This practice of traditional male circumcision among the Xhosa people in the Eastern Cape Province of South Africa is accompanied by a high level of secrecy: details of the practice may not be shared with non-members such as women, uninitiated boys and strangers. To address the issue of injuries and deaths resulting from poorly performed unhygienic circumcision by untrained practitioners, the Department of Public Health in the Eastern Cape passed the Application of Health Standards in Traditional Circumcision Act No 6 of 2001. In order to explore the conflicting interests between public health and custodians of indigenous knowledge of curation and dissemination of information about Xhosa initiation rites, sociocultural theory through a systematic review of literature is used. Meta-ethnography design and a qualitative research approach is also used, as well as NVivo 11 qualitative data analysis software to analyse the data. Eighteen databases were used, and searches were conducted on 9 June 2016 and 13 October 2018. Using the systematic review screening process and PRISMA checklist, articles were screened against inclusion criteria, resulting in nine articles being included in the final review. Apart from the aforementioned findings that the practice excludes non-members from participating and disseminating information, and that traditional practitioners lack basic skills and knowledge necessary for procedures, findings also showed that the establishment of the Circumcision Act was the major reason for the conflict that exists between public health and Xhosa people: Xhosa people do not want secret information about the practice to be disseminated to non-members. In conclusion it is recommended that the Xhosa-speaking community make some Traditional Male Circumcision (TMC) information available while still preserving the fundamental secret information for traditional purposes. For example, access to pertinent information should be given to public health officials to enable assistance in addressing botched circumcisions.

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<p> The polymerization of styrene initiated with gamma radiation as well as thermal initiation was studied at temperatures, 150, 155, 160, 165, 180 and 200C and dose rates of 0.072-0.1836 M Rads/hour. In all cases the reactions were studied up to 100% conversion and the following results were obtained. (1) Rate of polymerization was independent of dose rate. (2) 165C was considered to be the temperature at which the radiation polymerization system in the case of styrene reaches a limiting rate of initiation caused by high temperature and dose rate. (3) Self-production of ethynylbenzene in the system at 200C probably caused retardation of the initial rate of polymerization. (4) No significant gel effect was observed in the investigated temperature range. (5) Polystyrene produced by radiation at high temperatures has a very low average molecular weight. (6) A general mechanism was proposed based on the characteristics of the reactions. (7) A temperature range was proposed as an optimal reaction temperature for radiation polymerization of styrene. </p> / Thesis / Master of Engineering (MEngr)

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Enterococcus faecalis is a Gram-positive bacterial species that is typically a member of the human gastrointestinal tract microbiota. However, E. faecalis is also a nosocomial pathogen, which is involved in urinary tract infections, soft tissue infections and endocarditis. In recent times, the occurrence of antibiotic resistance has complicated the treatment of these infections. One of the major differences between commensal and pathogenic strains of E. faecalis is that pathogens contain multiple mobile elements such as plasmids, transposons and integrative conjugative elements (ICE). These elements allow for the acquisition and transfer of virulence factors and resistance genes. Conjugative plasmids are a class of plasmids present in E. faecalis whose transfer to host cells is induced by a small pheromone peptide, cCF10 (LVTLVFV). This peptide is initially encoded as a 22-amino acid precursor (pre-cCF10) from the signal sequence of the chromosomal ccfA gene and is then proteolytically cleaved by signal peptidase II and Eep. Once pCF10 has been transferred a host E. faecalis cell, it is exceptionally stable. A replicon clone is maintained in greater than 85% of host cells over 100 generations in the absence of selection, suggesting the stability of pCF10 is intrinsic to the replicon. Three unique features of the replication initiation protein PrgW may contribute to this stability: (a) the interaction of PrgW with pre-cCF10, (b) disulfide bond formation at three conserved cysteines (C78, C275, and C307) in PrgW, and (c) processing of the nascent PrgW protein. Replication initiation proteins associated with theta replicons, such as pCF10, are often self-contained units. To initiate plasmid replication, the replication initiation protein (PrgW) binds to direct repeats (oriV) in its own coding sequence (prgW). In silico analysis of PrgW suggests the existence of three distinct domains within the protein. The first 122 amino acids are homologous to a conserved domain present in related replication initiation proteins, which includes a Helix-Turn-Helix (HTH) DNA binding domain. This suggests that this domain of PrgW has a DNA-binding function and binds to the oriV site in prgW. The following 61 amino acids are not similar to any known sequence, and are encoded by the DNA sequence containing the direct repeats in the oriV site. This domain may or may not have a distinct function. The remaining sequence forms a domain that contains cysteines C275 and C307, and is also similar to no known structure. It is hypothesized that this domain is related to the stability of pCF10. C307 appears to be critical, as previous experiments indicate that its mutation alone affects plasmid stability. Secondary structure analysis of this domain revealed the presence of multiple alpha-helices that contain distinct hydrophobic domains that possibly contribute to pre-cCF10 binding and PrgW tertiary structure. The positions of the conserved cysteines within these alpha-helices may stabilize a hydrophobic binding pocket that could potentially facilitate interaction with pre-cCF10. PrgW has a predicted molecular weight of 38.6 KDa and can be detected in Western blots as a band with an apparent approximate molecular weight (mw) of 36,000. Previous data from our lab indicates that, when overexpressed in E. faecalis, four bands of PrgW are present with observed molecular weights of 40,000, 36,000, 24,000 and 18,000. Time course experiments revealed that the 40,000 mw form is converted to a 36,000 mw form independent. The 40,000 mw form is unstable (with a complete turnover in 30 minutes) while the 36,000 mw form has a half-life of greater than 4 hours. The 24,000 mw band does not have a DNA binding motif and is likely a turnover product. When the three conserved cysteines (and only cysteines) in PrgW are replaced with alanine, the 40,000 mw form is still processed to the 36,000 mw form. However, the cysteine to alanine mutants accumulate the 36,000 mw form. / Microbiology and Immunology

The Session Initiation Protocol (SIP) was first published in 1999, by the Internet Engineering Task Force (IETF), to be the standard for multimedia transfers. SIP is a peer-to-peer signaling protocol that is capable of initiating, modifying, and terminating media sessions. SIP utilizes existing Internet Protocols (IP) such as Domain Name Service (DNS) and the Session Description Protocol (SDP), allowing it to seamlessly integrate into existing IP networks. As SIP has matured and gained acceptance, its deficiencies when functioning as a multipoint communications protocol have become apparent. SIP currently supports two modes of operation referred to as conferencing and multicasting. Conferencing is the unicast transmission of session information between conference members. Multicasting uses IP multicast to distribute session information. This thesis proposes an extension for the Session Initiation Protocol that improves functionality for multipoint communications. When using conferencing, a SIP user-agent has limited information about the conference it is taking part in. This extension increases the awareness of a SIP node by providing it with complete conference membership information, the ability to detect neighboring node failures, and the ability to automatically repair conference partitions. Signaling for conferencing was defined and integrated into a standard SIP implementation where it was used to demonstrate the above capabilities. Using a prototype implementation, the additional functionality was shown to come at the cost of a modest increase in transaction message size and processing complexity. IP multicast has limited deployment in today's networks reducing the usability of this useful feature. Since IP multicast support is not guaranteed, the use of application layer multicast protocols is proposed to replace the use of IP multicast. An efficient means of negotiating an application layer protocol is proposed as well as the ability to provide the protocol with session information to begin operation. A ring protocol was defined and implemented using the proposed extension. Performance testing revealed that the application layer protocol had slightly higher processing complexity than conferencing, but on average had a smaller transaction message size. / Master of Science

Translation is the biological process that ultimately leads to the synthesis of a protein from the genetic material mRNA. Protein synthesis is essential for life as we know it, which is rooted in its extreme conservation throughout all living organisms. Translation is typically divided into four phases, the first of which, denominated translation initiation, is the most delicate step, as it entails the determining the correct start site of the produced protein. Previous structural studies allowed us to gain important insights into the position of translation Initiation Factors, and their function during the formation of the bacterial Initiation Complex and the proper positioning of the initiator tRNA on the start codon of the mRNA. Nevertheless, the limited resolution of the structures hampered gaining a pristine view of the molecular details that are essential for the correct assembly of this important step of translation. Moreover, little information is available regarding the differences underlying the initiation of translation on non-canonical start codons. Driven by recent improvements in cryo-EM, this work aims to fill these gaps and shed molecular insights into bacterial initiation of translation. This work further highlights for the first time, at molecular resolution, multiple important interactions that occurs between the 30S subunit, mRNA, initiator tRNA and initiation factors during the process of Initiation Complex formation. Supported by the structural data obtained, a new model for the order of initiation complex assembly is suggested. The model presented underlines the complexity of bacterial initiation of translation and paves the way for future experiments to gain a holistic view of this step of translation.