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Development and Characterization of Ethanol-Compatibilized PPO-Based EPMM MembranesWang, Qiang January 2011 (has links)
Emulsion polymerized mixed matrix (EPMM) membranes is a new category of membranes, which incorporate silica-based inorganic nanoparticles dispersed in continuous phase of an organic polymer. The uniqueness of the EPMM membranes comes from the fact that they may combine otherwise incompatible inorganic and organic phases. This is achieved by the synthesis of the inorganic nanoparticles from a silica precursor in a stable emulsion, in which an aqueous phase is dispersed in a continuous phase of the polymer solution. More specifically, the silica precursor soluble in the polymer solution polymerizes in contact with the aqueous phase, and consequently the latter acts as finely dispersed micro reactors.
The objective of this work was to optimize the previously developed protocol for the synthesis of poly (2,6-dimethyl-1,4pheneylene oxide) (PPO) based EPMM membranes, and to characterize their physical and gas transport properties. In particular, the effects of inorganic loading and the membrane post-treatment protocol on the permeability and selectivity of the membranes were of interest. However, the results showed that the obtained permeation and separation were virtually not affected by the theoretical Si loading and the post-treatment protocol. Moreover, in comparison to the base PPO membranes, the observed O2 permeability and the O2/N2 permselectivity have generally decreased. The differential scanning calorimetry (DSC) analysis of the synthesized membranes showed an important scatter of the glass transition temperatures (Tg) of the EPMM membranes with the values generally lower than the Tg of the base PPO. Moreover, the inductively coupled plasma mass spectrometry (ICP-MS) showed the silica content in selected EPMM membranes to be far below the expected theoretical level. This, in combination with the 29Si nuclear magnetic resonance (29Si NMR) results, showed that most of the already low silica content comes from the unreacted silica source (tetraethylorthosilicate) and have led to the second phase of the project in which a modified synthesis protocol has been developed.
The major differences of the modified protocol compared to the original one include the replacement of a surfactant, 1-octanol, by ethanol and using greater concentrations of the reactants. To study the effect of different parameters involved in the synthesis protocol, a Gravimetric Powder experiment, in which the inorganic polymerization is carried out in an emulsion with a pure solvent rather than a polymer solution, has been designed. The Gravimetric Powder experiments have confirmed polymerization of tetraethylorthosilicate (TEOS) in the emulsion system. Using the conditions, which resulted in the maximum production of the polymerized TEOS in the Gravimetric Powder experiments, one set of new EPMM membranes has been synthesized and characterized.
The new EPMM membranes have the Tg of 228.2oC, which is distinctly greater compared to the base PPO, and contain one order of magnitude more of silica compared to the old EPMM membranes. More importantly, the 29Si NMR analysis has proven that the silica content in the new EPMM membranes originates from the reacted rather than unreacted TEOS. Interestingly, the observed conversion of TEOS in the new EPMM membranes, exceeding 20%, is greater than the largest conversion in the Gravimetric Powder experiments. The oxygen permeability in the new EPMM membrane of 33.8 Barrer is more than twice that of the base PPO membrane. Moreover, this increase in O2 permeability is associated with a modest increase in the O2/N2 permselectivity (4.75 versus 4.67).
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Filmes de polipirrol como matrizes para a imobilização da polifenol oxidase e aplicação como biossensores amperométricos na análise de compostos fenólicos / Polypyrrole film as matrix for the immobilization of polyphenol oxidase and application as amperometric biosensors in the analysis of phenolicElys Raquel Andrade Ferreira 14 December 2007 (has links)
Nesta dissertação, a polifenol oxidase (PFO) como extrato bruto de abacate (Persea americana) foi imobilizada em filmes de polipirrol (PPI) sintetizados eletroquimicamente utilizando o glutaraldeído (GA) como um agente de ligação entrecruzada. Os filmes PPI e PPI/PFO-GA foram caracterizados por eletroquímica, principalmente voltametria cíclica, sendo avaliadas a eletroatividade e a reversibilidade eletroquímica. A detecção de compostos fenólicos em soluções padrão foi feita por cronoamperometria, tendo um controle sobre a concentração dos compostos. O processo de transferência de massa foi monitorado com uma microbalança de cristal de quartzo eletroquímica. Os resultados indicaram uma boa reprodutibilidade das medidas na detecção dos compostos fenólicos. A estabilidade do biossensor em uma solução tampão manteve-se durante 27 dias, um resultado aceitável já que é encontrado na literatura um tempo de vida estável para sistemas semelhantes em tomo de 30 dias / In this dissertation, polyphenol oxidase (PPO) as crude extract of avocado (Persea americana) was immobilized on electrochemical1y synthesized polypyrrole (PPY) films using glutaraldehyde (GA) as a crosslinking agent. PPY and PPY/PPO-GA films were electrochemical1y characterized, mainly by cyclic voltametry, where electroactivity and electrochemical reversibility were evaluated. The detection of phenolic compounds in standard samples was made by chronoamperometry with a control over the compound concentration. The process of mass transfer was monitored with an electrochemical quartz crystal microbalance (EQCM). Our results indicated a good repeatability of the measurements for the detection of phenolic compounds. The stability of biosensor in a buffer solution has remained for 27 days, a result acceptable since it is found in the literature a time of life stable for similar systems around 30 days
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Influência do contra-íon usado na eletrossíntese do polipirrol em sua resposta como biossensor eletroquímico após a imobilização da polifenol oxidase / Influence of counter-ion used in the electrosynthesis of polypyrrole in your response as electrochemical biosensors after polyphenol oxidase immobilizationValquiria da Cruz Rodrigues Barioto 16 July 2009 (has links)
Neste trabalho, foram fabricados biossensores amperométricos a partir do uso da polifenol oxidase (PFO), obtida do abacate como fonte enzimática, imobilizada em filmes de polipirrol (PPI) e que foram eletrossintetizados em meio de três diferentes eletrólitos de suporte (NaCl e NaClO4 e NaDDS). O método de imobilização enzimática foi o da adsorção, sendo a solução de enzima adicionada à solução com o pirrol e o eletrólito durante o processo de eletropolimerização. Os filmes de PPI/PFO foram caracterizados por técnicas eletroquímicas, principalmente por voltametria cíclica. A detecção de compostos fenólicos (catecol e pirogalol) foi realizada pela técnica de cronoamperometria após se variar a concentração do analito. A morfologia dos filmes foi estudada por microscopia de força atômica (AFM), sendo observado que a presença da enzima no filme polimérico assim como o uso de diferentes eletrólitos de suporte levou a diferenças na superfície dos filmes. Além disto, verificou-se que o biossensor construído a partir do uso do NaCl, apresentava uma resposta mais eficiente, ou seja, ele foi capaz de detectar catecol e pirogalol em um menor limite de detecção. / In this study amperometric biosensors were manufactured from the use of polyphenol oxidase (PPO) obtained from avocado as a source of enzyme immobilized in polypyrrole (PPY) films that were electrosynthesized with three different support electrolytes (NaCl, NaClO4 and NaDDS). The method of enzyme immobilization was the adsorption. The PPO was added in the solution containing pyrrole and electrolyte during electropolymerization. The PPY/PPO films were characterized by electrochemical techniques mainly by cyclic voltammetry. Detection of phenolic compounds (catechol and pyrogallol) was performed by the technique of chronoamperometry after varying the concentration of the analyte. The morphology of the films was studied by the atomic force microscopy (AFM) and observed that the presence of the enzyme in the polymer film and the use of different electrolytes support led to differences in the surface of films. However it was found that the biosensor constructed from the use of NaCl showed more efficient response and it was able to detect catechol and pyrogallol in a lower limit of detection.
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End-to-End Autonomous Driving with Deep Reinforcement Learning in Simulation EnvironmentsWang, Bingyu 10 April 2024 (has links)
In the rapidly evolving field of autonomous driving, the integration of Deep Reinforcement Learning (DRL) promises significant advancements towards achieving reliable and efficient vehicular systems. This study presents a comprehensive examination of DRL’s application within a simulated autonomous driving context, with a focus on the nuanced impact of representation learning parameters on the performance of end-to-end models. An overview of the theoretical underpinnings of machine learning, deep learning, and reinforcement learning is provided, laying the groundwork for their application in autonomous driving scenarios. The methodology outlines a detailed framework for training autonomous vehicles in the Duckietown simulation environment, employing both non-end-to-end and end-to-end models to investigate the effectiveness of various reinforcement learning algorithms and representation learning techniques.
At the heart of this research are extensive simulation experiments designed to evaluate the Proximal Policy Optimization (PPO) algorithm’s effectiveness within the established framework. The study delves into reward structures and the impact of representation learning parameters on the performance of end-to-end models. A critical comparison of the models in the validation chapter highlights the significant role of representation learning parameters in the outcomes of DRL-based autonomous driving systems.
The findings reveal that meticulous adjustment of representation learning parameters markedly influences the end-to-end training process. Notably, image segmentation techniques significantly enhance feature recognizability and model performance.:Contents
List of Figures
List of Tables
List of Abbreviations
List of Symbols
1 Introduction
1.1 Autonomous Driving Overview
1.2 Problem Description
1.3 Research Structure
2 Research Background
2.1 Theoretical Basis
2.1.1 Machine Learning
2.1.2 Deep Learning
2.1.3 Reinforcement Learning
2.2 Related Work
3 Methodology
3.1 Problem Definition
3.2 Simulation Platform
3.3 Observation Space
3.3.1 Observation Space of Non-end-to-end model
3.3.2 Observation Space of end-to-end model
3.4 Action Space
3.5 Reward Shaping
3.5.1 speed penalty
3.5.2 position reward
3.6 Map and training dataset
3.6.1 Map Design
3.6.2 Training Dataset
3.7 Variational Autoencoder Structure
3.7.1 Mathematical fundation for VAE
3.8 Reinforcement Learning Framework
3.8.1 Actor-Critic Method
3.8.2 Policy Gradient
3.8.3 Trust Region Policy Optimization
3.8.4 Proximal Policy Optimization
4 Simulation Experiments
4.1 Experimental Setup
4.2 Representation Learning Model
4.3 End-to-end Model
5 Result
6 Validation and Evaluation
6.1 Validation of End-to-end Model
6.2 Evaluation of End-to-end Model
6.2.1 Comparison with Baselines
6.2.2 Comparison with Different Representation Learning Model
7 Conclusion and Future Work
7.1 Summary
7.2 Future Research
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Autonomous Navigation with Deep Reinforcement Learning in Carla SimulatorWang, Peilin 08 December 2023 (has links)
With the rapid development of autonomous driving and artificial intelligence technology, end-to-end autonomous driving technology has become a research hotspot. This thesis aims to explore the application of deep reinforcement learning in the realizing of end-to-end autonomous driving. We built a deep reinforcement learning virtual environment in the Carla simulator, and based on it, we trained a policy model to control a vehicle along a preplanned route. For the selection of the deep reinforcement learning algorithms, we have used the Proximal Policy Optimization algorithm due to its stable performance. Considering the complexity of end-to-end autonomous driving, we have also carefully designed a comprehensive reward function to train the policy model more efficiently. The model inputs for this study are of two types: firstly, real-time road information and vehicle state data obtained from the Carla simulator, and secondly, real-time images captured by the vehicle's front camera. In order to understand the influence of different input information on the training effect and model performance, we conducted a detailed comparative analysis. The test results showed that the accuracy and significance of the information has a significant impact on the learning effect of the agent, which in turn has a direct impact on the performance of the model. Through this study, we have not only confirmed the potential of deep reinforcement learning in the field of end-to-end autonomous driving, but also provided an important reference for future research and development of related technologies.
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Biochemische Charakterisierung von PpoA aus Aspergillus nidulans / Biochemical Characterisation of PpoA from Aspergillus nidulansBrodhun, Florian 28 October 2009 (has links)
No description available.
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Interaction of PPO-inhibitor herbicide mixtures and mechanistically studies thereof / Interação de herbicidas inibidores da PPO e estudos fisiologicamente relacionadosMenzani, Ana Paula Meirelles 26 October 2017 (has links)
Crop production provides the food and fiber necessary to sustain the world\'s population. Effective weed management is critical to maintaining agricultural productivity. Intensive or continuous use of herbicides that act on the same target site, or are detoxified by similar processes within crops and target weeds frequently results in the development of weeds resistant to a specific herbicide or class of herbicides. Weed resistance due to the extensive use of glyphosate in glyphosate tolerant crop systems has become one of the most serious issues facing agriculture today. Thus PPO-inhibitor herbicides are an alternative mechanism of action that have the potential to mitigate the development of resistant weeds in weed control systems where crop tolerance is sufficient to allow them to be effectively deployed. While there are few reports of weed resistance to PPO-inhibitor herbicides it has not developed to the extent that it is a commercial problem for growers. When used at recommended doses, they typically have favorable regulatory profiles. Furthermore, most of them are highly compatible with no-tillage agriculture. However, PPO-inhibitor herbicides are typically more active on dicots than monocots. This thesis provides information with regards to effectiveness of certain binary mixtures of PPO herbicides as weed control agents. The mixtures showed synergistic effects and could control monocots as Echinochloa crus-galli and volunteer corn besides control the dicots species. Regarding the compounds studied, trifludimoxazin and flumioxazin required less amount of compound to inhibit 50% of PPO2 activity in all plants species tested, while sulfentrazone and saflufenacil, one of the best mixtures in the field, showed that needed bigger concentrations to inhibit 50% of the PPO2 compared to other compounds evaluated.The absorption and translocation of these compounds individually or in mixtures, showed that as single compounds, the absorption was slower in maize than E. crus-galli and there was no difference among the herbicides except trifludimoxazin, that was significantly lower than the other compounds. Saflufenacil was the herbicide that showed the best translocation out of treated leaf point, while trifludimoxazin has not shown any translocation out of leaf treated. In mixtures, the compounds showed some differences in absorption and translocation, which it was variable according to species studied. Some traits of PPO-tolerant were also evaluated in Arabidopsis thaliana which indicates potential traits to be developed in crops of interest. / Agricultura é responsável por fornecer alimento e fibras necessárias para sustentar a população mundial. Controle de plantas daninhas é essencial para obter uma boa produtividade. O uso intensivo de herbicidas que age no mesmo sitio de ação ou são detoxificados por processos similares pelas plantas daninhas resulta geralmente no desenvolvimento de plantas daninhas resistentes a um herbicida específico ou à uma classe de herbicidas. A resistência de plantas daninhas devido ao uso de culturas tolerantes à glifosato tem se tornado um dos mais sérios problemas na agricultura. Inibidores da PPO pode ser uma ferramenta para mitigar o desenvolvimento de plantas daninhas resistentes. Há poucos relatos de plantas daninhas resistentes a este mecanismo de ação. Quando aplicados na dose recomendada, apresentam perfil toxicológico favorável e além disso, a maioria dos herbicidas deste grupo são compatíveis com plantio direto. No entanto, são mais eficientes em dicotiledôneas do que em monocotiledôneas. O objetivo dessa tese foi fornecer informações em relação a associação binária de herbicidas inibidores da PPO no controle de plantas daninhas. As associações mostraram efeito sinérgico no controle de Echinochloa crus-galli e milho voluntário, além do controle de dicotiledôneas. Avaliou-se também a atividade de alguns inibidores da PPO na inibição de 50% da enzima PPO2 e observou-se que para inibir 50% da PPO2 necessitou de menor quantidade de trifludimoxazin e flumioxazin em todas as plantas testadas, enquanto que sulfentrazone e saflufenacil, que associados apresentaram a melhor eficácia nos ensaios de campo, mostraram que precisar de maiores concentrações para inibir a PPO2 comparada aos outros produtos. A absorção e translocação destes produtos, isolados ou em mistura, mostraram que a absorção foi mais lenta em milho do que em E. crus-galli. Os herbicidas apresentaram comportamentos similares, sendo absorvidos quase 95% até 72 horas após aplicação, com exceção do trifludimoxazin, que foi significativamente mais lento que os outros. Saflufenacil foi o herbicida que apresentou melhor translocação na folha aplicada, enquanto trifludimoxazin não apresentou nenhuma translocação. Em relação às associações, os produtos mostraram diferenças na absorção e translocação, variando conforme as plantas daninhas estudadas. Alguns eventos tolerantes a inibidores da PPO foram avaliados em Arabidopsis thaliana e indicaram como potenciais eventos para ser desenvolvidos nas culturas de interesse.
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Influencia de los factores pre y postcosecha en la calidad de la lechuga IV GamaLuna Riquelme, Mª Consuelo 20 December 2012 (has links)
En la presente Tesis Doctoral se estudió la influencia de algunos factores agronómicos como el riego, soluciones nutritivas, además de la comparación de dos sistemas: cultivo en suelo (tradicional) y sin suelo. Debido a la gran importancia del estado de madurez de la materia prima para la industria de IV Gama, se realizó una recopilación bibliográfica sobre indicadores de madurez en vegetales de hoja y se llevó a cabo un ensayo experimental estudiando el efecto de tres estados de madurez sobre la calidad del producto IV Gama. Finalmente, los factores postcosecha evaluados fueron el efecto de la baja concentración de O2 y las condiciones lumínicas en conservación sobre la calidad del producto en IV Gama. / The aim of this thesis is know the influence of some agronomic factors such as irrigation, nutrient solutions, in addition to the comparison of two systems: soil cultivation (traditional) and soilless system. Due to the great importance of the harvest maturity for Fresh cut industry, we conducted a study on harvest maturity indicators of leafy vegetables and a pilot trial to study the effect of three stages of maturity on product quality Fresh cut was conducted. Finally, postharvest factors evaluated were the effect of the low concentration of O2 and conservation lighting conditions on product quality in Fresh cut.
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Efeito de características da calda e estádio da corda-de-viola na eficácia de carfentrazone-ethyl e saflufenacil / Effect of spray characteristics and morning-glory stage on the efficacy of carfentrazone-ethyl and saflufenacilAgostineto, Mauricio Crestani 18 June 2015 (has links)
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Previous issue date: 2015-06-18 / Weeds can cause significant yield losses in the agriculture, among them we can point out morning-glory species in many crops. To control that weed, we can use herbicides inhibiting protoporphyrinogen IX oxidase, in a selective way for a variety of crops. The objectives were: (i) to relate the response of Ipomoea hederifolia and Ipomoea quamoclit with the variation of doses of carfentrazone-ethyl and saflufenacil, of spray temperature at the moment of spraying, and of spray volume used; and (ii) to compare the efficacy of those herbicides sprayed isolately or mixed to glyphosate. Experiments were carried out from dose-response with carfentrazone-ethyl (0, 0.25, 0.5, 1, 2, 4, 5, 7.5, 10, 20, 35, 50, and 75 g ha-1 of the labeled herbicide Aurora®, 400 g a.i. L-1, FMC) and with saflufenacil (0, 0.125, 0.25, 0.5, 1, 2, 2.5, 5, 7.5, 10, 20, 35, and 50 g ha-1 of the labeled herbicide Heat®, 700 g a.i. kg-1, Basf), of variation of spray temperature (10 to 30 oC) and of variation of spraying volume (150 to 250 L ha-1). Evaluations were performed 14 days after spraying. In spite of showing differential response in relation to the dry mass accumulation, doses from 4 mL ha-1 of Aurora® and 5 g ha-1 of Heat® killed plants for both I. hederifolia and I. quamoclit. For carfentrazone-ethyl, increasing 10 L ha-1 in the spray volume reduced dry mass by 1.43% and 1.26% for I. hederifolia and I. quamoclit, respectively, while for saflufenacil, the reduction was by 12.73% and 11.30%, respectively for both species. For carfentrazone-ethyl, increasing 1 oC of spray temperature of reduced the dry mass by 0.22% and 0.35% for I. hederifolia and I. quamoclit, respectively, while for saflufenacil the reduction was by 0.56% and 0.30%, respectively for both species. The mix of carfentrazone-ethyl or saflufenacil with glyphosate provided a reduction by, at least, 10% greater of dry mass of I. hederifolia. We concluded that: carfentrazone-ethyl and saflufenacil are highly efficient to control I. hederifolia and I. quamoclit; increasing the spray volume and spray temperature provide greater efficacy to control both species, for both herbicides; and the mix with glyphosate improve the efficacy of controlling I. hederifolia for both herbicides / As plantas daninhas podem causar perdas significativas de produtividade na agricultura, dentre as quais se destacam as cordas-de-viola em diversos cultivos. Para seu controle podem ser utilizados herbicidas inibidores da enzima protoporfirinogênio IX oxidase, de maneira seletiva para diversos cultivos. Os objetivos foram: (i) relacionar a resposta de Ipomoea hederifolia e Ipomoea quamoclit com a variação da dose de carfentrazone-ethyl e saflufenacil, da temperatura da calda no momento da aplicação e do volume de calda aplicado; e (ii) comparar a eficácia destes herbicidas aplicados isoladamente e em mistura com glyphosate. Foram realizados experimentos de dose-resposta com carfentrazone-ethyl (0; 0,25; 0,5; 1; 2; 4; 5; 7,5; 10; 20; 35; 50 e 75 g ha-1 do produto comercial Aurora®, 400 g i.a. L-1, FMC) e com saflufenacil (0; 0,125; 0,25; 0,5; 1; 2; 2,5; 5; 7,5; 10; 20; 35 e 50 g ha-1 do produto comercial Heat®, 700 g i.a. kg-1, Basf), de variação de temperatura de calda (10 a 30 oC) e de variação de volume de calda (150 a 250 L ha-1). Avaliações de massa seca foram efetuadas 14 dias após a aplicação. Apesar de apresentarem resposta diferenciada quanto ao acúmulo de massa seca, doses a partir de 4 mL ha-1 de Aurora® e 5 g ha-1 de Heat® causaram a morte de plantas de I. hederifolia e I. quamoclit. Para carfentrazone-ethyl, o aumento de cada 10 L ha-1 no volume de calda aplicado reduziu a massa seca em 1,43% e 1,26% para I. hederifolia e I. quamoclit, respectivamente; enquanto para saflufenacil, a redução foi de 12,73% e 11,30%, respectivamente para essas espécies. Para carfentrazone-ethyl, o aumento de cada 1 oC na temperatura da calda reduziu a massa seca em 0,22% e 0,35% para I. hederifolia e I. quamoclit, respectivamente, enquanto para saflufenacil a redução foi de 0,56% e 0,30%, respectivamente para essas espécies. A mistura de carfentrazone-ethyl ou saflufenacil com glyphosate proporcionou redução de no mínimo 10% maior na massa seca de I. hederifolia. Conclui-se que: carfentrazone-ethyl e saflufenacil são altamente eficazes no controle de I. hederifolia e I. quamoclit; o aumento no volume de calda e na temperatura da calda proporcionam maior eficácia de controle dessas espécies, para ambos os herbicidas; e a mistura com glyphosate aumenta a eficácia de controle de I. hederifolia para ambos os herbicidas
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Interaction of PPO-inhibitor herbicide mixtures and mechanistically studies thereof / Interação de herbicidas inibidores da PPO e estudos fisiologicamente relacionadosAna Paula Meirelles Menzani 26 October 2017 (has links)
Crop production provides the food and fiber necessary to sustain the world\'s population. Effective weed management is critical to maintaining agricultural productivity. Intensive or continuous use of herbicides that act on the same target site, or are detoxified by similar processes within crops and target weeds frequently results in the development of weeds resistant to a specific herbicide or class of herbicides. Weed resistance due to the extensive use of glyphosate in glyphosate tolerant crop systems has become one of the most serious issues facing agriculture today. Thus PPO-inhibitor herbicides are an alternative mechanism of action that have the potential to mitigate the development of resistant weeds in weed control systems where crop tolerance is sufficient to allow them to be effectively deployed. While there are few reports of weed resistance to PPO-inhibitor herbicides it has not developed to the extent that it is a commercial problem for growers. When used at recommended doses, they typically have favorable regulatory profiles. Furthermore, most of them are highly compatible with no-tillage agriculture. However, PPO-inhibitor herbicides are typically more active on dicots than monocots. This thesis provides information with regards to effectiveness of certain binary mixtures of PPO herbicides as weed control agents. The mixtures showed synergistic effects and could control monocots as Echinochloa crus-galli and volunteer corn besides control the dicots species. Regarding the compounds studied, trifludimoxazin and flumioxazin required less amount of compound to inhibit 50% of PPO2 activity in all plants species tested, while sulfentrazone and saflufenacil, one of the best mixtures in the field, showed that needed bigger concentrations to inhibit 50% of the PPO2 compared to other compounds evaluated.The absorption and translocation of these compounds individually or in mixtures, showed that as single compounds, the absorption was slower in maize than E. crus-galli and there was no difference among the herbicides except trifludimoxazin, that was significantly lower than the other compounds. Saflufenacil was the herbicide that showed the best translocation out of treated leaf point, while trifludimoxazin has not shown any translocation out of leaf treated. In mixtures, the compounds showed some differences in absorption and translocation, which it was variable according to species studied. Some traits of PPO-tolerant were also evaluated in Arabidopsis thaliana which indicates potential traits to be developed in crops of interest. / Agricultura é responsável por fornecer alimento e fibras necessárias para sustentar a população mundial. Controle de plantas daninhas é essencial para obter uma boa produtividade. O uso intensivo de herbicidas que age no mesmo sitio de ação ou são detoxificados por processos similares pelas plantas daninhas resulta geralmente no desenvolvimento de plantas daninhas resistentes a um herbicida específico ou à uma classe de herbicidas. A resistência de plantas daninhas devido ao uso de culturas tolerantes à glifosato tem se tornado um dos mais sérios problemas na agricultura. Inibidores da PPO pode ser uma ferramenta para mitigar o desenvolvimento de plantas daninhas resistentes. Há poucos relatos de plantas daninhas resistentes a este mecanismo de ação. Quando aplicados na dose recomendada, apresentam perfil toxicológico favorável e além disso, a maioria dos herbicidas deste grupo são compatíveis com plantio direto. No entanto, são mais eficientes em dicotiledôneas do que em monocotiledôneas. O objetivo dessa tese foi fornecer informações em relação a associação binária de herbicidas inibidores da PPO no controle de plantas daninhas. As associações mostraram efeito sinérgico no controle de Echinochloa crus-galli e milho voluntário, além do controle de dicotiledôneas. Avaliou-se também a atividade de alguns inibidores da PPO na inibição de 50% da enzima PPO2 e observou-se que para inibir 50% da PPO2 necessitou de menor quantidade de trifludimoxazin e flumioxazin em todas as plantas testadas, enquanto que sulfentrazone e saflufenacil, que associados apresentaram a melhor eficácia nos ensaios de campo, mostraram que precisar de maiores concentrações para inibir a PPO2 comparada aos outros produtos. A absorção e translocação destes produtos, isolados ou em mistura, mostraram que a absorção foi mais lenta em milho do que em E. crus-galli. Os herbicidas apresentaram comportamentos similares, sendo absorvidos quase 95% até 72 horas após aplicação, com exceção do trifludimoxazin, que foi significativamente mais lento que os outros. Saflufenacil foi o herbicida que apresentou melhor translocação na folha aplicada, enquanto trifludimoxazin não apresentou nenhuma translocação. Em relação às associações, os produtos mostraram diferenças na absorção e translocação, variando conforme as plantas daninhas estudadas. Alguns eventos tolerantes a inibidores da PPO foram avaliados em Arabidopsis thaliana e indicaram como potenciais eventos para ser desenvolvidos nas culturas de interesse.
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