Dissertations / Theses on the topic 'Aggregation induced'
To see the other types of publications on this topic, follow the link: Aggregation induced.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Aggregation induced.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Klebensberger, Janosch. "Detergent-induced cell aggregation in Pseudomonas aeruginosa." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-26614.
2
Östman, Johan. "Mechanisms involved in amyloid induced cytotoxicity." Doctoral thesis, Umeå universitet, Molekylärbiologi (Teknat- och Medfak), 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-541.
Abstract:
Amyloidoses comprise a group of diseases where normal or mutated protein precipitates into amyloid fibrils. The deposition of fibrils causes dysfunction of organs and toxicity to nervous tissue. Up to date, 24 different proteins and peptides are known to be able to form amyloid fibrils. The most well known are Amyloid beta peptide and Prione protein causing Alzheimer’s disease and Creutzfeld Jacob’s disease respectively. The aims of this thesis were to investigate the structural properties of cytotoxic amyloid and examine the mechanisms involved. The model protein mostly used in the studies was the plasma protein transthyretin (TTR). Familial Amyloidotic Polyneuropathy (FAP) is a hereditary, autosomal-dominant neurodegenerative disease caused by point mutations in the TTR gene. One of the most common variants of FAP is a mutation in position 30 where alanine is exchanged for methonine. This gives rise to “Skellefteåsjukan” in Sweden. TTR is secreted into the plasma as a tetramer. Point mutations destabilize the tetramer leading to disassembled monomers, which undergo partial denaturation as an initiation step to aggregation and amyloid fibril formation. In vivo amyloidogenesis takes a long time and does not occur until late in adult life. Most of the clinical TTR mutations do not form amyloid in vitro under physiological conditions. We have created amyloidogenic TTR mutants that are prone to aggregate and form fibrils under physiological conditions. This provides us with a model system on the cellular level for studies of the mechanisms of amyloid associated cytotoxicity as we can control the aggregation process and capture defined stages in the TTR amyloidogenic pathway. We used Atomic Force Microscopy (AFM) to follow the morphology of aggregates during fibril formation. Initially, amorphous aggregates were formed that subsequently matured into fibrillar structures, denoted protofilaments. This observation was interpreted as an optimisation of ß-strand registers. In addition we identified a correlation between the presence of early-formed aggregates of TTR and cytotoxicity. The toxic response was mediated via an apoptotic mechanism. We were not able to more carefully determine the structure and size of the toxic TTR species. To address this problem we turned to another amyloidogenic protein, equine lysozyme (EL). Intermediate samples corresponding to the aggregation and growth phase of amyloid fibrils of EL were collected. These samples were subjected to cytotoxicity assays as well as monomeric starting material and mature amyloid fibrillar species. The results clearly showed that the soluble oligomers were cytotoxic in contrast to the monomers and fibrils. Our data indicate that the toxic properties of the oligomers are size dependent. In this thesis we asked the question whether all mutated forms of TTR can be expressed and secreted or if there is a selection against the most aggressive mutations in vivo? We transfected hematopoetic K562 cells with wild type or mutant TTR, with or without the N-terminal signal peptide, responsible for secretion, to generate both extra- and intracellular TTR. We show that the post-translational quality control of the cells does not allow intracellular mutant TTR outside the secretory pathway, possibly due to the cytotoxic effects, while translocated to the secretory pathway made it escape the quality control permitting secretion and amyloid formation outside the cells. We have further analyzed the cytotoxic mechanisms induced by TTR oligomers with a focus on intracellular apoptotic signalling pathways. We show that TTR oligomers bind to the surface of the target cells but are not taken up, that is in contrast to mature fibrils that do not bind them at all. The apoptotic response occurred in a caspase-independent and a free radical dependent way.
3
Menzen, Tim Andreas. "Temperature-induced unfolding, aggregation, and interaction of therapeutic monoclonal antibodies." Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-175200.
4
Nyström, Roger. "Aggregation of calcium carbonate dispersions induced by electrolytes and polyelectrolytes /." Åbo : Åbo akademi University, 2004. http://catalogue.bnf.fr/ark:/12148/cb40124838x.
5
Knight, Grady C. "The molecular chaperone α-crystallin protects proteins from UV-induced aggregation." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/30486.
6
Xu, Meisheng. "The field-induced aggregation and magneto-optical properties in magnetic fluids." Thesis, London South Bank University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300592.
7
Dong, Yujie. "Synthesis, photophysical properties and applications of aggregation-induced emission materials based on cyanostilbene moiety." HKBU Institutional Repository, 2016. https://repository.hkbu.edu.hk/etd_oa/313.
Abstract:
The concept of "aggregation-induced emission" (AIE) effect has induced a great deal of attention these days. Now, exploration of new AIE-active molecular system and multiple high technique applications for AIE materials are the two research hotspots. Cyanostilbene, as a classical structural unit in photoelectric functional materials, also exhibited this unique luminescence behavior. The research background was illustrated in Chapter 1, which mainly introduced the development of this subject. In this project, Chapter 2 and Chapter 3 presented two classes of functionalized AIE-active molecules based on cyanostilbene moiety, and their applications were investigated, while Chapter 4 demonstrated a series of donor-acceptor (D-A) molecules with highly emissive unit, and their photophysical properties were studied.;In Chapter 2, four different donor-substituted cyanostilbene-based dipyrrins were synthesized and characterized. The investigation of photophysical properties confirms that these molecules are AIE-active, which should be attributed to the cyanostilbene moiety. The introduction of different donor groups showed little impact on their luminescence. Furthermore, the emission properties of these molecules were found to be sensitive to Zn2+, that is, addition of Zn2+ enormously enhanced its fluorescence in THF. The titration experiments proved they showed good selectivity and sensitivity for Zn2+ detection with relatively low limit of detection. Job's curve and spectral studies of their corresponding zinc complex indicated that the ratio for dipyrrins and Zn2+ is 2:1, which suggested the formation of zinc complex by chelation-enhanced fluorescence (CHEF) effect should be the reason of the enhanced fluorescence. By combining dipyrrin with typical AIE-active moiety tetraphenylethylene (TPE), an AIE-active TPE-based dipyrrin was prepared. The studies of its fluorogenic Zn2+ detection confirmed that the CHEF effect together with AIE effect are responsible for the intense fluorescence, indicating the potential application as a Zn2+ detector in aqueous media.;In Chapter 3, the cyanostilbene backbone was functionalized with a terpyridine unit to construct four terpyridine-based cyanostilbene molecules with different donor substitutents. The investigation of their photophysical properties confirms that they are AIEE-active. With the effect of different electron-donating groups, their solid-state fluorescence color was adjusted from blue to orange-red successfully. According to the calculation results of their frontier molecular orbitals, terpyridine has little impacts on their luminescence, but would influence their solid-state emission obviously owing to its large steric hindrance. This class of molecules displayed higher luminescence efficiency in solid state than in their dissolved state. The twisted molecular conformation in single crystal, which effectively avoids close π-π stacking, was assumed to be responsible for the high luminescence efficiency in solid state. This kind of molecules show distinct switched fluorescence by stimuli of acid/base vapors, and this phenomenon derives from the protonation effect of nitrogen atoms in the terpyridine unit. Moreover, three of these molecules exhibit good electroluminescence properties. Especially, the crystal of non-donor substituted molecule show amplified spontaneous emission (ASE) properties, indicating this blue-emissive material can be used in multiple areas such as chemical sensor, organic light emitting diodes (OLEDs) and organic laser media.
8
Yu, Wai Hong. "Synthesis, Characterization and application studies of new aggregation-induced emission (AIE)-active materials." HKBU Institutional Repository, 2018. https://repository.hkbu.edu.hk/etd_oa/496.
Abstract:
The structural design, synthesis and characterization of luminogens with aggregation-induced emission (AIE) properties are studied in this thesis. The remarkable emission properties, thermal stability and biocompatibility of the AIE-active materials demonstrate the promising applications in bioimaging and organic light-emitting diodes (OLEDs).;Chapter 1 introduces the existence of aggregation-caused quenching (ACQ) effect in most conventional organic dyes as well as phosphorescent transitional metal complexes. Discovery of AIE and its mechanical study allow further exploration of usage in organic luminescent materials. This chapter also gives some examples and the applications these AIE-active compounds.;In Chapter 2, a series of cyanostilbenes with simple electron donor (D)-p-electron acceptor (A) structure are presented and synthesized. They exhibit remarkable AIE effect as well as deep red emission peak in 95 % water fraction in THF. These results indicate that attachment of these electron acceptors provides alternative strategy for designing highly emissive AIE-active materials.;In Chapter 3, strongly emissive cyanostilbenes with phenothiazine unit are designed and synthesized. This chapter also investigates the effect of substituents in phenothiazine and terminal cyanostilbene on the photophysical properties and AIE effect. The results suggest that they are AIE-active with different sizes in nano-aggregates. Furthermore, these dyes exhibit clear and strong fluorescence in live cell imaging with excellent biocompatibility.;In Chapter 4, a series of AIE-active phosphorescent Pt(II) complexes made up of C^N^C tridentate ligands are designed and synthesized. They exhibit different morphologies and emission properties upon aggregation in 90 % water in acetonitrile although similar tridentate ligands are applied. One of the complexes in this chapter show nano-rod formation with the highest quantum efficiency in aggregated state, suggesting that rapid self-assembly process occurs to prevent non-radiative decay and oxygen quenching.;In Chapter 5, a series of bis-cyanostyryl fluorophores are designed and synthesized. They are emissive in solid state with colour range from orange to NIR region. Furthermore, they are AIE-active and some of them may contain hybridized local and charge transfer (HLCT) excited state to achieve highly efficient emission upon solvatochromic investigation. Some bis-cyanostyryl thiophenes are fabricated in OLED devices show deep-red to NIR emission, indicative of a promising way to design solid-state NIR-emissive compounds using bis-cyanostyryl derivatives.;Finally, Chapter 6 and 7 present the concluding remarks and the experimental details of the work in Chapters 2 to 5, respectively.
9
Brummitt, Rebecca K. "Urea-induced dissociation of non-native aggregates of alpha-Chymotrypsinogen A kinetics, thermodynamics, and competing pathways /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 103 p, 2008. http://proquest.umi.com/pqdweb?did=1597632641&sid=12&Fmt=2&clientId=8331&RQT=309&VName=PQD.
10
Photchanachai, Songsin. "Studies on Molecular Aggregation and Degradation of Food Proteins Induced by High-Temperature Treatments." Kyoto University, 2003. http://hdl.handle.net/2433/148327.
Abstract:
Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第10507号
農博第1380号
新制||農||882(附属図書館)
学位論文||H15||N3862(農学部図書室)
UT51-2003-U477
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 北畠 直文, 教授 小川 正, 教授 吉川 正明
学位規則第4条第1項該当
11
Cassidy, James. "Parsing The Aggregation- and Photodegradation-Induced Effects of Rhodamine-Sensitized Tio2 and Zro2 Films." W&M ScholarWorks, 2017. https://scholarworks.wm.edu/etd/1499450063.
Abstract:
The impact of rhodamine aggregates on the photophysical properties of rhodamine dyes adsorbed to TiO2 were investigated using diffuse reflectance spectroscopy, steady-state fluorescence, and time-correlated single photon counting (TCSPC). Photocatalyzed de-alkylation of rhodamine dyes containing tertiary amine groups (5-ROX, R101, and RB) was observed on TiO2, which resulted in a ~50 nm hypsochromic shift. Therefore, concentration dependent diffuse reflectance spectra of R560/TiO2 samples, which contained primary amines, demonstrated the formation of H- and J-aggregates at the expense of the monomers. The formation of J-aggregates resulted in FRET between monomers and J-aggregates which yielded a bathochromic shifted fluorescence spectra as a function of increased dye concentration. Additionally, the J-aggregates were believed to be less fluorescent than the corresponding monomer, which, in addition to the presence of non-fluorescent H-aggregates, led to the quenched fluorescence. Time dependent fluorescent measurements established that electron injection to TiO2 from R560 occurred from both the monomer and J-aggregates, as lifetimes of each species on TiO2 were quenched relative to lifetimes on ZrO2.
12
Suenaga, Kazumasa. "Precise Control of Highly-Efficient Solid-Emissive Property of Boron Ketoiminate." Kyoto University, 2019. http://hdl.handle.net/2433/242531.
Abstract:
付記する学位プログラム名: 充実した健康長寿社会を築く総合医療開発リーダー育成プログラムKyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第21793号
工博第4610号
新制||工||1718(附属図書館)
京都大学大学院工学研究科高分子化学専攻
(主査)教授 田中 一生, 教授 秋吉 一成, 教授 大内 誠
学位規則第4条第1項該当
13
Xu, Alan. "Atomic scale characterisation of radiation damage and radiation induced precipitation in tungsten-rhenium alloys." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:1ae33661-c81f-4e77-a80c-bc12ed9123d9.
Abstract:
Tungsten is considered the prime candidate material for plasma facing components within fusion reactors. However, exposure of tungsten to neutron flux brings about transmutation of tungsten into by-products: Re, Os and Ta. Under increasing levels of radiation damage, irradiation induced clustering/precipitation takes place that embrittles and thus reduces lifetime of such tungsten components. This thesis was undertaken to explore this subject on a deeper level. There are three components to this study. The first part considers the effect of Re content on irradiation induced clustering. Lab-made plate W-xRe (x: 2, 5, 10 and 25at.%) alloys were exposed to 1.2, 3.9 and 33dpa, self-ion irradiated at 773K. Analysis of cluster number density and volume fraction found they increase with damage level and bulk Re content. Based on these trends and existing literature data, a hypothesis was proposed suggesting clusters originate from vacancy clusters. Also, at 33dpa, rod shaped clusters form in W-25Re alloys while spherical clusters are present in other alloys. The clusters show close correspondence with irradiation induced precipitates and appear to be precursor phase. In the second part of this thesis, the effect of Os and Ta on cluster formation and alloy mechanical properties is examined. Lab-made plate W-1Re-1Os and W-2Re-1Ta alloys were irradiated at 33dpa at 573 and 773K and compared against control W-2Re alloy. At 33dpa and 573K, the Os and Ta presence suppresses cluster formation. Both ternary alloys contain smaller cluster diameter, composition, number density and volume fraction than the W-2Re alloy. However, at 33dpa and 773K, Os and Ta have opposing effects on cluster behaviour. Os increases the cluster nucleation rate and raises irradiation hardening (compared to W-2Re). Meanwhile, Ta presence decreased cluster number density and reduced the irradiation hardening (compared to W-2Re alloy). As well, Ta showed no evidence of clustering, only Re clusters form in the W-2Re-1Ta alloy. The final aspect of the thesis analyzes the effect of material microstructure and external variables on cluster formation in W-Re alloys. Commercial wire form W-25Re alloy was irradiated at 1.2dpa at 573 and 773K as atom probe needles and bulk sample. The larger free surface on atom probe needle samples appears to act as a sink for self-interstitials and vacancies at both temperatures. The effect of grain size and dislocation density was examined by irradiating commercial W-5Re wire (0.5-1μm diameter) and plate (1-3mm diameter) samples (annealed and unannealed) to 33dpa and 573K. It was found grain boundaries and dislocations act as defect sinks at 573K. Additionally, radiation enhanced Re grain boundary enrichment was observed for first time. The effect of grain size on cluster behaviour at 773K was also analysed. Commercial wire and lab-made plate W-3Re, W-5Re and W-25Re alloys were irradiated to 33dpa at 773K. The larger grain boundary area in wire samples is suspected of acting as a sink for self-interstitials leaving more vacancies for promoting cluster formation compared to lab-made samples. The discoveries made in this thesis broaden our current understanding of irradiation induced phase formation in tungsten. Their implications on plasma facing component design are discussed as well as recommendations for improvements. Further, areas requiring further research in this field are also highlighted.
14
Ohtani, Shunsuke. "Creation of Emissive and Functional Materials Based on Fused-Boron Complexes." Kyoto University, 2021. http://hdl.handle.net/2433/261618.
15
Andersson, Karin, M. Pokrzywa, Ingrid Dacklin, and Erik Lundgren. "Inhibition of TTR aggregation-induced cell death : a new role for serum amyloid P component." Umeå universitet, Institutionen för molekylärbiologi (Medicinska fakulteten), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-65622.
Abstract:
BACKGROUND: Serum amyloid P component (SAP) is a glycoprotein that is universally found associated with different types of amyloid deposits. It has been suggested that it stabilizes amyloid fibrils and therefore protects them from proteolytic degradation. METHODOLOGY/PRINCIPAL FINDINGS: In this paper, we show that SAP binds not only to mature amyloid fibrils but also to early aggregates of amyloidogenic mutants of the plasma protein transthyretin (TTR). It does not inhibit fibril formation of TTR mutants, which spontaneously form amyloid in vitro at physiological pH. We found that SAP prevents cell death induced by mutant TTR, while several other molecules that are also known to decorate amyloid fibrils do not have such effect. Using a Drosophila model for TTR-associated amyloidosis, we found a new role for SAP as a protective factor in inhibition of TTR-induced toxicity. Overexpression of mutated TTR leads to a neurological phenotype with changes in wing posture. SAP-transgenic flies were crossed with mutated TTR-expressing flies and the results clearly confirmed a protective effect of SAP on TTR-induced phenotype, with an almost complete reduction in abnormal wing posture. Furthermore, we found in vivo that binding of SAP to mutated TTR counteracts the otherwise detrimental effects of aggregation of amyloidogenic TTR on retinal structure. CONCLUSIONS/SIGNIFICANCE: Together, these two approaches firmly establish the protective effect of SAP on TTR-induced cell death and degenerative phenotypes, and suggest a novel role for SAP through which the toxicity of early amyloidogenic aggregates is attenuated.Epub 2013 Feb 4.
16
Tabuchi, Arata. "Direct demonstration of involvement of protein kinase Cα in the Ca[2+]-induced platelet aggregation." Kyoto University, 2003. http://hdl.handle.net/2433/148479.
17
Ling, Karen Kar Yun. "The role of P2Y1̳ nucleotide receptor in agrin-induced AChR aggregation at the neuromuscular junctions /." View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202002%20LING.
Abstract:
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.On t.p. "1̳" is subscript. Includes bibliographical references (leaves 114-141). Also available in electronic version. Access restricted to campus users.
18
Merg, Martina [Verfasser]. "Aggregation during biopharmaceutical production of antibodies induced by UV radiation and interface exposure / Martina Merg." Ulm : Universität Ulm, 2017. http://d-nb.info/1131710495/34.
19
Arribat, Mathieu. "Acides aminés phosphole ou silole : vers de nouvelles sondes fluorescentes pour un marquage de peptide innovant." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS144.
Abstract:
La première partie de ces travaux de thèse concerne la synthèse d’acides aminés phosphole par formation d’une liaison P-C. Les propriétés de fluorescence (absorption, émission et rendement quantique) sont modulées à la fois par les différents substituants présents sur le phosphore (BH3, O, S…) ainsi que par le squelette aromatique du phosphole. Des couplages peptidiques modèles réalisés en solution et sur support solide démontrent la possibilité d’intégrer ces acides aminés dans des peptides d’intérêts. La deuxième partie concerne la synthèse de nouveaux phospholes fonctionnalisés ainsi que d’une nouvelle méthode d’accrochage pour les introduire sur différents groupes pendants (SH, NH2, OH) d’acide aminés et peptides via la formation de liaisons P-S, P-N ou P-O. La troisième partie de ce travail a consisté en la synthèse d’une nouvelle classe d’acides aminés tétraphénylsilole fluorescents qui présentent des propriétés d’AIE (aggregation-induced emission) et pourront être utilisés pour le marquage de peptides d’intérêtsThe first part of this work is focused on phospholyl amino acids synthesis by formation of a P-C bond. The fluorescent properties (absorption, emission and quantum yield) are modulated either by the substituent on the phosphorus atom (BH3, O, S, …) or by the aromatic skeleton of the phosphole. Peptide coupling in solution or on solid support were performed and showed the possibility to introduce such amino acids into peptide of interest. The second part of this work is dedicated to the synthesis of new functionalized phospholes for a chemoselective grafting on amino acid and peptides pendant groups (SH, NH2, OH) via PS, P-N or P-O bonds. The third part consists into the synthesis of a new class of tetraphenylsilole amino acids which exhibit AIE (aggregation-induced emission) fluorescent properties. Those compounds were successfully incorporated into di- an tri- peptides in solution and on solid support
20
Ito, Shunichiro. "Synthesis and Photophysical Properties of Functional Luminescent Materials Based on β-Diiminate Complexes Composed of Main-Group Metals." Doctoral thesis, Kyoto University, 2020. http://hdl.handle.net/2433/245840.
Abstract:
京都大学0048
新制・課程博士
博士(工学)
甲第22155号
工博第4659号
新制||工||1727(附属図書館)
京都大学大学院工学研究科高分子化学専攻
(主査)教授 田中 一生, 教授 秋吉 一成, 教授 古賀 毅
学位規則第4条第1項該当
Doctor of Philosophy (Engineering)
Kyoto University
DGAM
21
Dong, Lei. "Conception et synthèse de glyco-sondes fluorescentes pour des applications en détection." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1153/document.
Abstract:
Avec le progrès scientifique et les besoins sociétaux, diverses méthodes de détection spécifiques et sensibles des métaux, des protéines et d’autres biomolécules sont largement utilisées dans la protection de l’environnement, la surveillance des maladies, la pharmacothérapie, la production agricole, l’industrie et d’autres domaines importants. Les sondes fluorescentes sont largement développées sur la base des phénomènes de transfert d’énergie (ICT, PET, FRET) et appliquées par exemple à la détection de contaminants ou à l'imagerie cellulaire. Mais l’effet d’agrégation (ACQ) atténue généralement l’intensité de la fluorescence et limite ainsi les applications de sondes organiques (souvent peu solubles dans l’eau) dans l’imagerie cellulaire et les systèmes vivants. Par conséquent, le concept d'« agregated induced emission » (AIE) représente une solution à ces problèmes d’agrégation et plusieurs glycoclusters, glyco-sondes et glyco-complexes fluorescents ont été conçus et reportés pour des applications en analyse biologique. Notre premier projet visait à concevoir et à synthétiser des glyco-polymères fluorescents pour le ciblage cellulaire et l’adressage de médicaments, tandis que la fluorescence permettrait la détection des cellules ciblées. Pour surmonter l'effet ACQ et les interférences provenant de la fluorescence biologique naturelle, nous avons conjugué le dicyanométhylène-4H-pyrane (DCM) et le tétraphényléthène (TPE) afin d'obtenir des sondes fluorescentes (AIE) émettant dans le proche infrarouge. Les glycosides ont fourni une bonne solubilité dans l'eau et l'auto-assemblage a conduit à des systèmes de détection et à une imagerie des cellules cancéreuses. Les glyco-polymères à base de TPE ont été synthétisés à partir de monomères de TPE incorporant deux monosaccharides par conjugaison azide-alcyne (CuAAC) et ces monomères ont été polymérisés par des réactions de CuAAC ou thiol-ène. Les glyco-polymères à base de TPE ne présentaient malheureusement pas une assez grande longueur de chaîne (généralement moins de 7 unités) et les propriétés fluorescentes attendues ne pouvaient donc pas être atteintes. Nous avons ensuite conçu et synthétisé des glyco-dots auto-assemblés par des sondes DCM et des glycoclusters à base de TPE. Les glyco-dots ont présenté une hydrosolubilité élevée et une réponse sélective au peroxynitrite (ONOO-) à la fois in vitro et dans des analyses cellulaires. Les glyco-dots pourraient détecter ONOO- endogène et exogène, mais sans reconnaissance cellulaire spécifique. Nous avons conçu et synthétisé des sondes fluorescentes AIE pouvant s'auto-assembler avec des glycoclusters à base de TPE. Les glyco-dots résultants étaient facilement solubles dans l'eau et présentaient une sensibilité et une sélectivité excellentes pour la détection du thiophénol in vitro et dans des échantillons d'eau environnementaux.Nous avons finalement combiné les deux fragments TPE et DCM pour synthétiser un nouveau fluorophore AIE (TPE-DCM) avec émission à longue longueur d'onde. Ensuite, la conjugaison avec des glycosides par CuAAC a conduit à des sondes AIE fluorescentes à émission de longue longueur d'onde, avec une excellente solubilité dans l'eau. Une application à la détection de glycosidases in vitro et dans des dosages cellulaires ou sur des modèles animaux a été possible avec ces sondesWith scientific and social progress, various methods for the specific and sensitive detection of metals, proteins and other biomolecules are widely utilized in environmental protection, disease surveillance, drug therapy, agricultural production, industry and other significant areas. Fluorescent probes are widely developed based on ICT, PET, FRET and other fluorescence mechanisms, and applied to the detection of contaminants or in cell imaging. But the ACQ effect usually quenched the fluorescence intensity and thus limited the applications of organic probes in cell imaging and living systems. Therefore, the concept of aggregated-induced emission (AIE) appears as a possible solution to these problems and several fluorescent glycoclusters, glyco-probes and glyco-complexes were designed and reported for biological analysis. Our first project aimed to design and synthesize fluorescent glyco-polymers with multiple glycosides for cell targeting and drug delivery while fluorescence will allow the detection of the targeted cells. To overcome the ACQ effect and interference from natural biological background fluorescence, we conjugated dicyanomethylene-4H-pyran (DCM) and tetraphenylethene (TPE) to obtain near-infrared AIE fluorescent probes. The glycosides provided good water solubility and self-assembly in water led to detection systems and imaging cancer cells. TPE-based glycopolymers were synthesized from TPE monomers incorporating two monosaccharides by CuAAC conjugation and these monomers were polymerized by either CuAAC or thiol-ene “click” reactions. The TPE-based glycopolymers did not display a large chain length (typically less than 7 units) and the expected fluorescent properties could not be reached. We then designed and synthesized glyco-dots self-assembled by DCM probes and TPE-based glycoclusters. The glyco-dots displayed high water-solubility and selective response to peroxynitrite (ONOO-) both in vitro and in cell assays. The glyco-dots could detect endogenous and exogenous ONOO- but no specific cell recognition. We designed and synthesized AIE fluorescent probes which could self-assemble with TPE-based glycoclusters. The resulting glyco-dots were readily water soluble and displayed excellent sensitivity and selectivity for thiophenol detection in vitro and in environmental water samples. We finally combined both TPE and DCM moieties to synthesize a novel AIE fluorophore (TPE-DCM) with long-wavelength emission. Then conjugation with glycosides through CuAAC led to AIE fluorescent probes with long-wavelength emission, excellent water-solubility. Application to the detection of glycosidases in vitro and in cell assays or animal models was possible with these probes
22
Nylander, Sven. "Thrombin/ADP-induced platelet activation and drug intervention /." Linköping : Univ, 2005. http://www.bibl.liu.se/liupubl/disp/disp2005/med885s.pdf.
23
Menzen, Tim Andreas [Verfasser], and Wolfgang [Akademischer Betreuer] Frieß. "Temperature-induced unfolding, aggregation, and interaction of therapeutic monoclonal antibodies / Tim Andreas Menzen. Betreuer: Wolfgang Frieß." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://d-nb.info/1060632438/34.
24
Lau, Wai Sum. "Synthesis, characterization and application studies of cyanostilbene-based molecular materials with aggregation-induced emission (AIE) characteristics." HKBU Institutional Repository, 2014. https://repository.hkbu.edu.hk/etd_oa/70.
Abstract:
The molecular design, synthesis, spectroscopic and photophysical characterization of a series of cyanostilbene-based compounds are studied in this thesis. The thermal, electrochemical and aggregation induced emission (AIE) properties of these cyanostilbene-based compounds, as well as their application in organic lighting-emitting diodes, live cell imaging, chemical vapor sensor were investigated. Chapter 1 gives a brief introduction on the aggregation-caused quenching (ACQ) behavior of the conventional organic luminogens and the discovery and proposed mechanism of AIE phenomenon. Furthermore, some examples and the applications of these AIE compounds will be discussed. In Chapter 2, triphenylamine- and carbazole-containing cyanostilbene-based derivatives are presented. From the examination of the emission profile, they are all AIE-active through comparison of the photoluminescence intensity in dissolved and in aggregated states. Additionally, the calculation of the enhancement ratio (I/I0 – 1) of each fluorophore was performed in order to quantify its AIE effect. One of our cyanostilbene-based luminogens has achieved an enhancement ratio with a value of 1128. This cyanostilbene-based luminogens has also shown good performance in OLED investigation. In addition to the OLEDs application, the selected cyanostilbene-based luminogens with solid-state emission, cell-permeability and reversible switch-on/off capability have illustrated the positive result in live-cell imaging and chemical vapor sensing. Conjugated polymer with high molecular weight is the superior option by overcoming the weaknesses of low-molecular-weight luminogens with excellent thin-film form ability and comparatively simple and inexpensive fabrication processes. The design and synthesis of the cyanostilbene-based polymeric chromophores are described in Chapter 3. The polymerization of the AIE-active diacetylene ligands by connection of trans-[Pt(PBu3)2] unit at both ends has successfully retained their AIE behavior. In contrast, the ACQ problem has occurred on the polymers with organic spacers and the AIE-active ligands. From the DFT calculation on the Pt polymers and the blue shift of emission spectra in high water content suggested that the AIE phenomenon of Pt polymers is probably originated from the elimination of the non-radiative intramolecular charge transfer (ICT) process. Owing to the high demand in red-emitting materials in the applications of electroluminescent devices, fluorescent sensing and bio-imaging, effort has been made to design a system with the new chromophores with donor (D) – acceptor (A) system and thus to synthesize phenothiazine (D)-containing cyanostilbene (A)-based derivatives which are depicted in Chapter 4. Consistent with the conventional AIE-active luminogens with a successively climb of photoluminescence intensities in response to the increase of water proportion, phenothiazine-containing cyanostilbene-based derivatives has exhibited a V-shape fashion of emission intensity. It suggests that the emission of chromophores started to be quenched due to the increase of solvent polarity, overriding that of the molecular aggregation when a “small” volume of water is being introduced. While aggregate formation was dominant from the addition of a “large” amount of poor solvent, less polar local environment was created which suppressed the non-radiative transition to the ICT state and intensified the emission efficiency. Phenothiazine (D) – cyanostilbene (A) system has created a series of red-emitting chromophores with great tunability for the sake of achieving the desired emission color and better emission efficiency. To functionalize these AIE-active cyanostilbene-based chromophores, pyridine group was attached to the compounds to take the advantage of its metal-chelating capability, which is discussed in Chapter 5. The AIE features of cyanostilbene-based compounds can be preserved after the introduction of the pyridyl unit. Even it possessed a weak photoluminescence in its dilute solution which suggest that the high electron delocalization within the molecule has rigidified the structure to some extent, it is transformed to a highly emissive state with a high proportion of water. The exclusive variation of emission behavior with obvious bathochromic shift and boost of emission spectrum in the presence of cadmium-(II) ion has demonstrated its potential metal ion sensing ability. Chapter 6 and 7 present the concluding remarks and the experimental data of the compounds of Chapter 2 to 5, respectively.
25
Wang, Jin-Hui. "Rhenium complexes based on triazolyl derivatives : from synthesis, structural and theoretical characterization to application as radiopharmaceuticals or fluorophores." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30329/document.
Abstract:
Les complexes de rhénium jouent un rôle important dans le domaine de la médecine nucléaire. Si pendant longtemps le rhénium a été utilisé comme modèle structural du technétium-99m, les caractéristiques physiques prometteuses des isotopes 186Re et 188Re, font des complexes de 186/188Re des candidats prometteurs en tant que radiopharmaceutiques thérapeutiques. De même, les propriétés intéressantes de photoluminescence des complexes de rhénium non-radioactifs en font d'excellents outils comme catalyseurs, matériaux luminescents et capteurs d'imagerie. Dans ce travail, notre objectif était (i) de développer, en utilisant une stratégie de chimie Click, des ligands multidentes pour la stabilisation de différents cœurs rhéniés de type [Re(CO)3]+ et [ReO]3+ (M = Re ou 188Re) ainsi que pour les coeurs analogues à base de 99mTc dans certains exemples, (ii) d'évaluer le potentiel des complexes de rhénium (technétium) en tant que sondes d'imagerie (Re naturel ou 99mTc) ou agents thérapeutiques (188Re). Pour ce faire, deux systèmes de chélatants spécifiques du rhénium (technétium) ont été utilisés: un système tripodal semi-rigide dans le deuxième chapitre et un fragment pyta au troisième chapitre, ces deux chélatants ayant été développés précédemment dans notre groupe. Ainsi, sur la base d'un ligand click tridente de type N2O, deux études différentes ont été réalisées dans le chapitre II. Dans la première étude, deux voies de synthèse ont permis de préparer une famille de ligands potentiellement tétradentes de type N3O, conçus pour coordonner les cœurs rhéniés aux états d'oxydation + I et + V. Les études de coordination envers ces différents noyaux de rhénium, ont également été étudiées. Les premiers résultats de radiomarquage combinés aux récents travaux rapportés par l'équipe de Dugave[xii] sur des systèmes similaires indiquent que ce ligand pourrait être un chélatant prometteur pour le 99mTc...voire le 188Re. A court terme, l'extension du radiomarquage au coeur [188ReVO]3+ devra être effectuée et la stabilité in vitro du complexe radioactif testée dans des conditions physiologiques classiques, dans le plasma humain et par des expériences d'échange de cystéine. La deuxième étude portait sur le développement de nouveaux radiopharmaceutiques du 99mTc sélectifs contre l'hypoxie. Notre ligand tripodal de départ a été décoré avec un groupe nitro (soit un groupe nitrobenzyle ou une entité métronidazole (Mtz)). Des positions différentes ont été considérées mais seulement deux ligands contenant du métronidazole (Mtz) et un ligand contenant un groupe nitro ainsi que les complexes correspondants de tricarbonylrhénium(I) ont été obtenus et caractérisés, notamment par électrochimie. Les potentiels de réduction du groupe NO2 dans les complexes [Re(CO)3Cl(L2)] et [Re(CO)3(L6)] sont similaires à ceux reportés dans la littérature pour des complexes de rhénium(I). Le chapitre III est axé sur l'étude de l'effet AIE (émission induite par l'agrégation) dans les complexes tricarbonylrhénium(I), l'association de cet effet avec les propriétés intrinsèques des complexes de Re(I) pouvant conduire à des composés très attrayants. Pour ce faire, nous avons combiné un fluorophore organique (motif benzoxazole ou PBO) qui présente une excellente stabilité et des propriétés optiques intéressantes, avec un complexe tricarbonylrhénium(I) basé sur une unité pyta (soit le 2-pyridyl-1,2,3-triazole ou le 2-pyridyl-1,2,4-triazole). Quatre composés ont été étudiés. Les structures RX ont révélé des différences structurales spectaculaires entre les deux premiers complexes, ReL8 et ReL9. Cette étude étant une nouvelle orientation dans notre groupe, ce travail sera un excellent point de départ pour d'autres recherches. Divers colorants organiques et/ou des modifications structurales de la fraction organique seront bientôt pris en compte pour développer des sondes luminescentes de rhénium(I) hautement émissivesRhenium complexes play a significant role in nuclear medicine. Rhenium has been widely used as a surrogate of technetium for a long time, and the promising physical features of 186Re and 188Re, make 186/188Re-complexes promising candidates as therapeutic radiopharmaceuticals.Similarly, the interesting photoactive and photoluminescence properties of non-radioactive Re-complexes make them excellent catalysts, luminescent materials and imaging sensors.Thus, in this work, our goal was to (i) develop, using a click chemistry strategy, multidentate ligands for the stabilization of different rhenium cores [Re(CO)3]+ and [ReO]3+ (M = Re or 188Re) as well as the analogous 99mTc-cores in some examples, (ii) assess the potential of the rhenium(technetium) complexes as imaging (natRe or 99mTc) or therapeutic (188Re) agents. To do so, two rhenium(technetium) specific-chelating systems were used: a semi-rigid tripodal system in the second chapter and a pyta moiety in the third chapter, these two chelators being developed previously in our group. Thus, based on a N2O tridentate click ligand, two different studies were carried out in chapter II. In the first one, two synthetic pathways to a range of potentially N3O tetradentate ligands, designed to coordinate rhenium cores as well as their coordination behaviors towards different rhenium cores (oxidation states +I and +V), were investigated. The first radiolabeling results combined with the recent work reported by Dugave and co-workers indicated that this ligand could be a promising 99mTc-chelator for nuclear imaging applications. As perspectives to this work, the extension of the radiolabelling work using the [188ReVO]3+ core should be performed, and the in vitro stability should be tested under physiological conditions in human plasma and by cysteine exchange experiments. The second study was focused on the development of novel hypoxia-selective 99mTc radiopharmaceuticals. Our semi-rigid tripodal click framework was decorated with an appended nitro group (either a nitrobenzyl group or a metronidazole (Mtz) unit). Different positions were considered and at least only two metronidazole (Mtz)-containing ligands and one nitro group-containing ligand as well as their corresponding tricarbonyl rhenium(I) complexes were obtained and characterized, in particular by electrochemistry. The reduction potentials of NO2 group in complexes [Re(CO)3Cl(L2)] and [Re(CO)3(L6)] were similar to those of reported hypoxic imaging agents, prompting us to further investigate other properties of these complexes. Chapter III was focused on the study of AIE (aggregation-induced emission) effect in tricarbonyl Re(I) complexes, the association of this effect with the intrinsic properties of Re(I) complexes being expected to lead to very attractive compounds. To do that, we combined an organic fluorophore (PBO) which exhibits excellent stability and optical properties, with a tricarbonylrhenium(I) complex based on a pyta unit (either a 2-pyridyl-1,2,3-triazole or a 2-pyridyl-1,2,4-triazole ligands). Four compounds were studied. The X-Ray structures revealed spectacular discrepancies between the two first triazole-based complexes ReL8 and ReL9. Moreover, this study being a novel orientation in our group, this work is a great starting point for further investigations. Various organic dyes and/or structural modifications of the organic moiety will soon be considered in order to develop highly emissive rhenium(I) luminescent probes
26
Tominaga, Masato. "Functional π-Conjugated Materials Based on Structure of o-Carborane." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188607.
27
Weir, Steven. "Effect of fermentation media on the polymer-induced aggregation of microorganisms and the effect on subsequent centrifugation." Thesis, University of Huddersfield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261466.
28
Upamali, Karasinghe A. Nadeeka. "Carbazole-Based, Self-Assembled, Π-Conjugated Systems As Fluorescent Micro And Nanomaterials - Synthesis, Photophysical Properties, Emission Enhancement And Chemical Sensing." Bowling Green State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1323099511.
29
Dong, Wenyue [Verfasser]. "The Design and Synthesis of Conjugated Polymers with Aggregation-Induced Emission and Their Application in Fluorescence Sensing / Wenyue Dong." Wuppertal : Universitätsbibliothek Wuppertal, 2015. http://d-nb.info/1076929885/34.
30
Dewsbury, Bryan M. "Artificially induced aggregation of fauna and their effects on nutrient regimes and primary producers in an oligotrophic subtropical estuary." FIU Digital Commons, 2006. http://digitalcommons.fiu.edu/etd/2786.
Abstract:
In order to investigate the role of faunal aggregations in concentrating nutrients in the oligotrophic landscape of Florida Bay, I manipulated faunal densities in Florida Bay sea grass beds by constructing artificial reefs. The effects of reefs and faunal aggregations on nutrient availability and benthic community structure were assessed.
Over a year-long sampling period, artificial reefs had an average population of 50 fishes and crustaceans of various species. Faunal aggregation resulted in significant sediment organic matter decreases and sediment phosphorus increases. Plots with high fauna populations also had shorter seagrass blades presumably due to the effects of grazing. Chlorophyll-a concentrations in the sediment and periphyton samplers were mainly affected by reef presence or exclosure type and not due to the presence of aggregating fauna. Our results suggest that faunal aggregation may have more top-down effects on primary producers than bottom-up effects over smaller temporal scales.
31
Yoshii, Ryosuke. "Synthesis of Highly-Functional Polymers Using Characteristics of Four-Coordinated Boron-Complexes with Boron-Nitrogen Bonds." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188610.
32
McKeon, Kristin Dianne. "Albumin Adsorption: Inferences of Protein Interactions Measured by Sedimentation both Between Species and Induced by Denaturing." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/32082.
Abstract:
Biological development and progression are managed by a diverse macromolecular group called proteins. Protein structure results from a complex folding process that leads to a final active form. This protein state is susceptible to changes in the surrounding environment and an incorrect structure can be produced. Changes in the protein conformation can lead to the formation of protein aggregates. Adsorption of proteins onto surfaces is utilized in many research analyses, but is capable of irreversibly changing the protein structure and causing aggregation. Albumin is a plasma protein that adsorbs on many different surfaces because the structure easily rearranges. The structure of albumin once adsorbed has been shown to deteriorate; however, outcomes of both stabilization and aggregation have been found.
A dynamic laser light scattering instrument will be utilized to measure the differences in size and determine the amount of aggregation. Our lab has developed a z-axis translating laser light scattering device (ZATLLS) that has been used to measure the sedimentation velocity of several different materials in solution. In this case, bovine serum albumin (BSA) will be adsorbed onto polystyrene particles and the particle settling velocity determined. The settling solution viscosity and density will also be ascertained, so Stokeâ s law can infer the average aggregate size of each experiment. BSA-coated polystyrene particles displayed a more controlled settling behavior compared to non-coated polystyrene particles. Although the BSA-coated particles had a smaller sedimentation velocity, a larger aggregate size was found due to the greater solution viscosity. Therefore, the ZATLLS instrument can be employed to measure sedimentation velocities of multiple interactions and the aggregation level inferred.
Although most albumin molecules are remarkably similar, there are subtle differences in amino acid residues, length, and charge. Sedimentation velocities for human serum albumin (HSA) coated polystyrene particles and BSA-coated polystyrene particles only had a small difference. However an almost 50% higher solution viscosity was measured in BSA experiment solutions, and resulted in the slower settling of the larger aggregates compared to HSA-coated particles. Viscosity calibration curves for each albumin species were used to determine the amount of protein desorbed from the particles during the settling process. The larger solution viscosity for BSA-coated particle experiments led to a much larger degree of desorption. HSA was shown to be the more stable albumin species when adsorbed onto polystyrene particles.
Temperature denaturing was performed to aid in the determination of the stability of BSA. Reversible and irreversible conformational changes in BSA were produced at 46ºC and 76ºC respectively. The solutions were cooled to room temperature before adsorption onto polystyrene particles and the sedimentation velocities measured. A 50% difference in average viscosity between the reversibly and irreversibly changed BSA was found. This caused the larger aggregates formed in the 76ºC BSA experiments to have an almost equivalent sedimentation velocity to those in the reversibly denatured BSA experiments. Average aggregate size for reversibly denatured BSA was well within the ranges found for non-denatured BSA. In conclusion, irreversibly denatured BSA formed larger aggregates and was more likely to desorb from the polystyrene particles than reversibly changed BSA.
Master of Science
33
Abeyawardhane, Dinendra L. "Biometal-Induced Structural Consequences of α-Synuclein – the Parkinson’s Disease Protein." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/5909.
Abstract:
The pre-synaptic protein α-Synuclein (αS) is often linked to the pathology of Parkinson’s disease (PD), an age-related neurodegenerative disorder. Lewy bodies, the cytopathological hallmarks of PD, are found to be rich in aggregates of misfolded αS protein. Metal dyshomeostasis has also been linked to PD due to the accumulation of iron in the substantia nigra pars compacta, and diminished copper levels reported in this same region. Metal dyshomeostasis in the brain coupled with oxidative stress can enhance the aggregation of αS. Recently, it was confirmed that mammalian αS is universally acetylated at the N-terminus, a common post-translational modification in humans. The consequences of this modification have been understudied, and it is believed to impart a functional role under physiological conditions with respect to membrane-interactions and protein folding. In an attempt to elucidate the pathological mechanism behind PD with respect to the structural dynamics of the protein, our investigations were focused on physiologically prevalent, N-terminally acetylated αS (NAcαS) and its interaction with the most prevalent redox-active metal ions in the brain (iron and copper) under both aerobic and/or anaerobic conditions.
The structural features associated with metal-bound NAcαS differed depending on the iron oxidation states, where under aerobic conditions Feᴵᴵ stabilized an oligomer-locked, anti-parallel right-twisted β-sheet conformation that could potentially impart toxicity to neurons. In contrast, Feᴵᴵᴵ promoted a fibrillar structure rich in parallel β-sheets. N-terminal capping also altered the Cuᴵᴵ coordination sphere and had a dramatic effect on protein aggregation. Parallel studies on NAcαS variants with different site mutations near the putative copper binding sites (ex: H50Q and F4W) indicated that preferential binding shifts upon changes in the side chain residues. In depth analysis of the electron structure of Cuᴵᴵ-bound NAcαS using electron paramagnetic resonance spectroscopy (EPR) revealed a coordination sphere of N3O1 that includes the H50 residue in the wild-type protein that shifts to an O4 coordination sphere at the C-terminus upon Cuᴵᴵ binding to the disease-relevant H50Q variant. Immunoblotting analyses revealed that copper-induced redox chemistry promoted O2-activation and the subsequent formation of dityrosine crosslinks, a post-translational modification identified as a biomarker of PD. EPR-detection of tyrosyl radical formation in the presence of Cuᴵ-bound NAcαS further supported this radical coupling mechanism. Intermolecular crosslinks within the fibrillar core of NAcαS as well as intramolecular crosslinks within the C-terminal region underpin the role of metal-dioxygen chemistry in PD-related pathology.
The unique structural features resulting from iron vs copper coordination to NAcαS inspired studies directed at the synergistic effect of each individual metal species as revealed by photo-initiated crosslinking of NAcαS. C-terminal intramolecular tyrosine interactions were mainly impacted by the presence of both metals, which each have binding sites around the same region. These findings emphasize that protein dynamics, metal binding site conformational changes, as well as aggregation pathways can deviate drastically upon N-terminal acetylation of αS and that protein-metal interactions may play a vital role in PD etiology.
34
Shorikova, D. V. "The collagen-induced platelet aggregation and artery status in patients with arterial hypertension and heart failure with preserved ejection fraction." Thesis, БДМУ, 2021. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/18601.
35
Viglianti, L. "THE HETEROARYLETHENES: SYNTHESIS, ELECTROCHEMISTRY AND INVESTIGATION ON THE AGGREGATION-INDUCED EMISSION OF A PROMISING CLASS OF MOLECULES WITH LUMINESCENT PROPERTIES." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/338784.
Abstract:
The present research has been aimed on the synthesis and to the electrochemical and photophysical investigation of the HeteroArylEthene class constituted by the DiThienylEthene DTE, TriThienylEthene TrTE, TetraThienylEthene TTE, DiFurylEthene DFE, TriFurylEthene TrFE and TetraFurylEthene TFE. The study includes as a benchmark the analogous phenyl-based series which was already well known concerning the synthesis the photophysical properties and the applications. A very limited knowledge was so far available concerning the heteroaryl-based ethenes. Among the investigated systems, TFE and TrTE are entirely new compounds and have been never investigated before; the other structures had already been reported in literature but only obtained by McMurry coupling, while in this work we have proposed a convenient alternative approach (besides significantly improving the McMurry protocol). Moreover, a deep electrochemical and photophysical characterization was still lacking; as a consequence, the highly interesting electrochemical and photoluminescence properties remained concealed until the study performed in this PhD research work, by which interesting features have been unearthed. In particular the investigate molecules have shown efficient π-conjugation emission and electropolymerization ability and the excellent property of the luminescence in solid state. So besides performing a detailed electrochemical investigation of the synthesized family members in terms of redox properties and electrooligomerization ability, we particularly concentrated on their photophysical investigation in terms of Aggregation-Induced Emission features. The latter has been performed in a seven-month stage at the Hong Kong University of Science and Technology, in the laboratories of Professor Ben Zhong Tang, the discoverer of the AIE phenomenon. The results obtained are of high interest and applicative potential. Thus systematic study performed in this thesis now provides a deep knowledge about the heteroarylethene properties which can allow to properly design more complex systems in which these scaffold could be used as starting block. In addition, their unique property of emitting light in solid but not in solution, renders them even more appealing, as small single molecule to be employed in hi-tech applications.
36
Deng, Jiun-Ping, and 鄧君屏. "Shear induced aggregation in liquid suspensions." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/77288998096356858609.
Abstract:
碩士長庚大學
化工與材料工程研究所
93
The aggregation of an initially well-dispersed suspension of particulates due to shear-induced collision is examined in laminar flow and in turbulent flow. Experiments in laminar flow are conducted by a cone-and-plate device on latex particles suspended in aqueous glycerol while experiments in turbulent flow are conducted by stirred tank. The corresponding shear rate in laminar flow and in turbulent flow is calculated as a function of the stirring rate. The rate of aggregation growth is measured as a function of time for different constant shear rate and suspension compositions. The experimental results show that the aggregate size increases rapidly in the early stage and then gradually reaches an equilibrium value due to the influence of hydrodynamic shear forces. An aggregation model is developed in this work to recover the collision efficiency and the equilibrium aggregate size from the experiment data.
37
Lee, Tai-chun, and 李岱軍. "Conformation Induced Molecular Aggregation in Poly(3-hexylthiophene)." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/54207782765945143457.
Abstract:
碩士輔仁大學
化學系
98
In this research, we’d like to study the morphology of P3HT in solution by controlling spin rate in solution state and also its morphology in films. UV-Vis and PL were used to monitor the state of aggregation under different shear force. Viscosity measurements were conducted to elucidate molecular conformation of P3HT in solution and to explain the results from UV-Vis and X-ray measurements. We found morphology of films prepared by aggregation of P3HT itself in solution was different from that prepared by extra shear force. Aggregation of P3HT itself in solution was destroyed during the film formation by spin-coating process. Packing of P3HT by extra shear force was maintained during the spin-coating process because shear force pushed the P3HT molecules in helical form to pack together tightly furing the stirring process. The results were different by using different solvents and they are related to the conformation of P3HT in solution. With this concept of organic solar cells can be used to process the above. We can create without annealing can produce highly ordered P3HT in close gatherings of activity layer, in order to save resources in the production of batteries and costs.
38
Lin, Li-yang, and 林利陽. "Polypeptides containing luminescent units with aggregation-induced emission property." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/j25965.
Abstract:
碩士國立中山大學
材料與光電科學學系研究所
103
First chapter: Tetraphenylthiophene (TP) with aggregation-enhanced emission (AEE) property was used as terminal fluorophore of the water-soluble poly(γ-propargyl-L-glutamate) (PPLG)-based polymers of TP-PPLG-g-MEO2. In this study, we research various TP-PPLG-g-MEO2 affect aggregation of luminescence. In water, when concentration of TP-PPLG-g-MEO2 achieve CMC, TP-PPLG-g-MEO2 will aggregation to nanoparticle and suddenly increasing emission, and when heating over LCST, TP-PPLG-g-MEO2 will contract and also enhance emission. We use TP-PPLG-g-MEO2 “salt out effect” property to probe salt in water, salt have interaction with side chain MEO2 and peptide main chain to make TP-PPLG-g-MEO2 contract together and change secondary structure to b-sheet conformation to enhance emission. In the strong alkaline media, TP-PPLG-g-MEO2 backbone change to random coil conformation that break intramolecular hydrogen bonding and loss LCST property, TP-PPLG-g-MEO2 become is a micelle like structure, core was hydrophobic TP and shell was hydrophilic polypeptide and particle size about 500nm measure by DLS. In random coil conformation, chain end hydrophobic TP have strong aggregation than in the a-helical and have strong aggregation emission peak. At last, we use TP-PPLG-g-MEO2 to detect BSA. When TP-PPLG-g-MEO2 mixture with BSA, TP-PPLG-g-MEO2 will fall in to BSA and separate to decrease TP-PPLG-g-MEO2 aggregation and emission. Second chapter: We synthesis polypeptide contain TPA pendent by click reaction. The resulting PPLG-g-TPA contains the crystalline TPA side groups, Tm about 145 oC and is therefore high Tg materials with the desired AIE activity. Due to side chain TPA, PPLG-g-TPA have piezofluorochromic property that have two color between crystal and amorphous state. The lone pair electrons of nitrogen atom in TPA side groups inherit PPLG-g-TPA the sensitivity toward acid HCl and metal ions. Emission of PPLG-g-TPA was progressively decreased upon increasing the amounts of HCl and metal ions in the solutions that can be acid or metal ions sensor.
39
Chang, Jui-Wen, and 張瑞文. "Aggregation-Induced Emission Characteristics of Tetraphenylethene-Capped Dipeptide Materials." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/43nzds.
Abstract:
碩士國立交通大學
材料科學與工程學系所
103
Supramolecular self-assembly hydrogel materials is ubiquitous in materials science and biology. Self-assembly provides routes to a range of materials with regular structures. And others advantages to developed in this process. In this thesis, we developed the novel dipeptide supramolecular hydrogel with self-assembly gelation enhanced fluorescence emission. Tetraphenylethene (TPE) is almost non-emissive when molecularly dissolved in solution but turns to be highly fluorescent in aggregate states. The hydrogelator was constructed by using the TPE as the hydrophobic part and four different dipeptide (Gly-Gly、 Ser-Ser、 Asp-Asp and Tyr-Asp) as the hydrophilic component. We investigated these amphiphilic low-moleculars weight of the gelation pH value, performance of rheology, morphology and optical properties of the AIE characteristics. Each of the luminophore hydrogels has received different interesting results: TPE-GG is the minimum molecular weight of TPE-capped peptide forms the supramolecular hydrogel. TPE-SS is the minimum molecular weight of TPE-capped peptide forms the supramolecular hydrogel under neutral condition. TPE-DD could form the hydrogel under the acid condition(pH value= 4.3) and could be a pH sensor. TPE-YD can form the strongest hydrgel under the acid condition(pH value= 4.3) and also can form stable hydrgel under neutral condition. TPE-SS and TPE-YD can form hydrogel under neutral condition. These materials are potentially useful for develop 3D cell culture in the future. TPE-DD could change the emission properties under different pH values, which may be promising a biomaterial as an active element of biosensors.
40
Lee, Ying-Nung, and 李怡儂. "Aggregation of SARS-CoV membrane protein induced by heat." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/31279254307817598750.
Abstract:
碩士慈濟大學
分子生物及細胞生物研究所
92
Severe acute respiratory syndrome (SARS) is a new respiratory illness caused by the infection of a novel coronavirus called SARS-CoV. Previous studies in our laboratory found that SARS-CoV membrane protein could be easily detected using Western blotting in non-denaturing condition but not in regular denaturing condition. Using Western blotting analysis and in vitro transcription /translation system (isotope-labeled), the aggregated membrane protein with the thermal denaturation (different temperature or different boiling time) was detected in the stacking gel. Therefore, the thermal aggregation of SARS-CoV membrane protein results in the inefficiency in detecting the membrane proteins. The aggregated membrane protein could not be re-dissolved by different denaturants: 2%SDS, 6Murea, 1%Triton-X100 Furthermore, the hydrophobic regions with amino acid residues from 61 to 90, from 91 to 100, and from 136 to 170 are essential for the aggregation of membrane protein. The membrane mutant protein with deletion from a.a.91 to 100 could be aggregated with wild type membrane protein when induced by heat. These results indicate that aggregation of SARS-CoV membrane protein induced by heat is through extensive interaction in hydrophobic domains. Therefore, if SARS-Cov membrane protein needs to be analyzed using SDS-PAGE, regular boiling treatment should be avoiding. Thermal aggregation of SARS-CoV membrane protein may be also responsible for the inactivation of this virus by heat. Thermal aggregation of SARS-CoV membrane protein also provides a model to study the protein aggregation.
41
Lin, Ya-Lin, and 林雅琳. "Platelet Aggregation Induced by Serotype Polysaccharide from Streptococcus mutans." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/15726071971429304067.
Abstract:
碩士國立臺灣大學
微生物學研究所
90
Abstract Infective endocarditis is characterized by the formation of vegetation, which is composed mainly of fibrin-platelet matrix, on damaged heart valves. Many bacterial proteins along with bacteria are able to activate platelets, and therefore play a crucial role in the pathogenesis because local activation of platelets contributes to the formation of vegetation. Using platelet aggregometry, we demonstrated in this study that Streptococcus mutans could aggregate platelets in rabbit platelet-rich plasma preparation in an irreversible and saturation manner. Both the heat sensitive and resistant bacterial components were responsible for the aggregation. However, their ability to aggregate platelets as well as the effects of heat inactivation were variable among different strains. Heat-stable serotype specific polysaccharide, which is composed of glucose-rhamnose polymers, is one of the major components responsible for platelet aggregation. The mutant strain Xc24R, defective in the synthesis of rhamnose backbone, was less effective in inducing aggregation compared to the wild type strain Xc and the other mutant Xc31, which is defective in the formation of glucose sidechain. In addition, polysaccharide extract from Xc and other laboratory strains, but not from Xc24R, weak in induced platelet aggregation. Whole bacteria or partially purified polysaccharide could not induce platelet aggregation in the absence of plasma, although polysaccharide could adhere directly to rabbit platelet and induce shape change. Absorption of plasma components by Xc strain could induce platelet aggregation, whereas absorption with Xc24R mutant strain failed to induce aggregation. Analysis by flow cytometry showed that S. mutans polysaccharide bind not only to rabbit platelets but also to human platelets. These results suggest that S. mutans could bind directly to platelets through its serotype specific polysaccharide. In the presence of plasma, other bacterial products might aggregate platelets directly or indirectly through binding of plasma components.
42
Huang, Pai-Ching, and 黃百慶. "Dexmedetomidine Enhances Adenosine Diphosphate-Induced Platelet Aggregation and Activation." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/77082214881544956058.
Abstract:
碩士中國醫藥大學
臨床醫學研究所碩士班
100
As an integral part in hemostasis, platelet has also been proved to play an important role in inflammation. Platelet activation was the very first step to participate in either hemostasis or inflammation. Many factors or molecules have been demonstrated as platelet stimulants. More and more platelet receptors were then discovered as well. The complicated networks of these receptor functions were composed of several distinct pathways. We could measure the different chemical products or physical phenomenons and thereby study the possible pathways in which were involved. In Taiwan, Precedex (dexmedetomidine) was used, as a sedative agent with analgesic effect, more and more frequently in ICU and operating room. In this study, we were the first to described that dexmedetomidine might have pro-aggregatory effect on platelet in vitro. We used several indicators of platelet activation, such as platelet aggregation, P-selectin, platelet-leukocyte aggregate, [Ca2+]i, and ATP, to measure the effect of dexmedetomidine on ADP-induced platelet aggregation and activation. Moreover, we used alpha antagonists to prove the above effect was through the activation of alpha-2 receptor on platelets. Then we compared the platelet counts before and after use of dexmedetomidine on ICU patients to preliminarily find out it’s possible effects in vivo. In this series of experiments, we have proved that dexmedetomidine could enhance ADP-induced platelet activation and aggregation through alpha-2 receptor in vitro. We should be cautious about prescribing dexmedetomidine for the patients with high risk of thromboembolism or inflammatory diseases.
43
Hsieh, Meng-Chieh, and 謝孟潔. "Aggregation Induced Photodynamic Therapy Enhancement of Binary Photosensitizers system." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/08756709360896622089.
Abstract:
碩士國立中興大學
生醫工程研究所
100
For the purpose to enhance the efficiency of PDT (photodynamic therapy) and extend its application; the binary system complexes were designed and synthesized with conjugating a chromophore (3, 6-bis-(1-methyl-4-vinyl- pyridinium) carbazole diiodide, BMVC) to mono-, bis- and trishydroxyl photosensitizers, respectively. BMVC plays the role of cancer cells recognizer; AIEE (aggregation-induced emission enhancement) generator and FRET (Fluorescence Resonance Energy Transfer) donor. The self assembling properties of these binary conjugates result in different degrees of AIEE and then achieve the formations of FONs (fluorescent organic nanoparticles), which present efficient FRET and singlet oxygen generations. Biologically, FONs-photosensitizers from these compounds were much more phototoxicities to cancer cell than to normal cell without significant dark toxicity. This improved photodynamic activity might be due to the aggregation of compounds in the cell that form FONs which can promote PDT and are observed in cancer cell but not normal cell. In the second stage, we screened the compounds which offered better PDT efficiency from the SAR (structure activity relationship) and modified the molecular structure furtherly. We embedded the metal ion such as Zn2+ and Pt2+ in the center of porphyrin to affect the activation area of FRET and prolong the triplet state life time. Then measured the singlet oxygen generation rate ability by using 1, 3-diphenylisobenzofuran (DPBF), to make sure the metallo binary system has better PDT efficiency than metal-free binary conjugates.
44
Chen, Jyun-Wei, and 陳俊瑋. "Novel Aggregation-Induced Emission Fluorophores Applied on Cellular Studies." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/88facz.
Abstract:
博士國立中興大學
化學工程學系所
106
In this study, we focused on developing the newly organic molecules on the therapy and diagnosis of cancers. In the experiments, we synthesized some simple fluorescent organic molecules and enhanced their performances in the cells by the unique properties of Aggregation-Induced Emission (AIE). First, we synthesized an asymmetric 1, 6-disubstituted naphthalene (NV-12P), which can generate particular reactive oxygen species to undergo type I photodynamic therapy under irradiation. Furthermore, this compound can specifically localize in mitochondria in cancer cells to exhibit selective dark cytotoxicity, and exhibit efficient photodamage in cancer cells due to intracellular bright spots. Results suggested that this compound can be a potential dual-toxic efficacy molecule. Additionally, a water-soluble pH sensor ADA was designed and synthesized based on the molecular design of photo-induced electron transfer (PET) and intramolecular charge transfer (ICT). The fluorescent emission response against a pH value located in the range of 3~6, which is suitable to label intracellular pH dependent microenvironments. Finally, we not only used ADA to identify intracellular pH gradients between different cell lines, but also developed ADA as a fluorescent molecule that labeled normal cells by the unique fluorescence intensity of ADA in normal cells, making it effective as the control group at the time of cancer diagnosis.
45
Mandal, Kuheli. "Fluorescent Bioimaging Probe from Aggregation Induced Emission Active Molecule." Thesis, 2019. http://hdl.handle.net/10821/8341.
46
LIN, YUN-RU, and 林韻茹. "Investigation of Aggregation-Induced-Emission Behavior for Tetraphenylethylene-Based Polymer." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/j97wv6.
Abstract:
碩士逢甲大學
化學工程學系
105
In this study, we successfully synthesized a small molecules with tetraphenylethylene as the basic structure and the correspounding polymer. Two methods were tested when small molecules was synthesized. The product synthesized by McMurry reaction found to be a good method for the synthesis of small molecules. The molecules were polymerized to obtain the corresponding macromolecule materials. Then, the absorption spectra, fluorescence spectra, aggregation-induced emission effect and quantum yield were measured, respectively. The results showed that the absorption and fluorescence peaks of polymer were bathochromic shifted as conjugation chain was increased. The size of the polymer gradually increased with the increasing of the water fraction of solvent and begins to decrease after the water fraction reach 70% water percentage. The result agrees with the fact that the smaller size particle favor closer packing of polymer molecules and showed brighter fluorescence. In the polymer systems, the intramolecular rotations of the phenyl rotors are already partly restricted at molecular level due to the steric effect of polymer chains. Finally, the thermal stability was measured, the Td was 380℃, and the polymer showed nice thermal stability.
47
Chang, Jean-Yun, and 張景雲. "TGF-beta induced aggregation of trafficking protein TRAPPC6A and apoptosis." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/77836481218037923263.
Abstract:
碩士國立成功大學
分子醫學研究所
97
Protein aggregation is central to the development of neurodegeneration such as Alzheimer’s disease. Here, we isolated a TGF-beta1-induced trafficking protein particle complex 6A, designated TPC6Adelta, which binds tumor suppressor WOX1 (also named WWOX or FOR). Compared to the wild type (22 kDa), TPC6Adelta has an N-terminal truncation of amino acid 29-42. TPC6A is a component of transport protein particle (TRAPP) complex in vesicle trafficking from ER to the Golgi complex in yeast. In contrast, mammalian TPC6A mainly localizes in the nuclei and at the perinuclear area. By co-immunoprecipitation, endogenous WOX1 was shown to interact with TPC6A. By FRET analysis, TPC6Adelta physically bound to the C-terminal tail (D3 domain) and ADH/SDR domain of WOX1. Prolonged stimulation of cells with TGF-beta1 reduced the binding of TPC6Adelta and WOX1, which ultimately resulted in TPC6Adelta aggregation. Notably, plaque-like TPC6A aggregates were found in the hippocami of patients with Alzheimer’s disease (AD) and transgenic AD mice model. Most importantly, TPC6A aggregates (> 0.2 micrometer in diameter) were more abundant in the younger nondemented human populations (60±13.3 years old, n=11) than in the older AD patients (81±9.7 years old, n=27), suggesting TPC6A is a likely marker for AD development. Time-lapse microscopy revealed that TGF-beta induced aggregation of intracellular TPC6Adelta. The aggregation may lead to Abeta superproduction and neuronal death. WOX1 and TPC6Adelta nullified each other in causing apoptosis, implying that WOX1 prevents aggregation of TPC6Adelta in cells. Together, here we discovered a novel mechanism for the pathogenesis of AD, which involves TGF-beta-induced TPC6A aggregation. Mechanistically, TGF-beta induces dissociation TPC6A from WOX1, followed by TPC6A aggregation, Abeta deposition and plaque formation.
48
Przybycien, Todd Michael. "Structure, Function and Aggregation Kinetics in Salt-Induced Protein Precipitation." Thesis, 1989. https://thesis.library.caltech.edu/686/3/przybycien-tm_1989.pdf.
Abstract:
Salt-induced precipitation is a biological separation technique that exposes proteins to unnatural environments. Macromolecular-scale issues of activity, structure, and aggregation have been addressed as a function of governing parameters.
The effects of salt type and concentration on protein solubility and recoverable activity were studied using α-chymotrypsin (αCT) as a model protein and five salts spanning the lyotropic series. Unaccounted for salt-protein interactions and changes in protein physical properties were the likely source of discrepencies between the experimental and theoretical solubility behavior. Active protein recovery was a function of salt type, but not concentration. A salting-out performance parameter was identified; an optimum salt may exist for a particular protein.
αCT precipitates from the solubility-activity study were examined for perturbations in secondary structure via Raman spectroscopy and in active site tertiary structure via electron paramagnetic resonance spectroscopy. NaBr, KBr, and KSCN-induced precipitates had increased β-sheet and decreased α-helix contents; these changes were correlated with active protein yields. Spectra of spin-labelled precipitates indicated that the active site remains intact. Molecular modelling was used to estimate changes in the dipole moment and hydrophobic surface area for the altered precipitates. A general mechanism for the precipitation of globular proteins was proposed.
The generality of secondary structure changes was explored for twelve different proteins via Raman spectroscopy. KSCN-induced precipitates exhibited increased β-sheet and decreased α-helix contents; structural changes for Na₂SO₄-induced precipitates were less significant. The β-sheet increase may occur at the expense of α-helix segments. β-sheet increases were correlated with the fraction of charged residues and the surface area of the native protein. α-helix decreases were correlated with the dipole moment and helical content of the native protein.
The effects of temperature, protein concentration, salt type, and salt concentration on αCT aggregation kinetics were studied. Stopped-flow turbidimetry indicated that temperature and salt concentration effects are exerted through changes in protein solubility. Protein concentration effects are well-described by Smoluchowski's collision equation. The aggregation of partially inhibited αCT demonstrated poisoning behavior. Solute particle radius distributions determined by dynamic laser light scattering indicated that aggregation denends on the supersaturation. A detailed population balance model, accounting for specific and nonspecific quaternary interactions, was developed.
49
(9748970), Hengming Qiu. "DNA Signal Induced Fusion And Aggregation Behaviors of Synthetic Cells." Thesis, 2020.
Abstract:
This thesis investigates the use of engineered DNA to program fusion and aggregation behaviors of artificial cells, mimicking biological cells and their important functions. To achieve this goal, we construct synthetic cells from engineered lipids and DNA to recognize and process intercellular signals.Cell fusion is regulated by snap receptor (SNARE) proteins in mammalian cells. The zippering of SNARE proteins exerts forces to the adjacent cell membrane and induces membrane fusion. The hybridization of membrane anchored DNA can induce fusion in a similar way. The advantage of using DNA as a fusion signal is that oligonucleotides are much easier to engineer and control. In this study, we construct two types of small vesicles decorated with DNA oligonucleotides and demonstrate their fusion using programmable DNA base-pairing. Fluorescent probes are used to measure fusion events. The experiment advances our understanding of the dynamic vesicle fusion behavior.
Cell aggregation is a complex behavior that is closely associated to the differentiation, migration, and viability of biological cells. An effort to create synthetic analogs could lead to considerable advances in cell physiology and biophysics. Rendering and modulating such a dynamic artificial cell system require mechanisms for receiving, transducing, and transmitting intercellular signals, yet effective tools are limited at present. Here we construct synthetic cells and show their programmable aggregation behaviors using DNA oligonucleotides as a signaling molecule. The synthetic cells have transmembrane DNA origami that are used to recognize and process intercellular signals. We demonstrate that multiple small vesicles aggregate onto a giant vesicle after a transduction of external DNA signals by an intracellular enzyme, and that the small vesicles dissociate when receiving ‘release’ signals.
We envision that this thesis will provide a new platform for building programmable synthetic protocells capable of chemical communication and coordination.
50
CHEN, PIN-RUEI, and 陳品叡. "Aggregation-induced emission in tetrasubstituted tetraphenylethene derivatives: synthesis and characterization." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/kj8s8y.
Abstract:
碩士逢甲大學
化學工程學系
107
Luminescent materials with aggregation-induced emission (AIE) properties have attracted many people's interest in recent years due to their application in, optoelectronic components, fluorescent probes, chemical sensor, and biosensor. Tetraphenylethene (TPE) is a compound that often used to investigate luminescence properties with significant AIE. In this study, TPE derivatives 9, 14, 15, 16, 18a-d with tetra-substituted structure were successfully synthesized, and their absorption spectra, fluorescence spectra, aggregation-induced luminescence, liquid fluorescence quantum yield and electrochemical properties were studied. Based on the red-shift of absorption and fluorescence spectra for compounds 14, and 15, the conjugation growth was observed. In the aggregation-induced emission test, it was found that the fluorescence intensity increased with decrease of the solution solubility, and red-shift of fluorescence occurred. The compound 14, with Tetramethyl silane (TMS) substituents, showed the highest fluorescence quantum yield (56.7%). Moreover, different alkyl chains led to different fluorescence quantum yield. The oxidation potential of the compounds was determined by cyclic voltammetry and the energy of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) was estimated. The thermal decomposition temperatures of the compounds were above 300oC revealing good thermal stability.