Stimuli-responsive polymers and self-assembling peptides represent two classes of materials with interesting properties and great potential to be used as biomaterials. The conjugation of polymer with peptide offers a way to combine the controlled chemical, mechanical, and thermal properties of polymer with the functionality of designed bioactive group. Pure hybrid materials with the characteristics of individual components or systems containing hybrid materials became attractive for applications in drug delivery and tissue engineering. This work focused on systems where the thermo-responsive properties of a polymer were combined with the gelling properties of two different ionic-complementary peptides via conjugation. The prototypical thermo-responsive polymer poly(N-isopropylacrylamide) (PNIPAAm) was chosen due to its lower critical solution temperature (LCST) ~32°C being close to body temperature. Ionic-complementary oligo-peptides, containing the alternating hydrophobic/hydrophilic and charged/uncharged amino acids, phenylalanine (F), glutamic acid (E) and lysine (K), were selected as they are known to form β-sheet rich fibrillar networks at low concentrations. Two peptide sequences with different charge distribution were chosen: FEFEFKFK and FEFKFEFK which form self-supporting gels at ~17 and 10 mg ml-1 respectively. Polymer-peptide conjugates were used to confer self-assembling and thermo-responsive behaviour to the system.Thermo-responsive PNIPAAm-rich hydrogels were obtained by targeting different degrees of functionalisation of PNIPAAm with the self-assembling peptides. Two series of such systems were prepared by using either a thiol-modified FEFEFKFK or a thiol-modified FEFKFEFK peptide as the chain-transfer agent in the free radical polymerisation of NIPAAm. The resulting polymer/conjugate mixtures were studied by proton nuclear magnetic resonance (1H NMR). The polymer/conjugate ratios were calculated and showed that the conjugate fraction in the mixtures increased with increasing concentration of peptide used for the polymerisation. Static light scattering (SLS) and viscometry showed the aggregation of the polymer/conjugate mixtures presumably due to the presence of peptide. The values from gel permeation chromatography (GPC), which were mostly attributed to the unconjugated polymers, were higher than those obtained from 1H NMR and centrifugation for the conjugates. The polymer/conjugate mixtures formed self-supporting gels where the critical gelation concentration decreased with increasing conjugate content. Oscillatory rheology experiments confirmed gels had formed and revealed that their elastic modulus, G' varied from ~ 10 to 400 Pa depending on the sample. TEM and AFM studies proved the formation of β-sheet fibres of ~ 4.5 ± 1.5 nm in diameter. The PNIPAAm-rich hydrogels were also characterised by micro DSC to reveal their thermo-responsiveness and phase separation and showed the LCST at ~ 30°C. The results of the study showed that varying the peptide sequence did not have an effect on thermal, mechanical or morphological properties of the hydrogels. By exploiting the self-assembly of the ionic-complementary peptides, it was possible to create PNIPAAm-rich, thermo-responsive hydrogels with controllable properties.Further in the study pure PNIPAAm-FEFEFKFK conjugate was incorporated into the FEFEFKFK peptide matrix to create peptide-rich thermo-responsive composite gels. Two series of the composite gels were prepared by varying separately the peptide matrix and polymer-peptide conjugate concentration. Micro DSC measurements revealed an endothermic peak at ~ 30ºC characteristic of the LCST of PNIPAAm. Oscillatory rheology studies showed that the composite gels became stronger with increasing conjugate concentration (G' ~ 20 - 200 Pa). Network morphology was studied by SANS. Using contrast variation and contrast matching techniques it was possible to distinguish between the peptide fibres and the PNIPAAm chains. Below and above the LCST the scattering curves showed a q-1 behaviour which is typical of rod-like objects. TEM and AFM also proved the formation of fibres of ~4.0 ± 0.8 nm and ~4.5 ± 1 nm respectively. AFM studies showed that the fibres of the composite gels were decorated with polymer chains. The thermo-responsiveness and the gelation properties of these conjugate-based scaffolds have potential for use as drug delivery vehicles or tissue engineering scaffolds.

The Streptomyces metabolite 2-crotonyloxymethyl-(4R,5R,6R)-4,5,6-trihydroxycyclohex-2-enone (COTC), the antheminones and the carvotacetone derivatives are all bioactive natural products, whose structure is based on the α oxymethyl-a,β-cyclohexenone moiety. Both COTC and antheminone A have been shown to exhibit cytotoxic and cancerostatic activity with low toxicity. The potent biological activity of these natural products has instigated numerous investigations into the synthesis of novel analogues in an attempt to determine the key structural features necessary for optimum bioactivity. The synthesis of a small library of novel anti-tumour agents which are structurally related to the natural products COTC and antheminone A is described, using the chiral pool material (-)-quinic acid as a starting material. At the outset, the aim of this project was to develop and optimise copper-mediated conjugate addition reactions and rhodium catalysed conjugate addition reactions of organoboron reagents to functionalised cyclic enones and subsequently, to apply the methodologies to the synthesis of the novel analogues. A range of novel mono-hydroxylated analogues bearing aryl side chains were prepared and their antiproliferative activity was assessed towards the A549 non-small cell cancer cell line. The biological assays revealed important structure-activity relationships and the most bioactive compound of this series had an IC50 value of 1.2 µM. In addition, the design and synthesis of a new class of GSH-activated prodrugs is described. These novel compounds are activated by GSH leading to intracellular release of an NQO1 inhibitor. The most potent compound of this new class of compounds had an IC50 value of 710 nm.

ELTs equipped with MCAO systems will be powerful astrometric tools in the next two decades. With sparse-field precisions exceeding 30 uas for V > 18, the ELTs will surpass even GAIA's per-epoch precision for faint stars (V > 12). We present results from an ongoing astrometry program with Gemini GeMS and discuss synergies with WFIRST and GAIA. First, we present a fit to the relative orbit of the individual L/T components of Luhman16 AB, the nearest brown dwarf binary known. Exploiting GeMS' wide field of view to image reference stars, we are able to track the relative motion to better than 0.2 mas. We find that a mutual Keplerian orbit with no perturbing planets fits the binary separation to within the measurement errors, ruling out companions down to 14 earth masses for certain orbits and periods.

Orientadores: Aurélio Ribeiro Leite de Oliveira, Marta Ines Velazco Fontova / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-18T12:49:39Z (GMT). No. of bitstreams: 1 Coelho_AlessandroFonsecaEsteves_M.pdf: 2659631 bytes, checksum: fc1bec925179612ee07a4aaef7092d8a (MD5) Previous issue date: 2011 / Resumo: Um método frequentemente utilizado para a solução de problemas de programação linear é o método de pontos interiores. Nestes métodos precisamos resolver sistemas lineares para calcular a direção de Newton a cada iteração. A solução desses sistemas consiste no passo de maior esforço computacional nos métodos de pontos interiores. A fatoração de Cholesky é a opção mais utilizada para resolver estes sistemas. Contudo, quando trabalhamos com problemas de grande porte, esta fatoração pode ser densa e torna-se inviável trabalhar com esses métodos. Nestes casos, uma boa opção consiste no uso de métodos iterativos precondicionados. Estudos anteriores utilizam o método dos gradientes conjugados precondicionado para obter uma solução destes sistemas. Particularmente, os sistemas originados dos métodos de pontos interiores, são, naturalmente, sistemas de equações normais. Porém, a versão padrão do método dos gradientes conjugados, não considera a estrutura de equações normais do sistema. Neste trabalho propomos a utilização de duas versões do método de gradientes conjugados precondicionado que consideram a estrutura de equações normais destes sistemas. Estas versões serão comparadas com a versão de gradientes conjugados precondicionada que não considera a estrutura de equações normais do sistema. Resultados numéricos com problemas de grande porte mostram que uma dessas versões é competitiva em relação à versão padrão / Abstract: An often used method for solving linear programming problems is the interior point method. In these methods we need to solve linear systems to compute the Newton search direction at each iteration. The solution of these systems is the procedure of most computational effort in interior point methods. The Cholesky factorization is the most often used method to solve these systems. However, when dealing with large scale problems, this factorization can be dense and it become impossible to apply such methods. In such cases, a good option is the use of preconditioned iterative methods. Previous studies have used the preconditioned conjugate gradient method to find the solution of these systems. Particularly, the systems arising from interior point methods are, naturally, systems of normal equations type. Nevertheless, the standard version of the conjugate gradient method, does not take into account the normal equations system structure. This study proposes the use of two versions of preconditioned conjugate gradient method considering the normal equations structure of these systems. These versions are compared with the preconditioned conjugate gradient version that does not consider that structure. Numerical results with large scale problems show that one of these versions is competitive with the standard one / Mestrado / Matematica Aplicada / Mestre em Matemática Aplicada

Haemophilus influenzae type b (Hib) é uma importante bactéria Gram-negativa causadora de pneumonia, meningite e septicemia em crianças abaixo dos 5 anos de idade. A prevenção contra a doença pode ser alcançada pela imunização da população com vacina conjugada polissacarídeo-proteína, uma vez que a vacina de polissacarídeo não é eficiente. As vacinas conjugadas disponíveis comercialmente custam para o governo brasileiro cerca de US2,7 a dose, sendo necessárias no mínimo 3 doses para imunização completa. O presente estudo desenvolveu um novo método de conjugação de polissacarídeo capsular de Hib (PRP) com toxóide tetânico (TT). O método hidrazona baseia-se em 3 etapas simples: oxidação e derivatização de PRP com espaçador molecular e conjugação com TT na presença de uma carbodiimida e de um éster amino reativo. Após um estudo detalhado de cada etapa do método hidrazona, o novo processo mostrou excelentes resultados de rendimento mesmo após escalonamento. A imunogenicidade e o índice de avidez do conjugado hidrazona foram avaliados e os resultados encontrados foram comparáveis a vacina comercial Hiberix®. A técnica de HPSEC mostrou-se eficaz e o perfil cromatográfico do conjugado hidrazona foi muito similar ao da vacina Hiberix. Finalmente, o novo processo de conjugação de vacina permitiu o desenvolvimento de uma poderosa tecnologia constituindo uma excelente opção para o governo brasileiro. / Haemophilus influenzae type b (Hib) is an important encapsulated bacteria, which causes pneumonia, meningitis and septicaemia in infants. Prevention against infection is achieved by the currently available polysaccharide protein conjugate vaccine. However, due to its high production costs (around U$ 2,7 per dose) this formulation cannot be used in mass immunization programs in Brazil. In the present study, we developed a new method for the conjugation of Hib polysaccharide (PRP) and tetanus toxoid (TT). The hydrazone method is based on 3 singles steps: PRP oxidation, PRP derivatization with linker spacer and conjugation with TT in the presence of carbodiimide and an amino reactive ester. After detailed study of each step of method, the new process showed very good yield of conjugation even when it was scaled-up. The immunogenicity and the avidity index of hydrazone conjugate were evaluated and the results were comparable with those obtained with the commercial vaccine Hiberix®. The HPLC hydrazone profile was very similar to HPLC Hiberix profile. Finally, the new conjugation process allows the development of a powerful vaccine technology, constituting an excellent choice for the brazilian government.

There is a long history of interesting connections between topological dynamical systems and C*-algebras. Iterated function systems are an important topic in dynamics, but the diversity of these systems makes it challenging to develop an associated class of C*-algebras. Kajiwara and Watatani were the first to construct a C*-algebra from an iterated function system. They used an algebraic approach involving Cuntz-Pimsner algebras; however, when investigating properties such as ideal structure, they needed to assume that the functions in the system are the inverse branches of a continuous map. This excludes many famous examples, such as the standard functions used to construct the Siérpinski Gasket. In this thesis, we provide a construction of an inductive limit of étale equivalence relations for a broad class of affine iterated function systems, including the Siérpinski Gasket and its relatives, and consider the associated C*-algebras. This approach provides a more dynamical perspective, leading to interesting results that emphasize how properties of the dynamics appear in the C*-algebras. In particular, we show that the C*-algebras are isomorphic for conjugate systems, and find ideals related to the open set condition. In the case of the Siérpinski Gasket, we find explicit isomorphisms to subalgebras of the continuous functions from the attractor to a matrix algebra. Finally, we consider the K-theory of the inductive limit of these algebras. / Graduate

L’objectif des travaux de cette thèse était de développer un système de délivrance stimulus-sensible innovant. Basé sur des vésicules lipidiques, il permet la libération d’une substance anti-cancéreuse hydrophile encapsulée dans leur cœur aqueux, sous l’effet de la lumière. Des porphyrines, incorporées dans leur bicouche, permettent, une fois illuminées, de générer de l’oxygène singulet qui oxyde les chaînes acyl insaturées des phospholipides. Cela induit une augmentation de la perméabilité des liposomes et permet la libération de leur cargo. Nous avons, dans un premier temps, effectué une sélection de phospholipides et de porphyrines permettant de construire le système. Les résultats expérimentaux ont pu être corrélés à une étude de simulation de dynamique moléculaire. L’ensemble a mis en exergue l’importance de la profondeur d’insertion de la porphyrine dans la bicouche lipidique et de sa proximité avec la double-liaison des phospholipides. Mais il a aussi montré les limites de ce système. Nous avons alors développé deux nouvelles molécules, dérivées de phospholipides naturels auxquels a été couplée la pheophorbide a. Malgré leur possible autoassemblage sous la forme de vésicules, ces derniers n’étaient pas stables et s’agrégeaient rapidement. Nous avons donc associé ces conjugués à des lipides classiques (DSPC, cholestérol) et analysé les propriétés des mélanges obtenus. Les propriétés photothermiques des systèmes conçus ont été confirmées, capables d’induire une élévation en température de 14°C. La chaleur générée, responsable d’une plus grande fluidité de la bicouche lipidique, a permis de favoriser la libération du cargo. Enfin, les deux conjugués synthétisés ont montré eux-mêmes une activité phototoxique (PDT), additionnée d’une sélectivité vis-à-vis de cellules du cancer de l’œsophage. Ces nouvelles molécules offrent donc de nombreuses opportunités pour le développement de systèmes multimodaux, bio-inspirés et biodégradables, pour la délivrance d’un médicament sous l’effet de la lumière. / The aim of this work was to develop an innovative stimulus-responsive delivery system. Based on lipid vesicles, it allows the controlled release, by light, of a hydrophilic anti-cancer substance encapsulated in their aqueous core. Once illuminated, porphyrin molecules inserted into the lipidic bilayer, generate singlet oxygen which oxidizes the unsaturated acyl chains of the phospholipids. This induces an increase in the permeability of the liposomes and the release of their cargo. We first made a selection of phospholipids and porphyrins to build the system. Our experimental study could be correlated with results of molecular dynamics simulations. The whole work highlighted the importance of the depth of insertion of porphyrin into the lipid bilayer and its proximity to the double bond of phospholipids. But it also showed the limits of this system. We then developed two new molecules, derived from natural phospholipids, to which pheophorbide a was coupled. The conjugates were able to form self-assembled vesicles but were unstable and quickly aggregated. We therefore associated these conjugates with classical lipids (DSPC, cholesterol) and analyzed the properties of these mixtures. We highlighted photothermal properties of the designed systems, capable of inducing a temperature rise of 14 °C. The generation of heat, responsible for a greater fluidity of the lipid bilayer, subsequently promoted the encapsulated cargo release. Finally, the two synthesized conjugates showed a phototoxic activity (PDT), with selectivity towards esophageal cancer cells. These new molecules therefore offer many opportunities for the development of multimodal, bio-inspired and biodegradable systems, for the delivery of a drug under the effect of light.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23036号 / 理博第4713号 / 新制||理||1675(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)准教授 加納 太一, 教授 時任 宣博, 教授 依光 英樹 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Two alternative technologies of communication inside a parallelized Conjugate-Gradient algorithm are presented and compared to the well known hypercubecommunication. The amount of communication is diskussed in detail. A large range of numerical results corroborate the theoretical investigations.

Millions of people worldwide die of cancer every year. In the last decade, im- munotherapy offered new treatment options achieving long-lasting remissions in a number of patients. Several new immunotherapy-based drugs have been ap- proved by Food and Drug Administration. However, majority of patients either do not respond or soon relapse. Combination of therapies as well as exploring new immune checkpoints seems promising. This thesis focuses on the new immunotherapeutic target CD73. CD73 is membrane ectonucleotidase, widely expressed on the regulatory leukocytes and on cancer cells. The enzymatically active CD73 contributes to the tumour mi- croenvironment by production of immunosuppressive adenosine. This novel im- mune checkpoint is being intensively studied. This thesis aims on development of new approaches for targeting and inhibition of CD73. Soluble recombinant CD73 (rhCD73) was prepared in mammalian expression system and transfectants stably expressing membrane-bound CD73 were prepared as well. Inhibitors necessary for both of my goals have been designed based on published inhibitor of CD73. Development and evaluation of novel antibody mimetic for CD73 characteri- sation was done. The so-called iBody, HPMA polymer conjugate decorated with CD73 inhibitor for targeting, fluorophore for...