Magister Public Health - MPH / Background: First line regimens give patients the best chance of long-term treatment success. It is imperative that patients stay on their original first line regimens to ensure program viability. As the ART programme matures in Namibia the proportion of patients who have had their first line regimens modified continues to increase. It is estimated that 3.1% of adults in Namibia are on second line regimens. Second line or other modified regimens are generally reserved for clinical, immunological or virological failure and toxicity related complications. These modified regimens often involve a higher pill burden, more toxicities and are often more expensive. A more detailed understanding of the factors associated with first line regimen modification could allow healthcare providers in Namibia to target these factors for intervention to reduce regimen modification and improve treatment outcomes. Methodology: This quantitative descriptive retrospective cohort study sought to describe factors associated with first line HAART regimen modification in treatment naïve adult patients who started HAART at Gobabis State Hospital between 1st January 2007 and 31st December 2010. Utilizing data from an existing electronic patient management system, quantitative methods were used to assess the prevalence, reasons and factors associated with first line HAART regimen modification. Results: The prevalence of HAART regimen modification was 14.1%. Treatment toxicity was the major reason (35%) for HAART regimen modification and this was largely due to D4T containing regimens. This was followed by treatment modification due to concurrent TB disease (27.3%), new drug availability (19%), pregnancy (6.6%) and virological failure (2%). A death rate of 9% was recorded by the end of the study period in each of the two groups, of those who had their first line HAART regimen modified and those who remained on original regimens respectively. There were statistically significant associations between regimen modification and type of regimen, care entry point, duration from HIV diagnosis to entry into HIV care, sex and functional status. Regimen modifications resulted in more AZT and TDF based regimes while 88.7% of patients had D4T taken off their HAART regimens. Conclusions: HAART regimen modification at Gobabis State hospital is lower than in other settings was largely due to treatment toxicity. The death rate is high and warrants further exploration. Regimen modifications resulted in more AZT and TDF based regimes and more patients had D4T taken off their HAART regimens. Recommendations: Patients still on D4T need close monitoring for side effects associated with this drug and should be promptly changed if this is the case. This study raises the important programmatic issue of the need for good data collection practices. HIV positive patients who are pregnant and those with concurrent TB disease need close monitoring to ensure that HAART regimens are modified appropriately.

Detonation waves are supersonic combustion waves that have a complex three-dimensional cellular structure. There is growing experimental evidence that the cellular structure of detonations promotes their propagation in the presence of losses. In spite of that, the conventional model for the detonation structure, known as the Zeldovich - Von Neumann - Doring (ZND) model, neglects the existence of cellular structure for detonations and assumes the wave to consist of a strong leading planar shock coupled with trailing chemical reactions. Therefore, the influence of cellular structure on the dynamics and extinction limits of detonation waves has been of particular interest. Previous studies have investigated the influence of cellular structure on the dynamics of detonations with mass divergence in the framework of narrow tubes, porous-walled tubes and weak confinement. However, precise quantification of the loss mechanism in these frameworks has been associated with some difficulties. Complex flow in the boundary layers, inherent in thin tubes, or attenuation of the transverse waves in the porous-walled tubes has made the evaluation of the loss mechanism more difficult in such geometries. In this thesis, a novel well-posed problem is formulated for detonations with mass divergence. It is shown that detonations propagating in a channel with a cross-section area increasing exponentially have a constant mass divergence. The detonations were found to propagate at a quasi-steady speed below the ideal Chapman-Jouguet velocity. This permitted to make meaningful comparison with the theoretical models and simulations. The experiments were performed in two mixtures, one displaying characteristic weakly unstable detonations (2C2H2 + 5O2 + 21Ar), and the other displaying highly unstable detonations (C3H8 + 5O2). The dependence of the velocity deficits and limits on the amount of mass divergence for the two mixtures were compared with the predictions of the quasi-one-dimensional ZND model with lateral mass divergence. Since the ZND model neglects the cellular structure of the detonations, such comparison permitted to asses the influence of cellular structure on the dynamics of detonations with mass divergence. Comparisons were also made with the results of simulations of inviscid cellular detonations. These comparisons showed that the velocity deficits and critical rate of mass divergence in the weakly unstable mixture were reasonably well predicted by the quasi-one-dimensional model. For smaller values of mass divergence rate, a good agreement between the experiments and the predictions of the two-dimensional cellular simulations was observed for the weakly unstable mixture. For the highly unstable detonations, the quasi-one-dimensional model significantly over-predicted the effect of mass divergence.Detonations were observed for rates of mass divergence 93% higher than the critical predicted value, displaying more substantial velocity deficits than predicted. Such observations show conclusively that the ZND model cannot capture the dynamics of highly unstable detonations on large scales.

No description available.

On-orbit targeting, guidance, and navigation relies on state vector propagation algorithms that must strike a balance between accuracy and computational efficiency. To better understand this balance, the relative position accuracy and computational requirements of numerical and analytical propagation methods are analyzed for a variety of orbits. For numerical propagation, several differential equation formulations (Cowell, Encke-time, Encke-beta, and Equinoctial Elements) are compared over a range of integration step sizes for a given set of perturbations and numerical integration methods. This comparison is repeated for two numerical integrators: a Runge-Kutta 4th order and a NLZD4/4. For analytical propagation, SGP4, which relies on mean orbital elements, is compared for element sets averaged with different amounts of orbit data.

A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of MSc (Med) Johannesburg, 2011 / Peripheral sensory neuropathy is a common neurological complication of antiretroviral therapy, typically occurring within 6-months of starting Highly Active Antiretroviral Therapy (HAART) which includes stavudine. Therefore, the primary aim of the study was to determine the 6-month incidence of ATN in patients free of neuropathy and beginning stavudine-based HAART for the first time. Also, we examined whether initiating stavudine-based HAART altered the symptoms of patients who had a pre-existing, virus-mediated distal symmetrical polyneuropathy (HIV-DSP). Seventy-five HIV-positive patients were screened for neuropathy, at the Chris-Hani Baragwanath Hospital, using the AIDS Clinical Trials Group neuropathy screening tool. The bilateral presence of atleast one sign (decreased vibration sense in the great toe or absent ankle reflex) and one symptom (pain, paraesthesia or numbness) in the feet was indicative of neuropathy. On recruitment, 52 patients presented without neuropathy and 13 patients presented with HIV-DSP. After 3- months of follow-up (n=46), 23% (10/46) of patients had developed peripheral neuropathy, and by 6-months (n=44), 41% (18/44) of patients had developed neuropathy. Greater disease severity was the only risk factor significantly associated with the development of neuropathy. Eleven (61%) of the 18 patients that developed neuropathy, developed painful symptomatic neuropathy, and only 6 (55%) of these patients were receiving treatment for symptom relief. In patients with HIV-DSP, numbness was the most common symptom reported at baseline and was the only symptom to reduce in frequency across the 6-months. In conclusion, we found that the development of neuropathy is common in the first 6-months of patients initiating stavudine-based HAART.

The Human Immunodeficiency Virus (HIV) which causes Acquired Immunodeficiency Syndrome (AIDS) has caused a global scare with mainly poor African countries suffering the greatest burden. Treatment of HIV is more of palliation rather than cure such that there is no room for treatment interruption if treatment goals are to be met. Antiretroviral treatment is associated with short term and long term side effects which have the potential to negatively impact on the high levels of adherence to treatment that is required to maintain virological suppression and may eventually lead to development of drug resistance and treatment failure. This research aims to identify the extent to which these side effects, through possible poor adherence, impact on treatment successes by measuring the risk that side effects contribute towards treatment failure. Methods Secondary data analysis was conducted on a cohort of patients who initiated ART between 2004 and 2010 at a large tertiary facility in Johannesburg. Patients who were switched to second line ART due to treatment failure were identified. Assessment of side effects on adherence was done. The hazards of side effects among patients switching and not switching to second line were calculated using Cox proportional hazards regression adjusting for other socio-demographic and clinical predictors for treatment failure. Interaction between side effects, gender, age and that of side effects and adherence was investigated. Time dependent covariates were also investigated. Confounding was controlled using multivariate Cox regression analysis. Results There were 5285 patients in the baseline cohort with multiple entry points who contributed 16035 person-years of follow up. The cohort consisted of 63.2% females and 36.8% males. Of these 85.9% were initiated on stavudine (d4T)- based regimen, 7.1% on tenofovir (TDF), 6.3% on zidovudine (AZT)-based regimen and 0.7% on other regimens. The median and mean time at risk per subject was 2.2 and 2.3 years respectively. A total of 770 episodes of side effects due to first line ART were experienced with some patients recording multiple side effects at different time points. Adherence data were found to be missing and incoherent in some of the regimen dosages and could not be used to objectively compare patients. There were 430 patients who were switched to second line ART due to treatment failure. Relative to the group of no side effects, the adjusted hazard ratios for mild, moderate and severe side effects were 1.40 (95% CI=0.94-2.09) p=0.10; 1.72 (95% CI=1.35-2.20) p<0.01 and 1.24 (95% CI=0.65-2.35) p=0.52 respectively. Therefore, overally side effects did not seem to play a role in the time to switch to second line ART. Sex, baseline CD4 cell count, the period during which ART was initiated and the time between date of testing HIV positive and date of initiating were significantly associated with the time to switching to second line ART. Conclusion The study informs that side effects overally may not play a significant role in switching patients from first line to second line ART with the exception of moderate side effects. However, patients who experience side effects should be closely monitored and adequately counselled to help them cope with the side effects so that optimal adherence levels are maintained. Availability of adherence scores or additional information on pills that should have been taken on periods during which pills were reported to have been missed would have made the research more valuable by allowing objective comparison of adherence among patients.

The roll-out of antiretroviral drugs in South Africa started in March 2004. In Mopani district, a rural district of Limpopo Province, the roll-out programme commenced in October 2004. While many resources were invested in this program, no study has assessed the clinical outcomes in this rural district. In addition, most studies conducted in South Africa were conducted in urban and tertiary settings. Assessing clinical outcomes is important in determining whether the program is making the desired clinical difference in the lives of the patients and may serve as feedback into the program for quality improvement purposes. Methodology The study was a retrospective record review of patients who were initiated on antiretroviral (ARV) treatment between December 2007 and November 2008. A structured questionnaire was used to collect data from 124 patient’s files and data was collected up to November 2011. The data collected included patients’ socio-demographic characteristics, clinical outcomes (CD4 count, viral load, presence of opportunistic infections, adverse effects and hospital admissions recorded at 6, 12, 24 and 36 months), the number of patients who were still attending the ARV clinic at 36 months and the reasons why patients are no longer attending the clinic. Data was analysed with Epi-Info and STATA. Results Of the 124 patients, 69% were females, 28% males and 3% did not have their sex specified. The majority of the patients were between 30 and 49 years. There was a significant improvement in CD4 count and viral load between baseline and all timeperiods after the initiation of ARV treatment. The mean CD4 count at baseline was 128The roll-out of antiretroviral drugs in South Africa started in March 2004. In Mopani district, a rural district of Limpopo Province, the roll-out programme commenced in October 2004. While many resources were invested in this program, no study has assessed the clinical outcomes in this rural district. In addition, most studies conducted in South Africa were conducted in urban and tertiary settings. Assessing clinical outcomes is important in determining whether the program is making the desired clinical difference in the lives of the patients and may serve as feedback into the program for quality improvement purposes. Methodology The study was a retrospective record review of patients who were initiated on antiretroviral (ARV) treatment between December 2007 and November 2008. A structured questionnaire was used to collect data from 124 patient’s files and data was collected up to November 2011. The data collected included patients’ socio-demographic characteristics, clinical outcomes (CD4 count, viral load, presence of opportunistic infections, adverse effects and hospital admissions recorded at 6, 12, 24 and 36 months), the number of patients who were still attending the ARV clinic at 36 months and the reasons why patients are no longer attending the clinic. Data was analysed with Epi-Info and STATA. Results Of the 124 patients, 69% were females, 28% males and 3% did not have their sex specified. The majority of the patients were between 30 and 49 years. There was a significant improvement in CD4 count and viral load between baseline and all timeperiods after the initiation of ARV treatment. The mean CD4 count at baseline was 128 The roll-out of antiretroviral drugs in South Africa started in March 2004. In Mopani district, a rural district of Limpopo Province, the roll-out programme commenced in October 2004. While many resources were invested in this program, no study has assessed the clinical outcomes in this rural district. In addition, most studies conducted in South Africa were conducted in urban and tertiary settings. Assessing clinical outcomes is important in determining whether the program is making the desired clinical difference in the lives of the patients and may serve as feedback into the program for quality improvement purposes. Methodology The study was a retrospective record review of patients who were initiated on antiretroviral (ARV) treatment between December 2007 and November 2008. A structured questionnaire was used to collect data from 124 patient’s files and data was collected up to November 2011. The data collected included patients’ socio-demographic characteristics, clinical outcomes (CD4 count, viral load, presence of opportunistic infections, adverse effects and hospital admissions recorded at 6, 12, 24 and 36 months), the number of patients who were still attending the ARV clinic at 36 months and the reasons why patients are no longer attending the clinic. Data was analysed with Epi-Info and STATA. Results Of the 124 patients, 69% were females, 28% males and 3% did not have their sex specified. The majority of the patients were between 30 and 49 years. There was a significant improvement in CD4 count and viral load between baseline and all timeperiods after the initiation of ARV treatment. The mean CD4 count at baseline was 128 cells/mm3; it increased to 310 cells/mm3 at 6 months, 380 cells/mm3 at 12 months and 470 cells/mm3 at 24 months. By 6 months, 67% of the patients had achieved viral suppression, but at 24 months, patients started having viral rebound. During the study, 20 patients fell pregnant and four patients fell pregnant twice. Overall, pregnant patients had a significantly higher viral load compared to non-pregnant patients (p-values = 0.015 at 6 months, 0.002 at 12 months and 0.027 at 24 months). Seventy two percent of patients were retained in the program at 36 months. Of the 28% that were no longer attending the clinic, 11.3% were transferred to other institutions, 6.5% were down referred to clinics, 3.2% died, 3.2% defaulted and 3.2% were lost to follow-up. Conclusion This study shows that good clinical outcomes can be achieved within an antiretroviral rollout program in a rural hospital. The biggest magnitude of clinical benefits was observed in the first six months after the initiation of ARV treatment with threats of viral rebound thereafter. There was good patient retention at 36 months after initiation of ARV treatment and a significant difference in viral load between pregnant and non-pregnant patients. The high rate of unplanned pregnancy signifies the need to place closer attention to family planning among female patients on antiretroviral treatment.

Carcinoma of the cervix is frequently diagnosed in the department of Radiation Oncology in Charlotte Maxeke Johannesburg Academic Hospital(CMJAH). It is therefore is a condition of priority and there is scarce literature in the management of HIV positive patients. OBJECTIVES: The primary objective of the research is to determine the overall survival of 2yrs and more, as well as to determine acute and late toxicity for patients completing prescribed radiation treatment. The secondary objective was to determine the impact of highly active antiretroviral therapy on survival and toxicity. The study is limited to HIV positive women presenting with cervical cancer. DESIGN & METHOD: The study is a retrospective study of patients treated at Charlotte Maxeke Johannesburg Academic Hospital between 2008-2009. Inclusion criteria: Females between the ages of 18 and 70, Stages IB2 – Stage IIIB carcinoma of the cervix who have completed planned radiation therapy with or without chemotherapy. The sample size was 151 patients. RESULTS: The mean age was 42.7yrs. The median CD4 count was 309 and 26.2% had CD4 counts below 200.The majority of patients had either Stage IIB (55.0%) or IIIB (31.8%). The total dose to Point A was a median dose of 74Gy. The majority of patients had either Grade II (38.4%) or III (31.1%) toxicity. Significant association between these adverse events and HAART status was rated as p=0.0008. The most common late complication was cystitis (15.9%). Overall survival at 2 years was 100% for Stage I, 92.8% for Stage II and 96% for Stage III. CONCLUSION: The median age was lower than in the HIV negative patients. The acute complications for those not on HAART, were higher in comparison to patients on HAART. The overall survival at 2 yrs. was above 90% for all stages in this study / GR2018

No description available.

Masters of Commerce / Highly enriched uranium (HEU) is one of the most dangerous materials in the world, because it is a key ingredient in making a nuclear bomb. If a terrorist organisation can get HEU, it would be close to making a nuclear bomb. After South Africa disarmed its nuclear weapons, it kept HEU that was extracted from the nuclear bombs. The US tried to persuade South Africa to blend down its HEU into low enriched uranium (LEU) or give it up for safekeeping. However, South Africa refused to give it up. After a breach at Pelindaba, a national key point facility where South Africa stores its HEU, the US intensified its efforts to pressure South Africa to give its HEU up. It even promised incentives to South Africa should they agree to give it up, but South Africa refused. The US used the nuclear terrorism narrative to justify its initiative to eliminate vulnerable materials in the world. However, South Africa is yet to be swayed. This is odd since South Africa's refusal can negatively affect its credentials as a nuclear nonproliferation and disarmament champion and its image as a norm entrepreneur. The objective of the study was to understand the role played by HEU in South Africa's nuclear diplomacy. It was to explore HEU as a factor in the state's nuclear diplomacy and to understand the power of having HEU in nuclear negotiations, as well as what SA intends to do with its HEU. The study is framed theoretically by drawing on foreign policy theory, namely middle-power theory, and revisionism. It juxtaposed middle power, reformist, and revisionist positions with status quo foreign policy to analyse the role of HEU in South Africa's nuclear diplomacy. As a middle power with a moral high ground, South Africa hoped that it can affect change in the nuclear regime. However, when this did not occur its foreign policy shifted to a revisionist character that is discontent with the status quo in the nuclear regime. SA is dissatisfied with the current nuclear order and wants it revised towards liberal values such as equality and nondiscrimination. It views the current nuclear order as nuclear apartheid.