83 research outputs found
A PRACTICAL APPROACH TO MANAGING UNCERTAINTY IN THE MEASUREMENT AND VERIFICATION OF ENERGY EFFICIENCY SAVINGS
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
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
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
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
Recommended from our members
Brain multiplexes reveal morphological connectional biomarkers fingerprinting late brain dementia states
Accurate diagnosis of mild cognitive impairment (MCI) before conversion to Alzheimer’s disease (AD) is invaluable for patient treatment. Many works showed that MCI and AD affect functional and structural connections between brain regions as well as the shape of cortical regions. However, ‘shape connections’ between brain regions are rarely investigated -e.g., how morphological attributes such as cortical thickness and sulcal depth of a specific brain region change in relation to morphological attributes in other regions. To fill this gap, we unprecedentedly design morphological brain multiplexes for late MCI/AD classification. Specifically, we use structural T1-w MRI to define morphological brain networks, each quantifying similarity in morphology between different cortical regions for a specific cortical attribute. Then, we define a brain multiplex where each intra-layer represents the morphological connectivity network of a specific cortical attribute, and each inter-layer encodes the similarity between two consecutive intra-layers. A significant performance gain is achieved when using the multiplex architecture in comparison to other conventional network analysis architectures. We also leverage this architecture to discover morphological connectional biomarkers fingerprinting the difference between late MCI and AD stages, which included the right entorhinal cortex and right caudal middle frontal gyrus
Recommended from our members
Multimodal and Multiscale Deep Neural Networks for the Early Diagnosis of Alzheimer’s Disease using structural MR and FDG-PET images
Alzheimer’s Disease (AD) is a progressive neurodegenerative disease where biomarkers for disease based on pathophysiology may be able to provide objective measures for disease diagnosis and staging. Neuroimaging scans acquired from MRI and metabolism images obtained by FDG-PET provide in-vivo measurements of structure and function (glucose metabolism) in a living brain. It is hypothesized that combining multiple different image modalities providing complementary information could help improve early diagnosis of AD. In this paper, we propose a novel deep-learning-based framework to discriminate individuals with AD utilizing a multimodal and multiscale deep neural network. Our method delivers 82.4% accuracy in identifying the individuals with mild cognitive impairment (MCI) who will convert to AD at 3 years prior to conversion (86.4% combined accuracy for conversion within 1–3 years), a 94.23% sensitivity in classifying individuals with clinical diagnosis of probable AD, and a 86.3% specificity in classifying non-demented controls improving upon results in published literature
Recommended from our members
The impact of PICALM genetic variations on reserve capacity of posterior cingulate in AD continuum
Phosphatidylinositolbinding clathrin assembly protein (PICALM) gene is one novel genetic player associated with late-onset Alzheimer’s disease (LOAD), based on recent genome wide association studies (GWAS). However, how it affects AD occurrence is still unknown. Brain reserve hypothesis highlights the tolerant capacities of brain as a passive means to fight against neurodegenerations. Here, we took the baseline volume and/or thickness of LOAD-associated brain regions as proxies of brain reserve capacities and investigated whether PICALM genetic variations can influence the baseline reserve capacities and the longitudinal atrophy rate of these specific regions using data from Alzheimer’s Disease Neuroimaging Initiative (ADNI) dataset. In mixed population, we found that brain region significantly affected by PICALM genetic variations was majorly restricted to posterior cingulate. In sub-population analysis, we found that one PICALM variation (C allele of rs642949) was associated with larger baseline thickness of posterior cingulate in health. We found seven variations in health and two variations (rs543293 and rs592297) in individuals with mild cognitive impairment were associated with slower atrophy rate of posterior cingulate. Our study provided preliminary evidences supporting that PICALM variations render protections by facilitating reserve capacities of posterior cingulate in non-demented elderly
The optimization of structural dynamic data acquisition.
Thesis (M.Ing.) -- University of Stellenbosch, 1983.Full text to be digitised and attached to bibliographic record
Elmo in the Hinterland
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
- …