The effects of age on the worker capacity and mechanisation on the task demands in a South African manufacturing industry
- Bezuidenhout, Samantha Catherine
- Authors: Bezuidenhout, Samantha Catherine
- Date: 2014
- Subjects: Age and employment -- South Africa , Labor -- Social aspects -- South Africa , Brickmaking -- South Africa -- Automation , Brickmaking -- Social aspects -- South Africa , Brick trade -- South Africa , Aging -- Social aspects -- South Africa , Aging -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5151 , http://hdl.handle.net/10962/d1013167
- Description: The focus of the study was two-fold, firstly to determine the effect of age on the capacity of manual materials handling workers and secondly to determine the effect of increasing task mechanisation on the workers’ responses to task demands. The first component of this study, namely Part I, 101 male and 12 female ‘unskilled’ manual workers – of various ages – from a brick manufacturing industry were assessed. Anthropometric, health and strength factors were measured to improve the understanding of the South African manual worker capacity and more specifically, the effect of age on this capacity. Data collection was done between 7.30am and 9.30am in a laboratory-type setting on-site. Anthropometric characteristics (including body mass index, waist to hip ratio, waist circumference and body fat percentage) provided information on the state of obesity and the impact of age in the South African context. Linked to this, the health factors (including blood pressure, resting heart rate and a self-reported questionnaire) provide an extra snapshot of the disease profile in South Africa, and could potentially influence other capacity factors. Isometric strength capacities (of eight different areas, namely: back, leg, bicep, shoulder, pinch, pinch and pull) demonstrated whether South African manual workers show the same decline in strength with aging as seen in industrially advanced countries. The second component of the study, Part II, was performed in situ and measured the workers’ responses to task demands of three brick palletising tasks, one manual (n=21) and two with increasing mechanisation (n=12 each). Spinal kinematics, joint forces and working heart rate were assessed on normal work days during a 30-lift duration and body discomfort measures were taken at the start, middle and end of the work-shift. Spinal kinematics were measured dynamically using a lumbar motion monitor, whereas the spinal forces were estimated using the three dimensional static strength prediction program. The worker capacity results showed that waist to hip ratio, waist circumference and body fat percentage increased significantly with aging, whereas body mass index was not affected by age. All body morphology values were within ‘normal’ ranges. Although diastolic blood pressure increased significantly with age, systolic was not affected significantly by age. Both groups, however, showed an increasing prevalence of hypertension with aging. There were no significant changes in resting heart rate with aging, with a range of 66 bt.min⁻¹ to 74.86 bt.min⁻¹, therefore within normal ranges. Of the strength factors, age only affected shoulder and push strength significantly: Showing a decrease in shoulder strength from 49.89 kgF to 39.91 kgF in the men aged 20-29 to the 50-59 respectively and an increase in push strength from men aged 30-39 and 40-49 to those aged 50-59. Part II results revealed highly frequent lift rates and large degrees of sagittal flexion and lateral bending in all three tasks. These postures adopted for long durations are likely to lead to the development of musculoskeletal disorders. Heart rates of workers from the three tasks were significantly different and heart rates for two tasks were above the recommended 110 bt.min⁻¹. Similarly the body discomfort ratings of the three tasks differed, although a common trend was seen in that lower back pain was the most commonly reported area of discomfort in all tasks. South African manual materials handling males did not show the same responses to aging as men from industrially advanced countries, calling for further research into these differences. Due to the high risks of the three tasks assessed, future research and interventions are required to reduce the risk of injury in the assessed tasks.
- Full Text:
- Date Issued: 2014
- Authors: Bezuidenhout, Samantha Catherine
- Date: 2014
- Subjects: Age and employment -- South Africa , Labor -- Social aspects -- South Africa , Brickmaking -- South Africa -- Automation , Brickmaking -- Social aspects -- South Africa , Brick trade -- South Africa , Aging -- Social aspects -- South Africa , Aging -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5151 , http://hdl.handle.net/10962/d1013167
- Description: The focus of the study was two-fold, firstly to determine the effect of age on the capacity of manual materials handling workers and secondly to determine the effect of increasing task mechanisation on the workers’ responses to task demands. The first component of this study, namely Part I, 101 male and 12 female ‘unskilled’ manual workers – of various ages – from a brick manufacturing industry were assessed. Anthropometric, health and strength factors were measured to improve the understanding of the South African manual worker capacity and more specifically, the effect of age on this capacity. Data collection was done between 7.30am and 9.30am in a laboratory-type setting on-site. Anthropometric characteristics (including body mass index, waist to hip ratio, waist circumference and body fat percentage) provided information on the state of obesity and the impact of age in the South African context. Linked to this, the health factors (including blood pressure, resting heart rate and a self-reported questionnaire) provide an extra snapshot of the disease profile in South Africa, and could potentially influence other capacity factors. Isometric strength capacities (of eight different areas, namely: back, leg, bicep, shoulder, pinch, pinch and pull) demonstrated whether South African manual workers show the same decline in strength with aging as seen in industrially advanced countries. The second component of the study, Part II, was performed in situ and measured the workers’ responses to task demands of three brick palletising tasks, one manual (n=21) and two with increasing mechanisation (n=12 each). Spinal kinematics, joint forces and working heart rate were assessed on normal work days during a 30-lift duration and body discomfort measures were taken at the start, middle and end of the work-shift. Spinal kinematics were measured dynamically using a lumbar motion monitor, whereas the spinal forces were estimated using the three dimensional static strength prediction program. The worker capacity results showed that waist to hip ratio, waist circumference and body fat percentage increased significantly with aging, whereas body mass index was not affected by age. All body morphology values were within ‘normal’ ranges. Although diastolic blood pressure increased significantly with age, systolic was not affected significantly by age. Both groups, however, showed an increasing prevalence of hypertension with aging. There were no significant changes in resting heart rate with aging, with a range of 66 bt.min⁻¹ to 74.86 bt.min⁻¹, therefore within normal ranges. Of the strength factors, age only affected shoulder and push strength significantly: Showing a decrease in shoulder strength from 49.89 kgF to 39.91 kgF in the men aged 20-29 to the 50-59 respectively and an increase in push strength from men aged 30-39 and 40-49 to those aged 50-59. Part II results revealed highly frequent lift rates and large degrees of sagittal flexion and lateral bending in all three tasks. These postures adopted for long durations are likely to lead to the development of musculoskeletal disorders. Heart rates of workers from the three tasks were significantly different and heart rates for two tasks were above the recommended 110 bt.min⁻¹. Similarly the body discomfort ratings of the three tasks differed, although a common trend was seen in that lower back pain was the most commonly reported area of discomfort in all tasks. South African manual materials handling males did not show the same responses to aging as men from industrially advanced countries, calling for further research into these differences. Due to the high risks of the three tasks assessed, future research and interventions are required to reduce the risk of injury in the assessed tasks.
- Full Text:
- Date Issued: 2014
The effect of load and technique on biomechanical and perceptual responses during dynamic pushing and pulling
- Authors: Desai, Sheena Dhiksha
- Date: 2009
- Subjects: Work -- Physiological aspects , Biomechanics , Human engineering , Lifting and carrying
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5109 , http://hdl.handle.net/10962/d1005187 , Work -- Physiological aspects , Biomechanics , Human engineering , Lifting and carrying
- Description: Changes in the industrial job profile, from lifting and lowering to repetitive dynamic pushing and pulling have been facilitated through the use of manual vehicles, aimed at minimising the workload. Yet, the demands of pushing and pulling have not been well documented. Using measures of the horizontal component of the hand forces, spinal kinematics, muscle activity at various sites on the upper body and body discomfort ratings, this study aimed at quantifying the biomechanical and perceptual demands of various dynamic push/pull techniques. 36 healthy male participants performed two-handed forward pushing, two-handed backward pulling and one-handed forward pulling, employing an industrial pallet jack supporting two loads of 250kg or 500kg. While no single technique was definitively identified as preferable regarding hand forces, pushing at 500kg elicited higher initial and sustained forces (p<0.05) than one- and two-handed pulling respectively. Increments in load mass from 250kg to 500kg resulted in significant differences in the initial, sustained and ending forces. With regard to spinal kinematics in the sagittal plane, two-handed pulling elicited the highest trunk flexion, and may therefore expose individuals to prolonged forward bending. Generally this technique was found to evoke the highest sagittal responses. Spinal kinematic measures in the lateral and transverse planes suggested that one-handed pulling was accompanied by the highest measures, and hence the greatest risk of developing lower back disorders related to this plane. Although various combinations of muscles were active during each technique, one-handed pulling and pushing, most often induced the highest muscle activation levels and two-handed pulling, the lowest. While erector spinae evidenced no significant differences between techniques at each load or between loads for the same technique, activation levels were high under all conditions. Perceptual ratings of body discomfort revealed that not only is the upper body susceptible to injuries during pushing and pulling, but also that the lower extremities may have a considerable role to play in these tasks, with the calves being a particular area of concern. Findings concluded that symmetrical pushing and pulling tasks are preferable.
- Full Text:
- Date Issued: 2009
- Authors: Desai, Sheena Dhiksha
- Date: 2009
- Subjects: Work -- Physiological aspects , Biomechanics , Human engineering , Lifting and carrying
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5109 , http://hdl.handle.net/10962/d1005187 , Work -- Physiological aspects , Biomechanics , Human engineering , Lifting and carrying
- Description: Changes in the industrial job profile, from lifting and lowering to repetitive dynamic pushing and pulling have been facilitated through the use of manual vehicles, aimed at minimising the workload. Yet, the demands of pushing and pulling have not been well documented. Using measures of the horizontal component of the hand forces, spinal kinematics, muscle activity at various sites on the upper body and body discomfort ratings, this study aimed at quantifying the biomechanical and perceptual demands of various dynamic push/pull techniques. 36 healthy male participants performed two-handed forward pushing, two-handed backward pulling and one-handed forward pulling, employing an industrial pallet jack supporting two loads of 250kg or 500kg. While no single technique was definitively identified as preferable regarding hand forces, pushing at 500kg elicited higher initial and sustained forces (p<0.05) than one- and two-handed pulling respectively. Increments in load mass from 250kg to 500kg resulted in significant differences in the initial, sustained and ending forces. With regard to spinal kinematics in the sagittal plane, two-handed pulling elicited the highest trunk flexion, and may therefore expose individuals to prolonged forward bending. Generally this technique was found to evoke the highest sagittal responses. Spinal kinematic measures in the lateral and transverse planes suggested that one-handed pulling was accompanied by the highest measures, and hence the greatest risk of developing lower back disorders related to this plane. Although various combinations of muscles were active during each technique, one-handed pulling and pushing, most often induced the highest muscle activation levels and two-handed pulling, the lowest. While erector spinae evidenced no significant differences between techniques at each load or between loads for the same technique, activation levels were high under all conditions. Perceptual ratings of body discomfort revealed that not only is the upper body susceptible to injuries during pushing and pulling, but also that the lower extremities may have a considerable role to play in these tasks, with the calves being a particular area of concern. Findings concluded that symmetrical pushing and pulling tasks are preferable.
- Full Text:
- Date Issued: 2009
The development and evaluation of a custom-built synchronous online learning environment for tertiary education in South Africa
- Authors: Halse, Michelle Louise
- Date: 2008 , 2008-02-23
- Subjects: Education, Higher -- South Africa -- Computer-assisted instruction , Universities and colleges -- Computer networks -- South Africa , Internet in higher education -- South Africa , Distance education -- South Africa -- Computer-assisted instruction , Computer-assisted instruction -- South Africa , Computer science -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4636 , http://hdl.handle.net/10962/d1006545 , Education, Higher -- South Africa -- Computer-assisted instruction , Universities and colleges -- Computer networks -- South Africa , Internet in higher education -- South Africa , Distance education -- South Africa -- Computer-assisted instruction , Computer-assisted instruction -- South Africa , Computer science -- Study and teaching (Higher) -- South Africa
- Description: The Departments of Computer Science and Information Systems at Rhodes University currently share certain honours-level (fourth year) course modules with students from the corresponding departments at the previously disadvantaged University of Fort Hare. These lectures are currently delivered using video-conferencing. This was found to present a number of problems including challenges in terms of implementing desired pedagogical approaches, inequitable learning experiences, student disengagement at the remote venue, and inflexibility of the video-conferencing system. In order to address these problems, various e-learning modes were investigated and synchronous e-learning were found to offer a number of advantages over asynchronous e-learning. Live Virtual Classrooms (LVCs) were identified as synchronous e-learning tools that support the pedagogical principles important to the two universities and to the broader context of South African tertiary education, and commercial LVC applications were investigated and evaluated. Informed by the results of this investigation a small, simple LVC was designed, developed and customised for use in a predominantly academic sphere and deployment in a South African tertiary educational context. Testing and evaluation of this solution was carried out and the results analysed in terms of the LVC’s technical merits and the pedagogical value of the solution as experienced by students and lecturers/facilitators. An evaluation of this solution indicated that the LVC solves a number of the identified problems with video-conferencing and also provides a flexible/customisable/extensible solution that supports highly interactive, collaborative, learner-centred education. The custom LVC solution could be easily adapted to the specific needs of any tertiary educational institute in the country, and results may benefit other tertiary educational institutions involved in or dependant on distance learning.
- Full Text:
- Date Issued: 2008
- Authors: Halse, Michelle Louise
- Date: 2008 , 2008-02-23
- Subjects: Education, Higher -- South Africa -- Computer-assisted instruction , Universities and colleges -- Computer networks -- South Africa , Internet in higher education -- South Africa , Distance education -- South Africa -- Computer-assisted instruction , Computer-assisted instruction -- South Africa , Computer science -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4636 , http://hdl.handle.net/10962/d1006545 , Education, Higher -- South Africa -- Computer-assisted instruction , Universities and colleges -- Computer networks -- South Africa , Internet in higher education -- South Africa , Distance education -- South Africa -- Computer-assisted instruction , Computer-assisted instruction -- South Africa , Computer science -- Study and teaching (Higher) -- South Africa
- Description: The Departments of Computer Science and Information Systems at Rhodes University currently share certain honours-level (fourth year) course modules with students from the corresponding departments at the previously disadvantaged University of Fort Hare. These lectures are currently delivered using video-conferencing. This was found to present a number of problems including challenges in terms of implementing desired pedagogical approaches, inequitable learning experiences, student disengagement at the remote venue, and inflexibility of the video-conferencing system. In order to address these problems, various e-learning modes were investigated and synchronous e-learning were found to offer a number of advantages over asynchronous e-learning. Live Virtual Classrooms (LVCs) were identified as synchronous e-learning tools that support the pedagogical principles important to the two universities and to the broader context of South African tertiary education, and commercial LVC applications were investigated and evaluated. Informed by the results of this investigation a small, simple LVC was designed, developed and customised for use in a predominantly academic sphere and deployment in a South African tertiary educational context. Testing and evaluation of this solution was carried out and the results analysed in terms of the LVC’s technical merits and the pedagogical value of the solution as experienced by students and lecturers/facilitators. An evaluation of this solution indicated that the LVC solves a number of the identified problems with video-conferencing and also provides a flexible/customisable/extensible solution that supports highly interactive, collaborative, learner-centred education. The custom LVC solution could be easily adapted to the specific needs of any tertiary educational institute in the country, and results may benefit other tertiary educational institutions involved in or dependant on distance learning.
- Full Text:
- Date Issued: 2008
Isolation, propagation and rapid molecular detection of the Kalahari truffle, a mycorrhizal fungus occurring in South Africa
- Authors: Adeleke, Rasheed Adegbola
- Date: 2007 , 2013-04-03
- Subjects: Truffles -- Kalahari Desert , Fungi -- Identification , Mycorrhizal fungi -- South Africa , Edible fungi -- South Africa , Mushroom culture -- South Africa , Fungi -- Cultures and culture media -- South Africa , Truffles -- South Africa , Truffles -- Lifecycles , Mycorrhizal fungi -- Lifecycles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3889 , http://hdl.handle.net/10962/d1002951 , Truffles -- Kalahari Desert , Fungi -- Identification , Mycorrhizal fungi -- South Africa , Edible fungi -- South Africa , Mushroom culture -- South Africa , Fungi -- Cultures and culture media -- South Africa , Truffles -- South Africa , Truffles -- Lifecycles , Mycorrhizal fungi -- Lifecycles
- Description: Terfezia pfeilii is an edible mycorrhizal fungus that thrives in the Kalahari Desert of southern Africa. It is best known by desert dwellers for its flavour and as a source of nutrition. Although the genus Terfezia is generally regarded as being an ectomycorrhizal mycobiont, the exact mycorrhizal type formed by T. pfeilli and its' associated host plants remains uncertain. Discovery of the host plants for T. pfeilii would first be required in order to further investigate the life cycle and cultivation of this truffle. This study focussed on the isolation of mycelia from the ascocarp, optimising the growth conditions of the mycelial cultures, rapid molecular identification of T. pfeilii, investigation of potential helper bacteria and mycorrhizal synthesis experiments. T. pfeilii ascocarps were harvested from the Spitskop Nature Reserve in Upington, South Africa. Ascocarps were successfully identified using both morphological and molecular methods. Despite the delayed growth mostly caused by contaminating microorganisms, the isolation of T. pfeilii mycelia culture was successful. Molecular techniques were used to confirm the identity of the pure culture. Further studies were conducted on ways to improve the growth conditions of the mycelial culture on Fontana medium. An optimum temperature of 32°C, the addition of Bovine Serum Albumin as a nitrogen source and a pH of 7.5 significantly improved the growth of T. pfeilii in vitro. A rapid PeR-based molecular method was developed to speed up the identification of T. pfeilii. Specific primers that can exclusively amplify the ITS region of T. pfeilii were designed and used to identify both the ascocarps and the mycelial culture. The specificity of these primers was confirmed by their inability to amplify DNA from the isolates of contamining fungi obtained during the isolation process. Molecular comparison was made to confirm the reclassification of South African samples of T. pfeilii as Kalaharituber pfeilii as proposed by Ferdman et al.,(2005). However, in this study, the name T. pfeilii has been retained. A total of 17 bacterial isolates were obtained from the fruiting bodies of T. pfeaii and these were tested for stimulation of mycelial growth in vitro, indole production and phosphate solubilising capabilities. Bacterial isolates that showed potential to be Mycorrhization Helper Bacteria (MHB) were identified as Paenibacillus sp., Bacillus sp. and Rhizobium tropici. Selected plant seedlings were inoculated with T. pfeilii cultures or ascocarp slurry in order to re-establish the mycorrhizal association. After 8 months, light microscopy observations revealed an endomycorrhizal type association between Cynodon dactylon and T. pfeilii. This was confirmed with molecular analysis using specific T. pfeilii ITS primers. After 15 months, molecular methods confirmed Acacia erioloba as another host plant. These results have provided essential information paving the way for further investigation into the life cycle and biology of the Kalahari truffle. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2007
- Authors: Adeleke, Rasheed Adegbola
- Date: 2007 , 2013-04-03
- Subjects: Truffles -- Kalahari Desert , Fungi -- Identification , Mycorrhizal fungi -- South Africa , Edible fungi -- South Africa , Mushroom culture -- South Africa , Fungi -- Cultures and culture media -- South Africa , Truffles -- South Africa , Truffles -- Lifecycles , Mycorrhizal fungi -- Lifecycles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3889 , http://hdl.handle.net/10962/d1002951 , Truffles -- Kalahari Desert , Fungi -- Identification , Mycorrhizal fungi -- South Africa , Edible fungi -- South Africa , Mushroom culture -- South Africa , Fungi -- Cultures and culture media -- South Africa , Truffles -- South Africa , Truffles -- Lifecycles , Mycorrhizal fungi -- Lifecycles
- Description: Terfezia pfeilii is an edible mycorrhizal fungus that thrives in the Kalahari Desert of southern Africa. It is best known by desert dwellers for its flavour and as a source of nutrition. Although the genus Terfezia is generally regarded as being an ectomycorrhizal mycobiont, the exact mycorrhizal type formed by T. pfeilli and its' associated host plants remains uncertain. Discovery of the host plants for T. pfeilii would first be required in order to further investigate the life cycle and cultivation of this truffle. This study focussed on the isolation of mycelia from the ascocarp, optimising the growth conditions of the mycelial cultures, rapid molecular identification of T. pfeilii, investigation of potential helper bacteria and mycorrhizal synthesis experiments. T. pfeilii ascocarps were harvested from the Spitskop Nature Reserve in Upington, South Africa. Ascocarps were successfully identified using both morphological and molecular methods. Despite the delayed growth mostly caused by contaminating microorganisms, the isolation of T. pfeilii mycelia culture was successful. Molecular techniques were used to confirm the identity of the pure culture. Further studies were conducted on ways to improve the growth conditions of the mycelial culture on Fontana medium. An optimum temperature of 32°C, the addition of Bovine Serum Albumin as a nitrogen source and a pH of 7.5 significantly improved the growth of T. pfeilii in vitro. A rapid PeR-based molecular method was developed to speed up the identification of T. pfeilii. Specific primers that can exclusively amplify the ITS region of T. pfeilii were designed and used to identify both the ascocarps and the mycelial culture. The specificity of these primers was confirmed by their inability to amplify DNA from the isolates of contamining fungi obtained during the isolation process. Molecular comparison was made to confirm the reclassification of South African samples of T. pfeilii as Kalaharituber pfeilii as proposed by Ferdman et al.,(2005). However, in this study, the name T. pfeilii has been retained. A total of 17 bacterial isolates were obtained from the fruiting bodies of T. pfeaii and these were tested for stimulation of mycelial growth in vitro, indole production and phosphate solubilising capabilities. Bacterial isolates that showed potential to be Mycorrhization Helper Bacteria (MHB) were identified as Paenibacillus sp., Bacillus sp. and Rhizobium tropici. Selected plant seedlings were inoculated with T. pfeilii cultures or ascocarp slurry in order to re-establish the mycorrhizal association. After 8 months, light microscopy observations revealed an endomycorrhizal type association between Cynodon dactylon and T. pfeilii. This was confirmed with molecular analysis using specific T. pfeilii ITS primers. After 15 months, molecular methods confirmed Acacia erioloba as another host plant. These results have provided essential information paving the way for further investigation into the life cycle and biology of the Kalahari truffle. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2007
Physiological, perceptual and performance responses during cricket activity
- Authors: King, Gregory Allen
- Date: 2003
- Subjects: Cricket , Sports -- Psychological aspects , Sports -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5131 , http://hdl.handle.net/10962/d1005210 , Cricket , Sports -- Psychological aspects , Sports -- Physiological aspects
- Description: The present study sought to determine the influence of environmental conditions and protective clothing on physiological, perceptual and performance responses during batting activity. The investigation examined mean skin temperature, average heart rate, estimated sweat rate, rating of perceived exertion, thermal sensation rating, average sprint time and pre-post choice reaction time. Twenty-five cricketers (18-22 yr, 73.1 ± 9.6 kg, 1768 ± 75 mm, 12.6 ± 3.1% body fat, 1.89 ± 0.16 m2) performed a work-bout consisting of a seven-Over batting period, during which time they faced deliveries from a bowling machine and performed two shuttle runs every third ball to total four sprints per Over. Trials were carried out under High-stress (23.8 ± 2.2 °C) and Low-stress (13.3 ± 1.9 °C) environmental conditions (WBGT). Within each environmental condition subjects performed the test wearing full protective batting gear and no protective gear. Thus, four specific conditions were examined; high full-gear (HFG), high no-gear (HNG), low full-gear (LFG) and low no-gear (LNG). Two-way ANOVAs were calculated to determine whether there were differences between environmental conditions and whether differences existed between the clothing conditions. One-way ANOVAs were utilised to compute differences between the four specific conditions combining clothing and environment. High environmental stress and wearing protective clothing caused batsmen to experience significant physiological strain. The environment was the greatest stressor, with the protective gear exacerbating these effects. However, when padding covered skin areas directly, this was the primary skin temperature stressor, particularly later in the activity. For skin temperature and heart rate, the strain was the most pronounced at the end of the trials. Perceptual responses indicated that the protective gear had no influence on effort sense, thermal sensation or thermal comfort. However, environmental conditions had an effect, and High-stress conditions resulted in significantly higher perceptions of effort, elevated sensations of heat and greater thermal discomfort. Effort was perceived to be greatest towards the end of the trial. There were mixed findings for performance factors. In general sprint performance was not hindered by environmental stress, but protective clothing caused a reduction in several sprint times. Choice reaction times were for the most part unaffected by either environment or clothing and few differences were observed between pre and post times. It is contended that intense short duration batting activity, likely encountered during one-day participation, imposes a stress on batsmen. The stress is greater when conditions are warmer and protective padding is worn, although it is not sufficient to impede choice reaction time. However, protective gear did have a deleterious effect on sprint performance.
- Full Text:
- Date Issued: 2003
- Authors: King, Gregory Allen
- Date: 2003
- Subjects: Cricket , Sports -- Psychological aspects , Sports -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5131 , http://hdl.handle.net/10962/d1005210 , Cricket , Sports -- Psychological aspects , Sports -- Physiological aspects
- Description: The present study sought to determine the influence of environmental conditions and protective clothing on physiological, perceptual and performance responses during batting activity. The investigation examined mean skin temperature, average heart rate, estimated sweat rate, rating of perceived exertion, thermal sensation rating, average sprint time and pre-post choice reaction time. Twenty-five cricketers (18-22 yr, 73.1 ± 9.6 kg, 1768 ± 75 mm, 12.6 ± 3.1% body fat, 1.89 ± 0.16 m2) performed a work-bout consisting of a seven-Over batting period, during which time they faced deliveries from a bowling machine and performed two shuttle runs every third ball to total four sprints per Over. Trials were carried out under High-stress (23.8 ± 2.2 °C) and Low-stress (13.3 ± 1.9 °C) environmental conditions (WBGT). Within each environmental condition subjects performed the test wearing full protective batting gear and no protective gear. Thus, four specific conditions were examined; high full-gear (HFG), high no-gear (HNG), low full-gear (LFG) and low no-gear (LNG). Two-way ANOVAs were calculated to determine whether there were differences between environmental conditions and whether differences existed between the clothing conditions. One-way ANOVAs were utilised to compute differences between the four specific conditions combining clothing and environment. High environmental stress and wearing protective clothing caused batsmen to experience significant physiological strain. The environment was the greatest stressor, with the protective gear exacerbating these effects. However, when padding covered skin areas directly, this was the primary skin temperature stressor, particularly later in the activity. For skin temperature and heart rate, the strain was the most pronounced at the end of the trials. Perceptual responses indicated that the protective gear had no influence on effort sense, thermal sensation or thermal comfort. However, environmental conditions had an effect, and High-stress conditions resulted in significantly higher perceptions of effort, elevated sensations of heat and greater thermal discomfort. Effort was perceived to be greatest towards the end of the trial. There were mixed findings for performance factors. In general sprint performance was not hindered by environmental stress, but protective clothing caused a reduction in several sprint times. Choice reaction times were for the most part unaffected by either environment or clothing and few differences were observed between pre and post times. It is contended that intense short duration batting activity, likely encountered during one-day participation, imposes a stress on batsmen. The stress is greater when conditions are warmer and protective padding is worn, although it is not sufficient to impede choice reaction time. However, protective gear did have a deleterious effect on sprint performance.
- Full Text:
- Date Issued: 2003
Stability of prochlorperazine in solution and in the solid-state
- Authors: Antunes, Edith Martins
- Date: 2000
- Subjects: Phenothiazine
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4536 , http://hdl.handle.net/10962/d1016399
- Description: Prochlorperazine, a member of the piperazine subclass of phenothiazines, widely used as an anti-emetic, is susceptible to oxidation to sulfoxides. These are main metabolites and degradants of all phenothiazines which are found to be inactive at the dopamine receptors. Prochlorperazine causes photosensitivity effects in patients attributed to dechlorination at C2 with the release of HCI (Huang and Sands, 1967; Nejmeh and Pilpel, 1978; Moore and Tamat, 1980). The aim of this study is to investigate the thermal and photostability of prochlorperazine edisylate and mesylate salts in the solid state and in solution. Prochlorperazine is available as a fine chemical and in a variety of dosage forms, including injectables and tablets. According to ICH guidelines, any degradants greater than 0.1 % are required to be isolated and identified. In order to assess the photostability of the two salts, an HPLC method was developed and validated for linearity, accuracy and precision, selectivity, limit of detection, quantitation and ruggedness. Sulfoxides were synthesised for use as standards in the rate studies according to the well-known hydrogen peroxide method (Owens et al., 1989). The rate of prochlorperazine degradation in solution under various light sources (254 nm UV light, diffuse light and sunlight) was studied. The light sources used abovF were quantified using potassium ferrioxalate as a chemical actinometer). The photodegradation rate was found to be greater in ampoules sealed under nitrogen than air, but the thermal degradation was faster in ampoules sealed with air than those purged with nitrogen. Amber ampoules retarded the rate of degradation under all photolytic conditions. This is a vital consideration for the packaging and storage of prochlorperazine in injectables. Degradation was found to occur mainly by first-order kinetics and the degradation rate decreased in the following order: sunlight » UV light 254 nm > fluorescent I diffuse light. Solid state samples, however, were found to be relatively stable to the various light / heat conditions over a 6 month period when compared to prochlorperazine solutions, but still considerably unstable. Thus both storage and packaging is a vital consideration for prochlorperazine injectables. The thermal behaviour of mixtures of prochlorperazine with standard excipients, was assessed for potential interactions, using differential scanning calorimetry. For most of the excipients (magnesium stearate, stearic acid, Explotab®, AC-Di-Sol®, Encompress® and Ludipress®, lactose and Starch 1500®) disappearance or broadening of the melting endotherm of the drug indicated interactions. Lubritab®, however, was the only 'inert' excipient tested. Liquid chromatography - mass spectrometry (LC-MS) was used to determine the nature of the degradation products. The major degradation pathways included dechlorination and demethylation of the parent drug, as well as sulfoxidation and Noxidation. Prochlorperazine underwent dechlorination and sulfoxidation with subsequent photosubstitution to yield the 2-hydroxy derivative. The solid state photostudies showed the formation of dealkylated, oxidised and hydroxylated products, sulfoxides and dimers. Since N-demethylation, N-oxidation, sulfoxidation and aromatic hydroxylation are reported to occur in the in vitro metabolism of perazine derivatives, it does appear that there is some relationship between metabolites and photoproducts (Breyer, 1974). This study has been successful in providing understanding of the photolytic and thermal degradation pathways of prochlorperazine.
- Full Text:
- Date Issued: 2000
- Authors: Antunes, Edith Martins
- Date: 2000
- Subjects: Phenothiazine
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4536 , http://hdl.handle.net/10962/d1016399
- Description: Prochlorperazine, a member of the piperazine subclass of phenothiazines, widely used as an anti-emetic, is susceptible to oxidation to sulfoxides. These are main metabolites and degradants of all phenothiazines which are found to be inactive at the dopamine receptors. Prochlorperazine causes photosensitivity effects in patients attributed to dechlorination at C2 with the release of HCI (Huang and Sands, 1967; Nejmeh and Pilpel, 1978; Moore and Tamat, 1980). The aim of this study is to investigate the thermal and photostability of prochlorperazine edisylate and mesylate salts in the solid state and in solution. Prochlorperazine is available as a fine chemical and in a variety of dosage forms, including injectables and tablets. According to ICH guidelines, any degradants greater than 0.1 % are required to be isolated and identified. In order to assess the photostability of the two salts, an HPLC method was developed and validated for linearity, accuracy and precision, selectivity, limit of detection, quantitation and ruggedness. Sulfoxides were synthesised for use as standards in the rate studies according to the well-known hydrogen peroxide method (Owens et al., 1989). The rate of prochlorperazine degradation in solution under various light sources (254 nm UV light, diffuse light and sunlight) was studied. The light sources used abovF were quantified using potassium ferrioxalate as a chemical actinometer). The photodegradation rate was found to be greater in ampoules sealed under nitrogen than air, but the thermal degradation was faster in ampoules sealed with air than those purged with nitrogen. Amber ampoules retarded the rate of degradation under all photolytic conditions. This is a vital consideration for the packaging and storage of prochlorperazine in injectables. Degradation was found to occur mainly by first-order kinetics and the degradation rate decreased in the following order: sunlight » UV light 254 nm > fluorescent I diffuse light. Solid state samples, however, were found to be relatively stable to the various light / heat conditions over a 6 month period when compared to prochlorperazine solutions, but still considerably unstable. Thus both storage and packaging is a vital consideration for prochlorperazine injectables. The thermal behaviour of mixtures of prochlorperazine with standard excipients, was assessed for potential interactions, using differential scanning calorimetry. For most of the excipients (magnesium stearate, stearic acid, Explotab®, AC-Di-Sol®, Encompress® and Ludipress®, lactose and Starch 1500®) disappearance or broadening of the melting endotherm of the drug indicated interactions. Lubritab®, however, was the only 'inert' excipient tested. Liquid chromatography - mass spectrometry (LC-MS) was used to determine the nature of the degradation products. The major degradation pathways included dechlorination and demethylation of the parent drug, as well as sulfoxidation and Noxidation. Prochlorperazine underwent dechlorination and sulfoxidation with subsequent photosubstitution to yield the 2-hydroxy derivative. The solid state photostudies showed the formation of dealkylated, oxidised and hydroxylated products, sulfoxides and dimers. Since N-demethylation, N-oxidation, sulfoxidation and aromatic hydroxylation are reported to occur in the in vitro metabolism of perazine derivatives, it does appear that there is some relationship between metabolites and photoproducts (Breyer, 1974). This study has been successful in providing understanding of the photolytic and thermal degradation pathways of prochlorperazine.
- Full Text:
- Date Issued: 2000
The Stockenström judgment, the Warren report and the Griqualand West rebellion, 1876-8
- Authors: White, Anthony Nevins
- Date: 1978
- Subjects: Warren, Charles, Sir, 1840-1927 , Griqualand West -- History , Land tenure -- Griqualand West , Griqua Rising, 1878 , Griqua (African people) -- History , Tlharo (African people) -- History , Tlhaping (African people) -- History , Baga-maidi (African people) -- History , Stockenström, Andries, 1844-1880 , Genealogy , Korana (African people) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2591 , http://hdl.handle.net/10962/d1007239 , Warren, Charles, Sir, 1840-1927 , Griqualand West -- History , Land tenure -- Griqualand West , Griqua Rising, 1878 , Griqua (African people) -- History , Tlharo (African people) -- History , Tlhaping (African people) -- History , Baga-maidi (African people) -- History , Stockenström, Andries, 1844-1880 , Genealogy , Korana (African people) -- History
- Description: From Preface: South African frontiers periodically provided the backdrop for conflict between Blacks and Whites over land, and, in this respect, Griqualand West proved no exception. The arrival of the trekboers in the 1830s heralded the beginning of the land problem in Griqualand West, and the situation worsened with the discovery of diamonds and the subsequent influx of land-hungry Whites. By the 1870s the stage was then set for a major clash between Blacks and Whites with land as the central focus. The Griqualand West Administration tried to rectify this situation in 1875 by setting up a Land Court under Judge Andries Stockenström. Stockenström's judgment was highly controversial, as many Griqua and Blacks lost land, although no land which had been claimed by a Griqua or Black was granted to a White. As Stockenström had not resolved the land problem, the Griqualand West authorities brought in Captain Charles Warren to settle the matter of land ownership in the Province. The Warren Report was considered by all concerned to be fair, but it did not prevent the outbreak of hostilities in 1878. The two main foci of this study are, then, land ownership and the Rebellion and the link, if any, between them. The main sources for the work have been the Griqualand West archive in the Cape Archives, for the period 1872-1880, and various newspapers. The Cape and Imperial Blue Books were useful sources, especially on the military history of the rebellion. Interviews conducted in Bophuthatswana and Griqualand West clarified many obscure points and raised others, most of which have been answered in this work. A considerable number of contemporary published works were also consulted, but, although most mentioned the land problem and the Rebellion, few contained anything worthy of mention, especially with regard to the military history of the Rebellion. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1978
- Authors: White, Anthony Nevins
- Date: 1978
- Subjects: Warren, Charles, Sir, 1840-1927 , Griqualand West -- History , Land tenure -- Griqualand West , Griqua Rising, 1878 , Griqua (African people) -- History , Tlharo (African people) -- History , Tlhaping (African people) -- History , Baga-maidi (African people) -- History , Stockenström, Andries, 1844-1880 , Genealogy , Korana (African people) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2591 , http://hdl.handle.net/10962/d1007239 , Warren, Charles, Sir, 1840-1927 , Griqualand West -- History , Land tenure -- Griqualand West , Griqua Rising, 1878 , Griqua (African people) -- History , Tlharo (African people) -- History , Tlhaping (African people) -- History , Baga-maidi (African people) -- History , Stockenström, Andries, 1844-1880 , Genealogy , Korana (African people) -- History
- Description: From Preface: South African frontiers periodically provided the backdrop for conflict between Blacks and Whites over land, and, in this respect, Griqualand West proved no exception. The arrival of the trekboers in the 1830s heralded the beginning of the land problem in Griqualand West, and the situation worsened with the discovery of diamonds and the subsequent influx of land-hungry Whites. By the 1870s the stage was then set for a major clash between Blacks and Whites with land as the central focus. The Griqualand West Administration tried to rectify this situation in 1875 by setting up a Land Court under Judge Andries Stockenström. Stockenström's judgment was highly controversial, as many Griqua and Blacks lost land, although no land which had been claimed by a Griqua or Black was granted to a White. As Stockenström had not resolved the land problem, the Griqualand West authorities brought in Captain Charles Warren to settle the matter of land ownership in the Province. The Warren Report was considered by all concerned to be fair, but it did not prevent the outbreak of hostilities in 1878. The two main foci of this study are, then, land ownership and the Rebellion and the link, if any, between them. The main sources for the work have been the Griqualand West archive in the Cape Archives, for the period 1872-1880, and various newspapers. The Cape and Imperial Blue Books were useful sources, especially on the military history of the rebellion. Interviews conducted in Bophuthatswana and Griqualand West clarified many obscure points and raised others, most of which have been answered in this work. A considerable number of contemporary published works were also consulted, but, although most mentioned the land problem and the Rebellion, few contained anything worthy of mention, especially with regard to the military history of the Rebellion. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1978
Some aspects of the chemistry of zirconium compounds relating to their combination with collagen
- Williams-Wynn, David Ernest Arthur
- Authors: Williams-Wynn, David Ernest Arthur
- Date: 1960
- Subjects: Zirconium compounds , Collagen
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4513 , http://hdl.handle.net/10962/d1013456
- Description: [Summary] Some properties of zirconium compounds in aqueous solution have been determined using physico-chemical techniques. Zirconium oxychloride was used as the source of zirconium in all detailed investigations; zirconium sulphate was used in a few cases for comparative purposes. The Stokes diaphragm cell method has been used to determine the diffusion coefficient of zirconium in hydrochloric acid solution. It was found that the diffusion coefficient fell progressively with time, a limiting value being reached 4 to 5 weeks after dissolving the salt, and it was demonstrated that particles in the aged solutions were more homogeneous than in freshly prepared solutions. The limiting values were concentration dependent; dilute solutions had a lower diffusion coefficient than the more concentrated solutions when measured at the natural pH. In the presence of added acid the rate of diffusion was increased until a limiting value was reached in 0.5 M acid. The addition of alkali or complexing acids reduced the rate of diffusion.
- Full Text:
- Date Issued: 1960
- Authors: Williams-Wynn, David Ernest Arthur
- Date: 1960
- Subjects: Zirconium compounds , Collagen
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4513 , http://hdl.handle.net/10962/d1013456
- Description: [Summary] Some properties of zirconium compounds in aqueous solution have been determined using physico-chemical techniques. Zirconium oxychloride was used as the source of zirconium in all detailed investigations; zirconium sulphate was used in a few cases for comparative purposes. The Stokes diaphragm cell method has been used to determine the diffusion coefficient of zirconium in hydrochloric acid solution. It was found that the diffusion coefficient fell progressively with time, a limiting value being reached 4 to 5 weeks after dissolving the salt, and it was demonstrated that particles in the aged solutions were more homogeneous than in freshly prepared solutions. The limiting values were concentration dependent; dilute solutions had a lower diffusion coefficient than the more concentrated solutions when measured at the natural pH. In the presence of added acid the rate of diffusion was increased until a limiting value was reached in 0.5 M acid. The addition of alkali or complexing acids reduced the rate of diffusion.
- Full Text:
- Date Issued: 1960
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