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1

Molecular control of neuromuscular junction development.  

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Skeletal muscle innervation is a multi-step process leading to the neuromuscular junction (NMJ) apparatus formation. The transmission of the signal from nerve to muscle occurs at the NMJ level. The molecular mechanism that orchestrates the organization and functioning of synapses is highly complex, and it has not been completely elucidated so far. Neuromuscular junctions are assembled on the muscle fibers at very precise locations called end plates (EP). Acetylcholine receptor (AChR) clusterization at the end plates is required for an accurate synaptic transmission. This review will focus on some mechanisms responsible for accomplishing the correct distribution of AChRs at the synapses. Recent evidences support the concept that a dual transcriptional control of AChR genes in subsynaptic and extrasynaptic nuclei is crucial for AChR clusterization. Moreover, new players have been discovered in the agrin-MuSK pathway, the master organizer of postsynaptical differentiation. Mutations in this pathway cause neuromuscular congenital disorders. Alterations of the postynaptic apparatus are also present in physiological conditions characterized by skeletal muscle wasting. Indeed, recent evidences demonstrate how NMJ misfunctioning has a crucial role at the onset of age-associated sarcopenia. PMID:22450265

Ferraro, Elisabetta; Molinari, Francesca; Berghella, Libera

2012-03-01

2

Molecular control of neuromuscular junction development  

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Skeletal muscle innervation is a multi-step process leading to the neuromuscular junction (NMJ) apparatus formation. The transmission of the signal from nerve to muscle occurs at the NMJ level. The molecular mechanism that orchestrates the organization and functioning of synapses is highly complex, and it has not been completely elucidated so far. Neuromuscular junctions are assembled on the muscle fibers at very precise locations called end plates (EP). Acetylcholine receptor (AChR) clusteri...

Ferraro, Elisabetta; Molinari, Francesca; Berghella, Libera

2012-01-01

3

NEUROMUSCULAR CONTROL IN LUMBAR DISORDERS  

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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

4

NEUROMUSCULAR CONTROL IN LUMBAR DISORDERS  

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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

5

[Molecular mechanisms underlying the formation of neuromuscular junction].  

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The neuromuscular junction (NMJ) is a synapse between a motor neuron and skeletal muscle. The contraction of skeletal muscle is controlled by the neurotransmitter acetylcholine (ACh), which is released from the motor nerve terminal. To achieve efficient neuromuscular transmission, acetylcholine receptors (AChRs) must be densely clustered on the muscle membrane of the NMJ. Failure of AChR clustering is associated with disorders of neuromuscular transmission such as congenital myasthenic syndromes (CMS) and myasthenia gravis (MG). Motoneuronal agrin and muscle-specific receptor tyrosine kinase (MuSK) are known to play essential roles in the formation and maintenance of NMJs in the central region of each muscle. However, it had been unclear how agrin activates MuSK. Recent studies have elucidated the roles of several key molecules, including the cytoplasmic adaptor protein Dok-7 and LDL receptor-related protein 4 (Lrp4), in agrin-induced MuSK activation. Moreover, new evidence indicates that cyclin-dependent kinase 5 (Cdk5) regulates postsynaptic differentiation. In this review, we summarize the latest developments in molecular mechanisms underlying NMJ formation in vertebrates. PMID:21747134

Higuchi, Osamu; Yamanashi, Yuji

2011-07-01

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Drosophila Nesprin-1 controls glutamate receptor density at neuromuscular junctions.  

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Nesprin-1 is a core component of a protein complex connecting nuclei to cytoskeleton termed LINC (linker of nucleoskeleton and cytoskeleton). Nesprin-1 is anchored to the nuclear envelope by its C-terminal KASH domain, the disruption of which has been associated with neuronal and neuromuscular pathologies, including autosomal recessive cerebellar ataxia and Emery-Dreifuss muscular dystrophy. Here, we describe a new and unexpected role of Drosophila Nesprin-1, Msp-300, in neuromuscular junction. We show that larvae carrying a deletion of Msp-300 KASH domain (Msp-300 (?KASH) ) present a locomotion defect suggestive of a myasthenia, and demonstrate the importance of muscle Msp-300 for this phenotype, using tissue-specific RNAi knock-down. We show that Msp-300 (?KASH) mutants display abnormal neurotransmission at the larval neuromuscular junction, as well as an imbalance in postsynaptic glutamate receptor composition with a decreased percentage of GluRIIA-containing receptors. We could rescue Msp-300 (?KASH) locomotion phenotypes by GluRIIA overexpression, suggesting that the locomotion impairment associated with the KASH domain deletion is due to a reduction in junctional GluRIIA. In summary, we found that Msp-300 controls GluRIIA density at the neuromuscular junction. Our results suggest that Drosophila is a valuable model for further deciphering how Nesprin-1 and LINC disruption may lead to neuronal and neuromuscular pathologies. PMID:24492984

Morel, Véronique; Lepicard, Simon; Rey, Alexandre N; Parmentier, Marie-Laure; Schaeffer, Laurent

2014-09-01

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Invasive home mechanical ventilation, mainly focused on neuromuscular disorders  

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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

8

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

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

Bruno, Paul

2014-06-01

9

Synaptic dynamics at the neuromuscular junction: mechanisms and models.  

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During development, the neuromuscular junction passes through a stage of extensive polyinnervation followed by a period of wholesale synapse elimination. In this report we discuss mechanisms and interactions that could mediate many of the key aspects of these important developmental events. Our emphasis is on (1) establishing an overall conceptual framework within which the role of many distinct cellular interactions and molecular factors can be evaluated, and (2) generating computer simulations that systematically test the adequacy of different models in accounting for a wide range of biological data. Our analysis indicates that several relatively simple mechanisms are each capable of explaining a variety of experimental observations. On the other hand, no one mechanism can account for the full spectrum of experimental results. Thus, it is important to consider models that are based on interactions among multiple mechanisms. A potentially powerful combination is one based on (1) a scaffold within the basal lamina or in the postsynaptic membrane which is induced by nerve terminals and which serves to stabilize terminals by a positive feedback mechanism; (2) a sprouting factor whose release by muscle fibers is down-regulated by activity and perhaps other factors; and (3) an intrinsic tendency of motor neurons to withdraw some connections while allowing others to grow. PMID:2181065

Van Essen, D C; Gordon, H; Soha, J M; Fraser, S E

1990-01-01

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Tai Chi and vestibular rehabilitation improve vestibulopathic gait via different neuromuscular mechanisms: Preliminary report  

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Full Text Available Abstract Background Vestibular rehabilitation (VR is a well-accepted exercise program intended to remedy balance impairment caused by damage to the peripheral vestibular system. Alternative therapies, such as Tai Chi (TC, have recently gained popularity as a treatment for balance impairment. Although VR and TC can benefit people with vestibulopathy, the degree to which gait improvements may be related to neuromuscular adaptations of the lower extremities for the two different therapies are unknown. Methods We examined the relationship between lower extremity neuromuscular function and trunk control in 36 older adults with vestibulopathy, randomized to 10 weeks of either VR or TC exercise. Time-distance measures (gait speed, step length, stance duration and step width, lower extremity sagittal plane mechanical energy expenditures (MEE, and trunk sagittal and frontal plane kinematics (peak and range of linear and angular velocity, were measured. Results Although gait time-distance measures were improved in both groups following treatment, no significant between-groups differences were observed for the MEE and trunk kinematic measures. Significant within groups changes, however, were observed. The TC group significantly increased ankle MEE contribution and decreased hip MEE contribution to total leg MEE, while no significant changes were found within the VR group. The TC group exhibited a positive relationship between change in leg MEE and change in trunk velocity peak and range, while the VR group exhibited a negative relationship. Conclusion Gait function improved in both groups consistent with expectations of the interventions. Differences in each group's response to therapy appear to suggest that improved gait function may be due to different neuromuscular adaptations resulting from the different interventions. The TC group's improvements were associated with reorganized lower extremity neuromuscular patterns, which appear to promote a faster gait and reduced excessive hip compensation. The VR group's improvements, however, were not the result of lower extremity neuromuscular pattern changes. Lower-extremity MEE increases corresponded to attenuated forward trunk linear and angular movement in the VR group, suggesting better control of upper body motion to minimize loss of balance. These data support a growing body of evidence that Tai Chi may be a valuable complementary treatment for vestibular disorders.

Parker Stephen W

2005-02-01

11

Effects of neuromuscular lags on controlling contact transitions.  

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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 (tau(m)) are different from those for producing static force vectors (tau(f)). We previously described the neural control of such abrupt transitions in humans, and found that unavoidable errors arise because sensorimotor time delays and lags prevent an instantaneous switch between different torques. Here, we use numerical optimization on a finger model to reveal physical bounds for controlling such rapid contact transitions. Resembling human data, it is necessary to anticipatorily switch joint torques to tau(f )at about 30 ms before contact to minimize the initial misdirection of the fingertip force vector. This anticipatory strategy arises in our deterministic model from neuromuscular lags, and not from optimizing for robustness to noise/uncertainties. Importantly, the optimal solution also leads to a trade-off between the speed of force magnitude increase versus the accuracy of initial force direction. This is an alternative to prevailing theories that propose multiplicative noise in muscles as the driver of speed-accuracy trade-offs. We instead find that the speed-accuracy trade-off arises solely from neuromuscular lags. Finally, because our model intentionally uses idealized assumptions, its agreement with human data suggests that the biological system is controlled in a way that approaches the physical boundaries of performance. PMID:19218157

Venkadesan, Madhusudhan; Valero-Cuevas, Francisco J

2009-03-28

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Sensory-motor control of ligaments and associated neuromuscular disorders.  

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The ligaments were considered, over several centuries, as the major restraints of the joints, keeping the associated bones in position and preventing instability, e.g. their separation from each other and/or mal-alignment. This project, conducted over 25 years, presents the following hypothesis: 1. Ligaments are also major sensory organs, capable of monitoring relevant kinesthetic and proprioceptive data. 2. Excitatory and inhibitory reflex arcs from sensory organs within the ligaments recruit/de-recruit the musculature to participate in maintaining joint stability as needed by the movement type performed. 3. The synergy of the ligament and associated musculature allocates prominent role for muscles in maintaining joint stability. 4. The viscoelastic properties of ligaments and their classical responses to static and cyclic loads or movements such as creep, tension-relaxation, hysteresis and strain rate dependence decreases their effectiveness as joint restraint and stabilizers and as sensory organs and exposes the joint to injury. 5. Long-term exposure of ligaments to static or cyclic loads/movements in a certain dose-duration paradigms consisting of high loads, long loading duration, high number of load repetitions, high frequency or rate of loading and short rest periods develops acute inflammatory responses which require long rest periods to resolve. These inflammatory responses are associated with a temporary (acute) neuromuscular disorder and during such period high exposure to injury is present. 6. Continued exposure of an inflamed ligament to static or cyclic load may result in a chronic inflammation and the associated chronic neuromuscular disorder known as cumulative trauma disorder (CTD). 7. The knowledge gained from basic and applied research on the sensory - motor function of ligaments can be used as infrastructure for translational research; mostly for the development of "smart orthotic" systems for ligament deficient patients. Three such "smart orthosis", for the knee and lumbar spine are described. 8. The knowledge gained from the basic and applied research manifests in new physiotherapy modalities for ligament deficient patients. Ligaments, therefore, are important structures with significant impact on motor control and a strong influence on the quality of movement, safety/stability of the joint and potential disorders that impact the safety and health of workers and athletes. PMID:17045488

Solomonow, M

2006-12-01

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Simulation of a functional neuromuscular stimulation powered mechanical gait orthosis with coordinated joint locking.  

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The purpose of this study was to examine a hybrid orthosis system (HOS) for walking after spinal-cord injury (SCI) that coordinates the mechanical locking and unlocking of knee and ankle joints of a reciprocating gait orthosis (RGO), while propulsive forces are injected and unlocked joints controlled with functional neuromuscular stimulation (FNS). The likely effectiveness of the HOS in terms of forward progression, stability, and posture of paraplegic gait was determined in this simulation study. A three-dimensional computer model of a HOS combining FNS with an RGO incorporating feedback control of muscle activation and joint locking was developed. An anthropomorphic human model included passive joint moments and a foot-ground contact model adapted from other studies. A model of the RGO reciprocally coupled the hips and locked and unlocked the knee and ankle joints during stance and swing respectively. The actions of muscles under FNS activation were modeled via closed-loop control of joint torque inputs. A walking aid that mimicked canes and voluntary upper extremity actions maintained lateral stability by providing the necessary shoulder forces and moments. The simulated HOS achieved gait speeds of 0.51 +/- 0.03 m/s, stride lengths of 0.85 +/- 0.04 m, and cadences of 72 +/- 4 steps/min, exceeding the reported performance of other assistive gait systems. Although minimal forward trunk tilt was found to be necessary during specific phases of gait, posture, and stability were significantly improved over FNS-only systems. PMID:16003904

To, Curtis S; Kirsch, Robert F; Kobetic, Rudi; Triolo, Ronald J

2005-06-01

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Hormonal and Neuromuscular Responses to Mechanical Vibration Applied to Upper Extremity Muscles  

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Objective To investigate the acute residual hormonal and neuromuscular responses exhibited following a single session of mechanical vibration applied to the upper extremities among different acceleration loads. Methods Thirty male students were randomly assigned to a high vibration group (HVG), a low vibration group (LVG), or a control group (CG). A randomized double-blind, controlled-parallel study design was employed. The measurements and interventions were performed at the Laboratory of Biomechanics of the University of L'Aquila. The HVG and LVG participants were exposed to a series of 20 trials ×10 s of synchronous whole-body vibration (WBV) with a 10-s pause between each trial and a 4-min pause after the first 10 trials. The CG participants assumed an isometric push-up position without WBV. The outcome measures were growth hormone (GH), testosterone, maximal voluntary isometric contraction during bench-press, maximal voluntary isometric contraction during handgrip, and electromyography root-mean-square (EMGrms) muscle activity (pectoralis major [PM], triceps brachii [TB], anterior deltoid [DE], and flexor carpi radialis [FCR]). Results The GH increased significantly over time only in the HVG (P?=?0.003). Additionally, the testosterone levels changed significantly over time in the LVG (P?=?0.011) and the HVG (P?=?0.001). MVC during bench press decreased significantly in the LVG (P?=?0.001) and the HVG (P?=?0.002). In the HVG, the EMGrms decreased significantly in the TB (P?=?0.006) muscle. In the LVG, the EMGrms decreased significantly in the DE (P?=?0.009) and FCR (P?=?0.006) muscles. Conclusion Synchronous WBV acutely increased GH and testosterone serum concentrations and decreased the MVC and their respective maximal EMGrms activities, which indicated a possible central fatigue effect. Interestingly, only the GH response was dependent on the acceleration with respect to the subjects' responsiveness. PMID:25368995

Di Giminiani, Riccardo; Fabiani, Leila; Baldini, Giuliano; Cardelli, Giovanni; Giovannelli, Aldo; Tihanyi, Jozsef

2014-01-01

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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

16

Optimality in neuromuscular systems.  

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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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The Role of Neuromuscular Changes in Aging and Knee Osteoarthritis on Dynamic Postural Control  

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Knee osteoarthritis (OA) is a chronic joint condition, with 30% of those over the age of 75 exhibiting severe radiographic disease. Nearly 50% of those with knee OA have experienced a fall in the past year. Falls are a considerable public health concern, with a high risk of serious injury and a significant socioeconomic impact. The ability to defend against a fall relies on adequate dynamic postural control, and alterations in dynamic postural control are seen with normal aging. Neuromuscular...

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

2013-01-01

18

Controlled pilot study of the effects of neuromuscular therapy in patients with Parkinson's disease.  

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The objectives of this study is to examine the effects of neuromuscular therapy (NMT) on motor and nonmotor symptoms in Parkinson's disease (PD). Thirty-six subjects with PD were randomly assigned to NMT or music relaxation (MR, or active control). Subjects received treatment twice a week for 4 weeks. Testing was conducted at baseline, after final treatment, and 8 days after final treatment. Primary outcome measures were the Motor subscale of the United Parkinson Disease Rating Scale (UPDRS) and the Clinical Global Impression scale (CGI-Change). Secondary outcome measures included a PD-specific quality of life scale (PDQ-39), quantitative measures of motor function, and severity scales for anxiety and depression symptoms. NMT resulted in a significant and sustained improvement in the Motor subscale of the UPDRS (P mood (P = 0.001) and anxiety (P = 0.002), whereas NMT had no effect on mood (P = 0.09), and its initial effect on anxiety (P = 0.0009) dissipated after 8 days (P = 0.40). Group differences for UPDRS motor score and patient CGI-Change were superior in the NMT compared to the MR group. There was no group difference in PDQ-39 scores or in nonmotor measures. The findings suggest that NMT can improve motor and selected nonmotor symptoms in PD and that this effect is more durable for the motor symptoms. The results of this pilot study warrant larger controlled studies to examine dose range, durability, and mechanisms of NMT in PD function. PMID:17044088

Craig, Lauren H; Svircev, Anna; Haber, Michael; Juncos, Jorge L

2006-12-01

19

ALS as a distal axonopathy: molecular mechanisms affecting neuromuscular junction stability in the presymptomatic stages of the disease.  

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Amyotrophic Lateral Sclerosis (ALS) is being redefined as a distal axonopathy, in that many molecular changes influencing motor neuron degeneration occur at the neuromuscular junction (NMJ) at very early stages of the disease prior to symptom onset. A huge variety of genetic and environmental causes have been associated with ALS, and interestingly, although the cause of the disease can differ, both sporadic and familial forms of ALS show a remarkable similarity in terms of disease progression and clinical manifestation. The NMJ is a highly specialized synapse, allowing for controlled signaling between muscle and nerve necessary for skeletal muscle function. In this review we will evaluate the clinical, animal experimental and cellular/molecular evidence that supports the idea of ALS as a distal axonopathy. We will discuss the early molecular mechanisms that occur at the NMJ, which alter the functional abilities of the NMJ. Specifically, we focus on the role of axon guidance molecules on the stability of the cytoskeleton and how these molecules may directly influence the cells of the NMJ in a way that may initiate or facilitate the dismantling of the neuromuscular synapse in the presymptomatic stages of ALS. PMID:25177267

Moloney, Elizabeth B; de Winter, Fred; Verhaagen, Joost

2014-01-01

20

ALS as a distal axonopathy: molecular mechanisms affecting neuromuscular junction stability in the presymptomatic stages of the disease  

Science.gov (United States)

Amyotrophic Lateral Sclerosis (ALS) is being redefined as a distal axonopathy, in that many molecular changes influencing motor neuron degeneration occur at the neuromuscular junction (NMJ) at very early stages of the disease prior to symptom onset. A huge variety of genetic and environmental causes have been associated with ALS, and interestingly, although the cause of the disease can differ, both sporadic and familial forms of ALS show a remarkable similarity in terms of disease progression and clinical manifestation. The NMJ is a highly specialized synapse, allowing for controlled signaling between muscle and nerve necessary for skeletal muscle function. In this review we will evaluate the clinical, animal experimental and cellular/molecular evidence that supports the idea of ALS as a distal axonopathy. We will discuss the early molecular mechanisms that occur at the NMJ, which alter the functional abilities of the NMJ. Specifically, we focus on the role of axon guidance molecules on the stability of the cytoskeleton and how these molecules may directly influence the cells of the NMJ in a way that may initiate or facilitate the dismantling of the neuromuscular synapse in the presymptomatic stages of ALS.

Moloney, Elizabeth B.; de Winter, Fred; Verhaagen, Joost

2014-01-01

 
 
 
 
21

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

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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

22

Doenças neuromusculares Neuromuscular disorders  

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Full Text Available Objetivo: apresentar os dados essenciais para o diagnóstico diferencial entre as principais doenças neuromusculares, denominação genérica sob a qual agrupam-se diferentes afecções, decorrentes do acometimento primário da unidade motora (motoneurônio medular, raiz nervosa, nervo periférico, junção mioneural e músculo. Fontes dos dados: os aspectos clínicos fundamentais para estabelecer o diagnóstico diferencial entre as diferentes doenças neuromusculares, bem como entre estas e as causas de hipotonia muscular secundária ao comprometimento do sistema nervoso central ou a doenças sistêmicas não-neurológicas, são enfatizados, com base na experiência clínica vinda do atendimento a crianças com doenças neuromusculares durante os últimos 12 anos, no ambulatório de doenças neuromusculares do Hospital das Clínicas da Faculdade de Medicina, da Universidade de São Paulo. A revisão bibliográfica foi efetuada através do Medline e do periódico Neuromuscular Disorders, publicação oficial da World Muscle Society. Síntese dos dados: nas crianças, a maior parte destas afecções é geneticamente determinada, sendo as mais comuns a distrofia muscular progressiva ligada ao sexo, de Duchenne, a amiotrofia espinal infantil, a distrofia muscular congênita, a distrofia miotônica de Steinert, e as miopatias congênitas, estruturais e não estruturais. Polineuropatias hereditárias, síndrome miastênica congênita e miopatias metabólicas são menos comuns, porém mostram correlação geno-fenotípica cada vez mais precisa. Conclusões: na década passada, inúmeros avanços da genética molecular facilitaram imensamente o diagnóstico e o aconselhamento genético das doenças neuromusculares mais comuns das crianças, inclusive possibilitando diagnóstico fetal e, adicionalmente, vieram permitir melhor caracterização fenotípica e classificação mais objetiva.Objective: to discuss the most important aspects for performing a differential diagnosis among the main neuromuscular disorders in children, that include the diseases affecting the motor unity, i.e. spinal motor neurons, peripheral nerves, neuromuscular junction and muscular fibers. Sources: the review of the clinical aspects that should be considered for a prompt differential diagnosis among several neuromuscular disorders as well as between those and the main causes of secondary muscular hypotonia due to central nervous system or systemic disturbances is based on the clinical experience acquired along the last 12 years in following-up children with Neuromuscular Disorders attended at the outpatient Service of Neuromuscular Disorders at the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. In addition, it is based on Medline and on the review of the most recent numbers of Neuromuscular Disorders, the official journal of the World Muscle Society. Summary of the findings: most of neuromuscular disorders are genetic conditions in children and the most common of them are X-linked Progressive Muscular Dystrophy of Duchenne, Spinal Muscular Atrophy, Congenital Muscular Dystrophy, Myotonic Dystrophy and Congenital Myopathies. Conclusions: due to the phenomenal development in human molecular genetics the pathogenesis of several neuromuscular disorders in children has been clarified over the last decade. Nowadays many new diagnostic methods, including techniques of fetal diagnosis, and a more objective genotype-phenotype correlation as well as classification are available.

Umbertina C. Reed

2002-08-01

23

Doenças neuromusculares / Neuromuscular disorders  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Objetivo: apresentar os dados essenciais para o diagnóstico diferencial entre as principais doenças neuromusculares, denominação genérica sob a qual agrupam-se diferentes afecções, decorrentes do acometimento primário da unidade motora (motoneurônio medular, raiz nervosa, nervo periférico, junção mi [...] oneural e músculo). Fontes dos dados: os aspectos clínicos fundamentais para estabelecer o diagnóstico diferencial entre as diferentes doenças neuromusculares, bem como entre estas e as causas de hipotonia muscular secundária ao comprometimento do sistema nervoso central ou a doenças sistêmicas não-neurológicas, são enfatizados, com base na experiência clínica vinda do atendimento a crianças com doenças neuromusculares durante os últimos 12 anos, no ambulatório de doenças neuromusculares do Hospital das Clínicas da Faculdade de Medicina, da Universidade de São Paulo. A revisão bibliográfica foi efetuada através do Medline e do periódico Neuromuscular Disorders, publicação oficial da World Muscle Society. Síntese dos dados: nas crianças, a maior parte destas afecções é geneticamente determinada, sendo as mais comuns a distrofia muscular progressiva ligada ao sexo, de Duchenne, a amiotrofia espinal infantil, a distrofia muscular congênita, a distrofia miotônica de Steinert, e as miopatias congênitas, estruturais e não estruturais. Polineuropatias hereditárias, síndrome miastênica congênita e miopatias metabólicas são menos comuns, porém mostram correlação geno-fenotípica cada vez mais precisa. Conclusões: na década passada, inúmeros avanços da genética molecular facilitaram imensamente o diagnóstico e o aconselhamento genético das doenças neuromusculares mais comuns das crianças, inclusive possibilitando diagnóstico fetal e, adicionalmente, vieram permitir melhor caracterização fenotípica e classificação mais objetiva. Abstract in english Objective: to discuss the most important aspects for performing a differential diagnosis among the main neuromuscular disorders in children, that include the diseases affecting the motor unity, i.e. spinal motor neurons, peripheral nerves, neuromuscular junction and muscular fibers. Sources: the rev [...] iew of the clinical aspects that should be considered for a prompt differential diagnosis among several neuromuscular disorders as well as between those and the main causes of secondary muscular hypotonia due to central nervous system or systemic disturbances is based on the clinical experience acquired along the last 12 years in following-up children with Neuromuscular Disorders attended at the outpatient Service of Neuromuscular Disorders at the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. In addition, it is based on Medline and on the review of the most recent numbers of Neuromuscular Disorders, the official journal of the World Muscle Society. Summary of the findings: most of neuromuscular disorders are genetic conditions in children and the most common of them are X-linked Progressive Muscular Dystrophy of Duchenne, Spinal Muscular Atrophy, Congenital Muscular Dystrophy, Myotonic Dystrophy and Congenital Myopathies. Conclusions: due to the phenomenal development in human molecular genetics the pathogenesis of several neuromuscular disorders in children has been clarified over the last decade. Nowadays many new diagnostic methods, including techniques of fetal diagnosis, and a more objective genotype-phenotype correlation as well as classification are available.

Umbertina C., Reed.

2002-08-01

24

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

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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

25

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

Science.gov (United States)

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. Our focus here is on control of fast-running locomotion. A key observation emerging from studies of steady level locomotion is that simple spring-mass dynamics, which help to economize energy expenditure, also apply to stabilization of unsteady running. Spring-mass dynamics apply to conditions that involve lateral impulsive perturbations, sudden changes in terrain height, and sudden changes in substrate stiffness or damping. Experimental investigation of unsteady locomotion is challenging, however, due to the variability inherent in such behaviors. Another emerging principle is that initial conditions associated with postural changes following a perturbation define different context-dependent stabilization responses. Distinct stabilization modes following a perturbation likely result from proximo-distal differences in limb muscle architecture, function and control strategy. Proximal muscles may be less sensitive to sudden perturbations and appear to operate, in such circumstances, under feed-forward control. In contrast, multiarticular distal muscles operate, via their tendons, to distribute energy among limb joints in a manner that also depends on the initial conditions of limb contact with the ground. Intrinsic properties of these distal muscle-tendon elements, in combination with limb and body dynamics, appear to provide rapid initial stabilizing mechanisms that are often consistent with spring-mass dynamics. These intrinsic mechanisms likely help to simplify the neural control task, in addition to compensating for delays inherent to subsequent force- and length-dependent neural feedback. Future work will benefit from integrative biomechanical approaches that employ a combination of modeling and experimental techniques to understand how the elegant interplay of intrinsic muscle properties, body dynamics and neural control allows animals to achieve stability and agility over a variety of conditions. PMID:17704070

Biewener, Andrew A; Daley, Monica A

2007-09-01

26

Predictive algorithms for neuromuscular control of human locomotion.  

Science.gov (United States)

The problem of quantifying muscular activity of the human body can be formulated as an optimal control problem. The current methods used with large-scale biomechanical systems are non-derivative techniques. These methods are costly, as they require numerous integrations of the equations of motion. Additionally, the convergence is slow, making them impractical for use with large systems. We apply an efficient numerical algorithm to the biomechanical optimal control problem. Using direct collocation with a trapezoidal discretization, the equations of motion are converted into a set of algebraic constraint equations. An augmented Lagrangian formulation is used for the optimization problem to handle both equality and inequality constraints. The resulting min-max problem is solved with a generalized Newton method. In contrast to the prevalent optimal control implementations, we calculate analytical first- and second-derivative information and obtain local quadratic convergence. To demonstrate the efficacy of the method, we solve a steady-state pedaling problem with 7 segments and 18 independent muscle groups. The computed muscle activations compare well with experimental EMG data. The computational effort is significantly reduced and solution times are a fraction of those of the non-derivative techniques. PMID:11448699

Kaplan, M L; Heegaard, J H

2001-08-01

27

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

28

No effect on performance tests from a neuromuscular warm-up programme in youth female football: a randomised controlled trial  

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The objective of the present randomised controlled trial was to study the effect of a neuromuscular warm-up programme on performance tests in youth female football. less thanbrgreater than less thanbrgreater thanFour youth female football teams with players aged 12-16 years were randomised into an intervention group and control group. The intervention was a 15-min neuromuscular warm-up programme carried out twice a week during the 11-week study period. Baseline and follow-up measurements of p...

Lindblom, Hanna; Walde?n, Markus; Ha?gglund, Martin

2012-01-01

29

The feasibility of a functional neuromuscular stimulation powered mechanical gait orthosis with coordinated joint locking.  

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The purpose of this study was to examine the feasibility of a hybrid orthosis for walking after spinal cord injury (SCI) that coordinates the locking and unlocking of knee and ankle joints of a reciprocating gait orthosis (RGO), while injecting propulsive forces and controlling unlocked joints with functional neuromuscular stimulation (FNS). The effectiveness of the hybrid system relative to gait stability and posture were determined in this simulation study. A three-dimensional computer model of a hybrid orthosis system (HOS) combining FNS with a RGO incorporating feedback control of muscle activation and coordinated joint locking was developed in Working Model 3D. The simulated hybrid orthosis system achieved gait speeds, stride lengths, and cadences of 0.51 +/- 0.03 m/s, 0.85 +/- 0.04 m, and 72 +/- 4 steps/min respectively, exceeding the performance of other hybrid systems. Forward trunk tilt was found to be necessary during initial step from standing and pro-swing, but posture and stability were significantly improved over FNS-only systems. The results of the model shows that a HOS that coordinates knee and ankle joint locking with electrical stimulation to the paralyzed muscles holds significant advantages over brace- and FNS-only walking systems in terms of enhanced trunk stability and posture. PMID:17271186

To, C S; Kirsch, R F; Kobetic, R; Triolo, R J

2004-01-01

30

Estimulação elétrica neuromuscular e o alongamento passivo manual na recuperação das propriedades mecânicas do músculo gastrocnêmio imobilizado / Neuromuscular electric stimulation and manual passive stretching when recovering mechanical properties of immobilized gastrocnemius muscles  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Avaliamos a influência da imobilização, remobilização livre, remobilização com alongamento passivo manual, remobilização com estimulação elétrica neuromuscular (NMES) e remobilização por NMES e alongamento passivo manual associados sobre algumas propriedades mecânicas do músculo gastrocnêmio de rata [...] s. Foram avaliadas 60 ratas divididas em seis grupos.Um destes grupos foi usado como controle. Todos os outros grupos tiveram o membro posterior direito imobilizado por 14 dias consecutivos. Destes grupos um foi imobilizado e em seguida avaliado, um foi liberado da imobilização e permaneceu nas gaiolas plásticas por 10 dias, outro foi submetido a técnica de alongamento passivo manual por 10 dias consecutivos, outro foi submetido a NMES por 10 dias consecutivos e o último foi submetido a NMES somado ao alongamento passivo manual por 10 dias consecutivos. Observamos que a imobilização reduziu os valores das propriedades mecânicas avaliadas no músculo. A remobilização livre não restabeleceu nenhuma das propriedades avaliadas. A remobilização por alongamento passivo manual devolveu ao músculo as propriedades de alongamento no limite de proporcionalidade, rigidez e resiliência. A remobilização estimulada por NMES restabeleceu todas as propriedades estudadas. A remobilização por NMES somada ao alongamento passivo restabeleceu as propriedades mecânicas de alongamento no limite máximo e de proporcionalidade e rigidez. Abstract in english We evaluated the influence of immobilization, free remobilization, remobilization with manual passive stretching, remobilization with neuromuscular electric stimulation (NMES) and remobilization with electric stimulation and associated passive stretching on some mechanical properties of the gastrocn [...] emius muscle of female rats. Sixty female rats were assessed, being distributed into 6 experimental groups. One of these groups served as control. The animals of the five remaining groups had their right posterior limb immobilized for 14 consecutive days. From the five groups, one was sacrificed right after the immobilization period, a second group was released from immobilization, a third was submitted to the manual passive stretching technique for 10 consecutive days, a fourth was submitted to NMES for 10 consecutive days and the last one was submitted to NMES and manual passive stretching for 10 consecutive days. We found that the immobilization caused a significant reduction of the mechanical properties values evaluated on the muscle. The free remobilization could not reestablish any of the properties. The remobilization by manual passive stretching restored the mechanical properties of stretching at the proportionality limit, stiffness and resilience. The remobilization stimulated by NMES reestablished all of studied properties. The remobilization by electric stimulation and passive stretching reestablished the mechanical properties of stretching at the maximum limit, proportionality limit, and stiffness.

Leonardo César, Carvalho; Antonio Carlos, Shimano; Celso Hermínio Ferraz, Picado.

31

Estimulação elétrica neuromuscular e o alongamento passivo manual na recuperação das propriedades mecânicas do músculo gastrocnêmio imobilizado Neuromuscular electric stimulation and manual passive stretching when recovering mechanical properties of immobilized gastrocnemius muscles  

Directory of Open Access Journals (Sweden)

Full Text Available Avaliamos a influência da imobilização, remobilização livre, remobilização com alongamento passivo manual, remobilização com estimulação elétrica neuromuscular (NMES e remobilização por NMES e alongamento passivo manual associados sobre algumas propriedades mecânicas do músculo gastrocnêmio de ratas. Foram avaliadas 60 ratas divididas em seis grupos.Um destes grupos foi usado como controle. Todos os outros grupos tiveram o membro posterior direito imobilizado por 14 dias consecutivos. Destes grupos um foi imobilizado e em seguida avaliado, um foi liberado da imobilização e permaneceu nas gaiolas plásticas por 10 dias, outro foi submetido a técnica de alongamento passivo manual por 10 dias consecutivos, outro foi submetido a NMES por 10 dias consecutivos e o último foi submetido a NMES somado ao alongamento passivo manual por 10 dias consecutivos. Observamos que a imobilização reduziu os valores das propriedades mecânicas avaliadas no músculo. A remobilização livre não restabeleceu nenhuma das propriedades avaliadas. A remobilização por alongamento passivo manual devolveu ao músculo as propriedades de alongamento no limite de proporcionalidade, rigidez e resiliência. A remobilização estimulada por NMES restabeleceu todas as propriedades estudadas. A remobilização por NMES somada ao alongamento passivo restabeleceu as propriedades mecânicas de alongamento no limite máximo e de proporcionalidade e rigidez.We evaluated the influence of immobilization, free remobilization, remobilization with manual passive stretching, remobilization with neuromuscular electric stimulation (NMES and remobilization with electric stimulation and associated passive stretching on some mechanical properties of the gastrocnemius muscle of female rats. Sixty female rats were assessed, being distributed into 6 experimental groups. One of these groups served as control. The animals of the five remaining groups had their right posterior limb immobilized for 14 consecutive days. From the five groups, one was sacrificed right after the immobilization period, a second group was released from immobilization, a third was submitted to the manual passive stretching technique for 10 consecutive days, a fourth was submitted to NMES for 10 consecutive days and the last one was submitted to NMES and manual passive stretching for 10 consecutive days. We found that the immobilization caused a significant reduction of the mechanical properties values evaluated on the muscle. The free remobilization could not reestablish any of the properties. The remobilization by manual passive stretching restored the mechanical properties of stretching at the proportionality limit, stiffness and resilience. The remobilization stimulated by NMES reestablished all of studied properties. The remobilization by electric stimulation and passive stretching reestablished the mechanical properties of stretching at the maximum limit, proportionality limit, and stiffness.

Leonardo César Carvalho

2008-01-01

32

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

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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

33

Tai Chi and vestibular rehabilitation improve vestibulopathic gait via different neuromuscular mechanisms: Preliminary report  

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Abstract Background Vestibular rehabilitation (VR) is a well-accepted exercise program intended to remedy balance impairment caused by damage to the peripheral vestibular system. Alternative therapies, such as Tai Chi (TC), have recently gained popularity as a treatment for balance impairment. Although VR and TC can benefit people with vestibulopathy, the degree to which gait improvements may be related to neuromuscular adaptations of the lower extremities for the two differe...

Parker Stephen W; Krebs David E; McGibbon Chris A; Scarborough Donna M; Wayne Peter M; Wolf Steven L

2005-01-01

34

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

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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...

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

2012-01-01

35

Double-blind controlled trials of Cronassial in chronic neuromuscular diseases and ataxia.  

Science.gov (United States)

We report three 12-month, double-blind, three-phase studies comparing the effect of placebo and 40 mg and 100 mg IM daily of purified bovine brain gangliosides (Cronassial) in chronic neuromuscular diseases. Thirty patients with Charcot-Marie-Tooth disease, 16 with idiopathic polyneuropathy, and 30 with spinocerebellar degeneration had neuromuscular function measured monthly by quantitative testing of motor and sensory function, coordination, and electrophysiologic factors. Analysis of these studies, and of longer term (up to 2 years) open studies of 100 mg daily of Cronassial in 67 patients failed to show therapeutic efficacy of Cronassial. Statistical power calculations indicated that five of the 37 measures had greater than a 70% chance of detecting a 20% difference in the rate of progression of the active-drug and placebo groups. A number of measures significantly improved during prolonged placebo treatment, suggesting that the placebo effect has a strong influence on "objective" measures of neuromuscular function. PMID:2847079

Bradley, W G; Badger, G J; Tandan, R; Fillyaw, M J; Young, J; Fries, T J; Krusinski, P B; Witarsa, M; Boerman, J; Blair, C J

1988-11-01

36

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

37

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  

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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.

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

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Full Text Available 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. Para 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 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 The neuromuscular electric stimulation (NMES is an important tool used in sports medicine to accelerate the recovery process. The objective of this study was to analyze the effects of NMES during immobilization of the gastrocnemius muscle, in lengthened (LP and shortened positions (SP. Sixty young female Wistar rats were distributed into six groups and followed for 7 days: control (C; electric stimulation (ES; immobilized in shortening (ISP; immobilized in lengthening (ILP; immobilized in shortening and electric stimulation (ISP + ES and immobilized in lengthening and electric stimulation (ILP + ES. For the immobilization, a tubular mesh and cotton rolls together with the plaster were wrapped around the rat's right posterior paw. NMES in a frequency of 50 Hz was used 10 minutes a day, totaling 20 contractions in each session. After 7 days the animals were sacrificed and their gastrocnemius muscles of the right paw were submitted to a mechanical test of traction in a universal test machine (EMIC®. From the load versus elongation curves the following mechanical properties were obtained: elongation in the yield limit (EPL, load in the yield limit (LPL and stiffness. The SP and LP immobilizations promoted significant reductions (p < 0.05 in the EPL and LPL properties, b

João Paulo Chieregato Matheus

2007-02-01

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

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Full Text Available Abstract Background The use of botulinum toxin A (BT-A for the treatment of lower limb spasticity is common in children with cerebral palsy (CP. Following the administration of BT-A, physical therapy plays a fundamental role in potentiating the functionality of the child. The balance deficit found in children with CP is mainly caused by muscle imbalance (spastic agonist and weak antagonist. Neuromuscular electrical stimulation (NMES is a promising therapeutic modality for muscle strengthening in this population. The aim of the present study is to describe a protocol for a study aimed at analyzing the effects of NMES on dorsiflexors combined with physical therapy on static and functional balance in children with CP submitted to BT- A. Methods/Design Protocol for a prospective, randomized, controlled trial with a blinded evaluator. Eligible participants will be children with cerebral palsy (Levels I, II and III of the Gross Motor Function Classification System between five and 12 years of age, with independent gait with or without a gait-assistance device. All participants will receive BT-A in the lower limbs (triceps surae. The children will then be randomly allocated for either treatment with motor physical therapy combined with NMES on the tibialis anterior or motor physical therapy alone. The participants will be evaluated on three occasions: 1 one week prior to the administration of BT-A; 2 one week after the administration of BT-A; and 3 four months after the administration of BT-A (end of intervention. Spasticity will be assessed by the Modified Ashworth Scale and Modified Tardieu Scale. Static balance will be assessed using the Medicapteurs Fusyo pressure platform and functional balance will be assessed using the Berg Balance Scale. Discussion The aim of this protocol study is to describe the methodology of a randomized, controlled, clinical trial comparing the effect of motor physical therapy combined with NMES on the tibialis anterior muscle or motor physical therapy alone on static and functional balance in children with CP submitted to BT-A in the lower limbs. This study describes the background, hypotheses, methodology of the procedures and measurement of the results. Trial registration RBR5qzs8h

Kazon Soráia

2012-05-01

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

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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

 
 
 
 
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[Neuromuscular monitoring].  

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The effect of muscle relaxants varies among people and the extent, the duration and recovery from the neuromuscular block varies. Clinical tests cannot determine the effect of muscle relaxants which is only possible with neuromuscular monitoring. The relaxometry procedure measures the muscular response to electrical stimulation of the corresponding motor nerve and the adductor pollicis muscle is mostly used; however, this muscle is not representative for other muscle groups, such as the muscles of the larynx and diaphragm. The muscles of the larynx and diaphragm are more resistant against nondepolarizing muscle relaxants than the adductor pollicis muscle. The train of four (TOF) is used at the beginning of surgery for monitoring of the optimal time for tracheal intubation; moreover, the TOF is used during surgery for monitoring of the muscle blockade and at the end of surgery for monitoring recovery. Monitoring of deep muscular blockades, however, is only possible with the posttetanic count (PTC) when there are no TOF counts. The PTC allows repetition and higher doses of muscle relaxants during abdominal surgery; therefore, conditions for surgery are optimal and cumulation of muscle relaxants is avoided. PMID:24150775

Mencke, T; Schmartz, D; Fuchs-Buder, T

2013-10-01

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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  

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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

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

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Full Text Available SciELO Brazil | Language: English Abstract in english BACKGROUND: Elastic resistance bands (ERB) combined with proprioceptive neuromuscular facilitation (PNF) are often used in resistance muscle training programs, which have potential effects on peripheral muscle strength. However, the effects of the combination of ERB and PNF on respiratory muscle s [...] trength warrant further investigation. OBJECTIVES: The assessment of the effects of PNF combined with ERB on respiratory muscle strength. METHOD: Twenty healthy, right-handed females were included. Subjects were randomized to either the resistance training program group (TG, n=10) or the control group (CG, n=10). Maximal expiratory pressure (MEP) and inspiratory pressure (MIP) were measured before and after four weeks of an upper extremity resistance training program. The training protocol consisted of upper extremity PNF combined with ERB, with resistance selected from 1 repetition maximum protocol. RESULTS: PNF combined with ERB showed significant increases in MIP and MEP (p

Guilherme P. T., Areas; Audrey, Borghi-Silva; Arianne N., Lobato; Alessandra A., Silva; Renato C., Freire Jr; Fernando Z. S., Areas.

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

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Full Text Available SciELO Brazil | Language: English Abstract in english BACKGROUND: Elastic resistance bands (ERB) combined with proprioceptive neuromuscular facilitation (PNF) are often used in resistance muscle training programs, which have potential effects on peripheral muscle strength. However, the effects of the combination of ERB and PNF on respiratory muscle s [...] trength warrant further investigation. OBJECTIVES: The assessment of the effects of PNF combined with ERB on respiratory muscle strength. METHOD: Twenty healthy, right-handed females were included. Subjects were randomized to either the resistance training program group (TG, n=10) or the control group (CG, n=10). Maximal expiratory pressure (MEP) and inspiratory pressure (MIP) were measured before and after four weeks of an upper extremity resistance training program. The training protocol consisted of upper extremity PNF combined with ERB, with resistance selected from 1 repetition maximum protocol. RESULTS: PNF combined with ERB showed significant increases in MIP and MEP (p

Guilherme P. T., Areas; Audrey, Borghi-Silva; Arianne N., Lobato; Alessandra A., Silva; Renato C., Freire Jr; Fernando Z. S., Areas.

2013-12-01

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Different mechanisms of Ca2+ regulation that influence synaptic transmission: comparison between crayfish and Drosophila neuromuscular junctions.  

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A brief historical background on synaptic transmission in relation to Ca(2+) dynamics and short-term facilitation is described. This study focuses on the mechanisms responsible for the regulation of intracellular calcium concentration ([Ca(2+)](i)) in high output terminals of larval Drosophila compared to a low-output terminal of the crayfish neuromuscular junction (NMJ). Three processes; plasmalemmal Na(+)/Ca(2+) exchanger [NCX], Ca(2+)-ATPase (PMCA), and sarcoplasmic/endoplasmic Ca(2+)-ATPase (SERCA) are important in regulating the [Ca(2+)](i) are examined. When the NCX is compromised by reduced [Na(+)](o), no consistent effect occurred; but a NCX blocker KB-R7943 decreased the excitatory postsynaptic potential (EPSP) amplitudes. Compromising the PMCA with pH 8.8 resulted in an increase in EPSP amplitude but treatment with a PMCA specific inhibitor carboxyeosin produced opposite results. Thapsigargin exposure to block the SERCA generally decreases EPSP amplitude. Compromising the activity of the above Ca(2+) regulating proteins had no substantial effects on short-term depression. The Kum(170TS) strain (with dysfunctional SERCA), showed a decrease in EPSP amplitudes including the first EPSP within the train. Synaptic transmission is altered by reducing the function of the above three [Ca(2+)](i) regulators; but they are not consistent among different species as expected. Results in crayfish NMJ were more consistent with expected results as compared to the Drosophila NMJ. It is predicated that different mechanisms are used for regulating the [Ca(2+)](i) in high and low output synaptic terminals. PMID:19650116

Desai-Shah, Mohati; Cooper, Robin L

2009-12-01

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The drop-jump video screening test: retention of improvement in neuromuscular control in female volleyball players.  

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A valgus lower limb alignment is commonly documented during noncontact anterior cruciate ligament injuries. We previously developed a videographic drop-jump test to measure overall lower limb alignment in the coronal plane as a screening tool to detect such an abnormal (valgus) position on landing. A neuromuscular retraining program developed for female athletes was shown to be effective in improving lower limb alignment on this test immediately after completion of training. What remained unknown was whether these improvements would be retained for longer periods of time. Therefore, this study was undertaken to determine if these improvements in overall lower limb alignment would be retained up to 1 year after the training. Sixteen competitive, experienced female high-school volleyball players underwent the video drop-jump test and then completed the neuromuscular retraining program. The program consisted of a dynamic warm-up, jump training, speed and agility drills, strength training, and static stretching and was performed 3 times a week for 6 weeks. The athletes repeated the drop-jump test immediately upon completion of training and then 3- and 12-months later. Significant improvements were found in the mean normalized knee separation distance between the pre and posttrained values for all test sessions (p < 0.01). Immediately after training, 11 athletes (69%) displayed significant improvements in the mean normalized knee separation distance that were retained 12 months later. Five athletes failed to improve. The video drop-jump test, although not a risk indicator for a knee ligament injury, provides a cost-effective general assessment of lower limb position and depicts athletes who have poor control on landing and acceleration into a vertical jump. PMID:20940643

Barber-Westin, Sue D; Smith, Stephanie T; Campbell, Thomas; Noyes, Frank R

2010-11-01

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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.

48

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

49

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

Science.gov (United States)

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. PMID:23787058

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

2013-10-01

50

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

51

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

52

Control Rod Drive Mechanism.  

Science.gov (United States)

The control rod driving mechanism is used in a nuclear reactor. A pneumatic system is used as a basic drive while an integral and co-functioning electromechanical system provides precise positional control. The reactor coolant fluid itself is used to driv...

D. Nicoll

1965-01-01

53

Neuromuscular control model of the arm including feedback and feedforward components.  

Science.gov (United States)

A neuromusculoskeletal model of the human arm was developed which contains both feedforward and feedback control, and thereby accounts for motor control of fast movements as well as interaction with external forces. The feedforward control component forms an approximate representation of the inverse dynamics of the arm and its interaction with the environment. The feedback control component compensates for errors in the representation of the inverse dynamics and for unexpected forces acting on the arm. Moreover, the control system provides a solution for the redundancy of the muscles. The system performance is adapted in a learning procedure according to a specified goal function. It is shown in the paper that good control of the nonlinear musculoskeletal model and neural control signals which are similar to electromyographic (EMG) data, are attained. The response of the arm to external forces is analysed and compared with experimental data on arm impedance. PMID:9844560

Stroeve, S

1998-11-01

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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

55

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

56

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

Science.gov (United States)

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

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

2011-03-01

57

Coordination and neuromuscular control of rhythmic behaviors in the blue crab, Callinectes sapidus.  

Science.gov (United States)

The stereotypical courtship display (CD) behavior of the male blue crab, Callinectes sapidus, includes an unusual component: the rhythmic waving of the swimming appendages above the carapace. This behavior occurs in a unique context but it resembles two other rhythmic behaviors performed using the swimming legs: sideways swimming and backward swimming. As a first step to understanding the mechanisms that allow the expression of apparently different rhythmic motor patterns, we have examined these behaviors using slow motion video analysis and electromyography of the basal muscles of the swimming legs in freely behaving crabs. The results show that these behaviors are distinguished by four parameters: the frequency of leg waving, the phase relationship between the legs, the presence of a stationary pause in basal muscle activity combined with rotation of the distal leg during CD, and an extended range of motion of these legs during CD and backward swimming, relative to sideways swimming. EMG analysis revealed that during sideways swimming, the sequence of muscular activity between the two legs was different. In contrast, during CD and backward swimming the sequence of activity for these legs is identical. PMID:7643320

Wood, D E; Derby, C D

1995-09-01

58

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.)

59

Age-related neuromuscular function and dynamic balance control during slow and fast balance perturbations.  

Science.gov (United States)

This study investigated age-related differences in dynamic balance control and its connection to reflexes and explosive isometric plantar flexor torque in 19 males (9 Young aged 20-33 yr, 10 Elderly aged 61-72 yr). Dynamic balance was measured during Slow (15 cm/s) and Fast (25 cm/s) anterior and posterior perturbations. H/M-ratio was measured at 20% of maximal M-wave (H/M20%) 10, 30, and 90 ms after perturbations. Stretch reflexes were measured from tibialis anterior and soleus during anterior and posterior perturbations, respectively. In Slow, Elderly exhibited larger peak center-of-pressure (COP) displacement (15%; P < 0.05) during anterior perturbations. In Fast, Young showed a trend for faster recovery (37%; P = 0.086) after anterior perturbations. M-wave latency was similar between groups (6.2 ± 0.7 vs. 6.9 ± 1.2 ms), whereas Elderly showed a longer H-reflex latency (33.7 ± 2.3 vs. 36.4 ± 1.7 ms; P < 0.01). H/M20% was higher in Young 30 ms after Fast anterior (50%; P < 0.05) and posterior (51%; P < 0.05) perturbations. Plantar flexor rapid torque was also higher in Young (26%; P < 0.05). After combining both groups' data, H/M20% correlated negatively with Slow peak COP displacement (r = -0.510, P < 0.05) and positively with Fast recovery time (r = 0.580, P < 0.05) for anterior perturbations. Age-related differences in balance control seem to be more evident in anterior than posterior perturbations, and rapid sensory feedback is generally important for balance perturbation recovery. PMID:24047908

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

2013-12-01

60

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish Las alteraciones neuromusculares que tienen lugar en el paciente crítico han sido atribuidas a factores como la situación séptica, la liberación de mediadores inflamatorioso el empleo de fármacos que afectan desfavorablemente a la función neuro-muscular. El papel de factores metabólicos y nutriciona [...] les en el desarrollo de esta patología ha recibido poca atención. En la actualidad, el empleo de protocolos de control intensivo de la glucemia podría tener gran interés en la prevención de las alteraciones neuro-musculares de los pacientes críticos. Los mecanismos exactos de la implicación de la hiperglucemia en esta patología son, todavía, desconocidos, aunque la evidencia de los datos procedentes de la investigación es importante. La miopatía caquectizante (atrofia muscular) tiene lugar de manera habitual como consecuencia de los cambios obligados por la respuesta metabólica al estrés. El efecto del aporte de nutrientes sobre la ganancia de masa muscular es muy limitado, por lo que deben estudiarse otras acciones dirigidas a recuperar, de manera más rápida, la masa muscular perdida. Deben evitarse pautas agresivas de renutrición con objeto de prevenir el síndrome de realimentación y el consiguiente mayor deterioro de la función muscular. El aporte de substratos específicos, como la glutamina, podría tener un efecto beneficioso en la recuperación de las alteraciones neuro-musculares del paciente crítico. No obstante, no existen aún datos para justificar su empleo si el único objetivo es la recuperación de la función neuro-muscular. Abstract in english Neuromuscular impairments occurring in the critically ill patient have been attributed to factors such as sepsis, release of inflammatory mediators, or the use of drugs unfavorably affecting neuromuscular function. The role of metabolic and nutritional factors in the development of this condition ha [...] s received little attention. Currently, the use of protocols of intensive glycemia monitoring might be of great interest in preventing neuromuscular impairments in critically ill patients. The precise mechanisms of hyperglycemia involvement in this condition are still unknown, although evidence from research data is important. Cachectic myopathy (muscle atrophy) usually is the result of the obliged changes of metabolic response to stress. The effect of nutrients intake on muscle mass gaining is very limited, so that other actions aimed at more rapidly recovering lost muscle mass should be studied. Aggressive renutrition schedules should be avoided in order to prevent re-nutrition syndrome and further deterioration of muscle function. Intake of specific substrates, such as glutamine,might have a beneficial effect on recovering neuromuscular impairments in the critically ill patient. However, there are still no data to justify its use if the only purpose is to recover neuromuscular function.

J. C., Montejo González.

2006-05-01

 
 
 
 
61

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish Las alteraciones neuromusculares que tienen lugar en el paciente crítico han sido atribuidas a factores como la situación séptica, la liberación de mediadores inflamatorioso el empleo de fármacos que afectan desfavorablemente a la función neuro-muscular. El papel de factores metabólicos y nutriciona [...] les en el desarrollo de esta patología ha recibido poca atención. En la actualidad, el empleo de protocolos de control intensivo de la glucemia podría tener gran interés en la prevención de las alteraciones neuro-musculares de los pacientes críticos. Los mecanismos exactos de la implicación de la hiperglucemia en esta patología son, todavía, desconocidos, aunque la evidencia de los datos procedentes de la investigación es importante. La miopatía caquectizante (atrofia muscular) tiene lugar de manera habitual como consecuencia de los cambios obligados por la respuesta metabólica al estrés. El efecto del aporte de nutrientes sobre la ganancia de masa muscular es muy limitado, por lo que deben estudiarse otras acciones dirigidas a recuperar, de manera más rápida, la masa muscular perdida. Deben evitarse pautas agresivas de renutrición con objeto de prevenir el síndrome de realimentación y el consiguiente mayor deterioro de la función muscular. El aporte de substratos específicos, como la glutamina, podría tener un efecto beneficioso en la recuperación de las alteraciones neuro-musculares del paciente crítico. No obstante, no existen aún datos para justificar su empleo si el único objetivo es la recuperación de la función neuro-muscular. Abstract in english Neuromuscular impairments occurring in the critically ill patient have been attributed to factors such as sepsis, release of inflammatory mediators, or the use of drugs unfavorably affecting neuromuscular function. The role of metabolic and nutritional factors in the development of this condition ha [...] s received little attention. Currently, the use of protocols of intensive glycemia monitoring might be of great interest in preventing neuromuscular impairments in critically ill patients. The precise mechanisms of hyperglycemia involvement in this condition are still unknown, although evidence from research data is important. Cachectic myopathy (muscle atrophy) usually is the result of the obliged changes of metabolic response to stress. The effect of nutrients intake on muscle mass gaining is very limited, so that other actions aimed at more rapidly recovering lost muscle mass should be studied. Aggressive renutrition schedules should be avoided in order to prevent re-nutrition syndrome and further deterioration of muscle function. Intake of specific substrates, such as glutamine,might have a beneficial effect on recovering neuromuscular impairments in the critically ill patient. However, there are still no data to justify its use if the only purpose is to recover neuromuscular function.

J. C., Montejo González.

62

Neuromuscular fatigue in racquet sports.  

Science.gov (United States)

This article describes the physiologic and neural mechanisms that cause neuromuscular fatigue in racquet sports: table tennis, tennis, squash, and badminton. In these intermittent and dual activities, performance may be limited as a match progresses because of a reduced central activation, linked to changes in neurotransmitter concentration or in response to afferent sensory feedback. Alternatively, modulation of spinal loop properties may occur because of changes in metabolic or mechanical properties within the muscle. Finally, increased fatigue manifested by mistimed strokes, lower speed, and altered on-court movements may be caused by ionic disturbances and impairments in excitation-contraction coupling properties. These alterations in neuromuscular function contribute to decrease in racquet sports performance observed under fatigue. PMID:19084769

Girard, Olivier; Millet, Grégoire P

2009-02-01

63

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

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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

65

Biomarkers in rare neuromuscular diseases.  

Science.gov (United States)

Neuromuscular diseases (NMDs) comprise a range of rare disorders that include both hereditary peripheral neuropathies and myopathies. The heterogeneity and rarity of neuromuscular disorders are challenges for researchers seeking to develop effective diagnosis and treatment strategies. In particular, clinical trials of new therapies are made more difficult due to lack of reliable and monitorable clinical outcome measures. Biomarkers could be a way to speed up research in this field, shedding light on the pathophysiological mechanisms behind such diseases and providing invaluable tools for monitoring their progression, prognosis and response to drug treatment. Furthermore, biomarkers could represent a surrogate endpoint for clinical trials, enabling better stratification of patient cohorts through more accurate diagnosis and prognosis prediction. This review summarizes the types, applications, characteristics and best strategies for biomarker discovery to date. PMID:24389168

Scotton, Chiara; Passarelli, Chiara; Neri, Marcella; Ferlini, Alessandra

2014-07-01

66

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

67

Presynaptic K(+) channels, vesicular Ca(2+)/H (+) antiport--synaptotagmin, and acetylcholinesterase, three mechanisms cutting short the cholinergic signal at neuromuscular and nerve-electroplaque junctions.  

Science.gov (United States)

In neuromuscular and nerve-electroplaque junctions, nerve impulses can be transmitted at high frequencies. This implies that transmission of individual impulses must be very brief. We describe three mechanisms which curtail the time course of individual impulses at these synapses: (1) opening of presynaptic K(+) channels (delayed rectifier) efficiently curtails the presynaptic action potential. Inhibition of K(+) channel by aminopyridines transforms the normally brief postsynaptic potential (2-3 ms) to a long-lasting "giant" potential (exceeding half a second); (2) a low-affinity Ca(2+)/H(+) antiport ensures rapid Ca(2+) sequestration into synaptic vesicles, curtailing the calcium signal and thereby the duration of transmitter release. Indeed vesicular Ca(2+)/H(+) antiport inhibition by bafilomycin or Sr(2+) prolongs the duration of the postsynaptic potential. We recently showed that synaptotagmin-1 is required for this antiport activity; thus the vesicular Ca(2+)/H(+) antiport might be synaptotagmin itself, or regulated by it; and (3) it is recalled that, in these junctions, acetylcholinesterase is highly concentrated in the synaptic cleft and that anticholinesterases lengthen the endplate time course. Therefore, at three different steps of synaptic transmission, an efficient mechanism curtails the local synaptic signal. When one of these three mechanisms is inhibited, the duration of individual impulses is prolonged, but the synapse loses its faculty to fire at high frequencies. PMID:24390960

Dunant, Yves; Cordeiro, J Miguel

2014-07-01

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

Directory of Open Access Journals (Sweden)

Full Text Available Las alteraciones neuromusculares que tienen lugar en el paciente crítico han sido atribuidas a factores como la situación séptica, la liberación de mediadores inflamatorioso el empleo de fármacos que afectan desfavorablemente a la función neuro-muscular. El papel de factores metabólicos y nutricionales en el desarrollo de esta patología ha recibido poca atención. En la actualidad, el empleo de protocolos de control intensivo de la glucemia podría tener gran interés en la prevención de las alteraciones neuro-musculares de los pacientes críticos. Los mecanismos exactos de la implicación de la hiperglucemia en esta patología son, todavía, desconocidos, aunque la evidencia de los datos procedentes de la investigación es importante. La miopatía caquectizante (atrofia muscular tiene lugar de manera habitual como consecuencia de los cambios obligados por la respuesta metabólica al estrés. El efecto del aporte de nutrientes sobre la ganancia de masa muscular es muy limitado, por lo que deben estudiarse otras acciones dirigidas a recuperar, de manera más rápida, la masa muscular perdida. Deben evitarse pautas agresivas de renutrición con objeto de prevenir el síndrome de realimentación y el consiguiente mayor deterioro de la función muscular. El aporte de substratos específicos, como la glutamina, podría tener un efecto beneficioso en la recuperación de las alteraciones neuro-musculares del paciente crítico. No obstante, no existen aún datos para justificar su empleo si el único objetivo es la recuperación de la función neuro-muscular.Neuromuscular impairments occurring in the critically ill patient have been attributed to factors such as sepsis, release of inflammatory mediators, or the use of drugs unfavorably affecting neuromuscular function. The role of metabolic and nutritional factors in the development of this condition has received little attention. Currently, the use of protocols of intensive glycemia monitoring might be of great interest in preventing neuromuscular impairments in critically ill patients. The precise mechanisms of hyperglycemia involvement in this condition are still unknown, although evidence from research data is important. Cachectic myopathy (muscle atrophy usually is the result of the obliged changes of metabolic response to stress. The effect of nutrients intake on muscle mass gaining is very limited, so that other actions aimed at more rapidly recovering lost muscle mass should be studied. Aggressive renutrition schedules should be avoided in order to prevent re-nutrition syndrome and further deterioration of muscle function. Intake of specific substrates, such as glutamine,might have a beneficial effect on recovering neuromuscular impairments in the critically ill patient. However, there are still no data to justify its use if the only purpose is to recover neuromuscular function.

J. C. Montejo González

2006-05-01

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Genetics and Neuromuscular Diseases  

Science.gov (United States)

... included in MDA’s program: Muscular Dystrophies Myotonic dystrophy (Steinert disease) Duchenne muscular dystrophy Becker muscular dystrophy Limb- ... 4) Spinal-bulbar muscular atrophy ( Kennedy disease) Inflammatory Myopathies Polymyositis Dermatomyositis Inclusion-body myositis Diseases of 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

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Neuromuscular versus quadriceps strengthening exercise in people with medial knee osteoarthritis and varus malalignment : A randomised 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 medio-lateral distribution of knee load), pain and physical function in people with medial knee joint osteoarthritis (OA) and varus malalignment. Methods: 100 people 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 (3D gait analysis), pain (visual analogue scale), and self-reported physical function (Western Ontario and McMaster Universities Osteoarthritis Index). Results: 82 participants (38/50 (76%) NEXA, 44/50 (88%) QS) completed the trial. There was no significant between-group difference in the change in the peak knee adduction moment (mean difference (95% CI) 0.134 (-0.069 to 0.337) Nm/(BW.HT)%), pain (2.4 (-6.0 to 10.8) mm) or physical function (-0.8 (-4.0 to 2.4) units). Neither group showed a change in knee moments following exercise, whereas both groups showed similar significant reductions in pain and physical dysfunction. Conclusions: Although comparable improvements in clinical outcomes were found for both neuromuscular and quadriceps strengthening exercise in people 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. Australia and New Zealand Clinical Trials Registry (#ACTRN12610000660088) © 2013 American College of Rheumatology.

Bennell, Kim L; Kyriakides, Mary

2014-01-01

72

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

73

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.)

74

Oxidative stress disrupts purinergic neuromuscular transmission in the inflamed colon.  

Science.gov (United States)

Colitis, induced by trinitrobenzene sulfonic acid (TNBS) in guinea pig, leads to decreased purinergic neuromuscular transmission resulting in a reduction in inhibitory junction potentials (IJPs) in colonic circular muscle. We explored possible mechanisms responsible for this inflammation-induced neurotransmitter plasticity. Previous studies have suggested that the deficit in inflamed tissue involves decreased ATP release. We therefore hypothesized that decreased purinergic transmission results from inflammation-induced free radical damage to mitochondria, leading to decreased purine synthesis and release. Stimulus-induced release of purines was measured using high-performance liquid chromatography, and quantities of all purines measured were significantly reduced in the inflamed colons as compared to controls. To test whether decreased mitochondrial function affects the IJP, colonic muscularis preparations were treated with the mitochondrial ATP synthase inhibitors oligomycin or dicyclohexylcarbodiimide, which resulted in a significant reduction of IJP amplitude. Induction of oxidative stress in vitro, by addition of H2O2 to the preparation, also significantly reduced IJP amplitude. Purinergic neuromuscular transmission was significantly restored in TNBS-inflamed guinea pigs, and in dextran sodium sulfate-inflamed mice, treated with a free radical scavenger. Furthermore, propulsive motility in the distal colons of guinea pigs with TNBS colitis was improved by in vivo treatment with the free radical scavenger. We conclude that oxidative stress contributes to the reduction in purinergic neuromuscular transmission measured in animal models of colitis, and that these changes can be prevented by treatment with a free radical scavenger, resulting in improved motility. PMID:23732648

Roberts, Jane A; Durnin, Leonie; Sharkey, Keith A; Mutafova-Yambolieva, Violeta N; Mawe, Gary M

2013-08-01

75

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.)

76

Hereditary neuromuscular diseases  

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-12-01

77

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.)

78

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

Science.gov (United States)

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. PMID:21658224

2011-01-01

79

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

80

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

 
 
 
 
81

Neuromuscular control of trout swimming in a vortex street: implications for energy economy during the Karman gait.  

Science.gov (United States)

Approximating the complexity of natural locomotor conditions provides insight into the diversity of mechanisms that enable animals to successfully navigate through their environment. When exposed to vortices shed from a cylinder, fishes hold station by adopting a mode of locomotion called the Kármán gait, whereby the body of the fish displays large, lateral oscillations and the tail-beat frequency matches the vortex shedding frequency of the cylinder. Although field studies indicate that fishes often prefer turbulent flows over uniform currents, the effect of hydrodynamic perturbations on the mechanics, control and energetics of locomotion is still poorly understood. In this study, electromyography is used to measure red and white axial muscle activity for rainbow trout (Oncorhynchus mykiss) holding station in a vortex street. When trout Kármán gait, they show a significantly reduced but still rhythmic pattern of muscle activity compared with that seen when they swim steadily in uniform flow. Specifically, trout selectively activated only their anterior red axial muscles and abandoned the antero-posterior wave of red muscle activity that drives undulatory locomotion in uniform flow. This supports a previously proposed hypothesis that trout are not just swimming in the reduced flow behind a cylinder (drafting). Anterior axial muscle activity was correlated to head amplitude during steady swimming but not during the Kármán gait, indicating that while activation of muscles during the Kármán gait may aid in stability and control, vortices determined overall head motion. Furthermore, anterior red axial muscle activity, the only region of muscle activity shared between both the Kármán gait and steady swimming, had a lower intensity and longer duration during the Kármán gait. At times when paired fins were active during the Kármán gait, there was no axial muscle activity measured, lending support to a passive mechanism of thrust generation in oscillating flows. Comparisons with dead trout towed behind a cylinder confirm this intriguing observation that live trout may temporarily adopt the Kármán gait with no axial muscle activity, revealing paradoxically that at times fish can passively move against turbulent flow. To Kármán gait for prolonged periods, however, trout must adapt to the demands of turbulence by eliciting a shift in neural control strategy. By decoupling motor output both down and across the body, the pattern of rhythmic Kármán gait muscle activity may reflect the entrainment of a central pattern generator to environmental vortices. PMID:15339945

Liao, James C

2004-09-01

82

Schwann cells sense and control acetylcholine spillover at the neuromuscular junction by ?7 nicotinic receptors and butyrylcholinesterase.  

Science.gov (United States)

Terminal Schwann cells (TSCs) are key components of the mammalian neuromuscular junction (NMJ). How the TSCs sense the synaptic activity in physiological conditions remains unclear. We have taken advantage of the distinct localization of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) at the NMJ to bring out the function of different ACh receptors (AChRs). AChE is clustered by the collagen Q in the synaptic cleft and prevents the repetitive activation of muscle nicotinic AChRs. We found that BChE is anchored at the TSC by a proline-rich membrane anchor, the small transmembrane protein anchor of brain AChE. When BChE was specifically inhibited, ACh release was significant depressed through the activation of ?7 nAChRs localized on the TSC and activated by the spillover of ACh. When both AChE and BChE were inhibited, the spillover increased and induced a dramatic reduction of ACh release that compromised the muscle twitch triggered by the nerve stimulation. ?7 nAChRs at the TSC may act as a sensor for spillover of ACh adjusted by BChE and may represent an extrasynaptic sensor for homeostasis at the NMJ. In myasthenic rats, selective inhibition of AChE is more effective in rescuing muscle function than the simultaneous inhibition of AChE and BChE because the concomitant inhibition of BChE counteracts the positive action of AChE inhibition. These results show that inhibition of BChE should be avoided during the treatment of myasthenia and the pharmacological reversal of residual curarization after anesthesia. PMID:25186736

Petrov, Konstantin A; Girard, Emmanuelle; Nikitashina, Alexandra D; Colasante, Cesare; Bernard, Véronique; Nurullin, Leniz; Leroy, Jacqueline; Samigullin, Dmitry; Colak, Omer; Nikolsky, Evgenii; Plaud, Benoit; Krejci, Eric

2014-09-01

83

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

84

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.

85

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

86

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.

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

2014-01-01

87

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background. Tai Chi is a traditional Chinese medicine exercise used for improving neuromuscular function. This study aimed to investigate the effects of Tai Chi versus proprioception exercise program on neuromuscular function of the ankle in elderly people. Methods. Sixty elderly subjects were randomly allocated into three groups of 20 subjects per group. For 16 consecutive weeks, subjects participated in Tai Chi, proprioception exercise, or no structured exercise. Primary outcome measures in...

Jing Liu,; Xue-Qiang Wang; Jie-Jiao Zheng; Yu-Jian Pan; Ying-Hui Hua; Shang-Min Zhao; Li-Yan Shen; Shuai Fan; Jiu-Gen Zhong

2012-01-01

88

Control elements in mechanism simulation  

Directory of Open Access Journals (Sweden)

Full Text Available The work reported in this paper is a step towards a system for multidisciplinary simulation of structure, mechanism and control elements. The control part of the system is implemented as a subroutine called from the mechanism/FEM package. While Newmark's/beta-method is used to integrate the second order mechanism/FEM part, the Lobatto IIIC algorithm is applied to the first order control elements. Preliminary experiments show that this is a workable solution. The package will be further developed to include more elements, improve the performance and add enhanced graphics. The control part can easily be used as a stand alone simulator for the integration of first order differential/algebraic equations.

Torleif Iversen

1989-07-01

89

Mechanics, modulation and modelling: how muscles actuate and control movement.  

Science.gov (United States)

Animal movement is often complex, unsteady and variable. The critical role of muscles in animal movement has captivated scientists for over 300 years. Despite this, emerging techniques and ideas are still shaping and advancing the field. For example, sonomicrometry and ultrasound techniques have enhanced our ability to quantify muscle length changes under in vivo conditions. Robotics and musculoskeletal models have benefited from improved computational tools and have enhanced our ability to understand muscle function in relation to movement by allowing one to simulate muscle-tendon dynamics under realistic conditions. The past decade, in particular, has seen a rapid advancement in technology and shifts in paradigms related to muscle function. In addition, there has been an increased focus on muscle function in relation to the complex locomotor behaviours, rather than relatively simple (and steady) behaviours. Thus, this Theme Issue will explore integrative aspects of muscle function in relation to diverse locomotor behaviours such as swimming, jumping, hopping, running, flying, moving over obstacles and transitioning between environments. Studies of walking and running have particular relevance to clinical aspects of human movement and sport. This Theme Issue includes contributions from scientists working on diverse taxa, ranging from humans to insects. In addition to contributions addressing locomotion in various taxa, several manuscripts will focus on recent advances in neuromuscular control and modulation during complex behaviours. Finally, some of the contributions address recent advances in biomechanical modelling and powered prostheses. We hope that our comprehensive and integrative Theme Issue will form the foundation for future work in the fields of neuromuscular mechanics and locomotion. PMID:21502117

Higham, Timothy E; Biewener, Andrew A; Delp, Scott L

2011-05-27

90

Mechanical control of Renilla luciferase.  

Science.gov (United States)

We report experiments where the activity of the enzyme luciferase from Renilla reniformis is controlled through a DNA spring attached to the enzyme. In the wake of previous work on kinases, these results establish that mechanical stress applied through the DNA springs is indeed a general method for the artificial control of enzymes, and for the quantitative study of mechano-chemical coupling in these molecules. We also show proof of concept of the luciferase construct as a sensitive molecular probe, detecting a specific DNA target sequence in an easy, one-step, homogeneous assay, as well as SNP detection without melting curve analysis. PMID:23863076

Tseng, Chiao-Yu; Zocchi, Giovanni

2013-08-14

91

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

92

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.

93

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

94

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

2014-01-01

95

A suicide with neuromuscular blocker.  

Science.gov (United States)

We experienced an autopsy case in which a 29-year-old woman committed suicide by parenteral application of a neuromuscular blocker combined with thiobarbital. These medicines were easily accessible to the victim who was an anesthesiologist in a hospital. Paralyzing the respiratory muscles the usual dose of neuromuscular blockers can cause death unless a breathing apparatus is used. Unusual medicines given in small doses are difficult to detect in the autopsy materials. In our case in the course of forensic investigation we successfully identified the traces of a neuromuscular blocker by mass spectrometry. PMID:2845685

Varga, M; Somogyi, G

1988-01-01

96

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

97

What Is a Neuromuscular Disease?  

Science.gov (United States)

... are under age 18. All neuromuscular diseases are progressive in nature, and all result in muscle weakness ... Association (MDA) is a qualified 501(c)(3) tax-exempt organization. ©2014, Muscular Dystrophy Association Inc. All ...

98

Autoimmune mediated neuromuscular junction defects.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

PURPOSE OF REVIEW: This review summarizes the recent advances on pathogenesis of antibody-mediated disorders of the neuromuscular junction, and results of studies on clinical assessment and treatments. RECENT FINDINGS: The incidence of myasthenia gravis, particularly in patients older than 50 years, is rising, and this is not solely due to improved disease recognition. It is uncertain how muscle specific tyrosine kinase (MuSK) antibody positive myasthenia gravis results in neuromuscular trans...

Farrugia, Me; Vincent, A.

2010-01-01

99

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

100

Effect of experimental cholestasis on neuromuscular blocking drugs in cats.  

Science.gov (United States)

Pancuronium, Org 6368 and gallamine were compared in control cats and in cats with experimental cholestasis. A decrease in the plasma clearance and a prolongation of neuromuscular blockade with Org 6368 and pancuronium were found in the latter; no significant difference was detected in the biotransformation pattern of Org 6368 and pancuronium compared with controls. Inhibition of hepatic uptake of Org 6368 and pancuronium in extrahepatic cholestasis might explain the significant alterations in the pharmacokinetics of the two steroid neuromuscular blocking drugs. The pharmacokinetics of gallamine were normal during cholestasis. The results suggest that, under pathological conditions involving increased plasma concentrations of bile salts, neuromuscular blocking agents that are cleared from the plasma by the liver may have an impaired hepatic uptake and consequently a prolonged duration of action. PMID:7426252

Westra, P; Houwertjes, M C; de Lange, A R; Scaf, A H; Hindriks, F R; Agoston, S

1980-08-01

 
 
 
 
101

Paradoxical antagonism of neuromuscular block by vecuronium metabolites.  

Directory of Open Access Journals (Sweden)

Full Text Available Vecuronium is hydrolyzed in the body to 3-deacetyl (ORG 7268, 17-deacetyl (ORG NC58, and 3, 17-bis-deacetyl (ORG 7402 derivatives. Interactions of vecuronium and these metabolites were studied in phrenic nerve-hemidiaphragm preparations of rats. As already reported, ORG 7268 had a potent neuromuscular blocking action, and ORG NC58 and ORG 7402 had a weak neuromuscular blocking action. As expected, ORG 7268 increased the degree of neuromuscular block by vecuronium. However, a low concentration (10 microM of ORG NC58 and ORG 7402 reversed the block by vecuronium. At a high concentration (50 microM, ORG NC58 and ORG 7402 increased the degree of block by vecuronium. Although we do not have enough data to explain these paradoxical reversal of neuromuscular block at this moment, we postulate that these results reflect the interaction between "slow" and "fast" competitive antagonists. Regardless of the mechanism, it should be emphasized that the concentrations of ORG NC58 and ORG 7402 which are necessary to reverse the block are much lower than those which facilitate the block. It is conceivable that this paradoxical reversal of the block occurs in experimental and clinical situations. Therefore, in determining the neuromuscular blocking action of a compound, the "antagonistic" effect of its metabolites should also be considered.

Ohta,Yoshio

1985-12-01

102

Age-related neuromuscular function during drop jumps.  

Science.gov (United States)

Muscle- and movement-specific fascicle-tendon interaction affects the performance of the neuromuscular system. This interaction is unknown among elderly and consequently contributes to the lack of understanding the age-related problems on neuromuscular control. The present experiment studied the age specificity of fascicle-tendon interaction of the gastrocnemius medialis (GM) muscle in drop jump (DJ) exercises. Twelve young and thirteen elderly subjects performed maximal squat jumps and DJs with maximal rebound effort on a sledge apparatus. Ankle and knee joint angles, reaction force, and electromyography (EMG) from the soleus (Sol), GM, and tibialis anterior (TA) muscles were measured together with the GM fascicle length by ultrasonography. The results showed that the measured ankle joint stiffness (AJS) during the braking phase correlated positively with the rebound speed in both age groups and that both parameters were significantly lower in the elderly than in young subjects. In both groups, the AJS correlated positively with averaged EMG (aEMG) in Sol during the braking phase and was further associated with GM activation (r = 0.55, P < 0.01) and TA coactivation (TA/GM r = -0.4 P < 0.05) in the elderly subjects. In addition, compared with the young subjects, the elderly subjects showed significantly lower GM aEMG in the braking phase and higher aEMG in the push-off phase, indicating less utilization of tendinous tissue (TT) elasticity. These different activation patterns are in line with the mechanical behavior of GM showing significantly less fascicle shortening and relative TT stretching in the braking phase in the elderly than in the young subjects. These results suggest that age-specific muscle activation patterns as well as mechanical behaviors exist during DJs. PMID:17690197

Hoffrén, M; Ishikawa, M; Komi, P V

2007-10-01

103

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

104

Protein defects in neuromuscular diseases  

Directory of Open Access Journals (Sweden)

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

Vainzof M.

2003-01-01

105

Protein defects in neuromuscular diseases  

Scientific Electronic Library Online (English)

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

M., Vainzof; M., Zatz.

106

Neuromuscular Manifestations of West Nile Virus Infection  

Directory of Open Access Journals (Sweden)

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

A. ArturoLeis

2012-03-01

107

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

108

LRP4 Is Critical for Neuromuscular Junction Maintenance.  

Science.gov (United States)

The neuromuscular junction (NMJ) is a synapse between motor neurons and skeletal muscle fibers, and is critical for control of muscle contraction. Its formation requires neuronal agrin that acts by binding to LRP4 to stimulate MuSK. Mutations have been identified in agrin, MuSK, and LRP4 in patients with congenital myasthenic syndrome, and patients with myasthenia gravis develop antibodies against agrin, LRP4, and MuSK. However, it remains unclear whether the agrin signaling pathway is critical for NMJ maintenance because null mutation of any of the three genes is perinatal lethal. In this study, we generated imKO mice, a mutant strain whose LRP4 gene can be deleted in muscles by doxycycline (Dox) treatment. Ablation of the LRP4 gene in adult muscle enabled studies of its role in NMJ maintenance. We demonstrate that Dox treatment of P30 mice reduced muscle strength and compound muscle action potentials. AChR clusters became fragmented with diminished junctional folds and synaptic vesicles. The amplitude and frequency of miniature endplate potentials were reduced, indicating impaired neuromuscular transmission and providing cellular mechanisms of adult LRP4 deficiency. We showed that LRP4 ablation led to the loss of synaptic agrin and the 90 kDa fragments, which occurred ahead of other prejunctional and postjunctional components, suggesting that LRP4 may regulate the stability of synaptic agrin. These observations demonstrate that LRP4 is essential for maintaining the structural and functional integrity of the NMJ and that loss of muscle LRP4 in adulthood alone is sufficient to cause myasthenic symptoms. PMID:25319686

Barik, Arnab; Lu, Yisheng; Sathyamurthy, Anupama; Bowman, Andrew; Shen, Chengyong; Li, Lei; Xiong, Wen-Cheng; Mei, Lin

2014-10-15

109

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

110

Pharmacodynamic interaction between pantoprazole and vecuronium at neuromuscular junction.  

Science.gov (United States)

1?The effect of pantoprazole on vecuronium-induced neuromuscular blockade in in vivo has not been clearly defined. In this study, we demonstrate that chronic administration, but not acute administration, of pantoprazole alters the pattern of vecuronium-induced neuromuscular blockade. 2?This study was designed to evaluate the effect of acute and chronic administration of pantoprazole on vecuronium-induced neuromuscular blockade using the rat in vivo sciatic nerve-stimulated gastrocnemius preparation. 3?Vecuronium was administered as a slow intravenous infusion (29.41 ?g kg(-1) min(-1)) until the gastrocnemius twitch response to sciatic nerve stimulation was completely abolished. The effect of acute (single dose, i.v.) and chronic administration (per oral for 21 days) of pantoprazole (3.64 mg kg(-1)) on vecuronium-induced blockade was assessed by comparing ED50 values, time required for 50% block, ED95 values, block duration and percentage of recovery with respect to control. 4?Acute administration of pantoprazole had no significant effect on any parameter of vecuronium-induced neuromuscular blockade. Chronic administration of pantoprazole significantly reduced vecuronium ED50 value, time for 50% block, ED95 value and percentage recovery from blockade compared with the control group (P<0.05). Reduction in the duration of vecuronium-induced blockade was not significantly affected by chronic treatment with pantoprazole compared with control. 5?On chronic administration, pantoprazole may produce earlier block, quick relaxation and reduces the recovery of vecuronium without affecting its duration of action. PMID:21342416

Vadgama, V K; Patel, Y A; Patel, T K; Tripathi, C B

2011-01-01

111

Dual acting slit control mechanism  

Science.gov (United States)

A dual acting control system for mass spectrometers is described, which permits adjustment of the collimating slit width and centering of the collimating slit while using only one vacuum penetration. Coaxial shafts, each with independent vacuum bellows are used to independently move the entire collimating assembly or to adjust the slit dimension through a parallelogram linkage.

Struthoff, G. L. (inventor)

1980-01-01

112

Neuromuscular dressing effects: a literature review  

Directory of Open Access Journals (Sweden)

Full Text Available The kinesio taping is a technique that was created in 1979 by Doctor Kenzo Kase I’m looking through it that could generate a new therapeutic option to control pain, improve athletic performance and reduce the impact of musculoskeletal disorders. From the Sydney 2000 Olympic Games, this technique as a therapeutic alternative PTO and is composed of health professionals in the field of sport and physical rehabilitation.Objetive: This article aims to identify theoretical approaches on the bandage neuromuscular. Material and methods: held today, for which conducted a literature search of databases such as como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs.The paper proposes a scheme of contextualization of the current landscape of the use and effects of kinesio taping in the management of different pathologies of the musculo-skeletal system in sports. Conclusion: it is concluded that currently many health professionals, and take the neuromuscular bandage a good therapeutic option in the management of diseases affecting the human body is investigated and every day more about the subject, which makes these new therapeutic methods to acquire a scientific value and transcends knowledge.

Calero PA

2012-05-01

113

Neuromuscular complications of nutritional deficiencies.  

Science.gov (United States)

For many nutrition deficiencies, a direct cause and effect of different symptoms and diseases has been established. These are known as primary nutritional deficiencies. Secondary deficiencies occur when the vitamin or nutrient requirement may be increased, such as in patients who have pernicious anemia who lack the intrinsic factor needed to absorb vitamin B12. Less well recognized are the effects of nutritional deficiencies on chronic disease, especially acute and chronic neuromuscular diseases. This article identifies some of the causative factors and provides the reader with a guideline for what to consider in the evaluation of individuals who have neuromuscular problems. The context of these disorders is best understood on a foundation of basic nutrition information. PMID:18194754

Williams, Faren H

2008-02-01

114

Cognitive impairment in neuromuscular disorders.  

Science.gov (United States)

Several studies have suggested the presence of central nervous system involvement manifesting as cognitive impairment in diseases traditionally confined to the peripheral nervous system. The aim of this review is to highlight the character of clinical, genetic, neurofunctional, cognitive, and psychiatric deficits in neuromuscular disorders. A high correlation between cognitive features and cerebral protein expression or function is evident in Duchenne muscular dystrophy, myotonic dystrophy (Steinert disease), and mitochondrial encephalomyopathies; direct correlation between tissue-specific protein expression and cognitive deficits is still elusive in certain neuromuscular disorders presenting with or without a cerebral abnormality, such as congenital muscular dystrophies, congenital myopathies, amyotrophic lateral sclerosis, adult polyglucosan body disease, and limb-girdle muscular dystrophies. No clear cognitive deficits have been found in spinal muscular atrophy and facioscapulohumeral dystrophy. PMID:16544320

D'Angelo, Maria Grazia; Bresolin, Nereo

2006-07-01

115

Degeneration of Neuromuscular Junction in Age and Dystrophy  

Directory of Open Access Journals (Sweden)

Full Text Available Functional denervation is a hallmark of aging sarcopenia as well as of muscular dystrophy. It is thought to be a major factor reducing skeletal muscle mass, particularly in the case of sarcopenia. Neuromuscular junctions serve as the interface between the nervous and skeletal muscular systems, and thus they may receive pathophysiological input of both pre- and postsynaptic origin. Consequently, neuromuscular junctions are good indicators of motor health on a systemic level. Indeed, upon sarcopenia and dystrophy, neuromuscular junctions morphologically deteriorate and exhibit altered characteristics of primary signaling molecules, such as nicotinic acetylcholine receptor and agrin. Since a remarkable reversibility of these changes can be observed by exercise, there is significant interest in understanding the molecular mechanisms underlying synaptic deterioration upon aging and dystrophy and how synapses are reset by the aforementioned treatments. Here, we review the literature that describes the phenomena observed at the neuromuscular junction in sarcopenic and dystrophic muscle as well as to how these alterations can be reversed and to what extent. In a second part, the current information about molecular machineries underlying these processes is reported.

Rüdiger Rudolf

2014-05-01

116

Maintenance of BWR control rod drive mechanisms.  

Science.gov (United States)

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 Nati...

R. H. Greene

1991-01-01

117

21 CFR 882.5810 - External functional neuromuscular stimulator.  

Science.gov (United States)

...2010-04-01 2010-04-01 false External functional neuromuscular stimulator...Therapeutic Devices § 882.5810 External functional neuromuscular stimulator. (a) Identification. An external functional neuromuscular...

2010-04-01

118

Damage-mitigating control of mechanical systems  

Science.gov (United States)

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

Holmes, Michael S.

119

Neuromuscular blocking effect of fluoxetine and its interaction with rocuronium.  

Science.gov (United States)

As selective serotonin reuptake inhibitors have an inhibitory effect on nicotinic acetylcholine receptors, they may affect the neuromuscular transmission and interact with neuromuscular blockers. This study was designed to observe the effect of fluoxetine on neuromuscular transmission and its interaction with rocuronium using the rat phrenic nerve hemidiaphragm and rabbit head drop methods. Rat phrenic nerve hemidiaphragms were mounted and stimulated using a train of four pulses (TOF). The effect of fluoxetine was studied on both indirectly and directly stimulated basal twitch responses by plotting cumulative dose response curves (DRCs). DRCs of rocuronium were obtained in the absence, and presence of 5 ?m and 20 ?m fluoxetine to study its interaction. ED5 , ED50 and ED95 values of rocuronium DRCs in absence and presence of fluoxetine were calculated. Fluoxetine significantly inhibited twitch responses in both indirect and directly stimulated preparations. Fluoxetine (20 ?m) caused an increase in the potency of rocuronium such that the ED50 and ED95 values of rocuronium DRCs were significantly decreased. Partially inhibited twitch responses by fluoxetine (100 ?m) were not reversed by neostigmine (3.3 ?m) or 3,4 diaminopyridine (0.25 ?m). Rabbits were given fluoxetine 0.25 mg kg(-1) and 1 mg kg(-1) orally for 15 days, and on 15th day, rocuronium infusion was given, and time for head drop was recorded. The time of head drop was significantly reduced in fluoxetine pretreated as compared to control group. Fluoxetine blocks the neuromuscular transmission and increases the potency of rocuronium-induced neuromuscular block. PMID:23461555

Patel, J C; Barvaliya, M J; Patel, T K; Tripathi, C B

2013-04-01

120

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.

 
 
 
 
121

Functional penetration of variability of motor neuron spike timing through a modulated neuromuscular system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Variability of the neuronal spike pattern is usually thought of in terms of the information that the different interspike intervals might be encoding. However, the very presence of the variability can have other kinds of functional significance. Here we consider the example of the B15/B16-ARC neuromuscular system of Aplysia, a model system for the study of neuromuscular modulation and control. We show that variability of motor neuron spike timing at the input to the system penetrates througho...

Brezina, Vladimir

2007-01-01

122

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.

2007-07-18

123

Operation of Control Rod Driving Mechanism controller at HANARO  

Energy Technology Data Exchange (ETDEWEB)

HANARO (High flux Advanced Neutron Application Reactor) achieved its first critical operation in 1995. Recently, there has been fast developments in the field of electronics. Many manufacturers of I and C components have disappeared or merged with the other companies. The suppliers of the control systems of the CRDM (Control Rod Driving Mechanism) at HANARO have disappeared. Therefore, we needed to change the control system of the CRDM since we cannot be provided with maintenance any longer. In this paper, we investigated the operation of the control system of the CRDM when the controller and motor driver are changed.

Gyu, Doo Seung; Woo, Lee Min; San, Choe Yeong; Kyoo, Kim Hyung [KAERI, Daejeon (Korea, Republic of)

2012-10-15

124

Operation of Control Rod Driving Mechanism controller at HANARO  

International Nuclear Information System (INIS)

HANARO (High flux Advanced Neutron Application Reactor) achieved its first critical operation in 1995. Recently, there has been fast developments in the field of electronics. Many manufacturers of I and C components have disappeared or merged with the other companies. The suppliers of the control systems of the CRDM (Control Rod Driving Mechanism) at HANARO have disappeared. Therefore, we needed to change the control system of the CRDM since we cannot be provided with maintenance any longer. In this paper, we investigated the operation of the control system of the CRDM when the controller and motor driver are changed

125

Neuromuscular impairment following backpack load carriage.  

Science.gov (United States)

Load Carriage using backpacks is an occupational task and can be a recreational pursuit. The aim of this study was to investigate the mechanisms responsible for changes in neuromuscular function of the m. quadriceps femoris following load carriage. The physiological responses of 10 male participants to voluntary and electrically stimulated isometric contractions were measured before and immediately after two hours of treadmill walking at 6.5 km•h(-1) during level walking with no load [LW], and level walking with load carriage (25 kg backpack) [LC]. Maximal voluntary contraction force decreased by 15 ± 11 % following LC (p=0.006), with no change following LW (p=0.292). Voluntary activation decreased after LW and LC (p=0.033) with no difference between conditions (p=0.405). Doublet contraction time decreased after both LW and LC (p=0.002), with no difference between conditions (p=0.232). There were no other changes in electrically invoked doublet parameters in either condition. The 20:50 Hz ratio did not change following LW (p=0.864) but decreased from 0.88 ± 0.04 to 0.84 ± 0.04 after LC (p=0.011) indicating reduced Ca2+ release from the sarcoplasmic reticulum during excitation contraction coupling. In conclusion, two hours of load carriage carrying a 25 kg back pack caused neuromuscular impairment through a decrease in voluntary activation (i.e. central drive) and fatigue or damage to the peripheral muscle, including impairment of the excitation contraction coupling process. This may reduce physical performance and increase the risk of musculoskeletal injury. PMID:24146709

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

2013-01-01

126

Remote controlled vacuum joint closure mechanism  

Science.gov (United States)

A remotely operable and maintainable vacuum joint closure mechanism for a noncircular aperture is disclosed. The closure mechanism includes an extendible bellows coupled at one end to a noncircular duct and at its other end to a flange assembly having sealed grooves for establishing a high vacuum seal with the abutting surface of a facing flange which includes an aperture forming part of the system to be evacuated. A plurality of generally linear arrangements of pivotally coupled linkages and piston combinations are mounted around the outer surface of the duct and aligned along the length thereof. Each of the piston/linkage assemblies is adapted to engage the flange assembly by means of a respective piston and is further coupled to a remote controlled piston drive shaft to permit each of the linkages positioned on a respective flat outer surface of the duct to simultaneously and uniformly displace a corresponding piston and the flange assembly with which it is in contact along the length of the duct in extending the bellows to provide a high vacuum seal between the movable flange and the facing flange. A plurality of latch mechanisms are also pivotally mounted on the outside of the duct. A first end of each of the latch mechanisms is coupled to a remotely controlled latch control shaft for displacing the latch mechanism about its pivot point. In response to the pivoting displacement of the latch mechanism, a second end thereof is displaced so as to securely engage the facing flange.

Doll, David W. (San Diego, CA); Hager, E. Randolph (La Jolla, CA)

1986-01-01

127

36 CFR 1193.41 - Input, control, and mechanical functions.  

Science.gov (United States)

...2010-07-01 2010-07-01 false Input, control, and mechanical functions. 1193.41...Accessibility and Usability § 1193.41 Input, control, and mechanical functions. Input, control, and mechanical functions shall be...

2010-07-01

128

14 CFR 29.691 - Autorotation control mechanism.  

Science.gov (United States)

...2010-01-01 false Autorotation control mechanism. 29.691 Section 29.691 Aeronautics...Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow rapid entry into autorotation...

2010-01-01

129

14 CFR 27.691 - Autorotation control mechanism.  

Science.gov (United States)

...2010-01-01 false Autorotation control mechanism. 27.691 Section 27.691 Aeronautics...Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow rapid entry into autorotation...

2010-01-01

130

Evaluations of neuromuscular dynamics of hyperactive reflexes poststroke  

Directory of Open Access Journals (Sweden)

Full Text Available Tendon reflexes are widely used in clinics to conveniently evaluate various neurological disorders. This study characterized neuromuscular dynamics of tendon reflexes at the elbow with multiple quantitative measures in both patients with stroke and nondisabled controls. We employed a handheld instrumented hammer to tap the triceps muscle tendon at various elbow flexion angles and measured the tapping force, triceps electromyography, and elbow extension torque to characterize neuromuscular dynamics of tendon reflexes quantitatively in terms of the tendon reflex gain, contraction rate, half relaxation rate, reflex loop delay, and reflex threshold in tapping force. We found that the tendon reflex gain, contraction rate, and half relaxation rate were significantly higher while the reflex threshold was significantly lower across different joint angles in patients with stroke than in nondisabled controls (p < 0.05, indicating hyperactive neurological state and muscle contraction dynamics poststroke. This study presents a convenient and quantitative method to evaluate reflex excitability and muscle contraction dynamics.

Jie Liu, BS

2011-05-01

131

[Epidemiology of adult neuromuscular disorders].  

Science.gov (United States)

The percentage and cause of neuromuscular (NM) diseases have been analysed during a 15-year period of time. A NM disorder was found in 10,852 patients (or 14.4% of all neurological patients seen in our hospital). Mononeuropathies have been the most common causes, followed by polyneuropathies and radiculopathies, but with a variable percentage during time for the most frequent causes, that were carpal tunnel syndrome and diabetic polyneuropathies. Myopathies, diseases of the neuromuscular junction and anterior horn cell disorders counted for 5% among all NM disorders during the first 10 years (1% of all neurological patients) and for 12% during the last 5 years (2.4% of all neurological patients), this period corresponds to the opening of our outpatient clinic dedicated to NM diseases. Among polyneuropathies, the most common causes were diabetes mellitus, chronic inflammatory demyelinating polyneuropathies and the inherited forms of peripheral neuropathies. Among myopathies, the most frequently reported symptom was exercise-induced myalgia. The 2 most common muscular dystrophies (MD) were Steinert myotonic MD, and facio-scapulo-humeral MD. Other myopathies were rare, but of diverse causes, all of them corresponding to the newly introduced definition of Rare or Orphan Diseases. PMID:11094537

Kuntzer, T; Lettry-Trouillat, R; Bogousslavsky, J

2000-09-01

132

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

133

Neuromuscular physiology of Hymenolepis diminuta and H. microstoma (Cestoda).  

Science.gov (United States)

The physiology of the neuromuscular systems in Hymenolepis diminuta and H. microstoma was studied in vitro using intact, adult worm and strips of worm body wall. Intact worms were insensitive to ionic changes in the in vitro buffering system. However, strips of body wall containing longitudinal muscles were extremely sensitive to ionic manipulation. In intact worms tension generated in the strobila had two components; small brief tension peaks up to 500 mg amplitude are superimposed on larger, longer peaks of up to 1200 mg amplitude. Removal of the scolex and neck region either failed to show significant changes in tension, or showed a reduction in amplitude but not of frequency. Muscle contraction of both H. diminuta and H. microstoma were qualitatively similar. In split-worm preparations the concentration of Ca2+ in the bathing solution significantly affected both spontaneous and evoked contractions in H. diminuta and H. microstoma; the addition of CaCl2 greatly reduced the amplitude and frequency of the contractions. The chloride salts of cobalt, barium, cadmium and manganese elicited prolonged contractions of the longitudinal musculature of both H. diminuta and H. microstoma. While CoCl2 was the most effective in stimulating muscle contraction, the magnitude of the response varied with the concentration of Ca2+ in the bath. The results indicate that peripheral inhibition is extremely important in cestode motor control and that extracellular calcium ions may regulate the peripheral inhibitory mechanisms. PMID:6440096

Thompson, C S; Mettrick, D F

1984-12-01

134

Advances in neuromuscular disease 2003: the year in review.  

Science.gov (United States)

During 2003, numerous research advances in both clinical neuromuscular disease and in the basic pathophysiology of these disorders were published and/or presented. In this review, we present a few categorical highlights of the year, discussing a new potential treatment of McArdle's disease, proposed new diagnostic criteria for the inflammatory myopathies and their clinical implications, the emerging anti-MuSK antibody syndrome in patients with myasthenia gravis, potential new therapies for the most common hereditary neuropathy (Charcot-Marie-Tooth type 1A), the successful pharmacologic manipulation and its therapeutic implications of the genetic mechanisms underlying spinal muscular atrophy, and several emerging therapeutic strategies in amyotrophic lateral sclerosis. As these reports indicate, clinical and basic research in neuromuscular disease continues to yield important and clinically relevant insights, which are now being rapidly translated into new clinical trials showing therapeutic promise for diseases previously thought untreatable. PMID:19078738

Alexianu, Maria E; Gooch, Clifton L

2004-06-01

135

Efectos del vendaje neuromuscular: una revisión bibliográfica / Neuromuscular dressing effects: a literature review / Efeitos neuromusculares de bandages: uma revisão da literatura  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in portuguese A kinesio taping é uma técnica que foi criada em 1979 por Dr. Kenzo Kase Estou procurando através dele que poderia gerar uma nova opção terapêutica para controlar a dor, melhorar o desempenho atlético e reduzir o impacto de distúrbios músculo-esqueléticos. Do Sydney 2000 Olympic Games, estatécnica c [...] omo uma alternativa terapêutica PTO e é composto de profissionais de saúde na área de reabilitação física e esporte. Alvo: Este artigo tem como objetivo identificar abordagens teóricas sobre oNeuromuscular curativo. Materiais e métodos: realizou hoje, para o qual realizou uma pesquisa bibliográficados bancos de dados, tais como como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs). O documento propõe um esquemade contextualização do cenário atual do uso e efeitos de kinesio taping na gestão dasdiferentes patologias do sistema músculo-esquelético no esporte. Conclusões: conclui-se quemuitos profissionais de saúde atualmente, e tomar as vandaje neuromuscular uma boa opção terapêutica no tratamento de doenças que afetam o corpo humano é investigada e cada dia mais sobre o assunto, o que torna esses novos métodosterapêuticos para adquirir um valor científico e transcende o conhecimento. Abstract in spanish El vendaje neuromuscular es una técnica creada en 1979 por el doctor Kenzo Kase, quien buscó proponer una nueva opción terapéutica para controlar el dolor, mejorar el rendimiento deportivo y reducir el impacto de los trastornos musculo-esqueléticos. A partir de los Juegos Olímpicos de Sydney 2000 es [...] ta técnica empleada por los profesionales de la salud en el campo del deporte y la rehabilitación física tomó fuerza como alternativa terapéutica. Objetivo: identificar las aproximaciones teóricas sobre el vendaje neuromuscular realizadas en la actualidad. Materiales y métodos: se llevó a cabo una búsqueda bibliográfica en bases de datos como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs). El esquema del artículo propone una contextualización del panorama actual del uso y los efectos del vendaje neuromuscular en el campo deportivo y en el manejo de diferentes patologías del sistema musculo-esquelético. Conclusiones: se concluye que actualmente muchos profesionales de la salud toman el vendaje neuromuscular como un buena opción terapéutica en el manejo de patologías que afectan el cuerpo humano, por lo cual cada día se investiga más acerca del tema, otorgando un valor científico a estos nuevos métodos. Abstract in english The kinesio taping is a technique that was created in 1979 by Doctor Kenzo Kase I'm looking through it that could generate a new therapeutic option to control pain, improve athletic performance and reduce the impact of musculoskeletal disorders. From the Sydney 2000 Olympic Games, this technique as [...] a therapeutic alternative PTO and is composed of health professionals in the field of sport and physical rehabilitation. Objetive: This article aims to identify theoretical approaches on the bandage neuromuscular. Material and methods: held today, for which conducted a literature search of databases such as como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs). The paper proposes a scheme of contextualization of the current landscape of the use and effects of kinesio taping in the management of different pathologies of the musculo-skeletal system in sports. Conclusion: it is concluded that currently many health professionals, and take the neuromuscular bandage a good therapeutic option in the management of diseases affecting the human body is investigated and every day more about the subject,

Pedro Antonio, Calero Saa; Gustavo Adolfo, Cañón Martínez.

136

Efectos del vendaje neuromuscular: una revisión bibliográfica / Neuromuscular dressing effects: a literature review / Efeitos neuromusculares de bandages: uma revisão da literatura  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in portuguese A kinesio taping é uma técnica que foi criada em 1979 por Dr. Kenzo Kase Estou procurando através dele que poderia gerar uma nova opção terapêutica para controlar a dor, melhorar o desempenho atlético e reduzir o impacto de distúrbios músculo-esqueléticos. Do Sydney 2000 Olympic Games, estatécnica c [...] omo uma alternativa terapêutica PTO e é composto de profissionais de saúde na área de reabilitação física e esporte. Alvo: Este artigo tem como objetivo identificar abordagens teóricas sobre oNeuromuscular curativo. Materiais e métodos: realizou hoje, para o qual realizou uma pesquisa bibliográficados bancos de dados, tais como como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs). O documento propõe um esquemade contextualização do cenário atual do uso e efeitos de kinesio taping na gestão dasdiferentes patologias do sistema músculo-esquelético no esporte. Conclusões: conclui-se quemuitos profissionais de saúde atualmente, e tomar as vandaje neuromuscular uma boa opção terapêutica no tratamento de doenças que afetam o corpo humano é investigada e cada dia mais sobre o assunto, o que torna esses novos métodosterapêuticos para adquirir um valor científico e transcende o conhecimento. Abstract in spanish El vendaje neuromuscular es una técnica creada en 1979 por el doctor Kenzo Kase, quien buscó proponer una nueva opción terapéutica para controlar el dolor, mejorar el rendimiento deportivo y reducir el impacto de los trastornos musculo-esqueléticos. A partir de los Juegos Olímpicos de Sydney 2000 es [...] ta técnica empleada por los profesionales de la salud en el campo del deporte y la rehabilitación física tomó fuerza como alternativa terapéutica. Objetivo: identificar las aproximaciones teóricas sobre el vendaje neuromuscular realizadas en la actualidad. Materiales y métodos: se llevó a cabo una búsqueda bibliográfica en bases de datos como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs). El esquema del artículo propone una contextualización del panorama actual del uso y los efectos del vendaje neuromuscular en el campo deportivo y en el manejo de diferentes patologías del sistema musculo-esquelético. Conclusiones: se concluye que actualmente muchos profesionales de la salud toman el vendaje neuromuscular como un buena opción terapéutica en el manejo de patologías que afectan el cuerpo humano, por lo cual cada día se investiga más acerca del tema, otorgando un valor científico a estos nuevos métodos. Abstract in english The kinesio taping is a technique that was created in 1979 by Doctor Kenzo Kase I'm looking through it that could generate a new therapeutic option to control pain, improve athletic performance and reduce the impact of musculoskeletal disorders. From the Sydney 2000 Olympic Games, this technique as [...] a therapeutic alternative PTO and is composed of health professionals in the field of sport and physical rehabilitation. Objetive: This article aims to identify theoretical approaches on the bandage neuromuscular. Material and methods: held today, for which conducted a literature search of databases such as como Proquest, Ovid, Cochraine, PEDro, Journal of Orthopedic and Sports Physical, Sciencedirect, Pubmed y Literatura Latinoamericana y del Caribe en Ciencias de la Salud (Lilacs). The paper proposes a scheme of contextualization of the current landscape of the use and effects of kinesio taping in the management of different pathologies of the musculo-skeletal system in sports. Conclusion: it is concluded that currently many health professionals, and take the neuromuscular bandage a good therapeutic option in the management of diseases affecting the human body is investigated and every day more about the subject,

Pedro Antonio, Calero Saa; Gustavo Adolfo, Cañón Martínez.

2012-08-01

137

Mechanisms controlling division-plane positioning.  

Science.gov (United States)

A critical and irreversible step in the cell division cycle is cytokinesis which physically separates the two daughter cells. This event is consequently subject to tight spatial and temporal regulation. This review focuses on the spatial regulatory mechanisms controlling the position of the division plane. Studies performed in prokaryotic and eukaryotic systems have revealed that various signal-emitting spatial cues - mitotic spindle, nucleus, nucleoid or cell tips - can favour or inhibit the assembly of the cytokinetic apparatus in their vicinity. Most often, several mechanisms operate in parallel to integrate spatial information and promote faithful genome segregation as well as proper cytoplasmic division. We primarily describe the spatial regulatory mechanisms operating in the fission yeast model system, where a detailed molecular understanding of cytokinesis has been achieved. In this system, spatial regulations target a major factor controlling the position of the division plane, the anillin-like protein Mid1. These mechanisms are then compared to spatial regulatory mechanisms prevailing in animal cells and rod-shaped bacteria. PMID:20708089

Almonacid, Maria; Paoletti, Anne

2010-12-01

138

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

139

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

140

Control mechanisms for Nordic ship emissions  

Energy Technology Data Exchange (ETDEWEB)

Shipping today operates under a complex set of international and domestic regulations. However, the environmental regulations have lagged behind those of other industries. This situation is now changing quite dramatically. The increased focus on environmental issues, combined with the growing realisation of the actual pollution burden imposed by shipping, has led to an upsurge in both international and national regulations. Some are ready and will enter into force in the near future, while others are still being developed. On behalf of the Nordic Council of Ministers DNV has carried out a study on possible control mechanisms for Nordic ship emission. The aim is to assess the baseline shipping emissions and reduction potential and the possible controlling mechanisms (both incentives and regulations) available for reducing the emissions to air from shipping within the Nordic region. (Author)

Martinsen, K. [DNV, Oslo (Norway); Torvanger, A. [Cicero, Oslo (Norway)

2013-04-15

 
 
 
 
141

Neuromuscular and biomechanical landing performance subsequent to ipsilateral semitendinosus and gracilis autograft anterior cruciate ligament reconstruction.  

Science.gov (United States)

The hamstrings musculature is a vital component of an intricate dynamic knee joint restraint mechanism. However, there is evidence based on research studies suggesting potential deficits to this complex mechanism due to donor site morbidity resulting from harvest of the ipsilateral semitendinosus and gracilis autograft (ISGA) for anterior cruciate ligament reconstruction (ACLR). The purpose of this retrospective research study was to investigate the effects of ISGA ACLR on neuromuscular and biomechanical performance during a single-leg vertical drop landing (VDL), a functional task and associated mechanism of anterior cruciate ligament disruption during physical activity. Fourteen physically active participants 22.5 +/- 4.1 years of age and 21.4 +/- 10.7 months post ISGA ACLR underwent bilateral neuromuscular, biomechanical and isokinetic strength and endurance evaluations matched to 14 control participants by sex, age, height and mass. Kinetic and kinematic data was obtained with 3-D motion analyses utilizing inverse dynamics while performing single-leg VDLs from a height of 30 cm. Integrated surface electromyography (SEMG) assessments of the quadriceps, hamstrings and gastrocnemius musculature were also conducted. Additionally, knee joint flexion strength (60 degrees s(-1)) and endurance (240 degrees s(-1)) measurements were tested via isokinetic dynamometry. No significant differences existed in hip and net summated extensor moments within or between groups. The ISGA ACLR participants recorded significantly decreased peak vertical ground reaction force (VGRF) landing upon the involved lower extremity compared to uninvolved (P = 0.028) and matched (P < 0.0001) controls. Participants having undergone ISGA ACLR also displayed greater peak hip joint flexion angles landing upon the involved lower extremity compared to uninvolved (P = 0.020) and matched (P = 0.026) controls at initial ground contact. The ISGA ACLR group furthermore exhibited increased peak hip joint flexion angles landing upon the involved lower extremity compared to uninvolved (P = 0.019) and matched (P = 0.007) controls at peak VGRF. Moreover, ISGA ALCR participants demonstrated greater peak knee (P = 0.005) and ankle (P = 0.017) joint flexion angles when landing upon the involved lower extremity compared to the matched control at peak VGRF. The ISGA ACLR group produced significantly greater reactive muscle activation of the vastus medialis (P = 0.013), vastus lateralis (P = 0.008) and medial hamstrings (P = 0.024) in the involved lower extremity compared to the matched control. The ISGA ACLR participants also exhibited greater preparatory (P = 0.033) and reactive (P = 0.022) co-contraction muscle activity of the quadriceps and hamstrings landing upon the involved lower extremity compared to the matched control. In addition, the ISGA ACLR group produced significantly less preparatory (P = 0.005) and reactive (P = 0.010) muscle activation of the gastrocnemius in the involved lower extremity compared to the uninvolved control. No significant differences were present in hamstrings muscular strength and endurance. Harvest of the ISGA for purposes of ACLR does not appear to result in significant neuromuscular, biomechanical or strength and endurance deficiencies due to donor site morbidity. However, it is evident that this specific population exhibits unique neuromuscular and biomechanical adaptations aimed to stabilize the knee previously subjected to ACL trauma and safeguard the ISGA ACLR joint. Co-contraction of quadriceps and hamstrings as well as inhibition of gastrocnemius muscle activation may serve to moderate excessive loads exposed to the intra-articular ISGA during single-leg VDLs. Furthermore, greater muscle activation of the hamstrings in conjunction with increased peak hip, knee and ankle joint flexion angles may assist in enhancing acceptance of VGRF transferred through the kinetic chain following single-leg VDLs. PMID:17973098

Vairo, Giampietro L; Myers, Joseph B; Sell, Timothy C; Fu, Freddie H; Harner, Christopher D; Lephart, Scott M

2008-01-01

142

Neuromuscular interactions around the knee in children, adults and elderly  

Science.gov (United States)

Although injury and neuromuscular activation patterns may be common for all individuals, there are certain factors which differentiate neuromuscular activity responses between children, adults and elderly. The purpose of this study is to review recent evidence on age differences in neural activation and muscle balances around the knee when performing single joint movements. Particularly, current evidence indicates that there are some interesting similarities in the neuromuscular mechanisms by which children or the elderly differ compared with adults. Both children and elderly display a lower absolute muscle strength capacity than adults which cannot fully be explained by differences in muscle mass. Quadriceps activation failure is a common symptom of all knee injuries, irrespective of age but it is likely that its effect is more evident in children or adults. While one might expect that antagonist co-activation would differ between age categories, it appears that this is not the case. Although hamstring: quadriceps ratio levels are altered after knee injury, it is not clear whether this is an age specific response. Finally, evidence suggests that both children and the elderly display less stiffness of the quadriceps muscle-tendon unit than adults which affects their knee joint function. PMID:25232523

Kellis, Eleftherios; Mademli, Lida; Patikas, Dimitrios; Kofotolis, Nikolaos

2014-01-01

143

Neuromuscular interactions around the knee in children, adults and elderly.  

Science.gov (United States)

Although injury and neuromuscular activation patterns may be common for all individuals, there are certain factors which differentiate neuromuscular activity responses between children, adults and elderly. The purpose of this study is to review recent evidence on age differences in neural activation and muscle balances around the knee when performing single joint movements. Particularly, current evidence indicates that there are some interesting similarities in the neuromuscular mechanisms by which children or the elderly differ compared with adults. Both children and elderly display a lower absolute muscle strength capacity than adults which cannot fully be explained by differences in muscle mass. Quadriceps activation failure is a common symptom of all knee injuries, irrespective of age but it is likely that its effect is more evident in children or adults. While one might expect that antagonist co-activation would differ between age categories, it appears that this is not the case. Although hamstring: quadriceps ratio levels are altered after knee injury, it is not clear whether this is an age specific response. Finally, evidence suggests that both children and the elderly display less stiffness of the quadriceps muscle-tendon unit than adults which affects their knee joint function. PMID:25232523

Kellis, Eleftherios; Mademli, Lida; Patikas, Dimitrios; Kofotolis, Nikolaos

2014-09-18

144

On the operating mechanism of population control.  

Science.gov (United States)

The progress made in population control in China is accounted for. The ingredients are a sound operating system (a mechanism), sufficient motivation, adequate and appropriate funding, information dissemination which dispels health fears and extols the health benefits, and a breakdown of social barriers to birth control. The mechanism takes into account the facts that individuals make choices about birth control and should have sufficient motivation and that the costs to society and individuals should be acceptable. Birth control will succeed when the motivation is strong and costs are reasonable. Even forced implementation will not work when costs are high and motivation weak. The current Chinese mechanism is not adequate to deal with new problems arising from reform and an opening up to the Western world. A parent's motivation is a result of supply and demand under certain conditions. The ability to produce children is related to the maximum parity under no restrictions and the probability of survival. Policy interventions must be directed to increasing the gap between supply and demand by influencing a parent's desire for more children. This desire is influenced by number, gender, and birth intervals as well as by educational and occupational goals. Son preference will increase the demand for more children. The economic value of children, resources available for raising children, and a subjective value judgement also influence the desire for children. Parental decisions may not be well-founded. The purpose of the policy is to establish minimum age requirements for employment and job-training programs and to provide old age security with greater benefits to those practicing birth control. Campaigns should be conducted to convince people to have small families. The long-term cost effectiveness of the IUD and sterilization means a wise investment. Funding has been increased to 2 yuan/person to account for the expansion of the program in breadth and depth. Misconceptions about the cost to health through side effects can be dispelled through campaigns and appropriate targets. PMID:12286125

Wei, J

1992-01-01

145

Automatic control mechanism for nuclear reactor scram  

International Nuclear Information System (INIS)

A mechanism is described in which the mean temperature of the coolant on leaving the core of a liquid cooled nuclear reactor is detected and which allows a poison to fall quickly into the core of the reactor when a critical temperature is reached. The reactor comprises a safety pipe located in the core and rising above it, a vertical flow path for the reactor coolant passing through the pipe and a poison bundle absorbing the neutrons, retained by a supporting system. Several fuel rods are located in the flow path of the coolant, a temperature sensitive control device is located in the flow path near the upper end of the fuel rods, a retaining device is fitted between the poison bundle support system and the control system so as to release the poison bundle when the control system makes a preset movement

146

Hazard factors of ACL rupture: Neuromuscular factors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

147

Neuromuscular Electrical Stimulation for Skeletal Muscle Function  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Lack of neural innervation due to neurological damage renders muscle unable to produce force. Use of electrical stimulation is a medium in which investigators have tried to find a way to restore movement and the ability to perform activities of daily living. Different methods of applying electrical current to modify neuromuscular activity are electrical stimulation (ES), neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), and functional electrical ...

Doucet, Barbara M.; Lam, Amy; Griffin, Lisa

2012-01-01

148

Temporal structure of variability reveals similar control mechanisms during lateral stepping and forward walking.  

Science.gov (United States)

Previous research exploring a lateral stepping gait utilized amount of variability (i.e. coefficient of variation) in the medial-lateral (ML) and anterior-posterior (AP) direction to propose that the central nervous system's active control over gait in any direction is dependent on the direction of progression. This study sought to further explore this notion through the study of the temporal structure of variability which is reflective of the neuromuscular system's organization of the movement over time. The largest Lyapunov exponent (LyE) of the reconstructed attractors for the foot's movement in the AP and ML was calculated. Results revealed that despite the obvious mechanical differences between a lateral stepping gait and typical forward walking, the central nervous system's organization of the movement of the feet is similar in the primary planes of progression, as well as the secondary planes of progression, despite being different anatomical planes during the locomotive tasks. In addition, consistent with previous studies exploring amount of variability, the secondary plane for both locomotive tasks proved to have larger LyE values than the primary plane of progression (F1,9=35.086, p<0.001). This is consistent with less dependency from stride-to-stride in the secondary plane implying increased active control. PMID:23245640

Wurdeman, Shane R; Stergiou, Nicholas

2013-05-01

149

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

150

Relaxofon: a neuromuscular blockade monitor for patients under general anesthesia.  

Science.gov (United States)

Anesthesia consists of three components: unconsciousness, analgesia and neuromuscular blockade (NMB). A specific drug is administered by the anesthesiologist to control these different components. In this paper we propose a new system for monitoring the neuromuscular blockade in anesthesized patients during surgery. Neuromuscular blockade drugs are used routinely by clinicians to induce muscle relaxation in patients. However, the use of these drugs has some risks, so an adequate monitoring of the effects of these drugs is essential. This paper describes the Relaxofon, a NMB monitoring device based on phonomyography. The Relaxofon is composed of a hardware subsystem that records muscle sounds using microphones and a special circuit to filter out the noise and amplify the signal, and a software subsystem that analyses the acquired signal. We tested the ability of the system to record phonomyographic signals from the adductor pollicis and the corrugator supercilii muscles. We then performed the Bland-Altman test to compare the manual Train-of-Four ratio (a measure of the depth of muscle relaxation) calculation against the one performed by the Relaxofon. Finally, we calculated the Pearson correlation coefficient to measure the linear dependence between the two methods. Automatic Train-of-Four ratio calculations using this system showed very good agreement with manual calculations. Results from this work may ultimately lead to integration of NMB monitoring to an automated closed-loop anesthesia system. PMID:23365854

Wehbe, Mohamad; Mathieu, Pierre A; Hemmerling, Thomas M

2012-01-01

151

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

152

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

153

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)

154

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

155

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

156

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Management of acute respiratory distress syndrome (ARDS) in the intensive care unit (ICU) is clinically challenging and costly. Neuromuscular blocking agents may facilitate mechanical ventilation and improve oxygenation, but may result in prolonged recovery of neuromuscular function and acute quadriplegic myopathy syndrome (AQMS). The goal of this study was to address a hypothetical question via computer modeling: Would a reduction in intubation time of 6 ...

Chow John L; Macario Alex; Dexter Franklin

2006-01-01

157

Electrochemical biofilm control: mechanism of action  

Science.gov (United States)

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 could not be detected in the bulk solution. The goals of this research were (1) to develop a well-controlled system to explain the mechanism of action of the bioelectrochemical effect on 316L stainless steel (SS) surfaces and (2) to test whether the produced H2O2 can reduce cell growth on metal surfaces. It was found that H2O2 was produced near 316L SS surfaces when a negative potential was applied. The H2O2 concentration increased towards the surface, while the dissolved oxygen decreased when the SS surface was polarized to ?600 mVAg/AgCl. When polarized and non-polarized surfaces with identical Pseudomonas aeruginosa PAO1 biofilms were continuously fed with air-saturated growth medium, the polarized surfaces showed minimal biofilm growth while there was significant biofilm growth on the non-polarized surfaces. Although there was no detectable H2O2 in the bulk solution, it was found that the surface concentration of H2O2 was able to prevent biofilm growth. PMID:22827804

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

2014-01-01

158

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; Andersen, Ole Trier

1997-01-01

159

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.

160

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

 
 
 
 
161

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

162

Controlling fugitive emissions from mechanical seals  

International Nuclear Information System (INIS)

This paper reports that enactment of the 1990 Federal Clean Air Amendments will sharply focus efforts in the process industries to reduce fugitive emissions. Moreover, state and local governments may be imposing stricter laws and regulations which will affect allowable fugitive emissions from U.S. refineries and process plants. Plants outside the U.S. have similar concerns. Clearly, mechanical seals for process pumps represent an enormous population and is one category of equipment destined for careful evaluation as a means to control fugitive emissions. Fugitive are unintentional emissions from valves, pumps, flanges, compressors, etc., as opposed to point-source emissions from stacks, vents and flares. Fugitive emissions do not occur as a part of normal plant operations, but result from the effects of: Malfunctions, Age, Lack of proper maintenance, Operator error, Improper equipment specification, Use of inferior technology, and externally caused damage

163

Moderate Aging Does Not Modulate Morphological Responsiveness of the Neuromuscular System to Chronic Overload in Fischer 344 Rats  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this investigation was to determine the effect of aging on neuromuscular adaptations to chronic overload. Eight young adult (8 mo old) and eight aged (22 mo old) Fischer 344 rats underwent unilateral synergist ablation to overload the plantaris and soleus muscles of that hindlimb and to provide control muscles from the contralateral hindlimb. Cytofluorescent staining and confocal microscopy were used to quantify pre- and post-synaptic features of neuromuscular junctions (NMJs)....

Deschenes, Michael R.; Tenny, Kelly; Eason, Margaret K.; Gordon, Scott E.

2007-01-01

164

Neuromuscular blocking activity of pinnatoxins E, F and G.  

Science.gov (United States)

Pinnatoxins are produced by dinoflagellates and belong to the cyclic imine family of toxins. They are fast-acting and highly toxic when administered in vivo in rodent bioassays, causing death by respiratory depression within minutes. Studies have revealed that some cyclic imine toxins cause their toxicity by antagonizing both muscle type and heteromeric and homomeric neuronal nicotinic acetylcholine receptors (nAChRs). Pinnatoxins E, F and G all display potent toxicity in in vivo bioassays, with symptoms of toxicity similar to other cyclic imine toxins. However, very little work has been done on the mechanism of action of these pinnatoxin isomers. Thus the aim of the current study was to investigate the rank order of potency and mechanism of action of pinnatoxins E, F and G. The effects of pinnatoxin E, F and G on in vitro rat hemidiaphragm preparations were investigated using twitch tension and electrophysiological techniques to determine the effects of these toxins on cholinergic transmission at the neuromuscular junction. Pinnatoxins E, F and G all produced concentration-dependent reductions in the nerve evoked twitch response of the rat hemidiaphragm, with IC50 values ranging from 11 to 53 nM and a rank order of potency of F > G > E. Only complete washout of pinnatoxin E was evident, with pinnatoxins F and G displaying slow and incomplete washout profiles. Pinnatoxins F and G also reduced the amplitudes of spontaneous miniature endplate potentials and evoked endplate potentials at the neuromuscular junction, without affecting miniature endplate potential frequency or the resting membrane potential of the muscle fibres. These results show that pinnatoxins E, F and G are all potent neuromuscular blocking agents and cause toxicity by acting as antagonists at muscle type nicotinic acetylcholine receptors. PMID:24139849

Hellyer, Shane D; Selwood, Andrew I; Rhodes, Lesley; Kerr, D Steven

2013-12-15

165

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)

166

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

167

Molecular mechanisms that control endothelial cell contacts.  

Science.gov (United States)

Endothelial cell contacts control the permeability of the blood vessel wall. This allows the endothelium to form a barrier for solutes, macromolecules, and leukocytes between the vessel lumen and the interstitial space. Loss of this barrier function in pathophysiological situations can lead to extracellular oedema. The ability of leukocytes to enter tissue at sites of inflammation is dependent on molecular mechanisms that allow leukocytes to adhere to the endothelium and to migrate through the endothelial cell layer and the underlying basal lamina. It is a commonly accepted working hypothesis that inter-endothelial cell contacts are actively opened and closed during this process. Angiogenesis is another important process that requires well-controlled regulation of inter-endothelial cell contacts. The formation of new blood vessels by sprouting from pre-existing vessels depends on the loosening of established endothelial cell contacts and the migration of endothelial cells that form the outgrowing sprouts. This review focuses on the molecular composition of endothelial cell surface proteins and proteins of the cytoskeletal undercoat of the plasma membrane at sites of inter-endothelial cell contacts and discusses the current knowledge about the potential role of such molecules in the regulation of endothelial cell contacts. PMID:10685062

Vestweber, D

2000-02-01

168

The effect of adenosine triphosphate on vecuronium-induced neuromuscular block.  

Science.gov (United States)

Continuous IV adenosine triphosphate administration has been used during surgery in the expectation of analgesic and vasodilative effects. Because adenosine triphosphate inhibits neuromuscular transmission, we investigated whether the neuromuscular effect of vecuronium was enhanced by IV adenosine triphosphate in 29 patients randomly given either continuous IV adenosine triphosphate 0.1 mg.kg(-1).min(-1) or 0.9% NaCl when undergoing elective minor surgery. Anesthesia was induced and maintained with propofol. Neuromuscular monitoring was recorded from the adductor pollicis muscle using electromyography with train-of-four stimulation of the ulnar nerve. Vecuronium 25, 30, or 40 microg/kg was given and lag time, onset time, and maximum block were recorded. ED50 and ED95 values for each group were derived from least squares linear regression analysis. ED50 and ED95 values were 29 microg/kg and 44 microg/kg, respectively, for the adenosine triphosphate group and 26 microg/kg and 46 microg/kg, respectively, for the controls. Differences in lag time, onset time, and neuromuscular responses between the two groups were not statistically significant. A significantly larger number of patients in the adenosine triphosphate group showed hypotension (systolic blood pressure <80 mm Hg). Our results demonstrated that adenosine triphosphate 0.1 mg.kg(-1).min(-1) did not enhance the neuromuscular block induced by vecuronium. PMID:15616064

Nitahara, Keiichi; Shono, Shinjiro; Hamada, Takamitsu; Higuchi, Hideyuki; Sakuragi, Tadakazu; Higa, Kazuo

2005-01-01

169

The timing of impulse activity shapes the process of synaptic competition at the neuromuscular junction.  

Science.gov (United States)

The development of neuromuscular junctions exhibits profound remodeling that brings from an immature state characterized by multiple motoneuronal inputs per muscle fiber, to a mature mononeuronal innervation. This striking elimination process occurs both perinatally and during adult reinnervation, and is also widely present in the developing CNS. The accelerating influence of the amount of impulse activity on this process, has been shown by various studies, but a more subtle role of the time correlation of action potential firing in the competing inputs, has also been suggested. Here we explore the latter influence using a rat adult model of neuromuscular junction formation, that is reinnervation following a motor nerve crush. This shares all important features with perinatal development, especially the strict juxtaposition of the competing inputs. In fact the regenerating axons converge on a single cluster of postsynaptic receptors, that is the original endplate of each muscle fiber. This focus on the spatial aspect of competition between nerve endings was missing in our previous experiments employing a similar paradigm. We impose a chronic synchronous firing to the competing terminals, by in vivo electrical stimulation of their axons distal to a sciatic nerve conduction block. Control preparations, with similar post-crush reinnervation, are left with their natural impulse activity unperturbed. We find that the experimental muscles display a prolonged duration of polyneuronal innervation with respect to controls, indicating that hebbian mechanisms participate in the synapse elimination process. Another aspect dealt with in our study is the genuine nature of the polyneuronal innervation occurring during adult muscle reinnervation, because it is supported by both confocal microscopy and by appropriate electrophysiological tests that exclude electrical coupling of myofibers by gap junctions. PMID:20132871

Favero, M; Buffelli, M; Cangiano, A; Busetto, G

2010-05-01

170

Bloqueio neuromuscular residual após o uso de rocurônio ou cisatracúrio Bloqueo neuromuscular residual después del uso de rocuronio o cisatracúrio Residual neuromuscular block after rocuronium or cisatracurium  

Directory of Open Access Journals (Sweden)

Full Text Available JUSTIFICATIVA E OBJETIVOS: O bloqueio neuromuscular residual na sala de recuperação pós-anestésica (SRPA é um fenômeno que pode aumentar a morbidade pós-operatória, com incidência variando entre 0% e 93%. O objetivo deste estudo foi avaliar a incidência do bloqueio neuromuscular residual na SRPA. MÉTODO: Foram estudados 93 pacientes submetidos à cirurgia geral com o uso de cisatracúrio ou rocurônio. Após a admissão na SRPA foi realizada a monitorização objetiva da função neuromuscular (aceleromiografia - TOF GUARD. O bloqueio neuromuscular residual foi definido como SQE JUSTIFICATIVA Y OBJETIVOS: El bloqueo neuromuscular residual en la sala de recuperación posanestésica (SRPA es un fenómeno que puede aumentar la morbidez posoperatoria, con incidencia variando entre 0% y 93%. La finalidad de este estudio fue evaluar la incidencia del bloqueo neuromuscular residual en la SRPA. MÉTODO: Fueron estudiados 93 pacientes sometidos a cirugía general con el uso de cisatracúrio o rocuronio. Después de la admisión en la SRPA fue realizada la monitorización objetiva de la función neuromuscular (aceleromiografia - TOF-GUARD. El bloqueo neuromuscular residual fue definido como TOF BACKGROUND AND OBJECTIVES: Residual neuromuscular block in the post-anesthetic recovery unit (PACU may increase postoperative morbidity from 0% to 93%. This study aimed at evaluating the incidence of residual neuromuscular block in the PACU. METHODS: Participated in this study 93 patients submitted to general anesthesia with cisatracurium or rocuronium. After PACU admission, neuromuscular function was objectively monitored (acceleromyography - TOF GUARD. Residual neuromuscular block was defined as TOF < 0.9. RESULTS: From 93 patients, 53 received cisatracurium and 40 rocuronium. Demographics, procedure length and the use of antagonists were comparable between groups. Residual neuromuscular block was 32% in subgroup C (cisatracurium and 30% in subgroup R (rocuronium. Residual neuromuscular block was unrelated to dose, age and use of antagonists, but was related to procedure length. In subgroup C, mean procedure length was 135 minutes for patients with neuromuscular block and 161 minutes for patients without (p < 0.029. In subgroup R, mean surgery length was 122 and 150 minutes, respectively (p < 0.039. CONCLUSIONS: Both groups had high incidence of residual neuromuscular block in the PACU. Residual postoperative curarization is still a problem even with new intermediary action neuromuscular blockers. It is highly important to objectively monitor all patients submitted to general anesthesia with neuromuscular blockers.

Bruno Salomé de Morais

2005-12-01

171

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

172

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.

173

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

174

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.

175

Dynamics of nerve-muscle interaction in developing and mature neuromuscular junctions.  

Science.gov (United States)

Neuromuscular connections have long served as models of synaptic structure and function. They also provide illuminating insights into the dynamic cell-cell interactions governing synaptogenesis, neuromuscular differentiation, and the maintenance of effective function. This paper reviews recent advances in our understanding of the regulatory and inductive interactions involved in motor axon pathfinding, target recognition, bidirectional control of gene expression during synapse formation, motoneuron cell death, terminal rearrangement, and the ongoing remodeling of synaptic number, structure, and function to adjust to growth and changes in use. PMID:7480163

Grinnell, A D

1995-10-01

176

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

177

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

178

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

179

Spectrum of Cyber threats & Available Control Mechanisms  

Directory of Open Access Journals (Sweden)

Full Text Available The Internet is undoubtedly the largest public data network enabling and facilitating both personal & business communications worldwide. Wireless networking has experienced a tremendous growth becoming an integral part of homes, offices & all type of businesses. It provides many advantages, but it is also coupled with many security threats and alters the organizations overall information security risk profile. Although implementation of technological solution is the usual respond to the wireless security threats and vulnerabilities, wireless security is primarily a management issue. Cyber crime is constantly evolving and the growing increase in the number of threats that use social engineering techniques is causing concern for several businesses. All it takes is for one user to click on a malicious link and a firm’s network can be brought to a grinding halt. But the early days of cyber threats have gone now. Cyber threats have increased in large number. The volume of effect of these attacks has increased tremendously whereas the transaction time has decreased. The sources of attacks and exploitations are difficult to determine within time frames that enable victims to avoid damage, and any defensive measure is likely eventually to fail given the vulnerabilities of most cyber systems and the incapacities of users. In this paper we review different cyber threats and control mechanisms available and how these are affecting the network world.

Vikram Mangla, Dr.S.N.Panda

2013-04-01

180

MECHANISMS OF DRY SO2 CONTROL PROCESSES  

Science.gov (United States)

The report discusses physical and chemical processes and reaction mechanisms for lime spray drying and dry injection of sodium compounds in dry flue gas desulfurization (FGD) processes. It includes: chemical reactions, physical changes, proposed reaction mechanisms and mathematic...

 
 
 
 
181

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

182

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.

183

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

184

Bloqueio neuromuscular residual após o uso de rocurônio ou cisatracúrio / Residual neuromuscular block after rocuronium or cisatracurium / Bloqueo neuromuscular residual después del uso de rocuronio o cisatracúrio  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: O bloqueio neuromuscular residual na sala de recuperação pós-anestésica (SRPA) é um fenômeno que pode aumentar a morbidade pós-operatória, com incidência variando entre 0% e 93%. O objetivo deste estudo foi avaliar a incidência do bloqueio neuromuscular residual na SRPA. M [...] ÉTODO: Foram estudados 93 pacientes submetidos à cirurgia geral com o uso de cisatracúrio ou rocurônio. Após a admissão na SRPA foi realizada a monitorização objetiva da função neuromuscular (aceleromiografia - TOF GUARD). O bloqueio neuromuscular residual foi definido como SQE Abstract in spanish JUSTIFICATIVA Y OBJETIVOS: El bloqueo neuromuscular residual en la sala de recuperación posanestésica (SRPA) es un fenómeno que puede aumentar la morbidez posoperatoria, con incidencia variando entre 0% y 93%. La finalidad de este estudio fue evaluar la incidencia del bloqueo neuromuscular residual [...] en la SRPA. MÉTODO: Fueron estudiados 93 pacientes sometidos a cirugía general con el uso de cisatracúrio o rocuronio. Después de la admisión en la SRPA fue realizada la monitorización objetiva de la función neuromuscular (aceleromiografia - TOF-GUARD). El bloqueo neuromuscular residual fue definido como TOF Abstract in english BACKGROUND AND OBJECTIVES: Residual neuromuscular block in the post-anesthetic recovery unit (PACU) may increase postoperative morbidity from 0% to 93%. This study aimed at evaluating the incidence of residual neuromuscular block in the PACU. METHODS: Participated in this study 93 patients submitted [...] to general anesthesia with cisatracurium or rocuronium. After PACU admission, neuromuscular function was objectively monitored (acceleromyography - TOF GUARD). Residual neuromuscular block was defined as TOF

Bruno Salomé de, Morais; Carlos Henrique Viana de, Castro; Vera Coelho, Teixeira; Alexandre Silva, Pinto.

2005-12-01

185

Neuromuscular manifestations of viscoelastic tissue degradation following high and low risk repetitive lumbar flexion.  

Science.gov (United States)

Cumulative lumbar disorder is common in individuals engaged in long term performance of repetitive and static occupational/sports activities with the spine. The triggering source and of the disorder, the tissues involved in the failure and the biomechanical, neuromuscular, and biological processes active in the initiation and development of the disorder are not known. The hypothesis is forwarded that static and repetitive (cyclic) lumbar flexion-extension and the associated repeated stretch of the various viscoelastic tissues (ligaments, fascia, facet capsule, discs, etc.) causes micro-damage in their collagen fibers followed by an acute inflammation, triggering pain and reflexive muscle spasms/hyper-excitability. Continued exposure to activities, over time, converts the acute inflammation into a chronic one, viscoelastic tissues remodeling/degeneration, modified motor control strategy and permanent disability. Changes in lumbar stability are expected during the development of the disorder. A series of experimental data from in-vivo feline is reviewed and integrated with supporting evidence from the literature to gain a valuable insight into the multi-factorial development of the disorder. Prolonged cyclic lumbar flexion-extension at high loads, high velocities, many repetitions and short in between rest periods induced transient creep/laxity in the spine, muscle spasms and reduced stability followed, several hours later, by an acute inflammation/tissue degradation, muscular hyper-excitability and increased stability. The major findings assert that viscoelastic tissues sub-failure damage is the source and inflammation is the process which governs the mechanical and neuromuscular characteristic symptoms of the disorder. A comprehensive model of the disorder is presented. The experimental data validates the hypothesis as well as provide insights into the development of potential treatment and prevention of the disorder. PMID:22154465

Solomonow, M

2012-04-01

186

Similar increases in strength after short-term resistance training due to different neuromuscular adaptations in young and older men.  

Science.gov (United States)

Walker, S and Häkkinen, K. Similar increases in strength after short-term resistance training due to different neuromuscular adaptations in young and older men. J Strength Cond Res 28(11): 3041-3048, 2014-This study investigated whether differences in neuromuscular performance and muscle hypertrophy occur between young and older men. Twenty-three young (29 ± 9 years) and 26 older men (64 ± 8 years) completed 10 weeks of high-volume, medium load "hypertrophic" resistance training with low frequency (twice per week) with 10 young (34 ± 11 years) and 11 older men (65 ± 3 years) acting as nontraining control subjects. Training consisted of 2-5 sets of 8-14 repetitions (1- to 2-minute rest). Lower-limb dynamic (leg press) and isometric maximum leg extension force, as well as lower-limb lean mass and vastus lateralis cross-sectional area were assessed before and after the training period. Training led to significant increases in 1 repetition maximum (1RM) leg press performance in both training groups (young: 13 ± 7%, p strength between young and older men, it appears that different mechanisms underpin these improvements. PMID:25051001

Walker, Simon; Häkkinen, Keijo

2014-11-01

187

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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188

Fuzzy Adaptive Sliding Mode Control of Large Erecting Mechanism  

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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 mod...

Li Liang; Xie Jian; Huang Jian Zhao

2013-01-01

189

Neuromuscular transmission studies in human chronic Chagas' disease Estudio de la transmisión neuromuscular en la enfermedad de Chagas crónica humana  

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Full Text Available An electrophysiological investigation of the state of the neuromuscular transmission (nmt was carried out in 58 patients with the diagnosis of chronic Chagas' disease. On repetitive supramaximal nerve stimulation it was found that some patients did not show abnormalities, others had decremental muscle responses, others developed enhancement of the muscle evoked potential amplitudes, while some other patients combined both types of pathological responses. The findings suggest that some patients with chronic Chagas' disease develop impairement of nmt, though data obtained in this study do not give information about neither the type of impairement nor the localization (pre or postsynaptic, or both of the damage.Cincuenta y ocho pacientes con edades entre los 1 y 58 años, con diagnóstico de enfermedad de Chagas crónica fueron estudiados para evaluar la transmisión neuromuscular. Se estimuló en forma supramáxima el nervio cubital a nivel de muñeca, con registro de electrodos de superficie en hipotenar. Dicha estimulación se realizó a 3 Hz durante 2 segundos y 10 Hz durante 1 segundo en condiciones basales, trás 4 minutos de ejercicio mecánico, luego de 4 minutos de ejercicio mecánico mas isquemia y trás 2 minutos de liberada la isquemia. Se procedió a medir la amplitud del 3, 5, 6 y 10 potencial, que fueron expresados como variación porcentual con respecto al primero al que se le asignó un valor de 100%. Treinta pacientes no evidenciaron diferencias con respecto a la curva obtenida en 20 sujetos controles, 4 mostraron una caida del potencial evocado muscular, 6 una caida del mismo cuando el estímulo se realizó la bajas frecuencias y un incremento cuanto el estímulo fue a altas frecuencias. En los restantes 18 pacientes se observó un incremento del pem. Estos hallazgos sugieren una posible alteración de la transmisión neuromuscular en algunos pacientes que han alcanzado el estadio crónico de la enfermedad de Chagas de probable localización pré y/o post-sináptica.

Marcela Garcia Erro

1989-09-01

190

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

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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

191

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

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

C. Ortiz Leyba

2006-05-01

192

Single-cell analysis of Drosophila larval neuromuscular synapses.  

Science.gov (United States)

The neuromuscular system of Drosophila has been widely used in studies on synaptic development. In the embryo, the cellular components of this model system are well established, with uniquely identified motoneurons displaying specific connectivity with distinct muscles. Such knowledge is essential to analyzing axon guidance and synaptic matching mechanisms with single-cell resolution. In contrast, to date the cellular identities of the larval neuromuscular synapses are hardly established. It is not known whether synaptic connections seen in the embryo persist, nor is it known how individual motor endings may differentiate through the larval stages. In this study, we combine single-cell dye labeling of individual synaptic boutons and counterstaining of the entire nervous system to characterize the synaptic partners and bouton differentiation of the 30 motoneuron axons from four nerve branches (ISN, SNa, SNb, and SNd). We also show the cell body locations of 4 larval motoneurons (RP3, RP5, V, and MN13-Ib) and the types of innervation they develop. Our observations support the following: (1) Only 1 motoneuron axon of a given bouton type innervates a single muscle, while up to 4 motoneuron axons of different bouton types can innervate the same muscle. (2) The type of boutons which each motoneuron axon forms is likely influenced by cell-autonomous factors. The data offer a basis for studying the properties of synaptic differentiation, maintenance, and plasticity with a high cellular resolution. PMID:11133154

Hoang, B; Chiba, A

2001-01-01

193

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

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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

194

Coherent, mechanical control of a single electronic spin.  

Science.gov (United States)

We demonstrate coherent quantum control of a single spin driven by the motion of a mechanical resonator. The motion of a mechanical resonator is magnetically coupled to the electronic spin of a single nitrogen-vacancy center in diamond. Synchronization of spin-addressing protocols to the motion of the driven oscillator is used to fully exploit the coherence of this hybrid mechanical-spin system. We demonstrate applications of this coherent mechanical spin-control technique to nanoscale scanning magnetometry. PMID:22800099

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

2012-08-01

195

Mechanical Backup For Fly-By-Wire Control System  

Science.gov (United States)

Mechanical device eliminates need for redundant fly-by-wire subsystems. Main components are two linkages. One connected to control column in conventional, reversible control system. Other slides inside first linkage and connected to pilot's control wheel. In addition to aircraft applications, design used in control systems in which computer control desirable but safety backup systems required; for example, in boat rudders, engine controls in boats and automobiles, and controls in construction equipment.

Stewart, Eric C.

1992-01-01

196

[Classical dengue transmission dynamics involving mechanical control and prophylaxis].  

Science.gov (United States)

Dengue fever transmission dynamics were studied in an endemic region considering the use of preventative measures and mechanical control in reducing transmission of the disease. A system of ordinary differential equations was proposed, describing the dynamics and their evolution as determined by numerical simulation. Different mechanical control and prophylaxis strategies were compared to the situation without control. The basic reproduction number R? was determined R? to show that if R? > 1 there would be a risk of an epidemic and otherwise the disease would have low impact levels. The basic reproduction number helps determine the dynamics' future pattern and contrast the results so obtained with those obtained numerically. It was concluded that although prophylaxis and mechanical control alone provide effective results in controlling the disease, if both controls are combined then infection levels become significantly reduced. Around 60 % mechanical control and prevention levels are needed to provide suitable results in controlling dengue outbreaks. PMID:22030689

Toro-Zapata, Hernán D; Restrepo, Leonardo D; Vergaño-Salazar, Juan G; Muñoz-Loaiza, Aníbal

2010-12-01

197

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

198

Neuromuscular dynamic restraint in women with anterior cruciate ligament injuries.  

Science.gov (United States)

The purpose of this study was to identify neuromuscular characteristics related to dynamic restraint in the knee. Observing compensatory changes to these characteristics in women with anterior cruciate ligament injuries provides important information for understanding functional knee stability, injury prevention, and performance. Twelve female subjects with anterior cruciate ligament injuries and 17 female control subjects participated in this study to assess electromyographic activity during landing from a hop and knee perturbation; hamstring muscle stiffness and flexibility; and isokinetic strength. Females with anterior cruciate ligament deficiencies had significantly increased preparatory muscle activity in the lateral hamstring before landing, but no differences in reactive muscle activity during landing or reflex latency after joint perturbation. Females with anterior cruciate ligament deficiencies had significantly less hamstring muscle stiffness and flexibility, but also had greater peak torque and torque development for knee flexion. Lower Lysholm scores were observed in females with anterior cruciate ligament deficiencies but no difference was found in functional performance of the single leg hop test. These neuromuscular characteristics provide a foundation for future research investigating injury prevention and rehabilitation techniques that maximize dynamic restraint through stiffness regulation and the timing of specific muscle activation strategies. PMID:15292807

Swanik, Charles Buz; Lephart, Scott M; Swanik, Kathleen A; Stone, David A; Fu, Freddie H

2004-08-01

199

Uso de sugamadex após reversão incompleta com neostigmine do bloqueio neuromuscular induzido por rocurônio Uso de sugamadex después de la reversión incompleta con neostigmine del bloqueo neuromuscular inducido por rocuronio Use of sugammadex after neostigmine incomplete reversal of rocuronium-induced neuromuscular blockade  

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Full Text Available JUSTIFICATIVA E OBJETIVOS: O uso de bloqueadores neuromusculares (BNM na prática anestésica já tem mais de meio século e sempre foi um desafio para os anestesiologistas. Até bem pouco tempo a reversão dos bloqueadores neuromusculares adespolarizantes só possuia uma opção: a utilização de anticolinesterásicos. No entanto em algumas situações como na presença de bloqueio neuromuscular profundo após o uso de altas doses do relaxante, o uso de anticolinesterásicos não possibilita a adequada reversão do bloqueio neuromuscular. Recentemente uma ciclodextrina gama mostrou-se altamente eficaz para a reversão do BNM de agentes esteroidais, o sugamadex. RELATO DO CASO: Paciente do sexo feminino, submetida à laparotomia exploradora de emergência após intubação em sequência rápida com uso de rocurônio 1,2 mg.kg-1. Ao final da cirurgia a paciente foi descurarizada com neostigmina, no entanto a monitoração da junção neuromuscular não apresentou a recuperação esperada, revelando curarização residual. Foi utilizado sugamadex 2 mg.kg-1 e a paciente apresenta reversão completa do BNM em apenas 2 minutos. CONCLUSÃO: A adequada recuperação do bloqueio neuromuscular residual é necessária para o pleno controle das funções da faringe e respiratória, evitando assim complicações. A adequada recuperação só pode ser obtida através da monitoração da junção neuromuscular com uma relação de TOF acima de 0,9. Muitas vezes a reversão do BNM com o uso de anticolinesterásicos pode não reverter completamente o BNM, no entanto na ausência da monitoração objetiva este diagnóstico não é possível. O caso ilustra o diagnóstico de BNM residual mesmo após a reversão com anticolinesterásicos, resolvido com a administração de sugamadex, uma alternativa segura para a reversão dos BNM adespolarizantes esteroidais.JUSTIFICATIVA Y OBJETIVOS: El uso de bloqueantes neuromusculares (BNM en la práctica anestésica cuenta ya con más de medio y siempre fue un reto para los anestesiólogos. Hasta hace poco tiempo la reversión de los bloqueantes neuromusculares adespolarizantes solo tenía una opción: la utilización de antocolinesterásicos. Sin embargo, en algunas situaciones como en presencia de bloqueo neuromuscular profundo después del uso de altas dosis del relajante, el uso de anticolinesterásicos no posibilita la adecuada reversión del bloqueo neuromuscular. Recientemente una ciclodextrina gama mostró ser altamente eficaz para la reversión del BNM de agentes esteroidales, como el sugamadex. RELATO DE CASO: Paciente del sexo femenino, sometida a la laparotomía exploradora de emergencia después de la intubación en secuencia rápida con el uso de rocuronio 1,2 mg.kg-1. Al término de la operación, la paciente fue descurarizada con neostigmina, pero la monitorización de la junción neuromuscular no presentó la recuperación esperada, revelando la curarización residual. Fue utilizado sugamadex 2 mg.kg-1 y comprobamos que la paciente presenta una reversión completa del BNM en solamente 2 minutos. CONCLUSIONES: La correcta recuperación del bloqueo neuromuscular residual es necesaria para el pleno control de las funciones de la faringe y respiratoria, evitando así complicaciones. La adecuada recuperación solo puede obtenerse por medio de la monitorización de la junción neuromuscular con una relación de TOF por encima de 0,9. En muchas ocasiones, la reversión del BNM con el uso de anticolinesterásicos puede no revertir completamente el BNM, pero sin embargo en ausencia de la monitorización objetiva, ese diagnóstico no puede ser alcanzado. El caso ilustra el diagnóstico de BNM residual incluso después de la reversión con anticolinesterásicos, resuelto con la administración de sugamadex, una alternativa segura para la reversión de los BNM adespolarizantes esteroidales.BACKGROUND AND OBJECTIVES: Neuromuscular blockers (NMB have been used for more than half of a century in anesthesia and have always been a challenge for anesthesiologists. Until recently,

Cássio Campelo de Menezes

2012-08-01

200

STRATEGIC CONTROLLING MECHANISM AND MANAGEMENT COMPETITIVENESS OF THE ENTERPRISE  

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Full Text Available In the paper author studies the specifics of using the strategic controlling mechanism during management competitiveness of the enterprise. Highlighted methods of strategic management, among which occupies a special place of strategic controlling mechanism as the most progressive. Justified using term mechanism in the concept of strategic controlling. Developed concise and objective concept of strategic controlling mechanism - a comprehensive, autonomous, self-organizing system of information-analytical support of the top-management of the enterprise in the implementation of strategic management, consisting of the elements controlling operating interdependently in a formalized sequence.In this article author describes the results of work on the synthesis of two concepts: strategic controlling and competitiveness. Proposed and justified their interaction. He describes the basic tools and principles of strategic controlling their interactions in the system of management of competitiveness.

Pavel Leonidovich Vasilev

2014-08-01

 
 
 
 
201

Acrylamide Administration Induces Neuromuscular Junction Degeneration  

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Acrylamide, a widely used vinyl monomer, is known to induce central-peripheral axonopathy. In the present study, investigate the effect of acrylamide (ACR) on the neuromuscular junctions of the Swiss albino mice. Animals were given acrylamide (10 and 20mg Kg?1) interapertioneally 6 days weekly for 4 weeks. Intoxication with ACR at the high dose results in the prominent neurological signs and a clinical illness characterized by weakness and ataxia of the limbs. Pathological eviden...

Abdelmeguid, Nabila E.; Essawy, Amina E.; Abdelreheem, Yasser I.

2002-01-01

202

Synaptic Defects in the Spinal and Neuromuscular Circuitry in a Mouse Model of Spinal Muscular Atrophy  

Science.gov (United States)

Spinal muscular atrophy (SMA) is a major genetic cause of death in childhood characterized by marked muscle weakness. To investigate mechanisms underlying motor impairment in SMA, we examined the spinal and neuromuscular circuitry governing hindlimb ambulatory behavior in SMA model mice (SMN?7). In the neuromuscular circuitry, we found that nearly all neuromuscular junctions (NMJs) in hindlimb muscles of SMN?7 mice remained fully innervated at the disease end stage and were capable of eliciting muscle contraction, despite a modest reduction in quantal content. In the spinal circuitry, we observed a ?28% loss of synapses onto spinal motoneurons in the lateral column of lumbar segments 3–5, and a significant reduction in proprioceptive sensory neurons, which may contribute to the 50% reduction in vesicular glutamate transporter 1(VGLUT1)-positive synapses onto SMN?7 motoneurons. In addition, there was an increase in the association of activated microglia with SMN?7 motoneurons. Together, our results present a novel concept that synaptic defects occur at multiple levels of the spinal and neuromuscular circuitry in SMN?7 mice, and that proprioceptive spinal synapses could be a potential target for SMA therapy. PMID:21085654

Zingg, Brian; Feng, Zhihua; Ko, Chien-Ping

2010-01-01

203

[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

204

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.

205

Neuromuscular scoliosis - surgical management and outcomes  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english Neuromuscular scoliosis affects a heterogeneous group of patients with myopathic, upper and lower motor neuron diseases. Spinal surgery is often required to optimise respiratory, sitting and ambulatory function. OBJECTIVES: Review of management and outcomes of surgically treated neuromuscular scolio [...] sis. STUDY DESIGN: Retrospective review of prospectively maintained data, including demographics, intra-operative variables, pre- and post-operative imaging, complications, outcomes and a telephonic follow-up questionnaire. RESULTS: Ninety-eight patients (45 male and 53 female) were included in the study. The average operating time was 230 (100-525 ± 60.9) minutes and an average of 15.4 (8-19 ± 2.9) levels were fused. Pedicle screw only constructs corrected the primary curve by 63% initially and 56% correction at last follow-up. Hybrid constructs had an immediate correction of 69% and 47% at last follow-up. Although pedicle screw constructs lost less correction when compared to hybrid constructs, this was not a statistically significant difference. Pelvic obliquity was corrected from 14.02 (0-80 ± 15.54) to 4.06 (0-35 ± 7.69) degrees. The majority of the telephonic responses were positive. CONCLUSION: : Corrective spinal surgery in the neuromuscular patient is demanding with a high rate of complications but outcomes are good, with radiographic correction maintained in the long term and high level of patient and parent satisfaction. LEVEL OF EVIDENCE: III

A, Puddu; RN, Dunn.

206

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

207

Noninvasive measurement of the tension-time index in children with neuromuscular disease.  

Science.gov (United States)

Respiratory muscle weakness is common in children with neuromuscular disease (NMD). We hypothesized that weakness puts them at risk for respiratory muscle fatigue, a harbinger of chronic respiratory failure. We therefore measured a noninvasive index of respiratory muscle fatigue, the tension-time index of the respiratory muscles (TT(mus)), in 11 children with NMD and 13 control subjects. Spirometric flow rates and maximal inspiratory pressure were significantly lower in the NMD group than in controls (43 +/- 23 vs. 99 +/- 21 cmH2O, P TT(mus) was significantly higher in the NMD group than in controls (0.205 +/- 0.117 vs. 0.054 +/- 0.021, P TT(mus) was primarily due to an increase in the ratio of average mean inspiratory pressure to maximal inspiratory pressure, indicating decreased respiratory muscle strength reserve. We found a significant correlation between TT(mus) and the residual volume-to-total lung capacity ratio (r = 0.504, P = 0.03) and a negative correlation between TT(mus) and forced expiratory volume in 1 s (r = -0.704, P fatigue. TT(mus) may be useful in assessing tolerance during weaning from mechanical ventilation, identifying impending respiratory failure, and aiding in the decision to institute therapies. PMID:12909595

Mulreany, Laura T; Weiner, Daniel J; McDonough, Joseph M; Panitch, Howard B; Allen, Julian L

2003-09-01

208

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

Science.gov (United States)

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

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

2009-10-01

209

Molecular motors: design, mechanism and control  

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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 thermodyn...

Chowdhury, Debashish

2007-01-01

210

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

1995-07-01

211

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

212

The development of ultrashort acting neuromuscular relaxant tropane derivatives.  

Science.gov (United States)

There is a need for neuromuscular relaxant (NMR) agents that are of the "nondepolarizing type" and produce rapidly developing and short-lasting skeletal muscle relaxation in anesthesiology. Many efforts have been directed to produce such agents. Our research focused on the design, synthesis, and evaluation of numerous "bisquaternary" derivatives of the cyclic aminoalkanes: tropane and granatane. Through systematic "steric structure-activity relationship" studies, we arrived at some new bisquaternary tropine and granatanol diesters, which in laboratory studies appeared to be the fastest and shortest acting NMRs recognized so far. Their ultrashort duration action-mechanism was, however, linked to the formation of nephrotoxic metabolites, precluding further development. Even so, we believe that the scientific information gained from more than a thousand such agents, will be useful toward developing the "ideal," ultrashort-acting NMR that could be clinically successful without the use of "reversing" agents, at least until "new biotechnology" may solve all problematic aspects of "transient" muscle relaxation. PMID:19272540

Gyermek, Laszlo; Lee, Chingmuh

2009-03-01

213

[Effect of berberine, glaucine, stephaglabrine and sanguiritrine on neuromuscular transmission].  

Science.gov (United States)

Natural alkaloid drugs, glaucine, stephaglabrine and sanguiritrine, are shown to affect the synaptic transmission in a fairly complicated manner and seem to involve several different mechanisms of action. These substances as well as berberine reduce amplitude of the spontaneous miniature end plate potentials in a frog neuromuscular junction. At low concentrations all the mentioned alkaloids diminish frequency of miniature potentials, but increase it when their concentration exceeds a certain value. Sanguiritrine is the most active in this respect (nearly a 100-fold increase), that is probably associated with its uncoupling effect on the mitochondrial oxidative phosphorylation. Sanguiritrine and stephaglabrine both cause repeated muscle contractions, that is in line with their anti-cholinesterase properties. Glaucine provokes only muscle contracture if present at relatively high concentration. PMID:1652103

Bitkov, V V; Khashaev, Kh -M; Pronevich, L A; Nenashev, V A; Batrakov, S G

1991-01-01

214

Installing and detaching apparatus for a control rod drive mechanism  

International Nuclear Information System (INIS)

Object: To facilitate maintenance and repair of a control rod drive mechanism. Structure: The apparatus comprises a means moving in a moving direction of a control rod within a reactor vessel, said moving means having a housing mounted thereon, a means mounted on the reactor vessel to release a connection between a control rod drive mechanism connected to the control rod and the control rod, and a means for mounting and removing a fixing means which connects the reactor vessel to the control rod drive means. With this arrangement, cooling water of high radioactivity level may not be leaked outside to thereby notably reduce dangerousness of exposure and materially cut time required for mounting and removing the control rod drive mechanism. (Ohara, T.)

215

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)

216

Characterization of the mechanisms controlling Greatwall activity.  

Science.gov (United States)

Here we investigate the mechanisms regulating Greatwall (Gwl), a serine/threonine kinase essential for promoting the correct timing of mitosis. We identify Gwl as a unique AGC kinase that, unlike most AGC members, appears to be devoid of a hydrophobic motif despite the presence of a functional hydrophobic pocket. Our results suggest that Gwl activation could be mediated by the binding of its hydrophobic pocket to the hydrophobic motif of another AGC kinase. Our molecular modeling and mutagenic analysis also indicate that Gwl displays a conserved tail/linker site whose phosphorylation mediates kinase activation by promoting the interaction of this phosphorylated residue with two lysines at the N terminus. This interaction could stabilize the ?C-helix and maintain kinase activity. Finally, the different phosphorylation sites on Gwl are identified, and the role of each one in the regulation of Gwl kinase activity is determined. Our data suggest that only the phosphorylation of the tail/linker site, located outside the putative T loop, appears to be essential for Gwl activation. In summary, our results identify Gwl as a member of the AGC family of kinases that appears to be regulated by unique mechanisms and that differs from the other members of this family. PMID:21444715

Vigneron, Suzanne; Gharbi-Ayachi, Aicha; Raymond, Anne-Aurélie; Burgess, Andrew; Labbé, Jean-Claude; Labesse, Gilles; Monsarrat, Bernard; Lorca, Thierry; Castro, Anna

2011-06-01

217

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

218

EFFECTIVENESS OF NEUROMUSCULAR TRAINING FOR BASKET BALL PLAYERS ON PERFORMANCE OF STAR EXCURSION BALANCE TEST  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background and introduction:To determine the effect of neuromuscular training program (NMTP) focused oncore stability and lower extremity strength on performance of star excursion balance test (SEBT) inbasketballplayers.Method:: Pre to post test experimental study design randomisedthirty Basketball players each 15 into NMTPand control group. Players trained together as a team in which NMTP group participated 4 weeks of NMTPtwice a week and Control group followed their regular protocol as guid...

Bhargava Kumar Bhaskar; Vinod Babu. K *; Sai Kumar. N; Vikas Kadam V

2013-01-01

219

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

Directory of Open Access Journals (Sweden)

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

Smyth Neil

2008-09-01

220

Control Mechanism and Security Region for Intentional Islanding Transition  

DEFF Research Database (Denmark)

This paper investigates the control mechanism for intentional islanding transition, when a Low Voltage (LV) or Medium Voltage (MV) distribution system, which is usually under grid connection mode, is supposed to be separated from the upstream grid, due to either maintenance or a disturbance in the grid. The concept of Islanding Security Region (ISR) has been proposed as an organic composition of the developed control mechanism. The purpose of this control mechanism is to maintain the frequency stability and eventually the security of power supply to the customers, by utilizing resources from generation and demand sides. The control mechanism can be extended to consider the distributed generations like wind power and other innovative technologies such as the Demand as Frequency controlled Reserve (DFR) technique in the future.

Chen, Yu; Xu, Zhao

2009-01-01

 
 
 
 
221

An immunosurveillance mechanism controls cancer cell ploidy.  

Science.gov (United States)

Cancer cells accommodate multiple genetic and epigenetic alterations that initially activate intrinsic (cell-autonomous) and extrinsic (immune-mediated) oncosuppressive mechanisms. Only once these barriers to oncogenesis have been overcome can malignant growth proceed unrestrained. Tetraploidization can contribute to oncogenesis because hyperploid cells are genomically unstable. We report that hyperploid cancer cells become immunogenic because of a constitutive endoplasmic reticulum stress response resulting in the aberrant cell surface exposure of calreticulin. Hyperploid, calreticulin-exposing cancer cells readily proliferated in immunodeficient mice and conserved their increased DNA content. In contrast, hyperploid cells injected into immunocompetent mice generated tumors only after a delay, and such tumors exhibited reduced DNA content, endoplasmic reticulum stress, and calreticulin exposure. Our results unveil an immunosurveillance system that imposes immunoselection against hyperploidy in carcinogen- and oncogene-induced cancers. PMID:23019653

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

2012-09-28

222

Mechanical systems a unified approach to vibrations and controls  

CERN Document Server

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

Gans, Roger F

2015-01-01

223

Gate-controlled shutter mechanism for DEPFETs  

International Nuclear Information System (INIS)

DEPFET pixel detectors offer excellent signal to noise ratio, resolution and low power consumption with few material. They will be used in Belle 2. In addition, it is a candidate for the ILC. Due to the rolling shutter read-out they have integration times in the order of several tens of microseconds which can create problems in applications with temporary high background, for instance during the injection of noisy bunches. In order to overcome this we study a new operation mode which allows a gated or shutter controlled operation of the detector. This makes the detector blind for a certain time interval in which noise is expected whereas the charge of the previous signal will not be removed. Simulations and first measurements are presented.

224

Gate-controlled shutter mechanism for DEPFETs  

Energy Technology Data Exchange (ETDEWEB)

DEPFET pixel detectors offer excellent signal to noise ratio, resolution and low power consumption with few material. They will be used in Belle 2. In addition, it is a candidate for the ILC. Due to the rolling shutter read-out they have integration times in the order of several tens of microseconds which can create problems in applications with temporary high background, for instance during the injection of noisy bunches. In order to overcome this we study a new operation mode which allows a gated or shutter controlled operation of the detector. This makes the detector blind for a certain time interval in which noise is expected whereas the charge of the previous signal will not be removed. Simulations and first measurements are presented.

Mueller, Felix; Koffmane, Christian; Moser, Hans-Guenther; Ninkovic, Jelena; Richter, Rainer; Andricek, Ladislav; Wassatsch, Andreas [Max-Planck-Institut fuer Physik, Muenchen (Germany)

2012-07-01

225

Mechanisms controlling radionuclide mobility in forest soils  

International Nuclear Information System (INIS)

Soil processes strongly influence the radionuclide mobility in soils. The mobility of radionuclides in forest soils is governed by several processes involving both abiotic and biotic factors. The sorption-desorption process chiefly governs the activity of radionuclides in the soil solution, hence thereby their mobility and biological availability. Radiocaesium exhibits a very low mobility in mineral soils. Both mobility and bioavailability however increase as the thickness of organic layers and their content in organic matter increases. Clay minerals of micaceous origin strongly act as slinks for radiocaesium in forest soils. The magnitude of cesium mineral fixation in topsoils is expected to be the highest in mineral soils of Eutric cambisol type, and, to a lesser extent, of type of Distric cambisol and Podzoluvisol. A low mobility of radiocaesium in the surface horizons of forest soils may also be partially explained by a biological mobilization: fungi absorb radiocaesium and transport it to upper layers, thereby contributing to constantly recycle the radioelement in the organic horizons. This mechanism is probably important in soils with thick organic layers (Podsol, Histosol, and, to a lesser extent, Distric cambisol and Podzoluvisol). Radionuclides can be associated with soluble organic anions in the soil solution of forest acid soils. Such associations are highly mobile: they are stable in conditions of poor biological activity (low temperatures, acid soil infertility, water excess, etc.). Their magnitude is expected to be the highest in thick acid organic layers (soils of type Podzol and Histosol)

226

Neuromuscular and hormonal adaptations to resistance training : special effects of time of day of training  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The majority of the processes in human physiology and behaviour exhibit daily variation. Neuromuscular performance has been repeatedly shown to be lower in the morning hours compared to the rest of the day. However, the scientific data available provide somewhat conflicting results on the origin and mechanisms of diurnal variation in maximum strength and power. In addition, very limited scientific evidence exists as to whether this diurnal variation can be diminished by time-of-day-specific r...

Sedliak, Milan

2009-01-01

227

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

228

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.)

229

Partial neuromuscular blockade in humans enhances muscle blood flow during exercise independently of muscle oxygen uptake and acetylcholine receptor blockade  

DEFF Research Database (Denmark)

This study examined the role of acetylcholine for skeletal muscle blood flow during exercise by use of the competitive neuromuscular blocking agent cisatracurium in combination with the acetylcholine receptor blocker glycopyrrone. Nine healthy male subjects performed a 10-min bout of one-legged knee-extensor exercise (18W) during control conditions and with cisatracurium blockade, as well as with cisatracurium blockade with prior glycopyrrone infusion. Thigh blood flow and vascular conductance in control and with cisatracurium infusion were similar at rest and during passive movement of the leg, but higher (p<0.05) during exercise with cisatracurium than in control (3.83+/-0.42 vs. 2.78+/-0.21 L min(-1) and 26.9+/-3.4 vs. 21.8+/-2.0 ml min(-1) mmHg(-1) at the end of exercise). Thigh oxygen uptake was similar in control and with cisatracurium infusion both at rest and during exercise, being 354+/-33 and 406+/-34 ml min(-1), at the end of exercise. Combined infusion of cisatracurium and glycopyrron caused a similar increase in blood flow as cisatracurium infusion alone. The current results demonstrate that neuromuscular blockade leads to enhanced thigh blood flow and vascular conductance during exercise, events that are not associated with either acetylcholine or an increased oxygen demand. The results do not support an essential role for acetylcholine, released form the neuromuscular junction, in exercise hyperaemia or for the enhanced blood flow during neuromuscular blockade. The enhanced exercise hyperemia during partial neuromuscular blockade may be related to a greater recruitment of fast-twitch muscle fibres. Key words: blood flow, neuromuscular blockade, exercise, skeletal muscle.

Hellsten, Ylva; Krustrup, Peter

2009-01-01

230

Neuromuscular adaptations during submaximal prolonged cycling.  

Science.gov (United States)

This study aims at evaluating the neuromuscular adaptations occurring during submaximal prolonged cycling tasks. In particular, we want to assess changes in surface electromyographic (sEMG) signal recorded during a pedaling task, performed by six subjects on a cycle-simulator at a constant power output, until voluntary exhaustion. Task failure was defined as the instant the subject was no longer able to maintain the required task. Electromyographic activity was recorded from eight muscles of the dominant leg and burst characteristics of sEMG signals were analyzed in order to assess the changes in muscle activity level produced by the occurrence of neuromuscular fatigue. In particular, three features were extracted from the sEMG signal for each burst: amplitude, location of the maxima and mean profile of the burst envelope. We have reported an increase in the amplitude parameter for all subjects only for Vastii while bi-articular muscles presented a high variability among subjects. Also the location of the maximal values of the mean envelope of the bursts was found to change when considering bi-articular or mono-articular muscles. The envelope profile was found not to be subject to alterations when comparing the end of the task with the beginning. We speculated that neuromuscular fatigue induces changes essentially in the mono-articular muscles which produce power. This phenomenon is highly correlated with the adopted pedaling strategy which, being not constrained, induces subjects to express the maximal power in the downstroke phase, related to knee extension and involving mainly mono-articular muscles. PMID:23366709

Castronovo, A M; De Marchis, C; Bibbo, D; Conforto, S; Schmid, M; D'Alessio, T

2012-01-01

231

Mechanisms of using mutations in pest control  

International Nuclear Information System (INIS)

Traditional chemically based methods for insect control have been shown to have serious limitations, and many alternative approaches have been developed and evaluated, including those based on the use of different types of mutation. The mutagenic action of ionizing radiation was well known in the field of genetics long before it was realized by entomologists that it might be used to induce dominant lethal mutations in insects, which, when released, could sterilize wild female insects. The use of radiation to induce dominant lethal mutations in the sterile insect technique is now a major component of many large and successful programs for pest suppression and eradication. Specific types of mutations can also be used to make improvements to the sterile insect technique, especially for the development of strains for the production of only male insects for sterilization and release. These strains utilize male translocations and a variety of selectable mutations, either conditional or visible, so that at some stages of development, the males can be separated from the females. (author)

232

Predictive congestion control mechanism for MANET  

Directory of Open Access Journals (Sweden)

Full Text Available In adhoc networks connection failure between source and destination often occurs, due to mobility of nodes. After every failure the connection between source and destination gets disconnected.The problem is while sending data packets from source to destination, there is a possibility of occurring congestion at any node incurring high packet loss and long delay, which cause the performance degradation of a network. This paper presents predictive congestion control routing protocol for wireless Ad-hoc networks called as PCCAODV. Unlike traditional AODV, predictive congestion index of a node as the ratio of current queue occupancy over total queue size at node level. Based on a congestion index, PCCAODV utilizes the upstream nodes and down stream nodes of a congested node and initiates route finding process Bi-directionally to find alternate noncongested path between them for transmitting data. Suppose that the process find more non congested multipaths and decides a finest single path for transmitting data. The protocol is implemented and simulated using Ns-2 simulator. Performance comparisons of the proposed PCCAODV protocol against AODV is presented and shown that the proposed algorithm performs well.

S. Subburam

2012-11-01

233

Cyclic movement pin mechanism for controlling a nuclear reactor  

International Nuclear Information System (INIS)

This invention concerns a recurring movement pin mechanism for controlling a nuclear reactor by shifting a neutron absorbing assembly, vertically mobile in the nuclear reactor, to adjust the power and for emergency shut-down. This mechanism ensures a continuous movement and accurate shut-down at any level of the travel height of the absorbing assembly in the core. It also prevents the impacts of the pivoting pins in the control rod slots

234

?????????????????? Brown Adipsoe Tissue Differentiation and Control Mechanism  

Directory of Open Access Journals (Sweden)

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

235

Eye mechanics and their implications for eye movement control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The topic of this thesis is the investigation of the mechanical properties of the oculomotor system and the implications of these properties for eye movement control. The investigation was conducted by means of computer models and simulations. This allowed us to combine data from anatomy, physiology and psychophysics with basic principles of physics (mechanics) and mathematics (geometry). In chapter 2 we investigate the degree to which mechanical and neural non-linearities contribute to t...

Koene, Ansgar Roald

2002-01-01

236

Stabilizability and Motion Tracking Conditions for Mechanical Nonholonomic Control Systems  

Directory of Open Access Journals (Sweden)

Full Text Available This paper addresses formulation of stabilizability and motion tracking conditions for mechanical systems from the point of view of constraints put on them. We present a new classification of constraints, which includes nonholonomic constraints that arise in both mechanics and control. Based on our classification we develop kinematic and dynamic control models of systems subjected to these constraints. We demonstrate that a property of being a “hard-to-control” nonholonomic system may not be related to the nature of the constraints. It may result from the formulation of control objectives for a system. We examine two control objectives which are stabilization to the target equilibrium by a continuous static state feedback control and motion tracking. Theory is illustrated with examples of control objective formulations for systems with constraints of various types.

El?bieta Jarz?bowska

2007-06-01

237

Mechanics and model-based control of advanced engineering systems  

CERN Document Server

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

Irschik, Hans; Krommer, Michael

2014-01-01

238

Iterative Learning Control of a Flexible Mechanical System Using Accelerometers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Control of a flexible mechanical system using Iterative Learning Control (ILC) is studied using a linear two-mass model. The available signals are position of the first mass and acceleration of the second mass. An ILC algorithm using an estimate of the position of the second mass is evaluated in simulations showing promising properties.

Gunnarsson, Svante; Norrlo?f, Mikael

2000-01-01

239

System defense mechanisms in nuclear power generation control computers  

International Nuclear Information System (INIS)

Dual-redundant computers are used to control and monitor the production of power from Ontario Hydro's nuclear power reactors. Each computer must have the capability of monitoring its own performance and detecting faults. Upon fault detection, each computer must initiate corrective responses to ensure the integrity of critical control functions. This paper reviews those features the authors have termed system defense mechanisms

240

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

 
 
 
 
241

Research on Internal Flow Control Mechanism of For CES Routers  

Directory of Open Access Journals (Sweden)

Full Text Available To improve the communication efficiency and security between Control Elements (CEs and Forwarding Elements (FEs of For CES routers, this study researches on internal flow control mechanism. Firstly, an evaluation model based on communication of Transport Mapping Layer (TML is proposed, which is used to improve service performance of TML. Secondly, in order to prevent redirect channel interference with control channel, this study proposes a bandwidth allocation algorithm called Dynamic Probabilistic Priority Based on Rate and Buffer (DPPBRB. Lastly, to avoid the potential congestion on control channel between one CE and multiple FEs, this study puts forward an internal flow control mechanism. These internal flow control methods that this study proposed effectively prevents the DoS attack from redirect messages and improves reliability of For CES routers. Simulation and experiment results show the feasibility and effectiveness of these methods.

Bin Zhuge

2011-01-01

242

Monolithic Controlled Delivery Systems: Part I. Basic Characteristics and Mechanisms  

Directory of Open Access Journals (Sweden)

Full Text Available The article considers contemporary systems for controlled delivery of active agents, such as drugs, agricultural chemicals, pollutants and additives in the environment. A useful classification of the available controlled release systems (CRS is proposed according to the type of control (passive, active or self-preprogrammed and according to the main controlling mechanism (diffusion, swelling, dissolution or erosion. Special attention is given to some of the most used CRS - polymer monoliths. The structural and physical-chemical characteristics of CRS as well as the basic approaches to their production are examined. The basic mechanisms of controlled agent release are reviewed in detail and factors influencing the release kinetics are classified according to their importance. The present study can be helpful for understanding and applying the available mathematical models and for developing more comprehensive ones intended for design of new controlled delivery systems.

Rumiana Blagoeva

2006-04-01

243

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

244

A control-rod actuating mechanism for nuclear reactors  

International Nuclear Information System (INIS)

The invention relates to a control-rod actuating mechanism for nuclear reactors, designed for handling a transfer rod to which is fastened a control-rod. The mechanism compises magnetically actuated hooks for moving a transfer-rod, and a electrically actuated means for locking said hook at its locking position on the transfer-rod, said electrically actuated means being maintained in its position whenever the electric current feeding same is cut-off. This can be applied to nuclear reactors for keeping the control-rods out of the core whenever the reactor-vessel is opened

245

Neural factors regulate AChR subunit mRNAs at rat neuromuscular synapses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To elucidate the nature of signals that control the level and spatial distribution of mRNAs encoding acetylcholine receptor (AChR), alpha-, beta-, gamma-, delta- and epsilon-subunits in muscle fibers chronic paralysis was induced in rat leg muscles either by surgical denervation or by different neurotoxins that cause disuse of the muscle or selectively block neuromuscular transmission pre- or postsynaptically and cause an increase of AChRs in muscle membrane. After paralysis, the levels and t...

1991-01-01

246

Assessment of ventilatory neuromuscular drive in patients with obstructive sleep apnea  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 pa...

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

1998-01-01

247

Physiologic neuromuscular dental paradigm for the diagnosis and treatment of temporomandibular disorders.  

Science.gov (United States)

Shifting from traditional anatomical/mechanistic models, the physiologic neuromuscular dentistry (PNMD) paradigm acknowledges the primacy of physiology in shaping and controlling anatomy in a functioning human body. Occlusal disharmony from mandibular discrepancy to cranium leads to temporomandibular disorders (TMD), which is a disease of musculoskeletal imbalance in the postural chain exceeding the individual's physiologic adaptive capacity. To diagnose optimal craniomandibular alignment, PNMD is guided by real-time objective physiologic data such as electromyography (EMG). PMID:25174214

Raman, Prabu

2014-08-01

248

Inherited neuromuscular diseases in the mouse: a review of the literature / Doenças neuromusculares hereditárias em camundongos: revisão da literatura  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Existem inúmeras doenças neuromusculares que acometem seres humanos. A grande maioria delas é insuficientemente conhecida quanto a mecanismos fisiopatológicos e tratamentos adequados. A limitação na manipulação experimental em «anima nobili» faz-nos procurar meios alternativos para o estudo dessas d [...] oenças, tais como animais experimentais com distúrbios neuromusculares geneticamente transmitidos. Estes mutantes constituem fonte inesgotável e valiosa de informações quanto a mecanismos fisiopatogênicos e processos patológicos básicos em doenças neuromusculares. Entre as diversas espécies animais afetadas por distúrbios neuromusculares o camundongo é de particular interesse devido ao seu baixo custo de manutenção, rápida reprodutividade e pequeno tamanho, o que permite amplos estudos morfológicos a custos acessíveis. Nesta revisão analisamos 20 camundongos mutantes com distúrbios afetando nervo periférico, músculo esquelético ou junção neuromuscular. Aspectos genéticos, clínicos e patológicos são discutidos na intenção de oferecer informação atualizada sobre essas mutações animais, muitas das quais de. grande interesse como modelos experimentais de doenças neuromusculares humanas. Abstract in english There are several neuromuscular disorders affecting the human being. Most of these are poorly understood and lack an effective treatment. Due to the limitation of experimental manipulation in «anima nobili», inherited neuromuscular diseases in laboratory animals constitute a valuable source of scien [...] tific information. Amongst several animal species affected by neuromuscular disorders the house mouse is of particular interest because of its small size, short pregnancy and low costs of maintanence. In the present review 20 murine mutants with diseases affecting peripheral nerves, skeletal muscles and motor end-plates are tabulated. Genetic, clinical and pathological aspects are discussed aiming to provide information about these mutants which might be of great interest as animal models for human neuromuscular diseases.

Luiz Fernando Bleggi, Torres.

249

Inherited neuromuscular diseases in the mouse: a review of the literature Doenças neuromusculares hereditárias em camundongos: revisão da literatura  

Directory of Open Access Journals (Sweden)

Full Text Available There are several neuromuscular disorders affecting the human being. Most of these are poorly understood and lack an effective treatment. Due to the limitation of experimental manipulation in «anima nobili», inherited neuromuscular diseases in laboratory animals constitute a valuable source of scientific information. Amongst several animal species affected by neuromuscular disorders the house mouse is of particular interest because of its small size, short pregnancy and low costs of maintanence. In the present review 20 murine mutants with diseases affecting peripheral nerves, skeletal muscles and motor end-plates are tabulated. Genetic, clinical and pathological aspects are discussed aiming to provide information about these mutants which might be of great interest as animal models for human neuromuscular diseases.Existem inúmeras doenças neuromusculares que acometem seres humanos. A grande maioria delas é insuficientemente conhecida quanto a mecanismos fisiopatológicos e tratamentos adequados. A limitação na manipulação experimental em «anima nobili» faz-nos procurar meios alternativos para o estudo dessas doenças, tais como animais experimentais com distúrbios neuromusculares geneticamente transmitidos. Estes mutantes constituem fonte inesgotável e valiosa de informações quanto a mecanismos fisiopatogênicos e processos patológicos básicos em doenças neuromusculares. Entre as diversas espécies animais afetadas por distúrbios neuromusculares o camundongo é de particular interesse devido ao seu baixo custo de manutenção, rápida reprodutividade e pequeno tamanho, o que permite amplos estudos morfológicos a custos acessíveis. Nesta revisão analisamos 20 camundongos mutantes com distúrbios afetando nervo periférico, músculo esquelético ou junção neuromuscular. Aspectos genéticos, clínicos e patológicos são discutidos na intenção de oferecer informação atualizada sobre essas mutações animais, muitas das quais de. grande interesse como modelos experimentais de doenças neuromusculares humanas.

Luiz Fernando Bleggi Torres

1988-09-01

250

Inherited neuromuscular diseases in the mouse: a review of the literature / Doenças neuromusculares hereditárias em camundongos: revisão da literatura  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Existem inúmeras doenças neuromusculares que acometem seres humanos. A grande maioria delas é insuficientemente conhecida quanto a mecanismos fisiopatológicos e tratamentos adequados. A limitação na manipulação experimental em «anima nobili» faz-nos procurar meios alternativos para o estudo dessas d [...] oenças, tais como animais experimentais com distúrbios neuromusculares geneticamente transmitidos. Estes mutantes constituem fonte inesgotável e valiosa de informações quanto a mecanismos fisiopatogênicos e processos patológicos básicos em doenças neuromusculares. Entre as diversas espécies animais afetadas por distúrbios neuromusculares o camundongo é de particular interesse devido ao seu baixo custo de manutenção, rápida reprodutividade e pequeno tamanho, o que permite amplos estudos morfológicos a custos acessíveis. Nesta revisão analisamos 20 camundongos mutantes com distúrbios afetando nervo periférico, músculo esquelético ou junção neuromuscular. Aspectos genéticos, clínicos e patológicos são discutidos na intenção de oferecer informação atualizada sobre essas mutações animais, muitas das quais de. grande interesse como modelos experimentais de doenças neuromusculares humanas. Abstract in english There are several neuromuscular disorders affecting the human being. Most of these are poorly understood and lack an effective treatment. Due to the limitation of experimental manipulation in «anima nobili», inherited neuromuscular diseases in laboratory animals constitute a valuable source of scien [...] tific information. Amongst several animal species affected by neuromuscular disorders the house mouse is of particular interest because of its small size, short pregnancy and low costs of maintanence. In the present review 20 murine mutants with diseases affecting peripheral nerves, skeletal muscles and motor end-plates are tabulated. Genetic, clinical and pathological aspects are discussed aiming to provide information about these mutants which might be of great interest as animal models for human neuromuscular diseases.

Luiz Fernando Bleggi, Torres.

1988-09-01

251

Autophagy impairment in muscle induces neuromuscular junction degeneration and precocious aging.  

Science.gov (United States)

The cellular basis of age-related tissue deterioration remains largely obscure. The ability to activate compensatory mechanisms in response to environmental stress is an important factor for survival and maintenance of cellular functions. Autophagy is activated both under short and prolonged stress and is required to clear the cell of dysfunctional organelles and altered proteins. We report that specific autophagy inhibition in muscle has a major impact on neuromuscular synaptic function and, consequently, on muscle strength, ultimately affecting the lifespan of animals. Inhibition of autophagy also exacerbates aging phenotypes in muscle, such as mitochondrial dysfunction, oxidative stress, and profound weakness. Mitochondrial dysfunction and oxidative stress directly affect acto-myosin interaction and force generation but show a limited effect on stability of neuromuscular synapses. These results demonstrate that age-related deterioration of synaptic structure and function is exacerbated by defective autophagy. PMID:25176656

Carnio, Silvia; LoVerso, Francesca; Baraibar, Martin Andres; Longa, Emanuela; Khan, Muzamil Majid; Maffei, Manuela; Reischl, Markus; Canepari, Monica; Loefler, Stefan; Kern, Helmut; Blaauw, Bert; Friguet, Bertrand; Bottinelli, Roberto; Rudolf, Rüdiger; Sandri, Marco

2014-09-11

252

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

253

Synthesis of dissipative output feedback controllers. Application to mechanical systems  

Energy Technology Data Exchange (ETDEWEB)

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

Johannessen, Erling Aarsand

1997-12-31

254

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

255

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

256

Evaluation of skeletal muscular involvement in neuromuscular disorders with thallium-201 whole body scintigraphy  

International Nuclear Information System (INIS)

The extent as well as severity of pathologic changes of skeletal muscles were analyzed with thallium-201 whole body scintigraphy (WBS) in 29 cases of various types of neuromuscular diseases (18 cases of myogenic and 11 cases of neurogenic muscular diseases) and 14 cases of normal controls. After intravenous injection of 2 mCi of thallium-201 chloride, WBS was performed for 15 minutes using a gamma camera with twin-opposed large rectangular detectors. Counts at brachia, forearms, thighs, and calves were assessed after reconstruction of the scintigram of the whole body by taking the geometric mean of the anterior and posterior data. WBS showed uniform tracer activities in the 4 extremities in 12 cases among 14 controls. Laterality in distribution of counts of both legs and arms was noted in the remaining 2 controls. WBS revealed decrease of perfusion in the extremities with muscular atrophy and/or weakness in neuromuscular diseases. The overall diagnostic accuracy of WBS for evaluation of skeletal muscle involvement was 75 to 80 % except for the bilateral brachia for which it decreased to 65 %. All of the three cases of muscular dystrophy with pseudohypertrophy of the calves or thighs showed unequivocal decrease of perfusion of those regions in WBS. In conclusion, thallium-201 WBS was considered to be a useful clinical means in evaluating the extent and severity of muscular involvement of various types of neuromuscular disorders. (author)

257

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

258

Neuromuscular blockade in cardiac surgery: an update for clinicians.  

Science.gov (United States)

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. PMID:18603747

Hemmerling, Thomas M; Russo, Gianluca; Bracco, David

2008-01-01

259

Monitoring of neuromuscular transmission by electromyography during anaesthesia. A comparison with mechanomyography in cat and man.  

Science.gov (United States)

In this study the applicability of the electromyographical method for monitoring neuromuscular transmission during anaesthesia has been investigated. The purpose was to determine the stability and temperature dependence of the EMG and to evaluate and compare EMG area, amplitude and duration during a non-depolarizing neuromuscular block in the tibialis anterior muscle preparation of the cat. Further, in clinical studies the purpose was to investigate differential hand muscle sensitivity to non-depolarizing neuromuscular blocking agents based on the EMG and the standard adductor pollicis mechanomyogram, and to establish the agreement between the electromyographical and the mechanomyographical methods and their relationship to clinical parameters of residual neuromuscular block. For this purpose a new monitoring equipment was developed for simultaneous recording of the evoked mechanomyogram and the surface compound EMG area, amplitude and duration. In the animal studies the EMG was found to be stable with changes less than 10% during 3 hours of stimulation and with a high degree of reproducibility. In contrast, the mechanomyogram proved unstable over time with changes of 35-50% (positive staircase) within minutes after onset of stimulation followed by a slower decline of the response to 70-75% of control. An inverse relationship was found between temperature and both the mechanomyogram and the EMG, the EMG area and duration being more affected (5-7% per degrees C) than EMG amplitude (2-3% per degrees C). During onset and recovery from non-depolarizing neuromuscular block, EMG area and amplitude of the first major negative deflection and of the total compound response both reflected neuromuscular transmission equally. The EMG duration was found to be unsuitable as a predictor of neuromuscular block. In the clinical studies of the hand muscles (adductor pollicis, hypothenar and first dorsal interosseous muscles) small but clinically insignificant differences in EMG-based sensitivity to pancuronium were observed. There was no difference between EMG area and amplitude in the estimated effective doses of pancuronium and roctronium producing 50% and 90% block, respectively (ED50 and ED90), but EMG-based sensitivity of the adductor pollicis muscle was less than when based on mechanomyography. Comparative analysis of first dorsal interosseous EMG and adductor pollicis mechanomyogram during non-depolarizing neuromuscular block was based on the concept of bias (mean difference between the results by the two methods) and limits of agreement (an estimation of how much results obtained with one method are likely to differ from the results of the other method) and evaluated during TOF nerve stimulation. The two methods agreed within acceptable limits during neuromuscular block with estimated bias being less than 2% during onset. A variable bias of 3-7% was observed during recovery, with EMG overestimating block at 25% recovery and underestimating block at 75% and 90% recovery. Limits of agreement were more narrow during onset (+/- 7-8%) than during recovery (+/- 12-17%), EMG area and amplitude equally reflected the degree of neuromascular block. First dorsal interosseous EMG TOF ratio recovered more slowly than TOF ratio of the adductor pollicis mechanomyogram during early recovery. The relationship between the two methods was described as being log-linear, and during late recovery bias between the TOF ratios of the two methods was zero. However, due to the range of deviations between the EMG and the mechanomyogram, EMG TOF ratios down to 0.55 or up to 0.90 in some patients were found to be compatible with adequate recovery of a mechanomyographical TOF ratio of 0.75. Differences between electromyographical and mechanomyographical TOF ratios in their relation to 5 s sustained headlift were only revealed when the TOF ratio was below 0.50-0.60. More patients were then able to perform the test if the TOF ratio was measured from the EMG.(ABSTRACT T PMID:8884132

Engbaek, J

1996-09-01

260

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

 
 
 
 
261

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

262

Molecular mechanisms controlling the cell cycle in embryonic stem cells.  

Science.gov (United States)

Embryonic stem (ES) cells are originated from the inner cell mass of a blastocyst stage embryo. They can proliferate indefinitely, maintain an undifferentiated state (self-renewal), and differentiate into any cell type (pluripotency). ES cells have an unusual cell cycle structure, consists mainly of S phase cells, a short G1 phase and absence of G1/S checkpoint. Cell division and cell cycle progression are controlled by mechanisms ensuring the accurate transmission of genetic information from generation to generation. Therefore, control of cell cycle is a complicated process, involving several signaling pathways. Although great progress has been made on the molecular mechanisms involved in the regulation of ES cell cycle, many regulatory mechanisms remain unknown. This review summarizes the current knowledge about the molecular mechanisms regulating the cell cycle of ES cells and describes the relationship existing between cell cycle progression and the self-renewal. PMID:23955576

Abdelalim, Essam M

2013-12-01

263

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

264

Memory blocking in schizophrenia reflects deficient retrieval control mechanisms.  

Science.gov (United States)

Retrieval interference and orthographic processing were evaluated in schizophrenia, schizotypal personality disorder, and non-psychiatric control participants using a word fragment completion paradigm. Participants studied solutions and later completed corresponding fragments preceded by solutions, orthographically similar blocking words, or ampersands. Although schizophrenia patients completed fewest fragments, they showed equivalent repetition priming and blocking magnitude, supporting intact orthographic processing. Schizophrenia patients were more likely to commit intrusions in the blocking condition, whereas control participants displayed better mental control because they were more likely to withhold the response. These results suggest schizophrenia patients show abnormal functioning of control mechanisms responsible for selection and inhibition of competitors. PMID:21843925

Rass, Olga; Leynes, P Andrew; Hetrick, William P; O'Donnell, Brian F

2011-12-01

265

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

266

Study of Seed Dormancy Mechanisms; Causes and Control  

Directory of Open Access Journals (Sweden)

Full Text Available Dormancy mechanisms in cereals and oilseed crops were reviewed. Objective was to determine the causes of seed dormancy. The methods of control of seed dormancy were also reviewed and the following results were obtained. During seed dormancy, a mature embryo remains inactive but viable. An understanding of seed dormancy mechanisms can be helpful in optimizing the distribution of seed germination in time or space. Seed coats, cotyledons and growth hormones play an important role in maintaining seed dormancy. Seed dormancy can also be controlled by environment and genetic factors.

Syeda Nasreen

2002-01-01

267

The effect of increasing external degrees of freedom on force production and neuromuscular stabilisation.  

Science.gov (United States)

Evidence suggests that during interaction with different environmental dynamics the necessity to stabilise the involved joints leads to altered efficiency in force transmission to the surroundings and a specific orchestration of motor control strategies. However, little is known about the modalities of the changes associated with altered environmental dynamics. In 29 healthy participants, electromyographic (EMG) signals from four muscles of the right leg (M. peroneus longus, M. tibialis anterior, M. vastus medialis, M. gastrocnemius medialis) and three dimensions of force (Fx, Fy, Fz) were recorded. The participants were to exert force against an external object by performing a unilateral leg extension task with the task being influenced by either 0, 1 or 3 mechanical degrees of freedom. We hypothesised that the ankle stabilising muscles would increase their activities with increasing degrees of freedom (DoF), and that increasing external degrees of freedom results in decreased muscle force exerted during the movement task. The progressive change in the type of mechanical interaction from stable to unstable caused a loss of the ability to apply force in movement direction (Fz) which was accompanied by a reduction of Fy and Fx force dimensions. These reductions corresponded to maximum losses of 23% for Fz, 33% for Fx and 41% for Fy in the three degrees of freedom condition (all P muscles showed specific tuning effects, depending on the type of mechanical interaction. Our results suggest that the loss of the ability to exert force effectively against the external object is due to the neuromuscular stabilisation process of the involved joints. The change of the degrees of freedom conditions allowed for assessment of movement- or stabilisation-related adjustments of the motor system. PMID:22935007

Wuebbenhorst, Kati; Zschorlich, Volker

2012-01-01

268

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

269

Engagement and control of synchroniser mechanisms in dual clutch transmissions  

Science.gov (United States)

The study of synchroniser engagements in dual clutch transmissions is undertaken in this paper, identifying limitations to the repeatability of actuation, demonstrating one popular solution for positive synchroniser control and offering an alternate engagement tool. Principally, high wet clutch drag and the synchroniser design have lead to detrimental alignments conditions, where indexing chamfers on sleeve and target gear delay engagement of the mechanism and lead to potential sleeve block out. This paper focuses on the investigation of different control methods for overcoming these detrimental alignment conditions. The application of a closed loop control method to overcome block out related engagements is studied, and, for comparison, a novel engagement tool for overriding all chamfer alignment conditions is introduced and evaluated. Results have demonstrated that both techniques have some limitations, with the novel tool being capable of providing direct control of all chamfer engagements with limited extension of the duration of synchroniser engagements; however, some tuning of mechanism parameters is required for different engagement conditions.

Walker, Paul D.; Zhang, Nong

2012-01-01

270

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

271

PREVENÇÃO DE LESÕES EM FUTEBOLISTAS ATRAVÉS DO TREINAMENTO NEUROMUSCULAR E PROPRIOCEPTIVO EM MEMBROS INFERIORES  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To study the importance of neuromuscular and proprioceptive training in football for the prevention of sports injuries in the lower limbs. Materials and Methods: We performed a literature review using the virtual databases Bireme, Scielo and Medline. Were used articles published between 1995 and 2012. Results: The study addressed the types, location of injury in football, showed that the lower limb is more affected by injury, being physical contact or without physical contact. Intervention programs are shown effective in increasing muscular strength, muscular endurance, agility, power and increased proprioception. Discussion: Due to the different mechanisms responsible for the injuries and the considerable increase of injuries in high performance sports, the study of means to prevent injury was drafted. Many studies have shown the effectiveness of training programs and proprioceptive neuromuscular to reduce the number of injuries during the season and to reduce the distance between the matches. Low cost programs may reduce the incidence of injuries in football. Conclusion: The neuromuscular and proprioceptive training can prevent injuries in football players due to the protective action in joints and muscles, should being included in the training of athletes.

Léo de Paiva Montenegro

2014-02-01

272

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

273

[Neuromuscular relaxation and CCMDP. The Zilgrei and Feldenkrais methods 2].  

Science.gov (United States)

The Authors show two neuromuscular release methods employed in the treatment of cranio-cervico-mandibular syndrome; these methods work at the place of origin of the pathology resolving the symptoms in different districts of the body. PMID:2701432

Santoro, F; Maiorana, C; Faccin, C

1989-10-31

274

Performance Analysis of Concurrency Control Mechanisms for OLTP Databases  

Directory of Open Access Journals (Sweden)

Full Text Available Concurrency control (CC in distributed and multidimensional databases is becoming more important due to recent increase in high-volume data storage with increasing online transaction processing (OLTP requirements for medium and large organisations. This paper examines three concurrency control mechanisms commonly adopted and analyses their performance in distributed databases for OLTP operational systems of enterprises. The three CC mechanisms investigated are, two phase locking (2PL, wait depth limited (WDL and optimistic concurrency control. These CC mechanisms have been studied well in disk-based systems. However, with the recent advances of cost-effective main memory or in-memory storage that can support much higher transaction rates than disk-based systems, there is sufficient motivation to re-investigate the performance of such CC mechanisms in diverse processor configurations. This paper presents a comparison of their behaviour and performance in terms of throughput rates achieved with varying transaction size and contention. The outcome of this study has resulted in further research proposals for improving the performance of these CC mechanisms for OLTP databases.

Samuel Kaspi

2014-08-01

275

Experience with control rod drive mechanism of FBTR  

International Nuclear Information System (INIS)

This paper explains the principle of operation of Control Rod Drive Mechanism (CRDM) in Fast Breeder Test Reactor (FBTR) which is a 40 MWt loop type reactor. It discusses the problems faced and solutions evolved during testing of CRDM in air and in sodium and during operation in reactor. Surveillance tests carried out with CRDMs in pile are also discussed. (author). 2 figs

276

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

277

Control rod drive mechanism test program. Revision 3  

International Nuclear Information System (INIS)

A description is given of the testing and development of three control rod drive mechanisms for use on commercial PWR plants designed by B and W. The test results indicate that all three drives are reliable and ensure safe, dependable reactor operation

278

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

279

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

280

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.)

 
 
 
 
281

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

282

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

283

Changes in masseter muscle trigger points following strain-counterstrain or neuro-muscular technique.  

Science.gov (United States)

The aim of this study was to compare the immediate effects, on pressure pain sensitivity and active mouth opening, following the application of neuromuscular or strain/counter-strain technique in latent myofascial trigger points (MTrPs) in the masseter muscle. Seventy-one subjects, 34 men and 37 women, aged 20-65 years old, participated in this study. Subjects underwent a screening process to establish the presence of MTrPs in the masseter muscle. Subjects were divided randomly into three groups: group A which was treated with a neuromuscular intervention, group B treated with the strain/counter-strain technique, and group C as control group. Each treatment group received a weekly treatment session during 3 consecutive weeks. Outcomes measures were pressure pain thresholds (PPTs), active mouth opening and local pain (visual analogue scale, VAS) elicited by the application of 2.5kg/cm(2) of pressure over the MTrP. They were captured at baseline and 1 week after discharge by an assessor blinded to the treatment allocation of the subject. The ANOVA found a significant groupxtime interaction (F=25.3; pactive mouth opening (F=10.5; p1) for PPT and mouth opening, and moderate for local pain (d0.8). Our results suggest that neuromuscular or strain/counter-strain technique might be employed in the management of latent MTrPs in the masseter muscle. PMID:19118788

Ibáñez-García, Jordi; Alburquerque-Sendín, Francisco; Rodríguez-Blanco, Cleofás; Girao, Didac; Atienza-Meseguer, Albert; Planella-Abella, Sergi; Fernández-de-Las Peñas, César

2009-01-01

284

Rapid synthesis of acetylcholine receptors at neuromuscular junctions. (Reannouncement with new availability information)  

Energy Technology Data Exchange (ETDEWEB)

The rate of acetylcholine receptor (AChR) degradation in mature, innervated mammalian neuromuscular junctions has recently been shown to be biphasic; up to 20% are rapidly turned over whereas the remainder are lost more slowly. In order to maintain normal junctional receptor density, synthesis and insertion of AChRs should presumably be sufficiently rapid to replace both the RTOs and the stable receptors. The authors have tested this prediction by blocking pre-existing AChRs in the mouse sternomastoid muscle with alpha bungarotoxin and monitoring the subsequent appearance of new junctional AChRs at intervals of 3 h to 20 days by labelling them. The results show that new receptors were initially inserted rapidly. The rate of increase of new binding sites gradually slowed down during the remainder of the time period studied. Control observations excluded possible artifacts of the experimental procedure including incomplete blockade of AChRs, dissociation of toxin receptor complexes, or experimentally induced alteration of receptor synthesis. The present demonstration of rapid synthesis and incorporation of AChRs at innervated neuromuscular junctions provides support for the concept of a subpopulation of rapidly turned over AChRs. The RTOs may serve as precursors for the large population of stable receptors and have an important role in the metabolism of the neuromuscular synapse.

Ramsay, D.A.; Drachman, D.B.; Pestronk, A.

1988-12-31

285

Modeling neuromuscular effects of ankle foot orthoses (AFOs) in computer simulations of gait.  

Science.gov (United States)

Ankle foot orthoses (AFOs) provide immediate changes to gait kinematics and alter EMG-recorded muscle activity during gait; yet our understanding of neuromuscular adaptations while using AFOs remains incomplete. To address this, we have developed a tunable AFO model to predict torque from ankle angle and velocity and to identify plausible changes in muscle excitation and function in a walking simulation. Using a dynamometer in passive mode, we isolated flexion/extension torque of three polypropylene spring leaf AFOs at 5 degrees/s, 30 degrees/s and 120 degrees/s, from which a model of AFO torque as a function of deformation angle, velocity and size was derived with predictive ability of R2>0.9. The model coefficients did not vary linearly with size, illustrating the need to test AFO deformation response individually. We applied the tuned models to simulations of normal healthy gait to isolate AFO-induced neuromuscular changes. Compared to the No-AFO condition, AFO results show decreased net tibialis anterior excitation. Our results also show that net soleus excitation is not diminished with an AFO although soleus-induced ankle accelerations were reduced. With a tunable AFO model applied to walking simulations, we can quantify the contributions of muscle and orthosis to net joint torque and predict changes in neuromuscular control during walking. PMID:18657977

Crabtree, Charles A; Higginson, Jill S

2009-01-01

286

Mechanisms in Environmentally-Assisted One-photon Phase Control  

CERN Document Server

The ability of an environment to assist in one-photon phase control relies upon entanglement between the system and bath and on the breaking of the time reversal symmetry. Here, one photon phase control is examined analytically and numerically in a model system, allowing an analysis of the relative strength of these contributions. Further, the significant role of non-Markovian dynamics and of moderate system-bath coupling in enhancing one-photon phase control is demonstrated, and an explicit role for quantum mechanics is noted in the existence of initial non-zero stationary coherences. Finally, desirable conditions are shown to be required to observe such environmentally assisted control, since the system will naturally equilibrate with its environment at longer times, ultimately resulting in the loss of phase control.

Pachon, Leonardo A

2013-01-01

287

Vendaje neuromuscular: Efectos neurofisiológicos y el papel de las fascias / Neuromuscular Bandage: Neurophysiological Effects and the Role of Fascias / Bandagem neuromuscular: Efeitos neurofisiológicos e o papel das fáscia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in portuguese Durante os últimos anos a bandagem neuromuscular, um aplicativo terapêutico criado em 1979 pelo doutor KJenzo Kase tem vindo se introduzindo no maneio de muitas alterações do sistema musculoesquelético e especialmente no tratamento de transtornos neurológicos; esta ferramenta terapêutica que consist [...] e em uma bandagem elástica autoadesiva, permite a recuperação da parte lesada sem diminuir sua função corporal. De acordo com a literatura existente sobre os efeitos fisiológicos produzidos por este aplicativo terapêutico no organismo poderia se dizer que existe consenso. No entanto, neste artigo a autora quer destacar o significativo ainda pouco destacado papel que jogam as fáscias nos efeitos terapêuticos da bandagem neuromuscular, analisando desde uma perspectiva reflexiva o efeito analgésico, neuromecânico e circulatório, como efeitos fundamentais da bandagem neuromuscular e a função das fáscias, tentando aportar um entendimento global na forma como se relacionam todos os tecidos conectivos, aspectos que são de grande importância tanto para a avaliação de alterações quanto para a prescrição adequada da bandagem neuromuscular. Abstract in spanish Durante los últimos años, el vendaje neuromuscular, un aplicativo terapéutico creado en 1979 por el doctor Kenzo Kase, ha venido introduciéndose en el manejo de muchas alteraciones del sistema músculo-esquelético y más aún en el tratamiento de trastornos neurológicos; esta herramienta terapéutica qu [...] e consiste en un vendaje elástico autoadhesivo permite la recuperación de la parte lesionada sin disminuir su función corporal. De acuerdo con la literatura existente sobre los efectos fisiológicos producidos por este aplicativo terapéutico en el organismo, se podría decir que existe consenso. Sin embargo, en este artículo la autora quiere destacar el significativo aunque poco resaltado papel que juegan las fascias en los efectos terapéuticos del vendaje neuromuscular, analizando desde una perspectiva reflexiva el efecto analgésico, neuromecánico y circulatorio, como efectos fundamentales del vendaje neuromuscular y la función de las fascias en los mismos, con lo que intenta aportar un entendimiento global en la manera como se relacionan todos los tejidos conectivos, aspectos que son de gran importancia tanto para la evaluación de alteraciones como para la prescripción adecuada del vendaje neuromuscular. Abstract in english During the last years, neuromuscular bandage, a therapeutic application created in 1979 by doctor Kenzo Kase has been introduced in the management of many disorders of the musculo-skeletal system and even more so in the treatment of neurological disorders; This therapeutic tool which consists of a s [...] elf adhesive elastic bandage allows recovery of the injured party without diminish- ing its bodily function. According to the existing literature on the physiological effects of this therapeutic application in the body, you could say that there is consensus. However in this article the author wants to highlight the significant although little highlighted role played by the fascias on the therapeutic effects of neuromuscular bandage, analyzing from a reflective perspective the analgesic, neuromechanical and circulatory effects, as fundamental effects of neuromuscular bandage and fascias in the same function, trying to bring a global understanding on the way they relate to all connective tissues, aspects that are of great importance for the proper evaluation of alterations and prescription of neuromuscular bandage.

Ximena María, Villota Chicaíza.

2014-08-01

288

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)

289

Synapsin regulates activity-dependent outgrowth of synaptic boutons at the Drosophila neuromuscular junction.  

Science.gov (United States)

Patterned depolarization of Drosophila motor neurons can rapidly induce the outgrowth of new synaptic boutons at the larval neuromuscular junction (NMJ), providing a model system to investigate mechanisms underlying acute structural plasticity. Correlative light and electron microscopy analysis revealed that new boutons typically form near the edge of postsynaptic reticulums of presynaptic boutons. Unlike mature boutons, new varicosities have synaptic vesicles which are distributed uniformly throughout the bouton and undeveloped postsynaptic specializations. To characterize the presynaptic mechanisms mediating new synaptic growth induced by patterned activity, we investigated the formation of new boutons in NMJs lacking synapsin [Syn(-)], a synaptic protein important for vesicle clustering, neurodevelopment, and plasticity. We found that budding of new boutons at Syn(-) NMJs was significantly diminished, and that new boutons in Syn(-) preparations were smaller and had reduced synaptic vesicle density. Since synapsin is a target of protein kinase A (PKA), we assayed whether activity-dependent synaptic growth is regulated via a cAMP/PKA/synapsin pathway. We pretreated preparations with forskolin to raise cAMP levels and found this manipulation significantly enhanced activity-dependent synaptic growth in control but not Syn(-) preparations. To examine the trafficking of synapsin during synaptic growth, we generated transgenic animals expressing fluorescently tagged synapsin. Fluorescence recovery after photobleaching analysis revealed that patterned depolarization promoted synapsin movement between boutons. During new synaptic bouton formation, synapsin redistributed upon stimulation toward the sites of varicosity outgrowth. These findings support a model whereby synapsin accumulates at sites of synaptic growth and facilitates budding of new boutons via a cAMP/PKA-dependent pathway. PMID:25100589

Vasin, Alexander; Zueva, Lidia; Torrez, Carol; Volfson, Dina; Littleton, J Troy; Bykhovskaia, Maria

2014-08-01

290

Effect of movement velocity during resistance training on neuromuscular performance.  

Science.gov (United States)

This study aimed to compare the effect on neuromuscular performance of 2 isoinertial resistance training programs that differed only in actual repetition velocity: maximal intended (MaxV) vs. half-maximal (HalfV) concentric velocity. 21 resistance-trained young men were randomly assigned to a MaxV (n=10) or HalfV (n=11) group and trained for 6 weeks using the full squat exercise. A complementary study (n=8) described the acute metabolic and mechanical response to the protocols used. MaxV training resulted in a likely more beneficial effect than HalfV on squat performance: maximum strength (ES: 0.94 vs. 0.54), velocity developed against all (ES: 1.76 vs. 0.88), light (ES: 1.76 vs. 0.75) and heavy (ES: 2.03 vs. 1.64) loads common to pre- and post-tests, and CMJ height (ES: 0.63 vs. 0.15). The effect on 20-m sprint was unclear, however. Both groups attained the greatest improvements in squat performance at their training velocities. Movement velocity seemed to be of greater importance than time under tension for inducing strength adaptations. Slightly higher metabolic stress (blood lactate and ammonia) and CMJ height loss were found for MaxV vs. HalfV, while metabolite levels were low to moderate for both conditions. MaxV may provide a superior stimulus for inducing adaptations directed towards improving athletic performance. PMID:24886926

Pareja-Blanco, F; Rodríguez-Rosell, D; Sánchez-Medina, L; Gorostiaga, E M; González-Badillo, J J

2014-10-01

291

Electrophysiological analysis of transmission at the skeletal neuromuscular junction.  

Science.gov (United States)

The review is divided into two sections. The first deals with methods and problems associated with performing electrophysiological experimentation on the skeletal muscle neuromuscular junction. The second section concentrates on the computer analysis of electrophysiological data. In the first section, the various techniques available for producing skeletal muscle paralysis are described. These include the use of pharmacological manipulations, such as an excess of magnesium ions or a competitive postjunctional nicotinic acetylcholine antagonist, physiological manipulations, such as cutting the muscle fibers, and the muscle fiber sodium channel toxin, mu-conotoxin. Also, in this section, a comparison is made of the use of voltage- and current-recording techniques, including descriptions of, and solutions to, the problems associated with membrane capacitance, nonlinear summation, membrane space constant, and electrical and mechanical interference. In the second section, details are given of the types of computer system commonly used for the analysis of electrophysiological data and also the requirements of the data analysis software. The use of computer algorithms for signal detection, signal evaluation, signal averaging, and curve fitting are qualitatively described, along with some of the problems and pitfalls often associated with these methods. PMID:8241541

Prior, C; Dempster, J; Marshall, I G

1993-09-01

292

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.

293

Controlling chaos based on an adaptive nonlinear compensator mechanism  

International Nuclear Information System (INIS)

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

294

A nuclear reactor equipped with a control mechanism  

International Nuclear Information System (INIS)

The invention relates to a control mechanism for an LMFBR type reactor, to ensure a fast power drop by varying the reactivity of an appropriate amount to meet the conditions of continuous operation in complete safety should there be a partial drop in the flow or pressure of the coolant. Control rods in a neutron absorbing material are used to regulate the reactivity of the reactor. At least one control rod is sensitive to a triggering signal so as to be introduced in the reactor core in two successive stages, first by uncontrolled unidirectional injection and, secondly, by controlled introduction. The uncontrolled unidirectional injection may be carried out by free drop or by propulsion under the effect of stored energy

295

Electromagnetic analysis of control element drive mechanism for KSNP  

International Nuclear Information System (INIS)

The magnetic jack type Control Element Drive Mechanism (CEDM) for Korean Standard Nuclear Power Plant (KSNP) is an electromechanical device which provides controlled linear motion to the Control Element Assembly (CEA) through the Extension Shaft Assembly (ESA) in response to operational signals received from the Control Element Drive Mechanism Control System (CEDMCS). The CEDM is operated by applying localized magnetic flux fields to movable latch and lift magnets, which are in the coolant pressure boundary. The CEDM design had been developed through electromechanical testing of the system including the magnetic force lifting the ESA. But it will be inefficient if parametric studies should be performed to improve the CEDM by test due to the consumption of high cost and long duration. So it becomes necessary to develop a computational model to simulate the electromagnetic characteristics of the CEDM to improve the CEDM design efficiently. In this paper, the electromagnetic analysis using a 2D finite element model has been carried out to simulate magnetic force of the lift magnet of the CEDM, to provide effective evaluation between leakage flux and lift force and to compare with test results. Analysis results show the lift force satisfied the test results and design requirement and the lift force depend on the shape of the components, leakage flux and B-H curve

296

Analysis of femtosecond quantum control mechanisms with colored double pulses  

International Nuclear Information System (INIS)

Fitness landscapes based on a limited number of laser pulse shape parameters can elucidate reaction pathways and can help to find the underlying control mechanism of optimal pulses determined by adaptive femtosecond quantum control. In a first experiment, we employ colored double pulses and systematically scan both the temporal subpulse separation and the relative amplitude of the two subpulses to acquire fitness landscapes. Comparison with results obtained from a closed-loop experiment demonstrates the capability of fitness landscapes for the revelation of possible control mechanisms. In a second experiment, using transient absorption spectroscopy, we investigate and compare the dependence of the excitation efficiency of the solvated dye molecule 5,5'-dichloro-11-diphenylamino-3,3'-diethyl-10,12-ethylene thiatricarbocyanine perchlorate (IR140) on selected pulse shapes in two parametrizations. The results show that very different pulse profiles can be equivalently adequate to maximize a given control objective. Fitness landscapes thus provide valuable information about different pathways along which a molecular system can be controlled with shaped laser pulses

297

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.

298

Comprehensive dust control technology of mechanized longwall caving face  

Energy Technology Data Exchange (ETDEWEB)

A comprehensive dust control technology for mechanized longwall caving face is evaluated systematically. The evaluation has included the technique of thick seam water injection (borehole arrangement, hole sealing and injection parameters), high pressure spray jet of the shearer, automatic water spraying during relocation of powered supports and coal discharge and auto-sonic atomizer on the coal crusher, and the application results. Based on the dust control technology in China and abroad, this paper discusses the developmental tendency of the technology. 3 refs., 4 figs., 2 tabs.

Zhang, Y. [Central Coal Mining Research Institute (China). Chongqing Branch

1995-10-01

299

Quality control of injection moulded micro mechanical parts  

DEFF Research Database (Denmark)

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

Gasparin, Stefania; Tosello, Guido

2009-01-01

300

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

 
 
 
 
301

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

302

Mechanization and Control Concepts for Biologically Inspired Micro Aerial Vehicles  

Science.gov (United States)

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

Raney, David L.; Slominski, Eric C.

2003-01-01

303

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.)

304

Model Predictive Vibration Control Efficient Constrained MPC Vibration Control for Lightly Damped Mechanical Structures  

CERN Document Server

Real-time model predictive controller (MPC) implementation in active vibration control (AVC) is often rendered difficult by fast sampling speeds and extensive actuator-deformation asymmetry. If the control of lightly damped mechanical structures is assumed, the region of attraction containing the set of allowable initial conditions requires a large prediction horizon, making the already computationally demanding on-line process even more complex. Model Predictive Vibration Control provides insight into the predictive control of lightly damped vibrating structures by exploring computationally efficient algorithms which are capable of low frequency vibration control with guaranteed stability and constraint feasibility. In addition to a theoretical primer on active vibration damping and model predictive control, Model Predictive Vibration Control provides a guide through the necessary steps in understanding the founding ideas of predictive control applied in AVC such as: ·         the implementation of ...

Takács, Gergely

2012-01-01

305

Mechanical spin control of nitrogen-vacancy centers in diamond.  

Science.gov (United States)

We demonstrate direct coupling between phonons and diamond nitrogen-vacancy (NV) center spins by driving spin transitions with mechanically generated harmonic strain at room temperature. The amplitude of the mechanically driven spin signal varies with the spatial periodicity of the stress standing wave within the diamond substrate, verifying that we drive NV center spins mechanically. These spin-phonon interactions could offer a route to quantum spin control of magnetically forbidden transitions, which would enhance NV-based quantum metrology, grant access to direct transitions between all of the spin-1 quantum states of the NV center, and provide a platform to study spin-phonon interactions at the level of a few interacting spins. PMID:24329469

MacQuarrie, E R; Gosavi, T A; Jungwirth, N R; Bhave, S A; Fuchs, G D

2013-11-27

306

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

307

Molecular Forces and Mechanisms Controlling Receptor-mediated Bioadhesion  

Science.gov (United States)

In contrast to adhesion between nonbiological materials, strong biological adhesion is controlled primarily by strong, specific short-range forces between discreet receptors (locks) and ligands (keys). In solution, the receptor-ligand bond strengths are determined by the intermolecular contacts between the ligand and the receptor binding site. By contrast, at membrane surfaces, the effective bond strengths are also influenced by a variety of factors that range from the interfacial structure to the mechanisms of adhesive failure. In this work, we used the surface force apparatus to identify molecular forces and mechanisms that modulate the strength of receptor-ligand bonds at membrane surfaces. These interactions were modulated by the colloidal forces acting at the membrane surface, and sensed perturbations within only a few angstroms of the membrane. Moreover, the strength of receptor-mediated adhesion depends on both the membrane fluidity and on the mechanism of adhesive failure. By direct measurement, we demonstrated that, for these discreet cross-bridges, the critical detachment force is not determined by the 'bond' energy, but by the gradient of the bond energy. These findings indicate the rich variety of mechanisms by which biological systems can regulate adhesion, and suggest that bioadhesion may be regulated in vivo both by the modulation of specific receptor-ligand bond strengths and by control of their attachments to underlying substrata.

Leckband, D. E.

1996-03-01

308

BEN/SC1/DM-GRASP expression during neuromuscular development: a cell adhesion molecule regulated by innervation.  

Science.gov (United States)

BEN/SC1/DM-GRASP is a cell adhesion molecule belonging to the Ig superfamily that is transiently expressed during avian embryogenesis in a variety of cell types, including the motoneurons of the spinal cord. We have investigated the pattern of BEN expression during neuromuscular development of the chick. We show that both motoneurons and their target myoblasts express BEN during early embryonic development and that the protein becomes restricted at neuromuscular contacts as soon as postsynaptic acetylcholine receptor clusters are observed in muscle fibers. Muscle cells grown in vitro express and maintain BEN expression even when they fuse and give rise to mature myotubes. When embryos are deprived of innervation by neural tube ablation, BEN expression is observed in muscle fibers, whereas, in control, the protein is already restricted at neuromuscular synaptic sites. These results demonstrate that all myogenic cells intrinsically express BEN and maintain the protein in the absence of innervation. Conversely, when neurons are added to myogenic cultures, BEN is rapidly downregulated in muscle cells, demonstrating that innervation controls the restricted pattern of BEN expression seen in innervated muscles. After nerve section in postnatal muscles, BEN protein becomes again widely spread over muscle fibers. When denervated muscles are allowed to be reinnervated, the protein is reexpressed in regenerating motor axons, and reinnervation of synaptic sites leads to the concentration of BEN at neuromuscular junctions. Our results suggest that BEN cell adhesion molecule acts both in the formation of neuromuscular contacts during development and in the events leading to muscle reinnervation. PMID:9952415

Fournier-Thibault, C; Pourquié, O; Rouaud, T; Le Douarin, N M

1999-02-15

309

Conceptual Design of Bottom-mounted Control Rod Drive Mechanism  

International Nuclear Information System (INIS)

The arrangement of the BMCRDMs and irradiation holes in the core is therefore easier than that of the top-mounted CRDM. Hence, many foreign research reactors, such as JRR-3M, JMTR, OPAL, and CARR, have adopted the BMCRDM concept. The purpose of this paper is to introduce the basic design concept on the BMCRDM. The major differences of the CRDMs between HANARO and KJRR are compared, and the design features and individual system of the BMCRDM for the KJRR are described. The Control Rod Drive Mechanism (CRDM) is a device to regulate the reactor power by changing the position of a Control Absorber Rod (CAR) and to shut down the reactor by fully inserting the CAR into the core within a specified time. The Bottom-Mounted CRDM (BMCRDM) for the KiJang Research Reactor (KJRR) is a quite different design concept compared to the top-mounted CRDM such as HANARO and JRTR. The main drive mechanism of the BMCRDM is located in a Reactivity Control Mechanism (RCM) room under the reactor pool bottom, which makes the interference with equipment in the reactor pool reduced

310

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

311

Conceptual Design of Bottom-mounted Control Rod Drive Mechanism  

Energy Technology Data Exchange (ETDEWEB)

The arrangement of the BMCRDMs and irradiation holes in the core is therefore easier than that of the top-mounted CRDM. Hence, many foreign research reactors, such as JRR-3M, JMTR, OPAL, and CARR, have adopted the BMCRDM concept. The purpose of this paper is to introduce the basic design concept on the BMCRDM. The major differences of the CRDMs between HANARO and KJRR are compared, and the design features and individual system of the BMCRDM for the KJRR are described. The Control Rod Drive Mechanism (CRDM) is a device to regulate the reactor power by changing the position of a Control Absorber Rod (CAR) and to shut down the reactor by fully inserting the CAR into the core within a specified time. The Bottom-Mounted CRDM (BMCRDM) for the KiJang Research Reactor (KJRR) is a quite different design concept compared to the top-mounted CRDM such as HANARO and JRTR. The main drive mechanism of the BMCRDM is located in a Reactivity Control Mechanism (RCM) room under the reactor pool bottom, which makes the interference with equipment in the reactor pool reduced.

Lee, Jin Haeng; Kim, Sanghaun; Yoo, Yeonsik; Cho, Yeonggarp; Kim, Dongmin; Kim, Jong In [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-05-15

312

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

313

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 d [...] os 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 Abstract in spanish 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 Abstract in english 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 aminost [...] eroid 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 acc

José Carlos, Canga; Carlos Neutzling, Lehn; Deoclécio, Tonelli; Paula de Camargo Neves, Sacco; Danielle, Beltrão; Marcelo, Kirsch; Fernando César, Serralheiro; Gustavo, Cimerman.

314

[Indications and uses of neuromuscular blocking agents in the ICU].  

Science.gov (United States)

Although many questions are still debated, some recommendations can be formulated regarding the use of neuromuscular blocking agents in the ICU. A transient curarization can be used during brief diagnostic or therapeutic procedures in order to avoid haemodynamic consequences of deep sedation. A volume controlled ventilation has to be used during the procedure. In ARDS patients, a prolonged curarization of 48 h or more is beneficial regarding systemic oxygenation, even in patients well adapted to their ventilator. The use of cisatracurium should be recommended in this context. The depth of curarization has to be checked by using a train of four stimulation at the corugator supercilii with an endpoint of 2/4 responses. A recovery from curarization should be daily envisaged if possible, in order to check the depth of the underlying sedation. In brain injured patients, a curarization can be envisaged if adaptation to the ventilator remains difficult or if normothermia or moderate hypothermia, if indicated, cannot be obtained. However, these attitudes are not based on specific data at the present time. PMID:18595649

Lagneau, F

2008-01-01

315

Using factor analysis to identify neuromuscular synergies during treadmill walking  

Science.gov (United States)

Neuroscientists are often interested in grouping variables to facilitate understanding of a particular phenomenon. Factor analysis is a powerful statistical technique that groups variables into conceptually meaningful clusters, but remains underutilized by neuroscience researchers presumably due to its complicated concepts and procedures. This paper illustrates an application of factor analysis to identify coordinated patterns of whole-body muscle activation during treadmill walking. Ten male subjects walked on a treadmill (6.4 km/h) for 20 s during which surface electromyographic (EMG) activity was obtained from the left side sternocleidomastoid, neck extensors, erector spinae, and right side biceps femoris, rectus femoris, tibialis anterior, and medial gastrocnemius. Factor analysis revealed 65% of the variance of seven muscles sampled aligned with two orthogonal factors, labeled 'transition control' and 'loading'. These two factors describe coordinated patterns of muscular activity across body segments that would not be evident by evaluating individual muscle patterns. The results show that factor analysis can be effectively used to explore relationships among muscle patterns across all body segments to increase understanding of the complex coordination necessary for smooth and efficient locomotion. We encourage neuroscientists to consider using factor analysis to identify coordinated patterns of neuromuscular activation that would be obscured using more traditional EMG analyses.

Merkle, L. A.; Layne, C. S.; Bloomberg, J. J.; Zhang, J. J.

1998-01-01

316

The kinetics of transmitter release at the frog neuromuscular junction.  

Science.gov (United States)

1. Fluctuations in the latency of focally recorded end-plate currents were analysed to determine the time course of the probabilistic presynaptic process underlying quantal release evoked after single nerve stimuli at the frog neuromuscular junction.2. The early falling phase of the presynaptic probability function can be fitted by a single exponential over two orders of magnitude of quantal release rate. The time constant of the early falling phase is about 0.5 msec at 11 degrees C, and increases with decreasing temperature with a Q(10) of at least 4 over the range 1-12 degrees C.3. After this early exponential fall, quantal release probability returns to control levels with a much slower time course.4. Conditioning nerve stimuli increase the magnitude and slightly prolong the early time course of release evoked by a test stimulus. When facilitation is calculated for matched time intervals following the conditioning and testing stimuli, it is found that the magnitude of the small, late residual tail of release is facilitated by a greater percentage than the magnitude of larger, early portions of release.5. These results are discussed in terms of the hypothesis (Katz & Miledi, 1968) that evoked release and facilitation are mediated by a common presynaptic factor which activates release in a non-linear manner. PMID:4405553

Barrett, E F; Stevens, C F

1972-12-01

317

Control and locking mechanism for nuclear reactor control rod having a liquid coolant  

International Nuclear Information System (INIS)

The invention proposes a simple control rod drive mechanism for a reactor comprising a large number of control rods, among which some have to be moved simultaneously to keep a symmetric neutron flux distribution in the core. The mechanism has a cylinder surrounding the rod; this cylinder acts as a hydraulic cylinder in which the rod slides delimiting a compression chamber. Il includes mechanical fastening means for the rod in its raised position. It comprises an electromagnetically controlled pump in the cylinder which reduces the pressure of the reactor coolant in it to raise the rod, and an electromagnetically controlled valve in the cylinder opening it to the reactor vessel and disabling the support to release the rod

318

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

319

Synchronous Controlled Switching by VCB with Electromagnetic Operation Mechanism  

Science.gov (United States)

Synchronously controlled switching to suppress transient overvoltage and overcurrent resulting from when the circuit breakers on medium voltage systems are closed is described. Firstly, by simulation it is found that if the closing time is synchronously controlled so that the contacts of the circuit breaker close completely at the instant when the voltage across contacts of the breaker at each of the three individual phases are zero, the resulting overvoltage and overcurrent is significantly suppressed when compared to conventional three phase simultaneous closing. Next, an algorithm for determining the closing timing based on a forecasted voltage zero waveform, obtained from voltage sampling data, is presented. Finally, a synchronous closing experiment of voltage 22kV utilizing a controller to implement the algorithm and a VCB with an electromagnetic operation mechanism is presented. The VCB was successfully closed at the zero point within a tolerance range of 200 microseconds.

Horinouchi, Katsuhiko; Tsukima, Mitsuru; Tohya, Nobumoto; Inoue, Ryuuichi; Sasao, Hiroyuki

320

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

 
 
 
 
321

Autoantibodies at the neuromuscular junction - link to the central nervous system.  

Science.gov (United States)

Antibodies to different membrane proteins, namely acetylcholine receptor, muscle specific kinase and low density lipoprotein receptor-related protein 4, at the neuromuscular junction are well recognised in myasthenia gravis, although the mechanisms responsible for the muscle distribution and fluctuations in function are still not very clear, and some of the issues are discussed below. In addition, the involvement of antibodies to the potassium channel complex proteins in neuromyotonia, help to lead to a better understanding of immunotherapy-responsive central nervous system diseases. PMID:25174888

Vincent, A

2014-10-01

322

Neuromuscular Disease in Childhood, a Clinicopathological Study in Iran  

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Full Text Available A prospective study of the neuromuscular diseases in Iranian children was conducted from 2000-2007 in Markaze Tebbi Koodakan, Tehran University of Medical Sciences, Tehran, Iran. Similar data are scanty outside Europe and North America. This study attempts to determine the type and relative frequency of neuromuscular diseases in Iran. One hundred and sixty five children ( < or = 16 years were assigned to an entity of neuromuscular disease following review of the clinical, biochemical and neurophysiological data and after review of most of available patients records. The common muscle diseases in Iran were muscular dystrophy (47.3%, peripheral neuropathy (17% and inflammatory myopathy (7.9%. Motor neuron disease was seen in 1.8% of cases. Of the muscular dystrophies, Duchene type (6.1% was more prevalent. History of consanguinity was present in 56%. Positive family history was seen in 15% of cases. However, 30 (18.2% cases showed no significant pathology. For this group of neuromuscular diseases further studies are needed. The study has revealed a great variety of pathology affecting children presenting with neuromuscular symptoms. The most prevalent of these were muscular dystrophies which is concordant with most other studies. The high frequency of consanguineous marriage in our cases needs further attention for social programming.

2008-01-01

323

Artificial allosteric control of proteins through mechanical tension  

Science.gov (United States)

The profound relationship between a proteins conformational change and function is one that lies at the heart of understanding, and possibly controlling biological macromolecules. Most enzymes are regulated through allosteric control, where a molecule is bound to the protein at a site other than its active site, inducing a conformational change in the protein: natures way of chemically switching a macromolecule "on" or "off." There is generally a substantial conformational change in the protein that accompanies the chemical activation of allostery, rendering the protein active to function. It is this conformational change that the protein undergoes which we can induce with externally applied mechanical tension. We exploit this ingenious method of control by chemically attaching a polymer, in this case a 60 base DNA oligomer, to various proteins which behaves as a "molecular spring". The attached DNA oligomer will become drastically rigid upon hybridization of a complementary oligomer - exerting a large enough tension to disrupt the usual function of the protein. Through this research we have developed a protein which has acquired a "switch," allowing us to control the functionality at our discretion. This artificial allosteric technique based on mechanical tension, allows us to study protein dynamics and structure with the ability to modulate the amount of tension applied to the protein. The insertion of this Allosteric Spring Probe is general, it can be applied to virtually any protein, specifically to enzymes which have defined tasks associate with notably conformational changes. This new mechanism which we have developed will lead to new approaches in bioengineering and biophysical studies, and will be the focus of my dissertation.

Choi, Brian David

324

The Influence of Age on the M Effectiveness of Neuromuscular Training to Reduce Anterior Cruciate Ligament Injury in Female Athletes  

Science.gov (United States)

Background In female athletes, sports-related injuries to the anterior cruciate ligament (ACL) increase during adolescence and peak in incidence during the mid- to late teens. Although biomechanical investigations indicate that a potential window of opportunity exists for optimal timing for the initiation of integrative neuromuscular training (NMT) in young female athletes, the influence of the timing of initiation of these programs on the efficacy of ACL injury reduction has yet to be evaluated. Hypothesis/Purpose The purpose of the current report was to systematically review and synthesize the scientific literature regarding the influence of age of NMT implementation on the effectiveness for reduction of ACL injury incidence. The hypothesis tested was that NMT would show a greater effect in younger populations. Study Design Meta-analysis; Level of evidence 1a. Methods Data were pooled from 14 clinical trials that met the inclusion criteria of (1) number of ACL injuries reported; (2) NMT program used; (3) female participants were included; (4) investigations used prospective, controlled trials; and (5) age of participants was documented or was obtainable upon contact with the authors. A meta-analysis with odds ratio (OR) was used to compare the ratios of ACL injuries between intervention and control groups among differing age categorizations. Results A meta-analysis of the 14 included studies demonstrated significantly greater knee injury reduction in female athletes who were categorized in the preventive NMT group compared with those who were in the control group (OR: 0.54; 95% confidence interval [CI]: 0.35, 0.83). Lower ACL injuries in mid-teens (OR 0.28; CI: 0.18, 0.42) compared with late teens (OR 0.48; CI: 0.21, 1.07) and early adults (OR 1.01; CI: 0.62, 1.64) were found in participants undergoing NMT. Conclusion The findings of this meta-analysis revealed an age-related association between NMT implementation and reduction of ACL incidence. Both biomechanical and the current epidemiological data indicate that the potential window of opportunity for optimized ACL injury risk reduction may be before the onset of neuromuscular deficits and peak knee injury incidence in female athletes. Specifically, it may be optimal to initiate integrative NMT programs during early adolescence, before the period of altered mechanics that increase injury risk. PMID:23048042

Myer, Gregory D.; Sugimoto, Dai; Thomas, Staci; Hewett, Timothy E.

2014-01-01

325

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

326

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

327

Patient Machine Interface for the Control of Mechanical Ventilation Devices  

Directory of Open Access Journals (Sweden)

Full Text Available The potential of Brain Computer Interfaces (BCIs to translate brain activity into commands to control external devices during mechanical ventilation (MV remains largely unexplored. This is surprising since the amount of patients that might benefit from such assistance is considerably larger than the number of patients requiring BCI for motor control. Given the transient nature of MV (i.e., used mainly over night or during acute clinical conditions, precluding the use of invasive methods, and inspired by current research on BCIs, we argue that scalp recorded EEG (electroencephalography signals can provide a non-invasive direct communication pathway between the brain and the ventilator. In this paper we propose a Patient Ventilator Interface (PVI to control a ventilator during variable conscious states (i.e., wake, sleep, etc.. After a brief introduction on the neural control of breathing and the clinical conditions requiring the use of MV we discuss the conventional techniques used during MV. The schema of the PVI is presented followed by a description of the neural signals that can be used for the on-line control. To illustrate the full approach, we present data from a healthy subject, where the inspiration and expiration periods during voluntary breathing were discriminated with a 92% accuracy (10-fold cross-validation from the scalp EEG data. The paper ends with a discussion on the advantages and obstacles that can be forecasted in this novel application of the concept of BCI.

Rolando Grave de Peralta

2013-11-01

328

Study on dynamic lifting characteristics of control rod drive mechanism  

International Nuclear Information System (INIS)

Based on the equations of the electric circuit and the magnetic circuit and analysis of the dynamic lifting process for the control rod drive mechanism (CRDM), coupled magnetic-electric-mechanical equations both for the static status and the dynamic status are derived. The analytical method is utilized to obtain the current and the time when the lift starts. The numerical simulation method of dynamic analysis recommended by ASME Code is utilized to simulate the dynamic lifting process of CRDM, and the dynamic features of the system with different design gaps are studied. Conclusions are drawn as: (1) the lifting-start time increases with the design gap, and the time for the lifting process is longer with larger gaps; (2) the lifting velocity increases with time; (3) the lifting acceleration increases with time, and with smaller gaps, the impact acceleration is larger. (author)

329

Mechanical control of heat conductivity in microscopic models of dielectrics  

CERN Document Server

We discuss a possibility to control a heat conductivity in simple one-dimensional models of dielectrics by means of external mechanical loads. To illustrate such possibilities we consider first a well-studied chain with degenerate double-well potential of the interparticle interaction. Contrary to previous studies, we consider varying length of the chain with fixed number of particles. Number of possible energetically degenerate ground states strongly depends on the overall length of the chain, or, in other terms, on average length of the link between neighboring particles. These degenerate states correspond to mechanical equilibrium, therefore one can say that the transition between them mimics to some extent a process of plastic deformation. We demonstrate that such modification of the chain length can lead to quite profound (almost five-fold) reduction of the heat conduction coefficient. Even more profound effect is revealed for a model with single-well non-convex potential. It is demonstrated that in cert...

Savin, Alexander V

2013-01-01

330

[Primary hyperparathyroidism with prevalent neuro-muscular manifestations].  

Science.gov (United States)

A case of primary hyperparathyroidism with prevalent neuromuscular symptoms is described. Clinical, diagnostic and therapeutic implications are emphasized. Particular attention must involve a full clinical examination, electromyographic data and neuromuscular biopsy to make differentiation from primary myopathy or denervation pathology. Some similarity of electromyographic data with those observed in botulism and myastenia gravis should also be taken in mind. Hypercalcemia could play a pathological role in conditioning abnormalities of nervous impulse conduction at the level of neuromuscular junction. Another possible interference might be related to a direct effect of parathormone and hypophosphataemia on nervous impulse conduction. "Glandular hyperplasia", as observed in this case at istologic examination, rises some problems as far as the prognosis is concerned. PMID:1491765

Bartolucci, L; Fioretti, M; Fioroni, E; Proietti, M G; Gradoli, C; Valori, C

1992-12-01

331

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

332

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

333

Rod drive mechanism with screw and nut for reactor control  

International Nuclear Information System (INIS)

Screw and nut mechanism for controlling a nuclear reactor by vertical travel of an assembly absorbing the neutrons in the reactor core and drop of this absorbing assembly in maximum insertion position under its own weight, for reactor scram. It comprises a mobile screw in translation, the lower end of which can be connected to the absorbing assembly through a linking rod and a fixed nut in translation, mobile in rotation, secured to the lower end of a screw holding tube, the upper end of which comprises gear for hooking the claws of the grab for holding the screw-nut assembly in vertical position

334

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

335

Tracking control mechanisms for positioning automatic CRD exchanger  

International Nuclear Information System (INIS)

Purpose: To enable completely automatic positioning for the automatic CRD (control rod drives) exchanger, as well as shorten the time for the exchanging operation and save the operator's labour. Constitution: Images of a target attached to the lower flange face of CRD are picked up by a fiber scope mounted to a mounting head. The images are converted through I.T.V. into electrical signals, passed through a cable and then sent to a pattern recognition mechanism. The position for the images of the target is calculated and the calculated position is sent to a drive control section, where the position for the images of the target is compared with a reference position for the images (exactly aligned position) and the moving amount of the mounting head is calculated to move the driving section and thereby complete the positioning. (Kawakami, Y.)

336

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

337

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Handschin, C.; Kobayashi, Y. M.; Chin, S.; Seale, P.; Campbell, K. P.; Spiegelman, B. M.

2007-01-01

338

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.