Betalaínas são pigmentos nitrogenados de cor vermelha-violeta ou amarela encontrados em um número restrito de espécies de plantas e fungos. Esta Tese de Doutorado apresenta o desenvolvimento de um derivado betalaínico com sistema π estendido chamado de BeetBlue, a caracterização de suas propriedades estruturais, redox e espectroscópicas e o estudo do seu comportamento na presença de outras espécies químicas. Este corante foi semissintetizado a partir do acoplamento entre 2,4-dimetilpirrol e ácido betalâmico extraído de suco de beterraba hidrolisado. Embora o sistema diazapolimetínico com nove grupos metilênicos da BeetBlue seja análogo ao da indocianina verde, um corante fluorescente de grande interesse aplicado, BeetBlue é azul-violeta e pouco fluorescente em soluções de solventes moleculares. A diminuição da polaridade ou aumento da viscosidade do meio aumentam o seu rendimento quântico de fluorescência em até três ordens de grandeza e a complexação com lantanídeos em meio aquoso muda a sua cor de azul para laranja. BeetBlue é sensível à hidrólise catalisada por base e à oxidação, o que oferece novas oportunidades para o seu uso no desenvolvimento de métodos analíticos. Este corante não é citotóxico para células de epitélio de retina e não afetou o desenvolvimento de embriões e larvas de peixe-zebra. BeetBlue é o protótipo de uma nova classe de pigmentos polimetínicos quirais solúveis em água, as quasibetalaínas, que apresentam grande potencial de aplicação como corantes seguros para o meio ambiente e saúde animal. / Betalains are nitrogen-containing pigments of red-violet or yellow color found in a restricted number of species of plants and fungi. This Doctoral Thesis presents the development of a betalain derivative with an extended π system called BeetBlue, the characterization of its structural, redox and spectroscopic properties and the study of its behavior in the presence of other chemical species. This dye was semi-synthesized from the coupling of 2,4-dimethylpyrrole and betalamic acid extracted from hydrolyzed beet juice. Although the diazapolimethyne system with nine methylene groups of BeetBlue is analogous to that of indocyanine green, a fluorescent dye of great interest, BeetBlue is blue-violet and poorly fluorescent in solutions of molecular solvents. The decrease in polarity or increase in the viscosity of the medium increases its fluorescence quantum yield by up to three orders of magnitude, and the complexation with lanthanides in aqueous medium changes its color from blue to orange. BeetBlue is sensitive to basecatalyzed hydrolysis and oxidation, which offers new opportunities for its use in the development of analytical methods. This dye is non-cytotoxic to retinal epithelial cells and did not affect the development of zebrafish embryos and larvae. BeetBlue is the prototype of a new class of water-soluble chiral polymethynic pigments, the quasibetalains, which present great potential for application as safe dyes for the environment and animal health.

Lam Sio Kuan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 111-116). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Nós estudamos experimentalmente e teoricamente Efeitos Transientes em conjugação de Fase por Mistura Degenerada de Quatro ondas em cristais dopados com Cr POT. 3+. Estudamos os efeitos transientes na conjugação de fase em Al IND 2 O IND. 2 : Cr POT. 3+ (Rubi) e GdAl O IND. 3 Cr POT. 3+ (aluminato de gadolíneo) com um laser de Ar POT. + (em =514,5nm). Um novo modelo teórico é apresentado que explica razoavelmente os resultados experimentais cuja compreensão anterior pela literatura era devido somente pela parte absortiva do índice de refração[12] pois em cristais dopados com Cr POT. 3+ (Al IND. 2 O IND. 3: Cr POT. 3+ e GdAl O IND. 3 : Cr POT. 3+ a parte dispersiva do índice de refração não-linear n IND. 2 é pelo menos uma ordem de grandeza maior que a parte absortiva [15,28]. / We have studied experimentally and theoretically Transient Effects in Degenerate Four-Wave Mixing by Phase Conjugation in ion-doped crystals with Cf3+. We have studied transient effects in phase conjugation in Al2O3:Cf3+ (Ruby) and GdAlO3:Cr3+ Gadolinium Aluminate) with an Argon laser (at =514.5nm). A new theoretical model is presented that reasonably explains our experimental results whose understanding in previous papers was due to the imaginary part of the refraction index [12] because in crystals doped with cr3+ (Al2O3:Cr3+ and GdAIO3:Cr3+) the real part of the nonlinear refraction index n2 is at least one order of magnitude greater than the imaginary part [15,28].

For packet-switched metro networks, one of the key functional blocks is the transmission, extraction and update of in-band packet control information, which is commonly known as packet label swapping. The use of phase modulation to carry the control information can facilitate easy swapping process. By combining phase modulated label with intensity modulated optical packets in non-overlapping manners, we demonstrated that optical packet label swapping using differential phase-shift keyed labels could be achieved without any sacrifices in packet signal quality. / In packet-switched optical networks, packets are routed using IP-based distributed routing algorithms. Inconsistencies in routing information among routing nodes may result in routing loop formation in the network and may cause severe impact on the network performance. We proposed a novel packet routing loop mitigation scheme based on the principle of packet 'time-to-live' value countdown. This scheme enables loop mitigation to be performed asynchronously in optical domain, causing little packet processing delay. Two implementations were proposed. One was based on differential optical phase shift keying and the other was based on self-phase modulation in semiconductor optical amplifier. / The continuous increase in Internet-bound data traffic in recent years has placed higher requirement on network bandwidth and flexibility. In view of this, packet-switched metro networks and broadband passive optical access networks have emerged as the promising network solutions in the near future. The focus of this thesis is on the improvement of functionality and reliability as well as the reduction of system complexity in optical metro area and access networks with the use of optical phase modulation techniques. In access network, constant-intensity optical phase modulation formats were studied for their applications in wavelength-division-multiplexed passive optical networks with centralized light source. Using them as downstream modulation formats, the downstream optical carrier can be utilized to carry upstream intensity-modulated data. It can greatly simplify upstream transmission and facilitate network management. Experimental and numerical analyses shows promising upstream re-modulation performance with a simple optical network unit (ONU) configuration. / Hung Wai. / Adviser: Lian-Kuan Chen. / Source: Dissertation Abstracts International, Volume: 70-09, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 130-135). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

by Tong Wai Yin Alex. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaf 55). / by Tong Wai Yin Alex. / Acknowledgement / Biographical Sketch / Abstract / Table of contents / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Nonlinear Optics in dye-doped solid --- p.4 / Chapter 2.1 --- Nonlinear Optics --- p.4 / Chapter 2.2 --- Photophysics of dye molecules --- p.6 / Chapter 2.3 --- Nonlinear effect in dye-doped solid --- p.8 / Chapter Chapter 3 --- Sol-Gel Silica --- p.11 / Chapter 3.1 --- The formation of dye-doped sol-gel silica --- p.11 / Chapter 3.2 --- The physical properties --- p.15 / Chapter 3.3 --- The optical properties --- p.16 / Chapter Chapter 4 --- Saturation Absorption --- p.18 / Chapter 4.1 --- Saturation Absorption in Fluorescein 548 dye-doped solid --- p.18 / Chapter 4.2 --- Experimental Details --- p.19 / Chapter 4.3 --- Results and Discussion --- p.19 / Chapter 4.4 --- Conclusion --- p.30 / Chapter Chapter 5 --- Optical Phase Conjucation --- p.31 / Chapter 5.1 --- OPC Theory --- p.31 / Chapter 5.11 --- The Distortion Correction Theorem --- p.32 / Chapter 5.12 --- The Proof of the Distortion Theorem --- p.32 / Chapter 5.13 --- The generation of Phase Conjucate Waves --- p.34 / Chapter 5.2 --- Degenerate Four Wave Mixing --- p.35 / Chapter 5.21 --- Geometries of DFWM --- p.35 / Chapter 5.22 --- DFWM Theory --- p.37 / Chapter 5.23 --- DFWM in Absorbing Media --- p.40 / Chapter 5.3 --- Experimental Details --- p.44 / Chapter 5.4 --- Results and Discussion --- p.46 / Chapter 5.5 --- Conclusion --- p.53 / Chapter Chapter 6 --- Conclusion and Suggestions for future work --- p.54 / Reference

A la suite de nombreuses illustrations et validations au niveau fondamental, la chimie de molécules carbo-mères s'est récemment orientée vers des cibles fonctionnelles en termes de perspectives d'applications (" carbo-matériaux " moléculaires). C'est ainsi que de telles molécules expansées en carbone ont récemment montré des propriétés remarquables dans les domaines de la conductivité sur molécule unique (SMC) ou de l'absorption à deux photons (TPA). La considération de cibles de types fondamentalement nouveaux " reste cependant nécessaire en préliminaire à l'étude de propriétés nouvelles aussi. Le travail décrit dans ce manuscrit présente essentiellement les résultats concernant la synthèse de carbo-quinoïdes et de carbo-benzénoïdes, deux types de structures carbo-mères qui n'avaient jamais été envisagées expérimentalement auparavant. Le premier chapitre est un résumé bibliographique décrivant notamment la synthèse et les propriétés de molécules carbo-mères aromatiques, et plus généralement hautement pi-conjuguées (carbo-benzènes, carbo-cyclohexadiènes, carbo-oligoacétylènes...) Le second chapitre porte sur l'étude complète des trois régioisomères, " ortho ", " para ", et " meta " du tétraphényl-carbo-benzène, dont les deux premiers représentants avaient été partiellement décrits. Le troisième chapitre décrit la synthèse et l'étude du premier exemple de carbo-quinoïde, ainsi que sa transformation rédox réversible en carbo-benzènes, illustrant ainsi la " pro-aromaticité redox " des carbo-quinoïdes vis-à-vis de leurs analogues oxydés carbo-benzènes. Le quatrième et dernier chapitre est consacré à la synthèse et l'étude d'un carbo-benzénoïde, le carbo-naphtalène, pouvant être considéré comme le plus petit fragment polycyclique condensé d'alpha-graphyne, un matériau largement étudié au niveau théorique mais encore inconnu expérimentalement à ce jour. Les propriétés physico-chimiques et spectroscopiques de carbo-naphtalène sont comparées à celle du carbo-benzène monocyclique correspondant, dont la synthèse est aussi détaillée. / Following numerous illustrations and validations at the fundamental level, the chemistry of carbo-meric molecules was recently directed towards functional targets in terms of application prospects (molecular "carbo-materials'). Such carbon-expanded molecules have indeed recently been shown to exhibit remarkable properties in the areas of single molecule conductivity (SMC) or two-photon absorption efficiency (TPA). The consideration of target of fundamentally "new types" remains necessary in view of the study of new properties as well. The work described in this manuscript focus mainly on results concerning the synthesis of carbo-quinoids and carbo-benzenoids, two types of carbo-meric structures that had not been considered hitherto. The first chapter is a bibliographic summary describing the synthesis and properties of carbo-meric molecules, either aromatic or, more generally, highly pi-conjugated (carbo-benzenes, carbo-cyclohexadienes, carbo-oligoacetylenes...) The second chapter focuses on the complete study of the three regioisomers, "ortho", "para" and "meta" of tetraphenyl-carbo-benzene, the first two representatives having been partly described previously. The third chapter describes the synthesis and study of the first example of carbo-quinoid and its reversible redox transformation to carbo-benzenes, illustrating the "redox pro-aromaticity" of carbo-quinoid with respect to their oxidized carbo-benzenic analogues. The fourth and final chapter is devoted to the synthesis and study of a carbo-benzenoid, carbo-naphthalene, which can be regarded as the smallest condensed polycyclic fragment of alpha-graphyne, a material widely studied at the theoretical level but remaining unknown experimentally to date. The physicochemical and spectroscopic properties of carbo-naphthalene are compared to that of the corresponding monocyclic carbo-benzene, the synthesis of which is also detailed.

Nós estudamos experimentalmente e teoricamente Efeitos Transientes em conjugação de Fase por Mistura Degenerada de Quatro ondas em cristais dopados com Cr POT. 3+. Estudamos os efeitos transientes na conjugação de fase em Al IND 2 O IND. 2 : Cr POT. 3+ (Rubi) e GdAl O IND. 3 Cr POT. 3+ (aluminato de gadolíneo) com um laser de Ar POT. + (em =514,5nm). Um novo modelo teórico é apresentado que explica razoavelmente os resultados experimentais cuja compreensão anterior pela literatura era devido somente pela parte absortiva do índice de refração[12] pois em cristais dopados com Cr POT. 3+ (Al IND. 2 O IND. 3: Cr POT. 3+ e GdAl O IND. 3 : Cr POT. 3+ a parte dispersiva do índice de refração não-linear n IND. 2 é pelo menos uma ordem de grandeza maior que a parte absortiva [15,28]. / We have studied experimentally and theoretically Transient Effects in Degenerate Four-Wave Mixing by Phase Conjugation in ion-doped crystals with Cf3+. We have studied transient effects in phase conjugation in Al2O3:Cf3+ (Ruby) and GdAlO3:Cr3+ Gadolinium Aluminate) with an Argon laser (at =514.5nm). A new theoretical model is presented that reasonably explains our experimental results whose understanding in previous papers was due to the imaginary part of the refraction index [12] because in crystals doped with cr3+ (Al2O3:Cr3+ and GdAIO3:Cr3+) the real part of the nonlinear refraction index n2 is at least one order of magnitude greater than the imaginary part [15,28].

This study was conducted to examine the rate of contamination and molecular characteristics of enteric bacteria isolated from a selection of food sources in Vietnam. One hundred and eighty raw food samples were tested and 60.8% of meat and 18.0% of shellfish samples were found to be contaminated with Salmonella spp. which belonged to variety of serogroups and serotypes. More than 90% of all food sources contained Escherichia coli and 32% of 50 shellfish samples were contaminated with Vibrio parahaemolyticus. PFGE was used to determine the degree of relatedness of Salmonella spp. There were 33 distinct PFGE patterns from 51 Salmonella spp. isolates tested, indicating that PFGE could be used as an alternative method for serotyping for use in epidemiology of Salmonella spp. Susceptibility of the isolates to 15 antimicrobial agents was investigated. Moderate to high frequencies of resistance to antibiotics were observed in Salmonella spp. and E. coli isolates and multi-resistance, defined as resistance to at least 4 antibiotics, was observed. All of the V. parahaemolyticus isolates were resistant to ampicillin/amoxicillin but not to other antibiotics. Betalactam TEM gene and tetracycline resistance tetA, tetB genes were widely distributed in both E. coli and Salmonella spp. isolates. Other resistance genes, including sulI, cmlA, aadA, aphA1, dhfrV, and aac(3)-IV were also present at high to moderate levels. Identification and characterisation of the mobile genetic elements, including identification of class 1 integrons and plasmids were carried out for multi-resistance isolates. The integrons harboured varying gene cassettes, including aadA1, aadA2, aadA5, aacA4, dhfrXII, drfA1 and dhfrA17, blaPSE1 and catB3. Thirty-five percent of Salmonella spp. isolates and 76% of E. coli isolates harboured plasmids of more than 95 kb. Transfer of resistance phenotypes between the isolates via conjugation and phage transduction was also demonstrated. Salmonella genomic island 1 (SGI1), a 43-kb genomic region contains a 13-kb antibiotic resistance gene cluster, has been identified in an isolate of S. Albany from chicken. The presence of Salmonella spp. virulence genes was investigated to examine the pathogenicity potential of the isolates. The invA gene was present in all Salmonella spp. isolates and the plasmid virulence gene spvC was detected in one S. Typhimurium isolate only, on a 95 kb virulence plasmid. Invasion assays performed in vitro demonstrated that all Salmonella isolates were capable of invading human intestine INT407 cells. In addition, the investigation for the presence of 58 selected virulence genes showed that all the tested isolates contained at least one virulence gene and there were 16 genes which are associated with different pathotypes detected. The data obtained in this study indicates that raw food in Vietnam is a potential reservoirs for many pathogenic organisms, and confirms the role of food animals as a reservoir of multidrug resistant E. coli and Salmonella spp.

The conjugation of a small organic molecule to synthetic polypeptides from a designed set has been shown to give rise to binders with high affinity and selectivity for the phosphorylated model proteins α-casein and β-casein but not for ovoalbumin. The small organic molecule that was used for this purpose is comprised of two di-(2-picolyl)amine groups assembled on a dimethylphenyl scaffold, and is capable of complexing two Zn2+ ions to form chelates that bind the phosphate ion. The designed polypeptides used for binder construction have no precedence in nature and do not show any prior selectivity favouring any single protein. The polypeptide conjugate binders showed high affinity towards the model protein α-casein, the binder molecule 4C15L8-PP1 bound α-casein with a dissociation constant KD of 17 nM, although the di-(2-picolyl) amine based chelate in the presence of Zn2+ bound phosphate ion with dissociation constants in the low mM range. The observed affinity is due to interactions between the Zn2+ chelate and the phosphate groups of α-casein and also to interactions between the polypeptide scaffold and α-casein. The binder was found to selectively extract α-casein from buffer, bovine milk and human serum spiked with α-casein. The flexible construction of the binder permits for flexible modifications like attachment of fluorophores for titrations and quantifications. The binders were shown to efficiently capture α-casein from human serum when immobilized on solid support in a continuous flow system and to release the captured α-casein upon a simple change of pH using 0.1% acqueous trifluoroacetica acid. The developed technology brings new opportunities in investigating posttranslational phosphorylation events that are involved in signaling cascades and triggering many biologically relevant functions. A new chemical linker technology has also been developed for the purpose of conjugating biomolecules taking advantage of amino groups for the conjugation. By combining two esters with different reactivities, separated by an aliphatic chain, a molecular tool was developed that allows for controlled conjugation of biomolecules. The two esters react at different rates and can therefore be separated and allowed to react under different conditions in each step, thereby allowing for selective linkage formation between the subunits. The size of the spacer can be varied by selecting the appropriate dicarboxylic acid. The developed technology was shown to provide specificity in heteroconjugate formation in the assembly of a variety of heteroconjugates where polypeptides were combined with other peptides, carbohydrates and proteins.

Over the past decade, solid-state nanopores have emerged as a versatile tool for the detection and characterization of single molecules, showing great promise in the field of personalized medicine as diagnostic and genotyping platforms. While solid-state nanopores offer increased durability and functionality over a wider range of experimental conditions compared to their biological counterparts, reliable fabrication of low-noise solid-state nanopores remains a challenge. In this thesis, a methodology for treating nanopores using high electric fields in an automated fashion by applying short (0.1-2 s) pulses of 6-10 V is presented which drastically improves the yield of nanopores that can be used for molecular recognition studies. In particular, this technique allows for sub-nanometer control over nanopore size under experimental conditions, facilitates complete wetting of nanopores, reduces noise by up to three orders of magnitude and rejuvenates used pores for further experimentation. This improvement in fabrication yield (over 90%) ultimately makes nanopore-based sensing more efficient, cost-effective and accessible. Tuning size using high electric fields facilitates nanopore fabrication and improves functionality for single-molecule experiments. Here, the use of nanopores for the detection of DNA-protein complexes is examined. As proof-of-concept, neutravidin bound to double-stranded DNA is used as a model complex. The creation of the DNA-neutravidin complex using polymerase chain reaction with biotinylated primers and subsequent purification and multiplex creation is discussed. Finally, an outlook for extending this scheme for the identification of proteins in a sample based on translocation signatures is presented which could be implemented in a portable lab-on-a-chip device for the rapid detection of disease biomarkers.