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The benefits of low UV dose treatment of horticultural produce – also known as hormetic treatment - have been attested to in numerous studies conducted over the last 15 years. However, commercial growers have not adopted the concept of hormesis. With increasingly stringent controls on the use of fungicides and other chemical agents the time has come to examine how hormetic treatment might be applied in the horticulture sector. The objectives of this work were firstly, to confirm UV-induced hormetic effects applied postharvest for a number of different types of produce, namely, tomatoes, broccoli, strawberries and mangoes. Secondly, to evaluate the use of rollers to ensure full surface treatment of produce, and thirdly to evaluate the possibility of treating produce preharvest. In order to investigate surface UV dose distributions, a polystyrene sphere (Diameter 70 mm) was used to simulate fruits such as tomatoes, apples, peaches etc., that have an approximately spherical form. Biodosimetry based on spores of Bacillus subtilis was employed to experimentally determine UV doses and to compare the results obtained with theoretical predictions. Good agreement was obtained and the modelling approach was extended to other types of produce. This showed the amenability of mechanical rollers to ensure full surface treatment of produce. Postharvest treatment of produce was carried using conventional low intensity UV sources principally emitting at 254 nm and also a commercially available high energy pulsed UV source. Treatment using the conventional UV source was carried out on mechanical rollers within a UV cabinet designed for this work at a fixed distance from the source and at an intensity of 1000 μW/cm2. A 5 minute conventional UV treatment of tomatoes was approximately comparable to fruit given a 3-pulsed treatment using the pulsed source (507 J/pulse of polychromatic light). The colour and texture of both groups of fruit were significantly maintained as compared with controls. The treated tomatoes also showed a significant increase in the ascorbic acid levels during storage. Similarly, a 15 minute conventional UV treatment of broccoli heads was comparable to heads given a 10-pulsed treatment using the pulsed source. Where both treatments gave rise to a statistically significant retention of green colour of treated broccoli. In addition, mangoes given a 10 minute conventional UV treatment were comparable to fruit given a 20-pulsed treatment using the pulsed source with both treatments leading to maintenance of texture as compared to control fruit. This confirmed the UV-hormetic effects. The effects of conventional and pulsed treatments are compared and discussed. Preharvest treatment of tomatoes and strawberries was carried out in commercial glasshouses. Doses of either 3 or 8 kJ/m2 were delivered to the fruits using a treatment device designed for the work, which delivered a combined intensity of 2000 μW/cm2 from two low pressure UV sources. The treated tomatoes showed a delay in development of colour as measured on the vine and after picking. Picked tomatoes were inoculated with P. digitatum and C. gloeosporioides and the results obtained showed a significant inhibition of the development of the fungi in the treated fruit during the storage period. These results suggest that the beneficial response shown by the preharvest treatment is not a localised one but a systematically induced resistance observable throughout the treated plant. This was shown by monitoring tomato fruits on treated plants which themselves where not directly exposed to the UV light. The two doses elicited different responses in the treated strawberries, with the 8 kJ/m2 dose causing the fruit to redden significantly faster than the 3 kJ/m2 treated fruits and controls. This could have significant nutritional benefit as the red colour of strawberries has been correlated with anthocyanin levels. On the other hand, treatment at the lower UV dose led to a lag in colour development. The amenability of the equipment utilised for commercial application is discussed.

In people with neuromotor deficits of trunk and lower extremities, maintaining and regaining balance is a difficult task. Many undergo rehabilitation to improve their movement capabilities, health, and overall interactions with their environment. Rehabilitation consists of a set of interventions designed to improve the individual’s mobility and independence. These strategies can be passive, active or task-specific and are dependent on the type of injury, how the individual progresses, and the intensity of the activity. Some of the common rehabilitation interventions to strengthen muscles and improve coordination are accomplished either by the manual assistance of a physical therapist, bodyweight suspension systems or through robotic-assisted training. There are several types of rehabilitation robotic systems and robotic control strategies.However, there are few robotic studies that compare their robotic device’s control strategy to common rehabilitation interventions. This dissertation introduces robotic strategies centered around rehabilitation ones and characterizes human motion in response to the robotic forces. Two cable-driven robotic systems are utilized to implement the robotic controllers for different tasks. Further details of the two cable-driven systems are discussed in Chapter 1. The validation and evaluation of these robotic strategies for standing rehabilitation is discussed in Chapter 2. A case study of a robotic training paradigm for individuals with spinal cord injury is presented in Chapter 3. Chapter 4 introduces a method to redistribute individuals’ weight using pelvic lateral forces. Chapter 5 and 6 characterizes how young and older groups respond to external perturbations during their sit-to-stand motion. This dissertation presents robotic strategies that can be implemented as rehabilitation interventions. It also presents how individuals’ biomechanics and muscle responses may change depending on the force control paradigm.These robotic strategies can be utilized by training individuals to improve their reactive and active balance control and thus reduce their risk of falling.

Thesis (MScMedSc)-- Stellenbosch University, 2014. / ENGLISH ABSTRACT: Diving medical doctors frequently make use of Hyperbaric Facilities without fully realising their legal and ethical responsibilities towards the safety of their patients and their staff. Few have specific training in the technical or operational aspects of these facilities; this deficiency is exacerbated when these are established in remote areas. The potential dangers are real and the results can be devastating. Most current regulatory, manufacturing, safety and operational guidance documents are not flexible enough to be applied universally, nor do they offer practical guidance on the recognition and the mitigation of the unique and relevant hazards at a given facility. The goal of integrated safety is rarely achieved. The Risk Assessment Guide (RAG) was developed by the investigator as a tool to qualify the actual safety status of a hyperbaric facility and to offer guidance on how to improve and maintain it. Although the RAG has been subject to extensive peer review and field implementation over the past 13 years, it has not been subject to scientific validation. Therefore, the objective of this thesis was to do so by (1) retrospectively reviewing the most common safety concerns affecting facility status as identified by the RAG; (2) using the data derived from the analysis to produce a predictive model of likely safety status for un-assessed facilities; and (3) consolidating the results in the form of specific recommendations to improve and maintain safety status. Data collected from a consistent application of the RAG over a period of 13 years, covering 105 applicable facilities, was analysed to determine the common safety concerns, particularly those affecting safety status by means of a consolidated Risk Assessment Score (RAS). The RAS values permitted comparisons between the facilities assessed. The various factors associated with a higher RAS were determined by means of a multivariate regression. Thereupon, the most significant determinant factors were built into a predictive model for the likely safety status of an un-assessed facility. Finally, the most common safety concerns were identified and summarised so that medical practitioners are empowered to determine, improve and maintain the safety status of a given facility. The conclusions of this project are that: (1) the RAG is an appropriate tool to assess facilities for risk elements relevant to their safety status while simultaneously filling the knowledge gaps to equip medical practitioners and staff to improve and maintain safety; (2) reliable predictions on unknown facilities can be made to provide medical practitioners with the necessary information on whether a given facility is appropriate for patient referral; and (3) the RAG is a suitable benchmark for determining hyperbaric facility safety; the review of its application has provided objective data that will permit the formulation of future safety guidelines based on empirical rather than arbitrary information. / AFRIKAANSE OPSOMMING: Duikmediese dokters maak dikwels gebruik van hiperbariese fasiliteite sonder om die wetlike en etiese verantwoordelikhede ten opsigte van die veiligheid van hul pasiënte en personeel te besef. Weinig het spesifieke opleiding in die tegniese of operasionele aspekte van hierdie fasiliteite; hierdie tekort is gewoonlik erger in afgeleë gebiede. Die potensiële gevare is wesenlik en die gevolge kan verwoestend wees. Meeste van die huidige regulatoriese-, vervaardigings-, veiligheids en operasionele leidingsdokumente is nie buigsaam genoeg om in die algemeen toegepas te kan word nie. Hulle bied ook nie praktiese leiding oor die erkenning en die versagting van unieke en relevante gevare by 'n gegewe fasiliteit nie. Die doelwit van geïntegreerde veiligheid word selde bereik. Die “Risk Asssessment Guide” (RAG) is voorheen deur die navorser ontwikkel as 'n instrument om die werklike veiligheidsstatus van 'n hiperbariese fasiliteit te kwantifiseer en leiding te bied oor hoe om dit te verbeter en in stand te hou. Alhoewel die RAG onderhewig was aan uitgebreide eweknie hersiening en praktiese uitvoering oor die afgelope 13 jaar, was dit nie voorheen onderhewig aan wetenskaplike validasie nie. Die doelwit van hierdie tesis is dus om hierdie te bewerkstellig deur (1) die mees algemene veiligheidskommernisse wat fasiliteitstatus beïnvloed, soos deur die RAG geïdentifiseer, retrospektiewelik te hersien; (2) die data wat deur die hersiening verkry is te gebruik om 'n model te ontwikkel vir onbeoordeelde fasiliteite, wat die waarskynlike veiligheidsstatus kan voorspel, en (3) die resultate te konsolideer in die vorm van spesifieke aanbevelings om veiligheidsstatus te verbeter en in stand te hou. Die data wat ingesamel is deur die konsekwente toepassing van die RAG oor 'n tydperk van 13 jaar en wat 105 fasiliteite gedek het, is ontleed om die algemene veiligheidskommernisse, veral die wat die veiligheidsstatus beïnvloed, deur middel van 'n gekonsolideerde Risikoassesserings waarde (RAW) te bepaal. Die duidelike en aangepaste RAW laat toe om vergelykings tussen die fasiliteite te tref. Faktore wat verband hou met 'n hoër RAW was deur middel van 'n meervoudige regressie bepaal. Daarna is die belangrikste determinante in 'n voorspellende model gebou om die waarskynlike veiligheidsstatus van 'n onbeoordeelde fasiliteit te bepaal. Ten slotte was die mees algemene veiligheidskommernisse geïdentifiseer en opgesom om sodoende mediese praktisyns te bemagtig om die veiligheidsstatus van 'n gegewe fasiliteit vas te stel, te verbeter en in stand te hou. Die gevolgtrekkings van hierdie projek is dat: (1) die RAG 'n geskikte instrument is om fasiliteite te evalueer vir risiko-elemente wat relevant is tot hul eie veiligheidsstatus en terselfdertyd die kennisgapings te vul om geneeshere en personeel toe te rus om veiligheid te verbeter en in stand te hou; (2) redelik betroubare voorspellings oor onbekende fasiliteite kan gemaak word om vir mediese praktisyns die nodige inligting te verskaf aangaande die geskiktheid van 'n gegewe fasiliteit vir pasiënt-verwysing, en (3) dat die RAG 'n geskikte maatstaf is vir die bepaling van hiperbariese fasiliteit veiligheid. Die hersiening van die toepassing het objektiewe data voorsien wat die formulering van toekomstige veiligheidsriglyne, geskoei op empiriese eerder as arbitrêre inligting, sal toelaat.

Made available in DSpace on 2014-08-20T13:44:42Z (GMT). No. of bitstreams: 1 dissertacao_marcos_paulo_ludwig.pdf: 377282 bytes, checksum: eeea4d92a3337e0a6a5b8f998da4e6d7 (MD5) Previous issue date: 2009-03-20 / The objective of this paper was to evaluate seed coating of soybean seed using equipment for treatment with spray system Grazmec®. The treatments applied with the equipment were: 1) control, 2) fungicide, 3) amino acid, 4) polymer, 5) fungicide + amino acid, 6) fungicide + insecticide, 7) fungicide + polymer, 8) fungicide + insecticide + polymer, 9) fungicide + amino acid + insecticide. The evaluation of the spray system was followed by moisture content determination, weight of 1000 seeds and coverage. Also field emergence was evaluated. The seed quality evaluations were followed by germination, vigor, dry matter of plants and seed health. The seeds were storage for six months and evaluations were done every 60 days. The results shows that soybean seed moisture content was 1% lower with the treatment; the field emergence and weight of 1000 seeds were no affected by treatment; when the change of product and/or seed the equipment should regulated for a coating good. The applied of polymer improve seed coating. The application of amino acid isolate improve the performance of the seeds; the use of amino acid combined with fungicide, insecticide and polymer do not improve the seed quality; the use of polymer fungicide + insecticide + polymer improve leaf area, dry mass of root and of part aerial of the plant compare with control in storage seed for four months after treatment. / Com o objetivo de avaliar o tratamento e o recobrimento de sementes de soja em um equipamento com sistema de aspersão da marca Grazmec Spray System® foi realizado um conjunto de experimentos na Faculdade de Agronomia Eliseu Maciel (FAEM) da Universidade Federal de Pelotas, campus do Capão do Leão. Os tratamentos aplicados com o equipamento foram: 1) testemunha, 2) fungicida, 3) aminoácido, 4) polímero, 5) fungicida + aminoácido, 6) fungicida + inseticida, 7) fungicida + polímero, 8) fungicida + inseticida + polímero e 9) fungicida + aminoácido + inseticida. Para avaliar o sistema de aspersão foi realizada a avaliações de grau de umidade, emergência em campo, peso de 1000 sementes e cobertura das sementes. Para a determinação da eficiência dos tratamentos foram realizadas avaliações de germinação, vigor, massa seca de plantas, desempenho inicial de plantas e sanidade de sementes. Após tratadas, as sementes foram armazenadas por seis meses e avaliadas a cada 60 dias. Os resultados demonstraram que o aumento no grau de umidade das sementes de soja tratadas e/ou recobertas com o equipamento de sistema de aspersão foi inferior a 1%. A emergência de plântulas e o peso de 1000 sementes não foram afetados pelo tratamento e/ou recobrimento realizado com o sistema de aspersão. Para que o recobrimento seja eficaz o equipamento deve ser regulado a cada mudança de produto e/ou semente. O uso de polímero melhora o recobrimento das sementes. A aplicação do aminoácido isolado melhora a germinação das sementes. A combinação de aminoácido com fungicida, inseticida e polímero não melhora o desempenho das sementes. A aplicação de fungicida + inseticida + polímero aumenta a área foliar, massa seca de raiz e de parte aérea das plantas quando comparada com a sem tratamento em sementes armazenadas por 4 meses após o tratamento.