Collection D

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https://scholar.sun.ac.za/handle/10019.1/8528

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1-[(1-Methyl-1H-imidazol-5-yl)methyl]-1H-indole-5-carbonitrile
(International Union of Crystallography, 2012) De Jager, Josephus Jacobus ; Smith, Vincent J.
In the title compound, C14H12N4, the dihedral angle between the indole ring system (r.m.s. deviation = 0.010 Å) and the imidazole ring is 77.70 (6)°. In the crystal, molecules are linked by C—H⋯N hydrogen bonds. One set of hydrogen bonds forms an undulating chain running parallel to the b-axis direction, while the other undulating chain is parallel to the c-axis direction. In combination, (100) sheets result.
18-Membered heterometallacyclic gold(I) compounds : structural influences of co-crystallized solvent
(De Gruyter, 2012) Dobrzanska, Liliana; Strasser, Crishtoph E.; Schmidbaur, Hubert; Raubenheimer, Helgard G.
5-Chloro-1-(4-methylphenylsulfonyl)-1H-indole
(International Union of Crystallography, 2012) Hassam, Mohammad; Smith, Vincent J.
The architecture of antagonistic networks : node degree distribution, compartmentalization and nestedness
(International Academy of Ecology and Environmental Sciences, 2015-12-01) Nuwagaba, Savannah; Hui, Cang
Describing complex ecosystems as networks of interacting components has proved fruitful – revealing many distinctive patterns and dynamics of ecological systems. Of these patterns, three have often been brought up in literature, including species degree distribution, compartmentalization and nestedness, due largely to their implications for the functionality and stability of communities. Here, using 61 empirical antagonistic networks, we aim to settle the inconsistency in literature by (i) fitting their node degree distributions to five different parametric models and identifying the one fits the best, (ii) measuring the levels of nestedness and compartmentalization of these 61 networks and testing their significance using different null models, and (iii) exploring how network connectance affects these three network architecture metrics. This research showed that most antagonistic networks do not display power law degree distributions and that resource species are generally uniformly distributed. We also clearly showed that the conclusion of whether a network is significantly compartmentalized or nested depends largely on the null model used.
Bioactive Compounds Inspired by Nature: Synthesis, Stability & Delivery
(2020-01-13) van der Westhuyzen, Alet E; Van Otterlo, Willem A. L.; Klumperman, Bert
Bovine tuberculosis in African buffalo (Syncerus caffer): Progression of pathology during infection
(PLOS, 2022-11-11) Lakin, Hilary Ann; Tavalire, Hannah; Sakamoto, Kaori; Buss, Peter; Miller, Michele; Budischak, Sarah A.; Raum, Kristina; Ezenwa, Vanessa O.; Beechler, Brianna; Jolles, Anna
Background Bovine tuberculosis (BTB) is a zoonotic disease of global importance endemic in African buffalo (Syncerus caffer) in sub-Saharan Africa. Zoonotic tuberculosis is a disease of global importance, accounting for over 12,000 deaths annually. Cattle affected with BTB have been proposed as a model for the study of human tuberculosis, more closely resembling the localization and progression of lesions in controlled studies than murine models. If disease in African buffalo progresses similarly to experimentally infected cattle, they may serve as a model, both for human tuberculosis and cattle BTB, in a natural environment. Methodology/Principal findings We utilized a herd of African buffalo that were captured, fitted with radio collars, and tested for BTB twice annually during a 4-year-cohort study. At the end of the project, BTB positive buffalo were culled, and necropsies performed. Here we describe the pathologic progression of BTB over time in African buffalo, utilizing gross and histological methods. We found that BTB in buffalo follows a pattern of infection like that seen in experimental studies of cattle. BTB localizes to the lymph nodes of the respiratory tract first, beginning with the retropharyngeal and tracheobronchial lymph nodes, gradually increasing in lymph nodes affected over time. At 36 months, rate of spread to additional lymph nodes sharply increases. The lung lesions follow a similar pattern, progressing slowly, then accelerating their progression at 36 months post infection. Lastly, a genetic marker that correlated to risk of M. bovis infection in previous studies was marginally associated with BTB progression. Buffalo with at least one risk allele at this locus tended to progress faster, with more lung necrosis. Conclusions/Significance The progression of disease in the African buffalo mirrors the progression found in experimental cattle models, offering insight into BTB and the interaction with its host in the context of naturally varying environments, host, and pathogen populations.
Computational Assessment and Visualization of Guest Inclusion in Porous Crystalline Materials
(2020-11) van Heerden, Dewald Pepler; Barbour, Leonard J.
Deep Learning-Enabled Temperature Simulation of a Greenhouse Tunnel
(IWACP, 2023) Jogunola, O.; Hull. K.J.; Mabitsela, M. M.; Phiri, E.E; Adebisi, B.; Booysen, MJ
Agriculture is poised to suffer greatly from the effects of climate change. Prediction models, using deep learning, have been developed that can simulate and predict conditions in open field farming to combat the climate variability from climate change. However, deep learning used in precision agriculture, specifically greenhouse tunnels, is under-researched despite also being affected by this variability. Utilising tunnel data collected over 42 days, two hybrid deep learning models were designed. Specifically, a hybrid of convolutional neural network (CNN) and Long Short-Term Memory (LSTM), and a hybrid of CNN and Bidirectional LSTM (BLSTM). The models are designed to forecast the internal temperature of the tunnel to support its management. The cooling wet wall state, solar irradiance, inside and outside temperature of the tunnel are input variables to the developed deep-learning models. Two scenarios are discussed with the results, the first scenario includes all the external variables as input, while the second scenario only considers the internal temperature as input. Results show a performance improvement of 48% and 14% computation time for the CNN-LSTM compared to the CNN-BLSTM model for the two scenarios, respectively. In terms of the measured loss metrics, both models had varied performance and model fitness, with an average mean square error of 0.025 across the models and scenarios.
Disorganized borders : a review of the literature on disorganized attachment in the etiology of Borderline Personality disorder
(Stellenbosch : Stellenbosch University, 2006) Vorster, Jeanne; Kruger, Lou-Marie; Stellenbosch University. Faculty of Arts and Social Sciences. Dept. of Psychology.
Attachment theory aims to provide a general theory of personality development. Attachment research has a responsibility to investigate the correlation between childhood attachment, adult attachment, aspects of personality development and psychopathology. The purpose of this literature review is to provide the reader with a summary, and critique of current research and knowledge on parent-child attachment - with a particular emphasis on the development of disorganized attachment in infancy and its connection to the development of Borderline Personality disorder. In this paper, essential propositions from attachment theory regarding the complex relation between early experience and psychopathology will be elaborated. These include formulations concerning (i) Disorganized attachment and psychopathology with a specific focus on Borderline Personality disorder (BPD); (ii) The correlation between BPD and disorganized attachment; (iii) Attachment theory and its implications; (iii) Causes of disorganized attachment and the role of early experience on later functioning and, (iv) implications for treating BPD patients. This literature review aims to stimulate future research on the predictive validity of attachment disorganization with relevance to the treatment of Borderline Personality Disorder.
Enkele faktore wat die formulering van voertaalbeleidsrigtings ten opsigte van die onderwys in veeltalige situasies beinvloed met spesifieke verwysing na Namibie
(Stellenbosch : Stellenbosch University, 1999) Hammond, Ashley Brandon; van der Merwe, G. S.; Stellenbosch University. Faculty of Arts and Social Sciences. Dept. of African Languages.
This assignment focuses on various factors that have a bearing on the formulation of a language policy for schools in Namibia. It is asserted that the ethnic and linguistic heterogeneity of the Namibian population combined with the lack of adequate research into the socio-linguistic features of the indigenous languages pose a grave impediment to this venture. This situation is further compounded by the highly politicised interpretation of the available data. Hence the first chapter is devoted to an explanation of relevant concepts against the backdrop of the Namibian context. The assignment then proceeds to investigate the decisive impact of local language attitudes in the engineering of a language policy. By means of several case studies it is firstly revealed that language attitudes are subject to periodisation. Secondly it is shown that the vernacular languages of Namibia are generally perceived in a negative way. This attitude, it is argued, also applies to Afrikaans which currently still functions as the lingua franca in the better part of the country. In the same vein it is attested that an inclination towards English is discernible among especially the economically productive and politically progressive sectors of the population. The opinion is advanced that this propensity towards English stems from the misplaced and purported association of Afrikaans with apartheid which was the official policy of the Afrikaans speaking white ruling minority until the attainment of independence in 1990. The subsequent historical survey of language policies during colonial times indeed reflects that indigenous languages have been grossly ignored by the South African authorities during their occupation of Namibia. Instead, Afrikaans was promoted at the expense of the Bantu and Khoisan languages of Namibia. It therefore came as no surprise that the new democratic government sought to curtail the use of Afrikaans in the education system by depriving it of its official status. Slavishly following the recommendations of the UNIN Report, English was hastily implemented as the sole official language. Ironically, careful scrutiny of the new language policy betrays that a rather subordinate role has been assigned to the indigenous languages which is nothing but a continued disservice to the Namibian child and a perpetuation of past imbalances in the formal education system. The validity of psycholinguistic arguments in favour of the extension and expansion of mother tongue instruction has been grossly discarded by the policy-makers. Serious objections can thus be raised against the immersion policy according to which the new language of instruction was implemented shortly after independence. Not only was "immersing at full speed" the order of the day but the cycle of implementation had only been conducted once. Hence it is strongly recommended that an alternative model of implementation (Appendix 3) be introduced. This implementation cycle will stretch over six years (Grade 4 - Grade 9) and is aimed at affording the indigenous languages their proper place in the classroom as is provided for in Article 3 of the Namibian Constitution.
Flood frequency analysis – Part 2: Development of a modified plotting position
(South African Water Research Commission., 2022-04-27) Van der Spuy D; Du Plessis JA
The original plotting position concept was suggested more than a century ago. Since then, many alternative plotting position approaches have been developed. Despite a general lack of agreement around which plotting position is theoretically ‘correct’ and the ‘best’ to use, all plotting positions fail to adequately address outliers and data of similar magnitude. Hydrologists generally fail to acknowledge that the plotting position primarily offers an informative display of data, against which distributions can be compared, rather than an absolute measure of probability. This paper does not intend to challenge any of the many lengthy theoretical mathematical arguments, utilised to ‘prove’ why one plotting position is superior to the others. These theoretical arguments may very well be valid for a ‘population’ of flood peaks – the reality, however, is that hydrologists are confronted with the challenge of analysing very limited ‘samples’ of the population. Consequently, the plotting position issue demands a more pragmatic approach, rather than a purely theoretical approach. This paper illustrates various problems with existing plotting position techniques in use and offers an alternative approach and a more sensible plotting position technique, using Z-scores and referred to as the Z-set PP, against which distributions can be checked. The study further illustrates how effectively the Z‑set PP deals with outliers and its robustness with various record lengths. Although derived from a study of flood peak data obtained from South African flow-gauging sites, it is deemed that it will be universally applicable.
INH preventive therapy (IPT) in HIV-infected south African children
(AOSIS, 2011) Cotton, Mark F.
HIV-infected children have a high risk of acquiring tuberculosis. The World Health Organization (WHO) has released isoniazid preventive therapy (IPT) recommendations for adults and children living with HIV, based on efficacy studies, mainly in adults. Data from children appear conflicting. IPT guidelines for children were developed in response to WHO guidelines at a local meeting, followed by discussions. IPT should be given to all HIV-infected children after exposure to a source case if treatment for active disease is not required. For children whose mothers' HIV status was known antentally, when tuberculosis has been actively excluded in mothers and at infant follow-up, and when infants have commenced antiretroviral therapy in the first 3 months of life, IPT is not required. Otherwise, all infants and children should be given IPT for 6 months once active tuberculosis has been excluded.
Investigating the role of a novel protein in iron–sulphur cluster biogenesis in mycobacteria
(2020-11-17) Niemand, Nandi; Williams, Monique; Warren, Robin; Weber, Brandon
A novel method (FotoMaster) of documenting endosocopic surgical procedures
(Elsevier, 2000) Kruger, Thinus F.; Van der Merwe, Jacobus P.; Marino, Horacio; Hoogendijk, Christiaan F.; Du Toit, Thomas C.
'n Oorsig van die bepaling van die vroeë bakterisidiese aktiwiteit van verskeie antituberkilosemiddels
(AOSIS, 2003) Donald, P. R.; Sirgel, F. A.; Venter, A.; Fourie, P. B.; Parkin, D. P.; Seifart, H. I.; Van de Wal, B. W.; Maritz, J. S.
The early bactericidal activity (EBA) of an antituberculosis agent is the daily decline in log10 colony forming units of M tuberculosis per ml of sputum during the first two days of treatment with the agent. It reflects the capacity of an agent to kill the actively metabolising organisms in tuberculosis lung cavities. It offers a relatively cheap means to evaluate the antituberculosis activity of an agent in a small group of patients within a matter of months. This article summarizes the authors’ experience in seven published EBA studies and identifies sources of variation in the procedure. The patients who participated in these studies had a mean age of 33 years, a mean weight of 50 kg and there was extensive or massive involvement of the lungs in 55% of patients. The highest EBA values (0,50-0,66) were found in groups of patients receiving isoniazid and the lowest values (0,05 and 0,09 respectively), in patients receiving the aminoglycosides amikacin and paromomycin in a dose of 15 mg/kg body weight. The variation in EBA in 248 patients was 0,0312 and the variation ascribable to the process of sputum production and collection was 0,0233. This implies that the different aspects of sputum production and collection involved in obtaining a representative sputum sample are responsible for most of the variation in EBA results. The selection of patients for inclusion in EBA studies and their ability to co-operate in producing a representative sputum specimen are of critical importance in the successful completion of EBA studies.
Oxidative Organic Transformations Using Catalyst Systems Based on Metal Nanoparticles Supported on Organic/Inorganic Composite Materials
(2020-10-20) Storm, Ené; Mapolie, Selwyn Frank; Malgas-Enus, Rehana
Pathology-supported genetic testing presents opportunities for improved disability outcomes in multiple sclerosis
(2023-05-17) Johannes, Clint; Moremi, Kelebogile E.; Kemp, Merlisa C.; Whati, Lindiwe; Engel- Hills, Penelope; Kidd, Martin; van Toorn, Ronald; Jaftha, Mariaan; Janse van Rensburg, Susan; Kotze, Maritha J.
Background: Lipid metabolism may impact disability in people with multiple sclerosis (pwMS). Methods: Fifty-one pwMS entered an ultrasound and MRI study, of whom 19 had followed a pathology- supported genetic testing program for more than 10 years (pwMS-ON). Genetic variation, blood biochemistry, vascular blood flow velocities, diet and exercise were investigated. Results: PwMS-ON had significantly lower (p < 0.01) disability (Expanded Disability Status Scale) than pwMS not on the program (1.91 ± 0.75 vs 3.87 ± 2.32). A genetic variant in the lipid transporter FABP2 gene (rs1799883; 2445G>A, A54T) was significantly associated (p < 0.01) with disability in pwMS not on the program, but not in pwMS-ON (p = 0.88). Vascular blood flow velocities were lower in the presence of the A-allele. Conclusion: Pathology-supported genetic testing may provide guidance for lifestyle interventions with a significant impact on improved disability in pwMS. Plain Language Summary This study investigated the role of a genetic variant that increases saturated fat absorption and may make people with multiple sclerosis (MS) more susceptible to disability progression. Of 51 people with MS, 19 had followed a program which includes normalization of blood test results and daily intake of unsaturated fatty acids for more than 10 years, while the others had not. The latter group had significantly greater disability than the people who had followed the program, suggesting that the unsaturated fatty acids modulated the effect of the genetic variant. Six MS cases are presented as examples, including a marathon athlete (Case 1) and a patient who showed a dramatic decrease in disability from being wheelchair-bound for 15 years to walking freely (Case 2). Executive Summary: • In order to investigate the conundrum of why some people with multiple sclerosis (pwMS) become disabled while others do not, a cross-sectional interdisciplinary study was initiated from 1996 to the present at Stellenbosch University, to record data into a database regarding genetic variations, blood biochemistry, diet and exercise. Pathology-supported genetic testing (PSGT), a practical method to apply personalized medicine, was implemented to elucidate potential modulation of genetic variations through lifestyle interventions toward prevention of disability in pwMS. • The Gknowmix.org database is used to translate information obtained from a comprehensive study into personalized reports containing guidelines for treatment of pwMS by clinicians and supporting healthcare professionals, which enables P4 medicine: participatory (patient), personalized (scientist), predictive (clinician) and preventive (dietitian). • In the present case–control sub-study, 51 pwMS and 25 controls volunteered for an ultrasound and MRI study. Of these pwMS, 19 had followed the PSGT lifestyle program for more than 10 years, which included normalization of blood biochemistry, dietary intervention and exercise, as well as daily intake of specific supplements (the Rapha Regimen) [3], including unsaturated fatty acids (omega-3 and evening primrose oil). • The 19 pwMS who had followed the program had significantly less disability (p < 0.01), as assessed with the Expanded disability status scale (EDSS), than those who had not followed the program (1.91 ± 0.75 vs 3.87 ± 2.32). Furthermore, in the pwMS who had not followed the program, a genetic variant of a lipid transporter which favors increased absorption of saturated fatty acids, FABP2 rs1799883 (2445G>A, A54T), was associated significantly (p < 0.01) with the EDSS, while in the pwMS who had followed the program there was no association (p = 0.88). There was no difference in allele frequency between pwMS and controls. • Ultrasound assessments showed that higher blood flow velocities in the right common carotid arteries and vertebral arteries were significantly associated with improved EDSS, while the FABP2 rs1799883 variant was associated with decreased blood flow. • In the pwMS, homocysteine was significantly inversely associated with folate intake (p < 0.01). In the controls, saturated/trans fat intake was significantly associated with BMI (p < 0.01). • Six MS cases selected randomly are presented to demonstrate how data integration was instrumental in elucidating how dietary unsaturated fat intake may modulate the effect of FABP2 rs1799883 toward prevention of disability in pwMS who followed the PSGT protocol over more than 10 years. Of these, Case 1 is a marathon athlete, and Case 2 showed a dramatic decrease in EDSS from 7.5 to 2.0 over more than 10 years.
The radiation characteristics of microwave antennas using the planar near-field measurement technique
(Stellenbosch : Stellenbosch University, 1992) Botha, Jeandre; Cloete, J. H.; Palmer, K. D.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
The thesis deals with the metrology and diagnosis of microwave antennas using probe-corrected planar near-field measurement technique. The theoretical formulation of the measurement technique, according to the Plane Wave Scattering Matrix formulation of Kerns [1], was implemented to obtain expressions for the radiation characteristics of an antenna. The representative antenna usen in the planar near-field measurements was an 8 x 8 element circularly polarized microstrip antenna array [2].
Rehabilitation and primary care treatment guidelines, South Africa
(World Health Organization, 2022-08-22) Conradie, Thandi; Charumbira, Maria; Bezuidenhout, Maryke; Leong, Trudy; Louw, Quinette
The World Health Organization recognizes rehabilitation as an essential component of universal health coverage (UHC). In many countries, UHC builds on a standard benefits package of services that is informed by the country’s essential medicines list, standard treatment guidelines and primary health care essential laboratory list. In South Africa, primary health care is largely provided and managed by primary health-care nurses and medical officers in accordance with primary health care standard treatment guidelines. However, rehabilitation is mostly excluded from these guidelines. This paper describes the 10-year process that led to rehabilitation referral recommendations being considered for inclusion in South Africa’s primary health care standard treatment guidelines. There were five key events: (i) a breakthrough moment; (ii) producing a scientific evidence synthesis and formulating recommendations; (iii) presenting recommendations to the national essential medicines list committee; (iv) mapping rehabilitation recommendations onto relevant treatment guideline sections; and (v) submitting revised recommendations to the committee for final consideration. The main lesson learnt is that, by working together, rehabilitation professionals can be of sufficient number to make a difference, improve service delivery and increase referrals to rehabilitation from primary health care. A remaining challenge is the lack of a rehabilitation representative on the national essential medicines list committee, which could hamper understanding of rehabilitation and of the complexities of the supporting evidence.
Die Sastech bestuursinligtingstelsel : 'n verkennende studie wat lei tot 'n konseptuele totale stelsel
(Stellenbosch : Stellenbosch University, 1991) Botha, Jacques Paul; Viviers, F.; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.
Sastech Engineering Services (Secunda) is part of the Sasol Group of Companies. It supplies highly specialized engineering and consulting services to the other companies within the Group. The prime functions of the company include: Project Management, Consulting Services, Engineering Design, (Process, Mechanical, Electrical, Control Systems and Civil) as well as the transfer of technology. Due to the nature of Sastech's work, large amounts of information flow within the organisation, as well as to and from suppliers and clients. In the area of Project Management it is especially important that responsible persons receive accurate and timely information to ensure that projects are completed on time and within budget. The aim of this study is to define and understand the concepts of Information, Systems, Management and Information Systems. Furthermore, the aims, procedures, organisation structure and systems of Sastech Engineering Services are studied and documented. Lastly follows a rough design phase that aim to identify the required subsystems and develop a conceptual total system as well as a plan to implement it at Sastech.

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