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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Non-convalent functionalization of carbon nanotubes : From the organization of surfactants to the self-assembly ofporphyrins. / Fonctionnalisation non-covalente de nanotubes de carbone : De l'organisation des micelles à l'auto-assemblage des porphyrines.

Delport, Géraud 14 December 2016 (has links)
Ce manuscrit présente une étude expérimentale sur le processus de recouvrement de nanotubes de carbone mono parois en suspension micellaire par des molécules de colorants organiques. En raison des propriétés électroniques exceptionnelles et de la structure chimique carbonée de ces nanotubes, une modification de leur environnement physico-chimique a une grande influence sur leurs propriétés optoélectroniques. Les conséquences de cette fonctionnalisation de surface sont étudiées par des techniques de spectroscopie optique. Le procédé de fonctionnalisation non covalente de nanotubes par des molécules de porphyrines en milieu micellaire est détaillé selon trois axes de recherches complémentaires. Dans un premier temps, les aspects cinétiques de ce processus réactionnels seront discutés. En particulier, le rôle de l'organisation de l'environnement micellaire est mis en évidence. Cela permet de comprendre et de contrôler la durée de la réaction. Une étude thermodynamique de l'interaction nanotube/porphyrines sera ensuite détaillée. Le comportement associatif des porphyrines au cours de leur interaction avec le nanotube sera démontré. Dans un troisième chapitre, les caractéristiques spectrales de la porphyrine lorsqu'elle est adsorbée sur la surface de carbone seront discutées. Un modèle de couplage dipôle- dipôle est développé pour comprendre ces effets. Ce modèle permet de mettre en évidence / This manuscript presents an experimental study on the process of coverage of single-wall carbon nanotubes by organic dyes molecules. Due to the exceptional electronic properties and the monolayer carbon structures of such nanotubes, a modification of their physico-chemical environment has a great influence on their optoelectronic properties. The consequences of this surface functionalization are studied by means of optical spectroscopy. The process of non covalent functionalization of surfactant suspended nanotubes by porphyrin molecules is separated in three complementary studies. The first one details the kinetic aspects of this reaction process. In particular, the role of the organization of the surfactant environment will be highlighted. This allows to understand and control the reaction timescale. On the second hand, a comprehensive thermodynamic study of the nanotube/porphyrins interaction is performed. The associative behavior of the porphyrin during the interaction with the nanotube is evidenced. Then, the spectral characteristics of the porphyrin when it is adsorbed on a carbon surface is discussed. A dipole-dipole coupling model is developed to understand such effects. This model allows to highlight the geometry followed by the molecules when they are organized on the carbon template (nanotube or graphene).
272

Synthesis and Studies of Wide-Band Capturing BODIPY-Fullerene Based Donor-Acceptor Systems

Shao, Shuai 05 1900 (has links)
Artificial photosynthesis is the process, which mimics the natural photosynthesis process in order to convert solar energy to chemical energy. This process can be separated into four parts, which are antenna system, reaction center, water oxidation center, and proton reduction center. If we only focus on the ‘antenna system and reaction center' modules, expanding the absorption band in antenna system and generating long-lived charge separated state in reaction center are two fantastic strategies to design the molecules in order to improve the efficiency of the artificial photosynthesis process. In the first work of this dissertation, mono-18-crown-6 and mono-ammonium binding strategy was used to connect BODIPY- C60 supramolecular based donor–acceptor conjugates. The meso- position of BODIPY was modified by benzo-18-crown-6, and the 3, 5 methyl positions were replaced by two styryl groups, which covered additional donor (triphenylamine or 10-methylphenothiazine). The acceptor is a fulleropyrrolidine derivative, which included an ethyl ammonium cation. The absorbance wavelengths of the donor covered 300-850 nm, which is the visible/near IR region (wide band capturing). The ultrafast charge separation and relatively slow charge recombination was found from femtosecond transient absorption study. Next, a ‘two point' bis-18-crown-6 and bis-ammonium binding strategy was utilized to link BODIPY- C60 supramolecular based donor–acceptor conjugates. In this case, the meso- position of the BODIPY was modified by a secondary donor (triphenylamine, phenothiazine, or ferrocene). And the 3, 5 methyl positions were replaced by two styryl groups, which included benzo-18-crown-6. The acceptor (fulleropyrrolidine) was functionalized by bis-alky ammonium cations. The absorbance/ fluorescence emission titration and computational studies supported that the ‘two-point' strategy has stronger binding than ‘one-point' strategy. The relatively slow charge separation was found in these donor-acceptor conjugates. To extend the second work, a pristine BODIPY was linked to the meso- position of the BODIPY-bis-benzo-18-crown-6. When the acceptor (C60-bis- ammonium) was added to the system, a sequential energy transfer (EnT) followed by electron transfer (ET) process was performed. The energy transfer was found from absorbance/ fluorescence emission studies, and the photoinduced electron transfer was observed from femtosecond and nanosecond transient absorption study. This is a great mode to mimic the ‘antenna-reaction center' events of natural photosynthesis. In the last work of this dissertation, triplet sensitizers (I2BODIPY and I2azaBODIPY) covalently linked with a C60 to form the donor-acceptor system. In this work, triplet charge separated state (long-lived charge separated state) was expected. According to the femtosecond transient absorption studies, we observed the singlet charge separation was faster than the intersystem crossing process, that was the reason that only singlet charge separated state was found for I2BODIPY-C60, and no electron transfer was found for I2 azaBODIPY-C60.
273

Design of novel garnet persistent phosphors activated with lanthanide and chromium ions with tunable long persistent luminescence from visible to near infrared region / 可視域から近赤外域まで波長可変な長残光蛍光を示すランタニドとクロムイオン賦活新規ガーネット長残光蛍光体の設計

Jian, Xu 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第20460号 / 人博第810号 / 新制||人||194(附属図書館) / 28||人博||810(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 田部 勢津久, 教授 加藤 立久, 教授 吉田 寿雄 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM
274

Synthesis and Photophysical Studies of Self-Assembled Chromophores

Demshemino, Innocent Sunday 14 July 2020 (has links)
No description available.
275

The pharmacological and cellular effects of human somatostatin receptor homo- and heterodimerization /

Grant, Michael, 1976- January 2008 (has links)
No description available.
276

Characterization of histidine-tagged NaChBac ion channels

Khatchadourian, Rafael Aharon. January 2008 (has links)
No description available.
277

Detection and characterization of Huntingtin-protein interactions using resonance energy transfer methodologies

Dominguez Martinez, Marta 25 July 2023 (has links)
HTT ist ein Protein, das durch seine Verbindung mit mehreren Interaktionspartnern an einer Vielzahl von zellulären Prozessen beteiligt ist. Darüber hinaus verursacht eine Mutation im HTT-Gen eine Krankheit, die als Huntington-Krankheit (HD) bezeichnet wird. Aufgrund der gerüstbildenden Eigenschaften von HTT wurde eine Vielzahl von Studien durchgeführt, um potenzielle therapeutische Ziele zu identifizieren. Die auf dem Resonanzenergietransfer (RET) basierenden Ansätze sind jedoch im Bereich der Huntington-Krankheit noch nicht vollständig genutzt worden. Daher habe ich versucht, solche Ansätze in Interaktionsstudien mit dem HTT-Exon 1 (HTTexon1) und dem Protein in voller Länge zu bewerten. Ich habe eine Benchmarking-Studie mit einem zuvor beschriebenen Huntingtin-interagierenden Protein (HIP) und HTTex1 (Wildtyp und mutiert) unter Verwendung eines BRET-Ansatzes durchgeführt. Meine Studien bestätigten die binäre Interaktion zwischen HTTex1 und sieben Proteinen. Ich habe auch drei Interaktionen mit der mutierten Version von HTTex1 bestätigt. Zusätzlich bewertete ich die Interaktionen durch FRET-Messungen mit Hilfe der Durchflusszytometrie. Der zweite Teil dieser Arbeit zielte darauf ab, ein Hochdurchsatz-Screening für den Nachweis von Protein-Protein-Interaktionen (PPIs) mit HTT in voller Länge (FL) unter Verwendung von Biolumineszenz-Resonanz-Energie-Transfer zu etablieren. Auf diese Weise konnte ich die Wechselwirkung zwischen FL HTT und einer Bibliothek von 580 Proteinkinasen bewerten. Schließlich analysierte ich die Spezifität der entdeckten Wechselwirkungen, indem ich die unspezifische Bindung durch Donor-Sättigungstests bewertete. Zusammenfassend belegen meine Ergebnisse die potenzielle Verwendung von Resonanzenergietransferansätzen zur Validierung von HTT-Wechselwirkungen. Außerdem wird ein neues Screening-Tool vorgestellt, das dazu beitragen soll, HTT-Interaktoren zu identifizieren und zu verifizieren. / HTT is a protein involved in a plethora of cellular processes through its association with several interaction partners. Furthermore, a mutation in the HTT gene, causes a disease denominated Huntington’s disease (HD). Due to the scaffolding properties of HTT, a large variety of studies have been performed to identify potential therapeutical targets. However, resonance energy transfer-based (RET) approaches have not been fully exploited in the HD field. Therefore, I aimed to evaluate such approaches in interaction studies using the HTT exon 1 (HTTexon1) as well as the full-length protein. I performed a benchmarking study with a previously described huntingtin interacting protein (HIP) and HTTex1 (wild type and mutated) using a BRET approach. My studies confirmed the binary interaction between HTTex1 and seven proteins. I also confirmed three interactions with the mutated version of HTTex1. Additionally, I also evaluated the interactions by measuring FRET using flow cytometry. The second part of this work aimed to stablish a high-throughput screening for the detection of protein-protein interactions (PPIs) with full-length (FL) HTT using bioluminescence resonance energy transfer. With this, I was able to evaluate the interaction between FL HTT and a library composed by 580 protein kinases. Finally, I analysed the specificity of the detected interactions by assessing unspecific binding through donor saturation assays. In summary my results provide evidence of the potential use of resonance energy transfer approaches to validate HTT interactions. Additionally, a new screening tool is presented to contribute to identify and verify HTT interactors.
278

The Study of Coupling in InGaAs Quantum Rings Grown by Droplet Epitaxy

Alsolamy, Samar M. 12 June 2013 (has links)
No description available.
279

PHOTOCHEMISTRY AND PHOTOPHYSICAL CHARACTERIZATION OF PORPHYRIN & N-CONFUSED PORPHYRIN DYADS: PORPHYRIN PHOTOPHYSICAL PROPERTIES AND ELECTRON AND ENERGY TRANSFER

Alemán, Elvin A. January 2006 (has links)
No description available.
280

Collisional Dynamic Elements of the Pyrazine - N2O System:Middle and Low J States

Mix, La Moyne Tyler 05 January 2014 (has links) (PDF)
Unimolecular reactions based on the Lindemann - Hinchelwood mechanism are important to understanding combustion and atmospheric processes. The main feature of this mechanism is the energy transfer probability distribution function, P(E',E). We have chosen to study P(E',E) through gas phase collisional dynamics probed with IR transient absorption spectroscopy. Post-collision absorption line widths for the pyrazine-N2O system are used to calculate lab frame translational temperatures. The translational temperatures reveal that collisions with large rotational energy transfer also transfer large amounts of translational energy. For J states >47 the relationship is linear indicating a constant impact parameter. Line widths for J=47 through J=59 also showed that there is no out-scattering from these states, in contrast to work performed previously in the Sevy group. The discrepancy between these measurements prompted a complete analysis of the causes of noise in the experimental system. Defective instruments were identified and noise sources localized, including IR diode frequency jitter. Improved experimental techniques and troubleshooting guides are explained for future researchers in the Sevy group.

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