83 research outputs found

    A PRACTICAL APPROACH TO MANAGING UNCERTAINTY IN THE MEASUREMENT AND VERIFICATION OF ENERGY EFFICIENCY SAVINGS

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    Measurement and verification (M&V) is fundamental in determining the impact of energy efficiency (EE) interventions. However, accurately quantifying the EE savings on complex industrial systems can present several technical challenges. It is of critical importance that these challenges be practically addressed within regulatory requirements when applying for tax-based EE incentives. In this study, the key uncertainties affecting the M&V of Section 12L EE tax incentive applications are identified. A novel approach provides practical guidelines to manage and mitigate uncertainty. This approach ensures that reported savings are a fair and compliant reflection of the actual savings achieved. The presented case studies show that uncertainty can affect up to 30 per cent of reported savings. This emphasises the significant impact of uncertainty, and quantifies the benefit of compliant uncertainty management. Ultimately, this study provides valuable insight into the practical implementation of tax-based directives intended to stimulate sustainable development

    Influence of partial and complete glutamine-and glucose deprivation of breast-and cervical tumorigenic cell lines

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    BACKGROUND : Due to their high proliferative requirements, tumorigenic cells possess altered metabolic systems whereby cells utilize higher quantities of glutamine and glucose. These altered metabolic requirements make it of interest to investigate the effects of physiological non-tumorigenic concentrations of glucose and glutamine on tumorigenic cells since deprivation of either results in a canonical amino acid response in mammalian cell. METHODS : The influence of short-term exposure of tumorigenic cells to correlating decreasing glutamine- and glucose quantities were demonstrated in a highly glycolytic metastatic breast cell line and a cervical carcinoma cell line. Thereafter, cells were propagated in medium containing typical physiological concentrations of 1 mM glutamine and 6 mM glucose for 7 days. The effects on morphology were investigated by means of polarizationoptical transmitted light differential interference contrast. Flow cytometry was used to demonstrate the effects of glutamine-and glucose starvation on cell cycle progression and apoptosis induction. Fluorometrics were also conducted to investigate the effects on intrinsic apoptosis induction (mitocapture), reactive oxygen species production (2,7-dichlorofluorescein diacetate) and acidic vesicle formation (acridine orange). RESULTS : Morphological data suggests that glutamine-and glucose deprivation resulted in reduced cell density and rounded cells. Glutamine-and glucose starvation also resulted in an increase in the G2M phase and a sub-G1 peak. Complete starvation of glutamine and glucose resulted in the reduction of the mitochondrial membrane potential in both cell lines with MDA-MB-231 cells more prominently affected when compared to HeLa cells. Further, starved cells could not be rescued sufficiently by propagating since cells possessed an increase in reactive oxygen species, acidic compartments and vacuole formation. CONCLUSION : Starvation from glutamine and glucose for short periods resulted in decreased cell density, rounded cells and apoptosis induction by means of reactive oxygen species generation and mitochondrial dysfunction. In addition, the metastatic cell line reacted more prominently to glutamine-and glucose starvation due to their highly glycolytic nature. Satisfactory cellular rescue was not possible as cells demonstrated oxidative stress and depolarized mitochondrial membrane potential. This study contributes to the knowledge regarding the in vitro effects and signal transduction of glucose and/or L-glutamine deprivation in tumorigenic cell lines.Grants from the Cancer Association of South Africa, the Struwig Germeshuysen Trust, RESCOM (Research Council of the University of Pretoria), the South African National Research Foundation and Medical Research Council.http://www.cellandbioscience.comam201

    The genetic architecture of the human cerebral cortex

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    The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

    Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors

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    Background Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. Results Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. Conclusions Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.Peer reviewe

    The optimization of structural dynamic data acquisition.

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    Thesis (M.Ing.) -- University of Stellenbosch, 1983.Full text to be digitised and attached to bibliographic record

    Elmo in the Hinterland

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    A lack in infrastructure and skills, in an inherited Apartheid spatial legacy, leaves a critical opening for much needed added spatial value. By investigating and supporting existing networks and contributing to existing typologies, this dissertation speculates on educational resource infrastructure provision to marginalized communities in Pretoria, South Africa. It is a rethinking of our South African city landscapes and civic/pedagogical architectural offerings, manifesting a critical stance to foster a prosperous community that has the potential to thrive. Focusing a speculative knowledge exchange infrastructure intervention on already existing networks; this dissertation aims to resolve the potential of current typologies in urban planning, and the ability to foster a new teacher, pupil and community education infrastructure to empower local stakeholders to improve provided services. Building a prosperous future on top of past spatial inheritance.Mini Dissertation MArch(Prof)--University of Pretoria, 2018.ArchitectureMArch(Prof)Unrestricte
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