The purpose of the study was to assess the impact of HIV/AIDS programmes at the workplace. The case study used both quantitative and qualitative methods (Triangulation) to determine the level of awareness and evaluate the impact of the programmes implemented at the workplace. The data was collected using a pilot tested structured questionnaire which was distributed to a purposive sample (n=60), involving all the departments at the company. Semi structured interviews involving purposively identified participants (n = 3) were conducted to clarify and explain issues in relation to questionnaire responses. The data from the structured questionnaire was analyzed using a statistical package for social sciences (SPSS).The findings revealed that the organization had achieved 90% awareness and 75% positive impact. The study also revealed that social background, individual values and religion influenced sexual behaviour, hence the recommendation for more preventive oriented programmes to influence positive behavioural change amongst employees / Health Studies / M.A. (Public Health)

This study aimed at evaluating the effectiveness of the 2011 to 2012 famine response in Somalia in saving lives and livelihoods, offering livelihood opportunities, supporting quick recovery and complying with accountability standards in the delivery of humanitarian assistance. Understanding the performance and effectiveness of the humanitarian response to emergencies such as the 2011 to 2012 famine in Somalia is important for managing similar large-scale disasters which tend to be more frequent than ever before. It is also vital for addressing the chronic food insecurity in sub-Saharan Africa. The study was conducted in the Dolow district, Gedo region, Somalia. The study was largely rooted in the qualitative paradigm even though quantitative methodologies were employed to explain certain aspects in order to adequately answer some of the research questions. The case study approach was employed to conduct this study and achieve the research objectives. Despite the need for more evidence-based and local community-driven response to droughts, the 2011 to 2012 famine response was largely relevant to meet the priority needs of affected populations. The response was too late to prevent the death of hundreds of thousands and the suffering of millions of people and the response had to struggle for quite some time to stabilise and reverse a devastating situation. Although the response was not adequate to cover the needs of all affected populations, it had a commendable impact by saving the lives of malnourished children and mothers; minimising suffering from lack of food, water and shelter; restoring livelihoods for host communities; and creating livelihood opportunities for internally displaced families. Compliance with the NGO Code of Conduct and the application of Sphere standards were fair. Strong accountability mechanisms are required to ensure effective beneficiary targeting and curb aid diversion. The beneficiaries of the response stated that they are equally vulnerable to droughts despite an increase in income and agricultural production as a result of the response. Long-term livelihood projects that address structural vulnerabilities and create multipleincome sources are essential for strengthening resilience to droughts. / Development Studies / M.A. (Development Studies)

Boilover is a violent ejection of certain liquid hydrocarbons due to prolonged burning during a storage tank fire. It happens due to vaporization of the water sub-layer that commonly resides at the base of a storage tank, resulting in the ejection of hot fuel from the tank, enormous fire enlargement, formation of a fireball and an extensive ground fire. Boilover is a very dangerous accidental phenomenon, which can lead to serious injuries especially to emergency responders. The boilover can occur several hours after the fuel in a storage tank caught fire. The delayed boilover occurrence is an unknown strong parameter when managing the emergency response operations. Modelling and simulation of the boilover phenomenon will allow the prediction of the important characteristics features of such an event and enable corresponding safety measures to be prepared. Of particular importance is the time from ignition to the occurrence of boilover. In order to establish a tool for the prediction of the boilover events, it is essential to understand what happens within the fuel during a fire. Such understanding is important in order to recognize and determine the mechanisms for the hot zone formation and growth which are essentials, especially for predicting the onset time of boilover. Accordingly, boilover experiments and tests were planned and carried out at field scale by the Large Atmospheric Storage Tank FIRE (LASTFIRE) project with the intentions to evaluate the nature and consequences of a boilover, and to establish a common mechanism that would explain the boilover occurrence. Undertaking field scale experiments, however, is difficult to carry out so often due to high costs and high safety concerns. In order to obtain more detailed measurements and visual records of the behaviour of the liquids in the pool, a novel laboratory scale rig has been designed, built and commissioned at Loughborough University. The vessels used in the field scale tests and the laboratory scale rig were instrumented with a network of thermocouples, in order to monitor the distribution in temperature throughout the liquid and its variation with time. The temperature distribution variation as a function of time enabled the recognition of the phases of the evolution of the hot zone and hence the mechanism of boilover. The rig has allowed well defined and repeatable experiments to be performed and hence enable to study and assess boilover in a reproducible manner. In addition, visualisation of the fuel behaviour during the experiments could be obtained to better understand the formation and growth of hot zone, the boiling of water layer and hence the boilover occurrence. A number of small and larger scale experiments had been completed to obtain a wide spectrum of results, evaluating the effect of tank diameters, fuel depth, and water depth on the rate and extent of the boilover. The analysis of the results had elucidated further the processes of the hot zone formation and its growth, and hence mechanisms involved in the boilover occurrence. The important observation was that there are three stages observed in the mechanism of boilover incidence. At the start of the fire there is a stage when the hot zone is formed. This is followed by a period when the bottom of the hot zone moves downwards at a pseudo constant rate in which the distillation process (vaporisation of the fuel s lighter ends) is taking place. The final stage involved the heating up of the lowest fuel layer consisting of components with very high boiling points and occurrence of boilover. Based on the observations of the mechanisms involved in the hot zone formation and its growth, predictive calculations were developed which focus on the provision of an estimate on the time to boilover upon the establishment of a full surface fire and an estimate of the amount of fuel remaining in the tank prior to the occurrence of the boilover. A predictive tool was developed in order to provide predictions on the important parameters associated with a boilover event i.e. the time to boilover, the amount of fuel remaining in the tank prior to boilover and hence the quantity of fuel that would be ejected during boilover and the consequences of a boilover i.e. fire enlargement, fireball effects and the ground area affected by the expulsion of oil during a boilover event. The predictive tool developed is capable of providing good estimates of onset time to boilover and predicts consequences of the boilover. The tool predicting the time to boilover of the LASTFIRE field scale test and the laboratory scales tests was shown to produce predictions that correlated with the observed time to boilover. Apart from the time to boilover, the predictive calculation is also able to provide an estimate of fuel amount remained in the tank at the instance of boilover occurrence. Consequently, the tool is capable of predicting the quantity of burning fuel being ejected and hence the area affected by the extensive ground fire surrounding the tank. The predictive results are conservatives but yet show good agreement with observed time to boilover in real boilover incidents. Certain considerations in the development of safe and effective fire fighting strategies in handling fire scenario with a potential of boilover occurrence, can be assessed using the predictive tool developed.

Super Duplex Stainless Steels have superior corrosion resistance properties and strength compared to conventional steels. However, these properties are influenced by the different phases that precipitate during the heat treatment process. The conventional way of studying the time and temperature effects on the properties and micro-structure of SDSS is to prepare many samples at different temperatures and holding times. The welding research group at Production Technology Center, Trollhättan, Sweden, has recently developed a unique heat treatment method to produce a wide range of temperature by using a stationary TIG arc heat source. It results in a graded micro-structure in a single sample at a specific time period. The accuracy of the results ob-ained from this process is highly related to the accuracy of the temperature field model next to weld pool. In this work, a model was developed by using OpenFOAM CDF code, to predict the temperature field of the super duplex stainless steel samples that have been subjected to this novel TIG arc heat treatment process. The developed model was able to capture the trend in the overall temperature field in the heat affected zone. However, there was some mismatch between the modelled and experimental temperature profiles in certain locations in the heat affected zone. Further improvements have to be done to the developed model in order to take the phase transformation effect into account. A preliminary investigation has been carried out on how to implement this in the current model and reported in the thesis.

Supracrystals are highly symmetrical ordered superstructures built up from nanoparticles via self-assembly. While the NP assembly has been intensively investigated, the formation mechanism is still not understood. To shed some light onto the formation mechanism, we are using one of the most common supracrystal morphologies, the trigonal structures, as a model system to investigate the formation process in solution. To explain the formation of the trigonal structures and determining the size of the supracrystal seeds formed in solution, we introduce the concept of substrate-affected growth. Furthermore, we show the influence of the NP concentration on the seed size and extend our investigations from Ag towards Au. 1.

O objetivo do presente estudo foi avaliar o efeito da biomodificação com carbodiimida e quitosana fosforilada na dentina afetada por cárie. A amostra foi composta por 75 espécimes de dentina bovina submetidos à indução de lesão de cárie pelo método de ciclagem do pH (8h em solução desmineralizante e 16h em solução remineralizante) durante 14 dias. Foi realizada a remoção seletiva da lesão de cárie com broca em baixa rotação. Os espécimes foram divididos de acordo com a biomodificação da dentina: sem biomodificação (controle), carbodiimida (EDC) e quitosana fosforilada (P-chi). Os espécimes foram condicionados com ácido fosfórico 35%, e tratados com o agente biomodificador correspondente. Os espécimes foram restaurados com adesivo (Single Bond Universal - 3M ESPE) e resina composta (Z250 - 3M ESPE). Trinta espécimes foram submetidos à análise de microdureza da subsuperfície dentinária em quatro momentos: dentina hígida, dentina afetada por cárie, após a remoção seletiva da lesão de cárie (dentina residual) e, após a restauração dos espécimes. Os 36 espécimes restantes foram submetidos a ensaio de resistência de união à microtração (&mu;TBS) realizado após 24 h e 6 meses de armazenamento em água e microscopia eletrônica de varredura (MEV). Os dados foram analisados por meio de testes paramétricos e não paramétricos (&alpha;=0,05). A biomodificação da dentina residual afetada por cárie com EDC e P-chi não alterou a microdureza da subsuperfície dentinária (p=0,141). Na análise de &mu;TBS, não foram encontradas diferenças significativas entre os grupos 24 h e após 6 meses de armazenamento. Ao longo do tempo, o grupo controle (p<0,001) teve redução da &mu;TBS, o grupo EDC (p=0,099) foi capaz de manter a &mu;TBS e o grupo P-chi (p=0,005) promoveu aumento da &mu;TBS. A análise de MEV mostrou que os biomodificadores preservaram a interface adesiva após 6 meses de armazenamento. A biomodificação com carbodiimida e quitosana fosforilada não influenciou a microdureza da subsuperfície da dentina afetada por cárie, porém foi capaz de inibir a degradação da interface adesiva, mantendo a resistência de união da resina composta à dentina afetada após 6 meses de armazenamento em água / The aim of this study was to evaluate in vitro the effect of biomodification with carbodiimide and phosphorylated chitosan on caries affected dentin. The sample was composed by 75 bovine incisors, submitted to caries induction by pH cycling (8h in demineralizing solution and 16h in remineralizing solution) for 14 days. The selective caries removal was performed with bur at low-speed handpiece. Specimens were divided according to the dentin biomodification: no biomodification (control), carbodiimide (EDC) and phosphorylated chitosan (P-chi). All specimens were conditioned with 35% phosphoric acid and then treated with the correspondent biomodificator. Specimens were restored with an adhesive system (Single Bond Universal - 3M ESPE) and composite resin (Z250 - 3M ESPE). Thirty specimens were submitted to subsurface microhardness test in four periods of time: on sound dentin, on caries-affected dentin, after the selective removal of caries (residual caries-affected dentin) and after the restoration. The remaining 36 specimens were submitted to microtensile bond strength test (&mu;TBS) after 24 h and 6 months of water storage and to scanning electron microscopy analysis (SEM). Data were statistically analyzed by parametric and non-parametric tests (&alpha;=0.05). The biomodification of residual caries-affected dentin with EDC and P-chi did not change the subsurface microhardness (p=0.141). In the &mu;TBS test, there were no significant difference between groups at 24 h and 6 months of water storage. Over time, the control group (p<0.001) had a decreased on the &mu;TBS, the EDC group (p=0.099) was capable of maintained &mu;TBS and the P-chi group (p=0.005) increased in &mu;TBS. SEM analysis showed that biomodification preserved the adhesive interface after 6 months of water storage. The biomodification with carbodiimide and phosphorylated chitosan did not influence the subsurface microhardness of caries-affected dentin, however, it was capable of inhibit degradation of the adhesive interface, maintaining the microtensile bond strength of the composite resin to caries affected dentin after 6 months of water storage

Student Number : 0105964W - MPH research report - Faculty of Health Sciences / The Employment Bureau for Africa (TEBA Limited) established in 1902 recruits mineworkers from Lesotho and neighbouring countries for South African mines. Information on mineworkers’ health and welfare from Lesotho is scarce. Tuberculosis prevalence ranged between 159/100000 and 506/100000 from 1991 to 2001 in Lesotho. This cross-sectional study aimed to determine the proportion of mineworkers affected with tuberculosis among adult male patients attending TB clinics in Maseru District’s three main hospitals and ascertain compensation of mineworkers affected by occupational lung disease including tuberculosis. A structured questionnaire was used to interview 421 adult male TB patients at Queen Elizabeth II, Saint Joseph and Scott hospitals in Maseru. 38.5% of participants in the study were mineworkers (former and active) in South African mines. Among these mineworkers, 70.4% were employed in goldmines. 30.7% of mineworkers were considered eligible for compensation. 42 mineworkers received compensation for previous and current tuberculosis whilst 33 mineworkers had not.

Este estudo se propôs a validar um protocolo para obtenção de dentina afetada por cárie, através do processo in vitro de desmineralização de dentina humana induzida por biofilme de Streptoccocus mutans (método microbiológico). A validação do protocolo foi realizada através de diferentes métodos diagnósticos: inspeção visual, radiografia digital, fluorescência a laser e sistema de tomografia por coerência óptica (OCT). Foram utilizados 48 molares humanos (24 erupcionados e 24 inclusos), que foram lixados na sua face oclusal para remoção do esmalte com exposição da dentina oclusal superficial, obtendo uma superfície plana. As raízes dos dentes foram removidas e os espécimes foram cortados no sentido vestibulo-lingual obtendo-se dois fragmentos que foram distribuídos aleatoriamente nos grupos experimentais. Os espécimes foram protegidos com verniz ácido resistente na metade da face oclusal (controle) e na outra metade foi produzida a lesão de cárie. Os grupos experimentais foram compostos a partir de 2 fatores de variação: tempo de desafio cariogênico (7, 14 e 21 dias) e tipo de dentina (proveniente de dentes inclusos ou erupcionados). Assim, formaram-se 6 grupos experimentais: com dentina proveniente de dentes erupcionados G1 (7 dias de desafio cariogênico), G2 (14 dias), G3 (21 dias); e com dentina proveniente de dentes inclusos G4 (7 dias), G5 (14 dias) e G6 (21 dias). Após os diferentes tempos de desafio cariogênico, os espécimes foram avaliados nas suas porções sadia e afetada por cárie utilizando diferentes métodos de diagnóstico e os resultados comparados. Através da inspeção visual comprovou-se a formação de dentina afetada por cárie uma vez que características do tecido como coloração amarelada, perda de brilho superficial e consistência borrachóide foram observadas. A radiografia digital foi capaz de detectar a presença de imagem sugestiva de lesão de cárie através de imagem radiolúcida. Três examinadores calibrados visualizaram todas as imagens obtidas através da inspeção visual e da radiografia digital e foram capazes de distinguir o tecido hígido do afetado por cárie. Foi aplicado o teste estatístico Exato de Fischer com nível de significância de 5% que confirmou não haver diferença entre os grupos tanto na inspeção visual (G1 e G4 - p=0,6, G2 e G5 - p=1 e G3 e G6 - p=1)como para a radiografia digital (G1 e G4 - p=1, G2 e G5 - p=1 e G3 e G6 - p=1). Tanto os valores de fluorescência a laser quanto os de profundidade de desmineralização (OCT) foram submetidos ao teste estatístico Análise de Variância (ANOVA) (p<0,05). Em relação aos valores obtidos via fluorescência a laser, pode-se observar que houve diferença estatisticamente significante para o fator tipo de substrato (p=0.001), sendo que os espécimes provenientes de dentes erupcionados apresentaram maior valor de fluorescência em relação aos espécimes provenientes de dentes inclusos. Quanto ao OCT, pode-se observar que não houve diferença estatisticamente significante para o fator tipo de substrato (p=0,163), para o fator tempo de desafio cariogênico (p=0,512) e para a interação entre os fatores (p=0,148). Por fim, eletromicrografias foram obtidas através de Microscopia Eletrônica de Varredura que confirmaram a presença do tecido afetado por cárie produzido artificialmente em todos os tempos de desmineralização testados, no entanto observou-se desmineralização superficial mais uniforme em dentina afetada por cárie proveniente de dentes inclusos. Assim, podemos concluir que 7 dias de desafio cariogênico é suficiente para obtenção de dentina afetada padronizada a ser utilizada em ensaios laboratoriais e que dentes inclusos forneceram um substrato dentinário mais adequado para utilização no protocolo proposto. / The aim of this in vitro study was to validate a protocol for obtaining standard caries affected-dentine by dentine demineralization process induced by Streptoccocus mutans biofilm (microbiological approach). Validation methods performed were optical coherence tomography (OCT), visual inspection, laser fluorescence and digital radiography. As all methods were nondestructive, all analysis were performed in the same specimens. A total of 48 human molars (24 erupted and 24 unerupted) were grounded in the occlusal surface to remove enamel and obtain a flat dentin surface. The roots of the teeth were removed and the specimens were cut in the bucco-lingual direction yielding two fragments that were randomized into experimental groups. The dental fragments were protected with acid resistant varnish in half of the occlusal surface (control) and in the other half was produced carious lesions. The experimental groups were composed from two variation factors: period of cariogenic challenge (7, 14 and 21 days) and type of dentin (from erupted or unerupted teeth). Thus six experimental groups were formed: with dentin from erupted teeth - G1 (7 days of cariogenic challenge), G2 (14 days), G3 (21 days), and with dentin from unerupted teeth - G4 (7 days), G5 (14 days) and G6 (21 days). After different periods of cariogenic challenge, the specimens were evaluated on their healthy and caries-affected portions using different diagnostic methods and the results were compared. Visual inspection proved the formation of caries affected dentin as characteristics of the tissue as yellowing, loss of surface gloss and consistency elastic were observed. The digital radiography was able to detect the presence of radiolucent image, suggesting caries. Three calibrated examiners viewed all the images obtained by visual inspection and digital radiography, and were able to distinguish healthy from caries affected dentin. We used the Fisher exact statistical test with a significance level of 5% which confirmed no difference between groups in both visual inspection (G1 and G4 - p=0.6; G2 and G5 - p=1 and G3 and G6 - p=1) and digital radiography (G1 and G4 - p=1, G2 and G5 - p=1 and G3 and G6 - p=1). Both laser fluorescence values and depth of demineralization (OCT) were subjected to statistical test Analysis of Variance (ANOVA) (p<0.05). Regarding the values obtained by laser fluorescence, a statistically significant difference can be observed for the factor type of substrate (p=0.001), with the erupted teeth specimens with higher fluorescence compared to specimens from unerupted teeth. For OCT, we can observe that there was no statistically significant difference for the factor type of substrate (p=0.163), for the factor length of cariogenic challenge (p=0.512) and interaction between factors (p=0.148). Finally, photomicrographs were obtained by scanning electron microscopy which confirmed the presence of caries affected tissue produced artificially at all demineralization times tested, however a more uniform demineralization surface was observed in caries affected dentin of unerupted teeth. Thus, we conclude that 7 days of cariogenic challenge is sufficient to obtain standard caries affected dentin to be used in laboratory tests and unerupted teeth provided a more suitable substrate for use in this proposed protocol.

<p>Cervical cancer is a multifactorial disease. Infection by oncogenic types of the human papillomavirus (HPV) is the major environmental risk factor and host genetic susceptibility also influences disease development. </p><p>The aim of this thesis is to identify and analyse risk genes involved in the genetic predisposition to cervical carcinoma. A unique and extensive population-based affected sib-pair (ASP) material and a large case-control sample were used in the investigations.</p><p>In paper I the human leukocyte antigen (HLA) class II DQB1 and DRB1 loci are confirmed, for the first time in a family-based material, as genetic susceptibility factors for cervical cancer. It is also proposed that the HLA class II DPB1 locus independently contributes to risk of developing disease. In addition, no evidence is found for an involvement of the class I HLA-B and HLA-A loci in the genetic predisposition. Paper II conclude that the Fas receptor –670 single nucleotide polymorphism (SNP) do not have a major impact on the susceptibility to cervical carcinoma <i>in situ</i> in the Swedish population. In paper III we show that interactions between the HPV16 E6 gene subtype and host HLA class II genotype potentially occur during infection and disease progression. Paper IV suggests that three chromosomal regions, 9q32, 12q24 and 16q24, contain risk factors of low to moderate effects on cervical cancer development. In paper V linkage signals are further identified between a 9q32 gene encoding the thymic stromal co-transporter (TSCOT) and the disease in ASPs with mean age over 30.5 years at diagnosis within the sib-pair.</p><p>These findings are important contributions towards understanding more about the aetiology of this complex cancer. The identification of new susceptibility regions opens up for further characterisation, replication and candidate gene analysis.</p>

With increasing miniaturization in microelectronics the wirebonds used in IC packages are witnessing a thrust towards fine pitch wirebonding. To have a precise control over loop height of the wirebond for fine pitch wirebonding, it is imperative to do mechanical characterization of the wirebond. The present work studies the mechanical properties of gold wire and wirebond using nanoindentation. The wirebond specimen surface was planarized using mechanical polishing. The loop height of the gold wirebond is directly proportional to the length of the heat affected zone (HAZ) above the ball of gold wirebond. Metallographic preparation of gold wirebond cross section reveals the presence of undesirable coarse grain structure in HAZ due to recrystallization and grain growth in the gold wire adjacent to the ball. The recrystallization temperature of our gold wire was found using D.S.C. to be 340.66°C. The doping elements present in the gold wire used, were identified using TOF-SIMS. Nanoindentation of the gold wire was done at different maximum loads to observe the hardness variation with load. The nanoindentation of gold wirebond has confirmed a v-shaped hardness profile in the HAZ. The hardness minima for the particular gold wire used with a ball size ratio of 2.4 was observed at distance of 160-170 µm from the neck of the ball. The elastic modulus was found to vary randomly and to be independent of the microstructure in the wirebond. A yield stress profile based on empirical hardness-yield strength correlation has been predicted for the gold wirebond. / Singapore-MIT Alliance (SMA)