<p>The design and application of effective drug carriers is a fundamental concern in the delivery of therapeutics for the treatment of cancer and other vexing health problems. Traditionally utilized chemotherapeutics are limited in efficacy due to poor bioavailability as a result of their size and solubility as well as significant deleterious effects to healthy tissue through their inability to preferentially target pathological cells and tissues, especially in treatment of cancer. Thus, a major effort in the development of nanoscopic drug delivery vehicles for cancer treatment has focused on exploiting the inherent differences in tumor physiology and limiting the exposure of drugs to non-tumorous tissue, which is commonly achieved by encapsulation of chemotherapeutics within macromolecular or supramolecular carriers that incorporate targeting ligands and that enable controlled release. The overall aim of this work is to engineer a hybrid nanomaterial system comprised of protein and silica and to characterize its potential as an encapsulating drug carrier. The synthesis of silica, an attractive nanomaterial component because it is both biocompatible as well as structurally and chemically stable, within this system is catalyzed by self-assembled elastin-like polypeptide (ELP) micelles that incorporate of a class of biologically-inspired, silica-promoting peptides, silaffins. Furthermore, this methodology produces near-monodisperse, hybrid inorganic/micellar materials under mild reaction conditions such as temperature, pH and solvent. This work studies this material system along three avenues: 1) proof-of-concept silicification (i.e. the formation and deposition of silica upon organic materials) of ELP micellar templates, 2) encapsulation and pH-triggered release of small, hydrophobic chemotherapeutics, and 3) selective silicification of templates to potentiate retention of peptide targeting ability.</p> / Dissertation

This thesis study is concerned with genetical investigation of Balikesir Balya Pb-Zn mineralization through the mineralogic-petrographic and geochemical examination of the core samples obtained from a total of 9 holes drilled by EczacibaSi ESAN Madencilik. The Pb-Zn mineralization in Balya is mainly of vein-type. Wall rocks hosting mineralizations are dacite, dacite porphyry and microdiorite. Major types of alteration are silicification, carbonatization and calc-silicate alteration, each of which is further subdivided into early and late stages and overprinted by argillic alteration of probable supergene origin. The ore minerals are mainly Zn- and Pb-sulphides and are hosted by the rocks with late calc-silicate alteration that underwent pervasive late silicification and late carbonatization. Sulfide mineralization is spatially and temporally associated with the late silicification and carbonatization stages. Lateral-vertical correlation of drill logs suggest that thickness of the ore zone tends to decrease towards north. The volcanic rocks hosting the mineralization have calc-alkaline nature. Major, trace and rare earth element (REE) geochemistry suggests either crustal contamination or subduction signature in the mantle source of the volcanics. Multi element patterns and discrimination diagrams collectively point to a post-collisional setting for their generation. Alteration geochemistry reveals that Fe2O3 and CaO are enriched during calc-silicate alteration in contrast to depletion of SiO2. Al2O3 and TiO2 are almost constant during late calc-silicate alteration. Enrichment of Fe2O3 and Na2O, and depletion of K2O characterize the silicified zones. Carbonatization is accompanied by strong enrichment of CaO and depletion of SiO2, Al2O3 and K2O.

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La présente étude examine la variation de l’accumulation de la silice chez les graminées tropicales dans une perspective écologique et évolutive. La revue des travaux examinant l’étendue de la variation de la teneur en silice dans les graminées identifie trois groupes de facteurs influençant la silicification des graminées, notamment les facteurs génétiques (différence dans la capacité d’absorption racinaire, d’anatomie et de traits écophysiologiques foliaires), des facteurs endogènes (phénologie, organes végétaux) et les conditions de croissance. L’approche expérimentale a été orientée sur l’influence de certaines conditions de croissance sur la teneur en silice (défoliation, humidité, fertilité du substrat). Les résultats confirment l’influence de la défoliation et de la fertilité du substrat sur l’accumulation de la silice, mais soulignent bien la complexité de l’action de ces facteurs qui se traduit notamment par des différences de réponse entre espèces. Ces résultats suggèrent que les contradiction entre travaux publiés en ce qui concerne le caractère inductible ou non de l’accumulation de la silice sont dues pour partie à des interaction espèces*défoliation, et à une grande sensibilité des résultats aux conditions d’application de la défoliation. Les variations de la teneur en silice (intrinsèques et induites par les conditions de croissance) mises en relation avec les variations de traits structuraux et fonctionnels (surface foliaire spécifique, teneur en eau, anatomie foliaire, etc.) montrent des corrélations qui ne sont pas entièrement constantes au travers de tous les essais. Elles sont significativement positives avec les cendres solubles dans toutes les conditions de croissances examinées, mais négatives avec le carbone en condition de défoliation. Avec la teneur en eau, elles sont positives en conditions de défoliation, mais changent de signe en conditions de fertilisation phospho-azotée. Cette corrélation négative avec la teneur en eau est consistante à la fois dans les limbes et les gaines en comparaison interspécifique. Cette différence dans la structure des corrélations résulte à la fois des effets d’échantillonnage et l’étendue plus ou moins grande de la gamme des teneurs en silices balayées par les différentes espèces examinées. Pennisetum unisetum est la plus riche en silice et en sclérenchyme et qui pèse de façon disproportionnée dans l’analyse des corrélations. Les résultats n’apportent pas un soutien très clair à l’hypothèse selon laquelle la silice peut se substituer aux composés carbonés comme matériau de soutien. / The present study examines the variation of the silica accumulation of tropical grass species on the ecological and evolutionary point of view. The review of works examining the extent of the variation of the silica content in grasses identifies three groups of factors influencing the grass silicification, in particular the genetic factors (difference in the capacity of root absorption, anatomy and foliar ecophysiological features), endogenous factors (phenology, organs) and the growth conditions. The experimental approach focused the influence of certain conditions of growth on the silica content (defoliation, moisture, substrate fertility). The results confirm the influence of the defoliation and the substrate fertility on the silica accumulation, but underline well the complexity of the action of these factors which results in particular in differences in response between species. These results suggest that contradiction between published works with regard to the inducible character or not of the silica accumulation are due to some extent to the species*defoliation interaction, and a great sensitivity of the results to the conditions for application of defoliation. Variations of the silica content (intrinsic and induced by the growth conditions) relating to the variations of structural and functional characters (specific leaf area, water content, foliar anatomy, etc.) showed correlations which are not entirely constant through all the tests. They are significantly positive with soluble ashes under all the examined conditions, but negative with carbon in condition of defoliation. With the water content, they are positive in conditions of defoliation, but change sign in conditions of phospho-nitrogenized fertilization. This negative correlation with the water content is consistent at the same time in blades and sheaths in interspecific comparison. This difference in the structure of the correlations results at the same time from the effects of sampling and the more or less large extent of the range of the silica contents swept by the various examined species. Pennisetum unisetum is richest in silica and sclerenchyma and which weighs disproportionately in the analysis of correlations. The results do not give a very clear support for the assumption according to which silica can replace the carbonaceous compounds like material of support. / Doctorat en sciences agronomiques et ingénierie biologique / info:eu-repo/semantics/nonPublished

La pétroarchéologie du silex s’attache à définir les origines des silex retrouvés dans les sites archéologiques. Auvu des avancées méthodologiques récentes (définition toujours plus précise des faciès, vision dynamique duparcours du silex dans son environnement - chaîne évolutive -, mise en place d’une cartographie précise desdomaines minéraux siliceux) il est aujourd’hui possible de préciser non seulement le lieu de formation du silex(gîte primaire) mais également son lieu de collecte (gîte primaire ou secondaire).L’étude exhaustive des silex de collections archéologiques du sud du Massif central à plusieurs moments-clés duPaléolithique supérieur (Gravettien récent et final : Le Blot et Le Rond-de-Saint-Arcons ; Badegoulien : Le Ronddu-Barry et La Roche-à-Tavernat ; et Magdalénien supérieur : Sainte-Anne II) a permis la mise en évidence d’unediversité insoupçonnée de matériaux représentatifs d’un vaste litho-espace (espace géographique comprenantl’ensemble des matériaux considérés). Nous proposons donc un modèle de représentation de l’origine et del’acquisition des matières premières retrouvées sur un site archéologique, non plus sous une forme sito-centrée(en étoile), mais sous la forme d’un réseau de lieux, plus en accord avec les données issues des observationsethnographiques et géographiques. La représentation des différents types de matériaux au sein des industrieslithiques, ainsi que leurs modes d’introduction sur le site, permettent de distinguer les choix opérés par leshommes et les contraintes naturelles subies, autorisant dès lors l’inscription sémantique du litho-espace dans unessai de reconstruction du paléo-espace social. / The petroarchaeology of flint tries to define the origin of flints found in archaeological sites. In view of the recentmethodological advances (definition of the facies always more precise, dynamic vision of the route of the flint inher environment - “evolutionary chain” concept -, precise mapping of the siliceous mineral domains) it isnowadays possible to distinguish not only the formation place of the flint (primary outcrop) but also its retrievalplace (primary or secondary outrcrop).The exhaustive study of archaeological flint collections from the South of the Massif Central of France at varioustimes of the Upper Palaeolithic (recent and final Gravettian: Le Blot and Le Rond-de-Saint-Arcons; Badegoulian:Le Rond-du-Barry and La Roche-à-Tavernat; and Upper Magdalenian: Sainte-Anne II) have permitted thehighlighting of an unexpected diversity of material representative of a huge litho-espace (geographical spaceincluding all the regarded materials). In this respect, we developed a new figuration model of the origin of the rawmaterial discovered in the archaeological site, either in a sito-centred form (like a star), but like a network ofplaces, more in agreement with the ethnographic and geographic data. The presence of different types of flint inthe lithic industries correlated to their introducing pattern on site, allow to distinguish the choices made by theancient men versus the natural constraints they undergone, authorizing consequently the semantic inscription ofthe litho-espace in an attempt of reconstruction of the palaeo-social-space.