Although it has long been recognized that physiological acclimation of photosynthesis and respiration can occur in plants exposed to changing environmental conditions (e.g. light, temperature or stress), the extent of acclimation in different tissues (i.e. pre-existing and new foliage) however, has not received much attention until recently. Furthermore, few studies have investigated the extent of photosynthetic and respiratory acclimation under natural conditions, where air temperatures vary diurnally and seasonally. In this study, the effects of variations in temperature on respiratory CO2 loss and photosynthetic carbon assimilation were examined under both controlled and natural environments. The purpose of the investigations described in this thesis was to identify the effects acclimation would have on two key metabolic processes in plants exposed to temperature change, with emphasis also placed on the role of nutrition (nitrogen) and respiratory enzymatic characteristics on the potential for acclimation in two contrasting tree species, Pinus radiata and Populus deltoides. Controlled-environment studies (Chapter 2 and 3) established that rates of foliar respiration are sensitive to short-term changes in temperature (increasing exponentially with temperature) but in the longer-term (days to weeks), foliar respiration acclimates to temperature change. As a result, rates of dark respiration measured at any given temperature are higher in cold-acclimated and lower in warm-acclimated plants than would be predicted from an instantaneous response. Acclimation in new foliage (formed under the new temperature environment) was found to result in respiratory homeostasis (i.e. constant rates of foliar respiration following long-term changes in temperature, when respiration is measured at the prevailing growth temperature). Available evidence suggests that substantial adjustments in foliar respiration tend to be developmentally dependent. This may in part explain why respiratory homeostasis was only observed in new but not in pre-existing tissues. Step changes in temperature (cold and warm transfers) resulted in significant changes in photosynthetic capacity. However, in stark contrast to the findings of respiration, there was little evidence for photosynthetic acclimation to temperature change. The results obtained from field studies (Chapter 4) show that in the long-term over a full year, dark respiration rates in both tree species were insensitive to temperature but photosynthesis retained its sensitivity, increasing with increasing temperature. Respiration in both species showed a significant downregulation during spring and summer and increases in respiratory capacity were observed in autumn and winter. Thermal acclimation of respiration was associated with a change in the concentration of soluble sugars. Hence, acclimation of dark respiration under a naturally changing environment is characterized by changes in the temperature sensitivity and apparent capacity of the respiratory apparatus. The results from controlled and natural-environment studies were used to drive a leaflevel model (which accounted for dark respiratory acclimation) with the aim of forecasting the overall impact of responses of photosynthesis and respiration in the long term (Chapter 5). Modellers utilise the temperature responses of photosynthesis and respiration to parameterize carbon exchange models but often ignore acclimation and use only instantaneous responses to drive such models. The studies here have shown that this can result in erroneous estimates of carbon exchange as strong respiratory acclimation occurs over longer periods of temperature change. For example, it was found here that the failure to factor for dark respiratory acclimation resulted in the underestimation of carbon losses by foliar respiration during cooler months and an overestimation during warmer months - such discrepancies are likely to have an important impact on determinations of the carbon economy of forests and ecosystems. The overall results substantiate the conclusion that understanding the effect of variations in temperature on rates of carbon loss by plant respiration is a prerequisite for predicting estimates of atmospheric CO2 release in a changing global environment. It has been shown here that within a moderate range of temperatures, rate of carbon uptake by photosynthesis exceeds the rate of carbon loss by plant respiration in response to warming as a result of strong respiratory acclimation to temperature change. This has strong implications for models which fail to account for acclimation of respiration. At present, respiration is assumed to increase with increasing temperatures. This erroneous assumption supports conclusions linking warming to the reinforcement of the greenhouse effect.

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Introduction: Liposuction has undergone several improvements since its first description, including changes in the cannulas, variation in the concentration of the infiltrating solution, and the use of different devices and technologies. The use of laser technology devices for lipolysis and stimulation of skin retraction has contributed to the procedure. This article presents the authors’ experience with laser lipolysis in 400 patients, within a 5-year period, and discusses the principles of the technology and its effect on tissues. Methods: This is a study performed between July 2007 and July 2012 and included 400 patients who underwent laser lipolysis. All procedures were performed following the original protocol – infiltration of cold saline, passage of the cannula with an optic fiber for conducting the energy needed for laser lipolysis, skin retraction, and finally, conventional liposuction. Results: Hospitalization type ranged from outpatient to overnight surgery. Approximately 45% (180 of 400) of patients had minimal bruising, with involvement of 2% or more of the affected body surface. Hematoma, seroma, and dehiscence occurred in a total of 9% (36 of 400) of patients. We did not find any case of thermal burn of the skin. Conclusions: Laser lipolysis performed according to the described technique was safe and reproducible.

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A thesis submitted to the Faculty of Humanities, University of the Witwatersrand, Johannesburg in fulfillment of the requirements for the degree of Doctor of Philosophy December 2015 / Introduction South Africa is characterised by numerous dichotomies and diversities, within which its two-tier healthcare system operates. An under-resourced state sector serves a majority of the population and a resource-intensive private sector serves a small minority. Within the constitutional framework of human rights and distributive justice there are nevertheless expectations of fair and equal access to healthcare services. There is furthermore an expectation of quality care across the health system, in spite of a number of systemic challenges related to staff and equipment shortages, unrealistic working hours and poor working conditions. Organ transplant is available to different degrees within the South African healthcare sector. Whilst transplant programmes are burgeoning internationally, cadaver transplant numbers in South Africa have decreased over recent years as donor organs have become increasingly scarce. Current research suggests that these challenges to transplant in South Africa arise from aspects of personal and cultural beliefs, illegal transplant practices and resource constraints - which all serve to compromise the ethical implementation of transplant services in the two-tier healthcare system. The impact of interprofessional communication and transplant professional–patient communication has not been previously researched in South Africa. However, research into other healthcare issues has shown that communication is vital to the ethical provision of healthcare services, especially those which involve patient-centeredness and multidisciplinary interaction. Transplant involves a significant amount of communication within a particularly large network of recipients and their families, cadaver donor families, living donors and a range of transplant professionals. This communication seems a vital part of the transplant process, disseminating information which role-players need in order to promote favourable outcomes. Given the extensive networks involved in the transplant process, communication would seem to be a fertile area for research. This study aimed to explore communication in organ transplant in Gauteng province, South Africa. It considered both interprofessional communication and communication with patients as this took place within the hierarchical healthcare system and throughout the transplant process. An ethics of care framework was utilised in order to account for the expectations of care which South Africans confer upon their health system. Methods The study took place in the Gauteng province of South Africa across six healthcare institutions. Both the state and the private sector were equally represented. Altogether, thirty in-depth interviews with transplant professionals, two focus groups with transplant coordinators, two interviews with cadaver donor families, and one focus group with living kidney donors, were conducted. Thematic analysis and triangulation of the data utilising Braun and Clarke’s (2006) principles revealed three main themes relating to context, communication with patients, and interprofessional communication Findings The South African transplant context is complex and multifaceted, shaped by both the patients’ expectations of care and the transplant professionals’ perceptions of care. These expectations and perceptions are influenced by personal beliefs, suspicions of biomedicine, the media, and resource inequalities which pose challenges to accessing transplant services. The transplant context is characterised by ethical dilemmas relating to distributive justice, as questions about resource distribution and allocation of donor organs are raised. Transplant communication is influenced by context and varies depending upon role-players in transplant and the different phases of transplant. Demands for care by those hoping to receive an organ had a noticeable influence on transplant professional-potential recipient communication in the pre-transplant phase, a period when emotions of desperation and uncertainty were prominent. By the time recipients had received their organ and entered the more stable post-transplant phase, a relationship of trust developed in which communication was regular and caring roles seemed fulfilled. The opposite trend was evident in communication between transplant professionals and donor families. This was characterised by notions of care in the pre-transplant phase, contrasting with a perception amongst donor families that care was sometimes overlooked in the post-transplant phase - a time often imbued with chronic uncertainty. Even in the pre-transplant phase numerous ethical issues surrounding autonomy, decision-making and informed consent proved to complicate and challenge transplant communication. Interprofessional communication was shaped by hierarchical institutional organisation, a lack of continuity of care, and resource constraints, all of which challenged transplant professionals seeking to provide care, and sometimes resulted in aggressive interchanges. The pressure to procure an organ timeously – which could result in patient care and professional respect being somewhat disregarded – could so compromise interprofessional communications that moral distress was created. Furthermore, as a result of miscommunications, an ethical vacuum where the best interests of patients in the transplant process were not, apparently, a foremost consideration, was identified. Conclusion Transplant is a highly complex process requiring a number of different communication styles and skills and accompanied by intricate ethical challenges. Although transplant professionals seemed cognisant of the need for careful communication, inequalities, resource scarcity and conflict intervened to create a space for moral distress and uncertainty in which communication was affected, and the provision of care was the casualty. Appraising results within an ethics of care framework suggests that transplant in Gauteng cannot be considered to be a process fully informed by the imperative of care. The ethics of care proved to be a helpful framework for understanding transplant communication in Gauteng because of the way it accounts for interpersonal relationships - fundamental to the transplant process - whilst also emphasising the importance of resources necessary to provide good care. It was concluded that in the current environment, where there is little legal direction or political buy-in, transplant in Gauteng will be unable to reach its full potential. / MT2016

Dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa / In the forestry industry the requirement for the maintenance of a broad genetic base is integral to the success of breeding programmes such as those for Eucalyptus grandis, an important species to the South African forestry industry. Plant cryopreservation is an economical option to maintain such a genetic base, as it allows storage of vegetative materials at sub-zero temperatures, while maintaining juvenility. However, successful cryopreservation of this sub-tropical species has been restricted by its sensitivity to cryopreparative drying. As a consequence, the viability of material is reduced even before reaching the freezing stage. Despite this abiotic stress restriction, evidence of upstream ‘cross-talk’ implying downstream ‘cross-tolerance’ has suggested the possibility that cold acclimation may improve the tolerance responses towards dehydration stress by means of ‘cross-acclimation’. It was therefore the aim of the study to understand some of the physiological and biochemical responses of in vitro E. grandis shoots to different non-freezing low (chilling) temperatures and exposure periods, and to establish an appropriate ‘cross-acclimation’ regime for the physical drying pre-treatment. E. grandis shoot clusters (4-8 leaves and 2-5 axillary buds) were exposed to the chilling temperatures of 5°C, 10°C or 15°C for 1 or 3 days. The physiological and biochemical responses were evaluated, and thereafter the appropriate cold acclimation (or ‘cross-acclimation’) regime selected. The appropriate physical drying time was also selected for shoot clusters according to their physiological responses. When the appropriate regimes had been determined, the physiological and biochemical responses of shoot clusters treated consecutively to cold acclimation and then physical drying were evaluated. The physiological responses evaluated were water content, viability, and vigour (i.e. the number of visible axillary buds and shoots produced over 2 weeks). The biochemical responses measured were the concentrations of: 1) total soluble sugars, 2) starch, 3) phenolic acid, and 4) superoxide. The data suggested that the appropriate cold acclimation regime was treatment at 10°C for 3 days. This was based on the accumulation of the high levels of phenolic acid (3.05 ± 0.09 mg GAE.g-1 FWS) and positive vigour responses (11.90 ± 0.60 visible axillary buds/week and 3.10 ± 0.20 visible shoots/week), compared with the other chilling temperature treatments. The appropriate drying time selected for shoot clusters was 80 min over activated silica gel to achieve a water content of 0.32 ± 0.04 g water.g-1 FWS. In the dried material there were high levels of soluble sugars (47.65 ± 1.90% of the fresh weight of shoots) and unknown components that accounted for 48.10 ± 1.86% of the fresh weight, followed by phenolic acid (3.09 ± 0.05%) and proline (0.490 ± 0.011%). Despite these measured responses, viability of the shoots was impacted by drying, dropping to 88.9 ± 3.9%. When shoot clusters were pre-treated at 10°C for 3 days and then physically dried, viability of all (100%) the material was retained and the water content did not drop as low as with physical drying alone, dropping to 0.52 ± 0.05 g water.g-1 FWS. The biochemical responses showed that tolerance was strongly dependent on a high proportion of soluble sugars (83.66 ± 1.48% of the fresh weight of shoots) and phenolic acid (3.77 ± 0.12%), followed by proline (0.406 ± 0.018%). The study had confirmed that ‘cross-acclimation’ through means of cold acclimation (chilling pre-treatment at 10°C for 3 days) can induce ‘cross-tolerance’ towards physical drying, where osmotic adjustments and osmoprotection appeared to have been improved. It is therefore possible that this may have the potential to improve survival during the latter stages of the cryopreservation procedure, despite the higher retention of water in shoot clusters after drying.

Mechanisms for human memory T cell differentiation and maintenance have predominantly been inferred from studies of peripheral blood, though the majority of T cells reside in lymphoid and non-lymphoid sites. Studies in mice have shown that memory T cells in non-lymphoid sites provide superior protection to pathogens compared to those in blood, defining a subset known as tissue-resident memory T cells (TRM), with emerging roles in lymphoid sites. There are many key unknown aspects of TRM biology in human tissues including if TRM have superior functional abilities, the mechanisms for maintenance of TRM in lymphoid and non-lymphoid sites, and the relatedness of tissue and blood localized T cell subsets. Through a collaboration with the local organ procurement agency, we obtained samples from >15 tissue sites from healthy organ donors of all ages. We analyzed CD8+ T cells in diverse sites and found the majority of TRM cells in lymph nodes (LNs) display an increased proliferative capacity, increased expression of TCF-1, and decreased turnover compared to TRM and effector memory (TEM) cells in other sites including blood, bone marrow (BM), spleen and lung. Further, we identified that exposure to type 1 interferons results in increased downregulation of TCF-1 expression during cell divisions driven by T cell receptor (TCR) stimulation. We investigated the relatedness of CD4+ and CD8+ T cell subsets, including central memory (TCM), effector memory (TEM), TRM, and terminal effectors (TEMRA) by sequencing TCR rearrangements. From diversity analysis of TCR repertoires we found that effector and memory subsets are maintained in a hierarchy from most to least diverse (TCM > TEM and TRM > TEMRA) that is largely conserved across tissues and CD4+ and CD8+ T cell lineages. Overlap analysis revealed the low and high relatedness of TCM and TEMRA cells respectively and this was highly conserved across tissues; in contrast, we found the relatedness of TEM and TRM was more dynamic across tissues. Together, these findings have implications for immune monitoring and modulation, highlighting that lymph nodes may function as reservoirs for long-lived memory T cells with high functional capacity; additionally, we identify cell extrinsic signals that regulate tissue-specific maintenance of T cell memory in lymph node sites.

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Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisor: Christopher M. Modlesky, Dept. of Health, Nutrition, and Exercise Sciences. Includes bibliographical references.