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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

New strategies of acquisition and processing of encephalographic biopotentials

Nonclercq, Antoine 04 June 2007 (has links)
Electroencephalography is a medical diagnosis technique. It consists in measuring the biopotentials produced by the upper layers of the brain at various standardized places on the skull. Since the biopotentials produced by the upper parts of the brain have an amplitude of about one microvolt, the measurements performed by an EEG are exposed to many risks. Moreover, since the present tendency is measure those signals over periods of several hours, or even several days, human analysis of the recording becomes extremely long and difficult. The use of signal analysis techniques for the help of paroxysm detection with clinical interest within the electroencephalogram becomes therefore almost essential. However the performance of many automatic detection algorithms becomes significantly degraded by the presence of interference: the quality of the recordings is therefore fundamental. This thesis explores the benefits that electronics and signal processing could bring to electroencephalography, aiming at improving the signal quality and semi-automating the data processing. These two aspects are interdependent because the performance of any semi-automation of the data processing depends on the quality of the acquired signal. Special attention is focused on the interaction between these two goals and attaining the optimal hardware/software pair. This thesis offers an overview of the medical electroencephalographic acquisition chain and also of its possible improvements. The conclusions of this work may be extended to some other cases of biological signal amplification such as the electrocardiogram (ECG) and the electromyogram (EMG). Moreover, such a generalization would be easier, because their signals have a wider amplitude and are therefore more resistant toward interference.
172

The influence of proprioception, balance and plyometric strength on the occurrence of lower leg injuries in schoolboy rugby players / Johannes Hendrik Serfontein

Serfontein, Johannes Hendrik January 2006 (has links)
Background: Rugby injuries are a common phenomenon. The aim of medical professionals is to treat these injuries to the best of their abilities, and if possible, to help prevent their occurrence. Bahr and Holme (2003) argue that sports participation carries with it a risk of injury, with the even more weighty issue that it might later even lead to physical disability. Junge, Cheung, Edwards and Dvorak (2004) recommends the development and implementation of preventative interventions to reduce the rate and severity of injuries in Rugby Union. The Medical and Risk Management Committee of USA Rugby (2003) also reports that the key to preventing injuries in any sport is identifying and addressing the risk factor associated with it. Various studies have identified weakness in plyometric strength, proprioception arid balance as - of lower leg and ankle injuries (Margison, Rowlands, Gleeson arid Eston, 2005; Stasiwpoulos, 2004; Verhagen, Van der Beck, Twisk, Bahr and Mechelen, 2004; Baltaci & Kohl, 2003; Mlophy, Conaoly and Beynnon, 2003; Moss, 2002; Anderson). Aims: ThE aim of this study was to investigate the influence of proprioception, balance and plyometric strength on the occurrence of lower leg injuries in schoolboy rugby players. A further aim was to develop a preventative training programme to address these variables, should they prove to have an influence on lower leg injuries. The possible inclusion of these tests in talent identification test batteries will also be examined. Design: A prospective cohort study. Subjects: A group of 240 schoolboys in U/14, U/15, U/16 and U/18 age groups in two schools (Hoër Volkskool Potchefstroom ("Volkskool") and Potchefstroom Boys High School ("Boys High")) in the North West Province of South Africa was used as the test cohort. Method: At the beginning of the 2006 rugby season all players were tested for proprioception, balance and plyometric strength. These tests were conducted using a computerised tilt board for proprioceptive testing; Star Excursion Balance Test for Balance and an electronic timing mat for plyometric strength. During the season, weekly injury clinics were held at both schools to document all injuries that occurred following the preceding weekend's matches. A statistical analysis was done on all the data collected from the test batteries and injury clinics. Descriptive statistics (means, standard deviation, minimum and maximum) were used as well as practical significant differences (d-values) (Cohen, 1988). The ratios for left and right leg plyometric strength to bilateral plyometric strength (L+R/Bil) and individual left and right leg plyometric strength to bilateral plyometric strength (L/Bil and R/Bil) were also calculated. Results: A profile of proprioception, balance and plyometric strength was compiled for schoolboy rugby players using the test data The U/18 players generally bad the best test results of all the age groups, outperforming U/14, U/15 and U/16 players with most tests. U/15 players outperformed both U/14 and U/16 players. Backline players performed better than loose forwards and forwards in plyometric tests in most age groups. Loose-forwards also outperformed tight-forwards with plyometrics at most age groups. At U/15 and U/16 level, tight-forwards slightly outperformed loose-forwards with Star Excursion Balance Tests. Generally, A-teams performed better than B-teams with all the tests except L+R/Bil; L/Bil and R/BiI. The difference between the teams, however, only had a small to medium effect and cannot be considered practically significant. At U/14 and U/15 levels, there were more practically significant differences between the A- and B-teams, with A-teams outperforming B-teams. The tests could have some value for talent identification at this age level. A rugby epidemiological study was done on the data collected in the weekly injury clinics. This study recorded 54 injuries at the two schools involved during the 2006 season from April to July. Two hundred and forty players were involved in 10890 hours of play. Eight thousand nine hundred and ten of these player hours were practices and 1980 were match hours. These injuries occurred at a prevalence rate of 4.96/1000 player hours. Match injuries accounted for 77.78% of all injuries with training sessions resulting in the remaining 22.22% of injuries, with a match injury rate of 1 injury per individual player every 3.14 matches. U/14 players showed an overall match injury rate of 11.11/1000 match hours. U/15 players showed a rate of 2.47/1000 match hours. The low rate may be attributed to underreporting of injuries by the U/15 players. U/16 players showed a late of 22.33/1000 hours, while U/18 players showed an exceptionally high rate of 45/1000 match hours. The tackle situation was responsible for the highest percentage of injuries (57.14%). Boys High presented with more injuries (57.4%) than Volkskool at a higher prevalence rate (5.60/1000 player hours). In a positional group comparison, backline players presented with 51.85% of injuries. Since backline players only present 46.7% of players in a team, this shows that backline players have a higher risk of injury. A-team players presented with 66.6% of injuries at a prevalence rate of 6.37/1000 player hours. B-team players had an injury rate of 3.43/1000 player hours. The test values for the players suffering lower leg injuries were compared to those for uninjured players. There were eight players with nine lower leg injuries: one player had injuries of both legs. Six of the injuries were intrinsic of nature and two players had extrinsic injuries. Test values for all five tested players with intrinsic injuries were weaker by a high practically significant margin for the L+R/Bil ratio. Conclusion: L+R/Bil proved to be the test result with the most influence on the occurrence of intrinsic lower leg injuries. When the individual test results for the players with intrinsic injuries are compared to the percentiles for all players, it becomes visible that the injured players fall in the 20th percentile for both L+R/Bil and Injured leg/Bil ratios. These 20th percentile values could thus be used as a standard for determining the possible occurrence of intrinsic lower leg injuries. These 20th percentile values are 1.012 for R+L/Bil ratios; 0.483 for L/Bil ratios and 0.492 for R/Bil ratios. This study shows that plyometric ratios for L+R/Bii, L/Bil and R/Bil have an influence on lower leg injuries in schoolboy rugby players. Proprioception and balance did not have any practically significant effects on the occurrence of these injuries. A preventative training programme was also designed following a study of the literature, combined with these results. The tests could also possibly be integrated in talent identification test batteries at U/14 and U/15 level. / Thesis (M.Ed.)--North-West University, Potchefstroom Campus, 2007
173

The effect of fatigue on lower extremity mechanics during the unanticipated cutting maneuver / Title on signature form: Effect of fatigue on lower extremity mechanics during the unanticipated sidecutting maneuver

Weiss, Kaitlyn J. 04 May 2013 (has links)
Fatigue has been observed to affect lower extremity mechanics during the cutting maneuver. However, there is a lack of research examining the effect of fatigue and limb dominance on lower extremity mechanics during unanticipated sidecutting. Objectives: This research sought to assess mechanical differences pre- and post-fatigue and with respect to limb dominance. Design: Repeated measures. Methods: Thirteen female collegiate soccer and field hockey players performed right and left unanticipated sidecutting following the Yo-Yo Intermittent Recovery test (Yo-Yo IR), a two minute treadmill run at a predicted VO2max, and maximum vertical jumps. Mechanical measures of ankle, knee, and hip motion were obtained during the stance phase of the cut. Repeated measures 2x2 ANOVAs were performed to look at fatigue and limb differences. Alpha level set a priori at 0.05. Results: At initial contact and peak stance, significant changes pre- to post-fatigue were observed. At initial contact there was a reduction in knee flexion angles along with increased ankle dorsiflexion angles postfatigue. At peak stance: increased knee adductor moments post-fatigue; greater ankle eversion moments on the dominant limb (DL) as well as increased eversion moments post-fatigue for both limbs. There was a differential effect of fatigue on peak hip abduction angles and hip internal rotation angles at initial contact which were altered in the DL only; decreased hip adductor moments occurred post-fatigue as well as decreased power absorption. Conclusions: Results from this study indicate that lower extremity mechanics are altered as an effect of fatigue such that injury risk may be elevated. / School of Physical Education, Sport, and Exercise Science
174

Alternating single-leg knee extension exercise training : impact on aerobic and functional capacities / Alternating single leg knee extension exercise training

Wolff, Christopher Andrew 20 July 2013 (has links)
Access to abstract permanently restricted to Ball State community only. / Access to thesis permanently restricted to Ball State community only. / School of Physical Education, Sport, and Exercise Science
175

A Comparison of Strength Gains from Two Weight Training Programs for Fifteen Weeks of Active Exercise

Carson, Earl L. 08 1900 (has links)
Two different weight training programs were compared to determine which was most effective in improving strength. The experiment was conducted with the bench press, leg press, and sitting press for a period of fifteen weeks.
176

The relative and combined efficacy of the homoeopathic similimum (taken orally) and the topical application of a lotion (prepared from the homoeopathic mother tinctures of Hypericum perforatum and Calendula officinalis) in the treatment of venous leg ulcers

Hoffmann, Delia January 2006 (has links)
Mini-dissertation submitted in compliance with the requirements of the Master's Degree in Technology: Homoeopathy, Durban University of Technology, 2006. / The purpose of this double-blind placebo-controlled study was to evaluate the relative and combined efficacy of the homoeopathic similimum, taken orally, and the topical application of a lotion made from the homoeopathic mother tinctures of Hypericum perforatum and Calendula officinalis in the treatment of venous leg ulcers. Venous hypertension in the lower limb, occurring from a variety of causes, leads to microcirculatory abnormalities which may permit the formation of a chronic ulcer (Zimmet, 1998). Venous leg ulcers are a cause of much debility, social isolation, depression, fears of loss of employment and income (Royal College of Nursing Institute, 1998). The mainstay of treatment at present is compression bandaging to reduce the venous pressure in the lower limb. Eighty percent of venous leg ulcers will heal within eight to twelve weeks with compression bandaging (Thomas, 1997). Homoeopathy is a system of medicine based on natural laws of healing, and recognizes the biophysical energy of an individual (also known as the vital force) as that which provides the normal protective defence mechanisms of the body, and is disturbed in disease, producing symptoms on the physical, mental and emotional levels (Vithoulkas, 1980). Many plants are known to have wound-healing properties (Curtis and Fraser, 2003). Calendula officinalis and Hypericum perforatum were considered the best plants in a homoeopathic lotion to be used on chronic venous leg ulcers, as they cover all the common problems associated with this type of wound, providing pain relief and anti-microbial activity (Lawless, 1995). In this study, homoeopathic mother tinctures of the herbs were used to make the lotion for topical application to the wounds. / M
177

Caracterização de plantas transgênicas expressando a Leghemoglobina de soja no interior de mitocôndrias e cloroplastos / not available

Delneri, Ana Lúcia Bonna 07 December 2001 (has links)
O oxigênio atua como substrato ou cofator numa série de reações bioquímicas do metabolismo primário e secundário das plantas. Várias estratégias têm sido utilizadas no sentido de interferir neste metabolismo aeróbico, visando, entre outras possibilidades, reduzir a formação de espécies reativas de oxigênio (ROS). A fim de alterar a disponibilidade de oxigênio no interior da organela, foram produzidas plantas de fumo (Nicotiana tabacum) expressando a leghemoglobina de soja no interior das mitocôndrias. Para tanto, as plantas foram transformadas, via Agrobacterium tumefaciens, com uma construção quimérica, onde o gene da Lba de soja foi fusionado a uma seqüência de direcionamento mitocondrial. A expressão do gene quimérico foi assegurada pela presença do promotor constitutivo 35S, do vírus do mosaico da couve-flor. A proteína foi corretamente importada e processada no interior das mitocôndrias. Entretanto, não foi possível detectar alterações significativas na função mitocondrial. Numa segunda etapa do presente trabalho, plantas transgênicas de batata (Solanum tuberosum cv Bintje) expressando a leghemoglobina de soja no interior dos cloroplastos, foram caracterizadas do ponto de vista molecular e fenotípico. Observou-se que as plantas apresentaram um fenótipo semelhante àquelas deficientes na biossíntese de giberelina / not available
178

Hormonal Response to Free Weight and Machine Weight Resistance Exercise

Shaner, Aaron Arthur 08 1900 (has links)
No study has examined the effect of exercise modality (free weight vs. machine weight) on the acute hormonal response using similar multi-joint exercises. The purpose of this investigation was to examine the effect of resistance exercise modality on acute hormonal responses by comparing the squat and leg press which are multi-joint, and similar in action and lower-body muscle involvement. Ten resistance trained men (21-31 y, 24.7 ± 2.9 y, 179 ± 7 cm, 84.2 ± 10.5 kg) participated in the study. Sessions 1 and 2 determined the participants’ 1-RM in the squat and leg press. During acute heavy resistance exercise testing visits (AHRET), sessions 3 and 4, participants completed 6 sets of 10 repetitions with an initial intensity of 80% of their 1-RM for the squat and leg press exercises. There was a 2 minute rest period between each set. Blood samples were collected before, immediately after, and 15 and 30 minutes after exercise via intravenous catheter during the AHRET visits and were analyzed for testosterone, cortisol, and growth hormone. Lactate, plasma volume change, heart rates and ratings of perceived exertion were also measured. Total work was calculated for external load only and for external load and the body mass used in the exercises. The 4 sessions were counterbalanced and randomized for exercise mode. Testosterone for the squat (Pre: 23.9 ± 8.7 nmol•L-1; IP: 31.4 ± 10.3 nmol•L) and leg press (Pre: 22.1 ± 9.4 nmol•L-1; IP: 26.9 ± 7.8 nmol•L) increased but more significantly after the squat. Growth hormone increased in both the squat (Pre: 0.2 ± 0.2 µg/L; IP: 9.5 ± 7.3 µg/L) and the leg press (Pre: 0.3 ± 0.5 µg/L; IP: 2.8 ± 3.2 µg/L). The increase was significantly higher after the squat compared to the leg press. Cortisol also increased after performing the squat (Pre: 471.9 ± 167.2 nmol•L-1; IP: 603.2 ± 277.6 nmol•L) and leg press (Pre: 463.5 ± 212.4 nmol•L-1; IP: 520.3 ± 270.3 nmol•L), but there was no significant difference between the two modes. The total work was significantly higher in the squat (60509 ± 10759 j) compared to the leg press (42875 ± 7010). The squat exercise is more effective at inducing an acute hormonal response. If the leg press exercise is used, the hormonal response may be reduced, which might lead to reduced training adaptations, especially when only a 90º knee angle ROM is used. To induce the maximal hormonal response to resistance exercise, free weight exercises should be used.
179

Exploring the experiences of injecting drug users living with leg ulceration : a qualitative design

Geraghty, Jemell January 2018 (has links)
There is a paucity of scientific evidence into the lived experience of people who have a history of injecting drug use and are living with leg ulceration. Portraying the true voice of injecting drug users (IDUs) through narrative means is a novelty in contemporary literature. The representation of the life and the person behind the leg ulcer, having experienced addiction, is original from a purist narrative perspective. This study, led from the perspective of a nurse-researcher leading in the field of wound management, offers a unique opportunity to gain a rare glimpse into the daily life of IDUs, as reported in their own words. The aim of this study was to explore the experience of injecting drug users living with leg ulceration using qualitative methodology. A naturalistic paradigm framed the design by allowing participants to control the data in an unrestricted an open manner without direct intrusion form the researcher. Qualitative methodology was central to collecting data on life experience and feelings. The ethics process detailed a rigorous application to explore the professional, ethical virtues from the perspective of an insider-outsider working with sensitive data in a marginalised population. Diaries were kept and recorded by participants over four weeks in their routine daily life; this was followed by semi-structured interviews. The diaries allowed a unique insight into the past, present and future of IDUs and how their ulcer affected their lives. The diaries also facilitated a means of reflection on themselves and their wounded body. The interviews offered an opportunity to explore in detail the diary entries and other stories participants wished to share. The study recruited twelve participants from leg ulcer clinics set in London; three women and nine men older than 18 years of age (median age of 52 years; range 35 - 62 years). Ten completed the data collection process; two of the participants, aged 61 and 62 years, were married. Gatekeepers working with IDUs with leg ulceration were central to the process of engagement and recruitment. Participants welcomed the design as an opportunity to voice and share their journey of living with an open wound. The findings revealed the detailed suffering participants endured living with their ulcer: pain, shame and stigma were clearly voiced in their narratives. The majority of participants had experienced some form of stigma during their life and this was exacerbated as they were drug users. The self-blame and punishment triggered by this felt stigma was a detriment to the health of participants. Those in contact with specialist wound care services saw a significant improvement in wound healing and this had a positive impact on their wellbeing and their overall outlook on life. Participants also voiced enacted-stigma experienced from encounters in health practice. These negative experiences exacerbated the self-stigma. Findings also portrayed the multiple characteristics and talents of participants including humour, art and resilience. This research contributes to science and practice by understanding the lives of IDUs living with leg ulceration. It provides a platform from which to engage both generalists and specialists who care for these patients and has the potential to influence medical and social policy-making and clinical practice in this field. By means of narrative inquiry, this study may challenge the conventional social stereotypes, the taboos and the stigma still experienced by this patient group in health care.
180

Effects of Various Mobility Aids on Lower-Extremity Muscle Activity

Sanders, Michael Ryan 01 December 2015 (has links)
Millions of people each year spend some portion of their time using mobility aids to facilitate periods of non-weight bearing ambulation. The use of these devices changes the loading conditions of the lower extremities, which may result in skeletal muscle adaptations. The purpose of this work was to evaluate the effects of 3 types of mobility aids on lower-extremity muscle activity. Evaluation was based on 1) measured muscle activation signals using electromyography (EMG), and 2) measured joint kinematics and ground reaction forces, which were used to predict muscle forces. 16 healthy subjects (7 female, 9 male), ages 18-27 participated in the study. Subjects were instructed to ambulate using each of three mobility aids (crutches, a knee scooter and a temporary-injury prosthesis) as well as normal walking. EMG and motion capture were used to obtain bilateral data from the lower half of the body during ambulation on each of these mobility aids and walking (10 trials on each per subject). Muscles studied were right and left vastus lateralis (VLR, VLL), rectus femoris (RFR, RFL), Biceps femoris long head (BFR, BFL), and gastrocnemius medialis (GMR, GML). Joint kinematics and ground reaction force data (joint kinetics) were acquired using a standard camera-based motion capture system. The measured joint kinetics were used as inputs to the open source musculoskeletal biomechanics software OpenSim (SimTK, Stanford, CA), which allowed prediction of muscle force data for a representative subject during each mode of ambulation. As compared to walking, the following differences in EMG activation were significant. For the knee scooter, increases in VLR, RFR, BFL and decreases in GMR. For the TI prosthesis, increases in VLR, RFR, BFR, VLL, RFL, GML and decreases in GMR. For crutches, increases in BFR, VLL, RFL, BFL, GML and decreases in VLR, GMR. Muscle force results were similar, but demonstrated inadequacy of current musculoskeletal simulation software to resolve muscle forces during non-weight bearing portions of gait based solely on kinetic data. Results for walking data were similar to what is reported in the literature for normal gait. This study provides useful bilateral data that describe measured lower-extremity EMG activation amplitudes and muscle force predictions based on kinetic data during ambulation using three different ambulatory aids, compared to normal walking. Based on a criteria of maintaining muscle activation, the TI prosthesis proved most effective among the devices tested. The data presented will be valuable to clinicians in providing insight into which mobility aid may be best suited for a particular patient. It is anticipated that these data will provide designers of mobility aids with a protocol for evaluation of designs based on their potential to cause or prevent muscle adaptations.

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