicado como tratamento da OA. OBJETIVO: Comparar a eficácia da eletroestimulação neuromuscular (EENM) e de exercícios contrarresistência (ECR) no ganho de força extensora de joelho, na diminuição da dor e na recuperação da função motora em pacientes com OA primária do joelho. MATERIAIS E MÉTODOS: Participaram da pesquisa 23 pacientes com diagnóstico de OA primária do joelho, segundo os critérios clínicos e radiológicos do American College of Rheumatology. Eles foram alocados aleatoriamente para um grupo de ECR (n = 9), um grupo de EENM (n = 8) e um grupo controle (n = 6), e foram submetidos aos procedimentos característicos de seu grupo três vezes por semana até completar 24 sessões. Foram avaliadas de forma cega a força extensora de joelho, a dor e a função motora. Foi utilizado o teste MANOVA 3 x 2 com medidas repetidas para P Abstract in english INTRODUCTION: Knee osteoarthritis (OA) is a degenerative and the symptoms are mechanical pain and periods of inflammatory pain, joint stiffness and muscle weakness. OA has no cure and treatment serves to relieve the signs and symptoms and, when they can, slow its progression. Muscle strengthening is [...] indicated as the treatment. OBJECTIVE: To compare the effectiveness of NMES and resistance exercise in knee extensor strength gain, pain reduction and recovery of motor function in patients diagnosed with primary osteoarthritis of the knee. MATERIALS AND METHODS: Participated 23 patients with primary knee osteoarthritis, according to the clinical and radiological criteria of the American College of Rheumatology. Patients were randomly assigned to a group of resistance exercise (ECR n = 9), a group of neuromuscular electrical stimulation (NMES n = 8) and a control group (n = 6). They underwent characteristic procedures of their group three times per week until 24 sessions. The knee extensor strength pain and function were evaluated. Statistical analyses used was a 3 x 2 MANOVA with repeated measures, P

Thais Varanda, Dadalto; Cintia Pereira de, Souza; Elirez Bezerra da, Silva.

2013-12-01

307

Antenna mechanism of length control of actin cables  

CERN Document Server

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...

Mohapatra, Lishibanya; Kondev, Jane

2014-01-01

308

Cable control and take-up mechanisms and x-ray scanning apparatus incorporating such mechanisms  

International Nuclear Information System (INIS)

In this patent, an invention for cable control and take-up mechanisms for elongated, flexible cables is described. Such cables are used in X-ray scanner apparatus to provide power, electronic signals and fluids. A detailed design and description is given of the cable harness, control and take-up mechanism that would be used in conjunction with an X-ray scanner. As a result of this invention, the cables are prevented from becoming prematurely worn or entangled in the X-ray apparatus during the rotational and translational movements necessary in tomographic examinations. This invention is also applicable to other types of apparatus and environments where a number of different positions is required and where it is necessary to control the take-up of elongated, flexible, cable-like members. (U.K.)

309

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

Science.gov (United States)

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 movements. PMID:19227523

Latash, Mark L; Zatsiorsky, Vladimir M

2009-01-01

310

Mechanism and control of Genipa americana seed germination  

OpenAIRE

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 assessed by light and scanning electron microscopy during germination. Imbibition and germination curves were generated and over the same time interval endosperm digestion and resistance were measur...

Queiroz, S. E. E.; Silva, 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

311

Improving CRDM (Control Rod Drive Mechanism) penetration inspection  

International Nuclear Information System (INIS)

Since a through-wall longitudinal crack in a reactor vessel head penetration was discovered in September 1991, considerable efforts have been spent on developing techniques and equipment to detect such defects early. ABB claims to be the first company to have provided equipment and methods to carry out remote inspection of control rod drive mechanisms (CRDMs) and is still improving and extending its services. (author)

312

Workload Control Release Mechanisms: From Practice Back to Theory Building  

OpenAIRE

Abstract Much Workload Control research has focussed on the order release stage but failed to address practical considerations that impact practical application. Order release mechanisms have been developed through simulations that neglect job size variation effects while empirical evidence suggests groups of small/large jobs are often found in practice. When job sizes vary, it is difficult to release all jobs effectively – small jobs favour a short period between releases and a ...

Thu?rer, Matthias; Silva, Cristovao; Stevenson, M.

2010-01-01

313

Biogeochemical Mechanisms Controlling Reduced Radionuclide Particle Properties and Stability  

Energy Technology Data Exchange (ETDEWEB)

Uranium and Technetium are the major risk-driving contaminants at Hanford and other DOE sites. These radionuclides have been shown to be reduced by dissimilatory metal reducing bacteria (DMRB) under anoxic conditions. Laboratory studies have demonstrated that reduction results in the formation of poorly soluble hydrous oxides, UO2(s) and TcO2n?H2O(s), that are believed to limit mobility in the environment. The mechanisms of microbial reduction of U and Tc have been the focus of considerable research in the Environmental Remediation Sciences Program (ERSP). In spite of equal or greater importance in terms of controlling the environmental fate of the contaminants relatively little is known regarding the precipitation mechanism(s), reactivity, persistence, and transport of biogenic UO2(s) and TcO2(s).

Jim K. Fredrickson; John M. Zachara; Matthew J. Marshall; Alex S. Beliaev

2006-06-01

314

Mechanical design and optimal control of humanoid robot (TPinokio  

Directory of Open Access Journals (Sweden)

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.

Teck Chew Wee

2014-04-01

315

Rate-Controlling Mechanisms in Five-Power-Law Creep  

Energy Technology Data Exchange (ETDEWEB)

OAK-B135 Rate-Controlling Mechanisms in Five-Power-Law Creep. The initial grant emphasized the rate-controlling processes for five power-law creep. The effort has six aspects: (1) Theory of Taylor hardening from the Frank dislocation network in five power law substructures. (2) The dual dynamical and hardening nature of dislocations in five power law substructures. (3) Determination of the existence of long-range internal stress in five-power law creep dislocation substructures. (4) Dynamic recovery mechanisms associated with dislocation heterogeneities during five power law creep. (5) Versatility of five power law creep concept to other (hcp) crystal structures. (6) Writing of a book on ''Fundamental of Creep in Metals and Alloys'' by M.E. Kassner and Maria-Teresa Perez-Frado (postdoctoral scholar, funded by this project) Elsevier Press, 2004, in press. These areas are consistent with the original goals of this project as delineated in the original proposal to Basic Energy Sciences. The progress in each of these areas will be discussed separately and there will be an attempt to tie each aspect together so as to allow a summary regarding the conclusions with respect to the rate-controlling mechanisms of five power-law creep.

Michael E. Kassner

2004-04-20

316

Toxoplasmic encephalitis during mycophenolate mofetil immunotherapy of neuromuscular disease  

Science.gov (United States)

Objective: To show that immunotherapy with medications such mycophenolate mofetil (MMF) can cause serious complications in patients with neuromuscular disorders. Methods: Two patients with neuromuscular disorders on immunotherapy with long-term MMF who developed toxoplasmic encephalitis (TE) were included in this case series. Results: One patient with myasthenia gravis and one patient with inflammatory myopathy on immunotherapy with long-term MMF developed severe TE. Diagnosis was based on clinical presentation, MRI brain imaging characteristics, and CSF PCR positivity for Toxoplasma gondii. Both patients were treated with pyrimethamine, sulfadiazine, and leucovorin for 2 months without clinical improvement, and both died. Conclusions: Immunotherapy with medications such as MMF can cause devastating TE in non-HIV patients with neuromuscular disorders. Early consideration and recognition of this complication is important to possibly prevent unfavorable outcomes. The utility of screening and prophylaxis against toxoplasmosis in individuals with neuroimmunologic disorders and other autoimmune disorders who receive immunosuppressive therapy requires future study.

Chahin, Nizar

2015-01-01

317

Neuromuscular activity of Micrurus laticollaris (Squamata: Elapidae) venom in vitro.  

Science.gov (United States)

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 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. PMID:24445448

Carbajal-Saucedo, Alejandro; Floriano, Rafael Stuani; Dal Belo, Cháriston André; Olvera-Rodríguez, Alejandro; Alagón, Alejandro; Rodrigues-Simioni, Léa

2014-01-01

318

Hexosamine Biosynthetic Pathway Mutations Cause Neuromuscular Transmission Defect  

Science.gov (United States)

Neuromuscular junctions (NMJs) are synapses that transmit impulses from motor neurons to skeletal muscle fibers leading to muscle contraction. Study of hereditary disorders of neuromuscular transmission, termed congenital myasthenic syndromes (CMS), has helped elucidate fundamental processes influencing development and function of the nerve-muscle synapse. Using genetic linkage, we find 18 different biallelic mutations in the gene encoding glutamine-fructose-6-phosphate transaminase 1 (GFPT1) in 13 unrelated families with an autosomal recessive CMS. Consistent with these data, downregulation of the GFPT1 ortholog gfpt1 in zebrafish embryos altered muscle fiber morphology and impaired neuromuscular junction development. GFPT1 is the key enzyme of the hexosamine pathway yielding the amino sugar UDP-N-acetylglucosamine, an essential substrate for protein glycosylation. Our findings provide further impetus to study the glycobiology of NMJ and synapses in general. PMID:21310273

Senderek, Jan; Müller, Juliane S.; Dusl, Marina; Strom, Tim M.; Guergueltcheva, Velina; Diepolder, Irmgard; Laval, Steven H.; Maxwell, Susan; Cossins, Judy; Krause, Sabine; Muelas, Nuria; Vilchez, Juan J.; Colomer, Jaume; Mallebrera, Cecilia Jimenez; Nascimento, Andres; Nafissi, Shahriar; Kariminejad, Ariana; Nilipour, Yalda; Bozorgmehr, Bita; Najmabadi, Hossein; Rodolico, Carmelo; Sieb, Jörn P.; Steinlein, Ortrud K.; Schlotter, Beate; Schoser, Benedikt; Kirschner, Janbernd; Herrmann, Ralf; Voit, Thomas; Oldfors, Anders; Lindbergh, Christopher; Urtizberea, Andoni; von der Hagen, Maja; Hübner, Angela; Palace, Jacqueline; Bushby, Kate; Straub, Volker; Beeson, David; Abicht, Angela; Lochmüller, Hanns

2011-01-01

319

Morphometric and Morphological Analysis of Neuromuscular Junction Alterations in the Denervated Rat Diaphragm Evaluación de las Alteraciones Morfológicas y Morfométricas de las Uniones Neuromusculares del Diafragma Denervado en Ratas  

OpenAIRE

The morphological and structural alterations that occur in the neuromuscular junctions of the denervated rat diaphragm were studied. Fifteen adult male albino rats (Rattus norvegicus) aged about 60 days and with a mean weight of 200 g were used. Chronically denervated diaphragms were obtained and the animals were sacrificed after 4, 8 and 12 weeks of denervation. The left antimere of the diaphragm was denervated by section of the phrenic nerve and the right antimere was used as control. Each ...

Torrejais, M. M.; Soares, J. C.; Matheus, S. M. M.; Mello, J. M.; Francia-farje, L. A. D.; Vicente, E. J. D.

2009-01-01

320

Estimulação elétrica neuromuscular em cães submetidos à imobilização rígida temporária da articulação fêmoro-tíbio-patelar Neuromuscular electrical stimulation in dogs submitted to rigid temporary immobilization of femmoral-tibial-patellar joint  

OpenAIRE

Com o objetivo de avaliar o efeito da estimulação elétrica neuromuscular (EENM) de baixa freqüência sobre o músculo vasto lateral, foram utilizados 11 cães, agrupados aleatoriamente em três grupos, denominados de I ou controle, de II (EENM após imobilização) e de III (EENM durante e após imobilização). A articulação fêmoro-tíbio-patelar direita foi imobilizada por 30 dias pelo método de transfixação percutânea tipo II. Os cães do grupo III iniciaram as sessões de eletr...

Soraia Figueiredo de Souza; Alexandre Mazzanti; Alceu Gaspar Raiser; Fabiano Zanini Salbego; Charles Pelizzari; Danieli Brollo Martins; Raquel Rubia Rech; Sonia Terezinha dos Anjos Lopes; Diego Vilibaldo Beckmann; Lucilene Bernardi de Souza; Marina Gabriela Carvalho Mori da Cunha; Rafael Festugatto; Rosmarini Passos dos Santos; Ana Paula da Silva

2007-01-01

321

Control of cardiac alternans by mechanical and electrical feedback  

Science.gov (United States)

A persistent alternation in the cardiac action potential duration has been linked to the onset of ventricular arrhythmia, which may lead to sudden cardiac death. A coupling between these cardiac alternans and the intracellular calcium dynamics has also been identified in previous studies. In this paper, the system of PDEs describing the small amplitude of alternans and the alternation of peak intracellular Ca2+ are stabilized by optimal boundary and spatially distributed actuation. A simulation study demonstrating the successful annihilation of both alternans on a one-dimensional cable of cardiac cells by utilizing the full-state feedback controller is presented. Complimentary to these studies, a three variable Nash-Panfilov model is used to investigate alternans annihilation via mechanical (or stretch) perturbations. The coupled model includes the active stress which defines the mechanical properties of the tissue and is utilized in the feedback algorithm as an independent input from the pacing based controller realization in alternans annihilation. Simulation studies of both control methods demonstrate that the proposed methods can successfully annihilate alternans in cables that are significantly longer than 1 cm, thus overcoming the limitations of earlier control efforts.

Yapari, Felicia; Deshpande, Dipen; Belhamadia, Youssef; Dubljevic, Stevan

2014-07-01

322

Controller modeling and evaluation for PCV electro-mechanical actuator  

Science.gov (United States)

Hydraulic actuators are currently used to operate the propellant control valves (PCV) for the space shuttle main engine (SSME) and other rocket engines. These actuators are characterized by large power to weight ratios, large force capabilities, and rapid accelerations, which favor their use in control valve applications. However, hydraulic systems are also characterized by susceptibility to contamination, which leads to frequent maintenance requirements. The Control Mechanisms Branch (EP34) of the Component Development Division of the Propulsion Laboratory at the Marshall Space Flight Center (MSFC) has been investigating the application of electromechanical actuators as replacements for the hydraulic units in PCV's over the last few years. This report deals with some testing and analysis of a PCV electromechanical actuator (EMA) designed and fabricated by HR Textron, Inc. This prototype actuator has undergone extensive testing by EP34 personnel since early 1993. At this time, the performance of the HR Textron PCV EMA does not meet requirements for position tracking.

Parker, Joey K.

1993-11-01

323

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

Science.gov (United States)

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. PMID:25448864

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

2015-01-01

324

Bloqueio neuromuscular prolongado após administração de mivacúrio: relato de caso / Prolonged neuromuscular block after mivacurium: case report / Bloqueo neuromuscular prolongado después de administración de mivacúrio: relato de caso  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: Com a introdução de novos fármacos com ação de curta duração, houve aumento do número de procedimentos realizados em caráter ambulatorial. O mivacúrio com duração de ação entre 15 e 30 minutos e metabolismo enzimático tornou-se opção de bloqueador neuromuscular para estes [...] procedimentos. O relato de caso tem como objetivo chamar a atenção para a ocorrência de bloqueio neuromuscular prolongado após administração do mivacúrio e as condutas que foram adotadas. RELATO DO CASO: Descreve-se um caso de paciente programado para procedimento de curta duração em regime ambulatorial e que apresentou bloqueio neuromuscular prolongado após administração do mivacúrio. O diagnóstico foi posteriormente confirmado pela demonstração de níveis reduzidos de atividade da colinestesterase plasmática. CONCLUSÕES: A investigação laboratorial pré-operatória, mesmo incluindo a dosagem da atividade da colinesterase, não previne a possibilidade do bloqueio neuromuscular prolongado devido à possibilidade de alteração qualitativa da atividade da enzima, não existindo recomendação para investigação sistemática. Ocorrendo esta complicação, deve-se sedar o paciente e manter ventilação mecânica até a completa recuperação da força muscular e realizar exames laboratoriais para o diagnóstico definitivo. É de responsabilidade do anestesiologista a coleta de amostra sangüínea para realização de testes quantitativos e qualitativos da colinesterase plasmática. Paciente e familiares devem ser orientados quanto à importância da investigação para classificação da variante atípica da colinesterase plasmática e suas implicações anestésicas. Abstract in spanish JUSTIFICATIVA Y OBJETIVOS: Con la introducción de nuevos fármacos con acción de corta duración, hubo aumento del número de procedimientos realizados en carácter ambulatorial. El mivacúrio con duración de acción entre 15 y 30 minutos y metabolismo enzimático se volvió opción de bloqueador neuromuscul [...] ar para estos procedimientos. El relato de caso tiene como objetivo llamar la atención para la ocurrencia de bloqueo neuromuscular prolongado después de la administración del mivacúrio y las conductas que fueron adoptadas. RELATO DEL CASO: Se describe un caso de paciente programado para procedimiento de corta duración en régimen ambulatorial y que presentó bloqueo neuromuscular prolongado después de administración del mivacúrio. El diagnóstico fue posteriormente confirmado por la demostración de niveles reducidos de actividad de la colinestesterasis plasmática. CONCLUSIONES: La averiguación laboratorial pre-operatoria, mismo incluyendo la dosificación de la actividad de la colinesterasis, no precave la posibilidad del bloqueo neuromuscular prolongado debido a la posibilidad de alteración cualitativa de la actividad de la enzima, no existiendo recomendación para averiguación sistemática. Ocurriendo esta complicación, se debe sedar el paciente y mantener ventilación mecánica hasta la completa recuperación de la fuerza muscular y realizar exámenes laboratoriales para el diagnóstico definitivo. Es de responsabilidad del anestesista la colecta de muestra sanguínea para realización de tests cuantitativos y cualitativos de la colinesterasis plasmática. Paciente y familiares deben ser orientados en cuanto a la importancia de la averiguación para clasificación de la variante atípica de la colinesterasis plasmática y sus implicaciones anestésicas. Abstract in english BACKGROUND AND OBJECTIVES: With the introduction of new drugs with short action, there has been increase in the number of outpatient procedures. Mivacurium, with duration of action of 15-30 minutes and enzymatic metabolism has become the neuromuscular blocker of choice for these procedures. This cas [...] e report aim at calling the attention to prolonged neuromuscular block after mivacurium and its management approaches. CASE

Karina Bernardi, Pimenta.

2005-10-01

325

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

DEFF Research Database (Denmark)

Hemiparesis-disability and muscle weakness of 1 side of the body-is a common consequence of stroke. High-intensity strength training may be beneficial to regain function, but strength coaches in the field of rehabilitation need evidence-based guidelines. The purpose of this study was to evaluate 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 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 consisting of isokinetic muscle strength, neuromuscular activation measured with electromyography (EMG), electrically evoked muscle twitch contractile properties, and gait performance (10-m Walk Test and 6-min Walk Test). After the 12-week conditioning program, knee extensor and flexor strength increased during all contraction modes and velocities in the paretic leg. Significant increases were observed for agonist EMG amplitude at slow concentric and slow eccentric contraction. Twitch torque increased, whereas twitch time-to-peak tension remained unchanged. By contrast, no significant changes were 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 gait velocity. Strength training coaches working in the field of rehabilitation can use this knowledge to safely and efficiently add high-intensity strength training to existing rehabilitation paradigms.

Andersen, Lars L; Zeeman, Peter

2011-01-01

326

Web-based neuromuscular simulator applied to the teaching of principles of neuroscience  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english INTRODUCTION: The learning of core concepts in neuroscience can be reinforced by a hands-on approach, either experimental or computer-based. In this work, we present a web-based multi-scale neuromuscular simulator that is being used as a teaching aid in a campus-wide course on the Principles of Neur [...] oscience. METHODS: The simulator has several built-in individual models based on cat and human biophysics, which are interconnected to represent part of the neuromuscular system that controls leg muscles. Examples of such elements are i) single neurons, representing either motor neurons or interneurons mediating reciprocal, recurrent and Ib inhibition; ii) afferent fibers that can be stimulated to generate spinal reflexes; iii) muscle unit models, generating force and electromyogram; and iv) stochastic inputs, representing the descending volitional motor drive. RESULTS: Several application examples are provided in the present report, ranging from studies of individual neuron responses to the collective action of many motor units controlling muscle force generation. A subset of them was included in an optional homework assignment for Neuroscience and Biomedical Engineering graduate students enrolled in the course cited above at our University. Almost all students rated the simulator as a good or an excellent learning tool, and approximately 90% declared that they would use the simulator in future projects. CONCLUSION: The results allow us to conclude that multi-scale neuromuscular simulator is an effective teaching tool. Special features of this free teaching resource are its direct usability from any browser (http://remoto.leb.usp.br/), its user-friendly graphical user interface (GUI) and the preset demonstrations.

Leonardo Abdala, Elias; André Fabio, Kohn.

2013-09-01

327

Neuromuscular strain as a contributor to cognitive and other symptoms in chronic fatigue syndrome: hypothesis and conceptual model.  

Science.gov (United States)

Individuals with chronic fatigue syndrome (CFS) have heightened sensitivity and increased symptoms following various physiologic challenges, such as orthostatic stress, physical exercise, and cognitive challenges. Similar heightened sensitivity to the same stressors in fibromyalgia (FM) has led investigators to propose that these findings reflect a state of central sensitivity. A large body of evidence supports the concept of central sensitivity in FM. A more modest literature provides partial support for this model in CFS, particularly with regard to pain. Nonetheless, fatigue and cognitive dysfunction have not been explained by the central sensitivity data thus far. Peripheral factors have attracted attention recently as contributors to central sensitivity. Work by Brieg, Sunderland, and others has emphasized the ability of the nervous system to undergo accommodative changes in length in response to the range of limb and trunk movements carried out during daily activity. If that ability to elongate is impaired-due to movement restrictions in tissues adjacent to nerves, or due to swelling or adhesions within the nerve itself-the result is an increase in mechanical tension within the nerve. This adverse neural tension, also termed neurodynamic dysfunction, is thought to contribute to pain and other symptoms through a variety of mechanisms. These include mechanical sensitization and altered nociceptive signaling, altered proprioception, adverse patterns of muscle recruitment and force of muscle contraction, reduced intra-neural blood flow, and release of inflammatory neuropeptides. Because it is not possible to differentiate completely between adverse neural tension and strain in muscles, fascia, and other soft tissues, we use the more general term "neuromuscular strain." In our clinical work, we have found that neuromuscular restrictions are common in CFS, and that many symptoms of CFS can be reproduced by selectively adding neuromuscular strain during the examination. In this paper we submit that neuromuscular strain is a previously unappreciated peripheral source of sensitizing input to the nervous system, and that it contributes to the pathogenesis of CFS symptoms, including cognitive dysfunction. PMID:23720638

Rowe, Peter C; Fontaine, Kevin R; Violand, Richard L

2013-01-01

328

Response to aerobic exercise training in humans with neuromuscular disease.  

Science.gov (United States)

There have been few studies examining the response of persons with neuromuscular disease and postpolio syndrome to cardiopulmonary testing and aerobic exercise training. In persons with neuromuscular disease that directly involves the cardiac and respiratory systems, deficits in performance may be primarily due to these limitations, along with loss of functional muscle tissue from the disease process. In the more slowly progressive disorders, deconditioning may play an important role in limiting aerobic exercise performance and may be amenable to training. Recommendations are provided for future exercise studies with these populations. PMID:12409819

Kilmer, David D

2002-11-01

329

Neuromuscular exercise as treatment of degenerative knee disease  

DEFF Research Database (Denmark)

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.

Ageberg, Eva; Roos, Ewa M.

2015-01-01

330

Mechanisms of flow control with the unsteady bleed technique  

Science.gov (United States)

The unsteady bleed technique (a.k.a. internal acoustic forcing) has been shown to be an effective method for control of separation on low Reynolds number airfoils, blunt-end cylinders aligned axially with the flow, cylinders aligned perpendicular to the flow, and forebody geometries at high angles of attack. In many of these investigations, the mechanism for the control has been attributed to enhancement of the shear layer (Kelvin-Helmholtz) instability by the unsteady component of the forcing. However, this is not the only possible mechanism, nor may it be the dominant mechanism under some conditions. In this work it is demonstrated that at least two other mechanisms for flow control are present, and depending on the location and the amplitude of the forcing, these may have significant impact on the flow behavior. Experiments were conducted on a right-circular cylinder with a single unsteady bleed slot aligned along the axis of the cylinder. The effects of forcing frequency, forcing amplitude, and slot location on the azimuthal pressure distribution were studied. The results suggest that a strong vortical structure forms near the unsteady bleed slot when the slot location is upstream of the boundary layer separation point. The structure is unsteady, since it is created by the unsteady forcing. The 'vortex' generates a sizeable pressure spike (C(sub p) = -3.0) in the time-averaged pressure field immediately downstream of the slot. In addition to the pressure spike, the boundary layer separation location moves farther downstream when the forcing is activated. Delay of the separation is believed to be a result of enhancing the Kelvin-Helmholtz instability. When forcing is applied in a quiescent wind tunnel, a weak low-pressure region forms near the slot that is purely the result of the second-order streaming effect.

Williams, D. R.; Acharya, M.; Bernhardt, J.

1992-01-01

331

Suramin inhibits the early effects of PLA2 neurotoxins at mouse neuromuscular junctions: A twitch tension study  

OpenAIRE

Several phospholipase A2 (PLA2) neurotoxins from snake venoms can affect acetylcholine release at the neuromuscular junction. In isolated nerve-muscle preparations three distinct phases have been described for this phenomenon: An initial transient decrease in twitch tension; a second facilitatory phase during which twitch height is greater than control twitch height; and the last phase which causes a reduction in twitch height that finally results in paralysis. Suramin has been reported to in...

Fathi, Behrooz; Harvey, Alan L.; Rowan, Edward G.

2011-01-01

332

The drop height determines neuromuscular adaptations and changes in jump performance in stretch-shortening cycle training  

OpenAIRE

There is an ongoing discussion about how to improve jump performance most efficiently with plyometric training. It has been proposed that drop height influences the outcome, although longitudinal studies are missing. Based on cross-sectional drop jump studies showing height-dependent Hoffmann (H)-reflex activities, we hypothesized that the drop height should influence the neuromuscular activity and thus, the training result. Thirty-three subjects participated as a control or in one of two str...

Taube, Wolfgang; Leukel, Christian; Lauber, B.; Gollhofer, Albert

2012-01-01

333

Estudio electromiográfico de fibra aislada en enfermedades neuromusculares / Single fiber electromyographic study in neuromuscular diseases  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish Se implementó la electromiografía de fibra aislada en la práctica asistencial. Se realizó el estudio electromiográfico de fibra aislada de 191 pacientes con enfermedades neuromusculares. Se obtuvo una positividad de los estudios en el grupo de las radiculopatías de C6 del 15,2 %, para las lesiones d [...] el plexo braquial del 33, 3 %, para la esclerosis lateral amiotrófica del 44,1 %, para las miopatías del 21,9 % y se destaca la sensibilidad del mismo en el grupo de pacientes de miastenia gravis, que llegó al 70 %. Se concluye que se ratifica la alta sensibilidad del método de electromiografía de fibra aislada en el diagnóstico de la miastenia gravis y se señala su positividad moderada o baja en el resto de las enfermedades estudiadas. Abstract in english The single fiber electromyography was implemented in the health care practice. The single fiber electromyographic study of 191 patients with neuromuscular diseases was carried out. It was obtained a positivity of 15,2 % in the studies conducted in the group of C6 radiculopathies; 33,3 % in the brach [...] ial plexus injuries; 44,1 % in the amyotrophic lateral sclerosis; and 21,9 % in the myopathies. Its sensitivity was stressed in the group of patients with myasthenia gravis that reached 70 %. To conclude, it was ratified the high sensitivity of the method of single fibre electromyography in the diagnosis of myasthenia gravis, and it was underlined its moderate or low positivity in the rest of the studied diseases.

Roger, Álvarez Fiallo; Carlos, Santos Anzorandia; Esther, Medina Herrera; Rosa, Jiménez Paneque; Ángela, Gutiérrez Sánchez.

2005-06-01

334

Pressure and volume controlled mechanical ventilation in anaesthetized pregnant sheep.  

Science.gov (United States)

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 tension was higher in the PCV group (P = 0.013). Mean and diastolic pressures were lower in the PCV group (P = 0.029 and P = 0.047, respectively). Both VCV and PCV provide adequate oxygenation of pregnant sheep anaesthetized in dorsal recumbency, though PCV may provide superior oxygenation at a lower PIP. PMID:25057010

Davis, J; Musk, G C

2014-10-01

335

Genetic and evolutionary analysis of the Drosophila larval neuromuscular junction  

Science.gov (United States)

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 has identified a rich source of material for discovery of novel genes and mechanisms that regulate synaptic growth and development, and has also provided new insights into the mechanisms that underlie morphological evolution of nervous systems.

Campbell, Megan

336

Cost-control mechanisms in Canadian private drug plans.  

Science.gov (United States)

Approximately 68% of Canadians receive prescription drug coverage through an employer-sponsored private plan. However, we have very limited data on the structure of these plans. This study aims to identify and describe the use of cost-control mechanisms in private drug plans in Canada and describe what private coverage looks like for the average Canadian. Using 2010 data from over 113,000 different private drug plans, provided by Applied Management Consultants, we determined the overall use of key cost-control measures, and the cost-control tools that appear to be gaining currency compared to a report on benefits coverage in 1998. We found that the use of common cost-control measures is relatively low among Canadian private benefits programs. Co-insurance is much more common in private coverage plans than co-payments. Deductibles are uncommon in Canada and, when in place, are very small. The use of annual and lifetime maximums is increasing. Canadian private benefits programs use few cost-control measures to respond to increasing costs, particularly in comparison to their public counterparts. These results suggest there are ample opportunities for greater efficiency in private sector drug coverage plans. PMID:23968672

Kratzer, Jillian; McGrail, Kimberlyn; Strumpf, Erin; Law, Michael R

2013-08-01

337

Control of mechanical systems on Lie groups and ideal hydrodynamics  

CERN Document Server

In contrast to the Euler-Poincar{\\'e} reduction of geodesic flows of left- or right-invariant metrics on Lie groups to the corresponding Lie algebra (or its dual), one can consider the reduction of the geodesic flows to the group itself. The reduced vector field has a remarkable hydrodynamic interpretation: it is a velocity field for a stationary flow of an ideal fluid. Right- or left-invariant symmetry fields of the reduced field define vortex manifolds for such flows. Consider now a mechanical system, whose configuration space is a Lie group and whose Lagrangian is invariant to left translations on that group, and assume that the mass geometry of the system may change under the action of internal control forces. Such system can also be reduced to the Lie group. With no controls, this mechanical system describes a geodesic flow of the left-invariant metric, given by the Lagrangian, and thus its reduced flow is a stationary ideal fluid flow on the Lie group. The standard control problem for such system is to ...

Deryabin, Mikhail V

2007-01-01

338

Digital PI Controller Using Anti-Wind-Up Mechanism for A Speed Controlled Electric Drive System  

Directory of Open Access Journals (Sweden)

Full Text Available This paper discusses the implementation of Digital PI Controller Using Anti Wind-Up Mechanism For A Speed Controlled Electric Drive System. To eliminate the system zeros relocated proportional integral controller is implemented. Which in turn reduces the over shoots. The torque is not limited, inspite of the use of relocated proportional integral controller. The motor windings get damaged, if the torque reaches higher values. In order to limit this torque, we introduce a torque limiter, which limits the torque value to the permissible limits. Due to limited torque, over shoots are produced for large inputs. To eliminate these overshoots, with limited torque, we implement the anti-windup mechanism. The scheme is implemented in MATLAB and from the obtained results its possible use and limitations are studied for torque limits varying from +3000 to +7000 N-m.

Srikanth Mandarapu,

2013-06-01

339

A neuromuscular mechanism of posttraumatic osteoarthritis associated with ACL injury.  

Science.gov (United States)

Anterior cruciate ligament (ACL) injury leads to early-onset osteoarthritis. Quadriceps weakness is a consequence of ACL injury and is considered to result from arthrogenic inhibition (AMI). AMI is the neurological "shutdown" of muscles surrounding an injured joint, preventing full activation, reducing strength, and promoting atrophy. As quadriceps function is critical for energy absorption, its dysfunction may contribute to posttraumatic osteoarthritis. PMID:19550206

Palmieri-Smith, Riann M; Thomas, Abbey C

2009-07-01

340

Repouso da junção neuromuscular no tratamento de crises miastênicas e colinérgicas Management of the myasthenic and cholinergic crisis by neuromuscular junction rest  

Directory of Open Access Journals (Sweden)

Full Text Available Os autores trataram 18 crises miastênicas e colinérgicas desenvolvidas em 12 pacientes com forma generalizada e severa de miastenia grave, mediante o "repouso" da junção neuromuscular. Êste foi conseguido, em um grupo de 6 enfermos, pela suspensão das drogas anticolinesterásicas, emprego da respiração artificial e alimentação por sonda nasogástrica — "repouso relativo". Outro grupo de 6 pacientes foi submetido ao "repouso absoluto" da junção neuromuscular, mediante o uso da respiração artificial, alimentação por sonda nasogástrica e curarização prolongada pela galamina. Em mais de 50% das crises observaram-se melhoras imediatas e acentuadas com o método de tratamento pelo "repouso" da junção neuromuscular, ao lado de redução significativa da taxa de mortalidade nas crises. A evolução mostrou que os pacientes que responderam melhor durante e logo após o tratamento da crise, tiveram, também, melhor evolução ulterior. Dos 12 enfermos somente um era portador de timoma e, mesmo nesse paciente, a evolução foi satisfatória. A sensibilidade inicial ao curare foi muito grande em todos os doentes submetidos à curarização prolongada, mas, em prazo relativamente curto (alguns dias, esta hipersensibilidade diminuiu sensivelmente. Apesar de todos os cuidados, as infecções respiratórias foram a regra, exigindo tratamento enérgico e bem orientado.The neuromuscular junction rest method was employed in the treatment of 18 myasthenic and cholinergic crisis occurring in 12 patients with severe forms of myasthenia gravis. Six of these patients received a "relative rest" and other six patients received an "absolute rest" treatment. In the first group of patients the method consisted essentially in withdrawal of anticholinesterase therapy and mechanical respiratory support with early performance of traqueostomy and use of the intermitente positive pressure breathing (I.P.P.B. with cuffed traqueostomy tube. The patients of second group, in addition to this management, were submitted to prolonged curarization by galamine (Flaxedil by intramuscular injection; all of them presented an initial curare supersensitivity which always decreased shortly. In both methods the reinstitution of the drug therapy was progressive. The respirator weanned of progressively and the patients were kept under observation for adequate ventilation. The doses were variable but subsequent doses of antimyasthenic medications were determined by clinical findings and response to the tensilon or prostigmine tests. The doses were increased or decreased accordingly in each individual case, rapid changes of drug doses to perfect adjustment being undesirable in this transition period. Partial or temporary remission occurred in some patients. Others were able to sustain satisfactory ventilation for a long period or definitively. Most of the crisis improved and most of the patients benefited from the therapeutic method of the neuromuscular junction rest. There was a remarkable reduction in the mortality rate from the crisis. One patient had a thymoma which was malignant; in spite of this the evolution of this case has been good after the treatment. Those patients who had immediate good response to the treatment of the crisis had a favorable fellow up, even a complete remission. Respiratory infections were very common in spite of all cares. Culture of tracheal secretions and wound exsudates were made. Bactericidal and broad-spectrum antibiotics were used, depending of the laboratory report cf patient's sensitivity. Physiotherapy besides other prophylactic measures was used against bronchopneumonia. Atelectasis was a common complication in the crisis and all efforts to prevent it were made, including daily clinical examination of pulmonary conditions, Vt,, blood pressure and bed side chest films. The routine use of atropine sulfate promoved inspissation of bronchial secretions, plugging of the bronchi, and attendant atelectasis, infection and bronchopneumonia. Exceptionally, steroids or bronchoscopy had been used.

J. Lamartine de Assis

1968-06-01

341

Repouso da junção neuromuscular no tratamento de crises miastênicas e colinérgicas / Management of the myasthenic and cholinergic crisis by neuromuscular junction rest  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os autores trataram 18 crises miastênicas e colinérgicas desenvolvidas em 12 pacientes com forma generalizada e severa de miastenia grave, mediante o "repouso" da junção neuromuscular. Êste foi conseguido, em um grupo de 6 enfermos, pela suspensão das drogas anticolinesterásicas, emprego da respiraç [...] ão artificial e alimentação por sonda nasogástrica — "repouso relativo". Outro grupo de 6 pacientes foi submetido ao "repouso absoluto" da junção neuromuscular, mediante o uso da respiração artificial, alimentação por sonda nasogástrica e curarização prolongada pela galamina. Em mais de 50% das crises observaram-se melhoras imediatas e acentuadas com o método de tratamento pelo "repouso" da junção neuromuscular, ao lado de redução significativa da taxa de mortalidade nas crises. A evolução mostrou que os pacientes que responderam melhor durante e logo após o tratamento da crise, tiveram, também, melhor evolução ulterior. Dos 12 enfermos somente um era portador de timoma e, mesmo nesse paciente, a evolução foi satisfatória. A sensibilidade inicial ao curare foi muito grande em todos os doentes submetidos à curarização prolongada, mas, em prazo relativamente curto (alguns dias), esta hipersensibilidade diminuiu sensivelmente. Apesar de todos os cuidados, as infecções respiratórias foram a regra, exigindo tratamento enérgico e bem orientado. Abstract in english The neuromuscular junction rest method was employed in the treatment of 18 myasthenic and cholinergic crisis occurring in 12 patients with severe forms of myasthenia gravis. Six of these patients received a "relative rest" and other six patients received an "absolute rest" treatment. In the first gr [...] oup of patients the method consisted essentially in withdrawal of anticholinesterase therapy and mechanical respiratory support with early performance of traqueostomy and use of the intermitente positive pressure breathing (I.P.P.B.) with cuffed traqueostomy tube. The patients of second group, in addition to this management, were submitted to prolonged curarization by galamine (Flaxedil by intramuscular injection); all of them presented an initial curare supersensitivity which always decreased shortly. In both methods the reinstitution of the drug therapy was progressive. The respirator weanned of progressively and the patients were kept under observation for adequate ventilation. The doses were variable but subsequent doses of antimyasthenic medications were determined by clinical findings and response to the tensilon or prostigmine tests. The doses were increased or decreased accordingly in each individual case, rapid changes of drug doses to perfect adjustment being undesirable in this transition period. Partial or temporary remission occurred in some patients. Others were able to sustain satisfactory ventilation for a long period or definitively. Most of the crisis improved and most of the patients benefited from the therapeutic method of the neuromuscular junction rest. There was a remarkable reduction in the mortality rate from the crisis. One patient had a thymoma which was malignant; in spite of this the evolution of this case has been good after the treatment. Those patients who had immediate good response to the treatment of the crisis had a favorable fellow up, even a complete remission. Respiratory infections were very common in spite of all cares. Culture of tracheal secretions and wound exsudates were made. Bactericidal and broad-spectrum antibiotics were used, depending of the laboratory report cf patient's sensitivity. Physiotherapy besides other prophylactic measures was used against bronchopneumonia. Atelectasis was a common complication in the crisis and all efforts to prevent it were made, including daily clinical examination of pulmonary conditions, Vt,, blood pressure and bed side chest films. The routine use of atropine sulfate promoved inspissation of bronchial secretions, plugging of the bronchi, and attendant atelecta

J. Lamartine de, Assis; Paulo A. P., Saraiva.

1968-06-01

342

Neuromuscular electrical stimulation during recovery from exercise: a systematic review.  

Science.gov (United States)

The use of subtetanic low-intensity neuromuscular electrical stimulation (NMES) for the purpose of promoting recovery from exercise has increased in recent years. The aim of this systematic review was to assess the effects of NMES on exercise recovery. A computerized database search of PubMed, CINAHL Plus, Sport Discus, and Cochrane Library electronic databases was conducted for the time period of January 1, 1970 to March 8, 2012. Only studies that used healthy uninjured humans and motor threshold electrical stimulation compared with at least one other recovery modality for the purpose of promoting recovery from exercise were eligible for selection. Thirteen studies satisfied the inclusion criteria and were included for analysis (11 randomized crossover trials, 1 randomized control trial [RCT], and 1 classified as other [OTH]). A quality assessment rating of the studies was performed using an extended version of The Cochrane Collaboration's tool for assessing risk of bias. Because of the heterogeneity of the study protocols, a qualitative review (best evidence synthesis) was performed for all outcomes, whereas the results for blood lactate (BLa) were also included in a meta-analysis. Eight studies were classified as high quality, 4 as medium quality, and 1 as low quality. Three studies found a positive outcome for a subjective measure of muscle pain, 3 for BLa, 1 for lowering creatine kinase, and only 1 for a performance parameter. The meta-analysis showed no evidence in favor of NMES vs. active (ACT) and mixed evidence vs. passive (PAS) recovery for BLa. In conclusion, although there may be some subjective benefits for postexercise recovery, evidence is not convincing to support NMES for enhancing subsequent performance. PMID:24552796

Malone, John K; Blake, Catherine; Caulfield, Brian M

2014-09-01

343

Bellows for control rod drive mechanisms of 'MONJU'  

International Nuclear Information System (INIS)

The full mock-up operation test of Control Rod Drive Mechanism (CRDM) for 'MONJU' has been carried out since 1972 in OEC of PNC. Welded type bellows were adopted for CRDM as the boundary between sodium and atmosphere. In design, two different locations were considered for bellows, one in sodium and the other in argon gas with sodium vapor and some experiences on the bellows have been obtained. Besides the prototype tests of CRDM, several R and D on CRDM bellows, such as environment effect test and endurance test are conducted. (author)

344

Mechanism of controlled crack formation in thin-film dielectrics  

International Nuclear Information System (INIS)

Thin films on substrate may crack due to tensile residual stress taking a mud crack like pattern. The pattern can be controlled by prescribing stress raisers that initiate, and arresters that terminate, cracks at desired locations. Here, we describe the mechanism by which stresses are amplified in plasma-deposited films. Stress raisers in the form of narrow slits or features with sharp corners are reactive ion etched in silicon. Plasma deposition of thin films on these stress raisers causes a nonconformal coverage leading to the formation of narrow voids within the slits. On annealing, the voids amplify the stress and initiate cracks through the thickness of the film

345

Electromagnetic control rod drive mechanism, with reduced heat losses  

International Nuclear Information System (INIS)

The electromagnetic device can be used for the control rod drive mechanism of a pressurized coater reactor. It has a sealed casing extending from the reactor cover containing two mobile poles and a mobile plunger, a coil moving the first pole to grip or release the rod, a second coil moving the plunger against the second pole to grip the rod, a third coil moving the second pole, and a cut-out for a thermal coolant siphon associated with the first pole and coil

346

Bellows for control rod drive mechanism of 'MONJU'  

International Nuclear Information System (INIS)

The full mock-up operation test of Control Rod Drive Mechanism (CRDM) for ''MONJU'' have been carried on since 1972 in OEC of PNC. Welded type bellows were adopted for CRDM as the boundary between sodium and atmosphere. In design, two different locations were considered for bellows, one in sodium and the other in argon gas with sodium vapor and some experiences on the bellows have been obtained. Besides the prototype tests of CRDM, several R and D on CRDM bellows, such as environment effect test and endurance test are conducted. (author)

347

Auxiliary remote controlled release for positive action mechanism  

International Nuclear Information System (INIS)

The positive action mechanism has a ram with a shaft connected at one extremity to an action part and at the other to a push piece having a spring. A spindle, parallel to the shaft of the ram is mounted inside a case joined to the body of the ram. A screw nut is engaged with the threaded part of the spindle and is connected to a prolongator that engages on the shaft of the ram to displace the shaft as the spindle is rotated. The end part of the spindle has a connector to allow remote controlled equipment to rotate the spindle

348

Active control of mechanical structures in research and education  

Directory of Open Access Journals (Sweden)

Full Text Available Several crucial phases of the overall approach to development and design of smart structures are outlined in this paper. They are focused on control of lightweight mechanical structures with respect to active vibration and noise attenuation using piezoelectric actuators and sensors. The research experience and growing interest in development of smart structures have motivated introduction of courses on smart structures at universities, which are being studied extensively and with great interest by young researchers and students. Some of the author’s experiences regarding education in this field will be addressed as well.

Nestorovi? Tamara N.

2013-01-01

349

Alteration in neuromuscular function of the plantar flexors following caffeine ingestion.  

Science.gov (United States)

The aim of this study was to compare the neuromuscular function of the plantar flexors following caffeine or placebo administration. Thirteen subjects (25?±?3 years) ingested caffeine or placebo in a randomized, controlled, counterbalanced, double-blind crossover design. Neuromuscular tests were performed before and 1?h after caffeine or placebo intake. During neuromuscular testing, rate of torque development, isometric maximum voluntary torque, and neural drive to the muscles were measured. Triceps surae muscle activation was assessed by normalized root mean square of the EMG signal during the initial phase of contraction (0-100?ms, 100-200?ms) and maximal voluntary contraction (MVC). Furthermore, evoked spinal reflex responses of the soleus muscle (H-reflex evoked at rest and during MVC, V-wave) and peak twitch torques were evaluated. The isometric maximum voluntary torque and evoked potentials were not different. However, we found a significant difference between groups for rate of torque development in the time intervals 0-100?ms [41.1?N·m/s (95% CI: 8.3-73.9?N·m/s, P?=?0.016)] and 100-200?ms [32.8?N·m/s (95% CI: 2.8-62.8?N·m/s, P?=?0.034)]. These changes were accompanied by enhanced neural drive to the plantar flexors. Data suggest that caffeine solely increased explosive voluntary strength of the triceps surae because of enhanced neural activation at the onset of contraction whereas MVC strength was not affected. PMID:24798789

Behrens, Martin; Mau-Moeller, Anett; Heise, Sandra; Skripitz, Ralf; Bader, Rainer; Bruhn, Sven

2015-02-01

350

Neuromuscular exercise improves functional performance in patients with severe hip osteoarthritis  

DEFF Research Database (Denmark)

Purpose. Exercise is regarded a cornerstone in the treatment of mild to moderate osteoarthritis (OA). However, little is known of the effects in patients with advanced and end-stage OA. The purpose was to evaluate the effect of neuromuscular exercise in patients with severe hip OA. Methods. Design. 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 in detail. Assessments were carried out at baseline and within one week after the intervention. Outcomes. Functional performance: 20-m walk at maximal pace and 5 repeated chair stands timed. Muscle power: Unilateral multi-joint leg extension power and unilateral single-joint knee extension power evaluated with a leg extension press (Nottingham Power Rig, Nottingham University, Nottingham, UK) and a seated knee extension machine (Oemmebi, Moglia, Italy) adapted with a linear encoder (MuscleLab Power, Ergotest Technology, Langesund, Norway), respectively. Results. On average the intervention group attended 13±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 to the NEMEX-TJR program improves functional performance and leg extension power in patients with severe OA of the hip joint.

Villadsen, Allan; Overgaard, SØren

351

Assessment of ventilatory neuromuscular drive in patients with obstructive sleep apnea  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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

L.R.A., Bittencourt; S.M.T., Moura; M.C., Bagnato; L.C., Gregório; S., Tufik; L.E., Nery.

1998-04-01

352

Assessment of ventilatory neuromuscular drive in patients with obstructive sleep apnea  

Directory of Open Access Journals (Sweden)

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

L.R.A. Bittencourt

1998-04-01

353

Control and Virtual Reality Simulation of Tendon Driven Mechanisms  

International Nuclear Information System (INIS)

In this paper the authors present a control strategy for tendon driven mechanisms. The aim of the control system is to find the correct torques which the motors have to exert to make the end effector describe a specific trajectory. In robotic assemblies this problem is often solved with closed loop algorithm, but here a simpler method, based on a open loop strategy, is developed. The difficulties in the actuation are in keeping the belt tight during all working conditions. So an innovative solution of this problem is presented here. This methodology can be easily applied in real time monitoring or very fast operations. For this reason several virtual reality simulations, developed using codes written in Virtual Reality Markup Language, are also presented. This approach is very efficient because it requires a very low cpu computation time, small size files, and the manipulator can be easily put into different simulated scenarios

354

The sagital balance in idiopatic and neuromuscular scoliosis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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 investig [...] ation 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 (PT) 10.19; Lumbar Lordosis (LL) 43.48; and Thoracic Kyphosis (TK) 32.10. In NMS: PI 53.77; SS 42.31; PT 11.46; LL 49.46; and TK 45.69. No statistically significant differences in PEP distribution were found between the two types of scoliosis (p=0,057). The association between pelvic incidence and lumbar lordosis is low among idiopathic scoliosis (R=0,074) and neuromuscular scoliosis (R=0,274). CONCLUSION: PEP measurements in a Brazilian population of idiopathic scoliosis and neuromuscular scoliosis patients are similar to those in the international literature and do not differ statistically between them. The association between LL and PI could not be assessed in this study. Level of Evidence IV, Case Series.

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

2014-07-01

355

Neuromuscular exercise as treatment of degenerative knee disease.  

Science.gov (United States)

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 traditionally used strength or aerobic training but aims to target more closely the sensorimotor deficiencies and functional instability associated with the degenerative knee disease than traditionally used training methods. PMID:25390299

Ageberg, Eva; Roos, Ewa M

2015-01-01

356

Biochemistry of Neuromuscular Diseases: A Course for Undergraduate Students  

Science.gov (United States)

This article outlines an undergraduate course focusing on supramolecular membrane protein complexes involved in the molecular pathogenesis of neuromuscular disorders. The emphasis of this course is to introduce students to the key elements involved in the ion regulation and membrane stabilization during muscle contraction and the role of these…

Ohlendieck, Kay

2002-01-01

357

Uranium dioxide sintering Kinetics and mechanisms under controlled oxygen potentials  

International Nuclear Information System (INIS)

The initial, intermediate, and final sintering stages of uranium dioxide were investigated as a function of stoichiometry and temperature by following the kinetics of the sintering reaction. Stoichiometry was controlled by means of the oxygen potential of the sintering atmosphere, which was measured continuously by solid-state oxygen sensors. Included in the kinetic study were microspheres originated from UO2 gels and UO2 pellets produced by isostatic pressing ceramic grade powders. The microspheres sintering behavior was examined using hot-stage microscopy and a specially designed high-temperature, controlled atmosphere furnace. This same furnace was employed as part of an optical dilatometer, which was utilized in the UO2 pellet sintering investigations. For controlling the deviations from stoichiometry during heat treatment, the oxygen partial pressure in the sintering atmosphere was varied by passing the gas through a Cu-Ti-Cu oxygen trap. The trap temperature determined the oxygen partial pressure of the outflowing mixture. Dry hydrogen was also used in some of the UO sub(2+x) sintering experiments. The determination of diametrial shrinkages and sintering indices was made utilizing high-speed microcinematography and ultra-microbalance techniques. It was observed that the oxygen potential has a substantial influence on the kinetics of the three sintering stages. The control of the sintering atmosphere oxygen partial pressure led to very fast densification of UO sub(2+x). Values in the interval 95.0 to 99.5% of theoretical density were reached in less than one minute. Uranium volume diffusion is the dominant mechanism in the initial and intermediate sintering stages. For the final stage, uranium grain boundary diffusion was found to be the main sintering mechanism. (Author)

358

A Cell-Level Mechanism of Contrast Gain Control  

CERN Document Server

The gain of neurons' responses in the auditory cortex is sensitive to contrast changes in the stimulus within a spectrotemporal range similar to their receptive fields, which can be interpreted to represent the tuning of the input to a neuron. This indicates a local mechanism of contrast gain control, which we explore with a minimal mechanistic model here. Gain control through noisy input has been observed in vitro and in a range of computational models. We investigate the behaviour of the simplest of such models to showcase gain control, a stochastic leaky integrate-and-fire (sLIF) neuron, which exhibits gain control through divisive normalisation of the input both with and without accompanying subtractive shift of the input-response curve, depending on whether input noise is proportional to or independent of its mean. To get a more direct understanding of how the input statistics change the response, we construct an analytic approximation to the firing rate of a sLIF neuron constituted of the expression for...

Schumacher, Linus J

2013-01-01

359

Discrete Mechanics and Optimal Control for Space Trajectory Design  

Science.gov (United States)

Space trajectory design is often achieved through a combination of dynamical systems theory and optimal control. The union of trajectory design techniques utilizing invariant manifolds of the planar circular restricted three-body problem and the optimal control scheme Discrete Mechanics and Optimal Control (DMOC) facilitates the design of low-energy trajectories in the N-body problem. In particular, DMOC is used to optimize a trajectory from the Earth to the Moon in the 4-body problem, removing the mid-course change in velocity, Delta V, usually necessary for such a trajectory while still exploiting the structure from the invariant manifolds. This thesis also focuses on how to adapt DMOC, a method devised with a constant step size, for the highly nonlinear dynamics involved in trajectory design. Mesh refinement techniques that aim to reduce discretization errors in the solution and energy evolution and their effect on DMOC optimization are explored and compared with trajectories created using time adaptive variational integrators. Furthermore, a time adaptive form of DMOC is developed that allows for a variable step size that is updated throughout the optimization process. Time adapted DMOC is based on a discretization of Hamilton's principle applied to the time adapted Lagrangian of the optimal control problem. Variations of the discrete action of the optimal control Lagrangian lead to discrete Euler-Lagrange equations that can be enforced as constraints for a boundary value problem. This new form of DMOC leads to the accurate and efficient solution of optimal control problems with highly nonlinear dynamics. Time adapted DMOC is tested on several space trajectory problems including the elliptical orbit transfer in the 2-body problem and the reconfiguration of a cubesat.

Moore, Ashley

360

Estimulação elétrica neuromuscular em cães com atrofia muscular induzida Neuromuscular electric stimulation in dogs with induced muscle atrophy  

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Full Text Available Empregou-se a estimulação elétrica neuromuscular (EENM de baixa freqüência no músculo quadríceps femoral de cães com atrofia induzida e avaliou-se a ocorrência de ganho de massa nessa musculatura. Foram utilizados oito cães com pesos entre 15 e 30kg, distribuídos aleatoriamente em dois grupos denominados de I ou controle e II ou tratado. A articulação femorotibiopatelar esquerda foi imobilizada por 30 dias pelo método de transfixação percutânea tipo II, com retirada de aparelho de imobilização após esse período. Decorridas 48 horas da remoção, foi realizada a EENM nos cães do grupo II, cinco vezes por semana, com intervalo de 24 horas cada sessão, pelo período de 60 dias. Foram avaliadas a circunferência da coxa, a goniometria do joelho, a análise clínica da marcha, as enzimas creatina-quinase (CK e aspartato-amino-transferase (AST e a morfometria das fibras musculares em cortes transversais do músculo vasto lateral colhido mediante biópsia muscular. A EENM foi empregada no músculo quadríceps femoral na freqüência de 50Hz, duração de pulso de 300 milisegundos e relação de tempo on/off de 1:2. Quanto à morfometria das fibras do músculo vasto lateral, no grupo tratado houve aumento significativo (PLow frequency neuromuscular electrical stimulation (NMES was used on the femoral quadriceps of dogs with induced muscular atrophy and the occurrence of gain in mass in these muscles was evaluated. Eight dogs from 15 to 30kg were randomly distributed in two groups named I, or control; and II, or treated. For the induction of muscular atrophy, the left femoral-tibial-patellar joint was immobilized for 30 days by percutaneous transfixation type II. After 30 days, the immobilization device was removed. The NMES treatment began 48 hours after the removal of the immobilization device of the dogs of group II, and it was carried out five times per week with an interval of 24 hours between each session, for 60 days. The following parameters were measured: thigh circumference, goniometry of the knee, clinical gait analysis, creatine kinase (CK and aspartate aminotransferase (AST enzymes, and morphometry of the muscular fibers in transversal cuts of the vastus lateralis muscle collected through muscular biopsy. The NMES was applied on the femoral quadriceps at a frequency of 50 Hz, with pulse duration of 300 milliseconds, and the on/off time was at a proportion of 1:2. Regarding the morphometry of the vastus lateralis fibers, a significant increase (P<0.05 in the transversal area of the treated group at 90 days was observed when compared with that identified at the time of immobilization. Thus, it can be concluded that low frequency NMES brings about hypertrophy of the vastus lateralis muscle in dogs after temporary rigid immobilization of the knee joint.

C. Pelizzari

2008-02-01

361

Tensiomyography method used for neuromuscular assessment of muscle training  

Science.gov (United States)

Background Within the structure of the skeletal muscle, there are fascicles of muscular fibers that are made up of serially distributed contractile elements. These elements are controlled by the nervous system, control which results in obtaining the muscular strength required for movement and its control. This study presents the neuromuscular assessment using tensiomyography method (TMG). Methods We studied two groups of soccer junior players, group 1 (experimental group) and group 2 (control group), each containing 15 soccer players; we have considered two situations of muscle training: the combination between the isometric-concentric contraction for group 1 and the concentric contraction for group 2. TMG is the electrical stimulation of the muscle group and the recording of the muscle parameters resulting after the isometric contraction: time contraction (Tc) and displacement (Dm) at rectus femoris muscle (RF), pointing out two moments T1 and T2. Results Tc decreasing and the Dm increasing involve a good response following the muscle training. For group 1, the Tc evolution is 22.54 ms/22.45 ms (T1/T2) for the right RF and 22.65 ms/22.26 ms for the left RF, while for group 2 results in a Tc evolution of 24.33 ms/28.57 ms (T1/T2) for the right RF and 25.74 ms/28.61 ms for the left RF. Dm for group 1, results in a 6.57 mm/6.85 mm (T1/T2) for the right RF and 6.92 mm/7.06 mm for the left RF, while for group 2, the Dm evolution shows 7.45 mm/5.83 mm (T1/T) for the right RF and 7.41 mm/6.26 mm for the left RF. Also, the evaluation on motor test indicated better results on T2 for the experimental group. Summarizing the results of Student t-test, we found significant differences between the averages of the two groups in all parameters (p?develop muscle training which can be monitored through TMG. PMID:23822158

2013-01-01

362

Central chemoreceptors and neural mechanisms of cardiorespiratory control  

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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.

T.S. Moreira

2011-09-01

363

Mechanism for hydrotalcite decomposition: a controlled rate thermal analysis study.  

Science.gov (United States)

The mechanism for the decomposition of hydrotalcite remains unsolved. Controlled rate thermal analysis enables this decomposition pathway to be explored. Hydrotalcites containing carbonate, vanadate and molybdate were prepared by coprecipitation. The resulting materials were characterised by XRD, simultaneous TG-DTG-DTA and controlled rate thermal analysis (CRTA) to determine the stability and thermal decomposition pathway of the synthesised hydrotalcites. For the carbonate intercalated hydrotalcite dehydration takes place in three steps two of which are quasi-isothermal and one non-isothermal. Dehydroxylation and decarbonation occur separately over the 235-330 and 330-370 degrees C temperature range. A second non-isothermal decarbonation step is observed in the 371-541 degrees C range. In comparison the mixed carbonate-vanadate and carbonate-molybdate hydrotalcites show two dehydration steps and the dehydroxylation and decarbonation occur simultaneously. The observation of three dehydration steps is used to support the model of water molecules in three structurally distinct environments in the hydrotalcite interlayer. CRTA technology provides a mechanism for the decomposition of hydrotalcites. PMID:17991479

Vágvölgyi, Veronika; Palmer, Sara J; Kristóf, János; Frost, Ray L; Horváth, Erzsébet

2008-02-15

364

Central chemoreceptors and neural mechanisms of cardiorespiratory control  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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 circu [...] latory 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.

T.S., Moreira; A.C., Takakura; R.S., Damasceno; B., Falquetto; L.T., Totola; C.R., Sobrinho; D.T., Ragioto; F.P., Zolezi.

2011-09-01

365

Mechanism of controlled release kinetics from medical devices  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

A., Raval; J., Parikh; C., Engineer.

2010-06-01

366

Neuromuscular Activity of Micrurus laticollaris (Squamata: Elapidae Venom in Vitro  

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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.

Alejandro Carbajal-Saucedo

2014-01-01

367

Auction Mechanism to Allocate Air Traffic Control Slots  

Science.gov (United States)

This article deals with an auction mechanism for airspace slots, as a means of solving the European airspace congestion problem. A disequilibrium, between Air Traffic Control (ATC) services supply and ATC services demand are at the origin of almost one fourth of delays in the air transport industry in Europe. In order to tackle this congestion problem, we suggest modifying both pricing and allocation of ATC services, by setting up an auction mechanism. Objects of the auction will be the right for airlines to cross a part of the airspace, and then to benefit from ATC services over a period corresponding to the necessary time for the crossing. Allocation and payment rules have to be defined according to the objectives of this auction. The auctioneer is the public authority in charge of ATC services, whose aim is to obtain an efficient allocation. Therefore, the social value will be maximized. Another objective is to internalize congestion costs. To that end, we apply the principle of Clarke-Groves mechanism auction: each winner has to pay the externalities imposed on other bidders. The complex context of ATC leads to a specific design for this auction.

Raffarin, Marianne

2003-01-01

368

Controlled nerve ablation with direct current: parameters and mechanisms.  

Science.gov (United States)

Spastic hypertonus (muscle over-activity) often develops after spinal cord injury or stroke. Chemodenervating agents such as Botulinum toxin A (BtA) and phenol are often used to treat this condition. We have previously shown that the use of direct current (DC) to create controlled lesions of peripheral nerves may provide a means of reducing spastic hypertonus. Here, we explored a range of stimulation parameters that could be used clinically. Nerves were lesioned with DC in chronically implanted animals and the outcome was tracked over many months. In addition, we used DC to ablate nerves in animals with decerebrate rigidity (an animal model of spastic hypertonus) and we explored the possible mechanisms of DC nerve ablation. We found that nerve ablation with DC was effective in reducing hypertonus. Some stimulation paradigms were more likely to be clinically acceptable than others. Furthermore we showed that nerve regeneration occurs in the months following DC nerve ablation and we demonstrated that the ablation procedure is repeatable, much like BtA treatment. Regarding mechanism, our results did not support the hypothesis that DC caused nerve damage by overactivating sodium channels. Rather, the mechanism of damage seems to be related to changes in pH. PMID:24760938

Ravid, Einat; Prochazka, Arthur

2014-11-01

369

Neuromuscular disease. DOK7 gene therapy benefits mouse models of diseases characterized by defects in the neuromuscular junction.  

Science.gov (United States)

The neuromuscular junction (NMJ) is the synapse between a motor neuron and skeletal muscle. Defects in NMJ transmission cause muscle weakness, termed myasthenia. The muscle protein Dok-7 is essential for activation of the receptor kinase MuSK, which governs NMJ formation, and DOK7 mutations underlie familial limb-girdle myasthenia (DOK7 myasthenia), a neuromuscular disease characterized by small NMJs. Here, we show in a mouse model of DOK7 myasthenia that therapeutic administration of an adeno-associated virus (AAV) vector encoding the human DOK7 gene resulted in an enlargement of NMJs and substantial increases in muscle strength and life span. When applied to model mice of another neuromuscular disorder, autosomal dominant Emery-Dreifuss muscular dystrophy, DOK7 gene therapy likewise resulted in enlargement of NMJs as well as positive effects on motor activity and life span. These results suggest that therapies aimed at enlarging the NMJ may be useful for a range of neuromuscular disorders. PMID:25237101

Arimura, Sumimasa; Okada, Takashi; Tezuka, Tohru; Chiyo, Tomoko; Kasahara, Yuko; Yoshimura, Toshiro; Motomura, Masakatsu; Yoshida, Nobuaki; Beeson, David; Takeda, Shin'ichi; Yamanashi, Yuji

2014-09-19

370

Aging interferes central control mechanism for eccentric muscle contraction  

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Full Text Available Previous studies report greater activation in the cortical motor network in controlling eccentric contraction (EC than concentric contraction (CC despite lower muscle activation level associated with EC vs. CC in healthy, young individuals. It is unknown, however, whether elderly people exhibiting increased difficulties in performing EC than CC possess this unique cortical control mechanism for EC movements. To address this question, we examined functional MRI (fMRI data acquired during EC and CC of the first dorsal interosseous (FDI muscle in 11 young (20-32 years and 9 old (67-73 years individuals. During the fMRI experiment, all subjects performed 20 CC and 20 EC of the right FDI with the same angular distance and velocity. The major findings from the behavioral and fMRI data analysis were that (1 movement stability was poorer in EC than CC in the old but not the young group; (2 similar to previous electrophysiological and fMRI reports, the EC resulted in significantly stronger activation in the motor control network consisting of primary, secondary and association motor cortices than CC in the young and old groups; (3 the biased stronger activation towards EC was significantly greater in the old than the young group especially in the secondary and association cortices such as supplementary and premotor motor areas and anterior cingulate cortex; and (4 in the primary motor and sensory cortices, the biased activation towards EC was significantly greater in the young than the old group. Greater activation in higher-order cortical fields for controlling EC movement by elderly adults may reflect activities in these regions to compensate for aging-related impairments in the ability to control complex EC movements. Our finding is useful for potentially guiding the development of targeted therapies to counteract age-related movement deficits and to prevent injury.

Wan X. Yao

2014-05-01

371

The tof-guard neuromuscular transmission monitor and its use in horses O monitor da transmissão neuromuscular "tof-guard" e seu uso em eqüinos  

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Full Text Available It has been emphasized in the human medical literature, that when using a neuromuscular blocking agent, it is of vital importance the monitoring of the neuromuscular block and that these agents should never be used without it. The purpose of this study was to evaluate the use of the neuromuscular transmission monitor TOF-Guard in horses. Twelve horses were randomly assigned whether to receive pancuronium or atracurium as the neuromuscular blocking agent. All horses were pre-medicated with romifidine, anaesthesia induced with diazepam and ketamine and maintenance with halothane. Abolition of spontaneous ventilation was accomplished by the administration of atracurium or pancuronium. The time from injection of the muscle relaxant agent to the onset of maximum block (T1=0, recovery of T1 to 25% and the recovery of TOF ratio to 0.7 were recorded, as was the time for recovery of T1 from 25 to 75%. It was concluded that it is very important the neuromuscular transmission monitoring during the use of a nondepolarizing neuromuscular blocking agent, since it provides a safer anaesthetic and surgical procedure with the use of adequate dosages and due to the impossibility of a superficialization of the neuromuscular blockade during a surgical procedure. The TOF-Guard showed to be a good option for neuromuscular monitoring in horses.Quando da utilização de bloqueadores neuromusculares, já foi enfatizado na literatura médica humana, que é de vital imporância a monitoração do bloqueio neuromuscular e que estes agentes nunca devem ser utilizados sem a mesma. O objetivo deste estudo foi o de avaliar o uso do monitor da transmissão neuromuscular TOF-Guard em eqüinos. Para tanto, doze eqüinos foram separados aleatoriamente para receberem como bloqueadores neuromusculares o pancurônio ou o atracúrio. Todos os eqüinos foram pré-medicados com romifidina, induzidos com diazepam e quetamina e mantidos com halotano. Foi administrado o atracúrio ou o pancurônio, seguindo-se a apnéia e início da ventilação mecânica controlada. O tempo entre a administração do relaxante muscular e a obtenção de um bloqueio máximo (T1=0, o retorno do T1 para 25% e da razão do TOF para 0,7 e o tempo do retorno do T1 de 25 para 75% foram mensurados. Concluiu-se que é de grande importância a monitoração do bloqueio neuromuscular quando da utilização de um bloqueador neuromuscular não-despolarizante, uma vez que ela torna o ato anestésico e cirúrgico mais seguro, com a utilização de doses adequadas que inviabilizam a superficialização do bloqueio durante o procedimento cirúrgico. O monitor TOF-Guard mostrou ser uma boa opção para a monitoração do bloqueio neuromuscular em eqüinos.

Juliana Noda Bechara

1999-03-01

372

Kinematics Design of a Planar Parallel Controllable Mechanism Based on Particle Swarm Optimization Algorithm  

OpenAIRE

Planar parallel controllable mechanism, which is a combination of two types of motor and mechanism, has better flexible transmission behavior. In this paper, the kinematics analysis for a planar parallel controllable five-bar mechanism is introduced. In order to improve kinematic performance of the controllable mechanism, an optimization design for the mechanism is performed with reference to kinematics objective function. A hybrid optimization algorithm which combines Particle Swarm Optimiza...

Ke Zhang; Shengze Wang

2011-01-01

373

Morphometric and Morphological Analysis of Neuromuscular Junction Alterations in the Denervated Rat Diaphragm / Evaluación de las Alteraciones Morfológicas y Morfométricas de las Uniones Neuromusculares del Diafragma Denervado en Ratas  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish En este trabajo se estudiaron las alteraciones morfológicas y estructurales de las uniones neuromusculares en el diafragma denervado de ratas. Se utilizaron 15 ratas albinas (Rattus norvegicus), machos, adultos, con peso promedio de 200g y cerca de 60 días de edad. Los diafragmas crónicamente denerv [...] ados fueron obtenidos y los animales se sacrificaron después de 4, 8 y 12 semanas de denervación. El antímero izquierdo del diafragma fue denervado por sección del nervio frénico y el antímero derecho fue utilizado como control. Cada antímero fue dividido en 3 fragmentos: uno fue utilizado para el estudio histoquímico (esterasa inespecífica) y morfométrico. Los otros dos se destinaron al estudio de microscopía electrónica de transmisión (MET) y microscopia electrónica de barrido (MEB) de las uniones neuromusculares. El estudio histoquímico de las uniones neuromusculares posterior a la denervación, muestra que la morfología de esas uniones sufre pequeñas alteraciones. Con la evolución del tiempo de denervación esas uniones muestran tamaños menores, son alargadas y con contornos menos nítidos. La ultra-estructura de las uniones neuromusculares después de 12 semanas, demostró que la superficie de la fibra muscular exhibe pliegues de unión más o menos organizados. La región del citoplasma de unión exhibe alteraciones importantes, con degeneración mitocondrial y presencia de muchos filamentos. En MEB se observa que los botones sinápticos primarios son profundos, presentan escavaciones periféricas donde estaban alojados los botones de las terminaciones nerviosas y exhiben internamente, los espacios sinápticos secundarios presentes entre los pliegues de unión del sarcolema. Este estudio mostró que algunos patrones morfológicos demostrados en otros músculos estriados esqueléticos denervados no se repiten con la misma intensidad y curso temporal en el diafragma de ratas. Abstract in english The morphological and structural alterations that occur in the neuromuscular junctions of the denervated rat diaphragm were studied. Fifteen adult male albino rats (Rattus norvegicus) aged about 60 days and with a mean weight of 200 g were used. Chronically denervated diaphragms were obtained and th [...] e animals were sacrificed after 4, 8 and 12 weeks of denervation. The left antimere of the diaphragm was denervated by section of the phrenic nerve and the right antimere was used as control. Each antimere was divided into three fragments: one was used for histochemical (nonspecific esterase) and morphometric study of neuromuscular junctions, and the other two were used for transmission and scanning electron microscopy (SEM) analysis. Histochemical analysis of the diaphragm neuromuscular junctions after denervation showed only small changes in junction morphology. However, these junctions became smaller and elongated and presented less visible contours with increasing time of denervation. Ultrastructural analysis of neuromuscular junctions after 12 weeks showed more or less organized junctional folds on the muscle fiber surface. The junctional cytoplasm exhibited important alterations such as mitochondrial degeneration and the presence of numerous filaments. SEM revealed the presence of deep primary synaptic grooves with peripheral excavations which housed the nerve terminal boutons and exhibited internally the secondary synaptic clefts present among the junctional folds of the sarcolemma. This study showed that some of the morphological changes demonstrated in other denervated striated skeletal muscles are not repeated at the same intensity or in the same temporal pattern in the rat diaphragm.

M. M, Torrejais; J. C, Soares; S. M. M, Matheus; J. M, Mello; L. A. D, Francia-Farje; E. J. D, Vicente.

1235-12-01

374

Pharmacokinetics, neuromuscular effects, and biodisposition of 3-desacetylvecuronium (Org 7268) in cats.  

Science.gov (United States)

The pharmacokinetics, biodisposition, and neuromuscular blocking properties of 3-desacetylvecuronium were studied in 17 adult cats. Animals were divided into three groups: five cats with kidney failure induced by bilateral ligation of the renal pedicles, six cats with galactosamine-induced fulminant hepatitis, and six control cats. An intravenous bolus of 300 micrograms.kg-1 of 3-desacetylvecuronium was rapidly injected into the jugular vein. Arterial blood, urine, and bile samples were collected at regular intervals for 6 h in control cats and for 8 h in cats with kidney or liver failure. The liver was excised for analysis at the end of the experiment. In cats with renal failure, 3-desacetylvecuronium pharmacokinetic and pharmacodynamic variables did not differ from those in control cats. In cats with liver failure, plasma clearance was significantly less and mean residence time greater than in control cats (2.8 +/- 0.6 vs. 14.1 +/- 6.5 ml.kg-1.min-1 and 334 +/- 225 vs. 49 +/- 29 min, mean +/- SD, respectively). Volume of distribution at steady state in cats with liver failure and in control cats was not different. Also, in cats with liver failure, the duration of action and recovery index of 3-desacetylvecuronium was significantly greater than in control cats (168 +/- 62 vs. 82 +/- 32 min, and 39 +/- 19 vs. 10 +/- 4 min, respectively). Onset time of neuromuscular blockade was similar in all three groups. Total recovery of 3-desacetylvecuronium, for all three groups, in urine, bile, and liver was 90 +/- 11% (mean +/- SD). In control cats, 70 +/- 18% of 3-desacetylvecuronium was recovered in bile and liver and 19 +/- 14% in urine. No 3,17-bidesacetylvecuronium (a putative 3-desacetylvecuronium metabolite) was detected.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1675040

Segredo, V; Shin, Y S; Sharma, M L; Gruenke, L D; Caldwell, J E; Khuenl-Brady, K S; Agoston, S; Miller, R D

1991-06-01

375

Anormalidades neuromuscular no desuso, senilidade e caquexia / Neuromuscular abnormalities in disuse, cachexia and ageing  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 oc [...] orrendo 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. Abstract in english 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 denerva [...] tion; 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-vation; the number of motor units diminishes in sixties without any denervation electric activity; there is also reduction on the amount of ACh release on terminal neurons and mitochondrial oxidative capacity leading to compensatory type I muscle fiber number increase. Cachexia also induces reduction on muscle fibers diameter first on legs and then on arms and trunk; there is type II atrophy with occasional angular fibers, RNA/proteic synthesis reduction and normal DNA.

João Aris, Kouyoumdjian.

1993-09-01

376

Sleep polygraphic parameters in neuromuscular diseases / Parâmetros poligráficos do sono em doenças neuromusculares  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Estudando 32 pacientes com doenças neuromusculares -22 com forma de distrofia muscular, 3 com forma de miopatia congênita, 4 com forma de atrofia muscular espinal, 1 com forma recorrente de polimiosite e 1 com síndrome de osteogenesis imperfecta - dos quais 21 estavam impossibilitados de deambulação [...] , distúrbios respiratórios relacionados ao sono foram observados sob forma dessaturação da oxi-hemogloblina, arritmia cardíaca, taquipnéia, taquicardia e roncos. Nove desses 32 pacientes apresentaram períodos de dessaturação de oxi-hemoglobina maiores que 4% em relação aos níveis obtidos em vigília e repouso. Esse grupo de pacientes era caracterizado por apresentar síndrome respiratória restritiva associada a deformidade torácica (principalmente escoliose). Alguns apresenta