Dissertations / Theses on the topic 'HIV spread'
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1
Duncan, Christopher J. A. "Macrophage-CD4⁺ T cell interactions in HIV-1 spread." Thesis, University of Oxford, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669849.
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Macrophages and CD4+ T cells are the main targets for productive human immunodeficiency virus-1 (HIV-1) infection in vivo. HIV-1 transmission at immune cell synapses, such as the multi-molecular HIV-1-induced virological synapse (VS) formed between T cells, is a more efficient method of viral dissemination than infection by cell-free virus, with important implications for HIV-1 prophylaxis and eradication. Infected macrophages can transfer HIV-1 to CD4+ T cells in a contact- dependent manner. However, the mechanism(s) of intercellular HIV-1 transmission between primary macrophages and CD4+ T cells are poorly defined. Here I investigate the organisation of the macrophage-T cell VS, which like the VS formed between T cells is dependent on envelope glycoprotein (Env) binding to CD4, and is stabilised by ICAM-1/LFA-1 interactions. However, unlike the T cell VS, where polarised budding of virions occurs at the donor cell membrane, VS-transmission from macrophages involves actin-dependent relocation of HIV-1 contained within the macrophage virus-containing compartment. Macrophage VS-mediated transmission results in highly efficient productive T cell infection at multiplicities capable of largely overcoming antiretroviral inhibition. Compared with cell-free infection of T cells, VS-transmission by macrophages is equally susceptible to broadly neutralising antibodies (bNAbs) against gp120, but relatively resistant to bNAbs targeting the membrane-proximal external region of gp41, probably via steric hindrance. In a related project, I investigated how HIV-1-infected CD4+ T cells might infect macrophages. Interaction of macrophages with HIV-1-infected CD4+ T cells resulted in rapid phagocytic uptake of the infected T cells, which correlated with efficient productive macrophage infection. This route of transmission also permitted macrophage infection with transmitted/founder HIV-1 clones that inefficiently replicate in macrophages following cell-free inoculation, potentially implicating macrophages in the mucosal amplification of transmitted HIV-1. Overall, these data indicate an important role for cell-to-cell transmission between macrophages and CD4+ T cells in various aspects of HIV-1 pathogenesis.
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Eaton, Jeffrey. "The spread and control of HIV in southern Africa." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/11065.
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HIV has disproportionately affected southern Africa. This region, which comprises 2% of the worlds population, is home to an estimated 34% of all people living with HIV, 29% of new HIV infections globally in 2010, and 30% of AIDS-related deaths. A strengthened response to the epidemic by countries in southern Africa in recent years has brought life-prolonging antiretroviral therapy to the majority of those in need of treatment, and declines from peak levels of HIV incidence over the past decade are a reason for optimism. But, in 2010, 770,000 new HIV infections occurred. A better understanding of why the epidemic has spread so severely in this region is required to inform strategies to reduce and eventually eliminate new HIV infections. This thesis uses data analysis and mathematical modelling to understand the interaction between behavioural and biological factors that may have contributed to the spread of HIV in southern Africa, and the implications of these for controlling the epidemic. It focuses specifically on two topics of recent attention for public health decision makers in southern Africa: concurrent sexual partnerships and HIV treatment as prevention. Chapters explore the interaction between high HIV infectiousness during primary HIV infection and concurrent sexual partnerships, describe and evaluate a consensus indicator for concurrency, develop a method to adjust for high levels of missing data in sexual behaviour surveys and examine trends in sexual behaviours in a high HIV prevalence population in South Africa, create a mathematical model to examine the potential impact of antiretroviral therapy on HIV incidence in hyperendemic settings, and systematically compare the predictions of twelve different mathematical models of the impact of HIV treatment as prevention in South Africa. Taken together, through these topics we come to understand more broadly the complexity of the epidemiological context in which HIV spreads in southern Africa.
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Iwuagwu, Chinyere I. "Preventing the Spread of HIV Among Homeless Youth in California." Thesis, Capella University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10685916.
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The implications of nonadherence consistently show that nonadherence or poor adherence diminishes the efficacy of ART and have resulted in the increasing rate of hospitalization, mortality and morbidity among people living with HIV/AIDS despite advancement in medicine and science. The purpose of this study was to explore the phenomenon of adherence to HIV antiretroviral regimens among HIV-infected homeless youth in California. The goal of the study was to clearly understand the perception and perspectives of the issue of adherence from the standpoint of those closest to the individuals experiencing the phenomenon.
A renowned HIV/AIDS service organization in California was selected for the study, and the staff were interviewed. The findings from the study uncovered specific facilitators and barriers to adherence faced by homeless youth living with HIV/AIDS. The study established that one of the major differences between homeless youth and the general population was their attitude to HIV/AIDS; unfortunately, most of the homeless youth in California do not regard HIV as a serious health problem. The study also found that the most serious public health problems in the county where the research study was conducted were homelessness and substance abuse and as such some of the HIV infected youth sell their HIV medications to buy street drugs, while some who are lucky to be HIV-negative wished they were positive, so they could qualify for free housing and other free financial services.
The research study concluded that the quicker homelessness is addressed among youth living with HIV/AIDS the more realistic it will be to focus on medication adherence and ultimately focus on preventing the spread of HIV in California. The research study provides direction for future multifaceted study directed towards addressing the issues of homelessness, substance abuse and prevention of the spread of HIV/AIDS among homeless youth living with HIV/AIDS disease as they are all interconnected and one cannot be solved without the other.
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Hay, Gordon. "Modelling the spread of HIV/AIDS amongst injecting drug users." Thesis, University of Strathclyde, 1999. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21443.
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The sharing of injecting equipment by injecting drug users (IDUs) is one of the primary causes of the spread of HIV in Scotland. Mathematical models of disease spread can explore the transmission dynamics and can assist in evaluating control strategies such as needle exchanges. A simple deterministic model is examined and local and global stability results are presented. A deterministic model in which infected IDUs are considered separately from uninfected IDUs is created. The infectivity of a needle is then examined. It is first assumed that the infectivity of a needle depends on the amount of infectious material within it, then models in which this infectivity varies over time from injection are explored. Models in which the initial infectiousness of a needle depend on the length of time the person who infected it had been infected with HIV are also presented. A stochastic model is developed and explored in a threefold manner; analytically, numerically and using Monte-Carlo simulation methods. In particular, the probability that the disease dies out is examined. Although these simple models use only a small number of parameters, little is known about the values that these parameters may take. Seroprevalence and behavioural data from Glasgow are used to inform these models, and also to provide an estimate for the probability than an IDU becomes infected after injecting with an infected needle. The effect that the variability in the parameter values may have on the spread of the disease is examined by performing both an uncertainty analysis and a sensitivity analysis. These show that the two behavioural parameters that can be altered by control strategies have a greater influence on the spread of the disease than some other parameters.
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Lutambi, Angelina Mageni. "Basic properties of models for the spread of HIV/AIDS." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/19641.
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Thesis (MSc)--University of Stellenbosch, 2007.ENGLISH ABSTRACT: While research and population surveys in HIV/AIDS are well established in developed countries, Sub-Saharan Africa is still experiencing scarce HIV/AIDS information. Hence it depends on results obtained from models. Due to this dependence, it is important to understand the strengths and limitations of these models very well. In this study, a simple mathematical model is formulated and then extended to incorporate various features such as stages of HIV development, time delay in AIDS death occurrence, and risk groups. The analysis is neither purely mathematical nor does it concentrate on data but it is rather an exploratory approach, in which both mathematical methods and numerical simulations are used. It was found that the presence of stages leads to higher prevalence levels in a short term with an implication that the primary stage is the driver of the disease. Furthermore, it was found that time delay changed the mortality curves considerably, but it had less effect on the proportion of infectives. It was also shown that the characteristic behaviour of curves valid for most epidemics, namely that there is an initial increase, then a peak, and then a decrease occurs as a function of time, is possible in HIV only if low risk groups are present. It is concluded that reasonable or quality predictions from mathematical models are expected to require the inclusion of stages, risk groups, time delay, and other related properties with reasonable parameter values.
AFRIKAANSE OPSOMMING: Terwyl navorsing en bevolkingsopnames oor MIV/VIGS in ontwikkelde lande goed gevestig is, is daar in Afrika suid van die Sahara slegs beperkte inligting oor MIV/VIGS beskikbaar. Derhalwe moet daar van modelle gebruik gemaak word. Dit is weens hierdie feit noodsaaklik om die moontlikhede en beperkings van modelle goed te verstaan. In hierdie werk word ´n eenvoudige model voorgelˆe en dit word dan uitgebrei deur insluiting van aspekte soos stadiums van MIV outwikkeling, tydvertraging by VIGS-sterftes en risikogroepe in bevolkings. Die analise is beklemtoon nie die wiskundage vorme nie en ook nie die data nie. Dit is eerder ´n verkennende studie waarin beide wiskundige metodes en numeriese simula˙sie behandel word. Daar is bevind dat insluiting van stadiums op korttermyn tot ho¨er voorkoms vlakke aanleiding gee. Die gevolgtrekking is dat die primˆere stadium die siekte dryf. Verder is gevind dat die insluiting van tydvestraging wel die kurwe van sterfbegevalle sterk be¨ınvloed, maar dit het min invloed op die verhouding van aangestekte persone. Daar word getoon dat die kenmerkende gedrag van die meeste epidemi¨e, naamlik `n aanvanklike styging, `n piek en dan `n afname, in die geval van VIGS slegs voorkom as die bevolking dele bevat met lae risiko. Die algehele gevolgtrekking word gemaak dat vir goeie vooruitskattings met sinvolle parameters, op grond van wiskundige modelle, die insluiting van stadiums, risikogroepe en vertragings benodig word.
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Do, Thao. "Imaging of HIV-1 spread from T cells and macrophages to astrocytes." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:07ffd971-0b25-4990-8d17-001d943ebfa5.
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CD4+ T cells and macrophages are the principal targets of HIV-1. They can be productively infected with the virus and transfer virions to contacting bystander cells. It has been suggested that soon after initial infection, free virions and virus-bearing or infected T cells and macrophages can enter the brain, triggering a cascade of inflammatory signals and recruitment of other immune cells. Chronic inflammation and increased viral antigens in the brain lead to HIV-1 associated neuropathy. Once free virions or infected cells enter the central nervous system, the first type of brain cells that they are likely to encounter are astrocytes, which extend endfeet around the blood vessels. These cells have been observed to contain virions and viral products, but their permissivity to productive infection has not been clearly demonstrated. By contrast, productive infection of resident microglia and perivascular macrophages is well established. Here, I investigate the permissivity of astrocytes to HIV-1 infection and found no evidence of infection by the free route. However, I found that astrocytes intimately contact HIV-1 infected macrophages and CD4+ T cells and, in some cases, extend filopodial membrane toward the infected cell. In astrocyte-T cell contact sites, termed synapses, virions appear to move along the astrocytic filopodia from the T cell to the astrocyte. In this case, the target cell mediated viral transfer across the intercellular gap. HIV-1-infected macrophages released virus that associated with astrocytes, remaining either on the surface of the astrocytes or within intracellular compartments. HIV-1 bound to astrocytes could be transmitted efficiently to permissive cells in trans. However, astrocyte-associated virus was sensitive to inhibitors including proteases and neutralizing antibodies, suggesting a surface-accessible compartment. This work provides insight into mechanisms of HIV-1 spread in the brain from infected CD4+ T cells and macrophages to astrocytes and their potential as virus reservoirs. I also optimized high resolution, correlative focused ion beam scanning electron microscopy technology to answer fundamental biological questions. I demonstrate the application of the technology to study skeletal muscle cell differentiation mechanisms. I combine the power of genetic mapping with structural analysis to qualitatively and quantitatively describe cellular states and functions. Using semi-automatic image processing analysis, I was able to compute high volumes of data and generate statistics that relate quantitative measurements of cellular structures to functions. The toolset developed here will be instrumental in studying cells and tissues in both research and clinical applications.
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Ngubane, Siegfried Johan. "Gender roles in the African culture : implications for the spread of HIV/AIDS." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4195.
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Thesis (MPhil (Industrial Psychology. Africa Centre for HIV/AIDS Management))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: The AIDS epidemic presently engulfing South Africa is mostly based on heterosexual transmission. This paper discusses the male role in African culture in the HIV and AIDS context. Issues facing African women, domestic violence in particular, remain a pervasive problem. Women have not yet reached a level of equality and are still being dominated by their male partners. Women’s subordination can be directly linked to the increasing number of women becoming infected with HIV/AIDS, especially within the African cultural context. Culture plays a vital role in determining the level of health of the individual, the family and the community. This is particularly relevant in the context of Africa, where the values of extended family and community significantly influence the behaviour of the individual. The behaviour of the individual in relation to family and community is one major cultural factor that has implications for sexual behaviour and HIV/AIDS prevention and control efforts. As the impact of HIV/AIDS in South Africa remains unabated, a culture-centred approach to prevention, care and support is increasingly desirable as a critical strategy. The focus of prevention of the heterosexual AIDS epidemic has been on women. The role of men in sexual decision-making has not been emphasized enough in AIDS prevention approaches. As a result, the heterosexual epidemic for women continues unabated because of the lack of attention to the behaviour of male sex partners. Discussion focuses on the cultural and contemporary sexual culture as shaping factors in the enactment of high-risk sexual behaviour. There are numerous social, political, cultural and economic factors affecting the HIV pandemic in the SA region. The main ones are: low status of women and male dominance in sexual and economic relations; sexual abuse (of particularly young girls); historic and current separation of families resulting from the migrant labour system which resulted in multiple sexual partners; high use of sex workers due to single-sex quarters at the workplace; cultural resistance to the use of condoms; high rates of other STD’s; and high levels of poverty and other inequalities such as health access and education. Stigma about HIV is also a barrier to reaching the most vulnerable, including those already infected. The paper draws the conclusion that discrimination against women, coupled with male dominance in all aspects of social structures; polygamous marriages were prescribed and supervised by maledominated social structures has increased the prevalence rate of HIV/AIDS in the African cultural context.
AFRIKAANSE OPSOMMING: Die HIV/Vigs pandemie wat tans Suid Afrika oorweldig is meestal die gevolg van heteroseksuele oordrag. Hierdie verhandeling bespreek die manlike rol in die Afrika kultuur in die konteks van MIV en Vigs. Aspekte wat die Afrika vroue in die gesig staar in terme van gesinsgeweld bly `n aanhoudende probleem. Vroue word steeds deur hul manlike maats gedomineer word en dus steeds nie `n vlak van gelykheid bereik het nie. Die onderdrukking van vroue kan direk gekoppel word aan die toenemende aantal vroue wat met MIV/Vigs geïnfekteer word – veral in die Afrika konteks. Kultuur speel ʼn kritieke rol in die bepaling van die gesondheidsvlak van die individu, gesin en gemeenskap. Dit is besonder relevant in die Afrika konteks, waar die waardes van `n uitgebreide gesin en gemeenskap ʼn enorme invloed het op die optrede van `n individu. Hierdie optrede in verhouding tot die gesin en gemeenskap is `n geweldige factor wat implikasies het op seksuele gedrag en op pogings tot voorkoming en beheer van MIV/Vigs. Terwyl die impak van MIV/Vigs in Suid Afrika ongesteurd voortstu, word `n kultuur gesentreerde benadering tot voorkoming, versorging en ondersteuning toenemend nodig as `n kritieke strategie. Die fokus op die voorkoming van die heteroseksuele Vigs pandemie was tot nou toe op vroue. Die rol van mans in seksuele besluitneming was tot dusvêr nie voldoende beklemtoon in Vigs voorkomende benaderings nie. Die gevolg is dat die heteroseksuele Vigs pandemie vir vroue ongesteurd voortduur weens die gebrek aan aandag op die gedrag van manlike seksmaats. Bespreking fokus op die kulturele en kontemporêre seksuele kultuur as vormende faktore in die uitvoer van hoë risiko seksuele gedrag. Daar is verskeie sosiale, politieke, kulturele en ekonomiese faktore wat die MIV/Vigs pandemie in die streek beïnvloed. Die belangrikstes is: lae status van vroue; manlike dominasie in seksuele en ekonomiese verhoudings; seksuele mishandeling – veral van jong meisies; historiese en huidige skeiding van gesinne voortspruitend uit die stelsel van trekarbeid – wat aanleiding gegee het tot `n verskeidenheid van seksuele maats; die hoë voorkoms van sekswerkers agv enkelgeslag woonkwartiere by die werksplek; kulturele weerstand teen die gebruik van kondome; hoë voorkoms van seksueel oordraagbare siektes; hoë vlakke van armoede en ander ongelykhede soos toegang tot gesondheidsdienste en onderwys. Die stigma van MIV/Vigs is ook `n hindernis in die bereiking van die mees kwesbare, insluitend die wat geïnfekteer is. Hierdie verhandeling maak die gevolgtrekking dat diskriminasie teen vroue, gekoppel met manlike dominasie in alle aspekte van sosiale strukture; poligamiese huwelike wat voorgeskryf word en onder toesig is van manlik gedomineerde sosiale strukture, die voorkoms van MIV/Vigs in die Afrika kulturele konteks verhoog het.
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Symeonides, Menelaos. "HIV-1-Induced Cell-Cell Fusion: Host Regulation And Consequences For Viral Spread." ScholarWorks @ UVM, 2016. https://scholarworks.uvm.edu/graddis/589.
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Human immunodeficiency virus type 1 (HIV-1) is a human retrovirus of the lentivirus subgroup which primarily infects T cells and macrophages, and causes acquired immune deficiency syndrome (AIDS). Since its emergence in the early 1980s, HIV-1 has caused a global pandemic which is still responsible for over one million deaths per year, primarily in sub-Saharan Africa.
HIV-1 has been the subject of intense study for over three decades, which has resulted not only in major advances in cell biology, but also in numerous drug treatments that effectively control the infection. However, cessation of treatment always results in reemergence of the infection due to the ability of HIV-1 (and other lentiviruses) to establish a persistent quiescent infection known as latency. The elimination of latently-infected cells is the primary goal of current research towards a cure for HIV-1, alongside efforts to develop vaccines, which have thus far been fruitless.
The spread of HIV-1 to susceptible target cells (which express the receptor CD4 and a co-receptor; CXCR4 or CCR5) can take place when antigen-presenting cells, such as dendritic cells, capture virus particles and then pass them on to target cells, without themselves becoming infected. Alternatively, productively infected T cells or macrophages can spread HIV-1 either by shedding virus particles to the milieu, which are then stochastically acquired by target cells, or through transient contacts between infected and uninfected cells known as virological synapses (VSs). VS-mediated cell-to-cell transmission is thought to be highly efficient due to the release of virus directly onto (or very near to) a target cell, and some evidence suggests that the VS is a privileged site which allows the virus to evade neutralizing antibodies and drugs. However, and most importantly, it is of central interest to us because the same transient cell adhesions that facilitate virus transfer can also result in the fusion of the two cells to form a syncytium, due to the presence of the viral fusogen Env and its receptor and co-receptor on either side of the VS. While T cell syncytia can be found in vivo, they remain small, and it appears that the majority of VSs resolve without fusion.
The regulation of HIV-1-induced cell-cell fusion and the fate of those syncytia are the focus of the work presented here. A family of host transmembrane proteins, the tetraspanins, which regulate cell-cell fusion in other contexts (e.g. the fusion of myoblasts to form and maintain myotubes), were found to inhibit HIV-1-induced cell-cell fusion. Our investigations have further characterized this regulation, concluding that tetraspanins allow cells to reach the fusion intermediate known as hemifusion before their ability to repress fusion takes effect. In parallel, because syncytia are nevertheless found both in infected individuals and in a humanized mouse model for HIV-1, we also became interested in whether small T cell-based syncytia were able to participate in HIV-1 spread by transmitting virus to target cells. Using a simple three dimensional in vitro culture system which closely recapitulates those in situ observations, we found that small syncytia can contact target cells and transmit virus without fusing with them. Overall, these studies further our understanding of HIV-1-induced syncytia and reveal a previously unrecognized role for these entities as active participants in HIV-1 spread.
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Culshaw, Rebecca Veronica. "Mathematical models of cell-to-cell and cell-free viral spread of HIV infection." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24826.pdf.
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Cuadros, Diego Fernando. "THE ROLE OF CO-INFECTION IN THE SPREAD OF HIV IN SUB-SAHARAN AFRICA." UKnowledge, 2011. http://uknowledge.uky.edu/biology_etds/1.
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The cause of the high HIV prevalence in sub-Saharan Africa is incompletely understood, with heterosexual penile-vaginal transmission proposed as the main mechanism. Heterosexual HIV transmission has a very low probability; further, a single estimation of heterosexual probability of HIV transmission fails to reproduce the variation associated with important biological cofactors. In particular, studies of HIV incidence suggest that co-infection with other infectious diseases influence the HIV transmission, and therefore might substantially vary the pattern of the spread of the infection. To assess the effect of co-infection on the spread of HIV, I developed and analyzed several mathematical and statistical models based on published data. The results show that despite the low probability of heterosexual transmission per sexual contact, the inclusion of individual variation generated by transient but repeated increases in HIV viral load associated with co-infections may provide a biological basis for the accelerated spread of HIV in sub-Saharan Africa, and raises the possibility that that the natural history of HIV in sub-Saharan Africa cannot be fully understood if individual variation in infectiousness is neglected.
Co-infection might be a key explanatory variable for the rapid spread of HIV infection in sub-Saharan Africa; in fact, co-infection may be a necessary factor, rather than merely being a contributing factor, in the successful spread and survival of HIV in populations where heterosexual vaginal-penile contact is the main mechanism of transmission. Consequently, broad population based control strategies to decrease infectivity and reduce the incidence of other sexual and parasitic infectious diseases might be effective strategies in diminishing the spread of HIV in sub-Saharan Africa.
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Namazzi, Elizabeth B. "Ugandan students' perspectives on the spread and prevention of hiv/aids : cultural practices and education." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54250.
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My study investigated perspectives that underlie Ugandan high school students’ understandings of the spread and prevention of HIV/AIDS and how they influenced by cultural practices. I adopted an interpretive case study approach that employed mixed methods, guided by the sociocultural and practice theoretical frameworks. Data were collected on students from seven select schools in central Uganda over 12 weeks. The students participated in the study by completing an adopted HIV/AIDS knowledge questionnaire with a transformed scale from True/Fase to Likert before and after experiencing HIV/AIDS lesson instructions. The questionnaire served as a stimulus to evocation of the students’ perspectives. These perspectives were extracted from the questionnaire data using Principal Component Analysis. Results revealed five key perspectives: Perceptual and behavioural risks associated with proximity to HIV/AIDS victims; Hygienic practices; Behavioural/practice causes and transmission of HIV/AIDS; Predictive, preventive and transmissive knowledge of HIV/AIDS; and Naïve notions of prevention and treatment of HIV/AIDS. These perspectives were further interrogated through qualitative methods including classroom observation and focus group interview/discussions. After HIV/AIDS-focused lessons, a similar analysis on the after lesson questionnaire data also revealed that underlay students’ understandings of the spread and prevention of HIV/AIDS. Three of the pre-lesson perspectives persisted while two (Hygienic practices and Behavioural/practice causes and transmission of HIV/AIDS) collapsed, with two new ones (Taboo-like prescriptions of knowledge of infection) emerging in the after lesson experience analysis. Also a realization emerged among the students of the greater risk of HIV/AIDS infection if they subverted the cultural norms. It became noteworthy that the students communicated their understandings metaphorically, which often conveyed unscientific understandings about the spread and prevention of HIV/AIDS. The study’s findings have critical implications for policy and the way curricula and instruction are interpreted and enacted in the classroom.Education, Faculty of
Curriculum and Pedagogy (EDCP), Department of
Graduate
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Titanji, B. K. "Exploring the impact of antiretroviral drugs on the cell-to-cell spread of HIV-1." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1457394/.
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Recent observations on the reduced susceptibility of HIV-1 cell-to-cell infection to inhibition by Reverse Transcriptase Inhibitors (RTIs) have raised questions on the bearing this mode of spread may have on the successful treatment of HIV-1, the maintenance of viral reservoirs and viral pathogenesis. This thesis presents a detailed assessment of the individual drug classes, which constitute first-line and second-line antiretroviral therapy, with regard to their ability to inhibit HIV-1 cell-to-cell infection in comparison to cell-free infection. Special emphases is given to the study of Protease Inhibitors (PIs), which have a mechanism of action different from RTIs, present a higher barrier to the selection of drug-resistant viruses, are highly potent and very important in both first-line and second-line treatment of HIV-1 infection. Also, PIs have not been studied before in the context of cell-to-cell spread of HIV-1. The results obtained show that different classes of antiretroviral drugs have different potencies against cell-to-cell spread of HIV-1. While PIs are equally effective at inhibiting cell-to-cell and cell-free spread of HIV-1, RTIs especially those of the Nucleoside Reverse Transcriptase Inhibitor (NRTI) class are ineffective inhibitors of cell-to-cell spread of the virus. This thesis also assesses the impact of combination antiretroviral therapy on these two modes of viral infection, using drug synergy analysis by the median effect principle. We show that combination antiretroviral therapy is effective against both cell-to-cell and cell-free HIV-1 infection. However in the context of antiretroviral drug resistance, cell-to-cell spread may contribute to a reduced efficiency of combination antiretroviral therapy in blocking the spread of infection. Overall, the study provides a better understanding of the impact of antiretroviral therapy on cell-to-cell spread of HIV-1 and within reason, bearing in mind the limitations of in vitro models, gives some insight on the possible clinical implications of these observations for current HIV-1 therapy.
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Rama, Parbavati. "Placing the dead :the spatial distribution and spread of HIV in a major South African city." Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
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The aim of this study was to establish a new understanding of the epidemiology of HIV/AIDS at the municipal level, but at the same time upholding the anonymity of the HIV infected and AIDS sufferers. Innovative research techniques such as the use of GIS (geographic information systems) as a research tool contributed to disclosing the patterns of the HIV pandemic in the Nelson Mandela Metropole that were not obvious or visible before. GIS involved geographic maps that detect the spatial relationship between HIV prevalence rates and vectors that drive the pandemic.
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Taljaard, Dirk J. "Tracking the risk factors and impact of an intervention to reduce the spread of the HIV." Doctoral thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/3848.
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Midiwo, Aoko. "An analysis of the debate over the control of the spread of HIV infection and AIDS." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 1988. http://digitalcommons.auctr.edu/dissertations/3447.
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Mulongeni, Pancho. "Epidemiologic synergy - the contribution of heterosexual HIV transmission to the spread of HIV among men who have sex with men (MSM) in South Africa." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/23711.
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Background: Could heterosexual HIV transmission be a driver of HIV infections that occur in men who have sex with men (MSM)? Noting the disproportionately high HIV prevalence among MSM across a variety of settings, this subpopulation is often considered as sources of new infections, overlooking the possibility of HIV transmission from the heterosexual – general – population to MSM. Objective: To assess the relative contribution of heterosexual transmission of HIV for onwards transmission of HIV from one man to another. Method: An agent based model of heterosexual transmission of HIV in South Africa was extended to simulate the HIV epidemic among MSM from 1990 to 2012. The model included gay men (who only have sex with men), bisexual men (who have partners of both sexes) in addition to men who have sex with women. HIV prevalence and sexual behaviour data collected among MSM in South Africa served as calibration data. Results: The model estimated that 28.7% (IQR: 27.4-28.9%) of MSM were HIV positive in 2010. By simulating a counterfactual HIV epidemic in South Africa, where HIV only spreads via male-male sex, we observe a decline in HIV incidence occurring in MSM by 56% over the period of 1990-2010, relative to the historical reality of HIV spreading via heterosexual and male-male sex. Analogously, HIV prevalence among MSM in 2010 under the counterfactual scenario reached only 10.0% (IQR 2.8- 17.4%), substantially less than HIV prevalence estimates from samples of MSM in South Africa. Conclusion: Roughly half of the HIV infections among MSM in South Africa can be attributed to the high levels of HIV prevalence in the general population. Scale up of interventions to target high risk behaviours with male partners should dispel possible misconceptions of bisexually active or heterosexual MSM as lower risk partners, relative to those MSM in gay communities.
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Mulenga, Kennedy Chola. "Changing risky behaviour through worldview transformation : a pastoral intervention to the spread of HIV/AIDS in Zambia." Thesis, University of Pretoria, 2010. http://hdl.handle.net/2263/24798.
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The study investigates how the church in Zambia can effectively facilitate change toward reducing HIV-risky behaviour. The researcher posits that an intricate connection exists between HIV-risky behaviour and the socio-cultural context of majority people groups in Zambia. He further argues that much risky behaviour is imbedded in pervasive socio-cultural norms and traditions propelled by a worldview which essentially resists transformation. From an insider’s perspective the researcher will design a praxis model for transforming Zambian worldview facets with regard to HIV/AIDS predisposing behaviours in order to achieve enduring HIV risk reduction. The study reviews current literature on HIV behavioural change theories and models to understand where the theories have taken all the stakeholders, including theological praxis. The study will demonstrate the link between Zambian cultural worldviews and trends in sexual behaviour which, arguably, facilitates the proliferation of HIV risky behaviour. The study culminates in designing an evangelical theological praxis/model for transforming relevant cultural worldviews toward changing HIV risky behaviour in Zambia.Thesis (PhD)--University of Pretoria, 2010.
Practical Theology
unrestricted
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Kibui, Christine. "Exploring Culturally Specific Practices that Might Exacerbate the Spread of HIV/AIDS in the Luhya Community of Western Kenya." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/iph_theses/109.
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ABSTRACT CHRISTINE KIBUI Exploring Culturally Specific Practices that Might Exacerbate the Spread of HIV/AIDS in the Luhya Community of Western Kenya. (Under the direction of Frances McCarty, Faculty Member and Donna Smith, Research Associate) INTRODUCTION: In the year 2007, there were 22 million people aged 15 and above living with HIV, 1.9 million new HIV infections, and 1.5 million HIV related deaths in sub-Saharan Africa. In the same year, the rest of the world had an estimated 11 million people aged 15 and above living with HIV, 0.8 million new HIV infections and 0.5 million deaths related to HIV. OBJECTIVE: The purpose of this study is to explore the culturally perceived practices that may have the capacity to exacerbate the spread of HIV/AIDS among the members of the Luhya community in Western Kenya. METHODOLOGY: The Interpretive Phenomenological Analysis approach and the Health Belief Model served to inform the study. Qualitative analysis was conducted on focus group discussions and individual interviews conducted in Kanduyi, Webuye, Bungoma, Bukembe, and Misikhu towns of Bungoma districts, Western Kenya province. RESULTS: Circumcision, polygamy, concurrent relationships, funeral services and wife inheritance are some of the cultural practices that may put the members of the Luhya community at risk for HIV transmission. Poverty, low health literacy, unsafe sexual practices exacerbate HIV risk among the communities. DISCUSSION: The issue of culture cannot be overlooked when it comes to HIV prevention interventions in Bungoma district. It will be necessary for Public health workers to work with all stakeholders in the community to identify interventions that are acceptable to the community.
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Dowling, Karilynn, Taylor Riedley, MacKenzie Broome, and Nicholas E. Hagemeier. "Stopping the Spread by Using Sterile Needles Instead: A Rural Community Pharmacy Hepatitis C/HIV Prevention Feasibility Study." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etsu-works/5432.
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Purpose: Prescription and illicit opioid abuse have disproportionately impacted the Central Appalachian Region. Centers for Disease Control and Prevention (CDC) data indicate the region is home to many of the 220 counties most vulnerable to rapid dissemination of Hepatitis C Virus (HCV) and HIV related to injection drug use. Growing evidence supports the role of community pharmacies in HCV/HIV prevention by providing access to non-prescription sterile syringes; however, research has largely been confined to major metropolitan areas. The objective of this study is to evaluate the feasibility of community pharmacies in Central Appalachia serving as access points for sterile syringes. Methods: This study was approved by the Institutional Review Board. Using state directories of health professionals, community pharmacists from Northeast Tennessee, Western North Carolina, and Southwest Virginia were randomly selected to participate in key informant interviews to inform understanding of the impact of attitudes, beliefs, and state-level policies on pharmacists’ syringe dispensing behaviors (N=15). Informed consent was obtained prior to initiating the interviews and participants were provided modest compensation for their time. The semi-structured interviews were guided by Theory of Planned Behavior constructs to focus the interview on evidence-based predictors of behaviors. Interviews were audio-recorded, de-identified, transcribed, and are currently being thematically analyzed by the research team with NVivo software. The results of this study are expected to inform development of a survey instrument for a larger quantitative evaluation of pharmacists' perceptions on syringe dispensing in the region. Results: Not applicableConclusion: Not applicable
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Mills, Stephen Jay. "A passage to India : male migration and the spread of HIV and other sexually transmitted infections in rural Nepal." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415674.
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Tsafack, Temah Chrystelle. "The Role of Income and Gender Inequalities in the Spread of the HIV/AIDS Epidemic : Evidence from Sub-saharan Africa." Clermont-Ferrand 1, 2008. https://tel.archives-ouvertes.fr/tel-00281162/document.
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Bien que le VIH soit devenu une cause majeure de pauvreté et de décès sur le continent africain, la relation entre pauvreté et épidémie du VIH/Sida n’est pas aussi simple qu’elle ne le paraît. En effet, si à l’échelle mondiale les pays les plus touchés sont les pays pauvres, au niveau de l’Afrique Sub-saharienne, les pays les plus affectés sont les plus riches. Ces pays se trouvent également être ceux qui affichent les distributions de revenu les plus inégalitaires. Un autre fait saillant de la distribution de l’épidémie du VIH/Sida en Afrique Sub-saharienne est qu’elle est la région du monde avec la plus grande proportion des femmes infectées. Cette thèse s’intéresse à l’estimation de l’impact des inégalités de revenu et de genre dans la propagation de l’épidémie du VIH/Sida dans les pays d’Afrique au sud du Sahara. A l’aide d’un modèle de panel de données macroéconomiques de 42 pays d’Afrique Sub-saharienne sur la période 1997-2005, nous examinons le lien entre les inégalités de revenu et de genre d’une part et l’évolution de l’épidémie du VIH/Sida d’autre part en tenant compte des autres déterminants traditionnels de l’épidémie. Nos résultats montrent que l’inégalité de revenu favorise la diffusion de l’épidémie du VIH/Sida. Son impact est un impact spécifique qui ne transite pas par la pauvreté ; de plus la relation entre ces deux variables est significative et robuste à des spécifications alternatives du modèle et à une analyse dynamique. Quant à l’inégalité de genre, cette variable, appréhendée par trois indicateurs, joue un rôle important dans l’évolution de l’épidémie du VIH/Sida en Afrique Sub-saharienne. Plus précisément, il apparaît que c’est l’inégalité de genre en matière de revenu et de participation à l’activité économique qui favorise la propagation de l’épidémie au sein de la population jeune (15-24 ans), tandis que la variable de genre déterminante pour l’épidémie au sein de la population adulte dans son ensemble (15-49 ans) est l’inégalité de genre en matière d’éducationThroughout African continent, HIV/AIDS epidemic has became a major cause of death and poverty. Nonetheless, the relation between poverty and HIV/AIDS epidemic is not as straightforward as it might first appear. Indeed, if at the international level the most affected regions are the poorest, in Sub-Saharan Africa however, the most affected countries also happen to be the richest. Meanwhile, these countries are also those with the least egalitarian income distributions in the world. Moreover, the distribution of the epidemic across both sexes differs according to regions, with Sub-Saharan Africa being the most gender-affected region: more than half of infected people there are women. Our focus in this dissertation is to assess the importance of income and gender inequalities as determinants of the spread of HIV/AIDS pandemic in Sub-Saharan Africa. Using a panel data of 42 African countries from the period 1997-2005, we examine the link between income and gender inequalities on the one hand and HIV/AIDS epidemic on the other hand by introducing these variables among the traditional determinants of the epidemic. Our results suggest that there is indeed a link between income inequality and HIV/AIDS epidemic. Moreover, the correlation remains even after we control for poverty and when we perform a dynamic analysis of the epidemic. Furthermore, women’s education and economic independence appear to be critical determinants of the pandemic. Specifically, our results indicate that the component of gender inequality which drives the epidemic among young population (15-24) is gender inequality in income and participation to economic life, while it is gender inequality in education which fuels the epidemic among adult population
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Dupont, Maeva. "Identification of novel factors involved in the exacerbation of HIV-1 infection and spread among macrophages in the tuberculosis context." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30211.
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Mycobacterium tuberculosis (Mtb), la bactérie responsable de la tuberculose (TB), et le virus de l'immunodéficience humaine (VIH-1), l'agent du syndrome de l'immunodéficience acquise (SIDA), accélèrent leurs progressions mutuelles chez les patients co-infectés. Alors que de nombreuses données cliniques rapportent une augmentation de la charge virale dans les sites anatomiques co-infectés, les mécanismes qui en sont responsables restent insuffisamment décrits. Mtb cible principalement les macrophages. Nous émettons l'hypothèse que l'infection des macrophages par Mtb créé un microenvironnement propice à la réplication du VIH-1 au niveau des sites co-infectés. Pour le montrer, j'ai utilisé un modèle in vitro précédemment établi par mes équipes (le cmMTB - pour " conditioned media of Mtb-infected macrophages "). Celui-ci permet de mimer un environnement tuberculeux, par la différenciation et l'activation des macrophages vers un profil " M(cmMTB) ", largement retrouvé dans les poumons lors d'une tuberculose active. En rejoignant le laboratoire, j'ai participé à l'étude des mécanismes responsables de l'augmentation de la réplication virale dans le contexte de co-infection, en utilisant ce modèle. Nous avons trouvé que les M(cmMTB) forment de nombreux nanotubes (ponts intercellulaires), leur permettant de transférer plus de virus d'un macrophage à l'autre, et conduit à une forte augmentation de la production virale. L'objectif principal de ma thèse a donc été d'identifier, dans un contexte tuberculeux, de nouveaux facteurs impliqués dans l'augmentation de la réplication du VIH-1 dans les macrophages. Pour cela, une analyse transcriptomique des M(cmMTB) a été réalisée, révélant deux facteurs essentiels : le récepteur Siglec-1 et les interférons de type I (IFN-I) via STAT1. Dans un premier temps, j'ai étudié le rôle de Siglec-1 dans la synergie entre Mtb et le VIH-1 dans les macrophages. D'abord, j'ai montré que son expression de surface était augmentée par le cmMTB, de façon dépendante des IFN-I. Ensuite, j'ai établi que l'abondance des macrophages alvéolaires exprimant Siglec-1 chez les primates non-humains co-infectés avec Mtb et le virus de l'immunodéficience simienne corrélait avec la sévérité de la pathologie, et était associée à la signalisation des IFN-I, via l'activation de STAT1. De plus, j'ai identifié une nouvelle localisation de Siglec-1 le long d'un sous-type de nanotubes.[...]Mycobacterium tuberculosis (Mtb), the bacteria causing tuberculosis (TB), and the human immunodeficiency virus type 1 (HIV-1), the etiological agent of acquired immunodeficiency syndrome (AIDS), act in synergy to exacerbate the progression of each other in co-infected patients. While clinical evidence reveals a frequent increase of the viral load at co-infected anatomical sites, the mechanisms explaining how Mtb favours HIV-1 progression remain insufficiently understood. Macrophages are the main target for Mtb. Their infection by the bacilli likely shapes the microenvironment that favours HIV-1 infection and replication at sites of co-infection. To address this issue, I took advantage of an in vitro model mimicking the TB-associated microenvironment (cmMTB, "conditioned media of Mtb-infected macrophages") previously established in the laboratory; a model that renders macrophages susceptible to intracellular pathogens like Mtb. Upon joining the team, I participated in the study on how Mtb exacerbates HIV-1 replication in macrophages, using this model. We found that cmMTB-treated macrophages (M(cmMTB)) have an enhanced ability to form intercellular membrane bridges called tunneling nanotubes (TNT), which increase the capacity of the virus to transfer from one macrophage to another, leading to the exacerbation of HIV-1 production and spread. The principal objective of my PhD thesis was to identify novel factors that are involved in the exacerbation of HIV-1 replication in macrophages in the context of tuberculosis. To this end, a transcriptomic analysis of M(cmMTB) was conducted, and revealed two key factors: the Siglec-1 receptor and type I interferon (IFN-I)/STAT1 signaling. The first part of my PhD thesis dealt with the characterization of Siglec-1 as a novel factor involved in the synergy between Mtb and HIV-1 in macrophages. First, I demonstrated that its increased expression in M(cmMTB) was dependent on IFN-I. Second, in Mtb and simian immunodeficiency virus co-infected non-human primates, I established a positive correlation between the abundance of Siglec-1+ alveolar macrophages and the pathology, associated with the activation of the IFN-I/STAT-1 pathway. [...]
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Timiun, Godwin Aondohemba. "Contextual factors influencing unsafe sexual behaviours and the spread of HIV/AIDS Amongst the Tiv People of North Central Nigeria." Thesis, Australian Catholic University, 2017. https://acuresearchbank.acu.edu.au/download/989c32153d76f182db7007deb1fff2c84f1ef3a5cbe578b793c7d40cd9311986/3943844/Timiun_2017_Contextual_factors_influencing_unsafe_sexual_behaviours.pdf.
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Background Unsafe sex is the second most important risk factor for disability and deaths in the poorest countries and the ninth most important in developed countries. It is one of the major sources of HIV infection, the global leading infectious killer of human beings. Globally, in 2013, there were 2.1 million new infections, 35 million adults living with HIV/AIDS, and more than 39 million people have died of HIV/AIDS related causes since the first case was identified in 1981. Currently, about 24.7 million and 3.2 million individuals are living with HIV in Africa and Nigeria respectively. Despite the fact that penetrative sex involves partners, previous research had concentrated on the individual to provide evidence of unsafe sexual behaviours and its correlates and these assumptions have been used for biomedical and behavioural change interventions at the individual level to curb the spread of HIV/AIDS; though with some degree of success, the aim to curb the spread of HIV/AIDS had fallen short of the targets due to the impact of relational and distal factors which have not previously been adequately addressed.
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Boullé, Mikaël [Verfasser]. "HIV cell-to-cell spread results in earlier onset of viral gene expression by multiple infections per cell / Mikaël Boullé." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1148426051/34.
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Keene, Thomas. "Stopping The Spread of AIDS among Women in Sub-Saharan Africa, What Works and What does not: A Comparative Study of Uganda and Botswana." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/33768.
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Using feminist theory and comparative analysis, this thesis will investigate why women in sub-Saharan Africa are more vulnerable to HIV/AIDS than men. Among non-governmental organizations and inter-governmental organizations, HIV/AIDS has always been a gender issue because it is clear that women are more vulnerable to the disease, socially, culturally and biologically. Through two case studies -- one on Uganda where the HIV prevalence rate has dropped considerably in recent years, and one on Botswana, where the HIV prevalence rate has drastically increased in recent years â I will shed light on womenâ s vulnerability to HIV, how this vulnerability can be counteracted, and how these counteractive efforts are implemented by women and state governments (if they are implemented at all). It is hypothesized that the empowerment of women may stifle the spread of HIV.Master of Arts
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Freeman, Esther. "The role of herpes simplex virus Type 2 in the spread and control of HIV in four Sub-Saharan African Cities." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429308.
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Mnguni, Grace. "An assessment of the effect of HIV/AIDS policy in combating the spread of the disease within Buffalo City Metropolitan Municipality:Eastern Cape." Thesis, University of Fort Hare, 2016. http://hdl.handle.net/10353/2956.
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Due to its rapid spreading, AIDS has been declared a global epidemic. Especially sub-Saharan Africa has been the most affected by the epidemic. South Africa is no exception to the devastating impact of the epidemic. Over the past few years, HIV-prevention initiatives have been underway on a full scale in an effort to combat the destructive powers of the epidemic in the country. These initiatives appear to have adopted a health-belief approach in their strategies to decrease HIV-infections. This approach to HIV-prevention assumes that the desired behavior change, namely increasing safe sexual practices and decreasing high-risk HIV/AIDS behavior, can be achieved through rational decision-making based on knowledge of the disease and its consequences. The findings of the studies on sexual behavior and HIV/AIDS such as KAPB (knowledge, attitudes, practice and beliefs) studies appear to reaffirm the fact that knowledge alone is neither sufficient nor effective in bringing about the appropriate behavior change to combat HIV/AIDS. These studies point towards a high level of knowledge about AIDS in the general population, yet the ever increasing infection rate remains undeterred. The ANC came to power in 1994 after 10 years of National Party inaction with regard to AIDS. The National AIDS plan, endorsed by incoming minister Dr Nkosazana Dlamini-Zuma, was insufficiently informed by the institutional and social realities of South Africa. Like other policy blueprints of this period, it over-estimated the economic, and especially human, resources at the disposal of incoming government. Moreover, this avowedly multi-sect oral HIV/AIDS plan, designated a “presidential lead project”, was situated in a national department of health in the throes of transformation. Because health is in part a provincial prerogative, AIDS was vulnerable to further administrative obstruction in a second tier of bureaucracy from the previous regime. Competing claims on resources in the poorer provinces, the demands of administrative reconfiguration, and very uneven provincial capacity, further undermined implementations.
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Davidsson, Frida, and Victoria Zakrison. "Knowledge and apprehensions concerning HIV/AIDS of Indonesian adolescents : Reflections upon the possibility for professional nurses to spread knowledge to prevent suffering." Thesis, Högskolan i Borås, Institutionen för Vårdvetenskap, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19197.
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HIV/AIDS is a global and expanding problem, not least in Indonesia, which is the country with the fastest growing epidemic in Asia. In rural areas of Indonesia it is usually harder to get information compared to urban areas. The lack of information and the fact that it is often taboo to speak about the subject result in common experiences of discrimination and shame for people living with HIV/AIDS. The aim of the study is to describe the knowledge of HIV and AIDS among Indonesian youths living in rural compared to urban areas. Furthermore to get knowledge about their experiences concerning the disease and also how they get information about the subject. A questionnaire was handed out for 15 to 16 years old students at two different high schools. One was located in the rural and the other in the urban area and altogether there were 40 respondents included in the study. The result showed that the knowledge was higher among the students from the urban school although the average knowledge for both schools was quite similar compared to earlier studies. Internet was considered to be the source giving most information about HIV/AIDS and guidance (from an expert in the subject) was suggested as the best source. The respondents stated that the disease is connected to isolation and discrimination, in addition the importance of giving support to the infected. Since guidance was stated to be the best source of information, the nurse has an important role as an expert. The nurse is obliged to promote health and prevent illness and by spreading information this can be done. It will also act to prevent suffering, both physically and psychologically, since HIV/AIDS is such a destructive and stigmatizing disease.Program: Sjuksköterskeutbildning
Uppsatsnivå: C
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Dzama, Hedrix A. "Is the Use of the Rubber as a Preventive Measure to the Spread of HIV/AIDS Morally Justifiable? Ethical Reflections on the Controversy." Thesis, Linköping University, Centre for Applied Ethics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2110.
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Since the Human Immunodeficiency Virus (HIV) that causes Acquired Immune Deficiency Syndrome (AIDS) was discovered in the 1980s, the condom has scientifically proven to be the only technological device that can prevent transmission of the virus during sexual intercourse. This technical approach to the HIV has strongly emphasized that prevention is only possible if the condom is properly used. However, as a technological artifact the condom has shown that its use is laden with values. The question of values on condoms has brought in a heated debate on the moral justifications of its use. In Malawi, just as in other African countries, the Faith Community has rejected the Governmentsplea to promote condoms as the preventive measure against the virus.The Faith Community has emphasized on abstinence and mutual faithfulness as the only reliable means to the prevention of HIV/AIDS. The main argument from the Faith Community is that condoms promote promiscuity. Nevertheless, the Government agrees with the Faith Community on abstinence and mutual faithfulness, but still insists on condom use as a preventive measure against the virus. The Government argues that the condom is the only proven technical approach to the HIV prevention and therefore it should be promoted. T
he main purpose of this study is to attempt an ethical analysis of the arguments for and againstcondom use as the preventive measure against HIV. In this case, the study tries to analyse the Government and Faith Community stands on condoms. In relation to the arguments for and againstcondom use, the study also touches such areas as: the concept of rights and condom use, ethics of condom advertisement, African cultural values versus condom use and the implications of condom use on behaviour change. From the study, it has been argued that condoms should be promoted. The argument comes from that understanding that AIDS has plundered Africa than any war or disease in human history, and therefore, it needs to be stopped. In this case, such theories as, Utility, Love, Autonomy, Rights and umunthu moral conscience have been used to support the argument.
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Rosales, Gerpe María Carla. "The Role of APOBEC3 in Controlling Retroviral Spread and Zoonoses." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31484.
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APOBEC3 (A3) proteins are a family of host-encoded cytidine deaminases that protect against retroviruses and other viral intruders. Retroviruses, unlike other viruses, are able to integrate their genomic proviral DNA within hours of entering host cells. A3 proteins hinder retroviral infectivity by editing retroviral replication intermediates, as well as by inhibiting retroviral replication and integration through deamination-independent methods. These proteins thus constitute the first line of immune defense against endogenous and exogenous retroviral pathogens. The overall goal of my Master's project was to better understand the critical role A3 proteins play in restricting inter- and intra-host transmission of retroviruses. There are two specific aspects that I focused on: first, investigating the role of mouse APOBEC3 (mA3) in limiting the zoonotic transmission of murine leukemia retroviruses (MLVs) in a rural environment; second, to identify the molecular features in MLVs that confer susceptibility or resistance to deamination by mA3. For the first part of my project, we collected blood samples from dairy and production cattle from four different geographical locations across Canada. We then designed a novel PCR screening strategy targeting conserved genetic regions in MLVs and Mouse Mammary Tumor Virus (MMTV) and MMTV-like betaretroviruses. Our results indicate that 4% of animals were positive for MLV and 2% were positive for MMTV. Despite crossing the species barrier by gaining entry into bovine cells, our study also demonstrates that the bovine A3 protein is able to potently inhibit the spread of these murine retroviruses in vitro. The next question we asked was whether mA3 could also mutate and restrict murine endogenous retroviruses and thereby partake in limiting zoonotic transmission. Moloney MLV and AKV MLV are two highly homologous murine gammaretroviruses with opposite sensitivities to restriction by mA3: MoMLV is resistant to restriction and deamination while AKV is sensitive to both. Design of MoMLV/AKV hybrid viruses enabled us to map the region of mA3 resistance to the region encoding the glyco-Gag accessory protein. Site-directed mutagenesis then allowed us to correlate the number of N-linked glycosylation sites with the level of resistance to deamination by mA3. Our results suggest that Gag glycosylation is a possible viral defence mechanism that arose to counteract the evolutionary pressure imposed by mA3. Overall, my projects show the important role A3 proteins play in intrinsic immunity, whether defending the host from foreign retroviral invaders or endogenous retroviral foes.
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Ngamije, James. "The effect of the growth in global tourism development in Cape Town on health promotion with specific reference to the spread of HIV/AIDS." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/792.
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Thesis presented in fulfilment of the requirements for the degree:
Master of Technology Environmental Health
Department of Environmental and Occupational Studies
Faculty of Applied Sciences at the Cape Peninsula University of Technology
Cape Peninsula University of Technology
2014International Tourism development has been given a positive image as a tool to pro-mote development in the world of the poor, and an important tool for response in achieving the Millennium Development Goals (MDGs) by 2015 placing health at the heart of poverty alleviation. International tourism development is not only a sector that fit the applicability of international development theory but is also often voiced and enthusiastically supported. As an economic development industry, international tourism development has been a choice for many of the poorest countries in the world as it is supported by international institutions such as the United Nations and World Bank to address the notions of inequalities and poverty reduction alongside environmental considerations. In addition, tourism is perceived to pull wealth from rich countries into the world of the poor with a high potential to trickle down to the vil-lages and the poorest communities. However, the evidence that international tourism development can benefit the poor on grassroots level is difficult to prove because no data in this regard is available. Given the fact that the time stipulated to complete the noble goals of MDGs is very near, this study intends to ask: to what extent is health and sustainable tourism development applicable in Africa? And a number of ques-tions arise that this thesis, in a broad sense seeks to address. What are barriers to the contribution of the international tourism development in less developed countries (LDCs)? To which context of international development theories, is international tour-ism development positioned with relationship to economic growth, equitable distribu-tion of profits, and sustainable development and health? And who are ultimately the beneficiaries of international tourism development? For the most part, the contribu-tion of this research project deals critically with tourism opportunities and risks related to community health. The focus is on tourism development and inequality, poverty alleviation alongside environmental consideration, reducing gender inequality and exploitation, HIV/AIDS and promoting sustainable tourism development and health, to mention few. This research project aims to presents an important contribution to the debate regarding the relationship between international tourism development in the world of the poor such as Africa in the age of global political economy or free trade, and the high prevalence of HIV/AIDS. This research investigates current international development approaches that offer new and exciting insights. However, there is a need for further critical analysis of the complex dynamics on the effects of interna-tional tourism development throughout the sequence of international development iii theories in developing countries, particularly in Sub-Saharan Africa. It seems that in the absence of a moral responsibility and collaboration of all stakeholders in promot-ing equity in tourism benefits, opportunities offered for sustainable tourism develop-ment and health will not materialize. The policy maker in tourism planning in develop-ing countries who are now asked to be more responsible to a broader set of econom-ic and social needs in developing countries are concerned about planning for desira-ble economic benefits as well as social and cultural impacts. Tackling issues from ethnological perspectives, advocators for sustainable tourism development in the world of the poor such as United Nations World Tourism Organisation (UNWTO) and World Bank advocate socially responsible and sustainable tourism development and health in accordance to the decided upon MGDs. From analysis of the opportunities and risks related to integrating international tourism development as a panacea led the researcher interest in testing how small state grapple with the dilemma of tourism development and community health. This study combined two approaches, namely the (i) human security threats and (ii) the use of Clive Thomas’ four prong typology as well as using Cape Town as a case study to meet this objective.
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Johansson, Matilda. "Social Marketing : A way to reach and empower vulnerable people through prevention work against the spread of HIV/AIDS and Sexually Transmitted Infections in Ethiopia." Thesis, Ersta Sköndal högskola, Institutionen för socialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:esh:diva-1783.
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Millions of people in the world are infected by HIV/AIDS or/and other Sexually Transmitted Infections, STIs. Ethiopia is, with its population on almost 94 million people, one of the worst affected countries. One of the methods that are used in the prevention work in order to combat the spread of HIV/AIDS and STIs in Ethiopia is Social Marketing, a concept that adopts traditional marketing techniques in order to obtain social change. This inductive study explores how three various Ethiopian organizations are utilizing Social Marketing in their HIV/AIDS and STI prevention work throughout Ethiopia, how the concept can be used to achieve attitudinal- and behavioral change by people, as well as if the organization’s various Social Marketing projects strive to provide vulnerable groups of the Ethiopian society with empowerment, and if so, in what ways. The empirical material was collected through six qualitative interviews and two focus group discussions during an eight-week long stay in Ethiopia during March-May, 2012. The findings of this study have been analyzed through theories about human behavior with a focus on behavior change, as well as various definitions and concepts of empowerment. The study’s result shows that Social Marketing can be utilized in several ways in the HIV/AIDS and STI prevention work in Ethiopia to obtain attitudinal- and behavior changes, for instance by using various commercial techniques, street campaigns, information/education/behavioral change materials, as well as trainings, outreach work and peer education, which aims to educate people about HIV/AIDS, STIs, condoms and condom use. The organization’s joint Social Marketing project “Wise Up-program” includes Drop In Centers and Cooperative Activity for sex workers. The findings of this essay shows that these projects do strive to provide vulnerable groups of the Ethiopian society with empowerment, psychologically as well as economically.
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Kuhl, Björn. "Interrelationship between tetherin-mediated restriction and its Vpu-mediated antagonism in HIV-1 cell-to-cell spread and the potential to develop Vpu as an antiviral target." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104781.
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This doctoral thesis comprises three parts. The first two parts (Chapter 2 and 3) define the role of the host cell restriction factor tetherin in restriction of HIV-1 cell-to-cell spread. These chapters also characterize the tetherin-inducible cell line Sup-T1 that was used in Chapter 4 to investigate whether the antiviral activity of protease inhibitors might partially be attributed to tetherin modulation. Tetherin is an intrinsic host cell restriction factor that inhibits virus release by linking the viral membrane of the budding virus to the cellular membrane. The antiviral activity of tetherin has been commonly attributed to its cell surface expression. In HIV-1 infections, the viral protein Vpu antagonizes the tetherin-mediated restriction of virus release and downmodulates tetherin from the cell surface. In Chapter 2, we show that tetherin, besides restricting virus release, also restricts direct viral cell-to-cell spread. We also provide evidence that Vpu poses a fitness cost to HIV-1 in regard to cell-to-cell spread in the absence of tetherin, but is necessary for efficient cell-to-cell spread in the presence of tetherin. Tetherin appears also to play a role in synapse formation. In Chapter 3, we characterized cell line specific differences of the tetherin-Vpu interrelation in regard to cell surface expression of tetherin and virus release. However, Vpu-mediated tetherin antagonism in regard to cell-to-cell spread was similar in all cell lines and seemed to be independent of the level of tetherin cell surface downmodulation. In Chapter 4 we assessed whether protease inhibitors, whose antiviral activity partially depends on modulation of transmembrane proteins, may also modulate tetherin cell surface expression and/or the Vpu-mediated downmodulation of cell surface tetherin. As such, modulation was not apparent; thus, the antiviral activity of PIs is unlikely to be influenced by tetherin modulation activity.Cette thèse de doctorat se compose de trois parties. Les deux premières parties (Chapitres 2 et 3) s'intéressent au rôle du facteur de restriction cellulaire tetherin dans l'inhibition de la propagation du VIH-1 de cellule à cellule. Ces Chapitres décrivent également la caractérisation de la lignée cellulaire Sup-T1 qui exprime la tetherin de manière inductible. Cette lignée cellulaire est utilisée dans le Chapitre 4 pour étudier si l'activité antivirale des inhibiteurs de protéases peut, en partie, être due à la régulation de la tetherin. La tetherin est un facteur de restriction intrinsèque de l'hôte qui inhibe le relargage du virus en liant la membrane virale du virion bourgeonnant à la membrane cellulaire. L'activité antivirale de la tetherin est généralement attribuée à son expression à la surface cellulaire. Dans l'infection par le VIH-1, la protéine virale Vpu empêche l'action de la tetherin et limite son expression à la surface de la cellule hôte. Dans le Chapitre 2, nous montrons qu'en plus d'inhiber le relargage des virions, la tetherin inhibe également la propagation de cellule à cellule. Nos résultats suggèrent que Vpu réduit la capacité infectieuse du virus en l'absence de la tetherin mais est absolument nécessaire à la propagation de cellule à cellule en présence de tetherin. La tetherin semble jouer un rôle dans la formation de synapse intercellulaire. Dans le Chapitre 3, nous analysons des différences entre des lignées cellulaires dans l'interaction fonctionnelle entre Vpu et la tetherin. Ces différences contribuent à la régulation de l'expression de la tetherin à la surface cellulaire et au relargage des virions dans ces différentes lignées cellulaires. Néanmoins, aucune différence dans la régulation de la propagation de cellule à cellule n'a pu être observée. À ce titre, l'inhibition de la propagation de cellule à cellule semble indépendante du niveau d'expression de la tetherin à la surface cellulaire. Dans le Chapitre 4, nous étudions si les inhibiteurs de protéase, dont l'activité antivirale dépend en partie de la régulation de protéines transmembranaires, peuvent également moduler l'expression de la tetherin à la surface cellulaire et/ou l'inhibition de la tetherin par Vpu. Cette étude suggère que l'activité antivirale des inhibiteurs de protéases ne dépend pas d'un effet sur la tetherin.
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Perzynski, Adam Thomas. "Between Facts and Voices: Medical and Lay Knowledge of the Spread of Hepatitis C." online version, 2008. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=case1207328082.
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Robinson, Maureen Louise. "Johannes Hispalensis and the manuscript tradition : the history surrounding the time of John of Seville and the spread of his work." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326885.
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Silva, Francilene Amaral da. "Avaliação tecnológica e atividade antioxidante de produtos secos por spray-drying de ilex paraguariensis A. St. Hil.-aquifoliaceae (erva-mate)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/12620.
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Avaliação tecnológica e atividade antioxidante de produtos secos por spray-drying de Ilex paraguariensis A. St. Hil. – Aquifoliaceae (erva-mate) Ilex paraguariensis A. St. Hil. é uma espécie popularmente conhecida como erva-mate. O presente trabalho refere-se ao desenvolvimento e caracterização tecnológica de produtos secos por spray-drying, a partir de solução extrativa aquosa de I. paraguariensis, bem como de frações polifenólicas. Adicionalmente foi desenvolvido e validado um método de cromatografia líquida de alta eficiência (CLAE) para a quantificação de polifenóis presentes tanto na matéria-prima vegetal como nos produtos secos. O método mostrou-se adequado para a quantificação de polifenóis em todas as preparações de I. paraguariensis. Quatro produtos secos por spray-drying foram preparados a partir do decocto. Entre os quatro produtos, o produto contendo 30 % de Aerosil® (PSI-A) apresentou as melhores características tecnológicas e de estabilidade frente à fotodegradação. Na avaliação da atividade antioxidante, no modelo experimental in vitro, tanto os produtos secos como as frações polifenólicas demonstraram atividade antioxidante, de maneira dose-dependente, caracterizada pela redução da quimiluminescência no ensaio de TRAP, baixos níveis de TBARS e aumento da atividade scavenger de radicais hidroxila. Fatias de fígado de ratos foram utilizadas como modelo ex vivo. Entre os produtos por spray-drying testados PSI-A e PSI-D e a fração FAB foram eficazes na redução da produção de TBARS quando comparados ao controle pré-incubado com ter-butilhidroperóxido (t- BHT), corroborando os ensaios in vitro. Para o ensaio in vivo empregou-se o modelo de dano hepático induzido por tetracloreto de carbono (CCl4), sendo o produto seco PSI-A selecionado para avaliação com base nos resultados obtidos na caracterização tecnológica. A administração de PSI-A, por via oral, durante 30 dias, na dose de 386 mg/kg, resultou em dano hepático menor, evidenciado por níveis menores de lipoperoxidação e maior atividade das enzimas superóxido desmutase e catalase, quando comparados ao controle. O conjunto de resultados sugere que o desenvolvimento tecnológico dos produtos secos, bem como de frações purificadas apresentou atividade antioxidante significante medida em ensaios in vitro e ex-vivo. Adicionalmente, os resultados também evidenciam efeito hepatoprotetor frente ao estresse oxidativo e dano hepático provocado pelo tetracloreto de carbono, medidos em ensaios in vivo. Estudos adicionais visando a investigar o papel destes produtos em patologias em que o estresse oxidativo parece estar envolvido são necessários.Ilex paraguariensis A. St. Hil. is a plant specie traditionally known as maté. The present work was designed in view to develop, in semi-industrial scale, spray-dried extracts of Ilex paraguariensis from aqueous extracts as well as polyphenol fractions. Four spray-dried extracts were prepared from the aqueous extract using different excipients. In order to quantify the polyphenols present in raw plant material, spray-dried extracts and polyphenol fractions, a liquid chromatography (LC) method was validated. The spray-dried extract containing 30% of Aerosil® (SPD-A) presented the best technological characteristics and photostability. In vitro antioxidant activity evaluation of both spray-dried extracts and polyphenolic fractions showed a dose-dependent antioxidant activity. Quimiluminescence reduction in TRAP assay, low TBARS content and hydroxyl free radicals scavenger activity were observed. Rats liver slices were used for antioxidant test in ex vivo model.SPD-A and SPD-D (containing 15% of Aerosil® and 15% of Avicel®) spray-dried extracts and polyphenol fraction FAB were able to reduce TBARS production when compared to the control group preincubated with ter-butylhydroperoxide (t- BHT). Based on the technological characteristics and photostability, PSI-A spray-dried extract was selected for in vivo antioxidant activity evaluation using carbon tetrachloride (CCl4) induced hepatic damage as a model. Oral administration of 386 mg/kg of SPD-A during 30 days resulted in decreased liver damage as a consequence of lower lipoperoxidation levels and higher activity of superoxide dismutase and catalase enzymes when compared to a control group. In synthesis, the results suggest that both spray-dried extracts and purified fractions presented significant in vitro and ex vivo antioxidant activity. Additionally, in vivo antioxidant activity evaluation demonstrated a hepatic protection effect against oxidative stress and carbon tetrachlorideinduced damage. Further experiments aiming to investigate both spray-dried extracts and polyphenol fractions function in diseases involving oxidative stress represent a very interesting perspective.
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Weissmueller, Nikolas T. "Needle-free vaccination : formulation and dermal delivery of diphtheria toxin CRM197 mutant." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:be74f39b-1f36-451c-8200-4f14b701bcee.
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The unsafe use of needles propagates cross infections with bloodborne pathogens and reduces the positive impact of vaccinations on global health. While a plethora of needle-free injection devices exist, the reformulation of protein-based vaccines is largely empirical and costly, which presents a barrier to their widespread clinical application. This thesis contributes to the identification of approaches that facilitate rapid vaccine reformulation and enhance the immunogenicity of needle-free dry-powder vaccines with the help of novel antigen delivery platforms. We hypothesised that the thermodynamic stabilisation of diphtheria toxin mutant 197 (CRM197), a glycoconjugate vaccine carrier protein, may enhance its structural preservation during spray-freeze-drying (SFD), and that its formulation in either soluble, surface-adsorbed, or nanoparticle form impacts the elicited immune response. Differential scanning fluorimetry was used to study the effect of excipients on the thermal stability of CRM197. Dry-powder formulation of CRM197 used i) encapsulation into a thermodynamically stabilising excipient matrix by SFD, ii) surface-immobilisation via physisorption onto a novel potassium-doped hydroxyapatite (kHA) carrier microparticle formed by molten salt synthesis, and iii) chemical conjugation and surface presentation on amphiphilic block copolymer nanoparticles that were incorporated into SFD-powders (SFD-NP). The structural integrity of CRM197 was assessed by size separation in addition to various spectral and thermal analysis methods. The immunogenicity of dry-powder CRM197 formulations was subsequently tested in vivo. The results suggest that the thermodynamic stability of CRM197 in solution does not ensure its structural stability during SFD. While needle-free dermal vaccination with kHA-adsorbed CRM197 induced comparable antibody titres to conventional IM injection of alum-adjuvanted CRM197, needle-free SFD and SFD-NP powders were less immunogenic. The highest mean IgG titre and most balanced Th1/Th2 response was achieved with nanoparticle-conjugated CRM197 by IM, which outperformed the current clinical standard. Therefore, future vaccine design should combine thermodynamic and kinetic stability screening, and place special emphasis on the delivery and structural presentation of the antigen to the immune system.
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Murakami, Aureanna Nairne Negrão. "Efeito da nanofiltração e da microencapsulação por spray drying na estabilidade dos compostos bioativos do extrato aquoso de Ilex paraguariensis A. St. Hil." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/172356.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Ciência dos Alimentos, Florianópolis, 2016.Made available in DSpace on 2017-01-17T03:16:30Z (GMT). No. of bitstreams: 1 343254.pdf: 2998449 bytes, checksum: cc8dba8ce05fa45905b1d3809dc81f58 (MD5) Previous issue date: 2016
No extrato aquoso das folhas de erva-mate (Ilex paraguariensis A. St.Hil.) é encontrada uma grande variedade de compostos químicos comdiversas atividades biológicas, com destaque para os compostosfenólicos, com reconhecida atividade antioxidante. Na primeira etapadeste estudo, a nanofiltração (NF) foi aplicada para concentrar oscompostos bioativos do extrato aquoso de folhas de erva-mate. Oimpacto da NF na atividade antioxidante dos extratos foi avaliadoatravés de análises in vitro pelo método DPPH e com célulaseucarióticas de Saccharomyces cerevisiae. Verificou-se que os teores decompostos fenólicos totais e de ácido clorogênico, de metilxantinas,taninos condensados, clorofila e saponinas, e a atividade antioxidante invitro foram significativamente maiores no extrato concentrado quandocomparado ao extrato inicial. Na segunda etapa, o extrato concentradode erva-mate foi microencapsulado com maltodextrina com diferentesvalores de dextrose equivalente (DE) por spray drying. O efeito dosdiferentes DE de maltodextrina (10,2 (M10), 15,2 (M15) e 18,6 (M20))foi avaliado em função do teor de compostos fenólicos totais, atividadeantioxidante, rendimento dos compostos fenólicos microencapsulados,morfologia e tamanho de partícula, teor de umidade, atividade de água,dissolução, higroscopicidade, análise de cor e propriedades térmicas. Aretenção dos compostos fenólicos, após a microencapsulação por spraydrying e a estabilidade das microcápsulas a 5 °C, 25 °C e 45 °C, durante90 dias, também, foram verificados. As microcápsulas produzidas commaltodextrina com menor valor de DE (M10) apresentaram o maiorrendimento de encapsulação, além de melhores resultados paradissolução, higroscopicidade, teor de umidade e propriedades térmicas.Além disso, estas microcápsulas apresentaram melhor estabilidade emrelação aos compostos fenólicos e atividade antioxidante durantearmazenamento nas três temperaturas avaliadas.
Abstract : A wide variety of chemical compounds with different biologicalactivities, especially phenolic compounds, is usually found in aqueousextract of yerba mate leaves (Ilex paraguariensis A. St. Hil.) and it isvery important in science due this antioxidant activity. In the first stepof this study, a nanofiltration technique (NF) was used to concentratethe bioactive compounds of the aqueous extract of yerba mate leaves.The impact of the NF in the antioxidant activity of the obtained extractswas evaluated using in vitro analysis such as DPPH and Saccharomycescerevisiae eukaryotic cells. It was observed that the total phenoliccompounds and chlorogenic acid, methylxanthines, tannins, chlorophyll,saponins, and the in vitro antioxidant activity was significantly higher inthe concentrated extract when compared to the original extract. In thesecond step, the concentrated extract was microencapsulated usingmaltodextrin with different dextrose equivalent values (DE) applyingspray drying process. The effect of different maltodextrin DE (10.2(M10), 15.2 (M15) and 18.6 (M20)) was evaluated according to thecontent of phenolic compounds, antioxidant activity, yield ofmicroencapsulated phenolics, morphology and particle size, moisturecontent, water activity, dissolution, hygroscopicity, color analysis andthermal properties. The retention of phenolic compounds afterproduction of microcapsules and stability studies at 5 ° C, 25 ° C and 45° C for 90 days, were also investigated. The microcapsules producedwith maltodextrin DE (M10) showed higher yield of encapsulation, andbetter results for dissolving, hygroscopicity, and moisture content andthermal properties. In addition, these microcapsules showed morestability when compared to the phenolics and antioxidant activity duringdifferent storage temperatures.
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Fernandes, Beatriz Luci. "Tecnica de nanorisco para analise de adesão de revestimento de HA, depositada atraves de aspersão por plasma, sobre liga de titanio." [s.n.], 1999. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263416.
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Orientador: Cecilia A. C. ZavagliaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-07-25T02:10:22Z (GMT). No. of bitstreams: 1 Fernandes_BeatrizLuci_D.pdf: 8612737 bytes, checksum: 5b82e95884b98b376d5146b5ea2586e9 (MD5) Previous issue date: 1999
Resumo: Apesar dos 30 anos de história, engenheiros e pesquisadores continuam procurando soluções para problemas que persistem até os dias de hoje, em relação à resistência ao desgaste de superfícies articuladas e à fixação aos tecidos ósseos de implantes ortopédicos de quadril. Esses problemas estão interligados, desde que a formação de grandes partículas nas articulações é o principal fator responsável pela perda da prótese e a qualidade da fixação do implante determina a produção dessas partículas. O material das amostras, analisadas neste trabalho, foi um dos empregados atualmente em próteses totais de quadril não cimentadas, ou seja, liga Ti6Al-7Nb revestida de hidroxiapatita (HA), aplicada através da técnica de aspersão por plasma. O principal objetivo deste trabalho foi apresentar uma alternativa para a avaliação da resistência da interface, utilizando-se uma nova técnica, rápida e confiável. As informações contidas estão relacionadas à técnica de deposição de materiais em forma de pó através de aspersão por plasma; ao estudo da resistência à adesão da HA sobre a liga de titânio através de ensaio de nanorisco e à caracterização superficial das amostras por determinação da rugosidade superficial, difração de raio-X e imagens do Microscópio Eletrônico de Varredura
Abstract: In spite of 30 years of history, engineers and researchers in general, are still trying to find solutions for the problems related to wear resistance of sliding surfaces and related to biological attachment of hip prostheses. These two questions are connected since the debris released in the joints are the main factor for loosing the prostheses and the fixation quality determines the production of those debris. The samples analyzed on this work were made of materials presently applied on hip prostheses like Ti-6Al-7Nb alloy with hydroxyapatite coating applied by plasma spray method. The main purpose of this work was to present an alternative to analyze the adhesion strength between the HA and the Ti-6Al-7Nb alloy using a new technique, fast and reliable. The information presented are related to the plasma spray' s deposition technique using powdered materials, to the evaluation of the interface between the two materials through the nanoscratch test and to the surface characterization using a mechanical profiler (profilometer), an X-Ray Diffract meter and a Scanning Electron Microscope
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica
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Yatsu, Francini Kiyono Jorge. "Desenvolvimento tecnológico de grânulos esferoidais a partir de extrato seco de folhas e ramos de ilex paraguariensis St. Hil. aquifoliaceae (erva-mate)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/142758.
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O presente trabalho teve como objetivos produzir um extrato seco de Ilex paraguariensis por spray-drying, em escala semi-industrial, e desenvolver grânulos esferoidais a partir do extrato seco, pelo método de extrusão/esferonização, bem como caracterizar as propriedades físicas, químicas e tecnológicas e investigar a estabilidade dos principais constituintes polifenólicos de ambos produtos frente à radiação UVC e ao calor. O extrato seco apresentou partículas esféricas (tamanho médio de 19,6 μm), com superfície lisa, boas propriedades de fluxo e rendimento satisfatório (67 %). No teste de fotoestabilidade, o extrato seco se manteve estável frente à radiação UVC, por 48 h, nos diferentes materiais de acondicionamento (frascos de vidro âmbar, frascos de vidro transparente ou vidros de relógio). No teste de estabilidade acelerada (40 ºC, 75 % de umidade relativa, 4 meses), o extrato seco demonstrou ser higroscópico e sensível ao calor, especialmente quando acondicionado em frascos de polietileno, por serem permeáveis à umidade. Os grânulos esferoidais, por sua vez, apresentaram tamanho médio de 1,10 mm, forma e rendimento (78,7 %) satisfatórios, boa dissolução em água (89,44 a 100,05 %) e adequada recuperação (> 95 %) do conteúdo de polifenóis totais em relação ao extrato seco. Os grânulos esferoidais foram estáveis frente à radiação UVC quando acondicionados em frascos de vidro âmbar, entretanto, o teor de polifenóis totais foi reduzido quando as amostras foram acondicionadas em vidro de relógio ou em frascos de vidro transparente. No teste de estabilidade acelerada, os grânulos esferoidais demonstraram ser higroscópicos e sensíveis ao calor. Este efeito foi mais pronunciado quando as amostras foram acondicionadas em frascos permeáveis (de polietileno) do que em frascos impermeáveis (de vidro transparente). Os resultados apontam para a importância da redução da umidade residual tanto do extrato seco quanto dos grânulos esferoidais, bem como para a necessidade de acondicioná-los em embalagens com proteção contra a umidade e a luz, sob baixas temperaturas.The present work was designed to produce a dry extract of Ilex paraguariensis by the spray-drying process, in semi-industrial scale, and to develop pellets from dry extract, by the extrusion/spheronization method, as well as to characterize the physical, chemical and technological properties and to investigate the stability of the main polyphenol constituents from both products against UVC radiation and heat. The dry extract presented spherical particles (mean size of 19.6 μm), with smooth surface, good flow properties and satisfactory yield (67 %). In the photo stability test, the dry extract remained stable against UVC radiation, for 48 h, in all packaging material (amber glass bottles, transparent glass bottles or open-dishes). In the accelerated stability testing (40 ºC, 75 % relative humidity, 4 months), the dry extract demonstrated to be hygroscopic and sensible to the heat, especially when conditioned in polyethylene ethyl bottles because they are permeable to the humidity. The pellets presented mean size of 1.10 mm, satisfactory shape and yield (78.7 %), good dissolution in water (89.44 to 100.05 %) and good recovery (> 95 %) of the total polyphenol content in comparison with dry extract, the pellets were stable against UVC radiation when conditioned in amber glass bottles, however, the total polyphenol content was reduced when the samples were conditioned in open-dishes or in transparent glass bottles. In the accelerated stability testing, the pellets demonstrated to be hygroscopic and sensible to the heat. This effect was more pronounced when the samples were conditioned in permeable flasks (polyethylene ethyl bottles) than in semi-permeable flasks (transparent glass bottles). These findings point to the relevance of reducing the residual moisture of both dry extract and pellets, as well as to the necessity of conditioning both into opaque humidity tight packing, at low temperatures.
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Soderi, S. (Simone). "Evaluation of industrial wireless communications systems’ security." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526212463.
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Abstract The worldwide success of wireless communications was originally fueled by the possibility to replace existing cables with wireless solutions. This phenomenon imposed the development of security engineering as a multidisciplinary field. Although wireless solutions can reduce installation costs and allow introducing new services, the end–users expect it to have the same level of security as they would normally have with wired solutions. Secure communications is an important part of the overall security of industrial wireless communications systems (IWCS). The aim of this thesis is to develop new security engineering methodologies for IWCS. The author develops countermeasures against confidentiality and integrity attacks and carries out a security analysis covering the protocol, electromagnetic and physical layer. In the first part of the thesis, Host Identity Protocol (HIP) is utilized to secure communication in an intra–vehicular network. Simulations and measurement campaigns are also conducted to evaluate the impact of the overhead on security in a tunnel, considering line–of–sight (LOS) and non–LOS (NLOS) scenarios. Electromagnetic analysis (EMA) is an important step in the development of safety–related systems. Today, the increasing usage of smaller integrated circuit also increases the susceptibility to electromagnetic (EM) interference. From near–field (NF) to far–field (FF) transformation, a method for the evaluation of the emissions leakage is investigated. The virtual EM (VEM) interface of the device–under–test (DUT) is studied, and it is described how an adversary can exploit it for denial of service (DoS) attacks. An effective jamming attack model is studied, and the theoretical calculations are validated with experiment–based results. Finally, focusing attention on physical layer security, two algorithms are developed. Active radio frequency fingerprinting (RFF) implements the exchange of a public key during the setup of secure communication. Afterwards, utilizing a jamming receiver in conjunction with the spread spectrum (SS) watermarking technique, the watermark–based blind physical layer security (WBPLSec) protocol is presented. The analysis and results indicate how the WBPLSec seems to be a valuable technique for deploying physical layer security by creating a secure region around the receiverTiivistelmä Langattoman tietoliikenteen maailmanlaajuista suosiota kiihdytti alun perin mahdollisuus korvata tietoliikennejärjestelmissä käytetyt kaapelit langattomilla ratkaisuilla. Ilmiö lisäsi myös tarvetta kehittää alan turvatekniikkaa monialaisen tutkimuksen pohjalta. Vaikka langattomat ratkaisut merkitsevät pienempiä asennuskustannuksia ja tarjoavat mahdollisuuksia luoda uudenlaisia palveluja, järjestelmien loppukäyttäjät edellyttävät kuitenkin niiden turvallisuuden olevan vastaavalla tasolla kuin langallisissa verkoissa. Myös teollisuuden langattomien tietoliikennejärjestelmen turvallisuus riippuu pitkälti viestintäkanavien turvallisuudesta. Väitöksen tavoitteena on kehittää uusia menetelmiä, joilla teollisuuden langattomat tietoliikennejärjestelmät voitaisiin turvata. Väitöksessä kehitetään toimenpiteitä tietoliikennejärjestelmien luottamuksellisuuteen ja koskemattomuuteen kohdistuvia hyökkäyksiä vastaan ja toteutetaan turvallisuusarviointi, joka kattaa järjestelmän protokollakerroksen sekä sähkömagneettisen ja fyysisen kerroksen. Väitöksen ensimmäisessä osassa hyödynnetään HIP–protokollaa (Host Identity Protocol) liikennevälineen sisäisen tietoliikennejärjestelmän turvallisuuden varmistamisessa. Lisäksi siinä kuvataan simulaatiot ja mittaushankkeet, joiden tavoitteena on arvioida käytetyn protokollan turvallisuusvaikutuksia esteettömän (line–of–sight, LOS) ja esteellisen (non–line–of–sight, NLOS) näköyhteyden tapauksissa. Sähkömagneettinen analyysi on tärkeä vaihe turvajärjestelmien kehitysprosessissa. Järjestelmissä käytetään yhä enemmän pieniä integroituja piirejä, mikä voi myös altistaa ne sähkömagneettisille (electromagnetic, EM) häiriöille. Väitöksessä tutkitaan lähikenttä–kaukokenttä -muunnokseen perustuvan arviointimenetelmän avulla sähkömagneettisen vuotosäteilyn tasoa. Lisäksi perehdytään testattavan laitteen (device under test, DUT) virtuaaliseen EM–liitäntään ja kuvataan, miten vastaavaa liitäntää voidaan hyödyntää palvelunestohyökkäyksissä. Väitöksessä tutkitaan myös tehokasta häirintämallia ja validoidaan teoreettisten laskelmien tulokset kokeellisesti. Lopuksi väitöksessä keskitytään tietoliikennejärjestelmän fyysisen kerroksen turvallisuuteen ja kehitetään kaksi algoritmia. Aktiivisen radiotaajuisen tunnistusmenetelmän avulla voidaan vaihtaa julkisia avaimia turvallista tietoliikenneyhteyttä muodostettaessa. Lisäksi esitellään vesileimausmenetelmään perustuva fyysisen kerroksen salausmenetelmä, WBPLSec. WBPLSec luo vastaanottimen ympärille suoja–alueen, minkä ansiosta se vaikuttaa analyysin ja tutkimustulosten perusteella olevan tehokas menetelmä toteuttaa fyysisen kerroksen suojaus
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Joubert-Wallis, Marie. "The contribution of culture to the spread of HIV." Diss., 2008. http://hdl.handle.net/10500/647.
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Cultural factors have been shown to play a role in human decision making and behaviour. The main objective for this research was to identify and evaluate the possible influence of Shangaan cultural beliefs, myths and behaviours, on the spread of HIV within the Mnisi tribe. A qualitative method of investigation was followed; interviews with three participants and observations of the Mnisi culture were used in the construction of the investigation and findings. Through the information obtained two cultures influencing the spread of HIV in the Mnisi tribe were identified, they are (1) The culture of power-rule and fear, and (2) The culture of poverty.Psychology
M.Sc. (Psychology)
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Hertog, Sara Elizabeth. "Patterns of sexual activity and the spread of HIV/AIDS." 2004. http://catalog.hathitrust.org/api/volumes/oclc/56201960.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 2004.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 37-43).
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Desmond, Chris. "The dual role of income in the spread of HIV in Africa." Thesis, 2002. http://hdl.handle.net/10413/4619.
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Every day more people in Africa are infected with HIV despite prevention efforts. These new infections and those already infected are not evenly spread throughout the continent. Substantial variations in HIV prevalence exist within and between countries. Understanding these variations helps understand what is driving the epidemic and this understanding in turn helps in the design of more appropriate interventions to prevent its further spread. This thesis builds on existing work by attempting to develop a more
comprehensive theory of what role income plays in the spread of HIV. To this end the Theory of the Dual Role of Income in the Spread of HIV is outlined and explained. It uses the concepts of relative and absolute income, borrowed from elsewhere in the health economics literature, to separate the different effects income has on individual and group risk of HIV infection. The theory hypothesises that, while higher levels of absolute
income (income independent of others) offer protection against infection via better access to health care and information, higher relative income (the income of an individual relative to other members of their social or reference group) increases risk of infection either as a result of more sexual partners or higher risk partners. The theory in no way argues that HIV infections are not related to poverty, but rather that the relationship is,
somewhat more complicated and non-linear than often suggested. The explanatory power of the theory is examined with the use primarily of two data sets: firstly using data collected from antenatal clinics in two South African provinces linked with census data and secondly with data on a large South African company. While these data are not ideal, the results from the analysis are in line with the expectations based on the theory.
The theory and the results of the analysis presented in this thesis support the argument that environments in which decisions are made and actions taken are important in determining risk of HIV infection. This argument suggests that prevention efforts need to do more then provide information.Thesis (M.Com.)-University of Natal, Durban, 2002.
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Moyo, Ntombizakhe. "Structural violence and the spread of HIV/AIDS among women in Bulawayo, Zimbabwe." Thesis, 2009. http://hdl.handle.net/10413/3852.
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The purpose of the study was to assess the impact of structural violence and the spread of HIV/AIDS among women and girls in Bulawayo. It is noted that the spread of HIV/ AIDS is high among women and girls in Bulawayo, similarly to the rest of the world. There have been a number of studies that were carried out seeking to find out what causes the spread among women, but it seems as if there has not been a substantial solution to the problem, as the rate of infection is still escalating. There has not been much work done in connection with the causes of the spread of HIV/AIDS among in Bulawayo. A qualitative method of collecting data was used; these are structured individual interviews and focus group interviews. An interview guide was designed for individual interviews, who were informants in the city working directly with affected and infected women. To complement the interviews, focus groups interviews were held with two groups of people, “Touch the Hem” (HIV) support groups and a group of commercial sex workers in the city. An interview guide was also designed for the focus group interview, based on issues that needed clarity and verification from the individual interviews. Permission was granted by individuals involved and ethical considerations of conducting the study were carefully considered. The findings of the study indicated that the spread of HIV among women is caused by high levels of concurrent sexual partners, early sex by girls with older men who are already infected with HIV, gender imbalances, commercial sex work, domestic violence, imbalances in sexual relationships, lack of health information and poverty. It was indicated by the findings of this study that some of these causes have links with structural violence. It is recommended that both men and women should be educated on health and HIV related issues, and that exploitative and unjust, cultural, political and socioeconomic structural systems should be eradicated in order to establish positive peace.Thesis (M.Com.)-University of KwaZulu-Natal, Westville, 2009.
HEARD Division.
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Moyo, Nolipher Jere. "The influence of cultural practices on the spread of HIV and aids on Zambian people." Thesis, 2010. http://hdl.handle.net/2263/26813.
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In a BBC radio report last year, one speaker reported that Africa South of the Sahara is the worst affected by the HIV and AIDS pandemic. Is it that African Christians are more promiscuous than say their European and American counterparts? After living in U.S.A. myself and after having traveled in Europe, I felt that the truth of the matter may be the direct opposite. It may be that apart from sex there must be other ways through which HIV and AIDS is spreading in Southern Africa. Things like rites of passage and other African cultural practices may be what have made HIV and AIDS to find a fertile soil in Southern Africa. There have been a number of women who are infected with the HIV and AIDS virus in Zambia and Africa as a whole (UNICEF reports on Zambia 2003). Women are more vulnerable to AIDS than men in Zambia for a number of reasons, some of which are the collapse of the support systems leading to poverty, the dying of African moral values, etc. Therefore there is a need to intensify our efforts to find out the relationship between cultural practices in rites of passage and the spread of HIV and AIDS in patrilineal and matrilineal Zambian cultures? To promote effective joint involvement into finding the solution to this problem the following objectives will be achieved: To explore the salient cultural practices of rites of passage which promotes and hinders the spread of HIV and AIDS in Zambian women and the people of Zambia, to explore through a narrative approach, cultural practices and gender, to collect stories of women who have been the victims of these cultural practices, to look at rites of passage, a theological reflection. Since culture plays a major role in people’s lives in Zambia and Africa as a whole, there is need to take Zambian or African culture seriously so that we can look at the salient cultural practices in rites of passage which influence the spread of HIV and AIDS.Thesis (PhD)--University of Pretoria, 2010.
Practical Theology
unrestricted
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Chetty, Parvathie. "Gendered sexual vulnerabilities in the spread of HIV/AIDS : Clayfield (Phoenix) as case study." Thesis, 2007. http://hdl.handle.net/10413/5232.
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This dissertation focuses on how important factors such as gender inequalities and gender vulnerabilities contribute to fuelling the spread of HIV/AIDS. The study focuses on a community in Phoenix, called Clayfield. The study examines aspects of masculinity, sexual relations, socio-economic vulnerabilities and domestic violence and demonstrates how these elements predispose women and girls to HIV infection. As a result of gender inequalities and imbalances, women are vulnerable to HIV infection. The study also explores how risky behaviour, by both men and women, can escalate women's vulnerability to the disease. The central argument engages discussion on crucial issues around gender imbalances and vulnerabilities. The study concludes with recommendations pertinent to challenging present gender-based initiatives and interventions, and suggests possible gender-sensitive strategies that could assist in curbing the spread of the disease.Thesis (LL.M.)-University of KwaZulu-Natal, Westville, 2007.
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Velyvis, Kristen A. "The sexual networks of migrant Serere women and the spread of HIV in Senegal." 1998. http://catalog.hathitrust.org/api/volumes/oclc/41898916.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1998.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 80-83).
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West, Ronnie Webster. "Modeling the potential impact of HIV on the spread of tuberculosis in the United States." Thesis, 1995. http://hdl.handle.net/1911/16896.
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Tuberculosis (TB) was thought to be safely in decline in the United States in the mid 1980's as the number of cases dropped by 74% between 1953 and 1985. A wake-up call was issued in 1986 as an increase in TB incidence which could not be accounted for was reported. This upward trend has continued. At of the end of 1992, the CDC estimated that 39,000 more cases of TB had developed over the previous decade than if the declining trend present in the early 1980's had continued. This turnaround in TB is well correlated with the rise of the HIV epidemic. The severely depressed immune systems associated with HIV make individuals infected with the virus more likely to develop active TB than those who are not infected. Whereas susceptibles to HIV are generally confined to high risk groups such as homosexuals or intravenous drug users, this is not the case with TB. It may be that the development of the HIV epidemic has somehow tipped the balance in favor of a continued rise in TB within the United States.
The purpose of this work is to investigate through the use of mathematical models the magnitude and duration of the effect which the HIV epidemic may have on TB. Deterministic and stochastic models are developed which reflect the transmission dynamics of both TB and HIV, and the relative merits of these models are discussed. The deterministic models are then linked together to form a model for the combined spread of both diseases. A numerical study is performed to investigate the influence of certain key parameters. The effect which HIV will have on the general population is found to be dependent on the contact structure between the general population and the HIV risk groups as well as a possible shift in the dynamics associated with TB transmission. The development of a TB epidemic within the HIV risk groups is also considered.
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Chetty, Elzhaan. "Combating AIDS/HIV spread in the workplace : a case study of the Durban clothing industry." Thesis, 2002. http://hdl.handle.net/10413/4411.
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