In nature, urea is hydrolyzed to ammonia and bicarbonate primarily by enzymes called ureases. As urine waste contains multiple important plant nutrients, there is interest in the waste treatment field to use urine waste products as plant fertilizers. Since urease enzymes are usually found in biofilms, one can prevent nitrogen loss in urine waste by preventing biofilm formation in the surrounding environment. In recent years, many new strategies to prevent microbial growth have been developed, especially within the field of nanoscience. The aim of this master's thesis was to develop a method for growing and analyzing urease-active biofilms and to investigate whether super-acidic metal- oxide surfaces could prevent biofilm growth. In this project, the methods are divided into two sections: methods for producing super-acidic metal-oxide surfaces and methods for growing and analyzing biofilms. The method for growing biofilms was developed through successive experiments, with the results of one experiment being used to design the next. Three batches of antimicrobial plates were manufactured, and seven biofilm experiments were conducted. In these experiments, biofilms were able to grow on antimicrobial plates, but the results were somewhat inconclusive. The biofilms were analyzed by microscopy, since no quantitative analysis method was successful in this study.

A series of segmented poly (epsilon-caprolactone) polyurethane-ureas (PCLUUs) were prepared from poly (epsilon-caprolactone) (PCL) diol, different dissociates and chain extenders to improve the recovery stress of shape memory polymers. NMR and FT-IR were used to identify the structure of the synthesized shape memory polyurethane-ureas. Parameters such as soft segment content (molecular weight and content), chain extender and the rigidity of the main chain were investigated to understand the structure-property relationships of the shape memory polymer systems through DSC, DMA, physical property test, etc. Cyclic thermal mechanic tests were applied to measure the shape memory properties which showed that the recovery stress can be improved above 200% simply by modifying the chain extender. Meanwhile, the synthesis process was optimized to be similar to that of Spandex /LYCRA®. Continuous fibers were made from a wet spinning process, which indicated excellent spinnability of the polymer solution. Small angle neutron scattering (SANS) was used to study the morphology of the hard segment at different temperatures and stretch rates and found that the monodisperse rigid cylinder model fit the SANS data quite well. From the cylinder model, the radius of the cylinder increases with the increasing hard segment content. The SANS results revealed phase separation of hard and soft segments into nano scale domains.

Small stock farming and production accounted for approximately 8.4% of total animal product based agricultural output in the 2011 / 2012 season in South Africa. Large scale commercial farming aside, small stock farming also takes on an important role in poorer and developing rural areas of South Africa, where small stock are kept for a combination of economic and non-economic reasons including financial investment or security, food and resource production, as well as religious or traditional reasons. Blowflies are Dipterids with complex life cycles and complete metamorphoses, causing damage to hides and frequent death in their ovine hosts, as a result of cutaneous myiasis caused by the larval stages. All economically important blowfly species causing veterinary myiasis belong to the superfamily Oestroidea, which contains the three major families Oestridae, Calliphoridae and Sarcophidae. The two most significant blowfly genera in South Africa, Lucillia and Chrysomya, both belong to the family Calliphoridae. Chemical means of preventing and treating blowfly strike by topical application remains the most widely used method and appears to be indispensable at this stage. New molecules or formulations effective against blowfly strike are constantly being sought and form part of an active field of research. Bayer currently manufactures and markets Drastic Deadline Extreme ®, a pour-on formulation containing flumethrin and fluazuron for the control of blue ticks (Rhipicephalus decoloratus) in cattle; its possible action against blowflies in sheep was investigated in an in-vitro model, subsequent to a pilot pharmacokinetic study evaluating the kinetics of fluazuron when applied topically to sheep in this particular combination. The first objective of the project was to determine whether fluazuron has any effect at all on the development of blowfly larvae. An active ingredient from the same family of compounds, namely triflumeron, has been successfully used for several years to control blowfly strike in sheep in South Africa (Zapp ® Pour on - Bayer), but it was uncertain whether or not fluazuron would be effective. Raw fluazuron was applied to six pieces of beef according to a dose calculation based on the registered dose of the test product in cattle, while another six pieces were treated with saline in a similar fashion (n=6). Each piece of beef was placed in its own container along with six late instar larvae and placed in the incubator at 35°C for a further nine days. In this instance, the treated group demonstrated significant development defects with regard to pupation (uneclosed pupae) when analysed using the Mann-Whitney non-parametric t-test (p = 0.002). / Dissertation (MSc)--University of Pretoria, 2016. / Paraclinical Sciences / MSc / Unrestricted

Part I . Mechanistic intermediates were discovered in the Henry condensations of partially and non-protected pyranoses with a free anomeric hemiacetal function with nitromethane in various solvents for the syntheses of C-glycopyranosides in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/molecular sieves catalyst system. Part II . Syntheses of glycosyl cyanides were optimized with a new catalyst system. Mechanism of cyanation with trimethylsilyl cyanide (TMS-CN) in the presence of the mild and recyclable Lewis acid HgBr 2 in nitromethane were proposed for the syntheses of 1,2-trans per- O -acetylated C-glycopyranosyl cyanides. Part III . Tri-O-acetyl-β-L-fucopyranosyl cyanide and Pd-H 2 , in presence of BOC-anhydride, gave N-BOC-mono- and -di-(2,3,4-tri-O-acetyl-β-L-fucopyranosylmethyl)-amines, which allow for the syntheses of small cluster oligosaccharide mimetics of fucopyranosylomethyl-substituted ureas. From di-(2,3,4-tri-O-acetyl-β-L-fucopyranosylmethyl) amine was also prepared a carbamoyl chloride as potentially useful synthon for preparation of more complex C-glycosidic conjugates.

No description available.

Les travaux exposés dans ce manuscrit s’articulent autour de l’élaboration de nouvelles plateformes pyridylalkylamines polyfonctionelles et chirales afin de permettre le développement d’un nouveau processus de réactions catalysées en cascade. La première partie de ce document décrit la synthèse de plateformes pyridylméthylamines (pma) portant des motifs chiraux et (thio)urées. La seconde partie traite de leur utilisation dans des réactions d’organocatalyse et de métallocatalyse asymétriques, puis dans des réactions catalysées en cascade séquencée. La troisième partie porte sur la synthèse de plateformes pyridyléthylamines (pea) via l’utilisation d’une réaction d’amination électrophile organocatalysée et une réaction de cyclisation de Prins. / The works described in this manuscript is dealing with the construction of new polyfunctional chiral pyridylmethylamine (pma) platforms in order to allow the development of new one-pot catalytic reaction sequences. The first part of this document focuses on the synthesis of pyridylméthylamine platforms carrying chiral motifs and (thio)ureas. The second part reports their use in asymmetric organocatalysis and metallocatalysis and then in catalyzed cascade reaction sequences. The third part deals with the synthesis of pyridyléthylamine (pea) platforms through an organocatalyzed electrophilic reaction followed by a Prins cyclisation.

Die Umsetzung des Park-Nucleotids zu Lipid I in der bakteriellen Zellwandbiosynthese wird durch das Enzym MraY katalysiert. Dieses Enzym ist ein interessantes, bisher ungenutztes Target für neuartige Antibiotika. In der vorliegenden Dissertation wurde das fluoreszenzmarkierte Park-Nucleotid, welches für MraY-Assays geeignet ist, totalsynthetisch dargestellt. Die Synthese konnte ausgehend von kommerziell erhältlichem N-Acetylglucosamin in 14 Stufen mit einer Gesamtausbeute von 4 % erfolgreich durchgeführt werden. Dabei wurden einige Schritte auf Basis einer literaturbekannten Synthese gründlich optimiert und neue Wege zur Darstellung des Peptids und anschließender Kupplung mit einem Kohlenhydrat Baustein gefunden. Im Zuge dieser neuen Syntheseroute wurde die Uridindiphosphat-N-Acetylmuraminsäure, als Substrat für MurC-Assays, synthetisiert. Dies gelang in einer achtstufigen Synthese ausgehend von der geschützten N-Acetylmuraminsäure in einer Gesamtausbeute von 15 %. Die Muraymycine, eine Klasse von natürlichen Nucleosid-Antibiotika, inhibieren das Enzym MraY effizient. In dieser Dissertation wurde der Grundstein für die Synthese möglichst vielfältiger vereinfachter Muraymycin Analoga gelegt, welche potentielle Inhibitoren für MraY darstellen. Die Harnstoffpeptidseitenkette wurde variiert, um den Einfluss dieses Strukturbausteins auf die Inhibitor-Aktivität intensiver untersuchen zu können. Der Ersatz der anspruchsvoll zu synthetisierenden Aminosäure Epicapreomycidin durch die kommerziell erhältlichen Aminosäuren L-Lysin, L-Ornithin, L-Arginin, L-Alanin und L-Methionin konnte die Synthese der Harnstoffpeptidkette stark vereinfachen. Des Weiteren wurde durch eine stereospezifische Synthese die geschützte 2S,3S-Diaminohexansäure dargestellt, um das in den natürlichen Muraymycinen enthaltene L-Hydroxyleucin, welches häufig mit einer Fettsäure verestert ist, zu ersetzten. Dieses sollte durch den Austausch einer Esterbindung durch eine Amidbindung zu einer Stabilisierung der Muraymycin Derivate führen. Unter Verwendung des in dieser Dissertation beschriebenen Lysin-haltigen Harnstoffpeptids wurden vor kurzen vereinfachte Muraymycin-Analoga synthetisiert und IC50 Werte mittels eines fluoreszenzbasierten MraY-Assays bestimmt. Diese stark vereinfachten Verbindungen weisen bereits gute Inhibitor Aktivitäten auf. Durch die Kombination der verschiedenen, in dieser Arbeit synthetisierten Harnstoffpeptide und Aminosäuren mit unterschiedlichen Uridinderivaten kann zukünftig eine große Anzahl diverser potentieller Inhibitoren dargestellt werden.

Made available in DSpace on 2016-08-10T10:29:46Z (GMT). No. of bitstreams: 1 GLADSTONE SANTOS DE SOUZA.pdf: 1638209 bytes, checksum: 55969fd3f801a5d3226ae0a527951dc1 (MD5) Previous issue date: 2009-05-11 / The bovine tick is the ectoparasite that causes the greatest prejudice to Brazilian farming and cattle raising, and its control is realized basically through chemical products, which are losing effectiveness over time. This work aimed to evaluate the efficacy of a transdermal formulation, developed by the laboratory Clarion Biociências Ltd. It contains the medicine novaluron, against the tick Boophilus microplus in naturally infested animals. Animals used in the experiment were kept in a pasture with Brachiaria brizantha ascendancy, water; animal food and mineral salt were supplied ad libitum. The formulation containing novaluron was tested in five different dosages: 5.0; 2.5; 1.66; 1.25 and 1.0mg/kg of live weight in a single dose compared to a placebo group and control. The weight of the animals of the experiment varied from 290 to 339kg. Only the dosages of 5.0 and 2.5mg/kg attended the least requisites. The evaluation of the plasmatic profiles of the dosages of 2.50 and 5.00mg/kg of novaluron, presented the following results respectively: concentration peak (Cmax) was 378 and 396ng/mL; the time for obtainment of the concentration peak (Tmax) was 4 days for both dosages and the area on the plasmatic concentration curve(ASC) > 100ng was 28 and 42 days. Based on the results of efficacy and analysis of the plasmatic profile it was concluded that the 2.5mg/kg dosage presented a better relation cost/ benefit. Afterwards it was realized the efficacy of the formulation of novaluron 5% in the dosage of 2.5mg/kg live weight in a single dose comparatively to the commercial product fluazuron, formulation containing 2.5% of fluazuron in the dosage of 2.5mg/kg in a single dose compared to the group control. The results for the two products were alike. It was concluded that a formulation containing 5% of novaluron in the 2.5mg/kg dosage owns the safety requisites, efficacy and economic which make feasible complementary studies for register and commercialization. / O carrapato bovino é o ectoparasita que causa o maior prejuízo à agropecuária brasileira, e o seu controle é realizado basicamente através de produtos químicos, os quais vêm perdendo eficácia com o passar do tempo. O presente trabalho teve como objetivo avaliar a eficácia de uma formulação transdérmica, desenvolvida pelo laboratório Clarion Biociências Ltda. contendo o fármaco novaluron, frente ao carrapato Boophilus microplus em animais naturalmente infestados. Os animais utilizados no experimento foram mantidos a pasto com predomínio de Brachiaria brizantha, água, ração e sal mineral foram fornecidos ad libitum. A formulação contendo novaluron foi testada em cinco posologias diferentes: 5,0; 2,5; 1,66; 1,25 e 1,0mg/kg de peso vivo, em dose única comparativamente a um grupo placebo e controle. O peso dos animais do experimento variou de 290 a 339kg. Somente as posologias de 5,0 e 2,5mg/kg atenderam os requisitos mínimos. A avaliação dos perfis plasmáticos das posologias de 2,5 e 5,0mg/kg de novaluron, apresentaram os seguintes resultados respectivamente: pico de concentração (Cmax) foi de 378 e 396ng/mL; o tempo para obtenção do pico de concentração (Tmax) foi de 4 dias para ambas as posologias e a área sobre a curva de concentração plasmática (ASC) > 100ng foi de 28 e 42 dias. Com base nos resultados de eficácia e análise do perfil plasmático, concluiu-se que a posologia de 2,5mg/kg apresentou uma melhor relação custo/benefício. Posteriormente foi realizada eficácia da formulação de novaluron 5% na posologia de 2,5mg/kg de peso vivo em dose única comparativamente ao produto comercial fluazuron, formulação contendo 2,5% de fluazuron na posologia de 2,5mg/kg em dose única comparadas ao grupo controle. Os resultados para os dois produtos foram semelhantes. Concluiu-se que formulação contendo 5% de novaluron na posologia de 2,5mg/kg possui os requisitos de segurança, eficácia e econômicos que viabilizam estudos complementares para registro e comercialização.

The isoquinoline-catalyzed synthesis of pretended 1H-azirines from phenacyl bromides and N,N\'-dialkylcarbodiimides was repeated. The products do not possess the structure of antiaromatic 1H-azirines, but simple N-acyl-N,N\'-dialkylureas were formed instead. This structural corrigendum was confirmed by the independent synthesis of the known ureas and comparison of their 1H NMR and 13C NMR spectroscopic data in the case of six compounds. Thus,1H-azirines keep their classification as very short-lived intermediates.

Chlortoluron is a herbicide from the group of substituted ureas and it is used for weed control in production of cereals and poppy. Substituted ureas are widely used but these substances are known for their high mobility in soil, persistence and contamination of underground water. Therefore, the development of analytical methods suitable for residual concentrations determination is necessary. This thesis deals with the determination of chlortoluron using carbon paste electrode (CPE) by the methods of differential pulse voltammetry and high-performance liquid chromatography with electrochemical (HPLC-ED) and spectrophotometric (HPLC-UV) detection. The aim of the work was to find optimal conditions suitable for chlortoluron determination. Further, the possibility of using miniaturized carbon paste electrode (mCPE) and usability of tested methods for determination of chlortoluron in model samples of river water and soil were studied. Concentration dependences in deionized water were measured by the method of DPV in the Britton-Robinson (BR) buffer (pH = 3) and methanol (10 %, v/v). The limit of detection was 3,7∙10-7 mol∙dm-3 in the case of CPE and 8,7∙10-8 mol∙dm-3 in the case of mCPE. Also, concentration dependences were measured using HPLC with mobile phase containing BR buffer (pH = 4) and...