Submitted by Caroline Falcao (caroline.rfalcao@ufpe.br) on 2017-05-09T15:34:24Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Saulo Felipe Costa.pdf: 1452357 bytes, checksum: 0b48a353adb96d0a477a32d1fef74fe7 (MD5) / Made available in DSpace on 2017-05-09T15:34:24Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Saulo Felipe Costa.pdf: 1452357 bytes, checksum: 0b48a353adb96d0a477a32d1fef74fe7 (MD5) Previous issue date: 2012 / Esta dissertação teve como objetivo examinar a existência de ciclos políticos eleitorais na América Latina no período democrático recente. Mais especificamente examina-se a influência dos ciclos eleitorais sobre os resultados macroeconômicos latino-americanos no período 1994-2011, que foi marcado pela globalização e pela consolidação da democracia na região. Para tanto, esta pesquisa baseou-se em dados secundários de dezoito países da América Latina – Argentina, Bolívia, Brasil, Chile, Colômbia, Costa Rica, Equador, El Salvador, Guatemala, Honduras, México, Nicarágua, Panamá, Paraguai, Peru, República Dominicana, Uruguai e Venezuela – e teve o intuito de verificar se as teorias dos ciclos político econômicos forneceriam uma resposta para o padrão encontrado nestes países no período analisado de 1994 a 2011. Os resultados obtidos pela pesquisa não identificaram influência do período eleitoral sobre as variáveis selecionadas, contrariando as expectativas teóricas do modelo oportunista. No que diz respeito às expectativas do modelo partidário, os resultados não foram conclusivos, sendo significantes apenas em alguns modelos econométricos e para algumas orientações ideológicas. O padrão encontrado aponta ainda uma relevância das variáveis de abertura econômica e variação no preço de commodities, indicando que a globalização destas economias vem impactando em seus indicadores macroeconômicos, apontando que a globalização e a integração dos mercados financeiros vêm favorecendo a disciplina fiscal ao punirem estratégias oportunistas. / This dissertation aimed to examine the existence of political electoral cycles in Latin America in recent democratic period. More specifically examines the influence of electoral cycles on macroeconomic outcomes in Latin America in the period 1994-2011, which was marked by globalization and consolidation of democracy in the region. To this end, this research was based on secondary data from eighteen Latin American countries - Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Dominican Republic, Uruguay and Venezuela - and aimed to verify the theories if political economic cycles would provide a response to the pattern found in these countries during the period analyzed from 1994 to 2011. The results obtained by the survey did not identify the influence of the electoral period on the selected variables, contrary to theoretical expectations of the opportunistic model. With regard to the expectations of the party model, the results were not conclusive, being significant only in some econometric models and some ideological orientations. The pattern found also indicates a relevance of the variables of economic liberalization and changes in commodity prices, indicating that the globalization of these economies is impacting on its macroeconomic indicators, pointing out that globalization and integration of financial markets has favored fiscal discipline to punish opportunistic strategies.

Submitted by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-11T16:13:39Z No. of bitstreams: 2 Dissertação - Solange Moreira da Silva - 2012.pdf: 2785230 bytes, checksum: 7aaa8506c7565237cf88ab856e88a595 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-11T20:03:28Z (GMT) No. of bitstreams: 2 Dissertação - Solange Moreira da Silva - 2012.pdf: 2785230 bytes, checksum: 7aaa8506c7565237cf88ab856e88a595 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-11T20:03:28Z (GMT). No. of bitstreams: 2 Dissertação - Solange Moreira da Silva - 2012.pdf: 2785230 bytes, checksum: 7aaa8506c7565237cf88ab856e88a595 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2012-12-12 / Oral manifestations are common in Human Immunodeficiency Virus (HIV) infected individuals and are present at any moment of this morbidity. They are caused by opportunistic agents like fungus, virus or bacteria and neoplasms occur sometimes. The objective of this study was to develop a systematic literature review to know about the prevalence for oral manifestations related to HIV infection and to verify their occurrence in patients infected with HIV, followed at Sistema Único de Saúde, associated factors and side effects related to antirretroviral therapy. Initially was developed a systematic literature review to answer about oral manifestation prevalence and their meaning in HIV infection. Simultaneously an observational study was initiated including 201 HIV infected patients regulated by the Sistema Único de Saúde. These patients were currently attended at the Ambulatory of Infectology from Hospital das Clínicas of Universidade Federal de Goiás. All the participants were submitted to an oral examination which permitted a presumptive diagnostic based on international criteria of The EC Clearinghouse on Oral manifestations for HIV infection recommended by The World Health Organization. They also answered to a structured formulary e data were collected from the medical records. Characteristics lesions were photographed. The systematic literature review identified 337 papers. Only 20 were finally included after Relevance Tests I and II. These papers revealed a prevalence for oral manifestations related to HIV ranging from 19, 5% to 85,0%. Candidosis and oral hairy leucoplakia were the most prevalent lesions and they have been considered as immunologic markers for disease progression and therapeutic failure. The statistical analyse were descriptive and univariate logistic regression surveyed associations between oral manifestations related to human immunedeficiency virus infection and sociodemographic datas, CD4+ counting, time of disease, use of antiretroviral therapy, prosthesis usage and presence of carie lesion. Fisher’s exact test was applied to comparisons. At the observational study we found a low prevalence for these lesions with significant difference between groups HIV+ and AIDS. There were 5,40% of periodontitis related to HIV infection in the Group I and 11,00% in the Goup II. Neoplasms were not found. The most common side effect for antiretroviral therapy was dry mouth (7,60% at the HIV Group and 11,00% at the AIDS Group). There was statistical significant association between oral lesion occurrence and carie presence (AIDS Group) or use of prosthesis and age (HIV Group). From the systematic literature review we concluded that oral manifestations are common in HIV+/AIDS patients and candidosis and oral hairy leucoplakia are immunologic markers for the disease progression and Abstract xx therapeutic failure. From the observational study we concluded that the prevalence verified was relatively short. Periodontal diseases were the most common lesions. Age and prosthesis use were associated to oral manifestations occurrence at the HIV Group and carie lesions also influenced at the AIDS Group. / As manifestações bucais em indivíduos infectados pelo Virus da Imunodeficiência Humana (HIV) são comuns e estão presentes em algum momento da infecção. Causadas por germes oportunistas como fungos, bactérias e vírus, podem resultar até mesmo em lesões malignas. Este estudo objetivou realizar uma revisão sistemática da literatura científica para investigar a prevalência das manifestações bucais relacionadas ao HIV em pacientes infectados por este vírus e verificar a ocorrência das mesmas em pacientes atendidos pelo Sistema Único de Saúde, possíveis fatores associados e efeitos adversos bucais relacionados ao uso de antirretrovirais. Inicialmente uma revisão sistemática da literatura verificou a prevalência destas lesões e sua importância no curso da doença. Simultaneamente foi desenvolvido um estudo observacional incluindo 201 pacientes infectados pelo HIV, sendo 92 pertencentes ao Grupo I (HIV+) e 109 pertencentes ao Grupo II (AIDS), regulados pelo Sistema Único de Saúde, atendidos no Ambulatório de Infectologia do Hospital das Clínicas da Universidade Federal de Goiás. Todos os participantes foram submetidos a exame da cavidade bucal e o diagnóstico presuntivo das manifestações bucais foi baseado em critérios internacionais do European Community – Clearinghouse recomendado pela Organização Mundial de Saúde. A seguir, todos responderam a um formuário estruturado do estudo e dados foram coletados dos prontuários médicos. Lesões consideradas relevantes foram fotografadas. Na revisão sistemática, dos 337 artigos científicos identificados, apenas 20 atenderam aos critérios de inclusão retratando uma variação na prevalência de lesões orais entre 19,50% a 85,00%. Nesta revisão, a candidose e a leucoplasia pilosa foram as mais lesões bucais mais prevalentes, consideradas marcadores da progressão da doença e de falência terapêutica. No estudo observacional a análise estatística foi descritiva e a verificação de associações entre a ocorrência de manifestações bucais relacionados à infecção pelo vírus da imunodeficiência humana e dados sóciodemográficos, contagem de CD4+, tempo de doença, uso de terapia antirretroviral, uso de prótese e presença de lesão de cárie foi realizada por meio de regressão logística univariada. Para comparações foi utilizado o teste exato de Fisher. No estudo observacional, foi encontrada uma prevalência de 19,60% para o grupo I e de 33,00% para o Grupo II para as manifestações bucais relacionadas ao HIV. Verificou-se diferença estatisticamente significante entre os dois grupos. Houve uma prevalência de 5,40% de periodontite relacionada ao HIV no Grupo I e 11,00% no Grupo II. Não foram encontradas lesões malignas. O efeito adverso bucal relacionado ao uso de antirretroviral mais comum nos dois grupos foi xerostomia (7,60% no Grupo HIV e 11,00% no Grupo AIDS). Houve associação estatisticamente significante entre a ocorrência de lesões bucais e a presença de cárie (Grupo AIDS) e idade e uso de prótese (Grupo HIV). Da revisão sistemática da literatura conclui-se que estas manifestações são comuns nos pacientes HIV+/AIDS e que candidose e leucoplasia pilosa bucal são marcadores imunológicos da doença e de falência terapêutica. Do estudo observacional concluímos que a prevalência de manifestações bucais relacionadas ao HIV foi relativamente baixa. As doenças periodontais relacionadas ao HIV foram as lesões mais prevalentes. Idade e uso de prótese foram fatores influenciadores na ocorrência dessas manifestações bucais no Grupo HIV. No Grupo AIDS, a presença de lesão de cárie influenciou na ocorrência dessas manifestações.

With online social networks such as Facebook and Twitter becoming globally popular, there is renewed interest in understanding the structural and dynamical properties of social networks. In this thesis we study several stochastic models arising in the context of the spread of influence or information in social networks. Our objective is to provide compact and accurate quantitative descriptions of the spread processes, to understand the effects of various system parameters, and to design policies for the control of such diffusions. One of the well established models for influence spread in social networks is the threshold model. An individual’s threshold indicates the minimum level of “influence” that must be exerted, by other members of the population engaged in some activity, before the individual will join the activity. We begin with the well-known Linear Threshold (LT) model introduced by Kempe et al. [1]. We analytically characterize the expected influence for a given initial set under the LT model, and provide an equivalent interpretation in terms of acyclic path probabilities in a Markov chain. We derive explicit optimal initial sets for some simple networks and also study the effectiveness of the Pagerank [2] algorithm for the problem of influence maximization. Using insights from our analytical characterization, we then propose a computationally efficient G1-sieving algorithm for influence maximization and show that it performs on par with the greedy algorithm, through experiments on a coauthorship dataset. The Markov chain characterisation gives only limited insights into the dynamics of influence spread and the effects of the various parameters. We next provide such insights in a restricted setting, namely that of a homogeneous version of the LT model but with a general threshold distribution, by taking the fluid limit of a probabilistically scaled version of the spread Markov process. We observe that the threshold distribution features in the fluid limit via its hazard function. We study the effect of various threshold distributions and show that the influence evolution can exhibit qualitatively different behaviors, depending on the threshold distribution, even in a homogeneous setting. We show that under the exponential threshold distribution, the LT model becomes equivalent to the SIR (Susceptible-Infected-Recovered) epidemic model [3]. We also show how our approach is easily amenable to networks with heterogeneous community structures. Hundreds of millions of people today interact with social networks via their mobile devices. If the peer-to-peer radios on such devices are used, then influence spread and information spread can take place opportunistically when pairs of such devices come in proximity. In this context, we develop a framework for content delivery in mobile opportunistic networks with joint evolution of content popularity and availability. We model the evolution of influence and content spread using a multi-layer controlled epidemic model, and, using the monotonicity properties of the o.d.e.s, prove that a time-threshold policy for copying to relay nodes is delay-cost optimal. Information spread occurs seldom in isolation on online social networks. Several contents might spread simultaneously, competing for the common resource of user attention. Hence, we turn our attention to the study of competition between content creators for a common population, across multiple social networks, as a non-cooperative game. We characterize the best response function, and observe that it has a threshold structure. We obtain the Nash equilibria and study the effect of cost parameters on the equilibrium budget allocation by the content creators. Another key aspect to capturing competition between contents, is to understand how a single end-user receives and processes content. Most social networks’ interface involves a timeline, a reverse chronological list of contents displayed to the user, similar to an email inbox. We study competition between content creators for visibility on a social network user’s timeline. We study a non-cooperative game among content creators over timelines of fixed size, show that the equilibrium rate of operation under a symmetric setting, exhibits a non-monotonic behavior with increasing number of players. We then consider timelines of infinite size, along with a behavioral model for user’s scanning behavior, while also accounting for variability in quality (influence weight) among content creators. We obtain integral equations, that capture the evolution of average influence of competing contents on a social network user’s timeline, and study various content competition formulations involving quality and quantity.

Magister Public Health - MPH / HIV support groups have been widely adopted as part of care and support interventions in Zambia, yet there is very little research on the effectiveness of these groups in meeting the needs of the PLWHIV from the perspective of those who join them. This case study looks at a selected support group for People Living with HIV and AIDS (PLWHIV) facilitated by the Flying Angels, a faith based non-governmental organization established in 2007 by the Living Assemblies of God Church, in Ng‟ombe Township, Lusaka. The Support Group brings together around eighty young and old, married and single, men and women living with HIV and AIDS, to share experiences and find ways of coping with their situation. The qualitative case study sought to obtain a rich understanding of the experiences of members with a view to understanding the support they needed, the aspects of the support group that are relevant and effective to their situation, and which are not. In-depth interviews and focus group discussions methods were used to collect data. Discussion and interviews were audio-taped. Audio-recordings were translated during transcription, data organized, coded and thematically analysed.

Data transmission has become a need in various fields, like in social networks with the diverse interaction applications, or in the scientific and engineering areas where for example the use of sensors to capture data is growing, or in emergency situations where there is the imperative need to have a communication system to coordinate rescue operations. Wireless networks have been able to solve these issues to a great extent, but what can we do when a fixed supporting infrastructure is not available or becomes inoperative because of saturation? Opportunistic wireless networks are an alternative to consider in these situations, since their operation does not depend on the existence of a telecommunications infrastructure but they provide connectivity through the organized cooperation of users. This research thesis focuses on these types of networks and is aimed at improving the dissemination of information in opportunistic networks analyzing the main causes that influence the performance of data transmission. Opportunistic networks do not depend on a fixed topology but depend on the number and mobility of users, the type and quantity of information generated and sent, as well as the physical characteristics of the mobile devices that users have to transmit the data. The combination of these elements impacts on the duration of the contact time between mobile users, directly affecting the information delivery probability. This thesis starts by presenting a thorough "state of the art" study where we present the most important contributions related to this area and the solutions offered for the evaluation of the opportunistic networks, such as simulation models, routing protocols, simulation tools, among others. After offering this broad background, we evaluate the consumption of the resources of the mobile devices that affect the performance of the the applications of opportunistic networks, both from the energetic and the memory point of view. Next, we analyze the performance of opportunistic networks considering either pedestrian and vehicular environments. The studied approaches include the use of additional fixed nodes and different data transmission technologies, to improve the duration of the contact between mobile devices. Finally, we propose a diffusion scheme to improve the performance of data transmission based on extending the duration of the contact time and the likelihood that users will collaborate in this process. This approach is complemented by the efficient management of the resources of the mobile devices. / La transmisión de datos se ha convertido en una necesidad en diversos ámbitos, como en las redes sociales con sus diversas aplicaciones, o en las áreas científicas y de ingeniería donde, por ejemplo, el uso de sensores para capturar datos está creciendo, o en situaciones de emergencia donde impera la necesidad de tener un sistema de comunicación para coordinar las operaciones de rescate. Las redes inalámbricas actuales han sido capaces de resolver estos problemas en gran medida, pero ¿qué podemos hacer cuando una infraestructura de soporte fija no está disponible o estas se vuelven inoperantes debido a la saturación de peticiones de red? Las redes inalámbricas oportunísticas son una alternativa a considerar en estas situaciones, ya que su funcionamiento no depende de la existencia de una infraestructura de telecomunicaciones sino que la conectividad es a través de la cooperación organizada de los usuarios. Esta tesis de investigación se centra en estos tipos de redes oportunísticas y tiene como objetivo mejorar la difusión de información analizando las principales causas que influyen en el rendimiento de la transmisión de datos. Las redes oportunísticas no dependen de una topología fija, sino que dependen del número y la movilidad de los usuarios, del tipo y cantidad de información generada y enviada, así como de las características físicas de los dispositivos móviles que los usuarios tienen para transmitir los datos. La combinación de estos elementos influye en la duración del tiempo de contacto entre usuarios móviles, afectando directamente a la probabilidad de entrega de información. Esta tesis comienza presentando un exhaustivo estudio del ``estado del arte", donde presentamos las contribuciones más importantes relacionadas con esta área y las soluciones existentes para la evaluación de las redes oportunísticas, tales como modelos de simulación, protocolos de enrutamiento, herramientas de simulación, entre otros. Tras ofrecer esta amplia compilación de investigaciones, se evalúa el consumo de recursos de los dispositivos móviles que afectan al rendimiento de las aplicaciones de redes oportunísticas, desde el punto de vista energético así como de la memoria. A continuación, analizamos el rendimiento de las redes oportunísticas considerando tanto los entornos peatonales como vehiculares. Los enfoques estudiados incluyen el uso de nodos fijos adicionales y diferentes tecnologías de transmisión de datos, para mejorar la duración del contacto entre dispositivos móviles. Finalmente, proponemos un esquema de difusión para mejorar el rendimiento de la transmisión de datos basado en la extensión de la duración del tiempo de contacto, y de la probabilidad de que los usuarios colaboren en este proceso. Este enfoque se complementa con la gestión eficiente de los recursos de los dispositivos móviles. / La transmissió de dades s'ha convertit en una necessitat en diversos àmbits, com ara en les xarxes socials amb les diverses aplicacions d'interacció, o en les àrees científiques i d'enginyeria, en les quals, per exemple, l'ús de sensors per a capturar dades creix en l'actualitat, o en situacions d'emergència en què impera la necessitat de tenir un sistema de comunicació per a coordinar les operacions de rescat. Les xarxes sense fil han sigut capaces de resoldre aquests problemes en gran manera, però què podem fer quan una infraestructura de suport fixa no està disponible, o bé aquestes es tornen inoperants a causa de la saturació de peticions de xarxa? Les xarxes sense fil oportunistes són una alternativa que cal considerar en aquestes situacions, ja que el funcionament d'aquestes xarxes no depèn de l'existència d'una infraestructura de telecomunicacions, sinó que la connectivitat s'hi aconsegueix a través de la cooperació organitzada dels usuaris. Aquesta tesi de recerca se centra en aquest tipus de xarxes, i té com a objectiu millorar la difusió d'informació en xarxes oportunistes tot analitzant les principals causes que influeixen en el rendiment de la transmissió de dades. Les xarxes oportunistes no depenen d'una topologia fixa, sinó del nombre i la mobilitat dels usuaris, del tipus i la quantitat d'informació generada i enviada, i de les característiques físiques dels dispositius mòbils que els usuaris tenen per a transmetre les dades. La combinació d'aquests elements influeix en la durada del temps de contacte entre usuaris mòbils, i afecta directament la probabilitat de lliurament d'informació. Aquesta tesi comença amb un estudi exhaustiu de l'estat de la qüestió, en què presentem les contribucions més importants relacionades amb aquesta àrea i les solucions oferides per a l'avaluació de les xarxes oportunistes, com ara models de simulació, protocols d'encaminament o eines de simulació, entre d'altres. Després de mostrar aquest ampli panorama, s'avalua el consum dels recursos dels dispositius mòbils que afecten l'acompliment de les aplicacions de xarxes oportunistes, tant des del punt de vista energètic com de la memòria. A continuació, analitzem l'acompliment de xarxes oportunistes considerant tant els entorns de vianants com els vehiculars. Els enfocaments estudiats inclouen l'ús de nodes fixos addicionals i diferents tecnologies de transmissió de dades per a millorar la durada del contacte entre dispositius mòbils. Finalment, proposem un esquema de difusió per a millorar el rendiment de la transmissió de dades basat en l'extensió de la durada del temps de contacte, i de la probabilitat que els usuaris col·laboren en aquest procés. Aquest enfocament es complementa amb la gestió eficient dels recursos dels dispositius mòbils. / Herrera Tapia, J. (2017). Improving Message Dissemination in Opportunistic Networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86129 / TESIS

Chronic granulomatous disease (CGD) is associated with defective function of the NADPH-oxidase system in conjunction with phagocytic defects which leads to granuloma formation and serious infectious complications. This is often associated with significant morbidity and mortality. The association of defective phagocyte function with other coincidental immune defects is unknown. Defects in innate pathways seen with CGD, including complement systems, and toll-like and dectin receptor pathways, have not been described before. We present the case of a 2-year old male patient hospitalized with recurrent pneumonia, a non-healing skin ulcer, necrotizing lung granulomas, and epididymo-orchitis. Defective neutrophil chemiluminescence was detected by dihydrorhodamine (DHR) testing. Further evaluation demonstrated characteristic molecular mutations of CYBB consistent with CGD. Immune evaluation demonstrated polyclonal hyperglobulinemia, but a greatly reduced mannose binding lectin (MBL) level. Six biallelic polymorphisms in MBL gene and its promoter were analyzed using Light Cycler™ Real-time PCR assay. The LXPA/LYPB haplotype of MBL was detected in our patient; the latter is the defective haplotype associated with low MBL levels. Due to the implications for innate immunity and the protection against bacterial, viral, and fungal infections provided by MBL, a deficiency of this protein may have disastrous consequences on the long term outcomes of CGD. MBL deficiency can also complicate other disorders affecting the immune system, significantly increasing the risk of infection in such patients. Further studies looking at the frequency and implications of MBL deficiency in CGD are needed. © 2012 Bentham Science Publishers.

Microbial interactions represent an understudied facet of human health and disease. In this study, the interactions that occur between Chlamydia trachomatis and the opportunistic fungal pathogen, Candida albicans were investigated. Candida albicans is a common component of the oral and vaginal microbiota responsible for thrush and vaginal yeast infections. Normally, Candida exist in the body as yeast. However, disruptions to the microbiota create conditions that allow expanded growth of Candida, conversion to the hyphal form, and tissue invasion. Previous studies have shown that a myriad of outcomes can occur when Candida albicans interacts with pathogenic bacteria. To determine if C. trachomatis physically interacts with C. albicans, we incubated chlamydial elementary bodies (EB) in medium alone or with C. albicans yeast or hyphal forms for 1 h. Following incubation, the samples were formaldehyde-fixed and processed for immunofluorescence assays using anti-chlamydial MOMP or anti- chlamydial LPS antibodies. Replicate samples were replenished with culture medium and incubated at 35°C for 0-120 h prior to fixation for immunofluorescence analysis or collection for EB infectivity assays. Data from this study indicates that both C. trachomatis serovar E and C. muridarum EB bind to C. albicans yeast and hyphal forms. This interaction was not blocked by pre-incubation of EB with the Candida cell wall components, mannan or β-glucans, suggesting that EB interact with a Candida cell wall protein or other structure. Bound EB remained attached to C. albicans for a minimum of 5 days (120 h). Infectivity assays demonstrated that EB bound to C. albicans are infectious immediately following binding (0h). However, once bound to C. albicans, EB infectivity decreased at a faster rate than EB in medium alone. At 6h post binding, 40% of EB incubated in medium alone remained infectious compared to only 16% of EB bound to C. albicans. Likewise, pre-incubation of EB with laminarin, a soluble preparation of β-glucan, alone or in combination with other fungal cell wall components significantly decreases chlamydial infectivity in HeLa cells. These data indicate that interactions between EB and C. albicans inhibit chlamydial infectivity, possibly by physically blocking EB interactions with host cell receptors.

When patients develop new-onset infections after hospital admission, the origin of the infection is typically assumed to be nosocomial; however, ambulances are potentially unexplored reservoirs for emerging pathogens. This study seeks to identify the scope of bacterial contamination in rural East Tennessee ambulances. Though universal precautions and cleaning procedures aim to reduce the spread of infectious diseases to provider and patient, little is known about the bacterial microbiome of ambulances. To the best of our knowledge, this is the first study of its kind to be performed in the state of Tennessee and the first since the introduction of UVGI units as an ambulance-based COVID-19 infection control measure. Our dissemination of post-pandemic findings may impact ambulance sanitation measures and will add to the national and global knowledge pertaining to the microbiome of emergency medical patient transport systems. Ambulances in East Tennessee were sampled using environmental sampling contact plates. At least one active ambulance unit for each EMS service underwent sampling. Three samples were obtained from each of three areas: the floor of the ambulance transport area, the rear door panel inside the transport area and stretcher. The plates were then incubated at 30-35C for 48 hours. Colony counts were manually performed before the plates were shipped for species identification via MALDI-TOF DNA analysis by MIDI laboratories (Newark, DE). One plate from each ambulance door and stretcher was sent for bacterial identification. Only one sample returned free of growth. All floor samples, several stretcher samples, and three door samples presented vast growth with colonies too numerous to count. The results from bacterial identification showed all flora were human commensal flora or environmental flora. The flora found on ambulance doors with opportunistic capabilities are as follows: Staphylococcus hominis, Staphylococcus epidermidis, Enterobacter cloacae, Enterobacter xinagfangensis, Bacillus cereus, Klebsiella oxytoca, and Bacillus subtilis; and the flora found on the stretchers with opportunistic capabilities are as follows: Staphylococcus haemolyticus, Staphylococcus epidermidis, Staphylococcus cohnii ssp urealyticus, Bacillus cereus, Corynebaccterium mucifaciens, Staphylococcus pettenkoferi, Klebsiella oxytoca, Staphylococcus capitis, Bacillus subtillis, and Staphylococcus caprae. In this era of increasing antibiotic resistance, it is concerning that several microbes with pathogenicity were found, including species that often confer the spread of resistance such as Klebsiella oxytoca and Enterobacter cloacae. Overall, the finding of numerous diverse colonies does not support adequate sanitation of the ambulances. Further study is required to identify the most effective sanitation methods, and further metagenomic study is needed to explore the presence of genes that facilitate the spread of microbial resistance.

Les réseaux opportunistes (DTN) permettent d'utiliser de nouveaux vecteurs de transmissions. Avant de pouvoir profiter de toutes les capacités des DTN, nous devons nous pencher sur la compréhension de ce nouveau paradigme. De nombreuses propriétés des réseaux DTN sont maintenant reconnues, cependant les relations entre un noeud du réseau et son voisinage proche ne semblent pas encore avoir été passée au crible. Souvent, la présence de noeuds voisins proches mais pas directement lié par le contact est ignorée. Dans cette thèse, nous montrons à quel point considérer les noeuds à proximité nous aide à améliorer les performances DTNs.En identifiant le paradoxe binaire dans les DTN, nous montrons que les caractérisations actuelles ne sont pas suffisantes pour bénéficier de toutes les possibilités de transmission dans les DTN. Nous proposons une définition formelle du voisinage pour les DTNs avec le ``k-vicinity''. Nous étudions les caractérisations temporelles du k-vicinity avec différentes données. Ensuite, nous nous concentrons sur l'étude de l'organisation interne du k-vicinity. Nous avons crée le Vicinity Motion qui permet d'obtenir un modèle markovien à partir de n'importe quelle trace de contact. Nous en extrayions trois mouvements principaux: la naissance, la mort et les mouvements séquentiels. Grâce aux valeurs du Vicinity Motion, nous avons pu créer un générateur synthétique de mouvements de proximité nommé TiGeR. Enfin, nous posons la question de la prévisibilité des distances entre deux noeuds du k-vicinity. En utilisant le savoir emmagasiné dans le Vicinity Motion, nous mettons au point une heuristique permettant de prédire les futures distances entre deux noeuds. / The networking paradigm uses new information vectors consisting of human carried devices is known as disruption-tolerant networks (DTN) or opportunistic networks. We identify the binary assertion issue in DTN. We notice how most DTNs mainly analyze nodes that are in contact. So all nodes that are not in contact are in intercontact. Nevertheless, when two nodes are not in contact, this does not mean that they are topologically far away from one another. We propose a formal definition of vicinities in DTNs and study the new resulting contact/intercontact temporal characterization. Then, we examine the internal organization of vicinities using the Vicinity Motion framework. We highlight movement types such as birth, death, and sequential moves. We analyze a number of their characteristics and extract vicinity usage directions for mobile networks. Based on the vicinity motion outputs and extracted directions, we build the TiGeR that simulates how pairs of nodes interact within their vicinities. Finally, we inquire about the possibilities of vicinity movement prediction in opportunistic networks. We expose a Vicinity Motion-based heuristic for pairwise shortest distance forecasting. We use two Vicinity Motion variants called AVM and SVM to collect vicinity information. We find that both heuristics perform quite well with performances up to 99% for SVM and around 40% for AVM.

Indiana University-Purdue University Indianapolis (IUPUI) / The Gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen which readily establishes itself in the lungs of people with cystic fibrosis (CF). Most CF patients have life-long P. aeruginosa infections. By modulating its own virulence and forming biofilms, P. aeruginosa is able to evade both host immune responses and antibiotic treatments. Previous studies have shown that the magnesium transporter MgtE plays a role in virulence modulation by inhibiting transcription of the type III secretion system, a mechanism by which bacteria inject toxins directly into the eukaryotic host cell. MgtE had already been identified as a magnesium transporter, and thus its role in regulating cytotoxicity was indicative of dual functions for this protein. This research focused on a structure-function analysis of MgtE, with the hypothesis that the magnesium transport and cytotoxicity functions could be exerted independently. Cytotoxicity assays were conducted using a co-culture model system of cystic fibrosis bronchial epithelial cells and a ∆mgtE strain of P. aeruginosa transformed with plasmids carrying wild type or mutated mgtE. Magnesium transport was assessed using the same mgtE plasmids in a Salmonella strain deficient in all magnesium transporters. Through analysis of a number of mgtE mutants, we found two constructs – a mutation in a putative magnesium binding site, and an N-terminal truncation – which demonstrated a separation of functions. We further demonstrated the uncoupling of functions by showing that different mgtE mutants vary widely in their ability to regulate cytotoxicity, whether or not they are able to transport magnesium. Overall, these results support the hypothesis of MgtE as a dual function protein and may lead to a better understanding of the mechanisms underlying P. aeruginosa virulence. By understanding virulence mechanisms, we may be able to develop treatments to reduce infections and pave the way to better health for people with cystic fibrosis.