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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Interakce viru klíšťové encefalitidy s cytoskeletem hostitelských buněk

PRANČLOVÁ, Veronika January 2019 (has links)
This thesis is focused on the role of host cytoskeleton, primarily microtubules and microfilaments, during tick-borne encephalitis virus infection in human neuroblastoma cell line SK-N-SH and tick cell line IRE/CTVM19. The importance of cytoskeletal integrity and dynamics to the viral replication cycle were examined using specific chemical inhibitors showing the virus utilizes studied structures in both cell lines. Immunofluorescence microscopy revealed structural changes in the actin cytoskeleton during late infection in SK-N-SH cells. Moreover, differences in expression of cytoskeleton-associated genes in both cell lines were compared. Several genes with up-regulated expression in SK-N-SH cells were identified during late infection.
102

Développements d'indicateurs de qualité dans la modélisation des ouvrages géotechniques par la méthode des éléments finis : applications aux soutènements

Vulpe, Cristina 07 September 2011 (has links) (PDF)
Notre thèse propose d'étudier la précision des calculs par la méthode des éléments finis (MEF) au moyen "d'indicateurs de qualité". Les indicateurs de qualité représentent des formules simples qui permettent d'évaluer la qualité des calculs par éléments finis. La qualité de l'analyse numérique est évaluée par rapport à la discrétisation. Le modèle mathématique est considéré correct et les erreurs résultant du choix des propriétés des matériaux ne sont pas pris en compte. Nous avons défini les formulations mathématiques de ces indicateurs de qualité, ainsi que leurs limites inférieures et supérieures. Grâce au choix de formulations simples, il est facile de les introduire dans un logiciel de calcul par éléments finis. Ils ont été implémentés dans le code de calcul CESAR-LCPC, module Mécanique en Comportement Non Linéaire. Afin de démontrer qu'ils ont été correctement définis et de tester leur fiabilité, ces indicateurs de qualité sont testés sur un certain nombre de problèmes simples en 2D et en 3D. Après avoir prouvé leur capacité à caractériser la qualité de la discrétisation des modèles d'éléments finis, nous les avons testés sur le cas d'une excavation de palplanches butonnées (site expérimental de Hochstetten, près de Karlsruhe). La précision des résultats en termes de propriétés mécaniques choisies pour le sol et les structures n'a pas été étudiée. Nous avons également démontré que les résultats sont indépendants des propriétés mécaniques choisies pour le sol ou la structure
103

Spatial Distribution of Tick-Borne Pathogens as a Consequence of Vector-Host-Pathogen Interactions with Environment / Spatial Distribution of Tick-Borne Pathogens as a Consequence of Vector-Host-Pathogen Interactions with Environment

HÖNIG, Václav January 2015 (has links)
The proposed thesis contributes to the basic knowledge in tick (Ixodes ricinus) and tick-borne pathogens (Borrelia burgdorferi sensu lato, tick-borne encephalitis virus) ecology in particular studying the spatial distribution, host associations and its causes and consequences in Central European habitats.
104

Développements d’indicateurs de qualité dans la modélisation des ouvrages géotechniques par la méthode des éléments finis : applications aux soutènements / Development of quality indicators for the finite element method : application to retaining structures

Vulpe, Cristina 07 September 2011 (has links)
Notre thèse propose d'étudier la précision des calculs par la méthode des éléments finis (MEF) au moyen "d'indicateurs de qualité". Les indicateurs de qualité représentent des formules simples qui permettent d'évaluer la qualité des calculs par éléments finis. La qualité de l'analyse numérique est évaluée par rapport à la discrétisation. Le modèle mathématique est considéré correct et les erreurs résultant du choix des propriétés des matériaux ne sont pas pris en compte. Nous avons défini les formulations mathématiques de ces indicateurs de qualité, ainsi que leurs limites inférieures et supérieures. Grâce au choix de formulations simples, il est facile de les introduire dans un logiciel de calcul par éléments finis. Ils ont été implémentés dans le code de calcul CESAR-LCPC, module Mécanique en Comportement Non Linéaire. Afin de démontrer qu'ils ont été correctement définis et de tester leur fiabilité, ces indicateurs de qualité sont testés sur un certain nombre de problèmes simples en 2D et en 3D. Après avoir prouvé leur capacité à caractériser la qualité de la discrétisation des modèles d'éléments finis, nous les avons testés sur le cas d'une excavation de palplanches butonnées (site expérimental de Hochstetten, près de Karlsruhe). La précision des résultats en termes de propriétés mécaniques choisies pour le sol et les structures n'a pas été étudiée. Nous avons également démontré que les résultats sont indépendants des propriétés mécaniques choisies pour le sol ou la structure / The thesis proposes to study the accuracy of the finite element method (FEM) analyses by means of « quality indicators ». The quality indicators represent simple mathematical formulas that are designed to evaluate the reliability of the numerical analyses. The accuracy of the discretization modeling of these analyses is determined ; the mathematical model is considered correct and the errors resulting from the choice of the mechanical properties of the soil are not taken into account. We proposed the mathematical formulations of the quality indicators and also established their lower and upper bounds. Due to their simple mathematical formulation, the quality indicators are easily implemented in any finite element computer code. We have introduced them in the CESAR-LCPC finite element computer code, namely in the nonlinear mechanical execution module. The proposed quality indicators are used on a number of simple 2D and 3D problems elastic and elastoplastic problems in order to assess the jump in stress values in the nodes of the generated mesh. After testing the accuracy of the discretization modeling of these numerical analyses, we evaluated the discretization modeling quality of a braced sheetpile excavation (Hochstetten experimental site, near Karlsruhe). The accuracy of the results based on the mechanical properties of the soil and the structure has not been studied. Also, we proved that the quality indicator results are independent of the chosen mechanical properties for the soil or structure
105

Lines of Site

Mingo, Ryan J. 10 March 1998 (has links)
Architecture in today's urban environments exists through, and must respond to, the interaction of contemporary constructs occurring within the context of the urban fabric of the established city. The opportunity residing between these concurrent systems of past and present offers the flexibility of countless modes of response to the ever-changing city Concerns of today"s architectural possibilities to the protection of the past, while enabling the evolution of the urban setting afford the designers of our cities a diversity of options in response to the needs and desires of modern society. Context is of primary concern, and must be addressed not only as the physical characteristics of the "site / Master of Architecture
106

Transcriptomic and proteomic analysis of arbovirus-infected tick cells

Weisheit, Sabine January 2014 (has links)
Ticks are important vectors of a wide variety of pathogens including protozoa, bacteria and viruses. Many of the viruses transmitted by ticks are of medical or veterinary importance including tick-borne encephalitis virus (TBEV) and Crimean- Congo hemorrhagic fever virus causing disease in humans, and African swine fever virus and Nairobi sheep disease virus affecting livestock. Although several studies have elucidated tick antimicrobial mechanisms including cellular immune responses such as nodulation, encapsulation and phagocytosis and humoral immune responses such as the JAK/STAT pathway, complement-like proteins, antimicrobial peptides, lectin like pattern-recognition molecules and lysozymes, very little is known about the innate immune response of ticks towards viral infection. This study therefore aimed to identify molecules that might be involved in the response of ticks to viral infection. The hypothesis was that TBEV infection leads to changes in the expression of immunity-related transcripts and proteins in Ixodes spp. tick cells and that at least some of these might be antiviral. Ixodes scapularis-derived cell lines IDE8 and ISE6 were chosen since I. scapularis is currently the only tick species with a sequenced genome and an Ixodes ricinus-derived cell line, IRE/CTVM19, was used because I. ricinus is the natural vector of TBEV. Basic parameters required to study the responses of tick cells to infection were determined, including levels of virus infection, kinetics of virus replication and production, formation of replication complexes and uptake of dsRNA or siRNA. The cell lines IDE8, ISE6 and IRE/CTVM19 were infected with either of two tick-borne flaviviruses, TBEV and Langat virus (LGTV), or with the mosquito-borne alphavirus Semliki Forest virus (SFV). Infection was characterised using techniques including plaque assay, luciferase assay, immunostaining and conventional, confocal and electron microscopy. Two time points for transcriptomics and proteomics analysis of TBEVinfected IDE8 and IRE/CTVM19 cells were selected: day 2 post-infection (p.i.) when virus production was increasing and day 6 p.i. when virus production was decreasing. RNA and protein were isolated from TBEV-infected and mock-infected tick cells at days 2 and 6 p.i. and RNA-Seq and mass spectrometric technologies were used to identify changes in, respectively, transcript and protein abundance. Differential expression of transcripts was determined using the data analysis package DESeq resulting in a total of 43 statistically significantly differentially expressed transcripts in IDE8 cells and 83 in IRE/CTVM19 cells, while differential protein representation using Χ2 test statistics with Bonferroni correction in IDEG6 software resulted in 76 differentially represented proteins in IDE8 cells and 129 in IRE/CTVM19 cells. These included transcripts and proteins which could affect stages of the virus infection, including virus entry, replication, maturation and protein trafficking, and also innate immune responses such as phagocytosis, RNA interference (RNAi), the complement system, the ubiquitin-proteasome pathway, cell stress and the endoplasmic reticulum (ER) stress response. After verification of sequencing data by qRT-PCR, the ability of several of the identified transcripts or proteins to affect virus infection was determined by knockdown experiments in IDE8 and IRE/CTVM19 cells using wild type LGTV, LGTV replicons or TBEV replicons. Knockdown of genes encoding proteins including the ER chaperone gp96 and the heat-shock protein HSP90 resulted in increased virus production in both cell lines, hinting at an antiviral role. In contrast, knockdown of calreticulin, another ER chaperone, resulted in a decrease in virus production in IRE/CTVM19 cells but not in IDE8 cells, implying a requirement for virus production. This functional genomics approach has identified possible novel genes/proteins involved in the interaction between flaviviruses and tick cells and also revealed that there might be antiviral innate immune pathways present in ticks additional to the exogenous RNAi pathway.
107

Temporal Analysis and Spatial Modeling of the Distribution and Abundance of Cs. melanura, Eastern Equine Encephalitis Vector: Connecticut, 1997-2012

White, Chelsi January 2016 (has links)
Eastern Equine Encephalitis virus is a vector-borne virus amplified by the Culiseta melanura mosquito in an enzootic avian cycle, causing high morbidity and mortality to horses and humans when contracted as incidental hosts. The virus is distributed across most of the eastern United States, Canada, and Gulf coast, and has been expanding in geographic range and season of activity over time. Spatial-temporal trends in Cs. melanura abundance were correlated with available meteorological (temperature and precipitation) and remotely sensed environmental data for the period of 1997-2012 in Connecticut. The effects of inter-annual changes in precipitation, temperature, and groundwater levels on Cs. melanura abundances using time-series linear regression and cross-correlation analyses were inconclusive. Habitat modeling using logistic regression and landscape-based predictive variables demonstrated strong efficiency (46.2%) and acceptable sensitivity and specificity (65.6 and 78.6%, respectively) using NDVI difference and distance from palustrine areas as predictive factors. Remotely sensed data can improve the understanding of vector abundance patterns, helping to forecast future outbreaks and regional expansions by guiding surveillance efforts.
108

Values in Antarctica: Discourse Analyses of Two Topical Issues in Antarctic Policy

Engelbertz, Sira January 2015 (has links)
In light of growing international awareness and interests in the ‘frozen continent’ of Antarctica, the topic of Values in Antarctica has recently gained more research interest. Due to the complexity of the concept of value, values in Antarctica have been approached from many different perspectives, including Antarctic wilderness and aesthetic values, values manifested in Antarctic law or value based behavioural changes through the Antarctic experience. The present thesis addresses values as human connections to Antarctica with a focus on Antarctic policy-making. The investigation contained three analytical stages that built on each other. The first stage has been an interdisciplinary literature review examining what values are and how values can be studied, but also considered values in the context of environment, human behaviour and policy. Value and value-related concepts were selected in view of a potential application to the Antarctic. The second analytical stage involved a general framework analysis of the Antarctic Treaty System to identify key elements and structures in the system suitable for a study of Antarctic values, and to develop the research questions. The third stage of analysis included empirical investigations of two Antarctic case studies. Key elements that influence the Antarctic Treaty System in a way that is relevant for a study of Antarctic values include external factors and events, action situations and actors participating in these action situations. Antarctic Treaty Meeting of Experts appeared as an action situation particularly suitable for a study of Antarctic values. The last two Antarctic Treaty Meeting of Experts on ship-borne tourism and climate change have been chosen as case studies, presenting two topical issues in Antarctic policy. Using discourse analysis based on documents submitted to the meetings and the meetings’ reports, values that are driving the discourses were to be identified through structures and patterns in the discourses. Further, based on the discourse analysis following three research questions were to be answered: What role is ascribed to Antarctica concerning contemporary issues? Where and why do conflicts arise in the ATS policy-making process that are based on conflicting values? What changes in the underlying belief-systems are driving policy-making processes and what has caused the change? Based on the literature, values are defined as internalised codes that affect behaviour and include judgements on what is good and desirable. Through the framework analysis it was identified that Antarctic policy involves a multi-layered system of different value systems, which was considered in the two case studies. For both case studies, values in the discourses were mostly identified based on Schwartz’s basic human value theory. The most prominent human value that drives both the ship-born tourism and the climate change discourse is security. Both discourses are further motivated by the conservation of the Antarctic environment and its associated ecosystems. Other values, such as power and conformity with rules were also clearly expressed in the discourses. With regard to the research questions, both case studies discussed Antarctica from two different perspectives, as a hazardous place for human activities and as a place vulnerable to any kind of changes. Conflicts in the ship-borne tourism discourse were more obvious, while the climate change discourse within the expert meeting proceeded in consensus. Value-based changes that are evident in changes in belief-systems underlying Antarctic policy-making could not be identified. This thesis argues, based on careful consideration of documents, that values play a crucial role in Antarctic policy-making at a number of different scales: individuals, political actors, and governmental levels. Values were found to be at the core of most, if not all, conflicts within the Antarctic system. Finally, this thesis provides the first understanding of the values held by the various stakeholders involved in governing and use of the Antarctic, which is crucial for further decision-making and research.
109

Egg and Egg Product Safety and Quality

Misner, Scottie, Whitmer, Evelyn 05 1900 (has links)
2 pp. / Revision of 1997 title by Meer and Misner / From 1988 to 1992, 66% of all food-borne illnesses caused by salmonella enteritidis involved eggs or foods containing eggs. Contamination of eggs may occur on the inside as well as the outside of the shell. This article outlines the proper refrigeration, cooking and handling methods to prevent most egg safety problems.
110

Applications of spice extracts and other hurdles to improve microbial safety and shelf-life of cooked, high fat meat products (doner kebab)

Al-Kutby, Sahar January 2012 (has links)
There is a growing demand for safe and convenient meat products. The effect of natural spice extracts incorporated with other hurdles for controlling pathogenic bacteria and extending the shelf life of RTE doner kebab were investigated. A comprehensive literature review was undertaken to establish the status of microbial risk, use of additives, knowledge on oxidative deterioration and HACCP associated with meat products. The in vitro antioxidant and antibacterial activities of spice extracts were screened and compared. Cinnamon, clove, and sumac alcoholic extracts demonstrated strong antimicrobial effect, however, rosemary proved effective as antioxidant in a lamb fat model. An accelerated shelf life study on a model system indicated that storage temperature was the most critical factor affecting lipid oxidation, which was effectively delayed by vacuum packaging and rosemary extracts. The effects of spice extracts, packaging and storage time on physiochemical, microbiological, and sensory attributes of doner kebab were evaluated. Application of rosemary and cinnamon extracts significantly reduced TVC, inhibited LAB, and retarded lipid oxidation rate. Sensory evaluation by a consumer panel indicated that only taste and spiciness perception was significantly different between treatments. A challenge test against Listeria monocytogenes showed significant differences between control and spice treatments at day 28. Strong inhibitory effects were associated to high levels of cinnamon particularly when applied after cooking. The effect of heat treatment and sumac (Rhus coriaria) on Bacillus cereus and Clostridium perfringens inactivation was evaluated on a doner kebab prototype. Addition of sumac significantly reduced D-values and z-values for both organisms in comparison to the control. The investigation of the effect of spice extracts, and environmental conditions on changes in growth kinetic parameters for L. monocytogenes and Salmonella Typhimurium showed that spice extracts are highly significant. For both microorganisms, Mumax was reduced as salt and spice concentrations increased, and pH levels decreased. This study shows that spice extracts incorporated with other hurdles can help to maintain safe and good quality RTE doner kebab.

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