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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

Avaliação do potencial alelopático de raízes de capim annoni-2 (Eragrostis plana Nees) e estudo fitoquímico

Silva, Mayara Gobetti Fernandes da 13 August 2014 (has links)
CAPES / O Capim Annoni-2 (Eragrostis plana Nees), considerado uma planta daninha invasora e de difícil erradicação, tem a capacidade de dominar o meio em que se encontra, sobrepondo-se a espécies nativas e agroeconômicas. Parte desta capacidade está relacionada a efeitos alelopáticos causados por aleloquímicos liberados por esta espécie. Assim, a identificação desses aleloquímicos pode ser uma boa alternativa para produção de bio-herbicidas. Neste estudo, determinou-se o potencial alelopático de extratos brutos de éter de petróleo, acetato de etila e metanol provenientes da raíz de E. plana Nees coletadas no verão na área experimental do curso de Agronomia da UTFPR - câmpus Pato Branco, como também um estudo fitoquímico para elucidação estrutural de possíveis aleloquímicos. O potencial alelopático foi avaliado a partir de bioensaios de germinação e crescimento de radícula e hipocótilo, utilizando-se duas espécies receptoras (Ipomoea grandifolia e Euphorbia hetetophylla) e três concentrações dos extratos brutos (200, 400 e 600 ppm). Como resultados observou-se que os extratos brutos de éter de petróleo e acetato de etila atuam principalmente na cinética do processo de germinação, retardando-o, enquanto que o extrato bruto de metanol atuou, sobretudo na diminuição da germinação, inibindo 75,4% em comparação com o branco (água destilada), causando até deformidades e mortes de plântulas, estes dados para a espécie receptora E. heterophylla, a mais afetada. Quanto ao bioensaio de crescimento de hipocótilo e radícula, o extrato bruto de metanol foi o menos eficaz, destacando-se o extrato bruto de éter de petróleo a 600 ppm contra a espécie receptora I. grandifolia, causando uma diminuição no crescimento da radícula e hipocótilo de 66,3% e 65,5%, respectivamente, e o extrato bruto de acetato de etila também a 600 ppm contra a espécie receptora E. heterophylla, causou uma diminuição de 63,6% e 72% do comprimento do hipocótilo e radícula, respectivamente, ambos em comparação com seus respectivos brancos (água destilada). Através do estudo fitoquímico foi proposta a estrutura de um diterpeno, por meio do fracionamento e purificação do extrato bruto de éter de petróleo, e um composto, cuja estrutura não foi ainda completamente elucidada, este a partir do extrato bruto de metanol. Os efeitos alelopáticos apresentados pelas raízes do Capim Annoni-2, foram bastante efetivos, podendo estes serem atribuídos as substâncias fitotóxicas isoladas nesse estudo. / The Grass Annoni-2 (Eragrostis plana Nees), considered a noxious invasive and difficult to eradicate plant has the capacity to dominate the environment they are in, superseding Agrieconomic and native species. Part of this ability is related to allelopathic effects caused by allelochemicals released by this species. Thus, the identification of these allelochemicals can be a good alternative for the production of bio-herbicides. In this study, we determined the allelopathic potential of crude extracts of petroleum ether, ethyl acetate and methanol from the root of E. plana Nees collected in the summer in the experimental area of the course of Agronomy UTFPR - Pato Branco campus, as well as a phytochemical study for structural elucidation of potential allelochemicals. The allelopathic potential was assessed from bioassays of germination and growth of radicle and hypocotyl, using two receptor species (Ipomoea grandifolia and Euphorbia hetetophylla) and three concentrations of crude extracts (200, 400 and 600 ppm). As a result it was found that crude extracts of petroleum ether and ethyl acetate act mainly on the kinetics of the germination process by slowing it, while the crude methanol extract worked, especially in reducing the germination inhibiting 75.4% in comparison with blank (distilled water), causing deformities, and even death of seedlings these data to the recipient E. heterophylla, most affected. Regarding the growth bioassay hypocotyl and radicle, crude methanol extract was the least effective, highlighting the crude extract of petroleum ether at 600 ppm against receiving I. grandifolia species, causing a decrease in the growth of radicle and hypocotyl 66.3% and 65.5%, respectively, and the crude ethyl acetate extract also receiving 600 ppm against E. heterophylla caused a decrease of 63.6% and 72% of the length of the hypocotyl and radicle respectively, both compared with their white (distilled water). Through phytochemical study was proposed structure of a diterpene, through the fractionation and purification of the crude extract of petroleum ether, and a compound whose structure has not been fully elucidated, this from crude methanol extract. The allelopathic effects shown by the roots of the grass Annoni-2, were quite effective, these can be attributed to the isolated phytotoxic substances in this study.
12

Avaliação do potencial alelopático de raízes de capim annoni-2 (Eragrostis plana Nees) e estudo fitoquímico

Silva, Mayara Gobetti Fernandes da 13 August 2014 (has links)
CAPES / O Capim Annoni-2 (Eragrostis plana Nees), considerado uma planta daninha invasora e de difícil erradicação, tem a capacidade de dominar o meio em que se encontra, sobrepondo-se a espécies nativas e agroeconômicas. Parte desta capacidade está relacionada a efeitos alelopáticos causados por aleloquímicos liberados por esta espécie. Assim, a identificação desses aleloquímicos pode ser uma boa alternativa para produção de bio-herbicidas. Neste estudo, determinou-se o potencial alelopático de extratos brutos de éter de petróleo, acetato de etila e metanol provenientes da raíz de E. plana Nees coletadas no verão na área experimental do curso de Agronomia da UTFPR - câmpus Pato Branco, como também um estudo fitoquímico para elucidação estrutural de possíveis aleloquímicos. O potencial alelopático foi avaliado a partir de bioensaios de germinação e crescimento de radícula e hipocótilo, utilizando-se duas espécies receptoras (Ipomoea grandifolia e Euphorbia hetetophylla) e três concentrações dos extratos brutos (200, 400 e 600 ppm). Como resultados observou-se que os extratos brutos de éter de petróleo e acetato de etila atuam principalmente na cinética do processo de germinação, retardando-o, enquanto que o extrato bruto de metanol atuou, sobretudo na diminuição da germinação, inibindo 75,4% em comparação com o branco (água destilada), causando até deformidades e mortes de plântulas, estes dados para a espécie receptora E. heterophylla, a mais afetada. Quanto ao bioensaio de crescimento de hipocótilo e radícula, o extrato bruto de metanol foi o menos eficaz, destacando-se o extrato bruto de éter de petróleo a 600 ppm contra a espécie receptora I. grandifolia, causando uma diminuição no crescimento da radícula e hipocótilo de 66,3% e 65,5%, respectivamente, e o extrato bruto de acetato de etila também a 600 ppm contra a espécie receptora E. heterophylla, causou uma diminuição de 63,6% e 72% do comprimento do hipocótilo e radícula, respectivamente, ambos em comparação com seus respectivos brancos (água destilada). Através do estudo fitoquímico foi proposta a estrutura de um diterpeno, por meio do fracionamento e purificação do extrato bruto de éter de petróleo, e um composto, cuja estrutura não foi ainda completamente elucidada, este a partir do extrato bruto de metanol. Os efeitos alelopáticos apresentados pelas raízes do Capim Annoni-2, foram bastante efetivos, podendo estes serem atribuídos as substâncias fitotóxicas isoladas nesse estudo. / The Grass Annoni-2 (Eragrostis plana Nees), considered a noxious invasive and difficult to eradicate plant has the capacity to dominate the environment they are in, superseding Agrieconomic and native species. Part of this ability is related to allelopathic effects caused by allelochemicals released by this species. Thus, the identification of these allelochemicals can be a good alternative for the production of bio-herbicides. In this study, we determined the allelopathic potential of crude extracts of petroleum ether, ethyl acetate and methanol from the root of E. plana Nees collected in the summer in the experimental area of the course of Agronomy UTFPR - Pato Branco campus, as well as a phytochemical study for structural elucidation of potential allelochemicals. The allelopathic potential was assessed from bioassays of germination and growth of radicle and hypocotyl, using two receptor species (Ipomoea grandifolia and Euphorbia hetetophylla) and three concentrations of crude extracts (200, 400 and 600 ppm). As a result it was found that crude extracts of petroleum ether and ethyl acetate act mainly on the kinetics of the germination process by slowing it, while the crude methanol extract worked, especially in reducing the germination inhibiting 75.4% in comparison with blank (distilled water), causing deformities, and even death of seedlings these data to the recipient E. heterophylla, most affected. Regarding the growth bioassay hypocotyl and radicle, crude methanol extract was the least effective, highlighting the crude extract of petroleum ether at 600 ppm against receiving I. grandifolia species, causing a decrease in the growth of radicle and hypocotyl 66.3% and 65.5%, respectively, and the crude ethyl acetate extract also receiving 600 ppm against E. heterophylla caused a decrease of 63.6% and 72% of the length of the hypocotyl and radicle respectively, both compared with their white (distilled water). Through phytochemical study was proposed structure of a diterpene, through the fractionation and purification of the crude extract of petroleum ether, and a compound whose structure has not been fully elucidated, this from crude methanol extract. The allelopathic effects shown by the roots of the grass Annoni-2, were quite effective, these can be attributed to the isolated phytotoxic substances in this study.
13

Synthesis, characterization and application of a novel biosorbent-magnetic nanomaterial cross-linked with cyclodextrin using epichlorohydrin and hexamethylene diisocyanate as adsorbents for heavy metals and organics

Pholosi, Agnes 03 1900 (has links)
D. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology / In the present era of water resources scarcity, efficient treatment of wastewater is a major prerequisite especially for growing economy. Numerous approaches have been studied for the development of cheaper and more effective adsorbents for removal of both organic and inorganic pollutants from wastewater. The present study seeks to harness the potential of biosorption and nanotechnology by producing more efficient, selective, mechanically stable and effective adsorbents for removal of organic and inorganic pollutants. The biosorbent-magnetic nanomaterial was synthesized by coating magnetite nanoparticles with sodium hydroxide treated pine cone by co-precipitation method. Magnetite coated pine bio-composite was then modified by cross-linking with hexamethylene diisocyanate and epichlorohydrin to the molecular recognition compound “cyclodextrin”. These novel biosorbent-magnetic nanoparticle materials were explored in overcoming the drawbacks of the biosorbent alone and selectively remove inorganic and organic pollutants from complex matrices. The synthesized materials were characterized by several analytical techniques including, Fourier Transformed Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM–EDX), Transmission Electron Microscopy (TEM), Brunauer, Emmett and Teller Isotherm (BET) surface area analysis, X-ray Photoelectron Spectroscopy (XPS), Vibrating Sample Magnetometer (VSM) and pH at point of zero charge (pHpzc). Sodium hydroxide treated pine cone and magnetite coated pine cone were applied for both chromium(VI) and arsenic(III) adsorption while the magnetite coated pine cone, magnetite coated pine cone crosslinked to cyclodextrin using both epichlorohydrin and hexamethylene diisocyanate were applied for 4-nitrophenol removal from aqueous solution. Batch adsorption studies were performed to optimize operating parameters such as solution pH, adsorbent dose, contact time, temperature and initial concentration. Pseudo first, pseudo second, intraparticle diffusion, pore and film diffusion kinetic models were determined to investigate the mechanism of adsorption process. Coefficient of correlation, r2, and variable error, methods were also applied in the determination of the best fit of the kinetic method. Structural characterization of magnetite coated pine cone and the magnetite coated pine crosslinked to cyclodextrin using 1,6-hexamethylene diisocyanate and epichlorohydrin were confirmed by characterization techniques applied. The adsorption of Cr(VI), As(III) and 4-nitrophenol was found to be dependent on the solution pH, adsorbent dose, initial concentration, temperature and ionic strength. Kinetic modelling revealed that the adsorption of Cr(VI), As(III) and 4-nitrophenol is controlled by pseudo second order kinetic model suggesting surface adsorption and intraparticle diffusion model. Intraparticle, pore and film diffusion models gave further insight into the controlling diffusion mechanism involved in the adsorption process for all pollutants investigated. Equilibrium studies indicated that the adsorption of all pollutants followed Langmuir isotherm indicating that adsorption sites are homogeneous in nature. The obtained thermodynamic parameters demonstrated that the adsorption of Cr(VI), As(III) and 4-nitrophenol were spontaneous, favourable and endothermic in nature. Anionic effect positively affected Cr(VI) and As(III) removal but had a negative effect on the 4-nitrophenol adsorption. Adsorption of 4-nitrophenol onto the nanocomposite adsorbents was attributed to multiple adsorbent-adsorbate interactions such as hydrogen bonding, hydrophobic attraction and guest host interaction. Magnetite coated pine better removed Cr(VI) and As(III) from aqueous solution than NaOH treated pine cone biomaterial while the magnetite coated pine crosslinked to cyclodextrin using 1,6-hexamethylene diisocyanate exhibited better adsorption performance for 4-nitrophenol removal than the nanocomposite crosslinked using epichlorohydrin and the magnetite coated pine cone.
14

Digestion characteristics of forages, including perennial ryegrass at different stages of maturity, and supplementary feeding for dairy cows grazing pasture : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science, Institute of Food Nutrition and Human Health, Massey University, Palmerston North, New Zealand

Chaves, Alexandre Vieira January 2003 (has links)
This thesis defines digestion kinetics for perennial ryegrass (Lolium perenne L.), which is the main component of diets fed to dairy cows in New Zealand. Chemical composition and digestion kinetics were measured in fresh minced ryegrass as it matured and leaf, stem and inflorescence of several grass species. In sacco and in vitro incubations were used to define rates of degradation and nutrient release. Two short-term grazing trials were used to evaluate contrasting silages as supplements for cows fed restricted amounts of summer pasture. The minced preparation of ryegrass resulted in a similar distribution of dry matter (DM) between particle size fraction and rumen digesta from cows fed pasture. Mincing released 0.46 – 0.80 of crude protein into the soluble fraction, with highest proportions for mature grasses which had low CP concentrations (about 8 g CP/100 g DM). In contrast, the majority of fibre remained in the insoluble fraction but rates of degradation (k) approximately halved as grass matured. In vitro yield of VFA was similar for immature and mature minced ryegrass (after 12 hours VFA was equivalent to about 30% of DM), even though ammonia concentration declined to very low values for stem and mature grass. This suggests the rapid initial microbial growth was able to sustain a high level of DM degradation to VFA with mature grass. The summer pasture used for silage supplementation was of uncharacteristically good quality so the expected contrasts between maize, pasture, sulla (Hedysarum coronarium), lotus (Lotus corniculatus) and sulla/maize silage mixtures were less than expected. Milk responses to lotus silage supplements were greater than other silages (e.g.: 290 g milksolids from 54 MJ ME by lotus versus 110 g milksolids from about 50 MJ ME supplied by other silages). Pasture substitution was low (0.06 – 0.33). The Cornell Net Carbohydrate and Protein System (CNCPS) was chosen for evaluation of cow trial data because it uses feed degradation parameters as input variables to estimate nutrient supply. Model prediction of milk yield matched observed values when cows maintained liveweight. Milk yield was underestimated at low intakes and overestimated at high intakes because no allowance is made for nutrient partitioning between milk production and liveweight change.
15

Dřeviny ve veřejném městském prostoru / The woody plants in the public city space

Markevičová, Vendula January 2017 (has links)
This tesis are about the mutual relation between the woody plants and the city public space, more precisely between the architectural composition and its elements. Woody plants, particulalry the trees,are under the same aesthetical rules as all the other elements of the public space, but at the same time are the living organisms, that are under the rules of nature. The thesis present five thematic groups of information, thats are necessary to know for the design of the woody plants in the city public space. On the base of this information the thesis review the streets and the squares of the city Brno and prove no contradiction between the aesthetical rules and the rules of nature. Contrarily, they support each other. It proves, that the high quality city space with the woody plants, is possible to create only with the knowledge of the both rules and their aplications.

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