WorldWideScience
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Neuromuscular Control and Coordination during Cycling  

Science.gov (United States)

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

Li, Li

2004-01-01

2

Neuromuscular mechanisms and neural strategies in the control of time-varying muscle contractions.  

Science.gov (United States)

The organization of the neural input to motoneurons that underlies time-varying muscle force is assumed to depend on muscle transfer characteristics and neural strategies or control modes utilizing sensory signals. We jointly addressed these interlinked, but previously studied individually and partially, issues for sinusoidal (range 0.5-5.0 Hz) force-tracking contractions of a human finger muscle. Using spectral and correlation analyses of target signal, force signal, and motor unit (MU) discharges, we studied 1) patterns of such discharges, allowing inferences on the motoneuronal input; 2) transformation of MU population activity (EMG) into quasi-sinusoidal force; and 3) relation of force oscillation to target, carrying information on the input's organization. A broad view of force control mechanisms and strategies emerged. Specifically, synchronized MU and EMG modulations, reflecting a frequency-modulated motoneuronal input, accompanied the force variations. Gain and delay drops between EMG modulation and force oscillation, critical for the appropriate organization of this input, occurred with increasing target frequency. According to our analyses, gain compensation was achieved primarily through rhythmical activation/deactivation of higher-threshold MUs and secondarily through the adaptation of the input's strength expected during tracking tasks. However, the input's timing was not adapted to delay behaviors and seemed to depend on the control modes employed. Thus, for low-frequency targets, the force oscillation was highly coherent with, but led, a target, this timing error being compatible with predictive feedforward control partly based on the target's derivatives. In contrast, the force oscillation was weakly coherent, but in phase, with high-frequency targets, suggesting control mainly based on a target's rhythm. PMID:23803326

Erimaki, Sophia; Agapaki, Orsalia M; Christakos, Constantinos N

2013-09-01

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NEUROMUSCULAR CONTROL IN LUMBAR DISORDERS  

Directory of Open Access Journals (Sweden)

Full Text Available Impaired motor and sensory functions have been associated with low back pain (LBP. This includes disturbances in a wide range of sensorimotor control e.g. sensory dysfunctions, impaired postural responses and psychomotor control. However, the physiological mechanisms, clinical relevance and characteristics of these findings in different spinal pathologies require further clarification. The purposes of this study were to investigate postural control, lumbar muscle function, movement perception and associations between these findings in healthy volunteers (n=35, patients with lumbar disc herniation (n=20 and lumbar spinal stenosis (LSS, n=26. Paraspinal muscle responses for sudden upper limb loading and muscle activation during flexion-extension movement and the lumbar endurance test were measured by surface electromyography (EMG. Postural stability was measured on a force platform during two- and one-footed standing. Lumbar movement perception was assessed in a motorised trunk rotation unit in the seated position. In addition, measurements of motor-(MEP and somatosensory evoked potentials (SEP and needle EMG examination of lumbar multifidus muscles were performed in the LSS patients. Clinical and questionnaire data were also recorded. A short latency paraspinal muscle response (~50 ms for sudden upper limb loading was observed. The latency of the response was shortened by expectation (p=0.017. The response latency for unexpected loading was similar in healthy persons and disc herniation patients but the latency was not shortened by expectation in the patients (p = 0.014. Also impaired postural control (p < 0.05 and lumbar movement perception (p = 0.012 were observed in disc herniation patients. The impaired lumbar movement perception (p=0.054 and anticipatory muscle activation (p = 0.043 tended to be restored after successful surgery but postural control had still not recovered after 3 months of follow-up. The majority of LSS patients were unable to sense a rotational movement in the lumbar area and thus had clearly impaired lumbar movement perception (p = 0.006. Abnormal MEPs had only inconsistent and SEPs showed no associations with impaired movement perception and postural stability in LSS. Abnormal needle EMG findings and flexion-extension activation of paraspinal muscles were frequently observed in LSS patients. Lumbar paraspinal muscle endurance was better than in previously evaluated healthy subjects and chronic LBP patients (p < 0.001. The results demonstrated clearly impaired lumbar sensory and motor function in sciatica and LSS patients. The pure reflex activation of paraspinal muscles was not affected in sciatica but a difference was found in the premotoneuronal response control. The impaired proprioceptive functions and premotoneuronal response control seem to recover at least partially but the maintenance of postural stability is a complex activity which does not seem to recover automatically in operated sciatica patients at least in three months follow-up. Paraspinal muscle denervation and dysfunction were clearly detectable in LSS but lumbar paraspinal muscle endurance was unexpectedly good.

Ville Leinonen

2004-03-01

4

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

OpenAIRE

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

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

2012-01-01

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Invasive home mechanical ventilation, mainly focused on neuromuscular disorders  

OpenAIRE

Introduction and background: Invasive home mechanical ventilation is used for patients with chronic respiratory insufficiency. This elaborate and technology-dependent ventilation is carried out via an artificial airway (tracheal cannula) to the trachea. Exact numbers about the incidence of home mechanical ventilation are not available. Patients with neuromuscular diseases represent a large portion of it. Research questions: Specific research questions are formulated and answered concerning th...

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

2010-01-01

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

Science.gov (United States)

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  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction and background: Invasive home mechanical ventilation is used for patients with chronic respiratory insufficiency. This elaborate and technology-dependent ventilation is carried out via an artificial airway (tracheal cannula to the trachea. Exact numbers about the incidence of home mechanical ventilation are not available. Patients with neuromuscular diseases represent a large portion of it. Research questions: Specific research questions are formulated and answered concerning the dimensions of medicine/nursing, economics, social, ethical and legal aspects. Beyond the technical aspect of the invasive home, mechanical ventilation, medical questions also deal with the patient’s symptoms and clinical signs as well as the frequency of complications. Economic questions pertain to the composition of costs and the differences to other ways of homecare concerning costs and quality of care. Questions regarding social aspects consider the health-related quality of life of patients and caregivers. Additionally, the ethical aspects connected to the decision of home mechanical ventilation are viewed. Finally, legal aspects of financing invasive home mechanical ventilation are discussed. Methods: Based on a systematic literature search in 2008 in a total of 31 relevant databases current literature is viewed and selected by means of fixed criteria. Randomized controlled studies, systematic reviews and HTA reports (health technology assessment, clinical studies with patient numbers above ten, health-economic evaluations, primary studies with particular cost analyses and quality-of-life studies related to the research questions are included in the analysis. Results and discussion: Invasive mechanical ventilation may improve symptoms of hypoventilation, as the analysis of the literature shows. An increase in life expectancy is likely, but for ethical reasons it is not confirmed by premium-quality studies. Complications (e. g. pneumonia are rare. Mobile home ventilators are available for the implementation of the ventilation. Their technical performance however, differs regrettably. Studies comparing the economic aspects of ventilation in a hospital to outpatient ventilation, describe home ventilation as a more cost-effective alternative to in-patient care in an intensive care unit, however, more expensive in comparison to a noninvasive (via mask ventilation. Higher expenses arise due to the necessary equipment and the high expenditure of time for the partial 24-hour care of the affected patients through highly qualified personnel. However, none of the studies applies to the German provisionary conditions. The calculated costs strongly depend on national medical fees and wages of caregivers, which barely allows a transmission of the results. The results of quality-of-life studies are mostly qualitative. The patient’s quality of life using mechanical ventilation is predominantly considered well. Caregivers of ventilated patients report positive as well as negative ratings. Regarding the ethical questions, it was researched which aspects of ventilation implementation will have to be considered. From a legal point of view the financing of home ventilation, especially invasive mechanical ventilation, requiring specialised technical nursing is regulated in the code of social law (Sozialgesetzbuch V. The absorption of costs is distributed to different insurance carriers, who often, due to cost pressures within the health care system, insurance carriers, who consider others and not themselves as responsible. Therefore in practice, the necessity to enforce a claim of cost absorption often arises in order to exercise the basic right of free choice of location. Conclusion: Positive effects of the invasive mechanical ventilation (overall survival and symptomatic are highly probable based on the analysed literature, although with a low level of evidence. An establishment of a home ventilation registry and health care research to ascertain valid data to improve outpatient structures is necessary. Gathering specific G

Börger, Sandra

2010-01-01

8

Synaptic dynamics at the neuromuscular junction: mechanisms and models.  

Science.gov (United States)

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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Neuromuscular Exercise Post Partial Medial Meniscectomy : Randomized Controlled Trial  

DEFF Research Database (Denmark)

PURPOSE: To evaluate the effects of a 12-week, home-based, physiotherapist-guided neuromuscular exercise program on the knee adduction moment (an indicator of mediolateral knee load distribution) in people with a medial arthroscopic partial meniscectomy within the past 3-12 months. METHODS: An assessor-blinded, randomised controlled trial including people aged 30-50 years with no to mild pain following medial arthroscopic partial meniscectomy was conducted. Participants were randomly allocated to either a 12-week neuromuscular exercise program that targeted neutral lower limb alignment or a control group with no exercise. The exercise program included eight individual sessions with one of seven physiotherapists in private clinics, together with home exercises. Primary outcomes were the peak external knee adduction moment during normal pace walking and during a one-leg sit-to-stand. Secondary outcomes included additional measures of knee joint load distribution, patient-reported outcomes, maximal knee and hipmuscle strength, and physical function measures. RESULTS: 60 out of 62 randomized participants (97%) completed the trial. There were no significant between-group differences in the change in the peak knee adduction moment during normal pace walking (mean difference (95% CI), 0.22 (-0.11 to 0.55) Nm/BW×HT %, p=0.19), or during one-leg sit-to-stand (-0.01 (-0.33 to 0.31) Nm/BW×HT %, p = 0.95). There were also no significant between-group differences for any of the secondary outcomes. CONCLUSIONS: In patients 3-12 months following a medial arthroscopic partial meniscectomy, a neuromuscular exercise program did not alter the peak knee adduction moment, a key predictor of osteoarthritis structural disease progression. Australia and New Zealand Clinical Trials Registry (#ACTRN12612000542897).

Hall, Michelle; Hinman, Rana S

2014-01-01

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

Directory of Open Access Journals (Sweden)

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

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

Science.gov (United States)

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 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

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

DEFF Research Database (Denmark)

OBJECTIVE: The project aimed to implement neuromuscular training during a full soccer and handball league season and to experimentally analyze the neuromuscular adaptation mechanisms elicited by this training during a standardized sidecutting maneuver known to be associated with non-contact anterior cruciate ligament (ACL) injury. DESIGN: The players were tested before and after 1 season without implementation of the prophylactic training and subsequently before and after a full season with the implementation of prophylactic training. PARTICIPANTS: A total of 12 female elite soccer players and 8 female elite team handball players aged 26 +/- 3 years at the start of the study. INTERVENTION: The subjects participated in a specific neuromuscular training program previously shown to reduce non-contact ACL injury. METHODS: Neuromuscular activity at the knee joint, joint angles at the hip and knee, and ground reaction forces were recorded during a sidecutting maneuver. Neuromuscular activity in the prelanding phase was obtained 10 and 50 ms before foot strike on a force plate and at 10 and 50 ms after foot strike on a force plate. RESULTS: Neuromuscular training markedly increased before activity and landing activity electromyography (EMG) of the semitendinosus (P < 0.05), while quadriceps EMG activity remained unchanged. CONCLUSIONS: Neuromuscular training increased EMG activity for the medial hamstring muscles, thereby decreasing the risk of dynamic valgus. This observed neuromuscular adaptation during sidecutting could potentially reduce the risk for non-contact ACL injury.

Zebis, Mette K; Bencke, Jesper

2008-01-01

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Mechanism of neuromuscular blockade induced by phenthonium, a quaternary derivative of (-)-hyoscyamine, in skeletal muscles.  

Science.gov (United States)

1. The mechanisms underlying the postjunctional blockade induced by phenthonium [N-(4-phenyl) phenacyl 1-hyoscyamine] were investigated in mammalian and amphibian muscles. This muscarinic antagonist was previously shown to enhance specifically the spontaneous acetylcholine (ACh) release at concentrations that blocked neuromuscular transmission. 2. In both rat diaphragm and frog sartorius muscles, phenthonium (Phen, 1-100 microM) depressed the muscle twitches elicited by nerve stimulation (IC50: 23 microM and 5 microM, respectively), and blocked the nerve-evoked muscle action potential. The neuromuscular blockade was not reversed after incubation with neostigmine. 3. Equal concentrations of Phen decreased the rate of rise and prolonged the falling phase of the directly elicited action potential in frog sartorius muscle fibres, indicating that the drug also affects the sodium and potassium conductance. 4. Phen (50 and 100 microM) protected the ACh receptor against alpha-bungarotoxin (BUTX) blockade in the mouse diaphragm allowing recording of endplate potentials and action potentials after 5 h wash with physiological salt solution. 5. Phen (10-100 microM) produced a concentration- and voltage-dependent decrease of the endplate current (e.p.c.), and induced nonlinearity of the current-voltage relationship. At high concentrations Phen also shortened the decay time constant of e.p.c (tau(e.p.c.)) and reduced its voltage sensitivity. 6. At the same range of concentrations, Phen also reduced the initial rate of [125I]-BUTX binding to junctional ACh receptors of the rat diaphragm (apparent dissociation constant = 24 microM), the relationship between the degree of inhibition and antagonist concentration being that expected for a competitive mechanism. 7. It is concluded that Phen affects the electrical excitability of the muscle fibre membrane, and blocks neuromuscular transmission through a mechanism that affects the agonist binding to its recognition site and ionic channel conductance of the nicotinic ACh receptor. PMID:9720800

Souccar, C; Lima-Landman, M T; Ballejo, G; Lapa, A J

1998-07-01

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Neuromuscular control of fundamental frequency and glottal posture at phonation onset  

OpenAIRE

The laryngeal neuromuscular mechanisms for modulating glottal posture and fundamental frequency are of interest in understanding normal laryngeal physiology and treating vocal pathology. The intrinsic laryngeal muscles in an in vivo canine model were electrically activated in a graded fashion to investigate their effects on onset frequency, phonation onset pressure, vocal fold strain, and glottal distance at the vocal processes. Muscle activation plots for these laryngeal parameters were eval...

Chhetri, Dinesh K.; Neubauer, Juergen; Berry, David A.

2012-01-01

15

Center of Mass Acceleration Feedback Control for Standing by Functional Neuromuscular Stimulation – a Simulation Study  

OpenAIRE

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 due to its rapid responsiveness, focal representation of COM dynamics, and ease of measurement. A computational procedure was developed using an anatomically-realistic, three-dimensional, bipedal biomechanica...

Nataraj, Raviraj; Audu, Musa L.; Kirsch, Robert F.; Triolo, Ronald J.

2012-01-01

16

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

OpenAIRE

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 biomecha...

Raviraj Nataraj; Musa L Audu, Phd; Robert F Kirsch, Phd; Ronald J Triolo, Phd

2012-01-01

17

Effects of neuromuscular lags on controlling contact transitions  

OpenAIRE

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

Venkadesan, Madhusudhan; Valero-cuevas, Francisco J.

2009-01-01

18

Neuromuscular control during stepping down in continuous gait in individuals with and without ankle instability.  

Science.gov (United States)

Ankle sprains are a common injury and those affected are at a risk of developing chronic ankle instability (CAI). Complications of an acute sprain include increased risk of re-injury and persistent disability; however, the exact link between ankle sprains and chronic instability has yet to be elucidated. The purpose of this study was to investigate neuromuscular control (including kinematics, kinetics and EMG) during stepping down from a curb, a common yet challenging daily activity, in persons with ankle instability (n = 11), those with a history of ankle sprain without persistent instability, called ankle sprain "copers" (CPRs) (n = 9) and uninjured controls (CTLs) (n = 13). A significant group difference was noted as the CPR group demonstrated increased tibialis anterior activity in both the preparatory (pre-touchdown) and reactive (post-touchdown) phases when compared to healthy and unstable groups (P ankle and this strategy differed from that used by participants with CAI and uninjured CTLs. These findings provide insight into the neuromuscular control strategies of CPRs, which may allow them to more appropriately control ankle stability following sprains. PMID:24499287

Dundas, Mark A; Gutierrez, Gregory M; Pozzi, Federico

2014-01-01

19

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

20

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

OpenAIRE

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

21

A multiobjective design of a patient and anaesthetist-friendly neuromuscular blockade controller.  

Science.gov (United States)

During surgeries (especially in long ones), patients are subject to a substantial amount of drug dosage necessary to achieve the required neuromuscular blockade level. This paper aims at the development of a fuzzy controller that satisfies two important goals: 1) an optimization of the amount of drug (atracurium) required to induce an adequate level of relaxation and 2) a concomitant ability to explain the undertaken control decision at the level of natural language. For instance, statements of the form "Since the difference between the target and the current blockade level is near zero, a small quantity of drug infusion is currently being applied", where "near zero" and "small" are linguistic terms that are represented as fuzzy sets. In this sense, we can regard this controller as a construct that is human friendly and highly interpretable (transparent). To address the two objectives outlined above, we consider the use of a multiobjective evolutionary optimization. How the quality of the control action and the controller interpretability are formalized and captured in this optimization framework is presented. The effectiveness of the approach is demonstrated through a comprehensive suite of experiments involving 100 simulated patients (used for training) and 500 patients (forming the test set), validating the approach for application in the operating theater. PMID:17867359

Fazendeiro, Paulo; Valente de Oliveira, José; Pedrycz, Witold

2007-09-01

22

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

Science.gov (United States)

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. PMID:22773529

Nataraj, Raviraj; Audu, Musa L; Kirsch, Robert F; Triolo, Ronald J

2012-01-01

23

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

Directory of Open Access Journals (Sweden)

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

Raviraj Nataraj

2012-04-01

24

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

OpenAIRE

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

25

Center of Mass Acceleration Feedback Control of Standing Balance by Functional Neuromuscular Stimulation against External Postural Perturbations  

OpenAIRE

This study investigated the use of center of mass (COM) acceleration feedback for improving performance of a functional neuromuscular stimulation (FNS) control system to restore standing function to a subject with complete, thoracic-level spinal cord injury (SCI). The approach for linearly relating changes in muscle stimulation to changes in COM acceleration was verified experimentally and subsequently produced data to create an input-output map driven by sensor feedback. The feedback gains w...

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

2012-01-01

26

Center of Mass Acceleration Feedback Control of Functional Neuromuscular Stimulation for Standing in the Presence of Internal Postural Perturbations  

OpenAIRE

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 (SCI). 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 requi...

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

2012-01-01

27

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

Science.gov (United States)

The purpose of this research was to determine the effects of footwear comfort perception on the gain of the gastrocnemius H-reflex response during single leg balance tasks. Subjects performed single leg balance tasks while wearing aerobic sneakers with two different pairs of shoe insoles that were subjectively rated for comfort using a reliable 150 mm visual analog scale. The primary outcome was the consistency of decreasing the gain of the gastrocnemius H-reflex with increasing balance task complexity as a function of footwear comfort perception. Among the asymptomatic subjects (n = 11), H-reflex gain significantly decreased by 19% and 10% from balancing on a stable surface to an unstable surface for the shoe-brand and replacement insoles, respectively (p disorders (n = 13), H-reflex gain significantly decreased by 10% from balancing on a stable surface to an unstable surface when wearing custom-molded foot orthotics, but H-reflex gain significantly increased by 27% from balancing on a stable surface to an unstable surface when wearing replacement insoles (p footwear comfort perception may negatively impact the attenuation of gastrocnemius H-reflex gain that contributes to the neuromuscular control of challenging balance tasks. PMID:22117882

Burke, Jeanmarie R

2012-04-01

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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  

OpenAIRE

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 con...

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

2008-01-01

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

Science.gov (United States)

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

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

2015-01-01

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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  

Directory of Open Access Journals (Sweden)

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

Directory of Open Access Journals (Sweden)

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

Thalita Duque Martins

2007-02-01

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

Scientific Electronic Library Online (English)

Full Text Available BACKGROUND: Elastic resistance bands (ERB) combined with proprioceptive neuromuscular facilitation (PNF) are often used in resistance muscle training programs, which have potential effects on peripheral muscle strength. However, the effects of the combination of ERB and PNF on respiratory muscle 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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Effects of home-based resistance training and neuromuscular electrical stimulation in knee osteoarthritis: a randomized controlled trial  

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

Bruce-Brand Robert A

2012-07-01

34

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

DEFF Research Database (Denmark)

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

Thorlund, J B; Michalsik, L B

2008-01-01

35

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

Science.gov (United States)

Rolling is a movement pattern seldom used by physical therapists for assessment and intervention with adult clientele with normal neurologic function. Rolling, as an adult motor skill, combines the use of the upper extremities, core, and lower extremities in a coordinated manner to move from one posture to another. Rolling is accomplished from prone to supine and supine to prone, although the method by which it is performed varies among adults. Assessment of rolling for both the ability to complete the task and bilateral symmetry may be beneficial for use with athletes who perform rotationally-biased sports such as golf, throwing, tennis, and twisting sports such as dance, gymnastics, and figure skating. Additionally, when used as intervention techniques, the rolling patterns have the ability to affect dysfunction of the upper quarter, core, and lower quarter. By applying proprioceptive neuromuscular facilitation (PNF) principles, the therapist may assist patients and clients who are unable to complete a rolling pattern. Examples given in the article include distraction/elongation, compression, and manual contacts to facilitate proper rolling. The combined experience of the four authors is used to describe techniques for testing, assessment, and treatment of dysfunction, using case examples that incorporate rolling. The authors assert that therapeutic use of the developmental pattern of rolling with techniques derived from PNF is a hallmark in rehabilitation of patients with neurologic dysfunction, but can be creatively and effectively utilized in musculoskeletal rehabilitation. PMID:21509112

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

2009-05-01

36

Patient-reported perception of difficulty as a clinical indicator of dysfunctional neuromuscular control during the prone hip extension test and active straight leg raise test.  

Science.gov (United States)

Two clinical tests used to assess for neuromuscular control deficits in patients with low back pain (LBP) are the prone hip extension (PHE) test and active straight leg raise (ASLR) test. For these tests, it has been suggested that patients be classified as "positive" if they demonstrate specific "abnormal" lumbopelvic motion patterns. For the ASLR test, the use of patient-reported perception of difficulty is also used to assess neuromuscular control. Thirty participants with LBP and 40 asymptomatic controls took part in this cross-sectional observational study. Participants performed both tests and were classified as "positive" or "negative" based on the presence or absence (respectively) of specific "abnormal" motion patterns. The participants also rated their perceived difficulty in performing the tests using a six-point scale. A two-way analysis of covariance (ANCOVA) was used to examine the effects of group (LBP/control) and examiner classification (positive/negative) on the perceived difficulty scores for each test. The LBP group perceived greater difficulty in performing both tests compared to the control group. Conversely, there was no significant difference in the perceived difficulties of the positive and negative examiner classifications for either test. Additional investigation is required to comment further on the relative usefulness of the perceived difficulty and observable motion patterns during these tests in assessing the neuromuscular control strategies of the lumbopelvic region, and their potential as a diagnostic tool or treatment outcome. PMID:24999072

Bruno, Paul A; Goertzen, Dale A; Millar, David P

2014-12-01

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Neuromuscular blocking agents.  

Science.gov (United States)

Clearly, many aspects of the action of neuromuscular blockers remain poorly understood at the molecular level. In the case of competitive blockers, blockade of EPPs by competitive binding to the ACh receptor site accounts for the most clinically important aspect of blockade. Although train-of-four fade produced by curare and some other competitive agents probably represents a presynaptic action, the molecular mechanisms underlying this effect have not been addressed. Depolarizing blockade is inherently more complicated than competitive blockade. Simple depolarization and inactivation of the mechanism for generation of the action potential probably account for the major clinical effect seen in phase I block. Furthermore, the relative balance between activation of channels and desensitization may also provide a qualitative explanation for phase II block and tachyphylaxis. However, effects that are more likely to be explained by presynaptic actions of depolarizing blockers have also been described, and it is not yet possible to assess quantitatively whether the rates of onset of the different postsynaptic actions can account for most aspects of depolarizing block. This discussion has raised several issues which need to be addressed in future studies. 1. What are the presynaptic effects of cholinergic drugs? Do these drugs act through a specific receptor or, on other ion channels in the terminal membrane, or do they operate by mechanisms distinct from effects on membrane conductance? Can any of the observations be explained by indirect effects mediated through postsynaptic ACh receptors, e.g., K+ release? 2. What are the factors that influence variability in sensitivity to neuromuscular blockers among species, muscles within species, and during development? Many of the potential factors, e.g., differences in safety factor, resting conductances, ACh receptor type, and differences in the presence and absence of presynaptic receptors, have been outlined, but definitive tests of the contribution of any particular mechanisms are lacking. 3. Does modulation of desensitization play a role in any components of neuromuscular blockade? 4. Can trapping of blocking agents in ion channels in some cases account for slowly reversible components of blockade? 5. Can closed-channel block provide an effective mechanism of neuromuscular block? PMID:2848776

Lingle, C J; Steinbach, J H

1988-01-01

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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

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Center of Mass Acceleration Feedback Control of Functional Neuromuscular Stimulation for Standing in the Presence of Internal Postural Perturbations  

Science.gov (United States)

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 (SCI). 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 extremity (UE) 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 two three-dimensional (3-D) accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, COM acceleration feedback control of stimulation improved standing performance by reducing the UE 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. PMID:23299260

Audu, Musa L.; Triolo, Ronald J.

2013-01-01

40

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

Science.gov (United States)

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. PMID:23299260

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

2012-01-01

41

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

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Full Text Available Abstract Background Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have recently undergone a partial medial meniscectomy. Methods/design 62 people aged 30–50 years who have undergone an arthroscopic partial medial meniscectomy within the previous 3 to 12 months will be recruited and randomly assigned to a neuromuscular exercise or control group using concealed allocation. The neuromuscular exercise group will attend 8 supervised exercise sessions with a physiotherapist and will perform 6 exercises at home, at least 3 times per week for 12 weeks. The control group will not receive the neuromuscular training program. Blinded assessment will be performed at baseline and immediately following the 12-week intervention. The primary outcomes are change in the peak external knee adduction moment measured by 3-dimensional analysis during normal paced walking and one-leg rise. Secondary outcomes include the change in peak external knee adduction moment during fast pace walking and one-leg hop and change in the knee adduction moment impulse during walking, one-leg rise and one-leg hop, knee and hip muscle strength, electromyographic muscle activation patterns, objective measures of physical function, as well as self-reported measures of physical function and symptoms and additional biomechanical parameters. Discussion The findings from this trial will provide evidence regarding the effect of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during various tasks in people with a partial medial meniscectomy. If shown to reduce the knee adduction moment, neuromuscular exercise has the potential to prevent the onset of osteoarthritis or slow its progression in those with early disease. Trial Registration Australian New Zealand Clinical Trials Registry reference: ACTRN12612000542897

Hall Michelle

2012-11-01

42

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

43

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

44

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

OpenAIRE

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 benc...

Curtis S To, Phd; Rudi Kobetic, Ms; Thomas C Bulea, Ms; Musa L Audu, Phd; John R Schnellenberger, Ms; Gilles Pinault, Md; Ronald J Triolo, Phd

2011-01-01

45

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

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Osteoarthritis of the knee involving predominantly the medial tibiofemoral compartment is common in older people, giving rise to pain and loss of function. Many people experience progressive worsening of the disease over time, particularly those with varus malalignment and increased medial knee joint load. Therefore, interventions that can reduce excessive medial knee loading may be beneficial in reducing the risk of structural progression. Traditional quadriceps strengthening can improve pain and function in people with knee osteoarthritis but does not appear to reduce medial knee load. A neuromuscular exercise program, emphasising optimal alignment of the trunk and lower limb joints relative to one another, as well as quality of movement performance, while dynamically and functionally strengthening the lower limb muscles, may be able to reduce medial knee load. Such a program may also be superior to traditional quadriceps strengthening with respect to improved pain and physical function because of the functional and dynamic nature. This randomised controlled trial will investigate the effect of a neuromuscular exercise program on medial knee joint loading, pain and function in individuals with medial knee joint osteoarthritis. We hypothesise that the neuromuscular program will reduce medial knee load as well as pain and functional limitations to a greater extent than a traditional quadriceps strengthening program. Methods/Design 100 people with medial knee pain, radiographic medial compartment osteoarthritis and varus malalignment will be recruited and randomly allocated to one of two 12-week exercise programs: quadriceps strengthening or neuromuscular exercise. Each program will involve 14 supervised exercise sessions with a physiotherapist plus four unsupervised sessions per week at home. The primary outcomes are medial knee load during walking (the peak external knee adduction moment from 3D gait analysis, pain, and self-reported physical function measured at baseline and immediately following the program. Secondary outcomes include the external knee adduction moment angular impulse, electromyographic muscle activation patterns, knee and hip muscle strength, balance, functional ability, and quality-of-life. Discussion The findings will help determine whether neuromuscular exercise is superior to traditional quadriceps strengthening regarding effects on knee load, pain and physical function in people with medial knee osteoarthritis and varus malalignment. Trial Registration Australian New Zealand Clinical Trials Registry reference: ACTRN12610000660088

Bennell Kim L

2011-12-01

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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 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

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Quality of Residual Neuromuscular Control and Functional Deficits in Patients with Spinal Cord Injury  

OpenAIRE

Study Design: Prospective cohort study Objective: This study examined the relationship between motor control and clinical function outcomes after spinal cord injury (SCI). Setting: University of Louisville, Louisville, Kentucky, USA. Material: Eleven persons with SCI and 5 non-injured subjects were included in this study. Methods: The American Spinal Injury Association Impairment Scale (AIS) was used to categorize injury level and severity. Multi-muscle, surface EMG (sEMG) record...

AlexanderOvechkin; ToddVitaz; DanielaTerson de Paleville; WilliamBMcKay

2013-01-01

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Experimental study of magnetically controlled transport of neuromuscular blocking agents diadonium and dipyronium in animals  

International Nuclear Information System (INIS)

The possibility of using liposomes containing ferrocolloid for the targeted transport of the muscle relaxants diadonium and dipyronium in cats was studied in this paper. The degree of incorporation of the drugs into magnetically controlled liposomes (MCL) was assessed quantitatively by spectrophotometry in the UV region. To assess the quantitative distribution of MCL in the tissues of the body, 14C-oleic acid incorporated into the MCL bilayer was used. The experiments confirmed that MCL may be used for directing the supply of drugs toward a target organ

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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 posterior (51%; P 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

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Neuromuscular interactions around the knee in children, adults and elderly  

OpenAIRE

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...

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

2014-01-01

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Mechanisms in environmental control  

International Nuclear Information System (INIS)

The theory of implementation provides methods for decentralization of decisions in societies. By using mechanisms (game forms) it is possible (in theory) to implement attractive states in different economic environments. As an example the market mechanisms can implement Pareto-efficient and individual rational allocations in an Arrow-Debreu economic environment without market failures. And even when there exists externalities the market mechanism sometime can be used if it is possible to make a market for the goods not allocated on a market already - examples are marketable emission permits, and deposit refund systems. But environmental problems can often be explained by the existence of other market failures (e.g. asymmetric information), and then the market mechanism do not work properly. And instead of using regulation or traditional economic instruments (subsidies, charges, fees, liability insurance, marketable emission permits, or deposit refund systems) to correct the problems caused by market failures, some other methods can be used to deal with these problems. This paper contains a survey of mechanisms that can be used in environmental control when the problems are caused by the existence of public goods, externalities, asymmetric information, and indivisible goods in the economy. By examples it will be demonstrated how the Clarke-Groves mechanism, the Cournot-Lindahl mechanism, and other mechanisms can be used to solve specific environmental problems. This ise specific environmental problems. This is only theory and examples, but a recent field study have used the Cournot-Lindahl mechanism to solve the problem of lake liming in Sweden. So this subject may be of some interests for environmental policy in the future. (au) 23 refs

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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

53

Control rod drive mechanism  

International Nuclear Information System (INIS)

A ball screw shaft rotatably inserted and disposed at the inner side of a housing for control rod drive mechanisms and a ball nut which is screw-coupled to the ball screw shaft and moves along the ball screw shaft are made of Ni-Cr-Fe-Mo-Nb alloys. When a control rod is inserted into a reactor pressure vessel, a detector is actuated by a magnetic force of a movable magnet, and the movement of the control rod is detected. Although the ball nut and the ball screw shaft are situated near the detector and they are made of metal components connected to the magnet, they are not magnetized and do not cause misoperation of the position detector by applying undesired effects on the detector. (T.M.)

54

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.)

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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

56

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

DEFF Research Database (Denmark)

The benefits of exercise in mild and moderate knee or hip osteoarthritis (OA) are apparent, but the evidence in severe OA is less clear. We recently reported that neuromuscular training was well tolerated and feasible in patients with severe primary hip or knee OA. The aims of this controlled before-and-after study were to compare baseline status to an age-matched population-based reference group and to examine the effects of neuromuscular training on patient-reported outcomes and physical function in patients with severe primary OA of the hip or knee.

Ageberg, Eva; Nilsdotter, Anna

2013-01-01

58

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

59

Implementation of a guideline for the treatment of pain, sedation, agitation and neuromuscular blockade in the mechanically ventilated adult patient in the emergency department  

Directory of Open Access Journals (Sweden)

Full Text Available Kristin E White1, Paul M Szumita1, Nicki Gilboy2, Hillary A Keenan3, Christian Arbelaez21Department of Pharmacy Services, 2Department of Emergency Medicine, 3Center for Clinical Investigation, Brigham and Women's Hospital, Boston, MA, USAPurpose: When emergency department (ED overcrowding includes admitted mechanically ventilated (MV critically-ill patients without an open intensive care unit (ICU bed, emergency providers must deliver ICU level care in the ED. Implementing standardized hospital based clinical guidelines may help providers achieve uniform care standards for assessing and managing pain and sedation for the MV patient.Objective: This paper is a description of a hospital performance improvement project that was implemented in the ED. The objective of this study was to measure the degree of adoption of a hospital-wide clinical guideline for the management of pain, sedation and neuromuscular blockade in MV patients into clinical practice in the ED.Methods: A retrospective analysis was performed for all mechanically ventilated patients who were admitted from ED to an Intensive Care Unit (ICU. Patient charts were reviewed before (December 2005 and after the implementation of the guideline (June, August, and December 2006. Data was collected and analyzed for the ED visit only and no ICU data was used. The primary outcome was the degree of adoption of the guideline by emergency providers into their daily clinical practice.Results: A convenience sample of 170 adult MV patients who were admitted to the ICU during the preselected time period was analyzed. There were no demographic differences between groups of patients observed during each month interval, age (P = 0.34, gender (P = 0.40, race (P = 0.14, and Hispanic ethnicity (P = 0.84. Overall, there was an increase in the provider use of propofol (P < 0.01, RASS sedation scale (P < 0.01, and a decrease in the use of a paralytic agent (P < 0.01.Conclusion: There was partial adoption of a guideline into their clinical practice by emergency providers in a busy urban emergency department. Across the 12-month implementation period, there was improvement in the assessment of and use of analgesia and sedation for MV patients.Keywords: clinical guideline, critical care, ICU, emergency department, sedation, pain, neuromuscular blocker

White KE

2011-04-01

60

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

61

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

62

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

LENUS (Irish Health Repository)

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

O'Driscoll, Jeremiah

2011-06-09

63

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

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Modified Newton-Raphson method to tune feedback gains of control system for standing by functional neuromuscular stimulation following spinal cord injury  

Science.gov (United States)

BACKGROUND Functional neuromuscular stimulation (FNS) can restore standing capabilities following spinal cord injury. Feedback control of these systems can optimize performance by reducing the required upper extremity support. However, tuning these control systems can be intensive and clinically inconvenient. OBJECTIVE This case study investigated a clinical method to efficiently tune feedback gains for a control system utilizing feedback of total body center of mass acceleration to modulate stimulation levels to targeted paralyzed musculature of the lower extremities and trunk. METHODS Gains for this control system were tuned to minimize the stabilization loading by one arm against internal postural perturbations volitionally-generated during manipulation of an object using the other arm. An algorithm based on a modified form of the Newton-Raphson method was employed to find the optimal feedback gains with lower subject effort than that to determine the original tuning curves. RESULTS This method accurately (<6.2% error) approximated the optimal gains with 70% fewer manipulations by the subject. CONCLUSIONS These results suggest that optimal feedback gains for the specific FNS control system can be determined systematically with considerably less effort than heuristic gain tuning. This demonstrates the potential for devising simple, convenient methods for effective system re-tuning during clinical usage. PMID:25684981

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

2015-01-01

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

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

2014-09-01

66

Control rod drive mechanism  

International Nuclear Information System (INIS)

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

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

DEFF Research Database (Denmark)

Generalised Joint Hypermobility (GJH) is considered an intrinsic risk factor for knee injuries. Knee neuromuscular control during landing may be altered in GJH due to reduced passive stability. The aim was to identify differences in knee neuromuscular control during landing of the Single-Leg-Hop-for-Distance test (SLHD) in 25 children with GJH compared to 29 children without GJH (controls), all 10-15years. Inclusion criteria for GJH: Beighton score?5/9 and minimum one hypermobile knee. EMG was recorded from the quadriceps, the hamstring and the calf muscles, presented relative to Maximum Voluntary Electrical activity (MVE). There was no difference in jump length between groups. Before landing, GJH had 33% lower Semitendinosus, but 32% higher Gastrocnemius Medialis activity and 39% higher co contraction of the lateral knee muscles, than controls. After landing, GJH had 36% lower Semitendinosus activity than controls, all significant findings. Although the groups performed equally in SLHD, GJH had a Gastrocnemius Medialis dominated neuromuscular strategy before landing, plausibly caused by reduced Semitendinosus activity. Reduced Semitendinosus activity was seen in GJH after landing, but with no compensatory Gastrocnemius Medialis activity. Reduced pre and post-activation of the Semitendinosus may present a risk factor for traumatic knee injuries as ACL ruptures in GJH with knee hypermobility.

Junge, Tina; Wedderkopp, Niels

2015-01-01

68

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.)

69

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

70

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

71

Therapy for neuromuscular disorders.  

Science.gov (United States)

Research into therapeutic approaches for both recessive and dominant neuromuscular disorders has made great progress over the past few years. In the field of gene therapy, antisense-mediated exon skipping is being applied to bypass deleterious mutations in the dystrophin gene and restore dystrophin expression in animal models of muscular dystrophy. Approaches for the dominant genetic muscle diseases have turned toward elimination of the mutant gene product with anti-sense oligonucleotide therapy and RNA interference techniques. Refinements of adeno-associated viral vectors and strategies for their delivery are also leading towards future clinical trials. The discovery of new, multipotent cell lineages, some of which possess the ability to successfully engraft muscle following vascular delivery, presents exciting prospects for the field of stem cell therapy. These discoveries represent steady progress towards the development of effective therapies for a wide range of neuromuscular disorders. PMID:19411172

Arnett, Andrea L H; Chamberlain, Joel R; Chamberlain, Jeffrey S

2009-06-01

72

Effects of Neuromuscular Electrical Stimulation Combined with Exercises versus an Exercise Program on the Pain and the Function in Patients with Knee Osteoarthritis: A Randomized Controlled Trial  

Science.gov (United States)

Objectives. To investigate the effect of 8 weeks of NMES + Ex (neuromuscular electrical stimulation combined with exercises) on pain and functional improvement in patients with knee osteoarthritis (OA) compared to exercise (Ex) alone. Design. Randomized controlled trial. Setting. A specialty outpatient clinic. Participants. Patients (N = 100; women = 86, men = 14; age range, 50–75 years) with knee OA. Interventions. Participants were randomly assigned to NMES + Ex or Ex group. Outcome Measures. Numerical Rating Scale 0 to 10 (NRS) and the Timed Up and Go (TUG) test were the primary outcomes. The secondary outcomes used were the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results. Following the interventions, a statistically significant improvement in both groups was observed in all outcomes assessed. For the comparison between the groups, no statistically significant difference was found between the NMES + Ex and the Ex groups in NRS (P = 0.52), TUG test (P = 0.12), and aspects of WOMAC: pain (P = 0.26), function (P = 0.23), and stiffness (P = 0.63). Conclusion. The addition of NMES to exercise did not improve the outcomes assessed in knee OA patients. This study was registered at the Australian Clinical Trials Registry (ACTRN012607000357459). PMID:24151589

Mizusaki Imoto, Aline; Peccin, Stella; Gomes da Silva, Kelson Nonato; de Paiva Teixeira, Lucas Emmanuel Pedro; Abrahão, Marcelo Ismael; Fernandes Moça Trevisani, Virgínia

2013-01-01

73

Urgencias en patología neuromuscular Emergencies in neuromuscular pathology  

Directory of Open Access Journals (Sweden)

Full Text Available La debilidad muscular aguda (DMA es el síntoma predominante de las urgencias neuromusculares, especialmente si afecta a la musculatura respiratoria u orofaríngea. La DMA es un síndrome plurietiológico y con distintos niveles lesionales en la unidad motora. Dentro del amplio grupo de enfermedades neuromusculares, las que con mayor frecuencia provocan DMA e insuficiencia respiratoria son el síndrome de Guillain-Barré (SGB y la miastenia gravis (MG. El SGB constituye la causa más frecuente de parálisis flácida aguda; puede ocasionar fallo respiratorio en un tercio de los casos precisando ventilación mecánica. El diagnóstico preciso de este síndrome permitirá iniciar tratamiento inmunomodulador, que ha demostrado que modifica el curso de la enfermedad. Además, la valoración clínica de los pacientes y el conocimiento de sencillos tests neurofisiológicos y de función respiratoria guiarán la decisión de ventilación mecánica evitando la intubación de urgencia. La urgencia más frecuente que ocasiona la MG es la crisis miasténica, definida por el deterioro en la función bulbar con insuficiencia respiratoria aguda y riesgo de parada respiratoria. Ocurre en un 15-20% de pacientes miasténicos y puede desencadenarse por múltiples factores. Además del diagnóstico preciso de la crisis es importante la supresión de los factores desencadenantes y medidas de soporte ventilatorio. Entre las medidas farmacológicas son la plasmaféresis y las inmunoglobulinas intravenosas los instrumentos más útiles en la actualidad; estos tratamientos no sustituyen la vigilancia intensiva y el reconocimiento de los signos inminentes de fallo respiratorio que implican soporte ventilatorio invasivo o no invasivo.Acute muscle weakness (AMW is the predominant symptom of neuromuscular emergencies, especially if it affects the respiratory or oropharyngeal musculature . AMW is a multi-etiological syndrome, with different lesion levels in the motor unit. Within the broad group of neuromuscular diseases, those that most frequently provoke AMW and respiratory failure are Guillain-Barré syndrome (GBS and myasthenia gravis (MG. GBS is the most frequent cause of acute flaccid paralysis; it can cause respiratory failure in a third of cases, making mechanical ventilation necessary. Accurate diagnosis of this syndrome enables immunomodulatory treatment to be started, which has been shown to modify the course of the disease. Besides, clinical evaluation of the patients and knowledge of the simple tests of neurophysiology and respiratory function will guide the decision on mechanical ventilation, avoiding emergency intubation. The most frequent emergency caused by MG is myasthenic crisis, defined by the deterioration in the bulbar function with acute respiratory insufficiency and risk of respiratory stoppage. This occurs in 15-20% of myasthenic patients and can be triggered by numerous factors. Besides early identification of the crisis, it is important to suppress the triggering factors and to provide measure of ventilatory support. Amongst the pharmacological measures, the most useful instruments at present are plasmapheresis and intravenous immunoglobulins; these treatments do not cancel the need for intensive vigilance and of checking for imminent signs of respiratory failure that will involve invasive or non-invasive ventilatory support.

T. Ayuso

2008-01-01

74

[Mechanisms which control the peripheral nerve excitability].  

Science.gov (United States)

Peripheral nerve excitability is currently tested via the strength/duration curves, and by measuring the minimal intensity level (rheobase) of an efficient stimulation, and the minimal duration (chronaxy) for a stimulus equal to two times the minimal threshold. New "threshold tracking techniques" were recently described (Bostock et al., 1991), which afford an automatic evaluation of nerve excitabilty. These methods investigate the mechanisms responsible for the membrane potential: passive ionic currents, activity of ionic pumps like the Na-K-ATPase; and the dynamic behaviour of large conductance sodium, potassium, and calcium channels, responsible for the generation and conduction of action potentials. Results obtained must however be evaluated taking into account the following items: stimulation is delivered through the skin and subcutaneous tissue; a nerve trunk is explored, and not a single fiber; most often the response is recorded over a muscle, hence through neuromuscular synapses. PMID:15244155

Guihéneuc, P

2004-01-01

75

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

OpenAIRE

Abstract Background Neuromuscular electrostimulation has become a promising issue in cardiovascular rehabilitation. However there are few articles published in the literature regarding neuromuscular electrostimulation in patients with heart failure during hospital stay. Methods This is a randomized controlled pilot trial that aimed to investigate the effect of neuromuscular electrostimulation in the walked distance by the six-minute walking test in 30 patients admitted to ward for heart failu...

de Araújo Carlos José Soares; Gonçalves Fernanda Souza; Bittencourt Hugo Souza; dos Santos Noélia Gonçalves; Junior Sérgio Vitor Mecca; Neves Júlio Leal Bandeira; Fernandes André Maurício Souza; Junior Roque Aras; dos Reis FranciscoJoséFariasBorges; Guimarães Armênio Costa; Junior ErenaldodeSouzaRodrigues; Carvalho Vitor Oliveira

2012-01-01

76

Emerging considerations in the reversal of neuromuscular blockade and residual block  

Directory of Open Access Journals (Sweden)

Full Text Available Incomplete recovery following reversal of neuromuscular blockade can present as a clinical problem in surgical patients. Emerging pharmacologic solutions may prevent such adverse outcomes in the future. We briefly review two methods of pharmacologic reversal of neuromuscular blockade. Both methods of reversal are effective. However the early studies of the new compound, sugammadex has been shown to achieve a more rapid, stable reversal of steroidal based neuromuscular blocking agents compared to neostigmine. Due to the novel mechanism of action of this agent, sugammadex has been demonstrated to be effective even when administered during profound neuromuscular block, without evidence of recurarization.

CHRISTOPHER J. JANKOWSKI

2008-04-01

77

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

78

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 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

79

Neuromuscular block by antibiotics: polymyxin B.  

Science.gov (United States)

Characteristics of neuromuscular block produced by polymyxin B (PXB) were examined in 12 anesthetized cats, using sciatic nervetibialis anticus muscle preparations. The ED50 was 6.7 (+/- 1.4, SD) PXB base/kg body weight. The ED95 was 10.8 (+/- 2.4) mg/kg. Spontaneous recovery from 25 percent of control to 75 percent of control required 72 (+/- 16) minutes. During a 50 percent block, train-of-four twitches elicited at 2 Hz faded with a train-of-four ratio of 0.42 (+/- 0.13), but the tetanus did not fade. Edrophonium Cl, neostigmine methylsulfate, and pyridostigmine Br at sub-clinical dosages weakly antagonized the block but enhanced the block at anti-curare dosages. All 3 cholinesterase inhibitors were short acting, lasting 10 to 15 minutes, and noncumulative on repeated injection. The potency ratio was approximately 20:10:1 in the order of edrophonium, neostigmine, and pyridostigmine on a weight-for-weight basis. Calcium partially antagonized the block. The authors conclude that neuromuscular blocks produced by various antibiotics differ from each other and from that produced by other groups of neuromuscular blocking agents, including curare. PMID:194505

Lee, C; Chen, D; Nagel, E L

1977-01-01

80

Urgencias en patología neuromuscular / Emergencies in neuromuscular pathology  

Scientific Electronic Library Online (English)

Full Text Available La debilidad muscular aguda (DMA) es el síntoma predominante de las urgencias neuromusculares, especialmente si afecta a la musculatura respiratoria u orofaríngea. La DMA es un síndrome plurietiológico y con distintos niveles lesionales en la unidad motora. Dentro del amplio grupo de enfermedades ne [...] uromusculares, las que con mayor frecuencia provocan DMA e insuficiencia respiratoria son el síndrome de Guillain-Barré (SGB) y la miastenia gravis (MG). El SGB constituye la causa más frecuente de parálisis flácida aguda; puede ocasionar fallo respiratorio en un tercio de los casos precisando ventilación mecánica. El diagnóstico preciso de este síndrome permitirá iniciar tratamiento inmunomodulador, que ha demostrado que modifica el curso de la enfermedad. Además, la valoración clínica de los pacientes y el conocimiento de sencillos tests neurofisiológicos y de función respiratoria guiarán la decisión de ventilación mecánica evitando la intubación de urgencia. La urgencia más frecuente que ocasiona la MG es la crisis miasténica, definida por el deterioro en la función bulbar con insuficiencia respiratoria aguda y riesgo de parada respiratoria. Ocurre en un 15-20% de pacientes miasténicos y puede desencadenarse por múltiples factores. Además del diagnóstico preciso de la crisis es importante la supresión de los factores desencadenantes y medidas de soporte ventilatorio. Entre las medidas farmacológicas son la plasmaféresis y las inmunoglobulinas intravenosas los instrumentos más útiles en la actualidad; estos tratamientos no sustituyen la vigilancia intensiva y el reconocimiento de los signos inminentes de fallo respiratorio que implican soporte ventilatorio invasivo o no invasivo. Abstract in english Acute muscle weakness (AMW) is the predominant symptom of neuromuscular emergencies, especially if it affects the respiratory or oropharyngeal musculature . AMW is a multi-etiological syndrome, with different lesion levels in the motor unit. Within the broad group of neuromuscular diseases, those th [...] at most frequently provoke AMW and respiratory failure are Guillain-Barré syndrome (GBS) and myasthenia gravis (MG). GBS is the most frequent cause of acute flaccid paralysis; it can cause respiratory failure in a third of cases, making mechanical ventilation necessary. Accurate diagnosis of this syndrome enables immunomodulatory treatment to be started, which has been shown to modify the course of the disease. Besides, clinical evaluation of the patients and knowledge of the simple tests of neurophysiology and respiratory function will guide the decision on mechanical ventilation, avoiding emergency intubation. The most frequent emergency caused by MG is myasthenic crisis, defined by the deterioration in the bulbar function with acute respiratory insufficiency and risk of respiratory stoppage. This occurs in 15-20% of myasthenic patients and can be triggered by numerous factors. Besides early identification of the crisis, it is important to suppress the triggering factors and to provide measure of ventilatory support. Amongst the pharmacological measures, the most useful instruments at present are plasmapheresis and intravenous immunoglobulins; these treatments do not cancel the need for intensive vigilance and of checking for imminent signs of respiratory failure that will involve invasive or non-invasive ventilatory support.

T., Ayuso; I., Jericó.

81

LRRK2 Kinase Regulates Synaptic Morphology through Distinct Substrates at the Presynaptic and Postsynaptic Compartments of the Drosophila Neuromuscular Junction  

OpenAIRE

Mutations in leucine-rich repeat kinase 2 (LRRK2) are linked to familial as well as sporadic forms of Parkinson’s disease (PD), a neurodegenerative disease characterized by dysfunction and degeneration of dopaminergic and other types of neurons. The molecular and cellular mechanisms underlying LRRK2 action remain poorly defined. Here, we show that LRRK2 controls synaptic morphogenesis at the Drosophila neuromuscular junction. Loss of Drosophila LRRK2 results in synaptic overgrowth, whereas ...

Lee, Seongsoo; Liu, Hsin-ping; Lin, Wei-yong; Guo, Huifu; Lu, Bingwei

2010-01-01

82

Neuromuscular adaptation to actual and simulated weightlessness  

Science.gov (United States)

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

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

1994-01-01

83

Cambios en el control neuromuscular de seis músculos de miembro inferior durante CMJ máximos realizados con fatiga / Changes in neuromuscular control of six lower limb muscles during maximum CMJ with fatigue / Mudanças no controle neuromuscular de seis músculos de membro inferior durante a execução de CMJ máximos com fadiga  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Spanish Abstract in portuguese Há diferentes opiniões a respeito da existência de mudanças no controle muscular quando os saltos com contramovimento (CMJ) são realizados em condição de fadiga. Este artigo avalia se as atividades e a sequência temporal de ativação de seis músculos do membro inferior durante o CMJ mudam devido à fa [...] diga. O nível de atividade variou principalmente nos músculos biarticulares. Os tempos dos picos de atividade elétrica sugerem a existência de grupos de ação muscular e mudanças na sequência de ativação dentro de cada grupo. Foi possível estabelecer a existência de um padrão geral de controle muscular durante o apoio nos CMJ, com ajustes do nível e tempo de ativação que dependem do período temporal analisado e o músculo considerado. Abstract in spanish Hay diferentes opiniones respecto a si existen cambios en el control muscular cuando saltos con contramovimiento (CMJ) son realizados en condición de fatiga. Este trabajo evalúa si la actividad y la secuencia temporal de activación de seis músculos de miembro inferior durante CMJ cambian por causa d [...] e la fatiga. El nivel de actividad varió principalmente en los músculos biarticulares. Los tiempos de los picos de actividad eléctrica sugieren la existencia de grupos de acción muscular, si bien ocurren cambios en la secuencia de activación dentro de cada grupo. Fue posible establecer que existe un patrón general de control muscular durante el apoyo en los CMJ, con ajustes del nivel y tiempo de activación que dependen del periodo temporal analizado y el músculo considerado. Abstract in english Previous studies have not reached an agreement regarding changes in muscle control when countermovement jump (CMJ) tests are performed in fatigue conditions. This paper evaluates whether the activity and time activation sequence of six lower limb muscles change, due to fatigue during CMJ. We found t [...] hat the activity level varied mainly in the bi-articular muscles. Also, the temporal characteristics of the electrical activity peak suggested that muscles actioned as coordinated groups, although there were changes in the activation sequence within each group. Finally, it was possible to establish a general muscle control pattern during CMJ stance phase. However, adjustments were made on activation time and level that depended on the time period analyzed and the muscle considered.

Gabriel, Fábrica; Paula, González Rodríguez; Jefferson Fagundes, Loss.

2013-06-01

84

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

Science.gov (United States)

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

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

2014-03-01

85

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

Science.gov (United States)

While healthy aging is associated with physiological changes that can impair control of trunk motion, few studies examine how spinal muscle responses change with increasing age. This study examined whether older (over 65 years) compared to younger (20-45 years) adults had higher overall amplitude and altered temporal recruitment patterns of trunk musculature when performing a functional transfer task. Surface electromyograms from twelve bilateral trunk muscle (24) sites were analyzed using principal component analysis, extracting amplitude and temporal features (PCs) from electromyographic waveforms. Two PCs explained 96% of the waveform variance. Three factor ANOVA models tested main effects (group, muscle and reach) and interactions for PC scores. Significant (p<.0125) group interactions were found for all PC scores. Post hoc analysis revealed that relative to younger adults, older adults recruited higher agonist and antagonistic activity, demonstrated continuous activation levels in specific muscle sites despite changing external moments, and had altered temporal synergies within abdominal and back musculature. In summary both older and younger adults recruit highly organized activation patterns in response to changing external moments. Differences in temporal trunk musculature recruitment patterns suggest that older adults experience different dynamic spinal stiffness and loading compared to younger adults during a functional lifting task. PMID:25457424

Quirk, D Adam; Hubley-Kozey, Cheryl L

2014-12-01

86

Control mechanisms for ecological-economic systems  

CERN Document Server

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

Burkov, Vladimir N; Shchepkin, Alexander V

2015-01-01

87

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

88

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  

Science.gov (United States)

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 PMID:22152427

2011-01-01

89

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

90

Induction of giant miniature end-plate potentials during blockade of neuromuscular transmission by textilotoxin.  

Science.gov (United States)

The present study investigated the action of textilotoxin, isolated from the venom of the Australian common brown snake Pseudonaja textilis, on neuromuscular transmission in isolated toad nerve-muscle preparations. Initial muscle twitch tension experiments revealed a triphasic pattern of changes in muscle tension and a irreversible binding action of textilotoxin (10 micrograms/ml) similar to other snake beta-neurotoxins. This was characterised by an initial depression of twitch tension, followed by a period of enhanced tension, eventually leading to a reduction in tension to complete neuromuscular blockade. These actions on muscle tension were investigated further by assessing the action of textilotoxin on end-plate potential amplitude (EPP). This revealed a similar triphasic alteration of the nerve-evoked release of acetylcholine from the motor nerve terminal. These actions on acetylcholine release were confirmed to be of a presynaptic origin since the modal amplitude of miniature end-plate potentials (MEPPs) was not reduced and in twitch tension experiments the muscle still contracted in response to direct muscle stimulation when nerve-evoked release was completely blocked. Interestingly dramatic effects were observed on the spontaneous release of acetylcholine, including an marked increase in MEPP frequency, a skewing of the MEPP amplitude frequency histogram to the right, and a resultant increase in the number of 'giant' MEPPs. These results indicate that textilotoxin causes a presynaptic blockade of neuromuscular transmission involving a disruption of the regulatory mechanism that controls acetylcholine release. PMID:7477429

Wilson, H I; Nicholson, G M; Tyler, M I; Howden, M E

1995-07-01

91

Mechanical control systems on Lie algebroids  

OpenAIRE

This paper considers control systems defined on Lie algebroids. After deriving basic controllability tests for general control systems, we specialize our discussion to the class of mechanical control systems on Lie algebroids. This class of systems includes mechanical systems subject to holonomic and nonholonomic constraints, mechanical systems with symmetry and mechanical systems evolving on semidirect products. We introduce the notions of linear connection, symmetric produ...

Cortes, Jorge; Martinez, Eduardo

2004-01-01

92

Control of a mechanical gripper with a fuzzy controller  

International Nuclear Information System (INIS)

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

93

Neuromuscular dysfunction following eccentric exercise.  

Science.gov (United States)

This study examined the effects of exercise-induced muscle damage on tremor and proprioception components of neuromuscular function. Six male and six female volunteers (aged 18-30 yr) performed 50 maximal eccentric muscle actions using the forearm flexors of the nondominant arm. Forearm flexor tremor and perception of voluntary force and joint position were monitored to assess changes in neuromuscular function. Data were analyzed using REANOVA. Serum creatine kinase activity increased from a baseline value of 68 +/- 13 IU.l-1 to 2849 +/- 852 IU.l-1 5 d after exercise (P Muscle soreness peaked 3 d postexercise (P damage-inducing eccentric exercise suggest significant impairment of neuromuscular function. PMID:7476064

Saxton, J M; Clarkson, P M; James, R; Miles, M; Westerfer, M; Clark, S; Donnelly, A E

1995-08-01

94

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

95

Protein defects in neuromuscular diseases  

Scientific Electronic Library Online (English)

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.

M., Vainzof; M., Zatz.

2003-05-01

96

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

97

Neuromuscular Activity and Knee Kinematics in Adolescents with Patellofemoral Pain  

DEFF Research Database (Denmark)

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

Rathleff, Michael Skovdal; Samani, Afshin

2013-01-01

98

Estrogen influences on neuromuscular function in postmenopausal women.  

Science.gov (United States)

Exposure to ovarian sex steroids during different life phases has long-term effects on women's health and wellbeing. Menopause is characterized by rapid decline in ovarian sex steroids already during mid-life, between the ages of 46 and 52. Due to the menopause-related hormonal changes, women in most western countries live more than one-third of their lives in postmenopausal status. The role of ovarian steroids on neuromuscular function in middle-aged and older women has been investigated since the 1980s with increasing volume of research during the last decades. This review considers how different components of the neuromuscular system may be influenced by estrogens and so affects neuromuscular function in postmenopausal women. The main focus is on muscle strength and power, which are closely associated with mobility and functional capacity among older populations. In the end of the review, we summarize recent findings on the underlying biological mechanisms in skeletal muscle that could explain the association between hormone replacement therapy and neuromuscular function among postmenopausal women. PMID:25359124

Sipilä, S; Finni, T; Kovanen, V

2015-03-01

99

Autoimmune Neuromuscular Disorders in Childhood  

OpenAIRE

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

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

2011-01-01

100

Neuromuscular Disease Descriptions  

Science.gov (United States)

... addressing any underlying respiratory or heart problems. Peripheral motor neuron diseases (involving muscle-controlling nerve cells of the ... vary. Often associated with diabetes and heart disease. Motor neuron diseases (involving nerve cells in the spinal cord) ...

101

Alteration of neuromuscular function in squash.  

Science.gov (United States)

The alteration in neuromuscular function of knee extensor muscles was characterised after a squash match in 10 trained players. Maximal voluntary contraction (MVC) and surface EMG activity of vastus lateralis (VL) and vastus medialis (VM) muscles were measured before and immediately after a 1-h squash match. M-wave and twitch contractile properties were analysed following single stimuli. MVC declined (280.5+/-46.8 vs. 233.6+/-35.4 Nm, -16%; Psquash match play caused peripheral fatigue by impairing excitation-contraction coupling, whereas sarcolemmal excitability seems well preserved. Our results also emphasise the role of central activation failure as a possible mechanism contributing to the torque loss observed in knee extensors. Physical conditioners should consider these effects when defining their training programs for squash players. PMID:19231287

Girard, Olivier; Micallef, Jean-Paul; Noual, Julien; Millet, Grégoire P

2010-01-01

102

14 CFR 29.691 - Autorotation control mechanism.  

Science.gov (United States)

...AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow rapid entry into...

2010-01-01

103

14 CFR 27.691 - Autorotation control mechanism.  

Science.gov (United States)

...AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow rapid entry into...

2010-01-01

104

Mechanical engineers' handbook, design, instrumentation, and controls  

CERN Document Server

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

Kutz, Myer

2015-01-01

105

Computed tomography of skeletal muscles in neuromuscular disease  

Energy Technology Data Exchange (ETDEWEB)

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

Rodiek, S.O.; Kuether, G.

1985-06-01

106

Informational and Neuromuscular Contributions to Anchoring in Rhythmic Wrist Cycling  

OpenAIRE

Continuous rhythmic movements are often geared toward particular points in the movement cycle, as evidenced by a local reduction in trajectory variability. These so-called anchor points provide a window into motor control, since changes in the degree of anchoring may reveal how informational and/or neuromuscular properties are exploited in the organization of rhythmic movements. The present experiment examined the relative contributions of informational timing (metronome beeps) and neuromuscu...

Roerdink, Melvyn; Ridderikhoff, Arne; Peper, C. E.; Beek, Peter J.

2012-01-01

107

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

Science.gov (United States)

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

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

2015-01-01

108

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

109

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

110

Development and plasticity of the Drosophila larval neuromuscular junction  

Science.gov (United States)

The Drosophila larval neuromuscular system is relatively simple, containing only 32 motor neurons in each abdominal hemisegment, and its neuromuscular junctions (NMJs) are large, individually specified, and easy to visualize and record from. NMJ synapses exhibit developmental and functional plasticity while displaying stereotyped connectivity. Drosophila Type I NMJ synapses are glutamatergic, while the vertebrate NMJ uses acetylcholine as its primary neurotransmitter. The larval NMJ synapses use ionotropic glutamate receptors (GluRs) that are homologous to AMPA-type glutamate receptors in the mammalian brain, and they have postsynaptic scaffolds that resemble those found in mammalian postsynaptic densities. These features make the Drosophila neuromuscular system an excellent genetic model for the study of excitatory synapses in the mammalian central nervous system. The first section of the review presents an overview of NMJ development. The second section describes genes that regulate NMJ development, including: 1) genes that positively and negatively regulate growth of the NMJ; 2) genes required for maintenance of NMJ bouton structure; 3) genes that modulate neuronal activity and alter NMJ growth; 4) genes involved in trans-synaptic signaling at the NMJ. The third section describes genes that regulate acute plasticity, focusing on translational regulatory mechanisms. Since this review is intended for a developmental biology audience, it does not cover NMJ electrophysiology in detail, and does not review genes for which mutations produce only electrophysiological but no structural phenotypes. PMID:24014452

Menon, Kaushiki P.; Carrillo, Robert A.; Zinn, Kai

2013-01-01

111

[Macro EMG in neuromuscular diseases].  

Science.gov (United States)

The aim of this study is the introducing of macro-emg method as electrophysiological test used in diagnosis of neuromuscular diseases. The macro motor unit potentials (macro MUPs) obtained by recording macroelectrode (modified single-fibre electrode) represents temporal and spatial summation of individual single fiber action potentials belonging to whole motor unit territory--so the uptake area is larger for macroelectrode than for the concentric electrode, commonly used in emg routine work, when central main complex is generated only from less than 15 muscle fibers [10, 12, 13]. Additional information obtained by macro-emg method is spatial organisation of muscle fibers within the motor unit, so-called fiber density (F.D) In our study macro-emg examinations were performed in 20 healthy subjects, aged 21-55, without signs and symptoms of neuromuscular disorders. Macro MUPs were recorded using special programme for macro-emg and performed on electromyograph Counterpoint. 37 muscles (20 BB and 17 RF) were examined, and median values of amplitude, area of macro MUPs and F.D. in healthy subjects of different age were analyzed. Mean values of median for amplitude and area of macro MUPs in BB and RF muscles show respectively--148 microV, 382 microV x ms, and 319 microV, 763 microV x ms. Parameters of macro MUPs obtained in healthy subjects were compared to results obtained in 10 patients with myopathy and lower motor neuron lesion. Our results have confirmed the value of macro-emg method for investigating of the pathophysiological changes in motor units in neurogenic disorders, in myopathy the study should be continued. PMID:10463226

Szmidt-Sa?kowska, E; Rowi?ska-Marci?ska, K; Kope?, A; Wawro, A

1998-01-01

112

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

Scientific Electronic Library Online (English)

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

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

2012-12-01

113

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

Directory of Open Access Journals (Sweden)

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

Joaquín Fabregat López

2012-12-01

114

Pregnancy and Childbirth with Neuromuscular Disease  

Science.gov (United States)

... as additional information not found in the print magazine. Contents include: Caution, Preparation and Teamwork Lead to the Best Pregnancy Outcomes in Women with Neuromuscular Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Disease-Specific Complications (chart) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

115

Adiposity is associated with improved neuromuscular reaction time.  

Science.gov (United States)

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

Grantham, James; Henneberg, Maciej

2014-11-01

116

Tracheal intubation without neuromuscular block in children  

OpenAIRE

Endotracheal intubation has been performed during the administration of Propofol anaesthesia without neuromuscular blockade. In the study, we have assessed tracheal intubating conditions and haemodynamic responses in children aged 4 to12 years by using combination of either Fentanyl and Propofol; or Propofol and a neuromuscular blocker, suxamethonium. Intubating conditions were assessed on a 1-4 scale based on ease of laryngoscopy, position of vocal cords, degree of coughing and jaw relaxatio...

Shaikh, Safiya I.; Bellagali, Vijayalaxmi P.

2010-01-01

117

Neuromuscular Electrical Stimulation for Skeletal Muscle Function  

OpenAIRE

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

118

Sugammadex: A revolutionary drug in neuromuscular pharmacology  

OpenAIRE

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

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

2013-01-01

119

Sugammadex: A revolutionary drug in neuromuscular pharmacology  

Science.gov (United States)

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

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

2013-01-01

120

PICU EXTUBATION FAILURE: THE ROLE OF NEUROMUSCULAR DISORDERS  

Directory of Open Access Journals (Sweden)

Full Text Available ObjectiveNeuromuscular disorders (diseases of the motor unit, can cause respiratory problems such as impaired cough reflex, chest deformity, recurrent pneumonia and acute respiratory failure; these are the worst most common complications of these diseases and the leading cause of death in such patients (1, 2. Their management hence, very often, entails admission to the Pediatric Intensive Care Unit (PICU (3,4 and during this phase, endotracheal intubation is almost always necessary, to maintain the patency of airways and to apply Positive Pressure Ventilation (PPV. However, endotracheal intubation is always temporary, and its success or failure depends on the timely decision of its termination to restore the normal respiration or to avoid the risk of recurring respiratory failure (5, 6. We designed this study to evaluate the role of neuromuscular disorders in causing extubation failure as compared to that of other risk factors.Materials & MethodsIn an analytical cross-sectional study, the risk factors of reintubation and duration of mechanical ventilation in two groups of 30 patients each, was compared, the first successful extubation and the second with extubation failure.ResultsNeuromuscular disorders (including Spinal Muscular Atrophy, Guillain- Barre' Syndrome, Congenital Myopathies and Muscular Dystrophies were the main underlying diseases in extubation-failure group (P= 0.0002. Hypercapnia (PaCO2>50mmHg was shown to be the most common cause of both the first intubation (P=0.001 and reintubation (P=0.004 in the group of patients who failed extubation. The mean duration of intubation and mechanical ventilation was longer in patients with neuromuscular disorders who had extubation failure (P= 0.01.ConclusionThis study showed that, as underlying problems, neuromuscular disorders are the most common causes of prolonged intubation which defeat weaning from the ventilator and result in reintubation by inducing hypercapnia. Therefore the weaning process needs to be done gradually in these patients, and in conjunction with supportive measures, such as close observation for at least for 72 hours following extubation to monitor any possibility of recurrence of hypercapnic respiratory failure.

N. Billan MD,

2007-02-01

121

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

122

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

Science.gov (United States)

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. PMID:21938668

To, Curtis S; Kobetic, Rudi; Bulea, Thomas C; Audu, Musa L; Schnellenberger, John R; Pinault, Gilles; Triolo, Ronald J

2011-01-01

123

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

124

Replacement means for control rod drive mechanism  

International Nuclear Information System (INIS)

Object: To permit assembling and removal operation of a control rod drive mechanism to be carried out speedily and properly irrespective of the degree of skill of the operating personnel. Structure: When removing a control rod drive mechanism (CRD) a service platform and a frame body are operated for bringing a CRD lift guide frame to a position below the CRD to be removed. Then, a CRD receptacle is placed at the lower end of the CRD, and water is drained from the CRD. Subsequently, a chain is driven by a drive means in a direction which lowers the receptacle, and only the CRD is lowered along the CRD lift guide frame. Thereafter, the CRD is secured at its upper portion by a support means, and the CRD lift guide frame is lowered by a lift jack to thereby permit revolution of the CRD, The CRD lift frame after revolution is lifted and then removed to the outside. (Kamimura, M.)

125

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

Science.gov (United States)

...Usability § 1193.41 Input, control, and mechanical functions. Input, control, and mechanical functions...that does not require user auditory perception. (e) Operable...not require user fine motor control or simultaneous...

2010-07-01

126

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

127

Development of Mechanical Water Level Controller  

OpenAIRE

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, ...

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

2012-01-01

128

Eletroestimulação neuromuscular na reabilitação da disfagia orofaríngea Neuromuscular electrical stimulation in the rehabilitation of oropharyngeal dysphagia  

Directory of Open Access Journals (Sweden)

Full Text Available A reabilitação da disfagia orofaríngea ganhou um novo instrumento terapêutico, a eletroestimulação neuromuscular (EENM, sendo que os mais renomados pesquisadores têm estudado a indicação e os resultados desta abordagem. O objetivo deste trabalho foi apresentar revisão bibliográfica sobre a aplicabilidade da EENM na reabilitação da disfagia orofaríngea. Realizou-se amplo levantamento bibliográfico em bases de dados, englobando as duas últimas décadas de pesquisa na área. Este artigo de revisão mostrou que ainda não há consenso sobre o uso da EENM na reabilitação da disfagia. Constatou-se que a maioria dos trabalhos descreveu o uso da EENM de forma isolada, não relatou as técnicas fonoaudiológicas associadas à eletroterapia e utilizou amostras heterogêneas que agrupavam disfagias orofaríngeas mecânicas e neurogênicas. Somente recentemente programas específicos têm sido delineados e testados em populações mais homogêneas.The rehabilitation of oropharyngeal dysphagia has a new therapeutic tool, the neuromuscular electrical stimulation (NMES, and the most renowned researchers have been studying the applicability and the results of this approach. The aim of this study was to present a literature review regarding the applicability of NMES in the rehabilitation of oropharyngeal dysphagia. An extensive literature review was carried out, considering the last two decades of research in the area. The review showed that there is still no consensus on the use of NMES in the rehabilitation of dysphagia. It was found that most studies described the use of NMES in isolation, did not describe the techniques associated with speech-language therapy associated to electrotherapy, and used heterogeneous samples that clustered mechanical and neurogenic oropharyngeal dysphagia. Only recently specific programs have been designed and tested in more homogeneous populations.

Bruno Tavares de Lima Guimarães

2010-12-01

129

Eletroestimulação neuromuscular na reabilitação da disfagia orofaríngea / Neuromuscular electrical stimulation in the rehabilitation of oropharyngeal dysphagia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A reabilitação da disfagia orofaríngea ganhou um novo instrumento terapêutico, a eletroestimulação neuromuscular (EENM), sendo que os mais renomados pesquisadores têm estudado a indicação e os resultados desta abordagem. O objetivo deste trabalho foi apresentar revisão bibliográfica sobre a aplicabi [...] lidade da EENM na reabilitação da disfagia orofaríngea. Realizou-se amplo levantamento bibliográfico em bases de dados, englobando as duas últimas décadas de pesquisa na área. Este artigo de revisão mostrou que ainda não há consenso sobre o uso da EENM na reabilitação da disfagia. Constatou-se que a maioria dos trabalhos descreveu o uso da EENM de forma isolada, não relatou as técnicas fonoaudiológicas associadas à eletroterapia e utilizou amostras heterogêneas que agrupavam disfagias orofaríngeas mecânicas e neurogênicas. Somente recentemente programas específicos têm sido delineados e testados em populações mais homogêneas. Abstract in english The rehabilitation of oropharyngeal dysphagia has a new therapeutic tool, the neuromuscular electrical stimulation (NMES), and the most renowned researchers have been studying the applicability and the results of this approach. The aim of this study was to present a literature review regarding the a [...] pplicability of NMES in the rehabilitation of oropharyngeal dysphagia. An extensive literature review was carried out, considering the last two decades of research in the area. The review showed that there is still no consensus on the use of NMES in the rehabilitation of dysphagia. It was found that most studies described the use of NMES in isolation, did not describe the techniques associated with speech-language therapy associated to electrotherapy, and used heterogeneous samples that clustered mechanical and neurogenic oropharyngeal dysphagia. Only recently specific programs have been designed and tested in more homogeneous populations.

Bruno Tavares de Lima, Guimarães; Ana Maria, Furkim; Roberta Gonçalves da, Silva.

2010-12-01

130

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

131

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

132

Neuromuscular Adaptations to Reduced Use  

Science.gov (United States)

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

Ploutz-Snyder, Lori

2009-01-01

133

Fluorescence control through multiple interference mechanisms  

CERN Document Server

We discuss the spontaneous emission from a coherently prepared and microwave driven doublet of potentially closely spaced excited states to a common ground level. Multiple interference mechanisms are identified which may lead to fluorescence inhibition in well-separated regions of the spectrum or act jointly in cancelling the spontaneous emission. In addition to phase independent quantum interferences due to combined absorptions and emissions of driving field photons, we distinguish two competing phase dependent interference mechanisms as means of controlling the fluorescence. The indistinguishable quantum paths may involve the spontaneous emission from the same state of the doublet, originating from the two different components of the initial coherent superposition. Alternatively the paths involve a different spontaneous photon from each of two decaying states, necessarily with the same polarization. This makes these photons indistinguishable in principle within the uncertainty of the two decay rates. The ph...

Paspalakis, E; Knight, P L

1998-01-01

134

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

135

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

136

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

137

Gain control mechanisms in spinal motoneurons  

Directory of Open Access Journals (Sweden)

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

Michael David Johnson

2014-07-01

138

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

139

Neuromuscular control of the point to point and oscillatory movements of a sagittal arm with the actor-critic reinforcement learning method.  

Science.gov (United States)

In this study, we have used a single link system with a pair of muscles that are excited with alpha and gamma signals to achieve both point to point and oscillatory movements with variable amplitude and frequency.The system is highly nonlinear in all its physical and physiological attributes. The major physiological characteristics of this system are simultaneous activation of a pair of nonlinear muscle-like-actuators for control purposes, existence of nonlinear spindle-like sensors and Golgi tendon organ-like sensor, actions of gravity and external loading. Transmission delays are included in the afferent and efferent neural paths to account for a more accurate representation of the reflex loops.A reinforcement learning method with an actor-critic (AC) architecture instead of middle and low level of central nervous system (CNS), is used to track a desired trajectory. The actor in this structure is a two layer feedforward neural network and the critic is a model of the cerebellum. The critic is trained by state-action-reward-state-action (SARSA) method. The critic will train the actor by supervisory learning based on the prior experiences. Simulation studies of oscillatory movements based on the proposed algorithm demonstrate excellent tracking capability and after 280 epochs the RMS error for position and velocity profiles were 0.02, 0.04 rad and rad/s, respectively. PMID:16154874

Golkhou, Vahid; Parnianpour, Mohamad; Lucas, Caro

2005-04-01

140

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 (H(2)O(2)) on metal surfaces. However, there are literature studies in which H(2)O(2) could not be detected in the bulk solution. This is most likely because H(2)O(2) 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 H(2)O(2) can reduce cell growth on metal surfaces. It was found that H(2)O(2) was produced near 316L SS surfaces when a negative potential was applied. The H(2)O(2) concentration increased towards the surface, while the dissolved oxygen decreased when the SS surface was polarized to -600 mV(Ag/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 H(2)O(2) in the bulk solution, it was found that the surface concentration of H(2)O(2) was able to prevent biofilm growth. PMID:22827804

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

2012-01-01

141

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

142

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

143

Effects of a short proprioceptive neuromuscular facilitation stretching bout on quadriceps neuromuscular function, flexibility, and vertical jump performance.  

Science.gov (United States)

The inclusion of relatively long bouts of stretching (repeated static stretches of ?30 seconds) in the warm-up is usually associated with a drop in muscle performance. The purpose of this study was to assess the effect of a novel self-administered proprioceptive neuromuscular facilitation (PNF) paradigm with short periods of stretching and contraction on quadriceps neuromuscular function, vertical jump performance, and articular range of motion (ROM). Twelve healthy men (age: 27.7 ± 7.3 years, height: 178.4 ± 10.4 cm, weight: 73.8 ± 16.9 kg) volunteered to participate in a PNF session and a control session separated by 2-7 days. The PNF stretching lasted 2 minutes and consisted of 4 sets of 5-second isometric hamstring contraction immediately followed by 5 seconds of passive static stretch of the quadriceps immediately followed by 5 seconds isometric quadriceps contraction for each leg. For the control session, the participants were asked to walk at a comfortable speed for 2 minutes. Active ROM of knee flexion, vertical jump performance, and quadriceps neuromuscular function were tested before, immediately after, and 15 minutes after the intervention. The PNF stretching procedure did not affect ROM, squat jump, and countermovement jump performances. Accordingly, we did not observe any change in maximal voluntary contraction force, voluntary activation level, M-wave and twitch contractile properties that could be attributed to PNF stretching. The present self-administered PNF stretching of the quadriceps with short (5-second) stretches is not recommended before sports where flexibility is mandatory for performance. PMID:22505131

Place, Nicolas; Blum, Yannick; Armand, Stéphane; Maffiuletti, Nicola A; Behm, David G

2013-02-01

144

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 | Languages: English, 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

Maria Cristina Simões de, Almeida.

2004-12-01

145

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

Directory of Open Access Journals (Sweden)

Full Text Available JUSTIFICATIVA E OBJETIVOS: Dados estatísticos referentes ao uso de bloqueadores neuromusculares no Brasil são desconhecidos. Este trabalho se propõe a análise estatística desse tópico. MÉTODO: Foram compiladas 831 respostas de um questionário preenchido em parte por anestesiologistas presentes ao 48º Congresso Brasileiro de Anestesiologia em Recife, 2001 e em parte via Internet, por anestesiologistas cujos endereços eletrônicos constam na página da Sociedade Brasileira de Anestesiologia (www.sba.com.br. Foram analisados os seguintes dados: tempo de contato com a especialidade, região onde atuam os anestesiologistas, uso de bloqueadores neuromusculares (BNM em ordem de preferência, indicações do uso de succinilcolina, uso do monitor da transmissão neuromuscular, critérios para se considerar o paciente descurarizado, uso de neostigmina, forma de administração dos BNM e descrição de complicações observadas. RESULTADOS: A maioria dos anestesiologistas em questão exerce a profissão há mais de 11 anos e o maior número de respostas foi proveniente da região sudeste do Brasil. O BNM mais empregado é o atracúrio, seguido de pancurônio e succinilcolina. A succinilcolina é mais empregada na indução rápida e em crianças (80% e 25% respectivamente. Monitores da transmissão neuromuscular, 53% dos anestesiologistas nunca usam, e como critério de recuperação, 92% consideram o paciente descurarizado mediante sinais clínicos. Em 45% das vezes os profissionais empregam a neostigmina de forma rotineira, e 94% administra os BNM sob forma de bolus. Cerca de 30% registra ter havido complicação decorrente do uso de BNM. As complicações mais apontadas foram o bloqueio prolongado, o broncoespasmo grave e a curarização residual. CONCLUSÕES: O atracúrio é o bloqueador neuromuscular mais empregado no Brasil, há percentual alto de uso da succinilcolina em situações não emergenciais, o uso de monitores da transmissão neuromuscular é raro, e, como um corolário, um percentual significativo de uso de critérios eminentemente clínicos para considerar o paciente descurarizado. Registrou-se que, cerca de 30% dos anestesiologistas teve algum tipo de complicação decorrente do uso desses fármacos.JUSTIFICATIVA Y OBJETIVOS: Dados estadísticos referentes al uso de bloqueadores neuromusculares en Brasil son desconocidos. Este trabajo se propone el análisis estadístico de ese tópico. MÉTODO: Fueron compiladas 831 respuestas de un cuestionario llenado en parte por anestesiologistas presentes al 48º Congreso Brasileño de Anestesiologia en la ciudad de Recife, 2001 y en parte vía Internet, por anestesiologistas cuyas direcciones electrónicas constan en la página de la Sociedad Brasileña de Anestesiologia (www.sba.com.br. Fueron analizados los siguientes datos: tiempo de contacto con la especialidad, región donde actúan los anestesiologistas, uso de bloqueadores neuromusculares (BNM en orden de preferencia, indicaciones del uso de succinilcolina, uso del monitor de transmisión neuromuscular, criterios para considerar el paciente descurarizado, uso de neostigmina, forma de administración de los BNM y descripción de complicaciones observadas. RESULTADOS: La mayoría de los anestesiologistas en cuestión ejerce la profesión hace más de 11 años y el mayor número de respuestas fue proveniente de la región sudeste de Brasil. El BNM más empleado es el atracúrio, seguido de pancurónio y succinilcolina. La succinilcolina es más empleada en la inducción rápida y en niños (80% y 25% respectivamente. Monitores de la transmisión neuromuscular, 53% de los anestesiologistas nunca usan, y como criterio de recuperación, 92% consideran el paciente descurarizado mediante señales clínicas. En un 45% de las veces los profesionales emplean la neostigmina de forma rutinaria, y 94% administra los BNM bajo forma de bolus. Cerca del 30% registra que tuvieron complicación consecuente del uso de BNM. Las complicaciones más apuntadas fueron el bloqueo prolongado, el broncoespasmo gr

Maria Cristina Simões de Almeida

2004-12-01

146

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

Science.gov (United States)

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

Holroyd, Jean; Guthrie, Donald

1986-01-01

147

Control rod drive mechanism vent valve assembly  

International Nuclear Information System (INIS)

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

148

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

149

Reversión del bloqueo neuromuscular inducido por vecuronio: sugammadex o neostigmina / Reversal of vecuronium-induced neuromuscular blockade: sugammadex vs. neostigmine  

Scientific Electronic Library Online (English)

Full Text Available Introducción: se han descrito diferencias entre la reversión de los bloqueantes neuromusculares con sugammadex y neostigmina. La mayoría concuerda que los resultados con sugammadex son superiores. Objetivos: comparar la capacidad del sugammadex y la neostigmina para revertir el bloqueo neuromuscular [...] con vecuronio. Métodos: se realizó un estudio de casos y controles, para evaluar la capacidad del recobro muscular con vecuronio, tras la reversión con sugammadex y neostigmina. Se evaluó el recobro muscular por exploración clínica. Resultados: se estudiaron un total de 405 pacientes, al Grupo S, correspondieron 135 pacientes y al Grupo N 270. El tiempo medio de duración de la intervención quirúrgica, fue para el grupo S de 32,21±1,2 min y para el Grupo N de 33,16 ±1,2 min. El promedio de tiempo de la reversión en el grupo S fue de 2.2 minutos y en el grupo N de 14.4 min. La calidad de la recuperación, en ambos grupos fue buena, no obstante las diferencias observadas en la frecuencia de los revertidos con sugammadex, resultó estadísticamente significativa (p = 0.00001). Las complicaciones fueron mas frecuentes en el grupo N. Conclusiones: se corroboró la capacidad del sugammadex para revertir el bloqueo neuromuscular con vecuronio. El tiempo de reversión del bloqueo fue 6,54 veces más prolongado con neostigmina. La calidad de la recuperación fue 1.34 veces mejor con de sugammmadex. Las reacciones adversas fueron 11,02 veces mas frecuentes con neostigmina que con sugammadex. Abstract in english Introduction: studies are available about the differences between reversal of neuromuscular blockers with sugammadex and neostigmine. Most studies agree that results are better when sugammadex is used. Objectives: compare the capacity of sugammadex and neostigmine to revert vecuronium-induced neurom [...] uscular blockade. Methods: a case-control study was conducted to evaluate neuromuscular recovery with vecuronium after reversal with sugammadex and neostigmine. Muscular recovery was evaluated by clinical examination. Results: a total 405 patients were studied. Group S was composed of 135 patients and Group N of 270. Mean surgical duration was 32.21±1.2 min for Group S and 33.16 ±1.2 min for Group N. Average reversal time was 2.2 min in Group S and 14.4 min in Group N. The quality of recovery was good in both groups. However, the frequency differences found in patients reverted with sugammadex were statistically significant (p = 0.00001). Complications were more frequent in Group N. Conclusions: the capacity of sugammadex to revert vecuronium-induced neuromuscular blockade was confirmed. Reversal time was 6.54 longer with neostigmine. The quality of recovery was 1.34 times better with sugammadex. Adverse reactions were 11.02 times more frequent with neostigmine than with sugammadex.

Migdel G, Abreu Darias; Idoris, Cordero Escobar; Gisela, Pérez Martinez.

2014-12-01

150

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

Directory of Open Access Journals (Sweden)

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

Patricia Fernández

2010-12-01

151

Decreased muscle endurance associated with diabetic neuropathy may be attributed partially to neuromuscular transmission failure.  

Science.gov (United States)

Diabetic polyneuropathy (DPN) can cause muscle atrophy, weakness, contractile slowing, and neuromuscular transmission instability. Our objective was to assess the response of the impaired neuromuscular system of DPN in humans when stressed with a sustained maximal voluntary contraction (MVC). Baseline MVC and evoked dorsiflexor contractile properties were assessed in DPN patients (n = 10) and controls (n = 10). Surface electromyography was used to record tibialis anterior evoked maximal compound muscle action potentials (CMAPs) and neuromuscular activity during MVCs. Participants performed a sustained isometric dorsiflexion MVC for which task termination was determined by the inability to sustain ?60% MVC torque. The fatigue protocol was immediately followed by a maximal twitch, with additional maximal twitches and MVCs assessed at 30 s and 2 min postfatigue. DPN patients fatigued ?21% more quickly than controls (P 0.05). Twitch torque and CMAP amplitude recovered to baseline 30 s postfatigue. Additionally, at 30 s postfatigue, both groups had similar (?10%) reductions in MVC torque relative to baseline, and MVC strength recovered by 2 min postfatigue. We conclude DPN patients possess less endurance than controls, and neuromuscular transmission failure may contribute to this greater fatigability. PMID:25663671

Allen, Matti D; Kimpinski, Kurt; Doherty, Timothy J; Rice, Charles L

2015-04-15

152

Neuromuscular compartments of cat lateral gastrocnemius produce different torques about the ankle joint.  

Science.gov (United States)

The primary purpose of this study was to establish whether the neuromuscular compartments of cat lateral gastrocnemius produce different mechanical actions on the skeletal system, by determining the contributions made by these compartments to the torques produced about the ankle joint. It was postulated that neuromuscular compartments might represent output elements of the spinal circuits. If so, they should produce unique mechanical actions. Isometric torques about the center of the ankle joint produced by the neuromuscular compartments of the cat lateral gastrocnemius were measured with a multiaxis force-moment sensor connected to the plantar surface of the foot. Individual compartment torques were elicited by activation of the primary compartment branches of the lateral gastrocnemius nerve. The magnitude of the individual torque components, and thus of the resultant torque, was significantly different between compartments. In three of the four lateral gastrocnemius compartments, significantly different torque trajectories were noted. The results, together with those from previous studies demonstrating that compartments can be activated in a task-dependent manner, suggest that neuromuscular compartments represent anatomical substrates that can be used by the nervous system for regulating movement. PMID:10529506

Carrasco, D I; Lawrence, J; English, A W

1999-10-01

153

Neuromuscular function in patients with Subacromial Impingement Syndrome and clinical assessment of scapular kinematics  

DEFF Research Database (Denmark)

Neuromuscular function in patients with Subacromial Impingement Syndrome and clinical assessment of scapular kinematics Larsen CM1, Juul-Kristensen B1,2 Holtermann A3, Lund H1,2, Søgaard K1 1University of Southern Denmark, Institute of Sports Science and Clinical Biomechanics, DK 2Institute of Occupational Therapy, Bergen University College, Bergen, Norway 3National Research Centre for the Working Environment, Copenhagen, DK E-mail: cmlarsen@health.sdu.dk AIMS: The aims were to understand potential mechanisms for impairment in the neuromuscular function of the scapular stabilisers in a general patient sample with SIS, and to assess the clinimetric properties of clinical assessment methods of scapular kinematics as important aspects for optimising effect measures of treatment in order to improve clinical guidelines in this area. METHODS: Scapular muscle activity was examined, 1) during a voluntary arm movement task and 2) selective activation tasks during sessions with and without on-line biofeedback, in a general population consisting of 16 SIS patients and 15 controls (No-SIS). Furthermore, 3) a systematic review was conducted of all available clinical scapular assessment methods and their associated clinimetric results, and the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist was used to critically assess the quality of the involved studies for each measurement property. RESULTS: 1) In spite of a general tendency for higher scapular muscle activity among SIS patients, between-group differences were not significant, either in activity level, ratio of activation between muscles or in the time of activity onset of the muscles, 2) Using the defined criteria of: (i) a selective activation above 12% of maximum activation during which other muscle parts were below 1.5% activity or (ii) an activation ratio above 95% of the total activity of all muscles, significantly fewer SIS subjects than No-SIS subjects achieved selective activation of individual scapular muscle compartments without on-line biofeedback of muscle activity from each muscle compartment of the trapezius muscle, 3) On the basis of 46 included articles, a total of 55 names of clinical assessment methods were identified. Thirty-one of the studies included in the quality assessment of the reliability and validity domains were classified as ‘fair’ (55%) to ‘poor’ (45%), with only one study being rated as ‘good’. Few of the assessment methods in the included studies with ‘fair’ or ‘good’ measurement property ratings demonstrated acceptable results for reliability and validity. Responsiveness was not investigated. CONCLUSION: 1) No between-group differences of SIS and No-SIS subjects in neuromuscular activity of scapular stabilising muscles were observed, 2) and when provided with visual EMG feedback, the SIS group performed equally well as the No-SIS group, However, when assessing the neuromuscular function with and without the use of biofeedback, the findings show that without biofeedback, the SIS group had alower scapular muscle control, 3) When addressing the possibility for measuring scapular kinematics clinically, the findings show a substantially larger number of clinical assessment methods for scapular position and function than previously reported. None of the included clinical assessment methods had been examined for all three domains: reliability, validity (diagnostic accuracy), as well as responsiveness. Based on these results, the current findings question the generalisability of current rehabilitation guidelines to the general population with SIS, however, SIS patients may benefit from biofeedback training. Lastly, these results indicate that very few clinical assessment methods have sufficient clinimetric properties that can be recommended for clinical use.

Larsen, Camilla Marie; Lund, Hans

154

Interacciones farmacológicas con el uso de bloqueantes neuromusculares / Drug interactions with the use of neuromuscular blockers  

Scientific Electronic Library Online (English)

Full Text Available Introducción: la interacción medicamentosa es la capacidad que tiene un fármaco de alterar los efectos farmacológicos de otro que se administre simultáneamente. Objetivo: realizar una actualización sobre la interacción farmacológica de los bloqueantes neuromusculares, con fármacos de uso frecuente. [...] Desarrollo: los bloqueadores neuromusculares, se utilizan para relajar la musculatura estriada, garantizar la intubación traqueal, la ventilación y producir un plano quirúrgico suficiente. Muchos medicamentos interactúan con ellos y con frecuencia potencian el efecto bloqueante muscular. Esto resulta de importancia clínica en el caso de antibióticos, anestésicos inhalatorios, litio y ciclosporina. Se puede producir dificultad en la reversión del bloqueo con los bloqueadores de los canales de calcio y la polimixina. Otros como la fenitoína, carbamazepina y litio pueden provocar resistencia a estos fármacos. Existen compuestos que tienen la capacidad de producir relajación muscular por su propia acción, de forma aditiva o sinérgica. En algunas situaciones dichas interacciones pueden ser beneficiosas, como en el caso de los agentes inhalados que cursan con buena relajación muscular y disminuyen los requerimientos de las dosis de bloqueantes neuromusculares; pero en la mayoría de los casos las interacciones son peligrosas. Conclusiones: aunque el anestesiólogo moderno tiene suficientes conocimientos teóricos sobre interacciones medicamentosas, debe tener presenta las que pueden producir los bloqueantes neuromusculares, pues pueden inducir un bloqueo neuromuscular impredecible en la práctica diaria. Abstract in english Introduction: drug interaction is the capacity of a drug to alter the pharmacological effects of another one being administered simultaneously. Objective: carry out an update of the interaction of neuromuscular blockers with frequently used drugs. Results: neuromuscular blockers are used to relax th [...] e striated muscle, permit tracheal intubation and ventilation, and create sufficient surgical plane. Many drugs interact with them, and they frequently enhance the muscular blocking effect. The process is clinically important in the case of antibiotics, inhaled anesthetics, lithium and cyclosporin. Difficulty in blockade reversal may arise when calcium channel blockers and polymyxin are administered. Other drugs, such as phenytoin, carbamazepine and lithium, may cause resistance to these medications. There are compounds which may cause muscular relaxation due to their own action or in an additive or synergic manner. Some such interactions may be beneficial, as is the case with inhaled agents, which produce good muscular relaxation and lower the dose requirements of neuromuscular blockers. But in most cases interactions are dangerous. Conclusions: even though modern anesthesiologists have sufficient theoretical knowledge about drug interactions, they should bear in mind those produced by neuromuscular blockers, for they may induce unpredictable neuromuscular blockade in daily practice.

Idoris, Cordero Escobar.

2014-12-01

155

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

Directory of Open Access Journals (Sweden)

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

156

Analysis of anticholinesterase-induced neuromuscular transmission failure.  

Science.gov (United States)

To define the underlying mechanism of neuromuscular transmission failure induced by anticholinesterases, we simultaneously performed surface recordings of compound muscle action potentials (CMAPs) and intracellular recordings of miniature end-plate potentials (MEPPs), miniature end-plate current (MEPCs), and end-plate potential (EPPs) in rat diaphragms exposed in vitro to 1 x 10(-4) to 2 x 10(-2) mmol/L neostigmine methylsulfate. At low concentrations of neostigmine, repetitive stimulation of the phrenic nerve resulted in decrement followed by complete recuperation of CMAP amplitudes. This bimodal pattern was associated with maximal end-plate depolarization at the beginning of the stimulation period, increased MEPP amplitudes, and prolonged time constants of MEPC decays. Higher concentrations of neostigmine resulted in a unimodal decline of amplitudes of CMAPs and EPPS, reduced MEPP amplitudes, and a double exponential time course of MEPC decays. These results indicate that low concentrations of anticholinesterases impaired neuromuscular transmission by producing transient depolarization of the end-plate region. Higher concentrations induced desensitization and direct blockade of the end-plate receptor channel, probably in its open conformation. PMID:8390609

Maselli, R A; Leung, C

1993-05-01

157

Neuromuscular effects of G93A-SOD1 expression in zebrafish  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Amyotrophic lateral sclerosis (ALS is a fatal disorder involving the degeneration and loss of motor neurons. The mechanisms of motor neuron loss in ALS are unknown and there are no effective treatments. Defects in the distal axon and at the neuromuscular junction are early events in the disease course, and zebrafish provide a promising in vivo system to examine cellular mechanisms and treatments for these events in ALS pathogenesis. Results We demonstrate that transient genetic manipulation of zebrafish to express G93A-SOD1, a mutation associated with familial ALS, results in early defects in motor neuron outgrowth and axonal branching. This is consistent with previous reports on motor neuron axonal defects associated with familial ALS genes following knockdown or mutant protein overexpression. We also demonstrate that upregulation of growth factor signaling is capable of rescuing these early defects, validating the potential of the model for therapeutic discovery. We generated stable transgenic zebrafish lines expressing G93A-SOD1 to further characterize the consequences of G93A-SOD1 expression on neuromuscular pathology and disease progression. Behavioral monitoring reveals evidence of motor dysfunction and decreased activity in transgenic ALS zebrafish. Examination of neuromuscular and neuronal pathology throughout the disease course reveals a loss of neuromuscular junctions and alterations in motor neuron innervations patterns with disease progression. Finally, motor neuron cell loss is evident later in the disease. Conclusions This sequence of events reflects the stepwise mechanisms of degeneration in ALS, and provides a novel model for mechanistic discovery and therapeutic development for neuromuscular degeneration in ALS.

Sakowski Stacey A

2012-08-01

158

Autoregulation of neuromuscular transmission by nerve terminals. Annual report, 1 July 1983-1 July 1984  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate three mechanisms through which acetycholine (ACh) release may be modulated prejunctionally at the motor nerve terminal of skeletal muscle: (1) prejunctional cholinoceptor regulation of ACh release, (2) modulation of ACh release through preconditioning patterns of nerve stimulation, and (3) precursor control of ACh release. Neuromuscular transmission has been assessed in the vascular perfused rat phrenic nerve-diaphragm preparation (VPRH) by measuring the release of ACh directly by radioenzymatic assay or by chemiluminescence assay, and indirectly by intracellular recordings and by force of contradiction (FC) measurements. Additional experiments have been done on rat sciatic nerve in order to examine the axonal transport of nicotinic binding sites. The mouse hemidiahragm preparation has been used to study antidromic activity (backfiring) in the phrenic nerve in the presence of an anticholinesterase agent. The data resulting from the project support the concept that the nerve terminal possesses local mechanism for modulating ACh release. Attempts have been made to understand the normal function of these mechanisms and then to explore their activity under demanding physological conditions, drug exposure, and in the presence of acetylcholinesterase (AChE) inhibitors.

Bierkamper, G.G.

1984-09-01

159

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

160

Fuzzy Adaptive Sliding Mode Control of Large Erecting Mechanism  

OpenAIRE

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

161

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Languages: English, Portuguese, Spanish Abstract in portuguese 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 anticoline [...] sterásicos. 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. Abstract in spanish 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. Abstract in english BACKGROUND AND OBJECTIVES: Neuromuscular blockers (N

Cássio Campelo de, Menezes; Lilian Akemi Moore, Peceguini; Enis Donizetti, Silva; Claudia Marquez, Simões.

2012-08-01

162

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  

Directory of Open Access Journals (Sweden)

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

163

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...

164

Robust Position Control of Electro-mechanical Systems  

OpenAIRE

In this work, the robust position control scheme is proposed for the electro-mechanical system using the disturbance observer and backstepping control method. To the external unknown load of the electro-mechanical system, the nonlinear disturbance observer is given to estimate the external unknown load. Combining the output of the developed nonlinear disturbance observer with backstepping technology, the robust position control scheme is proposed for the electro-mechanical system. The stabili...

Rong Mei; Mou Chen

2013-01-01

165

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.

166

Controlling mechanisms of Thwaites Glacier, West Antarctica  

Science.gov (United States)

Ice shelves play a major role in the stability of fast flowing ice streams in Antarctica, by exerting buttressing on inland ice and controlling the discharge of ice into the ocean. However, the mechanisms at work remain poorly understood and interactions between floating and grounded ice need to be better characterized in order to estimate the impact of climate change on the ice sheets. Thwaites glacier, in West Antarctica, features a small and heavily fractured ice shelf that provides limited back stress pressure on inland ice but is pinned on the eastern part on a prominent ridge. Thwaites glacier has maintained a consistently high velocity and negative mass balance for at least 20 years. Recent observations show a widening of its fast flowing area as well as a sustained acceleration since 2006 and a rapid retreat of its grounding line in the center of the glacier. The objective of this work is to characterize the dynamic response of Thwaites glacier to changes in its floating tongue on decadal to centennial time scales. To achieve this objective, we rely on high resolution ice flow modeling and grounding line dynamics using the Ice Sheet System Model (ISSM). We will focus on the complex interplay between the main floating tongue of Thwaites Glacier and its eastern, slow moving ice shelf, which is pinned down by an ice rumple. The speed of the eastern ice shelf is strongly affected by the coupling with the main floating ice tongue, which results in significant fluctuations in speed of the eastern ice shelf the formation of ice shelf cracks at the grounding line during acceleration phases. Our results show that ice rigidity at the junction between the eastern and western part of the shelf controls the dynamic regime of the ice shelf and suggest that Thwaites Glacier is likely to undergo substantial changes in the coming decades. This work was performed at the California Institute of Technology's Jet Propulsion Laboratory and the University of California Irvine under a contract with the National Aeronautics and Space Administration, Cryospheric Sciences and Modeling, Analysis and Prediction Programs

Seroussi, H. L.; Morlighem, M.; Rignot, E. J.; Larour, E. Y.; Mouginot, J.; Khazendar, A.

2013-12-01

167

Mathematical modeling of the Drosophila neuromuscular junction  

OpenAIRE

Poster presentation: An important challenge in neuroscience is understanding how networks of neurons go about processing information. Synapses are thought to play an essential role in cellular information processing however quantitative and mathematical models of the underlying physiologic processes that occur at synaptic active zones are lacking. We are generating mathematical models of synaptic vesicle dynamics at a well-characterized model synapse, the Drosophila larval neuromuscular junct...

Knodel, Markus M.; Bucher, Daniel B.; Queisser, Gillian; Schuster, Christoph; Wittum, Gabriel

2009-01-01

168

Neuromuscular Diseases Associated with HIV-1 Infection  

OpenAIRE

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

Robinson-papp, Jessica; Simpson, David M.

2009-01-01

169

Neuromuscular Fatigue During 200 M Breaststroke  

OpenAIRE

The aims of this study were: i) to analyze activation patterns of four upper limb muscles (duration of the active and non-active phase) in each lap of 200m breaststroke, ii) quantify neuromuscular fatigue, with kinematics and physiologic assessment. Surface electromyogram was collected for the biceps brachii, deltoid anterior, pectoralis major and triceps brachii of nine male swimmers performing a maximal 200m breaststroke trial. Swimming speed, SL, SR, SI decreased from the 1st to the 3rd la...

Ana Conceição; Anto?nio J Silva, Tiago Barbosa

2014-01-01

170

Update on the management of neuromuscular block: focus on sugammadex  

OpenAIRE

Steroidal neuromuscular blocking agents (NMBAs), such as rocuronium, are widely used in clinical anesthesia and emergency medicine to facilitate endotracheal intubation and artificial ventilation and to allow surgical access to body cavities. Reversal of neuromuscular blockade is important for the acceleration of patient recovery and prevention of postoperative residual neuromuscular blockade and reduces the incidence of severe morbidity and mortality associated with anesthesia management. Su...

Boer, Hans D.; Egmond, Jan; Driessen, Jacques J.; Booij, Leo Hd

2007-01-01

171

Surgical advances in the treatment of neuromuscular scoliosis  

OpenAIRE

Neuromuscular disorders are a group of diseases affecting the neuro-musculo-skeletal system. Children with neuromuscular disorders frequently develop progressive spinal deformities with cardio-respiratory compromise in the most severe cases. The incidence of neuromuscular scoliosis is variable, inversely correlated with ambulatory abilities and with a reported risk ranging from 80% to 100% in non-ambulatory patients. As surgical and peri-operative techniques have improved, more severely affec...

Canavese, Federico; Rousset, Marie; Le Gledic, Benoit; Samba, Antoine; Dimeglio, Alain

2014-01-01

172

Lower tibial than peroneal compound muscle action potential amplitude in neuromuscular diseases.  

Science.gov (United States)

The pattern of findings on nerve conduction studies is an important component of an electrodiagnostic evaluation to assess for peripheral neuromuscular disorders. The aim of this study was to determine the extent to which a lower tibial compound muscle action potential (CMAP) amplitude compared with the peroneal CMAP amplitude is more indicative of specific neuromuscular disorders such as S1 radiculopathies, sciatic neuropathies, or peripheral neuropathies. The electromyographic (EMG) findings of 921 patients who had undergone an EMG of the lower extremity and in whom the EMG study was interpreted as normal or a single neuromuscular diagnosis was identified were retrospectively reviewed to determine the frequency of an absolutely lower tibial than peroneal CMAP amplitude. Thirty-five (7%) healthy subjects had a lower tibial than peroneal CMAP amplitude (i.e., the absolute value of the tibial CMAP was lower than the absolute value of the peroneal CMAP), despite both values being in normal range. The finding on nerve conduction study of an absolutely lower tibial than peroneal CMAP occurred in a significantly higher proportion of patients with a diffuse polyneuropathy (24%) and S1 radiculopathies (21%) compared with controls. The findings suggest that in subjects in whom lower extremity nerve conduction study demonstrates an absolutely lower tibial than peroneal CMAP amplitude, neuromuscular disorders such as a polyneuropathy or S1 radiculopathy should be considered. PMID:20844444

Rubin, Devon I; Whaley, Nathaniel R

2010-10-01

173

Neuromuscular scoliosis - surgical management and outcomes  

Scientific Electronic Library Online (English)

Full Text Available 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.

174

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

Directory of Open Access Journals (Sweden)

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

Daniel Bechara Jacob Ferreira

2006-01-01

175

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

Scientific Electronic Library Online (English)

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

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

176

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

177

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

178

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

179

Two Mechanisms to Avoid Control Conflicts Resulting from Uncoordinated Intent  

Science.gov (United States)

This software implements a real-time access control protocol that is intended to make all connected users aware of the presence of other connected users, and which of them is currently in control of the system. Here, "in control" means that a single user is authorized and enabled to issue instructions to the system. The software The software also implements a goal scheduling mechanism that can detect situations where plans for the operation of a target system proposed by different users overlap and interact in conflicting ways. In such situations, the system can either simply report the conflict (rejecting one goal or the entire plan), or reschedule the goals in a way that does not conflict. The access control mechanism (and associated control protocol) is unique. Other access control mechanisms are generally intended to authenticate users, or exclude unauthorized access. This software does neither, and would likely depend on having some other mechanism to support those requirements.

Mishkin, Andrew H.; Dvorak, Daniel L.; Wagner, David A.; Bennett, Matthew B.

2013-01-01

180

Inter-animal variability in the effects of C-type allatostatin on the cardiac neuromuscular system in the lobster Homarus americanus  

Science.gov (United States)

SUMMARY Although the global effects of many modulators on pattern generators are relatively consistent among preparations, modulators can induce different alterations in different preparations. We examined the mechanisms that underlie such variability in the modulatory effects of the peptide C-type allatostatin (C-AST; pQIRYHQCYFNPISCF) on the cardiac neuromuscular system of the lobster Homarus americanus. Perfusion of C-AST through the semi-intact heart consistently decreased the frequency of ongoing contractions. However, the effect of C-AST on contraction amplitude varied between preparations, decreasing in some preparations and increasing in others. To investigate this variable effect, we examined the effects of C-AST both peripherally and centrally. When contractions of the myocardium were elicited by controlled stimuli, C-AST did not alter heart contraction at the periphery (myocardium or neuromuscular junction) in any hearts. However, when applied either to the semi-intact heart or to the cardiac ganglion (CG) isolated from hearts that responded to C-AST with increased contraction force, C-AST increased both motor neuron burst duration and the number of spikes per burst by about 25%. In contrast, CG output was increased only marginally in hearts that responded to C-AST with a decrease in contraction amplitude, suggesting that the decrease in amplitude in those preparations resulted from decreased peripheral facilitation. Our data suggest that the differential effects of a single peptide on the cardiac neuromuscular system are due solely to differential effects of the peptide on the pattern generator; the extent to which the peptide induces increased burst duration is crucial in determining its overall effect on the system. PMID:22675192

Wiwatpanit, Teerawat; Powers, Brian; Dickinson, Patsy S.

2012-01-01

181

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

Science.gov (United States)

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

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

2014-09-01

182

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

OpenAIRE

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

183

Mechanism and control of remote manipulators  

International Nuclear Information System (INIS)

Demands are increasing on remote manipulators for various tasks under environment hazardous to man. Though master-slave manipulators for cranes were developed in U.S.A. and Europe, they do not have sufficient moving area. For the purpose of developing articulated remote manipulators with mounted robots, three types of novel remote manipulators differing in driving mechanisms were tentatively constructed to make studies on servo and operational characteristics. Herein accounted are the drive and servo mechanisms, the results of performance tests and operational evaluation. (author)

184

Oil pollution control mechanisms - statutes and regulations  

International Nuclear Information System (INIS)

The purpose of this analysis is to provide a detailed picture of federal statutes and regulations, as well as case law, bearing on oil spill prevention and control. Emphasis has been placed on federal action occurring after a spill, although some effort is directed toward review of prevention statutes and regulations. In-depth consideration is given the control of oil pollution under the Federal Water Pollution Control Act but this analysis also touches lightly upon acts that have a lesser effect on oil pollution control. These acts being: The Refuse Act; The Ports and Waterways Safety Act of 1972; The Outer Continental Shelf Lands Act; The Oil Pollution Act of 1961; The Deepwater Port Act of 1974, and The Fish and Wildlife Coordination Act

185

Control Engineering Analysis of Mechanical Pitch Systems  

Science.gov (United States)

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

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

2014-12-01

186

[Mechanical ventilation in children  

Science.gov (United States)

OBJECTIVE: To make a brief review about mechanical ventilation in Pediatrics.METHODS: Review of the classification of types of mechanical ventilation, characteristics of pression and flow waves and indications for its installation. In a sequential way we discuss the various modes of ventilation (control ventilation, assisted-control ventilation, assisted ventilation, intermittent mandatory ventilation, synchronized intermittent mandatory ventilation, pressure-support ventilation) showing some advantages and disadvantages of using these modes. RESULTS: General rules for mechanical ventilation are presented, considering some specific pathologies in Pediatrics (acute respiratory distress syndrome, bronchopleural fistulae, cranial trauma, cardiac failure, neuromuscular pathology, acute asthma and in patients with acute descompensation of a cronic respiratory failure). CONCLUSIONS: Some limitations of mechanical ventilation and the possible advances in a short period are presented. PMID:14685580

Carvalho, W B

1998-07-01

187

Recent achievements in restorative neurology: Progressive neuromuscular diseases  

International Nuclear Information System (INIS)

This book contains 27 chapters. Some of the chapter titles are: Computed Tomography of Muscles in Neuromuscular Disease; Mapping the Genes for Muscular Dystrophy; Trophic Factors and Motor Neuron Development; Size of Motor Units and Firing Rate in Muscular Dystrophy; Restorative Possibilities in Relation to the Pathology of Progressive Neuromuscular Disease; and An Approach to the Pathogenesis of some Congenital Myopathies

188

Motoneuron and sensory neuron plasticity to varying neuromuscular activity levels  

Science.gov (United States)

The size and phenotypic properties of the neural and muscular elements of the neuromuscular unit are matched under normal conditions. When subjected to chronic decreases or increases in neuromuscular activity, however, the adaptations in these properties are much more limited in the neural compared with the muscular elements.

Ishihara, Akihiko; Roy, Roland R.; Ohira, Yoshinobu; Edgerton, V. Reggie

2002-01-01

189

Robust Position Control of Electro-mechanical Systems  

Directory of Open Access Journals (Sweden)

Full Text Available In this work, the robust position control scheme is proposed for the electro-mechanical system using the disturbance observer and backstepping control method. To the external unknown load of the electro-mechanical system, the nonlinear disturbance observer is given to estimate the external unknown load. Combining the output of the developed nonlinear disturbance observer with backstepping technology, the robust position control scheme is proposed for the electro-mechanical system. The stability of the closed-loop control system has been proved via the Lyapunov analysis technique. Simulation results are presented to demonstrate the feasibility of the proposed disturbance-observer-based position control scheme of the electro-mechanical system.

Rong Mei

2013-01-01

190

Molecular Mechanisms Controlling GLUT4 Intracellular Retention  

OpenAIRE

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

Blot, Vincent; Mcgraw, Timothy E.

2008-01-01

191

Optimal Tuning for Disturbance Suppression Mechanism for Model Predictive Control  

Science.gov (United States)

Disturbance suppression is one of most required performances in process control. We recently proposed a new disturbance suppression mechanism applicable for model predictive control in order to enhance disturbance suppression performance for ramp-like disturbances. The proposed method utilized the prediction error of controlled values and generates a disturbance compensation signal by a constant gain feedback. In this paper, we propose an improved version of the disturbance suppression mechanism by applying a low-pass filter and parameter tuning methods by which we can make the mechanism more tolerant to various disturbances such as ramp, step, and other supposable ones. We also show numerical simulation results with an oil distillation tower plant.

Tange, Yoshio; Nakazawa, Chikashi

192

Single-atom quantum control of macroscopic mechanical oscillators  

CERN Document Server

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

Bariani, F; Tan, Huatang; Meystre, P

2013-01-01

193

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

194

Cross-training effects of a proprioceptive neuromuscular facilitation exercise programme on knee musculature  

OpenAIRE

Objectives: To examine the cross-training effects of a proprioceptive neuromuscular facilitation training (PNF) program on peak torque and endurance. Design: Factorial design. Participants: Twenty-three males were assigned to a PNF group (n=12) or a control group (n=11). Interventions: The PNF program included training of the knee extensor and flexor muscles for a period of 8 weeks, exercising three times a week. PNF training included performance of knee movements through range of motion agai...

Kofotolis, N. D.; ??????????, ?. ?.; Kellis, E.; ???????, ?.

2010-01-01

195

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

OpenAIRE

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

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

2009-01-01

196

Role of analgesics, sedatives, neuromuscular blockers, and delirium.  

Science.gov (United States)

A major focus on critical care medicine concerns the institution of life-support therapies, such as mechanical ventilation, during periods of organ failure to permit a window of opportunity to diagnose and treat underlying disorders so that patients may be returned to their prior functional status upon recovery. With the growing success of these intensive care unit-based therapies and longer-term follow-up of patients, severe weakness involving the peripheral nervous system and muscles has been identified in many recovering patients, often confounding the time course or magnitude of recovery. Mechanical ventilation is often accompanied by pharmacologic treatments including analgesics, sedatives, and neuromuscular blockers. These drugs and the encephalopathies accompanying some forms of critical illness result in a high prevalence of delirium in mechanically ventilated patients. These drug effects likely contribute to an impaired ability to assess the magnitude of intensive care unit-acquired weakness, to additional time spent immobilized and mechanically ventilated, and to additional weakness from the patient's relative immobility and bedridden state. This review surveys recent literature documenting these relationships and identifying approaches to minimize pharmacologic contributions to intensive care unit-acquired weakness. PMID:20046129

Hall, Jesse B; Schweickert, William; Kress, John P

2009-10-01

197

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

198

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.)

199

INTERACTION OF VERAPAMIL AND LITHIUM AT THE NEUROMUSCULAR JUNCTION ON RAT ISOLATED MUSCLE-HEMIDIAPHRAGM  

Directory of Open Access Journals (Sweden)

Full Text Available It has been reported that cither lithium or verapamil can potentiate the neuromuscular blocking activity of certain neuromuscular blockers. In the present investigation, possible interaction of verapamil with lithium has been described. The dose ? response effects of verapamil and lithium on diaphragmatic contractility were assessed in vitro. Mechanical responses of the muscle to indirect (nerve and direct (muscle electrical stimulation were recorded. Verapamil depressed rat diaphragm twitch tensions induced by nerve stimulation in a dose - dependent manner with the 50 percent depression of the original twitch tensions (ICSQ by 5.6 xlO^mmol/l."nThe IC50 of verapamil for direct stimulation of the muscle was LI x W'5 mmol II. Partial replacement of sodium chloride by lithium chloride (0.5, 1.5 and 5 mmol /1 in the medium did not change the depressant effect of verapamil on muscle twitches induced by direct (muscle or indirect (nerve electrical stimulation.

H. R. Sadeghipour

1998-08-01

200

Sugammadex, a Neuromuscular Blockade Reversal Agent, Causes Neuronal Apoptosis in Primary Cultures  

Science.gov (United States)

Sugammadex, a ?-cyclodextrin that encapsulates selectively steroidal neuromuscular blocking agents, such as rocuronium or vecuronium, has changed the face of clinical neuromuscular pharmacology. Sugammadex allows a rapid reversal of muscle paralysis. Sugammadex appears to be safe and well tolerated. Its blood-brain barrier penetration is poor (Sugammadex in neurons in primary culture. Here we show that clinically relevant sugammadex concentrations cause apoptotic/necrosis neuron death in primary cultures. Studies on the underlying mechanism revealed that sugammadex-induced activation of mitochondria-dependent apoptosis associates with depletion of neuronal cholesterol levels. Furthermore SUG increase CytC, AIF, Smac/Diablo and CASP-3 protein expression in cells in culture. Potential association of SUG-induced alteration in cholesterol homeostasis with oxidative stress and apoptosis activation occurs. Furthermore, resistance/sensitivity to oxidative stress differs between neuronal cell types. PMID:23983586

Palanca, José M.; Aguirre-Rueda, Diana; Granell, Manuel V.; Aldasoro, Martin; Garcia, Alma; Iradi, Antonio; Obrador, Elena; Mauricio, Maria Dolores; Vila, Jose; Gil-Bisquert, Anna; Valles, Soraya L.

2013-01-01

201

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

202

Control of chaos: methods and applications in mechanics.  

Science.gov (United States)

A survey of the field related to control of chaotic systems is presented. Several major branches of research that are discussed are feed-forward ('non-feedback') control (based on periodic excitation of the system), the 'Ott-Grebogi-Yorke method' (based on the linearization of the Poincaré map), the 'Pyragas method' (based on a time-delayed feedback), traditional for control-engineering methods including linear, nonlinear and adaptive control. Other areas of research such as control of distributed (spatio-temporal and delayed) systems, chaotic mixing are outlined. Applications to control of chaotic mechanical systems are discussed. PMID:16893789

Fradkov, Alexander L; Evans, Robin J; Andrievsky, Boris R

2006-09-15

203

The neuromuscular blocking activity of spectinomycin on the rat sciatic nerve-gastrocnemius muscle preparation.  

Science.gov (United States)

Spectinomycin displays a dose-dependent neuromuscular blocking activity in vivo. The neuromuscular blockade elicited by spectinomycin is potentiated by d-tubocurarine. Neostigmine methylsulfate is unable to reverse the neuromuscular blocking activity of spectinomycin, whereas calcium chloride counteracts the neuromuscular blockade induced by this antibiotic. PMID:3016766

Renna, G; Cagiano, R; Fiore, T; Cuomo, V

1986-05-01

204

Molecular motors: design, mechanism and control  

CERN Document Server

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

Chowdhury, Debashish

2007-01-01

205

Novel Mechanism Control Algorithm for Wired Network  

Directory of Open Access Journals (Sweden)

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

V. B. Kirubanand

2011-01-01

206

Neuromuscular blocking effects of vecuronium in dogs with autosomal-recessive centronuclear myopathy.  

Science.gov (United States)

OBJECTIVE To evaluate the potency of vecuronium and duration of vecuronium-induced neuromuscular blockade in dogs with centronuclear myopathy (CNM). ANIMALS 6 Labrador Retrievers with autosomal-recessive CNM and 5 age- and weight-matched control dogs. PROCEDURES Dogs were anesthetized on 2 occasions (1-week interval) with propofol, dexmedetomidine, and isoflurane. Neuromuscular function was monitored with acceleromyography and train-of-four (TOF) stimulation. In an initial experiment, potency of vecuronium was evaluated by a cumulative-dose method, where 2 submaximal doses of vecuronium (10 ?g/kg each) were administered IV sequentially. For the TOF's first twitch (T1), baseline twitch amplitude and maximal posttreatment depression of twitch amplitude were measured. In the second experiment, dogs received vecuronium (50 ?g/kg, IV) and the time of spontaneous recovery to a TOF ratio (ie, amplitude of TOF's fourth twitch divided by amplitude of T1) ? 0.9 and recovery index (interval between return of T1 amplitude to 25% and 75% of baseline) were measured. RESULTS Depression of T1 after each submaximal dose of vecuronium was not different between groups. Median time to a TOF ratio ? 0.9 was 76.7 minutes (interquartile range [IQR; 25th to 75th percentile], 66.7 to 99.4 minutes) for dogs with CNM and 75.0 minutes (IQR, 47.8 to 96.5 minutes) for controls. Median recovery index was 18.0 minutes (IQR, 9.7 to 23.5 minutes) for dogs with CNM and 20.2 minutes (IQR, 8 to 25.1 minutes) for controls. CONCLUSIONS AND CLINICAL RELEVANCE For the study dogs, neither potency nor duration of vecuronium-induced neuromuscular blockade was altered by CNM. Vecuronium can be used to induce neuromuscular blockade in dogs with autosomal-recessive CNM. PMID:25815571

Martin-Flores, Manuel; Paré, Monique D; Tomak, Emily A; Corn, Morgan L; Campoy, Luis

2015-04-01

207

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

Science.gov (United States)

The neuromodulation of motor excitability has been shown to improve functional movement in people with central nervous system damage. This study aimed to investigate the mechanism of peripheral neuromuscular electrical stimulation (NMES) in motor excitability and its effects in people with spinocerebellar ataxia (SCA). This single-blind case-control study was conducted on young control (n=9), age-matched control (n=9), and SCA participants (n=9; 7 SCAIII and 2 sporadic). All participants received an accumulated 30min of NMES (25Hz, 800ms on/800ms off) of the median nerve. The central motor excitability, measured by motor evoked potential (MEP) and silent period, and the peripheral motor excitability, measured by the H-reflex and M-wave, were recorded in flexor carpi radialis (FCR) muscle before, during, and after the NMES was applied. The results showed that NMES significantly enhanced the MEP in all 3 groups. The silent period, H-reflex and maximum M-wave were not changed by NMES. We conclude that NMES enhances low motor excitability in patients with SCA and that the mechanism of the neuromodulation was supra-segmental. These findings are potentially relevant to the utilization of NMES for preparation of motor excitability. The protocol was registered at Clinicaltrials.gov (NCT02103075). PMID:25434572

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

2015-02-01

208

Analysis and Comparison of Access Control Policies Validation Mechanisms  

Directory of Open Access Journals (Sweden)

Full Text Available Validation and verification of security policies is a critical and important task to ensure that access control policies are error free. The two most common problems present in access control policies are: inconsistencies and incompleteness. In order to detect such problems, various access control policy validation mechanisms are proposed by the researchers. However, comprehensive analysis and evaluation of the existing access control policy validation techniques is missing in the literature. In this paper, we have provided a first detailed survey of this domain and presented the taxonomy of the access control policy validation mechanisms. Furthermore, we have provided a qualitative comparison and trend analysis of the existing schemes. From this survey, we found that only few validation mechanisms exist that can handle both inconsistency and incompleteness problem. Also, most of the policy validation techniques are inefficient in handling continuous values and Boolean expressions.

Muhammad Aqib

2014-12-01

209

Eye mechanics and their implications for eye movement control  

OpenAIRE

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

210

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 sistémicas 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.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 diseases. 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 quadriplegia which most typical manifestation is the need for assisted ventilation and/or

A. Mesejo

2006-05-01

211

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

212

Neural Control Mechanisms and Body Fluid Homeostasis  

Science.gov (United States)

The goal of the proposed research was to study the nature of afferent signals to the brain that reflect the status of body fluid balance and to investigate the central neural mechanisms that process this information for the activation of response systems which restore body fluid homeostasis. That is, in the face of loss of fluids from intracellular or extracellular fluid compartments, animals seek and ingest water and ionic solutions (particularly Na(+) solutions) to restore the intracellular and extracellular spaces. Over recent years, our laboratory has generated a substantial body of information indicating that: (1) a fall in systemic arterial pressure facilitates the ingestion of rehydrating solutions and (2) that the actions of brain amine systems (e.g., norepinephrine; serotonin) are critical for precise correction of fluid losses. Because both acute and chronic dehydration are associated with physiological stresses, such as exercise and sustained exposure to microgravity, the present research will aid in achieving a better understanding of how vital information is handled by the nervous system for maintenance of the body's fluid matrix which is critical for health and well-being.

Johnson, Alan Kim

1998-01-01

213

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)

214

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

Science.gov (United States)

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

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

2014-09-01

215

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

216

Obesity and upper airway control during sleep  

OpenAIRE

Mechanisms linking obesity with upper airway dysfunction in obstructive sleep apnea are reviewed. Obstructive sleep apnea is due to alterations in upper airway anatomy and neuromuscular control. Upper airway structural alterations in obesity are related to adipose deposition around the pharynx, which can increase its collapsibility or critical pressure (Pcrit). In addition, obesity and, particularly, central adiposity lead to reductions in resting lung volume, resulting in loss of caudal trac...

Schwartz, Alan R.; Patil, Susheel P.; Squier, Samuel; Schneider, Hartmut; Kirkness, Jason P.; Smith, Philip L.

2009-01-01

217

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

Science.gov (United States)

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

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

2014-10-15

218

Influence of neostigmine treatment on embryonic development of acetylcholine receptors and neuromuscular junctions.  

Science.gov (United States)

The postulated role of the acetylcholine receptor in the formation of neuromuscular synapses during the course of embryonic development was investigated in the superior oblique muscle of white Peking duck embryos. The possibility that the number of receptors could be experimentally lowered by chronic injections of the anticholinesterase agent, neostigmine methylsulfate, was determined using 125I-alpha-bungarotoxin. The total number of acetylcholine receptors on incubation day 12, 2 d subsequent to the onset of treatment, was reducted 45% as compared to saline-treated controls. A similar reduction in total receptor content (49%) was also observed on day 19. Radioautographic preparations showed that clusters of acetylcholine receptors were rare and that the grain density of extrajunctional receptors was also reduced. Hence, chronic treatment with neostigimine during development was observed to exert an effect on both the number and distribution of receptors in the developing superior oblique muscle. These changes occurred in the absence of any apparent effect on muscle differentiation in general. Myoblasts and myotubes were present on day 14 and further differentiated into myofibers by day 18 in both neostigmine and saline-treated muscles. The cytology of the develop;ing muscle cells also appeared normal. This is in contradistinction to the striking morphological changes that take place in adult mammalian and avian muscle after anticholinesterase treatment. More significantly, the decreased total receptor content and sparsity of clusters had no apparent effect on the formation of developing neuromuscular junctions at the electron microscopic level. The frequency of neuromuscular junctions in neostigmine-treated muscles was similar to that of the controls. It is concluded that acetylcholine receptor clusters are not required for the events leading to the morphological formation of neuromuscular junctions during in vivo development. PMID:7130270

Sohal, G S; Boydston, W R

1982-09-01

219

?????????????????? Brown Adipose 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

220

Sliding mode control on electro-mechanical systems  

OpenAIRE

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

Utkin, Vadim I.; Hao-Chi Chang

2002-01-01

221

Research on Internal Flow Control Mechanism of For CES Routers  

OpenAIRE

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 Prob...

Bin Zhuge; Cheng Yu; Kang-ping Liu; Wei-ming Wang

2011-01-01

222

A systematic literature review on the use of proprioceptive neuromuscular facilitation in neuromuscular rehabilitation  

OpenAIRE

The purpose of this thesis was to review and critically analyze the literatures from 1990 to 2013 in order to investigate the methodological quality of the studies, indications and goals of PNF treatment, and to explore the components of PNF that are being used in treatment of neurological disorders. And to overview on the effectiveness and use of PNF approach in neuromuscular rehabilitation through the findings of this study. The research method used for this thesis was systematic litera...

Shrestha, Yugal

2013-01-01

223

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

224

Neuromuscular ultrasound findings in polyneuropathy secondary to disulfiram.  

Science.gov (United States)

Disulfiram toxicity can cause multiple neurologic problems, including a reversible distal sensorimotor axonal polyneuropathy. Although electrodiagnosis and biopsy results have been described in the diagnosis and management of patients with disulfiram associated polyneuropathy, neuromuscular ultrasound findings have not been reported. The authors present a case of electrodiagnostically confirmed axonal polyneuropathy with relative sural sparing secondary to disulfiram and describe the neuromuscular ultrasound findings in this individual. Ultrasound demonstrated distal enlargement with slight side-to-side asymmetry and normal proximal cross-sectional area in the lower extremity nerves. Neuromuscular ultrasound is another diagnostic modality that may be used to assist in the diagnosis of patients with polyneuropathy secondary to disulfiram. PMID:25462150

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

2014-12-01

225

From neuromuscular activation to end-point locomotion: An artificial neural network-based technique for neural prostheses.  

Science.gov (United States)

Neuroprostheses, implantable or non-invasive ones, are promising techniques to enable paralyzed individuals with conditions, such as spinal cord injury or spina bifida (SB), to control their limbs voluntarily. Direct cortical control of invasive neuroprosthetic devices and robotic arms have recently become feasible for primates. However, little is known about designing non-invasive, closed-loop neuromuscular control strategies for neural prostheses. Our goal was to investigate if an artificial neural network-based (ANN-based) model for closed-loop-controlled neural prostheses could use neuromuscular activation recorded from individuals with impaired spinal cord to predict their end-point gait parameters (such as stride length and step width). We recruited 12 persons with SB (5 females and 7 males) and collected their neuromuscular activation and end-point gait parameters during overground walking. Our results show that the proposed ANN-based technique can achieve a highly accurate prediction (e.g., R-values of 0.92-0.97, ANN (tansig+tansig) for single composition of data sets) for altered end-point locomotion. Compared to traditional robust regression, this technique can provide up to 80% more accurate prediction. Our results suggest that more precise control of complex neural prostheses during locomotion can be achieved by engaging neuromuscular activity as intrinsic feedback to generate end-point leg movement. This ANN-based model allows a seamless incorporation of neuromuscular activity, detected from paralyzed individuals, to adaptively predict their altered gait patterns, which can be employed to provide closed-loop feedback information for neural prostheses. PMID:19389678

Chang, Chia-Lin; Jin, Zhanpeng; Chang, Hou-Cheng; Cheng, Allen C

2009-05-29

226

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

227

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

228

Pressure versus volume controlled modes in invasive mechanical ventilation.  

Science.gov (United States)

The first generation of mechanical ventilators were controlled and cycled by pressure. Unfortunately, they did not allow control of the delivered tidal volume under changes in the dynamics of the respiratory system. This led to a second generation of ventilators that allowed volume control, hence favoring the ventilatory strategy based on normalization of the arterial gases. Studies conducted in the 1980s which related lung injury to the high ventilator pressures utilized while treating acute respiratory distress syndrome patients renewed interest in pressure-controlled mechanical ventilation. In addition, new evidence became available, leading to the development of pulmonary protective strategies aiming at preventing the progression of ventilator-induced lung injury. This review provides a detailed description of the control of pressure or volume using certain ventilatory modes, and offers a general view of their advantages and disadvantages, based on the latest available evidence. PMID:23260264

Garnero, A J; Abbona, H; Gordo-Vidal, F; Hermosa-Gelbard, C

2013-05-01

229

From Neuromuscular Activation to End-point Locomotion: An Artificial Neural Network-based Technique for Neural Prostheses  

OpenAIRE

Neuroprostheses, implantable or non-invasive ones, are promising techniques to enable paralyzed individuals with conditions, such as spinal cord injury or spina bifida (SB), to control their limbs voluntarily. Direct cortical control of invasive neuroprosthetic devices and robotic arms have recently become feasible for primates. However, little is known about designing non-invasive, closed-loop neuromuscular control strategies for neural prostheses. Our goal was to investigate if an Artificia...

Chang, Chia-lin; Jin, Zhanpeng; Chang, Hou-cheng; Cheng, Allen C.

2009-01-01

230

[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

231

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

232

Study of Seed Dormancy Mechanisms; Causes and Control  

OpenAIRE

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 ...

Syeda Nasreen; Yousaf, M.; Mohmand, Akbar S.; Ashraf Mailk, M.

2002-01-01

233

Optimal piezo-electro-mechanical coupling to control plate vibrations  

OpenAIRE

A new way of coupling electrical and mechanical waves, using piezoelectric effect, is presented here. Since the energy exchange between two systems supporting wave propagation is maximum when their evolution is governed by similar equations, hence, an optimal electromechanical coupling is obtained by designing an electric network which is "analog" to the mechanical structure to be controlled. In this paper, we exploit this idea to enhance the coupling, between a Kirchhoff-Lo...

Alessandroni, Silvio; Isola, Francesco; Frezza, Fabrizio

2010-01-01

234

Control and shutdown mechanism operating experience of TAPS  

International Nuclear Information System (INIS)

Tarapur Atomic Power Station is one of the oldest operating GE, BWR units in the world. There are two independent types of reactivity control mechanisms to shutdown the reactor, namely fast acting CRD system and the slow acting liquid poison system in the event of any abnormal situations. The fast acting CRD system is also capable of maneuvering the reactor power. An effort is made here to highlight the features of these control mechanisms. This paper also describes valuable operating experiences and challenges faced in maintaining its availability and reliability. (author)

235

Dynamics and control of mechanical systems in offshore engineering  

CERN Document Server

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

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

2014-01-01

236

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

237

Squeezing of mechanical motion via qubit-assisted control  

Science.gov (United States)

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

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

2015-01-01

238

Investigation of the Profile Control Mechanisms of Dispersed Particle Gel  

OpenAIRE

Dispersed particle gel (DPG) particles of nano- to micron- to mm-size have been prepared successfully and will be used for profile control treatment in mature oilfields. The profile control and enhanced oil recovery mechanisms of DPG particles have been investigated using core flow tests and visual simulation experiments. Core flow test results show that DPG particles can easily be injected into deep formations and can effectively plug the high permeability zones. The high profile improvement...

Zhao, Guang; Dai, Caili; Zhao, Mingwei

2014-01-01

239

The Analysis on Financial Cooperative Controlling Mechanism of Enterprise Group  

OpenAIRE

As the core of modern market economy, enterprise group is an advanced form of organization after productive forces reached to a certain stage. For the reason of complexity and specificity of organizational form of enterprise group, the issue of financial cooperative control has been widespread concerned by theorists. Although many researches have been done, but there are still lacking of systematic research results especially in the fields of mechanism of financial cooperative control. After ...

Ziqin Feng

2010-01-01

240

Patient Machine Interface for the Control of Mechanical Ventilation Devices  

OpenAIRE

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, a...

Rolando Grave de Peralta; Sara Gonzalez Andino; Stephen Perrig

2013-01-01

241

An electrostatic gate for mechanically controlled single-molecule junctions  

International Nuclear Information System (INIS)

We present a fabrication scheme for a tunable single-molecule transistor that allows for controlling the electrode separation and provides an electrostatic gate. The experimental approach is based on the mechanically controlled break junction technique but integrates an additional bottom gate electrode and an uninterrupted high-? gate dielectric. The device performance is demonstrated for a single-molecule junction showing Coulomb blockade characteristics. (paper)

242

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

243

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

Science.gov (United States)

Adenosine 5'-triphosphate (ATP) is the main co-transmitter accompanying the release of acetylcholine from motor nerve terminals. Previously, we revealed the direct inhibitory action of extracellular ATP on transmitter release via redox-dependent mechanism. However, the receptor mechanism of ATP action and ATP-induced sources of reactive oxygen sources (ROS) remained not fully understood. In the current study, using microelectrode recordings of synaptic currents from the frog neuromuscular junction, we analyzed the receptor subtype involved in synaptic action of ATP, receptor coupling to NADPH oxidase and potential location of ATP receptors within the lipid rafts. Using subtype-specific antagonists, we found that the P2Y13 blocker 2-[(2-chloro-5-nitrophenyl)azo]-5-hydroxy-6-methyl-3-[(phosphonooxy)methyl]-4-pyridinecarboxaldehyde did not prevent the depressant action of ATP. In contrast, the P2Y12 antagonist 2-methylthioadenosine 5'-monophosphate abolished the inhibitory action of ATP, suggesting the key role of P2Y12 receptors in ATP action. As the action of ATP is redox-dependent, we also tested potential involvement of the NADPH oxidase, known as a common inducer of ROS. The depressant action of extracellular ATP was significantly reduced by diphenyleneiodonium chloride and 4-(2-aminoethyl)-benzenesulfonyl fluoride hydrochloride, two structurally different inhibitors of NADPH oxidase, indicating that this enzyme indeed mediates the action of ATP. Since the location and activity of various receptors are often associated with lipid rafts, we next tested whether ATP-driven inhibition depends on lipid rafts. We found that the disruption of lipid rafts with methyl-beta-cyclodextrin reduced and largely delayed the action of ATP. Taken together, these data revealed key steps in the purinergic control of synaptic transmission via P2Y12 receptors associated with lipid rafts, and identified NADPH oxidase as the main source of ATP-induced inhibitory ROS at the neuromuscular junction. Our data suggest that the location of P2Y receptors in lipid rafts speeds up the modulatory effect of ATP. Uncovered mechanisms may contribute to motor dysfunctions and neuromuscular diseases associated with oxidative stress. PMID:25463521

Giniatullin, A; Petrov, A; Giniatullin, R

2015-01-29

244

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

Scientific Electronic Library Online (English)

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

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

2008-02-01

245

Peripheral nerve and neuromuscular junction pathology in Pompe disease.  

Science.gov (United States)

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

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

2015-02-01

246

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

247

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

248

Three degree of freedom translational axis hand controller mechanism  

Science.gov (United States)

A hand controller which includes a hand grip having therein a mechanism for allowing truly linear motion along at least two axes by modifying a four-bar linkage with a second four-bar linkage to counteract any rotational motion that would otherwise occur.

Menahem, Israel (Inventor); Bacon, James (Inventor)

1993-01-01

249

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

250

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 | Languages: English, 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 laryngosco

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

2005-08-01

251

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

Directory of Open Access Journals (Sweden)

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

A. García de Lorenzo

2006-05-01

252

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

Scientific Electronic Library Online (English)

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

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

2006-05-01

253

Sliding mode control on electro-mechanical systems  

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Full Text Available The first sliding mode control application may be found in the papers back in the 1930s in Russia. With its versatile yet simple design procedure the methodology is proven to be one of the most powerful solutions for many practical control designs. For the sake of demonstration this paper is oriented towards application aspects of sliding mode control methodology. First the design approach based on the regularization is generalized for mechanical systems. It is shown that stability of zero dynamics should be taken into account when the regular form consists of blocks of second-order equations. Majority of applications in the paper are related to control and estimation methods of automotive industry. New theoretical methods are developed in the context of these studies: sliding made nonlinear observers, observers with binary measurements, parameter estimation in systems with sliding mode control.

Utkin Vadim I.

2002-01-01

254

Seismic analysis of control and safety rod drive mechanism  

International Nuclear Information System (INIS)

Control rod and its driving mechanism for a Fast Breeder Reactor is to facilitate safe shutdown of the reactor in case of emergency. A theoretical study on the seismic qualification of control and safety rod driving mechanism is carried out. Earthquake excitations under Operational Basis (ORE) and Safe Shutdown condition (SSE) are considered. The time required for the control rod to reach the bottom position in order to shut down the reaction under excited condition is traced out. The maximum displaced positions and extreme stresses in various parts of the system under excitations are evaluated. The system modeled using beam elements. The connections between different parts are modeled through rigid elements. The interaction between various parts are modeled using GAP elements. (author)

255

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

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Full Text Available 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.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 neuromuscular 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.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 case report aim at calling the attention to prolonged neuromuscular block after mivacurium and its management approaches. CASE REPORT: Patient scheduled for outpatient procedure presenting prolonged neuromuscular block after mivacurium. Diagnosis w

Karina Bernardi Pimenta

2005-10-01

256

A influência da fadiga neuromuscular e da acidose metabólica sobre a corrida de 400 metros Influence of neuromuscular fatigue and metabolic acidosis on the 400-meter race  

Directory of Open Access Journals (Sweden)

Full Text Available Exercícios inabituais podem levar a danos musculares que persistem por alguns dias diminuindo a capacidade de desempenho em decorrência da fadiga. Além disso, o aumento da acidose intramuscular pode limitar o metabolismo celular no processo de gerar trabalho. Com isso, esta pesquisa teve como finalidade analisar a influência da fadiga neuromuscular e da acidose metabólica sobre a corrida de 400 metros. Foram selecionados 20 indivíduos, sedentários, com idade entre 18 e 35 anos. Estes foram submetidos aos seguintes protocolos: teste incremental em esteira, para determinação do VO2max; limiares aeróbio e anaeróbio, teste de 400m (400/C, atividade pliométrica, com repouso ativo/passivo, seguida de corrida de 400m logo após (400/Pós e 24 horas após a atividade pliométrica (400/24h. Os resultados obtidos mostram que, quando comparados os grupos ativo e passivo, não apresentaram diferenças significantes no desempenho dos 400/ Pós, mas o tempo deste foi maior, para os dois grupos quando comparado com os 400/C. No entanto, o 400/24h não foi significantemente diferente quando comparado com o 400/C para ambos os grupos. Concluise que, independente do tipo de recuperação - ativa ou passiva -, a diminuição de desempenho em uma corrida de 400 metros após atividade pliométrica parece ser ocasionada por mecanismos neuromusculares que levam à fadiga e não a limitações metabólicas.Unusual exercises can lead to muscle damage that persists for a few days reducing performance ability due to fatigue onset. Moreover, intramuscular acidity increase can limit the cell metabolism in the process of producing work. Therefore, the objective of this research was to analyze the influence of neuromuscular fatigue and metabolic acidity in the 400 m race. The selected sample consisted of 20 sedentary individuals, aged between 18 and 35 years. They were submitted to the following protocols: treadmill incremental test for determination of VO2max; aerobic and anaerobic threshold; 400m race test (400/R; plyometric activity with active/passive rest followed by 400m race immediately after (400/Post and 24 hours after the plyometric activity (400/24h. The obtained results show that when the active and passive groups are compared, they do not show significant difference in 400/Post performance, but this time was longer for both groups when compared with the 400/R. Nevertheless, the 400/24h was not significantly different when compared with the 400/R to both groups. It was concluded that regardless of the kind of recovery, active or passive, the performance reduction in a 400-meter race after plyometric activity seems to occur by neuromuscular mechanisms that lead to fatigue and not to metabolic limitations.

Flávio Roberto Pelicer

2011-04-01

257

Use of focal mechanisms to determine stress: A control study  

Science.gov (United States)

To allow focal mechanisms to be inverted for the stress field requires a different inversion algorithm than for slickenside data because focal mechanisms do not represent fault slip data unless one can decide which nodal plane is the fault plane. If one can decide which nodal plane is the fault plane, then the focal mechanisms can be inverted with the slickenside inversion algorithm. This decision cannot always be made, so algorithms for inverting focal mechanisms for the stress field are studied. These algorithms either use both of the possible fault planes or attempt to choose the correct fault plane while determining the stress tensor. Simulated focal mechanisms are made from slickenside data and used to provide a control study for the focal mechanism inversion algorithms. The results of this control study show that focal mechanisms can be inverted to find the best stress tensor, but the resolution is decreased unless the fault planes can be picked a priori. The resolution can also be increased by including constraints on the magnitude of the tangential traction on the fault plane. Therefore, using focal mechanisms to study small variations in the stress field requires that other data (e.g., studies of the hypocenters, surface faulting, or structural information concerning the region) be introduced to pick which of the nodal planes is the fault plane. This study also introduces the method of bootstrap resampling to the statistics of this problem. The non-Gaussian nature of the data makes the nonparametric formulation of the bootstrap approach ideal for this problem.

Michael, Andrew Jay

1987-01-01

258

Neuromuscular Fatigue During 200 M Breaststroke  

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

Ana Conceição

2014-03-01

259

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)

260

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

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

Roger Álvarez Fiallo

2005-06-01

261

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

262

Ecological production of dryland hairy vetch by mechanical control  

OpenAIRE

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

Avci, Muzaffer; Akar, Taner

2006-01-01

263

The effectiveness of neuromuscular warm-up strategies, that require no additional equipment, for preventing lower limb injuries during sports participation: a systematic review  

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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

264

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

OpenAIRE

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

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

2012-01-01

265

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

266

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

267

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

Scientific Electronic Library Online (English)

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

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

2013-12-01

268

Activity-Dependent Regulation of the Binomial Parameters p and n at the Mouse Neuromuscular Junction In Vivo  

OpenAIRE

Block of neurotransmission at the mammalian neuromuscular junction triggers an increase in the number of vesicles released (quantal content). The increase occurs whether nerve and muscle activity are both blocked by placement of a tetrodotoxin (TTX) containing cuff on the nerve or whether muscle activity is selectively blocked by injection of ?-bungarotoxin (BTX). We used ANOVA to examine whether the mechanism underlying the increase in quantal content differed between the two types of activ...

Wang, Xueyong; Wang, Qingbo; Engisch, Kathrin L.; Rich, Mark M.

2010-01-01

269

Mechanisms in Adaptive Feedback Control: Photoisomerization in a Liquid  

International Nuclear Information System (INIS)

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

270

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

271

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

272

Mechanical impulses can control metaphase progression in a mammalian cell  

OpenAIRE

Chromosome segregation machinery is controlled by mechanochemical regulation. Tension in a mitotic spindle, which is balanced by molecular motors and polymerization-depolymerization dynamics of microtubules, is thought to be essential for determining the timing of chromosome segregation after the establishment of the kinetochore-microtubule attachments. It is not known, however, whether and how applied mechanical forces modulate the tension balance and chemically affect the molecular processe...

Itabashi, Takeshi; Terada, Yasuhiko; Kuwana, Kenta; Kan, Tetsuo; Shimoyama, Isao; Ishiwata, Shin’ichi

2012-01-01

273

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

Science.gov (United States)

In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation, the formation of single dominant population, displacement of native plants and sustainable management strategies were investigated. The present results helped to clarify and explain such issues as the adaptability post invasion, interaction and competition between inter- and intra-species and community resistance, thereby providing important references to researches on other invasive alien species. PMID:21046320

Wan, FangHao; Liu, WanXue; Guo, JianYing; Qiang, Sheng; Li, BaoPing; Wang, JinJun; Yang, GuoQing; Niu, HongBang; Gui, FuRong; Huang, WenKun; Jiang, ZhiLin; Wang, WenQi

2010-11-01

274

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

275

Mechanical control of heat conductivity in molecular chains.  

Science.gov (United States)

We discuss a possibility to control heat conductivity in molecular chains by means of external mechanical loads. To illustrate such possibilities we consider first well-studied one-dimensional chain with degenerate double-well potential of the nearest-neighbor interaction. We consider varying lengths 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 equilibria; therefore, one can say that formation of such structures mimics a process of plastic deformation. We demonstrate that such modification of the chain length can lead to quite profound (almost fivefold) reduction of the heat conduction coefficient. Even more profound effect is revealed for a model with a single-well nonconvex potential. It is demonstrated that in a certain range of constant external forcing, this model becomes effectively double-well and has a multitude of possible states of equilibrium for fixed value of the external load. Due to this degeneracy, the heat-conduction coefficient can be reduced by two orders of magnitude. We suggest a mechanical model of a chain with periodic double-well potential, which allows control of the heat transport. The models considered may be useful for description of heat transfer in biological macromolecules and for control of the heat transport in microsystems. The possibility of the heat transport control in more realistic three-dimensional systems is illustrated by simulation of a three-dimensional model of polymer ?-helix. In this model, the mechanical stretching also brings about the structural inhomogeneity and, in turn, to essential reduction of the heat conductivity. PMID:24580199

Savin, A V; Gendelman, O V

2014-01-01

276

Control rod drive mechanism test program. Revision 3  

International Nuclear Information System (INIS)

This report describes the testing and development of three control rod drive mechanisms, Types A, B, and C, for use on commercial PWR plants designed by B and W. The three parts of the report describe each of the drives and the individual testing performed to verify the structural and functional adequacy of each drive. The test results indicate that all three drives are reliable and ensure safe, dependable reactor operation

277

Immunosensor with Fluid Control Mechanism for Salivary Cortisol Analysis  

OpenAIRE

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

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

2012-01-01

278

Phase diagram of ferroelectric nanowires and its mechanical force controllability  

Science.gov (United States)

A phenomenological thermodynamic model of ferroelectric nanowires is developed to investigate the size-temperature phase diagrams. Considering existence of the surface tension, size, and external applied stress effects, the approximated expressions of the transition temperatures at which the paraelectric phase loses its stability with respect to the appearance of the spontaneous polarization are derived. At the same time, the size-temperature phase diagrams as functions of the ferroelectric nanowire radius are obtained, and also show its external mechanical stress controllability.

Lin, S. P.; Zheng, Yue; Cai, M. Q.; Wang, Biao

2010-06-01

279

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.

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

2013-11-01

280

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

281

Underlying mechanisms in size control of uniform nanoparticles.  

Science.gov (United States)

Insights are given into underlying mechanisms for size control of uniform nanoparticles in liquid phases. At the outset, instead of the classical nucleation theories, which are hardly applicable to the size control of uniform particles, a fundamental equation for the nucleation of monodisperse particles, derived for their size control on the basis of the LaMer model, is introduced. This equation was derived on three assumptions: (1) There is a mass balance between the supply rate of solute and its consumption rate for nucleation and growth of the generated nuclei; (2) The supply rate of solute is independent of the subsequent precipitation events; (3) The nucleation rate is controlled only by the growth of the preformed nuclei at a fixed supply rate of solute. Thus, this nucleation theory is applicable to a system in which the precursor solute is supplied by slow irreversible generation in a closed system or by continuous feed from outside in an open system. However, it is inapplicable even if only one of these three assumptions is not fulfilled. Examples of applicable and inapplicable systems are listed, and finally discussion is focused on the underlying mechanisms of size control in some unique processes chosen from them, such as hydrolysis-induced precipitation of AgCl nanoparticles, double-jet precipitation of AgCl nanoparticles in a reverse micelle system to resolve the mechanism of particle formation in general reverse micelle systems, and a gel-sol process for the formation of nanoparticles of anatase TiO2. PMID:17336993

Sugimoto, Tadao

2007-05-01

282

Toxoplasmic encephalitis during mycophenolate mofetil immunotherapy of neuromuscular disease  

Science.gov (United States)

Objective: To show that immunotherapy with medications such mycophenolate mofetil (MMF) can cause serious complications in patients with neuromuscular disorders. Methods: Two patients with neuromuscular disorders on immunotherapy with long-term MMF who developed toxoplasmic encephalitis (TE) were included in this case series. Results: One patient with myasthenia gravis and one patient with inflammatory myopathy on immunotherapy with long-term MMF developed severe TE. Diagnosis was based on clinical presentation, MRI brain imaging characteristics, and CSF PCR positivity for Toxoplasma gondii. Both patients were treated with pyrimethamine, sulfadiazine, and leucovorin for 2 months without clinical improvement, and both died. Conclusions: Immunotherapy with medications such as MMF can cause devastating TE in non-HIV patients with neuromuscular disorders. Early consideration and recognition of this complication is important to possibly prevent unfavorable outcomes. The utility of screening and prophylaxis against toxoplasmosis in individuals with neuroimmunologic disorders and other autoimmune disorders who receive immunosuppressive therapy requires future study. PMID:25635260

Chahin, Nizar

2015-01-01

283

Mechanical impulses can control metaphase progression in a mammalian cell.  

Science.gov (United States)

Chromosome segregation machinery is controlled by mechanochemical regulation. Tension in a mitotic spindle, which is balanced by molecular motors and polymerization-depolymerization dynamics of microtubules, is thought to be essential for determining the timing of chromosome segregation after the establishment of the kinetochore-microtubule attachments. It is not known, however, whether and how applied mechanical forces modulate the tension balance and chemically affect the molecular processes involved in chromosome segregation. Here we found that a mechanical impulse externally applied to mitotic HeLa cells alters the balance of forces within the mitotic spindle. We identified two distinct mitotic responses to the applied mechanical force that either facilitate or delay anaphase onset, depending on the direction of force and the extent of cell compression. An external mechanical impulse that physically increases tension within the mitotic spindle accelerates anaphase onset, and this is attributed to the facilitation of physical cleavage of sister chromatid cohesion. On the other hand, a decrease in tension activates the spindle assembly checkpoint, which impedes the degradation of mitotic proteins and delays the timing of chromosome segregation. Thus, the external mechanical force acts as a crucial regulator for metaphase progression, modulating the internal force balance and thereby triggering specific mechanochemical cellular reactions. PMID:22523237

Itabashi, Takeshi; Terada, Yasuhiko; Kuwana, Kenta; Kan, Tetsuo; Shimoyama, Isao; Ishiwata, Shin'ichi

2012-05-01

284

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

Scientific Electronic Library Online (English)

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

Leonardo Abdala, Elias; André Fabio, Kohn.

2013-09-01

285

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 | Languages: English, 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 approa

Karina Bernardi, Pimenta.

2005-10-01

286

Neuromuscular exercise as treatment of degenerative knee disease  

DEFF Research Database (Denmark)

Exercise is recommended as first-line treatment of degenerative knee disease. Our hypothesis is that neuromuscular exercise is feasible and at least as effective as tradionally used strength or aerobic training, but aims to more closely target the sensorimotor deficiencies and functional instability associated with the degenerative knee disease than traditionally used training methods.SUMMARY FOR TABLE OF CONTENTS PAGECurrent data suggests that the effect from neuromuscular exercise on pain and function is comparable to the effects seen from other forms of exercise.

Ageberg, Eva; Roos, Ewa M.

2015-01-01

287

Motor Imagery Boosts Proprioceptive Neuromuscular Facilitation in the Attainment and Retention of Range-of -Motion at the Hip Joint  

OpenAIRE

This study examined the effect of proprioceptive neuromuscular facilitation (PNF) coupled with an internal mental imagery technique (PNFI) on both the attainment and retention of increased range-of-movement (ROM) at the hip joint. Twenty-four young adult subjects were randomly allocated to PNF, PNFI, and control treatments administered in fifteen sessions over a three-week period. ROM was assessed prior to training then at the completion of sessions 1 day, 3, 7, and 14 during training, then 2...

Michael Callaghan; Odley, Jenna L.; Williams, John G.

2004-01-01

288

Sugammadex compared with neostigmine/glycopyrrolate for routine reversal of neuromuscular block: a systematic review and economic evaluation†  

OpenAIRE

The cost-effectiveness of sugammadex for the routine reversal of muscle relaxation produced by rocuronium or vecuronium in UK practice is uncertain. We performed a systematic review of randomized controlled trials of sugammadex compared with neostigmine/glycopyrrolate and an economic assessment of sugammadex for the reversal of moderate or profound neuromuscular block (NMB) produced by rocuronium or vecuronium. The economic assessment aimed to establish the reduction in recovery time and the ...

Paton, F.; Paulden, M.; Chambers, D.; Heirs, M.; Duffy, S.; Hunter, J. M.; Sculpher, M.; Woolacott, N.

2010-01-01

289

Mechanisms of flow control with the unsteady bleed technique  

Science.gov (United States)

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

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

1992-01-01

290

Dolor en niños y adolescentes con enfermedades neuromusculares / Pain in children and adolescents with neuromuscular diseases  

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish El objetivo de este trabajo es revisar la información disponible sobre la experiencia de dolor en niños y adolescentes con una enfermedad neuromuscular (ENM). Para ello, se examinaron las bases de datos SCOPUS y MEDLINE y se localizaron los artículos publicados sobre el tema hasta marzo de 2012. Tra [...] s un análisis exhaustivo, se identificaron 33 artículos que cumplían con los criterios de inclusión. Del análisis efectuado se desprende que el dolor es una experiencia muy habitual en estos jóvenes, que se trata de molestias, por lo general, de moderadas a severas, con una alta frecuencia de aparición y de larga duración. Habitualmente se trata de cuadros crónicos. Estos problemas afectan a la calidad de vida de los jóvenes, más allá de lo que puede explicar la propia ENM. Los estudios revisados muestran que no solo la calidad de vida de los jóvenes se ve afectada por la presencia del dolor, también la de sus cuidadores. Abstract in english The aim of this paper is to review the available information on the experience of pain in children and adolescents with neuromuscular disease (NMD). In order to do this, we examined the MEDLINE and SCOPUS databases and located published articles on the subject until March 2012. After a thorough anal [...] ysis, we identified 33 articles that met the inclusion criteria. The analysis conducted shows that pain is a very common experience for these young people, usually moderate to severe, with a high frequency of occurrence and long lasting. In general, these are chronic conditions. These chronic pain problems affect the quality of life of young people, beyond what could be explained by the NMD alone. The reviewed studies show that pain not only negatively impacts the quality of life of young people, also that of their caregivers is at jeopardy.

M., López; J., Miró.

2013-06-01

291

RNA-targeted splice-correction therapy for neuromuscular disease.  

Science.gov (United States)

Splice-modulation therapy, whereby molecular manipulation of premessenger RNA splicing is engineered to yield genetic correction, is a promising novel therapy for genetic diseases of muscle and nerve-the prototypical example being Duchenne muscular dystrophy. Duchenne muscular dystrophy is the most common childhood genetic disease, affecting one in 3500 newborn boys, causing progressive muscle weakness, heart and respiratory failure and premature death. No cure exists for this disease and a number of promising new molecular therapies are being intensively studied. Duchenne muscular dystrophy arises due to mutations that disrupt the open-reading-frame in the DMD gene leading to the absence of the essential muscle protein dystrophin. Of all novel molecular interventions currently being investigated for Duchenne muscular dystrophy, perhaps the most promising method aiming to restore dystrophin expression to diseased cells is known as 'exon skipping' or splice-modulation, whereby antisense oligonucleotides eliminate the deleterious effects of DMD mutations by modulating dystrophin pre-messenger RNA splicing, such that functional dystrophin protein is produced. Recently this method was shown to be promising and safe in clinical trials both in The Netherlands and the UK. These trials studied direct antisense oligonucleotide injections into single peripheral lower limb muscles, whereas a viable therapy will need antisense oligonucleotides to be delivered systemically to all muscles, most critically to the heart, and ultimately to all other affected tissues including brain. There has also been considerable progress in understanding how such splice-correction methods could be applied to the treatment of related neuromuscular diseases, including spinal muscular atrophy and myotonic dystrophy, where defects of splicing or alternative splicing are closely related to the disease mechanism. PMID:20150322

Wood, Matthew J A; Gait, Michael J; Yin, Haifang

2010-04-01

292

Patient machine interface for the control of mechanical ventilation devices.  

Science.gov (United States)

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. PMID:24961620

Grave de Peralta, Rolando; Gonzalez Andino, Sara; Perrig, Stephen

2013-01-01

293

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

294

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

Science.gov (United States)

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

Sarkar, Nilanjan; Yun, Xiaoping; Kumar, Vijay

1994-01-01

295

Mechanism of controlling supersonic cavity oscillations using upstream mass injection  

Science.gov (United States)

The mechanism of controlling supersonic cavity oscillations using upstream mass injection is investigated by implicit large-eddy simulations of a turbulent flow (M? = 2.0, ReD = 105) past a rectangular cavity with a length-to-depth ratio of 2. The mass injection is simulated by specifying a vertical velocity profile of a jet ejecting steadily through a slot placed at the upstream of the cavity leading edge. The results show that the steady upstream mass injection produces significant attenuation of the cavity oscillations, and two primary mechanisms are demonstrated to be directly responsible for the noise suppression: lifting up of the cavity shear layer, and damping of the shear-layer instability. It is found that the case of low mass flow injection investigated is more effective in stabilizing the cavity shear layer than the high mass flow injection. A transition stage might exist between two well-developed oscillating modes, but "mode-switching" is not observed.

Li, Weipeng; Nonomura, Taku; Fujii, Kozo

2013-08-01

296

Translational control mechanisms in angiogenesis and vascular biology.  

Science.gov (United States)

Among the multiple modes of regulation of gene expression, translational control is arguably the least investigated and understood, and its role in vascular biology and pathobiology is not an exception. Here, we review recent studies that have revealed exciting translational regulatory phenomena and mechanisms involving novel RNA binding proteins and microRNA machinery in vascular biology. From these studies, the importance of translational regulation in angiogenesis, atherosclerosis, and blood pressure maintenance is beginning to emerge. We believe that the recent development of powerful techniques such as ribosome profiling and translating ribosome affinity purification (TRAP) will motivate and facilitate additional research in these areas. PMID:25786748

Yao, Peng; Eswarappa, Sandeepa M; Fox, Paul L

2015-05-01

297

Electromagnetic control rod drive mechanism, with reduced heat losses  

International Nuclear Information System (INIS)

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

298

Assessment of ventilatory neuromuscular drive in patients with obstructive sleep apnea  

Scientific Electronic Library Online (English)

Full Text Available The presence of abnormalities of the respiratory center in obstructive sleep apnea (OSA) patients and their correlation with polysomnographic data are still a matter of controversy. Moderately obese, sleep-deprived OSA patients presenting daytime hypersomnolence, with normocapnia and no clinical or [...] spirometric evidence of pulmonary disease, were selected. We assessed the ventilatory control and correlated it with polysomnographic data. Ventilatory neuromuscular drive was evaluated in these patients by measuring the ventilatory response (VE), the inspiratory occlusion pressure (P.1) and the ventilatory pattern (VT/TI, TI/TTOT) at rest and during submaximal exercise, breathing room air. These analyses were also performed after inhalation of a hypercapnic mixture of CO2 (DP.1/DPETCO2, DVE/DPETCO2). Average rest and exercise ventilatory response (VE: 12.2 and 32.6 l/min, respectively), inspiratory occlusion pressure (P.1: 1.5 and 4.7 cmH2O, respectively), and ventilatory pattern (VT/TI: 0.42 and 1.09 l/s; TI/TTOT: 0.47 and 0.46 l/s, respectively) were within the normal range. In response to hypercapnia, the values of ventilatory response (DVE/DPETCO2: 1.51 l min-1 mmHg-1) and inspiratory occlusion pressure (DP.1/DPETCO2: 0.22 cmH2O) were normal or slightly reduced in the normocapnic OSA patients. No association or correlation between ventilatory neuromuscular drive and ventilatory pattern, hypersomnolence score and polysomnographic data was found; however a significant positive correlation was observed between P.1 and weight. Our results indicate the existence of a group of normocapnic OSA patients who have a normal awake neuromuscular ventilatory drive at rest or during exercise that is partially influenced by obesity

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

1998-04-01

299

Assessment of ventilatory neuromuscular drive in patients with obstructive sleep apnea  

Directory of Open Access Journals (Sweden)

Full Text Available The presence of abnormalities of the respiratory center in obstructive sleep apnea (OSA patients and their correlation with polysomnographic data are still a matter of controversy. Moderately obese, sleep-deprived OSA patients presenting daytime hypersomnolence, with normocapnia and no clinical or spirometric evidence of pulmonary disease, were selected. We assessed the ventilatory control and correlated it with polysomnographic data. Ventilatory neuromuscular drive was evaluated in these patients by measuring the ventilatory response (VE, the inspiratory occlusion pressure (P.1 and the ventilatory pattern (VT/TI, TI/TTOT at rest and during submaximal exercise, breathing room air. These analyses were also performed after inhalation of a hypercapnic mixture of CO2 (DP.1/DPETCO2, DVE/DPETCO2. Average rest and exercise ventilatory response (VE: 12.2 and 32.6 l/min, respectively, inspiratory occlusion pressure (P.1: 1.5 and 4.7 cmH2O, respectively, and ventilatory pattern (VT/TI: 0.42 and 1.09 l/s; TI/TTOT: 0.47 and 0.46 l/s, respectively were within the normal range. In response to hypercapnia, the values of ventilatory response (DVE/DPETCO2: 1.51 l min-1 mmHg-1 and inspiratory occlusion pressure (DP.1/DPETCO2: 0.22 cmH2O were normal or slightly reduced in the normocapnic OSA patients. No association or correlation between ventilatory neuromuscular drive and ventilatory pattern, hypersomnolence score and polysomnographic data was found; however a significant positive correlation was observed between P.1 and weight. Our results indicate the existence of a group of normocapnic OSA patients who have a normal awake neuromuscular ventilatory drive at rest or during exercise that is partially influenced by obesity

L.R.A. Bittencourt

1998-04-01

300

Neuromuscular exercise improves functional performance in patients with severe hip osteoarthritis  

DEFF Research Database (Denmark)

Purpose. Exercise is regarded a cornerstone in the treatment of mild to moderate osteoarthritis (OA). However, little is known of the effects in patients with advanced and end-stage OA. The purpose was to evaluate the effect of neuromuscular exercise in patients with severe hip OA. Methods. Design. Randomized controlled trial (Clinicaltrials.gov identifier: NCT01003756). 84 patients, 51% female, mean age 68.6±7.8 years, BMI 28.7±4.7 scheduled for total hip replacement at Svendborg Community Hospital, Odense University Hospital, Denmark were included. Intervention. Participants were randomized to an eight-week neuromuscular exercise (NEMEX-TJR) intervention or care-as-usual (verbal and written preoperative information). Intervention was supervised and offered twice a week with each session lasting one hour. The program is considered feasible and safe in this patient group and previously described in detail. Assessments were carried out at baseline and within one week after the intervention. Outcomes. Functional performance: 20-m walk at maximal pace and 5 repeated chair stands timed. Muscle power: Unilateral multi-joint leg extension power and unilateral single-joint knee extension power evaluated with a leg extension press (Nottingham Power Rig, Nottingham University, Nottingham, UK) and a seated knee extension machine (Oemmebi, Moglia, Italy) adapted with a linear encoder (MuscleLab Power, Ergotest Technology, Langesund, Norway), respectively. Results. On average the intervention group attended 13±4 sessions (Table 1). In favor of the intervention group, the between-group difference was significant for 20-m walk (2.2 seconds, p=.009), chair stands (1.7 seconds, p=.022) and leg extension for the non operated leg (.17 W/kg, p=.049) (Table 2). Conclusion. Eight weeks neuromuscular exercise according to the NEMEX-TJR program improves functional performance and leg extension power in patients with severe OA of the hip joint.

Villadsen, Allan; Overgaard, SØren

301

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

302

On Mechanism of Plasma-shock-based Flow Control  

Science.gov (United States)

The mechanism of plasma-shock-based flow control was studied. Due to the high reduced electric field strength and peak power in the nanosecond discharge, a large quantity of high-energy electrons are produced. The quenching of the electronically excited states of N2, the dissociation of O2 and N2, and the recombination of molecular ions with electrons cause fast heating of local air near the electrode edge and fast air pressure rise, thus inducing shock waves. The effectiveness of using nanosecond discharge plasma aerodynamic actuation to improve flow separation control capability was validated at the freestream velocity of 150 m/s. Critical stall angle, lift and drag of NACA 0015 airfoil were measured with and without the nanosecond discharge plasma aerodynamic actuation in the wind tunnel experiments.

Wu, Y.; Li, Y. H.; Liang, H.; Jia, M.; Song, H. M.

2011-09-01

303

Effect of nicotine on neuromuscular transmission in mouse motor synapses.  

Science.gov (United States)

Nicotine (10 nM) inhibits rhythmic activity of the neuromuscular synapse in mice. This effect was prevented by alpha-cobratoxin and apamin. Hence, the effects of nicotine are realized via presynaptic neuronal nicotinic cholinoceptors and Ca(2+)-activated potassium channels. PMID:17369892

Balezina, O P; Fedorin, V V; Gaidukov, A E

2006-07-01

304

Neuromuscular Bandage: Neurophysiological Effects and the Role of Fascias  

Directory of Open Access Journals (Sweden)

Full Text Available During the last years, neuromuscular bandage, a therapeutic application created in 1979 by doctor Kenzo Kase has been introduced in the management of many disorders of the musculo-skeletal system and even more so in the treatment of neurological disorders; This therapeutic tool which consists of a self adhesive elastic bandage allows recovery of the injured party without diminishing its bodily function. According to the existing literature on the physiological effects of this therapeutic application in the body, you could say that there is consensus. However in this article the author wants to highlight the significant although little highlighted role played by the fas¬cias on the therapeutic effects of neuromuscular bandage, analyzing from a reflective perspective the analgesic, neuromechanical and circulatory effects, as fundamental effects of neuromuscular bandage and fascias in the same function, trying to bring a global understanding on the way they relate to all connective tissues, aspects that are of great importance for the proper evaluation of alterations and prescription of neuromuscular bandage

Ximena María Villota Chicaíza

2014-05-01

305

The sagital balance in idiopatic and neuromuscular scoliosis  

Scientific Electronic Library Online (English)

Full Text Available OBJECTIVES: To describe and compare the distribution of spinopelvic parameters (SPP) in a Brazilian population with idiopathic scoliosis (IS) and neuromuscular scoliosis (NMS), and evaluate the association between pelvic incidence (PI) and lumbar lordosis (LL). METHOD: Medical records investig [...] ation was performed. Sagital balance angles were measured in patients with neuromuscular and idiopathic scoliosis. RESULTS: IS sample means (in degrees): PI 55.55; Sacral Slope (SS) 45.35; Pelvic Tilt (PT) 10.19; Lumbar Lordosis (LL) 43.48; and Thoracic Kyphosis (TK) 32.10. In NMS: PI 53.77; SS 42.31; PT 11.46; LL 49.46; and TK 45.69. No statistically significant differences in PEP distribution were found between the two types of scoliosis (p=0,057). The association between pelvic incidence and lumbar lordosis is low among idiopathic scoliosis (R=0,074) and neuromuscular scoliosis (R=0,274). CONCLUSION: PEP measurements in a Brazilian population of idiopathic scoliosis and neuromuscular scoliosis patients are similar to those in the international literature and do not differ statistically between them. The association between LL and PI could not be assessed in this study. Level of Evidence IV, Case Series.

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

2014-07-01

306

Diagnostic value of CT scanning in neuromuscular diseases  

International Nuclear Information System (INIS)

The diagnosis of myopathies has become easier since the CT technique is available. In this article the possibilities of CT for diagnostic procedures of neuromuscular diseases are pointed out. Density measurements increase differentiation of atrophy or hypertrophy of muscles as well as other pathological changes. (orig.)

307

Uranium dioxide sintering Kinetics and mechanisms under controlled oxygen potentials  

International Nuclear Information System (INIS)

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

308

A Cell-Level Mechanism of Contrast Gain Control  

CERN Document Server

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

Schumacher, Linus J

2013-01-01

309

Discrete Mechanics and Optimal Control for Space Trajectory Design  

Science.gov (United States)

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

Moore, Ashley

310

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

Directory of Open Access Journals (Sweden)

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

C. Pelizzari

2008-02-01

311

Treatment of a patient with posterior cortical atrophy (PCA) with chiropractic manipulation and Dynamic Neuromuscular Stabilization (DNS): A case report  

Science.gov (United States)

Objective: Posterior cortical atrophy (PCA) is a rare progressive neurodegenerative syndrome which unusual symptoms include deficits of balance, bodily orientation, chronic pain syndrome and dysfunctional motor patterns. Current research provides minimal guidance on support, education and recommended evidence-based patient care. This case reports the utilization of chiropractic spinal manipulation, dynamic neuromuscular stabilization (DNS), and other adjunctive procedures along with medical treatment of PCA. Clinical features: A 54-year-old male presented to a chiropractic clinic with non-specific back pain associated with visual disturbances, slight memory loss, and inappropriate cognitive motor control. After physical examination, brain MRI and PET scan, the diagnosis of PCA was recognized. Intervention and Outcome: Chiropractic spinal manipulation and dynamic neuromuscular stabilization were utilized as adjunctive care to conservative pharmacological treatment of PCA. Outcome measurements showed a 60% improvement in the patient’s perception of health with restored functional neuromuscular pattern, improvements in locomotion, posture, pain control, mood, tolerance to activities of daily living (ADLs) and overall satisfactory progress in quality of life. Yet, no changes on memory loss progression, visual space orientation, and speech were observed. Conclusion: PCA is a progressive and debilitating condition. Because of poor awareness of PCA by physicians, patients usually receive incomplete care. Additional efforts must be centered on the musculoskeletal features of PCA, aiming enhancement in quality of life and functional improvements (FI). Adjunctive rehabilitative treatment is considered essential for individuals with cognitive and motor disturbances, and manual medicine procedures may be consider a viable option. PMID:25729084

Francio, Vinicius T.; Boesch, Ron; Tunning, Michael

2015-01-01

312

Basic mechanisms controlling the sweeping efficiency of propagating current sheets  

Science.gov (United States)

The basic mechanisms controlling the sweeping efficiency of propagating current sheets are investigated through experiments and analytical modelling. The sweeping efficiency of a current sheet in a parallel plate gas-fed pulsed plasma accelerator is defined as the ratio of the current sheet mass to the total available propellant mass. Permeability of neutrals through the sheet, and leakage of mass out of the sheet and into a cathode wake, decrease the sweeping efficiency. The sweeping efficiency of current sheets in argon, neon, helium and hydrogen propellants at different initial pressures was determined through measurements of sheet velocity with high speed photography and of sheet mass with laser interferometry. The mechanism that controls the sweeping efficiency of propagating current sheets was found to be an interplay of two processes: the flux of mass entering the sheet and the leakage of mass at the cathode, with the former dependent on the degree of permeability and the latter dependent on the level of ion current as determined by the ion Hall parameter.

Berkery, J. W.; Choueiri, E. Y.

2006-02-01

313

Mechanisms and Evolution of Control Logic in Prokaryotic Transcriptional Regulation  

Science.gov (United States)

Summary: A major part of organismal complexity and versatility of prokaryotes resides in their ability to fine-tune gene expression to adequately respond to internal and external stimuli. Evolution has been very innovative in creating intricate mechanisms by which different regulatory signals operate and interact at promoters to drive gene expression. The regulation of target gene expression by transcription factors (TFs) is governed by control logic brought about by the interaction of regulators with TF binding sites (TFBSs) in cis-regulatory regions. A factor that in large part determines the strength of the response of a target to a given TF is motif stringency, the extent to which the TFBS fits the optimal TFBS sequence for a given TF. Advances in high-throughput technologies and computational genomics allow reconstruction of transcriptional regulatory networks in silico. To optimize the prediction of transcriptional regulatory networks, i.e., to separate direct regulation from indirect regulation, a thorough understanding of the control logic underlying the regulation of gene expression is required. This review summarizes the state of the art of the elements that determine the functionality of TFBSs by focusing on the molecular biological mechanisms and evolutionary origins of cis-regulatory regions. PMID:19721087

van Hijum, Sacha A. F. T.; Medema, Marnix H.; Kuipers, Oscar P.

2009-01-01

314

Mechanism of controlled release kinetics from medical devices  

Scientific Electronic Library Online (English)

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

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

2010-06-01

315

Central chemoreceptors and neural mechanisms of cardiorespiratory control  

Scientific Electronic Library Online (English)

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

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

2011-09-01

316

Central chemoreceptors and neural mechanisms of cardiorespiratory control  

Directory of Open Access Journals (Sweden)

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

T.S. Moreira

2011-09-01

317

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

Science.gov (United States)

In this work, we have examined the neuromuscular activity of Micrurus laticollaris (Mexican coral snake) venom (MLV) in vertebrate isolated nerve-muscle preparations. In chick biventer cervicis preparations, the MLV induced an irreversible concentration- and time-dependent (1-30 µg/mL) neuromuscular blockade, with 50% blockade occurring between 8 and 30 min. Muscle contractures evoked by exogenous acetylcholine were completely abolished by MLV, whereas those of KCl were also significantly altered (86% ± 11%, 53% ± 11%, 89% ± 5% and 89% ± 7% for one, three, 10 and 30 µg of venom/mL, respectively; n = 4; p phrenic nerve-diaphragm preparations, MLV (1-10 µg/mL) promoted a slight increase in the amplitude of twitch-tension (3 µg/mL), followed by neuromuscular blockade (n = 4); the highest concentration caused complete inhibition of the twitches (time for 50% blockade = 26 ± 3 min), without exhibiting a previous neuromuscular facilitation. The venom (3 µg/mL) induced a biphasic modulation in the frequency of miniature end-plate potentials (MEPPs)/min, causing a significant increase after 15 min, followed by a decrease after 60 min (from 17 ± 1.4 (basal) to 28 ± 2.5 (t15) and 12 ± 2 (t60)). The membrane resting potential of mouse diaphragm preparations pre-exposed or not to d-tubocurarine (5 µg/mL) was also significantly less negative with MLV (10 µg/mL). Together, these results indicate that M. laticollaris venom induces neuromuscular blockade by a combination of pre- and post-synaptic activities. PMID:24445448

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

2014-01-01

318

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

Science.gov (United States)

In this work, we have examined the neuromuscular activity of Micrurus laticollaris (Mexican coral snake) venom (MLV) in vertebrate isolated nerve-muscle preparations. In chick biventer cervicis preparations, the MLV induced an irreversible concentration- and time-dependent (1–30 µg/mL) neuromuscular blockade, with 50% blockade occurring between 8 and 30 min. Muscle contractures evoked by exogenous acetylcholine were completely abolished by MLV, whereas those of KCl were also significantly altered (86% ± 11%, 53% ± 11%, 89% ± 5% and 89% ± 7% for one, three, 10 and 30 µg of venom/mL, respectively; n = 4; p < 0.05). In mouse phrenic nerve-diaphragm preparations, MLV (1–10 µg/mL) promoted a slight increase in the amplitude of twitch-tension (3 µg/mL), followed by neuromuscular blockade (n = 4); the highest concentration caused complete inhibition of the twitches (time for 50% blockade = 26 ± 3 min), without exhibiting a previous neuromuscular facilitation. The venom (3 µg/mL) induced a biphasic modulation in the frequency of miniature end-plate potentials (MEPPs)/min, causing a significant increase after 15 min, followed by a decrease after 60 min (from 17 ± 1.4 (basal) to 28 ± 2.5 (t15) and 12 ± 2 (t60)). The membrane resting potential of mouse diaphragm preparations pre-exposed or not to d-tubocurarine (5 µg/mL) was also significantly less negative with MLV (10 µg/mL). Together, these results indicate that M. laticollaris venom induces neuromuscular blockade by a combination of pre- and post-synaptic activities. PMID:24445448

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

2014-01-01

319

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

Directory of Open Access Journals (Sweden)

Full Text Available In this work, we have examined the neuromuscular activity of Micrurus laticollaris (Mexican coral snake venom (MLV in vertebrate isolated nerve-muscle preparations. In chick biventer cervicis preparations, the MLV induced an irreversible concentration- and time-dependent (1–30 µg/mL neuromuscular blockade, with 50% blockade occurring between 8 and 30 min. Muscle contractures evoked by exogenous acetylcholine were completely abolished by MLV, whereas those of KCl were also significantly altered (86% ± 11%, 53% ± 11%, 89% ± 5% and 89% ± 7% for one, three, 10 and 30 µg of venom/mL, respectively; n = 4; p < 0.05. In mouse phrenic nerve-diaphragm preparations, MLV (1–10 µg/mL promoted a slight increase in the amplitude of twitch-tension (3 µg/mL, followed by neuromuscular blockade (n = 4; the highest concentration caused complete inhibition of the twitches (time for 50% blockade = 26 ± 3 min, without exhibiting a previous neuromuscular facilitation. The venom (3 µg/mL induced a biphasic modulation in the frequency of miniature end-plate potentials (MEPPs/min, causing a significant increase after 15 min, followed by a decrease after 60 min (from 17 ± 1.4 (basal to 28 ± 2.5 (t15 and 12 ± 2 (t60. The membrane resting potential of mouse diaphragm preparations pre-exposed or not to d-tubocurarine (5 µg/mL was also significantly less negative with MLV (10 µg/mL. Together, these results indicate that M. laticollaris venom induces neuromuscular blockade by a combination of pre- and post-synaptic activities.

Alejandro Carbajal-Saucedo

2014-01-01

320

14 CFR 29.923 - Rotor drive system and control mechanism tests.  

Science.gov (United States)

...2010-01-01 2010-01-01 false Rotor drive system and control mechanism tests. 29.923...TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.923 Rotor drive system and control mechanism tests. (a)...

2010-01-01

321

14 CFR 27.923 - Rotor drive system and control mechanism tests.  

Science.gov (United States)

...2010-01-01 2010-01-01 false Rotor drive system and control mechanism tests. 27.923...NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.923 Rotor drive system and control mechanism tests....

2010-01-01

322

Rotating stall mechanism and stability control in the pump flows  

International Nuclear Information System (INIS)

Investigations based on experimental measurements and flow dynamics analysis have been completed to reveal the mechanism of flow separations in the pump flow. The possible flow separation including the rotating stall in the vaned diffuser under the normal flow condition has been confirmed to be merely a diffuser effect and caused by the oversized expansion angle of the diffuser. The part load flow separation of both the stationary and the non-stationary character has been identified to have its occurrence origin in the flow at the impeller inlet. The mechanism of the flow separation at the impeller inlet has been revealed with respect to the built-up of a flow dynamical barrier on the shroud side. It exactly explains the coincidence of the flow separation at the impeller inlet and that at the impeller outlet. To quantify the onset of the flow separation, a hypothesis is established based on the revealed mechanism. This has been satisfactorily validated by the test based on the flow visualization, pressure measurements and LDA applications. The method for stability control of the pump flows with effective suppression of the flow separation has also been presented.

323

Auction Mechanism to Allocate Air Traffic Control Slots  

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

Raffarin, Marianne

2003-01-01

324

Controlled nerve ablation with direct current: parameters and mechanisms.  

Science.gov (United States)

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

Ravid, Einat; Prochazka, Arthur

2014-11-01

325

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

Science.gov (United States)

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

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

2014-09-19

326

Envelhecimento e treinamento de potência: aspectos neuromusculares e funcionais / Aging and power training: neuromuscular and functional aspects  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A proporção de idosos na população é cada vez maior nos diferentes países, tornado fundamental o seu estudo em diferentes perspectivas. Desta forma, o objetivo da presente revisão é compreender como o envelhecimento atua no sistema neuromuscular, em especial na força muscular, e como este declínio a [...] tua nos aspectos funcionais, ou seja, nas tarefas do dia a dia. Além disso, será abordado como o treinamento de força, em específico visando à melhora da potência muscular, pode ser uma estratégia segura e efetiva no combate aos efeitos adversos do envelhecimento no sistema neuromuscular. Abstract in english The proportion of elderly in the population is growing in different countries, which makes essential to examine this part of the population in different perspectives. In this way, the objective of this review is to understand how aging affects the neuromuscular system, especially muscle strength, an [...] d how this decline works on functional aspects, i.e. on everyday tasks. In addition, it is investigated how strength training, specifically aimed at improving muscle strength, can be a safe and effective strategy in combating the adverse effects of aging on neuromuscular system.

Carlos Leandro, Tiggemann; Caroline Pieta, Dias; Matias, Noll; Maira Cristina Wolf, Schoenell; Luiz Fernando Martins, Kruel.

2013-06-01

327

Aging interferes central control mechanism for eccentric muscle contraction  

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

Wan X. Yao

2014-05-01

328

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

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

Juliana Noda Bechara

1999-03-01

329

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

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Full Text Available In a polysomnography study of 32 neuromuscular patients - 22 with a form of muscular dystrophy, 3 with a form of congenital myopathy, 4 with a form of spinal muscular atrophy, 1 with a recurrent form of polymyositis and 1 with osteogenesis imperfecta syndrome - of which 21 were nonambulatory, we observed sleep related respiratory disturbances represented by: drops in oxygen saturation (SaO2, cardiac arrythmia, sleep disruption, apneas, tachypnea, tachycardia and snoring. Nine out of the cohort of 32 patients presented with significant desaturations periods. These patients presented with an associated restrictive syndrome and thoracic deformities, some with tachypnea and/or SaO2 below 90% during wakefulness. In this group, snoring was observed in those patients with a form of muscular dystrophy while tachypnea was observed in patients who presented the highest desaturations levels. Sleep quantification revealed an increase of stage 1 sleep coupled with a decrease or even total absence of REM sleep. This is, we believe, a likely consequence of episodic desaturations that may accompany sleep hypoventilation which is potentialised during REM sleep stage.Estudando 32 pacientes com doenças neuromusculares -22 com forma de distrofia muscular, 3 com forma de miopatia congênita, 4 com forma de atrofia muscular espinal, 1 com forma recorrente de polimiosite e 1 com síndrome de osteogenesis imperfecta - dos quais 21 estavam impossibilitados de deambulação, distúrbios respiratórios relacionados ao sono foram observados sob forma dessaturação da oxi-hemogloblina, arritmia cardíaca, taquipnéia, taquicardia e roncos. Nove desses 32 pacientes apresentaram períodos de dessaturação de oxi-hemoglobina maiores que 4% em relação aos níveis obtidos em vigília e repouso. Esse grupo de pacientes era caracterizado por apresentar síndrome respiratória restritiva associada a deformidade torácica (principalmente escoliose. Alguns apresentaram taquipnéia e/ou saturação da oxi-hemoglobina abaixo de 90% durante o repouso e em vigília. Neste grupo, roncos foram observados principalmente nos pacientes com forma de distrofia muscular, enquanto a taquipnéia foi observada sobretudo nos pacientes com os maiores níveis de dessaturação. A quantificação do sono mostrou aumento na porcentagem do estado 1 do sono associada a diminuição ou mesmo ausência do estado do sono paradoxal. Isso nos leva a crer em um provável mecanismo de proteção consequente à potencialização da hipoventilação observada durante o estado de sono paradoxal, em que os maiores níveis de dessaturação são observados.

Márcia Pradella

1994-12-01

330

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

Scientific Electronic Library Online (English)

Full Text Available Estudando 32 pacientes com doenças neuromusculares -22 com forma de distrofia muscular, 3 com forma de miopatia congênita, 4 com forma de atrofia muscular espinal, 1 com forma recorrente de polimiosite e 1 com síndrome de osteogenesis imperfecta - dos quais 21 estavam impossibilitados de deambulação [...] , distúrbios respiratórios relacionados ao sono foram observados sob forma dessaturação da oxi-hemogloblina, arritmia cardíaca, taquipnéia, taquicardia e roncos. Nove desses 32 pacientes apresentaram períodos de dessaturação de oxi-hemoglobina maiores que 4% em relação aos níveis obtidos em vigília e repouso. Esse grupo de pacientes era caracterizado por apresentar síndrome respiratória restritiva associada a deformidade torácica (principalmente escoliose). Alguns apresentaram taquipnéia e/ou saturação da oxi-hemoglobina abaixo de 90% durante o repouso e em vigília. Neste grupo, roncos foram observados principalmente nos pacientes com forma de distrofia muscular, enquanto a taquipnéia foi observada sobretudo nos pacientes com os maiores níveis de dessaturação. A quantificação do sono mostrou aumento na porcentagem do estado 1 do sono associada a diminuição ou mesmo ausência do estado do sono paradoxal. Isso nos leva a crer em um provável mecanismo de proteção consequente à potencialização da hipoventilação observada durante o estado de sono paradoxal, em que os maiores níveis de dessaturação são observados. Abstract in english In a polysomnography study of 32 neuromuscular patients - 22 with a form of muscular dystrophy, 3 with a form of congenital myopathy, 4 with a form of spinal muscular atrophy, 1 with a recurrent form of polymyositis and 1 with osteogenesis imperfecta syndrome - of which 21 were nonambulatory, we obs [...] erved sleep related respiratory disturbances represented by: drops in oxygen saturation (SaO2), cardiac arrythmia, sleep disruption, apneas, tachypnea, tachycardia and snoring. Nine out of the cohort of 32 patients presented with significant desaturations periods. These patients presented with an associated restrictive syndrome and thoracic deformities, some with tachypnea and/or SaO2 below 90% during wakefulness. In this group, snoring was observed in those patients with a form of muscular dystrophy while tachypnea was observed in patients who presented the highest desaturations levels. Sleep quantification revealed an increase of stage 1 sleep coupled with a decrease or even total absence of REM sleep. This is, we believe, a likely consequence of episodic desaturations that may accompany sleep hypoventilation which is potentialised during REM sleep stage.

Márcia, Pradella.

1994-12-01

331

The effects of band exercise using proprioceptive neuromuscular facilitation on muscular strength in lower extremity  

Science.gov (United States)

The purpose of this study was to examine whether a six-week elastic band exercise program using proprioceptive neuromuscular facilitation (PNF) can increase isotonic strength of abductor muscles in the lower extremity. Twenty-eight healthy students from S university were divided into an experimental group and control group. Each group was participated in pre and post-measurement in isotonic strength using an isotonic analyzer, En-treeM. Experimental group performed elastic band exercise using PNF pattern for a six-weeks, in contrast, control group did not take any exercise. In the results of this study, isotonic strength measurements of abductor muscles in lower extremity in experimental group were significantly different after exercise, but control group did not show any significant changes. Therefore, we hope that resistive exercise would be very valuable for healthy people as well as the old people with weakened muscle strength.

Rhyu, Hyun-Seung; Kim, Su-Hyun; Park, Hye-Sang

2015-01-01

332

Efeito de um programa de treinamento de facilitação neuromuscular proprioceptiva sobre a mobilidade torácica / Effect of a training program based on proprioceptive neuromuscular facilitation onto thoracic mobility  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A proposta deste estudo foi analisar o efeito de um programa de treinamento de membros superiores baseado nas técnicas de facilitação neuromuscular proprioceptiva (FNP) sobre a mobilidade torácica. Foram estudadas 24 voluntárias sedentárias, idade 22,9 ± 2,9 anos, divididas em grupo controle (GC), q [...] ue não participou do treinamento, e grupo treinado (GT). O protocolo de treinamento físico foi constituído por um programa de exercícios de FNP, realizado três vezes por semana, durante quatro semanas. Os dois grupos foram submetidos à avaliação da mobilidade torácica por meio de cirtometria, antes e após o período de treinamento. Os dados colhidos foram analisados estatisticamente, com nível de significância ? = 5%. Os valores da cirtometria axilar e xifoideana do GC antes e após o período de intervenção não apresentaram alterações significativas (p>0,05). No GT os valores das variáveis foram significantemente maiores após a intervenção (p Abstract in english The purpose of this study was to analyse the effect of an upper limb training program based on proprioceptive neuromuscular facilitation (PNF) techniques on thoracic mobility. The study was carried out with 24 sedentary female volunteers, aged 22.9±2.9 years. Participants were divided into a control [...] group (CG), who did not perform any exercise, and a trained group (TG), submitted to training. The physical training protocol consisted of a PNF exercise program, three times a week for four weeks. The two groups were assessed as to thoracic mobility by means of cirtometry before and after the training period. Data were statistically analysed and significance level set at ?=5%. In CG, initial axillary and xiphoid cirtometry values showed no significant differences when compared to data obtained on the final evaluation (p>0.05). TG measures, in turn, were significantly higher after the training program (p

Marlene Aparecida, Moreno; Ester da, Silva; Roberta Silva, Zuttin; Mauro, Gonçalves.

2009-06-01

333

Chemo-mechanical control of neural stem cell differentiation  

Science.gov (United States)

Cellular processes such as adhesion, proliferation, and differentiation are controlled in part by cell interactions with the microenvironment. Cells can sense and respond to a variety of stimuli, including soluble and insoluble factors (such as proteins and small molecules) and externally applied mechanical stresses. Mechanical properties of the environment, such as substrate stiffness, have also been suggested to play an important role in cell processes. The roles of both biochemical and mechanical signaling in fate modification of stem cells have been explored independently. However, very few studies have been performed to study well-controlled chemo-mechanotransduction. The objective of this work is to design, synthesize, and characterize a chemo-mechanical substrate to encourage neuronal differentiation of C17.2 neural stem cells. In Chapter 2, Polyacrylamide (PA) gels of varying stiffnesses are functionalized with differing amounts of whole collagen to investigate the role of protein concentration in combination with substrate stiffness. As expected, neurons on the softest substrate were more in number and neuronal morphology than those on stiffer substrates. Neurons appeared locally aligned with an expansive network of neurites. Additional experiments would allow for statistical analysis to determine if and how collagen density impacts C17.2 differentiation in combination with substrate stiffness. Due to difficulties associated with whole protein approaches, a similar platform was developed using mixed adhesive peptides, derived from fibronectin and laminin, and is presented in Chapter 3. The matrix elasticity and peptide concentration can be individually modulated to systematically probe the effects of chemo-mechanical signaling on differentiation of C17.2 cells. Polyacrylamide gel stiffness was confirmed using rheological techniques and found to support values published by Yeung et al. [1]. Cellular growth and differentiation were assessed by cell counts, immunocytochemistry (ICC), and neurite measurements. Data indicates that chemo-mechanical signaling is highly combinatorial in directing differentiation of C17.2s along a neuronal lineage in vitro. Chapter 4 discusses the design, synthesis, and characterization of a novel nanomaterial platform to investigate ligand-receptor binding. PEGylated nanoparticles were successfully synthesized and found to be relatively homogenous in size and morphology, as observed by transmission electron microscopy. However, successful binding of RGD peptide to the nanoparticle was not confirmed. Finally, a method for proteomic analysis of the C17.2 secretome is discussed in Chapter 5. Secreted proteins are of great importance as they can both influence cell behaviors as well as act as biomarkers of differentiation. Methods have been selected and optimized for protein extraction and two dimensional gel electrophoresis to be followed by mass spectrometry and protein identification. A temporal analysis of unique proteins expressed by C17.2s will result in a differentiation timeline. Deducing the dynamics of neuronal cell secretions will greatly contribute to the characterization of the C17.2 cell line and improve its relevance as a neural stem cell model. Overall, results illustrate the importance of chemical and mechanical cues in manipulating neural stem cell fate. These material platforms in combination with the further characterization of the C17.2 neural stem cells could have a great impact in the fields of neuronal biology, translational therapeutics, and pharmaceutical research.

Geishecker, Emily R.

334

Method of controlling moving-coil type control rod driving mechanisms  

International Nuclear Information System (INIS)

Purpose: To enable solenoid plungers to sufficiently follow after abrupt changes of moving speed of moving-coils in nuclear reactors. Method: In a control circuit for moving-coil type control rod driving mechanisms of nuclear reactors, the velocity of a driving device for the moving-coils is detected by a velocity detector to control the velocity change of exciting currents in the coils depending on a velocity instruction signal. Since the velocity change of the coil exciting current varies depending on the change in the velocity instruction signal, the solenoid plunger can smoothly follow after the moving coils electromagnetically coupled therewith, and the deviation between the moving-coils and the solenoid plunger, that is, the driving axis can be minimized. Accordingly, smooth reactor control can be attained. (Takahashi, M.)

335

The differential effects of PNF versus passive stretch conditioning on neuromuscular performance.  

Science.gov (United States)

The effects of flexibility conditioning on neuromuscular and sensorimotor performance were assessed near to full knee extension (25°). Eighteen males who were randomly assigned into two groups underwent eight weeks (three-times per week) of flexibility conditioning (hip region/knee flexor musculature; dominant limb) involving either proprioceptive neuromuscular facilitation (PNF) (n=9) or passive stretching (PASS) (n=9). Both modes of flexibility conditioning are popular within contemporary exercise and clinical settings and have demonstrated efficacy in improving range of motion. The contralateral limb and a prior 'no exercise' condition were used as controls. The PNF and PASS modes of conditioning improved passive hip flexibility to a similar extent (mean 19.3% vs. baseline, intervention limb, pPNF (PASS: 10.8% and 16.9% lengthening of EMDV and EMDE, respectively vs. PNF: 3.2% and 6.2%, pPNF conditioning suggests a preserved capability for rapid muscle activation, which is important in the maintenance of dynamic joint stability. That PNF was also equally efficacious in flexibility conditioning would suggest that this mode of flexibility training should be used over passive to help preserve dynamic joint stability capabilities at this extended and vulnerable joint position. PMID:23688197

Minshull, Claire; Eston, Roger; Bailey, Andrea; Rees, David; Gleeson, Nigel

2014-01-01

336

Assessment of neuromuscular function after different strength training protocols using tensiomyography.  

Science.gov (United States)

The purpose of the study was to analyse tensiomyography (TMG) sensitivity to changes in muscle force and neuromuscular function of the muscle rectus femoris (RF) using TMG muscle properties after five different lower-limb strength training protocols (MS = Multiple Sets; DS = Drop Sets; EO = Eccentric Overload; FW = Flywheel; PL = Plyometrics). After baseline measurements, 14 male strength trained athletes completed one squat training protocol per week over a five-week period in a randomized controlled order. Maximal voluntary isometric contraction (MVIC), TMG measurements of maximal radial displacement of the muscle belly (Dm), contraction time between 10 and 90% of Dm (Tc) as well as mean muscle contraction velocities from the beginning until 10% (V10), and 90% of Dm (V90) were analysed up to 0.5 hours (post-train), 24 hours (post-24) and 48 hours (post-48) after the training interventions. Significant ANOVA main effects for measurement points were found for all TMG contractile properties and MVIC (p muscle properties are sensitive to changes in muscle force and different lower-limb strength training protocols lead to changes in neuromuscular function of RF. In addition, those protocols involving high and eccentric load, and a high total time under tension may induce higher changes in TMG muscle properties. PMID:25474337

De Paula Simola, Rauno Alvaro; Harms, Nico; Raeder, Christian; Kellmann, Michael; Meyer, Tim; Pfeiffer, Mark; Ferrauti, Alexander

2014-12-01

337

Control of Mechanical Systems with Dry Friction / Control de sistemas mecánicos con fricción seca  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Se propone una estrategia de diseño de un controlador dinámico continuo para regular una clase de sistemas mecánicos totalmente actuados con fricción seca. Se demuestra que el control elimina el error en estado estacionario y que es robusto frente a cierto tipo de incertidumbres en los parámetros de [...] l sistema. Se propone también un método sencillo para calcular los parámetros del controlador. Además, se describe la aplicación de este resultado al control de sistemas subactuados de 2 grados de libertad, con fricción seca en la articulación no actuada. En este caso, el objetivo de control es regular la variable no actuada, manteniendo limitadas las amplitudes de la posición y de la velocidad de la articulación actuada. El desempeño del controlador propuesto se ilustra con resultados numéricos y experimentales. Abstract in english A technique to design a dynamic continuous controller to regulate a class of full-actuated mechanical systems with dry friction is proposed. It is shown that the control eliminates the steady-state error and is robust with respect to parameter uncertainties. A simple method to find the parameters of [...] the controller is also proposed. Moreover, an application of this result to control a 2-DOF underactuated mechanical system with dry friction in the non-actuated joint is described. Here, the control objective is to regulate the non-actuated variable while the position and speed of the actuated joint remain bounded. Performance issues of the developed synthesis are illustrated with numerical and experimental results.

Roque, Martínez; Joaquín, Álvarez.

2012-03-01

338

Brainstem mechanisms controlling cardiovascular reflexes in channel catfish.  

Science.gov (United States)

Microinjections of kynurenic acid and kainic acid into the general visceral nucleus (nGV), homologous to the mammalian nucleus tractus solitarius of the medulla, in anesthestized, spontaneously breathing catfish were used to identify central areas and mechanisms controlling resting normoxic heart rate and blood pressure and the cardiovascular responses to hypoxia. Kynurenic acid, an antagonist of ionotropic glutamate receptors, significantly reduced resting normoxic heart rate but did not block the bradycardia associated with aquatic hypoxia. Kainic acid (an excitotoxic glutamatergic receptor agonist) also significantly reduced normoxic heart rate, but blocked the hypoxia-induced bradycardia. Neither kynurenic acid nor kainic acid microinjections affected blood pressure in normoxia or hypoxia. The results of this study indicate that glutamatergic receptors in the nGV are involved in the maintenance of resting heart rate and the destruction of these neurons with kainic acid abolishes the bradycardia associated with aquatic hypoxia. PMID:24434806

Turesson, J; Hedrick, M S; Sundin, L; Burleson, M L

2014-04-01

339

Mechanical control of a microrod-resonator optical frequency comb  

CERN Document Server

Robust control and stabilization of optical frequency combs enables an extraordinary range of scientific and technological applications, including frequency metrology at extreme levels of precision, novel spectroscopy of quantum gases and of molecules from visible wavelengths to the far infrared, searches for exoplanets, and photonic waveform synthesis. Here we report on the stabilization of a microresonator-based optical comb (microcomb) by way of mechanical actuation. This represents an important step in the development of microcomb technology, which offers a pathway toward fully-integrated comb systems. Residual fluctuations of our 32.6 GHz microcomb line spacing reach a record stability level of $5\\times10^{-15}$ for 1 s averaging, thereby highlighting the potential of microcombs to support modern optical frequency standards. Furthermore, measurements of the line spacing with respect to an independent frequency reference reveal the effective stabilization of different spectral slices of the comb with a $&...

Papp, Scott B; Diddams, Scott A

2012-01-01

340

Bacterial cell curvature through mechanical control of cell growth  

DEFF Research Database (Denmark)

The cytoskeleton is a key regulator of cell morphogenesis. Crescentin, a bacterial intermediate filament-like protein, is required for the curved shape of Caulobacter crescentus and localizes to the inner cell curvature. Here, we show that crescentin forms a single filamentous structure that collapses into a helix when detached from the cell membrane, suggesting that it is normally maintained in a stretched configuration. Crescentin causes an elongation rate gradient around the circumference of the sidewall, creating a longitudinal cell length differential and hence curvature. Such curvature can be produced by physical force alone when cells are grown in circular microchambers. Production of crescentin in Escherichia coli is sufficient to generate cell curvature. Our data argue for a model in which physical strain borne by the crescentin structure anisotropically alters the kinetics of cell wall insertion to produce curved growth. Our study suggests that bacteria may use the cytoskeleton for mechanical control of growth to alter morphology

Cabeen, M.; Charbon, Godefroid

2009-01-01

341

The effect of a Lucia jig for 30 minutes on neuromuscular re-programming, in normal subjects  

Directory of Open Access Journals (Sweden)

Full Text Available The Lucia jig is a technique that promotes neuromuscular reprogramming of the masticatory system and allows the stabilization of the mandible without the interference of dental contacts, maintaining the mandible position in harmonic condition with the musculature in normal subjects or in patients with temporomandibular dysfunction (TMD. This study aimed to electromyographically analyze the activity (RMS of the masseter and temporal muscles in normal subjects (control group during the use of an anterior programming device, the Lucia jig, in place for 0, 5, 10, 20 and 30 minutes to demonstrate its effect on the stomatognathic system. Forty-two healthy dentate individuals (aged 21 to 40 years with normal occlusion and without parafunctional habits or temporomandibular dysfunction (RDC/TMD were evaluated on the basis of the electromyographic activity of the masseter and temporal muscles before placement of a neuromuscular re-programming device, the Lucia jig, on the upper central incisors. There were no statistically significant differences (p < 0.05 in the electromyographic activity of the masticatory muscles in the different time periods. The Lucia jig changed the electromyographic activity by promoting a neuromuscular reprogramming. In most of the time periods, it decreased the activation of the masticatory muscles, showing that this device has wide applicability in dentistry. The use of a Lucia jig over 0, 5, 10, 15, 20 and 30 minutes did not promote any statistically significant increase in muscle activity despite differences in the data, thus showing that this intra-oral device can be used in dentistry.

Mariangela Salles Pereira Nassar

2012-12-01

342

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

Science.gov (United States)

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). Histochemical staining and light microscopy were used to assess adaptations of myofibers to chronic overload. Results demonstrate that NMJs of young adult and aged muscles did not undergo morphological remodeling as a result of four weeks of chronic overload. In contrast, myofibers of young and aged rats displayed significant (P <0.05), but similar hypertrophy (~18%) following that four week intervention. In both age groups, however, this hypertrophy was detected in the plantaris, but not the soleus. These data indicate that moderate aging (the equivalent of 65 years in human lifetime) does not modify the sensitivity of the neuromuscular system to chronic overload. PMID:17720323

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

2007-01-01

343

A bimodular mechanism of calcium control in eukaryotes  

DEFF Research Database (Denmark)

Calcium ions (Ca(2+)) have an important role as secondary messengers in numerous signal transduction processes, and cells invest much energy in controlling and maintaining a steep gradient between intracellular (?0.1-micromolar) and extracellular (?2-millimolar) Ca(2+) concentrations. Calmodulin-stimulated calcium pumps, which include the plasma-membrane Ca(2+)-ATPases (PMCAs), are key regulators of intracellular Ca(2+) in eukaryotes. They contain a unique amino- or carboxy-terminal regulatory domain responsible for autoinhibition, and binding of calcium-loaded calmodulin to this domain releases autoinhibition and activates the pump. However, the structural basis for the activation mechanism is unknown and a key remaining question is how calmodulin-mediated PMCA regulation can cover both basal Ca(2+) levels in the nanomolar range as well as micromolar-range Ca(2+) transients generated by cell stimulation. Here we present an integrated study combining the determination of the high-resolution crystal structure of a PMCA regulatory-domain/calmodulin complex with in vivo characterization and biochemical, biophysical and bioinformatics data that provide mechanistic insights into a two-step PMCA activation mechanism mediated by calcium-loaded calmodulin. The structure shows the entire PMCA regulatory domain and reveals an unexpected 2:1 stoichiometry with two calcium-loaded calmodulin molecules binding to different sites on a long helix. A multifaceted characterization of the role of both sites leads to a general structural model for calmodulin-mediated regulation of PMCAs that allows stringent, highly responsive control of intracellular calcium in eukaryotes, making it possible to maintain a stable, basal level at a threshold Ca(2+) concentration, where steep activation occurs.

Tidow, Henning; Poulsen, Lisbeth R

2012-01-01

344

Mechanisms controlling the distribution of two invasive Bromus species  

Directory of Open Access Journals (Sweden)

Full Text Available In order to predict future range shifts for invasive species it is important to explore their ability to acclimate to the new environment and understand physiological and reproductive constraints controlling their distribution. My dissertation studied mechanisms by which temperature may affect the distribution of two aggressive plant invaders in North America, Bromus tectorum and Bromus rubens. I first evaluated winter freezing tolerance of Bromus species and demonstrated that the mechanism explaining their distinct northern range limits is different acquisition time of freezing tolerance. While B. rubens has a slower rate of freezing acclimation that leads to intolerance of sudden, late-autumn drops in temperature below -12°C, B. tectorum rapidly hardens and so is not impacted by the sudden onset of severe late-autumn cold. In addition, the analysis of male reproductive development and seed production showed that neither species produces seed at or above 36°C, due to complete pollen sterility, which might trigger climate-mediated range contractions at B. tectorum and B. rubens southern margins. Finally, a detailed gas-exchange analysis combined with biochemical modelling demonstrated that both species acclimate to a broad range of temperatures and photosynthetic response to temperature does not explain their current range separation.

Olga Bykova

2014-03-01

345

Acute neuromuscular manifestations in a patient associated with ingesting octopus (Octopus sp.) / Manifestações neuromusculares agudas associadas à ingestão de polvo comum Octopus sp.  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Os autores relatam um quadro manifestado por sintomas neurológicos e musculares em uma mulher de 45 anos, que surgiu após o consumo da carne de polvo comum (Octopus sp.). A paciente apresentou intenso mal estar, parestesias em extremidades e área perioral, fraqueza muscular intensa e hipotensão arte [...] rial, seguidos de prurido importante e uma erupção eritêmato-descamativa disseminada tardia. Não foram observadas manifestações gastrintestinais ou febre, o que reduziu a probabilidade de uma intoxicação alimentar por conservação inadequada do molusco. A presença de sintomas neuro-musculares é sugestiva de ação de neurotoxinas, comprovadamente existentes em muitos gêneros de polvos e que podem ter sido ingeridas através do consumo das glândulas salivares ou acúmulo das toxinas na carne, por algum mecanismo ainda desconhecido. As toxinas dos polvos do gênero Octopus são pouco estudadas e julgamos esta comunicação importante por alertar para a possibilidade do envenenamento nos seres humanos que consomem carne de polvos e ainda sua diferenciação das intoxicações alimentares que ocorrem por conservação inadequada do animal. Abstract in english The authors report neuromuscular manifestations in a 45-year-old woman after consuming octopus meat (Octopus sp.). The patient presented malaise, paresthesias in perioral and extremity areas, intense muscular weakness and arterial hypotension, followed by severe itch and disseminated cutaneous rash. [...] Gastrointestinal manifestations and fever were not observed, reducing the probability of alimentary poisoning. The presence of muscular and neurological symptoms suggests neurotoxin action, which could have been ingested by the victim from the octopus salivary glands or from an accumulation of toxins in the meat, or by an unknown mechanism. There is little known about toxins of the Octopus genus and this communication is important alert to the possibility of poisoning in humans that eat octopus and its differentiation from alimentary poisonings arising from incorrect conservation of seafood.

Vidal, Haddad Junior; Regina, Moura.

2007-02-01

346

Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced by Electron Beam Freeform Fabrication  

Science.gov (United States)

The electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties demonstrated for electron beam deposited aluminum and titanium alloys are comparable to wrought products, although the microstructures of the deposits exhibit cast features. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. Tensile mechanical properties and microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains with interior dendritic structures, described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.

Domack, Marcia S.; Tainger, Karen M.

2006-01-01

347

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

DEFF Research Database (Denmark)

A theoretical analysis of an electromagnetic vibration controller is presented. The analyzed device consists of a pot-type iron core with a coil and a permanent magnet as a source of constant magnetic flux. The magnetic circuit is closed by a yoke, excited by an external harmonic mechanical force. The so generated magnetic flux variation induces alternating voltage in the electric circuit, which is dissipated in a shunt resistor. The induced current driven through the coil generates magnetic force, which damps the excitation force and changes the damped natural frequency of the oscillatory system. Due to the hysteretic effects in the magnetic material the internal losses influence the overall system’s performance. A mathematical model of the force balance in the oscillatory system is derived in a simplified, linearised form. The electric as well as mechanical system is modelled using lumped-parameter approach and the actuating principle for control of forced vibration is investigated.

Stein, George Juraj; Darula, Radoslav

2012-01-01

348

Investigation of the profile control mechanisms of dispersed particle gel.  

Science.gov (United States)

Dispersed particle gel (DPG) particles of nano- to micron- to mm-size have been prepared successfully and will be used for profile control treatment in mature oilfields. The profile control and enhanced oil recovery mechanisms of DPG particles have been investigated using core flow tests and visual simulation experiments. Core flow test results show that DPG particles can easily be injected into deep formations and can effectively plug the high permeability zones. The high profile improvement rate improves reservoir heterogeneity and diverts fluid into the low permeability zone. Both water and oil permeability were reduced when DPG particles were injected, but the disproportionate permeability reduction effect was significant. Water permeability decreases more than the oil permeability to ensure that oil flows in its own pathways and can easily be driven out. Visual simulation experiments demonstrate that DPG particles can pass directly or by deformation through porous media and enter deep formations. By retention, adsorption, trapping and bridging, DPG particles can effectively reduce the permeability of porous media in high permeability zones and divert fluid into a low permeability zone, thus improving formation profiles and enhancing oil recovery. PMID:24950174

Zhao, Guang; Dai, Caili; Zhao, Mingwei

2014-01-01

349

Cell shape, cytoskeletal mechanics, and cell cycle control in angiogenesis  

Science.gov (United States)

Capillary endothelial cells can be switched between growth and differentiation by altering cell-extracellular matrix interactions and thereby, modulating cell shape. Studies were carried out to determine when cell shape exerts its growth-regulatory influence during cell cycle progression and to explore the role of cytoskeletal structure and mechanics in this control mechanism. When G0-synchronized cells were cultured in basic fibroblast growth factor (FGF)-containing defined medium on dishes coated with increasing densities of fibronectin or a synthetic integrin ligand (RGD-containing peptide), cell spreading, nuclear extension, and DNA synthesis all increased in parallel. To determine the minimum time cells must be adherent and spread on extracellular matrix (ECM) to gain entry into S phase, cells were removed with trypsin or induced to retract using cytochalasin D at different times after plating. Both approaches revealed that cells must remain extended for approximately 12-15 h and hence, most of G1, in order to enter S phase. After this restriction point was passed, normally 'anchorage-dependent' endothelial cells turned on DNA synthesis even when round and in suspension. The importance of actin-containing microfilaments in shape-dependent growth control was confirmed by culturing cells in the presence of cytochalasin D (25-1000 ng ml-1): dose-dependent inhibition of cell spreading, nuclear extension, and DNA synthesis resulted. In contrast, induction of microtubule disassembly using nocodazole had little effect on cell or nuclear spreading and only partially inhibited DNA synthesis. Interestingly, combination of nocodazole with a suboptimal dose of cytochalasin D (100 ng ml-1) resulted in potent inhibition of both spreading and growth, suggesting that microtubules are redundant structural elements which can provide critical load-bearing functions when microfilaments are partially compromised. Similar synergism between nocodazole and cytochalasin D was observed when cytoskeletal stiffness was measured directly in living cells using magnetic twisting cytometry. These results emphasize the importance of matrix-dependent changes in cell and nuclear shape as well as higher order structural interactions between different cytoskeletal filament systems for control of capillary cell growth during angiogenesis.

Ingber, D. E.; Prusty, D.; Sun, Z.; Betensky, H.; Wang, N.

1995-01-01

350

Antimicrobial agents used in the control of periodontal biofilms: effective adjuncts to mechanical plaque control?  

Scientific Electronic Library Online (English)

Full Text Available The control of biofilm accumulation on teeth has been the cornerstone of periodontal disease prevention for decades. However, the widespread prevalence of gingivitis suggests the inefficiency of self-performed mechanical plaque control in preventing gingival inflammation. This is particularly releva [...] nt in light of recent evidence suggesting that long standing gingivitis increases the risk of loss of attachment and that prevention of gingival inflammation might reduce the prevalence of mild to moderate periodontitis. Several antimicrobials have been tested as adjuncts to mechanical plaque control in order to improve the results obtained with oral home care. Recent studies, including meta-analyses, have indicated that home care products containing chemical antimicrobials can provide gingivitis reduction beyond what can be accomplished with brushing and flossing. Particularly, formulations containing chlorhexidine, mouthrinses containing essential oils and triclosan/copolymer dentifrices have well documented clinical antiplaque and antigingivitis effects. In vivo microbiological tests have demonstrated the ability of these antimicrobial agents to penetrate the biofilm mass and to kill bacteria growing within biofilms. In addition, chemical antimicrobials can reach difficult-to-clean areas such as interproximal surfaces and can also impact the growth of biofilms on soft tissue. These agents have a positive track record of safety and their use does not seem to increase the levels of resistant species. Further, no study has been able to establish a correlation between mouthrinses containing alcohol and oral cancer. In summary, the adjunct use of chemical plaque control should be recommended to subjects with well documented difficulties in achieving proper biofilm control using only mechanical means.

Ricardo Palmier, Teles; Flavia Rocha Fonseca, Teles.

2009-06-01

351

Antimicrobial agents used in the control of periodontal biofilms: effective adjuncts to mechanical plaque control?  

Directory of Open Access Journals (Sweden)

Full Text Available The control of biofilm accumulation on teeth has been the cornerstone of periodontal disease prevention for decades. However, the widespread prevalence of gingivitis suggests the inefficiency of self-performed mechanical plaque control in preventing gingival inflammation. This is particularly relevant in light of recent evidence suggesting that long standing gingivitis increases the risk of loss of attachment and that prevention of gingival inflammation might reduce the prevalence of mild to moderate periodontitis. Several antimicrobials have been tested as adjuncts to mechanical plaque control in order to improve the results obtained with oral home care. Recent studies, including meta-analyses, have indicated that home care products containing chemical antimicrobials can provide gingivitis reduction beyond what can be accomplished with brushing and flossing. Particularly, formulations containing chlorhexidine, mouthrinses containing essential oils and triclosan/copolymer dentifrices have well documented clinical antiplaque and antigingivitis effects. In vivo microbiological tests have demonstrated the ability of these antimicrobial agents to penetrate the biofilm mass and to kill bacteria growing within biofilms. In addition, chemical antimicrobials can reach difficult-to-clean areas such as interproximal surfaces and can also impact the growth of biofilms on soft tissue. These agents have a positive track record of safety and their use does not seem to increase the levels of resistant species. Further, no study has been able to establish a correlation between mouthrinses containing alcohol and oral cancer. In summary, the adjunct use of chemical plaque control should be recommended to subjects with well documented difficulties in achieving proper biofilm control using only mechanical means.

Ricardo Palmier Teles

2009-06-01

352

Rheological controls on the terrestrial core formation mechanism  

Science.gov (United States)

Knowledge about the terrestrial core formation mechanism is still very limited. The fracturing mechanism was proposed for cold planetary interiors surrounded by an iron layer [Stevenson, 1981], which develops from an overlying magma ocean. In this case the cold central region is displaced by a degree one mode from the centre of the accreting planet and fractured due to the large stresses. In contrast the consideration of short-lived radioactive heating may result in warmer central regions and the preference of higher mode iron diapirism as core formation mechanism [e.g. Rubie et al., 2007; Ziethe and Spohn, 2007]. Until now most numerical models of core formation via diapirism were limited to the simulation of the sinking of a single diapir. We perform 2D cylindrical simulations using the code I2ELVIS applying the newly developed "spherical-Cartesian" methodology [Gerya and Yuen, 2007]. It combines finite differences on a fully staggered rectangular Eulerian grid and Lagrangian marker-in-cell technique for solving momentum, continuity and temperature equations as well as the Poisson equation for gravity potential in a self-gravitating planetary body. In the model the planet is surrounded by a low viscosity, massless fluid ("sticky air") to simulate a free surface [Schmeling et al., 2008]. We apply a temperature- and stress-dependent viscoplastic rheology inside Mars- and Earth-sized planets and include heat release due to radioactive decay, shear and adiabatic heating. As initial condition we use randomly distributed iron diapirs with random sizes in the range 50 to 100 km radius inside the accreting planet, which represent the iron delivered by predifferentiated impactors. A systematic investigation of the diapir behaviour for different activation volumes and Peierls stresses is being performed, and results are being compared to the isotopic time scale of core formation on terrestrial planets. We show that the rheology controls which formation mechanism becomes dominant. Depending on the maximum Peierls stress, which is strongly dependent on the water content of olivine [Katayama and Karato, 2008], we observe different regimes of core formation: A weak planet develops for low Peierls stress, where we observe diapir sinking, which is very similar to already published core formation models [e.g. Ziethe and Spohn, 2007]. However for high Peierls stress a strong planetary interior forms. Depending on the activation volume either an asymmetric iron layer forms, which surrounds the central part of the planet or a mixture of diapirism and fracturing mechanism develops. We find that the diapir sinking in this case may differ significantly from previous assumptions as we observe the formation of large temperature asymmetries and widespread rigid body rotation phenomena. They are controlled by spontaneously forming circular shear zones lubricated by shear heating. These phenomena favor a faster segregation of the iron and may have significant influence on geochemical signatures on dry accreted planetary bodies. They would allow for high temperature and pressure equilibration of the silicates with the metals without the need of a very deep global magma ocean.

Golabek, G. J.; Gerya, T. V.; Ziethe, R.; Kaus, B. J. P.; Tackley, P. J.

2009-04-01

353

The Control System Modeling and The Mechanical Structure Analysis For EMCVT  

OpenAIRE

The current automotive metallic belt continuously variable transmission (CVT) mostly use hydraulic system to push the cone disc and achieve the speed ratio control. A new Electrical Mechanical Continuously Variable Transmission without hydraulic control (Electrical Mechanical CVT, EMCVT) studied in this paper, uses the rolling screw mechanism to press cone disc, achieves speed regulation through the electronic control mechanism, and abandons the energy-intensive hydraulic system. In this pape...

Zhang, Lei; Cong, Xiaomei; Hujian Pan; Cai, Zuge; Yang, Xiumin

2013-01-01

354

Estimulação elétrica neuromuscular na disfunção patelofemoral: revisão de literatura Neuromuscular electric stimulation in patellofemoral dysfunction: riterature review  

Directory of Open Access Journals (Sweden)

Full Text Available A disfunção femoropatelar é uma deficiência bastante comum entre indivíduos jovens que acomete, principalmente, o sexo feminino e pode ser caracterizada por dor, edema e creptação retropatelar. Sistematizar o conhecimento em relação ao aumento da força muscular do quadríceps e alívio de dor em pacientes com disfunção femoropatelar, através da utilização da estimulação elétrica neuromuscular e exercícios resistidos. Trata se de um estudo de revisão narrativa da literatura no período de 2005 a 2011. Os critérios de inclusão foram artigos de intervenção, dos últimos seis anos, nos idiomas inglês, espanhol e português, que utilizaram o fortalecimento muscular e a eletroestimulação neuromuscular para reabilitação obtidos através de buscas nos bancos de dados eletrônicos Medline, Lilacs e na biblioteca Bireme. A busca bibliográfica resultou em 28 referências, destes foram excluídos nove de acordo com os objetivos e critérios de inclusão e foram selecionados 16 artigos para leitura dos resumos e posterior análise. A Estimulação Elétrica Neuromuscular (EENM de média frequência pode ser utilizada associada a exercícios resistidos como coadjuvante no tratamento da disfunção femoropatelar (DFP, tanto para se obter um reequilíbrio muscular quanto para o alívio da dor.Patellofemoral dysfunction is a fairly common deficiency among young individuals that primarily affects females and may be characterized by pain, swelling and retropatellar crepitation. The purpose of this review of literature from the period between 2005 and 2011 was to systematize knowledge in relation to the increase in quadriceps muscle strength and pain relief in patients with patellofemoral dysfunction, using neuromuscular electrical stimulation and resistance exercises. The inclusion criteria were intervention articles from the past six years, in English, Spanish and Portuguese, which used muscle strengthening and neuromuscular electrical stimulation for rehabilitation obtained through searches in the electronic databases Medline and Lilacs and in the Bireme library. The bibliographic search yielded 28 references, of which nine were excluded in accordance with the aims and inclusion criteria while 16 articles were selected for reading of the abstracts and subsequent analysis. Mediumfrequency Neuromuscular Electrical Stimulation (NMES can be used in association with resistance exercises as an adjuvant in the treatment of patellofemoral dysfunction (PFD, both to achieve muscle rebalance and for pain relief.

Ricardo Lucas dos Santos

2013-02-01

355

Estimulação elétrica neuromuscular na disfunção patelofemoral: revisão de literatura / Neuromuscular electric stimulation in patellofemoral dysfunction: riterature review  

Scientific Electronic Library Online (English)

Full Text Available A disfunção femoropatelar é uma deficiência bastante comum entre indivíduos jovens que acomete, principalmente, o sexo feminino e pode ser caracterizada por dor, edema e creptação retropatelar. Sistematizar o conhecimento em relação ao aumento da força muscular do quadríceps e alívio de dor em pacie [...] ntes com disfunção femoropatelar, através da utilização da estimulação elétrica neuromuscular e exercícios resistidos. Trata se de um estudo de revisão narrativa da literatura no período de 2005 a 2011. Os critérios de inclusão foram artigos de intervenção, dos últimos seis anos, nos idiomas inglês, espanhol e português, que utilizaram o fortalecimento muscular e a eletroestimulação neuromuscular para reabilitação obtidos através de buscas nos bancos de dados eletrônicos Medline, Lilacs e na biblioteca Bireme. A busca bibliográfica resultou em 28 referências, destes foram excluídos nove de acordo com os objetivos e critérios de inclusão e foram selecionados 16 artigos para leitura dos resumos e posterior análise. A Estimulação Elétrica Neuromuscular (EENM) de média frequência pode ser utilizada associada a exercícios resistidos como coadjuvante no tratamento da disfunção femoropatelar (DFP), tanto para se obter um reequilíbrio muscular quanto para o alívio da dor. Abstract in english Patellofemoral dysfunction is a fairly common deficiency among young individuals that primarily affects females and may be characterized by pain, swelling and retropatellar crepitation. The purpose of this review of literature from the period between 2005 and 2011 was to systematize knowledge in rel [...] ation to the increase in quadriceps muscle strength and pain relief in patients with patellofemoral dysfunction, using neuromuscular electrical stimulation and resistance exercises. The inclusion criteria were intervention articles from the past six years, in English, Spanish and Portuguese, which used muscle strengthening and neuromuscular electrical stimulation for rehabilitation obtained through searches in the electronic databases Medline and Lilacs and in the Bireme library. The bibliographic search yielded 28 references, of which nine were excluded in accordance with the aims and inclusion criteria while 16 articles were selected for reading of the abstracts and subsequent analysis. Mediumfrequency Neuromuscular Electrical Stimulation (NMES) can be used in association with resistance exercises as an adjuvant in the treatment of patellofemoral dysfunction (PFD), both to achieve muscle rebalance and for pain relief.

Ricardo Lucas dos, Santos; Márcia Leal São Pedro, Souza; Fernanda Andrade dos, Santos.

2013-02-01

356

Control rod driving mechanism, and control device and operation method therefor  

International Nuclear Information System (INIS)

The upper portion of a housing of control rod driving mechanisms is secured to a reactor pressure vessel, and the lower portion thereof is sealed by a closing plug. Gears are formed on the outer circumference of a driving shaft vertically moving with the linkage of a control rod in a pressure vessel, and a linear reluctance motor comprising a stator iron core having gears on the inner circumference of a stator and a stator coil for driving the driving shaft. There are disposed a latch mechanism for holding the control rod by engaging with the gears of the driving shaft and a position detector for detecting the position of the inserted control rod by the gears of the driving shaft or magnets mounted to the gears. Since the inner structure can be simplified with no shaft-sealing portion, the frequency for the maintenance and inspection can be reduced to improve the reliability of sealing portions of the pressure vessel. The space for maintenance and inspection of the lower portion of the pressure vessel can be reduced thereby making the height of a reactor building low and strengthen the earthquake proof structure. (N.H.)

357

A influência da fadiga neuromuscular e da acidose metabólica sobre a corrida de 400 metros / Influence of neuromuscular fatigue and metabolic acidosis on the 400-meter race  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Languages: English, Portuguese Abstract in portuguese Exercícios inabituais podem levar a danos musculares que persistem por alguns dias diminuindo a capacidade de desempenho em decorrência da fadiga. Além disso, o aumento da acidose intramuscular pode limitar o metabolismo celular no processo de gerar trabalho. Com isso, esta pesquisa teve como finali [...] dade analisar a influência da fadiga neuromuscular e da acidose metabólica sobre a corrida de 400 metros. Foram selecionados 20 indivíduos, sedentários, com idade entre 18 e 35 anos. Estes foram submetidos aos seguintes protocolos: teste incremental em esteira, para determinação do VO2max; limiares aeróbio e anaeróbio, teste de 400m (400/C), atividade pliométrica, com repouso ativo/passivo, seguida de corrida de 400m logo após (400/Pós) e 24 horas após a atividade pliométrica (400/24h). Os resultados obtidos mostram que, quando comparados os grupos ativo e passivo, não apresentaram diferenças significantes no desempenho dos 400/ Pós, mas o tempo deste foi maior, para os dois grupos quando comparado com os 400/C. No entanto, o 400/24h não foi significantemente diferente quando comparado com o 400/C para ambos os grupos. Concluise que, independente do tipo de recuperação - ativa ou passiva -, a diminuição de desempenho em uma corrida de 400 metros após atividade pliométrica parece ser ocasionada por mecanismos neuromusculares que levam à fadiga e não a limitações metabólicas. Abstract in english Unusual exercises can lead to muscle damage that persists for a few days reducing performance ability due to fatigue onset. Moreover, intramuscular acidity increase can limit the cell metabolism in the process of producing work. Therefore, the objective of this research was to analyze the influence [...] of neuromuscular fatigue and metabolic acidity in the 400 m race. The selected sample consisted of 20 sedentary individuals, aged between 18 and 35 years. They were submitted to the following protocols: treadmill incremental test for determination of VO2max; aerobic and anaerobic threshold; 400m race test (400/R); plyometric activity with active/passive rest followed by 400m race immediately after (400/Post) and 24 hours after the plyometric activity (400/24h). The obtained results show that when the active and passive groups are compared, they do not show significant difference in 400/Post performance, but this time was longer for both groups when compared with the 400/R. Nevertheless, the 400/24h was not significantly different when compared with the 400/R to both groups. It was concluded that regardless of the kind of recovery, active or passive, the performance reduction in a 400-meter race after plyometric activity seems to occur by neuromuscular mechanisms that lead to fatigue and not to metabolic limitations.

Flávio Roberto, Pelicer; Wonder Passoni, Higino; Ricardo Yoshio, Horita; Franco Carlos, Meira; Alexandre Policher, Alves.

2011-04-01

358

Hemodynamic and Lactic Acid Responses to Proprioceptive Neuromuscular Facilitation Exercise  

OpenAIRE

The hemodynamic and metabolic responses to proprioceptive neuromuscular facilitation (PNF) exercise were examined in 32 male university students (aged 19-28 years). Ten repetitions of PNF exercises were applied to the subjects’ dominant upper extremities in the following order: as an agonist pattern flexion, adduction and external rotation; and as an antagonist pattern extension, abduction and internal rotation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP),...

Zuhal Gültekin; Ayse Kin-Isler; Özgür Sürenkök

2006-01-01

359

Glutamate inhibitory action of matrine at the crayfish neuromuscular junction.  

OpenAIRE

The effect of some alkaloids from Sophora flavescens (matrine, oxymatrine and N-methylcytisine) on glutamate-induced responses was investigated using electrophysiological techniques at the crayfish neuromuscular junction. At concentrations greater than 0.1 mM, matrine depressed both glutamate-induced responses and neurally evoked excitatory junctional potentials. Oxymatrine was less powerful than matrine, and N-methylcytisine was not effective. Matrine also depressed quisqualate-induced respo...

Ishida, M.; Shinozaki, H.

1984-01-01

360

Neuromuscular development of Aeolidiella stephanieae Valdez, 2005 (Mollusca, Gastropoda, Nudibranchia)  

OpenAIRE

Background: Studies on the development of the nervous system and the musculature of invertebrates have become more sophisticated and numerous within the last decade and have proven to provide new insights into the evolutionary history of organisms. In order to provide new morphogenetic data on opisthobranch gastropods we investigated the neuromuscular development in the nudibranch Aeolidiella stephanieae Valdez, 2005 using immunocytochemistry as well as F-actin labelling in conjunction with c...

Kristof, Alen; Klussmann-kolb, Annette

2010-01-01

361

Current status on electrodiagnostic standards and guidelines in neuromuscular disorders.  

Science.gov (United States)

The aim of this review is to present the status of electrodiagnostic standards and guidelines in neuromuscular disorders. Electrodiagnostic guidelines are developed on the background of medical technology assessment, wherefore a short presentation of medical technology assessment is given covering: (1) Evidence-based medicine, i.e. "to do the right thing", describing practice parameters and the STARD initiative which introduces evidence-based medicine in electrodiagnostic medicine, (2) Continuous quality improvement, i.e. "to do the thing right", describing variation among laboratories in methods and interpretation of tests, and the need for medical audit and implementation of electrodiagnostic guidelines, (3) Outcome studies, i.e. "is it worthwhile to do the right thing right?". In electrodiagnostic medicine there are very few outcome studies. Standards and guidelines described in the literature for different neuromuscular disorders are presented, often as figures or tables. These cover guidelines developed in detail for CIDP by expert consensus multicentre groups by AAN, INCAT, EFNS/PNS and for other inflammatory demyelinating neuropathies are described, as well as guidelines differentiating between demyelinating pathophysiology and axonal loss by motor and sensory nerve conduction studies. Furthermore, electrodiagnostic guidelines for ALS as detailed in the El Escorial, the modified El Escorial and the recent supplementary Awaji criteria are described and presented in a comprehensive table. Only few electrodiagnostic guidelines are published for nerve entrapment, cervical radiculopathy and neuromuscular transmission failure whereas none are known for myopathy. If no electrodiagnostic criteria for a given disorder exist, criteria for the electrodiagnostic examination are described if present. It is concluded that future research is needed in order to develop more electrodiagnostic guidelines in neuromuscular disorders by international expert consensus groups. Such research should use an evidence-based medicine approach and medical technology assessment and include continuous quality development and outcome studies. PMID:20673740

Fuglsang-Frederiksen, Anders; Pugdahl, Kirsten

2011-03-01

362

Emerging considerations in the reversal of neuromuscular blockade and residual block  

OpenAIRE

Incomplete recovery following reversal of neuromuscular blockade can present as a clinical problem in surgical patients. Emerging pharmacologic solutions may prevent such adverse outcomes in the future. We briefly review two methods of pharmacologic reversal of neuromuscular blockade. Both methods of reversal are effective. However the early studies of the new compound, sugammadex has been shown to achieve a more rapid, stable reversal of steroidal based neuromuscular blocking agents compared...

Jankowski, Christopher J.; JURAJ SPRUNG; Nicholson, Wayne T.

2008-01-01

363

Fatigue in neuromuscular disorders: Focus on Guillain-Barré syndrome and Pompe disease  

OpenAIRE

Fatigue accounts for an important part of the burden experienced by patients with neuromuscular disorders. Substantial high prevalence rates of fatigue are reported in a wide range of neuromuscular disorders, such as Guillain–Barré syndrome and Pompe disease. Fatigue can be subdivided into experienced fatigue and physiological fatigue. Physiological fatigue in turn can be of central or peripheral origin. Peripheral fatigue is an important contributor to fatigue in neuromuscular disorders, ...

Vries, J. M.; Hagemans, M. L. C.; Bussmann, J. B. J.; Ploeg, A. T.; Doorn, P. A.

2010-01-01

364

Neutralization of the neuromuscular activity of bothropstoxin-i, a myotoxin from Bothrops jararacussu snake venom, by a hydroalcoholic extract of Casearia sylvestris Sw. (guaçatonga  

Directory of Open Access Journals (Sweden)

Full Text Available Numerous plants are used as snakebite antidotes in Brazilian folk medicine, including Casearia sylvestris Swartz, popularly known as guaçatonga. In this study, we examined the action of a hydroalcoholic extract from C. sylvestris on the neuromuscular blockade caused by bothropstoxin-I (BthTX-I, a myotoxin from Bothrops jararacussu venom, in mouse isolated phrenic nerve-diaphragm (PND preparations. Aqueous (8 and 12 mg/ml, n=4 and 5, respectively and hydroalcoholic (12 mg/ml, n=12 extracts of the leaves of C. sylvestris caused facilitation in PND preparations followed by partial neuromuscular blockade. BthTX-I (20 µg/ml, n=4 caused 50% paralysis after 65±15 min (mean ± S.E.M. Preincubation (30 min at 37° C of BthTX-I (20 µg/ml, n=4 with a concentration of the hydroalcoholic extract (4 mg/ml that had no neuromuscular activity, such as the control (n=5, prevented the neuromuscular blockade caused by the toxin. This protection may be mediated by compounds such as flavonoids and phenols identified by thin-layer chromatography and colorimetric assays.

Y. Oshima-Franco

2005-12-01

365

A temporary decrease in twitch response following reversal of rocuronium-induced neuromuscular block with a small dose of sugammadex in a pediatric patient.  

Science.gov (United States)

We report a temporary decrease in twitch response following reversal of rocuronium-induced neuromuscular block with a small dose of sugammadex in our dose-finding study in pediatric patients. A 19-month-old female infant (9.6 kg, 80 cm) was scheduled for elective cheiloplasty surgery. Anesthesia was induced with nitrous oxide 50% and sevoflurane 5% and maintained with air, oxygen, sevoflurane 3%, and fentanyl (total, 3 ?g/kg). Neuromuscular monitoring was performed at the adductor pollicis muscle after induction of anesthesia but before the administration of rocuronium. Total dose of rocuronium during the surgery was 0.9 mg/kg. Neuromuscular block was reversed with 0.5 mg/kg sugammadex when one response was observed with post-tetanic count stimulation. Twitch responses after sugammadex administration showed a temporary decrease after its initial recovery. Maximum decreases in twitch responses were observed 17 min after initial dose of sugammadex. Twitch responses recovered to their control values after additional doses of 3.5 mg/kg sugammadex (4 mg/kg in total). Time from sugammadex administration to maximum decreases in twitch responses is earlier than has been reported in adults (20-70 min). It is demonstrated that following neuromuscular block reversal with insufficient dose of sugammadex, there is a possibility of the recurrence of residual paralysis within less than 20 min in pediatric patients. PMID:23963464

Iwasaki, Hajime; Takahoko, Kenichi; Otomo, Shigeaki; Sasakawa, Tomoki; Kunisawa, Takayuki; Iwasaki, Hiroshi

2014-04-01

366

Neuromuscular blocking action of the Theraphosa blondii spider venom  

Directory of Open Access Journals (Sweden)

Full Text Available In 1919, Houssay and Negrete reported that venoms of Theraphosidae spiders induced neuromuscular blockade. In 1993, a purified toxin from Grammostola spider venom was found to block the P-type voltage-dependent calcium channel (VDCC, causing neuromuscular blockade. We studied the mode of action of Theraphosa blondii venom, a large Theraphosidae spider from Northern Brazil, Venezuela, and The Guyanas in mouse phrenic nerve-diaphragm preparation. This venom elicited a partially reversible neuromuscular blockade and did not depress directly evoked twitches or alter the membrane potential. Neostigmine produced only a poor antagonistic effect on partially blocked diaphragms. However, completely blocked miniature endplate potentials (m.e.p.ps were reverted by neostigmine. These results can be explained by the presence of toxins in the venom that interact with the endplate receptor at the acetylcholine sites (curaremimetic toxins and toxins that inhibit the P-type voltage-dependent calcium channel (VDCC (omega -toxins. This study shows that Theraphosidae venoms, especially those of the Theraphosa blondii, are a source of curaremimetic toxins and omega -toxins of possible interest as tools in bioscientific research.

M. D. Fontana

2002-01-01

367

Neuromuscular activity of Bothrops fonsecai snake venom in vertebrate preparations.  

Science.gov (United States)

The neuromuscular activity of venom from Bothrops fonsecai, a lancehead endemic to southeastern Brazil, was investigated. Chick biventer cervicis (CBC) and mouse phrenic nerve-diaphragm (PND) preparations were used for myographic recordings and mouse diaphragm muscle was used for membrane resting potential (RP) and miniature end-plate potential (MEPP) recordings. Creatine kinase release and muscle damage were also assessed. In CBC, venom (40, 80 and 160?g/ml) produced concentration- and time-dependent neuromuscular blockade (50% blockade in 85±9 min and 73±8 min with 80 and 160?g/ml, respectively) and attenuated the contractures to 110?M ACh (78-100% inhibition) and 40mM KCl (45-90% inhibition). The venom-induced decrease in twitch-tension in curarized, directly-stimulated preparations was similar to that in indirectly stimulated preparations. Venom (100 and 200?g/ml) also caused blockade in PND preparations (50% blockade in 94±13 min and 49±8 min with 100 and 200?g/ml, respectively) but did not alter the RP or MEPP amplitude. In CBC, venom caused creatine kinase release and myonecrosis. The venom-induced decrease in twitch-tension and in the contractures to ACh and K(+) were abolished by preincubating venom with commercial antivenom. These findings indicate that Bothrops fonsecai venom interferes with neuromuscular transmission essentially through postsynaptic muscle damage that affects responses to ACh and KCl. These actions are effectively prevented by commercial antivenom. PMID:25028603

Fernandes, Carla T; Giaretta, Vânia Ma; Prudêncio, Luiz S; Toledo, Edvana O; da Silva, Igor Rf; Collaço, Rita Co; Barbosa, Ana M; Hyslop, Stephen; Rodrigues-Simioni, Léa; Cogo, José C

2014-01-01

368

Fatty replacement of lower paraspinal muscles: normal and neuromuscular disorders  

Energy Technology Data Exchange (ETDEWEB)

The physiologic replacement of the lower paraspinal muscles by fat was evaluated in 157 patients undergoing computed tomography for reasons unrelated to abnormalities of the locomotor system. Five patients with neuromuscular disorders were similarly evaluated. The changes were graded according to severity at three spinal levels: lower thoracic-upper lumbar, midlumbar, and lumbosacral. The results were analyzed in relation to age and gender. It was found that fatty replacement of paraspinal muscles is a normal age-progressive phenomenon most prominent in females. It progresses down the spine, being most advanced in the lumbosacral region. The severest changes in the five patients with neuromuscular disorders (three with poliomyelitis and two with progressive muscular dystrophy) consisted of complete muscle group replacement by fat. In postpoliomyelitis atrophy, the distribution was typically asymmetric and sometimes lacked clinical correlation. In muscular dystrophy, fatty replacement was symmetric, showing relative sparing of the psoas and multifidus muscles. In patients with neuromuscular diseases, computed tomography of muscles may be helpful in planning a better rehabilitation regimen.

Hader, H.; Gadoth, N.; Heifetz, H.

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