Dissertations / Theses on the topic 'Glycerol system'

In 2014 SÖRAB constructed a continuous biological treatment system (KBR) to handle leachate waterfrom the landfill at the facility in Löt, north of Stockholm. The KBR is mainly focused on removal ofammonium nitrogen which would otherwise be released in to the recipient and contribute toeutrophication and damage to the environment. This project has focused on replacing the currentcarbon source in the process Brenntaplus VP1 and evaluating the efficiency of denitrification andeconomy of transitioning to a new carbon source. The carbon sources glycerol and ethanol wereevaluated and compared to Brenntaplus VP1 for the denitrification efficiency and microbial profile.The experiments were performed in laboratory conditions and in pilot scale using leachate water fromLöt. The reduction of ammonia was evaluated by chemical precipitation, addition of carbon sources bymeasuring ammonia-N and nitrate-N under aerobic (nitrification) and anaerobic (denitrification)conditions. The combination of ethanol and glycerol showed an enhanced denitrification and increasedmicrobial community both in lab and pilot scale studies with reduced hydraulic retention time. Therate of nitrate reduction was 0.23 mgNO3-N 1 -1 h -1 for ethanol/glycerol compared to 0.12-0.17mgNO 3- -N 1 -1 h -1 for Brenntaplus VP1 in pilot scale. The results indicate that using ethanol, glycerolor a mix of the two as a substitute for Brenntaplus VP1 is viable. This has been based on laboratoryand pilot scale studies. Each of the carbon sources examined during this project have showed a uniqueimpact on the process and its parameters such as: denitrification rate, microbial density and microbialcomposition. The carbon sources had an impact with temperature fluctuation and faster denitrificationcompared to the conventional KBR system. This implies that the carbon sources tested in this projectcan be advantageous and beneficial for Sörab depending on the carbon source availability and theseasonal variations.
Under 2014 konstruerade SÖRAB ett kontinuerligt biologiskt reningsverk (KBR) för att hanteralakvatten från deponin för ickefarligt avfall vid anläggningen i Löt, norr om Stockholm. KBR ärfrämst konstruerad för rening av ammoniumkväve som annars skulle släppas ut till recipienten ochbidra till övergödning och skador på miljön i området. Detta projekt har fokuserat på att ersätta dennuvarande kolkällan Brenntaplus VP1 som används i processen och utvärdera effektiviteten idenitrifieringen samt ekonomin vid övergång till en ny kolkälla. Kolkällorna glycerol och etanol varde kolkällor som valdes för utvärdering i detta projekt, dessa jämfördes med Brenntaplus VP1 i desseffekt på denitrifikationseffektivitet och mikrobiell sammansättning under laboratorieförhållanden ochi pilotskala. Möjligheten att reducera ammoniumkoncentrationen i lakvattnet utvärderades genomkemisk fällning och genom mätning av ammoniumkväve och nitratkväve under aeroba (nitrifikation)och anaeroba (denitrifikation) förhållanden. Kombinationen av etanol och glycerol indikerade enförbättrad denitrifikation och ökad mikrobiell densitet både i laboratorie- och pilotskala med reduceradhydraulisk retentionstid. Nitratreduktionshastigheten var 0,23 mgNO 3- -N 1 -1 h -1 för blandningen avetanol/glycerol jämfört med 0,12 - 0,17 mgNO 3- -N 1 -1 h -1 för Brenntaplus VP1 i pilotskala. Resultatenindikerar att användning av etanol, glycerol eller en blandning av de två har goda förutsättningar föratt ersätta Brenntaplus VP1. Var och en av de tre kolkällorna som undersöktes under detta projekt harvisat en unik inverkan på processen och dess parametrar såsom: denitrifikationshastighet, mikrobielldensitet och mikrobiell sammansättning. Genom att byta kolkälla i KBR kan prestandan ökas genomatt minska den hydrauliska retentionstiden samtidigt som systemet tycks bli mindre känsligt förtemperatursvängningar. Kolkällorna som utvärderats i detta projekt kan därför vara fördelaktiga för SÖRAB beroende på dess tillgänglighet och pris.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.
During biodiesel production, crude biodiesel and glycerin are separated in resting tanks due to gravity and differences in density, glycerin accumulates at the base of the contender; such operation is called decantation. The decantation stage, within the production of biodiesel based on recycled oil, takes from 8 to 24 h to complete. Therefore, the development of an automatic biodiesel decanting system is presented in order to optimize the production time in the line of this bio-fuel. The process consists of applying an electric field through two electrodes at 9 kV and simultaneously applying temperature. The results of the implementation showed that the production time was reduced by up to 99% without affecting the quality of biodiesel, according to the parameters of the American Society for Testing and Materials (ASTM).
Revisión por pares

Le travail présenté dans cette thèse porte sur la synthèse et les caractérisations thermiques et rhéologiques d'un nouveau type de nanofluide : le système Cu2O/Glycérol. La caractérisation est faite en fonction de la taille des particules mises en suspension, de la température et de la fraction volumique solide. Ce travail a nécessité la synthèse des nanoparticules et des nanofluides par la méthode de décomposition thermique des précuseurs organométalliques, qui présente un bon rendement en quantité de nanoparticules (17%). Et le montage d'un dispositif de caractérisation thermique utilisant la méthode 3ω. Finalement, nous avons passé à la caractérisation rhéologique et thermique de ces échantillons. Les résultats obtenus avec ce nouveau système sont intéressants, car l'augmentation de la conductivité thermique atteint des valeurs importantes : 120% et 35% respectivement pour des fractions volumiques aussi faibles que 0,625% et 0,078% de nanoparticules de 7 nm de diamètre, sans influence notable sur la viscosité du fluide hôte, permettant une bonne amélioration du bilan énergétique total. Nous avons observé que la concentration et la taille (surface) des nanoparticules sont des paramètres clefs du comportement de la conductivité thermique effective du nanofluide Cu2O/Glycérol. Nos mesures nous ont permis de déduire la prédominance des modifications de la surface des nanoparticules (par fonctionnalisation ou par réaction chimique secondaire) sur le mouvement brownien dans les transferts thermiques nanoparticules/ fluide hôte.

Dans cette étude, l’amélioration des propriétés physiques et de sa durabilité aux agents de dégradation biologique du hêtre européen (Fagus sylvatica) a été réalisée au moyen de différents traitements. Les premiers types de traitements sont basés sur l'imprégnation de dérivés vinyliques de glycérol ou de polyglycérol en tant qu'additif suivi d’une étape de modification thermique réalisée dans un réacteur ouvert (OHT) ou fermé (HPS). Le deuxième type de traitement repose sur la poly-estérification in situ du sorbitol et de l'acide citrique à différentes concentrations et températures de durcissement en système ouvert. Diverses propriétés de durabilité physique, chimique, mécanique et biologique des bois modifiés ont été évaluées. Les résultats montrent que certains traitements peuvent améliorer de manière significative les propriétés de durabilité physique et biologique du bois contre les agents de pourriture blanche, brune et molle et surtout vis-à-vis de l’attaque des termites comparativement au bois non traité ou modifié thermiquement uniquement
In this study, improvement of physical and biological durability properties of European beech (Fagus sylvatica) has been performed through different bulking impregnation treatments. The first modification was based on the impregnation of vinylic derivatives of glycerol or polyglycerol as additive followed with different thermal modification conditions in the opened system (OHT) or in the closed system (HPS). The second modification was based on the in-situ polyesterification of sorbitol and citric acid at different concentrations and curing temperatures in the opened system. Various physical, chemical, mechanical, and biological durability properties of the modified woods were evaluated, including certain properties during modification. The results have disclosed that certain treatments can improve significantly physical and biological durability properties of wood against decay (white rot, brown rot, and soft rot fungi) and termites attacks in comparison to untreated wood or thermally modified woods

There is conflicting information on the mechanical properties and ageing kinetics of starch-water-glycerol systems. This makes understanding the changes occurring on storage of edible products difficult to predict. The work described in this thesis looks at model systems consisting of thermomechanically extruded plasticized starches (waxy maize, rice and wheat) and commercial products. The objectives of the work were to evaluate how the presence of polyols effects glass transition temperature (Tg), sorption isotherms, diffusion rates and texture parameters and to create models that could be used to predict behaviour. Very similar results were obtained for the starch samples except that monolayer (ma) values were higher for the waxy maize starch than for the wheat and rice. The waxy maize also was more brittle at equivalent moisture content when compared to the other two starches. Glycerol had a major impact on the water absorption. For RHs > 70% more water absorbed up by samples containing glycerol while the opposite occurred at RHs <60%. Monolayer values for GAB and BET confirmed this finding. The behaviour could be predicted if an interaction factor <1 was used in weight fraction models. Tg of the samples was measured by DSC and also by using predictive models, where the ten-Brinke Karas equation was found to give the best predictions. A value that was found to be most beneficial for the prediction of retrogradation was (storage temperature minus Tg). Change in texture was associate with (T-Tg), although the brittle ductile transition occurred 40°C below T-Tg=O. Diffusivity values increased with plasticizer level up to 8*10 3 m'z/s. There was an apparent fall in values when the samples were above Tg. However, it is suggested that this is due to sample geometry change rather than a change in diffusion mechanism. The Tg values also were found to be a good predictor of the type of change occurring in the model systems and food products during storage. Below Tg physical aging (enthalpy relaxtion) could be seen in the samples and retrogradation of the starch occurred above Tg. The rates of retrogradation were not affected by glycerol content directly and knowledge of Tg and storage temperature were sufficient to predict the retrogradation. Products became stiffer on storage and this was associated with molecular reassociation of the starchy component, but control of the moisture was also critical as water still dominated product behaviour even in the presence of glycerol.

Cada día se usan grandes cantidades de disolvente para diferentes aplicaciones industriales. La búsqueda de nuevos disolventes que sean menos dañinos para el medio ambiente, biodegradables y menos tóxicos, con el fin de reemplazar los disolventes orgánicos convencionales, se ha convertido en un área de investigación importante, especialmente cuando estos disolventes se pueden reutilizar sin necesidad de reacondicionamiento. En este sentido, los disolventes procedentes de la biomasa se han convertido en una solución prometedora. En especial, el glicerol, producido hoy en día en grandes cantidades en las industrias de biodiesel, se presenta como un buen candidato. Sus características, tales como su bajo coste, su baja toxicidad, su alto punto de ebullición y su selectiva miscibilidad y solubilidad con compuestos orgánicos hacen que sea un disolvente interesante para su uso en catálisis. Esta Tesis trata sobre el desarrollo de nuevos sistemas catalíticos adaptados para el uso de glicerol como disolvente. En particular, en este trabajo demostramos cómo el glicerol puede facilitar la estabilización de nanopartículas de cobre(I) capaces de catalizar la cicloadición 1,3-dipolar de Huisgen entre alquinos terminales y azidas orgánicas (conocida como reacción click). Además, esta reacción puede llevarse a cabo también en ausencia de metal usando alquinos internos, esta vez trabajando con radiación microondas con otros disolventes (incluyendo próticos), probablemente por su habilidad para formar enlaces de hidrógeno, lo que favorece la interacción con la radiación de microondas acelerando el proceso. Con el objetivo de estudiar procesos estereoselectivos en este medio, hemos sintetizado por primera vez nuevos derivados de PTA (1,3,5-triaza-7- fosfaadamantano) enantiopuros y hemos estudiado su actividad en diferentes reacciones catalíticas asimétricas de interés.
Cada dia s’empren grans quantitats de dissolvent per a diferents aplicacions industrials. La recerca de nous dissolvents que siguin menys nocius per al medi ambient, biodegradables i menys tòxics, per tal de substituir els dissolvents orgànics convencionals, s'ha convertit en una àrea d'investigació important, especialment quan aquests dissolvents es poden reutilitzar sense necessitat de reacondicionament. En aquest sentit, els dissolvents procedents de la biomassa han esdevingut una solució prometedora. En particular, el glicerol, produït avui dia en grans quantitats en les indústries de biodièsel, es presenta com un bon candidat. Les seves característiques, com ara el seu baix cost, la seva baixa toxicitat, el seu alt punt d'ebullició i la seva miscibilitat i solubilitat selectiva envers compostos orgànics fan que sigui un dissolvent interessant per al seu ús en catàlisi. Aquesta Tesi tracta sobre el desenvolupament de nous sistemes catalítics adaptats per a l'ús de glicerol com a dissolvent. En particular, en aquest treball demostrem com el glicerol pot facilitar l'estabilització de nanopartícules de coure (I) capaces de catalitzar la cicloaddició 1,3-dipolar de Huisgen entre alquins terminals i azides orgàniques (coneguda com reacció click). A més, aquesta reacció es pot dur a terme també en absència de metall usant alquins interns, aquest cop treballant amb radiació de microones altres dissolvents (incloent-hi pròtics), probablement per la seva habilitat per formar enllaços d'hidrogen, fet que afavoreix la interacció amb la radiació de microones, tot accelerant el procés. Amb l'objectiu d'estudiar processos estereoselectius en aquest medi, hem sintetitzat per primera vegada nous derivats de PTA (1,3,5-triaza-7- fosfaadamantà) enantiopurs i hem estudiat la seva activitat en diferents reaccions catalítiques asimètriques d'interès
Solvents are needed in large scale for different industrial applications. The search for less harmful, biodegradable, non-toxic green alternatives able to replace conventional organic solvents is an active area of research, especially when these solvents can be reused without the need of reconditioning treatments. In this sense, solvents derived from biomass are emerging as very promising solutions. Glycerol, produced in high amounts as a side product in biodiesel production, represents a good candidate. Due to its low cost, low toxicity, high boiling point and selective solubility and miscibility with organic compounds, glycerol represents a good choice to be applied in chemical transformations, including catalytic ones. This Thesis deals with the development of new catalytic systems in glycerol medium. In particular, in this work we show how glycerol can facilitate the stabilization of copper(I) nanoparticles that are able to catalyze the 1,3-dipolar Huisgen cycloaddition between terminal alkynes and organic azides (known as click reaction). Moreover, this reaction can be carried out in the absence of copper using internal alkynes, working under microwave irradiation. Glycerol favours the process in comparison with other solvents (including protic ones), probably due to its ability to form hydrogen bonds, which favors the interaction with microwave irradiation (accelerating the process).

La grande quantité des solvants utilisés dans l'industrie chimique représente un des problèmes les plus importants à aborder, d'un point de vue environnemental ainsi qu'économique. Les solvants communément utilisés sont volatiles, toxiques, inflammables et/ou corrosifs, et leur substitution par des autres moins nocifs est un objectif primordiale dans un cadre de développement durable. Le glycérol se présente comme un candidat prometteur pour remplacer les solvants organiques conventionnels. Il est généré comme produit concomitant dans la production de biodiesel. En conséquence, la valorisation du glycérol est devenue un enjeu majeur. Ce composé possède des propriétés très intéressantes pour être utilisé comme solvant en catalyse, telles que son innocuité, haut point d'ébullition, pression de vapeur négligeable, capacité de solubilisation de composés organiques et inorganiques, faible miscibilité avec autres solvants organiques et également son faible coût. Cette Thèse à pour objectif développer des nouveaux systèmes catalytiques dans un milieu glycérol. En particulier, dans ce travail nous montrons comme le glycérol promue la stabilisation de nanoparticules de cuivre (I) capables de catalyser la réaction de Huisgen 1,3-dipolaire entre alcynes terminaux et azotures organiques (connu comme la réaction click), de façon très efficace à température ambiante. Dans ce solvant, cette réaction peut aussi être réalisée en absence de cuivre avec alcynes internes non activés, en travaillant sous activation microondes. L'utilisation du glycérol favorise la réaction par rapport à des autres solvants (incluant ceux qui sont protiques), probablement grâce à sa capacité pour former liaisons d'hydrogène, favorisant l'interaction avec l'irradiation microondes (et ainsi accélérant la réaction). Avec le propos d'étudier des transformations stéréosélectives, nous avons préparé des nouveaux ligands énantiopures dérivés du PTA (1,3,5-triaza-7-phosphaadamantane). Ces composés innovants ont été utilisés en réactions énantiosélectives comme l'addition asymétrique de B2pin2 à N-Boc-imines (Cu) ou encore la alpha-amination (Cu), ou encore comme organocatalyseur (réaction de Morita-Baylis- Hillman)
Solvents are used in huge amounts in the chemical industry and this is one of the biggest problems to be solved not only from an environmental point of view, but also for economic reasons. The solvents commonly used in the industry are volatile, toxic, inflammable and/or corrosive; then, their replacement by others less harmful represents a crucial objective. Glycerol appears as a promising candidate to substitute the conventional organic solvents. It is produced in huge amounts as a waste in biodiesel industry. Consequently, the valorisation of glycerol becomes an important concern. This compound possesses very interesting properties to be used as solvent such as its non-toxicity, the wide range of temperature for its liquid state, negligible vapour pressure, capacity for solubilising organic and inorganic compounds, low miscibility with other organic solvents and also its low price. This Thesis deals with the development of new catalytic systems in glycerol medium. In particular, in this work we show how glycerol can facilitate the stabilisation of copper(I) nanoparticles that are able to catalyse the 1,3-dipolar Huisgen cycloaddition between terminal alkynes and organic azides (known as click reaction). The reaction proceeds at room temperature and it is very efficient. Moreover, this reaction can be carried out in the absence of copper using non-activated internal alkynes, working under microwave irradiation. Glycerol favours the process in comparison with other solvents (including protic ones), probably due to its ability to form hydrogen bonds, which favours the interaction with the microwave irradiation (accelerating the process). With the aim of studying stereoselective transformations, we have conceived new enantiopure ligands derived from PTA (1,3,5-triaza-7-phosphaadamantane). These innovative phosphines have been applied in enantioselective processes, such as pinacolboryl addition to N-Boc-imines (Cu) or alpha-amination (Cu), among others, or as organocatalyst (Morita-Baylis-Hillman reaction)

Systemic acquired resistance (SAR) is a type of plant defense mechanism that is induced after a localized infection and confers broad-spectrum immunity against related or unrelated pathogens. During SAR, a number of chemical signals and proteins generated at the site of primary infection travel to the uninfected tissues and are thought to alert the distal sites against secondary infections. Glycerol-3-phosphate (G3P) is one of the chemical signals that play an important role in SAR. G3P is synthesized in the cytosol and chloroplasts via the enzymatic activities of G3P Dehydrogenase (G3Pdh) or Glycerol Kinase (GK). Interestingly, a mutation in three of the five G3Pdh isoforms or GK impairs SAR by lowering the pathogen induced G3P pool. This suggests that total cellular pool of G3P is critical for SAR. To determine factors contributing to G3P flux between various subcellular compartments I analyzed the role of putative G3P transporters in G3P flux and SAR. The Arabidopsis genome encodes five isoforms of G3P Permeases (G3Pp) and these transmembrane proteins are predicted to localize to plasma membrane, chloroplast or mitochondria. At least two G3Pp isoforms (G3Pp1 and G3Pp3) were able to complement the Escherichia coli mutant impaired in the uptake of G3P into the cytoplasm. Characterization of Arabidopsis G3Pp mutants showed that a mutation in G3Pp2, G3Pp3 and G3Pp4 compromised SAR but not local resistance. Furthermore, this SAR defect could only be complemented by exogenous application of G3P. The G3Pp mutants accumulated wild-type-like levels of G3P suggesting that the subcellular compartmentalization of G3P might contribute to the induction of SAR.

This thesis is focused on proposition of non-freezing heat transfer fluid. Fluid will be based on mixture of propane-1,2,3-triol with water and modern corrosion inhibitors. Then will be investigate, if this new compound is competetive to common used liquids like ethylene glycol or propylene glycol.

Plants use several strategies to defend themselves against microbial pathogens. These include basal resistance, which is induced in response to pathogen encoded effector proteins, and resistance (R) protein-mediated resistance that is activated upon direct or indirect recognition of pathogen encoded avirulence protein(s). The activation of Rmediated signaling is often associated with generation of a signal, which, upon its translocation to the distal uninfected parts, confers broad-spectrum immunity against related or unrelated pathogens. This phenomenon known as systemic acquired resistance (SAR) is one of the well-established forms of induced defense response. However, the molecular mechanism underlying SAR remains largely unknown. Induction of plant defense is often associated with a fitness cost, likely because it involves reprogramming of the energy-providing metabolic pathways. Glycerol metabolism is one such pathway that feeds into primary metabolism, including lipid biosynthesis. In this study, I evaluated the role of glycerol-3-phosphate (G3P) in host-pathogen interaction. Inoculation with the hemibiotrophic fungal pathogen Colletotrichum higginsianum led to increased accumulation of G3P in wild-type plants. Mutants impaired in biosynthesis of G3P showed enhanced susceptibility, suggesting a correlation between G3P levels and basal defense. Conversely, increased biosynthesis of G3P correlated with enhanced resistance. The Arabidopsis genome encodes one copy of glycerol kinase (GK), which catalyzes phosphorylation of glycerol to G3P, and five copies of G3P dehydrogenase (G3Pdh), which catalyze reduction of dihydroxyacetone phosphate to G3P. Analysis of plants mutated in various G3Pdh's showed that plastidal lipid biosynthesis was only dependent on the GLY1 isoform but the pathogen induced G3P pool required the function of GLY1 and two other G3Pdh isoforms. Interestingly, compromised G3P biosynthesis in GK and G3Pdh mutants also compromised SAR, which was restored when G3P was provided exogenously. Detailed biochemical analysis showed that G3P was transported to distal tissues and that this process was dependent on a lipid transfer protein, DIR1. Together, these results show that G3P plays an important role in both basal- and induced-defense responses.

This work investigates polyols – glycerol and sucrose – as an alternative ligand for electroless copper plating systems with reducer formaldehyde. Natural polyols are environmentally friendly, easily bio-degradable materials, but has not been studied enough for suitability for copper plating systems. In order to increase of the efficiency, the electroless copper plating was investigated in ultrasonic milieu to observe how ultrasound impacts the copper plating rate and properties of the obtained coatings. Studies have shown that sucrose and glycerol can be used as ligands in solutions for electroless copper plating. A plating rate of copper under optimum conditions can reach 2.2 m h-1 (sucrose) and 3.4 m h-1 (glycerol) and copper surface roughness factors ranging 8.5 - 25.3 (sucrose) and 2,3 - 4.3 (glycerol). Correlations between dependences on pH observed for copper plating speeds, overpotentials, surface roughness factors, anodic oxidation currents of formaldehyde. A use of ultrasound for electroless copper plating systems change speeds. Depending on the choice of copper plating system and ultrasonic frequency, plating rate can decrease or may increase up to 5 times and can reach high values (10.87 m h-1). The copper surface formed in ultrasound environment more compact, smoother.
Šiame darbe tiriami polihidroksiliai alkoholiai sacharozė bei glicerolis, kaip ligandų alternatyvos cheminio variavimo sistemoms su reduktoriumi formaldehidu. Tai yra ekologiškos, biologiškai lengvai suyrančios medžiagos. Šiame darbe atlikti šių medžiagų kompleksų pusiausvyros skaičiavimai, eksperimentai parodantys sacharozės bei glicerolio praktinį pritaikomumą cheminio variavimo sistemose. Ultragarso poveikio cheminėms sistemoms dėsningumai dar nėra vienareikšmiškai ištirti ir suprasti. Siekiant padaryti cheminį metalų nusodinimą efektyvesniu pastaruoju metu cheminio metalizavimo procesams bandoma taikyti ultragarsą. Atlikti tyrimai parodė, kad naudojant sacharozę ir glicerolį ligandais cheminio variavimo tirpaluose vario nusėdimo greitis optimaliomis sąlygomis siekia atitinkamai 2,2 ir 3,4 m/h, o chemiškai nusodinto vario paviršiaus šiurkštumo faktoriai varijuoja 8,5-25,3 ir 2,3-4,3 ribose. Analizuojant gautus duomenis stebimos koreliacijos tarp vario nusėdimo greičio, viršįtampio, paviršiaus šiurkštumo faktoriaus, formaldehido anodinės oksidacijos srovių maksimumų priklausomybių nuo pH. Ultragarso panaudojimas cheminio variavimo sistemose keičia vario nusėdimo greičius. Priklausomai nuo pasirinktos cheminio variavimo sistemos, ultragarso dažnio ar jo skleidimo būdo vario nusėdimo greitis sumažėja iki visiško proceso sustabdymo arba gali padidėti 2-5 kartus ir pasiekti dideles vertes (10,87 μm/h). Ultragarso aplinkoje dažniausiai susiformuoja kompaktiškesnės, lygesnės... [toliau žr. visą tekstą]

Thesis (Ph. D.)--Illinois State University, 1993.
Title from title page screen, viewed February 14, 2006. Dissertation Committee: Robert L. Preston (chair), George W. Kidder, Jim Tone, John Frehn, Wayne Riddle. Includes bibliographical references (leaves 144-150) and abstract. Also available in print.

The conserved metabolites, oleic acid (18:1), a major monounsaturated fatty acid (FA), and glycerol-3-phosphate (G3P) are obligatory precursors of glycerolipid biosynthesis in plants. In Arabidopsis, the SSI2-encoded SACPD is the major isoform that contributes to 18:1 biosynthesis. Signaling induced upon reduction in oleic acid (18:1) levels not only upregulates salicylic acid (SA)-mediated responses but also inhibits jasmonic acid (JA)- inducible defenses. I examined the transcription profile of ssi2 plants and identified two transcription factors, WRKY50 and WRKY51. Although the ssi2 wrky50 and ssi2 wrky51 plants were constitutively upregulated in SA-derived signaling, they were restored in JAdependent defense signaling. Not only did these plants show JA-inducible PDF1.2 expression, but they were also restored for basal resistance to the necrotrophic pathogen, Botrytis cinerea. Overall, my results show that the WRKY50 and WRKY51 proteins mediate both SA- and low 18:1-dependent repression of JA signaling in Arabidopsis plants. My studies also show that cellular G3P levels are important for plant defense to necrotrophic pathogens. I showed that G3P levels are induced in Arabidopsis in response to the necrotrophic fungal pathogen B. cinerea. G3P-dependant induction of basal defense is not via the activities of other defense-related hormones such as SA, JA or the phytoalexin camalexin. Arabidopsis mutants unable to accumulate G3P (gly1, gli1) showed enhanced susceptibility to B. cinerea. Previous studies in our lab identified acyl-carrier protein 4 (ACP4), a component of FA and lipid biosynthesis, as an important regulator of plant systemic immunity. ACP4 mutant plants were defective in systemic acquired resistance (SAR) because they contained a defective cuticle. I further investigated the role of the plant cuticle in SAR by studying the involvement of long-chain acyl-CoA synthetases (LACS), a gene family involved in long-chain FA and cuticle biosynthesis, in SAR. In all, eight lacs mutants (lacs1, lacs2, lacs3, lacs4, lacs6, lacs7, lacs8, lacs9) were isolated and characterized. Six mutants were compromised in SAR. Together, my studies show that the various LACS isoforms contribute differentially to both cuticle formation and systemic immunity in Arabidopsis.

Le processus oscillatoire observe au debut du plateau d'electrodissolution (region controlee par le transport de masse) dans le systeme fe/h 2so 4 1m a ete etudie en considerant les parametres suivants : l'addition de glycerol afin de modifier la viscosite de la solution, la presence d'ions chlorure et la geometrie de l'ecoulement (electrode a disque tournant, electrode a cylindre tournant et electrode a jet noye). Les caracteristiques des oscillations ont ete deduites de l'analyse des densites spectrales de puissance (dsp) obtenues a partir des enregistrements temporels du courant et de la resistance d'electrolyte. Les resultats de ces mesures ont montre que les differents ecoulements hydrodynamiques, correspondants aux differentes geometries d'electrodes utilisees, n'exercent aucune influence sur les caracteristiques des oscillations qui apparaissent et disparaissent a des potentiels distincts suivant l'ordre : periodique, aperiodique, periodique. On a observe que l'aperiodicite augmente avec la vitesse de rotation et que l'augmentation de la viscosite de la solution, resultant de l'addition de glycerol, conduit a l'apparition d'oscillations periodiques sur tout le domaine non-stationnaire. Quand la concentration en chlorure est superieure a 0,005 m, les oscillations presentent une composante non-lineaire dans un domaine de potentiel distinct qui peut etre due a l'action chimique agressive des ions chlorure a l'interface. On a observe aussi la disparition du domaine non-stationnaire pour deux situations : pour les faibles vitesses de rotation de l'electrode tournante avec une viscosite de l'electrolyte elevee et pour une concentration de chlorure comprise entre 0,0075 et 0,015 m. Le comportement de la valeur moyenne de la resistance d'electrolyte en fonction du potentiel est similaire dans tous les cas etudies : la resistance d'electrolyte augmente de facon monotone avec le potentiel jusqu'a une valeur maximale dans la region oscillatoire. Ces resultats suggerent que le processus oscillatoire est lie a la formation d'especes colloidales au voisinage de l'interface electrode/electrolyte. Celles-ci sont responsables de la diminution de la conductivite dans cette region et de l'augmentation des gradients de viscosite.

Systemic acquired resistance (SAR) is a form of inducible defense response triggered upon localized infection that confers broad-spectrum disease resistance against secondary infections. Several factors are known to regulate SAR and these include phenolic phytohormone salicylic acid (SA), phosphorylated sugar glycerol-3-phosphate (G3P), and dicarboxylic acid azelaic acid (AzA). This study evaluated a role for free radicals nitric oxide (NO) and reactive oxygen species (ROS) in SAR. Normal accumulation of both NO and ROS was required for normal SAR and mutations preventing NO/ROS accumulation and/or biosynthesis compromised SAR. A role for NO and ROS was further established using pharmacological approaches. Notably, both NO and ROS conferred SAR in a concentration dependent manner. This was further established using genetic mutants that accumulated high levels of NO. NO/ROS acted upstream of G3P and in parallel to SA. Collectively, these results suggest that NO and ROS are essential components of the SAR pathway.

This diploma thesis is focused on the evaluation of changes in non-freezing heat transfer liquid composed of mixture of polyols and water, used in the real solar thermic system. On the base of the research a new heat transfer liquid is proposed on the platform of 1,3-polyols. The emphasis is put on the non-toxic properties of such system revealing the two chemical candidates for a new heat transfer liquid: 1,3-propanediol and glycerol. These chemicals are mixed together with water using different volume concentrations and properties of such liquids are evaluated.

This thesis deals with the evaluation of changes in properties of an antifreeze heat transfer fluid based on polyols used in real solar thermal system. Emphasis is placed on the use of substances with low impact on the environment.

Les milieux réactionnels issus de l’étude de la réactivité de deux types de polyols, le glycérol et le diglycérol par réaction d’estérification directe avec l’acide undécylénique, catalysée par l’acide dodécylbenzène sulfonique (ADBS). Les résultats montrent que les ystèmes polyol/acide undécylénique donnent une émulsion eau dans huile (E/H). L’ajout de l’ADBS et de l’eau formée in-situ aux systèmes polyol/acide undécylénique ont permis de réduire la taille des gouttelettes de 50 μm à moins de 1 μm et d’obtenir un système organisé (micro-réacteur). L’augmentation de la température contribue à favoriser le transfert de matière dans les systèmes émulsionnés et / ou gélifiés et d’obtenir un système monophasique, homogène et structurés. L’étude de la réaction de ces systèmes avec une approche site à site (site OH / site COOH) a montré que lorsque le nombre de sites acides carboxyliques est inférieur à celui des sites hydroxyles, la synthèse est totalement sélective en esters partiels des deux polyols (glycérol et diglycérol). Les rendements sont supérieurs respectivement à 60% en esters partiels de glycérol et à 70% en esters partiels de diglycérol. La modélisation de la cinétique de synthèses et la régression des données cinétiques ont montré que la réaction est réversible d’ordre 2 et athermique. Les énergies d’activation calculées sont de 17 kcal/mol et 16 kcal/mol respectivement pour le monoundécénoate de glycérol (MUG) et le diundécénoate de glycérol (DUG). De plus, la méthodologie de recherche expérimentale a montrée que les variables (concentration en catalyseur ADBS et température) permettent d’obtenir le MUG avec un rendement de plus de 60% et une sélectivité en MUG de 80%. Ensuite, l’étude de la réactivité de la double liaison terminale du MUG en présence de deux agents oxydants pour engendrer des molécules bolaamphiphiles simples a été réalisée par H2O2 / acide formique et acide métachloroperbenzoïque (m-CPBA). Les résultats ont montré le 10,11-dihydroxy-monoundécénoate de glycérol (MUGDiol) est obtenu par oxydation au H2O2 / acide formique et le 10,11-époxy-monoundécénoate de glycérol (MUGE) par réaction d’époxydation avec la m-CPBA. L’ouverture de la fonction époxyde par des molécules aminées permet l’observation de nouvelles molécules bolaamphiphiles : le 10-hydroxy-N-11-((2-hydroxyéthyl)amino)monoundécénoate de glycérol(bola éthanolamineglycérol) et le N,N-11-(diaminobutan)-10-hydroxymonoundecanoate de glycérol (bola diaminobutaneglycérol). L’étude des propriétés physico-chimiques de ces molécules amphiphiles et bolaamphiphiles a permis de monter que toutes ces molécules sont de solvo-surfactants actifs aux interfaces et elles réduisent la tension interfaciale de l’eau jusqu’à la limite de la solubilité dans l’eau. L’adsorption des molécules ne vérifie pas le modèle de Gibbs. Le MUG et le MUDG s’auto-assemblent dans l’eau et donnent des nano-objets (vésicules et agrégats plats) et s’adsorbent sur des surfaces polaires et solides (silice et ciment). Ces deux molécules retiennent 30% et 56% molécules d’eau et le nombre de molécules d’eau fortement liée aux têtes polaires est de 21 et 49 respectivement pour le MUG et le MUDG. Pour es molécules bolaamphiphiles pures (MUGE et bola éthanolamineglycérol), elles retiennent plus de 56% de molécules d’eau et se lient à plus 53 molécules d’eau. L’ensemble de ces propriétés physico-chimiques a permis de répondre aux problématiques industrielles et de formuler un produit de cure, un agent de démoulage et un produit anti-adhérent.

This diploma thesis deals with the evaluation of changes in properties of an antifreeze heat transfer liquids based on glycols used in real solar thermal system. Emphasis is placed on the use of non-toxic substances, which include propane-1,3-diol.

This thesis develops composition of heat transfer fluids with antifreeze properties next to traditional one component glycols produced from propene and ethene. Based on assessment of physical properties it considers application of progressive antifreeze compounds of glycerine and propan-1,3-diole and their mixtures with classic glycols, which do not have negative influence on the environment and which are produced in last years from renewable sources. Due to the necessity of selection of certain compromise between their heat transfer properties, price, solubility and other factors physical properties of selected mixtures are determined together with synergy of each compound, including formulas with glycols: ethan 1,2 diol and propan 1,2 diol Another evaluated factor of studied formulations in addition to their heat transfer properties was anticorrosive protection of common corrosion inhibitors mixtures. The result of whole work is the proposal of several most perspective formulations based on mixtures of polyhydric alcohols in terms of their features enabling them heat transfer, reasonable costs, and the restrictions of impact of their use, particularly in heat transfer systems, to human health and the environment. The knowledge of physical properties of water solutions of polyhydric alcohols mixtures also helps to better using of recycled materials from planning recycling plant for glycols.

Future changes in the incidence and prevalence of OA are difficult to predict. As incidence and prevalence rise with increasing age, extending life expectancy will result in greater numbers with OA. Actually, usual therapeutic approaches are really restricted because of important side effects with long-term use. Therefore, there is a need to develop improved formulations which are well tolerated, biocompatible and biodegradable. Ideally, these new treatments should be able to deliver locally sufficient amount of anti-inflammatory or analgesic drugs into the site of arthritic inflammation while stabilizing or better restoring the mechanical integrity of the joint. In this way, the objective of this project is to develop slow-release gels that are sterile, injectable, characterized by viscoelastic properties and capable to sustain the in situ release of both hydrophilic and lipophilic drugs. The intraarticular delivery combined to sustained-release property should be interesting to reduce the number of injection required while prolonging the local drug activity over weeks. For that purpose, glycerol monooleate (GMO), also called “monolein” was selected for its capacity to form highly viscous crystalline phase structures upon contact with an aqueous fluid (e.g. synovial fluid).

In the first step of this work, it was decided to develop and characterize hydro-lipidic gels based on the use of monolein and hyaluronic acid in order to provide in vitro sustained release of hydrophilic drugs such as clonidine and lipophilic drugs such as betamethasone. Initially, a compatibility study was performed on the main ingredients selected in order to check that there were not physico-chemical incompatibilities, which could be deleterious regarding to their stability in formulation. Then, the development of hydro-lipidic gels was initiated by considering on the first hand the solubility of each ingredient and on the other hand the syringeability, the rheological properties and the in vitro dissolution profiles obtained for the developed formulations. The objective of this preformulation program was to identify potential candidates that presented suitable syringeability while being able to sustain the release of drugs over weeks and being characterized by interesting viscoelastic properties for the long-term management of osteoarthritis. Moreover, several methods of quantification and characterization were developed in order to allow the physico-chemical properties (rheology, syringeability, water uptake, stability and dissolution profiles) of the developed formulations to be studied.

Results of the compatibility study showed that the concomitant use of monolein, hyaluronic acid and clonidine/betamethasone is not contraindicated. Next, the preformulation program allowed many injectable drug delivery systems to be prepared. However, the carrier that best meets our needs was composed of 10,0 % (wt/wt) absolute ethanol ;15,0 % propylene glycol (wt/wt) ;15,0 % (wt/wt) water ;55,0 % (wt/wt) de monolein ;5,0 % (wt/wt) purified soybean oil ;0,03 % (wt/wt) α-tocophérol and 7,5 mg/g sodium hyaluronate (1.9 MDa). This carrier assured suitable syringeability and rheological properties. Indeed, it presented marked pseudoplastic flow behavior that allowed relatively fast injection through a narrow needle, followed by an increase in viscosity upon contact with aqueous fluids to obtain an in vitro sustained release of hydrophilic and lipophilic drugs over a few weeks. As a consequence, it was assumed that this carrier should be able to jellify in situ upon contact with physiological fluid such as synovial fluid. Then, according to EMA recommendations, a fast and easy manufacturing process that could be applied in a cleanroom at industrial scale was validated in our Laboratory. Finally, according to these promising results obtained in vitro, a stability study was performed on the carrier alone and containing clonidine or betamethasone according to ICH recommendations described for products intended for storage in a refrigerator. In that purpose, several parameters such as the quantification of drugs, the pH, the molecular weight of hyaluronic acid, the dissolution profiles of drugs and the rheological properties of the formulations were recorded depending on time and conditions of storage. This stability study showed clearly the importance to adjust the pH value of the formulation. Indeed, it was demonstrated that a pH value of 6.5, adjusted with diluted NaOH, allowed the stability of the formulation to be significantly improved. During this first step of this project, our Laboratory initiated two new collaborations. On the first hand, collaboration with the Laboratory of Professor Siepmann (University of Lille 2 – Faculty of Pharmacy) was started for their expertise on mathematical modeling. On the other hand, collaboration with the Laboratory of Professor Jerôme (ULg – Faculty of sciences) was started for their expertise on macromolecular chemistry and more particularly on rheological properties.

In the second step of this work, it was decided to evaluate in vitro the safety and the efficiency of the developed carrier and formulations containing clonidine or betamethasone. In this way, it was suggested to test selected drugs and potential candidates formulations on equine polymorphonuclear leukocytes (PMN) by measuring the production of reactive oxygen species (ROS) by PMNs stimulated or not with phorbol 12-myristate 13-acetate (PMA). For that purpose, our Laboratory initiated a new collaboration with the Laboratory of Professor Serteyn (ULg – Faculty of veterinary) for their expertise on equine PMNs and quantification of (ROS) produced in particular in inflammatory diseases.

This in vitro study has shown that no pro-inflammatory effect appeared by incubating carrier with unstimulated PMNs in comparison with the control assay. However, the production of ROS was quickly and considerably decreased when stimulated cells were placed in contact with carrier regardless on the incorporation of clonidine or betamethasone. This observation demonstrated that developed carrier provided a strong antioxidant effect, certainly by trapping the ROS produced. These results were very promising because that antioxidant effect of carrier could inhibit oxidative damages and might consequently potentiate the prevention of inflammatory conditions. Concerning the clonidine and betamethasone, only the last one provided significant inhibition of the ROS activity.

Finally, by considering the very promising results obtained with the in vitro study on PMNs, an in vivo study on rabbits, which seemed to be the most appropriate small animal model for this kind of intraarticular formulations, was performed to evaluate the toxicity and the efficiency of the developed carrier and formulation containing betamethasone. Therefore, our Laboratory started collaboration with the unit of research in osteo-articular pathologies (UROC) of Pr. Henrotin (ULg) for their expertise in animal models, in particular rabbits with osteoarticular pathologies such as osteoarthritis. For this purpose, this in vivo study was outsourced by TNO (Delft, Holland) and was designed as follow: (i) 0.9 % saline buffered (n=8); (ii) carrier (n=8); (iii) formulation containing betamethasone (n=8); (iv) Durolane® (n=8) a marketed product of HA. Surprisingly, it seemed that the control group (saline buffered) presented macroscopical and histological scores that were globally low according to literature. As a consequence, it was difficult to conclude about the efficiency of the developed treatments by considering only this pilot study. However, it is important to note that it seemed that the expected viscoelastic protection of the carrier to prevent the degradation of articular cartilage was not optimal regardless on the incorporation of betamethasone. Nevertheless, the histological analyses of synovial membranes from each treated groups demonstrated that there was no pro-inflammatory reaction. This meant that all formulations tested were well tolerated despite of the apparition of lumps (in 37.5 % of treated rabbits) that are probably due to both the high volume injected (900 µL) and an excessive and unexpected in situ water uptake of developed formulations based on GMO. However, this lack of rejection of the developed carrier could be very important since it allowed new perspectives to be considered. For example, other articular disorders could be targeted by incorporating drugs, for which in situ sustained release or mechanical protection could be beneficial.

Our laboratory is member of a collaborative project "JOINT-AIC" from BioWin and is supported by a grant from the Walloon Region. The development of analytical methods, the evaluation of physico-chemical properties and finally the preparation of sterile batches of formulations based on GMO intended for in vitro and in vivo studies were performed in the Laboratory of Galenic and Biopharmacy of the Faculty of Pharmacy of ULB./L’arthrose est une pathologie dont la prévalence et le coût ne font qu’augmenter dans notre société vieillissante. Les moyens thérapeutiques actuels étant fort limités suite à de sérieux effets secondaires à long terme, il existe réellement un besoin médical important de développer de nouveaux traitements locaux qui soient bien tolérés, biocompatibles et biodégradables. Idéalement, ceux-ci devraient être actifs au niveau du processus inflammatoire ou de la douleur tout en étant capable de stabiliser, voire de restaurer, l’intégrité mécanique de l’articulation.

Dans cette optique, l’objectif de ce projet a été de développer des systèmes hydrolipidiques stériles, injectables et viscoélastiques qui soient capables de prolonger in situ la libération de principes actifs hydrophiles et lipophiles. Cette caractéristique devait permettre de réduire le nombre d’injections nécessaires dans le cadre du traitement symptomatique de l’arthrose et de maintenir l’effet des composés sur un minimum de quatre à six semaines. Cette étude entre dans le cadre du projet JOINT-AIC entièrement financé par le programme BioWin de la Région Wallonne. Le développement, la validation des méthodes analytiques, l’évaluation des propriétés physico-chimiques ainsi que la préparation stérile des lots de formulation destinés aux tests in vitro et in vivo ont été réalisés au sein du Laboratoire de Galénique et Biopharmacie de la Faculté de Pharmacie de l’ULB.

Au cours de ce projet, il a donc fallu dans un premier temps développer et caractériser des formulations hydrolipidiques à base de monoléine et d’acide hyaluronique permettant une libération in vitro prolongée de principes actifs tels que la clonidine (hydrophile) et le dipropionate de bétaméthasone (lipophile). Une étude de compatibilité a ainsi été préalablement réalisée afin de s’assurer qu’aucun des constituants principaux de la formulation ne présentaient d’incompatibilité physico-chimique qui pourrait être délétère vis-à-vis de leur stabilité en formulation. Ensuite, le développement de préparations hydro-lipidiques a été initié en tenant compte, d’une part de la solubilité des différents composants et, d’autre part de l’injectabilité, des propriétés rhéologiques et des profils de libération de la clonidine obtenus à partir des gels développés. Cette étude visait à obtenir une composition de référence qui soit à la fois injectable et capable de libérer un principe actif hydrophile sur plusieurs jours, voire plusieurs semaines, tout en possédant des propriétés rhéologiques intéressantes dans le cadre d’une viscosupplémentation articulaire. Enfin, un protocole de fabrication en milieu aseptique a été développé et plusieurs méthodes pour étudier les propriétés physico-chimiques des gels développés telles que la rhéologie, l’injectabilité, l’indice de gonflement, la stabilité et les profils de libérations ont été mises en place.

Les résultats ont montré qu’aucune incompatibilité ne semblait exister entre les trois composés majeurs de notre préparation, la monoléine, l’acide hyaluronique et la clonidine. Le développement des formulations nous a ensuite permis d’obtenir de nouveaux systèmes hydrolipidiques stériles et injectables à délivrance prolongée. Le véhicule qui remplissait au mieux nos objectifs était composé de 10,0% (m/m) d’éthanol ;de 15,0% de propylène glycol (m/m) ;de 15,0% (m/m) d’eau ;de 55,0% (m/m) de monoléine ;5,0% (m/m) d’huile de soja purifiée ;0,03% (m/m) d’α-tocophérol, de 7,5 mg/g d’HA et son pH était ajusté à 6,5 avec du NaOH 1N. Ce véhicule a montré un intérêt réel dans le cadre du développement de préparations biodégradables et biocompatibles pour le traitement de pathologies articulaires.En effet, cette composition présentait un écoulement de type pseudoplastique et des propriétés rhéologiques qui lui procuraient une bonne injectabilité. De plus, cette formulation a démontré in vitro une excellente capacité à gélifier au contact de fluides aqueux et à ralentir efficacement sur plusieurs semaines la libération des différents principes actifs incorporés (clonidine et dipropionate de bétaméthasone). Nous pouvions, dès lors, envisager que celle-ci serait capable de gélifier in situ au contact d’un fluide physiologique tel que le liquide synovial. Ensuite, suivant les recommandations de l’EMA, nous avons décidé d’utiliser l’association d’une filtration stérilisante et d’une préparation en milieu aseptique pour obtenir des formulations qui répondaient aux exigences en matière de préparation parentérale. C’est ainsi qu’un protocole de fabrication stérile de nos gels a été développé par nos soins en vue d’une éventuelle mise à l’échelle industrielle. Enfin, une étude de stabilité sur une année, suivant les normes ICH décrites pour des formulations destinées à être conservées au frigo, a été réalisée sur différents véhicules développés et contenant soit la clonidine, soit le dipropionate de bétaméthasone. Dans cette optique, plusieurs paramètres, tels que le dosage en principe actif, l’évolution du pH et du poids moléculaire de HA, le profil de libération ainsi que la rhéologie des formulations ont été évalués au cours du temps aux différentes conditions de conservation testées. Cette étude a permis de démontrer toute l’importance d’ajuster le pH de la préparation pour prévenir l’hydrolyse de l’HA, et cela indépendamment de l’incorporation de principe actif. Ainsi, il a pu être montré que l’ajustement du pH du véhicule à 6,5 à partir de NaOH dilué permettait d’améliorer considérablement la stabilité de la formulation puisqu’aucune modification significative de ses différents paramètres physico-chimiques et teneurs n’a été observée après un an de conservation à 5 et à 25 °C (60% HR) mais également après six mois à 30 °C (65% HR). Au cours de cette première partie, deux collaborations ont été initiées, l’une avec le Laboratoire du Prof. Siepmann de l’Université de Lille 2 et l’autre avec le Prof. Jerôme de l’Université de Liège. Avec l’aide du Prof. Siepmann, il a été possible de mettre au point un modèle mathématique pour caractériser les profils de libération des principes actifs à partir des différents véhicules développés. Le Prof. Jerôme a, quant à elle, mis à notre disposition un rhéomètre qui a permis d’approfondir nos connaissances sur les propriétés rhéologiques et viscoélastiques des formulations.

Ensuite, la seconde partie de notre travail a consisté à évaluer la tolérance, ainsi que l’efficacité des principes actifs sélectionnés et des formulations développées, à travers un modèle in vitro de cellules de l’inflammation (neutrophiles équins). Cette étude avait pour objectif d’évaluer deux aspects importants de la formulation :d’une part vérifier l’absence de réaction pro-inflammatoire qui pourrait être in vivo destructrice vis-à-vis du véhicule ainsi que des tissus environnants, et d’autre part vérifier l’effet anti-inflammatoire propre à la clonidine et au dipropionate de bétaméthasone seuls et en formulation. Cette étude a été réalisée avec la collaboration du Laboratoire du Prof. Serteyn de l’Université de Liège.Cette étude in vitro a démontré que les cellules restaient viables au moins pendant quatre heures lorsqu’elles étaient exposées à la matrice épurée de ses solvants. Ensuite, de manière surprenante, il a même pu être démontré que le véhicule permettait à la fois de prévenir et de réduire significativement la production des espèces réactives de l’oxygène (ROS) par les neutrophiles équins lorsque ceux-ci étaient stimulés au phorbol 12-myristate 13-acetate (PMA). Cette propriété peut être d’un grand intérêt dans le cadre de la prise en charge de l’arthrose car cette activité antioxydante pourrait permettre d’inhiber les dommages oxydatifs générés par les ROS et ainsi prévenir les dommages liés au développement du processus inflammatoire et qui peut, à long terme, s’avérer délétère pour les tissus environnants tels que le cartilage. Cette propriété du véhicule semble trouver son origine dans la monoléine qui, de par sa composition en alpha-tocophérol (200 ppm), présente également une activité antioxydante vis-à-vis des ROS. Toutefois, une action synergique liée à l’HA, à l’huile de soja ou à l’alpha-tocophérol incorporés aux formulations, n’est pas à exclure. Enfin, parmi les deux principes actifs sélectionnés, seul le dipropionate de bétaméthasone a montré une inhibition significative de la production des ROS.

Enfin, en tenant compte des résultats obtenus sur cellules, une étude in vivo pilote a été réalisée sur base d’un modèle de lapins. Cette étude visait à vérifier la tolérance ainsi que l’efficacité en prophylaxie de l’arthrose du véhicule développé ainsi que de la formulation contenant le dipropionate de bétaméthasone. Dans ce but, quatre groupes d’animaux (n=8) ont été constitués pour chacun des traitements testés :(i) groupe témoin :0,9 % tampon salin pH 7,4 ;(ii) véhicule à base de GMO développé; (iii) véhicule contenant du dipropionate de bétaméthasone ;(iv) groupe référence :Durolane®. Cette étude a été réalisée avec l’aide du Laboratoire du Prof. Henrotin de l’Université de Liège. L’hébergement des animaux ainsi que les actes chirurgicaux ont, quant à eux, été sous-traités par TNO (Delft, Pays-Bas).

De manière étonnante, il s’est avéré que le groupe contrôle présentait des scores macroscopique et histologique globalement peu élevés par rapport à ce qui est rapporté dans la littérature. Compte tenu de cette observation, il est difficile de se prononcer, sur base uniquement de cette étude, sur l’efficacité des différents traitements testés. Toutefois, il faut reconnaître que l’effet protecteur attendu pour le véhicule vis-à-vis de la dégradation du cartilage ne semble pas optimal et cela indépendamment de l’incorporation de dipropionate de bétaméthasone. Par ailleurs, l’étude des membranes synoviales a permis de démontrer qu’il n’y avait aucune différence significative en termes d’inflammation et de structure entre le groupe contrôle et les différents groupes traités. Ce qui signifie qu’aucun rejet n’a été observé vis-à-vis des formulations et que celles-ci ont, par conséquent, été bien tolérées malgré la formation de masses liées probablement au volume important injecté (900 µL) et au gonflement in situ du produit chez 37,5 % des lapins. Cette observation est importante puisqu’elle permet d’envisager de nouvelles perspectives telles que l’incorporation d’autres principes actifs pouvant éventuellement viser d’autres pathologies articulaires et pour lesquels une libération prolongée ou une protection mécanique du principe actif in situ serait bénéfique.

Doctorat en Sciences biomédicales et pharmaceutiques
info:eu-repo/semantics/nonPublished

碩士
國立暨南國際大學
應用化學系
93
Triacylglycerides, presented in the cytoplasm of plant and animal cells, play an important biological role in energy vehicle and metabolism. They serve as the molecular form for storage of the fuel molecules. Adipocytes are specialized for fat storage in animal cells, which are regarded as storage depots of metabolic fuel. The primary function of lipases present in adipocytes, is to catalyze the hydrolysis of triacylglycerides and regulate adipocyte lipolysis, resulting in the release of glycerol and free fatty acids. A capillary sensor was developed for triglycerides and glycerol determination based on enzymatic reactions followed by the electrochemical detection. The hydrogen peroxide produced from the enzyme reaction is monitored by a platinum based electrochemical probe. Different immobilization strategies have been studied onto the inner wall of fused-silica capillary (0.53mm i.d). In present study, the best and the most effective configuration for measurement of triglycerides and glycerol in the tandem connecting of lipase reaction and the co-immobilized glycerokinase and glycerol-3-phosphate oxidase, in which lipase column was placed prior to the GK/G-3-P column. Lipase catalyzes the triglycerides to yield glycerol and fatty acid. Glycerol kinase catalyzes the adenosine-5-triphosphate dependent phosphorylation of glycerol to yield α-glycerol phosphate, which can subsequently be oxidized by glycerol-3-phosphate oxidase and produce hydrogen peroxide. The most optimum condition of the system is found to use a 20 ml injection loop, 2 mM ATP in 0.1 M carbonate buffer (pH 11.0) and a flow rate of 0.18 mL/min. Life time of the capillary enzyme reactor was up to 3 month by storage in the tris-buffered saline (TBS) at 4℃. Mouse 3T3-L1 fibroblasts differentiate when cultured and express a new phenotype, which is characteristic of adipose cells. A brief insulin treatment or epinephrine in 3T3-L1 cells was found to initiate the conversion of the triglycerides to glycerol, which could be subsequently detected by our previously developed flow analysis system for continuous monitoring of glycerol based on enzymatic reactions in conjugation with electrochemical detection. This real time glycerol senor for online detection of glycerol released by 3T3-L1 cells is useful for cell biology studies on the synthesis and breakdown of triglycerides, and subsequent glycerol release. It can be further used for screening the effectiveness of diet pills.

碩士
義守大學
化學工程學系暨生物技術與化學工程研究所
105
Gelatin was used as the main component in this research for developing artificial tissue emulating (ATE) materials. Gelatin has superior gelling properties in water. By combining with glycerol, the gelatin/water/glycerol mixtures possess higher toughness and better processability. Glutaraldehyde was also added as a crosslinking agent. Experimental tools such as Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC) and Dielectric Analysis (DEA) were employed to measure the electric, thermal and mechanical properties of the gelatin mixtures at different compositions. The DMA results showed for gelatin/water/glycerol mixtures that the storage moduli increased with increasing concentration of gelatin or glycerol. The melting temperatures also increased with increasing concentration of gelatin or glycerol. The addition of glutaraldehyde changed the gel system from being physically crosslinked to being chemically crosslinked. Lastly, the DEA results showed that the dielectric constants and the conductivities decreased with increasing gelatin or glycerol concentrations while the addition of glutaraldehyde had little effect on the electric properties. The addition of glycerol enhances the mechanical properties and water-retaining capability of the mixtures. The addition of glutaraldehyde changes the crosslinking behaviors and enhances the temperature resistance and mechanical properties of the mixtures.

博士
國立臺灣大學
醫學工程學研究所
100
Disc degeneration is strongly associated with back pain and herniation that increase the costs of health care. The degeneration of intervertebral disc (IVD) could be divided into 5 stages. In the first and second stages, there are no significant symptoms but could be traced by magnetic resonance imaging or computed tomography-scan. Generally, no aggressive treatment would be processed in the clinics. Recent studies indicated that overproduction of reactive oxygen species (ROS) may accelerate the degenerative process of IVD and associate with apoptosis of nucleus pulposus (NP) cells and degradation of extracellular matrix. Ferulic acid (FA) is an excellent antioxidant and relatively stable in air. FA has been proven to have ability to prevent ROS-induced diseases. The object of the study was aimed to evaluate the possible therapeutic effect of FA on hydrogen peroxide (H2O2)-induced oxidative stress NP cells and the feasibility of use the thermosensitive chitosan/gelatin/glycerophosphate (C/G/GP) hydrogel as a sustained release system of FA for early treatment in IVD degeneration. In the study, NP cells were harvested from the IVD of New Zealand rabbits. The results showed that 500 μM of FA might be the threshold to treat NP cells without cytotoxicity. Post-treatment of FA on H2O2-induced oxidative stress NP cells significantly up regulated the expression of aggrecan, type II collagen and BMP-7 and down regulated the expression of MMP-3 in mRNA level. Post-treatment of FA on H2O2-induced oxidative stress NP cells could restore the production of sulfated glycosaminoglycans (GAGs) and inhibit the apoptosis caused by H2O2. The results showed that the release of FA from C/G/GP hydrogel could decrease the H2O2-induced oxidative stress. Post-treatment of FA-incorporated C/G/GP hydrogel on H2O2-induced oxidative stress NP cells showed up-regulation of aggrecan and type II collagen and down-regulation of MMP-3 in mRNA level. The results of sulfated GAGs to DNA ratio and alcian blue staining revealed that the GAGs production of H2O2-induced oxidative stress NP cells could reach to normal level. The results of caspase-3 activity and TUNEL staining indicated that FA-incorporated C/G/GP hydrogel decreased the apoptosis of H2O2-induced oxidative stress NP cells. The results showed that FA was successfully immobilized on C/G/GP hydrogel by N-(3-dimethylaminopropyl)-N''-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) crosslinking method. The gelation temperature of the FA-immobilized C/G/GP hydrogel was 31.80 degree celsius under neutral pH. Post-treatment of FA-immobilized C/G/GP hydrogel on H2O2-induced oxidative stress NP cells showed down-regulation of MMP-3 and up-regulation aggrecan and type II collagen in mRNA level. The sulfated GAGs production of H2O2-induced oxidative stress NP cells could be increased to the normal level in the post-treatment of FA-immobilized C/G/GP hydrogel group. The results of caspase-3 activity and TUNEL staining showed that the apoptosis of H2O2-induced oxidative stress NP cells could be inhibited by post-treatment of FA-immobilized C/G/GP hydrogel. From the results of the study, FA could be used as a therapeutic molecule for NP regeneration and FA-incorporated C/G/GP hydrogel might be potentially applied as a long-term release system. The immobilization of FA on C/G/GP hydrogel could significantly prolong the release period of FA. These results suggest that combination of FA and thermosensitive C/G/GP hydrogel can treat NP cells from the damage caused by oxidative stress and may apply in minimally invasive surgery for NP regeneration in the future.