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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

VIBRATIONAL SPECTROSCOPY ANALYSES OF THE DEGRADATION AND CONTAMINATION OF ENGINE OIL LUBRICANTS COUPLED WITH MULTIPLE SPECTROSCOPIC TECHNIQUES

Holland, Torrey 01 August 2018 (has links)
The spectral analysis techniques afforded us from the field of physics has enabled us to explore the spectral signatures of trace contaminants and degradation products in used or in service engine oil through atomic and molecular spectroscopy. Here we have examined the need to address proper preparation of calibrating samples for infrared spectroscopy analysis by inducing emulsification and have evaluated multiple procedures for proper emulsification of samples with the intent to help establish the protocols that are not explicitly set forth in the ASTM International standard. We have also explored the use of Fourier-transform infrared spectroscopy techniques to examine the suppression of the O–H stretching mode of water due to the influence of ethylene glycol, which may help in the quantification of water when both are present in oil. This was done in conjunction with exploring alternative methods for direct and indirect measurement of the glycol contamination by use of UV/Vis spectroscopy, Raman, and laser-induced breakdown spectroscopy. An exploration of FT-IR and UV/Vis data on the oxidation of oil by means of ANOVA calculations has led to the reporting of highly significant differences in the data of differing oxidation times and in regions of the spectrum not known to have been previously reported.
92

Novas metodologias espectroscópicas e eletroquímica aplicando classificação multivariada em sistemas biológicos

Lima, Leomir Aires Silva de 16 March 2018 (has links)
Submitted by Automação e Estatística (sst@bczm.ufrn.br) on 2018-06-15T20:23:52Z No. of bitstreams: 1 LeomirAiresSilvaDeLima_TESE.pdf: 12936588 bytes, checksum: 3b95baa9be2f99c235dfe55bfa524efc (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-06-18T19:26:42Z (GMT) No. of bitstreams: 1 LeomirAiresSilvaDeLima_TESE.pdf: 12936588 bytes, checksum: 3b95baa9be2f99c235dfe55bfa524efc (MD5) / Made available in DSpace on 2018-06-18T19:26:42Z (GMT). No. of bitstreams: 1 LeomirAiresSilvaDeLima_TESE.pdf: 12936588 bytes, checksum: 3b95baa9be2f99c235dfe55bfa524efc (MD5) Previous issue date: 2018-03-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esta tese demonstra o desenvolvimento de novas metodologias instrumentais como: espectroscopias no infravermelho próximo e médio, de fluorescência molecular e voltametria de pulso diferencial, combinadas a técnicas de classificação multivariada e seleção de variáveis, aplicadas a sistema biológico como tecido, larvas de mosca e plasma sanguíneo. Em um primeiro estudo, a espectroscopia NIR foi utilizada para obtenção de espectros de crânio de rato saudáveis e com defeito crítico. Modelos multivariados de classificação foram construídos, visando uma metodologia alternativa para estimar a taxa de sucesso do reparo ósseo através dos tratamentos com laser de baixa intensidade e colágeno. Os algoritmos PCA- LDA, SPA-LDA e GA-LDA foram aplicados como ferramentas de classificação e seus desempenhos comparados. De maneira geral, os modelos foram capazes de classificar o grupo controle dos demais mostrando eficiência na avaliação da cicatrização de feridas em defeito craniano de rato. Em um segundo estudo, a espectroscopia ATR-FTIR foi utilizada para obtenção de espectros de plasmas sanguíneos de idosos saudáveis e portadores de sarcopenia. Modelos multivariados de classificação foram construídos, visando uma metodologia de diagnóstico para triagem de idosos sarcopênicos. Os algoritmos PCA-LDA, SPA-LDA e GALDA foram aplicados como ferramentas de classificação e seus desempenhos comparados. De maneira geral, os resultados obtidos através do algoritmo de seleção de variáveis SPA-LDA e GA-LDA foram os mais satisfatórios alcançando sensibilidade de 86,7%, pois puderam ser relacionadas a grupos funcionais pertencentes a diferentes biomoléculas e possíveis biomarcadores. Em um terceiro estudo, a voltametria de pulso diferencial e matrizes de excitação/emissão de fluorescência molecular foram obtidas para extratos de larvas de mosca controle e contendo o fármaco flunitrazepam. Foi avaliado o desempenho dos algoritmos de classificação com métodos de seleção de variáveis e funções discriminante linear (sensibilidade de 90%) e quadrática (sensibilidade de 100%) para os voltamogramas e o algoritmo 2D-LDA (sensibilidade de 100%) comparado ao PARAFAC-LDA (sensibilidade de 40%) para classificação entre os grupos investigado. Os resultados sugerem que métodos espectroscópicos e eletroquímicos somados à análise multivariada são capazes de minerar informações relevantes a cerca do entendimento da dinâmica biológica de diversos organismos, como também contribuir com o sistema de saúde pública na identificação de sarcopenia em idosos e classificar insetos contendo drogas. / This thesis demonstrates the development of new instrumental methodologies such as: near and medium infrared spectroscopy, molecular fluorescence and differential pulse voltammetry, combined with multivariate classification and variable selection techniques applied to biological system such as tissue, fly larvae and blood plasma. In a first study, NIR spectroscopy was used to obtain healthy and critically defective rat skull spectra. Multivariate classification models were constructed, aiming at an alternative methodology to estimate the success rate of bone repair through low intensity laser and collagen treatments. The algorithms PCA-LDA, SPA-LDA and GA-LDA were applied as classification tools and their comparative performances. In general, the models were able to classify the control group of the others showing efficiency in the evaluation of wound healing in rat cranial defect. In a second study, ATR-FTIR spectroscopy was used to obtain blood plasma spectra of healthy elderly patients with sarcopenia. Multivariate classification models were constructed, aiming at a diagnostic methodology for screening of sarcopenic elderly. The algorithms PCA-LDA, SPA-LDA and GA-LDA were applied as classification tools and their comparative performances. In general, the results obtained through the SPA-LDA and GA-LDA variable selection algorithm were the most satisfactory, achieving sensitivity of 86.7%, since they could be related to functional groups belonging to different biomolecules and possible biomarkers. In a third study, differential pulse voltammetry and molecular fluorescence excitation / emission matrices were obtained for extracts of control fly larvae and containing the drug flunitrazepam. The performance of classification algorithms was evaluated using linear discriminant (90% sensitivity) and quadratic (100% sensitivity) methods for the voltamograms and the 2D-LDA algorithm (sensitivity of 100%) compared to PARAFAC - LDA (sensitivity of 40%) for classification between the groups investigated. The results suggest that spectroscopic and electrochemical methods added to the multivariate analysis are capable of mining relevant information about the understanding of the biological dynamics of several organisms, as well as contributing to the public health system in the identification of sarcopenia in the elderly and classify insects with drugs.
93

Estudo de compatibilidade entre atorvastatina e excipientes por t?cnicas t?rmicas (TG, DSC) e FTIR utilizando correla??o de pearson / Study of compatibility between atorvastatin and excipients by thermal techniques (TG, DSC) and FTIR using pearson correlation

Silva, Edilamar Pereira da 29 July 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-20T21:49:25Z No. of bitstreams: 1 EdilamarPereiraDaSilva_DISSERT.pdf: 3623493 bytes, checksum: a0b5d0f1284a116519496496c1ba17b3 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-23T18:49:31Z (GMT) No. of bitstreams: 1 EdilamarPereiraDaSilva_DISSERT.pdf: 3623493 bytes, checksum: a0b5d0f1284a116519496496c1ba17b3 (MD5) / Made available in DSpace on 2017-03-23T18:49:31Z (GMT). No. of bitstreams: 1 EdilamarPereiraDaSilva_DISSERT.pdf: 3623493 bytes, checksum: a0b5d0f1284a116519496496c1ba17b3 (MD5) Previous issue date: 2016-07-29 / A atorvastatina ? um medicamento antilip?mico do grupo das estatinas, de grande import?ncia para a preven??o de doen?as cardiovasculares e normalmente usada como atorvastatina de c?lcio. O objetivo deste trabalho foi caracterizar a atorvastatina e estudar poss?veis intera??es desta com v?rios excipientes por DSC, TG e FT-IR. As curvas DSC foram obtidas usando o calor?metro SHIMADZU, modelo DSC-60, em cadinho de alum?nio sob raz?o de aquecimento de 20 ?C min-1, em uma temperatura de 25-400 ?C. As curvas foram analisadas usando o software TASYS da SHIMADZU. Os espectros das amostras foram obtidos em um espectrofot?metro ATR-FTIR modelo IRprestige-21 da Shimadzu, no comprimento de onda de 700 a 4000 cm-1 em uma m?dia de 20 varreduras. Avaliou-se a const?ncia espectral da atorvastatina e misturas bin?rias fazendo-se uma correla??o linear entre o espectro te?rico das amostras e o espectro real obtido em temperatura ambiente (25 ?C). O espectro te?rico foi obtido utilizando um algoritmo ad hoc. Por DSC avaliamos intera??es com manitol e laurilsulfato de s?dio, j? que houve desaparecimento do pico do f?rmaco e aparecimento apenas do pico do excipiente, caracterizando intera??o. A partir da avalia??o da correla??o de Pearson, n?o observamos intera??es f?sicas com os excipientes, glicolato de amido, amido pr? gelatinizado, croscarmelose, estearato de magn?sio e lactose, uma vez que o valor do r ficou entre 0,8 e 1,0, portanto boa correla??o. H? intera??es f?sicas com o laurilsulfato de s?dio. Assim, os resultados obtidos por DSC s?o confirmados por FTIR mostrando-se. Essas t?cnicas mostram-se extremamente efetivas no estudo de pr?-formula??o. / Atorvastatin is an antilipemic drug from the statins? group that has a great importance to prevent cardiovascular disease and it is usually used as atorvastatin calcium. The aim of this study was to characterize the atorvastatin and studying possible interactions with different excipients by DSC, TG and FTIR. DSC curves were obtained using a Shimadzu calorimeter, model DSC-60, aluminum pan, under heating rate of 20 ?C min-1 at temperature of 25-400 ?C. Consequently, curves were analyzed using TASYS software from Shimadzu. The spectra of the samples were obtained on a spectrophotometer ATR-FTIR (IRPrestige- 21 Shimadzu), between 700 and 4000 cm-1, on average of 20 scans. We evaluated the atorvastatin and binary mixtures? spectral steadiness by making a linear correlation between the theoretical spectra and the real ones obtained at room temperature (25 ?C). The theoretical spectra were obtained using an ad hoc algorithm. We evaluated by DSC that there are chemical interactions with mannitol and sodium lauryl sulfate because there was disappearance of the drug?s peak and appearance only of the excipients? peaks. With respect to the other excipients, there were only displacements of peaks suggesting physical interactions, it means no incompatibility. From the FTIR evaluation using Person?s correlation, it was not observed any physical interaction between atorvastatin and the following excipients: starch glycolate, pregelatinized starch, croscarmellose, magnesium stearate and lactose, since the value of r was between 0.8 and 1.0; in other words, it means a good correlation. Moreover, it was confirmed a physical interaction with the sodium lauryl sulfate. Finally, the results obtained by DSC were confirmed by FTIR data using the Person?s correlation, so both analytical techniques demonstrated to be extremelly important and effective tools for applying in a preformulation study.
94

Investigation of HIV anti-viral drug effect on HPV16 E6 expressing cervical carcinoma cells using advanced metabolomics methods

Kim, Dong Hyun January 2011 (has links)
Metabolomics approaches have recently been used to understand the complex molecular interactions of biological systems. One popular area in which these methods are being developed is to understand the biochemical changes during abiotic and biotic stresses; for example, how a cell may respond to a drug. Since metabolites are the end products of gene expression, these can be used to indicate the result of the activities and interaction of the cell or organism with its environment. The investigation of the level and compositional changes of metabolites against metabolic stresses such as chemotherapeutic treatment (drug exposure) are required to understand more fully abiotic perturbation to biological systems. The aim of this project was to understand the metabolic effect that the anti-viral drugs indinavir and lopinavir (currently used by HIV patients) have on HPV-related cervical cancer cell lines by measuring changes in metabolism using a wide range of analytical techniques; including Fourier transform infrared (FT-IR) and Raman spectroscopies, and gas and liquid chromatography-mass spectrometry (GC and LC-MS). The analyses and interpretation of the large volumes of complex multidimensional data generated by metabolomics approaches were performed with a combination of multivariate data analysis techniques such as principal components analysis (PCA) and canonical variates analysis (CVA), as well as univariate approaches such as N-Way analysis of variance (ANOVA). By combining biochemical imaging, metabolite fingerprinting and footprinting, and metabolite profiling, with multi- and uni-variate analyses, the actions and effects of the anti-viral drugs were investigated. FT-IR spectroscopy was initially used to generate global biochemical finger- and foot-prints, and Raman spectroscopy was employed to investigate intracellular distribution of metabolites, and other cellular species, as well as the localisation of drug molecules within cells. FT-IR spectroscopy ascertained that the intra- and extra-cellular metabolomes were being directly influenced in a fashion that correlated with increasing anti-viral dosing; these effects were phenotypic rather than measurements of the drug level. Raman imaging spectroscopy indicated that the indinavir but not lopinavir was being compartmentalised within the cell nucleus, but only in HPV early protein 6 (E6) expressing cells. This observation was further confirmed by fractionation of cell samples into nuclear and cytoplasmic fractions and assessing the indinavir concentrations via LC-MS. Finally, LC-MS and GC-MS metabolite profiling were employed to investigate changes in the intracellular metabolome in response to the anti-viral compounds across a range of physiologically relevant concentrations and in the presence and absence of the E6 oncoprotein. General effects of both anti-viral compounds included the regulation of metabolites such as glutathione, octenedionoic and octadecenoic acids, which may be involved in stress related responses, reduced levels of sugars and sugar-phosphates indicating a potential arrest of glycolysis, and reduced levels of malic acid indicating potential decreased flux into the TCA cycle; all indicating that central metabolism was being reduced. Finally, LC-MS based quantification indicated that in the presence of E6, lopinavir was actively removed from the cell, whereas the indinavir intracellular concentration increased concomitantly with the level of dosing. These investigations have revealed that metabolomics approaches are an apt tool for the study of anti-viral effects within cell cultures, but improvements need to be made with respect to the major limitation of metabolite identification.
95

In situ-IR-spektroskopische Untersuchungen zur MTS-Thermolyse

Hemeltjen, Steffen 13 October 2003 (has links)
In dieser Arbeit wird beschrieben, wie sich die in situ-IR-Spektroskopie zur Charakterisierung von CVD-Prozessen einsetzen läßt. Es werden Modellreaktoren vorgestellt, deren Konstruktion an die spektroskopische Verfolgung thermisch aktivierter Gasphasenreaktionen angepaßt ist. Ausgehend von Referenzmessungen, mit deren Hilfe Möglichkeiten und Grenzen der FT-IR-Spektroskopie in Bezug auf die CVD-Prozeßanalytik aufgezeigt werden, können auftretende Species im untersuchten System sicher bestimmt werden. Im Mittelpunkt der Arbeit steht die Untersuchung der Gasphase bei der Thermolyse von Methyltrichlorsilan in Abhängigkeit von den Prozeßparametern Temperatur und Eduktgaszusammensetzung. Die gefundenen Korrelationen werden durch Thermolysen einzelner, nachgewiesener Verbindungen bestätigt. Eine weitere Absicherung der Ergebnisse erfolgt durch Isotopenmarkierung mit Deuterium. Untersuchungen zur Schichtbildung ergänzen die Gasphasenanalytik. Auf Grundlage der nachgewiesenen stabilen und instabilen Species und deren Abhängigkeit von den Prozeßparametern wird ein Mechanismus vorgeschlagen und diskutiert, der die Thermolyse von Methyltrichlorsilan zur Abscheidung von Siliciumcarbid vollständig beschreibt.
96

Differentiation of Fungal Phytopathogens by FT-IR and MALDI-TOF MS

Atkinson, Curtis Muldrow 14 December 2013 (has links)
The use of matrix assisted laser desorption ionization time-oflight mass spectrometry, Fourier transform infrared spectroscopy, and other analytical means of identifying and differentiating microorganisms hold much promise. These analytical tools have been extensively assessed for their ability to differentiate bacteria and fungi. Most of this research has been coordinated in medically relevant microorganisms, but the technology can work just as well with agriculturally important microorganisms. In this thesis, these technologies were reviewed and then subsequently studied for their ability to differentiate Aspergillus species (that devastate corn and other crops yearly with aflatoxin contamination), as well as Macrophomina phaseolina and Thielaviopsis basicola which limit yields on soybean and other crops yearly. With the use of these technologies, harmful plant pathogens could be identified and subsequently treated to improve crop yields and also help to protect our nation and state’s food supply.
97

Chemical and physical structure of the barrier against water transpiration of leaves: Contribution of different wax compounds / Chemischer und physikalischer Aufbau der Wassertranspirationsbarriere von Blättern: Beitrag verschiedener Wachskomponenten

Seufert, Pascal January 2021 (has links) (PDF)
The cuticle is constituted of the biopolymer cutin and intra- and epicuticular waxes. In some cases, it has epicuticular wax crystals, protruding from the epicuticular wax film. One of the most important tasks is protection against desiccation. Many investigations were conducted to find the transport limiting component of the cuticle. It is evidentially confirmed that the waxes form this barrier. These waxes are multifactorial blends made of very-long-chain aliphatic (VLCA) compounds and triterpenoids (TRP). The VLCAs were proposed to constitute the transpiration barrier to water. However, experimental confirmation was lacking so far. The present study focuses on the development of a method to selectively extract TRPs from the cuticle and the impact of the removal on the transpiration barrier. The plants deployed in this study exhibited several features. They had no epicuticular crystals on their surfaces, were astomatous, had a rather durable and possibly isolatable cuticle. A broad range of wax compositions was covered from plants with no TRP content and low wax load like Hedera helix and Zamioculcas zamiifolia to plants with high TRP content and high wax load like Nerium oleander. The selective extraction was conducted using a sequence of solvents. TRPs were extracted almost exhaustively from CMs with the first MeOH extract. Only a minor amount of shorter chained VLCAs was obtained. The remaining waxes, consisting mostly of VLCAs and some remnant TRPs, were removed with the following TCM extract. After the extractions, the water permeance of native cuticular membranes (CM), MeOH extracted (M) and dewaxed cuticular discs (MX) was investigated gravimetrically. Compared to the water permeance of CMs, Ms showed no or only a small increase in water conductance. MXs, however, always showed strongly increased values. The knowledge about the wax compounds constituting the transport-limiting properties is vital for different projects. For various issues, it would be favourable to have a standardized wax mixture as an initial point of research. It could be used to develop screening procedures to investigate the impact of adjuvants on cuticular waxes or the influence of wax constituents on the properties of cuticular waxes. This work concentrated on the development of an artificial wax mixture, which mimics the physical properties of a plant leaf wax sufficiently. As target wax, the leaf wax of Schefflera elegantissima was chosen. The wax of this plant species consisted almost exclusively of VLCAs, had a rather simple composition regarding compound classes and chain length distribution and CMs could be isolated. Artificial binary, ternary and quaternary waxes corresponding to the conditions within the plant wax were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD) techniques and Fourier-transform infrared (FTIR) spectroscopy. Phase diagrams were mapped out for a series of binary, ternary and quaternary wax mixtures. FTIR experiments were conducted using, ternary and a quaternary artificial wax blends. The blends were chosen to represent the conditions within the wax of the adaxial CM plant wax. The FTIR experiments exhibited an increasing resemblance of the artificial wax to the plant wax (adaxial CM wax) with an increasing number of compounds in the artificial wax. The same trend was found for DSC thermograms. Thermograms of ternary and quaternary blends exhibited more overlapping peaks and occurred in a temperature range more similar to the range of the whole leaf plant wax. The XRD spectrum at room temperature showed good conformity with the quaternary blend. The current work illustrates a method for selective extraction of TRPs from isolated CMs. It gives direct experimental proof of the association of the water permeance barrier with the VLCA rather than to the TRPs. Furthermore, the possibility to mimic cuticular waxes using commercially available wax compounds is investigated. The results show promising feasibility for its viability, enabling it to perform as a standardized initial point for further research (e.g. to examine the influence of different constituents on waxes), revealing valuable knowledge about the structure and the chemistry-function relationship of cuticular waxes. / Die Kutikula ist eine der vielen Anpassungen, die Pflanzen entwickelten um nach der Besiedelung des Landes mit den Herausforderungen ihrer neuen Umgebung fertig zu werden. Sie überzieht überirdische Pflanzenorgane, wie Blüten oder Blätter und erfüllt verschiedene Aufgaben. Hierzu besteht sie aus dem biopolymer Kutin und intra- sowie epikutikulären Wachs. Studien, die sich mit der Lokalisierung der transporteinschänkenden Barriere beschäftigten, zeigten, dass die Wachse sie bilden. Diese sind vielschichtige Mischungen aus langkettigen aliphatischen Verbindungen (VLCA) und pentazyklischen Verbindung wie Triterpenen (TRP). Es wird davon ausgegangen, dass VLCAs die Barriere aufbauen, ein direkter experimenteller Nachweis dafür wurde jedoch noch nicht erbracht. In dieser Arbeit wurde daher ein Verfahren zur selektiven Extraktion von TRPs aus isolierten kutikulären Membranen (CM) entwickelt und deren Auswirkung auf die Transpirationsbarriere untersucht. Die untersuchten Pflanzen wiesen keine epikutikuläre Kristalle auf, hatten keine Stomata auf der Kutikula der Blattoberseite und es war möglich ihre Kutikula zu isolieren. Die Zusammensetzung der Wachse variierte von wenig Wachs ohne TRPs (z. B. Hedera helix, Zamioculcas zamiifolia) hin zu pflanzen mit großer Wachsmenge und hohem TRP- Anteil (Nerium oleander). Die selektive Extraktion wurde durch die sequenzielle Nutzung zweier Lösemittel erreicht. TRPs wurden fast vollständig mit Methanol (MeOH) entfernt, während VLCAs überwiegend nur mit Chloroform (TCM) extrahiert werden konnten. Die gravimetrische Bestimmung der Wassertranspiration von unbehandelten, mit Methanol extrahierten (M) und entwachsten Membranen (MX) in Transpirationskammern zeigte bei allen untersuchten Pflanzenarten einen einheitlichen Trend auf. Im Vergleich zu CMs erhöhte sich die Transpirationsrate bei Ms nicht oder nur geringfügig, während bei MXs ein starker Anstieg festgestellt werden konnte. Diese Ergebnisse stellen den ersten direkten experimentellen Nachweis der Verbindung von VLCAs zur Transpirationsbarriere kutikulärer Wachse dar. Mit dem Wissen, sich bei der Untersuchung der Permeation durch die Kutikula sich nur auf die VLCA Fraktion beschränken zu müssen können weitere Projekte effizient angegangen werden. Ein leicht erhältliches Standartwachsgemisch könnte Ausgangspunkt für die Untersuchung des Einflusses verschiedener Pflanzenwachskomponenten auf deren physikalische Eigenschaften dienen. Als Zielwachs diente das Blattwachs von Schefflera elegantissima. Es bestand fast ausschließlich aus VLCAs, hatte eine recht einfache Zusammensetzung bezüglich der Stoffklassen und Kettenlängenverteilung und die Kutikula war isolierbar. Mit Hilfe von dynamische Differentialkalorimetrie (DSC), Röntgenbeugung (XRD) und Fouriertransformierter Infrarot (FTIR) Spektroskopie wurden binäre, ternäre und quaternäre Gemische, die Verhältnisse im Pflanzenwachs wiederspiegelten, untersucht und Phasendiagramme erstellt. Phasendiagramme wurden von einer Reihe der binären Gemische, bestehend aus Alkanen oder Alkoholen, ternären Gemischen aus zwei Alkanen und einem Alkohol und quaternären Gemischen aus zwei Alkanen und zwei Alkoholen erstellt. FTIR-spektroskopische Versuche zeigten mit zunehmender Komponentenzahl eine erhöhte Ähnlichkeit der artifiziellen Wachse zum Pflanzenwachs (adaxiale isolierte Kutikula). Ein ähnlicher Trend wurde für die Ähnlichkeit der Thermogramme der artifiziellen Gemische zum Pflanzenwachs (aus dem Extrakt ganzer Blätter) ersichtlich. Das Diffraktogramm des quaternären Waches stimmte auf Raumtemperatur gut mit dem des Pflanzenwachses (adaxiale isolierte Kutikula) ein. Diese Arbeit beschreibt eine Methode zur selektiven Extraktion von TRPs aus isolierten kutikulären Membranen. Sie zeigt einen direkten experimentellen Nachweis für die Assoziation der Transpirationsbarriere zu den VLCAs und nicht zu den TRPs. Zusätzlich wird die Möglichkeit kutikulare Wachse mit Hilfe von kommerziell erhältlichen Wachskomponenten nachzustellen untersucht, was vielversprechende Ergebnisse liefert. Dieses Wachs könnte daher als standardisierter Ausgangspunkt für weitere Experimente (z. B. zur Untersuchung des Einflusses verschiedener Wachskomponenten auf dessen physikalische Eigenschaften) dienen. Dies könnte wertvolle Informationen über die Struktur und die Beziehung zwischen chemischer Zusammensetzung und der Funktion kutikulärer Wachse liefern.
98

Chemical Mechanisms and Microstructural Modification of Alloy Surface Activation for Low-Temperature Carburization

Illing, Cyprian A W 01 June 2018 (has links)
No description available.
99

The Synthesis and Characterization of Imidazolium Lithium Phthalocyanines

Kelley, John J. 26 September 2008 (has links)
No description available.
100

Data Analysis Strategies for Airborne Remote Sensing of Volatile Organic Compounds Using Passive Fourier Transform Infrared Spectrometry

Tarumi, Toshiyasu 30 June 2004 (has links)
No description available.

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