The marked increase in surface-to-volume ratio associated with microscale devices for hemodialysis leads to problems with hemocompatibility and blood flow distribution that are more challenging to manage than those encountered at the conventional scale. In this work, stable surface modifications with pendant polyethylene oxide (PEO) chains were produced on polycarbonate microchannel and polyacrylonitrile membrane materials used in construction of microchannel hemodialyzer test articles. These coatings were evaluated in relation to protein repulsion, impact on urea permeability through the membrane, and impact on bubble retention through single-channel test articles. PEO layers were prepared by radiolytic grafting of PEO-PBD-PEO (PBD = polybutadiene) triblock copolymers to microchannel and membrane materials. Protein adsorption was detected by measurement of surface-bound enzyme activity following contact of uncoated and PEO-coated surfaces with ��-galactosidase. Protein adsorption was decreased on PEO-coated polycarbonate and polydimethyl siloxane (PDMS) materials by 80% when compared to the level recorded on uncoated materials. Protein adsorption on membrane materials was not decreased with PEO-PBD-PEO treatment; a PEI (polyethylene imide) layer exists on the AN69 ST membrane which is intended to trap heparin during membrane pre-treatment. It is still unclear how this PEI layer interacts with PEO-PBD-PEO. Neither the PEO-PBD-PEO triblocks nor the irradiation process was observed to have any effect on polyacrylonitrile membrane permeability to urea, nor did the presence of additional fibrinogen and bovine serum albumin (BSA) in the urea filtrate. The PEO-PBD-PEO treatment was not able to visibly reduce bubble retention during flow through single-channel polycarbonate test articles, however, the rough surfaces of the laser-etched polycarbonate microchannels may be causing this bubble retention. This surface treatment holds promise as a means for imparting safe, efficacious coatings to blood processing equipment that ensure good hemocompatibility and blood flow distribution, with no adverse effects on mass transfer. / Graduation date: 2013

Molecular aspects of nitrogen metabolism in vertebrates is an interesting area of physiology and evolution to explore due to the different ways in which animals excrete nitrogenous waste as they transition from an aquatic to a terrestrial lifestyle. Two main products of nitrogen metabolism in fishes are ammonia and urea. Ammonia is produced during protein catabolism and build up of ammonia is toxic. Some aquatic vertebrates convert ammonia into a less toxic compound urea via de novo synthesis through the ornithine-urea cycle (O-UC). Five enzymes are involved in the O-UC: carbamoyl phosphate synthetase (CPS), ornithine carbamoyl transferase (OCT), argininosuccinate synthetase (ASS), argininosuccinate lyase (ASL), and arginase (ARG). An accessory enzyme, glutamine synthetase (GS) also participates in the "fish-type" O-UC. Teleosts excrete ammonia passively over their gills into the aquatic environment. The teleost, Opsanus beta, has been shown to increase urea production after 48 hours of crowding. This thesis explored how crowding stress affected nitrogen metabolite levels of ammonia and urea and O-UC gene expression and enzyme activity in O. beta. Lungfishes while in an aquatic environment avoid ammonia toxicity by releasing excess ammonia across their gills, but when stranded on land they produce urea through the O-UC. Urea production via the O-UC has a metabolic cost of at least four ATP molecules. This thesis explored the response of a lungfish, Protopterus annectens, to six days of aerial exposure and re-immersion conditions by measuring concentrations of O-UC mRNA expression and enzyme activity and nitrogen metabolites ammonia and urea. CPS acts as the entry point to the O-UC and based on enzymatic studies, most aquatic vertebrates utilize one isoform of this enzyme (CPSIII) while terrestrial vertebrates utilize a different isoform of this enzyme (CPSI). Lungfishes are a particularly interesting group of air-breathing fishes, not only because of their link to the origins of tetrapods, but also because CPS I may have originated within this group. Both CPS III and CPS I have been enzymatically described within this group. This thesis uses phylogenetics to investigate how CPS nucleotide sequences in lungfishes evolved compared to other vertebrates.

Transition metals have played an important role in synthetic organic chemistry for more than a century, and offer catalytic transformations that would have been impossible with classical chemistry. One of the most useful and versatile of the transition metals is palladium, which over the years has catalyzed many important carbon-carbon forming reactions. Popular cross-coupling reactions such as the Suzuki, Stille and the Heck reaction are all catalyzed by palladium, or more correctly, by palladium in its ground state, Pd(0). Recently, interest in palladium(II)-catalyzed transformations has started to grow, partly due to the development of the vinylic substitution reaction, commonly called the oxidative Heck reaction, presented in this thesis. This Pd(II)-catalyzed, ligand-modulated reaction occurs under air at room temperature, and for the first time a general protocol employing a wide range of olefins and arylboronic acids was obtained. Ligand screening showed that the bidentate nitrogen ligand, 2,9-dimethyl-1,10-phenanthroline (dmphen), was the most suitable ligand. Dmphen is believed to facilitate regeneration of active Pd(II), increase catalytic stability and improve the regioselectivity in the reaction. A mechanistic investigation was conducted using electrospray ionization mass spectrometry (ESI-MS), making it possible to observe cationic intermediates in a productive oxidative Heck arylation. The results obtained are in agreement with the previously proposed catalytic cycle. The emerging discipline of high-speed synthesis is making contributions to society’s growing demand for new chemical entities. This inspired the development of two ultrafast, microwave-accelerated carbonylation reactions with dicobalt octacarbonyl acting both as an in situ carbon monoxide supplier and reaction mediator. A wide range of symmetrical benzophenones was produced in only 6 to 10 s, using aryl iodides as the substrate. The second carbonylation reaction provided symmetrical and unsymmetrical ureas in process times ranging from 10 s to 40 minutes using primary and secondary amines.

This thesis presents two interrelated studies that consider nutrient management and seasonal changes in recharge on agricultural lands within the context of source water protection. The research focuses first on the management of the risk to groundwater quality through the implementation of various nutrient management practices and secondly considers the dynamic nature of the transport pathway to the groundwater system associated with seasonal changes in climate and hydrology. The combined results provide insight into several of the key factors influencing the protection of groundwater sources within the agricultural landscape. Field work was completed between 2009 and 2010 on an agricultural field near the City of Woodstock, Ontario. The site is located within a source water protection area; the two-year travel time zone of the Thornton Well Field which represents the primary water supply for the City of Woodstock and which has experienced chronic increases in nitrate concentrations over the last few decades. The wells are completed in glacial overburden consisting of intermingling sand and gravel till aquifers which overly a limestone bedrock aquifer. Agricultural best or beneficial management practices (BMPs) field have been implemented and monitored since 2004. The BMPs were adopted in order to reduce nitrogen losses to the aquifer, and consisted of a reduction in nitrogen fertilizer application rates over a series of agricultural fields located near the well The first study is a one year experiment designed to compare alternative nutrient management practices for corn. Combinations of fertilizer treatments with or without a legume cover crop (red clover) were assessed. The fertilizer treatments studied were: a polymer coated urea (slow-release fertilizer) applied at planting, a conventional urea applied at planting, side-dress treatment of a solution of urea and ammonium nitrate in water containing 28% nitrogen with two different application rates applied in the early summer, and a control. The legume cover crop was incorporated in the soil in the previous fall, and acts as a slow release fertilizer as nitrogen is made available to the following crop as the plants decompose. Treatments were compared based on crop yield, overall economic return, and the potential for nitrate leaching. The potential for nitrate leaching was evaluated with bi-weekly shallow soil core during the growing season, and deep soil cores taken before planting, after harvest and the following spring. The deep cores allowed changes in nitrate storage below the rooting zone to be assessed. The results of this study highlight the importance of timing of fertilizer applications and rate of fertilizer applications. Treatments which provide a delay in the release or application of fertilizer, the polymer-coated urea, the calculator-rate side-dress and the clover cover crop, were found to be advantageous. The polymer-coated urea treatments and side-dress treatments were found to reduce leaching compared to the conventional urea treatment. Treatments with the clover cover crops were not found to reduce crop yields or increase leaching potential, and lower fertilizer costs associated to this practice were found to have a positive economic effect. Plots treated with the high-rate side-dress fertilizer application lost more nitrate to the subsurface compared to the other treatment options, and an economic disadvantage was observed as yields did not compensate for higher fertilizer costs. The study highlights the advantages of the different treatments under study, which may be used to inform policy makers and farmers in the selection of economically and environmentally sustainable nutrient management BMP options. Groundwater monitoring at the site over the years has indentified interesting recharge dynamics, particularly in the vicinity of an ephemeral stream which develops annually during spring and winter melt events in a low lying area of the study site. It was hypothesized that rapid recharge could occur beneath the stream allowing for surface water to quickly reach groundwater, posing a threat to municipal water wells. The current framework of source water protection does not take into account the potential risk posed by this type recharge event. At this field site, rapid infiltration associated with this type of event may pose a risk to drinking water quality due to the proximity of the stream to the pumping wells and the nature of the aquifer. The second study examines rapid groundwater recharge processes beneath the ephemeral stream during the course of a spring melt in 2010. The goals of the study were to quantify recharge at one location beneath the stream and to assess whether temperature variations above the water table can be used as a tracer to reasonably estimate recharge during a short live recharge event. A novel housing for the temperature sensors was designed in order to deploy and position them into gravelly materials within the vadose zone, which reduced the potential for the formation of preferential pathways and permitted the retrieval of the sensors at a later date. Field data were collected during the course of the spring melt period from a network of groundwater monitoring wells and subsurface temperature sensors. Spatial and temporal changes in groundwater geochemistry, hydraulic head and temperature were were used to characterize recharge dynamics at the field site. Recharge beneath a segment of the ephemeral stream was quantified through the numerical analysis of the field data using Hydrus 1-D, a one-dimensional numerical model designed to simulate soil water flow and heat transport in variably saturated porous media. Site specific data were used to create the model domain, provide estimates of physical parameters, and to define initial and time variable boundary conditions. Model parameters were first calibrated by simulating periods where it was expected that soils would be gravity drained with minimal soil water flow, and then further refined by simulating the period when the ephemeral stream was present. A final set of parameters was determined, and the initial gravity drained conditions were re-simulated. The model was able to reproduce field observations under different flow scenarios using the final set of parameters, suggesting that the conceptual model and final model domain representative of the actual field conditions. The successful simulation of the field data sets under the different flow scenarios also increases confidence in the uniqueness of the model results. The model estimated that 0.15 m of recharge occurred beneath the instrumented site during the period between March 9th and March 22nd of 2010 when the ephemeral stream was present. This represents approximately a third of the expected total annual recharge for this location. Regional changes in hydraulic head, groundwater temperature and groundwater chemistry provided additional insight into the dynamic nature of the recharge process during the spring meld period and further illustrated the spatial variability of the aquifers’ response to the stream. The study found that the use of temperature as a tracer provided useful and quantifiable insight into recharge phenomena. The results of this study suggest that high rates of rapid recharge occur beneath the ephemeral stream, and are spatially variable. This type of focused infiltration that occurs during the spring melt may represent a risk to municipal water quality if the infiltrating waters are carrying contaminants.

Chiral cyclic alpha azido ketones are very important compounds in organic chemistry. Because, the reduced forms of them are amino alcohols and these amino alcohols are interesting compounds for their biological activities. They have some pharmaceutical activities such as: potassium channel open up properties, treatment of central nervous system, antihypertensive properties, the agent of dopamin receptor activator, hypolipemic agent and dopamine agonist. These types of compounds have highly acidic alpha-protons, and many kinds of reactions can be performed with them. In this study, mainly, selective protonation of racemic compounds was performed with a new practical method and there are not so many examples related to deracemization in the literature. Alpha-azido derivatives of tetralone, indanone, chromanone, and thiochromanone structures are chosen as starting materials because of their importance for biological activities arising from their cyclic structures. Firstly, these &alpha / -azido compounds were synthesized according to literature. The acidic alpha-protons do not require strong bases. Their enantioselective deracemization and deracemization processes were screened by using Cinchona derivatives as organocatalysts. This screening process was monitored by chiral HPLC columns. The parameters such as catalyst loading, solvent, temperature, reaction time and additives were optimized to obtain high enantioselectivities up to 98%. In addition to deracemization reactions, Michael addition reactions were also performed by starting from &alpha / -azido chromanones. In these reactions different type of urea catalyst was used to activate the electrophilic part of trans-&beta / -nitrostyrene compound. Again by controlling the temperature, time and catalyst loading, two diastereomers were formed and the screening process was monitored by chiral HPLC columns again. The Michael products were obtained in up to 94% ee and 75% yield.

This thesis aims at developing a method of chemical aftertreatment for reduction of free formaldehyde release of a tetrakis (hydroxymethyl) phosphonium chloride (THPC) urea precondensate, ammonia cured durable flame retardant finished cotton fabric, by preventing the formation of free formaldehyde. Formaldehyde is toxic and carcinogenic. According to the worldwide standards, acceptable limit of free formaldehyde release, for the fabrics that have skin contact, is only 75 ppm (measured by water extraction method). In this research, a cotton fabric flame retardant finished in an industrial plant in Pakistan is used. Fabric is finished by the application of THPC urea precondensate and ammonia cured, oxidized and washed. After finishing, it is not aftertreated with sodium metabisulfite that is a commonly used aftertreatment method for the reduction of free formaldehyde release. Aftertreatment with sodium metabisulfite has various problems that include large number of hot washings and there is an increase in the formaldehyde release during fabric storage. If the fabric has 75 ppm of free formaldehyde, there is often an increase in free formaldehyde release during fabric storage. There is a very limited research on the aftertreatment methods and few reports of application of these aftertreatments on flame retardant fabrics have been published. In this research, two methods of aftertreatments are developed to reduce the free formaldehyde contents to 75 ppm or less. One is the aftertreatment with a combination of resorcinol 1% and diethylene glycol 4%. The other is the combination of resorcinol 1% and boric acid 6%. For both these aftertreatments, ammonium acetate 0.5% is used as a catalyst. Fabric is padded with the solution and then dried at 130̊ C for 8 minutes. After drying, fabric is rinsed with water at 40̊ C. The aftertreatment methods developed in this research have shown a long term effect in keeping the formaldehyde release below 75 ppm during fabric storage that is not available with other conventional aftertreatment methods. These aftertreatment methods have no adverse effect on the flame retardancy of the THPC ammonia cured finished fabric and the fabric is soft as compared to the original flame retardant finished fabric and to the fabric after treated with existing methods. These new developed methods have industrial application because there is no use of any solvent and there is no use of any special equipment for the aftertreatment.

This thesis presents two interrelated studies that consider nutrient management and seasonal changes in recharge on agricultural lands within the context of source water protection. The research focuses first on the management of the risk to groundwater quality through the implementation of various nutrient management practices and secondly considers the dynamic nature of the transport pathway to the groundwater system associated with seasonal changes in climate and hydrology. The combined results provide insight into several of the key factors influencing the protection of groundwater sources within the agricultural landscape. Field work was completed between 2009 and 2010 on an agricultural field near the City of Woodstock, Ontario. The site is located within a source water protection area; the two-year travel time zone of the Thornton Well Field which represents the primary water supply for the City of Woodstock and which has experienced chronic increases in nitrate concentrations over the last few decades. The wells are completed in glacial overburden consisting of intermingling sand and gravel till aquifers which overly a limestone bedrock aquifer. Agricultural best or beneficial management practices (BMPs) field have been implemented and monitored since 2004. The BMPs were adopted in order to reduce nitrogen losses to the aquifer, and consisted of a reduction in nitrogen fertilizer application rates over a series of agricultural fields located near the well The first study is a one year experiment designed to compare alternative nutrient management practices for corn. Combinations of fertilizer treatments with or without a legume cover crop (red clover) were assessed. The fertilizer treatments studied were: a polymer coated urea (slow-release fertilizer) applied at planting, a conventional urea applied at planting, side-dress treatment of a solution of urea and ammonium nitrate in water containing 28% nitrogen with two different application rates applied in the early summer, and a control. The legume cover crop was incorporated in the soil in the previous fall, and acts as a slow release fertilizer as nitrogen is made available to the following crop as the plants decompose. Treatments were compared based on crop yield, overall economic return, and the potential for nitrate leaching. The potential for nitrate leaching was evaluated with bi-weekly shallow soil core during the growing season, and deep soil cores taken before planting, after harvest and the following spring. The deep cores allowed changes in nitrate storage below the rooting zone to be assessed. The results of this study highlight the importance of timing of fertilizer applications and rate of fertilizer applications. Treatments which provide a delay in the release or application of fertilizer, the polymer-coated urea, the calculator-rate side-dress and the clover cover crop, were found to be advantageous. The polymer-coated urea treatments and side-dress treatments were found to reduce leaching compared to the conventional urea treatment. Treatments with the clover cover crops were not found to reduce crop yields or increase leaching potential, and lower fertilizer costs associated to this practice were found to have a positive economic effect. Plots treated with the high-rate side-dress fertilizer application lost more nitrate to the subsurface compared to the other treatment options, and an economic disadvantage was observed as yields did not compensate for higher fertilizer costs. The study highlights the advantages of the different treatments under study, which may be used to inform policy makers and farmers in the selection of economically and environmentally sustainable nutrient management BMP options. Groundwater monitoring at the site over the years has indentified interesting recharge dynamics, particularly in the vicinity of an ephemeral stream which develops annually during spring and winter melt events in a low lying area of the study site. It was hypothesized that rapid recharge could occur beneath the stream allowing for surface water to quickly reach groundwater, posing a threat to municipal water wells. The current framework of source water protection does not take into account the potential risk posed by this type recharge event. At this field site, rapid infiltration associated with this type of event may pose a risk to drinking water quality due to the proximity of the stream to the pumping wells and the nature of the aquifer. The second study examines rapid groundwater recharge processes beneath the ephemeral stream during the course of a spring melt in 2010. The goals of the study were to quantify recharge at one location beneath the stream and to assess whether temperature variations above the water table can be used as a tracer to reasonably estimate recharge during a short live recharge event. A novel housing for the temperature sensors was designed in order to deploy and position them into gravelly materials within the vadose zone, which reduced the potential for the formation of preferential pathways and permitted the retrieval of the sensors at a later date. Field data were collected during the course of the spring melt period from a network of groundwater monitoring wells and subsurface temperature sensors. Spatial and temporal changes in groundwater geochemistry, hydraulic head and temperature were were used to characterize recharge dynamics at the field site. Recharge beneath a segment of the ephemeral stream was quantified through the numerical analysis of the field data using Hydrus 1-D, a one-dimensional numerical model designed to simulate soil water flow and heat transport in variably saturated porous media. Site specific data were used to create the model domain, provide estimates of physical parameters, and to define initial and time variable boundary conditions. Model parameters were first calibrated by simulating periods where it was expected that soils would be gravity drained with minimal soil water flow, and then further refined by simulating the period when the ephemeral stream was present. A final set of parameters was determined, and the initial gravity drained conditions were re-simulated. The model was able to reproduce field observations under different flow scenarios using the final set of parameters, suggesting that the conceptual model and final model domain representative of the actual field conditions. The successful simulation of the field data sets under the different flow scenarios also increases confidence in the uniqueness of the model results. The model estimated that 0.15 m of recharge occurred beneath the instrumented site during the period between March 9th and March 22nd of 2010 when the ephemeral stream was present. This represents approximately a third of the expected total annual recharge for this location. Regional changes in hydraulic head, groundwater temperature and groundwater chemistry provided additional insight into the dynamic nature of the recharge process during the spring meld period and further illustrated the spatial variability of the aquifers’ response to the stream. The study found that the use of temperature as a tracer provided useful and quantifiable insight into recharge phenomena. The results of this study suggest that high rates of rapid recharge occur beneath the ephemeral stream, and are spatially variable. This type of focused infiltration that occurs during the spring melt may represent a risk to municipal water quality if the infiltrating waters are carrying contaminants.

Made available in DSpace on 2016-08-12T19:15:38Z (GMT). No. of bitstreams: 1 MauroST_DISSERT.pdf: 1583076 bytes, checksum: 21ea20c37f445bdcb3542826ae383cfd (MD5) Previous issue date: 2009-02-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The culture of the passion fruit plant-yellow it is explored commercially of north to south of Brazil, involving tropical and subtropical areas. Your cultivation is in expansion phase in reason of the great commercialization perspectives. In this context the objective of the work was to evaluate the effect of the manuring nitrogenada in the production of the yellow passion fruit plant irrigated in the conditions of Cassilandia (MS). The experimental design used was of randomized complete blocks whit 5 doses of nitrogen (0, 80, 160, 240 and 320 kg ha-1), with 4 repetitions, spaced in 3m between lines and 4m among plants; each experimental unit was constituted by 6 plants and 4 plants in the useful area. The conduction in the culture was accomplished in a wire thread to 1,8m of height of the soil. The application of the treatments was parceled out in 6 times (from 11/2006 to 05/2007), beginning 5 months after transplant of the seedlings. The crop was it accomplishes from 29/11/2006 to 17/08/2007. The increase of the manuring with nitrogen promoted an answer of behavior quadratic polinomial for the total of fruits you didn't trade; total of fruits; production commercial, no-commercial and total; commercial and no-commercial productivity; thickness of the peel; and SST. The increase of the doses of N promoted a decreasing answer for medium weight of marketable fruits; pulp revenue; number of seeds; and pH of the soil. Not being verified effect of the treatments for total of marketable fruits, weigh medium, diameter and fruit length; and pH of the pulp. The manuring with nitrogen influences in the production and the quality of the passion fruit plant-yellow, in the conditions of Cassilandia (State of Mato Grosso do Sul - Brazil), it can be applied from 116 to 173 kg ha-1 of nitrogen in covering. / A cultura do maracujazeiro amarelo é explorada comercialmente de norte a sul do Brasil, envolvendo regiões tropicais e subtropicais. Seu cultivo encontra-se em fase de expansão em razão das ótimas perspectivas de comercialização. Neste contexto o objetivo do trabalho foi avaliar o efeito da adubação nitrogenada na produção do maracujazeiro amarelo irrigado nas condições de Cassilândia (MS). Foi utilizado um experimento com delineamento em blocos casualizados ao acaso, sendo testadas 5 doses de nitrogênio (0, 80, 160, 240 e 320 kg ha-1), com 4 repetições, espaçadas em 3 m entre linhas e 4 metros entre plantas; cada unidade experimental foi constituída por 6 plantas, sendo 4 plantas a área útil. A condução da cutura foi realizada em forma de espaldeira, conduzido por um fio de arame a 1,8m de altura. A aplicação dos tratamentos foram parcelada em 6 vezes (11/2006 a 05/2007), iniciando 5 meses após o transplantio. A colheita foi realizada de 29/11/2006 a 17/08/2007. O aumento da adubação nitrogenada promoveu uma resposta de comportamento polinomial quadrática para o total de frutos; produção comercial e total; produtividade comercial; espessura da casca; o SST e pH do solo. O aumento das doses de N promoveu uma resposta decrescente para peso médio de frutos comerciáveis; rendimento de polpa e o número de sementes. Não sendo verificado efeito dos tratamentos para total de frutos comerciáveis, peso médio, diâmetro equatorial e comprimento de frutos; pH da polpa. A adubação nitrogenada influencia na produção e a qualidade do maracujazeiro amarelo , nas condições de Cassilândia (MS), pode ser aplicado de 116 a 173 kg ha-1 de nitrogênio em cobertura.

Made available in DSpace on 2016-08-12T19:18:54Z (GMT). No. of bitstreams: 1 MauroST_DISSERT.pdf: 1583076 bytes, checksum: 21ea20c37f445bdcb3542826ae383cfd (MD5) Previous issue date: 2009-02-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The culture of the passion fruit plant-yellow it is explored commercially of north to south of Brazil, involving tropical and subtropical areas. Your cultivation is in expansion phase in reason of the great commercialization perspectives. In this context the objective of the work was to evaluate the effect of the manuring nitrogenada in the production of the yellow passion fruit plant irrigated in the conditions of Cassilandia (MS). The experimental design used was of randomized complete blocks whit 5 doses of nitrogen (0, 80, 160, 240 and 320 kg ha-1), with 4 repetitions, spaced in 3m between lines and 4m among plants; each experimental unit was constituted by 6 plants and 4 plants in the useful area. The conduction in the culture was accomplished in a wire thread to 1,8m of height of the soil. The application of the treatments was parceled out in 6 times (from 11/2006 to 05/2007), beginning 5 months after transplant of the seedlings. The crop was it accomplishes from 29/11/2006 to 17/08/2007. The increase of the manuring with nitrogen promoted an answer of behavior quadratic polinomial for the total of fruits you didn't trade; total of fruits; production commercial, no-commercial and total; commercial and no-commercial productivity; thickness of the peel; and SST. The increase of the doses of N promoted a decreasing answer for medium weight of marketable fruits; pulp revenue; number of seeds; and pH of the soil. Not being verified effect of the treatments for total of marketable fruits, weigh medium, diameter and fruit length; and pH of the pulp. The manuring with nitrogen influences in the production and the quality of the passion fruit plant-yellow, in the conditions of Cassilandia (State of Mato Grosso do Sul - Brazil), it can be applied from 116 to 173 kg ha-1 of nitrogen in covering. / A cultura do maracujazeiro amarelo é explorada comercialmente de norte a sul do Brasil, envolvendo regiões tropicais e subtropicais. Seu cultivo encontra-se em fase de expansão em razão das ótimas perspectivas de comercialização. Neste contexto o objetivo do trabalho foi avaliar o efeito da adubação nitrogenada na produção do maracujazeiro amarelo irrigado nas condições de Cassilândia (MS). Foi utilizado um experimento com delineamento em blocos casualizados ao acaso, sendo testadas 5 doses de nitrogênio (0, 80, 160, 240 e 320 kg ha-1), com 4 repetições, espaçadas em 3 m entre linhas e 4 metros entre plantas; cada unidade experimental foi constituída por 6 plantas, sendo 4 plantas a área útil. A condução da cutura foi realizada em forma de espaldeira, conduzido por um fio de arame a 1,8m de altura. A aplicação dos tratamentos foram parcelada em 6 vezes (11/2006 a 05/2007), iniciando 5 meses após o transplantio. A colheita foi realizada de 29/11/2006 a 17/08/2007. O aumento da adubação nitrogenada promoveu uma resposta de comportamento polinomial quadrática para o total de frutos; produção comercial e total; produtividade comercial; espessura da casca; o SST e pH do solo. O aumento das doses de N promoveu uma resposta decrescente para peso médio de frutos comerciáveis; rendimento de polpa e o número de sementes. Não sendo verificado efeito dos tratamentos para total de frutos comerciáveis, peso médio, diâmetro equatorial e comprimento de frutos; pH da polpa. A adubação nitrogenada influencia na produção e a qualidade do maracujazeiro amarelo , nas condições de Cassilândia (MS), pode ser aplicado de 116 a 173 kg ha-1 de nitrogênio em cobertura.

Título de: Químico Ambiental / El contenido hídrico afecta la actividad ureásica y nitrificante en los suelos, por ende influye en los cambios de pH y potencial de óxido reducción. Dentro de las etapas del ciclo del nitrógeno en el suelo, la degradación de urea corresponde a la mineralización de nitrógeno orgánico mediante la actividad de la enzima ureasa de origen microbiano y sus principales productos de degradación son amonio (NH4 +) y posteriormente nitrato (NO3 -). En este trabajo se estudió el efecto de la capacidad de retención de agua (CRA) sobre las curvas de saturación de ureasa y las curvas de progreso de amonio y nitrato en condiciones de saturación por sustrato mediante ensayos con microcosmos con dos suelos de la Zona Central de Chile que difieren en su contenido de carbono orgánico (CO): suelo de la localidad Alhué (Región del Libertador General Bernardo O’Higgins) con bajo CO y suelo del Campus Antumapu (Región Metropolitana) con alto CO. Se construyeron microcosmos al 60 y 100 % de la CRA de cada suelo y se incubaron con distintas concentraciones de urea hasta por 24 horas para determinar la concentración de saturación de la enzima. Para la curva de progreso se incubaron los microcosmos en condiciones de saturación por sustrato en las mismas condiciones anteriores por 16 días. Para el análisis estadístico se utilizó el coeficiente de Correlación de Pearson y Análisis de varianza (ANOVA) de dos vías, con intervalos de confianza superiores al 95 %. Los resultados de las curvas de saturación de ureasa mostraron que en ambos suelos al 100 % de la CRA disminuye la velocidad máxima (Vmáx) y la concentración de semisaturación ([S]0,5). Esto se explica porque a una mayor CRA, la menor concentración de O2 limita los procesos metabólicos de los microorganismos capaces de degradar urea (aeróbicos). La actividad ureásica es mayor en el suelo Antumapu debido a que un mayor contenido de CO se asocia a una mayor capacidad para retener microorganismos capaces de degradar urea. De acuerdo al ANOVA de dos vías hay diferencias estadísticamente significativas entre las curvas de saturación para ambos suelos. En el suelo Alhué el factor tratamiento (CRA) fue el causante de la mayor parte de la varianza total (43,73 %) junto con el factor concentración (43,01 %), mientras que en el caso del suelo Antumapu la mayor parte de la varianza total proviene del factor concentración (51,37 %), seguido del factor tratamiento (35, 41 %). En las curvas de progreso se evaluó el efecto de la CRA sobre los parámetros edáficos del suelo (potencial de óxido reducción, pH, contenido de amonio, contenido de nitrato). El ANOVA de dos vías muestra que el factor tiempo dio cuenta de la mayor parte de la varianza total en el x potencial de óxido reducción (67,14 y 96,45 % para Antumapu y Alhué respectivamente), pH (91,34 y 96,57 %), contenido de amonio (94,41 y 97,95 %) y contenido de nitrato (69,03 y 87,10 %). Respecto a las curvas de progreso del contenido de amonio, hubo diferencias estadísticamente significativas para Antumapu, a diferencia de los factores tratamiento e interacción en Alhué. En cuanto a la actividad nitrificante, esta fue baja comparada a la ureásica, probablemente a causa de los efectos inhibitorios de la concentración de amonio junto al alto pH del suelo. Además, los resultados del ANOVA de dos vías indican que los factores tratamiento (14,08 y 1,70%, para Antumapu y Alhué respectivamente) e interacción (15,80 y 10,34 %) tuvieron mayor aporte a la varianza total comparado a lo ocurrido con el contenido de amonio. Las bacterias oxidadoras de amonio y las bacterias oxidadoras de nitrito son estrictamente aeróbicas, por lo que es esperable que sean susceptibles a los tratamientos al 100 % de la CRA, debido a una menor concentración de O2 disponible y su difusión más lenta. En conclusión, el aumento de la actividad ureásica se relaciona principalmente con un mayor contenido de carbono orgánico del suelo y se favorece al 60 % de la CRA. En el caso de la actividad nitrificante, está fuertemente regulada por el efecto combinado del potencial de óxido reducción y pH, junto con el contenido de amonio. No hay claridad respecto al efecto del tratamiento en cada suelo. / The hydric content affects the urease and nitrifying activity in soils, therefore it influences changes in pH and oxidation-reduction potencial. In the steps of the nitrogen cycle in soils, urea degradation corresponds to the mineralization of organic nitrogen through the activity of the urease enzyme of microbial origin and its main degradation products, ammonium (NH4 +) and nitrate (NO3 -). In this work it was studied the effect of water holding capacity (WHC) on urease saturation curves and ammonium and nitrate content progress curves in substrate saturation conditions using microcosms with two soils from the Central Zone of Chile that differ in their organic carbon content (OC): Alhué soil (Libertador General Bernardo O’Higgins region) with low OC and Campus Antumapu soil (Metropolitana region) with high OC. Microcosms were made with 60 and 100% WHC for each soil and they were incubated with different urea concentrations up to 24 hours to establish the enzyme saturation concentration. For the progress curve, microcosms were incubated in substrate saturation conditions at the same previous conditions for 16 hours. Statistical analysis included Pearson correlation coeficient and two way Analysis of Variance (ANOVA), with confidence interval higher than 95 %. Urease saturation curve results show that both soils at 100% WHC decreasing their maximal velocity (Vmáx) and semi-saturation concentration ([S]0,5). This is explained because at a higher WHC, the lower concentration of O2 limits metabolic processes of microorganisms able to degrade urea (aerobic). The urease activity is higher in Antumapu soil, due to a higher OC that it is associated to a higher capacity to retain microorganisms capable to degrade urea. According to the two-way ANOVA there are statistically significant differences between saturation curves in both soils. In Alhue soil the treatment factor (WHC) was the cause of the major part of total variance (43.73%) together with the concentration factor (43.01%), while in Antumapu soil the major part of total variance comes from concentration factor (51.37%), followed by treatment factor (35.41%). In progress curves was evaluated the effect of WHC on edaphic parameters of soils (oxidation-reduction potential, pH, ammonium content, nitrate content). The two-way ANOVA shows that time factor gave account for the most of total variance on the oxidation-reduction potential (67.14 and 96.45 % for Antumapu and Alhué respectively), pH (91.34 and 96.57 %), ammonium content (94.41 and 97.95 %) and nitrate content (69.03 and 87.10 %). xii According the ammonium content in progress curves, there are statistically significant differences for Antumapu soil, unlike the treatment and interaction factors in Alhué. The nitrifying activity was lower than ureasic, probably due to ammonium content inhibition effect and a high soil pH. In addition to, the two-way ANOVA shows that treatment factor (14,08 y 1,70%, Antumapu and Alhué respectively) and interaction (15,80 and 10,34 %) had major contribution to total variance than in ammonium content. The ammonium oxidizing bacteria and nitrite oxidizing bacteria (responsible of nitrifying activity) are obligated aerobioc, so it’s expected that shows a sensitive behavior at 100 % WHC traeatments, due to lower O2 concentration and slower diffusion. In conclusion, an increase in urease activity it’s related to a higher OC content principally and it’s favored at 60 WHC treatments. The nitrifying activity is highly regulated by the combinated effect of oxidation reduction potential-pH, together with the ammonium content. There isn’t a clear answer to the WHC retention effect in treated soils. / 08/2019