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Sample records for surface electromyography activity

  1. Surface electromyography activity of trunk muscles during wheelchair propulsion.

    Science.gov (United States)

    Yang, Yu-Sheng; Koontz, Alicia M; Triolo, Ronald J; Mercer, Jennifer L; Boninger, Michael L

    2006-12-01

    Trunk instability due to paralysis can have adverse effects on posture and function in a wheelchair. The purpose of this study was to record trunk muscle recruitment patterns using surface electromyography from unimpaired individuals during wheelchair propulsion under various propulsion speed conditions to be able to design trunk muscle stimulation patterns for actual wheelchair users with spinal cord injury. Fourteen unimpaired subjects propelled a test wheelchair on a dynamometer system at two steady state speeds of 0.9 m/s and 1.8 m/s and acceleration from rest to their maximum speed. Lower back/abdominal surface electromyography and upper body movements were recorded for each trial. Based on the hand movement during propulsion, the propulsive cycle was further divided into five stages to describe the activation patterns. Both abdominal and back muscle groups revealed significantly higher activation at early push and pre-push stages when compared to the other three stages of the propulsion phase. With increasing propulsive speed, trunk muscles showed increased activation (Pactivity was significantly higher than abdominal muscle activity across the three speed conditions (PAbdominal and back muscle groups cocontracted at late recovery phase and early push phase to provide sufficient trunk stability to meet the demands of propulsion. This study provides an indication of the amount and duration of stimulation needed for a future application of electrical stimulation of the trunk musculature for persons with spinal cord injury.

  2. Impact of functional appliances on muscle activity: a surface electromyography study in children.

    Science.gov (United States)

    Woźniak, Krzysztof; Piątkowska, Dagmara; Szyszka-Sommerfeld, Liliana; Buczkowska-Radlińska, Jadwiga

    2015-01-20

    Electromyography (EMG) is the most objective tool for assessing changes in the electrical activity of the masticatory muscles. The purpose of the study was to evaluate the tone of the masseter and anterior temporalis muscles in growing children before and after 6 months of treatment with functional removable orthodontic appliances. The sample conisted of 51 patients with a mean age 10.7 years with Class II malocclusion. EMG recordings were performed by using a DAB-Bluetooth instrument (Zebris Medical GmbH, Germany). Recordings were performed in mandibular rest position, during maximum voluntary contraction (MVC), and during maximum effort. The results of the study indicated that the electrical activity of the muscles in each of the clinical situations was the same in the group of girls and boys. The factor that determined the activity of the muscles was their type. In mandibular rest position and in MVC, the activity of the temporalis muscles was significantly higher that that of the masseter muscels. The maximum effort test indicated a higher fatigue in masseter than in temporalis muscles. Surface electromyography is a useful tool for monitoring muscle activity. A 6-month period of functional therapy resulted in changes in the activity of the masticatory muscles.

  3. [Measurement of muscular activity by surface electromyography during use of an emergency evacuation chair].

    Science.gov (United States)

    Caballero Martín, Elena; Gallego Fernández, Yolanda; Molina, Josep María

    2012-01-01

    To compare the different techniques used by paramedics in handling an emergency evacuation chair and to identify themore ergonomically favourable technique, based on an analysis ofmuscular activity using surface electromyography. The trial was based on descending stairs, through four possible arrangements for the same transport operation, where the study variables were: worker anthropometrics (5th and 95th percentiles, corresponding to the extremes of the normal height-weight distribution curve), worker location during chair transport (upper or lower end of the chair), and the position of the individual at the lower end (facing front or backwards during descent). For both workers participating in the study, the more favourable working position during chair descent was at the lower end of the chairwhile facing forward, as this was associated with less muscular activity. In general, physical demands on the various muscles studied was greater for the worker corresponding to the 5th percentile (i.e., lower height-weight), except for the paravertebral musculature which, for certain maneuvers involving manipulation was significantly greater than the 95th percentile. When descending stairs while transporting an emergency evacuation chair, the position involving least muscular activity is located at the lower end of the chair, and descending while facing forwards. Copyright belongs to the Societat Catalana de Seguretat i Medicina del Treball.

  4. The study of surface electromyography used for the assessment of abductor hallucis muscle activity in patients with hallux valgus.

    Science.gov (United States)

    Mortka, Kamila; Lisiński, Przemysław; Wiertel-Krawczuk, Agnieszka

    2018-01-26

    Hallux valgus is a common foot disorder. In patients with hallux valgus, the anatomy and biomechanics of foot is subject to alterations. The aim of this clinical and neurophysiological study is to compare the activity of abductor hallucis (AbdH) muscle between the group of patients with hallux valgus and control group of healthy people, with the use of surface electromyography. The study involved 44 feet with diagnosed hallux valgus (research group) and 42 feet without deformation (control group). The X-ray images, measurements of range of motion in the first metatarsophalangeal joint and in hallux interphalangeal joint, and the surface electromyography study recorded from AbdH muscle were performed. Considering the amplitude of motor unit action potential, study participants with hallux valgus demonstrate significantly less activity of AbdH muscle than people without hallux valgus deformity. This activity is not dependent on the severity of valgus, age, or range of motion. It is speculated that the changes of the AbdH function may occur in the period before clinical appearance of hallux valgus deformity, or at the onset of distortion development. Further studies are needed for a comprehensive assessment of AbdH muscle in patients with hallux valgus.

  5. Use of surface electromyography in phonation studies: an integrative review

    Science.gov (United States)

    Balata, Patricia Maria Mendes; Silva, Hilton Justino da; Moraes, Kyvia Juliana Rocha de; Pernambuco, Leandro de Araújo; Moraes, Sílvia Regina Arruda de

    2013-01-01

    Summary Introduction: Surface electromyography has been used to assess the extrinsic laryngeal muscles during chewing and swallowing, but there have been few studies assessing these muscles during phonation. Objective: To investigate the current state of knowledge regarding the use of surface electromyography for evaluation of the electrical activity of the extrinsic muscles of the larynx during phonation by means of an integrative review. Method: We searched for articles and other papers in the PubMed, Medline/Bireme, and Scielo databases that were published between 1980 and 2012, by using the following descriptors: surface electromyography and voice, surface electromyography and phonation, and surface electromyography and dysphonia. The articles were selectedon the basis ofinclusion and exclusion criteria. Data Synthesis: This was carried out with a cross critical matrix. We selected 27 papers,i.e., 24 articles and 3 theses. The studies differed methodologically with regards to sample size and investigation techniques, making it difficult to compare them, but showed differences in electrical activity between the studied groups (dysphonicsubjects, non-dysphonicsubjects, singers, and others). Conclusion: Electromyography has clinical applicability when technical precautions with respect to application and analysis are obeyed. However, it is necessary to adopt a universal system of assessment tasks and related measurement techniques to allow comparisons between studies. PMID:25992030

  6. Relationship between lower limb position and pelvic floor muscle surface electromyography activity in menopausal women: a prospective observational study

    Directory of Open Access Journals (Sweden)

    Halski T

    2017-01-01

    Full Text Available Tomasz Halski,1 Kuba Ptaszkowski,2 Lucyna Słupska,1 Robert Dymarek,3 Małgorzata Paprocka-Borowicz2 1Department of Physiotherapy, Opole Medical School, Opole, 2Department of Clinical Biomechanics and Physiotherapy in Motor System Disorders, 3Department of Nervous System Diseases, Faculty of Health Science, Wroclaw Medical University, Wroclaw, Poland Objectives: In physiotherapeutic practice, special attention is being given to the reciprocal anatomical, physiological, and biomechanical relationship of the pelvis and the structures connected to it. However, the scientific literature shows mainly the theoretical information about their mutual connections. The lack of information about these relations from a practical aspect coupled with the paucity of scientific papers on the impact of posture changes on the pelvic floor led the authors to conduct this study. The primary aim of this study was to compare the resting and functional bioelectrical activities of pelvic floor muscles (PFMs depending on three different positions of the lower limbs (positions A, B, and C in the supine position.Materials and methods: This was a prospective observational study evaluating resting and functional activities of the PFM depending on the position of the lower limbs. The study was carried out at the Department and Clinic of Urology, University Hospital in Wroclaw, Poland and the target group were women in the menopausal period. Bioelectrical activity of PFM was recorded using a surface electromyographic instrument in the supine position. Results of the values obtained in A, B, and C positions were compared using a one-way analysis of variance.Results: In position A, the average resting surface electromyography (sEMG activity of PFM was 6.9±2.6 µV; in position B, the result was 6.9±2.5 µV and in position C, the resting sEMG activity was 5.7±1.8 µV (P=0.0102. The results of the functional bioelectrical activity of PFM were as follows: position A – 20.3

  7. Muscular Activities Measurements of Forward Lean and Upright Sitting Motorcycling Postures via Surface Electromyography (sEMG

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    Ma’arof Muhammad Izzat Nor

    2017-01-01

    Full Text Available Motorcycling postures are generically speculated to be physical and physiologically demanding – which in-turn may lead to motorcycling fatigue, and then becoming a possible factor to road accident. The objective of this study was to measure the muscular activities of various motorcycling postures. High muscular activity reading will signifies that motorcycling is indeed physically and physiologically demanding to the motorcyclist. For this particular study, the following postures were tested: i forward lean, ii upright sitting, and iii neutral sitting (as control. Surface electromyography (sEMG measurement was conducted on the following muscles: i extensor carpi radialis, ii upper trapezius iii latissimus dorsi, and iv erector spinae. The results showed that for all test subjects, the muscular activities readings for the forward lean posture was actually close to neutral sitting’s. Whilst, the upright sitting had showed much higher muscular activities measurement instead. Conclusively, this study had proven that any types of discomforts associated with the forward lean posture is not originated from muscular activities. Whereas, confirming that any discomforts in regards to the upright sitting is indeed related to muscular activities. Further studies are warranted to discover the actual risk factors that causes physical and physiological discomforts for the forward lean motorcycling posture.

  8. Extracting Extensor Digitorum Communis Activation Patterns using High-Density Surface Electromyography

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    Xiaogang eHu

    2015-10-01

    Full Text Available The extensor digitorum communis muscle plays an important role in hand dexterity during object manipulations. This multi-tendinous muscle is believed to be controlled through separate motoneuron pools, thereby forming different compartments that control individual digits. However, due to the complex anatomical variations across individuals and the flexibility of neural control strategies, the spatial activation patterns of the extensor digitorum communis compartments during individual finger extension have not been fully tracked under different task conditions.The objective of this study was to quantify the global spatial activation patterns of the extensor digitorum communis using high-density (7×9 surface electromyogram (EMG recordings. The muscle activation map (based on the root mean square of the EMG was constructed when subjects performed individual four finger extensions at the metacarpophalangeal joint, at different effort levels and under different finger constraints (static and dynamic. Our results revealed distinct activation patterns during individual finger extensions, especially between index and middle finger extensions, although the activation between ring and little finger extensions showed strong covariance. The activation map was relatively consistent at different muscle contraction levels and for different finger constraint conditions. We also found that distinct activation patterns were more discernible in the proximal-distal direction than in the radial-ulnar direction. The global spatial activation map utilizing surface grid EMG of the extensor digitorum communis muscle provides information for localizing individual compartments of the extensor muscle during finger extensions. This is of potential value for identifying more selective control input for assistive devices. Such information can also provide a basis for understanding hand impairment in individuals with neural disorders.

  9. Surface electromyography can quantify temporal and spatial patterns of activation of intrinsic human foot muscles.

    Science.gov (United States)

    Ferrari, E; Cooper, G; Reeves, N D; Hodson-Tole, E F

    2018-04-01

    Intrinsic foot muscles (IFM) are a crucial component within the human foot. Investigating their functioning can help understand healthy and pathological behaviour of foot and ankle, fundamental for everyday activities. Recording muscle activation from IFM has been attempted with invasive techniques, mainly investigating single muscles. Here we present a novel methodology, to investigate the feasibility of recording physiological surface EMG (sEMG) non-invasively and quantify patterns of activation across the whole plantar region of the foot. sEMG were recorded with a 13 × 5 array from the sole of the foot (n = 25) during two-foot stance, two-foot tiptoe and anterior/posterior sways. Physiological features of sEMG were analysed. During anterior/posterior epochs within the sway task, sEMG patterns were analysed in terms of signal amplitude (intensity) and structure (Sample Entropy) distribution, by evaluating the centre of gravity (CoG) of each topographical map. Results suggest signals are physiological and not affected by loading. Both amplitude and sample entropy CoG coordinates were grouped in one region and overlapped, suggesting that the region with highest amplitude corresponds with the most predictable signal. Therefore, both spatial and temporal features of IFM activation may be recorded non-invasively, providing opportunity for more detailed investigation of IFM function in healthy and patient populations. Copyright © 2018. Published by Elsevier Ltd.

  10. Surface electromyography physiology, engineering and applications

    CERN Document Server

    Farina, Dario

    2016-01-01

    The book presents a quantitative approach to the study and use of noninvasively detected electromyographic (EMG) signals, as well as their numerous applications in various aspects of the life sciences. Surface Electromyography: Physiology, Engineering, and Applications is an update of Electromyography: Physiology, Engineering, and Noninvasive Applications (Wiley-IEEE Press, 2004) and focuses on the developments that have taken place over the last decade. The first nine chapters deal with the generation, detection, understanding, interpretation, and modeling of EMG signals. Detection technology, with particular focus on EMG imaging techniques that are based on two-dimensional electrode arrays are also included in the first half of the book. The latter 11 chapters deal with applications, which range fro monitoring muscle fatigue, electrically elicited contractions, posture analysis, prevention of work-related and child-delivery-related neuromuscular disorders, ergonomics, movement analysis, physical therapy, ex...

  11. Robust Features Of Surface Electromyography Signal

    International Nuclear Information System (INIS)

    Sabri, M I; Miskon, M F; Yaacob, M R

    2013-01-01

    Nowadays, application of robotics in human life has been explored widely. Robotics exoskeleton system are one of drastically areas in recent robotic research that shows mimic impact in human life. These system have been developed significantly to be used for human power augmentation, robotics rehabilitation, human power assist, and haptic interaction in virtual reality. This paper focus on solving challenges in problem using neural signals and extracting human intent. Commonly, surface electromyography signal (sEMG) are used in order to control human intent for application exoskeleton robot. But the problem lies on difficulty of pattern recognition of the sEMG features due to high noises which are electrode and cable motion artifact, electrode noise, dermic noise, alternating current power line interface, and other noise came from electronic instrument. The main objective in this paper is to study the best features of electromyography in term of time domain (statistical analysis) and frequency domain (Fast Fourier Transform).The secondary objectives is to map the relationship between torque and best features of muscle unit activation potential (MaxPS and RMS) of biceps brachii. This project scope use primary data of 2 male sample subject which using same dominant hand (right handed), age between 20–27 years old, muscle diameter 32cm to 35cm and using single channel muscle (biceps brachii muscle). The experiment conduct 2 times repeated task of contraction and relaxation of biceps brachii when lifting different load from no load to 3kg with ascending 1kg The result shows that Fast Fourier Transform maximum power spectrum (MaxPS) has less error than mean value of reading compare to root mean square (RMS) value. Thus, Fast Fourier Transform maximum power spectrum (MaxPS) show the linear relationship against torque experience by elbow joint to lift different load. As the conclusion, the best features is MaxPS because it has the lowest error than other features and

  12. Robust Features Of Surface Electromyography Signal

    Science.gov (United States)

    Sabri, M. I.; Miskon, M. F.; Yaacob, M. R.

    2013-12-01

    Nowadays, application of robotics in human life has been explored widely. Robotics exoskeleton system are one of drastically areas in recent robotic research that shows mimic impact in human life. These system have been developed significantly to be used for human power augmentation, robotics rehabilitation, human power assist, and haptic interaction in virtual reality. This paper focus on solving challenges in problem using neural signals and extracting human intent. Commonly, surface electromyography signal (sEMG) are used in order to control human intent for application exoskeleton robot. But the problem lies on difficulty of pattern recognition of the sEMG features due to high noises which are electrode and cable motion artifact, electrode noise, dermic noise, alternating current power line interface, and other noise came from electronic instrument. The main objective in this paper is to study the best features of electromyography in term of time domain (statistical analysis) and frequency domain (Fast Fourier Transform).The secondary objectives is to map the relationship between torque and best features of muscle unit activation potential (MaxPS and RMS) of biceps brachii. This project scope use primary data of 2 male sample subject which using same dominant hand (right handed), age between 20-27 years old, muscle diameter 32cm to 35cm and using single channel muscle (biceps brachii muscle). The experiment conduct 2 times repeated task of contraction and relaxation of biceps brachii when lifting different load from no load to 3kg with ascending 1kg The result shows that Fast Fourier Transform maximum power spectrum (MaxPS) has less error than mean value of reading compare to root mean square (RMS) value. Thus, Fast Fourier Transform maximum power spectrum (MaxPS) show the linear relationship against torque experience by elbow joint to lift different load. As the conclusion, the best features is MaxPS because it has the lowest error than other features and show

  13. Relationship between lower limb position and pelvic floor muscle surface electromyography activity in menopausal women: a prospective observational study

    Science.gov (United States)

    Halski, Tomasz; Ptaszkowski, Kuba; Słupska, Lucyna; Dymarek, Robert; Paprocka-Borowicz, Małgorzata

    2017-01-01

    Objectives In physiotherapeutic practice, special attention is being given to the reciprocal anatomical, physiological, and biomechanical relationship of the pelvis and the structures connected to it. However, the scientific literature shows mainly the theoretical information about their mutual connections. The lack of information about these relations from a practical aspect coupled with the paucity of scientific papers on the impact of posture changes on the pelvic floor led the authors to conduct this study. The primary aim of this study was to compare the resting and functional bioelectrical activities of pelvic floor muscles (PFMs) depending on three different positions of the lower limbs (positions A, B, and C) in the supine position. Materials and methods This was a prospective observational study evaluating resting and functional activities of the PFM depending on the position of the lower limbs. The study was carried out at the Department and Clinic of Urology, University Hospital in Wroclaw, Poland and the target group were women in the menopausal period. Bioelectrical activity of PFM was recorded using a surface electromyographic instrument in the supine position. Results of the values obtained in A, B, and C positions were compared using a one-way analysis of variance. Results In position A, the average resting surface electromyography (sEMG) activity of PFM was 6.9±2.6 µV; in position B, the result was 6.9±2.5 µV and in position C, the resting sEMG activity was 5.7±1.8 µV (P=0.0102). The results of the functional bioelectrical activity of PFM were as follows: position A – 20.3±11.8 µV, position B – 19.9±10.6 µV, and position C – 25.3±10.9 µV (P=0.0104). Conclusion The results showed that in the supine position, the PFM achieved the lowest resting activity and the highest functional activity. Therefore, the supine position can be recommended for the diagnosis and therapy of weakened PFM. PMID:28115836

  14. A MATLAB-based graphical user interface for the identification of muscular activations from surface electromyography signals.

    Science.gov (United States)

    Mengarelli, Alessandro; Cardarelli, Stefano; Verdini, Federica; Burattini, Laura; Fioretti, Sandro; Di Nardo, Francesco

    2016-08-01

    In this paper a graphical user interface (GUI) built in MATLAB® environment is presented. This interactive tool has been developed for the analysis of superficial electromyography (sEMG) signals and in particular for the assessment of the muscle activation time intervals. After the signal import, the tool performs a first analysis in a totally user independent way, providing a reliable computation of the muscular activation sequences. Furthermore, the user has the opportunity to modify each parameter of the on/off identification algorithm implemented in the presented tool. The presence of an user-friendly GUI allows the immediate evaluation of the effects that the modification of every single parameter has on the activation intervals recognition, through the real-time updating and visualization of the muscular activation/deactivation sequences. The possibility to accept the initial signal analysis or to modify the on/off identification with respect to each considered signal, with a real-time visual feedback, makes this GUI-based tool a valuable instrument in clinical, research applications and also in an educational perspective.

  15. Quantitative analysis of surface electromyography during epileptic and nonepileptic convulsive seizures

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Conradsen, Isa; Moldovan, Mihai

    2014-01-01

    Objective: To investigate the characteristics of sustained muscle activation during convulsive epileptic and psychogenic nonepileptic seizures (PNES), as compared to voluntary muscle activation. The main goal was to find surface electromyography (EMG) features that can distinguish between convuls...

  16. Reliability of surface electromyography activity of gluteal and hamstring muscles during sub-maximal and maximal voluntary isometric contractions.

    Science.gov (United States)

    Bussey, Melanie D; Aldabe, Daniela; Adhia, Divya; Mani, Ramakrishnan

    2018-04-01

    Normalizing to a reference signal is essential when analysing and comparing electromyography signals across or within individuals. However, studies have shown that MVC testing may not be as reliable in persons with acute and chronic pain. The purpose of this study was to compare the test-retest reliability of the muscle activity in the biceps femoris and gluteus maximus between a novel sub-MVC and standard MVC protocols. This study utilized a single individual repeated measures design with 12 participants performing multiple trials of both the sub-MVC and MVC tasks on two separate days. The participant position in the prone leg raise task was standardised with an ultrasonic sensor to improve task precession between trials/days. Day-to-day and trial-to-trial reliability of the maximal muscle activity was examined using ICC and SEM. Day-to-day and trial-to-trial reliability of the EMG activity in the BF and GM were high (0.70-0.89) to very high (≥0.90) for both test procedures. %SEM was <5-10% for both tests on a given day but higher in the day-to-day comparisons. The lower amplitude of the sub-MVC is a likely contributor to increased %SEM (8-13%) in the day-to-day comparison. The findings show that the sub-MVC modified prone double leg raise results in GM and BF EMG measures similar in reliability and precision to the standard MVC tasks. Therefore, the modified prone double leg raise may be a useful substitute for traditional MVC testing for normalizing EMG signals of the BF and GM. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. A more precise, repeatable and diagnostic alternative to surface electromyography

    DEFF Research Database (Denmark)

    Harrison, Adrian P

    2018-01-01

    Acoustic myography (AMG) enables a detailed and accurate measurement of those muscles involved in a particular movement and is independent of electrical signals between the nerve and muscle, measuring solely muscle contractions, unlike surface electromyography (sEMG). With modern amplifiers...... and digital sound recording systems, measurements during physical activity both inside and outside a laboratory setting are now possible and accurate. Muscle sound gives a representation of the work of each muscle group during a complex movement, and under certain forms of movement even reveals both...

  18. SURFACE ELECTROMYOGRAPHY IN BIOMECHANICS: APPLICATIONS AND SIGNAL ANALYSIS ASPECTS

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    DEAK GRAłIELA-FLAVIA

    2009-12-01

    Full Text Available Surface electromyography (SEMG is a technique for detecting and recording the electrical activity of the muscles using surface electrodes. The EMG signal is used in biomechanics mainly as an indicator of the initiation of muscle activation, as an indicator of the force produced by a contracting muscle, and as an index ofthe fatigue occurring within a muscle. EMG, used as a method of investigation, can tell us if the muscle is active or not, if the muscle is more or less active, when it is on or off, how much active is it, and finally, if it fatigues.The purpose of this article is to discuss some specific EMG signal analysis aspects with emphasis on comparison type analysis and frequency fatigue analysis.

  19. Surface Electromyography Signal Processing and Classification Techniques

    Science.gov (United States)

    Chowdhury, Rubana H.; Reaz, Mamun B. I.; Ali, Mohd Alauddin Bin Mohd; Bakar, Ashrif A. A.; Chellappan, Kalaivani; Chang, Tae. G.

    2013-01-01

    Electromyography (EMG) signals are becoming increasingly important in many applications, including clinical/biomedical, prosthesis or rehabilitation devices, human machine interactions, and more. However, noisy EMG signals are the major hurdles to be overcome in order to achieve improved performance in the above applications. Detection, processing and classification analysis in electromyography (EMG) is very desirable because it allows a more standardized and precise evaluation of the neurophysiological, rehabitational and assistive technological findings. This paper reviews two prominent areas; first: the pre-processing method for eliminating possible artifacts via appropriate preparation at the time of recording EMG signals, and second: a brief explanation of the different methods for processing and classifying EMG signals. This study then compares the numerous methods of analyzing EMG signals, in terms of their performance. The crux of this paper is to review the most recent developments and research studies related to the issues mentioned above. PMID:24048337

  20. Comparison of Muscle Onset Activation Sequences between a Golf or Tennis Swing and Common Training Exercises Using Surface Electromyography: A Pilot Study

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    John M. Vasudevan

    2016-01-01

    Full Text Available Aim. The purpose of this pilot study is to use surface electromyography to determine an individual athlete’s typical muscle onset activation sequence when performing a golf or tennis forward swing and to use the method to assess to what degree the sequence is reproduced with common conditioning exercises and a machine designed for this purpose. Methods. Data for 18 healthy male subjects were collected for 15 muscles of the trunk and lower extremities. Data were filtered and processed to determine the average onset of muscle activation for each motion. A Spearman correlation estimated congruence of activation order between the swing and each exercise. Correlations of each group were pooled with 95% confidence intervals using a random effects meta-analytic strategy. Results. The averaged sequences differed among each athlete tested, but pooled correlations demonstrated a positive association between each exercise and the participants’ natural muscle onset activation sequence. Conclusion. The selected training exercises and Turning Point™ device all partially reproduced our athletes’ averaged muscle onset activation sequences for both sports. The results support consideration of a larger, adequately powered study using this method to quantify to what degree each of the selected exercises is appropriate for use in both golf and tennis.

  1. Measurement of tendon reflexes by surface electromyography in normal subjects

    NARCIS (Netherlands)

    Stam, J.; van Crevel, H.

    1989-01-01

    A simple method for measuring the tendon reflexes was developed. A manually operated, electronic reflex hammer was applied that enabled measurement of the strength of tendon taps. Reflex responses were recorded by surface electromyography. Stimulus-response relations and latencies of tendon reflexes

  2. Basic Hand Gestures Classification Based on Surface Electromyography

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    Aleksander Palkowski

    2016-01-01

    Full Text Available This paper presents an innovative classification system for hand gestures using 2-channel surface electromyography analysis. The system developed uses the Support Vector Machine classifier, for which the kernel function and parameter optimisation are conducted additionally by the Cuckoo Search swarm algorithm. The system developed is compared with standard Support Vector Machine classifiers with various kernel functions. The average classification rate of 98.12% has been achieved for the proposed method.

  3. Evaluation of upper limb muscle fatigue based on surface electromyography.

    Science.gov (United States)

    Zhou, Qianxiang; Chen, Yuhong; Ma, Chao; Zheng, Xiaohui

    2011-10-01

    Fatigue is believed to be a major contributory factor to occupational injuries in machine operators. The development of accurate and usable techniques to measure operator fatigue is therefore important. In this study, we used a novel method based on surface electromyography (sEMG) of the biceps brachii and the Borg scale to evaluate local muscle fatigue in the upper limb after isometric muscle action. Thirteen young males performed isometric actions with the upper limb at different force levels. sEMG activities of the biceps brachii were recorded during the actions. Borg scales were used to evaluate the subjective sensation of local fatigue of the biceps brachii after the actions. sEMG activities were analyzed using the one-third band octave method, and an equation to determine the degree of fatigue was derived based on the relationship between the variable and the Borg scale. The results showed that the relationship could be expressed by a conic curve, and could be used to evaluate muscle fatigue during machine operation.

  4. Recent Observations in Surface Electromyography Recording of Triceps Brachii Muscle in Patients and Athletes

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    Md. Asraf Ali

    2014-01-01

    Full Text Available Objective: To observe and analyse the literature on the use of surface electromyography electrodes, including the shape, size, and metal composition of the electrodes used, the interelectrode distance, and the anatomical locations on the muscle at which the electrodes are placed, for the observation of the triceps brachii muscle activity in patients and athletes.

  5. Reproducibility of 3D kinematics and surface electromyography measurements of mastication

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    Remijn, L.; Groen, B.E.; Speyer, R.; Limbeek, J. van; Sanden, M.W. van der

    2016-01-01

    The aim of this study was to determine the measurement reproducibility for a procedure evaluating the mastication process and to estimate the smallest detectable differences of 3D kinematic and surface electromyography (sEMG) variables. Kinematics of mandible movements and sEMG activity of the

  6. Standardization of surface electromyography utilized to evaluate patients with dysphagia

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    Vaiman Michael

    2007-06-01

    Full Text Available Abstract Backgorund Patients suspected of having swallowing disorders, could highly benefit from simple diagnostic screening before being referred to specialist evaluations. We introduce surface electromyography (sEMG to carry out rapid assessment of such patients and propose suggestions for standardizing sEMGs in order to identify abnormal deglutition. Methods Specifics steps for establishing standards for applying the technique for screening purposes (e.g., evaluation of specific muscles, the requirements for diagnostic sEMG equipment, the sEMG technique itself, and defining the tests suitable for assessing deglutition (e.g., saliva, normal, and excessive swallows and uninterrupted drinking of water are presented in detail. A previously described normative database for single swallowing and drinking and standard approach to analysis was compared to data on the duration and electric activity of muscles involved in deglutition and with sEMG recordings in order to estimate stages of a swallow. Conclusion SEMG of swallowing is a simple and reliable method for screening and preliminary differentiation among dysphagia and odynophagia of various origins. This noninvasive radiation-free examination has a low level of discomfort, and is simple, timesaving and inexpensive to perform. With standardization of the technique and an established normative database, sEMG can serve as a reliable screening method for optimal patient management.

  7. Generation of synthetic surface electromyography signals under fatigue conditions for varying force inputs using feedback control algorithm.

    Science.gov (United States)

    Venugopal, G; Deepak, P; Ghosh, Diptasree M; Ramakrishnan, S

    2017-11-01

    Surface electromyography is a non-invasive technique used for recording the electrical activity of neuromuscular systems. These signals are random, complex and multi-component. There are several techniques to extract information about the force exerted by muscles during any activity. This work attempts to generate surface electromyography signals for various magnitudes of force under isometric non-fatigue and fatigue conditions using a feedback model. The model is based on existing current distribution, volume conductor relations, the feedback control algorithm for rate coding and generation of firing pattern. The result shows that synthetic surface electromyography signals are highly complex in both non-fatigue and fatigue conditions. Furthermore, surface electromyography signals have higher amplitude and lower frequency under fatigue condition. This model can be used to study the influence of various signal parameters under fatigue and non-fatigue conditions.

  8. Muscle fatigue and contraction intensity modulates the complexity of surface electromyography.

    Science.gov (United States)

    Cashaback, Joshua G A; Cluff, Tyler; Potvin, Jim R

    2013-02-01

    Nonlinear dynamical techniques offer a powerful approach for the investigation of physiological time series. Multiscale entropy analyses have shown that pathological and aging systems are less complex than healthy systems and this finding has been attributed to degraded physiological control processes. A similar phenomenon may arise during fatiguing muscle contractions where surface electromyography signals undergo temporal and spectral changes that arise from the impaired regulation of muscle force production. Here we examine the affect of fatigue and contraction intensity on the short and long-term complexity of biceps brachii surface electromyography. To investigate, we used an isometric muscle fatigue protocol (parsed into three windows) and three contraction intensities (% of maximal elbow joint moment: 40%, 70% and 100%). We found that fatigue reduced the short-term complexity of biceps brachii activity during the last third of the fatiguing contraction. We also found that the complexity of surface electromyography is dependent on contraction intensity. Our results show that multiscale entropy is sensitive to muscle fatigue and contraction intensity and we argue it is imperative that both factors be considered when evaluating the complexity of surface electromyography signals. Our data contribute to a converging body of evidence showing that multiscale entropy can quantify subtle information content in physiological time series. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Swallowing in patients with Parkinson's disease: a surface electromyography study.

    Science.gov (United States)

    Ws Coriolano, Maria das Graças; R Belo, Luciana; Carneiro, Danielle; G Asano, Amdore; Al Oliveira, Paulo José; da Silva, Douglas Monteiro; G Lins, Otávio

    2012-12-01

    Our goal was to study deglutition of Parkinson's disease (PD) patients and normal controls (NC) using surface electromyography (sEMG). The study included 15 patients with idiopathic PD and 15 age-matched normal controls. Surface electromyography was collected over the suprahyoid muscle group. Conditions were the following: swallow at once 10 and 20 ml of water and 5 and 10 ml of yogurt of firm consistency, and freely drink 100 ml of water. During swallowing, durations of sEMG were significantly longer in PD patients than in normal controls but no significant differences of amplitudes were found. Eighty percent of the PD patients and 20 % of the NC needed more than one swallow to consume 20 ml of water, while 70 % of the PD patients and none of the NC needed more than one swallow to consume 5 ml of yogurt. PD patients took significantly more time and needed significantly more swallows to drink 100 ml of water than normal controls. We conclude that sEMG might be a simple and useful tool to study and monitor deglutition in PD patients.

  10. Analysis of concentric and eccentric contractions in biceps brachii muscles using surface electromyography signals and multifractal analysis.

    Science.gov (United States)

    Marri, Kiran; Swaminathan, Ramakrishnan

    2016-06-23

    Muscle contractions can be categorized into isometric, isotonic (concentric and eccentric) and isokinetic contractions. The eccentric contractions are very effective for promoting muscle hypertrophy and produce larger forces when compared to the concentric or isometric contractions. Surface electromyography signals are widely used for analyzing muscle activities. These signals are nonstationary, nonlinear and exhibit self-similar multifractal behavior. The research on surface electromyography signals using multifractal analysis is not well established for concentric and eccentric contractions. In this study, an attempt has been made to analyze the concentric and eccentric contractions associated with biceps brachii muscles using surface electromyography signals and multifractal detrended moving average algorithm. Surface electromyography signals were recorded from 20 healthy individuals while performing a single curl exercise. The preprocessed signals were divided into concentric and eccentric cycles and in turn divided into phases based on range of motion: lower (0°-90°) and upper (>90°). The segments of surface electromyography signal were subjected to multifractal detrended moving average algorithm, and multifractal features such as strength of multifractality, peak exponent value, maximum exponent and exponent index were extracted in addition to conventional linear features such as root mean square and median frequency. The results show that surface electromyography signals exhibit multifractal behavior in both concentric and eccentric cycles. The mean strength of multifractality increased by 15% in eccentric contraction compared to concentric contraction. The lowest and highest exponent index values are observed in the upper concentric and lower eccentric contractions, respectively. The multifractal features are observed to be helpful in differentiating surface electromyography signals along the range of motion as compared to root mean square and median

  11. High Quality Acquisition of Surface Electromyography - Conditioning Circuit Design

    Science.gov (United States)

    Shobaki, Mohammed M.; Malik, Noreha Abdul; Khan, Sheroz; Nurashikin, Anis; Haider, Samnan; Larbani, Sofiane; Arshad, Atika; Tasnim, Rumana

    2013-12-01

    The acquisition of Surface Electromyography (SEMG) signals is used for many applications including the diagnosis of neuromuscular diseases, and prosthesis control. The diagnostic quality of the SEMG signal is highly dependent on the conditioning circuit of the SEMG acquisition system. This paper presents the design of an SEMG conditioning circuit that can guarantee to collect high quality signal with high SNR such that it is immune to environmental noise. The conditioning circuit consists of four stages; consisting of an instrumentation amplifier that is used with a gain of around 250; 4th order band pass filter in the 20-500Hz frequency range as the two initial stages. The third stage is an amplifier with adjustable gain using a variable resistance; the gain could be changed from 1000 to 50000. In the final stage the signal is translated to meet the input requirements of data acquisition device or the ADC. Acquisition of accurate signals allows it to be analyzed for extracting the required characteristic features for medical and clinical applications. According to the experimental results, the value of SNR for collected signal is 52.4 dB which is higher than the commercial system, the power spectrum density (PSD) graph is also presented and it shows that the filter has eliminated the noise below 20 Hz.

  12. Detecting Nasal Vowels in Speech Interfaces Based on Surface Electromyography.

    Directory of Open Access Journals (Sweden)

    João Freitas

    Full Text Available Nasality is a very important characteristic of several languages, European Portuguese being one of them. This paper addresses the challenge of nasality detection in surface electromyography (EMG based speech interfaces. We explore the existence of useful information about the velum movement and also assess if muscles deeper down in the face and neck region can be measured using surface electrodes, and the best electrode location to do so. The procedure we adopted uses Real-Time Magnetic Resonance Imaging (RT-MRI, collected from a set of speakers, providing a method to interpret EMG data. By ensuring compatible data recording conditions, and proper time alignment between the EMG and the RT-MRI data, we are able to accurately estimate the time when the velum moves and the type of movement when a nasal vowel occurs. The combination of these two sources revealed interesting and distinct characteristics in the EMG signal when a nasal vowel is uttered, which motivated a classification experiment. Overall results of this experiment provide evidence that it is possible to detect velum movement using sensors positioned below the ear, between mastoid process and the mandible, in the upper neck region. In a frame-based classification scenario, error rates as low as 32.5% for all speakers and 23.4% for the best speaker have been achieved, for nasal vowel detection. This outcome stands as an encouraging result, fostering the grounds for deeper exploration of the proposed approach as a promising route to the development of an EMG-based speech interface for languages with strong nasal characteristics.

  13. Central motor control failure in fibromyalgia: a surface electromyography study.

    Science.gov (United States)

    Casale, Roberto; Sarzi-Puttini, Piercarlo; Atzeni, Fabiola; Gazzoni, Marco; Buskila, Dan; Rainoldi, Alberto

    2009-07-01

    Fibromyalgia (FM) is characterised by diffuse musculoskeletal pain and stiffness at multiple sites, tender points in characteristic locations, and the frequent presence of symptoms such as fatigue. The aim of this study was to assess whether the myoelectrical manifestations of fatigue in patients affected by FM are central or peripheral in origin. Eight female patients aged 55.6 +/- 13.6 years (FM group) and eight healthy female volunteers aged 50.3 +/- 9.3 years (MCG) were studied by means of non-invasive surface electromyography (s-EMG) involving a linear array of 16 electrodes placed on the skin overlying the biceps brachii muscle, with muscle fatigue being evoked by means of voluntary and involuntary (electrically elicited) contractions. Maximal voluntary contractions (MVCs), motor unit action potential conduction velocity distributions (mean +/- SD and skewness), and the mean power frequency of the spectrum (MNF) were estimated in order to assess whether there were any significant differences between the two groups and contraction types. The motor pattern of recruitment during voluntary contractions was altered in the FM patients, who also showed fewer myoelectrical manifestations of fatigue (normalised conduction velocity rate of changes: -0.074 +/- 0.052%/s in FM vs -0.196 +/- 0.133%/s in MCG; normalised MNF rate of changes: -0.29 +/- 0.16%/s in FM vs -0.66 +/- 0.34%/s in MCG). Mean conduction velocity distribution and skewnesses values were higher (p fatigue in FM is the electrophysiological expression of muscle remodelling in terms of the prevalence of slow conducting fatigue-resistant type I fibres. As the only between-group differences concerned voluntary contractions, they are probably more related to central motor control failure than muscle membrane alterations, which suggests pathological muscle fibre remodelling related to altered suprasegmental control.

  14. Central motor control failure in fibromyalgia: a surface electromyography study

    Science.gov (United States)

    Casale, Roberto; Sarzi-Puttini, Piercarlo; Atzeni, Fabiola; Gazzoni, Marco; Buskila, Dan; Rainoldi, Alberto

    2009-01-01

    Background Fibromyalgia (FM) is characterised by diffuse musculoskeletal pain and stiffness at multiple sites, tender points in characteristic locations, and the frequent presence of symptoms such as fatigue. The aim of this study was to assess whether the myoelectrical manifestations of fatigue in patients affected by FM are central or peripheral in origin. Methods Eight female patients aged 55.6 ± 13.6 years (FM group) and eight healthy female volunteers aged 50.3 ± 9.3 years (MCG) were studied by means of non-invasive surface electromyography (s-EMG) involving a linear array of 16 electrodes placed on the skin overlying the biceps brachii muscle, with muscle fatigue being evoked by means of voluntary and involuntary (electrically elicited) contractions. Maximal voluntary contractions (MVCs), motor unit action potential conduction velocity distributions (mean ± SD and skewness), and the mean power frequency of the spectrum (MNF) were estimated in order to assess whether there were any significant differences between the two groups and contraction types. Results The motor pattern of recruitment during voluntary contractions was altered in the FM patients, who also showed fewer myoelectrical manifestations of fatigue (normalised conduction velocity rate of changes: -0.074 ± 0.052%/s in FM vs -0.196 ± 0.133%/s in MCG; normalised MNF rate of changes: -0.29 ± 0.16%/s in FM vs -0.66 ± 0.34%/s in MCG). Mean conduction velocity distribution and skewnesses values were higher (p fatigue in FM is the electrophysiological expression of muscle remodelling in terms of the prevalence of slow conducting fatigue-resistant type I fibres. As the only between-group differences concerned voluntary contractions, they are probably more related to central motor control failure than muscle membrane alterations, which suggests pathological muscle fibre remodelling related to altered suprasegmental control. PMID:19570214

  15. Central motor control failure in fibromyalgia: a surface electromyography study

    Directory of Open Access Journals (Sweden)

    Buskila Dan

    2009-07-01

    Full Text Available Abstract Background Fibromyalgia (FM is characterised by diffuse musculoskeletal pain and stiffness at multiple sites, tender points in characteristic locations, and the frequent presence of symptoms such as fatigue. The aim of this study was to assess whether the myoelectrical manifestations of fatigue in patients affected by FM are central or peripheral in origin. Methods Eight female patients aged 55.6 ± 13.6 years (FM group and eight healthy female volunteers aged 50.3 ± 9.3 years (MCG were studied by means of non-invasive surface electromyography (s-EMG involving a linear array of 16 electrodes placed on the skin overlying the biceps brachii muscle, with muscle fatigue being evoked by means of voluntary and involuntary (electrically elicited contractions. Maximal voluntary contractions (MVCs, motor unit action potential conduction velocity distributions (mean ± SD and skewness, and the mean power frequency of the spectrum (MNF were estimated in order to assess whether there were any significant differences between the two groups and contraction types. Results The motor pattern of recruitment during voluntary contractions was altered in the FM patients, who also showed fewer myoelectrical manifestations of fatigue (normalised conduction velocity rate of changes: -0.074 ± 0.052%/s in FM vs -0.196 ± 0.133%/s in MCG; normalised MNF rate of changes: -0.29 ± 0.16%/s in FM vs -0.66 ± 0.34%/s in MCG. Mean conduction velocity distribution and skewnesses values were higher (p Conclusion The apparent paradox of fewer myoelectrical manifestations of fatigue in FM is the electrophysiological expression of muscle remodelling in terms of the prevalence of slow conducting fatigue-resistant type I fibres. As the only between-group differences concerned voluntary contractions, they are probably more related to central motor control failure than muscle membrane alterations, which suggests pathological muscle fibre remodelling related to altered

  16. Heterogeneity of muscle activation in relation to force direction: a multi-channel surface electromyography study on the triceps surae muscle.

    NARCIS (Netherlands)

    Staudenmann, D.; Kingma, I.; Daffertshofer, A.; Stegeman, D.F.; Dieën, J.H. van

    2009-01-01

    Several skeletal muscles can be divided into sub-modules, called neuromuscular compartments (NMCs), which are thought to be controlled independently and to have distinct biomechanical functions. We looked for distinct muscle activation patterns in the triceps surae muscle (TS) using surface

  17. Heterogeneity of muscle activation in relation to force direction: a multi-channel surface electromyography study on the triceps surae muscle

    NARCIS (Netherlands)

    Staudenmann, D.; Kingma, I.; Daffertshofer, A.; Stegeman, D.F.; van Dieen, J.H.

    2009-01-01

    Several skeletal muscles can be divided into sub-modules, called neuromuscular compartments (NMCs), which are thought to be controlled independently and to have distinct biomechanical functions. We looked for distinct muscle activation patterns in the triceps surae muscle (TS) using surface

  18. Spontaneous mechanical and electrical activities of human calf musculature at rest assessed by repetitive single-shot diffusion-weighted MRI and simultaneous surface electromyography.

    Science.gov (United States)

    Schwartz, Martin; Steidle, Günter; Martirosian, Petros; Ramos-Murguialday, Ander; Preißl, Hubert; Stemmer, Alto; Yang, Bin; Schick, Fritz

    2018-05-01

    Assessment of temporal and spatial relations between spontaneous mechanical activities in musculature (SMAM) at rest as revealed by diffusion-weighted imaging (DWI) and electrical muscular activities in surface EMG (sEMG). Potential influences of static and radiofrequency magnetic fields on muscular activity on sEMG measurements at rest were examined systematically. Series of diffusion-weighted stimulated echo planar imaging were recorded with concurrent sEMG measurements. Electrical activities in sEMG were analyzed by non-parametric Friedman and two-sample Kolmogorov-Smirnov test. Direct correlation of both modalities was investigated by temporal mapping of electrical activity in sEMG to DWI repetition interval. Electrical activities in sEMG and number of visible SMAMs in DWI showed a strong correlation (ρ = 0.9718). High accordance between sEMG activities and visible SMAMs in DWI in a near-surface region around sEMG electrodes was achieved. Characteristics of sEMG activities were almost similar under varying magnetic field conditions. Visible SMAMs in DWI have shown a close and direct relation to concurrent signals recorded by sEMG. MR-related magnetic fields had no significant effects on findings in sEMG. Hence, appearance of SMAMs in DWI should not be considered as imaging artifact or as effects originating from the special conditions of MR examinations. Spatial and temporal distributions of SMAMs indicate characteristics of spontaneous (microscopic) mechanical muscular action at rest. Therefore, DWI techniques should be considered as non-invasive tools for studying physiology and pathophysiology of spontaneous activities in resting muscle. Magn Reson Med 79:2784-2794, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  19. Advanced biofeedback from surface electromyography signals using fuzzy system

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2010-01-01

    The aims of this study were to develop a fuzzy inference-based biofeedback system and investigate its effects when inducing active (shoulder elevation) and passive (relax) pauses on the trapezius muscle electromyographic (EMG) activity during computer work. Surface EMG signals were recorded from...... clavicular, descending (bilateral) and ascending parts of the trapezius muscles during computer work. The fuzzy system readjusted itself based on the history of previous inputs. The effect of feedback was assessed in terms of muscle activation regularity and amplitude. Active pause resulted in non...

  20. Oynophagia in patients after dental extraction: surface electromyography study

    Directory of Open Access Journals (Sweden)

    Nahlieli Oded

    2006-10-01

    Full Text Available Abstract Objectives Surface electromyographic (sEMG studies were performed on 40 adult patients following extraction of lower third and second molars to research the approach and limitations of sEMG evaluation of their odynophagia complaints. Methods Parameters evaluated during swallowing and drinking include the timing, number of swallows per 100 cc of water, and range (amplitude of EMG activity of m. masseter, infrahyoid and submental-submandibular group. The above mentioned variables (mean + standard deviation were measured for the group of dental patients (n = 40 and control group of healthy adults (n = 40. Results The duration of swallows and drinking in all tests showed increase in dental patients' group, in which this tendency is statistically significant. There was no statistically significant difference between male and female adults' duration and amplitude of muscle activity during continuous drinking in both groups (p = 0.05. The mean of electric activity (in μV of m. masseter was significantly lower in the dental patients' group in comparison with control group. The electric activity of submental-submandimular and infrahyoid muscle groups was the same in both groups. Conclusion Surface EMG of swallowing is a simple and reliable noninvasive method for evaluation of odynophagia/dysphagia complaints following dental extraction with low level of discomfort of the examination. The surface EMG studies prove that dysphagia following dental extraction and molar surgery has oral origin, does not affect pharingeal segment and submental-submandibular muscle group. This type of dysphagia has clear EMG signs: increased duration of single swallow, longer drinking time, low range of electric activity of m. masseter, normal range of activity of submental-submandibular muscle group, and the "dry swalow" aftereffect. The data can be used for evaluation of complaints and symptoms, as well as for comparison purposes in pre- and postoperative stages and

  1. Concurrent validity of the pressure biofeedback unit and surface electromyography in measuring transversus abdominis muscle activity in patients with chronic nonspecific low back pain

    OpenAIRE

    Lima,Pedro O. P.; Oliveira,Rodrigo R.; Moura Filho,Alberto G.; Raposo,Maria C. F.; Costa,Leonardo O. P.; Laurentino,Glória E. C.

    2012-01-01

    BACKGROUND: The Pressure biofeedback unit (PBU) is an assessment tool used in clinical practice and research aimed to indirectly analyze the transversus abdominis (TrA) muscle activity. The concurrent validity of the PBU in a clinically relevant sample is still unclear. OBJECTIVE: The purpose of this study was to evaluate the concurrent validity and diagnostic accuracy of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain. METHOD: This study was perfor...

  2. Concurrent validity of the pressure biofeedback unit and surface electromyography in measuring transversus abdominis muscle activity in patients with chronic nonspecific low back pain.

    Science.gov (United States)

    Lima, Pedro O P; Oliveira, Rodrigo R; Moura Filho, Alberto G; Raposo, Maria C F; Costa, Leonardo O P; Laurentino, Glória E C

    2012-01-01

    The Pressure biofeedback unit (PBU) is an assessment tool used in clinical practice and research aimed to indirectly analyze the transversus abdominis (TrA) muscle activity. The concurrent validity of the PBU in a clinically relevant sample is still unclear. The purpose of this study was to evaluate the concurrent validity and diagnostic accuracy of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain. This study was performed using a validation, cross-sectional design. Fifty patients with chronic nonspecific low back pain were recruited for this study. To test the concurrent validity both PBU measures (index test) and superficial electromyographic measures (reference-standard test) were compared and collected by a physical therapist in a series of voluntary contraction maneuvers of TrA muscle. Participants were on average 22 years old, weighed 63.7 kilos, 1.70 meters height and mean low back pain duration was 1.9 years. It was observed a weak and non-significant Phi coefficient (r=0.2, plow sensitivity (60%) and specificity (60%) of the PBU. The positive predictive value was high (0.8) and negative predictive value was low (0.2). Concurrent validity of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain is poor given the low correlation and diagnostic accuracy with superficial EMG.

  3. Surface Electromyography for Speech and Swallowing Systems: Measurement, Analysis, and Interpretation

    Science.gov (United States)

    Stepp, Cara E.

    2012-01-01

    Purpose: Applying surface electromyography (sEMG) to the study of voice, speech, and swallowing is becoming increasingly popular. An improved understanding of sEMG and building a consensus as to appropriate methodology will improve future research and clinical applications. Method: An updated review of the theory behind recording sEMG for the…

  4. Test-retest reliability of trunk motor variability measured by large-array surface electromyography.

    Science.gov (United States)

    Abboud, Jacques; Nougarou, François; Loranger, Michel; Descarreaux, Martin

    2015-01-01

    The objective of this study was to evaluate the test-retest reliability of the trunk muscle activity distribution in asymptomatic participants during muscle fatigue using large-array surface electromyography (EMG). Trunk muscle activity distribution was evaluated twice, with 3 to 4 days between them, in 27 asymptomatic volunteers using large-array surface EMG. Motor variability, assessed with 2 different variables (the centroid coordinates of the root mean square map and the dispersion variable), was evaluated during a low back muscle fatigue task. Test-retest reliability of muscle activity distribution was obtained using Pearson correlation coefficients. A shift in the distribution of EMG amplitude toward the lateral-caudal region of the lumbar erector spinae induced by muscle fatigue was observed. Moderate to very strong correlations were found between both sessions in the last 3 phases of the fatigue task for both motor variability variables, whereas weak to moderate correlations were found in the first phases of the fatigue task only for the dispersion variable. These findings show that, in asymptomatic participants, patterns of EMG activity are less reliable in initial stages of muscle fatigue, whereas later stages are characterized by highly reliable patterns of EMG activity. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

  5. A systematic review of surface electromyography analyses of the bench press movement task

    Science.gov (United States)

    Gołaś, Artur; Blazek, Dusan; Maszczyk, Adam; Wilk, Michał; Pietraszewski, Przemysław; Petr, Miroslav; Uhlir, Petr; Zając, Adam

    2017-01-01

    Background The bench press exercise (BP) plays an important role in recreational and professional training, in which muscle activity is an important multifactorial phenomenon. The objective of this paper is to systematically review electromyography (EMG) studies performed on the barbell BP exercise to answer the following research questions: Which muscles show the greatest activity during the flat BP? Which changes in muscle activity are related to specific conditions under which the BP movement is performed? Strategy PubMed, Scopus, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library were searched through June 10, 2016. A combination of the following search terms was used: bench press, chest press, board press, test, measure, assessment, dynamometer, kinematics and biomechanics. Only original, full-text articles were considered. Results The search process resulted in 14 relevant studies that were included in the discussion. The triceps brachii (TB) and pectoralis major (PM) muscles were found to have similar activity during the BP, which was significantly higher than the activity of the anterior deltoid. During the BP movement, muscle activity changes with exercise intensity, velocity of movement, fatigue, mental focus, movement phase and stability conditions, such as bar vibration or unstable surfaces. Under these circumstances, TB is the most common object of activity change. Conclusions PM and TB EMG activity is more dominant and shows greater EMG amplitude than anterior deltoid during the BP. There are six factors that can influence muscle activity during the BP; however, the most important factor is exercise intensity, which interacts with all other factors. The research on muscle activity in the BP has several unresolved areas, such as clearly and strongly defined guidelines to perform EMG measurements (e.g., how to elaborate with surface EMG limits) or guidelines for the use of exact muscle models. PMID

  6. A systematic review of surface electromyography analyses of the bench press movement task.

    Directory of Open Access Journals (Sweden)

    Petr Stastny

    Full Text Available The bench press exercise (BP plays an important role in recreational and professional training, in which muscle activity is an important multifactorial phenomenon. The objective of this paper is to systematically review electromyography (EMG studies performed on the barbell BP exercise to answer the following research questions: Which muscles show the greatest activity during the flat BP? Which changes in muscle activity are related to specific conditions under which the BP movement is performed?PubMed, Scopus, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL in the Cochrane Library were searched through June 10, 2016. A combination of the following search terms was used: bench press, chest press, board press, test, measure, assessment, dynamometer, kinematics and biomechanics. Only original, full-text articles were considered.The search process resulted in 14 relevant studies that were included in the discussion. The triceps brachii (TB and pectoralis major (PM muscles were found to have similar activity during the BP, which was significantly higher than the activity of the anterior deltoid. During the BP movement, muscle activity changes with exercise intensity, velocity of movement, fatigue, mental focus, movement phase and stability conditions, such as bar vibration or unstable surfaces. Under these circumstances, TB is the most common object of activity change.PM and TB EMG activity is more dominant and shows greater EMG amplitude than anterior deltoid during the BP. There are six factors that can influence muscle activity during the BP; however, the most important factor is exercise intensity, which interacts with all other factors. The research on muscle activity in the BP has several unresolved areas, such as clearly and strongly defined guidelines to perform EMG measurements (e.g., how to elaborate with surface EMG limits or guidelines for the use of exact muscle models.

  7. Reliability of surface electromyography timing parameters in gait in cervical spondylotic myelopathy.

    LENUS (Irish Health Repository)

    Malone, Ailish

    2012-02-01

    The aims of this study were to validate a computerised method to detect muscle activity from surface electromyography (SEMG) signals in gait in patients with cervical spondylotic myelopathy (CSM), and to evaluate the test-retest reliability of the activation times designated by this method. SEMG signals were recorded from rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG), during gait in 12 participants with CSM on two separate test days. Four computerised activity detection methods, based on the Teager-Kaiser Energy Operator (TKEO), were applied to a subset of signals and compared to visual interpretation of muscle activation. The most accurate method was then applied to all signals for evaluation of test-retest reliability. A detection method based on a combined slope and amplitude threshold showed the highest agreement (87.5%) with visual interpretation. With respect to reliability, the standard error of measurement (SEM) of the timing of RF, TA and MG between test days was 5.5% stride duration or less, while the SEM of BF was 9.4%. The timing parameters of RF, TA and MG designated by this method were considered sufficiently reliable for use in clinical practice, however the reliability of BF was questionable.

  8. Combining Electromyography and Tactile Myography to Improve Hand and Wrist Activity Detection in Prostheses

    Directory of Open Access Journals (Sweden)

    Noémie Jaquier

    2017-10-01

    Full Text Available Despite recent advances in prosthetics and assistive robotics in general, robust simultaneous and proportional control of dexterous prosthetic devices remains an unsolved problem, mainly because of inadequate sensorization. In this paper, we study the application of regression to muscle activity, detected using a flexible tactile sensor recording muscle bulging in the forearm (tactile myography—TMG. The sensor is made of 320 highly sensitive cells organized in an array forming a bracelet. We propose the use of Gaussian process regression to improve the prediction of wrist, hand and single-finger activation, using TMG, surface electromyography (sEMG; the traditional approach in the field, and a combination of the two. We prove the effectiveness of the approach for different levels of activations in a real-time goal-reaching experiment using tactile data. Furthermore, we performed a batch comparison between the different forms of sensorization, using a Gaussian process with different kernel distances.

  9. Electromyography Activation Levels of the 3 Gluteus Medius Subdivisions During Manual Strength Testing

    DEFF Research Database (Denmark)

    Otten, Roald; Tol, Johannes L; Holmich, Per

    2015-01-01

    deficits and guide specific rehabilitation programs. However, the optimal positions for assessing the strength and activation of these subdivisions are unknown. OBJECTIVE: The first aim was to establish which strength-testing positions produce the highest surface electromyography (sEMG) activation levels...... different strength-testing positions and analyzed using repeated-measures analysis of variance. RESULTS: Significant differences between testing positions for all 3 GM subdivisions were found. There were significant differences between the tested and the contralateral anterior and middle GM subdivisions (P......STUDY DESIGN: Cross-sectional. CONTEXT: Gluteus medius (GM) muscle dysfunction is associated with overuse injury. The GM is functionally composed of 3 separate subdivisions: anterior, middle, and posterior. Clinical assessment of the GM subdivisions is relevant to detect strength and activation...

  10. The integration of surface electromyography in the clinical decision making process: a case report

    Science.gov (United States)

    Nicholson, W Reg

    1998-01-01

    Objective: To demonstrate how the findings of surface electromyography (S.E.M.G.) were integrated into the clinical decision-making process. Clinical Features: This is a retrospective review of the file of a 27-year-old male suffering from mechanical low back pain. He was evaluated on 3 separate occasions over a 3 year period. History, radiography, functional outcome studies, visual-numerical pain score, pain drawing, physical examination and surface electromyography were utilized in evaluating this patient. Intervention and Outcome: The two clinical interventions of spinal manipulative therapy (S.M.T.) had positive results in that the patient achieved an asymptomatic state and returned to his position of employment. The S.E.M.G. data collected during the industrial assessment, did not provide the outcome that the patient had anticipated. Conclusion: Surface electromyography is a useful clinical tool in the author’s decision-making process for the treatment of mechanical lower back pain. Therapeutic intervention by S.M.T., therapeutic exercises and rating risk factors were influenced by the S.E.M.G. findings.

  11. Surface electromyography assessment of back muscle intrinsic properties.

    Science.gov (United States)

    Larivière, Christian; Arsenault, A Bertrand; Gravel, Denis; Gagnon, Denis; Loisel, Patrick

    2003-08-01

    The purpose of this study was to assess (1) the reliability and (2) the sensitivity to low back pain status and gender of different EMG indices developed for the assessment of back muscle weakness, muscle fiber composition and fatigability. Healthy subjects (men and women) and chronic low back pain patients (men only) performed, in a static dynamometer, maximal and submaximal static trunk extension tasks (short and long duration) to assess weakness, fiber composition and fatigue. Surface EMG signals were recorded from four (bilateral) pairs of back muscles and three pairs of abdominal muscles. To assess reliability of the different EMG parameters, 40 male volunteers (20 controls and 20 chronic low back pain patients) were assessed on three occasions. Reliable EMG indices were achieved for both healthy and chronic low back pain subjects when specific measurement strategies were applied. The EMG parameters used to quantify weakness and fiber composition were insensitive to low back status and gender. The EMG fatigue parameters did not detect differences between genders but unexpectedly, healthy men showed higher fatigability than back pain patients. This result was attributed to the smaller absolute load that was attributed to the patients, a load that was defined relative to their maximal strength, a problematic measure with this population. An attempt was made to predict maximal back strength from anthropometric measurements but this prediction was prone to errors. The main difficulties and some potential solutions related to the assessment of back muscle intrinsic properties were discussed.

  12. Validity and Reliability of Surface Electromyography in the Assessment of Primary Muscle Tension Dysphonia.

    Science.gov (United States)

    Khoddami, Seyyedeh Maryam; Talebian, Saeed; Izadi, Farzad; Ansari, Noureddin Nakhostin

    2017-05-01

    The study aims to evaluate the reliability and the discriminative validity of surface electromyography (sEMG) in the assessment of patients with primary muscle tension dysphonia (MTD). The study design is cross-sectional. Fifteen patients with primary MTD (mean age: 34.07 ± 10.99 years) and 15 healthy volunteers (mean age: 34.53 ± 10.63 years) were included. All participants underwent evaluation of sEMG to record the electrical activity of the thyrohyoid and cricothyroid muscles. The outcome measures were the root mean square (RMS), activity peak, duration, and time to the peak activity, which were obtained during /a/ and /i/ prolongation for test-retest reliability. The test-retest reliability was good to excellent for the RMS and peak activity measures (intraclass correlation coefficient [agreement] [ICC agreement ] = 0.49-0.98). The reliability for the activity duration was poor to excellent (ICC agreement  = 0.19-0.9). Poor test-retest reliability was found for the time to peak measure (ICC agreement  = 0.15-0.37). The standard error of measurement for all sEMG measures was between 0.41 and 2.05. The smallest detectable change (SDC) was calculated between 1.13 and 5.66. The highest SDC values were obtained for the peak and the lowest SDCs were documented for the duration (5.66 and 1.13, respectively). All sEMG measures were not able to discriminate between the MTD patients and healthy subjects (P > 0.05). The sEMG is a reliable tool to measure the RMS, the peak activity, and the activity duration in primary MTD. However, it is not able to discriminate the patients with primary MTD from healthy subjects. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  13. Effect of electrocardiographic contamination on surface electromyography assessment of back muscles.

    Science.gov (United States)

    Hu, Yong; Mak, Joseph N F; Luk, Keith D K

    2009-02-01

    The purpose of this study was to demonstrate the relative effect of electrocardiography (ECG) on back muscle surface electromyography (SEMG) parameters and their corresponding sensitivity in low back pain (LBP) assessment. Back muscle SEMG activities were recorded from 17 healthy subjects and 18 chronic LBP patients under static postures (straight sitting and upright standing), and dynamic action (flexion-extension). ECG cancellation based on independent component analysis (ICA) method was performed. Root mean square (RMS) and median frequency (MF) of raw and denoised SEMG data were computed respectively. Multiple comparisons were then performed. A consistent trend of change (increased MF and decreased RMS) followed ECG removal was noticed. In particular, in SEMG measurements under static postures, a significant decrease in RMS (pcorruption by ECG artifacts on SEMG measurements was found to be more serious and prominent in static postures than that in dynamic action. After ECG removal, significant improvements in the ability of SEMG to discriminate LBP patients from healthy subjects were seen in RMS amplitude recorded while standing (peffect of ECG contamination on back muscles SEMG parameters and LBP assessment.

  14. Implementation of a Surface Electromyography-Based Upper Extremity Exoskeleton Controller Using Learning from Demonstration

    Directory of Open Access Journals (Sweden)

    Ho Chit Siu

    2018-02-01

    Full Text Available Upper-extremity exoskeletons have demonstrated potential as augmentative, assistive, and rehabilitative devices. Typical control of upper-extremity exoskeletons have relied on switches, force/torque sensors, and surface electromyography (sEMG, but these systems are usually reactionary, and/or rely on entirely hand-tuned parameters. sEMG-based systems may be able to provide anticipatory control, since they interface directly with muscle signals, but typically require expert placement of sensors on muscle bodies. We present an implementation of an adaptive sEMG-based exoskeleton controller that learns a mapping between muscle activation and the desired system state during interaction with a user, generating a personalized sEMG feature classifier to allow for anticipatory control. This system is robust to novice placement of sEMG sensors, as well as subdermal muscle shifts. We validate this method with 18 subjects using a thumb exoskeleton to complete a book-placement task. This learning-from-demonstration system for exoskeleton control allows for very short training times, as well as the potential for improvement in intent recognition over time, and adaptation to physiological changes in the user, such as those due to fatigue.

  15. Implementation of a Surface Electromyography-Based Upper Extremity Exoskeleton Controller Using Learning from Demonstration

    Science.gov (United States)

    Arenas, Ana M.; Sun, Tingxiao

    2018-01-01

    Upper-extremity exoskeletons have demonstrated potential as augmentative, assistive, and rehabilitative devices. Typical control of upper-extremity exoskeletons have relied on switches, force/torque sensors, and surface electromyography (sEMG), but these systems are usually reactionary, and/or rely on entirely hand-tuned parameters. sEMG-based systems may be able to provide anticipatory control, since they interface directly with muscle signals, but typically require expert placement of sensors on muscle bodies. We present an implementation of an adaptive sEMG-based exoskeleton controller that learns a mapping between muscle activation and the desired system state during interaction with a user, generating a personalized sEMG feature classifier to allow for anticipatory control. This system is robust to novice placement of sEMG sensors, as well as subdermal muscle shifts. We validate this method with 18 subjects using a thumb exoskeleton to complete a book-placement task. This learning-from-demonstration system for exoskeleton control allows for very short training times, as well as the potential for improvement in intent recognition over time, and adaptation to physiological changes in the user, such as those due to fatigue. PMID:29401754

  16. Evaluation of surgeon's muscle fatigue during thoracoscopic pulmonary lobectomy using interoperative surface electromyography.

    Science.gov (United States)

    Yoon, Seung-Hyun; Jung, Myung-Chul; Park, Seong Yong

    2016-06-01

    The aim of this study was to document the physical stress experienced by a surgeon during thoracoscopic pulmonary lobectomy and mediastinal lymph node dissection for lung cancer by measuring the intraoperative electromyography (EMG). Surface EMG was recorded during 12 cases of thoracoscopic lobectomy. During the operation, 16 channels of a wireless EMG were used to measure muscle activity and fatigue from the bilateral muscles of the splenius capitis (SC), upper trapezius (UT), middle deltoid (MD), flexor carpi radialis (FCR), extensor carpi radialis (ECR), lumbar erector spinae (LES), rectus femoralis (RF), and tibialis anterior (TA). The EMG signals were processed to collect the values of the root mean square for muscle activity and median frequency (MF) for muscle fatigue. All operations were completed without adverse events. The mean operating time was 99.16±35.15 minutes. During the operation, the mean muscle activity of all muscles was 21.91±12.85 mV. High muscle activity was observed in the bilateral FCR and ECR, whereas low muscle activity was observed in the bilateral SC and LES. The final MFs in the bilateral SC and LES were found to be decreased from the initial status, which implied increased muscle fatigue. The muscles of the right and left LES were significantly fatigued by up to 29% and 37% compared to their initial status (P=0.021 and P=0.007, respectively). The MFs of the bilateral LES decreased with time (an average decreases of 0.008/5 minutes, P=0.002 in right LES and 0.004/5 minutes, P=0.018 in left LES). During thoracoscopic lobectomy, muscle fatigue was observed in muscles related to a static posture, such as the bilateral SC, UT, and ES. Further studies are required to investigate the ergonomic adjustments needed to reduce muscle fatigue in these static muscles.

  17. Reliability of surface electromyography in the assessment of paraspinal muscle fatigue: an updated systematic review.

    Science.gov (United States)

    Mohseni Bandpei, Mohammad A; Rahmani, Nahid; Majdoleslam, Basir; Abdollahi, Iraj; Ali, Shabnam Shah; Ahmad, Ashfaq

    2014-09-01

    The purpose of this study was to review the literature to determine whether surface electromyography (EMG) is a reliable tool to assess paraspinal muscle fatigue in healthy subjects and in patients with low back pain (LBP). A literature search for the period of 2000 to 2012 was performed, using PubMed, ProQuest, Science Direct, EMBASE, OVID, CINAHL, and MEDLINE databases. Electromyography, reliability, median frequency, paraspinal muscle, endurance, low back pain, and muscle fatigue were used as keywords. The literature search yielded 178 studies using the above keywords. Twelve articles were selected according to the inclusion criteria of the study. In 7 of the 12 studies, the surface EMG was only applied in healthy subjects, and in 5 studies, the reliability of surface EMG was investigated in patients with LBP or a comparison with a control group. In all of these studies, median frequency was shown to be a reliable EMG parameter to assess paraspinal muscles fatigue. There was a wide variation among studies in terms of methodology, surface EMG parameters, electrode location, procedure, and homogeneity of the study population. The results suggest that there seems to be a convincing body of evidence to support the merit of surface EMG in the assessment of paraspinal muscle fatigue in healthy subject and in patients with LBP. Copyright © 2014 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

  18. Surface Facial Electromyography Reactions to Light-Relevant and Season-Relevant Stimuli in Seasonal Affective Disorder

    National Research Council Canada - National Science Library

    Lindsey, Kathryn T

    2005-01-01

    Facial electromyography (EMG) activity was recorded from the zygomaticus major and corrugator supercilii muscle regions to examine emotion-specific reactivity in 24 currently depressed individuals meeting DSM-IV criteria...

  19. Electromyography Activation Levels of the 3 Gluteus Medius Subdivisions During Manual Strength Testing.

    Science.gov (United States)

    Otten, Roald; Tol, Johannes L; Holmich, Per; Whiteley, Rodney

    2015-08-01

    Cross-sectional. Gluteus medius (GM) muscle dysfunction is associated with overuse injury. The GM is functionally composed of 3 separate subdivisions: anterior, middle, and posterior. Clinical assessment of the GM subdivisions is relevant to detect strength and activation deficits and guide specific rehabilitation programs. However, the optimal positions for assessing the strength and activation of these subdivisions are unknown. The first aim was to establish which strength-testing positions produce the highest surface electromyography (sEMG) activation levels of the individual GM subdivisions. The second aim was to evaluate differences in sEMG activation levels between the tested and contralateral (stabilizing) leg. Twenty healthy physically active male subjects participated in this study. Muscle activity using sEMG was recorded for the GM subdivisions in 8 different strength-testing positions and analyzed using repeated-measures analysis of variance. Significant differences between testing positions for all 3 GM subdivisions were found. There were significant differences between the tested and the contralateral anterior and middle GM subdivisions (P guide specific GM rehabilitation.

  20. Quantifying forearm muscle activity during wrist and finger movements by means of multi-channel electromyography.

    Directory of Open Access Journals (Sweden)

    Marco Gazzoni

    Full Text Available The study of hand and finger movement is an important topic with applications in prosthetics, rehabilitation, and ergonomics. Surface electromyography (sEMG is the gold standard for the analysis of muscle activation. Previous studies investigated the optimal electrode number and positioning on the forearm to obtain information representative of muscle activation and robust to movements. However, the sEMG spatial distribution on the forearm during hand and finger movements and its changes due to different hand positions has never been quantified. The aim of this work is to quantify 1 the spatial localization of surface EMG activity of distinct forearm muscles during dynamic free movements of wrist and single fingers and 2 the effect of hand position on sEMG activity distribution. The subjects performed cyclic dynamic tasks involving the wrist and the fingers. The wrist tasks and the hand opening/closing task were performed with the hand in prone and neutral positions. A sensorized glove was used for kinematics recording. sEMG signals were acquired from the forearm muscles using a grid of 112 electrodes integrated into a stretchable textile sleeve. The areas of sEMG activity have been identified by a segmentation technique after a data dimensionality reduction step based on Non Negative Matrix Factorization applied to the EMG envelopes. The results show that 1 it is possible to identify distinct areas of sEMG activity on the forearm for different fingers; 2 hand position influences sEMG activity level and spatial distribution. This work gives new quantitative information about sEMG activity distribution on the forearm in healthy subjects and provides a basis for future works on the identification of optimal electrode configuration for sEMG based control of prostheses, exoskeletons, or orthoses. An example of use of this information for the optimization of the detection system for the estimation of joint kinematics from sEMG is reported.

  1. Quantifying forearm muscle activity during wrist and finger movements by means of multi-channel electromyography.

    Science.gov (United States)

    Gazzoni, Marco; Celadon, Nicolò; Mastrapasqua, Davide; Paleari, Marco; Margaria, Valentina; Ariano, Paolo

    2014-01-01

    The study of hand and finger movement is an important topic with applications in prosthetics, rehabilitation, and ergonomics. Surface electromyography (sEMG) is the gold standard for the analysis of muscle activation. Previous studies investigated the optimal electrode number and positioning on the forearm to obtain information representative of muscle activation and robust to movements. However, the sEMG spatial distribution on the forearm during hand and finger movements and its changes due to different hand positions has never been quantified. The aim of this work is to quantify 1) the spatial localization of surface EMG activity of distinct forearm muscles during dynamic free movements of wrist and single fingers and 2) the effect of hand position on sEMG activity distribution. The subjects performed cyclic dynamic tasks involving the wrist and the fingers. The wrist tasks and the hand opening/closing task were performed with the hand in prone and neutral positions. A sensorized glove was used for kinematics recording. sEMG signals were acquired from the forearm muscles using a grid of 112 electrodes integrated into a stretchable textile sleeve. The areas of sEMG activity have been identified by a segmentation technique after a data dimensionality reduction step based on Non Negative Matrix Factorization applied to the EMG envelopes. The results show that 1) it is possible to identify distinct areas of sEMG activity on the forearm for different fingers; 2) hand position influences sEMG activity level and spatial distribution. This work gives new quantitative information about sEMG activity distribution on the forearm in healthy subjects and provides a basis for future works on the identification of optimal electrode configuration for sEMG based control of prostheses, exoskeletons, or orthoses. An example of use of this information for the optimization of the detection system for the estimation of joint kinematics from sEMG is reported.

  2. Analysis of progression of fatigue conditions in biceps brachii muscles using surface electromyography signals and complexity based features.

    Science.gov (United States)

    Karthick, P A; Makaram, Navaneethakrishna; Ramakrishnan, S

    2014-01-01

    Muscle fatigue is a neuromuscular condition where muscle performance decreases due to sustained or intense contraction. It is experienced by both normal and abnormal subjects. In this work, an attempt has been made to analyze the progression of muscle fatigue in biceps brachii muscles using surface electromyography (sEMG) signals. The sEMG signals are recorded from fifty healthy volunteers during dynamic contractions under well defined protocol. The acquired signals are preprocessed and segmented in to six equal parts for further analysis. The features, such as activity, mobility, complexity, sample entropy and spectral entropy are extracted from all six zones. The results are found showing that the extracted features except complexity feature have significant variations in differentiating non-fatigue and fatigue zone respectively. Thus, it appears that, these features are useful in automated analysis of various neuromuscular activities in normal and pathological conditions.

  3. Inter-day reliability of surface electromyography recordings of the lumbar part of erector spinae longissimus and trapezius descendens during box lifting

    OpenAIRE

    Brandt, Mikkel; Andersen, Lars Louis; Samani, Afshin; Jakobsen, Markus Due; Madeleine, Pascal

    2017-01-01

    Background Low back pain and neck-shoulder pain are the most reported types of work-related musculoskeletal disorders, and performing heavy lifting at work and working with trunk rotation increase the risk of developing work-related musculoskeletal disorders. Surface electromyography (sEMG) provides information about the electrical activity of muscles. Thus it has the potential to retrieve indirect information about the physical exposure of specific muscles of workers during their actual work...

  4. Design of new multi-channel electrodes for surface electromyography signals for signal-processing.

    Science.gov (United States)

    Kilby, J; Prasad, K; Mawston, G

    2016-08-01

    This paper covers the design aspects of a new multi-channel electrode for the acquisition of surface electromyography signals from a selected muscle. The new multi-channel electrode has 11 pins where the monopolar signals produced will be configured in a software either as Linear array or Laplacian configuration. The design specification of the pre-amplifier ideally was to have a voltage gain of 500 with bandpass filtering of 5 Hz-1 kHz. The final design of the pre-amplifier circuit using an INA 118 instrumentation amplifier was built and tested to give values for voltage gain of 484 with bandpass filtering of 6.8 Hz-1.02 kHz. The software configuration that gives clearer and more defined signals in terms of motor unit action potentials for future signal processing is the Laplacian rather than Linear array.

  5. Estimation of muscle fatigue by ratio of mean frequency to average rectified value from surface electromyography.

    Science.gov (United States)

    Fernando, Jeffry Bonar; Yoshioka, Mototaka; Ozawa, Jun

    2016-08-01

    A new method to estimate muscle fatigue quantitatively from surface electromyography (EMG) is proposed. The ratio of mean frequency (MNF) to average rectified value (ARV) is used as the index of muscle fatigue, and muscle fatigue is detected when MNF/ARV falls below a pre-determined or pre-calculated baseline. MNF/ARV gives larger distinction between fatigued muscle and non-fatigued muscle. Experiment results show the effectiveness of our method in estimating muscle fatigue more correctly compared to conventional methods. An early evaluation based on the initial value of MNF/ARV and the subjective time when the subjects start feeling the fatigue also indicates the possibility of calculating baseline from the initial value of MNF/ARV.

  6. [Analysis of the Muscle Fatigue Based on Band Spectrum Entropy of Multi-channel Surface Electromyography].

    Science.gov (United States)

    Liu, Jian; Zou, Renling; Zhang, Dongheng; Xu, Xiulin; Hu, Xiufang

    2016-06-01

    Exercise-induced muscle fatigue is a phenomenon that the maximum voluntary contraction force or power output of muscle is temporarily reduced due to muscular movement.If the fatigue is not treated properly,it will bring about a severe injury to the human body.With multi-channel collection of lower limb surface electromyography signals,this article analyzes the muscle fatigue by adoption of band spectrum entropy method which combined electromyographic signal spectral analysis and nonlinear dynamics.The experimental result indicated that with the increase of muscle fatigue,muscle signal spectrum began to move to low frequency,the energy concentrated,the system complexity came down,and the band spectrum entropy which reflected the complexity was also reduced.By monitoring the entropy,we can measure the degree of muscle fatigue,and provide an indicator to judge fatigue degree for the sports training and clinical rehabilitation training.

  7. Muscle conduction velocity, surface electromyography variables, and echo intensity during concentric and eccentric fatigue.

    Science.gov (United States)

    Gonzalez-Izal, Miriam; Lusa Cadore, Eduardo; Izquierdo, Mikel

    2014-03-01

    Concentric (CON) and eccentric (ECC) contractions may involve different mechanisms related to changes in sarcolemma status and the consequent alteration of action potential transmission along muscle fibers. Muscle conduction velocity (CV), surface electromyography signal (sEMG), muscle quality, and blood lactate concentrations were analyzed during CON and ECC actions. Compared with ECC, the CON protocol resulted in greater muscle force losses, blood lactate concentrations, and changes in sEMG parameters. Similar reductions in CV were detected in both protocols. Higher echo intensity values were observed 2 days after ECC due to greater muscle damage. The effects of the muscle damage produced by ECC exercise on the transmission of action potentials along muscle fibers (measured as the CV) may be comparable with the effects of hydrogen accumulation produced by CON exercise (related to greater lactate concentrations), which causes greater force loss and change in other sEMG variables during CON than during ECC actions.

  8. Estimation of muscle fatigue using surface electromyography and near-infrared spectroscopy.

    Science.gov (United States)

    Taelman, Joachim; Vanderhaegen, Joke; Robijns, Mieke; Naulaers, Gunnar; Spaepen, Arthur; Van Huffel, Sabine

    2011-01-01

    This study looks at various parameters, derived from surface electromyography (sEMG) and Near Infrared Spectroscopy (NIRS) and their relationship in muscle fatigue during a static elbow flexion until exhaustion as well as during a semidynamic exercise.We found a linear increasing trend for a corrected amplitude parameter and a linear decreasing slope for the frequency content of the sEMG signal. The tissue oxygenation index (TOI) extracted from NIRS recordings showed a four-phase response for all the subjects. A strong correlation between frequency content of the sEMG signal and TOI was established. We can conclude that both sEMG and NIRS give complementary information concerning muscle fatigue.

  9. Effect of the Enveloppe Linguale Nocturne on atypical swallowing: surface electromyography and computerised postural test evaluation.

    Science.gov (United States)

    Ciavarella, D; Mastrovincenzo, M; Sabatucci, A; Parziale, V; Chimenti, C

    2010-09-01

    Swallowing is a neuromuscular mechanism regulated by many nervous reflex arcs. Persistence of child swallowing at the end of dental eruption is called atypical swallowing (AS). This condition is related to a dysfunction of vertical maxillary growth called open bite. The authors treated this malocclusion with the Enveloppe Linguale Nocturne (ELN), or tongue positioner, created by Dr. Bonnet. The aim of this work is to evaluate the effect of ELN on swallowing and the postural variation obtained by its use. Seven patients affected by AS were evaluated. Surface Electromyography (sEMG) testing was performed on each patient with different tongue positions, and swallowing was evaluated with and without the ELN. A surface Electromyograph (Biopack) with 8 channels was used (4 channels for the right muscles and 4 for the left) on 4 groups of muscles: temporals, masseters (MM), submental (SUB) and sternocleidmastoids. On each patient a postural test using a computerised Postural test (Lizard) was also performed. Statistical analysis was done using the Graph pad Instat 3 both for sEMG activity and for computerised postural analysis. All seven subjects had different results in the sEMG and footrest tests. The sEMG test results indicated that muscle activation and swallowing duration varied greatly with the use of ELN, with a reduction of time of swallow act (p = 0.002) and variation in contraction of muscles. Mean MM activation was higher without ELN than in tests performed with the appliance (p = 0.002). Mean SUB activation was higher with than without ELN (p = 0.0033). ELN has a therapeutic effect on posture too. Computerised postural test without device showed in all patients an alteration of barycentre as well as an elevated oscillatory record (A mmq; V mms). With ELN footrest kilogram difference (p = 0.0110), Oscillatory Area (P = 0.0102) and velocity of oscillation (P = 0.0102) presented a great reduction in respect to patients record without ELN. With ELN the tongue

  10. SURFACE ELECTROMYOGRAPHY OF MASSETER AND TEMPORAL MUSCLES WITH USE PERCENTAGE WHILE CHEWING ON CANDIDATES FOR GASTROPLASTY.

    Science.gov (United States)

    Santos, Andréa Cavalcante Dos; Silva, Carlos Antonio Bruno da

    Surface electromyography identifies changes in the electrical potential of the muscles during each contraction. The percentage of use is a way to treat values enabling comparison between groups. To analyze the electrical activity and the percentage of use of masseter and temporal muscles during chewing in candidates for gastric bypass. It was used Surface Electromyography Miotool 200,400 (Miotec (r), Porto Alegre/RS, Brazil) integrated with Miograph 2.0 software, involving patients between 20-40 years old. Were included data on electrical activity simultaneously and in pairs of temporal muscle groups and masseter at rest, maximum intercuspation and during the chewing of food previously classified. Were enrolled 39 patients (59 women), mean age 27.1+/-5.7. The percentage of use focused on temporal muscle, in a range of 11-20, female literacy (n=11; 47.82) on the left side and 15 (65.21) on the right-hand side. In the male, nine (56.25) at left and 12 (75.00) on the right-hand side. In masseter, also in the range of 11 to 20, female literacy (n=10; 43.48) on the left side and 11 (47.83) on the right-hand side. In the male, nine (56.25) at left and eight (50.00) on the right-hand side. 40-50% of the sample showed electrical activity in muscles (masseter and temporal) with variable values, and after processing into percentage value, facilitating the comparison of load of used electrical activity between the group, as well as usage percentage was obtained of muscle fibers 11-20% values involving, representing a range that is considered as a reference to the group studied. The gender was not a variable. A eletromiografia de superfície identifica variações dos potenciais elétricos dos músculos durante cada contração realizada. O percentual de uso é uma forma de tratar valores possibilitando comparação entre grupos. Analisar a atividade elétrica e o percentual de uso dos músculos masséteres e temporais durante a mastigação em candidatos à gastroplastia

  11. Discrete wavelet transform analysis of surface electromyography for the fatigue assessment of neck and shoulder muscles.

    Science.gov (United States)

    Chowdhury, Suman Kanti; Nimbarte, Ashish D; Jaridi, Majid; Creese, Robert C

    2013-10-01

    Assessment of neuromuscular fatigue is essential for early detection and prevention of risks associated with work-related musculoskeletal disorders. In recent years, discrete wavelet transform (DWT) of surface electromyography (SEMG) has been used to evaluate muscle fatigue, especially during dynamic contractions when the SEMG signal is non-stationary. However, its application to the assessment of work-related neck and shoulder muscle fatigue is not well established. Therefore, the purpose of this study was to establish DWT analysis as a suitable method to conduct quantitative assessment of neck and shoulder muscle fatigue under dynamic repetitive conditions. Ten human participants performed 40min of fatiguing repetitive arm and neck exertions while SEMG data from the upper trapezius and sternocleidomastoid muscles were recorded. The ten of the most commonly used wavelet functions were used to conduct the DWT analysis. Spectral changes estimated using power of wavelet coefficients in the 12-23Hz frequency band showed the highest sensitivity to fatigue induced by the dynamic repetitive exertions. Although most of the wavelet functions tested in this study reasonably demonstrated the expected power trend with fatigue development and recovery, the overall performance of the "Rbio3.1" wavelet in terms of power estimation and statistical significance was better than the remaining nine wavelets. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Normalised Mutual Information of High-Density Surface Electromyography during Muscle Fatigue

    Directory of Open Access Journals (Sweden)

    Adrian Bingham

    2017-12-01

    Full Text Available This study has developed a technique for identifying the presence of muscle fatigue based on the spatial changes of the normalised mutual information (NMI between multiple high density surface electromyography (HD-sEMG channels. Muscle fatigue in the tibialis anterior (TA during isometric contractions at 40% and 80% maximum voluntary contraction levels was investigated in ten healthy participants (Age range: 21 to 35 years; Mean age = 26 years; Male = 4, Female = 6. HD-sEMG was used to record 64 channels of sEMG using a 16 by 4 electrode array placed over the TA. The NMI of each electrode with every other electrode was calculated to form an NMI distribution for each electrode. The total NMI for each electrode (the summation of the electrode’s NMI distribution highlighted regions of high dependence in the electrode array and was observed to increase as the muscle fatigued. To summarise this increase, a function, M(k, was defined and was found to be significantly affected by fatigue and not by contraction force. The technique discussed in this study has overcome issues regarding electrode placement and was used to investigate how the dependences between sEMG signals within the same muscle change spatially during fatigue.

  13. Exercise muscle fatigue detection system implementation via wireless surface electromyography and empirical mode decomposition.

    Science.gov (United States)

    Chang, Kang-Ming; Liu, Shing-Hong; Wang, Jia-Jung; Cheng, Da-Chuan

    2013-01-01

    Surface electromyography (sEMG) is an important measurement for monitoring exercise and fitness. A wireless Bluetooth transmission sEMG measurement system with a sampling frequency of 2 KHz is developed. Traditional muscle fatigue is detected from the median frequency of the sEMG power spectrum. The regression slope of the linear regression of median frequency is an important muscle fatigue index. As fatigue increases, the power spectrum of the sEMG shifts toward lower frequencies. The goal of this study is to evaluate the sensitivity of empirical mode decomposition (EMD) quantifying the electrical manifestations of the local muscle fatigue during exercising in health people. We also compared this method with the raw data and discrete wavelet transform (DWT). Five male and five female volunteers participated. Each subject was asked to run on a multifunctional pedaled elliptical trainer for about 30 minutes, twice a week, and there were a total of six recording times for each subject with a wireless EMG recording system. The results show that sensitivity of the highest frequency component of EMD is better than the highest frequency component of DWT, and raw data.

  14. Surface electromyography based muscle fatigue analysis for stroke patients at different Brunnstrom stages.

    Science.gov (United States)

    Yinjun Tu; Zhe Zhang; Xudong Gu; Qiang Fang

    2016-08-01

    Muscle fatigue analysis has been an important topic in sport and rehabilitation medicine due to its role in muscle performance evaluation and pathology investigation. This paper proposes a surface electromyography (sEMG) based muscle fatigue analysis approach which was specifically designed for stroke rehabilitation applications. 14 stroke patients from 5 different Brunnstrom recovery stage groups were involved in the experiment and features including median frequency and mean power frequency were extracted from the collected sEMG samples for investigation. After signal decomposition, the decline of motor unit firing rate of patients from different groups had also been studied. Statistically significant presence of fatigue had been observed in deltoideus medius and extensor digitorum communis of patients at early recovery stages (P0.01). It had also been discovered that the motor unit firing frequency declines with a range positively correlated to the recovery stage during repetitive movements. Based on the experiment result, it can be verified that as the recovery stage increases, the central nervous system's control ability strengthens and the patient motion becomes more stable and resistive to fatigue.

  15. Heart rate variability and surface electromyography of trained cyclists at different cadences

    Directory of Open Access Journals (Sweden)

    Bruno Saraiva

    2016-06-01

    Full Text Available The heart rate variability (HRV and surface electromyography (sEMG are important tools in the evaluation of cardiac autonomic system and neuromuscular parameters, respectively. The aim of the study was to evaluate the behavior of HRV and sEMG of the vastus lateralis in two exercise protocols on a cycle ergometer at 60 and 80 rpm. Eight healthy men cyclists who have trained for at least two years were evaluated. Reduction was observed followed by stabilization of RMSSD and SDNN indices of HRV (p<0.05 along with increases in the amplitude of the sEMG signal (p<0.05 in both protocols. Significant correlations were observed between the responses of HRV and sEMG in the cadence of 60 rpm (RMSSD and sEMG: r = -0.42, p=0.03; SDNN and sEMG: r = -0.45, p=0.01 and 80 rpm (RMSSD and sEMG: r = -0.47, p=0.02; SDNN and sEMG: r = -0.49, p=0.01, yet no difference was observed for these variables between the two protocols. We concluded that the parasympathetic cardiac responses and sEMG are independent of cadences applied at the same power output.

  16. Support vectors machine classification of surface electromyography for non-invasive naturally controlled hand prostheses.

    Science.gov (United States)

    Moura, Karina O A; Favieiro, Gabriela W; Balbinot, Alexandre

    2016-08-01

    The scientific researches in human rehabilitation techniques have continually evolved to offer again the mobility and freedom lost to disability. Many systems managed by myoelectric signals intended to mimic the movement of the human arm still have results considered partial, which makes it subject of many researches. The use of Natural Interfaces Signal Processing methods makes possible to design systems capable of offering prosthesis in a more natural and intuitive way. This paper presents a study investigating the use of forearm surface electromyography (sEMG) signals for classification of specific movements of hand using 12 sEMG channels and support vector machine (SVM). The system acquired the sEMG signal using a virtual model as a visual stimulus in order to demonstrate to the volunteer the hand movements which must be replicated by them. The Root Mean Square (RMS) value feature is extracted of the signal and it serves as input data for the classification with SVM. The classification stage used three types of kernel functions (linear, polynomial, radial basis) for comparison of the results. The average accuracy reached for the classification of seventeen distinct movements of 83.7% was achieved using the SVM linear classifier, 80.8% was achieved using the SVM polynomial classifier and 85.1% was achieved using the SVM radial basis classifier.

  17. Textile Electrodes Embedded in Clothing: A Practical Alternative to Traditional Surface Electromyography when Assessing Muscle Excitation during Functional Movements.

    Science.gov (United States)

    Colyer, Steffi L; McGuigan, Polly M

    2018-03-01

    Textile electromyography (EMG) electrodes embedded in clothing allow muscle excitation to be recorded in previously inaccessible settings; however, their ability to accurately and reliably measure EMG during dynamic tasks remains largely unexplored. To quantify the validity and reliability of textile electrodes, 16 recreationally active males completed two identical testing sessions, within which three functional movements (run, cycle and squat) were performed twice: once wearing EMG shorts (measuring quadriceps, hamstrings and gluteals myoelectric activity) and once with surface EMG electrodes attached to the vastus lateralis, biceps femoris and gluteus maximus. EMG signals were identically processed to provide average rectified EMG (normalized to walking) and excitation length. Results were compared across measurement systems and demonstrated good agreement between the magnitude of muscle excitation when EMG activity was lower, but agreement was poorer when excitation was higher. The length of excitation bursts was consistently longer when measured using textile vs. surface EMG electrodes. Comparable between-session (day-to-day) repeatability was found for average rectified EMG (mean coefficient of variation, CV: 42.6 and 41.2%) and excitation length (CV: 12.9 and 9.8%) when using textile and surface EMG, respectively. Additionally, similar within-session repeatability (CV) was recorded for average rectified EMG (13.8 and 14.1%) and excitation length (13.0 and 12.7%) for textile and surface electrodes, respectively. Generally, textile EMG electrodes appear to be capable of providing comparable muscle excitation information and reproducibility to surface EMG during dynamic tasks. Textile EMG shorts could therefore be a practical alternative to traditional laboratory-based methods allowing muscle excitation information to be collected in more externally-valid training environments.

  18. Textile Electrodes Embedded in Clothing: A Practical Alternative to Traditional Surface Electromyography when Assessing Muscle Excitation during Functional Movements

    Directory of Open Access Journals (Sweden)

    Steffi L. Colyer, Polly M. McGuigan

    2018-03-01

    Full Text Available Textile electromyography (EMG electrodes embedded in clothing allow muscle excitation to be recorded in previously inaccessible settings; however, their ability to accurately and reliably measure EMG during dynamic tasks remains largely unexplored. To quantify the validity and reliability of textile electrodes, 16 recreationally active males completed two identical testing sessions, within which three functional movements (run, cycle and squat were performed twice: once wearing EMG shorts (measuring quadriceps, hamstrings and gluteals myoelectric activity and once with surface EMG electrodes attached to the vastus lateralis, biceps femoris and gluteus maximus. EMG signals were identically processed to provide average rectified EMG (normalized to walking and excitation length. Results were compared across measurement systems and demonstrated good agreement between the magnitude of muscle excitation when EMG activity was lower, but agreement was poorer when excitation was higher. The length of excitation bursts was consistently longer when measured using textile vs. surface EMG electrodes. Comparable between-session (day-to-day repeatability was found for average rectified EMG (mean coefficient of variation, CV: 42.6 and 41.2% and excitation length (CV: 12.9 and 9.8% when using textile and surface EMG, respectively. Additionally, similar within-session repeatability (CV was recorded for average rectified EMG (13.8 and 14.1% and excitation length (13.0 and 12.7% for textile and surface electrodes, respectively. Generally, textile EMG electrodes appear to be capable of providing comparable muscle excitation information and reproducibility to surface EMG during dynamic tasks. Textile EMG shorts could therefore be a practical alternative to traditional laboratory-based methods allowing muscle excitation information to be collected in more externally-valid training environments.

  19. Fatiguing Effects on the Multi-Scale Entropy of Surface Electromyography in Children with Cerebral Palsy

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    Tong Hong

    2016-05-01

    Full Text Available The objective of this study was to investigate the effects of muscle fatigue on the multi-scale entropy of surface electromyography (EMG in children with cerebral palsy (CP and typical development (TD. Sixteen CP children and eighteen TD children participated in experiments where they performed upper limb cyclic lifting tasks following a muscle fatiguing process, while the surface EMG signals were recorded from their upper trapezius muscles. Multi-scale entropy (MSE analyses of the surface EMG were applied by calculating sample entropy (SampEn on individual intrinsic mode functions (IMFs adaptively generated by empirical mode decomposition (EMD of the original signal. The declining degree of the resultant MSE curve was found to reflect muscle fatigue level for all subjects, with its slope (purposely calculated over the first four scales increasing significantly as the fatigue level increased. Further, such a slope increase was less significant for CP children as compared with TD children. Our findings confirmed that the decrease of muscle fiber conduction velocity (MFCV and the increase of motor unit synchronization may be two possible factors induced by muscle fatigue, and further indicated that there appear to be some neuromuscular changes (such as MFCV decrease, motor unit synchronization increase, motor unit firing rates reduction, selective loss of larger motor units that occur as a result of cerebral palsy. These changes may account for experimentally observed difference in fatiguing effects between subject groups. Our study provides an investigative tool to assess muscle fatigue as well as to help reveal complex neuropathological changes underlying the motor impairments of CP children.

  20. Analysis of endodontist posture utilizing cinemetry, surface electromyography and ergonomic checklists.

    Science.gov (United States)

    Onety, Geraldo Celso da Silva; Leonel, Daniel Vilela; Saquy, Paulo César; Silva, Gabriel Pádua da; Ferreira, Bruno; Varise, Tiago Gilioli; Sousa, Luiz Gustavo de; Verri, Edson Donizetti; Siéssere, Selma; Semprini, Marisa; Nepomuceno, Victor Rodrigues; Regalo, Simone Cecilio Hallak

    2014-01-01

    The postural risk factors for dentists include the ease of vision in the workplace, cold, vibration and mechanical pressure in tissues, incorrect posture, functional fixity, cognitive requirements and work-related organizational and psychosocial factors. The objective was to analyze the posture of endodontists at the workplace. Eighteen right-handed endodontists aged 25 to 60 years (34±3) participated in the study. Electromyography, kinemetry, ergonomic scales (RULA and Couto's checklist) and biophotogrammetry were used to analyze the posture of endodontists during root canal treatment of the maxillary right first and second molars using rotary and manual instrumentation. The variations observed in the electromyographic activities during the performance of rotary and manual techniques suggest that the fibers of the longissimus region, anterior and medium deltoid, medium trapezium, biceps, triceps brachii, brachioradialis and short thumb abductor muscles underwent adaptations to provide more accurate functional movements. Computerized kinemetry and biophotogrammetry showed that, as far as posture is concerned, rotary technique was more demanding than the manual technique. In conclusion, the group of endodontists evaluated in this study exhibited posture disorders regardless of whether the rotary or manual technique was used.

  1. Correlation analysis between surface electromyography and continuous-wave near-infrared spectroscopy parameters during isometric exercise to volitional fatigue

    OpenAIRE

    ŞAYLİ, Ömer; AKIN, Ata; ÇOTUK, Hasan Birol

    2014-01-01

    In this study, the process of muscular fatigue was examined using surface electromyography (sEMG) and continuous-wave near-infrared spectroscopy (cw-NIRS) simultaneously during an isometric hand grip exercise at 50% and 75% of the maximal voluntary contraction (MVC), sustained until volitional fatigue. The mean frequency of the sEMG decreased during the whole exercise, whereas the root mean square had a tendency to increase. Oxyhemoglobin/deoxyhemoglobin concentration changes computed ...

  2. Correlative Evaluation of Mental and Physical Workload of Laparoscopic Surgeons Based on Surface Electromyography and Eye-tracking Signals.

    Science.gov (United States)

    Zhang, Jian-Yang; Liu, Sheng-Lin; Feng, Qing-Min; Gao, Jia-Qi; Zhang, Qiang

    2017-09-11

    Surgeons' mental and physical workloads are major focuses of operating room (OR) ergonomics, and studies on this topic have generally focused on either mental workload or physical workload, ignoring the interaction between them. Previous studies have shown that physically demanding work may affect mental performance and may be accompanied by impaired mental processing and decreased performance. In this study, 14 participants were recruited to perform laparoscopic cholecystectomy (LC) procedures in a virtual simulator. Surface electromyography (sEMG) signals of the bilateral trapezius, bicipital, brachioradialis and flexor carpi ulnaris (FCU) muscles and eye-tracking signals were acquired during the experiment. The results showed that the least square means of muscle activity during the LC phases of surgery in an all-participants mixed effects model were 0.79, 0.81, and 0.98, respectively. The observed muscle activities in the different phases exhibited some similarity, while marked differences were found between the forearm bilateral muscles. Regarding mental workload, significant differences were observed in pupil dilation between the three phases of laparoscopic surgery. The mental and physical workloads of laparoscopic surgeons do not appear to be generally correlated, although a few significant negative correlations were found. This result further indicates that mental fatigue does markedly interfere with surgeons' operating movements.

  3. Comparison of regression models for estimation of isometric wrist joint torques using surface electromyography

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    Menon Carlo

    2011-09-01

    Full Text Available Abstract Background Several regression models have been proposed for estimation of isometric joint torque using surface electromyography (SEMG signals. Common issues related to torque estimation models are degradation of model accuracy with passage of time, electrode displacement, and alteration of limb posture. This work compares the performance of the most commonly used regression models under these circumstances, in order to assist researchers with identifying the most appropriate model for a specific biomedical application. Methods Eleven healthy volunteers participated in this study. A custom-built rig, equipped with a torque sensor, was used to measure isometric torque as each volunteer flexed and extended his wrist. SEMG signals from eight forearm muscles, in addition to wrist joint torque data were gathered during the experiment. Additional data were gathered one hour and twenty-four hours following the completion of the first data gathering session, for the purpose of evaluating the effects of passage of time and electrode displacement on accuracy of models. Acquired SEMG signals were filtered, rectified, normalized and then fed to models for training. Results It was shown that mean adjusted coefficient of determination (Ra2 values decrease between 20%-35% for different models after one hour while altering arm posture decreased mean Ra2 values between 64% to 74% for different models. Conclusions Model estimation accuracy drops significantly with passage of time, electrode displacement, and alteration of limb posture. Therefore model retraining is crucial for preserving estimation accuracy. Data resampling can significantly reduce model training time without losing estimation accuracy. Among the models compared, ordinary least squares linear regression model (OLS was shown to have high isometric torque estimation accuracy combined with very short training times.

  4. Analysis of Muscle Fatigue Progression using Cyclostationary Property of Surface Electromyography Signals.

    Science.gov (United States)

    Karthick, P A; Venugopal, G; Ramakrishnan, S

    2016-01-01

    Analysis of neuromuscular fatigue finds various applications ranging from clinical studies to biomechanics. Surface electromyography (sEMG) signals are widely used for these studies due to its non-invasiveness. During cyclic dynamic contractions, these signals are nonstationary and cyclostationary. In recent years, several nonstationary methods have been employed for the muscle fatigue analysis. However, cyclostationary based approach is not well established for the assessment of muscle fatigue. In this work, cyclostationarity associated with the biceps brachii muscle fatigue progression is analyzed using sEMG signals and Spectral Correlation Density (SCD) functions. Signals are recorded from fifty healthy adult volunteers during dynamic contractions under a prescribed protocol. These signals are preprocessed and are divided into three segments, namely, non-fatigue, first muscle discomfort and fatigue zones. Then SCD is estimated using fast Fourier transform accumulation method. Further, Cyclic Frequency Spectral Density (CFSD) is calculated from the SCD spectrum. Two features, namely, cyclic frequency spectral area (CFSA) and cyclic frequency spectral entropy (CFSE) are proposed to study the progression of muscle fatigue. Additionally, degree of cyclostationarity (DCS) is computed to quantify the amount of cyclostationarity present in the signals. Results show that there is a progressive increase in cyclostationary during the progression of muscle fatigue. CFSA shows an increasing trend in muscle fatiguing contraction. However, CFSE shows a decreasing trend. It is observed that when the muscle progresses from non-fatigue to fatigue condition, the mean DCS of fifty subjects increases from 0.016 to 0.99. All the extracted features found to be distinct and statistically significant in the three zones of muscle contraction (p < 0.05). It appears that these SCD features could be useful in the automated analysis of sEMG signals for different neuromuscular conditions.

  5. Muscle fatigue in women with primary biliary cirrhosis: Spectral analysis of surface electromyography

    Science.gov (United States)

    Biagini, Maria Rosa; Tozzi, Alessandro; Grippo, Antonello; Galli, Andrea; Milani, Stefano; Amantini, Aldo

    2006-01-01

    AIM: To evaluate the myoelectric manifestations of peripheral fatigability in patients with primary biliary cirrhosis in comparison to healthy subjects. METHODS: Sixteen women with primary biliary cirrhosis without comorbidity and 13 healthy women matched for age and body mass index (BMI) completed the self-reported questionnaire fatigue impact scale. All subjects underwent surface electromyography assessment of peripheral fatigability. Anterior tibial muscle isometric voluntary contraction was executed for 20 s at 80% of maximal voluntary isometric contraction. During the exercise electromyographic signal series were recorded and root mean square (expression of central drive) as well as mean and median of electromyographic signal frequency spectrum (estimates of muscle fatigability) were computed. Each subject executed the trial two times. EMG parameters were normalized, then linear regression was applied and slopes were calculated. RESULTS: Seven patients were fatigued (median fatigue impact scale score: 38, range: 26-66) and 9 were not fatigued (median fatigue impact scale score: 7, range: 0-17). The maximal voluntary isometric contraction was similar in patients (82, 54-115 N) and controls (87, 74-101 N), and in patients with high (81, 54-115 N) and low fatigue impact scale scores (86, 65-106 N). Root mean square as well as mean and median of frequency spectrum slopes were compared with the Mann-Whitney U test, and no significant difference was found between fatigued and non-fatigued patients and controls. CONCLUSION: No instrumental evidence of peripheral fatigability can be found in women with primary biliary cirrhosis but no comorbidity, suggesting that fatigue in such patients may be of central origin. PMID:16937530

  6. Surface electromyography as a screening method for evaluation of dysphagia and odynophagia

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    Eviatar Ephraim

    2009-02-01

    Full Text Available Abstract Objective Patients suspected of having swallowing disorders, could highly benefit from simple diagnostic screening before being referred to specialist evaluations. The article analyzes various instrumental methods of dysphagia assessment, introduces surface electromyography (sEMG to carry out rapid assessment of such patients, and debates proposed suggestions for sEMG screening protocol in order to identify abnormal deglutition. Data sources Subject related books and articles from 1813 to 2007 were obtained through library search, MEDLINE (1949–2007 and EMBASE (1975–2007. Methods Specifics steps for establishing the protocol for applying the technique for screening purposes (e.g., evaluation of specific muscles, the requirements for diagnostic sEMG equipment, the sEMG technique itself, and defining the tests suitable for assessing deglutition (e.g., saliva, normal, and excessive swallows and uninterrupted drinking of water are presented in detail. SEMG is compared with other techniques in terms of cost, timing, involvement of radiation, etc. Results According to the published data, SEMG of swallowing is a simple and reliable method for screening and preliminary differentiation among dysphagia and odynophagia of various origins. This noninvasive radiation-free examination has a low level of discomfort, and is simple, time-saving and inexpensive to perform. The major weakness of the method seems to be inability for precise diagnostic of neurologically induced dysphagia. Conclusion With standardization of the technique and an established normative database, sEMG might serve as a reliable screening method for optimal patient management but cannot serve for proper investigation of neurogenic dysphagia.

  7. Surface electromyography as a screening method for evaluation of dysphagia and odynophagia

    Science.gov (United States)

    Vaiman, Michael; Eviatar, Ephraim

    2009-01-01

    Objective Patients suspected of having swallowing disorders, could highly benefit from simple diagnostic screening before being referred to specialist evaluations. The article analyzes various instrumental methods of dysphagia assessment, introduces surface electromyography (sEMG) to carry out rapid assessment of such patients, and debates proposed suggestions for sEMG screening protocol in order to identify abnormal deglutition. Data sources Subject related books and articles from 1813 to 2007 were obtained through library search, MEDLINE (1949–2007) and EMBASE (1975–2007). Methods Specifics steps for establishing the protocol for applying the technique for screening purposes (e.g., evaluation of specific muscles), the requirements for diagnostic sEMG equipment, the sEMG technique itself, and defining the tests suitable for assessing deglutition (e.g., saliva, normal, and excessive swallows and uninterrupted drinking of water) are presented in detail. SEMG is compared with other techniques in terms of cost, timing, involvement of radiation, etc. Results According to the published data, SEMG of swallowing is a simple and reliable method for screening and preliminary differentiation among dysphagia and odynophagia of various origins. This noninvasive radiation-free examination has a low level of discomfort, and is simple, time-saving and inexpensive to perform. The major weakness of the method seems to be inability for precise diagnostic of neurologically induced dysphagia. Conclusion With standardization of the technique and an established normative database, sEMG might serve as a reliable screening method for optimal patient management but cannot serve for proper investigation of neurogenic dysphagia. PMID:19232090

  8. Can methylphenidate objectively provide relief in patients with uncontrolled blepharospasm? A pilot study using surface electromyography.

    Science.gov (United States)

    Price, Kristina M; Ramey, Nicholas A; Richard, Michael J; Woodward, Donald J; Woodward, Julie A

    2010-01-01

    To determine whether there is an objective benefit to prescribing Ritalin for patients with uncontrolled blepharospasm exists. Seven subjects with benign essential blepharospasm, who were being treated with botulinum toxin injections and Ritalin LA, were recruited for this pilot study. Patients were asked to participate during the period of time when symptoms were beginning to return. Subjects underwent video and surface electromyography (sEMG) monitoring before and 2 hours after the administration of Ritalin. Mean sEMG potential for each eye was compared before and after the administration of Ritalin. Subjects also rated their disability based on a previously developed and reproducible blepharospasm functional disability scale. Functional Disability Scores were compared, and post-Ritalin treatment benefit was determined. The mean voltage of the sEMG was lower in 13 of 14 eyes after the administration of Ritalin. For the right eye, the voltage decreased by 50% (106.4 ± 13.6 mV to 52.7 ± 7.1 mV, p = 0.015), and for the left eye, by 31% (81.9 ± 9.7 mV to 56.6 ± 6.1 mV, p = 0.031). The Functional Disability Scores were also lower after the administration of Ritalin than before (p = 0.016). A significant decrease in mean voltage after the administration of Ritalin was found in this preselected group of patients. Subjective improvement with decreased disability and increased functional benefit was also found in all subjects. Based on the results of this study, a randomized, controlled study comparing Ritalin versus placebo is needed to determine whether Ritalin should be routinely prescribed for benign essential blepharospasm during the symptomatic window period.

  9. The Eligibility of Surface Electromyography in the Assessment of Paraspinal Muscles Fatigue Following Interventions in Patients with Chronic Low Back Pain: A Systematic Review

    OpenAIRE

    Nahid Rahmani; Mohammad Ali Mohseni-Bandpei; Iraj Abdollahi

    2013-01-01

    Objective: Evaluation of paraspinal muscles endurance in patients with chronic low back pain (LBP) seems to be of great importance. Many studies demonstrated that surface electromyography has merit to assess muscle fatigue using frequency spectrum. The purpose of this study was to systematically review the eligibility of the surface electromyography in the assessment of paraspinal muscles fatigue changes following different interventions in patients with chronic LBP. Materials & Methods: ...

  10. The practical use of surface electromyography during running: does the evidence support the hype? A narrative review.

    Science.gov (United States)

    Subbu, R; Weiler, R; Whyte, G

    2015-01-01

    Surface electromyography (sEMG) is a commonly used technique to investigate muscle activation and fatigue, which is non-invasive and can allow for continuous measurement. Systematic research on the use of sEMG in the sporting environment has been on-going for many years and predominantly based on cycling and rowing activities. To date there have been no reviews assessing the validity and reliability in sEMG exclusively in running activities specifically during on-field testing. The purpose of this review is to evaluate the use of sEMG in the practical context and whether this be translated to on-field testing. Electronic literature searches were performed using the Cochrane Library, PUBMED, CINAHL and PeDro without restrictions on the study date to identify the relevant current English language literature. 10 studies were relevant after title and content review. All the studies identified were all level three evidence based. The general trends of the sEMG activity appear to correlate with running velocity and muscle fatigue seems almost always the consequence of prolonged, dynamic activity. However, these changes are not consistently measured or statistically significant throughout the studies raising the question of the accuracy and reliability when analysing sEMG measurements and making assumptions about the cause of fatigue. An agreed consensus when measuring and analysing sEMG data during running activities particularly in field testing with the most appropriate study design and reliable methodology is yet to be determined and further studies are required.

  11. A Novel Feature Optimization for Wearable Human-Computer Interfaces Using Surface Electromyography Sensors

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    Han Sun

    2018-03-01

    Full Text Available The novel human-computer interface (HCI using bioelectrical signals as input is a valuable tool to improve the lives of people with disabilities. In this paper, surface electromyography (sEMG signals induced by four classes of wrist movements were acquired from four sites on the lower arm with our designed system. Forty-two features were extracted from the time, frequency and time-frequency domains. Optimal channels were determined from single-channel classification performance rank. The optimal-feature selection was according to a modified entropy criteria (EC and Fisher discrimination (FD criteria. The feature selection results were evaluated by four different classifiers, and compared with other conventional feature subsets. In online tests, the wearable system acquired real-time sEMG signals. The selected features and trained classifier model were used to control a telecar through four different paradigms in a designed environment with simple obstacles. Performance was evaluated based on travel time (TT and recognition rate (RR. The results of hardware evaluation verified the feasibility of our acquisition systems, and ensured signal quality. Single-channel analysis results indicated that the channel located on the extensor carpi ulnaris (ECU performed best with mean classification accuracy of 97.45% for all movement’s pairs. Channels placed on ECU and the extensor carpi radialis (ECR were selected according to the accuracy rank. Experimental results showed that the proposed FD method was better than other feature selection methods and single-type features. The combination of FD and random forest (RF performed best in offline analysis, with 96.77% multi-class RR. Online results illustrated that the state-machine paradigm with a 125 ms window had the highest maneuverability and was closest to real-life control. Subjects could accomplish online sessions by three sEMG-based paradigms, with average times of 46.02, 49.06 and 48.08 s

  12. Validity and Reliability of Surface Electromyography Measurements from a Wearable Athlete Performance System

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    Scott K. Lynn, Casey M. Watkins, Megan A. Wong, Katherine Balfany, Daniel F. Feeney

    2018-06-01

    Full Text Available The Athos ® wearable system integrates surface electromyography (sEMG electrodes into the construction of compression athletic apparel. The Athos system reduces the complexity and increases the portability of collecting EMG data and provides processed data to the end user. The objective of the study was to determine the reliability and validity of Athos as compared with a research grade sEMG system. Twelve healthy subjects performed 7 trials on separate days (1 baseline trial and 6 repeated trials. In each trial subjects wore the wearable sEMG system and had a research grade sEMG system’s electrodes placed just distal on the same muscle, as close as possible to the wearable system’s electrodes. The muscles tested were the vastus lateralis (VL, vastus medialis (VM, and biceps femoris (BF. All testing was done on an isokinetic dynamometer. Baseline testing involved performing isometric 1 repetition maximum tests for the knee extensors and flexors and three repetitions of concentric-concentric knee flexion and extension at MVC for each testing speed: 60, 180, and 300 deg/sec. Repeated trials 2-7 each comprised 9 sets where each set included three repetitions of concentric-concentric knee flexion-extension. Each repeated trial (2-7 comprised one set at each speed and percent MVC (50%, 75%, 100% combination. The wearable system and research grade sEMG data were processed using the same methods and aligned in time. The amplitude metrics calculated from the sEMG for each repetition were the peak amplitude, sum of the linear envelope, and 95th percentile. Validity results comprise two main findings. First, there is not a significant effect of system (Athos or research grade system on the repetition amplitude metrics (95%, peak, or sum. Second, the relationship between torque and sEMG is not significantly different between Athos and the research grade system. For reliability testing, the variation across trials and averaged across speeds was 0.8%, 7

  13. Quantitative estimation of muscle fatigue using surface electromyography during static muscle contraction.

    Science.gov (United States)

    Soo, Yewguan; Sugi, Masao; Nishino, Masataka; Yokoi, Hiroshi; Arai, Tamio; Kato, Ryu; Nakamura, Tatsuhiro; Ota, Jun

    2009-01-01

    Muscle fatigue is commonly associated with the musculoskeletal disorder problem. Previously, various techniques were proposed to index the muscle fatigue from electromyography signal. However, quantitative measurement is still difficult to achieve. This study aimed at proposing a method to estimate the degree of muscle fatigue quantitatively. A fatigue model was first constructed using handgrip dynamometer by conducting a series of static contraction tasks. Then the degree muscle fatigue can be estimated from electromyography signal with reasonable accuracy. The error of the estimated muscle fatigue was less than 10% MVC and no significant difference was found between the estimated value and the one measured using force sensor. Although the results were promising, there were still some limitations that need to be overcome in future study.

  14. Non-invasive 3D facial analysis and surface electromyography during functional pre-orthodontic therapy: a preliminary report

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    Gianluca M. Tartaglia

    2009-10-01

    Full Text Available OBJECTIVES: Functional orthodontic devices can modify oral function thus permitting more adequate growth processes. The assessment of their effects should include both facial morphology and muscle function. This preliminary study investigated whether a preformed functional orthodontic device could induce variations in facial morphology and function along with correction of oral dysfunction in a group of orthodontic patients in the mixed and early permanent dentitions. MATERIAL AND METHODS: The three-dimensional coordinates of 50 facial landmarks (forehead, eyes, nose, cheeks, mouth, jaw and ears were collected in 10 orthodontic male patients aged 8-13 years, and in 89 healthy reference boys of the same age. Soft tissue facial angles, distances, and ratios were computed. Surface electromyography of the masseter and temporalis muscles was performed, and standardized symmetry, muscular torque and activity were calculated. Soft-tissue facial modifications were analyzed non-invasively before and after a 6-month treatment with a functional device. Comparisons were made with z-scores and paired Student's t-tests. RESULTS: The 6-month treatment stimulated mandibular growth in the anterior and inferior directions, with significant variations in three-dimensional facial divergence and facial convexity. The modifications were larger in the patients than in reference children. In several occasions, the discrepancies relative to the norm became not significant after treatment. No significant variations in standardized muscular activity were found. CONCLUSIONS: Preliminary results showed that the continuous and correct use of the functional device induced measurable intraoral (dental arches and extraoral (face morphological modifications. The device did not modify the functional equilibrium of the masticatory muscles.

  15. Quadriceps and hamstring muscle activity during cycling as measured with intramuscular electromyography.

    Science.gov (United States)

    da Silva, Julio Cézar Lima; Tarassova, O; Ekblom, M M; Andersson, E; Rönquist, G; Arndt, A

    2016-09-01

    The aim of this study was to describe thigh muscle activation during cycling using intramuscular electromyographic recordings of eight thigh muscles, including the biceps femoris short head (BFS) and the vastus intermedius (Vint). Nine experienced cyclists performed an incremental test (start at 170 W and increased by 20 W every 2 min) on a bicycle ergometer either for a maximum of 20 min or to fatigue. Intramuscular electromyography (EMG) of eight muscles and kinematic data of the right lower limb were recorded during the last 20 s in the second workload (190 W). EMG data were normalized to the peak activity occurring during this workload. Statistical significance was assumed at p ≤ 0.05. The vastii showed a greater activation during the 1st quadrant compared to other quadrants. The rectus femoris (RF) showed a similar activation, but with two bursts in the 1st and 4th quadrants in three subjects. This behavior may be explained by the bi-articular function during the cycling movement. Both the BFS and Vint were activated longer than, but in synergy with their respective agonistic superficial muscles. Intramuscular EMG was used to verify muscle activation during cycling. The activation pattern of deep muscles (Vint and BFS) could, therefore, be described and compared to that of the more superficial muscles. The complex coordination of quadriceps and hamstring muscles during cycling was described in detail.

  16. Surface Electromyography Assessments of the Vastus medialis and Rectus femoris Muscles and Creatine Kinase after Eccentric Contraction Following Glutamine Supplementation.

    Science.gov (United States)

    Rahmani-Nia, Farhad; Farzaneh, Esmail; Damirchi, Arsalan; Majlan, Ali Shamsi; Tadibi, Vahid

    2014-03-01

    L-glutamine is the most abundant amino acid found in human muscle and plays an important role in protein synthesis and can reduce the levels of inflammation biomarkers and creatine kinase (CK) after training sessions. Delayed onset muscle soreness (DOMS) develops after intense exercise and is associated with an inflammatory response. The purpose of this study was to investigate the effect of glutamine supplementation on surface electromyography activity of the vastus medialis muscle (VMM) and rectus femoris muscle (RFM) and levels of creatine kinase after an eccentric contraction. SEVENTEEN HEALTHY MEN (AGE: 22.35±2.27yr; body mass: 69.91± 9.78kg; height: 177.08±4.32cm) were randomly assigned to experimental (n=9) and control groups (n=8) in a double-blind manner. In both groups, subjects were given L-glutamine supplementation (0.1g.kg(-1)) or placebo three times a week for 4 weeks. Median frequency (MDF) and mean power frequency (MPF) for VMM and RFM muscles and also CK measurements were performed before, 24h and 48 h after a resistance training session. The resistance training included 6 sets of eccentric leg extensions to exhaustion with 75% of 1RM. There was no significant difference between groups for MDF or MPF in VMM and RFM. The difference of CK level between the groups was also not significant. The results of this study indicate that glutamine supplementation has no positive effect on muscle injury markers after a resistance training session.

  17. The application of surface electromyography in the assessment of ergonomic risk factors associated with manual lifting tasks.

    Science.gov (United States)

    Chen, Jing; Lei, Yang; Ding, Jiasun; Wang, Zhenglun

    2004-01-01

    The purpose of this study was to evaluate the ergonomic risk factors associated with manual lifting tasks using surface electromyography (EMG). 13 volunteers lifted loads of 6 and 13 kg at two speeds and at two horizontal distances in 3 different postures and three boxes of different sizes, from floor to knuckle height, performing 72 lifting tasks. For each lift, the surface electromyography signals from the erector spinae muscles, bilaterally at T10 and L3, was recorded. The ergonomic risk factors associated with manual lifting tasks were evaluated by comparing the average amplitude of EMG signals from the erector spinae muscles. The EMG average amplitude for lifting the load of 13 kg was 14.3% greater than that for lifting the load of 6 kg (t=-10.93, Pbox, horizontal distance, posture of lifting, the site of the spine subjected to force, lifting speed were the factors affecting the EMG average amplitude. The most significant factor was the loads of lifting, followed by the site of the spine subjected to force and the lifting speed in terms of risk. The ergonomic risk factors associated with manual lifting tasks includes the loads, posture, lifting speed, horizontal distance, the site of the spine subjected to force etc. The results of signal amplitude of EMG from the erector spinae muscles showed that semi-squat posture is the best posture for lifting tasks.

  18. A Novel Phonology- and Radical-Coded Chinese Sign Language Recognition Framework Using Accelerometer and Surface Electromyography Sensors.

    Science.gov (United States)

    Cheng, Juan; Chen, Xun; Liu, Aiping; Peng, Hu

    2015-09-15

    Sign language recognition (SLR) is an important communication tool between the deaf and the external world. It is highly necessary to develop a worldwide continuous and large-vocabulary-scale SLR system for practical usage. In this paper, we propose a novel phonology- and radical-coded Chinese SLR framework to demonstrate the feasibility of continuous SLR using accelerometer (ACC) and surface electromyography (sEMG) sensors. The continuous Chinese characters, consisting of coded sign gestures, are first segmented into active segments using EMG signals by means of moving average algorithm. Then, features of each component are extracted from both ACC and sEMG signals of active segments (i.e., palm orientation represented by the mean and variance of ACC signals, hand movement represented by the fixed-point ACC sequence, and hand shape represented by both the mean absolute value (MAV) and autoregressive model coefficients (ARs)). Afterwards, palm orientation is first classified, distinguishing "Palm Downward" sign gestures from "Palm Inward" ones. Only the "Palm Inward" gestures are sent for further hand movement and hand shape recognition by dynamic time warping (DTW) algorithm and hidden Markov models (HMM) respectively. Finally, component recognition results are integrated to identify one certain coded gesture. Experimental results demonstrate that the proposed SLR framework with a vocabulary scale of 223 characters can achieve an averaged recognition accuracy of 96.01% ± 0.83% for coded gesture recognition tasks and 92.73% ± 1.47% for character recognition tasks. Besides, it demonstrats that sEMG signals are rather consistent for a given hand shape independent of hand movements. Hence, the number of training samples will not be significantly increased when the vocabulary scale increases, since not only the number of the completely new proposed coded gestures is constant and limited, but also the transition movement which connects successive signs needs no

  19. Detection of surface electromyography recording time interval without muscle fatigue effect for biceps brachii muscle during maximum voluntary contraction.

    Science.gov (United States)

    Soylu, Abdullah Ruhi; Arpinar-Avsar, Pinar

    2010-08-01

    The effects of fatigue on maximum voluntary contraction (MVC) parameters were examined by using force and surface electromyography (sEMG) signals of the biceps brachii muscles (BBM) of 12 subjects. The purpose of the study was to find the sEMG time interval of the MVC recordings which is not affected by the muscle fatigue. At least 10s of force and sEMG signals of BBM were recorded simultaneously during MVC. The subjects reached the maximum force level within 2s by slightly increasing the force, and then contracted the BBM maximally. The time index of each sEMG and force signal were labeled with respect to the time index of the maximum force (i.e. after the time normalization, each sEMG or force signal's 0s time index corresponds to maximum force point). Then, the first 8s of sEMG and force signals were divided into 0.5s intervals. Mean force, median frequency (MF) and integrated EMG (iEMG) values were calculated for each interval. Amplitude normalization was performed by dividing the force signals to their mean values of 0s time intervals (i.e. -0.25 to 0.25s). A similar amplitude normalization procedure was repeated for the iEMG and MF signals. Statistical analysis (Friedman test with Dunn's post hoc test) was performed on the time and amplitude normalized signals (MF, iEMG). Although the ANOVA results did not give statistically significant information about the onset of the muscle fatigue, linear regression (mean force vs. time) showed a decreasing slope (Pearson-r=0.9462, pfatigue starts after the 0s time interval as the muscles cannot attain their peak force levels. This implies that the most reliable interval for MVC calculation which is not affected by the muscle fatigue is from the onset of the EMG activity to the peak force time. Mean, SD, and range of this interval (excluding 2s gradual increase time) for 12 subjects were 2353, 1258ms and 536-4186ms, respectively. Exceeding this interval introduces estimation errors in the maximum amplitude calculations

  20. Relationship between ultrasonography and electromyography measurement of abdominal muscles when activated with and without pelvis floor muscles contraction.

    Science.gov (United States)

    Tahan, N; Arab, A M; Arzani, P; Rahimi, F

    2013-12-01

    The importance of the abdominal musculature in spine stability, has promoted the development of a variety of studies. Ultrasound imaging (UI) is a valuable tool which, when applied appropriately, has the potential to provide significant insight into abdominal muscle contraction. Limited studies have been taken place regarding the relationship between ultrasound measures of muscle thickening and electromyography (EMG) measures of activation. Inconsistent results, however, have been reported. Based on previous studies association between abdominal muscle activation and thickening may be affected by contraction level. The aims of this study were to measure the relationship between abdominal muscle thickness and abdominal muscles amplitude in different levels of abdominal muscles contraction. The research was carried on with a convenience sampling at the Physical Therapy Department of University of Social Welfare and Rehabilitation Sciences. Thirty healthy participants volunteered for this study. Muscle thickness right transversus abdominis (TrA) and obliqus internus (OI) muscles in abdominal hallowing maneuvers with and without pelvic floor muscle (PFM) contraction has been measured. Additionally, surface EMG of the right TrA/IO muscles was recorded. A hardware electrical part that acts as trigger system was used to record the activities of abdominal muscles in UI and EMG synchronously. Thickness change, normalized thickness and maximum amplitude abdominal muscles were used for statistical analysis. Correlations between the thickness change and amplitude measures were -0.03 -- 0.38 for TrA/IO. The Correlations between the normalized thickness and amplitude measures were -0.04--0.26 for TrA/IO. There is not clear relationship between increases in abdominal muscle activation and corresponding measures of thickening during abdominal muscle contraction. Changes in thickness of deep abdominal muscle cannot be used to indicate changes in the electrical activity in this

  1. A Longitudinal Electromyography Study of Complex Movements in Poststroke Therapy. 2: Changes in Coordinated Muscle Activation

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    Negin Hesam-Shariati

    2017-07-01

    Full Text Available Fine motor control is achieved through the coordinated activation of groups of muscles, or “muscle synergies.” Muscle synergies change after stroke as a consequence of the motor deficit. We investigated the pattern and longitudinal changes in upper limb muscle synergies during therapy in a largely unconstrained movement in patients with a broad spectrum of poststroke residual voluntary motor capacity. Electromyography (EMG was recorded using wireless telemetry from 6 muscles acting on the more-affected upper body in 24 stroke patients at early and late therapy during formal Wii-based Movement Therapy (WMT sessions, and in a subset of 13 patients at 6-month follow-up. Patients were classified with low, moderate, or high motor-function. The Wii-baseball swing was analyzed using a non-negative matrix factorization (NMF algorithm to extract muscle synergies from EMG recordings based on the temporal activation of each synergy and the contribution of each muscle to a synergy. Motor-function was clinically assessed immediately pre- and post-therapy and at 6-month follow-up using the Wolf Motor Function Test, upper limb motor Fugl-Meyer Assessment, and Motor Activity Log Quality of Movement scale. Clinical assessments and game performance demonstrated improved motor-function for all patients at post-therapy (p < 0.01, and these improvements were sustained at 6-month follow-up (p > 0.05. NMF analysis revealed fewer muscle synergies (mean ± SE for patients with low motor-function (3.38 ± 0.2 than those with high motor-function (4.00 ± 0.3 at early therapy (p = 0.036 with an association trend between the number of synergies and the level of motor-function. By late therapy, there was no significant change between groups, although there was a pattern of increase for those with low motor-function over time. The variability accounted for demonstrated differences with motor-function level (p < 0.05 but not time. Cluster

  2. Continuous Wavelet Transform Analysis of Surface Electromyography for Muscle Fatigue Assessment on the Elbow Joint Motion

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    Triwiyanto Triwiyanto

    2017-01-01

    Full Text Available Studying muscle fatigue plays an important role in preventing the risks associated with musculoskeletal disorders. The effect of elbow-joint angle on time-frequency parameters during a repetitive motion provides valuable information in finding the most accurate position of the angle causing muscle fatigue. Therefore, the purpose of this study is to analyze the effect of muscle fatigue on the spectral and time-frequency domain parameters derived from electromyography (EMG signals using the Continuous Wavelet Transform (CWT. Four male participants were recruited to perform a repetitive motion (flexion and extension movements from a non-fatigue to fatigue condition. EMG signals were recorded from the biceps muscle. The recorded EMG signals were then analyzed offline using the complex Morlet wavelet. The time-frequency domain data were analyzed using the time-averaged wavelet spectrum (TAWS and the Scale-Average Wavelet Power (SAWP parameters. The spectral domain data were analyzed using the Instantaneous Mean Frequency (IMNF and the Instantaneous Mean Power Spectrum (IMNP parameters. The index of muscle fatigue was observed by calculating the increase of the IMNP and the decrease of the IMNF parameters. After performing a repetitive motion from non-fatigue to fatigue condition, the average of the IMNF value decreased by 15.69% and the average of the IMNP values increased by 84%, respectively. This study suggests that the reliable frequency band to detect muscle fatigue is 31.10-36.19Hz with linear regression parameters of 0.979mV^2Hz^(-1 and 0.0095mV^2Hz^(-1 for R^2 and slope, respectively.

  3. Multiparameter Electromyography Analysis of the Masticatory Muscle Activities in Patients with Brainstem Stroke at Different Head Positions

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    Chuyao Jian

    2017-05-01

    Full Text Available The performance of the masticatory muscle is frequently affected and presents high heterogeneity poststroke. Surface electromyography (EMG is widely used to quantify muscle movement patterns. However, only a few studies applied EMG analysis on the research of masticatory muscle activities poststroke, and most of which used single parameter—root mean squares (RMS. The aim of this study was to fully investigate the performance of masticatory muscle at different head positions in healthy subjects and brainstem stroke patients with multiparameter EMG analysis. In this study, 15 healthy subjects and six brainstem stroke patients were recruited to conduct maximum voluntary clenching at five different head positions: upright position, left rotation, right rotation, dorsal flexion, and ventral flexion. The EMG signals of bilateral temporalis anterior and masseter muscles were recorded, and parameters including RMS, median frequency, and fuzzy approximate entropy of the EMG signals were calculated. Two-way analysis of variance (ANOVA with repeated measures and Bonferroni post hoc test were used to evaluate the effects of muscle and head position on EMG parameters in the healthy group, and the non-parametric Wilcoxon signed rank test was conducted in the patient group. The Welch–Satterthwaite t-test was used to compare the between-subject difference. We found a significant effect of subject and muscles but no significant effect of head positions, and the masticatory muscles of patients after brainstem stroke performed significantly different from healthy subjects. Multiparameter EMG analysis might be an informative tool to investigate the neural activity related movement patterns of the deficient masticatory muscles poststroke.

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

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    E Bassani

    2008-02-01

    Full Text Available OBJETIVO: O objetivo desse estudo foi verificar o potencial da eletromiografia (EMG de superfície para a avaliação da eficiência neuromuscular e da fadiga muscular localizada dos extensores lombares em indivíduos com escoliose. MÉTODOS: Participaram deste estudo 20 indivíduos divididos igualmente em dois grupos, (1 Grupo com Escoliose e (2 Grupo Controle, que foram submetidos a um teste de indução dos músculos extensores lombares a fadiga, o qual constituiu da realização de uma contração voluntária máxima isométrica (CVM, e realização de um teste com esforço a 80% da CVM. Foram coletados simultaneamente sinais de força e eletromiográficos (sinal EMG. O sinal EMG foi processado no domínio da freqüência, utilizando-se a transformada rápida de Fourier (FFT, por meio da mediana da freqüência (MF, e no domínio do tempo, pelo cálculo do valor root mean square (RMS. Os dados foram submetidos a uma análise de variância one-way para verificar as diferenças entre os dois grupos. Para verificar a simetria entre os lados direito e esquerdo, foi realizado o teste t pareado. O nível de significância adotado foi 0,05. RESULTADOS: os resultados demonstraram que indivíduos com escoliose apresentaram: (1 simetria de ativação neuromuscular entre os lados; (2 menor eficiência neuromuscular; (3 maior capacidade de resistir a fadiga; e (4 valores de força 42,6% menores que os indivíduos do GC. CONCLUSÕES: Os resultados sugerem que a EMG de superfície corresponde a um efetivo instrumento de avaliação funcional da escoliose, embora o protocolo estabelecido tenha limitado a participação dos indivíduos com escoliose, do ponto de vista da eficiência neuromuscular.OBJECTIVE: The aim of this study was to investigate the potential of surface electromyography (EMG for assessing neuromuscular efficiency and localized muscle fatigue in the lumbar extensors, in individuals with scoliosis. METHODS: Twenty individuals participated

  5. Implementation of a real-time automatic onset time detection for surface electromyography measurement systems using NI myRIO

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    Lersviriyanantakul Chaiwat

    2016-01-01

    Full Text Available For using surface electromyography (sEMG in various applications, the process consists of three parts: an onset time detection for detecting the first point of movement signals, a feature extraction for extracting the signal attribution, and a feature classification for classifying the sEMG signals. The first and the most significant part that influences the accuracy of other parts is the onset time detection, particularly for automatic systems. In this paper, an automatic and simple algorithm for the real-time onset time detection is presented. There are two main processes in the proposed algorithm; a smoothing process for reducing the noise of the measured sEMG signals and an automatic threshold calculation process for determining the onset time. The results from the algorithm analysis demonstrate the performance of the proposed algorithm to detect the sEMG onset time in various smoothing-threshold equations. Our findings reveal that using a simple square integral (SSI as the smoothing-threshold equation with the given sEMG signals gives the best performance for the onset time detection. Additionally, our proposed algorithm is also implemented on a real hardware platform, namely NI myRIO. Using the real-time simulated sEMG data, the experimental results guarantee that the proposed algorithm can properly detect the onset time in the real-time manner.

  6. Surface electromyography assessment of muscle activation patterns while sitting down in young healthy women and patients with ankylosing spondylitis [Povrchové elektromyografické hodnocení svalové aktivity ve zkoušce posazení u zdravých mladých žen a u pacientů s ankylozující spondylitidou

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    Petr Uhlíř

    2011-03-01

    Full Text Available BACKGROUND: Muscle activation patterns depend on many factors. Surface electromyography (SEMG can reveal these patterns in subjects of different ages and health states. We studied patterns of muscle activation in two groups of subjects - healthy young women (as a control group and patients with ankylosing spondylitis. OBJECTIVE: The aim of this study was to register and compare muscle activation patterns while sitting down in these two groups in four situations with different positions of the lower and upper limbs. METHODS: Muscle activity was registered with the use of 8 channel surface polyelectromyography (Noraxon-Myosystem 1400A. We tested the following muscles bilaterally while the subjects were sitting down (tibialis anterior muscle, medial head of the gastrocnemius muscle, gluteus maximus muscle, erectores spinae muscles. The onset of each individual muscle's activity was determined by calculating the sum of the mean value of the SEMG baseline plus 10% of the maximum value of amplitude (peak. RESULTS: It was registered that the medial head of the gastrocnemius muscle and/or erectores spinae muscles were activated as the first ones in both groups of the subjects under study in most of the studied postural situations. We registered differences in timing (sequence of muscle activation among various studied body and limb positions (P–, P+, PD–, and PN–. A great degree of variability in the sequence of muscle activation was revealed, depending on the positions of the upper and lower limbs. CONCLUSIONS: We did not find any unique patterns of muscle activation in either of the two groups under study.[VÝCHODISKA: Časové zapojování (aktivace svalů je závislé na mnoha faktorech. Povrchová polyelektromyografie zachycuje vzorce zapojování svalů u probandů rozdílného věku a zdravotního stavu v různých podmínkách. CÍLE: Cílem studie byla registrace a hodnocení pořadí zapojování svalů v průběhu sedání u t

  7. A surface electromyography based objective method to identify patients with nonspecific chronic low back pain, presenting a flexion related movement control impairment.

    Science.gov (United States)

    Van Damme, Benedicte; Stevens, Veerle; Perneel, Christiaan; Van Tiggelen, Damien; Neyens, Ellen; Duvigneaud, Nathalie; Moerman, Luc; Danneels, Lieven

    2014-12-01

    Movement control impairments (MCI) are often present in patients with non-specific chronic low back pain (NS-CLBP). Therefore, movement control exercises are widely used to rehabilitate patients. However, the objective assessment remains difficult. The purpose of this study was to develop a statistical model, based on logistic regression analysis, to differentiate patients with NS-CLBP presenting a flexion-related MCI from healthy subjects. This model is based on trunk muscle activation patterns measured by surface electromyography (sEMG), during movement control exercises. Sixty-three healthy male subjects and 36 male patients with a flexion-related MCI participated in this study. Muscle activity of the internal obliques, the external obliques, the lumbar multifidus and the thoracic part of the iliocostalis was registered. Ratios of deep stabilizing to superficial torque producing muscle activity were calculated to examine trunk muscle recruitment patterns during 6 different exercises. Logistic regression analyses were performed (1) to define the ratios and exercises that were most discriminating between patients and non-patients, (2) to make a predictive model. K-Fold cross-validation was used to assess the performance of the predictive model. This study demonstrated that sEMG trunk muscle recruitment patterns during movement control tests, allows differentiating NSCLBP patients with a flexion-related MCI from healthy subjects. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Entropic Analysis of Electromyography Time Series

    Science.gov (United States)

    Kaufman, Miron; Sung, Paul

    2005-03-01

    We are in the process of assessing the effectiveness of fractal and entropic measures for the diagnostic of low back pain from surface electromyography (EMG) time series. Surface electromyography (EMG) is used to assess patients with low back pain. In a typical EMG measurement, the voltage is measured every millisecond. We observed back muscle fatiguing during one minute, which results in a time series with 60,000 entries. We characterize the complexity of time series by computing the Shannon entropy time dependence. The analysis of the time series from different relevant muscles from healthy and low back pain (LBP) individuals provides evidence that the level of variability of back muscle activities is much larger for healthy individuals than for individuals with LBP. In general the time dependence of the entropy shows a crossover from a diffusive regime to a regime characterized by long time correlations (self organization) at about 0.01s.

  9. Experimental pain leads to reorganisation of trapezius electromyography during computer work with active and passive pauses

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2009-01-01

    The aim of this laboratory study was to investigate acute effects of experimental muscle pain on spatial electromyographic (EMG) activity of the trapezius muscle during computer work with active and passive pauses. Twelve healthy male subjects performed four sessions of computer work for 2 min...... in one day, with passive (relax) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 40 s without and with presence of experimental pain. Surface EMG signals were recorded from four parts of the trapezius. The centroid of exposure variation analysis along the time axis...... was lower during computer work with active pauses when compared with passive one in all muscle parts (P

  10. Effects of eccentric exercise on trapezius electromyography during computer work with active and passive pauses

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2009-01-01

    ) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 40s over 2 days, before, immediately and 24h after eccentric exercise. Surface EMG signals were recorded from four parts of the trapezius during computer work. FINDINGS: EMG amplitude during computer work decreased......BACKGROUND: The aim of this laboratory study was to investigate the effects of eccentric exercises on the trapezius muscle spatial electromyographic (EMG) activity during computer work with active and passive pauses. METHODS: Twelve healthy male subjects performed computer work with passive (relax...... immediately after exercise (Pwork with active pauses compared with passive ones (P

  11. Muscle Fatigue in the Three Heads of the Triceps Brachii During a Controlled Forceful Hand Grip Task with Full Elbow Extension Using Surface Electromyography.

    Science.gov (United States)

    Ali, Asraf; Sundaraj, Kenneth; Badlishah Ahmad, R; Ahamed, Nizam Uddin; Islam, Anamul; Sundaraj, Sebastian

    2015-06-27

    The objective of the present study was to investigate the time to fatigue and compare the fatiguing condition among the three heads of the triceps brachii muscle using surface electromyography during an isometric contraction of a controlled forceful hand grip task with full elbow extension. Eighteen healthy subjects concurrently performed a single 90 s isometric contraction of a controlled forceful hand grip task and full elbow extension. Surface electromyographic signals from the lateral, long and medial heads of the triceps brachii muscle were recorded during the task for each subject. The changes in muscle activity among the three heads of triceps brachii were measured by the root mean square values for every 5 s period throughout the total contraction period. The root mean square values were then analysed to determine the fatiguing condition for the heads of triceps brachii muscle. Muscle fatigue in the long, lateral, and medial heads of the triceps brachii started at 40 s, 50 s, and 65 s during the prolonged contraction, respectively. The highest fatiguing rate was observed in the long head (slope = -2.863), followed by the medial head (slope = -2.412) and the lateral head (slope = -1.877) of the triceps brachii muscle. The results of the present study concurs with previous findings that the three heads of the triceps brachii muscle do not work as a single unit, and the fiber type/composition is different among the three heads.

  12. Muscle Fatigue in the Three Heads of the Triceps Brachii During a Controlled Forceful Hand Grip Task with Full Elbow Extension Using Surface Electromyography

    Directory of Open Access Journals (Sweden)

    Ali Md. Asraf

    2015-06-01

    Full Text Available The objective of the present study was to investigate the time to fatigue and compare the fatiguing condition among the three heads of the triceps brachii muscle using surface electromyography during an isometric contraction of a controlled forceful hand grip task with full elbow extension. Eighteen healthy subjects concurrently performed a single 90 s isometric contraction of a controlled forceful hand grip task and full elbow extension. Surface electromyographic signals from the lateral, long and medial heads of the triceps brachii muscle were recorded during the task for each subject. The changes in muscle activity among the three heads of triceps brachii were measured by the root mean square values for every 5 s period throughout the total contraction period. The root mean square values were then analysed to determine the fatiguing condition for the heads of triceps brachii muscle. Muscle fatigue in the long, lateral, and medial heads of the triceps brachii started at 40 s, 50 s, and 65 s during the prolonged contraction, respectively. The highest fatiguing rate was observed in the long head (slope = −2.863, followed by the medial head (slope = −2.412 and the lateral head (slope = −1.877 of the triceps brachii muscle. The results of the present study concurs with previous findings that the three heads of the triceps brachii muscle do not work as a single unit, and the fiber type/composition is different among the three heads.

  13. Proceedings of the first workshop on Peripheral Machine Interfaces: going beyond traditional surface electromyography

    Science.gov (United States)

    Castellini, Claudio; Artemiadis, Panagiotis; Wininger, Michael; Ajoudani, Arash; Alimusaj, Merkur; Bicchi, Antonio; Caputo, Barbara; Craelius, William; Dosen, Strahinja; Englehart, Kevin; Farina, Dario; Gijsberts, Arjan; Godfrey, Sasha B.; Hargrove, Levi; Ison, Mark; Kuiken, Todd; Marković, Marko; Pilarski, Patrick M.; Rupp, Rüdiger; Scheme, Erik

    2014-01-01

    One of the hottest topics in rehabilitation robotics is that of proper control of prosthetic devices. Despite decades of research, the state of the art is dramatically behind the expectations. To shed light on this issue, in June, 2013 the first international workshop on Present and future of non-invasive peripheral nervous system (PNS)–Machine Interfaces (MI; PMI) was convened, hosted by the International Conference on Rehabilitation Robotics. The keyword PMI has been selected to denote human–machine interfaces targeted at the limb-deficient, mainly upper-limb amputees, dealing with signals gathered from the PNS in a non-invasive way, that is, from the surface of the residuum. The workshop was intended to provide an overview of the state of the art and future perspectives of such interfaces; this paper represents is a collection of opinions expressed by each and every researcher/group involved in it. PMID:25177292

  14. Proceedings of the first workshop on Peripheral Machine Interfaces: Going beyond traditional surface electromyography

    Directory of Open Access Journals (Sweden)

    Claudio eCastellini

    2014-08-01

    Full Text Available One of the hottest topics in rehabilitation robotics is that of proper control of prosthetic devices. Despite decades of research, the state of the art is dramatically behind the expectations. To shed light on this issue, in June, 2013 the first international workshop on Present and future of non-invasive PNS-Machine Interfaces was convened, hosted by the International Conference on Rehabilitation Robotics. The keyword PNS-Machine Interface (PMI has been selected to denote human-machine interfaces targeted at the limb-deficient, mainly upper-limb amputees, dealing with signals gathered from the peripheral nervous system (PNS in a non-invasive way, that is, from the surface of the residuum. The workshop was intended to provide an overview of the state of the art and future perspectives of such interfaces; this paper represents is a collection of opinions expressed by each and every researcher/group involved in it.

  15. Measurement of muscle length-related electromyography activity of the hip flexor muscles to determine individual muscle contributions to the hip flexion torque.

    Science.gov (United States)

    Jiroumaru, Takumi; Kurihara, Toshiyuki; Isaka, Tadao

    2014-01-01

    This study aimed to investigate muscle length-related electromyography (EMG) of the iliopsoas (IL) and other hip flexor muscles to determine individual muscle contributions to the hip flexion torque. Ten healthy sedentary young men participated in the EMG experiment. A subgroup of six subjects underwent a magnetic resonance imaging (MRI) measurement to confirm the region of the skin over the IL. Surface EMG signals were sampled from the IL, rectus femoris (RF), sartorius (SA), and tensor fasciae latae (TFL) using an active electrode. The subjects performed maximum voluntary isometric hip flexion with the right hip joint set at -10°, 0°, 30°, and 60°. The root mean square (RMS) value for the TFL at 30° (0.81 ± 0.19, p muscle length changes were significantly correlated in the IL (r =0.39, p muscles.

  16. Application of advanced biomechanical methods in studying low back pain – recent development in estimation of lower back loads and large-array surface electromyography and findings

    Directory of Open Access Journals (Sweden)

    Bazrgari B

    2017-07-01

    Full Text Available Babak Bazrgari,1 Ting Xia2 1F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, Lexington, KY, 2Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, IA, USA Abstract: Low back pain (LBP is a major public health problem and the leading disabling musculoskeletal disorder globally. A number of biomechanical methods using kinematic, kinetic and/or neuromuscular approaches have been used to study LBP. In this narrative review, we report recent developments in two biomechanical methods: estimation of lower back loads and large-array surface electromyography (LA-SEMG and the findings associated with LBP. The ability to estimate lower back loads is very important for the prevention and the management of work-related low back injuries based on the mechanical loading model as one category of LBP classification. The methods used for estimation of lower back loads vary from simple rigid link-segment models to sophisticated, optimization-based finite element models. In general, reviewed reports of differences in mechanical loads experienced in lower back tissues between patients with LBP and asymptomatic individuals are not consistent. Such lack of consistency is primarily due to differences in activities under which lower back mechanical loads were investigated as well as heterogeneity of patient populations. The ability to examine trunk neuromuscular behavior is particularly relevant to the motor control model, another category of LBP classification. LA-SEMG not only is noninvasive but also provides spatial resolution within and across muscle groups. Studies using LA-SEMG showed that healthy individuals exhibit highly organized, symmetric back muscle activity patterns, suggesting an orderly recruitment of muscle fibers. In contrast, back muscle activity patterns in LBP patients are asymmetric or multifocal, suggesting lack of orderly muscle recruitment. LA-SEMG was also shown capable of

  17. Spontaneous activity in electromyography may differentiate certain benign lower motor neuron disease forms from amyotrophic lateral sclerosis.

    Science.gov (United States)

    Jokela, Manu E; Jääskeläinen, Satu K; Sandell, Satu; Palmio, Johanna; Penttilä, Sini; Saukkonen, Annamaija; Soikkeli, Raija; Udd, Bjarne

    2015-08-15

    There is limited data on electromyography (EMG) findings in other motor neuron disorders than amyotrophic lateral sclerosis (ALS). We assessed whether the distribution of active denervation detected by EMG, i.e. fibrillations and fasciculations, differs between ALS and slowly progressive motor neuron disorders. We compared the initial EMG findings of 43 clinically confirmed, consecutive ALS patients with those of 41 genetically confirmed Late-onset Spinal Motor Neuronopathy and 14 Spinal and Bulbar Muscular Atrophy patients. Spontaneous activity was more frequently detected in the first dorsal interosseus and deltoid muscles of ALS patients than in patients with the slowly progressive motor neuron diseases. The most important observation was that absent fibrillations in the first dorsal interosseus muscle identified the benign forms with sensitivities of 66%-77% and a specificity of 93%. The distribution of active denervation may help to separate ALS from mimicking disorders at an early stage. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Surface electromyography based muscle fatigue detection using high-resolution time-frequency methods and machine learning algorithms.

    Science.gov (United States)

    Karthick, P A; Ghosh, Diptasree Maitra; Ramakrishnan, S

    2018-02-01

    Surface electromyography (sEMG) based muscle fatigue research is widely preferred in sports science and occupational/rehabilitation studies due to its noninvasiveness. However, these signals are complex, multicomponent and highly nonstationary with large inter-subject variations, particularly during dynamic contractions. Hence, time-frequency based machine learning methodologies can improve the design of automated system for these signals. In this work, the analysis based on high-resolution time-frequency methods, namely, Stockwell transform (S-transform), B-distribution (BD) and extended modified B-distribution (EMBD) are proposed to differentiate the dynamic muscle nonfatigue and fatigue conditions. The nonfatigue and fatigue segments of sEMG signals recorded from the biceps brachii of 52 healthy volunteers are preprocessed and subjected to S-transform, BD and EMBD. Twelve features are extracted from each method and prominent features are selected using genetic algorithm (GA) and binary particle swarm optimization (BPSO). Five machine learning algorithms, namely, naïve Bayes, support vector machine (SVM) of polynomial and radial basis kernel, random forest and rotation forests are used for the classification. The results show that all the proposed time-frequency distributions (TFDs) are able to show the nonstationary variations of sEMG signals. Most of the features exhibit statistically significant difference in the muscle fatigue and nonfatigue conditions. The maximum number of features (66%) is reduced by GA and BPSO for EMBD and BD-TFD respectively. The combination of EMBD- polynomial kernel based SVM is found to be most accurate (91% accuracy) in classifying the conditions with the features selected using GA. The proposed methods are found to be capable of handling the nonstationary and multicomponent variations of sEMG signals recorded in dynamic fatiguing contractions. Particularly, the combination of EMBD- polynomial kernel based SVM could be used to

  19. Evaluating the Training Effects of Two Swallowing Rehabilitation Therapies Using Surface Electromyography--Chin Tuck Against Resistance (CTAR) Exercise and the Shaker Exercise.

    Science.gov (United States)

    Sze, Wei Ping; Yoon, Wai Lam; Escoffier, Nicolas; Rickard Liow, Susan J

    2016-04-01

    In this study, the efficacy of two dysphagia interventions, the Chin Tuck against Resistance (CTAR) and Shaker exercises, were evaluated based on two principles in exercise science-muscle-specificity and training intensity. Both exercises were developed to strengthen the suprahyoid muscles, whose contractions facilitate the opening of the upper esophageal sphincter, thereby improving bolus transfer. Thirty-nine healthy adults performed two trials of both exercises in counter-balanced order. Surface electromyography (sEMG) recordings were simultaneously collected from suprahyoid muscle group and sternocleidomastoid muscle during the exercises. Converging results using sEMG amplitude analyses suggested that the CTAR was more specific in targeting the suprahyoid muscles than the Shaker exercise. Fatigue analyses on sEMG signals further indicated that the suprahyoid muscle group were equally or significantly fatigued (depending on metric), when participants carried out CTAR compared to the Shaker exercise. Importantly, unlike during Shaker exercise, the sternocleidomastoid muscles were significantly less activated and fatigued during CTAR. Lowering the chin against resistance is therefore sufficiently specific and intense to fatigue the suprahyoid muscles.

  20. Voluntary low-force contraction elicits prolonged low-frequency fatigue and changes in surface electromyography and mechanomyography

    DEFF Research Database (Denmark)

    Blangsted, Anne Katrine; Sjøgaard, Gisela; Madeleine, Pascal

    2005-01-01

    Controversies exist regarding objective documentation of fatigue development with low-force contractions. We hypothesized that non-exhaustive, low-force muscle contraction may induce prolonged low-frequency fatigue (LFF) that in the subsequent recovery period is detectable by electromyography (EMG...

  1. Analysis of one repetition during biceps curl exercise among age-matched adult volunteers using endurance, curl speed and surface electromyography signals.

    Science.gov (United States)

    Marri, Kiran; Maitra Ghosh, Diptasree; Swaminathan, Ramakrishnan

    2017-07-01

    Exercises under isometric and dynamic contractions are influenced by the rate coding and recruitment strategies. The study of muscle strength under dynamic contraction is normally performed using one-repetition maximum (1-RM) method. There are several variants of deriving one repetition method using number of repetitions and load that are useful in physical fitness and clinical rehabilitation program. However, the factors of dynamic contractions such as endurance time, speed of muscle contractions and muscle activity are not considered in 1-RM methods. The muscular activities are analyzed using surface electromyography (sEMG) signals. Limited work has been reported on the relationship between the 1-RM method and factors such as endurance time, speed of contraction and sEMG activity. In this work, a modified 1-RM method is proposed, namely, N-RM, using load, number of repetitions, endurance time, speed of contraction and normalized sEMG activity. For this purpose, sEMG signals are recorded from 58 healthy subjects under standard dynamic contraction protocol involving curl exercise. Conventional 1-RM is computed by using Epley's method and compared with proposed method using correlation analysis. The results show that 1-RM increases linearly with number of curls (r=1) but has a poor correlation coefficient with sEMG (r=0.01) and endurance time (r =0.4). The curl speed for lower 1-RM and higher 1-RM did not show any statistical difference (p =0.2). The proposed N-RM is observed to have good correlation with endurance time (r=0.734), curl speed (r=0.893) and sEMG activity (r=0.8851). These results demonstrate that the proposed N-RM is highly correlated to factors influencing the dynamic contractions. This method can be further extended to assess muscles under various clinical disorders and sports training.

  2. Piriformis electromyography activity during prone and side-lying hip joint movement.

    Science.gov (United States)

    Morimoto, Yasuhiro; Oshikawa, Tomoki; Imai, Atsushi; Okubo, Yu; Kaneoka, Koji

    2018-01-01

    [Purpose] To measure electromyographic activity of the piriformis using fine-wire electrodes during 7 hip movements. [Subjects and Methods] Eleven healthy men, without severe low back pain or lower limb injury, participated in this study. Fine-wire electrodes were inserted into the piriformis and surface electrodes were attached to the muscles in the hip region and the trunk muscles on the dominant arm side. Electromyographic signal amplitude was measured during 7 hip movements: side-lying external rotation in hip neutral position, side-lying abduction in hip neutral position, side-lying abduction in hip external rotation, side-lying abduction in hip internal rotation, prone extension in hip neutral position, prone extension in hip external rotation, and prone extension in hip internal rotation. Repeated-measures one-way analysis of variance was used to examine electromyographic activity in each of the 7 hip movements. [Results] Piriformis electromyographic activity was highest during prone hip extension in external rotation. Both the superior and inferior portions of the gluteus maximus were also highly activated during prone hip extension in external rotation. [Conclusion] Prone hip extension in external rotation induced high electromyographic activity in the piriformis and superior and inferior gluteus maximus muscles.

  3. Effects of Force Load, Muscle Fatigue, and Magnetic Stimulation on Surface Electromyography during Side Arm Lateral Raise Task: A Preliminary Study with Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Liu Cao

    2017-01-01

    Full Text Available The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue, and extremely low-frequency (ELF magnetic stimulation on surface electromyography (SEMG signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI ActiveTwo system during side lateral raise task (with the right arm 90 degrees away from the body with three different loads on the forearm (0 kg, 1 kg, and 3 kg; their order was randomized between subjects. The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as nonfatigue status and the last 10 s before the subject was exhausted was regarded as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, and this time the ELF magnetic stimulation was applied to the subject’s deltoid muscle during the five-minute rest period. Three commonly used SEMG features, root mean square (RMS, median frequency (MDF, and sample entropy (SampEn, were analyzed and compared between different loads, nonfatigue/fatigue status, and ELF stimulation and no stimulation. Variance analysis results showed that the effect of force load on RMS was significant (p0.05. In comparison with nonfatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p<0.001 and MDF and SampEn were significantly smaller (all p<0.001.

  4. Effects of Force Load, Muscle Fatigue, and Magnetic Stimulation on Surface Electromyography during Side Arm Lateral Raise Task: A Preliminary Study with Healthy Subjects.

    Science.gov (United States)

    Cao, Liu; Wang, Ying; Hao, Dongmei; Rong, Yao; Yang, Lin; Zhang, Song; Zheng, Dingchang

    2017-01-01

    The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue, and extremely low-frequency (ELF) magnetic stimulation on surface electromyography (SEMG) signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI ActiveTwo system during side lateral raise task (with the right arm 90 degrees away from the body) with three different loads on the forearm (0 kg, 1 kg, and 3 kg; their order was randomized between subjects). The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as nonfatigue status and the last 10 s before the subject was exhausted was regarded as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, and this time the ELF magnetic stimulation was applied to the subject's deltoid muscle during the five-minute rest period. Three commonly used SEMG features, root mean square (RMS), median frequency (MDF), and sample entropy (SampEn), were analyzed and compared between different loads, nonfatigue/fatigue status, and ELF stimulation and no stimulation. Variance analysis results showed that the effect of force load on RMS was significant ( p 0.05). In comparison with nonfatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p < 0.001) and MDF and SampEn were significantly smaller (all p < 0.001).

  5. Region-dependent hamstrings activity in Nordic hamstring exercise and stiff-leg deadlift defined with high-density electromyography.

    Science.gov (United States)

    Hegyi, A; Péter, A; Finni, T; Cronin, N J

    2018-03-01

    Recent studies suggest region-specific metabolic activity in hamstring muscles during injury prevention exercises, but the neural representation of this phenomenon is unknown. The aim of this study was to examine whether regional differences are evident in the activity of biceps femoris long head (BFlh) and semitendinosus (ST) muscles during two common injury prevention exercises. Twelve male participants without a history of hamstring injury performed the Nordic hamstring exercise (NHE) and stiff-leg deadlift (SDL) while BFlh and ST activities were recorded with high-density electromyography (HD-EMG). Normalized activity was calculated from the distal, middle, and proximal regions in the eccentric phase of each exercise. In NHE, ST overall activity was substantially higher than in BFlh (d = 1.06 ± 0.45), compared to trivial differences between muscles in SDL (d = 0.19 ± 0.34). Regional differences were found in NHE for both muscles, with different proximal-distal patterns: The distal region showed the lowest activity level in ST (regional differences, d range = 0.55-1.41) but the highest activity level in BFlh (regional differences, d range = 0.38-1.25). In SDL, regional differences were smaller in both muscles (d range = 0.29-0.67 and 0.16-0.63 in ST and BFlh, respectively) than in NHE. The use of HD-EMG in hamstrings revealed heterogeneous hamstrings activity during typical injury prevention exercises. High-density EMG might be useful in future studies to provide a comprehensive overview of hamstring muscle activity in other exercises and high-injury risk tasks. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. [Evaluation of the electromyography activity of pelvic floor muscle during postural exercises using the Wii Fit Plus©. Analysis and perspectives in rehabilitation].

    Science.gov (United States)

    Steenstrup, B; Giralte, F; Bakker, E; Grise, P

    2014-12-01

    The aim of this work was to evaluate the effect of postural awareness by using the Wii Fit Plus© on the quality of the baseline (automatic) activity of the pelvic floor muscles (PFM) measured by intravaginal surface electromyography (sEMG). Four healthy continent female subjects, all able to perform a voluntary contraction, undertook 2 sets of 3 various exercises offered by the software Wii Fit Plus© using the Wii balance board© (WBB): one set without any visual control and the second set with postural control and sEMG visual feedback. Simultaneously, we recorded the sEMG activity of the PFM. Mean baseline activity of PFM in standing position at start was 2.87 mV, at submaximal voluntary contraction the sEMG activity raised at a mean of 14.43 mV (7.87-21.89). In the first set of exercises on the WBB without any visual feedback, the automatic activity of the PFM increased from 2.87 mV to 8.75 mV (7.96-9.59). In the second set, with visual postural and sEMG control, mean baseline sEMG activity even raised at 11.39 mV (10.17-11.58). Among women able of a voluntary contraction of PFM, visualisation of posture with the help of the WBB and of sEMG activity of the PFM during static and dynamic Wii Fit Plus© activities, may improve the automatic activation of the PFMs. 4. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  7. Voluntary low-force contraction elicits prolonged low-frequency fatigue and changes in surface electromyography and mechanomyography

    DEFF Research Database (Denmark)

    Blangsted, Anne Katrine; Sjøgaard, Gisela; Madeleine, Pascal

    2005-01-01

    Controversies exist regarding objective documentation of fatigue development with low-force contractions. We hypothesized that non-exhaustive, low-force muscle contraction may induce prolonged low-frequency fatigue (LFF) that in the subsequent recovery period is detectable by electromyography (EMG......) and in particular mechanomyography (MMG) during low-force rather than high-force test contractions. Seven subjects performed static wrist extension at 10% maximal voluntary contraction (MVC) for 10 min (10%MVC10 min). Wrist force response to electrical stimulation of extensor carpi radialis muscle (ECR) quantified...... LFF. EMG and MMG were recorded from ECR during static test contractions at 5% and 80% MVC. Electrical stimulation, MVC, and test contractions were performed before 10%MVC10 min and at 10, 30, 90 and 150 min recovery. In spite of no changes in MVC, LFF persisted up to 150 min recovery but did...

  8. Inter-day reliability of surface electromyography recordings of the lumbar part of erector spinae longissimus and trapezius descendens during box lifting.

    Science.gov (United States)

    Brandt, Mikkel; Andersen, Lars Louis; Samani, Afshin; Jakobsen, Markus Due; Madeleine, Pascal

    2017-12-11

    Low back pain and neck-shoulder pain are the most reported types of work-related musculoskeletal disorders, and performing heavy lifting at work and working with trunk rotation increase the risk of developing work-related musculoskeletal disorders. Surface electromyography (sEMG) provides information about the electrical activity of muscles. Thus it has the potential to retrieve indirect information about the physical exposure of specific muscles of workers during their actual work. This study aimed to investigate the inter-day reliability of absolute and normalized amplitude of sEMG measurements obtained during repeated standardized reference lifts. The inter-day reliability of sEMG of the erector spinae longissimus and trapezius descendens muscles was tested during standardized box lifts. The lifts were performed with loads of 3, 15 and 30 kg from floor to table and from table to table in three conditions, i.e., forearm length (short reaching distance), ¾ arm length (long reaching distance) and forearm length with trunk rotation. Absolute and normalized root mean square (absRMS and normRMS) values were extracted. In line with the guidelines for reporting reliability and agreement studies, we reported relative and absolute reliability estimated by intra class correlation (ICC 3,K ), standard error of measurement (SEM) and minimal detectable change in percent (MDC). The ICC 3,K was higher for absRMS compared with normRMS while SEM and maximal voluntary contraction (MVC) were similar. A total of 50 out of 56, i.e., 89%, and 41 out of 56, i.e., 73%, of the lifting situations were in the range from moderate to almost perfect for absRMS and normRMS, respectively. The SEM and MDC shoved more variation in the lifting situations performed from floor to table and in the trapezius descendens muscle than in the erector spinae longissimus muscle. This reliability study showed that maximum absRMS and normRMS were found to have a fair to substantial relative inter

  9. Changes in surface electromyography signals and kinetics associated with progression of fatigue at two speeds during wheelchair propulsion.

    Science.gov (United States)

    Qi, Liping; Wakeling, James; Grange, Simon; Ferguson-Pell, Martin

    2012-01-01

    The purpose of this study was to determine whether muscle balance is influenced by fatigue in a recordable way, toward creating novel defensive activity strategies for manual wheelchair users (MWUs). Wheelchair propulsion to a point of mild fatigue, level 15 on the Rating of Perceived Exertion scale, was investigated at two different speeds. Surface electromyographic (EMG) activity of 7 muscles was recorded on 14 nondisabled participants. Kinetic variables were measured using a SmartWheel. No significant effect was found of percentage endurance time on kinetic variables for the two propulsion speeds. Fatigue-related changes in the EMG spectra were identified as an increase of EMG intensity and a decrease of mean power frequency as a function of percent endurance time for the tested muscles under both fast and slow speed conditions. The greater increases in activity for propulsive muscles compared with recovery muscles during fast speed wheelchair propulsion indicated muscle imbalance associated with fatiguing wheelchair propulsion. This study shows how kinetic and EMG information might be used as feedback to MWUs to ensure that they conduct activity in ways that do not precipitate injury.

  10. Tensor veli palatini electromyography for monitoring Eustachian tube rehabilitation in otitis media.

    Science.gov (United States)

    Picciotti, P M; Della Marca, G; D'Alatri, L; Lucidi, D; Rigante, M; Scarano, E

    2017-05-01

    The pathogenesis of otitis media is related to Eustachian tube dysfunction. The tensor veli palatini muscle actively opens the Eustachian tube and promotes middle-ear ventilation. This study describes a technique for paratubal electromyography that uses a surface, non-invasive electrode able to record tensor veli palatini muscle activity during swallowing. Twenty otitis media patients and 10 healthy patients underwent tensor veli palatini electromyography. Activity of this muscle before and after Eustachian tube rehabilitation was also assessed. In 78.5 per cent of patients, the electromyography duration phase and/or amplitude were reduced in the affected side. The muscle action potential was impaired in all patients who underwent Eustachian tube rehabilitation. This study confirmed that Eustachian tube muscle dysfunction has a role in otitis media pathogenesis and showed that muscle activity increases after Eustachian tube rehabilitation therapy.

  11. Eletromiografia de superfície para avaliação dos músculos do assoalho pélvico feminino: revisão de literatura Evaluation of female pelvic floor muscles using surface electromyography: literature review

    Directory of Open Access Journals (Sweden)

    Ana Paula Magalhães Resende

    2011-09-01

    Full Text Available A eletromiografia de superfície tem grande importância clínica e de pesquisa para o fisioterapeuta. Apesar de captar a atividade elétrica promovida pelo recrutamento das unidades motoras, há boa correlação entre o número de unidades ativadas e a força muscular. É um dos métodos de maior especificidade na avaliação do assoalho pélvico, embora não haja consenso em relação à sua aplicação. Essa revisão de literatura foi desenvolvida com o objetivo de agrupar as informações sobre o uso da eletromiografia de superfície na avaliação do assoalho pélvico. Foram pesquisados artigos nas bases de dados Medline, PubMed, Lilacs, SciELO e Biblioteca Cochrane, e selecionados os que avaliassem o assoalho pélvico feminino por meio de eletromiografia de superfície. Apesar de sua metodologia ainda carecer de padronização, é um instrumento que deve ser considerado nas pesquisas científicas em nosso meio, pois parece apresentar boa reprodutibilidade e confiabilidade. Pacientes com disfunções do assoalho pélvico possuem alterações no tempo de ativação dos músculos do assoalho pélvico (MAP e músculos abdominais. Quanto à gestação e puerpério, ainda faltam evidências sobre possíveis alterações da ativação elétrica dos MAP nesses períodos.Surface electromyography has clinical and research importance for the physiotherapist. Although capturing electrical activity promoted by recruitment of motor units, there is a good correlation between the number of activated units and muscle strength. This is one of the methods of higher specificity in pelvic floor evaluation, although the lack of consensus regarding its application. The aim of this literature review was to cluster information regarding to the use of surface electromyography in the evaluation of pelvic floor. Papers were searched in Medline, Pubmed Lilacs, SciELO and Cochrane Library. Were selected papers which methods used surface electromyography to evaluate the

  12. Mechanics of active surfaces

    Science.gov (United States)

    Salbreux, Guillaume; Jülicher, Frank

    2017-09-01

    We derive a fully covariant theory of the mechanics of active surfaces. This theory provides a framework for the study of active biological or chemical processes at surfaces, such as the cell cortex, the mechanics of epithelial tissues, or reconstituted active systems on surfaces. We introduce forces and torques acting on a surface, and derive the associated force balance conditions. We show that surfaces with in-plane rotational symmetry can have broken up-down, chiral, or planar-chiral symmetry. We discuss the rate of entropy production in the surface and write linear constitutive relations that satisfy the Onsager relations. We show that the bending modulus, the spontaneous curvature, and the surface tension of a passive surface are renormalized by active terms. Finally, we identify active terms which are not found in a passive theory and discuss examples of shape instabilities that are related to active processes in the surface.

  13. Combined surface electromyography, near-infrared spectroscopy and acceleration recordings of muscle contraction: The effect of motion

    Directory of Open Access Journals (Sweden)

    Krista Kauppi

    2017-03-01

    This paper reviews the current state of noninvasive EMG and NIRS-based methods used to study muscle function. In addition, we built a combined sEMG/NIRS/ACM sensor to perform simultaneous measurements for static and dynamic exercises of a biceps brachii muscle. Further, we discuss the effect of muscle motion in response of NIRS and EMG when measured noninvasively. Based on our preliminary studies, both NIRS and EMG supply specific information on muscle activation, but their signal responses also showed similarities with acceleration signals which, in this case, were supposed to be solely sensitive to motions.

  14. [A field study on the work load and muscle fatigue at neck-shoulder in female sewing machine operators by using surface electromyography].

    Science.gov (United States)

    Zhang, Fei-ruo; Wang, Sheng; He, Li-hua; Zhang, Ying; Wu, Shan-shan; Li, Jing-yun; Hu, Guang-yi; Ye, Kang-ping

    2011-03-01

    To study neck and shoulder work-related muscle fatigue of female sewing machine operators. 18 health female sewing machine operators without musculoskeletal disorders work in Beijing garment industry factory as volunteers in participate of this study. The maximal voluntary contraction (MVC) and 20% MVC of bilateral upper trapezium and cervical erectors spinae was tested before sewing operations, then the whole 20 time windows (1 time window = 10 min) sewing machine operations was monitored and the surface electromyography (sEMG) signals simultaneously was recorded after monitoring the 20%MVC was tested. Use amplitude analysis method to reduction recorded EMG signals. During work, the median load for the left cervical erector spinae (LCES), right cervical erector spinae (RCES), left upper trapezium (LUT) and right upper trapezium (RUT) respectively was 6.78 ± 1.05, 6.94 ± 1.12, 5.68 ± 2.56 and 6.47 ± 3.22, work load of right is higher than the left; static load analysis indicated the value of RMS(20%MVC) before work was higher than that value after work, the increase of right CES and UT RMS(20%MVC) was more; the largest 20%MVE of bilateral CES occurred at 20th time window, and that of bilateral UT happened at 16th. The work load of female sewing machine operators is sustained "static" load, and work load of right neck-shoulder is higher than left, right neck-shoulder muscle is more fatigable and much serious once fatigued.

  15. Cross-correlation of motor activity signals from dc-magnetoencephalography, near-infrared spectroscopy, and electromyography.

    Science.gov (United States)

    Sander, Tilmann H; Leistner, Stefanie; Wabnitz, Heidrun; Mackert, Bruno-Marcel; Macdonald, Rainer; Trahms, Lutz

    2010-01-01

    Neuronal and vascular responses due to finger movements were synchronously measured using dc-magnetoencephalography (dcMEG) and time-resolved near-infrared spectroscopy (trNIRS). The finger movements were monitored with electromyography (EMG). Cortical responses related to the finger movement sequence were extracted by independent component analysis from both the dcMEG and the trNIRS data. The temporal relations between EMG rate, dcMEG, and trNIRS responses were assessed pairwise using the cross-correlation function (CCF), which does not require epoch averaging. A positive lag on a scale of seconds was found for the maximum of the CCF between dcMEG and trNIRS. A zero lag is observed for the CCF between dcMEG and EMG. Additionally this CCF exhibits oscillations at the frequency of individual finger movements. These findings show that the dcMEG with a bandwidth up to 8 Hz records both slow and faster neuronal responses, whereas the vascular response is confirmed to change on a scale of seconds.

  16. Electromyography characterization of stretch responses in hemiparetic stroke patients and their relationship with the Modified Ashworth scale.

    Science.gov (United States)

    Cooper, A; Musa, I M; van Deursen, R; Wiles, C M

    2005-10-01

    To determine the validity of the Modified Ashworth Scale as a measure of spasticity by determining its relationship to surface electromyography activity and contracture. A controlled study of hemiparetic stroke patients with spasticity. A physiotherapy department in a secondary care hospital. Thirty-one stroke patients and 20 healthy volunteers. The resistance to passive movement around the knee and ankle of the affected and unaffected legs was rated using the Modified Ashworth Scale. Passive range of movement was measured with a goniometer. Surface electromyography recordings of four lower limb muscles were taken during passive stretches of the knee and ankle. Hemiparetic patients produced surface electromyography responses to stretch that were of greater amplitude (unaffected limbs: mean = 25.82 mV (43.85), affected limbs: mean = 24.77 mV (35.46)) than those of healthy volunteers (mean = 15.85 (29.96)). The affected muscles of hemiparetic patients were more likely to produce surface electromyography responses to stretch of a sustained duration (45% of cases) compared with unaffected limbs (24% of cases) and those of healthy volunteers (16% of cases). The Modified Ashworth Scale showed a positive correlation with the magnitude (p Ashworth Scale were associated with contracture (p Ashworth Scale reflects spasticity in terms of surface electromyography stretch responses produced by passive movement, but the relationship of spasticity to contracture remains unclear.

  17. Embroidered Electromyography: A Systematic Design Guide.

    Science.gov (United States)

    Shafti, Ali; Ribas Manero, Roger B; Borg, Amanda M; Althoefer, Kaspar; Howard, Matthew J

    2017-09-01

    Muscle activity monitoring or electromyography (EMG) is a useful tool. However, EMG is typically invasive, expensive and difficult to use for untrained users. A possible solution is textile-based surface EMG (sEMG) integrated into clothing as a wearable device. This is, however, challenging due to 1) uncertainties in the electrical properties of conductive threads used for electrodes, 2) imprecise fabrication technologies (e.g., embroidery, sewing), and 3) lack of standardization in design variable selection. This paper, for the first time, provides a design guide for such sensors by performing a thorough examination of the effect of design variables on sEMG signal quality. Results show that imprecisions in digital embroidery lead to a trade-off between low electrode impedance and high manufacturing consistency. An optimum set of variables for this trade-off is identified and tested with sEMG during a variable force isometric grip exercise with n = 12 participants, compared with conventional gel-based electrodes. Results show that thread-based electrodes provide a similar level of sensitivity to force variation as gel-based electrodes with about 90% correlation to expected linear behavior. As proof of concept, jogging leggings with integrated embroidered sEMG are made and successfully tested for detection of muscle fatigue while running on different surfaces.

  18. Classifying Apnea of Prematurity by Transcutaneous Electromyography of the Diaphragm

    NARCIS (Netherlands)

    Kraaijenga, Juliette V.; Hutten, Gerard J.; de Waal, Cornelia G.; de Jongh, Frans H.; Onland, Wes; van Kaam, Anton H.

    2018-01-01

    Background: Treatment of apnea is highly dependent on the type of apnea. Chest impedance (CI) has inaccuracies in monitoring respiration, which compromises accurate apnea classification. Electrical activity of the diaphragm measured by transcutaneous electromyography (EMG) is feasible in preterm

  19. Amphoteric surface active agents

    OpenAIRE

    Eissa, A.M. F.

    1995-01-01

    2-[trimethyl ammonium, triethyl ammonium, pyridinium and 2-amino pyridinium] alkanoates, four series of surface active agents containing carbon chain C12, C14, C16 and C18carbon atoms, were prepared. Their structures were characterized by microanalysis, infrared (IR) and nuclear magnetic resonance (NMR). Surface and interfacial tension, Krafft point, wetting time, emulsification power, foaming height a...

  20. Changes in Muscle Activation Following Ankle Strength Training in Children with Spastic Cerebral Palsy: An Electromyography Feasibility Case Report

    Science.gov (United States)

    Olsen, Jamie E.; Ross, Sandy A.; Foreman, Matthew H.; Engsberg, Jack R.

    2013-01-01

    Children with cerebral palsy (CP) are likely to experience decreased participation in activities and less competence in activities of daily living. Studies of children with spastic CP have shown that strengthening programs produce positive results in strength, gait, and functional outcomes (measured by the Gross Motor Function Measure). No…

  1. Effects of performing an abdominal hollowing exercise on trunk muscle activity during curl-up exercise on an unstable surface

    OpenAIRE

    Kim, Moon-Hwan; Oh, Jae-Seop

    2015-01-01

    [Purpose] The purpose of this study was to investigate the effects of the abdominal hollowing exercise on trunk muscle activity during the curl-up exercise on an unstable surface by measuring electromyography (EMG) activity. [Subjects] Fourteen young healthy adults (nine male, five female) voluntarily participated in this study. [Methods] Each subject was asked to perform a curl-up exercise on two supporting surfaces (stable and unstable surfaces) combined with the abdominal hollowing exercis...

  2. Eletromiografia de superfície no diagnóstico da dominância lateral em crianças: aspectos psicomotores Surface electromyography in diagnosis of lateral dominance in children: psychomotor aspects

    Directory of Open Access Journals (Sweden)

    Ceme Ferreira Jordy

    1995-09-01

    Full Text Available A dominância lateral foi verificada pelo eletromiograma de superfície em 100 crianças neurologicamente normais. Foram usados estímulos verbais durante os registros eletromiográficos. Em comparação com o diagnóstico clínico, a eletromiografia se revelou mais precisa, excluindo influências subjetivas nos resultados. Destrismo foi diagnosticado em 90 pacientes, canhotismo em 3 e dominância indefinida em 7. Mecanismos de ordem psicomotora são sugeridos para justificar as respostas motoras provocadas por estímulos verbais com conteúdo afetivo.Surface electromyography was used to verify the lateral dominance in 100 six to fourteen years old normal children. Electromyographic records were obtained during verbal stimulation. Dexterity was found in 90, sinistrality in 3 and indefinite dominance in 7 patients. Comparing with results from clinical examination, the electromyography seems more accurate and easy to perform. The responses obtained after verbal stimulations were attributed to a psychomotor phenomenon. Mechanisms involved in the production of muscle contractions after verbal stimulation, were not proved. Pharmacologic action of cathecolamines on the central motor neural subsystems is advanced.

  3. Amphoteric surface active agents

    Directory of Open Access Journals (Sweden)

    Eissa, A.M. F.

    1995-10-01

    Full Text Available 2-[trimethyl ammonium, triethyl ammonium, pyridinium and 2-amino pyridinium] alkanoates, four series of surface active agents containing carbon chain C12, C14, C16 and C18carbon atoms, were prepared. Their structures were characterized by microanalysis, infrared (IR and nuclear magnetic resonance (NMR. Surface and interfacial tension, Krafft point, wetting time, emulsification power, foaming height and critical micelle concentration (cmc were determined and a comparative study was made between their chemical structure and surface active properties. Antimicrobial activity of these surfactants was also determined.

    Se prepararon cuatro series de agentes tensioactivos del tipo 2-[trimetil amonio, trietil amonio, piridinio y 2-amino piridinio] alcanoatos, que contienen cadenas carbonadas con C12, C14, C16 y C18 átomos de carbono.
    Se determinaron la tensión superficial e interfacial, el punto de Krafft, el tiempo humectante, el poder de emulsionamiento, la altura espumante y la concentración critica de miscela (cmc y se hizo un estudio comparativo entre la estructura química y sus propiedades tensioactivas. Se determinó también la actividad antimicrobiana de estos tensioactivos. Estas estructuras se caracterizaron por microanálisis, infrarrojo (IR y resonancia magnética nuclear (RMN.

  4. Hip strategy alterations in patients with history of low disc herniation and non-specific low back pain measured by surface electromyography and balance platform.

    Science.gov (United States)

    Ciesielska, Jagoda; Lisiński, Przemysław; Bandosz, Agata; Huber, Juliusz; Kulczyk, Aleksandra; Lipiec, Joanna

    2015-01-01

    The appearance of pathology in the lumbar spine, such as a previous episode of low disc herniation or non-specific low back pain contributes to improper activation of the hip muscles. The aim of the study was to detect alterations in hip strategy manifested by differences in balance parameters and rectus femoris and gluteus maximus activity in people with previous episode of pain radiation to one lower limb caused by low disc herniation or non-specific low back pain. We studied 11 patients with history of low-disc herniation, 9 patients with history of non-specific low back pain and 10 healthy subjects. Hip strategy alterations were detected by measuring rectus femoris and gluteus maximus activity in bilateral surface polyelectromyographic recordings and by stability measurements on a balance platform. In the surface polyelectromyography study, in both patients' group the value of the average amplitude was higher and the amount of the fluctuations was lower than in healthy subjects. There were no significant differences in stability parameters. A changed pattern of hip muscles activity was detected in the patients without changes in stability parameters. Greater disorder occurs in people in with previous episode of pain radiation to one lower limb caused by low disc herniation than in people with non-specific low back pain.

  5. The Effects of Active Trigger Point of Upper Trapezius Muscle on Its Electromyography Activity and Maximal Isometric Contraction Force during Scapular Plane Elevation (Scaption

    Directory of Open Access Journals (Sweden)

    Zahra Mohammadi

    2014-01-01

    Full Text Available Objective: Trigger points may result in referral pain of their close areas. Recent evidence suggests that latent trigger points although they are not sensitive enough to cause pain, can interfere with the normal muscle function. These myofascial trigger points are estimated as an electro-physiological phenomenon. However, there are a few studies which investigated the effect of these points on the muscle activity. Muscle activity is a determinant factor in injuries which may cause or worsen shoulder-neck pain. The aim of the study was to evaluate upper trapezius muscle activity and delay time at the presence of active trigger point during scapular plane elevation (scaption. Materials & Methods: In a case-control comparative study in spring 2012, Seventeen women with active trigger points (mean age 26.76 y and 17 healthy women (mean age 26.18 y in bio-mechanic laboratory of University of Social Welfare and Rehabilitation sciences (USWR participated in the study. Using surface EMG, the amplitude of muscle activity and the onset time of upper trapezius during scaption, were recorded and analyzed. Results: The maximum amplitude of the upper trapezius muscle activity (during maximal voluntary isometric contraction of 90°scaption in patients showed significant decrease in comparison with the healthy subjects (P=0.01.Also, the onset time of upper trapezius muscle activation time in the patient group was significantly delayed in comparison to the healthy group (P=0.04. Conclusion: At the presence of trigger points in Upper trapezius muscle, muscle activation pattern changes trigger points can change the amplitude and timing of muscle activity and may consequently lead to abnormal patterns of motion of the shoulder girdle. These findings can be used in the prevention and treatment of shoulder disorders.

  6. Investigation of Physiological Properties of Nerves and Muscles Using Electromyography

    Science.gov (United States)

    Roe, Seán M.; Johnson, Christopher D.; Tansey, Etain A.

    2014-01-01

    The measurement and representation of the electrical activity of muscles [electromyography (EMG)] have a long history from the Victorian Era until today. Currently, EMG has uses both as a research tool, in noninvasively recording muscle activation, and clinically in the diagnosis and assessment of nerve and muscle disease and injury as well as in…

  7. Electromyography

    Science.gov (United States)

    ... muscle movement, and other functions) Guillain-Barré syndrome (autoimmune disorder of the nerves that leads to muscle weakness or paralysis) Lambert-Eaton syndrome (autoimmune disorder of the nerves that causes muscle weakness) Multiple ...

  8. Active Particles on Curved Surfaces

    OpenAIRE

    Fily, Yaouen; Baskaran, Aparna; Hagan, Michael F.

    2016-01-01

    Recent studies have highlighted the sensitivity of active matter to boundaries and their geometries. Here we develop a general theory for the dynamics and statistics of active particles on curved surfaces and illustrate it on two examples. We first show that active particles moving on a surface with no ability to probe its curvature only exhibit steady-state inhomogeneities in the presence of orientational order. We then consider a strongly confined 3D ideal active gas and compute its steady-...

  9. Electromyography physiology engineering and noninvasive applications

    CERN Document Server

    Parker, Philip; John Wiley & Sons

    2004-01-01

    "Featuring contributions from key innovators working in the field today, Electromyography reveals the broad applications of EMG data in areas as diverse as neurology, ergonomics, exercise physiology, rehabilitation, movement analysis, biofeedback, and myoelectric control of prostheses." "Electromyography offers physiologists, medical professionals, and students in biomedical engineering a new window into the possibilities of this technology."--Jacket.

  10. Concurrent validity of the pressure biofeedback unit and surface electromyography in measuring transversus abdominis muscle activity in patients with chronic nonspecific low back pain Validade concorrente da unidade de biofeedback pressórico e eletromiografia de superfície na mensuração da atividade muscular do transverso abdominal em pacientes com dor lombar crônica inespecífica

    Directory of Open Access Journals (Sweden)

    Pedro O. P. Lima

    2012-10-01

    Full Text Available BACKGROUND: The Pressure biofeedback unit (PBU is an assessment tool used in clinical practice and research aimed to indirectly analyze the transversus abdominis (TrA muscle activity. The concurrent validity of the PBU in a clinically relevant sample is still unclear. OBJECTIVE: The purpose of this study was to evaluate the concurrent validity and diagnostic accuracy of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain. METHOD: This study was performed using a validation, cross-sectional design. Fifty patients with chronic nonspecific low back pain were recruited for this study. To test the concurrent validity both PBU measures (index test and superficial electromyographic measures (reference-standard test were compared and collected by a physical therapist in a series of voluntary contraction maneuvers of TrA muscle. RESULTS: Participants were on average 22 years old, weighed 63.7 kilos, 1.70 meters height and mean low back pain duration was 1.9 years. It was observed a weak and non-significant Phi coefficient (r=0.2, pCONTEXTUALIZAÇÃO: A Unidade de Biofeedback Pressórico (UBP é uma ferramenta de avaliação usada na prática clínica e pesquisa científica para analisar indiretamente a atividade muscular do transverso abdominal (TrA. A validade concorrente da UBP em uma amostra clinicamente relevante ainda não está esclarecida. OBJETIVO: Avaliar a validade concorrente e acurácia diagnóstica da UBP em mensurar a atividade muscular do TrA em pacientes com dor lombar crônica inespecífica. MÉTODO: Este estudo foi realizado usando um delineamento de validação. Cinquenta pacientes com dor lombar crônica inespecífica foram recrutados. Para testar a validade concorrente, ambas as medidas pressóricas (teste índice e eletromiográficas superficiais (teste padrão de referência foram comparadas e coletadas por um fisioterapeuta a partir de uma manobra de contração voluntária do músculo Tr

  11. Anal sphincter electromyography in patients with Anorectal Dysfunctions

    International Nuclear Information System (INIS)

    Trinchet Soler, Rafael; Hidalgo Marrero, Yanet; Espichicoque Megret, Arianne; Manzano Suarez, Jianeya; Perez Gonzales, Ruth Maite

    2009-01-01

    The purpose of this work is to evaluate the electromyography value of anal sphincter in patients with anorectal dysfunctions. Anorectal dysfunctions are frequent reason of pediatric consultation in children, especially with anal incontinence. A study of series of cases in patient with anorectal dysfunctions was carried out from January 2002 to January of 2006. 65 patients were studied. Anorectal malformations (ARM) represented the predominant affection with 38 patients (58.5%), prevailing the male sex in 25 patients (65.8%). Encopresis and intestinal agagliosis dicrease was observed. Sphincter was found before surgical treatment through electromyography in patients with anorectal malformations and colostomy; in those with definitive operation and open colostomy, it avoided the operation in a patient that did not have muscular activity of the external sphincter. In children already operated and with closed colostomy several electromyography changes were observed in correspondence with different incontinence grades. In encopresis cases the study was useful to rule out sphincter functional alterations. Electromyography was pathological in all the operated patients of intestinal aganglionosis. This procedure was very useful for anal incontinence study that helped to determine and establish the prognosis. (author)

  12. Effects of inspiratory muscle training on respiratory muscle electromyography and dyspnea during exercise in healthy men.

    Science.gov (United States)

    Ramsook, Andrew H; Molgat-Seon, Yannick; Schaeffer, Michele R; Wilkie, Sabrina S; Camp, Pat G; Reid, W Darlene; Romer, Lee M; Guenette, Jordan A

    2017-05-01

    Inspiratory muscle training (IMT) has consistently been shown to reduce exertional dyspnea in health and disease; however, the physiological mechanisms remain poorly understood. A growing body of literature suggests that dyspnea intensity can be explained largely by an awareness of increased neural respiratory drive, as measured indirectly using diaphragmatic electromyography (EMGdi). Accordingly, we sought to determine whether improvements in dyspnea following IMT can be explained by decreases in inspiratory muscle electromyography (EMG) activity. Twenty-five young, healthy, recreationally active men completed a detailed familiarization visit followed by two maximal incremental cycle exercise tests separated by 5 wk of randomly assigned pressure threshold IMT or sham control (SC) training. The IMT group ( n = 12) performed 30 inspiratory efforts twice daily against a 30-repetition maximum intensity. The SC group ( n = 13) performed a daily bout of 60 inspiratory efforts against 10% maximal inspiratory pressure (MIP), with no weekly adjustments. Dyspnea intensity was measured throughout exercise using the modified 0-10 Borg scale. Sternocleidomastoid and scalene EMG was measured using surface electrodes, whereas EMGdi was measured using a multipair esophageal electrode catheter. IMT significantly improved MIP (pre: -138 ± 45 vs. post: -160 ± 43 cmH 2 O, P muscle EMG during exercise in either group. Improvements in dyspnea intensity ratings following IMT in healthy humans cannot be explained by changes in the electrical activity of the inspiratory muscles. NEW & NOTEWORTHY Exertional dyspnea intensity is thought to reflect an increased awareness of neural respiratory drive, which is measured indirectly using diaphragmatic electromyography (EMGdi). We examined the effects of inspiratory muscle training (IMT) on dyspnea, EMGdi, and EMG of accessory inspiratory muscles. IMT significantly reduced submaximal dyspnea intensity ratings but did not change EMG of any

  13. Active Free Surface Density Maps

    Science.gov (United States)

    Çelen, S.

    2016-10-01

    Percolation problems were occupied to many physical problems after their establishment in 1957 by Broadbent and Hammersley. They can be used to solve complex systems such as bone remodeling. Volume fraction method was adopted to set some algorithms in the literature. However, different rate of osteoporosis could be observed for different microstructures which have the same mass density, mechanical stimuli, hormonal stimuli and nutrition. Thus it was emphasized that the bone might have identical porosity with different specific surfaces. Active free surface density of bone refers the used total area for its effective free surface. The purpose of this manuscript is to consolidate a mathematical approach which can be called as “active free surface density maps” for different surface patterns and derive their formulations. Active free surface density ratios were calculated for different Archimedean lattice models according to Helmholtz free energy and they were compared with their site and bond percolation thresholds from the background studies to derive their potential probability for bone remodeling.

  14. Impairment assessment of lateral epicondylitis through electromyography and dynamometry.

    Science.gov (United States)

    Blanchette, Marc-André; Normand, Martin C

    2011-06-01

    To investigate changes in muscular activity and strength of subjects diagnosed with lateral epicondylitis (LE). To assess the appropriateness of these measures in the patient's follow-up. Twenty-four subjects (11 men and 13 women) with LE, were evaluated at baseline and after 5 weeks of an experimental treatment. Measurements included: the (1) pain-free grip (PFG), (2) maximal isometric strength, (3) surface electromyography (EMG) of forearm muscle (healthy and affected), (4) a visual analogue scale (VAS), and (5) the Patient Rated Tennis Elbow Evaluation (PRTEE) (Canadian-French version). All subjects showed improvement in VAS and PRTEE. The maximal isometric strength during flexion and extension of the wrist and the EMG analysis failed to discriminate the affected from the healthy elbow during the initial assessment. Only the PFG measured with the elbow in extension could discriminate elbows with LE from the healthy ones. The use of the PFG with the elbow in extension seems to be the most indicated strength measurement to monitor the recovery of patients with LE. The EMG acquisition protocol used in this research was not adequate to monitor effectively the recovery of LE.

  15. Hydroxamic acid surface active agents

    Directory of Open Access Journals (Sweden)

    El-Sawy, A. A.

    2001-10-01

    Full Text Available p-Hydroxy phenyloctadecanol and p-hydroxy phenyloctadecanoic acid were used as new precursors for the preparation of surface active hydroxamic acid including different moles of propylene oxide. The hydroxamic acid was prepared by the reaction of propenoxylated products with sodium chloroacetate, followed by methyl esterification and the resultant product reacted with hydroxyl amine hydrochloride to give the hydroxamic acid. The structures of prepared hydroxamic acid were confirmed by spectroscopic study. The surface activity of prepared hydroxamic acid was studied; the results revealed that, the prepared hydroxamic acid has pronounced surface activity, the alcohol substrate shows a surface activity superior than the acid substrate.Se han utilizado el p-hidroxifeniloctadecanol y el ácido p-hidroxifeniloctadecanoico como nuevos precursores para la preparación de tensioactivos derivados del ácido hidroxámico, que incluyen diferentes moles de óxido de propileno. El ácido hidroxámico se preparó por reacción de los productos propenoxilados con cloroacetato sódico, seguido de la formación de ésteres metílicos, y los productos resultantes se hicieron reaccionar con clorhidrato de hidroxilamina para dar los derivados del ácido hidroxámico. Las estructuras de los derivados preparados del ácido hidroxámico, se confirmaron por técnicas espectroscópicas, estudiándose su actividad superficial cuyos resultados mostraron que dichos compuestos tenían un alto valor. La actividad superficial del sustrato alcohólico fue mayor que la del sustrato ácido.

  16. Laryngeal electromyography in movement disorders: preliminary data

    Directory of Open Access Journals (Sweden)

    Kimaid Paulo A.T.

    2004-01-01

    Full Text Available This study describes preliminary laryngeal electromyography (LEMG data and botulinum toxin treatment in patients with dysphonia due to movement disorders. Twenty-five patients who had been clinically selected for botulinum toxin administration were examined, 19 with suspected laryngeal dystonia or spasmodic dysphonia (SD, 5 with vocal tremor, and 1 with Gilles de la Tourette syndrome (GTS. LEMG evaluations were performed before botulinum toxin administration using monopolar electrodes. Electromyography was consistent with dystonia in 14 patients and normal in 5, and differences in frequency suggesting essential tremor in 3 and Parkinson tremors in 2. The different LEMG patterns and significant improvement in our patients from botulinum toxin therapy has led us to perform laryngeal electromyography as a routine in UNICAMP movement disorders ambulatory.

  17. Electromyography Exposes Heterogeneity in Muscle Co-Contraction following Stroke

    Directory of Open Access Journals (Sweden)

    Caitlin L. Banks

    2017-12-01

    Full Text Available Walking after stroke is often described as requiring excessive muscle co-contraction, yet, evidence that co-contraction is a ubiquitous motor control strategy for this population remains inconclusive. Co-contraction, the simultaneous activation of agonist and antagonist muscles, can be assessed with electromyography (EMG but is often described qualitatively. Here, our goal is to determine if co-contraction is associated with gait impairments following stroke. Fifteen individuals with chronic stroke and nine healthy controls walked on an instrumented treadmill at self-selected speed. Surface EMGs were collected from the medial gastrocnemius (MG, soleus (SOL, and tibialis anterior (TA of each leg. EMG envelope amplitudes were assessed in three ways: (1 no normalization, (2 normalization to the maximum value across the gait cycle, or (3 normalization to maximal M-wave. Three co-contraction indices were calculated across each agonist/antagonist muscle pair (MG/TA and SOL/TA to assess the effect of using various metrics to quantify co-contraction. Two factor ANOVAs were used to compare effects of group and normalization for each metric. Co-contraction during the terminal stance (TSt phase of gait is not different between healthy controls and the paretic leg of individuals post-stroke, regardless of the metric used to quantify co-contraction. Interestingly, co-contraction was similar between M-max and non-normalized EMG; however, normalization does not impact the ability to resolve group differences. While a modest correlation is revealed between the amount of TSt co-contraction and walking speed, the relationship is not sufficiently strong to motivate further exploration of a causal link between co-contraction and walking function after stroke. Co-contraction does not appear to be a common strategy employed by individuals after stroke. We recommend exploration of alternative EMG analysis approaches in an effort to learn more about the causal

  18. A cross-sectional electromyography assessment in linear scleroderma patients

    Science.gov (United States)

    2014-01-01

    Background Muscle atrophy and asymmetric extremity growth is a common feature of linear scleroderma (LS). Extra-cutaneous features are also common and primary neurologic involvement, with sympathetic dysfunction, may have a pathogenic role in subcutaneous and muscle atrophy. The aim was investigate nerve conduction and muscle involvement by electromyography in pediatric patients with LS. Methods We conducted a retrospective review of LS pediatric patients who had regular follow up at a single pediatric center from 1997–2013. We selected participants if they had consistently good follow up and enrolled consecutive patients in the study. We examined LS photos as well as clinical, serological and imaging findings. Electromyograms (EMG) were performed with bilateral symmetric technique, using surface and needle electrodes, comparing the affected side with the contralateral side. Abnormal muscle activity was categorized as a myopathic or neurogenic pattern. Results Nine LS subjects were selected for EMG, 2 with Parry-Romberg/Hemifacial Atrophy Syndrome, 7 linear scleroderma of an extremity and 2 with mixed forms (linear and morphea). Electromyogram analysis indicated that all but one had asymmetric myopathic pattern in muscles underlying the linear streaks. Motor and sensory nerve conduction was also evaluated in upper and lower limbs and one presented a neurogenic pattern. Masticatory muscle testing showed a myopathic pattern in the atrophic face of 2 cases with head and face involvement. Conclusion In our small series of LS patients, we found a surprising amount of muscle dysfunction by EMG. The muscle involvement may be possibly related to a secondary peripheral nerve involvement due to LS inflammation and fibrosis. Further collaborative studies to confirm these findings are needed. PMID:25053924

  19. Electromyography Activation of the Lower-Limb Muscles Adopting a Physioball and Elastic Band to Stabilize the Knee Joint During Multiple Sets With Submaximal Loads.

    Science.gov (United States)

    Paz, Gabriel Andrade; DeFreitas, Jason; de Freitas Maia, Marianna; Silva, Jurandir; Lima, Vicente; Miranda, Humberto

    2017-09-01

    Crossover design. Excessive valgus and varus force which affected the knee joint during dynamic tasks has been often associated to lower extremity injuries. Strategies to increase the resistance against these asymmetries (eg, the use of a physioball between the knees or elastic bands around the knees) are often applied in rehabilitation and conditioning programs. The purpose of this study was to investigate the effect of performing leg press (LP) 45° using a physioball and elastic band over multiple sets with submaximal loads on electromyographic (EMG) amplitude and fatigue indices. 18 trained females volunteered (age: 24.4 ± 2.1 y; height: 168.1 ± 4 cm; body mass: 65.1 ± 4.4 kg) participated in this study. The 10 repetition maximum (RM) loads were determined for the LP. Then, 3 experimental protocols were followed in a randomized crossover design over 3 nonconsecutive days: control protocol-the participants performed 4 LP sets; physioball between knees-4 LP sets were performed with the physioball between the knees; elastic band-4 LP sets were performed with the elastic band involving the knees. Ten repetitions were performed during each set with 70% of 10-RM loads; EMG spectral indices (CRMS and Cf5) was collected from the biceps femoris (BF), vastus lateralis (VL), vastus medialis obliquus (VMO), and rectus femoris (RF) muscles. Higher levels of CRMS and Cf5 were noted for RF, VL, and VM muscles using the physioball and elastic band when compared with control protocol, respectively. CRMS index of BF muscle was significantly higher using physioball and elastic band protocol versus control condition, respectively. Therefore, both physioball and elastic band can be adopted during LP with the goal to reduce excessive varus and valgus forces, respectively, even performing consecutive sets with submaximal loads. Furthermore, this may be an interesting alternative to increasing quadriceps activation and improving the knee joint stabilization.

  20. A simple test of muscle coactivation estimation using electromyography

    Directory of Open Access Journals (Sweden)

    U.F. Ervilha

    2012-10-01

    Full Text Available In numerous motor tasks, muscles around a joint act coactively to generate opposite torques. A variety of indexes based on electromyography signals have been presented in the literature to quantify muscle coactivation. However, it is not known how to estimate it reliably using such indexes. The goal of this study was to test the reliability of the estimation of muscle coactivation using electromyography. Isometric coactivation was obtained at various muscle activation levels. For this task, any coactivation measurement/index should present the maximal score (100% of coactivation. Two coactivation indexes were applied. In the first, the antagonistic muscle activity (the lower electromyographic signal between two muscles that generate opposite joint torques is divided by the mean between the agonistic and antagonistic muscle activations. In the second, the ratio between antagonistic and agonistic muscle activation is calculated. Moreover, we computed these indexes considering different electromyographic amplitude normalization procedures. It was found that the first algorithm, with all signals normalized by their respective maximal voluntary coactivation, generates the index closest to the true value (100%, reaching 92 ± 6%. In contrast, the coactivation index value was 82 ± 12% when the second algorithm was applied and the electromyographic signal was not normalized (P < 0.04. The new finding of the present study is that muscle coactivation is more reliably estimated if the EMG signals are normalized by their respective maximal voluntary contraction obtained during maximal coactivation prior to dividing the antagonistic muscle activity by the mean between the agonistic and antagonistic muscle activations.

  1. Surface active monomers synthesis, properties, and application

    CERN Document Server

    Borzenkov, Mykola

    2014-01-01

    This brief includes information on the background?of and development of synthesis of various types of surface active monomers. The authors explain the importance of utilization of surface active monomers for creation of surface active polymers? and the various biomedical applications of such compounds . This brief introduces techniques for the synthesis of novel types of surface active monomers, their colloidal and polymerizable properties and application for needs of medicine and biology.

  2. Recognition of handwriting from electromyography.

    Directory of Open Access Journals (Sweden)

    Michael Linderman

    Full Text Available Handwriting--one of the most important developments in human culture--is also a methodological tool in several scientific disciplines, most importantly handwriting recognition methods, graphology and medical diagnostics. Previous studies have relied largely on the analyses of handwritten traces or kinematic analysis of handwriting; whereas electromyographic (EMG signals associated with handwriting have received little attention. Here we show for the first time, a method in which EMG signals generated by hand and forearm muscles during handwriting activity are reliably translated into both algorithm-generated handwriting traces and font characters using decoding algorithms. Our results demonstrate the feasibility of recreating handwriting solely from EMG signals - the finding that can be utilized in computer peripherals and myoelectric prosthetic devices. Moreover, this approach may provide a rapid and sensitive method for diagnosing a variety of neurogenerative diseases before other symptoms become clear.

  3. Use of electromyography measurement in human body modeling

    Directory of Open Access Journals (Sweden)

    Valdmanová L.

    2011-06-01

    Full Text Available The aim of this study is to test the use of the human body model for the muscle activity computation. This paper shows the comparison of measured and simulated muscle activities. Muscle active states of biceps brachia muscle are monitored by method called electromyography (EMG in a given position and for given subsequently increasing loads. The same conditions are used for simulation using a human body model (Hynčík, L., Rigid Body Based Human Model for Crash Test Purposes, EngineeringMechanics, 5 (8 (2001 1–6. This model consists of rigid body segments connected by kinematic joints and involves all major muscle bunches. Biceps brachia active states are evaluated by a special muscle balance solver. Obtained simulation results show the acceptable correlation with the experimental results. The analysis shows that the validation procedure of muscle activities determination is usable.

  4. Biocatalytic Route to Surface Active Lipid

    DEFF Research Database (Denmark)

    Cheong, Ling-Zhi; Xu, Xuebing

    Lipid can be structurally modified in order to attain improved functional properties. This work look into the possibilities of developing surface active lipids with improved functional properties through biocatalytic route. Biocatalytic route to surface active lipid are usually complex involving ...... distinct self assembling property and find useful application in surfactant industry.......Lipid can be structurally modified in order to attain improved functional properties. This work look into the possibilities of developing surface active lipids with improved functional properties through biocatalytic route. Biocatalytic route to surface active lipid are usually complex involving...

  5. A Novel Hybrid Model for Drawing Trace Reconstruction from Multichannel Surface Electromyographic Activity.

    Science.gov (United States)

    Chen, Yumiao; Yang, Zhongliang

    2017-01-01

    Recently, several researchers have considered the problem of reconstruction of handwriting and other meaningful arm and hand movements from surface electromyography (sEMG). Although much progress has been made, several practical limitations may still affect the clinical applicability of sEMG-based techniques. In this paper, a novel three-step hybrid model of coordinate state transition, sEMG feature extraction and gene expression programming (GEP) prediction is proposed for reconstructing drawing traces of 12 basic one-stroke shapes from multichannel surface electromyography. Using a specially designed coordinate data acquisition system, we recorded the coordinate data of drawing traces collected in accordance with the time series while 7-channel EMG signals were recorded. As a widely-used time domain feature, Root Mean Square (RMS) was extracted with the analysis window. The preliminary reconstruction models can be established by GEP. Then, the original drawing traces can be approximated by a constructed prediction model. Applying the three-step hybrid model, we were able to convert seven channels of EMG activity recorded from the arm muscles into smooth reconstructions of drawing traces. The hybrid model can yield a mean accuracy of 74% in within-group design (one set of prediction models for all shapes) and 86% in between-group design (one separate set of prediction models for each shape), averaged for the reconstructed x and y coordinates. It can be concluded that it is feasible for the proposed three-step hybrid model to improve the reconstruction ability of drawing traces from sEMG.

  6. Active biofeedback changes the spatial distribution of upper trapezius muscle activity during computer work

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2010-01-01

    The aim of this study was to investigate the spatio-temporal effects of advanced biofeedback by inducing active and passive pauses on the trapezius activity pattern using high-density surface electromyography (HD-EMG). Thirteen healthy male subjects performed computer work with superimposed feedb...... benefit of superimposed muscle contraction in relation to the spatial organization of muscle activity during computer work.......The aim of this study was to investigate the spatio-temporal effects of advanced biofeedback by inducing active and passive pauses on the trapezius activity pattern using high-density surface electromyography (HD-EMG). Thirteen healthy male subjects performed computer work with superimposed...

  7. The effects of surface condition on abdominal muscle activity during single-legged hold exercise.

    Science.gov (United States)

    Ha, Sung-min; Oh, Jae-seop; Jeon, In-cheol; Kwon, Oh-yun

    2015-02-01

    To treat low-back pain, various spinal stability exercises are commonly used to improve trunk muscle function and strength. Because human movement for normal daily activity occurs in multi-dimensions, the importance of exercise in multi-dimensions or on unstable surfaces has been emphasized. Recently, a motorized rotating platform (MRP) for facilitating multi-dimensions dynamic movement was introduced for clinical use. However, the abdominal muscle activity with this device has not been reported. The purpose of this study was to compare the abdominal muscle activity (rectus abdominis, external and internal oblique muscles) during an active single-leg-hold (SLH) exercise on a floor (stable surface), foam roll, and motorized rotating platform (MRP). Thirteen healthy male subjects participated in this study. Using electromyography, the abdominal muscle activity was measured while the subjects performed SLH exercises on floor (stable surface), foam roll, and MRP. There were significant differences in the abdominal muscle activities among conditions (P.05) (Fig. 2). After the Bonferroni correction, however, no significant differences among conditions remained, except for differences in both side IO muscle activity between the floor and foam roll conditions (padjactivities of both side of RA and IO, and Rt. EO compared to floor condition. However, there were no significant differences in abdominal muscles activity in the multiple comparison between conditions (mean difference were smaller than the standard deviation in the abdominal muscle activities) (padj>0.017), except for differences in both side IO muscle activity between the floor (stable surface) and foam roll (padj<0.017) (effect size: 0.79/0.62 (non-supporting/supporting leg) for foam-roll versus floor). Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Preliminary investigation of an electromyography-controlled video game as a home program for persons in the chronic phase of stroke recovery.

    Science.gov (United States)

    Donoso Brown, Elena V; McCoy, Sarah Westcott; Fechko, Amber S; Price, Robert; Gilbertson, Torey; Moritz, Chet T

    2014-08-01

    To investigate the preliminary effectiveness of surface electromyography (sEMG) biofeedback delivered via interaction with a commercial computer game to improve motor control in chronic stroke survivors. Single-blinded, 1-group, repeated-measures design: A1, A2, B, A3 (A, assessment; B, intervention). Laboratory and participants' homes. A convenience sample of persons (N=9) between 40 and 75 years of age with moderate to severe upper extremity motor impairment and at least 6 months poststroke completed the study. The electromyography-controlled video game system targeted the wrist muscle activation with the goal of increasing selective muscle activation. Participants received several laboratory training sessions with the system and then were instructed to use the system at home for 45 minutes, 5 times per week for the following 4 weeks. Primary outcome measures included duration of system use, sEMG during home play, and pre/post sEMG measures during active wrist motion. Secondary outcomes included kinematic analysis of movement and functional outcomes, including the Wolf Motor Function Test and the Chedoke Arm and Hand Activity Inventory-9. One third of participants completed or exceeded the recommended amount of system use. Statistically significant changes were observed on both game play and pre/post sEMG outcomes. Limited carryover, however, was observed on kinematic or functional outcomes. This preliminary investigation indicates that use of the electromyography-controlled video game impacts muscle activation. Limited changes in kinematic and activity level outcomes, however, suggest that the intervention may benefit from the inclusion of a functional activity component. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  9. Wavelet transform analysis of electromyography kung fu strikes data.

    Science.gov (United States)

    Neto, Osmar Pinto; Marzullo, Ana Carolina de Miranda

    2009-11-01

    In martial arts and contact sports strikes are performed at near maximum speeds. For that reason, electromyography (EMG) analysis of such movements is non-trivial. This paper has three main goals: firstly, to investigate the differences in the EMG activity of muscles during strikes performed with and without impacts; secondly, to assess the advantages of using Sum of Significant Power (SSP) values instead of root mean square (rms) values when analyzing EMG data; and lastly to introduce a new method of calculating median frequency values using wavelet transforms (WMDF). EMG data of the deltoid anterior (DA), triceps brachii (TB) and brachioradialis (BR) muscles were collected from eight Kung Fu practitioners during strikes performed with and without impacts. SSP results indicated significant higher muscle activity (p = 0.023) for the strikes with impact. WMDF results, on the other hand, indicated significant lower values (p = 0. 007) for the strikes with impact. SSP results presented higher sensitivity than rms to quantify important signal differences and, at the same time, presented lower inter-subject coefficient of variations. The result of increase in SSP values and decrease in WMDF may suggest better synchronization of motor units for the strikes with impact performed by the experienced Kung Fu practitioners. Key PointsThe results show higher muscle activity and lower electromyography median frequencies for strikes with impact compared to strikes without.SSP results presented higher sensitivity and lower inter-subject coefficient of variations than rms results.Kung Fu palm strikes with impact may present better motor units' synchronization than strikes without.

  10. Immobilization of Active Bacteriophages on Polyhydroxyalkanoate Surfaces.

    Science.gov (United States)

    Wang, Chanchan; Sauvageau, Dominic; Elias, Anastasia

    2016-01-20

    A rapid, efficient technique for the attachment of bacteriophages (phages) onto polyhydroxyalkanoate (PHA) surfaces has been developed and compared to three reported methods for phage immobilization. Polymer surfaces were modified to facilitate phage attachment using (1) plasma treatment alone, (2) plasma treatment followed by activation by 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (sulfo-NHS), (3) plasma-initiated acrylic acid grafting, or (4) plasma-initiated acrylic acid grafting with activation by EDC and sulfo-NHS. The impact of each method on the surface chemistry of PHA was investigated using contact angle analysis and X-ray photoelectron spectroscopy. Each of the four treatments was shown to result in both increased hydrophilicity and in the modification of the surface functional groups. Modified surfaces were immersed in suspensions of phage T4 for immobilization. The highest level of phage binding was observed for the surfaces modified by plasma treatment alone. The change in chemical bond states observed for surfaces that underwent plasma treatment is suspected to be the cause of the increased binding of active phages. Plasma-treated surfaces were further analyzed through phage-staining and fluorescence microscopy to assess the surface density of immobilized phages and their capacity to capture hosts. The infective capability of attached phages was confirmed by exposing the phage-immobilized surfaces to the host bacteria Escherichia coli in both plaque and infection dynamic assays. Plasma-treated surfaces with immobilized phages displayed higher infectivity than surfaces treated with other methods; in fact, the equivalent initial multiplicity of infection was 2 orders of magnitude greater than with other methods. Control samples - prepared by immersing polymer surfaces in phage suspensions (without prior plasma treatment) - did not show any bacterial growth inhibition, suggesting they did not bind

  11. Abdominal muscle EMG-activity during bridge exercises on stable and unstable surfaces.

    Science.gov (United States)

    Czaprowski, Dariusz; Afeltowicz, Anna; Gębicka, Anna; Pawłowska, Paulina; Kędra, Agnieszka; Barrios, Carlos; Hadała, Michał

    2014-08-01

    To assess abdominal muscles (AM) activity during prone, side, and supine bridge on stable and unstable surfaces (BOSU, Swiss Ball). Prospective comparison study. Research laboratory. Thirty-three healthy volunteers from a university population. Surface electromyography of the rectus abdominis (RA), the external oblique (EO) and the internal oblique with the transversus abdominis (IO-TA). The AM exhibited the highest activity during prone bridge on a Swiss Ball (RA, EO, IO-TA 44.7 ± 19.2, 54.7 ± 22.9, 36.8 ± 18.6 in % of MVC, respectively). The lowest activity was observed during supine bridge on a stable surface and a BOSU (under 5.0). The lowest ratio analyzed on the basis of the relation of EO and IO-TA activity to RA was obtained during prone bridge on the Swiss Ball (1.4 ± 0.7 for EO, 0.9 ± 0.5 for IO-TA). The highest ratio was obtained during prone bridge on stable surface and supine bridges. The highest level of activity in the abdominal muscles is achieved during prone bridge on a Swiss Ball. However, this exercise provided the lowest activity of the EO and IO-TA in relation to RA. It is essential to conduct further studies verifying the usefulness of using Swiss Ball during core stability training. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Active micromixer using surface acoustic wave streaming

    Science.gov (United States)

    Branch,; Darren W. , Meyer; Grant D. , Craighead; Harold, G [Ithaca, NY

    2011-05-17

    An active micromixer uses a surface acoustic wave, preferably a Rayleigh wave, propagating on a piezoelectric substrate to induce acoustic streaming in a fluid in a microfluidic channel. The surface acoustic wave can be generated by applying an RF excitation signal to at least one interdigital transducer on the piezoelectric substrate. The active micromixer can rapidly mix quiescent fluids or laminar streams in low Reynolds number flows. The active micromixer has no moving parts (other than the SAW transducer) and is, therefore, more reliable, less damaging to sensitive fluids, and less susceptible to fouling and channel clogging than other types of active and passive micromixers. The active micromixer is adaptable to a wide range of geometries, can be easily fabricated, and can be integrated in a microfluidic system, reducing dead volume. Finally, the active micromixer has on-demand on/off mixing capability and can be operated at low power.

  13. ECG artifact cancellation in surface EMG signals by fractional order calculus application.

    Science.gov (United States)

    Miljković, Nadica; Popović, Nenad; Djordjević, Olivera; Konstantinović, Ljubica; Šekara, Tomislav B

    2017-03-01

    New aspects for automatic electrocardiography artifact removal from surface electromyography signals by application of fractional order calculus in combination with linear and nonlinear moving window filters are explored. Surface electromyography recordings of skeletal trunk muscles are commonly contaminated with spike shaped artifacts. This artifact originates from electrical heart activity, recorded by electrocardiography, commonly present in the surface electromyography signals recorded in heart proximity. For appropriate assessment of neuromuscular changes by means of surface electromyography, application of a proper filtering technique of electrocardiography artifact is crucial. A novel method for automatic artifact cancellation in surface electromyography signals by applying fractional order calculus and nonlinear median filter is introduced. The proposed method is compared with the linear moving average filter, with and without prior application of fractional order calculus. 3D graphs for assessment of window lengths of the filters, crest factors, root mean square differences, and fractional calculus orders (called WFC and WRC graphs) have been introduced. For an appropriate quantitative filtering evaluation, the synthetic electrocardiography signal and analogous semi-synthetic dataset have been generated. The examples of noise removal in 10 able-bodied subjects and in one patient with muscle dystrophy are presented for qualitative analysis. The crest factors, correlation coefficients, and root mean square differences of the recorded and semi-synthetic electromyography datasets showed that the most successful method was the median filter in combination with fractional order calculus of the order 0.9. Statistically more significant (p ECG peak reduction was obtained by the median filter application compared to the moving average filter in the cases of low level amplitude of muscle contraction compared to ECG spikes. The presented results suggest that the

  14. Technical activities, 1990: Surface Science Division

    International Nuclear Information System (INIS)

    Powell, C.J.

    1991-05-01

    The report summarizes technical activities and accomplishments of the NIST Surface Science Division during Fiscal Year 1990. Overviews are presented of the Division and of its three constituent groups: Surface Dynamical Processes, Thin Films and Interfaces, and Surface Spectroscopies and Standards. These overviews are followed by reports of selected technical accomplishments during the year. A summary is given of Division outputs and interactions that includes lists of publications, talks, committee assignments, seminars (including both Division seminars and Interface Science seminars arranged through the Division), conferences organized, and a standard reference material certified. Finally, lists are given of Division staff and of guest scientists who have worked in the Division during the past year

  15. JCMT active surface control system: implementation

    Science.gov (United States)

    Smith, Ian A.

    1998-05-01

    The James Clerk Maxwell Telescope on the summit of Mauna Kea in Hawaii is a 15 meter sub-millimeter telescope which operates in the 350 microns to 2 millimeter region. The primary antenna surface consists of 276 panels, each of which is positioned by 3 stepper motors. In order to achieve the highest possible surface accuracy we are embarking upon a project to actively control the position of the panels adjuster system is based on a 6809 micro connected to the control computer by a GPIB interface. This system is slow and inflexible and it would prove difficult to build an active surface control system with it. Part of the upgrade project is to replace the existing micro with a 68060 VME micro. The poster paper will describe how the temperature of the antenna is monitored with the new system, how a Finite Element Analyses package transforms temperature changes into a series of panel adjuster moves, and how these moves are then applied to the surface. The FEA package will run on a high end Sun workstation. A series of DRAMA tasks distributed between the workstation and the Baja 68060 VxWorks Active Surface Control System micro will control the temperature monitoring, FEA and panel adjustment activities. Users can interact with the system via a Tcl/TK based GUI.

  16. Bactericidal activity of biomimetic diamond nanocone surfaces.

    Science.gov (United States)

    Fisher, Leanne E; Yang, Yang; Yuen, Muk-Fung; Zhang, Wenjun; Nobbs, Angela H; Su, Bo

    2016-03-17

    The formation of biofilms on implant surfaces and the subsequent development of medical device-associated infections are difficult to resolve and can cause considerable morbidity to the patient. Over the past decade, there has been growing recognition that physical cues, such as surface topography, can regulate biological responses and possess bactericidal activity. In this study, diamond nanocone-patterned surfaces, representing biomimetic analogs of the naturally bactericidal cicada fly wing, were fabricated using microwave plasma chemical vapor deposition, followed by bias-assisted reactive ion etching. Two structurally distinct nanocone surfaces were produced, characterized, and the bactericidal ability examined. The sharp diamond nanocone features were found to have bactericidal capabilities with the surface possessing the more varying cone dimension, nonuniform array, and decreased density, showing enhanced bactericidal ability over the more uniform, highly dense nanocone surface. Future research will focus on using the fabrication process to tailor surface nanotopographies on clinically relevant materials that promote both effective killing of a broader range of microorganisms and the desired mammalian cell response. This study serves to introduce a technology that may launch a new and innovative direction in the design of biomaterials with capacity to reduce the risk of medical device-associated infections.

  17. Activation of interfacial enzymes at membrane surfaces

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Andresen, Thomas Lars; Halperin, Avi

    2006-01-01

    A host of water-soluble enzymes are active at membrane surfaces and in association with membranes. Some of these enzymes are involved in signalling and in modification and remodelling of the membranes. A special class of enzymes, the phospholipases, and in particular secretory phospholipase A2 (s...

  18. Plasma-Surface Interaction Activities in KSTAR

    NARCIS (Netherlands)

    Hong, S. H.; Yu, Y.; Kim, K. P.; Bak, J. G.; Park, H. J.; Oh, Y. S.; Chung, J.; Nam, Y. U.; Bang, E. N.; Kim, K. R.; Litnovsky, A.; Hellwig, M.; Matveev, D.; Komm, M.; van den Berg, M. A.; Kim, W. C.; Kim, H. K.; Rho, T. H.; Chu, Y.; Oh, Y. K.; Yang, H. L.; Park, K. R.; Chung, K. S.; Kstar Team,

    2013-01-01

    Selected topics of Plasma-Surface Interaction (PSI) activities in KSTAR are briefly introduced. SOL parameter measurements, particle balance and fuel retention, in-vessel dust research, and finally tungsten R & D are discussed. Some quantitative numbers from the initial phase of the operation

  19. Predicting 3D lip shapes using facial surface EMG

    NARCIS (Netherlands)

    Eskes, Merijn; van Alphen, Maarten J. A.; Balm, Alfons J. M.; Smeele, Ludi E.; Brandsma, Dieta; van der Heijden, Ferdinand

    2017-01-01

    Aim The aim of this study is to prove that facial surface electromyography (sEMG) conveys sufficient information to predict 3D lip shapes. High sEMG predictive accuracy implies we could train a neural control model for activation of biomechanical models by simultaneously recording sEMG signals and

  20. Intramuscular pressure and electromyography as indexes of force during isokinetic exercise

    Science.gov (United States)

    Aratow, M.; Ballard, R. E.; Grenshaw, A. G.; Styf, J.; Watenpaugh, D. E.; Kahan, N. J.; Hargens, A. R.

    1993-01-01

    A direct method for measuring force production of specific muscles during dynamic exercise is presently unavailable. Previous studies indicate that both intramuscular pressure (IMP) and electromyography (EMG) correlate linearly with muscle contraction force during isometric exercise. The objective of this study was to compare IMP and EMG as linear assessors of muscle contraction force during dynamic exercise. IMP and surface EMG activity were recorded during concentric and eccentric isokinetic plantarflexion and dorsiflexion of the ankle joint from the tibialis anterior (TA) and soleus (SOL) muscles of nine male volunteers. Ankle torque was measured using a dynamometer, and IMP was measured via catheterization. IMP exhibited better linear correlation than EMG with ankle joint torque during concentric contractions of the SOL and the TA, as well as during eccentric contractions. IMP provides a better index of muscle contraction force than EMG during concentric and eccentric exercise through the entire range of torque. IMP reflects intrinsic mechanical properties of individual muscles, such as length-tension relationships, which EMG is unable to assess.

  1. Electromyography in the four competitive swimming strokes: a systematic review.

    Science.gov (United States)

    Martens, Jonas; Figueiredo, Pedro; Daly, Daniel

    2015-04-01

    The aim of this paper is to give an overview on 50 years of research in electromyography in the four competitive swimming strokes (crawl, breaststroke, butterfly, and backstroke). A systematic search of the existing literature was conducted using the combined keywords "swimming" and "EMG" on studies published before August 2013, in the electronic databases PubMed, ISI Web of Knowledge, SPORT discus, Academic Search Elite, Embase, CINAHL and Cochrane Library. The quality of each publication was assessed by two independent reviewers using a custom made checklist. Frequency of topics, muscles studied, swimming activities, populations, types of equipment and data treatment were determined from all selected papers and, when possible, results were compared and contrasted. In the first 20 years of EMG studies in swimming, most papers were published as congress proceedings. The methodological quality was low. Crawl stroke was most often studied. There was no standardized manner of defining swimming phases, normalizing the data or of presenting the results. Furthermore, the variability around the mean muscle activation patterns is large which makes it difficult to define a single pattern applicable to all swimmers in any activity examined. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Mechanotransductive surfaces for reversible biocatalysis activation

    Science.gov (United States)

    Mertz, Damien; Vogt, Cédric; Hemmerlé, Joseph; Mutterer, Jérôme; Ball, Vincent; Voegel, Jean-Claude; Schaaf, Pierre; Lavalle, Philippe

    2009-09-01

    Fibronectin, like other proteins involved in mechanotransduction, has the ability to exhibit recognition sites under mechanical stretch. Such cryptic sites are buried inside the protein structure in the native fold and become exposed under an applied force, thereby activating specific signalling pathways. Here, we report the design of new active polymeric nanoassembled surfaces that show some similarities to these cryptic sites. These nanoassemblies consist of a first polyelectrolyte multilayer stratum loaded with enzymes and capped with a second polyelectrolyte multilayer acting as a mechanically sensitive nanobarrier. The biocatalytic activity of the film is switched on/off reversibly by mechanical stretching, which exposes enzymes through the capping barrier, similarly to mechanisms involved in proteins during mechanotransduction. This first example of a new class of biologically inspired surfaces should have great potential in the design of various devices aimed to trigger and modulate chemical reactions by mechanical action with applications in the field of microfluidic devices or mechanically controlled biopatches for example.

  3. Active colloidal propulsion over a crystalline surface

    Science.gov (United States)

    Choudhury, Udit; Straube, Arthur V.; Fischer, Peer; Gibbs, John G.; Höfling, Felix

    2017-12-01

    We study both experimentally and theoretically the dynamics of chemically self-propelled Janus colloids moving atop a two-dimensional crystalline surface. The surface is a hexagonally close-packed monolayer of colloidal particles of the same size as the mobile one. The dynamics of the self-propelled colloid reflects the competition between hindered diffusion due to the periodic surface and enhanced diffusion due to active motion. Which contribution dominates depends on the propulsion strength, which can be systematically tuned by changing the concentration of a chemical fuel. The mean-square displacements (MSDs) obtained from the experiment exhibit enhanced diffusion at long lag times. Our experimental data are consistent with a Langevin model for the effectively two-dimensional translational motion of an active Brownian particle in a periodic potential, combining the confining effects of gravity and the crystalline surface with the free rotational diffusion of the colloid. Approximate analytical predictions are made for the MSD describing the crossover from free Brownian motion at short times to active diffusion at long times. The results are in semi-quantitative agreement with numerical results of a refined Langevin model that treats translational and rotational degrees of freedom on the same footing.

  4. Surface active properties of lipid nanocapsules.

    Directory of Open Access Journals (Sweden)

    Celia R A Mouzouvi

    Full Text Available Lipid nanocapsules (LNCs are biomimetic nanocarriers used for the encapsulation of a broad variety of active ingredients. Similar to surface active compounds, LNCs contain both hydrophilic and hydrophobic parts in their structure. Moreover, the components of LNCs, macrogol 15 hydroxystearate (MHS and lecithin, are known for their surface active properties. Therefore, the aim of this paper was to investigate the capability of the LNCs to decrease surface tension using two techniques: drop tensiometry and the Wilhelmy plate method. LNCs with diameters ranging from 30 to 100 nm were successfully obtained using a phase inversion technique. The LNCs' properties, such as size and zeta potential, depend on the composition. LNCs exhibit a lower limiting surface tension compared to MHS (34.8-35.0 mN/m and 37.7-38.8 mN/m, respectively, as confirmed by both drop tensiometry and the Wilhelmy plate method. LNCs have exhibited a saturated interfacial concentration (SIC that was 10-fold higher than the critical micellar concentration (CMC of MHS or the SIC of binary and ternary mixtures of LNC ingredients. The SIC of the LNC formulations depended on the mass mixing ratio of the MHS/triglycerides but not on the presence of lecithin. The CMC/SIC values measured by the Wilhelmy plate method were higher than those obtained using drop tensiometry because of the longer duration of the tensiometry measurement. In conclusion, the surfactant-like properties of the LNCs offer new possibilities for medical and pharmaceutical applications.

  5. No difference in 1RM strength and muscle activation during the barbell chest press on a stable and unstable surface.

    Science.gov (United States)

    Goodman, Craig A; Pearce, Alan J; Nicholes, Caleb J; Gatt, Brad M; Fairweather, Ian H

    2008-01-01

    Exercise or Swiss balls are increasingly being used with conventional resistance exercises. There is little evidence supporting the efficacy of this approach compared to traditional resistance training on a stable surface. Previous studies have shown that force output may be reduced with no change in muscle electromyography (EMG) activity while others have shown increased muscle EMG activity when performing resistance exercises on an unstable surface. This study compared 1RM strength, and upper body and trunk muscle EMG activity during the barbell chest press exercise on a stable (flat bench) and unstable surface (exercise ball). After familiarization, 13 subjects underwent testing for 1RM strength for the barbell chest press on both a stable bench and an exercise ball, each separated by at least 7 days. Surface EMG was recorded for 5 upper body muscles and one trunk muscle from which average root mean square of the muscle activity was calculated for the whole 1RM lift and the concentric and eccentric phases. Elbow angle during each lift was recorded to examine any range-of-motion differences between the two surfaces. The results show that there was no difference in 1RM strength or muscle EMG activity for the stable and unstable surfaces. In addition, there was no difference in elbow range-of-motion between the two surfaces. Taken together, these results indicate that there is no reduction in 1RM strength or any differences in muscle EMG activity for the barbell chest press exercise on an unstable exercise ball when compared to a stable flat surface. Moreover, these results do not support the notion that resistance exercises performed on an exercise ball are more efficacious than traditional stable exercises.

  6. Electromyography and the study of sports movements: a review.

    Science.gov (United States)

    Clarys, J P; Cabri, J

    1993-10-01

    Within electromyography (EMG), a particular specialty has been developed wherein the aim is to use EMG for the study of muscular function and co-ordination. This area of research is usually called kinesiological EMG. The general aims of kinesiological EMG are to analyse the function and co-ordination of muscles in different movements and postures, in healthy subjects as well as in the disabled, in skilled actions as well as during training, in humans as well as in animals, under laboratory conditions as well as during daily or vocational activities. This is often done by a combination of electromyographical and kinesiological or biomechanical measurement techniques. Because there are over 400 skeletal muscles in the human body and both irregular and complex involvement of the muscles may occur in neuromuscular diseases and in voluntary occupational or sports movements, it is impossible to sample all of the muscles of the entire body during the performance of complex motor skills. In addition, the measurement of kinesiological EMG in sport and specific field circumstances, such as the track and/or soccer field, the alpine ski slope, the swimming pool and the ice rink, demands a specific technological and methodological approach, adaptable to both the field and the sport circumstances. Sport movement techniques and skills, training approaches and methods, ergonomic verification of the human-machine interaction have, amongst others, a highly specialized muscular activity in common. The knowledge of such muscular action in all its aspects, its evaluation and its feedback should allow for the optimization of movement, of sports materials, of training possibilities and, in the end, of sports performance. Drawing conclusions from a review of the EMG research of 32 sports, covering over 100 different complex skills, including methodological approaches, is an impossible task. We have attempted to set standards concerning the EMG methodology at the beginning of this review

  7. WAVELET TRANSFORM ANALYSIS OF ELECTROMYOGRAPHY KUNG FU STRIKES DATA

    Directory of Open Access Journals (Sweden)

    Ana Carolina de Miranda Marzullo

    2009-11-01

    Full Text Available In martial arts and contact sports strikes are performed at near maximum speeds. For that reason, electromyography (EMG analysis of such movements is non-trivial. This paper has three main goals: firstly, to investigate the differences in the EMG activity of muscles during strikes performed with and without impacts; secondly, to assess the advantages of using Sum of Significant Power (SSP values instead of root mean square (rms values when analyzing EMG data; and lastly to introduce a new method of calculating median frequency values using wavelet transforms (WMDF. EMG data of the deltoid anterior (DA, triceps brachii (TB and brachioradialis (BR muscles were collected from eight Kung Fu practitioners during strikes performed with and without impacts. SSP results indicated significant higher muscle activity (p = 0.023 for the strikes with impact. WMDF results, on the other hand, indicated significant lower values (p = 0. 007 for the strikes with impact. SSP results presented higher sensitivity than rms to quantify important signal differences and, at the same time, presented lower inter-subject coefficient of variations. The result of increase in SSP values and decrease in WMDF may suggest better synchronization of motor units for the strikes with impact performed by the experienced Kung Fu practitioners

  8. Infrared active thermography for surface layer characterization

    International Nuclear Information System (INIS)

    Semerok, A.; Fomichev, S.; Farcage, D.; Sortais, C.; Courtois, X.

    2006-05-01

    Deposited layer characterization was stated as the main goal of our studies for 2006. The investigations by DRFC/SIPP/GCFP (CEA Cadarache) were performed with the procedure of surface temperature measurements based on infrared thermography with synchronous demodulation (Lock-in Thermography). It was applied to provide the temperature surface monitoring during the modulated heating by illumination. The obtained 2D-cartography revealed the zones with a weak heat transfer resulting from a low layer/surface adhesion or poor layer thermal conductivity. The obtained lock-in cartography data should be regarded only as qualitative. For deposited layers characterization (layer depth, adhesion with the substrate), the active laser pyrometer measurements with the developed experimental device were made in LILM laboratory (CEA Saclay). Active surface pyrometry with repetitive laser heating can provide both qualitative and quantitative data on the first layer and the interface with the substrate. A 3D-numerical model of graphite deposited layer heating by a pulsed high repetition rate laser beam was developed to determine the heated surface temperature with a high temporal and spatial resolution. The theoretical data obtained with 3D-numerical model for surface heating were compared with the experimental results. It was demonstrated that for the given optical and thermo-physical parameters of materials, the theoretical temperatures may be fitted with the experimental results to assess certain unknown parameters of the layer (thermal contact resistance, diffusivity, thickness, porosity, ). Based on the comparison of the obtained experimental and theoretical results, the deposited layer characterization was made. The results of the investigations on Active Laser Pyrometry and Lock-in Thermography demonstrated that the methods can provide qualitative and quantitative data on the deposited layer and on the layer/substrate interface. The correlation and cross-check of the results

  9. Effects of antagonistic co-contraction on differences between electromyography based and optimization based estimates of spinal forces

    NARCIS (Netherlands)

    van Dieen, J.H.; Kingma, I.

    2005-01-01

    Estimates of spinal forces are quite sensitive to model assumptions, especially regarding antagonistic co-contraction. Optimization based models predict co-contraction to be absent, while electromyography (EMG) based models take co-contraction into account, but usually assume equal activation of

  10. Low-power system for the acquisition of the respiratory signal of neonates using diaphragmatic electromyography

    Directory of Open Access Journals (Sweden)

    Torres R

    2017-02-01

    Full Text Available Róbinson Torres,1,2 Sergio López-Isaza,1,2 Elisa Mejía-Mejía,1,2 Viviana Paniagua,1,2 Víctor González3 1Biomedical Engineering Department, Universidad EIA, Envigado, 2Biomedical Engineering Department, Universidad CES, 3Neonathology Department, Hospital General de Medellín Luz Castro de Gutiérrez, Medellín, Antioquia, Colombia Introduction: An apnea episode is defined as the cessation of breathing for ≥15 seconds or as any suspension of breathing accompanied by hypoxia and bradycardia. Obtaining information about the respiratory system in a neonate can be accomplished using electromyography signals from the diaphragm muscle.Objective: The purpose of this paper is to illustrate a method by which the respiratory and electrocardiographic signals from neonates can be obtained using diaphragmatic electromyography.Materials and methods: The system was developed using single-supply, micropower components, which deliver a low-power consumption system appropriate for the development of portable devices. The stages of the system were tested in both adult and neonate patients.Results: The system delivers signals as those expected in both patients and allows the acquisition of respiratory signals directly from the diaphragmatic electromyography.Conclusion: This low-power system may present a good alternative for monitoring the cardiac and respiratory activity in newborn babies, both in the hospital and at home.Significance: The system delivers good signals but needs to be validated for its use in neonates. It is being used in the Neonatal Intensive Care Unit of the Hospital General de Medellín Luz Castro de Gutiérrez. Keywords: apnea, diaphragm, electromyography, neonates, respiratory signal

  11. Low-power system for the acquisition of the respiratory signal of neonates using diaphragmatic electromyography.

    Science.gov (United States)

    Torres, Róbinson; López-Isaza, Sergio; Mejía-Mejía, Elisa; Paniagua, Viviana; González, Víctor

    2017-01-01

    An apnea episode is defined as the cessation of breathing for ≥15 seconds or as any suspension of breathing accompanied by hypoxia and bradycardia. Obtaining information about the respiratory system in a neonate can be accomplished using electromyography signals from the diaphragm muscle. The purpose of this paper is to illustrate a method by which the respiratory and electrocardiographic signals from neonates can be obtained using diaphragmatic electromyography. The system was developed using single-supply, micropower components, which deliver a low-power consumption system appropriate for the development of portable devices. The stages of the system were tested in both adult and neonate patients. The system delivers signals as those expected in both patients and allows the acquisition of respiratory signals directly from the diaphragmatic electromyography. This low-power system may present a good alternative for monitoring the cardiac and respiratory activity in newborn babies, both in the hospital and at home. The system delivers good signals but needs to be validated for its use in neonates. It is being used in the Neonatal Intensive Care Unit of the Hospital General de Medellín Luz Castro de Gutiérrez.

  12. Detection of tonic epileptic seizures based on surface electromyography

    DEFF Research Database (Denmark)

    Larsen, Sigge N.; Conradsen, Isa; Beniczky, Sandor

    2014-01-01

    , median frequency, zero crossing rate and approximate entropy. These features were used as input in the random forest classifier to decide if a data segment was from a seizure or not. The goal was to develop a generic algorithm for all tonic seizures, but better results were achieved when certain...... parameters were adapted specifically for each patient. With patient specific parameters the algorithm obtained a sensitivity of 100% for four of six patients with false detection rates between 0.08 and 7.90 per hour....

  13. Controlling pneumatic artificial muscles in exoskeletons with surface electromyography

    NARCIS (Netherlands)

    Groenhuis, Vincent; Chandrapal, Mervin; Stramigioli, Stefano; Chen, XiaoQi

    2014-01-01

    Powered exoskeletons are gaining more interest in the last few years, as useful devices to provide assistance to elderly and disabled people. Many different types of powered exoskeletons have been studied in the past. In this research paper, a soft lower limb exoskeleton driven by pneumatic

  14. Vitamin D, surface electromyography and physical function in uraemic patients

    DEFF Research Database (Denmark)

    Heaf, J.G.; Mølsted, Stig; Harrison, Adrian Paul

    2010-01-01

    ) under voluntary contractions. Physical function was determined using a 30-second Chair Stand Test and the Short Form 36 quality of life questionnaire. Clinical characteristics were collected from the patient records. Results: Moderate vitamin 25-OHD deficiency (

  15. A comparison of electromyography of gluteus medius and maximus in subjects with and without chronic ankle instability during two functional exercises.

    Science.gov (United States)

    Webster, Kathryn A; Gribble, Phillip A

    2013-02-01

    To determine how gluteus medius (Gmed) and maximus (Gmax) activate during closed-chain functional rehabilitative exercises in those with and without chronic ankle instability (CAI). Cohort study. Subjects performed ten repetitions of a rotational lunge and single-leg rotational squat while surface electromyography was used to collect mean muscle activity of the Gmed and Gmax. Mean electromyography activity of the Gmed and Gmax at maximum excursion was compared between Groups and Exercises using a separate 2-way repeated measures analysis of variance design for each muscle. University biomechanics lab. Nine healthy (8F, 1M) and nine CAI subjects (8F, 1M) RESULTS: For Gmax activation, there was a statistically significant Group by Exercise interaction (F(3,48) = 4.84, p = 0.043). A Scheffe's post-hoc test revealed that during the rotational squat, the CAI group had significantly lower Gmax activation (51.1 ± 31.0%) than the healthy group (78.6 ± 44.8%). There were no statistically significant findings for the Gmed. In the healthy group, the Gmax produced significantly higher activation during rotational squat (78.6 ± 44.8%) compared to the rotational lunge (57.6 ± 31.9%). Because the CAI group had significantly less Gmax activation than the healthy group during the rotational squat at the point of maximum excursion, and because the rotational squat showed significantly higher Gmax activation compared to the rotational lunge, it may be important for clinicians to implement the rotational squat during rehabilitation for those with CAI. Future prospective and intervention research involving hip musculature in those with CAI is recommended. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Classifying Apnea of Prematurity by Transcutaneous Electromyography of the Diaphragm.

    Science.gov (United States)

    Kraaijenga, Juliette V; Hutten, Gerard J; de Waal, Cornelia G; de Jongh, Frans H; Onland, Wes; van Kaam, Anton H

    2018-01-01

    Treatment of apnea is highly dependent on the type of apnea. Chest impedance (CI) has inaccuracies in monitoring respiration, which compromises accurate apnea classification. Electrical activity of the diaphragm measured by transcutaneous electromyography (EMG) is feasible in preterm infants and might improve the accuracy of apnea classification. To compare the accuracy of apnea classification based on diaphragmatic EMG (dEMG) and CI tracings in preterm infants. Fifteen cases of central apnea, 5 of obstructive apnea, and 10 of mixed apnea were selected from recordings containing synchronized continuous tracings of respiratory inductive plethysmography (RIP), airway flow, heart rate (HR), oxygen saturation (SpO2), and breathing activity measured by dEMG and CI. Twenty-two assessors (neonatologists, pediatricians-in-training, and nurses) classified each apnea twice; once based on dEMG, HR, and SpO2 tracings, and once based on CI, HR, and SpO2. The assessors were blinded to the type of respiratory tracing (dEMG or CI) and to the RIP and flow tracings. In total 1,320 assessments were performed, and in 71.1% the apnea was classified correctly. Subgroup analysis based on respiratory tracing showed that 74.8% of the dEMG tracings were classified correctly compared to 67.3% of the CI tracings (p apnea classification based on dEMG was present for central (86.7 vs. 80.3%, p apnea. The improved apnea classification based on dEMG tracing was independent of the type of assessor. Transcutaneous dEMG improves the accuracy of apnea classification when compared to CI in preterm infants, making this technique a promising candidate for future monitoring systems. © 2017 S. Karger AG, Basel.

  17. Does Titan have an Active Surface?

    Science.gov (United States)

    Nelson, R.

    2009-12-01

    ammonia, a compound expected in Titan’s interior. This, combined with the previous evidence from VIMS and RADAR images, creates a strong case for Titan having a presently active surface, possibly due to cryovolcanism. Cassini encountered Titan at very close range on 2008-11-19-13:58 and again on 2008-12-05-12:38. These epochs are called T47 and T48. Comparison of earlier lower resolution data (T5) with the recent T47 and T48 data reveal changes of the surface reflectance and morphology in the Hotei region. This is the first evidence from VIMS that confirms the RADAR report that Hotei Reggio has morphology consistent with volcanic terrain. It has not escaped our attention that ammonia, in association with methane and nitrogen, the principal species of Titan’s atmosphere, closely replicates the environment at the time that live first emerged on earth. If Titan is currently active then these results raise the following questions: What is the full extent of current geologic activity? What are the ongoing processes? Are Titan’s chemical processes today supporting a prebiotic chemistry similar to that under which life evolved on Earth? This work done at JPL under contract with NASA. Refs: [1]R. M. Nelson et al., Icarus 199 (2009) 429-441. [2]R. M. Nelson et al., GRL, VOL. 36, L04202, doi:10.1029/2008GL036206, 2009. [3]S. D. Wall GRL, VOL. 36, L04203, doi:10.1029/2008GL036415, 2009

  18. The surface electromyography analysis of the non-plegic upper limb of hemiplegic subjects Análise da eletromiografia de superfície do membro superior não plégico de hemiplégicos

    Directory of Open Access Journals (Sweden)

    Heloyse U Kuriki

    2010-08-01

    Full Text Available Many authors have studied physical and functional changes in individuals post-stroke, but there are few studies that assess changes in the non-plegic side of hemiplegic subjects. This study aimed to compare the electromyographic activity in the forearm muscles of spastic patients and clinically healthy individuals, to determine if there is difference between the non-plegic side of hemiplegics and the dominant member of normal individuals. 22 hemiplegic subjects and 15 clinically healthy subjects were submitted to electromyography of the flexor and extensor carpi ulnaris muscles during wrist flexion and extension. The flexor muscles activation of stroke group (average 464.6 u.n was significantly higher than the same muscles in control group (mean: 106.3 u.n. during the wrist flexion, what shows that the non affected side does not present activation in the standart of normality found in the control group.Muitos autores estudaram as modificações funcionais e físicas em indivíduos pós-acidente vascular cerebral; porém, poucos estudos avaliam alterações no hemicorpo não plégico de indivíduos hemiplégicos. O objetivo deste estudo foi comparar a atividade eletromiográfica nos músculos do antebraço de pacientes espásticos e indivíduos clinicamente saudáveis, para averiguar se há diferença entre o lado não plégico de indivíduos hemiplégicos e o lado dominante de indivíduos clinicamente saudáveis. 22 indivíduos hemiplégicos e 15 clinicamente saudáveis foram submetidos à eletromiografia dos músculos flexor e extensor ulnar do carpo durante a flexão e extensão do punho. A ativação dos músculos flexores dos hemiplégicos (média: 464,6 u.n, foi significantemente maior que nos indivíduos do grupo controle (média: 106,3 u.n durante o movimento de flexão do punho, o que demonstra que o hemicorpo não acometido dos pacientes estudados não apresenta o comportamento padrão de normalidade encontrado no grupo controle.

  19. Laryngeal Electromyography for Prognosis of Vocal Fold Paralysis.

    Science.gov (United States)

    Pardo-Maza, Adriana; García-Lopez, Isabel; Santiago-Pérez, Susana; Gavilán, Javier

    2017-01-01

    This study aimed to determine the value of laryngeal electromyography in the prognosis of vocal fold paralysis. This is a retrospective descriptive study. This study included 80 patients diagnosed with unilateral or bilateral vocal fold paralysis on flexible laryngoscopy between 2002 and 2014 in a tertiary medical center. Laryngeal electromyography using a standardized protocol was performed; the outcome measures were classified and analyzed into two groups according to the degree of injury. Group 1 included patients with mild to moderate injury, and group 2 included patients with severe to complete injury. Prognosis was correlated with vocal fold motion recovery status with a minimum of 6 months of follow-up since the symptoms onset using positive and negative predictive values. Sixty patients showed acute or chronic recurrent laryngeal neuropathy in laryngeal electromyography. Twelve of 41 patients included in group 1 recovered motion, and 30 of 35 patients included in group 2 did not recover, resulting in 88.2% of positive predictive value and 35.7% of negative predictive value. Our data confirm that laryngeal electromyography is a useful clinical tool in predicting poor recovery in patients with vocal fold paralysis. It allows identification of candidates for early intervention. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  20. Surface and interface electronic structure: Three year activity report

    International Nuclear Information System (INIS)

    Kevan, S.D.

    1992-01-01

    The 3-year activity report covers surface structure and phonon anomalies (surface reconstruction on W(001) and Mo(001), adsorbate lateral ordering, surface Fermi contours and phonon anomalies on Pt(111) and Pd(001)), adsorbate vibrational damping, charge transfer in momentum space: W(011)-K, surface states and resonances (relativistic effects ampersand computations, surface resonances)

  1. Simultaneous Scalp Electroencephalography (EEG), Electromyography (EMG), and Whole-body Segmental Inertial Recording for Multi-modal Neural Decoding

    Science.gov (United States)

    Bulea, Thomas C.; Kilicarslan, Atilla; Ozdemir, Recep; Paloski, William H.; Contreras-Vidal, Jose L.

    2013-01-01

    Recent studies support the involvement of supraspinal networks in control of bipedal human walking. Part of this evidence encompasses studies, including our previous work, demonstrating that gait kinematics and limb coordination during treadmill walking can be inferred from the scalp electroencephalogram (EEG) with reasonably high decoding accuracies. These results provide impetus for development of non-invasive brain-machine-interface (BMI) systems for use in restoration and/or augmentation of gait- a primary goal of rehabilitation research. To date, studies examining EEG decoding of activity during gait have been limited to treadmill walking in a controlled environment. However, to be practically viable a BMI system must be applicable for use in everyday locomotor tasks such as over ground walking and turning. Here, we present a novel protocol for non-invasive collection of brain activity (EEG), muscle activity (electromyography (EMG)), and whole-body kinematic data (head, torso, and limb trajectories) during both treadmill and over ground walking tasks. By collecting these data in the uncontrolled environment insight can be gained regarding the feasibility of decoding unconstrained gait and surface EMG from scalp EEG. PMID:23912203

  2. Differences in the EMG pattern of lea muscle activation during locomotion in Parkinson's disease

    NARCIS (Netherlands)

    Albani, G; Sandrini, G; Kunig, G; Martin-Soelch, C; Mauro, A; Pignatti, R; Pacchetti, C; Dietz, [No Value; Leenders, KL

    2003-01-01

    In this pilot study, EMG patterns of leg muscle activation were studied in five parkinsonian patients with (B1) and five without (B2) freezing. Gastrocnemius medialis (GM) and tibialis anterior (TA) activity was analysed, by means of surface electromyography (EMG), during treadmill walking at two

  3. Influence of hamstring lengthening on muscle activation timing during gait

    NARCIS (Netherlands)

    Buurke, Jaap; Hermens, Hermanus J.; Roetenberg, D.; Harlaar, J.; Rosenbaum, D.; Kleissen, R.F.M.

    2004-01-01

    The purpose of this study was to describe the changes in muscle activation patterns using surface electromyography (sEMG) during walking in patients with cerebral palsy (CP), before and after hamstring lengthening. In the current clinical use of sEMG during walking in CP for pre-operative planning,

  4. Plasma technology of the surface polymer activation

    International Nuclear Information System (INIS)

    Dutra, Jorge C.N.; Mello, Sandra C.; Massi, Marcos; Otani, Choyu; Maciel, Homero S.; Bittencourt, Edison

    2005-01-01

    A number of polymers, especially rubbers, require surface treatment to achieve a satisfactory level of adhesion. The surface of EPDM rubber vulcanized is high hydrophobicity and is not suited for a number of potential applications, in particular, for adhering to the polyurethane liner of solid rocket propellants. In this case, plasma treatment can be a very attractive process because it can efficiently increase the surface energy attributed to surface oxidation with the introduction of polar groups 1, 2. In order to investigate the influence of the parameters on the modifications of the treated surface samples of EPDM rubber by plasma generated by gas oxygen and argon, the water and methylene iodide contact angles were measured at room temperature with an image analyzing using the sessile drop technique 3 - 6 . (author)

  5. Development of practical functional electrical stimulation cycling systems based on an electromyography study of the Cybathlon 2016.

    Science.gov (United States)

    Arnin, Jetsada; Yamsa-Ard, Traisak; Triponyuwasin, Preechapawan; Wongsawat, Yodchanan

    2017-12-05

    The purpose of this study was to develop a functional electrical stimulation (FES) system based on the motor driving concept for use by spinal cord injury patients participating in the FES Cycling competition at the Cybathlon 2016. The proposed FES system consists of a low-power control system, a precise processor unit, and a 4-channel stimulation unit. Self-adhesive carbon conductive electrodes were utilized for stimulation. A 26-year-old SCI patient was qualified to participate in the competition. The pilot patient underwent training for 16 months, which included experience with FES stimulation, performing FES cycling, and reducing spasticity, to practice using the FES system. In addition, using surface electromyography (EMG) during cycling, the muscle activation pattern for generating the stimulation profile was applied and resulted in good performance. The best FES cycling performance the pilot achieved was 1000 meters translation with the cycling system during twelve minutes of using the FES system. The pilot achieved an 1000 meters translation mobility within an average of 16 minutes of cycling. Nevertheless, the system must be further investigated regarding muscle fatigue and other factors that may affect the stimulation conditions.

  6. Sit to stand in elderly fallers vs non-fallers: new insights from force platform and electromyography data.

    Science.gov (United States)

    Chorin, Frédéric; Cornu, Christophe; Beaune, Bruno; Frère, Julien; Rahmani, Abderrahmane

    2016-10-01

    The sit-to-stand movement requires balance control and coordination between the trunk and lower limbs. For these reasons, it is commonly used in clinics for evaluating lower limb muscle function in the elderly. The aim of the present study was to point out re levant biomechanical and neurophysiological sit-to-stand parameters allowing comparison between elderly fallers and non-fallers. Ten elderly fallers and thirty non-fallers performed sit-to-stand movements. Sit-to-stand mechanical (maximal and mean force, impulse) and temporal parameters were measured in the vertical and anteroposterior axes using force platforms. Activity of rectus femoris, vastus lateralis, and gastrocnemius lateralis muscles was bilaterally recorded by surface electromyography. Time to realize sit-to-stand movements was significantly longer in elderly fallers compared to non-fallers (p movement are the most relevant parameters to differentiate fallers and non-fallers. Moreover, these factors highlight different strategies to rise from a chair between faller and non-faller group, suggesting that fallers would constantly adjust their control balance during the sit-to-stand movement.

  7. The Effects of Acupuncture on Peripheral Facial Palsy Sequelae after 20 Years via Electromyography.

    Science.gov (United States)

    Fabrin, Saulo; Soares, Nayara; Regalo, Simone Cecilio Hallak; Verri, Edson Donizetti

    2015-10-01

    This research used electromyography to evaluate the effects of acupuncture on facial palsy peripheral sequelae. The 44-year-old woman who participated in this study presented sequelae resulting from 20 years of peripheral facial nerve palsy (FNP) on the right side and synkinesis in the left eye. In electromyography, the electrodes were positioned on the motor points over the orbicularis oris and the orbicularis oculi muscles to establish myofunctional feedback prior to and after rehabilitation, which consisted of 20-minute sessions of acupuncture once per week for 20 weeks: using manual stimulation at acupoints Yintang, LR3, GB21, CV17, ST2, ST3, ST6, ST7, GB2, and SI19; and Tou-Kuang-Min and ST4 using electrical stimulation with a 4-Hz pulsed current. The subjective pain intensities were recorded. The root-mean-square (RMS) electromyographic comparative analysis showed greater activation and recruitment of muscle fibers on the right side and a reduced overload on the left side, which promoted a functional evolution of movements and a positive response in the stomatognathic system. Acupuncture associated with electrical stimulation reversed the peripheral facial paralysis in a short time. Severe sequelae were minimized due to the balance of muscle activation in response to the electrical stimulation provided by the acupuncture needles. Copyright © 2015. Published by Elsevier B.V.

  8. Surface composition of carburized tungsten trioxide and its catalytic activity

    International Nuclear Information System (INIS)

    Nakazawa, M.; Okamoto, H.

    1985-01-01

    The surface composition and electronic structure of carburized tungsten trioxide are investigated using x-ray photoelectron spectroscopy (XPS). The relationship between the surface composition and the catalytic activity for methanol electro-oxidation is clarified. The tungsten carbide concentration in the surface layer increases with the carburization time. The formation of tungsten carbide enhances the catalytic activity. On the other hand, the presence of free carbon or tungsten trioxide in the surface layer reduces the activity remarkably. It is also shown that, the higher the electronic density of states near the Fermi level, the higher the catalytic activity

  9. Surface activity of thymol: implications for an eventual pharmacological activity.

    Science.gov (United States)

    Sánchez, Mariela E; Turina, Anahí del V; García, Daniel A; Nolan, M Verónica; Perillo, María A

    2004-03-15

    In the present work, we studied the ability of thymol to affect the organization of model membranes and the activity of an intrinsic membrane protein, the GABA(A) receptor (GABA(A)-R). In this last aspect, we tried to elucidate if the action mechanism of this terpene at the molecular level, involves its binding to the receptor protein, changes in the organization of the receptor molecular environment, or both. The self-aggregation of thymol in water with a critical micellar concentration approximately = 4 microM and its ability to penetrate in monomolecular layers of soybean phosphatidylcholine (sPC) at the air-water interface, even at surface pressures above the equilibrium, lateral pressure of natural bilayers were demonstrated. Thymol affected the self-aggregation of Triton X-100 and the topology of sPC vesicles. It also increased the polarity of the membrane environment sensed by the electrochromic dye merocyanine. A dipolar moment of 1.341 Debye was calculated from its energy-minimized structure. Its effect on the binding of [3H]-flunitrazepam ([3H]-FNZ) to chick brain synaptosomal membranes changed qualitatively from a tendency to the inhibition to a clear activatory regime, up on changing the phase state of the terpene (from a monomeric to a self-aggregated state). Above its CMC, thymol increased the affinity of the binding of [3H]-FNZ (K(d-control)= 2.9, K(d-thymol)= 1.7 nM) without changing the receptor density (B(max-control)= 910, B(max-thymol)= 895 fmol/mg protein). The activatory effect of thymol on the binding of [ [3H]-FNZ was observed even in the presence of the allosteric activator gamma-aminobutyric acid (GABA) at a concentration of maximal activity, and was blocked by the GABA antagonist bicuculline. Changes in the dipolar arrangement and in the molecular packing of GABA(A)-R environment are discussed as possible mediators of the action mechanism of thymol.

  10. Assessment of a wearable force- and electromyography device and comparison of the related signals for myocontrol

    Directory of Open Access Journals (Sweden)

    Mathilde Connan

    2016-11-01

    Full Text Available In the frame of assistive robotics, multi-finger prosthetic hand/wrists have recently appeared,offering an increasing level of dexterity; however, in practice their control is limited to a few handgrips and still unreliable, with the effect that pattern recognition has not yet appeared in the clinicalenvironment. According to the scientific community, one of the keys to improve the situation ismulti-modal sensing, i.e., using diverse sensor modalities to interpret the subject’s intent andimprove the reliability and safety of the control system in daily life activities. In this work, wefirst describe and test a novel wireless, wearable force- and electromyography device; throughan experiment conducted on ten intact subjects, we then compare the obtained signals bothqualitatively and quantitatively, highlighting their advantages and disadvantages. Our resultsindicate that force-myography yields signals which are more stable across time during whenevera pattern is held, than those obtained by electromyography. We speculate that fusion of the twomodalities might be advantageous to improve the reliability of myocontrol in the near future.

  11. Sperm cell surface dynamics during activation and fertilization

    NARCIS (Netherlands)

    Boerke, A.|info:eu-repo/dai/nl/304822922

    2013-01-01

    Before the sperm cell can reach the oocyte it needs to be activated and to undergo a series of preparative steps. The sperm surface dynamics was studied in relation to this activation process and the modifications and removal of sperm surface components havebeen investigated. Bicarbonate-induced

  12. Temperature effects on surface activity and application in oxidation ...

    Indian Academy of Sciences (India)

    Keywords. Surface activity; cetyl trimethylammonium bromide; sodium dodecyl sulfate; temperature; oxidation. ... Catalytic effect on oxidation of toluene derivatives with potassium permanganate follows the order CTAB-SDS > SDS > CTAB. This is not caused by the dissociative effect of CTAB-SDS with low surface activity at ...

  13. Coordinated surface activities in Variovorax paradoxus EPS

    Directory of Open Access Journals (Sweden)

    Gregory Glenn A

    2009-06-01

    Full Text Available Abstract Background Variovorax paradoxus is an aerobic soil bacterium frequently associated with important biodegradative processes in nature. Our group has cultivated a mucoid strain of Variovorax paradoxus for study as a model of bacterial development and response to environmental conditions. Colonies of this organism vary widely in appearance depending on agar plate type. Results Surface motility was observed on minimal defined agar plates with 0.5% agarose, similar in nature to swarming motility identified in Pseudomonas aeruginosa PAO1. We examined this motility under several culture conditions, including inhibition of flagellar motility using Congo Red. We demonstrated that the presence of a wetting agent, mineral, and nutrient content of the media altered the swarming phenotype. We also demonstrated that the wetting agent reduces the surface tension of the agar. We were able to directly observe the presence of the wetting agent in the presence and absence of Congo Red, and found that incubation in a humidified chamber inhibited the production of wetting agent, and also slowed the progression of the swarming colony. We observed that swarming was related to both carbon and nitrogen sources, as well as mineral salts base. The phosphate concentration of the mineral base was critical for growth and swarming on glucose, but not succinate. Swarming on other carbon sources was generally only observed using M9 salts mineral base. Rapid swarming was observed on malic acid, d-sorbitol, casamino acids, and succinate. Swarming at a lower but still detectable rate was observed on glucose and sucrose, with weak swarming on maltose. Nitrogen source tests using succinate as carbon source demonstrated two distinct forms of swarming, with very different macroscopic swarm characteristics. Rapid swarming was observed when ammonium ion was provided as nitrogen source, as well as when histidine, tryptophan, or glycine was provided. Slower swarming was observed

  14. Towards the control of an active hand orthosis for people with Duchenne muscular dystrophy : Design and Validation of a wireless sEMG sleeve

    NARCIS (Netherlands)

    Nizamis, Kostas; Ganseij, Maarten; Koopman, H.F.J.M.

    2017-01-01

    Duchenne Muscular Dystrophy (DMD) is a progressive muscular disease. Active hand orthoses can greatly improve the quality of life of people with DMD. Surface Electromyography (sEMG) is commonly used for the control of active devices. The interfacing between the human and the sensor is regularly done

  15. TOWARDS THE CONTROL OF AN ACTIVE HAND ORTHOSIS FOR PEOPLE WITH DUCHENNE MUSCULAR DYSTROPHY: DESIGN AND VALIDATION OF A WIRELESS SEMG SLEEVE

    NARCIS (Netherlands)

    Nizamis, Kostas; Ganseij, Maarten; Koopman, Hubertus F.J.M.

    2017-01-01

    Duchenne Muscular Dystrophy (DMD) is a progressive muscular disease. Active hand orthoses can greatly improve the quality of life of people with DMD. Surface Electromyography (sEMG) is commonly used for the control of active devices. The interfacing between the human and the sensor is regularly done

  16. Muscle activation during selected strength exercises in women with chronic neck muscle pain

    DEFF Research Database (Denmark)

    Andersen, L.L.; Kjaer, M.; Andersen, C.H.

    2008-01-01

    Background and Purpose. Muscle-specific strength training has previously been shown to be effective in the rehabilitation of chronic neck muscle pain in women. The aim of this stud), was to determine the level of activation of the neck and shoulder muscles using surface electromyography (EMG) (lu...

  17. Scapular muscle activity from selected strengthening exercises performed at low and high intensity

    DEFF Research Database (Denmark)

    Andersen, Christoffer H; Zebis, Mette K; Saervoll, Charlotte

    2012-01-01

    for proper exercise prescription. This study determines scapular muscle activity during strengthening exercises for scapular muscles performed at low and high intensities (Borg-CR10 level 3 and 8). Surface electromyography (EMG) from selected scapular muscles was recorded during seven strengthening exercises...

  18. Deglutição de respiradores orais e nasais: avaliação clínica fonoaudiológica e eletromiográfica Swallowing of oral and nose breathers: speech-language and electromyography assessment

    Directory of Open Access Journals (Sweden)

    Tais Regina Hennig

    2009-12-01

    Full Text Available OBJETIVO: avaliar e comparar a deglutição de sujeitos respiradores orais e nasais, por meio da avaliação clínica e eletromiográfica dos músculos orbiculares orais, superior e inferior. MÉTODOS: participaram deste estudo 16 sujeitos na faixa etária de 6:8 a 10:10 distribuídos em dois grupos, um de respiradores orais e outro de respiradores nasais. Foram submetidos à avaliação clínica fonoaudiológica e eletromiográfica de superfície. O exame fonoaudiológico contemplou as estruturas e funções do sistema estomatognático, e a avaliação eletromiográfica consistiu na captação da atividade elétrica dos músculos orbiculares orais, superior e inferior, durante as situações de isometria e de deglutição. Da avaliação clínica consideraram-se somente os resultados referentes à deglutição, observando-se a presença de ação labial e mentual, e de projeção lingual, as quais foram analisados de forma descritiva. Para análise estatística dos dados eletromiográficos, utilizou-se o Teste t para comparação entre os grupos. A significância adotada foi de 5% (p PURPOSE: to evaluate and compare the swallowing of mouth and nose breathers through of speech-language and electromyography evaluation concerning the orbicularis oris muscles, and lower and upper lips. METHODS: 16 subjects aged 6:8 - 10:10 and divided on two groups participated in this study, one with mouth and another one with nose breathers. Both groups were submitted to clinical and surface electromyography evaluation. The speech-language evaluation contemplated the exam of the structures and functions of the stomatognathic system. The electromyography evaluation consisted of the captivation of the electrical activity at the orbicularis oris muscles, and lower and upper lips, during isometry and swallowing situations. In the clinical results were considered only the swallowing variables. Therefore, our study could observe the presence of labial and mentalis

  19. Effect of age on human-computer-interface control via neck electromyography.

    Science.gov (United States)

    Hands, Gabrielle L; Stepp, Cara E

    2016-01-01

    The purpose of this study was to determine the effect of age on visuomotor tracking using submental and anterior neck surface electromyography (sEMG) to assess feasibility of computer control via neck musculature, which allows people with little remaining motor function to interact with computers. Thirty-two healthy adults participated: sixteen younger adults aged 18 - 29 years and sixteen older adults aged 69 - 85 years. Participants modulated sEMG to achieve targets presented at different amplitudes using real-time visual feedback. Root-mean-squared (RMS) error was used to quantify tracking performance. RMS error was increased for older adults relative to younger adults. Older adults demonstrated more RMS error than younger adults as a function of increasing target amplitude. The differential effects of age found on static tracking performance in anterior neck musculature suggest more difficult translation of human-computer-interfaces controlled using anterior neck musculature for static tasks to older populations.

  20. Experiences in the creation of an electromyography database to help hand amputated persons.

    Science.gov (United States)

    Atzori, Manfredo; Gijsberts, Arjan; Heynen, Simone; Hager, Anne-Gabrielle Mittaz; Castellimi, Claudio; Caputo, Barbara; Müller, Henning

    2012-01-01

    Currently, trans-radial amputees can only perform a few simple movements with prosthetic hands. This is mainly due to low control capabilities and the long training time that is required to learn controlling them with surface electromyography (sEMG). This is in contrast with recent advances in mechatronics, thanks to which mechanical hands have multiple degrees of freedom and in some cases force control. To help improve the situation, we are building the NinaPro (Non-Invasive Adaptive Prosthetics) database, a database of about 50 hand and wrist movements recorded from several healthy and currently very few amputated persons that will help the community to test and improve sEMG-based natural control systems for prosthetic hands. In this paper we describe the experimental experiences and practical aspects related to the data acquisition.

  1. Active Surface Compensation for Large Radio Telescope Antennas

    Science.gov (United States)

    Wang, Congsi; Li, Haihua; Ying, Kang; Xu, Qian; Wang, Na; Duan, Baoyan; Gao, Wei; Xiao, Lan; Duan, Yuhu

    2018-03-01

    With the development of radio telescope antennas with large apertures, high gain, and wide frequency bands, compensation methods, such as mechanical or electronic compensation, are obviously essential to ensure the electrical performance of antennas that work in complex environments. Since traditional compensation methods can only adjust antenna pointing but not the surface accuracy, which are limited for obtaining high surface precision and aperture efficiency, active surface adjustment has become an indispensable tool in this field. Therefore, the development process of electrical performance compensation methods for radio telescope antennas is introduced. Further, a series of analyses of the five key technologies of active surface adjustment is presented. Then, four typical large antennas that have been designed with active main reflector technology are presented and compared. Finally, future research directions and suggestions for reflector antenna compensation method! s based on active surface adjustment are presented.

  2. Surface enhanced Raman optical activity (SEROA)

    DEFF Research Database (Denmark)

    Abdali, Salim; Blanch, E.W.

    2008-01-01

    Raman optical activity (ROA) directly monitors the stereochemistry of chiral molecules and is now an incisive probe of biomolecular structure. ROA spectra contain a wealth of information on tertiary folding, secondary structure and even the orientation of individual residues in proteins and nucleic...

  3. Reconstructing four joint angles on the shoulder and elbow from noninvasive electroencephalographic signals through electromyography

    Directory of Open Access Journals (Sweden)

    Kyuwan eChoi

    2013-10-01

    Full Text Available In this study, first the cortical activities over 2240 vertexes on the brain were estimated from 64 channels electroencephalography (EEG signals using the Hierarchical Bayesian estimation while 5 subjects did continuous arm reaching movements. From the estimated cortical activities, a sparse linear regression method selected only useful features in reconstructing the electromyography (EMG signals and estimated the EMG signals of 9 arm muscles. Then, a modular artificial neural network was used to estimate four joint angles from the estimated EMG signals of 9 muscles: one for movement control and the other for posture control. The estimated joint angles using this method have the correlation coefficient of 0.807 (±0.10 and the normalized root-mean-square error (nRMSE of 0.176 (±0.29 with the actual joint angles.

  4. Acid-base characteristics of powdered-activated-carbon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Reed, B.E. (West Virginia Univ., Morgantown (United States)); Jensen, J.N.; Matsumoto, M.R. (State Univ. of New York, Buffalo (United States))

    Adsorption of heavy metals onto activated carbon has been described using the surface-complex-formation (SCF) model, a chemical equilibrium model. The SCF model requires a knowledge of the amphoteric nature of activated carbon prior to metal adsorption modeling. In the past, a single-diprotic-acid-site model had been employed to describe the amphoteric nature of activated-carbon surfaces. During this study, the amphoteric nature of two powdered activated carbons were investigated, and a three-monoprotic site surface model was found to be a plausible alternative. The single-diprotic-acid-site and two-monoprotic-site models did not describe the acid-base behavior of the two carbons studied adequately. The two-diprotic site was acceptable for only one of the study carbons. The acid-base behavior of activated carbon surfaces seem to be best modeled as a series of weak monoprotic acids.

  5. Surface coverage dictates the surface bio-activity of D-amino acid oxidase.

    Science.gov (United States)

    Herrera, Elisa; Giacomelli, Carla E

    2014-05-01

    This work presents a systematic study on the relationship between the adsorption mechanism and the surface bio-activity of D-amino acid oxidase (pkDAAO). This rational approach is based on measuring the characteristic filling and relaxation times under different experimental conditions. With such a goal, real-time adsorption-desorption experiments at different degrees of surface coverage were performed tuning the electrostatic and hydrophobic interactions by changing the pH condition for the adsorption and the substrate properties (silica or gold). Surface bio-activity was measured in situ by amperometry using the bio-functional surface as the working electrode and ex situ by spectrophotometry. On both solid substrates, pkDAAO adsorption is a transport-controlled process, even under unfavorable electrostatic interactions (charged protein and substrate with the same sign) due to the high percentage of basic amino acids in the enzyme. On silica, the relaxation step is electrostatic in nature and occurs in the same time-scale as filling the surface when the substrate and the enzyme are oppositely charged at low surface coverage. Under unfavorable electrostatic conditions, the relaxation (if any) occurs at long time. Accordingly, the bio-activity of the native pkDAAO is preserved at any surface coverage. On gold, this step is driven by hydrophobic interactions (pH-independent) and the surface bio-activity is highly dependent on the degree of surface coverage. Under these conditions, the surface bio-activity is preserved only at high surfaces coverage. Our results clearly indicate that pkDAAO bio-functionalized surfaces cannot be coupled to amperometry because the analyte interferes the electrochemical signal. However, this simple bio-functionalized strategy can be joined to other detection methods. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Fibroblast adhesion and activation onto micro-machined titanium surfaces.

    Science.gov (United States)

    Guillem-Marti, J; Delgado, L; Godoy-Gallardo, M; Pegueroles, M; Herrero, M; Gil, F J

    2013-07-01

    Surface modifications performed at the neck of dental implants, in the manner of micro-grooved surfaces, can reduce fibrous tissue encapsulation and prevent bacterial colonization, thereby improving fibrointegration and the formation of a biological seal. However, the applied procedures are technically complex and/or time consuming methods. The aim of this study was to analyse the fibroblast behaviour on modified titanium surfaces obtained, applying a simple and low-cost method. An array of titanium surfaces was obtained using a commercial computerized numerical control lathe, modifying the feed rate and the cutting depth. To elucidate the potential ability of the generated surfaces to activate connective tissue cells, a thorough gene (by real time - qPCR) and protein (by western blot or zymography) expression and cellular response characterization (cell morphology, cell adhesion and cell activation by secreting extracellular matrix (ECM) components and their enzyme regulators) was performed. Micro-grooved surfaces have statistically significant differences in the groove's width (approximately 10, 50 and 100 μm) depending on the applied advancing fixed speed. Field emission scanning electron microscopy images showed that fibroblasts oriented along the generated grooves, but they were only entirely accommodated on the wider grooves (≥50 μm). Micro-grooved surfaces exhibited an earlier cell attachment and activation, as seen by collagen Iα1 and fibronectin deposition and activation of ECM remodelling enzymes, compared with the other surfaces. However, fibroblasts could remain in an activated state on narrower surfaces (micro-grooved surfaces could improve implant integration at the gingival site with respect to polished surfaces. Micro-grooved surfaces enhance early fibroblast adhesion and activation, which could be critical for the formation of a biological seal and finally promote tissue integration. Surfaces with wider grooves (≥50 μm) seem to be more

  7. Deep learning with convolutional neural networks: a resource for the control of robotic prosthetic hands via electromyography

    Directory of Open Access Journals (Sweden)

    Manfredo Atzori

    2016-09-01

    Full Text Available Motivation: Natural control methods based on surface electromyography and pattern recognition are promising for hand prosthetics. However, the control robustness offered by scientific research is still not sufficient for many real life applications and commercial prostheses are in the best case capable to offer natural control for only a few movements. Objective: In recent years deep learning revolutionized several fields of machine learning, including computer vision and speech recognition. Our objective is to test its capabilities for the natural control of robotic hands via surface electromyography by providing a baseline on a large number of intact and amputated subjects. Methods: We tested convolutional networks for the classification of an average of 50 hand movements in 67 intact subjects and 11 hand amputated subjects. The simple architecture of the neural network allowed to make several tests in order to evaluate the effect of pre-processing, layer architecture, data augmentation and optimization. The classification results are compared with a set of classical classification methods applied on the same datasets.Results: The classification accuracy obtained with convolutional neural networks using the proposed architecture is higher than the average results obtained with the classical classification methods but lower than the results obtained with the best reference methods in our tests. Significance: The results show that convolutional neural networks with a very simple architecture can produce accuracy comparable to the average classical classification methods. They show that several factors (including pre-processing, the architecture of the net and the optimization parameters can be fundamental for the analysis of surface electromyography data. Finally, the results suggest that deeper and more complex networks may increase dexterous control robustness, thus contributing to bridge the gap between the market and scientific research

  8. Lower limb muscle activity during squat and judo technique seoi nage

    OpenAIRE

    Holý, Jakub

    2015-01-01

    Title: Lower limb muscle activity during squat and technique seoi nage in judo Objectives: Goals of my work is finding activity lower muscle limb using surface electromyography in shallow squat, deep squat and seoi nage technic in judo. From the obtained results will be compared muscle activity in relative to MVC and compared timing activity of measuring muscles between deep squat and technic seoi nage right. Methods: Research component consisted of 10 subjects, 5 of fitness and 5 are active ...

  9. Surface activity of Acinetobacter calcoaceticus sp. 2CA2

    Energy Technology Data Exchange (ETDEWEB)

    Neufeld, R.J.; Zajic, J.E.

    1984-01-01

    The hydrocarbon metabolizing Acinetobacter calcoaceticus sp. 2CA2 reduces the surface tension of the culture broth during growth on liquid hydrocarbons. This activity, which is not evident during growth on soluble substrates, is associated with the whole cells. Removing the cells from the culture broth increases the surface tension of the liquid phase. The cells when resuspended in water result in a dramatic lowering of the surface tension. Acinetobacter sp. 2CA2 tends to partition between the two liquid phases during growth on hydrocarbons. Both the hydrocarbon bound and nonadhering cells are equally surface active. The whole cells are also able to form and stabilize kerosene-water emulsions. This ability is not related to the lowering of the liquid surface or interfacial tension, since both surface active and nonsurface active cells demonstrated the same emulsifying properties. An extracellular lipopeptide produced during growth on hydrocarbons is not surface active but effectively forms and stabilizes kerosene-water emulsions. The cells and extracellular lipopeptide are also effective in de-emulsifying surfactant stabilized test emulsions. The cells and extracellular lipopeptide are also effective in de-emulsifying surfactant stabilized test emulsions. The lipopeptide product reduced the half-life of a Tween-Span (TS) stabilized kerosene-water emulsion from 650 to 0.4 h at product concentrations of less than 1% (w/v).

  10. Reliability of surface EMG as an assessment tool for trunk activity and potential to determine neurorecovery in SCI.

    Science.gov (United States)

    Mitchell, M D; Yarossi, M B; Pierce, D N; Garbarini, E L; Forrest, G F

    2015-05-01

    Reliability and validity study. This study investigates the responsiveness and reliability of the brain motor control assessment (BMCA) as a standardized neurophysiological assessment tool to: (i) characterize trunk neural activity in neurologically-intact controls; (ii) measure and quantify neurorecovery of trunk after spinal cord injury (SCI). Kessler Foundation Research Center, West Orange, NJ. A standardized BMCA protocol was performed to measure surface electromyography (sEMG) recordings for seven bilateral trunk muscles on 15 able-bodied controls during six maneuvers (inhalation, exhalation, neck flexion, jendrassik, unilateral grip). Additionally, sEMG recordings were analyzed for one chronic SCI individual before electrical stimulation (ES), after ES of the lower extremities while supine, and after active stand training using body-weight support with bilateral ES. sEMG recordings were collected on bilateral erector spinae, internal and external obliques, upper and middle trapezius, biceps and triceps. For each maneuver a voluntary response index was calculated: incorporating the magnitude of sEMG signal and a similarity index (SI), which quantifies the distribution of activity across all muscles. Among all maneuvers, the SI presented reproducible assessment of trunk-motor function within (ICC: 0.860-0.997) and among (P⩾0.22) able-bodied individuals. In addition, potential changes were measured in a chronic SCI individual after undergoing two intensive ES protocols. The BMCA provides reproducible characterization of trunk activity in able-bodied individuals, lending credence for its use in neurophysiological assessment of motor control. Additionally, the BMCA as an assessment tool to measure neurorecovery in an individual with chronic SCI after intense ES interventions was demonstrated.

  11. Comparative study of a muscle stiffness sensor and electromyography and mechanomyography under fatigue conditions.

    Science.gov (United States)

    Han, Hyonyoung; Jo, Sungho; Kim, Jung

    2015-07-01

    This paper proposes the feasibility of a stiffness measurement for muscle contraction force estimation under muscle fatigue conditions. Bioelectric signals have been widely studied for the estimation of the contraction force for physical human-robot interactions, but the correlation between the biosignal and actual motion is decreased under fatigue conditions. Muscle stiffness could be a useful contraction force estimator under fatigue conditions because it measures the same physical quantity as the muscle contraction that generates the force. Electromyography (EMG), mechanomyography (MMG), and a piezoelectric resonance-based active muscle stiffness sensor were used to analyze the biceps brachii under isometric muscle fatigue conditions with reference force sensors at the end of the joint. Compared to EMG and MMG, the change in the stiffness signal was smaller (p fatigue condition changed fatigue conditions. This result indicates that the muscle stiffness signal is less sensitive to muscle fatigue than other biosignals. This investigation provides insights into methods of monitoring and compensating for muscle fatigue.

  12. Laser activation of diamond surface for electroless metal plating

    Science.gov (United States)

    Pimenov, S. M.; Shafeev, G. A.; Laptev, V. A.; Loubnin, E. N.

    1994-04-01

    Selective area electroless nickel and copper deposition onto the surface of diamond single crystals and polycrystalline diamond films has been realized. Three methods of laser-assisted activation of diamond surface were applied: (i) prenucleation of diamond surface with a thin layer of palladium catalyst via laser-induced decomposition of a palladium acetyl-acetonate [Pd(acac)2] solid film; (ii) deposition of palladium by means of the decomposition of Pd(acac)2 dissolved in dimethylformamide; (iii) laser-induced damage of diamond surface.

  13. The potential and limitations of quantitative electromyography in equine medicine.

    Science.gov (United States)

    Wijnberg, Inge D; Franssen, Hessel

    2016-03-01

    This review discusses the scope of using (quantitative) electromyography (EMG) in diagnosing myopathies and neuropathies in equine patients. In human medicine, many EMG methods are available for the diagnosis, pathophysiological description and evaluation, monitoring, or rehabilitation of patients, and some of these techniques have also been applied to horses. EMG results are usually combined with other neurophysiological data, ultrasound, histochemistry, biochemistry of muscle biopsies, and clinical signs in order to provide a complete picture of the condition and its clinical course. EMG technology is commonly used in human medicine and has been subject to constant development and refinement since its introduction in 1929, but the usefulness of the technique in equine medicine is not yet widely acknowledged. The possibilities and limitations of some EMG applications for equine use are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Sleep/wake estimation using only anterior tibialis electromyography data

    Directory of Open Access Journals (Sweden)

    Hwang SuHwan

    2012-05-01

    Full Text Available Abstract Background In sleep efficiency monitoring system, actigraphy is the simplest and most commonly used device. However, low specificity to wakefulness of actigraphy was revealed in previous studies. In this study, we assumed that sleep/wake estimation using actigraphy and electromyography (EMG signals would show different patterns. Furthermore, each EMG pattern in two states (sleep, wake during sleep was analysed. Finally, we proposed two types of method for the estimation of sleep/wake patterns using only EMG signals from anterior tibialis muscles and the results were compared with PSG data. Methods Seven healthy subjects and five patients (2 obstructive sleep apnea, 3 periodic limb movement disorder participated in this study. Night time polysomnography (PSG recordings were conducted, and electrooculogram, EMG, electroencephalogram, electrocardiogram, and respiration data were collected. Time domain analysis and frequency domain analysis were applied to estimate the sleep/wake patterns. Each method was based on changes in amplitude or spectrum (total power of anterior tibialis electromyography signals during the transition from the sleep state to the wake state. To obtain the results, leave-one-out-cross-validation technique was adopted. Results Total sleep time of the each group was about 8 hours. For healthy subjects, the mean epoch-by-epoch results between time domain analysis and PSG data were 99%, 71%, 80% and 0.64 (sensitivity, specificity, accuracy and kappa value, respectively. For frequency domain analysis, the corresponding values were 99%, 73%, 81% and 0.67, respectively. Absolute and relative differences between sleep efficiency index from PSG and our methods were 0.8 and 0.8% (for frequency domain analysis. In patients with sleep-related disorder, our proposed methods revealed the substantial agreement (kappa > 0.61 for OSA patients and moderate or fair agreement for PLMD patients. Conclusions The results of our proposed

  15. Surface-activated joining method for surveillance coupon reconstitution

    International Nuclear Information System (INIS)

    Kaihara, Shoichiro; Nakamura, Terumi

    1993-01-01

    As nuclear power plants approach the end of their license periods and license renewal is contemplated, there is an increasing need to expand the data base of mechanical properties obtainable from archival surveillance specimens. A new joining method for reconstituting broken Charpy specimens is being developed, the objective being to retain the original properties of the material in the process. The new method is called surface-activated joining (SAJ). It is designed to obtain a good junction without applying extra heating and deformation. In particular, the purpose of SAJ is to minimize the width of the heat-affected zone (HAZ) and to decrease the maximum temperature experienced by the specimen during reconsolidation of the two pieces. Generally, machined metal surfaces are contaminated with films of oxide, adsorbed gas, oil, or other vapors that impede bonding of surfaces during joining. However, if surface contamination is removed and the two surfaces are mated as closely as possible, joining can be achieved at low temperatures and modest stress levels. In order to apply the SAJ method, the following requirements must be met: (1) inert atmosphere to protect the surfaces from atmospheric gases and oxidation; (2) removal of the existing contamination layers to activate the surfaces; and (3) method for bringing the two surfaces into very intimate contact prior to joining

  16. Surface activity, lipid profiles and their implications in cervical cancer.

    Directory of Open Access Journals (Sweden)

    Preetha A

    2005-01-01

    Full Text Available Background: The profiles of lipids in normal and cancerous tissues may differ revealing information about cancer development and progression. Lipids being surface active, changes in lipid profiles can manifest as altered surface activity profiles. Langmuir monolayers offer a convenient model for evaluating surface activity of biological membranes. Aims: The aims of this study were to quantify phospholipids and their effects on surface activity of normal and cancerous human cervical tissues as well as to evaluate the role of phosphatidylcholine (PC and sphingomyelin (SM in cervical cancer using Langmuir monolayers. Methods and Materials: Lipid quantification was done using thin layer chromatography and phosphorus assay. Surface activity was evaluated using Langmuir monolayers. Monolayers were formed on the surface of deionized water by spreading tissue organic phase corresponding to 1 mg of tissue and studying their surface pressure-area isotherms at body temperature. The PC and SM contents of cancerous human cervical tissues were higher than those of the normal human cervical tissues. Role of PC and SM were evaluated by adding varying amounts of these lipids to normal cervical pooled organic phase. Statistical analysis: Student′s t-test (p < 0.05 and one-way analysis of variance (ANOVA was used. Results: Our results reveals that the phosphatidylglycerol level in cancerous cervical tissue was nearly five folds higher than that in normal cervical tissue. Also PC and sphingomyelin SM were found to be the major phospholipid components in cancerous and normal cervical tissues respectively. The addition of either 1.5 µg DPPC or 0.5 µg SM /mg of tissue to the normal organic phase changed its surface activity profile to that of the cancerous tissues. Statistically significant surface activity parameters showed that PC and SM have remarkable roles in shifting the normal cervical lipophilic surface activity towards that of cancerous lipophilic

  17. HLA-F is a surface marker on activated lymphocytes.

    Science.gov (United States)

    Lee, Ni; Ishitani, Akiko; Geraghty, Daniel E

    2010-08-01

    Of the three nonclassical class I antigens expressed in humans, HLA-F has been least characterized with regard to expression or function. In this study, we examined HLA-F expression focusing on lymphoid cells, where our previous work with homologous cell lines had demonstrated surface HLA-F expression. HLA-F protein expression was observed by Western blot analysis in all resting lymphocytes, including B cells, T cells, NK cells, and monocytes, all of which lacked surface expression in the resting state. Upon activation, using a variety of methods to activate different lymphocyte subpopulations, all cell types that expressed HLA-F intracellularly showed an induction of surface HLA-F protein. An examination of peripheral blood from individuals genetically deficient for TAP and tapasin expression demonstrated the same activation expression profiles for HLA-F,but with altered kinetics post-activation. Further analysis of CD41+CD25+1 Treg showed that HLA-F was not upregulated on the major fraction of these cells when they were activated,whereas CD41+CD25- T cells showed strong expression of surface HLA-F when activated under identical conditions. These findings are discussed with regard to possible functions for HLA-F and its potential clinical use as a marker of an activated immune response.

  18. Synthesis and surface active properties of cationic surface active agents from crude rice bran oil

    Directory of Open Access Journals (Sweden)

    El-Dougdoug, W. I. A.

    1999-10-01

    Full Text Available Cationic surfactants of 2-hidroxy-3-(2- alkylamidopolyethyl amino propane-1-triethylammonium hydroxides (ix-xuia-d were prepared from fatty acids (ia-d [palmitic, stearic, oleic, linoleic acid] and mixed fatty acids of crude rice bran oil ie [RBO]. The reaction of these acids with ethylenediamine, diethylenetriamine, triethylenetetramine andletraethylenepentamine (iia-d produced (iii-viia-d. The produced amidopolyethylamine (iii-viia-d reacted with 2-epoxypropylenetriethylammonium chloride (viii to give the cationic surfactants (ix-xiiia-d . The produced derivatives were purified and characterized by microanalysis, molecular weight determination, infra-red (IR, and proton nuclear magnetic resonance (1H NMR spectra. The surface active properties and inhibition efficiency of the prepared cationic surfactants were determined.

    Se han preparado tensioactivos catiónicos de hidróxidos de! 2-hidroxi-3-(2-alquilamidopolietilamino propano-1;trietilamonio (ix-xiiia-d a partir de los ácidos grasos (ia-d [ácido palmítico, esteárico, oleico y linoleico] y mezclas de ácidos grasos de aceite de germen de arroz crudo ie [RBO]. La reacción de estos ácidos con etilenodiamina, dietilenotriamina, trietilenotetramina y tetraetilenopentamina (iia-d produjo los compuestos (iv-viia-d . Los amidopolietilaminos producidos (iii-viia-d reaccionaron con el cloruro de 2-epoxipropilenotrietilamonio (viii para dar los tensioactivos catiónicos (ix-xiiia-d. Los derivados producidos se purificaron y caracterizaron por microanálisis, determinación del peso molecular, espectros de infrarrojo (IR y resonancia magnética nuclear de protón (1H NMR. Se determinaron las propiedades tensioactivas y la eficacia de inhibición de los tensioactivos cati

  19. Mechanochemical activation and gallium and indiaarsenides surface catalycity

    Science.gov (United States)

    Kirovskaya, I. A.; Mironova, E. V.; Umansky, I. V.; Brueva, O. Yu; Murashova, A. O.; Yureva, A. V.

    2018-01-01

    The present work has been carried out in terms of determining the possibilities for a clearer identification of the active sites nature, intermediate surface compounds nature, functional groups during adsorption and catalysis, activation of the diamond-like semiconductors surface (in particular, the AIIIBV type) based on mechanochemical studies of the “reaction medium (H2O, iso-C3H7OH) - dispersible semiconductor (GaAs, InAs)” systems. As a result, according to the read kinetic curves of dispersion in water, both acidification and alkalinization of the medium have been established and explained; increased activity of the newly formed surface has been noted; intermediate surface compounds, functional groups appearing on the real surface and under H2O adsorption conditions, adsorption and catalytic decomposition of iso-C3H7OH have been found (with explanation of the origin). The unconcealed role of coordinatively unsaturated atoms as active sites of these processes has been shown; the relative catalytic activity of the semiconductors studied has been evaluated. Practical recommendations on the preferred use of gallium arsenide in semiconductor gas analysis and semiconductor catalysis have been given in literature searches, great care should be taken in constructing both.

  20. Atomic and molecular layer activation of dielectric surfaces

    Science.gov (United States)

    Senkevich, John Joseph

    Strong interaction between the material deposit and substrate is critical to stable deposits and interfaces. The work presented here focuses on the surface activation of dielectric surfaces and oxidized metal surfaces to promote the chemisorption of palladium (II) hexafluoroacetylacetonate (PdII (hfac)2). The goal is to develop reliable, robust metallization protocols, which enable strong interactions between the metal and substrate. SiO2, air exposed Ta, Trikon, and SiLK were activated with sulfur or phosphorus. Two types of activations were developed; one based on self-assembled chemistry, and the other a plasma-assisted process. Activation of the surface using self-assembly techniques was carried out using mercaptan-terminated silane and tetrasulfide silane. The resulting films were characterized by variable angle spectroscopic ellipsometry, contact angle goniometry, and X-ray photoelectron spectroscopy. Tetrasulfide silane sources films exhibit self-limiting behavior, even in the presence of water vapor; whereas mercaptan-terminated silane sourced films tend to be thicker. The surface activations using atomic layers of sulfur and phosphorus were carried out in a rf plasma chamber using hydrogen sulfide and phosphine sources, respectively. The activations were studied as functions of rf power, system pressure, and substrate material. Results show that higher rf powers and lower system pressures promote greater surface coverages by sulfur with a reduced oxidation state. The activated dielectrics show evidence of PdII(hfac)2 chemisorption, in contrast to non-activated surfaces. The binding energy shift of the Pd3d 5/2 XPS peak towards elemental Pd provides evidence for the dissociative chemisorption of PdII(hfac)2. The extent of dissociation depends on the substrate temperature and the activation method used. The conclusions of the work presented here have implications for metallization using highly polarizable transition metals. Specifically, it can be applied to

  1. Effects of Surface Treatment of Activated Carbon on Its Surface and Cr(VI) Adsorption Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Jin; Jang, Yu Sin [Advanced Materials Division., Korea Research Institute of Chimical Technology, Taejon (Korea)

    2001-04-01

    In this work, the effect of surface treatments on activated carbons (ACs) has been studied in the context of gas and liquid adsorption behaviors. The chemical solutions used in this experiment were 35% sodium hydroxide, and these were used for the acidic and basic treatments, respectively. The surface properties have been determined by pH, acid-base values, and FT-IR. The adsorption isotherms of Cr(VI) ion on activated carbons have been studied with the 5 mg/l concentration at ambient temperature. N{sub 2} adsorption isotherm characteristics, which include the specific surface area, micro pore volume, and microporosity, were determined by BET and Boer's-plot methods. In case of the acidic treatment of activated carbons, it was observed that the adsorption of Cr(VI) ion was more effective due to the increase acid value (or acidic functional group) of activated carbon surfaces. However, the basic treatment on activated carbons was caused no significant effects, probably due to the decreased specific surface area and total pore volume. 27 refs., 7 figs., 4 tabs.

  2. Response surface optimisation for activation of bentonite with microwave irradiation

    Directory of Open Access Journals (Sweden)

    Rožić Ljiljana S.

    2011-01-01

    Full Text Available In this study, the statistical design of the experimental method was applied on the acid activation process of bentonite with microwave irradiation. The influence of activation parameters (time, acid normality and microwave heating power on the selected process response of the activated bentonite samples was studied. The specific surface area was chosen for the process response, because the chemical, surface and structural properties of the activated clay determine and limit its potential applications. The relationship of various process parameters with the specific surface area of bentonite was examined. A mathematical model was developed using a second-order response surface model (RSM with a central composite design incorporating the above mentioned process parameters. The mathematical model developed helped in predicting the variation in specific surface area of activated bentonite with time (5-21 min, acid normality (2-7 N and microwave heating power (63-172 W. The calculated regression models were found to be statistically significant at the required range and presented little variability. Furthermore, high values of R2 (0.957 and R2 (adjusted (0.914 indicate a high dependence and correlation between the observed and the predicted values of the response. These high values also indicate that about 96% of the result of the total variation can be explained by this model. In addition, the model shows that increasing the time and acid normality improves the textural properties of bentonites, resulting in increased specific surface area. This model also can be useful for setting an optimum value of the activation parameters for achieving the maximum specific surface area. An optimum specific surface area of 142 m2g-1 was achieved with an acid normality of 5.2 N, activation time of 7.38 min and microwave power of 117 W. Acid activation of bentonite was found to occur faster with microwave irradiation than with conventional heating. Microwave

  3. Linear response theory of activated surface diffusion with interacting adsorbates

    Energy Technology Data Exchange (ETDEWEB)

    Marti' nez-Casado, R. [Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ (United Kingdom); Sanz, A.S.; Vega, J.L. [Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); Rojas-Lorenzo, G. [Instituto Superior de Tecnologi' as y Ciencias Aplicadas, Ave. Salvador Allende, esq. Luaces, 10400 La Habana (Cuba); Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cienti' ficas, Serrano 123, 28006 Madrid (Spain); Miret-Artes, S., E-mail: s.miret@imaff.cfmac.csic.es [Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cienti' ficas, Serrano 123, 28006 Madrid (Spain)

    2010-05-12

    Graphical abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed. - Abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed.

  4. Low Energy Surface Activation of Zirconia Based Restorations.

    Science.gov (United States)

    Aboushelib, Moustafa N

    2016-03-01

    To evaluate the influence of low energy surface activation technique on the biaxial flexure strength of zirconia frameworks. Zirconia discs were prepared by cutting CAD/CAM zirconia blocks. Sintered discs were airborne particle abraded using one of the following particles: 30 μm alumina particles, 50 μm alumina particles, or modified round edges 30 μm alumina particles at low pressure. Scanning electron microscopy, x-ray diffraction analysis, surface roughness, and biaxial flexure strength tests were performed (n = 20). Fractured specimens were fractographically analyzed (α = 0.05). Low energy surface activation resulted in 7% monoclinic crystallographic transformation, increasing surface roughness from 0.05 to 0.3 μm and in significant increase in biaxial flexure strength (1718 MPa) compared 30 μm (1064 MPa), 50 μm (1210 MPa), and as-sintered specimens (1150 MPa). Low energy surface activation of zirconia specimens improved the biaxial flexure strength of zirconia frameworks without creation of surface damage. Clinical implications: by controlling particle size and shape of alumina, the flexure strength of zirconia restorations could be increased usinglow pressure particle abrasion.

  5. Particle surface area and bacterial activity in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

    2017-01-01

    Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, cultur...... for determining bacterial activity might provide a means for future monitoring and assessment of microbial water quality in aquaculture farming systems......Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation...

  6. Active surface system for the new Sardinia Radiotelescope

    Science.gov (United States)

    Orfei, Alessandro; Morsiani, Marco; Zacchiroli, Giampaolo; Maccaferri, Giuseppe; Roda, Juri; Fiocchi, Franco

    2004-09-01

    In this paper we'll describe the active surface system that will be provided on the new Italian radiotelescope being in the phase of erection in the Sardinia Island. SRT (Sardinia Radiotelescope) will be a 64m shaped dish working up to 100GHz by exploiting the active surface facility designed by the authors. This facility will overcome the effects of gravity deformations on the antenna gain and will also be used to re-shape in a parabolic form the primary mirror, in order to avoid large phase error contribution on the antenna gain for the highest frequencies placed on the primary focus. Together with the description of the SRT system, a wide overview will be given regarding our previous installation of an active surface system, that can be seen like a prototype for SRT, mounted on the 32m dish of the Noto antenna.

  7. Teknik Squat dan Stoop Menggunakan Electromyography pada Pekerjaan Manual Materials Handling

    Directory of Open Access Journals (Sweden)

    I Wayan Surata

    2013-01-01

    Full Text Available Manual materials handling has been identified as the most common cause of work-related musculoskeletal disorders. Among the manual material handling activities, lifting has long been regarded as an activity associated with a high risk of low-back pain. Lifting studies have mainly focused on the squat and stoop lifting techniques as an effort to improve the protection of workers from low back discomfort. However, neither is ideal and the benefits of one technique over another have proved inconclusive. The purpose of this study was to examine and compare the squat and stoop lifting techniques through analysis of muscles activation by using electromyography. Six volunteers participated in the study, and were required to lift a weight with squat and stoop techniques, with two types of loading at 1,7 kg and 6,7 kg. Observations were made on the rectus femoris, biceps femoris, and multifidus muscles. The results of study showed that the squat technique had higher levels of muscle activation compared to stoop technique on rectus femoris muscle. On the contrary, squat technique had lower muscle activation compared to stoop technique on biceps fermoris muscle. Meanwhile, both techniques squat and stoop had the same level of muscle activation on multifidus muscle. Conclusion, squat and stoop lifting techniques had the same opportunities to use.

  8. Development of Hand Grip Assistive Device Control System for Old People through Electromyography (EMG Signal Acquisitions

    Directory of Open Access Journals (Sweden)

    Khamis Herman

    2017-01-01

    Full Text Available The hand grip assistive device is a glove to assist old people who suffer from hand weakness in their daily life activities. The device earlier control system only use simple on and off switch. This required old people to use both hand to activate the device. The new control system of the hand grip assistive device was developed to allow single hand operation for old people. New control system take advantages of electromyography (EMG and flex sensor which was implemented to the device. It was programmed into active and semi-active mode operation. EMG sensors were placed on the forearm to capture EMG signal of Flexor Digitorum Profundus muscle to activate the device. Flex sensor was used to indicate the finger position and placed on top of the finger. The signal from both sensors then used to control the device. The new control system allowed single hand operation and designed to prevent user from over depended on the device by activating it through moving their fingers.

  9. Concentric needle single fiber electromyography: normative jitter values on voluntary activated Extensor Digitorum Communis Eletromiografia de fibra única com agulha concêntrica: valores normativos do jitter no estudo por contração voluntária do músculo Extensor Digitorum Communis

    Directory of Open Access Journals (Sweden)

    João Aris Kouyoumdjian

    2007-06-01

    Full Text Available Single fiber electromyography (SFEMG is the most sensitive clinical neurophysiological test for neuromuscular junction disorders, particularly myasthenia gravis. Normal values for jitter obtained with SFEMG electrode have been published, but there are few publications for concentric needle electrode (CNE. The aim of this study was to discuss the possibilities to analyse the jitter in CNE recordings and to get normal values of jitter for voluntary activated Extensor Digitorum Communis using disposable CNE. Fifty normal subjects were studied, 16 male and 34 female with a mean age of 37.1±10.3 years (19-55. The jitter values of action potentials pairs of isolated muscular fibers were expressed as the mean consecutive difference (MCD after 20 analysed potential pairs. The mean MCD (n=50 obtained was 24.2±2.8 µs (range of mean values in each subject was 18-31. Upper 95% confidence limit is 29.8 µs. The mean jitter of all potential pairs (n=1000 obtained was 24.07±7.30 µs (range 9-57. A practical upper limit for individual data is set to 46 µs. The mean interpotential interval (MIPI was 779±177 µs (range of individual mean values was 530-1412; there were no potentials with impulse blocking. The present study confirms that CNE is suitable for jitter analysis although certain precautions must be mentioned. Our findings of jitter values with CNE were similar to some other few reports in literature.Eletromiografia de fibra única (SFEMG é o método eletrofisiológico mais sensível para diagnóstico das desordens de junção neuromuscular, particularmente miastenia gravis. Jitter obtido por meio de eletrodo de SFEMG já foi padronizado, porém há poucas publicações com uso de eletrodo de agulha concêntrica (CNE. O objetivo deste estudo é discutir as possibilidades de analisar o jitter por registro com CNE e obter valores normativos para o músculo Extensor Digitorum Communis por ativação muscular mínima. Foram estudados 50 indiv

  10. Effect of surface wettability caused by radiation induced surface activation on leidenfrost condition

    Energy Technology Data Exchange (ETDEWEB)

    Takamasa, T.; Hazuku, T.; Tamura, N.; Okamoto, K. [Tokyo Univ., Tokyo (Japan); Mishima, K. [Kyoto Univ., Kyoto (Japan); Furuya, M. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    2003-07-01

    Improving the limit of boiling heat transfer or critical heat flux requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. From this basis, we investigated surface wettability and Leidenfrost condition using metal oxides irradiated by {gamma}-rays. In our previous study, contact angle, an indicator of macroscopic wettability, of a water droplet on metal oxide at room temperature was measured by image processing of the images obtained by a CCD video camera. The results showed that the surface wettability on metal oxide pieces of titanium, Zircaloy No. 4, SUS-304, and copper was improved significantly by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of Radiation Induced Surface Activation (RISA) on heat transferring phenomena, the Leidenfrost condition and quenching of metal oxides irradiated by {gamma}-rays were investigated. In the Leidenfrost experiment, when the temperature of the heating surface reached the wetting limit temperature, water-solid contact vanished because a stable vapor film existed between the droplet and the metal surface; i.e., a Leidenfrost condition obtained. The wetting limit temperature increased with integrated irradiation dose. After irradiation, the wet length and the duration of contact increased, and the contact angle decreased. In the quenching test, high surface wettability, or a highly hydrophilic condition, of a simulated fuel rod made of SUS was achieved, and the quenching velocities were increased up to 20-30% after 300 kGy 60Co {gamma}-ray irradiation.

  11. Mechanism of Hydrophilicity by Radiation-Induced Surface Activation

    Science.gov (United States)

    Honjo, Yoshio; Furuya, Masahiro; Takamasa, Tomoji; Okamoto, Koji

    When a metal oxide is irradiated by gamma rays, the irradiated surface becomes hydrophilic. This surface phenomenon is called as radiation-induced surface activation (RISA) hydrophilicity. In order to investigate gamma ray-induced and photoinduced hydrophilicity, the contact angles of water droplets on a titanium dioxide surface were measured in terms of irradiation intensity and time for gamma rays of cobalt-60 and for ultraviolet rays. Reciprocals of the contact angles increased in proportion to the irradiation time before the contact angles reached its super-hydrophilic state. The irradiation time dependency is equal to each other qualitatively. In addition, an effect of ambient gas was investigated. In pure argon gas, the contact angle remains the same against the irradiation time. This clearly indicates that certain humidity is required in ambient gas to take place of RISA hydrophilicity. A single crystal titanium dioxide (100) surface was analyzed by X-ray photoelectron spectrometry (XPS). After irradiation with gamma rays, a peak was found in the O1s spectrum, which indicates the adsorption of dissociative water to a surface 5-fold coordinate titanium site, and the formation of a surface hydroxyl group. We conclude that the RISA hydrophilicity is caused by chemisorption of the hydroxyl group on the surface.

  12. Surface activation of dyed fabric for cellulase treatment.

    Science.gov (United States)

    Schimper, Christian B; Ibanescu, Constanta; Bechtold, Thomas

    2011-10-01

    Surface activation of fabric made from cellulose fibres, such as viscose, lyocell, modal fibres and cotton, can be achieved by printing of a concentrated NaOH-containing paste. From the concentration of reducing sugars formed in solution, an increase in intensity of the cellulase hydrolysis by a factor of six to eight was observed, which was mainly concentrated at the activated parts of the fabric surface. This method of local activation is of particular interest for modification of materials that have been dyed with special processes to attain an uneven distribution of dyestuff within the yarn cross-section, e.g., indigo ring-dyed denim yarn for jeans production. Fabrics made from regenerated cellulose fibres were used as model substrate to express the effects of surface activation on indigo-dyed material. Wash-down experiments on indigo-dyed denim demonstrated significant colour removal from the activated surface at low overall weight loss of 4-5%. The method is of relevance for a more eco-friendly processing of jeans in the garment industry. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Immune complement activation is attenuated by surface nanotopography

    Directory of Open Access Journals (Sweden)

    Elwing H

    2011-10-01

    Full Text Available Mats Hulander1, Anders Lundgren1, Mattias Berglin1, Mattias Ohrlander2, Jukka Lausmaa3,4, Hans Elwing1 1Department of Cell and Molecular Biology/Interface Biophysics, University of Gothenburg, Medicinaregatan 9E, Gothenburg, 2Bactiguard AB, Stockholm, 3SP Technical Research Institute, Boras, 4Biomatcell, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden Abstract: The immune complement (IC is a cell-free protein cascade system, and the first part of the innate immune system to recognize foreign objects that enter the body. Elevated activation of the system from, for example, biomaterials or medical devices can result in both local and systemic adverse effects and eventually loss of function or rejection of the biomaterial. Here, the researchers have studied the effect of surface nanotopography on the activation of the IC system. By a simple nonlithographic process, gold nanoparticles with an average size of 58 nm were immobilized on a smooth gold substrate, creating surfaces where a nanostructure is introduced without changing the surface chemistry. The activation of the IC on smooth and nanostructured surfaces was viewed with fluorescence microscopy and quantified with quartz crystal microbalance with dissipation monitoring in human serum. Additionally, the ability of pre-adsorbed human immunoglobulin G (IgG (a potent activator of the IC to activate the IC after a change in surface hydrophobicity was studied. It was found that the activation of the IC was significantly attenuated on nanostructured surfaces with nearly a 50% reduction, even after pre-adsorption with IgG. An increase in surface hydrophobicity blunted this effect. The possible role of the curvature of the nanoparticles for the orientation of adsorbed IgG molecules, and how this can affect the subsequent activation of the IC, are discussed. The present findings are important for further understanding of how surface nanotopography affects complex protein

  14. Active screen plasma nitriding enhances cell attachment to polymer surfaces

    International Nuclear Information System (INIS)

    Kaklamani, Georgia; Bowen, James; Mehrban, Nazia; Dong, Hanshan; Grover, Liam M.; Stamboulis, Artemis

    2013-01-01

    Active screen plasma nitriding (ASPN) is a well-established technique used for the surface modification of materials, the result of which is often a product with enhanced functional performance. Here we report the modification of the chemical and mechanical properties of ultra-high molecular weight poly(ethylene) (UHMWPE) using 80:20 (v/v) N 2 /H 2 ASPN, followed by growth of 3T3 fibroblasts on the treated and untreated polymer surfaces. ASPN-treated UHMWPE showed extensive fibroblast attachment within 3 h of seeding, whereas fibroblasts did not successfully attach to untreated UHMWPE. Fibroblast-coated surfaces were maintained for up to 28 days, monitoring their metabolic activity and morphology throughout. The chemical properties of the ASPN-treated UHMWPE surface were studied using X-ray photoelectron spectroscopy, revealing the presence of C-N, C=N, and C≡N chemical bonds. The elastic modulus, surface topography, and adhesion properties of the ASPN-treated UHMWPE surface were studied over 28 days during sample storage under ambient conditions and during immersion in two commonly used cell culture media.

  15. Abdominal strengthening using the AbVice machine as measured by surface electromyographic activation levels.

    Science.gov (United States)

    Avedisian, Lori; Kowalsky, Don S; Albro, Richard C; Goldner, Daniel; Gill, Robert C

    2005-08-01

    Twenty-four college students served as subjects in a study that examined the effect of a prototypical abdominal muscle strengthening device (AbVice) compared with other devices currently on the market. The purpose of the present study was to investigate a prototypical device (AbVice) that incorporates contraction of the hamstring and gluteal musculature in conjunction with the abdominals, which may assist in decreasing activation of the hip flexors by allowing greater activity levels of the abdominal musculature via the theory of reflex inhibition, compared with other devices currently available on the market (AbRoller and AbRocker). The repeated-measures study included 17 women and 7 men who ranged in age from 20-23 years (mean +/- SD age, 21.3 +/- 1.5 years). Each subject underwent a single session of data collection during which they completed 10 repetitions of abdominal crunches per device. Subjects completed 4 different crunch sets (AbRocker, AbRoller, standard crunch, AbVice). Counterbalancing of the device was used to negate the effect of fatigue. Speed of repetitions was ensured via use of a metronome set at 40 b.min(-1) to permit similar contraction times and rest periods between repetitions. Rest between conditions was 3 minutes. Mean activation levels of surface electromyography (EMG) were recorded for each condition at the following locations on the right side of the body: rectus abdominis 2.5 cm superior to the umbilicus, rectus abdominis 2.5 cm inferior to the umbilicus, external oblique abdominis 1.0 cm medial to the anterior superior iliac spine, and external oblique abdominis less than 1.0 cm superior to the inguinal ligament. Mean (SD) activation was 1,165.21 mV (634.60 mV) with the AbVice, 242.92 mV (263.03 mV) with the AbRocker, 753.29 mV (514.80 mV) with the standard crunch, and 757.67 mV (542.85 mV) with the AbRoller. Broken down by sex, women had the following mean (SD) EMG values: 1,079.76 mV (705.02 mV) with the AbVice, 680.35 mV (535.35 m

  16. Positioning of pedicle screws in adolescent idiopathic scoliosis using electromyography

    Directory of Open Access Journals (Sweden)

    Bruno Moreira Gavassi

    2015-06-01

    Full Text Available OBJECTIVE: To analyze the occurrence of poor positioning of pedicle screws inserted with the aid of intraoperative electromyographic stimulation in the treatment of Adolescent Idiopathic Scoliosis (AIS.METHODS: This is a prospective observational study including all patients undergoing surgical treatment for AIS, between March and December 2013 at a single institution. All procedures were monitored by electromyography of the inserted pedicle screws. The position of the screws was evaluated by assessment of postoperative CT and classified according to the specific AIS classification system.RESULTS: Sixteen patients were included in the study, totalizing 281 instrumented pedicles (17.5 per patient. No patient had any neurological deficit or complaint after surgery. In the axial plane, 195 screws were found in ideal position (69.4% while in the sagittal plane, 226 screws were found in ideal position (80.4%. Considering both the axial and the sagittal planes, it was observed that 59.1% (166/281 of the screws did not violate any cortical wall.CONCLUSION: The use of pedicle screws proved to be a safe technique without causing neurological damage in AIS surgeries, even with the occurrence of poor positioning of some implants.

  17. Value of Laryngeal Electromyography in Spasmodic Dysphonia Diagnosis and Therapy.

    Science.gov (United States)

    Yang, Qingwen; Xu, Wen; Li, Yun; Cheng, Liyu

    2015-07-01

    To investigate the role of laryngeal electromyography (LEMG) in the diagnosis and treatment of spasmodic dysphonia (SD). The clinical manifestations, characteristics of motor unit potentials (MUPs), recruitment potentials, and laryngeal nerve evoked potentials (EPs) in LEMG, as well as the changes after botulinum toxin (BTX) treatment, were analyzed in 39 patients with adductor SD. The main clinical manifestations were a strained voice and phonation interruptions; in addition, the patients displayed hyper-adducted vocal folds during phonation. LEMG revealed significantly increased amplitudes of the thyroarytenoid muscle MUPs. The recruitment potentials were in a dense bunch, discharging full interference patterns with significantly increased amplitudes; the mean and maximum amplitude of recruitment potentials were 3090 μV and 5000 μV, respectively. The amplitude of EPs of thyroarytenoid muscle increased significantly; the mean and maximum amplitudes were 10.3 mV and 26.3 mV, respectively. After BTX was injected, the LEMG revealed denervation changes, and the EPs weakened or disappeared in the injected muscle. SD could be diagnosed, and the therapeutic efficacy of SD treatments could be evaluated based on clinical characteristics combined with LEMG characteristics. The increased amplitudes of the recruitment potentials and EPs of the thyroarytenoid muscle were the characteristic indexes. After BTX was injected, denervated potential characteristics appeared in the muscles. © The Author(s) 2015.

  18. Quantitative electromyography in ambulatory boys with Duchenne muscular dystrophy.

    Science.gov (United States)

    Verma, Sumit; Lin, Jenny; Travers, Curtis; McCracken, Courtney; Shah, Durga

    2017-12-01

    This study's objective was to evaluate quantitative electromyography (QEMG) using multiple-motor-unit (multi-MUP) analysis in Duchenne muscular dystrophy (DMD). Ambulatory DMD boys, aged 5-15 years, were evaluated with QEMG at 6-month intervals over 14 months. EMG was performed in the right biceps brachii (BB) and tibialis anterior (TA) muscles. Normative QEMG data were obtained from age-matched healthy boys. Wilcoxon signed-rank tests were performed. Eighteen DMD subjects were enrolled, with a median age of 7 (interquartile range 7-10) years. Six-month evaluations were performed on 14 subjects. QEMG showed significantly abnormal mean MUP duration in BB and TA muscles, with no significant change over 6 months. QEMG is a sensitive electrophysiological marker of myopathy in DMD. Preliminary data do not reflect a significant change in MUP parameters over a 6-month interval; long-term follow-up QEMG studies are needed to understand its role as a biomarker for disease progression. Muscle Nerve 56: 1361-1364, 2017. © 2017 Wiley Periodicals, Inc.

  19. Spectroscopic Study of the Surface Oxidation of Mechanically Activated Sulphides

    Czech Academy of Sciences Publication Activity Database

    Godočíková, E.; Baláž, P.; Bastl, Zdeněk; Brabec, Libor

    2002-01-01

    Roč. 200, č. 1 (2002), s. 36-47 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z4040901 Keywords : mechanical activation * surface oxidation * sulphide minerals Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.295, year: 2002

  20. Temperature effects on surface activity and application in oxidation ...

    Indian Academy of Sciences (India)

    Unknown

    Surface activity; cetyl trimethylammonium bromide; sodium dodecyl sulfate; temperature; oxidation. 1. Introduction. Cationic systems show strong synergism in their so- lutions and display physicochemical properties that differ distinctly from those of individual surfactants,1 due to their electrostatic interaction between oppo-.

  1. Improved efficiency of budesonide nebulization using surface-active agents

    NARCIS (Netherlands)

    Heijstra, M. P.; Schaefer, N. C.; Duiverman, E. J.; LeSouef, P. N.; Devadason, S. G.

    2006-01-01

    Our aim was to improve the efficiency of nebulised budesonide using surface-active agents. Cationic, anionic, and nonionic detergents were added to commercial budesonide suspension, and the particle size distribution during nebulization was measured using both cascade impaction and laser

  2. Controlling hydrogenation activity and selectivity of bimetallic surfaces and catalysts

    Science.gov (United States)

    Murillo, Luis E.

    Studies of bimetallic systems are of great interest in catalysis due to the novel properties that they often show in comparison with the parent metals. The goals of this dissertation are: (1) to expand the studies of self-hydrogenation and hydrogenation reactions on bimetallic surfaces under ultra high vacuum conditions (UHV) using different hydrocarbon as probe molecules; (2) to attempt to correlate the surface science findings with supported catalyst studies under more realistic conditions; and (3) to investigate the competitive hydrogenation of C=C versus C=O bonds on Pt(111) modified by different 3d transition metals. Hydrogenation studies using temperature programmed desorption (TPD) on Ni/Pt(111) bimetallic surfaces have demonstrated an enhancement in the low temperature hydrogenation activity relative to that of clean Pt(111). This novel hydrogenation pathway can be achieved under UHV conditions by controlling the structures of the bimetallic surfaces. A low temperature hydrogenation activity of 1-hexene and 1-butene has been observed on a Pt-Ni-Pt(111) subsurface structure, where Ni atoms are mainly present on the second layer of the Pt(111) single crystal. These results are in agreement with previous studies of self-hydrogenation and hydrogenation of cyclohexene. However, a much higher dehydrogenation activity is observed in the reaction of cyclohexene to produce benzene, demonstrating that the hydrocarbon structure has an effect on the reaction pathways. On the other hand, self-hydrogenation of 1-butene is not observed on the Pt-Ni-Pt(111) surface, indicating that the chain length (or molecular weight) has a significant effect on the selfhydrogenation activity. The gas phase reaction of cyclohexene on Ni/Pt supported on alumina catalysts has also shown a higher self-hydrogenation activity in comparison with the same reaction performed on supported monometallic catalysts. The effects of metal loading and impregnation sequence of the metal precursors are

  3. Mirror neurons and intention understanding: Dissociating the contribution of object type and intention to mirror responses using electromyography.

    Science.gov (United States)

    Ruggiero, Maura; Catmur, Caroline

    2018-01-18

    Since their discovery in the monkey and human brain, mirror neurons have been claimed to play a key role in understanding others' intentions. For example, "action-constrained" mirror neurons in inferior parietal lobule fire when the monkey observes a grasping movement that is followed by an eating action, but not when it is followed by a placing action. It is claimed these responses enable the monkey to predict the intentions of the actor. These findings have been replicated in human observers by recording electromyography responses of the mouth-opening mylohyoid muscle during action observation. Mylohyoid muscle activity was greater during the observation of actions performed with the intention to eat than of actions performed with the intention to place, again suggesting an ability to predict the actor's intentions. However, in previous studies, intention was confounded with object type (food for eating actions, nonfood for placing actions). We therefore used electromyography to measure mylohyoid activity in participants observing eating and placing actions. Unlike previous studies, we used a design in which each object (food, nonfood) could be both eaten and placed, and thus participants could not predict the actor's intention at the onset of the action. Greater mylohyoid activity was found for the observation of actions performed on food objects, irrespective of intention, indicating that the object type, not the actor's intention, drives the mirror response. This result suggests that observers' motor responses during action observation reflect the presence of a particular object, rather than the actor's underlying intentions. © 2018 Society for Psychophysiological Research.

  4. Proximal Neuromuscular Control Protects Against Hamstring Injuries in Male Soccer Players: A Prospective Study With Electromyography Time-Series Analysis During Maximal Sprinting.

    Science.gov (United States)

    Schuermans, Joke; Danneels, Lieven; Van Tiggelen, Damien; Palmans, Tanneke; Witvrouw, Erik

    2017-05-01

    With their unremittingly high incidence rate and detrimental functional repercussions, hamstring injuries remain a substantial problem in male soccer. Proximal neuromuscular control ("core stability") is considered to be of key importance in primary and secondary hamstring injury prevention, although scientific evidence and insights on the exact nature of the core-hamstring association are nonexistent at present. The muscle activation pattern throughout the running cycle would not differ between participants based on injury occurrence during follow-up. Case-control study; Level of evidence, 3. Sixty amateur soccer players participated in a multimuscle surface electromyography (sEMG) assessment during maximal acceleration to full-speed sprinting. Subsequently, hamstring injury occurrence was registered during a 1.5-season follow-up period. Hamstring, gluteal, and trunk muscle activity time series during the airborne and stance phases of acceleration were evaluated and statistically explored for a possible causal association with injury occurrence and absence from sport during follow-up. Players who did not experience a hamstring injury during follow-up had significantly higher amounts of gluteal muscle activity during the front swing phase ( P = .027) and higher amounts of trunk muscle activity during the backswing phase of sprinting ( P = .042). In particular, the risk of sustaining a hamstring injury during follow-up lowered by 20% and 6%, with a 10% increment in normalized muscle activity of the gluteus maximus during the front swing and the trunk muscles during the backswing, respectively ( P hamstring injury occurrence in male soccer players. Higher amounts of gluteal and trunk muscle activity during the airborne phases of sprinting were associated with a lower risk of hamstring injuries during follow-up. Hence, the present results provide a basis for improved, evidence-based rehabilitation and prevention, particularly focusing on increasing neuromuscular

  5. Determination of effective treatment duration of interferential current therapy using electromyography

    OpenAIRE

    Youn, Jong-In; Lee, Ho Sub; Lee, Sangkwan

    2016-01-01

    [Purpose] This study used electromyography to measure the effective treatment duration of interferential current therapy for muscle fatigue. [Subjects and Methods] Fifteen healthy adult men volunteered to participate in the study (age: 24.2 ? 1.3?years; weight: 67.6 ? 4.92?kg; height: 176.4 ? 4.92?cm). All subjects performed 5?min of isometric back extension exercise to produce muscle fatigue, and were then treated with interferential current therapy for 15?min, with electromyography monitori...

  6. Surface active complexes formed between keratin polypeptides and ionic surfactants.

    Science.gov (United States)

    Pan, Fang; Lu, Zhiming; Tucker, Ian; Hosking, Sarah; Petkov, Jordan; Lu, Jian R

    2016-12-15

    Keratins are a group of important proteins in skin and hair and as biomaterials they can provide desirable properties such as strength, biocompatibility, and moisture regaining and retaining. The aim of this work is to develop water-soluble keratin polypeptides from sheep wool and then explore how their surface adsorption behaves with and without surfactants. Successful preparation of keratin samples was demonstrated by identification of the key components from gel electrophoresis and the reproducible production of gram scale samples with and without SDS (sodium dodecylsulphate) during wool fibre dissolution. SDS micelles could reduce the formation of disulphide bonds between keratins during extraction, reducing inter-molecular crosslinking and improving keratin polypeptide solubility. However, Zeta potential measurements of the two polypeptide batches demonstrated almost identical pH dependent surface charge distributions with isoelectric points around pH 3.5, showing complete removal of SDS during purification by dialysis. In spite of different solubility from the two batches of keratin samples prepared, very similar adsorption and aggregation behavior was revealed from surface tension measurements and dynamic light scattering. Mixing of keratin polypeptides with SDS and C 12 TAB (dodecyltrimethylammonium bromide) led to the formation of keratin-surfactant complexes that were substantially more effective at reducing surface tension than the polypeptides alone, showing great promise in the delivery of keratin polypeptides via the surface active complexes. Neutron reflection measurements revealed the coexistence of surfactant and keratin polypeptides at the interface, thus providing the structural support to the observed surface tension changes associated with the formation of the surface active complexes. Copyright © 2016. Published by Elsevier Inc.

  7. Real-time and wearable functional electrical stimulation system for volitional hand motor function control using the electromyography bridge method

    Directory of Open Access Journals (Sweden)

    Hai-peng Wang

    2017-01-01

    Full Text Available Voluntary participation of hemiplegic patients is crucial for functional electrical stimulation therapy. A wearable functional electrical stimulation system has been proposed for real-time volitional hand motor function control using the electromyography bridge method. Through a series of novel design concepts, including the integration of a detecting circuit and an analog-to-digital converter, a miniaturized functional electrical stimulation circuit technique, a low-power super-regeneration chip for wireless receiving, and two wearable armbands, a prototype system has been established with reduced size, power, and overall cost. Based on wrist joint torque reproduction and classification experiments performed on six healthy subjects, the optimized surface electromyography thresholds and trained logistic regression classifier parameters were statistically chosen to establish wrist and hand motion control with high accuracy. Test results showed that wrist flexion/extension, hand grasp, and finger extension could be reproduced with high accuracy and low latency. This system can build a bridge of information transmission between healthy limbs and paralyzed limbs, effectively improve voluntary participation of hemiplegic patients, and elevate efficiency of rehabilitation training.

  8. Microstructure and surface properties of lignocellulosic-based activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Garcia, P., E-mail: pegonzal@quim.ucm.es [Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutense, E-28040, Madrid (Spain); Centeno, T.A. [Instituto Nacional del Carbon-CSIC, Apartado 73, E-33080 Oviedo (Spain); Urones-Garrote, E. [Centro Nacional de Microscopia Electronica, Universidad Complutense, E-28040, Madrid (Spain); Avila-Brande, D.; Otero-Diaz, L.C. [Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutense, E-28040, Madrid (Spain)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Activated carbons were produced by KOH activation at 700 Degree-Sign C. Black-Right-Pointing-Pointer The observed nanostructure consists of highly disordered graphene-like layers with sp{sup 2} bond content Almost-Equal-To 95%. Black-Right-Pointing-Pointer Textural parameters show high surface area ( Almost-Equal-To 1000 m{sup 2}/g) and pore width of 1.3-1.8 nm. Black-Right-Pointing-Pointer Specific capacitance reaches values as high as 161 F/g. - Abstract: Low cost activated carbons have been produced via chemical activation, by using KOH at 700 Degree-Sign C, from the bamboo species Guadua Angustifolia and Bambusa Vulgaris Striata and the residues from shells of the fruits of Castanea Sativa and Juglans Regia as carbon precursors. The scanning electron microscopy micrographs show the conservation of the precursor shape in the case of the Guadua Angustifolia and Bambusa Vulgaris Striata activated carbons. Transmission electron microscopy analyses reveal that these materials consist of carbon platelet-like particles with variable length and thickness, formed by highly disordered graphene-like layers with sp{sup 2} content Almost-Equal-To 95% and average mass density of 1.65 g/cm{sup 3} (25% below standard graphite). Textural parameters indicate a high porosity development with surface areas ranging from 850 to 1100 m{sup 2}/g and average pore width centered in the supermicropores range (1.3-1.8 nm). The electrochemical performance of the activated carbons shows specific capacitance values at low current density (1 mA/cm{sup 2}) as high as 161 F/g in the Juglans Regia activated carbon, as a result of its textural parameters and the presence of pseudocapacitance derived from surface oxygenated acidic groups (mainly quinones and ethers) identified in this activated carbon.

  9. Surface barrier silicon detectors with a large active area

    International Nuclear Information System (INIS)

    Kim, Y.; Husimi, K.; Ikeda, Y.; Kim, C.; Ohkawa, S.; Sakai, T.

    1985-01-01

    Surface barrier silicon detectors with a large active area have been produced by using high resistive n-type silicon crystals, diameters of which are 3 to 5 inches. High quality detectors with a low leakage current and a low noise were achieved by developing the improved surface treatment. Characteristics of detectors obtained are good in energy resolution compared with conventional large area Si(Li) detectors. It has also been confirmed that local dead region is not found from measuring results of photo-pulse injection

  10. Nanostructured surface topographies have an effect on bactericidal activity.

    Science.gov (United States)

    Wu, Songmei; Zuber, Flavia; Maniura-Weber, Katharina; Brugger, Juergen; Ren, Qun

    2018-02-28

    Due to the increased emergence of antimicrobial resistance, alternatives to minimize the usage of antibiotics become attractive solutions. Biophysical manipulation of material surface topography to prevent bacterial adhesion is one promising approach. To this end, it is essential to understand the relationship between surface topographical features and bactericidal properties in order to develop antibacterial surfaces. In this work a systematic study of topographical effects on bactericidal activity of nanostructured surfaces is presented. Nanostructured Ormostamp polymer surfaces are fabricated by nano-replication technology using nanoporous templates resulting in 80-nm diameter nanopillars. Six Ormostamp surfaces with nanopillar arrays of various nanopillar densities and heights are obtained by modifying the nanoporous template. The surface roughness ranges from 3.1 to 39.1 nm for the different pillar area parameters. A Gram-positive bacterium, Staphylococcus aureus, is used as the model bacterial strain. An average pillar density at ~ 40 pillars μm -2 with surface roughness of 39.1 nm possesses the highest bactericidal efficiency being close to 100% compared with 20% of the flat control samples. High density structures at ~ 70 pillars μm -2 and low density structures at bactericidal efficiency to almost the level of the control samples. The results obtained here suggests that the topographical effects including pillar density and pillar height inhomogeneity may have significant impacts on adhering pattern and stretching degree of bacterial cell membrane. A biophysical model is prepared to interpret the morphological changes of bacteria on these nanostructures.

  11. Energy expenditure and muscular activation patterns through active sitting on compliant surfaces

    Directory of Open Access Journals (Sweden)

    D. Clark Dickin

    2017-06-01

    Conclusion: Compliant surfaces resulted in higher levels of muscular activation in the lower extremities facilitating increased caloric expenditure. Given the increasing trends in sedentary careers and the increases in obesity, this is an important finding to validate the merits of active sitting facilitating increased caloric expenditure and muscle activation.

  12. Identification of first-stage labor arrest by electromyography in term nulliparous women after induction of labor.

    Science.gov (United States)

    Vasak, Blanka; Graatsma, Elisabeth M; Hekman-Drost, Elske; Eijkemans, Marinus J; Schagen van Leeuwen, Jules H; Visser, Gerard H A; Jacod, Benoit C

    2017-07-01

    Worldwide induction and cesarean delivery rates have increased rapidly, with consequences for subsequent pregnancies. The majority of intrapartum cesarean deliveries are performed for failure to progress, typically in nulliparous women at term. Current uterine registration techniques fail to identify inefficient contractions leading to first-stage labor arrest. An alternative technique, uterine electromyography has been shown to identify inefficient contractions leading to first-stage arrest of labor in nulliparous women with spontaneous onset of labor at term. The objective of this study was to determine whether this finding can be reproduced in induction of labor. Uterine activity was measured in 141 nulliparous women with singleton term pregnancies and a fetus in cephalic position during induced labor. Electrical activity of the myometrium during contractions was characterized by its power density spectrum. No significant differences were found in contraction characteristics between women with induced labor delivering vaginally with or without oxytocin and women with arrested labor with subsequent cesarean delivery. Uterine electromyography shows no correlation with progression of labor in induced labor, which is in contrast to spontaneous labor. © 2017 Nordic Federation of Societies of Obstetrics and Gynecology.

  13. Direct instrumental identification of catalytically active surface sites

    Science.gov (United States)

    Pfisterer, Jonas H. K.; Liang, Yunchang; Schneider, Oliver; Bandarenka, Aliaksandr S.

    2017-09-01

    The activity of heterogeneous catalysts—which are involved in some 80 per cent of processes in the chemical and energy industries—is determined by the electronic structure of specific surface sites that offer optimal binding of reaction intermediates. Directly identifying and monitoring these sites during a reaction should therefore provide insight that might aid the targeted development of heterogeneous catalysts and electrocatalysts (those that participate in electrochemical reactions) for practical applications. The invention of the scanning tunnelling microscope (STM) and the electrochemical STM promised to deliver such imaging capabilities, and both have indeed contributed greatly to our atomistic understanding of heterogeneous catalysis. But although the STM has been used to probe and initiate surface reactions, and has even enabled local measurements of reactivity in some systems, it is not generally thought to be suited to the direct identification of catalytically active surface sites under reaction conditions. Here we demonstrate, however, that common STMs can readily map the catalytic activity of surfaces with high spatial resolution: we show that by monitoring relative changes in the tunnelling current noise, active sites can be distinguished in an almost quantitative fashion according to their ability to catalyse the hydrogen-evolution reaction or the oxygen-reduction reaction. These data allow us to evaluate directly the importance and relative contribution to overall catalyst activity of different defects and sites at the boundaries between two materials. With its ability to deliver such information and its ready applicability to different systems, we anticipate that our method will aid the rational design of heterogeneous catalysts.

  14. Design parameters for measurements of local catalytic activity on surfaces

    DEFF Research Database (Denmark)

    Johansson, Martin; Johannessen, Tue; Jørgensen, Jan Hoffmann

    2006-01-01

    Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward...... the catalytic surface through the annulus between the tubes, and the gas is sampled close to the surface by the capillary. The influence of various design parameters on the lateral resolution and sensitivity of the measurements is investigated. It is found that the cuter diameter of the annulus sets the upper......, the limits of the range in reaction rate, which can be Studied are estimated. (c) 2005 Elsevier B.V. All rights reserved....

  15. Electromyography data for non-invasive naturally-controlled robotic hand prostheses.

    Science.gov (United States)

    Atzori, Manfredo; Gijsberts, Arjan; Castellini, Claudio; Caputo, Barbara; Hager, Anne-Gabrielle Mittaz; Elsig, Simone; Giatsidis, Giorgio; Bassetto, Franco; Müller, Henning

    2014-01-01

    Recent advances in rehabilitation robotics suggest that it may be possible for hand-amputated subjects to recover at least a significant part of the lost hand functionality. The control of robotic prosthetic hands using non-invasive techniques is still a challenge in real life: myoelectric prostheses give limited control capabilities, the control is often unnatural and must be learned through long training times. Meanwhile, scientific literature results are promising but they are still far from fulfilling real-life needs. This work aims to close this gap by allowing worldwide research groups to develop and test movement recognition and force control algorithms on a benchmark scientific database. The database is targeted at studying the relationship between surface electromyography, hand kinematics and hand forces, with the final goal of developing non-invasive, naturally controlled, robotic hand prostheses. The validation section verifies that the data are similar to data acquired in real-life conditions, and that recognition of different hand tasks by applying state-of-the-art signal features and machine-learning algorithms is possible.

  16. Electromyography data for non-invasive naturally-controlled robotic hand prostheses

    Science.gov (United States)

    Atzori, Manfredo; Gijsberts, Arjan; Castellini, Claudio; Caputo, Barbara; Hager, Anne-Gabrielle Mittaz; Elsig, Simone; Giatsidis, Giorgio; Bassetto, Franco; Müller, Henning

    2014-01-01

    Recent advances in rehabilitation robotics suggest that it may be possible for hand-amputated subjects to recover at least a significant part of the lost hand functionality. The control of robotic prosthetic hands using non-invasive techniques is still a challenge in real life: myoelectric prostheses give limited control capabilities, the control is often unnatural and must be learned through long training times. Meanwhile, scientific literature results are promising but they are still far from fulfilling real-life needs. This work aims to close this gap by allowing worldwide research groups to develop and test movement recognition and force control algorithms on a benchmark scientific database. The database is targeted at studying the relationship between surface electromyography, hand kinematics and hand forces, with the final goal of developing non-invasive, naturally controlled, robotic hand prostheses. The validation section verifies that the data are similar to data acquired in real-life conditions, and that recognition of different hand tasks by applying state-of-the-art signal features and machine-learning algorithms is possible. PMID:25977804

  17. Fuzzy approximate entropy analysis of chaotic and natural complex systems: detecting muscle fatigue using electromyography signals.

    Science.gov (United States)

    Xie, Hong-Bo; Guo, Jing-Yi; Zheng, Yong-Ping

    2010-04-01

    In the present contribution, a complexity measure is proposed to assess surface electromyography (EMG) in the study of muscle fatigue during sustained, isometric muscle contractions. Approximate entropy (ApEn) is believed to provide quantitative information about the complexity of experimental data that is often corrupted with noise, short data length, and in many cases, has inherent dynamics that exhibit both deterministic and stochastic behaviors. We developed an improved ApEn measure, i.e., fuzzy approximate entropy (fApEn), which utilizes the fuzzy membership function to define the vectors' similarity. Tests were conducted on independent, identically distributed (i.i.d.) Gaussian and uniform noises, a chirp signal, MIX processes, Rossler equation, and Henon map. Compared with the standard ApEn, the fApEn showed better monotonicity, relative consistency, and more robustness to noise when characterizing signals with different complexities. Performance analysis on experimental EMG signals demonstrated that the fApEn significantly decreased during the development of muscle fatigue, which is a similar trend to that of the mean frequency (MNF) of the EMG signal, while the standard ApEn failed to detect this change. Moreover, fApEn of EMG demonstrated a better robustness to the length of the analysis window in comparison with the MNF of EMG. The results suggest that the fApEn of an EMG signal may potentially become a new reliable method for muscle fatigue assessment and be applicable to other short noisy physiological signal analysis.

  18. Activity of the equine rectus abdominis and oblique external abdominal muscles measured by surface EMG during walk and trot on the treadmill.

    Science.gov (United States)

    Zsoldos, R R; Kotschwar, A; Kotschwar, A B; Rodriguez, C P; Peham, C; Licka, T

    2010-11-01

    The rectus abdominis (RA) and oblique external abdominal (OEA) muscles are both part of the construction of the equine trunk and thought to be essential for the function of the spine during locomotion. Although RA activity at trot has previously been investigated, the relationship between OEA and RA at walk and trot has not yet been described. To document abdominal muscle activities during walk and trot, and test the hypothesis that muscle activity at walk would be smaller than at trot. Six horses (8-20 years old, 450-700 kg) were used for surface electromyography (EMG) measurements, with EMG electrodes placed caudal to the sternum (RA) and at the level of the 16th rib (OEA). On all hooves, the withers and the sacrum reflective markers were placed to determine motion cycles. Normal distribution of data was tested using a Kolmogorov-Smirnov test and Student's t test was used to compare left-right and walk-trot differences (P activity ranged from 8-44 mV (RA) and 7-54 mV (OEA). At trot, EMG activity ranged from 18-150 mV (RA) and 27-239 mV (OEA). There were statistically significant differences between maximum activities of left and right OEA and RA muscles at walk in all horses, and in 4/6 horses at trot. Muscle activities of OEA and RA are smaller at walk than at trot. At walk, the OEA/RA ratio is lower than at trot. There are more significant correlations between muscle activities of both RA and OEA and limb movements at walk than at the trot. © 2010 EVJ Ltd.

  19. [Mechanism of post-stroke reflex sympathetic dystrophy: study with needle electromyography].

    Science.gov (United States)

    Wang, Xiao-yan; Zhang, Tong; Li, Jing

    2006-10-10

    To explore the mechanism of post-stroke reflex sympathetic dystrophy (RSD) patients electromyographic abnormality and confirm its clinical value. Fifty patients with first-onset stroke, aged 33 - 78, including 30 with RSD and 20 without RSD, underwent needle electromyography (EMG) to test the nerve conduction velocity (NCV) and sensory nerve conduction velocity (SCV) of bilateral median nerves, and the number and position of spontaneous EMG activity of bilateral short abductor muscles of thumb and abductor muscles little finger. The median nerve compound muscle action potential (CMAP) amplitude of the affected upper extremities of the RSD group was 8.6 mV +/- 2.9 mV, significantly lower than that of the non-RSD group (13.2 mV +/- 4.6 mV, P < 0.01). The incidence of spontaneous electrical potential of the RSD group was 100%; significantly higher than hat of the non-RSD group (65%, P < 0.001). The quantity of spontaneous EMG activity on the short abductor muscles of thumb and abductor muscles little finger was increased in the RSD group (P < 0.01). The motor nerve conduction velocity and electrophysiological presentation of sensory nerve of these 2 groups were all normal and without significant differences between them. Partial axonal degeneration occurs on the distal motor never fibers of the affected upper extremity of the RSD patients, which may be related to subsequent peripheral nerve injury after central nerve system impairment.

  20. Immediate effects of respiratory muscle stretching on chest wall kinematics and electromyography in COPD patients.

    Science.gov (United States)

    de Sá, Rafaela Barros; Pessoa, Maíra Florentino; Cavalcanti, Ana Gabriela Leal; Campos, Shirley Lima; Amorim, César; Dornelas de Andrade, Armèle

    2017-08-01

    This study evaluated the immediate effects of respiratory muscle stretching on chest wall kinematics and electromyographic activity in COPD patients. 28 patients with COPD were randomized into two groups: 14 to the treatment group (TG) and 14 to the control group (CG). The TG underwent a stretching protocol of the rib cage muscles, while the CG remained at rest under similar conditions. After a single session, TG increased the tidal volume of the pulmonary rib cage (Vrcp) (p=0.020) and tidal volume of abdominal rib cage (Vrca) (p=0.043) variations and their percentages in relation to the thoracic wall, Vrcp% (p=0.044) and Vrca% (p=0.022). Also, TG decreased the end-expiratory Vrcp (p=0.013) and the end-inspiratory Vrcp (p=0.011) variations. In addition, there was a reduction in respiratory rate (RR) (p=0.011) and minute volume (MV) (p=0.035), as well as an increase in expiratory time (Te) (p=0.026). There was also an immediate reduction in sternocleidomastoid (p=0.043) and upper trapezium (p=0.034) muscle electrical activity. Then, the study supports the use of stretching to improve COPD chest wall mobility with positive effects on chest wall mechanics, on volume distribution and electromyography. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Evoked electromyography-based closed-loop torque control in functional electrical stimulation.

    Science.gov (United States)

    Zhang, Qin; Hayashibe, Mitsuhiro; Azevedo-Coste, Christine

    2013-08-01

    This paper proposed a closed-loop torque control strategy of functional electrical stimulation (FES) with the aim of obtaining an accurate, safe, and robust FES system. Generally, FES control systems are faced with the challenge of how to deal with time-variant muscle dynamics due to physiological and biochemical factors (such as fatigue). The degraded muscle force needs to be compensated in order to ensure the accuracy of the motion restored by FES. Another challenge concerns the fact that implantable sensors are unavailable to feedback torque information for FES in humans. As FES-evoked electromyography (EMG) represents the activity of stimulated muscles, and also enables joint torque prediction as presented in our previous studies, here we propose an EMG-feedback predictive controller of FES to control joint torque adaptively. EMG feedback contributes to taking the activated muscle state in the FES torque control system into account. The nature of the predictive controller facilitates prediction of the muscle mechanical response and the system can therefore control joint torque from EMG feedback and also respond to time-variant muscle state changes. The control performance, fatigue compensation and aggressive control suppression capabilities of the proposed controller were evaluated and discussed through experimental and simulation studies.

  2. Source localization in electromyography using the inverse potential problem

    Science.gov (United States)

    van den Doel, Kees; Ascher, Uri M.; Pai, Dinesh K.

    2011-02-01

    We describe an efficient method for reconstructing the activity in human muscles from an array of voltage sensors on the skin surface. MRI is used to obtain morphometric data which are segmented into muscle tissue, fat, bone and skin, from which a finite element model for volume conduction is constructed. The inverse problem of finding the current sources in the muscles is solved using a careful regularization technique which adds a priori information, yielding physically reasonable solutions from among those that satisfy the basic potential problem. Several regularization functionals are considered and numerical experiments on a 2D test model are performed to determine which performs best. The resulting scheme leads to numerical difficulties when applied to large-scale 3D problems. We clarify the nature of these difficulties and provide a method to overcome them, which is shown to perform well in the large-scale problem setting.

  3. Source localization in electromyography using the inverse potential problem

    International Nuclear Information System (INIS)

    Van den Doel, Kees; Ascher, Uri M; Pai, Dinesh K

    2011-01-01

    We describe an efficient method for reconstructing the activity in human muscles from an array of voltage sensors on the skin surface. MRI is used to obtain morphometric data which are segmented into muscle tissue, fat, bone and skin, from which a finite element model for volume conduction is constructed. The inverse problem of finding the current sources in the muscles is solved using a careful regularization technique which adds a priori information, yielding physically reasonable solutions from among those that satisfy the basic potential problem. Several regularization functionals are considered and numerical experiments on a 2D test model are performed to determine which performs best. The resulting scheme leads to numerical difficulties when applied to large-scale 3D problems. We clarify the nature of these difficulties and provide a method to overcome them, which is shown to perform well in the large-scale problem setting

  4. Hip Muscle Activity during Isometric Contraction of Hip Abduction

    OpenAIRE

    Fujisawa, Hiroyuki; Suzuki, Hiroto; Yamaguchi, Emi; Yoshiki, Hiromi; Wada, Yui; Watanabe, Aya

    2014-01-01

    [Purpose] This study aimed to determine the effect of varying hip flexion angle on hip muscle activity during isometric contraction in abduction. [Subjects] Twenty-seven healthy men (mean age=21.5 years, SD=1.2) participated in this study. [Methods] Surface electromyography (EMG) was recorded of the upper portion of the gluteus maximus (UGM), lower portion of the gluteus maximus (LGM), tensor fasciae latae (TFL), and gluteus medius (GMed) during isometric contraction under two measurement con...

  5. Fabrication of Bioactive Surfaces by Functionalization of Electroactive and Surface-Active Block Copolymers

    Directory of Open Access Journals (Sweden)

    Omotunde Olubi

    2014-08-01

    Full Text Available Biofunctional block copolymers are becoming increasingly attractive materials as active components in biosensors and other nanoscale electronic devices. We have described two different classes of block copolymers with biofuctional properties. Biofunctionality for block copolymers is achieved through functionalization with appropriate biospecific ligands. We have synthesized block copolymers of electroactive poly(3-decylthiophene and 2-hydroxyethyl methacrylate by atom transfer radical polymerization. The block copolymers were functionalized with the dinitrophenyl (DNP groups, which are capable of binding to Immunoglobulin E (IgE on cell surfaces. The block copolymers were shown to be redox active. Additionally, the triblock copolymer of α, ω-bi-biotin (poly(ethylene oxide-b-poly (styrene-b-poly(ethylene oxide was also synthesized to study their capacity to bind fluorescently tagged avidin. The surface-active property of the poly(ethylene oxide block improved the availability of the biotin functional groups on the polymer surfaces. Fluorescence microscopy observations confirm the specific binding of biotin with avidin.

  6. Electromyographic activity of preterm newborns in the kangaroo position: a cohort study

    OpenAIRE

    Miranda, Rafael Moura; Cabral Filho, José Eulálio; Diniz, Kaísa Trovão; Souza Lima, Geisy Maria; Vasconcelos, Danilo de Almeida

    2014-01-01

    Objective To compare the electromyographic activity of preterm newborns placed in the kangaroo position with the activity of newborns not placed in this position. Design A cohort study. Setting A Kangaroo Unit sector and a Nursery sector in a secondary and tertiary care at a mother-child hospital in Recife, Brazil. Participants Preterm infants of gestational age 27–34 weeks (n=38) and term infants (n=39). Primary and secondary outcome measures Surface electromyography was used to investigate ...

  7. Influence of Hip Joint Position on Muscle Activity during Prone Hip Extension with Knee Flexion

    OpenAIRE

    Suehiro, Tadanobu; Mizutani, Masatoshi; Okamoto, Mitsuhisa; Ishida, Hiroshi; Kobara, Kenichi; Fujita, Daisuke; Osaka, Hiroshi; Takahashi, Hisashi; Watanabe, Susumu

    2014-01-01

    [Purpose] This study investigated the selective activation of the gluteus maximus during a prone hip extension with knee flexion exercise, with the hip joint in different positions. [Subjects] The subjects were 21 healthy, male volunteers. [Methods] Activities of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and bilateral lumbar multifidus were measured using surface electromyography during a prone hip extension with knee flexion exercise. Measurements were mad...

  8. A description of the BNL active surface analysis facility

    International Nuclear Information System (INIS)

    Tyler, J.W.

    1989-11-01

    Berkeley Nuclear Laboratories has a responsibility for the assessment of radioactive specimens arising both from post irradiation examination of power reactor components and structures and experimental programmes concerned with fission and activation product transport. Existing analytical facilities have been extended with the commissioning of an active surface analysis instrument (XSAM 800pci, Kratos Analytical). Surface analysis involves the characterisation of the outer few atomic layers of a solid surface/interface whose chemical composition and electronic structure will probably be different from the bulk. The new instrument consists three interconnected chambers positioned in series; comprising of a high vacuum sample introduction chamber, an ultra-high vacuum sample treatment/fracture chamber and an ultra-high vacuum sample analysis chamber. The sample analysis chamber contains the electron, X-ray and ion-guns and the electron and ion detectors necessary for performing X-ray photoelectron spectroscopy, scanning Auger microscopy and secondary-ion mass spectroscopy. The chamber also contains a high stability manipulator to enable sub-micron imaging of specimens to be achieved and provide sample heating and cooling between - 180 and 600 0 C. (author)

  9. Nitrate reducing activity pervades surface waters during upwelling

    Science.gov (United States)

    Fernandes, Sheryl Oliveira; Halarnekar, Reena; Malik, Ashish; Vijayan, Vijitha; Varik, Sandesh; Kumari, Ritu; V. K., Jineesh; Gauns, Manguesh U.; Nair, Shanta; LokaBharathi, P. A.

    2014-09-01

    Nitrate reducing activity (NRA) is known to be mediated by microaerophilic to anaerobic bacteria and generally occurs in the sub-surface waters. However, we hypothesize that NRA could become prominent in the surface waters during upwelling. Hence, we examined nitrification and nitrate reduction along with hydrographic and environmental parameters off Trivandrum and Kochi, south-west-India in June 2010. Shoaling isolines of temperature, density, and nutrients revealed the onset of upwelling off Trivandrum. Shoaling of these signatures was absent in the northern transect off Kochi. The degree of nutrient consumption (DNC) was low emphasizing the presence of newly upwelled water off Trivandrum. A significant increase in NRA (df = 1, p < 0.05) was observed off Trivandrum than at Kochi. Moreover, as hypothesized, NRA at Trivandrum was pronounced at the surface with a maximum rate of 0.85 (± 0.02) μmol L1 h- 1 nearshore which was ~ 29 × higher than that at Kochi. Further, an inverse relationship between NRA and NO3- concentration (n = 34, r = - 0.415, p < 0.01) suggested transformation of the upwelled nutrient. Nitrification/NRA was ~ 10 × lower at 0.28 off Trivandrum indicating a discernible shift towards reduction. Such contribution from bacterial activity could be a response towards restoration of homeostasis.

  10. Effects of electrocardiography contamination and comparison of ECG removal methods on upper trapezius electromyography recordings.

    Science.gov (United States)

    Marker, Ryan J; Maluf, Katrina S

    2014-12-01

    Electromyography (EMG) recordings from the trapezius are often contaminated by the electrocardiography (ECG) signal, making it difficult to distinguish low-level muscle activity from muscular rest. This study investigates the influence of ECG contamination on EMG amplitude and frequency estimations in the upper trapezius during muscular rest and low-level contractions. A new method of ECG contamination removal, filtered template subtraction (FTS), is described and compared to 30 Hz high-pass filter (HPF) and averaged template subtraction (ATS) methods. FTS creates a unique template of each ECG artifact using a low-pass filtered copy of the contaminated signal, which is subtracted from contaminated periods in the original signal. ECG contamination results in an over-estimation of EMG amplitude during rest in the upper trapezius, with negligible effects on amplitude and frequency estimations during low-intensity isometric contractions. FTS and HPF successfully removed ECG contamination from periods of muscular rest, yet introduced errors during muscle contraction. Conversely, ATS failed to fully remove ECG contamination during muscular rest, yet did not introduce errors during muscle contraction. The relative advantages and disadvantages of different ECG contamination removal methods should be considered in the context of the specific motor tasks that require analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. The Comparing the Leg Muscles Electromyography during Single Leg Drop Landing in Pesplanus and Normal Men

    Directory of Open Access Journals (Sweden)

    mostafa bazvand

    2016-03-01

    Full Text Available Objective: pesplanus is one of the changes that brings about changes in muscle activation patterns. Being aware of muscles activity changes in various standing positions among pesplanus patients provides insights into preventing lower extremity injuries in this population. The aim of this study was to compare leg muscles electromyography during various standing positions in pesplanus and normal subjects. Methods: 60 healthy male university students, 30 subjects with pesplanus deformity (with average age 23/54±3/57 year, average height 175/34±7/62 cm, average weight 74/87±10/72 kg and 30 normal subjects (with average age 22/97±2/38 year, average height 176/6±5/59 cm, average weight 73/58±8/36 kg participated in this comparative study. Deformity of pesplanus was assessed with navicular drop test. Each subject performed single-leg landing dropping from 30cm height onto a force platform where muscles activity was recorded with EMG device. For data analysis, Matlab and Spss softwares were used and independent sample t-test was used to compare the dependent variables at a significance level of P &le 0/05. Results: Significant differences were observed between the two groups for the activities of the longus peroneus and anterior tibialis muscles ( p&le0/05 while no significant differences were observed in other muscles. Conclusion: The changes in the normal structure of the foot might affect muscle activities during standing, which can cause changes in the injury patterns. Therefore, it is proposed that focusing on corrective exercises and therapy plan can reduce these risks.

  12. Determination of effective treatment duration of interferential current therapy using electromyography

    Science.gov (United States)

    Youn, Jong-In; Lee, Ho Sub; Lee, Sangkwan

    2016-01-01

    [Purpose] This study used electromyography to measure the effective treatment duration of interferential current therapy for muscle fatigue. [Subjects and Methods] Fifteen healthy adult men volunteered to participate in the study (age: 24.2 ± 1.3 years; weight: 67.6 ± 4.92 kg; height: 176.4 ± 4.92 cm). All subjects performed 5 min of isometric back extension exercise to produce muscle fatigue, and were then treated with interferential current therapy for 15 min, with electromyography monitoring (treatment group). After sufficient rest, the exercise was repeated for 5 min and an electromyography signal was acquired for 15 min with no treatment (control group). [Results] In the treatment group, the median frequency shifted to a higher level; the root mean square decreased over time, and then maintained a minimum amplitude. However, there were few changes in the electromyography signal after exercise in the control group. [Conclusion] Electromyography signals can provide information about the effective duration for muscle fatigue treatment as well as the muscle characteristics during treatment. This study should be helpful for clinicians by demonstrating the appropriate duration of therapy for relief of muscle stiffness. PMID:27630443

  13. Determination of effective treatment duration of interferential current therapy using electromyography.

    Science.gov (United States)

    Youn, Jong-In; Lee, Ho Sub; Lee, Sangkwan

    2016-08-01

    [Purpose] This study used electromyography to measure the effective treatment duration of interferential current therapy for muscle fatigue. [Subjects and Methods] Fifteen healthy adult men volunteered to participate in the study (age: 24.2 ± 1.3 years; weight: 67.6 ± 4.92 kg; height: 176.4 ± 4.92 cm). All subjects performed 5 min of isometric back extension exercise to produce muscle fatigue, and were then treated with interferential current therapy for 15 min, with electromyography monitoring (treatment group). After sufficient rest, the exercise was repeated for 5 min and an electromyography signal was acquired for 15 min with no treatment (control group). [Results] In the treatment group, the median frequency shifted to a higher level; the root mean square decreased over time, and then maintained a minimum amplitude. However, there were few changes in the electromyography signal after exercise in the control group. [Conclusion] Electromyography signals can provide information about the effective duration for muscle fatigue treatment as well as the muscle characteristics during treatment. This study should be helpful for clinicians by demonstrating the appropriate duration of therapy for relief of muscle stiffness.

  14. Perspective of surface active agents in baking industry: an overview.

    Science.gov (United States)

    Ahmad, Asif; Arshad, Nazish; Ahmed, Zaheer; Bhatti, Muhammad Shahbaz; Zahoor, Tahir; Anjum, Nomana; Ahmad, Hajra; Afreen, Asma

    2014-01-01

    Different researchers have previously used surfactants for improving bread qualities and revealed that these compounds result in improving the quality of dough and bread by influencing dough strength, tolerance, uniform crumb cell size, and improve slicing characteristics and gas retention. The objective of this review is to highlight the areas where surfactants are most widely used particularly in the bread industries, their role and mechanism of interaction and their contribution to the quality characteristics of the dough and bread. This review reveals some aspects of surface-active agents regarding its role physiochemical properties of dough that in turn affect the bread characteristics by improving its sensory quality and storage stability.

  15. Molluscicidal properties and selective toxicity of surface-active agents

    Science.gov (United States)

    Visser, S. A.

    1965-01-01

    Of over 100 commercially produced surface-active agents tested against the bilharziasis vector snail Biomphalaria sudanica, 13 were found to possess considerable and highly selective molluscicidal properties at concentrations of less than 1 ppm for exposures of 48 hours. Against crustacea, fish, water plants, mosquito larvae, mice, and the eggs of B. sudanica, the toxicities of the 13 surfactants were slight. The chemicals did not appear to be absorbed by organic matter to any appreciable extent. It is thought that the toxicity to B. sudanica is of both a chemical and a physical nature. PMID:5294185

  16. Design and development of an automated, portable and handheld tablet personal computer-based data acquisition system for monitoring electromyography signals during rehabilitation.

    Science.gov (United States)

    Ahamed, Nizam U; Sundaraj, Kenneth; Poo, Tarn S

    2013-03-01

    This article describes the design of a robust, inexpensive, easy-to-use, small, and portable online electromyography acquisition system for monitoring electromyography signals during rehabilitation. This single-channel (one-muscle) system was connected via the universal serial bus port to a programmable Windows operating system handheld tablet personal computer for storage and analysis of the data by the end user. The raw electromyography signals were amplified in order to convert them to an observable scale. The inherent noise of 50 Hz (Malaysia) from power lines electromagnetic interference was then eliminated using a single-hybrid IC notch filter. These signals were sampled by a signal processing module and converted into 24-bit digital data. An algorithm was developed and programmed to transmit the digital data to the computer, where it was reassembled and displayed in the computer using software. Finally, the following device was furnished with the graphical user interface to display the online muscle strength streaming signal in a handheld tablet personal computer. This battery-operated system was tested on the biceps brachii muscles of 20 healthy subjects, and the results were compared to those obtained with a commercial single-channel (one-muscle) electromyography acquisition system. The results obtained using the developed device when compared to those obtained from a commercially available physiological signal monitoring system for activities involving muscle contractions were found to be comparable (the comparison of various statistical parameters) between male and female subjects. In addition, the key advantage of this developed system over the conventional desktop personal computer-based acquisition systems is its portability due to the use of a tablet personal computer in which the results are accessible graphically as well as stored in text (comma-separated value) form.

  17. Effects of Hydrotherapy on postural control and electromyography parameters in men with chronic non-specific low back pain

    Directory of Open Access Journals (Sweden)

    Mahdi Mahjur

    2016-05-01

    Full Text Available The aim of this study was to evaluate effects of hydrotherapy on postural control and electromyography parameters in men with chronic non-specific low back pain. Thirty men with chronic non-specific LBP divided into two hydrotherapy and control groups, randomly and equally. Electromyographic activity of erector spinae muscles and balance measured for both of groups before and after intervention. Hydrotherapy program was consisted of 24 sessions. Subjects in control group didn’t have any special activity. Two-way variance was used to interpret the data and correlated and independent T-tests were used for analysis of data at the significance level of (P0.05. However, a significant difference observed between two groups in balance index (P<0.05.

  18. In vitro study of proteins surface activity by tritium probe

    International Nuclear Information System (INIS)

    Chernysheva, M.G.; Badun, G.A.

    2010-01-01

    A new technique for in vitro studies of biomacromolecules interactions, their adsorption at aqueous/organic liquid interfaces and distribution in the bulk of liquid/liquid systems was developed. The method includes (1) tritium labeling of biomolecules by tritium thermal activation method and (2) scintillation phase step with organic phase, which can be concerned as a model of cellular membrane. Two globular proteins lysozyme and human serum albumin tested. We have determined the conditions of tritium labeling when labeled by-products can be easy separated by means of dialysis and size-exclusion chromatography. Scintillation phase experiments were conducted for three types of organic liquids. Thus, the influences of the nature of organic phase on proteins adsorption and its distribution in the bulk of aqueous/organic liquid system were determined. It was found that proteins possess high surface activity at aqueous/organic liquid interface. Furthermore, values of hydrophobicity of globular proteins were found by the experiment. (author)

  19. Exotic high activity surface patterns in PtAu nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-05-09

    The structure and chemical ordering of PtAu nanoclusters of 79, 135, and 201 atoms are studied via a combination of a basin hopping atom-exchange technique (to locate the lowest energy homotops at fixed composition), a symmetry orbit technique (to find the high symmetry isomers), and density functional theory local reoptimization (for determining the most stable homotop). The interatomic interactions between Pt and Au are derived from the empirical Gupta potential. The lowest energy structures show a marked tendency toward PtcoreAushell chemical ordering by enrichment of the more cohesive Pt in the core region and of Au in the shell region. We observe a preferential segregation of Pt atoms to (111) facets and Au atoms to (100) facets of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active sites. © 2013 American Chemical Society.

  20. Fatigue effects upon sticking region and electromyography in a six-repetition maximum bench press.

    Science.gov (United States)

    van den Tillaar, Roland; Saeterbakken, Atle Hole

    2013-01-01

    The aim of the study was to examine the sticking region and concomitant neuromuscular activation of the prime movers during six-repetition maximum (RM) bench pressing. We hypothesised that both peak velocities would decrease and that the electromyography (EMG) of the prime movers (deltoid, major pectoralis and triceps) would increase during the pre-sticking and sticking region during the six repetitions due to fatigue. Thirteen resistance-trained males (age 22.8 ± 2.2 years, stature 1.82 ± 0.06 m, body mass 83.4 ± 7.6 kg) performed 6-RM bench presses. Barbell kinematics and EMG activity of pectoralis major, deltoid anterior, and triceps brachii during the pre-, sticking and post-sticking region of each repetition in a 6-RM bench press were analysed. For both the sticking as the post-sticking region, the time increased significantly from the first to the sixth repetition. Vertical barbell height at the start of sticking region was lower, while the height at the end of the sticking region and post-sticking region did not change during the six repetitions. It was concluded that in 6-RM bench pressing performance, the sticking region is a poor mechanical force region due to the unchanged barbell height at the end of the sticking region. Furthermore, when fatigue occurs, the pectoralis and the deltoid muscles are responsible for surpassing the sticking region as indicated by their increased activity during the pre- and sticking region during the six-repetitions bench press.

  1. Normalisation method can affect gluteus medius electromyography results during weight bearing exercises in people with hip osteoarthritis (OA): a case control study.

    Science.gov (United States)

    French, Helen P; Huang, Xiaoli; Cummiskey, Andrew; Meldrum, Dara; Malone, Ailish

    2015-02-01

    Surface electromyography (sEMG) is used to assess muscle activation during therapeutic exercise, but data are significantly affected by inter-individual variability and requires normalisation of the sEMG signal to enable comparison between individuals. The purpose of this study was to compare two normalisation methods, a maximal method (maximum voluntary isometric contraction (MVIC)) and non-maximal peak dynamic method (PDM), on gluteus medius (GMed) activation using sEMG during three weight-bearing exercises in people with hip osteoarthritis (OA) and healthy controls. Thirteen people with hip OA and 20 controls performed three exercises (Squat, Step-Up, Step-Down). Average root-mean squared EMG amplitude based on MVIC and PDM normalisation was compared between groups for both involved and uninvolved hips using Mann-Whitney tests. Using MVIC normalisation, significantly higher normalised GMed EMG amplitudes were found in the OA group during all Step-up and down exercises on the involved side (p=0.02-0.001) and most of the Step exercises on the uninvolved side (p=0.03-0.04), but not the Squat (p>0.05), compared to controls. Using PDM normalisation, significant between-group differences occurred only for Ascending Squat (p=0.03) on the involved side. MVIC normalisation demonstrated higher inter-trial relative reliability (ICCs=0.78-0.99) than PDM (ICCs=0.37-0.84), but poorer absolute reliability using Standard Error of Measurement. Normalisation method can significantly affect interpretation of EMG amplitudes. Although MVIC-normalised amplitudes were more sensitive to differences between groups, there was greater variability using this method, which raises concerns regarding validity. Interpretation of EMG data is strongly influenced by the normalisation method used, and this should be considered when applying EMG results to clinical populations. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. The Ice Nucleation Activity of Surface Modified Soot

    Science.gov (United States)

    Häusler, Thomas; Witek, Lorenz; Felgitsch, Laura; Hitzenberger, Regina; Grothe, Hinrich

    2017-04-01

    The ice nucleation efficiency of many important atmospheric particles remains poorly understood. Since soot is ubiquitous in the Earth's troposphere, they might have the potential to significantly impact the Earth's climate (Finlayson-Pitts and Pitts, 2000; Seinfeld and Pandis, 1998). Here we present the ice nucleation activity (INA) in immersion freezing mode of different types of soot. Therefor a CAST (combustion aerosol standard) generator was used to produce different kinds of soot samples. The CAST generator combusts a propane-air-mixture and deposits thereby produced soot on a polyvinyl fluoride filter. By varying the propane to air ratio, the amount of organic portion of the soot can be varied from black carbon (BC) with no organic content to brown carbon (BrC) with high organic content. To investigate the impact of functional sites of ice nuclei (IN), the soot samples were exposed to NO2 gas for a certain amount of time (30 to 360 minutes) to chemically modify the surface. Immersion freezing experiments were carried out in a unique reaction gadget. In this device a water-in-oil suspension (with the soot suspended in the aqueous phase) was cooled till the freezing point and was observed through a microscope (Pummer et al., 2012; Zolles et al., 2015) It was found that neither modified nor unmodified BC shows INA. On the contrary, unmodified BrC shows an INA at -32˚ C, which can be increased up to -20˚ C. The INA of BrC depends on the duration of NO2- exposure. To clarify the characteristics of the surface modifications, surface sensitive analysis like infrared spectroscopy and X-ray photoelectron spectroscopy were carried out. Finlayson-Pitts, B. J. and Pitts, J. N. J.: Chemistry of the Upper and Lower Atmosphere, Elsevier, New York, 2000. Pummer, B. G., Bauer, H., Bernardi, J., Bleicher, S., and Grothe, H.: Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen, Atmos Chem Phys, 12, 2541-2550, 2012. Seinfeld, J

  3. Controlled release of biologically active silver from nanosilver surfaces.

    Science.gov (United States)

    Liu, Jingyu; Sonshine, David A; Shervani, Saira; Hurt, Robert H

    2010-11-23

    Major pathways in the antibacterial activity and eukaryotic toxicity of nanosilver involve the silver cation and its soluble complexes, which are well established thiol toxicants. Through these pathways, nanosilver behaves in analogy to a drug delivery system, in which the particle contains a concentrated inventory of an active species, the ion, which is transported to and released near biological target sites. Although the importance of silver ion in the biological response to nanosilver is widely recognized, the drug delivery paradigm has not been well developed for this system, and there is significant potential to improve nanosilver technologies through controlled release formulations. This article applies elements of the drug delivery paradigm to nanosilver dissolution and presents a systematic study of chemical concepts for controlled release. After presenting thermodynamic calculations of silver species partitioning in biological media, the rates of oxidative silver dissolution are measured for nanoparticles and macroscopic foils and used to derive unified area-based release kinetics. A variety of competing chemical approaches are demonstrated for controlling the ion release rate over 4 orders of magnitude. Release can be systematically slowed by thiol and citrate ligand binding, formation of sulfidic coatings, or the scavenging of peroxy-intermediates. Release can be accelerated by preoxidation or particle size reduction, while polymer coatings with complexation sites alter the release profile by storing and releasing inventories of surface-bound silver. Finally, the ability to tune biological activity is demonstrated through a bacterial inhibition zone assay carried out on selected formulations of controlled release nanosilver.

  4. Neck Kinematics and Electromyography While Wearing Head Supported Mass During Running.

    Science.gov (United States)

    Hanks, Matthew M; Sefton, JoEllen M; Oliver, Gretchen D

    2018-01-01

    Advanced combat helmets (ACH) coupled with night-vision goggles (NVG) are required for tactical athletes during training and service. Head and neck injuries due to head supported mass (HSM) are a common occurrence in military personnel. The current study aimed to investigate the effects of HSM on neck muscle fatigue that may lead to chronic stress and injury of the head and neck. Subjects wore an ACH and were affixed with electromagnetic sensors to obtain kinematic data, as well as EMG electrodes to obtain muscle activations of bilateral sternocleidomastoid, upper trapezius, and paraspinal muscles while running on a treadmill. Subjects performed a 2-min warmup at a walking pace, a 5-min warmup jog, running at a pace equal to 90% maximum heart rate until absolute fatigue, and lastly a 2-min cooldown at a walking pace. Kinematic and EMG data were collected over each 2-min interval. Days later, the same subjects wore the same ACH in addition to the NVG and performed the same protocol as the first session. This study showed significant differences in muscle activation of the right upper trapezius [F(1,31) = 10.100] and both sternocleidomastoid [F(1,31) = 12.280] muscles from pre-fatigue to absolute fatigue. There were no significant differences noted in the kinematic variables. This study suggests that HSM can fatigue bilateral neck flexors and rotators, as well as fatigue the neck extensors and rotators on the contralateral side of the mounted NVG.Hanks MM, Sefton JM, Oliver GD. Neck kinematics and electromyography while wearing head supported mass during running. Aerosp Med Hum Perform. 2018; 89(1):9-13.

  5. Active-site titration analysis of surface influence on immobilized Candida antarctica Lipase B activity

    Science.gov (United States)

    Matrix morphology and surface polarity effects were investigated for Candida antarctica lipase B immobilization. Measurements of the amount of lipase immobilized (bicinchoninic acid method) and the catalyst’s tributyrin hydrolysis activity, coupled with a determination of the lipase’s functional fr...

  6. Covalent organic polymer functionalization of activated carbon surfaces through acyl chloride for environmental clean-up

    DEFF Research Database (Denmark)

    Mines, Paul D.; Thirion, Damien; Uthuppu, Basil

    2017-01-01

    Nanoporous networks of covalent organic polymers (COPs) are successfully grafted on the surfaces of activated carbons, through a series of surface modification techniques, including acyl chloride formation by thionyl chloride. Hybrid composites of activated carbon functionalized with COPs exhibit...

  7. Mechanical stress-controlled tunable active frequency-selective surface

    Science.gov (United States)

    Huang, Bo-Cin; Hong, Jian-Wei; Lo, Cheng-Yao

    2017-01-01

    This study proposes a tunable active frequency-selective surface (AFSS) realized by mechanically expanding or contracting a split-ring resonator (SRR) array. The proposed AFSS transfers mechanical stress from its elastic substrate to the top of the SRR, thereby achieving electromagnetic (EM) modulation without the need for an additional external power supply, meeting the requirements for the target application: the invisibility cloak. The operating mechanism of the proposed AFSS differs from those of other AFSSs, supporting modulations in arbitrary frequencies in the target range. The proposed stress-controlled or strain-induced EM modulation proves the existence of an identical and linear relationship between the strain gradient and the frequency shift, implying its suitability for other EM modulation ranges and applications.

  8. Self-activated, self-limiting reactions on Si surfaces

    DEFF Research Database (Denmark)

    Morgen, Per; Hvam, Jeanette; Bahari, Ali

    , and the temperatures vary from room temperature to 10000C.The growth is in these cases self-limiting, with the optimal oxide thickness around 0.7-0.8 nm, at 5000C, and up to a few nm for nitride. The self-limiting oxide case was recently predicted by Alex Demkov in a structural optimization to minimise the total...... energy of an oxide system, which happened for an ordered structure, at a thickness of 0.7-0.8 nm. Thus this thin oxide structure has definite crystalline features. We have closely monitored the reaction kinetics with normal x-ray induced photoelectron spectroscopies, and also the structure, composition...... and electrical properties of the system, with surface sensitive, high resolution core level photoelectron spectroscopy. The growth kinetics is well fitted by a Hill function, with parameters, which give information about the character of the process. This function describes a self-activated process. Thus...

  9. A novel broadband bi-mode active frequency selective surface

    Science.gov (United States)

    Xu, Yang; Gao, Jinsong; Xu, Nianxi; Shan, Dongzhi; Song, Naitao

    2017-05-01

    A novel broadband bi-mode active frequency selective surface (AFSS) is presented in this paper. The proposed structure is composed of a periodic array of convoluted square patches and Jerusalem Crosses. According to simulation results, the frequency response of AFSS definitely exhibits a mode switch feature between band-pass and band-stop modes when the diodes stay in ON and OFF states. In order to apply a uniform bias to each PIN diode, an ingenious biasing network based on the extension of Wheatstone bridge is adopted in prototype AFSS. The test results are in good agreement with the simulation results. A further physical mechanism of the bi-mode AFSS is shown by contrasting the distribution of electric field on the AFSS patterns for the two working states.

  10. A novel broadband bi-mode active frequency selective surface

    Directory of Open Access Journals (Sweden)

    Yang Xu

    2017-05-01

    Full Text Available A novel broadband bi-mode active frequency selective surface (AFSS is presented in this paper. The proposed structure is composed of a periodic array of convoluted square patches and Jerusalem Crosses. According to simulation results, the frequency response of AFSS definitely exhibits a mode switch feature between band-pass and band-stop modes when the diodes stay in ON and OFF states. In order to apply a uniform bias to each PIN diode, an ingenious biasing network based on the extension of Wheatstone bridge is adopted in prototype AFSS. The test results are in good agreement with the simulation results. A further physical mechanism of the bi-mode AFSS is shown by contrasting the distribution of electric field on the AFSS patterns for the two working states.

  11. Improved efficiency of budesonide nebulization using surface-active agents.

    Science.gov (United States)

    Bouwman, A M; Heijstra, M P; Schaefer, N C; Duiverman, E J; Lesouëf, P N; Devadason, S G

    2006-01-01

    Our aim was to improve the efficiency of nebulised budesonide using surface-active agents. Cationic, anionic, and nonionic detergents were added to commercial budesonide suspension, and the particle size distribution during nebulization was measured using both cascade impaction and laser diffraction. Our results showed that the emitted dose was increased after addition of cationic (p < 0.001) and nonionic detergents (p < 0.01) compared with the commercial formulation alone. The respirable fraction was increased for all detergent formulations (p < 0.001) compared with the commercial formulation. We concluded that cationic and nonionic detergent increased the total output of budesonide from the Sidestream. All detergent formulations increased the respirable fraction of nebulized budesonide.

  12. Relative activity of respiratory muscles during prescribed inspiratory muscle training in healthy people

    OpenAIRE

    Jung, Ju-hyeon; Kim, Nan-soo

    2016-01-01

    [Purpose] This study aimed to determine the effects of different intensities of inspiratory muscle training on the relative respiratory muscle activity in healthy adults. [Subjects and Methods] Thirteen healthy male volunteers were instructed to perform inspiratory muscle training (0%, 40%, 60%, and 80% maximal inspiratory pressure) on the basis of their individual intensities. The inspiratory muscle training was performed in random order of intensities. Surface electromyography data were col...

  13. How the condition of occlusal support affects the back muscle force and masticatory muscle activity?

    OpenAIRE

    石岡, 克; 河野, 正司; Ishioka, Masaru; Kohno, Shoji

    2002-01-01

    This study was conducted to determine how the condition of occlusal support affects the back muscle force and masticatory muscle activity. Two groups of subjects were enlisted: sport-trained group and normal group. While electrodes of the electromyography (EMG) were attached to the surface of the masticatory muscles, each subject's back muscle force was recorded during upper body stretching using a back muscle force-measuring device. The task was performed under four different occlusal suppor...

  14. The Research of Phase Retrieval Holography Method Based on the Active Deformation of the Active Reflector Surface

    Science.gov (United States)

    Wang, Z. Q.; Chen, M. Z.; Pei, X.; Wang, J.

    2017-09-01

    The surface accuracy of a large reflector radio telescope is one of the important factors influencing the performance of the antenna. The effects of panel processing, installation, as well as gravity, temperature, and wind load, will greatly limit the observation efficiency of the antenna. Focused on the technology of active surface which is more accurately controllable than the minor reflector surface of six-ploe, the continuous distribution of active deformation phase factor described by Zernike polynomials is adopted for the first time. Only getting the far field amplitude through adjusting the active surface, the surface error can be detected. By building the models of numerical simulation, the retrieval error of arbitrary surface deformation is calculated, and the retrieval results of surface deformation in a variety of continuous active surface deformation is also studied. It is indicated that this method can stably and accurately detect surface deformation, and can also improve the efficiency of radio telescope observations effectively.

  15. Effects of breathing maneuver and sitting posture on muscle activity in inspiratory accessory muscles in patients with chronic obstructive pulmonary disease

    OpenAIRE

    Kim, Ki-song; Byun, Min-kwang; Lee, Won-hwee; Cynn, Heon-seock; Kwon, Oh-yun; Yi, Chung-hwi

    2012-01-01

    Abstract Background To determine the influence of breathing maneuver and sitting posture on tidal volume (TV), respiratory rate (RR), and muscle activity of the inspiratory accessory muscles in patients with chronic obstructive pulmonary disease (COPD). Methods Twelve men with COPD participated in the study. Inductive respiratory plethysmography and surface electromyography were used to simultaneously measure TV, RR, and muscle activity of the inspiratory accessory muscles [the scalenus (SM),...

  16. Lower motor neuron involvement examined by quantitative electromyography in amyotrophic lateral sclerosis

    DEFF Research Database (Denmark)

    Krarup, Christian

    2011-01-01

    Objective The diagnosis of amyotrophic lateral sclerosis (ALS) includes demonstration of lower motor neuron (LMN) and upper motor neuron (UMN) involvement of bulbar and spinal muscles. Electromyography (EMG) is essential to confirm LMN affection in weak muscles, and to demonstrate changes...

  17. A trial fabrication of activity standard surface sources and positional standard surface sources for an imaging plate system

    International Nuclear Information System (INIS)

    Sato, Yasushi; Hino, Yoshio; Yamada, Takahiro; Matsumoto, Mikio

    2003-01-01

    An imaging plate system can detect low level activity, but quantitative analysis is difficult because there are no adequate standard surface sources. A new fabrication method was developed for standard surface sources by printing on a sheet of paper using an ink-jet printer with inks in which a radioactive material was mixed. The fabricated standard surface sources had high uniformity, high positional resolution arbitrary shapes and a broad intensity range. The standard sources were used for measurement of surface activity as an application. (H. Yokoo)

  18. Occurrence of Surface Active Agents in the Environment

    Directory of Open Access Journals (Sweden)

    Ewa Olkowska

    2014-01-01

    Full Text Available Due to the specific structure of surfactants molecules they are applied in different areas of human activity (industry, household. After using and discharging from wastewater treatment plants as effluent stream, surface active agents (SAAs are emitted to various elements of the environment (atmosphere, waters, and solid phases, where they can undergo numerous physic-chemical processes (e.g., sorption, degradation and freely migrate. Additionally, SAAs present in the environment can be accumulated in living organisms (bioaccumulation, what can have a negative effect on biotic elements of ecosystems (e.g., toxicity, disturbance of endocrine equilibrium. They also cause increaseing solubility of organic pollutants in aqueous phase, their migration, and accumulation in different environmental compartments. Moreover, surfactants found in aerosols can affect formation and development of clouds, which is associated with cooling effect in the atmosphere and climate changes. The environmental fate of SAAs is still unknown and recognition of this problem will contribute to protection of living organisms as well as preservation of quality and balance of various ecosystems. This work contains basic information about surfactants and overview of pollution of different ecosystems caused by them (their classification and properties, areas of use, their presence, and behavior in the environment.

  19. A novel estimating method for steering efficiency of the driver with electromyography signals

    Science.gov (United States)

    Liu, Yahui; Ji, Xuewu; Hayama, Ryouhei; Mizuno, Takahiro

    2014-05-01

    The existing research of steering efficiency mainly focuses on the mechanism efficiency of steering system, aiming at designing and optimizing the mechanism of steering system. In the development of assist steering system especially the evaluation of its comfort, the steering efficiency of driver physiological output usually are not considered, because this physiological output is difficult to measure or to estimate, and the objective evaluation of steering comfort therefore cannot be conducted with movement efficiency perspective. In order to take a further step to the objective evaluation of steering comfort, an estimating method for the steering efficiency of the driver was developed based on the research of the relationship between the steering force and muscle activity. First, the steering forces in the steering wheel plane and the electromyography (EMG) signals of the primary muscles were measured. These primary muscles are the muscles in shoulder and upper arm which mainly produced the steering torque, and their functions in steering maneuver were identified previously. Next, based on the multiple regressions of the steering force and EMG signals, both the effective steering force and the total force capacity of driver in steering maneuver were calculated. Finally, the steering efficiency of driver was estimated by means of the estimated effective force and the total force capacity, which represented the information of driver physiological output of the primary muscles. This research develops a novel estimating method for driver steering efficiency of driver physiological output, including the estimation of both steering force and the force capacity of primary muscles with EMG signals, and will benefit to evaluate the steering comfort with an objective perspective.

  20. Does Heel Height Cause Imbalance during Sit-to-Stand Task: Surface EMG Perspective

    Directory of Open Access Journals (Sweden)

    Ganesh R. Naik

    2017-08-01

    Full Text Available The purpose of this study was to determine whether electromyography (EMG muscle activities around the knee differ during sit-to-stand (STS and returning task for females wearing shoes with different heel heights. Sixteen healthy young women (age = 25.2 ± 3.9 years, body mass index = 20.8 ± 2.7 kg/m2 participated in this study. Electromyography signals were recorded from the two muscles, vastus medialis (VM and vastus lateralis (VL that involve in the extension of knee. The participants wore shoes with five different heights, including 4, 6, 8, 10, and 12 cm. Surface electromyography (sEMG data were acquired during STS and stand-to-sit-returning (STSR tasks. The data was filtered using a fourth order Butterworth (band pass filter of 20–450 Hz frequency range. For each heel height, we extracted median frequency (MDF and root mean square (RMS features to measure sEMG activities between VM and VL muscles. The experimental results (based on MDF and RMS-values indicated that there is imbalance between vasti muscles for more elevated heels. The results are also quantified with statistical measures. The study findings suggest that there would be an increased likelihood of knee imbalance and fatigue with regular usage of high heel shoes (HHS in women.

  1. Assessing the Antimicrobial Activity of Polyisoprene Based Surfaces

    Directory of Open Access Journals (Sweden)

    Hope Badawy

    2015-02-01

    Full Text Available There has been an intense research effort in the last decades in the field of biofouling prevention as it concerns many aspects of everyday life and causes problems to devices, the environment, and human health. Many different antifouling and antimicrobial materials have been developed to struggle against bacteria and other micro- and macro-organism attachment to different surfaces. However the “miracle solution” has still to be found. The research presented here concerns the synthesis of bio-based polymeric materials and the biological tests that showed their antifouling and, at the same time, antibacterial activity. The raw material used for the coating synthesis was natural rubber. The polyisoprene chains were fragmented to obtain oligomers, which had reactive chemical groups at their chain ends, therefore they could be modified to insert polymerizable and biocidal groups. Films were obtained by radical photopolymerization of the natural rubber derived oligomers and their structure was altered, in order to understand the mechanism of attachment inhibition and to increase the efficiency of the anti-biofouling action. The adhesion of three species of pathogenic bacteria and six strains of marine bacteria was studied. The coatings were able to inhibit bacterial attachment by contact, as it was verified that no detectable leaching of toxic molecules occurred.

  2. Immunoadjuvant activity of the nanoparticles’ surface modified with mannan

    Science.gov (United States)

    Haddadi, Azita; Hamdy, Samar; Ghotbi, Zahra; Samuel, John; Lavasanifar, Afsaneh

    2014-09-01

    Mannan (MN) is the natural ligand for mannose receptors, which are widely expressed on dendritic cells (DCs). The purpose of this study was to assess the effect of formulation parameters on the immunogenicity of MN-decorated poly (D, L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) in terms of their ability to stimulate DC phenotypic as well as functional maturation. For this purpose, NPs were formulated from either ester-terminated or COOH-terminated PLGA. Incorporation of MN in NPs was achieved through encapsulation, physical adsorption or chemical conjugation. Murine bone marrow derived DCs (BMDCs) were treated with various NP formulations and assessed for their ability to up-regulate DC cell surface markers, secrete immunostimulatory cytokines and to activate allogenic T cell responses. DCs treated with COOH-terminated PLGA-NPs containing chemically conjugated MN (MN-Cov-COOH) have shown superior performance in improving DC biological functions, compared to the rest of the formulations tested. This may be attributed to the higher level of MN incorporation in the former formulation. Incorporation of MN in PLGA NPs through chemical conjugation can lead to enhanced DC maturation and stimulatory function. This strategy may be used to develop more effective PLGA-based vaccine formulations.

  3. Gait electromyography in children with myelomeningocele at the sacral level.

    Science.gov (United States)

    Park, B K; Song, H R; Vankoski, S J; Moore, C A; Dias, L S

    1997-05-01

    Patients with sacral level myelomeningocele can be expected to maintain a high level of ambulatory status long into adulthood. Gait deterioration and knee pain reported in this population may be attributed to compensatory movements and increased recruitment of less affected muscle groups to achieve this desired level of ambulation. The objective of this study was to analyze the effect of the solid ankle-foot-orthoses (AFOs) on the muscular activity of selected muscles during walking. Cohort/outcome. Laboratory. Twenty four patients with sacral level myelomeningocele between 4 to 17 years of age. Electromyographic activity of selected muscle groups were studied during barefoot walking and walking with solid AFOs at a self-selected walking velocity. Timing of electromyographic activity and sagittal plane knee kinematics. Comparison to normal electromyographic patterns and changes between barefoot and AFO walking conditions. With the AFOs there was significantly less prolonged stance phase quadriceps activity compared with barefoot walking, although greater than normal activity persisted. There was no change between conditions for the other monitored muscle groups. All muscles elicited greater duration of activity over the course of the gait cycle. Our results show that solid AFOs improve the prolonged knee extensor activity evident for barefoot walking. This is clinically relevant to the gait deterioration and knee pain sometimes seen in this patient population. We espouse early and persistent orthotic intervention to reduce compensatory muscular overactivity and maintain gait quality.

  4. Evidence of antibacterial activity on titanium surfaces through nanotextures

    Science.gov (United States)

    Seddiki, O.; Harnagea, C.; Levesque, L.; Mantovani, D.; Rosei, F.

    2014-07-01

    Nosocomial infections (Nis) are a major concern for public health. As more and more of the pathogens responsible for these infections are antibiotic resistant, finding new ways to overcome them is a major challenge for biomedical research. We present a method to reduce Nis spreading by hindering bacterial adhesion in its very early stage. This is achieved by reducing the contact interface area between the bacterium and the surface by nanoengineering the surface topography. In particular, we studied the Escheria Coli adhesion on titanium surfaces exhibiting different morphologies, that were obtained by a combination of mechanical polishing and chemical etching. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization revealed that the titanium surface is modified at both micro- and nano-scale. X-ray Photoelectron Spectroscopy (XPS) revealed that the surfaces have the same composition before and after piranha treatment, consisting mainly of TiO2. Adhesion tests showed a significant reduction in bacterial accumulation on nanostructured surfaces that had the lowest roughness over large areas. SEM images acquired after bacterial culture on different titanium substrates confirmed that the polished titanium surface treated one hour in a piranha solution at a temperature of 25 °C has the lowest bacterial accumulation among all the surfaces tested. This suggests that the difference observed in bacterial adhesion between the different surfaces is due primarily to surface topography.

  5. Evidence of antibacterial activity on titanium surfaces through nanotextures

    International Nuclear Information System (INIS)

    Seddiki, O.; Harnagea, C.; Levesque, L.; Mantovani, D.; Rosei, F.

    2014-01-01

    Nosocomial infections (Nis) are a major concern for public health. As more and more of the pathogens responsible for these infections are antibiotic resistant, finding new ways to overcome them is a major challenge for biomedical research. We present a method to reduce Nis spreading by hindering bacterial adhesion in its very early stage. This is achieved by reducing the contact interface area between the bacterium and the surface by nanoengineering the surface topography. In particular, we studied the Escheria Coli adhesion on titanium surfaces exhibiting different morphologies, that were obtained by a combination of mechanical polishing and chemical etching. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization revealed that the titanium surface is modified at both micro- and nano-scale. X-ray Photoelectron Spectroscopy (XPS) revealed that the surfaces have the same composition before and after piranha treatment, consisting mainly of TiO 2 . Adhesion tests showed a significant reduction in bacterial accumulation on nanostructured surfaces that had the lowest roughness over large areas. SEM images acquired after bacterial culture on different titanium substrates confirmed that the polished titanium surface treated one hour in a piranha solution at a temperature of 25 °C has the lowest bacterial accumulation among all the surfaces tested. This suggests that the difference observed in bacterial adhesion between the different surfaces is due primarily to surface topography.

  6. Evidence of antibacterial activity on titanium surfaces through nanotextures

    Energy Technology Data Exchange (ETDEWEB)

    Seddiki, O.; Harnagea, C. [INRS – Centre Énergie, Matériaux et Télécommunications, Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2 (Canada); Levesque, L.; Mantovani, D. [Laboratory for Biomaterials and Bioengineering (CRC-I), Dept Min-Met-Materials Engineering and Research Center CHU-Quebec, Laval University, Quebec City (Canada); Rosei, F., E-mail: rosei@emt.inrs.ca [INRS – Centre Énergie, Matériaux et Télécommunications, Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2 (Canada); Center for Self-Assembled Chemical Structures, McGill University, H3A 2K6 Montreal, Quebec (Canada)

    2014-07-01

    Nosocomial infections (Nis) are a major concern for public health. As more and more of the pathogens responsible for these infections are antibiotic resistant, finding new ways to overcome them is a major challenge for biomedical research. We present a method to reduce Nis spreading by hindering bacterial adhesion in its very early stage. This is achieved by reducing the contact interface area between the bacterium and the surface by nanoengineering the surface topography. In particular, we studied the Escheria Coli adhesion on titanium surfaces exhibiting different morphologies, that were obtained by a combination of mechanical polishing and chemical etching. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization revealed that the titanium surface is modified at both micro- and nano-scale. X-ray Photoelectron Spectroscopy (XPS) revealed that the surfaces have the same composition before and after piranha treatment, consisting mainly of TiO{sub 2}. Adhesion tests showed a significant reduction in bacterial accumulation on nanostructured surfaces that had the lowest roughness over large areas. SEM images acquired after bacterial culture on different titanium substrates confirmed that the polished titanium surface treated one hour in a piranha solution at a temperature of 25 °C has the lowest bacterial accumulation among all the surfaces tested. This suggests that the difference observed in bacterial adhesion between the different surfaces is due primarily to surface topography.

  7. Electromyography and nerve conduction velocity for the evaluation of the infraspinatus muscle and the suprascapular nerve in professional beach volleyball players.

    Science.gov (United States)

    Lajtai, Georg; Wieser, Karl; Ofner, Michael; Raimann, Gustav; Aitzetmüller, Gernot; Jost, Bernhard

    2012-10-01

    Beach volleyball is an overhead sport with a high prevalence of infraspinatus muscle atrophy of the hitting shoulder. Infraspinatus muscle atrophy seems to be caused by a repetitive traction injury of the suprascapular nerve. Early pathological findings might be assessed with surface electromyography (EMG) and nerve conduction velocity (NCV) measurements. Cross-sectional study; Level of evidence, 3. Fully competitive professional beach volleyball players were assessed with a structured interview, shoulder examination, strength measurements (external rotation and elevation), and neurophysiological examination (surface EMG and NCV of the infraspinatus and supraspinatus muscles and the suprascapular nerve, respectively) during the Beach Volleyball Grand Slam tournament 2010 in Klagenfurt, Austria. Thirty-five men with an average age of 28 years were examined. Visible infraspinatus atrophy was found in 12 players (34%), of which 8 (23%) had slight atrophy and 4 (11%) had severe atrophy. External rotation (90%; P volleyball players have a high frequency of infraspinatus atrophy (34%) and significantly reduced shoulder strength of the hitting shoulder. These findings are not associated with demographic factors. Electromyography and NCV measurements suggest a suprascapular nerve involvement caused by repetitive strain injuries of the nerve. External rotation strength measurements and NCV measurements can detect a side-to-side difference early, while EMG may show compensation mechanisms for progressive damaging of the suprascapular nerve and, as a result, loss of infraspinatus muscle strength.

  8. Understanding the effect of steps, strain, poisons, and alloying: Methane activation on Ni surfaces

    DEFF Research Database (Denmark)

    Abild-Pedersen, Frank; Greeley, Jeffrey Philip; Nørskov, Jens Kehlet

    2005-01-01

    that variations in epsilon(d) can be used to quantitatively describe variations in the activation energy when the surface structure is changed, when the coverage of carbon is changed, when the surface is strained, when the surface is alloyed, and when the surface is poisoned by sulfur. The d-band center is...

  9. Surface activity and molecular characteristics of cuttlefish skin gelatin modified by oxidized linoleic acid

    NARCIS (Netherlands)

    Aewsiri, T.; Benjakul, S.; Visessanguan, W.; Wierenga, P.A.; Gruppen, H.

    2011-01-01

    Surface activity and molecular changes of cuttlefish skin gelatin modified with oxidized linoleic acid (OLA) prepared at 60, 70 and 80 °C at different times were investigated. Modification of gelatin with OLA could improve surface activity of resulting gelatin as evidenced by the decreased surface

  10. Morphology and optical properties of aluminum oxide formed into oxalic electrolyte with addition surface active agents

    International Nuclear Information System (INIS)

    Kazarkin, B; Stsiapanau, A; Smirnov, A; Zhilinski, V; Chernik, A; Bezborodov, V; Kozak, G; Danilovich, S

    2016-01-01

    The article discusses the results of investigations of porous films of alumina, formed into oxalic electrolyte with addition surface active agents, in particular, ordering structure, roughness of a surface, the optical transparency of the electrolyte concentration and surface active agents. Also discusses the features of the formation of porous films of temperature and IR radiation. (paper)

  11. Operational Estimates of Surface Albedo, Vegetation Photosynthetic Activity and Surface Structure: An Overview of the GVM/SAI Activities

    Science.gov (United States)

    Verstraete, M. M.; Pinty, B.; Gobron, N.; Widlowski, J.

    2001-05-01

    The GVM Unit of the SAI derives reliable, accurate, quantitative information on the state and evolution of the biosphere from remote sensing data, using state of the art techniques. This information is provided to various services of the European Commission in support of the verification of compliance with national and international treaties, protocols and conventions, and to the scientific community in the framework of defined collaborations. Estimates of land surface albedo have been obtained from an analysis of monospectral but multiangular observations from the geostationary Meteosat platform. An analysis of these results has shown the continental scale impact of human activities (in particular biomass burning over large areas). An extension of this approach to the more advanced Meteosat Second Generation platform, to be launched in 2002, will yield more and better products. High performance yet very fast algorithms have been derived to optimally assess the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) of live green vegetation, which largely controls the productivity of plants and therefore their ability to sequester atmospheric carbon dioxide. These algorithms, typically used with multispectral but monoangular sensors such as AVHRR, SeaWiFS, or VEGETATION, have now been further developed to take advantage of the high spatial resolution or multiangular views offered by modern sensors such as the MISR on NASA's Terra platform. Recent advances in radiation transfer modeling and scientific collaborations with the cloud community have opened new vistas on the possibility of characterizing the structure of ecosystems a the sub-pixel scale on the basis of multiangular data, and may lead to improved land cover classifications and new applications.

  12. Substrate integrated ferrite phase shifters and active frequency selective surfaces

    International Nuclear Information System (INIS)

    Cahill, B.M.

    2002-01-01

    There are two distinct parts to this thesis; the first investigates the use of ferrite tiles in the construction of printed phase shifting transmission lines, culminating in the design of two compact electromagnetic controlled beam steered patch and slot antenna arrays. The second part investigates the use of active frequency selective surfaces (AFSS), which are later used to cover a uPVC constructed enclosure. Field intensity measurements are taken from within the enclosure to determine the dynamic screening effectiveness. Trans Tech G-350 Ferrite is investigated to determine its application in printed microstrip and stripline phase shifting transmission lines. 50-Ohm transmission lines are constructed using the ferrite tile and interfaced to Rogers RT Duroid 5870 substrate. Scattering parameter measurements are made under the application of variable magnetic fields to the ferrite. Later, two types of planar microwave beam steering antennas are constructed. The first uses the ferrites integrated into the Duroid as microstrip lines with 3 patch antennas as the radiating elements. The second uses stripline transmission lines, with slot antennas as the radiating sources etched into the ground plane of the triplate. Beam steering is achieved by the application of an external electromagnet. An AFSS is constructed by the interposition of PIN diodes into a dipole FSS array. Transmission response measurements are then made for various angles of electromagnetic wave incidence. Two states of operation exist: when a current is passed through the diodes and when the diodes are switched off. These two states form a high pass and band stop space filter respectively. An enclosure covered with the AFSS is constructed and externally illuminated in the range 2.0 - 2.8GHz. A probe antenna inside the enclosure positioned at various locations through out the volume is used to establish the effective screening action of the AFSS in 3 dimensional space. (author)

  13. Surface and interface electronic structure: Sixth year activity report

    International Nuclear Information System (INIS)

    Kevan, S.D.

    1992-01-01

    Several productive runs were made on beamline U4A at NSLS. An upgrade of angle-resolved photoemission spectrometer was largely completed on the beamline. Progress was made on studies of surface states and reconstruction on Mo(001) and W(001), and of surface states and resonances on Pt(111)

  14. Gluteus medius and thigh muscles electromyography during load carrying walking

    Directory of Open Access Journals (Sweden)

    Petr Šťastný

    2015-11-01

    Full Text Available This study compares the electromyographic (EMG peak amplitude changes of gluteus medius (Gmed, vastus medialis (VMO, vastus lateralis (VL and biceps femoris (BF during load carrying walking due to the increased load. The percentage of maximum isometric voluntary contractions (%MVIC of both limbs and 3D kinematic of lower limbs were detected on eighteen resistance-trained men (mean age ± SD, 31 ± 3.4 years while carrying loads of 25, 50 and 75% of their body mass (BM. The repeated measurement ANOVA was used to evaluate the differences in muscles %MVIC and 3D kinematics at all load conditions. Significant differences were found for Gmed %MVIC (F3,99 = 19.8, p < 0.001. Gmed activity was significantly different between load carrying walking with 25% of BM (mean ± SD, 20 ± 12%MVIC, 50% of BM (32 ± 17%MVIC and 75% of BM (45 ± 26%MVIC condition. Differences were found in hip flexion at Gmed EMG peak (F3,96 = 14, p < 0.001, between 25% of BM (18 ± 11° and 50% of BM (29 ± 7°. No significant differences were found for thigh muscles, when thigh muscle activity did not exceed 30%MVIC even at 75% of BM condition. Load carrying walking is an exercise which activates Gmed more than thigh muscles. This exercise increases the Gmed activity along with increased loads and it should be regarded as a complex Gmed strengthening exercise. This exercise is recommended for strengthening the Gmed with low activation of VL and VMO.

  15. A Krebs Cycle Component Limits Caspase Activation Rate through Mitochondrial Surface Restriction of CRL Activation.

    Science.gov (United States)

    Aram, Lior; Braun, Tslil; Braverman, Carmel; Kaplan, Yosef; Ravid, Liat; Levin-Zaidman, Smadar; Arama, Eli

    2016-04-04

    How cells avoid excessive caspase activity and unwanted cell death during apoptotic caspase-mediated removal of large cellular structures is poorly understood. We investigate caspase-mediated extrusion of spermatid cytoplasmic contents in Drosophila during spermatid individualization. We show that a Krebs cycle component, the ATP-specific form of the succinyl-CoA synthetase β subunit (A-Sβ), binds to and activates the Cullin-3-based ubiquitin ligase (CRL3) complex required for caspase activation in spermatids. In vitro and in vivo evidence suggests that this interaction occurs on the mitochondrial surface, thereby limiting the source of CRL3 complex activation to the vicinity of this organelle and reducing the potential rate of caspase activation by at least 60%. Domain swapping between A-Sβ and the GTP-specific SCSβ (G-Sβ), which functions redundantly in the Krebs cycle, show that the metabolic and structural roles of A-Sβ in spermatids can be uncoupled, highlighting a moonlighting function of this Krebs cycle component in CRL activation. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Unobtrusive electromyography-based eating detection in daily life: A new tool to address underreporting?

    Science.gov (United States)

    Blechert, J; Liedlgruber, M; Lender, A; Reichenberger, J; Wilhelm, F H

    2017-11-01

    Research on eating behavior is limited by an overreliance on self-report. It is well known that actual food intake is frequently underreported, and it is likely that this problem is overrepresented in vulnerable populations. The present research tested a chewing detection method that could assist self-report methods. A trained sample of 15 participants (usable data of 14 participants) kept detailed eating records during one day and one night while carrying a recording device. Signals recorded from electromyography sensors unobtrusively placed behind the right ear were used to develop a chewing detection algorithm. Results showed that eating could be detected with high accuracy (sensitivity, specificity >90%) compared to trained self-report. Thus, electromyography-based eating detection might usefully complement future food intake studies in healthy and vulnerable populations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Use of electromyography to detect muscle exhaustion in finishing barrows fed ractopamine HCl.

    Science.gov (United States)

    Noel, J A; Broxterman, R M; McCoy, G M; Craig, J C; Phelps, K J; Burnett, D D; Vaughn, M A; Barstow, T J; O'Quinn, T G; Woodworth, J C; DeRouchey, J M; Rozell, T G; Gonzalez, J M

    2016-06-01

    The objectives of this study were to determine the effects of dietary ractopamine HCl (RAC) on muscle fiber characteristics and electromyography (EMG) measures of finishing barrow exhaustion when barrows were subjected to increased levels of activity. Barrows ( = 34; 92 ± 2 kg initial BW) were assigned to 1 of 2 treatments: a conventional swine finishing diet containing 0 mg/kg ractopamine HCl (CON) or a diet formulated to meet the requirements of finishing barrows fed 10 mg/kg RAC (RAC+). After 32 d on feed, barrows were individually moved around a track at 0.79 m/s until subjectively exhausted. Wireless EMG sensors were affixed to the deltoideus (DT), triceps brachii lateral head (TLH), tensor fasciae latae (TFL), and semitendinosus (ST) muscles to measure median power frequency (MdPF) and root mean square (RMS) as indicators of action potential conduction velocity and muscle fiber recruitment, respectively. After harvest, samples of each muscle were collected for fiber type, succinate dehydrogenase (SDH), and capillary density analysis. Speed was not different ( = 0.82) between treatments, but RAC+ barrows reached subjective exhaustion earlier and covered less distance than CON barrows ( 0.29). There was a treatment × muscle interaction ( = 0.04) for end-point RMS values. The RAC diet did not change end-point RMS values in the DT or TLH ( > 0.37); however, the diet tended to decrease and increase end-point RMS in the ST and TFL, respectively ( 0.10). Muscles of RAC+ barrows tended to have less type I fibers and more capillaries per fiber ( < 0.07). Type I and IIA fibers of RAC+ barrows were larger ( < 0.07). Compared with all other muscles, the ST had more ( < 0.01) type IIB fibers and larger type I, IIA, and IIX fibers ( < 0.01). Type I, IIA, and IIX fibers of the ST also contained less SDH compared with the other muscles ( < 0.01). Barrows fed a RAC diet had increased time to subjective exhaustion due to loss of active muscle fibers in the ST, possibly due

  18. A Biomechanical Comparison of Proportional Electromyography Control to Biological Torque Control Using a Powered Hip Exoskeleton.

    Science.gov (United States)

    Young, Aaron J; Gannon, Hannah; Ferris, Daniel P

    2017-01-01

    Despite a large increase in robotic exoskeleton research, there are few studies that have examined human performance with different control strategies on the same exoskeleton device. Direct comparison studies are needed to determine how users respond to different types of control. The purpose of this study was to compare user performance using a robotic hip exoskeleton with two different controllers: a controller that targeted a biological hip torque profile and a proportional myoelectric controller. We tested both control approaches on 10 able-bodied subjects using a pneumatically powered hip exoskeleton. The state machine controller targeted a biological hip torque profile. The myoelectric controller used electromyography (EMG) of lower limb muscles to produce a proportional control signal for the hip exoskeleton. Each subject performed two 30-min exoskeleton walking trials (1.0 m/s) using each controller and a 10-min trial with the exoskeleton unpowered. During each trial, we measured subjects' metabolic cost of walking, lower limb EMG profiles, and joint kinematics and kinetics (torques and powers) using a force treadmill and motion capture. Compared to unassisted walking in the exoskeleton, myoelectric control significantly reduced metabolic cost by 13% ( p  = 0.005) and biological hip torque control reduced metabolic cost by 7% ( p  = 0.261). Subjects reduced muscle activity relative to the unpowered condition for a greater number of lower limb muscles using myoelectric control compared to the biological hip torque control. More subjects subjectively preferred the myoelectric controller to the biological hip torque control. Myoelectric control had more advantages (metabolic cost and muscle activity reduction) compared to a controller that targeted a biological torque profile for walking with a robotic hip exoskeleton. However, these results were obtained with a single exoskeleton device with specific control configurations while level walking at a

  19. A Biomechanical Comparison of Proportional Electromyography Control to Biological Torque Control Using a Powered Hip Exoskeleton

    Directory of Open Access Journals (Sweden)

    Aaron J. Young

    2017-06-01

    Full Text Available BackgroundDespite a large increase in robotic exoskeleton research, there are few studies that have examined human performance with different control strategies on the same exoskeleton device. Direct comparison studies are needed to determine how users respond to different types of control. The purpose of this study was to compare user performance using a robotic hip exoskeleton with two different controllers: a controller that targeted a biological hip torque profile and a proportional myoelectric controller.MethodsWe tested both control approaches on 10 able-bodied subjects using a pneumatically powered hip exoskeleton. The state machine controller targeted a biological hip torque profile. The myoelectric controller used electromyography (EMG of lower limb muscles to produce a proportional control signal for the hip exoskeleton. Each subject performed two 30-min exoskeleton walking trials (1.0 m/s using each controller and a 10-min trial with the exoskeleton unpowered. During each trial, we measured subjects’ metabolic cost of walking, lower limb EMG profiles, and joint kinematics and kinetics (torques and powers using a force treadmill and motion capture.ResultsCompared to unassisted walking in the exoskeleton, myoelectric control significantly reduced metabolic cost by 13% (p = 0.005 and biological hip torque control reduced metabolic cost by 7% (p = 0.261. Subjects reduced muscle activity relative to the unpowered condition for a greater number of lower limb muscles using myoelectric control compared to the biological hip torque control. More subjects subjectively preferred the myoelectric controller to the biological hip torque control.ConclusionMyoelectric control had more advantages (metabolic cost and muscle activity reduction compared to a controller that targeted a biological torque profile for walking with a robotic hip exoskeleton. However, these results were obtained with a single exoskeleton device with specific

  20. Surface EMG of the masticatory muscles (part 2): fatigue testing, mastication analysis and influence of different factors.

    Science.gov (United States)

    Hugger, S; Schindler, H J; Kordass, B; Hugger, A

    2013-01-01

    The second part of this review of the literature on the clinical significance of surface electromyography (EMG) of the masticatory muscles systematically examines the results of clinical studies in patients with temporomandibular disorders (TMD), preferably randomized controlled trials, investigating relevant aspects of EMG activity during prolonged chewing activity (fatigue effects), during the mastication process, and under the influence of different factors. Studies on the influence of factors such as gender, age, tooth status, orofacial morphology and (acute) pain, the significance of different occlusal relationships during static and dynamic occlusion, and the impact of changes in static occlusion on EMG activity of the masticatory muscles were included in the review.

  1. Improvement of silicon direct bonding using surfaces activated by hydrogen plasma treatment

    CERN Document Server

    Choi, W B; Lee Jae Sik; Sung, M Y

    2000-01-01

    The plasma surface treatment, using hydrogen gas, of silicon wafers was studied as a pretreatment for silicon direct bonding. Chemical reactions of the hydrogen plasma with the surfaces were used for both surface activation and removal of surface contaminants. Exposure of the silicon wafers to the plasma formed an active oxide layer on the surface. This layer was hydrophilic. The surface roughness and morphology were examined as functions of the plasma exposure time and power. The surface became smoother with shorter plasma exposure time and lower power. In addition, the plasma surface treatment was very efficient in removing the carbon contaminants on the silicon surface. The value of the initial surface energy, as estimated by using the crack propagation method, was 506 mJ/M sup 2 , which was up to about three times higher than the value for the conventional direct bonding method using wet chemical treatments.

  2. Chemical surface tuning electrocatalysis of redox-active nanoparticles

    DEFF Research Database (Denmark)

    Zhu, Nan; Ulstrup, Jens; Chi, Qijin

    This work focuses on electron transfer (ET) and electrocatalysis of inorganic hybrid Prussian blue nanoparticles (PBNPs, 6 nm) immobilized on different chemical surfaces. Through surface self-assembly chemistry, we have enabled to tune chemical properties of the electrode surface. Stable immobili......This work focuses on electron transfer (ET) and electrocatalysis of inorganic hybrid Prussian blue nanoparticles (PBNPs, 6 nm) immobilized on different chemical surfaces. Through surface self-assembly chemistry, we have enabled to tune chemical properties of the electrode surface. Stable...... PBNPs are characterized by atomic force microscopy (AFM). Reversible electron transfer (ET) was detected by cyclic voltammetry (CV) of the PBNPs on all the surfaces. ET kinetics can be controlled by adjusting the chain length of the SAMs. The rate constants are found to depend exponentially on the ET...... distance, with a decay factor (β) of ca. 0.9, 1.1, 1.3 per CH2, respectively. This feature suggests a tunneling mechanism adopted by the nanoparticles, resembling that for metalloproteins in a similar assembly. High-efficient electrocatalysis towards the reduction of H2O2 is observed, and possible...

  3. Electromyography function, disability degree, and pain in leprosy patients undergoing neural mobilization treatment

    Directory of Open Access Journals (Sweden)

    Larissa Sales Téles Véras

    2012-02-01

    Full Text Available INTRODUCTION: This study aimed to evaluate the effect of the neural mobilization technique on electromyography function, disability degree, and pain in patients with leprosy. METHODS: A sample of 56 individuals with leprosy was randomized into an experimental group, composed of 29 individuals undergoing treatment with neural mobilization, and a control group of 27 individuals who underwent conventional treatment. In both groups, the lesions in the lower limbs were treated. In the treatment with neural mobilization, the procedure used was mobilization of the lumbosacral roots and sciatic nerve biased to the peroneal nerve that innervates the anterior tibial muscle, which was evaluated in the electromyography. RESULTS: Analysis of the electromyography function showed a significant increase (p<0.05 in the experimental group in both the right (Δ%=22.1, p=0.013 and the left anterior tibial muscles (Δ%=27.7, p=0.009, compared with the control group pre- and post-test. Analysis of the strength both in the movement of horizontal extension (Δ%right=11.7, p=0.003/Δ%left=27.4, p=0.002 and in the movement of back flexion (Δ%right=31.1; p=0.000/Δ%left=34.7, p=0.000 showed a significant increase (p<0.05 in both the right and the left segments when comparing the experimental group pre- and post-test. The experimental group showed a significant reduction (p=0.000 in pain perception and disability degree when the pre- and post-test were compared and when compared with the control group in the post-test. CONCLUSIONS: Leprosy patients undergoing the technique of neural mobilization had an improvement in electromyography function and muscle strength, reducing disability degree and pain.

  4. Muscle-fiber conduction velocity and electromyography as diagnostic tools in patients with suspected inflammatory myopathy: a prospective study.

    NARCIS (Netherlands)

    Blijham, P.J.; Hengstman, G.J.D.; Laak, H.J. ter; Engelen, B.G.M. van; Zwarts, M.J.

    2004-01-01

    Combinations of different techniques can increase the diagnostic yield from neurophysiological examination of muscle. In 25 patients with suspected inflammatory myopathy, we prospectively performed needle electromyography (EMG) and measured muscle-fiber conduction velocity (MFCV) in a single muscle,

  5. An Investigation Into Time Domain Features of Surface Electromyography to Estimate the Elbow Joint Angle

    Directory of Open Access Journals (Sweden)

    Triwiyanto Triwiyanto

    2017-01-01

    Full Text Available In literature, it is well established that feature extraction and pattern classification algorithms play essential roles in accurate estimation of the elbow joint angle. The problem with these algorithms, however, is that they require a learning stage to recognize the pattern as well as capture the variability associated with every subject when estimating the elbow joint angle. As EMG signals can be used to represent motion, we developed a non-pattern recognition method to estimate the elbow joint angle based on twelve time-domain features extracted from EMG signals recorded from bicep muscles alone. The extracted features were smoothed using a second order Butterworth low pass filter to produce the estimation. The accuracy of the estimated angles was evaluated by using the Pearson’s Correlation Coefficient (PCC and Root Mean Square Error (RMSE.The regression parameters (Euclidean distance, R^2 and slope were calculated to observe the response of the features to the elbow-joint angle. From the investigation, we found, in the period of motion 10s, MYOP features have the best accuracy: 0.97±0.02 (Mean±SD and 11.37±3.04˚ (Mean±SD for correlation coefficient and RMSE respectively. MYOP features also showed the highest R^2 and slope value 0.986±0.0083 (Mean±SD and 0.746±0.17 (Mean±SD respectively for flexion and extension motion and all periods of motion.

  6. Detection and Alert of muscle fatigue considering a Surface Electromyography Chaotic Model

    International Nuclear Information System (INIS)

    Herrera, V; Romero, J F; Amestegui, M

    2011-01-01

    This work propose a detection and alert algorithm for muscle fatigue in paraplegic patients undergoing electro-therapy sessions. The procedure is based on a mathematical chaotic model emulating physiological signals and Continuous Wavelet Transform (CWT). The chaotic model developed is based on a logistic map that provides suitable data accomplishing some physiological signal class patterns. The CWT was applied to signals generated by the model and the resulting vector was obtained through Total Wavelet Entropy (TWE). In this sense, the presented work propose a viable and practical alert and detection algorithm for muscle fatigue.

  7. Detection and Alert of muscle fatigue considering a Surface Electromyography Chaotic Model

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, V; Romero, J F [Engineering, Modeling and Applied Social Sciences Center, ABC Federal University, Santo Andr - SP (Brazil); Amestegui, M, E-mail: victoria.herrera@ufabc.edu.br [Engineering Faculty, Electronics Engineering, Universidad Mayor de San Andres, La Paz (Bolivia, Plurinational State of)

    2011-03-01

    This work propose a detection and alert algorithm for muscle fatigue in paraplegic patients undergoing electro-therapy sessions. The procedure is based on a mathematical chaotic model emulating physiological signals and Continuous Wavelet Transform (CWT). The chaotic model developed is based on a logistic map that provides suitable data accomplishing some physiological signal class patterns. The CWT was applied to signals generated by the model and the resulting vector was obtained through Total Wavelet Entropy (TWE). In this sense, the presented work propose a viable and practical alert and detection algorithm for muscle fatigue.

  8. Surface electromyography in diagnosis of lateral dominance in children: psychomotor aspects

    OpenAIRE

    Jordy, Ceme Ferreira [UNIFESP

    1995-01-01

    A dominância lateral foi verificada pelo eletromiograma de superfície em 100 crianças neurologicamente normais. Foram usados estímulos verbais durante os registros eletromiográficos. Em comparação com o diagnóstico clínico, a eletromiografia se revelou mais precisa, excluindo influências subjetivas nos resultados. Destrismo foi diagnosticado em 90 pacientes, canhotismo em 3 e dominância indefinida em 7. Mecanismos de ordem psicomotora são sugeridos para justificar as respostas motoras provoca...

  9. Diagnosis of cauda equina abnormalities by using electromyography, discography, and epidurography in dogs

    International Nuclear Information System (INIS)

    Sisson, A.F.; LeCouteur, R.A.; Ingram, J.T.; Park, R.D.; Child, G.

    1992-01-01

    Electromyography (EMG), L7-S1 discography and epidurography were investigated in 15 dogs with clinical signs of cauda equina dysfunction and in 7 control dogs without such clinical signs. Electromyography of paraspinal and pelvic limb muscles was done in 13 of 15 affected dogs. An L7-S1 discogram followed by an epidurogram was performed in all 22 dogs using 20% iopamidol. Results of discograms, epidurograms, and gross necropsy examinations were normal in six of seven control dogs. The one dog in which these studies were abnormal had a mild L7-S1 disc protrusion that did not result in nerve root compression at necropsy. Electromyographic analysis was 100% accurate in predicting the presence or absence of cauda equina disease. None of the results of discograms were falsely negative. Twelve of 15 discograms in clinically affected dogs indicated dorsal disc protrusion, but 2 of these protrusions were found to be noncompressive at surgery (13% error). Abnormal epidurograms occurred in 9 of 15 clinically affected dogs. There was one false positive and two false negatives (20% error). Electromyography was a sensitive screening technique for the presence of cauda equina disease. Discography may be more sensitive for detection of L7-S1 disc protrusion than epidurography. An abnormal radiographic contrast study of the cauda equina may only be useful when combined with an abnormal EMG

  10. Protecting Surface Transportation Systems and Patrons from Terrorist Activities

    Science.gov (United States)

    1997-11-01

    This report documents the first phase of a continuing research effort carried out by the Norman Y. Mineta International Institute for Surface Transportation Policy Studies (IISTPS) on behalf of the U.S. Department of Transportation. It comprises a ch...

  11. Magnetic activity at Mars - Mars Surface Magnetic Observatory

    DEFF Research Database (Denmark)

    Vennerstrøm, Susanne; Menvielle, M.; Merayo, José M.G.

    2012-01-01

    We use the extensive database of magnetic observations from the Mars Global Surveyor to investigate magnetic disturbances in the Martian space environment statistically, both close to and far from crustal anomalies. We discuss the results in terms of possible ionospheric and magnetospheric currents...... a magnetic experiment at the martian surface, the Mars Surface Magnetic Observatory (MSMO) including the science objectives, science experiment requirements, instrument and basic operations. We find the experiment to be feasible within the constraints of proposed stationary landing platforms....

  12. Nature of the Elimination of the Penicillinase Plasmid from Staphylococcus aureus by Surface-Active Agents

    Science.gov (United States)

    Sonstein, Stephen A.; Baldwin, J. N.

    1972-01-01

    Growth of Stapylococcus aureus in various ionic surface-active agents resulted in loss of the ability to produce penicillinase, whereas growth in nonionic surface-active agents had no effect on penicillinase production. The curing effect of various alkyl sulfates was found to be dependent upon the chain length. Curing by surface-active agents could be inhibited by magnesium. Reciprocal transduction experiments showed that curing by a surface-active agent was a property of the plasmid, not of the bacterial strain in which the plasmic resides. PMID:4204903

  13. [Electromyography Analysis of Rapid Eye Movement Sleep Behavior Disorder].

    Science.gov (United States)

    Nakano, Natsuko; Kinoshita, Fumiya; Takada, Hiroki; Nakayama, Meiho

    2018-01-01

    Polysomnography (PSG), which records physiological phenomena including brain waves, breathing status, and muscle tonus, is useful for the diagnosis of sleep disorders as a gold standard. However, measurement and analysis are complex for several specific sleep disorders, such as rapid eye movement (REM) sleep behavior disorder (RBD). Usually, brain waves during REM sleep indicate an awakening pattern under relaxed conditions of skeletal and antigravity muscles. However, these muscles are activated during REM sleep when patients suffer from RBD. These activated muscle movements during REM, so-called REM without atonia (RWA) recorded by PSG, may be related to a neurodegenerative disease such as Parkinson's disease. Thus, careful analysis of RWA is significant not only physically, but also clinically. Commonly, manual viewing measurement analysis of RWA is time-consuming. Therefore, quantitative studies on RWA are rarely reported. A software program, developed from Microsoft Office Excel ® , was used to semiautomatically analyze the RWA ratio extracted from PSG to compare with manual viewing measurement analysis. In addition, a quantitative muscle tonus study was carried out to evaluate the effect of medication on RBD patients. Using this new software program, we were able to analyze RWA on the same cases in approximately 15 min as compared with 60 min in the manual viewing measurement analysis. This software program can not only quantify RWA easily but also identify RWA waves for either phasic or tonic bursts. We consider that this software program will support physicians and scientists in their future research on RBD. We are planning to offer this software program for free to physicians and scientists.

  14. Effect of enzymatic hydrolysis on surface activity and surface rheology of type I collagen.

    Science.gov (United States)

    Kezwoń, Aleksandra; Chromińska, Ilona; Frączyk, Tomasz; Wojciechowski, Kamil

    2016-01-01

    We describe the adsorption behaviour and rheological properties of a calf skin type I collagen, and of its hydrolysates obtained using a Clostridium histolyticum collagenase (CHC) under moderate conditions (pH 7, 37°C). The effect of CHC concentration (2×10(-9)-2×10(-6)M) and incubation time (35-85min) was studied and optimised to achieve the highest decrease of surface tension and the highest dilational surface viscoelasticity of the adsorbed layers. SDS-PAGE electrophoresis and reverse-phase high performance liquid chromatography (RP-HPLC) were used to characterise the hydrolysis products. The results show that even simple modifications (heat treatment, pH change, partial hydrolysis) of collagen enhances its surface properties, especially in terms of surface dilational elasticity modulus. The use of low enzyme concentration (CHC-to-collagen molar ratio of 4×10(-3)) and short incubation time (<45min) results in moderately hydrolysed products with the highest ability to lower surface tension (γ=53.9mNm(-1)) forming highly elastic adsorbed layers (surface dilational elasticity, E'=74.5mNm(-1)). Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Influence of activated carbon characteristics on toluene and hexane adsorption: Application of surface response methodology

    Science.gov (United States)

    Izquierdo, Mª Teresa; de Yuso, Alicia Martínez; Valenciano, Raquel; Rubio, Begoña; Pino, Mª Rosa

    2013-01-01

    The objective of this study was to evaluate the adsorption capacity of toluene and hexane over activated carbons prepared according an experimental design, considering as variables the activation temperature, the impregnation ratio and the activation time. The response surface methodology was applied to optimize the adsorption capacity of the carbons regarding the preparation conditions that determine the physicochemical characteristics of the activated carbons. The methodology of preparation produced activated carbons with surface areas and micropore volumes as high as 1128 m2/g and 0.52 cm3/g, respectively. Moreover, the activated carbons exhibit mesoporosity, ranging from 64.6% to 89.1% the percentage of microporosity. The surface chemistry was characterized by TPD, FTIR and acid-base titration obtaining different values of surface groups from the different techniques because the limitation of each technique, but obtaining similar trends for the activated carbons studied. The exhaustive characterization of the activated carbons allows to state that the measured surface area does not explain the adsorption capacity for either toluene or n-hexane. On the other hand, the surface chemistry does not explain the adsorption results either. A compromise between physical and chemical characteristics can be obtained from the appropriate activation conditions, and the response surface methodology gives the optimal activated carbon to maximize adsorption capacity. Low activation temperature, intermediate impregnation ratio lead to high toluene and n-hexane adsorption capacities depending on the activation time, which a determining factor to maximize toluene adsorption.

  16. comparison of sorption capacity and surface area of activated

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. Activated carbons were prepared from fruit pericarp and seed coat of Jatropha curcas using. KOH and NaCl as activating agents leading to the production of four samples of activated carbons JPS, JPP, JCS and JCP. The adsorption capacity based on adsorption of methylene blue was determined for each ...

  17. The influence of the leaf gauge and anterior jig on jaw muscle electromyography and condylar head displacement: a pilot study.

    Science.gov (United States)

    Santosa, R E; Azizi, M; Whittle, T; Wanigaratrne, K; Klineberg, I J

    2006-03-01

    A leaf gauge and an anterior jig may be used to assist the recording of a reproducible jaw position for restorative and prosthodontic treatment. This study investigated possible condylar displacement using an opto-electronic jaw-tracking device and a leaf gauge or anterior jig. The effect of a leaf gauge and anterior jig on jaw muscle electromyography was also examined. Five healthy adults without symptoms of temporomandibular disorders were selected. Condylar displacement during clenching were recorded simultaneously with electromyographic activity of superior and inferior heads of the lateral pterygoid, anterior and posterior temporalis, masseter, and suprahyoid muscles. Subjects were trained to bite at maximum and half-maximum bite-force using an anterior jig incorporating a force transducer. No consistent condylar displacement was observed in x, y and z axes between different bite-forces although there was a trend towards superior displacement. Comparison of maximum intercuspal clench and maximum clench on a leaf gauge and an anterior jig produced significant decrease in anterior temporalis activity (p jig with maximum clench significantly decreased posterior temporalis muscle activity. Within the limits of this pilot study, no consistent change in condylar position was identified with these appliances.

  18. Using of the surface activation method for enhancement of machine realibility

    International Nuclear Information System (INIS)

    Postnikov, V.I.; Garbar, I.N.

    1979-01-01

    A surface activation method is described for controlling the wear of units and details, allowing one to measure the wear at continuous operation of the mechanism by any program. The main advantages of the surface activation method for the wear tests are shown. By means of that method it was possible to develop a simultaneous controlling conjugate detail wear, and a method of different-activity brands, as well as the method for repeated activation of details. Development of theory for the engineering and technology of engine wear control by the surface activation method allowed one to improve the efficiency and reduce the time of research in the field of friction and wear

  19. Surface plasmon polariton modulator with optimized active layer

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Lavrinenko, Andrei

    2012-01-01

    A multilayered waveguide, which supports surface plasmon polaritons, is considered as an absorption modulator. The waveguide core consists of a silicon nitride layer and ultrathin layer with the varied carrier density embedded between two silver plates, which also serve as electrodes. Under apply...

  20. Diagnostic accuracy of the electromyography parameters associated with anterior knee pain in the diagnosis of patellofemoral pain syndrome.

    Science.gov (United States)

    Ferrari, Deisi; Kuriki, Heloyse Uliam; Silva, Cristiano Rocha; Alves, Neri; Mícolis de Azevedo, Fábio

    2014-08-01

    To assess the diagnostic accuracy of the surface electromyography (sEMG) parameters associated with referred anterior knee pain in diagnosing patellofemoral pain syndrome (PFPS). Sensitivity and specificity analysis. Physical rehabilitation center and laboratory of biomechanics and motor control. Pain-free subjects (n=29) and participants with PFPS (n=22) selected by convenience. Not applicable. The diagnostic accuracy was calculated for sEMG parameters' reliability, precision, and ability to differentiate participants with and without PFPS. The selected sEMG parameter associated with anterior knee pain was considered as an index test and was compared with the reference standard for the diagnosis of PFPS. Intraclass correlation coefficient, SEM, independent t tests, sensitivity, specificity, negative and positive likelihood ratios, and negative and positive predictive values were used for the statistical analysis. The medium-frequency band (B2) parameter was reliable (intraclass correlation coefficient=.80-.90), precise (SEM=2.71-3.87 normalized unit), and able to differentiate participants with and without PFPS (Ppain showed positive diagnostic accuracy values (specificity, .87; sensitivity, .70; negative likelihood ratio, .33; positive likelihood ratio, 5.63; negative predictive value, .72; and positive predictive value, .86). The results provide evidence to support the use of EMG signals (B2-frequency band of 45-96 Hz) of the vastus lateralis and vastus medialis muscles with referred anterior knee pain in the diagnosis of PFPS. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  1. Neuromuscular functions in sportsmen and fibromyalgia patients : a surface EMG study in static and dynamic conditions

    NARCIS (Netherlands)

    Klaver-Krol, E.G.

    2012-01-01

    This thesis presents two studies, one involving sportsmen (sprinters versus endurance athletes) and one fibromyalgia patients (patients versus healthy controls). The studies have investigated muscular functions using a non-invasive method: surface electromyography (sEMG). In the sportsmen,

  2. Comparison of sorption capacity and surface area of activated ...

    African Journals Online (AJOL)

    Ash content and percentage fixed carbon were determined for two of the activated carbons (JPS and JCS) with the highest adsorptive capacity. Equilibrium study on adsorption was carried out and the adsorption data were analyzed using the Langmuir isotherm. The results obtained indicate that activated carbons from the ...

  3. Bismuth Ferrite for Active Control of Surface Plasmon Polariton Modes

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Zhukovsky, Sergei; Lavrinenko, Andrei

    2014-01-01

    We propose and investigate several layouts of m etal-insulator-metal waveguide with active core which can be utilized for dynamic switching in photonic integrated circuits. The active material, bismuth ferrite (BiFeO3), is sandwiched between metal plates and changes i ts refractive index through...

  4. Analysis of applied forces and electromyography of back and shoulders muscles when performing a simulated hand scaling task.

    Science.gov (United States)

    Porter, William; Gallagher, Sean; Torma-Krajewski, Janet

    2010-05-01

    Hand scaling is a physically demanding task responsible for numerous overexertion injuries in underground mining. Scaling requires the miner to use a long pry bar to remove loose rock, reducing the likelihood of rock fall injuries. The experiments described in this article simulated "rib" scaling (scaling a mine wall) from an elevated bucket to examine force generation and electromyographic responses using two types of scaling bars (steel and fiberglass-reinforced aluminum) at five target heights ranging from floor level to 176 cm. Ten male and six female subjects were tested in separate experiments. Peak and average force applied at the scaling bar tip and normalized electromyography (EMG) of the left and right pairs of the deltoid and erectores spinae muscles were obtained. Work height significantly affected peak prying force during scaling activities with highest force capacity at the lower levels. Bar type did not affect force generation. However, use of the lighter fiberglass bar required significantly more muscle activity to achieve the same force. Results of these studies suggest that miners scale points on the rock face that are below their knees, and reposition the bucket as often as necessary to do so. Published by Elsevier Ltd.

  5. A proposed definition of the 'activity' of surface sites on lactose carriers for dry powder inhalation

    NARCIS (Netherlands)

    Grasmeijer, Floris; Frijlink, Henderik W.; de Boer, Anne

    2014-01-01

    A new definition of the activity of surface sites on lactose carriers for dry powder inhalation is proposed which relates to drug detachment during dispersion. The new definition is expected to improve the understanding of 'carrier surface site activity', which stimulates the unambiguous

  6. Developments of a bonding technique for optical materials by a surface activation method

    International Nuclear Information System (INIS)

    Sugiyama, Akira; Oda, Tomohiro; Abe, Tomoyuki; Kusunoki, Isao

    2005-01-01

    We started developing the laser crystal bounding by the surface activation method which can splice crystals together without using hydrogen bonding. For the surface activation, neutral argon beams were used for irradiation of specimens. In the bonding trials with sapphire crystals, we recognized possibility of the bonding method for optical elements. (author)

  7. Monitoring RAYT activity by surface plasmon resonance biosensor

    Czech Academy of Sciences Publication Activity Database

    Bocková, Markéta; Špringer, Tomáš; Nečasová, Iva; Nunvář, Jaroslav; Schneider, Bohdan; Homola, Jiří

    2015-01-01

    Roč. 407, č. 14 (2015), s. 3985-3993 ISSN 1618-2642 R&D Projects: GA ČR GAP305/12/1801 Grant - others:GA MŠk(CZ) CZ.1.05/1.1.00/02.0109 Institutional support: RVO:67985882 ; RVO:86652036 Keywords : Surface plasmon resonance * Biosensor * REP-associated tyrosine transposase Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering; EB - Genetics ; Molecular Biology (BTO-N) Impact factor: 3.125, year: 2015

  8. THE EFFECTS OF RARE EARTHS ON ACTIVITY AND SURFACE ...

    African Journals Online (AJOL)

    higher the temperature of H2O desorption is, the stronger the Ru−OH2 bond at the surface of the catalysts and the greater the dissociation of H2O become. The shift reaction needs the dissociative of adsorption H2O to break OH−H and O−H bonds. Therefore the increase of the adsorbing intensity of H2O is associated with ...

  9. Surface-Activated Amorphous Alloy Fuel Electrodes for Methanol Fuel Cell

    OpenAIRE

    Asahi, Kawashima; Koji, Hashimoto; The Research Institute for Iron, Steel and Other Metals; The Research Institute for Iron, Steel and Other Metals

    1983-01-01

    Amorphous alloy electrodes for electrochemical oxidation of methanol and its derivatives were obtained by the surface activation treatment consisting of electrodeposition of zinc on as-quenched amorphous alloy substrates, heating at 200-300℃ for 30 min, and subsequently leaching of zinc in an alkaline solution. The surface activation treatment provided a new method for the preparation of a large surface area on the amorphous alloys. The best result for oxidation of methanol, sodium formate an...

  10. Study of the processes of adsorption of amine-containing surface-active substance on the surface of Aluminum powder

    Directory of Open Access Journals (Sweden)

    Antonina Dyuryagina

    2012-03-01

    Full Text Available Equilibrium characteristics of adsorption on a surface of a pigment depending on concentration factors and temperature of the dispersive environment are defined. Kinetic laws of superficial activity of binary, threefold homogeneous and heterogeneous modeling systems are studied. The estimation of mechanisms of process of adsorption is carried out.

  11. Stability of thin liquid films containing surface active particles

    Science.gov (United States)

    Umashankar, Hariharan; Kalpathy, Sreeram; Dixit, Harish

    2017-11-01

    The stability and dynamics of thin liquid films(industrial settings like coating and printing processes and extraction of oil from porous rocks. In this study a hydrodynamic model is introduced to capture the long term evolution of a Newtonian liquid film containing insoluble surfaceactive particles.We consider here the possibility of four distinct interaction regimes based on the surface rheological effects of the particles, such that either, both or neither of Marangoni and surface viscosity effects would be present at the leading order in the governing equations. The liquid film is bounded by a rigid impermeable solid below and covered by passive air phase above.A standard linear stability analysis and nonlinear simulations are performed on the set of highly coupled partial differential evolution equations. Linear stability analysis gives insights on whether a particular imposed perturbationwavenumber will grow or decay in time and also evaluating the fastest growing wavenumber. Parametric studies for all four regimes provides a strong confirmation that surface viscosity and Marangoni effects are indeed rupture delaying effects.

  12. Beauty in the eye of the beholder: Using facial electromyography to examine the association between eating disorder symptoms and perceptions of emaciation among undergraduate women.

    Science.gov (United States)

    Dodd, Dorian R; Velkoff, Elizabeth A; Forrest, Lauren N; Fussner, Lauren M; Smith, April

    2017-06-01

    Thin-ideal internalization, drive for thinness, and over-evaluation of the importance of thinness are associated with eating disorders (EDs). However, little research has examined to what extent perceptions of emaciation are also associated with ED symptoms. In the present study, 80 undergraduate women self-reported on ED symptomatology and perceptions of emaciated, thin, and overweight female bodies. While participants viewed images of these different body types, facial electromyography was used to measure activation of facial muscles associated with disgust reactions. Emaciated and overweight bodies were rated negatively and elicited facial responses consistent with disgust. Further, ED symptomatology was associated with pronounced aversion to overweight bodies (assessed via self-report pleasantness ratings), and attenuated negative affect to emaciated bodies (assessed via facial electromyography). The latter association was significant even when controlling for self-reported perceptions of emaciation, suggesting that psychophysiological methods in ED research may provide valuable information unavailable via self-report. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Polyphosphate nanoparticles on the platelet surface trigger contact system activation

    NARCIS (Netherlands)

    Verhoef, Johan J F; Barendrecht, Arjan D; Nickel, Katrin F; Dijkxhoorn, Kim; Kenne, Ellinor; Labberton, Linda; McCarty, Owen J T; Schiffelers, Raymond; Heijnen, Harry F G; Hendrickx, Antoni P A; Schellekens, Huub; Fens, Marcel H; de Maat, Steven; Renné, Thomas; Maas, Coen

    2017-01-01

    Polyphosphate is an inorganic polymer that can potentiate several interactions in the blood coagulation system. Blood platelets contain polyphosphate, and the secretion of platelet-derived polyphosphate has been associated with increased thrombus formation and activation of coagulation factor XII.

  14. Controlled Release of Biologically Active Silver from Nanosilver Surfaces

    OpenAIRE

    Liu, Jingyu; Sonshine, David A.; Shervani, Saira; Hurt, Robert H.

    2010-01-01

    Major pathways in the antibacterial activity and eukaryotic toxicity of nano-silver involve the silver cation and its soluble complexes, which are well established thiol toxicants. Through these pathways, nano-silver behaves in analogy to a drug delivery system, in which the particle contains a concentrated inventory of an active species, the ion, which is transported to and released near biological target sites. Although the importance of silver ion in the biological response to nano-silver ...

  15. Giant and switchable surface activity of liquid metal via surface oxidation

    OpenAIRE

    Khan, Mohammad Rashed; Eaker, Collin B.; Bowden, Edmond F.; Dickey, Michael D.

    2014-01-01

    We present a method to control the interfacial energy of a liquid metal via electrochemical deposition (or removal) of an oxide layer on its surface. Unlike conventional surfactants, this approach can tune the interfacial tension of a metal significantly (from ∼7× that of water to near zero), rapidly, and reversibly using only modest voltages. These properties can be harnessed to induce previously unidentified electrohydrodynamic phenomena for manipulating liquid metal alloys based on gallium...

  16. MICROBIAL SURFACE-ACTIVE SUBSTANCES AS ANTIADHESIVE AGENTS

    Directory of Open Access Journals (Sweden)

    T. P. Pirog

    2016-06-01

    Full Text Available The literature data of recent years about capacity of biosurfactants synthesized by bacteria (Pseudomonas, Lactobacillus, Bacillus and fungi (Candida, Trichosporon, Saccharomyces not only to avert the adhesion of microorganisms on the different materials, but also to destroy formed biofilms on them were presented. The perspective of biosurfactants to prevent pathogens colonization on biotic and abiotic surfaces, that is known, can be a reason of cause and spread of infectious diseases was discussed. The data of our researches about antiadhesive properties of biosurfactants synthesized by Acinetobacter calcoaceticus IMV B-7241, Nocardia vaccinni IMV B-7405 and Rhodococcus erythropolis IMV Ac-5017 were presented.

  17. Humeral external rotation handling by using the Bobath concept approach affects trunk extensor muscles electromyography in children with cerebral palsy.

    Science.gov (United States)

    Grazziotin Dos Santos, C; Pagnussat, Aline S; Simon, A S; Py, Rodrigo; Pinho, Alexandre Severo do; Wagner, Mário B

    2014-10-20

    This study aimed to investigate the electromyographic activity of cervical and trunk extensors muscles in children with cerebral palsy during two handlings according to the Bobath concept. A crossover trial involving 40 spastic diplegic children was conducted. Electromyography (EMG) was used to measure muscular activity at sitting position (SP), during shoulder internal rotation (IR) and shoulder external rotation (ER) handlings, which were performed using the elbow joint as key point of control. Muscle recordings were performed at the fourth cervical (C4) and at the tenth thoracic (T10) vertebral levels. The Gross Motor Function Classification System (GMFCS) was used to assess whether muscle activity would vary according to different levels of severity. Humeral ER handling induced an increase on EMG signal of trunk extensor muscles at the C4 (P=0.007) and T10 (P<0.001) vertebral levels. No significant effects were observed between SP and humeral IR handling at C4 level; However at T10 region, humeral IR handling induced an increase of EMG signal (P=0.019). Humeral ER resulted in an increase of EMG signal at both levels, suggesting increase of extensor muscle activation. Furthermore, the humeral ER handling caused different responses on EMG signal at T10 vertebra level, according to the GMFCS classification (P=0.017). In summary, an increase of EMG signal was observed during ER handling in both evaluated levels, suggesting an increase of muscle activation. These results indicate that humeral ER handling can be used for diplegic CP children rehabilitation to facilitate cervical and trunk extensor muscles activity in a GMFCS level-dependent manner. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Resonance surface enhanced Raman optical activity of myoglobin as a result of optimized resonance surface enhanced Raman scattering conditions

    DEFF Research Database (Denmark)

    Abdali, Salim; Johannessen, Christian; Nygaard, Jesper

    2007-01-01

    Using Surface enhanced ROA (SEROA), novel results are achieved by combining Raman Optical Activity (ROA) and resonance Surface Enhanced Raman Scattering (SERRS), applied on myoglobin. The novelty of this work is ascribed the first time reporting on chiral results of a study performed on a protein...... has shown that the SERS effect behaves consequently, depending on the concentration ratio of each component, i.e., myoglobin, Ag colloids and NaCl. Accordingly, it is shown here that SERS intensity has its maximum at certain concentration of these components, whereas below or above this value...

  19. Effects of steam activation on the pore structure and surface chemistry of activated carbon derived from bamboo waste

    Science.gov (United States)

    Zhang, Yan-Juan; Xing, Zhen-Jiao; Duan, Zheng-Kang; Li, Meng; Wang, Yin

    2014-10-01

    The effects of steam activation on the pore structure evolution and surface chemistry of activated carbon (AC) obtained from bamboo waste were investigated. Nitrogen adsorption-desorption isotherms revealed that higher steam activation temperatures and/or times promoted the creation of new micropores and widened the existing micropores, consequently decreasing the surface area and total pore volume. Optimum conditions included an activation temperature of 850 °C, activation time of 120 min, and steam flush generated from deionized water of 0.2 cm3 min-1. Under these conditions, AC with a BET surface area of 1210 m2 g-1 and total pore volume of 0.542 cm-3 g-1was obtained. Changes in surface chemistry were determined through Boehm titration, pH measurement, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Results revealed the presence of a large number of basic groups on the surface of the pyrolyzed char and AC. Steam activation did not affect the species of oxygen-containing groups but changed the contents of these species when compared with pyrolyzed char. Scanning electron microscopy was used to observe the surface morphology of the products. AC obtained under optimum conditions showed a monolayer adsorption capacity of 330 mg g-1 for methylene blue (MB), which demonstrates its excellent potential for MB adsorption applications.

  20. Modification of polymer surfaces to enhance enzyme activity and stability

    DEFF Research Database (Denmark)

    Hoffmann, Christian

    Enzyme immobilization is an important concept for the development of improved biocatalytic processes, primarily through facilitated separation procedures. However, enzyme immobilization usually comes at a price of reduced biocatalytic activity. For this reason, different immobilization methods have...... already been developed, combining the same goal to improve enzyme activity, stability and selectivity. Polymer materials have shown, due to their easy processibility and versatile properties, high potential as enzyme support. However, in order to achieve improved enzyme performance, the combination...... of different factors, such as the nature of the enzyme, the properties of the support, the type of immobilization and the interaction between enzyme and support, has to be taken into consideration. In this thesis, these factors are pursued and addressed by exploiting various types of polymers with focus...

  1. Effect of polymer surface activity on cavitation nuclei stability against dissolution

    Science.gov (United States)

    Porter, Tyrone M.; Crum, Lawrence A.; Stayton, Patrick S.; Hoffman, Allan S.

    2004-08-01

    The persistence of acoustic cavitation in a pulsed wave ultrasound regime depends upon the ability of cavitation nuclei, i.e., bubbles, to survive the off time between pulses. Due to the dependence of bubble dissolution on surface tension, surface-active agents may affect the stability of bubbles against dissolution. In this study, measurements of bubble dissolution rates in solutions of the surface-active polymer poly(propyl acrylic acid) (PPAA) were conducted to test this premise. The surface activity of PPAA varies with solution pH and concentration of dissolved polymer molecules. The surface tension of PPAA solutions (55-72 dynes/cm) that associated with the polymer surface activity was measured using the Wilhelmy plate technique. Samples of these polymer solutions then were exposed to 1.1 MHz high intensity focused ultrasound, and the dissolution of bubbles created by inertial cavitation was monitored using an active cavitation detection scheme. Analysis of the pulse echo data demonstrated that bubble dissolution time was inversely proportional to the surface tension of the solution. Finally, comparison of the experimental results with dissolution times computed from the Epstein-Plesset equation suggests that the radii of residual bubbles from inertial cavitation increase as the surface tension decreases.

  2. Cell-surface display of the active mannanase in Yarrowia lipolytica with a novel surface-display system.

    Science.gov (United States)

    Yang, Xiao-Song; Jiang, Zheng-Bing; Song, Hui-Ting; Jiang, Si-Jing; Madzak, Catherine; Ma, Li-Xin

    2009-10-13

    A novel surface-display system was constructed using the cell-wall anchor protein Flo1p from Saccharomyces cerevisiae, the mannanase (man1) from Bacillus subtilis fused with the C-terminus of Flo1p and the 6xHis tag was inserted between Flo1p and man1. The fusion protein was displayed on the cell surface of Yarrowia lipolytica successfully, and it was confirmed by immunofluorescence. In succession, the surface-displayed mannanase was characterized. The optimum catalytic conditions for the recombinant mannanase were 55 degrees C at pH 6.0, and it exhibited high stability against pH variation. The highest activity of the recombinant mannanase reached 62.3 IU/g (dry cell weight) after the recombinant was cultivated for 96 h in YPD medium [1% (w/v) yeast extract/2% (w/v) peptone/2% (w/v) glucose]. To our knowledge, the present paper is the first to report that high-activity mannanase is displayed on the cell surface of Y. lipolytica with Flo1p.

  3. Effects of surface active agents on DNAPL migration and distribution in saturated porous media.

    Science.gov (United States)

    Cheng, Zhou; Gao, Bin; Xu, Hongxia; Sun, Yuanyuan; Shi, Xiaoqing; Wu, Jichun

    2016-11-15

    Dissolved surface active agents such as surfactant and natural organic matter can affect the distribution and fate of dense nonaqueous liquids (DNAPLs) in soil and groundwater systems. This work investigated how two common groundwater surface active agents, humic acid (HA) and Tween 80, affected tetrachloroethylene (PCE) migration and source zone architecture in saturated porous media under environmentally relevant conditions. Batch experiments were first conducted to measure the contact angles and interfacial tensions (IFT) between PCE and quartz surface in water containing different amount of surface active agents. Results showed that the contact angle increased and IFT decreased with concentration of surface active agent increasing, and Tween 80 was much more effective than HA. Five 2-D flow cell experiments were then conducted. Correspondingly, Tween 80 showed strong effects on the migration and distribution of PCE in the porous media due to its ability to change the medium wettability from water-wet into intermediate/NAPL-wet. The downward migration velocities of the PCE in three Tween 80 cells were slower than those in the other two cells. In addition, the final saturation of the PCE in the cells containing surface active agents was higher than that in the water-only cell. Results from this work indicate that the presence of surface active agents in groundwater may strongly affect the fate and distribution of DNAPL through altering porous medium wettability. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Reinforcement of a porous collagen scaffold with surface-activated PLA fibers.

    Science.gov (United States)

    Liu, Xi; Huang, Changbin; Feng, Yujie; Liang, Jie; Fan, Yujiang; Gu, Zhongwei; Zhang, Xingdong

    2010-01-01

    A hybrid porous collagen scaffold mechanically reinforced with surface-activated poly(lactic acid) (PLA) fiber was prepared. PLA fibers, 20 mum in diameter and 1 mm in length, were aminolyzed with hexanediamine to introduce free amino groups on the surfaces. After the amino groups were transferred to aldehyde groups by treatment with glutaraldehyde, different amounts (1.5, 3, 5 and 8 mg) of surface-activated PLA fibers were homogeneously mixed with 2 ml type-I collagen solution (pH 2.8, 0.6 wt%). This mixture solution was then freeze-dried and cross-linked to obtain collagen sponges with surface-activated PLA fiber. Scanning electron microscopy observation indicated that the collagen sponges had a highly interconnected porous structure with an average pore size of 170 mum, irrespective of PLA fiber incorporation. The dispersion of surface-activated PLA fibers was homogeneous in collagen sponge, in contrast to unactivated PLA fibers. The compression modulus test results showed that, compared with unactivated PLA fibers, the surface-activated PLA fibers enhanced the resistance of collagen sponge to compression more significantly. Cytotoxicity assay by MTT test showed no cytotoxicity of these collagen sponges. L929 mouse fibroblast cell-culture studies in vitro revealed that the number of L929 cells attached to the collagen sponge with surface-activated PLA fibers, both 6 h and 24 h after seeding, was higher than that in pure collagen sponge and sponge with unactivated PLA fibers. In addition, a better distribution of cells infiltrated in collagen sponge with surface-activated PLA fibers was observed by histological staining. These results indicated that the collagen sponge reinforced with surface-activated PLA fibers is a promising biocompatible scaffold for tissue engineering.

  5. Functional mapping of the pelvic floor and sphincter muscles from high-density surface EMG recordings.

    Science.gov (United States)

    Peng, Yun; He, Jinbao; Khavari, Rose; Boone, Timothy B; Zhang, Yingchun

    2016-11-01

    Knowledge of the innervation of pelvic floor and sphincter muscles is of great importance to understanding the pathophysiology of female pelvic floor dysfunctions. This report presents our high-density intravaginal and intrarectal electromyography (EMG) probes and a comprehensive innervation zone (IZ) imaging technique based on high-density EMG readings to characterize the IZ distribution. Both intravaginal and intrarectal probes are covered with a high-density surface electromyography electrode grid (8 × 8). Surface EMG signals were acquired in ten healthy women performing maximum voluntary contractions of their pelvic floor. EMG decomposition was performed to separate motor-unit action potentials (MUAPs) and then localize their IZs. High-density surface EMG signals were successfully acquired over the vaginal and rectal surfaces. The propagation patterns of muscle activity were clearly visualized for multiple muscle groups of the pelvic floor and anal sphincter. During each contraction, up to 218 and 456 repetitions of motor units were detected by the vaginal and rectal probes, respectively. MUAPs were separated with their IZs identified at various orientations and depths. The proposed probes are capable of providing a comprehensive mapping of IZs of the pelvic floor and sphincter muscles. They can be employed as diagnostic and preventative tools in clinical practices.

  6. The feasibility of hypnotic analgesia in ameliorating pain and anxiety among adults undergoing needle electromyography.

    Science.gov (United States)

    Slack, David; Nelson, Lonnie; Patterson, David; Burns, Stephen; Hakimi, Kevin; Robinson, Lawrence

    2009-01-01

    Our hypothesis was that hypnotic analgesia reduces pain and anxiety during electromyography (EMG). We performed a prospective randomized, controlled clinical trial at outpatient electrodiagnostic clinics in teaching hospitals. Just before EMG, 26 subjects were randomized to one of three 20-min audio programs: education about EMG (EDU) (n = 8); hypnotic induction without analgesic suggestion (n = 10); or hypnotic induction with analgesic suggestion (n = 8). The blinded electromyographer provided a posthypnotic suggestion at the start of EMG. After EMG, subjects rated worst and average pain and anxiety using visual analog scales. Mean values for the EDU, hypnotic induction without analgesic suggestion, and hypnotic induction with analgesic suggestion groups were not significantly different (mean +/- SD): worst pain 67 +/- 25, 42 +/- 18, and 49 +/- 30; average pain 35 +/- 26, 27 +/- 14, and 25 +/- 22; and anxiety 44 +/- 41, 42 +/- 23, and 22 +/- 24. When hypnosis groups were merged (n = 18) and compared with the EDU condition (n = 8), average and worst pain and anxiety were less for the hypnosis group than EDU, but this was statistically significant only for worst pain (hypnosis, 46 +/- 24 vs. EDU, 67 +/- 35; P = 0.049) with a 31% average reduction. A short hypnotic induction seems to reduce worst pain during electromyography.

  7. Simultaneous Recording and Analysis of Uterine and Abdominal Muscle Electromyographic Activity in Nulliparous Women During Labor.

    Science.gov (United States)

    Qian, Xueya; Li, Pin; Shi, Shao-Qing; Garfield, Robert E; Liu, Huishu

    2017-03-01

    To record and characterize electromyography (EMG) from the uterus and abdominal muscles during the nonlabor to first and second stages of labor and to define relationships to contractions. Nulliparous patients without any treatments were used (n = 12 nonlabor stage, 48 during first stage and 33 during second stage). Electromyography of both uterine and abdominal muscles was simultaneously recorded from electrodes placed on patients' abdominal surface using filters to separate uterine and abdominal EMG. Contractions of muscles were also recorded using tocodynamometry. Electromyography was characterized by analysis of various parameters. During the first stage of labor, when abdominal EMG is absent, uterine EMG bursts temporally correspond to contractions. In the second stage, uterine EMG bursts usually occur at same frequency as groups of abdominal bursts and precede abdominal bursts, whereas abdominal EMG bursts correspond to contractions and are accompanied by feelings of "urge to push." Uterine EMG increases progressively from nonlabor to second stage of labor. (1) Uterine EMG activity can be separated from abdominal EMG events by filtering. (2) Uterine EMG gradually evolves from the antepartum stage to the first and second stages of labor. (3) Uterine and abdominal EMG reflect electrical activity of the muscles during labor and are valuable to assess uterine and abdominal muscle events that control labor. (4) During the first stage of labor uterine, EMG is responsible for contractions, and during the second stage, both uterine and abdominal muscle participate in labor.

  8. Molecular Characteristics and Biological Functions of Surface-Active and Surfactant Proteins.

    Science.gov (United States)

    Sunde, Margaret; Pham, Chi L L; Kwan, Ann H

    2017-06-20

    Many critical biological processes take place at hydrophobic:hydrophilic interfaces, and a wide range of organisms produce surface-active proteins and peptides that reduce surface and interfacial tension and mediate growth and development at these boundaries. Microorganisms produce both small lipid-associated peptides and amphipathic proteins that allow growth across water:air boundaries, attachment to surfaces, predation, and improved bioavailability of hydrophobic substrates. Higher-order organisms produce surface-active proteins with a wide variety of functions, including the provision of protective foam environments for vulnerable reproductive stages, evaporative cooling, and gas exchange across airway membranes. In general, the biological functions supported by these diverse polypeptides require them to have an amphipathic nature, and this is achieved by a diverse range of molecular structures, with some proteins undergoing significant conformational change or intermolecular association to generate the structures that are surface active.

  9. The Assessment Methods of Laryngeal Muscle Activity in Muscle Tension Dysphonia: A Review

    Science.gov (United States)

    Khoddami, Seyyedeh Maryam; Nakhostin Ansari, Noureddin; Izadi, Farzad; Talebian Moghadam, Saeed

    2013-01-01

    The purpose of this paper is to review the methods used for the assessment of muscular tension dysphonia (MTD). The MTD is a functional voice disorder associated with abnormal laryngeal muscle activity. Various assessment methods are available in the literature to evaluate the laryngeal hyperfunction. The case history, laryngoscopy, and palpation are clinical methods for the assessment of patients with MTD. Radiography and surface electromyography (EMG) are objective methods to provide physiological information about MTD. Recent studies show that surface EMG can be an effective tool for assessing muscular tension in MTD. PMID:24319372

  10. Nisin-activated hydrophobic and hydrophilic surfaces: assessment of peptide adsorption and antibacterial activity against some food pathogens.

    Science.gov (United States)

    Karam, Layal; Jama, Charafeddine; Mamede, Anne-Sophie; Boukla, Samir; Dhulster, Pascal; Chihib, Nour-Eddine

    2013-12-01

    An effective antimicrobial packaging or food contact surface should be able to kill or inhibit micro-organisms that cause food-borne illnesses. Setting up such systems, by nisin adsorption on hydrophilic and hydrophobic surfaces, is still a matter of debate. For this purpose, nisin was adsorbed on two types of low-density polyethylene: the hydrophobic native film and the hydrophilic acrylic acid-treated surface. The antibacterial activity was compared for those two films and it was highly dependent on the nature of the surface and the nisin-adsorbed amount. The hydrophilic surfaces presented higher antibacterial activity and higher amount of nisin than the hydrophobic surfaces. The effectiveness of the activated surfaces was assessed against Listeria innocua and the food pathogens Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus. S. aureus was more sensitive than the three other test bacteria toward both nisin-functionalized films. Simulation tests to mimic refrigerated temperature showed that the films were effective at 20 and 4 °C with no significant difference between the two temperatures after 30 min of exposure to culture media.

  11. Competitive Adsorption between Nanoparticles and Surface Active Ions for the Oil-Water Interface.

    Science.gov (United States)

    Hua, Xiaoqing; Bevan, Michael A; Frechette, Joelle

    2018-04-16

    Nanoparticles (NPs) can add functionality (e.g., catalytic, optical, rheological) to an oil-water interface. Adsorption of ∼10 nm NPs can be reversible; however, the mechanisms for adsorption and its effects on surface pressure remain poorly understood. Here we demonstrate how the competitive reversible adsorption of NPs and surfactants at fluid interfaces can lead to independent control of both the adsorbed amount and surface pressure. In contrast to prior work, both species investigated (NPs and surfactants) interact reversibly with the interface and without the surface active species binding to NPs. Independent measurements of the adsorption and surface pressure isotherms allow determination of the equation of state (EOS) of the interface under conditions where the NPs and surfactants are both in dynamic equilibrium with the bulk phase. The adsorption and surface pressure measurements are performed with gold NPs of two different sizes (5 and 10 nm), at two pH values, and across a wide concentration range of surfactant (tetrapentylammonium, TPeA + ) and NPs. We show that free surface active ions compete with NPs for the interface and give rise to larger surface pressures upon the adsorption of NPs. Through a competitive adsorption model, we decouple the contributions of NPs wetting at the interface and their surface activity on the measured surface pressure. We also demonstrate reversible control of adsorbed amount via changes in the surfactant concentration or the aqueous phase pH.

  12. Cell-surface expression of Hsp70 on hematopoietic cancer cells after inhibition of HDAC activity

    DEFF Research Database (Denmark)

    Jensen, Helle; Andresen, Lars; Hansen, Karen Aagaard

    clinically applied reagents, such as alkyl-lysophospholipides, chemotherapeutic agents, and anti-inflammatory reagents, have been found to enhance Hsp70 surface expression on cancer cells. We have found that inhibition of histone deacetylase (HDAC) activity leads to surface expression of Hsp70 on various...

  13. Novel Chiroptical Analysis of Hemoglobin by Surface Enhanced Resonance Raman Optical Activity Spectroscopy

    DEFF Research Database (Denmark)

    Brazhe, Nadezda; Brazhe, Alexey; Sosnovtseva, Olga

    2010-01-01

    The metalloprotein hemoglobin (Hb) was studied using surface enhanced resonance Raman spectroscopy (SERRS) and surface enhanced resonance Raman optical activity (SERROA). The SERROA results are analyzed and compared with the SERRS, and the later to the resonance Raman (RRS) performed on Hb...

  14. Identifying the Active Surfaces of Electrochemically Tuned LiCoO2 for Oxygen Evolution Reaction

    International Nuclear Information System (INIS)

    Lu, Zhiyi; Chen, Guangxu; Li, Yanbin; Wang, Haotian; Xie, Jin

    2017-01-01

    Identification of active sites for catalytic processes has both fundamental and technological implications for rational design of future catalysts. Herein, we study the active surfaces of layered lithium cobalt oxide (LCO) for the oxygen evolution reaction (OER) using the enhancement effect of electrochemical delithiation (De-LCO). Our theoretical results indicate that the most stable (0001) surface has a very large overpotential for OER independent of lithium content. In contrast, edge sites such as the nonpolar (1120) and polar (0112) surfaces are predicted to be highly active and dependent on (de)lithiation. The effect of lithium extraction from LCO on the surfaces and their OER activities can be understood by the increase of Co 4+ sites relative to Co 3+ and by the shift of active oxygen 2p states. Experimentally, it is demonstrated that LCO nanosheets, which dominantly expose the (0001) surface show negligible OER enhancement upon delithiation. However, a noticeable increase in OER activity (~0.1 V in overpotential shift at 10 mA cm –2 ) is observed for the LCO nanoparticles, where the basal plane is greatly diminished to expose the edge sites, consistent with the theoretical simulations. In addition, we find that the OER activity of De-LCO nanosheets can be improved if we adopt an acid etching method on LCO to create more active edge sites, which in turn provides a strong evidence for the theoretical indication.

  15. Characterization of fucosyltransferase activity during mouse spermatogenesis: Evidence for a cell surface fucosyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Cardullo, R.A.; Armant, D.R.; Millette, C.F. (Harvard Medical School, Boston, MA (USA))

    1989-02-21

    Fucosyltransferase activity was quantified in mouse germ cells at different stages of spermatogenesis. Specifically, fucosyltransferase activities of pachytene spermatocytes, round spermatids, and cauda epididymal sperm were compared. Fucosyltranferase activity of mixed germ cells displayed an apparent V{sub max} of 17 pmol (mg of protein){sup {minus}1} min{sup {minus}1} and an apparent K{sub m} of approximately 13 {mu}M for GDP-L-({sup 14}C)fucose in the presence of saturating amounts of asialofetuin at 33{degree}C. Under these conditions, cellular fucosyltransferase activity was found to increase during spermatogenesis. In agreement with assays of intact cells, examination of subcellular fractions indicated that a large fraction of fucosyltransferase activity was associated with the cell surface. The fraction of fucosyltransferase activity that was associated with the cell surface progressively increased throughout spermatogenesis and epididymal maturation so that nearly all of the fucosyltransferase in epididymal sperm was on the cell surface. Specifically, by comparison of activities in the presence and absence of the detergent NP-40, the fraction of fucosyltransferase activity that was associated with the cell surface in pachytene spermatocytes, round spermatids, and epididymal sperm was 0.36, 0.5, and 0.85, respectively. These results suggest that a cell surface fucosyltransferase may be important during differentiation of spermatogenic cells in the testis as well as during epididymal maturation and fertilization.

  16. Deep Learning with Convolutional Neural Networks Applied to Electromyography Data: A Resource for the Classification of Movements for Prosthetic Hands.

    Science.gov (United States)

    Atzori, Manfredo; Cognolato, Matteo; Müller, Henning

    2016-01-01

    Natural control methods based on surface electromyography (sEMG) and pattern recognition are promising for hand prosthetics. However, the control robustness offered by scientific research is still not sufficient for many real life applications, and commercial prostheses are capable of offering natural control for only a few movements. In recent years deep learning revolutionized several fields of machine learning, including computer vision and speech recognition. Our objective is to test its methods for natural control of robotic hands via sEMG using a large number of intact subjects and amputees. We tested convolutional networks for the classification of an average of 50 hand movements in 67 intact subjects and 11 transradial amputees. The simple architecture of the neural network allowed to make several tests in order to evaluate the effect of pre-processing, layer architecture, data augmentation and optimization. The classification results are compared with a set of classical classification methods applied on the same datasets. The classification accuracy obtained with convolutional neural networks using the proposed architecture is higher than the average results obtained with the classical classification methods, but lower than the results obtained with the best reference methods in our tests. The results show that convolutional neural networks with a very simple architecture can produce accurate results comparable to the average classical classification methods. They show that several factors (including pre-processing, the architecture of the net and the optimization parameters) can be fundamental for the analysis of sEMG data. Larger networks can achieve higher accuracy on computer vision and object recognition tasks. This fact suggests that it may be interesting to evaluate if larger networks can increase sEMG classification accuracy too.

  17. Nonlinear smooth orthogonal decomposition of kinematic features of sawing reconstructs muscle fatigue evolution as indicated by electromyography.

    Science.gov (United States)

    Segala, David B; Gates, Deanna H; Dingwell, Jonathan B; Chelidze, David

    2011-03-01

    Tracking or predicting physiological fatigue is important for developing more robust training protocols and better energy supplements and/or reducing muscle injuries. Current methodologies are usually impractical and/or invasive and may not be realizable outside of laboratory settings. It was recently demonstrated that smooth orthogonal decomposition (SOD) of phase space warping (PSW) features of motion kinematics can identify fatigue in individual muscle groups. We hypothesize that a nonlinear extension of SOD will identify more optimal fatigue coordinates and provide a lower-dimensional reconstruction of local fatigue dynamics than the linear SOD. Both linear and nonlinear SODs were applied to PSW features estimated from measured kinematics to reconstruct muscle fatigue dynamics in subjects performing a sawing motion. Ten healthy young right-handed subjects pushed a weighted handle back and forth until voluntary exhaustion. Three sets of joint kinematic angles were measured from the right upper extremity in addition to surface electromyography (EMG) recordings. The SOD coordinates of kinematic PSW features were compared against independently measured fatigue markers (i.e., mean and median EMG spectrum frequencies of individual muscle groups). This comparison was based on a least-squares linear fit of a fixed number of the dominant SOD coordinates to the appropriate local fatigue markers. Between subject variability showed that at most four to five nonlinear SOD coordinates were needed to reconstruct fatigue in local muscle groups, while on average 15 coordinates were needed for the linear SOD. Thus, the nonlinear coordinates provided a one-order-of-magnitude improvement over the linear ones.

  18. The Gluteus Medius Vs. Thigh Muscles Strength Ratio and Their Relation to Electromyography Amplitude During a Farmer’s Walk Exercise

    Directory of Open Access Journals (Sweden)

    Stastny Petr

    2015-03-01

    Full Text Available The strength ratio between hamstrings and quadriceps (H/Q is associated with knee injuries as well as hip abductor muscle (HAB weakness. Sixteen resistance trained men (age, 32.5 ± 4.2 years performed 5 s maximal isometric contractions at 75° of knee flexion/extension and 15° of hip abduction on a dynamometer. After this isometric test they performed a Farmer´s walk exercise to find out if the muscle strength ratio predicted the electromyography amplitude expressed as a percentage of maximum voluntary isometric contraction (%MVIC. The carried load represented a moderate intensity of 75% of the exercise six repetitions maximum (6RM. Electromyography data from the vastus medialis (VM, vastus lateralis (VL, biceps femoris (BF and gluteus medius (Gmed on each leg were collected during the procedure. The groups selected were participants with H/Q ≥ 0.5, HQ < 0.5, HAB/H ≥ 1, HAB/H < 1, HAB/Q ≥ 0.5 and HAB/Q < 0.5. One way ANOVA showed that Gmed activity was significantly greater in the group with HAB/H < 1 (42 ± 14 %MVIC as compared to HAB/H ≥ 1 (26 ± 10 %MVIC and HAB/Q < 0.5 (47 ± 19 %MVIC compared to HAB/Q ≥ 0.5 (26 ± 12 %MVIC. The individuals with HAB/H < 1 were found to have greater activation of their Gmed during the Farmer’s walk exercise. Individuals with HAB/Q < 0.5 had greater activation of the Gmed. Gmed strength ratios predict the muscle involvement when a moderate amount of the external load is used. The Farmer’s walk is recommended as an exercise which can strengthen the gluteus medius, especially for individuals with a HAB/H ratio < 1 and HAB/Q < 0.5.

  19. Surface modification of Cobalt ferrite nano-hollowspheres for inherent multiple photoluminescence and enhanced photocatalytic activities

    Science.gov (United States)

    Talukdar, Souvanik; Mandal, Dipika; Mandal, Kalyan

    2017-03-01

    Nano-hollow spheres (NHSs) are the new drift in magnetic nanostructures as they provide more surface area at nano length scale with enhanced magnetic properties compared to their nanoparticle counterpart. Here we reported the synthesis of biocompatible CoFe2O4 NHSs of diameter around 250 nm and emergence of intrinsic multiple photoluminescence from blue, green to red on modifying their surface with small organic ligands like tartrate. The surface modified NHSs also showed notable photocatalytic activity towards the degradation of environmentally malefic dyes like Methylene Blue and Rhodamine B. The surface modified NHSs are found to exhibit superior magnetic properties.

  20. Establishment of Epithelial Attachment on Titanium Surface Coated with Platelet Activating Peptide.

    Directory of Open Access Journals (Sweden)

    Shiho Sugawara

    Full Text Available The aim of this study was to produce epithelial attachment on a typical implant abutment surface of smooth titanium. A challenging complication that hinders the success of dental implants is peri-implantitis. A common cause of peri-implantitis may results from the lack of epithelial sealing at the peri-implant collar. Histologically, epithelial sealing is recognized as the attachment of the basement membrane (BM. BM-attachment is promoted by activated platelet aggregates at surgical wound sites. On the other hand, platelets did not aggregate on smooth titanium, the surface typical of the implant abutment. We then hypothesized that epithelial BM-attachment was produced when titanium surface was modified to allow platelet aggregation. Titanium surfaces were coated with a protease activated receptor 4-activating peptide (PAR4-AP. PAR4-AP coating yielded rapid aggregation of platelets on the titanium surface. Platelet aggregates released robust amount of epithelial chemoattractants (IGF-I, TGF-β and growth factors (EGF, VEGF on the titanium surface. Human gingival epithelial cells, when they were co-cultured on the platelet aggregates, successfully attached to the PAR4-AP coated titanium surface with spread laminin5 positive BM and consecutive staining of the epithelial tight junction component ZO1, indicating the formation of complete epithelial sheet. These in-vitro results indicate the establishment of epithelial BM-attachment to the titanium surface.

  1. Laboratory measurement of the interface pressures applied by active therapy support surfaces: a consensus document.

    Science.gov (United States)

    2010-02-01

    A key element in pressure ulcer prevention and management is the selection of appropriate pressure redistributing (PR) patient support surfaces for use while seated and in bed. However little explicit guidance exists allowing standardised quantitative comparison of different PR surfaces based upon their ability to redistribute pressure from anatomical landmarks such as the heels and sacrum. In 2008 a working group was established in Europe through the US National Pressure Ulcer Advisory Panel (NPUAP) support surface standardisation initiative (S3I) and under the aegis of the European Pressure Ulcer Advisory Panel with the specific remit of developing test methods for the evaluation of active therapy support surfaces (alternating pressure air mattresses). This report describes a consensus development process to agree test methods appropriate to compare active therapy surfaces based upon their ability to redistribute pressure from the sacrum and the heels. Copyright 2009 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

  2. Micro Surface Defect Detection Method for Silicon Steel Strip Based on Saliency Convex Active Contour Model

    Directory of Open Access Journals (Sweden)

    Kechen Song

    2013-01-01

    Full Text Available Accurate detection of surface defect is an indispensable section in steel surface inspection system. In order to detect the micro surface defect of silicon steel strip, a new detection method based on saliency convex active contour model is proposed. In the proposed method, visual saliency extraction is employed to suppress the clutter background for the purpose of highlighting the potential objects. The extracted saliency map is then exploited as a feature, which is fused into a convex energy minimization function of local-based active contour. Meanwhile, a numerical minimization algorithm is introduced to separate the micro surface defects from cluttered background. Experimental results demonstrate that the proposed method presents good performance for detecting micro surface defects including spot-defect and steel-pit-defect. Even in the cluttered background, the proposed method detects almost all of the microdefects without any false objects.

  3. Protein immobilization on epoxy-activated thin polymer films: effect of surface wettability and enzyme loading.

    Science.gov (United States)

    Chen, Bo; Pernodet, Nadine; Rafailovich, Miriam H; Bakhtina, Asya; Gross, Richard A

    2008-12-02

    A series of epoxy-activated polymer films composed of poly(glycidyl methacrylate/butyl methacrylate/hydroxyethyl methacrylate) were prepared. Variation in comonomer composition allowed exploration of relationships between surface wettability and Candida antartica lipase B (CALB) binding to surfaces. By changing solvents and polymer concentrations, suitable conditions were developed for preparation by spin-coating of uniform thin films. Film roughness determined by AFM after incubation in PBS buffer for 2 days was less than 1 nm. The occurrence of single CALB molecules and CALB aggregates at surfaces was determined by AFM imaging and measurements of volume. Absolute numbers of protein monomers and multimers at surfaces were used to determine values of CALB specific activity. Increased film wettability, as the water contact angle of films increased from 420 to 550, resulted in a decreased total number of immobilized CALB molecules. With further increases in the water contact angle of films from 55 degrees to 63 degrees, there was an increased tendency of CALB molecules to form aggregates on surfaces. On all flat surfaces, two height populations, differing by more than 30%, were observed from height distribution curves. They are attributed to changes in protein conformation and/or orientation caused by protein-surface and protein-protein interactions. The fraction of molecules in these populations changed as a function of film water contact angle. The enzyme activity of immobilized films was determined by measuring CALB-catalyzed hydrolysis of p-nitrophenyl butyrate. Total enzyme specific activity decreased by decreasing film hydrophobicity.

  4. Ozonation of benzothiazole saturated-activated carbons: Influence of carbon chemical surface properties

    International Nuclear Information System (INIS)

    Valdes, H.; Zaror, C.A.

    2006-01-01

    The combined or sequential use of ozone and activated carbon to treat toxic effluents has increased in recent years. However, little is known about the influence of carbon surface active sites on ozonation of organic adsorbed pollutants. This paper presents experimental results on the effect of metal oxides and oxygenated surface groups on gaseous ozonation of spent activated carbons. Benzothiazole (BT) was selected as a target organic compound in this study due to its environmental concern. Activated carbons with different chemical surface composition were prepared from a Filtrasorb-400 activated carbon. Pre-treatment included: ozonation, demineralisation, and deoxygenation of activated carbon. Ozonation experiments of BT saturated-activated carbons were conducted in a fixed bed reactor loaded with 2 g of carbon samples. The reactor was fed with an O 2 /O 3 gas mixture (2 dm 3 /min, 5 g O 3 /h), for a given exposure time, in the range 10-120 min, at 298 K and 1 atm. Results show that extended gaseous ozonation of activated carbon saturated with BT led to the effective destruction of the adsorbate by oxidation reactions. Oxidation of BT adsorbed on activated carbon seemed to occur via both direct reaction with ozone molecules, and by oxygen radical species generated by catalytic ozone decomposition on metallic surface sites

  5. Control surfaces of aquatic vertebrates: active and passive design and function.

    Science.gov (United States)

    Fish, Frank E; Lauder, George V

    2017-12-01

    Aquatic vertebrates display a variety of control surfaces that are used for propulsion, stabilization, trim and maneuvering. Control surfaces include paired and median fins in fishes, and flippers and flukes in secondarily aquatic tetrapods. These structures initially evolved from embryonic fin folds in fishes and have been modified into complex control surfaces in derived aquatic tetrapods. Control surfaces function both actively and passively to produce torque about the center of mass by the generation of either lift or drag, or both, and thus produce vector forces to effect rectilinear locomotion, trim control and maneuvers. In addition to fins and flippers, there are other structures that act as control surfaces and enhance functionality. The entire body can act as a control surface and generate lift for stability in destabilizing flow regimes. Furthermore, control surfaces can undergo active shape change to enhance their performance, and a number of features act as secondary control structures: leading edge tubercles, wing-like canards, multiple fins in series, finlets, keels and trailing edge structures. These modifications to control surface design can alter flow to increase lift, reduce drag and enhance thrust in the case of propulsive fin-based systems in fishes and marine mammals, and are particularly interesting subjects for future research and application to engineered systems. Here, we review how modifications to control surfaces can alter flow and increase hydrodynamic performance. © 2017. Published by The Company of Biologists Ltd.

  6. Rehabilitation exercise progression for the gluteus medius muscle with consideration for iliopsoas tendinitis: an in vivo electromyography study.

    Science.gov (United States)

    Philippon, Marc J; Decker, Michael J; Giphart, J Erik; Torry, Michael R; Wahoff, Michael S; LaPrade, Robert F

    2011-08-01

    It is common for hip arthroscopy patients to demonstrate significant gluteus medius muscle weakness and concurrent iliopsoas tendinitis. Restoration of gluteus medius muscle function is essential for normal hip function. A progression of hip rehabilitation exercises to strengthen the gluteus medius muscle could be identified that minimize concurrent iliopsoas muscle activation to reduce the risk of developing or aggravating hip flexor tendinitis Descriptive laboratory study. Electromyography (EMG) signals of the gluteus medius and iliopsoas muscles were recorded from 10 healthy participants during 13 hip rehabilitation exercises. The indwelling fine-wire EMG electrodes were inserted under ultrasound guidance. The average and peak EMG amplitudes, normalized by the peak EMG amplitude elicited during maximum voluntary contractions, were determined and rank-ordered from low to high. The ratio of iliopsoas to gluteus medius muscle activity was calculated for each exercise. Exercises were placed into respective time phases based on average gluteus medius EMG amplitude, except that exercises involving hip rotation were avoided in phase I (phase I, initial 4 or 8 weeks; phase II, subsequent 4 weeks; phase III, final 4 weeks). A continuum of hip rehabilitation exercises was identified. Resisted terminal knee extension, resisted knee flexion, and double-leg bridges were identified as appropriate for phase I and resisted hip extension, stool hip rotations, and side-lying hip abduction with wall-sliding for phase II. Hip clam exercises with neutral hips may be used with caution in patients with hip flexor tendinitis. Prone heel squeezes, side-lying hip abduction with internal hip rotation, and single-leg bridges were identified for phase III. This study identified the most appropriate hip rehabilitation exercises for each phase to strengthen the gluteus medius muscle after hip arthroscopy and those to avoid when iliopsoas pain or tendinitis is a concern.

  7. Surface reaction and transport in mixed conductors with electrochemically-active surfaces: a 2-D numerical study of ceria.

    Science.gov (United States)

    Ciucci, Francesco; Chueh, William C; Goodwin, David G; Haile, Sossina M

    2011-02-14

    A two-dimensional, small-bias model has been developed for describing transport through a mixed ionic and electronic conductor (MIEC) with electrochemically-active surfaces, a system of particular relevance to solid oxide fuel cells. Utilizing the h-adaptive finite-element method, we solve the electrochemical potential and flux for both ionic and electronic species in the MIEC, taking the transport properties of Sm(0.15)Ce(0.85)O(1.925-δ) (SDC15). In addition to the ionic flux that flows between the two sides of the cell, there are two types of electronic fluxes: (1) cross-plane current that flows in the same general direction as the ionic current, and (2) in-plane current that flows between the catalytically-active MIEC surface and the metal current collectors. From an evaluation of these fluxes, the macroscopic interfacial resistance is decomposed into an electrochemical reaction resistance and an electron diffusion-drift resistance, the latter associated with the in-plane electronic current. Analysis of the experimental data for the interfacial resistance for hydrogen electro-oxidation on SDC15 having either Pt or Au current collectors (W. Lai and S. M. Haile, J. Am. Ceram. Soc., 2005, 88, 2979-2997; W. C. Chueh, W. Lai and S. M. Haile, Solid State Ionics, 2008, 179, 1036-1041) indicates that surface reaction rather than electron migration is the overall rate-limiting step, and suggests furthermore that the surface reaction rate, which has not been directly measured in the literature, scales with pO2(-1/4). The penetration depth for the in-plane electronic current is estimated at 0.6 μm for the experimental conditions of interest to SDC15, and is found to attain a value as high as 4 μm within the broader range of computational conditions.

  8. Overview of total beta activity index and beta rest in surface waters of the Spanish rivers

    International Nuclear Information System (INIS)

    Pujol, L.; Payeras, J.; Pablo, M. A. de

    2013-01-01

    This work aims to give an overview of the index of total beta activity and the activity index beta rest in surface waters of the main Spanish rivers. These indices are a parameter over water quality that CEDEX comes determined by order of the Ministry of Agriculture, Food and Environment, in water policy. (Author)

  9. Surface-active biopolymers from marine bacteria for potential biotechnological applications

    Directory of Open Access Journals (Sweden)

    Karina Sałek

    2016-03-01

    Full Text Available Surface-active agents are amphiphilic chemicals that are used in almost every sector of modern industry, the bulk of which are produced by organo-chemical synthesis. Those produced from biological sources (biosurfactants and bioemulsifiers, however, have gained increasing interest in recent years due to their wide structural and functional diversity, lower toxicities and high biodegradability, compared to their chemically-synthesised counterparts. This review aims to present a general overview on surface-active agents, including their classification, where new types of these biomolecules may lay awaiting discovery, and some of the main bottlenecks for their industrial-scale production. In particular, the marine environment is highlighted as a largely untapped source for discovering new types of surface-active agents. Marine bacteria, especially those living associated with micro-algae (eukaryotic phytoplankton, are a highly promising source of polymeric surface-active agents with potential biotechnological applications. The high uronic acids content of these macromolecules has been linked to conferring them with amphiphilic qualities, and their high structural diversity and polyanionic nature endows them with the potential to exhibit a wide range of functional diversity. Production yields (e.g. by fermentation for most microbial surface-active agents have often been too low to meet the volume demands of industry, and this principally remains as the most important bottleneck for their further commercial development. However, new developments in recombinant and synthetic biology approaches can offer significant promise to alleviate this bottleneck. This review highlights a particular biotope in the marine environment that offers promise for discovering novel surface-active biomolecules, and gives a general overview on specific areas that researchers and the industry could focus work towards increasing the production yields of microbial surface-active

  10. Effects of jump and balance training on knee kinematics and electromyography of female basketball athletes during a single limb drop landing: pre-post intervention study.

    Science.gov (United States)

    Nagano, Yasuharu; Ida, Hirofumi; Akai, Masami; Fukubayashi, Toru

    2011-07-14

    Some research studies have investigated the effects of anterior cruciate ligament (ACL) injury prevention programs on knee kinematics during landing tasks; however the results were different among the studies. Even though tibial rotation is usually observed at the time of ACL injury, the effects of training programs for knee kinematics in the horizontal plane have not yet been analyzed. The purpose of this study was to determine the effects of a jump and balance training program on knee kinematics including tibial rotation as well as on electromyography of the quadriceps and hamstrings in female athletes. Eight female basketball athletes participated in the experiment. All subjects performed a single limb landing at three different times: the initial test, five weeks later, and one week after completing training. The jump and balance training program lasted for five weeks. Knee kinematics and simultaneous electromyography of the rectus femoris and Hamstrings before training were compared with those measured after completing the training program. After training, regarding the position of the knee at foot contact, the knee flexion angle for the Post-training trial (mean (SE): 24.4 (2.1) deg) was significantly larger than that for the Pre-training trial (19.3 (2.5) deg) (p training trial (40.2 (1.9) deg) was significantly larger than that for the Pre-training trial (34.3 (2.5) deg) (p training. A significant increase was also found in the activity of the hamstrings 50 ms before foot contact (p jump and balance training program successfully increased knee flexion and hamstring activity of female athletes during landing, and has the possibility of producing partial effects to avoid the characteristic knee position observed in ACL injury, thereby preventing injury. However, the expected changes in frontal and transverse kinematics of the knee were not observed.

  11. Preparation of High Surface Area Activated Carbon from Spent Phenolic Resin by Microwave Heating and KOH Activation

    Science.gov (United States)

    Cheng, Song; Zhang, Libo; Zhang, Shengzhou; Xia, Hongying; Peng, Jinhui

    2018-01-01

    The spent phenolic resin is as raw material for preparing high surface area activated carbon (HSAAC) by microwave-assisted KOH activation. The effects of microwave power, activation duration and impregnation ratio (IR) on the iodine adsorption capability and yield of HSAAC were investigated. The surface characteristics of HSAAC were characterized by nitrogen adsorption isotherms, FTIR, SEM and TEM. The operating variables were optimized utilizing the response surface methodology (RSM) and were identified to be microwave power of 700 W, activation duration of 15 min and IR of 4, corresponding to a yield of 51.25 % and an iodine number of 2,384 mg/g. The pore structure parameters of the HSAAC, i. e., Brunauer-Emmett-Teller (BET) surface area, total pore volume, and average pore diameter were estimated to be 4,269 m2/g, 2.396 ml/g and 2.25 nm, respectively, under optimum conditions. The findings strongly support the feasibility of microwave-assisted KOH activation for preparation of HSAAC from spent phenolic resin.

  12. Development of a tree classifier for discrimination of surface mine activity from Landsat digital data

    Science.gov (United States)

    Solomon, J. L.; Miller, W. F.; Quattrochi, D. A.

    1979-01-01

    In a cooperative project with the Geological Survey of Alabama, the Mississippi State Remote Sensing Applications Program has developed a single purpose, decision-tree classifier using band-ratioing techniques to discriminate various stages of surface mining activity. The tree classifier has four levels and employs only two channels in classification at each level. An accurate computation of the amount of disturbed land resulting from the mining activity can be made as a product of the classification output. The utilization of Landsat data provides a cost-efficient, rapid, and accurate means of monitoring surface mining activities.

  13. Utilization and yield of nerve conduction studies and electromyography in older adults

    LENUS (Irish Health Repository)

    Mello, S

    2016-02-01

    Older adults are at increased risk of both central and peripheral neurological disorders. Impaired nerve and muscle deficits contribute to morbidity and reduced quality of life. Our aim was to define the utilization and yield of nerve conduction studies (NCS) and electromyography (EMG) in older adults. We reviewed NCS and EMG records for all patients older than age 65 in the year 2012. Of 1,530 NCS and EMGs performed, 352 (23%) were in patients older than 65 (mean age 73.7, 52% male). Two hundred and eighty-eight (83.7%) of NCS were abnormal as were 102 (71.8%) of EMGs. The likelihood of having an abnormal test result increased with increasing age. The most common diagnosis was peripheral neuropathy 231 (65.4%). The incidence of peripheral neuropathy is particularly high in this age group, and detection is vital to prevent morbidity and improve quality of life.

  14. Listening to music during electromyography does not influence the examinee's anxiety and pain levels.

    Science.gov (United States)

    Abraham, Alon; Drory, Vivian E

    2014-09-01

    Listening to music is a low-cost intervention that has demonstrated ability to reduce pain and anxiety levels in various medical procedures. Subjects undergoing electrophysiological examinations were randomized into a music-listening group and a control group. Visual analog scales were used to measure anxiety and pain levels during the procedure. Thirty subjects were randomized to each group. No statistically significant difference was found in anxiety or pain levels during the procedure between groups. However, most subjects in the music-listening group reported anxiety and pain reduction and would prefer to hear music in a future examination. Although listening to music during electrophysiological examinations did not reduce anxiety or pain significantly, most subjects felt a positive effect and would prefer to hear music; therefore, we suggest that music may be offered optionally in the electromyography laboratory setting. © 2014 Wiley Periodicals, Inc.

  15. Enhanced oxygen reduction activity on surface-decorated perovskite thin films for solid oxide fuel cells

    KAUST Repository

    Mutoro, Eva

    2011-01-01

    Surface-decoration of perovskites can strongly affect the oxygen reduction activity, and therefore is a new and promising approach to improve SOFC cathode materials. In this study, we demonstrate that a small amount of secondary phase on a (001) La 0.8Sr 0.2CoO 3-δ (LSC) surface can either significantly activate or passivate the electrode. LSC (001) microelectrodes prepared by pulsed laser deposition on a (001)-oriented yttria-stabilized zirconia (YSZ) substrate were decorated with La-, Co-, and Sr-(hydr)oxides/carbonates. "Sr"-decoration with nanoparticle coverage in the range from 50% to 80% of the LSC surface enhanced the surface exchange coefficient, k q, by an order of magnitude while "La"- decoration and "Co"-decoration led to no change and reduction in k q, respectively. Although the physical origin for the enhancement is not fully understood, results from atomic force microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy suggest that the observed k q enhancement for "Sr"-decorated surfaces can be attributed largely to catalytically active interface regions between surface Sr-enriched particles and the LSC surface. © 2011 The Royal Society of Chemistry.

  16. Antimicrobial activity of transition metal acid MoO3 prevents microbial growth on material surfaces

    International Nuclear Information System (INIS)

    Zollfrank, Cordt; Gutbrod, Kai; Wechsler, Peter; Guggenbichler, Josef Peter

    2012-01-01

    Serious infectious complications of patients in healthcare settings are often transmitted by materials and devices colonised by microorganisms (nosocomial infections). Current strategies to generate material surfaces with an antimicrobial activity suffer from the consumption of the antimicrobial agent and emerging multidrug-resistant pathogens amongst others. Consequently, materials surfaces exhibiting a permanent antimicrobial activity without the risk of generating resistant microorganisms are desirable. This publication reports on the extraordinary efficient antimicrobial properties of transition metal acids such as molybdic acid (H 2 MoO 4 ), which is based on molybdenum trioxide (MoO 3 ). The modification of various materials (e.g. polymers, metals) with MoO 3 particles or sol–gel derived coatings showed that the modified materials surfaces were practically free of microorganisms six hours after contamination with infectious agents. The antimicrobial activity is based on the formation of an acidic surface deteriorating cell growth and proliferation. The application of transition metal acids as antimicrobial surface agents is an innovative approach to prevent the dissemination of microorganisms in healthcare units and public environments. Highlights: ► The presented modifications of materials surfaces with MoO 3 are non-cytotoxic and decrease biofilm growth and bacteria transmission. ► The material is insensitive towards emerging resistances of bacteria. ► Strong potential to reduce spreading of infectious agents on inanimate surfaces.

  17. [Functional recovery after recurrent laryngeal nerve injury on different electromyography thresholds during thyroid surgery].

    Science.gov (United States)

    Liu, X L; Li, C L; Zhao, Y S; Sun, H

    2017-11-01

    Objective: To discuss the functional recovery after recurrent laryngeal nerve injury (RLNI) on different electromyography thresholds during thyroid surgery. Methods: The prospective experimentally were induced in 12 acute recurrent laryngeal traction animals (porcine) from December 2014 to December 2015, the amplitude and latency of electromyography, even time course during RLNI and recovery of 24 recurrent laryngeal nerves(RLN) were continuous intraoperative neuromonitoring(IONM), including 12 RLN releasing traction after 50% amplitude decrease (AD) and other 12 RLN after 70% AD. The IONM data and postoperative laryngoscopy result of 1 119 thyroid cancer patients, involved 237 male and 882 female, aged 45.2 years in average, who underwent thyroidectomy in Department of Thyroid Surgery, China-Japan Union Hospital Affiliated to Jilin University from July to December in 2016 were analyzed retrospectively. Results: The porcine model of traction lesion showed that the time of 50% AD was (59±4) s, latency increase (LI) was (8± 4)%, was recovered in 10 minutes; the time of 70% AD was (75±6)s, LI was (11±5)% , was recovered (43±23)% of baseline even during 20 minutes. Among the IONM of 1 632 recurrent laryngeal nerves in clinic, the mechanism of 64 RLNI is clear, including traction injury accounted for 62.5% (40/64), thermal injury was 12.5% (8/64), compression injury was 23.4% (15/64), clamp injury was 1.6% (1/64). When 50%≤AD injury before AD≥50% in surgery, is a more effective indicator to avoid postoperative AVCM and promote nerve function recovery.

  18. An in situ vapour phase hydrothermal surface doping approach for fabrication of high performance Co3O4 electrocatalysts with an exceptionally high S-doped active surface.

    Science.gov (United States)

    Tan, Zhijin; Liu, Porun; Zhang, Haimin; Wang, Yun; Al-Mamun, Mohammad; Yang, Hua Gui; Wang, Dan; Tang, Zhiyong; Zhao, Huijun

    2015-04-04

    A facile in situ vapour phase hydrothermal (VPH) surface doping approach has been developed for fabrication of high performance S-doped Co3O4 electrocatalysts with an unprecedentedly high surface S content (>47%). The demonstrated VPH doping approach could be useful for enrichment of surface active sites for other metal oxide electrocatalysts.

  19. Motor, affective and cognitive empathy in adolescence : Interrelations between facial electromyography and self-reported trait and state measures

    NARCIS (Netherlands)

    Van der Graaff, Jolien; Meeus, W; de Wied, Minet; van Boxtel, Anton; van Lier, Pol A C; Koot, Hans M.; Branje, Susan

    2016-01-01

    This study examined interrelations of trait and state empathy in an adolescent sample. Self-reported affective trait empathy and cognitive trait empathy were assessed during a home visit. During a test session at the university, motor empathy (facial electromyography), and self-reported affective

  20. Atmospheric-pressure plasma activation and surface characterization on polyethylene membrane separator

    Science.gov (United States)

    Tseng, Yu-Chien; Li, Hsiao-Ling; Huang, Chun

    2017-01-01

    The surface hydrophilic activation of a polyethylene membrane separator was achieved using an atmospheric-pressure plasma jet. The surface of the atmospheric-pressure-plasma-treated membrane separator was found to be highly hydrophilic realized by adjusting the plasma power input. The variations in membrane separator chemical structure were confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Chemical analysis showed newly formed carbonyl-containing groups and high surface concentrations of oxygen-containing species on the atmospheric-pressure-plasma-treated polymeric separator surface. It also showed that surface hydrophilicity primarily increased from the polar component after atmospheric-pressure plasma treatment. The surface and pore structures of the polyethylene membrane separator were examined by scanning electron microscopy, revealing a slight alteration in the pore structure. As a result of the incorporation of polar functionalities by atmospheric-pressure plasma activation, the electrolyte uptake and electrochemical impedance of the atmospheric-pressure-plasma-treated membrane separator improved. The investigational results show that the separator surface can be controlled by atmospheric-pressure plasma surface treatment to tailor the hydrophilicity and enhance the electrochemical performance of lithium ion batteries.

  1. Surface strontium enrichment on highly active perovskites for oxygen electrocatalysis in solid oxide fuel cells

    KAUST Repository

    Crumlin, Ethan J.

    2012-01-01

    Perovskite oxides have high catalytic activities for oxygen electrocatalysis competitive to platinum at elevated temperatures. However, little is known about the oxide surface chemistry that influences the activity near ambient oxygen partial pressures, which hampers the design of highly active catalysts for many clean-energy technologies such as solid oxide fuel cells. Using in situ synchrotron-based, ambient pressure X-ray photoelectron spectroscopy to study the surface chemistry changes, we show that the coverage of surface secondary phases on a (001)-oriented La 0.8Sr 0.2CoO 3-δ (LSC) film becomes smaller than that on an LSC powder pellet at elevated temperatures. In addition, strontium (Sr) in the perovskite structure enriches towards the film surface in contrast to the pellet having no detectable changes with increasing temperature. We propose that the ability to reduce surface secondary phases and develop Sr-enriched perovskite surfaces of the LSC film contributes to its enhanced activity for O 2 electrocatalysis relative to LSC powder-based electrodes. © 2012 The Royal Society of Chemistry.

  2. Protein-Nanoparticle Interactions: Improving Immobilized Lytic Enzyme Activity and Surface Energy Effects

    Science.gov (United States)

    Downs, Emily Elizabeth

    Protein-nanostructure conjugates, particularly particles, are a subject of significant interest due to changes in their fundamental behavior compared to bulk surfaces. As the size scale of nano-structured materials and proteins are on the same order of magnitude, nanomaterial properties can heavily influence how proteins adsorb and conform to the surface. Previous work has demonstrated the ability of nanoscale surfaces to modulate protein activity, conformation, and retention by modifying the particle surface curvature, morphology, and surface charge. This work has improved our understanding of the protein material interactions, but a complete understanding is still lacking. The goal of this thesis is to investigate two missing areas of understanding using two distinct systems. The first system utilizes a particle with controlled surface energy to observe the impact of surface energy on protein-particle interactions, while the second system uses a modified Listeria-specific protein to determine how protein structure and flexibility affects protein adsorption and activity on particles. Spherical, amorphous, and uniformly doped Zn-silica particles with tailored surface energies were synthesized to understand the impact of surface energy on protein adsorption behavior. Particle surface energy increased with a decrease in particle size and greater dopant concentrations. Protein adsorption and structural loss increased with both particle size and particle surface energy. Higher surface energies promoted protein-particle association and increased protein unfolding. Particle curvature and protein steric hindrance effects limited adsorption and structural loss on smaller particles. Protein surface charge heterogeneity was also found to be linked to both protein adsorption and unfolding behavior on larger particles. Greater surface charge heterogeneity led to higher adsorption concentrations and multilayer formation. These multilayers transitioned from protein

  3. Surface characterization of activated chalcopyrite particles via the FLSmidth ROL process. Part 1: Electron microscope investigations

    DEFF Research Database (Denmark)

    Karcz, Adam Paul; Damø, Anne Juul; Illerup, Jytte Boll

    of copper(II) to dope the semiconductor lattice and thereby "activate" the chalcopyrite, thereby reducing leach times below 2 hours (>98% recovery). Because the activation plays a major role in accelerating the leaching step, it is critical to understand the nature of this intermediate and its part...... in the ROL process. The current work presents results from electron microscope investigations of surface-activated particles....

  4. Electromyography (EMG) analysis on impact of classroom chair and table usage among primary school students in Perlis

    Science.gov (United States)

    Jing, Ewe Hui; Shan, Lim Shaiu; Effendi, M. S. M.; Rosli, Muhamad Farizuan

    2017-09-01

    The existing design of primary school classroom chair and table had brought low back pain, neck pain and shoulder pain problems respectively among students in primary school. The purpose of this study is to relate the electromyography (EMG) analysis with the most critical area of the body during sitting and writing. Six male and six female primary school students from SK Seri Perlis with no back pain, neck pain and shoulder pain problems involved were invited as respondents in this study. EMG experiment was carried out by first determined the critical point at T9 and L3 from thoracic and lumbar segment respectively for ECG electrode placement and performed with a series of sitting trials for analysis. The sitting trials performed were slouch to lumbopelvic sitting and slouch to thoracic sitting follow by instruction. Next, the electrode placement was identified at C2-C3 on cervical spine for neck and at midpoint between C7 to the lateral edge of acromion spanning for shoulder respectively. These points were identified for a series of writing task performing for the EMG analysis. There were two type of writing task which included writing by looking at the whiteboard and paper placed on the table. The subjects were instructed to rest during the experiment when necessary. During lumbopelvic sitting posture, the average muscle activation on lumbar area was at the highest peak. The peak indicated that there was critical effect from the experimental finding. The performance of writing task from whiteboard gave rise a higher impact on neck muscle while writing task from paper had a greater impact on shoulder muscle. The critical affected muscle on these areas was proven on these written tasks. The EMG experiment showed that the existing design of primary school classroom chair and table had brought impact on lumbar, neck and shoulder towards the students who were using. A future recommendation suggests that to redesign primary school classroom chair and table which

  5. Processing method and processing device for liquid waste containing surface active agent and radioactive material

    International Nuclear Information System (INIS)

    Nishi, Takashi; Matsuda, Masami; Baba, Tsutomu; Yoshikawa, Ryozo; Yukita, Atsushi.

    1998-01-01

    Washing liquid wastes containing surface active agents and radioactive materials are sent to a deaerating vessel. Ozone is blown into the deaerating vessel. The washing liquid wastes dissolved with ozone are introduced to a UV ray irradiation vessel. UV rays are irradiated to the washing liquid wastes, and hydroxy radicals generated by photodecomposition of dissolved ozone oxidatively decompose surface active agents contained in the washing liquid wastes. The washing liquid wastes discharged from the UV ray irradiation vessel are sent to an activated carbon mixing vessel and mixed with powdery activated carbon. The surface active agents not decomposed in the UV ray irradiation vessel are adsorbed to the activated carbon. Then, the activated carbon and washing liquid wastes are separated by an activated carbon separating/drying device. Radioactive materials (iron oxide and the like) contained in the washing liquid wastes are mostly granular, and they are separated and removed from the washing liquid wastes in the activated carbon separating/drying device. (I.N.)

  6. [Effect of Dry Needling Stimulation of Myofascial Trigger Point on Sample Entropy of Electromyography of Gastrocnemius Injured Site in Rats].

    Science.gov (United States)

    Ding, Chen-Li; Ma, Yan-Tao; Huang, Qiang-Min; Liu, Qing-Guang; Zhao, Jia-Min

    2018-02-25

    To attempt to establish an objective quantitative indicator to characterize the trigger point activity, so as to evaluate the effect of dry needling on myofascial trigger point activity. Twenty-four male Sprague-Dawley rats were randomly divided into blank control group, dry needling (needling) group, stretching exercise (stretching) group and needling plus stretching group ( n =6 per group). The chronic myofascial pain (trigger point) model was established by freedom vertical fall of a wooden striking device onto the mid-point of gastrocnemius belly of the left hind-limb to induce contusion, followed by forcing the rat to make a continuous downgrade running exercise at a speed of 16 m/min for 90 min on the next day which was conducted once a week for 8 weeks. Electromyography (EMG) of the regional myofascial injured point was monitored and recorded using an EMG recorder via electrodes. It was considered success of the model if spontaneous electrical activities appeared in the injured site. After a 4 weeks' recovery, rats of the needling group were treated by filiform needle stimulation (lifting-thrusting-rotating) of the central part of the injured gastrocnemius belly (about 10 mm deep) for 6 min, and those of the stretching group treated by holding the rat's limb to make the hip and knee joints to an angle of about 180°, and the ankle-joint about 90° for 1 min every time, 3 times altogether (with an interval of 1 min between every 2 times). The activity of the trigger point was estimated by the sample entropy of the EMG signal sequence in reference to Richman's and Moorman's methods to estimate the curative effect of both needling and exercise. After the modeling cycle, the mean sample entropies of EMG signals was significantly decreased in the model groups (needling group [0.034±0.010], stretching group [0.045±0.023], needling plus stretching group [0.047±0.034]) relevant to the blank control group (0.985±0.196, P 0.05), suggesting a better efficacy of

  7. Adsorption of active ingredients of surface disinfectants depends on the type of fabric used for surface treatment.

    Science.gov (United States)

    Bloss, R; Meyer, S; Kampf, G

    2010-05-01

    The disinfection of surfaces in the immediate surrounding of a hospitalised patient is considered to be an important element for prevention of nosocomial infection. The type of fabric in a mop, however, has to our knowledge never been regarded as relevant for an effective disinfection of surfaces. We have therefore studied the adsorption of benzalkonium chloride (BAC), glutardialdehyde and propan-1-ol from working solutions of three surface disinfectants to four different types of fabric (A: white pulp and polyester; B: viscose rayon; C: polyester; D: mixture of viscose, cellulose and polyester). The working solutions of each disinfectant were exposed to each fabric for up to 24h. Before and after exposure, tissues were removed and squeezed in a standardised way. The eluate was used for determination of the concentration of the active ingredient in quadruplicate. The analysis of glutardialdehyde and BAC was performed using high performance liquid chromatography; the analysis of propan-1-ol was done using gas chromatography. BAC was strongly adsorbed to the tissues based on white pulp (up to 61% after 30 min), followed by the viscose rayon tissues (up to 70% after 30 min) and the mixed tissues (up to 54% after 7h). The polyester fibre tissue adsorbed the smallest amounts of BAC with up to 17% after 15 min. Only with the polyester fibre tissue were BAC concentrations found in the range of the calculated BAC concentrations. Glutardialdehyde and propan-1-ol did not adsorb to any of the fibres. Effective surface disinfection also includes selection of an appropriate fabric. Copyright (c) 2009 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

  8. Electrocatalytic activity of surface adsorbed ruthenium-alizarin complexone toward the oxidation of benzyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Aldalea Lopes Brandes; Li Weihua; Marques, Edmar Pereira; Zhang Jiujun

    2004-03-01

    The surface electrochemical behavior of an adsorbed alizarin complexone (abbreviated as AC) and its surface coordination with Ru(II) were studied in aqueous solution at a pH range of 0-6. The surface complex of ruthenium with AC displays strong electrocatalytic activities toward benzyl alcohol. Based on the rotating disk electrode measurement, it is believed that the electrocatalytic oxidation of benzyl alcohol is a two-electron and two-proton process with benzaldehyde as a major product. On the other hand, ruthenium-AC surface complex has also shown catalytic activities toward electro-oxidation of several small organic molecules such as methanol, formic acid, formaldehyde, ethanol, and acetaldehyde.

  9. Peculiar surface behavior of some ionic liquids based on active pharmaceutical ingredients.

    Science.gov (United States)

    Restolho, José; Mata, José Luis; Saramago, Benilde

    2011-02-21

    The ionic liquids based on biologically active cations and anions, commonly designated by ionic liquids based on active pharmaceutical ingredients (ILs-APIs), are interesting compounds for use in pharmaceutical applications. Lidocaine docusate, ranitidine docusate, and didecyldimethylammonium ibuprofen are examples of promising ILs-APIs that were recently synthesized. They were submitted to biological testing and calorimetric measurements, but nothing is known about their surface properties. In this work, we measured the surface tension and the contact angles on both hydrophilic and hydrophobic surfaces in a temperature range as wide as possible. Based on the wettability data, the polarity fractions were estimated using the Fowkes theory. The peculiar surface behavior observed was tentatively attributed to the presence of mesophases.

  10. Peculiar surface behavior of some ionic liquids based on active pharmaceutical ingredients

    Science.gov (United States)

    Restolho, José; Mata, José Luis; Saramago, Benilde

    2011-02-01

    The ionic liquids based on biologically active cations and anions, commonly designated by ionic liquids based on active pharmaceutical ingredients (ILs-APIs), are interesting compounds for use in pharmaceutical applications. Lidocaine docusate, ranitidine docusate, and didecyldimethylammonium ibuprofen are examples of promising ILs-APIs that were recently synthesized. They were submitted to biological testing and calorimetric measurements, but nothing is known about their surface properties. In this work, we measured the surface tension and the contact angles on both hydrophilic and hydrophobic surfaces in a temperature range as wide as possible. Based on the wettability data, the polarity fractions were estimated using the Fowkes theory. The peculiar surface behavior observed was tentatively attributed to the presence of mesophases.

  11. Muscle activity in sprinting: a review.

    Science.gov (United States)

    Howard, Róisín M; Conway, Richard; Harrison, Andrew J

    2018-03-01

    The use of electromyography (EMG) is widely recognised as a valuable tool for enhancing the understanding of performance drivers and potential injury risk in sprinting. The timings of muscle activations relative to running gait cycle phases and the technology used to obtain muscle activation data during sprinting are of particular interest to scientists and coaches. This review examined the main muscles being analysed by surface EMG (sEMG), their activations and timing, and the technologies used to gather sEMG during sprinting. Electronic databases were searched using 'Electromyography' OR 'EMG' AND 'running' OR 'sprinting'. Based on inclusion criteria, 18 articles were selected for review. While sEMG is widely used in biomechanics, relatively few studies have used sEMG in sprinting due to system constraints. The results demonstrated a focus on the leg muscles, with over 70% of the muscles analysed in the upper leg. This is consistent with the use of tethered and data logging EMG systems and many sprints being performed on treadmills. Through the recent advances in wireless EMG technology, an increase in the studies on high velocity movements such as sprinting is expected and this should allow practitioners to perform the analysis in an ecologically valid environment.

  12. Laboratory Activity Worksheet to Train High Order Thinking Skill of Student on Surface Chemistry Lecture

    Science.gov (United States)

    Yonata, B.; Nasrudin, H.

    2018-01-01

    A worksheet has to be a set with activity which is help students to arrange their own experiments. For this reason, this research is focused on how to train students’ higher order thinking skills in laboratory activity by developing laboratory activity worksheet on surface chemistry lecture. To ensure that the laboratory activity worksheet already contains aspects of the higher order thinking skill, it requires theoretical and empirical validation. From the data analysis results, it shows that the developed worksheet worth to use. The worksheet is worthy of theoretical and empirical feasibility. This conclusion is based on the findings: 1) Assessment from the validators about the theoretical feasibility aspects in the category is very feasible with an assessment range of 95.24% to 97.92%. 2) students’ higher thinking skill from N Gain values ranges from 0.50 (enough) to 1.00 (high) so it can be concluded that the laboratory activity worksheet on surface chemistry lecture is empirical in terms of worth. The empirical feasibility is supported by the responses of the students in very reasonable categories. It is expected that the laboratory activity worksheet on surface chemistry lecture can train students’ high order thinking skills for students who program surface chemistry lecture.

  13. Study of Hexane Adsorption on Activated Carbons with Differences in Their Surface Chemistry.

    Science.gov (United States)

    Hernández-Monje, Diana; Giraldo, Liliana; Moreno-Piraján, Juan Carlos

    2018-02-22

    The study of aliphatic compounds adsorption on activated carbon can be carried out from the energetic change involved in the interaction; the energy values can be determined from isotherms or by the immersion enthalpy. Vapor phase adsorption isotherms of hexane at 263 K on five activated carbons with different content of oxygenated groups and the immersion enthalpy of the activated carbons in hexane and water were determined in order to characterize the interactions in the solid-liquid system, and for calculating the hydrophobic factor of the activated carbons. The micropore volume and characteristic energy from adsorption isotherms of hexane, the BET (Brunauer-Emmett-Teller) surface area from the adsorption isotherms of N₂, and the area accessible to the hexane from the immersion enthalpy were calculated. The activated carbon with the lowest content of oxygenated groups (0.30 µmolg - ¹) and the highest surface area (996 m²g - ¹) had the highest hexane adsorption value: 0.27 mmol g - ¹; the values for E o were between 5650 and 6920 Jmol - ¹ and for ΔH im were between -66.1 and -16.4 Jg - ¹. These determinations allow us to correlate energetic parameters with the surface area and the chemical modifications that were made to the solids, where the surface hydrophobic character of the activated carbon favors the interaction.

  14. Effects of jump and balance training on knee kinematics and electromyography of female basketball athletes during a single limb drop landing: pre-post intervention study

    Directory of Open Access Journals (Sweden)

    Nagano Yasuharu

    2011-07-01

    Full Text Available Abstract Background Some research studies have investigated the effects of anterior cruciate ligament (ACL injury prevention programs on knee kinematics during landing tasks; however the results were different among the studies. Even though tibial rotation is usually observed at the time of ACL injury, the effects of training programs for knee kinematics in the horizontal plane have not yet been analyzed. The purpose of this study was to determine the effects of a jump and balance training program on knee kinematics including tibial rotation as well as on electromyography of the quadriceps and hamstrings in female athletes. Methods Eight female basketball athletes participated in the experiment. All subjects performed a single limb landing at three different times: the initial test, five weeks later, and one week after completing training. The jump and balance training program lasted for five weeks. Knee kinematics and simultaneous electromyography of the rectus femoris and Hamstrings before training were compared with those measured after completing the training program. Results After training, regarding the position of the knee at foot contact, the knee flexion angle for the Post-training trial (mean (SE: 24.4 (2.1 deg was significantly larger than that for the Pre-training trial (19.3 (2.5 deg (p Conclusions The jump and balance training program successfully increased knee flexion and hamstring activity of female athletes during landing, and has the possibility of producing partial effects to avoid the characteristic knee position observed in ACL injury, thereby preventing injury. However, the expected changes in frontal and transverse kinematics of the knee were not observed.

  15. An investigation of the functional groups on the surface of activated carbons

    Directory of Open Access Journals (Sweden)

    MARYTE DERVINYTE

    2004-05-01

    Full Text Available Activated carbons were produced in the laboratory from wood using a 20-run Plackett–Burman experimental design for 19 factors. The obtained batches of activated carbon were analysed by potentiometric titration and FTIR spectroscopy to determine the surface functional groups. The results obtained by potentiometric titration displayed the distribution of individual acidity constants of those groups in the pK range. Considering this parameter, the surface functional groups were divided into carboxyl, lactone and phenol. The linear regression equations reflecting the influence of each operation used for the synthesis on the amount of these functional groups in the obtained activated carbons were generated. The FTIR spectra were used in parallel for the evaluation of the amount and the type of the surface functional groups. Relationships between the two data sets obtained by potentiometric titration and FTIR spectroscopy were evaluated by correlation analysis. It was established that the amount of surface functional groups determined by potentiometric titration positively correlates with the intensity of the peaks of hydrophilic functional groups in the FTIR spectra. At the same time, the negative correlation between potentiometrically determined amount of surface functional groups and the intensity of peaks of hydrophobic functional groups was observed. Most probably, these non-polar formations can take part in the interaction of carbon surface with H+/OH- ions and diminish the strength of existent functional groups.

  16. Cavitand-functionalized porous silicon as an active surface for organophosphorus vapor detection.

    Science.gov (United States)

    Tudisco, Cristina; Betti, Paolo; Motta, Alessandro; Pinalli, Roberta; Bombaci, Luigi; Dalcanale, Enrico; Condorelli, Guglielmo G

    2012-01-24

    This paper reports on the preparation of a porous silicon-based material covalently functionalized with cavitand receptors suited for the detection of organophosphorus vapors. Two different isomeric cavitands, both containing one acid group at the upper rim, specifically designed for covalent anchoring on silicon, were grafted on H-terminated porous silicon (PSi) by thermal hydrosilylation. The covalently functionalized surfaces and their complexation properties were characterized by combining different analytical techniques, namely X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and mass spectroscopy analysis coupled with thermal desorption experiments. Complexation experiments were performed by exposing both active surfaces and a control surface consisting of PSi functionalized with a structurally similar but inactive methylene-bridged cavitand (MeCav) to dimethyl methylphosphonate (DMMP) vapors. Comparison between active and inactive surfaces demonstrated the recognition properties of the new surfaces. Finally, the nature of the involved interactions, the energetic differences between active and inactive surfaces toward DMMP complexation, and the comparison with a true nerve gas agent (sarin) were studied by DFT modeling. The results revealed the successful grafting reaction, the specific host-guest interactions of the PSi-bonded receptors, and the reversibility of the guest complexation.

  17. Surface-Bound Ligands Modulate Chemoselectivity and Activity of a Bimetallic Nanoparticle Catalyst

    KAUST Repository

    Vu, Khanh B.

    2015-04-03

    "Naked" metal nanoparticles (NPs) are thermodynamically and kinetically unstable in solution. Ligands, surfactants, or polymers, which adsorb at a particle\\'s surface, can be used to stabilize NPs; however, such a mode of stabilization is undesirable for catalytic applications because the adsorbates block the surface active sites. The catalytic activity and the stability of NPs are usually inversely correlated. Here, we describe an example of a bimetallic (PtFe) NP catalyst stabilized by carboxylate surface ligands that bind preferentially to one of the metals (Fe). NPs stabilized by fluorous ligands were found to be remarkably competent in catalyzing the hydrogenation of cinnamaldehyde; NPs stabilized by hydrocarbon ligands were significantly less active. The chain length of the fluorous ligands played a key role in determining the chemoselectivity of the FePt NP catalysts. (Chemical Presented). © 2015 American Chemical Society.

  18. Autoinducer-2 activity produced by bacteria found in smear of surface ripened cheeses

    DEFF Research Database (Denmark)

    Gori, Klaus; Moslehi Jenabian, Saloomeh; Purrotti, Micol

    2011-01-01

    Bacterial strains of the species Arthrobacter nicotianae, Corynebacterium ammoniagenes, Corynebacterium casei, Microbacterium barkeri, Microbacterium gubbeenense and Staphylococcus equorum subsp. linens, all isolated from the smear of surface ripened cheeses, were found to possess autoinducer-2 (...... increased by dairy-relevant stress conditions, indicates that AI-2 signalling might be important in regulation of microbial succession during ripening of surface ripened cheeses.......Bacterial strains of the species Arthrobacter nicotianae, Corynebacterium ammoniagenes, Corynebacterium casei, Microbacterium barkeri, Microbacterium gubbeenense and Staphylococcus equorum subsp. linens, all isolated from the smear of surface ripened cheeses, were found to possess autoinducer-2 (AI......-2) activity using the Vibrio harveyi (BB170) bioluminescence assay. In contrast, Brevibacterium casei and Brevibacterium linens strains were not found to have AI-2 activity. When exposed to low pH and high NaCl concentrations, AI-2 activities increased between 5.0 and 11.6× for C. casei 44701, M...

  19. Preparation of self-cleaning surfaces with a dual functionality of superhydrophobicity and photocatalytic activity

    Science.gov (United States)

    Park, Eun Ji; Yoon, Hye Soo; Kim, Dae Han; Kim, Yong Ho; Kim, Young Dok

    2014-11-01

    Thin film of polydimethylsiloxane (PDMS) was deposited on SiO2 nanoparticles by chemical vapor deposition, and SiO2 became completely hydrophobic after PDMS coating. Mixtures of TiO2 and PDMS-coated SiO2 nanoparticles with various relative ratios were prepared, and distributed on glass surfaces, and water contact angles and photocatalytic activities of these surfaces were studied. Samples consisting of TiO2 and PDMS-coated SiO2 with a ratio of 7:3 showed a highly stable superhydrophobicity under UV irradiation with a water contact angle of 165° and UV-driven photocatalytic activity for decomposition of methylene blue and phenol in aqueous solution. Our process can be exploited for fabricating self-cleaning surfaces with dual functionality of superhydrophobicity and photocatalytic activity at the same time.

  20. Simultaneous surface and depth neural activity recording with graphene transistor-based dual-modality probes.

    Science.gov (United States)

    Du, Mingde; Xu, Xianchen; Yang, Long; Guo, Yichuan; Guan, Shouliang; Shi, Jidong; Wang, Jinfen; Fang, Ying

    2018-05-15

    Subdural surface and penetrating depth probes are widely applied to record neural activities from the cortical surface and intracortical locations of the brain, respectively. Simultaneous surface and depth neural activity recording is essential to understand the linkage between the two modalities. Here, we develop flexible dual-modality neural probes based on graphene transistors. The neural probes exhibit stable electrical performance even under 90° bending because of the excellent mechanical properties of graphene, and thus allow multi-site recording from the subdural surface of rat cortex. In addition, finite element analysis was carried out to investigate the mechanical interactions between probe and cortex tissue during intracortical implantation. Based on the simulation results, a sharp tip angle of π/6 was chosen to facilitate tissue penetration of the neural probes. Accordingly, the graphene transistor-based dual-modality neural probes have been successfully applied for simultaneous surface and depth recording of epileptiform activity of rat brain in vivo. Our results show that graphene transistor-based dual-modality neural probes can serve as a facile and versatile tool to study tempo-spatial patterns of neural activities. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Evaluation of Foaming Performance of Bitumen Modified with the Addition of Surface Active Agent

    Science.gov (United States)

    Chomicz-Kowalska, Anna; Mrugała, Justyna; Maciejewski, Krzysztof

    2017-10-01

    The article presents the analysis of the performance of foamed bitumen modified using surface active agents. Although, bitumen foaming permits production of asphalt concrete and other asphalt mix types without using chemical additives in significantly reduced temperatures, the decrease in processing temperatures still impacts the adhesion performance and bitumen coating of aggregates in final mixes. Therefore, in some cases it may be feasible to incorporate adhesion promoters and surface active agents into warm and half-warm mixes with foamed bitumen to increase their service life and resilience. Because of the various nature of the available surface active agents, varying bitumen compatibility and their possible impact on the rheological properties of bitumen, the introduction of surface active agents may significantly alter the bitumen foaming performance. The tests included basic performance tests of bitumen before and after foaming. The two tested bitumen were designated as 35/50 and 50/70 penetration grade binders, which were modified with a surface active agent widely used for improving mixture workability, compactibility and adhesion in a wide range of asphalt mixes and techniques, specifically Warm Mix Asphalt. Alongside to the reference unmodified bitumen, binders with 0.2%, 0.4% and 0.6% surface active agent concentration were tested. The analysis has shown a positive influence of the modifier on the foaming performance of both of the base bitumen increasing their maximum expansion ratio and bitumen foam halflife. In the investigations, it was found that the improvement was dependent on the bitumen type and modifier content. The improved expansion ratio and foam half-life has a positive impact on the aggregate coating and adhesion, which together with the adhesion promoting action of the modifier will have a combined positive effect on the quality of produced final asphalt mixes.

  2. Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

    International Nuclear Information System (INIS)

    Sych, N.V.; Trofymenko, S.I.; Poddubnaya, O.I.; Tsyba, M.M.; Sapsay, V.I.; Klymchuk, D.O.; Puziy, A.M.

    2012-01-01

    Highlights: ► Phosphoric acid activation results in formation of carbons with acidic surface groups. ► Maximum amount of surface groups is introduced at impregnation ratio 1.25. ► Phosphoric acid activated carbons show high capacity to copper. ► Phosphoric acid activated carbons are predominantly microporous. ► Maximum surface area and pore volume achieved at impregnation ratio 1.0. - Abstract: Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 °C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (S BET = 2081 m 2 /g, V tot = 1.1 cm 3 /g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0–2.6), weakly acidic carboxylic (pK = 4.7–5.0), enol/lactone (pK = 6.7–7.4; 8.8–9.4) and phenol (pK = 10.1–10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

  3. Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

    Energy Technology Data Exchange (ETDEWEB)

    Sych, N.V.; Trofymenko, S.I.; Poddubnaya, O.I.; Tsyba, M.M. [Institute for Sorption and Endoecology Problems, National Academy of Sciences of Ukraine, 13 General Naumov St., 03164 Kyiv (Ukraine); Sapsay, V.I.; Klymchuk, D.O. [M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, 2 Tereshchenkivska St., 01601 Kyiv (Ukraine); Puziy, A.M., E-mail: alexander.puziy@ispe.kiev.ua [Institute for Sorption and Endoecology Problems, National Academy of Sciences of Ukraine, 13 General Naumov St., 03164 Kyiv (Ukraine)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Phosphoric acid activation results in formation of carbons with acidic surface groups. Black-Right-Pointing-Pointer Maximum amount of surface groups is introduced at impregnation ratio 1.25. Black-Right-Pointing-Pointer Phosphoric acid activated carbons show high capacity to copper. Black-Right-Pointing-Pointer Phosphoric acid activated carbons are predominantly microporous. Black-Right-Pointing-Pointer Maximum surface area and pore volume achieved at impregnation ratio 1.0. - Abstract: Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 Degree-Sign C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (S{sub BET} = 2081 m{sup 2}/g, V{sub tot} = 1.1 cm{sup 3}/g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0-2.6), weakly acidic carboxylic (pK = 4.7-5.0), enol/lactone (pK = 6.7-7.4; 8.8-9.4) and phenol (pK = 10.1-10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

  4. Surface-active and electrophysical semiconductors properties of the CdTe-CdSe system

    Science.gov (United States)

    Kirovskaya, I. A.; Bukashkina, T. L.; Ekkert, R. V.; Ushakov, O. V.; Kolesnikov, L. V.; Matyash, Yu I.

    2018-01-01

    Surface properties (acid-base, adsorptive, electrophysical) of binary and multicomponent semiconductors of the CdTe-CdSe system have been holistically studied. Changing patterns of the studied surface properties correlated among themselves and with changing patterns of the bulk physical and chemical properties have been revealed. The nature of active centers, acid-base, adsorptive and electronic interactions mechanisms have been determined with due account for local and collective factors The most active discovered adsorbents are recommended as primary transducers of CO trace impurities measuring cells.

  5. Effect of machining on the deformability of steel in surface-active medium at lower temperatures

    International Nuclear Information System (INIS)

    Gusti, E.Ya.; Babej, Yu.I.

    1977-01-01

    The effect of some machining methods of carbon steel, chromium steel, and chromium nickel steel, and that of low temperatures on the principle characteristics of formability during impact bending in air and a surface-active environment have been studied. The temperature decrease from the ambient to -80 deg is shown to reduce steel formability as evaluated by deflection (f) and to increase the forming force. The variation of these characteristics with lowering temperature, however, is greatly affected by machining process conditions. The FRHT (Friction-Hardening Treatment) on the white layer assures minimum ductility losses, and increases steel strength at low temperatures both in air and in the surface-active environment

  6. Poisoning the active site of electrochemical reduction of dioxygen on metal monolayer modified electrode surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Oh, I.; Biggin, M.E.; Gewirth, A.A.

    2000-02-08

    The four electron electroreduction of dioxygen to water on the (2 x 2) Bi upd adlattice on Au(111) has been studied by deliberately poisoning the adlattice with thiocyanate and ethanethiol during the course of electroreduction activity. The diminution in reduction activity was monitored using chronoamperometry. For SCN{sup {minus}}, the drop in current could be modeled using a Langmuir kinetic expression yielding an adsorption rate constant of 1.1 x 10{sup 4}s{sup {minus}1}M{sup {minus}1}. The rate for ethanethiol could not be measured exactly but is approximately the same. STM images of the surface obtained following introduction of SCN{sup {minus}} revealed a (4 x 4) adlattice, which was partially (6%) defected. The percentage of defects agreed well with the percentage of residual current found at long times (3%) leading the authors to associate these defects with sites of catalytic activity. STM images obtained from surfaces poisoned with ethanethiol revealed two lattices: a (8 x 8) structure which was unstable and a more stable ({radical}57 x 3) structure which is consistent with an overlayer of thiols lying flat on the surface. IR studies of the SCN{sup {minus}}-poisoned surface showed that the SCN{sup {minus}} was S-bound to the surface at almost the same energy as that expected from SCN{sup {minus}} bound to a bare Au(111) surface. XPS measurements on emersed samples showed that Bi and S were present on the surface. Analysis of these data suggests that the site of dioxygen association with the (2 x 2) Bi unpoisoned surface is the uncoordinated Au atom in the (2 x 2) unit cell.

  7. Surface tension prevails over solute effect in organic-influenced cloud droplet activation

    Science.gov (United States)

    Ovadnevaite, Jurgita; Zuend, Andreas; Laaksonen, Ari; Sanchez, Kevin J.; Roberts, Greg; Ceburnis, Darius; Decesari, Stefano; Rinaldi, Matteo; Hodas, Natasha; Facchini, Maria Cristina; Seinfeld, John H.; O' Dowd, Colin

    2017-06-01

    The spontaneous growth of cloud condensation nuclei (CCN) into cloud droplets under supersaturated water vapour conditions is described by classic Köhler theory. This spontaneous activation of CCN depends on the interplay between the Raoult effect, whereby activation potential increases with decreasing water activity or increasing solute concentration, and the Kelvin effect, whereby activation potential decreases with decreasing droplet size or increases with decreasing surface tension, which is sensitive to surfactants. Surface tension lowering caused by organic surfactants, which diminishes the Kelvin effect, is expected to be negated by a concomitant reduction in the Raoult effect, driven by the displacement of surfactant molecules from the droplet bulk to the droplet-vapour interface. Here we present observational and theoretical evidence illustrating that, in ambient air, surface tension lowering can prevail over the reduction in the Raoult effect, leading to substantial increases in cloud droplet concentrations. We suggest that consideration of liquid-liquid phase separation, leading to complete or partial engulfing of a hygroscopic particle core by a hydrophobic organic-rich phase, can explain the lack of concomitant reduction of the Raoult effect, while maintaining substantial lowering of surface tension, even for partial surface coverage. Apart from the importance of particle size and composition in droplet activation, we show by observation and modelling that incorporation of phase-separation effects into activation thermodynamics can lead to a CCN number concentration that is up to ten times what is predicted by climate models, changing the properties of clouds. An adequate representation of the CCN activation process is essential to the prediction of clouds in climate models, and given the effect of clouds on the Earth’s energy balance, improved prediction of aerosol-cloud-climate interactions is likely to result in improved assessments of future

  8. New Concept of C–H and C–C Bond Activation via Surface Organometallic Chemistry

    KAUST Repository

    Samantaray, Manoja

    2015-08-18

    In this chapter we describe the recent applications of well-defined oxidesupported metal alkyls/alkylidenes/alkylidynes and hydrides of group IV, V, and VI transition metals in the field of C–H and C–C bond activation. The activation of ubiquitous C–H and C–C bonds of paraffin is a long-standing challenge because of intrinsic low reactivity. There are many concepts derived from surface organometallic chemistry (SOMC): surface organometallic fragments are always intermediates in heterogeneous catalysis. The study of their synthesis and reactivity is a way to rationalize mechanism of heterogeneous catalysis and to achieve structure activity relationship. By surface organometallic chemistry one can enter any catalytic center by a reaction intermediate leading in fine to single site catalysts. With surface organometallic chemistry one can coordinate to the metal which can play a role in different elementary steps leading for example to C–H activation and Olefin metathesis. Because of the development of SOMC there is a lot of space for the improvement of homogeneous catalysis. After the 1997 discovery of alkane metathesis using silica-supported tantalum hydride by Basset et al. at low temperature (150ºC) the focus in this area was shifted to the discovery of more and more challenging surface complexes active in the application of C–H and C–C bond activation. Here we describe the evolution of well-defined metathesis catalyst with time as well as the effect of support on catalysis. We also describe here which metal–ligand combinations are responsible for a variety of C–H and C–C bond activation.

  9. Surface tension prevails over solute effect in organic-influenced cloud droplet activation.

    Science.gov (United States)

    Ovadnevaite, Jurgita; Zuend, Andreas; Laaksonen, Ari; Sanchez, Kevin J; Roberts, Greg; Ceburnis, Darius; Decesari, Stefano; Rinaldi, Matteo; Hodas, Natasha; Facchini, Maria Cristina; Seinfeld, John H; O' Dowd, Colin

    2017-06-29

    The spontaneous growth of cloud condensation nuclei (CCN) into cloud droplets under supersaturated water vapour conditions is described by classic Köhler theory. This spontaneous activation of CCN depends on the interplay between the Raoult effect, whereby activation potential increases with decreasing water activity or increasing solute concentration, and the Kelvin effect, whereby activation potential decreases with decreasing droplet size or increases with decreasing surface tension, which is sensitive to surfactants. Surface tension lowering caused by organic surfactants, which diminishes the Kelvin effect, is expected to be negated by a concomitant reduction in the Raoult effect, driven by the displacement of surfactant molecules from the droplet bulk to the droplet-vapour interface. Here we present observational and theoretical evidence illustrating that, in ambient air, surface tension lowering can prevail over the reduction in the Raoult effect, leading to substantial increases in cloud droplet concentrations. We suggest that consideration of liquid-liquid phase separation, leading to complete or partial engulfing of a hygroscopic particle core by a hydrophobic organic-rich phase, can explain the lack of concomitant reduction of the Raoult effect, while maintaining substantial lowering of surface tension, even for partial surface coverage. Apart from the importance of particle size and composition in droplet activation, we show by observation and modelling that incorporation of phase-separation effects into activation thermodynamics can lead to a CCN number concentration that is up to ten times what is predicted by climate models, changing the properties of clouds. An adequate representation of the CCN activation process is essential to the prediction of clouds in climate models, and given the effect of clouds on the Earth's energy balance, improved prediction of aerosol-cloud-climate interactions is likely to result in improved assessments of future

  10. Surface-bound phosphatase activity in living hyphae of ectomycorrhizal fungi of Nothofagus obliqua.

    Science.gov (United States)

    Alvarez, Maricel; Godoy, Roberto; Heyser, Wolfgang; Härtel, Steffen

    2004-01-01

    We determined the location and the activity of surface-bound phosphomonoesterase (SBP) of five ectomycorrhizal (EM) fungi of Nothofagus oblique. EM fungal mycelium of Paxillus involutus, Austropaxillus boletinoides, Descolea antartica, Cenococcum geophilum and Pisolithus tinctorius was grown in media with varying concentrations of dissolved phosphorus. SBP activity was detected at different pH values (3-7) under each growth regimen. SBP activity was assessed using a colorimetric method based on the hydrolysis of p-nitrophenyl phosphate (pNPP) to p-nitrophenol phosphate (pNP) + P. A new technique involving confocal laser-scanning microscopy (LSM) was used to locate and quantify SBP activity on the hyphal surface. EM fungi showed two fundamentally different patterns of SBP activity in relation to varying environmental conditions (P-concentrations and pH). In the cases of D. antartica, A. boletinoides and C. geophilum, changes in SBP activity were induced primarily by changes in the number of SBP-active centers on the hyphae. In the cases of P. tinctorius and P. involutus, the number of SBP-active centers per μm hyphal length changed much less than the intensity of the SBP-active centers on the hyphae. Our findings not only contribute to the discussion about the role of SBP-active centers in EM fungi but also introduce LSM as a valuable method for studying EM fungi.

  11. Motion tracking and electromyography assist the removal of mirror hand contributions to fNIRS images acquired during a finger tapping task performed by children with cerebral palsy

    Science.gov (United States)

    Hervey, Nathan; Khan, Bilal; Shagman, Laura; Tian, Fenghua; Delgado, Mauricio R.; Tulchin-Francis, Kirsten; Shierk, Angela; Smith, Linsley; Reid, Dahlia; Clegg, Nancy J.; Liu, Hanli; MacFarlane, Duncan; Alexandrakis, George

    2013-03-01

    Functional neurological imaging has been shown to be valuable in evaluating brain plasticity in children with cerebral palsy (CP). In recent studies it has been demonstrated that functional near-infrared spectroscopy (fNIRS) is a viable and sensitive method for imaging motor cortex activities in children with CP. However, during unilateral finger tapping tasks children with CP often exhibit mirror motions (unintended motions in the non-tapping hand), and current fNIRS image formation techniques do not account for this. Therefore, the resulting fNIRS images contain activation from intended and unintended motions. In this study, cortical activity was mapped with fNIRS on four children with CP and five controls during a finger tapping task. Finger motion and arm muscle activation were concurrently measured using motion tracking cameras and electromyography (EMG). Subject-specific regressors were created from motion capture and EMG data and used in a general linear model (GLM) analysis in an attempt to create fNIRS images representative of different motions. The analysis provided an fNIRS image representing activation due to motion and muscle activity for each hand. This method could prove to be valuable in monitoring brain plasticity in children with CP by providing more consistent images between measurements. Additionally, muscle effort versus cortical effort was compared between control and CP subjects. More cortical effort was required to produce similar muscle effort in children with CP. It is possible this metric could be a valuable diagnostic tool in determining response to treatment.

  12. Surface modification of coconut shell based activated carbon for the improvement of hydrophobic VOC removal.

    Science.gov (United States)

    Li, Lin; Liu, Suqin; Liu, Junxin

    2011-08-30

    In this study, coconut shell based carbons were chemically treated by ammonia, sodium hydroxide, nitric acid, sulphuric acid, and phosphoric acid to determine suitable modification for improving adsorption ability of hydrophobic volatile organic compounds (VOCs) on granular activated carbons (GAC). The saturated adsorption capacities of o-xylene, a hydrophobic volatile organic compound, were measured and adsorption effects of the original and modified activated carbons were compared. Results showed that GAC modified by alkalis had better o-xylene adsorption capacity. Uptake amount was enhanced by 26.5% and reduced by 21.6% after modification by NH(3)H(2)O and H(2)SO(4), respectively. Compared with the original, GAC modified by acid had less adsorption capacity. Both SEM/EDAX and BET were used to identify the structural characteristics of the tested GAC, while IR spectroscopy and Boehm's titration were applied to analysis the surface functional groups. Relationships between physicochemical characteristics of GAC and their adsorption performances demonstrated that o-xylene adsorption capacity was related to surface area, pore volume, and functional groups of the GAC surface. Removing surface oxygen groups, which constitute the source of surface acidity, and reducing hydrophilic carbon surface favors adsorption capacity of hydrophobic VOCs on carbons. The performances of modified GACs were also investigated in the purification of gases containing complex components (o-xylene and steam) in the stream. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Modular "click" chemistry for electrochemically and photoelectrochemically active molecular interfaces to tin oxide surfaces.

    Science.gov (United States)

    Benson, Michelle C; Ruther, Rose E; Gerken, James B; Rigsby, Matthew L; Bishop, Lee M; Tan, Yizheng; Stahl, Shannon S; Hamers, Robert J

    2011-08-01

    We demonstrate the use of "click" chemistry to form electrochemically and photoelectrochemically active molecular interfaces to SnO(2) nanoparticle thin films. By using photochemical grafting to link a short-chain alcohol to the surface followed by conversion to a surface azide group, we enable use of the Cu(I)-catalyzed azide-alkyne [3 + 2] cycloaddition (CuAAC) reaction, a form of "click" chemistry, on metal oxide surfaces. Results are shown with three model compounds to test the surface chemistry and subsequent ability to achieve electrochemical and photoelectrochemical charge transfer. Surface-tethered ferrocene groups exhibit good electron-transfer characteristics with thermal rates estimated at >1000 s(-1). Time-resolved surface photovoltage measurements using a ruthenium terpyridyl coordination compound demonstrate photoelectron charge transfer on time scales of nanoseconds or less, limited by the laser pulse width. The results demonstrate that the CuAAC "click" reaction can be used to form electrochemically and photoelectrochemically active molecular interfaces to SnO(2) and other metal oxide semiconductors.

  14. Effect of plasma-induced surface charging on catalytic processes: application to CO2 activation

    Science.gov (United States)

    Bal, Kristof M.; Huygh, Stijn; Bogaerts, Annemie; Neyts, Erik C.

    2018-02-01

    Understanding the nature and effect of the multitude of plasma–surface interactions in plasma catalysis is a crucial requirement for further process development and improvement. A particularly intriguing and rather unique property of a plasma-catalytic setup is the ability of the plasma to modify the electronic structure, and hence chemical properties, of the catalyst through charging, i.e. the absorption of excess electrons. In this work, we develop a quantum chemical model based on density functional theory to study excess negative surface charges in a heterogeneous catalyst exposed to a plasma. This method is specifically applied to investigate plasma-catalytic CO2 activation on supported M/Al2O3 (M = Ti, Ni, Cu) single atom catalysts. We find that (1) the presence of a negative surface charge dramatically improves the reductive power of the catalyst, strongly promoting the splitting of CO2 to CO and oxygen, and (2) the relative activity of the investigated transition metals is also changed upon charging, suggesting that controlled surface charging is a powerful additional parameter to tune catalyst activity and selectivity. These results strongly point to plasma-induced surface charging of the catalyst as an important factor contributing to the plasma-catalyst synergistic effects frequently reported for plasma catalysis.

  15. Cd(II) removal on surface-modified activated carbon: equilibrium, kinetics and mechanism.

    Science.gov (United States)

    Liang, Jianjun; Liu, Meiling; Zhang, Yufei

    2016-10-01

    Commercial pulverous activated carbon (AC-0) was modified through two steps: oxidize AC-0 acid firstly, impregnate it with iron using ferric chloride secondly. Orthogonal experiment was conducted then to prepare modified activated carbon with high Cd(II) adsorption capacity (ACNF). Batch adsorption experiments were undertaken to determine the adsorption characteristics of Cd(II) from aqueous solution onto AC-0 and ACNF and the effect of pH, contact time and initial Cd(II) concentration. The results indicate that: the adsorption behavior of Cd(II) on ACNF can be well fitted with Langmuir model, and the maximum adsorption capacity of ACNF was 2.3 times higher than that of AC-0, supporting a monolayer coverage of Cd(II) on the surface. The kinetics of the adsorption process can be described by pseudo-second-order rate equation very well, and the adsorption capacity increased from 0.810 mg/g to 0.960 mg/g after modification. Compared with AC-0, the kinetic parameters of ACNF showed a higher adsorption rate through the aqueous solution to the solid surface and a lower intraparticle diffusion rate. Surface modification resulted in a lower Brunauer-Emmett-Teller (BET) surface area and pore size because of the collapse and blockage of pores, according to the X-ray diffraction (XRD) analysis, while the total number of surface oxygen acid groups increased, and this was supposed to contribute to the enhanced adsorption capacity of modified activated carbon.

  16. Alzheimer's amyloid precursor protein is expressed on the surface of hematopoietic cells upon activation.

    Science.gov (United States)

    Bullido, M J; Muñoz-Fernandez, M A; Recuero, M; Fresno, M; Valdivieso, F

    1996-08-21

    A4-amyloid is the major component of senile plaques and neurofibrillary tangles found in the brain of patients suffering Alzheimer's disease. This 39-42 amino acid peptide is derived from a larger precursor protein (APP). Since APP gene encodes for a putative membrane protein, the study of APP expression at the cell surface may provide useful data for understanding its physiological function. In this report, we present data on APP expression, that was detected by APP specific mAbs in cells of the hematopoietic system. APP was weakly expressed on the cell surface of resting human lymphocytes and monocytes, but it could be induced to the surface of those cells upon stimulation. The cell activators capable of inducing APP membrane expression comprehended mitogenic lectins, calcium ionophores, phosphatase inhibitors, and anti mu-chain or anti-CD3 antibodies in B and T cells, respectively. Interestingly, phorbol esters were able to induce APP membrane expression in monocytic, but not in lymphoid cells. In contrast to lymphocytes and monocytes, granulocytes never expressed cell surface or cytoplasmic APP, even after the activation. The induction of membrane APP in response to lymphocyte activation signals, including antibodies to the antigen receptor of B and T cells, raises the possibility that APP might play the role of a cell surface receptor in the immune system.

  17. Quaternary Geology and Surface Faulting Hazard: Active and Capable Faults in Central Apennines, Italy

    Science.gov (United States)

    Falcucci, E.; Gori, S.

    2015-12-01

    The 2009 L'Aquila earthquake (Mw 6.1), in central Italy, raised the issue of surface faulting hazard in Italy, since large urban areas were affected by surface displacement along the causative structure, the Paganica fault. Since then, guidelines for microzonation were drew up that take into consideration the problem of surface faulting in Italy, and laying the bases for future regulations about related hazard, similarly to other countries (e.g. USA). More specific guidelines on the management of areas affected by active and capable faults (i.e. able to produce surface faulting) are going to be released by National Department of Civil Protection; these would define zonation of areas affected by active and capable faults, with prescriptions for land use planning. As such, the guidelines arise the problem of the time interval and general operational criteria to asses fault capability for the Italian territory. As for the chronology, the review of the international literature and regulatory allowed Galadini et al. (2012) to propose different time intervals depending on the ongoing tectonic regime - compressive or extensional - which encompass the Quaternary. As for the operational criteria, the detailed analysis of the large amount of works dealing with active faulting in Italy shows that investigations exclusively based on surface morphological features (e.g. fault planes exposition) or on indirect investigations (geophysical data), are not sufficient or even unreliable to define the presence of an active and capable fault; instead, more accurate geological information on the Quaternary space-time evolution of the areas affected by such tectonic structures is needed. A test area for which active and capable faults can be first mapped based on such a classical but still effective methodological approach can be the central Apennines. Reference Galadini F., Falcucci E., Galli P., Giaccio B., Gori S., Messina P., Moro M., Saroli M., Scardia G., Sposato A. (2012). Time

  18. Severe Chronic Obstructive Pulmonary Disease : assessment of respiratory muscle activity and the benefits of noninvasive ventilation

    NARCIS (Netherlands)

    Duiverman, Marieke Leontine

    2008-01-01

    This thesis deals with two main topics. First, we investigated respiratory muscle function in Chronic Obstructive Pulmonary Disease (COPD) by surface electromyography. Second, we focused on the benefits of noninvasive ventilation in patients with respiratory failure, both in restrictive pulmonary

  19. Aluminum metal surface cleaning and activation by atmospheric-pressure remote plasma

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, J., E-mail: jmespadero@uco.es; Bravo, J.A.; Calzada, M.D.

    2017-06-15

    Highlights: • Atmospheric-pressure postdischarges have been applied on aluminium surfaces. • The outer hydrocarbon layer is reduced by the action of the postdischarge. • The treatment promotes the appearance of hydrophilic OH radicals in the surface. • Effectivity for distances up to 5 cm allows for treating irregular surfaces. • Ageing in air due to the disappearance of OH radicals has been reported. - Abstract: The use of the remote plasma (postdischarge) of argon and argon-nitrogen microwave plasmas for cleaning and activating the surface of metallic commercial aluminum samples has been studied. The influence of the nitrogen content and the distance between the treated samples and the end of the discharge on the hydrophilicity and the surface energy has been analyzed by means of the sessile drop technique and the Owens-Wendt method. A significant increase in the hydrophilicity has been noted in the treated samples, together with an increase in the surface energy from values around 37 mJ/m{sup 2} to 77 mJ/m{sup 2}. Such increase weakly depends on the nitrogen content of the discharge, and the effectivity of the treatment extends to distances up to 5 cm from the end of the discharge, much longer than those reported in other plasma-based treatments. The analysis of the treated samples using X-ray photoelectron spectroscopy reveals that such increase in the surface energy takes place due to a reduction of the carbon content and an increase in the amount of OH radicals in the surface. These radicals tend to disappear within 24–48 h after the treatment when the samples are stored in contact with ambient air, resulting in the ageing of the treated surface and a partial retrieval of the hydrophobicity of the surface.

  20. Antimicrobial activity of nisin adsorbed to surfaces commonly used in the food industry.

    Science.gov (United States)

    Guerra, Nelson P; Araujo, Ana Belén; Barrera, Ana M; Agrasar, Ana Torrado; Macías, Cristina López; Carballo, Julia; Pastrana, Lorenzo

    2005-05-01

    The adsorption isotherms of nisin to three food contact surfaces, stainless steel, polyethyleneterephthalate (PET), and rubber at 8, 25, 40, and 60 degrees C, were calculated. For all surfaces, the increase in temperature led to a decrease in the affinity between nisin and the surface. The rubber adsorbed a higher amount of nisin (0.697 microg/cm2) in comparison with PET (0.665 microg/cm2) and stainless steel (0.396 microg/cm2). Adsorption of nisin to the stainless steel surface described L-2 type curves for all temperatures assayed. However, for PET and rubber surfaces, the isotherms were L-2 type (at 40 and 60 degrees C) and L-4 type curves (at 8 and 25 degrees C). Nisin retained its antibacterial activity once adsorbed to the food contact surfaces and was able to inhibit the growth of Enterococcus hirae CECT 279 on Rothe agar medium. The attachment of three Listeria monocytogenes strains to the three surfaces was found to be dependent on the surface, the strain, and the initial bacterial suspension in contact with the surface. The adsorption of Nisaplin on surfaces reduced the attachment of all L. monocytogenes strains tested. The effect of PET-based bioactive packaging in food was very encouraging. When applied to a food system, nisin-adsorbed PET bottles reduced significantly (P < 0.05) the levels of the total aerobic plate counts in skim milk by approximately 1.4 log units after 24 days of refrigerated storage (4 degrees C), thus extending its shelf life.

  1. Plasma technological effect of vacuum-arc discharge to surface of constructional materials in the presence of surface-active substances

    International Nuclear Information System (INIS)

    Arustamov, V.N.; Ashurov, Kh.B.; Kadirov, Kh. Kh.; Khudaykulov, I.Kh.

    2013-01-01

    The effect of surface-active agents, KOH, NaOH, Ba(OH)x8H 2 O and Ba(NO 2 ) 2 x2H 2 O on the mechanism of interaction of the vacuum-arc discharge to the steel surface, the specific energy consumption, plasma vacuum-arc steel sample treatment and surface roughness are considered. It is shown that the putting of the alkali solution 20% KOH and NaOH on the treated steel surface leads to the reduction of energy consumption of 1.5-2.4 times and a decrease in the surface roughness of 1.5-3.2 times. (author)

  2. Influence of TiO{sub 2} Surface Properties on Water Pollution Treatment and Photocatalytic Activity

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Min [Southwest Univ. of Science and Technology, Mianyang (China)

    2013-03-15

    The titania surface showed different characteristics depending on the charge of the dye molecules. Compared with the MB molecules, the negatively charged MO molecules strongly adsorbed on the titania surface. Furthermore, the decomposition kinetics of the dye molecules by the photocatalytic activity also deepened with the charge of the dye molecules. The relation between the UV irradiation time and the molar ratio of the decomposed dye molecules followed the Avrami equation. According to the results of the analysis by using the Avrami equation, the MO molecules were decomposed on the titania particle surface. In contrast, the MB molecules were decomposed in the aqueous solution. The difference in kinetics was related to the interaction of the dye molecules and the titania surface. These preferential adsorption and decomposition characteristics will improve its applications in water pollution treatment.

  3. Heavy metals uptake by sonicated activated sludge: Relation with floc surface properties

    International Nuclear Information System (INIS)

    Laurent, Julien; Casellas, Magali; Dagot, Christophe

    2009-01-01

    The effects of sonication of activated sludge on heavy metal uptake were in a first time investigated in respect with potential modifications of floc surface properties. The treatment led to the simultaneous increase of specific surface area and of the availability of negative and/or hydrophilic sites. In parallel, organic matter was released in the soluble fraction. Sorption isotherms of cadmium and copper showed that uptake characteristics and mechanisms were highly dependent on both heavy metal species and specific energy supplied. The increase of both specific surface area and fixation sites availability led to the increase of Cd(II) uptake. For Cu(II), organic matter released in soluble phase during the treatment seemed to act as a ligand and to limit adsorption on flocs surface. Three different heavy metals uptake mechanisms have been identified: proton exchange, ion exchange and (co)precipitation

  4. Biological and surface-active properties of double-chain cationic amino acid-based surfactants.

    Science.gov (United States)

    Greber, Katarzyna E; Dawgul, Małgorzata; Kamysz, Wojciech; Sawicki, Wiesław; Łukasiak, Jerzy

    2014-08-01

    Cationic amino acid-based surfactants were synthesized via solid phase peptide synthesis and terminal acylation of their α and ε positions with saturated fatty acids. Five new lipopeptides, N-α-acyl-N-ε-acyl lysine analogues, were obtained. Minimum inhibitory concentration and minimum bactericidal (fungicidal) concentration were determined on reference strains of bacteria and fungi to evaluate the antimicrobial activity of the lipopeptides. Toxicity to eukaryotic cells was examined via determination of the haemolytic activities. The surface-active properties of these compounds were evaluated by measuring the surface tension and formation of micelles as a function of concentration in aqueous solution. The cationic surfactants demonstrated diverse antibacterial activities dependent on the length of the fatty acid chain. Gram-negative bacteria and fungi showed a higher resistance than Gram-positive bacterial strains. It was found that the haemolytic activities were also chain length-dependent values. The surface-active properties showed a linear correlation between the alkyl chain length and the critical micelle concentration.

  5. Gold Incorporated Mesoporous Silica Thin Film Model Surface as a Robust SERS and Catalytically Active Substrate

    Directory of Open Access Journals (Sweden)

    Anandakumari Chandrasekharan Sunil Sekhar

    2016-05-01

    Full Text Available Ultra-small gold nanoparticles incorporated in mesoporous silica thin films with accessible pore channels perpendicular to the substrate are prepared by a modified sol-gel method. The simple and easy spin coating technique is applied here to make homogeneous thin films. The surface characterization using FESEM shows crack-free films with a perpendicular pore arrangement. The applicability of these thin films as catalysts as well as a robust SERS active substrate for model catalysis study is tested. Compared to bare silica film our gold incorporated silica, GSM-23F gave an enhancement factor of 103 for RhB with a laser source 633 nm. The reduction reaction of p-nitrophenol with sodium borohydride from our thin films shows a decrease in peak intensity corresponding to –NO2 group as time proceeds, confirming the catalytic activity. Such model surfaces can potentially bridge the material gap between a real catalytic system and surface science studies.

  6. Activation and adsorption of CO{sub 2} on copper surfaces and clusters

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, Seema; Dharmvir, Keya, E-mail: keya@pu.ac.in [Department of Physics, Center of Advanced Studies, Panjab University, Chandigarh- 160014 (India); Goel, Neetu [Department of Chemistry, Center of Advanced Studies, Panjab University, Chandigarh-160014 (India)

    2014-04-24

    The activation and adsorption of CO{sub 2} over Cu{sub n} clusters have been investigated by first principle calculations. Results of these calculations are compared with the previous studies of adsorption of CO{sub 2} on Cu (hkl) surfaces [Wang et al. Surface Science 570 (2004) 205–217]. We find that CO{sub 2} is preferentially adsorbed over the clusters in comparison with Cu (hkl) surfaces. The Cu13 cluster in particular dissociates the CO{sub 2} molecule adsorbed on the one of the caps of the icosahedron into CO and atomic oxygen. This activated configuration can act as a precursor to reactions leading to hydrocarbon fuels from CO{sub 2}.

  7. Nanometer scale titanium surface texturing are detected by signaling pathways involving transient FAK and Src activations.

    Directory of Open Access Journals (Sweden)

    Willian F Zambuzzi

    Full Text Available It is known that physico/chemical alterations on biomaterial surfaces have the capability to modulate cellular behavior, affecting early tissue repair. Such surface modifications are aimed to improve early healing response and, clinically, offer the possibility to shorten the time from implant placement to functional loading. Since FAK and Src are intracellular proteins able to predict the quality of osteoblast adhesion, this study evaluated the osteoblast behavior in response to nanometer scale titanium surface texturing by monitoring FAK and Src phosphorylations.Four engineered titanium surfaces were used for the study: machined (M, dual acid-etched (DAA, resorbable media microblasted and acid-etched (MBAA, and acid-etch microblasted (AAMB. Surfaces were characterized by scanning electron microscopy, interferometry, atomic force microscopy, x-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. Thereafter, those 4 samples were used to evaluate their cytotoxicity and interference on FAK and Src phosphorylations. Both Src and FAK were investigated by using specific antibody against specific phosphorylation sites.The results showed that both FAK and Src activations were differently modulated as a function of titanium surfaces physico/chemical configuration and protein adsorption.It can be suggested that signaling pathways involving both FAK and Src could provide biomarkers to predict osteoblast adhesion onto different surfaces.

  8. IDENTIFYING RECENT SURFACE MINING ACTIVITIES USING A NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI) CHANGE DETECTION METHOD

    Science.gov (United States)

    Coal mining is a major resource extraction activity on the Appalachian Mountains. The increased size and frequency of a specific type of surface mining, known as mountain top removal-valley fill, has in recent years raised various environmental concerns. During mountainto...

  9. Surface rupturing earthquakes repeated in the 300 years along the ISTL active fault system, central Japan

    Science.gov (United States)

    Katsube, Aya; Kondo, Hisao; Kurosawa, Hideki

    2017-06-01

    Surface rupturing earthquakes produced by intraplate active faults generally have long recurrence intervals of a few thousands to tens of thousands of years. We here report the first evidence for an extremely short recurrence interval of 300 years for surface rupturing earthquakes on an intraplate system in Japan. The Kamishiro fault of the Itoigawa-Shizuoka Tectonic Line (ISTL) active fault system generated a Mw 6.2 earthquake in 2014. A paleoseismic trench excavation across the 2014 surface rupture showed the evidence for the 2014 event and two prior paleoearthquakes. The slip of the penultimate earthquake was similar to that of 2014 earthquake, and its timing was constrained to be after A.D. 1645. Judging from the timing, the damaged area, and the amount of slip, the penultimate earthquake most probably corresponds to a historical earthquake in A.D. 1714. The recurrence interval of the two most recent earthquakes is thus extremely short compared with intervals on other active faults known globally. Furthermore, the slip repetition during the last three earthquakes is in accordance with the time-predictable recurrence model rather than the characteristic earthquake model. In addition, the spatial extent of the 2014 surface rupture accords with the distribution of a serpentinite block, suggesting that the relatively low coefficient of friction may account for the unusually frequent earthquakes. These findings would affect long-term forecast of earthquake probability and seismic hazard assessment on active faults.

  10. Probing the Active Surface Sites for CO Reduction on Oxide-Derived Copper Electrocatalysts

    DEFF Research Database (Denmark)

    Verdaguer Casadevall, Arnau; Li, Christina W.; Johansson, Tobias Peter

    2015-01-01

    CO electroreduction activity on oxide-derived Cu (OD-Cu) was found to correlate with metastable surface features that bind CO strongly. OD-Cu electrodes prepared by H-2 reduction of Cu2O precursors reduce CO to acetate and ethanol with nearly 50% Faradaic efficiency at moderate overpotential. Tem...

  11. Neutron activation analysis to the profile surface sediments from several sites on the Havana Bay

    International Nuclear Information System (INIS)

    Diaz Riso, O.; Gelen, A.; Lopez, N.; Gonzalez, H.; Manso, M.V.; Graciano, A.M.; Nogueira, C.A.; Beltran, J.; Soto, J.

    2003-01-01

    Instrumental neutron activation analysis (INAA) technique was employed to analyze the surface sediments from several sites on the Havana Bay, Cuba. Measurements of heavy and trace elements in the sediments are reported. The results show that the concentration of the elements is site dependent. The data suggest that an anthropogenic input into the bay from domestic sewage and industries occurred

  12. Simultaneous interaction of bacteria and tissue cells with photocatalytically activated, anodized titanium surfaces

    NARCIS (Netherlands)

    Yue, Chongxia; Kuijer, Roelof; Kaper, H. J.; van der Mei, Henderina; Busscher, Hendrik; Kuijer, Roelof

    Photocatalytic-activation of anodized TiO2-surfaces has been demonstrated to yield antibacterial and tissue integrating effects, but effects on simultaneous growth of tissue cells and bacteria in co-culture have never been studied. Moreover, it is unknown how human-bone-marrow-mesenchymal-stem

  13. Preferences for Deep-Surface Learning: A Vocational Education Case Study Using a Multimedia Assessment Activity

    Science.gov (United States)

    Hamm, Simon; Robertson, Ian

    2010-01-01

    This research tests the proposition that the integration of a multimedia assessment activity into a Diploma of Events Management program promotes a deep learning approach. Firstly, learners' preferences for deep or surface learning were evaluated using the revised two-factor Study Process Questionnaire. Secondly, after completion of an assessment…

  14. Minimum activation martensitic alloys for surface disposal after exposure to neutron flux

    Science.gov (United States)

    Lechtenberg, Thomas

    1985-01-01

    Steel alloys for long-term exposure to neutron flux have a martensitic microstructure and contain chromium, carbon, tungsten, vanadium and preferably titanium. Activation of the steel is held to within acceptable limits for eventual surface disposal by stringently controlling the impurity levels of Ni, Mo, Cu, N, Co, Nb, Al and Mn.

  15. Visualization of the distribution of surface-active block copolymers in PDMS-based coatings

    DEFF Research Database (Denmark)

    Noguer, A. Camós; Latipov, R.; Madsen, F. B.

    2018-01-01

    and added to a PDMS coating for visualization purposes. The surface-activity and biofouling resistance of the synthesized copolymer was confirmed by water contact angle measurements and seawater immersion experiments. Confocal laser scanning microscopy (CLSM) images showed that the triblock copolymer...

  16. Effect of surface-active substance on nasal mucociliary clearance time

    DEFF Research Database (Denmark)

    Outzen, K E; Svane-Knudsen, V

    1993-01-01

    Mucociliary clearance measured by saccharin clearance time is depending on ciliary function and on the physiological characteristics of mucus. The aim of this study was to determine whether the application of surface-active substances changed the mucociliary transport time. Twenty healthy persons...

  17. SUSTAINED HYPERLIPEMIA INDUCED IN RABBITS BY MEANS OF INTRAVENOUSLY INJECTED SURFACE-ACTIVE AGENTS

    Science.gov (United States)

    Kellner, Aaron; Correll, James W.; Ladd, Anthony T.

    1951-01-01

    The intravenous injection of the surface-active agents Tween 80 and Triton A20 into rabbits fed a normal diet resulted in marked and sustained elevations of the cholesterol, phospholipid, and total lipid content of their blood. The increase in phospholipid in general paralleled that of the blood cholesterol. The implications of the findings are briefly discussed. PMID:14824409

  18. THE SIZE AND SURFACE COATING OF NANOSILVER DIFFERENTIALLY AFFECTS BIOLOGICAL ACTIVITY IN BLOOD BRAIN BARRIER (RBEC4) CELLS.

    Science.gov (United States)

    Linking the physical properties of nanoparticles with differences in their biological activity is critical for understanding their potential toxicity and mode of action. The influence of aggregate size, surface coating, and surface charge on nanosilver's (nanoAg) movement through...

  19. Contact activation of blood coagulation on a defined kaolin/collagen surface in a microfluidic assay.

    Science.gov (United States)

    Zhu, Shu; Diamond, Scott L

    2014-12-01

    Generation of active Factor XII (FXIIa) triggers blood clotting on artificial surfaces and may also enhance intravascular thrombosis. We developed a patterned kaolin (0 to 0.3 pg/μm(2))/type 1 collagen fibril surface for controlled microfluidic clotting assays. Perfusion of whole blood (treated only with a low level of 4 μg/mL of the XIIa inhibitor, corn trypsin inhibitor) drove platelet deposition followed by fibrin formation. At venous wall shear rate (100 s(-1)), kaolin accelerated onset of fibrin formation by ~100 sec when compared to collagen alone (250 sec vs. 350 sec), with little effect on platelet deposition. Even with kaolin present, arterial wall shear rate (1000 s(-1)) delayed and suppressed fibrin formation compared to venous wall shear rate. A comparison of surfaces for extrinsic activation (tissue factor TF/collagen) versus contact activation (kaolin/collagen) that each generated equal platelet deposition at 100 s(-1) revealed: (1) TF surfaces promoted much faster fibrin onset (at 100 sec) and more endpoint fibrin at 600 sec at either 100 s(-1) or 1000 s(-1), and (2) kaolin and TF surfaces had a similar sensitivity for reduced fibrin deposition at 1000 s(-1) (compared to fibrin formed at 100 s(-1)) despite differing coagulation triggers. Anti-platelet drugs inhibiting P2Y1, P2Y12, cyclooxygenase-1 or activating IP-receptor or guanylate cyclase reduced platelet and fibrin deposition on kaolin/collagen. Since FXIIa or FXIa inhibition may offer safe antithrombotic therapy, especially for biomaterial thrombosis, these defined collagen/kaolin surfaces may prove useful in drug screening tests or in clinical diagnostic assays of blood under flow conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Covalent-display of an active chimeric-recombinant tissue plasminogen activator on polyhydroxybutyrate granules surface.

    Science.gov (United States)

    Hafizi, Akram; Malboobi, Mohamad Ali; Jalali-Javaran, Mokhtar; Maliga, Pal; Alizadeh, Houshang

    2017-11-01

    To develop a deliberately engineered expression and purification system for an active chimeric-recombinant tissue plasminogen activator (crtPA) using co-expression with polyhydroxybutyrate (PHB) operon genes. Fusion of crtPA with PhaC-synthase simplified the purification steps through crtPA sedimentation with PHB particles. Moreover, the covalently immobilized crtPA was biologically active as shown in a chromogenic assay. Upon WELQut-protease activity, the released single-chain crtPA converted to the two-chain form which produced a pattern of bands with approx. MW of 32 and 11 kDa in addition to the full length crtPA. Fusion of crtPA with PhaC-synthase not only simplifies purification from the bacterial host lysate, but also co-expression of PHB operon genes creates an oxidative environment, thereby reducing the inclusion body formation possibility. The isolated crtPA-PHB granules exhibited crtPA serine protease activity. Thus, fusion with the PhaC protein could be used as a scaffold for covalent displaying of functional disulfide-rich proteins.

  1. Role of nanostructured gold surfaces on monocyte activation and Staphylococcus epidermidis biofilm formation

    Directory of Open Access Journals (Sweden)

    Svensson S

    2014-02-01

    Full Text Available Sara Svensson,1,2 Magnus Forsberg,1,2 Mats Hulander,1,2 Forugh Vazirisani,1,2 Anders Palmquist,1,2 Jukka Lausmaa,2,3 Peter Thomsen,1,2 Margarita Trobos1,21Department of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; 2BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden; 3SP Technical Research Institute of Sweden, Borås, SwedenAbstract: The role of material surface properties in the direct interaction with bacteria and the indirect route via host defense cells is not fully understood. Recently, it was suggested that nanostructured implant surfaces possess antimicrobial properties. In the current study, the adhesion and biofilm formation of Staphylococcus epidermidis and human monocyte adhesion and activation were studied separately and in coculture in different in vitro models using smooth gold and well-defined nanostructured gold surfaces. Two polystyrene surfaces were used as controls in the monocyte experiments. Fluorescent viability staining demonstrated a reduction in the viability of S. epidermidis close to the nanostructured gold surface, whereas the smooth gold correlated with more live biofilm. The results were supported by scanning electron microscopy observations, showing higher biofilm tower formations and more mature biofilms on smooth gold compared with nanostructured gold. Unstimulated monocytes on the different substrates demonstrated low activation, reduced gene expression of pro- and anti-inflammatory cytokines, and low cytokine secretion. In contrast, stimulation with opsonized zymosan or opsonized live S. epidermidis for 1 hour significantly increased the production of reactive oxygen species, the gene expression of tumor necrosis factor-α (TNF-α, interleukin-1β (IL-1β, IL-6, and IL-10, as well as the secretion of TNF-α, demonstrating the ability of the cells to elicit a response and actively phagocytose prey. In addition, cells cultured on the smooth

  2. Anti-fatigue mats, low back pain, and electromyography: An interventional study.

    Science.gov (United States)

    Aghazadeh, Javad; Ghaderi, Mahmoud; Azghani, Mahmood-Reza; Khalkhali, Hamid-Reza; Allahyari, Teimour; Mohebbi, Iraj

    2015-01-01

    Increasing bilateral gluteus medius co-activation has been identified as one of the most important factors in developing low back pain due to prolonged standing in healthy people. This study aims to investigate the impact of an anti-fatigue mat on the bilateral gluteus medius co-activation pattern and to report the low back pain subjectively in 2 different standing positions on the normal rigid surface and on the anti-fatigue mat. While carrying out an easy simulated profession, 16 participants who had no low back pain background were requested to stand for 2 h in each position, with and without using the anti-fatigue floor mat, respectively. At the beginning of standing process and at every 15 min until the time of 120 min lapses, electric activities for the bilateral gluteus medius co-activation and subjective pain level in low back area were collected by the surface electromyogeraphy (EMG) and the visual analogue scale (VAS), respectively in each position. The obtained findings revealed that the anti-fatigue mat significantly decreased subjective pain level in low back area among 15 participants (p 0.05). The findings obtained under this study related to the impact of the anti-fatigue mat upon the low back pain based on the increase of > 10 mm on the VAS threshold, which showed that this intervention had no significant impact upon decreasing the number of patients suffering from the low back pain and also minimizing the bilateral gluteus medius co-activation in both pain developer groups (p > 0.05). However, 73% of the participants preferred to apply it. It seems that the anti-fatigue mat may be useful in reducing the low back pain although it objectively didn't significantly change the gluteus medius co-activation pattern related to the low back pain. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  3. Anti-fatigue mats, low back pain, and electromyography: An interventional study

    Directory of Open Access Journals (Sweden)

    Javad Aghazadeh

    2015-04-01

    Full Text Available Objectives: Increasing bilateral gluteus medius co-activation has been identified as one of the most important factors in developing low back pain due to prolonged standing in healthy people. This study aims to investigate the impact of an anti-fatigue mat on the bilateral gluteus medius co-activation pattern and to report the low back pain subjectively in 2 different standing positions on the normal rigid surface and on the anti-fatigue mat. Material and Methods: While carrying out an easy simulated profession, 16 participants who had no low back pain background were requested to stand for 2 h in each position, with and without using the anti-fatigue floor mat, respectively. At the beginning of standing process and at every 15 min until the time of 120 min lapses, electric activities for the bilateral gluteus medius co-activation and subjective pain level in low back area were collected by the surface electromyogeraphy (EMG and the visual analogue scale (VAS, respectively in each position. Results: The obtained findings revealed that the anti-fatigue mat significantly decreased subjective pain level in low back area among 15 participants (p 0.05. The findings obtained under this study related to the impact of the anti-fatigue mat upon the low back pain based on the increase of > 10 mm on the VAS threshold, which showed that this intervention had no significant impact upon decreasing the number of patients suffering from the low back pain and also minimizing the bilateral gluteus medius co-activation in both pain developer groups (p > 0.05. However, 73% of the participants preferred to apply it. Conclusions: It seems that the anti-fatigue mat may be useful in reducing the low back pain although it objectively didn’t significantly change the gluteus medius co-activation pattern related to the low back pain.

  4. Pure and Oxidized Copper Materials as Potential Antimicrobial Surfaces for Spaceflight Activities

    Science.gov (United States)

    Hahn, C.; Hans, M.; Hein, C.; Mancinelli, R. L.; Mücklich, F.; Wirth, R.; Rettberg, P.; Hellweg, C. E.; Moeller, R.

    2017-12-01

    Microbial biofilms can lead to persistent infections and degrade a variety of materials, and they are notorious for their persistence and resistance to eradication. During long-duration space missions, microbial biofilms present a danger to crew health and spacecraft integrity. The use of antimicrobial surfaces provides an alternative strategy for inhibiting microbial growth and biofilm formation to conventional cleaning procedures and the use of disinfectants. Antimicrobial surfaces contain organic or inorganic compounds, such as antimicrobial peptides or copper and silver, that inhibit microbial growth. The efficacy of wetted oxidized copper layers and pure copper surfaces as antimicrobial agents was tested by applying cultures of Escherichia coli and Staphylococcus cohnii to these metallic surfaces. Stainless steel surfaces were used as non-inhibitory control surfaces. The production of reactive oxygen species and membrane damage increased rapidly within 1 h of exposure on pure copper surfaces, but the effect on cell survival was negligible even after 2 h of exposure. However, longer exposure times of up to 4 h led to a rapid decrease in cell survival, whereby the survival of cells was additionally dependent on the exposed cell density. Finally, the release of metal ions was determined to identify a possible correlation between copper ions in suspension and cell survival. These measurements indicated a steady increase of free copper ions, which were released indirectly by cells presumably through excreted complexing agents. These data indicate that the application of antimicrobial surfaces in spaceflight facilities could improve crew health and mitigate material damage caused by microbial contamination and biofilm formation. Furthermore, the results of this study indicate that cuprous oxide layers were superior to pure copper surfaces related to the antimicrobial effect and that cell density is a significant factor that influences the time dependence of

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

    DEFF Research Database (Denmark)

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

    1997-01-01

    In order to use the volitional electromyography (EMG) as a control signal for the stimulation of the same muscle, it is necessary to eliminate the stimulation artifacts and the muscle responses caused by the stimulation. The stimulation artifacts, caused by the electric field in skin and tissue....... For variations in shape of the muscle responses and for real data, an increased filter performance can be achieved by increasing the filter length. Using a filter length of up to seven stimulation periods, it is possible to reduce real muscle responses to a level comparable with the background noise. Using...... the shut-down circuit and the adaptive filter both the stimulation artifacts and the muscle responses can be effectively eliminated from the EMG signal from a stimulated muscle. It is therefore possible to extract the volitional EMG from a partly paralyzed muscle and use it for controlling the stimulation...

  6. Precursor type affecting surface properties and catalytic activity of sulfated zirconia

    Directo