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Peters, Steven Carlton. "Crosslinked amino acid derivatives." Title page, table of contents and abstract only, 1991. http://web4.library.adelaide.edu.au/theses/09PH/09php4831.pdf.
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Harwood, Eric Alexander. "Chemical synthesis and structural characterization of a nitrous acid interstrand cross-linked duplex DNA /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/8702.
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Parzel, Cheryl A. "Tannic acid crosslinked collagens and potential for breast tissue engineering." Connect to this title online, 2006. http://etd.lib.clemson.edu/documents/1171041544/.
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Nebipasagil, Ali. "Chemically and Photochemically Crosslinked Networks and Acid-Functionalized Mwcnt Composites." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/42703.
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PTMO-urethane and urea diacrylates (UtDA, UrDA) were synthesized from a two-step reactions of bis (4-isocyanatocyclohexyl) methane (HMDI) with either α,Ï -hydroxy-terminated poly (tetramethylene oxide) (PTMO Mn 250, 1000, 2000 and 2900 g/mol) or α,Ï -aminopropyl-terminated PTMO and 2-hydroxyethyl acrylate (HEA). PTMO-based ester precursors (EtDA) were also synthesized from α,Ï -hydroxy-terminated PTMO (Mn 1000 and 2000 g/mol). Two bis acetoacetates were synthesized from acetoacetylation of 1,4-butanediol and 250 g/mol hydroxy-terminated PTMO with tert-butyl acetoacetate. 1H NMR spectroscopy confirmed the structure and average molecular weights (Mn)of diacrylates. Mn of these precursors were in the range of 950 to 3670 g/mol by 1H NMR. The rheological properties of diacrylates were studied and activation energies for flow were calculated. Activation energies increased with increasing Mn and hydrogen-bond segment content. Michael carbon addition was employed to covalently crosslink the precursors resulting in networks with gel fractions better than 90%. DSC and DMA experiments revealed that networks had a broad distribution of glass transition temperatures depending on Mn and degree of hydrogen bonding present in the diacrylates. Their Tgâ s varied from -61 ºC to 63 ºC depending on the crosslinking density and hydrogen-bonding segment content. TGA revealed that UtDA and UrDA networks had an improved thermal stability compared to their EtDA counterparts. Tensile properties showed a variation depending on the structure and Mn of diacrylate and BisAcAc precursors. The storage moduli of networks precursor change from 25.3 MPa to 2.0 MPa with increasing Mn of the urethane diacrylate Elongation at break increased from 255% to 755 % for the same networks. The Youngâ s moduli increased from 3.27 MPa for EtDA 2000 to 311.1 MPa for UrDA 2000 which was attributed to increasing degree of hydrogen-bonding.
Acid functionalization of C70 P Baytubes multiwalled carbon nanotubes (MWCNT) generated acid-functionalized nanotubes (MWCNT-COOH). Suspension of MWCNT-COOH in organic solvents (chloroform, toluene, THF, DMF and 2-propanol) were prepared. DLS indicated average particle diameters of MWCNT-COOH in DMF and in 2-propanol were 139 nm and 162 nm respectively. FESEM of suspensions revealed aggregate free dispersion of MWCNT-COOH in DMF and 2-propanol. MWCNT-COOH containing composite networks were prepared. FESEM images of fracture surfaces of UtDA showed MWCNT-COOH were well-dispersed in the composites. DMA showed an increase in the rubbery plateau modulus which correlated with the MWCNT-COOH content in the networks. Tensile testing also revealed a relationship between MWCNT-COOH content and youngâ s moduli and strain at break of networks. Storage moduli of networks increased from 25 MPa to 211 MPa with increasing MWCNT-COOH content whereas elongation at break decreased from 255 % to 146 %.
UtDAs and pentaerythritol tetraacrylate (PETA) were crosslinked under UV radiation (6 passes, 1.42 ± 0.05 W.cm2 for each pass) in the presence of 2,2-dimethoxy-2-phenylacetophenone (DMPA) (1 wt. % of the mixture) UV initiator. DMA demonstrated the presence of broad glass transition regions with a range of Tgâ s which varied from -60 °C to -30°C. Tensile testing also revealed the relationship between Youngâ s moduli, strain at break and the molecular weight of the diacrylates. The increasing molecular weight of urethane diacrylate precursors caused a drop in the storage moduli of networks from 15.8 MPa to 1.4 MPa and an increase in elongation at break from 76 % to 132 %.Master of Science
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Siu, King-sun, and 蕭景新. "Development of crosslinked poly(ethylenimine) as a potential nucleic acid delivery agent." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43223874.
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Siu, King-sun. "Development of crosslinked poly(ethylenimine) as a potential nucleic acid delivery agent." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43223874.
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Zhou, Lei. "INVESTIGATION OF THE SHAPE MEMORY BEHAVIOUR OF STEARIC ACID SWOLLEN, CROSSLINKED EPDM ELASTOMERS." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron155560618552726.
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Seo, Junyoung. "D-Glucaric Acid Based Polymers and Crosslinker:Polyesters Bearing Pendent Hydroxyl Groups andDissolvable Chemically Crosslinked Gels." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1563550430288194.
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Molano, López Astrid Catalina [Verfasser], Andrij [Akademischer Betreuer] Pich, and Walter [Akademischer Betreuer] Richtering. "Supramolecular stimuli-responsive microgels crosslinked by tannic acid / Astrid Catalina Molano López ; Andrij Pich, Walter Richtering." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1193656648/34.
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Portero-Muzy, Nathalie. "Comparaison des effets précoces d’un agent anti-résorbeur et d’un agent anabolique sur le remodelage osseux et la microarchitecture chez la brebis âgée." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10206.
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Les effets des agents anti-ostéoporotiques sur le tissu osseux sont évalués au niveau de la crête iliaque (CI) mais les réponses aux traitements peuvent varier selon le site osseux. Le but de cette étude était de comprarer les effets de l’acide zolérodronique (ZOL) et du tériparatide (TPTD) au niveau de la crête iliaque et de la vertèbre lombaire L1 (VL1) chez la brebis âgée. Le ZOL a induit une forte diminution du remodelage osseux et une augmentation des microendommagements au niveau des deux sites et une modification des crosslinks du collagène surtout au niveau de l’os cortical de la CI. Trois mois de TPTD ont augmenté le remodelage osseux uniquement au niveau de la VL1. En conclusion, les délais et les amplitudes de réponses au ZOL ou au TPTD diffèrent entre la CI et la VL1 chez la brebis. Ces résultats montrent l’importance de prendre en compte le site osseux pour évaluer les effets des agents anti-ostéoporotiquesThe effects of anti-osteoporotic agents on bone tissue are evaluated on iliac crest (IC) but the answers to treatments may vary according to the skeletal site. The purpose of this study was to compare the effect of zoledronic acid (ZOL) and teriparatide (TPTD) on IC and lumbar vertebrae (LV1) in ewes. ZOL has induced a high decrease of bone remodeling, an increase in microdamages in both sites and a modification of collagen crosslinks mainly in cortical bone of IC. Three months of TPTD has increased the bone remodeling only in LV1. In conclusion, the delays and the magnitudes of responses to ZOL or to TPTD differ between IC and LV1 in ewes. These results show that the distinction of bone sites to study the early effects of antiosteoporotic therapies appears meaningful
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Liu, Dongmin. "The Effects of Dietary Lipids on Bone Chemical, Mechanical and Histological Properties in Japanese Quail (Coturnix C. Japonica)." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/28149.
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Japanese quail were used as animal models in four experiments to evaluate the effects of supplementing diets with different lipids on bone chemical, mechanical, and histological properties. In Exp. 1, laying hens were fed a basal diet containing either 5% soybean oil (SBO), hydrogenated soybean oil (HSBO), chicken fat (CF), or menhaden fish oil (FO). The addition of SBO in the maternal diet increased the levels of total n-6 fatty acids and arachidonic acid (AA, 20:4n-6) in yolk and tibial bones of newly hatched progeny (P<0.01), whereas the maternal FO diet elevated the concentrations of total n-3 fatty acids, eicosapentaenoic acid (EPA, 22:5n-3), docosahexaenoic acid (DHA, 22:6n-3) and total saturated acid, but greatly decreased the amount of AA in both egg and progeny tibiae (P<0.01). The maternal HSBO diet resulted in the accumulation of trans-18:1 fatty acid in egg yolks and tibiae at hatch. The addition of FO or HSBO to the maternal diet significantly lowered the ex vivo PGE2 production of tibiae in newly hatched quail compared to those from hens given the SBO or CF diets (P<0.01). In Exp. 2, the addition of different lipids in the maternal diets did not affect growth, tibial length, diameter or collagen content of the progeny. However, supplementing the maternal diet with 5 % FO or HSBO increased the percent bone ash , increased bone pyridinium crosslinks of collagen, enlarged the cartilaginous proliferative and hypertrophied zones, increased diaphyseal cortical thickness of the tibiae in embryos (P<0.05), and subsequently increased tibial shear force, stiffness (P<0.05) and improved cortical thickness, density and trabecular density in early growth and development of progeny compared to those from hens consuming the SBO or CF diets (P<0.05). In Exp. 3, male quail at one month of age were fed a basal diet containing either 5% SBO, HSBO, CF or FO for seven months. Long-term supplementation in the diets of different lipids did not affect body weight, food intake, tibial length or diameter, but the FO group had the highest tibial percent ash, and both FO and HSBO increased tibial mineral content in aged quail compared to those fed the SBO or CF diets (P<0.05). At 8 months of age, quail fed FO had the highest concentrations of (n-3) fatty acids (20:5n-3, 22:5n-3, 22:6n-3) but the lowest amounts of 20:4n-6 in lipids from tibial cortical bone, whereas the SBO and CF diets greatly elevated (n-6) fatty acids and 20:4n-6 levels. The HSBO diet which contains t18:1 fatty acid resulted in t18:1 accumulation in bone. Long-term supplementation with FO or HSBO increased tibial shear force, stiffness and shear stress, as well as improved cortical thickness and density compared with the SBO or CF diets
( P<.05). In Exp. 4, the addition of SBO or CF to the diet for seven months decreased tibial mineral content compared to the FO diet (P<0.05). Quail fed SBO increased collagen concentration in the tibiae (P<0.05), but the level of collagen crosslinks was higher in quail fed FO or HSBO compared to those given the SBO or CF diets (P<0.05). The PGE2 production in bone organ culture and marrow was greatly increased in quail maintained on the SBO or CF diets (P<0.05). PGE2 production in the bone microenvironment was negatively correlated with the tibial percent ash and collagen crosslinks but had a positive correlation with tibial collagen concentration. The results of these studies demonstrate that either supplementing the maternal diets with or long-term exposure to different lipids alters the chemical composition and metabolism of skeletal tissue in both embryos and aged quail. Maternal dietary SBO or CF had an adverse effect on bone growth and development in embryos. Likewise, long-term exposure to SBO or CF diet impaired bone metabolism and remodeling. In contrast, the FO or HSBO diet had beneficial effects on bone modeling in embryos and remodeling in adult quail.Ph. D.
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Chi, Yuan. "The Influence of Citric Acid, Glycerol and pH on Crosslinking and Their Effects on the Morphology, Mechanical and Thermal Properties of Tapioca Starch Films." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563494987482215.
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Khadivi, Heris Hossein. "Investigation of a hyaluronic acid-gelatin crosslinked microgel-hydrogel extracellular matrix for superficial lamina propria restoration in scarred vocal folds." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119589.
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Voice problems often involve physical injury and they have serious emotional, functional and economic consequences. The present research project contributes to the development of an injectable biomaterial for potential use in treating vocal fold (VF) lamina propria (LP) scarring disorder. A new biomimetic hydrogel system, based on hyaluronic acid (HA) and gelatin (Ge), with hierarchical structural organization was designed, characterized, and evaluated in vitro and in vivo. This hierarchical composite hydrogel was constituted from hybrid HA–Ge microgels, fabricated through water-in-oil mini-emulsification polymerization, embedded in a secondary HA network. Experiments were performed to investigate the suitability of such hierarchical network for VFLP tissue engineering. Scanning electron microscopy confirmed the spherical topography of the microgels. Scanning confocal microscopy of the microgels, with fluorescently stained gelatin molecules, indicated that gelatin molecules distribute evenly inside and on the HA–Ge microgels. The Young's modulus of the HA–Ge microgels was 22±2.5 kPa. The overall shear elastic modulus was 75±15 Pa at the frequency of 1 Hz. The viscoelastic properties of the biomaterial were in the range of the viscoelastic properties of human VFLP. The finding of in vitro studies using human VF fibroblast cells confirmed that the composite hydrogels benefits from high cell mobility in the external network and controlled cell adhesion by localized dense microgels. Cytotoxicity tests verified the viability of microgels as the cell substrate medium. Particles with submicrometer diameter were more effective than the larger microgels in establishing cellular adhesion and spreading. Crosslinking of the particles to the external network significantly improved the functionality of the particles as cell substrate medium. The material showed promise for the tissue engineering of VFLP. The composite injectable material was injected into rat vocal fold five days after full LP stripping. Microgels did not induce any immune response from the host. Methods were established using atomic force microscope to measure the elastic properties of the VFLP across different length scales to potentially use in the evaluation of the functionality of the tissue engineered LP constructs. The measured elasticity of rat VF tissue was two orders of magnitude greater than that of human VF tissue. The elastic modulus increased during the remodeling phase after full LP stripping in rat model. The elastic properties of the VF collagen fibrils, the main constituent of VF scar tissue, were measured to be approximately 1 MPa, three orders of magnitude greater than bulk elastic properties of VF tissue.Les troubles de la voix impliquent souvent des blessures physiques et elles ont de graves conséquences émotionnelles, fonctionnelles et économiques. Le présent projet de recherche contribue à l'élaboration d'un biomatériau injectable pour une utilisation potentielle dans le traitement des cicatrices des cordes vocales (VF) lamina propria (LP). Un système de nouvel hydrogel biomimétique, basé sur l'acide hyaluronique (HA) et de la gélatine (Ge), avec une organisation structurelle hiérarchique a été conçu, caractérisé et évalué in vitro et in vivo. Cet hydrogel hiérarchique composite a été constitué de Ge-HA hybride microgels, fabriqué par mini-émulsion de polymérisation de l'eau-dans-l'huile, et intégré dans un réseau secondaire HA.Des expériences ont été réalisées pour étudier l'adéquation du réseau hiérarchique pour l'ingénierie tissulaire VFLP. La microscopie électronique à balayage a confirmé la topographie sphérique des microgels. La microscopie confocale à balayage des microgels, avec fluorescence tachées des molécules de gélatine, a indiqué que les molécules de gélatine distribuaient uniformément à l'intérieur et sur les microgels HA-Ge. Le module de Young de HA-Ge microgels a été mesurée 22 ± 2,5 kPa en utilisant des tests d'indentation. L'ensemble de module d'élasticité en cisaillement a été mesuré 75 ± 15 Pa à la fréquence de 1 Hz. Les propriétés viscoélastiques du biomatériau étaient dans la fourchette basse des propriétés viscoélastiques de VFLP humaine. La constatation d'études in vitro, en utilisant des cellules de fibroblastes humains VF, a confirmé que les composites d'hydrogels bénéficient de la mobilité élevée des cellules dans le réseau externe et de l'adhésion contrôlée des cellules par les microgels denses localisés. Les tests de cytotoxicité a vérifié la viabilité de microgels pour un support substrat cellulaire. Les particules avec un diamètre submicrométrique étaient plus efficaces que les grands microgels en terme de l'adhérence cellulaire et la propagation. La réticulation des particules sur le réseau externe a amélioré de manière significative la fonctionnalité des particules en milieu substrat cellulaire. Le matériau a démontré de la promesse pour le génie tissulaire de VFLP et peut être également utilisé pour d'autres tissus mous. Le matériau composite injectable a été injecté dans les cordes vocales des rats cinq jours après le décapage complet de LP. Microgels n'a pas induit de réponse immunitaire de l'hôte.Des méthodes ont été établies à l'aide de microscope à force atomique pour mesurer les propriétés élastiques de la VFLP à travers différentes échelles de longueur pour éventuellement utiliser dans l'évaluation de la fonctionnalité de l'ingénierie tissulaire de LP construits. L'élasticité mesurée du VF de tissu de rat est de deux ordres de grandeur supérieure à celle du VF de tissu humain. Le module d'élasticité a augmenté pendant la phase de remodelage après le décapage complet de LP dans le modèle de rat. Les propriétés élastiques des fibrilles de collagène VF, le principal constituant du tissu cicatriciel du VF, ont été mesurées à environ 1 MPa, trois ordres de grandeur plus grand que les propriétés élastiques en vrac des tissus VF.
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Běťák, Jiří. "Technology of monofilamentous fibers based on oxidized hyaluronic acid." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2016. http://www.nusl.cz/ntk/nusl-263388.
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Předkládaná dizertační práce se zabývá vývojem technologie výroby nového typu biodegradabilních vláken na bázi oxidované kyseliny hyaluronové. V rámci práce je postupně představován vývoj jednotlivých jednotkových operací výroby, jejichž správné porozumění a schopnost jejich řízení jsou klíčové pro žádaný chod celé vícestupňové technologie. V rámci práce je představen nezbytný vývoj technologického zařízení, průběžně konstruovaného pro účely laboratorního testování a následně až po samotnou linku pro finální výrobu vláken, která byla realizována v roce 2015. V rámci dizertační práce jsou dále navrhovány možnosti dodatečné chemické úpravy vláken s ohledem na zvyšování jejich stability ve vlhkém prostředí. S ohledem na cílené aplikace vláken pro vnitřní chirurgické implantace, jsou v práci vlákna též hodnocena z hlediska jejich materiálové biokomaptibility (toxicity).
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Goetz, Lee Ann. "Preparation and analysis of crosslinked lignocellulosic fibers and cellulose nanowhiskers with poly(methyl-vinyl ether co maleic acid) â " polyethylene glycol to create novel water absorbing materials." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45893.
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The search for cellulosic based products as a viable alternative for petroleum-based products was the impetus for covalently crosslinking lignocellulosic fibers and nanocellulose whiskers with poly(methyl vinyl ether) co maleic acid (PMVEMA) - polyethylene glycol (PEG). The lignocellulosics used were ECF bleached softwood (pine) and ECF bleached birch kraft pulp. This thesis also tests the hypothesis that water absorption and retention can be improved by grafting PMVEMA-PEG to the surface of ECF bleached kraft pulp hardwood and softwood fibers via microwave initiated crosslinking. The crosslinking of the PMVEMA to hardwood and softwood kraft ECF bleached pulp fibers resulted in enhanced water absorbing pulp fibers where the PMVEMA is grafted onto the surface of the fibers. The crosslinking was initiated both thermally and via microwave irradiation and the water absorption and water retention was measured as the percent of grafted PMVEMA. This was the first application of microwave crosslinking of pulp fibers with the goal of creating water absorbing pulp fibers. Ultimately, the water absorption values ranged from 28.70 g water per g dry crosslinked pulp fiber (g/g) to 230.10 g/g and the water retention values ranged from 26% to 71% of the water retained that was absorbed by the crosslinked pulp fibers. The microwave initiated crosslinked fibers had comparable results to the thermally crosslinked fibers with a decreased reaction time, from 6.50 min (thermal) to 1 min 45 sec (microwave).
Cellulose nanowhiskers, crystalline rods of cellulose, have been investigated due to their unique properties, such as nanoscale dimensions, low density, high surface area, mechanical strength, and surface morphology and available surface chemistry. Prior to this study, the crosslinking of cellulose whiskers with the matrix via solution casting of liquid suspensions of whiskers and matrix had not been explored. The hypothesis to be investigated was that incorporating cellulosic whiskers with the PMVEMA-PEG matrix and crosslinking the whiskers with the matrix would yield films that demonstrate unique properties when compared to prior work of crosslinking of PMVEMA-PEG to macroscopic ECF bleached kraft pulp fibers.
Solution cast composites of cellulose nanowhiskers-PMVEMA-PEG were crosslinked at 135 °C for 6.5 min and analyzed for crosslinking, thermal stability, strength and mechanical properties, whisker dispersion, and water absorption and uptake rates. The whisker-composites demonstrated unique properties upon crosslinking the whiskers with PMVEMA-PEG, especially the elongation at break and tensile strength upon conditioning of the final materials at various relative humidities. In addition, the whiskers improved the thermal stability of the PMVEMA-PEG matrix. This is significant as methods of improving processing thermal stability are key to developing new materials that utilize cellulose whiskers, PMVEMA, and PEG. This thesis addresses the hypothesis that cellulose nanowhiskers that are crosslinked with a matrix can create new whisker-matrix composites that behave differently after crosslinking.
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Marcilli, Raphael Henrique Marques 1984. "Filmes de poli(álcool vinílico) reticulados liberadores de NO para o aumento da vasodilatação dérmica." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248517.
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Orientador: Marcelo Ganzarolli de OliveiraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-25T12:07:45Z (GMT). No. of bitstreams: 1 Marcilli_RaphaelHenriqueMarques_M.pdf: 7897278 bytes, checksum: 7868f663066dcea221688ac8dc901af2 (MD5) Previous issue date: 2013
Resumo: Condições fisiológicas associadas à diminuição do nível de óxido nítrico (NO) na vasculatura, como na síndrome de Raynaud e na angiopatia diabética, têm estimulado o desenvolvimento de novos biomateriais capazes de liberar NO topicamente. Neste trabalho efetuamos a modificação do poli(álcool vinílico), PVA, pela sua reticulação química através da esterificação com o ácido mercaptosuccínico. Esta reação permitiu a moldagem de filmes de PVA sulfidrilados (PVA-SH). A calorimetria diferencial de varredura e a difratometria de raios X mostraram que a reação de reticulação suprimiu a cristalização do PVA, levando a um material sem poros, com uma distribuição homogênea de grupos sulfidrila(-SH). Os grupos hidroxila remanescentes na rede de PVA-SH conferiram hidrofilicidade parcial ao material, associada a um grau de intumescimento de 80 a 120 % em meio aquoso. Os filmes de PVA-SH, foram submetidos a uma reação de S-nitrosação dos grupos ¿SH produzindo um PVA contendo grupos S-nitrosotióis (PVA-SNO). Medidas amperométricas e por quimiluminescência mostraram que os filmes de PVA-SNO contém ca. 6 nmols de NO/mg de filme e são capazes de liberar NO espontaneamente após imersão em meio fisiológico. A fluxometria por laser Doppler, usada para medir o fluxo sanguíneo na microcirculação dérmica, permite verificar que a aplicação tópica dos filmes de PVA-SNO hidratados sobre a pele saudável leva a um aumento dependente da dose e do tempo de mais de 5 vezes no fluxo sanguíneo basal em menos de 10 min de aplicação com uma ação prolongada de mais de 4 h durante a aplicação contínua. Estes resultados mostram que os filmes de PVA-SNO podem representar um novo material com potencial para o tratamento tópico no tratamento de desordens microvasculares da pele
Abstract: Pathological conditions associated with the impairment of nitric oxide (NO) production in the vasculature, like Raynaud¿s syndrome and diabetic angiopathy, have stimulated the development of new biomaterials capable of delivering NO topically. In this work, we have modified poly(vinyl-alcohol) (PVA) by chemically crosslinking it via esterification with mercaptosuccinic acid. This reaction allowed the casting of sulfhydrylated PVA (PVA-SH) films. Differential scanning calorimetry and X-ray diffractometry showed that the crosslinking reaction suppressed the crystallization of PVA, leading to a non-porous material with a homogeneous distribution of -SH groups. The remaining hydroxyl groups in the PVA-SH network confered partial hydrophylicity to the material, associated with a swelling degree of 80 to 120 % in aqueous medium. The PVA-SH films were subjected to an S-nitrosation reaction of the SH groups yielding a PVA containing S-nitrosothiol groups (PVA-SNO). Amperometric and chemiluminescence measurements showed that the PVA-SNO films contain ca. 6 nmol NO/mg of film and are capable of releasing NO spontaneously after immersion in physiological medium. Laser Doppler-flowmetry, used to assess the blood flow in the dermal microcirculation, showed that the topical application of hydrated PVA-SNO films on the health skin leads to a dose and time dependent increase of more than 5-fold in the dermal baseline blood flow in less than 10 min with a prolonged action of more than 4 h during continuous application. These results show that the PVA-SNO films may represent a new material with potential for the topical treatment of microvascular skin disorders
Mestrado
Físico-Química
Mestre em Química
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Briceno, Garcia Ruben Dario. "Crosslinking of ethylene copolymers from epoxy chemistry." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0037.
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La plupart des couches d'isolation de câbles pour la moyenne tension "MV" et haute tension "HV" sont fabriquées en polyéthylène réticulé (XLPE) par voie peroxyde. L'impact des sous-produits de réaction sur les propriétés et la nécessité d'une étape de dégazage au cours du processus sont les principaux problèmes liés à cette technologie. Cette étude se concentre sur le développement d'une méthode de réticulation alternative sans les problèmes liés aux sous-produits. Des copolymères d’éthylène/époxy ont été réticulés thermiquement en utilisant un agent aminoacide pour créer des liaisons covalentes entre les fonctions époxydes. L’influence de différents paramètres sur la cinétique de réaction tels que la température de réticulation, les proportions aminoacide/époxy, la taille des particules de l’aminoacide et la teneur en époxy dans les copolymères a été étudiée par techniques de caractérisation telles que : rhéologie dynamique, spectrométrie FTIR, microscopie à balayage électronique et calorimétrie différentielle. En outre, l'étude de la structure du réseau avant et pendant un vieillissement thermique a été effectuée par différentes techniques (mesures de gonflement, spectroscopie FTIR, propriétés de traction et thermoporosimétrie) sur deux types de réseaux : un pré-contraint et un autre non-contraint. Enfin, une caractérisation des propriétés électriques par spectroscopie diélectriques et mesures de claquage électrique a été faite. Les résultats concernant les cinétiques de réaction, les propriétés thermomécaniques et le comportement électrique ont montré que la formulation développée dans cette étude peut être utilisée pour une application de câbleMost of insulation layers of cables for medium voltage “MV” and high voltage “HV” applications are made of crosslinked polyethylene (XLPE) by peroxide technology. The impact of reaction by-products on properties and the consequential need of a degassing stage during the process are the main problems related to this technology. This study focuses on the development of an alternative crosslinking method without by-products issues. Epoxy-ethylene copolymers were thermally crosslinked by using an amino-acid agent to create covalent cross-links between epoxide functions. Influence of several parameters on kinetic reactions such as crosslinking temperature, amino acid/epoxy proportions, size particle of amino acid and epoxy content in copolymers were studied by characterization techniques such as: dynamic rheology, FTIR spectrometry, SEM microscopy and differential calorimetry. In addition, study of the network structure before and during a thermal aging was done on a pre-constrained and a non-constrained network by different techniques (swelling ratio measurement, FTIR spectroscopy, tensile properties and thermoporosimetry analysis). Finally, a characterization of electrical properties by dielectric spectroscopy and breakdown measurements was done. Results related to reaction kinetic, thermo-mechanical properties and electrical behavior have shown that the developed formulation can be used for cable application
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Amiel, Catherine. "Etude expérimentale de la transition sol-gel." Paris 6, 1986. http://www.theses.fr/1986PA066323.
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Nguyen, Van Nga. "Microsphères résorbables pour embolisation et chimio embolisation." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA114808/document.
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L’embolisation thérapeutique est devenu le traitement de choix pour l’hémorragie, les malformations artériovéneuses ou certains types de cancer. Parmi différents agents d’embolisation,les microsphères non dégradables (Embozene®, Bead BlockTM,…) sont les plus utilisées. Leur forme bien sphérique et leur taille calibrée permettent un meilleur ciblage dans les vaisseaux et une bonne qualité de l’occlusion. Dans certains cas cliniques, l’embolisation temporaire, envisageable avec l’utilisation des microsphères résorbables peut être bénéfique pour les patients. Le but du travail réalisé au cours de cette thèse a été le développement de microsphères résorbables satisfaisant les différents critères pour être employées comme matériaux d’embolisation (taille calibrée,biocompatibles, élastique pour être injectée au travers des cathéters mais suffisamment rigide pour résister à la pression sanguine). Dans cet objectif, nous avons développé une méthode de synthèse de microsphères constituées d’hydrogels hydrolysables par polymérisation en suspension. Une large gamme de microsphères ont été synthétisées en modulant la nature du réticulant et/ou la composition des milieux de polymérisation. Les expériences in vitro ont démontré que les microsphères obtenues sont satisfaisantes pour permettre leur injection au travers des cathéters. La dégradation rapide des ponts de réticulation a été confirmée à travers la diminution du module élastique G’ et du pH du surnageant, accompagnée d’une augmentation du taux de gonflement.Malgré une dégradation partielle des microsphères (due à une réaction secondaire formant des liaisons de réticulation non dégradables), le temps de l’hydrolyse a répondu parfaitement au cahier de charges (entre 7 et 49 jours). Des études complémentaires pour optimiser la réaction de polymérisation vont permettre le développement de microsphères totalement dégradablesTherapeutic embolization is nowadays a first line treatment for haemorrhage, arteriovenous malformation or tumors. Among different embolization agents, non degradable microspheres(Embozene®, Bead BlockTM,…) are the most employed thanks to their well calibrated spherical shape which allows good occlusion. In some cases including treatment of uterine fibroids or chemo-sensitive tumors, it may be interesting to achieve a temporary embolization to avoid definitive destruction of the tissue. Temporary embolization would be possible using biodegradable microspheres. The aim of our work was to develop degradable microspheres having all requiredcharacteristics to be used as embolization material (well calibrated in size, biocompatible, rigide enough to resist blood pressure but elastic enough to remain intact during injection through catheter). To this purpose, we have developed hydrolysable hydrogel based microspheres by suspension polymerization. A wide range of microspheres was synthesized by varying the type of crosslinker and composition of the polymerization medium. In vitro test showed that the microspheres have suitable characteristics to pass through catheter. Degradation studies revealed a rapid diminution of G’ modulus and the pH of the supernatants, accompanied by an increase of swelling ratio due to the hydrolysis of the crosslinkings. Although microspheres were not totally degradable as expected (since a side reaction had created non degradable crosslinking during the polymerisation), characterisations showed promising results that the degradation did occur within a suitable time scale requirements for temporal embolization
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Almásyová, Zuzana. "Využití škrobu a glycerinu k přípravě polymerních fólií s řízenou dobou života." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2018. http://www.nusl.cz/ntk/nusl-376797.
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This diploma thesis deals with preparation and testing of biodegradable materials for use in the packaging indrustry. The task of this work is to prepare set of laboratory made films based on wheat starch, glycerol, polyvinyl alcohol with the addition of a suitable additive, which has been selected as citric acid. A suitable composition meeting the requirements of the packaging foils has been found. Quaternary blends from all components achieve the best results. It has been found that citric acid can influence the chemical structure and thus affect the mechanical and thermal properities and also the degree of solubility. The films were characterized in terms of mechanical properities by tensile testing and thermal stability by means of thermogravimetric analysis with respect to the phase structure. The structure was characterized by Fourier transform infrared spectroscopy and confocal laser scanning microscopy. The biodegradability of the film was tested by its solubility in aqueous medium.
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Eriksson, Anna, Viktoria Andersson, Katrin Berezniak, Markus Hall, Victor Håkanson, and Ida Biörs. "Reologi på gelberedningar." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-297837.
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Konsistensen på en gel bestående av tvärbunden hyaluronsyra beror av tre faktorer: total koncentration hyaluronsyra, gelningsgrad och tvärbindningsdensitet. För att utföra detta projekt erhölls tre olika geler med olika tvärbindningsdensitet. Dessa geler späddes dels med lösning av fri, icke tvärbunden, HA från 100 % gelningsgrad till 90 % och 80 %. De olika gelningsgraderna späddes också med natriumkloridlösning från den totala koncentrationen HA, 35 mg HA/g gel, till 25 mg/g och 15 mg/g. Projekts huvudfråga är att kartlägga gelens reologiska egenkaper då både total koncentration HA och gelningsgrad varieras. För att kunna kartlägga detta har en reometer brukats där följande tre tester körts: tidssvep, frekvenssvep och amplitudsvep. Från erhållen data har sedan två parametrar som representerar gelkompositionernas viskösa egenskaper (G'') och elastiska egenskaper (G') observerats. Även mätning av extruderingskraft har genomförts för att dra vidare paralleller och slutsatser mellan extruderingskraften och de reoligiska egenskaperna. Ur resultaten ses att förlusttangenten tenderar att sjunka när gelningsgraden ökar, d.v.s. gelerna blir då mer viskösa och mindre elastiska. Förlusttangenten sjunker även vid ökande total koncentration HA vilket betyder att G’ ökar mer än G’’ i vardera punkt som gör att förlusttangenten minskar.Det gick även att avläsa att de viskösa egenskaperna i gelen ökar då total koncentration hyaluronsyra minskar samt att de viskösa egenskaperna i gelerna minskar vid en sjunkande gelningsgrad. Mellan gelningsgrad 90-100 % och total koncentration HA 25-35 mg HA/g har analyserna som gjorts i detta projekt gett följande slutsatser. Konsistensen på gel A och C är mer påverkade av gelningsgraden än total koncentration HA. För gel B kan ingen dominerande parameter utläsas.The softness of a gel made of crosslinked HA (HA = hyaluronic acid) depends onthree factors. One is the amount of free hyaluronic acid in the gel. Another is thedensity of the crosslinked network, which is the molecular entanglements in the gel.The third is the total concentration of HA. In this project a rheometer is used to measure the rheological properties by runningthe following tests: time sweep, frequency sweep and amplitude sweep. From theobtained data, parameters related to viscous properties (G’’) and elastic properties(G’) of the gels were observed. 27 different compositions of gels with three differentconcentrations (35 mg HA/g, 25 mg HA/g, 15 mg HA/g), three different gel contents(100%, 90%, 80%) and three different densities of crosslinked network (A, B, C) wereanalyzed. To draw further conclusions an analysis of extrusion force was performedas well. The results from the frequency sweeps show that the loss tangent for a gel increasedas the total concentration of HA was reduced and that the loss tangent for a gelincreased as the gel content was decreased. This indicates that the gels become moreviscous when either the concentration of HA or the gel content was decreased. Anincrease in concentration of HA results in an increase of G' and an increase of gelcontent also results in an increase of G'. The results from the amplitude sweeps showthat xG' (xG' = storage modulus at the crossover point between G' and G'') increasesas either the concentration of HA or the gel content is increased. For xStrain (xStrain= deformation of the gel at the crossover point) and xStress (xStress = the stressapplied to the gel at the crossover point) no clear trend can be seen regarding the gelcontent. But an increase in concentration of HA results in an increase of both xStrainand xStress. The results from the analysis of extrusion force show that an increase intotal concentration HA increases the force.
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Rabie, Ahmed 1978. "Reaction of Calcite and Dolomite with In-Situ Gelled Acids, Organic Acids, and Environmentally Friendly Chelating Agent (GLDA)." Thesis, 2012. http://hdl.handle.net/1969.1/148152.
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Well stimulation is the treatment remedy when oil/gas productivity decreases to unacceptable economical limits. Well stimulation can be carried out through either "Matrix Acidizing" or fracturing with both "Hydraulic Fracturing" and "Acid Fracturing" techniques. "Matrix Acidizing" and "Acid Fracturing" applications involve injecting an acid to react with the formation and dissolve some of the minerals present and recover or increase the permeability. The permeability enhancement is achieved by creating conductive channels "wormholes" in case of "Matrix Acidizing" or creating uneven etching pattern in case of "Acid Fracturing" treatments.
In both cases, and to design a treatment successfully, it is necessary to determine the distance that the live acid will be able to penetrate inside the formation, which in turn, determines the volume of the acid needed to carry out the treatment. This distance can be obtained through lab experiments, if formation cores are available, or estimated by modeling the treatment. The successful model will depend on several chemical and physical processes that take place including: the acid transport to the surface of the rock, the speed of the reaction of the acid with the rock, which is often referred to as "Reaction Rate", and the acid leak-off. The parameters describing these processes such as acid diffusion coefficient and reaction kinetics have to be determined experimentally to ensure accurate and reliable modeling.
Hydrochloric acid and simple organic acids such as acetic and citric acids have been used extensively for stimulation treatments. The diffusion and reaction kinetics of these acids, in a straight form, were investigated thoroughly in literature. However, solely these acids are used in a simple form in the field. Acid systems such as gelled, crosslinked gelled, surfactant-based, foam-based, or emulsified acids are used to either retard the reaction rate or to enhance acid diversion. Literature review shows that additional work is needed to understand the reaction and report the diffusion and kinetics of these systems with carbonate. In addition, a new chelating agent (GLDA) was recently introduced as a stand-alone stimulating fluid. The kinetics and the mass transfer properties of this acid were not studied before.
Therefore, the objective of this work is to study the reaction of different acid systems with calcite and dolomite and report the mass transport and kinetic data experimentally. Lactic acid, a chelating agent (GLDA), and in-situ gelled HCl-formic acids were investigated in this study. In some cases, rheology measurements and core flood experiments were conducted. The data were combined with the reaction study to understand the behavior of these acids and examine their efficiency if injected in the formation.
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Doneanu, Catalin E. "Mass spectrometric analysis of UV-crosslinked protein-nucleic acid complexes." Thesis, 2002. http://hdl.handle.net/1957/31851.
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張晉瑋. "Porous Scaffolds Synthesized from Calcium Phosphates Coating Crosslinked Hyaluronic Acid-Gelatin." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/15648092481950789044.
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Chung, Wen-Mei, and 鍾文梅. "Study of EDC-crosslinked polygalacturonic acid membrane for the feasibility of." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/03579237099146057638.
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碩士國立陽明大學
醫學工程研究所
97
We have previously developed a postsurgical anti-adhesion membrane by crosslinking polygalacturonic acid (PGA) with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC). As a continuous effort to explore the potential biomedical application of PGA, we have fabricated and characterized four different types of polymeric membranes by crosslinking PGA with 15 mM or 50 mM EDC in the aqueous solutions of 80% ethanol and 80% acetone, separately. The crosslink was confirmed by a new C=O absorption appeared near 1800 cm-1, probably by anhydride bonding. In addition, a narrower absorption peak (3200-3400 cm-1) was observed for the crosslinked membrane as compared with the wider range of 3000-3500 cm-1 found in the PGA membrane before EDC treatment, indicating a portion of the PGA hydroxy groups was consumed by the crosslinking reaction. All of the EDC-crosslinked PGA membranes had a transmission efficiency of 50% - 70% to visible light. The four different crosslinked PGA membranes were implanted subcutaneous in mice and retrieved for histological examination 14 days after implantation. The PGA membranes crosslinked with 15 mM EDC in both aqueous solutions of ethanol and acetone appeared to be more fragile as compared with those crosslinked at 50 mM EDC, which maintained integrity of the implanted membranes. All PGA membranes effectively prevented the post-surgical adhesion in the abdominal cavity. PGA membrane of 15 mM EDC treatment in ethanol was completely degraded in 14 days after implantation, whereas all other three PGA membranes remained intact. Inflammation and angiogenesis were also observed around the implanted sites. Long-term in vivo implant study is suggested to further study the biocompatibility of these PGA membranes.
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CHJANG, Ta-Wei, and 江大威. "Antibacterial activity and cytocompatibility of chitosan/gelatin membranes crosslinked by gallic acid." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/93306020121253762153.
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碩士亞東技術學院
材料應用科技研究所
98
This research pertains to blend the gallic acid with chitosan and gelatin and cast into membranes. chitosan/gelatin were blended with gallic acid as natural nontoxic crosslinking reagent to replace toxic glutaraldehyde crosslinking reagent which was currently applied in biomaterials and fibers. Chitosan (C), gelatin (G), chitosan/gelatin (C/G), chitosan/ 0.1% gallic acid/ gelatin (C/0.1%GA/G) and chitosan/ 0.1% gultaraldehyde/ gelatin (C/0.1%GH/G) of five membranes were prepared in this article. Those membranes were examined by Fourier transform infrared spectroscopy (FT-IR) and end group test method to determine the chemical structures and crosslink degree. The hydrophilicity of membranes were evaluated by water contact angle and swelling ratio. The antibacterial activities and cytocompatibility were examined for the purpose of application in biomaterials and textiles. The results of water contact angle and swelling ratio showed that, the membranes blended with gelatin - chitosan/gelatin (C/G), chitosan/ 0.1% gallic acid/ gelatin (C/0.1%GA/G) and chitosan/ 0.1% gultaraldehyde/ gelatin (C/0.1%GH/G)were more hydrophilic than chitosan membrane. The antibacterial activities of above those membranes against Staphylococcus aureus were also evaluated in this research. The results showed the antibacterial activity of chitosan/ 0.1% gallic acid/ gelatin (C/0/1%GA/G) blended membrane against Staphylococcus aureus was higher than the other two blended membranes. The cytocompatibility was also investigated in-vitro with fibroblast proliferation by MTT colorimetricy assay. The results showed that, those membranes blended with gelatin - chitosan/gelatin(C/G), chitosan/ 0.1% gallic acid/ gelatin (C/0/1%GA/G) and chitosan/ 0.1% gultaraldehyde/ gelatin (C/0/1%GH/G) could effectively promote the growth of cell as chitosan (C) membrane.
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Chen, Yi-Chung, and 陳怡仲. "Removal Nickel ion in Water by γ-Polyglutamic acid Crosslinked with Bagasse." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/10677040415562381716.
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碩士國立高雄師範大學
化學系
99
A novel metal adsorbent has been synthesized by crosslinking γ-polyglutamic acid with bagasse. This adsorbent contains multiple fuctional groups that can be used as chelating agent to remove nickel ion in water. This material was prepared by oxidizing hydroxyl groups of cellulose to aldehyde using sodium periodate and attachment of γ-PGA to aldehyde via Schiff base. The steric hinderance could be the factor to hinder γ-PGA from attaching to aldehyde and the maximum crosslinking degree was formed by reacting 100 mL of 200 mg/L γ-PGA with 2.5 grams of bagasse. The study is aim to use four different factors to obtain the maximum capacity of adsorbent of nickel ion and find out the best desorption method. The maximum nickel sorption was obtained for pH 9 and contacting 45 minutes. The isotherm data at pH 9 were well described by a linear form of the Langmuir equation and the equation showed the maximum adsorption capacity was 4.695 mg/g and adsorption constant was 1.454 L/mg. The sorption of mobile phase was not good as it of static immersion. Desorption by 1 M NaOH was much better than it by 1M HCl and could give a resorption of 0.236 mg Ni2+/0.1 g adsorbent.
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Ramos, Nuno José Prego. "Crosslinked Hyaluronic Acid nanoparticles as delivery vehicles for dendritic cell-targeted vaccines." Master's thesis, 2016. http://hdl.handle.net/10362/17792.
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RESUMO: O sistema imunitário tem sido o alvo dos mais recentes avanços no tratamento do cancro. Imunoconjugados, terapias direcionadas e imunoterapias são as classes de medicamentos mais investigados no tratamento do cancro, com muitos candidatos a fármacos atualmente em fase de desenvolvimento pré-clínico e fase final de desenvolvimento clínico. Terapias focadas em células dendríticas (CDs) são muito promissoras, uma vez que as CDs são células apresentadoras de antigénios, o que as transforma em alvos interessantes para controlar a resposta imune aquando da presença de células cancerígenas.
Considerando que os antigénios sobre expressos pelas células cancerígenas podem ser apresentados às CDs induzindo uma resposta imune protetora contra o cancro, é fundamental investigar um veículo de transporte com afinidade para as DCs, bem como definir o biomaterial certo para transportar os antigénios (ou frações do antigénio) para o ambiente circundante, onde as CDs existem e onde pode ser induzida a sua maturação.
Hipotetizámos o desenvolvimento de um sistema de nanopartículas para a entrega e direcionamento de um candidato terapêutico, nomeadamente um antigénio ou suas frações, numa formulação utilizando um polímero biodegradável, um veículo não tóxico que pudesse melhorar a biodisponibilidade do agente biológico, aumentando as capacidades de segmentação de uma formulação farmacêutica. O ácido hialurónico (AH) foi o biopolímero escolhido devido às suas propriedades viscoelásticas, a sua afinidade para os recetores de superfície das CDs, como o CD44 e para os recetores TLR induzindo assim a sua ativação e consequente migração para os linfócitos T nos gânglios regionais.
O principal objetivo desta tese foi encontrar um método eficaz de produzir nanopartículas de AH através de um novo método de reticulação, procedendo à sua caracterização por Nanoparticle Traking Analysis, obtendo informação relativa à dimensão das partículas, concentração e distribuição das dimensões. A toxicidade do sistema de nanopartículas foi avaliada posteriormente utilizando PBMCs e analisada por câmara de Neubauer e citometria de fluxo.
A nossa pesquisa demonstra que é possível produzir nanopartículas de AH de acordo com o método proposto, e que este sistema não parece induzir qualquer efeito citotóxico, tal como demonstram os resultados dos ensaios realizados.------------------------------------------------------------------- ABSTRACT: The immune system has been the target of the most recent advances in cancer treatment. Immunoconjugates, targeted therapies and immunotherapies are the most researched class of products for the treatment of cancer with many drug candidates currently in pre-clinical and late clinical stages of development. Therapies focused on Dendritic cells (DCs) are very promising since DCs are antigen presenting cells and that turns them into interesting targets for controlling the immune response in the presence of cancer cells.
Considering that antigens overexpressed by cancer cells could be presented to DCs inducing a protective anticancer immune response, it is important to assess the vehicle with affinity to DCs, as well as finding the right biomaterial to transport the antigens (or fractions of the antigen) to the surrounding environment where DCs can be found and where maturation can be induced.
We have hypothesized the development of a nanoparticle system for the delivery and targeting of the drug candidate, mainly an antigen or fractions thereof, which can be formulated using a biodegradable polymer, a non-toxic vehicle that can improve bioavailability of the biologic agent, increasing the targeting capabilities of a pharmaceutical formulation. Hyaluronic acid (HA) was the biopolymer chosen due to its viscoelastic properties, affinity to the surface receptors of DCs such as CD44 and to Toll-like receptors inducing migration and activation of T lymphocytes in the region nodes.
The main goal of this thesis was to find an effective method of producing HA nanoparticles through a novel crosslinking method, characterizing the nanoparticles by Nanoparticles Tracking Analysis, measuring particles size, concentration and size distribution. Later, the toxicity of the nanoparticles system was evaluated using Peripheral Blood Mononuclear Cells (PBMCs) upon nanoparticles presentation (by Neubauer chamber and Flow cytometry analysis).
Our findings show that it is possible to produce nanoparticles according to the proposed methodology and that the nanoparticulate system does not induce any cytotoxic activity as shown in the assays performed.
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"Theoretical investigation of cisplatin-deoxyribonucleic acid crosslink products." 2004. http://library.cuhk.edu.hk/record=b5892233.
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Fu Annie Yuen Yee.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.
Includes bibliographical references (leaves 97-108).
Abstracts in English and Chinese.
ABSTRACT (ENGLISH) --- p.iii
ABSTRACT (CHINESE) --- p.iv
ACKNOWLEDGMENTS --- p.v
TABLE OF CONTENTS --- p.vi
LIST OF FIGURES --- p.ix
LIST OF TABLES --- p.xi
Chapter CHAPTER ONE: --- BACKGROUND INFORMATION --- p.1
Chapter 1.1 --- Introduction --- p.1
Chapter 1.2 --- Deoxyribonucleic Acid --- p.1
Chapter 1.2.1 --- Nomenclature and Symbols --- p.1
Chapter 1.2.2 --- Torsion Angles --- p.4
Chapter 1.2.3 --- Conformation --- p.5
Chapter 1.3 --- DNA Studies --- p.8
Chapter 1.3.1 --- Base --- p.8
Chapter 1.3.2 --- Base-Pair --- p.10
Chapter 1.3.3 --- Summary --- p.11
Chapter 1.4 --- Cisplatin Studies --- p.11
Chapter 1.4.1 --- Reaction --- p.12
Chapter 1.4.2 --- Cisplatin-DNA Products --- p.14
Chapter 1.4.3 --- Summary --- p.15
Chapter 1.5 --- Scope of This Thesis --- p.15
Chapter CHAPTER TWO: --- COMPUTATION AND METHODOLOY --- p.17
Chapter 2.1 --- Introduction --- p.17
Chapter 2.2 --- Hartree-Fock Approximation --- p.17
Chapter 2.3 --- Geometry Optimization --- p.18
Chapter 2.4 --- Molecular Orbital (MO) Calculation --- p.20
Chapter 2.5 --- Verification of Methodology --- p.20
Chapter 2.5.1 --- Backbone Torsion Angles --- p.20
Chapter 2.5.2 --- N7-N7 Distance --- p.26
Chapter 2.5.3 --- Location of HOMO --- p.30
Chapter 2.6 --- Summary --- p.31
Chapter CHAPTER THREE: --- UNDERSTANDING OF THE CISPLATIN-DNA CROSSLINKS --- p.33
Chapter 3.1 --- Introduction --- p.33
Chapter 3.2 --- MO Analysis --- p.33
Chapter 3.3 --- Potential Binding Sites of DNA --- p.34
Chapter 3.3.1 --- "1,2-d(GpG) Intrastrand Crosslink" --- p.40
Chapter 3.3.2 --- "l,2-d(ApG) Intrastrand Crosslink" --- p.40
Chapter 3.3.3 --- "l,3-d(GpXpG) Intrastrand Crosslink" --- p.41
Chapter 3.3.4 --- d(GpC)d(GpC) Interstrand Crosslink --- p.41
Chapter 3.3.5 --- d(GpXpC)d(GpXpC) Interstrand Crosslink --- p.41
Chapter 3.3.6 --- Summary --- p.42
Chapter 3.4 --- Empirical Selection Rule --- p.44
Chapter 3.4.1 --- Convention --- p.44
Chapter 3.4.2 --- Selection of Potential HOMO Location (or Active Site) --- p.45
Chapter 3.4.3 --- Selection of Potential HOMO-Nearby Active Site --- p.47
Chapter 3.4.4 --- Applications --- p.48
Chapter 3.5 --- Cisplatin --- p.51
Chapter 3.6 --- Cisplatin-DNA Crosslinks --- p.52
Chapter 3.6.1 --- "l,2-d(GpG) and l,2-d(ApG) Intrastrand Crosslinks" --- p.52
Chapter 3.6.2 --- "l,2-d(ApG) versus l,2-d(GpA) Intrastrand Crosslinks" --- p.53
Chapter 3.6.3 --- "l,3-d(GpXpG) Intrastrand and d(GpXpC)d(GpXpC) Interstrand Crosslinks" --- p.54
Chapter 3.6.4 --- Platination at Terminal Positions --- p.55
Chapter 3.7 --- Structural Parameters --- p.59
Chapter 3.7.1 --- Optimized Geometries --- p.59
Chapter 3.7.2 --- DNA Sequences from PDB --- p.67
Chapter 3.7.3 --- Backbone Torsion Angles --- p.70
Chapter 3.8 --- Summary --- p.70
Chapter CHAPTER FOUR: --- CONCLUDING REMARKS --- p.72
APPENDIX I BACKBONE TORSION ANGLES AND SUGAR RING CONFORMATION OF THE OPTIMIZED GEOMETRIES --- p.74
APPENDIX II BACKBONE TORSION ANGLES OF THE EXPERIMENTAL SEQUENCES FROM NUCLEIC ACID DATABASE (NDB) --- p.82
REFERENCES --- p.97
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Shen, Pei-Shan, and 沈貝珊. "Antibacterial activity and cytocompatibility of water–soluble derivatives of chitosan crosslinked by gallic acid." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/f777kk.
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碩士國立臺灣科技大學
材料科學與工程系
99
Chitosan was modified with glycidyl trimethyl ammonium chloride (GTMAC) and glycidy methyl diallyl ammonium salt (GMDAS) to produce two water soluble derivatives, N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) and N-(2-hydroxyl) propyl-3-methyl diallyl quaternary ammonium salts of chitosan (HMDC). Furthermore, HTCC and HMDC were modified with gallic acid to produce two water soluble derivatives, HTCC-GA and HMDC-GA. In the first part of this study, HTCC, HTCC-GA, HMDC and HMDC-GA were examined using FT-IR to determine the chemical structures. The hydrophilicity was evaluated based on the water contact angle, swelling ratio, and biodegradability. The surface charge was determined using the zeta potential. The antibacterial activity, and cytocompatibility were evaluated for the applications as wound covering material.
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Lee, Chin-Shih, and 李經世. "Removal of iron ion in aqueous solution by bagasse crosslinked with γ-polyglutamic acid." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/48229994445255730698.
Full textAbstract:
碩士國立高雄師範大學
化學系
99
γ-PGA is natural biopolymer.γ-PGA is harmless for environment and good effect on adsorptive for heavy metals. And it can be used as the absorbent to absorb heavy metals in water. The experiment used the properities of γ-PGA and tryed to use the product of absorbent with γ-PGA crosslined with bagasse. Besides the experiment investigates how the absorbent absorb the iron ion in water. And it finds out the best absorption under different conditions and provides a new option for purification of water in environment protection. The experiment finds out the using γ-PGA to crossline bagasse as the absorbent absorb iron ion that fits in with Langmuir’s Mono Molecule Layer Absorption. When water is filtered at pH=6 that it has the best effecet to remove the iron ion in water.
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Horng, Ming Kae, and 洪明凱. "The Synthesis and Application of Maleamic Acid Based Biheterofunctional Crosslinkers." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/66928041370830337454.
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Gafken, Philip R. "Characterization of UV-crosslinked protein-nucleic acid interfaces by Maldi MS and ESI MS/MS." Thesis, 2000. http://hdl.handle.net/1957/32805.
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Jheng, Wu-Huei, and 鄭武輝. "Preparation and Proton-conducting Properties of Crosslinked Imide/Siloxane Hybrid Membranes Grafted with Sulfonic Acid." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/85663087232058477823.
Full textAbstract:
碩士國立成功大學
化學工程學系碩博士班
96
A new type of hybrid proton-conducting membranes with crosslinked polysiloxane framework was designed and prepared via sol-gel approach based on poly(styrene-co-maleic anhydride) modified with 2-aminoethanesulfonic acid sodium salt (AESA-Na) and Aminopropyltriethoxysilane (APTES). The number density of the pendant of sulfonate group was controlled by the ratio of AESA-Na to APTES. The resulted membranes own good mechanical strength. The structural characterizations of these membranes were confirmed by FT-IR and solid-state 13C and 29Si NMR spectra. All of these membranes exhibit a wholly amorphous morphology, perform adequate oxidative stability in Fenton’s reagent at 80 �aC for 1 h, and show two step of weight loss from 350 �aC, indicating their good thermal stability. The polysiloxane network is contributive to the increase in bound water degree and decrease in methanol permeability. The HPM sample with 1.3 theoretical mequiv SO3H/g reaches the proton conductivity of 0.0570 Scm-1 at 30 �aC and 0.125 Scm-1 at 70 �aC, respectively. Moreover, it also has low methanol permeability of 7.76×10-7 cm2s-1 at 30 �aC, and yield maximum power density of 24.9 mW cm-2 at 60 �aC. The HPM performed slightly better than Nafion 117 (proton conductivity = 0.0541 Scm-1, methanol permeability = 2.51×10-6 cm2s-1 and power density = 21.1 mW cm-2) under the same conditions.
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高健文. "Removal of copper(II) ion in water by γ-polyglutamic acid crosslinked with magnetite nanoparticles." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/dp86xv.
Full textAbstract:
碩士國立高雄師範大學
物理學系
102
In this research﹐an adsorbent was synthesized by crosslinking γ-polyglutamic acid (γ-PGA) with magnetite nanoparticles (MNPs)to be used as a chelating agent for removing copper ion in water,and to examine the reabsorption. Several environments with different experiment factors except to chang temperature were designed to compare the efficiency of absorption,such as pH variation、0.1 g adsorbent with different concentrations of copper ion solution.I also discuss which model is in adsorption of isotherm and kinetic theory. The maximum copper ion adsorption was obtained at pH 5.3 due to the fact that γ-PGA has different structures at different pH value；Adsorption capacity (4.03 mg/g and 80.6% absorptivity) makes me choose 0.1 g adsorbent with 20 ppm copper ion solution﹐if we considered the economic benefits,pseudo-second order equation and Langmuir isotherm model were both confirmed because of the high coefficient of correlation；Desorption by 1 M NaOH was much better than processed by 1M HCl,which could give a resorption of 3.91 mg Cu2+/ g adsorbent, the result can correspond with the purpose of recycling.
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Lin, Yi-Hsiang, and 林意翔. "Preparation and antibacterial properties of poly(lactic acid) composites filled with ionic-crosslinked chitosan particles." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/44862458806549936240.
Full textAbstract:
碩士淡江大學
化學工程與材料工程學系碩士班
102
Biodegradable polymers, also known as green plastics, can completely decompose into water and carbon dioxide under appropriate environmental conditions which consequently reduces the harm to the environment. Among many biodegradable polymers in the market, the most widely used is poly(lactic acid) (PLA), which has good mechanical rigidity and thus can be used in the cutlery, packaging materials and biomedical materials. On the other hand, chitosan (CS) is a natural polysaccharide polymer and is recognized as a non-toxic, antibacterial, biocompatible and biodegradable material. It can be used in food engineering and biomaterials. In this study, chitosan ionic-crosslinking particles (CS-TPP) was added into PLA films to render antibacterial properties for the use in food packaging materials. The CS-TPP particles in submicron size were prepared by ionic crosslinking the CS with tripolyphosphate (TPP) and added into the PLA to prepare antimicrobial and biodegradable films. In addition to the mechanical properties measured by tensile test, the initial modulus between 1.65 to 1.73 GPa. It not evident. Thermodynamics measured by DSC and TGA. Distribution of CS-TPP particles in the PLA matrix was evaluated by scanning electron microscopy. It can observe that there had no cluster in PLA matrix. The antibacterial properties of the prepared PLA composite films on two bacteria, Escherichia coli and Staphylococcus aureus, were also tested. When CS-TPP content 4 wt%, the antibacterial properties of Escherichia coli and Staphylococcus aureus were 39% and 13%. When CS-TPP content 8 wt%, the antibacterial properties of Escherichia coli and Staphylococcus aureus were 43% and 29%. Although emulsified PLA can degradable by enzyme, the degradability of PLA films by enzyme is not good.
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Chih-HsienShih and 施志憲. "Syntheses and Proton-conducting Properties of Crosslinked Imide/Siloxane/Phenyl-Oxide Hybrid Membranes Containing Sulfonic Acid." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/88501925810871095958.
Full textAbstract:
碩士國立成功大學
化學工程學系碩博士班
98
A new series of hybrid proton-exchange membranes with polysiloxane framework was designed and prepared based on poly (styrene-co-maleic anhydride, SMA) where incorporated with sodium 2-aminoethanesulfonate (AESA-Na) and bis-(aminoprophyl) polydimethylsiloxane (X-22). In this system, we added a new diamino compound of 1, 4-bis (4-aminophenoxy) benzene (BAPB) as cross-linker to increase the proton conductivity. It was found that introducing BAPB could enhance the film forming ability, increase IEC value to 1.83, and also increase the thermal stability and oxidative stability. For SAXB-y-90/10 system, the proton conductivity (under fully-hydrated) is about 3.6 × 10-2 Scm-1 to 7.7 × 10-2 Scm-1, it also shows the highest IEC value (1.83). TEM analysis can obtain the cross-section morphology, it was found that the higher IEC value causes formation of such higher ionic cluster density than lower IEC value (better connection of proton transport pathway). For SAXB-2.0-90/10, single cell test shows performance at 80 degrees Celsius of 23 mW/cm2.
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Kuo, Chai-Wei, and 郭家維. "Study of Alginate Hydrogel Crosslinked with γ-Polyglutamic Acid and Blended with Temperature-Responsive Pluronic F127." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/b68gy5.
Full textAbstract:
碩士國立臺灣科技大學
高分子系
95
In this study, the improved mechanical properties, swelling behavior and affect of blood-compatibility was investigated by an novel of hydrogels synthesized technique by cross-linking calcium poly(γ-glutamic acid) (γ-PGA) and alginate sodium with blended of various ratios nonionic surfactant Pluronic F127 with temperaturesensitive. Results showed that the addition of Pluronic F127 can not only improve mechanical properties efficiently but also influence the temperature- sensitive swelling of hydrogels, it also exerted minor effect on the pH-sensitive swelling and promote anticoagulation. As to an dream of biomaterials should have good biocompatibility, blood-compatibility, biodegradability and outstanding mechanical properties, this research can say that succeed in being close to the predeterminated target.
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Huang, Tsung-Te, and 黃宗德. "Removal of copper(II) ion in aqueous solution by cotton fiber crosslinked with gamma-polyglutamic acid." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/75703532607813142266.
Full textAbstract:
碩士國立高雄師範大學
化學系
99
This study emphasizes on the adsorption of copper ions by biosorbent which was prepared from the natural cotton fiber chemically crosslinked with poly glutamic acid (γ-PGA). After experimental demonstration, the natural cotton chemicaly modificated has better adsorption of copper ions than it without the chemical modification when the temperature won’t change anymore, especially the best is the poly glutamic acid (γ-PGA) concentration of 200 mg / L . When the concentration of copper ions is higher, the adsorption rate of the adsorbent decreased , but the absorption capacity increased. About the mass of the adsorbent, 0.1 g has the best adsorption capacity (8.49 mg /g) for 50 ppm copper ions in solution. About the adsorption method, the result of leaching ten times by SPE closes to stirring 2 hr and has more time-saving advantages. About the adsorption conditions, the results of about pH5.5 show the best and the lower pH have the worse adsorption ability. In the isothermal adsorption experiment , I obtains n=2.4582>1 by Freundlich isothermal adsorption equation and that expresses the favorable adsorption. I get the eqilibrium constant RL=0.2668 ~ 0.0494 from Langmuir equation and expression the isothermal adsorption is favorably. According to the R2=0.9375 from Freundlich isothermal and the R2=0.998 from Langmuir isothermal adsorption, that demonstrated this research conforms to the model of Langmuir isothermal adsorption. In Dynamics adsorption, confirmed the largest adsorptive capacity is 2.79 mg/g from pseudo-first order and 4.352 mg/g from pseudo-second order. This research conforms to pseudo-second order because R2=0.9965 of pseudo-second order. is larger than R2=0.9539 of pseudo-first order. It also demonstrated that the reaction rate is affected by the concentration of the reactant.
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Chung, Yi-Lung, and 鍾易龍. "A study of adipic acid dihydrazide crosslinked oxi-hyaluronic acid hydrogel combined with gelatin microparticle as scaffold for articular cartilage tissue engineering." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/w37ga4.
Full textAbstract:
碩士國立臺北科技大學
生化與生醫工程研究所
102
In recent years, the cartilage injury repair has been a popular topic in regenerative medicine. The cartilage has limited self-repair capacity due to lack of nerves and blood vessels in the articular cartilage. So far, some treatment surgeries have been developed in clinic; however, some limitations still exist such as fibrocarilage formation. Until the tissue engineering is well developed, cartilage repair will reach to a higher level. To date, the most suitable bioscaffold for chondrocytes in the cartilage repair is still not finding. In this study, we have developed the hyaluronic acid-based hydrogel and incorporated it with gelatin particles to evaluate the possibility as the bioscaffold for cartilage tissue engineering. We expected the bioscaffold not only mimic ECM functions, but also have the ability to promote chondrocytes proliferation and maintain the phenotype. In this study, the oxidized hyaluronic acid with aldehyde functional groups prepared by sodium periodate was crosslinked by adipic acid dihydrazide (ADH) to form hydrogel. The gelatin was modified by glutaraldehyde and proanthocyanidins crosslink agents to form gelatin particles. Then we incorporated hydrogel and particles as the bioscaffold. To investigate the characterization of bioscaffold, the IR, SEM, EDS, degradation time and biocompatibility test were evaluated. The gene expression for chondrocytes encapsulated in hydrogel was also evaluated by real-time PCR. The results shown the microparticles had uniform pore size about 80-150 μm and the crosslinking index remained above 90%.The hydrogel combined with microparticles through WST-1, LDH and Live/Dead analysis are non-cytotoxicity; also has good results in SEM analysis, histological evaluation, GAGs content, gene expression and tissue culture assay. Importantly, the construct also promoted chondrocytes synthesis of COL2A1, AGN, and SOX-9 mRNA. In this study, we prepared hyaluronic acid-based hydrogel combined with gelatin particles as chondrocytes bioscaffold. The oxidized hyaluronic acid /ADH crosslinked hydrogel can be prepared in a liquid form at room temperature and easily mixed with gelatin particles and chondrocytes. These preliminary data indicate that the hydrogel and gelatin particles have good biocompatibility, and contribute chondrocytes maintain gene expression. Based on the results, the oxi-HA hydrogel combined with gelatin particles may have potential uses in cartilage tissue engineering applications.
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Yang, Chin-Yo, and 楊進有. "Use TPP/genipin co-crosslinked chitosan gel beads to adsorb the phytic acid of soybean whey solution." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/97425649245773840739.
Full textAbstract:
碩士國立臺灣海洋大學
食品科學系
98
The object of this study is to investigate the characterization of different type of TPP/genipin co-crosslinked chitosan beads and choose an appropriate kind of chitosan bead to carry out the study of adsorption isotherm for phytic acid. Finally, finding the optimum condition for selectively adsorbed of phytic acid from soybean whey, and improving the utilization of soybean whey. The chitosan-based networks of gel beads were prepared with degree of deacetylation of 80% and molecular weight of 900 kDa chitosan. The characterization of chitosan beads were different with to prepared in different pH (2.0, 3.0, 5.0, 7.0 and 9.0). The crosslinking degree and size of beads were decreased with increasing pH value. The degree of crosslinking and the size of chitosan beads were between 80.14% to 59.22% and 2.38 to 1.94 mm, respectively. The chitosan beads co-crosslinked at pH 7.0 had better breaking force, deformation degree of breaking and gel strength, the each of value was 5.38 g, 1.31 mm and 7.08 g•mm, respectively. The phytic acid was adsorbed with different type of chitosan beads to get equilibrium concentration at 24 hours. The amount of phytic acid was adsorbed by co-crosslinked chitosan beads were increasing with decreasing pH value. The TPP/genipin co-crossliked chitosan bead prepared in pH 7.0 was be the adsorbent to adsorb phytic acid, because its mechanical strength and adsorption capacity was good. The parameters studied include the effects of pH, treatment time and the initial concentrations by batch method. The maximum monolayer adsorption of the chitosan beads was 12.24 mg g-1 at pH 2.0, 35℃ and 24 h. The results obtained from equilibrium adsorption studies were fitted in Langmuir adsorption model but not in Freundlich adsorption model, and the model parameters have been evaluated. The equilibrium parameter (KR) indicated that the process of adsorption was favorable. The dynamical data fit well with the second-order kinetic model. The adsorption capacity increases largely with decreasing solution pH and temperature or with increasing initial phytic acid concentration. The adsorption of phytic acid on the chitosan bead co-crosslinked at pH 7.0 was spontaneous and an exothermic process, and accompany of decreasing randomness. The activation energy of adsorption and desorption were 55.77 kJ mol-1 and 71.51 kJ mol-1, respectively. In order to desorb phytic acid from the surface of co-crosslinked chitosan bead into solution which the solution condition need be changed. At pH 2.0 and 25℃, the chitosan beads co-crosslinked at pH 7.0 could selectively adsorb phytic acid from soybean whey solution, and the adsorption rate was 30.23%. At pH 9.0 and 25℃, the chitosan beads co-crosslinked at pH 7.0 could desorb the absorbed phytic acid efficiently, the desorption rate was 93.98%.
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Chang, Yen-Ting, and 邱彥廷. "Removal of Nickel(Ⅱ) ion in Aqueous Solution by cotton fiber crosslinked with γ-poly glutamic acid." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/58636753651321954780.
Full textAbstract:
碩士國立高雄師範大學
化學系
99
This study investigates the adsorption of nickel ion in aqueous solution by cotton fiber crosslinked with γ-poly glutamic acid.I use the special approach to obtain sorption of heavy metals utilizing poly-glutamic acid covalenily attached to natural fiber. γ-Poly glutamic acid produced by microorganism is a new biodegradable polymer.Because each monomer of γ-poly glutamic acid has amidogen group (NH2) and carboxyl group (COOH)，γ-poly glutamic acid has good adsorptive capacities for heavy metals. It also proposes a pretreatment method for analyzing water quality and an equipment to treat industrial sewage and also to the recovery of valuable metals from solutions in the future. Experimental results were found that the effects of initial nickel concentration, initial pH,γ-PGA dosage and adsorption time,poly-γ-glutamic acid had the best absoption capacity when solution's pH value=8. Compared with the Langmuir Isothem curve R2=0.9934 and the Freundlich Isothem curve R2=0.9051 may know that, the poly-γ-glutamic adsorption experiment is partial in the Langmuir Isothem theory. The maximum capacities were as high as 3.96 mg/g with Ni sorption on special cellulosic matter.
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Chang, Yu-Lung, and 張祐朧. "Selective adsorption of trypsin inhibitor, lectin and phytic acid from soybean whey by chitosan/tripolyphosphate/genipin co-crosslinked beads." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/74344133820169445068.
Full textAbstract:
碩士國立臺灣海洋大學
食品科學系
100
vii Abstract The purpose of this study is selectively adsorbed trypsin inhibitor, lectin and phytic acid form soybean whey by chitosan/tripolyphosphate (TPP)/genipin co-crosslinked beads. The chitosan beads (CB5, CB7, CB9) were co-crosslinked with TPP/genipin solution at pH 5.0, 7.0 and 9.0, respectively. At 5, 15 and 25℃,these co-crosslinked chitosan beads were adsorbed trypsin inhibitor, lectin and phytic acid from soybean whey solutions in pH 2.0-6.0 solutions, respectively. The results showed that all the co-crosslinked chitosan beads had the maximum adsorption ratio of trypsin inhibitor, lectin and phytic acid at pH 4.4, 5.4 and 2.2, respectively. The maximum adsorption ratios of trypsin inhibitors and lectin for were higher than that of CB7 and CB5. The maximum adsorption ratios of trypsin inhibitors and lectin for these beads adsorbing at 25℃were higher than that of 15℃ and 5℃. In pH 9.0 soltuion, the desorption ratios of phytic, trypsin inhibitors and lectin for adsorbed CB7 under pH 2.2, 4.4 and 5.4 were 43.6%, 73.14% and 65.81%, respectively. In short, the selective adsorption for trypsin inhibitor, lectin and phytic acid from soybean whey could be processed by chitosan/TPP/genipin co-crosslinked beads in appropriate conditions.
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CHIA, TU CHE, and 杜哲嘉. "Studies of adsorption of acid dyes (AO12、AO10、AR18) in aqueous solutions on chitosan gel bead crosslinked by glutaric dialdehyde." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/62081538094771526308.
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Shung-ErSua and 蔡尚爾. "Synthesis and Characterization of Crosslinked Poly(acrylic acid) Binder for Si Anode of Li-Ion Batteries with High Cycle Stability." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/hh7x2a.
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CHEN, YI, and 陳宜. "Characteristics of curing reaction and properties of crosslinked resins of the reactive blends of Meldrum’s acid derivatives and benzoxazine compounds." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/91870284849921249812.
Full textAbstract:
碩士國立清華大學
化學工程學系
104
This study focuses on Meldrum’s acid (MA) polymerization mechanism as well as the properties of the correspond crosslinked polymers. In the first part, MA derivatives are blended with benzoxazine compound (F-BZ) with tertiary amine structure, which is a Lewis base, to undergo thermolysis at a much lower temperature. By means of DSC, TGA, FT-IR and NMR characterization, we confirmed its catalytic effect and mechanism. Furthermore, by this reaction mechanism, different equivalent MA derivative (MA-F) are applied to modify polybenzoxazine. Results indicate polymers modified with MA-F have poor thermal stability due to the week bonding of ester group. In the second part, MA monomer with two furan group (MA-FBCB) was synthesized and used to polymerize with a bismaleimide compound through Diels-Alder reaction (DA reaction). The molecular structure was further verified by DSC, TGA, FT-IR. This polymer has better solubility and hence better potential than MA monomer (MA-FBCB). After crosslinking, a material with better thermal behavior and low dielectric constants was obtained.
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Hoffmann, Christian. "Structural investigation of the histone chaperone complex FACT using genetically encoded crosslinkers in Saccharomyces cerevisiae." Doctoral thesis, 2014. http://hdl.handle.net/11858/00-1735-0000-0023-9655-5.
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"Theoretical investigation of cisplatin-deoxyribonucleic acid crosslink products using hybrid molecular dynamics + quantum mechanics method." 2009. http://library.cuhk.edu.hk/record=b5893997.
Full textAbstract:
Yan, Changqing.Thesis (M.Phil.)--Chinese University of Hong Kong, 2009.
Includes bibliographical references (leaves 92-97).
Abstracts in English and Chinese.
ABSTRACT (ENGLISH) --- p.iii
ABSTRACT (CHINESE) --- p.iv
ACKNOWLEDGMENTS --- p.v
LIST OF ABBREVIATIONS --- p.vi
TABLE OF CONTENTS --- p.vii
LIST OF FIGURES --- p.ix
LIST OF TABLES --- p.x
Chapter CHAPTER ONE: --- BACKGROUND INFORMATION --- p.1
Chapter 1.1 --- Introduction --- p.1
Chapter 1.2 --- Deoxyribonucleic Acid --- p.2
Chapter 1.3 --- DNA Studies --- p.9
Chapter 1.4 --- Cisplatin Studies --- p.11
Chapter 1.5 --- Scope of the Thesis --- p.13
Chapter CHAPTER TWO: --- METHODOLOY AND COMPUTATION --- p.16
Chapter 2.1 --- Introduction --- p.16
Chapter 2.2 --- Molecular Dynamics Simulation --- p.16
Chapter 2.3 --- Quantum Mechanics Calculation --- p.23
Chapter 2.4 --- Verification of Methodology --- p.25
Chapter 2.4.1 --- Backbone Torsion Angles --- p.25
Chapter 2.4.2 --- N7-N7 Distance --- p.30
Chapter 2.4.3 --- Location of HOMO --- p.33
Chapter 2.5 --- Summary --- p.35
Chapter CHAPTER THREE: --- UNDERSTANDING OF THE CISPLATIN-DNA CROSSLINKS --- p.36
Chapter 3.1 --- Introduction --- p.36
Chapter 3.2 --- MO Analysis --- p.37
Chapter 3.3 --- Potential Binding Products with the Ligand --- p.37
Chapter 3.3.1 --- "1,2-d(GpG) Intrastrand Crosslink" --- p.43
Chapter 3.3.2 --- "l,2-d(ApG) Intrastrand Crosslink" --- p.43
Chapter 3.3.3 --- "l,3-d(GpXpG) Intrastrand Crosslink" --- p.44
Chapter 3.3.4 --- d(GpC)d(GpC) Interstrand Crosslink --- p.44
Chapter 3.3.5 --- d(GpXpC)d(GpXpC) Interstrand Crosslink --- p.44
Chapter 3.3.6 --- Summary --- p.45
Chapter 3.4 --- Potential Binding Products Analysis --- p.47
Chapter 3.4.1 --- Site Identification Convention --- p.47
Chapter 3.4.2 --- Potential Binding Products Analysis --- p.48
Chapter 3.4.3 --- Applications --- p.53
Chapter 3.5 --- Cisplatin-DNA Crosslink Products Analysis --- p.56
Chapter 3.5.1 --- "1,2-d(GpG) and l,2-d(ApG) Intrastrand Crosslinks" --- p.61
Chapter 3.5.2 --- "l,3-d(GpXpG) Intrastrand and d(GpXpC)d(GpXpC) Interstrand Crosslinks" --- p.62
Chapter 3.5.3 --- d(GpC)d(GpC) Interstrand Crosslinks --- p.63
Chapter 3.5.4 --- Platination at Terminal Positions --- p.65
Chapter 3.6 --- Summary --- p.65
Chapter CAHPTER FOUR: --- CONCLUDING REMARKS --- p.67
APPENDIX I: BACKBONE TORSION ANGLES AND SUGAR RING CONFORMATIONS OF THE OPTIMIZED GEOMETRIES --- p.69
APPENDIX II: BACKBONE TORSION ANGLES OF THE EXPERIMENTAL SEQUENCES FROM NUCLEIC ACID DATABASE (NDB) --- p.77
REFERENCES --- p.92
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CHEN, Jui-Chin, and 陳瑞金. "The study of Metallic Salts After-Treatment and Plasma Treatment on the Multi-functional Crosslinked Cotton Fabrics with Combined Dimethyloldihydroxyethyleneurea and Acrylic Acid." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/28169632078771427433.
Full textAbstract:
博士國立臺灣科技大學
高分子工程系
94
In this study, we used three metallic salts to after-treat the DMDHEU-AA crosslinked cotton fabrics, and find that the DCRA, WCRA, TSR and MR values of the crosslinked and after-treated fabrics are in the order of Ag＋ > Cu＋2 > Al＋3 at a same DMDHEU-AA concentration in padding bath. The DCRA and WCRA of the crosslinked and after-treated fabrics are higher than those of the DMDHEU-AA crosslinked fabrics, and those for crosslinked and after-treated fabrics are in the order of Ag＋ > Cu＋2 > Al＋3 at a given values of TSR. For a given CL/AGU, DCRA and TSR values for the crosslinked and after-treated fabrics are higher than those for the DMDHEU-AA crosslinked fabrics, and those for crosslinked and after-treated fabrics are in the order of Ag＋ > Cu＋2 > Al＋3; but WCRA values of the various treated fabrics show that the values for the crosslinked and after-treated fabrics are lower than those for the DMDHEU-AA crosslinked fabrics, and those for crosslinked and after-treated fabrics are in the order of Ag＋ > Cu＋2 > Al＋3. IR spectra clearly show the interaction between the －OH group of the cellulose and the metallic ions, which are different from each other on the bonding state for the various metallic ions, and the strength of the bonding for the various metallic ions are in the order of Ag＋ > Cu＋2 > Al＋3. All crosslinked and after-treated fabric samples have good values of odor absorption, anti-bacteria, and washing fastness. In addition, the low temperature plasma treatment was applied for finishing the cotton fabrics, and the effect of plasma treatment on the durable press finishing of cotton fabric was studied. Both DMDHEU alone and DMDHEU-AA crosslinking agents were used to finish cotton fabrics with various processes by changing agent concentrations in the bath. Experimental data indicate that the plasma treatment within the pad-dry-plasma-cure process can induce the cotton fabrics surface binding of more crosslinking agents than the samples without plasma treatment. For the same crosslinking agents, we find that the DCRA, WCRA and TSR values of the pad-dry-plasma-cure fabrics are higher than the pad-dry-cure fabrics at a given value of nitrogen content. In addition, the values of TSR for the pad-dry-plasma-cure process are also higher than those for the pad-dry-cure process at a given DCRA or WCRA. For all the four treated processes, the N content, DCRA and WCRA values of the DMDHEU-AA-treated fabrics are all higher than those of the DMDHEU-treated fabrics at a same resin concentration in the bath, but the TSR values are inverse in all cases. For the same crosslinking agents, we also find that the numbers of CL/AGU and CL length of pad-dry-plasma-cure fabrics are higher than the pad-dry-cure fabrics at a same DMDHEU concentration in the bath. And at a same CL/AGU value, the DCRA, WCRA and TSR values of the pad-dry-plasma-cure fabrics are higher than those for the pad-dry-cure fabrics. Those results show that the plasma treatment can not only introduce the crosslinking reaction between the resins and cellulose molecules, but also can clearly improve physical properties such as tensile strength and wrinkle recovery angle. In this study, we also used the combined DMDHEU and acrylic acid crosslinking agent to treat cotton fabric under a pad-dry-plasma-cure process to study the pore property, anti-bacterial property, and agent distribution. For both direct dyes used, we find that the values of dye absorptions, equilibrium absorption and the rate constants, structural diffusion resistance constants for the pad-dry-plasma-cure treated fabrics are lower than those for pad-dry-cure treated fabrics at the initial dyeing time duration, but the activation energies for the two finished fabrics (dyed with the same direct dye) are ranked pad-dry-plasma-cure＞ pad-dry-cure. The carboxylic acid group of acrylic acid could react with copper sulfate to bind the copper ion on the treated fabric surface, which could improve the anti-bacterial ability significantly. The surface distribution of crosslinking agent on the finished fabrics is somewhat higher for pad-dry-plasma-cure process than for pad-dry-cure process.
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Wick, Kyle Lynn. "Interactions between lac repressor protein and bromodeoxyuridine-substituted operator DNA: Identification of a specific amino acid-nucleotide contact using UV footprinting and crosslink formation." Thesis, 1990. http://hdl.handle.net/1911/16407.
Full textAbstract:
As the classical model for negative transcriptional control in prokaryotes and the subject of concentrated experimental attention, the lactose operon of Escherichia coli presents a well-defined system for studying genetic control through protein-DNA binding interactions. Binding of repressor at its cognate operator sequence within the regulatory region of the operon, while responsive to environmental conditions, efficiently inhibits transcription initiation by RNA polymerase. The high binding affinity and degree of specificity exhibited by this protein-DNA complex has encouraged investigation of the nature of the contacts formed.
We have explored specific contacts between the lac repressor and operator using 5-bromodeoxyuridine-substituted DNA. Substitution of BrdU for single thymidine positions in a synthetic 40 bp operator provides an indirect means of probing the major groove of operator DNA for critical contacts between the repressors and the 5-methyl of individual thymidines. As a photoreactive species, BrdU provides substrate for ultraviolet irradiation. Upon irradiation, strand scission occurs at the BrdU residues. When bound, lac repressor protein provides protection against UV-induced breakage depending on the nature of the sites and type of interaction. We have confirmed thirteen unique sites of inducer-sensitive protection along the operator sequence (+1, 2, 3, 4, 6, 8, 13, 15, 16, 18, 19, 20, 21) using this method compared to per-substitution with BrdU (Ogata and Gilbert, 1977). The ability of these photosensitive DNAs to form short-range cross-links to bound protein has been used to determine the efficiency with which cross-linked protein-DNA complexes are generated at each individual site of BrdU substitution. Five sites of high efficiency cross-linking to the repressor protein have been identified (+3, 4, 14, 18, 19). Comparison of the UV protection results and the cross-linking data shows that these processes provide complementary tools for identifying and analyzing individual protein-DNA contacts.
Using these same BrdU-substituted operator DNAs, we attempted to define individual protein-DNA interactions with respect to the specific amino acid(s) making contact at a selected site within the operator sequence. With the selection of the T$\sb{+3}$ site for our initial investigation, the cross-linked complex was formed and isolated. These polypeptide-DNA species were prepared for final analysis through a series of steps including proteolysis and anion-exchange HPLC. Protein sequence analysis on the purified peptide-operator complex identified a peptide spanning Val23 through Lys33. The data suggest His29 as the specifically crosslinked amino acid.