No description available.

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.

The purpose of this report was to examine a method for automatic maze solving by developing a robot that can find a specific target within a maze. On this basis, a Arduino based robot was constructed. The steering mechanism was constructed in a way that supports differential steering which enables zero radius turns which is preferred in narrow spaces. The intersection detection as well as the method for defining which type of intersection occurring was based on three distance sensor mounted in front and on the left and right side of the robot. The target detection was based on a IR sensor. A feedback controller was applied on the left Ultrasonic sensor enabling the robot to keep a reference distance to the wall. The feedback system also enabled the robot to straighten up when taking to big or small turns. The robot was able to both detect and define what kind of intersection occurring as well as detect the specific target. The execution of the correct operation by detected intersection was calculated to 80% - 100% and the target was found 100% out of the test made. The definition of ”correct operation” in this report was when the robot detected a intersection, and executed the operation that was in accordance with the implemented algorithm. The rotational error, that is the quantity of degrees from the desired turn angle, occurring when the robot executed different operations was calculated to 3.5◦ - 9.5◦ . The robot started to oscillate due to angles grater than 19.5◦ when the left distance sensor was facing the wall which made the robot less able to follow a path and straighten up. / Syftet med denna rapport var att undersöka en metod för automatiserad labyrintlösning genom att utveckla en robot som kan finna ett specifikt mål i en labyrint. På dessa grunder konstruerades en arduinobaserad robot. Styrmekanismen konstruerades på sådant sätt att differentialstyrning var möjlig vilket tillät svängar utan svängradie, vilket är att föredra vid trånga utrymmen. Vägkorsningsdetekteringen samt metoden för att bestämma vilken typ av vägkorsning som förekommer baserades på tre distansmätare. Dessa var monterade på robotens front samt på höger och vänster sida. Måldetekteringen var baserad på en IR sensor. Ett system medåterkoppling implementerades på den vänstra distansmätaren för att få roboten att hålla ett referensavstånd till väggen. Detta möjliggjorde även så att vägen kunde följas på ett optimalt sätt samt att roboten kunde rätas upp vid för stora eller för små tagna svängar. Roboten lyckades både detektera samt definiera vilken typ av vägkorsning som uppstod likväl som att detektera det specifika målet. Andelen utförda korrekta operationer vid detekterande av vägkorsning beräknades till 80% - 100% av fallen och målet detekterades 100% av gångerna vid det gjorda testerna. Definitionen av ”korrekt operaton ”i denna rapport var då roboten upptäckte en vägkorsning och utförde den operation som var i enlighet med den implementerade algoritmen. Rotationsfelet, det vill säga antalet grader från den önskade svängvinkeln, som uppstod vid de olika operationerna beräknades till 3.5◦ - 9.5◦ . Roboten började att oscillera vid vinklar större än 19.5◦ då den vänstra distansmätaren var vänd mot väggen vilket gjorde roboten mindre duglig att följa väggen samt att rätas upp.

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.

This essay aims to ascertain whether an impulse response is able to accurately simulatethe sound of an amplifier with a clean tone. This is done with a visual analysis of thewaveforms from both a re-amped audio signal and one with a convolution reverb/loaderwith an impulse measurement of the amplifier. And an audio evaluation with musicallyknowledgeable individuals. The results show small visual differences on the waveformsand no participant in the audio evaluation test was able to tell which was an impulseresponse. Leading to the conclusion that an impulse response could simulate theamplifier with great accuracy.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

No description available.

This research, focusing mainly on tocotrienols, includes two parts. The first part concerns the uptake and growth inhibition of tocotrienols in PC-3 cells. The second part is a study of the physiochemical properties of Vitamin E. In the cellular study our results suggested that position 5 of chroman head and side-chain are very important in determining the uptake of tocotrienols and growth inhibition of PC-3 cells. The uptake and growth inhibition are not necessarily related to the antioxidant properties of tocotrienols. Of the physiochemical studies, the results suggested that the antioxidant properties of vitamin E are due to the phenolic O-H group. In ethanol solution, each tocotrienol has a higher oxidation potential than its corresponding tocopherol. The oxidation potentials of vitamin E are in the order ofα-form < γform < δ-form. The theoretical calculations show that the side chains of tocotrienols are less ordered than those of tocopherols.

Pulsed laser flash photolysis of M(CO)6 (M = Cr, W) in cyclohexane with a small amount of benzene results in three sequential reactions. The first is the photodissociation of the parent to yield a M(CO)5:C6H12 complex, which takes place faster than the time resolution of our experiments. The second reaction is the replacement of the cyclohexane ligand with benzene to form a M(CO)5:C6H6 complex, in which benzene is coordinated to the metal via one side of the ring. This complex then falls apart in solution as M(CO)5 coordinates with a trace impurity in the solution that is likely water. Kinetic studies over a range of temperatures result in the following activation energies: 39 kJ/mol for the dissociation of W(CO)5:C6H6; 30 kJ/mol for conversion of Cr(CO)5:C6H12 to Cr(CO)5:C6H6; 33 kJ/mol for the dissociation of Cr(CO)5:C6H6. DFT calculations of binding energies for each complex suggest that all reactions proceed through a combination of an associative and dissociative mechanism. Further calculations of carbonyl vibrational frequencies for 13 weak metal–solvent complexes using three different density functionals: B3LYP, M06, and M06-L allowed us to calculate scale factors for predicting experimental vibrational frequencies. The scale factors are: 0.952 for B3LYP, 0.943 for M06, and 0.957 for M06-L. Using these scale factors leads to average errors in predicted experimental vibrational frequencies of less than 1% for each functional.

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