Quantitative structure-activity relationships (OSAR) constitute empirical analogy models connecting chemical structure and biological activity. The analogy approach to QSAR assume that the factors important in the biological system also are contained in chemical model systems. The development of a QSAR can be divided into subproblems: 1. to quantify chemical structure in terms of latent variables expressing analogy, 2. to design test series of compounds, 3. to measure biological activity and 4. to construct a mathematical model connecting chemical structure and biological activity. In this thesis it is proposed that many possibly relevant descriptors should be considered simultaneously in order to efficiently capture the unknown factors inherent in the descriptors. The importance of multivariately and multipositionally varied test series is discussed. Multivariate projection methods such as PCA and PLS are shown to be appropriate far QSAR and to closely correspond to the analogy assumption. The multivariate analogy approach is applied to a beta- adrenergic agents, b haloalkanes, c halogenated ethyl methyl ethers and d four different families of peptides. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1986, härtill 8 uppsatser</p> / digitalisering@umu

Disinfectants in drinking water can interact with natural organic matter (NOM) to form disinfection by-products (DBPs). Halogenated furanones (including MX and MCA) are a group of emerging DBPs that can account for a significant amount of the total mutagenicity found in drinking water. Source water characteristics and NOM removal capabilities of coagulation can greatly influence the formation of DBPs. This project examines the effects of bench scale coagulation and chlorination tests on NOM removal, DBP formation, and genotoxicity. NOM was characterized using liquid chromatography-organic carbon detection (LC-OCD). Experiments with Ottawa River, Otonabee River, and Lake Simcoe waters show that DBPs decreased with increases in coagulant dosage, due to the removal of NOM during coagulation. DBP formation and speciation was then compared with NOM content to identify specific fractions that contribute to the formation of these DBPs. Genotoxicity was directly linked to MX presence in chlorinated waters.

Demosponges of the order Verongida such as Ianthella basta exhibit skeletons containing spongin, a collagenous protein, and chitin. Moreover, Verongida sponges are well known to produce bioactive brominated tyrosine derivatives. We recently demonstrated that brominated compounds do not only occur in the cellular matrix but also in the skeletons of the marine sponges Aplysina cavernicola and I. basta. Further investigations revealed the amino acid composition of the skeletons of A. cavernicola including the presence of several halogenated amino acids. In the present work, we investigated the skeletal amino acid composition of the demosponge I. basta, which belongs to the Ianthellidae family, and compared it with that of A. cavernicola from the Aplysinidae family. Seventeen proteinogenic and five non-proteinogenic amino acids were detected in I. basta. Abundantly occurring amino acids like glycine and hydroxyproline show the similarity of I. basta and A. cavernicola and confirm the collagenous nature of their sponging fibers. We also detected nine halogenated tyrosines as an integral part of I. basta skeletons. Since both sponges contain a broad variety of halogenated amino acids, this seems to be characteristic for Verongida sponges. The observed differences of the amino acid composition confirm that spongin exhibits a certain degree of variability even among the members of the order Verongida.

This diploma thesis focuses on possibilities of applications of UV radiation to remove pollutants from water. It summarizes sources of UV radiation and list their benefits and properties. The thesis characterizes so called advanced oxidation processes using UV light. Degradation pathways od pyridine and its derivatives especially halogenated pyridines are described. The photodegradability of pyridine and a rate of this reaction in model water is investigated in the experimental part. Also, the effect of concentration and dose of H2O2 is assessed. Gas chromatography was used to determinate concentrations of pyridine in samples.

L'utilisation des microcapsules fabriquées à partir de matériaux respectueux de l'environnement pour des applications textiles médicales a été étudiée et développée fortement au cours des dernières années. Le but de cette thèse est d'élaborer les textiles anti-inflammatoires à base de microcapsules respectueuses de l'environnement, utilisant trois types de matériaux textiles (coton, peco 65/35 et polyester) et cinq niveaux de longueur de boucle (2.81, 2.83, 2.87, 2,96 et 3,05 mm) sur étoffes tricotées à verrouillage de coton (nombre de fils Ne40). Les influences de la concentration en saponine, de la vitesse d'agitation au cours de l'étape d'émulsification et du volume d'éthyle acétate ajouté à la phase aqueuse sur les caractéristiques des microcapsules ont été étudiées. L'étude a également étudié les effets du rapport massique du coton et de la longueur de boucle des étoffes tricotées sur la distribution des microcapsules, la capacité de chargement des microcapsules et la capacité de libération de l'ibuprofène des étoffes tricotées traités par microcapsules. Les microcapsules d'Eudragit RSPO contenant de l'ibuprofène ont été élaborées par la technique d'évaporation de solvant, en utilisant le tensioactif bio-sourcé quillaja saponine et le solvant non halogéné d'éthyle acétate. Les microcapsules obtenues présentaient les formes sphériques avec un diamètre d (0,5) de 21,5 μm, approprié pour les applications textiles. Il a été trouvé que, pour empêcher la déformation des microcapsules pendant la traitement du textile, la séchage doit être effectuée sous vide à 45 ° C. Lorsque le rapport de teneur en fibres de coton dans le tissu augmentait, la distribution des microcapsules était moins régulière, ce qui entraînait un taux de libération plus faible de l'ibuprofène à partir des étoffes tricotées traités aux microcapsules. En outre, lorsque la longueur de la boucle augmente, la capacité de chargement des microcapsules des étoffes tricotées traités augmente, la distribution des microcapsules sur le tissu devient moins régulière et la vitesse de libération de l'ibuprofène des tissus traités aux microcapsules diminue. De plus, l'augmentation de l'extension du étoffes tricotées a favorisé la libération d'ibuprofène à partir des étoffes tricotées traités par les microcapsules à travers la peau de porc / The use of the microcapsules made from eco-friendly materials for medical textile applications has been researched and developed strongly in recent years. The aim of this thesis is to elaborate the anti-inflammatory textiles basing on eco-friendly microcapsules,using three kinds of textile materials (cotton, peco 65/35 and polyester)and five levels of the loop length (2.81, 2.83, 2.87, 2.96 and 3.05 mm) on the cotton interlock knitted fabrics (yarn count Ne40). The influences of the saponin concentration, the stirring rate during the emulsification step and the volume of ethyl acetate added to the aqueous phase on the characteristics of the microcapsules were studied. The influence of condition in drying on microcapsule’s morphology was also investigated.The thesis also researched the effects of cotton mass ratio and loop length of fabric on the microcapsule distribution, the microcapsule loading capability and the release capability of ibuprofen from the microcapsule treated fabrics. The Eudragit RSPO microcapsules containing ibuprofen were successfully elaborated by solvent evaporation technique, using the bio-sourced surfactant quillajasaponin and the non-halogenated solvent ethyl acetate. The obtained microcapsules exhibited the spherical shapes with d(0.5) diameter of 21.5 m, suitable for the textile applications. It was found that in order to keep the microcapsules from deformation during the textile finishing, the drying stage should be carried out in vacuum at 45oC. When the content ratio of cotton fibers in the fabric increased,the microcapsule distribution was less even, resulting in the lower release rate of ibuprofen from the microcapsule-treated fabrics. Besides, when the loop length increased, the microcapsule loading capability of the treated fabrics increased, the microcapsule distribution on the fabric became less even and the release rate of ibuprofen from the microcapsule-treated fabrics decreased. Furthermore, increasing the fabric extension favored the release of ibuprofen from the microcapsule-treated fabrics through the pigskin

No description available.

[FR] L'énergie photovoltaïque se présente comme une solution primordiale dans la lutte contre le réchauffement climatique. Malgré la maturité et la fiabilité de la technologie des cellules en silicium cristallin, les défis liés à la purification énergivore du silicium restent un obstacle coûteux. Dans cette optique, les pérovskites halogénées, notamment le FAPbI3, se profilent comme des alternatives prometteuses au silicium en raison de leur capacité à être synthétisées à faible coût à température ambiante, tout en présentant des propriétés optiques et électroniques attractives. Cependant, l'instabilité des pérovskites en contact avec l'air ambiant constitue un obstacle majeur à leur utilisation comme couche absorbante. Pour surmonter ce défi, une approche a consisté à modifier la composition chimique des pérovskites en utilisant la technique du spin-coating. L'étude a révélé que les pérovskites mixtes contenant de l'iodure (I) et du brome (Br), tels que le FAPbI2Br et le FAPbBr2I, offrent un compromis intéressant entre stabilité et bande interdite. Contrairement au FAPbI3, qui perd ses propriétés optiques après un certain temps en conditions ambiantes, ces pérovskites mixtes conservent leur capacité d'absorption dans le visible même après vieillissement. De plus, le FAPbBr2I s'est avéré environ trois fois plus photoluminescent que le FAPbI3, suggérant une conversion plus efficace des photons absorbés en paires électron-trou, ce qui en fait un candidat attractif pour les applications photovoltaïques. Cependant, il convient de noter que le FAPbBr2I présente un gap énergétique trop large pour de telles applications. Pour remédier à cette limitation, le dopage du FAPbBr2I avec du bismuth a été étudié, montrant une réduction significative du gap énergétique avec l'augmentation de la concentration en bismuth. Néanmoins, il a été observé que les photons émis par photoluminescence avaient une énergie supérieure à celle des photons absorbés, ce qui pourrait être dû à la dissipation de la chaleur dans le réseau cristallin. Ce décalage anti-Stokes nécessite une enquête plus approfondie. / [ES] La energía fotovoltaica se presenta como una solución clave en la lucha contra el calentamiento global. A pesar de la madurez y confiabilidad de la tecnología de células de silicio cristalino, los desafíos de la purificación de silicio intensiva en energía siguen siendo un obstáculo costoso. Con esto en mente, las perovskitas halogenadas, especialmente FAPbI3, están emergiendo como alternativas prometedoras al silicio debido a su capacidad de ser sintetizadas a bajo costo a temperatura ambiente, aunque tiene propiedades ópticas y electrónicas atractivas. Sin embargo, la inestabilidad de las perovskitas en contacto con el aire ambiente constituye un obstáculo importante para su uso como capa absorbente. Para superar este desafío, un enfoque fue modificar la composición química de las perovskitas utilizando la técnica de recubrimiento por centrifugación. El estudio reveló que las perovskitas mixtas que contienen yoduro (I) y bromo (Br), como FAPbI2Br y FAPbBr2I, ofrecen un compromiso interesante entre la estabilidad y la brecha de banda. A diferencia de FAPbI3, que pierde sus propiedades ópticas después de un cierto tiempo en condiciones ambientales, estas perovskitas mixtas conservan su capacidad de absorción en el visible incluso después del envejecimiento. Además, se encontró que FAPbBr2I era aproximadamente tres veces más fotoluminiscente que FAPbI3, lo que sugiere una conversión más eficiente de los fotones absorbidos en pares electrón-agujero, y, esto lo convierte en un candidato atractivo para aplicaciones fotovoltaicas. Sin embargo, debe tenerse en cuenta que FAPbBr2I tiene una brecha de energía más amplia que la ideal para tales aplicaciones. Para superar esta limitación, se estudió el dopaje de FAPbBr2I con bismuto, mostrando una reducción significativa de la brecha energética con el aumento de la concentración de bismuto. Sin embargo, se ha observado que los fotones emitidos por la fotoluminiscencia tienen una energía superior a la de los fotones absorbidos, y, esto podría deberse a la disipación de calor en la red cristalina. Este retraso anti-Stokes requiere más investigación. / [EN] Photovoltaic energy emerges as a crucial solution in the fight against climate change. Despite the maturity and reliability of crystalline silicon cell technology, challenges related to the energy-intensive purification of silicon remain a costly barrier. In this context, halide perovskites, especially FAPbI3, are emerging as promising alternatives to silicon due to their ability to be synthesized cost-effectively at room temperature while exhibiting attractive optical and electronic properties. However, the instability of perovskites in contact with ambient air poses a major obstacle to their use as an absorbing layer. To overcome this challenge, one approach has been to modify the chemical composition of perovskites using the spin-coating technique. The study revealed that misted perovskites containing iodide (I) and bromide (Br), such as FAPbI2Br and FAPbBr2I, offer an interesting compromise between stability and bandgap. Unlike FAPbI3, which loses its optical properties after some time under ambient conditions, these misted perovskites retain their absorption capacity in the visible range even after aging. Furthermore, FAPbBr2I was found to be approximately three times more photoluminescent than FAPbI3, suggesting a more efficient conversion of absorbed photons into electron-hole pairs, making it an attractive candidate for photovoltaic applications. However, it is worth noting that FAPbBr2I has a wider energy gap than ideal for such applications. To address this limitation, doping FAPbBr2I with bismuth was studied, showing a significant reduction in the energy gap with increasing bismuth concentration. Nevertheless, it was observed that the photons emitted by photoluminescence had higher energy than those absorbed, which could be due to heat dissipation in the crystal lattice. This anti-Stokes shift requires further investigation. / Abdoulaye, T. (2024). Etude de stabilité des pérovskites aux halogénures mixtes plombate de Formamidinium FAPbX3 avec X={ Cl,Br,I} [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203190

3-Chloro-4,4,5-trimethyl-3,5-diphenyl-4,5-dihydro-3H-pyrazole (3b) and 3-bromo-4,4,5-trimethyl-3,5-diphenyl-4,5-dihydro-3H-pyrazole (3c) were prepared for the thermolysis project. The thermal decompositions of 3b and 3c were monitored using 1H NMR spectroscopy. Plots of ln (% starting material) vs. time (sec) were linear for at least two half lives and the first order rate constants were determined over at least a 30o temperature range. The relative reactivity was found to be 3c > 3b. The activation parameters determined for the thermal decomposition of the pyrazoline at 150oC were found to be: for 3b &#;H‡ = 33 &#;1.0 kcal/mol, &#;S‡ = -2.4 &#; 0.07eu , k150 0 = 7.34 &#; 0.44 x 10 -5 s-1 ; for 3c &#;H‡ = 30&#;0.2 kcal/mol, &#;S‡ = -6.9 &#;0.03 eu, k150o = 42.3&#;0.7 x 10-5 s-1. Thermal decomposition of 3b both neat and in dibromobenzene (DBB) resulted in the formation of an intermediate 2,3-diphenyl-4-methyl-1,3-pentadiene (8) as a major product and minor isomers of 8. These intermediates then thermally decomposed to 1,1,3-trimethyl-2-phenyl-1H-indene (9) via an acid catalyzed process. In order to gain a mechanistic understanding (ionic vs. radical pathways) of the thermal decomposition of 3b, a product study was conducted in protic solvents. In methanol and ethanol, 3b underwent an ionic reaction (SN1-type) with the solvent to produce 3-methoxy/ethoxy-4,4,5-trimethyl-3,5-diphenyl-4,5-dihydro-3H-pyrazole (3/3d) in good yield. The reaction of 3b with refluxing protic solvents led to the development of new method for the synthesis of alkoxy-4,5-dihydro-3H-pyrazoles which is both safe and efficient.

This thesis is an investigation of the natural products deriving from marine algae and cyanobacteria and has resulted in the discovery of eleven new secondary metabolites. The structure elucidations of these new molecules were performed using a variety of spectroscopic techniques. Four new macrolides were isolated and characterized from the Madagascar marine cyanobacterium Geitlerinema sp. These ankaraholides are structurally similar to the potently cytotoxic swinholides and were found to have cytotoxicities ranging from 178 nM to 354 nM against human lung cancer (NCI-H460) and mouse neuro-2a cell lines. Since swinholide-type compounds were previously localized to the heterotrophic bacteria of sponges, these findings raise intriguing questions about their true metabolic source. Geitlerinema sp. was found to be particularly rich in chemistry, and also produced the new linear lipopeptide mitsoamide with unusual structural features including an aminal moiety, a homolysine residue and a polyketide unit (3,7- dimethoxy-5-methyl- nonanedioic acid) (DMNA). A collection of the red marine alga Portieria hornemannii from the south of Madagascar (Tolagniaro, Fort Dauphin), led to the isolation of the previously reported halogenated monoterpene, halomon, and the discovery of three new related metabolites. These molecules were found to inhibit DNA methyltransferase 1 (DNMT-1). As a result of efforts to identify bioactive agents from the marine cyanobacterium Lyngbya majuscula, tanikolide dimer, a novel SIRT2 inhibitor (IC50 = 176 nM), and tanikolide seco-acid were isolated. The depside molecular structure of tanikolide dimer, which is likely a meso compound, was established by NMR, MS and chiral HPLC analyses. The structure of tanikolide dimer raises a number of intriguing configurational and biosynthetic questions for further study. The bioassay guided fractionation of a collection of the brown marine alga Dictyota sp. from Netherland Antilles Playa Fort, led to the identification of a novel HDAC inhibitor with a dolastane carbon skeleton. The novel molecule was also found to possess antimalarial activity. Other known HDAC inhibitors with interesting antimalarial activity have been reported previously, and based on this efficacy against malaria, HDAC appears to be a viable target for the development of antiparasitic agents. / Graduation date: 2006

O ambiente marinho desponta como uma fonte natural importante devido à sua fantástica diversidade orgânica, que permanece praticamente inexplorada. Abordagens químicas e biológicas de organismos marinhos, atualmente, representam uma área de pesquisa ampla e promissora, visto a constante descoberta de diversos metabólitos com propriedades medicinais variadas, além de um arsenal metabólico praticamente ilimitado. Algas vermelhas, com destaque para a família Rhodomelaceae, são exímias produtoras de metabólitos halogenados aos quais são atribuídos importantes atividades biológicas. Micro-organismos marinhos e/ou endofíticos são apontados como os alvos mais promissores para descoberta de novos fármacos. Neste contexto, o presente trabalho descreve a identificação de metabólitos secundários da macroalga Bostrychia tenella (Rhodomelaceae, Rhodophyta), a qual possui poucos relatos na literatura a respeito de seu metabolismo secundário, bem como o potencial biológico de micro-organismos endofíticos associados a esta espécie. O estudo químico da espécie B. tenella coletada nos costões rochosos da Praia da Fortaleza (Ubatuba-SP) proporcionou a identificação, por meio de análises via CG-EM (fração acetato), de 63 metabólitos dos quais 39 são substâncias apolares de cadeias carbônicas longas (ex. ácidos graxos e ésteres, esteróides, dentre outros) e 24 são metabólitos fenólicos, incluindo 17 halofenóis clorados, bromados e iodados. Destas 24 substâncias, até o presente momento, três são inéditas, nove são inéditas como produtos naturais, quatro são inéditas em algas marinhas e seis são inéditas para o gênero Bostrychia. Adicionalmente, 45 linhagens de micro-organismos endofíticos foram isoladas da alga Bostrychia tenella, das quais 10 foram cultivadas em meio sólido arroz, proporcionando a obtenção de extratos brutos e frações orgânicas. Apesar das frações de B. tenella não terem exibido atividade biológica, extratos e frações dos micro-organismos endofíticos associados a esta espécie apresentaram-se ativos em todos os ensaios realizados: citotoxicidade utilizando células tumorais HL-60, HCT-8 e SF-295, antifúngico utilizando fitopatógenos Cladosporium cladosporioides e C. sphaerospermum, antibacteriano utilizando Staphylococcus aureus e Klebsiella pneumoniae, e inibição da degranulação mastocitária utilizando células RBL-2H3. O presente trabalho contribuiu para aumento do conhecimento sobre o metabolismo secundário da alga Bostrychia tenella e proporcionou a descoberta do potencial biológico de micro-organismos endofíticos associados a esta alga, atribuindo a esta espécie relevância química e microbiológica para o estudo de produtos naturais marinhos. / The marine environment appears as an important natural source due to its fantastic organic diversity, which practically remains unexplored. Chemical and biological approaches concerning marine organism, currently, represent an ample and promising research area, since there are a constant metabolite discovery with a variety of medicinal properties, besides the limitless metabolic armory. Red seaweeds, with distinction for the Rhodomelaceae family, are exempt of halogenated metabolites producers which are attributed important biological activities. Marine and/or endophytic microorganisms are pointed as the most promising targets with respect to discovery of new pharmaceuticals. In this context, the present work describes the secondary metabolites identification from seaweed Bostrychia tenella (Rhodomelaceae, Rhodophyta), as well as the biological potential of associated endophytic microorganisms. The chemical study of B. tenella species collected in the rocky shore of Praia de Fortaleza (Ubatuba-SP) provided the identification, by means of GC-MS analyses (acetate fraction), of 63 metabolites, which 39 consisted of nonpolar substances containing a long carbonic chains (fatty acids, esters, steroids, amongst others) and 24 were phenolic compounds, including 17 chlorinated, bromated and iodized halophenols. Related to these 24 substances, until the present moment, three are unknown, nine are unknown as natural products, four are unknown in seaweeds and six are unknown in the Bostrychia genus. Additionally, 45 endophytic microorganism strains had been isolated from B. tenella, from which 10 were cultivated in solid rice medium, providing several crude extracts and fractions. Although the B. tenella fractions did not show biological potential, extracts and fractions from endophytic microorganism associates to this species presented biological activity in all of evaluated assays: cytotoxicity using tumor cells HL-60, HCT-8 and SF-295, antifungal in Cladosporium cladosporioides and C. sphaerospermum, antibacterial using Staphylococcus aureus and Klebsiella pneumoniae, and mast cell degranulation inhibition using RBL-2H3 cells. The present work contributed for the secondary metabolism knowledge increase regarding Bostrychia tenella species, and demonstrated the endophytic microorganism biological potential, attributing to this species chemical and microbiological relevance for the marine natural products research.