The development of new storage materials will facilitate the use of hydrogen as a major energy carrier in near future. In hydrogen economy, chemical hydrides such as NaBH4, KBH4, LiH, NaH have been tested as hydrogen storage materials for supplying hydrogen at ambient temperature. Among these chemical hydrides, sodium borohydride seems to be an ideal hydrogen storage material because it is stable under ordinary conditions and liberates hydrogen gas in a safe and controllable way in aqueous solutions. However, self hydrolysis of sodium borohydride is so slow that it requires a suitable catalyst. All of the prior catalysts tested for the hydrolysis of sodium borohydride are heterogeneous and, therefore, have limited activity because of the small surface area. Here, we report for the first time the employment of water dispersible metal(0) nanoclusters having a large portion of atoms on the surface as a catalyst for the hydrolysis of sodium borohydride. In-situ formation of nickel(0) nanoclusters and catalytic hydrolysis of sodium borohydride were performed in the same medium. Nickel(0) nanoclusters are prepared from the reduction of nickel(II) acetylacetonate by sodium borohydride in aqueous solution and stabilized with hydrogenphosphate anions. The nickel(0) nanoclusters were characterized by using XPS, Powder XRD, FT-IR, UV-Vis and NMR spectroscopic methods. The kinetics of the nickel(0) nanoclusters catalyzed hydrolysis of sodium borohydride was studied depending on the catalyst concentration, substrate concentration, stabilizing agent concentration and temperature. Tha kinetic study shows that the nickel(0) nanocluster-catalyzed hydrolysis of sodium borohydride is first order with respect to catalyst concentration and zero order with respect to substrate concentration The activation parameters of this reaction were also determined from the evaluation of the kinetic data. The hydrogenphosphate-stabilized nickel(0) nanoclusters provide a lower activation energy (Ea= 55 kJ/mol) than bulk nickel (Ea=73 kJ/mol) for the hydrolysis of sodium borohydride.

Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-10-26T15:25:30Z No. of bitstreams: 1 Dissertação - João Vitor Silva de Loureiro.pdf: 2409815 bytes, checksum: 3450dbc2ad4f05bc1bd2ccbd06e220a6 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-26T18:05:45Z (GMT) No. of bitstreams: 1 Dissertação - João Vitor Silva de Loureiro.pdf: 2409815 bytes, checksum: 3450dbc2ad4f05bc1bd2ccbd06e220a6 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-26T18:07:52Z (GMT) No. of bitstreams: 1 Dissertação - João Vitor Silva de Loureiro.pdf: 2409815 bytes, checksum: 3450dbc2ad4f05bc1bd2ccbd06e220a6 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-26T18:21:27Z (GMT) No. of bitstreams: 1 Dissertação - João Vitor Silva de Loureiro.pdf: 2409815 bytes, checksum: 3450dbc2ad4f05bc1bd2ccbd06e220a6 (MD5) / Made available in DSpace on 2015-10-26T18:21:27Z (GMT). No. of bitstreams: 1 Dissertação - João Vitor Silva de Loureiro.pdf: 2409815 bytes, checksum: 3450dbc2ad4f05bc1bd2ccbd06e220a6 (MD5) Previous issue date: 2015-05-15 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The formation of Terra Preta (TPI) intrigued many researchers, besides it has too many hypotheses, the most likely involves human activities, whose origin is related to the deposition of material remained of pre-Columbian populations. It resulted in soils rich in humic acid (HA) that are regarded as natural binders most widely distributed in nature, which greatly contributes to soil fertility. This study applied statistical methods of multivariate analyzes such as hierarchical cluster analysis (HCA), Principal Component Analysis (PCA), infrared spectra Fourier Transform (FT-IR) and ultraviolet-visible spectra (UV-Vis) AH ICC for eight sites in the Amazon region, and applied to spectra of X-ray diffraction (XRD) of soil same eight sites of the ICC. Statistical methods were applied using the R software that makes use of normalization of the data obtained from each spectrum to generate the results of PCA and HCA. Using r software tools, it was possible observe which functional groups and stretches contributed positively OH, C=O and C=C, to generate graphics of PCA and HCA extracted from the FT-IR spectra. As for the results of UV-Vis spectra it was not possible to observe that groups could contribute to generation of HCA and PCA. For the XRD spectra it was observed that the PC1 that kaolinite and illite were the most positive contribution to the graphics, the PC2 that in most of the contribution was quartz. Thus, the simple application of HCA and PCA in the spectra allowed to compare the eight sites and classifies them according to similarity of the spectra. / A formação da Terra Preta de Índio (TPI) intriga muitos pesquisadores, por mais que exista muitas hipóteses, a mais plausível envolve atividades antrópicas, cuja origem está relacionada à deposição de restos de materiais de populações précolombianas. O que resultou em solos ricos em ácidos húmicos (AH), que são consideradas ligantes naturais mais amplamente distribuídos na natureza, o que contribui bastante para a fertilidade do solo. Neste estudo foi aplicado os métodos estatísticos de análises multivariadas como Análise de Agrupamentos Hierárquicos (HCA) e Análise de Componentes Principais (PCA) de espectros de infravermelho com Transformada de Fourier (FT-IR) e espectros de ultravioleta-visível (UV-Vis) para AH de oito sítios de TPI da região amazônica, e aplicado para espectros de difração de raios x (DRX) de solos dos mesmos oito sítios de TPI. Os métodos estatísticos foram aplicados com software R, que faz uso de normalização dos dados obtidos de cada espectro para geração dos resultados de HCA e PCA. Com ajuda das ferramentas do software R foi possível observar grupos funcionas ou estiramentos contribuíram positivamente, O-H, C=O e C=C, para gerar os gráficos de HCA e PCA extraídos dos espectros FTIR. Já para os resultados obtidos dos espectros UV-Vis não foi possível observar que grupamentos poderiam contribuir para geração do HCA e PCA. Quanto aos espectros dos de DRX foi possível observar que que na PC1 a caulinita e a ilita foram as que mais contribuíram positivamente para os gráficos, quanto que na PC2 a maior parte da contribuição foi do quartzo. Dessa forma, a simples aplicação de HCA e PCA nos espectros permitiu comparar os oitos sítios e classifica-los segundo similaridades dos espectros.

An exceptionally important stress response of Pseudomonas putida strains to toxic chemicals is the induction of efflux pumps that extrude solvents, as well as other toxicants, into the surrounding medium. However, the bacterial tolerance mechanisms are still not fully understood, thus in this thesis metabolomic approaches were used to detect and identify metabolites involved in P. putida DOT-T1E tolerance to abiotic stresses, in particular focussing on the role of efflux pumps. To elucidate any metabolome alterations several strains of P. putida, including the wild type DOT-T1E, and the efflux pump knockouts DOT-T1E-PS28 and DOT-T1E-18, were challenged with different levels of propranolol. Fourier-transform infrared (FT-IR) spectroscopy, which provided a rapid, high-throughput metabolic fingerprint of P. putida strains, was used to investigate any phenotypic changes resulting from exposure to propranolol. FT-IR data illustrated phenotypic changes associated with the presence of propranolol within the cell that could be assigned to the bacterial protein components. To complement this phenotypic fingerprinting approach metabolic profiling on the same samples was performed using gas chromatography mass spectrometry (GC-MS) to identify metabolites of interest during growth of bacteria following this toxic perturbation with propranolol. GC-MS revealed significant changes in ornithine levels which can be directly linked to bacterial tolerance mechanisms, and alterations in the levels of several other metabolites which were also modified in response to propranolol exposure. Moreover, the effect of the organic solvent toluene was also investigated using the same approach. Examination of FT-IR data indicated that protein and fatty acids were the most affected components of P. putida strains due to the presence of toluene within the cell. Moreover, application of GC-MS allowed for the identification and quantification of several metabolites which were differentially produced or consumed in the presence of toluene. To investigate the role of efflux pumps in P. putida DOT-T1E, several analytical techniques were employed including Raman spectroscopy, gas and liquid chromatography to identify and quantify the level of propranolol or toluene in P. putida cells. These analyses showed that propranolol and toluene accumulated in the mutant P. putida DOT-T1E-18 (lacking the TtgABC pump) at higher levels in comparison with the levels found in the wild-type DOT-T1E and the mutant DOT-T1E-PS28 (lacking the TtgGHI pump), indicating the key role of efflux pumps in solvent tolerance. Furthermore, the effect of Mg2+ and Ca2+ on the stabilisation of the toluene tolerance of P. putida DOT-T1E strains was examined in order to elucidate whether divalent cations interact with efflux pumps or other resistant mechanisms to improve solvent tolerance. FT-IR analysis suggested that the influence of divalent cations on the stabilisation of the toluene tolerance could be due to the contribution of metal ions towards other tolerance mechanisms such as lipopolysaccharide (LPS) instead of enhancing the activity of efflux pumps. In conclusion, this thesis presents evidence that phenotypic fingerprinting and metabolic profiling approaches in combination with chemometric methods can generate valuable information on phenotypic responses occurring within microbial cultures subjected to abiotic stress.

Actuellement le criblage en vue de la recherche de nouveaux agents antitumoraux se base principalement sur la qualité cytotoxique d’une molécule. Le principal défaut de cette approche est qu’aucune sélection n’est faite sur le mode d’action du médicament. L’objectif de ce travail est la mise au point d’une méthode permettant un classement rapide et objectif du mode d’action de molécules à visée thérapeutique par spectroscopie infrarouge.<p>La spectroscopie infrarouge est une technique d’absorption de la lumière fournit la signature chimique d’un échantillon. L’excellente qualité du signal rend possible son utilisation comme outil discriminant. En outre, cette technique d’analyse se démarque des autres par son caractère non destructif et la rapidité d’acquisition des données. Elle se révèlerait donc une méthode de choix pour effectuer du criblage de molécules en vue de la recherche de nouveaux agents thérapeutiques.<p><p>Dans un premier temps nous avons voulu évaluer la possibilité d’utiliser la spectroscopie infrarouge pour isoler la signature spectrale du mode d’action induit par des concentrations sub-létales de ouabaïne, un composé de la famille des cardénolides, sur une lignée tumorale de prostate. Nous avons montré que cette signature évolue au cours du temps et peut-être corrélée aux données biologiques décrites dans la littérature. Nous avons également mis en évidence pour la première fois une modification de la composition lipidique de la cellule. Cette altération a été caractérisée au cours du temps par spectrométrie de masse.<p>Nous avons ensuite voulu définir les limites de la méthode. La littérature souligne la diversité des modes d’action que peut induire un agent thérapeutique selon sa concentration. Nous avons montré que cette diversité se reflète sur le spectre infrarouge de cellules tumorales traitées à la ouabaïne en distinguant au moins deux modes d’action distincts, dépendant de la concentration en ouabaïne. Par ailleurs, nous avons montré que la confluence pouvait modifier significativement le spectre infrarouge d’une cellule. Neanmoins cette signature est unique et orthogonale à celle induite par la ouabaïne.<p>Finalement, nous avons évalué le potentiel de la spectroscopie infrarouge à distinguer des modes d’action induits par des molécules à la structure chimique proche. Nous avons montré qu’il était possible de caractériser spécifiquement chacun des modes d’action. D’autre part nous avons mis en évidence que les modes d’action de molécules issues d’une même classe d’agent thérapeutique conduisaient à des signatures spectrales similaires. Cette partie du travail souligne la possibilité d’utilisation de la spectroscopie infrarouge pour un classement objectif, uniquement basé sur leur mode d’action d’agents thérapeutiques potentiels.<p> / Doctorat en Sciences agronomiques et ingénierie biologique / info:eu-repo/semantics/nonPublished

Master of Science / Department of Grain Science and Industry / David L. Wetzel / During germination, biochemical changes occur in the wheat kernel by stimulation of enzymes and hormones, and the seed reserves are mobilized. Infrared microspectroscopy and imaging enables a localized chemical inventory, upon germination, to study the process. Frozen sections of germinated wheat mounted onto BaF[subscript]2 were mapped to produce functional group images for comparison with corresponding sections of ungerminated kernels. Relative functional group populations in the scutellum and embryonic axis were assessed before and after germination. An average 23% reduction in lipid to protein ratio was observed in the scutellum based on the comparison of 53,733 spectra. As a result of the early germination process, lipid in the scutellum was depleted to provide energy for the growing embryo. Germination of the kernels while in the field before harvest due to high humidity is known as preharvest sprouting. Preharvest sprouting has detrimental effects on the end use quality of the wheat (sprout damage) and cause economic loses. Tolerance to preharvest sprouting is highly desirable. To assist breeding program, a nondestructive near-IR chemical imaging method has been developed to test new lines for resistance to preharvest sprouting. The higher sensitivity of subsurface chemical imaging, compared with visual detection, alpha amylase determination, or viscosity testing, permits germination detection at early stages. A near-IR chemical imaging system with an InGaAs focal plane array (FPA) detector in the 1100 nm-1700 nm range was used. Kernels from six different cultivars, including HRW and HWW wheat, were exposed to moist conditions for 6, 12, 24, 36, and 48 hours. Images of each 90 kernel group were examined; kernels exposed to moisture for 36 hours were compared with kernels treated for 3 hours as a control. Each kernel was classified as sprouted or not sprouted with the criteria of log 1/R intensity at select wavelengths or select factors of principle component analysis (PCA) treatment of reflectance intensity data. Imaging wavelength range was expanded beyond 1700 nm to 2400 nm with the use of InSb FPA. Study for the potential for unsupervised determination in nondestructive near-IR imaging with detection wavelengths 1200-2400 is ongoing. Some preliminary results presented are encouraging.

No description available.

The diploma thesis is confused to verify the applicability of selected physicochemical and spectroscopic methods for characterization of cyanobacteria, with special emphasis on possibilities of qualitative and quantitative analysis of polyhydroxyalkanoates (specifically polyhydroxybutyrate (PHB)) accumulated in cyanobacterial cells. The sample basis of the work was formed by cultures of cyanobacterial strains of Synechocystis sp. PCC 6803 and Synechocystis salina CCALA 192. The cultures were were cultivated in several ways to cover the widest possible range of physiological conditions and PHB contents, in particular using an autotrophic way of cultivation on shakers and multicultural culture method in a basic culture medium,and in media enriched with 2% salt (NaCl ) as well as mixotrophic culture media with different types of the carbon substrate. After few weeks of cultivation, cyanobacterial cultures were obtained and complexly analyzed by following techniques- cell suspensions were analyzed by flow cytometry and UV-VIS spectrometry (transmission and diffusion transmission mode), dry cell biomass was characterised by gas chromatography to obtain a exact amount of PHB, and then FT-IR spectrometry and thermogravimetric analysis. The work aimed to assess whether any of these methods can be a quick and affordable alternative to the determination of PHB content to the most commonly used method of gas chromatography, but also to assess what additional information about the physiological state of cyanobacterial cells can provide test methods. The highest correlation on PHB content was determined for the parameters determined by infrared spectroscopy, in which specific peaks from the characteristic wavelengths for polyhydroxybutyrate were important. Weak correlations on PHB content were achieved in thermogravimetric analysis and cytometry, using the hydrophobic fluorescent probe BODIPY 439/503, which bound to lipophilic parts of cells. In addition to the determination of PHB, it was possible to determine pigments present in cyanobacteria (such as chlorophyll, phycocyanin and carotenoids) by flow cytometry and UV-VIS diffusion transmission spectrometry. In the end, results from all used techniques were compared by PCA analysis to determine the similarity of all analyzed samples.

The aim of this master thesis is synthesis of SiO2/Au core/shell nanoparticles. These nanoparticles should improve the signal of optical coherence tomography (OCT). The procedure of nanoparticle synthesis is described in the work. Synthetized nanoparticles were analyzed by scanning electron microscopy (SEM), Ultraviolet-Visible spectroscopy (UV-Vis), Near-infrared spectroscopy (NIRS), Fourier transform-infrared spectroscopy (FT-IR) and Dynamic light scattering (DLS). Then, the synthetized nanoparticles were tested for enhancement of OCT signal. For this testing were also used commercial nanoparticles with the same structure and similar size.

Theoretical part of this master thesis was focused on literature recherché dealing with the formation of thin films, plasma, plasma analyses using mass spectrometry and plasma polymerization. Further, this section describes the analysis of thin films using optical methods such as spectroscopic ellipsometry and FT-IR spectrometry. Experimental part describes the materials which are used for the preparation of thin films as well as a description of the equipment for preparation of thin films using a technology of plasma-enhanced chemical vapor deposition (PE-CVD). Control of deposition conditions and monitoring of plasma with its products result in high reproducibility of thin films. The last part of the thesis describes the results of measurement of the first group of samples and their ellipsometric, mass spectrometry and FT-IR evaluation with respect to the deposition conditions.

In der vorliegenden Arbeit wurde die kationische Polymerisation der heterocyclischen Monomere 2-Vinylfuran, 5-Methyl-2-vinylfuran und 2-Vinylthiophen in der Gegenwart silikatischer Partikel untersucht. Produkte dieser Reaktion sind Polymer/SiO2-Hybridpartikel und lösliche Polymere. Zu ihrer Untersuchung wurden NMR-spektroskopische Verfahren, IR-, UV/Vis-, MALDI TOF-Spektroskopie, Elementaranalyse und GPC angewandt. Damit gelang es, die Struktur der Polymere weitgehend aufzuklären. Der Einfluß der Reaktionsbedingungen auf die Ergebnisse der kationischen Oberflächenpolymerisation wurde untersucht und diskutiert. Die Ausbildung vernetzter Polymere bei der kationischen Polymerisation von 2-Vinylfuran bewirkte eine besonders starke Anbindung der Poly(2-vinylfuran)-Schicht und hohe Polymergehalte an den SiO2-Partikeln. Im Falle des Poly(2-vinylthiophens) (PVT) waren die Polymergehalte der Hybridpartikel deutlich niedriger. Es wurde eine lineare Polymerstruktur vorgeschlagen. Poly(2-vinylthiophen) und Poly(2-vinylthiophen)/Kieselgel-Hybridpartikel wurden in polymeranalogen Reaktionen mit Hydridakzeptoren und FeCl3 umgesetzt. Ziele dieser Reaktionen waren die Erzeugung von konjugierten Strukturelementen und die kontrollierte Vernetzung des Polymers über Bisthiopheneinheiten. Der Einfluß der Reaktionszeit und der Natur der eingesetzten Reagenzien auf die Reaktion von PVT mit Hydridakzeptoren wurde ausführlich studiert. Der Einfluß der Reaktionsbedingungen auf die Vernetzungsreaktion mit FeCl3 wurde mit Hilfe von GPC, IR- und 13C{1H}-CP/MAS-NMR-Spektroskopie untersucht. / The following work examines the cationic polymerization of the heterocyclic monomers 2-vinylfuran, 5-methyl-2-vinylfuran und 2-vinylthiophen mediated by silica particles. The products of this reaction are polymer/SiO2-hybridpartikels and a soluble polymer part. For characterization of the products NMR-spectroscopical methods, IR-, UV/Vis-, MALDI TOF-spectroscopy, elemental analysis and GPC were used. With the help of this methods it succeeded to clear up the polymer structure. The influence of the reaction conditions on the results of the cationic polymerization was examined and discussed. Extensive crosslinking of the 2-vinylfuran monomer during cationic polymerization causes a very strong linkage of the poly(2-vinylfuran)-layer and a hight polymer content of the poly(2-vinylfuran)/SiO2-hybridpartikels. In case of poly(2-vinylthiophen) (PVT) the polymer content of the hybrid particles was notedly lower. A linear polymer structure was supposed. The reaction of poly(2-vinylthiophen) and poly(2-vinylthiophen)/silica hybrid particles with hydridacceptors and FeCl3 was studied. The objectives of this reactions were to generate conjugated structures and to cross-link the polymer by creating bisthiophene structures in a controlled manner. The influence of the reaction time and the nature of the acceptors on the reaction of PVT with the hydride acceptors was examined in detail. The influence of the reaction conditions on the cross-linking reaction with FeCl3 was studied with the help of GPC, IR- und 13C{1H} CP/MAS NMR spectroscopy.