Dissertations / Theses: 'Reactive molecules'

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Tong, Yongfeng. "Self-Assembly of Organic Molecules on Reactive Metal Substrates." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS522/document.

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Dans cette thèse, la formation de monocouches auto-assemblées de différentes molécules de chalcogénure et de molécules p-conjuguées planaire et leurs caractéristiques structurelles et électroniques ont été systématiquement étudiées principalement par spectroscopie photoélectronique à rayons X effectuée utilisant la lumière synchrotron, microscopie à effet tunnel à balayage et diffraction d'électrons à faible énergie. Une étude de la formation de structures hybrides organiques-inorganiques auto-assemblées a été réalisée par assemblage couche par couche d'un dithiol sur ZnO (0001) avec dépôt de métal intermédiaire. De plus en complément de l'étude des molécules comportant un atome de chalcogènure, les caractéristiques d'adsorption du sélénium et du soufre ont été étudiées. La spectroscopie XPS à haute résolution et la spectroscopie de structure fine d’absorption au seuil d’excitation (NEXAFS) ont permis d'étudier les caractéristiques des monocouches auto-assemblées du sélénure de benzène et du sélénophène sur Cu (100) et dihexyldiselénure sur Ni (111) et Pd (111) et ont montré en particulier l’existence de processus de rupture de liaison Se-C ainsi que l’existence de différents sites d'adsorption de molécules. Ces conclusions ont été soutenues par l'étude de l'adsorption atomique du sélénium, qui montre également l'existence de différents sites d'adsorption pour le Se atomique avec différents environnements chimiques. Ces conclusions sont principalement basées sur une étude XPS haute résolution des spectres caractéristiques Se3d, Se3p, du spectre de bande de valence et de l'imagerie LEED. La formation de monocouche de 5,5-bis (mercaptéthyl) -2,20-bipyridine (BPD) avec terminaison SH libre sur ZnO(0001) a été démontrée, permettant le greffage ultérieur d'Ag et Ni et de l’ assemblage d’une autre couche de BPD sur cette couche de métal-dithiol. Les changements dans les propriétés électroniques ont été déterminés à partir des spectres de la bande de valence. La molécule π-conjuguée, NTCDA, a été déposée sur différentes surfaces métalliques et sa morphologie structurelle et ses propriétés chimiques par rapport à la surface métallique ont été étudiées. Les molécules NTCDA affichent une structure « couchée » avec deux domaines différents sur Ag (110) et Cu (100) mais trois domaines sur la surface de Cu (111). Par rapport à celui sur la surface inerte de Au, une forte interaction entre les molécules et les substrats de Cu, Ag existe et joue un rôle important dans la détermination de l'orientation et de l'état de liaison des films organiques
In this thesis, the formation of self-assembled monolayers of different chalcogenide molecules and planer π-conjugated molecules and their electronic and structural characteristics were systematically studied mainly by synchrotron based X-ray photoelectron spectroscopy, scanning tunneling microscopy and low energy electron diffraction. A study of formation of hybrid organic-inorganic self assembled structure was performed by layer by layer assembly of a dithiol on ZnO(0001) with intermediate metal deposition. Additionally as a complement to the study of chalcogen head group molecules the adsorption characteristics of selenium and sulfur were investigated. The high resolution XPS and near edge absorption fine structure spectroscopy allowed to investigate the characteristics of self-assembled monolayers of benzene selenide and selenophene on Cu (100), and dihexyldiselenide on Ni(111) and Pd(111) and showed in particular the existence of Se-C bond breaking processes and existence of different adsorption sites of molecules. These conclusions were supported by the study of atomic selenium adsorption, which also shows existence different adsorption sites for the atomic Se with different chemical environments. These conclusions are mainly based on high resolution XPS study of characteristic Se3d, Se3p spectra, valance band spectrum and LEED imaging. The formation of a 5,5- bis (mercaptomethyl)-2,20- bipyridine (BPD) with SH termination on ZnO(0001) was demonstrated allowing subsequent grafting of Ag and Ni and further assembly of BPD on this metal-dithiol layer. The changes in electronic properties were determined from valence band spectra. The large π-conjugated molecule, NTCDA, was deposited on different metal surfaces and its structure morphology and chemical properties with respect to the metal surface was investigated. The NTCDA molecules displays a lying down structure with two different domains on Ag (110) and Cu(100) but three domain on Cu(111) surface. Compared with the one on the inert Au surface, a strong interface interaction between the molecules and Cu, Ag substrates plays an important role in determining the orientation and bonding state of the organic films

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Marinov, Daniil. "Reactive adsorption of molecules and radicals on surfaces under plasma exposure." Palaiseau, Ecole polytechnique, 2012. https://pastel.hal.science/docs/00/75/29/87/PDF/PhD_DM.PDF.

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Les sources d'atomes, la protection thermique pour la rentrée atmosphérique et la dépollution de l'air par couplage plasma-catalyseur voici quelques exemples d'applications pour lesquelles l'interaction plasma-surface joue un rôle principal. Les mécanismes des réactions hétérogènes dans les plasmas contenant les gaz atmosphériques N2/O2 sont encore peu compris. La précision et la capacité de prédiction des modèles cinétiques sont limitées par la connaissance des conditions de la surface. Dans la première partie de ce travail, nous avons étudié l'adsorption et les réactions chimiques des atomes O et N sur des surfaces de différents oxydes (silice, Pyrex, TiO2) sous exposition plasma. Nous avons utilisé la spectroscopie d'absorption par laser accordable, la spectroscopie d'absorption UV, la fluorescence induite par laser à deux photons (TALIF) et la spectrométrie de masse pour suivre l'interaction entre les espèces en phase gaz et les surfaces. L'analyse chimique de surface a été effectuée par spectrométrie photoélectronique X (XPS). Nous avons montré que des atomes stables Nads et Oads peuvent être chimisorbés sur la surface par plasma dans O2 et N2 à basse pression (~ 1 mbar). Leur densité et la réactivité ont été évaluées par réactions avec des molécules stables (NO, C2H2) et des radicaux (O, N) sur la surface prétraitée. Le rôle des atomes chimisorbés pour la recombinaison hétérogène d'atomes a été étudié en utilisant l'échange isotopique 15N ↔ 14Nads et 18O ↔ 16Oads sous exposition plasma. Dans la deuxième partie de cette thèse, nous avons étudié la relaxation vibrationnelle des molécules de N2 sur des surfaces catalytiques par la technique de titrage infrarouge (IR). Des mélanges contenant 0,05 - 1% de CO2 (CO ou N2O) dans N2 à la pression p = 1,3 mbar ont été excités par une décharge dc pulsée. La cinétique de la relaxation vibrationnelle des traceurs IR dans la post-décharge a été mesurée par un laser à cascade quantique. Grace à un couplage très efficace entre N2 et CO2 (CO ou N2O), l'excitation vibrationnelle de CO2 (CO ou N2O) reflet l'excitation de N2. Un modèle numérique de la cinétique vibrationnelle a été développé afin d'interpréter les mesures de relaxation. La probabilité de perte d'un quanta vibrationnel de N2 sur la surface a été déterminée à partir du meilleur accord entre l'expérience et le modèle
Atomic sources, thermal protection for atmospheric re-entry and plasma-catalyst systems for air pollution control are just few examples of applications where interaction between N2/O2 containing plasmas and the surface plays a central role. Mechanisms of heterogeneous processes in plasmas are still barely understood. Unknown conditions on the surface limit the accuracy and predictive capability of the kinetic models. In the first part of this work we investigate adsorption and chemical reactions of O and N atoms on oxide surfaces (silica, Pyrex, TiO2) under plasma exposure. We use tuneable laser absorption spectroscopy, broad-band UV absorption spectroscopy, two-photon absorption laser-induced fluorescence (TALIF) and mass spectrometry to monitor interaction between gas phase species and the surface. Surface analysis is performed using x-ray photoelectron spectroscopy (XPS). It has been shown that stable Oads and Nads atoms are grafted to oxide surfaces under exposure to low pressure (~1 mbar) plasmas in O2 and N2. The coverage and reactivity of adsorbed atoms has been probed by exposing the pretreated surface to stable molecules (NO, C2H2) and radicals (O, N). Using isotopic exchange 15N↔14Nads and 18O↔16Oads under plasma exposure the role of chemisorbed species in surface catalysed recombination of atoms has been investigated. In the second part of this thesis, relaxation of vibrationally excited N2 molecules on catalytic surfaces is studied using infrared (IR) titration technique. Mixtures containing 0. 05 - 1% of CO2 (CO, N2O) in N2 at p=1. 3 mbar are excited by a single dc discharge pulse. The kinetics of vibrational relaxation of IR tracers during the post-discharge is followed using quantum cascade laser absorption spectroscopy. Due to a very efficient vibrational energy transfer between N2 and CO2 (CO, N2O), excitation of IR tracers is an image of the vibrational excitation of N2. Relaxation measurements have been interpreted in terms of a numerical model of non-equilibrium vibrational kinetics. Probability of N2 vibrational quantum loss has been determined from the best agreement between the experiment and the model

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Park, Sung H. "High Affinity Block of ICl,swell by Thiol-Reactive Small Molecules." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4433.

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Ebselen (Ebs) is considered as a glutathione peroxidase (GPx) mimetic and primarily thought to function by scavenging intracellular reactive oxygen species (ROS). Previous to our work, Deng et al. (2010a) demonstrated complete block of ICl,swell with 15 microM Ebs following endothelin-1 (ET-1) induced activation of the current in cardiomyocytes. This block was presumed to take effect mainly via the quenching of ROS. Nonetheless, our work with DI TNC1 astrocytes strongly emphasizes that Ebs might function by an alternative mechanism based on its kinetic profile in blocking ICl,swell. Our experiments showed that 45 nM Ebs can fully block ICl,swell thus suggesting an apparent IC50 result, we predicted Ebs to possess a high kon with a low koff close to zero. As predicted, Ebs failed to washout in the timescale covered by our patch-clamp experiments. The block was also distal to H2O2, previously considered as the most proximate regulator of ICl,swell. And based on further evidence demonstrating irreversible block of ICl,swell distal to H2O2 with Ebs congeners, complete suppression of native ICl,swell with MTS reagents, and failure of Ebs to block ICl,swell from the cytosol, we concluded that Ebs and its congeners can covalently modify important –SH groups required for current activation while functioning as sulfhydryl reagents. Complete irreversible block of ICl,swell with 110 mM cell impermeant MTSES in native DI TNC1 astrocytes contrasts sharply to SWELL1 (Qiu et al., 2014) or LRRC8A (Voss et al., 2014), the latest molecular entity presumably responsible for ICl,swell, where 3.33 mM MTSES failed to demonstrate block of ICl,swell in the wild-type stably expressing SWELL1 (Qiu et al., 2014). Our data with Ebs, its congeners, and MTS reagents indicate the existence of a common extracellular binding site which involves a selenenylsulfide (Se-S) bond that critically modulates ICl,swell. We, therefore, synthesized a derivative of Ebs called ebselen-para-yne (Ebs-p-yne), which provided an even higher affinity for blocking ICl,swell with a presumed IC50 ~picomolar range. Ebs-p-yne is a promising novel molecule that may serve as a tag in identifying the molecular fingerprint ultimately responsible for ICl,swell. Furthermore, we can take advantage of click chemistry to ultimately pull out the channel or channel component which has remained elusive for greater than two decades.

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Hobbs, Christopher Leslie. "Ab initio studies into the nanoscale manipulation of molecules on reactive surfaces." Thesis, King's College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439882.

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Schröder, Benjamin. "Theoretical high-resolution spectroscopy for reactive molecules in astrochemistry and combustion processes." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0005-12DA-1.

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Phillips, Darren C. "Ceramide and reactive oxygen species (ROS) as signal transduction molecules in inflammation." Thesis, Aston University, 2003. http://publications.aston.ac.uk/12363/.

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The application of synthetic ceramides to U937 monocytes for short (2 hours) or long (16 hours) treatment periods reduced the membrane expression of proteins associated with cell-cell interaction. Furthermore, ceramide treated U937 monocytes demonstrated reduced adhesion to 5 or 24 hour LPS activated human umbilical vein endothelial cells (HUVEC) but not resting HUVEC. Consequently it is hypothesised that the targeted treatment of monocytes from patients with cardiovascular diseases with short chain synthetic ceramide may reduce disease progression. Herein, the anti-inflammatory and immunosuppressant drug, methotrexate, is described to require ROS production for the induction of cytostasis or cytotoxicity in U937 monocytes and Jurkat T-cells respectively. Further, ROS are critical for methotrexate to abrogate monocyte interaction with activated HUVEC in vitro. The histological feature of RA of enhanced infiltration, survivability and hyporesponsiveness of T-cells within the diseased synovium has been suggested to arise from aberrant signalling. No difference in the concentrations of endogenous T-cell ceramide, the related lipid diacylglycerol (DAG) and cytosolic peroxide ex vivo was observed. TCR activation following PHA exposure in vitro for 72 hours did not induced maintained perturbations in DAG or ceramide in T-cells from RA patients or healthy individuals. However, T-cells from RA patients failed to upregulate cytosolic peroxide in response to PHA, unlike those from normals, despite expressing identical levels of the activation marker CD25. This inability to upregulate cytosolic peroxide may contribute to the T-cell pathology associated with RA by affecting the signalling capacity of redox sensitive biomolecules. These data highlight the importance of two distinctive cellular pools of ROS in mediating complex biological events associated with inflammatory disease and suggest that modulation of cellular ceramides represents a novel therapeutic strategy to minimise monocyte recruitment.

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Clothier, Stacy Lauren. "Immune Checkpoint Molecule Expression in Canine Lymphoma and Canine Reactive Lymphoid Hyperplasia." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/103200.

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Background: Although lymphoma is one of the most common malignancies in dogs, remission rates and survival times remain stagnant. Treatment with a multi-agent chemotherapy protocol induces remission for less than one year and the majority of patients relapse. Fewer than 25% of dogs live longer than two years with the currently available treatments. Targeted immunotherapy using checkpoint molecule blockade of PD-1 and PD-L1 shows promise for various types of human cancer, including relapsed/refractory lymphoma; however, little is known regarding the role of these checkpoint molecules in canine lymphoma. Objectives: To determine the patterns of expression of mRNAs encoding PD-1 and its ligands PD-L1 and PD-L2 in lymphoma and reactive lymphoid hyperplasia controls. Methods: Retrospective: formalin-fixed paraffin-embedded (FFPE) tissue from dogs with untreated lymphoma (n=10) and reactive lymphoid hyperplasia (n=10). Prospective: fine-needle aspirates (FNAs) from dogs with untreated lymphoma (n=10) and reactive lymphoid hyperplasia (n=10). Total RNA was extracted, and expression of PD-1, PD-L1, and PD-L2 was measured using qRT-PCR analysis of random-primed cDNA. Checkpoint molecule expression levels were determined using the 2^∆∆CT method. Lymphoma immunophenotype was assessed using immunohistochemical analysis of CD3 and CD79a (FFPE) and review of patient medical records (FNA). Data analysis included Wilcoxon ranksum tests, Dunn's procedure of multiple comparisons, Kruskal-Wallis tests, and regression within an ANOVA. Significance at P < 0.05. Results: PD-1, PD-L1, and PD-L2 expression (normalized internally to 18S rRNA) was lower in lymphoma compared to reactive lymphoid hyperplasia (FFPE); the difference was significant for PD-1 and PD-L2. PD-1 and PD-L2 expression was lower in lymphoma compared to reactive lymphoid hyperplasia (FNA); the difference was significant for PD-1. PD-1, PD-L1, and PD-L2 expression was lower in B cell lymphoma compared to reactive lymphoid hyperplasia (FFPE); this difference was significant for PD-1 and PD-L2. PD-1 and PD-L2 expression was lower in B cell lymphoma compared to reactive lymphoid hyperplasia (FNA); the difference was significant for PD-1. The higher relative abundance of PD-L1 vs PD-1 and PD-L2 vs PD-1 was significantly different between lymphoma and reactive lymphoid hyperplasia (FFPE and FNA). Conclusions: In this study, checkpoint molecule expression was not upregulated in canine lymphoma relative to canine reactive lymphoid hyperplasia, suggesting a limited application of PD-1 and PD-L1 blockade in canine lymphoma. The ligand:receptor relative abundance imbalances reflect the lower PD-1 expression relative to PD-L1 and PD-L2 in lymphoma. Although these results do not suggest that checkpoint inhibitors would be useful for treatment, they give insight into the mechanisms of unchecked lymphocyte proliferation in canine lymphoma.
Master of Science
General Abstract Lymphoma, a cancer of the white blood cells in the body, is one of the most common malignancies in dogs. Although treatment with a multi-agent chemotherapy protocol results in high remission rates, the remission duration is usually less than one year, with the majority of patients relapsing. In an effort to improve remission rates and survival times, scientists have been working to develop therapeutic interventions that target specific points in the development and replication cycle of a cancer cell. One such strategy, targeting checkpoint molecules programed death (PD)-1 and PD-L1, has shown promise for several different types of human cancers, including lymphoma. PD-1 is a receptor on T cells, which together with its ligands, PD-L1 and PD-L2, decreases lymphocyte function when activated. This is a protective mechanism, acting to inhibit sustained harmful inflammation in a normal healthy dog. Some cancers have taken advantage of this pathway, increasing expression of PD-L1 or L-L2 in order to evade detection by the immune system. To date, little is known regarding the role and expression of these immune checkpoint molecules in dogs with lymphoma. We sought to evaluate if PD-1, PD-L1 and PD-L2 expression is significantly increased in canine lymphoma compared to reactive lymphoid hyperplasia controls. Tissue samples were collected from two sources. Cytology samples of lymphoma and reactive lymphoid hyperplasia were collected by fine needle aspiration from clinical patients. Formalin fixed paraffin embedded tissue samples of lymphoma and reactive lymphoid hyperplasia were collected from the archived tissue bank. Using a molecular analysis technique called quantitative reverse transcription PCR (qRT-PCR) we measured the amount of messenger RNA (mRNA) encoding PD-1 and its ligands PD-L1 and PD-L2 in lymphoma and in reactive lymphoid hyperplasia controls. In our results we did not observe an upregulation in the expression of checkpoint molecules in canine lymphoma relative to canine reactive lymphoid hyperplasia. This suggests there may be a limited therapeutic application for PD-1 and PD-L1/PD-L2 blockade in canine lymphoma. Although these results do not suggest that checkpoint inhibitors would be useful for treatment, they give insight into the mechanisms of unchecked lymphocyte proliferation in canine lymphoma.

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Holzmeier, Fabian [Verfasser], and Ingo [Gutachter] Fischer. "Photoionization of Nitrogen-Containing Reactive Molecules with Synchrotron Radiation / Fabian Holzmeier. Gutachter: Ingo Fischer." Würzburg : Universität Würzburg, 2016. http://d-nb.info/1112040951/34.

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Schröder, Benjamin [Verfasser]. "Theoretical high-resolution spectroscopy for reactive molecules in astrochemistry and combustion processes / Benjamin Schröder." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://d-nb.info/1216330557/34.

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Premnauth, Gurdat. "Design, Synthesis and Biological Evaluation of New Molecules to Selectively Target Specific Cancers." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613744938434214.

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Graham, Robin Michelle. "Activation of systemic adhesion molecules and C-reactive protein in response to biomaterial particle induced cytokine production." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1202409163/.

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Pham, Duc Thanh [Verfasser]. "Self-assembly of viologen molecules at metal/electrolyte interfaces under non-reactive and reacrtive conditions / Duc Thanh PHAM." Bonn : Universitäts- und Landesbibliothek Bonn, 2011. http://d-nb.info/1044083018/34.

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Zugermeier, Malte Sikko Albrecht [Verfasser], and J. Michael [Akademischer Betreuer] Gottfried. "Reactive Aromatic Molecules on Metal Surfaces: Syntheses, Reactions and Structures / Malte Sikko Albrecht Zugermeier ; Betreuer: J. Michael Gottfried." Marburg : Philipps-Universität Marburg, 2018. http://d-nb.info/1166314103/34.

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Wilke, Julian [Verfasser], Herbert [Akademischer Betreuer] Waldmann, and Markus [Gutachter] Kaiser. "Identification and characterization of small molecules inducing cellular reactive oxygen species accumulation / Julian Wilke ; Gutachter: Markus Kaiser ; Betreuer: Herbert Waldmann." Dortmund : Universitätsbibliothek Dortmund, 2020. http://d-nb.info/1225937809/34.

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Girard, Bertrand. "Etude de la collision reactive ii + f -> if + i par fluorescence induite par laser." Paris 6, 1987. http://www.theses.fr/1987PA066398.

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Etude de cette collision par la methode des faisceaux croises et grace a la transition (b <- x) intense, dans le visible, apres analyse de la saturation du processus d'excitation laser de cette transition de if forme. Deduction des populations des differents niveaux rovibrationnels de l'etat x. Etablissement d'une cartographie detaillee de la distribution rotationnelle des niveaux vibrationnels v = 8 a 20 de l'etat x de if: aspect bimodal qui implique la coexistence de deux chemins reactionnels differents. Attribution a un artefact de l'important signal observe anterieurement pour v = 0. Mesures preliminaires de la section efficace differentielle par effet doppler

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Gadea, Florent Xavier. "Theorie des hamiltoniens effectifs : applications aux problemes de diabatisation et de collision reactive." Toulouse 3, 1987. http://www.theses.fr/1987TOU30276.

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Etude approfondie sur la theorie des hamiltoniens effectifs et analyse de leurs applications aux methodes de diabatisation et au traitement des collisions reactives. Propositions pour le calcul des valeurs propres de l'hamiltonien par des methodes de perturbation ou iteratives, pour l'emploi d'hamiltoniens effectifs dans le calcul des surfaces quasi diabatiques et le traitement general des collisions reactives. Application a la reaction cs+h::(2) etudiee par les methodes ab initio pour la geometrie colineaire : surfaces de potentiel, sections efficaces et mecanismes predominants

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Tikhomirova, Anastasiia. "Studies of Photoinduced DNA Damage by Phenanthrene Dihydrodioxin and Light-driven Electron Delocalization in Pyridinium Molecules." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1561918589357022.

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Chandra, Anirban. "Synthesis of Bioinspired Dioxygen Reduction Catalysts Involving Mono and Polynuclear Late Transition Metal Complexes and Spectroscopic Trapping of Reactive Intermediates." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22579.

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Die selektive Funktionalisierung nicht aktivierter C−H-Bindungen und die Disauerstoffreduktionsreaktion (ORR) sind extrem wichtig bei der Beschäftigung mit verschiedenen technologischen Problemstellungen wie der Energiekrise, der Synthese kommerziell relevanter organischer Verbindungen usw. Die Nutzung molekularen Sauerstoffs als reichlich vorhandenes und umweltverträgliches Oxidationsmittel ist von großem Interesse in der Entwicklung bioinspirierter synthetischer Oxidationskatalysatoren. Die katalytische Vier-Elektronen-Reduktion von Disauerstoff zu Wasser erlangte auch immer größere Aufmerksamkeit wegen ihrer Bedeutung in der Brennstoffzellentechnologie. Natürlich vorkommende Metalloenzyme aktivieren Disauerstoff durch die Nutzung günstiger Übergangsmetalle (z.B. Eisen, Nickel, Mangan und Kupfer) und weisen diverse oxidative Reaktivitäten auf. Des Weiteren werden solche Reaktionen unter Umgebungsbedingungen mit hoher Effizienz und Stereoselektivität durchgeführt. Deshalb kann die Isolierung und Charakterisierung hochvalenter Metall-Disauerstoff-Intermediate (wie Metall-Superoxo-, Metall-Peroxo-, Metall-Hydroperoxo- und Metall-Oxo-Verbindungen) eine Menge nützlicher Informationen über die Reaktionsmechanismen liefern und daher hilfreich für die zukünftige Entwicklung effizienterer Katalysatoren sein. Diese Arbeit hat die Chemie verschiedener Metall-Disauerstoff-Intermediate von end-on-1,2-Peroxo-dicobalt(III)-Spezies bis zu Superoxo-nickel(II)-Kernen erforscht. Detaillierte spektroskopische Untersuchungen sowie Reaktivitätsstudien der Intermediate wurden durchgeführt, um den Zusammenhang zwischen ihrer elektronischen Struktur und ihren Reaktivitätsmustern aufzuklären. In meiner Arbeit untersuchte ich den Effekt der ‚Struktur-Aktivität-Beziehung‘ verschiedener Metall-Disauerstoff-Intermediate gegenüber exogener Substrate. Diese Arbeit zeigte auch den Einfluss des Designs geeigneter Liganden auf das Verhalten eines gegebenen reaktiven Metall-Disauerstoff-Systems.
Selective functionalization of unactivated C−H bonds and dioxygen reduction reaction (ORR) are extremely important in the context of addressing various technological issues such as energy-crisis, synthesis of commercially important organic compounds, etc. The utilization of molecular oxygen as an abundant and environmentally benign oxidant is of great interest in the design of bioinspired synthetic oxidation catalysts. The catalytic four-electron reduction of dioxygen to water has also merited increasing attention because of its relevance to fuel cell technology. Naturally occurring metalloenzymes activate dioxygen by employing cheap transition metals (e.g. iron, nickel, manganese, and copper) and exhibit diverse oxidative reactivities. Moreover, such reactions are carried out under ambient conditions with high efficiency and stereospecificity. Therefore, the isolation and characterization of the high-valent metal-dioxygen intermediates (such as metal-superoxo, -peroxo, -hydroperoxo, and -oxo can provide a lot of useful information about the reaction mechanisms and is therefore helpful for the future design of more efficient catalysts. This thesis has explored the chemistry of different metal-dioxygen intermediates ranging from bridging end-on μ-1,2-peroxo-dicobalt(III) species to nickel(II)-superoxo cores. Detailed spectroscopic and reactivity studies of the intermediates have been performed to reveal the correlations between their electronic structures and reactivity patterns. In my present thesis, I investigated the effect of the ‘structure-activity relationship’ of different metal-dioxygen intermediates towards exogenous substrates. This thesis also demonstrated the impact of suitable ligand design on the behaviour of a given metal-dioxygen reactive system.

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Quichaud, Viviane. "Etude des processus elementaires : de synthese de la molecule no, en post-decharge en ecoulement, de collisions titane-gaz rares, titane-molecules, par perturbation laser resolue en temps." Paris 6, 1987. http://www.theses.fr/1987PA066135.

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I. Etude de la preparation des etats excites de no dans un dispositif de post-decharge en ecoulement a partir de n::(2) excite (prepare par transfert d'excitation a partir d'atomes ar metastables dans une decharge basse pression) et de o (obtenu par dissociation de o::(2) dans une decharge de he). Observation d'une emission intense des bandes gamma de no, qui implique un etat a courte duree de vie (b) de n::(2) et le premier etat metastable de o. Ii. Analyse des processus d'extinction et de transfert d'excitation a partir d'etats a courte duree de vie de ti (crees dans un dispositif a cathode creuse) lors de collisions avec des gaz rares (ar, ne, he) et des molecules (n::(2),h::(2)). Ces experiences permettent l'etude de cinetiques de reactions elementaires au sein d'un plasma basse pression ensemence de vapeurs metalliques, a l'aide du dispositif de post-decharge en ecoulement

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Kujbida, Paula da Silva. "Efeitos das microcistinas sobre funções de neutrófilos." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-05062017-151650/.

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Microcistinas (MCs) são heptapeptídeos cíclicos produzidos por cianobactérias e possuem potente hepatotoxicidade e atividade promotora de tumor. Em intoxicações agudas induzidas por MCs ocorre infiltração leucocitária no foco inflamatório. Embora os mecanismos de hepatotoxicidade não são claros, o recrutamento de neutrófilos no fígado pode contribuir ao dano tecidual e desenvolvimento tumoral causados por xenobióticos. O objetivo dessa tese foi investigar os efeitos de três estruturalmente distintas MCs (MC-LA, MC-YR e MC-LR) nas seguintes funções de neutrófilos: síntese e expressão de moléculas de adesão, rolamento, adesão, migração e liberação de citocinas e de ROS. Nos ensaios de migração em bolsa de ar, as três MCs induziram similarmente a migração de leucócitos in vivo em tecido subcutâneo de ratos e diferencialmente a secreção de citocinas pró-inflamatórias (CINC, IL-1β, TNF-α, VEGF-α e MIP) no exsudato. Concentrações elevadas de CINC-2αβ foram encontradas nos exsudatos inflamatórios de animais após injeção de MC-LA, MC-LR ou MC-YR. MIP-2 elevou-se apenas em exsudatos de animais expostos a MC-LR. Não foram observadas alterações em secreção de IL-1β, TNF-α e VEGF-α. Estudos de microscopia intravital mostraram que apenas a aplicação tópica de MC-LR reforçou o rolamento e a adesão de leucócitos no endotélio de vênulas mesentéricas pós-capilares. Esses últimos resultados podem ser dependentes de aumento e expressão da síntese da L-selectina e β2-integrina nos neutrófilos, tal como avaliado por FACS e PCR-RT, respectivamente. Adicionalmente, em ensaios em câmara de Boyden in vitro, as três MCs promoveram locomoção direta de neutrófilos e aumentaram a migração dessas células em resposta ao fMLP, além do aumento de cálcio intracelular observado por microscopia confocal. Os efeitos das MC-LA, MC-YR e MC-LR em neutrófilos humanos e de ratos tiveram o mesmo padrão de resposta. A análise de viabilidade celular, fragmentação de DNA, despolarização de membrana mitocondrial e liberação de ROS intracelulares foram avaliadas pela técnica de FACS. A concentração de ROS extracelular foi medida por quimiluminescência amplificada por lucigenina. A produção de citocinas em células tratadas foram determinadas por ELISA. Observamos aumento da liberação de IL-8, CINC-2α β e da concentração de ROS extracelular por neutrófilos humanos e de ratos pela exposição dessas células com as MCs. Os resultados aqui obtidos mostram o efeito pró-inflamatório direto das MC-LA, MC-YR e MC-LR. A possibilidade de os neutrófilos migrarem e responderem localmente a MCs contribui para a toxicidade destas toxinas.
Microcystins (MCs) are a family of heptapeptide toxins produced by some genera of Cyanobacteria. MCs have potent hepatotoxicity and tumor-promoting activity. Leukocyte infiltration in the liver was observed in MC-induced acute intoxication. Although the mechanisms of hepatotoxicity induced by MCs are still unclear, neutrophil infiltration in the liver may play an important role in triggering toxic injury and tumor development. The purpose of this thesis was to investigate the effects of three structurally distinct MCs (MC-LA, MC-YR and MC-LR) in the neutrophil functions: synthesis and expression of adhesion molecules, rolling, adhesion, migration and release of cytokines and ROS. In migration assays of the air pouch, the three MCs similarly induced the migration of leukocytes in vivo in subcutaneous tissue of rats and differentially the secretion of pro-inflammatory cytokines (CINC-2αβ, IL-1-β, TNF--α, VEGF- α and MIP-2) in exudates. Elevated concentrations of CINC-2αβ were found in the inflamed exudates from animals injected with MC-LA, MC-LR or MC-YR, although MIP-2 was only detected in the exudates from animals injected with MC-LR. There were no changes in the secretion of IL-1-β, TNF-α and VEGF--α. Intravital microscopic studies showed that topical application of MC-LR enhanced the numbers of rolling and adhered leukocytes in the endothelium of postcapillary mesenteric venules. The latter effects may be dependent upon induction of the synthesis and expression of L-selectin and -α2-integrin in neutrophils, as assessed by flow cytometry and RT-PCR, respectively. Conversely, the three toxins promoted direct locomotion of neutrophils and enhanced their migration in response to fMLP, as measured by Boyden chamber assays, and increased intracellular calcium, a messenger in the chemotaxic process. The effects of MC-LA, MC-YR and MC-LR in human neutrophils and mice had the same pattern of response. The analyses of cell viability, DNA fragmentation, mitochondrial membrane depolarization of and release of intracellular ROS were evaluated by the technique of FACS. Extracellular ROS content was measured by lucigenin-amplified chemiluminescence, and cytokines were determined by ELISA. We found that these MCs increased interleukin-8 (IL-8), cytokine-induced neutrophil chemoattractant-2αβ (CINC-2αβ) and extracellular ROS levels in human and rat neutrophils. In conclusion, our results showed that MCs act on specific pathways of neutrophil recruitment, indicating their potential effect on neutrophils activation. This process can significantly contribute to the pathogenesis of hepatic damage due to generation of ROS by neutrophils as well as act on hepatocytes under such conditions and potentially increase injury processes induced by MCs.

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21

Coldren, William Henry. "Theoretical Studies of Reactive Intermediates in Complex Reaction Mechanisms." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531497707269833.

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22

Nguyen, Thi Phuong Thu. "Polymer and surface modifications for antibacterial purposes." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS449.

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La contamination microbienne des surfaces est l’une des préoccupations majeures des secteurs d’activités comme l’industrie agro-alimentaire, la santé publique et les milieux hospitaliers. Face aux problèmes de santé publique liés à contamination bactérienne sur les surfaces, la préparation de surfaces aux propriétés antibactériennes est devenue un intérêt de recherche majeur pour de nombreux scientifiques et ce, dans de nombreux domaines de recherches. Du point de vue de la chimie, des matériaux et de la microbiologie, la fonctionnalisation des surfaces de matériaux polymères préexistants sans altérer leur propriété initiale est une solution séduisante. Pour cela, développer des nouveaux matériaux antibactériens/antifouling où la surface serait fonctionnalisée par des polymères antimicrobiens, greffés de manière robuste i.e. de façon covalente représente une solution idéale. Afin de faciliter et d’accélérer le processus de criblage, il est proposé dans ce travail une nouvelle approche pour obtenir des polymères ayant des propriétés antimicrobiennes à la fois en solution et à partir de la surface. Ce travail comprend une étude de (co)-polymérisations contrôlées d'esters actifs servant d’intermédiaires pouvant être post-modifiés pour synthétiser des polymères d'intérêts présentant les caractéristiques antimicrobiennes attendues.Ce travail démontre que la polymérisation radicalaire contrôlée en présence de Cu(0)/Cu(II) est une technique appropriée qui permet de préparer facilement des (co)-polymères réactifs, en solution mais aussi à partir de surface de poly (téréphtalate d’éthylène), communément appelé PET. Dans un premier temps, nous aborderons l'étude de la polymérisation contrôlée du méthacrylate de pentafluorophényle (PFPMA), avec son optimisation en solution, puis à partir de surface du PET porteuse de groupement d’amorçage. De plus, la polymérisation du méthacrylate de p-nitrophényle (NPMA) sera également examinée, ainsi que la copolymérisation des deux esters actifs là-encore par polymérisation de type contrôlée en présence de Cu(0)/Cu(II). La post-modification des polymères activés est ensuite présentée. La post-modification s’est révélée efficace et facile à mettre en œuvre. La structure et les caractéristiques des polymères obtenus ont été analysées et confirmées. Il est à noter que la post-modification a pu être effectuée par un processus séquentiel avec une fonctionnalisation simple ou avec plusieurs huiles essentielles, qui possèdent des propriétés naturelles antibactériennes ou antioxydantes. Différents films de PET ont été modifiés, des polymères aux propriétés anti-adhérentes ont été greffés par cette même méthodologie. Ces surfaces modifiées ont été testées contre deux bactéries modèles telles que Staphylococcus aureus et Pseudomonas aeruginosa afin de déterminer si les modifications de surface ont conféré au film de PET les propriétés biologiques attendues
Microbial contamination on surfaces has become major concern in various areas including industrial process as well as public health and hospitalization. Being aware of several problems causing by adherence and attachment of bacteria on a surface, preparation of antibacterial surface has become a global research interest for researchers in many domains. From the chemistry integrated with material science and microbiology point of view, functionalization of existing polymeric material surfaces is an attractive solution. In this domain, the surface functionalized with covalently grafted antimicrobial polymers represents an ideal solution. In order to facilitate the screening process, it is proposed in this particular research a new approach to obtain polymers with antimicrobial properties both in solution and from surface. The present approach includes a study in controlled (co)polymerization of active ester(s) serving as intermediate templates that can be eventually modified by polymer post-modification process to fabricate polymer of interest with expected antimicrobial characteristics.In general, it is demonstrated herein that the use of Cu(0)-mediated reversible deactivation radical polymerization (RDRP) is a suitable technique that allows facile preparation of reactive (co)polymers in solution and from surface of poly(ethylene terephthalate). First of all, this thesis focused on the study of controlled polymerization of pentafluorophenyl methacrylate (PFPMA) which appeared to be challenging. Furthermore, along with the optimization of polymerization in solution was the investigation of surface-initiated polymerization of this monomer from PET surface. Besides, polymerization of p-nitrophenyl methacrylate (NPMA) and copolymerization of the two active esters by Cu(0)-mediated RDRP were also examined. In addition, polymer post-modification of obtained (co)polymers with various compounds had been proven to be efficient, easy to perform. The structure and characteristics of obtained products were confirmed to match with expectations. It is remarkable that the post-modification can be done as sequential process, single or dual functionalization with several different essential oils, which are natural antibacterial or antioxidant compounds. On the other hand, the success in polymerization and post-modification of polymer of active esters in solution allowed the fabrication of different PET film grafted with polymers that are envisaged to have antiadhesion properties. Attempts to test such properties were also done against two model bacteria including Staphylococcus aureus and Pseudomonas aeruginosa to investigate if expectations are valid

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23

Bossion, Duncan. "Théories et simulations de collisions moléculaires réactives pour la chimie primordiale." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS090.

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Dans cette thèse, nous présentons l'analyse de la dynamique réactionnelle de systèmes triatomiques d'intérêt pour la chimie primordiale. Les simulations ont principalement été réalisées en utilisant le formalisme des trajectoires quasi-classiques (approche QCT) pour lesquelles un code a été développé. Celui-ci présente l'avantage de pouvoir déterminer des constantes de vitesse d'état-à-état avec un coût numérique raisonnable et pour une grande gamme de températures. Nous avons montré que les résultats QCT sont très appropriés notamment dans la gamme des énergies de collision élevées en réalisant un nombre limité de calculs quantiques dépendants du temps (méthode MCTDH). Un très grand nombre de constantes de vitesses (~ 300000) a été déterminé pour les systèmes H3, H2D caractéristiques de processus directs. Notre étude a par ailleurs révélé l'importance du processus de dissociation pour le régime des hautes températures (T > 10^3 K). Les nouvelles données cinétiques permettront de contraindre les abondances moléculaires de H2 et HD et ainsi de fournir des fonctions de refroidissement fiables pour l'étude de la dynamique d'effondrement des nuages moléculaires précurseurs des premières étoiles. Ces nouvelles données peuvent également être employées pour des régions du milieu interstellaire où les états moléculaires d'énergie interne élevée sont suffisamment peuplés (régions PDR ou chocs de type C). Nous présentons aussi la dynamique de réactions indirectes des systèmes H2D+ et HeH2+. Pour ces processus qui peuvent être caractérisés par un complexe intermédiaire à longue durée de vie, nous avons montré qu'une méthode quantique approchée (méthode RPMD), peut être très efficace pour déterminer la constante de vitesse thermalisée et représente ainsi une approche d'intérêt pour de nombreuses réactions en astrochimie
In this PhD we present the analysis of the reactive dynamics of triatomic systems of interest for the primordial chemistry. Simulations have been mainly done using the quasi-classical trajectory formalism (QCT approach) for which a code has been developed. iT has the advantage of being able to determine the state-to-state rate constants with a low numerical cost and a large temperature domain. We have shown that the QCT results are very reliable in the high collision energy domain by realizing a limited number of time dependent quantum method calculations (MCTDH method). A huge number of rate constants (~300000) has been determined for the systems H3, H2D, typical of direct processes. Our study also revealed the importance of dissociation for high temperature regime (T > 10^3 K). The new kinetic data will permit to constrain the molecular abundances of H2 and HD, hence giving reliable cooling functions for the dynamics study of collapse of the molecular clouds precursor of the first stars. Those data could be employed in interstellar medium in regions where high internal energy molecular states are relevantly populated (PDR or C-type shocks). We present the indirect reaction dynamics of the systems H2D+ and HeH2+. For those processes that can be characterized by a long lifetime intermediate complex, we have shown that a approximated quantu method (RPMD method) can be very efficient to determine thermalized rate constants and represents an interesting approach for many reactions in astrochemistry

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24

Perez-Rodriguez, Jacqueline. "ROLE OF OXIDATIVE STRESS AND T CELL HOMING IN THE DEVELOPMENT OF MURINE SYNGENEIC GRAFT-VERSUS-HOST DISEASE." UKnowledge, 2009. http://uknowledge.uky.edu/gradschool_diss/804.

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Syngeneic graft-versus-host disease (SGVHD) is induced by reconstituting lethally irradiated mice with syngeneic BM cells followed by a 21 day treatment with the immunosuppressive agent cyclosporine A (CsA). Clinical symptoms of the disease appear 2-3 weeks following cessation of CsA therapy and disease-associated inflammation occurs primarily in the colon and liver. The development of SGVHD is a complex process resulting from the cooperative interaction of multiple effector cell populations including NK cells, T cells and macrophages. TH1 cytokines (IL-12, TNF-α, IFN- γ), produced by these effector cells, serve as inflammatory mediators contributing to the pathogenesis of SGVHD. The SGVHD conditioning agents, irradiation and CsA, are both required for the development of disease and contribute to the production of oxidative stress. Time course studies revealed increased reactive oxygen and nitrogen species (ROS/RNS), as well as, increased colon mRNA levels for TNF-α and iNOS in CsA-treated versus control BMT animals. Since ROS/RNS are known to mediate CsA toxicity, studies were undertaken to determine the effect of oxidative stress on the induction of SGVHD. In vivo treatment with the antioxidant MnTBAP caused a reduction in colon mRNA levels for iNOS and TNF-α, as well as delayed disease development, suggesting a role for oxidative stress in the development of SGVHD. In addition, CD4+ T cells have been shown to play an important role in the inflammatory response observed in the gut of SGVHD mice. Time course studies revealed significant increases in the migration of CD4+ T cells as early as day 14 post- BMT into the colon of CsA mice as well as significant elevated mRNA levels of cell adhesion molecules. Homing studies revealed that a labeled CD4+ T cell line, generated from SGVHD mice, migrated in larger numbers into the gut of CsA-treated mice compared to control animals. This study demonstrated that CD4+ T cells responsible for the pathogenesis observed in murine SGVHD are present early after BMT in colons of CsA-treated mice, suggesting that during the 21 days of immunosuppression therapy functional mechanisms are in place that result in increased homing of effector cells to colons of CsA-treated mice.

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25

Marsh, R. J. "Kinematic modelling of non reactive and reactive collisions." Thesis, University of Sussex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270740.

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26

Slatculescu, Andreea M. "Immune Dysfunction Associated with Hemodialysis Modalities." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30493.

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Infection is a leading cause of death in hemodialysis patients, partly due to dysfunctional immunity. Frequent dialysis therapy improves patient outcomes and quality of life. We hypothesize that extended home hemodialysis (EHHD) also improves immune function compared to conventional in-hospital hemodialysis (CHD); therefore, we designed a prospective matching-cohort clinical study to assess serum inflammatory markers and the functional capacity of monocyte-derived dendritic cells (MDDCs) and T-lymphocytes. Serum CRP was decreased in EHHD patients suggesting that extended dialysis may decrease inflammatory solute/cytokine levels. Compared to controls, MDDCs from hemodialysis patients had similar endocytic capacity, expression of co-stimulatory molecules, and T-cell activation capacity. However, CHD was associated with the highest expression of CD83 and CD40. Activated T-cells in CHD patients also produced significantly more immunosuppressive IL-10 compared to EHHD patients and controls. Therefore, EHHD may improve immune function by decreasing inflammation, MDDC pre-activation, and synthesis of immunosuppressive cytokines.

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27

Pathak, Asmita, sanjay K. singh, and alok agrawal. "C-reactive protein is an atheroprotective molecule." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/139.

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The co-localization of plasma C-reactive protein (CRP) and atherogenic low-density lipoprotein (LDL) at the atherosclerotic lesions raises the possibility of a role of CRP in the disease process. In vitro, in its native pentameric structural form, CRP does not bind to oxidized LDL. However, in its non-native pentameric structural form, CRP is capable of binding to oxidized LDL. It has been proposed that CRP changes its structure at sites of inflammation to gain the oxidized LDL-binding activity. In vivo, native CRP is neither pro-atherosclerotic nor atheroprotective in animal models of atherosclerosis. We assumed that native CRP shows no effect because inflammatory microenvironment in the arterial wall in animal models of atherosclerosis is not appropriate and, therefore, the structure of CRP remains unchanged. Accordingly, we hypothesized that a CRP mutant, generated by site-directed mutagenesis, capable of binding to oxidized LDL without the requirement of any further structural change should show an effect on the disease. In the current study, we evaluated the impact of such a CRP mutant on the development of atherosclerosis employing LDL receptor knockout mouse model of atherosclerosis. We found that there was a two-week delay in the development of atherosclerotic lesions in the aortic root of mice treated with mutant CRP compared to mice that did not receive CRP. The development of atherosclerotic lesions in the whole aorta was also reduced; there was 30% reduction in the size of lesions in mice treated with mutant CRP. Overall, the data indicate that CRP is indeed an atheroprotective molecule.

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28

McGrady, Gerard Sean. "Studies of some reactive molecular fluorides." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258156.

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29

Barry, N. J. "Molecular beam studies of reactive collisions." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375059.

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30

Harris, Sean Anthony. "Studies of ion molecule reactive processes, electron impact ionisation, and inelastic collisions in state selected molecular beams." Thesis, University of Canterbury. Chemistry, 1997. http://hdl.handle.net/10092/7863.

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Alkali metal ion sources have been designed for the production of Li+, Na+ and K+ ion beams. The thermionic emission of alkali metal ions from heated synthetic zeolites is utilised to produce the alkali ions. As a precursor to crossed beam studies of the reactions of the alkali metal ions with spatially oriented symmetric top alkyl halides, the ion molecule chemistry of K⁺ with CH₃X and tertiary C₄H₉X where X= Cl or Br has been examined for collision energies up to 5 e V using a Drift Tube Mass Spectrometer. The electron impact ionisation cross sections for the inert gases, H₂, N₂, SF₆, CC1₃H and the molecules CH₃X where X= H, F, Cl, Br, I, have been measured. The ionisation efficiency curves for Ar, CH₄, CH₃F, CH₃Cl and CH₃Br from threshold up to 200 e V have been determined. The cross sections for the loss of hexapole focused upper Stark state molecules from ∣JKM〉 rotational state selected molecular beams of CH₃F, CH₃Cl and CF₃H have been measured. The upper Stark state molecules are defocused from the beam in rotationally inelastic collisions with a. scattering gas introduced to the hexapole. The long range attractive van der Waals interaction between the colliding species has been used to account for the magnitude of the cross sections from consideration of rotational transitions of the ∣JKM〉 state selected beam molecules where ∆M = ±1 or ∆J = ±1. The seeded beam technique has been used to determine the velocity dependence of the defocusing cross sections.

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31

Firth, N. C. "Molecular beam reactive scattering of fluorine atoms." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377732.

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32

Markillie, Gavin A. J. "Reaction dynamics of small polyatomic molecules." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363979.

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33

Chang, Xiaoyan. "Theoretical studies of molecule-surface inelastic and reactive scattering." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316664.

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34

Brinne, Roos Johanna. "Reaction dynamics on highly excited states." Doctoral thesis, Stockholms universitet, Fysikum, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-27122.

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In this thesis I have performed theoretical studies on the reaction dynamics in few-atom molecules. In particular, I have looked at reaction processes in which highly excited resonant states are involved. When highly excited states are formed, the dynamics becomes complicated and approximations normally used in chemical reaction studies are no longer applicable.To calculate the potential energy curve for some of these states as a function of internuclear distance, a combination of structure calculations and scattering calculations have to be performed, and the reaction dynamics on the potentials has been studied using both time-independent and time-dependent methods.The processes that have been studied and which are discussed in this thesis are ion-pair formation in electron recombination with H3+, dissociative recombination and ion-pair formation of HF+, mutual neutralization in H++F- collisions and dissociative recombination of BeH+. Isotope effects in these reactions have also been investigated. Our calculated cross sections are compared with experimentally measured cross sections for these reactions.

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35

McGonigal, Marianne. "Reactive chemisorption of molecular fluorine on Si(100)." Thesis, Massachusetts Institute of Technology, 1989. https://hdl.handle.net/1721.1/130998.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 1989
Includes bibliographical references (leaves 215-217).
by Marianne McGonigal.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Chemistry

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36

Andersson, Linnéa. "Linear-scaling Quantum Molecular Dynamics for Reactive Systems." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-450150.

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The purpose of this thesis is to demonstrate linear-scaling, energy stable, propagation of the electronic degrees of freedom in finite temperature ExtendedLagrangian Born-Oppenheimer Molecular Dynamics for reactive systems in aself-consistent charge density-functional tight-binding formulation. The inverse Jacobian kernel matrix in the electronic equation of motion is approximated using alow-rank combination of directional derivatives of the ground state residual function. For accurate and efficient kernel calculation in the simulation of reactive systems, the derivative direction vectors are chosen from a pre-conditioned Krylov subspace. The full Jacobian inverse pre-conditioning matrix can be represented in sparse form with a constant number of non-zeros per row independently of matrix size, which is a major result of this work as this allows linear-scaling, pre-conditioned kernel calculation in each molecular dynamics time step. Density matrix perturbation response evaluation from an implicit, recursive expansion of the Fermi-Dirac function is used to find the directional derivatives. The auxiliary matrix inverses computed in the implicit,Fermi-Dirac density matrix expansion are stored and reused for efficient response calculations.

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37

Yamamoto, Shinichiro. "Reactive Oxygen Species / Reactive Nitrogen Species-sensitive TRP channels : Molecular Activation Mechanism and Physiological Significance." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/124503.

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38

Murray, Catherine M. "A molecular recognition approach to binding hydrolysed reactive dye." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361274.

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39

Williams, Robert D. "Characterisation of molecular variations in human C-reactive protein." Thesis, Keele University, 2017. http://eprints.keele.ac.uk/3528/.

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The research described here focuses on the molecular variations, clinical significance and structural interactions of the innate immune protein, C-reactive protein (CRP). Monomeric CRP (mCRP) was produced through urea-induced dissociation, at an optimum concentration of 3M urea over a 10-week period. Dissociated samples were purified via size exclusion chromatography and confirmation was provided via Western Blot analysis. In contrast with previous published works, this mCRP retained the ability to reversibly bind to phosphocholine. Furthermore, the binding of mCRP with cell wall polysaccharide does not result in the generic precipitation trend as that seen with pentameric CRP (pCRP). Human serum samples with raised CRP levels ( > 100mg/L) were analysed (n =40) to determine whether circulating mCRP could be detected in vivo. All 40 samples tested positive for pCRP via Western Blot and ELISA analysis, with further quantification via the UV Spectrophotometer supporting the calculated pCRP levels. Monomeric CRP was identified in all the 40 patient samples tested, with an average value recorded of 0.88mg/L (SE = ±0.142). Informed by the results from in vitro mCRP studies, the mCRP displayed a molecular weight of approximately 25kDa based on size exclusion chromatography and Western Blot analysis and demonstrated an ability to reversibly bind phosphocholine. To our knowledge, we are the first to successfully purify and identify a monomeric form of CRP from human serum through these procedures. Crystallisation trials of in vitro produced mCRP and the complex of pCRP with C1qGHR and CWPS did not result in the growth of any protein crystals of sufficient diffraction quality. One crystal from the complex crystallisation trials diffracted to 9Å with follow up conditions currently being pursued. Furthermore, additional crystallisation trials from both experiments have generated potential conditions which may be refined in future research to produce high-quality diffraction grade crystals.

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40

Kadi, Malin. "Ultrafast Photo-induced Reaction Dynamics of Small Molecules." Doctoral thesis, Uppsala University, Department of Physical Chemistry, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3597.

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The main focus of this thesis is the investigation of the dissociation dynamics of aryl halides using femtosecond pump-probe spectroscopy. In the monohalogenated aryl halides, iodo-, bromo- and chlorobenzene, the rate of dissociation following excitation at 266 nm in the gas phase increased with increasing mass of the halogen atom. This process was assigned to predissociation of the initially excited singlet (π, π*) state via a repulsive triplet (n, σ*) state due to spin-orbit interaction. In addition to the predissociative mechanism, a direct dissociation channel was observed in iodobenzene. The rate of the predissociation in bromobenzene was found to be faster in the condensed phase than in the gas phase, which can be explained by solvent-induced symmetry perturbations. Ab initio calculations of the potential energy surfaces of the ground state and several low lying excited states in bromobenzene have been performed in order to verify the suggested mechanism. Substituting one of the hydrogen atoms in bromobenzene affected the predissociation rate significantly. In o-, m- and p-dibromobenzene the predissociation rate increased with decreasing distance between the bromine atoms in accordance with an increased spin-orbit interaction introduced by the bromine substituent. The fastest predissociation rate was observed in 1,3,5-tribromobenzene. With chlorine and fluorine substitution, inductive and conjugative effects were found to be of importance. In the o- and m-isomers of the dihalogenated aryl halides, an additional faster dissociation channel was observed. Guided by ab initio calculations of the potential energy surfaces in the dibromobenzene isomers, we ascribed the fast dissociation pathway to predissociation of an initially excited triplet state. Upon methyl group substitution in bromobenzene, the decreased lifetime of the initially excited state was attributed to an incresaed density of coupled states.

Another system which has been studied in the condensed phase is diiodomethane. Using Car-Parrinello molecular dynamics simulations we observed a prompt dissociation and subsequent recombination to the isomer, iso-diiodomethane, in acetonitrile solution.

Vibrational wavepacket dynamics in the C (¹Σ⁺) state of NaK were studied using a direct ionization probing scheme. A simple analytical expression for the pump-probe signal was developed in order to see what factors that govern direct ionization of the vibrational wavepacket. Our experimental data was consistent with a photoionization transition dipole moment that varies with internuclear distance.

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41

Bennett, Roger Alexander. "Stimulated dynamics and reaction of small adsorbed molecules." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388721.

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42

Samson, Paul Anthony. "Reaction dynamics of small molecules at metal surfaces." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366722.

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Adair, Kenneth Valloyd. "Diffusive, reactive and orientational dynamics of molecular systems using molecular Fourier imaging correlation spectroscopy /." view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?did=1251854551&sid=1&Fmt=2&clientId=11238&RQT=309&VName=PQD.

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Thesis (Ph. D.)--University of Oregon, 2006.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 103-108). Also available for download via the World Wide Web; free to University of Oregon users.

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Pollum, Marvin. "Applying Fundamental Photochemistry to Drive Drug Development: The Photo-Dynamics and Reactions of Sulfur-Substituted Nucleic Acids." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1481287737895585.

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Li, Jian-Mei. "Molecular structure and biochemical properties of an endothelial cell NADP oxidase." Thesis, King's College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272282.

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Hu, Wan-Ping. "Non-reactive scattering of rotational quantum state selected molecular beams." Thesis, University of Canterbury. Chemistry, 2000. http://hdl.handle.net/10092/7933.

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Non-reactive scattering of rotational quantum state selected molecular beams of symmetric top molecules has been investigated using electrostatic methods. Cross-sections for the defocusing of upper Stark-state molecules in a hexapole electric field have been measured for neat and seeded beams of CH3F with a range of polar and non-polar quencher gases. Calculations of the hexapole focusing voltages for specific rotational states facilitated the assignment of the defocusing cross-sections to individual rotational states in the beam. The technique of Molecular Beam Electric Resonance (MBER) spectrometry has been employed to detect and study individual rotational states, resulting in a dramatic improvement in quantum state resolution over the use of a single hexapole filter. Cross-sections have been measured for the relaxation of selected upper Stark states in beams of methyl halides with a range of polar and non-polar scattering gases. The application of MBER spectrometry to rotational state identification in beams of symmetric to molecules has been explored in this study. Information on the velocity, temperature, and rotational state distribution of the beam can be easily obtained from experimentation using this arrangement. It has also provided insight into the focusing properties of hexapole electric filters. Individual rotational quantum states in a beam of symmetric top molecules could be tagged using an MBER spectrometer for studies of rotational state dependent properties, such as the effect of rotational states in scattering studies. The collisional relaxation of upper Stark-state molecules in a beam could occur through several mechanisms. Cross-sections measured using the technique of MBER have been largely attributed to an Mᴊ changing process. The effects of the long-range attractive van der Waals interaction potential, the relative velocity dependence of the collision partners and the electric field dependence of the Stark energy have been considered in order to account for the magnitude of the relaxation cross-sections measured in this study.

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Apte, Vaijayanti. "Brain-reactive antibodies: molecular specificity and relationship to biological aging." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc798378/.

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Brain-reactive antibodies (BRA) increase in frequency with age in several mammalian species and may be involved in the pathogenesis of age-related dementia. In this experiment, the molecular specificity of BRA in mouse sera was determined using an immunoblot assay, and the relationship of BRA to longevity was studied by comparing the rate of formation of specific BRAs in diet restricted C57BL/6NNia, B6D2F1/NNia, and DBA/2NNia, genotypes which differ markedly in life-span.

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Müller, Astrid M. "Ultrafast reaction dynamics of polyatomic molecules probed by ionization." Diss., lmu, 2000. http://nbn-resolving.de/urn:nbn:de:bvb:19-5246.

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Pearce, Julie K. "Reaction dynamics of chlorine atoms with cyclic organic molecules." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441354.

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Mordaunt, David H. "Photodissociation dynamics of small atmospherically important molecules." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388430.

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Dissertations / Theses on the topic 'Reactive molecules'

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