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The Holt Social Studies Curriculum and The Americans were social studies textbooks edited by Edwin Fenton, John M. Good, and others at the Carnegie-Mellon Center for Project Social Studies. These textbooks were an effort by Fenton and his associates to meet the demands for change in social studies curriculum and related instructional materials. Being produced during an era of social change, revolts, and an unpopular war, the textbooks reflected on controversial issues of that era which eventually led to restrictions on their purchase in Georgia. These restrictions, however, raised issues which made this study possible. The Georgia State Board of Education in 1972 rejected the recommendations of its Professional Textbook Selection Committee to include the social studies textbooks edited, authored, or contributed to by Edwin Fenton on the state's approved textbook list. Only the textbooks on the state’s approved list could be purchased with state funds. This study is an investigation of the Georgia State Board of Education’s ban on the social studies textbooks from the state’s approved textbook list and the subsequent effects of the State Board 1s action on future textbook selection policies in the state. This was the first time in twenty years that members of the Georgia State Board of Education had acted to remove approved textbooks from the Georgia public schools. This study is also significant because the State Board's wording of its action leaves the impression that they were opposed to the author, regardless of his works. This study describes a step by step account of the events which eventually led to the ban on the textbooks. It also describes the subsequent events which led to a change in the state’s textbook selection policies. While parents did not participate in the controversy, policy changes made their participation more likely for textbook controversies in the future. Although the Fenton social studies textbooks were not adopted by the State Board, the approaches used in them are widely used in other social studies textbooks in Georgia today. For future textbook controversies in Georgia, the writer recommends that the lay representatives on the State’s Textbook Selection Committee be given voting power. The writer believes the controversy reported in this study uncovered an inconsistency between the social science educators in Georgia and the State Board of Education on the goals of the state’s social studies curriculum. Therefore, the writer recommends that the social studies educators develop a clear set of objectives for the social studies curriculum and present them to the State Board of Education for approval. These objectives should be made available to the general public for scrutiny before they become the set goals for the state. Further, the State Board of Education should keep the lines of communication open with the educators of the state. Finally, the writer recommends further study of the uniformity of Georgia's goals in education across the state, especially the social studies goals. Recently, the state has adopted a series of criterion referenced tests which are administered all over the state. A uniform testing system should dictate a uniform set of objectives. / Ed. D.

Non-edible plant biomass (lignocellulose) is a valuable precursor for liquid biofuels, through the processes of pretreatment and saccharification followed by fermentation into products such as ethanol or butanol. However, it is difficult to gain access to the fermentable sugars in lignocellulose, and this problem is principally associated with limited enzyme accessibility. Hence, biomass pretreatments that destroy native cell wall structure and allows enzyme access are required for effective biomass conversion techniques. This research studied two novel pretreatment methods on two wood species: 1) a deep eutectic solvent (DES) that, under heat, swells lignocellulose and partially solubilizes cell wall materials by causing breakage of lignin-carbohydrate linkages and depolymerization of the biomass components, and 2) a chelator-mediated Fenton reaction (CMF) that chemically modifies the nanostructure of the cell wall through a non-enzymatic cell wall deconstruction. After pretreatment, utilizing analytical techniques such as nuclear magnetic spectroscopy, wide angle x-ray scattering, and gel permeation chromatography, samples were analyzed for chemical and structural changes in the solubilized and residual materials. After single stage DES (choline-chloride-glycerol) and two stage, CMF followed by DES pretreatments, lignin/carbohydrate fractions were recovered, leaving a cellulose-rich fraction with reduced lignin and hemicellulose content as determined by compositional analysis. Lignin and heteropolysaccharide removal by DES was quantified and the aromatic-rich solubilized biopolymer fragments were analyzed as water insoluble high molecular weight fractions and water-ethanol soluble low molecular weight compounds. After pretreatment for the hardwood sample, enzyme digestibility reached a saccharification yield of 78% (a 13-fold increase) for the two stage (DES/CMF) pretreated biomass even with the presence of some lignin and xylan remained on the pretreated fiber; only a 9-fold increase was observed after the other sequence of CMF followed by DES treatment. Single stage CMF treatment or single stage DES pretreatment improved 5-fold glucose yield compared to the untreated sample for the hardwood sample. The enhancement of enzymatic saccharification for softwood was less than that of hardwoods with only 4-fold increase for the sequence CMF followed by DES treatment. The other sequence of treatments reached up to 2.5-fold improvement. A similar result was determined for the single stage CMF treatment while the single stage DES treatment reached only 1.4-fold increase compared to the untreated softwood. Hence, all these pretreatments presented different degrees of biopolymer removal from the cell wall and subsequent digestibility levels; synergistic effects were observed for hardwood particularly in the sequence DES followed by CMF treatment while softwoods remained relatively recalcitrant. Overall, these studies revealed insight into two novel methods to enhance lignocellulosic digestibility of biomass adding to the methodology to deconstruct cell walls for fermentable sugars. / Ph. D. / Wood is a valuable material that can be used to produce liquid biofuels. Wood main components are biopolymers cellulose, hemicellulose and lignin that form a complex structure. Nature has locked up cellulose in a protective assembly that needs to be destroyed to gain access to cellulose, convert it to glucose and then ferment it to bioalcohol. This process is principally associated with limited enzyme accessibility. Therefore, biomass pretreatments that deconstruct native cell wall structure and allow enzyme access are required for effective biomass conversion techniques. This research studied two novel pretreatment methods on two wood species: 1) a deep eutectic solvent called glyceline that, under heat, swells wood and partially solubilizes cell wall materials by causing breakage of bonds and converting it into smaller molecules (monomers and oligomers), and 2) a chelator-mediated Fenton system (CMF) that chemically modifies the structure of the cell wall. Pretreatments were tested individually and in sequence in sweetgum and southern yellow pine. After pretreatments, utilizing analytical techniques, fractions were investigated for chemical and structural changes in the solubilized and residual materials. Treated wood samples were exposed to enzymatic conversion. A maximum 78% of glucose yield was obtained for the glyceline followed by CMF pretreated wood. For yellow pine only a 24% of glucose yield was obtained for the CMF followed by glyceline treatment. All these pretreatments presented different degrees of biopolymer removal from the cell wall and subsequent enzyme conversion levels. Overall, these studies revealed insight into two novel methods to enhance wood conversion adding to the methodology to deconstruct cell walls for fermentable sugars.

Los estudios realizados en esta Tesis Doctoral se han centrado en la aplicación de los Procesos de Oxidación Avanzada (AOPs) en condiciones próximas a la neutralidad para la eliminación de contaminantes químicos (contaminantes emergentes) y biológicos (larvas de mejillón cebra) en aguas naturales, mediante aplicación de procesos de fotocatálisis solar heterogénea con TiO2 y foto-Fenton solar a pH neutro. Los tratamientos de oxidación aplicados a los contaminantes emergentes se han realizado en simulador solar y en planta piloto y su degradación se ha seguido empleando diversas técnicas analíticas ccomo UHPLC, GC-MS, espectroscopía UV-IR (COD, DQO); además se ha realizado un estudio de la evolución de la toxicidad (Vibrio fischeri) durante cada proceso. Los estudios con TiO2 en simulador solar consiguen eliminar la totalidad de los contaminantes en menos de 240 minutos, observándose un aumento de la toxicidad del 50% a los 120 minutos de tratamiento, que prácticamente desaparece al final del proceso; cunado el proceso se escala a planta piloto se aprecia una ralentización en todas las degradaciones justificada por la diferencia entre los espectros (solar y simulador solar) en la región de 280-300nm. Del estudio destaca el hecho de que el rendimiento de las reacciones foto-Fenton en medio neutro es aceptable para su aplicación y está muy influenciado por la concentración inicial de los contamiantes y de ácidos húmicos presentes en el medio, ya que se contraponen su función de estabilización del hierro en disolución, el posible efecto de filtro interno y la acción como atrapador de especies activas. Por otra parte, los ensayos toxicológicos muestran fluctuaciones con el tiempo de tratamiento debido a la generación de intermedios de reacción tóxicos, habiéndose identificado los principales mediante GC-MS. Se ha realizado además un estudio mecanístico sobre la participación del radical hidroxilo en el proceso, siendo menor en medio neutro que en medio ácido. El agua de s / Bernabeu García, A. (2012). APLICACIÓN DE FOTOCATÁLISIS SOLAR A PH NEUTRO PARA LA ELIMINACIÓN DE CONTAMINANTES QUÍMICOS Y BIOLÓGICOS [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17739

Le thème principal de cette recherche est la remédiation des sols contaminés par des hydrocarbures en utilisant des traitements d'oxydation chimique à pH neutre. Les minéraux à base de fer sont susceptibles de catalyser cette réaction d'oxydation. L'étude concerne donc dans un premier temps la synthèse des minéraux réactifs contenant des espèces FeII et FeIII (la magnétite et la rouille verte) et, dans un second temps, leur utilisation pour catalyser l'oxydation chimique. Les procédés d'oxydation testés incluent l'oxydation de type « Fenton-like (FL) » et de type persulfate activé (AP). La formation de la magnétite et de la rouille verte a été étudiée par des transformations abiotiques de différents oxydes ferriques (ferrihydrite, goethite, hématite et lépidocrocite) mis en présence de cations FeII. La magnétite a été utilisée pour catalyser les oxydations (FL et AP) dans la dégradation des hydrocarbures aliphatiques et aromatiques polycycliques (HAP) à pH neutre. Une dégradation importante des hydrocarbures aliphatiques a été obtenue par ces deux oxydants, aussi bien pour des pétroles dégradés naturellement que pour un pétrole brut. L'oxydation catalysée par la magnétite a également été efficace pour la remédiation de deux sols contaminés par HAP provenant d'anciens sites de cokerie. Aucun sous-produit n'a été observé dans nos expériences d'oxydation. En revanche, une très faible dégradation des hydrocarbures a été observée lorsque les espèces FeII solubles ont été utilisées comme catalyseur. Des expériences d'oxydation ont également été réalisées en colonne. Ces études d'oxydation ont révélé l'importance du type de catalyseur utilisé pour l'oxydation, la disponibilité des HAP dans les sols et l'effet de la matrice du sol. Les résultats suggèrent que la magnétite peut être utilisée comme source de fer pour activer les deux oxydations par Fenton-like et persulfate à pH neutre. Ce travail a de fortes implications sur la remédiation par oxydation chimique in situ des sols pollués par des hydrocarbures / The main theme of this research is the use of reactive iron minerals in the remediation of hydrocarbon contaminated soils via chemical oxidation treatments at circumneutral pH. The contribution of this thesis is two-fold including the abiotic synthesis of mixed FeII-FeIII oxides considered as reactive iron minerals (magnetite and green rust) and their use to catalyze chemical oxidation. Oxidation methods tested in this study include Fenton-like (FL) and activated persulfate oxidation (AP). The formation of magnetite and green rust was studied by abiotic FeII-induced transformations of various ferric oxides like ferrihydrite, goethite, hematite and lepidocrocite. Then, the ability of magnetite was tested to catalyze chemical oxidation (FL and AP) for the degradation of aliphatic and polycyclic aromatic hydrocarbons (PAHs) at circumneutral pH. Significant degradation of oil hydrocarbons occurring in weathered as well as in crude oil was obtained by both oxidants. Magnetite catalyzed oxidation was also effective for remediation of two PAHs contaminated soils from ancient coking plant sites. No by-products were observed in all batch slurry oxidation systems. Very low hydrocarbon degradation was observed when soluble FeII was used as catalyst under the same experimental conditions. Magnetite also exhibited high reactivity to catalyze chemical oxidation in column experiments under flow through conditions. Oxidation studies revealed the importance of catalyst type for oxidation, PAHs availability in soils and the soil matrix effect. Results of this study suggest that magnetite can be used as iron source to activate both Fenton-like and persulfate oxidation at circumneutral pH. This study has important implications in the remediation of hydrocarbon polluted soils through in-situ chemical oxidation

Dans cette étude, un nouveau complexe de fer est utilisé dans des processus d’oxydation avancée pour la dégradation de polluants organiques présents dans l’eau. Le fer ferrique (Fe(III)) et l’acide éthylène diamine-N,N’-disuccinique (EDDS) forment un complexe Fe(III)-EDDS dont la structure a été mise en évidence durant ce travail. Les propriétés photochimiques du complexe ont ensuite été évaluées en fonction de différents paramètres physico-chimiques dont le pH qui est apparu comme un paramètre clé pour l’efficacité des processus testés. Ensuite nous avons donc travaillé sur l’utilisation de ce complexe dans les processus de Fenton modifié, photo-Fenton et comme activateur des persulfates (S2O82-). Nos expériences ont été réalisées en présence du 4-tert-butylphénol (4-t-BP) qui est connu pour être un perturbateur endocrinien. Nous avons ensuite mis en évidence les conditions optimales du traitement pour la dégradation du 4-t-BP. Il est apparu que le pH joue un rôle très important et qu’en présence de ce complexe de fer, l’efficacité est plus importante pour des pH neutre ou légèrement basique. L’identification des radicaux oxydants responsables de la dégradation du polluant a également été réalisée. Dans ce cadre nous avons montré que le radical sulfate joue un rôle plus important que le radical hydroxyle lors du processus d’activation des persulfates. / Advanced Oxidation Processes (AOPs) have been proved to be successfully applied in the treatment of sewage. It can decolorize the wastewater, reduce the toxicity of pollutants, convert the pollutants to be a biodegradable by-product and achieve the completed mineralization of the organic pollutants. The Fenton technologies which are performed by iron-activated hydrogen peroxide (H2O2) to produce hydroxyl radical (HO•) has been widely investigated in the past few decades. Recently, Sulfate radical (SO4•-) which was produced by the activation of persulfate (S2O82-) is applied to the degradation of organic pollutants in water and soil. It is a new technology recently developed. It is also believed to be one of the most promising advanced oxidation technologies.In this study, a new iron complex is introduced to the traditional Fenton reaction. The ferric iron (Fe(III)) and Ethylene diamine-N,N′-disuccinic acid (EDDS) formed the complex named Fe(III)-EDDS. It can overcome the main disadvantage of traditional Fenton technology, which is the fact that traditional Fenton technology can only perform high efficiency in acidic condition. Simultaneously, EDDS is biodegradable and it is one of the best environment-friendly complexing agents. On the other hand, the transition metal is able to activate S2O82- to generate SO4•-. Therefore, Fe(III)-EDDS will also be applied to activate S2O82- in the present study. 4-tert-Butylphenol (4-t-BP) has been chosen as a target pollutant in this study. It is widely used as a chemical raw material and is classified as endocrine disrupting chemicals due to the estrogenic effects. The 4-t-BP degradation rate (R4-t-BP) is used to indicate the efficiency of the advanced oxidation processes which are based on Fe(III)-EDDS utilization. The main contents and conclusions of this research are shown as follows:In the first part, the chemical structure and properties of Fe(III)-EDDS and the 4-t-BP degradation efficiency in UV/Fe(III)-EDDS system were studied. The results showed that Fe(III)-EDDS was a stable complex which was formed by the Fe(III) and EDDS with the molar ratio 1:1. From the photoredox process of Fe(III)-EDDS, the formation of hydroxyl radical was confirmed including that HO• is the main species responsible for the degradation of 4-t-BP in aqueous solution. Ferrous ion (Fe(II)) was also formed during the reaction. With the increasing Fe(III)-EDDS concentration, 4-t-BP degradation rate increased but is inhibited when the Fe(III)-EDDS concentration was too high. Indeed, Fe(III)-EDDS is the scavenger of HO•. pH value had a significant effect on the degradation efficiency of 4-t-BP that was enhanced under neutral or alkaline conditions. On the one hand, Fe(III)-EDDS presented in the FeL-, Fe(OH)L2-, Fe(OH)2L3-, Fe(OH)4- four different forms under different pH conditions and they had different sensitivity to the UV light. On the other hand, pH value affected the cycle between Fe(III) and Fe(II ). The formation of hydroperoxy radicals (HO2•) and superoxide radical anions (O2•-) (pka = 4.88) as a function of pH was also one of the reasons. It was observed that O2 was an important parameter affecting the efficiency of this process. This effect of O2 is mainly due to its important role during the oxidation of the first radical formed on the pollutant. (...)

O lixiviado de aterro sanitário possui constituição complexa e é altamente poluente. Neste contexto, os processos oxidativos avançados se destacam como pré-tratamento, objetivando a remoção ou diminuição da recalcitrância do lixiviado. Neste trabalho foram utilizados os Processos Oxidativos Avançados (POAs) foto-Fenton, ozônio e ozônio combinado com peróxido de hidrogênio. Avaliou-se a influência do pré-tratamento por air-stripping, a variação na produção de ozônio em 80 e 100%, a melhor dose de peróxido de hidrogênio correspondente a 20, 40 e 80% da dose de 6g O3/L empregada nos tratamentos com ozônio, a remoção de matéria orgânica, nitrogênio amoniacal total (NAT), alcalinidade, sólidos dissolvidos totais (SDT) (cloretos), produção de nitrito e nitrato, melhor razão molar [H2O2]/[Fe2+] para o tempo de contato de 80 min no foto-Fenton, uso do número médio de oxidação do carbono (NMOC) e a quantificação do ácido oxálico formado após a aplicação dos POAs. O tratamento por O3/H2O2 (1,2 g H2O2/L e produção de O3 em 80%) obteve a maior remoção de matéria orgânica, 0,14 g massa removida de Carbono Orgânico Total (COT) / massa consumida de O3 e 0,43 g/g para a Demanda Química de Oxigênio (DQO). Quanto ao foto-Fenton, averiguou-se o máximo de 74% remoção de COT e 65% remoção DQO para a razão molar [H2O2]/[Fe2+] igual a 2. Também se notou formação de sólidos sedimentáveis neste processo aplicado ao lixiviado bruto. O pré-tratamento por air-stripping não promoveu incremento na remoção de matéria orgânica. As concentrações de NAT, alcalinidade, SDT (cloretos) se mantiveram elevadas após a aplicação dos POA. Ocorreu formação de nitrato em todos os tratamentos. O uso do NMOC foi adequado e demonstrou ocorrência de oxidação nos processos. A quantificação do ácido oxálico formado após a aplicação dos POAs não foi apropriada nesta pesquisa. / The landfill leachate is a major waste produced by the landfill and its constitution complex and highly polluting motivate research in order to adapt their disposal on the environment. In this context, the advanced oxidation processes stand out as a pretreatment, in order to remove or decrease the recalcitrance of the leachate. In this work we used the photo-Fenton AOPs, ozone and ozone combined with hydrogen peroxide. We evaluated the effect of pretreatment for air-stripping, the variation in the production of ozone 80 and 100%, the best dose of hydrogen peroxide equal to 20, 40 and 80% of the dose of 6g O3/ L used in the treatments with ozone, the removal of organic matter, total ammonia nitrogen, alkalinity, dissolved solids (chlorides), production of nitrite and nitrate, best molar ratio [H2O2]/[Fe2+] to the contact time of 80 min in the photo-Fenton, average number of carbon oxidation use and the measurement of oxalic acid formed after application of the AOPs. The AOP O3/H2O2 (1.2g H2O2/L and O3 production by 80%) had the highest removal of organic matter, 0.14 g of TOC removed mass/ mass consumed O3 and 0.43 g/g for COD. As for the photo-Fenton, it was found a maximum of 74% removal of TOC and 65% for COD removal molar ratio [H2O2]/[Fe2+] equal to 2. It was also noted the formation of settle able solids in the process applied to the raw leachate. Pretreatment by air-stripping did not promote an increase in organic matter removal. Total ammonia nitrogen concentrations, alkalinity, dissolved solids (chlorides) remained high after application of the AOP, indicating possible oxidant demand. For nitrate formation occurred in all treatments, while only the photo-Fenton was no formation of nitrite. The use of average number of carbon oxidation was adequate and showed occurrence of oxidation processes. The quantification of oxalic acid formed after the application of AOPs was not appropriate in this research.

Espécies nitrogenadas vem sendo adicionadas ao meio ambiente de forma intensa desde o desenvolvimento do processo Haber-Bosch para transformação de N2 em NH3, alterando significativamente o ciclo biogeoquímico do nitrogênio no ambiente. Uma vez na atmosfera, o nitrogênio reativo é depositado de volta à superfície da Terra por processos de deposição úmida e seca. A importância de levar em conta as formas orgânicas de nitrogênio para estimar a deposição de nitrogênio atmosférico pela chuva (úmida) já é conhecida, no entanto, ainda há poucos trabalhos que avaliam essa fração devido às dificuldades e incertezas impostas pelos métodos analíticos disponíveis. Este trabalho traz o desenvolvimento de um novo método, simples e de baixo custo, para a determinação de nitrogênio orgânico (N-org) em água de chuva utilizando o processo foto-Fenton e um foto-reator construído de forma artesanal. Por meio da adição de solução de Fenton (50 µmol L-1 Fe2+ e 2 mmol L-1 H2O2) e 90 min de radiação UV (85 °C) foi possível obter em média 106 ± 8% de recuperação de nitrogênio para soluções contendo 50 µmol N L-1 das moléculas modelos: ureia, serina, glicina e histidina. No caso da arginina, 90 min de radiação foi suficiente para degradar soluções contendo 10 µmol N L-1. O reator comercial se mostrou mais eficiente na degradação dos compostos testados (30 min), no entanto, com um tempo de 75 min, o reator artesanal atingiu os mesmos resultados. Com o uso de 0,2 g L-1 TiO2 e 120 min de radiação UV, também foi possível obter resultados satisfatórios. Porém, esse método possuiu valores de branco elevados, havendo necessidade de filtrar as amostras irradiadas antes da análise, adicionando tempo e custo ao procedimento analítico. O método desenvolvido utilizando foto-Fenton foi aplicado para a determinação de N-org em amostras de água de chuva coletadas na cidade de Ribeirão Preto (SP) de 2013 a 2017. A concentração de N-org variou de 3,5 a 195 µmol N L-1 com concentração média ponderada pelo volume (MPV) de 17,7 ± 1,0 µmol N L-1 (n=236). Essa média foi maior que aquelas obtidas em água de chuva de várias partes do mundo, podendo ser atribuída a elevada queima de biomassa na região de estudo. As concentrações de aminoácidos livres dissolvidos (AA) representaram em média 15 ± 12% (n=144) em relação à fração orgânica de nitrogênio na chuva, enquanto as concentrações de ureia foram próximas ou inferiores ao limite de quantificação do método (0,5 µmol N L-1). Considerando toda série temporal iniciada no mesmo sítio amostral desde 2005, as concentrações MPV calculadas para os íons NH4+ foi de 22,2 ± 1,1 µmol L-1 (n=460), NO3- de 13,3 ± 0,6 µmol L-1 (n=466), sendo que a concentração de NO2- foi irrelevante. Foram obtidas concentrações significativamente mais elevadas (teste-t, P=0,05) de NH4+, NO3-, N-org e AA no período de safra da cana (seco) com relação à entressafra (chuvoso), para todos os anos avaliados. Apesar da colheita manual da cana ter sido drasticamente reduzida, o fato de manter a mesma tendência sazonal desde 2005, demonstra que a prática da queima de biomassa ainda é intensa na região. O uso de fogo para manejo na área rural ainda é comum, além de haver grandes áreas queimadas de forma acidental. A deposição úmida de nitrogênio (N-org + NH4+ + NO3-) para Ribeirão Preto foi de 10,5 kg (N) ha-1 ano-1, sendo que a fração orgânica representou 33% dessa deposição, demonstrando a importância de se determinar N-org para melhor estimar os fluxos atmosféricos de deposição. A massa estimada de nitrogênio depositada pela chuva é cerca de 16% do nitrogênio aplicado por meio de fertilizantes em culturas de cana. Somando as deposições de nitrogênio pelo material particulado, pela fase gasosa, e úmida, esta última representa 71% do fluxo atmosférico de nitrogênio. Nesse contexto, a fração orgânica corresponde a 24% da deposição total, sendo que este valor ainda pode estar sendo subestimado, pois as concentrações de N-org no material particulado não foram determinadas. A simplicidade e exatidão do método aqui proposto pode facilitar a aquisição de dados de N-org na chuva de outras partes do mundo, melhorando assim o conhecimento sobre o ciclo biogeoquímico global do nitrogênio. / Nitrogen species have been intensively added to the environment since the development of Haber-Bosch process for N2 transformation to NH3, significantly altering the biogeochemical cycle of nitrogen. Once in the atmosphere, reactive nitrogen is deposited back to the Earth\'s surface by wet and dry deposition processes. The importance of taking into account the organic forms of nitrogen to estimate atmospheric nitrogen deposition by rain is already known. However, few studies evaluated this fraction due to the difficulties and uncertainties imposed by the available analytical methods. This work presents the development of a new, simple and low-cost method for the determination of organic nitrogen (N-org) in rainwater using photo-Fenton process and a homemade photo-reactor. By adding Fenton solution (50 mol L-1 Fe2+ and 2 mmol L-1 H2O2) and keeping the reaction under UV radiation for 90 min (85 °C), it was possible to obtain an average of 106 ± 8% nitrogen recovery for solutions containing 50 mol N L-1 of the model molecules: urea, serine, glycine and histidine. In the case of arginine, 90 min of radiation was sufficient to degrade solutions containing 10 mol N L-1. A commercial reactor showed to be more efficient in degradation of the tested compounds (30 min). However, with a time of 75 min, the homemade reactor achieved the same results. With 0.2 g L-1 TiO2 and 120 min of UV radiation, it was also possible to obtain satisfactory results. Nevertheless, this method had high blank values, and filtration of irradiated samples before the analysis was necessary, which increased time and cost to the analytical procedure. The developed method using photo-Fenton was applied to determine N-org in rainwater samples collected in Ribeirão Preto city (SP) from 2013 to 2017. N-org concentrations ranged from 3.5 to 195 mol N L-1 with a volume-weighted mean concentration (VWM) of 17.7 ± 1.0 mol N L-1 (n = 236). This value was higher than those reported for rainwater from different parts of the world, and this fact can be attributed to the high biomass burning in the study region. Dissolved free amino acids (AA) mean concentrations represented 15 ± 12% (n = 144) of the organic nitrogen fraction in rain, while urea concentrations were close to or below the limit of quantification of the method (0.5 mol N L-1). Considering all temporal series, initiated in 2005 at the same sampling site, the VWM concentration calculated for NH4+ ions was 22.2 ± 1.1 mol L-1 (n = 460) and for NO3- was 13.3 ± 0.6 mol L-1 (n = 466), while NO2- mean concentration was irrelevant. Significantly higher concentrations (t-test, P = 0.05) of NH4+, NO3-, N-org and AA were obtained during the harvest period (dry season) in relation to the non-harvest one (rainy season), for all evaluated years. Although manual harvesting was drastically reduced, the fact that the same seasonal trend has been maintained since 2005 demonstrates that the practice of biomass burning is still intense in the region. In rural area, using fire for land management is still common, in addition to large areas burned by unintentional fires. Nitrogen deposition (N-org + NH4+ + NO3-) in Ribeirão Preto was 10.5 kg (N) ha-1 year-1, and the organic fraction represented 33% of this deposition, demonstrating the importance of determining N-org to better estimate the atmospheric deposition fluxes. The estimated mass of nitrogen deposited by rain represents approximately 16% of the nitrogen introduced by fertilizers in sugarcane crops. Summing up the nitrogen deposition by particulate matter, by gas phase, and by rain, the latter represents 71% of the atmospheric nitrogen flux. In this context, the organic fraction corresponds to 24% of the total deposition, and this value may still be underestimated, since N-org concentrations in particulate matter were not determined. The simplicity and accuracy of the method proposed here may facilitate acquisition of N-org data in rainwater from other parts of the world, thus improving the knowledge on the global biogeochemical cycle of nitrogen.

Os fungos de decomposição branca e parda produzem enzimas para degradar os componentes da madeira, os primeiros produzem enzimas hidrolíticas e oxidativas enquanto os outros produzem principalmente enzimas hidrolíticas. A degradação de polissacarídeos e lignina por fungos de decomposição parda e branca seletiva, respectivamente, não ocorre na região imediata à hifa, e, também, não pode ser explicada unicamente por ação enzimática devido a impermeabilidade das mesmas na parede celular. Neste trabalho estudou-se o sistema degradativo não enzimático envolvendo compostos de baixa massa molar (CBMM) redutores de ferro em fungos degradadores de madeira. O fungo de decomposição parda, Wolfiporia cocos e o de decomposição branca seletiva, Perenniporia medulla-panis foram cultivados em diferentes concentrações de ferro, e a atividade redutora de Fe3+ micelial e a extracelular, assim como a produção de quelantes específicos de ferro, como derivados de ácido hidroxâmico e de catecol, foram induzidas em condição de deficiência de ferro. Os géis de SDS-PAGE dos extratos fúngicos mostraram várias proteínas negativamente reguladas por ferro em P. medulla-panis e W. cocos, principalmente para proteínas entre 10 - 30 kDa. Quando os fungos foram cultivados em diferentes fontes de carbono simples com e sem suplementação de celulose microcristalina e deficiência de ferro, produziram CBMM redutores de Fe3+, os quais tiveram a produção estimulada nos meios com celulose. Análises de eletroforese capilar dos compostos quelantes de metal extraídos dos meios que proporcionaram a maior atividade redutora (Lornitina/ celulose para P. medulla-panis e glicose/celulose para W. cocos) na presença e ausência de ferro, confirmaram que, principalmente P. medulla-panis produz compostos extracelulares que são regulados por ferro. Os CBMM purificados das frações < 5 kDa apresentaram atividade redutora de Fe3+ em pH 2,0 mesmo quando ácido oxálico foi adicionado na concentração 20 vezes maior que a concentração de Fe3+. Em pH 4,5, a atividade redutora foi detectada até uma concentração de ácido oxálico 10 vezes superior a de Fe3+. Em ambos os casos a atividade redutora foi observada quando Fe3+ estava presente na forma livre ou complexada como Fe(oxalato)+. Dentre os vários CBMM produzidos por P. medulla-panis e W. cocos aqueles com atividade redutora foram o ácido 4-hidroxi-fenilacético, 1,2-dihidroxi-3-metil-benzeno, 1,2,3-trihidroxi-benzeno e o ácido 4- hidroxi-cinâmico para W. cocos, e para P. medulla-panis os principais foram 1,2-dihidroxibenzeno e 1,2,3-trihidroxi-benzeno. Além desses compostos, ambos os fungos produziram peptídeos de baixa massa molar com atividade redutora. Os CBMM redutores de Fe3+ de P. medulla-panis (Pmp) e de W. cocos (Wc) foram utilizados na ausência e presença de Fe3+ e H2O2 (reação de Fenton mediada) para oxidar polissacarídeos e lignina in vitro. Verificou-se que os maiores níveis de oxidação foram obtidos nas reações de Fenton mediadas (Wc-Fe3+/H2O2 e Pmp-Fe3+/H2O2). A degradação da celulose por estes sistemas foi caracterizada por uma rápida e extensiva despolimerização, seguida de significativa oxidação. Análises dos monômeros de lignina liberados de conífera tratada e não tratada após 13C-TMAH termoquimólise indicaram oxidação da lignina pelos sistemas Wc-Fe3+/H2O2 e Pmp- Fe3+/H2O2, principalmente por desmetoxilação e/ou desmetilação. A ação sinérgica entre os CBMM redutores de Fe3+ e as enzimas ligninolíticas ficou evidenciada para os fungos de decomposição branca Lentinula edodes, P. medulla-panis e Trametes versicolor através da oxidação do corante Azure B. / Brown and white rot fungi produce enzymes to degrade wood. The former produce hydrolytic and oxidative enzymes while the latter produce mainly hydrolytic enzymes. The degradation of polysaccharides and lignin by brown and white-rot fungi, respectively, do not occur next to the fungal hyphae and cannot be explained only by the enzymatic action due to the small pore size of sound wood. In this work, it was studied a non-enzymatic degradative system involving low molecular weight compounds (LMWC) with Fe3+-reducing activity in wood decay fungi. The brown rot fungus Wolfiporia cocos and the selective white rot Perenniporia medulla-panis were grown under varying concentration of iron. The micelial and extracellular Fe3+-reducing activity as well as the production of specific iron chelators (catechol and hydroxamate derivatives) were induced under iron starvation. SDS-PAGE gels of cellular proteins showed several proteins negatively iron-regulated in P. medulla-panis and in W. cocos, especially for proteins of 10 - 30 kDa. When the fungi were grown with different simple carbon source with and without microcrystalline cellulose supplementation and under iron restriction, they produced LMWC with Fe3+-reducing activity, which production was stimulated in the presence of cellulose. Capillary electrophoresis analyses of metal chelating compounds extracted from the growth media that promoted the highest Fe3+-reducing activity (L-ornithine/cellulose for P. medulla-panis and glucose/cellulose for W. cocos) in the presence and absence of iron, confirmed that, especially P. medulla-panis produces extracellular compounds that are iron-regulated. LMWC purified from these media showed Fe3+-reducing activity at pH 2.0 even when oxalic acid was added up to 20 fold the iron concentration. At pH 4.5, the Fe3+-reducing activity was detected at an oxalic acid concentration up to 10 fold the iron concentration. In both cases the LMWC were capable of reducing Fe3+ only when it was in its free form or complexed with oxalate to form Fe3+-monooxalate complex (Fe(C2O4)+). Among the several LMWC produced by P. medulla-panis and W. cocos those with Fe3+-reducing capability were 4-hydroxy-phenylacetic acid, 1,2- dihydroxy-methyl-benzene, 1,2,3-trihydroxy-benzene and 4-hydroxy-cinnamic acid to W. cocos and 1,2-dihydroxy-benzene, and 1,2,3-tri-hydroxy-benzene to P. medulla-panis. Both fungi also produce low molecular weight peptides with Fe3+-reducing capability. The purified LMWC with Fe3+-reducing activity from P. medulla-panis (Pmp) and from W. cocos (Wc) were utilized in the presence and absence of Fe3+ and H2O2 (mediated Fenton reaction) to oxidize polysaccharides and lignin in vitro. The highest oxidation levels were obtained with mediated Fenton reactions (Wc-Fe3+/H2O2 e Pmp-Fe3+/H2O2). Cellulose degradation by these systems was characterized by a rapid and extensive depolymerization followed by significant oxidation. Analyses of the lignin monomers released from treated and untreated softwood after 13C-TMAH thermochemolysis indicated lignin oxidation by the Wc-Fe3+/H2O2 and Pmp-Fe3+/H2O2 systems, mainly by demethoxylation and/or demethylation. The synergistic action between LMWC with Fe3+-reducing activity and the ligninolytic enzymes was evidenced to the white rot fungi Lentinula edodes, P. medulla-panis and Trametes versicolor with Azure B oxidation assays.

Há, no Brasil, uma enorme diversidade de espécies vegetais, e um conhecimento popular de várias propriedades medicinais das mesmas. Dentre os estudos realizados com extratos de plantas, há um interesse especial na atividade antioxidante. Este trabalho, focado em atividade antioxidante, é dividido em duas partes: a primeira, utiliza a técnica de RPE para estudar a ação dos antioxidantes neutralizando os radicais livres, enquanto que a segunda utiliza a TFD para, em simulação computacional, ajudar a entender os resultados obtidos na primeira parte. Foram analisados 10 extratos vegetais: Swartzia langsdorffii, Machaerium villosum, Pterogyne nitens, Maytenus ilicifolia (casca de raiz), Pera glabrata, Aegiphyla sellowiana, Copaifera langsdorffii, Chrysophyllum inornatum, Iryanthera juruensis (folhas e sementes), Didymopanax vinosum. O estudo da atividade antioxidante com RPE utiliza dois métodos diferentes: o primeiro método mede a atividade antioxidante por meio do controle da quantidade de radicais livres, TEMPOL e DPPH, em contato com o extrato vegetal, enquanto que o segundo método utiliza o spin trap DMPO em conjunto com a reação de Fenton (Fe2+ + H2O2 => Fe3+ + HO- + HO) para analisar a ação dos extratos vegetais contra o radical hidroxila (OH?). A simulação computacional dos compostos TEMPOL, DPPH e DMPO é realizada em um método de primeiros princípios na Teoria do Funcional da Densidade, com uso de pseudopotenciais. O código utilizado é o SIESTA. As conclusões indicam que o extrato de Iryanthera juruensis, tanto de folhas quanto de sementes, exibe atividades antioxidantes bastante acentuadas, em todos os métodos utilizados. A simulação computacional aponta o TEMPOL menos reativo que o DPPH, devido a menor energia liberada em sua reação de redução. Sabendo que algumas destas espécies já são usadas popularmente por propriedades medicinais, estudos futuros para a correta identificação do agente antioxidante e seu possível uso, tanto na indústria alimentícia quanto na farmacêutica, deverão ser realizados. / There is, in Brazil, a great diversity of vegetable species, and a popular knowledge of several medicinal properties of the some of them. In studies carried out with plants? extracts, there is special interest in antioxidant activities. This work, focused in antioxidant activity, is divided in two parts: the first uses EPR technique to study the antioxidant activities neutralizing free radicals, while the second one uses DFT, in computational simulation, to understand the results obtained from the first part. Ten vegetable extracts were analyzed: Swartzia langsdorffii, Machaerium villosum, Pterogyne nitens, Maytenus ilicifolia (bark root extracts), Pera glabrata, Aegiphyla sellowiana, Copaifera langsdorffii, Chrysophyllum inornatum, Iryanthera juruensis (leaves and seeds), Didymopanax vinosum. The study with EPR uses two different methods: the first method measures the antioxidant activity by monitoring the amount of free radicals, DPPH and TEMPOL, that are in contact with the plant extract, the second method uses spin trap DMPO with Fenton reaction (Fe2+ + H2O2 => Fe3+ + HO- + HO) for the study of the plant extract antioxidant activity against the hydroxyl radical (OH?). The computational simulation of TEMPOL, DPPH and DMPO is carried out using a method of first principles within the Density Functional Theory and pseudopotentials. The code is SIESTA. The conclusions indicate that the Iryanthera juruensis extract, as of leaves as of seeds, exhibits accentuated antioxidants activities, in all of the used methods. The computational simulation indicated that the TEMPOL is less reactive than the DPPH, because the lower energy in its reduction reaction. As some of these species are already used popularly by medicinal properties, future studies for correct identification of the antioxidant compounds and its possible use, as in the food industry as in the pharmaceutical industry, should be realized.