- Brisbane, Queensland, Australia
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2002-2003 > Academic research: refereed > Refereed conference pape
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ABSTRACT The major purpose of this study was to compare the effects of oscillating and static isometric tasks on thigh muscle activation patterns. Many articles report knee torques in flexion and extension but very few report medial and... more
ABSTRACT The major purpose of this study was to compare the effects of oscillating and static isometric tasks on thigh muscle activation patterns. Many articles report knee torques in flexion and extension but very few report medial and lateral rotation torques, with even fewer reporting combinations of flexion/extension and medial/lateral rotation. A specially designed ‘Geniculandum’ with a fixed, instrumented ski boot was used to calculate static knee torques in 3 independent planes of motion. Eight female subjects performed 15 isometric experimental tasks in the seated position with a knee angle of 90°. There were 9 static tasks and 6 oscillating (0.5 Hz) torque productions at 50% of maximum voluntary contraction (MVC). The tasks included single and dual degrees of freedom. Myoelectric activities of 6 muscles acting across the knee (vastus medialis – VM, vastus lateralis – VL, rectus femoris – RF, semitendinosus/semimembranosus – ST/SM, biceps femoris – BF and tensor fasciae latae – TFL) were recorded using surface electromyography. MVCs were 157 ± 47 Nm for knee extension, 84 ± 35 Nm for flexion, 11 ± 3 Nm for lateral rotation, and 8 ± 1 Nm for medial rotation. Compared with slow isokinetic strengths of the nonsurgical knee of male tendon transfer patients (Osternig et al. Arch.Phys. Medical Rehab. 62, 1981), the female subjects had strengths that were 97% (flexion), 63% (extension), 24% (lateral rotation) and 21% (medial rotation). The relatively weak knee rotatory muscles could be a factor that contributes to the high incidence of noncontact knee ligament injuries in female sports. At 50% MVC, the muscles that were most active during single degree of freedom tasks were VM (ext. 40% Max EMG), VL (ext. 45% Max EMG) and BF (flex. 55% Max EMG), while others were most active during dual degree of freedom tasks; RF (ext. + lat. rot. 55% Max EMG), ST/SM (flex. + med. rot. 70% Max EMG) and TFL (ext. + lat. rot. 30% Max EMG). Generally, levels of muscle activation increased when isolated flexion-extension oscillating tasks were performed, in comparison to the static isometric tasks. However, activity levels tended to decrease during oscillating 2-degree of freedom tasks, such as oscillating lateral/ medial rotation with a constant extension or flexion torque.
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Abnormal patterns of trunk muscle activity could affect the biomechanics of spinal movements and result in back pain. The present study aimed to examine electromyographic (EMG) activity of abdominal and back muscles as well as triaxial... more
Abnormal patterns of trunk muscle activity could affect the biomechanics of spinal movements and result in back pain. The present study aimed to examine electromyographic (EMG) activity of abdominal and back muscles as well as triaxial torque output during isometric axial rotation at different exertion levels in back pain patients and matched controls. Twelve back pain patients and 12 matched controls performed isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions in a standing position. Surface EMG activity of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus were recorded bilaterally. The primary torque in the transverse plane and the coupling torques in sagittal and coronal planes were measured. Results showed that there was a trend (P = 0.08) of higher flexion coupling torque during left axial rotation exertion in back pain patients. Higher activity for external oblique and lower activity for multifidus was shown during left axial rotation exertion in back pain group when compared to the control group. In right axial rotation, back pain patients exhibited lesser activity of rectus abdominis at higher levels of exertion when compared with matched controls. These findings demonstrated that decreased activation of one muscle may be compensated by overactivity in other muscles. The reduced levels of activity of the multifidus muscle during axial rotation exertion in back pain patients may indicate that spinal stability could be compromised. Future studies should consider these alternations in recruitment patterns in terms of spinal stability and internal loading. The findings also indicate the importance of training for coordination besides the strengthening of trunk muscles during rehabilitation process.
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Electromyographic (EMG) studies have shown that a large number of trunk muscles are recruited during axial rotation. The functional roles of these trunk muscles in axial rotation are multiple and have not been well investigated. In... more
Electromyographic (EMG) studies have shown that a large number of trunk muscles are recruited during axial rotation. The functional roles of these trunk muscles in axial rotation are multiple and have not been well investigated. In addition, there is no information on the coupling torque at different exertion levels during axial rotation. The aim of the study was to investigate the functional roles of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus during isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions (MVC) in a standing position. The coupling torques in sagittal and coronal planes were measured during axial rotation to examine the coupling nature of torque at different levels of exertions. Results showed that the coupled sagittal torque switches from nil to flexion at maximum exertion of axial rotation. Generally, higher EMG activities were shown at higher exertion levels for all the trunk muscles. Significant differences in activity between the right and left axial rotation exertions were demonstrated in external oblique, internal oblique, latissimus dorsi and iliocostalis lumborum while no difference was shown in rectus abdominis and multifidus. These results demonstrated the different functional roles of trunk muscles during axial rotation. This is important considering that the abdominal and back muscles not only produce torque but also maintain the spinal posture and stability during axial rotation exertions. The changing coupling torque direction in the sagittal plane when submaximal to maximal exertions were compared may indicate the complex nature of the kinetic coupling of trunk muscles.
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Back muscles are important to the stability of the lumbar spine. Muscle fiber composition may give some indication of the functional capacity of these muscles. This review explores the relationship between muscle fiber composition and... more
Back muscles are important to the stability of the lumbar spine. Muscle fiber composition may give some indication of the functional capacity of these muscles. This review explores the relationship between muscle fiber composition and functional capacity of back muscles. The reference values for the type and size of the muscle fibers found in the back musculature of healthy subjects and patients with back pain are also presented. A high percentage of type I fibers, which are larger in size than type II fibers, has been found in back muscles at the thoracic and lumbar levels. This is in accordance with the postural function of these muscles. The diameter of type II fibers is smaller in females than males, which may partly explain the lesser strength and greater endurance capacity of back muscles in females. Due to the limited amount of pertinent data, no conclusive evidence is available regarding age-related changes in muscle fiber composition in the musculature of the back. In patients with lumbar disorders, pathological changes and selective atrophy of type II fibers are seen, and these can be changed with adequate exercises. Further research is suggested to address issues related to gender, age, back pain, and exercise and their effects on the apparent back muscle fiber composition.
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Changes in spinal posture between the erect and flexed positions were calculated using angular measurements from lateral photographs and radiographs of ten adult male subjects. For photographic measurements, the thoracolumbar vertebral... more
Changes in spinal posture between the erect and flexed positions were calculated using angular measurements from lateral photographs and radiographs of ten adult male subjects. For photographic measurements, the thoracolumbar vertebral column was modelled as either a single segment or as three segments. In the three-segment model, there was a non-significant correlation between the decrease in lumbar concavity and intervertebral motion. In addition, there was a non-significant negative correlation between the increase in thoracic convexity and lumbar motion determined radiographically. In the single-segment model, the decrease in angulation between the thoracolumbar spine and pelvis was a good representation of lumbar spine flexion as determined by the mean lumbar intervertebral angular change. Therefore, modelling the thoracolumbar vertebral column as a single segment allowed better estimation of lumbar intervertebral angular change during flexion than a three-segment model. The results indicate that large range dynamic motion of the lumbar vertebral column can be represented using photographic analysis of the positions of three easily identified anatomical landmarks: the anterior superior iliac spine, posterior superior iliac spine and the spinous process of the first thoracic vertebra.
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... Available online 8 September 1998. Abstract. In this study we examined momentarms of the complete muscle system of the elbow, including the wrist flexors that have their proximal attachment point on the humerus. This study ...
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The pattern of movement self-selected by 39 subjects to lift light loads from 9 cm above the ground is described in kinematic and electromyographic terms. Hamstring length changes were estimated from hip and knee angular kinematics.... more
The pattern of movement self-selected by 39 subjects to lift light loads from 9 cm above the ground is described in kinematic and electromyographic terms. Hamstring length changes were estimated from hip and knee angular kinematics. Subjects adopted a posture at the start of the lift intermediate between stoop and full-squat postures. A consistent coordination between knee, hip, and lumbar vertebral joints during lifting was described through calculation of the relative phase between adjacent joints and found to be exaggerated with increases in load mass. During the early phase of lifting, knee extension leads hip extension, which in turn leads extension of the lumbar vertebral joints. Early in the lifting movement, when load acceleration is greatest, the erectores spinae are thus relatively long and shortening slowly. Both of these factors produce greater back extensor strength. Rapid hamstring shortening is also delayed, which enhances their strength, and coactivation of the monoa...
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ABSTRACT
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The aim of the present study was to investigate the between-days reliability of electromyographic (EMG) measurement of 6 bilateral trunk muscles and also the torque output in 3 planes during isometric right and left axial rotation at... more
The aim of the present study was to investigate the between-days reliability of electromyographic (EMG) measurement of 6 bilateral trunk muscles and also the torque output in 3 planes during isometric right and left axial rotation at different exertion levels. Ten healthy subjects performed isometric right and left axial rotation at 100, 70, 50 and 30% maximum voluntary contractions in two testing sessions at least 7 days apart. EMG amplitude and frequency analyses of the recorded surface EMG signals were performed for rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus bilaterally. The primary torque in the transverse plane and the coupling torques in sagittal and coronal planes were measured. For both EMG amplitude and frequency values, good (intraclass correlation coefficient, ICC=0.75-0.89) to excellent (ICC>/=0.90) reliability was found in the 6 trunk muscles at different exertion levels during axial rotation. The reliability of both maximal isometric axial rotation torque and coupling torques in sagittal and coronal planes were found to be excellent (ICC>/=0.93). Good to excellent reliability of EMG measures of trunk muscles and torque measurements during isometric axial rotation was demonstrated. This provides further confidence of using EMG and triaxial torque assessment as outcome measures in rehabilitation and in the evaluation of the human performance in the work place.
Research Interests: Engineering, Electrophysiology, Motor Control, Humans, Male, and 15 moreHuman Performance, Abdominal Muscles, Electromyography, Clinical Neurophysiology, Intraclass Correlation Coefficient, Adult, Back, Conduction Velocity, Healthy Subjects, Neurosciences, Isometric Contraction, Maximum Voluntary Contraction, Outcome measure, Psychology and Cognitive Sciences, and Medical and Health Sciences
Abstract In small groups, medical students were involved in generating questions to contribute to an online item bank. This study sought to support collaborative question‐writing and enhance students' metacognitive abilities, in... more
Abstract In small groups, medical students were involved in generating questions to contribute to an online item bank. This study sought to support collaborative question‐writing and enhance students' metacognitive abilities, in particular, their ability to self‐regulate ...
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Research Interests: Skeletal muscle biology, Humans, Back Pain, Male, Abdominal Muscles, and 15 moreElectromyography, Coefficient of Variation, Risk factors, Clinical Sciences, Adult, Public health systems and services research, Time Factors, Muscle Fatigue, Risk Factors, Rotation, Parameters, Reference Values, Isometric Contraction, Maximum Voluntary Contraction, and photic stimulation
Electromyographic (EMG) studies have shown that a large number of trunk muscles are recruited during axial rotation. The functional roles of these trunk muscles in axial rotation are multiple and have not been well investigated. In... more
Electromyographic (EMG) studies have shown that a large number of trunk muscles are recruited during axial rotation. The functional roles of these trunk muscles in axial rotation are multiple and have not been well investigated. In addition, there is no information on the coupling torque at different exertion levels during axial rotation. The aim of the study was to investigate the functional roles of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus during isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions (MVC) in a standing position. The coupling torques in sagittal and coronal planes were measured during axial rotation to examine the coupling nature of torque at different levels of exertions. Results showed that the coupled sagittal torque switches from nil to flexion at maximum exertion of axial rotation. Generally, higher EMG activities were shown at higher exertion levels for all the trunk muscles. Significant differences in activity between the right and left axial rotation exertions were demonstrated in external oblique, internal oblique, latissimus dorsi and iliocostalis lumborum while no difference was shown in rectus abdominis and multifidus. These results demonstrated the different functional roles of trunk muscles during axial rotation. This is important considering that the abdominal and back muscles not only produce torque but also maintain the spinal posture and stability during axial rotation exertions. The changing coupling torque direction in the sagittal plane when submaximal to maximal exertions were compared may indicate the complex nature of the kinetic coupling of trunk muscles.
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Repeated measures for intratester reliability were performed. To investigate the intratester reliability of a new measurement technique that evaluates lumbar range of motion in three planes using a pelvic restraint device, and to examine... more
Repeated measures for intratester reliability were performed. To investigate the intratester reliability of a new measurement technique that evaluates lumbar range of motion in three planes using a pelvic restraint device, and to examine the reliability of lumbar lordosis measurement by inclinometer technique. Preliminary normative data on lumbar range of motion and lumbar lordosis were collected for comparison with the findings of previous studies. Various noninvasive measurement methods have been developed for recording lumbar range of motion. However, pelvic movement was not effectively restricted during the use of these measurement techniques. The use of the pelvic restraint device to measure lumbar range of motion has not been investigated previously. Very few studies have investigated the reliability of quantifying lumbar lordosis by the inclinometer technique. Normative values were measured in 35 healthy men, and 12 of these subjects were included for the reliability study. Pelvic motion was limited by the pelvic restraint device during lumbar range of motion measurement in standing. An inclinometer was used for evaluation of lumbar flexion, extension, lateral flexion, and lumbar lordosis, whereas a lumbar rotameter was used to measure axial rotation. Good intratester reliability was shown in the lumbar range of motion and lordosis measurement. Most of the intraclass correlation coefficient and Pearson's r values (accompanied with nonsignificant paired t tests) were greater than 0.9, and most of the intrasubject coefficients of variation were less than 10%. The values of lumbar range of motion in three planes and lumbar lordosis found in the current study were comparable with those from most of the previous studies on these measurements in the normal population. Inclinometer and lumbar rotameter measurements with the use of a pelvic restraint device are reliable for measuring lumbar spine range of motion. Use of the inclinometer technique to record lumbar lordosis also is a reliable measure.
Research Interests: Biomedical Engineering, Methodology, Instrumentation, Lumbar spine, Humans, and 15 moreMeasurement, Male, Deformation, Clinical Sciences, Pelvis, Observer Variation, Adult, Analysis of Variance, Reproducibility of Results, Rotation, Physical Restraint, Range of Motion, Etalon, lumbar vertebrae, and Pliability
Abnormal patterns of trunk muscle activity could affect the biomechanics of spinal movements and result in back pain. The present study aimed to examine electromyographic (EMG) activity of abdominal and back muscles as well as triaxial... more
Abnormal patterns of trunk muscle activity could affect the biomechanics of spinal movements and result in back pain. The present study aimed to examine electromyographic (EMG) activity of abdominal and back muscles as well as triaxial torque output during isometric axial rotation at different exertion levels in back pain patients and matched controls. Twelve back pain patients and 12 matched controls performed isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions in a standing position. Surface EMG activity of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus were recorded bilaterally. The primary torque in the transverse plane and the coupling torques in sagittal and coronal planes were measured. Results showed that there was a trend (P = 0.08) of higher flexion coupling torque during left axial rotation exertion in back pain patients. Higher activity for external oblique and lower activity for multifidus was shown during left axial rotation exertion in back pain group when compared to the control group. In right axial rotation, back pain patients exhibited lesser activity of rectus abdominis at higher levels of exertion when compared with matched controls. These findings demonstrated that decreased activation of one muscle may be compensated by overactivity in other muscles. The reduced levels of activity of the multifidus muscle during axial rotation exertion in back pain patients may indicate that spinal stability could be compromised. Future studies should consider these alternations in recruitment patterns in terms of spinal stability and internal loading. The findings also indicate the importance of training for coordination besides the strengthening of trunk muscles during rehabilitation process.
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A cross-sectional case-control study. To examine the effect of fatigue on torque output as well as electromyographic frequency and amplitude values of trunk muscles during isometric axial rotation exertion in back pain patients and to... more
A cross-sectional case-control study. To examine the effect of fatigue on torque output as well as electromyographic frequency and amplitude values of trunk muscles during isometric axial rotation exertion in back pain patients and to compare the results with a matched control group. Back pain patients exhibited different activation strategies in trunk muscles during the axial rotation exertions. Fatigue changes of abdominal and back muscles during axial rotation exertion have not been examined in patients with back pain. Twelve back pain patients and 12 matched controls performed isometric fatiguing axial rotation to both sides at 80% maximum voluntary contraction in a standing position. During the fatiguing exertion, electromyographic changes of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum, and multifidus were recorded bilaterally. The primary torque in the transverse plane and the coupling torques in sagittal and coronal planes were also measured. No difference in the endurance capacity was found between back pain and control groups. At the initial period of the exertion, back pain patients demonstrated a statistical trend (P = 0.058) of greater sagittal coupling torque as well as lower activity of rectus abdominis and multifidus and higher activity in external oblique. During the fatigue process similar changes of coupling torque were demonstrated in both sagittal and coronal planes, but a smaller fatigue rate for right external oblique, increase in median frequency for latissimus dorsi, and lesser increase in activity for back muscles were found in the back pain group compared with the control group. Alterations in electromyographic activation and fatigue rates of abdominal and back muscles demonstrated during the fatigue process provide insights into the muscle dysfunctions in back pain and may help clinicians to devise more rational treatment strategies.
Research Interests: Biomedical Engineering, Risk, Performance, Fourier Analysis, Humans, and 15 moreBack Pain, Male, Orthopedics, Reliability, Electromyography, Body Mass Index, Clinical Sciences, Adult, Muscle Fatigue, Cross Sectional Studies, Abdomen, Case Control Studies, Isometric Contraction, Physical Endurance, and physical exertion
In small groups, medical students were involved in generating questions to contribute to an online item bank. This study sought to support collaborative question‐writing and enhance students' metacognitive abilities, in particular,... more
In small groups, medical students were involved in generating questions to contribute to an online item bank. This study sought to support collaborative question‐writing and enhance students' metacognitive abilities, in particular, their ability to self‐regulate ...
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Manual lifting is consistently linked with a high incidence of occupational injuries (eg, Jensen, 1988). It seems reasonable to suggest that the damaging physical effects of lifting might be partly a function of the postures adopted... more
Manual lifting is consistently linked with a high incidence of occupational injuries (eg, Jensen, 1988). It seems reasonable to suggest that the damaging physical effects of lifting might be partly a function of the postures adopted throughout the lifting movement and the ...
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This experiment investigated the effects of varying bench inclination and hand spacing on the EMG activity of five muscles acting at the shoulder joint. Six male weight trainers performed presses under four conditions of trunk inclination... more
This experiment investigated the effects of varying bench inclination and hand spacing on the EMG activity of five muscles acting at the shoulder joint. Six male weight trainers performed presses under four conditions of trunk inclination and two of hand ...
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Assessment partnerships between staff and students are considered a vital component of the student-centred educational process. To enhance the development of this partnership in a problem-based learning curriculum, all first-year students... more
Assessment partnerships between staff and students are considered a vital component of the student-centred educational process. To enhance the development of this partnership in a problem-based learning curriculum, all first-year students were involved in generating a bank of formative assessment questions with answers, some of which were included in their final written examination. Important principles to guide development of a sound methodology for such an assessment partnership have been described. These include organisational issues as well as matters pertaining to participation, education and motivation of students and teaching staff.
Research Interests: Program Evaluation, Educational Measurement, Formative Assessment, Problem Based Learning, Health, and 15 moreTeaching, Medical Students, Humans, Female, Undergraduate medical education, Male, Young Adult, Middle Aged, Adult, First Year, SELF DIRECTED LEARNING, Curriculum and Pedagogy, Health Sciences Education, Pilot Projects, and Cooperative Behavior
The major purpose of this study was to determine the relationships between the static electromyographic (EMG) activities of trunk muscles and the angles of trunk flexion in a range of positions. Previous authors have reported trunk muscle... more
The major purpose of this study was to determine the relationships between the static electromyographic (EMG) activities of trunk muscles and the angles of trunk flexion in a range of positions. Previous authors have reported trunk muscle activation patterns during the stoop lift movement when trunk position changes relative to an external reference. When bending to prepare for a stoop lift, trunk flexor torque due to upper body weight increases as the trunk is flexed. In this study trunk flexor torque was constant because the upper body was maintained in a horizontal position while the lower body was strapped to a board whose inclination was varied between the horizontal and vertical positions in 10° increments. The length of the trunk flexor muscles increased as the trunk was flexed. Twenty young adults (10 male and 10 female) performed a total of 20 isometric contractions; 2 trials in each of 10 different postures while surface EMG of their vertebral extensor (erectores spinae an...
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Unknown-provenance osteology is the rule rather than the exception at most well-established university anatomy laboratories. This circumstance results from the difficulties associated with processing skeletons and consequent historical... more
Unknown-provenance osteology is the rule rather than the exception at most well-established university anatomy laboratories. This circumstance results from the difficulties associated with processing skeletons and consequent historical reliance on external skeleton supply - one common source is the Calcutta bone trade that operated at its peak from 1930 to 1985. This trade shipped tens-of-thousands of skeletons across the globe each year (notably without accompanying consents), potentially exceeding 2 million skeletons in total, dwarfing numbers associated with body-snatching that gave rise to the Anatomy Act in Britain. These events are extraordinary in anatomy’s history, yet it receives next to no acknowledgement in the scientific literature and countermeasures to address this situation have drawn little attention. Herein, we review articles from the popular press to provide an overarching account of the Calcutta bone trade and supplement this review with osteology from The University of Queensland’s (UQ) anatomy rooms. We outline novel and positive steps taken at The School of Biomedical Sciences to recognize and decommission unknown-provenance osteology (in all probability derived from the Calcutta bone trade) to a memorial assemblage - an action made possible via the simultaneous establishment of a new osteological collection of indefinite body donors. While the memorial assemblage cannot undo events of the past, this action awards these unknown and potentially misappropriated individuals levels of respect not previously afforded. This approach is not only favourable from an ethical standpoint, but it also offers substantially improved osteological morphologies to benefit student learning.
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Page 1. Toe-Touch Test A Measure of Its Validity VAUQHAN KIPPERS and ANTHONY W. PARKER The primary purpose of this study was to investigate the relationships between the vertical fingertip-floor distance (FFD) and ...
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ABSTRACT