L'asthme est une maladie chronique des bronches caractérisée par une inflammation de la paroi bronchique, une hyperréactivité bronchique ainsi qu'une obstruction variable. L'éosinophile contribue à la physiopathologie de l'asthme en sécrétant divers médiateurs pro-inflammatoires, notamment les cysteinyl-leucotriènes (CysLT), qui initient et perpétuent la cascade inflammatoire. Des antagonistes des récepteurs des CysLT comme le Montelukast (MTK) ont été développés afin de diminuer les symptômes associés à l'action des leucotriènes. De récentes études ont démontré que le MTK agit sur des fonctions cellulaires par des mécanismes encore inconnus. Ainsi, nous avons postulé que le MTK agissait sur certaines fonctions de l'éosinophile. Nous avons démontré que le MTK inhibe la biosynthèse de LTC4 chez l'éosinophile sanguin. Toutefois, les mécanismes d'inhibition du MTK restent à élucider. Cette étude a permis de comprendre davantage la régulation de la biosynthèse de LTC4 chez l'éosinophile sanguin.

The kinetics of base-catalyzed isomerization and hydration of butadiene sulfones has been studied by using the gas chromatographic method. The reaction has been shown to be first-order with respect to each of the three components, i.e., α-butadiene sulfone, β-butadiene sulfone, and alcohol, in this complex reaction system. It is also first-order with respect to base, and second-order overall. The rate constants and relative rate constants of this reaction system have been obtained in the range of 35 to 55° C. The thermodynamic quantities of the reversible isomerization of β-butadiene sulfone to a-butadiene sulfone have been evaluated. The heat of isomerization obtained in this investigation is consistent with an independent thermochemical measurement. / Master of Science

This thesis examines the challenge of regulation in China's dairy industry—a sector that went from being the country's fastest growing food product to the 2008 melamine-milk incident and a nationwide food safety crisis. In this pursuit, it attempts to bridge the gap between analyses that view food safety problems through the separate lenses of the state regulatory apparatus and industry governance. It offers state-business interaction as a critical and fundamental component in both of these food safety mechanisms, particularly in the case of China where certain party-state activities can operate within industry chains. Using this framework, it traces party-state involvement in the dairy value chain from the industry's initial takeoff in the late 1990s and early 2000s through the years leading up to and following the melamine-milk incident. It reveals that the realities of upstream dairy production diverged significantly from party-state and industry demands, creating space for food safety issues. At the same time, state-business interaction—particularly at the local level—limited the ability of actors to address these vulnerabilities. It constrained coordination and control between lead firms and their suppliers, between chain actors and party-state institutions and within the operations of vertically integrated enterprises. In sum, dairy's regulatory challenges stemmed from structural issues in the way that the party-state interacted with business, and not necessarily from a lack of appropriate legislation or value chain models. The thesis draws on fieldwork conducted from 2009-2010 and incorporates material from relevant government policy as well as from a set of internal documents detailing the operations of a particular Chinese dairy processor, here called “Company X,” one year prior to the melamine-milk incident.

The C3 photosynthetic pathway uses light energy to reduce CO2 to carbohydrates and other organic compounds and is a central component of biological metabolism. In C3 photosynthesis, CO2 assimilation is catalyzed by ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), which reacts with both CO2 and O2. While competitive inhibition of CO2 assimilation by oxygen is suppressed at high CO2 concentrations, O2 inhibition is substantial when CO2 concentration is low and O2 concentration is high; this inhibition is amplified by high temperature and aridity (Sage 2004). Atmospheric CO2 concentration dropped below saturating levels 25-30 million years ago (Tipple & Pagani 2007), and the C4 photosynthetic pathway is hypothesized to have first evolved in warm, low latitude environments around this time (Christin et al. 2008a). The primary feature of C4 photosynthesis is suppression of O2 inhibition through concentration of CO2 around Rubisco. This pathway is estimated to have evolved almost 50 times across 19 angiosperm families (Muhaidat et al. 2007), a remarkable example of evolutionary convergence. In several C4 lineages, there are species with photosynthetic traits that are intermediate between the C3 and C4 states, known as C3-C4 intermediates. In two eudicot genera, Flaveria (Asteraceae) and Alternanthera (Amaranthaceae), there is evidence that these species represented an intermediate state in the evolution of the C4 pathway (McKown et al. 2005; Sanchez-del Pino 2009). The purpose of this thesis is to ascertain the specific benefits to plant carbon balance and resource-use efficiencies of the C3-C4 pathway relative to C3 species, particularly at low CO2 concentrations and high temperatures, factors which are thought to have been important in selecting for C3-C4 traits (Ehleringer et al. 1991). This will provide information on the particular advantages of the C3-C4 pathway in warm, often arid environments and how these advantages may have been important in advancing the initial stages of C4 evolution in eudicots. This thesis addresses the physiological intermediacy of previously uncharacterized C3-C4 species of Heliotropium (Boraginaceae); the water- and nitrogen-use efficiencies of C3-C4 species of Flaveria; and the photosynthetic performance and acclimation of C3, C4 and C3-C4 species of Heliotropium, Flaveria and Alternanthera grown at low and current ambient CO2 levels and high temperature.

The C3 photosynthetic pathway uses light energy to reduce CO2 to carbohydrates and other organic compounds and is a central component of biological metabolism. In C3 photosynthesis, CO2 assimilation is catalyzed by ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), which reacts with both CO2 and O2. While competitive inhibition of CO2 assimilation by oxygen is suppressed at high CO2 concentrations, O2 inhibition is substantial when CO2 concentration is low and O2 concentration is high; this inhibition is amplified by high temperature and aridity (Sage 2004). Atmospheric CO2 concentration dropped below saturating levels 25-30 million years ago (Tipple & Pagani 2007), and the C4 photosynthetic pathway is hypothesized to have first evolved in warm, low latitude environments around this time (Christin et al. 2008a). The primary feature of C4 photosynthesis is suppression of O2 inhibition through concentration of CO2 around Rubisco. This pathway is estimated to have evolved almost 50 times across 19 angiosperm families (Muhaidat et al. 2007), a remarkable example of evolutionary convergence. In several C4 lineages, there are species with photosynthetic traits that are intermediate between the C3 and C4 states, known as C3-C4 intermediates. In two eudicot genera, Flaveria (Asteraceae) and Alternanthera (Amaranthaceae), there is evidence that these species represented an intermediate state in the evolution of the C4 pathway (McKown et al. 2005; Sanchez-del Pino 2009). The purpose of this thesis is to ascertain the specific benefits to plant carbon balance and resource-use efficiencies of the C3-C4 pathway relative to C3 species, particularly at low CO2 concentrations and high temperatures, factors which are thought to have been important in selecting for C3-C4 traits (Ehleringer et al. 1991). This will provide information on the particular advantages of the C3-C4 pathway in warm, often arid environments and how these advantages may have been important in advancing the initial stages of C4 evolution in eudicots. This thesis addresses the physiological intermediacy of previously uncharacterized C3-C4 species of Heliotropium (Boraginaceae); the water- and nitrogen-use efficiencies of C3-C4 species of Flaveria; and the photosynthetic performance and acclimation of C3, C4 and C3-C4 species of Heliotropium, Flaveria and Alternanthera grown at low and current ambient CO2 levels and high temperature.

Techn. Hochsch., Diss., 2003--Aachen.

This thesis analyses whether the criticism that 20th c economic theory is too abstract, and lacking in economic meaning as a consequence of being mathematical, is justified, from a methodological perspective that is epistemological in character (cf ch2 and Cheix, 1996). Using, firstly the 'external' historical approach, that compares. Economics to the sciences (especially Mathematics chs 5, 6, 7, 8); and, secondly, the semiotic approach, that enquires into the contribution of notation to meaning, the thesis examines the historical and cognitive raison d'etre of mathematics in Economics. The thesis identifies (chs l, 2) 20th c mathematical-economics with model building and neoclassical theory. The main lines of argument are developed with reference to Jevons' Theory of Political Economy and Debreu's Theory of Value. This limitation is practical but not unnecessarily restrictive as the authors are major neo-classical writers, and mathematical economics has developed along the lines they envisaged. Further, neo-classical ideas have established themselves as paradigms of 20th c Economics, and have influenced theories in the social sciences and their mathematization. It is shown that Jevons (ch5) used the symbolism, and in particular, the linearity property of differentials to unify economic theory and the sciences on the pattern of Physics. For him however, the mathematization of economics involved also empirical and experimental inquiries using statistics. For the case of Debreu (ch6) it is shown how he used set-theoretic formalism and fixed point theorems to provide equilibrium theory with logico-mathematical content. This content is viewed as an axiomatic and deductive structure implying equilibrium. The definitions of mathematical economic models discussed in Part 3 show that economics was mathematized through influences not only from Physics, but also from Logic, and, more widely from the 20th c (socio-cultural) trend of model building in science. It is argued that this latter trend is not exclusively, or even necessarily, rooted in neo-classical economics. The semiotic analysis of chs 5 and 6 reveals how notations connect different interpretative levels ('isotopies') of mathematical theories, and how inconsistences may arise between these levels. The general conclusion of the thesis given certain methodological provisos, is that mathematization, in itself, is not a cause of, or explanation for, the emptiness of economic theories.

A study of the photo-alkylation of C4 hydrocarbons.

A síndrome Kranz é um conjunto de características anatômicas, ultra-estruturais e bioquímicas que culminam na realização da fotossíntese C4. Tal síndrome apresenta grande diversidade dentre as Angiospermas, tornando-se conveniente seu estudo em todos os níveis acima citados para a completa caracterização da mesma. No presente trabalho foi investigada a síndrome Kranz de Gomphrena arborescens e G. scapigera (Amaranthaceae) com ênfase na origem ontogenética da bainha Kranz, na descrição ultra-estrutural e na confirmação bioquímica sobre o tipo de fotossíntese C4. O desenvolvimento foliar dessas espécies indica que a bainha Kranz é originada da camada mais interna do mesofilo, a endoderme foliar. Uma discussão sobre os termos presentes na literatura para a descrição dessa bainha, todos eles focados em sua função na fotossíntese C4, demonstra a importância de se utilizar termos que informem a origem ontogenética dessa bainha, como endoderme e periciclo. Na análise ultra-estrutural, foram identificados possíveis fatores que interferem na fotossíntese de ambas as espécies, como o espessamento e a composição da parede da bainha Kranz, o posicionamento centrípeto dos cloroplastos e a presença de retículo periférico nos mesmos. Embora a análise bioquímica tenha resultado em informações ainda não conclusivas, o dimorfismo dos cloroplastos sugere a realização da fotossíntese C4 do tipo NADP-ME. O presente trabalho, de uma forma geral, contribui ao conhecimento da síndrome Kranz dentre as Amaranthaceae s.s., um grupo em que a ultra-estrutura e a bioquímica ainda são pouco conhecidas, e ressalta a importância dos estudos anatômicos, principalmente com enfoque ontogenético, para o melhor conhecimento da diversidade da síndrome Kranz dentre as Angiospermas. / The Kranz syndrome is a set of anatomical, ultrastructural and biochemical features that culminate in the C4 photosynthesis. This syndrome has a huge diversity among Angiosperms, so it became suitable to survey all the levels above cited for its complete characterization. In the present work the Kranz syndrome of Gomphrena arborescens and G. scapigera (Amaranthaceae) is studied, with emphasis on the ontogenetic origin of the Kranz sheath, on the ultrastructural description, and on the biochemical confirmation about the C4 photosynthesis kind. The foliar development of these species shows that the Kranz sheath is originated from the inner layer of the mesophyll, the foliar endodermis. A discussion about the literature terms used to describe the Kranz sheath, all of them referring to the function of this layer in C4 photosynthesis, demonstrates the importance of using terms that inform the ontogenetic origin of this layer, such as endodermis and perycicle. The ultrastructural analysis identified possible factors that interfere on the C4 photosynthesis of both species, such as wall thickening and composition of Kranz sheath cells, the centripetal position of chloroplasts and the peripheral reticulum in chloroplasts. Although biochemical analysis has resulted in no conclusive information, the chloroplast dimorphism suggests the NADP-ME C4 photosynthesis. This work, in a general way, contributes to the knowledge of the Kranz syndrome among Amaranthaceae s.s., a group that has the ultrastructure and the biochemistry of C4 photosynthesis poorly known. It also draws attention to the importance of anatomical surveys concerning the ontogenetic origin of Kranz sheath for a better understanding on the diversity of Kranz syndrome among Angiosperms.

C4 photosynthesis is an advanced complement to the more ancestral and more commonpathway refereed to as C3. C4 metabolism has evolved in several taxa, and it is theorized thatit worked as an adaptation to the low CO 2 levels characteristic of late geological time. Theadaptation also carries with it some resistance to the negative effects brought on by hightemperatures and drought. C4 metabolism is, however, not free, meaning that underconditions of lower temperature and higher CO2-levels, C3 photosynthesis is still moreviable. This makes it interesting to study how C4-species might shift their ranges in responseto climate change, as it implies both elevated CO 2 levels and higher mean temperatures inmost parts of the world. In this report, I develop a model based on the CO 2/O2 specificity of Rubisco from Spinach(Spinacia oleracea) at different temperatures, using data found in literature on the subject.The resulting model has some success in describing the current distribution of C4 species,using temperature and CO2 concentration as explanatory variables.