ABSTRACT Alliaria petiolata (garlic mustard) is an aggressive non-native and invasive forb that negatively impacts native arbuscular mycorrhizal communities and inhibits or prevents the growth of native plant species. Invasive species mitigation and management strategies that use native revegetation vary in success. This study focuses on which species naturally regenerate in areas where A. petiolata has been mitigated to help inform restoration efforts. Seedling emergence of species within the seed bank of four plot types (uninvaded, invaded, chemically treated, and mechanically treated) were observed two years post restoration efforts to determine which native species are likely to persist to seedlings following management. Species abundance and percent cover of all plant species were recorded to evaluate the presence of species in addition to plant health and physiological differences. Native species abundance was significantly reduced within herbicide treated plots as compared to untreated and invaded plots (p=0.02). Plots treated with mechanical removal had the greatest percent cover of native plants as compared to all other plot types but were dominated by colonizing species which is typical of a disturbed habitat. Mechanical removal also resulted in a greater abundance and stability among functional groups of native species, than those treated with herbicide. Forb species dominated coverage of plots over other functional groups when treated with herbicide. Alliaria petiolata invasion and management methods significantly impacted forb and graminoid species, as they had significantly lower abundance in plots treated with herbicide. The results demonstrate that the method of removal as well as the presence of A. petiolata affects emergence of plant species from the seedbank. The additional disturbance of mechanical removal may alter successional trajectories following invasion. Herbicide treatment resulted in the most similar species abundance as the uninvaded reference plots, which had the lowest seedling emergence and percent cover.

Objectif : La dentisterie pédiatrique évolue vers des approches minimalement invasives pour la gestion des caries, transition accentuée par l'impact de la pandémie de la COVID-19. Parmi les procédures préconisées en dentition primaire, la technique de Hall s'est montrée efficace pour relever des défis tels que la coopération limitée des jeunes patients et l'accès restreint aux blocs opératoires. Malgré son efficacité avérée de 98%, son adoption demeure limitée parmi les dentistes pédiatriques. Le but de cette étude était d'évaluer l'enseignement de la technique de Hall dans les programmes de spécialité en dentisterie pédiatrique, d'analyser son utilisation, sa connaissance, et sa perception parmi les spécialistes américains et canadiens, ainsi que d'explorer les obstacles limitant son adoption. Méthodologie : Les dentistes pédiatriques du Canada et des États-Unis ont été sollicités à travers la liste de diffusion de l'American Academy of Pediatric Dentistry. Un questionnaire composé de 32 énoncés et d’une section spécifique destinée aux directeurs de programme a été distribué électroniquement en septembre (États-Unis) et en octobre (Canada) 2023, via la plateforme LimeSurvey. Des rappels ont été faits après 4 à 6 semaines. Résultats : Au sein de l'échantillon de 364 participants, l'analyse statistique a révélé des différences significatives dans l'utilisation de la technique en fonction de la région d'exercice (p=0,009), du type de pratique (p<0,001), de l'âge du professionnel (p<0,001), du nombre d'années d'expérience (p<0,001), des sources de remboursement (p=0,003) et si la technique leur avait été enseignée ou non (p<0,001). Conclusion : Les résultats indiquent une augmentation de l'utilisation de la technique de Hall parmi les dentistes pédiatriques, tout en soulignant la persistance d'obstacles. Ils proposent aussi des pistes d'intervention pour encourager davantage son adoption, en cohérence avec l'évolution vers des approches minimalement invasives de gestion de la carie. / Introduction: Pediatric dentistry increasingly favors minimally invasive approaches, discouraging extensive treatments such as complete caries removal. The COVID-19 pandemic hastened this shift, highlighting relevance of procedures like the Hall technique (HT) for managing carious lesions in primary dentition while addressing challenges such as patient cooperation and restricted access to operating rooms. Despite being recognized for its 98% efficacy, this technique continues to encounter limited adoption among pediatric dentists. Purpose: To assess the integration and teaching methods of the HT in graduate pediatric dentistry programs, evaluate its utilization, comprehension, and perception among American and Canadian specialists, and explore obstacles to its adoption. Methods: Pediatric dentists in Canada and United States (U.S.) were surveyed via the American Academy of Pediatric Dentistry mailing list, featuring a dedicated section for program directors. Using the LimeSurvey platform, a questionnaire of 32 potential inquiries was electronically available in early September (U.S.) and early October (Canada) of 2023, with reminders issued 4-6 weeks later. Results: Of 364 participants, statistical analysis indicated significant differences in HT use according to practice regions (p=0.009), settings (p<0.001), age (p<0.001), years of experience (p<0.001), reimbursement sources (p=0.003), and education exposure (p<0.001). This offers a comprehensive understanding of the nuanced landscape surrounding the HT among pediatric dentists in Canada and the U.S. Conclusion: This investigation reveals a growing acceptance of the HT, despite persistent challenges faced by pediatric dentists in Canada and the U.S. These findings provide actionable insights for improving the adoption of the HT in contemporary pediatric dentistry practices, aligning with today's emphasis on minimally invasive approaches.

Borderline personality disorder (BPD) is debilitating mental disorder that affects approximately 2 percent of individuals in community samples. Despite advances in psychiatry, a lack of clear guidance for diagnosis and treatment hinders the pursuit of appropriate treatments and a comprehensive understanding of this mental disorder. Transcranial direct current stimulation is a novel therapeutic tool that has shown positive outcome amongst different psychiatric illnesses. Concerning BPD, with the complexity of diagnosis and the lack of targeted-symptom treatments, data is limited and scarce. Although the available data is limited, with only five published articles, these studies have demonstrated positive outcomes in patients with BPD. However, discrepancies among trials have impeded further comparisons and clear recommendations. Therefore, the research team at Montreal Mental Health University Institute (IUSMM) launched a pilot study to examine the feasibility of tDCS on BPD. In doing so, we also aim to examine the effects of tDCS on some of BPD symptoms. Results revealed that acceptance of tDCS among BPD has a recruitment rate of 68 % and drop off rate of 23% with minimum temporary adverse effects. The effect of tDCS on BPD has shown increased impulsivity whereas improved mood post tDCS. Long term tDCS effects conjugated with psychotherapy revealed overall improvement in BPD psychopathology on BPDSI. To sum up, this study showed that tDCS is a feasible therapeutic tool for patients with BPD. The heightened impulsivity in the presence of alleviation (improvement) of other BPD psychopathologies urge us to initiate standardized protocols. This would help initiating accurate parameters and building a deeper understanding of some common symptoms of BPD. / Le trouble de la personnalité limite (TPL) concernerait environ 2 % de la populaHon générale. Même si la recherche clinique a largement progressé sur les dernières décennies, les psychothérapies spécialisées soutenues par ces dernières restent parHellement accessibles, acceptables et d’efficacité modérée. Ainsi, le développement de nouvelles formes thérapeuHques reste d’actualité. Par ailleurs, la sHmulaHon transcrânienne à courant conHnu (StCC) est un nouvel ouHl thérapeuHque qui a montré des résultats posiHfs dans diverses maladies psychiatriques. En ce qui concerne le TPL, les données demeurent limitées, avec seulement cinq études contrôlées publiées sur le sujet. Alors qu’elles sont encourageantes, notamment sur l’impulsivité, les divergences entre les essais limitent la possibilité de conclusions fermes. Ainsi, dans ce\e étude, nous évaluons la faisabilité et l’efficacité de la StCC pour traiter l'impulsivité chez les personnes a\eintes de TPL. Nous avons recruté 41 paHents sur une période de 10 mois. Le taux de recrutement de la StCC chez les paHents vivant avec un TPL à qui l’étude a été proposée est de 68 % et le taux d'abandon après recrutement de 23 %. Les effets indésirables sont temporaires et minimes. En pré-post StCC, « impulsivité » (score total UPPS) a augmenté, tandis que l'humeur dépressive (MADRS) a diminué. À 3 mois l’associaHon de la StCC et de la psychothérapie est associée à une diminuHon globale de l’intensité du TPL (BPDSI). En conclusion, ce\e étude souHent la faisabilité de l’approche de StCC pour les paHents a\eints de TPL. Si globalement, l’humeur est améliorée avec la StCC et l’intensité du TPL avec la combinaison, l'augmentaHon de l'impulsivité quesHonne les paramètres de sHmulaHon des futures études.

Obturation par système de ligature thermo-fusion de l'artère pulmonaire dans les lobectomies par vidéothoracoscopie. Objectifs : La résection pulmonaire anatomique est la stratégie de traitement principale pour les cancers du poumon non à petites cellules (CPNPC) de stade I et II. L’approche minimalement invasive est recommandée par rapport à l’approche ouverte par thoracotomie. La division de l'artère pulmonaire est généralement effectuée à l'aide d'agrafes mécaniques. Cependant, leur taille, leur rigidité et leur forme peuvent les rendre difficiles à utiliser sur les petites branches de l’artère pulmonaire, ce qui peut augmenter le risque d'hémorragie. Les appareils de ligature thermo-fusion peuvent constituer une alternative pour sceller les branches de l’artère pulmonaire avec l'avantage d'être plus petits et plus fins. Cette thèse vise à évaluer l'efficacité et la sécurité d'un appareil à énergie ultrasonique pour sceller les branches de l’artère pulmonaire de 7 mm ou moins durant les résections pulmonaires anatomiques minimalement invasives. Méthodes : Une approche par étape a été adoptée. Initialement, une étude de survie animale a été menée. L’appareil à énergie ultrasonique a été utilisé pour diviser toutes les branches de l’artère pulmonaire lors de lobectomies par thoracoscopie. Deux essais cliniques de phase 1 ont été menés ; le premier lors de lobectomies ouvertes et le second lors de lobectomies par thoracoscopie. Dans les deux essais, l’appareil à énergie ultrasonique a été utilisé pour sceller les branches de l’artère pulmonaire de 7 mm ou moins. Un essai clinique multicentrique de phase 2 a enrôlé des patients devant recevoir une lobectomie par thoracoscopie. De manière similaire aux essais de phase 1, l’appareil à énergie ultrasonique a été utilisé pour sceller les branches de l’artère pulmonaire de 7 mm ou moins. Enfin, une étude animale évaluant la production de chaleur lors du scellement de l’artère pulmonaire avec des dispositifs à énergie a été réalisée. Résultats : Dans l'étude de survie animale, 21 branches de l’artère pulmonaire ont été scellées avec l’appareil à énergie ultrasonique. Une branche de 10 mm n’était pas complètement scellée immédiatement après l’application de l’appareil à énergie ultrasonique et a correctement été scellée en réappliquant l’appareil. Il n'y a eu aucune autre complication. Dans les essais cliniques de phase 1 et 2, un total de 180 patients ont été recrutés et 239 branches de l’artère pulmonaire ont été scellées avec l’appareil à énergie ultrasonique. Trois artères n’étaient pas complètement scellées en intraopératoire et un patient a nécessité une conversion en thoracotomie. Il n'y a eu aucune mortalité postopératoire. L'étude animale évaluant la production de chaleur émise par les appareils de ligature thermo-fusion a établi que l’appareil devrait avoir une marge de sécurité de 3 mm par rapport aux structures vitales. Conclusion : Dans cette approche par étapes, l’appareil à énergie ultrasonique était sécuritaire et efficace pour sceller les branches de l'artère pulmonaire de 7 mm ou moins. L’appareil est une alternative appropriée aux agrafes mécaniques pour sceller les petites branches de l'artère pulmonaire lors de résections pulmonaires anatomiques minimalement invasives. Cela pourrait rendre les résections pulmonaires minimalement invasives plus faciles et plus sécuritaires. / Ultrasonic Energy for Pulmonary Artery Branch Ligation During VATS Lobectomy Objectives : Anatomic lung resection is the primary treatment strategy for stage I and II non-small cell lung cancer (NSCLC). A minimally invasive approach is recommended over open thoracotomy. Pulmonary artery (PA) division is usually achieved with endostaplers. However, their large size, rigidity and shape can make them difficult to apply on small PA branches and may increase the risk of PA injury and hemorrhage. Ultrasonic energy devices may represent a suitable alternative for PA sealing with the advantage of being smaller and finer. This thesis aims at evaluating the safety and efficacy of an ultrasonic energy device to seal PA branches of 7 mm or less during minimally invasive anatomical lung resections. Methods : A stepwise approach was adopted. Initially, an animal survival study was conducted. The ultrasonic energy device was used to divide all the PA branches during video-assisted thoracoscopic surgery (VATS) lobectomy in the animals. Two phase 1 trials were conducted; the first was in open lobectomy and the second in VATS lobectomy. In both trials, the ultrasonic energy device was used to seal PA branches of 7 mm or less. A multicenter phase 2 clinical trial enrolled patients undergoing VATS lobectomy. Similarly to the phase 1 trials, the ultrasonic energy device was used to seal PA branches of 7 mm or less. Finally, an animal study evaluating heat production during PA sealing with energy devices was completed. Results : In the animal survival study, a total of 21 PA branches were sealed with the ultrasonic energy device. One 10 mm PA branch had a partial seal failure immediately at the time of sealing and was successfully sealed by reapplying the device. There were no other complications. In the phase 1 and 2 trials, a total of 180 patients were recruited and 239 PA branches were sealed with the ultrasonic energy device. Three intraoperative seal failures occurred, and one patient required conversion to thoracotomy. There was no postoperative mortality. The animal study evaluating heat production established that the device tip should have a safety margin of 3 mm from vital structures. Conclusions : In this bench-to-bedside approach, the ultrasonic energy device for sealing PA branches of 7 mm or less was safe and efficient. The device is a suitable alternative to endostaplers for sealing small PA branches during minimally invasive anatomical lung resections. This has the potential to make minimally invasive lung resections easier and safer.

Doctor of Philosophy / Department of Biology / Keith B. Gido / Many native freshwater animals are imperiled as a result of habitat alteration, species introductions and climate-moderated changes in disturbance regimes. Native conservation and nonnative species management could benefit from greater understanding of critical factors promoting or inhibiting native and nonnative success in the absence of human-caused ecosystem change. The objectives of this dissertation were to (1) explain spatiotemporal patterns of native and nonnative success, (2) describe native and nonnative response to uncharacteristic wildfire disturbance, and (3) test the hypothesis that wildfire disturbance has differential effects on native and nonnative species. This research was conducted across six sites in three reaches (tributary, canyon, and valley) of the unfragmented and largely-unmodified upper Gila River Basin of southwestern New Mexico. Secondary production was measured to quantify success of native and nonnative fishes prior to wildfires during 2008-2011. Native fish production was greater than nonnatives across a range of environmental conditions, although nonnative fish, tadpole, and crayfish production could approach or exceed that of native macroinvertebrates and fishes in canyon habitats, a warmwater tributary, or in valley sites, respectively. The second objective was accomplished by measuring biomass changes of a warmwater native and nonnative community during 2010-2013 before and after consecutive, uncharacteristic wildfires. Several native insect and fish taxa decreased after both wildfires, whereas nonnative decreases were most pronounced for salmonids and more limited for other taxa. Finally, effects of uncharacteristic wildfires followed by extreme flooding on metapopulations of native and nonnative fishes were contrasted during 2008-2013. Wildfire and flood disturbances increased extinction probabilities of all native fishes while leaving many nonnative fishes unaffected. These findings revealed a swinging pendulum of native and nonnative success, wherein wildfire disturbance resulted in a pendulum swing in favor of nonnatives. Ensuring the pendulum swings back in favor of natives will be facilitated by management activities that decrease wildfire size and intensity and maintain inherent ecosystem resilience.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The monitoring of patients in healthcare is of prime importance to ensure their efficient treatment. The monitoring of blood oxygen saturation in tissues affected by diseases or conditions that may negatively affect the function is a field that has grown in importance in recent times. This study involved the development and testing of a highly sensitive noninvasive blood oxygen saturation device. The device can be used to continuously monitor the condition of tissue affected by diseases which affect the blood flow through the tissue, and the oxygen usage in tissue. The device’s system was designed to specifically monitor occluded tissue which has low oxygen saturations and low perfusion. With the use of the device, it is possible to monitor the status of tissue affected by diseases such as meningococcemia and diabetes mellitus or conditions such as the recovery after plastic surgery. The study delved into all aspects involved in the development of a non-invasive artificial pulse oximeter, including but not limited to that of a detailed device design, signals analysis, animal in-vivo and laboratory in-vitro system design for the calibration of the system as well as human clinical validation and testing procedures. All these aspects were compared to determine the relative accuracies of the different models. Through testing it was shown that it is possible to non-invasively measure the mixed oxygen saturation in occluded tissue. However, without accurate validation techniques and methods of obtaining both arterial and venous blood samples in occluded tissue the system could not be fully validated for determining both the arterial and venous oxygen saturations in the human invivo study. Although the system was unable to accurately measure specifically the venous oxygenation it was able to measure the mixed oxygen saturation. With further research it would be possible to validate the system for measuring both the arterial and venous oxygen saturations. / AFRIKAANSE OPSOMMING: Die monitering van pasiënte in gesondheidsorg is van uiterste belang om doeltreffende behandeling te verseker. Die monitering van bloedsuurstofversadiging in weefsels wat geaffekteer word deur siektes of toestande wat ’n negatiewe impak kan hê op die funksie daarvan is ’n gebied wat aansienlike groei getoon het in die onlangse verlede. Die studie het die ontwikkeling en toetsing van ’n hoogs sensitiewe nieindringende bloedsuurstofversadigingsensor ingesluit. Hierdie sensor kan gebruik word om deurentyd die toestand van weefsel te monitor wat geaffekteer word deur siektes wat bloedvloei deur weefsel affekteer sowel as die suurstofgebruik in die weefsel. Die stelsel is ontwerp om spesifiek die ingeslote weefsel wat lae suurstofversadiging en lae perfusie het, te monitor. Deur gebruik te maak van die toestel is dit moontlik om die toestand van die weefsel wat geaffekteer word deur siektes soos meningococcemia en diabetes mellitus of toestande soos die herstel na plastiese sjirurgie te monitor. Die studie het gekyk na alle aspekte wat betrokke is in die ontwikkeling van ’n nie-indringende kunsmatige pols-oksimeter, insluitend maar nie beperk tot gedetailleerde ontwerp nie, sein analise, dier in-vivo en laboratorium in-vitro stelselontwerp vir die kalibrasie van die stelsel sowel as menslike kliniese bekragtiging en toetsprosedures. Al hierdie aspekte is vergelyk om die relatiewe akkuraatheid van die verskillende modelle te bepaal. Die toetse het gewys dat dit moontlik is om nie-indringend die gemengde suurstofversadiging in weefsel te bepaal. Sonder akkurate bekragtigingstegnieke en metodes om beide arteriële en vene bloedmonsters te versamel in ingeslote weefsel kan die stesel nie ten volle bekragtig word om beide arteriële- en veneversadigings in menslike in-vivo studie te bepaal nie. Hoewel die stelsel nie ’n akkurate meting van die aarsuurstof kon kry nie, is daar wel ’n akkurate meting geneem van die gemengde suurstofversadiging. Toekomstige navorsing kan lei tot die bekragtiging van die stelsel om beide arteriële en slagaar suurstofversadigings te meet.

Thesis (MScEng)--Stellenbosch University, 2009. / ENGLISH ABSTRACT: Minimal invasive surgery (MIS) enables surgeons to operate through a few small incisions made in the patient’s body. Through these incisions, long rigid instruments are inserted into the body and manipulated to perform the necessary surgical tasks. Conventional instruments, however, are constrained by having only five degrees of freedom (DOF), as well as having scaled and mirrored movements, thereby limiting the surgeon’s dexterity. Surgeons are also deprived of depth perception and hand-eye coordination due to only having two-dimensional visual feedback. Surgical robotics attempt to alleviate these drawbacks by increasing dexterity, eliminating the fulcrum effect and providing the surgeon with three-dimensional visualisation. This reduces the risks to the patient as well as to the surgeon. However, existing MIS systems are extremely expensive and bulky in operating rooms, preventing their more widespread adoption. In this thesis, a new, inexpensive seven-DOF primary slave manipulator (PSM) is presented. The four-DOF wrist is actuated through a tendon mechanism driven by five 12 VDC motors. A repeatability study on the wrist’s joint position was done and showed a standard deviation of 0.38 degrees. A strength test was also done and demonstrated that the manipulator is able to resist a 10 N opposing tip force and is capable of a theoretical gripping force of 15 N. / AFRIKAANSE OPSOMMING: Minimale indringende chirurgie (MIC) maak dit vir chirurge moontlik om operasies uit te voer deur ’n paar klein insnydings wat op die pasiënt se liggaam gemaak word. Deur hierdie insnydings word lang onbuigsame instrumente in die liggaam ingesit en gemanipuleer om die nodige chirurgiese take uit te voer. Konvensionele instrumente is egter beperk vanweë die feit dat hulle net vyf vryheidsgrade het, asook afgeskaalde bewegings en spieëlbewegings, en gevolglik die chirurg se handvaardigheid beperk. Chirurge word ook ontneem van dieptewaarneming en hand-oog-koördinasie, want hulle is beperk tot tweedimensionele visuele terugvoer. Chirurgiese robotika poog om hierdie nadele aan te spreek deur handvaardigheid te vermeerder, die hefboomeffek uit te skakel en die chirurg driedimensionele visualisering te bied. Dit verminder die risiko’s vir die pasiënt én vir die chirurg. Bestaande MIC-stelsels is egter uiters duur en neem baie plek op in teaters, wat verhoed dat hulle op ’n groter skaal gebruik word. In hierdie tesis word ’n nuwe, goedkoop sewevryheidsgrade- primêre slaafmanipuleerder (PSM) voorgelê. Die viervryheidsgrade-pols word beweeg deur ’n tendonmeganisme wat aangedryf word deur vyf 12 VDC-motors. ’n Herhaalbaarheidstudie is op die pols se gewrigsposisie gedoen, wat ’n standaardafwyking van 0.38 grade aangetoon het. ’n Sterktetoets is ook gedoen en het gewys dat die manipuleerder in staat is om ’n 10 N-teenkantelkrag te weerstaan en dat dit oor ’n teoretiese greepsterkte van 15 N beskik.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Minimally Invasive Surgery (MIS) in human beings is performed by making small incisions in the abdominal region of the patient and inflating the abdominal cavity with CO2. This procedure enables the surgeon to manipulate long rigid surgical instruments inside the patient in order to perform the surgery. Unfortunately the current methods of insertion and assembly of MIS instruments limit the surgeon to only five (of a possible seven) Degrees of Freedom (DOF). Along with this, the surgeon’s movements are mirrored (called the Fulcrum effect) and scaled around the point of incision. Minimally invasive surgical robots attempt to alleviate these drawbacks by eliminating the Fulcrum effect, as well as improving dexterity and accuracy. These robots’ abilities to improve the surgeon’s hand-eye coordination, enables the surgeon to perform surgeries using their natural movements with reduced fatigue. As a result of this, the risk to both patient and surgeon is reduced. Existing MIS robotic systems are extremely expensive and large, and as a result they are not widely used. In this thesis a new, lower cost, seven DOF robotic manipulator is further developed. The thesis focuses on the external three DOF Secondary Slave Manipulator (SSM) and combines it with the Primary Slave Manipulator (PSM) that was developed by a previous Masters student. Tests done on the SSM showed that the manipulator has a minimum resolution of 0.7 ± 0.2 mm (mean ± standard deviation) on the shoulder joint’s yaw rotation and 0.5 ± 0.2 mm in pitch rotation. The linear actuator used for insertion has a minimum resolution of 0.2 ± 0.2 mm. A strength test was also conducted and showed that the manipulator is easily capable of producing a 10 N actuation force as required during Minimally Invasive Robotic Surgery (MIRS) procedures. In conclusion the complete system has potential as a viable alternative to the existing systems due to its accuracy and lower cost. Future work will include the development of a user interface and control system for the complete robot. / AFRIKAANSE OPSOMMING: Minimaal Indringende Chirurgie (MIC) op mense word uitgevoer deur klein insnydings in die pasiënt se buik te maak en dan die abdominale holte met CO2 te vul. Dit stel die chirurg in staat om lang, onbuigbare instrumente binne die pasiënt te manipuleer om sodoende die operasie uit te voer. Die manier waarop die MIC instrument ontwerp is en die pasiënt binnegaan, laat egter slegs vyf vryheidsgrade toe, terwyl die chirurg self sewe vryheidsgrade in sy handbewegings het. Verder veroorsaak hierdie instrumente ook dat die chirurg se aksies in spieëlbeeld vertolk word (Fulcrum effek) en geskaleer is. Chirurgiese robotika poog om hierdie nadele teen te werk deur die Fulcrum effek te verwyder, en ook om handvaardigheid en akkuraatheid te bevorder. Die robot se potensiaal om die chirurg se hand-oog koӧrdinasie te verbeter, maak dit moontlik vir die chirurg om op ’n meer natuurlike en gemaklike manier te werk te gaan en bring minder vermoeienis mee. Dit verminder die risiko’s vir beide die pasiënt en die chirurg. Bestaande robotiese stelsels is egter baie duur en groot, en word dus nie meer algemeen gebruik nie. In hierdie tesis word ‘n nuwe sewe-vryheidsgraad robotiese manipuleerder ontwikkel. Die tesis fokus op die eksterne drie-vryheidsgraad Sekondêre Slaaf Manipuleerder (SSM) en kombineer dit met die Primêre Slaaf Manipuleerder (PSM) wat deur ʼn vorige Meestersstudent ontwikkel is. Toetse wat uitgevoer is op die SSM het getoon dat dit ’n minimum resolusie van 0.7 ± 0.2 mm (gemiddeld ± standaard afwyking) op die skouer se afwyking en 0.5 ± 0.2 mm om die onderskeie skouer aslyne toon. Die linieêre aktueerder wat vir inlassing gebruik word het ’n minimum resolusie van 0.2 ± 0.2 mm. ’n Sterktetoets is uitgevoer en het getoon dat die manipuleerder maklik die nodige 10 N krag soos benodig in Minimaal Indringende Robotiese Chirurgie (MIRC) prosedures kan lewer. Ter afsluiting, die volledige stelsel het die potensiaal as lewensvatbare alternatief tot die bestaande stelsels vanweë die akkuraatheid en laer koste verbonde. Toekomstige navorsing kan moontlik die ontwikkeling van ʼn gebruikerkoppelvlak en beheerstelsel vir die volledige robot insluit.

Objectives: The aims of this study are to answer the following questions (1) How does the pain intensity of lumbar and cervical disc surgery patients change within a postoperative time frame of 5 years? (2) Which sociodemographic, medical, work-related, and psychological factors are associated with postoperative pain in lumbar and cervical disc surgery patients? Methods: The baseline survey (T0; n = 534) was conducted 3.6 days (SD 2.48) post-surgery in the form of face-to-face interviews. The follow-up interviews were conducted 3 months (T1; n = 486 patients), 9 months (T2; n = 457), 15 months (T3; n = 438), and 5 years (T4; n = 404) post-surgery. Pain intensity was measured on a numeric rating-scale (NRS 0–100). Estimated changes to and influences on postoperative pain by random effects were accounted by regression models. Results: Average pain decreased continuously over time in patients with lumbar herniated disc (Wald Chi² = 25.97, p<0.001). In patients with cervical herniated disc a reduction of pain was observed, albeit not significant (Chi² = 7.02, p = 0.135). Two predictors were associated with postoperative pain in lumbar and cervical disc surgery patients: the subjective prognosis of gainful employment (p<0.001) and depression (p<0.001). Conclusion: In the majority of disc surgery patients, a long-term reduction of pain was observed. Cervical surgery patients seemed to benefit less from surgery than the lumbar surgery patients. A negative subjective prognosis of gainful employment and stronger depressive symptoms were associated with postoperative pain. The findings may promote multimodal rehabilitation concepts including psychological and work-related support.

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Invasive alien plant species have devastating effects on the environments that they invade. Australian Acacias, a group of plants that has been planted globally for a range of uses, but has escape plantation areas and became invasive in many countries, are particularly problematic. Acacia mearnsii is one of these invasive alien plant species and in South Africa it is also an important forestry species. It is currently the fifth most widespread invasive alien plant in South Africa, only restricted by the very arid Karoo, thus it is important to assess the different habitats that it enters. The Afromontane forest complex in South Africa is highly fragmented and is one of the most threatened Biomes in the country. The widespread forest margin tree Virgilia divaricata occurs within these forest margins. It is ecologically similar to A. mearnsii as these two species share many characteristics (nodulating legumes, forest pioneer species, fast growing and fire adapted). These species occur sympatrically within invaded forest margins and within these sites, there is a potential for biological exchanges of associated pests and pathogens in the form of arthropods and fungal species. We hypothesize that these two species have different interactions with their pests and pathogens in accordance with the Enemy Release Hypothesis (ERH) and the Biotic Resistance Hypothesis (BRH), respectively. We first compared arthropod associates between these two tree species and found that they share many arthropod species. The native tree did, however, have much higher abundances of herbivores and overall arthropod associates than the invasive tree species, which supports the predictions of the ERH. The distribution of these two species also had an effect on their arthropod assemblages. We assessed their ophiostomatoid fungal associates and herbivore loads and then determined how these pests and pathogens were influenced by environmental conditions along a water gradient. We also compared the effect of plant nutrient content of the two tree species on pest and pathogen loads. A. mearnsii was unaffected by water limitation along this gradient, while δ12C/ δ13C analyses showed that V. divaricata trees experienced drought within drier sites. V. divaricata also had higher herbivore loads in drier sites. A. mearnsii had higher herbivore loads on nutrient deficient trees and higher disease development in trees with sufficient nutrient levels. Comparisons of the nutrient economies of the two legume trees showed that they had similar leaf nutrient contents and resorption efficiencies, but they differed in the use of Biological Nitrogen Fixation (BNF). The native tree utilized BNF more than the invasive. We also tested the physiological effects of a native fungal species on the two tree species. We found the infection elicited more response from the invasive, while the native plant was almost non-responsive. Both plants had significantly longer lesions on infected seedlings than on control plants after inoculation with this pathogen. This difference in response offers a measure of support to the BRH, as the invasive may be more vulnerable to infection. The importance of using related, ecologically similar species in the assessment of the impacts of invasive alien plants is highlighted here. This may provide more information on the actual ecological interaction between native and invasive species within invaded ranges. Forest margins are very vulnerable and dynamic habitats. The influx of a new species into this habitat in the form of an invasive alien plant may therefore have much negative effects. We found support for the exchange of pest and pathogens where these two tree species co-occur. The two host species were very similar in their nutrient economies, creating a potential for competition for similar resources between A. mearnsii and V. divaricata. The environment had an influence on how these plants responded to pest and pathogens and this may be important under the predicted scenario of future climate change. / AFRIKAANSE OPSOMMING: Uitheemse indringer plant spesies het vernietigende effekte op die omgewings waarbinne hulle indring. Australiese Acacias, ‗n groep plante wat reg oor die wêreld aangeplant is vir ‗n reeks gebruike, maar wat uit plantasie areas ontsnap het en indringers geword het in baie lande, is besonder problematies. Acacia mearnsii is een van hierdie indringer uitheemse plant spesies, en in Suid Afrika is ook ‗n belangrike bosbou spesie. Dit is tans die vyfde mees wydverspreide uitheemse indringer plant in Suid Afrika, en word slegs beperk deur die baie droë Karoo, so dit is belangrik om die verskillende habitatte wat dit binnedring te ondersoek. Woudrandte, the grense van die Afromontane woudkompleks in Suid Afrika, is hoogs gefragmenteerd en is dus een van die mees bedreigde Biome in die land. Die wydverspreide woudrand boom Virgilia divaricata kom in hierdie woudrandte voor. Dit is ekologies eenders aan A. mearnsii, aangesien hierdie twee spesies baie kenmerke deel (wortelknop-vormende peulplante, woudpionier spesies, vining groeiend, aangepas tot brande). Hierdie spesies kom simpatries voor binne woudrandte wat deur A. mearnsii ingedring is, en in hierdie lokaliteite bestaan daar die potensiaal vir biologiese uitruiling van geassosieerde peste en patogene in die vorm van geleedpotiges en fungi spesies. Ons stel die hipotese dat hierdie twee spesies verkillende interaksies met hulle peste en patogene het, in ooreenstemming met die Vyand-Vrystellingshipotese (VVH) en die Biologiese-Weerstandshipotese (BWH), onderskeidelik. Ons het eers die geleedpotige assosieasie tussen hierdie twee boom spesies vergelyk en het bevind dat hulle baie geleedpotige spesies deel. Die inheemse boom het egter baie hoër getalle herbivore en algehele geleedpotige-assosiasies gehad as die indringer boom spesie, wat die voorspellings van die VVH ondersteun. Die verspreiding van hierdie twee spesies het ook ‗n effek gehad op hulle geleedpotige samestellings. Ons het ook hulle geassosieerde ophiostomatiede fungus assosiate en hulle herbivoor ladings bestudeer, en het bepaal hoe hierdie peste en patogene deur omgewingstoestande beinvloed is langs ‗n water gradient. Ons het ook die effek van hierdie peste en patogene op die voedingstof-inhoud van hierdie twee spesies vergelyk. A. meansii is nie geaffekteer deur waterbeperkings langs hierdie gradient nie, terwyl δ12C/ δ13C analises aangedui het dat V. divaricata bome droogte stres in droër lokaliteite ervaar het. V. divaricata het ook hoër herbivoorladings gehad in die droër lokaliteite. A. meanrsii het hoër herbivoorladings gehad op voedingstof-beperkte bome, en daar was verhoogde siekte-ontwikkeling in bome met genoegsame voiding. Vergelykings van die voedingstof-ekonomië van die twee peulplant bome het aangedui dat hulle eenderse blaarvoedingstof-inhoude en resorpsie effektiwiteite het, maar het verskil in die gebruik van Biologiese Stikstof Fiksasie (BSF). Die inheemse boom het meer van BSF gebruik gemaak as die indringer. Ons het ook die fisiologiese effekte van ‗n inheemse fungus spesie op die twee boomspesies getoets. Ons het bevind dat infeksie ‗n sterker reaksie in die indringer ontlok het, terwyl die inheemse plant feitlik glad nie op infeksie gereageer het nie. Beide plante het beduidend langer wondmerke in geinfekteerde saailinge ontwikkel as in kontrole plante na innokulasie met die patogeen. Hierdie verskil in reaksie verleen ‗n mate van ondersteuning aan die BWH, aangesien die indringer meer vatbaar mag wees teen infeksie. Die belang daarvan om verwante, ekologies soortgelyke spesies te gebruik in die bepaling van die effekte van uitheemse indringer spesies word hier beklemtoon. Dit mag meer inligting verskaf oor die werklike ekologiese interaksie tussen inheemse en indringer spesies binne verspreidings wat binnegedring is. Woudrandte is baie weerlose en dinamiese habitatte. Die invoer van nuwe spesies in hierdie habitat in die vorm van ‗n uitheemse indringer plant mag daarom baie negatiewe effekte hê. Ons het ondersteuning gevind vir die uitruiling van peste en patogene waar hierdie twee spesies saam voorkom. Hierdie spesies was baie eenders in terme van hulle voedingstof-ekonomië, wat die potensiaal skep vir kompetisie tussen A. mearnsii en V. divaricata. Die omgewing het ‗n effek gehad op hoe hierdie plante gereageer het op peste en patogene, en dit mag belangrik wees onder die huidig voorspelde senarios van toekomstige klimaatsverandering.