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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Determination of organic phosphorus in soil samples by capillary zone electrophoresis coupled to electrospray ionization mass spectrometry

Giannakoudi, Theodora January 2020 (has links)
Chemical substances that are either produced by nature or by humankind have a consequence on the environment when they are accumulated to a great extent. One of nature’s major problem is that of the eutrophication of surface waters, which is caused by inorganic and organic phosphorus compounds and, in particular, from a group known as Inositol Phosphates. There are six different forms of these inositols and are commonly found in soil and sediment samples. The conducted project was aimed to develop an analytical method that could efficiently analyze and separate all six with repeatable results. As such, soil samples were collected two times from two forest locations and two crop field locations. The first time the soil samples were left overnight to dry in a drying oven while on the second time, the samples left to dry at room temperature. When the samples were considered dry enough, they processed to reach grain size and extracted with a mixture of NaOH and Titriplex® III. The extracted soil samples, the standard solutions containing inositols, and the spiked extracted soil samples with inositol solution were all analyzed with an instrumental combination of a Capillary Electrophoresis instrument coupled manually to an Electrospray mass spectrometer, where the first was operated at reversed mode and the second at negative mode. To achieve the best feasible separation, several background electrolyte solutions were created along with a large number of sheath liquids regulated by an LC pump, two Capillary Electrophoresis methods, and twenty-five distinct MS methods, all tested through extensive screening to obtain the best possible combination of parameters. Out of the obtained results from the runs, four background electrolyte solutions, two MS methods, one sheath liquid controlled by one specific flow rate, and one Capillary Electrophoresis method exhibited promising potentials with a satisfying outcome. However, the intense pulsation of the spray cone observed for many of the runs, the manual protrusion of the Capillary Electrophoresis fused silica capillary, and some random errors, the repeatability of the method is called into question.
12

Significance of soil organic phosphorus for the maintenance of tropical rain forest ecosystems / 熱帯降雨林生態系維持における土壌有機態リンの重要性

Yokoyama, Daiki 23 January 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21470号 / 農博第2313号 / 新制||農||1064(附属図書館) / 学位論文||H31||N5165(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 北山 兼弘, 教授 本田 与一, 教授 舟川 晋也 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM
13

Organic Phosphorus Compounds in Aquatic Sediments : Analysis, Abundance and Effects

Ahlgren, Joakim January 2006 (has links)
<p>Phosphorus (P) is often the limiting nutrient in lacustrine and brackish eco-systems, and enhanced input of P into an aquatic system might therefore negatively impact the environment. Because modern waste water manage-ment have reduced external P input to surface waters, internal P loading from the sediment has become one of the main P sources to aquatic ecosys-tems, in which relatively unknown organic P compounds seem to be more active in P recycling than previously thought.</p><p>This thesis focus is on improving analysis methods for organic P com-pounds in lacustrine and brackish sediments, as well as determining which of these compounds might be degraded, mobilized and subsequently recycled to the water column and on what temporal scale this occur. In both lacustrine and brackish environments, the most labile P compound was pyrophosphate, followed by different phosphate diesters. Phosphate monoesters were the least labile organic P compounds and degraded the slowest with sediment depth. In regulated lakes, it was shown that pyrophosphate and polyphos-phate compound groups were most related to lake trophic status, thus indi-cating their involvement in P cycling. This thesis also indicates faster P turn-over in sediment from the brackish environment compared to sediment from the lacustrine environment. </p><p>A comparison of organic P extraction procedures showed that pre-extraction with EDTA, and NaOH as main extractant, was most efficient for total P extraction. Using buffered sodium dithionite (BD) as a pre-extractant and NaOH as main extractant was most efficient for extracting the presuma-bly most labile organic P compound groups, pyrophosphate and polyphos-phate. Furthermore, it was determined that organic P compounds associated with humic substances were more recalcitrant than other P compounds, that the BD step used in traditional P fractionation might extract phosphate monoesters, and that NMR is a statistically valid method for quantification of organic P compounds in sediment extracts.</p>
14

Organic Phosphorus Compounds in Aquatic Sediments : Towards Molecular Identification with Mass Spectrometry

De Brabandere, Heidi January 2008 (has links)
Phosphorus (P) regulates trophic status in most aquatic systems. However, only bioavailable P contributes to primary production. In most lakes and shallow seas, mineralisation of sediment P into its bioavailable form and its release to the water column is important for maintaining primary production. Sediment organic P forms a substantial proportion of this P to be mineralised and can originate from different sources on land (farmland, forests, etc.) or from primary production in the lake. These organic P forms can thus be expected to have differing composition, degradability and recyclable P content. Knowledge of the chemical structure of sediment organic P compounds is scarce, mainly due to lack of appropriate analytical techniques. The commonly used 31P-nuclear magnetic resonance (31P-NMR) technique, only identifies P binding groups, so a mass spectrometric (MS) analysis method was developed that allows individual sediment organic P compounds to be identified. EDTA as pre-extractant resulted in the highest P yield in subsequent NaOH extraction. Extracted organic P compound groups were identified using 31P-NMR. For identification of specific P compounds with MS, a sample preparation method prior to electrospray tandem mass spectrometry (ESI-MS/MS) analysis was developed. Liquid chromatography (LC) with porous graphitic carbon prior to ESI-MS/MS enhanced sensitivity and selectivity, enabling several of the ions detected to be identified as nucleotides. 31P-NMR analysis showed P monoesters to be the most stabile P compounds throughout a lake sediment profile. The developed LC-ESI-MS/MS analysis method revealed that some monoester-P (nucleotides) were labile, while other P compounds increased in concentration with Baltic Sea sediment depth and were therefore considered stabile. Differences in patterns of P compounds detected were also shown depending on catchment characteristics in relation to Baltic Sea sediment age. For cost-effective management of eutrophication, knowledge of the sources of degradable organic P forms, contributing to internal loading, is needed. This thesis showed the developed LC-ESI-MS/MS analysis method to be a powerful analytical tool for this purpose.
15

Distribution of Dissolved and Particulate Organic Carbon, Nitrogen and Phosphorus in the South China Sea and the Taiwan Strait

Liu, Ching-Lin 24 July 2001 (has links)
Abstract The South China Sea (SCS) is the largest marginal sea in the world and connects with the East China Sea (ECS) through the Taiwan Strait (TS). This study investigates the distribution and biogeochemical behavior of both particulate and dissolved organic matter in the SCS and the TS based on samples collected on several cruises of the R/V Ocean Researchers I and III. Dissolved inorganic nitrogen and phosphorus (DIN and DIP), particulate organic carbon and nitrogen (POC and PON) as well as dissolved organic nitrogen and phosphorus (DON and DOP) concentrations were determined. Concentrations of DON and DOP in the SCS are in the range of 1.2-9.9 mMN and 0.04-0.21 mMP, respectively. The surface DON concentration is the highest in the northern SCS, whereas it is the lowest in the southern part. The DOP does not show a similar trend. DON and DOP concentrations all decrease with depth but increase slightly near the bottom, perhaps on account of sediment resuspension. Because of the preferential degradation of DOP over DON, the maximum concentration of DOP appears at a shallower depth than that of DON. Approximately 11 % and 2 % of DIN and DIP respectively are attributed to the degradation of DON and DOP above 500 m in the SCS. Concentrations of POC and PON in the SCS are in the range of 1.06-2.84 mMC and 0.07-0.36 mMN, respectively. The distributions of POC and PON show similar patterns with a correlation coefficient of 0.97. The concentrations of these are the highest at the surface layer, decrease with depth, but then increase slightly near the bottom, perhaps again because of resuspension of the bottom sediments. The ratio of PON/POC is 0.138 in the euphotic zone, a value close to the Redfield ratio of 0.15. In the TS and the adjacent coastal zones, the effect of terrestrial input is obvious and results in higher POC, PON, DON and DOP nearshore. Ranges of these concentrations are 0.06-59.6 mMN, 0.01-1.29 mMP, 3.80-57.1 mMC and 0.19-3.4 mMN, respectively. There was an attempt to use the one-dimensional diffusion-advection model to estimate the DIN and DIP production rates and the DON and DOP consumption rates over the depth range of 900-2500 m. These values are, respectively, 0.036, 0.006, 0.021 and 0.002 mmol/kg/yr.
16

Organic Phosphorus Compounds in Aquatic Sediments : Analysis, Abundance and Effects

Ahlgren, Joakim January 2006 (has links)
Phosphorus (P) is often the limiting nutrient in lacustrine and brackish eco-systems, and enhanced input of P into an aquatic system might therefore negatively impact the environment. Because modern waste water manage-ment have reduced external P input to surface waters, internal P loading from the sediment has become one of the main P sources to aquatic ecosys-tems, in which relatively unknown organic P compounds seem to be more active in P recycling than previously thought. This thesis focus is on improving analysis methods for organic P com-pounds in lacustrine and brackish sediments, as well as determining which of these compounds might be degraded, mobilized and subsequently recycled to the water column and on what temporal scale this occur. In both lacustrine and brackish environments, the most labile P compound was pyrophosphate, followed by different phosphate diesters. Phosphate monoesters were the least labile organic P compounds and degraded the slowest with sediment depth. In regulated lakes, it was shown that pyrophosphate and polyphos-phate compound groups were most related to lake trophic status, thus indi-cating their involvement in P cycling. This thesis also indicates faster P turn-over in sediment from the brackish environment compared to sediment from the lacustrine environment. A comparison of organic P extraction procedures showed that pre-extraction with EDTA, and NaOH as main extractant, was most efficient for total P extraction. Using buffered sodium dithionite (BD) as a pre-extractant and NaOH as main extractant was most efficient for extracting the presuma-bly most labile organic P compound groups, pyrophosphate and polyphos-phate. Furthermore, it was determined that organic P compounds associated with humic substances were more recalcitrant than other P compounds, that the BD step used in traditional P fractionation might extract phosphate monoesters, and that NMR is a statistically valid method for quantification of organic P compounds in sediment extracts.
17

Comparação da marcação de diversos fosfonatos: MDP, EDTMP e clodronato com sup(188)Re / Comparison of labeling various phosphonates: MDP, EDTMP and clodronate with sup(188)Re

BARBEZAN, ANGELICA B. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:35:19Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:55Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
18

Comparação da marcação de diversos fosfonatos: MDP, EDTMP e clodronato com sup(188)Re / Comparison of labeling various phosphonates: MDP, EDTMP and clodronate with sup(188)Re

BARBEZAN, ANGELICA B. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:35:19Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:55Z (GMT). No. of bitstreams: 0 / A grande aplicação dos radiofármacos está em medicina nuclear diagnóstica representando 95% dos procedimentos realizados, porém, nos últimos anos, tem crescido consideravelmente a sua aplicação em procedimentos terapêuticos. Os radionuclídeos que emitem particulas ionizantes (&alpha;, &beta; e elétrons Auger) são indicados para tratamento de tumores. Tumores malignos são responsáveis por aproximadamente 12% dos óbitos e representam a terceira causa de mortalidade no Brasil. O 188Re é um dos mais atrativos radioisótopos para uma variedade de aplicações terapêuticas em medicina nuclear, oncologia e intervenções cardiológicas, é totalmente favorável e conveniente pelo fato de que ele é livre de carregador e pode ser obtido de forma econômica na forma de um gerador de 188W/188Re, além de possuir uma meia-vida fisica de 16,9 horas e 100% de emissão de radiação &beta;-. A partir da década de 2000 vêm sendo realizadas diversas investigações envolvendo marcações de moléculas com 188Re. Os tumores metastáticos são a forma mais comum de malignidade esquelética. Em casos metastáticos os principais objetivos do tratamento são a prevenção de fraturas patológicas e promover a sobrevida com o máximo de preservação de função permitindo que o paciente mantenha o máximo possível de mobilidade e controle da dor. O objetivo deste trabalho foi realizar a comparação das marcações de diversos fosfonatos (Metileno disfofonato de Sódio MDP, Ácido Etilenodiaminotetrametilenofosfônico EDTMP, e do diclorometilenobifosfonato de sódio - Clodronato) com 188Re para terapia de metastáses ósseas. Fosfonatos são inibidores da reabsorção óssea osteoclástica e são efetivos neste tratamento. As marcações do MDP, EDTMP e Clodronato com 188Re foram otimizadas utilizando como agente redutor o cloreto estanoso (SnCl2 2H2O) e como agente estabilizante o ácido ascórbico. As variáveis estudadas foram massa do ligante, massa do SnCl2.2H2O, massa do ácido ascórbico, tempo, pH e temperatura da reação. Os resultados mostraram que se obteve um excelente rendimento de marcação de 98% para o 188Re-MDP, de 83% para o 188Re-EDTMP e 85% para o 188Re-Clodronato. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
19

Role of mycorrhizae in rhizosphere processes and phosphorus dynamics

Nall, Victoria Unknown Date (has links)
The increased soil organic phosphorus (P) mineralization observed under trees compared to pasture has been attributed to the contrasting mycorrhizal associations of the two systems but to date, little work has been conducted comparing P dynamics under different tree species with contrasting mycorrhizal associations. This study investigated rhizosphere P dynamics and P acquisition of three tree species with contrasting mycorrhizal associations (ectomycorrhizal Pinus radiata, arbuscular mycorrhizal Cupressus macrocarpa and tripartite Ecualyptus nitens) using a combination of field and controlled environment studies. Short-term field studies revealed greater acid phosphomonoesterase activity and therefore greater potential organic P mineralization under radiata pine and eucalypt compared with macrocarpa, which correlated with ectomycorrhizal colonization. Related field work revealed that the presence of pasture understory and litter had a significant impact on P dynamics. Pasture acts to increase phosphatase activity and microbial activity within the soil but with a litter layer, the increased activities are mainly above the soil in the overlying litter. A glasshouse study investigated the separate influence of mycorrhizal hyphae and roots and results showed that ectomycorrhizal fungi associated with radiata pine and eucalypt stimulated microbial activity and increased rhizosphere phosphatase activity with a concomitant decline in soil organic P. Macrocarpa and eucalypt roots exuded higher concentrations of low molecular weight organic anions compared with radiata pine which stimulated microbial activity, increased rhizosphere phosphatase activity and decreased soil organic P. A series of experiments were then conducted to further investigate the precise role of mycorrhizae in P dynamics and results showed that ectomycorrhizal colonization increased rhizosphere acid phosphomonoesterase to a greater extent than arbuscular mycorrhizae. Fluorescent staining revealed that the mycorrhizae associated with all three species had similar phosphatase production capacities. The ability of the three species to utilize organic P was investigated in two exhaustive pot experiments. Radiata pine was shown to be the best adapted to utilize organic P, especially in soils with high relative organic P contents. Eucalypt appeared to enhance soil organic P mineralization but did not take up the released inorganic P, while macrocarpa caused limited organic P mineralization compared with radiata pine and eucalypt. This work shows that ectomycorrhizal trees are best adapted to utilize organic P through increased rhizosphere phosphatase activity and stimulated microbial activity. Root exudation of LMWOAs is of higher relative importance to arbuscular mycorrhizal trees to increase microbial activity and consequently phosphatase activities when fewer hyphae are in the rhizosphere are present to produce them.
20

Efeito do butafosfan no metabolismo de vacas leiteiras saudáveis ou com mastite clínica / Effects the butaphosphan on the metabolism of healthy dairy cows with clinical mastitis

Tabeleão, Vinicius Coitinho 28 February 2014 (has links)
Made available in DSpace on 2014-08-20T13:32:50Z (GMT). No. of bitstreams: 1 tese_vinicius_coitinho_tabeleao.pdf: 864855 bytes, checksum: 84b7f4f2dc9f4bc7025094cdcd06be5f (MD5) Previous issue date: 2014-02-28 / Dairy cows are expected to perform maximum of their productive capacity, especially during the transition period (three weeks before and up to three weeks after calving). This period is characterized by intense changes in metabolism which cause a negative energy balance. This fact generates a period of typical weight loss, which has been correlated with insulin resistance, once the available glucose is destined for lactose synthesis, which in turn is responsible, in part, for milk production levels. Moreover, during lactation there are several managements that impairs animals health. If not executed properly, can cause trauma and predisposition for infections, especially of the mammary gland, because this gland is heavily manipulated and has contact with potentially infectious agents. From a entrance doorway, these agents can infect the gland and cause mastitis, which may be clinical (with clinical signs) or subclinical (without clinical signs). In situations of metabolic disorders or in cases of mastitis, the milk production may be affected. Therefore, there is a constant search for technologies that can minimize these disorders and assist the production systems. Our objective was to investigate the effects of combining butaphosphan and cyanocobalamin on the glycemic metabolism in healthy dairy cows in the postpartum period and their effects on the mammary gland recovery in dairy cows after clinical mastitis treatment. Thus, our study was stratified into two assumptions: 1) the use of the association of butaphosphan and cyanocobalamin enhances peripheral insulin resistance in dairy cows, providing greater amounts of glucose for milk production, 2) the supplementation with butaphosphan and cyanocobalamin facilitates mammary gland recovery in dairy cows affected by mastitis. In experiment 1, animals receiving repeated doses of butaphosphan and cyanocobalamin had greater weight loss and increased (P<0.05) of the activities of the enzymes aspartate aminotransferase and creatine kinase. Moreover, at end of treatment had an increase (P<0.05) in glucose concentration in treated animals when compared to the beginning of study. In experiment 2, the comparative analyzes between mild and moderate mastitis did not differ (P>0.05) in any parameters. The animals treated with butaphosphan and cyanocobalamin had lower (P<0.05) somatic cell count after the third application. However, the concentrations of glucose, albumin, TPP, NEFA and the chemical and physical components of milk did not differ (P>0.05) among groups. In concusion, the combination of butaphosphan and cyanocobalamin shows promising results as a source of nutrient that allows intensify physiological reactions mainly dependent phosphorylation. / As vacas leiteiras são desafiadas a desempenhar o máximo da sua capacidade produtiva, principalmente, durante o período de transição (três semanas anteriores e três semanas posteriores ao parto). Este período é caracterizado por intensas mudanças no metabolismo que causam um balanço energético negativo. Este fato gera uma perda de peso característica do período, que tem sido correlacionada com a resistência periférica à insulina, haja vista, que a glicose disponível esta sendo destinada para síntese de lactose, que por sua vez é responsável, parcialmente, pelo volume de leite produzido. Além disso, durante a lactação há vários manejos que podem oferecer risco à saúde dos animais, caso não sejam executados adequadamente, causando traumas e predispondo o animal a infecções, especialmente, da glândula mamária, já que ela é intensamente manipulada e tem contato com vários agentes potencialmente infecciosos. A partir de uma porta de entrada estes agentes podem infectar a glândula causando a mastite, que pode se apresentar na forma clínica (com presença de sinais clínicos), ou subclínica (sem sinais clínicos). Nas situações de desequilíbrio metabólico, ou em casos de mastite, a produção de leite pode ser prejudicada. Diante disso, há uma busca constante por tecnologias que possam minimizar estes transtornos e auxiliar os sistema de produção. Nosso objetivo foi verificar o efeito da associação de butafosfan e cianocobalamina sobre o metabolismo glicêmico de vacas leiteiras saudáveis no período pós-parto, além dos seus efeitos sobre a recuperação da glândula mamária em vacas leiteiras após o tratamento de mastite clínica. Para tanto, nosso estudo foi estratificado em dois trabalhos com as seguintes hipóteses: 1) a utilização da associação de butafosfan e cianocobalamina pode intensificar a resistência à insulina periférica, disponibilizando maior quantidade de glicose para a produção de leite em vacas leiteiras; 2) a suplementação da associação de butafosfan e cianocobalamina pode auxiliar na recuperação da glândula mamária de vacas leiteiras, após o tratamento da mastite clínica. No experimento 1, os animais que receberam sucessivas doses de butafosfan e cianocobalamina tiveram maior perda de peso e aumento (P<0,05) das atividades das enzimas aspartato amino transferase e creatinoquinase. Além disso, ao final do tratamento houve aumento (P<0,05) dos níveis glicêmicos nos animais tratados, quando comparados ao inicio. No experimento 2, as análises comparativas entre as mastites, leve e moderada, não diferiram em nenhum dos parâmetros (P>0,05). Os animais tratados com butafosfan e cianocobalamina apresentaram menor (P<0,05) contagem de células somáticas após a terceira aplicação. Entretanto, os níveis de glicose, albumina, PPT, AGNES e os componentes químicos e físicos do leite não diferiram (P>0,05) entre os grupos. Nessas condições de estudo, podemos concluir que a associação de butafosfan e cianocobalamina apresenta resultados promissores como fonte de nutriente que permite intensificar as reações fisiológicas, principalmente, as dependentes de fosforilação.

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