This paper presents the theory of weak primary decomposition of modules over a commutative ring. A generalization of the classic well-known theory of primary decomposition, weak primary decomposition is a consequence of the notions of weakly associated prime ideals and nearly nilpotent elements, which were introduced by N. Bourbaki. We begin by discussing basic facts about classic primary decomposition. Then we prove the results on weak primary decomposition, which are parallel to the classic case. Lastly, we define and generalize the Compatibility property of primary decomposition.

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Human herpes virus type 8 (HHV-8) is strongly implicated as the etiological agent of Kaposi’s sarcoma (KS). The incidence of KS in South Africa is increasing in parallel with the HIV-1 epidemic. Molecular and serological prevalence of HHV-8 in HIV-1 infected individuals with and without KS was investigated. DNA fragments from ORF26 (capsid, 330BAM233) and ORF75 (tegument) regions were used to determine the prevalence of HHV-8 DNA in peripheral blood mononuclear cells (PBMC) from 429 HIV-1 infected individuals, 95 of whom had histologically confirmed KS. Of those without KS, 14 (4.2%) were PGR positive for HHV-8 DNA. In the individuals with KS, the proportion of HHV-8 DNA positive PBMC samples was 11 times higher (46/95,48%). Similarly, an immunofluorescence assay showed that 78% of KS patients had antibodies to HHV-8 compared to 16% of KS negative individuals. Among the KS group, 93% of PCRpositive samples were also HHV-8 antibody positive compared to only 66% of PCR negative samples indicating that viremia is associated with good antibody responses. Matched lymph node and PBMC samples were available for 8 patients. HHV-8 DNA was more frequently detected in the lymph node (3/8) than in the blood (1/8), suggesting that the lymph nodes are a reser / o r for HHV-8. These data confirm the association between HHV-8 and KS and suggest that there is a high background prevalence of HHV-8 infection in HIV-1 infected individuals in South Africa. The ORP 75 gene of 40 HHV-8 strains was sequenced and the phylogenetic relationships between South African and already published sequences were investigated. The majority (n=29) of strains overlapped with the published A and B subgroups and were termed A/B variants.Three strains were classified as subgroup C while 8 sequences did not cluster with any of the previously classified subgroups and were termed novel (N) group. The DNA distance of this novel group differed from the A, B and C subgroups by 4.7%, 3.8% and 4,5% respectively although within the N group there was only 0.4% variation. The addition of this group significantly increased the number of subgroup-specific polymorphisms from 17 to 47 over a 804 bp region. There was sufficient inter-subgroup genetic diversity that single strand conformational polymorphisms (SSCP) could be used to rapidly identify them. Thus, based on the analysis of the ORF75 gene, a unique HHV-8 sub-group is present in South Africa which accounts for 20% of circulating strains. Further studies are required to determine the extent of evolutionary phytogeny, distribution and pathogenic potential of this novel group.

Thesis (M.Sc.(Dietetics))--University of Pretoria, 2009. / Abstract in English. Includes bibliographical references.

La littérature décrit des différences fondamentales entre l’AAV2 sauvage et ses pendants recombinants. La forme sauvage serait plus efficiente en terme de production, d’encapsidation et d’infectieusité, allant de facteurs de deux à cents en fonction de la propriété étudiée. A cause de ces différences, la quantité de rAAV nécessaire pour traiter un patient atteint d’une maladie implique une injection systémique estimée à 1.1015 particules par kilogramme de tissue à traiter. C’est dans cette optique que s’inscrivent mes travaux de thèse. Essayer de comprendre qu’elles sont les différences entre l’AAV sauvageet les rAAV qui peuvent engendrer tant de différences en terme d’efficacité. L’étude du comportement du génome de l’AAV2 sauvage dans le système baculovirus/cellules Sf9, a permis de découvrir que la régulation de l’AAV2 sauvage était similaire en baculovirus. Nous avons aussi découvert, grâce à notre analyse transcriptomique que les promoteurs naturels del’AAV2 étaient actifs dans notre système, ce qui nous a permis d’imaginer de nouvelles constructions génétiques afin d’améliorer la quantité et la qualité des particules rAAV. Nous avons aussi réaliser des études structurales sur différentesparticules AAV afin d’améliorer notre connaissance de ces particules. / The literature describes several fundamental differences between WT AAV and rAAP properties. WT form obtains an one hundred higher production yield compared to rAAV, with the possibility to obtain only full particles, and most importantly, all the WT AAV particles are infectious, compared to only 1% for the rAAV. These lower values for rAAV, implied to inject up to 1.1015 particles per kilogram of tissue. These quantities induce a non-negligible cost for rAAV based gene therapies, even with the productions techniques improvements or the development of baculoviruses based techniques. It is with these ideas in mind that my PhD works were developed. Trying to understand differences between WT and rAAV, trying to produce WT AAV in baculovirus has bring important knowledges about AAV comportment in baculovirus. Our RNA-Seq results have demonstrated than the WT AAV natural promoters were all active, allowing us to design to genetic constructs in order to improve rAAV quantity and quality. We have also tried to solve the AAV crystal structure, to improve our knowledges about these particles.

Surveillance of ventilator-associated pneumonia (VAP) has been the common outcome measurement used for internal and external benchmarking for mechanically ventilated patients; and although not a clinical definition, it is commonly used as an outcome measurement for research studies. Criteria in the VAP definition include both subjective and objective components, leading to questions of validity. In addition, recent legislation has mandated the public reporting of healthcare-associated infections, including VAP, in many states. Infectious disease experts have recently recommended monitoring a new outcome, ventilator-associated events (VAE), that contain specific objective criteria. The Centers for Disease Prevention and Control (CDC) have refined this definition and released a new VAE protocol and algorithm, replacing the VAP surveillance definition, as a result. The VAE protocol assesses for ventilatorassociated conditions (VAC). The primary aims of this study were to determine the incidence of VAC; and to assess four predictors for VAC, including two VAP prevention strategies (use of the subglottic secretion drainage endotracheal-tube [SSD-ETT]), and daily sedation vacation); and two patient-related factors (alcohol withdrawal during mechanical ventilation, and history of COPD). In addition, the incidence for VAE, using a new national algorithm was determined. Using a retrospective study design, electronic medical records of 280 veterans were reviewed to identify cases of VAC using the VAE algorithm. The setting was two intensive care units (ICU) at a large Veterans Administration Healthcare System (VAHCS) from October 2009 to September 2011. In addition to demographic information, variables were collected to determine if cases met event criteria (VAC, infection-related ventilator-associated complication iii [IVAC], and possible or probable VAP). Incidence rates were calculated for VAC and IVAC. Comparative data between those with and without VAC were assessed with independent sample T-test or non-parametric equivalents. The study sample was predominantly male (97.1%), Caucasian (92.1%), non-Hispanic (90.7%); with a mean (SD) age of 67.2 (10.4) years. Twenty patients met the VAC definition resulting in a VAC incidence of 7.38 per 1000 ventilator days. There were no statistically significant differences in demographics or disease characteristics found between the two groups (patients with VAC and patients without VAC). Using logistic regression, the impact of the four predictors for VAC was assessed. None of the four explanatory variables were predictive of the occurrence of VAC. Secondary outcomes (e.g. mechanical ventilation days, ICU days, hospital days, and mortality) of veterans with VAC were compared to veterans without VAC. Results indicated that the VAC group was associated with a significantly longer duration of ICU stay, longer mechanical ventilation period, more likely to have a tracheostomy, and had a higher mortality during hospitalization. Expanding mechanical ventilation quality performance measures to include VAE/VAC provides a better representation of infectious and non-infectious ventilator-associated problems, and provides more accurate morbidity and mortality in this high-risk ICU population. Further research is necessary to explore patient characteristics and prevention strategies that impact the development of all VAC.

Thesis (Ph. D.)--University of Virginia, 2008. / Includes bibliographical references. Also available online through Digital Dissertations.