Background: Street-involved youth are known to be at a greatly increased risk of HIV and sexually transmitted infections (STIs); however, the role that environmental and structural factors play in driving disease transmission risk among this population has not been thoroughly examined. Methods: The At Risk Youth Study (ARYS) is a prospective cohort of homeless and street-involved youth between the ages of 14 and 26. From September 2005 to October 2006, participants completed a baseline questionnaire which elicited information regarding sexual activity, injection and non-injection drug use, addiction treatment experience, encounters with police and security guards, and health service utilization. Environmental and structural correlates of number of recent sex partners were identified using quasi-Poisson regression. Factors independently associated with consistent condom use were also examined using logistic regression. Results: Among 529 participants, 415 (78.4%) were sexually active during the past six months, of whom 253 (61.0%) reported multiple sex partners and 288 (69.6%) reported inconsistent condom use during this time period. In multivariate logistic regression, homelessness and self-reported structural barriers to accessing health services were inversely associated with consistent condom use. In multivariate analysis, living in a shelter, hostel, or single room occupancy hotel was positively associated with greater numbers of recent sex partners. Structural factors that were associated with number of sex partners included having a warrant or area restriction that affects access to health services, and for males, being accosted by the police. Conclusions: Unstable housing, homelessness, and structural factors related to the criminalization and displacement of street-involved youth were associated with an increased risk of HIV and STI transmission, even after extensive adjustment for sociodemographic and individual level characteristics. These findings suggest that both environmental and structural factors influence the spread of HIV and STIs, and point to the need for environmental-structural interventions to reduce the burden of these diseases among this population. / Medicine, Faculty of / Population and Public Health (SPPH), School of / Graduate

The topic of the study is The Impact of HIV/AIDS and STIs in Secondary Schools in the Limpopo Province. The impact of HIV/AIDS and STDs on educators and learners in secondary schools is problematic. These epidemics are associated with an increase in absenteeism, requests for time off, emotional problems, changes in attitudes, overload on the side of teachers, unexpected deaths, increasing demands being made on medical aid schemes, as well as disability and malfunctioning of people and structures. The standard of education is deteriorating because of these diseases. Similarly, there is the need for managing the effects of these epidemics. This study employs participatory action research. The quantitative method is utilized in the study. The questionnaire is used as an instrument of measurement. The most important findings are as follows: • There is an increase in absenteeism for both learners and educators. • Learners’ performance is deteriorating. • Participation of learners in sport and extra-mural activities is decreasing. • Teachers’ productivity is deteriorating. • Depression is taking its toll both among learners and educators. • There is a high rate of dropouts. / Dr. M.C. van Loggerenberg

Background: Sexually transmitted diseases (STD's) have a major impact on sexual and reproductive health worldwide. Each year, the World Health Organization (WHO) estimates 448 million new cases of curable STD's are diagnosed. The emergence of drug resistance in STD related microorganisms and potential side effects demand the discovery of newer drugs. The exploration of newer anti-microbial substances from natural sources may serve as promising alternatives. In this study, twelve medicinal plant species used traditionally in the treatment of STD's are investigated in this regard. Methods: Ethanol plant extracts and three flavonoids were evaluated for their antimicrobial properties against one fungi and three bacteria, through the micro-dilution assay. To determine the anti-inflammatory activities of the extracts and compounds, the inhibitory effect was measured on the pro-inflammatory enzyme lipoxygenase, 15-LOX. Extracts were further evaluated for their inhibitory effect on the supercoiling activity of bacterial DNA gyrase by using the DNA gyrase kit. The extracts and compounds were lastly investigated for their anti-HIV activities against recombinant HIV-1 enzyme using non-radioactive HIV-RT colorimetric assay. Results: Acacia karroo and Rhoicissus tridentata extracts showed good antimicrobial activity with MIC values ranging between 0.4 and 3.1 mg/ml. Extracts of Jasminum fluminense, Solanum tomentosum and flavonoid 2 and 3 had good anti-inflammatory activity with IC50 less than the positive control quercetin (IC50 = 48.86 ug/ml). Extracts of Diospyros mespiliformis, Peltophorum africanum, Rhoicissus tridentata and flavonoids 1 and 2 showed the best inhibitory activity against the bacterial DNA gyrase. A. karroo and flavonoid 3 exhibited moderate HIV RT inhibition activity of 66.8 and 63.7 % respectively. R. tridentata and Terminalia sericea had the best RT inhibition activity (75.7 and 100 %) compared to the positive control doxorubicin (96.5%) at 100 ug/ml concentration. Conclusion: The observed activities may lead to new multi-target drugs against sexually transmitted diseases. / Dissertation (MSc)--University of Pretoria, 2017. / Plant Science / MSc / Unrestricted

MSc (Microbiology) / Department of Microbiology / Introduction: Intestinal infections caused by soil transmitted helminth and diarhoegenic Escherichia coli (E. coli) are a major threat to the health and socio-economic wellbeing of children in developing countries. Soil-transmitted helminthes (STH), Ascaris lumbricoides (A. lumbricoides), Trichuris tricuria (T. trichuris ), Hookworms and diarhogenic E coli are transmitted through the faecal-oral route and enter the body through the ingestion of eggs (STH) or E. coli pathogens following contact with contaminated hands, food, soil or the deliberate act of eating contaminated soil. Aim: This study aim to determine the prevalence of intestinal parasitic infection and diarhoegenic E. coli on the hands of school children in the Vhembe district of South Africa. Methods: The study was conducted among school children aged 5 to15 years, attending grades 0(R) to 8 at the primary and secondary school levels in the Vhembe district region of the Limpopo province. A total of 358 hand washing samples was collected from the hands of school children using hand anionic (7X 1% quadrafos, glycol ether and dioctyl sulfoccinate sodium salt) soap solution. The Microscopic McMaster slide technique was used for the identification of intestinal parasitic eggs and the Colilert Quanti-Tray®/2000 technique was used for the enumeration of E. coli. A standardised Multiplex PCR protocol was utilized to characterize the positive pathogenic E. coli strains obtained from the Colilert Quanti-Tray®/2000. A structural questionnaire was used to associate the positive results with selected socio-demographic variables. The raw data was organized and analysed by the use of SPSS version 24 software. Results: A prevalence of 2.6% intestinal parasite was found among the study population with hookworm and Enterobius vermicularis having detection rate of 0.6% and 2.0% respectively. However there were no Ascaris lumbricoides and Trichuris trichiura detected in the study population. A prevalence of 13.4% of the samples was positive for E. coli and 4.7% were identified as pathogenic E. coli strains: Enteroaggregative Escherichia coli (EAEC), Atypical Enteropathogenic Escherichia coli (APEC), Typical Enteropathogenic Escherichia Coli (TPEC) and Enterotoxigenic Escherichia coli (ETEC) distributed with prevalence percentage of 2%, 0.3%, 1.1% and 0.3% respectively. The study also revealed a significant association between hand child hygiene with the prevalence of E. coli. Conclusion: Environmental sanitation conditions like type of toilets and lack of safe drinking water is closely associated with the prevalence of E. coli among the school going children. / NRF

Thesis advisor: Summer S. Hawkins / Thesis advisor: David Takeuchi / Adolescence is a critical developmental stage where the health behaviors and choices that adolescents make have the potential to affect their long-term health and well-being (Centers for Disease Control and Prevention, 2014). This dissertation contributes three distinct studies on the contextual influences that shape adolescents' health behaviors. The first study, "The Role of Psychosocial Conditions on Sexually Transmitted Infection (STI) Risk among U.S. Young Adults," grounded in life course and syndemics theory, utilized logistic regressions to examine the role of co-occurring psychosocial conditions (childhood sexual abuse and physical abuse; depression and illicit drug use in adolescence) on STI infection (chlamydia and trichomoniasis) and sexual risk behaviors among U.S. young adults. Multiple co-occurring psychosocial conditions had an additive effect on sexual risk behaviors but no effect was observed on STIs. The second study, "Sexually Transmitted Infections and Neighborhood Poverty: The Role of Individual Resilience and Social Connectedness," utilized resilience and ecological systems theory, and logistic regressions to test if individual resilience and social connectedness (maternal, peer, and school) moderate the association between concentrated neighborhood poverty and STIs (chlamydia and trichomoniasis) among U.S. young adults. The study's main finding is that youth who reported more school connectedness and lived in high concentrated poverty in adolescence were less likely to test positive for chlamydia but were more likely to test positive for trichomoniasis. Utilizing a similar framework, "Sleeping in a Digital World: The Role of Excessive Media Use on Sleep Inadequacy Among U.S. Adolescents," examined family and neighborhood determinants that shape adolescent sleep behaviors. Grounded in the ecological systems theory and social learning theory, logistic regressions, stratified by age (aged 10-12 vs. 13-17), were used to examine the associations between excessive media use and sleep inadequacy. The study found that among older adolescents, sleep inadequacy was associated with excessive computer use. Older adolescents who watched television excessively and had media present in the bedroom were more likely to be sleep inadequate. Together, these three studies shed light on the different contextual environments in which adolescents experience health risks and resilience and will help to inform interventions that promote adolescent health and well-being. / Thesis (PhD) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Social Work. / Discipline: Social Work.

Submitted in partial fullfillment of the requirements of a Masters degree in Clinical Psychology University of Zululand, 2003. / Research shows that prevention campaigns have been successful in raising awareness about AIDS and even in teaching people how to protect themselves, i.e. "Abstain, Be Faithful, Condomise" where they have failed dismally is in convincing people especially the youth of today as to how to apply it. The aim of the study was to investigate qualitatively the sexual practices of adolescents in relation to sexually transmitted diseases and acquired immuno-deficiency syndrome. The study investigated the determinants of condom using behaviour amongst school going adolescents, in the Durban and Verulam metropolitan region of Kwa-Zulu Natal. The motivation for the study was contexualised within the preventative health model which views the consistent and correct use of condoms as a primary strategy in preventing the spread of STD's and HIV/AIDS. In South Africa the health promotion campaigns focusing on safe sex practices and condom use have met with limited success as evidenced in this study. The sexual behaviour of adolescents is a key factor in influencing HIV transmission and sexually transmitted diseases. The reason for this behaviour is that most youths are inconsistent condom users and those who become sexually active at an early stage, run a greater risk to being exposed to HIV and STD's, both because of multiple partners and increased episodes of unprotected sex. The results indicate that on a very superficial level, South African adolescents possess good knowledge about transmission and prevention. The reason for this is that in order to produce behavioural changes, education programmes on sex and AIDS should include cognitive and behavioural skills training, addressing interpersonal problem solving, planning and assertive communication. Furthermore the under-resourced health sector, inaccessible health facilities, poor education and preventative measures do not empower the youth to make health choices responsibly It is envisaged that the recommendations from the research would ensure that existing health facilities are accessible to the youth today. Family planning clinics which are decentralised and offer a youth day programme in respect of sexuality education and proper use of contraceptives and condoms, ensuring full confidentiality. It is further hoped that this research would show that prevention and education messages are more effectively conveyed to the youth in South Africa, emphasising cognitive and behavioural skills training, with the co-operation and co-ordinated efforts of all departments and non governmental organisation, as well as by those infected themselves.

Trichomonas vagina/is is a common sexually transmitted disease, affecting women more often than men. It has only been seen to undergo mitosis, even though published studies have confinned the organism has meiotic proteins. These meiotic proteins are known to function in other organisms with a key protein in homologous recombination, DMCl. RT-PCR analysis shows low expression ofDMCl in mitotically-growing cultures, and we found that some stresses on the organism increase DMCl expression. Polyclonal antibodies raised against DMCl protein have been used to test whole celllysates of the Tl and G3 strains of Trichomonas vagina/is but no obvious expression has been detected. We also used western blot analysis to show that superoxide dismutase is expressed in the standard lab strains Tl and G3 and immunocytochemistry studies showed that HA-tagged SOD6 protein localizes in the cytoplasm. Lastly, we found that SOD protein abundance increased in the CDC085 strain compared to Tl and G3, especially under aerobic conditions.

Faculty of Health Sciences School of Family Medicine 0335022 asmartc@yahoo.co.uk / The epidemic of Sexually Transmitted Infections (STIs), including HIV infection, is one of the major challenges facing South Africa at the present time. Controlling the epidemic of conventional STIs will decrease the suffering and complications caused by these diseases as well as the spread of HIV/AIDS. In order to manage patients in an efficient and cost-effective way, the WHO has advocated syndromic management. This approach is characterised by the management of persons with STIs by providing treatment for a group of diseases, which may cause one or more signs or symptoms, rather than by treating a specific disease. The incidence of STIs is very high in South Africa and many patients with STIs are consulting private general practitioners but very little information is available on syndromic management in general practice. To this view, sexually transmitted diseases tally sheets were given to twenty self selected private general practitioners and were requested to complete sheets for all STI and non- STI patients for a period of eight weeks. Also a demographics questionnaire with regard to the doctors and their practices was given to the doctors for completion. The data was captured and analysed using the Microsoft Access and the EpiInfo 6 statistical package 5 The results indicated that although private general practitioners manage a fair number of STI patients, not all are familiar with syndromic management. While recognising that the respondents were self-selected, 19 (95%) of the 20 participating doctors were very keen to attend courses on syndromic management. It is recommended that more information be made available to general practitioners on syndromic management.

<p> This thesis deals with the problem of digital communication over noisy dispersive channels. The dispersion causes the overlapping of successive received pulses thus creating intersymbol interference which severely limits the performance of conventional receivers designed to combat only additive interference or noise.</p> <p> In this thesis Bayes estimation theory has been applied to obtain a new, optimum, unrealizable receiver structure for the improved reception of noisy, dispersed, pulse amplitude-modulated (PAM) signals. By making certain approximations, a realization of this structure, known as the estimate feedback receiver or equalizer, is obtained. It consists of the combination of a matched filter and a nonlinear, recursive equalizer having, in the case of binary signals, a hyperbolic tangent nonlinearity in the feedback path. The well known decision feedback equalizer is shown to be a small noise limiting case of the estimate feedback equalizer. A saturating limiter is also considered as an approximation to the hyperbolic tangent nonlinearity.</p> <p> A new adaptive algorithm for the iterative adjustment of the estimate feedback equalizer is derived. It incorporates an extrapolation process which has the purposes of accelerating convergence of the equalizer's parameters to their optimum values and of maintaining the equalizer's frame of reference. It is constrained so that the equalizers parameters always move toward their optimum values.</p> <p> Computer simulations are used to demonstrate the properties of the adaptive estimate feedback equalizer and to compare them to those of presently known equalizers. When the estimate feedback equalizer is used, without a matched filter preceding it, to equalize phase distorted channels, its performance is seen to be superior to that of existing equalizers. The performance of an equalizer using a saturating limiter in place of the optimum hyperbolic tangent nonlinearity is seen to be almost as good as that of the estimate feedback equalizer.</p> / Thesis / Doctor of Philosophy (PhD)

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