Дисертації з теми "Lignin nanoparticle"
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Linder, Kristoffer. "Optical Characterization of Lignin Nanoparticles." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79864.
Повний текст джерелаLignin är en av huvudbeståndsdelarna av trä och plantor som fungerar likt ett lim som ger mekanisk styrka. Lignin är en biopolymer, som består av tre fenylgrupper: p-hydroxifenyl (H), guaiacyl (G) och syringyl (S). På senaste tid har det visat sig att det är möjligt att tillverka lignin nanopartiklar, det är små sfäriska partiklar som är helt gjorda av lignin, som skulle kunna ersätta de miljöfarliga silver nanopartiklarna som i nuläget används i många olika tillämpningar. Lignin nanopartiklar kan potentiellt också användas som funktionella ytbeläggningar, såväl som biologiskt nedbrytbara lim och flottörer. Fem prover, av nanopartiklar, undersöktes i denna studie. Det första provet innehöll lignin nanopartiklar, det andra silver nanopartiklarna, och de tre återstående proverna innehöll ligninbelagda silver nanopartiklar, extraherade från aceton, tetrahydrofuran (THF) och dimetylformamid (DMF). Alla prover karakteriserades med hjälp av spektroskopiska metoder: infraröd- och mörkfältavbildning, liksom UV-Vis-, fluorescens- och Ramanspektroskopi. I denna avhandling visades att ligninbelagda silver nanopartiklar uppvisar ytplasmonsresonans, vilket inducerar en värmeeffekt vid infraröd bestrålning. För att identifiera ligninets fenylgrupper användes UV-Vis-spektroskopi. Det visade sig att spektra från proverna uppvisade flera intensiva band. Målet med UV-Vis-spektroskopin var att undersöka absorptionsegenskaperna hos de ligninbelagda silvernanopartiklarna. Möjliga ytplasmonresonansvåglängder bestämdes och två av fenylgrupperna identifierades. I denna studie användes Ramansspektroskopi för att definiera karakteristiska band för proverna. Detta gjordes för att undersöka om lignin nanopartiklarna har samma egenskaper som bulk lignin. Ramanspektroskopi ger information om ligninets struktur. Vidare identigierades p-hydroxifenyl-, guaiacyl- och syringylstrukturerna med en excitationsvåglängd på 532nm. En jämförelse av spektra för de lignininnehållande proverna indikerade att provernas Raman-kännetecken var liknande medan nästan inga tecken på silver fanns, vilket kan visa att partiklarna var täckta med lignin. Huvudsakliga ligninband kunde identifieras. Fluorescensegenskaperna, hos nanopartiklarna, undersöktes genom de erhållna emissionspektra efter exponering av blå-, grön- och UV-ljus. De erhållna spektra dekonvoluterades till dess gaussiska komponenter. Det visade sig att fluorescensen, efter exponering av UV-ljus, ökade med exponeringstiden. Mörkfältmikroskopi användes för att generera bilder på partiklarna. De resulterade i bilder med olika färger (vitt, gult, blått och rött) som motsvarade olika partikelstorlekar och geometrier. På så sätt kunde färhållandena mellan de olika partikelstorlekarna uppskattas. De ligninbelagda silver-nanopartiklarna, extraherade från aceton-lösningen, uppvisade en stark ytplasmonresonanseffekt, vilket kan bero på absorptionen (från absorptionsspektrat) vid 463nm. De ligninbelagda silver-nanopartiklarna, extraherade från DMF-lösningen, uppvisade en medelstark ytplasmonresonanseffekt, vilket kan bero på absorptionen vid 362nm. De ligninbelagda silver-nanopartiklarna, extraherade från THF-lösningen, uppvisade en svag ytplasmonresonanseffekt, vilket kan bero på absorptionen vid 379-380nm. De rena lignin- och silver-nanopartiklarna uppvisade endast uppvärmning men ingen ytplasmonresonanseffekt.
FERRUTI, FEDERICA MARIA CAMILLA. "NEW FUNCTIONALIZATION APPROACHES OF LIGNOCELLULOSIC FEEDSTOCK TO OBTAIN NEW REINFORCING FILLERS TAILORED TO RUBBER COMPOUNDS." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2023. https://hdl.handle.net/10281/403897.
Повний текст джерелаRubber products are commonly employed in a wide variety of industries including tire manufacturing, packaging, engineering and construction. The mechanical performances of rubber itself are unsatisfactory for the desired applications so the necessary improvements are commonly obtained by vulcanization and addition of reinforcing fillers in the elastomeric matrix. The most popular reinforcing filler is carbon black whose use is however associated with health and environmental concerns. For this reason, many tire manufacturers are concentrating their efforts in replacing carbon black with more sustainable alternatives. Their ambitions include the increment of renewable materials and the simultaneous reduction of fossil-based compounds in tire formulations, while preserving pr improving mechanical performances. In this frame, the present research project dealt with the development of sustainable reinforcing fillers for rubber compounds in alternative to fossil-based technologies with a particular focus on lignin. Despite its availability at industrial scale, the structural complexity of lignin has hampered its conversion into value-added products and the rational design of functional materials. However, the concerns about toxicity and environmental concerns related to the use of fossil-based materials are eliciting investigations regarding the use of renewable resources, included lignin. This material could be considered as a valuable alternative to carbon black in rubber compounds due to its good physical chemical and mechanical properties, antioxidant activity and thermal stability. However, its combination with an elastomeric matrix requires overcoming the poor compatibility between the two materials related to the polarity of lignin which results into strong self-interactions. So, it was necessary to modify lignin in order to improve the number and quality of its interaction with rubber resulting in a reinforcing effect. To ensure the desired reinforcement, two strategies were explored in the present project. The former dealt with the functionalisation of lignin hydroxyl groups ensuring the formation of covalent bonds between lignin and the rubber matrix during vulcanization. The procedure consisted in the mechanochemical esterification of lignin, allowing running reactions in the solid state, taking advantage of mechanical energy to trigger chemical transformations, avoiding organic solvents, limiting work-up procedures and reducing wastes with respect to wet chemistry syntheses. The latter consisted in the formulation of lignin into nanoparticles (LNPs)which are acknowledged to exhibit unique properties due to their high surface to volume ratio. Analytical investigations about solvent-extracted fractions guided the choice of specific lignin fractions for the development of LNPs with peculiar features. The innovative procedure allowed valorising the whole starting kraft lignin in a material efficient manner. It was possible to produce LNPs which proved dimensionally stable in a broad pH range 4.5-12.0 where lignin normally aggregates or dissolves The same approach allowed preparing LNPs with a surface-specific covalent functionalisation, an achievement never attempted in literature, to the best of our knowledge. The setup and scaleup of those procedures allowed for the formulation of innovative rubber compounds followed by the assessment of their dynamic-mechanical properties. The intriguing results proved promising for the development of technologically valuable and competitive rubber compounds including renewable materials.
la, Placa Antonia. "Comparison of Miscanthus grass lignin with spruce lignin from organosolv process for nanoparticles production." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278835.
Повний текст джерелаDet globala energibehovet ökar och samhället tvingas därmed att växla till förnybara resurser eftersom de fossila bränslena kan ta slut. Biomassa är en förnybar resurs som finns tillgänglig i stora mängder och kan därför bli en potentiell primär energikälla. Lignin, som är en väsentlig del av biomassan, används inte i lika stor utsträckning på grund av dess komplexa struktur. Komplexiteten begränsar därför användandet av lignin i värdeskapande produkter. Men en väg för att ta tillvara på lignins värdefulla egenskaper kan vara framställandet av nanopartiklar (NP), vilket öppnar upp för användning av lignin inom det biomedicinska fältet. Syftet med den här rapporten är att undersöka om lignin från olika botaniska ursprung påverkar nanopartiklarnas egenskaper, som exempelvis storlek, polydispersitet, 𝜁-potential och morfologi. NP av lignin från gräsarten Miscanthus sinensis framställdes genom solvent exchange och jämfördes sedan med NP från granlignin. Både miscanthus- och granligninet var isolerat genom organosolvprocessen. Den experimentella delen av arbetet visade att NP from miscanthuslignin gav partiklar inom intervallet 133.7 to 377.4 nm, där högre koncentration gav större partiklar, och medelvärdet för 𝜁-potentialen var -38.7 mV. Resultatet från arbetet visade att det botaniskt ursprunget påverkar både storleken och formen på NP av lignin som framställts med samma metod. NP från miscanthuslignin var större och hade en mer elliptisk form, i jämförelse med de mer sfäriska partiklarna från granlignin. Ligninkoncentrationen påverkade partikelstorleken för båda typerna av lignin, dessutom blev skillnaden i partikelstorlek större när koncentrationen ökade. Däremot var det svårt att dra någon generell slutsats genom att bara undersöka två olika ursprung. Eftersom det finns flera steg i processen från växters ursprung till NP av lignin som kan påverka partiklarnas egenskaper kan det vara nödvändigt att utforska både den tillämpade massaprocessen, isoleringsmetoden och metoden som används för att framställa NP av lignin.
Wessén, Anna, Eliot Diklev, and Lejla Al-Tamimi. "Development of magnetic lignin nanoparticles from low-molecular-weight eucalyptus and spruce lignin fractions." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277112.
Повний текст джерелаChollet, Benjamin. "Étude du comportement au feu de matériaux polymères contenant des bio-nanoparticules fonctionnalisées." Thesis, IMT Mines Alès, 2018. http://www.theses.fr/2018EMAL0004/document.
Повний текст джерелаThe growing desire to reduce the ecological footprint of plastic materials promotes the development of polymers and additives from renewable resources in order to limit their environmental impact. Flame retardants represent an important family of additives that play a crucial role in many fields where fire hazard is encountered. Thus this study aims at developing new flame retardant systems from biomass compounds to improve the fire behavior of polylactide (PLA), a bio-based polymer. Lignin and cellulose were chosen as pristine compounds. These compounds have been transformed into nanoparticles with adapted processes. Then, they were functionalized with phosphorous moieties or mixed with ammonium polyphosphate, and incorporated into polylactide with in internal mixer. Thermal, flammability and fire properties of these compounds were evaluated. The results obtained with some systems are promising
Petrie, Frankie Ann. "Magnetic-lignin Nanoparticles as Potential Ethanol Extractants from Aqueous Solutions." University of Dayton / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1563285930072497.
Повний текст джерелаGuthenberg, Kristoffer. "The impact of the pulping process on the properties of lignin nanoparticles." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278834.
Повний текст джерелаEn av utmaningarna för framtidens bioraffinaderier är att fullständigt utnyttja samtliga komponenter av råvaran. Historiskt sett har cellulosa varit den mest värdefulla komponenten av biomassan medan lignin har klassats som en biprodukt och har därför primärt bränts som bränsle vid framställning av pappersmassa. Även om lignin produceras på industriell skala saknas idag värdeskapande applikationsområden där lignin kan utnyttjas ur ett ekonomiskt hållbart perspektiv. Ett alternativ till valorisering av lignin är att använda det som råmaterial för framställande av nanopartiklar , vilket är ett relativ nytt område med stor potential framförallt inom biomedicin. Dock kvarstår en del utmaningar i forskningen runt lignin nanopartiklar. Framförallt relaterat till lignins komplexa och inhomogena struktur, som varierar beroende på botaniskt ursprung och vilken typ av massaframställningsprocess som används för att isolera ligninet från biomassan. Den här studien undersöker hur granlignin från två olika massaframställningsprocesser, Organosolv- och Kraftprocessen, påverkar egenskaper hos NP av lignin. Under den experimentella delen av arbetet framställdes NP från Organosolv granlignin, vilket resulterade i sfäriska och ihåliga partiklar som varierade i storlek mellan 104.5–270.3 nm, beroende på den initiala lignin koncentrationen, samt en genomsnittlig zeta potential kring -35 mV. Egenskaperna hos Organosolv nanopartiklarna som jämfördes med nanopartiklar av Kraflignin som producerats med samma metod. Slutsatsen drogs att organosolv partiklar var större och hade lägre absolut zeta-potential. Vilket troligtvis kan förklaras med den betydligt högre halten av fenoliska-OH enheter i Kraft ligninet. En bredare jämförelse med tidigare studier som producerat olika lignin nanopartiklar visar dessutom att molekylvikten, fenolisk-OH halt och produktionsmetoden, är bidragande faktorer till lignin nanopartiklars egenskaper. Sammanfattnings visar den här studien att den massaframställningsprocess som används för att isolera lignin kommer påverka egenskaperna hos lignin nanopartiklar. Men för att kunna generalisera och stärka slutsatsen krävs dock utökad experimentella, för att vidare undersöka hur lignin nanopartiklars egenskaper beror på egenskaperna hos ligninet som använts för att producera partiklarna.
Nunes, Andreia. "Hybrid mesoporous materials for the oxidative depolymerization of lignin into valuable molecules." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1024.
Повний текст джерелаLignin is one of the most abundant natural polymers and the only biomass constituent based on aromatic units and as such represents a promising renewable resource for the sustainable production of complex organic molecules. This dissertation reports on the development of catalytic materials capable of selectively transform lignin into basic functional molecules with high oxygen content and the study of their performance under alkaline oxidative conditions, using hydrogen peroxide as oxygen donner. Different families of hybrid materials based on the SBA-15 scaffold were first synthesized by incorporation of titanium, Au/titanium, Ag/titanium and Fe-TAML and completely characterized. Comparative catalytic studies were then accomplished in order to evaluate their performance in terms of degree of depolymerization and product distribution. The catalyst with the highest potential, the TiO2 based SBA-15 material, was then submitted to further reactivity studies in order to optimize the different reaction parameters (temperature, reaction time and quantity of oxidant). In the presence of an excess of oxidant, conversions up to 90 wt. % were obtained, whereas a temperature of 80 °C allowed to obtain a yield in bio-oil of 50 wt. %, which is mainly composed of carboxylic acids and aromatic molecules with potential to be further valorized
Marchand, Guillaume. "Synthèse et caractérisations de matériaux photosensibles à partir de lignines - Vers une utilisation en Traitement Photodynamique Antimicrobien appliqué à l'agronomie." Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0108/document.
Повний текст джерелаThe overexploitation of the planet's resources is nowadays a major problem and makes the replacement of non-renewable sources of energy and raw materials, one of the major challenges of the XXIe century. For this purpose, lignins, by their availability and their biocompatibility, appear as one of the alternatives to fossil resourcesIn this context, the PEIRENE Laboratory decided to carry out this PhD work on the development of new photosensitive materials based on modified lignins. For this purpose, three lignins from different origin were acetylated. Their study by EPR spectroscopy revealed that blocking their antioxidant functions considerably increases the quantity of reactive oxygen species they are able to generate under light irradiation. Thus it is possible to envisage the use of this modified biopolymer in many areas such as antimicrobial photodynamic therapy. In order to make them water-dispersible and thus to widen their field of applications, these materials with promising properties were put in the form of nanoparticles. Their photosensitive behavior has been also valuated by EPR spectroscopy. It has been demonstrated that once dispersed in water in the form of nanoparticles, the acetylated lignins were still capable of producing singlet oxygen under light irradiation. This activity, which has not yet been reported in the literature to our knowledge, however, remains quite limited and therefore needs to be improved. In order to widen the range of the solar spectrum allowing their activation, a photosensitizer has also been associated with these nano-objects by encapsulation and covalent grafting. The results of these studies make possible to envisage the development of systems based on acetylated lignins nanoparticles in in many field, in particular pharmaceutical and phytosanitary
Westphal, Emily Nicole. "Lignin-Magnetite Nanoparticles Aiding in Pickering Emulsions and Oil Manipulation and Their Rheological Properties." University of Dayton / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1619710097550949.
Повний текст джерелаDrozdová, Miroslava. "Jihomoravský lignit jako zdroj uhlíkových nanočástic." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449330.
Повний текст джерелаLi, Yang. "Application of cellulose nanowhisker and lignin in preparation of rigid polyurethane nanocomposite foams." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44746.
Повний текст джерелаAskri, Dalel. "Etude de la biodistribution et de la toxicité des Nanoparticules de Fer chez le rat et sur une lignée de neuroblastome." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAS021/document.
Повний текст джерелаIron Oxide Nanoparticles (IONPs) are used in several fields notably in Biomedicine as theranostic agents in Oncology and also as contrast agents in Magnetic Resonance Imaging. With the increase in the production and use of IONPs, there is a clear increase in human and environmental exposure to these NPs, which may pose a risk. The subject of my thesis is the study of the physiopathological impact and toxicity of iron oxide nanoparticles using a cell model of neuroblastoma and an animal study model, the Wistar rat. The aim of the research work of the in vitro part is to evaluate the cytotoxic and genotoxic effects as well as the effects on the expression of cellular proteins following the exposure of SH-SY5Y cells to increasing concentrations of iron NPs. We have shown that iron NPs induce cellular perturbations in a size and concentration dependent manner. Proteomic analysis followed by ontological gene annotation and signaling pathway analysis revealed the effects of IONPs on cytoskeleton, apoptosis and cancer development. The aims of our research carried out in vivo are to investigate the pathophysiological effects of iron NPs administered by three different routes, intravenous, intranasal and oral, also their impact on emotional and cognitive behavior as well as neurotransmitter and trace element homeostasis. The results showed that IONPs do not induce any changes in anxiety, locomotion, learning and memory in rats regardless of the administration route. However, these NPs cause a disruption of catecholamine and trace element levels in the brain. The most marked effects have been observed following intranasal instillation of NPs and are manifested by a decrease in serum iron levels, thrombocytosis and the presence of inflammatory foci in the liver. The comparative analysis of the three routes of administration showed that the intravenous route is the least toxic. Finally, the proteomic study of the proteomes of the brain, liver and lung has made it possible to evaluate the toxicity of the NPs of iron at the protein and molecular level. The obtained results provide an important support for the estimation and understanding of potentially adverse effects of these NPs, which have a certain toxicity that is not negligible from a molecular and physiopathological point of view. Thus, great care must be taken regarding their use in the biomedical field to minimize any risk related to IONP exposure in order to improve their biocompatibility and thus increase their benefits
Geng, Xi. "Bioenabled Synthesis of Anisotropic Gold and Silver Nanoparticles." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/86274.
Повний текст джерелаPh. D.
Wu, Xiayan. "Promoting nickel catalysts by visible-light illuminated gold and palladium nanoparticles." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/227208/1/Xiayan_Wu_Thesis.pdf.
Повний текст джерелаMao, Fei. "Réalisation des nanostructures désirées en or et en argent par effet thermique local induit optiquement : Application au stockage de données et à l’imprimante couleur." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASN011.
Повний текст джерелаThis work focuses on the investigation of plasmonic Gold (Au) and Silver (Ag) nanoparticles (NPs) by using optically induced local thermal dewetting technique and their applications. Firstly, Au and Ag NPs are fabricated by a thermal annealing method using a hot oven. This technique allows obtaining Au and Ag NPs, which are randomly distributed in a large area. The NPs sizes and properties are controlled by annealing conditions, such as annealing temperature and duration. Plasmonic properties of Au and Ag NPs are experimentally characterized and compared with the simulation ones performed by the FDTD method. These large-area Au and Ag NPs are demonstrated to be useful for applications in fluorescence enhancement and random laser. Secondly, we demonstrate a robust way to realize desired plasmonic nanostructures by using a direct laser writing method. This technique bases on optically induced local thermal effect allowing the realization of NPs at a small area, i.e. focusing area. By moving thus the laser spot, any desired plasmonic structure can be realized. The NPs sizes and distributions can be controlled by exposure doses (laser power and exposure time) and moving trajectory of the focusing spot resulting in different reflection or transmission colors. By focusing a continuous-wave laser at 532 nm on Au films having 50 nm thickness, we demonstrated for the first time the direct fabrication of plasmonic nanoholes array. These fabricated structures are demonstrated to be very potential for many applications such as data storage, color nanoprinter, fluorescence enhancement, and plasmonics based random laser
Baudino, Olivier. "Frittage photonique de lignes imprimées à base de nanoparticules : optimisation des propriétés électriques et mécaniques pour l’interconnexion de circuits intégrés sur substrats flexibles." Thesis, Saint-Etienne, EMSE, 2015. http://www.theses.fr/2015EMSE0804/document.
Повний текст джерелаPhotonic sintering is an emerging technology based on the instantaneous conversion ofabsorbed light energy by nanoparticles (NPs) into heat. In this work, it is used oninterconnections printed on flexible substrates by inkjet printing of a metal silver nanoinkwith particle mean diameter of Ø=25nm.A process parameters study has allowed us to link them (energy, frequency) with theinduced sheet resistance (120m!/ ). This has been confirmed through thermal modeling ofthe multilayer system, and also by monitoring the resistance variations in-situ duringphotonic sintering (a few ms) using an innovative characterization tool, allowingmeasurements every 4 μs. The electrical resistance stabilization correlated with the opticalproperties of the film was found to be optimal for an exposition of 2-3J/cm², whichcorresponds to heating up to approximately 200°C.Films microstructure analysis with X-ray diffraction enlightens the link between crystallitescoarsening and defaults density reduction. The minimization of electrical resistivity iscorrelated with neck growth between nanoparticles trigged by surface atomic diffusion.Moreover, a stronger cohesion between NPs improves the mechanical hardness compared toclassical oven curing.The electrical contact resistance (200m!) between a silicon chip interconnection bumpand printed tracks is measured thanks to an in-house setting for electrical measurement withthe nanoindenter. The level of forces to apply (300mN per bump) is optimized and transferredto a thermocompression by industrial equipment. A set of prototypes are fabricated andconfirm the compatibility of these technologies with a future industrial integration
Liu, Zhe. "Visible light driven fine organic synthesis using plasmonic materials as photocatalyst." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/206452/1/Zhe_Liu_Thesis.pdf.
Повний текст джерелаBarakat, Abdellatif. "Etude de la lignification de parois végétales de graminées par des assemblages modèles : Réactivité, organisation et structure supramoléculaire." Reims, 2007. http://theses.univ-reims.fr/exl-doc/GED00000531.pdf.
Повний текст джерелаLignocelluloses represent abundant and renewable biomass for which non food use still require an in-depth knowledge of the mechanisms involved in the architecture of lignified plant cell wall as the main lignocellulosic components. Owing to the highly complex mechanisms involved in planta in building the lignified cell walls; we attempted to study wall polymer interactions using chemical model systems. To this end, the supramolecular organization of composites made of xylans (as the main hemicelluloses of grass cell walls) and model lignin (DHP, DeHydrogenative Polymers) were investigated along in vitro polymerisation of lignin. In the lignified cell wall, xylans can be covalently linked to lignin via ferulic acid (FA) and/or via quinone methide (QM). The latter mechanism has been studied during lignin polymerisation in the presence of feruloylated xylan. Size exclusion chromatography (SEC) and NMR analysis of the DHP-xylans complex indicated that arabinose and QM are involved in covalent bonds between xylans and DHP. However, the formation of these linkages can be affected and controlled by non covalent interactions between the two polymers. In order to investigate the impact of the media concentration on the lignin monomer reactivity, highly concentrated DHPs were synthesised in increasing concentrations of xylans. Densification of the system was shown to impact on the monomer reactivity and consequently the DHP structure (increases of β-alkyl aryl ether bonds and of molar mass). The role of FA on xylan-DHP networks was further studied along polymerisation of the main lignin monomers, i. E. Syringyl (S) and guaiacyl (G) in the presence of xylans with different FA levels. DHP-xylan analysis by Light Scattering (LS), Size exclusion chromatography with online multi-angle laser light scattering (SEC-MALLS), Transmission electron microscopy (TEM), and Small Angles Neutron Scattering (SANS) showed that both FA and the type of lignin monomer (S and/or G) have a clear impact on the morphology and supramolecular organization of DHP-xylan nanoparticules
Carrard, Julie. "Impact d'une exposition aux nanoparticules de carbone couplées au benzo(a)pyrène sur la réponse inflammatoire dans des modèles expérimentaux d'asthme." Thesis, Lille 2, 2020. http://www.theses.fr/2020LIL2S004.
Повний текст джерелаAllergic asthma is a chronic inflammatory disease of the airways. It is characterized by therecruitment of inflammatory cells including CD4+ type 2 helper T-lymphocytes (Th), interleukin(IL)-4, IL-5 and IL-13 producers, eosinophils as well as mast cells and basophils. The prevalenceof asthma has continued to increase in recent decades and genetic changes cannot be solelyresponsible Air pollution, especially particulate matter, is suspected to be part of this rising trend.Atmospheric particles can be classified according to their aerodynamic diameter, includingultrafine particles (< 100 nm). These particles are potentially more harmful because of their smallsize, which gives them the ability to settle deep in the bronchial tree. They are also able to adsorbmolecules such as polycyclic aromatic hydrocarbons. However, some of these hydrocarbons,such as benzo(a)pyrene, are known to be harmful to health and in particular to the respiratorysystem. We investigated the effects of exposure to benzo(a)pyrene-bound ultrafine particles onthe inflammatory response in two experimental models of allergen-induced asthma. For this, weused a simplified model of particles from an industrial process that we call « nanoparticles ».In our first model, chronic exposure to carbon nanoparticles coupled or not to benzo(a)pyrene,was performed in C57Bl/6 mice sensitized intranasally to the allergen Dermatophagoidespteronyssinus. Nanoparticles had no effect on cell recruitment in allergen-inducedbronchoalveolar lavage. Surprisingly, co-administration of nanoparticles with the allergendecreased bronchial hyperreactivity compared to allergen alone. In contrast, we observed aneffect on lung tissue when co-exposed to benzo(a)pyrene-coupled nanoparticles and allergen.Indeed, this co-exposure induced a strong increase in Th2 cytokine expression and cellrecruitment in lung tissue compared to sensitized mice. In addition, this co-exposure modify thetype of cells recruited by the allergen, with an increase in the number of neutrophils, NKT-likecells, CD8+ T cells, Ly6C+ and Ly6C- monocytes/macrophages. These results were not found inco-exposure to nanoparticles not coupled to benzo(a)pyrene.In our second model, exposure to carbon nanoparticles, coupled or not with benzo(a)pyrène, wasperformed in C57Bl/6 mice sensitized intranasally with a low dose of the allergenDermatophagoides farinae. Preliminary results showed an adjuvant effect of nanoparticles withthe allergen on immunoglobulin E production but also on the inflammatory infiltrate in thebroncho-alveolar lavage, mainly composed of eosinophils. The expression of Th2 cytokines isalso increased by the administration of allergen with nanoparticles uncoupled to benzo(a)pyreneand not with benzo(a)pyrene-coupled particles. But, co-exposure of allergen withbenzo(a)pyrene-coupled nanoparticles induces the expression of Il-33, an alarmin produced bythe epithelium, which is also pro-Th2. In conclusion, our results suggest that nanoparticles have an impact on inflammation in allergensensitizedmice in our two experimental models. However, the dose, the amount of allergen andthe nature of the inhaled nanoparticles appear to influence the induced response in vivo
Cabrit, René. "Vectorisation d'anticancéreux par des nanoparticules de polyméthacrylate : étude comparative de la cytotoxicité des formes libres et liées sur une lignée cellulaire monoblastoi͏̈de humaine." Paris 5, 1989. http://www.theses.fr/1989PA05P207.
Повний текст джерелаBoscher, Virginie. "Modélisation de la polymérisation en suspension du chlorure de vinyle : étude granulométrique en ligne par spectroscopie acoustique d'émulsions modèles stabilisées par les." Thesis, Mulhouse, 2009. http://www.theses.fr/2009MULH3106.
Повний текст джерелаThis study focuses on the action mechanisms of poly vinyl alcohol-based macromolecular surfactants on the stabilization of vinyl chloride (VCM)/water emulsions used for the suspension polymerization of VCM. Five “primary” PVA (PVA I) with high hydrolysis degrees ( between 73 à 88 %mol) and different polymerization degrees ( between 700 à 2500), as well as one “secondary” PVA (PVA II) with 45%mol, have been studied on a large concentration range [0-1000 ppm/water]. The interfacial tensions and the size distributions of ClBu/water emulsions have been determined as a function of time. An original technique of on-line granulometry: the ultrasound attenuation spectroscopy has been used. The PVA I with low and are the most efficient stabilizers. For each PVA I, a direct correlation between mean diameter of droplets and interfacial tension has been established. Moreover, the importance of the interface viscoelasticity has been demonstrated. Because of their low , PVA II are insoluble in water. Well-defined colloidal particles of PVA II and combinations PVA I/ PVA II have been prepared by coacervation. For a given total PVA concentration, these nanoparticles of diameter 150-200 nm lower more the interfacial tension, and the mean droplet diameters, than PVA I alone. A Pickering stabilization by nanoparticles can be considered, in addition to the steric stabilization provided by PVA I
Mmelesi, Olga Kelebogile. "Synthesis and characterization of pine cone carbon supported iron oxide catalyst for dye and phenol degradation." Thesis, Vaal University of Technology, 2017. http://hdl.handle.net/10352/418.
Повний текст джерелаFenton oxidation is classified into two processes, homogeneous and heterogeneous. Homogeneous Fenton oxidation process, have been shown to be efficient in the degradation of organic pollutants. However, it was shown to have limitations which can be addressed by the heterogeneous Fenton oxidation. Despite the high efficiency of the heterogeneous Fenton oxidation process in the degradation of recalcitrant organic pollutants, the currents synthesis trends of the heterogeneous Fenton catalyst have been proven to be time and energy constraining, since it involves the multi-step were the activated carbon have to be prepared first then co-precipitate the iron oxide on the activated carbon. However, as much as the heterogeneous Fenton catalyst has been proven to have high catalytic activity towards degradation of organic pollutants, these catalysts have some limitations, such limitations include metal ions being leached from the catalyst support into the treated water causing catalyst deactivation and a secondary pollution to the treated water. In this thesis, these catalysts have been applied in the degradation of recalcitrant organic pollutants such as methylene blue and phenols. This study focuses on the single step synthesis of iron oxide nanoparticles supported on activated carbon, were carbonaceous material is impregnated with iron salt then pyrolysed via microwave heating. Microwave power and the amount of iron salt were optimized. The prepared activated carbon-iron oxide composites were applied to the degradation of 2-nitrophenol (2-NP) and methylene blue (MB). Methylene blue was used as a model compound due to the fact that it is easier to monitor the degradation process with UV-Vis as compared to 2-nitrophenol . 2-nitrophenol the additional step for the adjustment of pH is required since nitrophenols are colorless in color at lower pH. The characterization showed that the microwave power and the amount of the iron precursor have an influence on the porosity and surface functional groups of the activated carbon. Further it was vi observed that microwave power and iron precursor influnces the amount of iron oxide formed on the surface of the support. It was also observed that the activated carbon-iron oxide composite have the catalytic effects on the Fenton oxidation process of MB and 2-NP. The parameters such as H2O2, pH, catalyst dose, initial concentration, temperature affect the degradation of both MB and 2-NP. Kinetics studies showed that Fenton is a surface driven reaction since the results fitted the pseudo first order model. The thermodynamics parameters also showed that the reaction is endothermic, spontaneous and is randomized. This implies that the reaction of the degradation of MB and 2-NP is feasible and the catalysts prepared have high catalytic activity. MB and 2-NP were degraded to smaller organic molecules (carboxylic acids). The stability of the catalyst observed to decrease as the number of cycles increased, this is due to the leaching of iron ions from the support material. Hence it was concluded that the activated carbon-iron oxide composite was successfully synthesized and had the high catalytic activity for the degradation of MB and 2-NP.
Ferro, Cláudio Alexandre Rodrigues. "Lignin nanoparticles for cancer therapy." Master's thesis, 2017. http://hdl.handle.net/10451/36012.
Повний текст джерелаTrabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2017
Recently, lignin has been used as a starting material for the development of nanoparticles (NPs) for different purposes, including for biomedical applications. In this study, the carboxylation of the native lignin was carried out towards the modification of carboxylated lignin NP (CLNPs) with a block copolymer made of poly(ethylene glycol) (PEG), poly(histidine) (PHIS) and cell-penetrating peptide (CPP). The success of the conjugation reactions was confirmed by the conversion of the zeta-potential (ζ-potential) values from negative values for the bare CLNPs to positive values after the surface functionalization. The prepared CLNPs showed spherical shape, good size distribution, moderate polydispersity, good stability in physiological media and low cytotoxicity in all the tested cell lines at a concentration up to at least 250 µg/mL, after 24 h of incubation. A poorly water-soluble cytotoxic agent, benzazulene (BZL), was loaded into the CLNPs, improving its release profiles at pH 5.5 and 7.4. Furthermore, the release of BZL was found to be pH-sensitive, with higher release rates at pH 5.5 than at pH 7.4. Consequently, the BZL-loaded CLNPs conjugated with PEG-PHIS-CPP (BZL@CLNPs-PEG-PHIS-CPP) showed an enhanced antiproliferative effect in the different cancer cells (IC50 < 24 µM) compared to a normal endothelial cell line (IC50 ≈ 45 µM) after 24 h incubation, making the CLNPs promising candidates for anticancer therapy.
Recentemente, a lignina tem sido utilizada como matéria-prima para o desenvolvimento de nanopartículas para diferentes fins, incluindo para aplicações biomédicas. Neste estudo, procedeu-se à carboxilação da lignina nativa tendo em vista a modificação de nanopartículas de lignina carboxilada (CLNPs) com um copolímero constituído por poli(etilenoglicol) (PEG) e poli(histidina) (PHIS). A superfície das CLPNs também foi funcionalizada com um Péptido de Penetração Celular (CPP). O sucesso das reações de conjugação foi confirmado pela conversão dos valores negativos do potencial zeta obtido para as CLNPs puras, para valores positivos após a funcionalização da superfície destas nanopartículas. As CLNPs apresentaram forma esférica, boa distribuição de tamanhos, polidispersão moderada, boa estabilidade em meios fisiológicos e baixa citotoxicidade em todas as linhas celulares testadas em concentrações até pelo menos 250 μg/mL, após 24 h de incubação. Um agente citotóxico pouco solúvel em água, benzazulina (BZL), foi encapsulado nas CLNPs, melhorando os seus perfis de libertação a pH 5,5 e 7,4. Além disso, a libertação de BZL foi sensível ao pH, com taxas de libertação mais elevadas a pH 5,5 do que a pH 7,4. Consequentemente, as CLNPs conjugadas com PEG-PHIS-CPP contendo BZL (BZL @ CLNPs-PEG-PHIS-CPP) mostraram um efeito antiproliferativo aumentado nas diferentes células cancerígenas (IC50 <24 μM), em comparação com uma linha celular endotelial normal (IC50 ≈ 45 μM) após 24 h de incubação, o que torna as CLNPs alternativas terapêuticas promissoras para o tratamento do cancro.
Gonugunta, Prasad. "Synthesis and Characterization of Biobased Carbon Nanoparticles from Lignin." Thesis, 2012. http://hdl.handle.net/10214/3608.
Повний текст джерелаOntario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) New Directions Research Program for funding the project (number SR 225).
Maldonado, Carmona Nidia. "Acetylated lignin nanoparticles as a new photosensitizer’s vehicle for Photodynamic Antimicrobial Chemotherapy (PACT)." Doctoral thesis, 2021. http://hdl.handle.net/10316/98812.
Повний текст джерелаAntibacterial resistance is a threat to the developments of modern medicine, representing an economic, and social burden in years to come. This crisis is enhanced by a belittled pipeline of novel antibacterial drugs, due to the high research costs and low profitability. Furthermore, the development of new, specific molecules is not guarantee that antibacterial resistance will not arise against any new molecule, and then there is a growing tendency to look for antibacterial alternatives with unspecific molecular targets. In this aspect, Photodynamic Antimicrobial ChemoTherapy achieves bacterial disinfection through the use of a photosensitizing molecule which is only active upon light irradiation, adding another level of control to the process. In this work, we present a biopolymeric delivery system for photosensitizing molecules, as acetylated lignin nanoparticles. The preparation, physical characterization and photophysical characterization are discussed along this project, exploring the effects of the encapsulation towards the photosensitizer. Finally, these nanoparticles were tested against bacteria, finding that they were able to efficiently eradicate them only upon light irradiation, demonstrating low dark toxicity, and stability over time and light exposure. Then, this formulation for photosensitizing molecules has proven to be an efficient antibacterial formulation, fulfilling its purpose, while tackling antibacterial disinfection and valorizing a highly abundant biopolymer.
Freitas, Filipa Marlene Carvalho. "Production and characterization of lignin nanoparticles derived from lignocellulosic biomass." Master's thesis, 2018. http://hdl.handle.net/1822/59146.
Повний текст джерелаLignin is one of the most abundant polymers and renewable resource obtained from lignocellulosic biomass. Organosolv is a promising chemical pretreatment that involves the use of organic solvents such as methanol, ethanol or acetone for extracting lignin. Regarding to other pretreatment technologies, organosolv process is able to produce a high purity (low inorganic impurities and sulfur-free) and low molecular weight (Mw) lignin. Due to its aromatic structure, lignin is a promising raw material for the synthesis of different biomaterials. Furthermore, the production of lignin nanoparticles (LNPs) gained prominence due to their biodegradability and bioactive properties. However, the properties of nanoparticles from organosolv lignin (OL) are unclear. For this reason, the objective of this work was the production and characterization of LNPs. For that, LNPs were produced from ethanol organosolv lignin using the nanoprecipitation method. Two types of LNPs were optimized: LNPs 100 nm and LNPs 300 nm, which presented a spherical shape, narrow size distribution and a reduced polydispersity. The thermal stability of these LNPs was improved regarding to raw lignin, and the chemical structure of lignin was not affected when the LNPs were produced. The antimicrobial preliminary tests proved that LNPs with 300 nm presented a bacteriostatic effect on E. coli O157:H7 and Salmonella Typhimurium. Relatively to the antioxidant effect, LNPs presented a lower RSA than raw lignin. However, when increased the time of reaction and the concentration of LNPs, this value was very similar to the raw lignin. Additionally, the LNPs showed a low cytotoxic effect in Caco-2 cell line in a time dependent-manner. Furthermore, the LNPs presented an antioxidant effect against intracellular ROS in a concentration-manner (0.005 and 0.01 mg/mL) These results showed that it was possible to obtain LNPs with good physico-chemical properties and with potential for high value applications such as biomedical, pharmaceutical and food applications.
A lignina é um dos polímeros mais abundantes e um recurso renovável obtido a partir da biomassa lignocelulósica. Organosolv é um pré-tratamento químico promissor que envolve o uso de solventes orgânicos como o metanol, o etanol ou a acetona para a extração da lignina. Em comparação com outras tecnologias de pré-tratamento, o processo organosolv é capaz de produzir uma lignina de alta pureza (baixa impureza inorgânica e livre de enxofre) e de baixo peso molecular (Mw). Devido à sua estrutura aromática, a lignina é uma matéria-prima promissora para a síntese de diferentes biomateriais. Além disso, a produção de nanopartículas de lignina (LNPs) ganhou destaque devido à sua biodegradabilidade e propriedades bioativas. Contudo, as propriedades das nanopartículas produzidas a partir de lignina organossolv não são claras. Por esse motivo, as LNPs foram produzidas a partir da lignina organosolv utilizando o método de nanoprecipitação. Dois tipos de LNPs foram o desenvolvidas: LNPs 100 nm e LNPs 300 nm, que apresentaram uma forma esférica, estreita distribuição de tamanho e uma polidispersividade reduzida. A estabilidade térmica dessas LNPs foi melhorada quando comparada à lignina bruta, e a estrutura química dos LNPs não foi afetada quando estas foram produzidas. Os testes antimicrobianos preliminares comprovam que os LNPs com 300 nm apresentam um efeito bacteriostático nas estirpes bacterianas de E.coli O157:H7 e Salmonella Typhimurium. Relativamente ao efeito antioxidante, as LNPs apresentam uma menor RSA do que a lignina bruta. No entanto, quando aumentamos o tempo de reação e a concentração, esse valor é muito semelhante ao da lignina bruta. Adicionalmente, as LNPs mostraram um baixo efeito de citotoxico na linha celular Caco-2. No entanto este efeito citotoxico aumenta quando aumentamos o tempo de incubação e quando a concentração de LNPs é maior. Além disso, os LNPs apresentam um efeito antioxidante contra as ROS intracelulares, quando a concentração destas LNPs é maior (0.05 e 0.1 mg/mL). Estes resultados mostraram que foi possível obter LNPs com boas propriedades físico-químicas e com potencial para aplicações de alto valor como aplicações biomédicas, farmaceuticas e na indústrial alimentar.
Karuppaiya, Palaniyandi, and 卡路百亞. "In vitro production of anti-cancer compounds, expression of lignan biosynthetic pathway gene(s) and anti-cancer activity of biogenic metal nanoparticles synthesized from Dysosma pleiantha." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/19172428282479770872.
Повний текст джерела朝陽科技大學
應用化學系生化科技博士班
101
Abstract Dysosma pleiantha (Hance) Woodson, (Berberidaceae) is a herbaceous, rhizomatous perennial, highly prized by the mountain tribes of Taiwan for its medicinal properties. It has long been used as a traditional Chinese medicine for general remedies including treatment of snakebite, condyloma, weakness, lymphadenopathy and tumors. It contains lignans, flavonoids and steroids and these compounds are accumulated abundant in rhizome. These lignans and flavonoids have potential application in anticancer activities. In recent years, natural populations of D. peliantha have declined considerably due to anthropogenic activities such as habitat destruction and over exploitation for medicinal applications. Thus, the present study focused on the quantification of anticancer compounds in D. pleiantha collected from different geographical regions, in vitro callus culture and production of anticancer compounds under the influence of organic additives, isolation, cloning, characterization and expression analysis of lignan biosynthetic pathway genes and anticancer activity of biologically synthesized metal nanoparticles from D. pleiantha rhizome. At first, we have quantified the podophyllotoxin, quercetin and kaempferol in different parts and rhizome of D. pleiantha collected from different geographical regions using RP-HPLC. Initially we have used different mobile phase in various combinations for the simultaneous detection of podophyllotoxin, quercetin and kaempferol. Among the different solvent used, water and methanol in the ratio of 50:50 gave symmetric and high peak area. The quantitative analysis of different parts of D. pleiantha showed that the rhizome was the best source for the extraction of medicinally important podophyllotoxin as compared to other plant parts, whereas both quercetin and kaempferol were mainly distributed in stem, roots and rhizome as compared to leaf and petioles. On the other hand, the rhizome of D. pleiantha collected from different geographical area result showed that the rhizome collected from Hsinchu, Miaoli, Nantou and Yangminshan showed maximum podophyllotoxin accumulation than the rhizome grown in Alishan. In the case of quercetin, Alishan and Miaoli chemotypes possess maximum accumulation than other chemotypes, whereas, kaempferol were abundantly accumulated in all the chemotypes with slightly lower in Hsinchu and Yangminshan. The second major part of the study is focused on in vitro callus culture of D. pleiantha and production of important anticancer compounds such as podophyllotoxin, quercetin and kaempferol. Among the different explants used, the leaf produced 100 % callus frequency and the leaf callus was further investigated for mass multiplication and secondary metabolite content. We found that the callus grown on B5 medium (Gamborg et al., 1968) supplemented with 1 mg/L 2,4-D under dark condition produced maximum biomass of callus. Further, the callus was cultured under different concentration of organic additives. Among the different concentration of various additives used, the leaf callus cultured on B5 medium supplemented peptone (1-4 g/L) is most suitable for the callus biomass induction and production of lignan and flavonoids. The third part of the thesis aims on isolation, cloning, characterization and expression of lignan biosynthetic pathway genes in D. pleiantha. We have successfully isolated two genes namely secoisolariciresinol dehydrogenase (DpSD) and pinoresinol synthase (DpPS) from D. pleiantha using PCR based approach. The expression of DpSD and DpPS genes in different parts of D. pleiantha were analyzed using qRT-PCR. We found that both DpSD and DpPS mRNA accumulates predominantly in rhizome. The fourth part of the study investigates the anti-metasatic activity of biologically synthesized gold nanoparticles on human fibrosarcoma cell line HT- 1080. The biosynthesized gold nanoparticles were confirmed and characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy equipped with energy dispersive spectroscopy. The results revealed that aqueous extract of D. pleiantha rhizome has potential to reduce chloroauric ions into gold nanoparticles and the synthesized gold nanoparticles were showed spherical in shape with an average size of 127 nm. Further, we investigated the anti-metastatic activity of biosynthesized gold nanoparticles against human fibrosarcoma cancer cell line HT- 1080. The results showed that the biosynthesized gold nanoparticles were non-toxic to cell proliferation and, also it can inhibit the chemo-attractant cell migration of human fibrosarcoma cancer cell line HT-1080 by interfering the actin polymerization pathway. Final part of the thesis covered anticancer activity of biologically synthesized silver nanoparticles on breast cancer and AGS colon cancer cell lines. In this study, silver nanoparticles were successfully synthesized by a rapid biological synthetic method from aqueous rhizome extract of Dysosma pleiantha. The synthesized Dp- AgNPs were characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy equipped with energy dispersive spectroscopy. Further, we tested for its efficiency as a potent cytotoxic agent against breast and colon cancer cell lines. It was observed that the synthesized silver nanoparticles induced concentration dependent inhibition of cell proliferation in both breast and colon cancer cells.
Gomes, Neide Marisa Costa. "Advanced Supported and Non Supported Polyoxometalate Materials for Oxidative Catalytic Reactions." Master's thesis, 2017. http://hdl.handle.net/10362/29114.
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