The politics of power in an economy in transition: Eskom and the electrification of South Africa 1980-1995

Thesis (Ph.D.)--University of the Witwatersrand, Commerce Faculty, 2000This study traces the history of the programmes to electrify white-owned commercial farms on South Africa's borders and black households, schools and clinics in the period 1980-1995 by Eskom, South Africa's public electric utility. In particular the study investigates why Eskom undertook these programmes and their macro- and micro-economic impact on the South African economy. The history of Eskom's attempt to assume responsibility for the management of Greater Soweto' s electricity supply in the late eighties is also documented. Greater Soweto is South Africa's largest and most important black township, and is situated to the south-west of Johannesburg. The reasons for this initiative and its connection to Eskom's black household electrification programmes is exposed. The methodological approach to the study involves analysing political, economic and institutional intelligence concerning Eskom's electrification programmes gathered from primary and secondary literature sources and interviews with senior Eskom staff, and others, in qualitative, and, where appropriate, quantitative terms. The results of this analysis suggest that politics played a crucial role in Eskom's decision to undertake these electrification programmes and that Eskom was an autonomous entity and lacked adequate regulatory oversight. With respect to the macro- and micro-economic benefits (GDP growth and job creation) arising from the progranune to electrify black households between 1990 and 1995 these are shown to be very much smaller than those claimed by Eskom. The reasons for this difference are explored and explained in detail. It was also found that large scale cross-subsidisation was required to sustain both the farm and black household electrification programmes. These findings required that matters of energy policy with respect to the sustainability of the programme to electrify black households be addressed. These policy issues are dealt with under three headings, financial issues, economic efficiency and equity. Finally suggestions are made for the way forward so that the electrification of black households in South Africa may be sustained.AC201

Expanding knowledge and practice of construction management systems and procedures.

This submission is a highly focused collection of research-based and scholarly publications in the specialist field of Construction Management. Emphasis is placed on management systems and procedures involved in the procurement and production phases of the total building process. A coherent, original, independent and significant contribution to the advancement and application of knowledge has been made through applied research and dissemination of findings to academic peers, construction industry professionals and students in higher education. This has been achieved through: academic, professional and research-based textbooks; research monographs; refereed papers in learned journals; refereed papers to premier national and international conferences; and papers to foremost construction industry professional institutions.Textbooks have been published by Macmillan, Thomas-Telford in collaboration with the Engineering and Physical Sciences Research Council (EPSRC), Longman and Palgrave with three commissioned by and contributing to the Chartered Institute of Building (CIOB) 'Education Framework' for construction industry. Peer-reviewed papers have been published by eminent journals based within the UK, North America, Australia, Hong Kong and China whilst refereed conference papers have been published both in the UK and internationally at leading research symposia. Among the refereed journal and conference papers presented, a number have merited prestigious awards reflecting "the outstanding contribution to research knowledge and communication within the construction industry" (ciob, 1988) and in recognition of "making a practical and lasting contribution towards the improvement of standards in building practice and education in building"(CIOB, 2004).This submission reflects a distinguished level of dissemination of applied research and scholarship over a twenty year period. The body of work presented has established a highly significant and authoritative contribution to the better understanding of construction management systems andprocedures. Furthermore, it has influenced, where applicable, thinking and practice within the subject field within research groups, higher education, the professions and the construction industry

Growth factor regulation of proliferation and survival of multipotential stromal cells

Multipotential stromal cells (MSCs) have been touted to provide an alternative to conservative procedures of therapy, be it heart transplants, bone reconstruction, kidney grafts, or skin, neuronal and cartilage repair. A wide gap exists, however, between the number of MSCs that can be obtained from the donor site and the number of MSCs needed for implantation to regenerate tissue. Standard methods of MSC expansion being followed in laboratories are not fully suitable due to time and age-related constraints for autologous therapies, and transplant issues leave questions for allogenic therapies. Beyond these issues of sufficient numbers, there also exists a problem of MSC survival at the graft. Experiments in small animals have shown that MSCs do not persist well in the graft environment. Either there is no incorporation into the host tissue, or, if there is incorporation, most of the cells are lost within a month. The use of growth and other trophic factors may be helpful in counteracting these twin issues of MSC expansion and death. Growth factors are known to influence cell proliferation, motility, survival and morphogenesis. In the case of MSCs, it would be beneficial that the growth factor does not induce differentiation at an early stage since the number of early-differentiating progenitors would be very low. The present review looks at the effect of and downstream signaling of various growth factors on proliferation and survival in MSCs

An investigation of novel genetic tools for the manipulation of CHO cell phenotypes during recombinant protein production

Chinese Hamster Ovary (CHO) cells are the most common mammalian cell line used around the world and are considered the “workhorse” for production of recombinant proteins in the pharmaceutical industry. Efforts have been made to optimise the production process through advancements in media formulation and improving process control strategies like bioreactor design, fed-batch feeding and temperature shift approaches, increasing batch titres from 50 mg/L to 5-10 g/L. However, it is believed that there is still room for improvement in the advent of media and process optimisation reaching a plateau. An alternative route to overcome this plateau is through engineering of the CHO host cells themselves. The overall aim of this PhD project was to identify and exploit endogenous CHO promoters to enhance heterologous protein expression. Having obtained ~ 30 CHO putative promoter sequences of varying length from 9 target genes from PCR, we screened and cloned 4 priority CHO promoter fragments into a variety of reporter vectors (GFP, Luciferase, p27 and EPO) to test their strength and utility. We have identified 3 novel temperature responsive promoters fragments from Cirbp SSu72 and Mdm2 genes and one constitutive promoter from a miRNA cluster [miR-17-92]. These promoters can permit moderate to high expression of a desired protein similarly to viral commercial ones such as cytomegalovirus (CMV) and simian virus (SV40) as well as boost expression levels of reporter proteins upon a temperature shift to 31oC. As a result, these novel tools are particularly advantageous in a bioprocess where reduced temperature is used already to increase protein production. In addition, we reported a ~94% decrease in clonal GFP stability of a CMV viral promoter versus our endogenous promoters over a 3 month timecourse experiment proving that viral promoters cannot sustain prolonged activity in culture like our novel endogenous promoter sequences. We have also shown that CHO clones overexpressing human XIAP exhibited 2/3-fold increased resistance to apoptosis and survival in extended culture settings compared to control cells. A secondary aim was to identify potential interacting miRNAs by utilising a novel pulldown method (miR-Capture), to isolate miRNAs targeting the anti-apoptotic XIAP mRNA in two different cell types, using a biotinylated anti-sense oligonucleotide capture affinity technique. Thus, identifying miRNAs which may impact on favourable phenotypes such as anti-apoptosis and increased growth rate may provide a means of improving CHO cell lines used for biopharmaceutical production. From the miR-Capture, there were 26 miRNAs detected in the human lysates and 14 in the CHO lysates. Four miRNAs (miR-124, miR-526b*, miR-760 and miR-877) were shown to be common from parallel CHO and human miR-Capture’s, using oligos designed against XIAP. Functional validation provided further evidence that miR-124 targets XIAP mRNA in CHO and human cells and may be a suitable target for miRNA engineering in CHO

Engineering liver

Interest in “engineering liver” arises from multiple communities: therapeutic replacement; mechanistic models of human processes; and drug safety and efficacy studies. An explosion of micro- and nanofabrication, biomaterials, microfluidic, and other technologies potentially affords unprecedented opportunity to create microphysiological models of the human liver, but engineering design principles for how to deploy these tools effectively toward specific applications, including how to define the essential constraints of any given application (available sources of cells, acceptable cost, and user-friendliness), are still emerging. Arguably less appreciated is the parallel growth in computational systems biology approaches toward these same problems—particularly in parsing complex disease processes from clinical material, building models of response networks, and in how to interpret the growing compendium of data on drug efficacy and toxicology in patient populations. Here, we provide insight into how the complementary paths of engineering liver—experimental and computational—are beginning to interplay toward greater illumination of human disease states and technologies for drug development.National Institutes of Health (U.S.) (UH2TR000496)National Institutes of Health (U.S.) (R01-EB 010246)National Institutes of Health (U.S.) (R01-ES015241)National Institutes of Health (U.S.) (P30-ES002109

Controlling multipotent stromal cell migration by integrating “course-graining” materials and “fine-tuning” small molecules via decision tree signal-response modeling

Biomimetic scaffolds have been proposed as a means to facilitate tissue regeneration by multi-potent stromal cells (MSCs). Effective scaffold colonization requires a control of multiple MSC responses including survival, proliferation, differentiation, and migration. As MSC migration is relatively unstudied in this context, we present here a multi-level approach to its understanding and control, integratively tuning cell speed and directional persistence to achieve maximal mean free path (MFP) of migration. This approach employs data-driven computational modeling to ascertain small molecule drug treatments that can enhance MFP on a given materials substratum. Using poly(methyl methacrylate)-graft-poly(ethylene oxide) polymer surfaces tethered with epidermal growth factor (tEGF) and systematically adsorbed with fibronectin, vitronectin, or collagen-I to present hTERT-immortalized human MSCs with growth factor and extracellular matrix cues, we measured cell motility properties along with signaling activities of EGFR, ERK, Akt, and FAK on 19 different substrate conditions. Speed was consistent on collagen/tEGF substrates, but low associated directional persistence limited MFP. Decision tree modeling successfully predicted that ERK inhibition should enhance MFP on collagen/tEGF substrates by increasing persistence. Thus, we demonstrated a two-tiered approach to control MSC migration: materials-based “coarse-graining” complemented by small molecule “fine-tuning”.National Institutes of Health (U.S.) (NIH grant R01-DE019523)National Institutes of Health (U.S.) (NIH Cell Migration Consortium U54-GM064346)National Institutes of Health (U.S.) (NIH grant R01-GM018336)National Institutes of Health (U.S.) (NIH grant R01-DE019523

The Dormancy Dilemma: Quiescence versus Balanced Proliferation

Metastatic dissemination with subsequent clinical outgrowth leads to the greatest part of morbidity and mortality from most solid tumors. Even more daunting is that many of these metastatic deposits silently lie undetected, recurring years to decades after primary tumor extirpation by surgery or radiation (termed metastatic dormancy). As primary tumors are frequently curable, a critical focus now turns to preventing the lethal emergence from metastatic dormancy. Current carcinoma treatments include adjuvant therapy intended to kill the cryptic metastatic tumor cells. Because such standard therapies mainly kill cycling cells, this approach carries an implicit assumption that metastatic cells are in the mitogenic cycle. Thus, the pivotal question arises as to whether clinically occult micrometastases survive in a state of balanced proliferation and death, or whether these cells undergo at least long periods of quiescence marked by cell-cycle arrest. The treatment implications are thus obvious—if the carcinoma cells are cycling then therapies should target cycling cells, whereas if cells are quiescent then therapies should either maintain dormancy or be toxic to dormant cells. Because this distinction is paramount to rational therapeutic development and administration, we investigated whether quiescence or balanced proliferation is the most likely etiology underlying metastatic dormancy. We recently published a computer simulation study that determined that balanced proliferation is not the likely driving force and that quiescence most likely participates in metastatic dormancy. As such, a greater emphasis on developing diagnostics and therapeutics for quiescent carcinomas is needed.National Institutes of Health (U.S.). National Center for Advancing Translational Sciences (Grant UH2TR000496

Production of Reactive Oxygen Species by Multipotent Stromal Cells/Mesenchymal Stem Cells Upon Exposure to Fas Ligand

Multipotent stromal cells (MSCs) can be differentiated into osteoblasts and chondrocytes, making these cells candidates to regenerate cranio-facial injuries and lesions in long bones. A major problem with cell replacement therapy, however, is the loss of transplanted MSCs at the site of graft. Reactive oxygen species (ROS) and nonspecific inflammation generated at the ischemic site have been hypothesized to lead to MSCs loss; studies in vitro show MSCs dying both in the presence of ROS or cytokines like FasL. We questioned whether MSCs themselves may be the source of these death inducers, specifically whether MSCs produce ROS under cytokine challenge. On treating MSCs with FasL, we observed increased ROS production within 2 h, leading to apoptotic death after 6 h of exposure to the cytokine. N-acetyl cysteine, an antioxidant, is able to protect MSCs from FasL-induced ROS production and subsequent ROS-dependent apoptosis, though the MSCs eventually succumb to ROS-independent death signaling. Epidermal growth factor (EGF), a cell survival factor, is able to protect cells from FasL-induced ROS production initially; however, the protective effect wanes with continued FasL exposure. In parallel, FasL induces upregulation of the uncoupling protein UCP2, the main uncoupling protein in MSCs, which is not abrogated by EGF; however, the production of ROS is followed by a delayed apoptotic cell death despite moderation by UCP2. FasL-induced ROS activates the stress-induced MAPK pathways JNK and p38MAPK as well as ERK, along with the activation of Bad, a proapoptotic protein, and suppression of survivin, an antiapoptotic protein; the latter two key modulators of the mitochondrial death pathway. FasL by itself also activates its canonical extrinsic death pathway noted by a time-dependent degradation of c-FLIP and activation of caspase 8. These data suggest that MSCs participate in their own demise due to nonspecific inflammation, holding implications for replacement therapies.National Institute of General Medical Sciences (U.S.) (GM069668)National Institute of Dental and Craniofacial Research (U.S.) (DE019523

Measurement of Linear Stark Interference in 199Hg

We present measurements of Stark interference in the 6$^1S_0$ $\rightarrow$ 6$^3P_1$ transition in $^{199}$Hg, a process whereby a static electric field $E$ mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to $E$-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, $a_{SI}$ = $(a_{M1} + a_{E2})$ = (5.8 $\pm$ 1.5)$\times 10^{-9}$ (kV/cm)$^{-1}$, agrees with relativistic, many-body predictions and confirms that earlier central-field estimates are a factor of 10 too large. More importantly, this study validates the capability of the $^{199}$Hg EDM search apparatus to resolve non-trivial, controlled, and sub-nHz Larmor frequency shifts with EDM-like characteristics.Comment: 4 pages, 4 figures, 1 table; revised in response to reviewer comment

Surface Tethered Epidermal Growth Factor Protects Proliferating and Differentiating Multipotential Stromal Cells from FasL-Induced Apoptosis

Multipotential stromal cells or mesenchymal stem cells (MSCs) have been proposed as aids in regenerating bone and adipose tissues, as these cells form osteoblasts and adipocytes. A major obstacle to this use of MSC is the initial loss of cells postimplantation. This cell death in part is due to ubiquitous nonspecific inflammatory cytokines such as FasL generated in the implant site. Our group previously found that soluble epidermal growth factor (sEGF) promotes MSC expansion. Furthermore, tethering EGF (tEGF) onto a two-dimensional surface altered MSC responses, by restricting epidermal growth factor receptor (EGFR) to the cell surface, causing sustained activation of EGFR, and promoting survival from FasL-induced death. sEGF by causing internalization of EGFR does not support MSC survival. However, for tEGF to be useful in bone regeneration, it needs to allow for MSC differentiation into osteoblasts while also protecting emerging osteoblasts from apoptosis. tEGF did not block induced differentiation of MSCs into osteoblasts, or adipocytes, a common default MSC-differentiation pathway. MSC-derived preosteoblasts showed increased Fas levels and became more susceptible to FasL-induced death, which tEGF prevented. Differentiating adipocytes underwent a reduction in Fas expression and became resistant to FasL-induced death, with tEGF having no further survival effect. tEGF protected undifferentiated MSC from combined insults of FasL, serum deprivation, and physiologic hypoxia. Additionally, tEGF was dominant in the face of sEGF to protect MSC from FasL-induced death. Our results suggest that MSCs and differentiating osteoblasts need protective signals to survive in the inflammatory wound milieu and that tEGF can serve this function.National Institute of General Medical Sciences (U.S.) (GM069668)National Institute of Dental and Craniofacial Research (U.S.) (DE019523