No description available.

Crack formation in concrete structures due to various load and non-load factors leading to degradation of service life is very common. Repair and maintenance operations are, therefore, necessary to prevent cracks propagating and reducing the service life of the structures. Accessibility to affected areas can, however, be difficult and the reconstruction and maintenance of concrete buildings are expensive in labor and capital. Autonomous healing by encapsulated bacteria-based self-healing agents is a possible solution. In this study, a novel bacteria-based healing agent was investigated in order to test the self-healing efficiency of the specimens in comparison to the commonly used healing agents made of lactic acid derivatives. (PLA). The novel integrated healing agent is a non-toxic, biodegradable dissolved inorganic carbon substrate derived from wastewater that has been used as an encapsulation material for spores of cohnii bacteria in the Bacillus gene family and for nutrients made up of yeast extract. This dissolved inorganic carbon substrate is a bioplastic made by the bacteria in wastewater known as alkanoate derivatives (AKD). To assess the effect of these healing agents on the mortar characteristics, quantification and characterization of the self-healing were conducted. The quantification of the self-healing efficiency was performed by various experimental techniques such as light microscopy, water permeability, chloride ion permeability, and thermogravimetric analysis whereas the material characterization was investigated by x-ray diffraction and environmental scanning electron microscope. Moreover, a statistical analysis was performed to study the correlation of self-healing efficiency between various experimental techniques. The incorporated dosages of healing agents adopted were 2.6% and 5% by weight of cement. Complete immersion in water was considered to be the condition of treatment of the specimen for healing at two separate periods of 28 and 56 days. The crack widths investigated were in the range of 0.04 to 0.8 mm. The quantification and characterization tests indicated that bacterial containing mortar series especially PLA and AKD at 5% dosage displayed a higher self-healing performance and an indication of precipitated calcium carbonate in the crack mouth. However, the results from the chloride migration test didn’t show any influence by the self-healing healing agents. Furthermore, the statistical analysis identified a major impact of the internal crack geometry on the difference in self-healing ratios, also in the cases where effective crack width is equal. / Sprickbildning i betongkonstruktioner p.g.a. olika laster och lastoberoende faktorer som leder till förkortning av livslängden är mycket vanligt förekommande. Reparation och underhåll är därför nödvändiga för att förhindra att sprickorna propagerar och reduceras konstruktionernas livslängd. Möjligheterna att komma åt de skadade partierna kan dock vara svåra och reparationerna är vanligen både arbetsintensiva och kostsamma. Självläkning med ingjutna bakteriebaserade, självläkande tillsatser är en möjlig lösning på problemet. I denna studie undersöktes en ny bakteriebaserat självläkande tillsats för att prova den självläkande förmågan i jämförelse med vanligt förekommande självläkande tillsatser av mjölksyrederivat (PLA). Den nya integrerade självläkande tillsatsen är en giftfri, biologiskt nedbrytningsbar, oorganisk kolsubstratslösning utvunnen ur avloppsvatten, en tillsats som har använts som ett inkapslingsmaterial för sporer från cohnii-bakterier från bacillussläktet och från näringsämnen framställda ur jästextrakt. Denna kolsubstratslösning är en bioplast framställd ur avloppsvatten och känd som alkanoatderivat (AKD). För att bestämma effekten av dessa självläkande tillsatser på cement bruks egenskaper genomfördes kvantifiering och karakterisering av självläkningen. Kvantifieringen av självläkningens effektivitet utfördes genom olika experimentella metoder såsom ljusmikroskopi, vattengenomsläpplighet, kloridjonstransport och termogravimetriska analyser medan materialkarakteriseringen utfördes med röntgendiffraktion och svepelektronmikroskop (ESEM). Vidare genomfördes en statistisk analys för att undersöka korrelationen mellan olika experimentella metoder. De doser av självläkande tillsatser som användes var 2,6 och 5 % av cementvikten. Fullständig nedsänkning i vatten ansågs vara den lämpligaste lagringen för självläkning under två olika tidsperioder på 28 respektive 56 dygn. De sprickbredder som studerades låg i intervallet 0.04 till 0.8 mm. Försöken kring kvantifiering och karakterisering indikerade att bruken innehållande bakterier, i synnerhet 5 % PLA och AKD, utvecklade en högre form av självläkande beteende och en förekomst av kalciumkarbonat i sprickspetsen. Resultaten från försöken kring kloridtransport visade emellertid inga tecken på någon effekt från de självläkande tillsatserna. Vidare identifierades i den statistiska analysen att inre sprickbildning har stor betydelse för självläkningseffekten även i fall där den effektiva sprickbredden är lika stor.

Capillary electrophoresis mass spectrometry (CE-MS) is a versatile instrumental method for metabolomics, which allows for comprehensive metabolite profiling of volume-limited biological specimens in order to better understand the molecular mechanisms associated with chronic diseases, including an alarming epidemic of obesity worldwide. Multiplexed CE separations enable high-throughput metabolite screening with quality assurance to prevent false discoveries when combined with rigorous method validation, robust experimental designs, complementary statistical methods, and high-resolution tandem mass spectrometry (MS/MS) for unknown metabolite identification. In this thesis, multiplexed CE-MS technology is applied for both targeted and untargeted metabolite profiling of various biological fluids, including covalently bound thiol-protein conjugates, as well as free circulating metabolites in serum and plasma, and excreted/bio-transformed compounds in urine due to complex host-gut microflora co-metabolism. This work was applied to characterize aberrant metabolic responses of obese subjects in response to dietary challenges, and measure the benefits of dietary interventions that reduce adiposity without deleterious muscle loss. Chapter 2 presents, a simple, sensitive yet robust analytical protocol to expand metabolome coverage in CE-MS for the discovery of labile protein thiols in human plasma using a rapid chemical derivatization method based on N-tert-butylmaleimide (NTBM). Chapter 3 describes targeted metabolite profiling of serum and plasma to investigate the differential metabolic responses between healthy and unhealthy obese individuals before and after consumption of a standardized high-caloric meal, respectively. Chapter 4 of this thesis describes an untargeted metabolite profiling strategy for urine using multisegment-injection (MSI)-CE-MS for elucidating the effects of protein supplementation following a short-term dietary weight-loss intervention study. This work revealed six urinary metabolites that were classified as top-ranking treatment response biomarkers useful for discriminating between subjects consuming carbohydrate (control), soy, and whey supplemented diets. In summary, this thesis demonstrated the successful implementation of multiplexed CE-MS technology for biomarker discovery in nutritional-based metabolomic studies as required for more effective treatment and prevention of obesity for innovations in public health. / Thesis / Doctor of Philosophy (PhD)

The distributions of soil mechanical parameters required for a comprehensive flood risk assessment are often taken from the scarce literature available. This article therefore presents a method to indirectly obtain the distributions from the results of often conducted classification tests. Empirical correlation terms are used for the transformation of the classification data into stability-relevant parameters, in particular the void ratio, the soil unit weight, the friction angle and the saturated permeability. The method is applied exemplarily to a data set collected throughout Germany in the immediate vicinity of water bodies and plausible distributions are obtained for 2/3 of the 13 soil classes considered. For the validation of the results, the extension of (inter)national databases by samples of the considered soil mechanical parameters is recommended due to the current poor validation basis.

La présente thèse de doctorat porte sur la relation entre la perception de la justice organisationnelle, l’émission de comportements inadaptés au travail et la santé psychologique des individus au travail. En plus de développer un outil de mesure des comportements inadaptés au travail et d’entreprendre un processus de validation de celui-ci, le présent travail propose que les comportements inadaptés au travail puissent occuper un rôle soit protecteur ou explicatif dans la relation qui unit la perception de la justice organisationnelle avec la santé psychologique des individus au travail. Au sein de cette thèse, le premier article recense la documentation scientifique quant aux variables de la perception de la justice organisationnelle, de l’émission des comportements inadaptés au travail et de la santé psychologique des individus au travail, ainsi que les liens qui unissent ces variables. Aussi, les modèles conceptuels des rôles modérateur et médiateur des comportements inadaptés au travail sont proposés au sein de la relation entre la perception de la justice organisationnelle et la santé psychologique des individus au travail. Le deuxième article a pour objectif de développer un outil de mesure des comportements inadaptés au travail et de tester ses propriétés psychométriques. Ainsi, des analyses statistiques exploratoires et confirmatoires ont été effectuées. Afin d’appuyer la valeur critériée de l’outil proposé, une analyse corrélationnelle a été réalisée avec le critère de l’adaptation. Certaines valeurs psychométriques de l’outil sont validées par les résultats obtenus. Le troisième article examine empiriquement les modèles conceptuels des rôles anticipés des comportements inadaptés au travail dans la relation entre la perception de la justice organisationnelle et la santé psychologique des individus au travail. La perception de la justice organisationnelle a été vue sous les composantes distributive, procédurale, informationnelle et interpersonnelle. De son côté, la santé psychologique des individus a été observée par le biais des éléments du bien-être et de la détresse psychologique au travail. Les différentes analyses de régressions multiples hiérarchiques ont permis d’observer l’absence du rôle modérateur des comportements inadaptés au travail. Pour sa part, l’utilisation du test de Sobel a démontré la présence du rôle médiateur des comportements inadaptés au travail dans certaines relations. Plus exactement, celles-ci sont la relation entre la justice interpersonnelle et le bien-être psychologique au travail, la relation entre la justice interpersonnelle et la détresse psychologique au travail, ainsi que la relation entre la justice distributive et la détresse psychologique au travail. Finalement, la conclusion de la thèse présente une synthèse des résultats et expose les limites et pistes de recherches futures. / The present doctoral thesis treats of the relation between perception of organizational justice, emission of misbehaviours at work, and individuals’ psychological health at work. In addition to developing and undertaking a validation process for a measuring scale of misbehaviours at work, the present thesis proposes that these behaviours may occupy either a protective or an explicative role in the relationship that unites the perception of organizational justice with individuals’ psychological health at work. Within the thesis, the first article lists scientific literature concerning the perception of organizational justice, the emission of misbehaviours at work, and individuals’ psychological health at work. This article also includes a revue of links that unite the variables presently at study. Following this review, two conceptual models about possible roles played by misbehaviours at work in the relationship between perception of organizational justice and individuals’ psychological health at work are developed. More precisely, these models are conceptualisation of the moderating and mediating roles of inadequate work behaviours. The second article’s goal is the development of a measuring scale for misbehaviours at work and testing its psychometric proprieties. In this context, exploratory and confirmatory statistical analyses were made. Also, in order to support the criterion value of the proposed tool, a correlation analysis was made with the criteria of adaptation. The results showed that certain psychometric values were validated. The third article empirically examines the conceptual models developed about the possible roles played by misbehaviours at work in the relationship between perception of organizational justice and individuals’ psychological health at work. Organisational justice perception was analysed under distributive, procedural, informational and interpersonal components. As for individuals’ psychological health at work, it was observed through the psychological well-being and distress elements. The different multiple hierarchical regression analyses helped observe the absence of a moderator role for misbehaviours at work. Using the Sobel test showed the presence of a mediator role for misbehaviours at work in the relationship between the interpersonal organizational justice component and well-being, as well as psychological distress at work. This same test highlighted the mediator role of misbehaviours at work in the relationship between the distributive component of organizational justice and the psychological distress at work of individuals. Finally, the conclusion of this thesis presents a synthesis of the results and highlights the limits and future research ideas.

This study investigated whether girls achieve better results in Physical Science in single sex environments or in co-educational classes. Thirteen independent South African schools where children were of similar socio-economic background were considered. Grade 12 Matriculation Physical Science examination results for 1999 to 2003 were analysed using Bonferroni (Dunn) t-Tests and Scheffe's Tests. Questionnaires were completed by a small number of students in order to compare their attitudes towards Physical Science and examined qualitatively. There were significant differences found by the administration of the Bonferroni (Dunn) t-Tests and Scheffe's Tests in 2000, 2001 and 2002 to indicate that girls in single sex schools achieved better results in Science than the co-educational schools. However, in 1999 and 2003 there was no significant difference in the results achieved, and so there may be other factors that are more important predictors of achievement than whether the schools are mixed or single sex. / Educational Studies / M.Ed. (Natural Science Teaching)

Juniper trees (Juniperus osteosperma, J. monosperma, J. deppeana and J. scopulorum) grow under widely varying climatic and edaphic conditions throughout the American southwest. This study is chiefly concerned with a test of the climatic response in the partitioning of the stable isotopes of carbon in such trees. The relationships developed here, for example, might be used to extract paleoclimatic information from ancient juniper samples preserved in cave middens. In order to test for a climatic response in the leaf cellulose δ¹³C values, leaves from a total of 29 trees were sampled in the immediate vicinity of 9 meteorological stations across the state of Arizona. Care was taken to insure that 22 of the trees experienced only the temperature and precipitation values reflected by their site meteorological stations. As a cross-check, 7 trees exposed to temperature and/or precipitation levels clearly deviant from their site averages were also sampled. In general, each tree was sampled at four places, approximately 2 m above the ground. All leaf samples were reduced to cellulose (holocellulose) before combustion and analysis for their δ¹³C value. The δ¹³C value for each site was derived from an average of 2 to 4 trees per site, the value of each tree being the average of its individual samples. The one sigma 13C variation found between trees at any given site is ±0.38‰; within a single tree, ±0.36‰; and for repeat combustions, ±0.20‰. The δ¹³C values of the juniper sites were regressed against the temperature and precipitation of the individual months and running averages of months across the year using polynomial, multiple regression analysis. Temperature and precipitation were entered as separate variables in a general multiple regression model and also as a combined, single variable (T /P) in a more specific approach. The pattern formed by the multiple correlation coefficients, when plotted by months across the year, closely follows the seasonal variations in photosynthetic activity. Cellulose δ¹³C values have minimum correlation with temperature and precipitation (considered jointly) during summer months and maximum correlation during spring months. For an individual month, the temperature and precipitation (jointly) of April correlated at the highest level with a multiple adj. R = 0.994 and an F = 166; for a maximum seasonal response, March-May reached a multiple adj. R = 0.985, F = 66. The results using the combined, single variable (T /P) were nearly equivalent for the same months: April's adj. R = 0.957, F = 45; March-May's adj. R = 0.985 with an F = 132. The ability of T and P as independent predictors is considerably less than their ability in combination; e.g., 13C g(T) for March-May has an adj. R = 0.80 and 6 13C = h(P) has an adj. R = -0.67 compared to their in- concert adj. R value of 0.985. The results of this study, therefore, strongly support a high degree of climatic sensitivity in the partitioning of the stable isotopes of carbon in juniper leaf cellulose: the correlation coefficients and their F statistics are sufficiently high to consider temperature and precipitation (acting jointly) as accurate predictors of cellulose δ¹³C values in the system studied.

No description available.

A lesão do plexo braquial é considerada a alteração neural mais grave das extremidades. A principal causa é o trauma de alta energia, especialmente acidentes envolvendo veículos a motor. Por este motivo, as lesões traumáticas do plexo braquial são cada vez mais frequentes. O presente estudo avaliou a acurácia da ressonância magnética (RM) no diagnóstico das lesões traumáticas do plexo braquial no adulto, utilizando o achado intraoperatório como padrão-ouro. Também foi avaliada a acurácia da neurografia pesada em difusão (neurografia DW) em relação à RM convencional e a capacidade de diferenciação dos três tipos de lesão: avulsão, ruptura e lesão em continuidade. Trinta e três pacientes com história e diagnóstico clínico de lesão traumática do plexo braquial foram prospectivamente estudados por RM. Os achados obtidos pela RM sem e com o uso da neurografia DW, e os achados de exame clínico foram comparados com os achados intraoperatórios. A análise estatística foi feita com associação de significância de 5%. Observou-se alta correlação entre a RM com neurografia DW e a cirurgia (rs=0,79), e baixa correlação entre a RM convencional e a cirurgia (rs=0,41). A correlação interobservador foi maior para a RM com neurografia DW (rs = 0,94) do que para a RM sem neurografia DW (rs = 0,75). Os resultados de sensibilidade, acurácia e valor preditivo positivo foram acima de 95% para as RM com e sem neurografia DW no estudo de todo o plexo. As especificidades foram, em geral, maiores para a neurografia DW (p < 0,05). Em relação à diferenciação dos tipos de lesão, a RM com neurografia DW apresentou altas acurácias e sensibilidades no diagnóstico da avulsão/rotura, e alta especificidade no diagnóstico da lesão em continuidade. A acurácia da RM (93,9%) foi significativamente maior que a do exame clínico (76,5%) no diagnóstico das lesões de todo o plexo braquial (p < 0,05). / Brachial plexus injury is considered the most severe neural disorder in the extremities and in general resulting from high-energy trauma in young patients, usually involving motor vehicles. For this reason, traumatic brachial plexus injuries are becoming more frequent. This study evaluated the accuracy of magnetic resonance imaging (MRI) in the diagnosis of traumatic brachial plexus injuries in adults, using surgical findings as the gold standard method. We also evaluated the accuracy of diffusion weighted image neurography (DW neurography) compared to conventional MRI and the ability to differentiate the three types of injuries by MRI: avulsion, rupture and lesion-in-continuity. Thirty-three patients with clinical history and diagnosis of traumatic brachial plexus injury were prospectively studied by MRI. MRI findings (obtained with and without use of DW neurography) and clinical examination were compared with intraoperative findings. The statistical analysis was performed with 5% significance association. There was high correlation between MRI with DW neurography and surgery (rs = 0.79) and low correlation between conventional MRI and surgery (rs = 0.41). The interobserver correlation was higher for MRI with DW neurography (rs = 0.94) than for regular MRI (rs = 0.75). The sensitivities, accuracies and positive predictive values were above 95% for MRI (with and without DW neurography) in the evaluation of the entire plexus. The specificities were generally higher for DW neurography (p < 0.05). Regarding the differentiation between types of lesions, MRI with DW neurography demonstrated high accuracies and sensitivities in the diagnosis of avulsion / rupture and high specificity in the diagnosis of lesion-in-continuity. MRI accuracy (93.9%) was significantly higher than clinical examination (76.5%) in diagnosis of brachial plexus traumatic lesions (p < 0.05).

Amphibians globally are declining with roughly a third facing extinction due primarily to threats linked to human impacts. One way in which this is being combated is by captive breeding programs. Nordens Ark in Sweden, in collaboration with other organizations, is attempting to breed one of the most threatened frogs for future reintroduction to the wild. The mountain chicken (Leptodactylus fallax) has unique characteristics related to its reproduction which make it challenging to breed successful offspring. Using Nordens Ark’s data on environmental conditions within breeding enclosures, this study attempts to determine which extrinsic factors are having the most influence on reproduction, in order to increase the success of the captive breeding program. Multiple linear regression analysis and model simplification using Stepwise regression and Akaike information criterion (AIC) were performed in order to determine which explanatory variables had the most influence in relation to foam nests. A reduced model with significant values for explanatory variables was deemed the best model based on the dataset. Of the 14 environmental variables tested, minimum temperature after nest construction had the most influence on foam nest length. When compared to wild habitats, temperatures within enclosures may be too high or lack seasonal cyclical patterns. Barometric pressure and humidity also had influence on foam nests, but the relationships between these environmental conditions is difficult to parse. Food supplements were also a significant factor and suggest that lack of vitamins or nutrients can have a negative effect on reproductive success. Ensuring the optimal conditions can be difficult for captive breeding programs, especially as amphibians are under-represented and face biases in conservation and research.